Stattic V, a STAT3 inhibitor, affects human spermatozoa through regulation of mitochondrial activity.
We have recently shown that many mediators of the JAK/STAT signaling pathway are present in ejaculated human spermatozoa. Among them, STAT3 is detected mainly in membranes and flagellar cytoskeletal fractions. In order to determine the importance of STAT3-mediated signaling, sperm were incubated with Stattic V, a specific inhibitor. Effects on motility were evaluated by CASA, sperm acrosomal integrity was evaluated by FITC conjugated lectin (PSA or PNA) staining, and protein phosphotyrosine content was assessed by Western blot using a monoclonal anti-phosphotyrosine antibody. INDO1-AM and JC-1 were used to measure sperm intracellular calcium and mitochondrial membrane potential, respectively, by flow cytometry, and reactive oxygen species (ROS) production was investigated by luminol-based assay. Percentages of motility and motility parameters were significantly affected by Stattic V. This later also significantly increased intracellular Ca(2+) levels, progesterone- and calcium ionophore (A23187)-induced acrosome reaction. On the other hand, a significant decrease in ATP content was measured when sperm were treated with Stattic V, associated with depolarization of mitochondrial membrane and elevated ROS production. These results suggest that STAT3 is involved in sperm functions, at least through regulation of mitochondrial activity. This further emphasizes that STAT3 mediates cellular activities in a manner different than strictly the activation of gene transcription.
Département d'Obstétrique et de Gynécologie, Centre de recherche en biologie de la reproduction, Université Laval, Axe reproduction, santé périnatale et santé de l'enfant, Centre de recherche du CHUQ-CHUL, Québec, Canada.
Catherine
C
Lachance
Serge
S
Goupil
Pierre
P
Leclerc
D020101:Acrosome Reaction / Q000187:drug effects; D000255:Adenosine Triphosphate / Q000378:metabolism; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D003499:Cyclic S-Oxides / Q000494:pharmacology*; D006801:Humans; D007476:Ionophores / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D019000:Phosphotyrosine / Q000378:metabolism; D011374:Progesterone / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors*; D013081:Sperm Motility / Q000187:drug effects*; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D003499:Cyclic S-Oxides; D007476:Ionophores; D017382:Reactive Oxygen Species; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C517409:stattic; D019000:Phosphotyrosine; D000001:Calcimycin; D011374:Progesterone; D000255:Adenosine Triphosphate; D048051:p38 Mitogen-Activated Protein Kinases; D002118:Calcium