scholarly journals Endoplasmic Reticulum Stress in Subepithelial Myofibroblasts Increases the TGF-β1 Activity That Regulates Fibrosis in Crohn’s Disease

2020 ◽  
Vol 26 (6) ◽  
pp. 809-819 ◽  
Author(s):  
Chao Li ◽  
John R Grider ◽  
Karnam S Murthy ◽  
Jaime Bohl ◽  
Emily Rivet ◽  
...  

Abstract Background Endoplasmic reticulum (ER) stress is an essential response of epithelial and immune cells to inflammation in Crohn’s disease. The presence and mechanisms that might regulate the ER stress response in subepithelial myofibroblasts (SEMFs) and its role in the development of fibrosis in patients with Crohn’s disease have not been examined. Methods Subepithelial myofibroblasts were isolated from the affected ileum and normal ileum of patients with each Montreal phenotype of Crohn’s disease and from normal ileum in non-Crohn’s subjects. Binding of GRP78 to latent TGF-β1 and its subcellular trafficking was examined using proximity ligation-hybridization assay (PLA). The effects of XBP1 and ATF6 on TGF-β1 expression were measured using DNA-ChIP and luciferase reporter assay. Endoplasmic reticulum stress components, TGF-β1, and collagen levels were analyzed in SEMF transfected with siRNA-mediated knockdown of DNMT1 and GRP78 or with DNMT1 inhibitor 5-Azacytidine or with overexpression of miR-199a-5p. Results In SEMF of strictured ileum from patients with B2 Crohn’s disease, expression of ER stress sensors increased significantly. Tunicamycin elicited time-dependent increase in GRP78 protein levels, direct interaction with latent TGF-β1, and activated TGF-β1 signaling. The TGFB1 DNA-binding activity of ATF-6α and XBP1 were significantly increased and elicited increased TGFB1 transcription in SEMF-isolated from affected ileum. The levels of ER stress components, TGF-β1, and collagen expression in SEMF were significantly decreased following knockdown of DNMT1 or GRP78 by 5-Azacytidine treatment or overexpression of miR-199a-5p. Conclusions Endoplasmic reticulum stress is present in SEMF of patients susceptible to fibrostenotic Crohn’s disease and can contribute to development of fibrosis. Targeting ER stress may represent a novel therapeutic target to prevent fibrosis in patients with fibrostenotic Crohn’s disease.

2020 ◽  
Vol 26 (Supplement_1) ◽  
pp. S35-S35
Author(s):  
Chao Li ◽  
John Kuemmerle

Abstract Epigallocatechin-3-gallate (EGCG) has multifaceted roles in the preclinical treatment of diseases including liver and lung fibrosis. EGCG has also been tested with fewer reported side effects than therapeutic drugs. Previously we showed that increase in endoplasmic reticulum (ER) stress response in subepithelial myofibroblasts (SEMF) contributes to activation of TGF-β1 and resultant intestinal fibrosis in patients with fibrostenotic Crohn’s disease. Moreover, different migratory potential of myofibroblasts isolated from inflamed, fibrostenotic, or fistulized Crohn’s disease mucosa could be an explanation for impaired or excess wound healing and subsequently for fistula or fibrosis in patients with Crohn’s disease. To investigate the effect of EGCG on ER stress-mediated wound healing process, SEMF were isolated from normal ileum and affected ileum in the same patient with Crohn’s disease. Cells were cultured and treated with EGCG (10 μg/ml), AG1024 (a tyrosine kinase inhibitor, 6 μM), U1026 (an ERK inhibitor, 6 μM), LY294002 (a PI3K inhibitor, 10 μM), SB202190 (a p38 inhibitor, 50 nM), 4-PBA (a chemical chaperone, 10 μg/ml), and MG132 (a NF-KB inhibitor, 3 μM) for 2 hours in serum free medium. Cell lysates were obtained for Western blot analysis. An ER stress agonist tunicamycin (5 μg/ml) was incubated with SEMF for different time points. Wound healing assay was used in a cell monolayer, capturing the images at the beginning and at regular intervals during cell migration to close the wound, and comparing the images to quantify the migratory potential of the cells. In vivo effect of EGCG was tested in a murine TNBS colitis model and observed by Storz Coloview standard operating procedures. Here we showed that EGCG further decreased endogenous GRP78 protein expression by 18∼29±1.5% in SEMF compared to that treated with different inhibitors targeting other non-ER stress signals. EGCG prevented tunicamycin-induced migratory potential of SEMF isolated from normal ileum by 40±2.5%, 65±3.3% after 48 and 72 hours, as well as cell proliferation by 85±3.3%, 120±6.1% after 48 and 72 hours, respectively. Moreover, EGCG also further decreased cell migratory potential of SEMF isolated from affected ileum by 15±1.2% and 50±1.8% compared to the control group after 48 and 72 hours, respectively. Coloview showed that EGCG decreased inflammatory activity in the mice colon compared to TNBS colitis group after 8-week treatment. Ongoing study includes methylene blue staining of the colonic mucosa during endoscopy, endoscopic scoring of inflammation activity, and trichrome staining of collagen production in a colonic biopsy. Taken together, EGCG alleviates ER Stress response, leads to greater inhibition of migratory potential of SEMF, and decreases TGF-β1 and collagen productions, which is the major molecular feature of fibrosis.


2018 ◽  
Vol 12 (supplement_1) ◽  
pp. S084-S084
Author(s):  
S Hu ◽  
N Bletard ◽  
C Massot ◽  
N Pierre ◽  
F Quesada Calvo ◽  
...  

2020 ◽  
Vol 14 (Supplement_1) ◽  
pp. S143-S144
Author(s):  
B Rodrigues ◽  
L B Pascoal ◽  
A Coope ◽  
M L S Ayrizono ◽  
M G Camargo ◽  
...  

Abstract Background The endoplasmic reticulum (ER) is responsible for the synthesis and processing of secretory and membrane proteins. In some cases, proteins cannot reach their final conformation and they remain unfolded in the ER lumen. The accumulation of unfolded proteins leads to a state of stress in the ER (ER stress) that is considered toxic to the cells. As a result, cells may respond by driving the proteins to degradation, pausing the transcription process, or even inducing apoptosis.1 ER stress has recently been linked to the exacerbation of the inflammatory process in the pathogenesis of Crohn’s disease (CD).2 Therefore, our aim was to evaluate the effect of a chemical inhibitor on the activation of ER stress pathways and its modulation of pro-inflammatory cytokines. Methods After approval of a local Ethics Committee, biopsies of intestinal mucosa were collected by colonoscopy from patients with CD (CD group) and from patients without inflammatory bowel diseases (control group). Explant culture was performed to evaluate the occurrence of ER stress and was treated with a chemical ER stress inhibitor. Non-parametric tests were performed for statistical analysis adopting p < 0.05 as significant value. Results Samples were collected from 10 patients with active CD (CDEIS ≥5) and six control patients. After cell culture, a significant difference was observed in the activation of the main ER stress pathway in the CD group when compared with control group. After treatment with a chemical inhibitor, there was significant decrease in the expression of genes responsible for the activation of ER stress. In addition, a decrease in the expression of inflammatory cytokines was observed after treatment. Conclusion The use of a chemical inhibitor has been shown to be effective in significantly decreasing the activation of ER stress and to modulate the inflammation in CD. The activation of the main ER stress pathways may contribute to the inflammatory process in CD, and its blockade suggests a potential new target in the treatment of CD. References


2021 ◽  
Author(s):  
Lin Fang ◽  
Mengcheng Hu ◽  
Fei Xia ◽  
wenxia Bai

Abstract Background: Long non-coding RNAs (lncRNAs) have different functions in different diseases. There is seldom research on the functions of lncRNAs in Crohn’s disease (CD). By RNA-seq technology, we identify a lncRNA associated with Crohn's disease. However, the mechanism of lncRNA regulation remains unknown. This study aimed to determine the association of LINC01272 with epithelial cell-mesenchymal transition and the underlined mechanism in CD.Methods: RNA is detected by qRT-PCR. Interaction of protein and RNA was determined by RNA binding protein immunoprecipitation. Luciferase reporter assays were used to detect the targeted miRNA of LINC01272. Tissue fibrosis was observed by Masson and HE staining. The protein expression is determined by western blot and immunofluorescence. Results: LINC01272 was highly expressed in patients with CD. Knockdown of LINC01272 inhibited TGF-β1-induced epithelial-mesenchymal transition (EMT). Additionally, LINC01272 regulated TGF-β1 induced EMT by miR-153-5p axis and knockdown of LINC01272 inhibited EMT in the CD mice in vivo. Conclusion: LINC01272 activated epithelial-mesenchymal transition through miR-153-5p in CD.


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