The cyclic GMP-protein kinase G pathway regulates cytoskeleton dynamics and motility in astrocytes.
We have previously demonstrated that inflammatory compounds that increase nitric oxide (NO) synthase expression have a biphasic effect on the level of the NO messenger cGMP in astrocytes. In this work, we demonstrate that NO-dependent cGMP formation is involved in the morphological change induced by lipopolysaccharide (LPS) in cultured rat cerebellar astroglia. In agreement with this, dibutyryl-cGMP, a permeable cGMP analogue, and atrial natriuretic peptide, a ligand for particulate guanylyl cyclase, are both able to induce process elongation and branching in astrocytes resulting from a rapid, reversible and concentration-dependent redistribution of glial fibrillary acidic protein (GFAP) and actin filaments without significant change in protein levels. These effects are also observed in astrocytes co-cultured with neurons. The cytoskeleton rearrangement induced by cGMP is prevented by the specific protein kinase G inhibitor Rp-8Br-PET-cGMPS and involves downstream inhibition of RhoA GTPase since is not observed in cells transfected with constitutively active RhoA. Furthermore, dibutyryl-cGMP prevents RhoA-membrane association, a step necessary for its interaction with effectors. Stimulation of the cGMP-protein kinase G pathway also leads to increased astrocyte migration in an in vitro scratch-wound assay resulting in accelerated wound closure, as seen in reactive gliosis following brain injury. These results indicate that cGMP-mediated pathways may regulate physio-pathologically relevant responses in astroglial cells.
Borán
Mariela Susana
MS
Instituto de Biotecnología y Biomedicina, Universidad Autónoma de Barcelona, Bellaterra, Spain.
García
Agustina
A
D000199:Actins / Q000378:metabolism; D000818:Animals; D000963:Antimetabolites; D001253:Astrocytes / Q000378:metabolism*; D009320:Atrial Natriuretic Factor / Q000378:metabolism; D015153:Blotting, Western; D001973:Bromodeoxyuridine; D003994:Bucladesine / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D017869:Cyclic GMP-Dependent Protein Kinases / Q000502:physiology*; D003599:Cytoskeleton / Q000378:metabolism*; D005456:Fluorescent Dyes; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007211:Indoles; D007249:Inflammation / Q000473:pathology; D008070:Lipopolysaccharides / Q000494:pharmacology; D009457:Neuroglia / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D010641:Phenotype; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection; D014947:Wounds and Injuries / Q000473:pathology; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
D000199:Actins; D000963:Antimetabolites; D005456:Fluorescent Dyes; D005904:Glial Fibrillary Acidic Protein; D007211:Indoles; D008070:Lipopolysaccharides; D009569:Nitric Oxide; C007293:DAPI; D003994:Bucladesine; D009320:Atrial Natriuretic Factor; D017869:Cyclic GMP-Dependent Protein Kinases; D020742:rhoA GTP-Binding Protein; D001973:Bromodeoxyuridine