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Roles for protein kinases in the induction of nitric oxide synthase in astrocytes.
Glia. 1994 Jul; 11(3):227-34.GLIA

Abstract

Lipopolysaccharide (LPS) or a combination of interferon (IFN)-gamma and interleukin (IL)-1 beta can induce a calcium-independent nitric oxide synthase (iNOS) in astrocyte cultures (Simmons and Murphy: J Neurochem 59:897, 1992; Eur J Neurosci 5:825, 1993; Galea et al: Proc Natl Acad Sci USA 89:10945, 1992). This induction can be measured by assaying cyclic GMP levels in the cultures, which correlates with, but is more sensitive than, measurement of nitrite accumulation. To study potential second-messenger systems involved in the induction of iNOS, phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, and various protein kinase inhibitors were employed. PMA induced a time-, dose-, and L-arginine-dependent increase in cyclic GMP, which could be inhibited by dexamethasone or actinomycin D. This induction could be dramatically increased by concurrent treatment with IFN-gamma. The presence of iNOS mRNA could be demonstrated by hybridization with a specific cDNA probe. H7 (a non-specific serine/threonine kinase inhibitor) but not H89 (a more specific PKA inhibitor) prevented induction by all agents. However, downregulation of PKC or pretreatment with the PKC inhibitor calphostin C did not prevent the induction by LPS or cytokines, suggesting that PKC is not necessary for iNOS induction by these mediators. Additionally, genistein (a nonspecific tyrosine kinase inhibitor) could prevent induction by all agents, but the more specific inhibitor, tyrphostin, attenuated only NOS induction by LPS. These results suggest that activation of PKC can lead to, but is not necessary for, the induction of NOS in astrocytes and that there is a potential role for tyrosine kinases in NOS induction by LPS.(

ABSTRACT

TRUNCATED AT 250 WORDS)

Authors+Show Affiliations

Department of Pharmacology, University of Iowa College of Medicine, Iowa City 52242.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

7525477

Citation

Simmons, M L., and S Murphy. "Roles for Protein Kinases in the Induction of Nitric Oxide Synthase in Astrocytes." Glia, vol. 11, no. 3, 1994, pp. 227-34.
Simmons ML, Murphy S. Roles for protein kinases in the induction of nitric oxide synthase in astrocytes. Glia. 1994;11(3):227-34.
Simmons, M. L., & Murphy, S. (1994). Roles for protein kinases in the induction of nitric oxide synthase in astrocytes. Glia, 11(3), 227-34.
Simmons ML, Murphy S. Roles for Protein Kinases in the Induction of Nitric Oxide Synthase in Astrocytes. Glia. 1994;11(3):227-34. PubMed PMID: 7525477.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Roles for protein kinases in the induction of nitric oxide synthase in astrocytes. AU - Simmons,M L, AU - Murphy,S, PY - 1994/7/1/pubmed PY - 1994/7/1/medline PY - 1994/7/1/entrez SP - 227 EP - 34 JF - Glia JO - Glia VL - 11 IS - 3 N2 - Lipopolysaccharide (LPS) or a combination of interferon (IFN)-gamma and interleukin (IL)-1 beta can induce a calcium-independent nitric oxide synthase (iNOS) in astrocyte cultures (Simmons and Murphy: J Neurochem 59:897, 1992; Eur J Neurosci 5:825, 1993; Galea et al: Proc Natl Acad Sci USA 89:10945, 1992). This induction can be measured by assaying cyclic GMP levels in the cultures, which correlates with, but is more sensitive than, measurement of nitrite accumulation. To study potential second-messenger systems involved in the induction of iNOS, phorbol 12-myristate 13-acetate (PMA), a protein kinase C (PKC) activator, and various protein kinase inhibitors were employed. PMA induced a time-, dose-, and L-arginine-dependent increase in cyclic GMP, which could be inhibited by dexamethasone or actinomycin D. This induction could be dramatically increased by concurrent treatment with IFN-gamma. The presence of iNOS mRNA could be demonstrated by hybridization with a specific cDNA probe. H7 (a non-specific serine/threonine kinase inhibitor) but not H89 (a more specific PKA inhibitor) prevented induction by all agents. However, downregulation of PKC or pretreatment with the PKC inhibitor calphostin C did not prevent the induction by LPS or cytokines, suggesting that PKC is not necessary for iNOS induction by these mediators. Additionally, genistein (a nonspecific tyrosine kinase inhibitor) could prevent induction by all agents, but the more specific inhibitor, tyrphostin, attenuated only NOS induction by LPS. These results suggest that activation of PKC can lead to, but is not necessary for, the induction of NOS in astrocytes and that there is a potential role for tyrosine kinases in NOS induction by LPS.(ABSTRACT TRUNCATED AT 250 WORDS) SN - 0894-1491 UR - https://www.unboundmedicine.com/medline/citation/7525477/Roles_for_protein_kinases_in_the_induction_of_nitric_oxide_synthase_in_astrocytes_ L2 - https://doi.org/10.1002/glia.440110303 DB - PRIME DP - Unbound Medicine ER -