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1.
Gastroenterology ; 152(1): 218-231.e14, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27670082

RESUMO

BACKGROUND & AIMS: Little is known about the mechanisms of gastric carcinogenesis, partly because it has been a challenge to identify characterize gastric stem cells. Runx genes regulate development and their products are transcription factors associated with cancer development. A Runx1 enhancer element, eR1, is a marker of hematopoietic stem cells. We studied expression from eR1 in the stomach and the roles of gastric stem cells in gastric carcinogenesis in transgenic mice. METHODS: We used in situ hybridization and immunofluorescence analyses to study expression of Runx1 in gastric tissues from C57BL/6 (control) mice. We then created mice that expressed enhanced green fluorescent protein (EGFP) or CreERT2 under the control of eR1 (eR1-CreERT2;Rosa-Lox-Stop-Lox [LSL]-tdTomato, eR1-CreERT2;Rosa-LSL-EYFP mice). Gastric tissues were collected and lineage-tracing experiments were performed. Gastric organoids were cultured from eR1-CreERT2(5-2);Rosa-LSL-tdTomato mice and immunofluorescence analyses were performed. We investigated the effects of expressing oncogenic mutations in stem cells under control of eR1 using eR1-CreERT2;LSL-KrasG12D/+ mice; gastric tissues were collected and analyzed by histology and immunofluorescence. RESULTS: Most proliferation occurred in the isthmus; 86% of proliferating cells were RUNX1-positive and 76% were MUC5AC-positive. In eR1-EGFP mice, EGFP signals were detected mainly in the upper part of the gastric unit, and 83% of EGFP-positive cells were located in the isthmus/pit region. We found that eR1 marked undifferentiated stem cells in the isthmus and a smaller number of terminally differentiated chief cells at the base. eR1 also marked cells in the pyloric gland in the antrum. Lineage-tracing experiments demonstrated that stem cells in the isthmus and antrum continuously gave rise to mature cells to maintain the gastric unit. eR1-positive cells in the isthmus and pyloric gland generated organoid cultures in vitro. In eR1-CreERT2;LSL-Kras G12D/+ mice, MUC5AC-positive cells rapidly differentiated from stem cells in the isthmus, resulting in distinct metaplastic lesions similar to that observed in human gastric atrophy. CONCLUSIONS: Using lineage-tracing experiments in mice, we found that a Runx1 enhancer element, eR1, promotes its expression in the isthmus stem cells of stomach corpus as well as pyloric gland in the antrum. We were able to use eR1 to express oncogenic mutations in gastric stem cells, proving a new model for studies of gastric carcinogenesis.


Assuntos
Subunidade alfa 2 de Fator de Ligação ao Core/genética , Elementos Facilitadores Genéticos/genética , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patologia , Antro Pilórico/patologia , RNA Mensageiro/metabolismo , Células-Tronco/metabolismo , Células-Tronco/patologia , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Animais , Carcinogênese , Diferenciação Celular , Linhagem da Célula , Proliferação de Células , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Expressão Gênica , Proteínas de Fluorescência Verde/genética , Humanos , Antígeno Ki-67/metabolismo , Metaplasia/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mucina-5AC/metabolismo , Antro Pilórico/metabolismo , Técnicas de Cultura de Tecidos
2.
Int Immunol ; 26(7): 397-406, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24569264

RESUMO

Activation-induced cytidine deaminase (AID) not only promotes immune diversity by initiating somatic hypermutation and class switch recombination in immunoglobulin genes but also provokes genomic instability by introducing translocations and mutations into non-immunoglobulin genes. To test whether AID is essential for virus-induced tumor development, we used two transgenic tumor models: mice expressing hepatitis C virus (HCV) core proteins (HCV-Tg), driven by the hepatitis B virus promoter, and mice expressing human papillomavirus type 8 proteins (HPV8-Tg), driven by the Keratin 14 promoter. Both strains were analyzed in the absence and presence of AID by crossing each with AID (-/-) mice. There was no difference in the liver tumor frequency between the HCV-Tg/AID (+/+) and HCV-Tg/AID (-/-) mice at 20 months of age although the AID (+/+) mice showed more severe histological findings and increased cytokine expression. Furthermore, a low level of AID transcript was detected in the HCV-Tg/AID (+/+) liver tissue that was not derived from hepatocytes themselves but from intra-hepatic immune cells. Although AID may not be the direct cause of HCV-induced oncogenesis, AID expressed in B cells, not in hepatocytes, may prolong steatosis and cause increased lymphocyte infiltration into HCV core protein-induced liver lesions. Similarly, there was no difference in the time course of skin tumor development between the HPV8-Tg/AID (-/-) and HPV8-Tg/AID (+/+) groups. In conclusion, AID does not appear to be required for tumor development in the two virus-induced tumor mouse models tested although AID expressed in infiltrating B cells may promote inflammatory reactions in HCV core protein-induced liver pathogenesis.


Assuntos
Carcinoma Hepatocelular/genética , Citidina Desaminase/genética , Hepatite C/genética , Neoplasias Hepáticas/genética , Papiloma/genética , Infecções por Papillomavirus/genética , Neoplasias Cutâneas/genética , Animais , Linfócitos B/metabolismo , Linfócitos B/patologia , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patologia , Citidina Desaminase/deficiência , Modelos Animais de Doenças , Feminino , Regulação Neoplásica da Expressão Gênica , Hepatite C/metabolismo , Hepatite C/patologia , Hepatócitos/metabolismo , Hepatócitos/patologia , Humanos , Fígado/metabolismo , Fígado/patologia , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patologia , Masculino , Camundongos , Camundongos Transgênicos , Papiloma/metabolismo , Papiloma/patologia , Papillomaviridae/patogenicidade , Infecções por Papillomavirus/metabolismo , Infecções por Papillomavirus/patologia , Regiões Promotoras Genéticas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Pele/metabolismo , Pele/patologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Proteínas do Core Viral/genética , Proteínas do Core Viral/metabolismo
3.
Cell Struct Funct ; 39(2): 113-24, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25311449

RESUMO

The dedicator of cytokinesis (DOCK) family proteins that are conserved in a wide variety of species are known as DOCK1-DOCK11 in mammals. The Sponge (Spg) is a Drosophila counterpart to the mammalian DOCK3. Specific knockdown of spg by pannir-GAL4 or apterous-GAL4 driver in wing discs induced split thorax phenotype in adults. Reduction of the Drosophila c-Jun N-terminal kinase (JNK), basket (bsk) gene dose enhanced the spg knockdown-induced phenotype. Conversely, overexpression of bsk suppressed the split thorax phenotype. Monitoring JNK activity in the wing imaginal discs by immunostaining with anti-phosphorylated JNK (anti-pJNK) antibody together with examination of lacZ expression in a puckered-lacZ enhancer trap line revealed the strong reduction of the JNK activity in the spg knockdown clones. This was further confirmed by Western immunoblot analysis of extracts from wing discs of spg knockdown fly with anti-pJNK antibody. Furthermore, the Duolink in situ Proximity Ligation Assay method detected interaction signals between Spg and Rac1 in the wing discs. Taken together, these results indicate Spg positively regulates JNK pathway that is required for thorax development and the regulation is mediated by interaction with Rac1.


Assuntos
Proteínas de Transporte/fisiologia , Proteínas de Drosophila/fisiologia , Drosophila melanogaster/crescimento & desenvolvimento , Sistema de Sinalização das MAP Quinases , Animais , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Feminino , Técnicas de Silenciamento de Genes , Discos Imaginais/metabolismo , Larva/crescimento & desenvolvimento , Larva/metabolismo , Masculino , Especificidade de Órgãos , Fenótipo , Proteínas rac de Ligação ao GTP/metabolismo
4.
Exp Cell Res ; 319(14): 2179-95, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23747680

RESUMO

The Drosophila sponge (spg)/CG31048 gene belongs to the dedicator of cytokinesis (DOCK) family genes that are conserved in a wide variety of species. DOCK family members are known as DOCK1-DOCK11 in mammals. Although DOCK1 and DOCK2 involve neurite elongation and immunocyte differentiation, respectively, the functions of other DOCK family members are not fully understood. Spg is a Drosophila homolog of mammalian DOCK3 and DOCK4. Specific knockdown of spg by the GMR-GAL4 driver in eye imaginal discs induced abnormal eye morphology in adults. To mark the photoreceptor cells in eye imaginal discs, we used a set of enhancer trap strains that express lacZ in various sets of photoreceptor cells. Immunostaining with anti-Spg antibodies and anti-lacZ antibodies revealed that Spg is localized mainly in R7 photoreceptor cells. Knockdown of spg by the GMR-GAL4 driver reduced signals of R7 photoreceptor cells, suggesting involvement of Spg in R7 cell differentiation. Furthermore, immunostaining with anti-dpERK antibodies showed the level of activated ERK signal was reduced extensively by knockdown of spg in eye discs, and both the defects in eye morphology and dpERK signals were rescued by over-expression of the Drosophila raf gene, a component of the ERK signaling pathway. Furthermore, the Duolink in situ Proximity Ligation Assay method detected interaction signals between Spg and Rap1 in and around the plasma membrane of the eye disc cells. Together, these results indicate Spg positively regulates the ERK pathway that is required for R7 photoreceptor cell differentiation and the regulation is mediated by interaction with Rap1 during development of the compound eye.


Assuntos
Proteínas de Transporte/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila/citologia , Neurogênese/genética , Células Fotorreceptoras de Invertebrados/citologia , Animais , Proteínas de Transporte/genética , Drosophila/genética , Drosophila/metabolismo , Proteínas de Drosophila/genética , Sistema de Sinalização das MAP Quinases , Mutação , Células Fotorreceptoras de Invertebrados/metabolismo , Proteínas rap1 de Ligação ao GTP/metabolismo
5.
Exp Eye Res ; 112: 45-50, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23631845

RESUMO

The Nakano cataract (NCT) is a recessive disorder in the mouse linked to the nct locus on chromosome 16. In this study, we positionally cloned the critical gene in the nct locus. Herein, we report that cataracts in the BALB/c-nct/nct mouse are caused by a hypomorphic mutation in the coproporphyrin oxidase gene (Cpox), encoding the enzyme responsible for catalyzing oxidative decarboxylation of the heme precursor, coproporphyrinogen III, in the heme biosynthetic pathway. BALB/c-nct/nct mice are homozygous for a G to T nucleotide substitution in the Cpox gene, which results in a p.R380L amino acid substitution in the CPOX protein. The CPOX isoform with the p.R380L substitution retained only 15% of the activity of the wild type isoform. BALB/c-nct/nct mice had excessive accumulation of coproporphyrin III in the lens. The NCT phenotype was normalized by the introduction of a wild type Cpox transgene. The mechanisms by which impairment of CPOX leads to lens opacity in the NCT are elusive. However, our data illuminate a hitherto unanticipated involvement of the heme biosynthesis pathway in lens physiology.


Assuntos
Catarata/genética , Coproporfirinogênio Oxidase/genética , Modelos Animais de Doenças , Oftalmopatias Hereditárias/genética , Mutação de Sentido Incorreto , Substituição de Aminoácidos , Animais , Catarata/metabolismo , Coproporfirinogênio Oxidase/metabolismo , Coproporfirinas/metabolismo , Oftalmopatias Hereditárias/metabolismo , Feminino , Heme/metabolismo , Homozigoto , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Mutantes , Camundongos Transgênicos , Fenótipo , Reação em Cadeia da Polimerase , RNA Mensageiro/genética
6.
Cancer Cell ; 4(1): 55-65, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12892713

RESUMO

SPA-1 (signal-induced proliferation-associated gene-1) is a principal Rap1 GTPase-activating protein in hematopoietic progenitors. SPA-1-deficient mice developed a spectrum of myeloid disorders that resembled human chronic myelogenous leukemia (CML) in chronic phase, CML in blast crisis, and myelodysplastic syndrome as well as anemia. Preleukemic SPA-1-deficient mice revealed selective expansion of marrow pluripotential hematopoietic progenitors, which showed abnormal Rap1GTP accumulation. Overexpression of an active form of Rap1 promoted the proliferation of normal hematopoietic progenitors, while SPA-1 overexpression markedly suppressed it. Furthermore, restoring SPA-1 gene in a SPA-1-deficient leukemic blast cell line resulted in the dissolution of Rap1GTP accumulation and concomitant loss of the leukemogenicity in vivo. These results unveiled a role of Rap1 in myeloproliferative stem cell disorders and a tumor suppressor function of SPA-1.


Assuntos
Proteínas Ativadoras de GTPase , Regulação Leucêmica da Expressão Gênica , Células-Tronco Hematopoéticas/metabolismo , Transtornos Mieloproliferativos/genética , Proteínas Nucleares/fisiologia , Proteínas rap1 de Ligação ao GTP/metabolismo , Animais , Crise Blástica/patologia , Células Cultivadas , Feminino , Células-Tronco Hematopoéticas/patologia , Humanos , Masculino , Camundongos , Camundongos Knockout , Camundongos SCID , Transtornos Mieloproliferativos/metabolismo , Transtornos Mieloproliferativos/prevenção & controle
7.
J Exp Med ; 202(12): 1643-8, 2005 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-16352741

RESUMO

Because most autoimmune diseases are polygenic, analysis of the synergistic involvement of various immune regulators is essential for a complete understanding of the molecular pathology of these diseases. We report the regulation of autoimmune diseases by epistatic effects of two immunoinhibitory receptors, low affinity type IIb Fc receptor for IgG (FcgammaRIIB) and programmed cell death 1 (PD-1). Approximately one third of the BALB/c-Fcgr2b(-/-)Pdcd1(-/-) mice developed autoimmune hydronephrosis, which is not observed in either BALB/c-Fcgr2b(-/-) or BALB/c-Pdcd1(-/-) mice. Hydronephrotic mice produced autoantibodies (autoAbs) against urothelial antigens, including uroplakin IIIa, and these antibodies were deposited on the urothelial cells of the urinary bladder. In addition, approximately 15% of the BALB/c-Fcgr2b(-/-)Pdcd1(-/-) mice produced antinuclear autoAbs. In contrast, the frequency of the autoimmune cardiomyopathy and the production of anti-parietal cell autoAb, which were observed in BALB/c-Pdcd1(-/-) mice, were not affected by the additional FcgammaRIIB deficiency. These observations suggest cross talk between two immunoinhibitory receptors, FcgammaRIIB and PD-1, on the regulation of autoimmune diseases.


Assuntos
Antígenos de Superfície/imunologia , Proteínas Reguladoras de Apoptose/imunologia , Autoanticorpos/imunologia , Doenças Autoimunes/imunologia , Hidronefrose/imunologia , Receptor Cross-Talk/imunologia , Receptores de IgG/imunologia , Animais , Antígenos de Superfície/genética , Proteínas Reguladoras de Apoptose/genética , Doenças Autoimunes/genética , Western Blotting , Ensaio de Imunoadsorção Enzimática , Epistasia Genética , Hidronefrose/genética , Hidronefrose/patologia , Imuno-Histoquímica , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Receptor de Morte Celular Programada 1 , Receptores de IgG/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Uroplaquina III
8.
Int Immunol ; 22(6): 443-52, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20410257

RESUMO

The deficiency of programmed cell death 1 (PD-1, Pdcd1), a negative immuno-receptor belonging to the CD28/cytotoxic T lymphocyte antigen 4 (CTLA-4) family, can support various tissue-specific autoimmune conditions. Here, we analyzed the effect of PD-1 deficiency in MRL mice that is genetically predisposed to systemic autoimmunity. MRL-Pdcd1(-)(/-) mice developed a fatal myocarditis, which is reminiscent of CTLA-4-deficient (Ctla4(-)(/-)) mice. Massive infiltration of CD4(+) and CD8(+) T cells and myeloid cells was found in hearts of MRL-Pdcd1(-)(/-) mice concomitant with the production of high-titer auto-antibodies against cardiac myosin. In contrast to Ctla4(-)(/-) mice in which most of the CD4(+) T cells are non-specifically activated and invade various organs, T cells in the heart but not in the spleen and lymph nodes are activated in MRL-Pdcd1(-)(/-) mice, suggesting that myocarditis is mediated by antigen-specific autoimmune response. Heart infiltrating myeloid cells strongly suppressed the allogenic response of T cells in vitro, suggesting that these Mac1(+)Gr1(+) myeloid cells are phenotypically similar to myeloid suppressor cells, which can be found in tumor-bearing hosts. These findings unravel the hidden heart-specific autoimmune predisposition of MRL mice and provide MRL-Pdcd1(-)(/-) mice as a useful animal model of lymphocytic myocarditis.


Assuntos
Antígenos de Diferenciação/genética , Células Mieloides/metabolismo , Miocardite/metabolismo , Linfócitos T/metabolismo , Animais , Antígenos CD/genética , Antígenos de Diferenciação/metabolismo , Autoanticorpos/biossíntese , Autoanticorpos/genética , Autoanticorpos/imunologia , Antígeno CTLA-4 , Miosinas Cardíacas/imunologia , Predisposição Genética para Doença , Tolerância Imunológica , Inflamação , Teste de Cultura Mista de Linfócitos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos MRL lpr , Camundongos Knockout , Células Mieloides/patologia , Miocardite/genética , Miocardite/imunologia , Especificidade de Órgãos , Receptor de Morte Celular Programada 1 , Linfócitos T/patologia
9.
BMC Genet ; 12: 91, 2011 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-22013926

RESUMO

BACKGROUND: Hypohidrotic ectodermal dysplasia (HED) is a congenital disorder characterized by sparse hair, oligodontia, and inability to sweat. It is caused by mutations in any of three Eda pathway genes: ectodysplasin (Eda), Eda receptor (Edar), and Edar-associated death domain (Edaradd), which encode ligand, receptor, and intracellular adaptor molecule, respectively. The Eda signaling pathway activates NF-κB, which is central to ectodermal differentiation. Although the causative genes and the molecular pathway affecting HED have been identified, no curative treatment for HED has been established. Previously, we found a rat spontaneous mutation that caused defects in hair follicles and named it sparse-and-wavy (swh). Here, we have established the swh rat as the first rat model of HED and successfully identified the swh mutation. RESULTS: The swh/swh rat showed sparse hair, abnormal morphology of teeth, and absence of sweat glands. The ectoderm-derived glands, meibomian, preputial, and tongue glands, were absent. We mapped the swh mutation to the most telomeric part of rat Chr 7 and found a Pro153Ser missense mutation in the Edaradd gene. This mutation was located in the death domain of EDARADD, which is crucial for signal transduction and resulted in failure to activate NF-κB. CONCLUSIONS: These findings suggest that swh is a loss-of-function mutation in the rat Edaradd and indicate that the swh/swh rat would be an excellent animal model of HED that could be used to investigate the pathological basis of the disease and the development of new therapies.


Assuntos
Displasia Ectodérmica Hipo-Hidrótica Autossômica Recessiva/genética , Proteína de Domínio de Morte Associada a Edar/genética , Proteína de Domínio de Morte Associada a Edar/metabolismo , NF-kappa B/metabolismo , Animais , Mapeamento Cromossômico , Modelos Animais de Doenças , Displasia Ectodérmica Hipo-Hidrótica Autossômica Recessiva/patologia , Células HEK293 , Humanos , Hipo-Hidrose/genética , Camundongos , Mutação de Sentido Incorreto/genética , NF-kappa B/genética , Ratos , Glândulas Sudoríparas/patologia
10.
Nat Med ; 9(12): 1477-83, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14595408

RESUMO

We recently reported that mice deficient in the programmed cell death-1 (PD-1) immunoinhibitory coreceptor develop autoimmune dilated cardiomyopathy (DCM), with production of high-titer autoantibodies against a heart-specific, 30-kDa protein. In this study, we purified the 30-kDa protein from heart extract and identified it as cardiac troponin I (cTnI), encoded by a gene in which mutations can cause familial hypertrophic cardiomyopathy (HCM). Administration of monoclonal antibodies to cTnI induced dilatation and dysfunction of hearts in wild-type mice. Monoclonal antibodies to cTnI stained the surface of cardiomyocytes and augmented the voltage-dependent L-type Ca2+ current of normal cardiomyocytes. These findings suggest that antibodies to cTnI induce heart dysfunction and dilatation by chronic stimulation of Ca2+ influx in cardiomyocytes.


Assuntos
Antígenos de Superfície/imunologia , Autoanticorpos/metabolismo , Cardiomiopatia Dilatada/etiologia , Cardiomiopatia Dilatada/imunologia , Troponina I/imunologia , Animais , Anticorpos Monoclonais/administração & dosagem , Antígenos CD , Antígenos de Superfície/genética , Proteínas Reguladoras de Apoptose , Sequência de Bases , Sinalização do Cálcio , Cardiomiopatia Dilatada/genética , Cardiomiopatia Dilatada/metabolismo , DNA Complementar/genética , Humanos , Camundongos , Camundongos Endogâmicos A , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Nus , Miócitos Cardíacos/imunologia , Miócitos Cardíacos/metabolismo , Receptor de Morte Celular Programada 1 , Ratos , Ratos Wistar
11.
Nat Med ; 8(7): 738-42, 2002 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12068290

RESUMO

Secretion of gastric inhibitory polypeptide (GIP), a duodenal hormone, is primarily induced by absorption of ingested fat. Here we describe a novel pathway of obesity promotion via GIP. Wild-type mice fed a high-fat diet exhibited both hypersecretion of GIP and extreme visceral and subcutaneous fat deposition with insulin resistance. In contrast, mice lacking the GIP receptor (Gipr(-/-)) fed a high-fat diet were clearly protected from both the obesity and the insulin resistance. Moreover, double-homozygous mice (Gipr(-/-), Lep(ob)/Lep(ob)) generated by crossbreeding Gipr(-/-) and obese ob/ob (Lep(ob)/Lep(ob)) mice gained less weight and had lower adiposity than Lep(ob)/Lep(ob) mice. The Gipr(-/-) mice had a lower respiratory quotient and used fat as the preferred energy substrate, and were thus resistant to obesity. Therefore, GIP directly links overnutrition to obesity and it is a potential target for anti-obesity drugs.


Assuntos
Tecido Adiposo/fisiologia , Polipeptídeo Inibidor Gástrico/fisiologia , Obesidade/prevenção & controle , Receptores dos Hormônios Gastrointestinais/fisiologia , Transdução de Sinais/fisiologia , Tecido Adiposo/anatomia & histologia , Animais , Peso Corporal , Cruzamentos Genéticos , Gorduras na Dieta , Polipeptídeo Inibidor Gástrico/deficiência , Polipeptídeo Inibidor Gástrico/genética , Camundongos , Camundongos Knockout , Receptores dos Hormônios Gastrointestinais/deficiência , Receptores dos Hormônios Gastrointestinais/genética
12.
J Exp Med ; 197(9): 1173-81, 2003 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-12732658

RESUMO

Genome stability is regulated by the balance between efficiencies of the repair machinery and genetic alterations such as mutations and chromosomal rearrangements. It has been postulated that deregulation of class switch recombination (CSR) and somatic hypermutation (SHM), which modify the immunoglobulin (Ig) genes in activated B cells, may be responsible for aberrant chromosomal translocations and mutations of non-Ig genes that lead to lymphocyte malignancy. However, the molecular basis for these genetic instabilities is not clearly understood. Activation-induced cytidine deaminase (AID) is shown to be essential and sufficient to induce both CSR and SHM in artificial substrates in fibroblasts as well as B cells. Here we show that constitutive and ubiquitous expression of AID in transgenic mice caused both T cell lymphomas and dysgenetic lesions of epithelium of respiratory bronchioles (micro-adenomas) in all individual mice. Point mutations, but not translocations, were massively introduced in expressed T cell receptor (TCR) and c-myc genes in T lymphoma cells. The results indicate that AID can mutate non-Ig genes including oncogenes, implying that aberrant AID expression could be a cause of human malignancy.


Assuntos
Transformação Celular Neoplásica , Citidina Desaminase/metabolismo , Animais , Sequência de Bases , Southern Blotting , Primers do DNA , Citometria de Fluxo , Tecido Linfoide/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Camundongos Transgênicos , Mutação Puntual , Receptores de Antígenos de Linfócitos T/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa
13.
Cancer Sci ; 101(3): 800-5, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20353532

RESUMO

While the molecular mechanisms underlying microsatellite instability (MSI) have been exhaustively investigated, identifying the patterns of MSI distribution within diverse cancer genomes has remained an elusive issue. In the present study, we conducted genome-wide MSI screening in B-cell lymphoblastic lymphomas (B-LBL) which spontaneously develop in the SL/Kh strain of mice. Tumor samples harvested from 16 mice were investigated using a framework map consisting of 150 microsatellite markers spaced at increments of roughly 0.5-3.0 centimorgans, spanning the entirety of mouse chromosomes (mus musculus chromosomes [MMU]) 3-6. MMU3 contains a quantitative trait locus (QTL), Bomb1 (bone marrow pre-B1), known to induce an aberrant expansion of pre-B cells in bone marrow prior to the onset of B-LBL in SL/Kh mice. The remaining chromosomes were selected on the basis of those most closely resembling MMU3 in terms of total estimated length (maximum variance 10 Mb). MSI was confirmed at 2

Assuntos
Linfoma de Células B/genética , Instabilidade de Microssatélites , Locos de Características Quantitativas , Animais , Camundongos
14.
Leuk Res ; 32(2): 309-14, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17617450

RESUMO

The pre-B lymphoma in SL/Kh mice is a polygenic trait involving a number of host genes. In prelymphoma-stage bone marrow, transient pre-B cell expansion is induced by a host locus, Bomb1, and later followed by the emergence of a monoclonal population with a similar phenotype. To determine whether these pre-B cells represent precursors of lymphomas, we generated a congenic strain, NFS.SL/Kh-Bomb1 mice, by marker-assisted backcrossing to NFS. The congenic mice showed pre-B cell expansion, but pre-B lymphomas were not observed, even after 1 year of observation, irrespective of murine leukemia virus inoculation. Disturbed early B cell differentiation per se is not sufficient for SL/Kh lymphomagenesis.


Assuntos
Células da Medula Óssea/citologia , Transformação Celular Neoplásica/genética , Linfoma de Células B/genética , Células Precursoras de Linfócitos B/citologia , Animais , Células da Medula Óssea/virologia , Células Clonais , Citometria de Fluxo , Rearranjo Gênico do Linfócito B , Vírus da Leucemia Murina , Linfoma de Células B/virologia , Camundongos , Camundongos Congênicos , Reação em Cadeia da Polimerase , Lesões Pré-Cancerosas/genética , Lesões Pré-Cancerosas/virologia , Células Precursoras de Linfócitos B/virologia
15.
Curr Biol ; 13(4): 333-8, 2003 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-12593800

RESUMO

Notch signaling is involved in the cell fate determination of various cell lineages. Notch interaction with its ligand induces the cleavage of its intracellular domain (IC), and the Notch IC translocates to the nucleus and binds to RBP-J to transactivate transcription of target genes. All four Notches in mammals bind to RBP-J to exert their transactivation activities. Notch is expressed in developing or differentiating epidermis and hairs, inhibits the terminal differentiation of the epidermis, and regulates hair differentiation. The common stem cells that reside in the upper portion of hair follicles (the bulge) contribute to epidermal and hair cell formation. However, it is unknown what determines whether hair follicular stem cells will become hairs or epidermis. Here we report that conditionally disrupting the mouse RBP-J gene in a mosaic pattern to avoid embryonic lethality of RBP-J-deficiency caused hair loss, epidermal hyperkeratinization, and epidermal cyst formation. Cyst formation is probably due to a combination of the aberrant fate determination of RBP-J-deficient stem cells to epidermal progenitors and their accelerated differentiation into epidermis. These results suggest that Notch/RBP-J signaling regulates the cell fate determination of hair follicular stem cells at the bulge region.


Assuntos
Células Epidérmicas , Cabelo/química , Proteínas de Membrana/metabolismo , Transdução de Sinais , Células-Tronco/química , Animais , Linhagem da Célula , Proteínas de Membrana/genética , Camundongos , Mosaicismo , Receptores Notch
16.
Cancer Lett ; 231(2): 185-91, 2006 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-15876484

RESUMO

We previously reported that Dark-Agouti (DA) rats are highly susceptible to 4-nitroquinoline 1-oxide (4NQO)-induced tongue cancer (TC), whereas Wistar/Furth (WF) rats are barely susceptible. Linkage analysis of reciprocal (DAxWF)F2 rats demonstrated five quantitative trait loci, Tongue squamous cell carcinoma 1-5 (Tscc1-5) determining the size and number of the TCs. The major susceptibility locus Tscc1 is mapped on rat chromosome 19. In the present study, we used a marker-assisted speed congenic procedure to construct WF.DA-Tscc1 (WF-T1D) rats, i.e. WF rats carrying a DA-derived Tscc1 chromosomal segment, and evaluated the effect of a single Tscc1 on 4NQO-induced tongue carcinogenesis. In WF-T1D rats, the incidence, number and size of 4NQO-induced TCs were significantly higher than those in WF rats, indicating that the introgressed segment contains one of the susceptibility loci for 4NQO-induced TCs from DA rats. Detection of a single nucleotide polymorphism in NQO1, one of the Tscc1 candidate genes, enabled us to map NQO1 in the Tscc1 segment between D19Wox8 and D19Wox7 on chromosome 19. Possible relevance of NQO1 polymorphism to TC susceptibility is discussed.


Assuntos
Carcinoma de Células Escamosas/genética , Predisposição Genética para Doença , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas , Neoplasias da Língua/genética , 4-Nitroquinolina-1-Óxido/toxicidade , Animais , Carcinógenos/toxicidade , Carcinoma de Células Escamosas/induzido quimicamente , Cromossomos/genética , Feminino , Endogamia , Incidência , Masculino , Ratos , Ratos Endogâmicos WF , Neoplasias da Língua/induzido quimicamente
17.
Clin Cancer Res ; 11(20): 7322-7, 2005 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-16243803

RESUMO

PURPOSE: Human invariant natural killer T (NKT) cells are novel, distinct lymphocyte populations with a restricted T-cell receptor repertoire (Valpha24-Vbeta11). They play a pivotal role in immunoregulation and in antitumor activities. This study focused on Valpha24+ NKT cells in colorectal carcinomas and their clinicopathologic significance. EXPERIMENTAL DESIGN: Valpha24+ NKT-cell infiltration immunohistochemistry was studied in a total of 103 colorectal carcinoma cases. The degree of NKT-cell infiltration in tumors was evaluated as low (<7 NKT cells/5 HPF) or high (> or =7 NKT cells/5 HPF). The correlation between the degree of infiltrated Valpha24+ NKT cells and clinicopathologic variables was studied statistically. RESULTS: A small number of Valpha24+ NKT cells were found in the normal colorectal mucosa (2.6 +/- 3.7 cells/5 HPF); however, their number increased remarkably in colorectal carcinomas (15.2 +/- 16.3 cells/5 HPF; P = 0.0003) and a majority showed phenotype of activation. Higher NKT-cell infiltration was more frequent in women than in men (P = 0.034) and correlated with fewer lymph node metastases (P = 0.042). Patients with high NKT-cell infiltration showed higher overall (P = 0.018) as well as disease-free (P = 0.0006) survival rates. Intratumor NKT-cell infiltration was an independent prognostic factor for the overall (P = 0.033) and disease-free (P = 0.0064) survival rates. CONCLUSIONS: Increased infiltration of Valpha24+ NKT cells was observed in colorectal carcinomas. Higher Valpha24+ NKT-cell infiltration in colorectal carcinomas was an independent prognostic factor for favorable prognosis.


Assuntos
Neoplasias Colorretais/patologia , Células Matadoras Naturais/patologia , Receptores de Antígenos de Linfócitos T alfa-beta/análise , Idoso , Antígenos de Superfície/análise , Antígeno CD56/análise , Antígenos CD57/análise , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/mortalidade , Feminino , Humanos , Imuno-Histoquímica/métodos , Células Matadoras Naturais/imunologia , Lectinas Tipo C/análise , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Subfamília B de Receptores Semelhantes a Lectina de Células NK , Prognóstico , Análise de Sobrevida , Taxa de Sobrevida
18.
Exp Anim ; 55(2): 91-5, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16651691

RESUMO

Increasing exposure to environmental endocrine disruptor, xeno-estrogen, is a serious hazard to male reproductive activity. To explore possible genetic control in susceptibility to xeno-estrogen, the weight reduction of testes induced by the continuous administration of a synthetic estrogen, diethylstilbesterol, were investigated by quantitative trait analysis in LEXF and FXLE recombinant inbred strain rats, consisting of 21 independent strains, 9 of their substrains, parental F344/Stm and LE/Stm strains, and (F344 x LE)F1. For the weight of testes, one highly significant quantitative trait locus (QTL) and one significant QTL were mapped on chromosomes 7 and 1, respectively. The QTL on chromosome 7 is closely associated with c-myc. Pituitary weight and serum prolactin were also variable among recombinant inbred strains, but no QTL was detected for them in this study.


Assuntos
Dietilestilbestrol/toxicidade , Hipófise/efeitos dos fármacos , Ratos Endogâmicos/genética , Testículo/efeitos dos fármacos , Animais , Mapeamento Cromossômico , Disruptores Endócrinos/toxicidade , Masculino , Tamanho do Órgão/efeitos dos fármacos , Prolactina/sangue , Ratos , Recombinação Genética
19.
Exp Hematol ; 33(6): 641-51, 2005 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-15911088

RESUMO

OBJECTIVE: The LIM-finger protein LMO2 forms a transcription factor complex with other hematopoietic regulator proteins, such as TAL1 (SCL), LDB1, GATA1, 2, and 3, in the promoters of several erythroid genes. To elucidate the functional role of two LIM domains in LMO2, we introduced deletion or mutation in each of the LIM domains and analyzed their phenotypic effects on the hematopoietic system when overexpressed in vivo or in vitro. MATERIALS AND METHODS: Protein interactions of LIM-modified LMO2 constructs with TAL1, LDB1, and GATAs were examined in an immunoprecipitation assay. In vivo hematopoiesis in transgenic mice with wild-type and LIM-modified Lmo2 was studied morphologically and by measuring the progenitor cells in fetal liver. Their effects on the erythroid differentiation of the dimethylsulfoxide (DMSO)-induced murine erythroleukemia (MEL) cells were evaluated. RESULTS: Deletion of the LIM2 domain, but not of the LIM1 domain, abolished its binding of GATA proteins. Overexpression of wild-type LMO2 is known to have dominant negative inhibitory effects on erythropoietic development. Enforced expression of LMO2 constructs with mutant or absent LIM2 but with an intact LIM1 domain resulted in fetal death, small livers and hearts, and decreased hematopoiesis, as well as a hypoplastic thymus. DMSO-induced erythroid differentiation of the MEL cells was inhibited by the overexpressed LMO2 with mutant LIM2 but not by the LMO2 with modified LIM1. CONCLUSION: Overexpression of the LMO2 with modified LIM2 inhibited hematopoiesis probably by interfering with the formation of the physiological complex or by replacing the functional LMO2 with mutants with reduced affinity to GATA proteins. In this experiment, no evident effect of the LMO2 with modified LIM1 could be observed.


Assuntos
Proteínas de Ligação a DNA/genética , Hematopoese Extramedular , Fígado/fisiologia , Metaloproteínas/genética , Mutação , Transcrição Gênica , Proteínas Adaptadoras de Transdução de Sinal , Animais , Sequência de Bases , Diferenciação Celular , Linhagem Celular Tumoral , Primers do DNA , Imunoprecipitação , Proteínas com Domínio LIM , Camundongos , Mutagênese Sítio-Dirigida
20.
J Clin Invest ; 126(4): 1367-82, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26974156

RESUMO

Most skin cancers develop as the result of UV light-induced DNA damage; however, a substantial number of cases appear to occur independently of UV damage. A causal link between UV-independent skin cancers and chronic inflammation has been suspected, although the precise mechanism underlying this association is unclear. Here, we have proposed that activation-induced cytidine deaminase (AID, encoded by AICDA) links chronic inflammation and skin cancer. We demonstrated that Tg mice expressing AID in the skin spontaneously developed skin squamous cell carcinoma with Hras and Trp53 mutations. Furthermore, genetic deletion of Aicda reduced tumor incidence in a murine model of chemical-induced skin carcinogenesis. AID was expressed in human primary keratinocytes in an inflammatory stimulus-dependent manner and was detectable in human skin cancers. Together, the results of this study indicate that inflammation-induced AID expression promotes skin cancer development independently of UV damage and suggest AID as a potential target for skin cancer therapeutics.


Assuntos
Carcinoma de Células Escamosas/enzimologia , Citidina Desaminase/metabolismo , Neoplasias Experimentais/enzimologia , Neoplasias Cutâneas/enzimologia , Pele/enzimologia , Raios Ultravioleta/efeitos adversos , Animais , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patologia , Citidina Desaminase/genética , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Camundongos Nus , Mutação , Neoplasias Experimentais/genética , Neoplasias Experimentais/patologia , Especificidade de Órgãos , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Pele/patologia , Neoplasias Cutâneas/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo
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