Strains of Caenorhabditis elegans mutant for clk-1 exhibit a 20-40% increase in mean lifespan. clk-1 encodes a mitochondrial protein thought to be either an enzyme or regulatory molecule acting within the ubiquinone biosynthesis pathway. Here CLK-1 is shown to be related to the ubiquinol oxidase, alternative oxidase, and belong to the functionally diverse di-iron-carboxylate protein family which includes bacterioferritin and methane mono-oxygenase.
NaCT (sodium-coupled citrate transporter) is an Na(+)-coupled citrate transporter identified recently in mammals that mediates the cellular uptake of citrate. It is expressed predominantly in the liver. NaCT is structurally and functionally related to the product of the Indy (I'm not dead yet) gene in Drosophila, the dysfunction of which leads to lifespan extension. Here, we show that NaCT mediates the utilization of extracellular citrate for fat synthesis in human liver cells, and that the process is stimulated by lithium.
In lower organisms, increased expression of the NAD-dependent deacetylase Sir2 augments lifespan. The mechanism through which this life extension is mediated remains incompletely understood. Here we have examined the cellular effects of overexpression of SIRT1, the closest mammalian ortholog of Sir2. In PC12 cells, increased expression of the NAD-dependent deacetylase SIRT1 reduces cellular oxygen consumption by approximately 25%. We further demonstrate that SIRT1 expression can alter the transcriptional activity of the mitochondrial biogenesis coactivator PGC-1alpha.
Proceedings of the National Academy of Sciences of the United States of America
In investigating the role of metal ions in the pathogenesis of Huntington's disease, we examined the effects of clioquinol, a metal-binding compound currently in clinical trials for Alzheimer's disease treatment, on mutant huntingtin-expressing cells. We found that PC12 cells expressing polyglutamine-expanded huntingtin exon 1 accumulated less mutant protein and showed decreased cell death when treated with clioquinol. This effect was polyglutamine-length-specific and did not alter mRNA levels or protein degradation rates.
International Journal of Radiation Oncology, Biology, Physics
PURPOSE: We investigated the effects of fractionated radiation treatments on the life spans of athymic rats bearing intracerebral brain tumors. METHODS AND MATERIALS: U-251 MG or U-87 MG human glioblastoma cells were implanted into the brains of athymic rats, and the resulting tumors were irradiated once daily with various doses of ionizing radiation for 5 consecutive days or for 10 days with a 2-day break after Day 5. RESULTS: Five daily doses of 1 and 1.5 Gy, and 10 doses of 0.75 and 1 Gy, cured some U-251 MG tumors.
Recent studies confirm that dietary methionine restriction increases both mean and maximal lifespan in rats and mice, achieving "aging retardant" effects very similar to those of caloric restriction, including a suppression of mitochondrial superoxide generation. Although voluntary caloric restriction is never likely to gain much popularity as a pro-longevity strategy for humans, it may be more feasible to achieve moderate methionine restriction, in light of the fact that vegan diets tend to be relatively low in this amino acid.
Likars'ka Sprava / Ministerstvo Okhorony Zdorov'ia UkraÔny
Telomeres are the ends of chromosomes and are non-coding DNA "end-capped" with structures containing DNA-quadruplexes and proteins. Telomeres become shorter after each cell division, which is one of the mechanisms of gradual ageing. Telomerase is the reverse transcriptase responsible for the extension of telomere length. It is well known that activation of telomerase in the most types of organism's cells is not enough for telomere length stabilization. The reason may be in the telomere "caps", which cover telomere ends from telomerase action.
A botanical extract (Regrapex-R) prepared from whole grape (Vitis vinifera) and Polygonum cuspidatum, which contains polyphenols, including flavans, anthocyanins, emodin, and resveratrol, exhibited dose-dependent scavenging effects on reactive oxygen species (ROS). The extract inhibited increases of ROS and protein carbonyl in isolated rat liver mitochondria following exposure to 2,2'-azobis (2-amidino propane) dihydrocholoride (AAPH), a potent lipid oxidant generator.
Vitamin E refers to a family of several compounds that possess a similar chemical structure comprising a chromanol ring with a 16-carbon side chain. The degree of saturation of the side chain, and positions and nature of methyl groups designate the compounds as tocopherols or tocotrienols. Vitamin E compounds have antioxidant properties due to a hydroxyl group on the chromanol ring. Recently, it has been suggested that vitamin E may also regulate signal transduction and gene expression.
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.