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 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.

scholarly journals Hydromorphone Protects against CO2 Pneumoperitoneum-Induced Lung Injury via Heme Oxygenase-1-Regulated Mitochondrial Dynamics

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Jia Shi ◽  
Shi-Han Du ◽  
Jian-Bo Yu ◽  
Yan-Fang Zhang ◽  
Si-Meng He ◽  
...  
Keyword(s):  
Lung Injury ◽  
Heme Oxygenase ◽  
Mitochondrial Dynamics ◽  
Stress Index ◽  
Heme Oxygenase 1 ◽  
Mitochondrial Morphology ◽  
Gynecological Surgery ◽  
Protective Effects ◽  
Co2 Pneumoperitoneum ◽  
Blood Samples

Various pharmacological agents and protective methods have been shown to reverse pneumoperitoneum-related lung injury, but identifying the best strategy is challenging. Herein, we employed lung tissues and blood samples from C57BL/6 mice with pneumoperitoneum-induced lung injury and blood samples from patients who received laparoscopic gynecological surgery to investigate the therapeutic role of hydromorphone in pneumoperitoneum-induced lung injury along with the underlying mechanism. We found that pretreatment with hydromorphone alleviated lung injury in mice that underwent CO2 insufflation, decreased the levels of myeloperoxidase (MPO), total oxidant status (TOS), and oxidative stress index (OSI), and increased total antioxidant status (TAS). In addition, after pretreatment with hydromorphone, upregulated HO-1 protein expression, reduced mitochondrial DNA content, and improved mitochondrial morphology and dynamics were observed in mice subjected to pneumoperitoneum. Immunohistochemical staining also verified that hydromorphone could increase the expression of HO-1 in lung tissues in mice subjected to CO2 pneumoperitoneum. Notably, in mice treated with HO-1-siRNA, the protective effects of hydromorphone against pneumoperitoneum-induced lung injury were abolished, and hydromorphone did not have additional protective effects on mitochondria. Additionally, in clinical patients who received laparoscopic gynecological surgery, pretreatment with hydromorphone resulted in lower serum levels of club cell secretory protein-16 (CC-16) and intercellular adhesion molecule-1 (ICAM-1), a lower prooxidant-antioxidant balance (PAB), and higher heme oxygenase-1 (HO-1) activity than morphine pretreatment. Collectively, our results suggest that hydromorphone protects against CO2 pneumoperitoneum-induced lung injury via HO-1-regulated mitochondrial dynamics and may be a promising strategy to treat CO2 pneumoperitoneum-induced lung injury.

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.

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.

scholarly journals Aralia taibaiensis Protects against I/R-Induced Brain Cell Injury through the Akt/SIRT1/FOXO3a Pathway

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Jialin Duan ◽  
Jia Cui ◽  
Hongnan Zheng ◽  
Miaomiao Xi ◽  
Chao Guo ◽  
...  
Keyword(s):  
Cell Injury ◽  
Ischemia Reperfusion ◽  
Brain Cells ◽  
Intragastric Administration ◽  
Dependent Manner ◽  
Protective Effects ◽  
Ht22 Cells ◽  
Protein Levels

Background. Saponin from Aralia taibaiensis (sAT) showed excellent antioxidative effects in several models; however, its effects on brain cells were unknown to us. The present study was designed to evaluate the protective effects of sAT on ischemia/reperfusion- (I/R-) induced injury and clarify its mechanisms. Methods. In vitro, HT22 cells were pretreated with sAT and then subjected to I/R. Apoptosis rate, mitochondrial function, and antioxidant proteins were measured. To clarify the mechanisms, siRNA were used. In vivo, sAT was pretreated through intragastric administration for 7 days and the I/R model was induced. The neurobehavioral scores, infarction volumes, and some cytokines in the brain were measured. Protein levels were investigated by Western blotting. Results. The results showed that sAT treatment significantly protected cells from I/R-induced cell apoptosis and mitochondrial dysfunction. The antioxidant protein levels were increased in a dose-dependent manner. Further study revealed that sAT induced the deacetylation and phosphorylation of PGC-1α and FOXO3a. sAT treatment also induced the phosphorylation levels of Akt and the expression levels of SIRT1. Using the specific targeted siRNA transfection, the interplay relationship between Akt, SIRT1, PGC-1α, and FOXO3a was verified. Furthermore, the same protective effects were also observed in rats subjected to I/R. Conclusion. sAT protected brain cells from I/R-induced mitochondrial oxidative stress and dysfunction through regulating the Akt/SIRT1/FOXO3a/PGC-1α pathway.

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.

scholarly journals Squamosamide Derivative FLZ Diminishes Aberrant Mitochondrial Fission by Inhibiting Dynamin-Related Protein 1

2021 ◽  
Vol 12 ◽  
Author(s):  
Hanyu Yang ◽  
Lu Wang ◽  
Caixia Zang ◽  
Xu Yang ◽  
Xiuqi Bao ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
Dopaminergic Neurons ◽  
Motor Coordination ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Mitochondrial Morphology ◽  
Protective Effects ◽  
Related Protein ◽  
Mitochondrial Fragmentation

Mitochondrial dysfunction is involved in the pathogenesis of Parkinson’s disease (PD). Mitochondrial morphology is dynamic and precisely regulated by mitochondrial fission and fusion machinery. Aberrant mitochondrial fragmentation, which can result in cell death, is controlled by the mitochondrial fission protein, dynamin-related protein 1 (Drp1). Our previous results demonstrated that FLZ could correct mitochondrial dysfunction, but the effect of FLZ on mitochondrial dynamics remain uncharacterized. In this study, we investigated the effect of FLZ and the role of Drp1 on 1-methyl-4-phenylpyridinium (MPP+)–induced mitochondrial fission in neurons. We observed that FLZ blocked Drp1, inhibited Drp1 enzyme activity, and reduced excessive mitochondrial fission in cultured neurons. Furthermore, by inhibiting mitochondrial fission and ROS production, FLZ improved mitochondrial integrity and membrane potential, resulting in neuroprotection. FLZ curtailed the reduction of synaptic branches of primary cultured dopaminergic neurons caused by MPP+ exposure, reduced abnormal fission, restored normal mitochondrial distribution in neurons, and exhibited protective effects on dopaminergic neurons. The in vitro research results were validated using an MPTP-induced PD mouse model. The in vivo results revealed that FLZ significantly reduced the mitochondrial translocation of Drp1 in the midbrain of PD mice, which, in turn, reduced the mitochondrial fragmentation in mouse substantia nigra neurons. FLZ also protected dopaminergic neurons in PD mice and increased the dopamine content in the striatum, which improved the motor coordination ability of the mice. These findings elucidate this newly discovered mechanism through which FLZ produces neuroprotection in PD.

scholarly journals Blocked O-GlcNAc cycling alters mitochondrial morphology, function, and mass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Elizabeth O. Akinbiyi ◽  
Lara K. Abramowitz ◽  
Brianna L. Bauer ◽  
Maria S. K. Stoll ◽  
Charles L. Hoppel ◽  
...  
Keyword(s):  
Cellular Localization ◽  
Mitochondrial Dynamics ◽  
Mitochondrial Fission ◽  
Mitochondrial Morphology ◽  
Post Translational Modification ◽  
Mitochondrial Content ◽  
Protein Levels ◽  
Cellular Environment ◽  
And Function ◽  
The Impact

AbstractO-GlcNAcylation is a prevalent form of glycosylation that regulates proteins within the cytosol, nucleus, and mitochondria. The O-GlcNAc modification can affect protein cellular localization, function, and signaling interactions. The specific impact of O-GlcNAcylation on mitochondrial morphology and function has been elusive. In this manuscript, the role of O-GlcNAcylation on mitochondrial fission, oxidative phosphorylation (Oxphos), and the activity of electron transport chain (ETC) complexes were evaluated. In a cellular environment with hyper O-GlcNAcylation due to the deletion of O-GlcNAcase (OGA), mitochondria showed a dramatic reduction in size and a corresponding increase in number and total mitochondrial mass. Because of the increased mitochondrial content, OGA knockout cells exhibited comparable coupled mitochondrial Oxphos and ATP levels when compared to WT cells. However, we observed reduced protein levels for complex I and II when comparing normalized mitochondrial content and reduced linked activity for complexes I and III when examining individual ETC complex activities. In assessing mitochondrial fission, we observed increased amounts of O-GlcNAcylated dynamin-related protein 1 (Drp1) in cells genetically null for OGA and in glioblastoma cells. Individual regions of Drp1 were evaluated for O-GlcNAc modifications, and we found that this post-translational modification (PTM) was not limited to the previously characterized residues in the variable domain (VD). Additional modification sites are predicted in the GTPase domain, which may influence enzyme activity. Collectively, these results highlight the impact of O-GlcNAcylation on mitochondrial dynamics and ETC function and mimic the changes that may occur during glucose toxicity from hyperglycemia.

scholarly journals Titanium Dioxide Nanoparticles Induce Mitochondrial Dynamic Imbalance and Damage in HT22 Cells

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Han Zhao ◽  
Liang Chen ◽  
Guisheng Zhong ◽  
Yina Huang ◽  
Xulai Zhang ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
B Cell ◽  
Cell Lymphoma ◽  
Mitochondrial Dynamics ◽  
Titanium Dioxide Nanoparticles ◽  
B Cell Lymphoma ◽  
Stimulated Emission ◽  
Mitochondrial Morphology ◽  
Mitochondrial Dynamic ◽  
Ht22 Cells

Mitochondria, as dynamic organelles, are precisely regulated by fusion and fission. The dynamic balance of fusion and fission controls mitochondrial morphology and their subcellular location and function. Exposure to titanium dioxide nanoparticles (TiO2 NPs) may cause serious health problems. However, how TiO2 NPs affect the mitochondrial dynamics remains unclear. In the present study, we investigated the changes of mitochondrial dynamics in the TiO2NPs-treated HT22 cells by confocal and stimulated emission depletion (STED) microscopy. The confocal images demonstrated obvious changes in the average length and density of the mitochondria after TiO2 NPs treatment, while STED images further obtained the nanoscale submitochondrial structures of the mitochondria under TiO2 NPs insult. The fluorescence intensity distributions suggested that mitochondria fragmented in the TiO2 NPs-treated cells. TiO2 NPs treatment caused mitochondrial dynamic imbalance due to the imbalanced expression of dynamin-related protein 1 (Drp1) and optic atrophy 1 (Opa1). Furthermore, we examined the levels of oxidative stress and mitochondrial membrane potential (MMP) and the generation of adenosine triphosphate (ATP), which revealed the damage of mitochondria under TiO2 NPs exposure. Meanwhile, the significant changes of expressions of B-cell lymphoma 2-associated X protein (Bax), B-cell lymphoma 2 (Bcl-2), cytochrome c (Cyt C), and caspase 9 demonstrated that TiO2 NPs treatment activated the mitochondrial-related apoptosis pathway. These cellular events can be largely prevented via cell incubation with mitoTEMPO, a mitochondria-targeted superoxide scavenger. Our results confirm that TiO2 NPs targeted the mitochondria, inducing mitochondrial dynamic imbalance and damage in HT22 cells. Our study provides an insightful understanding of the mechanisms underlying TiO2 NPs cytotoxicity.

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