Issue published April 1, 2025 Previous issue

On the cover: Protein aggregation in the post–myocardial infarction myocardium

Islam, Rawnsley, and colleagues report that phosphorylation of CRYAB, a cardiac myocyte–enriched chaperone protein, after myocardial infarction promotes protein aggregates and contributes to heart failure. The cover image depicts abnormal condensates driven by phosphorylated CRYAB (blue on red) molecules that trap desmin (yellow) to form aggregates. This prevents the physiologic localization of desmin as a scaffold holding linear arrays of sarcomeres (pink) together, causing sarcomere disarray and cardiomyopathy. Image credit: Anthony Bartley.

Conversations with Giants in Medicine
Abstract

Authors

Ushma S. Neill

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Review Series Viewpoint
Review Series
Abstract

Metabolic dysfunction–associated steatotic liver disease (MASLD) is a major cause of liver disease worldwide, and our understanding of its pathogenesis continues to evolve. MASLD progresses from steatosis to steatohepatitis, fibrosis, and cirrhosis, and this Review explores how the gut microbiome and their metabolites contribute to MASLD pathogenesis. We explore the complexity and importance of the intestinal barrier function and how disruptions of the intestinal barrier and dysbiosis work in concert to promote the onset and progression of MASLD. The Review focuses on specific bacterial, viral, and fungal communities that impact the trajectory of MASLD and how specific metabolites (including ethanol, bile acids, short chain fatty acids, and other metabolites) contribute to disease pathogenesis. Finally, we underscore how knowledge of the interaction between gut microbes and the intestinal barrier may be leveraged for MASLD microbial-based therapeutics. Here, we include a discussion of the therapeutic potential of prebiotics, probiotics, postbiotics, and microbial-derived metabolites.

Authors

Bernd Schnabl, Christopher J. Damman, Rotonya M. Carr

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Abstract

Metabolic dysfunction–associated steatotic liver disease (MASLD) is characterized by increased hepatic steatosis with cardiometabolic disease and is a leading cause of advanced liver disease. We review here the genetic basis of MASLD. The genetic variants most consistently associated with hepatic steatosis implicate genes involved in lipoprotein input or output, glucose metabolism, adiposity/fat distribution, insulin resistance, or mitochondrial/ER biology. The distinct mechanisms by which these variants promote hepatic steatosis result in distinct effects on cardiometabolic disease that may be best suited to precision medicine. Recent work on gene-environment interactions has shown that genetic risk is not fixed and may be exacerbated or attenuated by modifiable (diet, exercise, alcohol intake) and nonmodifiable environmental risk factors. Some steatosis-associated variants, notably those in patatin-like phospholipase domain-containing 3 (PNPLA3) and transmembrane 6 superfamily member 2 (TM6SF2), are associated with risk of developing adverse liver-related outcomes and provide information beyond clinical risk stratification tools, especially in individuals at intermediate to high risk for disease. Future work to better characterize disease heterogeneity by combining genetics with clinical risk factors to holistically predict risk and develop therapies based on genetic risk is required.

Authors

Vincent L. Chen, Annapurna Kuppa, Antonino Oliveri, Yanhua Chen, Prabhu Ponnandy, Puja B. Patel, Nicholette D. Palmer, Elizabeth K. Speliotes

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Editor's note
Commentaries
Abstract

Glioblastoma (GBM), the most aggressive type of primary brain tumor, continues to defy therapeutic advances with its metabolic adaptability and resistance to treatment. In this issue of the JCI, Zeng et al. delve into a pivotal mechanism underpinning this adaptability. They identified an important role for TNF receptor–associated factor 3 (TRAF3) in regulating lipid metabolism through its interaction with enoyl-CoA hydratase 1 (ECH1). These findings elucidate a unique signaling axis that shields GBM cells from lipid peroxidation and antitumor immunity, advancing therapeutic strategies for GBM that may also carry over to other cancers with similar metabolic vulnerabilities.

Authors

Tzu-Yi Chia, Nishanth S. Sadagopan, Jason Miska

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Abstract

Non–small cell lung cancer (NSCLC), the most common type of lung cancer, remains a leading cause of cancer-related mortality worldwide. Immune checkpoint inhibitors (ICIs) have emerged as a promising therapy for NSCLC but only benefit a subset of patients. In this issue of the JCI, Jiao et al. revealed that acetyl-CoA acetyltransferase 1 (ACAT1) limited the efficacy of ICIs in NSCLC by impeding tertiary lymphoid structures (TLS) in the tumor microenvironment (TME). Targeting ACAT1 in tumor cells reduced mitochondrial hypersuccinylation and oxidative stress, enhancing TLS abundance and improving the efficacy of ICIs in preclinical murine models of NSCLC.

Authors

Sophie O’Keefe, Qiwei Wang

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Abstract

Nucleoporin 98 (NUP98) fusion oncogenes are known to promote aggressive pediatric leukemia by disrupting chromatin structure and modulating the expression of homeobox (HOX) genes, yet the precise molecular events are unclear. In this issue of the JCI, K. Hamamoto et al. explore the mechanistic underpinnings of NUP98 fusion–driven pediatric leukemia, with a focus on aberrant activation of the Hoxb-associated long, noncoding RNA (lncRNA) HoxBlinc. The authors provide compelling evidence that HoxBlinc plays a central role in the oncogenic transformation associated with NUP98 fusion protein. The study underscores a CTCF-independent role of HoxBlinc in the regulation of topologically associated domains (TADs) and chromatin accessibility, which has not been fully appreciated in previous research on the NUP98 fusion oncogenes. The discovery of HoxBlinc lncRNA as a downstream regulator of NUP98 fusion oncoproteins offers a potential target for therapeutic intervention in pediatric leukemia.

Authors

Jian Xu, Wei Du

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Abstract

Metabolic reprogramming in pancreatic ductal adenocarcinoma (PDAC) fosters an immunosuppressive tumor microenvironment (TME) characterized by elevated lactate levels, which contribute to immune evasion and therapeutic resistance. In this issue of the JCI, Sun, Zhang, and colleagues identified nonhistone ENSA-K63 lactylation as a critical regulator that inactivates PP2A, activates STAT3/CCL2 signaling, recruits tumor-associated macrophages (TAMs), and suppresses cytotoxic T cell activity. Targeting ENSA-K63 lactylation or CCL2/CCR2 signaling reprograms the TME and enhances the efficacy of immune checkpoint blockade (ICB) in PDAC preclinical models. This work provides critical insights into the metabolic-immune crosstalk in PDAC and highlights promising therapeutic strategies for overcoming immune resistance and improving patient outcomes.

Authors

Qun Chen, Hao Yuan, Michael S. Bronze, Min Li

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Abstract

Immune correlates of protection against infection with Mycobacterium tuberculosis (Mtb) remain elusive. In this issue of the JCI, Dallmann-Sauer and authors demonstrate that lack of tuberculin skin test (TST) and interferon γ release assay (IGRA) conversion among people with HIV despite years-long Mtb exposure is associated with alveolar lymphocytosis, including specific poly-cytotoxic T cells, and M1-type alveolar macrophages with a stronger ex vivo response to the pathogen. Studies in these rare individuals, termed “TB resisters” and in tuberculosis household contacts who are repeatedly IGRA negative in the months after a specific exposure event (known as “early clearers”) help elucidate manipulatable mechanisms to boost protection against Mtb infection.

Authors

Todia P. Setiabudiawan, Philip C. Hill, Andrew R. DiNardo, Reinout van Crevel

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Research Articles
Abstract

Protein aggregates are emerging therapeutic targets in rare monogenic causes of cardiomyopathy and amyloid heart disease, but their role in more prevalent heart-failure syndromes remains mechanistically unexamined. We observed mislocalization of desmin and sarcomeric proteins to aggregates in human myocardium with ischemic cardiomyopathy and in mouse hearts with post–myocardial infarction ventricular remodeling, mimicking findings of autosomal-dominant cardiomyopathy induced by the R120G mutation in the cognate chaperone protein CRYAB. In both syndromes, we demonstrate increased partitioning of CRYAB phosphorylated on serine 59 to NP40-insoluble aggregate-rich biochemical fraction. While CRYAB undergoes phase separation to form condensates, the phosphomimetic mutation of serine 59 to aspartate (S59D) in CRYAB mimics R120G-CRYAB mutants with reduced condensate fluidity, formation of protein aggregates, and increased cell death. Conversely, changing serine to alanine (phosphorylation-deficient mutation) at position 59 (S59A) restored condensate fluidity and reduced both R120G-CRYAB aggregates and cell death. In mice, S59D CRYAB knockin was sufficient to induce desmin mislocalization and myocardial protein aggregates, while S59A CRYAB knockin rescued left ventricular systolic dysfunction after myocardial infarction and preserved desmin localization with reduced myocardial protein aggregates. 25-Hydroxycholesterol attenuated CRYAB serine 59 phosphorylation and rescued post–myocardial infarction adverse remodeling. Thus, targeting CRYAB phosphorylation-induced condensatopathy is an attractive strategy to counter ischemic cardiomyopathy.

Authors

Moydul Islam, David R. Rawnsley, Xiucui Ma, Walter Navid, Chen Zhao, Xumin Guan, Layla Foroughi, John T. Murphy, Honora Navid, Carla J. Weinheimer, Attila Kovacs, Jessica Nigro, Aaradhya Diwan, Ryan P. Chang, Minu Kumari, Martin E. Young, Babak Razani, Kenneth B. Margulies, Mahmoud Abdellatif, Simon Sedej, Ali Javaheri, Douglas F. Covey, Kartik Mani, Abhinav Diwan

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Abstract

The osteogenic environment promotes vascular calcium phosphate deposition and aggregation of unfolded and misfolded proteins, resulting in ER stress in chronic kidney disease (CKD). Controlling ER stress through genetic intervention is a promising approach for treating vascular calcification. In this study, we demonstrated a positive correlation between ER stress–induced tribble homolog 3 (TRIB3) expression and progression of vascular calcification in human and rodent CKD. Increased TRIB3 expression promoted vascular smooth muscle cell (VSMC) calcification by interacting with the C2 domain of the E3 ubiquitin-protein ligase Smurf1, facilitating its K48-related self-ubiquitination at Lys381 and Lys383 and subsequent dissociation from the plasma membrane and nuclei. This degeneration of Smurf1 accelerated the stabilization of the osteogenic transcription factors RUNX family transcription factor 2 (Runx2) and SMAD family member 1 (Smad1). C/EBP homologous protein and activating transcription factor 4 are upstream transcription factors of TRIB3 in an osteogenic environment. Genetic KO of TRIB3 or rescue of Smurf1 ameliorated VSMC and vascular calcification by stabilizing Smurf1 and enhancing the degradation of Runx2 and Smad1. Our findings shed light on the vital role of TRIB3 as a scaffold in ER stress and vascular calcification and offer a potential therapeutic option for CKD.

Authors

Yihui Li, Chang Ma, Yanan Sheng, Shanying Huang, Huaibing Sun, Yun Ti, Zhihao Wang, Feng Wang, Fangfang Chen, Chen Li, Haipeng Guo, Mengxiong Tang, Fangqiang Song, Hao Wang, Ming Zhong

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Abstract

Merkel Cell Carcinoma (MCC) is an aggressive neuroendocrine cutaneous malignancy arising from either ultraviolet-induced mutagenesis or Merkel cell polyomavirus (MCPyV) integration. Despite extensive research, our understanding of the molecular mechanisms driving the transition from normal cells to MCC remains limited. To address this knowledge gap, we assessed the impact of inducible MCPyV T antigens on normal human fibroblasts by performing RNA-seq. Our data uncovered changes in expression and regulation of Wnt signaling pathway members. Building on this observation, we bioinformatically evaluated various Wnt pathway perturbagens for their ability to reverse the MCC gene expression signature and identified pyrvinium pamoate, an FDA-approved anthelminthic drug known for its antitumor activity in other cancers. Leveraging transcriptomic, network, and molecular analyses, we found that pyrvinium targets multiple MCC vulnerabilities. Pyrvinium not only reverses the neuroendocrine features of MCC by modulating canonical and noncanonical Wnt signaling but also inhibits cancer cell growth by activating p53-mediated apoptosis, disrupting mitochondrial function, and inducing endoplasmic reticulum stress. Finally, we demonstrated that pyrvinium reduces tumor growth in an MCC mouse xenograft model. These findings offer a deeper understanding of the role of Wnt signaling in MCC and highlight the utility of pyrvinium as a potential treatment for MCC.

Authors

Jiawen Yang, James T. Lim, Paul Victor Santiago Raj, Marcelo G. Corona, Chen Chen, Hunain Khawaja, Qiong Pan, Gillian D. Paine-Murrieta, Rick G. Schnellmann, Denise J. Roe, Prafulla C. Gokhale, James A. DeCaprio, Megha Padi

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Abstract

Glioblastoma (GBM) is a highly aggressive form of brain tumor characterized by dysregulated metabolism. Increased fatty acid oxidation (FAO) protects tumor cells from lipid peroxidation–induced cell death, although the precise mechanisms involved remain unclear. Here, we report that loss of TNF receptor–associated factor 3 (TRAF3) in GBM critically regulated lipid peroxidation and tumorigenesis by controlling the oxidation of polyunsaturated fatty acids (PUFAs). TRAF3 was frequently repressed in GBM due to promoter hypermethylation. TRAF3 interacted with enoyl-CoA hydratase 1 (ECH1), an enzyme that catalyzes the isomerization of unsaturated FAs (UFAs) and mediates K63-linked ubiquitination of ECH1 at Lys214. ECH1 ubiquitination impeded TOMM20-dependent mitochondrial translocation of ECH1, which otherwise promoted the oxidation of UFAs, preferentially the PUFAs, and limited lipid peroxidation. Overexpression of TRAF3 enhanced the sensitivity of GBM to ferroptosis and anti–programmed death–ligand 1 (anti–PD-L1) immunotherapy in mice. Thus, the TRAF3/ECH1 axis played a key role in the metabolism of PUFAs and was crucial for lipid peroxidation damage and immune elimination in GBM.

Authors

Yu Zeng, Liqian Zhao, Kunlin Zeng, Ziling Zhan, Zhengming Zhan, Shangbiao Li, Hongchao Zhan, Peng Chai, Cheng Xie, Shengfeng Ding, Yuxin Xie, Li Wang, Cuiying Li, Xiaoxia Chen, Daogang Guan, Enguang Bi, Jianyou Liao, Fan Deng, Xiaochun Bai, Ye Song, Aidong Zhou

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Abstract

Infantile hemangioma (IH) is the most common tumor in children and a paradigm for pathological vasculogenesis, angiogenesis, and regression. Propranolol, the mainstay of treatment, inhibits IH vessel formation via a β-adrenergic receptor-independent off-target effect of its R(+) enantiomer on endothelial SOX18 - a member of the SOX (SRY-related HMG-box) family of transcription factors. Transcriptomic profiling of patient-derived hemangioma stem cells uncovered the mevalonate pathway (MVP) as a target of R(+) propranolol. Loss and gain of function of SOX18 confirmed it is both necessary and sufficient for R(+) propranolol suppression of the MVP, including regulation of sterol regulatory element–binding protein 2 (SREBP2) and the rate-limiting enzyme HMG-CoA reductase (HMGCR). A biological relevance of the endothelial SOX18-MVP axis in IH patient tissue was demonstrated by nuclear colocalization of SOX18 and SREBP2. Functional validation in a preclinical IH xenograft model revealed that statins — competitive inhibitors of HMGCR — efficiently suppress IH vessel formation. We propose an endothelial SOX18-MVP axis as a central regulator of IH pathogenesis and suggest statin repurposing to treat IH. The pleiotropic effects of R(+) propranolol and statins along the SOX18-MVP axis to disable an endothelial cell–specific program may have therapeutic implications for other vascular disease entities involving pathological vasculogenesis and angiogenesis.

Authors

Annegret Holm, Matthew S. Graus, Jill Wylie-Sears, Jerry Wei Heng Tan, Maya Alvarez-Harmon, Luke Borgelt, Sana Nasim, Long Chung, Ashish Jain, Mingwei Sun, Liang Sun, Pascal Brouillard, Ramrada Lekwuttikarn, Yanfei Qi, Joyce Teng, Miikka Vikkula, Harry Kozakewich, John B. Mulliken, Mathias Francois, Joyce Bischoff

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Abstract

Steatotic liver enhances liver metastasis of colorectal cancer (CRC), but this process is not fully understood. Steatotic liver induced by a high-fat diet increases cancer-associated fibroblast (CAF) infiltration and collagen and hyaluronic acid (HA) production. We investigated the role of HA synthase 2 (HAS2) in the fibrotic tumor microenvironment in steatotic liver using Has2ΔHSC mice, in which Has2 is deleted from hepatic stellate cells. Has2ΔHSC mice had reduced steatotic liver–associated metastatic tumor growth of MC38 CRC cells, collagen and HA deposition, and CAF and M2 macrophage infiltration. We found that low–molecular weight HA activates Yes-associated protein (YAP) in cancer cells, which then releases connective tissue growth factor to further activate CAFs for HAS2 expression. Single-cell analyses revealed a link between CAF-derived HAS2 and M2 macrophages and CRC cells through CD44; these cells were associated with exhausted CD8+ T cells via programmed death–ligand 1 and programmed cell death protein 1 (PD-1). HA synthesis inhibitors reduced steatotic liver–associated metastasis of CRC, YAP expression, and CAF and M2 macrophage infiltration, and improved response to anti–PD-1 antibody. In conclusion, steatotic liver modulates a fibrotic tumor microenvironment to enhance metastatic cancer activity through a bidirectional regulation between CAFs and metastatic tumors, enhancing the metastatic potential of CRC in the liver.

Authors

Yoon Mee Yang, Jieun Kim, Zhijun Wang, Jina Kim, So Yeon Kim, Gyu Jeong Cho, Jee Hyung Lee, Sun Myoung Kim, Takashi Tsuchiya, Michitaka Matsuda, Vijay Pandyarajan, Stephen J. Pandol, Michael S. Lewis, Alexandra Gangi, Paul W. Noble, Dianhua Jiang, Akil Merchant, Edwin M. Posadas, Neil A. Bhowmick, Shelly C. Lu, Sungyong You, Alexander M. Xu, Ekihiro Seki

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Abstract

Tertiary lymphoid structures (TLS) in the tumor microenvironment (TME) are emerging solid-tumor indicators of prognosis and response to immunotherapy. Considering that tumorigenesis requires metabolic reprogramming and subsequent TME remodeling, the discovery of TLS metabolic regulators is expected to produce immunotherapeutic targets. To identify such metabolic regulators, we constructed a metabolism-focused sgRNA library and performed an in vivo CRISPR screening in an orthotopic lung tumor mouse model. Combined with The Cancer Genome Atlas database analysis of TLS-related metabolic hub genes, we found that the loss of Acat1 in tumor cells sensitized tumors to anti-PD1 treatment, accompanied by increased TLS in the TME. Mechanistic studies revealed that ACAT1 resulted in mitochondrial protein hypersuccinylation in lung tumor cells and subsequently enhanced mitochondrial oxidative metabolism, which impeded TLS formation. Elimination of ROS by NAC or Acat1 knockdown promoted B cell aggregation and TLS construction. Consistently, data from tissue microassays of 305 patients with lung cancer showed that TLS were more abundant in non–small cell lung cancer (NSCLC) tissues with lower ACAT1 expression. Intratumoral ACAT1 expression was associated with poor immunotherapy outcomes in patients with NSCLC. In conclusion, our results identified ACAT1 as a metabolic regulator of TLS and a promising immunotherapeutic target in NSCLC.

Authors

Mengxia Jiao, Yifan Guo, Hongyu Zhang, Haoyu Wen, Peng Chen, Zhiqiang Wang, Baichao Yu, Kameina Zhuma, Yuchen Zhang, Jingbo Qie, Yun Xing, Pengyuan Zhao, Zihe Pan, Luman Wang, Dan Zhang, Fei Li, Yijiu Ren, Chang Chen, Yiwei Chu, Jie Gu, Ronghua Liu

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Abstract

Mitochondrial dysfunction fuels vascular inflammation and atherosclerosis. Mitochondrial calcium uptake 1 (MICU1) maintains mitochondrial Ca2+ homeostasis. However, the role of MICU1 in vascular inflammation and atherosclerosis remains unknown. Here, we report that endothelial MICU1 prevents vascular inflammation and atherosclerosis by maintaining mitochondrial homeostasis. We observed that vascular inflammation was aggravated in endothelial cell–specific Micu1 knockout mice (Micu1ECKO) and attenuated in endothelial cell–specific Micu1 transgenic mice (Micu1ECTg). Furthermore, hypercholesterolemic Micu1ECKO mice also showed accelerated development of atherosclerosis, while Micu1ECTg mice were protected against atherosclerosis. Mechanistically, MICU1 depletion increased mitochondrial Ca2+ influx, thereby decreasing the expression of the mitochondrial deacetylase sirtuin 3 (SIRT3) and the ensuing deacetylation of superoxide dismutase 2 (SOD2), leading to the burst of mitochondrial reactive oxygen species (mROS). Of clinical relevance, we observed decreased MICU1 expression in the endothelial layer covering human atherosclerotic plaques and in human aortic endothelial cells exposed to serum from patients with coronary artery diseases (CAD). Two-sample Wald ratio Mendelian randomization further revealed that increased expression of MICU1 was associated with decreased risk of CAD and coronary artery bypass grafting (CABG). Our findings support MICU1 as an endogenous endothelial resilience factor that protects against vascular inflammation and atherosclerosis by maintaining mitochondrial Ca2+ homeostasis.

Authors

Lu Sun, Ruixue Leng, Monan Liu, Meiming Su, Qingze He, Zhidan Zhang, Zhenghong Liu, Zhihua Wang, Hui Jiang, Li Wang, Shuai Guo, Yiming Xu, Yuqing Huo, Clint L. Miller, Maciej Banach, Yu Huang, Paul C. Evans, Jaroslav Pelisek, Giovanni G. Camici, Bradford C. Berk, Stefan Offermanns, Junbo Ge, Suowen Xu, Jianping Weng

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Abstract

Sleep disturbance is bidirectionally associated with an increased risk of Alzheimer’s disease and other tauopathies. While the sleep-wake cycle regulates interstitial and cerebrospinal fluid (CSF) tau levels, the underlying mechanisms remain unknown. Understanding these mechanisms is crucial, given the evidence that tau pathology spreads through neuron-to-neuron transfer, involving the secretion and internalization of pathological tau forms. Here, we combined in vitro, in vivo, and clinical methods to reveal a pathway by which changes in body temperature (BT) over the sleep-wake cycle modulate extracellular tau levels. In mice, a higher BT during wakefulness and sleep deprivation increased CSF and plasma tau levels, while also upregulating unconventional protein secretion pathway I (UPS-I) events including (a) intracellular tau dephosphorylation, (b) caspase 3–mediated cleavage of tau (TauC3), and (c) membrane translocation of tau through binding to phosphatidylinositol 4,5-bisphosphate (PIP2) and syndecan 3. In humans, the increase in CSF and plasma tau levels observed after wakefulness correlated with BT increases during wakefulness. By demonstrating that sleep-wake variation in BT regulates extracellular tau levels, our findings highlight the importance of thermoregulation in linking sleep disturbances to tau-mediated neurodegeneration and the preventative potential of thermal interventions.

Authors

Geoffrey Canet, Felipe Da Gama Monteiro, Emma Rocaboy, Sofia Diego-Diaz, Boutheyna Khelaifia, Kelly Godbout, Aymane Lachhab, Jessica Kim, Daphne I. Valencia, Audrey Yin, Hau-Tieng Wu, Jordan Howell, Emily Blank, Francis Laliberté, Nadia Fortin, Emmanuelle Boscher, Parissa Fereydouni-Forouzandeh, Stéphanie Champagne, Isabelle Guisle, Sébastien S. Hébert, Vincent Pernet, Haiyan Liu, William Lu, Ludovic Debure, David M. Rapoport, Indu Ayappa, Andrew W. Varga, Ankit Parekh, Ricardo S. Osorio, Steve Lacroix, Mark P. Burns, Brendan P. Lucey, Esther M. Blessing, Emmanuel Planel

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Abstract

Polymorphisms in Nos3 increase risk for glaucoma, the leading cause of irreversible blindness worldwide. A key modifiable risk factor for glaucoma is intraocular pressure (IOP), which is regulated by NO — a product of nitric oxide synthase 3 (encoded by Nos3) — in Schlemm’s canal of the conventional outflow pathway. We studied the effects of a conditional, endothelial cell–specific postnatal deletion of Nos3 (Endo-SclCre-ERT;Nos3fl/fl) on tissues of the outflow pathway. We observed that Cre-ERT expression spontaneously and gradually increased with time in vascular endothelia including in Schlemm’s canal, beginning at P10, with complete Nos3 deletion occurring around P90. Whereas outflow resistance was reduced in global Nos3-KO mice, outflow resistance and IOP in Endo-SclCre-ERT;Nos3fl/fl mice were normal. We observed — coincident with Nos3 deletion — recruitment of macrophages to and induction of both ELAM1 and NOS2 expression by endothelia in the distal portion of the outflow pathway, which increased vessel diameter. These adjustments reduced outflow resistance to maintain IOP in these Endo-SclCre-ERT;Nos3fl/fl mice. Selective inhibition of iNOS by 1400W resulted in narrowing of distal vessels and IOP elevation. Together, the results emphasize the pliability of the outflow system and the importance of NO signaling in IOP control, and imply an substantial role for macrophages in IOP homeostasis.

Authors

Ruth A. Kelly, Megan S. Kuhn, Ester Reina-Torres, Revathi Balasubramanian, Kristin M. Perkumas, Guorong Li, Takamune Takahashi, Simon W.M. John, Michael H. Elliott, Darryl R. Overby, W. Daniel Stamer

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Abstract

Newborns exhibit a heightened vulnerability to inflammatory disorders due to their underdeveloped immune system, yet the underlying mechanisms remain poorly understood. Here we report that plasma spermidine is correlated with the maturity of human newborns and reduced risk of inflammation. Administration of spermidine led to the remission of neonatal inflammation in mice. Mechanistic studies revealed that spermidine enhanced the generation of polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) via downstream eIF5A hypusination. Genetic deficiency or pharmacological inhibition of deoxyhypusine synthase (DHPS), a key enzyme of hypusinated eIF5A (eIF5AHyp), diminished the immunosuppressive activity of PMN-MDSCs, leading to aggravated neonatal inflammation. The eIF5AHyp pathway was found to enhance the immunosuppressive function via histone acetylation–mediated epigenetic transcription of immunosuppressive signatures in PMN-MDSCs. These findings demonstrate the spermidine-eIF5AHyp metabolic axis as a master switch to restrict neonatal inflammation.

Authors

Jiale Chen, Lin Zhu, Zhaohai Cui, Yuxin Zhang, Ran Jia, Dongmei Zhou, Bo Hu, Wei Zhong, Jin Xu, Lijuan Zhang, Pan Zhou, Wenyi Mi, Haitao Wang, Zhi Yao, Ying Yu, Qiang Liu, Jie Zhou

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Abstract

Although nucleoporin 98 (NUP98) fusion oncogenes often drive aggressive pediatric leukemia by altering chromatin structure and expression of homeobox (HOX) genes, underlying mechanisms remain elusive. Here, we report that the Hoxb-associated lncRNA HoxBlinc was aberrantly activated in NUP98-PHF23 fusion–driven leukemias. HoxBlinc chromatin occupancies led to elevated mixed-lineage leukemia 1 (MLL1) recruitment and aberrant homeotic topologically associated domains (TADs) that enhanced chromatin accessibilities and activated homeotic/hematopoietic oncogenes. HoxBlinc depletion in NUP98 fusion–driven leukemia impaired HoxBlinc binding, TAD integrity, MLL1 recruitment, and the MLL1-driven chromatin signature within HoxBlinc-defined TADs in a CCCTC-binding factor–independent (CTCF-independent) manner, leading to inhibited homeotic/leukemic oncogenes that mitigated NUP98 fusion–driven leukemogenesis in xenografted mouse models. Mechanistically, HoxBlinc overexpression in the mouse hematopoietic compartment induced leukemias resembling those in NUP98-PHF23–knockin (KI) mice via enhancement of HoxBlinc chromatin binding, TAD formation, and Hox gene aberration, leading to expansion of hematopoietic stem and progenitor cell and myeloid/lymphoid cell subpopulations. Thus, our studies reveal a CTCF-independent role of HoxBlinc in leukemic TAD organization and oncogene-regulatory networks.

Authors

Karina Hamamoto, Ganqian Zhu, Qian Lai, Julia Lesperance, Huacheng Luo, Ying Li, Nupur Nigam, Arati Sharma, Feng-Chun Yang, David Claxton, Yi Qiu, Peter D. Aplan, Mingjiang Xu, Suming Huang

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Abstract

Chimeric antigen receptor (CAR) T cell therapy shows promise for various diseases. Our studies in humanized mice and nonhuman primates demonstrate that hematopoietic stem cells (HSCs) modified with anti-HIV CAR achieve lifelong engraftment, providing functional antiviral CAR-T cells that reduce viral rebound after antiretroviral therapy (ART) withdrawal. However, T cell exhaustion due to chronic immune activation remains a key obstacle to sustained CAR-T efficacy, necessitating additional measures to achieve functional cure. We recently showed that low-dose rapamycin treatment reduced inflammation and improved anti-HIV T cell function in HIV-infected humanized mice. Here, we report that rapamycin improved CAR-T cell function both in vitro and in vivo. In vitro treatment with rapamycin enhanced CAR-T cell mitochondrial respiration and cytotoxicity. In vivo treatment with low-dose rapamycin in HIV-infected, CAR-HSC mice decreased chronic inflammation, prevented exhaustion of CAR-T cells, and improved CAR-T control of viral replication. RNA-sequencing analysis of CAR-T cells from humanized mice showed that rapamycin downregulated multiple checkpoint inhibitors and upregulated key survival genes. Mice treated with CAR-HSCs and rapamycin had delayed viral rebound after ART and reduced HIV reservoir compared with those treated with CAR-HSCs alone. These findings suggest that HSC-based anti-HIV CAR-T cells combined with rapamycin treatment are a promising approach for treating persistent inflammation and improving immune control of HIV replication.

Authors

Wenli Mu, Shallu Tomer, Jeffrey Harding, Nandita Kedia, Valerie Rezek, Ethan Cook, Vaibahavi Patankar, Mayra A. Carrillo, Heather Martin, Hwee Ng, Li Wang, Matthew D. Marsden, Scott G. Kitchen, Anjie Zhen

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Abstract

Neuroretinal degenerations including retinitis pigmentosa (RP) comprise a heterogeneous collection of pathogenic mutations that ultimately result in blindness. Despite recent advances in precision medicine, therapies for rarer mutations are hindered by burdensome developmental costs. To this end, Von Hippel-Lindau (VHL) is an attractive therapeutic target to treat RP. By ablating VHL in rod photoreceptors and elevating hypoxia-inducible factor (HIF) levels, we demonstrate a path to therapeutically enhancing glycolysis independent of the underlying genetic variant that slows degeneration of both rod and cone photoreceptors in a preclinical model of retinitis pigmentosa. This rod-specific intervention also resulted in reciprocal, decreased glycolytic activity within the retinal pigment epithelium (RPE) cells despite no direct genetic modifications to the RPE. Suppressing glycolysis in the RPE provided notable, noncell-autonomous therapeutic benefits to the photoreceptors, indicative of metabolically sensitive crosstalk between different cellular compartments of the retina. Surprisingly, targeting HIF2A in RPE cells did not impact RPE glycolysis, potentially implicating HIF1A as a major regulator in mouse RPE and providing a rationale for future therapeutic efforts aimed at modulating RPE metabolism.

Authors

Salvatore Marco Caruso, Xuan Cui, Brian M. Robbings, Noah Heapes, Aykut Demikrol, Bruna Lopes Da Costa, Daniel T. Hass, Peter M.J. Quinn, Jianhai Du, James B. Hurley, Stephen H. Tsang

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Abstract

Myotonic dystrophy type 1 (DM1) is an autosomal dominant disease caused by a CTG repeat expansion in the dystrophia myotonica protein kinase (DMPK) gene. The expanded CUG repeat RNA (CUGexp RNA) transcribed from the mutant allele sequesters the muscleblind-like (MBNL) family of RNA-binding proteins, causing their loss of function and disrupting regulated pre-mRNA processing. We used a DM1 heart mouse model that inducibly expresses CUGexp RNA to test the contribution of MBNL loss to DM1 cardiac abnormalities and explored MBNL restoration as a potential therapy. AAV9-mediated overexpression of MBNL1 and/or MBNL2 significantly rescued DM1 cardiac phenotypes including conduction delays, contractile dysfunction, hypertrophy, and misregulated alternative splicing and gene expression. While robust, the rescue was partial compared with reduced CUGexp RNA and plateaued with increased exogenous MBNL expression. These findings demonstrate that MBNL loss is a major contributor to DM1 cardiac manifestations and suggest that additional mechanisms play a role, highlighting the complex nature of DM1 pathogenesis.

Authors

Rong-Chi Hu, Yi Zhang, Larissa Nitschke, Sara J. Johnson, Ayrea E. Hurley, William R. Lagor, Zheng Xia, Thomas A. Cooper

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Abstract

Metabolic reprogramming shapes the tumor microenvironment (TME) and may lead to immunotherapy resistance in pancreatic ductal adenocarcinoma (PDAC). Elucidating the impact of pancreatic cancer cell metabolism in the TME is essential to therapeutic interventions. “Immune cold” PDAC is characterized by elevated lactate levels resulting from tumor cell metabolism, abundance of protumor macrophages, and reduced cytotoxic T cells in the TME. Analysis of fluorine-18 fluorodeoxyglucose (18F-FDG) uptake in patients showed that increased global protein lactylation in PDAC correlates with worse clinical outcomes in immunotherapy. Inhibition of lactate production in pancreatic tumors via glycolysis or mutant-KRAS inhibition reshaped the TME, thereby increasing their sensitivity to immune checkpoint blockade (ICB) therapy. In pancreatic tumor cells, lactate induces K63 lactylation of endosulfine α (ENSA-K63la), a crucial step that triggers STAT3/CCL2 signaling. Consequently, elevated CCL2 secreted by tumor cells facilitates tumor-associated macrophage (TAM) recruitment to the TME. High levels of lactate also drive transcriptional reprogramming in TAMs via ENSA-STAT3 signaling, promoting an immunosuppressive environment. Targeting ENSA-K63la or CCL2 enhances the efficacy of ICB therapy in murine and humanized pancreatic tumor models. In conclusion, elevated lactylation reshapes the TME and promotes immunotherapy resistance in PDAC. A therapeutic approach targeting ENSA-K63la or CCL2 has shown promise in sensitizing pancreatic cancer immunotherapy.

Authors

Kang Sun, Xiaozhen Zhang, Jiatao Shi, Jinyan Huang, Sicheng Wang, Xiang Li, Haixiang Lin, Danyang Zhao, Mao Ye, Sirui Zhang, Li Qiu, Minqi Yang, Chuyang Liao, Lihong He, Mengyi Lao, Jinyuan Song, Na Lu, Yongtao Ji, Hanshen Yang, Lingyue Liu, Xinyuan Liu, Yan Chen, Shicheng Yao, Qianhe Xu, Jieru Lin, Yan Mao, Jingxing Zhou, Xiao Zhi, Ke Sun, Xiongbin Lu, Xueli Bai, Tingbo Liang

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Abstract

BACKGROUND Natural resistance to Mycobacterium tuberculosis (Mtb) infection in some people with HIV (PWH) is unexplained.METHODS We performed single cell RNA-sequencing of bronchoalveolar lavage cells, unstimulated or ex vivo stimulated with Mtb, for 7 PWH who were tuberculin skin test (TST) and IFN-γ release assay (IGRA) positive (called LTBI) and 6 who were persistently TST and IGRA negative (called resisters).RESULTS Alveolar macrophages (AM) from resisters displayed a baseline M1 macrophage phenotype while AM from LTBI did not. Resisters displayed alveolar lymphocytosis, with enrichment of all T cell subpopulations including IFNG-expressing cells. In both groups, mycobactericidal granulysin was expressed almost exclusively by a T cell subtype that coexpressed granzyme B, perforin and NK cell receptors. These poly-cytotoxic T lymphocytes (poly-CTL) overexpressed activating NK cell receptors and were increased in resister BAL. Following challenge with Mtb, only intraepithelial lymphocyte-like cells from LTBI participants responded with increased transcription of IFNG. AM from resisters responded with a stronger TNF signature at 6 hours after infection while at 24 hours after infection, AM from LTBI displayed a stronger IFN-γ signature. Conversely, at 24 hours after infection, only AM from resisters displayed an upregulation of MHC class I polypeptide–related sequence A (MICA) transcripts, which encode an activating ligand for poly-CTL.CONCLUSION These results suggest that poly-CTL and M1-like pre-activated AM mediate the resister phenotype in PWH.FUNDING National Institutes of Health. Canadian Institutes of Health Research. Digital Research Alliance of Canada. French National Research Agency. French National Agency for Research on AIDS and Viral Hepatitis. St. Giles Foundation. General Atlantic Foundation. South African Medical Research Council Centre for Tuberculosis Research.

Authors

Monica Dallmann-Sauer, Vinicius M. Fava, Stephanus T. Malherbe, Candice E. MacDonald, Marianna Orlova, Elouise E. Kroon, Aurélie Cobat, Stéphanie Boisson-Dupuis, Eileen G. Hoal, Laurent Abel, Marlo Möller, Jean-Laurent Casanova, Gerhard Walzl, Nelita Du Plessis, Erwin Schurr

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Abstract

Lysyl hydroxylase 2 (LH2) is highly expressed in multiple tumor types and accelerates disease progression by hydroxylating lysine residues on fibrillar collagen telopeptides to generate stable collagen cross links in tumor stroma. Here, we show that a galactosylhydroxylysyl glucosyltransferase (GGT) domain on LH2-modified type-VI collagen (Col6) to promote lung adenocarcinoma (LUAD) growth and metastasis. In tumors generated by LUAD cells lacking LH2 GGT domain activity, stroma was less stiff, and stable types of collagen cross links were reduced. Mass spectrometric analysis of total and glycosylated peptides in parental and GGT-inactive tumor samples identified Col6 chain α3 (Col6a3), a component of the Col6 heterotrimeric molecule, as a candidate LH2 substrate. In gain- and loss-of-function studies, high Col6a3 levels increased tumor growth and metastatic activity and enhanced the proliferative, migratory, and invasive activities of LUAD cells. LH2 coimmunoprecipitated with Col6a3, and LH2 glucosylated Col6 in an in vitro reaction. Glucosylation increased the integrin-binding and promigratory activities of Col6 in LUAD cells. Col6a3 K2049 was deglucosylated in GGT-inactive tumor samples, and mutagenesis of Col6a3 K2049 phenocopied Col6a3 deficiency or LH2 GGT domain inactivation in LUAD cells. Thus, LH2 glucosylates Col6 to drive LUAD progression. These findings show that the GGT domain of LH2 is protumorigenic, identify Col6 as a candidate effector, and provide a rationale to develop pharmacological strategies that target LH2’s GGT domain in cancer cells.

Authors

Shike Wang, Houfu Guo, Reo Fukushima, Masahiko Terajima, Min Liu, Guan-Yu Xiao, Lenka Koudelková, Chao Wu, Xin Liu, Jiang Yu, Emma Burris, Jun Xu, Alvise Schiavinato, William K. Russell, Mitsuo Yamauchi, Xiaochao Tan, Jonathan M. Kurie

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Abstract

The physiological impact of ultradian temporal feeding patterns remains a major unanswered question in nutritional science. We have employed automated and nasogastric feeding to address this question in male rodents and human volunteers. While grazing and meal-feeding reduced food intake in parallel (compared to ad libitum-fed rodents), body length and tibial epiphysial plate width were maintained in meal-fed rodents via the action of ghrelin and its receptor, GHS-R. Grazing and meal-feeding initially suppressed elevated pre-prandial ghrelin levels in rats, followed by either a sustained elevation in ghrelin in grazing rats or pre-prandial ghrelin surges in meal-fed rats. Episodic growth hormone (GH) secretion was largely unaffected in grazing rats, but meal-feeding tripled GH secretion, with burst height augmented and two additional bursts of GH per day. Continuous nasogastric infusion of enteral feed in humans failed to suppress circulating ghrelin, producing continuously elevated circulating GH with minimal rhythmicity. In contrast, bolus enteral infusion elicited post-prandial ghrelin troughs accompanied by reduced circulating GH, with enhanced ultradian rhythmicity. Taken together, our data imply that the contemporary shift from regular meals to snacking behaviour may be detrimental to optimal skeletal growth outcomes by sustaining circulating GH at levels associated with undernourishment and diminishing GH pulsatility.

Authors

Amanda K.E. Hornsby, Richard C. Brown, Thomas W. Tilston, Harry A. Smith, Alfonso Moreno-Cabañas, Bradley Arms-Williams, Anna L. Hopkins, Katie D. Taylor, Simran K.R. Rogaly, Lois H.M. Wells, Jamie J. Walker, Jeffrey S. Davies, Yuxiang Sun, Jeffrey M. Zigman, James A. Betts, Timothy Wells

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Abstract

The anti-metastatic activity of NK cells is well established in several cancer types, but the mechanisms underlying NK cell metastasis infiltration and acquisition of anti-tumor 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 co-localize with macrophages in CXCL9 and CXCL10 rich areas. By mining a published scRNA-seq dataset of a cohort of treatment-naïve CRC patients, 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

Aberrant O-glycosylation of the IgA1 hinge region is a characteristic finding in patients with IgA nephropathy (IgAN) and is thought to contribute to immune-complex formation and kidney injury. Other studies have suggested that abnormalities in mucosal immunity and lymphocyte homing are major contributors to disease. We identified a family with IgAN segregating a heterozygous predicted loss-of-function (LOF) variant in GALNT14, the gene encoding N-acetylgalactosaminyltransferase 14, one of the enzymes involved in mucin-type protein O-glycosylation. While GALNT14 is expressed in IgA1-producing cells, carriers of the LOF variant did not have altered levels of poorly glycosylated IgA1, suggesting other disease mechanisms. Investigation of Galnt14 null mice revealed elevated serum IgA levels and ex vivo IgA production by B cells. These mice developed glomerular IgA deposition with aging and after induction of sterile colitis. Galnt14 null mice also displayed an attenuated mucin layer in the colon and redistribution of IgA-producing cells from mucosal to systemic sites. Adoptive-transfer experiments indicated impaired homing of spleen-derived Galnt14 deficient B lymphocytes, resulting in increased retention in peripheral blood. These findings suggest that abnormalities in O-glycosylation alter mucosal immunity and B lymphocyte homing, pointing to an expanded role of aberrant O-glycosylation in the pathogenesis of IgAN.

Authors

Sindhuri Prakash, Nicholas J. Steers, Yifu Li, Elena Sanchez-Rodriguez, Miguel Verbitsky, Isabel Robbins, Jenna Simpson, Sharvari Pathak, Milan Raska, Colin Reily, Anna Ng, Judy Liang, Natalia DeMaria, Amanda Katiraei, Kelsey O'Stevens, Clara Fischman, Samantha Shapiro, Swetha Kodali, Jason McCutchan, Heekuk Park, Djamila Eliby, Marco Delsante, Landino Allegri, Enrico Fiaccadori, Monica Bodria, Maddalena Marasa, Elizabeth Raveche, Bruce A. Julian, Anne-Catrin Uhlemann, Krzysztof Kiryluk, Hong Zhang, Vivette D. D'Agati, Simone Sanna-Cherchi, Jan Novak, Ali G. Gharavi

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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 from a childhood maltreatment-exposed and non-exposed mixed population combined with human and rodent fear conditioning models. Here we show that 2-AG levels are inversely associated with fear generalization at the behavioral level in both mice and humans. In mice, 2-AG depletion increases the proportion of neurons, and the similarity between neuronal representations, of threat-predictive and neutral stimuli within prelimbic prefrontal cortex neuronal ensembles. In humans, increased dorsolateral prefrontal cortical-amygdala resting state connectivity is 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

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 (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 (Jmjd3flox/floxMyh11CreERT), we show that loss of Jmjd3 in SMCs results in HTN due to decreased EDNRB expression and increased EDNRA expression. Importantly, the Endothelin Receptor A antagonist, BQ-123, reversed HTN after Jmjd3 deletion in vivo. Additionally, single cell RNA-sequencing (scRNA-seq) of human arteries revealed 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 Barrett, Amrita Joshi, Gabriela Saldana de Jimenez, Sabrina A. Rocco, Zara Ahmed, Rachael Bogle, Kylie Boyer, Andrea Obi, Frank M Davis, Lin Chang, Lam Tsoi, Johann Gudjonsson, Scott M. Damrauer, Katherine Gallagher

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Evolving insights into MASLD and MASH pathogenesis and treatment

Series edited by Scott L. Friedman

Metabolic dysfunction associated steatotic liver disease (MASLD, formerly called NAFLD) and its more advanced form, metabolic dysfunction associated steatohepatitis (MASH, formerly called NASH) are increasing in prevalence worldwide as the number of individuals with metabolic risk factors rises. These diseases and their adverse sequelae have a formidable economic impact, and there remain large gaps in understanding and treating MASLD/MASH. Series editor Scott Friedman curated this series of expert-led review articles to cover advances and challenges across the spectrum of basic investigation to clinical trials. The reviews will address diagnostic approaches, management strategies specific to adolescent and pregnant individuals, pathobiology, and therapeutic horizons, with the goal of reflecting the heterogeneity seen in disease drivers as well as the affected population.

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