Effect of progerin on the accumulation of oxidized proteins in fibroblasts from Hutchinson Gilford progeria patients

The mutation responsible for Hutchinson Gilford Progeria Syndrome (HGPS) causes abnormal nuclear morphology. Previous studies show that free radicals and reactive oxygen species play major roles in the etiology and/or progression of neurodegenerative diseases and aging. This study compares oxidative stress responses between progeric and normal fibroblasts. Our data revealed higher ROS levels in HGPS cells compared to age-matched controls. In response to oxidative challenge, progeric cells showed increased mRNA levels for mitochondrial superoxide dismutase (SOD) and SOD protein content. However, this did not prevent a drop in the ATP content of progeria fibroblasts. Previous studies have shown that declines in human fibroblast ATP levels interfere with programmed cell death and promote necrotic inflammation. Notably, in our investigations the ATP content of progeria fibroblasts was only ∼50% of that found in healthy controls. Furthermore, HGPS fibroblast analysis revealed a decrease in total caspase-like proteasome activity and in the levels of two active proteolytic complex subunits (β5 and β7). A number of studies indicate that the molecular mechanisms causing accelerated aging in progeric patients also occur in healthy cells of older individuals. Thus, the results of this study may also help explain some of the cellular changes that accompany normal aging.