Stromal-derived Factor-1 (SDF-1) derived from vascular smooth muscle cells (VSMCs) contributes to vascular repair and remodeling in various vascular diseases. In this study, the mechanism underlying regulation of SDF-1 expression by interleukin-1 alpha (IL-1 alpha) was investigated in primary rat VSMCs. We found IL-1 alpha promotes SDF-1 expression by up-regulating CCAAT-enhancer-binding protein beta (C/EBP beta) in an I kappa B kinase beta (IKK beta) signaling-dependent manner. Moreover, IL-1 alpha-induced expression of C/EBP beta and SDF-1 was significantly potentiated by knockdown of transforming growth factor beta-activated kinase 1 (TAK1), an upstream activator of IKK beta signaling. In addition, we also demonstrated that TAK1/p38 mitogen-activated protein kinase (p38 MAPK) signaling exerted negative effect on IL-1 alpha-induced expression of C/EBP beta and SDF-1 through counteracting ROS-dependent up-regulation of nuclear factor erythroid 2-related factor 2 (NRF2). In conclusion, TAK1 acts as an important regulator of IL-1 alpha-induced SDF-1 expression in VSMCs, and modulating activity of TAK1 may serve as a potential strategy for modulating vascular repair and remodeling. (C) 2015 Elsevier Inc. All rights reserved.