TM9SF4 Is a Crucial Regulator of Inflammation and ER Stress in Inflammatory Bowel Disease

Mechanism underlying the role of the circRNA OMA1/miR-654-3p/RAF1 axis in children with inflammatory bowel disease

Inflammatory bowel disease (IBD), a chronic gastrointestinal disorder, often emerges during childhood and poses significant challenges due to its adverse effects on growth, development, and psychosocial well-being. Circular RNAs (circRNAs) have been implicated in the pathogenesis of diverse diseases. However, the specific biological role and mechanisms of circRNA OMA1 in children with IBD remain largely unexplored. This study investigates the functions and mechanistic pathways of circRNA OMA1 in the progression of IBD. Quantitative real-time PCR (qRT-PCR) was employed to quantify circRNA OMA1 and miR-654-3p expression levels in the serum of children with IBD and in HT-29 cells. Downstream miRNA and mRNA targets of circRNA OMA1 were predicted using StarBase and validated via luciferase reporter assays. An in vitro IBD model was established by treating the human colonic epithelial cell line (HT-29) with 2% dextran sulfate sodium (DSS). Cell viability and apoptosis were assessed using the MTT assay and flow cytometry, respectively. Expression of the apoptosis-related protein cleaved caspase-3 was analyzed via western blotting, and proinflammatory cytokine levels (TNF-α, IL-1β, and IL-6) were measured using ELISA. The expression of circRNA OMA1 was notably lower in the serum of children with IBD and in DSS-treated HT-29 cells than in healthy controls, whereas miR-654-3p expression was upregulated. Bioinformatics analyses revealed a direct interaction between circRNA OMA1 and miR-654-3p. Overexpression of circRNA OMA1 through plasmid transfection increased circRNA OMA1 levels and suppressed miR-654-3p expression in HT-29 cells under both basal and DSS-stimulated conditions. Conversely, transfection with a miR-654-3p mimic reversed these effects. Upregulation of circRNA OMA1 ameliorated DSS-induced injury in HT-29 cells by enhancing cell viability, reducing apoptosis, and downregulating cleaved caspase-3 expression. Moreover, circRNA OMA1 overexpression inhibited the secretion of inflammatory cytokines TNF-α, IL-1β, and IL-6. However, these protective effects were partially reversed by treatment with the miR-654-3p mimic. Additionally, miR-654-3p was shown to directly target RAF1, negatively regulating its expression. The proliferation-promoting and apoptosis-suppressing effects of miR-654-3p inhibitor treatment were mitigated by RAF1-siRNA. Conclusion: Upregulation of circRNA OMA1 alleviates DSS-induced colonic cell apoptosis and inflammation by modulating the miR-654-3p/RAF1 axis. These findings suggest that circRNA OMA1 could be a promising biomarker for the diagnosis and treatment of IBD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10616-025-00703-z.

Selenium maintains intestinal epithelial cells to activate M2 macrophages against deoxynivalenol injury

Selenium (Se) is indispensable in alleviating various types of intestinal injuries. Here, we thoroughly investigated the protective effect of Se on the regulation of the epithelial cell-M2 macrophages pathway in deoxynivalenol (DON)-induced intestinal damage. In the present study, Se has positive impacts on gut health by improving gut barrier function and reducing the levels of serum DON in vivo. Furthermore, our study revealed that Se supplementation increased the abundances of GPX4, p-PI3K, and AKT, decreased the levels of 4-HNE and inhibited ferroptosis. Moreover, when mice were treated with DON and Fer-1(ferroptosis inhibitor), ferroptosis was suppressed and PI3K/AKT pathway was activated. These results indicated that GPX4-PI3K/AKT-ferroptosis was a predominant pathway in DON-induced intestinal inflammation. Interestingly, we discovered that both the number of M2 anti-inflammatory macrophages and the levels of CSF-1 decreased while the pro-inflammatory cytokine IL-6 increased in the intestine and MODE-K cells supernatant. Therefore, Se supplementation activated the CSF-1-M2 macrophages axis, resulting in a decrease in IL-6 expression and an enhancement of the intestinal anti-inflammatory capacity. This study provides novel insights into how intestinal epithelial cells regulate the CSF-1-M2 macrophage pathway, which is essential in maintaining intestinal homeostasis confer to environmental hazardous stimuli.

Comparative analysis of the expression patterns of TM9SF family members in mice

Transmembrane 9 superfamily proteins (TM9SFs) define a highly conserved protein family, each member of which is characterized by a variable extracellular domain and presumably nine transmembrane domains. Although previous studies have delineated the potential cytological roles of TM9SFs like autophagy and secretory pathway, their functions during development are largely unknown. To establish the basis for dissecting the functions of TM9SFs in vivo, we employed the open-source database, structure prediction, immunofluorescence and Western blot to describe the gene and protein expression patterns of TM9SFs in human and mouse. While TM9SFs are ubiquitously and homogeneously expressed in all tissues in human with RNA sequencing and proteomics analysis, we found that all mice Tm9sf proteins are preferentially expressed in lung except Tm9sf1 which is enriched in brain although they all distributed in various tissues we examined. In addition, we further explored their expression patterns in the mice central nervous system (CNS) and its extension tissue retina. Interestingly, we could show that Tm9sf1is developmentally up-regulated in brain. In addition, we also detected all Tm9sf proteins are located in neurons and microglia instead of astrocytes. Importantly, Tm9sf3 is localized in the nuclei which is distinct from the other members that are dominantly targeted to the plasma membrane/cytoplasm as expected. Finally, we also found that Tm9sf family members are broadly expressed in the layers of INL, OPL, and GCL of retina and likely targeted to the plasma membrane of retinal cells. Thus, our data provided a comprehensive overview of TM9SFs expression patterns, illustrating their ubiquitous roles in different organs, implying the possible roles of Tm9sf2/3/4 in lung functions and Tm9sf1 in neurodevelopment, and highlighting a unique cell biological functions of TM9SF3 in neuronal and microglia.

Endoplasmic reticulum stress: A possible connection between intestinal inflammation and neurodegenerative disorders

BACKGROUND

Different studies have shown the key role of endoplasmic reticulum (ER) stress in autoimmune and chronic inflammatory disorders, as well as in neurodegenerative diseases. ER stress leads to the formation of misfolded proteins which affect the secretion of different cell types that are crucial for the intestinal homeostasis.

PURPOSE

In this review, we discuss the role of ER stress and its involvement in the development of inflammatory bowel diseases, chronic conditions that can cause severe damage of the gastrointestinal tract, focusing on the alteration of Paneth cells and goblet cells (the principal secretory phenotypes of the intestinal epithelial cells). ER stress is also discussed in the context of neurodegenerative diseases, in which protein misfolding represents the signature mechanism. ER stress in the bowel and consequent accumulation of misfolded proteins might represent a bridge between bowel inflammation and neurodegeneration along the gut-to-brain axis, affecting intestinal epithelial homeostasis and the equilibrium of the commensal microbiota. Targeting intestinal ER stress could foster future studies for designing new biomarkers and new therapeutic approaches for neurodegenerative disorders.

Gα12 and endoplasmic reticulum stress-mediated pyroptosis in a single cycle of dextran sulfate-induced mouse colitis

Inflammatory bowel disease (IBD) pathogenesis involves complex inflammatory events and cell death. Although IBD involves mainly necrosis in the digestive tract, pyroptosis has also been recognized. Nonetheless, the underlying basis is elusive. Gα12/13 overexpression may affect endoplasmic reticulum (ER) stress. This study examined how Gα12/13 and ER stress affect pyroptosis using dextran sulfate sodium (DSS)-induced colitis models. Gα12/13 levels were increased in the distal and proximal colons of mice exposed to a single cycle of DSS, as accompanied by increases of IRE1α, ATF6, and p-PERK. Moreover, Il-6, Il-1β, Ym1, and Arg1 mRNA levels were increased with caspase-1 and IL-1β activation, supportive of pyroptosis. In the distal colon, RIPK1/3 levels were enhanced to a greater degree, confirming necroptosis. By contrast, the mice subjected to three cycles of DSS treatments showed decreases of Gα12/13, as accompanied by IRE1α and ATF6 suppression, but increases of RIPK1/3 and c-Cas3. AZ2 treatment, which inhibited Gα12, has an anti-pyroptotic effect against a single cycle of colitis. These results show that a single cycle of DSS-induced colitis may cause ER stress-induced pyroptosis as mediated by Gα12 overexpression in addition to necroptosis, but three cycles model induces only necroptosis, and that AZ2 may have an anti-pyroptotic effect.

Endoplasmic reticulum stress related genome-wide Mendelian randomization identifies therapeutic genes for ulcerative colitis and Crohn's disease

Background: Endoplasmic reticulum stress (ERS) is an important pathophysiological mechanism in ulcerative colitis (UC) and Crohn's disease (CD). ERS-related genes may be influenced by genetic factors and intestinal inflammation. However, the role of ERS as a trigger or potential etiological factor for UC and CD is unclear, as the expression of ERS-related genes in UC and CD may be the cause or subsequent changes in intestinal inflammation. Here, we used a three-step summary data-based Mendelian randomization (SMR) approach integrating multi-omics data to identify putative causal effects of ERS-related genes in UC and CD. Methods: Genome-wide association study (GWAS) summary data for UC (6,968 cases and 20,464 controls) and CD (5,956 cases and 14,927 controls) were extracted as outcome, and DNA methylation quantitative trait loci (mQTL, 1,980 participants) data and expression QTL data (eQTL, 31,684 participants) from the blood were obtained as exposure. The ERS-related genes were extracted from the GeneCards database, and then the GWAS summary data were integrated with the mQTL and eQTL data associated with ERS genes by SMR. Sensitivity analysis included two-sample MR analysis, power calculations, Bayesian co-localization analysis, and phenotype scanning were performed to evaluate the robustness of the results. Results: A total of 1,193 ERS-related genes were obtained. The three-step SMR analysis showed that cg24011261 CpG site regulating GPX1 expression was associated with a low risk of UC, whereas GPX1 expression regulated by a combination of cg05055782, cg24011261, and cg05551922 CpG sites was associated with a low risk of CD. Sensitivity analysis further supports these findings. Conclusion: This multi-omics integration study identifies a causal relationship between the role of ERS in UC and CD and suggests potential new therapeutic targets for clinical practice.

Morphological analysis of cell cannibalism: An auxiliary tool in the prediction of central giant cell granuloma clinical behavior

Central giant cell granuloma (CGCG) is a benign jaw lesion with variable clinical behavior. Cell cannibalism is a cellular process associated with aggressiveness and invasion in malignant neoplasms. Here, we morphologically investigated cell cannibalism as an auxiliary method to predict CGCG clinical behavior. Cell cannibalism was quantitatively evaluated in 19 cases of peripheral giant cell granuloma (PGCG), 38 cases of CGCG (non-aggressive and aggressive), and 19 cases of giant cell tumor of bone (GCT) stained with hematoxylin and eosin. T-test was performed to assess the differences between the variables analyzed (p ≤ 0.05). Cell cannibalism was identified in 21% of non-aggressive CGCGs and 68.4% of aggressive CGCGs. A significantly higher amount of cannibal multinucleated giant cells (CMGC) was observed in aggressive CGCG compared to PGCG and non-aggressive CGCG (p = 0.042; p = 0.044, respectively). There were no significant differences in the CMGC index between non-aggressive CGCG and PGCG (p = 0.858) and between aggressive CGCG and GCT (p = 0.069). CGGC cases that exhibited rapid growth and tooth displacement and/or root resorption had a higher amount of CMGC (p = 0.035; p = 0.041, respectively). Cell cannibalism can be identified in CGCG through routine anatomopathological examination. The quantification of CMGC can help to predict the clinical behavior of central giant cell granuloma.

Comprehensive analysis of endoplasmic reticulum stress-associated genes signature of ulcerative colitis

Background

Endoplasmic reticulum stress (ERS) is a critical factor in the development of ulcerative colitis (UC); however, the underlying molecular mechanisms remain unclear. This study aims to identify pivotal molecular mechanisms related to ERS in UC pathogenesis and provide novel therapeutic targets for UC.

Methods

Colon tissue gene expression profiles and clinical information of UC patients and healthy controls were obtained from the Gene Expression Omnibus (GEO) database, and the ERS-related gene set was downloaded from GeneCards for analysis. Weighted gene co-expression network analysis (WGCNA) and differential expression analysis were utilized to identify pivotal modules and genes associated with UC. A consensus clustering algorithm was used to classify UC patients. The CIBERSORT algorithm was employed to evaluate the immune cell infiltration. Gene Set Variation Analysis (GSVA), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to explore potential biological mechanisms. The external sets were used to validate and identify the relationship of ERS-related genes with biologics. Small molecule compounds were predicted using the Connectivity Map (CMap) database. Molecular docking was performed to simulate the binding conformation of small molecule compounds and key targets.

Results

The study identified 915 differentially expressed genes (DEGs) and 11 ERS-related genes (ERSRGs) from the colonic mucosa of UC patients and healthy controls, and these genes had good diagnostic value and were highly correlated. Five potential small-molecule drugs sharing tubulin inhibitors were identified, including albendazole, fenbendazole, flubendazole, griseofulvin, and noscapine, among which noscapine exhibited the highest correlation with a high binding affinity to the targets. Active UC and 10 ERSRGs were associated with a large number of immune cells, and ERS was also associated with colon mucosal invasion of active UC. Significant differences in gene expression patterns and immune cell infiltration abundance were observed among ERS-related subtypes.

Conclusion

The results suggest that ERS plays a vital role in UC pathogenesis, and noscapine may be a promising therapeutic agent for UC by affecting ERS.

ER stress modulates the immune regulatory ability in gut M2 cells of patients with ulcerative colitis

This study aims to characterize the impaired immune regulatory function of Mφ obtained from UC patient colon lavage fluid (CLF). Mφs were the largest proportion (21.3 4.0%) of the CLF-derived cellular components. Less abundant and weaker immune suppressive function were observed in M2 Mφs (M2 cells) of the ulcerative colitis (UC) group. High levels of endoplasmic reticulum (ER) stress associated molecules were detected in UC M2 cells. The spliced X box binding protein-1 (XBP1) gene was negatively correlated with programmed death ligand-1 (PD-L1) in UC M2 cells. XBP1 promoted the expression of ring-finger protein 20 (Rnf20) in M2 cells. Rnf20 reduced PD-L1 abundance in UC M2 cells and impaired the immune suppressive ability. Inhibition of Rnf20 restored the immune regulating capacity of M2 cells and suppressed experimental colitis.

The role of endoplasmic reticulum stress in regulation of intestinal barrier and inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory disease involving the digestive tract, characterized by abdominal pain, diarrhea, rectal bleeding, and so on, which can make patients physically weakened and live difficultly. Although IBD has been recognized for many years, the pathogenesis of IBD has not yet been established and damage to intestinal barrier is thought to be closely associated with IBD. Intestinal barrier is an innate barrier that maintains the homeostasis of the intestinal environment and impedes pathogenic bacteria and toxins, and the endoplasmic reticulum (ER) has recently been found to be involved in maintaining the integrity of intestinal barrier. Endoplasmic reticulum stress (ERS) is a status of endoplasmic reticulum damaged when unfolded or misfolded proteins accumulate in excess of the degradation systematic clearance limit of the misfolded proteins. The regulation of ERS on protein folding synthesis and maintenance of cellular homeostasis is an important factor in influencing the integrity of the intestinal barrier. This paper mainly discusses the relationship between ERS and the intestinal barrier, aiming to understand the regulatory role of ERS on the intestinal barrier and the mechanism and to improve new solutions and notions for the treatment or prevention of IBD.

Transient receptor potential vanilloid type 4 (TRPV4) promotes tumorigenesis via NFAT4 activation in nasopharyngeal carcinoma

Transient receptor potential vanilloid type 4 (TRPV4) can function as an oncogene or tumor suppressor depending on the tumor types. However, little is known regarding the effect of TRPV4 in nasopharyngeal carcinoma (NPC), a highly prevalent malignancy in Southern China and Southeast Asia. We found that TRPV4 mRNA and protein levels were significantly upregulated in NPC tissues. In addition, activation of TRPV4 in NPC cell lines using GSK1016790A (100 nM) induced a Ca²⁺ influx, whereas pharmacological inhibition or gene knockdown of TRPV4 reduced the proliferation rates of NPC cells. TRPV4 knockdown also decreased the growth of tumor xenografts in vivo. Mechanistically, TRPV4-mediated tumorigenesis is dependent on the activation of Ca²⁺/calcineurin/calcineurin-nuclear factor of activated T cell 4 (NFAT4) signaling. Furthermore, NFAT4 protein level was overexpressed in NPC tissues and correlated positively with TRPV4. Taken together, TRPV4 promotes the malignant potential of NPC cells by activating NFAT4 signaling. Our findings highlight TRPV4-NFAT4 axis as a potential therapeutic target in NPC.

Piperine alleviates acute pancreatitis: A possible role for FAM134B and CCPG1 dependent ER-phagy

BACKGROUND

Acute pancreatitis was a common acute abdominal disease characterized by pancreatic acinar cell death and inflammation. Endoplasmic reticulum autophagy (ER-phagy) coud maintain cell homeostasis by degrading redundant and disordered endoplasmic reticulum and FAM134B and CCPG1 was main ER-phagy receptors. As a natural alkaloid, piperin is found in black pepper and has anti-inflammatory properties, whose effect on ER-phagy in pancreatitis has not been studied.

PURPOSE

The objective of this study was to demonstrate the pivotal role of FAM134B and CCPG1 dependent ER-phagy for alleviating acute pancreatitis and explore the molecular mechanism of piperine in alleviating acute pancreatitis.

METHOD

In this study we investigated the role of ER-phagy in acute pancreatitis and whether piperine could alleviate pancreatitis through ER-phagy regulation. We first detected endoplasmic reticulum stress (ER-stress) and ER-phagy in different degrees of acute pancreatitis. Then we used ER-stress and autophagy regulators to explore the relationship between ER-stress and ER-phagy in acute pancreatitis and their regulation of cell death. Through using FAM134B^-/- and CCPG1^-/-, we investigated the mechanism of piperine in the treatment of acute pancreatitis.

RESULTS

In this study, we confirmed that with the progression of acute pancreatitis, the pancreatic endoplasmic reticulum stress increased continuously, but the ER-phagy increased first and then was inhibited. Meanwhile, in acute pancreatitis, ER-stress and ER-phagy interacted: endoplasmic reticulum stress can induce ER-phagy, but serious ER-stress would inhibit ER-phagy; and ER-phagy could alleviate ER-stress. Next, we found that piperine reduced ER-stress by enhancing FAM134B and CCPG1 dependent ER-phagy, thereby alleviating pancreatic injury.

CONCLUSION

Impaired ER-phagy was both a cause and a consequence of ER-stress in AP mice, which contributed to the transition from AP to SAP. Piperine targeting ER-phagy provided a new insight into the pharmacological mechanism of piperine in treating AP.