A study for the mechanism of two-facedness of NFκB

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 10670580
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Neurology
• Research Institution: FUKUI MEDICAL UNIVERSITY
• Principal Investigator: FUJIYAMA Jiro Fukui Medical University, University hospital, Assistant, 医学部・附属病院, 助手 (40283171)
• Co-Investigator(Kenkyū-buntansha): KURIYAMA Masaru Fukui Medical University, University hospital, Lecturer, 医学部, 教授 (80107870) ; MUTOH Tatsuro Fukui Medical University, Medical Department, Professor, 医学部・附属病院, 講師 (60190857)
• Project Period (FY): 1998 – 1999
• Keywords: nitric oxide (NO) / inducible nitric oxide synthase (iNOS) / astrocytes / thrombin / sphyngosine / NFκ-B

Research Abstract

It is known the significance of activation of inducible nitric oxide synthase (iNOS) through NFκ-B in some neurological diseases, such as Alzheimer's disease. As NFκ-B has many actions, it is very important to clarify the mechanism of two- facedness of NFκB. Thrombin is one of increased materials in the brain of Alzheimer's disease. We found that crude thrombin, but not plasminogen-free thrombin, induced nitric oxide (NO) on rat fetal astrocytes. Plasminogen, which contaminated in crude thrombin, induced NO cooper at ed with Interferon-γ(IF-γ). On the other hand, amyroid β protein did not influence the expression of thrombin mRNA. Here, sphyngomyelin pathway has the possibility that activates NFκ-B and induces iNOS expression. C2-ceramide only or combination with IF-γ did not affect, but neutral sphyngomyelinase or sphyngosine induced NO production with IF-γ. Fumonicin-B1, which increases the intrinsic sphingosine, enhanced NO production by TNF-α and IF-γ, or IL-1β and IF-γ. So, we considered sphingosine is important in sphyngomyerin pathway on NO-production. Using gel shift assay, we shown that TNF-α or TNF-α+ IF-γ strongly activated NFκ-B, and that IF-γ only, thrombin only, or combination with both mildly activated NFκ-B. It is confirmed by super-gel shift assay, that all these activated NFκ-B is a pair of p65 and p50. As the results, the activation of NFκ-B is necessary but not significant for induction of iNOS. Shingosine is also known as a inhibitor of PKC and have the potency for induction of iNOS, so we considered that induction of iNOS is need some modification after NFκ-B activation, and this modification is important for two-facedness of NFκB.