scholarly journals The Protective Effect of Alpha-Mangostin against Cisplatin-Induced Cell Death in LLC-PK1 Cells is Associated to Mitochondrial Function Preservation

Antioxidants ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 133 ◽  
Author(s):  
Laura María Reyes-Fermín ◽  
Sabino Hazael Avila-Rojas ◽  
Omar Emiliano Aparicio-Trejo ◽  
Edilia Tapia ◽  
Isabel Rivero ◽  
...  
Keyword(s):  
Cell Death ◽  
Mitochondrial Function ◽  
Anion Channel ◽  
Laboratory Culture ◽  
Mitochondrial Morphology ◽  
Protective Effects ◽  
Mitofusin 2 ◽  
Mitochondrial Mass ◽  
Protein Levels ◽  
Function Preservation

Cis-dichlorodiammineplatinum II (CDDP) is a chemotherapeutic agent that induces nephrotoxicity by different mechanisms, including oxidative stress, mitochondrial dysfunction, autophagy, and endoplasmic reticulum stress. This study aimed to evaluate if the protective effects of the antioxidant alpha-mangostin (αM) in CDDP-induced damage in proximal tubule Lilly laboratory culture porcine kidney (LLC-PK1) cells, are related to mitochondrial function preservation. It was found that αM co-incubation prevented CDDP-induced cell death. Furthermore, αM prevented the CDDP-induced decrease in cell respiratory states, in the maximum capacity of the electron transfer system (E) and in the respiration associated to oxidative phosphorylation (OXPHOS). CDDP also decreased the protein levels of voltage dependence anion channel (VDAC) and mitochondrial complex subunits, which together with the reduction in E, the mitofusin 2 decrease and the mitochondrial network fragmentation observed by MitoTracker Green, suggest the mitochondrial morphology alteration and the decrease in mitochondrial mass induced by CDDP. CDDP also induced the reduction in mitochondrial biogenesis observed by transcription factor A, mitochondria (TFAM) decreased protein-level and the increase in mitophagy. All these changes were prevented by αM. Taken together, our results imply that αM’s protective effects in CDDP-induced toxicity in LLC-PK1 cells are associated to mitochondrial function preservation.

Abstract 24: Bnip3 Provokes ROS Production and Maladaptive Autophagy by Displacing Uncoupling Protein3 (UCP3) From Cytochrome c Oxidase of Respiration Chain Complex in Cardiotoxicity

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Rimpy Dhingra ◽  
Victoria Margulets ◽  
Davinder Jassal ◽  
Gerald Dorn II ◽  
Lorrie A. Kirshenbaum
Keyword(s):  
Cell Death ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Cardiac Myocytes ◽  
Mitochondrial Function ◽  
Uncoupling Protein ◽  
Mitochondrial Morphology ◽  
Necrotic Cell Death ◽  
Ros Production ◽  
Necrotic Cell

Doxorubicin is known for its cardiotoxic effects and inducing cardiac failure, however, the underlying mechanisms remain cryptic. Earlier we established the inducible - death protein, Bcl-2-like Nineteen- Kilodalton- Interacting - Protein 3 (Bnip3) to be crucial for disrupting mitochondrial function and inducing cell death of cardiac myocytes. Whether Bnip3 underlies cardiotoxic effects of doxorubicin toxicity is unknown. Herein we demonstrate a novel signaling pathway that functionally links activation and preferential mitochondrial targeting of Bnip3 to the cardiotoxic properties of doxorubicin. Perturbations to mitochondria including increased calcium loading, ROS, loss of αΨm and mPTP opening were observed in cardiac myocytes treated with doxorubicin. In mitochondria, Bnip3 forms strong association with Cytochrome c oxidase subunit1 (COX1) of respiratory chain and displaces uncoupling protein 3 (UCP3) resulting in increased ROS production, decline in maximal and reserved respiration capacity and cell viability. Impaired mitochondrial function was accompanied by an accumulated increase in autophagosomes and necrosis demonstrated by increase release of LDH, cTnT and loss of nuclear High Mobility Group Protein 1 (HMGB-1) immunoreactivity. Interestingly, pharmacological or genetic inhibition of autophagy with 3-methyl adenine (3-MA), or Atg7 knock-down suppressed necrotic cell death induced by doxorubicin. Loss of function of Bnip3 restored UCP3-COX complexes, mitochondrial respiratory integrity and abrogated necrotic cell death induced by doxorubicin. Mice germ-line deficient for Bnip3 were resistant to doxorubicin cardiotoxicity displaying normal mitochondrial morphology, cardiac function and survival rates comparable to vehicle treated mice. The findings of the present study demonstrate that doxorubicin provokes maladaptive autophagy and necrotic cell death of ventricular myocytes that is mutually dependent and obligatorily linked to Bnip3.

scholarly journals Bu-Yin-Qian-Zheng Formula Ameliorates MPP+-Induced Mitochondrial Dysfunction in Parkinson’s Disease via Parkin

2020 ◽  
Vol 11 ◽  
Author(s):  
Hao-Jie Ma ◽  
Cong Gai ◽  
Yuan Chai ◽  
Wan-Di Feng ◽  
Cui-Cui Cheng ◽  
...  
Keyword(s):  
Protein Expression ◽  
Mitochondrial Dysfunction ◽  
Cell Survival ◽  
Mitochondrial Function ◽  
Survival Rates ◽  
Transient Transfection ◽  
Mitochondrial Fusion ◽  
Mitochondrial Morphology ◽  
Protein Levels ◽  
Atp Levels

As a typical traditional Chinese medicine, Bu-Yin-Qian-Zheng Formula (BYQZF) has been shown to have neuroprotective effects in patients with Parkinson’s disease (PD), particularly by ameliorating mitochondrial dysfunction and regulating expression of the parkin protein. However, the underlying mechanisms by which BYQZF affects mitochondrial function through parkin are unclear. Accordingly, in this study, we evaluated the mechanisms by which BYQZF ameliorates mitochondrial dysfunction through parkin in PD. We constructed a parkin-knockdown cell model and performed fluorescence microscopy to observe transfected SH-SY5Y cells. Quantitative real-time reverse transcription polymerase chain reaction and western blotting were conducted to detect the mRNA and protein expression levels of parkin. Additionally, we evaluated the cell survival rates, ATP levels, mitochondrial membrane potential (ΔΨm), mitochondrial morphology, parkin protein expression, PINK1 protein expression, and mitochondrial fusion and fission protein expression after treatment with MPP+ and BYQZF. Our results showed that cell survival rates, ATP levels, ΔΨm, mitochondrial morphology, parkin protein levels, PINK1 protein levels, and mitochondrial fusion protein levels were reduced after MPP+ treatment. In contrast, mitochondrial fission protein levels were increased after MPP+ treatment. Moreover, after transient transfection with a negative control plasmid, the above indices were significantly increased by BYQZF. However, there were no obvious differences in these indices after transient transfection with a parkin-knockdown plasmid. Our findings suggest that BYQZF has protective effects on mitochondrial function in MPP+-induced SH-SY5Y cells via parkin-dependent regulation of mitochondrial dynamics.

Activation of Mitochondrial STAT3 Increases Mitochondrial Respiration and Inhibits Oxidative Stress in Chronic Lymphocytic Leukemic Cells

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 287-287 ◽  
Author(s):  
Li Jia ◽  
Nadiha Uddin ◽  
John G. Gribben
Keyword(s):  
Cell Death ◽  
Free Radical ◽  
Oxidative Damage ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Mitochondrial Mass ◽  
Free Radical Generation ◽  
Atp Turnover ◽  
Radical Generation

Abstract Abstract 287 Chronic lymphocytic leukemia (CLL) is a malignant disease occurring in the elderly and remains incurable. CLL is characterized by resistance to both spontaneous and induced apoptosis aided by changes induced by the tumor microenvironment. STAT3 is a signal responsive transcription factor that plays pivotal roles in tumorigensis in a number of malignancies including CLL. STAT3 resides in an inactive form in the cytoplasm of non-stimulated cells and in response to various cytokines and growth factors present in the microenvironment is activated through JAK-mediated phosphorylation of two residues, tyrosine 705 (Y705) and serine 727 (S727). Phosphorylation of this critical tyrosine residue (Y705) induces STAT3 dimerization through phosphotyrosine-SH2 domain interaction and. once dimerized, enters the nucleus and activates a broad array of target genes. The role of serine phosphorylation (S727) is less understood. It has been reported that STAT3 is constitutively phosphorylated on S727 and pS727-STAT3, not pY705-STAT3, binds DNA and activates transcription in CLL cells. However, it has also been reported that STAT3 is present in the mitochondria both in cell lines and primary liver and heart of mouse models, where it is one of the components of the mitochondrial electron transport chain (mETC) and plays an important role in mitochondrial respiration. The active form of mitochondrial STAT3 is pS727-STAT3 and it is crucial for Ras-dependent transformation by sustaining altered glycolytic and oxidative phosphorylation activities characteristic of cancer cells. It is unknown whether STAT3 regulates mitochondrial function in CLL. We therefore investigated whether activated STAT3 regulates mitochondrial respiration in CLL and whether it is important for CLL cell survival. Screening by Western blotting in untreated CLL patients' samples (n=16 )revealed that both pS727-STAT3 and pY705-STAT3 were constitutively expressed and we demonstrated correlation of the expression levels between these two active forms. Using fluorescent microscopy and cellular protein fractionation, both pS727-STAT3 and pY705-STAT3 showed mitochondrial localization in CLL cells. Stimulation of CLL cells with IL-10 induced STAT3 activation and both active forms of STAT3 exhibited mitochondrial translocation. The JAK inhibitor AG490 prevented STAT3 translocation to the mitochondria and led to reduction of mitochondrial mass and expression of cytochrome c oxidase IV (COX IV), one of the components of mETC. Knockdown of STAT3 RNA also decreased COX IV expression. Flow cytometry studies demonstrated that activation of STAT3 by IL-10 prevented depolarization of mitochondrial membrane potential and free radical generation by CLL cells, but inhibition of STAT3 induced mitochondrial oxidative damage and CLL cell death. The role of STAT3 activation by IL-10 on mitochondrial respiration was determined using a Seahorse XF Extracellular Flux Analyzer and demonstrated significantly increased coupled and uncoupled mitochondrial respiration and ATP turnover. Inhibition of STAT3 by AG490 reduced mitochondrial respiration and ATP turnover. However, decreased mitochondrial respiration did not provoke glycolytic capacity in CLL cells, indicating that CLL cells mainly rely on mitochondria for energetic needs. In summary, we demonstrate that activated STAT3 targets mitochondria and increases mitochondrial respiration and ATP turnover in CLL cells. This enables increased bioenergetic mitochondrial function and also prevents oxidative damage of CLL cells. Inhibition of STAT3 reduces mitochondrial mass and function but increases free radical generation and promotes CLL cell death. We therefore propose that mitochondrial STAT3 could be a therapeutic target for the treatment of CLL. Disclosures: Gribben: Roche: Honoraria; Celgene: Honoraria; GSK: Honoraria; Mundipharma: Honoraria; Gilead: Honoraria; Pharmacyclics: Honoraria.

scholarly journals Loading MiR-210 in Endothelial Progenitor Cells Derived Exosomes Boosts Their Beneficial Effects on Hypoxia/Reoxygeneation-Injured Human Endothelial Cells via Protecting Mitochondrial Function

2018 ◽  
Vol 46 (2) ◽  
pp. 664-675 ◽  
Author(s):  
Xiaotang Ma ◽  
Jinju Wang ◽  
Jiao Li ◽  
Chunlian Ma ◽  
Shuzhen Chen ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Mitochondrial Function ◽  
Tube Formation ◽  
Mechanism Analysis ◽  
Protective Effects ◽  
Endothelial Progenitor ◽  
Mitofusin 2 ◽  
Atp Level ◽  
Beneficial Effects ◽  
Angiogenesis Assay

Background/Aims: Stem cell-derived exosomes (EXs) offer protective effects on various cells via their carried microRNAs (miRs). Meanwhile, miR-210 has been shown to reduce mitochondrial reactive oxygen species (ROS) overproduction. In this study, we determined the potential effects of endothelial progenitor cell-derived EXs (EPC-EXs) on hypoxia/ reoxygenation (H/R) injured endothelial cells (ECs) and investigated whether these effects could be boosted by miR-210 loading. Methods: Human EPCs were used to generate EPC-EXs, or transfected with scrambler control or miR-210 mimics to generate EPC-EXssc and EPC-EXsmiR-210. H/R-injured human ECs were used as a model for functional analysis of EXs on apoptosis, viability, ROS production and angiogenic ability (migration and tube formation) by flow cytometry, MTT, dihydroethidium and angiogenesis assay kits, respectively. For mechanism analysis, the mitochondrion morphology, membrane potential (MMP), ATP level and the expression of fission/fusion proteins (dynamin-related protein 1: drp1 and mitofusin-2: mfn2) were assessed by using JC-1 staining, ELISA and western blot, respectively. Results: 1) Transfection of miR-210 mimics into EPCs induced increase of miR-210 in EPC-EXsmiR-210 without change of average size; 2) EPC-EXsmiR-210, but not EPC-EXs or EPC-EXssc, significantly elevated miR-210 level in ECs; 3) EPC-EXsmiR-210 were more effective than EPC-EXs and EPC-EXssc in reducing H/R-induced EC apoptosis, ROS overproduction and angiogenic dysfunction; 4) EPC-EXs decreased mitochondrial fragmentation, elevated MMP and ATP level, as well as improved mitochondrial mfn2 and drp1 dysregulation, which were more effective in EPC-EXsmiR-210. Conclusion: Our results suggest that EPC-EXs protect ECs against H/R injury via improving mitochondrial function and miR-210 enrichment could boost their effects.

scholarly journals Mitophagy enhancers against phosphorylated Tau-induced mitochondrial and synaptic toxicities in Alzheimer disease

2021 ◽  
Author(s):  
Sudhir Kshirsagar ◽  
Neha Sawant ◽  
Hallie Morton ◽  
Arubala Reddy ◽  
P. Hemachandra H Reddy
Keyword(s):  
Cell Survival ◽  
Mitochondrial Respiration ◽  
Individual Treatment ◽  
Mitochondrial Morphology ◽  
Protective Effects ◽  
Phosphorylated Tau ◽  
Ht22 Cells ◽  
Protein Levels ◽  
Combination Treatments ◽  
Urolithin A

The purpose of our study is to determine the protective effects of mitophagy enhancers against phosphorylated tau (P-tau)-induced mitochondrial and synaptic toxicities in Alzheimers disease (AD). Mitochondrial abnormalities, including defective mitochondrial dynamics, biogenesis, axonal transport and impaired clearance of dead mitochondria are linked to P-tau in AD. Mitophagy enhancers are potential therapeutic candidates to clear dead mitochondria and improve synaptic and cognitive functions in AD. We recently optimized the doses of mitophagy enhancers urolithin A, actinonin, tomatidine, nicotinamide riboside in immortalized mouse primary hippocampal (HT22) neurons. In the current study, we treated mutant Tau expressed in HT22 (mTau-HT22) cells with mitophagy enhancers and assessed mRNA and protein levels of mitochondrial/synaptic genes, cell survival and mitochondrial respiration. We also assessed mitochondrial morphology in mTau-HT22 cells treated and untreated with mitophagy enhancers. Mutant Tau-HT22 cells showed increased fission, decreased fusion, synaptic and mitophagy genes, reduced cell survival and defective mitochondrial respiration. However, these events were reversed in mitophagy enhancers treated mTau-HT22 cells. Cell survival was increased, mRNA and protein levels of mitochondrial fusion, synaptic and mitophagy genes were increased, and mitochondrial fragmentation is reduced in mitophagy enhancers treated mTau-HT22 cells. Further, urolithin A showed strongest protective effects among all enhancers tested in AD. Our combination treatments of urolithin A + EGCG, addition to urolithin A and EGCG individual treatment revealed that combination treatments approach is even stronger than urolithin A treatment. Based on these findings, we cautiously propose that mitophagy enhancers are promising therapeutic drugs to treat mitophagy in patients with AD.

Protective effects of mitophagy enhancers against amyloid beta-induced mitochondrial and synaptic toxicities in Alzheimer disease

2021 ◽  
Author(s):  
Sudhir Kshirsagar ◽  
Neha Sawant ◽  
Hallie Morton ◽  
Arubala P Reddy ◽  
P Hemachandra Reddy
Keyword(s):  
Cell Survival ◽  
Amyloid Beta ◽  
Mitochondrial Respiration ◽  
Mitochondrial Dynamics ◽  
Disease Process ◽  
Mitochondrial Morphology ◽  
Protective Effects ◽  
Ht22 Cells ◽  
Protein Levels ◽  
Urolithin A

Abstract The purpose of our study is to determine the protective effects of mitophagy enhancers against mutant APP and amyloid beta (Aβ)-induced mitochondrial and synaptic toxicities in Alzheimer’s disease (ad). Over two decades of research from our lab and others revealed that mitochondrial abnormalities are largely involved in the pathogenesis of both early-onset and late-onset ad. Emerging studies from our lab and others revealed that impaired clearance of dead or dying mitochondria is an early event in the disease process. Based on these changes, it has been proposed that mitophagy enhancers are potential therapeutic candidates to treat patients with ad. In the current study, we optimized doses of mitophagy enhancers urolithin A, actinonin, tomatidine, nicotinamide riboside in immortalized mouse primary hippocampal (HT22) neurons. We transfected HT22 cells with mutant APP cDNA and treated with mitophagy enhancers and assessed mRNA and protein levels of mitochondrial dynamics, biogenesis, mitophagy and synaptic genes, cell survival; assessed mitochondrial respiration in mAPP-HT22 cells treated and untreated with mitophagy enhancers. We also assessed mitochondrial morphology in mAPP-HT22 cells treated and untreated with mitophagy enhancers. Mutant APP-HT22 cells showed increased fission, decreased fusion, synaptic & mitophagy genes, reduced cell survival and defective mitochondrial respiration, and excessively fragmented and reduced length of mitochondria. However, these events were reversed in mitophagy enhancers treated mutant mAPP-HT22 cells. Cell survival was significantly increased, mRNA and protein levels of mitochondrial fusion, synaptic and mitophagy genes were increased, mitochondrial number is reduced, & mitochondrial length is increased, and mitochondrial fragmentation is reduced in mitophagy enhancers treated mutant APP-HT22 cells. Further, urolithin A showed strongest protective effects against mutant APP and Aβ-induced mitochondrial and synaptic toxicities in ad. Based on these findings, we cautiously propose that mitophagy enhancers are promising therapeutic drugs to treat mitophagy in patients with ad.

scholarly journals Hispidulin Attenuates Cardiac Hypertrophy by Improving Mitochondrial Dysfunction

2020 ◽  
Vol 7 ◽  
Author(s):  
Yan Wang ◽  
Zengshuo Xie ◽  
Nan Jiang ◽  
Zexuan Wu ◽  
Ruicong Xue ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Cardiac Hypertrophy ◽  
Mitochondrial Function ◽  
Specific Inhibitor ◽  
Cardiomyocyte Hypertrophy ◽  
Mitochondrial Morphology ◽  
Protective Effects

Cardiac hypertrophy is a pathophysiological response to harmful stimuli. The continued presence of cardiac hypertrophy will ultimately develop into heart failure. The mitochondrion is the primary organelle of energy production, and its dysfunction plays a crucial role in the progressive development of heart failure from cardiac hypertrophy. Hispidulin, a natural flavonoid, has been substantiated to improve energy metabolism and inhibit oxidative stress. However, how hispidulin regulates cardiac hypertrophy and its underlying mechanism remains unknown. We found that hispidulin significantly inhibited pressure overload-induced cardiac hypertrophy and improved cardiac function in vivo and blocked phenylephrine (PE)-induced cardiomyocyte hypertrophy in vitro. We further proved that hispidulin remarkably improved mitochondrial function, manifested by increased electron transport chain (ETC) subunits expression, elevated ATP production, increased oxygen consumption rates (OCR), normalized mitochondrial morphology, and reduced oxidative stress. Furthermore, we discovered that Sirt1, a well-recognized regulator of mitochondrial function, might be a target of hispidulin, as evidenced by its upregulation after hispidulin treatment. Cotreatment with EX527 (a Sirt1-specific inhibitor) and hispidulin nearly completely abolished the antihypertrophic and protective effects of hispidulin on mitochondrial function, providing further evidence that Sirt1 could be the pivotal downstream effector of hispidulin in regulating cardiac hypertrophy.

scholarly journals Luteolin Prevents Cardiac Dysfunction and Improves the Chemotherapeutic Efficacy of Doxorubicin in Breast Cancer

2021 ◽  
Vol 8 ◽  
Author(s):  
Youyang Shi ◽  
Feifei Li ◽  
Man Shen ◽  
Chenpin Sun ◽  
Wei Hao ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mitochondrial Fission ◽  
Mitochondrial Morphology ◽  
Protective Effects ◽  
Myocardial Cells ◽  
Related Protein ◽  
Zebrafish Model ◽  
Protein Levels

Background: Doxorubicin (Dox) is one of the most effective chemotherapy agents used in the treatment of solid tumors and hematological malignancies. However, it causes dose-related cardiotoxicity that may lead to heart failure in patients. Luteolin (Lut) is a common flavonoid that exists in many types of plants. It has been studied for treating various diseases such as hypertension, inflammatory disorders, and cancer. In this study, we evaluated the cardioprotective and anticancer effects of Lut on Dox-induced cardiomyopathy in vitro and in vivo to explore related mechanisms in alleviating dynamin-related protein (Drp1)-mediated mitochondrial apoptosis.Methods: MTT and LDH assay were used to determine the viability and toxicity of cardiomyocytes treated with Dox and Lut. Flow cytometry was used to examine ROS levels, and electron and confocal microscopy was employed to assess the mitochondrial morphology. The level of apoptosis was examined by Hoechst 33258 staining. The protein levels of myocardial fission protein and apoptosis-related protein were examined using Western blot. Transcriptome analysis of the protective effect of Lut against Dox-induced cardiac toxicity in myocardial cells was performed using RNA sequencing technology. The protective effects of Lut against cardiotoxicity mediated by Dox in zebrafish were quantified. The effect of Lut increase the antitumor activity of Dox in breast cancer both in vitro and in vivo were further employed.Results: Lut ameliorated Dox-induced toxicity in H9c2 and AC16 cells. The level of oxidative stress was downregulated by Lut after Dox treatment of myocardial cells. Lut effectively reduced the increased mitochondrial fission post Dox stimulation in cardiomyocytes. Apoptosis, fission protein Drp1, and Ser616 phosphorylation were also increased post Dox and reduced by Lut. In the zebrafish model, Lut significantly preserved the ventricular function of zebrafish after Dox treatment. Moreover, in the mouse model, Lut prevented Dox-induced cardiotoxicity and enhanced the cytotoxicity in triple-negative breast cancer by inhibiting proliferation and metastasis and inducing apoptosis.

Abstract 78: TNFR2 Stimulation Promotes Mitochondrial Fusion via Stat3 and NF-kB Dependent Activation of OPA1 Expression

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Jing-Liang Nan ◽  
Wei Zhu ◽  
Ying-Chao Wang ◽  
Zhi-Wei Zhong ◽  
Lian-lian Zhu ◽  
...  
Keyword(s):  
Mitochondrial Fusion ◽  
Mitochondrial Morphology ◽  
Protective Effects ◽  
Promoter Regions ◽  
Neonatal Cardiomyocytes ◽  
Protein Levels ◽  
Dynamic Simulation Model ◽  
Underlying Mechanisms ◽  
Reported Data ◽  
And Function

Background: TNFR2 stimulation is known to possess protective effects for the cardiomyocytes, however, the underlying mechanisms remain unknown. Methods and Results: Using cultured neonatal cardiomyocytes that were infected with lentivirus containing shRNA targeting TNFR1, we showed that TNFR2 activation by TNFα (5nmol/L) resulted in increased mitochondrial fusion, mitochondrial membrane potential which were associated with both elevated intracellular ATP levels and oxygen consumption rate. Intriguingly, these changes were associated with increased protein levels of OPA1, with no changes in the expression levels of Drp1, Mfn1, Mfn2. We went further and reproduced previously reported data that NF-kB acetylation (Lys310) was increased with TNFR2 activation. Interestingly, however, we also observed dose-dependent effects on increase in Stat3 acetylation. Using shRNA approach, we then demonstrated that either Stat3 or NF-kB knockdown can attenuate TNFR2 induced OPA1 expression. The close interaction between these two signalings was validated by co-IP assay and confocal immunofluorescence staining. Aided by bio-informatics searching, we then performed ChIP assay to show that the binding sites of OPA1 promoter regions for STAT3 (-156 to -167) and NFkB (-192 to -203) were adjacent. We further validated that p300 induced Stat3 acetylation was indispensable for complex formation by the interaction between Stat3-DBD and NF-kB -ΔRHD, which in turn was a key event for OPA1 transcription activation. And silence of p300 can abolish OPA1 upregulation upon TNFR2 activation. Computerized data analysis based on zdock and zrank score followed by molecular dynamic simulation model for the whole Stat3 structure revealed higher value of the exterior dielectric constant (obtained from MM/PBSA calculation) for the two sites, K370 and K383, of Stat3, suggesting the essential roles for these two sites for Stat3-NFkB interaction, which were confirmed by co-IP with Stat3-DBD mutants (K370Q,K370R,K383Q,K383R) approach. Conclusions: Our data suggested that p300 mediated Stat3 acetylation cooperates with NF-kB to modulate TNFR2 activation induced OPA1 upregulation, leading to improved mitochondrial morphology and function.

scholarly journals Protective Effects of Dexmedetomidine on the Vascular Endothelial Barrier Function by Inhibiting Mitochondrial Fission via ER/Mitochondria Contact

2021 ◽  
Vol 9 ◽  
Author(s):  
Han She ◽  
Yu Zhu ◽  
Haoyue Deng ◽  
Lei Kuang ◽  
He Fang ◽  
...  
Keyword(s):  
Mitochondrial Function ◽  
Barrier Function ◽  
Mitochondrial Fission ◽  
Endothelial Barrier ◽  
Mitochondrial Morphology ◽  
Vascular Endothelial ◽  
Protective Effects ◽  
Endothelial Barrier Function ◽  
Mitochondrial Division ◽  
Contact Sites

The damage of vascular endothelial barrier function induced by sepsis is critical in causing multiple organ dysfunctions. Previous studies showed that dexmedetomidine (Dex) played a vital role in protecting organ functions. However, whether Dex participates in protecting vascular leakage of sepsis and the associated underlying mechanism remains unknown yet. We used cecal ligation and puncture induced septic rats and lipopolysaccharide stimulated vascular endothelial cells (VECs) to establish models in vivo and in vitro, then the protective effects of Dex on the vascular endothelial barrier function of sepsis were observed, meanwhile, related mechanisms on regulating mitochondrial fission were further studied. The results showed that Dex could significantly reduce the permeability of pulmonary veins and mesenteric vessels, increase the expression of intercellular junction proteins, enhance the transendothelial electrical resistance and decrease the transmittance of VECs, accordingly protected organ functions and prolonged survival time in septic rats. Besides, the mitochondria of VECs were excessive division after sepsis, while Dex could significantly inhibit the mitochondrial fission and protect mitochondrial function by restoring mitochondrial morphology of VECs. Furthermore, the results showed that ER-MITO contact sites of VECs were notably increased after sepsis. Nevertheless, Dex reduced ER-MITO contact sites by regulating the polymerization of actin via α2 receptors. The results also found that Dex could induce the phosphorylation of the dynamin-related protein 1 through down-regulating extracellular signal-regulated kinase1/2, thus playing a role in the regulation of mitochondrial division. In conclusion, Dex has a protective effect on the vascular endothelial barrier function of septic rats. The mechanism is mainly related to the regulation of Drp1 phosphorylation of VECs, inhibition of mitochondrial division by ER-MITO contacts, and protection of mitochondrial function.

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