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Genetic dissection of the cellular pathways and signaling mechanisms in modeled tumor necrosis factor-induced Crohn's-like inflammatory bowel disease.

Kontoyiannis D, Boulougouris G, Manoloukos M, Armaka M, Apostolaki M, Pizarro T, Kotlyarov A, Forster I, Flavell R, Gaestel M, Tsichlis P, Cominelli F, Kollias G - J. Exp. Med. (2002)

Bottom Line: Tissue-specific activation of the mutant TNF allele by Cre/loxP-mediated recombination indicated that either myeloid- or T cell-derived TNF can exhibit full pathogenic capacity.Interestingly, TNF-mediated intestinal pathology was exacerbated in the absence of MAPKAP kinase 2, yet strongly attenuated in a Cot/Tpl2 or JNK2 kinase-deficient genetic background.Our data establish the existence of redundant cellular pathways operating downstream of TNF in inflammatory bowel disease, and demonstrate the therapeutic potential of selective kinase blockade in TNF-mediated intestinal pathology.

View Article: PubMed Central - PubMed

Affiliation: Institute for Immunology, Biomedical Sciences Research Center "Al. Fleming," Vari 166-72, Greece. Division of Gastroenterology and Hepatology, University of Virginia Health Sciences Center, Charlottesville, VA 22906, USA.

ABSTRACT
Recent clinical evidence demonstrated the importance of tumor necrosis factor (TNF) in the development of Crohn's disease. A mouse model for this pathology has previously been established by engineering defects in the translational control of TNF mRNA (Tnf(Delta)(ARE) mouse). Here, we show that development of intestinal pathology in this model depends on Th1-like cytokines such as interleukin 12 and interferon gamma and requires the function of CD8(+) T lymphocytes. Tissue-specific activation of the mutant TNF allele by Cre/loxP-mediated recombination indicated that either myeloid- or T cell-derived TNF can exhibit full pathogenic capacity. Moreover, reciprocal bone marrow transplantation experiments using TNF receptor-deficient mice revealed that TNF signals are equally pathogenic when directed independently to either bone marrow-derived or tissue stroma cell targets. Interestingly, TNF-mediated intestinal pathology was exacerbated in the absence of MAPKAP kinase 2, yet strongly attenuated in a Cot/Tpl2 or JNK2 kinase-deficient genetic background. Our data establish the existence of redundant cellular pathways operating downstream of TNF in inflammatory bowel disease, and demonstrate the therapeutic potential of selective kinase blockade in TNF-mediated intestinal pathology.

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MK2, JNK2, and Tpl2 kinase–mediated signals in the development of TNF-mediated IBD. (A) Chronic inflammatory indices (CI) indicating the development of intestinal inflammation based on the histopathological assessment of TnfΔARE/+ mice (▿) in MK2- (▪), Jnk2- (▾), and Tpl2- (○) deficient backgrounds. (B) Representative density and histogram plots indicating the percentages of CD4+ and CD8+ T cells as well as their percentages of CD44+ marker in TnfΔARE/+ and TnfΔARE/+ Tpl2−/− splenocytes after flow immunocytometric analysis. (C–F) Representative histology of 3-mo-old (C) TnfΔARE/+ mice bred into (D) MK2-, (E) Jnk2-, or (F) Tpl2-deficient backgrounds. All paraffin sections were stained with hematoxylin and eosin. ×100.
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fig5: MK2, JNK2, and Tpl2 kinase–mediated signals in the development of TNF-mediated IBD. (A) Chronic inflammatory indices (CI) indicating the development of intestinal inflammation based on the histopathological assessment of TnfΔARE/+ mice (▿) in MK2- (▪), Jnk2- (▾), and Tpl2- (○) deficient backgrounds. (B) Representative density and histogram plots indicating the percentages of CD4+ and CD8+ T cells as well as their percentages of CD44+ marker in TnfΔARE/+ and TnfΔARE/+ Tpl2−/− splenocytes after flow immunocytometric analysis. (C–F) Representative histology of 3-mo-old (C) TnfΔARE/+ mice bred into (D) MK2-, (E) Jnk2-, or (F) Tpl2-deficient backgrounds. All paraffin sections were stained with hematoxylin and eosin. ×100.

Mentions: Contrary to its presumed requirement for the activation of proinflammatory programs, the absence of the MK2 signaling pathway resulted in the profound exacerbation of the TnfΔAREphenotype and was associated with high incidences of mortality from the age of 8 wk onwards (Fig. 5 A and unpublished data). IBD development in TnfΔARE/+ mk2−/− mice was associated with the early formation of multiple granulomas and extensive lymphocytic aggregates in the lamina propria (Fig. 5 D). In striking contrast, the absence of the JNK2 or the Tpl2 kinases resulted in a delayed onset and a significant attenuation in the development of IBD (Fig. 5, A, E, and F). In both cases, chronic intestinal inflammation (i.e., macrophage and lymphocytic exudates) was significantly reduced (Fig. 5 A). Flow immunocytometric analysis of splenocyte populations from the kinase-deficient animals at the age of 4 mo indicated that relative to control TnfΔAREpopulations, CD4+ to CD8+ lymphocyte ratios remained unaltered in MK2- and JNK2-deficient animals (not depicted) but not in Tpl2-deficient animals (Fig. 5 B). Despite the increased presence of CD11b+ and Gr1+ myeloid cells, indicating a persistent innate immune activation (not depicted), TnfΔARE/+ tpl2−/−–deficient splenocytes contained a higher content of T lymphocytes than TnfΔARE/+ controls (not depicted), but a correct CD8/CD4 ratio (Fig. 5 B). Interestingly, this difference was attributed to a significant increase in total CD4+ counts, which primarily possessed a CD44lo phenotype indicating that they are mostly accumulating in a naive state (Fig. 5 B). Most importantly, the number of CD8+ CD44hi T cells was found to be significantly reduced in TnfΔARE/+ tpl2−/− splenocytes relative to TnfΔARE/+ controls (Fig. 5 B), suggesting that the absence of Tpl2 affects the pathogenic lymphocytic responses.


Genetic dissection of the cellular pathways and signaling mechanisms in modeled tumor necrosis factor-induced Crohn's-like inflammatory bowel disease.

Kontoyiannis D, Boulougouris G, Manoloukos M, Armaka M, Apostolaki M, Pizarro T, Kotlyarov A, Forster I, Flavell R, Gaestel M, Tsichlis P, Cominelli F, Kollias G - J. Exp. Med. (2002)

MK2, JNK2, and Tpl2 kinase–mediated signals in the development of TNF-mediated IBD. (A) Chronic inflammatory indices (CI) indicating the development of intestinal inflammation based on the histopathological assessment of TnfΔARE/+ mice (▿) in MK2- (▪), Jnk2- (▾), and Tpl2- (○) deficient backgrounds. (B) Representative density and histogram plots indicating the percentages of CD4+ and CD8+ T cells as well as their percentages of CD44+ marker in TnfΔARE/+ and TnfΔARE/+ Tpl2−/− splenocytes after flow immunocytometric analysis. (C–F) Representative histology of 3-mo-old (C) TnfΔARE/+ mice bred into (D) MK2-, (E) Jnk2-, or (F) Tpl2-deficient backgrounds. All paraffin sections were stained with hematoxylin and eosin. ×100.
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Related In: Results  -  Collection

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fig5: MK2, JNK2, and Tpl2 kinase–mediated signals in the development of TNF-mediated IBD. (A) Chronic inflammatory indices (CI) indicating the development of intestinal inflammation based on the histopathological assessment of TnfΔARE/+ mice (▿) in MK2- (▪), Jnk2- (▾), and Tpl2- (○) deficient backgrounds. (B) Representative density and histogram plots indicating the percentages of CD4+ and CD8+ T cells as well as their percentages of CD44+ marker in TnfΔARE/+ and TnfΔARE/+ Tpl2−/− splenocytes after flow immunocytometric analysis. (C–F) Representative histology of 3-mo-old (C) TnfΔARE/+ mice bred into (D) MK2-, (E) Jnk2-, or (F) Tpl2-deficient backgrounds. All paraffin sections were stained with hematoxylin and eosin. ×100.
Mentions: Contrary to its presumed requirement for the activation of proinflammatory programs, the absence of the MK2 signaling pathway resulted in the profound exacerbation of the TnfΔAREphenotype and was associated with high incidences of mortality from the age of 8 wk onwards (Fig. 5 A and unpublished data). IBD development in TnfΔARE/+ mk2−/− mice was associated with the early formation of multiple granulomas and extensive lymphocytic aggregates in the lamina propria (Fig. 5 D). In striking contrast, the absence of the JNK2 or the Tpl2 kinases resulted in a delayed onset and a significant attenuation in the development of IBD (Fig. 5, A, E, and F). In both cases, chronic intestinal inflammation (i.e., macrophage and lymphocytic exudates) was significantly reduced (Fig. 5 A). Flow immunocytometric analysis of splenocyte populations from the kinase-deficient animals at the age of 4 mo indicated that relative to control TnfΔAREpopulations, CD4+ to CD8+ lymphocyte ratios remained unaltered in MK2- and JNK2-deficient animals (not depicted) but not in Tpl2-deficient animals (Fig. 5 B). Despite the increased presence of CD11b+ and Gr1+ myeloid cells, indicating a persistent innate immune activation (not depicted), TnfΔARE/+ tpl2−/−–deficient splenocytes contained a higher content of T lymphocytes than TnfΔARE/+ controls (not depicted), but a correct CD8/CD4 ratio (Fig. 5 B). Interestingly, this difference was attributed to a significant increase in total CD4+ counts, which primarily possessed a CD44lo phenotype indicating that they are mostly accumulating in a naive state (Fig. 5 B). Most importantly, the number of CD8+ CD44hi T cells was found to be significantly reduced in TnfΔARE/+ tpl2−/− splenocytes relative to TnfΔARE/+ controls (Fig. 5 B), suggesting that the absence of Tpl2 affects the pathogenic lymphocytic responses.

Bottom Line: Tissue-specific activation of the mutant TNF allele by Cre/loxP-mediated recombination indicated that either myeloid- or T cell-derived TNF can exhibit full pathogenic capacity.Interestingly, TNF-mediated intestinal pathology was exacerbated in the absence of MAPKAP kinase 2, yet strongly attenuated in a Cot/Tpl2 or JNK2 kinase-deficient genetic background.Our data establish the existence of redundant cellular pathways operating downstream of TNF in inflammatory bowel disease, and demonstrate the therapeutic potential of selective kinase blockade in TNF-mediated intestinal pathology.

View Article: PubMed Central - PubMed

Affiliation: Institute for Immunology, Biomedical Sciences Research Center "Al. Fleming," Vari 166-72, Greece. Division of Gastroenterology and Hepatology, University of Virginia Health Sciences Center, Charlottesville, VA 22906, USA.

ABSTRACT
Recent clinical evidence demonstrated the importance of tumor necrosis factor (TNF) in the development of Crohn's disease. A mouse model for this pathology has previously been established by engineering defects in the translational control of TNF mRNA (Tnf(Delta)(ARE) mouse). Here, we show that development of intestinal pathology in this model depends on Th1-like cytokines such as interleukin 12 and interferon gamma and requires the function of CD8(+) T lymphocytes. Tissue-specific activation of the mutant TNF allele by Cre/loxP-mediated recombination indicated that either myeloid- or T cell-derived TNF can exhibit full pathogenic capacity. Moreover, reciprocal bone marrow transplantation experiments using TNF receptor-deficient mice revealed that TNF signals are equally pathogenic when directed independently to either bone marrow-derived or tissue stroma cell targets. Interestingly, TNF-mediated intestinal pathology was exacerbated in the absence of MAPKAP kinase 2, yet strongly attenuated in a Cot/Tpl2 or JNK2 kinase-deficient genetic background. Our data establish the existence of redundant cellular pathways operating downstream of TNF in inflammatory bowel disease, and demonstrate the therapeutic potential of selective kinase blockade in TNF-mediated intestinal pathology.

Show MeSH
Related in: MedlinePlus