James W. Langston

• MD
• Parkinson’s Institute

Mutations in the Leucine Rich Repeat Protein Kinase 2 gene (LRRK2) are genetic predispositions for Parkinson's Disease, of which the G2019S (GS) missense mutation is the most common. GS-LRRK2 has a hyperactive kinase, and although numerous drug discovery programs have targeted the LRRK2 kinase, few have reached clinical trials. We recently reported...

Objective The aim of this study was to search for genes/variants that modify the effect of LRRK2 mutations in terms of penetrance and age‐at‐onset of Parkinson's disease. Methods We performed the first genomewide association study of penetrance and age‐at‐onset of Parkinson's disease in LRRK2 mutation carriers (776 cases and 1,103 non‐cases at the...

Objective: The aim of this study was to search for genes/variants that modify the effect of LRRK2 mutations in terms of penetrance and age-at-onset of Parkinson's disease. Methods: We performed the first genome-wide association study of penetrance and age-at-onset of Parkinson's disease in LRRK2 mutation carriers (776 cases and 1,103 non-cases at t...

In an unbiased genome-wide screen for copy number variants (CNVs) on a cohort of Parkinson's disease (PD) patients, we identified in one patient a complex chromosomal rearrangement involving the nucleotide binding protein-like (NUBPL) gene on chromosome 14q12. We noted that mutations in the NUBPL gene had been reported as causing autosomal recessiv...

Background The penetrance of leucine rich repeat kinase 2 (LRRK2 ) mutations is incomplete and may be influenced by environmental and/or other genetic factors. Nonsteroidal anti‐inflammatory drugs (NSAIDs) are known to reduce inflammation and may lower Parkinson's disease (PD) risk, but their role in LRRK2 ‐associated PD is unknown. Objectives The...

During the 1990s, we estimated the genetic contribution to Parkinson's disease risk in a large, population‐based twin registry. Because many unaffected twins were still alive, previous concordance estimates were based on incomplete information. Ninety‐five percent of twins are now deceased. Here, we update concordance and heritability through 2015...

The “Iowa kindred,” a large Iowan family with autosomal-dominant Parkinson’s disease, has been followed clinically since the 1920s at the Mayo Clinic. In 2003, the genetic cause was determined to be a 1.7 Mb triplication of the alpha-synuclein genomic locus. Affected individuals present with an early-onset, severe parkinsonism-dementia syndrome. He...

Background Mutations in the leucine rich repeat kinase 2 (LRRK2) gene are among the most common genetic causes of Lewy body Parkinson’s disease (PD). However, LRRK2 mutations can also lead to a variety of pathological phenotypes other than typical PD, including relatively pure nigrostriatal cell loss without alpha-synuclein-positive Lewy bodies or...

Large, non-coding pentanucleotide repeat expansions of ATTCT in intron 9 of the ATXN10 gene typically cause progressive spinocerebellar ataxia with or without seizures and present neuropathologically with Purkinje cell loss resulting in symmetrical cerebellar atrophy. These ATXN10 repeat expansions can be interrupted by sequence motifs which have b...

The identification of MPTP, a relatively simple compound which causes selective degeneration of the substantia nigra after systemic administration, has had an a significant impact on the understanding and treatment of Parkinson’s disease (PD) over the last 30 years. This article is prefaced by the intriguing “medical detective story” that lead to t...

Background: Heart rate variability is reduced in idiopathic PD, indicating cardiac autonomic dysfunction likely resulting from peripheral autonomic synucleinopathy. Little is known about heart rate variability in leucine-rich repeat kinase 2-associated PD. Objectives: This study investigated heart rate variability in LRRK2-associated PD. Method...

Mutations in the PARKIN gene (chromosome 6q25-27) were first described in 1998 in families with “juvenile” autosomal recessive parkinsonism. More than 180 causative variants in the PARKIN gene have been identified; point mutations and copy number variants (i.e., exon deletions or duplications) occur at nearly equal frequencies.1 PARKIN is one of th...

Here we prioritize as multisystem Lewy body disease (MLBD) those genetic forms of Parkinson's disease that point the way toward a mechanistic understanding of the majority of sporadic disease. Pathological diagnosis of genetic subtypes offers the prospect of distinguishing different mechanistic trajectories with a common mutational etiology, differ...

To determine ways to improve diagnostic accuracy of multiple system atrophy (MSA), we assessed the diagnostic process in patients who came to autopsy with antemortem diagnosis of MSA by comparing clinical and pathologic features between those who proved to have MSA and those who did not. We focus on likely explanations for misdiagnosis. This is a r...

Activating mutations in the LRRK2 gene are the most common cause of inherited Parkinson's disease (PD). LRRK2 is phosphorylated on a cluster of phosphosites including Ser910, 935, 955 and 973, which are dephosphorylated in several PD-related LRRK2 mutants [N1347H, R1441C/G, Y1699C and I2020T] linking the regulation of these sites to PD. These serin...

Importance Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of genetic Parkinson disease (PD) known to date. The clinical features of manifesting LRRK2 mutation carriers are generally indistinguishable from those of patients with sporadic PD. However, some PD cases associated with LRRK2 mutations lack Lewy bodies (LBs),...

Parkinson disease (PD) is a multi-factorial neurodegenerative disorder with loss of dopaminergic neurons in the substantia nigra and characteristic intracellular inclusions, called Lewy bodies. Genetic predisposition, such as point mutations and copy number variants of the SNCA gene locus can cause very similar PD-like neurodegeneration. The impact...

Detailed analysis of disease-affected tissue provides insight into molecular mechanisms contributing to pathogenesis. Substantia nigra, striatum, and cortex are functionally connected with increasing degrees of alpha-synuclein pathology in Parkinson's disease. We undertook functional and causal pathway analysis of gene expression and proteomic alte...

Increased gut permeability, inflammation, and colonic α-synuclein pathology are present in early Parkinson's disease (PD) and have been proposed to contribute to PD pathogenesis. Peptidoglycan is a structural component of the bacterial cell wall. Peptidoglycan recognition proteins (PGRPs) maintain healthy gut microbial flora by regulating the immun...

Parkinson's disease associated mutations in leucine rich repeat kinase 2 (LRRK2) impair mitochondrial function and increase the vulnerability of induced pluripotent stem cell (iPSC)-derived neural cells from patients to oxidative stress. Since mitochondrial DNA (mtDNA) damage can compromise mitochondrial function, we examined whether LRRK2 mutation...

Alpha-synuclein protein is strongly implicated in the pathogenesis Parkinson's disease. Increased expression of α-synuclein due to genetic multiplication or point mutations leads to early onset disease. While α-synuclein is known to modulate membrane vesicle dynamics, it is not clear if this activity is involved in the pathogenic process or if meas...

Microglia isolated from line 26/syn null or α-syn null littermates were stimulated with LPS in the presence or absence of Brefeldin A. Tissue culture supernatant was assessed for TNF-α production by ELISA (n = 2; 5 pups/GT/expt +/− s.e.m *p≤0.001 when α-syn TG samples were compared with non-TG). (EPS)

Background / Purpose: Parkinson’s disease is the second most common neurodegenerative diseases, affecting specific mid-brain dopaminergic (DA) neurons. We are developing a functional experimental tool using induced pluripotent stem cell (iPSC)-derived DA neurons from a patient with LRRK2 parkinsonism which presents the most common form of genetic...

Paraquat is one of the most widely used herbicides worldwide. It produces a Parkinson's disease (PD) model in rodents through redox cycling and oxidative stress (OS) and is associated with PD risk in humans. Glutathione transferases provide cellular protection against OS and could potentially modulate paraquat toxicity. We investigated PD risk asso...

Background / Purpose: Neuronal stem cells (NPCs) derived from Parkinson’s patients with mutations are more susceptible to cellular stress and bioenergetic challenges. The accumulated stress then contributes to the predisposition of NPC-derived differentiated dopaminergic neurons to premature cell death. The objective was to investigate cellular a...

Variants in the LRRK2 gene are well-characterized genetic predisposing factors for PD worldwide, and LRRK2-associated PD is often indistinguishable from idiopathic PD (IPD). However, considerable heterogeneity of LRRK2-PD suggests the existence of additional genetic and/or environmental modifiers for LRRK2 carriers, which have yet to be confirmed b...

Several case reports have linked solvent exposure to Parkinson disease (PD), but few studies have assessed associations with specific agents using an analytic epidemiologic design. We tested the hypothesis that exposure to specific solvents is associated with PD risk using a discordant twin pair design. Ninety-nine twin pairs discordant for PD asce...

Fetal transplantation for Parkinson disease (PD) had been considered a promising therapeutic strategy; however, reports of Lewy bodies (LBs) and Lewy neurites (LNs) in engrafted tissue adds to controversy surrounding this treatment for PD. The brain of a PD patient who had fetal transplantation 14 years before death was evaluated. The graft was stu...

Efficient in vitro differentiation into specific cell types is more important than ever after the breakthrough in nuclear reprogramming of somatic cells and its potential for disease modeling and drug screening. Key success factors for neuronal differentiation are the yield of desired neuronal marker expression, reproducibility, length, and cost....

To test the hypothesis that variability in SNCA Rep1, a polymorphic dinucleotide microsatellite in the promoter region of the gene encoding α-synuclein, modifies the association between head injury and Parkinson's disease (PD) risk. Participants in the Farming and Movement Evaluation (FAME) and the Study of Environmental Association and Risk of Par...

Background / Purpose: The aim of this study was to use an embryoid body approach to generate neural stem cells. Main conclusion: We found that using SB431542 and dorsomorphine is a more efficient way of inducing neural lineage.

Transcript analysis of midbrain dopaminergic neuron differentiation over 50 days for pluripotent lines Trpl17, Ctrl2 and H9. Pluripotency markers Oct4, c-Myc and TERT are turn off at the neural stem cell stage (NSC) and remain silenced in DA neurons. Notably, DNMT3B (a denovo DNA methyltransferase) shows moderate silencing at the NSC stage, while e...

Epigenetic status of pluripotency and imprinted genes. (A) Methylation status of NANOG and OCT4 promoters as determined by bisulfide sequencing in untransduced fibroblasts (Trpl-HDF and Nrml-HDF) and pluripotent iPSC lines (Trpl17 and Nrml2). (B) Differential methylated regions on paternal, KCNQ1OT1, and maternal, H19, imprinting sites display bala...

Neuronal differentiation. (A) Day 50 DA neuron differentiation culture phase contrast micrographs of Trpl17, Nrml2 and H9. (B) Day 50 DA neuron differentiation IF confocal 20× micrograph showing a 423 µm TH+ axon extending from a DA neuron. (C) Trpl17 derived neurons express PAX6 in culture with TH and Nestin. Scale bars represent 200 µm (a) and 10...

Full heatmap display of Fluidigm qPCR results. Gene list is filtered for those with ≥30% samples containing valid CT counts. Genes and samples were complete linkage clustered with uncentered correlation similarity metric using Cluster. Results were visualized in TreeView. The set was analyzed for correllation groups with known biochemical similarit...

IF confocal micrographs for Trpl17 derived neurons. Colocalization of SNCA and TH immunoreacivity, suggesting that DA neurons can express alpha-synuclein. (TIF)

(A) IF shows immunoreactivity colocalization of Ubiquitin and TH when Ubiquitin was expressed at a low level. However, cells demonstrating strong Ubiquitin accumulation immunoreactivity were not positive for TH. (B) Confocal micrographs showing activated Caspase-3 in Trpl17 DA cultures with and without H2O2 treatment. Scale bars = 10 µm (a,b) and 1...

Pluripotency related telomerase activity. Relative telomerase activity in: untransduced HDF lines (Trpl2-HDF and Ctrl2-HDF); pluripotent iPSC lines Trpl17, Trpl46, Ctrl2 and Nrml3; hESC line HSF8; differentiated iPSC lines 4c17 and Ctrl2; negative buffer only control; and a TSR8 positive control. Heat inactivation used as an internal control. *p<0....

Differentiation of iPSC lines. (A) Confocal micrographs of α-Fetoprotein protein is detected by antibody recognition in EB spontaneous differentiation in iPSC lines Trpl17 and Ctrl2, indicative of endoderm lineage. Scale bars = 100 µm. (B) Further characterization of iPSC pluripotency. iPSC lines Trpl17 and Ctrl2 are capable of forming embryoid bod...

Patient clinical report and additional methods are described. (DOCX)

Characteristics of iPSC lines. (A) Expression of pluripotency related markers alkaline phosphatase (AP), TRA-160, SSEA3, Nanog, TRA-181, SSEA4 and the absence of SSEA1 are shown for SNCA triplication iPSC clones Trpl8 and Trpl43. Stability of reprogrammed lines was assessed through (B) Spectral SKY karyotype analysis of iPSC lines. Shown here are r...

Schematic of DA neuron differentiation from pluripotent stem cells. Protocol requires 50 days of differentiation and two passaging steps. Working concentrations for growth factors are: Sonic Hedgehog (SHH)-(Cys-24 modified) = 200 ng/ml, FGF8 = 100 ng/ml, Brain-Derived Neurtrophic Factor (BDNF) = 20 ng/ml, Glial Derived Neurtrophic Factor (GDNF) = 1...

Parkinson's disease (PD) is an incurable age-related neurodegenerative disorder affecting both the central and peripheral nervous systems. Although common, the etiology of PD remains poorly understood. Genetic studies infer that the disease results from a complex interaction between genetics and environment and there is growing evidence that PD may...

Background / Purpose: Parkinson’s disease (PD) is one of the most common neurodegenerative diseases of aging, affecting 1-2% of the population over 65 years of age. It is estimated that the number of prevalent cases of PD world-wide will double by the year 2030. There is no cure or effective way to slow disease progression, and the causes of the...

The ADAGIO study demonstrated a symptomatic benefit for rasagiline in early Parkinson's disease (PD) and suggested a disease-modifying effect. Evidence indicates that mitochondrial dysfunction plays a role in the pathogenesis of PD and that this may be the site of effect for rasagiline. In this systematic review, evidence for the role of mitochondr...

This chapter provides a comprehensive review of the rapidly increasing array of clinical signs and symptoms that can now justifiably be called pre-motor Parkinson's disease (PD). Many of these overlap with other clinical entities. However, it is now becoming clear that these pre-motor features of PD have the potential to enhance our understanding o...

Oxidative damage of membrane polyunsaturated fatty acids (PUFA) is thought to play a major role in mitochondrial dysfunction related to Parkinson's disease (PD). The toxic products formed by PUFA oxidation inflict further damage on cellular components and contribute to neuronal degeneration. Here, we tested the hypothesis that isotopic reinforcemen...

Using a family study design, we describe the motor and nonmotor phenotype in probands with LRRK2 G2019S mutations and family members and compare these individuals to patients with idiopathic Parkinson disease (iPD) and unrelated controls. Probands with G2019S mutations and their first-degree relatives, subjects with iPD, and unrelated control subje...

Plot of -values around RIT2/SYT4. Colors depict the squared correlation () of each SNP with rs4130047. For details, see Figure 1. (TIFF)

Success rate (versus total power) by disease. Replications = number of associations we successfully replicated. Expected = number of associations we expected to replicate. Attempts = number of associations we attempted to replicate. The blue dot represents our success ratio (number of successful replications divided by number of expected replicatio...

External cross-validation AUC difference test using bias-corrected models. Each row of the table represents a comparison of a “test” risk prediction model based on the significance threshold indicated in the first column against a “reference” model containing only SNPs found in genome-wide significant regions. In all cases, reported AUCs have been...

Bias-corrected model. This model, which achieves a covariate-adjusted AUC of 0.614 on the NINDS data, was obtained by training on the 23andMe cohort, using the subset of SNPs that were shared with the NINDS cohort. refers to the weight for each SNP (i.e., the log odds ratio per copy of the alphabetically lesser allele), and is the weight used in th...

Exclusionary conditions. People reporting any of the above diagnoses were excluded from the analysis. (PDF)

Quantile-quantile plot Observed -values versus theoretical -values under the null. The genomic control inflation factor for the study was and is shown by the red line. (TIFF)

Plot of -values around rs2823357 and USP25. Colors depict the squared correlation () of each SNP with rs2823357. For details, see Figure 1. (TIFF)

Details for all SNPs with -values under . See Table 2 for details. (XLS)

Test for heterogeneity. The low confidence group consisted of participants who did not answer a questionnaire, whereas the high confidence group consisted of participants who did. The second and third columns show the estimated log odds-ratio for each SNP from Table 2 using only low and high confidence data, respectively. The fourth column shows th...

Genotype by phenotype tables for SNPs in Table 2. (PDF)

Internal and external cross-validation AUC difference test for sparse logistic regression models. Rows and columns of each table correspond to models being compared, and are labeled using the theoretical upper bound on of the model for that particular row or column. Elements of the tables are one-sided -value tests for the alternative hypothesis th...

Bias-corrected model. This model, which achieves a covariate-adjusted AUC of 0.608 on the NINDS data, was obtained by training on the 23andMe cohort, using the subset of SNPs that were shared with the NINDS cohort. refers to the weight for each SNP (i.e., the log odds ratio per copy of the alphabetically lesser allele), and is the weight used in th...

(PDF)

Although the causes of Parkinson's disease (PD) are thought to be primarily environmental, recent studies suggest that a number of genes influence susceptibility. Using targeted case recruitment and online survey instruments, we conducted the largest case-control genome-wide association study (GWAS) of PD based on a single collection of individuals...

The ADAGIO study investigated whether rasagiline has disease-modifying effects in Parkinson's disease. Rasagiline 1 mg per day, but not 2 mg per day, was shown to be efficacious in the primary analysis. Here, we report additional secondary and post-hoc analyses of the ADAGIO study. ADAGIO was a placebo-controlled, double-blind, multicentre, delayed...

Studies of Parkinson's disease (PD) have been hindered by lack of access to affected human dopaminergic (DA) neurons. Here, we report generation of induced pluripotent stem cells that carry the p.G2019S mutation (G2019S-iPSCs) in the Leucine-Rich Repeat Kinase-2 (LRRK2) gene, the most common PD-related mutation, and their differentiation into DA ne...

Mitochondrial dysfunction and oxidative stress are pathophysiologic mechanisms implicated in experimental models and genetic forms of Parkinson's disease (PD). Certain pesticides may affect these mechanisms, but no pesticide has been definitively associated with PD in humans. Our goal was to determine whether pesticides that cause mitochondrial dys...

Mitochondrial dysfunction has been frequently implicated in the neurodegenerative process that underlies Parkinson's disease (PD), but the basis for this impairment is not fully understood. The goal of this study was to investigate the effects of α-synuclein (α-syn) gene multiplication on mitochondrial function in human tissue. To investigate this...

The aim of this study was to test the hypothesis that patients with REM sleep behavior disorder, many of whom will develop Parkinson's disease (PD) or a related synucleinopathy, will demonstrate decreased heart rate variability (HRV) compared with a group of age-matched controls as measured by an electrocardiogram during wakefulness. We compared HR...

Our previous work had shown that long-term nicotine administration improved dopaminergic markers and nicotinic receptors (nAChRs) in the striatum of monkeys with nigrostriatal damage. The present experiments were done to determine whether nicotine treatment also led to changes in the substantia nigra, the region containing dopaminergic cell bodies....

The study of mechanisms that underlie Parkinson's disease (PD), as well as translational drug development, has been hindered by the lack of appropriate models. Both cell culture systems and animal models have limitations, and to date none faithfully recapitulate all of the clinical and pathological phenotypes of the disease. In this review we exami...

A therapy that slows disease progression is the major unmet need in Parkinson's disease. In this double-blind trial, we examined the possibility that rasagiline has disease-modifying effects in Parkinson's disease. A total of 1176 subjects with untreated Parkinson's disease were randomly assigned to receive rasagiline (at a dose of either 1 mg or 2...

We examined risk of parkinsonism in occupations (agriculture, education, health care, welding, and mining) and toxicant exposures (solvents and pesticides) putatively associated with parkinsonism. To investigate occupations, specific job tasks, or exposures and risk of parkinsonism and clinical subtypes. Case-control. Eight movement disorders cente...

Because of its normal function in synaptic plasticity and pathologic involvement in age-related neurodegenerative diseases, the protein alpha-synuclein could play an important role in aging processes. Here we compared alpha-synuclein expression in the substantia nigra and other brain regions of young (2-month-old), middle-aged (10-month-old), and o...

A growing body of experimental and clinical literature indicates an association between Gaucher disease and parkinsonism, raising the possibility that convergent mechanisms may contribute to neurodegeneration in these disorders. The aim of this study was to determine whether there is a relationship between alpha-synuclein (alpha-syn), a key protein...