The Ca2+-calmodulin-Ca2+/calmodulin- dependent protein kinase II signaling pathway is involved in oxidative stress-induced mitochondrial permeability transition and apoptosis in is...

Authors
Toledo, Flavia Daniela; Perez, Leonardo Martin; Basiglio, Cecilia Lorena; Ochoa, Justina Elena; Sanchez Pozzi, Enrique Juan; Roma, Marcelo Gabriel
Publication Year
2014
Language
English
Format
article
Status
Published version
Description
Oxidative stress (OS) is a common event in most hepatopathies, leading to mitochondrial permeability transition pore (MPTP) formation and further exacerbation of both OS from mitochondrial origin and cell death. Intracellular Ca2+ increase plays a permissive role in these events, but the underlying mechanisms are poorly known. We examined in primary cultured rat hepatocytes whether the Ca2+/calmodulin (CaM)-dependent protein kinase II (CaMKII) signaling pathway is involved in this process, by using tert-butyl hydroperoxide (tBOOH) as a pro-oxidant, model compound. tBOOH (500 μM, 15 min) induced MPTP formation, as assessed by measuring mitochondrial membrane depolarization as a surrogate marker, and increased lipid peroxidation in a cyclosporin A (CsA)-sensitive manner, revealing the involvement of MPTPs in tBOOH-induced radical oxygen species (ROS) formation. Intracellular Ca2+ sequestration with BAPTA/AM, CaM blockage with W7 or trifluoperazine, and CaMKII inhibition with KN-62 all fully prevented tBOOH-induced MPTP opening and reduced tBOOH-induced lipid peroxidation to a similar extent to CsA, suggesting that Ca2+/CaM/CaMKII signaling pathway fully mediates MPTP-mediated mitochondrial ROS generation. tBOOH-induced apoptosis, as shown by flow cytometry of annexin V/propidium iodide, mitochondrial release of cytochrome c, activation of caspase-3 and increase in the Bax-to-Bcl-xL ratio, and the Ca2+/CaM/CaMKII signaling antagonists fully prevented these effects. Intramitochondrial CaM and CaMKII were partially involved in tBOOH-induced MPTP formation, since W7 and KN-62 both attenuated the tBOOH-induced, MPTP-mediated swelling of isolated mitochondria. We concluded that Ca2+/CaM/CaMKII signaling pathway is a key mediator of OS-induced MPTP formation and the subsequent exacerbation of OS from mitochondrial origin and apoptotic cell death.
Fil: Toledo, Flavia Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina
Fil: Perez, Leonardo Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina
Fil: Basiglio, Cecilia Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina
Fil: Ochoa, Justina Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina
Fil: Sanchez Pozzi, Enrique Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina
Fil: Roma, Marcelo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Fisiología Experimental (i); Argentina
Subject
OXIDATIVE STRESS
TERT-BUTYL HYDROPEROXIDE
Ca2+/CALMODULIN-DEPENDENT PROTEIN KINASE II
MITOCHONDRIAL PERMEABILITY TRANSITION PORE
APOPTOSIS
CYTOCHROME C
Bioquímica y Biología Molecular
Medicina Básica
CIENCIAS MÉDICAS Y DE LA SALUD
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/6104