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Signalling pathways regulating inducible nitric oxide synthase expression in human kidney epithelial cells
Mirjana Poljakovic1, Jens M Nygren, Katarina Persson
1Department of Clinical Pharmacology, Lund University Hospital, Lund, Sweden.
European Journal of Pharmacology
|June 5, 2003
Summary
Cytokine stimulation activates inducible nitric oxide synthase (iNOS) in kidney cells via JAK2, PKC, p38 MAPK, and NF-kappa B pathways. This study identifies key signaling molecules in the iNOS response.
Area of Science:
- Cell Biology
- Immunology
- Renal Physiology
Background:
- Inducible nitric oxide synthase (iNOS) plays a critical role in inflammatory responses within the kidney.
- Understanding the signaling pathways regulating iNOS expression is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the specific signaling pathways mediating cytokine-induced iNOS expression in human kidney epithelial cells (A498).
Main Methods:
- Cells were stimulated with a cytokine mixture (interferon gamma, interleukin-1 beta, TNF-alpha).
- Pharmacological inhibitors were used to block specific kinases (JAK2, PKC, p38 MAPK, ERK) and NF-kappa B.
- Nitrite production, iNOS mRNA, and protein expression were measured.
- Electrophoretic mobility shift assay (EMSA) was employed to assess NF-kappa B binding activity.
Main Results:
- Cytokine stimulation significantly increased nitrite production and iNOS expression.
- Inhibition of JAK2, PKC, and p38 MAPK attenuated cytokine-mediated iNOS induction.
- NF-kappa B activation was observed, and its inhibition reduced iNOS expression and nitrite production.
Conclusions:
- Cytokine-induced iNOS expression in human kidney epithelial cells is regulated by a complex signaling network.
- Key pathways involved include tyrosine kinases (JAK2), protein kinase C (PKC), p38 MAPK, and nuclear factor kappa B (NF-kappa B).