Protein folding in the endoplasmic reticulum (ER) requires a high ratio of oxidized to reduced glutathione (GSSG/rGSH). Since the GSSG/rGSH depends on total glutathione (tGSH = GSSG + rGSH) levels, we hypothesized that limiting GSH biosynthesis will ameliorate protein misfolding by enhancing the ER oxidative milieu. As a proof-of-concept, we used DL-buthionine-(S,R)-sulfoximine (BSO) to inhibit GSH biosynthesis in Akita mice, which are prone to proinsulin misfolding.
View Article and Find Full Text PDFDecreasing the dietary intake of methionine exerts robust anti-adiposity effects in rodents but modest effects in humans. Since cysteine can be synthesized from methionine, animal diets are formulated by decreasing methionine and eliminating cysteine. Such diets exert both methionine restriction (MR) and cysteine restriction (CR), that is, sulfur amino acid restriction (SAAR).
View Article and Find Full Text PDFTrade-offs in life-history traits are clinically and mechanistically important. Sulfur amino acid restriction (SAAR) extends lifespan. But whether this benefit comes at the cost of other traits including stress resistance and growth is unclear.
View Article and Find Full Text PDFDietary methionine restriction (MR) has been found to enhance longevity across many species. We hypothesized that MR might enhance longevity in part by delaying or inhibiting age-related disease processes. To this end, male Fischer 344 rats were fed control (CF, 0.
View Article and Find Full Text PDFThe mechanisms underlying life span extension by sulfur amino acid restriction (SAAR) are unclear. Cysteine and methionine are essential for the biosynthesis of proteins and glutathione (GSH), a major redox buffer in the endoplasmic reticulum (ER). We hypothesized that SAAR alters protein synthesis by modulating the redox milieu.
View Article and Find Full Text PDFObjective: This study investigated the effects of dietary methionine restriction (MR) on the progression of established hepatic steatosis in the leptin-deficient ob/ob mouse.
Material/methods: Ten-week-old ob/ob mice were fed diets containing 0.86% (control-fed; CF) or 0.
Restriction of dietary methionine by 80% slows the progression of aged-related diseases and prolongs lifespan in rodents. A salient feature of the methionine restriction phenotype is the significant reduction of adipose tissue mass, which is associated with improvement of insulin sensitivity. These beneficial effects of MR involve a host of metabolic adaptations leading to increased mitochondrial biogenesis and function, elevated energy expenditure, changes of lipid and carbohydrate homeostasis, and decreased oxidative damage and inflammation.
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
September 2010
Dietary methionine restriction (MR) is a mimetic of chronic dietary restriction (DR) in the sense that MR increases rodent longevity, but without food restriction. We report here that MR also persistently increases total energy expenditure (EE) and limits fat deposition despite increasing weight-specific food consumption. In Fischer 344 (F344) rats consuming control or MR diets for 3, 9, and 20 mo, mean EE was 1.
View Article and Find Full Text PDFSustained caloric restriction (CR) extends lifespan in animal models but the mechanism and primary tissue target(s) have not been identified. Gene expression changes with aging and CR were examined in both heart and white adipose tissue (WAT) of Fischer 344 (F344) male rats using Affymetrix RAE 230 arrays and validated by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) on 18 genes. As expected, age had a substantial effect on transcription on both tissues, although only 21% of cardiac age-associated genes were also altered in WAT.
View Article and Find Full Text PDFReduced dietary methionine intake (0.17% methionine, MR) and calorie restriction (CR) prolong lifespan in male Fischer 344 rats. Although the mechanisms are unclear, both regimens feature lower body weight and reductions in adiposity.
View Article and Find Full Text PDFHuman hair follicles were grafted onto 2 strains of immunodeficient mice to compare the regeneration potential of vellus (miniaturized, balding) and terminal (hairy, nonbalding) follicles from males and a female exhibiting pattern baldness. Each mouse had transplants of both types of follicles from a single donor for direct comparison. Grafted follicles from 2 male donors resulted in nonsignificant differences in mean length (52 mm vs 54 mm) and mean diameter (99 microm vs 93 microm) at 22 weeks for hairs originating from balding and hairy scalp, respectively, corresponding to 400% versus 62% of the mean pretransplantation diameters.
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