Tazi KA, Quioc JJ, Saada V, Bezeaud A, Lebrec D, Moreau R. Upregulation of TNF-alpha production signaling pathways in monocytes from patients with advanced cirrhosis: possible role of Akt and IRAK-M.
J Hepatol 2006;
45:280-9. [PMID:
16635535 DOI:
10.1016/j.jhep.2006.02.013]
[Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Revised: 01/31/2006] [Accepted: 02/08/2006] [Indexed: 12/16/2022]
Abstract
BACKGROUND/AIMS
In cirrhosis, tumor necrosis factor (TNF)-alpha overproduction is involved in both the systemic complications and progression of liver injury. Since monocytes from patients with advanced cirrhosis have an increase in lipopolysaccharide (LPS)-induced TNF-alpha production, we hypothesized that an upregulation of TNF-alpha production pathways and/or alteration of constitutive and inducible suppressor of TNF-alpha hyperproduction (protein kinase B (Akt) and interleukin-1 receptor-associated kinase (IRAK)-M, respectively) should be found in monocytes of these patients. Thus, we investigated ex vivo the signaling pathways of TNF-alpha production before and after LPS incubation in monocytes from noninfected Child-Pugh C patients with advanced cirrhosis and healthy subjects.
METHODS
TNF-alpha production, expressions of intracellular TNF-alpha, toll-like receptor-4 (TLR4), IkappaB-alpha, IRAK-1, IRAK-M, mitogen-activated protein (MAP) kinases and Akt activity were measured in monocytes.
RESULTS
Cirrhotic monocytes without LPS have less TLR4 expression, less IkappaB-alpha protein levels, more TNF-alpha expression, higher MAP kinase activities and decreased Akt activity than control monocytes. In cirrhotic monocytes, LPS-induced TNF-alpha hyperproduction and signaling upregulation were associated with a lack of IRAK-M induction.
CONCLUSIONS
Upregulated signaling pathways of the TNF-alpha production, decreased Akt activity and a lack of IRAK-M induction may be involved in the process of cirrhotic monocyte sensitization to produce TNF-alpha.
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