Interleukin-13-induced activation of signal transducer and activator of transcription 6 is mediated by an activation of Janus kinase 1 in cultured human bronchial smooth muscle cells

Abstract Background The current study was carried out to identify the JAK molecule(s) that is involved in the IL-13-induced activation of STAT6 in cultured human bronchial smooth muscle cells (hBSMCs). Methods Cultured hBSMCs were stimulated with IL-13 in the absence and presence of JAK inhibitor-I (a nonspecific JAKs inhibitor), tyrphostin-AG490 (a specific JAK2 inhibitor), WHI-P131 (a specific JAK3 inhibitor), or tyrphostin-AG9 (a specific Tyk2 inhibitor), and levels of phosphorylated STAT6 were measured by immunoblot analyses. Results The IL-13-induced phosphorylation of STAT6 was abolished by JAK inhibitor-I, whereas the other inhibitors had no significant effect. Conclusion These findings indicate that the STAT6 phosphorylation/activation induced by IL-13 is mediated by an activation of JAK1 in cultured hBSMCs.