Pituitary adenylate cyclase-activating polypeptide triggers dual transduction signaling in CATH.a cells and transcriptionally activates tyrosine hydroxylase and c-fos expression.
We used a catecholaminergic neuron-like cell line (CATH.a cells) as a model system to investigate the likelihood that pituitary adenylate cyclase-activating polypeptide (PACAP) may participate in the regulation of specific gene expression in catecholaminergic neurons. Analysis by reverse transcriptase-PCR amplification revealed the presence in these cells of type I PACAP receptors, with a short isoform, together with a heavier so-called Hop splice variant. PACAP38 and PACAP27 enhanced, in a dose-dependent manner, both cyclic AMP formation and phosphoinositide breakdown, with EC50 values of, respectively, 0.6 x 10(-10) and 2 x 10(-9) M. These peptides, in addition, also elevated [Ca2+]i by mobilizing intracellular calcium pools. Vasoactive intestinal peptide (VIP) was approximately 1,000-fold less potent in stimulating cyclic AMP (with EC50 = 2 x 10(-7) M) and failed to change the turnover of phosphoinositides and to alter [Ca2+]i. Both forms of PACAP, as well as forskolin, stimulated transcriptional induction of tyrosine hydroxylase (TH) and c-fos promoters fused to a chloramphenicol acetyltransferase (CAT) reporter gene in transiently transfected cells (p < 0.01 vs. controls). Induction of CAT activity linked to both TH and c-fos promoters was obliterated upon coexpression of a dominant inhibitory mutant (Mt-RAB) of cyclic AMP-dependent protein kinase. We conclude that CATH.a cells do express functional PACAP type I receptors, the activation of which impinges on TH and c-fos transcription according to a process that is primarily dependent on the cyclic AMP-PKA pathway.
Muller
A
A
IPCB, Laboratoire de Neurophysiologie et de Neurobiologie des Systèmes Endocrines, URA CNRS 1446, Paris, France.
Monnier
D
D
Rene
F
F
Larmet
Y
Y
Koch
B
B
Loeffler
J P
JP
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002460:Cell Line / Q000737:chemistry / Q000201:enzymology; D015500:Chloramphenicol O-Acetyltransferase; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000502:physiology; D017930:Genes, Reporter; D007295:Inositol Phosphates / Q000378:metabolism; D007536:Isomerism; D009474:Neurons / Q000737:chemistry / Q000166:cytology / Q000201:enzymology; D009479:Neuropeptides / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D010902:Pituitary Gland / Q000166:cytology*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D051381:Rats; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone / Q000737:chemistry; D015398:Signal Transduction / Q000502:physiology*; D013997:Time Factors; D014158:Transcription, Genetic / Q000502:physiology; D014162:Transfection; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
C495403:Adcyap1 protein, rat; D007295:Inositol Phosphates; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D010726:Phosphodiesterase Inhibitors; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D016760:Proto-Oncogene Proteins c-fos; D051236:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I; D011979:Receptors, Pituitary Hormone; D014660:Vasoactive Intestinal Peptide; D014446:Tyrosine 3-Monooxygenase; D015500:Chloramphenicol O-Acetyltransferase; D000262:Adenylyl Cyclases; D002118:Calcium