Mitochondrial bioenergetics and permeability response in rat pulmonary microvascular endothelial cells in culture (1176.1)

Hyperoxia causes lung endothelial injury and depresses mitochondrial complex I (CI) activity. In isolated rat lung perfused with a physiological saline solution (5.5 mM glucose), CI inhibitors decrease lung tissue ATP and increase endothelial permeability (measured as K f ), effects that are overcome using a quinone (CoQ 1 ) (Free Radic Biol Med. doi: 10.1016/j.freeradbiomed.2013.07.040). To unmask the mitochondrial contribution to pulmonary endothelial cell culture permeability responses, PMVEC were treated with the CI inhibitor rotenone (0.5 µM) in 0.2 mM glucose without or with CoQ 1 (10 µM). In PMVEC monolayers, rotenone decreased ATP from 18.4 ± 1.6 (mean ± SE) to 4.6 ± 0.8 nmol/mg protein, decreased O 2 consumption from 2.6 ± 0.1 to 0.3 ± 0.1 nmol/min/mg protein and increased permeability to FITC‐dextran from 8.3 ± 0.7 to 14.3 ± 0.4 nl/min/cm 2 . When CoQ 1 was present with rotenone, ATP (17.4 ± 1.4 nmol/mg protein), O 2 consumption (1.6 ± 0.2 nmol/min/mg protein) and permeability (10.1 ± 1.2 nl /min/cm 2 ) were maintained. CoQ 1 also prevented rotenone‐induced mitochondrial depolarization. Protective effects of CoQ 1 on ATP, O 2 consumption and mitochondrial membrane potential were blocked by inhibitors of the quinone mediated cytosol‐mitochondria electron shuttle. We conclude that, as in the lung, mitochondrial bioenergetics can be a determinant of the PMVEC permeability response. Grant Funding Source : Supported by Dept of Veterans Affairs