Important progress has been made in immunological research on the intestines infected with porcine coronavirus

Recently, the innovative team of animal diarrhea disease prevention and control of the veterinary institute used single-cell sequencing technology to systematically analyze the functional changes of different intestinal cells after infection with porcine epidemic diarrhea virus (PEDV), and the relevant research results were titled "Identification of Cell Types and Transcriptome Landscapes of Porcine Epidemic Diarrhea Virus-Infected.
" Porcine Small Intestine Using Single-Cell RNA Sequencing" was published online in The Journal of Immunology
, an international authoritative journal in the field of immunology.
Professor Li Bin and Professor Fan Huiying of South China Agricultural University are co-corresponding authors of the paper, and Associate Professor Fan Baochao and Dr.
Zhou Jinzhu are co-first authors
of the paper.

Porcine epidemic diarrhea virus (PEDV) is one of the most important pathogens causing diarrhea in piglets, with a fatality rate of 100% for newborn piglets, causing huge economic losses
to the global pig industry.
However, the pathogenesis of the virus is still not fully understood, especially the functional effect of PEDV infection on different cell types in the intestines of piglets, the target organ, is not clear
.

In this work, the researchers performed single-cell sequencing analysis of the jejunal segment of piglets after PEDV infection, and identified representative marker molecules of different cell types such as piglet intestinal epithelial cells, goblet cells, Tuft cells, enterosecretory cells and stem cells, as well as immune-related B cells, plasma cells, CD8+ T cells, Th17 cells, and myeloid cells.
DNAH11 was newly identified as a specific marker molecule for piglet intestinal Tuft cells
.
By identifying the intestinal cell types infected with PEDV, it was found that in addition to intestinal epithelial cells, goblet cells and Tuft cells were also infectious with PEDV
.

Identification of intestinal cell types and immune cell types in piglet jejunal segments

Through transcriptional analysis of different cell types, apoptosis and MAPK signaling pathways were found in viral upregulated intestinal epithelial cells, goblet cells, Tuft cells and enteroendocrine cells.
The tight junction and adhesion junction pathways of goblet cells, tuft cells, and enteroendocrine cells are significantly increased
.
Transcriptional analysis of different immune cells found that viral infection led to reduced differentiation of T cell receptors, Th1 and Th2 cells in T and Th17 cells, and decreased
B cell receptors and IgA production signaling pathways in B cells.

Through in-depth analysis of goblet cells after PEDV infection, the researchers found that PEDV infection significantly downregulated the expression
of various mucin molecules in goblet cells.
In vitro, using the goblet cell line of human colon cancer as a model, PEDV infection significantly reduced the expression of important intestinal mucin MUC2 and other mucus components FCGBP, CLCA1 and AGR2, and had a limiting effect
on the exosome of MUC2.

PEDV infection downregulates mucin expression in goblet cells

Through the analysis of antimicrobial peptide-related genes, it was found that PEDV infection significantly upregulated the expression of REG3G in intestinal epithelial cells, and REG3G significantly inhibited PEDV replication and acted on the intracellular replication stage of the viral replication cycle.
Further mechanistic studies have found that PEDV infection induces the STAT3 phosphorylation pathway to upregulate REG3G expression by upregulating IL-33 expression
.

Analysis of the mechanism of upregulation of antimicrobial peptide REG3G by PEDV infection and its antiviral effect

In this study, the intestines of piglets infected with PEDV were analyzed by single-cell technology for the first time, different cell types and representative markers of piglet intestines were clarified, and the changes of PEDV infection on the function of different cell types in the intestine were systematically analyzed, and the regulatory effect of PEDV infection on goblet cell mucin molecules, as well as the antiviral effect and upregulation mechanism
of antibacterial peptide REG3G.
A series of findings will further deepen the understanding of the pathogenesis of PEDV at the animal organism level, and will provide new ideas
for the development of new control strategies.

The research has been funded
by the 14th Five-Year Plan National Key Research and Development Program, the National Natural Science Foundation of China, and the Natural Science Foundation of Jiangsu Province.