scholarly journals Alpha-synuclein-induced mitochondrial dysfunction is mediated via a sirtuin 3-dependent pathway

2018 ◽  
Author(s):  
Jae-Hyeon Park ◽  
Marion Delenclos ◽  
Ayman H. Faroqi ◽  
Natasha N. DeMeo ◽  
Pamela J. McLean
Keyword(s):  
Parkinson Disease ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Mitochondrial Dynamics ◽  
Lewy Body Disease ◽  
Camp Response Element Binding ◽  
Protective Role ◽  
Alpha Synuclein ◽  
Sirtuin 3

AbstractThe sirtuins are highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent enzymes that play a broad role in cellular metabolism and aging. Mitochondrial sirtuin 3 (SIRT3) is downregulated in aging and age-associated diseases such as cancer and neuro-degeneration and plays a major role in maintaining mitochondrial function and preventing oxidative stress. Mitochondria dysfunction is central to the pathogenesis of Parkinson disease with mutations in mitochondrial-associated proteins such as PINK1 and parkin causing familial Parkinson disease. Here, we demonstrate that the presence of alpha-synuclein (αsyn) oligomers in mitochondria induce a corresponding decrease in mitochondrial SIRT3 activity and decreased mitochondrial biogenesis. We show that SIRT3 downregulation in the presence of αsyn accumulation is accompanied by increased phosphorylation of AMP-activated protein kinase (AMPK) and cAMP-response element binding protein (CREB), as well as increased phosphorylation of dynamin-related protein 1 (DRP1) and decreased levels of optic atrophy 1 (OPA1), which is indicative of impaired mitochondrial dynamics. Treatment with the AMPK agonist 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR) restores SIRT3 expression and activity and improves mitochondrial function by decreasing αsyn oligomer formation. The accumulation of αsyn oligomers in mitochondria corresponds with SIRT3 down-regulation not only in an experimental cellular model, but also in vivo in a rodent model of Parkinson disease, and importantly, in human post mortem brains with neuropathologically confirmed Lewy body disease (LBD). Taken together our findings suggest that pharmacologically increasing SIRT3 levels will counteract αsyn-induced mitochondrial dysfunction by normalizing mitochondrial bioenergetics. These data support a protective role for SIRT3 in Parkinson disease-associated pathways and reveals significant mechanistic insight into the interplay of SIRT3 and αsyn.

scholarly journals ApoE4 (Δ272–299) induces mitochondrial‐associated membrane formation and mitochondrial impairment by enhancing GRP75-modulated mitochondrial calcium overload in neuron

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tao Liang ◽  
Weijian Hang ◽  
Jiehui Chen ◽  
Yue Wu ◽  
Bin Wen ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Er Stress ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Calcium Transport ◽  
Calcium Overload ◽  
Mitochondrial Calcium ◽  
Mitochondrial Impairment

Abstract Background Apolipoprotein E4 (apoE4) is a major genetic risk factor of Alzheimer’s disease. Its C-terminal-truncated apoE4 (Δ272–299) has neurotoxicity by affecting mitochondrial respiratory function. However, the molecular mechanism(s) underlying the action of apoE4 (Δ272–299) in mitochondrial function remain poorly understood. Methods The impact of neuronal apoE4 (Δ272–299) expression on ER stress, mitochondrial-associated membrane (MAM) formation, GRP75, calcium transport and mitochondrial impairment was determined in vivo and in vitro. Furthermore, the importance of ER stress or GRP75 activity in the apoE4 (Δ272–299)-promoted mitochondrial dysfunction in neuron was investigated. Results Neuronal apoE4 (Δ272–299) expression induced mitochondrial impairment by inducing ER stress and mitochondrial-associated membrane (MAM) formation in vivo and in vitro. Furthermore, apoE4 (Δ272–299) expression promoted GRP75 expression, mitochondrial dysfunction and calcium transport into the mitochondria in neuron, which were significantly mitigated by treatment with PBA (an inhibitor of ER stress), MKT077 (a specific GRP75 inhibitor) or GRP75 silencing. Conclusions ApoE4 (Δ272–299) significantly impaired neuron mitochondrial function by triggering ER stress, up-regulating GRP75 expression to increase MAM formation, and mitochondrial calcium overload. Our findings may provide new insights into the neurotoxicity of apoE4 (Δ272–299) against mitochondrial function and uncover new therapeutic targets for the intervention of Alzheimer’s disease.

scholarly journals Mfn2 Overexpression Attenuates MPTP Neurotoxicity In Vivo

2021 ◽  
Vol 22 (2) ◽  
pp. 601
Author(s):  
Fanpeng Zhao ◽  
Quillan Austria ◽  
Wenzhang Wang ◽  
Xiongwei Zhu
Keyword(s):  
Mitochondrial Dysfunction ◽  
Mitochondrial Dynamics ◽  
Significant Loss ◽  
Critical Event ◽  
Mitochondrial Fragmentation ◽  
Wild Type Littermate ◽  
Littermate Control ◽  
Mptp Administration

Mitochondrial dysfunction represents a critical event in the pathogenesis of Parkinson’s disease (PD). Increasing evidence demonstrates that disturbed mitochondrial dynamics and quality control play an important role in mitochondrial dysfunction in PD. Our previous study demonstrated that MPP+ induces mitochondrial fragmentation in vitro. In this study, we aimed to assess whether blocking MPTP-induced mitochondrial fragmentation by overexpressing Mfn2 affords neuroprotection in vivo. We found that the significant loss of dopaminergic neurons in the substantia nigra (SN) induced by MPTP treatment, as seen in wild-type littermate control mice, was almost completely blocked in mice overexpressing Mfn2 (hMfn2 mice). The dramatic reduction in dopamine neuronal fibers and dopamine levels in the striatum caused by MPTP administration was also partially inhibited in hMfn2 mice. MPTP-induced oxidative stress and inflammatory response in the SN and striatum were significantly alleviated in hMfn2 mice. The impairment of motor function caused by MPTP was also blocked in hMfn2 mice. Overall, our work demonstrates that restoration of mitochondrial dynamics by Mfn2 overexpression protects against neuronal toxicity in an MPTP-based PD mouse model, which supports the modulation of mitochondrial dynamics as a potential therapeutic target for PD treatment.

scholarly journals Neural stem cells traffic functional mitochondria via extracellular vesicles to correct mitochondrial dysfunction in target cells

2020 ◽  
Author(s):  
Luca Peruzzotti-Jametti ◽  
Joshua D. Bernstock ◽  
Giulia Manferrari ◽  
Rebecca Rogall ◽  
Erika Fernandez-Vizarra ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Stem Cell ◽  
Mitochondrial Dysfunction ◽  
Extracellular Vesicles ◽  
Mitochondrial Function ◽  
Mitochondrial Dynamics ◽  
Mononuclear Phagocytes ◽  
Host Cells ◽  
Target Cells ◽  
Therapeutic Effects

AbstractNeural stem cell (NSC) transplantation induces recovery in animal models of central nervous system (CNS) diseases. Although the replacement of lost endogenous cells was originally proposed as the primary healing mechanism of NSC grafts, it is now clear that transplanted NSCs operate via multiple mechanisms, including the horizontal exchange of therapeutic cargoes to host cells via extracellular vesicles (EVs).EVs are membrane particles trafficking nucleic acids, proteins, metabolites and metabolic enzymes, lipids and entire organelles. However, the function and the contribution of these cargoes to the broad therapeutic effects of NSCs is yet to be fully understood. Mitochondrial dysfunction is an established feature of several inflammatory and degenerative CNS disorders, most of which are potentially treatable with exogenous stem cell therapeutics.Herein we investigated the hypothesis that NSCs release and traffic functional mitochondria via EVs to restore mitochondrial function in target cells.Untargeted proteomics revealed a significant enrichment of mitochondrial proteins spontaneously released by NSCs in EVs. Morphological and functional analyses confirmed the presence of ultrastructurally intact mitochondria within EVs (Mito-EVs) with conserved membrane potential and respiration. We found that the transfer of Mito-EVs to mtDNA-deficient L929 Rho0 cells rescued mitochondrial function and increased Rho0 cell survival. Furthermore, the incorporation of Mito-EVs into inflammatory professional phagocytes restored normal mitochondrial dynamics and cellular metabolism and reduced the expression of pro-inflammatory markers in target cells. When transplanted in an animal model of multiple sclerosis, exogenous NSCs actively transferred mitochondria to mononuclear phagocytes and induced a significant amelioration of clinical deficits.Our data provide the first evidence that NSCs deliver functional mitochondria to target cells via Mito-EVs, paving the way for the development of novel (a)cellular approaches aimed at restoring mitochondrial dysfunction not only in multiple sclerosis, but also in degenerative neurological diseases.

Aplp1 and the Aplp1-Lag3 Complex facilitates transmission of pathologic alpha-synuclein

2021 ◽  
Author(s):  
Xiaobo Mao ◽  
Hao Gu ◽  
Donghoon Kim ◽  
Yasuyoshi Kimura ◽  
Ning Wang ◽  
...  
Keyword(s):  
Parkinson Disease ◽  
Molecular Mechanism ◽  
Amyloid Beta ◽  
Dopaminergic Neurons ◽  
Lymphocyte Activation ◽  
Alpha Synuclein ◽  
Therapeutic Strategies ◽  
Behavioral Deficits ◽  
Lymphocyte Activation Gene

Pathologic alpha-synuclein (alpha-syn) spreads from cell-to-cell, in part, through binding to the lymphocyte-activation gene 3 (Lag3). Here we report that amyloid beta precursor-like protein 1 (Aplp1) forms a complex with Lag3 that facilitates the binding, internalization, transmission, and toxicity of pathologic alpha-syn. Deletion of both Aplp1 and Lag3 eliminates the loss of dopaminergic neurons and the accompanying behavioral deficits induced by alpha-syn preformed fibrils (PFF). Anti-Lag3 prevents the internalization of alpha-syn PFF by disrupting the interaction of Aplp1 and Lag3, and blocks the neurodegeneration induced by alpha-syn PFF in vivo. The identification of Aplp1 and the interplay with Lag3 for alpha-syn PFF induced pathology advances our understanding of the molecular mechanism of cell-to-cell transmission of pathologic alpha-syn and provides additional targets for therapeutic strategies aimed at preventing neurodegeneration in Parkinson disease and related alpha-synucleinopathies.

scholarly journals Centella asiatica Attenuates Mitochondrial Dysfunction and Oxidative Stress in Aβ-Exposed Hippocampal Neurons

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Nora E. Gray ◽  
Jonathan A. Zweig ◽  
Donald G. Matthews ◽  
Maya Caruso ◽  
Joseph F. Quinn ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
Hippocampal Neurons ◽  
Neuroblastoma Cells ◽  
Water Extract ◽  
Centella Asiatica ◽  
Antioxidant Response ◽  
And Oxidative Stress

Centella asiatica has been used for centuries to enhance memory. We have previously shown that a water extract of Centella asiatica (CAW) protects against the deleterious effects of amyloid-β (Aβ) in neuroblastoma cells and attenuates Aβ-induced cognitive deficits in mice. Yet, the neuroprotective mechanism of CAW has yet to be thoroughly explored in neurons from these animals. This study investigates the effects of CAW on neuronal metabolism and oxidative stress in isolated Aβ-expressing neurons. Hippocampal neurons from amyloid precursor protein overexpressing Tg2576 mice and wild-type (WT) littermates were treated with CAW. In both genotypes, CAW increased the expression of antioxidant response genes which attenuated the Aβ-induced elevations in reactive oxygen species (ROS) and lipid peroxidation in Tg2576 neurons. CAW also improved mitochondrial function in both genotypes and increased the expression of electron transport chain enzymes and mitochondrial labeling, suggesting an increase in mitochondrial content. These data show that CAW protects against mitochondrial dysfunction and oxidative stress in Aβ-exposed hippocampal neurons which could contribute to the beneficial effects of the extract observed in vivo. Since CAW also improved mitochondrial function in the absence of Aβ, these results suggest a broader utility for other conditions where neuronal mitochondrial dysfunction occurs.

scholarly journals Alpha-synuclein-induced mitochondrial dysfunction is mediated via a sirtuin 3-dependent pathway

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Jae-Hyeon Park ◽  
Jeremy D. Burgess ◽  
Ayman H. Faroqi ◽  
Natasha N. DeMeo ◽  
Fabienne C. Fiesel ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
Alpha Synuclein ◽  
Sirtuin 3 ◽  
Dependent Pathway

scholarly journals Peripheral mitochondrial function correlates with clinical severity in idiopathic Parkinson’s disease

2018 ◽  
Author(s):  
Chiara Milanese ◽  
Cesar Payan-Gomez ◽  
Marta Galvani ◽  
Nicolás Molano González ◽  
Maria Tresini ◽  
...  
Keyword(s):  
Machine Learning ◽  
Parkinson Disease ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Energy Production ◽  
Alpha Synuclein ◽  
Clinical Severity ◽  
Bivariate Analysis ◽  
Mitochondrial Activity ◽  
Clinical Measures

AbstractBackgroundParkinson disease is an intractable disorder with heterogeneous clinical presentation that may reflect different underlying pathogenic mechanisms. Surrogate indicators of pathogenic processes correlating with clinical measures may assist in better patients stratification. Mitochondrial function - which is impaired in and central to PD pathogenesis - may represent one of such surrogate indicators.MethodsMitochondrial function was assessed by respirometry experiment in fibroblasts derived from idiopathic patients (n=47) in normal conditions and in experimental settings that do not permit glycolysis and therefore force energy production through mitochondrial function. Respiratory parameters and clinical measures were correlated with bivariate analysis. Machine learning based classification and regression trees were used to classify patients on the basis of biochemical and clinical measures. Effects of mitochondrial respiration on alpha-synuclein stress was assessed monitoring the protein phosphorylation in permitting versus restrictive glycolysis conditions.ResultsBioenergetics properties in peripheral fibroblasts correlate with clinical measures in idiopathic patients and correlation is stronger with predominantly non-dopaminergic signs. Bioenergetics analysis under metabolic stress, in which energy is produced solely by mitochondria, shows that patients’ fibroblasts can augment respiration, therefore indicating that mitochondrial defects are reversible. Forcing energy production through mitochondria, however, favors alpha-synuclein stress in different cellular experimental systems. Machine learning-based classification identified different groups of patients in which increasing disease severity parallels higher mitochondrial respiration.ConclusionSuppression of mitochondrial activity in Parkinson disease may be an adaptive strategy to cope with concomitant pathogenic factors. Moreover, mitochondrial measures are potential biomarkers to follow disease progression.

scholarly journals HDAC6: A Key Link Between Mitochondria and Development of Peripheral Neuropathy

2021 ◽  
Vol 14 ◽  
Author(s):  
Krystal English ◽  
Michelle Craig Barton
Keyword(s):  
Neuropathic Pain ◽  
Peripheral Neuropathy ◽  
Mitochondrial Dysfunction ◽  
Mitochondrial Dynamics ◽  
Health Concern ◽  
Major Player ◽  
Class Iib ◽  
Voltage Gated Ion Channels

Peripheral neuropathy, which is the result of nerve damage from lesions or disease, continues to be a major health concern due to the common manifestation of neuropathic pain. Most investigations into the development of peripheral neuropathy focus on key players such as voltage-gated ion channels or glutamate receptors. However, emerging evidence points to mitochondrial dysfunction as a major player in the development of peripheral neuropathy and resulting neuropathic pain. Mitochondrial dysfunction in neuropathy includes altered mitochondrial transport, mitochondrial metabolism, as well as mitochondrial dynamics. The mechanisms that lead to mitochondrial dysfunction in peripheral neuropathy are poorly understood, however, the Class IIb histone deacetylase (HDAC6), may play an important role in the process. HDAC6 is a key regulator in multiple mechanisms of mitochondrial dynamics and may contribute to mitochondrial dysregulation in peripheral neuropathy. Accumulating evidence shows that HDAC6 inhibition is strongly associated with alleviating peripheral neuropathy and neuropathic pain, as well as mitochondrial dysfunction, in in vivo and in vitro models of peripheral neuropathy. Thus, HDAC6 inhibitors are being investigated as potential therapies for multiple peripheral neuropathic disorders. Here, we review emerging studies and integrate recent advances in understanding the unique connection between peripheral neuropathy and mitochondrial dysfunction through HDAC6-mediated interactions.

scholarly journals Rooibos Flavonoids, Aspalathin, Isoorientin, and Orientin Ameliorate Antimycin A-Induced Mitochondrial Dysfunction by Improving Mitochondrial Bioenergetics in Cultured Skeletal Muscle Cells

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6289
Author(s):  
Sinenhlanhla X. H. Mthembu ◽  
Christo J. F. Muller ◽  
Phiwayinkosi V. Dludla ◽  
Evelyn Madoroba ◽  
Abidemi P. Kappo ◽  
...  
Keyword(s):  
Mitochondrial Dysfunction ◽  
Mitochondrial Function ◽  
C2c12 Myotubes ◽  
Antimycin A ◽  
Mrna Levels ◽  
Expression Of Genes ◽  
Rooibos Tea ◽  
The Impact ◽  
Dietary Flavonoids

The current study investigated the physiological effects of flavonoids found in daily consumed rooibos tea, aspalathin, isoorientin, and orientin on improving processes involved in mitochondrial function in C2C12 myotubes. To achieve this, C2C12 myotubes were exposed to a mitochondrial channel blocker, antimycin A (6.25 µM), for 12 h to induce mitochondrial dysfunction. Thereafter, cells were treated with aspalathin, isoorientin, and orientin (10 µM) for 4 h, while metformin (1 µM) and insulin (1 µM) were used as comparators. Relevant bioassays and real-time PCR were conducted to assess the impact of treatment compounds on some markers of mitochondrial function. Our results showed that antimycin A induced alterations in the mitochondrial respiration process and mRNA levels of genes involved in energy production. In fact, aspalathin, isoorientin, and orientin reversed such effects leading to the reduced production of intracellular reactive oxygen species. These flavonoids further enhanced the expression of genes involved in mitochondrial function, such as Ucp 2, Complex 1/3, Sirt 1, Nrf 1, and Tfam. Overall, the current study showed that dietary flavonoids, aspalathin, isoorientin, and orientin, have the potential to be as effective as established pharmacological drugs such as metformin and insulin in protecting against mitochondrial dysfunction in a preclinical setting; however, such information should be confirmed in well-established in vivo disease models.

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