1alpha,25(OH)2-Vitamin D3 stimulation of secretion via chloride channel activation in Sertoli cells.
Sertoli cell secretory activities are highly dependent on ion channel functions and critical to spermatogenesis. The steroid hormone 1alpha,25(OH)2-vitamin D3 (1,25(OH)2-D3) stimulates exocytosis in different cell systems by activating a nongenotropic vitamin D receptor (VDR). Here, we described 1,25(OH)2-D3 stimulation of secretion via Cl(-) channel activation in the mouse immature Sertoli cell line TM4. 1,25(OH)2-D3 potentiation of chloride currents was dependent on hormone concentration, and correlated with a significant increase in whole-cell capacitance within 20-40 min. In addition, Cl(-) currents were potentiated by the nongenomic VDR agonist 1alpha,25(OH)2 lumisterol D3 (JN), while 1,25(OH)2-D3 potentiation of channels was suppressed by nongenomic VDR antagonist 1beta,25(OH)2-vitamin D3 (HL). Treatment of TM4 cells with PKC and PKA activators PMA and forskolin respectively, increased Cl(-) currents significantly, while PKC and PKA inhibitors Go6983 and H-89, respectively, abolished 1,25(OH)2-D3 stimulation of Cl(-) currents, suggesting phosphorylation pathways in 1,25(OH))2-D3 mediated channel responses. RT-PCR demonstrated the expression of outwardly rectifying ClC-3 channels in TM4 cells. Taken together, our results demonstrate a PKA/PKC-dependent 1,25(OH)2-D3/VDR nongenotropic pathway leading to Cl(-) channel and exocytosis activation in Sertoli cells. We conclude that 1,25(OH)2-D3 appears to be a modulator of male reproductive functions at least in part by stimulating Sertoli cell secretory functions.
Menegaz
Danusa
D
Department of Biochemistry, University of California, 900 University Ave., Riverside, CA 92521, USA.
Barrientos-Duran
Antonio
A
Kline
Andrew
A
Silva
Fatima R M B
FR
Norman
Anthony W
AW
Mizwicki
Mathew T
MT
Zanello
Laura P
LP
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002112:Calcifediol / Q000494:pharmacology; D002117:Calcitriol / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000242:Cyclic AMP / Q000819:agonists; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020536:Enzyme Activators / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects; D015870:Gene Expression; D015640:Ion Channel Gating / Q000187:drug effects; D008297:Male; D051379:Mice; D020033:Protein Isoforms / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D012708:Sertoli Cells / Q000187:drug effects* / Q000378:metabolism* / Q000473:pathology
D018118:Chloride Channels; D020536:Enzyme Activators; D020033:Protein Isoforms; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D000262:Adenylyl Cyclases; D002117:Calcitriol; D002112:Calcifediol