Lycium barbarum polysaccharides regulate AMPK/Sirt autophagy pathway to delay D-gal-induced premature ovarian failure / 中国中药杂志

This study aims to explore the molecular mechanism of Lycium barbarum polysaccharides(LBP) in alleviating premature ovarian failure(POF) in mice via the 5'-adenosine monophosphate activated protein kinase(AMPK)/silent information regulator 1(Sirt1) signaling pathway. The POF mouse model was established by D-galactose(D-gal) injection at the back. Six groups were set up, including a normal control group, a model group, a LBP group, a 3-MA(autophagy inhibitor 3-methyladenine) group, an AMPK inhibitor group, and a LBPAMPK inhibitor group, with 15 mice in each group. After 28 continuous days of administration, enzyme-linked immunosorbent assay(ELISA) was employed to determine the levels of sex hormones [estradiol(E_2), luteinizing hormone(LH), and follicle-stimulating hormone(FSH)] in serum. The ovarian mass coefficient was measured. Senescence-associated β-Galactosidase(SA-β-Gal) staining and hematoxylin-eosin(HE) staining were performed for observing the state of ovarian senescence and the morphological changes of the ovary. Immunohistochemical method was used to measure the expression of the autophagy marker LC3-Ⅱ in ovarian tissue. Western blot was employed to measure the expression levels of the senescence marker p16~(INK4 a), autophagy markers(LC3-Ⅱ and Beclin-1), the autophagy substrate p62, lysosome-associated membrane protein 2(LAMP2), and the proteins in the AMPK/Sirt1 pathway and mammalian target of rapamycin complex 1(mTORC1)/UNC-51-like kinase 1 Ser757 site(Ulk1 Ser757) pathway. Compared with the normal control group, the modeling of POF decreased the ovarian granulosa cells and follicles, led to the ovarian aging and severe sex hormone secretion disorders, weakened ovarian autophagy activity, and down-regulated the expression of proteins in the AMPK/Sirt1 pathway(P<0.05). Compared with the model group, the treatment with LBP increased ovarian granulosa cells and follicles, alleviated aging and sex hormone disorders, increased autophagy activity, and activated the AMPK/Sirt1 pathway(P<0.05). Both 3-MA and AMPK inhibitor can inhibit autophagy and aggravate ovarian damage and aging in mice. AMPK inhibitor can partially attenuate the role of LBP in promoting autophagy activation and alleviating aging and ovarian tissue damage(P<0.05). LBP can alleviate the symptoms of POF induced by D-gal by promoting the activation of AMPK/Sirt1 pathway.

Perfluorooctanoic acid-induced lipid metabolism disorder in SD rat liver and its effect on the expression of fatty acid metabolism-related proteins / 中南大学学报(医学版)

OBJECTIVES@#Perfluorooctanoic acid (PFOA) can cause lipid metabolism disorders in animal body and affect the lipolysis and synthesis of fatty acids. Peroxisome proliferators-activated receptor (PPAR) plays an extremely important role in this process. This study aims to explore the effects of PFOA on liver lipid metabolism disorders in Sprague Dewley (SD) rats and the expression of PPAR.@*METHODS@#A total of 40 male SD rats were randomly divided into 4 groups (n=10 in each group): a control group (ddH2O), a low-dose PFOA group [PFOA 1.25 mg/(kg·d)], a middle-dose PFOA group [PFOA 5.00 mg/(kg·d)], and a high-dose PFOA group [PFOA 20.00 mg/(kg·d)]. The rats were fed with normal diet, and PFOA exposure were performed by oral gavage for 14 days, and the rats were observed, weighted and recorded every day during the exposure. After the exposure, the blood was collected, and the livers were quickly stripped after the rats were killed. Part of the liver tissues were fixed in 4% paraformaldehyde for periodic acid-schiff (PAS) staining; the contents of HDLC, LDLC, TG, TC in serum and liver tissues, as well as the activities of their related enzymes were assayed; The expression levels of cyclic adenosine monophosphate-response element binding protein (Cbp), general control of amino acid synthesis 5-like 2 (Gcn5L2), peroxidation peroxisome proliferation factor activated receptor γ (PPAR), silent information regulator 1 (Sirt1) and human retinoid X receptor alpha 2 (Rxrα2) ) were detected by Western blotting.@*RESULTS@#After 14 days of PFOA exposure, the PAS staining positive particles in the cytoplasm and nucleus of SD rats in the medium and high dose groups were significantly reduced compared with the control group. The serum levels of LDLC and TC in the low-dose and middle-dose groups were significantly reduced compared with the control group (all P<0.05), while the high-dose group showed an increasing tendency, without siginificant difference (P>0.05), there was no significant difference in HDLC and TG (both P>0.05). The activities of alkaline phosphatase (AKP) and alanine aminotransferase (ALT) were increased significantly (both P<0.05) compared with control group; the ratio of ALT/aspartate aminotransferase (AST) in the high-dose group was increased significantly (P<0.05), there was no significant difference in LDH and TG (both P>0.05); the HDLC content in the liver tissues in the high-dose group was significantly reduced, compared with the control group (P<0.05); the TC contents in the liver tissues in the low, medium and high-dose groups were significantly increased (all P<0.05), there was no significant difference in LDLC and TG (both P>0.05); the AKP activity in the livers in the medium and high-dose groups was significantly increased (both P<0.05), there was no siginificant difference in LDH, ALT, and the ratio of ALT/AST (all P>0.05); the protein expression levels of Ppar γ, Cbp and Rxrα2 in the liver in the high dose groups were significantly down-regulated compared with the control group (all P<0.05), while the protein expression levels of Sirt1 were significantly up-regulated (all P<0.05).@*CONCLUSIONS@#PFOA exposure can cause lipid metabolism disorder and glycogen reduction in SD rat livers, which may be related to the activation of Sirt1 and inhibition of Ppar γ expression, leading to affecting the normal metabolism of fatty acids and promoting glycolysis.

Study on the Protective effect and mechanism of Nicotinamide Riboside on lung injury in paraquat intoxicated mice / 中华劳动卫生职业病杂志

Objective: To investigate the protective effect and mechanism of Nicotinamide Riboside (NR) on lung injury caused by Paraquat intoxicated mice. Methods: Eighty clean male BALB/C mice were selected and averagely divided forty mice into 4 groups with 10 mice in each group, PQ group was given 25% PQ solution (60 mg/kg) by one-time gavage. PQ+NR group were intraperitoneally injected with NR solution (300 mg/kg) 1 hour before given the same amount of PQ solution (60 mg/kg) by one-time gavage, The Control group were given the same amount of saline by one-time gavage, The same amount of NR was intraperitoneally injected before NR group were given saline by one-time gavage. Observed and recorded general condition of PQ intoxicated mice. Observed and recorded the death of mice every half an hour and counted the mortality and drew survival curve of each group after 72 hours exposure. another forty mice were averagely divided and treated by the same way. After 24 hours of modelling, mice were anaesthetized and killed. Then blood was extracted after eyeball was removed. The changes of TNF-a、IL-6 and MPO in serum of mice were detected by ELISA.Two lung tissues were removed from the chest and used to measure the D/W ratio of the lung. The pathological changes of lung were observed and scored under light microscope.The levels of SOD, MDA and Caspase-3 in lung tissues were determined by chemical colorimetry. The expression of Sirt1 and Nrf2 in lung tissues was detected by Western-blot. Results: Compared with the Control group and the NR group, the mice in the PQ group had a poor general condition, such as depression, crouching, skin disorder and reduced activity, food, urine and feces. The symptoms in the PQ+NR group were reduced compared with the PQ group. The survival rate at 72 hours after exposure: 80% in the PQ+NR group and 40% higher than that in the PQ group (P=0.029) . Compared with Control group and NR group, the D/W ratio (0.09±0.07) , lung pathology score under light microscope (11.80±0.37) , TNF-a (39.89±1.48) pg/ml、IL-6 (77.29±2.38) pg/ml、MPO (0.31±0.01) μg/ml、SOD (6.62±0.30) U/mgprot、MDA level (1.21±0.14) mmol/mgprot, Caspase-3 activity (356.00± 27.16) %, Sirt1 and Nrf2 protein expression (1.02±0.14、0.82±0.06) were significantly decreased in PQ group (P=0.004、0.023) ; Compared with PQ group, PQ+NR group significantly increased the D/W ratio (0.10±0.10) , decreased the pulmonary pathology score under light microscope (7.400.51) , decreased TNF-a (33.00± 0.65) pg/ml、IL-6 (52.23±4.23) pg/ml、MPO leve (0.23±0.01) μg/mll, increased SOD leve (9.28±0.45) U/mgprotl, decreased MDA level (0.78±0.02) mmol/mgprot, decreased Caspase-3 activity (222.80±7.59) %, and increased the protein expressions of Sirt1 and Nrf2 (1.62±0.16、1.06±0.04) (P=0.048、0.035) . Conclusion: NR can prolong the survival time of PQ poisoned mice; NR intervention can effectively inhibit the inflammatory response, peroxidation injury and apoptosis of PQ poisoned mice; NR intervention can upregulate the expression of Sirt1 and Nrf2 protein and effectively reduce the lung injury of PQ poisoning.

Modulation of SIRT1 expression improves erectile function in aged rats / 亚洲男科学杂志(英文版)

Silent information regulator 2-related enzyme 1 (SIRT1) is an aging-related protein activated with aging. Herein, we evaluated the role of SIRT1 in aging-related erectile dysfunction. The expression of SIRT1 was modulated in aged Sprague-Dawley rats following intragastric administration of resveratrol (Res; 5 mg kg-1), niacinamide (NAM; 500 mg kg-1) or Res (5 mg kg-1) + tadalafil (Tad; phosphodiesterase-5 [PDE5] inhibitor; 5 mg kg-1) for 8 weeks. Then, we determined erectile function by the ratio of intracavernosal pressure (ICP)/mean systemic arterial pressure (MAP). Cavernosal tissues were extracted to evaluate histological changes, cell apoptosis, nitric oxide (NO)/cyclic guanosine monophosphate (cGMP), the superoxide dismutase (SOD)/3,4-methylenedioxyamphetamine (MDA) level, and the expression of SIRT1, p53, and forkhead box O3 (FOXO3a) using immunohistochemistry, terminal deoxynucleotidyl transferase (TdT)-mediated 2'-deoxyuridine 5'-triphosphate (dUTP) nick-end labeling (TUNEL), enzyme-linked immunosorbent assays, and western blot analysis. Compared with the control, Res treatment significantly improved erectile function, reflected by an increased content of smooth muscle and endothelium, NO/cGMP and SOD activity, and reduced cell apoptosis and MDA levels. The effect of Res was improved by adding Tad. In addition, the protein expression of SIRT1 was increased in the Res group, accompanied by decreased p53 and FOXO3a levels. In addition, inhibition of SIRT1 by NAM treatment resulted in adverse results compared with Res treatment. SIRT1 activation ameliorated aging-related erectile dysfunction, supporting the potential of SIRT1 as a target for erectile dysfunction treatment.

Wogonoside alleviates high glucose-induced dysfunction of retinal microvascular endothelial cells and diabetic retinopathy in rats by up-regulating SIRT1 / 南方医科大学学报

OBJECTIVE@#To investigate the effects of wogonoside on high glucose-induced dysfunction of human retinal microvascular endothelial cells (hRMECs) and streptozotocin (STZ)-induced diabetic retinopathy in rats and explore the underlying molecular mechanism.@*METHODS@#HRMECs in routine culture were treated with 25 mmol/L mannitol or exposed to high glucose (30 mmol/L glucose) and treatment with 10, 20, 30, 40 μmol/L wogonoside. CCK-8 assay and Transwell assay were used to examine cell proliferation and migration, and the changes in tube formation and monolayer cell membrane permeability were tested. ROS, NO and GSH-ST kits were used to evaluate oxidative stress levels in the cells. The expressions of IL-1β and IL-6 in the cells were examined with qRT-PCR and ELISA, and the protein expressions of VEGF, HIF-1α and SIRT1 were detected using Western blotting. We also tested the effect of wogonoside on retinal injury and expressions of HIF-1α, ROS, VEGF, TNF-α, IL-1β, IL-6 and SIRT1 proteins in rat models of STZ-induced diabetic retinopathy.@*RESULTS@#High glucose exposure caused abnormal proliferation and migration, promoted angiogenesis, increased membrane permeability (P < 0.05), and induced inflammation and oxidative stress in hRMECs (P < 0.05). Wogonoside treatment concentration-dependently inhibited high glucose-induced changes in hRMECs. High glucose exposure significantly lowered the expression of SIRT1 in hRMECs, which was partially reversed by wogonoside (30 μmol/L) treatment; interference of SIRT1 obviously attenuated the inhibitory effects of wogonoside against high glucose-induced changes in proliferation, migration, angiogenesis, membrane permeability, inflammation and oxidative stress in hRMECs. In rat models of STZ-induced diabetic retinopathy, wogonoside effectively suppressed retinal thickening (P < 0.05), alleviated STZ-induced retinal injury, and increased the expression of SIRT1 in the retinal tissues (P < 0.001).@*CONCLUSION@#Wogonoside alleviates retinal damage caused by diabetic retinopathy by up-regulating SIRT1 expression.

Polydatin improves intestinal barrier injury after traumatic brain injury in rats by reducing oxidative stress and inflammatory response via activating SIRT1-mediated deacetylation of SOD2 and HMGB1 / 南方医科大学学报

OBJECTIVE@#To investigate the protective effect against intestinal mucosal injury in rats following traumatic brain injury (TBI) and explore the underlying mechanism.@*METHODS@#SD rat models of TBI were established by fluid percussion injury (FPI), and the specimens were collected at 12, 24, 48, and 72 h after TBI. Another 15 rats were randomly divided into shamoperated group (n=5), TBI with saline treatment (TBI+NS) group (n=5), and TBI with PD treatment (TBI+PD) group (treated with 30 mg/kg PD after TBI; n=5). Body weight gain and fecal water content of the rats were recorded, and after the treatments, the histopathology of the jejunum was observed, and the levels of D-lactic acid (D-LAC), diamine oxidase (DAO), ZO-1, claudin-5, and reactive oxygen species (ROS) were detected. Lipid peroxide (LPO) and superoxide dismutase (SOD) 2 content, jejunal pro-inflammatory factors (IL-6, IL-1β, and TNF- α), Sirt1 activity, SOD2 and HMGB1 acetylation level were also determined after the treatments.@*RESULTS@#The rats showed significantly decreased body weight and fecal water content and progressively increased serum levels of D-LAC and DAO after TBI (P < 0.05) with obvious jejunal injury, significantly decreased expression levels of ZO-1 and claudin-5, lowered SOD2 and Sirt1 activity (P < 0.05), increased expression levels of LPO, ROS, and pro-inflammatory cytokines, and enhanced SOD2 and HMGB1 acetylation levels (P < 0.05). Compared with TBI+NS group, the rats in TBI+PD group showed obvious body weight regain, increased fecal water content, reduced jejunal pathologies, decreased D-LAC and DAO levels (P < 0.05), increased ZO-1, claudin-5, SOD2 expression levels and Sirt1 activity, and significantly decreased ROS, LPO, pro-inflammatory cytokines, and acetylation levels of SOD2 and HMGB1 (P < 0.05).@*CONCLUSION@#PD alleviates oxidative stress and inflammatory response by activating Sirt1-mediated deacetylation of SOD2 and HMGB1 to improve intestinal mucosal injury in TBI rats.

The role and mechanism of SIRT1 gene in depression / 生理学报

As a kind of mental illness, depression produces great difficulties in clinical diagnosis and treatment, and has a high disability rate. It is urgent to clarify the mechanism of depression to find potential therapeutic targets and effective clinical treatment methods. As a deacetylase, silent mating type information regulator 2 homolog 1 (SIRT1) is involved in many biological processes such as cell aging, cancer, and cardiovascular disease. In recent years, more and more studies have found that SIRT1 gene plays an important role in the pathogenesis of depression, but the mechanism is still unclear. Therefore, this review mainly summarizes the relevant research progress on the role and mechanism of SIRT1 gene in the hippocampus, prefrontal cortex, amygdala, hypothalamic suprachiasmatic nucleus, and nucleus accumbens in depression, in order to provide new ideas for exploring the mechanism and prevention of depression.

Inhibition of miR-383 suppresses oxidative stress and improves endothelial function by increasing sirtuin 1

Previous research has shown that suppression of miR-383 can prevent inflammation of the endothelium, as well as postpone the development of atherosclerosis. However, the role of miR-383 in endothelial cell apoptosis in diabetes remains unclear. The aim of this study was to investigate the function of miR-383 in high glucose-induced apoptosis and oxidative stress in endothelial cells. A series of experiments involving qualitative polymerase chain reaction, cell transfection, luciferase assay, assessment of cell death, detection of catalase and superoxide dismutase concentrations, detection of intracellular reactive oxygen species (ROS), and western blot analysis were performed in this study. We found that miR-383 expression was promoted, while NAD+-dependent deacetylase and sirtuin 1 (SIRT1) expressions were suppressed in the endothelium of the aorta in db/db mice as well as in human umbilical vein endothelial cells, which were treated with high glucose (HG). Increased expression of miR-383 decreased expression of SIRT1, while suppression of miR-383 promoted expression of SIRT1 in human umbilical vein endothelial cells (HUVECs). Furthermore, suppression of miR-383 following transfection with miR-383 suppressor repressed cell death and generation of ROS in HUVECs. SIRT1 knockdown by siRNA-SIRT1 reversed the suppressive effect of miR-383 inhibition on ROS production and cell apoptosis induced by HG treatment. Overall, the findings of our research suggested that suppression of miR-383 repressed oxidative stress and reinforced the activity of endothelial cells by upregulation of SIRT1 in db/db mice, and targeting miR-383 might be promising for effective treatment of diabetes.

Down-regulated miR-448 relieves spinal cord ischemia/reperfusion injury by up-regulating SIRT1

MicroRNAs play a crucial role in the progression of spinal cord ischemia/reperfusion injury (SCII). The role of miR-448 and SIRT1 in SCII was investigated in this study, to provide further insights into prevention and improvement of this disorder. In this study, expressions of miR-448 and SIRT1 protein were determined by qRT-PCR and western blot, respectively. Flow cytometry was used to analyze cell apoptosis. The endogenous expression of genes was modulated by recombinant plasmids and cell transfection. Dual-luciferase reporter assay was performed to determine the interaction between miR-448 and SIRT1. The Basso, Beattie, and Bresnahan score was used to measure the hind-limb function of rat. The spinal cord ischemia reperfusion injury model of adult rats was developed by abdominal aorta clamping, and the nerve function evaluation was completed by motor deficit index score. In SCII tissues and cells treated with hypoxia, miR-448 was up-regulated while SIRT1 was down-regulated. Hypoxia treatment reduced the expression of SIRT1 through up-regulating miR-448 in nerve cells. Up-regulation of miR-448 induced by hypoxia promoted apoptosis of nerve cells through down-regulating SIRT1. Down-regulated miR-448 improved neurological function and hind-limb motor function of rats with SCII by up-regulating SIRT1. Down-regulated miR-448 inhibited apoptosis of nerve cells and improved neurological function by up-regulating SIRT1, which contributes to relieving SCII.

miR-22 suppresses tumorigenesis and improves radiosensitivity of breast cancer cells by targeting Sirt1

BACKGROUND: miR-22 has been shown to be frequently downregulated and act as a tumor suppressor in multiple cancers including breast cancers. However, the role of miR-22 in regulating the radioresistance of breast cancer cells, as well as its underlying mechanism is still not well understood. METHODS: The expressions of miR-22 and sirt1 at mRNA and protein levels were examined by qRT-PCR and Western Blot. The effects of miR-22 overexpression and sirt1 knockdown on cell viability, apoptosis, radiosensitivity, γ-H2AX foci formation were evaluated by CCK-8 assay, flow cytometry, colony formation assay, and γ-H2AX foci formation assay, respectively. Luciferase reporter assay and qRT-PCR analysis were performed to confirm the interaction between miR-22 and sirt1. RESULTS: miR-22 was downregulated and sirt1 was upregulated at both mRNA and protein levels in breast cancer cells. miR-22 overexpression or sirt1 knockdown significantly suppressed viability, induced apoptosis, reduced survival fraction, and increased the number of γ-H2AX foci in breast cancer cells. Sirt1 was identified as a target of miR-22 and miR-22 negatively regulated sirt1 expression. Ectopic expression of sirt1 dramatically reversed the inhibitory effect of miR-22 on cell viability and promotive effect on apoptotic rates and radiosensitivity in breast cancer cells. CONCLUSIONS: miR-22 suppresses tumorigenesis and improves radiosensitivity of breast cancer cells by targeting sirt1, providing a promising therapeutic target for breast cancer.

Propuesta de reformas a los prestadores públicos de servicios médicos en Chile: “fortaleciendo la opción pública” / A reform proposal to strengthen public health care

Currently, there is no discussion on the need to improve and strengthen the institutional health care modality of FONASA (MAI), the health care system used by the public services net and by most of the population, despite the widely known and long lasting problems such as waiting lists, hospital debt with suppliers, lack of specialists and increasing services purchase transference to the private sector, etc. In a dichotomous sectorial context, such as the one of health’s social security in Chile (the state on one side and the market on the other), points of view are polarized and stances tend to seek refuge within themselves. As a consequence, to protect the public solution is commonly associated with protecting the “status quo”, creating an environment that is reluctant to change. The author proposes a solution based on three basic core ideas, which, if proven effective, can strengthen each other if combined properly. These are: network financing management, governance of health care services in MAI and investments and human resources in networked self-managed institutions. The proposal of these core ideas was done introducing a reality testing that minimizes the politic complexity of their implementation.