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1.
Nat Commun ; 12(1): 5329, 2021 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-34504078

RESUMO

Heterodimeric capping protein (CP/CapZ) is an essential factor for the assembly of branched actin networks, which push against cellular membranes to drive a large variety of cellular processes. Aside from terminating filament growth, CP potentiates the nucleation of actin filaments by the Arp2/3 complex in branched actin networks through an unclear mechanism. Here, we combine structural biology with in vitro reconstitution to demonstrate that CP not only terminates filament elongation, but indirectly stimulates the activity of Arp2/3 activating nucleation promoting factors (NPFs) by preventing their association to filament barbed ends. Key to this function is one of CP's C-terminal "tentacle" extensions, which sterically masks the main interaction site of the terminal actin protomer. Deletion of the ß tentacle only modestly impairs capping. However, in the context of a growing branched actin network, its removal potently inhibits nucleation promoting factors by tethering them to capped filament ends. End tethering of NPFs prevents their loading with actin monomers required for activation of the Arp2/3 complex and thus strongly inhibits branched network assembly both in cells and reconstituted motility assays. Our results mechanistically explain how CP couples two opposed processes-capping and nucleation-in branched actin network assembly.


Assuntos
Proteínas de Capeamento de Actina/metabolismo , Citoesqueleto de Actina/metabolismo , Complexo 2-3 de Proteínas Relacionadas à Actina/metabolismo , Actinas/metabolismo , Citoesqueleto/metabolismo , Melanócitos/metabolismo , Proteínas de Capeamento de Actina/química , Proteínas de Capeamento de Actina/genética , Citoesqueleto de Actina/ultraestrutura , Complexo 2-3 de Proteínas Relacionadas à Actina/química , Complexo 2-3 de Proteínas Relacionadas à Actina/genética , Actinas/química , Actinas/genética , Animais , Sítios de Ligação , Bovinos , Citoesqueleto/ultraestrutura , Gelsolina/química , Gelsolina/genética , Gelsolina/metabolismo , Regulação da Expressão Gênica , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/química , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Cinética , Melanócitos/citologia , Melanoma Experimental/genética , Melanoma Experimental/metabolismo , Melanoma Experimental/patologia , Camundongos , Modelos Moleculares , Profilinas/química , Profilinas/genética , Profilinas/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Timo/citologia , Timo/metabolismo , Proteína Neuronal da Síndrome de Wiskott-Aldrich/química , Proteína Neuronal da Síndrome de Wiskott-Aldrich/genética , Proteína Neuronal da Síndrome de Wiskott-Aldrich/metabolismo
2.
Front Immunol ; 12: 669943, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34211466

RESUMO

Major Histocompatibility Complex (MHC) class II (MHCII) deficiency (MHCII-D), also known as Bare Lymphocyte Syndrome (BLS), is a rare combined immunodeficiency due to mutations in genes regulating expression of MHCII molecules. MHCII deficiency results in impaired cellular and humoral immune responses, leading to severe infections and autoimmunity. Abnormal cross-talk with developing T cells due to the absence of MHCII expression likely leads to defects in thymic epithelial cells (TEC). However, the contribution of TEC alterations to the pathogenesis of this primary immunodeficiency has not been well characterized to date, in particular in regard to immune dysregulation. To this aim, we have performed an in-depth cellular and molecular characterization of TEC in this disease. We observed an overall perturbation of thymic structure and function in both MHCII-/- mice and patients. Transcriptomic and proteomic profiling of murine TEC revealed several alterations. In particular, we demonstrated that impairment of lymphostromal cross-talk in the thymus of MHCII-/- mice affects mTEC maturation and promiscuous gene expression and causes defects of central tolerance. Furthermore, we observed peripheral tolerance impairment, likely due to defective Treg cell generation and/or function and B cell tolerance breakdown. Overall, our findings reveal disease-specific TEC defects resulting in perturbation of central tolerance and limiting the potential benefits of hematopoietic stem cell transplantation in MHCII deficiency.


Assuntos
Células Epiteliais/imunologia , Antígenos de Histocompatibilidade Classe II/imunologia , Tolerância Imunológica , Imunodeficiência Combinada Severa/imunologia , Timo/imunologia , Adolescente , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Estudos de Casos e Controles , Criança , Pré-Escolar , Modelos Animais de Doenças , Células Epiteliais/metabolismo , Europa (Continente) , Feminino , Transplante de Células-Tronco Hematopoéticas , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/metabolismo , Proteínas de Homeodomínio/genética , Humanos , Lactente , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , América do Norte , Proteoma , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/metabolismo , Imunodeficiência Combinada Severa/cirurgia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Timócitos , Timo/metabolismo , Transcriptoma , Adulto Jovem
3.
Front Immunol ; 12: 669893, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34140950

RESUMO

Down syndrome (DS) patients prematurely show clinical manifestations usually associated with aging. Their immune system declines earlier than healthy individuals, leading to increased susceptibility to infections and higher incidence of autoimmune phenomena. Clinical features of accelerated aging indicate that trisomy 21 increases the biological age of tissues. Based on previous studies suggesting immune senescence in DS, we hypothesized that induction of cellular senescence may contribute to early thymic involution and immune dysregulation. Immunohistochemical analysis of thymic tissue showed signs of accelerated thymic aging in DS patients, normally seen in older healthy subjects. Moreover, our whole transcriptomic analysis on human Epcam-enriched thymic epithelial cells (hTEC), isolated from three DS children, which revealed disease-specific transcriptomic alterations. Gene set enrichment analysis (GSEA) of DS TEC revealed an enrichment in genes involved in cellular response to stress, epigenetic histone DNA modifications and senescence. Analysis of senescent markers and oxidative stress in hTEC and thymocytes confirmed these findings. We detected senescence features in DS TEC, thymocytes and peripheral T cells, such as increased ß-galactosidase activity, increased levels of the cell cycle inhibitor p16, telomere length and integrity markers and increased levels of reactive oxygen species (ROS), all factors contributing to cellular damage. In conclusion, our findings support the key role of cellular senescence in the pathogenesis of immune defect in DS while adding new players, such as epigenetic regulation and increased oxidative stress, to the pathogenesis of immune dysregulation.


Assuntos
Proliferação de Células , Senescência Celular , Síndrome de Down/metabolismo , Células Epiteliais/metabolismo , Imunossenescência , Estresse Oxidativo , Timócitos/metabolismo , Timo/metabolismo , Fatores Etários , Estudos de Casos e Controles , Proliferação de Células/genética , Senescência Celular/genética , Criança , Pré-Escolar , Síndrome de Down/genética , Síndrome de Down/imunologia , Síndrome de Down/patologia , Epigênese Genética , Células Epiteliais/imunologia , Células Epiteliais/patologia , Feminino , Perfilação da Expressão Gênica , Humanos , Imunossenescência/genética , Lactente , Masculino , Estresse Oxidativo/genética , Timócitos/imunologia , Timócitos/patologia , Timo/imunologia , Timo/patologia , Transcriptoma
4.
Res Vet Sci ; 138: 90-99, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34126450

RESUMO

With the rapid development of the poultry breeding industry and highly intensive production management, the losses caused by stress responses are becoming increasingly serious. To screen candidate genes related to chicken stress and provide a basis for future research on the molecular mechanisms governing the effects of stress on chicken immune function, we successfully constructed a chicken stress model by exogenously introducing corticosterone (CORT). RNA-seq technology was used to identify and analyze the mRNA and enrichment pathways of the thymus in the stress model group and the control group. The results showed that there were 101 significantly differentially expressed genes (SDEGs) (Padj < 0.05, |log2fold changes| ≥ 1 and FPKM >1), of which 44 were upregulated genes, while 57 were downregulated genes. Gene Ontology (GO) enrichment analysis found that the terms related to immunity or stress mainly included antigen processing and presentation, positive regulation of T cell-mediated immunity, and immune effector process. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the main pathways related to immunity or stress were the PPAR signaling pathway, NOD-like receptor signaling pathway, and intestinal immune network for IgA production. Among the SDEGs, XCL1, HSPA8, DMB1 and BAG3 are strongly related to immunity or stress and may be important genes involved in regulating stress affecting the immune function of chickens. The above results provide a theoretical reference for subsequent research on the molecular regulatory mechanisms by which stress affects the immune function of poultry.


Assuntos
Galinhas/genética , Imunidade/genética , Timo/imunologia , Transcriptoma , Animais , Galinhas/imunologia , Distribuição Aleatória , Estresse Fisiológico/imunologia , Timo/metabolismo
5.
Sci Rep ; 11(1): 10270, 2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-33986327

RESUMO

Newcastle disease (ND), caused by virulent Newcastle disease virus (NDV), is a contagious viral disease affecting various birds and poultry worldwide. In this project, differentially expressed (DE) circRNAs, miRNAs and mRNAs were identified by high-throughput RNA sequencing (RNA-Seq) in chicken thymus at 24, 48, 72 or 96 h post LaSota NDV vaccine injection versus pre-inoculation group. The vital terms or pathways enriched by vaccine-influenced genes were tested through KEGG and GO analysis. DE genes implicated in innate immunity were preliminarily screened out through GO, InnateDB and Reactome Pathway databases. The interaction networks of DE innate immune genes were established by STRING website. Considering the high expression of gga-miR-6631-5p across all the four time points, DE circRNAs or mRNAs with the possibility to bind to gga-miR-6631-5p were screened out. Among DE genes that had the probability to interact with gga-miR-6631-5p, 7 genes were found to be related to innate immunity. Furthermore, gga-miR-6631-5p promoted LaSota NDV replication by targeting insulin induced gene 1 (INSIG1) in DF-1 chicken fibroblast cells. Taken together, our data provided the comprehensive information about molecular responses to NDV LaSota vaccine in Chinese Partridge Shank Chickens and elucidated the vital roles of gga-miR-6631-5p/INSIG1 axis in LaSota NDV replication.


Assuntos
Doença de Newcastle/genética , Pequeno RNA não Traduzido/genética , Replicação Viral/genética , Animais , Galinhas/genética , Galinhas/virologia , Expressão Gênica/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/genética , Imunidade Inata , MicroRNAs/genética , Doença de Newcastle/virologia , Vírus da Doença de Newcastle/genética , Vírus da Doença de Newcastle/patogenicidade , Doenças das Aves Domésticas/virologia , RNA Circular/genética , RNA Mensageiro/genética , Timo/metabolismo , Timo/virologia , Transcriptoma/genética , Vacinação
6.
BMC Vet Res ; 17(1): 182, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33933084

RESUMO

BACKGROUND: Mechanisms of fetal death following maternal PRRSV2 infection remain uncharacterized, although hypoxia from umbilical cord lesions and/or placental detachment due to apoptosis are hypothesized. We performed two experiments examining hypoxia and apoptosis in PRRSV-infected and non-infected, third-trimester fetuses to elucidate possible associations with fetal death. Fetuses were selected based on four phenotypic infection groups: fetuses from non-challenged control gilts (CTRL); low viral load fetuses (LVL; Exp 1) or uninfected fetuses (UNINF; Exp 2) from inoculated gilts; viable high viral load fetuses (HVL-VIA); and HVL meconium-stained fetuses (HVL-MEC). RESULTS: In experiment 1, paraffin embedded fetal tissues collected 21 days post maternal infection (DPI) were examined for DNA fragmentation associated with apoptosis. Positively stained foci were larger and more numerous (P < 0.05) in heart, liver, and thymus of HVL-VIA and HVL-MEC compared to CTRL and LVL fetuses. In experiment 2, group differences in gene expression within the hypoxia (HIF1a, IDO1, VEGFa, LDHA, NOS2, NOX1) and apoptosis (CASP3, CASP7, CASP8, CASP9, RIPK1, RIPK3) pathways were assessed by RT-qPCR in fetal tissues collected at 12 DPI. High viral load fetuses showed differential expression relative to the CTRL and UNINF (P < 0.05 for all). Brain tissue from HVL-VIA and HVL-MEC fetuses presented increased expression of CASP7, CASP8, RIPK3, HIF1a and IDO1. Fetal heart showed increased expression of CASP8, HIF1a, IDO and NOX1 and a decrease in NOS2 expression in infected groups. CASP7, CASP9, RIPK1 and RIPK3 were only increased in the heart of HVL-VIA while VEGFa was only increased for HVL-MEC fetuses. Thymus from HVL-MEC had decreased expression of CASP9 and there was increased IDO1 in all infected fetuses. CONCLUSIONS: There is strong evidence of apoptosis occurring in the heart, liver and thymus of highly viral load fetuses at 21 DPI. Furthermore, there was clear upregulation of apoptotic genes in the heart of high viral load infected fetuses and less prominent upregulation in the brain of PRRSV-infected fetuses, whereas thymus appears to be spared at 12 DPI. There was no strong evidence of hypoxia at 12 DPI in brain and thymus but some indication of hypoxia occurring in fetal heart.


Assuntos
Apoptose , Hipóxia Fetal/veterinária , Síndrome Respiratória e Reprodutiva Suína/patologia , Complicações Infecciosas na Gravidez/veterinária , Animais , Encéfalo/metabolismo , Feminino , Feto/virologia , Expressão Gênica , Miocárdio/metabolismo , Síndrome Respiratória e Reprodutiva Suína/virologia , Vírus da Síndrome Respiratória e Reprodutiva Suína , Gravidez , Complicações Infecciosas na Gravidez/virologia , Sus scrofa , Suínos , Timo/metabolismo , Carga Viral/veterinária
7.
Eur J Immunol ; 51(8): 2006-2026, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33960413

RESUMO

The NF-κB transcription factor c-Rel is a critical regulator of Treg ontogeny, controlling multiple points of the stepwise developmental pathway. Here, we found that the thymic Treg defect in c-Rel-deficient (cRel-/- ) mice is quantitative, not qualitative, based on analyses of TCR repertoire and TCR signaling strength. However, these parameters are altered in the thymic Treg-precursor population, which is also markedly diminished in cRel-/- mice. Moreover, c-Rel governs the transcriptional programme of both thymic and peripheral Tregs, controlling a core of genes involved with immune signaling, and separately in the periphery, cell cycle progression. Last, the immune suppressive function of peripheral cRel-/- tTregs is diminished in a lymphopenic model of T cell proliferation and is associated with decreased stability of Foxp3 expression. Collectively, we show that c-Rel is a transcriptional regulator that controls multiple aspects of Treg development, differentiation, and function via distinct mechanisms.


Assuntos
Proteínas Proto-Oncogênicas c-rel/imunologia , Proteínas Proto-Oncogênicas c-rel/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Animais , Diferenciação Celular/imunologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Timo/imunologia , Timo/metabolismo
8.
Nature ; 594(7863): 413-417, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33981034

RESUMO

Humans and their microbiota have coevolved a mutually beneficial relationship in which the human host provides a hospitable environment for the microorganisms and the microbiota provides many advantages for the host, including nutritional benefits and protection from pathogen infection1. Maintaining this relationship requires a careful immune balance to contain commensal microorganisms within the lumen while limiting inflammatory anti-commensal responses1,2. Antigen-specific recognition of intestinal microorganisms by T cells has previously been described3,4. Although the local environment shapes the differentiation of effector cells3-5 it is unclear how microbiota-specific T cells are educated in the thymus. Here we show that intestinal colonization in early life leads to the trafficking of microbial antigens from the intestine to the thymus by intestinal dendritic cells, which then induce the expansion of microbiota-specific T cells. Once in the periphery, microbiota-specific T cells have pathogenic potential or can protect against related pathogens. In this way, the developing microbiota shapes and expands the thymic and peripheral T cell repertoire, allowing for enhanced recognition of intestinal microorganisms and pathogens.


Assuntos
Células Dendríticas/imunologia , Microbioma Gastrointestinal/imunologia , Linfócitos T/citologia , Linfócitos T/imunologia , Timo/citologia , Timo/imunologia , Envelhecimento/imunologia , Animais , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/metabolismo , Receptor 1 de Quimiocina CX3C/metabolismo , DNA Bacteriano/análise , Células Dendríticas/metabolismo , Escherichia coli/imunologia , Feminino , Masculino , Camundongos , Especificidade de Órgãos , Salmonella/imunologia , Simbiose/imunologia , Timo/metabolismo
9.
Front Immunol ; 12: 658601, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33995376

RESUMO

Antigen presentation by MHC-II proteins in the thymus is central to selection of CD4 T cells, but analysis of the full repertoire of presented peptides responsible for positive and negative selection is complicated by the low abundance of antigen presenting cells. A key challenge in analysis of limiting abundance immunopeptidomes by mass spectrometry is distinguishing true MHC-binding peptides from co-eluting non-specifically bound peptides present in the mixture eluted from immunoaffinity-purified MHC molecules. Herein we tested several approaches to minimize the impact of non-specific background peptides, including analyzing eluates from isotype-control antibody-conjugated beads, considering only peptides present in nested sets, and using predicted binding motif analysis to identify core epitopes. We evaluated these methods using well-understood human cell line samples, and then applied them to analysis of the I-Ab presented immunopeptidome of the thymus of C57BL/6 mice, comparing this to the more easily characterized splenic B cell and dendritic cell populations. We identified a total of 3473 unique peptides eluted from the various tissues, using a data dependent acquisition strategy with a false-discovery rate of <1%. The immunopeptidomes presented in thymus as compared to splenic B cells and DCs identified shared and tissue-specific epitopes. A broader length distribution was observed for peptides presented in the thymus as compared to splenic B cells or DCs. Detailed analysis of 61 differentially presented peptides indicated a wider distribution of I-Ab binding affinities in thymus as compared to splenic B cells. These results suggest different constraints on antigen processing and presentation pathways in central versus peripheral tissues.


Assuntos
Apresentação do Antígeno/imunologia , Mapeamento de Epitopos , Epitopos/imunologia , Peptídeos/imunologia , Timo/imunologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Linfócitos B/imunologia , Linfócitos B/metabolismo , Linhagem Celular , Biologia Computacional/métodos , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Mapeamento de Epitopos/métodos , Epitopos/química , Antígenos HLA-DR/química , Antígenos HLA-DR/imunologia , Antígenos de Histocompatibilidade Classe II/química , Antígenos de Histocompatibilidade Classe II/imunologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Peptídeos/química , Ligação Proteica , Baço/imunologia , Baço/metabolismo , Timo/metabolismo
10.
Nucleic Acids Res ; 49(10): 5760-5778, 2021 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-34037780

RESUMO

Alternative pre-mRNA splicing is a critical step to generate multiple transcripts, thereby dramatically enlarging the proteomic diversity. Thus, a common feature of most alternative splicing factor knockout models is lethality. However, little is known about lineage-specific alternative splicing regulators in a physiological setting. Here, we report that NSrp70 is selectively expressed in developing thymocytes, highest at the double-positive (DP) stage. Global splicing and transcriptional profiling revealed that NSrp70 regulates the cell cycle and survival of thymocytes by controlling the alternative processing of various RNA splicing factors, including the oncogenic splicing factor SRSF1. A conditional-knockout of Nsrp1 (NSrp70-cKO) using CD4Cre developed severe defects in T cell maturation to single-positive thymocytes, due to insufficient T cell receptor (TCR) signaling and uncontrolled cell growth and death. Mice displayed severe peripheral lymphopenia and could not optimally control tumor growth. This study establishes a model to address the function of lymphoid-lineage-specific alternative splicing factor NSrp70 in a thymic T cell developmental pathway.


Assuntos
Processamento Alternativo/genética , Carcinogênese/metabolismo , Desenvolvimento Embrionário/genética , Hematopoese/genética , Melanoma/metabolismo , Timócitos/metabolismo , Animais , Antígenos CD/metabolismo , Antígenos de Diferenciação de Linfócitos T/metabolismo , Apoptose/genética , Carcinogênese/genética , Proliferação de Células/genética , Genômica , Células HEK293 , Humanos , Lectinas Tipo C/metabolismo , Linfopenia/genética , Linfopenia/metabolismo , Melanoma/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Reação em Cadeia da Polimerase , RNA-Seq , Reação em Cadeia da Polimerase em Tempo Real , Receptores de Antígenos de Linfócitos T/metabolismo , Fatores de Processamento de Serina-Arginina/genética , Fatores de Processamento de Serina-Arginina/metabolismo , Timo/embriologia , Timo/metabolismo
11.
Front Immunol ; 12: 642173, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33815395

RESUMO

The suppressor of cytokine signaling 3 (SOCS3) is a major regulator of immune responses and inflammation as it negatively regulates cytokine signaling. Here, the role of SOCS3 in thymic T cell formation was studied in Socs3 fl/fl Actin-creER mice (Δsocs3) with a tamoxifen inducible and ubiquitous Socs3 deficiency. Δsocs3 thymi showed a 90% loss of cellularity and altered cortico-medullary organization. Thymocyte differentiation and proliferation was impaired at the early double negative (CD4-CD8-) cell stage and apoptosis was increased during the double positive (CD4+CD8+) cell stage, resulting in the reduction of recent thymic emigrants in peripheral organs. Using bone marrow chimeras, transplanting thymic organoids and using mice deficient of SOCS3 in thymocytes we found that expression in thymic stromal cells rather than in thymocytes was critical for T cell development. We found that SOCS3 in thymic epithelial cells (TECs) binds to the E3 ubiquitin ligase TRIM 21 and that Trim21 -/- mice showed increased thymic cellularity. Δsocs3 TECs showed alterations in the expression of genes involved in positive and negative selection and lympho-stromal interactions. SOCS3-dependent signal inhibition of the common gp130 subunit of the IL-6 receptor family was redundant for T cell formation. Together, SOCS3 expression in thymic stroma cells is critical for T cell development and for maintenance of thymus architecture.


Assuntos
Diferenciação Celular/imunologia , Células Estromais/imunologia , Proteína 3 Supressora da Sinalização de Citocinas/imunologia , Linfócitos T/imunologia , Timo/imunologia , Animais , Camundongos , Células Estromais/metabolismo , Proteína 3 Supressora da Sinalização de Citocinas/metabolismo , Timo/metabolismo
12.
Front Immunol ; 12: 655354, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33815417

RESUMO

Inborn errors of thymic stromal cell development and function lead to impaired T-cell development resulting in a susceptibility to opportunistic infections and autoimmunity. In their most severe form, congenital athymia, these disorders are life-threatening if left untreated. Athymia is rare and is typically associated with complete DiGeorge syndrome, which has multiple genetic and environmental etiologies. It is also found in rare cases of T-cell lymphopenia due to Nude SCID and Otofaciocervical Syndrome type 2, or in the context of genetically undefined defects. This group of disorders cannot be corrected by hematopoietic stem cell transplantation, but upon timely recognition as thymic defects, can successfully be treated by thymus transplantation using cultured postnatal thymic tissue with the generation of naïve T-cells showing a diverse repertoire. Mortality after this treatment usually occurs before immune reconstitution and is mainly associated with infections most often acquired pre-transplantation. In this review, we will discuss the current approaches to the diagnosis and management of thymic stromal cell defects, in particular those resulting in athymia. We will discuss the impact of the expanding implementation of newborn screening for T-cell lymphopenia, in combination with next generation sequencing, as well as the role of novel diagnostic tools distinguishing between hematopoietic and thymic stromal cell defects in facilitating the early consideration for thymus transplantation of an increasing number of patients and disorders. Immune reconstitution after the current treatment is usually incomplete with relatively common inflammatory and autoimmune complications, emphasizing the importance for improving strategies for thymus replacement therapy by optimizing the current use of postnatal thymus tissue and developing new approaches using engineered thymus tissue.


Assuntos
Doenças da Imunodeficiência Primária/etiologia , Doenças da Imunodeficiência Primária/metabolismo , Células Estromais/metabolismo , Timo/anormalidades , Timo/metabolismo , Alelos , Animais , Terapia Combinada , Suscetibilidade a Doenças , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Transplante de Órgãos/efeitos adversos , Transplante de Órgãos/métodos , Fenótipo , Doenças da Imunodeficiência Primária/diagnóstico , Doenças da Imunodeficiência Primária/terapia , Células Estromais/patologia , Timo/patologia , Resultado do Tratamento
13.
FASEB J ; 35(5): e21535, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33817835

RESUMO

Thymic epithelial cells (TECs) are indispensable for T cell development, T cell receptor (TCR) repertoire selection, and specific lineage differentiation. Medullary thymic epithelial cells (mTECs), which account for the majority of TECs in adults, are critical for thymocyte selection and self-tolerance. CD74 is a nonpolymorphic transmembrane glycoprotein of major histocompatibility complex class II (MHCII) that is expressed in TECs. However, the exact role of CD74 in regulating the development of mTEC is poorly defined. In this research, we found that loss of CD74 resulted in a significant diminution in the medulla, a selective reduction in the cell number of mature mTECs expressing CD80 molecules, which eventually led to impaired thymic CD4+ T cell development. Moreover, RNA-sequence analysis showed that CD74 deficiency obviously downregulated the canonical nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway in mTECs. Our results suggest that CD74 positively controls mTEC cellularity and maturation partially by activating the canonical NF-κB signaling pathway.


Assuntos
Antígenos de Diferenciação de Linfócitos B/fisiologia , Diferenciação Celular , Células Epiteliais/patologia , Regulação da Expressão Gênica , Antígenos de Histocompatibilidade Classe II/fisiologia , Ativação Linfocitária/imunologia , NF-kappa B/metabolismo , Timo/patologia , Animais , Células Epiteliais/imunologia , Células Epiteliais/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , NF-kappa B/genética , Transdução de Sinais , Timo/imunologia , Timo/metabolismo
14.
Front Immunol ; 12: 635569, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33868260

RESUMO

While there is convincing evidence on the role of Aire-positive medullary thymic epithelial cells (mTEC) in the induction of central tolerance, the nature and function of post-Aire mTECs and Hassall's corpuscles have remained enigmatic. Here we summarize the existing data on these late stages of mTEC differentiation with special focus on their potential to contribute to central tolerance induction by triggering the unique pro-inflammatory microenvironment in the thymus. In order to complement the existing evidence that has been obtained from mouse models, we performed proteomic analysis on microdissected samples from human thymic medullary areas at different differentiation stages. The analysis confirms that at the post-Aire stages, the mTECs lose their nuclei but maintain machinery required for translation and exocytosis and also upregulate proteins specific to keratinocyte differentiation and cornification. In addition, at the late stages of differentiation, the human mTECs display a distinct pro-inflammatory signature, including upregulation of the potent endogenous TLR4 agonist S100A8/S100A9. Collectively, the study suggests a novel mechanism by which the post-Aire mTECs and Hassall's corpuscles contribute to the thymic microenvironment with potential cues on the induction of central tolerance.


Assuntos
Diferenciação Celular , Microambiente Celular , Tolerância Central , Células Epiteliais/metabolismo , Mediadores da Inflamação/metabolismo , Timo/metabolismo , Fatores de Transcrição/metabolismo , Animais , Calgranulina A/metabolismo , Calgranulina B/metabolismo , Pré-Escolar , Células Epiteliais/imunologia , Humanos , Lactente , Camundongos , Proteoma , Proteômica , Timo/imunologia , Receptor 4 Toll-Like/metabolismo
15.
Elife ; 102021 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-33884954

RESUMO

Functional tuning of T cells based on their degree of self-reactivity is established during positive selection in the thymus, although how positive selection differs for thymocytes with relatively low versus high self-reactivity is unclear. In addition, preselection thymocytes are highly sensitive to low-affinity ligands, but the mechanism underlying their enhanced T cell receptor (TCR) sensitivity is not fully understood. Here we show that murine thymocytes with low self-reactivity experience briefer TCR signals and complete positive selection more slowly than those with high self-reactivity. Additionally, we provide evidence that cells with low self-reactivity retain a preselection gene expression signature as they mature, including genes previously implicated in modulating TCR sensitivity and a novel group of ion channel genes. Our results imply that thymocytes with low self-reactivity downregulate TCR sensitivity more slowly during positive selection, and associate membrane ion channel expression with thymocyte self-reactivity and progress through positive selection.


Assuntos
Diferenciação Celular , Antígenos de Histocompatibilidade Classe I/imunologia , Receptores de Antígenos de Linfócitos T/imunologia , Tolerância a Antígenos Próprios , Timócitos/imunologia , Timo/imunologia , Animais , Linhagem da Célula , Regulação da Expressão Gênica , Antígenos de Histocompatibilidade Classe I/metabolismo , Canais Iônicos/genética , Canais Iônicos/metabolismo , Cinética , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Fenótipo , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de Sinais , Timócitos/metabolismo , Timo/crescimento & desenvolvimento , Timo/metabolismo , Transcriptoma
17.
Biomed Res Int ; 2021: 5533210, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33855070

RESUMO

This study elucidated the function role of dietary selenium-enriched yeast (SeY) supplementation on growth performance, immune function, and antioxidant capacity in weaned pigs exposure to oxidative stress. Thirty-two similarity weight pigs were randomly divided into four treatments: (1) nonchallenged control, (2) control+SeY, (3) control+diquat, and (4) control+SeY+diquat. The period of experiment was 21 days; on day 16, pigs were injected with diquat or sterile saline. Results revealed that oxidative stress was notably detrimental to the growth performance of piglets, but SeY supplementation ameliorated this phenomenon, which might be regarding the increasing of body antioxidant capacity and immune functions. In details, SeY supplementation improved the digestibility of crude protein (CP), ash, and gross energy (GE). Moreover, the serum concentrations of proinflammatory cytokines (TNF-α, IL-1ß, and IL-6), glutamic-pyruvic transaminase(GPT), and glutamic-oxaloacetic transaminase (GOT) were reduced via SeY supplemented, and serum concentrations of immunoglobulins A (IgA), IgG, and activities of antioxidant enzymes such as the superoxide dismutase (SOD), catalase (CAT) ,and glutathione peroxidase (GSH-Px) were improved in the diquat-challenged pigs (P < 0.05). In addition, SeY supplementation acutely enhanced the activities of these antioxidant enzymes in the liver and thymus upon diquat challenge, which involved with the upregulation of the critical genes related antioxidant signaling such as the nuclear factor erythroid-derived 2-related factor 2 (Nrf-2) and heme oxygenase-1 (HO-1) (P < 0.05). Importantly, we also found that SeY supplementation apparently reduced the malondialdehyde (MDA) concentrations in the liver, thymus, and serum (P < 0.05). Specifically, the expression levels of TNF-α, IL-6, IL-1ß, Toll-like receptor 4 (TLR-4), and nuclear factor-κB (NF-κB) in the liver and thymus were downregulated by SeY upon diquat challenge. These results suggested that SeY can attenuate oxidative stress-induced growth retardation, which was associated with elevating body antioxidant capacity, immune functions, and suppressed inflammatory response.


Assuntos
Antioxidantes/metabolismo , Estresse Oxidativo , Saccharomyces cerevisiae/fisiologia , Selênio/farmacologia , Suínos/crescimento & desenvolvimento , Suínos/imunologia , Desmame , Alanina Transaminase/sangue , Animais , Aspartato Aminotransferases/sangue , Citocinas/sangue , Digestão , Regulação da Expressão Gênica/efeitos dos fármacos , Imunoglobulina G/sangue , Inflamação/genética , Inflamação/patologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Malondialdeído/sangue , Nutrientes , Estresse Oxidativo/efeitos dos fármacos , Suínos/sangue , Timo/efeitos dos fármacos , Timo/metabolismo , Vísceras/efeitos dos fármacos
18.
Front Immunol ; 12: 652665, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33859647

RESUMO

T cell development is effectively supported in fetal thymus organ cultures (FTOCs), which places thymus lobes atop an air-liquid interface (ALI) culture system. The direct exposure to air is critical for its success, as fetal thymus lobes placed in low oxygen submersion (LOS)-FTOCs fail to support thymocyte development. However, submersion cultures performed in the presence of high concentration of ambient oxygen (60~80%) allow for normal thymocyte development, but the underlying mechanism for this rescue has remained elusive. Here, we show that FOXN1 expression in thymic epithelial cells (TECs) from LOS-FTOCs was greatly reduced compared to conventional ALI-FTOCs. Consequently, the expression of important FOXN1 target genes, including Dll4 and Ccl25, in TECs was extinguished. The loss of DLL4 and CCL25 interrupted thymocyte differentiation and led to CD4+CD8+ cells exiting the lobes, respectively. High oxygen submersion (HOS)-FTOCs restored the expression of FOXN1 and its target genes, as well as maintained high levels of MHCII expression in TECs. In addition, HOS-FTOCs promoted the self-renewal of CD4-CD8-CD44-CD25+ cells, allowing for the continuous generation of later stage thymocytes. Forced FOXN1 expression in TECs rescued thymocyte developmental progression, but not cellularity, in LOS-FTOCs. Given that oxidative stress has been reported to accelerate the onset of age-associated thymic involution, we postulate that regulation of FOXN1 by oxygen and antioxidants may underpin this biological process.


Assuntos
Fatores de Transcrição Forkhead/metabolismo , Linfopoese , Técnicas de Cultura de Órgãos , Oxigênio/metabolismo , Timócitos/citologia , Timócitos/metabolismo , Timo/citologia , Timo/metabolismo , Animais , Biomarcadores , Diferenciação Celular , Imunofenotipagem , Camundongos , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/metabolismo
19.
Front Immunol ; 12: 623280, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33732245

RESUMO

Expression of tissue-restricted antigens (TRAs) in thymic epithelial cells (TECs) ensures negative selection of highly self-reactive T cells to establish central tolerance. Whether some of these TRAs could exert their canonical biological functions to shape thymic environment to regulate T cell development is unclear. Analyses of publicly available databases have revealed expression of transcripts at various levels of many cytokines and cytokine receptors such as IL-15, IL-15Rα, IL-13, and IL-23a in both human and mouse TECs. Ablation of either IL-15 or IL-15Rα in TECs selectively impairs type 1 innate like T cell, such as iNKT1 and γδT1 cell, development in the thymus, indicating that TECs not only serve as an important source of IL-15 but also trans-present IL-15 to ensure type 1 innate like T cell development. Because type 1 innate like T cells are proinflammatory, our data suggest the possibility that TEC may intrinsically control thymic inflammatory innate like T cells to influence thymic environment.


Assuntos
Células Epiteliais/metabolismo , Imunidade Inata , Interleucina-15/metabolismo , Receptores de Interleucina-15/metabolismo , Subpopulações de Linfócitos T/metabolismo , Timócitos/metabolismo , Timo/metabolismo , Animais , Comunicação Celular , Microambiente Celular , Bases de Dados Genéticas , Células Epiteliais/imunologia , Humanos , Interleucina-15/genética , Linfócitos Intraepiteliais/imunologia , Linfócitos Intraepiteliais/metabolismo , Camundongos , Camundongos Knockout , Células T Matadoras Naturais/imunologia , Células T Matadoras Naturais/metabolismo , Receptores de Interleucina-15/genética , Transdução de Sinais , Subpopulações de Linfócitos T/imunologia , Timócitos/imunologia , Timo/citologia , Timo/imunologia
20.
Front Immunol ; 12: 636072, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33746975

RESUMO

The thymus is the primary site of T lymphocyte development, where mutually inductive signaling between lymphoid progenitors and thymic stromal cells directs the progenitors along a well-characterized program of differentiation. Although thymic stromal cells, including thymic epithelial cells (TECs) are critical for the development of T cell-mediated immunity, many aspects of their basic biology have been difficult to resolve because they represent a small fraction of thymus cellularity, and because their isolation requires enzymatic digestion that induces broad physiological changes. These obstacles are especially relevant to the study of metabolic regulation of cell function, since isolation procedures necessarily disrupt metabolic homeostasis. In contrast to the well-characterized relationships between metabolism and intracellular signaling in T cell function during an immune response, metabolic regulation of thymic stromal cell function represents an emerging area of study. Here, we review recent advances in three distinct, but interconnected areas: regulation of mTOR signaling, reactive oxygen species (ROS), and autophagy, with respect to their roles in the establishment and maintenance of the thymic stromal microenvironment.


Assuntos
Metabolismo Energético , Células Epiteliais/metabolismo , Timo/metabolismo , Animais , Autofagia , Microambiente Celular , Células Epiteliais/imunologia , Células Epiteliais/patologia , Humanos , Estresse Oxidativo , Fenótipo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Timo/imunologia , Timo/patologia
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