KRAS mutation is a negative predictive biomarker of anti-EGFR agents in patients with metastatic colorectal cancer (mCRC), and remains an elusive target. Pelareorep, a double-stranded RNA virus selectively replicates in KRAS-mutated cells, and is synergistic with irinotecan. A dose escalation trial of FOLFIRI/bevacizumab [irinotecan (150–180 mg/m²) and pelareorep (1 x 10¹⁰ TCID₅₀–3 x 10¹⁰ TCID₅₀)] was implemented in adult patients with oxaliplatin refractory/intolerant, KRAS-mutant mCRC. Pelareorep was administered intravenously over 1 hour on days 1–5 every 4 weeks. Additional studies included pharmacokinetics, tumor morphology, and immune responses. Among FOLFIRI-naïve patients, the highest dose of FOLFIRI/bevacizumab (180 mg/m² irinotecan) and pelareorep (3 x 10¹⁰ TCID₅₀) was well tolerated, without a dose-limiting toxicity. At the recommended phase II dose, 3 of 6 patients (50%) had a partial response; the median progression-free and overall survival (PFS, OS) were 65.6 weeks and 25.1 months, respectively. Toxicities included myelosuppression, fatigue, and diarrhea. Transmission electron microscopy revealed viral factories (viral collections forming vesicular structures), at various stages of development. Immunogold staining against viral capsid -1 protein demonstrated viral "homing" in the tumor cells. The nucleus displayed sufficient euchromatin regions suggestive of active transcription. Flow cytometry revealed rapid dendritic cell maturation (48 hours) with subsequent activation of cytotoxic T cells (7 days). The combination of pelareorep with FOLFIRI/bevacizumab is safe. The PFS and OS data are encouraging and deserve further exploration. Pelareorep leads to a clear recurrent immune stimulatory response with cytotoxic T-cell activation, and homes and replicates in the tumor.

The development of efficacious therapies targeting metastatic spread of breast cancer to the brain represents an unmet clinical need. Accordingly, an improved understanding of the molecular underpinnings of central nervous system spread and progression of breast cancer brain metastases (BCBM) is required. In this study, the clinical burden of disease in BCBM was investigated, as well as the role of aldehyde dehydrogenase 1A3 (ALDH1A3) in the metastatic cascade leading to BCBM development. Initial analysis of clinical survival trends for breast cancer and BCBM determined improvement of breast cancer survival rates; however, this has failed to positively affect the prognostic milestones of triple-negative breast cancer (TNBC) brain metastases (BM). ALDH1A3 and a representative epithelial–mesenchymal transition (EMT) gene signature (mesenchymal markers, CD44 or Vimentin) were compared in tumors derived from BM, lung metastases (LM), or bone metastases (BoM) of patients as well as mice after injection of TNBC cells. Selective elevation of the EMT signature and ALDH1A3 were observed in BM, unlike LM and BoM, especially in the tumor edge. Furthermore, ALDH1A3 was determined to play a role in BCBM establishment via regulation of circulating tumor cell adhesion and migration phases in the BCBM cascade. Validation through genetic and pharmacologic inhibition of ALDH1A3 via lentiviral shRNA knockdown and a novel small-molecule inhibitor demonstrated selective inhibition of BCBM formation with prolonged survival of tumor-bearing mice. Given the survival benefits via targeting ALDH1A3, it may prove an effective therapeutic strategy for BCBM prevention and/or treatment.

TNF-related apoptosis-inducing ligand (TRAIL) and an agonistic antibody against the death-inducing TRAIL receptor 5, DR5, are thought to selectively induce tumor cell death and therefore, have gained attention as potential therapeutics currently under investigation in several clinical trials. However, some tumor cells are resistant to TRAIL/DR5–induced cell death, even though they express DR5. Previously, we reported that DR5 is transported into the nucleus by importin β1, and knockdown of importin β1 upregulates cell surface expression of DR5 resulting in increased TRAIL sensitivity in vitro. Here, we examined the impact of importin β1 knockdown on agonistic anti-human DR5 (hDR5) antibody therapy. Drug-inducible importin β1 knockdown sensitizes HeLa cells to TRAIL-induced cell death in vitro, and exerts an antitumor effect when combined with agonistic anti-hDR5 antibody administration in vivo. Therapeutic importin β1 knockdown, administered via the atelocollagen delivery system, as well as treatment with the importin β inhibitor, importazole, induced regression and/or eradication of two human TRAIL-resistant tumor cells when combined with agonistic anti-hDR5 antibody treatment. Thus, these findings suggest that the inhibition of importin β1 would be useful to improve the therapeutic effects of agonistic anti-hDR5 antibody against TRAIL-resistant cancers.

Dysregulation of DNA methylation is an established feature of breast cancers. DNA demethylating therapies like decitabine are proposed for the treatment of triple-negative breast cancers (TNBC) and indicators of response need to be identified. For this purpose, we characterized the effects of decitabine in a panel of 10 breast cancer cell lines and observed a range of sensitivity to decitabine that was not subtype specific. Knockdown of potential key effectors demonstrated the requirement of deoxycytidine kinase (DCK) for decitabine response in breast cancer cells. In treatment-naïve breast tumors, DCK was higher in TNBCs, and DCK levels were sustained or increased post chemotherapy treatment. This suggests that limited DCK levels will not be a barrier to response in patients with TNBC treated with decitabine as a second-line treatment or in a clinical trial. Methylome analysis revealed that genome-wide, region-specific, tumor suppressor gene–specific methylation, and decitabine-induced demethylation did not predict response to decitabine. Gene set enrichment analysis of transcriptome data demonstrated that decitabine induced genes within apoptosis, cell cycle, stress, and immune pathways. Induced genes included those characterized by the viral mimicry response; however, knockdown of key effectors of the pathway did not affect decitabine sensitivity suggesting that breast cancer growth suppression by decitabine is independent of viral mimicry. Finally, taxol-resistant breast cancer cells expressing high levels of multidrug resistance transporter ABCB1 remained sensitive to decitabine, suggesting that the drug could be used as second-line treatment for chemoresistant patients.

Physical and chemical DNA-damaging agents are used widely in the treatment of cancer. Double-strand break (DSB) lesions in DNA are the most deleterious form of damage and, if left unrepaired, can effectively kill cancer cells. DNA-dependent protein kinase (DNA-PK) is a critical component of nonhomologous end joining (NHEJ), one of the two major pathways for DSB repair. Although DNA-PK has been considered an attractive target for cancer therapy, the development of pharmacologic DNA-PK inhibitors for clinical use has been lagging. Here, we report the discovery and characterization of a potent, selective, and orally bioavailable DNA-PK inhibitor, M3814 (peposertib), and provide in vivo proof of principle for DNA-PK inhibition as a novel approach to combination radiotherapy. M3814 potently inhibits DNA-PK catalytic activity and sensitizes multiple cancer cell lines to ionizing radiation (IR) and DSB-inducing agents. Inhibition of DNA-PK autophosphorylation in cancer cells or xenograft tumors led to an increased number of persistent DSBs. Oral administration of M3814 to two xenograft models of human cancer, using a clinically established 6-week fractionated radiation schedule, strongly potentiated the antitumor activity of IR and led to complete tumor regression at nontoxic doses. Our results strongly support DNA-PK inhibition as a novel approach for the combination radiotherapy of cancer. M3814 is currently under investigation in combination with radiotherapy in clinical trials.

Detailed landform mapping of key areas in the Vale of Pickering, supported by LiDAR interpretation, has produced sufficient evidence to establish a reinterpretation of the Mid to Late Pleistocene chronology of the Vale of Pickering by defining the margins of two temporally distinct proglacial lakes and reaching a new understanding of the origin of some well-documented geomorphological features. The main significance of the mapping has been to establish that the Hutton Buscel terrace probably originated by lateral erosion along the southern edge of the Corallian Group dip slope of the North York Moors prior to deposition of a broad alluvial plain below a 70 m strandline. Traces of a comparable feature were also located below the Chalk Group escarpment on the southern side of the Vale of Pickering. Perhaps of equal significance has been confirmation that the younger of the two lakes, which has a 45 m shoreline, was possibly connected to Lake Humber in the Vale of York through the Derwent Valley. Evidence for such a lake was provided by mapped shorelines at Malton and Pickering that appear compatible with shorelines in Lake Humber. To account for deep erosion of the Derwent and Mere valleys and the occurrence of laminated clays at c. 65 m, below a 70 m shoreline above Crambe, regional uplift has been evoked post the older 70 m lake. In-valley alluvial fans have been mapped for the first time in Newton Dale and Thornton Dale.

The invertebrate trace fossils Selenichnites rossendalensis and Crescentichnus tesiltus are recorded and described from the Middle Jurassic Gristhorpe Member of the Cloughton Formation of the Cleveland Basin. This is the first record of these ichnospecies from the basin and now completes the occurrence of these and other traces assumed to have been made by limulids from all three non-marine formations of the Ravenscar Group.

Field evidence shows that emplacement of Devonian granites in northern England overlaps in space and time with the end of the supposed Acadian deformation in their country rocks. The age of this Acadian event in England and Wales is in need of review because of revised Rb-Sr and K-Ar decay constants and recently acquired radiometric ages on the granites.

Published K-Ar and Ar-Ar cleavage ages recalculated to the new decay constants range from 404 to 394 Ma (Emsian, Early Devonian). Emplacement of the Skiddaw and Weardale granites at 398.8 ± 0.4 and 399.3 ± 0.7 Ma respectively is indicated by U-Pb zircon ages, and is compatible with the field evidence. However, emplacement of the Shap Granite at a Re-Os molybdenite age of 405.2 ± 1.8 Ma and at the youngest U-Pb zircon age of 403 ± 8 Ma matches the field evidence less well. The apparent paradox in these ages is resolved if the K-Ar ages record only the end of millions of years of cleavage formation. An earlier cluster of K-Ar and Ar-Ar cleavage ages at 426–420 Ma (Ludlow to Přídolí, late Silurian) dates a pre-Acadian resetting event soon after Iapetus closure, an event of uncertain significance.

Ion microprobe U-Pb zircon ages for the Shap Granite have a mean of 415.6 ± 1.4 Ma but a range of 428–403 Ma, compatible with a long magmatic history. Thermal considerations suggest that this history was not at the upper crustal emplacement site but in a mid-crustal mush zone, now preserved at about 10 km depth as a component of the Lake District and North Pennine batholiths.

Oil residues occur as solid bitumen in mineralized zones within the Devonian Weardale Granite of the northern Pennines, northern England. Comparable residues are present in the overlying Mississippian rocks and were probably derived from a Carboniferous source, i.e. during later mineralization of the granite. The bitumen was already solidified during fluorite mineralization, which does not contain oil inclusions. The residues do not show the high thermal maturity of organic matter in the region altered by the earliest Permian Whin Sill. Like the sulphide-fluorite mineralization, oil emplacement post-dated intrusion of the sill. Pyrite associated with the oil residues is enriched in trace elements including lead, silver, gold, selenium and tellurium, which suggests that mineralizing fluids at least shared pathways with migrating hydrocarbons and possibly also suggests undiscovered valuable metal resources.

Commonly used model teeth are so far uniform in color and hardness. There is no discrimination between enamel and dentin part of a tooth. This condition makes it difficult to train a preparation technique, which is adapted to real tooth substance. The aim of this study was to design and establish a 3D printed tooth with different layers for enamel and dentin for education in crown preparation. A printable tooth with different layers for enamel and dentin was designed, and all 38 fourth-year dental students in the first clinical course in prosthodontics and 30 experienced dentists were trained during a voluntary hands-on course in 2019. Prior to the study, the students had used standard model teeth and real-teeth models in their preclinical education. They had experience in caries removal and preparation on real patients. The perceived benefits of the 3D printed tooth were evaluated by a questionnaire. All individuals in both groups completed the questionnaire, for a 100% response rate. The results showed that the printed tooth was given an overall mean grade of 2.3 (students) and 2.0 (experts) on a scale from 1=excellent to 5=poor. The difference in hardness between the dentin and enamel layer was given a mean of 2.4 (students and experts) and the difference in color a 1.7 (students) and 1.8 (experts). The tooth model with the prepared tooth illustrating an ideal preparation was graded 1.6 (students and experts). In this study, the students had the opportunity to learn a correct crown preparation on a printed tooth with different material properties for enamel and dentin. The learning effect with this tooth model was rated as good on the questionnaire by both students and expert dentists.

This article describes the development of medical competencies for oral medicine specialty training in the UK and Ireland by a collaborative working group using a modified Delphi technique. The current specialty training curriculum for oral medicine (OM) in the UK was developed by a working group including members of the British Society for Oral Medicine (BSOM) and members of the Specialty Advisory Committee for Additional Dental Specialties (SACADS) and adopted by the UK General Dental Council (GDC) in 2010. When the curriculum was developed, the entry requirements for specialty training in OM included undergraduate degrees in both dentistry and medicine. At the time of adoption, the requirement for a medical degree was removed. Medical competencies were assumed to have been delivered in medical undergraduate and postgraduate training. Accordingly, there was a need to define the medical competencies for OM specialty training to benefit trainees, trainers, and assessors. In 2018, a group comprising specialty trainers, recent former specialty trainees, and current specialty trainees in OM held face-to-face meetings in addition to email discussions and developed an updated curriculum document to better reflect the medical competencies required in specialty training. A collaborative modified Delphi approach was used to evaluate medical foundation competencies and to include only those that were considered relevant to OM specialty training. A list of relevant and achievable medical competencies was determined that has been approved by SACADS and will be incorporated into a revised OM curriculum from the UK GDC. The newly agreed-upon document for medical competencies in OM specialty training will serve as a reference for trainees, trainers, and assessors and reflects a successful use of a modified Delphi approach.

The aims of this study were to qualitatively assess dental public health (DPH) residents’ perspectives on teaching methods for DPH competencies and to develop and implement a case-based simulation to address those competencies, constructed on the basis of the qualitative assessment. Focus group discussions were conducted with 18 DPH residents enrolled in two university-based DPH programs. Topic areas discussed in the two focus groups were perceived value of DPH competencies, ways to acquire new DPH skills/abilities, and additional skills/abilities needed by DPH residents. The focus groups’ responses showed that the residents felt competent in the analytical thinking competencies such as research methodology and critiquing literature. They emphasized the importance of learning leadership skills and reported feeling somewhat uncertain about their mastery of the policy and advocacy and system evaluation competencies. Of the two distinct categories of DPH skills and competencies— analytical/critical thinking and practical competencies—these residents reported that a greater proportion of time needed to be devoted to integrating the practical competencies into their education. Based on the residents’ feedback, the authors developed a structured seminar series taking a case-based approach to simulate real-world DPH problems, using real and semi-hypothetical planning projects to meet the residents’ perceived needs and covering gaps between didactic learning and practice.

Dental students’ ability to critique team performance in dental school team clinics is a key component of dental education. The aim of this study was to determine if students’ perceptions of their team leaders’ openness of communication, cooperative decision making, and well-defined goals were positively related to the students’ improvement-oriented voice behavior and willingness to raise concerns in the clinical environment. This study used a voluntary 12-question survey, distributed via email to all 311 students at the University of Nevada, Las Vegas School of Dental Medicine after completion of the spring 2017 semester. Eighty-seven students responded, for a response rate of 28%. Responses were stratified by team, class year, and gender, and the quantitative distribution of answers to each question was correlated with each other. Team leader collaborative qualities, which included openness for communication, cooperative decision making, and well-defined goals, were found to have a significant positive relationship with students’ willingness to both raise concerns and make suggestions. Additionally, when measured by class year and gender, team differences in voice behavior assessment by students across the teams were found to be independent of class year, and no significant differences were found by gender. These results suggested that, to maintain high levels of communication, proper reporting of concerns, and a high standard of care, dental schools should encourage team leaders to enhance their capacity to present active collaborative behaviors in the school’s clinic. The study also highlighted potential opportunities for further study of faculty traits and development in the dental school team model.

Dental students in North American dental schools are exposed to faculty members with various professional backgrounds. These faculty members may include dentists, dental hygienists, and scientists without clinical dental credentials. The practice of dental hygienists’ educating predoctoral dental students has not been well documented. The aims of this two-part study were to investigate the parameters of didactic, preclinical, and clinical instruction of dental students by dental hygienist faculty members in North American dental schools and to explore dental students’ perceptions of this form of teaching. In part one, a survey was sent electronically to the clinical or academic affairs deans of all 76 American Dental Education Association (ADEA) member dental schools in 2017. Twenty-nine responded, for a 38.2% response rate. In 76% of the responding schools, dental hygienists were teaching dental students. Most respondents reported that, in their schools, the minimum degree required to teach didactically was a master’s, while a bachelor’s degree was required for preclinical and clinical courses. There was no significant association between dental hygienists’ instructing dental students and having a dental hygiene educational program at the institution. In part two of the study, a questionnaire was completed by 102 graduating dental students (85% response rate) at one U.S. university to evaluate the impact of dental hygienist educators. Among the respondents, 87% reported feeling that dental hygienists were very effective educators. There were no significant differences in responses between traditional and advanced standing international dental students. This study found that dental hygienists were educating dental students in many North American dental schools and were doing so in curricular content beyond periodontics and that their educational contributions at a sample school were valued by the dental students there.

Few studies have been published on thesis completion experiences of master’s degree students. However, for doctoral students, dissertation completion has been found to be dependent on individual, relational, and institutional factors. The aim of this study was to examine dental hygienists’ perceptions of their experiences completing a thesis as a requirement for an advanced degree. A qualitative phenomenological research design was used utilizing virtual focus groups with a national purposive sample of dental hygienists (n=25) who had graduated from a degree program in which a thesis was a requirement for the degree. Data analysis used an inductive approach to identify themes using Liechty et al.’s framework of individual, relational, and institutional factors impacting completion of a dissertation. Liechty et al.’s framework is based on Vygotsky’s sociocultural theory of learning. In the results, individual factors identified included family/work responsibilities, lack of understanding of the thesis process, time management, health issues, and reaching personal and professional goals. Relational factors focused primarily on positive and negative experiences with the thesis advisor/committee and support from expert peers/family. Institutional factors included the thesis structure, financial concerns, and challenges in recruiting research participants. This study found many factors influencing the thesis experience that may help guide the process in graduate degree programs. In addition, the findings suggest a need to provide mentoring and support for thesis advisors and committee members to more effectively guide students through the thesis process. Effective modifications of these may improve retention of students and facilitate timely completion of thesis research.

Changes in U.S. health care delivery systems and Commission on Dental Accreditation standards provide impetus for interprofessional education (IPE) and collaborative practice, but roadmaps for engaging dental and dental hygiene faculty to incorporate IPE in a systematic manner are limited. The purpose of this report is to describe the process for creating a strategy and gathering a variety of baseline data to use for determining objectives and metrics and the subsequent development of an IPE strategic plan at the University of North Carolina (UNC) at Chapel Hill Adams School of Dentistry (SOD). SOD IPE committee members included representation from the UNC Schools of Dentistry, Medicine, Pharmacy, and Business. A three-phase framework was developed. Phase 1 (IPE assessment) was an internal environmental scan including a 2017 faculty survey, departmental mapping of IPE activities, comparison of UNC with national results on the IPE component of the American Dental Education Association (ADEA) survey of dental school seniors (2016 graduating class), identification of faculty joint/adjunct appointments at other UNC schools, and a strengths, weaknesses, opportunities, threats (SWOT) analysis. Phase 2 (visioning) consisted of development of IPE mission, vision, and priorities. In Phase 3 (implementation), priorities were developed. Data-gathering led to a strategic plan with three objectives: 1) increase faculty engagement and recognition, 2) develop predoctoral dentistry and dental hygiene IPE curricula, and 3) develop an infrastructure that supports IPE. Specific initiatives and activities, supporting metrics, and estimated costs were developed for each objective. The framework guided a systematic, transparent, and organized process for collecting and monitoring the evidence and directing activities. A three-year strategic plan for IPE was developed in 2017, and implementation is ongoing.

Clinical teaching is a cornerstone of health sciences education; it is also the most challenging aspect. The University of Pittsburgh Schools of Dental Medicine, Nursing, and Pharmacy developed a new evidence-based interprofessional course framed as a faculty learning community (FLC) around the principles of learning in a clinical environment. The aim of this study was to assess the overall effectiveness of this two-semester FLC at four health professions schools in academic year 2014-15. The assessment included anonymous participant surveys in each session and an anonymous end-of-course survey. Thirty-five faculty members from dental, health and rehabilitation sciences, nursing, and pharmacy enrolled in the FLC, with six to 32 enrollees attending each session. All attendees at each session completed the session evaluation surveys, but the attendance rate at each session ranged from 17.1% to 91.4%. Sixteen participants (46%) completed the end-of-course survey. The results showed overall positive responses to the FLC and changes in the participants’ self-reported knowledge. Session surveys showed that the participants found the FLC topics helpful and appreciated the opportunity to learn from each other and the interprofessional nature of the FLC. Responses to the end-of-course survey were in alignment with the individual session surveys and cited specific benefits as being the content, teaching materials, and structured discussions. In additional feedback, participants reported interest to continue as a cohort and to extend the peer-support system beyond the FLC. This outcomes assessment of the first round of the FLC confirmed that this cohort-based faculty development in an interprofessional setting was well received by its participants. Their feedback provided valuable insights for changes to future offerings.

The aim of this cross-sectional study was to examine the faculty mentoring practices in seven dental schools in the U.S. A 34-item survey was administered electronically to dental faculty members of all ranks, tracks, and job categories in seven dental schools using faculty listservs. Survey questions addressed current mentoring practices in which the faculty members were involved; their perceptions of those mentoring practices; their perceived characteristics of an ideal mentoring program, mentor, and mentee; perceived best practices; and respondents’ demographics. The survey was conducted from October 2017 to February 2018. A total of 154 surveys were completed (response rate 22%). Over 58% (90/154) of the respondents reported receiving no mentoring; 31.9% (49/154) said they received informal mentoring; and 9.7% (15/154) received formal mentoring. Of the 64 respondents who received mentoring, both formal and informal, 92.2% (59/64) were full-time faculty, and 7.8% (5/64) were part-time faculty (p=0.001). Approximately 39% of the respondents indicated that their mentoring program was not overseen by anyone and that participation was voluntary. The top three perceived benefits of mentoring were increased overall professional development, development of a career plan, and increased professional networks. The three most important characteristics of an ideal mentoring program for the respondents were a program based on the needs of the mentee, a mentor who has the desire to help the mentee, and a mentee who is eager to learn. The results of this study showed a very low level of formal or informal faculty mentoring programs in the dental schools surveyed. Future studies are needed to determine best practices and strategies to expand and enhance mentoring of faculty members.

The number of citations an article receives is an important indicator to quantify its influence in its field. The aim of this study was to identify and analyze the characteristics of the 50 top-cited articles addressing dental education published in two journals dedicated to dental education (European Journal of Dental Education and Journal of Dental Education). The Web of Science database was searched to retrieve the 50 most-cited articles from the two journals in December 2018. The top-cited articles were analyzed for journal of publication, number of citations, institution and country of origin, year of publication, study type, keywords, theme and subtheme, and international collaborations. The results showed the 50 top-cited articles were cited between 24 and 146 times each. The majority of these top-cited articles (n=34) were published in the Journal of Dental Education. Half (n=25) of the articles were by authors in the U.S. The most common study types were surveys (n=26) and reviews (n=10). The main themes of these top-cited articles were curriculum and learner characteristics. This bibliometric analysis can serve as a reference for recognizing studies with the most impact in the scholarship of dental education.

Despite advances in oral health care, inequalities in oral health outcomes persist due to problems in access. With proper training, primary care providers can mitigate this inequality by providing oral health education, screening, and referral to advanced dental treatment. Diverging sets of oral health competencies and guidelines have been released or endorsed by multiple primary care disciplines. The aim of this study was to transform multiple sets of competencies into Entrustable Professional Activities (EPAs) for oral health integration into primary care training. A scoping review of the literature between January 2000 and December 2016 was conducted according to PRISMA methodology to identify all existing sets of competencies. The following primary care disciplines were included in the search: allopathic/osteopathic medical schools and residency programs in family medicine, internal medicine, and pediatrics; physician assistant programs; and nurse practitioner programs. Competencies were compared using the Health Resources and Services Administration Integration of Oral Health and Primary Care Practice competencies as the foundational set and translated into EPAs. The resulting EPAs were tested with a reactor panel. The scoping review produced 1,466 references, of which 114 were selected for full text review. Fourteen competencies were identified as being central to the integration of oral health into primary care. These were converted to seven EPAs for oral health integration into primary care and were mapped onto Accreditation Council for Graduate Medical Education residency competency domains as well to the Association of American Medical Colleges EPAs for graduating medical students. The resulting EPAs delineate the essential, observable work required of primary care providers to ensure that oral health is treated as a critical determinant of overall health.

Interprofessional education (IPE) is based on collaborative practices that increase the occasions for communication among those in various health professions. However, there is a paucity of literature about the effectiveness of IPE programs in health professions education. The aim of this systematic review and meta-analysis was to objectively assess the literature on the effectiveness of IPE in improving health professions students’ attitudes after training. The major scholarly databases were searched for relevant IPE studies involving predoctoral health professions students. Two independent researchers selected the studies, extracted the data, and assessed the quality of the studies. Meta-analyses of the outcomes were performed using random effects models. Sixteen articles were ultimately selected for detailed review and meta-analysis. The meta-analysis showed that IPE training had a significant influence on students’ understanding of collaboration and resulted in better attitudes about interprofessional teamwork. Subscale analysis showed that one subscale score (roles and responsibilities) did not statistically significantly improve after IPE training (p=0.06), whereas the other four subscale items showed statistically significant improvements (p<0.01). The test for overall effects showed that IPE training had a significantly positive influence on students’ attitudes about IPE (Z=6.85, p<0.01). Subgroup results showed that medical students had more positive attitudes about IPE than did dental students. Regardless of profession, women students responded with significantly more positive feedback than did men students (p=0.02). These results suggest that intervention through IPE training has had positive effects in health professions education. Gender was an important factor impacting the outcomes of IPE. However, further clinical practice interventions may be helpful to enhance the IPE competence of health professions students.

Purpose: The purpose of this study was to identify current requirements for initial licensure and entry into the dental hygiene profession across state dental and dental hygiene licensing boards in the United States.Methods: A non-experimental study design was used to study dental and dental hygiene board licensing requirements in the United States, Puerto Rico and the Virgin Islands. Each regulatory board website was searched for requirements for entry-level dental hygiene licensure. Requirements were recorded on an Excel spreadsheet. State dental practice acts were reviewed to gather further information and 20 regulatory bodies were contacted to verify accuracy. Descriptive statistics were used to analyze data.Results: Information from a total of 52 dental boards (n=52) was examined for this study. Nearly all boards (n=51, 98.1%), with the exception of Alabama, required completion of entry-level education from a CODA accredited dental hygiene program and successful completion of the National Board Dental Hygiene Examination. Most states (n=51, 98.1%), except Delaware, also required a live-patient, a clinical board examination. Application fees ranged from $47.70 to $600. States varied considerably in terms of requirements for background checks, age, military status, and infection control training.Conclusion: Although the majority of regulatory bodies require completion of entry-level dental hygiene education from a CODA accredited program and successful completion of national board and a live-patient, clinical examination, there is considerable variation in other additional requirements for initial dental hygiene licensure.

Purpose: The purpose of this study was to determine strength of muscles involved with instrumentation (scaling) by dental hygienists and the additive effects of cellular (mobile) phone usage, as indicated by measurements of muscular force generation.Methods: A convenience sample of licensed dental hygienists currently in clinical practice (n=16) and an equal number of individuals not currently using devices/tools repetitively for work (n=16), agreed to participate in this pilot study. All participants completed a modified cell phone usage questionnaire to determine their use pattern and frequency. Upon completion of the questionnaire, participants' force production in six muscle groups was measured using a hand-held dynamometer. Descriptive statistics were used to analyze the data.Results: A total of 16 licensed dental hygienists (n=16) and 16 participants with no history of using tools/devices repetitively for work (n=16), comprised the experimental and control groups, repectively. The control group generated greater muscle force than the experimental group for the abductor pollicis longus (p=0.045). Significant differences were identified when comparing the low mobile phone users in the experimental group to the control group for the flexor pollicis brevis (p=0.031), abductor pollicis longus (p=0.031), and flexor digitorum (p=0.006), with the control group demonstrating higher muscle force. Years in clinical practice and mobile phone use was shown to have a significant effect on muscular force generation for the flexor pollicis brevis (F=3.645, df=3, p=0.020) and flexor digitorum (F=3.560, df=3, p=0.022); subjects who practiced dental hygiene the longest produced the least amount of muscle force.Conclusion: Results from this pilot study indicate there are no significant additive effects of cell phone use and dental hygiene practice on finger muscles used for instrumentation. However, results indicate that dental hygiene practice demonstrated significant effects on muscular strength as compared to individuals who do not use tools/devices repetitively for work. The small sample size may have impacted results and the study should be repeated with a larger sample.

Purpose: Untreated and poorly controlled diabetes causes increased levels of blood glucose associated with poor periodontal disease outcomes. Dental hygienists can play a significant role in screening patients for diabetes mellitus, leading to referral and early diagnosis. The purpose of this study was to determine the knowledge, attitudes, practices, and barriers faced by clinical dental hygienists regarding diabetes risk assessment and screenings.Methods: A mixed method design was used with a convenience sample of dental hygienists in clinical practice (n=316). A 32 item, electronic survey was validated at item-level, and participants were recruited through multiple dental hygiene Facebook groups. Descriptive statistics were used to analyze the data. The survey also included two open-ended attitude questions that were interpreted using thematic analysis to pinpoint common patterns within the data.Results: Dental hygienists had high knowledge scores regarding diabetes and oral health, although many were unaware of their states' specific statutes and regulations for screening practices. Nearly all (95.9%), were likely to educate and refer patients (82%), although fewer than half (40.9%), were likely to perform chairside screening for diabetes. Emergent themes for barriers to screening were time, money, patient acceptance/willingness, lack of education, not having the proper tools, and states' rules and regulations.Conclusion: Despite high knowledge scores regarding diabetes and oral health, there is a gap in regards to dental hygienists' willingness to perform diabetes screenings in a clinical setting. Dental hygienists should be capable of integrating chairside diabetes screening practices into the process of care with proper training.

Purpose: Measurement of dental plaque is frequently used as an indicator of overall oral health. The purpose of this study was to compare a manual (visual) plaque scoring system (University of Mississippi Oral Hygiene Index, UM-OHI) with an innovative automated digital scoring system.Methods: Mechanically ventilated, intensive care unit (ICU) patients (n=79) were the study population. Informed consent was given by the subject's legally authorized representative. Digital images of dental plaque were taken using an intraoral camera; and the quantity of dental plaque was scored using the UM-OHI and with a digitized automated scoring system. Distributions of dental plaque scores from both methods were plotted. Pearson correlation coefficients and intra-class coefficients were calculated between the two methods.Results: Participant mean age was 57.3 years; respiratory failure was the most prevalent admission diagnosis (55.7%). The mean percentage of dental plaque calculated by the manual method was found to be remarkably higher (67.3% ± 18.7%) than the percentage of dental plaque calculated by the automated scoring method (23.7% ± 15.2%) (p<0.0001). Despite remarkably different distributions of plaque scores, both the automated and manual scoring systems demostrated relatively high correlation (r=0.62) and good reliability (ICC=0.63).Conclusion: The automated digital scoring system resulted in a significantly lower overall percentage of total dental plaque as compared to the UM-OHI manual scoring system. While the automated digital scoring system may be more precise than a manual (visual) scoring system, its use should be weighed against the added effort, cost, and expertise required for the method. Further study is needed to determine whether an automated digital scoring system can be commercialized and is warranted for use outside of research settings.

Purpose: Oral and craniofacial conditions or diseases can impact an individual's health and quality of life. The purpose of this study was to assess the perceived oral health related quality of life (OHRQoL) of children, and evaluate the reported level of agreement between caregivers and their children.Methods: Purposive sampling was used to recruit children ages 8-15, and their caregivers from a dental clinic in a pediatric hospital for this descriptive, cross-sectional study. A modified version of a validated measure, Child Oral Health Impact Profile-Short Form (COHIP-SF), was used for a 22-item questionnaire encompassing three subscales: oral health, functional well-being, and social emotional well-being. Two additional items were included to assess child/caregiver's level of agreement. A dental chart review was also conducted to assess the child's overbite, overjet, and decayed surfaces. Data were analyzed through descriptive statistics and examined for assumptions of normality and linearity.Results: Sixty child/caregiver pairs (n=120) participated in this study. Overbite, overjet and decayed surfaces were not found to be related to any OHRQoL variable, including child/caregiver ratings and overall agreement (p>.05). Average OHRQoL scores for caregivers found to be more positive those of their children (p=.02). Agreement between caregivers and the child's gender was shown to be significant (p=.01). Female child scores differed significantly from males with respect to their caregiver responses (p=.02). Caregivers rated a higher OHRQoL for female children, thus overestimating their female child's reported OHRQoL.Conclusions: The moderate level of agreement found between children and caregivers reinforces the importance of including the child, as well as the caregiver, when assessing OHRQoL.

Purpose: The purpose of this study was to analyze associations between the oral health literacy of refugees and two oral health outcomes: dental care utilization and oral health self-efficacy.Methods: A convenience sample of refugees in the greater Los Angeles area attending English as a second language (ESL) classes sponsored by two refugee assistance organizations was used for this cross-sectional, correlational study. Participants responded to a questionnaire using items from the Health Literacy in Dentistry (HeLD) scale, in addition to items concerning dental care utilization and oral health self-efficacy. Descriptive statistics, chi-square and Fisher's Exact tests were used to analyze results.Results: Sixty-two refugees volunteered to participate (n=62). A majority of the respondents were female from Iraq or Syria, and selected the item “with little difficulty” for all oral health literacy tasks. In regards to dental care utilization, more than half of the respondents were considered high utilizers (63%, n=34) meaning they had visited a dental office within the last year; while a little more than one-third (37%, n=20), were low utilizers, indicating they had either never been to a dental office or it had been more than one year since they had dental treatment. Statistical analysis showed associations between oral health literacy and dental care utilization. However, few associations between oral health literacy and oral health self-efficacy were identified (p=0.0045).Conclusions: Results support the provision of easily obtainable and understandable oral health information to increase oral health literacy and dental care utilization among refugee populations. Future research is needed to examine the oral health literacy among refugees resettling in the United States.

Geranylgeranoic acid (GGA) originally was identified in some animals and has been developed as an agent for preventing second primary hepatoma. We previously have also identified GGA as an acyclic diterpenoid in some medicinal herbs. Recently, we reported that in human hepatoma-derived HuH-7 cells, GGA is metabolically labeled from ¹³C-mevalonate. Several cell-free experiments have demonstrated that GGA is synthesized through geranylgeranial by oxygen-dependent oxidation of geranylgeraniol (GGOH), but the exact biochemical events giving rise to GGA in hepatoma cells remain unclear. Monoamine oxidase B (MOAB) has been suggested to be involved in GGOH oxidation. Here, using two human hepatoma cell lines, we investigated whether MAOB contributes to GGA biosynthesis. Using either HuH-7 cell lysates or recombinant human MAOB, we found that: 1) the MAO inhibitor tranylcypromine dose-dependently downregulates endogenous GGA levels in HuH-7 cells; and 2) siRNA-mediated MAOB silencing reduces intracellular GGA levels in HuH-7 and Hep3B cells. Unexpectedly, however, CRISPR/Cas9-generated MAOB-KO human hepatoma Hep3B cells had GGA levels similar to those in MAOB-WT cells. A sensitivity of GGA levels to siRNA-mediated MAOB downregulation was recovered when the MAOB-KO cells were transfected with a MAOB-expression plasmid, suggesting that MAOB is the enzyme primarily responsible for GGOH oxidation and that some other latent metabolic pathways may maintain endogenous GGA levels in the MAOB-KO hepatoma cells. Along with the previous findings, these results provide critical insights into the biological roles of human MAOB and provide evidence that hepatic MAOB is involved in endogenous GGA biosynthesis via GGOH oxidation.

Many clinical studies and epidemiological investigations have clearly demonstrated that women are twice as likely to develop cholesterol gallstones as men, and oral contraceptives and other estrogen therapies dramatically increase that risk. Further, animal studies have revealed that estrogen promotes cholesterol gallstone formation through the estrogen receptor (ER) α, but not ERβ, pathway. More importantly, some genetic and pathophysiological studies have found that G protein-coupled estrogen receptor (GPER) 1 is a new gallstone gene, Lith18, on chromosome 5 in mice and produces additional lithogenic actions, working independently of ERα, to markedly increase cholelithogenesis in female mice. Based on computational modeling of GPER, a novel series of GPER-selective antagonists were designed, synthesized, and subsequently assessed for their therapeutic effects via calcium mobilization, cAMP, and ERα and ERβ fluorescence polarization binding assays. From this series of compounds, one new compound, 2-cyclohexyl-4-isopropyl-N-(4-methoxybenzyl)aniline (CIMBA), exhibits superior antagonism and selectivity exclusively for GPER. Furthermore, CIMBA reduces the formation of 17β-estradiol-induced gallstones in a dose-dependent manner in ovariectomized mice fed a lithogenic diet for 8 weeks. At 32 μg/day/kg CIMBA, no gallstones are found, even in ovariectomized ERα (^–/–) mice treated with 6 μg/day 17β-estradiol and fed the lithogenic diet for 8 weeks. In conclusion, CIMBA treatment protects against the formation of estrogen-induced cholesterol gallstones by inhibiting the GPER signaling pathway in female mice. CIMBA may thus be a new agent for effectively treating cholesterol gallstone disease in women.­

Fatty liver involves ectopic lipid accumulation and dysregulated hepatic oxidative metabolism, which can progress to a state of elevated inflammation and fibrosis referred to as nonalcoholic steatohepatitis (NASH). The factors that control progression from simple steatosis to NASH are not fully known. Here, we tested the hypothesis that dietary vitamin E (VitE) supplementation would prevent NASH progression and associated metabolic alterations induced by a Western diet (WD). Hyperphagic melanocortin-4 receptor-deficient (MC4R^–/–) mice were fed chow, chow+VitE, WD, or WD+VitE starting at 8 or 20 weeks of age. All groups exhibited extensive hepatic steatosis by the end of the study (28 weeks of age). WD feeding exacerbated liver disease severity without inducing proportional changes in liver triglycerides. Eight weeks of WD accelerated liver pyruvate cycling, and 20 weeks of WD extensively upregulated liver glucose and oxidative metabolism assessed by ²H/¹³C flux analysis. VitE supplementation failed to reduce the histological features of NASH. Rather, WD+VitE increased the abundance and saturation of liver ceramides and accelerated metabolic flux dysregulation compared with 8 weeks of WD alone. In summary, VitE did not limit NASH pathogenesis in genetically obese mice, but instead increased some indicators of metabolic dysfunction.

The pregnane X receptor (PXR) is a nuclear receptor that can be activated by numerous drugs and xenobiotic chemicals. PXR thereby functions as a xenobiotic sensor to coordinately regulate host responses to xenobiotics by transcriptionally regulating many genes involved in xenobiotic metabolism. We have previously reported that PXR has pro-atherogenic effects in animal models, but how PXR contributes to atherosclerosis development in different tissues or cell types remains elusive. In this study, we generated an LDL receptor-deficient mouse model with myeloid-specific PXR deficiency (PXR^MyeLDLR^–/–) to elucidate the role of macrophage PXR signaling in atherogenesis. The myeloid PXR deficiency did not affect metabolic phenotypes and plasma lipid profiles, but PXR^MyeLDLR^–/– mice had significantly decreased atherosclerosis at both aortic root and brachiocephalic arteries compared with control littermates. Interestingly, the PXR deletion did not affect macrophage adhesion and migration properties, but reduced lipid accumulation and foam cell formation in the macrophages. PXR deficiency also led to decreased expression of the scavenger receptor CD36 and impaired lipid uptake in macrophages of the PXR^MyeLDLR^–/– mice. Further, RNA-Seq analysis indicated that treatment with a prototypical PXR ligand affects the expression of many atherosclerosis-related genes in macrophages in vitro. These findings reveal a pivotal role of myeloid PXR signaling in atherosclerosis development and suggest that PXR may be a potential therapeutic target in atherosclerosis management.

Lipid rafts are small, dynamic membrane areas characterized by the clustering of selected membrane lipids as the result of the spontaneous separation of glycolipids, sphingolipids, and cholesterol in a liquid-ordered phase. The exact dynamics underlying phase separation of membrane lipids in the complex biological membranes are still not fully understood. Nevertheless, alterations in the membrane lipid composition affect the lateral organization of molecules belonging to lipid rafts. Neural lipid rafts are found in brain cells, including neurons, astrocytes, and microglia, and are characterized by a high enrichment of specific lipids depending on the cell type. These lipid rafts seem to organize and determine the function of multiprotein complexes involved in several aspects of signal transduction, thus regulating the homeostasis of the brain. The progressive decline of brain performance along with physiological aging is at least in part associated with alterations in the composition and structure of neural lipid rafts. In addition, neurodegenerative conditions, such as lysosomal storage disorders, multiple sclerosis, and Parkinson’s, Huntington’s, and Alzheimer’s diseases, are frequently characterized by dysregulated lipid metabolism, which in turn affects the structure of lipid rafts. Several events underlying the pathogenesis of these diseases appear to depend on the altered composition of lipid rafts. Thus, the structure and function of lipid rafts play a central role in the pathogenesis of many common neurodegenerative diseases.

Lipid rafts, solid regions of the plasma membrane enriched in cholesterol and glycosphingolipids, are essential parts of a cell. Functionally, lipid rafts present a platform that facilitates interaction of cells with the outside world. However, the unique properties of lipid rafts required to fulfill this function at the same time make them susceptible to exploitation by pathogens. Many steps of pathogen interaction with host cells, and sometimes all steps within the entire lifecycle of various pathogens, rely on host lipid rafts. Such steps as binding of pathogens to the host cells, invasion of intracellular parasites into the cell, the intracellular dwelling of parasites, microbial assembly and exit from the host cell, and microbe transfer from one cell to another all involve lipid rafts. Interaction also includes modification of lipid rafts in host cells, inflicted by pathogens from both inside and outside the cell, through contact or remotely, to advance pathogen replication, to utilize cellular resources, and/or to mitigate immune response. Here, we provide a systematic overview of how and why pathogens interact with and exploit host lipid rafts, as well as the consequences of this interaction for the host, locally and systemically, and for the microbe. We also raise the possibility of modulation of lipid rafts as a therapeutic approach against a variety of infectious agents.

ABSTRACT

The luminous marine Gram-negative bacterium Vibrio (Aliivibrio) fischeri is the natural light organ symbiont of several squid species, including the Hawaiian bobtail squid, Euprymna scolopes, and the Japanese bobtail squid, Euprymna morsei. Work with E. scolopes has shown how the bacteria establish their niche in the light organ of the newly hatched host. Two types of V. fischeri strains have been distinguished based upon their behavior in cocolonization competition assays in juvenile E. scolopes, i.e., (i) niche-sharing or (ii) niche-dominant behavior. This study aimed to determine whether these behaviors are observed with other V. fischeri strains or whether they are specific to those isolated from E. scolopes light organs. Cocolonization competition assays between V. fischeri strains isolated from the congeneric squid E. morsei or from other marine animals revealed the same sharing or dominant behaviors. In addition, whole-genome sequencing of these strains showed that the dominant behavior is polyphyletic and not associated with the presence or absence of a single gene or genes. Comparative genomics of 44 squid light organ isolates from around the globe led to the identification of symbiosis-specific candidates in the genomes of these strains. Colonization assays using genetic derivatives with deletions of these candidates established the importance of two such genes in colonization. This study has allowed us to expand the concept of distinct colonization behaviors to strains isolated from a number of squid and fish hosts.

IMPORTANCE There is an increasing recognition of the importance of strain differences in the ecology of a symbiotic bacterial species and, in particular, how these differences underlie crucial interactions with their host. Nevertheless, little is known about the genetic bases for these differences, how they manifest themselves in specific behaviors, and their distribution among symbionts of different host species. In this study, we sequenced the genomes of Vibrio fischeri isolated from the tissues of squids and fishes and applied comparative genomics approaches to look for patterns between symbiont lineages and host colonization behavior. In addition, we identified the only two genes that were exclusively present in all V. fischeri strains isolated from the light organs of sepiolid squid species. Mutational studies of these genes indicated that they both played a role in colonization of the squid light organ, emphasizing the value of applying a comparative genomics approach in the study of symbioses.

ABSTRACT

Human immunodeficiency virus type 1 (HIV-1) establishes lifelong infections in humans, a process that relies on its ability to thwart innate and adaptive immune defenses of the host. Recently, we reported that HIV-1 infection results in a dramatic reduction of the cellular peroxisome pool. Peroxisomes are metabolic organelles that also function as signaling platforms in the innate immune response. Here, we show that the HIV-1 accessory protein Vpu is necessary and sufficient for the depletion of cellular peroxisomes during infection. Vpu induces the expression of four microRNAs that target mRNAs encoding proteins required for peroxisome formation and metabolic function. The ability of Vpu to downregulate peroxisomes was found to be dependent upon the Wnt/β-catenin signaling pathway. Given the importance of peroxisomes in innate immune signaling and central nervous system function, the roles of Vpu in dampening antiviral signaling appear to be more diverse than previously realized. Finally, our findings highlight a potential role for Wnt/β-catenin signaling in peroxisome homeostasis through modulating the production of biogenesis factors.

IMPORTANCE People living with HIV can experience accelerated aging and the development of neurological disorders. Recently, we reported that HIV-1 infection results in a dramatic loss of peroxisomes in macrophages and brain tissue. This is significant because (i) peroxisomes are important for the innate immune response and (ii) loss of peroxisome function is associated with cellular aging and neurodegeneration. Accordingly, understanding how HIV-1 infection causes peroxisome depletion may provide clues regarding how the virus establishes persistent infections and, potentially, the development of neurological disorders. Here, we show that the accessory protein Vpu is necessary and sufficient for the induction of microRNAs that target peroxisome biogenesis factors. The ability of Vpu to downregulate peroxisome formation depends on the Wnt/β-catenin pathway. Thus, in addition to revealing a novel mechanism by which HIV-1 uses intracellular signaling pathways to target antiviral signaling platforms (peroxisomes), we have uncovered a previously unknown link between the Wnt/β-catenin pathway and peroxisome homeostasis.

ABSTRACT

Arthritogenic alphaviruses such as Ross River and Chikungunya viruses cause debilitating muscle and joint pain and pose significant challenges in the light of recent outbreaks. How host immune responses are orchestrated after alphaviral infections and lead to musculoskeletal inflammation remains poorly understood. Here, we show that myositis induced by Ross River virus (RRV) infection is driven by CD11b^hi Ly6C^hi inflammatory monocytes and followed by the establishment of a CD11b^hi Ly6C^lo CX₃CR1⁺ macrophage population in the muscle upon recovery. Selective modulation of CD11b^hi Ly6C^hi monocyte migration to infected muscle using immune-modifying microparticles (IMP) reduced disease score, tissue damage, and inflammation and promoted the accumulation of CX₃CR1⁺ macrophages, enhancing recovery and resolution. Here, we detail the role of immune pathology, describing a poorly characterized muscle macrophage subset as part of the dynamics of alphavirus-induced myositis and tissue recovery and identify IMP as an effective immunomodulatory approach. Given the lack of specific treatments available for alphavirus-induced pathologies, this study highlights a therapeutic potential for simple immune modulation by IMP in infected individuals in the event of large alphavirus outbreaks.

IMPORTANCE Arthritogenic alphaviruses cause debilitating inflammatory disease, and current therapies are restricted to palliative approaches. Here, we show that following monocyte-driven muscle inflammation, tissue recovery is associated with the accumulation of CX₃CR1⁺ macrophages in the muscle. Modulating inflammatory monocyte infiltration using immune-modifying microparticles (IMP) reduced tissue damage and inflammation and enhanced the formation of tissue repair-associated CX₃CR1⁺ macrophages in the muscle. This shows that modulating key effectors of viral inflammation using microparticles can alter the outcome of disease by facilitating the accumulation of macrophage subsets associated with tissue repair.

ABSTRACT

Obesity is associated with increased disease severity, elevated viral titers in exhaled breath, and significantly prolonged viral shed during influenza A virus infection. Due to the mutable nature of RNA viruses, we questioned whether obesity could also influence influenza virus population diversity. Here, we show that minor variants rapidly emerge in obese mice. The variants exhibit increased viral replication, resulting in enhanced virulence in wild-type mice. The increased diversity of the viral population correlated with decreased type I interferon responses, and treatment of obese mice with recombinant interferon reduced viral diversity, suggesting that the delayed antiviral response exhibited in obesity permits the emergence of a more virulent influenza virus population. This is not unique to obese mice. Obesity-derived normal human bronchial epithelial (NHBE) cells also showed decreased interferon responses and increased viral replication, suggesting that viral diversity also was impacted in this increasing population.

IMPORTANCE Currently, 50% of the adult population worldwide is overweight or obese. In these studies, we demonstrate that obesity not only enhances the severity of influenza infection but also impacts viral diversity. The altered microenvironment associated with obesity supports a more diverse viral quasispecies and affords the emergence of potentially pathogenic variants capable of inducing greater disease severity in lean hosts. This is likely due to the impaired interferon response, which is seen in both obese mice and obesity-derived human bronchial epithelial cells, suggesting that obesity, aside from its impact on influenza virus pathogenesis, permits the stochastic accumulation of potentially pathogenic viral variants, raising concerns about its public health impact as the prevalence of obesity continues to rise.

ABSTRACT

Synthesis and cleavage of the cell wall polymer peptidoglycan (PG) are carefully orchestrated processes and are essential for the growth and survival of bacteria. Yet, the function and importance of many enzymes that act on PG in Mycobacterium tuberculosis remain to be elucidated. We demonstrate that the activity of the N-acetylmuramyl-l-alanine amidase Ami1 is dispensable for cell division in M. tuberculosis in vitro yet contributes to the bacterium’s ability to persist during chronic infection in mice. Furthermore, the d,l-endopeptidase RipA, a predicted essential enzyme, is dispensable for the viability of M. tuberculosis but required for efficient cell division in vitro and in vivo. Depletion of RipA sensitizes M. tuberculosis to rifampin and to cell envelope-targeting antibiotics. Ami1 helps sustain residual cell division in cells lacking RipA, but the partial redundancy provided by Ami1 is not sufficient during infection, as depletion of RipA prevents M. tuberculosis from replicating in macrophages and leads to dramatic killing of the bacteria in mice. Notably, RipA is essential for persistence of M. tuberculosis in mice, suggesting that cell division is required during chronic mouse infection. Despite the multiplicity of enzymes acting on PG with redundant functions, we have identified two PG hydrolases that are important for M. tuberculosis to replicate and persist in the host.

IMPORTANCE Tuberculosis (TB) is a major global heath burden, with 1.6 million people succumbing to the disease every year. The search for new drugs to improve the current chemotherapeutic regimen is crucial to reducing this global health burden. The cell wall polymer peptidoglycan (PG) has emerged as a very successful drug target in bacterial pathogens, as many currently used antibiotics target the synthesis of this macromolecule. However, the multitude of genes encoding PG-synthesizing and PG-modifying enzymes with apparent redundant functions has hindered the identification of novel drug targets in PG synthesis in Mycobacterium tuberculosis. Here, we demonstrate that two PG-cleaving enzymes are important for virulence of M. tuberculosis. In particular, the d,l-endopeptidase RipA represents a potentially attractive drug target, as its depletion results in the clearance of M. tuberculosis from the host and renders the bacteria hypersusceptible to rifampin, a frontline TB drug, and to several cell wall-targeting antibiotics.

ABSTRACT

The synergy between Mycobacterium tuberculosis and human immunodeficiency virus-1 (HIV-1) interferes with therapy and facilitates the pathogenesis of both human pathogens. Fundamental mechanisms by which M. tuberculosis exacerbates HIV-1 infection are not clear. Here, we show that exosomes secreted by macrophages infected with M. tuberculosis, including drug-resistant clinical strains, reactivated HIV-1 by inducing oxidative stress. Mechanistically, M. tuberculosis-specific exosomes realigned mitochondrial and nonmitochondrial oxygen consumption rates (OCR) and modulated the expression of host genes mediating oxidative stress response, inflammation, and HIV-1 transactivation. Proteomics analyses revealed the enrichment of several host factors (e.g., HIF-1α, galectins, and Hsp90) known to promote HIV-1 reactivation in M. tuberculosis-specific exosomes. Treatment with a known antioxidant—N-acetyl cysteine (NAC)—or with inhibitors of host factors—galectins and Hsp90—attenuated HIV-1 reactivation by M. tuberculosis-specific exosomes. Our findings uncover new paradigms for understanding the redox and bioenergetics bases of HIV-M. tuberculosis coinfection, which will enable the design of effective therapeutic strategies.

IMPORTANCE Globally, individuals coinfected with the AIDS virus (HIV-1) and with M. tuberculosis (causative agent of tuberculosis [TB]) pose major obstacles in the clinical management of both diseases. At the heart of this issue is the apparent synergy between the two human pathogens. On the one hand, mechanisms induced by HIV-1 for reactivation of TB in AIDS patients are well characterized. On the other hand, while clinical findings clearly identified TB as a risk factor for HIV-1 reactivation and associated mortality, basic mechanisms by which M. tuberculosis exacerbates HIV-1 replication and infection remain poorly characterized. The significance of our research is in identifying the role of fundamental mechanisms such as redox and energy metabolism in catalyzing HIV-M. tuberculosis synergy. The quantification of redox and respiratory parameters affected by M. tuberculosis in stimulating HIV-1 will greatly enhance our understanding of HIV-M. tuberculosis coinfection, leading to a wider impact on the biomedical research community and creating new translational opportunities.

ABSTRACT

Bacteriophages (phages) have been proposed as alternative therapeutics for the treatment of multidrug-resistant bacterial infections. However, there are major gaps in our understanding of the molecular events in bacterial cells that control how bacteria respond to phage predation. Using the model organism Enterococcus faecalis, we used two distinct genomic approaches, namely, transposon library screening and RNA sequencing, to investigate the interaction of E. faecalis with a virulent phage. We discovered that a transcription factor encoding a LytR family response regulator controls the expression of enterococcal polysaccharide antigen (epa) genes that are involved in phage infection and bacterial fitness. In addition, we discovered that DNA mismatch repair mutants rapidly evolve phage adsorption deficiencies, underpinning a molecular basis for epa mutation during phage infection. Transcriptomic profiling of phage-infected E. faecalis revealed broad transcriptional changes influencing viral replication and progeny burst size. We also demonstrate that phage infection alters the expression of bacterial genes associated with intra- and interbacterial interactions, including genes involved in quorum sensing and polymicrobial competition. Together, our results suggest that phage predation has the potential to influence complex microbial behavior and may dictate how bacteria respond to external environmental stimuli. These responses could have collateral effects (positive or negative) on microbial communities, such as the host microbiota, during phage therapy.

IMPORTANCE We lack fundamental understanding of how phage infection influences bacterial gene expression and, consequently, how bacterial responses to phage infection affect the assembly of polymicrobial communities. Using parallel genomic approaches, we have discovered novel transcriptional regulators and metabolic genes that influence phage infection. The integration of whole-genome transcriptomic profiling during phage infection has revealed the differential regulation of genes important for group behaviors and polymicrobial interactions. Our work suggests that therapeutic phages could more broadly influence bacterial community composition outside their intended host targets.

ABSTRACT

Bacterial flagella are rotating nanomachines required for motility. Flagellar gene expression and protein secretion are coordinated for efficient flagellar biogenesis. Polar flagellates, unlike peritrichous bacteria, commonly order flagellar rod and hook gene transcription as a separate step after production of the MS ring, C ring, and flagellar type III secretion system (fT3SS) core proteins that form a competent fT3SS. Conserved regulatory mechanisms in diverse polar flagellates to create this polar flagellar transcriptional program have not been thoroughly assimilated. Using in silico and genetic analyses and our previous findings in Campylobacter jejuni as a foundation, we observed a large subset of Gram-negative bacteria with the FlhF/FlhG regulatory system for polar flagellation to possess flagellum-associated two-component signal transduction systems (TCSs). We present data supporting a general theme in polar flagellates whereby MS ring, rotor, and fT3SS proteins contribute to a regulatory checkpoint during polar flagellar biogenesis. We demonstrate that Vibrio cholerae and Pseudomonas aeruginosa require the formation of this regulatory checkpoint for the TCSs to directly activate subsequent rod and hook gene transcription, which are hallmarks of the polar flagellar transcriptional program. By reprogramming transcription in V. cholerae to more closely follow the peritrichous flagellar transcriptional program, we discovered a link between the polar flagellar transcription program and the activity of FlhF/FlhG flagellar biogenesis regulators in which the transcriptional program allows polar flagellates to continue to produce flagella for motility when FlhF or FlhG activity may be altered. Our findings integrate flagellar transcriptional and biogenesis regulatory processes involved in polar flagellation in many species.

IMPORTANCE Relative to peritrichous bacteria, polar flagellates possess regulatory systems that order flagellar gene transcription differently and produce flagella in specific numbers only at poles. How transcriptional and flagellar biogenesis regulatory systems are interlinked to promote the correct synthesis of polar flagella in diverse species has largely been unexplored. We found evidence for many Gram-negative polar flagellates encoding two-component signal transduction systems with activity linked to the formation of flagellar type III secretion systems to enable production of flagellar rod and hook proteins at a discrete, subsequent stage during flagellar assembly. This polar flagellar transcriptional program assists, in some manner, the FlhF/FlhG flagellar biogenesis regulatory system, which forms specific flagellation patterns in polar flagellates in maintaining flagellation and motility when activity of FlhF or FlhG might be altered. Our work provides insight into the multiple regulatory processes required for polar flagellation.

ABSTRACT

In Escherichia coli, the chemotaxis response regulator CheY-P binds to FliM, a component of the switch complex at the base of the bacterial flagellar motor, to modulate the direction of motor rotation. The bacterial flagellar motor is ultrasensitive to the concentration of unbound CheY-P in the cytoplasm. CheY-P binds to FliM molecules both in the cytoplasm and on the motor. As the concentration of FliM unavoidably varies from cell to cell, leading to a variation of unbound CheY-P concentration in the cytoplasm, this raises the question whether the flagellar motor is robust against this variation, that is, whether the rotational bias of the motor is more or less constant as the concentration of FliM varies. Here, we showed that the motor is robust against variations of the concentration of FliM. We identified adaptive remodeling of the motor as the mechanism for this robustness. As the level of FliM molecules changes, resulting in different amounts of the unbound CheY-P molecules, the motor adaptively changes the composition of its switch complex to compensate for this effect.

IMPORTANCE The bacterial flagellar motor is an ultrasensitive motor. Its output, the probability of the motor turning clockwise, depends sensitively on the occupancy of the protein FliM (a component on the switch complex of the motor) by the input CheY-P molecules. With a limited cellular pool of CheY-P molecules, cell-to-cell variation of the FliM level would lead to large unwanted variation of the motor output if not compensated. Here, we showed that the motor output is robust against the variation of FliM level and identified the adaptive remodeling of the motor switch complex as the mechanism for this robustness.

ABSTRACT

In the absence of a vaccine, multidrug-resistant Neisseria gonorrhoeae has emerged as a major human health threat, and new approaches to treat gonorrhea are urgently needed. N. gonorrhoeae pili are posttranslationally modified by a glycan that terminates in a galactose. The terminal galactose is critical for initial contact with the human cervical mucosa via an interaction with the I-domain of complement receptor 3 (CR3). We have now identified the I-domain galactose-binding epitope and characterized its galactose-specific lectin activity. Using surface plasmon resonance and cellular infection assays, we found that a peptide mimic of this galactose-binding region competitively inhibited the N. gonorrhoeae-CR3 interaction. A compound library was screened for potential drugs that could similarly prohibit the N. gonorrhoeae-CR3 interaction and be repurposed as novel host-targeted therapeutics for multidrug-resistant gonococcal infections in women. Two drugs, methyldopa and carbamazepine, prevented and cured cervical cell infection by multidrug-resistant gonococci by blocking the gonococcal-CR3 I-domain interaction.

IMPORTANCE Novel therapies that avert the problem of Neisseria gonorrhoeae with acquired antibiotic resistance are urgently needed. Gonococcal infection of the human cervix is initiated by an interaction between a galactose modification made to its surface appendages, pili, and the I-domain region of (host) complement receptor 3 (CR3). By targeting this crucial gonococcal–I-domain interaction, it may be possible to prevent cervical infection in females. To this end, we identified the I-domain galactose-binding epitope of CR3 and characterized its galactose lectin activity. Moreover, we identified two drugs, carbamazepine and methyldopa, as effective host-targeted therapies for gonorrhea treatment. At doses below those currently used for their respective existing indications, both carbamazepine and methyldopa were more effective than ceftriaxone in curing cervical infection ex vivo. This host-targeted approach would not be subject to N. gonorrhoeae drug resistance mechanisms. Thus, our data suggest a long-term solution to the growing problem of multidrug-resistant N. gonorrhoeae infections.

ABSTRACT

Transporters belonging to the chromosomally encoded resistance-nodulation-division (RND) superfamily mediate multidrug resistance in Gram-negative bacteria. However, the cotransfer of large gene clusters encoding RND-type pumps from the chromosome to a plasmid appears infrequent, and no plasmid-mediated RND efflux pump gene cluster has yet been found to confer resistance to tigecycline. Here, we identified a novel RND efflux pump gene cluster, designated tmexCD1-toprJ1, on plasmids from five pandrug-resistant Klebsiella pneumoniae isolates of animal origin. TMexCD1-TOprJ1 increased (by 4- to 32-fold) the MICs of tetracyclines (including tigecycline and eravacycline), quinolones, cephalosporins, and aminoglycosides for K. pneumoniae, Escherichia coli, and Salmonella. TMexCD1-TOprJ1 is closely related (64.5% to 77.8% amino acid identity) to the MexCD-OprJ efflux pump encoded on the chromosome of Pseudomonas aeruginosa. In an IncFIA plasmid, pHNAH8I, the tmexCD1-toprJ1 gene cluster lies adjacent to two genes encoding site-specific integrases, which may have been responsible for its acquisition. Expression of TMexCD1-TOprJ1 in E. coli resulted in increased tigecycline efflux and in K. pneumoniae negated the efficacy of tigecycline in an in vivo infection model. Expression of TMexCD1-TOprJ1 reduced the growth of E. coli and Salmonella but not K. pneumoniae. tmexCD1-toprJ1-positive Enterobacteriaceae isolates were rare in humans (0.08%) but more common in chicken fecal (14.3%) and retail meat (3.4%) samples. Plasmid-borne tmexCD1-toprJ1-like gene clusters were identified in sequences in GenBank from Enterobacteriaceae and Pseudomonas strains from multiple continents. The possibility of further global dissemination of the tmexCD1-toprJ1 gene cluster and its analogues in Enterobacteriaceae via plasmids may be an important consideration for public health planning.

IMPORTANCE In an era of increasing concerns about antimicrobial resistance, tigecycline is likely to have a critically important role in the treatment of carbapenem-resistant Enterobacteriaceae, the most problematic pathogens in human clinical settings—especially carbapenem-resistant K. pneumoniae. Here, we identified a new plasmid-borne RND-type tigecycline resistance determinant, TMexCD1-TOprJ1, which is widespread among K. pneumoniae isolates from food animals. tmexCD1-toprJ1 appears to have originated from the chromosome of a Pseudomonas species and may have been transferred onto plasmids by adjacent site-specific integrases. Although tmexCD1-toprJ1 still appears to be rare in human clinical isolates, considering the transferability of the tmexCD1-toprJ1 gene cluster and the broad substrate spectrum of TMexCD1-TOprJ1, further dissemination of this mobile tigecycline resistance determinant is possible. Therefore, from a "One Health" perspective, measures are urgently needed to monitor and control its further spread. The current low prevalence in human clinical isolates provides a precious time window to design and implement measures to tackle this.