Issue published June 2, 2025 Previous issue

On the cover: New insights into pain

In this issue, review articles by Zeng et al. and Smith et al. explore current thoughts on nonopioid targets for treating acute pain and sex differences in the transition from acute to chronic pain. These reviews highlight recent and ongoing research efforts to develop a better understanding of pain, factors involved in the transition to chronic pain, and innovative approaches to pain management. Image credit: Kathleen Sluka (kathleenslukaart.com).

Review Series Viewpoint
Review Series
Abstract

The gut microbiome has been linked to everything from human behavior to athletic performance to disease pathogenesis. And yet, few universal truths have emerged regarding how the microbiome exerts its effects or responds to the host environment except for one: gut microbiota are exquisitely sensitive to human diets. What we eat from birth onward shapes our gut microbiome composition and function, and this is likely an evolutionarily conserved interaction that benefits the microbe and often the host. However, modern diets and lifestyles have created discordance between our slowly evolving human genome and rapidly adaptable microbiome, and have been implicated in the rise of chronic diseases over the past 75 years. Diet and microbiome interactions have been reviewed extensively, so here we focus on areas of microbiome research that have most illuminated natural and disruptive dietary forces over time in humans, and where we may have opportunities to restore the natural balance of host with microbes in our modern world.

Authors

Carolina Koletic, Amanda Mrad, Anthony Martin, Suzanne Devkota

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Abstract

Bacterial vaginosis (BV) is a polymicrobial condition of the vaginal microbiota associated with a variety of sexually transmitted infections, infections of maternal and fetal tissues during pregnancy, and even some infections outside of the reproductive tract, including the urinary tract and mouth. BV has also been associated with conditions in which the body generates prominent inflammatory reactions to microbes, including infections of the cervix and other upper genital tract tissues. For reasons still not understood, BV is a highly recurrent and often difficult-to-treat condition, complicating attempts to prevent these associated infections. An additional layer of complexity arises from the increasing awareness that the presence of BV-associated bacteria in the vagina is not always symptomatic or associated with adverse outcomes. In this concise Review, we summarize and synthesize three groups of factors grounded in the literature that may be fueling the associations between BV and infection: (a) aspects of society and culture; (b) pathogens, virulence factors, and processes of microbial antagonism and synergy; and (c) host factors, such as genetics and immunity. Our goal is to understand what contexts and combinations of microbial, host, and social factors conspire to make BV virulent in some individuals but not others. Disrupting these patterns more systematically may achieve healthier outcomes.

Authors

Nicole M. Gilbert, Luis A. Ramirez Hernandez, Daniela Berman, Sydney Morrill, Pascal Gagneux, Amanda L. Lewis

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Abstract

A large body of evidence suggests that single- and multiple-strain probiotics and synbiotics could have roles in the management of specific gastrointestinal disorders. However, ongoing concerns regarding the quality and heterogeneity of the clinical data, safety in vulnerable populations, and the lack of regulation of products containing live microbes are barriers to widespread clinical use. Safety and regulatory issues must be addressed and new technologies considered. One alternative future strategy is the use of synthetic bacterial communities, defined as manually assembled consortia of two or more bacteria originally derived from the human gastrointestinal tract. Synthetic bacterial communities can model functional, ecological, and structural aspects of native communities within the gastrointestinal tract, occupying varying nutritional niches and providing the host with a stable, robust, and diverse gut microbiota that can prevent pathobiont colonization by way of colonization resistance. Alternatively, phage therapy is the use of lytic phage to treat bacterial infections. The rise of antimicrobial resistance has led to renewed interest in phage therapy, and the high specificity of phages for their hosts has spurred interest in using phage-based approaches to precisely modulate the microbiome. In this Review, we consider the present and future of microbiome-targeting therapies, with a special focus on early-life applications, such as prevention of necrotizing enterocolitis.

Authors

Lauren E. Lynch, Rachel Lahowetz, Christian Maresso, Austen Terwilliger, Jason Pizzini, Valeria Melendez Hebib, Robert A. Britton, Anthony W. Maresso, Geoffrey A. Preidis

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Reviews
Abstract

Acute pain management has historically been dominated by opioids, whose efficacy is overshadowed by the risks of addiction, tolerance, and dependence, culminating in the global opioid crisis. To transcend this issue, we must innovate beyond opioid-based μ receptor treatments, identifying nonopioid analgesics with high efficacy and minimal adverse effects. This Review navigates the multifaceted landscape of inflammatory, neuropathic, and nociplastic pain, emphasizing mechanism-based analgesic targets tailored to specific pain conditions. We delve into the challenges and breakthroughs in clinical trials targeting ion channels, GPCRs, and other molecular targets. We also highlight the intricate crosstalk between different physiological systems and the need for multimodal interventions with distinct pharmacodynamics to manage acute and chronic pain, respectively. Furthermore, we explore emerging strategies, including gene therapy, stem cell therapy, cell type–specific neuromodulation, and AI-driven techniques for objective, unbiased pain assessment and research. These innovative approaches are poised to revolutionize pain management, paving the way for the discovery of safer and more effective analgesics.

Authors

Xiangsunze Zeng, Rasheen Powell, Clifford J. Woolf

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Abstract

Chronic pain affects more than 50 million Americans, with women disproportionately affected by severe pain, pain interference, and overall disability. The development of chronic pain is multifactorial and often begins with an incident of acute pain associated with an injury or a surgical procedure that transitions to persistent pain lasting for months or years. Despite this, there are limited clinical studies investigating sex differences in predictors and biomarkers for the transition to chronic pain. Several preclinical animal models have been developed to gain a better understanding of the mechanisms for the transition to chronic pain, and several sex-specific mechanisms have been identified across multiple systems. These preclinical models generally involve a multiple-insult approach, in which a priming insult enhances sensitivity to a subsequent induction stimulus. There is emerging evidence from preclinical research for several male-specific and female-specific mechanisms, as well as several studies showing shared mechanisms. Here, we review the clinical and preclinical literature covering sex differences in the periphery and immune system, the central nervous system, and the endocrine system related to the transition to chronic pain. We further highlight gaps in the literature and provide recommendations for future research to understand sex-specific differences in the transition to chronic pain.

Authors

Angela F. Smith, Ashley N. Plumb, Giovanni Berardi, Kathleen A. Sluka

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Commentaries
Abstract

B cell depletion is a highly effective therapy in multiple sclerosis (MS), reducing inflammation and restoring immune balance. In this issue of the JCI, Wei et al. used single-cell RNA-Seq and flow cytometry, identifying the comprehensive effects of B cell depletion on the immune response, including an increase in antiinflammatory cerebrospinal fluid macrophages and elevated TNF-α expression by peripheral CD16+ monocytes. The authors also detected shifts in T cell populations that resulted in reduced myelin-reactive CD4+ T cells and the expansion of TIGIT+ Tregs. The findings uncover immunoregulatory mechanisms and suggest therapeutic strategies for MS and other autoimmune disorders.

Authors

Carolina M. Polonio, Francisco J. Quintana

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Abstract

Accumulating evidence from rodent and human studies indicates that the activity of thermogenic adipocytes positively correlates with optimal metabolic function. In this issue of the JCI, Yesian et al. uncover a paracrine signaling pathway from type 2 innate lymphoid cells to preadipocytes via IL-13 that increases beige adipogenesis through a PPARγ-dependent pathway. Mice with deletion of Il13ra1 demonstrated glucose dysregulation, and variants near the human IL13RA1 locus were associated with body weight and diabetic status. It is tempting to speculate that targeting IL-13 holds therapeutic potential for improving metabolic fitness in humans.

Authors

Margo P. Emont, Jun Wu

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Abstract

Fanconi anemia (FA) is the most common inherited bone marrow failure disorder, caused by pathogenic variants in genes involved in the FA DNA repair pathway. In this issue of the JCI, two studies report three germline homozygous loss-of-function variants in FAAP100, a key component of the FA core complex, identified in three unrelated families. These variants result in severe developmental phenotypes that are among the most extreme reported in FA to date. Harrison et al. described individuals from two families with recurrent pregnancy loss and neonatal death due to homozygous FAAP100 frameshift and truncating variants, respectively. Kuehl et al. identified a homozygous missense variant in a fetus with congenital malformations consistent with FA. Collectively, both studies provide robust functional evidence from ex vivo and in vitro assays with animal models supporting the pathogenicity of these variants and establish FAAP100 as a causative FA gene.

Authors

Claire C. Homan, Hamish S. Scott, Parvathy Venugopal

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Abstract

Cell plasticity is a hallmark of cancer, enabling tumor cells to acquire multiple phenotypes responsible for tumor progression, metastasis, and therapy resistance. In this issue of the JCI, Kawai and colleagues leveraged genetically engineered mouse models (GEMM) of pancreatic ductal adenocarcinoma (PDAC) to demonstrate that loss of Pbrm1, a member of the SWI/SNF complex, drives dedifferentiation and aggressive tumor features. Pbrm1 loss activated a program of epithelial-to-mesenchymal transition (EMT) and allowed the emergence of poorly differentiated histologies that are commonly associated with high recurrence rate and dismal prognosis. These findings reveal the role of the SWI/SNF complex during PDAC evolution in maintaining cell identity and restraining the progression of this lethal disease.

Authors

Luigi Perelli, Giannicola Genovese

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Abstract

Hypertension is a leading cause of morbidity and mortality, with pathologic consequences on multiple end-organ systems. Smooth muscle plasticity and its epigenetic regulation promote disease pathogenesis, but the genetic levers that control such activity are incompletely defined. In this issue of the JCI, Mangum et al. utilized high-density genomic data to define the causal and pathogenic role of a variant at the JMJD3 locus — one that is associated with systolic blood pressure and governs an allele-specific molecular mechanism controlling smooth muscle behavior in hypertension. These findings have clinical implications relevant to patient risk stratification and personalized therapeutics.

Authors

Lloyd D. Harvey, Stephen Y. Chan

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Research Letter
Abstract

Authors

Anna S. Pollack, Christian A. Kunder, Chandler C. Ho, Josephine Chou, Andrew J. Pollack, Rachel L.P. Geisick, Bing M. Zhang, Robert B. West, James D. Brooks, Jonathan R. Pollack

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Research Articles
Abstract

Type 2 innate lymphoid cells (ILC2s) regulate the proliferation of preadipocytes that give rise to beige adipocytes. Whether and how ILC2 downstream Th2 cytokines control beige adipogenesis remain unclear. We used cell systems and genetic models to examine the mechanism through which IL-13, an ILC2-derived Th2 cytokine, controls beige adipocyte differentiation. IL-13 priming in preadipocytes drove beige adipogenesis by upregulating beige-promoting metabolic programs, including mitochondrial oxidative metabolism and PPARγ-related pathways. The latter was mediated by increased expression and activity of PPARγ through the IL-13 receptor 1 (IL-13R1) downstream effectors STAT6 and p38 MAPK, respectively. Il13-KO or preadipocyte Il13ra1-KO mice were refractory to cold- or β3-adrenergic agonist–induced beiging in inguinal white adipose tissue, whereas Il4-KO mice showed no defects in beige adipogenesis. Il13-KO and Il13ra1-KO mouse models exhibited increased body weight and fat mass and dysregulated glucose metabolism but had a mild cold-intolerant phenotype, likely due to their intact brown adipocyte recruitment. We also found that genetic variants of human IL13RA1 were associated with BMI and type 2 diabetes. These results suggest that IL-13 signaling–regulated beige adipocyte function may play a predominant role in modulating metabolic homeostasis rather than in thermoregulation.

Authors

Alexandra R. Yesian, Mayer M. Chalom, Nelson H. Knudsen, Alec L. Hyde, Jean Personnaz, Hyunjii Cho, Yae-Huei Liou, Kyle A. Starost, Chia-Wei Lee, Dong-Yan Tsai, Hsing-Wei Ho, Jr-Shiuan Lin, Jun Li, Frank B. Hu, Alexander S. Banks, Chih-Hao Lee

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Abstract

Acute myeloid leukemia (AML) is an aggressive and often deadly malignancy associated with proliferative immature myeloid blasts. Here, we identified CD84 as a critical survival regulator in AML. High levels of CD84 expression provided a survival advantage to leukemia cells, whereas CD84 downregulation disrupted their proliferation, clonogenicity, and engraftment capabilities in both human cell lines and patient-derived xenograft cells. Critically, loss of CD84 also markedly blocked leukemia engraftment and clonogenicity in MLL-AF9 and inv(16) AML mouse models, highlighting its pivotal role as a survival factor across species. Mechanistically, CD84 regulated leukemia cells’ energy metabolism and mitochondrial dynamics. Depletion of CD84 altered mitochondrial ultrastructure and function of leukemia cells, and it caused downmodulation of both oxidative phosphorylation and fatty acid oxidation pathways. CD84 knockdown induced a block of Akt phosphorylation and downmodulation of nuclear factor erythroid 2-related factor 2 (NRF2), impairing AML antioxidant defense. Conversely, CD84 overexpression stabilized NRF2 and promoted its transcriptional activation, thereby supporting redox homeostasis and mitochondrial function in AML. Collectively, our findings indicate that AML cells depend on CD84 to support antioxidant prosurvival pathways, highlighting a therapeutic vulnerability of leukemia cells.

Authors

Yinghui Zhu, Mariam Murtadha, Miaomiao Liu, Enrico Caserta, Ottavio Napolitano, Le Xuan Truong Nguyen, Huafeng Wang, Milad Moloudizargari, Lokesh Nigam, Theophilus Tandoh, Xuemei Wang, Alex Pozhitkov, Rui Su, Xiangjie Lin, Marc Denisse Estepa, Raju Pillai, Joo Song, James F. Sanchez, Yu-Hsuan Fu, Lianjun Zhang, Man Li, Bin Zhang, Ling Li, Ya-Huei Kuo, Steven Rosen, Guido Marcucci, John C. Williams, Flavia Pichiorri

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Abstract

Mutations in Polybromo 1 (PBRM1), a subunit of the switch/sucrose nonfermentable (SWI/SNF) chromatin remodeling complex, are frequently observed in several cancers, including pancreatic ductal adenocarcinoma (PDAC). In this study, we demonstrated that pancreas-specific loss of Pbrm1 in mice harboring Kras mutations and Trp53 deletions accelerated the development of poorly differentiated PDAC, epithelial-mesenchymal transition (EMT), and metastasis, resulting in worsened prognosis. Pbrm1 loss in preexisting PDAC shifted the tumor grade from a well- to a poorly differentiated state and elevated vimentin expression. Pbrm1-null PDAC exhibited downregulation of apical junction genes and upregulation of EMT pathway genes, including the vimentin and squamous molecular subtype signature genes. Mechanistically, PBRM1 bound to the vimentin gene promoter and directly downregulated its expression. Furthermore, suppression of vimentin in Pbrm1-null PDAC cells reversed the dedifferentiation phenotype and reduced EMT and metastasis. Consistently, reduced PBRM1 expression correlated with high vimentin expression, poorly differentiated histology, a high recurrence rate, and reduced overall survival in human PDACs. Additionally, PDAC with PBRM1 deletion was associated with the aggressive squamous molecular subtype. Our data established PBRM1 as a tumor suppressor that controls tumor grade and metastasis of PDAC by regulating vimentin expression.

Authors

Munenori Kawai, Akihisa Fukuda, Munehiro Ikeda, Kei Iimori, Kenta Mizukoshi, Kosuke Iwane, Go Yamakawa, Mayuki Omatsu, Mio Namikawa, Makoto Sono, Tomonori Masuda, Yuichi Fukunaga, Munemasa Nagao, Osamu Araki, Takaaki Yoshikawa, Satoshi Ogawa, Yukiko Hiramatsu, Motoyuki Tsuda, Takahisa Maruno, Yuki Nakanishi, Dieter Saur, Tatsuaki Tsuruyama, Toshihiko Masui, Etsuro Hatano, Hiroshi Seno

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Abstract

Maladaptive fear generalization is one of the hallmarks of trauma-related disorders. The endocannabinoid 2-arachidonoylglycerol (2-AG) is crucial for modulating anxiety, fear, and stress adaptation, but its role in balancing fear discrimination versus generalization is not known. To address this, we used a combination of plasma endocannabinoid measurement and neuroimaging in a childhood maltreatment–exposed and –nonexposed mixed population, combined with human and rodent fear-conditioning models. Here we show that 2-AG levels were inversely associated with fear generalization at the behavioral level in both mice and humans. In mice, 2-AG depletion increased the proportion of neurons that respond to, and the similarity of neuronal representations for, both threat-predictive and neutral stimuli within prelimbic prefrontal cortex neuronal ensembles. In humans, increased dorsolateral prefrontal cortical–amygdala resting-state connectivity was inversely correlated with fear generalization. These data provide convergent cross-species evidence that 2-AG is a key regulator of fear generalization and further support the notion that 2-AG deficiency could represent a trauma-related disorder-susceptibility endophenotype.

Authors

Luis E. Rosas-Vidal, Saptarnab Naskar, Leah M. Mayo, Irene Perini, Rameen Masroor, Megan Altemus, Liorimar Ramos-Medina, S. Danyal Zaidi, Hilda Engelbrektsson, Puja Jagasia, Markus Heilig, Sachin Patel

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Abstract

Spinal microglia play a pivotal role in the development of neuropathic pain. Peripheral nerve injury induces changes in the transcriptional profile of microglia, including increased expression of components of the translational machinery. Whether microglial protein synthesis is stimulated following nerve injury and has a functional role in mediating pain hypersensitivity is unknown. Here, we show that nascent protein synthesis is upregulated in spinal microglia following peripheral nerve injury in both male and female mice. Stimulating mRNA translation in microglia by selectively ablating the translational repressor eukaryotic initiation factor 4E–binding protein 1 (4E-BP1) promoted the transition of microglia to a reactive state and induced mechanical hypersensitivity in both sexes, whereas spontaneous pain was increased only in males. Conversely, inhibiting microglial translation by expressing a mutant form of 4E-BP1 in microglia attenuated their activation following peripheral nerve injury and alleviated neuropathic pain in both sexes. Thus, stimulating 4E-BP1–dependent translation promotes microglial reactivity and mechanical hypersensitivity, whereas inhibiting it alleviates neuropathic pain.

Authors

Kevin C. Lister, Calvin Wong, Weihua Cai, Sonali Uttam, Patricia Stecum, Rose Rodrigues, Mehdi Hooshmandi, Nicole Brown, Jonathan Fan, Noe Francois-Saint-Cyr, Shannon Tansley, Volodya Hovhannisyan, Diana Tavares-Ferreira, Nikhil Nageshwar Inturi, Khadijah Mazhar, Alain Pacis, Jieyi Yang, Alfredo Ribeiro-da-Silva, Christos G. Gkogkas, Theodore J. Price, Jeffrey S. Mogil, Arkady Khoutorsky

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Abstract

Hyaluronan (HA) in the extracellular matrix promotes epithelial-mesenchymal transition (EMT) and metastasis; however, the mechanism by which the HA network constructed by cancer cells regulates cancer progression and metastasis in the tumor microenvironment (TME) remains largely unknown. In this study, inter-α-trypsin inhibitor heavy chain 2 (ITIH2), an HA-binding protein, was confirmed to be secreted from mesenchymal-like lung cancer cells when cocultured with cancer-associated fibroblasts. ITIH2 expression is transcriptionally upregulated by the EMT-inducing transcription factor ZEB1, along with HA synthase 2 (HAS2), which positively correlates with ZEB1 expression. Depletion of ITIH2 and HAS2 reduced HA matrix formation and the migration and invasion of lung cancer cells. Furthermore, ZEB1 facilitates alternative splicing and isoform expression of CD44, an HA receptor, and CD44 knockdown suppresses the motility and invasiveness of lung cancer cells. Using a deep learning–based drug-target interaction algorithm, we identified an ITIH2 inhibitor (sincalide) that inhibited HA matrix formation and migration of lung cancer cells, preventing metastatic colonization of lung cancer cells in mouse models. These findings suggest that ZEB1 remodels the HA network in the TME through the regulation of ITIH2, HAS2, and CD44, presenting a strategy for targeting this network to suppress lung cancer progression.

Authors

Sieun Lee, Jihye Park, Seongran Cho, Eun Ju Kim, Seonyeong Oh, Younseo Lee, Sungsoo Park, Keunsoo Kang, Dong Hoon Shin, Song Yi Ko, Jonathan M. Kurie, Young-Ho Ahn

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Abstract

Colorectal cancer (CRC) is characterized by an immune-suppressive microenvironment that contributes to tumor progression and immunotherapy resistance. The gut microbiome produces diverse metabolites that feature unique mechanisms of interaction with host targets, yet the role of many metabolites in CRC remains poorly understood. In this study, the microbial metabolite 4-hydroxybenzeneacetic acid (4-HPA) promoted the infiltration of PMN myeloid-derived suppressor cells (PMN-MDSCs) in the tumor microenvironment, consequently inhibiting the antitumor response of CD8+ T cells and promoting CRC progression in vivo. Mechanistically, 4-HPA activates the JAK2/STAT3 pathway, which upregulates CXCL3 transcription, thereby recruiting PMN-MDSCs to the CRC microenvironment. Selective knockdown of CXCL3 resensitized tumors to anti-PD-1 immunotherapy in vivo. Chlorogenic acid reduces the production of 4-HPA by microbiota, likewise abolishing 4-HPA–mediated immunosuppression. The 4-HPA content in CRC tissues was notably increased in patients with advanced CRC. Overall, the gut microbiome uses 4-HPA as a messenger to control chemokine-dependent accumulation of PMN-MDSC cells and regulate antitumor immunity in CRC. Our findings provide a scientific basis for establishing clinical intervention strategies to reverse the tumor immune microenvironment and improve the efficacy of immunotherapy by reducing the interaction among intestinal microbiota, tumor cells, and tumor immune cells.

Authors

Qing Liao, Ximing Zhou, Ling Wu, Yuyi Yang, Xiaohui Zhu, Hangyu Liao, Yujie Zhang, Weidong Lian, Feifei Zhang, Hui Wang, Yanqing Ding, Liang Zhao

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Abstract

Nuclear clearance and cytoplasmic aggregation of TAR DNA-binding protein 43 (TDP-43) are observed in many neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Although TDP-43 dysregulation of splicing has emerged as a key event in these diseases, TDP-43 can also regulate polyadenylation; yet this has not been adequately studied. Here, we applied the dynamic analysis of polyadenylation from an RNA-Seq (DaPars) tool to ALS/FTD transcriptome datasets and report extensive alternative polyadenylation (APA) upon TDP-43 alteration in ALS/FTD cell models and postmortem ALS/FTD neuronal nuclei. Importantly, many identified APA genes highlight pathways implicated in ALS/FTD pathogenesis. To determine the functional relevance of APA elicited by TDP-43 nuclear depletion, we examined microtubule affinity regulating kinase 3 (MARK3). Nuclear loss of TDP-43 yielded increased expression of MARK3 transcripts with longer 3′ UTRs, corresponding with a change in the subcellular distribution of MARK3 and increased neuronal tau S262 phosphorylation. Our findings define changes in polyadenylation site selection as a previously understudied feature of TDP-43–driven disease pathology in ALS/FTD and highlight a potentially important mechanistic link between TDP-43 dysfunction and tau regulation.

Authors

Frederick J. Arnold, Ya Cui, Sebastian Michels, Michael R. Colwin, Cameron M. Stockford, Wenbin Ye, Vidhya Maheswari Jawahar, Karen Jansen-West, Julien Philippe, Ravinder Gulia, Yunzi Gou, Oliver H. Tam, Sneha Menon, Wendy G. Situ, Saira L. Cazarez, Aryan Zandi, Kean C.K. Ehsani, Sierra Howard, Dennis W. Dickson, Molly Gale Hammell, Mercedes Prudencio, Leonard Petrucelli, Wei Li, Albert R. La Spada

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Abstract

Multiple sclerosis (MS) is a complex, genetically mediated autoimmune disease of the CNS, in which anti-CD20–mediated B cell depletion is remarkably effective in the treatment of early disease. Although previous studies investigated the effect of B cell depletion on select immune cell subsets using flow cytometry–based methods, the therapeutic effect on the patient’s immune landscape is unknown. In this study, we explored how B cell–depleting therapies modulate the immune landscape using single-cell RNA-Seq. We demonstrate that B cell depletion led to cell-type–specific changes in the abundance and function of cerebrospinal fluid (CSF) macrophages and peripheral blood monocytes. Specifically, a CSF-specific macrophage population with an antiinflammatory transcriptomic signature and peripheral CD16+ monocytes increased in frequency after B cell depletion. This was accompanied by increases in TNF-α mRNA and protein levels in monocytes following B cell depletion, consistent with the finding that anti–TNF-α treatment exacerbated autoimmune activity in MS. In parallel, B cell depletion induced changes in peripheral CD4+ T cell populations, including increases in the frequency of TIGIT+ Tregs and marked decreases in the frequency of myelin peptide–loaded, tetramer-binding CD4+ T cells. Collectively, this study provides an exhaustive transcriptomic map of immunological changes, revealing different cell-type–specific reprogramming as a result of B cell depletion treatment of MS.

Authors

Jessica Wei, Jeonghyeon Moon, Yoshiaki Yasumizu, Le Zhang, Khadir Radassi, Nicholas Buitrago-Pocasangre, M. Elizabeth Deerhake, Nicolas Strauli, Chun-Wei Chen, Ann Herman, Rosetta Pedotti, Catarina Raposo, Isaiah Yim, Jenna Pappalardo, Erin E. Longbrake, Tomokazu S. Sumida, Pierre-Paul Axisa, David A. Hafler

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Abstract

Neutrophils are the most abundant immune cells that constantly patrol or marginate inside vascular beds to support immune homeostasis. The extent to which neutrophils undergo reprogramming in response to the changes in vascular architecture and the resultant biological implications of such adaptations remain unclear. Here, we performed intravital imaging and transcriptional profiling to investigate neutrophil behavior across different tissues. Our findings revealed that neutrophils had significant deformability and spontaneous calcium signaling while navigating through the narrow pulmonary vessels. Pulmonary neutrophils exhibited unique transcriptional profiles and were specialized for proangiogenic functions. We found that the mechanosensitive ion channel Piezo-type mechanosensitive ion channel component 1 (PIEZO1) was essential for neutrophil reprogramming. Deletion of Piezo1 in neutrophils ablated the lung-specific proangiogenic transcriptional signature and impaired capillary angiogenesis in both physiological and pathological conditions. Collectively, these data show that mechanical adaptation of neutrophils within the pulmonary vasculature drives their reprogramming in the lungs and promotes pulmonary vascular homeostasis.

Authors

Jin Wang, Wenying Zhao, Wenjuan Bai, Dong Dong, Hui Wang, Xin Qi, Ajitha Thanabalasuriar, Youqiong Ye, Tian-le Xu, Hecheng Li, Paul Kubes, Bin Li, Jing Wang

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Abstract

The antimetastatic activity of NK cells is well established in several cancer types, but the mechanisms underlying NK cell metastasis infiltration and acquisition of antitumor characteristics remain unclear. Herein, we investigated the cellular and molecular factors required to facilitate the generation of an ILC1-like CD49a+ NK cell population within the liver metastasis (LM) environment of colorectal cancer (CRC). We show that CD49a+ NK cells had the highest cytotoxic capacity among metastasis-infiltrating NK cells in the MC38 mouse model. Furthermore, the chemokine receptor CXCR3 promoted CD49a+ NK cell accumulation and persistence in metastasis where NK cells colocalize with macrophages in CXCL9- and CXCL10-rich areas. By mining a published scRNA-seq dataset of a cohort of patients with CRC who were treatment naive, we confirmed the accumulation of CXCR3+NK cells in metastatic samples. Conditional deletion of Cxcr3 in NKp46+ cells and antibody-mediated depletion of metastasis-associated macrophages impaired CD49a+NK cell development, indicating that CXCR3 and macrophages contribute to efficient NK cell localization and polarization in LM. Conversely, CXCR3neg NK cells maintained a CD49a– phenotype in metastasis with reduced parenchymal infiltration and tumor killing capacity. Furthermore, CD49a+ NK cell accumulation was impaired in an independent SL4-induced CRC metastasis model, which fails to accumulate CXCL9+ macrophages. Together, our results highlight a role for CXCR3/ligand axis in promoting macrophage-dependent NK cell accumulation and functional sustenance in CRC LM.

Authors

Eleonora Russo, Chiara D’Aquino, Chiara Di Censo, Mattia Laffranchi, Luana Tomaipitinca, Valerio Licursi, Stefano Garofalo, Johann Promeuschel, Giovanna Peruzzi, Francesca Sozio, Anna Kaffke, Cecilia Garlanda, Ulf Panzer, Cristina Limatola, Christian A.J. Vosshenrich, Silvano Sozzani, Giuseppe Sciumè, Angela Santoni, Giovanni Bernardini

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Abstract

The Wnt/β-catenin pathway regulates expression of the SOX9 gene, which encodes sex-determining region Y–box (SOX) transcription factor 9, a differentiation factor and potential β-catenin regulator. Because APC tumor suppressor defects in approximately 80% of colorectal cancers (CRCs) activate the Wnt/β-catenin pathway, we studied SOX9 inactivation in CRC biology. Compared with effects of Apc inactivation in mouse colon tumors, combined Apc and Sox9 inactivation instigated more invasive tumors with epithelial-mesenchymal transition (EMT) and SOX2 stem cell factor upregulation. In an independent mouse CRC model with combined Apc, Kras, and Trp53 defects, Sox9 inactivation promoted SOX2 induction and distant metastases. About 20% of 171 human CRCs showed loss of SOX9 protein expression, which correlated with higher tumor grade. In an independent group of 376 patients with CRC, low SOX9 gene expression was linked to poor survival, earlier age at diagnosis, and increased lymph node involvement. SOX9 expression reductions in human CRC were linked to promoter methylation. EMT pathway gene expression changes were prominent in human CRCs with low SOX9 expression and in a mouse cancer model with high SOX2 expression. Our results indicate SOX9 has tumor suppressor function in CRC; its loss may promote progression, invasion, and poor prognosis by enhancing EMT and stem cell phenotypes.

Authors

Ying Feng, Ningxin Zhu, Karan Bedi, Jinju Li, Chamila Perera, Maranne Green, Naziheh Assarzadegan, Yali Zhai, Qingzhi Liu, Veerabhadran Baladandayuthapani, Jason R. Spence, Kathleen R. Cho, Eric R. Fearon

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Abstract

Idiopathic pulmonary fibrosis (IPF) is a devastating interstitial lung disease characterized by the excessive accumulation of activated myofibroblasts that deposit extracellular matrix (ECM) protein, leading to progressive scar formation and mechanical stress. However, the cellular origin and fate of myofibroblasts remain controversial, and the mechanisms by which myofibroblasts sense mechanical cues in the lung are unclear. Here, we report that periostin (Postn) is a reliable and distinctive marker for pulmonary myofibroblasts, while ablation of Postn+ myofibroblasts after injury ameliorated lung fibrosis. PIEZO1 was highly expressed in Postn+ myofibroblast and played a vital role in mechanoactivation of Postn+ myofibroblast and development of lung fibrosis. Conditional deletion of Piezo1 in Postn+ myofibroblasts significantly inhibited lung fibrosis by suppressing myofibroblast activation and proliferation. Loss of Piezo1 led to disruption of actin organization and prevention of Yap/Taz nuclear localization, thus shifting the myofibroblasts from a proliferative state into a stressed and apoptotic state. Furthermore, myofibroblast-specific Yap/Taz deletion fully recapitulated the protective phenotypes of myofibroblast-Piezo1–KO mice. These findings show that periostin marks pulmonary myofibroblasts, and that PIEZO1-mediated mechanosensation is essential for myofibroblast activation in the lung. Targeting PIEZO1 in the periostin-expressing cells is a novel therapeutic option to interfere with fibrotic diseases such as IPF .

Authors

Liran Xu, Ting Li, Yapeng Cao, Yu He, Zehua Shao, Siyu Liu, Bianbian Wang, Ailing Su, Huijing Tian, Yongxin Li, Guozheng Liang, Changhe Wang, John Shyy, Ying Xiong, Fangyuan Chen, Jason X.J. Yuan, Junjun Liu, Bin Zhou, Nina Wettschureck, Stefan Offermanns, Yang Yan, Zuyi Yuan, Shengpeng Wang

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Abstract

Fanconi anemia (FA) is a rare genetic disease characterized by loss-of-function variants in any of the 22 previously identified genes (FANCA–FANCW) that encode proteins participating in the repair of DNA interstrand crosslinks (ICLs). Patient phenotypes are variable but may include developmental abnormalities, early-onset pancytopenia, and a predisposition to hematologic and solid tumors. Here, we describe 2 unrelated families with multiple pregnancy losses and offspring presenting with severe developmental and hematologic abnormalities leading to death in utero or in early life. Homozygous loss-of-function variants in FAAP100 were identified in affected children of both families. The FAAP100 protein associates with FANCB and FANCL, the E3 ubiquitin ligase responsible for the monoubiquitination of FANCD2 and FANCI, which is necessary for FA pathway function. Patient-derived cells exhibited phenotypes consistent with FA. Expression of the WT FAAP100 cDNA, but not the patient-derived variants, rescued the observed cellular phenotypes. This establishes FAAP100 deficiency as a cause of FA, with FAAP100 gaining an alias as FANCX. The extensive developmental malformations of individuals with FAAP100 loss-of-function variants are among the most severe across previously described FA phenotypes, indicating that the FA pathway is essential for human development.

Authors

Benjamin A. Harrison, Emma Mizrahi-Powell, John Pappas, Kristen Thomas, Subrahmanya Vasishta, Shripad Hebbar, Anju Shukla, Shalini S. Nayak, Tina K. Truong, Amy Woroch, Yara Kharbutli, Bruce D. Gelb, Cassie S. Mintz, Gilad D. Evrony, Agata Smogorzewska

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Abstract

Long-standing hypertension (HTN) affects multiple organs and leads to pathologic arterial remodeling, which is driven by smooth muscle cell (SMC) plasticity. To identify relevant genes regulating SMC function in HTN, we considered Genome Wide Association Studies (GWAS) of blood pressure, focusing on genes encoding epigenetic enzymes, which control SMC fate in cardiovascular disease. Using statistical fine mapping of the KDM6 Jumonji domain-containing protein D3 (JMJD3) locus, we found that rs62059712 is the most likely casual variant, with each major T allele copy associated with a 0.47 mmHg increase in systolic blood pressure. We show that the T allele decreased JMJD3 transcription in SMCs via decreased SP1 binding to the JMJD3 promoter. Using our unique SMC-specific Jmjd3-deficient murine model (Jmjd3fl/flMyh11CreERT), we show that loss of Jmjd3 in SMCs results in HTN due to decreased endothelin receptor B (EDNRB) expression and increased endothelin receptor A (EDNRA) expression. Importantly, the EDNRA antagonist BQ-123 reversed HTN after Jmjd3 deletion in vivo. Additionally, single-cell RNA-Seq (scRNA-Seq) of human arteries revealed a strong correlation between JMJD3 and EDNRB in SMCs. Further, JMJD3 is required for SMC-specific gene expression, and loss of JMJD3 in SMCs increased HTN-induced arterial remodeling. Our findings link a HTN-associated human DNA variant with regulation of SMC plasticity, revealing targets that may be used in personalized management of HTN.

Authors

Kevin D. Mangum, Qinmengge Li, Katherine Hartmann, Tyler M. Bauer, Sonya J. Wolf, James Shadiow, Jadie Y. Moon, Emily C. Barrett, Amrita D. Joshi, Gabriela Saldana de Jimenez, Zara Ahmed, Rachael Wasikowski, Kylie Boyer, Andrea T. Obi, Frank M. Davis, Lin Chang, Lam C. Tsoi, Johann Gudjonsson, Scott M. Damrauer, Katherine A. Gallagher

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Abstract

Aortic aneurysm is a high-risk cardiovascular disease without an effective cure. Vascular smooth muscle cell (VSMC) phenotypic switching is a key step in the pathogenesis of aortic aneurysm. Here, we revealed the role of histidine triad nucleotide-binding protein 1 (HINT1) in aortic aneurysm. HINT1 was upregulated both in aortic tissue from patients with aortic aneurysm and angiotensin II–induced aortic aneurysm mice. VSMC-specific HINT1 deletion alleviated aortic aneurysm via preventing VSMC phenotypic switching. With the stimulation of pathological factors, the increased nuclear translocation of HINT1 mediated by nucleoporin 98 promoted the interaction between HINT1 and transcription factor AP-2 α (TFAP2A), further triggered the transcription of integrin α6 (ITGA6) mediated by TFAP2A, and consequently activated the downstream focal adhesion kinase (FAK)/STAT3 signal pathway, leading to aggravation of VSMC phenotypic switching and aortic aneurysm. Importantly, defactinib treatment was demonstrated to limit aortic aneurysm development by inhibiting the FAK signal pathway. Thus, the HINT1/ITGA6/FAK axis emerges as a potential therapeutic strategy in aortic aneurysm.

Authors

Yan Zhang, Wencheng Wu, Xuehui Yang, Shanshan Luo, Xiaoqian Wang, Qiang Da, Ke Yan, Lulu Hu, Shixiu Sun, Xiaolong Du, Xiaoqiang Li, Zhijian Han, Feng Chen, Aihua Gu, Liansheng Wang, Zhiren Zhang, Bo Yu, Chenghui Yan, Yaling Han, Yi Han, Liping Xie, Yong Ji

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Abstract

BACKGROUND The neonatal immune system is uniquely poised to generate broadly neutralizing antibodies (bnAbs), and thus infants are ideal for evaluating HIV vaccine candidates. We present the design and safety of a new-in-infants glucopyranosyl lipid A–stable emulsion (GLA-SE) adjuvant admixed with a first-in-infant CH505 transmitter-founder (CH505TF) gp120 immunogen designed to induce precursors for bnAbs against HIV.METHODS HIV Vaccine Trials Network 135 is a phase I randomized, placebo-controlled trial of CH505TF plus GLA-SE or placebo. Healthy infants aged ≤5 days, born to mothers living with HIV but HIV nucleic acid–negative at birth, were randomized to 5 doses of CH505TF plus GLA-SE or placebo at birth and 8, 16, 32, and 54 weeks.RESULTS Thirty-eight infants (median age 4 days; interquartile range 4–4.75 days) were enrolled November 2020 to January 2022. Among 28 infants assigned to receive CH505TF plus GLA-SE and 10 assigned to receive placebo, most completed the 5-dose immunization series (32/38) and follow-up (35/38). Solicited local and systemic reactions were more frequent in vaccine (8, 28.6% local; 16, 57.1% systemic) versus placebo recipients (1, 10% local, P = 0.25; 4, 40.0% systemic, P = 0.38). All events were grade 1 except 2 grade 2 events (pain, lethargy). Serious vaccine-related adverse events were not recorded.CONCLUSION This study illustrates the feasibility of conducting trials of new-in-infants adjuvanted HIV vaccines in HIV-exposed infants receiving standard infant vaccinations. The safety profile of the CH505TF plus GLA-SE vaccine was reassuring.TRIAL REGISTRATION ClinicalTrials.gov NCT04607408.FUNDING National Institute of Allergy and Infectious Diseases of the NIH under grants UM1AI068614, UM1AI068635, and UM1AI068618.

Authors

Avy Violari, Kennedy Otwombe, William Hahn, Shiyu Chen, Deirdre Josipovic, Vuyelwa Baba, Asimenia Angelidou, Kinga K. Smolen, Ofer Levy, Nonhlanhla N. Mkhize, Amanda S. Woodward Davis, Troy M. Martin, Barton F. Haynes, Wilton B. Williams, Zachary K. Sagawa, James G. Kublin, Laura Polakowski, Margaret Brewinski Isaacs, Catherine Yen, Georgia Tomaras, Lawrence Corey, Holly Janes, Glenda E. Gray

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Abstract

The Fanconi anemia/breast cancer (FA/BRCA) DNA repair network promotes the removal of DNA interstrand crosslinks (ICLs) to counteract their devastating consequences, including oncogenesis. Network signaling is initiated by the FA core complex, which consists of 7 authentic FA proteins and an FA-associated protein, FAAP100, with incompletely characterized roles and unknown disease associations. Upon activation, the FA core complex functions as a multiprotein E3 ubiquitin ligase centered on its catalytic module, the FANCB-FANCL-FAAP100 (BLP100) subcomplex, for FANCD2 and FANCI monoubiquitylation. Here, we identified a homozygous variant in FAAP100, c.1642A>C, predicting p.(T542P), in a fetus with malformations suggestive of FA. The mutation caused sensitivity to ICL-inducing agents in cells from the affected individual and genetically engineered, FAAP100-inactivated human, avian, zebrafish, and mouse cells. All FAAP100-deficient cell types were rescued by ectopic expression of WT FAAP100, but not FAAP100T542P. In a confirmatory animal model, customized Faap100–/– mice exhibited embryonic lethality, microsomia, malformations, and gonadal atrophy resembling mice with established FA subtypes. Mechanistically, FAAP100T542P impaired ligase activity by preventing BLP100 subcomplex formation, resulting in defective FAAP100T542P nuclear translocation and chromatin recruitment. FAAP100 dysfunction that disrupted the FA pathway and impaired genomic maintenance, together with FA-consistent human manifestations, recommends FAAP100 as a legitimate FA gene, alias FANCX.

Authors

Julia Kuehl, Yutong Xue, Fenghua Yuan, Ramanagouda Ramanagoudr-Bhojappa, Simone Pickel, Reinhard Kalb, Settara C. Chandrasekharappa, Weidong Wang, Yanbin Zhang, Detlev Schindler

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Abstract

Lineage plasticity is recognized as a critical determinant of lethality and resistance to AR pathway inhibitors in prostate cancer. Lineage plasticity is a continuum, ranging from AR activity-low tumors, AR-null tumors that do not express a neuroendocrine prostate cancer (NEPC) program (i.e., double-negative prostate cancer [DNPC]), and AR-null NEPC tumors. Factors upregulated early in lineage plasticity are not well-characterized. The clarification of such factors is essential to identify tumors undergoing lineage plasticity or at risk of this occurring. Our integrative analysis of metastatic prostate cancer patient tumors, patient-derived xenografts, and cell models determined that PROX1 is upregulated early in the lineage plasticity continuum and progressively increases as tumors lose AR activity. We determined DNA methylation is a key regulator of PROX1 expression. PROX1 suppression in DNPC and NEPC reduces cell survival and impacts apoptosis and differentiation, demonstrating PROX1’s functional importance. PROX1 is not directly targetable with standard drug development approaches. However, affinity immunopurification demonstrated histone deacetylases (HDACs) are among the top PROX1-interacting proteins; HDAC inhibition depletes PROX1 and recapitulates PROX1 suppression in DNPC and NEPC. Altogether, our results suggest PROX1 promotes the emergence of lineage plasticity, and HDAC inhibition is a promising approach to treat tumors across the lineage plasticity continuum.

Authors

Zhi Duan, Mingchen Shi, Anbarasu Kumaraswamy, Dong Lin, Dhruv Khokhani, Yong Wang, Chao Zhang, Diana Flores, Eva Rodansky, Olivia A. Swaim, William K. Storck, Hannah N. Beck, Radhika A. Patel, Erolcan Sayar, Brian P. Hanratty, Hui Xue, Xin Dong, Zoe R. Maylin, Rensheng Wan, David A. Quigley, Martin Sjöström, Ya-Mei Hu, Faming Zhao, Zheng Xia, Siyuan Cheng, Xiuping Yu, Felix Y. Feng, Li Zhang, Rahul Aggarwal, Eric J. Small, Visweswaran Ravikumar, Arvind Rao, Karan Bedi, John K. Lee, Colm Morrissey, Ilsa Coleman, Peter S. Nelson, Eva Corey, Aaron M. Udager, Ryan J. Rebernick, Marcin P. Cieslik, Arul M. Chinnaiyan, Joel A. Yates, Michael C. Haffner, Yuzhuo Wang, Joshi J. Alumkal

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Abstract

Loss-of-function mutations in genome maintenance genes fuel tumorigenesis through increased genomic instability. A subset of these tumor suppressors are challenging to identify due to context dependency, including functional interactions with other genes and pathways. Here, we searched for potential causal genes that impact tumor development and/or progression in breast cancer through functional-genetic screening of candidate genes. MYH4, encoding a class II myosin, emerged as a top hit impacting genomic stability. We show that MYH4 suppresses DNA replication stress by promoting replication licensing and replication fork progression. Moreover, we observed a strong synergistic relationship among class II myosins in suppressing replication-associated DNA damage. Genomic analysis of Pan-Cancer Analysis of Whole Genomes project breast cancer samples revealed frequent concomitant loss of TP53 with MYH4 and class II myosins on chromosome 17p. Notably, Myh4 disruption accelerated mouse mammary tumorigenesis in a Trp53-deficient background. In conclusion, our results suggest an unanticipated function of MYH4 in p53-mediated tumor suppression that can explain their combined loss in breast cancer.

Authors

Jayashree Thatte, Ana Moisés da Silva, Judit Börcsök, Thorkell Gudjónsson, Jan Benada, Xin Li, Muthiah Bose, Hanneke van der Gulden, Ji-Ying Song, Renée Menezes, Elena Martín-Doncel, Luis Toledo, Valdemaras Petrosius, Cord Brakebusch, Jos Jonkers, Finn Cilius Nielsen, Maria Rossing, Claus S. Sørensen

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Abstract

Glycogenolysis and gluconeogenesis ensure sufficient hepatic glucose production during energy shortages. Here, we report that hepatic glycogen levels control the phosphorylation of a transcriptional coactivator to determine the amplitude of gluconeogenesis. Decreased liver glycogen during fasting promotes gluconeogenic gene expression, while feeding-induced glycogen accumulation suppresses it. Liver-specific deletion of the glycogen scaffolding protein, protein targeting to glycogen (PTG), reduces glycogen levels, increases the expression of gluconeogenic genes, and promotes glucose production in primary hepatocytes. In contrast, liver glycogen phosphorylase (PYGL) knockdown or inhibition increases glycogen levels and represses gluconeogenic gene expression. These changes in hepatic glycogen levels are sensed by AMP-activated protein kinase (AMPK). AMPK activity is increased when glycogen levels decline, resulting in the phosphorylation and stabilization of CREB-regulated transcriptional coactivator 2 (CRTC2), which is crucial for the full activation of the cAMP-responsive transcriptional factor CREB. High glycogen allosterically inhibits AMPK, leading to CRTC2 degradation and reduced CREB transcriptional activity. Hepatocytes with low glycogen levels or high AMPK activity show higher CRTC2 protein levels, priming the cell for gluconeogenesis through transcriptional regulation. Thus, glycogen plays a regulatory role in controlling hepatic glucose metabolism through the glycogen/AMPK/CRTC2 signaling axis, safeguarding efficient glucose output during fasting and suppressing it during feeding.

Authors

Bichen Zhang, Morgan M. Johnson, Timothy Yuan, Tammy-Nhu Nguyen, Junichi Okada, Fajun Yang, Alus M. Xiaoli, Liana H. Melikian, Songran Xu, Benyamin Dadpey, Jeffrey E. Pessin, Alan R. Saltiel

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Abstract

Activating the immune costimulatory receptor 4-1BB (CD137) with agonist antibody binding and crosslinking-inducing agents that elicit 4-1BB intracellular signaling potentiates the antitumor responses of CD8+ T cells. However, the underlying in-depth mechanisms remain to be defined. Here, we show that agonistic 4-1BB treatment of activated CD8+ T cells under continuous antigenic stimulation makes them more metabolically vulnerable to redox perturbation by ablation of intracellular glutathione (GSH) and glutathione peroxidase 4 (GPX4) inhibition. Further, genetic deletion of adenosine A2B receptor (A2BR) induces superior survival and expansion advantage of competent CD8+ T cells with agonistic 4-1BB costimulation, leading to more effective antitumor efficacy of adoptive cell therapy (ACT). Mechanistically, A2BR deletion helps sustain the increased energy and biosynthetic requirements through the GSH/GPX4 axis upon 4-1BB costimulation. A2BR deletion in combination with agonistic 4-1BB costimulation displays a greater ability to promote antitumor CD8+ effector T cell survival and expansion while mitigating T cell exhaustion. Thus, the A2BR pathway plays an important role in metabolic reprogramming with potentiation of the GSH/GPX4 cascade upon agonistic 4-1BB costimulation that allows the fine-tuning of the antitumor responses of CD8+ T cells.

Authors

Jihae Ahn, Ping Xie, Siqi Chen, Guilan Shi, Jie Fan, Minghui Zhang, Hui Tang, Amanda R. Zuckerman, Deyu Fang, Yong Wan, Timothy M. Kuzel, Yi Zhang, Bin Zhang

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Corrigendum
Abstract

Authors

Valerie Blanc, Jesse D. Riordan, Saeed Soleymanjahi, Joseph H. Nadeau, ILKe Nalbantoglu, Yan Xie, Elizabeth A. Molitor, Blair B. Madison, Elizabeth M. Brunt, Jason C. Mills, Deborah C. Rubin, Irene O. Ng, Yeonjung Ha, Lewis R. Roberts, Nicholas O. Davidson

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Abstract

Tryptophan hydroxylase (TPH) is a rate-limiting enzyme for serotonin or 5-hydroxytryptamine (5-HT) synthesis. Previously, adipocyte TPH1 has been linked to increased adipose 5-HT, reduced BAT thermogenesis, and obesity. However, the role of TPH2, a neural isoform highly expressed in obese adipose tissue, is unknown. Here, we report that adipose tissue expression of TPH2 is significantly elevated in both diet-induced obese (DIO) and ob/ob mice, as well as in obese humans. In high-fat diet (HFD)-fed mice, adipocyte TPH2 deficiency improves DIO-induced metabolic complications, enhances BAT thermogenesis, and increases intestinal energy harvesting efficiency without affecting adiposity. Conversely, TPH2 overexpression in epididymal adipocytes of chow-fed mice raises adipose and plasma 5-HT levels, suppresses BAT thermogenesis, and exacerbates obesity and metabolic dysfunction. We found that obesity-induced hyperinsulinemia upregulates adipocyte TPH2 expression via activation of mechanistic target of rapamycin complex 1 (mTORC1) and sterol regulatory element binding protein 1 (SREBP1). In humans, TPH2 mRNA levels in subcutaneous adipose tissue, but not TPH1, is positively correlated with fasting plasma insulin concentrations. In summary, our study demonstrates that obesity-associated increases in adipocyte TPH2 can regulate distal tissue physiology and energy metabolism, suggesting that TPH2 could be a potential therapeutic target for obesity and its associated complications.

Authors

Brian I. Park, Andrew R. Reeves, Ying Zhu, Robin A. Wilson, Sophia C. Fernandes, Kimberly K. Buhman, Kelli A. Lytle, Michael D. Jensen, Andrew S. Greenberg

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Abstract

Graft endothelial cells (ECs) express donor alloantigens and encounter cytotoxic T lymphocytes (CTLs) but are generally spared during T cell-mediated rejection (TCMR), which predominantly affects epithelial structures. The mechanisms underlying this vascular immune privilege are unclear. Transcriptomic analyses and endothelial-mesenchymal transition assessments confirmed that the graft endothelium is preserved during TCMR. Co-culture experiments revealed that endothelial and epithelial cells are equally susceptible to CTL-mediated lysis, ruling out cell-intrinsic protection. Intravital microscopy of murine kidney grafts and single-cell RNA sequencing of human renal allografts demonstrated that CTL interactions with ECs are transient compared to epithelial cells. This disparity is mediated by a chemotactic gradient produced by graft stromal cells, guiding CTLs away from ECs toward epithelial targets. In vitro, chemotaxis overrode TCR-induced cytotoxicity, preventing endothelial damage. Finally, analysis of TCMR biopsies revealed that disruption of the chemotactic gradient correlates with endothelialitis lesions, linking its loss to vascular damage. These findings challenge the traditional view of cell-intrinsic immune privilege, proposing a cell-extrinsic mechanism where chemotaxis preserves graft vasculature during TCMR. This mechanism may have implications beyond transplantation, highlighting its role in maintaining vascular integrity across pathological conditions.

Authors

T. Barba, M. Oberbarnscheidt, G. Franck, C. Gao, S. This, M. Rabeyrin, C. Roufosse, L. Moran, A. Koenig, V. Mathias, C. Saison, V. Dubois, N. Pallet, D. Anglicheau, B. Lamarthée, A. Hertig, E. Morelon, A Hot, H. Paidassi, T. Defrance, A. Nicoletti, J.P. Duong-Van-Huyen, Y. Xu-Dubois, F.G. Lakkis, O. Thaunat

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Abstract

Anemia is the primary clinical manifestation of myelodysplastic syndromes (MDS), but the molecular pathogenesis of ineffective erythropoiesis remains incompletely understood. Luspatercept, an activin receptor 2B (ACVRIIB-Fc) ligand trap, has been approved to treat anemia, however its molecular mechanism of action is unclear. We found that the ACVR2B, its ligand GDF11, and effector, SMAD2, are upregulated in MDS patient samples. GDF11 inhibited human erythropoiesis in vitro and caused anemia in zebrafish, effects that were abrogated by luspatercept. Upon GDF11 stimulation of human erythroid progenitors, SMAD2 binding occurred in the erythroid regulatory regions, including at GATA1 intron. Intronic SMAD2 binding led to skipping of exon 2 of GATA1, resulting in a shorter, hypomorphic isoform (GATA1s). CRISPR deletion of the SMAD2 binding intronic region decreased GATA1s production upon GDF11 stimulation. Expression of gata1s in a mouse model led to anemia, rescued by a murine ActRIIB-Fc (RAP-536). Finally, RNA-seq analysis of samples from the Phase 3 MEDALIST trial revealed that responders to Luspatercept had a higher proportion of GATA1s compared to non-responders. Moreover, the increase RBCs post-treatment was linked to a relative decrease in GATA1s isoform. Our study indicates that GDF11-mediated SMAD2 activation results in an increase in functionally impaired GATA1 isoforms, consequently contributing to anemia and influencing responses to Luspatercept in MDS.

Authors

Srinivas Aluri, Te Ling, Ellen Fraint, Samarpana Chakraborty, Kevin Zhang, Aarif Ahsan, Leah Kravets, Gowri Poigaialwar, Rongbao Zhao, Kith Pradhan, Anitria Cotton, Kimo Bachiashvili, Jung-In Yang, Anjali Budhathoki, Beamon Agarwal, Shanisha Gordon-Mitchell, Milagros Carbajal, Srabani Sahu, Jacqueline Boultwood, Andrea Pellagatti, Ulrich Steidl, Amittha Wickrema, Satish Nandakumar, Aditi Shastri, Rajasekhar N.V.S. Suragani, Teresa V. Bowman, John D. Crispino, Sadanand Vodala, Amit Verma

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Abstract

Air pollution is a serious environmental threat to public health; however, the molecular basis underlying its detrimental effects on respiratory fitness remains poorly understood. Here, we show that exposure to particulate matter ≤2.5 µm (PM2.5), a significant fraction of air pollutants, induces the generation of reactive aldehyde species in the airway. We identified aldehyde dehydrogenase 1A1 (ALDH1A1), which is selectively expressed in airway epithelium, as an enzyme responsible for detoxifying these reactive aldehyde species. Loss of ALDH1A1 function results in the accumulation of aldehyde adducts in the airway, which selectively impairs mucociliary clearance (MCC), a critical defense mechanism against respiratory pathogens. Thus, ALDH1A1-deficient mice pre-exposed to PM2.5 exhibited increased susceptibility to pneumonia. Conversely, pharmacological enhancement of ALDH1A1 activity promoted the restoration of MCC function. These findings elucidate the critical role of aldehyde metabolism in protecting against PM2.5 exposure, offering a potential target to mitigate the negative health consequences of air pollution.

Authors

Noriko Shinjyo, Haruna Kimura, Tomomi Yoshihara, Jun Suzuki, Masaya Yamaguchi, Shigetada Kawabata, Yasutaka Okabe

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Abstract

Immune and clinical outcomes to Mycobacterium tuberculosis (Mtb) infection vary greatly between individuals yet the underlying genetic and cellular mechanisms driving this heterogeneity remain poorly understood. We performed a cellular genome-wide association study (GWAS) to identify genetic variants associated with Mtb-induced monocyte transcriptional expression of IL1B, IL6, TNF, and IFNB1 via RNA-seq in a Ugandan cohort. Significantly associated variants were assessed for transferability in an independent Seattle cohort, further validated in vitro, and assessed for clinical phenotype associations. We identified 77 loci suggestively associated with Mtb-induced cytokine expression in monocytes in Uganda. SNPs associated with Mtb-induced TNF were enriched within alpha-linolenic acid metabolism pathway genes which was validated in vitro using PLA2 inhibitors. Four loci maintained significant associations in Seattle. We validated cytokine effect with siRNA knockdown for two of these loci which mapped to the genes SLIT3 and SLC1A1. Furthermore, exogenous treatment of macrophages with SLIT3 enhanced Mtb intracellular replication. Finally, SLC1A1 and SLIT3 variants were associated with susceptibility to tuberculous meningitis (TBM) and subsequent survival in a Vietnamese cohort, respectively. In sum, we identified multiple variants and pathways associated with Mtb-induced cytokine transcriptional responses that validated in vitro and were associated with clinical TB susceptibility.

Authors

Joshua J. Ivie, Kimberly A. Dill-McFarland, Jason D. Simmons, Glenna J. Peterson, Penelope H. Benchek, Harriet Mayanja-Kizza, Lily E. Veith, Moeko Agata, Dang T.M. Ha, Ho D.T. Nghia, W. Henry Boom, Catherine M. Stein, Chiea C. Khor, Guy E. Thwaites, Hoang T. Hai, Nguyen T.T. Thuong, Xuling Chang, Sarah J. Dunstan, Thomas R. Hawn

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Complement Biology and Therapeutics

Series edited by Claudia Kemper

The complement system executes an evolutionarily ancient innate immune response with important roles in many human diseases, including a variety of conditions involving the kidney, autoimmune disorders, age-related macular degeneration, and more. This series of reviews, curated by Dr. Claudia Kemper, highlights the latest discoveries in complement biology and examines ongoing efforts to target complement therapeutically. From the relatively newly uncovered functions of intracellular complement (complosome) to the complexities involved in using animal models of complementopathies, these reviews convey the challenges of studying complement and developing complement-targeted therapeutics as well as call attention to recent findings that supply momentum to the field.

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