New function of the CD44 gene: Lipid metabolism regulation in bovine mammary epithelial cells

摘要

The CD44 gene encodes a cell-surface glycoproteinthat participates in a variety of biological processessuch as cell interactions, adhesion, hematopoiesis, andtumor metastasis. We compared the transcriptome inbovine mammary epithelial cells (bMEC) of ChineseHolstein dairy cows producing milk of high and lowfat contents. Our results suggest that CD44 might bea candidate gene affecting milk fat synthesis. In thepresent study, the overexpression of the CD44 gene increasedthe contents of intracellular triglycerides (TG)and cholesterol (CHOL), whereas knockdown of theCD44 gene decreased bMEC CHOL and TG contents.Gas chromatography analysis of fatty acid compositionshowed that the contents of α-linolenic acid, palmiticacid, and cis-8,11,14-eicosatrienoic acid were altereddue to changes in the level of expression of the CD44gene. Additionally, elaidic acid, palmitoleic acid, tridecanoicacid, and oleic acid were markedly reduced inthe CD44 gene overexpression group compared with thecontrol group. On the contrary, cis-5,8,11,14-eicosatetraenoicacid and stearic acid were markedly increasedin the CD44 knockdown group compared with thecontrol group. And RT~2 Profiler PCR array (Qiagen,CLAB24070A Frankfurt, Germany) further suggestedthat overexpression or knockdown of the CD44 genealtered expression levels of functional genes associatedwith lipid metabolism. The present data indicate thatCD44 plays a key regulatory role in lipid metabolismin bMEC.