[Total saponins of Panax japonicus alleviates CCl4-induced acute liver injury in rats by regulating the PI3K/AktNF-κB signaling pathway].

OBJECTIVE: To investigate the protective effect of total saponins of Panax japonicus (TSPJ) against CCl4-induced acute liver injury (ALI) in rats and explore the underlying pharmacological mechanisms. METHODS: Male SD rat models of CCl4-induced ALI were given intraperitoneal injections of distilled water, 100 mg/kg biphenyl bisabololol, or 50, 100, and 200 mg/kg TSPJ during modeling (n=8). Liver functions (AST, ALT, TBil and ALP) of the rats were assessed and liver pathologies were observed with HE staining. Immunohistochemistry was used to detect the expressions of PI3K/Akt/NF-κB signaling pathway molecules in liver tissue; ELISA was used to determine the levels of T-SOD, GSH-Px, and MDA. Western blotting was performed to detect the expression levels of PI3K-Akt and SIRT6-NF-κB pathways in the liver tissue. RESULTS: Network pharmacological analysis indicated that the key pathways including PI3K/Akt mediated the therapeutic effect of TSPJ on ALI. In the rat models of ALI, treatments with biphenyl bisabololol and TSPJ significantly ameliorated CCl4-induced increase of serum levels AST, ALT, ALP, TBil and MDA and decrease of T-SOD and GSH-Px levels (all P < 0.01). The rat models of ALI showed significantly increased expression of p-NF-κB (P < 0.01), decreased expressions of PI3K, p-Akt and SIRT6 proteins, and elevated expression levels of p-NF-κB, TNF-α and IL-6 proteins in the liver, which were all significantly improved in the treatment groups (P < 0.05 or 0.01). CONCLUSION: TSPJ can effectively alleviate CCl4-induced ALI in rats by suppressing inflammatory responses and oxidative stress in the liver via regulating the PI3K/Akt and SIRT6/NF-κB pathways.

Sirtuin 6 ameliorates arthritis through modulating cyclic AMP-responsive element binding protein/CCN1/cyclooxygenase 2 pathway in osteoblasts.

INTRODUCTION: CCN1 is an immediate-early gene product pivotal for arthritis progression. We have previously shown that sirtuin 6 (SIRT6) inhibited hypoxia-induced CCN1 expression in osteoblasts. Herein we examined the contribution of cyclic AMP-responsive element binding protein (CREB)/CRE to this suppressive action and the influence of CCN1 on cyclooxygenase (COX) 2 synthesis. MATERIALS AND METHODS: MC3T3-E1 murine osteoblasts were cultured under normoxia (21% oxygen) or hypoxia (2% oxygen). Expressions of CCN1, phospho-CREB (Ser133), COX2 and relevant kinases were assessed by Western blot. SIRT6 was overexpressed in cultured osteoblasts and arthritic joints by a lentiviral-based technique. Activities of CCN1 gene promoter constructs were examined by luciferase reporter assay. Interaction between CREB and CCN1 promoter was assessed by chromatin immunoprecipitation (ChIP). Collagen-induced arthritis (CIA) was established in 20 rats to evaluate the effects of SIRT6 therapy on osteoblastic expressions of phospho-CREB, CCN1 and COX2. RESULTS: SIRT6 suppressed hypoxia-enhanced CCN1 expression and CREB phosphorylation. Attenuation of calcium/calmodulin-dependent protein kinase II (CaMKII) may be responsible for SIRT6-induced CREB inhibition. CRE at - 286 bp upstream of the ATG start codon was essential for CCN1 expression under hypoxia and SIRT6 reduced hypoxia-stimulated CREB/CRE interaction. Forced expression of CREB rescued SIRT6-suppressed CCN1 synthesis. CCN1 induced COX2 expression in osteoblasts. In rat CIA, the therapeutic effect of SIRT6 was accompanied by decreases in osteoblastic expressions of phospho-CREB, CCN1 and COX2. CONCLUSION: Our study indicated that the benefits of SIRT6 to inflammatory arthritis and bone resorption are at least partially derived from its modulation of CREB/CCN1/COX2 pathway in osteoblasts.

Sulforaphane-cisplatin combination inhibits the stemness and metastatic potential of TNBCs via down regulation of sirtuins-mediated EMT signaling axis.

BACKGROUND: Sulforaphane (SFN) is a naturally occurring organosulfur compound found in cruciferous vegetables such as broccoli, brussels sprouts and cabbage. SFN is known for its multiple therapeutic properties, such as HDAC inhibitory, chemo preventive and anti-cancer effects. Cisplatin (CIS) has limited effect against metastatic triple-negative breast cancer (TNBC). Additionally, CIS impose severe side effects to normal cells, and later TNBC cells develops resistance. Studies suggest that the overexpression of sirtuins (SIRTs) promotes CIS resistance and metastasis by activating epithelial-to-mesenchymal transition (EMT) pathway in TNBC. PURPOSE: In view of the above information, we investigated the therapeutic efficacy of SFN, in combination with CIS against TNBC metastasis and CIS resistance. METHODS: The anti-cancerous effect of SFN-CIS combination on human TNBC cell lines was demonstrated by utilizing MTT assay and, apoptosis and cell cycle assay followed by FACS analysis. The synergistic effect of SFN-CIS combination on the experimental metastasis was demonstrated by utilizing migration, invasion, chemotaxis, mammosphere and colony formation assay on human TNBC MDA-MB-231 and MDA-MB-468 cells. The role of SIRTs-mediated EMT signaling axis in the metastasis and chemoresistance was investigated by western blotting technique as well as sirtuin activity tests. This was further validated by using Chromatin immunoprecipitation (ChIP) analysis. RESULTS: We found that SFN-CIS combination synergistically inhibits cellular growth of MDA-MB-231 and MDA-MB-468 cells. More importantly, SFN was found to protect normal kidney cells from CIS-induced toxicity. Further, SFN-CIS combination was found to synergistically inhibit metastatic-events via significantly altering EMT markers which was further associated with the suppression of SIRTs functions in TNBC cells. ChIP analysis validated that SFN-CIS combination suppresses EMT mechanism through altered chromatin modifications at E-cadherin promoter resulting in its re-expression. CONCLUSION: The results of the current study suggests that CIS when supplemented with SFN, inhibits metastasis and stemness potential of TNBC cells by down regulating SIRTs-mediated EMT cascade. Overall this study affirms that, this novel combination could be a promising strategy against SIRT-mediated TNBC metastasis and CIS-resistance.

Antioxidant supplementation during in vitro culture improves mitochondrial function and development of embryos from aged female mice.

Maternal aging results in reduced oocyte and blastocyst quality, thought to be due, in part, to mitochondrial dysfunction and accumulation of reactive oxygen species. To reduce oxidative stress, the antioxidants α-lipoic acid (ALA; 10µM), α-tocopherol (250µM), hypotaurine (1mM) and N-acetylcysteine (NAC; 1mM), and sirtuin (100ngmL(-1)) were added to embryo culture medium (AntiOX) and compared with a control (CON) without antioxidants to assess blastocyst development after in vitro maturation and fertilisation of oocytes from aged B6D2F1 female mice (13.5 months). Development to the blastocyst stage increased in the AntiOX compared with CON group (87.6% vs 72.7%, respectively; P<0.01), in addition to higher mitochondrial membrane potential and ATP levels in the AntiOX group. Expression of genes associated with oxidative stress (PI3K, FOXO3A and GLRX2) was upregulated in the CON compared with AntiOX group. In addition to AntiOX, a medium containing only NAC and ALA (rAntiOX) was used to culture embryos from young CF1 females (6-8 weeks). More blastocysts developed in the rAntiOX compared with CON group (64.1% vs 43.3%, respectively; P<0.01), although AntiOX (48.0% blastocysts) did not result in improved development in young mice. Antioxidants improved mitochondrial activity, gene expression and development in embryos of older female mice, whereas a reduced level of antioxidants during culture was beneficial to embryos from young mice.