Transforming growth factor alpha (TGF) may be an important mediator of wound healing and the injury response. Human bone marrow mesenchymal stem cells (MSCs) release vascular endothelial growth factor (VEGF) as a potentially beneficial paracrine response; however, it remains unknown whether TGF stimulates the production of VEGF from MSCs and, if so, by which mechanisms. We hypothesized that TGF would increase human MSC VEGF production by MEK, PI-3 K, ERK and JNK dependent mechanisms. To study this, MSCs were cultured and divided into the following groups: 1) with vehicle; 2) with various stimulants alone: TGF, TNF, or TGF+TNF; and 3) with individual kinase inhibitors alone (two different inhibitors for each of the following kinases: MEK, PI3-K, ERK, or JNK); and 4) with the above stimulants and each of the eight inhibitors. After 24 h incubation, a TGF dose response curve demonstrated that low dose TGF (500pg/ml) suppressed MSC production of VEGF compared to vehicle (502±16 pg/10⁵ cells/ml to 332±9 pg/10⁵ cells/ml) while high dose TGF (250ng/ml) significantly increased MSC VEGF production (603±24 pg/10⁵ cells/ml). High dose TGF also increased TNF-stimulated release of VEGF from MSCs. MSCs exposed to TGF and/or TNF also demonstrated increased activation of PI-3 K, JNK, and ERK. The TGF-stimulated production of VEGF by MSCs and the additive effect of TNF and TGF on VEGF production were abolished by MEK and PI-3 K inhibition, but not ERK or JNK inhibition. Our data suggests that TGF increases VEGF production in MSCs via MEK and PI-3 K, but not ERK or JNK, dependent mechanisms.