Elevated cAMP Protects against Diclofenac-Induced Toxicity in Primary Rat Hepatocytes: A Protective Effect Mediated by the Exchange Protein Directly Activated by cAMP/cAMP-Regulated Guanine Nucleotide Exchange Factors

Chronic consumption of the nonsteroidal anti-inflammatory drug diclofenac may induce drug-induced liver injury (DILI). The mechanism diclofenac-induced is partially elucidated and involves mitochondrial damage. Elevated cAMP protects hepatocytes against bile acid–induced injury. However, it unknown whether DILI and, if so, which downstream targets are implicated in protective mechanism, including classic protein kinase A (PKA) pathway or alternative pathways like exchange directly activated by (EPAC). aim this study was to investigate and/or its protect hepatocytes. Rat were exposed 400 µmol/l diclofenac. Apoptosis necrosis measured caspase-3 activity assay Sytox green staining, respectively. Mitochondrial membrane potential (MMP) JC-10 staining. mRNA expression assessed quantitative polymerase chain reaction (qPCR) Western blot, cAMP-elevating agent 7β-acetoxy-8,13-epoxy-1α,6β,9α-trihydroxylabd-14-en-11-one (forskolin), pan-phosphodiesterase inhibitor IBMX, EPAC inhibitors 5,7-dibromo-6-fluoro-3,4-dihydro-2-methyl-1(2H)-quinoline carboxaldehyde (CE3F4) ESI-O5 used assess role effectors, PKA EPAC. Diclofenac exposure induced apoptotic cell death loss MMP Both forskolin IBMX prevented apoptosis. inhibition but not abolished effect IBMX. Forskolin preserved MMP, whereas both diminished effect. EPAC1 EPAC2 expressed localized mitochondria. elevation death, a process primarily involving EPACs. cAMP/EPAC be novel target for treatment DILI. SIGNIFICANCE STATEMENT This shows two main highlights. First, elevated levels apoptosis primary via maintenance integrity. In addition, proposes existence cAMP-EPAC microdomains rat hepatocytes, opening new avenues targeted therapy EPAC2, A, responsible Our findings present as dysfunction.