Y-39983, a Selective Rho-Kinase Inhibitor, Attenuates Experimental Autoimmune Encephalomyelitis via Inhibition of Demyelination

Abstract

Objective: Rho-associated kinase (ROCK) is a serine/threonine kinase and a major downstream effector of the small GTP-binding protein, Rho. Rho-ROCK triggers an intracellular signaling cascade that controls actin cytoskeleton and is essential for cell motility and adhesion, neurite outgrowth and retraction. In chronic disabling disease, multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE), demyelination and axonal damage are the major pathological changes contributing to neurological disability. We investigated the protective effect of a specific ROCK inhibitor, Y-39983, on demyelination and axonal damage in chronic EAE. Methods: Western blotting for myelin proteins, electron microscopy and solochrome cyanine staining was performed to evaluate demyelination while neurofilament proteins and cytoskeletal proteins including β-actin and β-tubulin were used to determine axonal damage in a chronic mouse model of EAE treated with Y-39983. Results: Y-39983 significantly suppressed clinical symptoms of EAE and prevented its relapse while increasing the amount of myelin proteins. No significant changes in neurofilaments and cytoskeletal proteins were observed compared with control EAE mice. The inhibition of demyelination by Y-39983 was confirmed by solochrome cyanine staining and electron microscopy. To further study the effect of Y-39983 on demyelination in EAE, we tested three major ROCK substrates, including myosin light chain phosphorylation, LIMK2 and collapsin response mediator protein-2. The activity of these molecules was decreased in EAE animals treated with Y-39983. Conclusion: The inhibitory effect of Y-39983 on demyelination is probably due to the inactivation of ROCK substrates, which are important for neurite outgrowth, growth cone collapse and demyelination of oligodendrocytes.

Zuo-Gui and You-Gui pills, two traditional Chinese herbal formulas, downregulated the expression of NogoA, NgR, and RhoA in rats with experimental autoimmune encephalomyelitis

“…Our data also showed similar results, indicating that NogoA, NgR, and RhoA mRNA and protein increased in the brains and/or spinal cords of rats during the acute and/or remission stages. In contrast, NogoA-knockout or -knockdown mice developed a milder disease course of EAE (Karnezis et al, 2004;Yang et al, 2010), and RhoA inhibitors have been shown to attenuate the progression of EAE (Gao et al, 2013). However, despite all of these advances in MS research, the neuroprotective treatment of MS is still a major challenge in the clinical setting.…”

Pharmacological Modulators of Small GTPases of Rho Family in Neurodegenerative Diseases

“…Treatment with ROCK inhibitor Y-39983, a more potent derivative of Y-27632, revealed a faster recovery from disease, decreased clinical symptoms, decreased inflammatory lesions, and decreased demyelination. This treatment led to an increase in myelinated axons and an increased complete recovery in MS model mice with experimental autoimmune encephalomyelitis or EAE (Gao et al, 2013 ).…”

Pharmacological Modulation of Functional Phenotypes of Microglia in Neurodegenerative Diseases

“…ROCK is a serine/threonine kinase and a key regulator in controlling formation of the actin cytoskeleton, as well as cell motility, and cell adhesion. Selective ROCK inhibitors, such as FSD-C10 or Y-39983, have been shown to exhibit therapeutic potential in an EAE model via attenuation of demyelination and neuroinflammation (Gao et al, 2013; Li et al, 2014). More recently, microglial treatment with a ROCK inhibitor Fasudil induced alteration in microglial phenotype polarization and functional plasticity, shifting the M1 to a M2 phenotype (Chen et al, 2014a).…”