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Kobayashi K.,Kyoto University | Toguchida J.,Kyoto University | Karin M.,Laboratory of Gene Regulation and Signal Transduction | Kato T.,Kyoto University
Cell Death and Differentiation | Year: 2015

IκB kinase β (IKKβ) is a catalytic subunit of the IKK complex, which activates nuclear factor-κB (NF-κB). Although its role in osteoclastogenesis is well established, the role of IKKβ in bone formation is poorly understood. Here, we report that conditional knockout of Ikkβ in limb bud mesenchymal cells results in the upregulation of monocyte chemoattractant protein-5 (MCP-5) in the perichondrium, which in turn inhibits the growth of longitudinal bone by compromising chondrocyte hypertrophy and increasing the apoptosis of chondrocytes within the growth plate. Contrary to expectations, IKKβ in cells of chondrocyte or osteoblast lineage was dispensable for bone growth. On the other hand, ex vivo experiments confirmed the role of MCP-5 in the growth of longitudinal bone. Furthermore, an in vitro study demonstrated that the action of IKKβ on MCP-5 is cell autonomous. Collectively, our results provide evidence for a previously unrecognized role of IKKβ in the regulation of the growth plate that is mediated through stimulation-independent downregulation of MCP-5 in the perichondrium. © 2015 Macmillan Publishers Limited All rights reserved. Source

Kessler R.,Institute of Molecular Biology of Barcelona | Kessler R.,Barcelona Institute for Research in Biomedicine | Tisserand J.,Institute of Molecular Biology of Barcelona | Tisserand J.,Barcelona Institute for Research in Biomedicine | And 10 more authors.
Nature Communications | Year: 2015

dDsk2 is a conserved extraproteasomal ubiquitin receptor that targets ubiquitylated proteins for degradation. Here we report that dDsk2 plays a nonproteolytic function in transcription regulation. dDsk2 interacts with the dHP1c complex, localizes at promoters of developmental genes and is required for transcription. Through the ubiquitin-binding domain, dDsk2 interacts with H2Bub1, a modification that occurs at dHP1c complex-binding sites. H2Bub1 is not required for binding of the complex; however, dDsk2 depletion strongly reduces H2Bub1. Co-depletion of the H2Bub1 deubiquitylase dUbp8/Nonstop suppresses this reduction and rescues expression of target genes. RNA polymerase II is strongly paused at promoters of dHP1c complex target genes and dDsk2 depletion disrupts pausing. Altogether, these results suggest that dDsk2 prevents dUbp8/Nonstop-dependent H2Bub1 deubiquitylation at promoters of dHP1c complex target genes and regulates RNA polymerase II pausing. These results expand the catalogue of nonproteolytic functions of ubiquitin receptors to the epigenetic regulation of chromatin modifications. © 2015 Macmillan Publishers Limited. All rights reserved. Source

Grivennikov S.I.,Laboratory of Gene Regulation and Signal Transduction | Karin M.,Laboratory of Gene Regulation and Signal Transduction
Cytokine and Growth Factor Reviews | Year: 2010

Transcriptional factors of the NF-κB family and STAT3 are ubiquitously expressed and control numerous physiological processes including development, differentiation, immunity, metabolism and cancer. Both NF-κB and STAT3 are rapidly activated in response to various stimuli including stresses and cytokines, although they are regulated by entirely different signaling mechanisms. Once activated, NF-κB and STAT3 control the expression of anti-apoptotic, pro-proliferative and immune response genes. Some of these genes overlap and require transcriptional cooperation between the two factors. The activation of and interaction between STAT3 and NF-κB plays a key role in controlling the dialog between the malignant cell and its microenvironment, especially with inflammatory/immune cells that infiltrate tumors. Quite often, cytokines whose expression is induced in response to NF-κB in immune cells of the tumor microenvironment lead to STAT3 activation in both malignant and immune cells. While within malignant and pre-malignant cells STAT3 exerts important oncogenic functions, within inflammatory cells it may also suppress tumor promotion through its anti-inflammatory effects. Other interactions and forms of crosstalk between NF-κB and STAT3 include physical interaction between the two, cooperation of these factors at gene promoters/enhancers, the NF-κB dependent expression of inhibitors of STAT3 activation and the participation of STAT3 in inflammatory cells in the negative regulation NF-κB. Despite these versatile and occasionally antagonistic interactions, NF-κB and STAT3 cooperate to promote the development and progression of colon, gastric and liver cancers. In addition to explaining the molecular pathogenesis of cancer, these interactions also offer opportunities for the design of new therapeutic interventions. © 2009 Elsevier Ltd. All rights reserved. Source

Shalapour S.,Laboratory of Gene Regulation and Signal Transduction | Karin M.,Laboratory of Gene Regulation and Signal Transduction
Journal of Clinical Investigation | Year: 2015

Cancer development and its response to therapy are strongly influenced by innate and adaptive immunity, which either promote or attenuate tumorigenesis and can have opposing effects on therapeutic outcome. Chronic inflammation promotes tumor development, progression, and metastatic dissemination, as well as treatment resistance. However, cancer development and malignant progression are also associated with accumulation of genetic alterations and loss of normal regulatory processes, which cause expression of tumor-specific antigens and tumor-Associated antigens (TAAs) that can activate antitumor immune responses. Although signals that trigger acute inflammatory reactions often stimulate dendritic cell maturation and antigen presentation, chronic inflammation can be immunosuppressive. This antagonism between inflammation and immunity also affects the outcome of cancer treatment and needs to be considered when designing new therapeutic approaches. Source

Grivennikov S.I.,Laboratory of Gene Regulation and Signal Transduction | Karin M.,Laboratory of Gene Regulation and Signal Transduction
Current Opinion in Genetics and Development | Year: 2010

Epidemiological and experimental data suggest a close connection between inflammation and tumorigenesis. Solid tumors are typically infiltrated with immune cells and inflammation impacts most, if not all, stages of tumorigenesis. Molecular and cellular pathways, which connect inflammation and cancer, have emerged as attractive targets for prevention and therapy. In this review we discuss general mechanisms and concepts of cancer promoting inflammation. © 2009 Elsevier Ltd. All rights reserved. Source

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