Yak miR-2285o-3p attenuates hypoxia-induced apoptosis by targeting caspase-3.

miRNAs are a class of hairpin-derived RNAs, 21-24 nucleotides in length, which are involved in a range of biological processes. The bta-miR-2285 family has over 40 members spanning the entire bovine genome. We previously found that bta-miR-2285o-3p was highly expressed in yak heart and lung when compared with cattle, which prompted us to investigate its potential function in high-altitude adaptation of yaks. In this study, we detected wide-spread high expression of bta-miR-2285o-3p in yak tissues. Further experiments revealed that the protein tyrosine phosphatase receptor type M (PTPRM) gene was the host gene of bta-miR-2285o-3p and that two linked SNPs in bta-mir-2285o precursor affected the biogenesis of mature miRNA (bta-miR-2285o-3p). Functional analysis in vitro indicated that bta-miR-2285o-3p attenuated hypoxia-induced apoptosis by targeting very low-density lipoprotein receptor (VLDLR), phosphatase and tensin homolog (PTEN) and caspase-3. Expression level analysis in vivo revealed the high negative Pearson's correlation between bta-miR-2285o-3p and caspase3 in yak, highlighting the potential important roles of bta-miR-2285o-3p in yak high-altitude adaptation. Our study provides a typical model for deciphering the function of miRNAs in environmental adaptation.