Increased Expression of Phosphorylated c-Jun Amino-terminal Kinase and Phosphorylated c-Jun in Human Cerebral Aneurysms: Role of the c-Jun Amino-terminal Kinase/c-Jun Pathway in Apoptosis of Vascular Walls

Abstract OBJECTIVE Vascular remodeling via apoptotic mechanisms is an important factor in vascular diseases. c-Jun amino-terminal kinase (JNK) is a member of the mitogen-activated protein kinase family and initiates apoptosis mainly via phosphorylation of the c-Jun transcription factor. We performed this study to clarify the roles of the JNK/c-Jun pathway and apoptosis in the pathogenesis of cerebral aneurysms. METHODS Cerebral aneurysms from 12 patients and control vessels from 5 patients were studied. We analyzed the expression of phosphorylated JNK and phosphorylated c-Jun in cerebral aneurysms by using immunohistochemical methods. RESULTS Immunoreactivity for phosphorylated JNK and phosphorylated c-Jun was increased in the vascular walls of the cerebral aneurysms studied. Immunoreactivity for single-stranded deoxyribonucleic acid (a marker of deoxyribonucleic acid damage) was also increased in aneurysmal tissue, compared with control vessels, and was colocalized with that for phosphorylated JNK and phosphorylated c-Jun in smooth muscle cells. CONCLUSION These observations may lead to better understanding of the role of the JNK/c-Jun pathway in the development of cerebral aneurysms and to new strategies for treatment.