title: Up-regulation of the PACAP type-1 receptor (PAC1) promoter by neurotrophins in rat PC12 cells and mouse cerebellar granule cells via the Ras/mitogen-activated protein kinase cascade.
abstract: The pituitary adenylate cyclase-activating polypeptide type-1 receptor (PAC1) has been involved in the survival and differentiation of neuroblasts during development. This study examined the effects of various neurotrophins on the activity of the mouse PAC1 promoter/luciferase reporter constructs in rat PC12 cells and in 8-day-old mouse cerebellar granule cells. In PC12 cells, both differentiating factors such as nerve growth factor (NGF) and mitogens such as epidermal growth factor (EGF) and insulin growth factor-1 (IGF-1) up-regulated PAC1 promoter activity by 2-4-fold in a concentration-dependent manner. Although PACAP differentiated the PC12 cells, it had no effect on the PAC1 promoter and antagonized the stimulatory effect of NGF. In cerebellar granule cells, IGF-1 and brain-derived neurotrophic factor (BDNF) also stimulated the activity of the PAC1 promoter. NGF and IGF-1 increased endogenous PAC1 mRNA levels, and the NGF-induced up-regulation is the result of an increase in transcription from PAC1 promoter instead of an increase in mRNA stability. The mitogen-activated protein kinase (MAPK) kinase inhibitor, PD98059, prevented the transcriptional effects both in PC12 and cerebellar granule cells. Moreover, expression of dominant-negative Ras protein in PC12 cells also prevented the NGF effect. Our results show that the PAC1 promoter can be up-regulated by diverse neurotrophins via an MAPK-dependent pathway and suggest a role for the Ras protein.
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D020932:Nerve Growth Factor / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009479:Neuropeptides / Q000494:pharmacology; D016716:PC12 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011401:Promoter Regions, Genetic / Q000187:drug effects* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D015854:Up-Regulation / Q000187:drug effects; D018631:ras Proteins / Q000378:metabolism*
chemical_list: C495402:Adcyap1 protein, mouse; C495403:Adcyap1 protein, rat; C495504:Adcyap1r1 protein, mouse; C495505:Adcyap1r1 protein, rat; D019208:Brain-Derived Neurotrophic Factor; D009414:Nerve Growth Factors; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone; D007334:Insulin-Like Growth Factor I; D020932:Nerve Growth Factor; D019869:Phosphatidylinositol 3-Kinases; D018631:ras Proteins