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1.
Sci Rep ; 11(1): 13109, 2021 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-34162906

RESUMO

Breastfeeding influences the immune system development in infants and may even affect various immunological responses later in life. Breast milk provides a rich source of early nutrition for infant growth and development. However, the presence of certain compounds in breast milk, related to an unhealthy lifestyle or the diet of lactating mothers, may negatively impact infants. Based on a cohort study of atopic dermatitis (AD), we find the presence of damage-associated molecular patterns (DAMPs) activity in the mother's milk. By non-targeted metabolomic analysis, we identify the long-chain saturated fatty acids (LCSFA) as a biomarker DAMPs (+) breast milk samples. Similarly, a mouse model in which breastfed offspring are fed milk high in LCSFA show AD onset later in life. We prove that LCSFA are a type of damage-associated molecular patterns, which initiate a series of inflammatory events in the gut involving type 3 innate lymphoid cells (ILC3s). A remarkable increase in inflammatory ILC3s is observed in the gut, and the migration of these ILC3s to the skin may be potential triggers of AD. Gene expression analysis of ILC3s isolated from the gut reveal upregulation of genes that increase ILC3s and chemokines/chemokine receptors, which may play a role in ILC migration to the skin. Even in the absence of adaptive immunity, Rag1 knockout mice fed a high-LCSFA milk diet develop eczema, accompanied by increased gut ILC3s. We also present that gut microbiota of AD-prone PA milk-fed mice is different from non-AD OA/ND milk-fed mice. Here, we propose that early exposure to LCSFAs in infants may affect the balance of intestinal innate immunity, inducing a highly inflammatory environment with the proliferation of ILC3s and production of interleukin-17 and interleukin-22, these factors may be potential triggers or worsening factors of AD.


Assuntos
Dermatite Atópica/etiologia , Ácidos Graxos/análise , Leite Humano/química , Leite/química , Alarminas/análise , Alarminas/imunologia , Animais , Dermatite Atópica/patologia , Modelos Animais de Doenças , Ácidos Graxos/imunologia , Feminino , Interleucina-17/metabolismo , Interleucinas/metabolismo , Masculino , Metabolômica , Camundongos , Leite/imunologia , Leite Humano/imunologia , Estudos Prospectivos , Pele/imunologia , Pele/metabolismo , Interleucina 22
2.
Tohoku J Exp Med ; 245(3): 193-204, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-30033950

RESUMO

Immunoparalysis is a common cause of death for critical care patients with sepsis, during which comprehensive suppression of innate and adaptive immunity plays a significant pathophysiological role. Although the underlying mechanisms are unknown, damage-associated molecular patterns (DAMPs) from septic tissues might be involved. Therefore, we surveyed sera from septic patients for factors that suppress the innate immune response to DAMPs, including adenosine triphosphate (ATP), monosodium urate, and high mobility group box-1. Macrophages, derived from THP-1 human acute monocytic leukemia cells, were incubated with each DAMP, in the presence or absence of sera that were collected from critically ill patients. Secreted cytokines were then quantified, and cell lysates were assayed for relevant intracellular signaling mediators. Sera from septic patients who ultimately did not survive significantly suppressed IL-1ß production only in response to extracellular ATP. This effect was most pronounced with sera collected on day 3, and persisted with sera collected on day 7. However, this effect was not observed when THP-1 cells were treated with sera from survivors of sepsis. Septic sera collected at the time of admission (day 1) also diminished intracellular levels of inositol 1,4,5-triphosphate and cytosolic calcium (P < 0.01), both of which are essential for ATP signaling. Finally, activated caspase-1 was significantly diminished in cells exposed to sera collected on day 7 (P < 0.05). In conclusion, the sera of septic patients contain certain factors that persistently suppress the immune response to extracellular ATP, thereby leading to adverse clinical outcomes.


Assuntos
Trifosfato de Adenosina/sangue , Espaço Extracelular/metabolismo , Inflamassomos/sangue , Sepse/sangue , Adenosina Trifosfatases/metabolismo , Idoso , Alarminas/metabolismo , Estudos de Casos e Controles , Caspase 1/metabolismo , Quimiocinas/sangue , Estudos de Coortes , Ativação Enzimática , Feminino , Humanos , Inflamação/sangue , Interleucina-1beta/biossíntese , Macrófagos/enzimologia , Macrófagos/patologia , Masculino , Receptores Purinérgicos P2X7/metabolismo , Transdução de Sinais
3.
Arthritis Res Ther ; 17: 275, 2015 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-26419626

RESUMO

INTRODUCTION: Proto-oncogene survivin is a member of the inhibitor of apoptosis (IAP) family of proteins. The presence of serous antibodies against survivin in patients with systemic sclerosis has been previously reported; however, there are few reports regarding the pathophysiological relationship between survivin and systemic sclerosis. We herein investigated the expression and function of survivin in SSc patients. METHODS: We performed immunohistochemistry analyses to determine the expression of XIAP, cIAP and survivin in skin lesions from patients with SSc and non-SSc. The expression levels of survivin in peripheral blood mononuclear cells (PBMCs) obtained from SSc patients and healthy controls were evaluated using RT-PCR and flow cytometry. Additionally, the function of survivin was verified with overexpression experiments using monocyte-derived dendritic cells (Mo-DCs). RESULTS: The expression patterns of both XIAP and cIAP were similar, while only the survivin expression differed between the SSc and non-SSc skin lesions. Survivin-overexpressing cells were detected in the SSc dermis frequently. The positive rate of survivin in SSc dermis (64.3%, 9/14) was higher than that in non-SSc dermis (11.2%, 1/9). Furthermore, survivin+ cells expressed CD1a, one of the DC markers. Real-time PCR and FACS analyses revealed that the survivin-WT (wild type) expression levels in PBMCs, in particular CD14+ monocytes, from SSc patients were higher than that from healthy controls. Additionally, the overexpression experiments showed that survivin-WT-overexpressing CD1a+ Mo-DCs have the characteristics of promoting cell cycle progression and decreasing apoptotic cells. CONCLUSIONS: These findings suggest that dermal survivin+ CD1a+ cell infiltration may be a potential biomarker of SSc skin lesions. PBMCs and monocytes from SSc patients also overexpressed survivin; therefore, dermal survivin+ DC may be derived from peripheral blood monocytes. Additionally, survivin may be involved in dermal CD1a+ DC proliferation through cell cycle activation and resistance to apoptosis. Survivin may be an important molecule for the pathogenesis of SSc.


Assuntos
Antígenos CD1/imunologia , Células Dendríticas/imunologia , Derme/imunologia , Proteínas Inibidoras de Apoptose/imunologia , Escleroderma Sistêmico/imunologia , Adulto , Idoso , Antígenos CD1/genética , Antígenos CD1/metabolismo , Western Blotting , Células Cultivadas , Células Dendríticas/metabolismo , Derme/metabolismo , Derme/patologia , Feminino , Expressão Gênica/imunologia , Humanos , Imuno-Histoquímica , Proteínas Inibidoras de Apoptose/genética , Proteínas Inibidoras de Apoptose/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Masculino , Microscopia Confocal , Pessoa de Meia-Idade , Proto-Oncogene Mas , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Escleroderma Sistêmico/metabolismo , Survivina , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/genética , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/imunologia , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo
4.
Sci Rep ; 5: 9795, 2015 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-25997820

RESUMO

Survivin is an independent prognostic factor for joint destruction in rheumatoid arthritis (RA). However, the expression and function of survivin in RA synoviocytes remain unclear. We certified the expression of survivin in RA synovial tissues and performed the experiment using RA fibroblast-like synoviocytes (RA-FLS) treated with siRNA. As a result, the expression levels of wild type (WT) survivin and the 2B splice variants in RA synovial tissues were higher than those in osteoarthritis tissue samples, and, these variants were highly expressed in RA-FLS. The expression levels of survivin-WT and -2B in the RA-FLS were upregulated by PDGF. Treatment with siRNA against survivin-2B led to decreased viability of PDGF-treated RA-FLS due to cell cycle suppression and apoptosis promotion, while the siRNA against all survivin isoforms did not affect the viability. Moreover, an overexpression of survivin-2B in RA-FLS led to cell proliferation through cell cycle activation and by conferring resistance to apoptosis. In conclusion, survivin-2B has an important role in RA-FLS proliferation. These data suggest that survivin-2B might contribute to rheumatoid synovial hyperplasia, and have the potential as a novel therapeutic target for RA.


Assuntos
Proliferação de Células/efeitos dos fármacos , Proteínas Inibidoras de Apoptose/metabolismo , Proteínas Proto-Oncogênicas c-sis/farmacologia , Membrana Sinovial/metabolismo , Idoso , Apoptose/efeitos dos fármacos , Artrite Reumatoide/metabolismo , Artrite Reumatoide/patologia , Becaplermina , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Feminino , Fibroblastos/citologia , Humanos , Proteínas Inibidoras de Apoptose/antagonistas & inibidores , Proteínas Inibidoras de Apoptose/genética , Interleucina-1beta/metabolismo , Leptina/metabolismo , Masculino , Pessoa de Meia-Idade , Osteoartrite/metabolismo , Osteoartrite/patologia , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proto-Oncogene Mas , Splicing de RNA , RNA Interferente Pequeno/metabolismo , Survivina , Membrana Sinovial/citologia , Membrana Sinovial/efeitos dos fármacos , Fator de Necrose Tumoral alfa/metabolismo
6.
SAGE Open Med Case Rep ; 2: 2050313X13519774, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-27489636

RESUMO

Chronic tophaceous gout is the end stage of gout. We employed a blockade of interleukin-6 signaling therapy by tocilizumab instead of anakinra, an interleukin-1 receptor antagonist, for a 61-year-old Japanese woman diagnosed with tophaceous gout. Laboratory data showed that serum interleukin-6 concentration was elevated. Serum interleukin-1ß concentration was under the detectable level, although serum uric acid was elevated due to renal dysfunction. The secretion patterns of interleukin-1ß, tumor-necrosis factor-α, interleukin-6, and interleukin-8 from peripheral mononuclear cells isolated from the patient exhibited no remarkable differences compared with those of healthy volunteers. After treatment with the interleukin-6 receptor antagonist tocilizumab, serum interleukin-6 concentration decreased followed by improved clinical symptoms, such as reduced size of the subcutaneous nodules, no fever, and no acute gouty attacks during the treatment. Our case suggests that tocilizumab markedly improves clinical and laboratory manifestations in tophaceous gout with arthritis and fever as well as interleukin-1 blockade therapy.

7.
J Biol Chem ; 288(19): 13269-77, 2013 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-23536184

RESUMO

BACKGROUND: It is unclear how DNA-damaging agents target cancer cells over normal somatic cells. RESULTS: Arf/p53-dependent down-regulation of H2AX enables normal cells to survive after DNA damage. CONCLUSION: Transformed cells, which harbor mutations in either Arf or p53, are more sensitive to DNA-damaging agents. SIGNIFICANCE: Cellular transformation renders cells more susceptible to some DNA-damaging agents. Anti-cancer drugs generally target cancer cells rather than normal somatic cells. However, the factors that determine this differential sensitivity are poorly understood. Here we show that Arf/p53-dependent down-regulation of H2AX induced the selective survival of normal cells after drug treatment, resulting in the preferential targeting of cancer cells. Treatment with camptothecin, a topoisomerase I inhibitor, caused normal cells to down-regulate H2AX and become quiescent, a process mediated by both Arf and p53. In contrast, transformed cells that harbor mutations in either Arf or p53 do not down-regulate H2AX and are more sensitive to drugs unless they have developed drug resistance. Such transformation-associated changes in H2AX expression rendered cancer cells more susceptible to drug-induced damage (by two orders of magnitude). Thus, the expression of H2AX and γH2AX (phosphorylated form of H2AX at Ser-139) is a critical factor that determines drug sensitivity and should be considered when administering chemotherapy.


Assuntos
Antineoplásicos/farmacologia , Apoptose , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Regulação para Baixo , Histonas/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Animais , Camptotecina/farmacologia , Forma Celular , Células Cultivadas , Senescência Celular , Cisplatino/farmacologia , Inibidor p16 de Quinase Dependente de Ciclina/genética , Dano ao DNA , Replicação do DNA/efeitos dos fármacos , Doxorrubicina/farmacologia , Resistencia a Medicamentos Antineoplásicos , Técnicas de Silenciamento de Genes , Histonas/genética , Humanos , Hidroxiureia/farmacologia , Camundongos , Camundongos Knockout , Mutação , Fenantrenos/farmacologia , Poli(ADP-Ribose) Polimerase-1 , Inibidores de Poli(ADP-Ribose) Polimerases , Proteína Supressora de Tumor p53/genética
8.
Biochem Biophys Res Commun ; 432(1): 34-9, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23376716

RESUMO

Normal cells undergo a growth-arrested status that is produced by p53-dependent down-regulation of histone H2AX. Immortality is developed after abrogation of the H2AX-diminished state, which is associated with genomic instability (often with tetraploidy) and the induction of mutations in either the Arf or p53 gene. However, the role of Arf in control of H2AX expression and genome stability is still unclear. Here, we show that both Arf and p53 are required for the down-regulation of H2AX and formation of the growth-arrested state. Wild-type (WT) mouse embryonic fibroblasts (MEFs) subjected to tetraploidization with DNA lesions did not undergo mitotic catastrophe-associated cell death and stayed in a growth-arrested state, until immortality was attained with mutations in the Arf/p53 module and recovery of H2AX expression. Whereas tetraploidization was essential for immortalization of WT MEFs, this event was not required for immortalization of MEFs containing mutations in Arf/p53 and these cells still underwent mitotic catastrophe-associated cell death. Thus, WT MEFs are protected from immortalization with genome stability, which is abrogated with tetraploidization and mutation of either Arf or p53.


Assuntos
Pontos de Checagem do Ciclo Celular , Inibidor p16 de Quinase Dependente de Ciclina/fisiologia , Diploide , Instabilidade Genômica , Tetraploidia , Proteína Supressora de Tumor p53/fisiologia , Células 3T3 , Animais , Inibidor p16 de Quinase Dependente de Ciclina/genética , Histonas/metabolismo , Camundongos , Camundongos Knockout , Mitose , Proteína Supressora de Tumor p53/genética
9.
Pathobiology ; 79(4): 209-18, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22508441

RESUMO

A functional methyl group donor is essential for the epigenetic regulation of all biological events due to the importance of DNA methylation and histone methylation as an epigenetic marker. However, the epigenetic alterations in the immune system due to methyl donor deficiency are not well known. In this study, we tried to address this question by studying the lymphocyte development and DNA methylation changes caused by a methyl-deficient diet (MDD). We fed one group of C57BL/6J mice with a methyl-sufficient diet (MSD) and the other group with an MDD for 5 months. Flow cytometry analyses of their immune systems showed a decrease in B220+ IgM+ (immature B) cells and an increase in B220+ IgM- (pro/pre-B) cells in the bone marrow of mice fed an MDD. By means of an in vitro OP9 coculture system, we recognized that this B220+ IgM- cell fraction from the MDD has an intrinsic developmental defect. When we quantitatively measured the mRNA expression levels of transcription factors and recombination machinery related to B cell development in the B220+ IgM- cell fraction of their bone marrow, we found that ADA, EBF1, DNTT and Pax5 mRNA expression levels were significantly downregulated in mice fed with an MDD. In addition, there was a drastic decrease in histone methylation profile H3K4me3 in the Pax5 and EBF1 promoters in these B220+ IgM- B cells. However, CpG-DNA methylation profiles had not changed and this revealed that these two promoters are demethylated even under an MSD condition. We also found changed expression levels of the Polycomb group genes (mel18, bmi1, Pc1, Pc2, Ring1A, Ring1B, Ph1) on semi-quantitative RT-PCR. These results indicate that under an MDD condition, early B cell development in bone marrow is easily affected by epigenetic alterations.


Assuntos
Linfócitos B/citologia , Células da Medula Óssea/citologia , Metilação de DNA , Sistema Imunitário/citologia , Células Precursoras de Linfócitos B/citologia , Animais , Linfócitos B/metabolismo , Células da Medula Óssea/metabolismo , Técnicas de Cocultura , Ilhas de CpG , Dieta , Feminino , Sistema Imunitário/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Células Precursoras de Linfócitos B/metabolismo
10.
Hiroshima J Med Sci ; 60(2): 25-35, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21970185

RESUMO

Side population (SP) cell analysis has been used to identify and isolate a minor population of cells with stem cell properties in normal tissues and in many cancers including breast cancer cells. However, the molecular mechanisms that operate in tumor-initiating cells (TICs) in SP fraction remain unclear. The Polycomb group genes, including Bmi1 and Mel-18, have been implicated in the maintenance of hematopoietic stem cells (HSCs) and suggested to be oncogenic and tumor suppressive, respectively, in breast cancer. In this study, we determined the critical role of Mel-18 in the enrichment mechanisms of TICs with the SP phenotype in a mouse breast cancer cell line, MMK3, that was established from a breast cancer developed spontaneously in Mel-18+/- mice. The Mel-18 protein expression level significantly correlates to the percentage of SP fraction in the mouse breast cancer cell line MMK3 series. The comparison between MMK3V3 (V3) cells containing one copy of the Mel-18 gene and MMK3S2 (S2) cells having twice the amount of Mel-18 expression clearly demonstrates the above relationship. Similar results obtained with the percentage of ALDH+ cells in V3 and S2 further confirmed the correlation between protein expression level of Mel-18 and the TICs. More importantly, transplantation of SP and non-SP cells of V3 and S2 cells into the NOD/SCID mice clearly showed that the heterozygous level of Mel-18 leads to the disappearance of enrichment of TICs into SP fraction in vivo. Stem cell pathway focused gene expression profiling of V3 and S2 cells revealed that the genes Abcg2, Aldh1a1 and Dhh were highly down-regulated in V3 compared to S2. These results indicate that the precise Mel-18 expression level controls TIC enrichment mechanisms through the regulation of channel molecule of Abcg2 and functional TIC marker of Aldhlal. In conclusion, our findings revealed the significance of fine-tuning mechanisms for Mel-18 protein expression level in the maintenance of TIC into SP fractions in mouse breast cancer.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Neoplasias Mamárias Animais/metabolismo , Células-Tronco Neoplásicas/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Aldeído Desidrogenase/genética , Aldeído Desidrogenase/metabolismo , Família Aldeído Desidrogenase 1 , Animais , Linhagem Celular Tumoral , Proliferação de Células , Proteínas de Ligação a DNA/deficiência , Proteínas de Ligação a DNA/genética , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Proteínas Hedgehog/genética , Heterozigoto , Neoplasias Mamárias Animais/genética , Neoplasias Mamárias Animais/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Células-Tronco Neoplásicas/patologia , Complexo Repressor Polycomb 1 , Retinal Desidrogenase , Transfecção
11.
Eur J Immunol ; 41(4): 1098-107, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21400497

RESUMO

Polycomb group gene Bmi1 plays an essential role in HSCs and the BM microenvironment. Recent reports also pointed to the importance of Bmi1 in thymocyte development. However, little is known about its role in the development of the thymic microenvironment. Here, we examined the function of Bmi1 in thymic epithelial cells (TECs) by using the engraftment of fetal thymus (FT) lobes under the kidney capsule. The engrafted Bmi1(-/-) FT lobes were clearly smaller and the number of thymocytes in these lobes was significantly decreased compared with control FT lobes. Analysis of the cell cycle status of TECs in the reconstituted lobes revealed that the reduction of thymus size in Bmi1(-/-) FT grafts was caused by less proliferation of TECs during the early expansion stage. Unlike cases with hematopoietic stem cells or thymocytes, the deletion of p16Ink4a and p19Arf could not restore the defects in Bmi1(-/-) TEC, indicating a distinct role for Bmi1 in TECs. In conclusion, epigenetic regulator polycomb group gene Bmi1 plays a role in the thymic microenvironment in a regeneration process by supporting TEC growth, and thereby contributes to the control of thymus size for T-cell growth in mice.


Assuntos
Proliferação de Células , Células Epiteliais/citologia , Células Epiteliais/imunologia , Proteínas Nucleares/imunologia , Proteínas Proto-Oncogênicas/imunologia , Proteínas Repressoras/imunologia , Timo/citologia , Timo/imunologia , Animais , Células Cultivadas , Inibidor p16 de Quinase Dependente de Ciclina/imunologia , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Células Epiteliais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Nucleares/deficiência , Proteínas Nucleares/metabolismo , Complexo Repressor Polycomb 1 , Proteínas do Grupo Polycomb , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Repressoras/deficiência , Proteínas Repressoras/metabolismo , Transdução de Sinais , Timo/crescimento & desenvolvimento , Timo/metabolismo
12.
J Immunol ; 185(12): 7330-9, 2010 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-21057086

RESUMO

Naturally occurring regulatory T (Treg) cells play a central role in the maintenance of immune homeostasis and in restraining the development of spontaneous inflammatory responses. However, the underlying mechanisms of Treg homeostasis remain incompletely understood. Of particular note, the IL-2Rα (CD25) is crucial for the homeostasis of Treg cells and the prevention of lymphoproliferative autoimmune disease. In this paper, we report that the basic helix-loop-helix transcription factor Dec1 is involved in the homeostasis of Treg cells and plays a role in their survival or expansion after adoptive transfer to lymphopenic recipients. Hence, it is crucial for the suppression of effector T cell-mediated inflammatory responses. Enforced expression of Dec1 upregulates CD25 expression during thymocyte development and increases the number of Treg cells in the periphery. Dec1 binds the transcription factor Runx1 and colocalizes with Runx1 in Treg cells. Specifically, we demonstrate that in Treg cells the Dec1/Runx1 complex binds to regulatory elements present in the Il-2rα locus. Collectively, these data show how Dec1 mechanistically acts in Treg cells.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/imunologia , Proteínas de Homeodomínio/imunologia , Homeostase/fisiologia , Subunidade alfa de Receptor de Interleucina-2/imunologia , Regulação para Cima/fisiologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Sobrevivência Celular/fisiologia , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/imunologia , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Subunidade alfa de Receptor de Interleucina-2/genética , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Camundongos , Camundongos Transgênicos , Ligação Proteica/genética , Ligação Proteica/imunologia , Linfócitos T Reguladores
13.
Dev Biol ; 345(2): 226-36, 2010 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-20647008

RESUMO

Although internal ribosome entry site (IRES)-mediated translation is considered important for proper cellular function, its precise biological role is not fully understood. Runx1 gene, which encodes a transcription factor implicated in hematopoiesis, angiogenesis, and leukemogenesis, contains IRES sequences in the 5' untranslated region. To clarify the roles of the IRES element in Runx1 function, we generated knock-in mice for either wild-type Runx1 or Runx1/Evi1, a Runx1 fusion protein identified in human leukemia. In both cases, native promoter-dependent transcription was retained, whereas IRES-mediated translation was eliminated. Interestingly, homozygotes expressing wild-type Runx1 deleted for the IRES element (Runx1(Delta IRES/Delta IRES)) died in utero with prominent dilatation of peripheral blood vessels due to impaired pericyte development. In addition, hematopoietic cells in the Runx1(Delta IRES/Delta IRES) fetal liver were significantly decreased, and exhibited an altered differentiation pattern, a reduced proliferative activity, and an impaired reconstitution ability. On the other hand, heterozygotes expressing Runx1/Evi1 deleted for the IRES element (Runx1(+/RE Delta IRES)) were born normally and did not show any hematological abnormalities, in contrast that conventional Runx1/Evi1 heterozygotes die in utero with central nervous system hemorrhage and Runx1/Evi1 chimeric mice develop acute leukemia. The findings reported here demonstrate the essential roles of the IRES element in Runx1 function under physiological and pathological conditions.


Assuntos
Regiões 5' não Traduzidas , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Hematopoese/genética , Leucemia/genética , Neovascularização Fisiológica/genética , Animais , Diferenciação Celular , Regulação Leucêmica da Expressão Gênica , Técnicas de Introdução de Genes , Heterozigoto , Fígado/patologia , Camundongos , Modelos Animais , Ribossomos/metabolismo
14.
Cancer Sci ; 99(6): 1077-84, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18422744

RESUMO

The chromatin-associated Polycomb group (PcG) proteins were first identified in genetic screens for homeotic transformations in Drosophila melanogaster. Besides body patterning, members of the PcG are now known to regulate epigenetic cellular memory, stem cell self-renewal, and cancer development. Here, we discuss the multifarious functions of the PcG family, isoforms of protein complexes, and its enzymatic activities, for example histone methylation, links to DNA methylation, its phosphorylation status, H2A mono-ubiquitination, SUMOylation, and links to non-coding RNA. We also discuss the function of cytosolic PcG complexes as a regulator of receptor-induced actin polymerization and proliferation in a methylation-dependent manner. We propose that the functional versatility of PcG protein complexes contributed significantly to the complexity of heritable gene repression mechanisms, signal transduction, and cell proliferation in cancer development.


Assuntos
Diferenciação Celular , Epigênese Genética/genética , Neoplasias/genética , Proteínas Repressoras/genética , Animais , Humanos , Proteínas do Grupo Polycomb
15.
Immunity ; 28(2): 231-45, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18275833

RESUMO

Thymocytes undergo massive proliferation before T cell receptor (TCR) gene rearrangement, ensuring the diversification of the TCR repertoire. Because activated cells are more susceptible to damage, cell-death restraint as well as promotion of cell-cycle progression is considered important for adequate cell growth. Although the molecular mechanism of pre-TCR-induced proliferation has been examined, the mechanisms of protection against cell death during the proliferation phase remain unknown. Here we show that the survival of activated pre-T cells induced by pre-TCR signaling required the Polycomb group (PcG) gene product Bmi-1-mediated repression of Cdkn2A, and that p19Arf expression resulted in thymocyte cell death and inhibited the transition from CD4(-)CD8(-) (DN) to CD4(+)CD8(+) (DP) stage upstream of the transcriptional factor p53 pathway. The expression of Cdkn2A (the gene encoding p19Arf) in immature thymocytes was directly regulated by PcG complex containing Bmi-1 and M33 through the maintenance of local trimethylated histone H3K27. Our results indicate that this epigenetic regulation critically contributes to the survival of the activated pre-T cells, thereby supporting their proliferation during the DN-DP transition.


Assuntos
Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Genes p16/fisiologia , Proteínas Nucleares/metabolismo , Oxirredutases N-Desmetilantes/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Repressoras/metabolismo , Linfócitos T/imunologia , Linfócitos T/fisiologia , Animais , Diferenciação Celular , Proliferação de Células , Sobrevivência Celular , Inibidor p16 de Quinase Dependente de Ciclina/deficiência , Inibidor p16 de Quinase Dependente de Ciclina/genética , Inibidor p16 de Quinase Dependente de Ciclina/imunologia , Epigênese Genética , Histona Desmetilases com o Domínio Jumonji , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Proteínas Nucleares/deficiência , Proteínas Nucleares/genética , Proteínas Nucleares/imunologia , Oxirredutases N-Desmetilantes/imunologia , Complexo Repressor Polycomb 1 , Proteínas Proto-Oncogênicas/deficiência , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Receptores de Antígenos de Linfócitos T/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/imunologia , Transdução de Sinais , Linfócitos T/citologia , Linfócitos T/metabolismo , Proteína Supressora de Tumor p53/imunologia , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima
17.
Pathobiology ; 74(3): 177-85, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17643063

RESUMO

OBJECTIVE: The danger hypothesis proposes that the immune system responds not only to foreign antigens but also to damaged cells or tissues. Recently, uric acid crystals (monosodium urate, MSU) from necrotic cell lysates were identified as a danger signal for dendritic cells (DCs). Our aim was to determine whether MSU modulates immune responses in the skin. METHOD: We analyzed the effect of MSU on trinitrochlorobenzene-induced contact hypersensitivity responses using BALB/c mice administered potassium oxonate, an uricase inhibitor, to prevent MSU degradation. Ear swelling response after elicitation and activation profiles of DCs and T cells in draining lymph nodes after sensitization were assessed. RESULTS: Intradermal administration of MSU augmented the ear swelling response in potassium oxonate-administered mice and enhanced expression of CD86 and CD40 molecules on DCs in the lymph nodes. Activation of DCs was followed by an increase in CD69+ and CD44+ T cells in CD4+ and/or CD8+ subsets in the lymph nodes 4 days after trinitrochlorobenzene sensitization. CONCLUSION: These observations demonstrate that MSU is an endogenous danger signal, which augments the contact hypersensitivity response in mice. MSU released from damaged skin may act as an endogenous adjuvant to augment immune response.


Assuntos
Clorobenzenos/imunologia , Dermatite de Contato/imunologia , Transdução de Sinais/imunologia , Ácido Úrico/imunologia , Animais , Antígeno B7-2/metabolismo , Antígenos CD40/metabolismo , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Dermatite de Contato/metabolismo , Dermatite de Contato/patologia , Sinergismo Farmacológico , Orelha Externa/efeitos dos fármacos , Orelha Externa/imunologia , Orelha Externa/patologia , Edema/induzido quimicamente , Edema/imunologia , Edema/patologia , Imunidade Celular , Injeções Subcutâneas , Linfonodos/efeitos dos fármacos , Linfonodos/imunologia , Linfonodos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Ácido Oxônico/farmacologia , Subpopulações de Linfócitos T/efeitos dos fármacos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Ácido Úrico/sangue
18.
PLoS Biol ; 4(4): e103, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16509771

RESUMO

The IAN (immune-associated nucleotide-binding protein) family is a family of functionally uncharacterized GTP-binding proteins expressed in vertebrate immune cells and in plant cells during antibacterial responses. Here we show that all eight IAN family genes encoded in a single cluster of mouse genome are predominantly expressed in lymphocytes, and that the expression of IAN1, IAN4, and IAN5 is significantly elevated upon thymic selection of T lymphocytes. Gain-of-function experiments show that the premature overexpression of IAN1 kills immature thymocytes, whereas short hairpin RNA-mediated loss-of-function studies show that IAN4 supports positive selection. The knockdown of IAN5 perturbs the optimal generation of CD4/CD8 double-positive thymocytes and reduces the survival of mature T lymphocytes. We also show evidence suggesting that IAN4 and IAN5 are associated with anti-apoptotic proteins Bcl-2 and Bcl-xL, whereas IAN1 is associated with pro-apoptotic Bax. Thus, the IAN family is a novel family of T cell-receptor-responsive proteins that critically regulate thymic development and survival of T lymphocytes and that potentially exert regulatory functions through the association with Bcl-2 family proteins.


Assuntos
Apoptose , Diferenciação Celular , Proteínas de Ligação ao GTP/classificação , Proteínas de Ligação ao GTP/genética , Linfócitos T/citologia , Linfócitos T/metabolismo , Animais , Sobrevivência Celular , Proteínas de Ligação ao GTP/metabolismo , Regulação da Expressão Gênica , Genoma/genética , Humanos , Dados de Sequência Molecular , Filogenia , Ligação Proteica , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Interferência de RNA , Timo/citologia , Timo/metabolismo
19.
J Steroid Biochem Mol Biol ; 97(4): 376-83, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16146692

RESUMO

Liver X receptors (LXRs) play an important role in lipid metabolism. Recently, a role for these proteins was identified in suppressing the inflammatory response. However, it is not known whether the natural ligands of LXRs, e.g. 22(R)-hydroxycholesterol (22R-HC), can suppress the inflammatory response after the onset of inflammation. We demonstrate here that treatment of Lipopolysaccharide (LPS)-activated RAW264.7 macrophages with 22R-HC markedly suppressed nitric oxide (NO) production and inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression. Additionally, 22R-HC did not affect the DNA binding activity of NF-kappaB, AP-1 and C/EBP(s), important transcriptional factors for iNOS and COX-2 genes expression. Furthermore iNOS and COX-2 mRNA suppression by 22R-HC was diminished by cellular treatment with cycloheximide. These results suggest that 22R-HC suppresses the expression of iNOS and COX-2 genes through de novo protein synthesis of an unidentified protein in LPS-activated macrophages.


Assuntos
Ciclo-Oxigenase 2/metabolismo , Inibidores de Ciclo-Oxigenase/farmacologia , Regulação Enzimológica da Expressão Gênica , Hidroxicolesteróis/farmacologia , Macrófagos/metabolismo , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Proteínas/metabolismo , Animais , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Linhagem Celular , Células Cultivadas , DNA/química , Proteínas de Ligação a DNA/metabolismo , Glucocorticoides/metabolismo , Inflamação , Ligantes , Lipopolissacarídeos/química , Lipopolissacarídeos/metabolismo , Receptores X do Fígado , Ativação de Macrófagos , Camundongos , Modelos Estatísticos , NF-kappa B/metabolismo , Óxido Nítrico/metabolismo , Nitritos/metabolismo , Receptores Nucleares Órfãos , Ligação Proteica , RNA/química , RNA/metabolismo , RNA Mensageiro/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Fatores de Tempo , Fator de Transcrição AP-1/metabolismo , Transcrição Gênica
20.
Cancer Immunol Immunother ; 54(8): 729-40, 2005 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-15685448

RESUMO

Expression of an interferon inducible gene 6-16, G1P3, increases not only in type I interferon-treated cells but also in human senescent fibroblasts. However, the function of 6-16 protein is unknown. Here we report that 6-16 is 34 kDa glycosylated protein and localized at mitochondria. Interestingly, 6-16 is expressed at high levels in gastric cancer cell lines and tissues. One of exceptional gastric cancer cell line, TMK-1, which do not express detectable 6-16, is sensitive to apoptosis induced by cycloheximide (CHX), 5-fluorouracil (5-FU) and serum-deprivation. Ectopic expression of 6-16 gene restored the induction of apoptosis and inhibited caspase-3 activity in TMK-1 cells. Thus 6-16 protein has anti-apoptotic function through inhibiting caspas-3. This anti-apoptotic function is expressed through inhibition of the depolarization of mitochondrial membrane potential and release of cytochrome c. By two-hybrid screening, we found that 6-16 protein interacts with calcium and integrin binding protein, CIB/KIP/Calmyrin (CIB), which interacts with presenilin 2, a protein involved in Alzheimer's disease. These protein interactions possibly play a pivotal role in the regulation of apoptosis, for which further detailed analyses are need. These results overall indicate that 6-16 protein may have function as a cell survival protein by inhibiting mitochondrial-mediated apoptosis.


Assuntos
Apoptose , Regulação Neoplásica da Expressão Gênica , Proteínas/genética , Proteínas/fisiologia , Neoplasias Gástricas/genética , Northern Blotting , Sobrevivência Celular , Humanos , Potenciais da Membrana , Mitocôndrias/fisiologia , Proteínas Mitocondriais , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células Tumorais Cultivadas
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