SelectiveROCK2 inhibition in focal cerebral ischemia

Abstract

Objective Rho-associated kinase (ROCK) is a key regulator of numerous processes in multiple cell types relevant in stroke pathophysiology. ROCK inhibitors have improved outcome in experimental models of acute ischemic or hemorrhagic stroke. However, the relevant ROCK isoform (ROCK1 or ROCK2) in acute stroke is not known. Methods We characterized the pharmacodynamic and pharmacokinetic profile, and tested the efficacy and safety of a novel selective ROCK2 inhibitor KD025 (formerly SLx-2119) in focal cerebral ischemia models in mice. Results KD025 dose-dependently reduced infarct volume after transient middle cerebral artery occlusion. The therapeutic window was at least 3 hours from stroke onset, and the efficacy was sustained for at least 4 weeks. KD025 was at least as efficacious in aged, diabetic or female mice, as in normal adult males. Concurrent treatment with atorvastatin was safe, but not additive or synergistic. KD025 was also safe in a permanent ischemia model, albeit with diminished efficacy. As one mechanism of protection, KD025 improved cortical perfusion in a distal middle cerebral artery occlusion model, implicating enhanced collateral flow. Unlike isoform-nonselective ROCK inhibitors, KD025 did not cause significant hypotension, a dose-limiting side effect in acute ischemic stroke. Interpretation Altogether, these data show that KD025 is efficacious and safe in acute focal cerebral ischemia in mice, implicating ROCK2 as the relevant isoform in acute ischemic stroke. Data suggest that selective ROCK2 inhibition has a favorable safety profile to facilitate clinical translation.

Heterogeneous Impact of ROCK2 on Carotid and Cerebrovascular Function

“…In relation to selectivity, two of the most commonly used inhibitors of ROCK (Y-27632 and fasudil) can also inhibit other enzymes, with fasudil being the least selective of the two 30, 31 . Of importance for the present study, Y-27632 and fasudil have similar inhibitory constants ( K i ) for ROCK1 and ROCK2 4 . In contrast, SLX-2119 is highly selective for ROCK2 compared with ROCK1 ( K i : >10,000 nmol/L for ROCK1 vs 41 nmol/L for ROCK2) 4 .…”

“…The cumulative addition of SLX-2119 (0.1 nmol/L - 10 μmol/L) dilated parenchymal arterioles (Figure 6B). At 1 μmol/L, a concentration where SLX-2119 is highly selective for ROCK2 vs ROCK1 4 , SLX-2119 dilated parenchymal arterioles by 78.9±4.0%. In contrast, addition of vehicle (DMSO) had minimal effect on myogenic tone (Figure 6B).…”

“…Based largely on studies using pharmacological inhibitors that do not distinguish between isoforms, ROCK has been implicated in various diseases including hypertension 1, 2 , diabetes 3 and stroke 4, 5 .…”

“…Because of its key role in hypertension and vessel disease, we used a model of Ang II-induced vascular dysfunction for portions of the study. As part of our approach, we tested effects of a new, selective ROCK2 inhibitor, SLX-2119 (also known as KD025) 4, 23 on regulation of vascular tone in carotid arteries and resistance vessels in brain. Our findings suggest that ROCK2 plays a key role in endothelial dysfunction produced in response to direct RhoA activation or Ang II.…”

Idiopathic Pulmonary Fibrosis: Molecular Endotypes of Fibrosis Stratifying Existing and Emerging Therapies

“…KD025 (Slx-2119) is a selective inhibitor of Rho-associated protein kinase 2 which is an effector of system of Rho GTP-ases, basic for cytoskeletal activity, motility, and cell contraction [122]. In phase 1 trial on healthy subjects, KD025 reduces the levels of IL-21 and IL-17 secreted by T cells, but it does not seem to reduce the response to stimulus of IFN-γ [123].…”