Histamine induces vascular endothelial cell proliferation via the histamine H1 receptor–extracellular regulated protein kinase 1/2–cyclin D1/cyclin-dependent kinase 4/6 axis

Histamine is a biogenic amine that plays important roles in the inflammatory phase of physiological wound healing and proliferation of normal and tumor cells. Stimulation of the histamine H1 receptor induces vascular endothelial cell proliferation, possibly contributing to angiogenesis during wound healing and cancer development. However, the specific signaling pathways involved in angiogenesis remain unclear. Based on our previous report that histamine induces endothelial cell tube formation by increasing the vascular endothelial growth factor and matrix metalloproteinase levels via the H1 receptor, we aimed to further examine histamine-induced cell proliferation using EA.hy926 vascular endothelial cells in this study. Histamine phosphorylated extracellular regulated protein kinase-1/2 through the protein kinase C pathway via the H1 receptor and increased c-Fos expression via phosphorylation of Elk-1 and CRE-binding protein. Moreover, c-Fos formed activator protein-1, which further upregulated cyclin D1 expression. Cyclin D1 formed a complex with cyclin-dependent kinase-4/6 and phosphorylated Rb, causing the transcription factor E2F, which is bound to Rb, to dissociate from Rb and induce the factors important for S phase initiation that advance the cell cycle. Overall, our findings in this study to identify H1 receptor-mediated cell proliferation signals in endothelial cells using histamine can aid in the development of new strategies for wound healing and cancer treatment.