NAMPT (visfatin) in the chicken testis: influence of sexual maturation on cellular localization, plasma levels and gene and protein expression

Abstract

Nicotinamide phosphoribosyltransferase (NAMPT) is a cytokine hormone and rate-limiting enzyme involved in production of NAD and therefore affects a variety of cellular functions requiring NAD. Spermatogenesis and testicular steroidogenesis are likely to depend on NAD-dependent reactions and may therefore be affected by changes in testicular NAMPT expression. The objectives of the present study are to investigate testicular NAMPT expression as well as plasma NAMPT levels in prepubertal and adult chickens. By RT-PCR, NAMPT cDNA expression was detected in prepubertal and adult chicken testes. Using immunohistochemistry, NAMPT was predominantly localized in the nucleus of myoid cells, Sertoli cells, and Leydig cells in the prepubertal chicken testis. In adult chickens, however, NAMPT-immunostaining was observed in the cytoplasm of Leydig cells, Sertoli cells, primary spermatocytes, secondary spermatocytes, round spermatids, and elongated spermatids, but not in the spermatogonial cells. Using real-time quantitative PCR, adult chicken testis was found to contain fourfold greater NAMPT mRNA quantity compared with prepubertal chickens. Testicular NAMPT protein quantities determined by western blotting were not significantly different between adult and prepubertal chicken testes. Using immunoblotting, NAMPT was detected in the seminal plasma and sperm protein extracts obtained from chicken semen. Plasma NAMPT levels, determined by enzyme immunoassay, were at least 28-fold higher in the adult chickens compared with prepubertal male chickens. Taken together, sexual maturation is associated with several changes in testicular NAMPT expression indicating that NAMPT is likely to play a significant role in testicular functions such as spermatogenesis and steroidogenesis.

Analysis of the nicotinamide phosphoribosyltransferase family provides insight into vertebrate adaptation to different oxygen levels during the water‐to‐land transition

“…NAMPTA has been reported in different vertebrate lineages such as fish , birds and mammals , although nothing is known about the presence of NAMPTB. In the present study, the origination, evolution and functions of NAMPTB were analyzed for the first time in vertebrates.…”

Nicotinamide phosphoribosyltransferase production in human spermatozoa is influenced by maturation stage

“…To the best of our knowledge, we report for the first time the presence of NAMPT in human spermatozoa. In this study, the expression pattern of NAMPT was similar to the results found in chicken testis (Ocón‐Grove et al ., ). In detail, NAMPT was detectable in spermatogonia, spermatocytes, Sertoli and Leydig cells.…”

“…NAMPT concentrations in seminal plasma were nearly 100‐fold higher than that measured in serum (Thomas et al ., ). NAMPT protein has been detected in chicken spermatocytes, spermatids and seminal plasma (Ocón‐Grove et al ., ). We hypothesise that NAMPT is also present in human testes and spermatozoa.…”

An NAD+ biosynthetic pathway enzyme functions cell non‐autonomously in C. elegans development

“…Given the role of salvage biosynthesis in the maintenance of NAD + levels and its importance in general metabolism, it came as a surprise that neither expression of Nampt in mice nor nicotinamidases in Drosophila and C. elegans is ubiquitous (Chintapalli et al, 2007; Revollo et al, 2007b; Vrablik et al, 2009). Like C. elegans, which encodes a secreted PNC-1 isoform, vertebrates express an intracellular (iNampt) and extracellular (eNampt) (Yonezawa et al, 2006; Revollo et al, 2007a; Ocón-Grove et al, 2010). NAD + biosynthetic capacity might be provided to tissues that lack Nampt or nicotinamidase expression by cell-autonomous expression of enzymes in other NAD + biosynthetic pathways.…”