Human β-defensin-3 reduces excessive autophagy in intestinal epithelial cells and in experimental necrotizing enterocolitis

Abstract

Necrotizing enterocolitis (NEC) is a leading cause of mortality in preterm newborns. Intestinal barrier dysfunction is one key event in NEC pathogenesis. Human β-defensin-3 (hBD3), one member of cationic host defence peptides, was reported to reduce the development of necrotizing enterocolitis in a neonatal rat model. And autophagy was induced in the intestine of human and animals with NEC. We hypothesized that regulation of autophagy might play a critical role in hBD3-mediated protection against NEC injury. Autophagy activity was evaluated both in intestinal epithelial cells and in NEC models. Newborn Sprague-Dawley rats were divided randomly into four groups: Control + NS, Control + rapamycin, NEC + NS, and NEC + hBD3. Body weight, histological score, survival time, enterocyte migration and mucosal barrier were recorded. Our results showed that hBD3 pretreatment could effectively inhibit autophagy activity in cultured IEC-6 and Caco2 enterocytes, and CXCR4 might be involved in hBD3-mediated autophagy suppression. Moreover, hBD3-induced inhibition of autophagy significantly promoted the intestinal epithelial cell migration by wound healing assay and transwell migration assay. In the rat model of NEC, hBD3 could noticeably reduce the expression of autophagy-activated proteins, down-regulate the expression of inflammatory mediators, and promote the mucosal integrity. Our data suggest an additional role of hBD3-mediated protection against intestinal mucosal injury: inhibition of over-activated autophagy in enterocytes.

β-Carotene Attenuates Apoptosis and Autophagy via PI3K/AKT/mTOR Signaling Pathway in Necrotizing Enterocolitis Model Cells IEC-6

“…p62, as a marker of autophagy flux, is reduced in the last phase of autophagy, which is negatively correlated with autophagy activity level [36]. In the rat NEC model, autophagy in epithelial cells can be observed by significant activation of autophagy [37]. Importantly, Yang et al reported that β-carotene alleviates LPS-induced intestinal inflammation in rats, which may be related to autophagy [38].…”

Identification and Validation of Autophagy-Related Genes in Necrotizing Enterocolitis

“…Moreover, Human β-defensin-3 (hBD3) reduces excessive autophagy in intestinal epithelial cells and NEC. Furthermore, hBD3 treatment can significantly induce intestinal epithelial cell migration and reduce the severity and mortality of the NEC model in neonatal rats ( 16 ). Similarly, erythropoietin (Epo), a component of breast milk, protects intestinal epithelium from excessive autophagy and apoptosis in NEC mice ( 24 ).…”

“…Recently, autophagy has been linked to inflammatory bowel disease (IBD). Moreover, autophagy has also been reported to be activated respectively in the intestine tissues of patients with NEC and the ileum tissues of NEC rats ( 16 ). However, autophagy-related genes in NEC are unrecognized and thus require deeper exploration.…”

Intestinal Epithelial Barrier Function and Necrotizing Enterocolitis

“…In a rat model of NEC, treatment with human beta-defensin-3 improved NEC and promoted mucosal integrity by reducing inflammatory mediators and reduced autophagyactivated proteins. 32 Furthermore, rats treated with Bifidobacterium increased beta-defensin-2 which provided protection from NEC. 33 However, whether deficient production of these antimicrobial peptides contributes to NEC remains unknown.…”