SIRT7 depletion inhibits cell proliferation, migration, and increases drug sensitivity by activating p38MAPK in breast cancer cells.

SIRT7 is a member of the sirtuin family of proteins that are known to be associated with tumor development. However, the functional roles and molecular mechanisms underlying the function of SIRT7 in breast cancer cell survival and tumor development remain unclear. Recent studies demonstrated that SIRT7 is upregulated in breast cancer cells and tissues. In the present study, we systematically explored the roles of SIRT7 in the growth of breast cancer cells and tumors both in vitro and in vivo. Our results showed that SIRT7 plays a major role in facilitating cell survival by promoting cell proliferation and inhibiting apoptosis. SIRT7 depletion significantly inhibited cell invasion and wound healing by blocking cell cycle progression and inducing cell apoptosis. Meanwhile, SIRT7 depletion can increase the sensitivity of breast cancer cells to doxorubicin (DOX). Xenograft model studies showed that stable silencing of SIRT7 inhibited tumor growth and enhanced tumor sensitivity to DOX. Further research revealed that p38MAPK is involved in SIRT7-mediated regulation of breast cancer cell proliferation and tumor growth. Taken together, our results showed that SIRT7 plays a critical role in breast cancer cell survival, migration, and tumor growth, and increased the efficiency of DOX treatment both in vitro and in vivo. Therefore, SIRT7 is a promising therapeutic target in breast cancer treatment.

Research progress on the mechanisms underlying poultry immune regulation by plant polysaccharides.

With the rapid development of poultry industry and the highly intensive production management, there are an increasing number of stress factors in poultry production. Excessive stress will affect their growth and development, immune function, and induce immunosuppression, susceptibility to a variety of diseases, and even death. In recent years, increasing interest has focused on natural components extracted from plants, among which plant polysaccharides have been highlighted because of their various biological activities. Plant polysaccharides are natural immunomodulators that can promote the growth of immune organs, activate immune cells and the complement system, and release cytokines. As a green feed additive, plant polysaccharides can not only relieve stress and enhance the immunity and disease resistance of poultry, but also regulate the balance of intestinal microorganisms and effectively alleviate all kinds of stress faced by poultry. This paper reviews the immunomodulatory effects and molecular mechanisms of different plant polysaccharides (Atractylodes macrocephala Koidz polysaccharide, Astragalus polysaccharides, Taishan Pinus massoniana pollen polysaccharide, and alfalfa polysaccharide) in poultry. Current research results reveal that plant polysaccharides have potential uses as therapeutic agents for poultry immune abnormalities and related diseases.

SIRT7 Regulates Lipopolysaccharide-Induced Inflammatory Injury by Suppressing the NF-κB Signaling Pathway.

Mastitis has severely affected the cattle industry worldwide and has resulted in decreased dairy production and cattle reproduction. Although prevention and treatment methods have been implemented for decades, cattle mastitis is still an intractable disease. Sirtuin 7 (SIRT7) is an NAD+-dependent deacetylase that is involved in various biological processes, including ribosomal RNA synthesis and protein synthesis, DNA damage response, metabolism, and tumorigenesis. However, whether SIRT7 participates in inflammation remains unknown. Our results revealed that SIRT7 is downregulated in tissue samples from mastitic cattle. Therefore, we isolated dairy cow mammary epithelial cells (DCMECs) from breast tissues and developed an in vitro model of lipopolysaccharide- (LPS-) induced inflammation to examine SIRT7 function and its potential role in inflammation. We showed that SIRT7 was significantly downregulated in LPS-treated DCMECs. SIRT7 knockdown significantly increased the LPS-stimulated production of inflammatory mediators, like reactive oxygen and nitric oxide, and upregulated TAB1 and TLR4. In addition, SIRT7 knockdown significantly increased the phosphorylation of TAK1 and NF-κBp65 in LPS-treated DCMECs. Moreover, SIRT7 knockdown promoted the translocation of NF-κBp-p65 to the cell nucleus and then increased the secretion of inflammatory cytokines (IL-1ß and IL-6). In contrast, SIRT7 overexpression had the opposite effects when compared to SIRT7 knockdown in LPS-treated DCMECs. In addition, SIRT7 overexpression attenuated LPS-induced DCMEC apoptosis. Taken together, our results indicate that SIRT7 can suppress LPS-induced inflammation and apoptosis via the NF-κB signaling pathway. Therefore, SIRT7 may be considered as a potential pharmacological target for clinical mastitis therapy.

Optimization of medium composition for butyric acid production by Clostridium thermobutyricum using response surface methodology.

The optimal medium for butyric acid production by Clostridium thermobutyricum in a shake flask culture was studied using statistical experimental design and analysis. The optimal composition of the fermentation medium for maximum butyric acid yield, as determined on the basis of a three-level four-factor Box-Behnken design (BBD), was obtained by response surface methodology (RSM). The high correlation between the predicted and observed values indicated the validity of the model. A maximum butyric acid yield of 12.05 g/l was obtained at K(2)HPO(4) 7.2 g/l, 34.9 g/l glucose, 20 g/l yeast extract, and 15 g/l acetate, which compared well to the predicated production of 12.13 g/l.