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BMC Dev Biol ; 19(1): 19, 2019 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-31590629


BACKGROUND: Mouse NOTCH1 carries a highly conserved O-fucose glycan at Thr466 in epidermal growth factor-like repeat 12 (EGF12) of the extracellular domain. O-Fucose at this site has been shown by X-ray crystallography to be recognized by both DLL4 and JAG1 Notch ligands. We previously showed that a Notch1 Thr466Ala mutant exhibits very little ligand-induced NOTCH1 signaling in a reporter assay, whereas a Thr466Ser mutation enables the transfer of O-fucose and reverts the NOTCH1 signaling defect. We subsequently generated a mutant mouse with the Thr466Ala mutation termed Notch1[12f](Notch1tm2Pst). Surprisingly, homozygous Notch1[12f/12f] mutants on a mixed background were viable and fertile. RESULTS: We now report that after backcrossing to C57BL/6 J mice for 11-15 generations, few homozygous Notch1[12f/12f] embryos were born. Timed mating showed that embryonic lethality occurred by embryonic day (E) ~E11.5, somewhat delayed compared to mice lacking Notch1 or Pofut1 (the O-fucosyltransferase that adds O-fucose to Notch receptors), which die at ~E9.5. The phenotype of C57BL/6 J Notch1[12f/12f] embryos was milder than mutants affected by loss of a canonical Notch pathway member, but disorganized vasculogenesis in the yolk sac, delayed somitogenesis and development were characteristic. In situ hybridization of Notch target genes Uncx4.1 and Dll3 or western blot analysis of NOTCH1 cleavage did not reveal significant differences at E9.5. However, qRT-PCR of head cDNA showed increased expression of Dll3, Uncx4.1 and Notch1 in E9.5 Notch1[12f/12f] embryos. Sequencing of cDNA from Notch1[12f/12f] embryo heads and Southern analysis showed that the Notch1[12f] locus was intact following backcrossing. We therefore looked for evidence of modifying gene(s) by crossing C57BL/6 J Notch1 [12f/+] mice to 129S2/SvPasCrl mice. Intercrosses of the F1 progeny gave viable F2 Notch1[12f/12f] mice. CONCLUSION: We conclude that the 129S2/SvPasCrl genome contains a dominant modifying gene that rescues the functions of NOTCH1[12f] in signaling. Identification of the modifying gene has the potential to illuminate novel factor(s) that promote Notch signaling when an O-fucose glycan is absent from EGF12 of NOTCH1.

Adv Exp Med Biol ; 1172: 79-96, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31628652


The Interleukin (IL)-10 cytokine family includes IL-10, IL-19, IL-20, IL-22, IL-24, and IL-26, which are considered as Class 2α-helical cytokines. IL-10 is the most important cytokine in suppressing pro-inflammatory responses in all kinds of autoimmune diseases and limiting excessive immune responses. Due to protein structure homology and shared usage of receptor complexes as well as downstream signaling pathway, other IL-10 family cytokines also show indispensable functions in immune regulation, tissue homeostasis, and host defense. In this review, we focus on immune functions and structures of different cytokines in this family and try to better understand how their molecular mechanisms connect to their biological functions. The molecular details regarding their actions also provide useful information in developing candidate immune therapy reagents for a variety of diseases.

Interleucina-10 , Doenças Autoimunes/imunologia , Humanos , Imunoterapia , Interleucina-10/química , Interleucina-10/imunologia , Transdução de Sinais/imunologia , Relação Estrutura-Atividade
J Immunol ; 196(1): 232-43, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26608918


Lunatic, Manic, and Radical Fringe (LFNG, MFNG, and RFNG) are N-acetylglucosaminyltransferases that modify Notch receptors and regulate Notch signaling. Loss of LFNG affects thymic T cell development, and LFNG and MFNG are required for marginal zone (MZ) B cell development. However, roles for MFNG and RFNG in T cell development, RFNG in B cell development, or Fringes in T and B cell activation are not identified. In this study, we show that Lfng/Mfng/Rfng triple knockout (Fng tKO) mice exhibited reduced binding of DLL4 Notch ligand to CD4/CD8 double-negative (DN) T cell progenitors, and reduced expression of NOTCH1 targets Deltex1 and CD25. Fng tKO mice had reduced frequencies of DN1/cKit(+) and DN2 T cell progenitors and CD4(+)CD8(+) double-positive (DP) T cell precursors, but increased frequencies of CD4(+) and CD8(+) single-positive T cells in the thymus. In spleen, Fng tKO mice had reduced frequencies of CD4(+), CD8(+), central memory T cells and MZ B cells, and an increased frequency of effector memory T cells, neutrophils, follicular, and MZ P B cells. The Fng tKO phenotype was cell-autonomous and largely rescued in mice expressing one allele of a single Fng gene. Stimulation of Fng tKO splenocytes with anti-CD3/CD28 beads or LPS gave reduced proliferation compared with controls, and the generation of activated T cells by Concanavalin A or L-PHA was also reduced in Fng tKO mice. Therefore, each Fringe contributes to T and B cell development, and Fringe is required for optimal in vitro stimulation of T and B cells.

Linfócitos B/citologia , Glicosiltransferases/imunologia , Células Precursoras de Linfócitos T/citologia , Proteínas/imunologia , Animais , Linfócitos B/imunologia , Antígenos CD28/imunologia , Complexo CD3/imunologia , Antígenos CD4/metabolismo , Antígenos CD8/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Diferenciação Celular/imunologia , Proliferação de Células , Concanavalina A/farmacologia , Proteínas de Ligação a DNA/imunologia , Glicosiltransferases/genética , Memória Imunológica/imunologia , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Subunidade alfa de Receptor de Interleucina-2/imunologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteína Jagged-2 , Lipopolissacarídeos , Ativação Linfocitária/imunologia , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células Precursoras de Linfócitos T/imunologia , Proteínas/genética , Receptor Notch1/biossíntese , Receptor Notch1/imunologia , Receptor Notch2/biossíntese , Receptor Notch2/imunologia , Proteínas Serrate-Jagged , Timo/citologia
Hepatol Int ; 4(3): 641-8, 2010 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-21063489


PURPOSE: Concanavalin A (Con A)-induced hepatitis is an extensively used animal model of T cell-mediated acute hepatitis. A variety of cytokines, including interleukin 4 (IL-4), interferon gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α), have been shown to play important roles in Con A-induced liver injury. However, the role of IL-2, a critical cytokine in the development and function of T cells and a clinical therapeutics for virus infection and tumor, has not been carefully examined in this model. METHODS: In this study, we investigated the function of IL-2 in Con A-induced hepatitis by using various strategies of rhIL-2 pretreatment. We treated mice with two rhIL-2 administration strategies: a single injection of high dose of rhIL-2 (IL-2(hi), 50 × 10(3) U/mouse) and four injections of low dose of rhIL-2 (IL-2(4lo), 5 × 10(3) U/mouse). RESULTS: IL-2(hi) pretreatment ameliorated Con A-induced liver injury, while IL-2(4lo) aggravated Con A-induced liver injury. IL-2(hi) pretreatment reduced Con A-induced elevation of serum TNF-α while IL-2(4lo) pretreatment did not. Serum IL-4 and TNF-α were high 6 h after Con A injection in IL-2(4lo) mice, while it was undetectable in IL-2(hi) and non-pretreated mice. IL-2(hi) pretreatment reduced Con A-induced accumulation of T cells in liver while IL-2(4lo) pretreatment increased accumulation of NK cells. CONCLUSION: Various strategies of rhIL-2 administration play different roles in Con A-induced hepatitis, suggesting the importance of IL-2 administrative regime in clinical liver diseases.

J Immunol ; 181(10): 7221-9, 2008 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-18981144


Regulatory T cells (Tregs), which are characterized by expression of CD4, CD25, and Foxp3, play a crucial role in the control of immune responses to both self and non-self Ags. To date, there are only limited data on their role in physiological and pathological hepatic immune responses. In this study, we examined the role of hepatic Tregs in immune-mediated liver injury by using the murine Con A-induced hepatitis model. Con A treatment was associated with an increased number of Foxp3(+) Tregs in liver but not in spleen. Moreover, the expression levels of Foxp3, CTLA-4, glucocorticoid-induced TNF receptor, as well as the frequency of CD103 of Tregs were increased after Con A injection, being significantly higher in liver than in spleen. Depleting CD25(+) cells aggravated liver injury, whereas adoptively transferring CD25(+) cells or Tregs reduced liver injury in Con A-treated recipients. Con A treatment induced elevated serum levels and hepatic mononuclear mRNA expressions of TGF-beta, which were reduced by Tregs depletion. In addition, anti-TGF-beta mAbs blocked the suppressive function of Tregs from Con A-treated mice in vitro. Finally, TGF-beta receptor II dominant-negative mice, whose T cells express a dominant negative form of TGFbetaRII and therefore cannot respond to TGF-beta, had a higher mortality rate and severer liver injury than normal mice injected with the same dose of Con A. These results indicate that CD4(+)CD25(+) Tregs play an important role in limiting the liver injury in Con A-induced hepatitis via a TGF-beta-dependent mechanism.

Hepatite/imunologia , Linfócitos T Reguladores/imunologia , Fator de Crescimento Transformador beta/imunologia , Animais , Antígenos CD/biossíntese , Apoptose/imunologia , Antígeno CTLA-4 , Concanavalina A/toxicidade , Citometria de Fluxo , Fatores de Transcrição Forkhead/biossíntese , Hepatite/metabolismo , Marcação In Situ das Extremidades Cortadas , Cadeias alfa de Integrinas/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Mitógenos/toxicidade , Receptores do Fator de Necrose Tumoral/biossíntese , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Crescimento Transformador beta/metabolismo