Inhibition of CREB‐mediated ZO‐1 and activation of NF‐κB‐induced IL‐6 by colonic epithelial MCT4 destroys intestinal barrier function

Abstract

Objective Inflammatory bowel disease (IBD) is a disorder intestinal inflammation and impaired barrier function, associated with increased epithelial expression of monocarboxylate transporter 4 (MCT4). However, the specific non‐metabolic function and clinical relevance of MCT4 in IBD remain to be fully elucidated. Methods Lentivirus‐mediated overexpression of MCT4 was used to assess the role of MCT4 in transcriptionally regulating ZO‐1 and IL‐6 expression by luciferase assays, WB and ChIP. IP was used to analyse the effect of MCT4 on the interaction NF‐κB‐CBP or CREB‐CBP, and these MCT4‐mediated effects were confirmed in vivo assay. Results We showed that ectopic expression of MCT4 inhibited ZO‐1 expression, while increased pro‐inflammatory factors expression, leading to destroy intestinal epithelial barrier function in vitro and in vivo. Mechanistically, MCT4 contributed NF‐κB p65 nuclear translocation and increased the binding of NF‐κB p65 to the promoter of IL‐6, which is attributed to MCT4 enhanced NF‐κB‐CBP interaction and dissolved CREB‐CBP complex, resulting in reduction of CREB activity and CREB‐mediated ZO‐1 expression. In addition, treatment of experimental colitis with MCT4 inhibitor α‐cyano‐4‐hydroxycinnamate (CHC) ameliorated mucosal intestinal barrier function, which was due to attenuation of pro‐inflammation factors expression and enhancement of ZO‐1 expression. Conclusion These findings suggested a novel role of MCT4 in controlling development of IBD and provided evidence for potential targets of IBD.

Enteropathogenic Escherichia coli Infection Induces Diarrhea, Intestinal Damage, Metabolic Alterations, and Increased Intestinal Permeability in a Murine Model

“…(p<0.05, Figure 4J). Cyclic AMP Response Element-Binding protein (CREB) is another transcription factor involved on the transcription of inflammatory (such as IL-6, IL-2, and TNF-a) and antiinflammatory (IL-4, IL-10 and IL-13) mediators (Westbom et al, 2014;Zhang et al, 2019). To determine the levels of phosphorylated CREB (pCREB), its active form, we examined, but did not find a difference between EPEC-infected mice and controls on day 3 p.i.…”

Monocarboxylate Transporter 4 Triggered Cell Pyroptosis to Aggravate Intestinal Inflammation in Inflammatory Bowel Disease

“…As described in our pervious study ( 23 ), lentivirus of MCT4 overexpression was purchased from GenePharma (Shanghai, China) and used to infect HT-29 and CaCO2 cells to establish stable cell lines. Puromycin was from Sigma and used to select for stable cell line.…”

“…As described in our pervious study ( 23 ), the level of IL-1β was measured IL-18 in the serum and in the supernatants from HT-29 and CaCO2 cells with or without MCT4 overexpression which were collected and quantitated by sandwich ELISA according to the manufacturer’s instructions (Elabscience Biotechnology).…”

“…AMP-activated protein kinase (AMPK), a master regulator of energy metabolism, also improved gut epithelial differentiation and barrier function through histone modifications in the CDX2 promoter ( 21 ). In addition, we have previously demonstrated the monocarboxylate transporter 4 (MCT4) is evaluated in intestinal mucosal tissue of patients with IBD ( 22 ); further study demonstrated that the overexpression of MCT4 in intestinal epithelial cells (IECs) could significantly reduce cAMP-response element binding protein (CREB)-mediated ZO-1 expression, while it promotes NF-κB binding to IL-6 promoter, leading to induce IL-6 secretion ( 23 ). In this study, we revealed a novel role of MCT4 in cell pyroptosis by triggering NLRP3 inflammasome form, resulting in IL-1β secretion to aggravate intestinal inflammation.…”

EnteropathogenicEscherichia coli(EPEC) Infection Induces Diarrhea, Intestinal Damage, Metabolic Alterations and Increased Intestinal Permeability in a Murine Model

“…CREB is another transcription factor involved on the transcription of inflammatory (such as IL-6, IL-2 and TNF-α) and antiinflammatory (IL-4, IL-10 and IL-13) mediators [41,42]. To determine the levels of phosphorylated cyclic AMP -responsive element-binding protein (pCREB), its active form, the difference between EPEC-infected mice and controls on day 3 p.i.…”