Expression of Type-1 Cannabinoid Receptor During Rat Postnatal Testicular Development: Possible Involvement in Adult Leydig Cell Differentiation1

Abstract

Endocannabinoids are lipidic modulators able to bind cannabinoid receptors (CNRs). Two types of CNRs have been cloned, CNR1 (central) and CNR2 (peripheral). The objectives of the present study were to investigate the expression pattern of CNR1 in the rat testis during prepubertal development and to define the CNR1 spatiotemporal pattern. From 31 to 60 days of age, CNR1 was immunolocalized in round elongating spermatids and spermatozoa, suggesting an important role for this receptor in spermatogenesis. From 14 to 60 days of age, adult Leydig cells (ALCs) at different developmental stages were positive for CNR1. In particular, CNR1 expression in differentiating ALCs was negatively correlated to cell division. Bromodeoxyuridine uptake experiments on serial sections showed that immature Leydig cells in mitosis were negative for CNR1; in contrast, immature nonmitotic Leydig cells were positive for CNR1. A further observation of few ALCs in CNR1KO mice validates the role of CNR1 during proliferative activity involved in ALC differentiation. In addition, starting from 41 days of age, a faint CNR1 signal was also observed in Sertoli cells. Taken together, these results demonstrate the first clear evidence (to our knowledge) of CNR1 in mammalian germinal epithelium, ALCs, and Sertoli cells and indicate that differentiation of ALCs may depend on the endocannabinoid system.

Low 17beta-Estradiol Levels in Cnr1 Knock-Out Mice Affect Spermatid Chromatin Remodeling by Interfering with Chromatin Reorganization

“…At the testicular level, endocannabinoids affect both spermatogenesis and steroidogenesis. In rodents, they regulate immature Sertoli cell activity [28], promote meiosis (i.e., spermatogonia-to-spermatocyte progression) [23], support adult Leydig cell development [29] and function [30] as well as SPT differentiation [14,22,31]. Indeed, in the absence of CNR1 activity, inadequate chromatin remodeling of SPT occurs.…”

Testosterone deficiency accompanied by testicular and epididymal abnormalities in TMF−/− mice

“…2A-C). To test whether the increase in interstitial tissue was due to proliferation of Leydig cells, testes sections were costained with anti-HSD3B to identify Leydig cells (Cacciola et al, 2008) and with anti-PCNA antibodies to detect this DNA replication promoting factor in the nucleus of proliferating Leydig cells (Dietrich, 1993;Sriraman et al, 2000). While proliferating spermatogonia were detected in the basal layers of seminiferous tubules of both wt and TMF À/À mice, testicular TMF À/À sections exhibited frequent PCNA positive staining in Leydig cells, as well.…”

“…Testicular sections from four 40 week-old wt mice (eight sections total) and from four TMF À/À mice of the same age (eight sections total) were stained with anti-PCNA (sc-7907, Santa Cruz, USA-1:100) for immunohistochemical analysis, or co-stained with mouse anti-PCNA (ab-29, Abcam, UK-1:100) and rabbit anti-HSD3B (ab-65156, Abcam, UK-1:100) (a Leydig cell marker) (Cacciola et al, 2008), for immunofluorescence analysis. For quantification of PCNA positively stained Leydig cells, both testes from each one of four 40 week-old wt animals and four TMF À/À agematched mice (16 sections in total, eight of each genotype) were evaluated.…”

Endocannabinoids and Kisspeptins: Two Modulators in Fight for the Regulation of GnRH Activity

“…In males, ECS modulates the progression of spermatogenesis, spermatozoa functions and the activity of testicular somatic cells in mammalian, non-mammalian vertebrates as well as in invertebrates. (Battista et al, 2012;Cacciola et al 2008;Cobellis et al, 2006;Cottone et al, 2008;Grimaldi et al, 2009;Maccarrone et al, 2003Maccarrone et al, , 2005Pierantoni et al, 2009, Schuel et al, 1991Wang et al, 2006). In females, ECBs represent fertility signals in folliculogenesis, follicle maturation, oocyte maturation and ovulation (El-Talatini et al, 2009).…”