Calcium-dependent mitochondrial cAMP production enhances aldosterone secretion

D Katona, A Rajki, G Di Benedetto, T Pozzan… - Molecular and Cellular …, 2015 - Elsevier
D Katona, A Rajki, G Di Benedetto, T Pozzan, A Spät
Molecular and Cellular Endocrinology, 2015Elsevier
Glomerulosa cells secrete aldosterone in response to agonists coupled to Ca 2+ increases
such as angiotensin II and corticotrophin, coupled to a cAMP dependent pathway. A recently
recognized interaction between Ca 2+ and cAMP is the Ca 2+-induced cAMP formation in
the mitochondrial matrix. Here we describe that soluble adenylyl cyclase (sAC) is expressed
in H295R adrenocortical cells. Mitochondrial cAMP formation, monitored with a mitochondria-
targeted fluorescent sensor (4mtH30), is enhanced by HCO 3− and the Ca 2+ mobilizing …
Abstract
Glomerulosa cells secrete aldosterone in response to agonists coupled to Ca2+ increases such as angiotensin II and corticotrophin, coupled to a cAMP dependent pathway. A recently recognized interaction between Ca2+ and cAMP is the Ca2+-induced cAMP formation in the mitochondrial matrix. Here we describe that soluble adenylyl cyclase (sAC) is expressed in H295R adrenocortical cells. Mitochondrial cAMP formation, monitored with a mitochondria-targeted fluorescent sensor (4mtH30), is enhanced by HCO3 and the Ca2+ mobilizing agonist angiotensin II. The effect of angiotensin II is inhibited by 2-OHE, an inhibitor of sAC, and by RNA interference of sAC, but enhanced by an inhibitor of phosphodiesterase PDE2A. Heterologous expression of the Ca2+ binding protein S100G within the mitochondrial matrix attenuates angiotensin II-induced mitochondrial cAMP formation. Inhibition and knockdown of sAC significantly reduce angiotensin II-induced aldosterone production. These data provide the first evidence for a cell-specific functional role of mitochondrial cAMP.
Elsevier