The Murine Reg3a Stimulated by Lactobacillus casei Promotes Intestinal Cell Proliferation and Inhibits the Multiplication of Porcine Diarrhea Causative Agent in vitro

Abstract

<i>Lactobacillus casei</i> (<i>L. casei</i>), a normal resident of the gastrointestinal tract of mammals, has been extensively studied over the past few decades for its probiotic properties in clinical and animal models. Some studies have shown that some bacterium of <i>Lactobacillus</i> stimulate the production of antimicrobial peptides in intestinal cells to clear enteric pathogens, however, which antimicrobial peptides are produced by <i>L. casei</i> stimulation and its function are still not completely understood. In this study, we investigated the changes of antimicrobial peptides' expression after intragastric administration of <i>L. casei</i> to mice. The bioinformatics analysis revealed there were nine genes strongly associated with up-regulated DEGs. But, of these, only the antimicrobial peptide m<i>Reg3a</i> gene was continuously up-regulated, which was also confirmed by qRT-PCR. We found out the m<i>Reg3a</i> expressed in engineering <i>E.coli</i> promoted cell proliferation and wound healing proved by CCK-8 assay and wound healing assay. Moreover, the tight junction proteins ZO-1 and E-cadherin in m<i>Reg3a</i> treatment group were significantly higher than that in the control group under the final concentration of 0.2 mg/ml both in Porcine intestinal epithelial cells (IPEC-J2) and Mouse intestinal epithelial cells (IEC-6) (<i>p</i> < 0.05). Surprisingly, the recombinant m<i>Reg3a</i> not only inhibited Enterotoxigenic <i>Escherichia coli</i> (ETEC), but also reduced the copy number of the piglet diarrheal viruses, porcine epidemic diarrhea virus (PEDV), porcine transmissible gastroenteritis virus (TGEV), and porcine rotavirus (PoRV), indicating the antimicrobial peptides m<i>Reg3a</i> may be feed additives to resist the potential of the intestinal bacterial and viral diarrhea disease.