Recombinant Porcine R-Spondin 1 Facilitates Intestinal Stem Cell Expansion along the Crypt-Villus Axis through Potentiating Wnt/β-Catenin Signaling in Homeostasis and Deoxynivalenol Injury

R-spondin 1 (RSPO1) is a ligand for the intestinal stem cell (ISC) marker Lgr5 in the crypt, which functions to amplify canonical Wnt signaling to stimulate the division of ISCs. Despite the crucial role of recombinant human RSPO1 (rhRSPO1) in homeostasis and regeneration, little is known about RSPO1 among different species. Here, we cloned the porcine RSPO1 (pRSPO1) gene and obtained rpRSPO1 protein through the expression system of the recombinant Escherichia coli Rosetta (DE3) chemical competent cells. Using the in vitro IPEC-J2 model that combines cell proliferation evaluation approaches, we identified the rpRSPO1 activity in stimulating jejunal epithelial cells. And upon deoxynivalenol challenge in mice, we found that rpRSPO1 ameliorated their growth retardation and jejunal epithelial integrity. Importantly, the ISCs in the jejunum had greater proliferation and differentiation potential that was accompanied by Wnt/beta-catenin pathway activation after rpRSPO1 modulation. Subsequently, the jejunal organoids expanded from these ISCs ex vivo presented robust growth advantages. And the rpRSPO1 was able to guide Wnt/beta-catenin activity to increase ISC activity. Our work systematically demonstrates that rpRSPO1 facilitates ISC expansion by potentiating Wnt/beta-catenin signaling during homeostasis and responding to deoxynivalenol perturbations.

Automated summary

This study cloned the porcine RSPO1 gene and obtained rpRSPO1 protein, and demonstrated the stimulatory effect of rpRSPO1 on jejunal epithelial cell proliferation using in vitro and in vivo models. It also showed that rpRSPO1 could ameliorate growth retardation and maintain epithelial integrity in mice, and increase ISC activity by activating the Wnt/β-catenin pathway.