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1.
Nat Immunol ; 11(12): 1119-26, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21057510

RESUMO

The heterodimeric cytokine interleukin 27 (IL-27) signals through the IL-27Rα subunit of its receptor, combined with gp130, a common receptor chain used by several cytokines, including IL-6. Notably, the IL-27 subunits p28 (IL-27p28) and EBI3 are not always expressed together, which suggests that they may have unique functions. Here we show that IL-27p28, independently of EBI3, antagonized cytokine signaling through gp130 and IL-6-mediated production of IL-17 and IL-10. Similarly, the ability to generate antibody responses was dependent on the activity of gp130-signaling cytokines. Mice transgenic for expression of IL-27p28 showed a substantial defect in the formation of germinal centers and antibody production. Thus, IL-27p28, as a natural antagonist of gp130-mediated signaling, may be useful as a therapeutic for managing inflammation mediated by cytokines that signal through gp130.


Assuntos
Receptor gp130 de Citocina/metabolismo , Interleucinas/metabolismo , Transdução de Sinais/imunologia , Animais , Formação de Anticorpos/imunologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Separação Celular , Receptor gp130 de Citocina/imunologia , Citocinas/imunologia , Citocinas/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Imuno-Histoquímica , Interleucinas/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Antígenos de Histocompatibilidade Menor , Receptores de Citocinas/imunologia , Receptores de Citocinas/metabolismo
2.
Nat Immunol ; 9(12): 1379-87, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18978795

RESUMO

The survival of transitional and mature B cells requires both the B cell antigen receptor (BCR) and BLyS receptor 3 (BR3), which suggests that these receptors send signals that are nonredundant or that engage in crosstalk with each other. Here we show that BCR signaling induced production of the nonclassical transcription factor NF-kappaB pathway substrate p100, which is required for transmission of BR3 signals and thus B cell survival. The capacity for sustained p100 production emerged during transitional B cell differentiation, the stage at which BCR signals begin to mediate survival rather than negative selection. Our findings identify a molecular mechanism for the reliance of primary B cells on continuous BR3 and BCR signaling, as well as for the gradual resistance to negative selection that is acquired during B cell maturation.


Assuntos
Fator Ativador de Células B/metabolismo , Linfócitos B/citologia , Diferenciação Celular/imunologia , NF-kappa B/metabolismo , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais/imunologia , Animais , Fator Ativador de Células B/imunologia , Linfócitos B/imunologia , Linhagem Celular , Sobrevivência Celular/imunologia , Citometria de Fluxo , Humanos , Immunoblotting , Camundongos , NF-kappa B/imunologia , Receptor Cross-Talk/imunologia , Receptores de Antígenos de Linfócitos B/imunologia
3.
Arthritis Rheum ; 65(4): 1043-54, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23334904

RESUMO

OBJECTIVE: To determine the necessity for any individual BAFF receptor in the development of systemic lupus erythematosus (SLE). METHODS: Bcma-, Taci-, and Br3-null mutations were introgressed into NZM 2328 mice. NZM.Bcma-/-, NZM.Taci-/-, and NZM.Br3-/- mice were evaluated for lymphocyte phenotype and BAFF receptor expression by flow cytometry; for B cell responsiveness to BAFF by in vitro culture; for serum levels of BAFF and total IgG and IgG anti-double-stranded DNA (anti-dsDNA) by enzyme-linked immunosorbent assay; for renal immunopathology by immunofluorescence and histopathology; and for clinical disease. RESULTS: BCMA, TACI, and B lymphocyte stimulator receptor 3 (BR3) were not surface-expressed in NZM.Bcma-/-, NZM.Taci-/-, and NZM.Br3-/- mice, respectively. Transitional and follicular B cells from NZM.Br3-/- mice were much less responsive to BAFF than were the corresponding cells from wild-type, NZM.Bcma-/-, or NZM.Taci-/- mice. In comparison with wild-type mice, NZM.Bcma-/- and NZM.Taci-/- mice harbored an increased number of spleen B cells, T cells, and plasma cells, whereas serum levels of total IgG and IgG anti-dsDNA were similar to those in wild-type mice. Despite their paucity of B cells, NZM.Br3-/- mice had an increased number of T cells, and the numbers of plasma cells and levels of IgG anti-dsDNA were similar to those in wild-type mice. Serum levels of BAFF were increased in NZM.Taci-/- and NZM.Br3-/- mice but were decreased in NZM.Bcma-/- mice. Despite their phenotypic differences, NZM.Bcma-/-, NZM.Taci-/-, and NZM.Br3-/- mice had renal immunopathology and clinical disease that were at least as severe as that in wild-type mice. CONCLUSION: Any single BAFF receptor, including BR3, is dispensable for the development of SLE in NZM mice. Development of disease in NZM.Br3-/- mice demonstrates that BAFF-BCMA and/or BAFF-TACI interactions contribute to SLE, and that a profound, life-long reduction in the numbers of B cells does not guarantee protection against SLE.


Assuntos
Antígeno de Maturação de Linfócitos B/metabolismo , Subpopulações de Linfócitos B , Lúpus Eritematoso Sistêmico/metabolismo , Proteína Transmembrana Ativadora e Interagente do CAML/metabolismo , Animais , Anticorpos Antinucleares , Fator Ativador de Células B/farmacologia , Receptor do Fator Ativador de Células B/genética , Receptor do Fator Ativador de Células B/metabolismo , Antígeno de Maturação de Linfócitos B/genética , Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/efeitos dos fármacos , Subpopulações de Linfócitos B/metabolismo , Modelos Animais de Doenças , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Imunoglobulina M/imunologia , Imunoglobulina M/metabolismo , Rim/imunologia , Rim/metabolismo , Rim/patologia , Lúpus Eritematoso Sistêmico/etiologia , Lúpus Eritematoso Sistêmico/imunologia , Camundongos , Camundongos Congênicos , Proteína Transmembrana Ativadora e Interagente do CAML/genética
4.
J Immunol ; 188(11): 5389-96, 2012 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-22529295

RESUMO

The signals required to generate long-lived plasma cells remain unresolved. One widely cited model posits that long-lived plasma cells derive from germinal centers (GCs) in response to T cell-dependent (TD) Ags. Thus, T cell-independent (TI) Ags, which fail to sustain GCs, are considered ineffective at generating long-lived plasma cells. However, we show that long-lived hapten-specific plasma cells are readily induced without formation of GCs. Long-lived plasma cells developed in T cell-deficient mice after a single immunization with haptenated LPS, a widely used TI Ag. Long-lived plasma cells also formed in response to TD Ag when the GC response was experimentally prevented. These observations establish that long-lived plasma cells are induced in both TI and TD responses, and can arise independently of B cell maturation in GCs.


Assuntos
Células da Medula Óssea/imunologia , Diferenciação Celular/imunologia , Epitopos de Linfócito T/imunologia , Plasmócitos/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/metabolismo , Linhagem da Célula/imunologia , Sobrevivência Celular/imunologia , Epitopos de Linfócito T/metabolismo , Feminino , Centro Germinativo/citologia , Centro Germinativo/imunologia , Centro Germinativo/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Plasmócitos/citologia , Plasmócitos/metabolismo , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/metabolismo
5.
J Clin Invest ; 134(7)2024 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-38290087

RESUMO

In response to a meal, insulin drives hepatic glycogen synthesis to help regulate systemic glucose homeostasis. The mechanistic target of rapamycin complex 1 (mTORC1) is a well-established insulin target and contributes to the postprandial control of liver lipid metabolism, autophagy, and protein synthesis. However, its role in hepatic glucose metabolism is less understood. Here, we used metabolomics, isotope tracing, and mouse genetics to define a role for liver mTORC1 signaling in the control of postprandial glycolytic intermediates and glycogen deposition. We show that mTORC1 is required for glycogen synthase activity and glycogenesis. Mechanistically, hepatic mTORC1 activity promotes the feeding-dependent induction of Ppp1r3b, a gene encoding a phosphatase important for glycogen synthase activity whose polymorphisms are linked to human diabetes. Reexpression of Ppp1r3b in livers lacking mTORC1 signaling enhances glycogen synthase activity and restores postprandial glycogen content. mTORC1-dependent transcriptional control of Ppp1r3b is facilitated by FOXO1, a well characterized transcriptional regulator involved in the hepatic response to nutrient intake. Collectively, we identify a role for mTORC1 signaling in the transcriptional regulation of Ppp1r3b and the subsequent induction of postprandial hepatic glycogen synthesis.


Assuntos
Glicogênio Sintase , Glicogênio Hepático , Alvo Mecanístico do Complexo 1 de Rapamicina , Proteína Fosfatase 1 , Animais , Humanos , Camundongos , Glicogênio/genética , Glicogênio/metabolismo , Glicogênio Sintase/metabolismo , Insulina/metabolismo , Fígado/metabolismo , Glicogênio Hepático/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Proteína Fosfatase 1/metabolismo , Período Pós-Prandial
6.
Arthritis Rheum ; 64(5): 1610-9, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22127792

RESUMO

OBJECTIVE: To determine the role of APRIL in the development of systemic lupus erythematosus (SLE) in mice. METHODS: Wild-type (WT) NZM 2328, NZM. April(-/-) , NZM.Baff(-/-) , and NZM.Baff(-/-) .April(-/-) mice were evaluated for lymphocyte phenotype by flow cytometry, for serum total IgG and IgG autoantibody levels by enzyme-linked immunosorbent assay, for glomerular deposition of IgG and C3 by immunofluorescence, for renal changes by histopathology, and for clinical disease by laboratory assessment (severe proteinuria). RESULTS: In comparison to WT mice, NZM.April(-/-) mice harbored increased spleen B cells, T cells, and plasma cells (PCs), increased serum levels of IgG antichromatin antibodies, and decreased numbers of bone marrow (BM) PCs. Glomerular deposition of IgG and C3 was similar in NZM.April(-/-) mice and WT mice, renal changes on histopathology tended to be more severe in NZM.April(-/-) mice than in WT mice, and development of clinical disease was identical in NZM.April(-/-) mice and WT mice. BM (but not spleen) PCs and serum IgG antichromatin and anti-double-stranded DNA antibody levels were lower in NZM.Baff(-/-) .April(-/-) mice than in NZM.Baff(-/-) mice, whereas renal immunopathology in each cohort was equally mild. CONCLUSION: APRIL is dispensable for the development of full-blown SLE in NZM mice. Moreover, the elimination of both APRIL and BAFF had no discernible effect on the development of renal immunopathology or clinical disease beyond that of elimination of BAFF alone. The reduction in BM PCs in hosts doubly deficient in APRIL and BAFF beyond that in hosts deficient only in BAFF raises concern that combined antagonism of APRIL and BAFF may lead to greater immunosuppression without a concomitant increase in therapeutic efficacy.


Assuntos
Fator Ativador de Células B/deficiência , Lúpus Eritematoso Sistêmico/imunologia , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/deficiência , Animais , Autoanticorpos/imunologia , Autoanticorpos/metabolismo , Fator Ativador de Células B/genética , Linfócitos B/imunologia , Linfócitos B/metabolismo , Linfócitos B/patologia , Biomarcadores/metabolismo , Células da Medula Óssea , Complemento C3/imunologia , Complemento C3/metabolismo , Modelos Animais de Doenças , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Terapia de Imunossupressão , Glomérulos Renais/imunologia , Glomérulos Renais/metabolismo , Glomérulos Renais/patologia , Lúpus Eritematoso Sistêmico/metabolismo , Lúpus Eritematoso Sistêmico/patologia , Camundongos , Camundongos Endogâmicos NZB , Camundongos Knockout , Plasmócitos/imunologia , Plasmócitos/metabolismo , Plasmócitos/patologia , Especificidade da Espécie , Baço/imunologia , Baço/metabolismo , Baço/patologia , Linfócitos T/imunologia , Linfócitos T/metabolismo , Linfócitos T/patologia , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/genética
7.
Learn Mem ; 18(4): 191-206, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21422168

RESUMO

Genetic studies in Drosophila have revealed two separable long-term memory pathways defined as anesthesia-resistant memory (ARM) and long-lasting long-term memory (LLTM). ARM is disrupted in radish (rsh) mutants, whereas LLTM requires CREB-dependent protein synthesis. Although the downstream effectors of ARM and LLTM are distinct, pathways leading to these forms of memory may share the cAMP cascade critical for associative learning. Dunce, which encodes a cAMP-specific phosphodiesterase, and rutabaga, which encodes an adenylyl cyclase, both disrupt short-term memory. Amnesiac encodes a pituitary adenylyl cyclase-activating peptide homolog and is required for middle-term memory. Here, we demonstrate that the Radish protein localizes to the cytoplasm and nucleus and is a PKA phosphorylation target in vitro. To characterize how these plasticity pathways may manifest at the synaptic level, we assayed synaptic connectivity and performed an expression analysis to detect altered transcriptional networks in rutabaga, dunce, amnesiac, and radish mutants. All four mutants disrupt specific aspects of synaptic connectivity at larval neuromuscular junctions (NMJs). Genome-wide DNA microarray analysis revealed ∼375 transcripts that are altered in these mutants, suggesting defects in multiple neuronal signaling pathways. In particular, the transcriptional target Lapsyn, which encodes a leucine-rich repeat cell adhesion protein, localizes to synapses and regulates synaptic growth. This analysis provides insights into the Radish-dependent ARM pathway and novel transcriptional targets that may contribute to memory processing in Drosophila.


Assuntos
Proteínas de Drosophila/biossíntese , Drosophila melanogaster/fisiologia , Regulação da Expressão Gênica , Aprendizagem/fisiologia , Memória/fisiologia , Plasticidade Neuronal/fisiologia , Fosfoproteínas/biossíntese , Sinapses/ultraestrutura , Adenilil Ciclases/biossíntese , Adenilil Ciclases/genética , Animais , Western Blotting , Proteínas de Drosophila/genética , Expressão Gênica , Imuno-Histoquímica , Microscopia Eletrônica de Varredura , Mutação , Neuropeptídeos/biossíntese , Neuropeptídeos/genética , Análise de Sequência com Séries de Oligonucleotídeos , Fosfoproteínas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/fisiologia , Sinapses/metabolismo
8.
Hum Gene Ther ; 33(11-12): 614-624, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35229644

RESUMO

Adeno-associated virus (AAV) vector-mediated gene transfer is lessening the impact of monogenetic disorders. Human AAV gene therapy recipients commonly mount immune responses to AAV or the encoded therapeutic protein, which requires transient immunosuppression. Most efforts to date have focused on blunting AAV capsid-specific T cell responses, which have been implicated in elimination of AAV-transduced cells. Here, we explore the use of immunosuppressants, rapamycin given alone or in combination with ibrutinib to inhibit AAV vector- or transgene product-specific antibody responses. Our results show that rapamycin or ibrutinib given alone reduces primary antibody responses against AAV capsid, but the combination of rapamycin and ibrutinib is more effective, blunts recall responses, and reduces numbers of circulating antibody-secreting plasma cells. The drugs fail to lower B cell memory formation or to reduce the inhibitory effects of pre-existing AAV capsid-specific antibodies on transduction efficiency.


Assuntos
Dependovirus , Vetores Genéticos , Adenina/análogos & derivados , Formação de Anticorpos , Proteínas do Capsídeo/genética , Dependovirus/metabolismo , Técnicas de Transferência de Genes , Terapia Genética , Vetores Genéticos/genética , Humanos , Piperidinas , Sirolimo/farmacologia , Sirolimo/uso terapêutico
9.
Front Immunol ; 13: 999021, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36189251

RESUMO

AAV gene transfer is a promising treatment for many patients with life-threatening genetic diseases. However, host immune response to the vector poses a significant challenge for the durability and safety of AAV-mediated gene therapy. Here, we characterize the innate immune response to AAV in human whole blood. We identified neutrophils, monocyte-related dendritic cells, and monocytes as the most prevalent cell subsets able to internalize AAV particles, while conventional dendritic cells were the most activated in terms of the CD86 co-stimulatory molecule upregulation. Although low titers (≤1:10) of AAV neutralizing antibodies (NAb) in blood did not have profound effects on the innate immune response to AAV, higher NAb titers (≥1:100) significantly increased pro-inflammatory cytokine/chemokine secretion, vector uptake by antigen presenting cells (APCs) and complement activation. Interestingly, both full and empty viral particles were equally potent in inducing complement activation and cytokine secretion. By using a compstatin-based C3 and C3b inhibitor, APL-9, we demonstrated that complement pathway inhibition lowered CD86 levels on APCs, AAV uptake, and cytokine/chemokine secretion in response to AAV. Together these results suggest that the pre-existing humoral immunity to AAV may contribute to trigger adverse immune responses observed in AAV-based gene therapy, and that blockade of complement pathway may warrant further investigation as a potential strategy for decreasing immunogenicity of AAV-based therapeutics.


Assuntos
Dependovirus , Vetores Genéticos , Anticorpos Neutralizantes , Citocinas/genética , Dependovirus/genética , Vetores Genéticos/genética , Humanos , Imunidade Humoral
10.
J Exp Med ; 202(9): 1225-34, 2005 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-16260487

RESUMO

Selection of recently formed B cells into the follicular or marginal zone (MZ) compartments is proposed to occur by way of proliferative intermediates expressing high levels of CD21/35 and CD23. However, we show that CD21/35(high) CD23(+) splenocytes are not enriched for proliferative cells, and do not contribute substantially to the generation of follicular B cells. Instead, ontogenic relationships, steady-state labeling kinetics, and adoptive transfer experiments suggest that CD21/35(high) CD23(+) splenocytes serve primarily as precursors for MZ B cells, although their developmental potential seems to be broader and is influenced by environmental cues that are associated with lymphopenia. Furthermore, CD21/35(high) CD23(+) splenocytes share several key functional characteristics with MZ B cells, including their capacity to trap T-independent antigen and a heightened proliferative response to LPS. These observations challenge previous models of peripheral B cell maturation, and suggest that MZ B cells develop by way of CD21/35(high) CD23(+) intermediates.


Assuntos
Linfócitos B/imunologia , Diferenciação Celular/imunologia , Células-Tronco/fisiologia , Animais , Linfócitos B/citologia , Linfócitos B/metabolismo , Bromodesoxiuridina/metabolismo , Proliferação de Células , Células Cultivadas , Cinética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de Complemento/metabolismo , Receptores de Complemento 3b/metabolismo , Receptores de Complemento 3d/metabolismo , Receptores de IgE/metabolismo , Baço/citologia , Baço/imunologia , Baço/metabolismo , Células-Tronco/metabolismo
11.
Proc Natl Acad Sci U S A ; 105(40): 15517-22, 2008 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-18832171

RESUMO

We have used an inhibiting antibody to determine whether preimmune versus antigen-experienced B cells differ in their requisites for BLyS, a cytokine that controls differentiation and survival. Whereas in vivo BLyS inhibition profoundly reduced naïve B cell numbers and primary immune responses, it had a markedly smaller effect on memory B cells and long-lived plasma cells, as well as secondary immune responses. There was heterogeneity within the memory pools, because IgM-bearing memory cells were sensitive to BLyS depletion whereas IgG-bearing memory cells were not, although both were more resistant than naïve cells. There was also heterogeneity within B1 pools, as splenic but not peritoneal B1 cells were diminished by anti-BLyS treatment, yet the number of natural antibody-secreting cells remained constant. Together, these findings show that memory B cells and natural antibody-secreting cells are BLyS-independent and suggest that these pools can be separately manipulated.


Assuntos
Formação de Anticorpos/imunologia , Fator Ativador de Células B/antagonistas & inibidores , Fator Ativador de Células B/fisiologia , Linfócitos B/imunologia , Imunidade Inata/imunologia , Animais , Fator Ativador de Células B/metabolismo , Linfócitos B/citologia , Feminino , Memória Imunológica/imunologia , Camundongos , Camundongos Endogâmicos C57BL
12.
Eval Program Plann ; 86: 101915, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33571720

RESUMO

Youth in military families are frequently challenged by the adjustment demands associated with the deployment and reintegration of a parent. A positive youth development approach was undertaken by the Boys and Girls Clubs of America to develop and implement a Military Teen Ambassadors (MTA) training for youth in military families that would facilitate knowledge of resiliency and reintegration and foster leadership skills to build assets for themselves as well as their peers within their local communities. To determine if MTA was functioning as intended and to refine future programming, this preliminary formative study assessed perceived participant learning outcomes associated with MTA on variables pertaining to knowledge acquisition, perceived skill acquisition, and community needs awareness. Data were collected prior to the training, immediately following the training, and 6 months after the training. Repeated measures analysis indicated significant mean increases over time in knowledge and awareness of resiliency and reintegration; perceived leadership skills; and community awareness. Qualitative findings provided triangulation in the aforementioned areas. These findings strengthen the body of knowledge on resiliency by demonstrating that the 7 Cs model may be an effective strategy to incorporate into leadership development programs seeking to build knowledge of resiliency among military youth. Study limitations, lessons learned, and recommendations for further research are delineated.


Assuntos
Liderança , Militares , Adolescente , Feminino , Humanos , Masculino , Grupo Associado , Avaliação de Programas e Projetos de Saúde
13.
Nat Commun ; 12(1): 6393, 2021 11 04.
Artigo em Inglês | MEDLINE | ID: mdl-34737297

RESUMO

Pompe disease (PD) is a severe neuromuscular disorder caused by deficiency of the lysosomal enzyme acid alpha-glucosidase (GAA). PD is currently treated with enzyme replacement therapy (ERT) with intravenous infusions of recombinant human GAA (rhGAA). Although the introduction of ERT represents a breakthrough in the management of PD, the approach suffers from several shortcomings. Here, we developed a mouse model of PD to compare the efficacy of hepatic gene transfer with adeno-associated virus (AAV) vectors expressing secretable GAA with long-term ERT. Liver expression of GAA results in enhanced pharmacokinetics and uptake of the enzyme in peripheral tissues compared to ERT. Combination of gene transfer with pharmacological chaperones boosts GAA bioavailability, resulting in improved rescue of the PD phenotype. Scale-up of hepatic gene transfer to non-human primates also successfully results in enzyme secretion in blood and uptake in key target tissues, supporting the ongoing clinical translation of the approach.


Assuntos
Doença de Depósito de Glicogênio Tipo II/enzimologia , alfa-Glucosidases/metabolismo , Animais , Autofagia , Terapia de Reposição de Enzimas , Feminino , Doença de Depósito de Glicogênio Tipo II/terapia , Fígado/enzimologia , Masculino , Camundongos , alfa-Glucosidases/genética
14.
Cell Metab ; 33(5): 905-922.e6, 2021 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-33887198

RESUMO

Low-protein diets promote metabolic health in rodents and humans, and the benefits of low-protein diets are recapitulated by specifically reducing dietary levels of the three branched-chain amino acids (BCAAs), leucine, isoleucine, and valine. Here, we demonstrate that each BCAA has distinct metabolic effects. A low isoleucine diet reprograms liver and adipose metabolism, increasing hepatic insulin sensitivity and ketogenesis and increasing energy expenditure, activating the FGF21-UCP1 axis. Reducing valine induces similar but more modest metabolic effects, whereas these effects are absent with low leucine. Reducing isoleucine or valine rapidly restores metabolic health to diet-induced obese mice. Finally, we demonstrate that variation in dietary isoleucine levels helps explain body mass index differences in humans. Our results reveal isoleucine as a key regulator of metabolic health and the adverse metabolic response to dietary BCAAs and suggest reducing dietary isoleucine as a new approach to treating and preventing obesity and diabetes.


Assuntos
Aminoácidos de Cadeia Ramificada/metabolismo , Dieta , Isoleucina/metabolismo , Valina/metabolismo , Tecido Adiposo Branco/metabolismo , Animais , Índice de Massa Corporal , Dieta/veterinária , Metabolismo Energético , Fatores de Crescimento de Fibroblastos/deficiência , Fatores de Crescimento de Fibroblastos/genética , Fatores de Crescimento de Fibroblastos/metabolismo , Humanos , Fígado/metabolismo , Masculino , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/metabolismo , Obesidade/patologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo
15.
J Immunol ; 181(6): 3777-83, 2008 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-18768830

RESUMO

beta-Catenin is a central mediator of Wnt signaling pathway, components of which have been implicated in B cell development and function. B cell progenitors and bone marrow stromal cells express Wnt ligands, Frizzled receptors and Wnt antagonists, suggesting fine tuned regulation of this pathway in B cell development. In particular, deletion of Frizzled 9 gene results in developmental defects at the pre-B stage of development and an accumulation of plasma cells. Furthermore, Wnt signals regulate B cell proliferation through lymphocyte enhancer-binding factor-1. However, it is not known whether Wnt signaling in B cell development is mediated by beta-catenin and whether beta-catenin plays a role in mature B cell function. In this report, we show that mice bearing B cell-specific deletion of beta-catenin have normal B cell development in bone marrow and periphery. A modest defect in plasma cell generation in vitro was documented, which correlated with a defective expression of IRF-4 and Blimp-1. However, B cell response to T-dependent and T-independent Ags in vivo was found to be normal. Thus, beta-catenin expression was found to be dispensable for normal B cell development and function.


Assuntos
Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/imunologia , Diferenciação Celular/imunologia , beta Catenina/fisiologia , Alelos , Animais , Subpopulações de Linfócitos B/metabolismo , Subpopulações de Linfócitos B/patologia , Diferenciação Celular/genética , Linhagem da Célula/genética , Linhagem da Célula/imunologia , Células Cultivadas , Epitopos de Linfócito B/genética , Epitopos de Linfócito B/imunologia , Deleção de Genes , Inativação Gênica/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Proteína Wnt1/deficiência , Proteína Wnt1/genética , beta Catenina/antagonistas & inibidores , beta Catenina/deficiência , beta Catenina/genética
17.
Elife ; 92020 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-33170774

RESUMO

The Pro47Ser variant of p53 (S47) exists in African-descent populations and is associated with increased cancer risk in humans and mice. Due to impaired repression of the cystine importer Slc7a11, S47 cells show increased glutathione (GSH) accumulation compared to cells with wild -type p53. We show that mice containing the S47 variant display increased mTOR activity and oxidative metabolism, as well as larger size, improved metabolic efficiency, and signs of superior fitness. Mechanistically, we show that mTOR and its positive regulator Rheb display increased association in S47 cells; this is due to an altered redox state of GAPDH in S47 cells that inhibits its ability to bind and sequester Rheb. Compounds that decrease glutathione normalize GAPDH-Rheb complexes and mTOR activity in S47 cells. This study reveals a novel layer of regulation of mTOR by p53, and raises the possibility that this variant may have been selected for in early Africa.


Assuntos
Serina-Treonina Quinases TOR/metabolismo , Proteína Supressora de Tumor p53/genética , Substituição de Aminoácidos/genética , Animais , População Negra/genética , Linhagem Celular , Glutationa/metabolismo , Glicólise , Humanos , Mitocôndrias/metabolismo , Oxirredução , Serina-Treonina Quinases TOR/genética , Proteína Supressora de Tumor p53/metabolismo
18.
Cell Rep ; 33(11): 108500, 2020 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-33326785

RESUMO

Immune cell function is influenced by metabolic conditions. Low-glucose, high-lactate environments, such as the placenta, gastrointestinal tract, and the tumor microenvironment, are immunosuppressive, especially for glycolysis-dependent effector T cells. We report that nicotinamide adenine dinucleotide (NAD+), which is reduced to NADH by lactate dehydrogenase in lactate-rich conditions, is a key point of metabolic control in T cells. Reduced NADH is not available for NAD+-dependent enzymatic reactions involving glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and 3-phosphoglycerate dehydrogenase (PGDH). We show that increased lactate leads to a block at GAPDH and PGDH, leading to the depletion of post-GAPDH glycolytic intermediates, as well as the 3-phosphoglycerate derivative serine that is known to be important for T cell proliferation. Supplementing serine rescues the ability of T cells to proliferate in the presence of lactate-induced reductive stress. Directly targeting the redox state may be a useful approach for developing novel immunotherapies in cancer and therapeutic immunosuppression.


Assuntos
Ácido Láctico/metabolismo , NAD/metabolismo , Proliferação de Células , Humanos , Oxirredução
19.
Mol Cell Biol ; 26(16): 6005-15, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16880512

RESUMO

Activation of naïve T cells requires synergistic signals produced by the T-cell receptor (TCR) and by CD28. We previously identified the novel adaptor ALX, which, upon overexpression in Jurkat T cells, inhibited activation of the interleukin-2 (IL-2) promoter by TCR/CD28, suggesting that it is a negative regulator of T-cell activation. To further understand the physiological role of ALX, ALX-deficient mice were generated. Purified T cells from ALX-deficient mice demonstrated increased IL-2 production, CD25 expression, and proliferation in response to TCR/CD28 stimulation. Enhanced IL-2 production and proliferation were also observed when ALX-deficient mice were primed in vivo with ovalbumin-complete Freund's adjuvant and then restimulated ex vivo. Consistent with our initial overexpression studies, these data demonstrate that ALX is a negative regulator of T-cell activation. While TCR/CD28-mediated activations of phosphotyrosine induction, extracellular signal-regulated kinase 1/2, Jun N-terminal protein kinase, IkappaB kinase alpha/beta, and Akt were unaltered, constitutive activation of p38 mitogen-activated protein kinase and its upstream regulators MKK3/6 were observed for ALX-deficient splenocytes. The phenotype of ALX-deficient mice resembled the phenotype of those deficient in the transmembrane adaptor LAX, and an association between ALX and LAX proteins was demonstrated. These results suggest that ALX, in association with LAX, negatively regulates T-cell activation through inhibition of p38.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Regulação para Baixo/genética , Interleucina-2/metabolismo , Ativação Linfocitária/imunologia , Linfócitos T/imunologia , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Envelhecimento , Animais , Formação de Anticorpos/imunologia , Linfócitos B/imunologia , Morte Celular , Proliferação de Células , Interleucina-2/biossíntese , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfoproteínas/metabolismo , Ligação Proteica , Receptores de Interleucina-2/biossíntese , Baço/citologia , Baço/enzimologia , Esplenomegalia , Staphylococcus/imunologia , Superantígenos/imunologia , Linfócitos T/citologia , Linfócitos T/enzimologia
20.
Front Physiol ; 10: 1439, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31849697

RESUMO

Lack of interleukin 15 receptor alpha (IL15RA) increases spontaneous activity, exercise capacity and protects from diet-induced obesity by enhancing muscle energy metabolism, suggesting a role as exercise mimetic for IL15RA antagonists. Using controlled in vivo muscle stimulation mimicking moderate exercise in normal and Il15ra-/- mice, we mapped and contrasted the metabolic pathways activated upon stimulation or deletion of IL15RA. Stimulation caused the differential regulation of 123 out of the 321 detected metabolites (FDR ≤ 0.05 and fold change ≥ ±1.5). The main energy pathways activated were fatty acid oxidation, nucleotide metabolism, and anaplerotic reactions. Notably, resting Il15ra-/- muscles were primed in a semi-exercised state, characterized by higher pool sizes of fatty acids oxidized to support muscle activity. These studies identify the role of IL15RA in the system-wide metabolic response to exercise and should enable translational studies to harness the potential of IL15RA blockade as a novel exercise mimetic strategy.

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