RESUMO
Myocardial ischemia-reperfusion (I/R) injury exacerbates cellular damage upon restoring blood flow to ischemic cardiac tissue, causing oxidative stress, inflammation, and apoptosis. This study investigates Nicotinamide Riboside (NR), a precursor of nicotinamide adenine dinucleotide (NAD+), for its cardioprotective effects. Administering NR to mice before I/R injury and evaluating heart function via echocardiography showed that NR significantly improved heart function, increased left ventricular ejection fraction (LVEF) and fractional shortening (FS), and reduced left ventricular end-diastolic (LVDd) and end-systolic diameters (LVSd). NR also restored E/A and E/e' ratios. It reduced cardiomyocyte apoptosis both in vivo and in vitro, inhibiting elevated caspase-3 activity and returning Bax protein levels to normal. In vitro, NR reduced the apoptotic rate in hydrogen peroxide (H2O2)-treated HL-1 cells from 30% to 10%. Mechanistically, NR modulated the SIRT3/mtROS/JNK pathway, reversing H2O2-induced SIRT3 downregulation, reducing mitochondrial reactive oxygen species (mtROS), and inhibiting JNK activation. Using SIRT3-knockout (SIRT3-KO) mice, we confirmed that NR's cardioprotective effects depend on SIRT3. Echocardiography showed that NR's benefits were abrogated in SIRT3-KO mice. In conclusion, NR provides significant cardioprotection against myocardial I/R injury by enhancing NAD+ levels and modulating the SIRT3/mtROS/JNK pathway, suggesting its potential as a novel therapeutic agent for ischemic heart diseases, meriting further clinical research.
Assuntos
Apoptose , Camundongos Knockout , Traumatismo por Reperfusão Miocárdica , Niacinamida , Compostos de Piridínio , Espécies Reativas de Oxigênio , Sirtuína 3 , Animais , Sirtuína 3/metabolismo , Sirtuína 3/genética , Traumatismo por Reperfusão Miocárdica/tratamento farmacológico , Traumatismo por Reperfusão Miocárdica/metabolismo , Traumatismo por Reperfusão Miocárdica/patologia , Niacinamida/análogos & derivados , Niacinamida/farmacologia , Niacinamida/uso terapêutico , Camundongos , Compostos de Piridínio/farmacologia , Compostos de Piridínio/administração & dosagem , Espécies Reativas de Oxigênio/metabolismo , Apoptose/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Estresse Oxidativo/efeitos dos fármacos , Humanos , Cardiotônicos/farmacologia , Cardiotônicos/uso terapêutico , Modelos Animais de Doenças , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Camundongos Endogâmicos C57BL , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: Ventilator-induced lung injury (VILI) is one of the severe complications in the clinic concerning mechanical ventilation (MV). Capsaicin (CAP) has anti-inflammatory and inhibitory effects on oxidative stress, which is a significant element causing cellular ferroptosis. Nevertheless, the specific role and potential mechanistic pathways through which CAP modulates ferroptosis in VILI remain elusive. METHODS: VILI was established in vivo, and the pulmonary epithelial cell injury model induced by circulation stretching (CS) was established in vitro. Both mice and cells were pretreated with CAP. Transmission electron microscopy, ELISA, Western blot, immunofluorescence, RT-PCR, fluorescent probes, and other experimental methods were used to clarify the relationship between iron death and VILI in alveolar epithelial cells, and whether capsaicin alleviates VILI by inhibiting iron death and its specific mechanism. RESULTS: Ferroptosis was involved in VILI by utilizing in vivo models. CAP inhibited ferroptosis and alleviated VILI's lung damage and inflammation, and this protective effect of CAP was dependent on maintaining mitochondrial redox system through SITR3 signaling. In the CS-caused lung epithelial cell injury models, CAP reduced pathological CS-caused ferroptosis and cell injury. Knockdown SIRT3 reversed the role of CAP on the maintaining mitochondria dysfunction under pathological CS and eliminated its subsequent advantageous impacts for ferroptosis against overstretching cells. CONCLUSION: The outcomes showed that CAP alleviated ferroptosis in VILI via improving the activity of SITR3 to suppressing mitochondrial oxidative damage and maintaining mitochondrial redox homeostasis, illustrating its possibility as a novel therapeutic goal for VILI.
Assuntos
Capsaicina , Ferroptose , Homeostase , Mitocôndrias , Oxirredução , Sirtuína 3 , Lesão Pulmonar Induzida por Ventilação Mecânica , Ferroptose/efeitos dos fármacos , Animais , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Camundongos , Sirtuína 3/metabolismo , Sirtuína 3/genética , Lesão Pulmonar Induzida por Ventilação Mecânica/metabolismo , Lesão Pulmonar Induzida por Ventilação Mecânica/tratamento farmacológico , Oxirredução/efeitos dos fármacos , Capsaicina/farmacologia , Masculino , Modelos Animais de Doenças , Humanos , Camundongos Endogâmicos C57BL , Estresse Oxidativo/efeitos dos fármacos , Células Epiteliais Alveolares/metabolismo , Células Epiteliais Alveolares/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacosRESUMO
BACKGROUND: The established association between Alzheimer's disease (AD) and compromised neural regeneration is well-documented. In addition to the mitigation of apoptosis in neural stem cells (NSCs), the induction of neurogenesis has been proposed as a promising therapeutic strategy for AD. Our previous research has demonstrated the effective inhibition of NSC injury induced by microglial activation through the repression of oxidative stress and mitochondrial dysfunction by Sirtuin 3 (SIRT3). Nonetheless, the precise role of SIRT3 in neurogenesis remains incompletely understood. METHODS: In vivo, SIRT3 overexpression adenovirus was firstly injected by brain stereotaxic localization to affect the hippocampal SIRT3 expression in APP/PS1 mice, and then behavioral experiments were performed to investigate the cognitive improvement of SIRT3 in APP/PS1 mice, as well as neurogenic changes in hippocampal region by immunohistochemistry and immunofluorescence. In vitro, under the transwell co-culture condition of microglia and neural stem cells, the mechanism of SIRT3 improving neurogenesis of neural stem cells through DVL/GSK3/ISL1 axis was investigated by immunoblotting, immunofluorescence and other experimental methods. RESULTS: Our findings indicate that the overexpression of SIRT3 in APP/PS1 mice led to enhanced cognitive function and increased neurogenesis. Additionally, SIRT3 was observed to promote the differentiation of NSCs into neurons during retinoic acid (RA)-induced NSC differentiation in vitro, suggesting a potential role in neurogenesis. Furthermore, we observed the activation of the Wnt/ß-catenin signaling pathway during this process, with Glycogen Synthase Kinase-3a (GSK3a) primarily governing NSC proliferation and GSK3ß predominantly regulating NSC differentiation. Moreover, the outcomes of our study demonstrate that SIRT3 exerts a protective effect against microglia-induced apoptosis in neural stem cells through its interaction with DVLs. CONCLUSIONS: Our results show that SIRT3 overexpressing APP/PS1 mice have improved cognition and neurogenesis, as well as improved neurogenesis of NSC in microglia and NSC transwell co-culture conditions through the DVL/GSK3/ISL1 axis.
Assuntos
Doença de Alzheimer , Células-Tronco Neurais , Neurogênese , Transdução de Sinais , Sirtuína 3 , Animais , Sirtuína 3/metabolismo , Sirtuína 3/genética , Camundongos , Doença de Alzheimer/metabolismo , Doença de Alzheimer/terapia , Doença de Alzheimer/genética , Células-Tronco Neurais/metabolismo , Células-Tronco Neurais/citologia , Quinase 3 da Glicogênio Sintase/metabolismo , Proteínas Desgrenhadas/metabolismo , Proteínas Desgrenhadas/genética , Camundongos Transgênicos , Microglia/metabolismo , Diferenciação Celular , Hipocampo/metabolismoRESUMO
BACKGROUND: Thoracic aortic dissection (TAD) is an irreversible cardiovascular disorder with high mortality and morbidity. However, the molecular mechanisms remain elusive. Thus, identifying an effective therapeutic target to prevent TAD is especially critical. The purpose of this study is to elucidate the potential mechanism of inflammation and vascular smooth muscle cell (VSMCs) phenotypic switch in ß-aminopropionitrile fumarate (BAPN)-induced TAD. METHODS: A mouse model of TAD induced by BAPN and IL-1ß -stimulated HVSMCs in vivo and in vitro models, respectively. ACE2 Knockdown mice treated with BAPN or without, and the TAD mouse model was treated with or without AAV-ACE2. Transthoracic ultrasound was conducted for assessment the maximum internal diameter of the thoracic aorta arch. RNA sequencing analysis was performed to recapitulate transcriptome profile changes. Western blot were used to detect the expression of MMP2, MMP9, ACE2, SIRT3, OPN, SM22α and other inflammatory markers. The circulating levels of ACE2 was measured by ELISA assay. Histological changes of thoracic aorta tissues were assessed by H&E, EVG and IHC analysis. RESULTS: We found that circulating levels of and the protein levels of ACE2 were increased in the TAD mouse model and in patients with TAD. For further evidence, ACE2 deficiency decelerated the formation of TAD. However, overexpression of ACE2 aggravated BAPN-induced aortic injury and VSMCs phenotypic switch via lowered SIRT3 expression and elevated inflammatory cytokine expression. CONCLUSION: ACE2 deficiency prevented the development of TAD by inhibiting inflammation and VSMCs phenotypic switch in a SIRT3-dependent manner, suggesting that the ACE2/SIRT3 signaling pathway played a pivotal role in the pathological process of TAD and might be a potential therapeutical target.
Assuntos
Enzima de Conversão de Angiotensina 2 , Aneurisma da Aorta Torácica , Dissecção Aórtica , Modelos Animais de Doenças , Inflamação , Músculo Liso Vascular , Miócitos de Músculo Liso , Sirtuína 3 , Animais , Enzima de Conversão de Angiotensina 2/metabolismo , Enzima de Conversão de Angiotensina 2/genética , Camundongos , Dissecção Aórtica/metabolismo , Dissecção Aórtica/etiologia , Dissecção Aórtica/genética , Dissecção Aórtica/patologia , Miócitos de Músculo Liso/metabolismo , Sirtuína 3/metabolismo , Sirtuína 3/genética , Sirtuína 3/deficiência , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patologia , Inflamação/metabolismo , Aneurisma da Aorta Torácica/metabolismo , Aneurisma da Aorta Torácica/etiologia , Aneurisma da Aorta Torácica/genética , Masculino , Fenótipo , Humanos , Camundongos Knockout , Aorta Torácica/metabolismo , Aorta Torácica/patologia , Aorta Torácica/efeitos dos fármacos , Aminopropionitrilo/farmacologia , Camundongos Endogâmicos C57BL , Dissecção da Aorta TorácicaRESUMO
The field of reproductive biology has made significant progress in recent years, identifying specific molecular players that influence oocyte development and function. Among them, sirtuin 3 (SIRT3) has attracted particular attention for its central role in mediating mitochondrial function and cellular stress responses in oocytes. So far, studies have demonstrated that the knockdown of SIRT3 leads to a decrease in blastocyst formation and an increase in oxidative stress within an embryo, underscoring the importance of SIRT3 in maintaining the cellular redox balance critical for embryonic survival and growth. Furthermore, the literature reveals specific signaling pathways, such as the SIRT3- Glycogen synthase kinase-3 beta (GSK3ß) deacetylation pathway, crucial for mitigating oxidative stress-related anomalies in oocyte meiosis, particularly under conditions like maternal diabetes. Overall, the emerging role of SIRT3 in regulating oocyte mitochondrial function and development highlights the critical importance of understanding the intricate connections between cellular metabolism, stress response pathways, and overall reproductive health and function. This knowledge could lead to the development of novel strategies to support oocyte quality and fertility, with far-reaching implications for assisted reproductive technologies and women's healthcare. This commentary aims to provide an overview of the importance of SIRT3 in oocytes by synthesizing results from a multitude of studies. The aim is to elucidate the role of SIRT3 in oocyte development, maturation, and aging and to identify areas where further research is needed.
Assuntos
Oócitos , Sirtuína 3 , Oócitos/metabolismo , Sirtuína 3/metabolismo , Sirtuína 3/genética , Humanos , Animais , Mitocôndrias/metabolismo , Senescência Celular , Feminino , Mamíferos/metabolismo , Estresse OxidativoRESUMO
Recent observations have revealed upregulation of H3K27cr in colorectal cancer (CRC) tissues; however, the underlying cause remains elusive. This study aimed to investigate the mechanism of H3K27cr upregulation and its roles in CRC metastasis. Clinically, our findings showed that H3K27cr served as a highly accurate diagnostic marker to distinguish CRC tissues from healthy controls. Elevated levels of LINC00887 and H3K27cr were associated with a poorer prognosis in CRC patients. Functionally, LINC00887 and H3K27cr facilitated the migration and invasion of CRC cells. Mechanistically, LINC00887 interacted with SIRT3 protein. Overexpressed of LINC00887 obstructed the enrichment of SIRT3 within GCN5 promoter, thereby elevating H3K27ac but not H3K27cr level within this region, subsequently activating GCN5 expression. This activation increased the global level of H3K27cr, promoting the enrichment of GCN5, H3K27cr, and YEATS2 within ETS1 promoter, activating ETS1 transcription and ultimately promoting the metastasis of CRC. The in vivo study demonstrated that inhibition of LINC00887 suppressed CRC metastasis, but this inhibitory effect was nullified when mice were treated with NaCr. In conclusion, our results confirmed the diagnostic biomarker potential of H3K27cr in individuals with CRC, and proposed a functional model to elucidate the involvement of LINC00887 in promoting CRC metastasis by elevating H3K27cr level.
Assuntos
Neoplasias Colorretais , Regulação Neoplásica da Expressão Gênica , Camundongos Nus , Proteína Proto-Oncogênica c-ets-1 , RNA Longo não Codificante , Fatores de Transcrição de p300-CBP , Humanos , Neoplasias Colorretais/patologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Proteína Proto-Oncogênica c-ets-1/metabolismo , Proteína Proto-Oncogênica c-ets-1/genética , Animais , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo , Fatores de Transcrição de p300-CBP/metabolismo , Fatores de Transcrição de p300-CBP/genética , Camundongos , Metástase Neoplásica , Linhagem Celular Tumoral , Masculino , Movimento Celular/genética , Feminino , Camundongos Endogâmicos BALB C , Sirtuína 3/metabolismo , Sirtuína 3/genética , Regiões Promotoras Genéticas/genética , Histonas/metabolismo , Pessoa de Meia-IdadeRESUMO
BACKGROUND: Empagliflozin (EMPA) has demonstrated efficacy in providing cardiovascular benefits in metabolic diseases. However, the direct effect of EMPA on autophagy in obesity-related cardiac dysfunction remains unclear. Therefore, this study aimed to determine changes in cardiac autophagy during diet-induced obesity and clarify the exact mechanism by which EMPA regulates autophagic pathways. METHODS: Male C57BL/6J mice were fed a 12-week high-fat diet (HFD) followed by 8 weeks of EMPA treatment. Body composition analysis and echocardiography were performed to evaluate metabolic alterations and cardiac function. Histological and immunofluorescence staining was used to evaluate potential enhancements in myocardial structure and biological function. Additionally, H9c2 cells were transfected with small interfering RNA targeting sirtuin 3 (SIRT3) and further treated with palmitic acid (PA) with or without EMPA. Autophagy-related targets were analyzed by western blotting and RTâqPCR. RESULTS: EMPA administration effectively ameliorated metabolic disorders and cardiac diastolic dysfunction in HFD-fed mice. EMPA prevented obesity-induced myocardial hypertrophy, fibrosis, and inflammation through the activation of SIRT3-mediated autophagosome formation. The upregulation of SIRT3 triggered by EMPA promoted the initiation of autophagy by activating AMP-activated protein kinase (AMPK) and Beclin1. Furthermore, activated SIRT3 contributed to the elongation of autophagosomes through autophagy-related 4B cysteine peptidase (ATG4B) and autophagy-related 5 (ATG5). CONCLUSIONS: EMPA promotes SIRT3-mediated autophagosome formation to alleviate damage to the cardiac structure and function of obese mice. Activated SIRT3 initiates autophagy through AMPK/Beclin1 and further stimulates elongation of the autophagosome membrane via ATG4B/ATG5. These results provide a new explanation for the cardioprotective benefits of EMPA in obesity.
Assuntos
Autofagossomos , Autofagia , Compostos Benzidrílicos , Dieta Hiperlipídica , Glucosídeos , Camundongos Endogâmicos C57BL , Obesidade , Sirtuína 3 , Animais , Glucosídeos/farmacologia , Compostos Benzidrílicos/farmacologia , Obesidade/tratamento farmacológico , Obesidade/complicações , Obesidade/metabolismo , Masculino , Camundongos , Autofagossomos/metabolismo , Autofagossomos/efeitos dos fármacos , Dieta Hiperlipídica/efeitos adversos , Autofagia/efeitos dos fármacos , Sirtuína 3/metabolismo , Sirtuína 3/genética , Miócitos Cardíacos/efeitos dos fármacos , Miócitos Cardíacos/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Linhagem Celular , Miocárdio/metabolismo , Miocárdio/patologia , Inibidores do Transportador 2 de Sódio-Glicose/farmacologiaRESUMO
BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an age-related disease severely affecting life quality with its prevalence rising as the population ages, yet there is still no effective treatment available. Cell therapy has emerged as a promising option for IPF, however, the absence of mature and stable animal models for IPF immunodeficiency hampers preclinical evaluations of human cell therapies, primarily due to rapid immune clearance of administered cells. This study aims to establish a reliable pulmonary fibrosis (PF) model in immunodeficient mice that supports autologous cell therapy and to investigate underlying mechanism. METHODS: We utilized thirty 5-week-old male NOD/SCID mice, categorizing them into three age groups: 12weeks, 32 weeks and 43 weeks, with 6 mice euthanized randomly from each cohort for lung tissue analysis. We assessed fibrosis using HE staining, Masson's trichrome staining, α-SMA immunohistochemistry and hydroxyproline content measurement. Further, ß-galactosidase staining and gene expression analysis of MMP9, TGF-ß1, TNF-α, IL-1ß, IL-6, IL-8, SOD1, SOD2, NRF2, SIRT1, and SIRT3 were performed. ELISA was employed to quantify protein levels of TNF-α, TGF-ß1, and IL-8. RESULTS: When comparing lung tissues from 32-week-old and 43-week-old mice to those from 12-week-old mice, we noted a marked increase in inflammatory infiltration, fibrosis severity, and hydroxyproline content, alongside elevated expression levels of α-SMA and MMP9. Notably, the degree of fibrosis intensified with age. Additionally, ß-galactosidase staining became more pronounced in older mice. Quantitative PCR analyses revealed age-related, increases in the expression of senescence markers (GLB1, P16, P21), and proinflammatory genes (TGF-ß1, TNF-α, IL-1ß, IL-6, and IL-8). Conversely, the expression of anti-oxidative stress-related genes (SOD1, SOD2, NRF2, SIRT1, and SIRT3) declined, showing statistically significant differences (*P < 0.05, **P < 0.01, ***P < 0.001). ELISA results corroborated these findings, indicating a progressive rise in the protein levels of TGF-ß1, TNF-α, and IL-8 as the mice aged. CONCLUSIONS: The findings suggest that NOD/SCID mice aged 32 weeks and 43 weeks effectively model pulmonary fibrosis in an elderly context, with the disease pathogenesis likely driven by age-associated inflammation and oxidative stress.
Assuntos
Envelhecimento , Modelos Animais de Doenças , Camundongos Endogâmicos NOD , Camundongos SCID , Sirtuína 1 , Animais , Camundongos , Masculino , Sirtuína 1/metabolismo , Sirtuína 1/genética , Pulmão/patologia , Pulmão/metabolismo , Fator de Crescimento Transformador beta1/metabolismo , Fator de Crescimento Transformador beta1/genética , Metaloproteinase 9 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/genética , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/genética , Fibrose Pulmonar Idiopática/genética , Fibrose Pulmonar Idiopática/patologia , Fibrose Pulmonar Idiopática/metabolismo , Interleucina-8/metabolismo , Interleucina-8/genética , Superóxido Dismutase-1/genética , Superóxido Dismutase-1/metabolismo , Superóxido Dismutase/metabolismo , Superóxido Dismutase/genética , Sirtuína 3/genética , Sirtuína 3/metabolismo , Hidroxiprolina/metabolismo , Interleucina-6/metabolismo , Interleucina-6/genética , Actinas/metabolismo , Actinas/genética , Interleucina-1beta/metabolismo , Interleucina-1beta/genética , Fibrose Pulmonar/genética , Fibrose Pulmonar/patologia , Fibrose Pulmonar/metabolismoRESUMO
OBJECTIVE: This study aimed to explore the expression and biological functions of SIRT3 in colorectal cancer cells (HCT-116), the impacts of sulforaphane on the ferroptosis of HCT-116 cells and the involvement of the SIRT3/AMPK/mTOR axis in those effects. METHODS: SIRT3-overexpressing (OE) and SIRT3-knockout (KO) cell lines were treated with different concentrations of sulforaphane, RSL-3, and IKE. Cell viability, intracellular ROS, MDA, iron levels, as well as mRNA and protein expressions of target genes were measured. RESULTS: SIRT3 expression in HCT-116 cells was increased by ferroptosis inducers and decreased by ferroptosis inhibitors. SIRT3 overexpression reduced cell viability and increased intracellular levels of ROS, MDA, and iron, whereas SIRT3 knockdown achieved the opposite effects. SIRT3 overexpression suppressed SLC7A11 expression and promoted the activation of AMPK/mTOR pathway. Restoration of SLC7A11 expression blocked the effects of SIRT3 on ferroptosis induction and cell viability inhibition. SIRT3 effects on cell viability and ferroptosis were antagonized by inhibitors of AMPK or mTOR. Moreover, sulforaphane triggered the ferroptosis of HCT-116 cells by activating the SIRT3/AMPK/mTOR axis. CONCLUSIONS: SIRT3 triggered SLC7A11-mediated ferroptosis in HCT-116 cells, reducing cell viability by activating the AMPK/mTOR pathway, and sulforaphane targets it to inhibit colorectal cancer.
Assuntos
Proteínas Quinases Ativadas por AMP , Neoplasias Colorretais , Ferroptose , Isotiocianatos , Transdução de Sinais , Sirtuína 3 , Sulfóxidos , Serina-Treonina Quinases TOR , Humanos , Isotiocianatos/farmacologia , Sirtuína 3/metabolismo , Sirtuína 3/genética , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Ferroptose/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células HCT116 , Anticarcinógenos/farmacologia , Sobrevivência Celular/efeitos dos fármacosRESUMO
Atrial fibrosis is associated with the occurrence of atrial fibrillation (AF) and regulated by the transforming growth factor-ß1 (TGF-ß1)/Smad2/3 signalling pathway. Unfortunately, the mechanisms of regulation of TGF-ß1/Smad2/3-induced atrial fibrosis and vulnerability to AF remain still unknown. Previous studies have shown that sirtuin3 (SIRT3) sulfhydration has strong anti-fibrotic effects. We hypothesised that SIRT3 sulfhydration inhibits angiotensin II (Ang-II)-induced atrial fibrosis via blocking the TGF-ß1/Smad2/3 signalling pathway. In this study, we found that SIRT3 expression was decreased in the left atrium of patients with AF compared to that in those with sinus rhythm (SR). In vitro, SIRT3 knockdown by small interfering RNA significantly expanded Ang-II-induced atrial fibrosis and TGF-ß1/Smad2/3 signalling pathway activation, whereas supplementation with Sodium Hydrosulfide (NaHS, exogenous hydrogen sulfide donor and sulfhydration agonist) and SIRT3 overexpression using adenovirus ameliorated Ang-II-induced atrial fibrosis. Moreover, we observed suppression of the TGF-ß1/Smad2/3 pathway when Ang-II was combined with NaHS treatment, and the effect of this co-treatment was consistent with that of Ang-II combined with LY3200882 (Smad pathway inhibitor) on reducing atrial fibroblast proliferation and cell migration in vitro. Supplementation with dithiothreitol (DTT, a sulfhydration inhibitor) and adenovirus SIRT3 shRNA blocked the ameliorating effect of NaHS and AngII co-treatment on atrial fibrosis in vitro. Finally, continued treatment with NaHS in rats ameliorated atrial fibrosis and remodelling, and further improved AF vulnerability induced by Ang-II, which was reversed by DTT and adenovirus SIRT3 shRNA, suggesting that SIRT3 sulfhydration might be a potential therapeutic target in atrial fibrosis and AF.
Assuntos
Angiotensina II , Fibrilação Atrial , Fibrose , Átrios do Coração , Sulfeto de Hidrogênio , Transdução de Sinais , Sirtuína 3 , Proteína Smad2 , Proteína Smad3 , Fator de Crescimento Transformador beta1 , Idoso , Animais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ratos , Angiotensina II/farmacologia , Fibrilação Atrial/metabolismo , Fibrilação Atrial/patologia , Fibrilação Atrial/prevenção & controle , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/metabolismo , Átrios do Coração/patologia , Sulfeto de Hidrogênio/farmacologia , Sulfeto de Hidrogênio/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Sirtuína 3/metabolismo , Sirtuína 3/genética , Proteína Smad2/metabolismo , Proteína Smad3/metabolismo , Fator de Crescimento Transformador beta1/metabolismoRESUMO
BACKGROUND: Hyperglycemia-induced neuroinflammation significantly contributes to diabetic neuropathic pain (DNP), but the underlying mechanisms remain unclear. OBJECTIVE: To investigate the role of Sirt3, a mitochondrial deacetylase, in hyperglycemia-induced neuroinflammation and DNP and to explore potential therapeutic interventions. METHOD AND RESULTS: Here, we found that Sirt3 was downregulated in spinal dorsal horn (SDH) of diabetic mice by RNA-sequencing, which was further confirmed at the mRNA and protein level. Sirt3 deficiency exacerbated hyperglycemia-induced neuroinflammation and DNP by enhancing microglial aerobic glycolysis in vivo and in vitro. Overexpression of Sirt3 in microglia alleviated inflammation by reducing aerobic glycolysis. Mechanistically, high-glucose stimulation activated Akt, which phosphorylates and inactivates FoxO1. The inactivation of FoxO1 diminished the transcription of Sirt3. Besides that, we also found that hyperglycemia induced Sirt3 degradation via the mitophagy-lysosomal pathway. Blocking Akt activation by GSK69093 or metformin rescued the degradation of Sirt3 protein and transcription inhibition of Sirt3 mRNA, which substantially diminished hyperglycemia-induced inflammation. Metformin in vivo treatment alleviated neuroinflammation and diabetic neuropathic pain by rescuing hyperglycemia-induced Sirt3 downregulation. CONCLUSION: Hyperglycemia induces metabolic reprogramming and inflammatory activation in microglia through the regulation of Sirt3 transcription and degradation. This novel mechanism identifies Sirt3 as a potential drug target for treating DNP.
Assuntos
Diabetes Mellitus Experimental , Neuropatias Diabéticas , Regulação para Baixo , Glicólise , Hiperglicemia , Camundongos Endogâmicos C57BL , Microglia , Sirtuína 3 , Animais , Sirtuína 3/metabolismo , Sirtuína 3/genética , Camundongos , Glicólise/efeitos dos fármacos , Glicólise/fisiologia , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/fisiologia , Hiperglicemia/metabolismo , Microglia/metabolismo , Microglia/efeitos dos fármacos , Masculino , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/complicações , Neuropatias Diabéticas/metabolismo , Inflamação/metabolismo , Doenças Neuroinflamatórias/metabolismo , Doenças Neuroinflamatórias/etiologia , Metformina/farmacologiaRESUMO
The neuronal excitotoxicity that follows reoxygenation after a hypoxic period may contribute to epilepsy, Alzheimer's disease, Parkinson's disease and various disorders that are related to inadequate supplement of oxygen in neurons. Therefore, counteracting the deleterious effects of post-hypoxic stress is an interesting strategy to treat a large spectrum of neurodegenerative diseases. Here, we show that the expression of the key telomere protecting protein Trf2 decreases in the brain of mice submitted to a post-hypoxic stress. Moreover, downregulating the expression of Terf2 in hippocampal neural cells of unchallenged mice triggers an excitotoxicity-like phenotype including glutamate overexpression and behavioral alterations while overexpressing Terf2 in hippocampal neural cells of mice subjected to a post-hypoxic treatment prevents brain damages. Moreover, Terf2 overexpression in culture neurons counteracts the oxidative stress triggered by glutamate. Finally, we provide evidence that the effect of Terf2 downregulation on excitotoxicity involves Sirt3 repression leading to mitochondrial dysfunction. We propose that increasing the level of Terf2 expression is a potential strategy to reduce post-hypoxic stress damages.
Assuntos
Neurônios , Sirtuína 3 , Proteína 2 de Ligação a Repetições Teloméricas , Animais , Camundongos , Proteína 2 de Ligação a Repetições Teloméricas/metabolismo , Proteína 2 de Ligação a Repetições Teloméricas/genética , Sirtuína 3/metabolismo , Sirtuína 3/genética , Neurônios/metabolismo , Neurônios/patologia , Hipocampo/metabolismo , Hipocampo/patologia , Estresse Oxidativo , Mitocôndrias/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Hipóxia/metabolismo , Ácido Glutâmico/metabolismo , Telômero/metabolismo , Telômero/genética , MasculinoRESUMO
AIMS: Postoperative delirium (POD) is a common neurological complication in elderly patients after anesthesia/surgery. The main purpose of this study is to explore the effect of circRNA-targeted miRNA regulating SIRT3 on mitochondrial function through ceRNA mechanism under the surgical model of tibial fracture and to further explore the potential mechanism of postoperative delirium mediated by circRNA, so as to provide new ideas for clinical diagnosis and prevention of POD. METHODS: The surgical model of tibial fracture under sevoflurane anesthesia caused acute delirium-like behavior in elderly mice. We observed that the decrease of SIRT3 and mitochondrial dysfunction was related to POD, and miRNA and circRNA (circRNA_34414) related to SIRT3 were further studied. Through luciferase and RAP, we observed that circRNA_34414, as a miRNA sponge, was involved in the regulation of SIRT3 expression. RESULTS: Postoperative delirium in elderly mice showed decreased expression of hippocampal circRNA_34414, increased expression of miR-6960-5p, decreased expression of SIRT3, and impaired mitochondrial membrane potential. Overexpression of circRNA_34414, or knockdown of miR-6960-5p, or overexpression of SIRT3 in hippocampal CA1 glutamatergic neurons significantly upregulated hippocampal SIRT3 expression, increased mitochondrial membrane potential levels, and significantly ameliorated postoperative delirium in aged mice; CircRNA_34414 ameliorates postoperative delirium in mice, possibly by targeting miR-6960-5p to upregulate SIRT3. CONCLUSIONS: CircRNA_34414 is involved in the improvement of postoperative delirium induced by anesthesia/surgery by upregulating SIRT3 via sponging miR-6960-5p.
Assuntos
Delírio , MicroRNAs , Neurônios , Complicações Pós-Operatórias , RNA Circular , Sirtuína 3 , Animais , Sirtuína 3/metabolismo , Sirtuína 3/genética , Delírio/metabolismo , Camundongos , MicroRNAs/metabolismo , MicroRNAs/genética , RNA Circular/metabolismo , Neurônios/metabolismo , Neurônios/efeitos dos fármacos , Masculino , Complicações Pós-Operatórias/metabolismo , Região CA1 Hipocampal/metabolismo , Região CA1 Hipocampal/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Fraturas da Tíbia/cirurgia , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Potencial da Membrana Mitocondrial/fisiologiaRESUMO
Understanding the role of iron in ethanol-derived hepatic stress could help elucidate the efficacy of dietary or clinical interventions designed to minimize liver damage from chronic alcohol consumption. We hypothesized that normal levels of iron are involved in ethanol-derived liver damage and reduced dietary iron intake would lower the damage caused by ethanol. We used a pair-fed mouse model utilizing basal Lieber-DeCarli liquid diets for 22 weeks to test this hypothesis. In our mouse model, chronic ethanol exposure led to mild hepatic stress possibly characteristic of early-stage alcoholic liver disease, seen as increases in liver-to-body weight ratios. Dietary iron restriction caused a slight decrease in non-heme iron and ferritin (FeRL) expression while it increased transferrin receptor 1 (TfR1) expression without changing ferroportin 1 (FPN1) expression. It also elevated protein lysine acetylation to a more significant level than in ethanol-fed mice under normal dietary iron conditions. Interestingly, iron restriction led to an additional reduction in nicotinamide adenine dinucleotide (NAD+) and NADH levels. Consistent with this observation, the major mitochondrial NAD+-dependent deacetylase, NAD-dependent deacetylase sirtuin-3 (SIRT3), expression was significantly reduced causing increased protein lysine acetylation in ethanol-fed mice at normal and low-iron conditions. In addition, the detection of superoxide dismutase 1 and 2 levels (SOD1 and SOD2) and oxidative phosphorylation (OXPHOS) complex activities allowed us to evaluate the changes in antioxidant and energy metabolism regulated by ethanol consumption at normal and low-iron conditions. We observed that the ethanol-fed mice had mild liver damage associated with reduced energy and antioxidant metabolism. On the other hand, iron restriction may exacerbate certain activities of ethanol further, such as increased protein lysine acetylation and reduced antioxidant metabolism. This metabolic change may prove a barrier to the effectiveness of dietary reduction of iron intake as a preventative measure in chronic alcohol consumption.
Assuntos
Antioxidantes , Metabolismo Energético , Etanol , Animais , Camundongos , Acetilação/efeitos dos fármacos , Metabolismo Energético/efeitos dos fármacos , Antioxidantes/metabolismo , Masculino , Ferro/metabolismo , Superóxido Dismutase-1/metabolismo , Superóxido Dismutase-1/genética , Superóxido Dismutase/metabolismo , Lisina/metabolismo , Fígado/metabolismo , Fígado/efeitos dos fármacos , Receptores da Transferrina/metabolismo , Sirtuína 3/metabolismo , Sirtuína 3/genética , NAD/metabolismo , Ferritinas/metabolismo , Proteínas de Transporte de Cátions/metabolismo , Proteínas de Transporte de Cátions/genética , Estresse Oxidativo/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Hepatopatias Alcoólicas/metabolismo , Hepatopatias Alcoólicas/patologia , Hepatopatias Alcoólicas/etiologiaRESUMO
OBJECTIVES: The mitochondrial deacetylase sirtuin-3 (SIRT3) is necessary for the increased bone resorption and enhanced function of mitochondria in osteoclasts that occur with advancing age; how SIRT3 drives bone resorption remains elusive. METHODS: To determine the role of SIRT3 in osteoclast mitochondria, we used mice with conditional loss of Sirt3 in osteoclast lineage and mice with germline deletion of either Sirt3 or its known target Pink1. RESULTS: SIRT3 stimulates mitochondrial quality in osteoclasts in a PINK1-independent manner, promoting mitochondrial activity and osteoclast maturation and function, thereby contributing to bone loss in female but not male mice. Quantitative analyses of global proteomes and acetylomes revealed that deletion of Sirt3 dramatically increased acetylation of osteoclast mitochondrial proteins, particularly ATPase inhibitory factor 1 (ATPIF1), an essential protein for mitophagy. Inhibition of mitophagy via mdivi-1 recapitulated the effect of deletion of Sirt3 or Atpif1 in osteoclast formation and mitochondrial function. CONCLUSIONS: Decreasing mitophagic flux in osteoclasts may be a promising pharmacotherapeutic approach to treat osteoporosis in older adults.
Assuntos
Envelhecimento , Reabsorção Óssea , Mitocôndrias , Proteínas Mitocondriais , Osteoclastos , Sirtuína 3 , Animais , Sirtuína 3/metabolismo , Sirtuína 3/genética , Osteoclastos/metabolismo , Camundongos , Feminino , Envelhecimento/metabolismo , Reabsorção Óssea/metabolismo , Masculino , Proteínas Mitocondriais/metabolismo , Proteínas Mitocondriais/genética , Mitocôndrias/metabolismo , Acetilação , Mitofagia , Camundongos Knockout , Camundongos Endogâmicos C57BL , Proteínas Quinases/metabolismo , Proteínas Quinases/genética , Osteoporose/metabolismo , Osteoporose/patologiaRESUMO
Cisplatin (CDDP) often leads to kidney impairment, limiting its effectiveness in cancer treatment. The lack of mitophagy in proximal tubules exacerbates this issue. Hence, targeting SIRT-3 and PGC1-α shows promise in mitigating CDDP-induced kidney damage. The potential renoprotective effects of linagliptin, however, remain poorly understood. This study represents the first exploration of linagliptin's impact on CDDP-induced kidney impairment in rats, emphasizing its potential role in mitophagic pathways. The experiment involved four rat groups: Group (I) received saline only, Group (II) received a single intraperitoneal injection of CDDP at 6 mg/kg. Groups (III) and (IV) received linagliptin at 6 and 10 mg/kg p.o., respectively, seven days before CDDP administration, continuing for an additional four days. Various parameters, including renal function tests, oxidative stress, TNF-α, IL-1ß, IL-6, PGC-1α, FOXO-3a, p-ERK1, and the gene expression of SIRT-3 and P62 in renal tissue, were assessed. Linagliptin improved renal function, increased antioxidant enzyme activity, and decreased IL-1ß, TNF-α, and IL-6 expression. Additionally, linagliptin significantly upregulated PGC-1α and PINK-1/Parkin-2 expression while downregulating P62 expression. Moreover, linagliptin activated FOXO-3a and SIRT-3, suggesting a potential enhancement of mitophagy. Linagliptin demonstrated a positive impact on various factors related to kidney health in the context of CDDP-induced impairment. These findings suggest a potential role for linagliptin in improving cancer treatment outcomes. Clinical trials are warranted to further investigate and validate its efficacy in a clinical setting.
Assuntos
Cisplatino , Linagliptina , Mitofagia , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Ubiquitina-Proteína Ligases , Animais , Linagliptina/farmacologia , Cisplatino/toxicidade , Mitofagia/efeitos dos fármacos , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Masculino , Ratos , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Sirtuína 3/metabolismo , Sirtuína 3/genética , Proteínas Quinases/metabolismo , Rim/efeitos dos fármacos , Rim/metabolismo , Rim/patologia , Ratos Wistar , Antineoplásicos/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Nefropatias/induzido quimicamente , Nefropatias/prevenção & controle , Nefropatias/metabolismo , Nefropatias/patologia , SirtuínasRESUMO
The accumulating evidence has made it clear that iron overload is a crucial mechanism in bone loss. Protocatechualdehyde (PCA) has also been used to prevent osteoporosis in recent years. Whether PCA can reverse the harmful effects of iron overload on bone mass in aged rats is still unknown. Therefore, this study aimed to assess the role of PCA in iron overload-induced bone loss in senile rats. In the aged rat model, we observed that iron overload affects bone metabolism and bone remodeling, manifested by bone loss and decreased bone mineral density. The administration of PCA effectively mitigated the detrimental effects caused by iron overload, and concomitant reduction in MDA serum levels and elevation of SOD were noted. In addition, PCA-treated rats were observed to have significantly increased bone mass and elevated expression of SIRT3ï¼BMP2ï¼SOD2 and reduced expression of TNF-α in bone tissue. We also observed that PCA was able to reduce oxidative stress and inflammation and restore the imbalance in bone metabolism. When MC3T3-E1 and RAW264.7 cells induced osteoblast and osteoclasts differentiation, PCA intervention could significantly recover the restriction of osteogenic differentiation and up-regulation of osteoclast differentiation treated by iron overload. Further, by detecting changes in ROS, SOD, MDA, expression of SIRT3 and mitochondrial membrane potentials, we confirm that the damage caused to cells by iron overload is associated with decreased SIRT3 activity, and that 3-TYP have similar effects on oxidative stress caused by FAC. In conclusion, PCA can resist iron overload-induced bone damage by improving SIRT3 activity, anti-inflammatory and anti-oxidative stress.
Assuntos
Sobrecarga de Ferro , Estresse Oxidativo , Animais , Estresse Oxidativo/efeitos dos fármacos , Sobrecarga de Ferro/metabolismo , Camundongos , Ratos , Masculino , Células RAW 264.7 , Ratos Sprague-Dawley , Osteoclastos/efeitos dos fármacos , Osteoclastos/metabolismo , Sirtuína 3/metabolismo , Sirtuína 3/genética , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Osteoporose/metabolismo , Osteoporose/etiologia , Osteoporose/tratamento farmacológico , Benzaldeídos/farmacologia , Benzaldeídos/uso terapêutico , Inflamação , Osteogênese/efeitos dos fármacos , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Densidade Óssea/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Envelhecimento , Modelos Animais de Doenças , Superóxido Dismutase/metabolismo , SirtuínasRESUMO
Sodium-glucose cotransporter-2 inhibitors (SGLT2i) have a variety of cardiovascular and renoprotective effects and have been developed as novel agents for the treatment of heart failure. However, the beneficial mechanisms of SGLT2i on cardiac tissue need to be investigated further. In this study, we established a mouse model of acute myocardial infarction (AMI) using coronary artery constriction surgery and investigated the role of dapagliflozin (DAPA) in protecting cardiomyocytes from hypoxic injury induced by AMI. In vitro experiments were done using hypoxic cultured H9c2 ventricular cells to verify this potential mechanism. Expression of the SIRT family and related genes and proteins was verified by qPCR, Western blotting and immunofluorescence staining, and the intrinsic potential mechanism of cardiomyocyte death due to AMI and hypoxia was comprehensively investigated by RNA sequencing. The RNA sequencing results of cardiomyocytes from AMI mice showed that the SIRT family may be mainly involved in the mechanisms of hypoxia-induced cardiomyocyte death. In vitro hypoxia-induced ventricular cells showed the role of dapagliflozin in conferring resistance to hypoxic injury in cardiomyocytes. It showed that SIRT1/3/6 were downregulated in H9c2 cells in a hypoxic environment, and the addition of dapagliflozin significantly increased the gene and protein expression of SIRT1, 3 and 6. We then verified the underlying mechanisms induced by dapagliflozin in hypoxic cardiomyocytes using RNA-seq, and found that dapagliflozin upregulated the hypoxia-induced gene downregulation, which includes ESRRA, EPAS1, AGTRAP, etc., that associated with SIRTs-related and apoptosis-related signaling to prevent H9c2 cell death. This study provides laboratory data for SGLT2i dapagliflozin treatment of AMI and confirms that dapagliflozin can be used to treat hypoxia-induced cellular necrosis in cardiomyocytes, in which SIRT1 and SIRT3 may play an important role. This opens up further opportunities for SGLT2i in the treatment of heart disease.
Assuntos
Compostos Benzidrílicos , Glucosídeos , Infarto do Miocárdio , Miócitos Cardíacos , Transdução de Sinais , Sirtuína 1 , Inibidores do Transportador 2 de Sódio-Glicose , Glucosídeos/farmacologia , Glucosídeos/uso terapêutico , Animais , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/efeitos dos fármacos , Compostos Benzidrílicos/farmacologia , Inibidores do Transportador 2 de Sódio-Glicose/farmacologia , Camundongos , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/tratamento farmacológico , Infarto do Miocárdio/patologia , Sirtuína 1/metabolismo , Sirtuína 1/genética , Transdução de Sinais/efeitos dos fármacos , Masculino , Sirtuína 3/metabolismo , Sirtuína 3/genética , Sirtuínas/metabolismo , Sirtuínas/genética , Linhagem Celular , Camundongos Endogâmicos C57BL , Modelos Animais de Doenças , Hipóxia Celular/efeitos dos fármacos , Ratos , Apoptose/efeitos dos fármacosRESUMO
OBJECTIVE: The aim of this study was to investigate whether ASA VI controls osteoarthritis (OA) by regulating mitochondrial function. METHODS: Primary chondrocytes were isolated and cultured from rat knee joints. The chondrocytes were treated with ASA VI and interleukin-1ß (IL-1ß) to simulate the inflammatory environment of OA. Cell viability, apoptosis, inflammatory cytokine levels, and extracellular matrix (ECM) component levels were assessed. Mitochondrial function, including ATP levels, mitochondrial membrane potential, reactive oxygen species (ROS) levels, and mitochondrial DNA content, was evaluated. The expression of Sirtuin 3 (Sirt3), a key regulator of mitochondrial homeostasis, was examined. Additionally, a rat OA model was established by destabilizing the medial meniscus, and the effects of ASA VI on cartilage degeneration were assessed. RESULTS: ASA VI treatment improved cell viability, reduced apoptosis, and decreased IL-6 and TNF-α levels in IL-1ß-induced chondrocytes. ASA VI also upregulated Collagen II and Aggrecan expression, while downregulating ADAMTS5 and MMP-13 expression. Furthermore, ASA VI mitigated IL-1ß-induced mitochondrial dysfunction by increasing ATP levels, restoring mitochondrial membrane potential, reducing ROS production, and preserving mitochondrial DNA content. These effects were accompanied by the activation of Sirt3. In the rat OA model, ASA VI treatment increased Sirt3 expression and alleviated cartilage degeneration. CONCLUSION: ASA VI exerts chondroprotective and anti-inflammatory effects on IL-1ß-induced chondrocytes by improving mitochondrial function through Sirt3 activation. ASA VI also attenuates cartilage degeneration in a rat OA model. These findings suggest that ASA VI may be a potential therapeutic agent for the treatment of osteoarthritis by targeting mitochondrial dysfunction.
Assuntos
Condrócitos , Homeostase , Mitocôndrias , Osteoartrite , Saponinas , Sirtuína 3 , Animais , Masculino , Camundongos , Ratos , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Apoptose/efeitos dos fármacos , Cartilagem Articular/patologia , Cartilagem Articular/metabolismo , Cartilagem Articular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Condrócitos/efeitos dos fármacos , Condrócitos/metabolismo , Citocinas/metabolismo , Modelos Animais de Doenças , Interleucina-1beta/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Osteoartrite/tratamento farmacológico , Osteoartrite/metabolismo , Osteoartrite/patologia , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Sirtuína 3/metabolismo , Sirtuína 3/genética , Saponinas/farmacologiaRESUMO
Glioblastoma multiforme (GBM) is a highly malignant brain tumor, and glioblastoma stem cells (GSCs) are the primary cause of GBM heterogeneity, invasiveness, and resistance to therapy. Sirtuin 3 (SIRT3) is mainly localized in the mitochondrial matrix and plays an important role in maintaining GSC stemness through cooperative interaction with the chaperone protein tumor necrosis factor receptor-associated protein 1 (TRAP1) to modulate mitochondrial respiration and oxidative stress. The present study aimed to further elucidate the specific mechanisms by which SIRT3 influences GSC stemness, including whether SIRT3 serves as an autophagy substrate and the mechanism of SIRT3 degradation. We first found that SIRT3 is enriched in CD133+ GSCs. Further experiments revealed that in addition to promoting mitochondrial respiration and reducing oxidative stress, SIRT3 maintains GSC stemness by epigenetically regulating CD133 expression via succinate. More importantly, we found that SIRT3 is degraded through the autophagy-lysosome pathway during GSC differentiation into GBM bulk tumor cells. GSCs are highly dependent on glutamine for survival, and in these cells, we found that glutamine deprivation triggers autophagic SIRT3 degradation to restrict CD133 expression, thereby disrupting the stemness of GSCs. Together our results reveal a novel mechanism by which SIRT3 regulates GSC stemness. We propose that glutamine restriction to trigger autophagic SIRT3 degradation offers a strategy to eliminate GSCs, which combined with other treatment methods may overcome GBM resistance to therapy as well as relapse.