RESUMO
The naked mole-rat (NMR; Heterocephalus glaber) exhibits cancer resistance and an exceptionally long lifespan of approximately 30 years, but the mechanism(s) underlying increased longevity in NMRs remains unclear. In the present study, we report unique mechanisms underlying cholesterol metabolism in NMR cells, which may be responsible for their anti-senescent properties. NMR fibroblasts expressed ß-catenin abundantly; this high expression was linked to increased accumulation of cholesterol-enriched lipid droplets. Ablation of ß-catenin or inhibition of cholesterol synthesis abolished lipid droplet formation and induced senescence-like phenotypes accompanied by increased oxidative stress. ß-catenin ablation downregulated apolipoprotein F and the LXR/RXR pathway, which are involved in cholesterol transport and biogenesis. Apolipoprotein F ablation also suppressed lipid droplet accumulation and promoted cellular senescence, indicating that apolipoprotein F mediates ß-catenin signaling in NMR cells. Thus, we suggest that ß-catenin in NMRs functions to offset senescence by regulating cholesterol metabolism, which may contribute to increased longevity in NMRs.
Assuntos
Senescência Celular , Colesterol/metabolismo , Fibroblastos/metabolismo , Ratos-Toupeira/metabolismo , Via de Sinalização Wnt , beta Catenina/metabolismo , Animais , Apolipoproteínas/genética , Apolipoproteínas/metabolismo , Gotículas Lipídicas/metabolismo , Longevidade , Camundongos , Ratos-Toupeira/genética , Células NIH 3T3 , Estresse OxidativoRESUMO
Simple chiral recognition method of 2-alkylalcohols on a silica gel plate was proposed by using the induced circular dichroism (ICD) of J-aggregates of diprotonated tetraphenylporphyrin and magnetic circular dichroism (MCD) spectrometry. To the silica gel on a glass slide including a chiral 2-alkylalcohol and 4 M sulfuric acid, the porphyrin in toluene was added and mixed. Then, the glass slide was used for in situ MCD measurement. The observed ICD spectra could recognize well the chirality of the alcohols and the ICD intensity normalized by the MCD intensity of the J-aggregate correlated linearly to the amount of the chiral alcohols in the silica gel.
