Rapid effects of aldosterone in primary cultures of cardiomyocytes - do they suggest the existence of a membrane-bound receptor?
Aldosterone acts on its target tissue through a classical mechanism or through the rapid pathway through a putative membrane-bound receptor. Our goal here was to better understand the molecular and biochemical rapid mechanisms responsible for aldosterone-induced cardiomyocyte hypertrophy. We have evaluated the hypertrophic process through the levels of ANP, which was confirmed by the analysis of the superficial area of cardiomyocytes. Aldosterone increased the levels of ANP and the cellular area of the cardiomyocytes; spironolactone reduced the aldosterone-increased ANP level and cellular area of cardiomyocytes. Aldosterone or spironolactone alone did not increase the level of cyclic 3',5'-adenosine monophosphate (cAMP), but aldosterone plus spironolactone led to increased cAMP level; the treatment with aldosterone + spironolactone + BAPTA-AM reduced the levels of cAMP. These data suggest that aldosterone-induced cAMP increase is independent of mineralocorticoid receptor (MR) and dependent on Ca(2+). Next, we have evaluated the role of A-kinase anchor proteins (AKAP) in the aldosterone-induced hypertrophic response. We have found that St-Ht31 (AKAP inhibitor) reduced the increased level of ANP which was induced by aldosterone; in addition, we have found an increase on protein kinase C (PKC) and extracellular signal-regulated kinase 5 (ERK5) activity when cells were treated with aldosterone alone, spironolactone alone and with a combination of both. Our data suggest that PKC could be responsible for ERK5 aldosterone-induced phosphorylation. Our study suggests that the aldosterone through its rapid effects promotes a hypertrophic response in cardiomyocytes that is controlled by an AKAP, being dependent on ERK5 and PKC, but not on cAMP/cAMP-dependent protein kinase signaling pathways. Lastly, we provide evidence that the targeting of AKAPs could be relevant in patients with aldosterone-induced cardiac hypertrophy and heart failure.
a Laboratory of Hypertension , Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil .
Carolina Morais
CM
Araujo
a Laboratory of Hypertension , Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil .
Milla Marques
MM
Hermidorff
a Laboratory of Hypertension , Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil .
Gabriela de Cassia Sousa
Gde C
Amancio
b Laboratory of Immunoparasitology , Center for Research in Biological Sciences, Institute of Biological and Exact Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil .
Denise da Silveira
Dda S
Lemos
c Laboratory of Experimental Nutrition , School of Nutrition, Federal University of Ouro Preto , Ouro Preto , Brazil , and.
Marcelo Estáquio
ME
Silva
d Department of Physiology , Institute of Bioscience, University of São Paulo , São Paulo , Brazil.
Leonardo Vinícius Monteiro
LV
de Assis
a Laboratory of Hypertension , Research Center in Biological Science, Institute of Exact and Biological Sciences, Federal University of Ouro Preto , Ouro Preto , Brazil .
Mauro César
MC
Isoldi
D054758:A Kinase Anchor Proteins / Q000235:genetics / Q000378:metabolism*; D000450:Aldosterone / Q000008:administration & dosage*; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000096:biosynthesis / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004533:Egtazic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives; D006333:Heart Failure / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D006984:Hypertrophy / Q000188:drug therapy* / Q000378:metabolism; D048054:Mitogen-Activated Protein Kinase 7 / Q000096:biosynthesis; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D010766:Phosphorylation; D061251:Primary Cell Culture; D011493:Protein Kinase C / Q000096:biosynthesis; D051381:Rats; D018161:Receptors, Mineralocorticoid / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D013148:Spironolactone / Q000008:administration & dosage
D054758:A Kinase Anchor Proteins; D018161:Receptors, Mineralocorticoid; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D013148:Spironolactone; D000450:Aldosterone; D004533:Egtazic Acid; D009320:Atrial Natriuretic Factor; D000242:Cyclic AMP; D011493:Protein Kinase C; D048054:Mitogen-Activated Protein Kinase 7
Aldosterone; cardiomyocytes; hypertrophy; mineralocorticoid receptor; rapid effects; spironolactone