Vitamin E can promote spermatogenesis by regulating the expression of proteins associated with the plasma membranes and protamine biosynthesis

Abstract

Vitamin E is generally believed to promote the production of ovine sperm mainly through its antioxidant effect. Our previous studies have shown that some non-antioxidant genes may also be key in mediating this process. The objective of this study was to identify key candidate proteins that were differentially expressed in response to a treatment with Vitamin E. Prepubertal ovine testicular cells were isolated and divided into two groups. They were either treated with 800 μM Vitamin E (based on our previous results) or used as a non-treated control. After 24 h, all the cells were harvested for proteomic analysis. We found 115 differentially expressed proteins, 4 of which were up-regulated and 111 were down-regulated. A GO term enrichment analysis identified 127 Biological Process, 63 Cell Component and 26 Molecular Function terms that were enriched. Within those terms, 13, 11 and 26 terms were significantly enriched, respectively. Terms related to membrane and enzyme activity including the inner acrosomal membrane, signal peptidase complex, cysteine-type endopeptidase activity, etc., were also markedly enriched, while none of the KEGG pathways were enriched. We found that many of the differentially expressed proteins, such as CD46 (membrane cofactor protein), FLNA (Filamin A), DYSF (Dysferlin), IFT20 (Intraflagellar transport 20), SPCS1 (Signal peptidase complex subunit 1) and SPCS3 (Signal peptidase complex subunit 3) were related to the acrosomal and plasma membranes. A parallel reaction monitoring (PRM) analysis verified that Vitamin E improved spermatogenesis by regulating the expression of FLNA, SPCS3, YBX3 and RARS, proteins that are associated with the plasma membranes and protamine biosynthesis of the spermatozoa.

Keywords: Plasma membrane; Protamine; Proteome; Sheep; Vitamin E.