Effect of a matrix metalloproteinase sequestering biomaterial on Caco-2 epithelial cell barrier integrity in vitro

Transcription factor paired related homeobox 1 (PRRX1) activates matrix metalloproteinases (MMP)13, which promotes the dextran sulfate sodium-induced inflammation and barrier dysfunction of NCM460 cells

Paired related homeobox 1 (PRRX1) is a newly identified transcription factor that regulates the expression of various genes. We aimed to investigate the roles of PRRX1 and Matrix metalloproteinases (MMP)13 in dextran sulfate sodium (DSS)-induced inflammation and barrier dysfunction of NCM460 cells. PRRX1 expression in the mucosal tissues of patients with ulcerative colitis was analyzed using the GSE87466 microarray. PRRX1 and MMP13 expression was examined using Western blotting and RT-qPCR following the exposure of the NCM460 cells to DSS. The JASPAR database was used to predict the binding sites of PRRX1 to the MMP13 promoter, which was verified by luciferase reporter and chromatin immunoprecipitation assays. MMP13 expression was then detected following PRRX1 silencing or overexpression. The levels of inflammatory factors were determined using ELISA. Finally, the expression of intestinal barrier function-related proteins was evaluated using Western blotting and cellular permeability was detected by Transepithelial electrical resistance. PRRX1 was upregulated in the mucosal tissue samples of patients with UC. DSS induction upregulated PRRX1 and MMP13 expression. PRRX1 bound to the promoter of MMP13, which was further supported by the decreased expression of MMP13 observed following PRRX1 knockdown and its increased expression following PRRX1 overexpression. Furthermore, PRRX1 deletion decreased TNF-α, IL-1β and IL-6 levels in the DSS-challenged NCM460 cells, which were subjected to MMP13 overexpression. Moreover, PRRX1 silencing upregulated ZO-1, occludin and claudin-1 expression and elevated the TEER value, whereas MMP13 overexpression attenuated these effects. Collectively, PRRX1 activates MMP13, which in turn promotes the DSS-induced inflammation and barrier dysfunction of NCM460 cells.

Matrix metalloproteinases in inflammatory bowel disease: an update

Matrix metalloproteinases (MMPs) are known to be upregulated in inflammatory bowel disease (IBD) and other inflammatory conditions, but while their involvement is clear, their role in many settings has yet to be determined. Studies of the involvement of MMPs in IBD since 2006 have revealed an array of immune and stromal cells which release the proteases in response to inflammatory cytokines and growth factors. Through digestion of the extracellular matrix and cleavage of bioactive proteins, a huge diversity of roles have been revealed for the MMPs in IBD, where they have been shown to regulate epithelial barrier function, immune response, angiogenesis, fibrosis, and wound healing. For this reason, MMPs have been recognised as potential biomarkers for disease activity in IBD and inhibition remains a huge area of interest. This review describes new roles of MMPs in the pathophysiology of IBD and suggests future directions for the development of treatment strategies in this condition.

Matrix metalloproteinase 13 modulates intestinal epithelial barrier integrity in inflammatory diseases by activating TNF

Several pathological processes, such as sepsis and inflammatory bowel disease (IBD), are associated with impairment of intestinal epithelial barrier. Here, we investigated the role of matrix metalloproteinase MMP13 in these diseases. We observed that MMP13^−/− mice display a strong protection in LPS- and caecal ligation and puncture-induced sepsis. We could attribute this protection to reduced LPS-induced goblet cell depletion, endoplasmic reticulum stress, permeability and tight junction destabilization in the gut of MMP13^−/− mice compared to MMP13^+/+ mice. Both in vitro and in vivo, we found that MMP13 is able to cleave pro-TNF into bioactive TNF. By LC-MS/MS, we identified three MMP13 cleavage sites, which proves that MMP13 is an alternative TNF sheddase next to the TNF converting enzyme TACE. Similarly, we found that the same mechanism was responsible for the observed protection of the MMP13^−/− mice in a mouse model of DSS-induced colitis. We identified MMP13 as an important mediator in sepsis and IBD via the shedding of TNF. Hence, we propose MMP13 as a novel drug target for diseases in which damage to the gut is essential.