Functional Variants Surrounding Endothelin 2 Are Associated With Mycobacterium avium Subspecies paratuberculosis Infection

Abstract

Bovine paratuberculosis, caused by Mycobacterium avium subspecies paratuberculosis (MAP), continues to impact the dairy industry through increased morbidity, mortality, and lost production. Although genome-wide association analyses (GWAAs) have identified loci associated with susceptibility to MAP, limited progress has been made in identifying mutations that cause disease susceptibility. A 235-kb region on Bos taurus chromosome 3 (BTA3), containing a 70-kb haplotype block surrounding endothelin 2 (EDN2), has previously been associated with the risk of MAP infection. EDN2 is highly expressed in the gut and is involved in intracellular calcium signaling and a wide array of biological processes. The objective of this study was to identify putative causal mutations for disease susceptibility in the region surrounding EDN2 in Holstein and Jersey cattle. Using sequence data from 10 Holstein and 10 Jersey cattle, common variants within the 70-kb region containing EDN2 were identified. A custom SNP genotyping array fine-mapped the region using 221 Holstein and 51 Jersey cattle and identified 17 putative causal variants (P < 0.01) located in the 5′ region of EDN2 and a SNP in the 3′ UTR (P = 0.00009) associated with MAP infection. MicroRNA interference assays, mRNA stability assays, and electrophoretic mobility shift assays were performed to determine if allelic changes at each SNP resulted in differences in EDN2 stability or expression. Two SNPs [rs109651404 (G/A) and rs110287192 (G/T)] located within the promoter region of EDN2 displayed differential binding affinity for transcription factors in binding sequences harboring the alternate SNP alleles. The luciferase reporter assay revealed that the transcriptional activity of the EDN2 promoter was increased (P < 0.05) with the A allele for rs109651404 and the G allele for rs110287192. These results suggest that the variants rs109651404 and rs110287192 are mutations that alter transcription and thus may alter susceptibility to MAP infection in Holstein and Jersey cattle.

A novel missense variant in endothelin‐2 (EDN2) causes a growth and respiratory lethal syndrome in bovine

“…EDN2 is a transcriptionally regulated 177 amino acid peptide implicated in vascular homeostasis, but also in female reproduction (Ko et al, 2012), gastrointestinal function (Chang et al, 2013; Takizawa et al, 2005), immune cell function (Grimshaw et al, 2002), heart failure (Brown et al, 2000) and various cancers (Ling et al, 2013). In bovines, EDN2 expression has been found to be affected in lung epithelial cells during respiratory diseases, specifically in paratuberculosis infection (Çınar et al, 2020; Kiser et al, 2021), and in bronchial epithelial cells after exposure to viral (Herpes virus) and bacterial ( Mannheimia haemolytica ) pathogens (N'jai et al, 2013). Thus, the lesions compatible with a respiratory viral process found in the five necropsied calves could have been facilitated by the alteration of the expression of EDN2 triggering bovine GRL.…”

Genome-wide association studies for the identification of cattle susceptible and resilient to paratuberculosis

“…Although GWAS have allowed the identification of SNPs associated with the susceptibility to MAP infection, the genes through which these variants exert their effects are unknown, and only a few functional mutations for PTB have been identified ( 50 , 51 ). Expression quantitative trait loci (eQTLs) are genetic variants located in gene regulatory regions that alter gene expression.…”

Genetic Diversity and Population Structure for Resistance and Susceptibility to Mastitis in Braunvieh Cattle

“…For RSM, 40% of the markers belong to EDN2 and HIVEP3, candidate genes associated with immune processes, such as intracellular and sequential signaling of immunoglobulin receptors. Because of their immunologic nature, these genes have not been directly selected for; however, at the farm level there is a rising concern for improving their animals for genes associated with diseases that could be prevented, such as paratuberculosis and clinic mastitis [8,52].…”