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Pediatric multiple sclerosis (MS) is a chronic inflammatory neurologic disease that is challenging to diagnose and treat. Although there are many clinical parallels between pediatric-onset MS and adult-onset MS, there is also accumulating evidence of distinguishing clinical features that may, in part, arise from development-specific, neuroimmune processes governing MS pathogenesis in children. Here the authors describe the clinical features, diagnosis, and treatment of pediatric MS, with a particular focus on describing clinical features and highlighting new developments that promise a better understanding of pediatric MS pathogenesis. An important task that lies ahead for pediatric neurologists is better understanding the early gene-environment interaction that precipitates the first demyelinating event in pediatric MS. This area is of particular importance for understanding the MS etiology and the natural history of pediatric MS. Such understanding should in turn inform new developments in diagnostic tools, long-term therapies, and much-needed biomarkers. Such biomarkers are not only valuable for defining the disease onset, but also for monitoring both the treatment response and a disease evolution that spans multiple decades in children with MS. [ABSTRACT FROM AUTHOR]

Actin plays crucial roles in the mechanical response of cells to applied forces. For example, during cell adhesion, under the action of forces transmitted through integrins, actin filaments (F-actin) induce intracellular mechanical movements leading to changes in the cell shape. Muscle contraction results from the interaction of F-actin with the molecular motor myosin. Thus, understanding the origin of actin’s mechanical flexibility is required to understand the basis of fundamental cellular processes. F-actin results from the polymerization of globular actin (G-actin), which contains one tightly bound nucleotide (ATP or ADP). Experiments revealed that G-actin is more flexible than F-actin, but no molecular-level understanding of this differential behavior exists. To probe the basis of the mechanical behavior of actin, we study the force response of G-actin bound with ATP (G-ATP) or ADP (G-ADP). We investigate the global unfolding of G-actin under forces applied at its ends and its mechanical resistance along the actin−actin and actin−myosin bonds in F-actin. Our study reveals that the nucleotide plays an important role in the global unfolding of actin, leading to multiple unfolding scenarios which emphasize the differences between the G-ATP and G-ADP states. Furthermore, our simulations show that G-ATP is more flexible than G-ADP and that the actin−myosin interaction surface responds faster to force than the actin−actin interaction surface. The deformation of G-actin under tension revealed in our simulations correlates very well with experimental data on G-actin domain flexibility. [ABSTRACT FROM AUTHOR]