Gastroenterology
Abstract
Epigenetic modifications play a crucial role in the pathogenesis of inflammatory bowel disease (IBD) by mediating gene-environment interactions. We previously showed that UHRF1, a central regulator of DNA methylation, contributes to cancer progression; however, its function in IBD remains poorly understood. Here, we revealed that UHRF1 was frequently reduced in inflamed tissues of patients with IBD and that its deficiency exacerbated intestinal epithelial cell (IEC) damage. Through a multilevel approach incorporating human cell models and an intestinal epithelial-specific Uhrf1-KO mouse model, we established UHRF1 as a key mitigator of IBD progression. Mechanistically, UHRF1 bound to the NPY1R promoter, promoted its methylation, and led to transcriptional suppression. The NPY1R upregulation resulting from UHRF1 deficiency attenuated cAMP/PKA/CREB signaling in IECs, thereby enhancing NF-κB activation and subsequent proinflammatory responses, which compromised intestinal epithelial barrier integrity. Furthermore, we identified miR-141 as a negative regulator of NPY1R, highlighting its potential as a therapeutic agent. Collectively, our results identified the UHRF1/NPY1R regulatory axis as a critical epigenetic mechanism in intestinal inflammation and underscored its dual promise for IBD diagnostics and therapy.
Authors
Yanan Han, Lina Sun, Yanxing Liu, Xiaohui Zhang, Hao Liu, Haohao Zhang, Xiaoxia Ren, Fenfan Wang, Huafeng Fan, Jie Chen, Dan Liu, Daiming Fan, Yuanyuan Lu, Xue Bai, Ying Fang, Kaichun Wu, Xiaodi Zhao
Abstract
Adaptive immune responses are widely considered the primary drivers of chronic inflammation in autoimmune disease, yet increasing evidence suggests that dysregulated myeloid cells play a central role in sustaining tissue damage. Salt-inducible kinases (SIKs) regulate immune cell activation, and their pharmacological inhibition can promote a shift from proinflammatory toward an immunoregulatory phenotype. We investigated whether selective inhibition of SIK2 and SIK3 with GLPG3970 could reprogram monocytes, macrophages, and dendritic cells, and we assessed pharmacological effects on activated T and B cells. Preclinical studies in mouse models of colitis, psoriasis, and arthritis demonstrated that SIK2/SIK3 inhibition reduced inflammatory activity and promoted immunoregulatory and tolerogenic-associated pathways. Clinical signal-detection studies in ulcerative colitis, psoriasis, and rheumatoid arthritis revealed signs of clinical and biological activity in ulcerative colitis and psoriasis. These findings suggest that myeloid cell dysfunction and impaired myeloid phenotype switching contribute to chronic inflammation in autoimmune diseases and that therapeutic targeting of SIK2/SIK3 holds the potential to restore immune balance by converting proinflammatory into regulatory pathways. Collectively, this work supports SIK2/SIK3 inhibition as a potential treatment strategy for myeloid cell–driven chronic inflammatory conditions.
Authors
Steve De Vos, Nicolas Desroy, Susan J. Bellaire, Anna Pereira Fernandes, Stéphanie Lavazais, Didier Merciris, Carole Delachaume, Catherine Robin-Jagerschmidt, Adrien Cosson, Angela Lazaryan, Nancy Van Osselaer, David Amantini, Christophe Peixoto, Maikel L. Colli, Thomas Van Eeckhoutte, Tiina Hakonen, Magali Constant, Alberto Garcia-Hernandez, Rahul Barron, Geert D’Haens, Wulf O. Böcher
Abstract
Nearly 50% of patients with KRAS-mutant colorectal cancer (CRC) currently lack effective targeted therapy. The accumulation of KRAS-mutant proteins can trigger a sustained high level of endoplasmic reticulum (ER) stress, and the UPR-based long-term protective regulatory pathway inhibits the aggregation of unfolded proteins, thereby maintaining the stability of the ER and enabling the continued survival of KRAS-mutant tumors. However, the critical factors that affect the regulation of ER homeostasis in KRAS-mutant CRC are still unclear. Mono-ADP ribosylation (MARylation) catalyzed by ART1 is the most important modification of GRP78/BiP and stabilizes the internal environment of the ER. In this study, KRAS mutation increased the levels of ART1, ER stress, and MARylated GRP78/BiP in CRC cells. Inhibiting MARylated GRP78/BiP can impede the downstream IRE1α/XBP1/TFAF2/JNK and PERK/eIF2α/ATF4 cascades by affecting the binding and dissociation of GRP78/BiP with receptors to hinder the growth of KRAS-mutant CRC cells and accelerate their apoptosis. We propose that KRAS-mutant CRC cells are more sensitive to intervention with MARylated GRP78/BiP because more modifications are needed to maintain ER stability. We also conducted a preliminary study on the specific site of function. Clarifying this molecular mechanism can provide a experimental basis for identifying effective targets for the intervention of KRAS-mutant CRC.
Authors
Shuxian Zhang, Xiaodan Chen, Qian Gong, Jing Huang, Yi Tang, Ming Xiao, Ming Li, Qingshu Li, Yalan Wang
Abstract
Disruptions in the integrity of the intestinal epithelium occur commonly in inflammatory bowel diseases (IBD) and critical surgical disorders, but the underlying mechanisms remain largely unknown. Here we identified long noncoding RNA GAS5 as a repressor of intestinal mucosa growth and the function of the gut epithelium barrier. The levels of tissue GAS5 increased in mouse intestinal mucosa after colitis and septic stress, as well as in human intestinal mucosa from IBD patients. Transient and tissue-specific knockdown of GAS5 in mice using CRISPR-Cas9 enhanced the renewal of the mucosa of the small intestine, increased the levels of tight junction (TJ) proteins ZO-1, ZO-2, claudin-1, and claudin-2, and improved gut barrier function. Conversely, ectopic overexpression of GAS5 in intestinal organoids and in cultured intestinal epithelium cells decreased the levels of these TJ proteins and caused epithelial barrier dysfunction. Mechanistic studies revealed that GAS5 acted as a transcriptional enhancer of the gene encoding small noncoding vault RNAs (vtRNAs) and that GAS5 repressed TJ expression by increasing the levels of vtRNAs. Together, our results indicate that GAS5 disrupts the integrity of the intestinal epithelium by impairing mucosal growth and epithelial barrier function and that it represses TJ expression at least in part via vtRNAs.
Authors
Ting-Xi Yu, Hee Kyoung Chung, Amy VanderStoep, Bridgette Warner, Hongxia Chen, Haonan Zhao, Ana S. G. Cunnigham, Rosemary Kozar, Myriam Gorospe, Lan Xiao, Jian-Ying Wang
Abstract
Ulcerative colitis (UC) is a chronic inflammatory condition of the colon that primarily affects the mucosal layer. Previously, we identified autoantibodies against integrin αvβ6 in patients with UC. In this study, we established monoclonal antibodies (mAbs) from patients with UC to reveal the features and functions of these anti-integrin αvβ6 autoantibodies. We identified two shared heavy chain complementarity-determining region (CDR) 3 amino acid sequences among different patients with UC. Notably, several mAbs contained the RGD sequence in their heavy chain CDR3 that mimicked the key recognition sequence of integrin αvβ6 ligands such as fibronectin. Almost all mAbs selectively reacted with integrin αvβ6 in the presence of divalent cations (Ca²⁺ and Mg²⁺) and blocked fibronectin–integrin αvβ6 binding. MAbs that shared the same heavy chain CDR3 amino acid sequence showed differences in reactivity to integrin αvβ6, indicating that the reactivity of these mAbs is also affected by the light chain. Some of the mAbs showed varying degrees of cross-reactivity with integrin αvβ3. The identification of shared CDR3 amino acid sequences in anti-integrin αvβ6 antibodies from several patients with UC suggests a common mechanism underlying their production, which may help elucidate the pathogenesis of UC.
Authors
Masahiro Shiokawa, Yoshihiro Nishikawa, Ikuhisa Takimoto, Takeshi Kuwada, Sakiko Ota, Darryl Joy C. Juntila, Takafumi Yanaidani, Kenji Sawada, Ayako Hirata, Muneji Yasuda, Koki Chikugo, Risa Nakanishi, Masataka Yokode, Yuya Muramoto, Shimpei Matsumoto, Tomoaki Matsumori, Tsutomu Chiba, Hiroshi Seno
Abstract
Multisystemic Smooth Muscle Dysfunction Syndrome (MSMDS) is a rare disorder caused by ACTA2 mutations, including the R179H variant, which alters actin filament stability and dynamics and smooth muscle contractility. While cardiovascular complications dominate its clinical presentation, gastrointestinal (GI) dysfunction significantly impacts quality of life. To investigate the structural, functional, and cellular basis of gut dysmotility in MSMDS, we reviewed clinical data from 24 MSMDS patients and studied the ACTA2 R179H mouse model Patients exhibited severe gut dysmotility, with 75% requiring medication for chronic constipation. ACTA2 mutant mice displayed cecal and colonic dilatation, reduced intestinal length, and disrupted colonic migrating motor complexes (CMMCs). Delayed whole-gut transit and impaired contractile responses to electrical and pharmacological stimulation were observed. Transcriptomic analysis revealed significant actin cytoskeleton-related gene changes in smooth muscle cells, and immune profiling identified increased lymphocytic infiltration. Despite functional abnormalities, there were no obvious changes in the enteric nervous system. These findings establish ACTA2 mice as a robust model for studying GI pathology in MSMDS, elucidating the role of smooth muscle dysfunction in gut dysmotility. This model provides a foundation for developing targeted therapies aimed at restoring intestinal motility by directly addressing actin cytoskeletal disruptions in smooth muscle cells.
Authors
Ahmed A. Rahman, Rhian Stavely, Leah C. Ott, Christopher Y. Han, Kensuke Ohishi, Ryo Hotta, Alan J. Burns, Sabyasachi Das, Emily Da Cruz, Diana Tambala, Mark E. Lindsay, Patricia L. Musolino, Allan M. Goldstein
Abstract
The tumor microenvironment plays a key role in cancer progression and therapy resistance, with cancer-associated fibroblasts (CAFs) contributing to desmoplasia, extracellular matrix (ECM) remodeling, and elevated interstitial fluid pressure, all of which hinder drug delivery. We investigated fibroblast activation protein–targeted (FAP-targeted) near-infrared photoimmunotherapy (NIR-PIT) as a strategy to improve drug penetration in CAF-rich tumors. In clinical esophageal cancer samples, FAP expression strongly correlated with increased collagen I, hyaluronic acid, and microvascular collapse. CAF-rich 3D spheroids demonstrated elevated ECM deposition and significantly impaired drug uptake compared with CAF-poor models. FAP-targeted NIR-PIT selectively reduced CAFs, reduced ECM components, and restored drug permeability. In vivo, FAP-targeted NIR-PIT enhanced the accumulation of panitumumab and Abraxane in CAF-rich tumors and improved antitumor efficacy when combined with chemotherapy. These findings highlight FAP-targeted NIR-PIT as a promising therapeutic approach to remodel the tumor stroma and overcome drug resistance in desmoplastic solid tumors.
Authors
Seitaro Nishimura, Kazuhiro Noma, Tasuku Matsumoto, Yasushige Takeda, Tatsuya Takahashi, Hijiri Matsumoto, Kento Kawasaki, Hotaka Kawai, Tomoyoshi Kunitomo, Masaaki Akai, Teruki Kobayashi, Noriyuki Nishiwaki, Hajime Kashima, Takuya Kato, Satoru Kikuchi, Shunsuke Tanabe, Toshiaki Ohara, Hiroshi Tazawa, Yasuhiro Shirakawa, Peter L. Choyke, Hisataka Kobayashi, Toshiyoshi Fujiwara
Abstract
Induction of heme oxygenase-1 (HO-1/Hmox1) is broadly considered cytoprotective, but the role of colonic epithelial HO-1 in colitis-associated tumorigenesis is poorly defined. HO-1 catabolizes heme, releasing ferrous iron, a key driver of oxidative stress and lipid peroxidation. We observed that colonic epithelial HO-1 is induced during colitis and tumorigenesis. We also found that HO-1 is upregulated in ferroptosis-inducing conditions in murine and human colonic epithelial organoids, and correlated with lipid peroxidation and ferroptosis markers in colonic tumors. In colonic epithelial organoids exposed to heme, deletion of Hmox1 amplified a compensatory oxidative stress and detoxification transcriptional program, likely reflecting unresolved oxidative and non-oxidative toxicity from heme. In vivo, epithelial HO-1 deficient mice developed significantly fewer and smaller tumors compared to littermate controls in a colitis-associated tumorigenesis model, despite similar inflammatory injury. Tumors from knockout mice exhibited reduced iron levels, decreased lipid peroxidation, lower oxidative DNA damage, and decreased proliferation. Single-cell RNA sequencing of tumor epithelial cells revealed a shift from a proliferative to a stress-adaptive program with loss of HO-1. These findings identify epithelial HO-1 as a context-dependent regulator of tumorigenesis: protective against acute heme toxicity, but promoting iron-dependent oxidative damage and proliferation in the setting of chronic inflammation.
Authors
Rosemary C. Callahan, Jillian C. Curry, Geetha Bhagavatula, Alyse W. Staley, Rachel E.M. Schaefer, Faiz Minhajuddin, Liheng Zhou, Rane M. Neuhart, Shaikh M. Atif, David J. Orlicky, Ian M. Cartwright, Mark E. Gerich, Calen A. Steiner, Arianne L. Theiss, Caroline H.T. Hall, Sean P. Colgan, Joseph C. Onyiah
Abstract
Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis and current therapies show limited efficacy. Ligands and receptors of the TIGIT axis were analyzed using multicolor flow cytometry of tumor and blood samples, immunohistochemistry from primary tumors, and single-cell RNA sequencing from primary tumors and liver metastasis from patients with various stages of PDAC. The effect of soluble and plate-bound Nectin-4 on T cell function was tested in vitro. Further, patient-derived PDAC organoids were treated with the standard of care therapies FOLFIRINOX, gemcitabine plus paclitaxel, or the antibody-drug conjugate enfortumab vedotin. TIGIT expression was increased on tumor-infiltrating conventional and regulatory T cells compared with T cells from matched blood. Nectin-4, but not CD155 expression was associated with poor outcome. Nectin-4 was exclusively expressed by tumor cells and correlated with low immune infiltration. Notably, Nectin-4 inhibited T cell effector cytokine production in vitro. Targeting Nectin-4 with the antibody-drug conjugate enfortumab vedotin inhibited tumor growth in multiple patient-derived PDAC organoids. Collectively, our data underscores Nectin-4 as a novel therapeutic target and provides the rationale to test this agent in PDAC patients.
Authors
Max Heiduk, Carolin Beer, Sarah Cronjaeger, Emily A. Kawaler, Ulrich Sommer, Franziska Baenke, David Digomann, Loreen Natusch Bufe, Charlotte Reiche, Jessica Glück, Franziska Hoffmann, Sungsik Kim, Daniel E. Stange, Diane M. Simeone, Jürgen Weitz, Lena Seifert, Adrian M. Seifert
Abstract
Chronic liver injury results in activation of quiescent Hepatic Stellate Cells (qHSCs) into Collagen Type I-producing activated HSCs that make liver fibrotic. We identified ETS1/2 (E26 transformation-specific transcription factors 1/2) as lineage-specific transcription factors regulating HSC phenotypes. Here we investigated the role of ETS1/2 in HSCs in liver fibrosis using toxic liver injury models and 3D human liver spheroids. Liver fibrosis was induced in wild-type and HSC-specific Ets1 (Ets1ΔHSC) and Ets2 (Ets2ΔHSC) knockout mice by administration of carbon tetrachloride for 6 weeks, following cessation of liver injury for 2 weeks. Liver fibrosis was more severe in Ets1ΔHSC, and to lesser extent in Ets2ΔHSC, compared to wild-type mice. Regression of liver fibrosis was suppressed only in Ets1ΔHSC, indicating Ets1 as the predominant isoform maintaining quiescent-like phenotype in HSCs. Similar results were obtained in a MASH model using 3D human liver spheroids. Knockdown of ETS1 in human HSCs caused upregulation of fibrogenic genes in MASH human liver spheroids and prevented fibrosis regression. ETS1 regulated the qHSC phenotype via CRTC2/PGC1α/PPARγ pathway. Knockdown of CRTC2 (cAMP response element-binding protein (CREB)-regulated transcription co-activator 2) abrogated PPARγ responses and facilitated HSC activation. These findings suggest that ETS1 may represent a therapeutic target for anti-fibrotic therapy.
Authors
Wonseok Lee, Xiao Liu, Sara Brin Rosenthal, Charlene Miciano, Sadatsugu Sakane, Kanani Hokutan, Debanjan Dhar, Hyun Young Kim, David A. Brenner, Tatiana Kisseleva
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