Role of estrogen receptors, P450 aromatase, PCNA and p53 in high-fat-induced impairment of spermatogenesis in rats

Abstract

Obesity and overweight are frequently associated with male subfertility. To address new findings on the players involved in the obesity-induced impairment of spermatogenesis, we used a high-fat diet-induced overweight-rat model. Following four weeks of high-fat diet, the organization of seminiferous epithelium was affected, and tubules lumen showed immature/degenerated cells, typical signs of hormonal imbalance and testicular damage. Real-time PCR analysis allowed us to detect increased levels of ERα and decreased levels of aromatase CYP19 transcripts in testis, suggesting an increase in circulating estrogens derived from the accumulating adipose tissue rather than the induction of testicular estrogen synthesis. Moreover, in situ hybridization analysis showed an increased susceptibility towards estrogens in testis from high-fat fed rats, being ERs expressed not only in spermatogonia, as in control testis, but also in spermatids. Western blot and immunohistochemical analyses revealed an increase in the amount of p53 and PCNA, together with a change in their immunodetection, being the proteins localised on germ cells at different stages of maturation. Differences in p53 and PCNA expression may give evidence and be part of a cellular response to stress conditions and damage caused by the excessive intake of saturated fatty acids.

Seasonal expression and cellular distribution of star and steroidogenic enzymes in quail testis

“…In particular, we demonstrated that the germ cells, as well as somatic cells, are positive to antibodies for enzymes involved in the sex hormones production, that is, StAR, 3β-HSD, 17β-HSD, P450 arom, 5α-Red Rosati, Agnese, Abbagnale, et al, 2019). Here in, we have for with what has already been highlighted in other animal models, as bivalvia mollusk , amphibians , reptiles , and mammals (Bilińska, Schmalz-Frączek, Kotula, & Carreau, 2001;Carreau et al, 2011). In particular, in Coturnix testis, as well as showed in Podarcis testis , the steroidogenic process could be quite relevant during the spermiogenesis, that is, in spermatids and testicular spermatozoa.…”

“…In the testis, they are primarily produced in Leydig and Sertoli cells, where they are synthesized from a common precursor, the cholesterol, via a series of enzyme-catalyzed reactions (Miller, 1988). However, in recent years it has been showed that germ cells also produce sex hormones Carreau et al, 2011;Prisco et al, 2017;Rosati, Agnese, Abbagnale, et al, 2019;Rosati, Santillo, et al, 2017). Indeed, more recently, in some seasonal breeding, as the bivalve mollusk…”

“…However, it is generally known that sex steroids play a crucial role in the testis, regulating the reproductive processes throughout either the promotion of spermatogenesis and spermiogenesis (e.g., acrosome biogenesis) or the development/differentiation and the maintenance of secondary sex characteristics in all vertebrates, particularly those with seasonal reproductive cycle (Angelini & Botte, 1992;Carreau, Bouraima-Lelong, & Delalande, 2011;Di Fiore et al, 2005;Saez, 1994).…”

“…In the testis, the sex steroid hormones are primarily produced in specialized cells, the Leydig and Sertoli cells, where they are synthesized from a common precursor, the cholesterol, via a series of enzyme-catalyzed reactions (Miller, 1988). In contrast, the possibility exists that sex hormone synthesis also occurs in germ cells Carreau et al, 2011;Prisco, Agnese, De Marino, Andreuccetti, & Rosati, 2017;Rosati, Santillo, et al, 2017. The steroidogenic pathway begins in mitochondria where cholesterol is converted into pregnenolone by the cytochrome P450 side-chain cleavage enzyme (P450scc); in such event, the Steroidogenic Acute Regulatory (StAR) protein is required to shut cholesterol cross the mitochondrial membrane (Stocco, 2000).…”

“…Then, pregnenolone is metabolized to dehydroepiandrosterone in the smooth endoplasmic reticulum, where its modification into androstenedione is due to 3β-hydroxysteroid dehydrogenase (3β-HSD); later, 17βhydroxysteroid dehydrogenase (17β-HSD) catalyzes the transformation of androstenedione to testosterone (T). Finally, testosterone can be converted both in 17β-estradiol (E2) by cytochrome P450 aromatase (P450 arom) or in 5α-dihydrotestosterone (DHT) by 5α-reductase (5α-Red; Carreau et al, 2011;Miller, 1988Miller, , 2007Moeller & Adamski, 2009;Papadopoulos & Miller, 2012).…”