Sirtuins are evolutionarily conserved protein, serving as nicotinamide adenine dinucleotide-dependent deacetylases or adenosine diphosphate-ribosyltransferases. The mammalian sirtuins family, including SIRT1~7, is involved in many biological processes such as cell survival, proliferation, senescence, stress response, genome stability and metabolism. Evidence accumulated over the past two decades has indicated that sirtuins not only serve as important energy status sensors but also protect cells against metabolic stresses. In this review, we summarize the background of glucose and lipid metabolism concerning sirtuins and discuss the functions of sirtuins in glucose and lipid metabolism. We also seek to highlight the biological roles of certain sirtuins members in cancer metabolism.

A total of 320 male Arbor Acres broiler chickens (28 days old) were randomly allotted to one of the three experimental diets supplemented with 0 (160 birds), 600 (80 birds) or 1200 mg/kg (80 birds) creatine monohydrate (CMH) for 14 days. On the morning of 42 day, after an 8-h fast, the birds of CMH-free group were divided into two equal groups, and all birds of these four groups were transported according to the follow protocol: 0.75-h transport without CMH supplementation (as a lower stress control group), 3-h transport without CMH supplementation, 3-h transport with 600 or 1200 mg/kg CMH supplementation. Each treatment group was composed of 8 replicates with 10 birds each. The results showed that supplementation of CMH for 14 days before slaughter did not affect the overall growth performance and carcass traits of stressed broilers (P>0.05). A 3-h transport decreased plasma glucose concentration, elevated plasma corticosterone concentration, increased bird live weight loss, breakdown of muscle glycogen, as well as the accumulation of muscle lactate (P<0.05), which induced some detrimental changes to breast meat quality (lower ultimate pH and higher drip loss, P<0.05). Nevertheless, supplementation of 1200 mg/kg CMH reduced chicken weight loss, decreased the contents of lactate and glycolytic potential in pectoralis major of 3-h transported broilers (P<0.05), which is beneficial to maintain breast meat quality by reducing the drip loss (P<0.05). These findings suggest that the reduction of muscle glycolysis is probably the reason for maintainance of meat quality by supplementation of CMH in transported broilers.

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Although non-segmental vitiligo (NSV) results from the autoimmune destruction of melanocytes, the detailed immune mechanisms have not yet been fully elucidated. Th17 cells have been identified to be implicated in human autoimmune diseases. In this study, the frequencies of peripheral blood Th17 cells and serum levels of IL-17A and Th17 cell-related cytokines were examined in 45 patients with active NSV compared to 45 race-, gender-, and age-matched healthy controls. Our results showed increased circulating Th17 cell frequencies and elevated serum IL-17A, TGF-β1, and IL-21 levels in patients with NSV. Meanwhile, the increased Th17 cell frequencies are positively correlated with serum TGF-β1 level, and the body surface area of lesions is positively correlated with elevated TGF-β1 and IL-21 levels and Th17 cell frequencies. Furthermore, positive correlation was identified between Th17 and Th1 cell frequencies in patients with NSV. These results further indicate the potential involvement of Th17 cells and the collaborative contribution of Th17 and Th1 in NSV development, and suggest that the elevated serum TGF-β1 and IL-21 levels could contribute to enhanced Th17 cell differentiation in NSV.

Salt-inducible kinase 2 (SIK2) has been established as a regulator of diverse biological processes including cell metabolism. A recent study has reported that SIK2 is required for adipocyte-induced ovarian cancer (OC) survival through facilitating fatty acid oxidation. However, whether SIK2 also plays a role in the lipid synthesis in OC cells remains elusive. Here, we showed that SIK2 significantly promoted the lipid synthesis in OC cells. On the one hand, SIK2 enhanced fatty acid synthesis through upregulating the expression of sterol regulatory element binding protein 1c (SREBP1c) and thus the transcription of major lipogenic enzyme FASN. On the other hand, SIK2 promoted cholesterol synthesis through upregulating the expression of sterol regulatory element binding protein 2 (SREBP2) and thus the transcription of major cholesterol synthesis enzymes HMGCR. Moreover, PI3K/Akt signaling pathway was found to be involved in the upregulation of SREBP1c and SREBP2 in OC cells. Moreover, in vitro and in vivo assays indicated that the SIK2-regulated fatty acid and cholesterol synthesis played a critical role in the growth of OC cells. Our findings demonstrate that SIK2 is a critical regulator of lipid synthesis in OC cells and thus promotes OC growth, which provides a strong line of evidence for this molecule to be used as a therapeutic target in the treatment of this malignancy.

Summary Although it is widely believed that non-segmental vitiligo (NSV) results from the autoimmune destruction of melanocytes, a clear understanding of defects in immune tolerance, which mediate this uncontrolled self-reactivity, is still lacking. In the present study, we systemically evaluated circulating regulatory T (Treg) cells, including CD4+CD25+FoxP3+ Treg cells and invariant natural killer T (iNKT) cells, as well as naïve and memory CD4+ and CD8+ T cells and their cytokine production, in a cohort of 43 progressive NSV patients with race-, gender-, and age-matched healthy controls. We found that the general immunophenotypes of CD4+ and CD8+ T cells and the percentage of CD4+CD25+FoxP3+ Tregs were comparable between NSV and healthy controls. However, percentages of peripheral iNKT cells were significantly decreased in NSV patients compared to that in healthy controls. Our data confirm the previous notion that the percentage of peripheral CD4+CD25+FoxP3+ Tregs remains unaltered in NSV and suggests the involvement of defective iNKT cells in the pathogenesis of NSV.

Summary Freezing and thawing technologies are widely used in meat industry. This study aimed to investigate the effects of freezing and different thawing methods (Control group, CG; water immersing thawing, WT; low temperature combined with high‐humidity thawing, LT; combined thawing 1 (WT 15 min, then LT), CT1; combined thawing 2 (LT 2 h, then WT), CT2) on the quality of chicken breast. The results showed that all thawing methods significantly increased shear force value, the gap between muscle fibres, the contents of malondialdehyde (MDA) and carbonyl compounds, meanwhile, decreased the pH, CIE a* value, total protein solubility and sarcoplasmic protein solubility, compared with CG (P < 0.05). Among different thawing methods, LT was most effective in decreasing thawing loss but it had the highest contents of MDA and carbonyl compounds (P < 0.05). CT1 significantly decreased shear force value and MDA content (P < 0.05). Overall, freezing and thawing process had a detrimental effect on the quality of chicken breast, and the extent was pronounced with different thawing methods. On the basis of shortening thawing time and keeping meat quality, the results of this study suggested that CT1 could be chosen as the better thawing method.