Ryanodine receptors are expressed and functionally active in mouse spermatogenic cells and their inhibition interferes with spermatogonial differentiation

Abstract

Ryanodine receptors (RyRs) are intracellular calcium release channels that are highly expressed in striated muscle and neurons but are also detected in several non-excitable cells. We have studied the expression of the three RyR isoforms in male germ cells at different stages of maturation by western blot and RT-PCR. RyR1 was expressed in spermatogonia, pachytene spermatocytes and round spermatids whereas RyR2 was found only in 5- to 10-day-old testis but not in germ cells. RyR3 was not revealed at the protein level, although its mRNA was detected in mixed populations of germ cells. Caffeine, a known agonist of RyRs, was able to induce release of Ca 2+ from intracellular stores in spermatogonia, pachytene spermatocytes and round spermatids, but not spermatozoa. Treatment with high doses of ryanodine, which are known to block RyR channel activity, reduced spermatogonial proliferation and induced meiosis in in vitro organ cultures of testis from 7-day-old mice. In conclusion, the results presented here indicate that RyRs are present in germ cells and that calcium mobilization through RyR channels could participate to the regulation of male germ maturation

Messenger-specific Role for Nicotinic Acid Adenine Dinucleotide Phosphate in Neuronal Differentiation

“…Section 1734 solely to indicate this fact. 1 (43,44), cardiac myocytes (39,45), spermatogenic cells (46), and HL-60 cells (47), the latter via CD-38-mediated production of cADPR, an endogenous modulator of ryanodine receptors (48), direct evidence for inositol trisphosphate receptor involvement is scant. In keratinocytes, phospholipase C-␥1 is necessary for differentiation in response to physiologically relevant elevations in extracellular Ca 2ϩ levels (49).…”

Influence of activator and inhibitors of Ca2+ channels on proliferative activity in Tetrahymena pyriformis infusoria

“…Partic ularly, it was registered that influence of 20 mM caf feine on a primary culture of the prostate stromal cells stimulates proliferation (Wu et al, 2005). A similar effect of caffeine was also detected with respect to nonblast transformed mammalian cells (Chiarella and Puglisi, 2004;Sacks et al, 2008), the Saccharomy ces cerevisiae budding yeasts (Martin et al, 2000;Kim et al, 2008), the Tetrahymena thermophila infusoria (Yakisich et al, 2006), and bacteria (Lawrence et al, 2005). At the same time, there is evidence that inhib iting action of caffeine on the growth of different types of cells (Isfort et al, 1996;Desfrere et al, 2007), including the cells of lower eukaryotes (Yeung et al, 2006), is also possible.…”

In Vitro Effect of Gold or Silver Nanoparticles on Meiotic and Postmeiotic Fractions of Rat Germinal Cells

“…To choose the concentrations used in these experiments, we considered the results obtained by our group in a recent study of the effects of such NPs on ejaculated human sperm [16]; in the present study we were interested in exploring the toxic effects of Au or Ag NPs on testicular germ cells, in particular, their possible ability to penetrate inside the cells, and in defining their localisation. We chose rat germ cells mainly due to the difficulty of working with human germ cells and to take advantage of the existing method for purifying the meiotic and post meiotic fractions from rat testis [17], excluding all other cells. The significant dose dependent cytotoxic effect of both NPs on both fractions of germ cells was demonstrated and the Ag-NPs appeared to be significantly more harmful for meiotic and post meiotic sperm fractions than Au-NPs.…”

“…After removal of the tunica albuginea, testes were placed in culture medium containing collagenase (activity 0.450 unity/ml) and incubated for 10 min to remove the interstitium, which was discarded. A second incubation in a shaking water bath at 32 °C for 45 min with the same enzymes and 0.1% Bovine Serum Albumin and DNAse was performed to partially digest the basal lamina of tubules [17]. The cell suspension obtained after enzymatic digestion was used for NPs treatment.…”