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- Hasan, Zirak, et al.
(author)
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Rho-kinase regulates induction of T-cell immune dysfunction in abdominal sepsis.
- 2013
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In: Infection and Immunity. - 1098-5522. ; 81:7, s. 2499-2506
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Journal article (peer-reviewed)abstract
- T-cell dysfunction increases susceptibility to infections in patients with sepsis. In the present study, we hypothesized that Rho-kinase signaling might regulate induction of T-cell dysfunction in abdominal sepsis. Male C57BL/6 mice were treated with the specific Rho-kinase inhibitor Y-27632 (5 mg/kg) prior to cecal ligation and puncture (CLP). Spleen CD4 T-cell apoptosis, proliferation and regulatory T-cells (CD4(+)CD25(+)Foxp3(+)) were determined by flow cytometry. Formation of IFN-γ and IL-4 in the spleen and plasma levels of HMBG1 and IL-6 were quantified by use of ELISA. It was found that CLP evoked apoptosis and decreased proliferation in splenic CD4 T-cells. Inhibition of Rho-kinase activity decreased apoptosis and enhanced proliferation of CD4 T-cells in septic animals. In addition, CLP-evoked induction of regulatory T-cells in the spleen was abolished by Rho-kinase inhibition. CLP reduced the levels of IFN-γ and IL-4 in the spleen. Pretreatment with Y-27632 inhibited the sepsis-induced decrease in IFN-γ but not IL-4 formation in the spleen. CLP increased plasma levels of HMGB1 by 20-fold and IL-6 by 19-fold. Inhibition of Rho-kinase decreased this CLP-evoked increase of HMGB1, IL-6 and IL-17 levels in the plasma by more than 60%, suggesting that Rho-kinase regulates systemic inflammation in sepsis. Moreover, we observed that pretreatment with Y-27632 abolished CLP-induced bacteremia. Together, our novel findings indicate that Rho-kinase is a powerful regulator of T-cell immune dysfunction in abdominal sepsis. Thus, targeting Rho-kinase signaling might be a useful strategy to improve T-cell immunity in patients with abdominal sepsis.
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| 2. |
- Rahman, Milladur, et al.
(author)
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Platelet shedding of CD40L is regulated by matrix metalloproteinase-9 in abdominal sepsis.
- 2013
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In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 11:7, s. 1385-1398
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Journal article (peer-reviewed)abstract
- Background and objectives: Platelet-derived CD40L is known to regulate neutrophil recruitment and lung damage in sepsis. However, the mechanism regulating shedding of CD40L from activated platelets is not known. We hypothesized that matrix metalloproteinase-9 might cleave surface expressed CD40L and regulate pulmonary accumulation of neutrophils in sepsis. Methods: Abdominal sepsis was induced by cecal ligation and puncture (CLP) in wild-type and MMP-9-deficient mice. Edema formation, CXC chemokine, myeloperoxidase levels, neutrophils in the lung as well as plasma levels of CD40L and MMP-9 were quantified. Results: CLP increased plasma levels of MMP-9 but not MMP-2. The CLP-induced decrease of platelet surface CD40L and increase of soluble CD40L levels were significantly attenuated in MMP-9 gene-deficient mice. Moreover, pulmonary MPO activity and neutrophil infiltration in the alveolar space as well as edema formation and lung injury were markedly decreased in septic animals lacking MMP-9. In vitro studies revealed that inhibition of MMP-9 decreased platelet shedding of CD40L. Moreover, recombinant MMP-9 was capable of cleaving surface expressed CD40L on activated platelets. In human studies, plasma levels of MMP-9 were significantly increased in patients with septic shock compared to healthy controls although MMP-9 levels did not correlate with organ injury score. Conclusions: Our novel data propose a role of MMP-9 in regulating platelet-dependent infiltration of neutrophils and tissue damage in septic lung injury by controlling CD40L shedding from platelets. We conclude that targeting MMP-9 may be a useful strategy to limit acute lung injury in abdominal sepsis. This article is protected by copyright. All rights reserved.
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