RESUMO
Fibroblasts are major contributors to and regulators of inflammation and dominant producers of interleukin-6 (IL-6) in inflammatory diseases like rheumatoid arthritis. Yet, compared to leukocytes, the regulation of inflammatory pathways in fibroblasts is largely unknown. Here, we report that analyses of genes coordinately upregulated with IL-6 pointed to STAT4 and leukemia inhibitory factor (LIF) as potentially linked. Gene silencing revealed that STAT4 was required for IL-6 transcription. STAT4 was recruited to the IL-6 promoter after fibroblast activation, and LIF receptor (LIFR) and STAT4 formed a molecular complex that, together with JAK1 and TYK2 kinases, controlled STAT4 activation. Importantly, a positive feedback loop involving autocrine LIF, LIFR, and STAT4 drove sustained IL-6 transcription. Besides IL-6, this autorine loop also drove the production of other key inflammatory factors including IL-8, granulocyte-colony stimulating factor (G-CSF), IL-33, IL-11, IL-1α, and IL-1ß. These findings define the transcriptional regulation of fibroblast-mediated inflammation as distinct from leukocytes.
Assuntos
Comunicação Autócrina/imunologia , Fibroblastos/imunologia , Regulação da Expressão Gênica/imunologia , Fator Inibidor de Leucemia/imunologia , Receptores de OSM-LIF/imunologia , Artrite Reumatoide/imunologia , Células Cultivadas , Citocinas/biossíntese , Perfilação da Expressão Gênica , Humanos , Inflamação/imunologia , Interleucina-6/imunologia , Fator de Transcrição STAT4/imunologia , Membrana Sinovial/imunologia , TranscriptomaRESUMO
Immunotherapy is a promising approach for specific targeting of cancer cells. Leukemia inhibitory factor (LIF) regulates several features of cancers and cancer stem cells (CSCs) through binding to LIF receptor (LIFR). In this study, we investigated the consensus of LIF and LIFR immunization on the growth of mouse mammary tumors. For this purpose, mouse LIF and LIFR were designed as truncated proteins, expressed in E. coli and then injected to mice as individual and mixed antigens. The results showed the production of neutralizing antibodies and secretion of interferon-γ and interleukin-2 in response to immunization. In continue, the immunized mice were subjected for tumor formation challenge by inoculation of the breast CSCs derived from MC4-L2 cells. Development of the breast tumors was observed in all the control mice, while the tumors appeared in 75% of animals in the LIF group. LIFR injection, individually or in combination with LIF, strongly inhibited the tumor growth to only 25% of the mice. Moreover, a delay in tumor appearance was observed in the immunized mice compared to the controls. Immunostaining of the tumor sections confirmed the expression of LIF and LIFR. In conclusion, LIF and LIFR might be effective targets for immunotherapy of the tumors that express these proteins.
Assuntos
Neoplasias da Mama/genética , Fator Inibidor de Leucemia/genética , Células-Tronco Neoplásicas/imunologia , Receptores de OSM-LIF/genética , Animais , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Modelos Animais de Doenças , Feminino , Inibidores do Crescimento/imunologia , Humanos , Imunização , Interleucina-6/genética , Fator Inibidor de Leucemia/imunologia , Camundongos , Ligação Proteica/genética , Receptores de OSM-LIF/imunologiaRESUMO
Leukemia inhibitory factor (LIF) is the most pleiotropic member of the interleukin-6 family of cytokines. It utilises a receptor that consists of the LIF receptor ß and gp130 and this receptor complex is also used by ciliary neurotrophic growth factor (CNTF), oncostatin M, cardiotrophin1 (CT1) and cardiotrophin-like cytokine (CLC). Despite common signal transduction mechanisms (JAK/STAT, MAPK and PI3K) LIF can have paradoxically opposite effects in different cell types including stimulating or inhibiting each of cell proliferation, differentiation and survival. While LIF can act on a wide range of cell types, LIF knockout mice have revealed that many of these actions are not apparent during ordinary development and that they may be the result of induced LIF expression during tissue damage or injury. Nevertheless LIF does appear to have non-redundant actions in maternal receptivity to blastocyst implantation, placental formation and in the development of the nervous system. LIF has also found practical use in the maintenance of self-renewal and totipotency of embryonic stem cells and induced pluripotent stem cells.
Assuntos
Fator Inibidor de Leucemia/imunologia , Sistema de Sinalização das MAP Quinases/imunologia , Animais , Blastocisto/imunologia , Receptor gp130 de Citocina/genética , Receptor gp130 de Citocina/imunologia , Implantação do Embrião/genética , Implantação do Embrião/imunologia , Regulação da Expressão Gênica/genética , Regulação da Expressão Gênica/imunologia , Células-Tronco Embrionárias Humanas/imunologia , Humanos , Janus Quinases/genética , Janus Quinases/imunologia , Fator Inibidor de Leucemia/genética , Sistema de Sinalização das MAP Quinases/genética , Camundongos , Camundongos Knockout , Células-Tronco Embrionárias Murinas/imunologia , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/imunologia , Receptores de OSM-LIF/genética , Receptores de OSM-LIF/imunologia , Fatores de Transcrição STAT/genética , Fatores de Transcrição STAT/imunologiaRESUMO
Leukemia inhibitory factor (LIF) receptor is a cell surface receptor that mediates the actions of LIF and other IL-6 type cytokines through the formation of high-affinity signaling complexes with gp130. Here we present the crystal structure of a complex of mouse LIF receptor with human LIF at 4.0 A resolution. The structure is, to date, the largest cytokine receptor fragment determined by x-ray crystallography. The binding of LIF to its receptor via the central Ig-like domain is unlike other cytokine receptor complexes that bind ligand predominantly through their cytokine-binding modules. This structure, in combination with previous crystallographic studies, also provides a structural template to understand the formation and orientation of the high-affinity signaling complex between LIF, LIF receptor, and gp130.