Issue published July 1, 2025 Previous issue

On the cover: Targeting of MTAP synergizes with PARP inhibitors in triple-negative breast cancer

Zeng et al. report that deficiency in methylthioadenosine phosphorylase (MTAP), a key enzyme in the methionine salvage pathway, sensitizes triple-negative breast cancer to PARP inhibition by reducing s-adenosylmethionine (SAM) and impairing DNA damage repair. The cover art depicts-triple negative breast cancer cells being targeted by a combination of small molecule inhibitors of PARP (green) and MTAP (blue). Image credit: Xiangyu Zeng.

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Review Series
Abstract

Metabolic dysfunction–associated steatotic liver disease (MASLD) is the most common pediatric liver disease, affecting approximately 10% of children. Its prevalence is rising at an alarming rate, with cases increasingly identified even in early childhood. While MASLD shares key features across the lifespan, its earlier onset reflects developmental vulnerabilities and unique mechanistic drivers. Perinatal influences, including maternal obesity, gestational diabetes, and early-life nutritional exposures, play a central role by disrupting metabolic programming, driving mitochondrial dysfunction, and inducing epigenetic modifications. These early stressors interact with genetic predispositions, such as PNPLA3 and TM6SF2 variants, to amplify susceptibility and shape disease severity. Pediatric MASLD also exhibits distinct histological features, particularly predominant periportal (zone 1) steatosis, inflammation, and fibrosis, which contrast with the centrilobular or pericentral (zone 3) patterns often seen in adults. These findings provide insight into spatial heterogeneity, developmental pathophysiology, and unique disease progression trajectories in children. Addressing MASLD in children requires pediatric-specific approaches to diagnosis, risk stratification, and intervention. By integrating epidemiological trends, mechanistic insights, and translational advances, this Review highlights opportunities for targeted therapies and prevention strategies aimed at mitigating early-life drivers of MASLD, reducing disease burden, and improving long-term outcomes.

Authors

Jeffrey B. Schwimmer, Sudha B. Biddinger, Samar H. Ibrahim

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Abstract

Metabolic dysfunction–associated steatohepatitis (MASH), the progressive inflammatory form of MASLD, is now a leading cause of chronic liver disease worldwide. Driven by obesity and type 2 diabetes, MASH significantly increases the risk of cirrhosis, hepatocellular carcinoma, and liver failure. While public health interventions remain essential, therapeutic strategies targeting metabolic dysfunction, inflammation, and fibrosis are urgently needed. This Review focuses on pharmacological treatments in advanced development, including incretin-based therapies (GLP-1, dual, and triple agonists), metabolic modulators (PPAR, FGF21, and THR-β agonists), and novel agents such as fatty acid synthase inhibitors. Current regulatory approval is based on histological end points, with increasing interest in noninvasive biomarkers and personalized treatment approaches. Recent trials with agents such as semaglutide, tirzepatide, survodutide, lanifibranor, pegozafermin, and resmetirom demonstrate substantial promise in resolving MASH and improving fibrosis, but unresolved issues remain regarding treatment duration, response heterogeneity, and long-term adherence. Genetic variants (e.g., PNPLA3 polymorphisms) and emerging molecular biomarkers may enhance stratification, while artificial intelligence is beginning to shape trial design and drug development. As the field moves toward combination therapies and precision medicine, the definition of therapeutic success will likely evolve to reflect both histological improvement and patient-reported outcomes. This Review provides a timely synthesis of the landscape, challenges, and future directions in MASH therapeutics.

Authors

Philip N. Newsome, Rohit Loomba

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Reviews
Abstract

Endometriosis is an estrogen-dependent chronic inflammatory syndrome characterized by viable endometrial tissue outside the uterine cavity and associated with pain and infertility. Endometriosis, as tissue or a pathological process, is dynamic in that its establishment and progression require repeated episodes of retrograde travel of shed endometrial tissue, which implants in the lower abdominal cavity following ovulatory cycles and survives. Estrogen-rich follicular fluid released onto peritoneal surfaces during ovulation may also support endometriotic implants. DNA evidence indicates that endometriosis originates from eutopic endometrial tissue, which may reach the abdominal cavity in a retrograde manner primarily via the uterine tubes. Unlike uterine bleeding associated with non-ovulatory circumstances, retrograde menstruation following an ovulation maximizes shedding of epithelial cells localized to deep invaginations of the basalis portion of the endometrium, which likely carry somatic cancer-driver mutations such as KRAS. The attached endometrial stromal cells are mostly mutation free but display epigenetic defects including overexpression of aromatase and estrogen receptor-β and downregulation of progesterone receptor, causing estrogen excess and progesterone resistance. These tissue clones may form implants in involuting ovarian corpus luteum cysts and peritoneal surfaces and induce tissue remodeling and fibrosis, manifested as deep-infiltrating endometriosis. The first-line treatment for chronic pelvic pain associated with endometriosis is suppression of ovulation, with the goal of relieving pain. Infertility is often managed using in vitro fertilization, which improves the embryo quality and alters endometrial development.

Authors

Serdar E. Bulun

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Abstract

Cancer care is being transformed by therapies leveraging T lymphocytes to attack tumor cells. In parallel, recent basic discoveries have converged into a framework of lymphocyte-dependent immunity as a regenerative process that is sometimes outstripped by high-level engagement. In a stem cell–like fashion, selected T cells must balance mutually opposing demands of differentiation and self-renewal. Activating versus inhibitory signals to T cells instruct opposing cell metabolism, linked to alternative cell fates that arise in sibling cells through lopsided information transfer. Emerging studies indicate that durable immunotherapy response may be limited by the abundance of self-renewing T cells. Leveraging of basic discoveries of regenerative signaling to bolster sustained, stem-like output of freshly differentiated T cells is offering new strategies to overcome cancer immunotherapy resistance. Lymphocyte regeneration may also sustain harmful autoimmune attack. Undercutting the self-renewal of pathogenic clones may thus emerge as a therapeutic strategy for autoimmune diseases.

Authors

Steven L. Reiner

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Commentaries
Abstract

Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancer, presents a clinical challenge in developing effective treatment options. In this issue of the JCI, Zeng et al. demonstrate a provocative and promising therapeutic strategy for TNBC by leveraging the metabolic vulnerabilities presented by methylthioadenosine phosphorylase (MTAP) deletion to genotoxic stress inducers, such as poly (ADP-ribose) polymerase inhibitors (PARPi). They found that combining MTAP deletion or inhibition with PARPi was highly effective in brain metastatic TNBC where the methionine-limited environment further enhanced this combination. This approach underscores the importance of targeting metabolic vulnerabilities in the development of personalized cancer therapies.

Authors

Samyuktha Suresh, James M. Ford

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Abstract

Recent studies have highlighted a possible role for gut microbiota in modulating Alzheimer’s disease pathology, particularly through the actions of gut-derived metabolites and their influence on the immune system. In this issue of the JCI, Chandra et al. reveal that circulating levels of the gut microbiota–derived metabolite propionate affected amyloid burden and glial activation in a mouse model of Aβ amyloidosis. The study also identifies a mechanism for the therapeutic benefit of propionate supplementation, showing that propionate lowered peripheral IL-17 and suppressed Th17 cell activity. These results support the idea of therapeutic targeting of the gut/brain/immune axis, particularly via modulation of Th17 responses, and suggest translational strategies involving microbiome-based or immunological interventions for dementia prevention and treatment.

Authors

Wade K. Self, David M. Holtzman

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Research Articles
Abstract

Coinhibitory receptors function as central modulators of the immune response to resolve T effector activation and/or to sustain immune homeostasis. Here, using humanized SCID mice, we found that neuropilin–2 (NRP2) is inducible on late effector and exhausted subsets of human CD4+ T cells and that it is coexpressed with established coinhibitory molecules including PD-1, CTLA4, TIGIT, LAG3, and TIM3. In murine models, we also found that NRP2 is expressed on effector memory CD4+ T cells with an exhausted phenotype and that it functions as a key coinhibitory molecule. Knockout (KO) of NRP2 resulted in hyperactive CD4+ T cell responses and enhanced inflammation in delayed-type hypersensitivity and transplantation models. After cardiac transplantation, allograft rejection and graft failure were accelerated in global as well as CD4+ T cell–specific KO recipients, and enhanced alloimmunity was dependent on NRP2 expression on CD4+ T effectors but not on CD4+Foxp3+ Tregs. Also, KO Tregs were found to be as efficient as WT cells in the suppression of effector responses in vitro and in vivo. These collective findings identify NRP2 as a potentially novel coinhibitory receptor and demonstrate that its expression on CD4+ T effector cells is of great functional importance in immunity.

Authors

Johannes Wedel, Nora Kochupurakkal, Sek Won Kong, Sayantan Bose, Ji-Won Lee, Madeline Maslyar, Bayan Alsairafi, Kayla MacLeod, Kaifeng Liu, Hengcheng Zhang, Masaki Komatsu, Hironao Nakayama, Diane R. Bielenberg, David M. Briscoe

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Abstract

Lymphocyte activation gene 3 (LAG3) is a coinhibitory receptor expressed by various immune cells. Although the immunomodulatory potential of LAG3 is being explored in cancer and autoimmunity, there is no information on its role after organ transplantation. Our study investigated the functions of LAG3 in a mouse model of renal allograft rejection. LAG3–/– recipients rapidly rejected MHC-mismatched renal allografts that were spontaneously accepted by WT recipients, with graft histology characteristic of antibody-mediated rejection. Depletion of recipient B cells but not CD8+ T cells significantly extended kidney allograft survival in LAG3–/– recipients. Treatment of WT recipients with an antagonistic LAG3 antibody enhanced anti-donor immune responses and induced kidney damage associated with chronic rejection. The studies of conditional LAG3–/– recipients and mixed bone marrow chimeras demonstrated that LAG3 expression on either T or B cells is sufficient to regulate anti-donor humoral immunity but not to induce acute allograft rejection. The numbers and proinflammatory functions of graft-infiltrating NK cells were markedly increased in LAG3–/– recipients, suggesting that LAG3 also regulates the effector stage of antibody-mediated rejection. These findings identified LAG3 as a regulator of immune responses to kidney allografts and a potential therapeutic target for antibody-mediated rejection prevention and treatment.

Authors

Michael Nicosia, Ran Fan, Juyeun Lee, Gabriella All, Victoria Gorbacheva, José I. Valenzuela, Yosuke Yamamoto, Ashley Beavers, Nina Dvorina, William M. Baldwin III, Eduardo Chuluyan, Motoo Araki, Brian T. Gaudette, Robert L. Fairchild, Booki Min, Anna Valujskikh

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Abstract

Germinal center (GC) B cells are pivotal in establishing a robust humoral immune response and long-term serological immunity while maintaining antibody self-tolerance. GC B cells rely on autophagy for antigen presentation and homeostatic maintenance. However, these functions, primarily associated with the light zone, cannot explain the spatiotemporal autophagy upregulation in the dark zone of GCs. Here, combining imaging, molecular, and genomic approaches, we defined a functional mechanism controlling chromatin accessibility in GC B cells during their dark zone transition. This mechanism links autophagy and nuclear lamin B1 dynamics with their downstream effects, including somatic hypermutation and antibody affinity maturation. Moreover, the autophagy–lamin B1 axis is highly active in the aberrant ectopic GCs in the salivary glands of Sjögren’s disease, defining its role in autoimmunity.

Authors

Marta C. Sallan, Filip Filipsky, Christina H. Shi, Elena Pontarini, Manuela Terranova-Barberio, Gordon Beattie, Andrew Clear, Michele Bombardieri, Kevin Y. Yip, Dinis Pedro Calado, Mark S. Cragg, Sonya James, Mathew Carter, Jessica Okosun, John G. Gribben, Tanya Klymenko, Andrejs Braun

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Abstract

Complement activation is a relevant driver in the pathomechanisms of vasculitis. The involved proteins in the interaction between endothelia, complement, and platelets in these conditions are only partially understood. Thrombospondin-1 (TSP-1), found in platelet α-granules and released from activated endothelial cells, interacts with factor H (FH) and vWF. However, to our knowledge, direct regulatory interaction with the complement cascade has not yet been described. Our study shows that TSP-1 is a potent, FH-independent inhibitor of the alternative complement pathway. TSP-1 binds to complement proteins and inhibits cleavage of C3 and C5 and the formation of the membrane attack complex. We validated complement-regulatory function in blood samples from patients with primary complement defects. The physiological relevance of TSP-1 was demonstrated in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV) by significantly enhanced TSP-1 staining in glomerular lesions and increased complement activity and NETosis after TSP-1 deficiency in an in vitro and in vivo model of AAV. The complement-inhibiting function of TSP-1 represents an important mechanism in the interaction of endothelia and complement. In particular, the interplay between released TSP-1 and the complement system locally, especially on surfaces, influences the balance between complement activation and inhibition and may be relevant in various vascular diseases.

Authors

Swagata Konwar, Sophie Schroda, Manuel Rogg, Jessika Kleindienst, Eva L. Decker, Martin Pohl, Barbara Zieger, Jens Panse, Hong Wang, Robert Grosse, Christoph Schell, Sabine Vidal, Xiaobo Liu, Christian Gorzelanny, Todor Tschongov, Karsten Häffner

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Abstract

Accumulating evidence implicates the gut microbiome (GMB) in the pathogenesis and progression of Alzheimer’s disease (AD). We recently showed that the GMB regulates reactive astrocytosis and Aβ plaque accumulation in a male APPPS1-21 AD mouse model. Yet, the mechanism(s) by which GMB perturbation alters reactive astrocytosis in a manner that reduces Aβ deposition remain unknown. Here, we performed metabolomics on plasma from mice treated with antibiotics (ABX) and identified a significant increase in plasma propionate, a gut-derived short-chain fatty acid, only in male mice. Administration of sodium propionate reduced reactive astrocytosis and Aβ plaques in APPPS1-21 mice, phenocopying the ABX-induced phenotype. Astrocyte-specific RNA-Seq on ABX- and propionate-treated mice showed reduced expression of proinflammatory and increased expression of neurotrophic genes. Next, we performed flow cytometry experiments, in which we found that ABX and propionate decreased peripheral RAR-related orphan receptor-γ+ (Rorγt+) CD4+ (Th17) cells and IL-17 secretion, which positively correlated with reactive astrocytosis. Last, using an IL-17 mAb to deplete IL-17, we found that propionate reduced reactive astrocytosis and Aβ plaques in an IL-17–dependent manner. Together, these results suggest that gut-derived propionate regulates reactive astrocytosis and Aβ amyloidosis by decreasing peripheral Th17 cells and IL-17 release. Thus, propionate treatment or strategies boosting propionate production may represent novel therapeutic strategies for the treatment of AD.

Authors

Sidhanth Chandra, Jelena Popovic, Naveen K. Singhal, Elyse A. Watkins, Hemraj B. Dodiya, Ian Q. Weigle, Miranda A. Salvo, Abhirami Ramakrishnan, Zhangying Chen, Thomas Watson, Aashutosh Shetti, Natalie Piehl, Xiaoqiong Zhang, Leah Cuddy, Katherine R. Sadleir, Steven J. Schwulst, Murali Prakriya, David Gate, Sangram S. Sisodia, Robert Vassar

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Abstract

The activated JAK2/STAT pathway is characteristic of myeloproliferative neoplasms (MPNs). The pleckstrin 2 (PLEK2) signalosome is downstream of the JAK2/STAT5 pathway and plays an important role in MPN development. The detailed molecular composition of this signalosome is unclear. Here, we reveal peptidylprolyl isomerase-like 2 (PPIL2) as a critical component of the complex in regulating human and murine erythropoiesis. PPIL2 was a direct target of STAT5 and was upregulated in patients with MPN and in a Jak2V617F MPN mouse model. Mechanistically, PPIL2 interacted with and catalyzed p53 polyubiquitination and proteasome-mediated degradation to promote cell growth. Ppil2 deficiency, or inhibition by cyclosporin A, led to a marked upregulation of p53 in vivo and ameliorated myeloproliferative phenotypes in Jak2V617F mice. Cyclosporin A also markedly reduced JAK2-mutated erythroid and myeloid proliferation in an induced pluripotent stem cell–derived human bone marrow organoid model. Our findings reveal PPIL2 as a critical component of the PLEK2 signalosome in driving MPN pathogenesis through negative regulation of p53, thus providing a target and opportunity for drug repurposing using cyclosporin A to treat MPNs.

Authors

Pan Wang, Xu Han, Kehan Ren, Ermin Li, Honghao Bi, Inci Aydemir, Madina Sukhanova, Yijie Liu, Jing Yang, Peng Ji

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Abstract

Phenylketonuria (PKU), an inborn error of phenylalanine (Phe) metabolism, is a common cause of intellectual disability. However, the mechanisms by which elevated Phe levels cause cognitive impairment remain unclear. Here, we show that submillimolar Phe perturbs synaptic plasticity through the hyperactivation of GluN2B-containing NMDARs. PahEnu2 PKU model mice exhibited submillimolar and supramillimolar concentrations of Phe in the cerebrospinal fluid (CSF) and serum, respectively. l-Phe produced concentration-dependent bidirectional effects on NMDA-induced currents, without affecting synaptic NMDA receptors (NMDARs) in hippocampal CA1 neurons. l-Phe-induced hyperactivation of extrasynaptic GluN2B resulted in activity-dependent downregulation of AMPA receptors during burst or sustained synaptic activity. Administration of l-Phe in mice decreased neural activity and impaired memory, which were blocked by pretreatment with GluN2B inhibitors. Furthermore, pharmacological and virus-mediated suppression of GluN2B reversed the impaired learning in PahEnu2 mice. Collectively, these results suggest the concentration of Phe in the CSF of patients with PKU perturbs extrasynaptic NMDARs and synaptic plasticity and that suppression of GluN2B may have the potential to improve cognitive function in patients with PKU.

Authors

Woo Seok Song, Young Sook Kim, Young-Soo Bae, Sang Ho Yoon, Jae Min Lim, Myoung-Hwan Kim

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Abstract

In preclinical mouse models of triple-negative breast cancer (TNBC), we show that a combination of chemotherapy with cisplatin (CDDP) and eribulin (Eri) was additive from an immunological point of view and was accompanied by the induction of an intratumoral immune and inflammatory response favored by the immunogenic cell death induced by CDDP, as well as by the vascular and tumor stromal remodeling induced by each chemotherapy. Unexpectedly, despite the favorable immune context created by this immunomodulatory chemotherapy combination, our models remained refractory to the addition of anti–PD-L1 immunotherapy. These surprising observations led us to discover that CDDP chemotherapy was simultaneously responsible for the production of TGF-β by several populations of cells present in tumors, which favored the emergence of different subpopulations of immune cells and cancer-associated fibroblasts characterized by immunosuppressive properties. Accordingly, co-treatment with anti–TGF-β restored the immunological synergy between this immunogenic doublet of chemotherapy and anti–PD-L1 in a CD8-dependent manner. Translational studies revealed the unfavorable prognostic effect of the TGF-β pathway on the immune response in human TNBC, as well as the ability of CDDP to induce this cytokine also in human TNBC cell lines, thus highlighting the clinical relevance of targeting TGF-β in the context of human TNBC treated with chemoimmunotherapy.

Authors

Laura Kalfeist, Fanny Ledys, Stacy Petit, Cyriane Poirrier, Samia Kada Mohammed, Loïck Galland, Valentin Derangère, Alis Ilie, David Rageot, Romain Aucagne, Pierre-Simon Bellaye, Caroline Truntzer, Marion Thibaudin, Mickaël Rialland, François Ghiringhelli, Emeric Limagne, Sylvain Ladoire

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Abstract

Sustaining the strong rhythmic interactions between cellular adaptations and environmental cues has been posited as essential for preserving the physiological and behavioral alignment of an organism to the proper phase of the daily light/dark (LD) cycle. Here, we demonstrate that mitochondria and synaptic input organization of suprachiasmatic (SCN) vasoactive intestinal peptide–expressing (VIP-expressing) neurons showed circadian rhythmicity. Perturbed mitochondrial dynamics achieved by conditional ablation of the fusogenic protein mitofusin 2 (Mfn2) in VIP neurons caused disrupted circadian oscillation in mitochondria and synapses in SCN VIP neurons, leading to desynchronization of entrainment to the LD cycle in Mfn2-deficient mice that resulted in an advanced phase angle of their locomotor activity onset, alterations in core body temperature, and sleep-wake amount and architecture. Our data provide direct evidence of circadian SCN clock machinery dependence on high-performance, Mfn2-regulated mitochondrial dynamics in VIP neurons for maintaining the coherence in daily biological rhythms of the mammalian organism.

Authors

Milan Stoiljkovic, Jae Eun Song, Hee-kyung Hong, Heiko Endle, Luis Varela, Jonatas Catarino, Xiao-Bing Gao, Zong-Wu Liu, Peter Sotonyi, Sabrina Diano, Jonathan Cedernaes, Joseph T. Bass, Tamas L. Horvath

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Abstract

Chagas disease, caused by Trypanosoma cruzi, is endemic to Latin America and is characterized by chronic inflammation of cardiac tissues due to parasite persistence. Hypoxia within infected tissues may trigger the stabilization of HIF-1 and be linked to ATP release. Extracellular ATP exhibits microbicidal effects but is scavenged by CD39 and CD73 ectonucleotidases, which ultimately generate adenosine (ADO), a potent immunosuppressor. Here, we comprehensively study the importance of HIF-1 stabilization and the CD39/CD73/ADO axis, on CD4+ T cells with the cytotoxic phenotype, in facilitating the persistence of T. cruzi. Myocardial infection induces prominent areas of hypoxia, which is concomitant with HIF-1α stabilization in T cells and linked to early expansion of CD39+CD73+CD4+ T cell infiltrating population. Functional assays further demonstrate that HIF-1 stabilization and CD73 activity are associated with impaired CD4+ T cell cytotoxic potential. RNA-Seq analysis reveals that HIF-1 and purinergic signaling pathways are overrepresented in cardiac tissues of patients with end-stage Chagas disease. The findings highlight a major effect of purinergic signaling on CD4+ T cells with potential cytotoxic capacity in the setting of T. cruzi infection and have translational implications for therapy.

Authors

Gastón Bergero, Yanina L. Mazzocco, Sebastian Del Rosso, Ruining Liu, Zoé M. Cejas Gallardo, Simon C. Robson, Martin Rottenberg, Maria P. Aoki

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Abstract

Stem-like T cells selectively contribute to autoimmunity, but the activities that promote their pathogenicity are incompletely understood. Here, we identify the transcription coregulator OCA-B as a driver of the pathogenic maturation of stem-like CD4+ T cells to promote autoimmune demyelination. Using 2 human multiple sclerosis (MS) datasets, we show that POU2AF1, the gene encoding OCA-B, is elevated in CD4+ T cells from patients with MS. We show that T cell–intrinsic OCA-B loss protects mice from experimental autoimmune encephalomyelitis (EAE) while preserving responses to viral CNS infection. In EAE models driven by antigen re-encounter, OCA-B deletion nearly eliminates CNS infiltration, proinflammatory cytokine production, and clinical disease. OCA-B–expressing CD4+ T cells of mice primed with autoantigen express an encephalitogenic gene program and preferentially confer disease. In a relapsing-remitting EAE model, OCA-B loss protects mice specifically at relapse. During remission, OCA-B promotes the expression of Tcf7, Slamf6, and Sell in proliferating CNS T cell populations. At relapse time points, OCA-B loss results in both the accumulation of an immunomodulatory CD4+ T cell population expressing Ccr9 and Bach2, and loss of proinflammatory gene expression from Th17 cells. These results identify OCA-B as a driver of pathogenic CD4+ T cells.

Authors

Erik P. Hughes, Amber R. Syage, Elnaz Mirzaei Mehrabad, Thomas E. Lane, Benjamin T. Spike, Dean Tantin

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Abstract

Triple-negative breast cancer (TNBC) represents the most malignant subtype of breast cancer. The clinical application of PARP inhibitors (PARPi) is limited by the low frequency of BRCA1/2 mutations in TNBC. Here, we identified that MTAP deletion sensitized genotoxic agents in our clinical cohort of metastatic TNBC. Further study demonstrated that MTAP deficiency or inhibition rendered TNBC susceptibility to chemotherapeutic agents, particularly PARPi. Mechanistically, targeting MTAP that synergized with PARPi by disrupting the METTL16-MAT2A axis involved in methionine metabolism and depleting in vivo s-adenosylmethionine (SAM) levels. Exhausted SAM in turn impaired PARPi-induced DNA damage repair through attenuation of MRE11 recruitment and end resection by diminishing MRE11 methylation. Notably, brain metastatic TNBC markedly benefited from a lower dose of PARPi and MTAP deficiency/inhibition synergy due to the inherently limited methionine environment in the brain. Collectively, our findings revealed a feed-forward loop between methionine metabolism and DNA repair through SAM, highlighting a therapeutic strategy of PARPi combined with MTAP deficiency/inhibition for TNBC.

Authors

Xiangyu Zeng, Fei Zhao, Xinyi Tu, Yong Zhang, Wen Yang, Jing Hou, Qi Jiang, Shouhai Zhu, Zheming Wu, Yalan Hao, Lingxin Zhang, Richard M. Weinshilboum, Kaixiong Tao, Liewei Wang, Zhenkun Lou

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Abstract

Alcohol-associated liver disease represents a significant global health challenge, with gut microbial dysbiosis and bacterial translocation playing a critical role in its pathogenesis. Patients with alcohol-associated hepatitis had increased fecal abundance of mammalian viruses, including retroviruses. This study investigated the role of endogenous retroviruses (ERVs) in the development of alcohol-associated liver disease. Transcriptomic analysis of duodenal and liver biopsies revealed increased expression of several human ERVs, including HERV-K and HERV-H, in patients with alcohol-associated liver disease compared with individuals acting as controls. Chronic-binge ethanol feeding markedly induced ERV abundance in intestinal epithelial cells but not the livers of mice. Ethanol increased ERV expression and activated the Z-DNA binding protein 1 (Zbp1)–mixed lineage kinase domain-like pseudokinase (Mlkl) signaling pathways to induce necroptosis in intestinal epithelial cells. Antiretroviral treatment reduced ethanol-induced intestinal ERV expression, stabilized the gut barrier, and decreased liver disease in microbiota-humanized mice. Furthermore, mice with an intestine-specific deletion of Zbp1 were protected against bacterial translocation and ethanol-induced steatohepatitis. These findings indicate that ethanol exploits this pathway by inducing ERVs and promoting innate immune responses, which results in the death of intestinal epithelial cells, gut barrier dysfunction, and liver disease. Targeting the ERV/Zbp1 pathway may offer new therapies for patients with alcohol-associated liver disease.

Authors

Noemí Cabré, Marcos F. Fondevila, Wenchao Wei, Tomoo Yamazaki, Fernanda Raya Tonetti, Alvaro Eguileor, Ricard Garcia-Carbonell, Abraham S. Meijnikman, Yukiko Miyamoto, Susan Mayo, Yanhan Wang, Xinlian Zhang, Thorsten Trimbuch, Seija Lehnardt, Lars Eckmann, Derrick E. Fouts, Cristina Llorente, Hidekazu Tsukamoto, Peter Stärkel, Bernd Schnabl

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Abstract

The ATP6V0A4 gene encodes the a4 subunit of vacuolar H+-ATPase (V-ATPase), which mediates hydrogen ion transport across the membrane. Previous studies have suggested that mutations in ATP6V0A4 consistently result in a loss of function, impairing the hydrogen ion transport efficacy of V-ATPase and leading to distal renal tubular acidosis and sensorineural hearing loss. Here, we identified a 32-year-old male patient and his father, both of whom harbored a heterozygous ATP6V0A4 p.V512L mutation and exhibited hypochloremic metabolic alkalosis, acidic urine, and hypokalemia. Through a series of protein structural analyses and functional experiments, the V512L mutation was confirmed as a gain-of-function mutation in the ATP6V0A4 gene. V512-a4 increased a4 subunit expression abundance by enhancing V512L-a4 stability and reducing its degradation, which in turn potentiated the capacity of V-ATPase to acidify the tubular lumen, leading to acidic urine and metabolic alkalosis. Through mutant V512L-a4 subunit structure-based virtual and experimental screening, we identified F351 (C25H26FN3O2S), a small-molecule inhibitor specifically targeting the V512L-a4 mutant. In conclusion, we identified a gain-of-function mutation in the ATP6V0A4 gene, broadening its phenotypic and mutational spectrum, and we provide valuable insights into potential therapeutic approaches for diseases associated with ATP6V0A4 mutations.

Authors

Si-qi Peng, Qian-qian Wu, Wan-yi Wang, Yi-Lin Zhang, Rui-ning Zhou, Jun Liao, Jin-xuan Wei, Yan Yang, Wen Shi, Jun-lan Yang, Xiao-xu Wang, Zhi-yuan Wei, Jia-xuan Sun, Lu Huang, Hong Fan, Hui Cai, Cheng-kun Wang, Xin-hua Li, Ting-song Li, Bi-cheng Liu, Xiao-liang Zhang, Bin Wang

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Abstract

Neurofibromatosis type 1 (NF1) is a genetic disorder caused by mutations of the NF1 tumor suppressor gene resulting in the loss of function of neurofibromin, a GTPase-activating protein (GAP) for Ras. While the malignant manifestations of NF1 are associated with loss of heterozygosity of the residual WT allele, the nonmalignant neurodevelopmental sequelae, including autism spectrum disorder (ASD) and/or attention deficit hyperactivity disorder (ADHD) are prevalent morbidities that occur in the setting of neurofibromin haploinsufficiency. We reasoned that augmenting endogenous levels of WT neurofibromin could serve as a potential therapeutic strategy to correct the neurodevelopmental manifestations of NF1. Here, we used a combination of genetic screening and genetically engineered murine models to identify a role for the F-box protein FBXW11 as a regulator of neurofibromin degradation. Disruption of Fbxw11, through germline mutation or targeted genetic manipulation in the nucleus accumbens, increased neurofibromin levels, suppressed Ras-dependent ERK phosphorylation, and corrected social learning deficits and impulsive behaviors in male Nf1+/– mice. Our results demonstrate that preventing the degradation of neurofibromin is a feasible and effective approach to ameliorate the neurodevelopmental phenotypes in a haploinsufficient disease model.

Authors

Su Jung Park, Jodi L. Lukkes, Ka-Kui Chan, Hayley P. Drozd, Callie B. Burgin, Shaomin Qian, Morgan McKenzie Sullivan, Cesar Gabriel Guevara, Nolen Cunningham, Stephanie Arenas, Makenna A. Collins, Jacob Zucker, JinHee Won, Abbi Smith, Li Jiang, Dana K. Mitchell, Steven D. Rhodes, Steven P. Angus, D. Wade Clapp

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Abstract

Anemia is the primary clinical manifestation of myelodysplastic syndromes (MDSs), 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 activin receptor 2B (ACVR2B), its ligand growth and differentiation factor 11 (GDF11), and an effector, SMAD2, are upregulated in samples of patients with MDS. 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 the 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 with nonresponders. Moreover, the increase in RBCs after treatment was linked to a relative decrease in GATA1s isoforms. 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

BACKGROUND Treatment of tubo-ovarian high-grade serous carcinoma (HGSC) includes cytoreductive surgery, platinum-based chemotherapy, and often poly(ADP-ribose) polymerase (PARP) inhibitors. While homologous recombination (HR) deficiency is a well-established predictor of therapy sensitivity, over 50% of HR-proficient HGSCs also exhibit sensitivity. Currently, there are no biomarkers to identify which HR-proficient HGSCs will be sensitive to standard-of-care therapy. Replication stress may serve as a key determinant of response.METHODS We evaluated phospho–RPA2-T21 (p-RPA2) foci via immunofluorescence as a biomarker of replication stress in formalin-fixed, paraffin-embedded HGSC samples collected at diagnosis from patients treated with platinum chemotherapy (discovery cohort, n = 31; validation cohort, n = 244) or PARP inhibitors (n = 63). Recurrent HGSCs (n = 38) were also analyzed. p-RPA2 score was calculated using automated imaging analysis.RESULTS Samples were defined as p-RPA2-high if more than 16% of cells had ≥2 p-RPA2 foci on automated analysis. In the discovery cohort, HR-proficient, p-RPA2-high HGSCs demonstrated significantly higher rates of a chemotherapy response score of 3 to platinum chemotherapy than HR-proficient, p-RPA2-low HGSCs. In the validation cohort, patients with HR-proficient, p-RPA2-high HGSCs had significantly longer survival after platinum treatment than those with HR-proficient, p-RPA2-low HGSCs. Additionally, the p-RPA2 assay effectively predicted survival outcomes in patients treated with PARP inhibitors and in recurrent HGSC samples.CONCLUSION Our study underscores the importance of considering replication stress markers, such as p-RPA2, alongside HR status in therapeutic planning. This approach has the potential to increase the number of patients receiving effective therapy while reducing unnecessary toxicity.FUNDING The Reproductive Scientist Development Program, GOG Foundation, Pilot Translational and Clinical Studies function of the Washington University Institute of Clinical and Translational Sciences, the Foundation for Barnes-Jewish Hospital, Washington University School of Medicine Dean’s Scholar Program, The Cancer Biology Pathway Training Grant (5T32CA113275-17), The Lucy, Anarcha, and Betsey (L.A.B.) Award from the Department of Obstetrics and Gynecology at Washington University School of Medicine, and Veterans Affairs Office of Research and Development (I01BX006020).

Authors

Angela Schab, Amanda Compadre, Rebecca Drexler, Megan Loeb, Kevin Rodriguez, Joshua Brill, Shariska Harrington, Carmen Sandoval, Brooke Sanders, Lindsay Kuroki, Carolyn McCourt, Andrea R. Hagemann, Premal Thaker, David Mutch, Matthew Powell, Violeta Serra, Ian S. Hagemann, Ann E. Walts, Beth Y. Karlan, Sandra Orsulic, Katherine C. Fuh, Lulu Sun, Priyanka Verma, Elena Lomonosova, Peinan Zhao, Dineo Khabele, Mary M. Mullen

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Abstract

Synovial sarcoma is an aggressive soft-tissue cancer driven by the chimeric SS18::SSX fusion oncoprotein, which disrupts chromatin remodeling by combining two antagonistic transcriptional regulators. SS18 participates in BAF complexes that open chromatin, while the SSX genes are cancer-testis antigens that interface with chromatin decorated with monoubiquitinated histone H2A placed by polycomb repressive complex activity. Because KDM2B brings polycomb repressive complex to unmethylated CpG islands, it is plausible that methylation directly determines the distribution of SS18::SSX to target loci. Given that synovial sarcoma is also characterized by a peculiarly low DNA hypomethylation profile, we hypothesized that further disturbance of DNA methylation would have a negative impact on synovial sarcoma growth. DNMT1 disruption by CRISPR/Cas9 targeting or pharmacological inhibition with cytidine analogs 5-aza-2′-deoxycytidine (decitabine) and 5-azacytidine led to decreased genome-wide methylation, redistribution of SS18::SSX, and altered gene expression profiles, most prominently including upregulation of tumor suppressor genes, immune-related genes, and mesenchymal differentiation-related genes. These drugs suppressed growth of synovial sarcoma cell lines and drove cytoreduction in mouse genetic models. DNMT1 inhibitors, already approved for treating myelodysplastic syndromes, warrant further clinical investigation for synovial sarcoma as repurposed, targeted treatments exploiting a vulnerability in the intrinsic biology of this cancer.

Authors

Nobuhiko Hasegawa, Nezha S. Benabdallah, Kyllie Smith-Fry, Li Li, Sarah McCollum, Jinxiu Li, Caelen A. Jones, Lena Wagner, Vineet Dalal, Viola Golde, Anastasija Pejkovska, Lara Carroll, Malay Haldar, Seth M. Pollack, Scott W. Lowe, Torsten O. Nielsen, Ana Banito, Kevin B. Jones

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Corrigendum
Abstract

Authors

Mahesh Raundhal, Christina Morse, Anupriya Khare, Timothy B. Oriss, Jadranka Milosevic, John Trudeau, Rachael Huff, Joseph Pilewski, Fernando Holguin, Jay Kolls, Sally Wenzel, Prabir Ray, Anuradha Ray

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Abstract

Tumor-associated macrophages (TAMs) are abundant in the tumor microenvironment (TME) and dampen the immune response, negatively affecting patient survival. Therefore, targeting TAMs could address the limitations of current cancer treatments. However, drug development in this area remains limited. The Leukocyte-associated Immunoglobulin-like Receptor-1 (LAIR1), also called CD305, is prominently expressed on the surface of TAMs. We have uncovered a previously unrecognized immunosuppressive LAIR1 → Factor XIII A (FXIII-A) → Collagen IV pathway across various cancer types. Inhibition of LAIR1, either through knockout (Lair1–/–), antibody blockade (aLAIR1), or a chimeric antigen receptor (CAR) design (3-in-1 CAR by combining tumor targeting, T cell trafficking, and remodeling of the immunosuppressive TME in one CAR construct) provides enhanced antitumor response. LAIR1 inhibition enhances peripheral and intratumoral CD8 memory T-cell populations, induces a phenotypic shift of M2-like Macrophages towards M1, and normalizes tumor collagen IV and structural components in the TME, facilitating effective tumor-T cell interactions and tumor suppression. Enhanced antitumor responses were observed when Lair1–/– or aLAIR1 was used alone or combined with CAR T cells or when the 3-in-1 CAR T cells were used solely in chemotherapy-radiation-PD-1 blockade-resistant tumor models. These findings position LAIR1 inhibition as a promising strategy for cancer immunotherapies.

Authors

Haipeng Tao, Dongjiang Chen, Changlin Yang, Duy T. Nguyen, Georges Abboud, Ruixuan Liu, Tianyi Liu, Avirup Chakraborty, Alicia Y. Hou, Nicole A. Petit, Muhammad Abbas, Robert W. Davis, Janie Zhang, Christina Von Roemeling, Mohammed O. Gbadamosi, Linchun Jin, Tongjun Gu, Tuo Lin, Pengchen Wang, Alfonso Pepe, Diego Ivan Pedro, Hector R. Mendez-Gomez, Chao Xie, Aida Karachi, Frances Weidert, Dan Jin, Chenggang Wang, Kaytora Long-James, Elizabeth K. Molchan, Paul Castillo, John A. Ligon, Ashley P. Ghiaseddin, Elias J. Sayour, Maryam Rahman, Loic P. Deleyrolle, Betty Y.S. Kim, Duane A. Mitchell, W. Gregory Sawyer, Jianping Huang

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Abstract

Facioscapulohumeral muscular dystrophy (FSHD) is a genetic muscle disease caused by ectopic expression of the toxic protein DUX4, resulting in muscle weakness. However, the mechanism by which DUX4 exerts its toxicity remains unclear. In this study, we observed abnormal iron accumulation in muscles of patients with FSHD and in muscle-specific DUX4-expressing (DUX4-Tg) mice. Treatment with iron chelators, an iron-deficient diet, and genetic modifications inhibiting intracellular uptake of iron did not improve but rather exacerbated FSHD pathology in DUX4-Tg mice. Unexpectedly, however, iron supplementation, either from a high-iron diet or intravenous iron administration, resulted in remarkable improvement in grip strength and running performance in DUX4-Tg mice. Iron supplementation suppressed abnormal iron accumulation and the ferroptosis-related pathway involving increased lipid peroxidation in DUX4-Tg muscle. Muscle-specific DUX4 expression led to retinal vasculopathy, a part of FSHD pathology, which was prevented by iron administration. Furthermore, high-throughput compound screening of the ferroptosis pathway identified drug candidates including Ferrostatin-1 (Fer-1), a potent inhibitor of lipid peroxidation. Treatment with Fer-1 dramatically improved physical function in DUX4-Tg mice. Our findings demonstrate that DUX4-provoked toxicity is involved in the activation of the ferroptosis-related pathway and that supplementary iron could be a promising and readily available therapeutic option for FSHD.

Authors

Kodai Nakamura, Huascar-Pedro Ortuste-Quiroga, Naoki Horii, Shin Fujimaki, Toshiro Moroishi, Keiichi I. Nakayama, Shinjiro Hino, Yoshihiko Saito, Ichizo Nishino, Yusuke Ono

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Abstract

Elevated cholesterol poses cardiovascular risks. The glucocorticoid receptor (GR) harbors a still undefined role in cholesterol regulation. Here, we report that a coding single nucleotide polymorphism (SNP) in the gene en-coding the GR, rs6190, associated with increased cholesterol in women according to UK Biobank and All Of Us datasets. In SNP-genocopying mice, we found that the SNP enhanced hepatic GR activity to transactivate Pcsk9 and Bhlhe40, negative regulators of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) re-ceptors respectively. In mice, the SNP was sufficient to elevate circulating cholesterol across all lipoprotein frac-tions and the risk and severity of atherosclerotic lesions on the pro-atherogenic hAPOE*2/*2 background. The SNP effect on atherosclerosis was blocked by in vivo liver knockdown of Pcsk9 and Bhlhe40. Also, corti-costerone and testosterone were protective against the mutant GR program in cholesterol and atherosclerosis in male mice, while the SNP effect was additive to estrogen loss in females. Remarkably, we found that the mu-tant GR program was conserved in human hepatocyte-like cells using CRISPR-engineered, SNP-genocopying human induced pluripotent stem cells (hiPSCs). Taken together, our study leverages a non-rare human variant to uncover a novel GR-dependent mechanism contributing to atherogenic risk, particularly in women.

Authors

Hima Bindu Durumutla, April Haller, Greta Noble, Ashok Daniel Prabakaran, Kevin McFarland, Hannah Latimer, Akanksha Rajput, Olukunle Akinborewa, Bahram Namjou-Khales, David Y. Hui, Mattia Quattrocelli

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Abstract

Authors

James G. Krueger, Mrinal K. Sarkar, Mark G. Lebwohl, Akimichi Morita, Kenneth Gordon, Rachael Bogle, Christopher Cole, Anthony Coon, Richard G. Langley, Richard B. Warren, Arash Mostaghimi, Bruce Strober, A. David Burden, Min Zheng, Aaron R. Mangold, Milan J. Anadkat, Jonathan N. Barker, Joseph F. Merola, Lam C. Tsoi, Ming Tang, Kolja Becker, Denis Delic, Christian Thoma, Johann E. Gudjonsson

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Abstract

Neuropathic pain is often comorbid with affective disorders. Synaptic plasticity in anterior cingulate cortex (ACC) is assumed to be a crucial interface for pain perception and emotion. Laminin β1 (LAMB1), a key element of extracellular matrix (ECM) in ACC was recently revealed to convey extracellular alterations to intracellular synaptic plasticity and underlie neuropathic pain and aversive emotion. However, it remains elusive what triggers activity-dependent changes of LAMB1 and ECM remodeling after nerve injury. Here, we uncovered a key role of retinoic acid (RA)/RARB signaling in neuropathic pain and associated anxiodepression via regulation of ECM homeostasis. We showed that nerve injury reduced RA level in the serum and ACC in mice and human, which brought about downregulation of its corresponding receptor, RARB. Overexpressing RARB relieved pain hypersensitivity and comorbid anxiodepression, while silencing RARB exacerbated pain sensitivity and induced anxiodepression. Further mechanistic analysis revealed that RARB maintained ECM homeostasis via transcriptional regulation of LAMB1, reversing abnormal synaptic plasticity and eventually improved neuropathic pain and aversive emotion. Taken together with our previous study, we revealed an intracellular-extracellular-intracellular feedforward regulatory network in modulating pain plasticity. Moreover, we identified cingulate RA/RARB signaling as a promising therapeutic target for treatment of neuropathic pain and associated anxiodepression.

Authors

Zhen-Zhen Li, Wan-Neng Liu, Ke-Xin Liu, Zhi-Wei Dou, Rui Zhao, Yun Chen, Meng-Meng Wang, Tao-Zhi Wang, Fei Wang, Wen-Juan Han, Wen-Guang Chu, Xing-Xing Zheng, Rou-Gang Xie, Hua Yuan, Xiao-Fan Jiang, Xiao-Long Sun, Ceng Luo, Shengxi Wu

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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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