A role for miRNAs in the regulation of brown adipose tissue whitening in goats (Capra Hircus).

ABSTRACT

A study of the mechanism of and metabolic regulation of brown adipose tissue (BAT) production is important for improving the survival rate of young animals. In the present study, we observed that perirenal adipose tissue in goats undergoes a rapid BAT whitening after birth. However, the underlying regulatory mechanism remains unknown. To address this further, we investigated the role of miRNAs in regulating the whitening process of BAT in goats. First, we identified the dynamic expression profiles of miRNAs during the whitening of BAT in Dazu black goat using RNA-seq. We identified a total of 1374 miRNAs, including 408 existing miRNAs, 693 known miRNAs, and 273 novel miRNAs. By analysis of the differentially expressed miRNAs (DE miRNAs), we found that 102 highly expressed miRNAs, including chi-miR-144-3p, chi-miR-144-5p, chi-miR-378-5p, chi-miR-136-3p, chi-miR-381, chi-miR-323b, chi-miR-1197-3p, chi-miR-411b-3p, and chi-miR-487a-3p, were enriched in BAT. In addition, 60 highly expressed miRNAs, including chi-miR-184, chi-miR-193a, chi-miR-193b-3p, chi-let-7c-5p, and chi-let-7e-5p, were enriched in white fat-like tissue. An analysis of miRNAs that were linearly downregulated (profile 0) or linearly upregulated (profile 19) over the D0-D28 period found that these DE miRNAs were mainly enriched in the Hippo signaling pathway, Cytokine-cytokine receptor interactions, and the TGF-beta signaling pathway. Furthermore, we confirmed that chi-let-7e-5p promotes the proliferation and differentiation of brown adipocytes. These results should facilitate a better understanding of the molecular regulation of miRNAs involved in BAT whitening in goats.

Goat kids born during the cold season are prone to perishing due to harsh temperatures. However, implementing artificial warming and increasing heat production in goat kids can enhance their survival chances. Newborn Goat kids possess significant amounts of brown adipose tissue (BAT) in the perirenal region, and BAT is known to play a vital role in regulating body temperature via non-shivering thermogenesis. A preliminary investigation revealed that the perirenal adipose tissue in goat kids undergoes BAT whitening during the first month of life. However, the mechanism underlying BAT whitening remains unknown. Previous research suggests that miRNAs serve as critical regulators of metabolic homeostasis in adipose tissue. Thus, a comprehensive screening of the expression profile of miRNAs during BAT whitening in Dazu black goats and subsequent identification of miRNAs that regulate BAT thermogenesis should provide a foundation for future research on BAT development and regulation in goats.