Mitochondrial & redox abnormalities in autism lymphoblastoid cells: A sibling control study

Abstract

Autism spectrum disorder (ASD) is associated with physiological abnormalities, including abnormal redox and mitochondrial metabolism. Lymphoblastoid cell lines (LCLs) from some children with ASD exhibit increased oxidative stress, decreased glutathione redox capacity, and highly active mitochondria with increased vulnerability to reactive oxygen species (ROS). Because unaffected siblings (Sibs) of individuals with ASD share some redox abnormalities, we sought to determine whether LCLs from Sibs share ASD-Associated mitochondrial abnormalities. We evaluated mitochondrial bioenergetics in 10 sets of LCLs from children with ASD, Sibs, and unrelated/unaffected controls (Cons) after acute increases in ROS. Additionally, intracellular glutathione and uncoupling protein 2 (UCP2) gene expressions were quantified. Compared to Sib LCLs, ASD LCLs exhibited significantly higher ATP-linked respiration, higher maximal and reserve respiratory capacity, and greater glycolysis and glycolytic reserve. ASD LCLs exhibited a significantly greater change in theseparameters, with acute increases inROScompared tobothSib andCon LCLs. Compared to Con, both ASD and Sib LCLs exhibited significantly higher proton leak respiration. Consistent with this, intracellular glutathione redox capacitywas decreased andUCP2gene expression was increased in bothASD and Sib compared to Con LCLs. These data indicate that mitochondrial respiratory function, not abnormal redox homeostasis, distinguishes ASD from unaffected LCLs.