RESUMO
Introduction and objectives: LRBA deficiency is caused by loss of LRBA protein expression, due to either homozygous or compounds heterozygous mutations in LRBA. LRBA deficiency has been shown to affect vesicular trafficking and autophagy. To date, LRBA has been observed in the cytosol, Golgi apparatus and some lysosomes in LPS-stimulated murine macrophages. The objectives of the present study were to study the LRBA localization in organelles involved in vesicular traffic, phagocytosis, and autophagy in mononuclear phagocytes (MP). Materials and methods: We analyzed LRBA colocalization with different endosomes markets using confocal microscopy in MP. We used the autophagy inhibitors to determine the role of LRBA in formation, maturation or degradation of the autophagosome. Results: LRBA intracellular trafficking depends on the activity of the GTPase ADP ribosylation factor-1 (ARF) in MP. LRBA was identified in early, late endosomes but did not colocalize strongly with lysosomal markers. Although LRBA appears not to be recruited during the phagocytic cargo uptake, it greatly colocalized with the microtubule-associated protein 1A/1B-light chain 3 (LC3) under a steady state and this decreased after the induction of autophagy flux. Although the use of inhibitors of lysosome fusion did not restore the LRBA/LC3 colocalization, inhibitors of either early to late endosomes trafficking or PI3K pathway did. Conclusions: Taken together, our results show that LRBA is located in endomembrane system vesicles, mainly in the early and late endosomes. Although LRBA appears not to be involved in the phagocytic uptake, it is recruited in the early steps of the autophagy flux
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Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Membrana Celular/metabolismo , Lipopolissacarídeos/farmacologia , Síndromes de Imunodeficiência/complicações , Diferenciação Celular , Endossomos , Microscopia Confocal/métodos , Autofagossomos , Fatores de Ribosilação do ADP , Fagocitose , Western Blotting , Sistema Fagocitário MononuclearRESUMO
INTRODUCTION AND OBJECTIVES: LRBA deficiency is caused by loss of LRBA protein expression, due to either homozygous or compounds heterozygous mutations in LRBA. LRBA deficiency has been shown to affect vesicular trafficking and autophagy. To date, LRBA has been observed in the cytosol, Golgi apparatus and some lysosomes in LPS-stimulated murine macrophages. The objectives of the present study were to study the LRBA localization in organelles involved in vesicular traffic, phagocytosis, and autophagy in mononuclear phagocytes (MP). MATERIALS AND METHODS: We analyzed LRBA colocalization with different endosomes markets using confocal microscopy in MP. We used the autophagy inhibitors to determine the role of LRBA in formation, maturation or degradation of the autophagosome. RESULTS: LRBA intracellular trafficking depends on the activity of the GTPase ADP ribosylation factor-1 (ARF) in MP. LRBA was identified in early, late endosomes but did not colocalize strongly with lysosomal markers. Although LRBA appears not to be recruited during the phagocytic cargo uptake, it greatly colocalized with the microtubule-associated protein 1A/1B-light chain 3 (LC3) under a steady state and this decreased after the induction of autophagy flux. Although the use of inhibitors of lysosome fusion did not restore the LRBA/LC3 colocalization, inhibitors of either early to late endosomes trafficking or PI3K pathway did. CONCLUSIONS: Taken together, our results show that LRBA is located in endomembrane system vesicles, mainly in the early and late endosomes. Although LRBA appears not to be involved in the phagocytic uptake, it is recruited in the early steps of the autophagy flux.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Endossomos/metabolismo , Membranas Intracelulares/metabolismo , Fatores de Ribosilação do ADP/antagonistas & inibidores , Fatores de Ribosilação do ADP/metabolismo , Autofagia/efeitos dos fármacos , Brefeldina A/farmacologia , Endossomos/efeitos dos fármacos , Humanos , Membranas Intracelulares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Microscopia Confocal , Proteínas Associadas aos Microtúbulos/metabolismo , Fagócitos/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase/farmacologiaRESUMO
Dysregulated immune responses are essential underlying causes of a plethora of pathologies including cancer, autoimmunity, and immunodeficiency. We here investigated 4 patients from unrelated families presenting with immunodeficiency, autoimmunity, and malignancy. We identified 4 distinct homozygous mutations in TNFRSF9 encoding the tumor necrosis factor receptor superfamily member CD137/4-1BB, leading to reduced, or loss of, protein expression. Lymphocytic responses crucial for immune surveillance, including activation, proliferation, and differentiation, were impaired. Genetic reconstitution of CD137 reversed these defects. CD137 deficiency is a novel inborn error of human immunity characterized by lymphocytic defects with early-onset Epstein-Barr virus (EBV)-associated lymphoma. Our findings elucidate a functional role and relevance of CD137 in human immune homeostasis and antitumor responses.
Assuntos
Doenças Autoimunes/genética , Síndromes de Imunodeficiência/genética , Linfoma/genética , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/genética , Doenças Autoimunes/imunologia , Feminino , Predisposição Genética para Doença , Humanos , Síndromes de Imunodeficiência/imunologia , Linfoma/imunologia , Masculino , Linhagem , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/deficiênciaRESUMO
Abstract Background: LPS-responsive beige -like anchor protein (LRBA) deficiency is a primary immunodeficiency disease caused by loss of LRBA protein expression, due to biallelic mutations in LRBA gene. LRBA deficiency patients exhibit a clinically heterogeneous syndrome. The main clinical complication of LRBA deficiency is immune dysregulation. Furthermore, hypogammaglobulinemia is found in more than half of patients with LRBA-deficiency. To date, no patients with this condition have been reported in Colombia Objective: To evaluate the expression of the LRBA protein in patients from Colombia with clinical phenotype associated to LRBA-deficiency. Methods: In the present study the LRBA-expression in patients from Colombia with clinical phenotype associated to LRBA-deficiency was evaluated. After then, the clinical, the immunological characteristics and the possible genetic variants in LRBA or other genes associated with the immune system in patients that exhibit decrease protein expression was evaluated. Results: In total, 112 patients with different clinical manifestations associated to the clinical LRBA phenotype were evaluated. The LRBA expression varies greatly between different healthy donors and patients. Despite the great variability in the LRBA expression, six patients with a decrease in LRBA protein expression were observed. However, no pathogenic or possible pathogenic biallelic variants in LRBA, or in genes related with the immune system were found. Conclusion: LRBA expression varies greatly between different healthy donors and patients. Reduction LRBA-expression in 6 patients without homozygous mutations in LRBA or in associated genes with the immune system was observed. These results suggest the other genetic, epigenetic or environmental mechanisms, that might be regulated the LRBA-expression.
Resumen Antecedentes: la deficiencia de LRBA (del inglés, LPS-responsive beige -like anchor protein) es una inmunodeficiencia primaria causada por la pérdida de la expresión de la proteína LRBA, debido a mutaciones bialélicas en el gen LRBA. Los pacientes con deficiencia de LRBA exhiben un síndrome clínicamente heterogéneo. La principal complicación clínica de la deficiencia de LRBA es la desregulación inmune. Además, la hipogammaglobulinemia se encuentra en más de la mitad de los pacientes con deficiencia de LRBA. Hasta la fecha, no se han reportado pacientes con esta afección en Colombia Objetivo: Evaluar la expresión de la proteína LRBA en pacientes de Colombia con fenotipo clínico asociado a deficiencia de LRBA Métodos: En el presente estudio se evaluó la expresión de LRBA en pacientes de Colombia con fenotipo clínico asociado a deficiencia de LRBA. Después de eso, se evaluaron las características clínicas, inmunológicas y las posibles variantes genéticas en LRBA o en otros genes asociadados con el sistema inmune en pacientes que exhiben una disminución de la expresión de la proteína. Resultados: En total, se evaluaron 112 pacientes con diferentes manifestaciones clínicas asociadas al fenotipo clínico LRBA. La expresión de LRBA varía mucho entre diferentes donantes sanos y pacientes. A pesar de la gran variabilidad en la expresión de LRBA, se observaron seis pacientes con una disminución en la expresión de la proteína LRBA. Sin embargo, no se encontraron variantes bialélicas patógenas o posibles patógenas en LRBA, o en genes relacionados con el sistema inmune. Conclusión: La expresión de LRBA varía mucho entre diferentes donantes sanos y pacientes. Se observó reducción de la expresión de LRBA en 6 pacientes sin mutaciones homocigotas en LRBA o en genes asociados. Estos resultados sugieren los otros mecanismos genéticos, por ejemplo epigenéticos o ambientales, que podrían estar regulados por la expresión de LRBA
Assuntos
Adulto , Criança , Pré-Escolar , Feminino , Humanos , Masculino , Adulto Jovem , Agamaglobulinemia/epidemiologia , Proteínas Adaptadoras de Transdução de Sinal/genética , Síndromes de Imunodeficiência/genética , Fenótipo , Variação Genética , Estudos de Casos e Controles , Regulação da Expressão Gênica , Colômbia , Agamaglobulinemia/genética , Agamaglobulinemia/imunologia , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Síndromes de Imunodeficiência/imunologia , MutaçãoRESUMO
BACKGROUND: LPS-responsive beige -like anchor protein (LRBA) deficiency is a primary immunodeficiency disease caused by loss of LRBA protein expression, due to biallelic mutations in LRBA gene. LRBA deficiency patients exhibit a clinically heterogeneous syndrome. The main clinical complication of LRBA deficiency is immune dysregulation. Furthermore, hypogammaglobulinemia is found in more than half of patients with LRBA-deficiency. To date, no patients with this condition have been reported in Colombia. OBJECTIVE: To evaluate the expression of the LRBA protein in patients from Colombia with clinical phenotype associated to LRBA-deficiency. METHODS: In the present study the LRBA-expression in patients from Colombia with clinical phenotype associated to LRBA-deficiency was evaluated. After then, the clinical, the immunological characteristics and the possible genetic variants in LRBA or other genes associated with the immune system in patients that exhibit decrease protein expression was evaluated. RESULTS: In total, 112 patients with different clinical manifestations associated to the clinical LRBA phenotype were evaluated. The LRBA expression varies greatly between different healthy donors and patients. Despite the great variability in the LRBA expression, six patients with a decrease in LRBA protein expression were observed. However, no pathogenic or possible pathogenic biallelic variants in LRBA, or in genes related with the immune system were found. CONCLUSION: LRBA expression varies greatly between different healthy donors and patients. Reduction LRBA-expression in 6 patients without homozygous mutations in LRBA or in associated genes with the immune system was observed. These results suggest the other genetic, epigenetic or environmental mechanisms, that might be regulated the LRBA-expression.
ANTECEDENTES: la deficiencia de LRBA (del inglés, LPS-responsive beige -like anchor protein) es una inmunodeficiencia primaria causada por la pérdida de la expresión de la proteína LRBA, debido a mutaciones bialélicas en el gen LRBA. Los pacientes con deficiencia de LRBA exhiben un síndrome clínicamente heterogéneo. La principal complicación clínica de la deficiencia de LRBA es la desregulación inmune. Además, la hipogammaglobulinemia se encuentra en más de la mitad de los pacientes con deficiencia de LRBA. Hasta la fecha, no se han reportado pacientes con esta afección en Colombia. OBJETIVO: Evaluar la expresión de la proteína LRBA en pacientes de Colombia con fenotipo clínico asociado a deficiencia de LRBA. MÉTODOS: En el presente estudio se evaluó la expresión de LRBA en pacientes de Colombia con fenotipo clínico asociado a deficiencia de LRBA. Después de eso, se evaluaron las características clínicas, inmunológicas y las posibles variantes genéticas en LRBA o en otros genes asociadados con el sistema inmune en pacientes que exhiben una disminución de la expresión de la proteína. RESULTADOS: En total, se evaluaron 112 pacientes con diferentes manifestaciones clínicas asociadas al fenotipo clínico LRBA. La expresión de LRBA varía mucho entre diferentes donantes sanos y pacientes. A pesar de la gran variabilidad en la expresión de LRBA, se observaron seis pacientes con una disminución en la expresión de la proteína LRBA. Sin embargo, no se encontraron variantes bialélicas patógenas o posibles patógenas en LRBA, o en genes relacionados con el sistema inmune. CONCLUSIÓN: La expresión de LRBA varía mucho entre diferentes donantes sanos y pacientes. Se observó reducción de la expresión de LRBA en 6 pacientes sin mutaciones homocigotas en LRBA o en genes asociados. Estos resultados sugieren los otros mecanismos genéticos, por ejemplo epigenéticos o ambientales, que podrían estar regulados por la expresión de LRBA.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Agamaglobulinemia/epidemiologia , Síndromes de Imunodeficiência/genética , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Adulto , Agamaglobulinemia/genética , Agamaglobulinemia/imunologia , Estudos de Casos e Controles , Criança , Pré-Escolar , Colômbia , Feminino , Regulação da Expressão Gênica , Variação Genética , Humanos , Síndromes de Imunodeficiência/imunologia , Masculino , Mutação , Fenótipo , Adulto JovemRESUMO
Bi-allelic mutations in LRBA (from Lipopolysaccharide-responsive and beige-like anchor protein) result in a primary immunodeficiency with clinical features ranging from hypogammaglobulinemia and lymphoproliferative syndrome to inflammatory bowel disease and heterogeneous autoimmune manifestations. LRBA deficiency has been shown to affect vesicular trafficking, autophagy and apoptosis, which may lead to alterations of several molecules and processes that play key roles for immunity. In this review, we will discuss the relationship of LRBA with the endovesicular system in the context of receptor trafficking, autophagy and apoptosis. Since these mechanisms of homeostasis are inherent to all living cells and not only limited to the immune system and also, because they are involved in physiological as well as pathological processes such as embryogenesis or tumoral transformation, we envisage advancing in the identification of potential pharmacological agents to manipulate these processes.
Las mutaciones bi-alélicas en LRBA (del inglés, Lipopolysaccharide-responsive and beige-like anchor protein) conllevan a una inmunodeficiencia primaria con características clínicas que abarcan desde hipogamaglubulinemia y síndrome linfoproliferativo hasta una enfermedad inflamatoria intestinal y manifestaciones autoinmunes heterogéneas. Se ha demostrado que la deficiencia de LRBA afecta el tráfico vesicular, la autofagia y la apoptosis pudiendo generar alteraciones en la regulación de varios procesos importantes para la inmunidad. En esta revisión discutiremos la relación de LRBA con el sistema endovesicular en el contexto del tráfico de receptores, la autofagia y la apoptosis. Estos mecanismos de homeostasis son inherentes a todas las células y no están limitados a las células del sistema inmune, están involucrados en procesos fisiológicos y patológicos, como la embriogénesis o la transformación tumoral. El entendimiento de la función de LRBA permitirá avanzar en la identificación de los posibles blancos farmacológicos para manipular estos procesos.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Membrana Celular/metabolismo , Síndromes de Imunodeficiência/genética , Agamaglobulinemia/genética , Agamaglobulinemia/imunologia , Animais , Apoptose/fisiologia , Autofagia/fisiologia , Humanos , Síndromes de Imunodeficiência/imunologia , Síndromes de Imunodeficiência/fisiopatologia , Doenças Inflamatórias Intestinais/genética , Doenças Inflamatórias Intestinais/imunologia , Transtornos Linfoproliferativos/genética , Transtornos Linfoproliferativos/imunologia , MutaçãoRESUMO
Abstract Bi-allelic mutations in LRBA (from Lipopolysaccharide-responsive and beige-like anchor protein) result in a primary immunodeficiency with clinical features ranging from hypogammaglobulinemia and lymphoproliferative syndrome to inflammatory bowel disease and heterogeneous autoimmune manifestations. LRBA deficiency has been shown to affect vesicular trafficking, autophagy and apoptosis, which may lead to alterations of several molecules and processes that play key roles for immunity. In this review, we will discuss the relationship of LRBA with the endovesicular system in the context of receptor trafficking, autophagy and apoptosis. Since these mechanisms of homeostasis are inherent to all living cells and not only limited to the immune system and also, because they are involved in physiological as well as pathological processes such as embryogenesis or tumoral transformation, we envisage advancing in the identification of potential pharmacological agents to manipulate these processes.
Resumen Las mutaciones bi-alélicas en LRBA (del inglés, Lipopolysaccharide-responsive and beige-like anchor protein) conllevan a una inmunodeficiencia primaria con características clínicas que abarcan desde hipogamaglubulinemia y síndrome linfoproliferativo hasta una enfermedad inflamatoria intestinal y manifestaciones autoinmunes heterogéneas. Se ha demostrado que la deficiencia de LRBA afecta el tráfico vesicular, la autofagia y la apoptosis pudiendo generar alteraciones en la regulación de varios procesos importantes para la inmunidad. En esta revisión discutiremos la relación de LRBA con el sistema endovesicular en el contexto del tráfico de receptores, la autofagia y la apoptosis. Estos mecanismos de homeostasis son inherentes a todas las células y no están limitados a las células del sistema inmune, están involucrados en procesos fisiológicos y patológicos, como la embriogénesis o la transformación tumoral. El entendimiento de la función de LRBA permitirá avanzar en la identificación de los posibles blancos farmacológicos para manipular estos procesos.
