Association of rare PPARGC1A variants with Parkinson's disease risk.

BACKGROUND: Recent researches on Parkinson's disease (PD) pathogenesis discovered the correlation between PD and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) dysfunction and reduction of PPARGC1A gene expression. Hence, we detected PPARGC1A rare variants to clarify their effect on PD risk in a large population of PD patients in mainland China. METHODS: We applied whole-exome sequencing (WES) to 1917 patients with early-onset or familial PD and 1652 controls (WES cohort), and whole-genome sequencing (WGS) to 1962 patients with sporadic late-onset PD and 1279 controls (WGS cohort). To identify PPARGC1A rare variants, we used burden analysis to assess the relationship between PPARGC1A rare variants and PD susceptibility. RESULTS: 30 rare missense variants in the cohort WES and 21 missense variants in the cohort WGS have been detected in the study and PPARGC1A missense variants are significantly associated with early-onset and familial PD susceptibility in our study (P = 0.012), which supports evidence that PPARGC1A rare variants are involved in the onset of early-onset and familial PD. CONCLUSIONS: The study suggested that PPARGC1A rare variants may contribute to the risk of early-onset and familial PD.

PSEN1 G417S mutation in a Chinese pedigree causing early-onset parkinsonism with cognitive impairment.

Presenilin 1 (PSEN1) mutations are a major cause of familial Alzheimer's disease. The pathogenic variant, PSEN1 p.G417S, has been reported to be associated with spastic paraparesis and cotton wool plaques in Japan. Here, we report a 3 generation Chinese pedigree that included 10 patients presenting with early-onset and rapid progression of parkinsonism with cognitive impairment in their third or fourth decade of life. Three additional living patients developed different degrees of cognitive impairment, without movement disorders. Magnetic resonance imaging of the brain showed white matter hyperintensities, multiple microbleeds, and enlarged perivascular spaces. Whole exome sequencing analysis of the proband detected the mutation, p.G417S, in PSEN1, which was completely co-segregated with the disease phenotype within the family by Sanger sequencing. 3D protein structures predicted that the mutation might influence contact with the lipid membrane and the interaction with beta-catenin. Our study provides insights into the heterogeneity in clinical presentation and imaging associated with mutations in PSEN1.

Theranostic F-SLOH mitigates Alzheimer's disease pathology involving TFEB and ameliorates cognitive functions in Alzheimer's disease models.

Accumulation of amyloid-ß (Aß) oligomers and phosphorylated Tau aggregates are crucial pathological events or factors that cause progressive neuronal loss, and cognitive impairments in Alzheimer's disease (AD). Current medications for AD have failed to halt, much less reverse this neurodegenerative disorder; therefore, there is an urgent need for the development of effective and safe drugs for AD therapy. In the present study, the in vivo therapeutic efficacy of an Aß-oligomer-targeted fluorescent probe, F-SLOH, was extensively investigated in 5XFAD and 3XTg-AD mouse models. We have shown that F-SLOH exhibits an efficient inhibitory activity against Aß aggregation in vivo, and acts as an effective theranostic agent for the treatment of multiple neuropathological changes in AD mouse models. F-SLOH has been found to significantly reduce not only the levels of Aß oligomers, Tau aggregates and plaques but also the levels of amyloid precursor protein (APP) and its metabolites via autophagy lysosomal degradation pathway (ALP) in the brains of 5XFAD and 3XTg-AD mice. It also reduces astrocyte activation and microgliosis ultimately alleviating neuro-inflammation. Furthermore, F-SLOH mitigates hyperphosphorylated Tau aggregates, synaptic deficits and ameliorates synaptic memory function, and cognitive impairment in AD mouse models. The mechanistic studies have shown that F-SLOH promotes the clearance of C-terminal fragment 15 (CTF15) of APP and Paired helical filaments of Tau (PHF1) in stable cell models via the activation of transcription factor EB (TFEB). Moreover, F-SLOH promotes ALP and lysosomal biogenesis for the clearance of soluble, insoluble Aß, and phospho Tau. Our results unambiguously reveal effective etiological capabilities of theranostic F-SLOH to target and intervene multiple neuropathological changes in AD mouse models. Therefore, F-SLOH demonstrates tremendous therapeutic potential for treating AD in its early stage.

Corynoxine B derivative CB6 prevents Parkinsonian toxicity in mice by inducing PIK3C3 complex-dependent autophagy.

Increasing evidence shows that autophagy impairment is involved in the pathogenesis and progression of neurodegenerative diseases including Parkinson's disease (PD). We previously identified a natural alkaloid named corynoxine B (Cory B) as a neuronal autophagy inducer. However, its brain permeability is relatively low, which hinders its potential use in treating PD. Thus we synthesized various derivatives of Cory B to find more potent autophagy inducers with improved brain bioavailability. In this study, we evaluated the autophagy-enhancing effect of CB6 derivative and its neuroprotective action against PD in vitro and in vivo. We showed that CB6 (5-40 µM) dose-dependently accelerated autophagy flux in cultured N2a neural cells through activating the PIK3C3 complex and promoting PI3P production. In MPP+-treated PC12 cells, CB6 inhibited cell apoptosis and increased cell viability by inducing autophagy. In MPTP-induced mouse model of PD, oral administration of CB6 (10, 20 mg· kg-1· d-1, for 21 days) significantly improved motor dysfunction and prevented the loss of dopaminergic neurons in the striatum and substantia nigra pars compacta. Collectively, compound CB6 is a brain-permeable autophagy enhancer via PIK3C3 complex activation, which may help the prevention or treatment of PD.

TFEB, a master regulator of autophagy and biogenesis, unexpectedly promotes apoptosis in response to the cyclopentenone prostaglandin 15d-PGJ2.

Transcriptional factor EB (TFEB), a master regulator of autophagy and lysosomal biogenesis, is generally regarded as a pro-survival factor. Here, we identify that besides its effect on autophagy induction, TFEB exerts a pro-apoptotic effect in response to the cyclopentenone prostaglandin 15-deoxy-∆-12,14-prostaglandin J2 (15d-PGJ2). Specifically, 15d-PGJ2 promotes TFEB translocation from the cytoplasm into the nucleus to induce autophagy and lysosome biogenesis via reactive oxygen species (ROS) production rather than mTORC1 inactivation. Surprisingly, TFEB promotes rather than inhibits apoptosis in response to 15d-PGJ2. Mechanistically, ROS-mediated TFEB translocation into the nucleus transcriptionally upregulates the expression of ATF4, which is required for apoptosis elicited by 15d-PGJ2. Additionally, inhibition of TFEB activation by ROS scavenger N-acetyl cysteine or inhibition of protein synthesis by cycloheximide effectively compromises ATF4 upregulation and apoptosis in response to 15d-PGJ2. Collectively, these results indicate that ROS-induced TFEB activation exerts a novel role in promoting apoptosis besides its role in regulating autophagy in response to 15d-PGJ2. This work not only evidences how TFEB is activated by 15d-PGJ2, but also unveils a previously unexplored role of ROS-dependent activation of TFEB in modulating cell apoptosis in response to 15d-PGJ2.

Evaluating the role of ARSA in Chinese patients with Parkinson's disease.

Recent studies have suggested ARSA, a gene responsible for metachromatic leukodystrophy, could be a genetic modifier of Parkinson's disease (PD) pathogenesis, acting as a molecular chaperone for α-synuclein. To elucidate the role of ARSA variants in PD, we did a comprehensive analysis of ARSA variants by performing next-generation sequencing on 477 PD families, 1440 sporadic early-onset PD patients and 1962 sporadic late-onset PD patients and 2636 controls from Chinese mainland, as well as the association between ARSA variants and cognitive function of PD patients. We identified 2 familial PD following autosomal dominant inherence carrying rare variants of ARSA, but they had limited clinical significance. We detected a total of 81 coding variants of ARSA in our subjects but none of the identified variants were associated with either susceptibility or cognitive performance of PD, while loss-of-function variants showed slightly increased burden in late-onset PD (0.25% vs. 0%, p = 0.08). Our results suggested ARSA may not play important roles in PD of Chinese population.

Protopine promotes the proteasomal degradation of pathological tau in Alzheimer's disease models via HDAC6 inhibition.

BACKGROUND: Collective evidences have indicated that intracellular accumulation of hyperphosphorylated tau forms neurofibrillary tangles in the brain, which impairs memory, cognition and affects social activities in Alzheimer's disease (AD). PURPOSE: To investigate the tau-reducing, and memory-enhancing properties of protopine (PRO), a natural alkaloid isolated from Chinese herbal medicine Corydalis yanhusuo (Yanhusuo in Chinese). STUDY DESIGN: By using Histone deacetylase 6 (HDAC6) profiling and immunoprecipitation assays, we assessed that PRO mediated the heat shock protein 90 (HSP90) chaperonic activities for the degradation of pathological tau in AD cell culture models. To study the efficacy of PRO in vivo, we employed 3xTg-AD and P301S tau mice models. METHODS: Liquid chromatography/quadrupole time-of-flight mass spectrometry was used to analyze the pharmacokinetic profile of PRO. Seven-month-old 3xTg-AD mice and 1.5-month-old P301S mice were administered PRO (1 and 2.5 mg/kg) orally every day. Morris water maze, contextual fear conditioning and rotarod assays were applied for studying memory functions. Sarkosyl differential centrifugation was used to analyze soluble and insoluble tau. Immunohistochemical analysis were performed to determine tau deposits in AD mice's brain sections. Molecular docking, binding affinity studies and primary cell culture studies were performed to demonstrate the mechanism of action of PRO in silico and in vitro. RESULTS: Our pharmacokinetic profiling demonstrated that PRO significantly entered the brain at a concentration of 289.47 ng/g, and specifically attenuated tau pathology, improved learning and memory functions in both 3xTg-AD and P301S mice. Docking, binding affinity studies, and fluorometric assays demonstrated that PRO directly bound to the catalytic domain 1 (CD1) of HDAC6 and down-regulated its activity. In primary cortical neurons, PRO enhanced acetylation of α-tubulin, indicating HDAC6 inhibition. Meanwhile, PRO promoted the ubiquitination of tau and recruited heat shock protein 70 (HSP70) and heat shock cognate complex 71 (HSC70) for the degradation of pathological tau via the ubiquitin-proteasomal system (UPS). CONCLUSION: We identified PRO as a natural HDAC6 inhibitor that attenuated tau pathology and improved memory dysfunctions in AD mice. The findings from this study provides a strong justification for future clinical development of plant-derived protopine as a novel agent for the treatment of tau-related neurodegenerative diseases.

Low-frequency and rare coding variants of NUS1 contribute to susceptibility and phenotype of Parkinson's disease.

NUS1 has been recently identified as a candidate gene for Parkinson's disease (PD). Few studies have examined the association of NUS1 variants with PD susceptibility and phenotypes. In the first cohort, whole-exome sequencing was performed to identify variants in NUS1 exon-coding and exon-intron regions in 1542 cases and 1625 controls. 13 variants were totally detected, of which 10 rare variants and 3 low-frequency variants. Burden analysis showed that rare NUS1 variants significantly enriched in PD (p=0.016). We also performed a meta-analysis based on previous and our studies to correlate NUS1 mutations with PD susceptibility. Integrating our previous cohort (3210 cases and 2807 controls) and the first cohort identified the significant association of rs539668656 with PD risk (odds ratio (OR) = 2.82, p = 0.016). The genotype-phenotype association analysis showed that patients carrying rare variants, or rs539668656 were significantly associated with earlier onset age, depression, emotional impairment and severe disease condition. Our results support the role of NUS1 rare variants and rs539668656 towards PD susceptibility and phenotype.

The Association Between Lysosomal Storage Disorder Genes and Parkinson's Disease: A Large Cohort Study in Chinese Mainland Population.

Background: Recent years have witnessed an increasing number of studies indicating an essential role of the lysosomal dysfunction in Parkinson's disease (PD) at the genetic, biochemical, and cellular pathway levels. In this study, we investigated the association between rare variants in lysosomal storage disorder (LSD) genes and Chinese mainland PD. Methods: We explored the association between rare variants of 69 LSD genes and PD in 3,879 patients and 2,931 controls from Parkinson's Disease & Movement Disorders Multicenter Database and Collaborative Network in China (PD-MDCNC) using next-generation sequencing, which were analyzed by using the optimized sequence kernel association test. Results: We identified the significant burden of rare putative LSD gene variants in Chinese mainland patients with PD. This association was robust in familial or sporadic early-onset patients after excluding the GBA variants but not in sporadic late-onset patients. The burden analysis of variant sets in genes of LSD subgroups revealed a suggestive significant association between variant sets in genes of sphingolipidosis deficiency disorders and familial or sporadic early-onset patients. In contrast, variant sets in genes of sphingolipidoses, mucopolysaccharidoses, and post-translational modification defect disorders were suggestively associated with sporadic late-onset patients. Then, SMPD1 and other four novel genes (i.e., GUSB, CLN6, PPT1, and SCARB2) were suggestively associated with sporadic early-onset or familial patients, whereas GALNS and NAGA were suggestively associated with late-onset patients. Conclusion: Our findings supported the association between LSD genes and PD and revealed several novel risk genes in Chinese mainland patients with PD, which confirmed the importance of lysosomal mechanisms in PD pathogenesis. Moreover, we identified the genetic heterogeneity in early-onset and late-onset of patients with PD, which may provide valuable suggestions for the treatment.

Lycorine, a natural alkaloid, promotes the degradation of alpha-synuclein via PKA-mediated UPS activation in transgenic Parkinson's disease models.

BACKGROUND: Parkinson's disease (PD) is one of the most common neurodegenerative motor disorders, and is characterized by the presence of Lewy bodies containing misfolded α-synuclein (α-syn) and by selective degeneration of midbrain dopamine neurons. Studies have shown that upregulation of ubiquitin-proteasome system (UPS) activity promotes the clearance of aggregation-prone proteins such as α-syn and Tau, so as to alleviate the neuropathology of neurodegenerative diseases. PURPOSE: To identify and investigate lycorine as a UPS enhancer able to decrease α-syn in transgenic PD models. METHODS: Dot blot was used to screen α-syn-lowering compounds in an inducible α-syn overexpression cell model. Inducible wild-type (WT) and mutant α-syn-overexpressing PC12 cells, WT α-syn-overexpressing N2a cells and primary cultured neurons from A53T transgenic mice were used to evaluate the effects of lycorine on α-syn degradation in vitro. Heterozygous A53T transgenic mice were used to evaluate the effects of lycorine on α-syn degradation in vivo. mCherry-GFP-LC3 reporter was used to detect autophagy-dependent degradation. Ub-R-GFP and Ub-G76V-GFP reporters were used to detect UPS-dependent degradation. Proteasome activity was detected by fluorogenic substrate Suc-Leu-Leu-Val-Tyr-AMC (Suc-LLVY-AMC). RESULTS: Lycorine significantly promoted clearance of over-expressed WT and mutant α-syn in neuronal cell lines and primary cultured neurons. More importantly, 15 days' intraperitoneal administration of lycorine effectively promoted the degradation of α-syn in the brains of A53T transgenic mice. Mechanistically, lycorine accelerated α-syn degradation by activating cAMP-dependent protein kinase (PKA) to promote proteasome activity. CONCLUSION: Lycorine is a novel α-syn-lowering compound that works through PKA-mediated UPS activation. This ability to lower α-syn implies that lycorine has the potential to be developed as a pharmaceutical for the treatment of neurodegenerative diseases, such as PD, associated with UPS impairment and protein aggregations.

Preliminary Study of hsa-mir-626 Change in the Cerebrospinal Fluid in Parkinson's Disease.

CONTEXT: A host of microRNAs have been reported to suppress tumor growth, invasion, and metastasis and play roles in neurodegeneration disorders. Moreover, microRNA changes are found in the peripheral blood, cerebrospinal fluid (CSF), and brain tissues of central nervous system diseases, including glioma, Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis, and depression. Compared with other body fluids, CSF can reflect the brain pathological processes more accurately. AIMS: To understand whether microRNA expression may be misregulated in patients with PD, and further discover potential diagnostic biomarkers and promising therapeutic targets for PD. MATERIALS AND METHODS: Here, through real-time reverse-transcription polymerase chain reaction (RT-PCR), we compared CSF microRNA from 15 PD patients, 11 AD patients, and 16 controls with other neurologic disorders, such as encephalitis and Guillain-Barre syndrome. RESULTS: Finally, we identified hsa-miR-626 changes in the CSF of PD patients. The mean expression level of hsa-miR-626 was significantly reduced in the CSF of PD patients compared with AD patients and controls. CONCLUSIONS: Our approach provides a preliminary research for identifying biomarkers in the CSF that could be used for the detection, diagnosis, and monitoring of PD.

Contribution of coding/non-coding variants in NUS1 to late-onset sporadic Parkinson's disease.

INTRODUCTION: A recent study reported that rare variants in NUS1 were associated with Parkinson's disease (PD). We aimed to assess the relative contribution of rare and common coding/non-coding variants of NUS1 to late-onset PD patients (LOPD). METHODS: Whole genome sequencing data were analyzed for target NUS1 regions, derived from a cohort of 1962 cases and 1279 controls. The genetic association analyses were performed using logistic regression analysis and Sequence Kernel association test. Expression quantitative trait loci (eQTL) analysis was conducted to further explore the association of variants with NUS1 expression based on the data from GTEx database. RESULTS: We identified 18 rare coding variants. p.Y131C was first identified in LOPD. However, no significant burden of rare NUS1 coding variants in LOPD was found. The rare variant sets of two regulatory elements (GH06J117605 and GH06J117674) were significantly enriched in LOPD even after Bonferroni correction (adjusted P = 0.013; adjusted P = 0.010). Considering the joint effect of rare and common variants, all variant sets within GH06J117605 and GH06J117674 showed association with LOPD but were no longer significant after Bonferroni correction. None of the common variants within coding/non-coding regions were significant after Bonferroni correction. The eQTL results suggested these variants in GH06J117605 and GH06J117674 could potentially have eQTL effects on the brain tissues. CONCLUSIONS: These findings provide novel insight into the role of NUS1 regulatory regions in the development of LOPD and indicate that the variants in regulatory elements of NUS1 may be associated with LOPD by influencing the gene expression level.

NRBF2 is a RAB7 effector required for autophagosome maturation and mediates the association of APP-CTFs with active form of RAB7 for degradation.

NRBF2 is a component of the class III phosphatidylinositol 3-kinase (PtdIns3K) complex. Our previous study has revealed its role in regulating ATG14-associated PtdIns3K activity for autophagosome initiation. In this study, we revealed an unknown mechanism by which NRBF2 modulates autophagosome maturation and APP-C-terminal fragment (CTF) degradation. Our data showed that NRBF2 localized at autolysosomes, and loss of NRBF2 impaired autophagosome maturation. Mechanistically, NRBF2 colocalizes with RAB7 and is required for generation of GTP-bound RAB7 by interacting with RAB7 GEF CCZ1-MON1A and maintaining the GEF activity. Specifically, NRBF2 regulates CCZ1-MON1A interaction with PI3KC3/VPS34 and CCZ1-associated PI3KC3 kinase activity, which are required for CCZ1-MON1A GEF activity. Finally, we showed that NRBF2 is involved in APP-CTF degradation and amyloid beta peptide production by maintaining the interaction between APP and the CCZ1-MON1A-RAB7 module to facilitate the maturation of APP-containing vesicles. Overall, our study revealed a pivotal role of NRBF2 as a new RAB7 effector in modulating autophagosome maturation, providing insight into the molecular mechanism of NRBF2-PtdIns3K in regulating RAB7 activity for macroautophagy/autophagy maturation and Alzheimer disease-associated protein degradation..Abbreviations: 3xTg AD, triple transgenic mouse for Alzheimer disease; Aß, amyloid beta peptide; Aß1-40, amyloid beta peptide 1-40; Aß1-42, amyloid beta peptide 1-42; AD, Alzheimer disease; APP, amyloid beta precursor protein; APP-CTFs, APP C-terminal fragments; ATG, autophagy related; ATG5, autophagy related 5; ATG7, autophagy related 7; ATG14, autophagy related 14; CCD, coiled-coil domain; CCZ1, CCZ1 homolog, vacuolar protein trafficking and biogenesis associated; CHX, cycloheximide; CQ, chloroquine; DAPI, 4',6-diamidino-2-phenylindole; dCCD, delete CCD; dMIT, delete MIT; FYCO1, FYVE and coiled-coil domain autophagy adaptor 1; FYVE, Fab1, YGL023, Vps27, and EEA1; GAP, GTPase-activating protein; GDP, guanine diphosphate; GEF, guanine nucleotide exchange factor; GTP, guanine triphosphate; GTPase, guanosine triphosphatase; HOPS, homotypic fusion and vacuole protein sorting; ILVs, endosomal intralumenal vesicles; KD, knockdown; KO, knockout; LAMP1, lysosomal associated membrane protein 1; MAP1LC3/LC3, microtubule associated protein 1 light chain 3; MLVs, multilamellar vesicles; MON1A, MON1 homolog A, secretory trafficking associated; NRBF2, nuclear receptor binding factor 2; PtdIns3K, class III phosphatidylinositol 3-kinase; PtdIns3P, phosphatidylinositol-3-phosphate; RILP, Rab interacting lysosomal protein; SNARE, soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SQSTM1/p62, sequestosome 1; UVRAG, UV radiation resistance associated; VPS, vacuolar protein sorting; WT, wild type.

Assessment of the association between NUS1 variants and essential tremor.

BACKGROUND: A recent study on early onset Parkinson's disease (PD) revealed that NUS1 is a risk gene for PD. Clinically, essential tremor (ET) is closely related to PD. In this study, we aimed to detect NUS1 variants and assess the effect of those variants on patients with ET. METHODS: The 5 coding regions and the exon-intron boundaries of NUS1 were directly sequenced in 395 patients with ET and an equal number of healthy controls, matched for age and sex. The function of variants was assessed by pathogenic predictive software programs. Genetic analysis of variants was used to evaluate susceptibility to ET. RESULTS: A total of 6 exonic variants were identified, including 3 synonymous and 3 missense variants. The non-synonymous variants were predicted to be tolerable. No variants had significant association with ET (none of the p-values were less than 0.05, using Fisher's exact test). CONCLUSION: Our study suggested that NUS1 variants may not contribute to the risk of ET.

GCH1 variants contribute to the risk and earlier age-at-onset of Parkinson's disease: a two-cohort case-control study.

BACKGROUND: Common and rare variants of guanosine triphosphate cyclohydrolase 1 (GCH1) gene may play important roles in Parkinson's disease (PD). However, there is a lack of comprehensive analysis of GCH1 genotypes, especially in non-coding regions. The aim of this study was to explore the genetic characteristics of GCH1, including rare and common variants in coding and non-coding regions, in a large population of PD patients in Chinese mainland, as well as the phenotypic characteristics of GCH1 variant carriers. METHODS: In the first cohort of this case-control study, we performed whole-exome sequencing in 1555 patients with early-onset or familial PD and 2234 healthy controls; then in the second cohort, whole-genome sequencing was performed in sporadic late-onset PD samples (1962 patients), as well as 1279 controls. Variants at target GCH1 regions were extracted, and then genetic and detailed phenotypic data were analyzed using regression models and the sequence kernel association test. We also performed a meta-analysis to correlate deleterious GCH1 variants with age at onset (AAO) in PD patients. RESULTS: For coding variants, we identified a significant burden of GCH1 deleterious variants in early-onset or familial PD cases compared to controls (1.2% vs 0.1%, P < 0.0001). In the analysis of possible regulatory variants in GCH1 non-coding regions, rs12323905 (P = 0.001, odds ratio = 1.19, 95%CI 1.07-1.32) was significantly associated with PD, and variant sets in untranslated regions and intron regions, GCH1 brain-specific expression quantitative trait loci, and two possible promoter/enhancer (GH14J054857 and GH14J054880) were suggestively associated with PD. Genotype-phenotype correlation analysis revealed that the carriers of GCH1 deleterious variants manifested younger AAO (P < 0.0001), and had milder motor symptoms, milder fatigue symptoms and more autonomic nervous dysfunctions. Meta-analysis of six studies demonstrated 6.4-year earlier onset in GCH1 deleterious variant carriers (P = 0.0009). CONCLUSIONS: The results highlight the importance of deleterious variants and non-coding variants of GCH1 in PD in Chinese mainland and suggest that GCH1 mutation can influence the PD phenotype, which may help design experimental studies to elucidate the mechanisms of GCH1 in the pathogenesis of PD.

Pharmacological enhancement of TFEB-mediated autophagy alleviated neuronal death in oxidative stress-induced Parkinson's disease models.

Autophagy, a conserved cellular degradation and recycling process, can be enhanced by nutrient depletion, oxidative stress or other harmful conditions to maintain cell survival. 6-Hydroxydopamine/ascorbic acid (6-OHDA/AA) is commonly used to induce experimental Parkinson's disease (PD) lesions by causing oxidative damage to dopaminergic neurons. Activation of autophagy has been observed in the 6-OHDA-induced PD models. However, the mechanism and exact role of autophagy activation in 6-OHDA PD model remain inconclusive. In this study, we report that autophagy was triggered via mucolipin 1/calcium/calcineurin/TFEB (transcription factor EB) pathway upon oxidative stress induced by 6-OHDA/AA. Interestingly, overexpression of TFEB alleviated 6-OHDA/AA toxicity. Moreover, autophagy enhancers, Torin1 (an mTOR-dependent TFEB/autophagy enhancer) and curcumin analog C1 (a TFEB-dependent and mTOR-independent autophagy enhancer), significantly rescued 6-OHDA/AA-induced cell death in SH-SY5Y cells, iPSC-derived DA neurons and mice nigral DA neurons. The behavioral abnormality of 6-OHDA/AA-treated mice can also be rescued by Torin 1 or C1 administration. The protective effects of Torin 1 and C1 can be blocked by autophagy inhibitors like chloroquine (CQ) or by knocking down autophagy-related genes TFEB and ATG5. Taken together, this study supports that TFEB-mediated autophagy is a survival mechanism during oxidative stress and pharmacological enhancement of this process is a neuroprotective strategy against oxidative stress-associated PD lesions.

Mutation analysis of CAPN1 in Chinese populations with spastic paraplegia and related neurodegenerative diseases.

BACKGROUND: Mutations in CAPN1 have recently been reported to cause the spastic paraplegia 76 (SPG76) subtype of hereditary spastic paraplegia (HSP). To investigate the role of CAPN1 in spastic paraplegia and other neurodegenerative diseases, including spinocerebellar ataxia (SCA), early-onset Parkinson's disease (EOPD), and amyotrophic lateral sclerosis (ALS) we conducted a mutation analysis of CAPN1 in a cohort of Chinese patients with SPG, SCA, EOPD, and ALS. METHODS: Variants of CAPN1 were detected in the three cohorts by Sanger or whole-exome sequencing, and all exons and exon-intron boundaries of CAPN1 were analysed. RESULTS: A novel CAPN1 splicing variant (NM_001198868: c.338-1G > A) identified in a familial SPG/SCA showed a complex phenotype, including spastic paraplegia, ataxia, and extensor plantar response. This mutation was confirmed by Sanger sequencing and completely co-segregated with the phenotypes. Sequencing of the cDNA from the three affected patients detected a guanine deletion (c.340_340delG) that was predicted to result in an early stop codon after 61 amino acids (p. D114Tfs*62). No CAPN1 pathogenic mutation was found in the EOPD or ALS groups. CONCLUSION: Our data reveal a novel CAPN1 mutation found in patients with SPG/SCA and emphasize the spastic and ataxic phenotypes of SPG76, but CAPN1 may not play a major role in EOPD and ALS.

Preliminary study of hsa-miR-626 change in the cerebrospinal fluid of Parkinson's disease patients.

microRNAs have been reported to suppress tumor growth, invasion, and metastasis and play roles in neurodegeneration disorders. Moreover, changes in microRNAs are found in the peripheral blood, cerebrospinal fluid (CSF), and brain tissues in patients of central nervous system diseases, including glioma, Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis and depression. Compared with other bodily fluids, CSF is the most accurate at representing the pathological processes of the brain. To understand whether microRNA expression may be dysregulated in the patients of PD, and to further discover potential diagnostic biomarkers and promising therapeutic targets for PD, we used real-time polymerase chain reaction (RT-PCR) to compare CSF microRNAs from 20 PD patients, 13 AD patients and 27 controls with other neurologic disorders such as encephalitis and Guillain-Barre syndrome. Finally, we found that the mean expression level of hsa-miR-626 was significantly reduced in the CSF of patients with PD compared with AD and controls. Our approach potentially identified a biomarker in CSF that upon further investigation, could be used for the detection, diagnosis, and monitoring of PD in combination with other PD biomarkers.