Pituitary adenylyl cyclase-activating polypeptide 38 reduces astroglial proliferation by inhibiting the GTPase RhoA.
Pituitary adenylyl cyclase-activating polypeptide 38 (PACAP38) plays an important role in the proliferation and differentiation of neural cells. In the present study, we have investigated how PACAP38 inhibits the proliferation of cultured neocortical astroglial cells. When applied to synchronized cells during the G(1) phase of the cell cycle, PACAP38 diminished the subsequent nuclear uptake of bromodeoxyuridine. When applied for 2 days, it reduced the cell number. PACAP38 did not exert its antiproliferative effect by activating protein kinase A. It also did not reduce the activity of mitogen-activated protein kinases essential for G(1) phase progression. Instead, PACAP38 acted on a member of the Rho family of small GTPases. It reduced the activity of RhoA as was shown with a Rhotekin pull-down assay. The decrease in endogenous RhoA activity induced by treatment of the cells with C3 exotoxin or by expression of dominant negative RhoA also reduced the nuclear uptake of bromodeoxyuridine. In contrast, expression of constitutively active RhoA prevented the effect of PACAP38. Our data show a novel signal transduction pathway by which the neuropeptide influences cell proliferation.
Meyer
Dieter K
DK
Institut für Experimentelle und Klinische Pharmakologie und Toxikologie, Zentrum für Neurowissenschaften, Albert-Ludwigs-Universität, D-79104 Freiburg, Germany. dieter.meyer@pharmakol.uni-freiburg.de
Fischer
Catharina
C
Becker
Ulrike
U
Göttsching
Isabel
I
Boutillier
Stephanie
S
Baermann
Christian
C
Schmidt
Gudula
G
Klugbauer
Norbert
N
Leemhuis
Jost
J
D000199:Actins / Q000737:chemistry; D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000166:cytology* / Q000378:metabolism; D001973:Bromodeoxyuridine / Q000494:pharmacology; D002453:Cell Cycle; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016193:G1 Phase; D020558:GTP Phosphohydrolases / Q000737:chemistry; D019204:GTP-Binding Proteins; D005799:Genes, Dominant; D005982:Glutathione Transferase / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry; D020935:MAP Kinase Signaling System; D008856:Microscopy, Fluorescence; D009414:Nerve Growth Factors / Q000378:metabolism / Q000502:physiology*; D009479:Neuropeptides / Q000378:metabolism / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000378:metabolism / Q000502:physiology*; D010455:Peptides / Q000737:chemistry; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D013752:Tetracycline / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
D000199:Actins; C495403:Adcyap1 protein, rat; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D009414:Nerve Growth Factors; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D010455:Peptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D012333:RNA, Messenger; C498396:Rtkn protein, rat; D049452:Green Fluorescent Proteins; D005982:Glutathione Transferase; D017868:Cyclic AMP-Dependent Protein Kinases; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D013752:Tetracycline; D001973:Bromodeoxyuridine