ot Efficacy and safety of two doses of budesonide/formoterol fumarate metered dose inhaler in COPD By openres.ersjournals.com Published On :: 2020-04-27T00:30:10-07:00 Inhaled corticosteroid/long-acting β2-agonist combination therapy is a recommended treatment option for patients with chronic obstructive pulmonary disease (COPD) and increased exacerbation risk, particularly those with elevated blood eosinophil levels. SOPHOS (NCT02727660) evaluated the efficacy and safety of two doses of budesonide/formoterol fumarate dihydrate metered dose inhaler (BFF MDI) versus formoterol fumarate dihydrate (FF) MDI, each delivered using co-suspension delivery technology, in patients with moderate-to-very severe COPD and a history of exacerbations. In this phase 3, randomised, double-blind, parallel-group, 12–52-week, variable length study, patients received twice-daily BFF MDI 320/10 µg or 160/10 µg, or FF MDI 10 µg. The primary endpoint was change from baseline in morning pre-dose trough forced expiratory volume in 1 s (FEV1) at week 12. Secondary and other endpoints included assessments of moderate/severe COPD exacerbations and safety. The primary analysis (modified intent-to-treat) population included 1843 patients (BFF MDI 320/10 µg, n=619; BFF MDI 160/10 µg, n=617; and FF MDI, n=607). BFF MDI 320/10 µg and 160/10 µg improved morning pre-dose trough FEV1 at week 12 versus FF MDI (least squares mean differences 34 mL [p=0.0081] and 32 mL [p=0.0134], respectively), increased time to first exacerbation (hazard ratios 0.827 [p=0.0441] and 0.803 [p=0.0198], respectively) and reduced exacerbation rate (rate ratios 0.67 [p=0.0001] and 0.71 [p=0.0010], respectively). Lung function and exacerbation benefits were driven by patients with blood eosinophil counts ≥150 cells·mm–3. The incidence of adverse events was similar, and pneumonia rates were low (≤2.4%) across treatments. SOPHOS demonstrated the efficacy and tolerability of BFF MDI 320/10 µg and 160/10 µg in patients with moderate-to-very severe COPD at increased risk of exacerbations. Full Article
ot A microsimulation model to assess the economic impact of immunotherapy in non-small cell lung cancer By openres.ersjournals.com Published On :: 2020-04-19T07:30:12-07:00 Introduction Immunotherapy has become the standard of care in advanced non-small cell lung cancer (NSCLC). We aimed to quantify the economic impact, in France, of anti-PD-1 therapy for NSCLC. Methods We used patient-level data from the national ESCAP-2011-CPHG cohort study to estimate time to treatment failure and mean cost per patient for the four label indications approved by the European Medicines Agency (EMA) for NSCLC in May 2018. To compute the budget impact, we used a microsimulation model to estimate the target populations of anti-PD-1 therapy over a 3-year period, which were combined with the annual cost of treatment. Results Overall, 11 839 patients with NSCLC were estimated to be eligible for anti-PD-1 therapy 3 years after the introduction of anti-PD-1 therapies. The mean annual cost per patient in the control group ranged from 2671 (95% CI 2149–3194) to 6412 (95% CI 5920–6903) across the four indications. The mean annual cost of treatment for the four EMA-approved indications of anti-PD-1 therapy was estimated to be 48.7 million in the control group and at 421.8 million in the immunotherapy group. The overall budget impact in 2019 is expected to amount to 373.1 million. In the sensitivity analysis, flat doses and treatment effect had the greatest influence on the budget impact. Conclusion Anti-PD-1 agents for NSCLC treatment are associated with a substantial economic burden. Full Article
ot Genetic Association Reveals Protection against Recurrence of Clostridium difficile Infection with Bezlotoxumab Treatment By msphere.asm.org Published On :: 2020-05-06T07:29:31-07:00 ABSTRACT Bezlotoxumab is a human monoclonal antibody against Clostridium difficile toxin B, indicated to prevent recurrence of C. difficile infection (rCDI) in high-risk adults receiving antibacterial treatment for CDI. An exploratory genome-wide association study investigated whether human genetic variation influences bezlotoxumab response. DNA from 704 participants who achieved initial clinical cure in the phase 3 MODIFY I/II trials was genotyped. Single nucleotide polymorphisms (SNPs) and human leukocyte antigen (HLA) imputation were performed using IMPUTE2 and HIBAG, respectively. A joint test of genotype and genotype-by-treatment interaction in a logistic regression model was used to screen genetic variants associated with response to bezlotoxumab. The SNP rs2516513 and the HLA alleles HLA-DRB1*07:01 and HLA-DQA1*02:01, located in the extended major histocompatibility complex on chromosome 6, were associated with the reduction of rCDI in bezlotoxumab-treated participants. Carriage of a minor allele (homozygous or heterozygous) at any of the identified loci was related to a larger difference in the proportion of participants experiencing rCDI versus placebo; the effect was most prominent in the subgroup at high baseline risk for rCDI. Genotypes associated with an improved bezlotoxumab response showed no association with rCDI in the placebo cohort. These data suggest that a host-driven, immunological mechanism may impact bezlotoxumab response. Trial registration numbers are as follows: NCT01241552 (MODIFY I) and NCT01513239 (MODIFY II). IMPORTANCE Clostridium difficile infection is associated with significant clinical morbidity and mortality; antibacterial treatments are effective, but recurrence of C. difficile infection is common. In this genome-wide association study, we explored whether host genetic variability affected treatment responses to bezlotoxumab, a human monoclonal antibody that binds C. difficile toxin B and is indicated for the prevention of recurrent C. difficile infection. Using data from the MODIFY I/II phase 3 clinical trials, we identified three genetic variants associated with reduced rates of C. difficile infection recurrence in bezlotoxumab-treated participants. The effects were most pronounced in participants at high risk of C. difficile infection recurrence. All three variants are located in the extended major histocompatibility complex on chromosome 6, suggesting the involvement of a host-driven immunological mechanism in the prevention of C. difficile infection recurrence. Full Article
ot Lack of Evidence for Microbiota in the Placental and Fetal Tissues of Rhesus Macaques By msphere.asm.org Published On :: 2020-05-06T07:29:31-07:00 ABSTRACT The prevailing paradigm in obstetrics has been the sterile womb hypothesis. However, some are asserting that the placenta, intra-amniotic environment, and fetus harbor microbial communities. The objective of this study was to determine whether the fetal and placental tissues of rhesus macaques harbor bacterial communities. Fetal, placental, and uterine wall samples were obtained from cesarean deliveries without labor (~130/166 days gestation). The presence of bacteria in the fetal intestine and placenta was investigated through culture. The bacterial burden and profiles of the placenta, umbilical cord, and fetal brain, heart, liver, and colon were determined through quantitative real-time PCR and DNA sequencing. These data were compared with those of the uterine wall as well as to negative and positive technical controls. Bacterial cultures of fetal and placental tissues yielded only a single colony of Cutibacterium acnes. This bacterium was detected at a low relative abundance (0.02%) in the 16S rRNA gene profile of the villous tree sample from which it was cultured, yet it was also identified in 12/29 background technical controls. The bacterial burden and profiles of fetal and placental tissues did not exceed or differ from those of background technical controls. By contrast, the bacterial burden and profiles of positive controls exceeded and differed from those of background controls. Among the macaque samples, distinct microbial signals were limited to the uterine wall. Therefore, using multiple modes of microbiologic inquiry, there was not consistent evidence of bacterial communities in the fetal and placental tissues of rhesus macaques. IMPORTANCE Microbial invasion of the amniotic cavity (i.e., intra-amniotic infection) has been causally linked to pregnancy complications, especially preterm birth. Therefore, if the placenta and the fetus are typically populated by low-biomass microbial communities, current understanding of the role of microbes in reproduction and pregnancy outcomes will need to be fundamentally reconsidered. Could these communities be of benefit by competitively excluding potential pathogens or priming the fetal immune system for the microbial bombardment it will experience upon delivery? If so, what properties (e.g., microbial load and community membership) of these microbial communities preclude versus promote intra-amniotic infection? Given the ramifications of the in utero colonization hypothesis, critical evaluation is required. In this study, using multiple modes of microbiologic inquiry (i.e., culture, quantitative real-time PCR [qPCR], and DNA sequencing) and controlling for potential background DNA contamination, we did not find consistent evidence for microbial communities in the placental and fetal tissues of rhesus macaques. Full Article
ot Subtle Variations in Dietary-Fiber Fine Structure Differentially Influence the Composition and Metabolic Function of Gut Microbiota By msphere.asm.org Published On :: 2020-05-06T07:29:31-07:00 ABSTRACT The chemical structures of soluble fiber carbohydrates vary from source to source due to numerous possible linkage configurations among monomers. However, it has not been elucidated whether subtle structural variations might impact soluble fiber fermentation by colonic microbiota. In this study, we tested the hypothesis that subtle structural variations in a soluble polysaccharide govern the community structure and metabolic output of fermenting microbiota. We performed in vitro fecal fermentation studies using arabinoxylans (AXs) from different classes of wheat (hard red spring [AXHRS], hard red winter [AXHRW], and spring red winter [AXSRW]) with identical initial microbiota. Carbohydrate analyses revealed that AXSRW was characterized by a significantly shorter backbone and increased branching compared with those of the hard varieties. Amplicon sequencing demonstrated that fermentation of AXSRW resulted in a distinct community structure of significantly higher richness and evenness than those of hard-AX-fermenting cultures. AXSRW favored OTUs within Bacteroides, whereas AXHRW and AXHRS favored Prevotella. Accordingly, metabolic output varied between hard and soft varieties; higher propionate production was observed with AXSRW and higher butyrate and acetate with AXHRW and AXHRS. This study showed that subtle changes in the structure of a dietary fiber may strongly influence the composition and function of colonic microbiota, further suggesting that physiological functions of dietary fibers are highly structure dependent. Thus, studies focusing on interactions among dietary fiber, gut microbiota, and health outcomes should better characterize the structures of the carbohydrates employed. IMPORTANCE Diet, especially with respect to consumption of dietary fibers, is well recognized as one of the most important factors shaping the colonic microbiota composition. Accordingly, many studies have been conducted to explore dietary fiber types that could predictably manipulate the colonic microbiota for improved health. However, the majority of these studies underappreciate the vastness of fiber structures in terms of their microbial utilization and omit detailed carbohydrate structural analysis. In some cases, this causes conflicting results to arise between studies using (theoretically) the same fibers. In this investigation, by performing in vitro fecal fermentation studies using bran arabinoxylans obtained from different classes of wheat, we showed that even subtle changes in the structure of a dietary fiber result in divergent microbial communities and metabolic outputs. This underscores the need for much higher structural resolution in studies investigating interactions of dietary fibers with gut microbiota, both in vitro and in vivo. Full Article
ot Advances in the use of isotopes in geochemical exploration: instrumentation and applications in understanding geochemical processes By geea.lyellcollection.org Published On :: 2020-05-01T00:30:32-07:00 Among the emerging techniques to detect the real footprint of buried ore deposits is isotope tracing. Novel and automated preparation systems such as continuous flow isotope ratio mass spectrometry, off-axis integrated cavity output spectroscopy for isotopic compositions of selected molecules, multi-collector inductively coupled-plasma mass spectrometry (ICP-MS), triple quadrupole ICP-MS, laser ablation ICP-MS, and a multitude of inline preparation systems have facilitated the use of isotopes as tracers in mineral exploration, as costs for isotope analyses have decreased and the time required for the analyses has improved. In addition, the isotope systems being used have expanded beyond the traditional light stable and Pb isotopes to include a multitude of elements that behave differently during processes that promote the mobilization of elements during both primary and secondary dispersion. Isotopes are also being used to understand barren areas that lack a critical process to form an ore deposit and to reveal precise redox mechanisms. The goal is to be able to use isotopes to reflect a definitive process that occurs in association with the deposit and not in barren systems, and then to relate these to something that is easier to measure, namely elemental concentrations. As new generations of exploration and environmental scientists are becoming more comfortable with the application of isotopes to effectively trace processes involved in geoscience, and new technologies for rapid and inexpensive analyses of isotopes are continually being developed, novel applications of isotope tracing are becoming more mainstream. Thematic collection: This article is part of the Exploration 17 collection available at: https://www.lyellcollection.org/cc/exploration-17 Full Article
ot Recent advances in the application of mineral chemistry to exploration for porphyry copper-gold-molybdenum deposits: detecting the geochemical fingerprints and footprints of hypogene mineralization and alteration By geea.lyellcollection.org Published On :: 2020-05-01T00:30:32-07:00 In the past decade, significant research efforts have been devoted to mineral chemistry studies to assist porphyry exploration. These activities can be divided into two major fields of research: (1) porphyry indicator minerals (PIMs), which are used to identify the presence of, or potential for, porphyry-style mineralization based on the chemistry of magmatic minerals such as zircon, plagioclase and apatite, or resistate hydrothermal minerals such as magnetite; and (2) porphyry vectoring and fertility tools (PVFTs), which use the chemical compositions of hydrothermal minerals such as epidote, chlorite and alunite to predict the likely direction and distance to mineralized centres, and the potential metal endowment of a mineral district. This new generation of exploration tools has been enabled by advances in and increased access to laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), short-wave length infrared (SWIR), visible near-infrared (VNIR) and hyperspectral technologies. PIMs and PVFTs show considerable promise for exploration and are starting to be applied to the diversity of environments that host porphyry and epithermal deposits globally. Industry has consistently supported development of these tools, and in the case of PVFTs encouraged by several successful blind tests where deposit centres have successfully been predicted from distal propylitic settings. Industry adoption is steadily increasing but is restrained by a lack of the necessary analytical equipment and expertise in commercial laboratories, and also by the ongoing reliance on well-established geochemical exploration techniques (e.g. sediment, soil and rock chip sampling) that have aided the discovery of near-surface resources over many decades, but are now proving less effective in the search for deeply buried mineral resources and for those concealed under cover. Thematic collection: This article is part of the Exploration 17 collection available at: https://www.lyellcollection.org/cc/exploration-17 Full Article
ot Microbiota-Propelled T Helper 17 Cells in Inflammatory Diseases and Cancer [Review] By mmbr.asm.org Published On :: 2020-03-04T05:30:12-08:00 Technologies allowing genetic sequencing of the human microbiome are opening new realms to discovery. The host microbiota substantially impacts immune responses both in immune-mediated inflammatory diseases (IMIDs) and in tumors affecting tissues beyond skin and mucosae. However, a mechanistic link between host microbiota and cancer or IMIDs has not been well established. Here, we propose T helper 17 (TH17) lymphocytes as the connecting factor between host microbiota and rheumatoid or psoriatic arthritides, multiple sclerosis, breast or ovarian cancer, and multiple myeloma. We theorize that similar mechanisms favor the expansion of gut-borne TH17 cells and their deployment at the site of inflammation in extraborder IMIDs and tumors, where TH17 cells are driving forces. Thus, from a pathogenic standpoint, tumors may share mechanistic routes with IMIDs. A review of similarities and divergences in microbiota-TH17 cell interactions in IMIDs and cancer sheds light on previously ignored pathways in either one of the two groups of pathologies and identifies novel therapeutic avenues. Full Article
ot Structural Biology of the Enterovirus Replication-Linked 5'-Cloverleaf RNA and Associated Virus Proteins [Review] By mmbr.asm.org Published On :: 2020-03-18T05:29:37-07:00 Although enteroviruses are associated with a wide variety of diseases and conditions, their mode of replication is well conserved. Their genome is carried as a single, positive-sense RNA strand. At the 5' end of the strand is an approximately 90-nucleotide self-complementary region called the 5' cloverleaf, or the oriL. This noncoding region serves as a platform upon which host and virus proteins, including the 3B, 3C, and 3D virus proteins, assemble in order to initiate replication of a negative-sense RNA strand. The negative strand in turn serves as a template for synthesis of multiple positive-sense RNA strands. Building on structural studies of individual RNA stem-loops, the structure of the intact 5' cloverleaf from rhinovirus has recently been determined via nuclear magnetic resonance/small-angle X-ray scattering (NMR/SAXS)-based methods, while structures have also been determined for enterovirus 3A, 3B, 3C, and 3D proteins. Analysis of these structures, together with structural and modeling studies of interactions between host and virus proteins and RNA, has begun to provide insight into the enterovirus replication mechanism and the potential to inhibit replication by blocking these interactions. Full Article
ot Bioavailability Based on the Gut Microbiota: a New Perspective [Review] By mmbr.asm.org Published On :: 2020-04-29T05:30:12-07:00 The substantial discrepancy between the strong effects of functional foods and various drugs, especially traditional Chinese medicines (TCMs), and the poor bioavailability of these substances remains a perplexing problem. Understanding the gut microbiota, which acts as an effective bioreactor in the human intestinal tract, provides an opportunity for the redefinition of bioavailability. Here, we discuss four different pathways associated with the role of the gut microbiota in the transformation of parent compounds to beneficial or detrimental small molecules, which can enter the body’s circulatory system and be available to target cells, tissues, and organs. We further describe and propose effective strategies for improving bioavailability and alleviating side effects with the help of the gut microbiota. This review also broadens our perspectives for the discovery of new medicinal components. Full Article
ot Posttranscriptional Regulation of tnaA by Protein-RNA Interaction Mediated by Ribosomal Protein L4 in Escherichia coli [Article] By jb.asm.org Published On :: 2020-04-27T08:00:23-07:00 Escherichia coli ribosomal protein (r-protein) L4 has extraribosomal biological functions. Previously, we described L4 as inhibiting RNase E activity through protein-protein interactions. Here, we report that from stabilized transcripts regulated by L4-RNase E, mRNA levels of tnaA (encoding tryptophanase from the tnaCAB operon) increased upon ectopic L4 expression, whereas TnaA protein levels decreased. However, at nonpermissive temperatures (to inactivate RNase E), tnaA mRNA and protein levels both increased in an rne temperature-sensitive [rne(Ts)] mutant strain. Thus, L4 protein fine-tunes TnaA protein levels independently of its inhibition of RNase E. We demonstrate that ectopically expressed L4 binds with transcribed spacer RNA between tnaC and tnaA and downregulates TnaA translation. We found that deletion of the 5' or 3' half of the spacer compared to the wild type resulted in a similar reduction in TnaA translation in the presence of L4. In vitro binding of L4 to the tnaC-tnaA transcribed spacer RNA results in changes to its secondary structure. We reveal that during early stationary-phase bacterial growth, steady-state levels of tnaA mRNA increased but TnaA protein levels decreased. We further confirm that endogenous L4 binds to tnaC-tnaA transcribed spacer RNA in cells at early stationary phase. Our results reveal the novel function of L4 in fine-tuning TnaA protein levels during cell growth and demonstrate that r-protein L4 acts as a translation regulator outside the ribosome and its own operon. IMPORTANCE Some ribosomal proteins have extraribosomal functions in addition to ribosome translation function. The extraribosomal functions of several r-proteins control operon expression by binding to own-operon transcripts. Previously, we discovered a posttranscriptional, RNase E-dependent regulatory role for r-protein L4 in the stabilization of stress-responsive transcripts. Here, we found an additional extraribosomal function for L4 in regulating the tna operon by L4-intergenic spacer mRNA interactions. L4 binds to the transcribed spacer RNA between tnaC and tnaA and alters the structural conformation of the spacer RNA, thereby reducing the translation of TnaA. Our study establishes a previously unknown L4-mediated mechanism for regulating gene expression, suggesting that bacterial cells have multiple strategies for controlling levels of tryptophanase in response to varied cell growth conditions. Full Article
ot Multiple and Overlapping Functions of Quorum Sensing Proteins for Cell Specialization in Bacillus Species [Minireviews] By jb.asm.org Published On :: 2020-04-27T08:00:23-07:00 In bacterial populations, quorum sensing (QS) systems participate in the regulation of specialization processes and regulate collective behaviors that mediate interactions and allow survival of the species. In Gram-positive bacteria, QS systems of the RRNPP family (Rgg, Rap, NprR, PlcR, and PrgX) consist of intracellular receptors and their cognate signaling peptides. Two of these receptors, Rap and NprR, have regained attention in Bacillus subtilis and the Bacillus cereus group. Some Rap proteins, such as RapH and Rap60, are multifunctional and/or redundant in function, linking the specialization processes of sporulation and competence, as well as global expression changes in the transition phase in B. subtilis. NprR, an evolutionary intermediate between Rap and RRNPP transcriptional activators, is a bifunctional regulator that modulates sporulation initiation and activates nutrient scavenging genes. In this review, we discuss how these receptors switch between functions and connect distinct signaling pathways. Based on structural evidence, we propose that RapH and Rap60 should be considered moonlighting proteins. Additionally, we analyze an evolutionary and ecological perspective to understand the multifunctionality and functional redundancy of these regulators in both Bacillus spp. and non-Bacillus Firmicutes. Understanding the mechanistic, structural, ecological, and evolutionary basis for the multifunctionality and redundancy of these QS systems is a key step for achieving the development of innovative technologies for health and agriculture. Full Article
ot Articles of Significant Interest in This Issue [Spotlight] By jb.asm.org Published On :: 2020-04-27T08:00:23-07:00 Full Article
ot The M Protein of Streptococcus pyogenes Strain AP53 Retains Cell Surface Functional Plasminogen Binding after Inactivation of the Sortase A Gene [Article] By jb.asm.org Published On :: 2020-04-27T08:00:23-07:00 Streptococcus pyogenes (Lancefield group A Streptococcus [GAS]) is a β-hemolytic human-selective pathogen that is responsible for a large number of morbid and mortal infections in humans. For efficient infection, GAS requires different types of surface proteins that provide various mechanisms for evading human innate immune responses, thus enhancing pathogenicity of the bacteria. Many such virulence-promoting proteins, including the major surface signature M protein, are translocated after biosynthesis through the cytoplasmic membrane and temporarily tethered to this membrane via a type 1 transmembrane domain (TMD) positioned near the COOH terminus. In these proteins, a sorting signal, LPXTG, is positioned immediately upstream of the TMD, which is cleaved by the membrane-associated transpeptidase, sortase A (SrtA), leading to the covalent anchoring of these proteins to newly emerging l-Ala–l-Ala cross-bridges of the growing peptidoglycan cell wall. Herein, we show that inactivation of the srtA gene in a skin-tropic pattern D GAS strain (AP53) results in retention of the M protein in the cell membrane. However, while the isogenic AP53 srtA strain is attenuated in overall pathogenic properties due to effects on the integrity of the cell membrane, our data show that the M protein nonetheless can extend from the cytoplasmic membrane through the cell wall and then to the surface of the bacteria and thereby retain its important properties of productively binding and activating fluid-phase host plasminogen (hPg). The studies presented herein demonstrate an underappreciated additional mechanism of cell surface display of bacterial virulence proteins via their retention in the cell membrane and extension to the GAS surface. IMPORTANCE Group A Streptococcus pyogenes (GAS) is a human-specific pathogen that produces many surface factors, including its signature M protein, that contribute to its pathogenicity. M proteins undergo specific membrane localization and anchoring to the cell wall via the transpeptidase sortase A. Herein, we explored the role of sortase A function on M protein localization, architecture, and function, employing, a skin-tropic GAS isolate, AP53, which expresses a human plasminogen (hPg)-binding M (PAM) Protein. We showed that PAM anchored in the cell membrane, due to the targeted inactivation of sortase A, was nonetheless exposed on the cell surface and functionally interacted with host hPg. We demonstrate that M proteins, and possibly other sortase A-processed proteins that are retained in the cell membrane, can still function to initiate pathogenic processes by this underappreciated mechanism. Full Article
ot Fur-Dam Regulatory Interplay at an Internal Promoter of the Enteroaggregative Escherichia coli Type VI Secretion sci1 Gene Cluster [Article] By jb.asm.org Published On :: 2020-04-27T08:00:23-07:00 The type VI secretion system (T6SS) is a weapon for delivering effectors into target cells that is widespread in Gram-negative bacteria. The T6SS is a highly versatile machine, as it can target both eukaryotic and prokaryotic cells, and it has been proposed that T6SSs are adapted to the specific needs of each bacterium. The expression of T6SS gene clusters and the activation of the secretion apparatus are therefore tightly controlled. In enteroaggregative Escherichia coli (EAEC), the sci1 T6SS gene cluster is subject to a complex regulation involving both the ferric uptake regulator (Fur) and DNA adenine methylase (Dam)-dependent DNA methylation. In this study, an additional, internal, promoter was identified within the sci1 gene cluster using +1 transcriptional mapping. Further analyses demonstrated that this internal promoter is controlled by a mechanism strictly identical to that of the main promoter. The Fur binding box overlaps the –10 transcriptional element and a Dam methylation site, GATC-32. Hence, the expression of the distal sci1 genes is repressed and the GATC-32 site is protected from methylation in iron-rich conditions. The Fur-dependent protection of GATC-32 was confirmed by an in vitro methylation assay. In addition, the methylation of GATC-32 negatively impacted Fur binding. The expression of the sci1 internal promoter is therefore controlled by iron availability through Fur regulation, whereas Dam-dependent methylation maintains a stable ON expression in iron-limited conditions. IMPORTANCE Bacteria use weapons to deliver effectors into target cells. One of these weapons, the type VI secretion system (T6SS), assembles a contractile tail acting as a spring to propel a toxin-loaded needle. Its expression and activation therefore need to be tightly regulated. Here, we identified an internal promoter within the sci1 T6SS gene cluster in enteroaggregative E. coli. We show that this internal promoter is controlled by Fur and Dam-dependent methylation. We further demonstrate that Fur and Dam compete at the –10 transcriptional element to finely tune the expression of T6SS genes. We propose that this elegant regulatory mechanism allows the optimum production of the T6SS in conditions where enteroaggregative E. coli encounters competing species. Full Article
ot The Antiactivator of Type III Secretion, OspD1, Is Transcriptionally Regulated by VirB and H-NS from Remote Sequences in Shigella flexneri [Article] By jb.asm.org Published On :: 2020-04-27T08:00:23-07:00 Shigella species, the causal agents of bacillary dysentery, use a type III secretion system (T3SS) to inject two waves of virulence proteins, known as effectors, into the colonic epithelium to subvert host cell machinery. Prior to host cell contact and secretion of the first wave of T3SS effectors, OspD1, an effector and antiactivator protein, prevents premature production of the second wave of effectors. Despite this important role, regulation of the ospD1 gene is not well understood. While ospD1 belongs to the large regulon of VirB, a transcriptional antisilencing protein that counters silencing mediated by the histone-like nucleoid structuring protein H-NS, it remains unclear if VirB directly or indirectly regulates ospD1. Additionally, it is not known if ospD1 is regulated by H-NS. Here, we identify the primary ospD1 transcription start site (+1) and show that the ospD1 promoter is remotely regulated by both VirB and H-NS. Our findings demonstrate that VirB regulation of ospD1 requires at least one of the two newly identified VirB regulatory sites, centered at –978 and –1270 relative to the ospD1 +1. Intriguingly, one of these sites lies on a 193-bp sequence found in three conserved locations on the large virulence plasmids of Shigella. The region required for H-NS-dependent silencing of ospD1 lies between –1120 and –820 relative to the ospD1 +1. Thus, our study provides further evidence that cis-acting regulatory sequences for transcriptional antisilencers and silencers, such as VirB and H-NS, can lie far upstream of the canonical bacterial promoter region (i.e., –250 to +1). IMPORTANCE Transcriptional silencing and antisilencing mechanisms regulate virulence gene expression in many important bacterial pathogens. In Shigella species, plasmid-borne virulence genes, such as those encoding the type III secretion system (T3SS), are silenced by the histone-like nucleoid structuring protein H-NS and antisilenced by VirB. Previous work at the plasmid-borne icsP locus revealed that VirB binds to a remotely located cis-acting regulatory site to relieve transcriptional silencing mediated by H-NS. Here, we characterize a second example of remote VirB antisilencing at ospD1, which encodes a T3SS antiactivator and effector. Our study highlights that remote transcriptional silencing and antisilencing occur more frequently in Shigella than previously thought, and it raises the possibility that long-range transcriptional regulation in bacteria is commonplace. Full Article
ot Ribosome Dimerization Protects the Small Subunit [Article] By jb.asm.org Published On :: 2020-04-27T08:00:23-07:00 When nutrients become scarce, bacteria can enter an extended state of quiescence. A major challenge of this state is how to preserve ribosomes for the return to favorable conditions. Here, we show that the ribosome dimerization protein hibernation-promoting factor (HPF) functions to protect essential ribosomal proteins. Ribosomes isolated from strains lacking HPF (hpf) or encoding a mutant allele of HPF that binds the ribosome but does not mediate dimerization were substantially depleted of the small subunit proteins S2 and S3. Strikingly, these proteins are located directly at the ribosome dimer interface. We used single-particle cryo-electron microscopy (cryo-EM) to further characterize these ribosomes and observed that a high percentage of ribosomes were missing S2, S3, or both. These data support a model in which the ribosome dimerization activity of HPF evolved to protect labile proteins that are essential for ribosome function. HPF is almost universally conserved in bacteria, and HPF deletions in diverse species exhibit decreased viability during starvation. Our data provide mechanistic insight into this phenotype and establish a mechanism for how HPF protects ribosomes during quiescence. IMPORTANCE The formation of ribosome dimers during periods of dormancy is widespread among bacteria. Dimerization is typically mediated by a single protein, hibernation-promoting factor (HPF). Bacteria lacking HPF exhibit strong defects in viability and pathogenesis and, in some species, extreme loss of rRNA. The mechanistic basis of these phenotypes has not been determined. Here, we report that HPF from the Gram-positive bacterium Bacillus subtilis preserves ribosomes by preventing the loss of essential ribosomal proteins at the dimer interface. This protection may explain phenotypes associated with the loss of HPF, since ribosome protection would aid survival during nutrient limitation and impart a strong selective advantage when the bacterial cell rapidly reinitiates growth in the presence of sufficient nutrients. Full Article
ot Chitotriosidase: a marker and modulator of lung disease By err.ersjournals.com Published On :: 2020-04-29T01:39:43-07:00 Chitotriosidase (CHIT1) is a highly conserved and regulated chitinase secreted by activated macrophages; it is a member of the 18-glycosylase family (GH18). CHIT1 is the most prominent chitinase in humans, can cleave chitin and participates in the body's immune response and is associated with inflammation, infection, tissue damage and remodelling processes. Recently, CHIT1 has been reported to be involved in the molecular pathogenesis of pulmonary fibrosis, bronchial asthma, COPD and pulmonary infections, shedding new light on the role of these proteins in lung pathophysiology. The potential roles of CHIT1 in lung diseases are reviewed in this article. Full Article
ot Both Prediabetes and Type 2 Diabetes Are Associated With Lower Heart Rate Variability: The Maastricht Study By care.diabetesjournals.org Published On :: 2020-04-20T12:00:33-07:00 OBJECTIVE Low heart rate variability (HRV), a marker for cardiac autonomic dysfunction, is a known feature of type 2 diabetes, but it remains incompletely understood whether this also applies to prediabetes or across the whole glycemic spectrum. Therefore, we investigated the association among prediabetes, type 2 diabetes, and measures of glycemia and HRV. RESEARCH DESIGN AND METHODS In the population-based Maastricht Study (n = 2,107; mean ± SD age 59 ± 8 years; 52% men; normal glucose metabolism [n = 1,226], prediabetes [n = 331], and type 2 diabetes [n = 550, oversampled]), we determined 24-h electrocardiogram-derived HRV in time and frequency domains (individual z-scores, based upon seven and six variables, respectively). We used linear regression with adjustments for age, sex, and major cardiovascular risk factors. RESULTS After adjustments, both time and frequency domain HRV were lower in prediabetes and type 2 diabetes as compared with normal glucose metabolism (standardized β [95% CI] for time domain: –0.15 [–0.27; –0.03] and –0.34 [–0.46; –0.22], respectively, P for trend <0.001; for frequency domain: –0.14 [–0.26; –0.02] and –0.31 [–0.43; –0.19], respectively, P for trend <0.001). In addition, 1-SD higher glycated hemoglobin, fasting plasma glucose, and 2-h postload glucose were associated with lower HRV in both domains (time domain: –0.16 [–0.21; –0.12], –0.16 [–0.21; –0.12], and –0.15 [–0.20; –0.10], respectively; frequency domain: –0.14 [–0.19; –0.10], –0.14 [–0.18; –0.09], and –0.13 [–0.18; –0.08], respectively). CONCLUSIONS Both prediabetes and type 2 diabetes were independently associated with lower HRV. This is further substantiated by independent continuous associations between measures of hyperglycemia and lower HRV. These data strongly suggest that cardiac autonomic dysfunction is already present in prediabetes. Full Article
ot The Prognosis of Patients With Type 2 Diabetes and Nonalbuminuric Diabetic Kidney Disease Is Not Always Poor: Implication of the Effects of Coexisting Macrovascular Complications (JDDM 54) By care.diabetesjournals.org Published On :: 2020-04-20T12:00:33-07:00 OBJECTIVE Nonalbuminuric diabetic kidney disease (DKD) has become the prevailing phenotype in patients with type 2 diabetes. However, it remains unclear whether its prognosis is poorer than that of other DKD phenotypes. RESEARCH DESIGN AND METHODS A total of 2,953 Japanese patients with type 2 diabetes and estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m2, enrolled in an observational cohort study in 2004, were followed until 2015. On the basis of albuminuria (>30 mg/g creatinine) and reduced eGFR (<60 mL/min/1.73 m2) at baseline, participants were classified into the four DKD phenotypes—no-DKD, albuminuric DKD without reduced eGFR, nonalbuminuric DKD with reduced eGFR, and albuminuric DKD with reduced eGFR—to assess the risks of mortality, cardiovascular disease (CVD), and renal function decline. RESULTS During the mean follow-up of 9.7 years, 113 patients died and 263 developed CVD. In nonalbuminuric DKD, the risks of death or CVD were not higher than those in no-DKD (adjusted hazard ratio 1.02 [95% CI 0.66, 1.60]) and the annual decline in eGFR was slower than in other DKD phenotypes. The risks of death or CVD in nonalbuminuric DKD without prior CVD were similar to those in no-DKD without prior CVD, whereas the risks in nonalbuminuric DKD with prior CVD as well as other DKD phenotypes were higher. CONCLUSIONS Nonalbuminuric DKD did not have a higher risk of mortality, CVD events, or renal function decline than the other DKD phenotypes. In nonalbuminuric DKD, the presence of macrovascular complications may be a main determinant of prognosis rather than the renal phenotype. Full Article
ot Early Childhood Antibiotic Treatment for Otitis Media and Other Respiratory Tract Infections Is Associated With Risk of Type 1 Diabetes: A Nationwide Register-Based Study With Sibling Analysis By care.diabetesjournals.org Published On :: 2020-04-20T12:00:32-07:00 OBJECTIVE The effect of early-life antibiotic treatment on the risk of type 1 diabetes is debated. This study assessed this question, applying a register-based design in children up to age 10 years including a large sibling-control analysis. RESEARCH DESIGN AND METHODS All singleton children (n = 797,318) born in Sweden between 1 July 2005 and 30 September 2013 were included and monitored to 31 December 2014. Cox proportional hazards models, adjusted for parental and perinatal characteristics, were applied, and stratified models were used to account for unmeasured confounders shared by siblings. RESULTS Type 1 diabetes developed in 1,297 children during the follow-up (median 4.0 years [range 0–8.3]). Prescribed antibiotics in the 1st year of life (23.8%) were associated with an increased risk of type 1 diabetes (adjusted hazard ratio [HR] 1.19 [95% CI 1.05–1.36]), with larger effect estimates among children delivered by cesarean section (P for interaction = 0.016). The association was driven by exposure to antibiotics primarily used for acute otitis media and respiratory tract infections. Further, we found an association of antibiotic prescriptions in pregnancy (22.5%) with type 1 diabetes (adjusted HR 1.15 [95% CI 1.00–1.32]). In general, sibling analysis supported these results, albeit often with statistically nonsignificant associations. CONCLUSIONS Dispensed prescription of antibiotics, mainly for acute otitis media and respiratory tract infections, in the 1st year of life is associated with an increased risk of type 1 diabetes before age 10 years, most prominently in children delivered by cesarean section. Full Article
ot Associations Between Racial and Ethnic Groups and Foot Self-Inspection in People With Diabetes By care.diabetesjournals.org Published On :: 2020-04-20T12:00:32-07:00 OBJECTIVE Daily foot self-inspection may permit earlier detection and treatment of a foot lesion, reducing the risk of infection and lower-limb amputation (LLA). Though race and ethnicity are strongly associated with LLA risk, with higher risk seen in African Americans (AA), American Indians/Alaska Natives (AI/AN), and Native Hawaiians/Pacific Islanders (NH/PI), associations between foot self-inspection and racial and ethnic groups are inconsistent. We aimed to assess differences in foot self-inspection among people with diabetes by race/ethnicity. RESEARCH DESIGN AND METHODS Using national, cross-sectional data from the 2015–2017 Behavioral Risk Factor Surveillance System surveys and including 88,424 individuals with diabetes, we estimated prevalence ratios (PRs) and associated 95% CIs of daily foot checking for sores or irritation by racial and ethnic groups using log-binomial linear regression models, after accounting for survey weights. RESULTS Compared with whites (who had a weighted prevalence [P] of daily foot self-inspection of 57%), AA (P 67%, PR 1.18 [95% CI 1.14, 1.23]), AI/AN (P 66%, PR 1.15 [95% CI 1.07, 1.25]), and NH/PI (P 71%, PR 1.25 [95% CI 1.03, 1.52]) had higher prevalences of daily foot self-inspection. The prevalence of daily foot inspection was significantly lower among Asians (P 35%, PR 0.62 [95% CI 0.48, 0.81]) and Hispanics (P 53%, PR 0.93 [95% CI 0.88, 0.99]) compared with whites. Associations did not vary importantly by insulin use, years since diabetes diagnosis, or having received diabetes self-management education. CONCLUSIONS The higher frequency of foot self-inspection in racial and ethnic groups at elevated risk of diabetes-related LLA is not sufficient to eliminate LLA disparities; additional interventions are needed to achieve this aim. Full Article
ot Accuracy of the Ottawa score in risk stratification of recurrent venous thromboembolism in patients with cancer-associated venous thromboembolism: a systematic review and meta-analysis By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 In patients with cancer-associated venous thromboembolism, knowledge of the estimated rate of recurrent events is important for clinical decision-making regarding anticoagulant therapy. The Ottawa score is a clinical prediction rule designed for this purpose, stratifying patients according to their risk of recurrent venous thromboembolism during the first six months of anticoagulation. We conducted a systematic review and meta-analysis of studies validating either the Ottawa score in its original or modified versions. Two investigators independently reviewed the relevant articles published from 1st June 2012 to 15th December 2018 and indexed in MEDLINE and EMBASE. Nine eligible studies were identified; these included a total of 14,963 patients. The original score classified 49.3% of the patients as high-risk, with a sensitivity of 0.7 [95% confidence interval (CI): 0.6-0.8], a 6-month pooled rate of recurrent venous thromboembolism of 18.6% (95%CI: 13.9-23.9). In the low-risk group, the recurrence rate was 7.4% (95%CI: 3.4-12.5). The modified score classified 19.8% of the patients as low-risk, with a sensitivity of 0.9 (95%CI: 0.4-1.0) and a 6-month pooled rate of recurrent venous thromboembolism of 2.2% (95%CI: 1.6-2.9). In the high-risk group, recurrence rate was 10.2% (95%CI: 6.4-14.6). Limitations of our analysis included type and dosing of anticoagulant therapy. We conclude that new therapeutic strategies are needed in patients at high risk for recurrent cancer-associated venous thromboembolism. Low-risk patients, as per the modified score, could be good candidates for oral anticoagulation. (This systematic review was registered with the International Prospective Registry of Systematic Reviews as: PROSPERO CRD42018099506). Full Article
ot The contact system proteases play disparate roles in streptococcal sepsis By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 Sepsis causes an activation of the human contact system, an inflammatory response mechanism against foreign surfaces, proteins and pathogens. The serine proteases of the contact system, factor XII and plasma kallikrein, are decreased in plasma of septic patients, which was previously associated with an unfavorable outcome. However, the precise mechanisms and roles of contact system factors in bacterial sepsis are poorly understood. We, therefore, studied the physiological relevance of factor XII and plasma kallikrein in a mouse model of experimental sepsis. We show that decreased plasma kallikrein concentration in septic mice is a result of reduced mRNA expression plasma prekallikrein gene, indicating that plasma kallikrein belong to negative acute phase proteins. Investigations regarding the pathophysiological function of contact system proteases during sepsis revealed different roles for factor XII and plasma kallikrein. In vitro, factor XII decelerated bacteria induced fibrinolysis, whereas plasma kallikrein supported it. Remarkably, depletion of plasma kallikrein (but not factor XII) by treatment with antisense-oligonucleotides, dampens bacterial dissemination and growth in multiple organs in the mouse sepsis model. These findings identify plasma kallikrein as a novel host pathogenicity factor in Streptococcus pyogenes sepsis. Full Article
ot IL6R-STAT3-ADAR1 (P150) interplay promotes oncogenicity in multiple myeloma with 1q21 amplification By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 1q21 amplification is an important prognostic marker in multiple myeloma. In this study we identified that IL6R (the interleukin-6 membrane receptor) and ADAR1 (an RNA editing enzyme) are critical genes located within the minimally amplified 1q21 region. Loss of individual genes caused suppression to the oncogenic phenotypes, the magnitude of which was enhanced when both genes were concomitantly lost. Mechanistically, IL6R and ADAR1 collaborated to induce a hyper-activation of the oncogenic STAT3 pathway. High IL6R confers hypersensitivity to interleukin-6 binding, whereas, ADAR1 forms a constitutive feed-forward loop with STAT3 in a P150-isoform-predominant manner. In this respect, ADAR1-P150 acts as a direct transcriptional target for STAT3 and this STAT3-induced-P150 in turn directly interacts with and stabilizes the former protein, leading to a larger pool of proteins acting as oncogenic transcription factors for pro-survival genes. The importance of both IL6R and ADAR1-P150 in STAT3 signaling was further validated when concomitant knockdown of both genes impeded IL6-induced-STAT3 pathway activation. Clinical evaluation of various datasets of myeloma patients showed that low expression of either one or both genes was closely associated with a compromised STAT3 signature, confirming the involvement of IL6R and ADAR1 in the STAT3 pathway and underscoring their essential role in disease pathogenesis. In summary, our findings highlight the complexity of the STAT3 pathway in myeloma, in association with 1q21 amplification. This study therefore reveals a novel perspective on 1q21 abnormalities in myeloma and a potential therapeutic target for this cohort of high-risk patients. Full Article
ot Genomic alterations in high-risk chronic lymphocytic leukemia frequently affect cell cycle key regulators and NOTCH1-regulated transcription By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 To identify genomic alterations contributing to the pathogenesis of high-risk chronic lymphocytic leukemia (CLL) beyond the well-established role of TP53 aberrations, we comprehensively analyzed 75 relapsed/refractory and 71 treatment-naïve high-risk cases from prospective clinical trials by single nucleotide polymorphism arrays and targeted next-generation sequencing. Increased genomic complexity was a hallmark of relapsed/refractory and treatment-naïve high-risk CLL. In relapsed/refractory cases previously exposed to the selective pressure of chemo(immuno)therapy, gain(8)(q24.21) and del(9)(p21.3) were particularly enriched. Both alterations affect key regulators of cell-cycle progression, namely MYC and CDKN2A/B. While homozygous CDKN2A/B loss has been directly associated with Richter transformation, we did not find this association for heterozygous loss of CDKN2A/B. Gains in 8q24.21 were either focal gains in a MYC enhancer region or large gains affecting the MYC locus, but only the latter type was highly enriched in relapsed/refractory CLL (17%). In addition to a high frequency of NOTCH1 mutations (23%), we found recurrent genetic alterations in SPEN (4% mutated), RBPJ (8% deleted) and SNW1 (8% deleted), all affecting a protein complex that represses transcription of NOTCH1 target genes. We investigated the functional impact of these alterations on HES1, DTX1 and MYC gene transcription and found derepression of these NOTCH1 target genes particularly with SPEN mutations. In summary, we provide new insights into the genomic architecture of high-risk CLL, define novel recurrent DNA copy number alterations and refine knowledge on del(9p), gain(8q) and alterations affecting NOTCH1 signaling. This study was registered at ClinicalTrials.gov with number NCT01392079. Full Article
ot CXCR4 upregulation is an indicator of sensitivity to B-cell receptor/PI3K blockade and a potential resistance mechanism in B-cell receptor-dependent diffuse large B-cell lymphomas By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 B-cell receptor (BCR) signaling pathway components represent promising treatment targets in multiple B-cell malignancies including diffuse large B-cell lymphoma (DLBCL). In in vitro and in vivo model systems, a subset of DLBCLs depend upon BCR survival signals and respond to proximal BCR/phosphoinositide 3 kinase (PI3K) blockade. However, single-agent BCR pathway inhibitors have had more limited activity in patients with DLBCL, underscoring the need for indicators of sensitivity to BCR blockade and insights into potential resistance mechanisms. Here, we report highly significant transcriptional upregulation of C-X-C chemokine receptor 4 (CXCR4) in BCR-dependent DLBCL cell lines and primary tumors following chemical spleen tyrosine kinase (SYK) inhibition, molecular SYK depletion or chemical PI3K blockade. SYK or PI3K inhibition also selectively upregulated cell surface CXCR4 protein expression in BCR-dependent DLBCLs. CXCR4 expression was directly modulated by fork-head box O1 via the PI3K/protein kinase B/forkhead box O1 signaling axis. Following chemical SYK inhibition, all BCR-dependent DLBCLs exhibited significantly increased stromal cell-derived factor-1α (SDF-1α) induced chemotaxis, consistent with the role of CXCR4 signaling in B-cell migration. Select PI3K isoform inhibitors also augmented SDF-1α induced chemotaxis. These data define CXCR4 upregulation as an indicator of sensitivity to BCR/PI3K blockade and identify CXCR4 signaling as a potential resistance mechanism in BCR-dependent DLBCLs. Full Article
ot Dissecting molecular mechanisms of resistance to NOTCH1-targeted therapy in T-cell acute lymphoblastic leukemia xenografts By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 Despite substantial progress in treatment of T-cell acute lymphoblastic leukemia (T-ALL), mortality remains relatively high, mainly due to primary or acquired resistance to chemotherapy. Further improvements in survival demand better understanding of T-ALL biology and development of new therapeutic strategies. The Notch pathway has been involved in the pathogenesis of this disease and various therapeutic strategies are currently under development, including selective targeting of NOTCH receptors by inhibitory antibodies. We previously demonstrated that the NOTCH1-specific neutralizing antibody OMP52M51 prolongs survival in TALL patient-derived xenografts bearing NOTCH1/FBW7 mutations. However, acquired resistance to OMP52M51 eventually developed and we used patient-derived xenografts models to investigate this phenomenon. Multi-level molecular characterization of T-ALL cells resistant to NOTCH1 blockade and serial transplantation experiments uncovered heterogeneous types of resistance, not previously reported with other Notch inhibitors. In one model, resistance appeared after 156 days of treatment, it was stable and associated with loss of Notch inhibition, reduced mutational load and acquired NOTCH1 mutations potentially affecting the stability of the heterodimerization domain. Conversely, in another model resistance developed after only 43 days of treatment despite persistent down-regulation of Notch signaling and it was accompanied by modulation of lipid metabolism and reduced surface expression of NOTCH1. Our findings shed light on heterogeneous mechanisms adopted by the tumor to evade NOTCH1 blockade and support clinical implementation of antibody-based target therapy for Notch-addicted tumors. Full Article
ot TARP is an immunotherapeutic target in acute myeloid leukemia expressed in the leukemic stem cell compartment By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 Immunotherapeutic strategies targeting the rare leukemic stem cell compartment might provide salvage to the high relapse rates currently observed in acute myeloid leukemia (AML). We applied gene expression profiling for comparison of leukemic blasts and leukemic stem cells with their normal counterparts. Here, we show that the T-cell receptor chain alternate reading frame protein (TARP) is over-expressed in de novo pediatric (n=13) and adult (n=17) AML sorted leukemic stem cells and blasts compared to hematopoietic stem cells and normal myeloblasts (15 healthy controls). Moreover, TARP expression was significantly associated with a fms-like tyrosine kinase receptor-3 internal tandem duplication in pediatric AML. TARP overexpression was confirmed in AML cell lines (n=9), and was found to be absent in B-cell acute lymphocytic leukemia (n=5) and chronic myeloid leukemia (n=1). Sequencing revealed that both a classical TARP transcript, as described in breast and prostate adenocarcinoma, and an AML-specific alternative TARP transcript, were present. Protein expression levels mostly matched transcript levels. TARP was shown to reside in the cytoplasmic compartment and showed sporadic endoplasmic reticulum co-localization. TARP-T-cell receptor engineered cytotoxic T-cells in vitro killed AML cell lines and patient leukemic cells co-expressing TARP and HLA-A*0201. In conclusion, TARP qualifies as a relevant target for immunotherapeutic T-cell therapy in AML. Full Article
ot Oncogenic fusion protein BCR-FGFR1 requires the breakpoint cluster region-mediated oligomerization and chaperonin Hsp90 for activation By www.haematologica.org Published On :: 2020-05-01T00:05:41-07:00 Mutation and translocation of fibroblast growth factor receptors often lead to aberrant signaling and cancer. This work focuses on the t(8;22)(p11;q11) chromosomal translocation which creates the breakpoint cluster region (BCR) fibroblast growth factor receptor1 (FGFR1) (BCR-FGFR1) fusion protein. This fusion occurs in stem cell leukemia/lymphoma, which can progress to atypical chronic myeloid leukemia, acute myeloid leukemia, or B-cell lymphoma. This work focuses on the biochemical characterization of BCR-FGFR1 and identification of novel therapeutic targets. The tyrosine kinase activity of FGFR1 is required for biological activity as shown using transformation assays, interleukin-3 independent cell proliferation, and liquid chromatography/mass spectroscopy analyses. Furthermore, BCR contributes a coiled-coil oligomerization domain, also essential for oncogenic transformation by BCR-FGFR1. The importance of salt bridge formation within the coiled-coil domain is demonstrated, as disruption of three salt bridges abrogates cellular transforming ability. Lastly, BCR-FGFR1 acts as a client of the chaperonin heat shock protein 90 (Hsp90), suggesting that BCR-FGFR1 relies on Hsp90 complex to evade proteasomal degradation. Transformed cells expressing BCR-FGFR1 are sensitive to the Hsp90 inhibitor Ganetespib, and also respond to combined treatment with Ganetespib plus the FGFR inhibitor BGJ398. Collectively, these data suggest novel therapeutic approaches for future stem cell leukemia/lymphoma treatment: inhibition of BCR oligomerization by disruption of required salt bridges; and inhibition of the chaperonin Hsp90 complex. Full Article
ot Prion protein deficiency impairs hematopoietic stem cell determination and sensitizes myeloid progenitors to irradiation By www.haematologica.org Published On :: 2020-05-01T00:05:41-07:00 Highly conserved among species and expressed in various types of cells, numerous roles have been attributed to the cellular prion protein (PrPC). In hematopoiesis, PrPC regulates hematopoietic stem cell self-renewal but the mechanisms involved in this regulation are unknown. Here we show that PrPC regulates hematopoietic stem cell number during aging and their determination towards myeloid progenitors. Furthermore, PrPC protects myeloid progenitors against the cytotoxic effects of total body irradiation. This radioprotective effect was associated with increased cellular prion mRNA level and with stimulation of the DNA repair activity of the Apurinic/pyrimidinic endonuclease 1, a key enzyme of the base excision repair pathway. Altogether, these results show a previously unappreciated role of PrPC in adult hematopoiesis, and indicate that PrPC-mediated stimulation of BER activity might protect hematopoietic progenitors from the cytotoxic effects of total body irradiation. Full Article
ot Genetics of "high-risk" chronic lymphocytic leukemia in the times of chemoimmunotherapy By www.haematologica.org Published On :: 2020-05-01T00:05:41-07:00 Full Article
ot Role of Meningioma 1 for maintaining the transformed state in MLL-rearranged acute myeloid leukemia: potential for therapeutic intervention? By www.haematologica.org Published On :: 2020-05-01T00:05:41-07:00 Full Article
ot Characterization of response and corneal events with extended follow-up after belantamab mafodotin (GSK2857916) monotherapy for patients with relapsed multiple myeloma: a case series from the first-time-in-human clinical trial By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 Full Article
ot Disease progression in myeloproliferative neoplasms: comparing patients in accelerated phase with those in chronic phase with increased blasts (<10%) or with other types of disease progression By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 Full Article
ot Suppressive effects of anagrelide on cell cycle progression and the maturation of megakaryocyte progenitor cell lines in human induced pluripotent stem cells By www.haematologica.org Published On :: 2020-05-01T00:05:42-07:00 Full Article
ot MG53 Does Not Manifest the Development of Diabetes in db/db Mice By diabetes.diabetesjournals.org Published On :: 2020-04-20T12:00:34-07:00 MG53 is a member of the TRIM protein family that is predominantly expressed in striated muscles and participates in cell membrane repair. Controversy exists regarding MG53’s role in insulin signaling and manifestation of diabetes. We generated db/db mice with either whole-body ablation or sustained elevation of MG53 in the bloodstream in order to evaluate the physiological function of MG53 in diabetes. To quantify the amount of MG53 protein in circulation, we developed a monoclonal antibody against MG53 with high specificity. Western blot using this antibody revealed lower or no change of serum MG53 levels in db/db mice or patients with diabetes compared with control subjects. Neither whole-body ablation of MG53 nor sustained elevation of MG53 in circulation altered insulin signaling and glucose handling in db/db mice. Instead, mice with ablation of MG53 were more susceptible to streptozotocin-induced dysfunctional handling of glucose compared with the wild-type littermates. Alkaline-induced corneal injury demonstrated delayed healing in db/db mice, which was restored by topical administration of recombinant human (rh)MG53. Daily intravenous administration of rhMG53 in rats at concentrations up to 10 mg/kg did not produce adverse effects on glucose handling. These findings challenge the hypothetical function of MG53 as a causative factor for the development of diabetes. Our data suggest that rhMG53 is a potentially safe and effective biologic to treat diabetic oculopathy in rodents. Full Article
ot A Phenotypic Screen Identifies Calcium Overload as a Key Mechanism of {beta}-Cell Glucolipotoxicity By diabetes.diabetesjournals.org Published On :: 2020-04-20T12:00:34-07:00 Type 2 diabetes (T2D) is caused by loss of pancreatic β-cell mass and failure of the remaining β-cells to deliver sufficient insulin to meet demand. β-Cell glucolipotoxicity (GLT), which refers to combined, deleterious effects of elevated glucose and fatty acid levels on β-cell function and survival, contributes to T2D-associated β-cell failure. Drugs and mechanisms that protect β-cells from GLT stress could potentially improve metabolic control in patients with T2D. In a phenotypic screen seeking low-molecular-weight compounds that protected β-cells from GLT, we identified compound A that selectively blocked GLT-induced apoptosis in rat insulinoma cells. Compound A and its optimized analogs also improved viability and function in primary rat and human islets under GLT. We discovered that compound A analogs decreased GLT-induced cytosolic calcium influx in islet cells, and all measured β-cell–protective effects correlated with this activity. Further studies revealed that the active compound from this series largely reversed GLT-induced global transcriptional changes. Our results suggest that taming cytosolic calcium overload in pancreatic islets can improve β-cell survival and function under GLT stress and thus could be an effective strategy for T2D treatment. Full Article
ot DLL1- and DLL4-Mediated Notch Signaling Is Essential for Adult Pancreatic Islet Homeostasis By diabetes.diabetesjournals.org Published On :: 2020-04-20T12:00:34-07:00 Genes of the Notch signaling pathway are expressed in different cell types and organs at different time points during embryonic development and adulthood. The Notch ligand Delta-like 1 (DLL1) controls the decision between endocrine and exocrine fates of multipotent progenitors in the developing pancreas, and loss of Dll1 leads to premature endocrine differentiation. However, the role of Delta-Notch signaling in adult tissue homeostasis is not well understood. Here, we describe the spatial expression pattern of Notch pathway components in adult murine pancreatic islets and show that DLL1 and DLL4 are specifically expressed in β-cells, whereas JAGGED1 is expressed in α-cells. We show that mice lacking both DLL1 and DLL4 in adult β-cells display improved glucose tolerance, increased glucose-stimulated insulin secretion, and hyperglucagonemia. In contrast, overexpression of the intracellular domain of DLL1 in adult murine pancreatic β-cells results in impaired glucose tolerance and reduced insulin secretion, both in vitro and in vivo. These results suggest that Notch ligands play specific roles in the adult pancreas and highlight a novel function of the Delta/Notch pathway in β-cell insulin secretion. Full Article
ot Inorganic Nitrate Promotes Glucose Uptake and Oxidative Catabolism in White Adipose Tissue Through the XOR-Catalyzed Nitric Oxide Pathway By diabetes.diabetesjournals.org Published On :: 2020-04-20T12:00:34-07:00 An aging global population combined with sedentary lifestyles and unhealthy diets has contributed to an increasing incidence of obesity and type 2 diabetes. These metabolic disorders are associated with perturbations to nitric oxide (NO) signaling and impaired glucose metabolism. Dietary inorganic nitrate, found in high concentration in green leafy vegetables, can be converted to NO in vivo and demonstrates antidiabetic and antiobesity properties in rodents. Alongside tissues including skeletal muscle and liver, white adipose tissue is also an important physiological site of glucose disposal. However, the distinct molecular mechanisms governing the effect of nitrate on adipose tissue glucose metabolism and the contribution of this tissue to the glucose-tolerant phenotype remain to be determined. Using a metabolomic and stable-isotope labeling approach, combined with transcriptional analysis, we found that nitrate increases glucose uptake and oxidative catabolism in primary adipocytes and white adipose tissue of nitrate-treated rats. Mechanistically, we determined that nitrate induces these phenotypic changes in primary adipocytes through the xanthine oxidoreductase–catalyzed reduction of nitrate to NO and independently of peroxisome proliferator–activated receptor-α. The nitrate-mediated enhancement of glucose uptake and catabolism in white adipose tissue may be a key contributor to the antidiabetic effects of this anion. Full Article
ot Protection Against Insulin Resistance by Apolipoprotein M/Sphingosine-1-Phosphate By diabetes.diabetesjournals.org Published On :: 2020-04-20T12:00:34-07:00 Subjects with low serum HDL cholesterol levels are reported to be susceptible to diabetes, with insulin resistance believed to be the underlying pathological mechanism. Apolipoprotein M (apoM) is a carrier of sphingosine-1-phosphate (S1P), a multifunctional lipid mediator, on HDL, and the pleiotropic effects of HDL are believed to be mediated by S1P. In the current study, we attempted to investigate the potential association between apoM/S1P and insulin resistance. We observed that the serum levels of apoM were lower in patients with type 2 diabetes and that they were negatively correlated with BMI and the insulin resistance index. While deletion of apoM in mice was associated with worsening of insulin resistance, overexpression of apoM was associated with improvement of insulin resistance. Presumably, apoM/S1P exerts its protective effect against insulin resistance by activating insulin signaling pathways, such as the AKT and AMPK pathways, and also by improving the mitochondrial functions through upregulation of SIRT1 protein levels. These actions of apoM/S1P appear to be mediated via activation of S1P1 and/or S1P3. These results suggest that apoM/S1P exerts protective roles against the development of insulin resistance. Full Article
ot Apolipoprotein M and Sphingosine-1-Phosphate: A Potentially Antidiabetic Tandem Carried by HDL By diabetes.diabetesjournals.org Published On :: 2020-04-20T12:00:34-07:00 Full Article
ot "Take Me To Your Leader": An Electrophysiological Appraisal of the Role of Hub Cells in Pancreatic Islets By diabetes.diabetesjournals.org Published On :: 2020-04-20T12:00:34-07:00 The coordinated electrical activity of β-cells within the pancreatic islet drives oscillatory insulin secretion. A recent hypothesis postulates that specially equipped "hub" or "leader" cells within the β-cell network drive islet oscillations and that electrically silencing or optically ablating these cells suppresses coordinated electrical activity (and thus insulin secretion) in the rest of the islet. In this Perspective, we discuss this hypothesis in relation to established principles of electrophysiological theory. We conclude that whereas electrical coupling between β-cells is sufficient for the propagation of excitation across the islet, there is no obvious electrophysiological mechanism that explains how hyperpolarizing a hub cell results in widespread inhibition of islet electrical activity and disruption of their coordination. Thus, intraislet diffusible factors should perhaps be considered as an alternate mechanism. Full Article
ot Pervasive Small RNAs in Cardiometabolic Research: Great Potential Accompanied by Biological and Technical Barriers By diabetes.diabetesjournals.org Published On :: 2020-04-20T12:00:34-07:00 Advances in small RNA sequencing have revealed the enormous diversity of small noncoding RNA (sRNA) classes in mammalian cells. At this point, most investigators in diabetes are aware of the success of microRNA (miRNA) research and appreciate the importance of posttranscriptional gene regulation in glycemic control. Nevertheless, miRNAs are just one of multiple classes of sRNAs and likely represent only a minor fraction of sRNA sequences in a given cell. Despite the widespread appreciation of sRNAs, very little research into non-miRNA sRNA function has been completed, likely due to some major barriers that present unique challenges for study. To emphasize the importance of sRNA research in cardiometabolic diseases, we highlight the success of miRNAs and competitive endogenous RNAs in cholesterol and glucose metabolism. Moreover, we argue that sequencing studies have demonstrated that miRNAs are just the tip of the iceberg for sRNAs. We are likely standing at the precipice of immense discovery for novel sRNA-mediated gene regulation in cardiometabolic diseases. To realize this potential, we must first address critical barriers with an open mind and refrain from viewing non-miRNA sRNA function through the lens of miRNAs, as they likely have their own set of distinct regulatory factors and functional mechanisms. Full Article
ot Abnormal expression of GABAA receptor subunits and hypomotility upon loss of gabra1 in zebrafish [RESEARCH ARTICLE] By bio.biologists.org Published On :: 2020-04-13T03:41:34-07:00 Nayeli G. Reyes-Nava, Hung-Chun Yu, Curtis R. Coughlin II, Tamim H. Shaikh, and Anita M. Quintana We used whole-exome sequencing (WES) to determine the genetic etiology of a patient with a multi-system disorder characterized by a seizure phenotype. WES identified a heterozygous de novo missense mutation in the GABRA1 gene (c.875C>T). GABRA1 encodes the alpha subunit of the gamma-aminobutyric acid receptor A (GABAAR). The GABAAR is a ligand gated ion channel that mediates the fast inhibitory signals of the nervous system, and mutations in the subunits that compose the GABAAR have been previously associated with human disease. To understand the mechanisms by which GABRA1 regulates brain development, we developed a zebrafish model of gabra1 deficiency. gabra1 expression is restricted to the nervous system and behavioral analysis of morpholino injected larvae suggests that the knockdown of gabra1 results in hypoactivity and defects in the expression of other subunits of the GABAAR. Expression of the human GABRA1 protein in morphants partially restored the hypomotility phenotype. In contrast, the expression of the c.875C>T variant did not restore these behavioral deficits. Collectively, these results represent a functional approach to understand the mechanisms by which loss-of-function alleles cause disease. Full Article
ot Methylated Vnn1 at promoter regions induces asthma occurrence via the PI3K/Akt/NF{kappa}B-mediated inflammation in IUGR mice [RESEARCH ARTICLE] By bio.biologists.org Published On :: 2020-04-28T06:57:17-07:00 Yan Xing, Hongling Wei, Xiumei Xiao, Zekun Chen, Hui Liu, Xiaomei Tong, and Wei Zhou Infants with intrauterine growth retardation (IUGR) have a high risk of developing bronchial asthma in childhood, but the underlying mechanisms remain unclear. This study aimed to disclose the role of vascular non-inflammatory molecule 1 (vannin-1, encoded by the Vnn1 gene) and its downstream signaling in IUGR asthmatic mice induced by ovalbumin. Significant histological alterations and an increase of vannin-1 expression were revealed in IUGR asthmatic mice, accompanied by elevated methylation of Vnn1 promoter regions. In IUGR asthmatic mice, we also found (i) a direct binding of HNF4α and PGC1α to Vnn1 promoter by ChIP assay; (ii) a direct interaction of HNF4α with PGC1α; (iii) upregulation of phospho-PI3K p85/p55 and phospho-AktSer473 and downregulation of phospho-PTENTyr366, and (iv) an increase in nuclear NFB p65 and a decrease in cytosolic IB-α. In primary cultured bronchial epithelial cells derived from the IUGR asthmatic mice, knockdown of Vnn1 prevented upregulation of phospho-AktSer473 and an increase of reactive oxygen species (ROS) and TGF-β production. Taken together, we demonstrate that elevated vannin-1 activates the PI3K/Akt/NFB signaling pathway, leading to ROS and inflammation reactions responsible for asthma occurrence in IUGR individuals. We also disclose that interaction of PGC1α and HNF4α promotes methylation of Vnn1 promoter regions and then upregulates vannin-1 expression. Full Article
ot Mothers in medicine: in praise of the home doctor By bjgp.org Published On :: 2020-04-30T16:04:41-07:00 Full Article
ot Digital medical photography recording: a personal view By bjgp.org Published On :: 2020-04-30T16:04:41-07:00 Full Article
ot A broken heart is a door open for others By bjgp.org Published On :: 2020-04-30T16:04:41-07:00 Full Article