Serum Deprivation of Mesenchymal Stem Cells Improves Exosome Activity and Alters Lipid and Protein Composition.

Exosomes can serve as delivery vehicles for advanced therapeutics. The components necessary and sufficient to support exosomal delivery have not been established. Here we connect biochemical composition and activity of exosomes to optimize exosome-mediated delivery of small interfering RNAs (siRNAs).

The role of microglia in processing and spreading of bioactive tau seeds in Alzheimer's disease.

Background: Misfolding of microtubule-associated protein tau (MAPT) within neurons into neurofibrillary tangles is an important pathological feature of Alzheimer's disease (AD). Tau pathology correlates with cognitive decline in AD and follows a stereotypical anatomical course; several recent studies indicate that tau pathology spreads inter-neuronally via misfolded tau "seeds." Previous research has focused on neurons as the source of these tau seeds.

Transvascular Delivery of Hydrophobically Modified siRNAs: Gene Silencing in the Rat Brain upon Disruption of the Blood-Brain Barrier.

Effective transvascular delivery of therapeutic oligonucleotides to the brain presents a major hurdle to the development of gene silencing technologies for treatment of genetically defined neurological disorders. Distribution to the brain after systemic administrations is hampered by the low permeability of the blood-brain barrier (BBB) and the rapid clearance kinetics of these drugs from the blood. Here we show that transient osmotic disruption of the BBB enables transvascular delivery of hydrophobically modified small interfering RNA (hsiRNA) to the rat brain.

Non-motor features of Parkinson's disease in a nested case-control study of US men.

Background: Several non-motor features may individually contribute to identify prodromal Parkinson's disease (PD), but little is known on how they interact.

Methods: We conducted a case-control study nested within the Health Professionals Follow-up Study in a large cohort of men age 40-75 at recruitment in 1986. Cases (n=120) had confirmed PD, were<85 in January 2012, returned a 2012 questionnaire with questions on probable rapid eye movement sleep behaviour disorder (RBD) and constipation sent to all cohort participants and completed in 2014 the Brief Smell Identification Test and a questionnaire assessing parkinsonism and other non-motor PD features (including depressive symptoms, excessive daytime sleepiness, impaired colour vision and body pain).

Models for predicting risk of dementia: a systematic review.

Background: Information from well-established dementia risk models can guide targeted intervention to prevent dementia, in addition to the main purpose of quantifying the probability of developing dementia in the future.

Methods: We conducted a systematic review of published studies on existing dementia risk models. The models were assessed by sensitivity, specificity and area under the curve (AUC) from receiver operating characteristic analysis.

Optimized Cholesterol-siRNA Chemistry Improves Productive Loading onto Extracellular Vesicles.

Extracellular vesicles are promising delivery vesicles for therapeutic RNAs. Small interfering RNA (siRNA) conjugation to cholesterol enables efficient and reproducible loading of extracellular vesicles with the therapeutic cargo. siRNAs are typically chemically modified to fit an application.

Calsenilin, a Presenilin Interactor, Regulates RhoA Signaling and Neurite Outgrowth.

Calsenilin modulates A-type potassium channels, regulates presenilin-mediated γ-secretase activity, and represses prodynorphin and genes expression. RhoA is involved in various cellular functions including proliferation, differentiation, migration, transcription, and regulation of the actin cytoskeleton. Although recent studies demonstrate that calsenilin can directly interact with RhoA and that RhoA inactivation is essential for neuritogenesis, it is uncertain whether there is a link between calsenilin and RhoA-regulated neuritogenesis.

Red hair, variants, and risk for Parkinson's disease - a meta-analysis.

Several studies have been conducted with mixed results since our initial report of increased Parkinson's disease risk in individuals with red hair and/or red hair-associated p.R151C variant of the gene, both of which confer high melanoma risk. We performed a meta-analysis of six publications on red hair, , and Parkinson's disease.

Tunneling nanotube (TNT)-mediated neuron-to neuron transfer of pathological Tau protein assemblies.

A given cell makes exchanges with its neighbors through a variety of means ranging from diffusible factors to vesicles. Cells use also tunneling nanotubes (TNTs), filamentous-actin-containing membranous structures that bridge and connect cells. First described in immune cells, TNTs facilitate HIV-1 transfer and are found in various cell types, including neurons.

Fragile X syndrome: Are signaling lipids the missing culprits?

Fragile X syndrome (FXS) is the most common cause of inherited intellectual disability and autism. FXS results from the absence of FMRP, an RNA binding protein associated to ribosomes that influences the translation of specific mRNAs in post-synaptic compartments of neurons. The main molecular consequence of the absence of FMRP is an excessive translation of neuronal protein in several areas of the brain.

A simultaneous one pot synthesis of two fractal structures via swapping two fractal reaction kinetic states.

We introduce a new class of fractal reaction kinetics wherein two or more distinct fractal structures are synthesized as parts of a singular cascade reaction in a single chemical beaker. Two examples: sphere ↔ spiral & triangle ↔ square fractals, grow 10(6) orders from a single dendrimer (8 nm) to the visible scale.

Structural studies on the mechanism of protein aggregation in age related neurodegenerative diseases.

The progression of many neurodegenerative diseases is assumed to be caused by misfolding of specific characteristic diseases related proteins, resulting in aggregation and fibril formation of these proteins. Protein misfolding associated age related diseases, although different in disease manifestations, share striking similarities. In all cases, one disease protein aggregates and loses its function or additionally shows a toxic gain of function.

Does the Mutant CAG Expansion in Huntingtin mRNA Interfere with Exonucleolytic Cleavage of its First Exon?

Background: Silencing mutant huntingtin mRNA by RNA interference (RNAi) is a therapeutic strategy for Huntington's disease. RNAi induces specific endonucleolytic cleavage of the target HTT mRNA, followed by exonucleolytic processing of the cleaved mRNA fragments.

Objectives: We investigated the clearance of huntingtin mRNA cleavage products following RNAi, to find if particular huntingtin mRNA sequences persist.

Hydrophobically Modified siRNAs Silence Huntingtin mRNA in Primary Neurons and Mouse Brain.

Applications of RNA interference for neuroscience research have been limited by a lack of simple and efficient methods to deliver oligonucleotides to primary neurons in culture and to the brain. Here, we show that primary neurons rapidly internalize hydrophobically modified siRNAs (hsiRNAs) added directly to the culture medium without lipid formulation. We identify functional hsiRNAs targeting the mRNA of huntingtin, the mutation of which is responsible for Huntington's disease, and show that direct uptake in neurons induces potent and specific silencing in vitro.

Identification of neurotoxic cytokines by profiling Alzheimer's disease tissues and neuron culture viability screening.

Alzheimer's disease (AD) therapeutics based on the amyloid hypothesis have shown minimal efficacy in patients, suggesting that the activity of amyloid beta (Aβ) represents only one aspect of AD pathogenesis. Since neuroinflammation is thought to play an important role in AD, we hypothesized that cytokines may play a direct role in promoting neuronal death. Here, we profiled cytokine expression in a small cohort of human AD and control brain tissues.

TR-FRET Assays for Endogenous Huntingtin Protein Level in Mouse Cells.

High-throughput measurement of huntingtin (Htt) levels is useful for Huntington's disease research. For example, identification of genetic or chemical modifiers that reduce Htt levels by high-throughput screening provides promising strategy for HD drug discovery. In the human cells, high-throughput measurement of Htt levels has been established based on the Time Resolved-Fluorescence Resonance Energy Transfer (TR-FRET) technology, using the 2B7/MW1 antibody pair.

Tracking the earliest pathologic changes in Alzheimer disease.

A current challenge in Alzheimer disease (AD) research is to identify the sequence of pathologic changes that occurs during preclinical stages of disease in advance of cognitive decline. The timing of appearance of the 2 pathologic hallmarks of AD-amyloid deposition and tau-mediated neurodegeneration-is a particular topic of debate, with researchers drawing on a broad range of genetic, neuroimaging, fluid biomarker, animal, and autopsy studies to piece together the series of events ultimately leading to the plaques, neurofibrillary tangles, and cognitive deficits that define AD.

Drugging unconventional targets: insights from Huntington's disease.

Classical targeted drug discovery is based on targeting druggable targets, typically kinases and receptors of which the function can be agonized or antagonized. This strategy meets difficulties in cases such as Huntington's disease (HD) and similar neurodegenerative disorders, where the pathological function of the protein causing the disease is not clear. HD is caused by mutant HTT protein (mHTT) containing an expanded polyglutamine (polyQ) stretch, but the function of mHTT and how mHTT causes HD are unknown, thus preventing efforts to screen for mHTT 'inhibitors'.

Differential relationships of reactive astrocytes and microglia to fibrillar amyloid deposits in Alzheimer disease.

Although it is clear that astrocytes and microglia cluster around dense-core amyloid plaques in Alzheimer disease (AD), whether they are primarily attracted to amyloid deposits or are just reacting to plaque-associated neuritic damage remains elusive. We postulate that astrocytes and microglia may differentially respond to fibrillar amyloid β. Therefore, we quantified the size distribution of dense-core thioflavin-S (ThioS)-positive plaques in the temporal neocortex of 40 AD patients and the microglial and astrocyte responses in their vicinity (≤50 μm) and performed correlations between both measures.

Genome-wide increase in histone H2A ubiquitylation in a mouse model of Huntington's disease.

Background: Huntington's disease (HD) is a neurodegenerative disorder with selective vulnerability of striatal neurons and involves extensive transcriptional dysregulation early in the disease process. Previous work in cell and mouse models has shown that histone modifications are altered in HD. Specifically, monoubiquitylated histone H2A (uH2A) is present at the promoters of downregulated genes which led to the hypothesis that uH2A plays a role in transcriptional silencing in HD.

Distinct roles in vivo for the ubiquitin-proteasome system and the autophagy-lysosomal pathway in the degradation of α-synuclein.

Increased intracellular levels of α-synuclein are implicated in Parkinson's disease and related disorders and may be caused by alterations in the ubiquitin-proteasome system (UPS) or the autophagy-lysosomal pathway (ALP). A critical question remains how α-synuclein is degraded by neurons in vivo. To address this, our study uses α-synuclein transgenic mice, expressing human α-synuclein or α-synuclein-eGFP under the (h)PDGF-β promoter, in combination with in vivo pharmacologic and multiphoton imaging strategies to systematically test degradation pathways in the living mouse brain.

Mitochondrial Parkin recruitment is impaired in neurons derived from mutant PINK1 induced pluripotent stem cells.

Genetic Parkinson disease (PD) has been associated with mutations in PINK1, a gene encoding a mitochondrial kinase implicated in the regulation of mitochondrial degradation. While the studies so far examined PINK1 function in non-neuronal systems or through PINK1 knockdown approaches, there is an imperative to examine the role of endogenous PINK1 in appropriate human-derived and biologically relevant cell models. Here we report the generation of induced pluripotent stem (iPS) cells from skin fibroblasts taken from three PD patients with nonsense (c.