Dataset Information

Dihydromyricetin Protects Against Gentamicin-Induced Ototoxicity via PGC-1?/SIRT3 Signaling in vitro.

ABSTRACT: Aminoglycoside-induced ototoxicity can have a major impact on patients' quality of life and social development problems. Oxidative stress affects normal physiologic functions and has been implicated in aminoglycoside-induced inner ear injury. Excessive accumulation of reactive oxygen species (ROS) damages DNA, lipids, and proteins in cells and induces their apoptosis. Dihydromyricetin (DHM) is a natural flavonol with a wide range of health benefits including anti-inflammatory, antitumor, and antioxidant effects; however, its effects and mechanism of action in auditory hair cells are not well understood. The present study investigated the antioxidant mechanism and anti-ototoxic potential of DHM using House Ear Institute-Organ of Corti (HEI-OC)1 auditory cells and cochlear explant cultures prepared from Kunming mice. We used gentamicin to establish aminoglycoside-induced ototoxicity models. Histological and physiological analyses were carried out to determine DHM's pharmacological effects on gentamicin-induced ototoxicity. Results showed DHM contributes to protecting cells from apoptotic cell death by inhibiting ROS accumulation. Western blotting and quantitative RT-PCR analyses revealed that DHM exerted its otoprotective effects by up-regulating levels of peroxisome proliferator activated receptor ?-coactivator (PGC)-1? and Sirtuin (SIRT)3. And the role of PGC-1? and SIRT3 in the protective effects of DHM was evaluated by pharmacologic inhibition of these factors using SR-18292 and 3-(1H-1,2,3-triazol-4-yl) pyridine, respectively, which indicated DHM's protective effect was dependent on activation of the PGC-1?/SIRT3 signaling. Our study is the first report to identify DHM as a potential otoprotective drug and provides a basis for the prevention and treatment of hearing loss caused by aminoglycoside antibiotic-induced oxidative damage to auditory hair cells.

SUBMITTER: Han H

PROVIDER: S-EPMC7399350 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Dihydromyricetin Protects Against Gentamicin-Induced Ototoxicity via PGC-1α/SIRT3 Signaling <i>in vitro</i>.

Han Hezhou H Dong Yaodong Y Ma Xiulan X

Frontiers in cell and developmental biology 20200728

Aminoglycoside-induced ototoxicity can have a major impact on patients' quality of life and social development problems. Oxidative stress affects normal physiologic functions and has been implicated in aminoglycoside-induced inner ear injury. Excessive accumulation of reactive oxygen species (ROS) damages DNA, lipids, and proteins in cells and induces their apoptosis. Dihydromyricetin (DHM) is a natural flavonol with a wide range of health benefits including anti-inflammatory, antitumor, and ant ...[more]

PMID: 32850822

Similar Datasets

Project description:BackgroundTo study the protective effects of delayed remote ischemic preconditioning (RIPC) against spinal cord ischemia-reperfusion injury (SCIRI) in mice and determine whether SIRT3 is involved in this protection and portrayed its upstream regulatory mechanisms.MethodsIn vivo, WT or SIRT3 global knockout (KO) mice were exposed to right upper and lower limbs RIPC or sham ischemia. After 24 h, the abdominal aorta was clamped for 20 min, then re-perfused for 3 days. The motor function of mice, number of Nissl bodies, apoptotic rate of neurons, and related indexes of oxidative stress in the spinal cord were measured to evaluate for neuroprotective effects. The expression and correlation of SIRT3 and NMDAR were detected by WB and immunofluorescence. In vitro, primary neurons were exacted and OGD/R was performed to simulate SCIRI in vivo. Neuronal damage was assessed by observing neuron morphology, detecting LDH release ratio, and flow cytometry to analyze the apoptosis. MnSOD and CAT enzyme activities, GSH and ROS level were also measured to assess neuronal antioxidant capacity. NMDAR-AMPK-PGC-1α signaling was detected by WB to portray upstream regulatory mechanisms of RIPC regulating SIRT3.ResultsCompared to the SCIRI mice without RIPC, mice with RIPC displayed improved motor function recovery, a reduced neuronal loss, and enhanced antioxidant capacity. To the contrary, the KO mice did not exhibit any effect of RIPC-induced neuroprotection. Similar results were observed in vitro. Further analyses with spinal cord tissues or primary neurons detected enhanced MnSOD and CAT activities, as well as increased GSH level but decreased MDA or ROS production in the RIPC + I/R mice or NMDA + OGD/R neurons. However, these changes were completely inhibited by the absence of SIRT3. Additionally, NMDAR-AMPK-PGC-1α signaling was activated to upregulate SIRT3 levels, which is essential for RIPC-mediated neuroprotection.ConclusionsRIPC enhances spinal cord ischemia tolerance in a SIRT3-dependent manner, and its induced elevated SIRT3 levels are mediated by the NMDAR-AMPK-PGC-1α signaling pathway. Combined therapy targeting SIRT3 is a promising direction for treating SCIRI.

Project description:BackgroundNeuroinflammation and immune responses occurring minutes to hours after stroke are associated with brain injury after acute ischemic stroke (AIS). PPARγ coactivator-1α (PGC-1α), as a master coregulator of gene expression in mitochondrial biogenesis, was found to be transiently upregulated in microglia after AIS. However, the role of microglial PGC-1α in poststroke immune modulation remains unknown.MethodsPGC-1α expression in microglia from human and mouse brain samples following ischemic stroke was first determined. Subsequently, we employed transgenic mice with microglia-specific overexpression of PGC-1α for middle cerebral artery occlusion (MCAO). The morphology and gene expression profile of microglia with PGC-1α overexpression were evaluated. Downstream inflammatory cytokine production and NLRP3 activation were also determined. ChIP-Seq analysis was performed to detect PGC-1α-binding sites in microglia. Autophagic and mitophagic activity was further monitored by immunofluorescence staining. Unc-51-like autophagy activating kinase 1 (ULK1) expression was evaluated under the PGC-1α interaction with ERRα. Finally, pharmacological inhibition and genomic knockdown of ULK1 were performed to estimate the role of ULK1 in mediating mitophagic activity after ischemic stroke.ResultsPGC-1α expression was shortly increased after ischemic stroke, not only in human brain samples but also in mouse brain samples. Microglia-specific PGC-1α overexpressing mice exhibited significantly decreased neurologic deficits after ischemic injury, with reduced NLRP3 activation and proinflammatory cytokine production. ChIP-Seq analysis and KEGG pathway analysis revealed that mitophagy was significantly enhanced. PGC-1α significantly promoted autophagic flux and induced autolysosome formation. More specifically, the autophagic clearance of mitochondria was enhanced by PGC-1α regulation, indicating the important role of mitophagy. Pharmacological inhibition or knockdown of ULK1 expression impaired autophagic/mitophagic activity, thus abolishing the neuroprotective effects of PGC-1α.ConclusionsMechanistically, in AIS, PGC-1α promotes autophagy and mitophagy through ULK1 and reduces NLRP3 activation. Our findings indicate that microglial PGC-1α may be a promising therapeutic target for AIS.

Project description:Background/Aims:Increasing evidence have associated mitochondrial dysfunction and reactive oxygen species (ROS) generation to neuron loss in multiple sclerosis (MS). PGC-1α regulates mitochondrial biogenesis and respiration and plays a pivotal role in modulating ROS levels. Here, we investigated the potential function of peroxisome proliferator-activated receptor-γ co-activator-1α (PGC-1α) in the mammalian MS disease model, EAE experimental autoimmune encephalomyelitis (EAE). Methods:We used WT mice to evaluate the change of PGC during the course of EAE. The transgenic mice with neuron-specific overexpression of PGC-1α was applied to explore how PGC1 in neuron affects EAE outcome. A neuronal cell line of lentivirus transfection leading to PGC-1α markedly increased was applied to verify the protective effects of PGC1 in neurons. RNA-seq was employed to explore the potential target genes and signaling pathways. Results: We observed that PGC-1α were decreased at 13d, continuously decreased at 20d, then mildly increased at 30d in wild-type (WT) EAE mice, which is accompanied with alterations of mitochondrial antioxidants SOD2, Prx3, Trx2 and UCP4,5. Our study revealed that PGC-1αf/f Eno2-Cre mice improved EAE clinical symptoms, ameliorated inflammation and demyelination in spinal cords, increased mitochondrial antioxidants SOD2, Prx3, Trx2 and UCPs, reduced the production of ROS and inhibited the apoptotic pathways. In addition, PGC-1αf/f Eno2-Cre mice showed decreased apoptotic neurons compared with the WT EAE mice. In vitro, overexpressing PGC-1α by lentivirus transfection revealed similar results with that of in vivo by using NSC-34 cells treated with 1mg/ml lipopolysaccharide (LPS). Furthermore, RNA-seq analysis showed that apoptotic processes were significantly enriched in the top 10 significant GO terms of differentially expressed (DE) gene and apotosis pathway was significantly enriched in KEGG pathway analysis. Conclusion: Taken together, our findings indicate that upregulation of neuronal PGC-1α protected neuron apotosis in EAE and in vitro.

Project description:AimsPreventing mitochondrial dysfunction and enhancing mitochondrial health and biogenesis is a crucial therapeutic approach to ameliorate injury following acute myocardial infarction. Although the antioxidant role of melatonin against ischemia/reperfusion injury has been reported, the exact mechanism of protection, in vivo, remains poorly understood. This study aims to identify and elaborate upon mechanism of melatonin protection of rat cardiac mitochondria against acute myocardial infarction.Main methodsRats were pre-treated with melatonin (10 mg/kg body weight (b.w.); intraperitoneally, i.p.) before isoproterenol bitartrate (ISO) administration (25 mg/kg body weight (b.w.) subcutaneously,s.c.) and their effect on rat heart mitochondrial structure and function was studied. Biochemical changes in activity of biomarkers of oxidative stress, antioxidant enzymes as well as Krebs' cycle enzymes were analyzed. Gene expression studies and Isothermal titration calorimetric studies with pure catalase and ISO were also carried out.Key findingsMelatonin was shown to reduce ISO induced oxidative stress, by stimulating superoxide dismutase activity and removing the inhibition of Krebs' cycle enzymes. Herein we report for the first time in rat model that melatonin activates the SIRT1-PGC-1α-SIRT3 signaling pathways after ISO administration, which ultimately induces mitochondrial biogenesis. Melatonin exhibited significant protection of mitochondrial architecture and topology along with increased calcium ion permeability and reactive oxygen species (ROS) generation induced by ISO. Isothermal calorimetric studies revealed that melatonin binds to ISO molecules and sequesters them from the reaction thereby limiting their interaction with catalase along with occupying the binding sites of catalase themselves.SignificanceActivation of SIRT1-PGC-1α-SIRT3 pathway by melatonin along with its biophysical properties prevents ISO induced mitochondrial injury in rat heart.

Project description:BackgroundMitochondrial dysfunction has been implicated in the pathogenesis of ischemic heart disease, exacerbating cardiomyocytes injury in myocardial infarction (MI). Peroxisome proliferator-activated receptor gamma co-activator (PGC-1α) has been recognized as the key regulator of mitochondrial biogenesis and energy metabolism. Yiqihuoxue decoction (YQHX), a Traditional Chinese Medicine (TCM) prescription, can prevent and treat ischemic heart disease. However, the mechanisms of YQHX on PGC-1α expression in the ischemic heart have remained unclear.MethodsMyocardial ischemia rat model and ischemia/hypoxia injury model in the cardiomyocytes were used to minic human cardiovascular disease. Rats were randomly assigned into 4 groups: Sham, Model, YQHX (8.2 g/kg) and Trimetazidine (10 mg/kg) group. 28 days after MI, cardiac functions and morphology were detected by echocardiography and HE staining, respectively. In vitro, the effects of YQHX on H9c2 cell viability, LDH and ROS were detected, respectively. PGC-1α relevant proteins were evaluated by Western blotting.ResultsIn vivo, echocardiography and HE staining results showed that YQHX improved cardiac functions and modified pathological changes. YQHX enhanced PGC-1α expression and improved the mitochondrial ultrastructure and functions in rats MI model for 4 weeks. Further, we explored its potential mechanisms in cardiomyocytes. In vitro, YQHX significantly enhanced cell viability and reduced LDH release and ROS production induced by hypoxia in cardiomyocytes. Interestingly, exposure of cardiomyocytes to hypoxic conditions for 12 h induced the downregulation of PGC-1α expression, but the expression levels nearly returned to the normal state after hypoxia for 24 h. YQHX significantly enhanced PGC-1α expression between 12 h and 24 h induced by hypoxia through a mechanism associated with the activation of AMPK phosphorylation in H9c2 cells. In addition, YQHX upregulated the expression of Tfam and NRF-1, while NRF-1 expression was completely blocked by an AMPK inhibitor. YQHX largely restored the mitochondrial morphology and increased mitochondrial membrane potential in hypoxia-induced injury. Furthermore, the UHPLC-LTQ-Orbitrap-MSn analysis found that there were 87 chemical constituents in YQHX.ConclusionsThese results suggest that the protective effect of YQHX on cardiomyocytes against hypoxia-induced injury may be attributed to activation of PGC-1α and maintenance of mitochondrial functions through a mechanism involving the activation of AMPK phosphorylation.

Dataset Information

Dihydromyricetin Protects Against Gentamicin-Induced Ototoxicity via PGC-1?/SIRT3 Signaling in vitro.

Publications

Dihydromyricetin Protects Against Gentamicin-Induced Ototoxicity via PGC-1α/SIRT3 Signaling <i>in vitro</i>.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets