Research progress on the association between Parkinson′s disease and inflammatory bowel disease in genetics and gut microbiota / 中华神经科杂志

Parkinson′s disease (PD) is a common degenerative disease of central nervous system. PD is closely related to gastrointestinal diseases in comorbidity studies, and the “gut brain axis” disorder may be involved in their relationship. In recent years, relevant studies have suggested that there are genetic and epidemiological evidences to link PD with inflammatory bowel disease (IBD). This article reviews the relationship between PD and IBD from the genetic evidence and the relevant concept of “gut brain axis”.

The therapeutic effect of quercetin on the transgenic PD drosophila model with LRRK2 mutation / 西安交通大学学报(医学版)

Objective: To study the therapeutic effect and mechanism of quercetin on Parkinson's disease (PD) model induced by a leucine-rich repeat kinase 2 (LRRK2) gene mutation. Methods: PD transgenic drosophila model Ddc-Gal4; UAS-LRRK2/G2019S was generated by Gal4/UAS hybridization and selectively expressed G2019S mutant LRRK2 in dopaminergic neurons. PD transgenic drosophila and control were fed with corn medium supplemented with quercetin in 1, 10 and 100 μmol/L for the treatment group, or with standard corn medium in PD model group and blank control group. The life span and locomotor ability were observed and compared between the quercetin treatment group and the PD drosophila model group. The brains of the drosophila were dissected and stained with TH immunofluorescence antibody to observe the survival rate of dopaminergic neurons. The brain tissues were also measured with Western blot to detect the protein expression levels of TH, GCLC, p-LRRK2, and p-p38MAPK. Results: The group treated with 10 μmol/L quercetin showed the best therapeutic effect on the prolongation of life span and improvement of locomotor ability compared with PD transgenic drosophila model without any treatment. The locomotor activity of drosophila was significantly improved at week 6 and the loss of dopaminergic neurons in the brain of the PD model drosophila was effectively diminished by quercetin. Quercetin also significantly lowered the level of phosphorylated LRRK2 in the PD transgenic drosophila compared with the PD model group (P<0.05), indicating the inhibiting effect of quercetin on the activity of LRRK2 kinase of the PD model. In addition, quercetin could activate the antioxidant-signaling pathway and inhibit the p38MAPK signaling pathway. Results: Quercetin can activate the antioxidant-signaling pathway and inhibit the LRRK2 kinase activity, which can further regulate MAPK signaling pathway and reduce the neurotoxicity of LRRK2 mutation and protect dopaminergic neurons in PD transgenic drosophila model.

LRRK2 Kinase Activity Induces Mitochondrial Fission in Microglia via Drp1 and Modulates Neuroinflammation

Leucine-rich repeat kinase 2 (LRRK2) mutations are the most common genetic cause of Parkinson's disease (PD). LRRK2 contains a functional kinase domain and G2019S, the most prevalent LRRK2 pathogenic mutation, increases its kinase activity. LRRK2 regulates mitochondria morphology and autophagy in neurons. LPS treatment increases LRRK2 protein level and mitochondrial fission in microglia, and down-regulation of LRRK2 expression or inhibition of its kinase activity attenuates microglia activation. Here, we evaluated the direct role of LRRK2 G2019S in mitochondrial dynamics in microglia. Initial observation of microglia in G2019S transgenic mice revealed a decrease in mitochondrial area and shortage of microglial processes compared with their littermates. Next, we elucidated the molecular mechanisms of these phenotypes. Treatment of BV2 cells and primary microglia with LPS enhanced mitochondrial fission and increased Drp1, a mitochondrial fission marker, as previously reported. Importantly, both phenotypes were rescued by treatment with GSK2578215A, a LRRK2 kinase inhibitor. Finally, the protein levels of CD68, an active microglia marker, Drp1 and TNF-α were significantly higher in brain lysates of G2019S transgenic mice compared with the levels in their littermates. Taken together, our data suggest that LRRK2 could promote microglial mitochondrial alteration via Drp1 in a kinase-dependent manner, resulting in stimulation of pro-inflammatory responses. This mechanism in microglia might be a potential target to develop PD therapy since neuroinflammation by active microglia is a major symptom of PD.

Intervention of Effective Parts of Acanthopanax Senticosus on the Expression of LRRK 2 in Injured PC12 Cells Induced by MPP+ / 中国药师

Objective:To observe the effects of effective parts of Acanthopanax senticosus on the expression of LRRK 2 in injured PC12 cells induced by MPP+ to explore the mechanism of neuroprotection of the effective parts of Acanthopanax senticosus.Methods:The PC12 cell model of Parkinson's disease (PD) was constructed by MPP+,and intervened by the effective parts of Acanthopanax senticosus.The cell survival rate was detected by MTT,the mRNA expression level of LRRK 2 was studied by PCR,and the protein expression of LRRK 2 was determined by immunohistochemistry and Western Blot.Results:Compared with that of the model group,the survival rate of the drug group increased with significant difference (P<0.01).Compared with those in the model group,the LRRK 2 gene and protein expression all decreased with significant differences (P<0.01).Conclusion:The effective parts of Acanthopanax senticosus show protective effects on the PC12 cell model of PD,and one of the mechanisms may be related with the decreased expression level of LRRK2 caused by the effective parts of Acanthopanax senticosus.

LRRK2 enhances Nod1/2-mediated inflammatory cytokine production by promoting Rip2 phosphorylation

The innate immune system is critical for clearing infection, and is tightly regulated to avert excessive tissue damage. Nod1/2-Rip2 signaling, which is essential for initiating the innate immune response to bacterial infection and ER stress, is subject to many regulatory mechanisms. In this study, we found that LRRK2, encoded by a gene implicated in Crohn's disease, leprosy and familial Parkinson's disease, modulates the strength of Nod1/2-Rip2 signaling by enhancing Rip2 phosphorylation. LRRK2 deficiency markedly reduces cytokine production in macrophages upon Nod2 activation by muramyl dipeptide (MDP), Nod1 activation by D-gamma-Glu-meso-diaminopimelic acid (iE-DAP) or ER stress. Our biochemical study shows that the presence of LRRK2 is necessary for optimal phosphorylation of Rip2 upon Nod2 activation. Therefore, this study reveals that LRRK2 is a new positive regulator of Rip2 and promotes inflammatory cytokine induction through the Nod1/2-Rip2 pathway.

LRRK2 Inhibits FAK Activity by Promoting FERM-mediated Autoinhibition of FAK and Recruiting the Tyrosine Phosphatase, SHP-2

Mutation of leucine-rich repeat kinase 2 (LRRK2) causes an autosomal dominant and late-onset familial Parkinson's disease (PD). Recently, we reported that LRRK2 directly binds to and phosphorylates the threonine 474 (T474)-containing Thr-X-Arg(Lys) (TXR) motif of focal adhesion kinase (FAK), thereby inhibiting the phosphorylation of FAK at tyrosine (Y) 397 residue (pY397-FAK), which is a marker of its activation. Mechanistically, however, it remained unclear how T474-FAK phosphorylation suppressed FAK activation. Here, we report that T474-FAK phosphorylation could inhibit FAK activation via at least two different mechanisms. First, T474 phosphorylation appears to induce a conformational change of FAK, enabling its N-terminal FERM domain to autoinhibit Y397 phosphorylation. This is supported by the observation that the levels of pY397-FAK were increased by deletion of the FERM domain and/or mutation of the FERM domain to prevent its interaction with the kinase domain of FAK. Second, pT474-FAK appears to recruit SHP-2, which is a phosphatase responsible for dephosphorylating pY397-FAK. We found that mutation of T474 into glutamate (T474E-FAK) to mimic phosphorylation induced more strong interaction with SHP-2 than WT-FAK, and that pharmacological inhibition of SHP-2 with NSC-87877 rescued the level of pY397 in HEK293T cells. These results collectively show that LRRK2 suppresses FAK activation through diverse mechanisms that include the promotion of autoinhibition and/or the recruitment of phosphatases, such as SHP-2.

Analysis of the LRRK2 p.G2019S mutation in Colombian Parkinson's Disease Patients / Análisis de la mutación p.G2019S del gen LRRK2 en pacientes colombianos con enfermedad de Parkinson

Introduction: Mutations in the leucine-rich repeat kinase 2 gene (LRRK2 or Dardarin) are considered to be a common cause of autosomal dominant and sporadic Parkinson's disease, but the prevalence of these mutations varies among populations. Objective: To analyzed the frequency of the LRRK2 p.G2019S mutation (c.6055G>A transition) in a sample of Colombian patients. Methods: In the present study we have analyzed the frequency of the LRRK2 p.G2019S mutation in 154 patients with familial or sporadic Parkinson Disease, including early and late onset patients, and 162 normal controls. Results: Our results show occurrence of this mutation in two cases (2/154, 1.3%) with classical Parkinson's signs, and one completely asymptomatic control (1/162, 0.6%). Conclusion: The p.G2019S mutation is not an important causal factor of Parkinson Disease in Colombia having similar frequencies to those reported in other Latin American populations.

Introducción: Las mutaciones en el LRRK2 (del inglés gen leucinerich repeat kinase 2) o Dardarina se consideran una causa común de enfermedad de Parkinson autosómica dominante. Sin embargo, la prevalencia de estas mutaciones varia en diferentes poblaciones. Objetivo: Snalizar la frecuencia de la mutación p.G2019S (transición c.6055 G>A) del gen LRRK2en una muestra de pacientes colombianos. Métodos: En el presente estudio analizamos la frecuencia de la mutación en 154 pacientes con enfermedad de Parkinson familiar o esporádica, y 162 controles normales. Resultados: Se determinó la presencia de la mutación en 2 casos de Parkinson (2/154, 1.3%) los cuales presentan los signos clásicos de la enfermedad y en un control completamente asintomático (1/162, 0.6%). Conclusión: La mutación p.G2019S no es un factor causal importante de la Enfermedad de Parkinson en la población Colombiana, y muestra frecuencias similares a las reportadas en otras poblaciones latinoamericanas.

Frequency of the LRRK2 G2019S mutation in late-onset sporadic patients with Parkinson’s disease / Frequência da mutação G2019S do LRRK2 em pacientes com doença de Parkinson esporádica e início tardio

Mutations in the LRRK2 gene, predominantly G2019S, have been reported in individuals with autosomal dominant inheritance and sporadic Parkinson’s disease (PD). The G2019S mutation has an age-dependent penetrance and evidence shows common ancestry. The clinical manifestations are indistinguishable from idiopathic PD. Its prevalence varies according to the population studied ranging from less than 0.1% in Asians to 41% in North African Arabs. This study aimed to identify G2019S mutation in Brazilian idiopathic PD patients. Method: We sampled 100 PD patients and 100 age- and gender-matched controls. Genetical analysis was accomplished by polymerase chain reaction (PCR). Results: No G2019S mutations were found in both patients with sporadic PD and controls. Conclusions: Our results may be explained by the relatively small sample size. .

Mutação no gene LRRK2, predominantemente G2019S, foi descrita em indivíduos com doença de Parkinson (DP) esporádica ou herança autossômica dominante. A penetrância da mutação varia com a idade e há evidências de ancestral comum. As manifestações clínicas são indistinguíveis da DP idiopática. Sua prevalência depende da população estudada e varia de 0,1% em asiáticos a 41% em árabes do norte africano. O objetivo desse estudo foi identificar a mutação G2019S em brasileiros com DP esporádica. Método: Foram testados 100 pacientes com DP e 100 controles pareados por idade e sexo. A análise genética foi realizada pela reação em cadeia por polimerização (PCR). Resultados: Não foi encontrada a mutação G2019S nem nos pacientes com DP nem nos controles. Conclusão: É possível que nossos resultados sejam devidos ao pequeno número de pacientes incluídos. .

ULK1 and JNK are involved in mitophagy incurred by LRRK2 G2019S expression

Mutations in LR RK2 (Leucine rich repeat kinase 2) are a major cause of Parkinson's disease (PD). We and others reported recently that expression of the pathogenic gainof-function mutant form of LRRK2, LRRK2 G2019S, induces mitochondrial fission in neurons through DLP1. Here we provide evidence that expression of LRRK2 G2019S stimulates mitochondria loss or mitophagy. We have characterized several LRRK2 interacting proteins and found that LRRK2 interacts with ULK1 which plays an essential role in autophagy. Knockdown of either ULK1 or DLP1 expression with shRNAs suppresses LRRK2 G2019S expression-induced mitochondrial clearance, suggesting that LRRK2 G2019S expression induces mitochondrial fission through DLP1 followed by mitophagy via an ULK1 dependent pathway. In addition to ULK1, we found that LRRK2 interacts with the endogenous MKK4/7, JIP3 and coordinates with them in the activation of JNK signaling. Interestingly, LRRK2 G2019S-induced loss of mitochondria can also be suppressed by 3 different JNK inhibitors, implying the involvement of the JNK pathway in the pathogenic mechanism of mutated LRRK2. Thus our findings may provide an insight into the complicated pathogenesis of PD as well as some clues to the development of novel therapeutic strategies.

LRRK2 phosphorylates Snapin and inhibits interaction of Snapin with SNAP-25

Leucine-rich repeat kinase 2 (LRRK2) is a gene that, upon mutation, causes autosomal-dominant familial Parkinson's disease (PD). Yeast two-hybrid screening revealed that Snapin, a SNAP-25 (synaptosomal-associated protein-25) interacting protein, interacts with LRRK2. An in vitro kinase assay exhibited that Snapin is phosphorylated by LRRK2. A glutathione-S-transferase (GST) pull-down assay showed that LRRK2 may interact with Snapin via its Ras-of-complex (ROC) and N-terminal domains, with no significant difference on interaction of Snapin with LRRK2 wild type (WT) or its pathogenic mutants. Further analysis by mutation study revealed that Threonine 117 of Snapin is one of the sites phosphorylated by LRRK2. Furthermore, a Snapin T117D phosphomimetic mutant decreased its interaction with SNAP-25 in the GST pull-down assay. SNAP-25 is a component of the SNARE (Soluble NSF Attachment protein REceptor) complex and is critical for the exocytosis of synaptic vesicles. Incubation of rat brain lysate with recombinant Snapin T117D, but not WT, protein caused decreased interaction of synaptotagmin with the SNARE complex based on a co-immunoprecipitation assay. We further found that LRRK2-dependent phosphorylation of Snapin in the hippocampal neurons resulted in a decrease in the number of readily releasable vesicles and the extent of exocytotic release. Combined, these data suggest that LRRK2 may regulate neurotransmitter release via control of Snapin function by inhibitory phosphorylation.

LRRK2 as a Potential Genetic Modifier of Synucleinopathies: Interlacing the Two Major Genetic Factors of Parkinson's Disease

Parkinson's disease (PD) and related Lewy body diseases are characterized by deposition of alpha-synuclein aggregates in both the central nervous system and peripheral nervous system. Synucleinopathy lesions spread to larger brain areas as the disease progresses, and prion-like cell-to-cell transmission of aggregated alpha-synuclein is thought to be the underlying mechanism for this pathological spreading. LRRK2 is another protein linked to the pathogenesis of PD, and its presence in Lewy bodies has attracted much attention as to whether LRRK2 and alpha-synuclein interplay during the pathogenesis of PD. However, the relationship between these two crucial proteins still remains unclear. In this review article, we will discuss the current state of knowledge in terms of how these proteins cause the disease and provide the hypothetical mechanisms by which LRRK2 might modify the generation and progression of synucleinopathy.

Relação entre a doença de Parkinson e o gene LRRK2: um estudo na população brasileira / Relationship between Parkinson's disease and gene LRRK2: a study in 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 de levodopa. As características patológicas da DP incluem a despigmentação da substãncia 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...

Parkinson's disease (PD) is the second most common neurodegenerative disease after Alzheimer's 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 altetations (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...

Coordinate Regulation of Neurite Outgrowth by LRRK2 and Its Interactor, Rab5

Neurite outgrowth and its maintenance are essential aspects of neuronal cells for their connectivity and communication with other neurons. Recent studies showed that over-expression of either leucine-rich repeat kinase 2 (LRRK2), whose mutations are associated with familial Parkinson's disease (PD), or Rab5b, an early endosomal marker protein, induces reduction in neurite length. Based on our recent findings that LRRK2 co-localizes and interacts with Rab5, we tested the hypothesis that LRRK2 and Rab5 may functionally interplay while controlling neurite outgrowth. Firstly, we confirmed previous reports that over-expression of either the LRRK2 PD-specific G2019S mutant or the Rab5 constitutively active Q79L mutant, but not of dominant negative N133I mutant, significantly reduces neurite outgrowth. Secondly, when over-expression of either LRRK2 wild type (WT) or G2019S was accompanied with over-expression of one of the Rab5 variants (WT, Q79L and N133I), or with down-regulation of Rab5, the reduction extent of its neurite length was similar to that of cells over-expressing LRRK2 alone, regardless of Rab5's status. Finally, we observed similar patterns of neurite length regulation in embryonic rat hippocampal neuron cultures. Taken together, our results suggest that LRRK2 and Rab5 functionally coordinate their regulation of neurite outgrowth and that LRRK2 is a more critical factor than Rab5.

The G2019S LRRK2 Mutation is Rare in Korean Patients with Parkinson's Disease and Multiple System Atrophy

BACKGROUND AND PURPOSE: The LRRK2 (PARK8; OMIM607060) substitution was recently identified as a causative mutation for Parkinson's disease (PD). The pathologic heterogeneity of LRRK2-positive patients suggests that mutation of the LRRK2 gene is associated with the pathogenesis of PD and Parkinson-plus disorders, such as multiple system atrophy (MSA). We previously reported that the G2019S LRRK2 mutation-which is the most common LRRK2 mutation-was not found in a sample of 453 Korean PD patients. In the present study, we extended the screening for the G2019S mutation to a larger group of PD and MSA patients. METHODS: We performed a genetic analysis of the G2019S mutation in 877 patients with PD and 199 patients with MSA using a standard PCR and restriction digestion method. RESULTS: None of the subjects carried the G2019S mutation. CONCLUSIONS: The results of the present study support that the G2019S mutation is extremely rare in PD and is unlikely to be associated with MSA in the Korean population.

Screening of LRRK2 interactants by yeast 2-hybrid analysis / 中南大学学报(医学版)

Objective To isolate and identify the potential binding partners of LRRK2,a gene linked to both dominant familial form and sporadic form of Parkinson's disease,thus to further our knowledge of its function.Methods We used a sequence containing full-length of COR domain and part of ROC and MAPKKK domain as bait.The bait amplified by polymerase chain reaction(PCR) was then cloned into a yeast expression plasmid pGBKT7.After being sequenced and analyzed,pGBKT7-bait was transformed into the yeast strain AH109.Western blot was performed to confirm the expression of pGBKT7-bait in AH109 yeast strain.Then human fetal brain cDNA library was trarnsformed into that yeast strain.which could express pGBKT7-bait fusion protein.The yeast strain which contained pGBKT7-bait and human fetal brain cDNA library was plated on quadruple dropout medium (SD/-Trp/-Leu/-His/-Ade)containing X-a-gal.We retested these positive colonies using 2 independent yeast strains AH109 contained pGBKT7-bait or pGBKT7,respectively.At last,these plasmids isolated from these true positive colonies were analyzed by bioinformatics.Results We obtained 9 true positive colonies,these colonies were sequenced, and we performed sequence Blast in GenBank.Three colonies of the 9 positive colonies were not in open reading-frames.Among other 6 colonies,there were known proteins including spermatid perinuclear RNA-binding protein(STRBP)and BCL2-associated athanogene 5 isoform b(BAG5),as well as unknown proteins including tyrosine phosphatase non-receptor type(PTPN23),1(3)mbt-like 3 isoform b(L3 MBTL3),RALY RNA binding protein-like isoform 1(RALYL),and Homo sapiens mRNA for KIAA1783 protein,partial cds(KIAA 1783).Conclusion True positive colonies of LRRK2 are successfully obtained by the yeast 2-hybrid.Our screened proteins may provide a new research clue for revealing biological functions of LRRK2,pathogenesis of Parkinson's disease,and other neurodegerations.