Angiogenesis is critical for the healing of gastric mucosal injury and is considered to be primarily regulated by vascular endothelial growth factor (VEGF), the fundamental pro-angiogenic factor. The role of nerve growth factor (NGF) in gastric angiogenesis is unknown. We examined: the expression of NGF and its TrkA receptor in endothelial cells (ECs) isolated from gastric mucosa of rats (GMECs); the effect of NGF treatment on in vitro angiogenesis in GMECs; and, the mechanisms underlying NGF's pro-angiogenic actions. Isolated GMECs from Fisher rats were treated with: vehicle, NGF (10-1,000 ng/ml), VEGF (20 ng/ml) or NGF+VEGF. To determine whether and to what extent NGF is critical for angiogenesis in GMECs, we silenced NGF expression using specific siRNA and examined in vitro angiogenesis with and without treatment with exogenous NGF and/or VEGF. Treatment of GMECs with NGF significantly increased in vitro angiogenesis similar to that seen in GMECs treated with VEGF. Silencing of NGF in GMECs abolished angiogenesis and this effect was reversed only by exogenous NGF but not VEGF, which indicates a direct pro-angiogenic action of NGF on GMECs that is at least in part distinct and independent of VEGF. NGF's pro-angiogenic action on GMECs was mediated via PI3 K/Akt signaling. This study showed for the first time that gastric mucosal ECs express NGF and its receptor TrkA, and that NGF is critical for angiogenesis in these cells.
- endothelial cells
- nerve growth factor
- PI3 Kinase
- Copyright © 2016, American Journal of Physiology-Gastrointestinal and Liver Physiology