RESUMO
LIM homeobox 4 (LHX4) is a transcription factor crucial for anterior pituitary (AP) development. Patients with LHX4 mutation suffer from combined pituitary hormone deficiency (CPHD), short statures, reproductive and metabolic disorders and lethality in some cases. Lhx4-knockout (KO) mice fail to develop a normal AP and die shortly after birth. Here, we characterize a zebrafish lhx4-KO model to further investigate the importance of LHX4 in pituitary gland development and regulation. At the embryonic and larval stages, these fish express lower levels of tshb mRNA compared with their wildtype siblings. In adult lhx4-KO fish, the expressions of pituitary hormone-encoding transcripts, including growth hormone (gh), thyroid stimulating hormone (tshb), proopiomelanocortin (pomca) and follicle stimulating hormone (fshb), are reduced, the pomca promoter-driven expression in corticotrophs is dampened and luteinizing hormone (lhb)-producing gonadotrophs are severely depleted. In contrast to Lhx4-KO mice, Lhx4-deficient fish survive to adulthood, but with a reduced body size. Importantly, lhx4-KO males reach sexual maturity and are reproductively competent, whereas the females remain infertile with undeveloped ovaries. These phenotypes, which are reminiscent of those observed in CPHD patients, along with the advantages of the zebrafish for developmental genetics research, make this lhx4-KO fish an ideal vertebrate model to study the outcomes of LHX4 mutation.
Assuntos
Hipopituitarismo , Proteínas com Homeodomínio LIM , Proteínas de Peixe-Zebra , Peixe-Zebra , Animais , Peixe-Zebra/genética , Proteínas com Homeodomínio LIM/genética , Proteínas com Homeodomínio LIM/metabolismo , Proteínas com Homeodomínio LIM/deficiência , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/deficiência , Hipopituitarismo/genética , Hipopituitarismo/metabolismo , Masculino , Feminino , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/deficiência , Técnicas de Inativação de Genes , Hipófise/metabolismo , Modelos Animais de Doenças , Animais Geneticamente ModificadosRESUMO
Nonreceptor tyrosine kinase c-Abl participates in several cellular processes by phosphorylating transcription factors or cofactors. c-Abl binds and phosphorylates four-and-a-half-LIM-only protein 2 (FHL2), but the identity of the phosphorylation sites and their contribution to cell cycle regulation is unclear. In this study, we demonstrate that c-Abl highly phosphorylates FHL2 at Y97, Y176, Y217, and Y236 through mass spectrometry and tyrosine-to-phenylalanine (Y â F) mutant analysis. Proliferation was inhibited in cells expressing wild-type (WT) FHL2 but not cells expressing the phosphorylation-defective mutant FHL2(4YF). Moreover, FHL2 contributed to cell cycle arrest at G2/M induced by ionizing radiation (IR). FHL2 WT but not FHL2(4YF) rescued FHL2 function in FHL2-depleted cells by causing IR-induced G2/M arrest. These results demonstrate that c-Abl regulates cell cycle progression by phosphorylating FHL2.
Assuntos
Proteínas com Homeodomínio LIM/metabolismo , Proteínas Musculares/metabolismo , Proteínas Proto-Oncogênicas c-abl/metabolismo , Fatores de Transcrição/metabolismo , Proliferação de Células , Células Cultivadas , Pontos de Checagem da Fase G2 do Ciclo Celular , Humanos , Proteínas com Homeodomínio LIM/deficiência , Proteínas Musculares/deficiência , Fosforilação , Radiação Ionizante , Fatores de Transcrição/deficiênciaRESUMO
The transcription factor ISL1 is expressed in pituitary gland stem cells and the thyrotrope and gonadotrope lineages. Pituitary-specific Isl1 deletion causes hypopituitarism with increased stem cell apoptosis, reduced differentiation of thyrotropes and gonadotropes, and reduced body size. Conditional Isl1 deletion causes development of multiple Rathke's cleft-like cysts, with 100% penetrance. Foxa1 and Foxj1 are abnormally expressed in the pituitary gland and associated with a ciliogenic gene-expression program in the cysts. We confirmed expression of FOXA1, FOXJ1, and stem cell markers in human Rathke's cleft cyst tissue, but not craniopharyngiomas, which suggests these transcription factors are useful, pathological markers for diagnosis of Rathke's cleft cysts. These studies support a model whereby expression of ISL1 in pituitary progenitors drives differentiation into thyrotropes and gonadotropes and without it, activation of FOXA1 and FOXJ1 permits development of an oral epithelial cell fate with mucinous cysts. This pituitary-specific Isl1 mouse knockout sheds light on the etiology of Rathke's cleft cysts and the role of ISL1 in normal pituitary development.
Assuntos
Cistos do Sistema Nervoso Central/metabolismo , Deleção de Genes , Proteínas com Homeodomínio LIM/deficiência , Proteínas de Neoplasias/deficiência , Hipófise/metabolismo , Células-Tronco/metabolismo , Fatores de Transcrição/deficiência , Animais , Cistos do Sistema Nervoso Central/genética , Cistos do Sistema Nervoso Central/patologia , Proteínas com Homeodomínio LIM/metabolismo , Camundongos , Camundongos Knockout , Proteínas de Neoplasias/metabolismo , Hipófise/patologia , Células-Tronco/patologia , Fatores de Transcrição/metabolismoRESUMO
Cholestasis occurs in different clinical circumstances and leads to severe hepatic disorders. The four-and-a-half LIM-domain protein 2 (FHL2) is a scaffolding protein that modulates multiple signal transduction pathways in a tissue- and cell context-specific manner. In this study, we aimed to gain insight into the function of FHL2 in cholestatic liver injury. FHL2 expression was significantly increased in the bile duct ligation (BDL) model in mice. In Fhl2-deficient (Fhl2-ko) mice, BDL caused a more severe portal and parenchymal inflammation, extended portal fibrosis, higher serum transaminase levels, and higher pro-inflammatory and pro-fibrogenic gene expression compared to wild type (wt) mice. FHL2 depletion in HepG2 cells with siRNA resulted in a higher expression of the bile acid transporter Na+-taurocholate cotransporting polypeptide (NTCP) gene. Furthermore, FHL2-depleted HepG2 cells showed higher expression of markers for oxidative stress, lower B-cell lymphoma 2 (Bcl2) expression, and higher Bcl2-associated X protein (BAX) expression after stimulation with deoxycholic acid (DCA). In hepatic stellate cells (HSCs), FHL2 depletion caused an increased expression of TGF-ß and several pro-fibrogenic matrix metalloproteinases. In summary, our study shows that deficiency in FHL2 aggravates cholestatic liver injury and suggests FHL2-mediated effects on bile acid metabolisms and HSCs as potential mechanisms for pronounced hepatocellular injury and fibrosis.
Assuntos
Colestase/metabolismo , Colestase/patologia , Proteínas com Homeodomínio LIM/deficiência , Fígado/lesões , Proteínas Musculares/deficiência , Fatores de Transcrição/deficiência , Animais , Ácidos e Sais Biliares/metabolismo , Ductos Biliares/patologia , Modelos Animais de Doenças , Regulação da Expressão Gênica , Células Hep G2 , Células Estreladas do Fígado/metabolismo , Células Estreladas do Fígado/patologia , Humanos , Inflamação/patologia , Proteínas com Homeodomínio LIM/metabolismo , Ligadura , Fígado/patologia , Cirrose Hepática/patologia , Masculino , Camundongos Knockout , Proteínas Musculares/metabolismo , Fatores de Transcrição/metabolismoRESUMO
Despite the advent of new-generation drug-eluting stents, in-stent restenosis remains a significant problem in patients with coronary artery disease. In- stent restenosis is defined as the gradual re-narrowing of a stented coronary artery lesion due to arterial damage with subsequent local inflammation of the vessel wall and excessive growth of the vascular smooth muscle cells (vSMCs). Four-and-a-half LIM-domain protein 2 (FHL2) is a scaffold protein involved in regulating vSMC function and inflammation. Previously we have demonstrated that FHL2 prevents vSMC proliferation in a murine carotid artery ligation model. However, the effect of FHL2 on the inflammatory response of the vSMCs is not investigated. Therefore, we studied the inflammatory response in the vessel wall of FHL2-deficient (-KO) mice after carotid artery ligation. We found that circulating cytokines and local macrophage infiltration in the ligated carotid vessels were increased in FHL2-KO mice after carotid artery ligation. Moreover, FHL2-KO vSMCs showed increased secretion of cytokines such as SDF-1α and RANTES, and enhanced activation of the NFκB pathway. Finally, we found that blocking the NFκB signalling pathway abrogated this pro-inflammatory state in FHL2-KO vSMCs. Taken together, our results demonstrate that FHL2 decreases the inflammatory response of vSMCs through inhibition of the NFkB-signalling pathway.
Assuntos
Doenças das Artérias Carótidas/metabolismo , Inflamação/metabolismo , Proteínas com Homeodomínio LIM/metabolismo , Proteínas Musculares/metabolismo , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/metabolismo , NF-kappa B/metabolismo , Fatores de Transcrição/metabolismo , Animais , Anti-Inflamatórios/farmacologia , Artérias Carótidas/metabolismo , Artérias Carótidas/patologia , Doenças das Artérias Carótidas/genética , Doenças das Artérias Carótidas/patologia , Doenças das Artérias Carótidas/prevenção & controle , Células Cultivadas , Citocinas/sangue , Modelos Animais de Doenças , Inflamação/genética , Inflamação/patologia , Inflamação/prevenção & controle , Proteínas com Homeodomínio LIM/deficiência , Proteínas com Homeodomínio LIM/genética , Macrófagos/metabolismo , Macrófagos/patologia , Camundongos Knockout , Proteínas Musculares/deficiência , Proteínas Musculares/genética , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/patologia , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/patologia , NF-kappa B/antagonistas & inibidores , NF-kappa B/genética , Transdução de Sinais , Fatores de Transcrição/deficiência , Fatores de Transcrição/genéticaRESUMO
The 4-and-a-half LIM domain protein 2 (FHL2) is a multifunctional adaptor protein that can interact with cell surface receptors, cytosolic adaptor and structural proteins, kinases, and nuclear transcription factors. It is involved in numerous functional activities, including the epithelial-mesenchymal transition, cell proliferation, apoptosis, adhesion, migration, structural stability, and gene expression. Despite this, FHL2-knockout (KO) mice are viable and fertile with no obvious abnormalities, rather suggesting a high capacity for fine-tuning adjustment and functional redundancy of FHL2. Indeed, challenging FHL2-KO cells or mice provided numerous evidences for the great functional significance of FHL2. In recent years, several reviews have been published describing the high capacity of FHL2 to bind diverse proteins as well as the versatile functions of FHL2, emphasizing in particular its role in cardiovascular diseases and carcinogenesis. Here, we view the function of FHL2 from a different perspective. We summarize the published data demonstrating the impact of FHL2 on wound healing and inflammation. FHL2 seems to be involved in numerous steps of these extremely complex and multidirectional but tightly regulated tissue remodeling processes, supporting tissue repair and coordinating inflammation. Deficiency of FHL2 not only slows down ongoing wound healing but also often turns it into a chronic condition.-Wixler, V. The role of FHL2 in wound healing and inflammation.
Assuntos
Inflamação/fisiopatologia , Proteínas com Homeodomínio LIM/fisiologia , Proteínas Musculares/fisiologia , Fatores de Transcrição/fisiologia , Cicatrização/fisiologia , Animais , Quimiotaxia de Leucócito/fisiologia , Citocinas/fisiologia , Transição Epitelial-Mesenquimal/fisiologia , Inflamação/imunologia , Proteínas com Homeodomínio LIM/biossíntese , Proteínas com Homeodomínio LIM/deficiência , Proteínas com Homeodomínio LIM/genética , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Proteínas Musculares/biossíntese , Proteínas Musculares/deficiência , Proteínas Musculares/genética , Miofibroblastos/fisiologia , Regeneração/fisiologia , Transdução de Sinais/fisiologia , Fatores de Transcrição/biossíntese , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Transcrição Gênica/fisiologia , Regulação para CimaRESUMO
FHL2, a member of the four and one half LIM domain protein family, is a critical transcriptional modulator. Here, we identify FHL2 as a critical regulator of hematopoietic stem cells (HSCs) that is essential for maintaining HSC self-renewal under regenerative stress. We find that Fhl2 loss has limited effects on hematopoiesis under homeostatic conditions. In contrast, Fhl2-null chimeric mice reconstituted with Fhl2-null bone marrow cells developed abnormal hematopoiesis with significantly reduced numbers of HSCs, hematopoietic progenitor cells (HPCs), red blood cells and platelets as well as hemoglobin levels. In addition, HSCs displayed a significantly reduced self-renewal capacity and were skewed toward myeloid lineage differentiation. We find that Fhl2 loss reduces both HSC quiescence and survival in response to regenerative stress, probably as a consequence of Fhl2-loss-mediated downregulation of cyclin-dependent kinase-inhibitors, including p21(Cip) and p27(Kip1). Interestingly, FHL2 is regulated under the control of a tissue-specific promoter in hematopoietic cells and it is downregulated by DNA hypermethylation in the leukemia cell line and primary leukemia cells. Furthermore, we find that downregulation of FHL2 frequently occurs in myelodysplastic syndrome and acute myeloid leukemia patients, raising a possibility that FHL2 downregulation has a role in the pathogenesis of myeloid malignancies.
Assuntos
Transplante de Medula Óssea , Regulação da Expressão Gênica , Proteínas com Homeodomínio LIM/genética , Leucemia Mieloide Aguda/genética , Proteínas Musculares/genética , Síndromes Mielodisplásicas/genética , Fatores de Transcrição/genética , Animais , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Proliferação de Células , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Metilação de DNA , Hematopoese , Células-Tronco Hematopoéticas/metabolismo , Células-Tronco Hematopoéticas/patologia , Humanos , Proteínas com Homeodomínio LIM/deficiência , Proteínas com Homeodomínio LIM/metabolismo , Leucemia Mieloide Aguda/metabolismo , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Knockout , Proteínas Musculares/deficiência , Proteínas Musculares/metabolismo , Síndromes Mielodisplásicas/metabolismo , Síndromes Mielodisplásicas/patologia , Regiões Promotoras Genéticas , Transdução de Sinais , Estresse Fisiológico , Fatores de Transcrição/deficiência , Fatores de Transcrição/metabolismo , Transplante Isogênico , Irradiação Corporal TotalRESUMO
Enteroendocrine cells secrete over a dozen different hormones responsible for coordinating digestion, absorption, metabolism, and gut motility. Loss of enteroendocrine cells is a known cause of severe congenital diarrhea. Furthermore, enteroendocrine cells regulate glucose metabolism, with the incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) playing critical roles in stimulating insulin release by pancreatic ß-cells. Islet1 (Isl1) is a LIM-homeodomain transcription factor expressed specifically in an array of intestinal endocrine cells, including incretin-expressing cells. To examine the impact of intestinal Isl1 on glycemic control, we set out to explore the role of intestinal Isl1 in hormone cell specification and organismal physiology. Mice with intestinal epithelial-specific ablation of Isl1 were obtained by crossing Villin-Cre transgenic animals with mice harboring a Isl1(loxP) allele (Isl1(int) model). Gene ablation of Isl1 in the intestine results in loss of GLP-1, GIP, cholecystokinin (CCK), and somatostatin-expressing cells and an increase in 5-HT (serotonin)-producing cells, while the chromogranin A population was unchanged. This dramatic change in hormonal milieu results in animals with lipid malabsorption and females smaller than their littermate controls. Interestingly, when challenged with oral, not intraperitoneal glucose, the Isl-1 intestinal-deficient animals (Isl1(int)) display impaired glucose tolerance, indicating loss of the incretin effect. Thus the Isl1(int) model confirms that intestinal biology is essential for organism physiology in glycemic control and susceptibility to diabetes.
Assuntos
Glicemia/metabolismo , Células Enteroendócrinas/metabolismo , Transtornos do Metabolismo de Glucose/metabolismo , Mucosa Intestinal/metabolismo , Intestino Delgado/metabolismo , Proteínas com Homeodomínio LIM/deficiência , Fatores de Transcrição/deficiência , Fatores Etários , Animais , Animais Recém-Nascidos , Biomarcadores/sangue , Colecistocinina/metabolismo , Cromogranina A/metabolismo , Diarreia/genética , Diarreia/metabolismo , Gorduras na Dieta/metabolismo , Células Enteroendócrinas/patologia , Feminino , Polipeptídeo Inibidor Gástrico/metabolismo , Gastrinas/metabolismo , Genótipo , Grelina/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Transtornos do Metabolismo de Glucose/sangue , Transtornos do Metabolismo de Glucose/genética , Teste de Tolerância a Glucose , Integrases/genética , Absorção Intestinal , Mucosa Intestinal/patologia , Intestino Delgado/patologia , Proteínas com Homeodomínio LIM/genética , Síndromes de Malabsorção/genética , Síndromes de Malabsorção/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas dos Microfilamentos/genética , Fenótipo , Serotonina/metabolismo , Somatostatina/metabolismo , Fatores de Transcrição/genética , Aumento de PesoRESUMO
A role for serotonin in male sexual preference was recently uncovered by our finding that male mutant mice lacking serotonin have lost sexual preference. Here we show that female mouse mutants lacking either central serotonergic neurons or serotonin prefer female over male genital odors when given a choice, and displayed increased female-female mounting when presented either with a choice of a male and a female target or only with a female target. Pharmacological manipulations and genetic rescue experiments showed that serotonin is required in adults. Behavioral changes caused by deficient serotonergic signaling were not due to changes in plasma concentrations of sex hormones. We demonstrate that a genetic manipulation reverses sexual preference without involving sex hormones. Our results indicate that serotonin controls sexual preference.
Assuntos
Preferência de Acasalamento Animal/fisiologia , Neurônios Serotoninérgicos/fisiologia , Serotonina/metabolismo , Transdução de Sinais/fisiologia , 5-Hidroxitriptofano/farmacologia , Animais , Antidepressivos de Segunda Geração/farmacologia , Estradiol/sangue , Estradiol/farmacologia , Estrogênios/farmacologia , Feminino , Genitália/química , Proteínas com Homeodomínio LIM/deficiência , Proteínas com Homeodomínio LIM/genética , Masculino , Preferência de Acasalamento Animal/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Odorantes , Orquiectomia , Ovariectomia , Neurônios Serotoninérgicos/metabolismo , Fatores Sexuais , Testosterona/sangue , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Triptofano Hidroxilase/deficiência , Triptofano Hidroxilase/genéticaRESUMO
OBJECTIVE: The four and a half Lin11, Isl-1 and Mec-3 (LIM) domain protein 2 (FHL2) is a member of the four and a half LIM domain-only (FHL) gene family, and has been shown to play an important role in inhibiting inflammatory angiogenesis. Here, we tested the hypothesis that impaired ischemia-induced neovascularization in mice lacking FHL2 is related to a defect in proangiogenic cell mobilization and functions in vasculogenesis. APPROACH AND RESULTS: Unilateral hindlimb ischemia surgery was conducted in FHL2(-/-) mice and wild-type (FHL2(+/+)) mice. After hindlimb ischemia surgery, expression of FHL2 protein was noted in ischemic tissues of wild-type mice. All FHL2-null mice (100%) suffered from spontaneous foot amputation, but only 20% of wild-type mice had ischemia-induced foot amputation after ischemic surgery. Blood flow recovery was significantly impaired in FHL2(-/-) mice when compared with that in wild-type mice as determined by laser Doppler imaging. Histological analysis revealed that the capillary density in the ischemic limb was increased in wild-type mice, whereas no such increase was noted in FHL2(-/-) mice. Flow cytometry demonstrated that the number of CD34(+) or CD34(+)/Sca-1(+)/Flk-1(+) in peripheral blood after ischemic surgery significantly decreased in FHL2-null mice than those in wild-type mice after hindlimb ischemia surgery. FHL2 deficiency impaired ex vivo angiogenesis in mouse aortic-ring culture assay, which revealed that the mean density of the microvessels was significantly higher in the wild-type aorta than in the FHL2(-/-) aorta. Western blot analysis showed that vascular endothelial growth factor (VEGF), interleukin-6, matrix metalloproteinase-2, matrix metalloproteinase-9, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 levels were significantly downregulated in ischemic muscles in FHL2-null mice compared with wild-type mice. Deletion of FHL2 protein by FHL2 small interfering RNA impaired VEGF production under hypoxia conditions, and also suppressed endothelial progenitor cell angiogenic functions, but these effects could be recovered by administration of VEGF. CONCLUSIONS: Deficiency of FHL2 impairs ischemia-induced neovascularization, and these suppressive effects may occur through a reduction in proangiogenic cell mobilization, migration, and vasculogenesis functions.
Assuntos
Capilares/metabolismo , Células Endoteliais/metabolismo , Isquemia/metabolismo , Proteínas com Homeodomínio LIM/deficiência , Proteínas Musculares/deficiência , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/metabolismo , Neovascularização Fisiológica , Células-Tronco/metabolismo , Fatores de Transcrição/deficiência , Animais , Antígenos CD34/sangue , Antígenos Ly/sangue , Biomarcadores/sangue , Western Blotting , Transplante de Medula Óssea , Capilares/patologia , Capilares/fisiopatologia , Células Cultivadas , Modelos Animais de Doenças , Células Endoteliais/patologia , Citometria de Fluxo , Membro Posterior , Humanos , Interleucina-6/metabolismo , Isquemia/genética , Isquemia/patologia , Isquemia/fisiopatologia , Proteínas com Homeodomínio LIM/genética , Proteínas com Homeodomínio LIM/metabolismo , Fluxometria por Laser-Doppler , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Proteínas de Membrana/sangue , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Músculo Esquelético/patologia , Interferência de RNA , Recuperação de Função Fisiológica , Fluxo Sanguíneo Regional , Células-Tronco/patologia , Fatores de Tempo , Técnicas de Cultura de Tecidos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transfecção , Molécula 1 de Adesão de Célula Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/sangueRESUMO
BACKGROUND: The molecular mechanisms that are involved in the growth and invasiveness of osteosarcoma, an aggressive and invasive primary bone tumor, are not fully understood. The transcriptional co-factor FHL2 (four and a half LIM domains protein 2) acts as an oncoprotein or as a tumor suppressor depending on the tissue context. In this study, we investigated the role of FHL2 in tumorigenesis in osteosarcoma model. METHODOLOGY/PRINCIPAL FINDINGS: Western blot analyses showed that FHL2 is expressed above normal in most human and murine osteosarcoma cells. Tissue microarray analysis revealed that FHL2 protein expression is high in human osteosarcoma and correlates with osteosarcoma aggressiveness. In murine osteosarcoma cells, FHL2 silencing using shRNA decreased canonical Wnt/ß-catenin signaling and reduced the expression of Wnt responsive genes as well as of the key Wnt molecules Wnt5a and Wnt10b. This effect resulted in inhibition of osteosarcoma cell proliferation, invasion and migration in vitro. Using xenograft experiments, we showed that FHL2 silencing markedly reduced tumor growth and lung metastasis occurence in mice. The anti-oncogenic effect of FHL2 silencing in vivo was associated with reduced cell proliferation and decreased Wnt signaling in the tumors. CONCLUSION/SIGNIFICANCE: Our findings demonstrate that FHL2 acts as an oncogene in osteosarcoma cells and contributes to tumorigenesis through Wnt signaling. More importantly, FHL2 depletion greatly reduces tumor cell growth and metastasis, which raises the potential therapeutic interest of targeting FHL2 to efficiently impact primary bone tumors.
Assuntos
Transformação Celular Neoplásica/genética , Inativação Gênica , Proteínas com Homeodomínio LIM/deficiência , Proteínas com Homeodomínio LIM/genética , Proteínas Musculares/deficiência , Proteínas Musculares/genética , Osteossarcoma/patologia , Transdução de Sinais/genética , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Proteínas Wnt/metabolismo , Animais , Apoptose/genética , Neoplasias Ósseas/tratamento farmacológico , Neoplasias Ósseas/genética , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Neoplasias Pulmonares/secundário , Camundongos , Terapia de Alvo Molecular , Invasividade Neoplásica , Osteossarcoma/tratamento farmacológico , Osteossarcoma/genética , RNA Interferente Pequeno/genética , beta Catenina/metabolismoRESUMO
OBJECTIVE: Lim1 (Lim homeobox 1) plays an important role during rodent renal development; however, its rolein human kidney development and disease is still unclear. METHODS: We investigated LIM1 expression during human renal development, in dysplastic kidneys and in renal neoplasms using immunohistochemistry. RNA levels in renal carcinomas were determined by quantitative RT-PCR, and the potential roles of LIM1 in mesenchymal-epithelial transition and cell cycle were investigated in a cell culture model. RESULTS: LIM1 was detected in pretubular aggregates, S-shaped and comma-shaped bodies as well as immature glomeruli between 10 and 30 weeks of gestation. Eleven dysplastic kidneys showed no expression of LIM1. In contrast, 12 of 32 nephroblastomas showed nuclear positivity. One regressive nephroblastoma had diffuse expression of LIM1 in tubular structures, all others showed focal positivity in mesenchymal, blastemal and epithelial structures. Renal cell carcinomas revealed no expression of LIM1. Overexpression of LIM1 in a cell culture model led to an increase in KERATIN7 expression but no change in the cell cycle. CONCLUSION: Our study supports the concept of a causative role of LIM1 deficiency in the development of multicystic kidney. In a small subset of nephroblastomas with a more diffuse expression pattern LIM1 might also contribute to the pathogenesis of these lesions.