NTPDase8 protects mice from intestinal inflammation by limiting P2Y₆ receptor activation: identification of a new pathway of inflammation for the potential treatment of IBD

Abstract

ObjectiveNucleotides are danger signals that activate inflammatory responses via binding P2 receptors. The nucleoside triphosphate diphosphohydrolase-8 (NTPDase8) is an ectonucleotidase that hydrolyses P2 receptor ligands. We investigated the role of NTPDase8 in intestinal inflammation.DesignWe generated NTPDase8-deficient (Entpd8–/–) mice to define the role of NTPDase8 in the dextran sodium sulfate (DSS) colitis model. To assess inflammation, colons were collected and analysed by histopathology, reverse transcriptase-quantitative real-time PCR (RT-qPCR) and immunohistochemistry. P2 receptor expression was analysed by RT-qPCR on primary intestinal epithelium and NTPDase8 activity by histochemistry. The role of intestinal P2Y6 receptors was assessed by bone marrow transplantation experiments and with a P2Y6 receptor antagonist.ResultsNTPDase8 is the dominant enzyme responsible for the hydrolysis of nucleotides in the lumen of the colon. Compared with wild-type (WT) control mice, the colon of Entpd8–/– mice treated with DSS displayed significantly more histological damage, immune cell infiltration, apoptosis and increased expression of several proinflammatory cytokines. P2Y6 was the dominant P2Y receptor expressed at the mRNA level by the colonic epithelia. Irradiated P2ry6–/– mice transplanted with WT bone marrow were fully protected from DSS-induced intestinal inflammation. In agreement, the daily intrarectal injection of a P2Y6 antagonist protected mice from DSS-induced intestinal inflammation in a dose-dependent manner. Finally, human intestinal epithelial cells express NTPDase8 and P2Y6 similarly as in mice.ConclusionNTPDase8 protects the intestine from inflammation most probably by limiting the activation of P2Y6 receptors in colonic epithelial cells. This may provide a novel therapeutic strategy for the treatment of inflammatory bowel disease.

Ghrelin Inhibits Intestinal Epithelial Cell Apoptosis Through the Unfolded Protein Response Pathway in Ulcerative Colitis

“…To verify the antiapoptotic role of ghrelin in vivo, we used ghrelin to treat the DSS-and TNBS-induced colitis models, respectively. As previously reported, the colon of mice treated with DSS or TNBS displayed more significant apoptosis (Arab et al, 2021;Salem et al, 2021) (Figures 3A, 3B). Compared with the treatment group, ghrelin reduced the colon cell apoptosis in a dose-dependent manner, and such an antiapoptotic effect of ghrelin could be reversed by [D-lys3]-GHRP-6 ( Figures 3A,B).…”

Redox-dependent internalization of the purinergic P2Y 6 receptor limits colitis progression

“…P2Y 6 R abundance has been reported to increase in experimental colitis in mice, and the inhibition of P2Y 6 R by MRS2578 or the deletion of P2Y 6 R specifically in intestinal epithelial cells improves symptoms and is protective against intestinal inflammation ( 8 , 15 ). Consistent with those reports, we found that global P2Y 6 R deletion attenuated DSS-induced colitis, supporting the involvement of P2Y 6 R in the exacerbation of inflammation.…”

“…Cys 220 modification of P2Y 6 R protects mice against DSS-induced colitis It has been reported that P2Y 6 R participates in IBD such as Crohn's disease and ulcerative colitis (8,15) and that dietary supplementation with natural ITCs exerts therapeutic anti-inflammatory effects (16). To determine whether modification of P2Y 6 R at Cys 220 affects intestinal inflammation in vivo, we performed experiments in whole-body P2Y 6 R knockout and P2Y 6 R (C220S) knockin mice in which colitis was induced by dextran sulfate sodium (DSS).…”

“…In humans, P2Y 6 R is highly abundant in a wide range of inflammatory cells, including macrophage and T cells. Because of its proinflammatory activity, P2Y 6 R has been implicated in the pathogenesis of inflammatory bowel disease (IBD)–mediated intestinal damage ( 7 , 8 ). The third intracellular loop of P2Y 6 R lacks the serines and threonines that are involved in β-arrestin–dependent internalization, and the C terminus has only a single threonine.…”

Purinergic receptors modulators: An emerging pharmacological tool for disease management

“…In a recent study, it was found that NTPDase8 plays a crucial role in protecting intestinal inflammation by limiting the purinergic signaling mediated through the P2Y 6 receptor in colonic epithelial cells. This may be a novel therapeutic approach for the treatment of IBD 180 …”