SMP30-mediated synthesis of vitamin C activates the liver PPARα/FGF21 axis to regulate thermogenesis in mice.

The vitamin-C-synthesizing enzyme senescent marker protein 30 (SMP30) is a cold resistance gene in Drosophila, and vitamin C concentration increases in brown adipose tissue post-cold exposure. However, the roles of SMP30 in thermogenesis are unknown. Here, we tested the molecular mechanism of thermogenesis using wild-type (WT) and vitamin C-deficient SMP30-knockout (KO) mice. SMP30-KO mice gained more weight than WT mice without a change in food intake in response to short-term high-fat diet feeding. Indirect calorimetry and cold-challenge experiments indicated that energy expenditure is lower in SMP30-KO mice, which is associated with decreased thermogenesis in adipose tissues. Therefore, SMP30-KO mice do not lose weight during cold exposure, whereas WT mice lose weight markedly. Mechanistically, the levels of serum FGF21 were notably lower in SMP30-KO mice, and vitamin C supplementation in SMP30-KO mice recovered FGF21 expression and thermogenesis, with a marked reduction in body weight during cold exposure. Further experiments revealed that vitamin C activates PPARα to upregulate FGF21. Our findings demonstrate that SMP30-mediated synthesis of vitamin C activates the PPARα/FGF21 axis, contributing to the maintenance of thermogenesis in mice.

Beneficial effects of a Q-ter based nutritional mixture on functional performance, mitochondrial function, and oxidative stress in rats.

BACKGROUND: Mitochondrial dysfunction and oxidative stress are central mechanisms underlying the aging process and the pathogenesis of many age-related diseases. Selected antioxidants and specific combinations of nutritional compounds could target many biochemical pathways that affect both oxidative stress and mitochondrial function and, thereby, preserve or enhance physical performance. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we evaluated the potential anti-aging benefits of a Q-ter based nutritional mixture (commercially known as Eufortyn) mainly containing the following compounds: terclatrated coenzyme Q(10) (Q-ter), creatine and a standardized ginseng extract. We found that Eufortyn supplementation significantly ameliorated the age-associated decreases in grip strength and gastrocnemius subsarcolemmal mitochondria Ca(2+) retention capacity when initiated in male Fischer344 x Brown Norway rats at 21 months, but not 29 months, of age. Moreover, the increases in muscle RNA oxidation and subsarcolemmal mitochondrial protein carbonyl levels, as well as the decline of total urine antioxidant power, which develop late in life, were mitigated by Eufortyn supplementation in rats at 29 months of age. CONCLUSIONS/SIGNIFICANCE: These data imply that Eufortyn is efficacious in reducing oxidative damage, improving the age-related mitochondrial functional decline, and preserving physical performance when initiated in animals at early midlife (21 months). The efficacy varied, however, according to the age at which the supplementation was provided, as initiation in late middle age (29 months) was incapable of restoring grip strength and mitochondrial function. Therefore, the Eufortyn supplementation may be particularly beneficial when initiated prior to major biological and functional declines that appear to occur with advancing age.

Peroxisome proliferator-activated receptor activation by a short-term feeding of zingerone in aged rats.

Peroxisome proliferator-activated receptors (PPARs), members of the nuclear hormone receptor family, are key regulators of various metabolic pathways related to lipid and glucose metabolism as well as inflammation. We examined the effect of zingerone, a major ingredient of ginger, on PPAR, hepatic nuclear factor-4 (HNF-4), and nuclear factor-kappaB (NF-kappaB) expression in 21-month-old male Sprague-Dawley rats. Two experimental groups receiving doses of either 2 or 8 mg/kg/day zingerone for 10 days were compared with young rats (6 months old) and an age-matched control group. For molecular work, the endothelial cell line YPEN-1 was used. Both the 2 and 8 mg/kg/day dose of zingerone significantly increased DNA binding activities of PPARs (2.8-fold). Expression of HNF-4 was also increased in the group receiving the 8 mg/kg/day dose. We further showed that zingerone partially prevented the age-related decline in PPAR expression. In vitro experiments revealed zingerone (10 microM) increased PPAR expression (2.5-fold) to a similar extent as the PPAR agonist fibrate (5 microM) and suppressed pro-inflammatory transcription factor NF-kappaB activity. Collectively, our findings suggest that zingerone exerts its potent anti-inflammatory action by increasing HNF-4 and PPAR activities, while suppressing NF-kappaB activity.