Academic literature on the topic 'LRRK2 GENE'

Mutations in LRRK2 (leucine-rich repeat kinase 2) are associated with both familial and sporadic PD (Parkinson's disease). LRRK1 (leucine-rich repeat kinase 1) shares a similar domain structure with LRRK2, but it is not linked to PD. LRRK proteins belong to a gene family known as ROCO, which codes for large proteins with several domains. All ROCO proteins have a ROC (Ras of complex proteins) GTPase domain followed by a domain of unknown function [COR (C-terminal of ROC)]. LRRK2, LRRK1 and other ROCO proteins also possess a kinase domain. To date, the function of LRRK1 and both the physiological and the pathological roles of LRRK2 are only beginning to unfold. The comparative analysis of these two proteins is a strategy to single out the specific properties of LRRKs to understand their cellular physiology. This comparison is the starting point to unravel the pathways that may lead to PD and eventually to develop therapeutic strategies for its treatment. In the present review, we discuss recently published results on LRRK2 and its paralogue LRRK1 concerning their evolutionary significance, biochemical properties and potential functional roles.

In the period since LRRK2 (leucine-rich repeat kinase 2) was identified as a causal gene for late-onset autosomal dominant parkinsonism, a great deal of work has been aimed at understanding whether the LRRK2 protein might be a druggable target for Parkinson's disease (PD). As part of this effort, animal models have been developed to explore both the normal and the pathophysiological roles of LRRK2. However, LRRK2 is part of a wider family of proteins whose functions in different organisms remain poorly understood. In this review, we compare the information available on biochemical properties of LRRK2 homologues and orthologues from different species from invertebrates (e.g. Caenorhabditis elegans and Drosophila melanogaster) to mammals. We particularly discuss the mammalian LRRK2 homologue, LRRK1, and those species where there is only a single LRRK homologue, discussing examples where each of the LRRK family of proteins has distinct properties as well as those cases where there appear to be functional redundancy. We conclude that uncovering the function of LRRK2 orthologues will help to elucidate the key properties of human LRRK2 as well as to improve understanding of the suitability of different animal models for investigation of LRRK2-related PD.

LRRK2 gain-of-function is considered a major cause of Parkinson’s disease (PD) in humans. However, pathogenicity of LRRK2 loss-of-function in animal models is controversial. Here we show that deletion of the entire zebrafish lrrk2 locus elicits a pleomorphic transient brain phenotype in maternal-zygotic mutant embryos (mzLrrk2). In contrast to lrrk2, the paralog gene lrrk1 is virtually not expressed in the brain of both wild-type and mzLrrk2 fish at different developmental stages. Notably, we found reduced catecholaminergic neurons, the main target of PD, in specific cell populations in the brains of mzLrrk2 larvae, but not adult fish. Strikingly, age-dependent accumulation of monoamine oxidase (MAO)-dependent catabolic signatures within mzLrrk2 brains revealed a previously undescribed interaction between LRRK2 and MAO biological activities. Our results highlight mzLrrk2 zebrafish as a tractable tool to study LRRK2 loss-of-function in vivo, and suggest a link between LRRK2 and MAO, potentially of relevance in the prodromic stages of PD.

Leucine-rich repeat kinase 2 (LRRK2) gene mutation is an autosomal dominant mutation associated with Parkinson’s disease (PD). Among LRRK2 gene mutations, the LRRK2 G2019S mutation is frequently involved in PD onset. Currently, diverse gene correction tools such as zinc finger nucleases (ZFNs), helper-dependent adenoviral vector (HDAdV), the bacterial artificial chromosome-based homologous recombination (BAC-based HR) system, and CRISPR/Cas9-homology-directed repair (HDR) or adenine base editor (ABE) are used in genome editing. Gene correction of the LRRK2 G2019S mutation has been applied whenever new gene therapy tools emerge, being mainly applied to induced pluripotent stem cells (LRRK2 G2019S-mutant iPSCs). Here, we comprehensively introduce the principles and methods of each programmable nuclease such as ZFN, CRISPR/Cas9-HDR or ABE applied to LRRK2 G2019S, as well as those of HDAdV or BAC-based HR systems used as nonprogrammable nuclease systems.

The LRRK2 gene is the major genetic determinant of familiar Parkinson’s disease (PD). Leucine-rich repeat kinase 2 (LRRK2) is a multidomain protein involved in several intracellular signaling pathways. A wealth of evidence indicates that LRRK2 is enriched at the presynaptic compartment where it regulates vesicle trafficking and neurotransmitter release. However, whether the role of LRRK2 affects neuronal networks dynamic at systems level remains unknown. Addressing this question is critical to unravel the impact of LRRK2 on brain function. Here, combining behavioral tests, electrophysiological recordings, and functional imaging, we investigated neuronal network dynamics, in vivo, in the olfactory bulb of mice carrying a null mutation in LRRK2 gene (LRRK2 knockout, LRRK2 KO, mice). We found that LRRK2 KO mice exhibit olfactory behavioral deficits. At the circuit level, the lack of LRRK2 expression results in altered gamma rhythms and odorant-evoked activity with significant impairments, while the spontaneous activity exhibited limited alterations. Overall, our data in the olfactory bulb suggest that the multifaced role of LRRK2 has a strong impact at system level when the network is engaged in active sensory processing.

Mutations in the LRRK2 (leucine-rich repeat kinase 2) gene are the most frequent genetic cause of PD (Parkinson's disease), and these mutations play important roles in sporadic PD. The LRRK2 protein contains GTPase and kinase domains and several protein–protein interaction domains. The kinase and GTPase activity of LRRK2 seem to be important in regulating LRRK2-dependent cellular signalling pathways. LRRK2's GTPase and kinase domains may reciprocally regulate each other to direct LRRK2's ultimate function. Although most LRRK2 investigations are centred on LRRK2's kinase activity, the present review focuses on the function of LRRK2's GTPase activity in LRRK2 physiology and pathophysiology.

Missense mutations in the leucine-rich repeat kinase-2 (LRRK2) gene represent the most common cause of autosomal dominant Parkinson's disease (PD). In the years LRRK2 has been associated with several organelles and related pathways in cell. However, despite the significant amount of research done in the past decade, the contribution of LRRK2 mutations to PD pathogenesis remains unknown. Growing evidence highlights that LRRK2 controls multiple processes in brain immune cells, microglia and astrocytes, and suggests that deregulated LRRK2 activity in these cells, due to gene mutation, might be directly associated with pathological mechanisms underlying PD. In this brief review, we recapitulate and update the last LRRK2 functions dissected in microglia and astrocytes. Moreover, we discuss how dysfunctions of LRRK2-related pathways may impact glia physiology and their cross-talk with neurons, thus leading to neurodegeneration and progression of PD.

AbstractThe Leucine Rich Repeat Kinase 2 (LRRK2) is one of causative genes of familial Parkinson’s disease (PD). The M2397T polymorphism in LRRK2 is genetically associated with sporadic Crohn’s disease (CD). LRRK2 is expressed in human CD14+ monocytes, induced by interferon-γ (IFN-γ) and suppresses inflammatory activation. We hypothesize that IFN-γ-induced LRRK2 and inflammatory gene expression is altered by LRRK2 genetic polymorphism found in CD and PD cases. A total of 46 CD and 51 control cases, and 16 PD cases and 16 PD-linked LRRK2 mutation cases were recruited. Live human CD14+ monocytes were isolated from donors for ex vivo IFN-γ stimulation and gene expression analysis. IFN-γ potently enhanced TNFA, IL12, HLADRA1 and LRRK2 expression, which was suppressed by FK506, a calcineurin-specific inhibitor, but further enhanced by LRRK2-specific kinase inhibitor (GSK2578215A). The 2397-M/M CD risk allele enhanced IFN-γ responses of CD14+ cells in CD but not in control group. CD14+ monocytes from G2019S and R1441C LRRK2 mutated PD cases and carriers show no changes in IFN-γ responses for TNFA or IL12, reduced response for HLADRA1, and enhanced responses for LRRK2 in FK506-sensitive manner. These data demonstrate that CD-associated LRRK2 mutations are significant modifiers of innate immune response in CD14+ monocytes, and PD-associated LRRK2 mutation may contribute to reduced antigen presentation response.

Leucine rich-repeat kinase 2 (LRRK2) is the most well-known etiologic gene for familial Parkinson’s disease (PD). Its gene product is a large kinase with multiple functional domains that phosphorylates a subset of Rab small GTPases. However, studies of autopsy cases with LRRK2 mutations indicate a varied pathology, and the molecular functions of LRRK2 and its relationship to PD pathogenesis are largely unknown. Recently, non-autonomous neurodegeneration associated with glial cell dysfunction has attracted attention as a possible mechanism of dopaminergic neurodegeneration. Molecular studies of LRRK2 in astrocytes and microglia have also suggested that LRRK2 is involved in the regulation of lysosomal and other organelle dynamics and inflammation. In this review, we describe the proposed functions of LRRK2 in glial cells and discuss its involvement in the pathomechanisms of PD.

Parkinson’s disease is a neurodegenerative condition initially characterized by the presence of tremor, muscle stiffness and impaired balance, with the deposition of insoluble protein aggregates in Lewy’s Bodies the histopathological hallmark of the disease. Although different gene variants are linked to Parkinson disease, mutations in the Leucine-Rich Repeat Kinase 2 (LRRK2) gene are one of the most frequent causes of Parkinson’s disease related to genetic mutations. LRRK2 toxicity has been mainly explained by an increase in kinase activity, but alternative mechanisms have emerged as underlying causes for Parkinson’s disease, such as the imbalance in LRRK2 homeostasis and the involvement of LRRK2 in aggregation and spreading of α-synuclein toxicity. In this review, we recapitulate the main LRRK2 pathological mutations that contribute to Parkinson’s disease and the different cellular and therapeutic strategies devised to correct LRRK2 homeostasis. In this review, we describe the main cellular control mechanisms that regulate LRRK2 folding and aggregation, such as the chaperone network and the protein-clearing pathways such as the ubiquitin–proteasome system and the autophagic-lysosomal pathway. We will also address the more relevant strategies to modulate neurodegeneration in Parkinson’s disease through the regulation of LRRK2, using small molecules or LRRK2 silencing.

Microbiota’s influence on human health and disease is a growing research field including neurodegenerative diseases such as Parkinson’s disease (PD). The disease symptoms involve movement disorder, manifesting tremor, rigidity, bradykinesia and instability. At the molecular level, the disease exhibits; aggregated alfa-synuclein trapped inside neurons in the brain, in so called Lewy bodies, and loss of dopaminergic neurons in substantia nigra.The working hypothesis of this project is that human microbiome composition and interactions mediate environment and lifestyle influences on disease expression of PD. To validate this hypothesis, a mouse model (C57BL/J6 mice) was used. Two knock-in mouse lines were used; one carrying the wild type, human Leucine-Rich-Repeat-Kinase 2 (LRRK2) and the second carrying the most common Caucasian LRKK2/G2019S mutant. LRRK2 is a tyrosine kinase known to interact with Nucleotide-binding oligomerization domain-containing protein 2 (NOD2), a cytosolic microbe peptide sensing receptor. To establish the tools and knowledge required for the analyses, the initial part of the project was to analyze the expression levels of LRRK2 and NOD2 in wild-type C57BL/J6 mice in specific pathogen free (SPF), and mice devoid of exposure to living microbes, so called germ-free (GF) mice. Along with this analyse, expression levels of the transgenic LRKK2 proteins in the genetically modified mice was monitored. The focus was on the following tissues: striatum, midbrain, hippocampus, small intestine and large intestine and applied immune-histochemistry (IHC) combined with Western blot analysis.Results; significantly higher expression levels of LRRK2 were observed in microbe exposed mice versus GF mice with the exception of the large intestine which showed the opposite. Moreover, NOD2 showed a trend of lower expression levels in all brain GF areas tested with the exception to striatum. For the transgenic human knock-in LRKK2 proteins, increased expression of hLRKK2 were observed in striatum and large intestine compared to G2019S. Reduced hLRKK2 expression was observed in midbrain. The results suggest a strong correlation between LRRK2 expression and the gut microbiota and a need for continued research to better understand the role our indigenous microbiome may play in onset/progression of PD.
Mikroflorans betydelse för människors hälsa och sjukdomar är ett framväxande och banbrytande forskningsfält. Forskning har inte bara visat på mikroflorans betydelse för friska tillstånd utan också för utveckling av sjukdomar, så som Parkinsons sjukdom (PD). PD är en neurodegenerativ sjukdom med symptom som innefattar rörelsestörningar; tremor, stelhet, bradykinesi och instabilitet. På molekylär nivå ses aggregerat alfa-synuclein inuti neuroner i hjärnan, i så kallade Lewy-kroppar samt förlust av dopaminerga neuroner i substantia nigra.Hypotesen som utformats i detta projekt utgick ifrån att mikroflorans sammansättning och interaktioner, medierar miljö- och livsstilsfaktorer vilket leder till utveckling av PD. För att testa hypotesen användes musmodellen C57BL / J6 i vildtyp form samt i transgen form. De transgena formerna bestod av två olika knock-in modeller; en som bär den vilda typen av humant Leucin-Rich-Repeat-Kinase 2 (hLRRK2) och en som bär den vanligaste kaukasiska mutationen av samma protein, G2019S. LRRK2 är ett tyrosin kinas som interagerar med Nucleotide-binding-oligomerization-domain-containing-protein 2 (NOD2), en cytosolisk mikrobpeptidreceptor. Analyser av LRRK2 och NOD2 utfördes på vildtypen av C57BL / J6-möss i specifikt patogenfria (SPF) förhållanden samt på möss som saknar exponering för levande mikrober, så kallade bakteriefria (GF). I de transgena mössen analyserades de genetiskt modifierade LRKK2-proteinerna, hLRRK2 och G2019S, samt NOD2 i möss i SPF förhållanden. Följande vävnader undersöktes; striatum, mellanhjärnan, hippocampus, tunntarmen och tjocktarmen med immunhistokemi (IHC) i kombination med Western blot-analys.Resultaten visade på en betydligt högre uttrycksnivå av LRRK2 i mikrobexponerade möss jämfört med GF möss med undantag för tjocktarmen där resultatet visade det motsatta. Dessutom visade resultaten en trend på lägre uttrycksnivåer av NOD2 i alla analyserade områden i hjärnan med undantag för striatum. För de transgena humana knock-in-LRKK2-proteinerna observerades ökat uttryck av LRKK2 i striatum och tjocktarm jämfört med G2019S, samt reducerat LRKK2 uttryck i mellanhjärnan. Resultaten visar på en stark korrelation mellan LRRK2-uttryck och tarmens mikroflora och implicerar förbättrad förståelse av mikroflorans roll i början och under progression av PD.

Introdução: A Doença de Parkinson (DP) é a segunda doença neurodegenerativa mais comum. Os sintomas motores são decorrentes da morte de neurônios dopaminérgicos da Substância Nigra mesencefálica e por inclusões intracitoplasmáticas de ?-sinucleína, os corpúsculos de Lewy (CL). A doença pode ser o resultado de fatores ambientais agindo sobre um indivíduo geneticamente susceptível. O objetivo desse estudo foi verificar a frequência de mutações no gene PARK8/LRRK2 em uma amostra de pacientes brasileiros portadores de DP e descrever as principais correlações clínicas encontradas nos pacientes com mutações. Metodologia: Estudo transversal baseado no protocolo padronizado pelo projeto LARGE-PD (Latin American Research Consortium on The Genetics of PD) aplicado em 282 pacientes com DP recrutados de ambulatórios especializados em Distúrbios do Movimento do Hospital das Clínicas de Ribeirão Preto/USP e do Hospital São Paulo/UNIFESP, entre os anos de 2007 e 2014. O material genético colhido foi enviado para Seattle, com análise genética realizada no laboratório do Dr. Cyrus Zabetian da Universidade de Washington. Resultados: Realizado pesquisa genética para o LRRK2 em 229 pacientes de 282 pacientes que preencheram o protocolo. Quatro (1,74%) pacientes foram positivos para a mutação. Nos casos de inicio precoce, a frequência foi de apenas um caso (2,43% - 1/41). Três pacientes tinham história familiar positiva para DP (3,7% - 3/81). A idade de inicio dos sintomas variou entre 38 e 55 anos. A mutação G2019S esteve presente em 1,31% (3/229). Foi encontrado também um caso de mutação para R1441C. Conclusões: O LRRK2 se mostrou um importante gene correlacionado a DP, tendo como principal mutação a G2019S. O início dos sintomas variou entre 38 e 55 anos, sempre unilateral, com boa resposta a Levodopa.
Introduction: Parkinson\'s disease (PD) is the second most common neurodegenerative disease. Motor symptoms are due to the death of dopaminergic neurons in the midbrain Substance Nigra and intracytoplasmic inclusions known as Lewy bodies (CL), rich in a protein called ?-synuclein. The disease can be the result of environmental factors acting on an individual genetically susceptible, multifactorial etiology. The aim of this study was to determine the frequency of mutations in the gene PARK8 / LRRK2 in a sample of brazilian patients with PD and describe the main clinical correlations in patients with mutations. Methodology: This is a crosssectional study based on a standardized protocol for LARGE-PD project (Latin American Research Consortium on The Genetics of PD) applied in 282 patients with PD recruited from specialized clinics in Movement Disorders seen at Hospital das Clínicas de Ribeirão Preto/USP and Hospital São Paulo/UNIFESP, between the years 2007 and 2014. The genetic material was sent to Seattle, and genetic analysis was performed in the laboratory of Dr. Cyrus Zabetian at the University of Washington. Results: Realized genetic research for LRRK2 in 229 patients of 282 patients who met the LARGE-PD protocol. Observed four (1,74%) patients positive for the mutation. In cases of early-onset, the frequency was only one case (2,43% - 1/41). Three patients had a family history of PD (3,7% - 3/81). The age of onset of symptoms in patients with mutations varied between 38 and 55 years. A total of PD patients with the DNA analyzed, G2019S was present in 1,31% (3/229). It was also found one case to mutation R1441C. Conclusions: The LRRK2 had great influence gene correlated with PD, the main mutation G2019S. The onset of symptoms varied between 38 and 55 years, always one-sided, with good response to levodopa.

The leucine-rich repeat kinase 2 mutation (LRRK2) G2019S in the kinase-domain is the most common genetic cause of late-onset autosomal dominant Parkinson’s Disease (PD), occurring in >85% of patients carrying this LRRK2 mutation. LRRK2-related PD is clinically indistinguishable from the classic idiopathic form, being characterized by classic neuropathological hallmarks such as progressive degeneration of the substantia nigra pars compacta (SNpc) dopaminergic neurons, gliosis and α-synuclein and ubiquitine-positive intraneuronal cytoplasmic inclusions. The main goal of this thesis work was to evaluate the role played by the kinase function of LRRK2 in the expression of motor phenotype and dopamine transmission in mice, since transgenic models reported so far failed to recapitulate the parkinsonian phenotype and its neuropathology. To directly explore the impact of the kinase-enhancing G2019S mutation on motor activity in vivo, a longitudinal phenotyping approach was developed. We enrolled two cohorts of G2019S knock-in (KI) mice and wild-type littermates (WT) and analyzed their motor activity at different ages (3, 6, 10, 15 and 19 months) using a set of complementary behavioral tests, specific for akinesia, bradykinesia and overall gait ability. Our study revealed that G2019S KI mice motor performance remained stable up to the age of 19 months and did not show the typical age-related decline in immobility time and stepping activity of WT. To confirm that enhanced kinase activity accounts for this phenotype, we adopted a combined genetic and pharmacological approach. On one hand we performed a parallel longitudinal study in mice carrying a LRRK2 mutation (D1994S) that impairs kinase activity (kinase-dead, D1994S KD), on the other hand we administered two LRRK2 kinase inhibitors (H-1152 and Nov-LRRK2-11) in G2019S mice. We found that i) KD mice were not phenotypic and ii) LRRK2 inhibitors reversed the hyperkinetic phenotype of G2019S KI mice, while being ineffective in WT or in D1994S KD animals. In vivo LRRK2 targeting of kinase inhibitors was further substantiated by the reduction of LRRK2 phosphorylation at Ser935 in the striatum and/or cortex at efficacious doses of LRRK2 inhibitors. In order to investigate whether the hyperkinetic phenotype of G2019S mice was associated with dysfunction of striatal dopamine neurotransmission, we carried out a series of behavioral, biochemical, and neurochemical experiments. No changes in nigral dopamine cell counts or dopamine striatal density were observed in G2019S mice. However, the overall pattern of responses to a D2/D3 receptor agonist or antagonists and to D1/D5 receptor antagonists suggested an elevated tonic activation of dopamine receptors in G2019S KI mice. Furthermore, blockade of the dopamine transporter (DAT) resulted in an enhancement of motor performance of WT but not G2019S KI mice. Results from in vitro binding assays revealed a reduction in the DAT protein levels which was associated with an increased dopamine reuptake in G2019S KI mice. In vivo microdialysis showed a reduced metabolites/dopamine ratio in in the striatum of G2019S mice, suggesting a reduced dopamine turnover. Overall the data provide genetic and pharmacological evidence that the kinase activity of LRRK2 is highly implicated in the modulation of motor activity along with the striatal dopaminergic system. However, whether and how the observed changes in motor phenotype and dopamine transmission translate into the overt parkinsonian pathology remains a matter for speculation. It is also possible that G2019S KI mice reflect a pre-symptomatic stage of the disease, as observed in other genetic models of PD. Nonetheless, the present thesis work proposes G2019S KI mice as a valuable in vivo model to investigate the effects of LRRK2 inhibitors.

Conselho Nacional de Desenvolvimento Científico e Tecnológico
Parkinsons disease (PD) is the second most common neurodegenerative disease after Alzheimers disease, affecting nearly 1% of people above 65 years of age. The major clinical symptoms of this disease are: resting tremor, bradykinesia, rigidity, postural instability and a positive response to dopamine replacement therapy. Pathological findings include selective degeneration of dopaminergic neurons within the substantia nigra, with proteinaceous Lewy body inclusions in surviving cells. The pathogenesis of PD is not yet completely understood, however, both genetic and environmental factors contribute to the disease phenotype. Mutations in the leucine-rich repeat kinase 2 gene (LRRK2; OMIM 609007) represent the most frequent genetic known cause of familial and sporadic PD. The LRRK2 gene encodes a protein, member of the ROCO protein family, that contains both GTPase (ROC) domain and kinase (MAPKKK) domain, as well as, other motifs. In this study, we have screened the main domains of the LRRK2 in a group of 204 PD Brazilian patients. The screening was performed by direct sequencing of the PCR products. By the analysis of 14 exons corresponding to ROC, COR and MAPKKK domains, we identified 31 sequence variations. The novel variants, p.C1770R and p.C2139S, may play a role in the PD pathogenesis. Three exonic alterations (p.R1398R, p.T1410M and p.Y2189C) and nine intronic variants (c.4317+16C>T, c.5317+59A>C, c.5509+20A>C, c.5509+52T>C, c.5509+122A>G, c.5657-46C>T, c.6382-36G>A, c.6382-37C>T and c.6576+44T>C) seem to be not pathogenic. A total of 17 exonic and intronic alterations were previously described in the literature as non-pathogenic polymorphisms (p.R1398H, p.K1423K, p.R1514Q, p.P1542S, c.4828-31T>C, p.G1624G, p.K1637K, p.M1646T, p.S1647T, c.5015+32A>G, c.5170+23T>A, c.5317+32C>T, p.G1819G, c.5948+48C>T, p.N2081D, p.E2108E and c.6381+30A>G). The frequency of pathogenic mutations or potentially pathogenic variants was 3.4% (including the p.G2019S mutation, previously described in our previous report: Pimentel et al., 2008; Abdalla-Carvalho et al., 2010). In familial cases (11.1%) this frequency was approximately six times higher than in sporadic cases (1.8%). Our results suggest that LRRK2 mutations have an important contribution to PD development among Brazilian population.
A doença de Parkinson (DP) é a segunda doença neurodegenerativa mais frequente depois da Doença de Alzheimer, afetando aproximadamente 1% da população com idade superior a 65 anos. Clinicamente, esta doença caracteriza-se pela presença de tremor em repouso, bradicinesia, rigidez muscular e instabilidade postural, os quais podem ser controlados com a administração do levodopa. As características patológicas da DP incluem a despigmentação da substância nigra devido à perda dos neurônios dopaminérgicos e a presença de inclusões proteicas denominadas corpos de Lewy nos neurônios sobreviventes. As vias moleculares envolvidas com esta patologia ainda são obscuras, porém a DP é uma doença complexa, resultante da interação entre fatores ambientais e causas genéticas. Mutações no gene leucine-rich repeat kinase 2 (LRRK2; OMIM 609007) constituem a forma mais comum de DP. Este gene codifica uma proteína, membro da família de proteínas ROCO, que possui, entre outros domínios, dois domínios funcionais GTPase (ROC) e quinase (MAPKKK). Neste estudo, os principais domínios do gene LRRK2 foram analisados em 204 pacientes brasileiros com DP por meio de sequenciamento dos produtos da PCR. Através da análise de 14 exons correspondentes aos domínios ROC, COR e MAPKKK foram identificadas 31 variantes. As alterações novas, p.C1770R e p.C2139S, possuem um potencial papel na etiologia da DP. Três alterações exônicas (p.R1398R, p.T1410M e p.Y2189C) e nove intrônicas (c.4317+16C>T, c.5317+59A>C, c.5509+20A>C, c.5509+52T>C, c.5509+122A>G, c.5657-46C>T, c.6382-36G>A, c.6382-37C>T e c.6576+44T>C) são potencialmente não patogênicas. Ao todo, dezessete variantes exônicas e intrônicas constituem polimorfismos já relatados na literatura (p.R1398H, p.K1423K, p.R1514Q, p.P1542S, c.4828-31T>C, p.G1624G, p.K1637K, p.M1646T, p.S1647T, c.5015+32A>G, c.5170+23T>A, c.5317+32C>T, p.G1819G, c.5948+48C>T, p.N2081D, p.E2108E e c.6381+30A>G). A frequência total de alterações potencialmente patogênicas ou patogênicas detectadas em nossa amostra foi de 3,4% (incluindo a mutação p.G2019S, anteriormente descrita em 2 artigos publicados por nosso grupo: Pimentel et al., 2008; Abdalla-Carvalho et al., 2010), sendo a frequência de mutações nos casos familiares (11,1%) cerca de seis vezes maior do que a encontrada nos casos isolados da DP (1,8%). Os resultados alcançados neste estudo revelam que mutações no gene LRRK2 desempenham um papel significativo como fator genético para o desenvolvimento da DP em pacientes brasileiros.

Parkinson’s disease (PD) is one of the most common long-term degenerative disorders that affect the nervous system. Clinical symptoms are bradykinesia, resting tremor and postural imbalance due to the loss of dopaminergic neurons in the substantia nigra pars compacta. Heterozygous mutations in the Leucine Rich Repeat Kinase 2 gene (LRRK2) have been identified both in familial and sporadic cases of PD. The most common variant is the p.Gly2019Ser substitution (c.6055G>A). To date there is no effective treatment available. The genome editing tool CRISPR/Cas9 has recently transformed the field of biotechnology and biomedical discovery, posing the basis for the development of innovative treatments. Using CRISPR/Cas9 technology and Homology Directed Repair, our project aims to validate gene editing as an alternative therapeutic approach for PD through the genetic correction of the pathogenic p.Gly2019Ser LRRK2 mutation restoring the wild-type sequence both in human and mouse models. Specifically, we tested various strategies, based on the CRISPR/Cas9-based genome editing technique, for the correction of LRRK2 p.Gly2019Ser (c.6055G>A) variant in primary mouse and human fibroblasts with promising results. If the correction experiments in in vitro models will confirm the good efficiency of the approach, these experiments will represent a fundamental step for the subsequent evaluation of the potential of gene therapy for the treatment of PD as well as other brain disorders for which no therapy is currently available.

Parkinson’s disease is an insidious neurodegenerative disease, for which there are no reliable pre-symptomatic biomarkers or preventative therapies. While mostly sporadic, approximately 15% of PD cases report an affected first-degree relative. The study of these patients, and those that belong to larger multi-incident families, have previously identified a number of rare genetic causes of disease. The characterisation of these genes and proteins have uncovered novel underlying molecular mechanisms involved in disease, which has facilitated the investigation of novel therapeutic interventions. Further, the study of affected and asymptomatic carriers of these mutations benefit biomarker research. To this end, this study has screened and reported on subjects with known genetic causes of disease from the Queensland Parkinson’s Project (QPP). These include two VPS35 p.D620N kindreds, eleven LRRK2 p.G2019S kindreds and one phenocopy, two SNCA duplication kindreds and four kindreds with PARK2 mutations, two of which had seemingly dominant inheritance. Additionally, this study also conducted gene hunting analyses to identify novel high impact genetic mutations that are sufficient to cause parkinsonism. Initially, a prioritisation and genetic pre-screening model was established to select families that had the highest potential to identify novel causes of disease. The model considered the number of, and the relationships between, affected members, as well as the likelihood of recruiting more family cases. Then genetic pre-screening investigated copy number variations, polymorphic nucleotide expansions as well as employing initial whole exome sequencing to identify possible causes of disease. The results from this analysis identified eleven multi-incident families suitable for next generation sequencing in multiple affected members. Whole exome sequencing was coupled with supportive evidence such as variant frequency, differential expression in an in vitro disease model and genotype analysis of other cases to identify the most likely candidates for disease. While more evidence of causality is required, the KCNJ15 p.R28C mutation was found to segregate with disease in a kindred consisting of nine affected members, as well as being identified in two additional patients, one sporadic case from Queensland, Australia, and one Italian familial case. Further, the SIPA1L1 p.R236Q mutation was identified in members from one multiincident family and one familial case. While, analysis of de novo arising mutations in an early onset case identified the novel FAM134B p.D381V mutation as a candidate for disease. Analysis of a family with multiple movement disorders identified a number of possible candidates, which require further investigation in other multiple systems atrophy, essential tremor, dystonic and PD cases. Furthermore, this study has also collated putative PD genes from the literature, and examined their segregation within the multi-incident families of the QPP. A number of mutations in these genes were identified to segregate, at least partially, with disease. However, considerable more evidence is required before their role in disease can be determined. The study of multi-incident families provides valuable insights into genetic aberrations that are sufficient to cause disease. The investigation of these monogenic forms of disease allow for the characterisation of molecular processes that may lead to disease. Indeed, the putative genetic targets identified in this study may improve our understanding of molecular pathways involved in parkinsonism, which may consequently aid in the development of novel therapies or biomarkers.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Background: Although Parkinson’s disease (PD) is commonly described as a motor disorder, non-motor symptoms and cardiovascular dysautonomia are important factors of disability and impaired quality of life in PD patients. To date, the definite correlation of cardiovascular symptoms with motor and other non-motor symptoms of PD are still largely unclear. Besides, the discovery of genetic mutations related to PD, such as LRRK2 mutations, provides better possibility to identify specific phenotypes both for motor and non-motor symptoms. Obiectives: The main objective of our study was directed to investigate the presence and the correlation of cardiovascular dysautonomia with other non-motor symptoms in PD patients, with with or without LRRK2 mutations. Finally, we performed a study of heart rate variability (HRV) and exercise stress echocardiography with the attempt to investigate dysautonomia in these groups of patients. Methods: Forty fifteen Sardinian PD patients (240 men and 165 women) were included in the study. PD patients were screened for the presence of LRRK2 mutations. Motor impairment and disability were assessed using the Hoehn & Yahr staging and the Unified PD Rating Scale (UPDRS) part-III. Cardiovascular symptoms and other non-motor symptoms were assessed with the Non-Motor Symptoms Scale (NMSS). Correlations between cardiovascular symptoms and other PD features were studied. Heart rate variability (HRV) and exercise stress echocardiography were performed in two subgroups of patients (with or without LRRK2 mutations) and in a control group, matched for age and gender. Results: Cardiovascular symptoms were among the five non-motor symptoms more reported and were correlated with multiple non motor symptoms, especially with fatigue and loss of weight. PD patients with LRRK2 mutations reported less severity of cardiovascular symptoms. HRV revealed reduced LF/HF ratio both in PD patients with or without LRKK2 mutations, with enhancement of HF in LRRK2 patients. Cardiovascular symptoms detected at NMSS correlated with LF/HF ratio. Echocardiography show a Δ Strain rate reduced in parkinsonian patients. Δ Strain rate was also correlated with the LF/HF ratio in the LRRK2 group. Discussion: The better assessment of non-motor and cardiovascular symptoms in PD patients with and without LRRK2 mutation, both with the systematic administration of symptomatic scales, such as the NMSS, and with a combined approach with HRV and exercise stress echocardiography, might lead to the detection of better monitoring systems and to the possible improvement of current strategies used in the treatment of these disabling conditions.

Inter-organelle communication is a key feature of eukaryotic cells and has been found to be fundamental in many different cellular processes. One of the best characterized interorganelle cross talk due to membrane contact sites is that between Endoplasmic Reticulum (ER) and mitochondria. Also referred to as mitochondria associated ER-membranes (MAMs) or Mitochondria-ER contact sites (MERCs), their existence was discovered 50 years ago through electron microscopic studies, but their functional significance started to emerge only in late 90s when the role of MERCs in calcium exchange from ER to mitochondria was demonstrated. Despite the importance of these contacts sites in physiology and pathology, only few proteins have so far been identifed involved in the structural maintenace of the distance between the two organelles in mammals. Mitofusin 2 (MFN2) was the first structural tether to be identified. MFN2 has been found on both OMM and ER cytosolic face and is able to form homo and heterotypic interactions with MFN1, thus tethering the two organelles. As residual juxtaposition between the two organelles is still observed in Mfn2-/- cells, additional tethering proteins have to exist. To identify them, we set out to perform two replicates of a genome wide screening in mouse embryonic fibroblasts (MEFs). In order to perform the genome wide screening, we capitalized on the FRET based biosensor, where CFP fused with FRB domain and YFP fused with FKBP domain were targeted to ER (by a Sac 1 signaling sequence) and mitochondria (by an Akap signaling sequence) respectively (Csordas et al., 2010). We modified this probe by introducing between the cDNAs of the two fluorescent proteins a self-cleaving Tav2A peptide in order to have a single mRNA construct that allows the expression of equimolar level of the proteins. FKBP and FRB binding domain are able to heterodymerize upon addition of rapamycin, thus allowing the measurement not only of the basal level of juxtaposition between the two organelles, but also of the maximum level of contacts that can occur in a cell. We called this new construct FRET ER-mitochondria probe (FEMP). FEMP unique features allow us to discriminate between proteins whose role is keeping the two organelles closer, termed as "tethers", and proteins that keep the two organelles apart, defined as "spacers". We analyzed raw images from the screen and calculated two indexes, namely basal and maximum MERC index, mirroring the level of contacts observed at any given timepoint and the maximum possible level of contacts respectively. Following automated image analysis and statistical analysis performed on ~10,000 genes, after candidate selection we identified 205 genes as ER-mitochondria tethers (i.e., genes that once ablated increase the distance between the two organelles) and 59 genes as spacers (i.e., genes that once ablated decrease the distance between the two organelles) affecting both basal and maximum MERC index in both replicates. Moreover, we identified 625 tehters and 696 spacers affecting only the basal MERC index; 519 tethers and 67 spacers affecting only the maximum MERC indexes. Protein classes analysis of these three groups of genes by Panther predicted both already known and new protein classes that are yet to explored in terms of ER-mitochondria communication. Subcellular localization analysis to identify predicted proteins to be present in both ER and outer mitochondrial membrane (OMM) of the gene lists detailed before, revealed 13 proteins among the common tethers and spacers, 30 proteins affecting only the basal MERC index and 16 proteins affecting only the maximum MERC index localized on both organelles. One of the protein present in the last group is Leucine Rich Repeat Kinase 2 (LRRK2) and we have further characterized it as ER-mitochondria tether. Subcellular fractionation experiments showed that LRKK2 localized mostly in MAMs. As expected for a tether, levels of ER-mitochondria juxtaposition, measured with FEMP, were decrased in LRRK2-/- MEF. ER-mitochondria proximity was fully restored by reintroduction in MEF LRRK2-/- of wt protein but not of the familial PD associated mutants. In conclusion, we have developed a new method to assess the proximity between ER and mitochondria and we have utilized this technology to perform two replicates of a high content screen identifying novel structural components of the ER-mitochondria contact sites.
La comunicazione tra organelli cellulari è una caratteristica fondamentale delle cellule eucariotiche ed esercita un ruolo fondamentale in molti processi cellulari. Uno dei processi di comunicazione tra organelli cellulari tra i più caratterizzati è quello dovuto ai siti di contatto tra le membrane di mitocondri e reticolo endoplasmatico (ER). Anche noti come "Mitochondria-associated ER membranes" (MAMs) o "Mitochondria-ER contact sites" (MERCs), la loro esistenza è stata scoperta 50 anni fa tramite studi di microscopia elettronica, ma il loro significato funzionale è iniziato ad emergere solo alla fine degli anni 90 quando è stato dimosdtrato il ruolo dei MERCs nello scambio di calcio dall'ER. Nonostante l'importanza di questi siti di contatto tra organelli sia in fisiologia sia in patologia, solo poche proteine coinvolte nel mantenimento strutturale della distanza tra i due organelli sono state finora identificate nei mammiferi. Mitofusina2 (MFN2) è stato il primo "tether" strutturale ad essere identificato. E' stato rilevato che MFN2 è localizzata sia nella membrana mitocondriale esterna (OMM) sia sulla superficie citosolica dell'ER ed ' in grado di formare intrazioni omo- ed eterotipiche con MFN1, mantenendo quindi la distanza tra i due organelli. Poiché una residua giustapposizione tra i due organelli è stata osservata in cellule MFN2-/-, ulteriori proteine che esercitano questo ruolo devono esistere. Per identificarle, abbiamo stabilito un protocollo ed eseguito due repliche di uno screening genomico su larga scala in fibroblasti embrionali di topo (MEF). Per eseguire questo screening, abbiamo sfruttato un biosensore basato sulla FRET, dove la proteina fluorescente CFP fusa con il dominio funzionale FRB e la proteina fluorescente YFP fusa con il dominio funzionale FKBP vengono fatte localizzare rispettivamente all'ER (grazie alla sequenza di segnale Sac1) ed ai mitocondri (grazie alla sequenza di segnale Akap1) (Csordas G. et al., 2010). Abbiamo modificato questo costrutto inserendo tra i cDNA delle due proteine il peptide autocatalitico Tav2A per ottenere un singolo mRNA e quindi l'espressione equimolare delle due proteine. I domini funzionali FKBP e FRB sono in grado di eterodimerizzare con l'aggiunta di Rapamicina, permettendo così la misurazione non solo dei livelli di giustapposizione basale tra i due organelli, ma anche del massimo livello di contatti che possono avvenire in una cellula. Abbiamo chiamato questo nuovo costrutto FRET ER-mitochondria probe (FEMP). Le caratteristiche uniche del FEMP ci consentono didiscriminare tra le proteine il cui ruolo è quello di mantenere i due organelli vicini, chiamate "tethers", e proteine che invece tengono i due organelli più distanti, definiti "spacers". Le immagini ottenute dallo screening sono state analizzate e sono stati calcolati due indici, chiamati "basal MERC index" e "maximum MERC index", che rappresentano rispettivamente il livello di contatti osservabili in qualsiasi momento in una cellula e il massimo livello di contatti possibile. A seguito di un'analisi delle immagini automatizzata e di un'analisi statistica effettutata su ~10,000 geni, dopo un processo di selezione abbiamo identificato 205 geni come "tethers" (geni che una volta eliminati aumentano la distanza tra i due organelli) tra mitocondri e ER e 59 geni come "spacers" (geni che una volta eliminati diminuiscono la distanza tra i due organelli) che influenzano sia il basal sia il maximum MERC index in entrambe le repliche. Inoltre, sono stati identificati 625 tethers e 696 spacers che influenzano solo il basal MERC index; e 519 tethers e 67 spacers che modificano solo il maximum MERC index. Analisi delle classi di proteine presenti in questi tre gruppi tramite Panther ha rivelato sia classi di proteine il cui ruolo in questo processo era noto, sia nuove classi di proteine il cui ruolo nella comunicazione tra ER e mitocondri deve ancora essere esplorato. Analisi della localizzazione cellulare per identificare proteine localizzate sia nell'ER sia nei mitocondri delle liste di geni esposte in precedenza, ha rivelato l'esistenza di 13 proteine tra i tethers e gli spacers comuni, 30 proteine che influenzano solo il basal MERC index e 16 proteine che influenzano solo il maximum MERC index localizzate in entrambi gli organelli. Una delle proteine presente nell'ultimo gruppo è "Leucine Rich Repeat Kinase 2" (LRRK2) che abbiamo ulteriormente caratterizzato come tether tra ER e mitocondri. Esperimenti di frazionamento cellulare dimostrano che LRRK2 è localizzata principalmente nelle MAMs. Come previsto per un tether, il livello di prossimità tra ER e mitocondri, misurato tramite FEMP, sono diminuiti in MEF LRRK2-/-. La prossimità tra i due organelli è pienamente recuperata dalla reintroduzione in MEF LRRK2-/- della proteina WT, ma non dei mutanti associati alle forme di Parkinson familiare. In conclusione, abbiamo sviluppato un nuovo metodo per determinare la prossimità tra ER e mitocondri e abbiamo utilizzato questa tecnologia per eseguire due repliche di uni screening gnomico su larga scala identificando nuovi componenti strutturali dei contatti tra mitocondri e ER.

Conselho Nacional de Desenvolvimento Científico e Tecnológico
A doença de Parkinson (DP) é a segunda doença neurodegenerativa mais frequente no mundo, afetando 1-2% da população acima de 65 anos, caracterizada clinicamente por tremor em repouso, bradicinesia, instabilidade postural e rigidez muscular. Essas manifestações surgem devido à degeneração neuronal progressiva e à presença de inclusões proteicas ricas em α-sinucleína. A DP é decorrente da interação entre fatores ambientais e genéticos, e entre os fatores genéticos, variantes exônicas de transmissão dominante nos genes LRRK2 (leucine-rich repeat kinase 2), VPS35 (vacuolar protein sorting 35) e EIF4G1 (eukaryotic translation initiation factor 4-gamma 1) têm sido associadas à etiologia da doença. Entretanto, estudos sobre o efeito dessas variantes na população brasileira são raros ou inexistentes. Por essa razão, neste trabalho rastreamos mutações nos genes VPS35 (p.D620N; p.R524W), EIF4G1 (p.R1205H; p.A502V) e LRRK2 (p.G2019S) em uma amostra de 582 pacientes brasileiros com DP não aparentados e 329 indivíduos controles saudáveis. Além disso, conduzimos o primeiro estudo caso-controle para análise de variantes exônicas raras (p.Q1111H, p.T1410M, p.M1646T, p.S1761R, p.Y2189C) e comuns (p.N551K, p.R1398H, p.K1423K) no gene LRRK2 em um subgrupo de 329 pacientes brasileiros com DP, não aparentados, naturais da região sudeste. Esse subgrupo foi analisado e comparado com 222 indivíduos controles saudáveis a fim de verificar associações dessas variantes e a DP. Em relação às mutações dos genes VPS35 e EIF4G1, não foram encontradas alterações nos pacientes com DP. A mutação p.G2019S no gene LRRK2 foi encontrada em 15 probandos (2,6%), dos quais 9 são do sexo feminino (64,3%). O tremor em repouso foi observado em 47,36% dos pacientes com a mutação p.G2019S como primeiro sintoma motor. As análises das variantes raras no gene LRRK2 não revelaram qualquer associação estatisticamente significante. Entre as variantes comuns, a p.K1423K mostrou evidência de associação de risco com a DP (p<0,05) na estratificação contendo o grupo de indivíduos com história familiar da doença e para as variantes p.N551K e p.R1398H não foram observadas associações. A análise do haplótipo p.N551K-p.R1398H-p.K1423K revelou associação de proteção na amostra sudeste e na estratificação Rio de Janeiro (p<0,05). Esse haplótipo não está em desequilíbrio de ligação na amostra de 222 indivíduos controles brasileiros analisados (r2≤45). Os resultados obtidos neste estudo representam contribuições valiosas ao entendimento da relação entre as variantes genéticas estudadas e o risco de desenvolvimento da doença de Parkinson, principalmente no que se refere aos endofenótipos associados.
Parkinsons disease (PD) is the second most common neurodegenerative disorder in the world, affecting 1-2% of population more than 65 years of age, clinically recognized by resting tremor, bradykinesia, postural instability and rigidity. These manifestations occur due to progressive neuronal degeneration and to the presence of protein inclusions enriched with α-synuclein. PD results from the interaction between environmental and genetic factors, and, among genetic factors, dominant exonic variants in LRRK2 (leucine-rich repeat kinase 2), VPS35 (vacuolar protein sorting 35) e EIF4G1 (eukaryotic translation initiation factor 4-gamma 1) genes have been described as causes of the disease. However, studies of the effect of these variants in Brazilian population are rare or do not exist. For this reason, in this study we decided screening mutations in VPS35 (p.D620N; p.R524W), EIF4G1 (p.R1205H; p.A502V) and LRRK2 (p.G2019S) genes in a cohort of 582 unrelated Brazilian patients with PD and 329 healthy individuals control. In additional, we carried on the first case-control study to analyze LRRK2 exonic rare (p.Q1111H, p.T1410M, p.M1646T, p.S1761R, p.Y2189C) and common (p.N551K, p.R1398H, p.K1423K) variants in a subgroup of 329 unrelated Brazilian patients with PD from Southeastern region. This group was analyzed and compared to 222 healthy individuals control in order to verify associations between these variants and PD. Regarding mutations of VPS35 and EIF4G1 genes, we have not found any alteration in Brazilian patients with PD. The mutation p.G2019S in LRRK2 gene was found in 15 probands (2.6%), 9 of them are female (64,3%). Resting tremor was observed in 47,36% of p.G2019S patients as the predominant initial symptom. Regarding the LRRK2 rare variants, the results showed no significant association. Among LRRK2 common variants, the p.K1423K showed evidence of risk association with PD (p<0,05) in the stratified analysis concerning the group of patients with family history of the disease, in contrast, p.N551K and p.R1398H variants showed no associations. The analysis of p.N551K-p.R1398H-p.K1423K revealed protection in Southeastern group and Rio de Janeiro stratification (p<0,05). This haplotype is not in disequilibrium linkage in 222 Brazilian healthy individuals control analyzed (r2≤45). Results obtained in this research represent valuable contributions for the understanding of association between the genetic variants studied and the risk of developing PD, particularly with regard to the associated endophenotypes.

Parkinson's Disease (PD) is the second most common neurodegenerative disorder, characterized by the progressive loss of neurons beginning in the ventral midbrain, eventually spreading to higher cortical areas. Animal models of PD must recapitulate a complex set of motor and non-motor alterations that are the result of degeneration of widespread neuronal circuits and neurotransmitter systems. As expected, no one model has been devised that exhibits all clinical features of PD. Nevertheless, there are multiple model systems that have been developed that accurately reflect specific pathological, neurochemical, or neurophysiological disruptions that have allowed investigators to better understand aspects of the pathogenesis of PD, and begin to develop both symptom-targeted as well as neuroprotective therapeutic strategies. Multiples genetic approaches exist to model the rare familial autosomal dominant (e.g. transgenic and targeted over-expression of the mutant gene of interest; á-synuclein or LRRK2); and recessive cases of PD (targeted deletion of the relevant gene; e.g. parkin, DJ-1, etc.). Alternatively, toxins causing broad or dopamine neuron-specific mitochondrial dysfunction have been employed to model the complex I deficiency reported in sporadic cases of PD; or those that impair proteasomal-based protein degradation effectively model the formation of neuronal Lewy bodies. In this chapter we will present each class of PD animal model, their strengths and weaknesses, as well as insights gained from these approaches into the pathogenesis and treatment of PD.

Context: Parkinsonism is a clinical syndrome characterized by bradykinesia, tremor at rest, muscle stiffness and postural instability. Parkinson’s disease is the most common cause of parkinsonism. Pathogenic mutations in the leucine- rich repeat kinase 2 gene (LRRK2) have been identified in PARK8-linked autosomal dominant parkinsonism. This mutation is the most common and explains about 1–7% of family cases of parkinsonism of European and American origin and 1–3% of sporadic PD. This case report was approved by the Ethics Committee of Universidade Metropolitana de Santos. Case Report: The present case relates to a 40-year-old, white man, who presented insidious and progressive parkinsonism for 6 years, akinetic-rigid and asymmetric (Hoehn Yahr 2.5 scale) associated with early camptocormia and non-motor symptoms and partial response to levodopa. The classic phenotype of late-onset parkinsonism was found on the paternal side of the patient’s family, suggesting family inheritance. Exome sequencing showed heterozygous mutation PARK8 LRRK2 (Gly2019Ser). Conclusions: The presentation of this case was aimed at alerting to Parkinson’s genetic disease in adults with family inheritance associated with early camptocormia. The presentation of this case was aimed at alerting to Parkinson’s genetic disease in adults with family inheritance associated with early camptocormia.

Introdução: A doença de Parkinson (DP) apresenta etiologia multifatorial, que inclui disfunções genéticas e ambientais. Resulta da perda progressiva de células produtoras de dopamina na substância negra e do acúmulo de proteínas, principalmente a alfa-sinucleína (SNCA), nos corpos de Lewy. Esses aspectos levam a sintomatologia de bradicinesia, tremor de repouso e rigidez. Neurônios dopaminérgicos necessitam de demanda energética, assim, distúrbios mitocondriais, como bioenergéticos, mutações no DNA nuclear ou mitocondrial, alterações no transporte, movimento e morfologia dessa organela, estão associados à DP. Objetivo: Esclarecer a relação de distúrbios mitocondriais e o desenvolvimento da DP. Materiais e Métodos: Revisão bibliográfica da literatura realizada na bases de dados PubMed/MEDLINE, durante abril e maio de 2021, por meio do cruzamento dos descritores, cadastradas no DeCS, “Parkinson Disease” AND “Mitochondria”. Foram incluídos artigos com textos disponíveis completos gratuitamente, publicados nos últimos cinco anos, em inglês e português, com o estudo envolvendo humanos e excluídos aqueles cujo título ou resumo eram incoerentes com a linha de interesse da atual revisão. Com base nisso, encontraram-se 106 artigos, dos quais 8 foram selecionados, além de outros 2 e um livro didático, julgados importantes para a discussão do tema. Resultados: Evidências científicas mostram que mutações nos genes SNCA, LRRK2, Parkin e PINK1 implicam em mecanismos mitocondriais deficitários que desenvolvem a DP. A mutação do gene SNCA sensibiliza neurônios ao estresse oxidativo e provoca danos por toxinas, o que induz a fragmentação mitocondrial e a produção de radicais livres. A PARKIN previne o edema e a ruptura mitocondrial secundária à toxicidade, ou seja, relaciona-se à integridade mitocondrial. Alterações na proteína PINK1 interferem no potencial da membrana mitocondrial. Ademais, mutações na quinase LRRK2 interferem no tráfego mitocondrial e nas proteínas da membrana externa. Logo, modificações nesses genes além de diminuírem a atividade do complexo I da cadeia transportadora de elétrons, prejudicam a produção energética, a regulação da síntese de dopamina e sua neurotransmissão. Conclusão: De acordo com a literatura, observa-se a fundamental relação entre DP e disfunções mitocondriais, todavia mais estudos são necessários para esclarecer e justificar tal abordagem, como forma de melhorar o prognóstico e a terapêutica.

Introduction: Parkinson’s disease (PD) is characterized by the degeneration and loss of dopaminergic neurons in the black substantia and the formation of Lewy bodies, thus being considered a neurodegenerative disease. Thus, the objective was to understand the impact of polymorphisms in the predisposition to PD. Methods: It’s a narrative review of literature in the PubMed and SciELO databases, using the descriptors: “Polymorphism, Single Nucleotide” and “Parkinson disease”, registered in DeCS/MeSH, and using the Boolean operator AND. The inclusion criteria were: complete articles and made available free of charge, published in English, Spanish and Portuguese, between 2016 and January 2021. Results: After the research, 167 publications were found and seven were included. The data from the first study indicate that the rs33949390 of the LRRK2 gene helps in predisposition to PD in Asian populations, mainly Chinese. The second study indicated that the NFE2L2 rs6721961 allele was linked to a reduced risk of PD. The third study found that the GSK3B rs1732170, STK11 rs8111699, SNCA rs356219 and FCHSD1 rs456998 polymorphisms were linked to a high risk of PD. The fourth study found that the SNCA variants rs7684318, rs356220, rs356203 and rs2736990 were linked to the disease and were at high risk of developing PD in the Mexican population. The fifth and sixth study are meta-analyzes, the fifth confirming the lower allele rs11558538 of HNMT is associated with a reduced risk of developing PD. And the sixth assumes a possible link between CCDC62 rs12817488 and the risk of PD in the Chinese population. Conclusion: However, the analyzed data indicate that the polymorphisms contributed to the susceptibility to PD, however further studies related to the polymorphisms and their relationship to PD are still needed for more ethnic groups, and thus early diagnosis is possible.