Leptin and leptin receptor in pig spermatozoa: evidence of their involvement in sperm capacitation and survival.
Several studies have recently investigated the role of leptin, the adipocyte-secreted hormone, in the growth and reproduction of rodents, humans, and domestic animals. The present study was designed to explore the expression of leptin and its receptor in pig spermatozoa. Successful Western blot evidenced a 16 kDa band for leptin and six isoforms, ranging from 120 to 40 kDa, for the leptin receptor. Both leptin and leptin receptor were interestingly located at sperm acrosomal level, suggesting their involvement in the oocyte fertilization events. In fact, both capacitation indexes and acrosin activity were enhanced by leptin, and these effects were reduced by the anti-leptin receptor antibody. Afterwards, we investigated the main transduction pathways regulated by the hormone. Our results showed that, in pig sperm, leptin can trigger the signal transducer and activator of transcription 3, a classical component of cytokine signal transduction pathways, whose expression has not been previously reported in male gamete; in addition it was found constitutively activated. Besides, leptin was able to induce the activation of phosphatidylinositol phosphate kinase 3 and MAP kinase pathways as well as of BCL2, a known antiapoptotic protein. These data address to a role of leptin and its receptor on pig sperm survival. The presence of leptin and its receptor in pig sperm suggests that they, through an autocrine short loop, may induce signal transduction and molecular changes associated with sperm capacitation and survival.
Aquila
Saveria
S
Department of Pharmaco-Biology, Faculty of Pharmacy, University of Calabria, 87036 Arcavacata di Rende, Cosenza, Italy.
Rago
Vittoria
V
Guido
Carmela
C
Casaburi
Ivan
I
Zupo
Silvia
S
Carpino
Amalia
A
D000177:Acrosome / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western / Q000379:methods; D002470:Cell Survival; D020738:Leptin / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D008297:Male; D020928:Mitogen-Activated Protein Kinases / Q000032:analysis / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000032:analysis / Q000378:metabolism; D020033:Protein Isoforms / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000032:analysis / Q000378:metabolism; D054411:Receptors, Leptin / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013075:Sperm Capacitation / Q000502:physiology*; D034421:Sus scrofa / Q000502:physiology*; D051025:bcl-Associated Death Protein / Q000032:analysis / Q000378:metabolism
D020738:Leptin; D020033:Protein Isoforms; D054411:Receptors, Leptin; D050796:STAT3 Transcription Factor; D051025:bcl-Associated Death Protein; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases