Power for refugees: Electricity Audio bhorton.drupal 16 May 2022

A new podcast special explores an often-overlooked aspect of humanitarian assistance: access to energy.

From Afghanistan to Ukraine to Sudan - the world is grappling with the consequences that emerge when people are forced to flee from their homes. One factor that does not usually make the headlines is that many people displaced by conflict or natural disasters lack access to the energy services that are necessary for forging dignified lives and livelihoods. 

This first episode of a two-part Undercurrents special examines efforts to electrify refugee settlements in Ethiopia, Kenya and Rwanda, shedding light on what has worked and what has not. Approximately 94% of forcibly displaced people living in these settlements do not have access to electricity to heat or cool hospitals, schools and dwellings, or to light streets.

Since 2015, Chatham House has been researching this issue and convening dialogues to spur action by humanitarians, energy companies and others. Our seminal Heat, Light and Power report provided the first ever comprehensive assessment of access to energy in refugee camps and urban areas with high numbers of refugees.

This two-part podcast is part of the Renewable Energy for Refugees project. Led by Practical Action, the project provides access to affordable and sustainable sources of renewable energy, and improves the health, wellbeing and security of refugees and neighbouring communities.

Climate migration: Ways ahead from the next generation The World Today rsoppelsa.drupal 25 May 2022

Ella Dennis and Mike Higgins talk to young activists seeking solutions as global warming wreaks havoc in sub-Saharan Africa

Africa has the lowest carbon emissions per capita yet the highest rate of temperature increase in the world. Rising levels of desertification, drought and flooding are already forcing millions of Africans to relocate to find more stable livelihoods. 

The continent’s youth will bear the brunt of this climate migration problem. It is estimated that by 2050, Africa will be home to 86 million internal climate migrants.

How is climate migration already affecting sub-Saharan Africa and what frameworks could tackle it? To begin to answer those questions, five young activists from across the region, who are members of Chatham House’s Common Futures Conversations, took part in a panel discussion at the world’s first youth-led Conference on Climate Migration, convened in April by the Alliance for Citizen Engagement, a nonpartisan think tank based in the US. 

The conversation and follow-up discussions focused on a common problem – climate migration brings people into conflict and puts pressure on infrastructure. 

In Kenya, droughts have left 3.5 million people hungry and the chronic flooding of several lakes in the Rift Valley has displaced hundreds of thousands, said Gerald Muchiri, 29, a social scientist from Kenya. One result has been outbreaks of violence between pastoralists such as the Orma people and the farmers of the Pokomo community, said Laura Mukhwana, 33, a PhD student in Kenya. She believes this violence is likely to worsen. ‘Inter-group conflicts will pose even larger security concerns for surrounding communities as climate migration intensifies,’ she said.

Suleman Nuhu, 24, a farmer and veterinary student from Nigeria, said farmer-herder conflicts were his country’s most significant climate-migration issue. The movement of nomadic tribes from the north had affected him personally: ‘Nomads have trespassed on [my family’s] farms many times while moving with their livestock, destroying our crops.’ 

Changes in climate also force people to move from rural to urban areas. Nigeria, for instance, struggles with the so-called ‘Lagos problem’, said Temiloluwa Lawal, 25, a lawyer and researcher from Nigeria. An estimated 22 million people, a number that is rising fast, are crammed into a city smaller than Greater London. While not on the same scale, Zimbabwe experiences comparable challenges, said Tinotenda Dube, 29, a Zimbabwean finance director. Thanks to drought, unemployed rural migrants arriving in cities ‘put excessive pressure on service delivery against a low tax base,’ he said. ‘People, including close family members of mine, are crowded in dilapidated homes because they cannot afford to pay rent for decent housing.’ 

But there is hope, say the activists. Dube believes that affordable housing is an ‘integral component of [tackling] the climate migration crisis’. 

In Zimbabwe, he has developed a low-cost home finance model that, he said, has helped more than 250 low-income households find good-quality accommodation. Alongside this initiative, Dube has co-founded a property and construction company, Solinfra Zimbabwe Private Ltd, to provide low-cost housing. 

Muchiri is taking action in Kenya, founding an NGO called Social Assistance Welfare to tackle public health issues, he said: ‘As climate migration becomes more intense, I expect preventable health issues to increase throughout the region, and thus see Social Assistance Welfare as an important mitigation.’

In Nigeria, Nuhu noted that to help reduce conflict between farmers and herders social-media campaigns are encouraging pastoralists to move from nomadic livestock farming to more efficient intensive systems, using ranching and grazing reserves. ‘As for food security problems, the best mitigation is to reduce reliance on rain-fed agriculture through irrigation schemes,’ he said. 

All five agreed that, in their experience, the youth of sub-Saharan Africa could be better informed about climate migration. But they took encouragement from the fact the young are passionate about tackling issues arising from the broader climate crisis. 

In Kenya, Mukhwana pointed to successful youth projects around agro-forestry and tree-planting. She added that there is ‘a growing movement of urban youth who are advocating for climate justice, such as the Kenyan Youth Environmental Network and Fridays for the Future Kenya’. It was pleasing too, she said, that when the Kenyan government revised its contributions to the Paris Climate Accords it staged a week-long youth conference to include their opinions.

‘Overall, I am quite hopeful about how the youth are mobilizing themselves in Kenya,’ she added.

Find out more about Chatham House’s Common Futures Conversations
 

What challenges does the new president of Somalia face? Explainer Video aboudiaf.drupal 28 June 2022

Ahmed Soliman examines the challenges the new president Hassan Sheikh Mohamud faces in his first 100 days as president.

Key issues for the new administration are a deteriorating situation with regards to drought as close to half the population are facing food insecurity due to a fourth failed rainy season.

Combined with an inflation rate above ten per cent, many Somalis are at risk of famine and starvation. Many areas of the country are affected from the pastoralist regions to those which house IDP camps around the capital city and other towns, all being exacerbated by the war in Ukraine as Somalia was importing much of its wheat imports from Ukraine and Russia.

Why Ethiopia must close its political gender gap The World Today mhiggins.drupal 29 July 2022

Women urgently need to gain access to high office if the country hopes to survive, say Hilina Berhanu Degefa and Emebet Getachew.

At the end of 2021, Prime Minister Abiy Ahmed’s government announced the formation of a three-year national dialogue to address Ethiopia’s political crisis, looking at the ongoing civil war and conflict, inflation, unemployment, drought and other urgent domestic issues. 

But, while efforts have been made to ensure the participation of women in this dialogue, it must be more than symbolic otherwise gaps in meaningful gender inclusion could have significant implications on the very survival of the country.
 
One of the challenges for meaningful inclusion is that Ethiopia is a highly patriarchal society. Patriarchal norms and practices permeate all aspects of the country’s social, economic and political life. Women constitute over half of the Ethiopian population and represent 41 per cent of the national parliament.

Nevertheless, most political parties, including those with liberal credentials, are exclusively governed by men, with women taking almost no part in key decision-making processes. As a result, women are relegated to the margins of political and economic activities. 

Though there has been little systematic study of the structural challenges faced by Ethiopian women in politics, women members of political parties encounter many barriers, including political violence, male-coded norms and sexist discourses across Ethiopian society.
 
The nature and scale of political violence perpetrated against women is particularly disempowering and affects their ability to participate in political spaces.

While attitudes to gender equality, sexual violence and gender discrimination are often trivialized, they remain ever-present threats in women’s lives. As late as 2016, a significant minority of men still believed wife-beating to be justified in certain situations. Even when women overcome social pressure to pursue their political ambitions, patriarchal views and practices within political party structures about the role of women significantly undermine their active participation and engagement. 

The political space is even more inaccessible to women with disabilities and in conflict and climate-related crises such as among internally displaced people and in pastoral communities. Male-coded norms ingrained at both party and community levels remain a significant concern. Specifically, sex in exchange for candidacy, inconsiderate working schedules affecting women with children and denial of access to equal information and financial resources are frequently reported as major internal hurdles among political parties.

Closing the gender gap could offer Ethiopia a new beginning

Many political initiatives designed to tackle these gender imbalances often have been driven by short-term political considerations without proper gender-gap assessment and policy analysis. In most cases, the authorities have viewed gender-targeted reforms as acts of benevolence, dispensed by the government, without adopting the legal and financial measures necessary to ensure sustainability and impact.
 
Take, for example, Abiy’s appointment of a 50:50 gender-balanced cabinet in 2018. At the time, much was made about its transformative potential, with the prime minister attracting widespread global approval. Yet, a cabinet reshuffle in 2021 reduced female representation to 36.3 per cent, with far less scrutiny or accountability.

This indicates that gender equality in Ethiopia is not considered a priority but rather an endeavour for more opportune, ‘stable’ times. Without thorough measures that create the conditions for real change, the aspiration of having a gender-balanced cabinet will always be challenging to translate into lasting equal representation.
 
The proposed national dialogue presents an ideal opportunity for Ethiopian women to begin reshaping attitudes and closing the gender gap through their inclusion and participation in the political process. To do so, three issues must be addressed.
 
First, the varying rights of women need to be consolidated, including on identity, constitutional reform and economic issues .

Second, gender equality considerations must be absorbed into mainstream political discourse at all levels.

Third, the experiences of women in the recent war, other ongoing conflicts and past and lingering legacies of political violence targeting women from specific communities, must be acknowledged and remedied. 

If Ethiopia is indeed serious about addressing its asymmetric gender power dynamics, this national dialogue provides an excellent opportunity to begin the process. Genuine participation of women as independent actors, with their own agency, could offer Ethiopia a new beginning.

A natural climate change priority for Africa Expert comment LJefferson 28 September 2022

Nature-based solutions can protect African nations’ shared natural endowment and meet the needs of their people.

Africa’s principal climate change negotiators have long understood the important contribution of ‘nature-based solutions’ (NBS) in delivering land (and sea) based options as part of the goals of the Paris Agreement. Limiting temperature rises to only 1.5°C by 2050 will demand finding innovative ways to protect Africa’s vast natural endowment that also meets the equally acute needs of its people. Nature-based solutions may do both.

The urgency for Africa cannot be overstated. At a Chatham House conference in Libreville, the Gabonese minister for the environment highlighted that if global warming surges by 2.5° or 3°C the impact would be at least 6°C for Africa. Decision-makers on the continent and across the world need to understand that ‘business as usual’ cannot be an option given the potential for loss of life, conflict and chaos.

Adaption, mitigation, or both?

Although adaptation to climate change has hitherto tended to be the continent’s main concern, there has also been growing recognition of the ways that Africa’s natural environments, from forests and grasslands, to peatlands and coastal and marine ecosystems, all also mitigate its impacts by sequestering carbon. The Congo Basin alone is said to store upwards of 4 per cent of global emissions annually.

These environments are under increasing pressure. Deforestation is a sad reality, caused mostly by unsustainable and extensive agricultural practices focused on cash crops for export more than food production to feed local populations. And arguing that African states and peoples should slow the development of their economies and infrastructure in response to a crisis born of the already-industrialized world does not find a responsive audience in a continent hungry for jobs and opportunity.

Nature-based solutions offer an answer to this conundrum. There is growing evidence that natural habitats both help avoid losses from climate change-related disasters and can drive economic growth. There is thus potential for NBS to tackle both adaptation and mitigation challenges at relatively low cost.

NBS – the rocky road from commitment to policy

It was logical therefore for Africa and like-minded countries to work to integrate NBS more strongly into the climate change agenda at COP26. The final Glasgow Climate Pact duly emphasized the importance of protecting ecosystems. The Global Forest Finance Pledge signed in the margins was also significant. African focus, with COP 27 in Egypt soon to take place, is now on domestic implementation and delivery of these pledges. The new African Union Climate Change and Resilient Development strategy (2022-2032) sets out many of the challenges and opportunities.

Choosing the right development pathway is tough, requiring political will and inclusive governance. Besides the challenge of securing alternative national revenue if a country moves away from fossil-intensive fuels – particularly acute for Africa’s resource-producing states – there is a dizzying array of policy decisions to be taken. African governments need to choose the most appropriate renewable energy sources, secure alternative livelihoods and continue to meet basic needs of the most vulnerable in the context of radical restructuring.  

Towards African solutions

There can be no one-size-fits-all answer to these questions – it is sadly still necessary to underline the enormous geographic, cultural and political diversity of the continent – but African experts have begun to draw together some emerging common themes from work already underway.  

Maintaining the ‘status quo’ in agricultural practices is no longer an option. Emphasis on sustainable agriculture is urgently needed andthat includes the elaboration of a ‘new deal’ between nature and people.  

Conservation also needs to be reframed as an economic opportunity, particularly in the elaboration and development of ecosystem services that deliver the true value of Africa’s forests, and that involve, value and reward local communities, respecting their rights and livelihoods.

Regional cooperation is likewise key, including on the management of forest, wildlife and water resources – Africa’s ecosystems do not respect arbitrary political boundaries, and accomplishing the dual feat of protecting cross-border systems at the same time as realizing their economic potential will demand effective collaboration, as well as training, education and communication at all levels.

The imperative of finance

A further imperative will be securing sufficient developed country financing – whether that be to secure value for net sequestration and effective forest management or for models of context-appropriate ‘smarter’ sustainable rural conservation and ecosystem resilience.

A new vision for African agency in sustainable development Expert comment LJefferson 18 October 2022

Change is necessary not only in global economic structures and attitudes – but in African governance too.

The conventional notion that Africa is mostly a consumer of norms and practices designed by the Global North has been repeatedly challenged and is increasingly being debunked. Increased African agency in international affairs is today a well-established and documented reality. But Africa’s influence still does not match the scale of the challenges that it faces on its pathway to sustainable development. 

Pushing for African agency in sustainable development also warrants a critical assessment of how ‘sustainable development’ should be defined, and how it can be achieved in terms of actual poverty reduction and real improvement in the lives of local poor Africans. Sustainable development has been a political catchphrase for over 30 years – but a genuine transition towards sustainability has yet to begin.

African agency today

Historically, there have been structural limitations on the agency of African stakeholders to shape development pathways. Chief among them, donor-recipient power dynamics have persistently promoted dependency and sustained institutional corruption. Many African countries are also challenged by economic incentives and infrastructure that have favoured the market demands and supply chains of former colonial powers, which largely remain reliant on natural resource extraction, and are marked by limited investment in value-addition activities and technology development.

Today, however, African agency is being exerted in a more assertive fashion. The African Union (AU), individual African states, civil society, the private sector and eminent and ordinary persons are all displaying Africa’s agency in steering global sustainable development priorities, namely by proposing their own development agenda, The African Union Agenda 2063, adopted in 2013. This was followed by the UN Sustainable Development Goals (Agenda 2030), which in many ways mirror Agenda 2063 – a clear demonstration of the influence of Africa in the global arena. 

Agenda 2063 is a strategic roadmap for Africa ‘to build an integrated, prosperous and peaceful Africa, driven and managed by its own citizens and development goals representing a dynamic force in the international arena’. Prepared following a broad-based participatory consultation, it advocates for inclusion and empowerment and provides an excellent vision for African countries and African people. The SDGs address several of the key shortcomings of their predecessor – the MDGs – and incorporate a broader and more transformative agenda that more adequately reflects the complex challenges of the 21st century and the need for structural reforms in the global economy and governance norms.

In international forums on sustainable development, African countries are increasingly using their collective voice to change the discourse on how development can and should be done. For instance, by championing innovative solutions for carbon markets, African policy leaders are enabling access to climate finance for development while preserving Africa’s natural wealth.

In the post-COVID era, championing investments in and leadership of Africa’s global health architecture demonstrates a desire that in the next pandemic, Africa CDC, AMA and continental manufacturers will play leading roles in determining Africa’s public health strategy and implementation.

In trade, building on the groundwork led by the regional economic commissions, the AfCFTA will catalyse and scale regional integration, trade and cooperation, leading to promising new modes of supply chain and self-sufficiency.

Encouraging signs, but persistent shortcomings

Encouraging signs that African agency is gaining momentum cannot disguise the fact that Africa has yet to move from rhetoric to implementation in the realm of sustainable development. Continental visions often fail to go beyond declarations of intent, and have only limited influence on governance systems or national structural transformation, and African states remain vulnerable to economic shocks emanating from the global system.

Change will require governance systems that are coordinated, transparent, efficient, and inclusive, as well as tools, processes, and means (material, technical, and human) for successful implementation. There is an urgent need for a new governance paradigm in Africa and internationally, dealing with long-term social change.

Notably, African agency should not be only seen as emanating from government, but also as being exerted by independent civil society organizations and committed ordinary individuals. Effective agency needs to be multi-faceted and multi-actor, and depends on the inclusiveness of African governments and their willingness to work with civil society in their strategic engagements with external partners.

Both Agenda 2063 and the SDGs hold the potential for transformation, but implementation will depend on continued advocacy to hold authorities to account and change the dominant discourse, logic and rules of engagement at global, regional, national, and local levels. There is a need for a dynamic new model of African ‘development’.

Time for a new vision

Africa’s economic landscape is changing rapidly, with new regional and local value chains, and integrated regional economic corridors to link countries, minimize the burden of high-cost production and logistics, and boost real incomes and international competitiveness. But Africa continues to face structural challenges, including the need for large investment projects – at a time when Africa remains a net exporter of capital.

Donors and development partners must reflect upon their prior modes of engagement and commit to genuine and equitable relationships with African states. Such partnerships must reflect mutual respect of ideas and accountability, and commit to making space in international forums and multi-lateral arrangements for African people and countries to realize their own visions for progress.

But African leaders and actors must also recognize that with the advent of resources and agency comes responsibility for results and outcomes, notably the need to improve governance. Gaps in accountability, widespread corruption, and lack of successful implementation and sustainability of projects must be addressed.

Africa’s maritime agency cannot be overlooked Expert comment LJefferson 3 November 2022

Increasing maritime awareness has already delivered impact, but consistency and continental leadership are needed to realize the sector’s full potential.

Africa’s 48,000 kilometres of coastline, shared among 38 coastal states, are resource rich and hold some of the world’s most strategic sea lanes, including the approaches to the Suez Canal, which carries 12 per cent of worldwide trade, and the Gulf of Guinea, a critical route for global energy. But despite the vast potential this represents, piracy and maritime insecurity have dominated the narrative of Africa’s coasts, and further propagated the image of African states as beholden to external intervention.

Yet African agency is established and evolving in the sector, with African littoral states enhancing their capacity to face collective security threats and exercising increasing autonomy in responding to the recent rush of external actors looking for port facilities and military bases. Enhanced continental coordination, consistency and leadership can help Africa’s maritime endowment become a resource that can bring sustainable benefit across the continent.  

Agency beyond piracy: the Gulf of Aden and Western Indian Ocean

Piracy became the dominant frame of reference for the East African maritime space as a result of the crisis off the coast of Somalia, which peaked between 2008 and 2012. In 2008, the UN Security Council (UNSC) took the unprecedented step of authorizing international naval operations in Somali territorial waters, contributing to a gradual reduction in attacks. There have been no successful hijackings reported since 2017.

But progress has not just been down to international assistance. Somalia is prioritizing increased domestic enforcement capacity – as demonstrated in the establishment of  a new specialized maritime unit and the wider region enhanced collaboration and information sharing through the Djibouti Code of Conduct of 2009, amended in 2017.

South Africa’s recent admission as a new signatory demonstrates its continued relevance. In March 2022, the UNSC authorization lapsed, following pressure from the Somali government. Although it is not yet clear whether Somali efforts will be sufficient to repress piracy in the long term, this reverse was a clear statement of Somalia’s agency at a level unthinkable during the outset of the crisis.

As the immediate threat of piracy has quietened, broader geopolitical dynamics have come to the fore, notably in a surge by external actors to establish strategic ports and military bases. Here too, African states have demonstrated enhanced agency, for better or worse. Consider Djibouti’s unilateral seizure of a container terminal from an Emirati firm, Sudan’s review of Russian and Turkish deals for maritime facilities, Tanzania’s rejection of a Chinese-led port investment, or the Seychelles withdrawing agreement for an Indian naval base.

Such examples point to a growing awareness of the value of maritime resources within African states, alongside a willingness and ability to push back against external imposition – and indeed to innovate in finding solutions beyond infrastructure and ‘hard’ security. In 2018, the Seychelles launched the world’s first sovereign blue bond to fund sustainable marine projects. That other countries are seeking to replicate this model points to the potentially global impact of African leadership on maritime issues.

Regional cooperation or competition in the Gulf of Guinea?

The Gulf of Guinea is likewise resource rich and geographically strategic, and has faced diverse maritime security threats including piracy, smuggling, illegal fishing, oil theft and pollution. Gulf of Guinea states put in place several initiatives to promote security, including the Yaoundé Code of Conduct (YCoC), signed by 25 states in 2013, that led to information-sharing and cooperation on interdiction, investigation and prosecution. But crime in the Gulf of Guinea nonetheless reached an all-time high in 2020, suffering 130 of the 135 maritime kidnappings recorded worldwide, due to the non-binding nature of the YCoC and gaps in capacity and finance.

Though external actors have become increasingly engaged, including the EU, US, France, Denmark, and the G7++ Group of Friends of the Gulf of Guinea (FOGG), states within the region, especially those most affected by piracy and armed robbery, have nonetheless demonstrated leadership. Nigeria, Ghana, and Cote D’Ivoire have all developed maritime security strategies; Nigeria launched its Deep Blue Project to secure Nigerian waters; Ghana has strengthened its navy; and Togo has changed its laws and judicial system to allow the arrest and prosecution of ships and persons. Maritime security incidents have consequently reduced in 2022.

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Researchers use dynamic PET imaging with target-selective tracer molecules to probe molecular processes. Kinetic models have been developed to describe these processes. The models are typically fitted to the measured PET data with the assumption that the brain is in a steady-state condition for the duration of the scan. The end results are quantitative parameters that characterize the molecular processes. The most common kinetic modeling endpoints are estimates of volume of distribution or the binding potential of a tracer. If the steady state is violated during the scanning period, the standard kinetic models may not apply. To address this issue, time-variant kinetic models have been developed for the characterization of dynamic PET data acquired while significant changes (e.g., short-lived neurotransmitter changes) are occurring in brain processes. These models are intended to extract a transient signal from data. This work in the PET field dates back at least to the 1990s. As interest has grown in imaging nonsteady events, development and refinement of time-variant models has accelerated. These new models, which we classify as belonging to the first, second, or third generation according to their innovation, have used the latest progress in mathematics, image processing, artificial intelligence, and statistics to improve the sensitivity and performance of the earliest practical time-variant models to detect and describe nonsteady phenomena. This review provides a detailed overview of the history of time-variant models in PET. It puts key advancements in the field into historical and scientific context. The sum total of the methods is an ongoing attempt to better understand the nature and implications of neurotransmitter fluctuations and other brief neurochemical phenomena.

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The Internet is full of cats—and in this case, malware-delivering fake cat websites used for very targeted search engine optimization.

Felicia Grasso
Dec 1, 2020; 19:1986-1996
Research

Kyle Swovick
Dec 28, 2020; 0:RA120.002301v1-mcp.RA120.002301
Research

Alison M. Kurimchak
Dec 1, 2020; 19:2068-2089
Research

Litong Nie
Dec 1, 2020; 19:2015-2029
Research

Nadine Prust
Dec 17, 2020; 0:RA120.002232v1-mcp.RA120.002232
Research

Madison T Wright
Nov 18, 2020; 0:RA120.002168v1-mcp.RA120.002168
Research

Xinting Zhang
Dec 8, 2020; 0:RA120.002306v1-mcp.RA120.002306
Research

Mingkun Yang
Nov 24, 2020; 0:RA120.002144v1-mcp.RA120.002144
Research

Qin Zhang
Nov 17, 2020; 0:RA120.002325v1-mcp.RA120.002325
Research

Juntuo Zhou
Nov 30, 2020; 0:RA120.002384v1-mcp.RA120.002384
Research

Kailun Fang
Nov 30, 2020; 0:RA120.002081v1-mcp.RA120.002081
Research

Colin T. McDowell
Nov 24, 2020; 0:RA120.002256v1-mcp.RA120.002256
Research

Laura F Fielden
Nov 11, 2020; 0:RA120.002370v1-mcp.RA120.002370
Research

Congcong Lu
Nov 17, 2020; 0:R120.002257v1-mcp.R120.002257
Review

Adult progenitor cell populations typically exist in a quiescent state within a controlled niche environment. However, various stresses or forms of damage can disrupt this state, which often leads to dysfunction and aging. We built a glucocorticoid (GC)-induced liver damage model of mice, found that GC stress induced liver damage, leading to consequences for progenitor cells expansion. However, the mechanisms by which niche factors cause progenitor cells proliferation are largely unknown. We demonstrate that, within the liver progenitor cells niche, Galectin-3 (Gal-3) is responsible for driving a subset of progenitor cells to break quiescence. We show that GC stress causes aging of the niche, which induces the up-regulation of Gal-3. The increased Gal-3 population increasingly interacts with the progenitor cell marker CD133, which triggers focal adhesion kinase (FAK)/AMP-activated kinase (AMPK) signaling. This results in the loss of quiescence and leads to the eventual stemness exhaustion of progenitor cells. Conversely, blocking Gal-3 with the inhibitor TD139 prevents the loss of stemness and improves liver function. These experiments identify a stress-dependent change in progenitor cell niche that directly influence liver progenitor cell quiescence and function.

Gle1 is a conserved, essential regulator of DEAD-box RNA helicases, with critical roles defined in mRNA export, translation initiation, translation termination, and stress granule formation. Mechanisms that specify which, where, and when DDXs are targeted by Gle1 are critical to understand. In addition to roles for stress-induced phosphorylation and inositol hexakisphosphate binding in specifying Gle1 function, Gle1 oligomerizes via its N-terminal domain in a phosphorylation-dependent manner. However, a thorough analysis of the role for Gle1 self-association is lacking. Here, we find that Gle1 self-association is driven by two distinct regions: a coiled-coil domain and a novel 10-amino acid aggregation-prone region, both of which are necessary for proper Gle1 oligomerization. By exogenous expression in HeLa cells, we tested the function of a series of mutations that impact the oligomerization domains of the Gle1A and Gle1B isoforms. Gle1 oligomerization is necessary for many, but not all aspects of Gle1A and Gle1B function, and the requirements for each interaction domain differ. Whereas the coiled-coil domain and aggregation-prone region additively contribute to competent mRNA export and stress granule formation, both self-association domains are independently required for regulation of translation under cellular stress. In contrast, Gle1 self-association is dispensable for phosphorylation and nonstressed translation initiation. Collectively, we reveal self-association functions as an additional mode of Gle1 regulation to ensure proper mRNA export and translation. This work also provides further insight into the mechanisms underlying human gle1 disease mutants found in prenatally lethal forms of arthrogryposis.

We have observed overexpression of PACS-1, a cytosolic sorting protein in primary cervical tumors. Absence of exonic mutations and overexpression at the RNA level suggested a transcriptional and/or posttranscriptional regulation. University of California Santa Cruz genome browser analysis of PACS-1 micro RNAs (miR), revealed two 8-base target sequences at the 3' terminus for hsa-miR-34a and hsa-miR-449a. Quantitative RT-PCR and Northern blotting studies showed reduced or loss of expression of the two microRNAs in cervical cancer cell lines and primary tumors, indicating dysregulation of these two microRNAs in cervical cancer. Loss of PACS-1 with siRNA or exogenous expression of hsa-miR-34a or hsa-miR-449a in HeLa and SiHa cervical cancer cell lines resulted in DNA damage response, S-phase cell cycle arrest, and reduction in cell growth. Furthermore, the siRNA studies showed that loss of PACS-1 expression was accompanied by increased nuclear γH2AX expression, Lys382-p53 acetylation, and genomic instability. PACS-1 re-expression through LNA-hsa-anti-miR-34a or -449a or through PACS-1 cDNA transfection led to the reversal of DNA damage response and restoration of cell growth. Release of cells post 24-h serum starvation showed PACS-1 nuclear localization at G1-S phase of the cell cycle. Our results therefore indicate that the loss of hsa-miR-34a and hsa-miR-449a expression in cervical cancer leads to overexpression of PACS-1 and suppression of DNA damage response, resulting in the development of chemo-resistant tumors.

The heterotrimeric G proteins are known to have a variety of downstream effectors, but Gs was long thought to be specifically coupled to adenylyl cyclases. A new study indicates that activated Gs can also directly interact with a guanine nucleotide exchange factor for Rho family small GTPases, PDZ-RhoGEF. This novel interaction mediates activation of the small G protein Cdc42 by Gs-coupled GPCRs, inducing cytoskeletal rearrangements and formation of filopodia-like structures. Furthermore, overexpression of a minimal PDZ-RhoGEF fragment can down-regulate cAMP signaling, suggesting that this effector competes with canonical signaling. This first demonstration that the Gαs subfamily regulates activity of Rho GTPases extends our understanding of Gαs activity and establishes RhoGEF coupling as a universal Gα function.

Gα proteins promote dynamic adjustments of cell shape directed by actin-cytoskeleton reorganization via their respective RhoGEF effectors. For example, Gα13 binding to the RGS-homology (RH) domains of several RH-RhoGEFs allosterically activates these proteins, causing them to expose their catalytic Dbl-homology (DH)/pleckstrin-homology (PH) regions, which triggers downstream signals. However, whether additional Gα proteins might directly regulate the RH-RhoGEFs was not known. To explore this question, we first examined the morphological effects of expressing shortened RH-RhoGEF DH/PH constructs of p115RhoGEF/ARHGEF1, PDZ-RhoGEF (PRG)/ARHGEF11, and LARG/ARHGEF12. As expected, the three constructs promoted cell contraction and activated RhoA, known to be downstream of Gα13. Intriguingly, PRG DH/PH also induced filopodia-like cell protrusions and activated Cdc42. This pathway was stimulated by constitutively active Gαs (GαsQ227L), which enabled endogenous PRG to gain affinity for Cdc42. A chemogenetic approach revealed that signaling by Gs-coupled receptors, but not by those coupled to Gi or Gq, enabled PRG to bind Cdc42. This receptor-dependent effect, as well as CREB phosphorylation, was blocked by a construct derived from the PRG:Gαs-binding region, PRG-linker. Active Gαs interacted with isolated PRG DH and PH domains and their linker. In addition, this construct interfered with GαsQ227L's ability to guide PRG's interaction with Cdc42. Endogenous Gs-coupled prostaglandin receptors stimulated PRG binding to membrane fractions and activated signaling to PKA, and this canonical endogenous pathway was attenuated by PRG-linker. Altogether, our results demonstrate that active Gαs can recognize PRG as a novel effector directing its DH/PH catalytic module to gain affinity for Cdc42.

Kinases are critical components of intracellular signaling pathways and have been extensively investigated with regard to their roles in cancer. p21-activated kinase-1 (PAK1) is a serine/threonine kinase that has been previously implicated in numerous biological processes, such as cell migration, cell cycle progression, cell motility, invasion, and angiogenesis, in glioma and other cancers. However, the signaling network linked to PAK1 is not fully defined. We previously reported a large-scale yeast genetic interaction screen using toxicity as a readout to identify candidate PAK1 genetic interactions. En masse transformation of the PAK1 gene into 4,653 homozygous diploid Saccharomyces cerevisiae yeast deletion mutants identified ∼400 candidates that suppressed yeast toxicity. Here we selected 19 candidate PAK1 genetic interactions that had human orthologs and were expressed in glioma for further examination in mammalian cells, brain slice cultures, and orthotopic glioma models. RNAi and pharmacological inhibition of potential PAK1 interactors confirmed that DPP4, KIF11, mTOR, PKM2, SGPP1, TTK, and YWHAE regulate PAK1-induced cell migration and revealed the importance of genes related to the mitotic spindle, proteolysis, autophagy, and metabolism in PAK1-mediated glioma cell migration, drug resistance, and proliferation. AKT1 was further identified as a downstream mediator of the PAK1-TTK genetic interaction. Taken together, these data provide a global view of PAK1-mediated signal transduction pathways and point to potential new drug targets for glioma therapy.

Protein quality control is maintained by a number of integrated cellular pathways that monitor the folding and functionality of the cellular proteome. Defects in these pathways lead to the accumulation of misfolded or faulty proteins that may become insoluble and aggregate over time. Protein aggregates significantly contribute to the development of a number of human diseases such as amyotrophic lateral sclerosis, Huntington's disease, and Alzheimer's disease. In vitro, imaging-based, cellular studies have defined key biomolecular components that recognize and clear aggregates; however, no unifying method is available to quantify cellular aggregates, limiting our ability to reproducibly and accurately quantify these structures. Here we describe an ImageJ macro called AggreCount to identify and measure protein aggregates in cells. AggreCount is designed to be intuitive, easy to use, and customizable for different types of aggregates observed in cells. Minimal experience in coding is required to utilize the script. Based on a user-defined image, AggreCount will report a number of metrics: (i) total number of cellular aggregates, (ii) percentage of cells with aggregates, (iii) aggregates per cell, (iv) area of aggregates, and (v) localization of aggregates (cytosol, perinuclear, or nuclear). A data table of aggregate information on a per cell basis, as well as a summary table, is provided for further data analysis. We demonstrate the versatility of AggreCount by analyzing a number of different cellular aggregates including aggresomes, stress granules, and inclusion bodies caused by huntingtin polyglutamine expansion.

AMP-activated protein kinase (AMPK) is a key regulator of energy metabolism that phosphorylates a wide range of proteins to maintain cellular homeostasis. AMPK consists of three subunits: α, β, and γ. AMPKα and β are encoded by two genes, the γ subunit by three genes, all of which are expressed in a tissue-specific manner. It is not fully understood, whether individual isoforms have different functions. Using RNA-Seq technology, we provide evidence that the loss of AMPKβ1 and AMPKβ2 lead to different gene expression profiles in human induced pluripotent stem cells (hiPSCs), indicating isoform-specific function. The knockout of AMPKβ2 was associated with a higher number of differentially regulated genes than the deletion of AMPKβ1, suggesting that AMPKβ2 has a more comprehensive impact on the transcriptome. Bioinformatics analysis identified cell differentiation as one biological function being specifically associated with AMPKβ2. Correspondingly, the two isoforms differentially affected lineage decision toward a cardiac cell fate. Although the lack of PRKAB1 impacted differentiation into cardiomyocytes only at late stages of cardiac maturation, the availability of PRKAB2 was indispensable for mesoderm specification as shown by gene expression analysis and histochemical staining for cardiac lineage markers such as cTnT, GATA4, and NKX2.5. Ultimately, the lack of AMPKβ1 impairs, whereas deficiency of AMPKβ2 abrogates differentiation into cardiomyocytes. Finally, we demonstrate that AMPK affects cellular physiology by engaging in the regulation of hiPSC transcription in an isoform-specific manner, providing the basis for further investigations elucidating the role of dedicated AMPK subunits in the modulation of gene expression.

Postoperative recurrence from microscopic residual disease must be prevented to cure intractable cancers, including pancreatic cancer. Key to this goal is the elimination of cancer stem cells (CSCs) endowed with tumor-initiating capacity and drug resistance. However, current therapeutic strategies capable of accomplishing this are insufficient. Using in vitro models of CSCs and in vivo models of tumor initiation in which CSCs give rise to xenograft tumors, we show that dexamethasone induces expression of MKP-1, a MAPK phosphatase, via glucocorticoid receptor activation, thereby inactivating JNK, which is required for self-renewal and tumor initiation by pancreatic CSCs as well as for their expression of survivin, an anti-apoptotic protein implicated in multidrug resistance. We also demonstrate that systemic administration of clinically relevant doses of dexamethasone together with gemcitabine prevents tumor formation by CSCs in a pancreatic cancer xenograft model. Our study thus provides preclinical evidence for the efficacy of dexamethasone as an adjuvant therapy to prevent postoperative recurrence in patients with pancreatic cancer.

Akt3 regulates mitochondrial content in endothelial cells through the inhibition of PGC-1α nuclear localization and is also required for angiogenesis. However, whether there is a direct link between mitochondrial function and angiogenesis is unknown. Here we show that Akt3 depletion in primary endothelial cells results in decreased uncoupled oxygen consumption, increased fission, decreased membrane potential, and increased expression of the mitochondria-specific protein chaperones, HSP60 and HSP10, suggesting that Akt3 is required for mitochondrial homeostasis. Direct inhibition of mitochondrial homeostasis by the model oxidant paraquat results in decreased angiogenesis, showing a direct link between angiogenesis and mitochondrial function. Next, in exploring functional links to PGC-1α, the master regulator of mitochondrial biogenesis, we searched for compounds that induce this process. We found that, sildenafil, a phosphodiesterase 5 inhibitor, induced mitochondrial biogenesis as measured by increased uncoupled oxygen consumption, mitochondrial DNA content, and voltage-dependent anion channel protein expression. Sildenafil rescued the effects on mitochondria by Akt3 depletion or pharmacological inhibition and promoted angiogenesis, further supporting that mitochondrial homeostasis is required for angiogenesis. Sildenafil also induces the expression of PGC-1 family member PRC and can compensate for PGC-1α activity during mitochondrial stress by an Akt3-independent mechanism. The induction of PRC by sildenafil depends upon cAMP and the transcription factor CREB. Thus, PRC can functionally substitute during Akt3 depletion for absent PGC-1α activity to restore mitochondrial homeostasis and promote angiogenesis. These findings show that mitochondrial homeostasis as controlled by the PGC family of transcriptional activators is required for angiogenic responses.

The tenovins are a frequently studied class of compounds capable of inhibiting sirtuin activity, which is thought to result in increased acetylation and protection of the tumor suppressor p53 from degradation. However, as we and other laboratories have shown previously, certain tenovins are also capable of inhibiting autophagic flux, demonstrating the ability of these compounds to engage with more than one target. In this study, we present two additional mechanisms by which tenovins are able to activate p53 and kill tumor cells in culture. These mechanisms are the inhibition of a key enzyme of the de novo pyrimidine synthesis pathway, dihydroorotate dehydrogenase (DHODH), and the blockage of uridine transport into cells. These findings hold a 3-fold significance: first, we demonstrate that tenovins, and perhaps other compounds that activate p53, may activate p53 by more than one mechanism; second, that work previously conducted with certain tenovins as SirT1 inhibitors should additionally be viewed through the lens of DHODH inhibition as this is a major contributor to the mechanism of action of the most widely used tenovins; and finally, that small changes in the structure of a small molecule can lead to a dramatic change in the target profile of the molecule even when the phenotypic readout remains static.

Priyanka Tripathi
Dec 30, 2020; 0:jlr.RA120001190v1-jlr.RA120001190
Research Articles

Stephanie E. Hood
Dec 1, 2020; 61:1720-1732
Research Articles