SIRT3 Regulates Clearance of Apoptotic Cardiomyocytes by Deacetylating Frataxin.

BACKGROUND: Efferocytosis is an activity of macrophages that is pivotal for the resolution of inflammation in hypertension. The precise mechanism by which macrophages coordinate efferocytosis and internalize apoptotic cardiomyocytes remains unknown. The aim of this study was to determine whether SIRT3 (sirtuin-3) is required for both apoptotic cardiomyocyte engulfment and anti-inflammatory responses during efferocytosis. METHODS: We generated myeloid SIRT3 knockout mice and FXN (frataxin) knock-in mice carrying an acetylation-defective lysine to arginine K189R mutation (FXNK189R). The mice were given Ang II (angiotensin II) infusion for 7 days. We analyzed cardiac macrophages' mitochondrial iron levels, efferocytosis activity, and phenotype both in vivo and in vitro. RESULTS: We showed that SIRT3 deficiency exacerbated Ang II-induced downregulation of the efferocytosis receptor MerTK (c-Mer tyrosine kinase) and proinflammatory cytokine production, accompanied by disrupted mitochondrial iron homeostasis in cardiac macrophages. Quantitative acetylome analysis revealed that SIRT3 deacetylated FXN at lysine 189. Ang II attenuated SIRT3 activity and enhanced the acetylation level of FXNK189. Acetylated FXN further reduced the synthesis of ISCs (iron-sulfur clusters), resulting in mitochondrial iron accumulation. Phagocytic internalization of apoptotic cardiomyocytes increased myoglobin content, and derived iron ions promoted mitochondrial iron overload and lipid peroxidation. An iron chelator deferoxamine improved the levels of MerTK and efferocytosis, thereby attenuating proinflammatory macrophage activation. FXNK189R mice showed improved macrophage efferocytosis, reduced cardiac inflammation, and suppressed cardiac fibrosis. CONCLUSIONS: The SIRT3-FXN axis has the potential to resolve cardiac inflammation by increasing macrophage efferocytosis and anti-inflammatory activities.

Fibroblast-to-cardiomyocyte lactate shuttle modulates hypertensive cardiac remodelling.

BACKGROUND: Cardiac fibroblasts (CFs) and cardiomyocytes are the major cell populations in the heart. CFs not only support cardiomyocytes by producing extracellular matrix (ECM) but also assimilate myocardial nutrient metabolism. Recent studies suggest that the classical intercellular lactate shuttle may function in the heart, with lactate transported from CFs to cardiomyocytes. However, the underlying mechanisms regarding the generation and delivery of lactate from CFs to cardiomyocytes have yet to be explored. RESULTS: In this study, we found that angiotensin II (Ang II) induced CFs differentiation into myofibroblasts that, driven by cell metabolism, then underwent a shift from oxidative phosphorylation to aerobic glycolysis. During this metabolic conversion, the expression of amino acid synthesis 5-like 1 (GCN5L1) was upregulated and bound to and acetylated mitochondrial pyruvate carrier 2 (MPC2) at lysine residue 19. Hyperacetylation of MPC2k19 disrupted mitochondrial pyruvate uptake and mitochondrial respiration. GCN5L1 ablation downregulated MPC2K19 acetylation, stimulated mitochondrial pyruvate metabolism, and inhibited glycolysis and lactate accumulation. In addition, myofibroblast-specific GCN5L1-knockout mice (GCN5L1fl/fl: Periostin-Cre) showed reduced myocardial hypertrophy and collagen content in the myocardium. Moreover, cardiomyocyte-specific monocarboxylate transporter 1 (MCT1)-knockout mice (MCT1fl/fl: Myh6-Cre) exhibited blocked shuttling of lactate from CFs to cardiomyocytes and attenuated Ang II-induced cardiac hypertrophy. CONCLUSIONS: Our findings suggest that GCN5L1-MPC2 signalling pathway alters metabolic patterns, and blocking MCT1 interrupts the fibroblast-to-cardiomyocyte lactate shuttle, which may attenuate cardiac remodelling in hypertension.

Angiotensin II-Induced Erythrocyte Senescence Contributes to Oxidative Stress.

Oxidative stress may be an important cause of erythrocyte senescence. Angiotensin II (Ang II) has recently been shown to promote vascular cell senescence. However, its effects on erythrocytes remain unclear. This study aims at investigating the role of Ang II in regulating erythrocyte lifespan through oxidative stress. Experiments were performed in C57/BL6J mice infused with Ang II (1500 ng/kg per minute) or saline for 7 days. After Ang II infusion, we found that Ang II increased erythrocyte number, hemoglobin, and red blood cell distribution width. These differences were accompanied by a decrease in glutathione (GSH) and an increase in malondialdehyde (MDA) concentration. In vitro, after 24 hours of Ang II treatment, erythrocytes showed reduced surface expression of CD47 and increased phosphatidylserine exposure. In parallel, Ang II reduced the levels of antioxidant enzymes, including Cu/ZnSOD, catalase, and peroxidase 2 (PRDX2). These effects were reversed by the addition of the antioxidant N-acetyl-L-cysteine or the Ang II type 1 (AT1) receptor blocker losartan. In addition, Ang II treatment increased pro-inflammatory oxylipin, including hydroxyeicosatetraenoic acids (HETEs) and dihydroxyoctadecenoic acids (DiHOMEs), in the erythrocyte membranes. Collectively, Ang II induced erythrocyte senescence and susceptibility to eryptosis, partially due to enhanced oxidative stress.

Sirtuin 3 governs autophagy-dependent glycolysis during Angiotensin II-induced endothelial-to-mesenchymal transition.

The impairment of autophagy can cause cellular metabolic perturbations involved in endothelial-to-mesenchymal transition (EndoMT). However, the interplay between the cellular autophagy machinery and endothelial metabolism remains elusive. Sirtuin 3 (SIRT3), an NAD-dependent deacetylase, is a major cellular sensor of energy metabolism. The aim of this work was to determine the role of SIRT3-mediated autophagy in cellular metabolism and the process of EndoMT. We demonstrated that Angiotensin II (Ang II) led to defective autophagic flux and high levels of glycolysis in endothelial cells (ECs) accompanied by a loss of mitochondrial SIRT3 during EndoMT. The loss of SIRT3 further induced the hyperacetylation of endogenous autophagy-regulated gene 5 (ATG5), which in turn inhibited autophagosome maturation and increased pyruvate kinase M2 (PKM2) dimer expression. The M2 dimer is the less active form of PKM2, which drives glucose through aerobic glycolysis. Additionally, TEPP-46, a selective PKM2 tetramer activator, produced lower concentrations of lactate and led to the reduction of EndoMT both in vitro and in vivo. In parallel, the blockade of lactate influx from ECs into vascular smooth muscle cells (VSMCs) downregulated synthetic VSMC markers. EC-specific SIRT3 transgenic mice exhibited reduced endothelial cell transition but partial rescue of vascular fibrosis and collagen accumulation. Taken together, these findings reveal that SIRT3 regulates EndoMT by improving the autophagic degradation of PKM2. Pharmacological targeting of glycolysis metabolism may, therefore, represent an effective therapeutic strategy for hypertensive vascular remodeling.

Sirtuin 3-mediated pyruvate dehydrogenase activity determines brown adipocytes phenotype under high-salt conditions.

Previous study indicated that Sirtuin 3 (SIRT3) is a central regulator of adaptive thermogenesis in brown adipose tissue (BAT). Here we investigate the role of SIRT3 in the modulation of cellular phenotype in BAT under high salt intake (HS). HS downregulated SIRT3 level in BAT, accompanied by decreased oxygen consumption rate, and caused a severe loss of BAT characteristics. Mechanically, SIRT3 interacted with pyruvate dehydrogenase E1α (PDHA1) and deacetylated Lys-83 both in vitro and in vivo under HS. In parallel, HS suppressed salt-induced kinase (Sik) 2 phosphorylation. Silencing Sik2 further diminished SIRT3 activity and enhanced acetylation of PDHA1 K83 level. Reconstruction of SIRT3 restored PDH activity and thermogenic markers expression in differentiated brown adipocytes from SIRT3 knockout (KO) mice. In addition, loss of SIRT3 induced selective remodelling of phospholipids and glycerolipids in BAT exposure to HS. These data indicate that SIRT3 is an essential enzymatic switch that controls brown adipose cell phenotype.

Nebivolol Improves Obesity-Induced Vascular Remodeling by Suppressing NLRP3 Activation.

Nebivolol is a novel ß-adrenergic receptor (ß-AR) blocker with anti-inflammatory and antioxidant properties. The NLRP3 inflammasome plays a pivotal role in the pathogenesis of obesity-induced vascular dysfunction. Our study aimed to explore the effect of nebivolol on the NLRP3 inflammasome and vascular remodeling in diet-induced obese rats. Eight-week-old Sprague-Dawley male rats were fed with either a standard chow diet or a high-fat diet (HFD) for 8 weeks. Next, the obese rats were subdivided into 3 groups as follows: (1) HFD control group, (2) HFD with low doses of nebivolol (5 mg/kg·d), and (3) HFD with high doses of nebivolol (10 mg/kg·d). A 4-week treatment with nebivolol improved acetylcholine-induced vascular relaxation in accordance with an increased aortic endothelial nitric oxide synthase. Nebivolol attenuated NLRP3 inflammasome activation and suppressed autophagy. In parallel, nebivolol enhanced the levels of phase-II detoxifying enzymes, including superoxide dismutase and catalase. These effects were associated with an increased ß3-AR level. Moreover, nebivolol treatment significantly increased Adenosine 5'-monophosphate (AMP)-activated protein kinase activity and decreased phosphorylation of the mammalian target of rapamycin. These results demonstrated that nebivolol improves obesity-induced vascular remodeling by attenuating NLRP3 inflammasome activation and restoring the antioxidant defense.

Sirtuin 3-induced macrophage autophagy in regulating NLRP3 inflammasome activation.

Defective autophagy of monocytes or macrophages might result in NLRP3 inflammasome activation and cause vascular metabolic inflammation. However, the mechanism underlying the initiation of the autophagy response to hyperlipidaemia remains unclear. Sirtuin 3 (SIRT3), an NAD-dependent deacetylase, is sensitive to the metabolic status and mediates adaptation responses. In this study, we investigated the role of SIRT3-mediated autophagy in regulating NLRP3 inflammasome activation. We determined that the inhibition of autophagy and the activation of the NLRP3 inflammasome were concomitant with reduced SIRT3 levels both in peripheral blood monocytes from obese humans and in palmitate-treated THP-1 cells. Furthermore, we demonstrated that SIRT3 could form a molecular complex with ATG5, while SIRT3 overexpression altered the acetylation of endogenous ATG5. ATG5 acetylation inhibited autophagosome maturation and induced NLRP3 inflammasome activation. In parallel, SIRT3 overexpression in THP-1 cells decreased the palmitate-induced generation of mitochondrial reactive oxygen species, restored autophagy, and attenuated NLRP3 inflammasome activation. The incubation of human aortic endothelial cells (HAECs) with macrophage-conditioned medium (MCM) induced HAEC expression of vascular cell adhesion molecule-1, intercellular adhesion molecule 1, α-smooth muscle actin, and collagen-1. The effect of MCM could be reversed by the addition of neutralizing anti-IL-1ß antibody or the overexpression of SIRT3. Consistent with this, en face analyses displayed a marked increase in α-SMC-positive endothelial cells in SIRT3-/- mice with acute hyperlipidaemia. Taken together, these findings revealed that SIRT3-deficient macrophages displayed impaired autophagy and accelerated NLRP3 inflammasome activation and endothelial dysfunction.

Sirtuin 3 Deficiency Accelerates Hypertensive Cardiac Remodeling by Impairing Angiogenesis.

BACKGROUND: Emerging evidence indicates that impaired angiogenesis may contribute to hypertension-induced cardiac remodeling. The nicotinamide adenine dinucleotide-dependent deacetylase Sirtuin 3 (SIRT3) has the potential to modulate angiogenesis, but this has not been confirmed. As such, the aim of this study was to examine the relationship between SIRT3-mediated angiogenesis and cardiac remodeling. METHODS AND RESULTS: Our experiments were performed on SIRT3 knockout and age-matched wild-type mice infused with angiotensin II (1400 ng/kg per minute) or saline for 14 days. After angiotensin II infusion, SIRT3 knockout mice developed more severe microvascular rarefaction and functional hypoxia in cardiac tissues compared with wild-type mice. These events were concomitant with mitochondrial dysfunction and enhanced collagen I and collagen III expression, leading to cardiac fibrosis. Silencing SIRT3 facilitated angiotensin II-induced aberrant Pink/Parkin acetylation and impaired mitophagy, while excessive mitochondrial reactive oxygen species generation limited angiogenic capacity in primary mouse cardiac microvascular endothelial cells. Moreover, SIRT3 overexpression in cardiac microvascular endothelial cells enhanced Pink/Parkin-mediated mitophagy, attenuated mitochondrial reactive oxygen species generation, and restored vessel sprouting and tube formation. In parallel, endothelial cell-specific SIRT3 transgenic mice showed decreased fibrosis, as well as improved cardiac function and microvascular network, compared with wild-type mice with similar stimuli. CONCLUSIONS: Collectively, these findings suggest that SIRT3 could promote angiogenesis through attenuating mitochondrial dysfunction caused by defective mitophagy.

Haematopoietic TLR4 deletion attenuates perivascular brown adipose tissue inflammation in atherosclerotic mice.

AIMS: To investigate whether haematopoietic TLR4 deletion attenuates perivascular brown adipose tissue inflammation in atherosclerotic mice. METHODS AND RESULTS: Experiments were performed using irradiated LDL receptor-deficient (LDLR-/-) mice with marrow from either TLR4-deficient (TLR4-/-) or age-matched wild-type (WT) mice. After 12 weeks of being fed a high-cholesterol diet, TLR4-/-→LDLR-/- mice developed fewer atherosclerotic lesions in the aorta compared to WT→LDLR-/- mice. This effect was associated with an increase in multilocular lipid droplets and mitochondria in perivascular adipose tissue (PVAT). Immunofluorescence analysis confirmed that there was an increase in capillary density and M2 macrophage infiltration, accompanied by a decrease in tumour necrosis factor (TNF)-α expression in the localized PVAT of TLR4-/-→LDLR-/- mice. In vitro studies indicated that bone marrow-derived macrophages (BMDMs) from WT mice demonstrated an M1-like phenotype and expression of inflammatory cytokines induced by palmitate. These effects were attenuated in BMDMs isolated from TLR4-/- mice. Furthermore, brown adipocytes incubated with conditioned medium (CM) derived from palmitate-treated BMDMs, exhibited larger and more unilocular lipid droplets, and reduced expression of brown adipocyte-specific markers and perilipin-1 compared to those observed in brown adipocytes exposed to CM from palmitate-treated BMDMs of TLR4-/- mice. This decreased potency was primarily due to TNF-α, as demonstrated by the capacity of the TNF-α neutralizing antibody to reverse these effects. CONCLUSIONS: These results suggest that haematopoietic-specific deletion of TLR4 promotes PVAT homeostasis, which is involved in reducing macrophage-induced TNF-α secretion and increasing mitochondrial biogenesis in brown adipocytes.

Nebivolol Ameliorates Cardiac NLRP3 Inflammasome Activation in a Juvenile-Adolescent Animal Model of Diet-Induced Obesity.

NLRP3 is involved in obesity-induced cardiac remodeling and dysfunction. In this study, we evaluated whether the cardiac protective effects of nebivolol relied on attenuating NLRP3 activation in a juvenile-adolescent animal model of diet-induced obesity. Weaning male Sprague-Dawley rats were fed with either a standard chow diet (ND) or a high-fat diet (HFD) for 8 weeks. The obese rats were subsequently subdivided into three groups: 1) HFD control group; 2) HFD with low-dose nebivolol (5 mg/kg/d); 3) HFD with high-dose nebivolol (10 mg/kg/d). Treatment with nebivolol prevented HFD-induced obesity associated excess cardiac lipid accumulation as well as myocardial mitochondrial dysfunction. Nebivolol attenuated pro-inflammatory cytokines secretion and NLRP3 inflammasome activation in myocardium of obese rats. In parallel, nebivolol treatment of obese animals increased cardiac ß3-AR expression, reversing the reduction of endothelial nitric oxide synthase (eNOS). In vitro, nebivolol treatment of palmitate-incubated H9C2 cells suppressed autophagy, restored mitochondrial biogenesis, leading to decreased mitochondrial reactive oxygen species (mtROS) generation, and suppressed NLRP3 inflammasome activation. Meanwhile the presence of shRNA against ß3-AR or against eNOS deteriorated the protective effects of nebivolol. These data suggest the beneficial effect of nebivolol on myocardial lipotoxicity contributing to inhibiting NLRP3 inflammasome activation possibly via improved mitochondrial dysfunction.

B7-H3, B7-H4, Foxp3 and IL-2 expression in cervical cancer: Associations with patient outcome and clinical significance.

The aim of this study was to determine the expression of B7-H3, B7-H4, Foxp3 and IL-2 in cervical cancer tissues, and evaluate the corresponding clinical significance. The expression of B7-H3, B7-H4, Foxp3 and IL-2 in 108 cervical cancer specimens was detected using immunohistochemistry, and their relationship with clinicopathologic parameters was determined. B7-H3, B7-H4 and Foxp3 had high levels of expression in cervical cancer cells (72.22, 80.56, and 91.56%, respectively). B7-H3 levels were only significantly associated with tumor size (P=0.013), while B7-H4, Foxp3 and IL-2 levels were significantly associated with International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.023, 0.014 and 0.036, respectively) and tumor size (P=0.045, 0.010 and 0.021, respectively). Their expression levels were not correlated with age, histologic type, differentiation and lymph node metastasis (all P>0.05). Cox regression multivariate analysis confirmed that B7-H3 or B7-H4 overexpression was an independent prognostic factor. In addition, there were significant positive relationships between the expression of B7-H3 and B7-H4 with Foxp3 (P<0.001). In contrast, the expression of B7-H3 and B7-H4 was negatively correlated with IL-2 (P<0.05). B7-H3, B7-H4 and Foxp3 may be useful biomarkers in patients with cervical cancer for predicting treatment.

Sex-determining region Y-related high mobility group box (SOX)-2 is overexpressed in cervical squamous cell carcinoma and contributes cervical cancer cell migration and invasion in vitro.

Sex-determining region Y-related high mobility group box 2 (SOX-2) is a key pluripotency-associated transcription factor and may be implicated in the pathogenesis of cervical squamous cell carcinoma (SCC). The aim of this study was to explore SOX-2 expression in cervical SCC tissues and to examine whether and how SOX-2 regulates the malignant behaviors of cervical SCC cells in vitro. We here found that SOX-2 expression in the examined cervical SCC tissues was higher than that in the normal cervical and cervical intraepithelial neoplasia (CIN) tissues. Higher protein level of SOX-2 (nuclear positive staining cells ≥50 %) was detected in 34.9 % (29 out of 83 cases) of cervical SCC patients. We also noted that 100 % of well-differentiated and 66.7 % of moderately differentiated cervical SCCs showed lower SOX-2 expression (nuclear positive staining cells <50 %), while 58.8 % of poorly differentiated tumors had higher SOX-2 expression (P < 0.05). Furthermore, the migratory and invasive capabilities of SiHa cervical cancer cells were enhanced when SOX-2 was upregulated whereas suppressed when SOX-2 was downregulated. Also, the phosphorylation levels of protein kinase B (Akt) and extracellular regulated protein kinases (ERK) 1/2 were increased in SOX-2-overexpressed cancer cells but decreased in SOX-2-depleted cells. Additionally, LY294002 (Akt pathway inhibitor) or U0126 (ERK pathway inhibitor) significantly suppressed SOX-2-overexpression-induced migration and invasion in SiHa cells. Our results indicate that differentially expressed SOX-2 is associated with tumor differentiation (P < 0.05) and that SOX-2 contributes to the migratory and invasive behaviors of cervical SCC in vitro.

Chemerin-induced mitochondrial dysfunction in skeletal muscle.

Chemerin is a novel adipocyte-derived factor that induces insulin resistance in skeletal muscle. However, the effect of chemerin on skeletal muscle mitochondrial function has received little attention. In the present study, we investigated whether mitochondrial dysfunction is involved in the pathogenesis of chemerin-mediated insulin resistance. In this study, we used recombinant adenovirus to express murine chemerin in C57BL/6 mice. The mitochondrial function and structure were evaluated in isolated soleus muscles from mice. The oxidative mechanism of mitochondrial dysfunction in cultured C2C12 myotubes exposed to recombinant chemerin was analysed by western blotting, immunofluorescence and quantitative real-time polymerase chain reaction. The overexpression of chemerin in mice reduced the muscle mitochondrial content and increased mitochondrial autophagy, as determined by the increased conversion of LC3-I to LC3-II and higher expression levels of Beclin1 and autophagy-related protein-5 and 7. The chemerin treatment of C2C12 myotubes increased the generation of mitochondrial reactive oxygen species, concomitant with a reduced mitochondrial membrane potential and increased the occurrence of mitochondrial protein carbonyls and mitochondrial DNA deletions. Knockdown of the expression of chemokine-like receptor 1 or the use of mitochondria-targeting antioxidant Mito-TEMPO restored the mitochondrial dysfunction induced by chemerin. Furthermore, chemerin exposure in C2C12 myotubes not only reduced the insulin-stimulated phosphorylation of protein kinase B (AKT) but also dephosphorylated forkhead box O3α (FoxO3α). Chemerin-induced mitochondrial autophagy likely through an AKT-FoxO3α-dependent signalling pathway. These findings provide direct evidence that chemerin may play an important role in regulating mitochondrial remodelling and function in skeletal muscle.

[Expression of Daxx and HPV16 E6 and its significance in cervical lesions].

OBJECTIVE: To investigate the expression of death domain associated protein (Daxx) and human papillomavirus 16 E6 protein (HPV16 E6) in cervical lesions and analyze their significance. METHODS: Immunohistochemical SABC method was used to detect the expression of Daxx and HPV16 E6 in 194 cases of cervical tissues with different lesions. RESULTS: (1) The positive expression rate of Daxx was 28.57% (12/42), 40.00% (18/45), 65.91% (29/44), 66.67% (42/63), respectively, in chronic cervicitis, cervical intraepithelial neoplasia I-II (CIN I-II), CIN III and cervical squamous cell carcinoma. The positive expression rate of HPV16 E6 was 15.38% (6/39), 36.17% (17/47), 46.30% (25/54), 100.00% (24/24) in the above four groups. The positive rates in cervical cancer group and high grade CIN group were significantly higher than these in low level of CIN group and chronic cervicitis group (P<0.05). (2) The expression of Daxx was stronger in HPV16 E6 high positive group than that in HPV16 E6 low positive group (P<0.05). (3) There was no significant relationship between the expression of Daxx and pathological classification, clinical stage, situation of lymph node metastasis or patients' age in cervical squamous cell carcinoma (P>0.05). (4) There was significant positive relationship between Daxx and HPV16 E6 expression (r=0.695, P<0.05). CONCLUSIONS: The expression of Daxx and HPV16 E6 gradually increases with cervical lesion degree aggravating. Here might be synergy between them, and both could promote the development of cervical lesions.

Expression and effects of high-mobility group box 1 in cervical cancer.

We investigated the significance of high- mobility group box1 (HMGB1) and T-cell-mediated immunity and prognostic value in cervical cancer. HMGB1, forkhead/winged helix transcription factor p3 (Foxp3), IL-2, and IL-10 protein expression was analyzed in 100 cervical tissue samples including cervical cancer, cervical intraepithelial neoplasia (CIN), and healthy control samples using immunohistochemistry. Serum squamous cell carcinoma antigen (SCC-Ag) was immunoradiometrically measured in 32 serum samples from 37 cases of squamous cervical cancer. HMGB1 and SCC-Ag were then correlated to clinicopathological characteristics. HMGB1 expression tends to increase as cervical cancer progresses and it was found to be significantly correlated to FIGO stage and lymph node metastasis. These findings suggest that HMGB1 may be a useful prognostic indicator of cervical carcinoma. In addition, there were significant positive relationships between HMGB1 and FOXP3 or IL-10 expression (both p<0.05). In contrast, HMGB1 and IL-2 expression was negatively correlated (p<0.05). HMGB1 expression may activate Tregs or facilitate Th2 polarization to promote immune evasion of cervical cancer. Elevated HMGB1 protein in cervical carcinoma samples was associated with a high recurrence of HPV infection in univariate analysis (p<0.05). HMGB1 expression and levels of SCC-Ag were directly correlated in SCC (p<0.05). Thus, HMGB1 may be a useful biomarker for patient prognosis and cervical cancer prediction and treatment.

Ginsenoside Rg3 improves cardiac mitochondrial population quality: mimetic exercise training.

Emerging evidence indicates exercise training could mediate mitochondrial quality control through the improvement of mitochondrial dynamics. Ginsenoside Rg3 (Rg3), one of the active ingredients in Panax ginseng, is well known in herbal medicine as a tonic and restorative agent. However, the molecular mechanism underlying the beneficial effects of Rg3 has been elusive. In the present study, we compared the effects of Rg3 administration with aerobic exercise on mitochondrial adaptation in cardiac muscle tissue of Sprague-Dawley (SD) rats. Three groups of SD rats were studied: (1) sedentary control, (2) Rg3-treated and (3) aerobic exercise trained. Both aerobic exercise training and Rg3 supplementation enhanced peroxisome proliferator-activated receptor coactivator 1 alpha (PGC-1α) and nuclear factor-E2-related factor 2 (Nrf2) protein levels in cardiac muscle. The activation of PGC-1α led to increased mRNA levels of mitochondrial transcription factor A (Tfam) and nuclear related factor 1(Nrf1), these changes were accompanied by increases in mitochondrial DNA copy number and complex protein levels, while activation of Nrf2 increased levels of phase II detoxifying enzymes, including nicotinamide adenine dinucleotide phosphate:quinone oxidoreductase 1(NQO1), superoxide dismutase (MnSOD) and catalase. Aerobic exercise also enhanced mitochondrial autophagy pathway activity, including increased conversion of LC3-I to LC3-II and greater expression of beclin1 and autophagy-related protein 7 (ATG7), these effects of aerobic exercise are comparable to that of Rg3. These results demonstrate that Rg3 mimics improved cardiac adaptations to exercise by regulating mitochondria dynamic remodeling and enhancing the quantity and quality of mitochondria.

Nebivolol stimulates mitochondrial biogenesis in 3T3-L1 adipocytes.

Nebivolol is a third-generation ß-adrenergic receptor (ß-AR) blocker with additional beneficial effects, including the improvement of lipid and glucose metabolism in obese individuals. However, the underlying mechanism of nebivolol's role in regulating the lipid profile remains largely unknown. In this study, we investigated the role of nebivolol in mitochondrial biogenesis in 3T3-L1 adipocytes. Exposure of 3T3-L1 cells to nebivolol for 24h increased mitochondrial DNA copy number, mitochondrial protein levels and the expression of transcription factors involved in mitochondrial biogenesis, including PPAR-γ coactivator-1α (PGC-1α), Sirtuin 3 (Sirt3), mitochondrial transcription factor A (Tfam) and nuclear related factor 1 (Nrf1). These changes were accompanied by an increase in oxygen consumption and in the expression of genes involved in fatty acid oxidation and antioxidant enzymes in 3T3-L1 adipocytes, including nebivolol-induced endothelial nitric oxide synthase (eNOS), as well as an increase in the formation of cyclic guanosine monophosphate (cGMP). Pretreatment with NG-nitro-L-arginine methyl ester (L-NAME) attenuated nebivolol-induced mitochondrial biogenesis, as did the soluble guanylate cyclase inhibitor, ODQ. Treatment with nebivolol and ß3-AR blocker SR59230A markedly attenuated PGC-1α, Sirt3 and manganese superoxide dismutase (MnSOD) protein levels in comparison to treatment with nebivolol alone. These data indicate that the mitochondrial synthesis and metabolism in adipocytes that is promoted by nebivolol is primarily mediated through the eNOS/cGMP-dependent pathway and is initiated by the activation of ß3-AR receptors.

[Progress in researches on active constituents and molluscicidal activity of Sapium sebiferum].

Sapium sebiferum contains a variety of organic acids, flavonoids and phenolic substances, which were linked with the functions of poisoning Oncomelania. Sapium sebiferum is a good plant material of inhibiting Oncomelania. This paper reviews the variety, resources and active ingredients of Sapium sebiferum, and the researches of Sapium sebiferum inhibiting Oncomelania, and forecasts the development of Sapium sebiferum as an inhibiting Oncomelania forest in order to provide the evidence for its penetrating research and development.

[Association of the MspI polymorphism of cytochrome P4501A1 gene and smoking to the susceptibility to coronary artery disease].

OBJECTIVE: To investigate the association of MspI polymorphism of Cytochrome P4501A1 (CYP1A1) gene and smoking to the susceptibility to coronary artery disease (CAD). METHODS: The genotypes of CYP1A1 MspI site were detected using the methods of polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 349 cases with CAD and 404 non-CAD as controls. CAD diagnosis was confirmed by coronary angiograms. Genetic risk of CYP1A1 genotypes was analyzed by smoking index (SI). RESULTS: The frequency of the predominant homozygotes TT, heterozygotes TC and the rare homozygotes CC in CAD group were not different with that of the controls (chi(2) = 3.224, P = 0.200). But in the smokers, the frequency of CC in CAD group was higher than that of non-CAD group (P = 0.002), while its odds ratio was 3.142 [95% confidence interval (CI) 1.481 - 6.668]. The odds ratio of genotype CC and heterozygote TC was 2.215 (95% CI 1.087 - 4.510) in the low dose cigarette smoking group, and was 1.407 (95% CI 0.709 - 2.791) in the high dose cigarette smoking group. CONCLUSION: Both MspI polymorphism of CYP1A1 gene and smoking exposure promote the development of CAD.

[Dynamic characters of sulphur and heavy metals concentrations in Pinus taiwanensis growth rings].

Based on the concentration analyses of S, Mn, Fe, Zn, Cu and Pb in the growth ring set of Pinus taiwanensis at the summit (1,400-1,600 m alt.) of Huangshan Mountains during past 80 years, this paper studied the dynamic characters of element concentrations in the ring set, and their relationships with atmospheric environment. The results showed that there were three levels of S concentration in the growth ring set, i.e., low concentration (less than 2 mg.kg(-1)), accounted for 58.5% of the ring set; medium (3.65-6.0 mg.kg(-1)), accounted for 24.4%; and high ( > 11.0 mg.kg(-1)), accounted for 17.1%. The dynamic change of S accumulation in the ring set displayed an obvious fluctuation, which could be divided into 3 major types, i.e., fluctuation during 1917-1960, relatively stable during 1961-1980, and gradual increase after 1981. In the growth ring set of 1935-1938, 1959-1960, and recent 10 years, the S accumulation concentrations were all higher than 11 mg.kg(-1), suggesting the relatively high atmospheric S concentration in those periods. There was a significant correlation between the increase of tourist amount in Huangshan scenic spot and the S concentration in growth ring set. The fuel fume centralized in some places might result in the atmospheric pollution at local scale, which in turn, might influence the S accumulation in growth ring set. The Pb accumulation concentration in the ring set was less than the background value in soil. The accumulation concentrations of Mn, Fe, Zn and Cu showed fluctuation characteristics, with independence of each other. The accumulation of Zn and Cu in growth rings had no correlation with tree age, while that of Mn and Fe was in adverse. The Mn concentration in the growth ring set decreased with tree age but increased in recent growth rings, while the Fe concentration was on the contrary, which needed further study.