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Pathophysiological significance of senescence marker protein‐30
Author(s) -
Maruyama Naoki,
Ishigami Akihito,
Kondo Yoshitaka
Publication year - 2010
Publication title -
geriatrics and gerontology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 57
eISSN - 1447-0594
pISSN - 1444-1586
DOI - 10.1111/j.1447-0594.2010.00586.x
Subject(s) - senescence , lipofuscin , ascorbic acid , knockout mouse , biology , endocrinology , medicine , gene , microbiology and biotechnology , biochemistry , food science
A novel rat liver protein of 30 kDa, SMP30 decreases with aging. This protein is expressed most prominently in the liver and kidneys among the various organs. Its gene is located on the X chromosome. No functional domain was recognized in the entire amino acid sequence. Recently, we found a homology between rat SMP30 and two species of bacterial gluconolactonase (EC 3.1.1.17). The lactonase reaction with l ‐gulono‐γ‐lactone is the penultimate step in vitamin C ( l ‐ascorbic acid) biosynthesis. SMP30‐knockout (KO) mice fed a vitamin C‐deficient diet displayed symptoms of scurvy. In SMP30‐KO mice, hepatocytes were more susceptible to apoptosis induced by TNF‐α plus actinomycin D than hepatocytes from wild‐type mice. Two morphological features considered to be a hallmark of senescence are apparent in SMP30‐KO mice. At 12 months of age, SMP30‐knockout mice had clearly visible deposits of lipofuscin and senescence‐associated β‐galactosidase (SA‐β‐GAL) in their renal tubular epithelia. These features are compatible with high electron dense deposits in lysosomes. This observation suggests that the SMP30‐knockout mouse is a useful model of ordinal senescence. Geriatr Gerontol Int 2010; 10 (Suppl. 1): S88–S98.