Protective Effect of Combined Metoprolol and Atractylenolide I in Rats with Acute Myocardial Infarction via Modulation of the SIRT3/ß-CATENIN/PPAR-γ Signaling Pathway

ABSTRACT Herein, we examined the protective effect of metoprolol combined with atractylenolide I (Atr I) in acute myocardial infarction (AMI) by regulating the SIRT3 (silent information regulator 3)/ß-catenin/peroxisome proliferator-activated receptor gamma (PPAR-γ) signaling pathway. Briefly, 50 rats were randomly divided into the sham operation, model, metoprolol, Atr I, and combination metoprolol with Atr I groups (combined treatment group). The AMI model was established by ligating the left anterior descending coronary artery. After treatment, infarct size, histopathological changes, and cell apoptosis were examined using 2,3,5-triphenyltetrazolium chloride staining, hematoxylin-eosin staining, and the TUNEL assay. The left ventricular ejection fraction (LVEF), left ventricular fraction shortening (LVFS), and left ventricular mass index (LVMI) were detected by echocardiography. Endothelin-1 (ET-1), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6) levels were detected using enzyme-linked immunosorbent assays. Furthermore, we measured lactate dehydrogenase (LDH), creatine kinase (CK) isoenzyme (CK-MB), and CK levels. Western blotting was performed to determine the expression of SIRT3, ß-catenin, and PPAR-γ. Herein, the combined treatment group exhibited increased levels of LVEF, LVFS, and NO, whereas LVMI, ET-1, TNF-α, IL-6, LDH, CK-MB, and CK levels were decreased. Importantly, the underlying mechanism may afford protection against AMI by increasing the expression levels of SIRT3, ß-catenin, and PPAR-γ

Cigarette Smoke Induces Gefitinib Resistance in NSCLC Cells via ROS/Sirt3/SOD2 Pathway / 中国肺癌杂志

BACKGROUND@#Epidermal growth factor receptor (EGFR) gene mutations are the most common driver mutations in non-small cell lung cancer (NSCLC). To prolong the survival of the patients, EGFR tyrosine kinase inhibitors (TKIs) resistance in NSCLC is a major challenge that needs to be addressed urgently, and this study focuses on investigating the mechanism of cigarette smoke (CS) induced Gefitinib resistance in NSCLC.@*METHODS@#PC-9 and A549 cells were cultured in vitro and treated with 1 µmol/L Gefitinib for 4 h and 10% cigarette smoke extract (CSE) for 48 h. Western blot was used to detect Sirtuin 3 (Sirt3) and superoxide dismutase 2 (SOD2) protein expressions; DCFH-DA probe was used to detect intracellular reactive oxygen species (ROS); CCK-8 kit was used to detect cell activity, and EdU was used to detect cell proliferation ability. Sirt3 overexpression plasmid (OV-Sirt3) was transfected in PC-9 and A549 cells and treated with 1 µmol/L Gefitinib for 4 h and 10% CSE for 48 h after N-acetylcysteine (NAC) action. The expressions of Sirt3 and SOD2 were detected by Western blot; the ROS level in the cells was detected by DCFH-DA probe, and the cell activity was detected by CCK-8.@*RESULTS@#CSE induced an increase in the 50% inhibitory concentration (IC50) of both PC-9 and A549 cells to Gefitinib (P<0.01) and enhanced the proliferation of PC-9 and A549 cells, suggesting that CS induced Gefitinib resistance in NSCLC. ROS was involved in CSE-induced Gefitinib resistance (P<0.05). CSE induced low expressions of Sirt3 and SOD2 (P<0.01), and Sirt3/SOD2 was associated with poor prognosis in lung cancer patients (P<0.05). OV-Sirt3 in PC-9 and A549 cells reversed CSE-induced Gefitinib resistance (P<0.05) and significantly reduced ROS production. NAC reversed CSE-induced Gefitinib resistance in PC-9 and A549 cells (P<0.05).@*CONCLUSIONS@#The ROS/Sirt3/SOD2 pathway is involved in CS-induced Gefitinib resistance in NSCLC.

Progress on mitochondrial silence information regulator family in epilepsy / 浙江大学学报·医学版

SIRT3, SIRT4 and SIRT5 are located in mitochondria and also known as mitochondrial sirtuins. They play important roles in regulating many cellular functions including cell survival, cell cycle or apoptosis, DNA repair and metabolism. Mitochondrial sirtuins are involved in the protection of mitochondrial integrity and energy metabolism under stress regulating the expression of neurotransmitter receptors, neurotrophins, extracellular matrix proteins and various transcription factors, thus involved in epileptogenesis triggered by both genetic or acquired factors. Here we review research progress on the actions of mitochondrial sirtuin in epilepsy; and discuss the challenges and perspectives of mitochondrial sirtuin as a potential therapeutic target for epilepsy.

Acute cerebral ischemia-induced down-regulation of Sirt3 protein expression contributes to neuronal injury via damaging mitochondrial function / 生理学报

This study was aimed to determine the effect of acute cerebral ischemia on the protein expression level of silent mating type information regulator 2 homolog 3 (Sirt3) in the neurons and clarify the pathological role of Sirt3 in acute cerebral ischemia. The mice with middle cerebral artery occlusion (MCAO) and primary cultured rat hippocampal neurons with oxygen glucose deprivation (OGD) were used as acute cerebral ischemia models in vivo and in vitro, respectively. Sirt3 overexpression was induced in rat hippocampal neurons by lentivirus transfection. Western blot was utilized to measure the changes in Sirt3 protein expression level. CCK8 assay was used to detect cell viability. Immunofluorescent staining was used to detect mitochondrial function. Transmission electron microscope was used to detect mitochondrial autophagy. The results showed that, compared with the normoxia group, hippocampal neurons from OGD1 h/reoxygenation 2 h (R2 h) and OGD1 h/R12 h groups exhibited down-regulated Sirt3 protein expression levels. Compared with contralateral normal brain tissue, the ipsilateral penumbra region from MCAO1 h/reperfusion 24 h (R24 h) and MCAO1 h/R72 h groups exhibited down-regulated Sirt3 protein expression levels, while there was no significant difference between the Sirt3 protein levels on both sides of sham group. OGD1 h/R12 h treatment damaged mitochondrial function, activated mitochondrial autophagy and reduced cell viability in hippocampal neurons, whereas Sirt3 over-expression attenuated the above damage effects of OGD1 h/R12 h treatment. These results suggest that acute cerebral ischemia results in a decrease in Sirt3 protein level. Sirt3 overexpression can alleviate acute cerebral ischemia-induced neural injuries by improving the mitochondrial function. The current study sheds light on a novel strategy against neural injuries caused by acute cerebral ischemia.

Combatiendo el metabolismo de las células cancerosas mediante la activación de SIRT3 y el ejercicio físico / Combating tumor cells through SIRT3 activation and exercise

One of the main features of cancer is the high rate of cell proliferation and growth. To do this, cancer cells need to redirect their metabolism mainly towards anaerobic glycolysis and an increased mitochondrial glutamine energy metabolism. Sirtuins are cellular proteins with regulatory functions on metabolic pathways, genomic stability, apoptosis, longevity, inflammation, energy metabolism and oxidative stress. Sirtuins have emerged recently as a potential therapeutic option to treat several chronic diseases including cancer. This review summarizes the tumor suppressor function of Sirtuin 3 (SIRT3), highlighting its repressor effect on glycolytic metabolism, promoting mitochondrial metabolism and oxidative stress reduction. SIRT3 activation by exercise is particularly described since it may represent a potent tool for several types of cancer treatment.

Honokiol attenuates lipopolysaccharide-induced acute respiratory distress syndrome via activation of mitochondrion-dependent Sirt3/AMPK pathway / 中南大学学报(医学版)

To explore the effects of honokiol (HKL) on pulmonary microvascular endothelial cells in lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) and the underlying mechanisms.
 Methods: In animal experiment, a total of 40 C57BL/6J mice were randomly divided into a control group (Con group), a LPS intervention group (LPS group), a LPS+honokiol (HKL) intervention group (HKL group) and a LPS+HKL+nicotinamide (NAM) intervention group (NAM group) (n=10 in each group). In the cell experiment, the experiment cells were divided into a control group (Con group), a LPS intervention group (LPS group), a LPS+HKL intervention group (HKL group), a LPS+HKL+NAM intervention group (NAM group), and a LPS+HKL+compound C (CMC) intervention group (CMC group). The pathological changes of the lung tissues were evaluated by hematoxylin and eosin (HE) staining; the protein concentration, total cells and neutrophils in the bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) activity in the lung tissues were detected; the changes of pulmonary microvascular permeability were determined by Evans blue assay; the effect of HKL on the vitality of human pulmonary microvascular endothelial cells were examined by cell counting kit-8 (CCK-8); the inhibitors including NAM and CMC were applied to explore the molecular mechanism of the protective effects of HKL. The expression levels of Sirt3, caspase-3, cleaved caspase-3, Bcl-2, Bax, p-adenosine monophosphate activated protein kinase (p-AMPK) and AMPK in lung tissues or cells were detected by Western blot.
 Results: In animal models, compared with the Con group, the mice in the LPS group displayed typical ARDS pathological changes, and the ratio of lung wet/dry weight (W/D) and MPO activity in the lung tissues, protein concentration, total cells and neutrophils in BALF, Evans blue leaking index (ELI), expression levels of cleaved caspase-3 were significantly increased (all P<0.05), while the expression levels of Sirt3 was obviously decreased (P<0.05). Compared with the LPS group, the above changes in the LPS group were significantly improved in the HKL group (all P<0.05); Compared with the HKL group, the curative effect of HKL intervention could be partly inhibited in the NAM group (P<0.05). In cell experiments, compared with the LPS group, the HPMECs viability in the HKL group was markedly improved (P<0.05), while the expression levels of Bcl-2 and Sirt3 were significantly upregulated (P<0.05), and the expression levels of Bax and cleaved caspase-3 were significantly downregulated (P<0.05), accompanied by the activation of AMPK pathway (P<0.05) in the HKL group. Compared with the HKL group, the curative effect of HKL intervention was partly inhibited in the CMC group (P<0.05).
 Conclusion: HKL can significantly attenuate LPS-induced lung injury and inhibit the apoptosis of pulmonary microvascular endothelial cells through regulation of Sirt3/AMPK pathway.

Role of SIRT3 in regulating proliferation of hepatocellular carcinoma cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the role of SIRT3 in regulating the proliferation of hepatocellular carcinoma (HCC) cells in vitro.</p><p><b>METHODS</b>The protein expression of SIRT3 in 2 normal liver tissues, 2 immortalized hepatocyte lines, and 3 HCC cell lines was determined with Western blotting. SIRT3 overexpression and knockdown in HCC cells were induced by transfection with a vector expressing SIRT3 and a siRNA construct targeting SIRT3, respectively. The efficiency of SIRT3 overexpression and knockdown was detected by Western blot and qRT-PCR, respectively. The proliferation of the transfected HCC cells was examined using Trypan blue exclusion assay, and the cellular DNA synthesis was tested using EdU incorporation assay. The colony-forming ability of the cells was analyzed by colony formation assays.</p><p><b>RESULTS</b>SIRT3 expression was significantly lower in the 3 HCC cell lines than in immortalized hepatocytes and normal liver tissues. SIRT3 overexpression in HCC cells significantly lowered the cell proliferation by 51%-61% (P<0.001), reduced cellular DNA synthesis by 57% (P<0.05), and inhibited colony formation of the cells. SIRT3 knockdown significantly increased the proliferation of HCC cells by 51%-61% (P<0.01) and enhanced DNA synthesis by 137%-149% (P<0.01).</p><p><b>CONCLUSIONS</b>SIRT3 plays a inhibitory role in regulating the proliferation of HCC cells in vitro.</p>

Poly(ADP-ribose) polymerase 1 contributes to oxidative stress through downregulation of sirtuin 3 during cisplatin nephrotoxicity / 대한해부학회지

Enhanced oxidative stress is a hallmark of cisplatin nephrotoxicity, and inhibition of poly(ADP-ribose) polymerase 1 (PARP1) attenuates oxidative stress during cisplatin nephrotoxicity; however, the precise mechanisms behind its action remain elusive. Here, using an in vitro model of cisplatin-induced injury to human kidney proximal tubular cells, we demonstrated that the protective effect of PARP1 inhibition on oxidative stress is associated with sirtuin 3 (SIRT3) activation. Exposure to 400 µM cisplatin for 8 hours in cells decreased activity and expression of manganese superoxide dismutase (MnSOD), catalase, glutathione peroxidase (GPX), and SIRT3, while it increased their lysine acetylation. However, treatment with 1 µM PJ34 hydrochloride, a potent PARP1 inhibitor, restored activity and/or expression in those antioxidant enzymes, decreased lysine acetylation of those enzymes, and improved SIRT3 expression and activity in the cisplatin-injured cells. Using transfection with SIRT3 double nickase plasmids, SIRT3-deficient cells given cisplatin did not show the ameliorable effect of PARP1 inhibition on lysine acetylation and activity of antioxidant enzymes, including MnSOD, catalase and GPX. Furthermore, SIRT3 deficiency in cisplatin-injured cells prevented PARP1 inhibition-induced increase in forkhead box O3a transcriptional activity, and upregulation of MnSOD and catalase. Finally, loss of SIRT3 in cisplatin-exposed cells removed the protective effect of PARP1 inhibition against oxidative stress, represented by the concentration of lipid hydroperoxide and 8-hydroxy-2'-deoxyguanosine; and necrotic cell death represented by a percentage of propidium iodide–positively stained cells. Taken together, these results indicate that PARP1 inhibition protects kidney proximal tubular cells against oxidative stress through SIRT3 activation during cisplatin nephrotoxicity.

Green Tea Polyphenols Attenuate High-Fat Diet-Induced Renal Oxidative Stress through SIRT3-Dependent Deacetylation / 生物医学与环境科学（英文）

Fifty male Wistar rats were fed a standard chow diet or a high-fat (HF) diet, and different concentrations of green tea polyphenols (GTPs) (0.8, 1.6, and 3.2 g/L) were administered in the drinking water. We found that the malondialdehyde (MDA) level in the HF diet group was significantly higher than that in the control (CON) group (P<0.05). Decreased peroxisome proliferator-activated receptor (PPAR)-α and sirtuin 3 (SIRT3) expression, and increased manganese superoxide dismutase (MnSOD) acetylation levels were also detected in the HF diet group (P<0.05). GTP treatment upregulated SIRT3 and PPARα expression, increased the pparα mRNA level, reduced the MnSOD acetylation level, and decreased MDA production in rats fed a HF diet (P<0.05). No significant differences in total renal MnSOD and PPAR-γ coactivator-1α (PGC1-α) expression were detected. The reduced oxidative stress detected in kidney tissues after GTP treatment was partly due to the higher SIRT3 expression, which was likely mediated by PPARα.

Metformin ameliorates insulin resistance in L6 rat skeletal muscle cells through upregulation of SIRT3 / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>SIRT3 is an important regulator in cell metabolism, and recent studies have shown that it may be involved in the pharmacological effects of metformin. However, the molecular mechanisms underlying this process are unclear.</p><p><b>METHODS</b>The effects of SIRT3 on the regulation of oxidative stress and insulin resistance in skeletal muscle were evaluated in vitro. Differentiated L6 skeletal muscle cells were treated with 750 µmol/L palmitic acid to induce insulin resistance. SIRT3 was knocked down and overexpressed in L6 cells. SIRT3, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65, c-Jun N-terminal kinase 1 (JNK1), and superoxide dismutase 2 (SOD2) were evaluated by Western blotting.</p><p><b>RESULTS</b>Over expression of SIRT3 increased glucose uptake and decreased ROS production in L6-IR cells as well as in L6 cells. Knock-down of SIRT3 induced increased production of ROS while decreased glucose uptake in both L6 and L6-IR cells, and these effects were reversed by N-acetyl-L-cysteine (NAC). Metformin increased the expression of SIRT3 (1.5-fold) and SOD2 (2-fold) while down regulating NF-κB p65 (1.5-fold) and JNK1 (1.5-fold). Knockdown of SIRT3 (P < 0.05) reversed the metformin-induced decreases in NF-κB p65 and JNK1 and the metformin-induced increase in SOD2 (P < 0.05).</p><p><b>CONCLUSIONS</b>Upregulated SIRT3 is involved in the pharmacological mechanism by which metformin promotes glucose uptake. Additionally, SIRT3 may function as an important regulator of oxidative stress and a new alternative approach for targeting insulin resistance-related diseases.</p>

Effects of long-term sleep deprivation on mitochondria stress in locus coeruleus and the tyrosine hydroxylasic projection in mice / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To observe the changes of mitochondria stress in locus coeruleus and the tyrosine hydroxylasic projection after long-term sleep deprivation.</p><p><b>METHODS</b>Sleep deprivation mice model was set up by employing "novel environments" method. The expression of NAD -dependent deacetylase Sirtuin type 3 (SIRT3), which regulates mitochondrial energy production and oxidative stress, and heat shock protein 60 (HSP60), a major biomarker of mitochondrial stress, and the tyrosine hydroxylasic projection from locus coeruleus were analyzed after a 5-day sleep deprivation.</p><p><b>RESULTS</b>Compared to the control group, the expression of SIRT3 in locus coeruleus was significantly decreased in respouse to long-term sleep deprivation, while the expression of HSP60 was significantly increased. In addition, relative to control group, pereentage area of the tyrosine hydroxylasic projection to anterior cingulate cortex was substantial decreased in long-term sleep deprivation group.</p><p><b>CONCLUSION</b>Long-term sleep deprivation induced the decreased level of SIRT3 expression and the elevation of mitochondrial stress in locus coenileus, which may further lead to the loss of tyrosine hydroxylasic projection in mice.</p>

SIRT3 expression in hepatocellular carcinoma and its impact on proliferation and invasion of hepatoma cells

OBJECTIVE@#To observe expression of SIRT3 in normal liver tissue, cirrhotic tissue and hepatocellular carcinoma (HCC) tissues, and to explore the significance of SIRT3 in primary HCC.@*METHODS@#SIRT3 expression was detected in 10 normal cases, 30 cases with, 30 HCC cases by immunohistochemical and Western-blotting method.@*RESULTS@#Immunohistochemical assay showed that the SIRT3 positive expression rates were 100.0% (10/10), 96.7% (29/30) and 60.0% (18/30), respectively in normal group, paracancer group and HCC group. And the SIRT3 expression in HCC group was significantly lower than in normal group and paracancer group (P<0.05). Western-blotting showed the SIRT3 expression in cancer tissue was 0.29±0.07, significantly lower than that in paracancer group and normal group (P<0.05). SIRT3 expression was related to the differentiation degree and portal vein tumor thrombus (P<0.05).@*CONCLUSIONS@#Abnormal expression of SIRT3 is closely related to the biological behavior of primary HCC.