Actin–myosin network influences morphological response of neuronal cells to altered osmolarity

Abstract

Acute osmotic fluctuations in the brain occur during a number of clinical conditions and can result in a variety of adverse neurological symptoms. Osmotic perturbation can cause changes in the volumes of intra- and extracellular fluid and, due to the rigidity of the skull, can alter intracranial pressure thus making it difficult to analyze purely osmotic effects in vivo. The present study aims to determine the effects of changes in osmolarity on SH-SY5Y human neuroblastoma cells in vitro, and the role of the actin-myosin network in regulating this response. Cells were exposed to hyper- or hypoosmotic media and morphological and cytoskeletal responses were recorded. Hyperosmotic shock resulted in a drop in cell body volume and planar area, a persisting shape deformation, and increases in cellular translocation. Hypoosmotic shock did not significantly alter planar area, but caused a transient increase in cell body volume and an increase in cellular translocation via the development of small protrusions rich in actin. Disruption of the actin-myosin network with latrunculin and blebbistatin resulted in changes to volume and shape regulation, and a decrease in cellular translocation. In both osmotic perturbations, no apparent disruptions to cytoskeletal integrity were observed by light microscopy. Overall, because osmotically induced changes persisted even after volume regulation occurred, it is possible that osmotic stress may play a larger role in neurological dysfunction than currently believed.

Genomic differentiation and local adaptation on a microgeographic scale in a resident songbird

“…Of particular interest are several genes with putative links to cytoskeleton organization (MYH13, MYO18, MYO3, TTBK2, PAK3; Table ) that are associated with signals of elevated divergence between upland and salt marsh populations of San Francisco Bay song sparrows. Previous work has shown that the cytoskeleton, which is responsible for maintaining cell morphology, is a likely candidate for regulating cell volume response in the face of osmotic changes (Di Ciano‐Oliveira et al, 2006; Bober et al., 2015). Cytoskeletal reorganization may allow cells to resist volume changes through the reinforcement of cell structure (Di Ciano‐Oliveira et al, 2006), a potentially important adaptation to salt water environments.…”

Cytoskeletal Expression and Remodeling in Pluripotent Stem Cells

“…For example, shear stress applied to endothelial cells is transmitted via the cytoskeleton to the nucleus to induce changes in gene expression [ 15 ]. In addition, the cytoskeleton can regulate broader aspects of the mechanoresponse, such as constraining swelling of neuronal cells in response to osmotic stress [ 16 ]. In iPSCs specifically, hyperosmolarity also induces remodeling of cytoskeletal actin [ 17 ].…”