Alpha lipoic acid attenuates microvascular endothelial cell hyperpermeability by inhibiting the intrinsic apoptotic signaling.
BACKGROUND
This study examined whether alpha lipoic acid (ALA), an antioxidant with anti-apoptotic properties, synthesized in mitochondria of endothelial cells, would inhibit intrinsic apoptotic signaling and microvascular endothelial cell hyperpermeability.


METHODS
Rat lung microvascular endothelial cells were transfected with BAK (BH3) peptide (5 microg/mL) or active caspase-3 (5 microg/mL) and were pretreated with ALA (10 and 100 micromol/L). Hyperpermeability was determined using fluorescein isothiocyanate albumin-flux across the cells grown as monolayer. Reactive oxygen species (ROS) formation was determined using 123 dihydrorhodamine and mitochondrial membrane potential using JC-1. Cytochrome c levels and caspase-3 activity were determined using an enzyme-linked immunosorbent assay and a fluorometric assay, respectively.


RESULTS
ALA (100 micromol/L) pretreatment attenuated BAK (BH3)-induced hyperpermeability and ROS formation. ALA restored BAK (BH3)-induced collapse in mitochondrial membrane potential and decreased BAK (BH3)-induced cytochrome c release and caspase-3 activity.


CONCLUSIONS
These findings suggest that ALA attenuates BAK-induced monolayer hyperpermeability through the inhibition of ROS formation and intrinsic apoptotic signaling.
Tharakan
Binu
B
Department of Surgery, Texas A&M University Health Science Center College of Medicine, Scott & White Memorial Hospital, 2401 South 31st St., Temple, TX 76508, USA.
Holder-Haynes
Juliet G
JG
Hunter
Felicia A
FA
Childs
Ed W
EW
D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002199:Capillary Permeability; D053148:Caspase 3 / Q000378:metabolism; D002463:Cell Membrane Permeability / Q000187:drug effects / Q000502:physiology*; D002470:Cell Survival; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism; D004195:Disease Models, Animal; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008168:Lung / Q000166:cytology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects / Q000502:physiology; D011336:Probability; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012680:Sensitivity and Specificity; D015398:Signal Transduction; D008063:Thioctic Acid / Q000378:metabolism* / Q000494:pharmacology
D017382:Reactive Oxygen Species; D008063:Thioctic Acid; D045304:Cytochromes c; D053148:Caspase 3