Induction of VEGF-A expression by methylmercury is mediated by the EGFR–p38 MAPK–COX-2–PKA pathway in cultured human brain microvascular pericytes

Methylmercury is the causative organometallic compound of Minamata disease. Patho-logical changes in the cerebrum of patients are localized along the deep sulci and fissures of the cerebral cortex such as the calcarine fissure. It has been suggested that the occurrence of brain edema is important for the cerebral damage caused by methylmercury. Previously, we found that methylmercury induces vascular endothelial growth factor-A in cultured human brain microvascular pericytes, which may increase permeability of the brain microvasculature. In the present study, our findings suggest that this induction is mediated via the epidermal growth factor receptor–p38 mitogen-activated protein kinase–cyclooxyge-nase-2–protein kinase A pathway in cultured human brain microvascular pericytes. These results partly support our hypothesis that methylmercury causes neurotoxicity by activation of intracellular signaling pathways in various cell types, including neurons, macrophages, vascular endothelial cells, and pericytes.