INVESTIGADORES
CASTILLA LOZANO Maria Del Rocio
artículos
Título:
Silencing the expression of mitochondrial acyl-CoA thioesterase I and acyl-CoA synthetase 4 inhibits hormone-induced steroidogenesis.
Autor/es:
MALOBERTI, PAULA-CASTILLA ROCÍO; CASTILLO, FERNANDA; CORNEJO MACIEL, FABIANA; MENDEZ, CARLOS F.; PAZ, CRISTINA; PODESTÁ, ERNESTO J.
Revista:
The FEBS journal
Editorial:
Published by Blackwell Pub. on behalf of the Federation of European Biochemical Societies
Referencias:
Lugar: Inglaterra; Año: 2005 vol. 272 p. 1804 - 1814
ISSN:
1742-464X
Resumen:
Arachidonic acid and its lypoxygenated metabolites play a fundamental role in the hormonal regulation of steroidogenesis. Reduction in the expression of the mitochondrial acyl-CoA thioesterase (MTE-I) by antisense or small interfering RNA (siRNA) and of the arachidonic acid-preferring acyl-CoA synthetase (ACS4) by siRNA produced a marked reduction in steroid output of cAMP-stimulated Leydig cells. This effect was blunted by a permeable analog of cholesterol that bypasses the rate-limiting step in steroidogenesis, the transport of cholesterol from the outer to the inner mitochondrial membrane. The inhibition of steroidogenesis was overcome by addition of exogenous arachidonic acid, indicating that the enzymes are part of the mechanism responsible for arachidonic acid release involved in steroidogenesis. Knocking down the expression of MTE-I leads to a significant reduction in the expression of steroidogenic acute regulatory protein. This protein is induced by arachidonic acid and controls the rate-limiting step. Overexpression of MTE-I resulted in an increase in cAMP-induced steroidogenesis. In summary, our results demonstrate a critical role for ACS4 and MTE-I in the hormonal regulation of steroidogenesis as a new pathway of arachidonic acid release different from the classical phospholipase A2 cascade.