Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

Amyloid fibrils nucleated and organized by DNA origami constructions

Amyloid fibrils are ordered, insoluble protein aggregates that are associated with neurodegenerative conditions such as Alzheimer's disease. The fibrils have a common rod-like core structure, formed from an elongated stack of β-strands, and have a rigidity similar to that of silk (Young's modulus of 0.2-14 GPa). They also exhibit high thermal and chemical stability and can be assembled in vitro from short synthetic non-disease-related peptides. As a result, they are of significant interest in the development of self-assembled materials for bionanotechnology applications. Synthetic DNA molecules have previously been used to form intricate structures and organize other materials such as metal nanoparticles and could in principle be used to nucleate and organize amyloid fibrils. Here, we show that DNA origami nanotubes can sheathe amyloid fibrils formed within them. The fibrils are built by modifying the synthetic peptide fragment corresponding to residues 105-115 of the amyloidogenic protein transthyretin and a DNA origami construct is used to form 20-helix DNA nanotubes with sufficient space for the fibrils inside. Once formed, the fibril-filled nanotubes can be organized onto predefined two-dimensional platforms via DNA-DNA hybridization interactions

Extended glare point velocimetry and sizing for bubbly flows

A novel measuring technique for bubbly flows, named glare point velocimetry and sizing (GPVS), was developed in order to measure both bubble size and velocity with high accuracy in a 2D plane. This is accomplished by observing glare points in-focus under an observation angle of 96°. When a second laser-sheet is added, even higher accuracies are obtained and the relative refractive index of the bubble can be measured. It also allows non-spherical bubbles to be rejected and arbitrary angles to be used (e.g. 90°). The accuracy of the size and refractive index measurements was found to be within 1.3%.info:eu-repo/semantics/publishe

Huntingtin Inclusions Trigger Cellular Quiescence, Deactivate Apoptosis, and Lead to Delayed Necrosis

Competing models exist in the literature for the relationship between mutant Huntingtin exon 1 (Httex1) inclusion formation and toxicity. In one, inclusions are adaptive by sequestering the proteotoxicity of soluble Httex1. In the other, inclusions compromise cellular activity as a result of proteome co-aggregation. Using a biosensor of Httex1 conformation in mammalian cell models, we discovered a mechanism that reconciles these competing models. Newly formed inclusions were composed of disordered Httex1 and ribonucleoproteins. As inclusions matured, Httex1 reconfigured into amyloid, and other glutamine-rich and prion domain-containing proteins were recruited. Soluble Httex1 caused a hyperpolarized mitochondrial membrane potential, increased reactive oxygen species, and promoted apoptosis. Inclusion formation triggered a collapsed mitochondrial potential, cellular quiescence, and deactivated apoptosis. We propose a revised model where sequestration of soluble Httex1 inclusions can remove the trigger for apoptosis but also co-aggregate other proteins, which curtails cellular metabolism and leads to a slow death by necrosis