Selective oral ROCK2 inhibitor down-regulates IL-21 and IL-17 secretion in human T cells via STAT3-dependent mechanism

• Published in: Proceedings of the National Academy of Sciences - PNAS 2014-11, Vol.111 (47), p.16814-16819
• Main Authors: Zanin-Zhorov, Alexandra, Weiss, Jonathan M., Nyuydzefe, Melanie S., Chen, Wei, Scher, Jose U., Mo, Rigen, Depoil, David, Rao, Nishta, Liu, Ben, Wei, Jianlu, Lucas, Sarah, Koslow, Matthew, Roche, Maria, Schueller, Olivier, Weiss, Sara, Poyurovsky, Masha V., Tonra, James, Hippen, Keli L, Dustin, Michael L., Blazar, Bruce R., Liu, Chuan-ju, Waksal, Samuel D., Dinarello, Charles A.
• Format: Article
• Language: English
• Subjects: Administration, Oral; Arthritis; Autoimmunity; Biological Sciences; Blood; CD4-Positive T-Lymphocytes - drug effects; CD4-Positive T-Lymphocytes - secretion; Cells, Cultured; Cytokines; Down regulation; Humans; Interleukin-17 - genetics; Interleukin-17 - secretion; Interleukins - genetics; Interleukins - secretion; Kinases; Phosphorylation; Promoter Regions, Genetic; Protein Kinase Inhibitors - administration & dosage; Protein Kinase Inhibitors - pharmacology; rho-Associated Kinases - antagonists & inhibitors; Rodents; Secretion; Signal transduction; Small interfering RNA; STAT3 Transcription Factor - metabolism; STAT3 Transcription Factor - physiology; T cell receptors; T lymphocytes; Transcription, Genetic; Up regulation
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1414189111

Significance Rho-associated kinase 2 (ROCK2) is implicated in the regulation of proinflammatory cytokines, such as IL-17 and IL-21, and the development of autoimmunity in mice. However, the role of ROCK2 signaling pathway in regulation of immune responses in humans is still an enigma. Here we show that targeted ROCK2 inhibition down-regulates proinflammatory responses via concurrent regulation of STAT3/STAT5 phosphorylation and shifting Th17/Treg balance in human T cells with a minimal effect on the rest of the immune response. This work provides previously unidentified insights into the molecular mechanism of ROCK2-mediated modulation of the immune response in man and has profound implications for development of a selective ROCK2 inhibitor as a new therapeutic target for autoimmunity treatment. Rho-associated kinase 2 (ROCK2) regulates the secretion of proinflammatory cytokines and the development of autoimmunity in mice. Data from a phase 1 clinical trial demonstrate that oral administration of KD025, a selective ROCK2 inhibitor, to healthy human subjects down-regulates the ability of T cells to secrete IL-21 and IL-17 by 90% and 60%, respectively, but not IFN-γ in response to T-cell receptor stimulation in vitro. Pharmacological inhibition with KD025 or siRNA-mediated inhibition of ROCK2, but not ROCK1, significantly diminished STAT3 phosphorylation and binding to IL-17 and IL-21 promoters and reduced IFN regulatory factor 4 and nuclear hormone RAR-related orphan receptor γt protein levels in T cells derived from healthy subjects or rheumatoid arthritis patients. Simultaneously, treatment with KD025 also promotes the suppressive function of regulatory T cells through up-regulation of STAT5 phosphorylation and positive regulation of forkhead box p3 expression. The administration of KD025 in vivo down-regulates the progression of collagen-induced arthritis in mice via targeting of the Th17-mediated pathway. Thus, ROCK2 signaling appears to be instrumental in regulating the balance between proinflammatory and regulatory T-cell subsets. Targeting of ROCK2 in man may therefore restore disrupted immune homeostasis and have a role in the treatment of autoimmunity.