2003 Fiscal Year Final Research Report Summary
Evaluation of Gs protein regulation in septic heart of gene deficiency mice
| Project/Area Number |
13470316
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | Hokkaido University |
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Principal Investigator |
GANDO Satoshi Hokkaido Univ., Grad. School of Med., Prof., 大学院・医学研究科, 教授 (30125306)
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| Co-Investigator(Kenkyū-buntansha) |
HATTORI Yuichi Hokkaido Univ., Grad. School of Med., Asso. Prof., 大学院・医学研究科, 助教授 (50156361)
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| Project Period (FY) |
2001 – 2003
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| Keywords | sepsis / heart / Gs-α / nuclear factor-κB / gene therapy / knockout mice |
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| Research Abstract |
Sepsis can cause a direct change of intracellular signaling in the heart, which includes reduction of positive inotropic effects by diminished Gsα proteins. The decrease of Gsα was investigated in this study by using gene targeting therapy and caecum legation and puncture (CLP) and injection of lipopolysaccharide (LPS).
Cardiac Gsα was decreased to about 45% from 36 h by death time in the CLP mice. Anti TNF-α antibody, anti IL-1β antibody, anti IL-6 antibody and iNOS selective inhibitor, FR26U330, cannot reverse the decrease of Gsα, in CLP. Some knockout mice of inflammatory cytokine, such as iNOS, showed no effects of the regulation of Gsα in sepsis. As a result of CLP mice, gene therapies of nuclear factor-xB (NF-κB) were easily uptaken in the lung and the atrium and were able to inhibit the production of inflammatory cytokines, such as iNOS. However, a gene therapy of nuclear factor -κB (NF-κB) cannot improve Gsα reduction in the heart of CLP mice. Even in septic rabbits by injection of LPS, the, diminished amounts of Gsα in the atrium were not significantly improved by NF-κB gene therapy. In this study, the regulation of Gsα and intracelluer signaling via histamine remained to be diminished in septic atrium.
Imrnunohistochemistry revealed that the expression of Toll-like receptor 4 (TLR4) appeared in the atrium, which can induce inflammatory cytokines by NF-κB activation in gel-mobility shift assay and northern blot analysis. Knockout mice of macrophage migration inhibitory factor (MTF) inhibited TLR4 expression in the atrium and significantly improved the depression of the amount of Gsα in Western blot analysis.
We conclude that sepsis cannot reduce Gsα in the heart by activation of transcriptional factor NF-κB but MAP kinase via stimulation of TLR4.
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