S100B-RAGE-mediated augmentation of angiotensin II-induced activation of JAK2 in vascular smooth muscle cells is dependent on PLD2.

Angiotensin II (Ang II), a vasoactive peptide that is also considered a growth factor, has been implicated in both normal and diabetic cellular proliferation. We recently found that activation of janus kinase 2 (JAK2) is essential for the Ang II-induced proliferation of vascular smooth muscle cells (VSMCs) and that high glucose augments Ang II-induced proliferation of VSMCs by increasing signal transduction through activation of JAK2. Here, we demonstrate that S100B, a ligand for the receptor of advanced glycation end products (RAGEs), augmented both Ang II-induced tyrosine phosphorylation of JAK2 and cell proliferation in VSMCs in a receptor-dependent manner. We also found that S100B-RAGE interaction triggered intracellular generation of reactive oxygen species (ROS), VSMC proliferation, and JAK2 tyrosine phosphorylation via activation of phospholipase D (PLD)2. These results provide direct evidence for linkages between PLD2, ROS production, and S100B-RAGE-induced enhancement of Ang II-induced cell proliferation and activation of JAK2 in VSMCs.