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1.
J Mol Med (Berl) ; 96(11): 1239-1249, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30293136

RESUMO

In continuously beating cells like cardiac myocytes, there are rapid alterations of cytosolic Ca2+ levels. We therefore hypothesize that decoding Ca2+ signals for hypertrophic signaling requires intracellular Ca2+ microdomains that are partly independent from cytosolic Ca2+. Furthermore, there is a need for a Ca2+ sensor within these microdomains that translates Ca2+ signals into hypertrophic signaling. Recent evidence suggested that the nucleus of cardiac myocytes might be a Ca2+ microdomain and that calcineurin, once translocated into the nucleus, could act as a nuclear Ca2+ sensor. We demonstrate that nuclear calcineurin was able to act as a nuclear Ca2+ sensor detecting local Ca2+ release from the nuclear envelope via IP3R. Nuclear calcineurin mutants defective for Ca2+ binding failed to activate NFAT-dependent transcription. Under hypertrophic conditions Ca2+ transients in the nuclear microdomain were significantly higher than in the cytosol providing a basis for sustained calcineurin/NFAT-mediated signaling uncoupled from cytosolic Ca2+. Measurements of nuclear and cytosolic Ca2+ transients in IP3 sponge mice showed no increase of Ca2+ levels during diastole as we detected in wild-type mice. Nuclei, isolated from ventricular myocytes of mice after chronic Ang II treatment, showed an elevation of IP3R2 expression which was dependent on calcineurin/NFAT signaling and persisted for 3 weeks after removal of the Ang II stimulus. These data provide an explanation how Ca2+ and calcineurin might regulate transcription in cardiomyocytes in response to neurohumoral signals independently from their role in cardiac contraction control. KEY MESSAGES: • Calcineurin acts as an intranuclear Ca2+ sensor to promote NFAT activity. • Nuclear Ca2+ in cardiac myocytes increases via IP3R2 upon Ang II stimulation. • IP3R2 expression is directly dependent on calcineurin/NFAT.

2.
Sci Immunol ; 3(24)2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29907690

RESUMO

Signal transducer and activator of transcription 3 (STAT3) is a central regulator of immune homeostasis. STAT3 levels are strictly controlled, and STAT3 impairment contributes to several diseases including the monogenic autosomal-dominant hyper-immunoglobulin E (IgE) syndrome (AD-HIES). We investigated patients of four consanguineous families with an autosomal-recessive disorder resembling the phenotype of AD-HIES, with symptoms of immunodeficiency, recurrent infections, skeletal abnormalities, and elevated IgE. Patients presented with reduced STAT3 expression and diminished T helper 17 cell numbers, in absence of STAT3 mutations. We identified two distinct homozygous nonsense mutations in ZNF341, which encodes a zinc finger transcription factor. Wild-type ZNF341 bound to and activated the STAT3 promoter, whereas the mutant variants showed impaired transcriptional activation, partly due to nuclear translocation failure. In summary, nonsense mutations in ZNF341 account for the STAT3-like phenotype in four autosomal-recessive kindreds. Thus, ZNF341 is a previously unrecognized regulator of immune homeostasis.

3.
BMC Immunol ; 18(1): 34, 2017 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-28651547

RESUMO

BACKGROUND: The ability of anti-cytokine antibodies to play a disease-causing role in the pathogenesis of immunodeficiencies is widely accepted. The aim of this study was to investigate whether autoantibodies against BAFF (important B cell survival signal), APRIL (important plasma cell survival signal), or Interleukin-21 (important cytokine for immunoglobulin class switch) present an alternative mechanism for the development of the following primary antibody deficiencies (PADs): common variable immune deficiency (CVID) or selective IgA deficiency (sIgAD). RESULTS: Two hundred thirty-two sera from patients with PADs were screened for autoantibodies against cytokines by ELISA. Statistical data analysis yielded a significant difference (p < 0.01) between the healthy donor sera and both PAD cohorts. The analysis was deepened by subdividing the patient collective into groups with distinct B cell phenotypes but no significant differences were found. For selected sera with notable high ELISA-read outs functional analysis ensued. Anti-BAFF and anti-APRIL antibodies were further examined by a B cell survival assay, whilst the functional relevance of putative anti-IL-21 autoantibodies was investigated by means of a STAT3 phosphorylation assay. However, the results of these experiments revealed no discernible functional effect. CONCLUSION: Whilst statistical analysis of ELISA results showed significant differences between patients and healthy controls, in our set of patients functional tests yielded no evidence for an involvement of autoantibodies against BAFF, APRIL, or IL-21 in the pathogenesis of CVID or sIgAD.


Assuntos
Autoanticorpos/fisiologia , Fator Ativador de Células B/imunologia , Síndromes de Imunodeficiência/imunologia , Síndromes de Imunodeficiência/fisiopatologia , Interleucinas/imunologia , Membro 13 da Superfamília de Ligantes de Fatores de Necrose Tumoral/imunologia , Autoanticorpos/sangue , Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/imunologia , Sobrevivência Celular , Imunodeficiência de Variável Comum/imunologia , Imunodeficiência de Variável Comum/fisiopatologia , Humanos , Deficiência de IgA/imunologia , Deficiência de IgA/fisiopatologia , Interleucinas/metabolismo , Fosforilação , Fator de Transcrição STAT3/imunologia
4.
Clin Case Rep ; 4(6): 593-600, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27398204

RESUMO

DOCK8 deficiency is a rare autosomal recessive combined immunodeficiency with high IgE level, eosinophilia, severe eczema, extensive cutaneous viral, and respiratory bacterial infections, mostly in populations with higher prevalence of consanguinity. Molecular diagnosis of this gene is a useful approach for early diagnosis and timely HSCT due to deleterious consequences.

5.
J Clin Immunol ; 36(1): 73-84, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26604104

RESUMO

PURPOSE: Gain-of-function (GOF) mutations in the signal transducer and activator of transcription 1 (STAT1) result in unbalanced STAT signaling and cause immune dysregulation and immunodeficiency. The latter is often characterized by the susceptibility to recurrent Candida infections, resulting in the clinical picture of chronic mucocutaneous candidiasis (CMC). This study aims to assess the frequency of GOF STAT1 mutations in a large international cohort of CMC patients. METHODS: STAT1 was sequenced in genomic DNA from 57 CMC patients and 35 healthy family members. The functional relevance of nine different STAT1 variants was shown by flow cytometric analysis of STAT1 phosphorylation in patients' peripheral blood cells (PBMC) after stimulation with interferon (IFN)-α, IFN-γ or interleukin-27 respectively. Extended clinical data sets were collected and summarized for 26 patients. RESULTS: Heterozygous mutations within STAT1 were identified in 35 of 57 CMC patients (61%). Out of 39 familial cases from 11 families, 26 patients (67%) from 9 families and out of 18 sporadic cases, 9 patients (50%) were shown to have heterozygous mutations within STAT1. Thirteen distinct STAT1 mutations are reported in this paper. Eight of these mutations are known to cause CMC (p.M202V, p.A267V, p.R274W, p.R274Q, p.T385M, p.K388E, p.N397D, and p.F404Y). However, five STAT1 variants (p.F172L, p.Y287D, p.P293S, p.T385K and p.S466R) have not been reported before in CMC patients. CONCLUSION: STAT1 mutations are frequently observed in patients suffering from CMC. Thus, sequence analysis of STAT1 in CMC patients is advised. Measurement of IFN- or IL-induced STAT1 phosphorylation in PBMC provides a fast and reliable diagnostic tool and should be carried out in addition to genetic testing.


Assuntos
Candidíase Mucocutânea Crônica/diagnóstico , Síndromes de Imunodeficiência/diagnóstico , Leucócitos Mononucleares/imunologia , Mutação/genética , Fator de Transcrição STAT1/metabolismo , Adulto , Candidíase Mucocutânea Crônica/genética , Células Cultivadas , Citocinas/metabolismo , Análise Mutacional de DNA , Feminino , Humanos , Síndromes de Imunodeficiência/genética , Masculino , Linhagem , Fenótipo , Estrutura Terciária de Proteína/genética , Fator de Transcrição STAT1/genética
6.
J Allergy Clin Immunol ; 136(2): 402-12, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25724123

RESUMO

BACKGROUND: Mutations in dedicator of cytokinesis 8 (DOCK8) cause a combined immunodeficiency (CID) also classified as autosomal recessive (AR) hyper-IgE syndrome (HIES). Recognizing patients with CID/HIES is of clinical importance because of the difference in prognosis and management. OBJECTIVES: We sought to define the clinical features that distinguish DOCK8 deficiency from other forms of HIES and CIDs, study the mutational spectrum of DOCK8 deficiency, and report on the frequency of specific clinical findings. METHODS: Eighty-two patients from 60 families with CID and the phenotype of AR-HIES with (64 patients) and without (18 patients) DOCK8 mutations were studied. Support vector machines were used to compare clinical data from 35 patients with DOCK8 deficiency with those from 10 patients with AR-HIES without a DOCK8 mutation and 64 patients with signal transducer and activator of transcription 3 (STAT3) mutations. RESULTS: DOCK8-deficient patients had median IgE levels of 5201 IU, high eosinophil levels of usually at least 800/µL (92% of patients), and low IgM levels (62%). About 20% of patients were lymphopenic, mainly because of low CD4(+) and CD8(+) T-cell counts. Fewer than half of the patients tested produced normal specific antibody responses to recall antigens. Bacterial (84%), viral (78%), and fungal (70%) infections were frequently observed. Skin abscesses (60%) and allergies (73%) were common clinical problems. In contrast to STAT3 deficiency, there were few pneumatoceles, bone fractures, and teething problems. Mortality was high (34%). A combination of 5 clinical features was helpful in distinguishing patients with DOCK8 mutations from those with STAT3 mutations. CONCLUSIONS: DOCK8 deficiency is likely in patients with severe viral infections, allergies, and/or low IgM levels who have a diagnosis of HIES plus hypereosinophilia and upper respiratory tract infections in the absence of parenchymal lung abnormalities, retained primary teeth, and minimal trauma fractures.


Assuntos
Infecções Bacterianas/complicações , Fatores de Troca do Nucleotídeo Guanina/deficiência , Síndrome de Job/complicações , Fenótipo , Dermatopatias/complicações , Viroses/complicações , Adolescente , Adulto , Antígenos de Bactérias/sangue , Antígenos de Bactérias/imunologia , Antígenos Virais/sangue , Antígenos Virais/imunologia , Infecções Bacterianas/genética , Infecções Bacterianas/imunologia , Infecções Bacterianas/mortalidade , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/patologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/patologia , Criança , Pré-Escolar , Eosinófilos/imunologia , Eosinófilos/patologia , Feminino , Fatores de Troca do Nucleotídeo Guanina/genética , Fatores de Troca do Nucleotídeo Guanina/imunologia , Humanos , Imunoglobulina E/sangue , Imunoglobulina E/genética , Imunoglobulina M/sangue , Imunoglobulina M/genética , Lactente , Síndrome de Job/genética , Síndrome de Job/imunologia , Síndrome de Job/mortalidade , Contagem de Linfócitos , Masculino , Pessoa de Meia-Idade , Mutação , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/imunologia , Dermatopatias/genética , Dermatopatias/imunologia , Dermatopatias/mortalidade , Máquina de Vetores de Suporte , Análise de Sobrevida , Viroses/genética , Viroses/imunologia , Viroses/mortalidade
7.
Iran J Allergy Asthma Immunol ; 14(2): 126-32, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25780878

RESUMO

Hyperimmunoglobulin E Syndrome (HIES) is a complex primary immunodeficiency characterized by both immunologic and non-immunologic manifestations. High serum IgE level, eosinophilia, eczema, recurrent skin and lung infections constitute the immunologic profile of HIES, whereas characteristic facial appearance, scoliosis, retained primary teeth, joint hyperextensibility, bone fractures following minimal trauma and craniosynostosis are the main non-immunologic manifestations. The diagnosis of HIES cannot be made by routine immunologic tests. As the main characteristic laboratory abnormalities of this syndrome are highly elevated serum IgE levels and eosinophilia; both features have a broad spectrum of differential diagnosis. The purpose of this essay was presenting the best way for diagnosis management of HIES. Based on the genetic reports of patients of the Center for Chronic Immunodeficiency (CCI) as a single center experience, and applying project management (PM) in health care research projects, we sought the best way for a rapid diagnosis of HIES. The combination of project management principles with immunologic and genetic knowledge to better define the laboratory and clinical diagnosis lead to an improvement of the management of patients with HIES. These results are shown in one "Decision Tree" which is based on 342 genetic reports of the CCI during the past ten years. It is necessary to facilitate the diagnostic analysis of suspected HIES patients; applying project management in health care research projects provides a better and more accurate diagnosis eventually leading to a better patients' care. This Abstract was presented at 16th Biennial Meeting of the European Society for Immunodeficiencies (ESID 2014), Prague, Czech Republic.


Assuntos
Árvores de Decisões , Síndrome de Job/diagnóstico , Humanos
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