RESUMO
Serine proteases play essential roles in a wide variety of cellular processes in endocrine cells. There is a growing interest in the roles of serine protease inhibitors, or serpins, as key regulators of their activity. We have cloned two neuroserpin cDNAs from a rat pituitary cDNA library and confirmed tissue plasminogen activator as a potential target for this inhibitor. We show that neuroserpin transcripts are expressed by endocrine cells in the adrenal and pituitary glands and that immunoreactive neuroserpin is stored in densely cored secretory granules in these cells. Overexpression of neuroserpin in an anterior pituitary corticotroph cell line results in the extension of neurite-like processes, suggesting that neuroserpin may play a role in cell communication, cell adhesion, and/or cell migration.
Assuntos
Neuropeptídeos/biossíntese , Neuropeptídeos/fisiologia , Hipófise/citologia , Serpinas/biossíntese , Serpinas/fisiologia , Glândulas Suprarrenais/citologia , Sequência de Aminoácidos , Animais , Adesão Celular , Comunicação Celular , Linhagem Celular , Movimento Celular , Clonagem Molecular , DNA Complementar/metabolismo , Biblioteca Gênica , Hibridização In Situ , Dados de Sequência Molecular , Neuropeptídeos/química , Neuropeptídeos/genética , Ratos , Homologia de Sequência de Aminoácidos , Serpinas/química , Serpinas/genética , NeuroserpinaRESUMO
Neuroserpin is a serine protease inhibitor widely expressed in the developing and adult nervous systems and implicated in the regulation of proteases involved in processes such as synaptic plasticity, neuronal migration and axogenesis. We have analysed the effect of neuroserpin on growth factor-induced neurite outgrowth in PC12 cells. We show that small changes in neuroserpin expression result in changes to the number of cells extending neurites and total neurite length following NGF treatment. Increased expression of neuroserpin resulted in a decrease in the number of cells extending neurites and a reduction in total free neurite length whereas reduced levels of neuroserpin led to a small increase in the number of neurite extending cells and a significant increase in total free neurite length compared to the parent cell line. Neuroserpin also altered the response of PC12 cells to bFGF and EGF treatment. Neuroserpin was localised to dense cored secretory vesicles in PC12 cells but was unable to complex with its likely enzyme target, tissue plasminogen activator at the acidic pH found in these vesicles. These data suggest that modulation of neuroserpin levels at the extending neurite growth cone may play an important role in regulating axonal growth.
