Cytochrome c upregulation during capacitation and spontaneous acrosome reaction determines the fate of pig sperm cells: linking proteome analysis.
To identify the mechanisms underlying capacitation, we undertook a high-resolution differential proteomic analysis of pig sperm cells. Two-dimensional gel electrophoresis and subsequent MALDI-TOF mass spectrometry analyses led to identification of 56 differentially expressed proteins. After induction of capacitation in vitro, the well-established markers of the capacitation (lactadherin P47, acrosomal protein SP-10 precursor, prohibitin, proteasomes, DJ-1 protein and arylsulfatase-A) and TCA cycle proteins (isocitrate dehydrogenase, malate dehydrogenase and pyruvate dehydrogenase) were identified. During induction, cytochrome c expression via the p53 pathway increased, however apoptotic executors, such as caspase-3, decreased significantly. Therefore, we tested the hypothesis that cytochrome c upregulation in spermatozoa is capable of activating tyrosine phosphorylation for capacitation, rather than apoptosis. Exposure of sperm cells to soluble Na2CrO4 [Cr (VI)], which induces cytochrome c upregulation, caused a dose- and time-dependent increase in tyrosine phosphorylation of sperm proteins in non-capacitating medium. In contrast, supplementation of cyclosporin A, which blocks cytochrome c upregulation, inhibited tyrosine phosphorylation of sperm proteins. Furthermore, spermatozoa in capacitation medium or non-capacitation media supplemented with soluble Cr (VI) showed similar levels of capacitation. These findings indicate that differential expression of many of these proteins has previously been unrecognized in sperm cells incubated in capacitation medium also suggest that a gradual increase of cytochrome c during incubation to induce capacitation determines sperm cell fate, i.e., apoptosis or further development for fertilization.
Choi
Yun-Jung
YJ
Department of Animal Biotechnology, College of Animal Bioscience and Technology, Konkuk University, Seoul, Korea.
Uhm
Sang-Jun
SJ
Song
Sang-Jin
SJ
Song
Hyuk
H
Park
Jin-Ki
JK
Kim
Teoan
T
Park
Chankyu
C
Kim
Jin-Hoi
JH
D020101:Acrosome Reaction / Q000502:physiology; D000818:Animals; D003470:Culture Media; D045304:Cytochromes c / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D008297:Male; D010641:Phenotype; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013075:Sperm Capacitation / Q000502:physiology*; D013094:Spermatozoa / Q000378:metabolism* / Q000502:physiology; D013552:Swine; D015854:Up-Regulation
D003470:Culture Media; D045304:Cytochromes c