Silent Mating Type Information Regulation 2 Homolog-1 Research Articles

Febuxostat, a novel inhibitor of xanthine oxidase, reduces ER stress through upregulation of SIRT1-AMPK-HO-1/thioredoxin expression.

Endoplasmic reticulum (ER) stress has been implicated in the development of various renal diseases. Thus, inhibition of ER stress using pharmacological agents may serve as a promising therapeutic approach. We postulated that febuxostat, a novel xanthine oxidase inhibitor, could suppress the ER stress through upregulation of SIRT1 (silent mating type information regulation 2 homolog 1)-AMPK (AMP activated protein kinase)-HO-1 (heme oxygenase-1)/thioredoxin expression. We examined the effect of febuxostat on the ER stress induced by a chemical inducer, tunicamycin and non-chemical agents such as angiotensin II, aldosterone, high glucose, and albumin in renal tubular cells. We further examined the in vivo effects of febuxostat using mouse model of kidney disease induced by unilateral ureteral obstruction (UUO). Expression of ER stress was measured by western blot analysis and immunohistochemical stain. Febuxostat suppressed the ER stress induced by tunicamycin and non-chemical agents, as shown by inhibition of increased GRP78 (glucose-related protein78) and p-eIF2α (phosphospecific-eukaryotic translation initiation factor 2α) expression. Inhibitory effect of febuxostat was mediated through upregulation of SIRT1-AMPK followed by induction of HO-1 and thioredoxin. In animal model of UUO, febuxostat reduced the UUO-induced ER stress, which was abolished by pretreatment with SIRT1 inhibitor (sirtinol) and AMPK inhibitor (compound C). Febuxostat could suppress the ER stress caused by various ER stress inducers through upregulation of SIRT1-AMPK-HO-1/thioredoxin expression. Targeting these pathways might serve as one of the possible therapeutic approaches in kidney diseases under excessive ER stress.

S51RECALIBRATING THE EPIGENETIC CLOCK: APPLICATIONS FOR ASSESSING BIOLOGICAL AGEING IN THE HUMAN BRAIN

Experimental and epidemiological evidence reveal the profound influence that industrialized modern society has imposed on human social habits and physiology during the past 50 years. This drastic change in life-style is thought to be one of the main causes of modern diseases including obesity, type 2 diabetes, mental illness such as depression, sleep disorders, and certain types of cancer. These disorders have been associated to disruption of the circadian clock, an intrinsic time-keeper molecular system present in virtually all cells and tissues. The circadian clock is a key element in homeostatic regulation by controlling a large array of genes implicated in cellular metabolism. Importantly, intimate links between epigenetic regulation and the circadian clock exist and are likely to prominently contribute to the plasticity of the response to the environment. In this review, we summarize some experimental and epidemiological evidence showing how environmental factors such as stress, drugs of abuse and changes in circadian habits, interact through different brain areas to modulate the endogenous clock. Furthermore we point out the pivotal role of the deacetylase silent mating-type information regulation 2 homolog 1 (SIRT1) as a molecular effector of the environment in shaping the circadian epigenetic landscape.

Silent mating-type information regulation 2 homolog 1 overexpression is an important strategy for the survival of adapted suspension tumor cells.

Characterization of circulating tumor cells (CTC) is important to prevent death caused by the metastatic spread of cancer cells because CTC are associated with distal metastasis and poor prognosis of breast cancer. We have previously developed suspension cells (SC) using breast cancer cell lines and demonstrated their high metastatic potential. As survival of CTC is highly variable from a few hours to decades, herein we cultured SC for an extended time and named them adapted suspension cells (ASC). Silent mating‐type information regulation 2 homolog 1 (SIRT1) expression increased in ASC, which protected the cells from apoptosis. High SIRT1 expression was responsible for the suppression of nuclear factor kappa B (NF‐κB) activity and downregulation of reactive oxygen species (ROS) in ASC. As the inhibition of NF‐κB and ROS production in SIRT1‐depleted ASC contributed to the development of resistance to apoptotic cell death, maintenance of a low ROS level and NF‐κB activity in ASC is a crucial function of SIRT1. Thus, SIRT1 overexpression may play an important role in growth adaptation of SC because SIRT1 expression is increased in long‐term rather than in short‐term cultures.

SIRT 1 binding with PKM and NSE and modulate their acetylation and activities

SIRT1 (Silent mating type information regulation 2 homolog 1) play a neuroprotective effect through deacetylation target proteins in various neuronal diseases. However, the precise mechanisms remain elusive. In this study, we aim to identify those novel interacting partners of SIRT1 in rat brain tissue. By using a pre-clear GST-Pull down assay followed by the LC-MS/MS analysis, we've identified potential SIRT1's interacting partners, which function annotation by GO and KEGG analysis indicating some metabolic pathways are among the most enriched. Then we confirmed two candidates Enolase-1 (and NSE (Neuron-Specific Enolase) in brain) and PKM (Pyruvate Kinase Muscle) are associated with SIRT1 in brain tissue lysis by co-immunoprecipitation. Furthermore, increase or decrease the SIRT1 enzyme activity by its agonist SRT1720 or antagonist EX527 could significantly affect the acetylation level of endogenous NSE and PKM, SIRT1 overexpression or knock out expreiments also showed the same results as use SIRT1's agonist or antagonist. Moreover, the acetylation changes on NSE or PKM could finally lead to affection on their catalytic activity. Taken together, our findings suggest that the function of SIRT1 binding proteins is enriched in metabolic pathways. NSE and PKM are new SIRT1 binding molecules. SIRT1 may regulate acetylation level of NSE and PKM through deacetylation and further regulate their catalytic activity. Our study provides new evidence for the involvement of SIRT1 in the mechanisms of metabolic regulation in central nervous system.

Overexpression of SIRT1 in urothelial carcinoma of the urinary bladder is associated with local recurrence and poor survival

Objectives:To investigate the relationship of Silent mating type information regulation 2 homolog-1 (SIRT1) immunostaining to urothelial carcinoma of the urinary bladder (UCB) clinicopathological parameters.Methods:The study includes a total of 147 specimens composed of 122 urothelial carcinoma and 25 of non-neoplastic normal mucosae. The clinical information and the corresponding paraffin blocks of the cases were collected from the Pathology Department at King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia. Tissue microarrays were prepared and unstained slides were cut from the recipient blocks. Immunohistochemistry study was performed using anti-human SIRT1 antibody. The study was conducted from July 2016 until May 2018.Results:In UCB, high SIRT1 immunostaining (59.8%) was greater than low SIRT1 immunostaining (40.2%). High SIRT1 immunostaining was associated with local disease recurrence (p=0.017). However, there was no relation with other clinicopathological parameters. Regression analysis demonstrated that SIRT1 overexpression is an independent predictor of local disease recurrence (p=0.002). High SIRT1 immunostaining was associated with lower overall survival (log rank [Mantel-Cox]=6.478, and p=0.011) and disease-free survival (log rank [Mantel-Cox])=4.281, and p=0.039).Conclusion:The results revealed that SIRT1 is an important prognostic factor for UBC patients and is a potential target for therapeutic intervention. Further immunohistochemical and molecular evaluations are required to explore the mechanism of action of SIRT1 and to investigate molecular downstream of this potential biomarker in UCB.

D-Limonene protects PC12 cells against corticosterone-induced neurotoxicity by activating the AMPK pathway

The stress-induced hormone corticosterone initiates oxidative stress and inflammatory responses, culminating in cell apoptosis and neurological changes. We assessed the effects of d-Limonene on a PC12 cellular model of corticosterone-induced neurotoxicity, and whether these effects involved the AMP-activated protein kinase (AMPKα) pathway. PC12 cells were treated with corticosterone with or without d-limonene for 24 h. Western blots were performed to measure activation of AMPK pathway members [Silent mating type information regulation 2 homolog-1 (SIRT1), AMPKα, and nuclear factor (NFκB)], reactive oxygen species, inflammatory cytokines, and markers of apoptosis. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) was used to measure cell death after treatment. d-Limonene reversed the effects of corticosterone on PC12 cells: it decreased the levels of malondialdehyde (MDA) and nitric oxide (NO), activities of NADPH oxidase (p67-phox and p47-phox), expression of pro-inflammatory markers [inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin 6 (IL-6), interleukin 1β (IL-1β), and tumor necrosis factor α (TNF-α)], and expression of pro-apoptotic proteins [Bcl2 associated with X protein (Bax) and cleaved caspase-3)]. d-Limonene also increased levels of the antioxidant enzymes superoxide dismutase 1 (SOD1) and heme oxygenase 1 (HO-1) and the anti-apoptotic protein Bcl-2 while decreasing the number of TUNEL-positive cells. d-limonene significantly activated AMPKα and suppressed NF-κB nuclear translocation through up-regulation of SIRT1. Addition of compound C, an AMPK inhibitor, severely weakened these neuroprotective effects of d-limonene. d-Limonene has a neuroprotective effect on corticosterone-induced PC12 cell injury induced by activating the AMPKα signaling pathway, and thereby inhibiting reactive oxygen species and inflammatory factors. These data suggest that d-limonene might protect against neuronal death to improve depressive symptoms.

Retracted: Ras-PI3K-AKT signaling promotes the occurrence and development of uveal melanoma by downregulating H3K56ac expression.

Uveal melanoma (UM) is an intraocular malignant tumor characterized by rapid progression and recurrence. The current conventional treatments are unsatisfactory. Histone acetylation at H3 lysine 56 (H3K56ac) has been reported to be a tumor suppressor in breast cancer. However, whether H3K56ac prevents the occurrence and development of UM remains uninvestigated. The study aimed to explore the regulatory effect of H3K56ac on Ras-PI3K-AKT induced UM cells proliferation and migration. The vectors of pEGFP-RasWT , pEGFP-K-Ras G12V/Y40C , and pEGFP-N1 were transfected into MP46 cells, and protein levels of phosphorylated AKT Ser473 and H3K56ac were examined using western blot analysis. The effect of H3K56ac on cell proliferation and migration were studied using 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide, colony formation, and Transwell assays. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and chromatin immunoprecipitation assays were performed to determine the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) downstream genes. Further, the regulatory effects of silent mating type information regulation 2 homolog-1 (SIRT1), general control nonderepressible 5 (GCN5), and mouse double minute 2 homolog (MDM2) on Ras-PI3K-AKT affected H3K56ac expression were also investigated. H3K56ac expression was specifically downregulated by Ras-PI3K-AKT activation pathway. H3K56ac inhibited the tumorigenic effect of Ras-PI3K-AKT on MP46 cells viability, colony formation, and migration, as well as participated in regulating the transcription of PI3K/AKT downstream genes. SIRT1 silence recovered H3K56ac expression, and reversed the tumorigenic effect of Ras-PI3K-AKT activation on MP46 cells. Downregulation of H3K56ac induced by Ras-PI3K-AKT activation was found to be associated with MDM2-mediated the degradation of GCN5. The results demonstrated that Ras-PI3K-AKT signaling promoted UM cells proliferation and migration via downregulation of H3K56ac expression, which might be related to MDM2-mediated the degradation of GCN5.

Serum SIRT1 Is Associated with Frailty and Adipokines in Older Adults.

Because frailty is a major health concern among older patients, identifying frailty-related biomarkers will help in the early detection and prevention of frailty. Thus, we aimed to determine the association between circulating levels of silent mating-type information regulation 2 homolog 1 (SIRT1) and frailty. We assessed circulating SIRT1 levels in 16 robust, 74 prefrail, and 40 frail older adults. Frailty was diagnosed based on the Fried phenotype. Circulating cytokine and adipokine (e.g., vaspin, adiponectin, and leptin) levels were assessed. Differences in SIRT1 levels among the three subject groups were compared; correlations of SIRT1 levels with physical function and adipokine and cytokine levels were analyzed. Serum SIRT1 levels were significantly higher among frail older adults than among robust ones. Older adults with slowness or weight loss had high SIRT1 levels. Serum SIRT1 levels negatively correlated with gait speed, even after adjustment for age and sex; age; and insulin, vaspin, and leptin levels; they correlated negatively with phospholipase A2 levels. High SIRT1 levels were observed in frail elderly patients and were correlated with decreased physical function. Insulin and adipokine levels might be the link between SIRT1 and frailty, whereas inflammation may not be involved in this process.

The Role of SIRT1 in Autophagy in Lipopolysaccharide-Induced Mouse Type II Alveolar Epithelial Cells.

Silent mating type information regulation 2 homolog-1 (SIRT1) is involved in a wide range of cellular processes because of its role as a deacetylated histone and its association with a variety of transcription factors. SIRT1 has essential roles in autophagy, including in the formation of autophagic vacuoles and the assembly of autophagy-related gene (ATG) protein complexes. The present study focused on the role of SIRT1 in autophagy in lipopolysaccharide (LPS)-induced mouse type II alveolar epithelial cells (AECII). We designed experiments using SIRT1-overexpressing mice and wild-type mice, and AECII were isolated from these two types of mouse for in vitro LPS injury trials. Our results suggest that levels of the autophagy proteins, Beclin1 and LC3B, as well as those of the inflammatory factors, IL-6 and TNF-α, were increased in LPS-induced mouse AECII, and that SIRT1 protected against damage in mice with acute respiratory distress syndrome and in mouse AECII in vitro following LPS treatment. Subsequently, we screened multiple inflammatory, apoptotic, and unclassified genes (including Atg7), which interacted with SIRT1 in LPS-injured mouse AECII, as assessed by mRNA microarray analysis. These results demonstrate that LPS can reduce the levels of SIRT1 and ATG7 in vivo and in vitro and indicate that SIRT1 is involved in autophagy through regulation of ATG7 in AECII in response to LPS.

Clinicopathological and predictive significance of SIRT1 and peroxisome proliferator-activated receptor gamma in esophageal squamous cell carcinoma: The correlation with EGFR and Survivin

SIRT1 (silent mating type information regulation 2 homolog 1) is an enzyme that deacetylates proteins that contributes to cell survival and angiogenesis. Peroxisome proliferator-activated receptor Ƴ (PPAR Ƴ) is a member of the nuclear steroid hormone receptor superfamily and regulates cell apoptosis and proliferation. The functional roles of SIRT1 and PPAR Ƴ in tumor progression remain controversy. This study aims to investigate the roles of SIRT1 and PPAR Ƴ in esophageal squamous cell carcinoma (ESCC), as well as correlation with expression of EGFR and Survivin. Here, we analyzed the protein expression of SIRT1 and PPAR Ƴ in tumor microarray with ESCC and its associations with clinicopathological parameters and overall survival. Both SIRT1 and PPAR Ƴ were highly expressed in tumor tissues comparing with non-cancerous epithelium. High expression of SIRT1 was positively correlated with advanced TNM stage and poor outcome, while high expression of PPAR Ƴ was positively related with tumor grading, not with patients’ prognosis. In addition, the high expression of SIRT1 was positively correlated with overexpression of EGFR, not related with PPAR Ƴ or Survivin expression status. These data suggests SIRT1 may serve as a predictor of poor prognosis in ESCC, and its mediated tumor-promoting role might be associated with the overexpression of EGFR protein in ESCC.

The mechanistic target of rapamycin (mTOR) and the silent mating-type information regulation 2 homolog 1 (SIRT1): oversight for neurodegenerative disorders.

As a result of the advancing age of the global population and the progressive increase in lifespan, neurodegenerative disorders continue to increase in incidence throughout the world. New strategies for neurodegenerative disorders involve the novel pathways of the mechanistic target of rapamycin (mTOR) and the silent mating-type information regulation 2 homolog 1 (Saccharomyces cerevisiae) (SIRT1) that can modulate pathways of apoptosis and autophagy. The pathways of mTOR and SIRT1 are closely integrated. mTOR forms the complexes mTOR Complex 1 and mTOR Complex 2 and can impact multiple neurodegenerative disorders that include Alzheimer's disease, Huntington's disease, and Parkinson's disease. SIRT1 can control stem cell proliferation, block neuronal injury through limiting programmed cell death, drive vascular cell survival, and control clinical disorders that include dementia and retinopathy. It is important to recognize that oversight of programmed cell death by mTOR and SIRT1 requires a fine degree of precision to prevent the progression of neurodegenerative disorders. Additional investigations and insights into these pathways should offer effective and safe treatments for neurodegenerative disorders.

MiR-211 promotes lens epithelial cells apoptosis by targeting silent mating-type information regulation 2 homolog 1 in age-related cataracts

To detect the expression of miR-211 in age-related cataract tissue, explore the effects of miR-211 on lens epithelial cell proliferation and apoptosis, and identify its target gene. This study used real-time quantitative polymerase chain reaction (RT-qPCR) to measure the expression of miR-211 and its predicted target gene [silent mating-type information regulation 2 homolog 1 (SIRT1)] in 46 anterior lens capsules collected from age-related cataract patients. Human lens epithelial cell line (SRA01/04) cells were transfected with either miR-211 mimics, mimic controls, miR-211 inhibitors or inhibitor controls, 72h after transfection, miRNA and protein expression of SIRT1 were measured using RT-qPCR and Western blotting; then cells were exposed to 200 µmol/L H2O2 for 1h, whereupon cell viability was measured by MTS assay, caspase-3 assay was performed. Dual luciferase reporter assay was performed to verify the relationship between miR-211 of SIRT1. Compared to the control group, expression of miR-211 was significantly increased (P<0.001), the miRNA and protein expression of SIRT1 were significantly decreased (P<0.001) in the anterior lens capsules of patients with age-related cataracts. Relative to the control group, SIRT1 miRNA and protein levels in the miR-211 mimic group were significantly reduced, cell proliferation activity significantly decreased, and caspase-3 activity was significantly increased (P<0.001). In the miR-211 inhibitor group, SIRT1 miRNA and protein expression were significantly increased, cell proliferation activity significantly increased, and caspase-3 activity was significantly decreased (P<0.001). A dual luciferase reporter assay confirmed that SIRT1 is a direct target of miR-211. miR-211 is highly expressed in the anterior lens capsules of patients with age-related cataracts. By negatively regulating the expression of SIRT1, miR-211 promotes lens epithelial cell apoptosis and inhibits lens epithelial cell proliferation.

γ-Mangostin, a xanthone from mangosteen, attenuates oxidative injury in liver via NRF2 and SIRT1 induction

γ-Mangostin (γ-man), an active compound from Garcinia mangostana L., has been discovered as a hepatoprotective agent against oxidative injury. However, the underlying mechanisms remained unclear. The current study showed that γ-man stimulated the nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2) to enhance antioxidant capacity under oxidative stress, which was partially reversed by treatment of the NRF2 inhibitor, all-trans-retinoic acid. Moreover, γ-man increased the expression and activity of SIRT1 (silent mating type information regulation 2 homolog 1), which facilitated the deacetylation of peroxisome proliferator-activated receptor γ coactivator 1α to improve the mitochondrial function in L02 cells. The protective effect of γ-man was partially blocked by treatment of the SIRT1 inhibitor tenovin-1 or SIRT1 knockdown. In vivo studies showed γ-man protected mice from carbon tetrachloride-induced acute liver injury, through up-regulation of NRF2 and SIRT1. Thus, γ-man might be a candidate to protect liver from acute oxidative injury.

Resveratrol suppresses hyperoxia-induced nucleocytoplasmic shuttling of SIRT1 and ROS production in PBMC from preterm infants in vitro

Objective: By assessing silent mating-type information regulation 2 homolog 1 (SIRT1) nucleocytoplasmic shuttling and reactive oxygen species (ROS) levels in peripheral blood mononuclear cells (PBMCs), this study aimed to explore the role of SIRT1 in premature infants after exposure to hyperoxia and assess the protective effects of resveratrol (Res). Methods: Firstly, ROS levels as well as SIRT1 translocation and expression in PBMCs samples were evaluated from 40 premature infants with different oxygen amounts received at birth. Then, PBMCs, from additional 40 premature infants administered no oxygen at birth, were used to establish an in vitro model of hyperoxia. Results: In infants that received O2 at birth, ROS and MDA levels, and SIRT1 translocation rates gradually increased in a concentration-dependent manner, while SIRT1 gradually decreased. In agreement, PBMCs cultured in vitro showed increased ROS levels after exposed to hyperoxia, SIRT1 translocation increased as well. However, treatment with Res resulted in opposite effects. Conclusion: Res inhibits ROS release in PBMCs from preterm infants exposed to hyperoxia, likely by preventing SIRT1 nucleocytoplasmic shuttling and increasing SIRT1 expression.

Protective effect of total saponins of Panax notoginseng combined with total flavonoids of epimedium on D-galactose-incuced senescence of H9c2 cell

To investigate the protective effect of Panax notoginseng saponins combined with total flavonoids of epimedium on D-gal-induced senescence of H9c2 cells and explore its underlying mechanisms. The 50 mol•L⁻¹ D-gal was used to induce H9c2 cells senescence. Different concentrations of TPNS, TFE, and TPNS combined with TFE were used for 4 hours for pre-treatment. D-gal was used to stimulate H9c2 cardiac muscle cells for 24 h. Then in order to determine the best combined scheme, MTT was used to detect cell viability. Cell senescence was identified by β-galactosidase staining. Levels of reactive oxygen species(ROS) was observed by DCFH-DA detection. The changes of mitochondrial membrane potential were identified by JC-1 detection. Protein levels of silentmating type information regulation 2 Homolog-1(SIRT1), peroxisomal proliferator-activated receptor-coactivator 1α(PGC-1α) and silentmating type information regulation 2 Homolog-3(SIRT3) were detected by western blot analysis. The results showed that TPNS(5 mg•L⁻¹) combined with TFE(5 mg•L⁻¹) had significant synergistic effect on H9c2 myocardial cell proliferation(Q=1.154), so 5 mg•L-1TPNS combined with 5 mg•L⁻¹ TFE was determined as the best scheme. The quantity of β-galactosidase staining and the fluorescence intensity of ROS were apparently decreased in 5 mg•L⁻¹ TPNS combined with 5 mg•L⁻¹ TFE scheme. Meanwhile, it markedly increased the florescence intensity of mitochondrial membrane potential and enhanced the protein expression of SIRT1, PGC-1α and SIRT3. TPNS combined with TFE could protect H9c2 cells from D-gal-induced senescence. The mechanism might be related to adjusting the signal pathways of SIRT1/PGC-1α, SIRT3, adjusting the structure and function of mitochondria and reducing oxidative stress injury.

Anti-Fibrotic Effect of Losartan, an Angiotensin II Receptor Blocker, Is Mediated through Inhibition of ER Stress via Up-Regulation of SIRT1, Followed by Induction of HO-1 and Thioredoxin.

Endoplasmic reticulum (ER) stress is increasingly identified as modulator of fibrosis. Losartan, an angiotensin II receptor blocker, has been widely used as the first choice of treatment in chronic renal diseases. We postulated that anti-fibrotic effect of losartan is mediated through inhibition of ER stress via SIRT1 (silent mating type information regulation 2 homolog 1) hemeoxygenase-1 (HO-1)/thioredoxin pathway. Renal tubular cells, tunicamycin (TM)-induced ER stress, and unilateral ureteral obstruction (UUO) mouse model were used. Expression of ER stress was assessed by Western blot analysis and immunohistochemical stain. ER stress was induced by chemical ER stress inducer, tunicamycin, and non-chemical inducers such as TGF-β, angiotensin II, high glucose, and albumin. Losartan suppressed the TM-induced ER stress, as shown by inhibition of TM-induced expression of GRP78 (glucose related protein 78) and p-eIF2α (phosphospecific-eukaryotic translation initiation factor-2α), through up-regulation of SIRT1 via HO-1 and thioredoxin. Losartan also suppressed the ER stress by non-chemical inducers. In both animal models, losartan reduced the tubular expression of GRP78, which were abolished by pretreatment with sirtinol (SIRT1 inhibitor). Sirtinol also blocked the inhibitory effect of losartan on the UUO-induced renal fibrosis. These findings provide new insights into renoprotective effects of losartan and suggest that SIRT1, HO-1, and thioredoxin may be potential pharmacological targets in kidney diseases under excessive ER stress condition.

Methylene blue alleviates experimental autoimmune encephalomyelitis by modulating AMPK/SIRT1 signaling pathway and Th17/Treg immune response

Methylene blue (MB) is an effective neuroprotectant in many neurological disorders. AMP-activated protein kinase (AMPK)/silent mating-type information regulation 2 homolog 1 (SIRT1) plays a crucial role in maintaining inflammatory responses and shows a synergistic effect on cell homeostasis. We investigated the effect of MB on experimental autoimmune encephalomyelitis (EAE), a classical animal model of multiple sclerosis (MS). MB treatment reduced the clinical scores of EAE significantly and attenuated pathological injuries in spinal cords. Furthermore, the protective effects of MB were related to the activation of AMPK/SIRT1 signaling pathway. In addition, MB treatment alleviated T helper type17 (Th17) responses and increased regulatory T cell (Treg) responses. Our findings suggest that MB could be a promising reagent to treat autoimmune diseases and MS.

Treatment with NAD+ inhibited experimental autoimmune encephalomyelitis by activating AMPK/SIRT1 signaling pathway and modulating Th1/Th17 immune responses in mice

Nicotinamide adenine dinucleotide (NAD+) plays vital roles in mitochondrial functions, cellular energy metabolism and calcium homeostasis. In this study, we investigated the effect of NAD+ administration for the treatment of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice. EAE, a classical animal model of multiple sclerosis (MS), was induced by subcutaneous injection of myelin oligodendrocyteglycoprotein (MOG). The mice were treated with 250mg/kg (body weight) NAD+ in PBS administered intraperitoneally once daily. We observed that NAD+ treatment could lessen the severity of EAE. Additionally, NAD+ treatment attenuated pathological injuries of EAE mice. We also found that the AMP-activated protein kinase (AMPK)/silent mating-type information regulation 2 homolog 1(SIRT1) pathway was activated in the NAD+-treated mice and NAD+ treatment suppressed pro-inflammatory T cell responses. Our findings demonstrated that NAD+ could be an effective and promising agent to treat multiple sclerosis and its effects on other autoimmune diseases should be explored.

Mechanism of uncoupling protein2‑mediated myocardial injury in hypothermic preserved rat hearts.

In the present study, the alterations in uncoupling protein2 (UCP2) expression following hypothermic preservation in rat hearts were investigated. Isolated rat hearts were preserved in Celsior solution for 3‑12h followed by 60min of reperfusion. The cardiac function was evaluated using the Langendorff perfusion system. UCP2 and silent mating type information regulation2 homolog1 (SIRT1) proteins were detected by western blot analysis. The ATP production and mitochondrial reactive oxygen species (ROS) levels were assessed. Subsequent to preservation in ice‑cold Celsior solution for 3‑12h, the UCP2 protein expression in rat hearts was observed to increase in a time‑dependent manner. The UCP2 inhibitor genipin inhibited the hypothermic preservation‑induced cardiac dysfunction, prevented a decline in ATP production induced by 9h of preservation, however had no effect on the hypothermic preservation‑induced increase in mitochondrial ROS levels. Compared with the control group, the SIRT1 protein expression in rat hearts reduced following hypothermic preservation. Compared with the 9‑h preservation group, Celsior solution supplemented with the SIRT1 activator resveratrol (20 or 40µmol/l) inhibited UCP2 protein overexpression, prevented the decline in ATP production and resulted in an improvement cardiac function. The SIRT1 inhibitor EX‑527 abolished the resveratrol‑induced inhibition of UCP2 overexpression and cardiac protection in the hypothermic preserved rat heart. These observations suggest that downregulation of UCP2 expression in the hypothermic preserved rat heart in part initiated the protective mechanism via the SIRT1 pathway.

Angiotensin 1–7 Ameliorates Diabetic Cardiomyopathy and Diastolic Dysfunction in db/db Mice by Reducing Lipotoxicity and Inflammation

The angiotensin-converting enzyme 2 and angiotensin-(1-7) (Ang 1-7)/MasR (Mas receptor) axis are emerging as a key pathway that can modulate the development of diabetic cardiomyopathy. We studied the effects of Ang 1-7 on diabetic cardiomyopathy in db/db diabetic mice to elucidate the therapeutic effects and mechanism of action. Ang 1-7 was administered to 5-month-old male db/db mice for 28 days via implanted micro-osmotic pumps. Ang 1-7 treatment ameliorated myocardial hypertrophy and fibrosis with normalization of diastolic dysfunction assessed by pressure-volume loop analysis and echocardiography. The functional improvement by Ang 1-7 was accompanied by a reduction in myocardial lipid accumulation and systemic fat mass and inflammation and increased insulin-stimulated myocardial glucose oxidation. Increased myocardial protein kinase C levels and loss of phosphorylation of extracellular signal-regulated kinase 1/2 were prevented by Ang 1-7. Furthermore, Ang 1-7 treatment decreased cardiac triacylglycerol and ceramide levels in db/db mice, concomitantly with an increase in myocardial adipose triglyceride lipase expression. Changes in adipose triglyceride lipase expression correlated with increased SIRT1 (silent mating type information regulation 2 homolog 1) levels and deacetylation of FOXO1 (forkhead box O1). We identified a novel beneficial effect of Ang 1-7 on diabetic cardiomyopathy that involved a reduction in cardiac hypertrophy and lipotoxicity, adipose inflammation, and an upregulation of adipose triglyceride lipase. Ang 1-7 completely rescued the diastolic dysfunction in the db/db model. Ang 1-7 represents a promising therapy for diabetic cardiomyopathy associated with type 2 diabetes mellitus.