The Rho-Kinase (ROCK) Inhibitor Y-27632 Protects Against Excitotoxicity-Induced Neuronal Death In Vivo and In Vitro

Abstract

Rho-associated coil kinase (ROCK) inhibitors reportedly prevent neurodegeneration, and abnormal ROCK activation in the central nervous system induces neurite collapse and retraction. However, it is unclear whether the ROCK inhibitor Y-27632 directly protects hippocampal neurons from excitotoxicity. Here, we determined the effects of Y-27632 on neuroprotection following kainic acid (KA)-induced seizures in mice and during glutamate-induced excitotoxicity in HT22 cells. One day after Y-27632 injection, mice were treated with KA and killed 1-2 days later. Fluoro-Jade B and rapid Golgi staining showed that Y-27632 protected against KA-induced neurodegeneration and neurite dystrophy. Y-27632 inhibited increases in hippocampal RhoA and ROCK2 in KA-treated mice as determined by western blot analysis. Immunohistochemical analysis revealed ROCK2-positive neurons and astrocytes in the KA-treated hippocampus. In HT22 cells, Y-27632 also protected neurons and neurite formation during glutamate-induced excitotoxicity in vitro. These results indicate that ROCK inhibition modulates neurite growth and protects neurons from excitotoxicity-induced cell death.

Ginsenoside Rg1 Protects against Oxidative Stress-induced Neuronal Apoptosis through Myosin IIA-actin Related Cytoskeletal Reorganization

“…ROCK is reported to regulate MLC phosphorylation 22. Abnormal activation of ROCK has been observed in the pathophysiology of CNS diseases 55, 56. Our results revealed that ROCK1 was cleaved to form a 30-kDa band upon H 2 O 2 exposure, while ROCK2 was not cleaved.…”

Selective inhibition of brain endothelial Rho-kinase-2 provides optimal protection of an in vitro blood-brain barrier from tissue-type plasminogen activator and plasmin

“…ROCK-2, the main brain isoform of Rho-kinase [25, 26], has been primarily localised to neurons [25, 27] and non-vascular astrocytes [27, 28] rather than to blood vessels. Because the relevance of ROCK-2 to neurovascular function has not been extensively studied, we first looked at steady state levels of the two ROCK isoform transcripts in human and mouse brain cells which comprise the BBB, namely brain endothelial cells (BECs) and astrocytes, and further compared them to the abundance of ROCK mRNA in neurons.…”

“…Two isoforms of ROCK have been described, ROCK-1 (p160ROCK; ROKβ) and ROCK-2 (ROKα) [10, 11]. ROCK-1 is ubiquitously expressed (with low levels in brain and muscle), while ROCK-2 is abundant in the brain [25, 26], particularly in neurons [25, 27] and in reactive astrocytes [27, 28]. The two isoforms share 65% overall amino-acid sequence identity and particularly high homology in the kinase domain (92%) [26, 29].…”

Neuronal Apoptosis Induced by Selective Inhibition of Rac GTPase versus Global Suppression of Rho Family GTPases Is Mediated by Alterations in Distinct Mitogen-activated Protein Kinase Signaling Cascades

“…The blots shown are representative of three independent experiments. effect in various in vitro and in vivo models of neuronal cell death, such as cerebral ischemia and excitotoxicity (29,30). In addition to Rho kinase, Rho GTPase has many other downstream effectors that could contribute to neuronal death via a mechanism that is independent of caspase activation.…”