Therapeutic strategies in Parkinson's disease: what we have learned from animal models

Trends in parkinson's disease mortality in China from 2004 to 2021: a joinpoint analysis

BACKGROUND

This study aimed to analyze the trends of Parkinson's disease (PD) mortality rates among Chinese residents from 2004 to 2021, provide evidence for the formulation of PD prevention and control strategies to improve the quality of life among PD residents.

METHODS

Demographic and sociological data such as gender, urban or rural residency and age were obtained from the National Cause of Death Surveillance Dataset from 2004 to 2021. We then analyzed the trends of PD mortality rates by Joinpoint regression.

RESULTS

The PD mortality and standardized mortality rates in China showed an overall increasing trend during 2004-2021 (average annual percentage change [AAPC] = 7.14%, AAPCASMR=3.21%, P < 0.001). The mortality and standardized mortality rate in male (AAPC = 7.65%, AAPCASMR=3.18%, P < 0.001) were higher than that of female (AAPC = 7.03%, AAPCASMR=3.09%, P < 0.001). The PD standardized mortality rates of urban (AAPC = 5.13%, AAPCASMR=1.76%, P < 0.001) and rural (AAPC = 8.40%, AAPCASMR=4.29%, P < 0.001) residents both increased gradually. In the age analysis, the mortality rate increased with age. And the mortality rates of those aged > 85 years was the highest. Considering gender, female aged > 85 years had the fastest mortality trend (annual percentage change [APC] = 5.69%, P < 0.001). Considering urban/rural, rural aged 80-84 years had the fastest mortality trend (APC = 6.68%, P < 0.001).

CONCLUSIONS

The mortality rate of PD among Chinese residents increased from 2004 to 2021. Male sex, urban residence and age > 85 years were risk factors for PD-related death and should be the primary focus for PD prevention.

Association analysis of mitochondrial genome polymorphisms with backfat thickness in pigs

Mitochondrial DNA (mtDNA) variations and associated effects on economic traits have been widely reported in farm animals, as these genetic polymorphisms can affect the efficiency of energy production and cell metabolism. In studies related to metabolism, the deposition of fat was highly correlated with mitochondria. However, the effect of mtDNA polymorphisms on porcine backfat thickness (BFT) remained unclear. In this study, 243 pigs were collected to analyse the relationship between BFT and mtDNA polymorphisms. There were considerable differences in BFT, ranging from 5 mm to 18 mm. MtDNA D-loop sequencing discovered 48 polymorphic sites. Association analysis revealed that 30 variations were associated with BFT (P < 0.05). The polymorphism m.794A > G showed the maximum difference in BFT between A and G carriers, which differed at ∼2.5 mm (P < 0.001). The 48 polymorphic sites generated 22 haplotypes (H1-H22), which clustered into 4 haplogroups (HG1-HG4). HG1 had a lower BFT value than other three haplogroups (P < 0.01), whereas H4 in HG1 exhibited the lowest BFT of all haplotypes analyzed (P < 0.01). The results of this study highlight an association between mtDNA polymorphisms and BFT, and suggest the potential application of mtDNA in pig molecular breeding practices.

Role of Ceramides and Sphingolipids in Parkinson's Disease

Sphingolipids, including the basic ceramide, are a subset of bioactive lipids that consist of many different species. Sphingolipids are indispensable for proper neuronal function, and an increasing number of studies have emerged on the complexity and importance of these lipids in (almost) all biological processes. These include regulation of mitochondrial function, autophagy, and endosomal trafficking, which are affected in Parkinson's disease (PD). PD is the second most common neurodegenerative disorder and is characterized by the loss of dopaminergic neurons. Currently, PD cannot be cured due to the lack of knowledge of the exact pathogenesis. Nonetheless, important advances have identified molecular changes in mitochondrial function, autophagy, and endosomal function. Furthermore, recent studies have identified ceramide alterations in patients suffering from PD, and in PD models, suggesting a critical interaction between sphingolipids and related cellular processes in PD. For instance, autosomal recessive forms of PD cause mitochondrial dysfunction, including energy production or mitochondrial clearance, that is directly influenced by manipulating sphingolipids. Additionally, endo-lysosomal recycling is affected by genes that cause autosomal dominant forms of the disease, such as VPS35 and SNCA. Furthermore, endo-lysosomal recycling is crucial for transporting sphingolipids to different cellular compartments where they will execute their functions. This review will discuss mitochondrial dysfunction, defects in autophagy, and abnormal endosomal activity in PD and the role sphingolipids play in these vital molecular processes.

Neurodegenerative Disorders: Spotlight on Sphingolipids

Neurodegenerative diseases are incurable diseases of the nervous system that lead to a progressive loss of brain areas and neuronal subtypes, which is associated with an increase in symptoms that can be linked to the affected brain areas. The key findings that appear in many neurodegenerative diseases are deposits of proteins and the damage of mitochondria, which mainly affect energy production and mitophagy. Several causative gene mutations have been identified in various neurodegenerative diseases; however, a large proportion are considered sporadic. In the last decade, studies linking lipids, and in particular sphingolipids, to neurodegenerative diseases have shown the importance of these sphingolipids in the underlying pathogenesis. Sphingolipids are bioactive lipids consisting of a sphingoid base linked to a fatty acid and a hydrophilic head group. They are involved in various cellular processes, such as cell growth, apoptosis, and autophagy, and are an essential component of the brain. In this review, we will cover key findings that demonstrate the relevance of sphingolipids in neurodegenerative diseases and will focus on neurodegeneration with brain iron accumulation and Parkinson’s disease.

Role of Autophagy in Parkinson's Disease

Autophagy is an essential catabolic mechanism that delivers misfolded proteins and damaged organelles to the lysosome for degradation. Autophagy pathways include macroautophagy, chaperone-mediated autophagy and microautophagy, each involving different mechanisms of substrate delivery to lysosome. Defects of these pathways and the resulting accumulation of protein aggregates represent a common pathobiological feature of neurodegenerative disorders such as Alzheimer, Parkinson and Huntington disease. This review provides an overview of the role of autophagy in Parkinson's disease (PD) by summarizing the most relevant genetic and experimental evidence showing how this process can contribute to disease pathogenesis. Given lysosomes take part in the final step of the autophagic process, the role of lysosomal defects in the impairment of autophagy and their impact on disease will also be discussed. A glance on the role of non-neuronal autophagy in the pathogenesis of PD will be included. Moreover, we will examine novel pharmacological targets and therapeutic strategies that, by boosting autophagy, may be theoretically beneficial for PD. Special attention will be focused on natural products, such as phenolic compounds, that are receiving increasing consideration due to their potential efficacy associated with low toxicity. Although many efforts have been made to elucidate autophagic process, the development of new therapeutic interventions requires a deeper understanding of the mechanisms that may lead to autophagy defects in PD and should take into account the multifactorial nature of the disease as well as the phenotypic heterogeneity of PD patients.

Parkinson's disease-linked Parkin mutations impair glutamatergic signaling in hippocampal neurons

BACKGROUND

Parkinson's disease (PD)-associated E3 ubiquitin ligase Parkin is enriched at glutamatergic synapses, where it ubiquitinates multiple substrates, suggesting that its mutation/loss-of-function could contribute to the etiology of PD by disrupting excitatory neurotransmission. Here, we evaluate the impact of four common PD-associated Parkin point mutations (T240M, R275W, R334C, G430D) on glutamatergic synaptic function in hippocampal neurons.

RESULTS

We find that expression of these point mutants in cultured hippocampal neurons from Parkin-deficient and Parkin-null backgrounds alters NMDA and AMPA receptor-mediated currents and cell-surface levels and prevents the induction of long-term depression. Mechanistically, we demonstrate that Parkin regulates NMDA receptor trafficking through its ubiquitination of GluN1, and that all four mutants are impaired in this ubiquitinating activity. Furthermore, Parkin regulates synaptic AMPA receptor trafficking via its binding and retention of the postsynaptic scaffold Homer1, and all mutants are similarly impaired in this capacity.

CONCLUSION

Our findings demonstrate that pathogenic Parkin mutations disrupt glutamatergic synaptic transmission in hippocampal neurons by impeding NMDA and AMPA receptor trafficking. Such effects may contribute to the pathophysiology of PD in PARK2 patients.

ER Lipid Defects in Neuropeptidergic Neurons Impair Sleep Patterns in Parkinson's Disease

Parkinson's disease patients report disturbed sleep patterns long before motor dysfunction. Here, in parkin and pink1 models, we identify circadian rhythm and sleep pattern defects and map these to specific neuropeptidergic neurons in fly models and in hypothalamic neurons differentiated from patient induced pluripotent stem cells (iPSCs). Parkin and Pink1 control the clearance of mitochondria by protein ubiquitination. Although we do not observe major defects in mitochondria of mutant neuropeptidergic neurons, we do find an excess of endoplasmic reticulum-mitochondrial contacts. These excessive contact sites cause abnormal lipid trafficking that depletes phosphatidylserine from the endoplasmic reticulum (ER) and disrupts the production of neuropeptide-containing vesicles. Feeding mutant animals phosphatidylserine rescues neuropeptidergic vesicle production and acutely restores normal sleep patterns in mutant animals. Hence, sleep patterns and circadian disturbances in Parkinson's disease models are explained by excessive ER-mitochondrial contacts, and blocking their formation or increasing phosphatidylserine levels rescues the defects in vivo.

p13 protects against Parkinson's disease

Mitochondrial dysfunction is thought to contribute to Parkinson's disease progression, and factors that can overcome mitochondrial defects could potentially be used to combat the disease and prevent neuronal death. In this issue, Inoue et al 1 report that reduction of p13, a mitochondrial protein that inhibits complex I assembly, rescues the cellular and behavioral defects of Parkinson's disease models. This work suggests that stabilizing the mitochondrial electron transport chain may be beneficial in the context of Parkinson's disease.

Developing DNA methylation-based diagnostic biomarkers

An emerging paradigm shift for disease diagnosis is to rely on molecular characterization beyond traditional clinical and symptom-based examinations. Although genetic alterations and transcription signature were first introduced as potential biomarkers, clinical implementations of these markers are limited due to low reproducibility and accuracy. Instead, epigenetic changes are considered as an alternative approach to disease diagnosis. Complex epigenetic regulation is required for normal biological functions and it has been shown that distinctive epigenetic disruptions could contribute to disease pathogenesis. Disease-specific epigenetic changes, especially DNA methylation, have been observed, suggesting its potential as disease biomarkers for diagnosis. In addition to specificity, the feasibility of detecting disease-associated methylation marks in the biological specimens collected noninvasively, such as blood samples, has driven the clinical studies to validate disease-specific DNA methylation changes as a diagnostic biomarker. Here, we highlight the advantages of DNA methylation signature for diagnosis in different diseases and discuss the statistical and technical challenges to be overcome before clinical implementation.

Induced pluripotent stem cells in rat models of Parkinson's disease: A systematic review and meta-analysis

The effects of induced pluripotent stem cells (iPSCs) in 6-hydroxydopamine-lesioned rat models of Parkinson's disease (PD) have been evaluated in multiple studies. However, the results evaluating the effectiveness of iPSCs in animal models of PD are mixed, primarily due to their low statistical power. In the current study, a meta-analysis was performed to describe the treatment effect of unsorted iPSCs on behavioral testing in experimental rat models of PD. Databases searched included PubMed, EMBASE, MEDLINE and the Cochrane Library from inception to March 2017. Data were extracted for rotation behavior tests (induced by amphetamine and apomorphine) and limb function tests. A total of eight studies were included in the current meta-analysis, and iPSCs were identified to be efficacious according to the pooled standardized mean differences (SMDs) for improving amphetamine-induced rotational behavior [SMD, -2.16; 95% confidence interval (95% CI), -2.93, -1.40; P<0.00001] and apomorphine-induced rotational test (SMD, -1.45; 95% CI, -2.16, -0.73; P<0.0001). The pooled evidence indicated that iPSCs improve rotational behavior in rat models of PD. It was concluded that iPSCs provide a potential approach for developing novel treatment strategies for PD, and the results of this meta-analysis may guide future preclinical and clinical studies.

Inhibition of oxidative stress in cholinergic projection neurons fully rescues aging-associated olfactory circuit degeneration in Drosophila

Loss of the sense of smell is among the first signs of natural aging and neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Cellular and molecular mechanisms promoting this smell loss are not understood. Here, we show that Drosophila melanogaster also loses olfaction before vision with age. Within the olfactory circuit, cholinergic projection neurons show a reduced odor response accompanied by a defect in axonal integrity and reduction in synaptic marker proteins. Using behavioral functional screening, we pinpoint that expression of the mitochondrial reactive oxygen scavenger SOD2 in cholinergic projection neurons is necessary and sufficient to prevent smell degeneration in aging flies. Together, our data suggest that oxidative stress induced axonal degeneration in a single class of neurons drives the functional decline of an entire neural network and the behavior it controls. Given the important role of the cholinergic system in neurodegeneration, the fly olfactory system could be a useful model for the identification of drug targets.

Emerging preclinical pharmacological targets for Parkinson's disease

Parkinson's disease (PD) is a progressive neurological condition caused by the degeneration of dopaminergic neurons in the basal ganglia. It is the most prevalent form of Parkinsonism, categorized by cardinal features such as bradykinesia, rigidity, tremors, and postural instability. Due to the multicentric pathology of PD involving inflammation, oxidative stress, excitotoxicity, apoptosis, and protein aggregation, it has become difficult to pin-point a single therapeutic target and evaluate its potential application. Currently available drugs for treating PD provide only symptomatic relief and do not decrease or avert disease progression resulting in poor patient satisfaction and compliance. Significant amount of understanding concerning the pathophysiology of PD has offered a range of potential targets for PD. Several emerging targets including AAV-hAADC gene therapy, phosphodiesterase-4, potassium channels, myeloperoxidase, acetylcholinesterase, MAO-B, dopamine, A2A, mGlu5, and 5-HT-1A/1B receptors are in different stages of clinical development. Additionally, alternative interventions such as deep brain stimulation, thalamotomy, transcranial magnetic stimulation, and gamma knife surgery, are also being developed for patients with advanced PD. As much as these therapeutic targets hold potential to delay the onset and reverse the disease, more targets and alternative interventions need to be examined in different stages of PD. In this review, we discuss various emerging preclinical pharmacological targets that may serve as a new promising neuroprotective strategy that could actually help alleviate PD and its symptoms.

Deconvoluting the complexity of autophagy and Parkinson's disease for potential therapeutic purpose

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the preferential death of dopaminergic neurons. In the past two decades, great progress has been made toward understanding the pathogenesis of PD; however, its precise pathogenesis still remains unclear. Recently, accumulating evidence has suggested that macroautophagy (herein referred to as autophagy) is tightly linked to PD. Dysregulation of autophagic pathways has been observed in the brains of PD patients and in animal models of PD. More importantly, a number of PD-associated proteins, such as α-synuclein, LRRK2, Parkin and PINK1 have been further revealed to be involved in autophagy. Thus, it is now acknowledged that constitutive autophagy is essential for neuronal survival and that dysregulation of autophagy leads to PD. In this review, we focus on summarizing the relationships amongst PD-associated proteins, autophagy and PD. Moreover, we also demonstrate some autophagy-modulating compounds and autophagic microRNAs in PD models, which may provide better promising strategies for potential PD therapy.

Systematic analysis of genetic variants in Han Chinese patients with sporadic Parkinson's disease

Parkinson's disease (PD) is one of the most common neurodegenerative disorders. Accumulated evidence confirms that genetic factors play a considerable role in PD pathogenesis. To examine whether point variants or haplotypes are associated with PD development, genotyping of 35 variants in 22 PD-related genes was performed in a well-characterized cohort of 512 Han Chinese PD patients and 512 normal controls. Both Pearson's χ2 test and haplotype analysis were used to evaluate whether variants or their haplotypes were associated with PD in this cohort. The only statistically significant differences in genotypic and allelic frequencies between the patients and the controls were in the DnaJ heat shock protein family (Hsp40) member C10 gene (DNAJC10) variant rs13414223 (P = 0.004 and 0.002, respectively; odds ratio = 0.652, 95% confidence interval: 0.496-0.857). No other variants or haplotypes exhibited any significant differences between these two groups (all corrected P > 0.05). Our findings indicate that the variant rs13414223 in the DNAJC10 gene, a paralog of PD-related genes DNAJC6 and DNAJC13, may play a protective role in PD. This suggests it may be a PD-associated gene.

β-Ecdysterone Protects SH-SY5Y Cells Against 6-Hydroxydopamine-Induced Apoptosis via Mitochondria-Dependent Mechanism: Involvement of p38(MAPK)-p53 Signaling Pathway

Parkinson's disease (PD) is a neurological disorder pathologically characterized by loss of dopaminergic neurons in the substantia nigra. No curative therapy is available for PD. We recently found that phytoestrogen β-ecdysterone (β-Ecd) is able to reduce MPP(+)-induced apoptosis in PC12 cells. This study investigated the potential of β-Ecd to protect against SH-SY5Y cell apoptosis induced by the PD-related neurotoxin 6-hydroxydopamine (6-OHDA) and the underlying mechanism for this cytoprotection. In the present study, pretreatment with β-Ecd significantly reduced 6-OHDA-induced apoptosis of SH-SY5Y cells by a mitochondria-dependent pathway, as indicated by downregulation of Bax and PUMA (p53 upregulated modulator of apoptosis) expression, suppressing ΔΨm loss, inhibiting cytochrome c release, and attenuating caspase-9 activation. Furthermore, we showed that the inhibition of p38 mitogen-activated protein kinase (p38(MAPK))-dependent p53 promoter activity contributed to the protection of SH-SY5Y cells from apoptosis, which was validated by the use of SB203580 or p38β dominant negative (DN) mutants. Additionally, knock-down apoptosis signal-regulating kinase 1 (ASK1) by specific shRNA and blockade reactive oxygen species (ROS) by pharmacological inhibitor competently prevented β-Ecd-mediated inhibition of p38(MAPK) and ASK1 phosphorylation, respectively. These data provide the first evidence that β-Ecd protects SH-SY5Y cells against 6-OHDA-induced apoptosis, possibly through mitochondria protection and p53 modulation via ROS-dependent ASK1-p38(MAPK) pathways. The neuroprotective effects of β-Ecd make it a promising candidate as a therapeutic agent for PD.

Resequencing analysis of five Mendelian genes and the top genes from genome-wide association studies in Parkinson's Disease

Background

Most sequencing studies in Parkinson’s disease (PD) have focused on either a particular gene, primarily in familial and early onset PD samples, or on screening single variants in sporadic PD cases. To date, there is no systematic study that sequences the most common PD causing genes with Mendelian inheritance [α-synuclein (SNCA), leucine-rich repeat kinase 2 (LRRK2), PARKIN, PTEN-induced putative kinase 1 (PINK1) and DJ-1 (Daisuke-Junko-1)] and susceptibility genes [glucocerebrosidase beta acid (GBA) and microtubule-associated protein tau (MAPT)] identified through genome-wide association studies (GWAS) in a European-American case-control sample (n=815).

Results

Disease-causing variants in the SNCA,LRRK2 and PARK2 genes were found in 2 % of PD patients. The LRRK2, p.G2019S mutation was found in 0.6 % of sporadic PD and 4.8 % of familial PD cases. Gene-based analysis suggests that additional variants in the LRRK2 gene also contribute to PD risk. The SNCA duplication was found in 0.8 % of familial PD patients. Novel variants were found in 0.8 % of PD cases and 0.6 % of controls. Heterozygous Gaucher disease-causing mutations in the GBA gene were found in 7.1 % of PD patients. Here, we established that the GBA variant (p.T408M) is associated with PD risk and age at onset. Additionally, gene-based and single-variant analyses demostrated that GBA gene variants (p.L483P, p.R83C, p.N409S, p.H294Q and p.E365K) increase PD risk.

Conclusions

Our data suggest that the impact of additional untested coding variants in the GBA and LRRK2 genes is higher than previously estimated. Our data also provide compelling evidence of the existence of additional untested variants in the primary Mendelian and PD GWAS genes that contribute to the genetic etiology of sporadic PD.

Association of the MTHFR rs1801131 and rs1801133 variants in sporadic Parkinson's disease patients

Parkinson's disease (PD) is a common age-dependent neurodegenerative movement disorder related to multiple factors, and genetic factors play an important role in the pathogenesis of PD. Variants in the methylenetetrahydrofolate reductase gene (MTHFR), a gene encoding a folate-dependent enzyme that is involved in homocysteine metabolism, have been reported to be associated with PD. To explore the role of the MTHFR gene in the development of PD in Chinese Han population, we analyzed two MTHFR variants (rs1801131 and rs1801133) in a patient cohort consisting of 512 patients with PD from mainland China and a control cohort consisting of 512 age, gender and ethnicity matched normal subjects. Statistically significant differences in genotypic and allelic frequencies were detected in the MTHFR variant rs1801133 (P=0.022 and 0.007, respectively; odds ratio=0.780, 95% confidence interval=0.651-0.934). In addition, the A-T haplotype of rs1801131-rs1801133 showed a protective role against PD development (P=0.007, odds ratio=0.779, 95% confidence interval=0.650-0.933). Our results suggested that the T allele of rs1801133 variant and A-T haplotype of rs1801131-rs1801133 in the MTHFR gene may decrease the risk of developing PD in Chinese Han population from mainland China.

Induced pluripotent stem cells and Parkinson's disease: modelling and treatment

Many neurodegenerative disorders, such as Parkinson's disease (PD), are characterized by progressive neuronal loss in different regions of the central nervous system, contributing to brain dysfunction in the relevant patients. Stem cell therapy holds great promise for PD patients, including with foetal ventral mesencephalic cells, human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs). Moreover, stem cells can be used to model neurodegenerative diseases in order to screen potential medication and explore their mechanisms of disease. However, related ethical issues, immunological rejection and lack of canonical grafting protocols limit common clinical use of stem cells. iPSCs, derived from reprogrammed somatic cells, provide new hope for cell replacement therapy. In this review, recent development in stem cell treatment for PD, using hiPSCs, as well as the potential value of hiPSCs in modelling for PD, have been summarized for application of iPSCs technology to clinical translation for PD treatment.

Preclinical Evidence for a Role of the Nicotinic Cholinergic System in Parkinson's Disease

One of the primary deficits in Parkinson's disease (PD) is the loss of dopaminergic neurons in the substantia nigra pars compacta which leads to striatal dopaminergic deficits that underlie the motor symptoms associated with the disease. A plethora of animal models have been developed over the years to uncover the molecular alterations that lead to PD development. These models have provided valuable information on neurotransmitter pathways and mechanisms involved. One such a system is the nicotinic cholinergic system. Numerous studies show that nigrostriatal damage affects nicotinic receptor-mediated dopaminergic signaling; therefore therapeutic modulation of the nicotinic cholinergic system may offer a novel approach to manage PD. In fact, there is evidence showing that nicotinic receptor drugs may be useful as neuroprotective agents to prevent Parkinson's disease progression. Additional preclinical studies also show that nicotinic receptor drugs may be beneficial for the treatment of L-dopa induced dyskinesias. Here, we review preclinical findings supporting the idea that nicotinic receptors are valuable therapeutic targets for PD.

TCEANC2 rs10788972 and rs12046178 variants in the PARK10 region in Chinese Han patients with sporadic Parkinson's disease

Parkinson's disease (PD) is the second most common chronic neuronal degeneration disorder with motor and nonmotor clinical features. The rs10788972 variant of the transcription elongation factor A (SII) N-terminal and central domain containing 2 (TCEANC2) gene in the PARK10 region was recently identified to be strongly related to sporadic PD in the American population. To evaluate whether the same variant is associated with sporadic PD in Chinese Han population, we researched 513 sporadic PD patients and 512 normal controls of Chinese Han ethnicity in Mainland China. No significant difference in genotypic and allelic distributions between patients and control groups for either rs10788972 (for genotypic distribution, χ(2) = 0.412, p = 0.814, and for allelic distribution, χ(2) = 0.280, p = 0.597) or its neighbor marker rs12046178 (for genotypic distribution, χ(2) = 1.500, p = 0.472, and for allelic distribution, χ(2) = 1.339, p = 0.247) was found. Our data suggest that neither variant is related to sporadic PD in Chinese Han population.

Mitochondria: A Therapeutic Target for Parkinson's Disease?

Parkinson’s disease (PD) is one of the most common neurodegenerative disorders. The exact causes of neuronal damage are unknown, but mounting evidence indicates that mitochondrial-mediated pathways contribute to the underlying mechanisms of dopaminergic neuronal cell death both in PD patients and in PD animal models. Mitochondria are organized in a highly dynamic tubular network that is continuously reshaped by opposing processes of fusion and fission. Defects in either fusion or fission, leading to mitochondrial fragmentation, limit mitochondrial motility, decrease energy production and increase oxidative stress, thereby promoting cell dysfunction and death. Thus, the regulation of mitochondrial dynamics processes, such as fusion, fission and mitophagy, represents important mechanisms controlling neuronal cell fate. In this review, we summarize some of the recent evidence supporting that impairment of mitochondrial dynamics, mitophagy and mitochondrial import occurs in cellular and animal PD models and disruption of these processes is a contributing mechanism to cell death in dopaminergic neurons. We also summarize mitochondria-targeting therapeutics in models of PD, proposing that modulation of mitochondrial impairment might be beneficial for drug development toward treatment of PD.