S Grunewald1, C Kriegel, T Baumann, H-J Glander, U Paasch. 1. Department of Dermatology, Training Center of the European Academy of Andrology, University of Leipzig, Ph.-Rosenthal-Str. 23, 04103 Leipzig, Germany. sonja.grunewald@medizin.uni-leipzig.de
Abstract
BACKGROUND: Capacitation of sperm is a prerequisite for successful fertilization, determined by hyperactivated motility, increased tyrosine phosphorylation (TyrP) and membrane changes. However, the exact molecular mechanism is not fully clarified. The calpain-calmodulin-system is essential for membrane fusion during capacitation. Recently, interactions with caspase (CP) activation, a main feature of apoptotic cells, were postulated. The objective of our study was to examine interactions between apoptosis signalling and the calpain-calmodulin-system during capacitation. METHODS: Semen samples from 20 healthy donors were incubated in human tubal fluid at 37 degrees C, 5% CO(2) for 3 h without additives (control), with 3% BSA (capacitation), 10 microM calpain-inhibitor III, 20 microM CP-1 inhibitor or 20 microM calmodulin-antagonist. Capacitation was monitored by computer assisted sperm motion analyzer, chlortetracycline (CTC)-assay and western blot (TyrP). Activation of caspases and integrity of transmembrane mitochondrial potential (TMP) were evaluated by flow cytometry. RESULTS: Capacitation, as measured by CTC assay, increased TyrP levels and hyperactivation, resulted in inactivation of CP-9, CP-3 and improved integrity of the TMP. Inhibition of calpain and CP-1 during capacitation reduced the capacitation-related parameters, but did not lead to apoptosis. Inhibition of calmodulin resulted in blocking of capacitation and stimulation of apoptosis. CONCLUSION: Interaction of the capacitation and apoptosis signalling systems seems to enable the capacitation process by prevention of apoptosis.
BACKGROUND: Capacitation of sperm is a prerequisite for successful fertilization, determined by hyperactivated motility, increased tyrosine phosphorylation (TyrP) and membrane changes. However, the exact molecular mechanism is not fully clarified. The calpain-calmodulin-system is essential for membrane fusion during capacitation. Recently, interactions with caspase (CP) activation, a main feature of apoptotic cells, were postulated. The objective of our study was to examine interactions between apoptosis signalling and the calpain-calmodulin-system during capacitation. METHODS: Semen samples from 20 healthy donors were incubated in human tubal fluid at 37 degrees C, 5% CO(2) for 3 h without additives (control), with 3% BSA (capacitation), 10 microM calpain-inhibitor III, 20 microM CP-1 inhibitor or 20 microM calmodulin-antagonist. Capacitation was monitored by computer assisted sperm motion analyzer, chlortetracycline (CTC)-assay and western blot (TyrP). Activation of caspases and integrity of transmembrane mitochondrial potential (TMP) were evaluated by flow cytometry. RESULTS: Capacitation, as measured by CTC assay, increased TyrP levels and hyperactivation, resulted in inactivation of CP-9, CP-3 and improved integrity of the TMP. Inhibition of calpain and CP-1 during capacitation reduced the capacitation-related parameters, but did not lead to apoptosis. Inhibition of calmodulin resulted in blocking of capacitation and stimulation of apoptosis. CONCLUSION: Interaction of the capacitation and apoptosis signalling systems seems to enable the capacitation process by prevention of apoptosis.
Authors: M Zarei-Kheirabadi; E Shayegan Nia; M Tavalaee; M R Deemeh; M Arabi; M Forouzanfar; Gh R Javadi; M H Nasr-Esfahani Journal: J Assist Reprod Genet Date: 2011-12-20 Impact factor: 3.412
Authors: Ottó Bencsik; Tamás Papp; Máté Berta; Annamária Zana; Péter Forgó; György Dombi; Maria A Andersson; Mirja Salkinoja-Salonen; Csaba Vágvölgyi; András Szekeres Journal: Toxins (Basel) Date: 2014-09-23 Impact factor: 4.546