Decreased Proteasomal Activity Causes Age-Related Phenotypes and Promotes the Development of Metabolic Abnormalities

作者:Tomaru Utano*; Takahashi Satomi; Ishizu Akihiro; Miyatake Yukiko; Gohda Aya; Suzuki Sayuri; Ono Ayako; Ohara Jiro; Baba Tomohisa; Murata Shigeo; Tanaka Keiji; Kasahara Masanori
来源:American Journal Of Pathology, 2012, 180(3): 963-972.
DOI:10.1016/j.ajpath.2011.11.012

摘要

The proteasome is a multicatalytic enzyme complex responsible for the degradation of both normal and damaged proteins. An age-related decline in proteasomal activity has been implicated in various age-related pathologies. The relevance of decreased proteasomal activity to aging and age-related diseases remains unclear, however, because suitable animal models are not available. In the present study, we established a transgenic (Tg) mouse model with decreased proteasomal chymotrypsin-like activity. Tg mice exhibited a shortened life span and developed age-related phenotypes. In Tg mice, polyubiquitinated and oxidized proteins accumulated, and the expression levels of cellular proteins such as Bcl-xL and RNase L were altered. When Tg mice were fed a high-fat diet, they developed more pronounced obesity and hepatic steatosis than did wild-type mice. Consistent with its role in lipid droplet formation, the expression of adipose differentiation-related protein (ADRP) was elevated in the livers of Tg mice. Of note, obesity and hepatic steatosis induced by a high-fat diet were more pronounced in aged than in young wild-type mice, and aged wild-type mice had elevated levels of ADRP, suggesting that the metabolic abnormalities present in Tg mice mimic those in aged mice. Our results proteasomal chymotrypsin-like activity affects longevity and aggravates age-related metabolic disorders, such as obesity and hepatic steatosis. (Am J Pathol(2012, 180:963-972; DOI. 10.1016/j.ajpath.2011.11.012)