帕金森病致病基因LRRK2的研究进展

富含亮氨酸重复序列激酶2基因(1eucine-rich repeat kinase 2 gene,LRRK2)是家族性常染色体显性遗传性帕金森病8型的致病基因,其突变所致帕金森病具有与原发性帕金森病极为相似的临床表现,但神经病理改变却呈现出多样性.且突变类型、发生频率在不同人种间存在显著性差异.IRRK2在体内分布广泛,功能复杂,具有多个功能结构域,序列比对后推测,LRRK2可能作为一种对底物蛋白进行磷酸化修饰的多功能激酶或支架蛋白来发挥功能.对LRPK2正常生理功能及致病机制的研究,有助于深入探索帕金森病的发病机制以及寻求有效的防治措施.     

Parkin基因新的多态位点IVS3-20 T→C增加早发性帕金森病的发病风险

目的 确定parkin基因第3内含子区新的多态位点IVS3-20 T→C多态与帕金森病(Parkinson’s disease，PD)的相关性。尤其是该多态与PD发病年龄的关系。方法 经PCR扩增后。用变性高效液相色谱和DNA自动测序等方法分析了312例PD患者和236名正常对照parkin基因IVS3—20 T→C多态性位点分布频率的差异。结果 总体分析未发现C／C纯合型。PD组T／C基因型频率和C等位基因频率与对照组相比有明显升高，但差异无显著性。将PD组按年龄分层后。45岁以下PD患者IVS3—20 T→C多态T／C基因型频率(7．07%)明显高于正常对照组(2．12%)。OR=3．52，95%CI为0．97～13．13(P=0．0263)。C等位基因频率(3．90%)也明显高于正常对照组(1．06％)。OR=3．42。95%CI为0．96～12．57(P=0．0276)．而45岁以上PD组与正常对照组相比差异无显著性。年龄分层后的趋势分析显示parkin基因IVS3-20 T／C多态性相对危险度与PD发病年龄间存在负相关联系．结论 发现了parkin基因IVS3-20 T→C多态位点，并提示IVS3-20 T→C多态位点可能是中国人散发性早发PD的一个危险因素。     

Parkin基因启动子区-258T/G多态性与广西地区散发性帕金森病的相关性分析

目的 探讨广西地区parkin基因启动子区-258T/G多态性与散发性帕金森病(sporadicParkinson's disease,SPD)的相关性及该多态性与PD发病年龄的关系.方法 PCR-RFLP及DNA测序等技术,分析parkin基因-258T/G多态性在PD患者和健康对照者间分布频率的差异.结果 PD组parkin基因-258T/G多态性位点G等位基因频率显著高于正常对照组(55.20%:43.33%,x2=6.898,P<0.05,OR=1.61,95%CI:1.13～2.30);GG基因型频率显著高于对照组(28.00%:18.33%,x2=7.159,P<0.05,OR=2.75,95%CI:1.31-5.77).同时,TG+GG基因型频率亦显著高于对照组(82.40%:68.33%,x2=6.551,P<0.05,OR=2.17,95%CI:1.20～3.93).50岁及50岁以上发病患者G等位基因频率和GG基因型频率显著高于对照组,50岁以下发病患者各频率虽高于正常对照组但差异无统计学意义.结论 Parkin基因核心启动子区-258T/G多态G等位基因可能增加了广西地区PD发病风险,且与PD发病年龄成正相关.     

Parkin基因启动子区-258T/G多态性与广西地区散发性帕金森病的相关性分析

Objective To investigate the association between the-258T/G polymorphism.in the pro-moter of parkin gene and the risk for sporadic parkinson's disease (SPD) in Guangxi Province, and in relationto the age of onset, of PD patients. Methods PCR-RFLP and sequence analysis were used to determine thegenotype of-258T/G polymorphism between all patients and healthy controls. Results The G allele was morecommon in patients than controls (55.20%:43.33% ,x2=6.898, P<0.05, OR=1.61, 95% CI: 1.13 ～2.30). The frequency of GG genotype was higher in patients than in controls (28.00 %: 18.33%, x2=7.159, P<0.05, OR=2.75, 95% CI : 1.31 ～ 5.77). The frequency of TG + GG genotype was higher in pa-tients than in controls (82.40%:68.33%, x2=6.551, P<0.05, OR=2.17.95%CI: 1.20 ～3.93). Afterbeing stratified by onset age, the frequencies of the G allele and GG genotype were significantly higher in pa-tients with onset age over 50 years than those in controls respectively. On the other hand, the frequency was notsignificantly different between the younger onset PD patients and the controls. Conclusion The parkin promot-er-258T/G polymorphism might be a risk factor for PD in Guangxi Province, and the G allele was increasedwith increasing age.     

Parkin基因启动子区-258T/G多态性与广西地区散发性帕金森病的相关性分析

Objective To investigate the association between the-258T/G polymorphism.in the pro-moter of parkin gene and the risk for sporadic parkinson's disease (SPD) in Guangxi Province, and in relationto the age of onset, of PD patients. Methods PCR-RFLP and sequence analysis were used to determine thegenotype of-258T/G polymorphism between all patients and healthy controls. Results The G allele was morecommon in patients than controls (55.20%:43.33% ,x2=6.898, P<0.05, OR=1.61, 95% CI: 1.13 ～2.30). The frequency of GG genotype was higher in patients than in controls (28.00 %: 18.33%, x2=7.159, P<0.05, OR=2.75, 95% CI : 1.31 ～ 5.77). The frequency of TG + GG genotype was higher in pa-tients than in controls (82.40%:68.33%, x2=6.551, P<0.05, OR=2.17.95%CI: 1.20 ～3.93). Afterbeing stratified by onset age, the frequencies of the G allele and GG genotype were significantly higher in pa-tients with onset age over 50 years than those in controls respectively. On the other hand, the frequency was notsignificantly different between the younger onset PD patients and the controls. Conclusion The parkin promot-er-258T/G polymorphism might be a risk factor for PD in Guangxi Province, and the G allele was increasedwith increasing age.     

Parkin基因启动子区-258T/G多态性与广西地区散发性帕金森病的相关性分析

Objective To investigate the association between the-258T/G polymorphism.in the pro-moter of parkin gene and the risk for sporadic parkinson's disease (SPD) in Guangxi Province, and in relationto the age of onset, of PD patients. Methods PCR-RFLP and sequence analysis were used to determine thegenotype of-258T/G polymorphism between all patients and healthy controls. Results The G allele was morecommon in patients than controls (55.20%:43.33% ,x2=6.898, P<0.05, OR=1.61, 95% CI: 1.13 ～2.30). The frequency of GG genotype was higher in patients than in controls (28.00 %: 18.33%, x2=7.159, P<0.05, OR=2.75, 95% CI : 1.31 ～ 5.77). The frequency of TG + GG genotype was higher in pa-tients than in controls (82.40%:68.33%, x2=6.551, P<0.05, OR=2.17.95%CI: 1.20 ～3.93). Afterbeing stratified by onset age, the frequencies of the G allele and GG genotype were significantly higher in pa-tients with onset age over 50 years than those in controls respectively. On the other hand, the frequency was notsignificantly different between the younger onset PD patients and the controls. Conclusion The parkin promot-er-258T/G polymorphism might be a risk factor for PD in Guangxi Province, and the G allele was increasedwith increasing age.     

Parkin基因启动子区-258T/G多态性与广西地区散发性帕金森病的相关性分析

Objective To investigate the association between the-258T/G polymorphism.in the pro-moter of parkin gene and the risk for sporadic parkinson's disease (SPD) in Guangxi Province, and in relationto the age of onset, of PD patients. Methods PCR-RFLP and sequence analysis were used to determine thegenotype of-258T/G polymorphism between all patients and healthy controls. Results The G allele was morecommon in patients than controls (55.20%:43.33% ,x2=6.898, P<0.05, OR=1.61, 95% CI: 1.13 ～2.30). The frequency of GG genotype was higher in patients than in controls (28.00 %: 18.33%, x2=7.159, P<0.05, OR=2.75, 95% CI : 1.31 ～ 5.77). The frequency of TG + GG genotype was higher in pa-tients than in controls (82.40%:68.33%, x2=6.551, P<0.05, OR=2.17.95%CI: 1.20 ～3.93). Afterbeing stratified by onset age, the frequencies of the G allele and GG genotype were significantly higher in pa-tients with onset age over 50 years than those in controls respectively. On the other hand, the frequency was notsignificantly different between the younger onset PD patients and the controls. Conclusion The parkin promot-er-258T/G polymorphism might be a risk factor for PD in Guangxi Province, and the G allele was increasedwith increasing age.     

Parkin基因启动子区-258T/G多态性与广西地区散发性帕金森病的相关性分析

Objective To investigate the association between the-258T/G polymorphism.in the pro-moter of parkin gene and the risk for sporadic parkinson's disease (SPD) in Guangxi Province, and in relationto the age of onset, of PD patients. Methods PCR-RFLP and sequence analysis were used to determine thegenotype of-258T/G polymorphism between all patients and healthy controls. Results The G allele was morecommon in patients than controls (55.20%:43.33% ,x2=6.898, P<0.05, OR=1.61, 95% CI: 1.13 ～2.30). The frequency of GG genotype was higher in patients than in controls (28.00 %: 18.33%, x2=7.159, P<0.05, OR=2.75, 95% CI : 1.31 ～ 5.77). The frequency of TG + GG genotype was higher in pa-tients than in controls (82.40%:68.33%, x2=6.551, P<0.05, OR=2.17.95%CI: 1.20 ～3.93). Afterbeing stratified by onset age, the frequencies of the G allele and GG genotype were significantly higher in pa-tients with onset age over 50 years than those in controls respectively. On the other hand, the frequency was notsignificantly different between the younger onset PD patients and the controls. Conclusion The parkin promot-er-258T/G polymorphism might be a risk factor for PD in Guangxi Province, and the G allele was increasedwith increasing age.     

Parkin基因多态性与四川地区散发性帕金森病的相关性研究

目的了解四川地区散发性帕金森病parkin基因多态性与帕金森病(Parkinson’s disease,PD)的相关性。方法采用病例-对照研究,应用聚合酶链反应、限制性片段长度多态性、变性高效液相色谱及DNA测序等技术,对四川地区汉族人群198例帕金森病患者和187名正常对照parkin基因-258T/G及IVS3-20T/C多态性位点进行研究,并通过比较各多态性在PD患者和正常对照人群中的频率分布,探讨基因多态性与PD的可能关系。结果parkin基因-258T/G多态性PD组G等位基因频率明显高于对照组(52.5%vs43.3%),两组差异有统计学意义(χ2=6.17,P<0.025,OR=1.45,95%CI:1.04~1.86);进一步将PD组按发病年龄分层发现,只有50岁以上发病患者与对照组相比G等位基因频率差异具有统计学意义(χ2=9.048,P<0.01,OR=1.57,95%CI:1.08~2.06);同样,与对照组(69.51%)相比,PD组TG GG基因型频率(78.79%)亦增加,两者间差异具有统计学意义(χ2=3.854,P<0.05,OR=1.63,95%CI0.88~2.38);PD组不同基因型组间发病年龄差异具有统计学意义(P<0.05),GG基因型组的平均发病年龄比TT或TG基因型的发病晚近5年左右。parkin基因IVS3-20T/C多态性以CC基因型多见,TC型杂合子的频率较低,该实验未发现TT基因型。结论核心启动子区-258T/G多态G等位基因可能增加了四川地区汉族人群散发性PD发生的风险,尤其是50岁以后的发病风险;四川地区汉族人群IVS3-20T/C位点,以CC基因型多见,TC型杂合子的频率较低,无TT基因型。     

Parkin基因启动子区-258T/G多态性与广西地区散发性帕金森病的相关性分析

Objective To investigate the association between the-258T/G polymorphism.in the pro-moter of parkin gene and the risk for sporadic parkinson's disease (SPD) in Guangxi Province, and in relationto the age of onset, of PD patients. Methods PCR-RFLP and sequence analysis were used to determine thegenotype of-258T/G polymorphism between all patients and healthy controls. Results The G allele was morecommon in patients than controls (55.20%:43.33% ,x2=6.898, P<0.05, OR=1.61, 95% CI: 1.13 ～2.30). The frequency of GG genotype was higher in patients than in controls (28.00 %: 18.33%, x2=7.159, P<0.05, OR=2.75, 95% CI : 1.31 ～ 5.77). The frequency of TG + GG genotype was higher in pa-tients than in controls (82.40%:68.33%, x2=6.551, P<0.05, OR=2.17.95%CI: 1.20 ～3.93). Afterbeing stratified by onset age, the frequencies of the G allele and GG genotype were significantly higher in pa-tients with onset age over 50 years than those in controls respectively. On the other hand, the frequency was notsignificantly different between the younger onset PD patients and the controls. Conclusion The parkin promot-er-258T/G polymorphism might be a risk factor for PD in Guangxi Province, and the G allele was increasedwith increasing age.     

Inhibitory role of peroxiredoxin 2 in LRRK2 kinase activity induced cellular pathogenesis

Parkinson's disease (PD) is a major neurodegenerative disease. One of the known genetic contributors to PD pathogenesis is leucine-rich repeat kinase 2 (LRRK2) whose mutations with elevated kinase activity could lead to both familial and sporadic PD. However, how the pathogenic kinase activity of LRRK2 is regulated remains largely unclear. Here we report that peroxiredoxin 2 (Prx2) was identified as a novel interacting protein to LRRK2 with preferential expression in dopaminergic neurons over other Prx proteins. We also confirmed that Prx2 interacted with LRRK2 through its COR domain and its overexpression significantly decreased the kinase activity of mutant LRRK2. Functionally, overexpressed Prx2 rescued the transfected cells from LRRK2 mutant induced apoptotic processes. Importantly, overexpressed Prx2 reversed the altered subcellular distribution of cation-independent mannose 6-phosphate receptor (CI-M6PR) induced by PD-mutant LRRK2. Our results suggest that, by interacting with LRRK2, Prx2 may play an inhibitory role in the LRRK2 mediated cellular toxicity in PD by inhibiting its kinase activity.     

LRRK2 gene variation and its contribution to Parkinson disease

Mutation in the LRRK2 gene is a known genetic cause of Parkinson disease (PD). However, due to the high frequency in which the most frequent LRRK2 mutation is present and the large size of LRRK2 gene, a complete sequence‐based screening of the entire coding region has only been performed by a few researchers. In addition, normal variability in the LRRK2 gene has only been fully assessed in the North American population. Although a complete examination of the entire gene is required to assess the exact contribution of LRRK2 to the etiology of PD, more than 50 variants have been reported to date within the LRRK2 locus. Gene multiplications or deletions have not been reported so far. Here, all LRRK2 variants reported are interpreted and their contribution to the disease is examined. Hum Mutat 30,1–8, 2009. © 2009 Wiley‐Liss, Inc.     

LRRK2 variant associated with Alzheimer's disease

Overlapping neurodegenerative pathologies (including Alzheimer's disease, AD) have been described in Parkinson's disease (PD) patients with leucine-rich repeat kinase-2 (LRRK2) mutations. We analyzed a LRRK2 PD (R1628P) risk variant in a group of 885 subjects comprising of AD and controls. The frequency of the R1628P allele was higher in AD compared to controls (3.5% vs. 1.6%, OR 2.3, 95 CI 1.2-4.4, p = 0.018). In vitro, the mean percentage of apoptosis and cell death observed for the R1628P transfected human cell lines was higher compared to wild type 21.8 ± 1.9, vs. 17.1 ± 1.3, p < 0.05, 30.2 ± 2.2 vs. 25.7 ± 1.3, p < 0.05). The LRRK2 R1628P variant increases the risk of AD in our population and our in vitro findings suggest that it is a functional variant and predisposes to apoptosis.     

Parkinson's Disease and Low Frequency Alleles Found Together Throughout LRRK2

Mutations within LRRK2 , most notably p.G2019S , cause Parkinson's disease (PD) in rare monogenic families, and sporadic occurrences in diverse populations. We investigated variation throughout LRRK2 (84 SNPs; genotype or diplotype found for 49 LD blocks) for 275 cases (European ancestry, onset at age 60 or older) and 275 neurologically healthy control subjects (NINDS Neurogenetics Repository). Three grade-of-membership groups, i.e. genetic risk sets, were identified that exactly matched many subjects (cases: 46, 4, 137; controls: 0, 178, 0), and distinguished 94% of the subjects (i.e. >50% likeness to one set). Set I, affected, carried certain low frequency alleles located in multiple functional domains. Set II was unaffected. Set III, also affected, resembled set II except for slightly elevated frequencies of minor alleles not defining set I. We conclude that certain low frequency alleles distributed throughout LRRK2 are a genetic background to a third of cases, defining a distinct subset.     

Curcumin exposure induces expression of the Parkinson's disease-associated leucine-rich repeat kinase 2 (LRRK2) in rat mesencephalic cells

Turmeric (curry powder), an essential ingredient of culinary preparations of Southeast Asia, contains a major polyphenolic compound known as curcumin or diferuloylmethane. Curcumin is a widely studied phytochemical with a variety of biological activities. In addition to its anti-inflammatory and antimicrobial/antiviral properties, curcumin is considered as a cancer chemopreventive agent as well as a modulator of gene expression and a potent antioxidant. Since oxidative stress has been implicated in the degeneration of dopaminergic neurons in the substantia nigra in Parkinson's disease (PD), curcumin has been proposed to have potential therapeutic value for the treatment of neurodegenerative diseases such as PD. Following age, a family history of PD is the most commonly reported risk factor, suggesting a genetic component of the disease in a subgroup of patients. The LRRK2 gene has emerged as the gene most commonly associated with both familial and sporadic PD. Here, we report that exposure of rat mesencephalic cells to curcumin induces the expression of LRRK2 mRNA and protein in a time-dependent manner. The expression of other PD-related genes, such α-synuclein and parkin, was not affected by exposure to curcumin, and PTEN-induced putative kinase 1 (PINK1) was not expressed in rat mesencephalic cells. As LRRK2 overexpression is strongly associated with the pathological inclusions found in several neurodegenerative disorders, further studies are needed to evaluate the effects of curcumin as a therapeutic agent for neurodegenerative diseases.     

Distinctive roles of Rac1 and Rab29 in LRRK2 mediated membrane trafficking and neurite outgrowth

Parkinson's disease (PD) associated leucine-rich repeat kinase 2 (LRRK2) mutants have shown pathogenic effects on a variety of subcellular processes. Two small GTPases Rac1 and Rab29 have been indicated as possible downstream effectors participating in LRRK2 signaling but their detail mechanisms remain unclear. In this study, we have used biochemical and cell biology approaches to address whether two GTPases interact with LRRK2 and hence function differently in LRRK2 mediated pathogenesis. Here we show that Rac1 and Rab29 specifically interact with LRRK2 with higher affinity for Rab29 and with different preference in functional domain binding. Mutant Rab29 but not Rac1 alters the endosome-to-TGN retrograde trafficking of a cargo protein cation-independent mannose-6- phosphate receptor (CI-M6PR) and its stability. On the other hand, overexpressed wild type Rab29 but not Rac1 rescued the altered retrograde membrane trafficking induced by the pathogenic mutant LRRK2G2019S. Furthermore, both Rac1 and Rab29 rescued neurite shortening in differentiated SH-SY5Y cells induced by LRRK2G2019S. Our study strongly suggests that Rac1 and Rab29 are involved in distinct functions as downstream effectors in LRRK2 signaling pathways.     

Absence/rarity of commonly reported LRRK2 mutations in Indian Parkinson's disease patients

Recent discovery of pathogenic mutations in the leucine-rich repeat kinase 2 (LRRK2) gene in Parkinson's disease (PD) patients in different ethnic groups have raised a hope of diagnostic screening and genetic counseling. We investigated the six most commonly reported mutations in LRRK2 gene among Indian PD patients, using PCR-RFLP method. Mutations G2019S, R1441C, R1441G, and R1441H were screened in 1012 individuals (PD, 800; controls, 212) while mutations I2012T and I2020T were screened in 748 PD patients. We did not observe any of these six mutations in this study sample except in a single female young onset PD patient who showed a heterozygous G2019S mutation. The absence of mutations was reconfirmed by sequencing of probands from several autosomal dominant PD families. Our observations suggest that these mutations may be a rare cause of PD among Indians and therefore of little help for diagnostic screening and genetic counseling for Indian PD patients.