Isoforms of angiotensin I-converting enzyme in the development and differentiation of human testis and epididymis

Abstract

Angiotensin I-converting enzyme (ACE; CD143, Kininase II, EC 3.4.15.1) is known to be crucial for male fertility in animal models. We therefore studied its testicular (tACE) and somatic (sACE) isoforms in foetal and adult human testis and epididymis using monoclonal antibodies and cRNA probes. During spermatogenesis, tACE was found only in differentiating germ cells and was the only isoform within the seminiferous tubules of adult men. Although tACE mRNA was present in spermatocytes, tACE protein was initially found in post-meiotic step 3 spermatids and increased markedly during further differentiation. The enzyme was strictly confined to the adluminal membrane site of elongating spermatids and was localized at the neck and midpiece region of released and ejaculated spermatozoa. In contrast, sACE was expressed heterogeneously in Leydig cells and endothelial cells of the testicular interstitium, and homogeneously along the luminal surface of epithelial cells lining the ductuli efferents, corpus and cauda of epididymis, and vas deferens. The cell- and site-restricted pattern of sACE corresponded to that found in foetal tissues except an additional and transient expression of sACE in foetal germ cells and foetal Sertoli cells. Our study documents for the first time in humans the regulation and unique cellular distribution of ACE isoforms during the ontogenesis of the lower male genital tract.

Inflammatory cells in the formation of tumor-related sarcoid reactions

“…In this study, we show that ACE is clearly present in the ECGs of sarcoid reactions and labels specifically epithelioid cells. Several other cell types such as myofibroblasts and some endothelial, epithelial, neuronal, and germ cells are known to express ACE, but their tissue expression is restricted and depends on site, activation, or differentiation [43][44][45][46][47]. Concerning the cell lineages of macrophages, only alveolar macrophages, Gaucher cells, and fat-laden foamy cells in atherosclerosis are furthermore known to express ACE [38,[48][49][50].…”

Surfing the wave, cycle, life history, and genes/proteins expressed by testicular germ cells. Part 3: Developmental changes in spermatid flagellum and cytoplasmic droplet and interaction of sperm with the zona pellucida and egg plasma membrane

“…Ace-deficient mice show greatly reduced fertility, but the testis and sperm production are normal (Krege et al, 1995). In the human testis, the testicular form of ACE is present in differentiating germ cells; mRNA is found in spermatocytes while the protein increases in levels in spermatids during spermiogenesis where it is seen on their plasma membrane (Pauls et al, 2003). ACE has glycosylphosphatidylinositol (GPI)-anchored protein-releasing activity.…”

Expression of testicular angiotensin-converting enzyme in adult spontaneously hypertensive rats.

“…The differences between our data and those by both author groups could be explained by using different antibodies against the portion common to the testicular and somatic ACE isoforms. Species-specific expression of tACE was demonstrated in human testis where reaction was found only in adluminal membranes of postmeiotic germ cells later than step 3 round spermatids [20] corresponding to step 7 round spermatids in rat.…”