Sacsin deletion decreases cell viscoelasticity and motility in a glial cell model of autosomal recessive spastic ataxia of Charlevoix Saguenay.

Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a movement disorder caused by loss-of-function mutations in the sacsin gene. The most common hallmark of this disease is the disruption of intermediate filament networks in cells as diverse as neurons, kidney cells, fibroblasts, astroglia and microglia. Intermediate filaments are the main filaments responsible for the mechanical and viscoelastic properties of cells and tissues, but these have never been investigated in the context of ARSACS. Here, we analyzed the consequences of sacsin loss on the mechanical functions of astroglial-like C6 cells. The phenotype of C6Sacs-/- cells was analyzed by immunocytochemistry, electron microscopy, mass spectrometry, atomic force microscopy and motility/proliferation assays. C6Sacs-/- cells presented an abnormal cytoskeletal and organelle distribution, global proteome alterations linked to cell motility and mechanics, a significant decrease in cell elasticity in the cytoplasm, and a striking reduction in cell motility. These mechanical alterations in glial-like cells could be especially relevant for neuroinflammation and glial scar formation upon CNS injury. Our results support a possible role for alterations in glial functions in ARSACS and provide new tools for understanding the glial-specific mechanisms involved in this movement disorder.