The Insect Peptide CopA3 Increases Colonic Epithelial Cell Proliferation and Mucosal Barrier Function to Prevent Inflammatory Responses in the Gut

Abstract

The epithelial cells of the gut form a physical barrier against the luminal contents. The collapse of this barrier causes inflammation, and its therapeutic restoration can protect the gut against inflammation. EGF enhances mucosal barrier function and increases colonocyte proliferation, thereby ameliorating inflammatory responses in the gut. Based on our previous finding that the insect peptide CopA3 promotes neuronal growth, we herein tested whether CopA3 could increase the cell proliferation of colonocytes, enhance mucosal barrier function, and ameliorate gut inflammation. Our results revealed that CopA3 significantly increased epithelial cell proliferation in mouse colonic crypts and also enhanced colonic epithelial barrier function. Moreover, CopA3 treatment ameliorated Clostridium difficile toxin As-induced inflammation responses in the mouse small intestine (acute enteritis) and completely blocked inflammatory responses and subsequent lethality in the dextran sulfate sodium-induced mouse model of chronic colitis. The marked CopA3-induced increase of colonocyte proliferation was found to require rapid protein degradation of p21 Cip1/Waf1 , and an in vitro ubiquitination assay revealed that CopA3 directly facilitated ubiquitin ligase activity against p21 Cip1/Waf1 . Taken together, our findings indicate that the insect peptide CopA3 prevents gut inflammation by increasing epithelial cell proliferation and mucosal barrier function.

The American cockroach peptide periplanetasin‐4 inhibits Clostridium difficile toxin A‐induced cell toxicities and inflammatory responses in the mouse gut

“…As shown in Figure (A), toxin A caused marked mucosal damage, but this effect was markedly abolished by cotreatment with Peri‐4. Numerous reports have shown that injection of toxin A into the gut lumen triggers the production of proinflammatory cytokines, including IL‐6 . As shown in Figure (B), the IL‐6 levels were higher in toxin A‐injected tissues compared with controls, but this increase was significantly reduced by cotreatment with Peri‐4.…”

“…C. difficile toxin A is known to cause cell rounding by disaggregating actin filaments; this occurs through the enzymatic activity of the toxin, which directly monoglucosylates Rho family proteins in the cytosol [5,[7][8][9]28]. We recently reported that CopA3 peptide directly interacts with/activates ubiquitin ligases specifically located in the cytosol of human colonocytes [29]. Based on this previous finding and our novel observation that Peri-4 rescues the cell rounding caused by toxin A, we speculate that Peri-4 may enter the cytosol and interfere with the ability of toxin A to form an enzyme-substrate complex with Rho family proteins, thereby inhibiting the ability of the toxin to cause cytoskeletal disruption.…”

“…Many insect peptides have been reported to show selective antibacterial activities and/or biological effects on various mammalian cell types [10,29,32,33,38], suggesting that these peptides can specifically interact with target cells (e.g. via membrane receptors) [10,32].…”

The American Cockroach Peptide Periplanetasin-2 Blocks Clostridium Difficile Toxin A-Induced Cell Damage and Inflammation in the Gut

“…The Peri-2 peptide (15-mer (YPCKLNLKLGKVPFH), from the American cockroach Periplaneta americana Linnaeus) was synthesized by AnyGen (Korea). The C-terminus of the peptide was synthesized as an amide to neutralize the negative charge created by the Cterminal COOH and prevent enzyme degradation [13,[24][25][26]. The peptide was purified by reverse-phase high-performance liquid chromatography (HPLC) using a Capcell Pak C18 column (Shiseido, Japan) and eluted with a linear gradient of wateracetonitrile (0-80%) containing 0.1% trifluoroacetic acid (45% recovery).…”

Intracellular synthesis of gold nanoparticles by Gluconacetobacter liquefaciens for delivery of peptide CopA3 and ginsenoside and anti-inflammatory effect on lipopolysaccharide-activated macrophages

“…It has been reported to exert antibacterial effects against various pathogenic bacteria [24] and selective anticancer on human gastric cancer cells [25]. CopA3 also ameliorated inflammatory responses in the gut [26] and lipopolysaccharide (LPS)induced macrophage activation [27].…”