Diversity in the Regulation of Autophagy and Mitophagy: Lessons from Parkinson's Disease

Selective mitochondrial degradation through autophagy (mitophagy) has emerged as an important homeostatic mechanism in a variety of organisms and contexts. Complete clearance of mitochondria can be observed during normal maturation of certain mammalian cell types, and during certain forms of neuronal cell death. In recent years, autophagy dysregulation has been implicated in toxin-injured dopaminergic neurons as well as in major genetic models of Parkinson's disease (PD), includingα-synuclein, leucine-rich repeat kinase 2 (LRRK2), parkin, PTEN-induced kinase 1 (PINK1), and DJ-1. Indeed, PINK1-parkin interactions may form the basis of a mechanism by which dissipation of the inner mitochondrial membrane potential can trigger selective mitochondrial targeting for autophagy. Multiple signals are likely to exist, however, depending upon the trigger for mitophagy. Similarly, the regulation of basal or injury-induced autophagy does not always follow canonical pathways described for nutrient deprivation. Implications of this regulatory diversity are discussed in the context of neuronal function and survival. Further studies are needed to address whether alterations in autophagy regulation play a directly injurious role in PD pathogenesis, or if the observed changes reflect impaired, appropriate, or excessive autophagic responses to other forms of cellular injury.

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Alpha synuclein aggresomes inhibit ciliogenesis and multiple functions of the centrosome

10.1101/2019.12.20.884643 ◽

2019 ◽

Author(s):

Anila Iqbal ◽

Marta Baldrighi ◽

Jennifer N. Murdoch ◽

Angeleen Fleming ◽

Christopher J. Wilkinson

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Dopaminergic Neurons ◽

Intracellular Transport ◽

Neuronal Cell Death ◽

Lewy Bodies ◽

Neuronal Cell ◽

Cell Types ◽

Alpha Synuclein ◽

Microtubule Network

AbstractProtein aggregates are the pathogenic hallmarks of many different neurodegenerative diseases and include the Lewy bodies found in Parkinson’s disease. Aggresomes are closely-related cellular accumulations of misfolded proteins. They develop in a juxtanuclear position, adjacent to the centrosome, the microtubule organizing centre of the cell, and share some protein components. Despite the long-standing observation that aggresomes/Lewy bodies and the centrosome sit side-by-side in the cell, no studies have been done to see whether these protein accumulations impede the organelle function. We investigated whether the formation of aggresomes affected key centrosome functions: its ability to organize the microtubule network and to promote cilia formation. We find that when aggresomes are present, neuronal cells are unable to organise their microtubule network. New microtubules are not nucleated and extended, and the cells fail to respond to polarity cues. Since dopaminergic neurons are polarised, ensuring correct localisation of organelles and the effective intracellular transport of neurotransmitter vesicles, loss of centrosome activity could contribute to loss of dopaminergic function and neuronal cell death in Parkinson’s disease. In addition, we provide evidence that many cell types, including dopaminergic neurons, cannot form cilia when aggresomes are present, which would affect their ability to receive extracellular signals.

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Alpha-synuclein aggresomes inhibit ciliogenesis and multiple functions of the centrosome

Biology Open ◽

10.1242/bio.054338 ◽

2020 ◽

Vol 9 (10) ◽

pp. bio054338

Author(s):

Anila Iqbal ◽

Marta Baldrighi ◽

Jennifer N. Murdoch ◽

Angeleen Fleming ◽

Christopher J. Wilkinson

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Intracellular Transport ◽

Neuronal Cell Death ◽

Lewy Bodies ◽

Neuronal Cell ◽

Cell Types ◽

Alpha Synuclein ◽

Microtubule Network ◽

Main Component

ABSTRACTProtein aggregates are the pathogenic hallmarks of many different neurodegenerative diseases and include the accumulation of α-synuclein, the main component of Lewy bodies found in Parkinson's disease. Aggresomes are closely-related, cellular accumulations of misfolded proteins. They develop in a juxtanuclear position, adjacent to the centrosome, the microtubule organizing centre of the cell, and share some protein components. Despite the long-standing observation that aggresomes/Lewy bodies and the centrosome sit side-by-side in the cell, no studies have been done to see whether these protein accumulations impede organelle function. We investigated whether the formation of aggresomes affected key centrosome functions: its ability to organise the microtubule network and to promote cilia formation. We find that when aggresomes are present, neuronal cells are unable to organise their microtubule network. New microtubules are not nucleated and extended, and the cells fail to respond to polarity cues. Since neurons are polarised, ensuring correct localisation of organelles and the effective intracellular transport of neurotransmitter vesicles, loss of centrosome activity could contribute to functional deficits and neuronal cell death in Parkinson's disease. In addition, we provide evidence that many cell types, including dopaminergic neurons, cannot form cilia when aggresomes are present, which would affect their ability to receive extracellular signals.

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PEP-1-GLRX1 Reduces Dopaminergic Neuronal Cell Loss by Modulating MAPK and Apoptosis Signaling in Parkinson’s Disease

Molecules ◽

10.3390/molecules26113329 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3329

Author(s):

Yeon Joo Choi ◽

Dae Won Kim ◽

Min Jea Shin ◽

Hyeon Ji Yeo ◽

Eun Ji Yeo ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cell Death ◽

Dopaminergic Neurons ◽

Therapeutic Agent ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Cell Loss ◽

Dopaminergic Neuronal Cell ◽

Apoptosis Related Protein

Parkinson’s disease (PD) is characterized mainly by the loss of dopaminergic neurons in the substantia nigra (SN) mediated via oxidative stress. Although glutaredoxin-1 (GLRX1) is known as one of the antioxidants involved in cell survival, the effects of GLRX1 on PD are still unclear. In this study, we investigated whether cell-permeable PEP-1-GLRX1 inhibits dopaminergic neuronal cell death induced by 1-methyl-4-phenylpyridinium (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We showed that PEP-1-GLRX1 protects cell death and DNA damage in MPP+-exposed SH-SY5Y cells via the inhibition of MAPK, Akt, and NF-κB activation and the regulation of apoptosis-related protein expression. Furthermore, we found that PEP-1-GLRX1 was delivered to the SN via the blood–brain barrier (BBB) and reduced the loss of dopaminergic neurons in the MPTP-induced PD model. These results indicate that PEP-1-GLRX1 markedly inhibited the loss of dopaminergic neurons in MPP+- and MPTP-induced cytotoxicity, suggesting that this fusion protein may represent a novel therapeutic agent against PD.

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Subcellular proteomics of dopamine neurons in the mouse brain reveals axonal enrichment of proteins encoded by Parkinson's disease-linked genes

10.1101/2021.06.01.446584 ◽

2021 ◽

Author(s):

Benjamin D. Hobson ◽

Se Joon Choi ◽

Rajesh K. Soni ◽

David Sulzer ◽

Peter A Sims

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Mouse Brain ◽

Dopaminergic Neurons ◽

Cell Biology ◽

Neuronal Cell ◽

Cell Types ◽

Dopamine Neurons ◽

Cell Type Specificity ◽

Subcellular Proteomics

Dopaminergic neurons modulate neural circuits and behaviors via dopamine release from expansive, long range axonal projections. The elaborate cytoarchitecture of these neurons is embedded within complex brain tissue, making it difficult to access the neuronal proteome using conventional methods. Here, we demonstrate APEX2 proximity labeling within genetically targeted neurons in the mouse brain, enabling subcellular proteomics with cell type-specificity. By combining APEX2 biotinylation with mass spectrometry, we mapped the somatodendritic and axonal proteomes of midbrain dopaminergic neurons. Our dataset reveals the proteomic architecture underlying proteostasis, axonal metabolism, and neurotransmission in these neurons. We find a significant enrichment of proteins encoded by Parkinson's disease-linked genes in striatal dopaminergic axons, including proteins with previously undescribed axonal localization. These proteomic datasets provide a resource for neuronal cell biology, and this approach can be readily adapted for study of other neural cell types.

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Cytokinin Plant Hormones Have Neuroprotective Activity in In Vitro Models of Parkinson’s Disease

Molecules ◽

10.3390/molecules26020361 ◽

2021 ◽

Vol 26 (2) ◽

pp. 361

Author(s):

Gabriel Gonzalez ◽

Jiří Grúz ◽

Cosimo Walter D’Acunto ◽

Petr Kaňovský ◽

Miroslav Strnad

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cell Death ◽

Neuronal Cell Death ◽

Disease Model ◽

Neuronal Cell ◽

Zeatin Riboside ◽

Neuroprotective Activity ◽

Protective Activity

Cytokinins are adenine-based phytohormones that regulate key processes in plants, such as cell division and differentiation, root and shoot growth, apical dominance, branching, and seed germination. In preliminary studies, they have also shown protective activities against human neurodegenerative diseases. To extend knowledge of the protection (protective activity) they offer, we investigated activities of natural cytokinins against salsolinol (SAL)-induced toxicity (a Parkinson’s disease model) and glutamate (Glu)-induced death of neuron-like dopaminergic SH-SY5Y cells. We found that kinetin-3-glucoside, cis-zeatin riboside, and N6-isopentenyladenosine were active in the SAL-induced PD model. In addition, trans-, cis-zeatin, and kinetin along with the iron chelator deferoxamine (DFO) and the necroptosis inhibitor necrostatin 1 (NEC-1) significantly reduced cell death rates in the Glu-induced model. Lactate dehydrogenase assays revealed that the cytokinins provided lower neuroprotective activity than DFO and NEC-1. Moreover, they reduced apoptotic caspase-3/7 activities less strongly than DFO. However, the cytokinins had very similar effects to DFO and NEC-1 on superoxide radical production. Overall, they showed protective activity in the SAL-induced model of parkinsonian neuronal cell death and Glu-induced model of oxidative damage mainly by reduction of oxidative stress.

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Stem Cell Therapy: A Promising Treatment of Parkinson’s Diseases

Pakistan Journal of Medicine and Dentistry ◽

10.36283/pjmd10-1/013 ◽

2021 ◽

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Disease Progression ◽

Dopaminergic Neurons ◽

Cellular Therapy ◽

Neurodegenerative Disorder ◽

Neuronal Degeneration ◽

Cell Types ◽

Parkinson’S Diseases ◽

Multipotent Mesenchymal Stem Cells

The neurodegenerative disorder is a prolonged persistence curse and effect on economic and physical challenges in an aging world. Parkinson has come in the second category of disability disorders and associated with progressive dopaminergic neuronal degeneration with severe motor complications. It is an observation that gradual disease progression causes 70% degeneration of striatal dopaminergic neurons. Globally there are around 7-10 million patients with Parkinson's disease, however, there are huge efforts for therapeutic improvement. According to studies, no single molecular pathway was pointed out as a single etiology to control disease progression due to a lack of targeted therapeutic strategies. Previously implemented symptomatic treatments include L-dopa (L-3,4-dihydroxyphenylalanine), deep brain stimulation, and the surgical insertion of a medical device. This leads to dyskinesia, dystonia and a higher risk of major surgical complications respectively. However, not all the above-mentioned therapies cannot regenerate the dopaminergic neurons in Parkinson’s disease patients. Recent advances in the field of cellular therapy have shown promising outcomes by differentiation of multipotent mesenchymal stem cells into dopaminergic neurons under the influence of a regenerative substance. In this review, we have discussed the differentiation of dopaminergic neurons by using different cell types that can be used as a cellular therapeutic approach for Parkinson’s disease. The information was collected through a comprehensive search using the keywords, “Parkinson Disease, Dopamine, Brain derived neurotrophic factor and neuron from reliable search engines, PubMed, Google Scholar and Medline reviews from the year 2010 to 2020.

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p53-dependent neuronal cell death in a DJ-1-deficient zebrafish model of Parkinson's disease

Journal of Neurochemistry ◽

10.1111/j.1471-4159.2006.04291.x ◽

2006 ◽

Vol 0 (0) ◽

pp. 070209222715077-??? ◽

Cited By ~ 15

Author(s):

Sandrine Bretaud ◽

Claire Allen ◽

Phillip W. Ingham ◽

Oliver Bandmann

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cell Death ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Zebrafish Model

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Neuroprotective Effects of Gagam-Sipjeondaebo-Tang, a Novel Herbal Formula, against MPTP-Induced Parkinsonian Mice and MPP+-Induced Cell Death in SH-SY5Y Cells

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2018/2420809 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Jade Heejae Ko ◽

Ju-Hee Lee ◽

Bobin Choi ◽

Ju-Yeon Park ◽

Young-Won Kwon ◽

...

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Cell Death ◽

Mitochondrial Dysfunction ◽

Apoptotic Cell ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Motor Dysfunction ◽

Herbal Formula ◽

Neuroprotective Effects

Parkinson’s disease is a neurodegenerative disease characterized by progressive cell death of dopaminergic neuron and following neurological disorders. Gagam-Sipjeondaebo-Tang (GST) is a novel herbal formula made of twelve medicinal herbs derived from Sipjeondaebo-Tang, which has been broadly used in a traditional herbal medicine. In the present study, we investigated the effects of GST against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced motor abnormalities in mice and 1-methyl-4-phenylpyridinium (MPP+)-induced neurotoxicity in SH-SY5Y cell. First, we found that GST alleviated motor dysfunction induced by MPTP, and the result showed dopaminergic neurons recovery in substantia nigra. In the cell experiment, pretreatment with GST increased the cell viability and attenuated apoptotic cell death in MPP+-treated SH-SY5Y cells. GST also inhibited reactive oxygen species production and restored the mitochondrial membrane potential loss, which were induced by MPP+. Furthermore, GST extract significantly activated ERK and Akt, cell survival-related proteins, in SH-SY5Y cells. The effect of GST preventing mitochondrial dysfunction was antagonized by pretreatment of PD98059 and LY294002, selective inhibitors of ERK and Akt, respectively. Taken together, GST alleviated abnormal motor functions and recovered neuronal cell death, mitochondrial dysfunction, possibly via ERK and Akt activation. Therefore, we suggest that GST may be a candidate for the treatment and prevention of Parkinson’s disease.

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LRRK2 links genetic and sporadic Parkinson's disease

Biochemical Society Transactions ◽

10.1042/bst20180462 ◽

2019 ◽

Vol 47 (2) ◽

pp. 651-661 ◽

Cited By ~ 41

Author(s):

Jillian H. Kluss ◽

Adamantios Mamais ◽

Mark R. Cookson

Keyword(s):

Parkinson’S Disease ◽

Parkinson's Disease ◽

Kinase Inhibitors ◽

Association Studies ◽

Neuronal Cell Death ◽

Neuronal Cell ◽

Vesicular Trafficking ◽

Common Mechanism ◽

Genome Wide Association Studies ◽

Functional Studies

Abstract The past two decades in research has revealed the importance of leucine-rich repeat kinase 2 (LRRK2) in both monogenic and sporadic forms of Parkinson's disease (PD). In families, mutations in LRRK2 can cause PD with age-dependent but variable penetrance and genome-wide association studies have found variants of the gene that are risk factors for sporadic PD. Functional studies have suggested that the common mechanism that links all disease-associated variants is that they increase LRRK2 kinase activity, albeit in different ways. Here, we will discuss the roles of LRRK2 in areas of inflammation and vesicular trafficking in the context of monogenic and sporadic PD. We will also provide a hypothetical model that links inflammation and vesicular trafficking together in an effort to outline how these pathways might interact and eventually lead to neuronal cell death. We will also highlight the translational potential of LRRK2-specific kinase inhibitors for the treatment of PD.

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