Ogando, D.G.; Kim, E.T.; Li, S.; Bonanno, J.A. Corneal Edema in Inducible Slc4a11 Knockout Is Initiated by Mitochondrial Superoxide Induced Src Kinase Activation. Cells2023, 12, 1528.
Ogando, D.G.; Kim, E.T.; Li, S.; Bonanno, J.A. Corneal Edema in Inducible Slc4a11 Knockout Is Initiated by Mitochondrial Superoxide Induced Src Kinase Activation. Cells 2023, 12, 1528.
Ogando, D.G.; Kim, E.T.; Li, S.; Bonanno, J.A. Corneal Edema in Inducible Slc4a11 Knockout Is Initiated by Mitochondrial Superoxide Induced Src Kinase Activation. Cells2023, 12, 1528.
Ogando, D.G.; Kim, E.T.; Li, S.; Bonanno, J.A. Corneal Edema in Inducible Slc4a11 Knockout Is Initiated by Mitochondrial Superoxide Induced Src Kinase Activation. Cells 2023, 12, 1528.
Abstract
Purpose: Inducible Slc4a11 KO leads to corneal edema by disruption of the pump and barrier functions of the corneal endothelium (CE). The loss of Slc4a11 NH3-activated mitochondrial uncoupling leads to mitochondrial membrane potential hyperpolarization-induced oxidative stress. The goal of this study is to investigate the link between oxidative stress and failure of pump and barrier functions and test different approaches to revert the process. Methods: Mice homozygous for Slc4a11 Flox and Estrogen receptor –Cre Recombinase fusion protein alleles at 8 weeks of age were fed Tamoxifen (Tm) enriched chow (0.4 g/Kg) for 2 weeks, and controls were fed normal chow. During the initial 14 days, Slc4a11 expression, corneal thickness (CT), stromal [lactate], Na+-K+ ATPase activity, mitochondrial superoxide levels, expression of lactate transporters, and activity of key kinases were assessed. In addition, barrier function was assessed by fluorescein permeability, ZO-1 tight junction integrity, and cortical cytoskeleton F-actin morphology. Results: Tm induced a rapid decay in Slc4a11 expression that was 84% complete at 7 days and 96% at 14 days of treatment. Superoxide levels increased significantly by day 7; CT and fluorescein permeability by day 14. Tight junction ZO-1 distribution and cortical cytoskeleton were disrupted at day 14 concomitant with decreased expression of Cldn1 yet an increase in tyrosine phosphorylation. Stromal lactate increased by 60%, Na+-K+ATPase activity decreased by 40%, and expression of lactate transporters MCT2 and MCT4 significantly decreased, but MCT1 was unchanged at 14 days. Src kinase was activated but not Rock, PKCα, JNK, or P38Mapk. Mitochondrial antioxidant Visomitin (SkQ1, mitochondrial targeted antioxidant) or Src kinase inhibitor eCF506 significantly slowed the increase in CT, with concomitant decreased stromal lactate retention, improved barrier function, reduced Src activation and Cldn1 phosphorylation, and rescued MCT2 and MCT4 expression. Conclusions: Slc4a11 KO-induced CE oxidative stress triggered increased Src kinase activity that results in perturbation of pump components and barrier function of the CE.
Biology and Life Sciences, Cell and Developmental Biology
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