Gastroenterology
Abstract
Western diets (WD), high in saturated fats such as palmitic acid (PA), promote enteric neurodegeneration and motility disorders. Using murine models, in vitro systems, and human myenteric ganglia, we investigated whether WD and PA drive iron-dependent ferroptotic injury in the enteric nervous system. Mice were fed control diet (CD) or WD for 12 weeks, with or without systemic AAV9-MaCPNS2 delivery of Nfe2l2 to enteric neurons. Colonic motility was assessed by bead-expulsion assay. Ferroptosis was assessed using convergent readouts including iron dysregulation (TfR1, FTH-1, labile and mitochondrial Fe2+), lipid peroxidation (C11-BODIPY and 4-HNE), GPX4 suppression, and pharmacologic inhibition by ferrostatin-1 (Fer-1) in primary enteric neurons, murine myenteric plexuses, and human networks of myenteric ganglia (nhMPG). WD-fed mice exhibited delayed colonic transit, increased TfR1 and FTH-1, and vulnerability of nNOS neurons; these changes were reversed by Nfe2l2 overexpression. RNA-seq of PA-treated IM-FEN neuronal cells revealed disrupted of neurotransmitter signaling, reduced mitochondrial and antioxidant programs, and increased iron import and lipid peroxidation signatures. PA increased labile iron, mitochondrial ROS, membrane depolarization, Ca2+ dysregulation, 4-HNE, and Mfrn2, while Fer-1 preserved mitochondrial integrity, viability, and ENS function. In human nhMPG, PA induced enteric neuronal iron loading and ferroptosis, supporting translational relevance to diet-associated enteric neuropathy.
Authors
Arun Balasubramaniam, Dmitrii Pavlov, Yunpeng Du, Jeremy Reeves, Alan Harzman, Yunshan Liu, Francesca Cingolani, Xinxu Yuan, Jay M. Patel, Simon Musyoka Mwangi, Peijian He, C. Michael Hart, Wenhui Hu, Fievos L. Christofi, Shanthi Srinivasan
Abstract
Cytokines mediating epithelial and immune cell interactions modulate mucosal healing—a process that goes awry with chronic inflammation as in inflammatory bowel disease. TNFSF13 is a cytokine important for B cell maturation and function, but roles for epithelial TNFSF13 and putative contribution to inflammatory bowel disease are poorly understood. We evaluated functional consequences of a novel monoallelic TNFSF13 variant using biopsies, tissue-derived colonoids and induced pluripotent stem cell (iPSC)-derived colon organoids. TNFSF13 variant colonoids exhibited a >50% reduction in secreted TNFSF13, increased epithelial proliferation, and reduced apoptosis, which was confirmed in iPSC-derived colon organoids. Single cell RNA-sequencing and flow cytometry suggested FAS as the predominant colonic epithelial receptor for TNFSF13, which was confirmed by co-immunoprecipitation and binding assays. Imaging mass cytometry revealed an increase in epithelial-associated B cells in TNFSF13 variant colon tissue sections. Finally, TNFSF13 variant colonoids co-cultured with memory B cells demonstrated a reduction in immunoglobulin-producing plasma cells compared to control colonoid cocultures. Our findings support a role for epithelial TNFSF13 as a regulator of colonic epithelial growth and epithelial crosstalk with B cells.
Authors
Xianghui Ma, Shaneice K. Nettleford, Yuhua Tian, Noor Dawany, Ayano Kondo, Yalan Li, Kelly Maurer, Tatiana A. Karakasheva, Rawan Shraim, Patrick A. Williams, Louis R. Parham, Lauren A. Simon, Charles H. Danan, Maire A. Conrad, David A. Piccoli, Marcella Devoto, Neil Romberg, Kathleen E. Sullivan, Klaus H. Kaestner, Judith R. Kelsen, Kathryn E. Hamilton
Abstract
Cellular and molecular heterogeneity in the liver has been increasingly recognized to drive liver fibrosis progression, but the particular events that occur initially in response to liver injury and trigger the immune cell recruitment remain unclear. Here, we identify epigenetically aberrant liver sinusoidal endothelial cells (LSECs) as key players in this process. Mechanistically, the epigenetic readers like bromodomain-containing protein 4 (BRD4)-dependent super-enhancers (SEs) activate proinflammatory genes, including promyelocytic leukemia (PML). PML in turn binds BRD4 and amplifies proinflammatory angiocrine signaling through phase separation-dependent SE-activation via PML/BRD4 condensate formation. In mouse models, LSEC-specific depletion of the PML/BRD4 complex mitigates liver inflammation and fibrosis. Single-cell RNA-sequencing reveals that epigenetically aberrant LSECs exhibit a reprogrammed proinflammatory angiocrine landscape in mouse fibrotic livers. TIMP1+ LSECs promote the recruitment of CD63+ monocyte-derived macrophages (MoMFs) during liver fibrosis progression. Thereby, PML/BRD4 in LSECs governs inflammatory immune cell recruitment in liver fibrosis. Pharmacological BRD4 inhibition or epigenetic PML-SE repression alleviates liver inflammation and fibrosis. In conclusion, PML/BRD4-mediated SE activation via phase separation drives proinflammatory angiocrine signaling in LSECs, initiating the inflammatory cascade and subsequent immune cell recruitment during liver fibrosis.
Authors
Can Gan, Enjiang Lai, Yang Tai, Shuai Chen, Chong Zhao, Wenting Dai, Zhu Yang, Bei Li, Tian Lan, Yang Xiao, Yangkun Guo, Jiaxin Chen, Bo Wei, Zhaodi Che, Sheng Cao, Mengfei Liu, Frank Tacke, Chengwei Tang, Vijay H. Shah, Haopeng Yu, Fei Wang, Zhiyin Huang, Jinhang Gao
Abstract
The dynamic assembly and regulation of the IκB kinase (IKK) complex in the NF-κB pathway are central to the pathogenesis and progression of inflammatory bowel disease (IBD). We recently reported that the transcription factor hematopoietically-expressed homeobox (HHEX) promotes colitis-associated colorectal cancer, but the potential role of HHEX in intestinal inflammation remains uncharacterized. Here, we found that HHEX is upregulated in inflamed colons in a colitis mouse model and in clinical IBD samples. HHEX overexpression increased inflammatory cytokine expression, and HHEX loss largely abrogated the inflammatory response in vitro and intestinal inflammation in vivo. Mechanistically, IKKα phosphorylates HHEX at S213 to stabilize HHEX in response to TNF-α by inhibiting the interaction of HHEX with the E3 ubiquitin ligase MID2 and subsequent K48-linked ubiquitination and protein degradation. Importantly, HHEX interacts with and stabilizes the IKKα/IKKβ complex via its N-terminal domain, thereby activating the NF-κB pathway and establishing a positive feedback loop that exacerbates intestinal inflammation. Our study reveals a transcription-independent function of HHEX in promoting IKK complex assembly and colitis, identifying HHEX as an IBD susceptibility gene and a potential target for IBD treatment.
Authors
Zhebin Hua, Weimin Xu, Wenjun Ding, Zhuoyue Fu, Yaosheng Wang, Yiqing Yang, Fangyuan Liu, Zhujiang Dai, Wenbo Tang, Weijun Ou, Wensong Ge, YingWei Chen, Zhongchuan Wang, Chen-Ying Liu, Peng Du
Abstract
Enteric nervous system (ENS) injury, characterized by progressive degeneration of enteric neurons and glial cells, is a common diabetic complication with no effective cure beyond symptomatic management. Enteric neural precursor cells (ENPCs) play a key role in maintaining neurogenesis and gliogenesis within the adult ENS. Here, we demonstrate that bone marrow mesenchymal stem cell–derived microvesicles (BMSC-MVs) alleviate diabetic ENS injury. In both diabetic patients and mouse models, gastrointestinal transit was delayed, ENS structure was impaired, and neurogenesis and gliogenesis from ENPCs were elevated yet remained functionally insufficient. Transcriptomic profiling revealed activation of ER stress and the pro-apoptotic PERK branch of the unfolded protein response in ENPCs. BMSC-MVs homed to the colon, were internalized by ENPCs, and suppressed ER stress, thereby enhancing functional neurogenesis and gliogenesis, restoring ENS structure, and improving gastrointestinal motility. Mechanistically, vinculin on BMSC-MVs bound talin-1 on ENPCs, activating the ERK pathway to suppress diabetic ER stress. These results identify BMSC-MVs as a promising cell-free therapeutic strategy for diabetic ENS injury.
Authors
Huiying Shi, Hailing Yao, Yilin Liu, Mengke Fan, Sicheng Cai, Shizhao Xu, Chen Jiang, Yurui Zhang, Weiwei Jiang, Wei Qian, Rong Lin
Abstract
Acquired generalized lipodystrophy (AGL) is a rare metabolic disorder frequently associated with autoimmunity. Its etiology is incompletely understood, and the effect of adipose tissue loss on intestinal inflammation in AGL remains unclear. Using mass cytometry and single-cell RNA-seq, we observed an oligoclonal expansion of T cells in the periphery and inflamed intestine in a patient with AGL and Crohn’s disease (AGLCD). To explore if loss of adipose tissue triggers lymphoproliferation, we studied lipodystrophic mice as a model for AGL. Unexpectedly, lipodystrophic mice did not show T cell expansion, were protected from colitis, and displayed a defect in the development of proinflammatory T cells, which could be reversed by allogeneic fat transplantations, indicating that clonal T cell expansion in AGLCD is not primarily caused by lipodystrophy. Instead, gene sequencing revealed a T cell–intrinsic de novo neuroblastoma RAS viral oncogene homolog (NRAS) mutation, implicating somatic mosaicism as a facilitator of clonal T cell expansion and intestinal inflammation in AGLCD.
Authors
Marilena Letizia, Toka Omar, Patrick Weidner, Manuel O. Jakob, Inka Freise, Susanne M. Krug, Britt-Sabina Löscher, Elisa Rosati, Benedikt Obermayer, Reyes Gamez-Belmonte, Julia Hecker, Jörn-Felix Ziegler, Benjamin Weixler, Patrick Asbach, Desiree Kunkel, Michael Stumvoll, Konstanze Miehle, Christoph Becker, Christoph S.N. Klose, Rainer Glauben, Dieter Beule, Anja A. Kühl, Thomas Conrad, Frank Tacke, Stefan Wirtz, Andre Franke, Ashley D. Sanders, Britta Siegmund, Carl Weidinger
Abstract
Immune evasion is a major obstacle ahead of pancreatic cancer therapy. Recent data implicate pro-inflammatory macrophages in the progression of pancreatic ductal adenocarcinoma (PDAC) and its therapeutic response. However, whether or which of the pro-inflammatory macrophage subtypes play a crucial role in the immune escape of PDAC remains unclear. Here we identify a population of CD138+ tumor-associated macrophages (TAMs), characterized by their pro-inflammatory and neutrophil-chemotactic activity, which undergo significant expansion in both PDAC patients and mouse models. These cells are elicited by a local synergy between IL-34-syndecan-1 and PGE2-EP2 signaling and are associated with immune evasion and poor clinical outcomes in patients, while also promoting immune escape and disease progression in mouse models. Mechanistically, CD138+ TAMs establish a feedforward loop with immunosuppressive Siglec-F+ neutrophils, which exhibit elevated PGE2 expression, via the secretion of Saa3 and Cxcl1. Targeting CD138+ TAMs by disrupting IL-34-syndecan-1 signaling with anti-IL-34 neutralizing antibodies significantly suppresses PDAC progression, especially when combined with anti-PD-1 antibodies. Together, our study elucidates a CD138+ TAM-Siglec-F+ neutrophil axis that drives immune escape in PDAC and proposes a therapeutic strategy that integrates IL-34-syndecan-1 signaling blockade with anti-PD-1 immunotherapy for the treatment of PDAC.
Authors
Chao Wang, Qi Zhang, Jinyan Huang, Fangyu Lin, Danyang Zhao, Youling Mu, Junshuo Tong, Jinping Li, Yingjiqiong Liang, Tao Zeng, Fukang Shi, Hang Shen, Tingting Lu, Tingbo Liang
Abstract
Isolating commensal fungi from mouse intestines has been challenging, limiting our understanding of their role in intestinal immune homeostasis and diseases. Using an Fc fusion protein of the C-type lectin Dectin-2, we successfully purified the commensal Ascomycota fungus Engyodontium sp. from mouse feces. Engyodontium enhances the antimicrobial activity of colonic neutrophils via CARD9 pathway, and exacerbates colitis by impairing the colonization of intestinal Lactobacillus johnsonii (L. johnsonii) WXY strain. L. johnsonii produces high levels of L-glutamic acid by expressing the glutaminase-encoding gene glsA to facilitate Treg expansion via enhancing IL-2 receptor signaling. Patients with Crohn’s disease (CD) and ulcerative colitis harbored increased Engyodontium and decreased L. johnsonii abundance. Engyodontium directly induced calprotectin in human colonic neutrophils, and CD patients exhibited lower levels of L-glutamic acid which also promoted human Treg expansion. These findings highlight the Engyodontium-calprotectin axis against the Lactobacillus-glutamate-Treg cascade to aggravate colitis, suggesting commensal Engyodontium-triggered signaling as a therapeutic target for mucosal inflammatory diseases.
Authors
Xinying Wang, Haiyang Sun, Ying Tan, Shaoting Xu, Zishan Liu, Kaile Ji, Ding Qiu, Jianping Deng, Bingbing Feng, Xueting Wu, Yoichiro Iwakura, Minhu Chen, Rui Feng, Chanyan Huang, Ce Tang
Abstract
The gastrointestinal tract varies in structure and function by region, yet the drivers of region-specific inflammatory disease remain elusive. Here, a TNF-overexpressing murine model (TnfΔARE/+) of Crohn’s disease (CD) was used to investigate how pathobionts interact with host immune susceptibilities to drive region-specific disease. We identified the pathobiont Chlamydia muridarum, an intracellular bacterium and murine counterpart to the human sexually transmitted C. trachomatis, as a necessary and sufficient trigger for disease manifestation in the proximal/ascending colon, a common site of CD. In genetically susceptible hosts, pathobiont-triggered proximal colonic inflammation is driven by goblet cell responses, one of which through tryptophan metabolism via indoleamine 2,3-dioxygenase (IDO1). Our findings translate to human disease, where we demonstrate upregulation of epithelia-derived IDO1 in actively inflamed ascending colon specimens, but not actively inflamed terminal ileum specimens, of CD patients. Our findings mechanistically reveal how genetic and microbial factors drive the manifestation of disease in a region-specific manner and provide a unique model to study CD specific to the ascending colon.
Authors
Paige N. Spencer, Monica E. Brown, Erin P. Smith, Jiawei Wang, William Kim, Luisella Spiga, Naila Tasneem, Alan J. Simmons, Taewoo Kim, Yilin Yang, Yanwen Xu, Lin Zheng, James Ro, Harsimran Kaur, Seung Woo Kang, Matthew D. Helou, Mason A. Lee, Deronisha Arceneaux, Katherine D. Mueller, Ozge S. Kuddar, Mariah H. Harned, Jing Li, Amrita Banerjee, Nicholas O. Markham, Keith T. Wilson, Lori A. Coburn, Jeremy A. Goettel, Qi Liu, M. Kay Washington, Raphael H. Valdivia, Wenhan Zhu, Ken S. Lau
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most widely used medications for the management of chronic pain; however, they are associated with numerous gastrointestinal (GI) adverse events. Although many mechanisms have been suggested, NSAID-induced enteropathy has been thought to be primarily due to inhibition of both cyclooxygenases (COX) -1 and -2, which results in suppression of prostaglandin synthesis. Yet surprisingly, we found that concomitant postnatal deletion of Cox-1 and -2 over 10 months failed to cause intestinal injury in mice unless they were treated with naproxen or its structural analog, phenylpropionic acid, which is not a COX inhibitor. Cox double knockout mice exhibit a distinct gut microbiome composition and cohousing them with controls rescues their dysbiosis and delays the onset of NSAID-induced GI bleeding. In both the UK Biobank and All of Us human cohorts, coadministration of antibiotics with NSAIDs is associated with an increased frequency of GI bleeding. These results show that prostaglandin suppression plays a trivial role in NSAID-induced enteropathy. However, Cox deletion causes dysbiosis of the gut microbiome that amplifies the enteropathic response to NSAIDs.
Authors
Kayla Barekat, Soumita Ghosh, Christin Herrmann, Karl Keat, Charles-Antoine Assenmacher, Ceylan Tanes, Naomi Wilson, Ronan Lordan, Antonijo Mrčela, Lubica Rauova, Arjun Sengupta, Ujjalkumar Subhash Das, Robin Joshi, Elliot Friedman, Marylyn D. Ritchie, Kyle Bittinger, Aalim Weljie, Ken Cadwell, Frederic D. Bushman, Gary D. Wu, Garret A. FitzGerald, Emanuela Ricciotti
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)