RESUMO
Reelin is a secreted glycoprotein important for brain development and synaptic plasticity in the adult brain. Some reports suggest that Reelin is secreted from the nerve terminals and functions as a neurotransmitter. However, the mechanism of Reelin secretion is unknown. In this study, we visualized Reelin secretion by bioluminescence imaging using a fusion protein of Reelin and Gaussia luciferase (GLase-Reelin). GLase-Reelin expressed in HEK293T cells was correctly processed and secreted. Luminescence signals from the secreted GLase-Reelin of primary cultured neurons were visualized by bioluminescence microscopy. Reelin secretory events were observed at neurites and cell bodies. Bioluminescence imaging was also performed before and after KCl depolarization to compare the secretory events of Reelin and brain-derived neurotrophic factor (BDNF). The secretion of BDNF increased markedly shortly after depolarization. In contrast, the frequency of Reelin secretion did not change significantly by depolarization. Thus, Reelin secretion from neurites might not be regulated in a neuronal activity-dependent manner.
Assuntos
Fator Neurotrófico Derivado do Encéfalo , Neurônios , Encéfalo/metabolismo , Fator Neurotrófico Derivado do Encéfalo/metabolismo , Moléculas de Adesão Celular Neuronais/genética , Moléculas de Adesão Celular Neuronais/metabolismo , Células Cultivadas , Proteínas da Matriz Extracelular/metabolismo , Células HEK293 , Humanos , Neuritos/metabolismo , Neurônios/metabolismoRESUMO
Neuroendocrine tumors usually develop in the gastrointestinal tract, pancreas, and lung. Therefore, a neuroendocrine tumor of the bile duct is quite rare. We present a 59-year-old-male patient whose preoperative diagnosis was hilar cholangiocarcinoma. One month after embolization of the left branch and anterior branch of the portal vein, he underwent left hepatic trisegmentectomy and extrahepatic bile duct resection. Pathological examination revealed the neuroendocrine tumor in the submucosal layer of the hilar bile duct. Because there was no neuroendocrine tumor in other organs, the tumor was considered a primary neuroendocrine tumor of the hilar bile duct, rather than a liver metastasis from other organs. We also present a review of the English literature regarding neuroendocrine tumors of the bile duct.