Lessons learned from CHMP2B, implications for frontotemporal dementia and amyotrophic lateral sclerosis.

Frontotemporal dementia (FTD) and Amyotrophic Lateral Sclerosis (ALS) are two neurodegenerative diseases with clinical, genetic and pathological overlap. As such, they are commonly regarded as a single spectrum disorder, with pure FTD and pure ALS representing distinct ends of a continuum. Dysfunctional endo-lysosomal and autophagic trafficking, leading to impaired proteostasis is common across the FTD-ALS spectrum. These pathways are, in part, mediated by CHMP2B, a protein that coordinates membrane scission events as a core component of the ESCRT machinery. Here we review how ALS and FTD disease causing mutations in CHMP2B have greatly contributed to our understanding of how endosomal-lysosomal and autophagic dysfunction contribute to neurodegeneration, and how in vitro and in vivo models have helped elucidate novel candidates for potential therapeutic intervention with implications across the FTD-ALS spectrum

Effect of Salt Concentration on Electrochemical Detection of DNA

Electrochemical approaches for biological sensing offer the potential advantages of facile sample preparation, fast response times, ease of parallel and multiplexed measurements, and the possibility of miniaturization (of sample sizes, electrodes, and associated electronics). All of these factors contribute towards the feasibility of electrochemical methods in biological sensing and analysis. This potential has already been achieved with the commercialization of blood glucose meters, which often rely on an electrochemical transduction mechanism. We have previously demonstrated the ability to electrochemically detect and differentiate complementary and mismatched DNA using our method of melting DNA duplexes at electrified gold surfaces, i.e. e-melting. Recently, we have optimized a new approach for preparing our DNA modified gold electrodes, and we are now able to precisely control the DNA surface coverage. In this work, we are using our improved methodology to explore the effects of electrolyte concentration (NaCl) on the electrochemical signal and the e-melting behavior. More specifically, our approach assumes a linear relationship between the amount of duplex DNA and the measured electrochemical signal. Here, we show that the concentration of salt in our buffer effects both the signal and the melting behavior. An understanding of these results are necessary for accurate interpretation of e-melting data

Electropolymerization of Polyaniline in the Presence of Ferricyanide

Here, we demonstrate that electropolymerization of aniline in the presence of ferricyanide leads to incorporation of the ferricyanide anions into the resulting polyaniline (PANI) film and an increase of the apparent deposition rate. Simultaneous cyclic voltammetry (CV) and quartz crystal microbalance (QCM) measurements in background electrolyte show a change in counter ion ingress/egress during oxidation and reduction of the film: an “inverted” mass transport behavior is observed, suggesting a cation-exchange mechanism for maintaining charge neutrality during oxidation of the leucoemeraldine to emeraldine state of the polymer. The behavior of the PANI-ferricyanide film is compared with films polymerized in the presence of potassium hexacyanoruthenate(II), FeCl3 and RuCl3. The potassium hexacyanoruthenate(II) enhances the polymerization rate and alters the electrochemical behavior of the film, much like ferricyanide, while FeCl3 and RuCl3 do not induce such an effect. Spectroscopic measurements confirm the presence of ferricyanide and hexacyanoruthenate(II) in the polymer

Synthesis and characterization of BODIPY-α-tocopherol : a new ligand to explore the intracellular transfer of Vitamin E

Since its discovery nearly a century ago, a-tocopherol (vitamin E) research has been mainly focused on its ability to terminate the cycle of lipid peroxidation in membranes. Nitrobenzoxadiazole fluorescent analogues were made previously to study the intracellular transfer of vitamin E in cells. However, these molecules were reportedly susceptible to photobleaching while under illumination for transfer assays and microscopy. Here is reported the synthesis of a series of fluorescent analogues of vitamin E incorporating the more robust dipyrrometheneboron difluoride fluorophore (BDP-a-Tocs; Aex = 507 nm, Aem = 511 nm). C8-BDP-a-Toc 42c, having an eight-carbon chain between the chromanol and fluorophore, wa<; shown to bind specifically to a-tocopherol transfer protein with a dissociation constant of approximately 100 nM. Another fluorescent analogue of vitamin E with a thienyl derivative of BODIPY that is excited and fluoresces at longer wavelengths (Aex = 561 nm, Aem = 570 nm) is in development