Amyotrophic lateral sclerosis (ALS) is a devastating progressive neurodegenerative disease affecting primarily the upper and lower motor neurons. A common feature of all ALS cases is a well-characterized neuroinflammatory reaction within the central nervous system (CNS). However, much less is known about the role of the peripheral immune system and its interplay with CNS resident immune cells in motor neuron degeneration. Here, we characterized peripheral monocytes in both temporal and spatial dimensions of ALS pathogenesis. We found the circulating monocytes to be deregulated in ALS regarding subtype constitution, function and gene expression. Moreover, we show that CNS infiltration of peripheral monocytes correlates with improved motor neuron survival in a genetic ALS mouse model. Furthermore, application of human immunoglobulins or fusion proteins containing only the human Fc, but not the Fab antibody fragment, increased CNS invasion of peripheral monocytes and delayed the disease onset. Our results underline the importance of peripheral monocytes in ALS pathogenesis and are in agreement with a protective role of monocytes in the early phase of the disease. The possibility to boost this beneficial function of peripheral monocytes by application of human immunoglobulins should be evaluated in clinical trials.

Currently, Alzheimer's disease (AD) accounts for more than half of all dementia cases. Although genetics, age, and environmental factors affect the disease, the cause of AD is not yet fully known. Various drugs have been proposed for the prevention and treatment of AD, but the delivery of these therapeutic agents to the brain is difficult. The blood-brain barrier prevents systemic drugs from accessing the central nervous system and designing a suitable system to overcome this barrier has attracted much attention. The intranasal pathway, given its proximity to the brain, provides a great opportunity for drug delivery. Understanding the physiological characteristics of the nose can be useful in selecting the appropriate carrier and material. Some of the emerging vehicles used for nose-to-brain delivery of anti-AD drugs are natural (such as chitosan) and polymeric (such as poly(lactic-co-glycolic acid) and polyethylene glycol) nanoparticles (NPs). This review discusses the hypotheses for AD pathogenesis and highlights recent advances in the applications of natural and polymeric NPs for treatment. The fundamental and applied aspects of this approach for nasal drug delivery to the brain are reviewed here with thoughts on what is needed for the field to mature also provided.

Genetically encoded Förster resonance energy transfer (FRET)-based tension sensors measure piconewton-scale forces across individual molecules in living cells or whole organisms. These biosensors show comparably high FRET efficiencies in the absence of tension, but FRET quickly decreases when forces are applied. In this article, we describe how such biosensors can be generated for a specific protein of interest, and we discuss controls to confirm that the observed differences in FRET efficiency reflect changes in molecular tension. These FRET efficiency changes can be related to mechanical forces as the FRET-force relationship of the employed tension sensor modules are calibrated. We provide information on construct generation, expression in cells, and image acquisition using live-cell fluorescence lifetime imaging microscopy (FLIM). Moreover, we describe how to analyze, statistically evaluate, and interpret the resulting data sets. Together, these protocols should enable the reader to plan, execute, and interpret FRET-based tension sensor experiments. C 2019 by John Wiley & Sons, Inc.Keywords: biosensor r FLIM r FRET r mechanotransduction r tension sensor

Adhesion of monocytes to micro-injuries on arterial walls is an important early step in the occurrence and development of degenerative atherosclerotic lesions. At these injuries, collagen is exposed to the blood stream. We are interested whether age influences monocyte adhesion to collagen under flow, and hence influences the susceptibility to arteriosclerotic lesions. Therefore, we studied adhesion and rolling of human peripheral blood monocytes from old and young individuals on collagen type I coated surface under shear flow. We find that firm adhesion of monocytes to collagen type I is elevated in old individuals. Pre-stimulation by lipopolysaccharide increases the firm adhesion of monocytes homogeneously in older individuals, but heterogeneously in young individuals. Blocking integrin αx showed that adhesion of monocytes to collagen type I is specific to the main collagen binding integrin αxβ2. Surprisingly, we find no significant age-dependent difference in gene expression of integrin αx or integrin β2. However, if all integrins are activated from the outside, no differences exist between the age groups. Altered integrin activation therefore causes the increased adhesion. Our results show that the basal increase in integrin activation in monocytes from old individuals increases monocyte adhesion to collagen and therefore the risk for arteriosclerotic plaques.