title: Depolarization of mitochondrial membrane potential is the initial event in non-nucleoside reverse transcriptase inhibitor efavirenz induced cytotoxicity.
abstract: Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) and an active constituent of the highly active antiretroviral therapy regime. It has significantly contributed in control and management of human immunodeficiency virus propagation. However, EFV administration has also led to severe adverse effects, several reports highlighted the role of EFV in mitochondrial dysfunction and toxicity but the molecular mechanism has been poorly understood. In present study, human hepatoma cells Huh 7.5 were treated with clinically relevant concentrations of EFV and parameters like cytotoxicity, mitochondrial transmembrane potential, mitochondrial morphology, cytochrome c release, mitochondria-mediated apoptosis, mtDNA and mtRNA levels and EFV distribution into mitochondrial compartment were evaluated to understand sequence of events leading to cell death in EFV-treated cells. EFV at its clinically relevant concentration was significantly toxic after 48 and 72 h of treatments. EFV-mediated toxicity is initiated with the permeabilization of mitochondrial outer membrane and change in mitochondrial membrane potential (Δψm) which triggers a series of events like cytochrome c release, alteration in mitochondrial morphology and mitochondria-mediated apoptosis. Total mitochondrial content is reduced after 48 h of EFV treatment at IC50concentration which is also reflected in reduced mitochondrial DNA and RNA levels. After detecting EFV in mitochondrial compartment after 12 h of incubation with EFV, we hypothesize that EFV being a lipophilic molecule is internalized into the mitochondrial compartment causing depolarization of Δψm which subsequently leads to a cascade of events causing cell death.
authors.affiliation: Functional Genomics Lab., Centre for Advanced Study, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India.
authors.forename: Krishna Kumar
authors.initials: KK
authors.lastname: Ganta
authors.affiliation: Functional Genomics Lab., Centre for Advanced Study, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India.
authors.forename: Anirban
authors.initials: A
authors.lastname: Mandal
authors.affiliation: Functional Genomics Lab., Centre for Advanced Study, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, India. bchaubey@hotmail.com.|Department of Recombinant Vaccines, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Kladki 24, 80-822, Gdansk, Poland. bchaubey@hotmail.com.
authors.forename: Binay
authors.initials: B
authors.lastname: Chaubey
mesh_terms: D000480:Alkynes; D017209:Apoptosis / Q000187:drug effects; D048588:Benzoxazines / Q000633:toxicity*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D003521:Cyclopropanes; D045304:Cytochromes c / Q000378:metabolism; D004272:DNA, Mitochondrial / Q000378:metabolism; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D018894:Reverse Transcriptase Inhibitors / Q000633:toxicity*
chemical_list: D000480:Alkynes; D048588:Benzoxazines; D003521:Cyclopropanes; D004272:DNA, Mitochondrial; D018894:Reverse Transcriptase Inhibitors; D012313:RNA; D045304:Cytochromes c; D011065:Poly(ADP-ribose) Polymerases; C098320:efavirenz
keywords: Apoptosis; Cytotoxicity; Efavirenz; Mitochondrial membrane potential