Biomedical subjects

Simonetta Petrungaro

Publications and source records attributed to Simonetta Petrungaro.

4 recordsLinked to original sources

PubMed2006

c-Flip(L) is expressed in undifferentiated mouse male germ cells.

Apoptosis represents a fundamental process during fetal/post-natal testis development. Therefore pro- and anti-apoptotic proteins are essential to regulate testis physiology. c-Flip(L) is a known inhibitor of caspase 8/10 activity; in this study its perinatal expression in mouse male germ cells was investigated. In testis sections and seminiferous tubule whole mount c-Flip(L) was found to be expressed in undifferentiated spermatogonia and to co-localize with germ stem cells markers. In vivo investigations in the vitamin-A deficient mouse, lacking differentiated germ cells, confirmed c-Flip(L) expression in undifferentiated spermatogonia. Further analyses showed Fas expression but no significant caspase 8/10 activity when c-Flip(L) was highly expressed. Altogether these data suggest that c-Flip may control the survival rate of undifferentiated spermatogonia.

Animals↗

PubMed2005

c-Flip expression and function in fetal mouse gonocytes.

Apoptosis is a key mechanism in spermatogenesis, and in testis, most gonocytes degenerate at fetal and postnatal ages to select a cell subset committed to become germ stem cells. The aim of the present study is to investigate mechanisms controlling the massive apoptosis of fetal gonocytes. We evaluated the expression and function of c-Flip, an apoptosis inhibitor known to interfere with the proapoptotic Fas-signaling pathway in a variety of cell types, but never investigated in fetal testis. Expression of c-Flip long isoform (c-FlipL) within fetal testis was localized in gonocytes at 16.5 and 18.5 days post coitum (dpc), both at the mRNA and protein level, while it was weakly expressed or undetectable at earlier stages. Moreover, Fas protein was found in fetal testes at 13.5, 16.5, and 18.5 dpc. Testes at 18.5 dpc, expressing high levels of c-FlipL, were resistant to Fas-induced apoptosis while they became highly sensitive when c-FlipL was inhibited by antisense c-Flip oligos. In addition, there was an inverse relation between gonocyte spontaneous apoptosis sensitivity and c-FlipL levels. Furthermore, caspase-10 activity was inversely related with c-FlipL expression, suggesting that caspase-10 might be a target of c-FlipL. These data represent the first evidence demonstrating c-Flip expression in fetal testes and its role in protecting gonocytes from Fas-dependent apoptosis.

Animals↗

PubMed2005

Germ cell apoptosis control during spermatogenesis.

The aim of the present study was to investigate the expression and role of c-Flip long isoform (c-FlipL), a known anti-apoptotic protein. No data are currently available on c-FlipL in male gonad before puberty; therefore, this study was carried out in prepuberal mouse testis. We investigated pachytene spermatocytes and spermatogonia by immunostaining of testis sections and found a strong and specific expression of c-FlipL in pachytene spermatocytes, while spermatogonia expressed very low levels of c-FlipL. This finding inversely correlated with the caspases activity, which was higher in spermatogonia as compared to pachytene spermatocytes. Other experiments carried out in an organ-culture model revealed that Fas-induced apoptosis was higher in spermatogonia as compared to pachytene spermatocytes. These data suggest that c-FlipL may play a role as an anti-apoptotic molecule in the prepuberal mouse testis and open new perspectives in the comprehension of the mechanisms controlling germ cells apoptosis.

Aging↗

PubMed2004

Characterization of signaling pathways leading to Fas expression induced by TNF-alpha: pivotal role of NF-kappaB.

TNF-alpha is known to induce a strong up-regulation of Fas expression in mouse Sertoli cell cultures, leading to their apoptosis triggered by effector FasL-bearing cells. These data suggest that increased Fas expression on the cell surface might be a key event in the pathogenesis of autoimmune orchitis, by inducing a leakage of the blood-tubular barrier as a consequence of Sertoli cell apoptosis. In the present paper, we have investigated the signal transduction mechanisms involved in the regulation of Fas expression induced by TNF-alpha in mouse Sertoli cells. We studied the role of the transcription factor NF-kappaB and of MAPKs in regulating Fas expression. By using Sertoli cells transfected with a NF-kappaB Luc reporter gene, we proved that TNF-alpha activates the IkappaB/NF-kappaB system. Moreover, the use of the proteasome inhibitor lactacystin led us to demonstrate that NF-kappaB is required for TNF-alpha mediated Fas expression. By using specific inhibitors for each MAPK, we confirmed the pivotal role of the IkappaB/NF-kappaB system by demonstrating that ERKs, p38, and JNK are not involved in Fas up-regulation by TNF-alpha. The comprehension of these pathways could be relevant to the knowledge of the pathogenesis of autoimmune disorders in immune privileged districts of the body.

Acetylcysteine↗