Silent information regulator 1 (SIRT1) is one of the seven mammalian proteins of the sirtuin family of NAD⁺-dependent deacetylases. SIRT1 plays a pivotal role in neuroprotection and ongoing research has uncovered a mechanism by which SIRT1 may exert a neuroprotective effect on Alzheimer's disease (AD). Growing evidence demonstrates that SIRT1 regulates many pathological processes including amyloid-β precursor protein (APP) processing, neuroinflammation, neurodegeneration, and mitochondrial dysfunction. SIRT1 has recently received enormous attention, and pharmacological or transgenic approaches to activate the sirtuin pathway have shown promising results in the experimental models of AD. In the present review, we delineate the role of SIRT1 in AD from a disease-centered perspective and provides an up-to-date overview of the SIRT1 modulators and their potential as effective therapeutics in AD.
Animals ; Alzheimer Disease ; Amyloid beta-Protein Precursor ; Animals, Genetically Modified ; Sirtuin 1 ; Sirtuins ; Humans

This study aims to explore the anti-depression mechanism of Zuojin Pills based on the plasma constituents, network pharmacology, and experimental verification. UHPLC-TOF-MS was used for qualitative analysis of Zuojin Pills-containing serum. Targets of the plasma constituents and the disease were retrieved from PharmMapper and GeneCards. Then the protein-protein interaction(PPI) network was constructed and core targets were screened for GO term enrichment and KEGG pathway enrichment. Cytoscape 3.7.2 was employed construct the "compound-target-pathway" network and the targets and signaling pathways of Zuojin Pills against depression were predicted. CUMS-induced depression mouse model was established to verify the key targets. The results showed that a total of 21 constituents migrating to blood of Zuojin Pills were identified, which were mainly alkaloids. A total of 155 common targets of the constituents and the disease and 67 core targets were screened out. KEGG enrichment and PPI network analysis showed that Zuojin Pills may play a role in the treatment of depression through AMPK/SIRT1, NLRP3, insulin and other targets and pathways. Furthermore, the results of animal experiments showed that Zuojin Pills could significantly improve the depression behaviors of depression, reduce the levels of IL-1β, IL-6 and TNF-α in hippocampus and serum, activate AMPK/SIRT1 signaling, and reduce the protein expression of NLRP3. In conclusion, Zuojin Pills may play a role in the treatment of depression by activating AMPK/SIRT1 signaling pathway, and inhibiting NLRP3 activation and neuroinflammation in the hippocampus of mice.
Animals ; Mice ; Network Pharmacology ; AMP-Activated Protein Kinases ; Chromatography, High Pressure Liquid ; NLR Family, Pyrin Domain-Containing 3 Protein ; Sirtuin 1 ; Drugs, Chinese Herbal/pharmacology* ; Molecular Docking Simulation

Resveratrol (RES), a natural polyphenolic phytochemical, has been suggested as a putative anti-aging molecule for the prevention and treatment of Alzheimer's disease (AD) by the activation of sirtuin 1 (Sirt1/Sir2). In this study, we tested the effects of RES and Sirt1/Sir2 on sleep and courtship memory in a Drosophila model by overexpression of amyloid precursor protein (APP), whose duplications and mutations cause familial AD. We found a mild but significant transcriptional increase of Drosophila Sir2 (dSir2) by RES supplementation for up to 17 days in APP flies, but not for 7 days. RES and dSir2 almost completely reversed the sleep and memory deficits in APP flies. We further demonstrated that dSir2 acts as a sleep promotor in Drosophila neurons. Interestingly, RES increased sleep in the absence of dSir2 in dSir2-null mutants, and RES further enhanced sleep when dSir2 was either overexpressed or knocked down in APP flies. Finally, we showed that Aβ aggregates in APP flies were reduced by RES and dSir2, probably via inhibiting Drosophila β-secretase (dBACE). Our data suggest that RES rescues the APP-induced behavioral deficits and Aβ burden largely, but not exclusively, via dSir2.
Animals ; Alzheimer Disease/metabolism* ; Amyloid beta-Peptides ; Amyloid beta-Protein Precursor/metabolism* ; Drosophila/physiology* ; Drosophila Proteins/metabolism* ; Resveratrol/pharmacology* ; Sirtuin 1 ; Sleep

Sirtuin 1

OBJECTIVE: To investigate the role and mechanism of silent information regulator 1 (SIRT1) in regulating nuclear factor E2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway in oxidative stress and inflammatory response to sepsis-induced liver injury. METHODS: A total of 24 male Sprague-Dawley (SD) rats were randomly divided into sham operation (Sham) group, cecal ligation and puncture (CLP) group, SIRT1 agonist SRT1720 pretreatment (CLP+SRT1720) group and SIRT1 inhibitor EX527 pretreatment (CLP+EX527) group, with 6 rats in each group. Two hours before operation, SRT1720 (10 mg/kg) or EX527 (10 mg/kg) were intraperitoneally injected into the CLP+SRT1720 group and CLP+EX527 group, respectively. Blood was collected from the abdominal aorta at 24 hours after modeling and the rats were sacrificed for liver tissue. The serum levels of interleukins (IL-6, IL-1β) and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immunosorbent assay (ELISA). The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected by microplate method. Hematoxylin-eosin (HE) staining was used to observe the pathological injury of rats in each group. The levels of malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), glutathione (GSH) and superoxide dismutase (SOD) in liver tissue were detected by corresponding kits. The mRNA and protein expressions of SIRT1, Nrf2 and HO-1 in liver tissues were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting. RESULTS: Compared with the Sham group, the serum levels of IL-6, IL-1β, TNF-α, ALT and AST in the CLP group were significantly increased; histopathological results showed that liver cords were disordered, hepatocytes were swollen and necrotic, and a large number of inflammatory cells infiltrated; the contents of MDA and 8-OHdG in liver tissue increased, while the contents of GSH and SOD decreased; and the mRNA and protein expressions of SIRT1, Nrf2 and HO-1 in liver tissues were significantly decreased. These results suggest that sepsis rats have liver dysfunction, and the levels of SIRT1, Nrf2, HO-1 and antioxidant protein in liver tissues were decreased, while the levels of oxidative stress and inflammation were increased. Compared with the CLP group, the levels of inflammatory factors and oxidative stress were significantly decreased in the CLP+SRT1720 group, the mRNA and protein expressions of SIRT1, Nrf2 and HO-1 were significantly increased [IL-6 (ng/L): 34.59±4.21 vs. 61.84±3.78, IL-1β (ng/L): 41.37±2.70 vs. 72.06±3.14, TNF-α (ng/L): 76.43±5.23 vs. 130.85±5.30, ALT (U/L): 30.71±3.63 vs. 64.23±4.59, AST (U/L): 94.57±6.08 vs. 145.15±6.86, MDA (μmol/g): 6.11±0.28 vs. 9.23±0.29, 8-OHdG (ng/L): 117.43±10.38 vs. 242.37±11.71, GSH (μmol/g): 11.93±0.88 vs. 7.66±0.47, SOD (kU/g): 121.58±5.05 vs. 83.57±4.84, SIRT1 mRNA (2^-ΔΔCt): 1.20±0.13 vs. 0.46±0.02, Nrf2 mRNA (2^-ΔΔCt): 1.21±0.12 vs. 0.58±0.03, HO-1 mRNA (2^-ΔΔCt): 1.71±0.06 vs. 0.48±0.07, SIRT1 protein (SIRT1/β-actin): 0.89±0.04 vs. 0.58±0.03, Nrf2 protein (Nrf2/β-actin): 0.87±0.08 vs. 0.51±0.09, HO-1 protein (HO-1/β-actin): 0.93±0.14 vs. 0.54±0.12, all P < 0.05], these results indicated that SIRT1 agonist SRT1720 pretreatment could improve liver injury in sepsis rats. However, pretreatment with SIRT1 inhibitor EX527 showed the opposite effect [IL-6 (ng/L): 81.05±6.47 vs. 61.84±3.78, IL-1β (ng/L): 93.89±5.83 vs. 72.06±3.14, TNF-α (ng/L): 177.67±5.12 vs. 130.85±5.30, ALT (U/L): 89.33±9.52 vs. 64.23±4.59, AST (U/L): 179.59±6.44 vs. 145.15±6.86, MDA (μmol/g): 11.39±0.51 vs. 9.23±0.29, 8-OHdG (ng/L): 328.83±11.26 vs. 242.37±11.71, GSH (μmol/g): 5.07±0.34 vs. 7.66±0.47, SOD (kU/g): 59.37±4.28 vs. 83.57±4.84, SIRT1 mRNA (2^-ΔΔCt): 0.34±0.03 vs. 0.46±0.02, Nrf2 mRNA (2^-ΔΔCt): 0.46±0.04 vs. 0.58±0.03, HO-1 mRNA (2^-ΔΔCt): 0.21±0.03 vs. 0.48±0.07, SIRT1 protein (SIRT1/β-actin): 0.47±0.04 vs. 0.58±0.03, Nrf2 protein (Nrf2/β-actin): 0.32±0.07 vs. 0.51±0.09, HO-1 protein (HO-1/β-actin): 0.19±0.09 vs. 0.54±0.12, all P < 0.05]. CONCLUSIONS SIRT1 can inhibit the release of proinflammatory factors and alleviate the oxidative damage of hepatocytes by activating Nrf2/HO-1 signaling pathway, thus playing a protective role against CLP-induced liver injury.
Animals ; Male ; Rats ; Actins/metabolism* ; Chemical and Drug Induced Liver Injury, Chronic ; Heme Oxygenase-1/metabolism* ; Interleukin-6 ; NF-E2-Related Factor 2/metabolism* ; Rats, Sprague-Dawley ; RNA, Messenger ; Sepsis/metabolism* ; Signal Transduction ; Sirtuin 1/metabolism* ; Superoxide Dismutase/metabolism* ; Tumor Necrosis Factor-alpha/metabolism*

OBJECTIVE: To investigate the role of the SIRT1/NF-κB pathway in mediating the effect of puerarin against lipopolysaccharide (LPS)-induced acute kidney injury (AKI). METHODS: Fifteen BALB/C mice were randomized into control group, LPS group and puerarin treatment group, and in the latter two groups, the mice were given an intraperitoneal injection of LPS (5 mg/kg), followed by daily injection of normal saline for 3 days or injection of puerarin (25 mg/kg) given 1 h later and then on a daily basis for 3 days. On day 5 after modeling, the kidney tissues were taken for histological observation and detection of cell apoptosis. The renal function indexes including urea nitrogen (BUN), serum creatinine (Scr) and kidney injury molecule 1 (KIM-1) and the levels of tumor necrosis factor (TNF-α) and interleukin 1β (IL-1β) were measured, and the expressions of SIRT1 and NF-κB-p65(acetyl K310) in the renal tissues were detected. RESULTS: Intraperitoneal injection of LPS caused obvious glomerular capillary dilatation, hyperemia, renal interstitial edema, and renal tubular epithelial cell swelling and deformation in the mice. The mouse models of LPS-induced AKI also showed significantly increased renal tubular injury score and renal cell apoptosis (P < 0.01) with increased serum levels of BUN, Scr, KIM-1, TNF-α and IL-1β (P < 0.01), enhanced renal expressions of TNF-α, IL-1β and NF-κB p65(acetyl K310) (P < 0.01) and lowered renal expression of SIRT1 (P < 0.05). Treatment with puerarin effectively alleviated LPS-induced renal interstitial edema and renal tubular epithelial cell shedding, lowered renal tubular injury score (P < 0.01) and renal cell apoptosis rate (P < 0.01), and decreased serum levels of BUN, Scr, KIM, TNF-α and IL-1β (P < 0.01). Puerarin treatment significantly reduced TNF-α, IL-1β and NF-κB p65 (acetyl K310) expression in the renal tissue (P < 0.05) and increased SIRT1 expression by 17% (P < 0.05) in the mouse models. CONCLUSION Puerarin can effectively alleviate LPS-induced AKI in mice possibly by modulating the SIRT1/NF-κB signaling pathway.
Animals ; Mice ; Mice, Inbred BALB C ; NF-kappa B ; Lipopolysaccharides ; Sirtuin 1 ; Tumor Necrosis Factor-alpha ; Acute Kidney Injury ; Disease Models, Animal ; Edema

OBJECTIVE: To analyze the correlation between the expression of silencing information regulator 2 related enzyme 1 (SIRT1), tumor necrosis factor like weak inducer of apoptosis (TWEAK) and knee osteoarthritis. METHODS: Total of 103 patients with knee joint (knee osteoarthritis group) from February 2019 to August 2021 were selected including 40 males and 63 females with an average age of (62.02±6.09) years;according to the modified Mankin score, 103 patients were divided into mild group (Mankin score 1-4 points, 31 cases) and moderate group (Mankin score 5-8 points, 40 cases) and severe group (Mankin score ≥9, 32 cases). Another 105 physical examination volunteers were selected as the control group including 46 males and 59 females with an average age of (62.11±6.34) years old. The levels of SIRT1 and TWEAK in articular effusion and serum were detected in the knee osteoarthritis group, while serum SIRT1 and TWEAK were detected in the control group only. The relationship between SIRT1, TWEAK and the occurrence and disease of knee osteoarthritis were analyzed. RESULTS: Articular cavity fluid TWEAK, serum TWEAK, CRP, IL-6, IL-1β, white blood cell count and ESR were higher than those in the control group(P<0.05), articular cavity fluid SIRT1 and serum SIRT1 were lower than those in the control group(P<0.05). TWEAK level in the severe group was higher than that in the moderate and mild groups(P<0.05), SIRT1 was lower than that in the moderate and mild groups (P<0.05). The level of SIRT1 in articular cavity effusion was positively correlated with the serum level of SIRT1 (P<0.05), and negatively correlated with CRP, IL-6, IL-1β, white blood cell count, modified Mankin score and ESR (P<0.05). TWEAK level in articular cavity fluid was positively correlated with serum TWEAK level (P<0.05), C-reactive protein(CRP), interleukin(IL)-6, IL-1β, white blood cell count, modified Mankin score and erythrocyte sedimentation rate(ESR) (P<0.05). Body mass index, undertaking heavy physical work, and articular cavity fluid TWEAK were risk factors for the occurrence of knee osteoarthritis(P<0.05), and articular cavity fluid SIRT1 was a protective factor for the occurrence of knee arthritis (P<0.05). The area under curve(AUC) of SIRT1 and TWEAK for knee osteoarthritis was 0.641 and 0.653, and the AUC of SIRT1 and TWEAK for knee osteoarthritis was 0.879, which was higher than SIRT1 and TWEAK alone (z=6.105 and 6.225, P<0.05). CONCLUSION The level of SIRT1 in articular fluid in patients with knee arthritis is decreased and the level of TWEAK is increased. Low SIRT1 and high TWEAK are associated with the onset and exacerbation of knee osteoarthritis.
Aged ; Female ; Humans ; Male ; Middle Aged ; Apoptosis ; Interleukin-6 ; Osteoarthritis, Knee/pathology* ; Sirtuin 1/blood* ; Cytokine TWEAK/blood*

Objective To investigate the role of proanthocyanidins (PC) in lipopolysaccharide (LPS)-induced inflammatory response and its possible mechanism in RAW264.7 macrophages. Methods RAW264.7 macrophages were cultured and treated with PBS and different concentrations of PC for 24 hours, followed by 1 μg/mL LPS for 6 hours. Real-time PCR was used to detect the mRNA expression of interleukin1β (IL-1β), IL-6, monocyte chemoattractant protein 1 (MCP-1), tumor necrotic factor α (TNF-α), IL-4 and arginase 1 (Arg1) in RAW264.7 macrophages. Flow cytometry was used to detect the effects of PBS group, LPS group and PC combined with LPS group on M1 and M2 polarization of macrophages. The protein expressions of silenced information regulator 1 (SIRT1), nuclear factor kappa B p65(NF-κB p65) and acetylated NF-κB p65 (Ace-p65) were detected by Western blot analysis after different concentrations of PC treatment. Co-immunoprecipitation assay was used to detect the binding effect of SIRT1 to NF-κB p65 in macrophages treated with PC. Results Compared with PBS group, the mRNA expression of macrophage pro-inflammatory cytokines IL-1β, IL-6, MCP-1 and TNF-α decreased and the mRNA expression of anti-inflammatory factors IL-4 and Arg1 increased in PC group. Compared with LPS group, PC combined with LPS group could significantly inhibit M1 polarization and promote M2 polarization of macrophages. With the increase of PC concentration, the expression of SIRT1 was up-regulated, and NF-κB p65 protein did not change significantly. The expression of Ace-p65 protein decreased significantly when treated with high concentration of PC. Conclusion PC can significantly alleviate the LPS-induced inflammatory response by up-regulating the expression of SIRT1 and inhibiting NF-κB pathway in RAW264.7 macrophages.
Animals ; Mice ; Interleukin-4 ; Interleukin-6 ; Lipopolysaccharides ; Macrophages ; NF-kappa B ; Proanthocyanidins ; RNA, Messenger ; Sirtuin 1/genetics* ; Tumor Necrosis Factor-alpha ; RAW 264.7 Cells

OBJECTIVE: To explore the possible effects and mechanism of Zhizhu Decoction (ZZD) on the pathophysiology of slow transit constipation (STC). METHODS: A total of 54 C57BL/6 mice was randomly divided into the following 6 groups by a random number table, including control, STC model (model), positive control, and low-, medium- and high-doses ZZD treatment groups (5, 10, 20 g/kg, namely L, M-, and H-ZZD, respectively), 9 mice in each group. Following 2-week treatment, intestinal transport rate (ITR) and fecal water content were determined, and blood and colon tissue samples were collected. Hematoxylin-eosin and periodic acid-Schiff staining were performed to evaluate the morphology of colon tissues and calculate the number of goblet cells. To determine intestinal permeability, serum levels of lipopolysaccharide (LPS), low-density lipoprotein (LDL) and mannose were measured using enzyme-linked immunosorbent assay (ELISA). Western blot analysis was carried out to detect the expression levels of intestinal tight junction proteins zona-occludens-1 (ZO-1), claudin-1, occludin and recombinant mucin 2 (MUC2). The mRNA expression levels of inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-4, IL-10 and IL-22 were determined using reverse transcription-quantitative reverse transcription reaction. Colon indexes of oxidative stress were measured by ELISA, and protein expression levels of colon silent information regulator 1/forkhead box O transcription factor 1 (SIRT1/FoxO1) antioxidant signaling pathway were detected by Western blot. RESULTS: Compared with the model group, ITR and fecal moisture were significantly enhanced in STC mice in the M-ZZD and H-ZZD groups (P<0.01). Additionally, ZZD treatment notably increased the thickness of mucosal and muscular tissue, elevated the number of goblet cells in the colon of STC mice, reduced the secretion levels of LPS, LDL and mannose, and upregulated ZO-1, claudin-1, occludin and MUC2 expressions in the colon in a dose-dependent manner, compared with the model group (P<0.05 or P<0.01). In addition, ZZD significantly attenuated intestinal inflammation and oxidative stress and activated the SIRT1/FoxO1 signaling pathway (P<0.05 or P<0.01). CONCLUSION ZZD exhibited beneficial effects on the intestinal system of STC mice and alleviated intestinal inflammation and oxidative stress via activating SIRT1/FoxO1 antioxidant signaling pathway in the colon.
Mice ; Animals ; Sirtuin 1/genetics* ; Antioxidants ; Occludin ; Lipopolysaccharides ; Claudin-1 ; Mannose ; Mice, Inbred C57BL ; Constipation/drug therapy* ; Inflammation ; Signal Transduction

OBJECTIVE: To interpret the pharmacology of quercetin in treatment of atherosclerosis (AS). METHODS: Fourteen apolipoprotein E-deficient (ApoE^-/-) mice were divided into 2 groups by a random number table: an AS model (ApoE^-/-) group and a quercetin treatment group (7 in each). Seven age-matched C57 mice were used as controls (n=7). Quercetin [20 mg/(kg·d)] was administered to the quercetin group intragastrically for 8 weeks for pharmacodynamic evaluation. Besides morphological observation, the distribution of CD11b, F4/80, sirtuin 1 (Sirt1) and P21 was assayed by immunohistochemistry and immunofluorescence to evaluate macrophage infiltration and tissue senescence. Ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MSC/MS) was performed to study the pharmacology of quercetin against AS. Then, simultaneous administration of an apelin receptor antagonist (ML221) with quercetin was conducted to verify the possible targets of quercetin. Key proteins in apelin signaling pathway, such as angiotensin domain type 1 receptor-associated proteins (APJ), AMP-activated protein kinase (AMPK), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), tissue plasminogen activator (TPA), uncoupling protein 1 (UCP1) and angiotensin II receptor 1 (AT1R), were assayed by Western blot. RESULTS: Quercetin administration decreased lipid deposition in arterial lumen and improved the morphology of ApoE^-/- aortas in vivo. Quercetin decreased the densities of CD11b, F4/80 and P21 in the aorta and increased the level of serum apelin and the densities of APJ and Sirt1 in the aorta in ApoE^-/- mice (all P<0.05). Plasma metabolite profiling identified 118 differential metabolites and showed that quercetin affected mainly glycerophospholipids and fatty acyls. Bioinformatics analysis suggested that the apelin signaling pathway was one of the main pathways. Quercetin treatment increased the protein expressions of APJ, AMPK, PGC-1α, TPA and UCP1, while decreased the AT1R level (all P<0.05). After the apelin pathway was blocked by ML221, the effect of quercetin was abated significantly, confirming that quercetin attenuated AS by modulating the apelin signaling pathway (all P<0.05). CONCLUSION Quercetin alleviated AS lesions by up-regulation the apelin signaling pathway.
Mice ; Animals ; Apelin ; Tissue Plasminogen Activator/metabolism* ; Quercetin/therapeutic use* ; AMP-Activated Protein Kinases/metabolism* ; Sirtuin 1/metabolism* ; Signal Transduction/physiology* ; Atherosclerosis/metabolism* ; Apolipoproteins E