scholarly journals RICK Promotes Inflammation and Lethality after Gram-Negative Bacterial Infection in Mice Stimulated with Lipopolysaccharide

2009 ◽  
Vol 77 (4) ◽  
pp. 1569-1578 ◽  
Author(s):  
Jong-Hwan Park ◽  
Yun-Gi Kim ◽  
Gabriel Núñez

ABSTRACT RICK (receptor-interacting protein-like interacting caspase-like apoptosis regulatory protein kinase), a serine-threonine kinase, functions downstream of the pattern recognition receptors Nod1 and Nod2 to mediate NF-κB and mitogen-activated protein kinase (MAPK) activation in response to specific microbial stimuli. However, the function of RICK in the recognition and host defense of gram-negative bacteria remains poorly understood. We report here that infection of wild-type and RICK-deficient macrophages with Pseudomonas aeruginosa and Escherichia coli elicited comparable activation of NF-κB and MAPKs as well as secretion of proinflammatory cytokines. However, production of interleukin 6 (IL-6) and IL-1β induced by these gram-negative bacteria was impaired in RICK-deficient macrophages when the cells had previously been stimulated with lipopolysaccharide (LPS) or E. coli. The diminished proinflammatory response of RICK-deficient macrophages to bacteria was associated with reduced activation of NF-κB and MAPKs. Importantly, mutant mice deficient in RICK were less susceptible than wild-type mice to P. aeruginosa infection when the animals had previously been stimulated with LPS. The reduced lethality of RICK-deficient mice infected with P. aeruginosa was independent of pathogen clearance but was associated with diminished production of proinflammatory molecules in vivo. These results demonstrate that RICK contributes to the induction of proinflammatory responses and susceptibility to gram-negative bacteria after exposure to LPS, a condition that is associated with reduced Toll-like receptor signaling.

2008 ◽  
Vol 411 (3) ◽  
pp. 613-622 ◽  
Author(s):  
Maria Perander ◽  
Espen Åberg ◽  
Bjarne Johansen ◽  
Bo Dreyer ◽  
Ingrid J. Guldvik ◽  
...  

ERK (extracellular-signal-regulated kinase) 4 [MAPK (mitogen-activated protein kinase) 4] and ERK3 (MAPK6) are atypical MAPKs. One major difference between these proteins and the classical MAPKs is substitution of the conserved T-X-Y motif within the activation loop by a single phospho-acceptor site within an S-E-G motif. In the present study we report that Ser186 of the S-E-G motif in ERK4 is phosphorylated in vivo. Kinase-dead ERK4 is also phosphorylated on Ser186, indicating that an ERK4 kinase, rather than autophosphorylation, is responsible. Co-expression of MK5 [MAPK-activated protein kinase 5; also known as PRAK (p38-regulated/activated kinase)], a physiological target of ERK4, increases phosphorylation of Ser186. This is not dependent on MK5 activity, but does require interaction between ERK4 and MK5 suggesting that MK5 binding either prevents ERK4 dephosphorylation or facilitates ERK4 kinase activity. ERK4 mutants in which Ser186 is replaced with either an alanine residue or a phospho-mimetic residue (glutamate) are unable to activate MK5 and Ser186 is also required for cytoplasmic anchoring of MK5. Both defects seem to reflect an impaired ability of the ERK4 mutants to interact with MK5. We find that there are at least two endogenous pools of wild-type ERK4. One form exhibits reduced mobility when analysed using SDS/PAGE. This is due to MK5-dependent phosphorylation and only this retarded ERK4 species is both phosphorylated on Ser186 and co-immunoprecipitates with wild-type MK5. We conclude that binding between ERK4 and MK5 facilitates phosphorylation of Ser186 and stabilization of the ERK4–MK5 complex. This results in phosphorylation and activation of MK5, which in turn phosphorylates ERK4 on sites other than Ser186 resulting in the observed mobility shift.


2008 ◽  
Vol 294 (4) ◽  
pp. H1621-H1629 ◽  
Author(s):  
Thomas J. Calvert ◽  
Louis G. Chicoine ◽  
Yusen Liu ◽  
Leif D. Nelin

Mitogen-activated protein kinase phosphatase-1 (MKP-1) is essential in limiting the proinflammatory response to lipopolysaccharide (LPS). We hypothesized that Mkp-1−/− mice would respond to low-dose LPS with a fall in blood pressure due to augmented expression of inducible nitric oxide (NO) synthase (iNOS). To test this hypothesis, Mkp-1−/− mice and their wild-type littermates were treated with 10 μg/kg iv LPS, and mean arterial blood pressure (MAP) and exhaled NO production (exNO) were measured. Tissues were harvested for an assessment of iNOS protein levels. Wild-type mice had no change in MAP or exNO during the experimental period, whereas Mkp-1−/− mice had a fall ( P < 0.005) in MAP [79 ± 5% of baseline (BL)] and an increase ( P < 0.01) in exNO (266 ± 50% of BL) after 150 min. The tissue levels of iNOS were greater in Mkp-1−/− than in wild-type mice. In additional experiments, 60 min after LPS treatment, Mkp-1−/− and wild-type mice were given Nω-nitro-l-arginine methyl ester (l-NAME) or aminoguanidine, and MAP and exNO were monitored for 90 min. Treatment with l-NAME prevented the LPS-induced increase in exNO and decrease in MAP but resulted in decreased exNO and elevated MAP in wild-type mice. Aminoguanidine prevented the increase in exNO and the fall in MAP caused by LPS in Mkp-1−/− mice, without significantly affecting MAP or exNO in wild-type mice. These results demonstrate that a deficiency of MKP-1 results in an exaggerated hypotensive response to LPS mediated by augmented iNOS expression. We speculate that defects in the Mkp-1 gene may increase susceptibility for the development of septic shock.


2005 ◽  
Vol 201 (3) ◽  
pp. 409-418 ◽  
Author(s):  
Lixin Liu ◽  
Denise C. Cara ◽  
Jaswinder Kaur ◽  
Eko Raharjo ◽  
Sarah C. Mullaly ◽  
...  

Leukocyte-specific protein 1 (LSP1), an F-actin binding protein and a major downstream substrate of p38 mitogen-activated protein kinase as well as protein kinase C, has been reported to be important in leukocyte chemotaxis. Although its distribution has been thought to be restricted to leukocytes, herein we report that LSP1 is expressed in endothelium and is essential to permit neutrophil emigration. Using intravital microscopy to directly visualize leukocyte rolling, adhesion, and emigration in postcapillary venules in LSP1-deficient (Lsp1−/−) mice, we found that LSP1 deficiency inhibits neutrophil extravasation in response to various cytokines (tumor necrosis factor-α and interleukin-1β) and to neutrophil chemokine keratinocyte-derived chemokine in vivo. LSP1 deficiency did not affect leukocyte rolling or adhesion. Generation of Lsp1−/− chimeric mice using bone marrow transplantation revealed that in mice with Lsp1−/− endothelial cells and wild-type leukocytes, neutrophil transendothelial migration out of postcapillary venules is markedly restricted. In contrast, Lsp1−/− neutrophils in wild-type mice were able to extravasate normally. Consistent with altered endothelial function was a reduction in vascular permeability to histamine in Lsp1−/− animals. Western blot analysis and immunofluorescence microscopy examination confirmed the presence of LSP1 in wild-type but not in Lsp1−/− mouse microvascular endothelial cells. Cultured human endothelial cells also stained positive for LSP1. Our results suggest that LSP1 expressed in endothelium regulates neutrophil transendothelial migration.


2004 ◽  
Vol 72 (10) ◽  
pp. 5662-5667 ◽  
Author(s):  
Nicola J. Mason ◽  
Jim Fiore ◽  
Takashi Kobayashi ◽  
Katherine S. Masek ◽  
Yongwon Choi ◽  
...  

ABSTRACT The production of interleukin-12 (IL-12) is critical to the development of innate and adaptive immune responses required for the control of intracellular pathogens. Many microbial products signal through Toll-like receptors (TLR) and activate NF-κB family members that are required for the production of IL-12. Recent studies suggest that components of the TLR pathway are required for the production of IL-12 in response to the parasite Toxoplasma gondii; however, the production of IL-12 in response to this parasite is independent of NF-κB activation. The adaptor molecule TRAF6 is involved in TLR signaling pathways and associates with serine/threonine kinases involved in the activation of both NF-κB and mitogen-activated protein kinase (MAPK). To elucidate the intracellular signaling pathways involved in the production of IL-12 in response to soluble toxoplasma antigen (STAg), wild-type and TRAF6−/− mice were inoculated with STAg, and the production of IL-12(p40) was determined. TRAF6−/− mice failed to produce IL-12(p40) in response to STAg, and TRAF6−/− macrophages stimulated with STAg also failed to produce IL-12(p40). Studies using Western blot analysis of wild-type and TRAF6−/− macrophages revealed that stimulation with STAg resulted in the rapid TRAF6-dependent phosphorylation of p38 and extracellular signal-related kinase, which differentially regulated the production of IL-12(p40). The studies presented here demonstrate for the first time that the production of IL-12(p40) in response to toxoplasma is dependent upon TRAF6 and p38 MAPK.


2013 ◽  
Vol 111 (3) ◽  
pp. 452-464 ◽  
Author(s):  
Gina Cecilia Pistol ◽  
Mihail Alexandru Gras ◽  
Daniela Eliza Marin ◽  
Florentina Israel-Roming ◽  
Mariana Stancu ◽  
...  

Zearalenone (ZEA) is an oestrogenic mycotoxin produced byFusariumspecies, considered to be a risk factor from both public health and agricultural perspectives. In the presentin vivostudy, a feeding trial was conducted to evaluate thein vivoeffect of a ZEA-contaminated diet on immune response in young pigs. The effect of ZEA on pro-inflammatory (TNF-α, IL-8, IL-6, IL-1β and interferon-γ) and anti-inflammatory (IL-10 and IL-4) cytokines and other molecules involved in inflammatory processes (matrix metalloproteinases (MMP)/tissue inhibitors of matrix metalloproteinases (TIMP), nuclear receptors: PPARγ and NF-κB1, mitogen-activated protein kinases (MAPK): mitogen-activated protein kinase kinase kinase 7 (TAK1)/mitogen-activated protein kinase 14 (p38α)/mitogen-activated protein kinase 8 (JNK1)/ mitogen-activated protein kinase 9 (JNK2)) in the liver of piglets was investigated. The present results showed that a concentration of 316 parts per billion ZEA leads to a significant decrease in the levels of pro- and anti-inflammatory cytokines at both gene expression and protein levels, correlated with a decrease in the levels of other inflammatory mediators, MMP and TIMP. The results also showed that dietary ZEA induces a dramatic reduction in the expressions ofNF-κB1andTAK1/p38αMAPK genes in the liver of the experimentally intoxicated piglets, and has no effect on the expression ofPPARγmRNA. The present results suggest that the toxic action of ZEA begins in the upstream of the MAPK signalling pathway by the inhibition of TAK1, a MAPK/NF-κB activator. In conclusion, the present study shows that ZEA alters several important parameters of the hepatic cellular immune response. From an economic point of view, these data suggest that, in pigs, ZEA is not only a powerful oestrogenic mycotoxin but also a potential hepatotoxin when administered through the oral route. Therefore, the present results represent additional data from cellular and molecular levels that could be taken into account in the determination of the regulation limit of the tolerance to ZEA.


Reproduction ◽  
2006 ◽  
Vol 131 (4) ◽  
pp. 711-719 ◽  
Author(s):  
Munkhuu Bayarsaikhan ◽  
Akiko Shiratsuchi ◽  
Davaakhuu Gantulga ◽  
Yoshinobu Nakanishi ◽  
Katsuji Yoshioka

Scaffold proteins of mitogen-activated protein kinase (MAPK) intracellular signal transduction pathways mediate the efficient and specific activation of the relevant MAPK signaling modules. Previously, our group and others have identified c-Jun NH2-terminal kinase (JNK)/stress-activated protein kinase-associated protein 1 (JSAP1, also known as JNK-interacting protein 3) as a scaffold protein for JNK MAPK pathways. Although JSAP1 is expressed in the testis in adults, its expression during development has not been investigated. In addition, it is unknown which types of cells in the testis express the scaffold protein. Here, we examined the expression of JSAP1 in the testis of mice aged 14 days, 20 days, 6 weeks, and 12 weeks by immunohistochemistry and Western blotting. The specificity of the anti-JSAP1 antibody was evaluated from its reactivity to exogenously expressed JSAP1 and a structurally related protein, and by antigen-absorption experiments. The immunohistochemical analyses with the specific antibody showed that the JSAP1 protein was selectively expressed in the spermatogonia and spermatocytes, but not in other cell types, including spermatids and somatic cells, during development. However, not all spermatogonia and spermatocytes were immunopositive either, especially in the 12-week-old mouse testis. Furthermore, we found by Western blotting that the expression levels of JSAP1 protein vary during development; there is high expression until 6 weeks after birth, which approximately corresponds to the end of the first wave of spermatogenesis. Collectively, these results suggest that JSAP1 function may be important in spermatogenic cells during early postnatal development.


2009 ◽  
Vol 181 (4) ◽  
pp. 659
Author(s):  
Lakshmipathi Khandrika ◽  
Binod Kumar ◽  
Sweaty Koul ◽  
Randall B Meacham ◽  
Hari K Koul

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