IMPORTANCE Convergent biological, epidemiological, and clinical data identified urate elevation as a candidate strategy for slowing disability progression in Parkinson disease (PD).OBJECTIVE To determine the safety, tolerability, and urate-elevating capability of the urate precursor inosine in early PD and to assess its suitability and potential design features for a disease-modification trial. DESIGN, SETTING, AND PARTICIPANTSThe Safety of Urate Elevation in PD (SURE-PD) study, a randomized, double-blind, placebo-controlled, dose-ranging trial of inosine, enrolled participants from 2009 to 2011 and followed them for up to 25 months at outpatient visits to 17 credentialed clinical study sites of the Parkinson Study Group across the United States. Seventy-five consenting adults (mean age, 62 years; 55% women) with early PD not yet requiring symptomatic treatment and a serum urate concentration less than 6 mg/dL (the approximate population median) were enrolled.INTERVENTIONS Participants were randomized to 1 of 3 treatment arms: placebo or inosine titrated to produce mild (6.1-7.0 mg/dL) or moderate (7.1-8.0 mg/dL) serum urate elevation using 500-mg capsules taken orally up to 2 capsules 3 times per day. They were followed for up to 24 months (median, 18 months) while receiving the study drug plus 1 washout month. MAIN OUTCOMES AND MEASURESThe prespecified primary outcomes were absence of unacceptable serious adverse events (safety), continued treatment without adverse event requiring dose reduction (tolerability), and elevation of urate assessed serially in serum and once (at 3 months) in cerebrospinal fluid.RESULTS Serious adverse events (17), including infrequent cardiovascular events, occurred at the same or lower rates in the inosine groups relative to placebo. No participant developed gout and 3 receiving inosine developed symptomatic urolithiasis. Treatment was tolerated by 95% of participants at 6 months, and no participant withdrew because of an adverse event. Serum urate rose by 2.3 and 3.0 mg/dL in the 2 inosine groups (P < .001 for each) vs placebo, and cerebrospinal fluid urate level was greater in both inosine groups (P = .006 and <.001, respectively). Secondary analyses demonstrated nonfutility of inosine treatment for slowing disability.CONCLUSIONS AND RELEVANCE Inosine was generally safe, tolerable, and effective in raising serum and cerebrospinal fluid urate levels in early PD. The findings support advancing to more definitive development of inosine as a potential disease-modifying therapy for PD. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00833690

By using the large cytoplasmic domain of the nicotinic acetylcholine receptor (AChR) ␣4 subunit as a bait in the yeast two-hybrid system, we isolated the first cytosolic protein, 14-3-3, known to interact directly with neuronal AChRs. 14-3-3 is a member of a family of proteins that function as regulatory or chaperone/ scaffolding/adaptor proteins. 14-3-3 interacted with the recombinant ␣4 subunit alone in tsA 201 cells following activation of cAMP-dependent protein kinase by forskolin. The interaction of 14-3-3 with recombinant ␣4 subunits was abolished when serine 441 of the ␣4 subunit was mutated to alanine (␣4 S441A ). The surface levels of recombinant wild-type ␣4␤2 AChRs were ϳ2-fold higher than those of mutant ␣4 S441A ␤2 AChRs. The interaction significantly increased the steady state levels of the ␣4 subunit and ␣4␤2 AChRs but not that of the mutant ␣4 S441A subunit or mutant ␣4 S441A ␤2 AChRs. The EC 50 values for activation by acetylcholine were not significantly different for ␣4␤2 AChRs and ␣4 S441A ␤2 AChRs coexpressed with 14-3-3 in oocytes following treatment with forskolin. 14-3-3 coimmunopurified with native ␣4 AChRs from brain. These results support a role for 14-3-3 in dynamically regulating the expression levels of ␣4␤2 AChRs through its interaction with the ␣4 subunit. Neuronal nicotinic acetylcholine receptors (AChR)1 are a family of ligand-gated, cation-selective, homo-or heteropentameric ion channels expressed in the peripheral and central nervous system (1, 2). A multitude of neuronal AChR subtypes assembled from different combinations of ␣2-␣9 and ␤2-␤4 subunits have been identified (3,4 (7), and show attenuated self-administration of nicotine (8) suggesting that ␣4␤2 AChRs have a role in mediating addiction to nicotine. The normal and pathophysiological functions mediated by ␣4␤2 AChRs are of significant importance to human health. Some inherited forms of epilepsy, such as the autosomal dominant nocturnal frontal lobe epilepsies, are caused by ␣4␤2 AChRs harboring at least two separate mutations within their ␣4 subunit (9 -12). Most recently, ␣4␤2 AChRs, among other ␤2 subunit-containing AChRs, have been implicated in neuronal survival during aging, as surmised from the neurodegeneration observed in ␤2-subunit knock-out mice (13).The ␣4 subunit, like the other AChR subunits, consists of an extracellular N-terminal domain, followed by three transmembrane domains (M1-M3), a large cytoplasmic domain, a fourth transmembrane domain (M4), and a short extracellular C terminus. The large cytoplasmic domain is highly divergent among the various subunits, and this sequence divergence presumably provides the diversity necessary for different AChR subtypes to interact directly with cytosolic proteins of different function. To identify such proteins associated with ␣4␤2 AChRs, we used the large cytoplasmic domain of the ␣4 subunit as a bait to screen a mouse brain cDNA yeast two-hybrid library. Here we describe the isolation of a known protein termed 14-3-3. The 14-3-3 proteins family consists of sev...

Transdermal rotigotine, when titrated to a dosage of 6 mg/24 h, was effective for the treatment of early-stage Parkinson disease in this trial. Adverse events were similar to those found with other transdermal systems and dopamine agonists.

A Randomized Clinical Trial of High-Dosage Coenzyme Q10 in Early Parkinson Disease No Evidence of Benefit The Parkinson Study Group QE3 Investigators IMPORTANCE Coenzyme Q10 (CoQ10), an antioxidant that supports mitochondrial function, has been shown in preclinical Parkinson disease (PD) models to reduce the loss of dopamine neurons, and was safe and well tolerated in early-phase human studies. A previous phase II study suggested possible clinical benefit. OBJECTIVE To examine whether CoQ10 could slow disease progression in early PD. DESIGN, SETTING, AND PARTICIPANTS A phase III randomized, placebo-controlled, double-blind clinical trial at 67 North American sites consisting of participants 30 years of age or older who received a diagnosis of PD within 5 years and who had the following inclusion criteria: the presence of a rest tremor, bradykinesia, and rigidity; a modified Hoehn and Yahr stage of 2.5 or less; and no anticipated need for dopaminergic therapy within 3 months. Exclusion criteria included the use of any PD medication within 60 days, the use of any symptomatic PD medication for more than 90 days, atypical or drug-induced parkinsonism, a Unified Parkinson's Disease Rating Scale (UPDRS) rest tremor score of 3 or greater for any limb, a Mini-Mental State Examination score of 25 or less, a history of stroke, the use of certain supplements, and substantial recent exposure to CoQ10. Of 696 participants screened, 78 were found to be ineligible, and 18 declined participation. INTERVENTIONS The remaining 600 participants were randomly assigned to receive placebo, 1200 mg/d of CoQ10, or 2400 mg/d of CoQ10; all participants received 1200 IU/d of vitamin E. MAIN OUTCOMES AND MEASURES Participants were observed for 16 months or until a disability requiring dopaminergic treatment. The prospectively defined primary outcome measure was the change in total UPDRS score (Parts I-III) from baseline to final visit. The study was powered to detect a 3-point difference between an active treatment and placebo. RESULTS The baseline characteristics of the participants were well balanced, the mean age was 62.5 years, 66% of participants were male, and the mean baseline total UPDRS score was 22.7. A total of 267 participants required treatment (94 received placebo, 87 received 1200 mg/d of CoQ10, and 86 received 2400 mg/d of CoQ10), and 65 participants (29 who received placebo, 19 who received 1200 mg/d of CoQ10, and 17 who received 2400 mg/d of CoQ10) withdrew prematurely. Treatments were well tolerated with no safety concerns. The study was terminated after a prespecified futility criterion was reached. At study termination, both active treatment groups showed slight adverse trends relative to placebo. Adjusted mean changes (worsening) in total UPDRS scores from baseline to final visit were 6.9 points (placebo), 7.5 points (1200 mg/d of CoQ10; P = .49 relative to placebo), and 8.0 points (2400 mg/d of CoQ10; P = .21 relative to placebo). CONCLUSIONS AND RELEVANCE Coenzyme Q10 was safe and well tolerated in this population, bu...

The structural determinants of nicotinic acetylcholine receptor (AChR) trafficking have yet to be fully elucidated. Hydrophobic residues occur within short motifs important for endoplasmic reticulum (ER) export or endocytotic trafficking. Hence, we tested whether highly conserved hydrophobic residues, primarily leucines, in the cytoplasmic domain of the ␣4␤2 AChR subunits were required for cell surface expression of ␣4␤2 AChRs. Mutation of F350, L351, L357, and L358 to alanine in the ␣4 AChR subunit attenuates cell surface expression of mutant ␣4␤2 AChRs. Mutation of F342, L343, L349, and L350 to alanine at homologous positions in the ␤2 AChR subunit abolishes cell surface expression of mutant ␣4␤2 AChRs. The hydrophobic nature of the leucine residue is a primary determinant of its function because mutation of L343 to another hydrophobic amino acid, phenylalanine, in the ␤2 AChR subunit only poorly inhibits trafficking of mutant ␣4␤2 AChR to the cell surface. All mutant ␣4␤2 AChRs exhibit high-affinity binding for [ 3 H]epibatidine. In both tsA201 cells and differentiated SH-SY5Y neural cells, wild-type ␣4␤2 AChRs colocalize with the Golgi marker giantin, whereas mutant ␣4␤2 AChRs fail to do so. The striking difference between mutant ␣4 versus mutant ␤2 AChR subunits on cell surface expression of mutant ␣4␤2 AChRs points to a cooperative or regulatory role for the ␣4 AChR subunit and an obligatory role for the ␤2 AChR subunit in ER export. Collectively, our results identify, for the first time, residues within AChR subunits that are essential structural determinants of ␣4␤2 AChR ER export.