Effect of ammonia, glutamine, and serum on calcineurin, p38MAPK-diP, GADD153/CHOP10, and CNTF in primary rat astrocyte cultures.
Primary astrocyte cultures were subjected to different experimental schedules using several concentrations of ammonia (1, 3, and 5 mM ammonium chloride), serum (2.5%, 5%, and 12%), and glutamine (0.5, 1, and 3 mM) to analyze the involvement of calcineurin (CaN) in hyperammonemia and its relation with p38MAPK-diP and ciliary neurotrophic factor (CNTF). We demonstrated that exposure to ammonia affects CaN content, and confirmed the ammonia-induced reduction of CNTF expression; however, the involvement of CaN and p38MAPK-diP in CNTF reduction could not be confirmed. On the contrary, an inverse relationship between CaN and p38MAPK-diP contents was clearly demonstrated. GADD153/CHOP10 content was always higher under hyperammonemic conditions as well as under glutamine exposure, probably due to the osmotic stress provoked by glutamine accumulation, which was induced after exposure to ammonia. Statistical analysis demonstrated significant interactions of ammonia and serum for CaN, GADD153/CHOP10 and CNTF contents. The exposure to glutamine also induced changes in GADD153/CHOP10 and CaN; however, CNTF content was not affected. In conclusion, CaN content was affected by exposure to ammonia and glutamine; the serum content of the culture medium had a strong influence on the astroglial response to ammonium chloride, and glutamine exposure only reproduced some of the ammonia effects.
Bodega
Guillermo
G
Departamento de Biología Celular y Genética, Facultad de Biología, Universidad de Alcalá, E-28871 Alcalá de Henares, Madrid, Spain. guillermo.bodega@uah.es
Suárez
Isabel
I
Paniagua
Carlos
C
Vacas
Enrique
E
Fernández
Benjamín
B
D000641:Ammonia / Q000378:metabolism* / Q000633:toxicity; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D001798:Blood Proteins / Q000494:pharmacology; D001921:Brain / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology*; D019703:Calcineurin / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D020934:Ciliary Neurotrophic Factor / Q000187:drug effects / Q000378:metabolism; D003470:Culture Media / Q000494:pharmacology; D005973:Glutamine / Q000378:metabolism* / Q000633:toxicity; D006501:Hepatic Encephalopathy / Q000378:metabolism / Q000503:physiopathology; D022124:Hyperammonemia / Q000378:metabolism / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D051742:Transcription Factor CHOP / Q000187:drug effects / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000187:drug effects / Q000378:metabolism
D001798:Blood Proteins; D020934:Ciliary Neurotrophic Factor; D003470:Culture Media; C497251:Ddit3 protein, rat; D005973:Glutamine; D051742:Transcription Factor CHOP; D000641:Ammonia; D048051:p38 Mitogen-Activated Protein Kinases; D019703:Calcineurin