Background: No doubt that the corpus luteum (CL) plays a vital role in the regulation of female cyclicity in mammals.
The scenarios among microRNAs (miRNAs) and their target genes and steroid hormones {estradiol (E2) and progesterone
(P4)} are required for better understanding the molecular regulation of CL during its formation, maturation,
and regression. We aimed to (I) study the changes in the relative abundance of miR-205, miR-26a-5p, miR-17-5p, and
let-7b-5p and their target genes: LHCGR, CASP3, PCNA, AMH, and PLA2G3, during different stages of corpus luteum in
Egyptian buffaloes, and (II) and to address different scenarios between steroid concentrations in the serum and the
expression pattern of selected miRNAs and their targets.
Methods: The paired ovaries and blood samples were collected from apparently healthy 50 buffalo cows at a private
abattoir. The ovaries bearing CL were macroscopically divided according to their morphological structure and color
into hemorrhagic (CLH), developing (CLD), mature (CLM), regressed (CLR), and albicans (CLA). Small pieces from different
stages of CL (CLH, CLD, CLM, CLR, and CLA) were cut and immediately kept at − 80 °C for total RNA isolation and
qRT-PCR. The serum was separated for steroid level estimation.
Results: The LHCGR was expressed during different stages of CL, and the peak of expression was at the mid-luteal
stage. The CASP3 revealed a stage-specific response at different stages of CL. The PCNA has an essential role in cellular
proliferation in buffaloes CL. Both expression patterns of PLA2G3 and AMH were found over the various developmental
and regression stages. It was noticed that miR-205 is conserved to target LHCGR and CASP3 transcripts. Moreover,
CASP3 and AMH were targeted via miR-26a-5p. Additionally, the CASP3 and PLA2G3 were targeted via let-7b-5p. The
P4 level reached its peak during CLM. There were positive and negative strong correlations between miRNAs (miR-
26a-5p and miR-205), target genes (LHCGR and CASP3) during different stages of CL, and steroid hormones in the
serum.
Conclusions: Taken together, the orchestrated pattern among miRNAs, target genes, and steroid hormones is essential
for maintaining the proper development and function of CL in buffalo cows. |
