Addendum: The antibody aducanumab reduces Aβ plaques in Alzheimer's disease.

This corrects the article DOI: 10.1038/nature21361. Erratum for An intermediate-mass black hole in the centre of the globular cluster 47 Tucanae. [Nature. 2017] The antibody aducanumab reduces Aβ plaques in Alzheimer's disease. [Nature. 2016

Efficient elimination of MELAS-associated m.3243G mutant mitochondrial DNA by an engineered mitoARCUS nuclease

Nuclease-mediated editing of heteroplasmic mitochondrial DNA (mtDNA) seeks to preferentially cleave and eliminate mutant mtDNA, leaving wild-type genomes to repopulate the cell and shift mtDNA heteroplasmy. Various technologies are available, but many suffer from limitations based on size and/or specificity. The use of ARCUS nucleases, derived from naturally occurring I-CreI, avoids these pitfalls due to their small size, single-component protein structure and high specificity resulting from a robust protein-engineering process. Here we describe the development of a mitochondrial-targeted ARCUS (mitoARCUS) nuclease designed to target one of the most common pathogenic mtDNA mutations, m.3243A>G. mitoARCUS robustly eliminated mutant mtDNA without cutting wild-type mtDNA, allowing for shifts in heteroplasmy and concomitant improvements in mitochondrial protein steady-state levels and respiration. In vivo efficacy was demonstrated using a m.3243A>G xenograft mouse model with mitoARCUS delivered systemically by adeno-associated virus. Together, these data support the development of mitoARCUS as an in vivo gene-editing therapeutic for m.3243A>G-associated diseases

Proof-of-Mechanism Study of the Phosphodiesterase 10 Inhibitor RG7203 in Patients With Schizophrenia and Negative Symptoms

BACKGROUND:Reduced activation of dopamine D1receptor signaling may be implicated in reward functioning as apotential driver of negative symptoms in schizophrenia. Phosphodiesterase 10A (PDE10A), an enzyme that is highlyexpressed in the striatum, modulates both dopamine D2- and D1-dependent signaling.METHODS:We assessed whether augmentation of D1signaling by the PDE10 inhibitor RG7203 enhances imagingand behavioral markers of reward functions in patients with schizophrenia and negative symptoms. In a 3-period,double-blind, crossover study, we investigated the effects of RG7203 (5 mg and 15 mg doses) and placebo asadjunctive treatment to stable background antipsychotic treatment in patients with chronic schizophrenia withmoderate levels of negative symptoms. Effects on reward functioning and reward-based effortful behavior wereevaluated using the monetary incentive delay task during functional magnetic resonance imaging and the effort-cost-benefit and working memory reinforcement learning tasks.RESULTS:Patients (N= 33; 30 male, mean age6SD 36.667.0 years; Positive and Negative Syndrome Scalenegative symptom factor score 23.063.5 at screening) were assessed at three study centers in the United States; 24patients completed the study. RG7203 at 5 mg significantly increased reward expectation–related activity in themonetary incentive delay task, but in the context of significantly decreased overall activity across all task conditions.CONCLUSIONS:In contrast to our expectations, RG7203 significantly worsened reward-based effortful behavior andindices of reward learning. The results do not support the utility of RG7203 as adjunctive treatment for negativesymptoms in patients with schizophrenia

Patients with autism spectrum disorders display reproducible functional connectivity alterations

Despite the high clinical burden, little is known about pathophysiology underlying autism spectrum disorder(ASD). Recent resting-state functional magnetic resonance imaging (rs-fMRI) studies have found atypical synchro-nization of brain activity in ASD. However, no consensus has been reached on the nature and clinical relevance ofthese alterations. Here, we addressed these questions in four large ASD cohorts. Using rs-fMRI, we identified func-tional connectivity alterations associated with ASD. We tested for associations of these imaging phenotypes withclinical and demographic factors such as age, sex, medication status, and clinical symptom severity. Our resultsshowed reproducible patterns of ASD-associated functional hyper- and hypoconnectivity. Hypoconnectivity wasprimarily restricted to sensory-motor regions, whereas hyperconnectivity hubs were predominately located inprefrontal and parietal cortices. Shifts in cortico-cortical between-network connectivity from outside to withinthe identified regions were shown to be a key driver of these abnormalities. This reproducible pathophysiologicalphenotype was partially associated with core ASD symptoms related to communication and daily living skills andwas not affected by age, sex, or medication status. Although the large effect sizes in standardized cohorts areencouraging with respect to potential application as a treatment and for patient stratification, the moderate linkto clinical symptoms and the large overlap with healthy controls currently limit the usability of identified altera-tions as diagnostic or efficacy readout

A Phase II Study to Evaluate the Safety and Efficacy of Prasinezumab in Early Parkinson's Disease (PASADENA): Rationale, Design, and Baseline Data.

Background: Currently available treatments for Parkinson's disease (PD) do not slow clinical progression nor target alpha-synuclein, a key protein associated with the disease. Objective: The study objective was to evaluate the efficacy and safety of prasinezumab, a humanized monoclonal antibody that binds aggregated alpha-synuclein, in individuals with early PD. Methods: The PASADENA study is a multicenter, randomized, double-blind, placebo-controlled treatment study. Individuals with early PD, recruited across the US and Europe, received monthly intravenous doses of prasinezumab (1,500 or 4,500 mg) or placebo for a 52-week period (Part 1), followed by a 52-week extension (Part 2) in which all participants received active treatment. Key inclusion criteria were: aged 40-80 years; Hoehn & Yahr (H&Y) Stage I or II; time from diagnosis ≤2 years; having bradykinesia plus one other cardinal sign of PD (e.g., resting tremor, rigidity); DAT-SPECT imaging consistent with PD; and either treatment naïve or on a stable monoamine oxidase B (MAO-B) inhibitor dose. Study design assumptions for sample size and study duration were built using a patient cohort from the Parkinson's Progression Marker Initiative (PPMI). In this report, baseline characteristics are compared between the treatment-naïve and MAO-B inhibitor-treated PASADENA cohorts and between the PASADENA and PPMI populations. Results: Of the 443 patients screened, 316 were enrolled into the PASADENA study between June 2017 and November 2018, with an average age of 59.9 years and 67.4% being male. Mean time from diagnosis at baseline was 10.11 months, with 75.3% in H&Y Stage II. Baseline motor and non-motor symptoms (assessed using Movement Disorder Society-Unified Parkinson's Disease Rating Scale [MDS-UPDRS]) were similar in severity between the MAO-B inhibitor-treated and treatment-naïve PASADENA cohorts (MDS-UPDRS sum of Parts I + II + III [standard deviation (SD)]; 30.21 [11.96], 32.10 [13.20], respectively). The overall PASADENA population (63.6% treatment naïve and 36.4% on MAO-B inhibitor) showed a similar severity in MDS-UPDRS scores (e.g., MDS-UPDRS sum of Parts I + II + III [SD]; 31.41 [12.78], 32.63 [13.04], respectively) to the PPMI cohort (all treatment naïve). Conclusions: The PASADENA study population is suitable to investigate the potential of prasinezumab to slow disease progression in individuals with early PD. Trial Registration: NCT03100149

The antibody aducanumab reduces Aβ plaques in Alzheimer's disease

Alzheimer's disease (AD) is characterized by deposition of amyloid-β (Aβ) plaques and neurofibrillary tangles in the brain, accompanied by synaptic dysfunction and neurodegeneration. Antibody-based immunotherapy against Aβ to trigger its clearance or mitigate its neurotoxicity has so far been unsuccessful. Here we report the generation of aducanumab, a human monoclonal antibody that selectively targets aggregated Aβ. In a transgenic mouse model of AD, aducanumab is shown to enter the brain, bind parenchymal Aβ, and reduce soluble and insoluble Aβ in a dose-dependent manner. In patients with prodromal or mild AD, one year of monthly intravenous infusions of aducanumab reduces brain Aβ in a dose- and time-dependent manner. This is accompanied by a slowing of clinical decline measured by Clinical Dementia Rating-Sum of Boxes and Mini Mental State Examination scores. The main safety and tolerability findings are amyloid-related imaging abnormalities. These results justify further development of aducanumab for the treatment of AD. Should the slowing of clinical decline be confirmed in ongoing phase 3 clinical trials, it would provide compelling support for the amyloid hypothesis