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ECHO (Extensions for Community Healthcare Outcomes) Autism is a telementoring learning model to increase community capacity for autism-related health care. Seventy-seven pediatric providers (mostly primary care, seeing exclusively Medicaid patient populations) enrolled in 1 year of ECHO Autism Washington. Analysis of self-report surveys showed a significant increase in autism diagnoses made by ECHO providers after 1 year, F(1, 65) = 7.52, P = .008. Providers who attended more sessions reported making more diagnoses, F(2, 613.26), P = .045. Of note, autism diagnoses were not externally validated. The total number of reported barriers reduced, F(2, 61) = 13.5), P < .001, and confidence ratings increased F(2, 60) = 24.21, P < .001. The average number of diagnostic referrals from ECHO providers to the state's largest autism specialty clinic significantly reduced, t(43) = 4.23, P < .001, with significantly fewer diagnostic referrals made during and after ECHO training compared with a comparison group of 28 non-ECHO providers, t(58.77) = -3.36, P < .001. Overall, 1 year of ECHO Autism Washington participation led to significant changes in autism diagnostic practices.
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Alpha-synuclein (αS)-rich Lewy bodies and neurites in the cerebral cortex correlate with the presence of dementia in Parkinson disease (PD) and Dementia with Lewy bodies (DLB), but whether αS influences synaptic vesicle dynamics in human cortical neurons is unknown. Using a new iPSC-based assay platform for measuring synaptic vesicle cycling, we found that in human cortical glutamatergic neurons, increased αS from either transgenic expression or triplication of the endogenous locus in patient-derived neurons reduced synaptic vesicle cycling under both stimulated and spontaneous conditions. Thus, using a robust, easily adopted assay platform, we show for the first time αS-induced synaptic dysfunction in human cortical neurons, a key cellular substrate for PD dementia and DLB.
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Autistic adolescents and adults commonly experience mental health concerns; however, mental health clinicians may hold implicit stigmatizing views of autism that contribute to case conceptualization and treatment goal setting that align more with caregivers' than clients' goals. This impingement on client autonomy is concerning, problematic, and potentially harmful for autistic clients who are of an age to set their own treatment agenda regardless of co-occurring intellectual disability and/or language delays. An application of the shared decision-making framework, an evidence-based tool for promoting client autonomy, can help to avoid these challenges in treatment. In this perspective, we use a case vignette as an anchor for discussing the imperative of honoring autistic clients' autonomy in mental health treatment and guiding shared decision-making to reduce stigma, promote autonomy, and increase collaborative care for autistic clients in mental health treatment.
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The individual behavioral traits of predators and prey sometimes determine the outcome of their interactions. Here, we examine whether changes to habitat complexity alter the effects of predator and prey behavior on their survival rates. Specifically, we test whether behavioral traits (activity level, boldness, and perch height) measured in predators and prey or multivariate behavioral volumes best predict the survival rates of both trophic levels in staged mesocosms with contrasting structural complexity. Behavioral volumes and hypervolumes are a composite group-level behavioral diversity metric built from the individual-level behavioral traits we measured in predators and prey. We stocked mesocosms with a host plant and groups of cannibalistic predators (n = 5 mantises/mesocosm) and their prey (n = 15 katydids/mesocosm), and mesocosms varied in the presence/absence of additional non-living climbing structures. We found that mantis survival rates were unrelated to any behavioral metric considered here, but were higher in structurally complex mesocosms. Unexpectedly, katydids were more likely to survive when mantis groups occupied larger behavioral volumes, indicating that more behaviorally diverse predator groups are less lethal. Katydid mortality was also increased when both predators and prey exhibited higher average perch heights, but this effect was increased by the addition of supplemental structure. This is consistent with the expectation that structural complexity increases the effect of intraspecific behavioral variation on prey survival rates. Collectively, these results convey that the effects of predator and prey behavior on prey survival could depend highly on the environment in which they are evaluated.
Assuntos
Percas , Comportamento Predatório , Animais , Canibalismo , Ecossistema , Taxa de SobrevidaRESUMO
BACKGROUND: Minnesota has an ethnically diverse labor force, with the largest number of refugees per capita in the United States. In recent years, Minnesota has been and continues to be a major site for immigrant and refugee resettlement in the United States, with a large population of both immigrant and native born Hmong, Hispanic, and East Africans. This study seeks to evaluate the injury risk among the evolving minority workforce in the Minnesota Twin Cities region. METHODS: A retrospective cohort study identifying work-related injuries following pre-employment examinations was performed using electronic health records from a large multi-clinic occupational medicine practice. Preplacement examinations and subsequent work-related injuries were pulled from the electronic health record using representative ICD-10 codes for surveillance examinations and injuries. This study included patient records collected over a 2-year period from January 1, 2015, through December, 2016. The patients in this cohort worked in a wide-array of occupations including production, assembly, construction, law enforcement, among others. RESULTS: Hispanic minority workers were twice as likely to be injured at work compared with White workers. Hispanics were 2.89 times more likely to develop back injuries compared with non-Hispanic workers, and 1.86 times more likely to develop upper extremity injuries involving the hand, wrist, or elbow. CONCLUSION: Clinical practice data shows that Hispanic workers are at increased risk for work-related injuries in Minnesota. They were especially susceptible to back and upper extremity injuries. Lower injury rates in non-Hispanic minority workers, may be the result of injury underreporting and require further investigation.
Assuntos
Traumatismos do Braço/etnologia , Asiático/estatística & dados numéricos , Lesões nas Costas/etnologia , Negro ou Afro-Americano/estatística & dados numéricos , Traumatismos da Mão/etnologia , Hispânico ou Latino/estatística & dados numéricos , Traumatismos Ocupacionais/etnologia , Lesões do Ombro/etnologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Minnesota/epidemiologia , Grupos Minoritários/estatística & dados numéricos , Medicina do Trabalho , Modelos de Riscos Proporcionais , Estudos Retrospectivos , População Branca/estatística & dados numéricos , Adulto JovemRESUMO
The angiotensin-converting enzyme (ACE) is a peptidase that is involved in the synthesis of Angiotensin II, the bioactive component of the renin-angiotensin system. A growing body of literature argues for a beneficial impact of ACE inhibitors (ACEi) on age-associated metabolic disorders, mediated by cellular changes in reactive oxygen species (ROS) that improve mitochondrial function. Yet, our understanding of the relationship between ACEi therapy and metabolic parameters is limited. Here, we used three genetically diverse strains of Drosophila melanogaster to show that Lisinopril treatment reduces thoracic ROS levels and mitochondrial respiration in young flies, and increases mitochondrial content in middle-aged flies. Using untargeted metabolomics analysis, we also showed that Lisinopril perturbs the thoracic metabolic network structure by affecting metabolic pathways involved in glycogen degradation, glycolysis, and mevalonate metabolism. The Lisinopril-induced effects on mitochondrial and metabolic parameters, however, are genotype-specific and likely reflect the drug's impact on nutrient-dependent fitness traits. Accordingly, we found that Lisinopril negatively affects survival under nutrient starvation, an effect that can be blunted by genotype and age in a manner that partially mirrors the drug-induced changes in mitochondrial respiration. In conclusion, our results provide novel and important insights into the role of ACEi in cellular metabolism.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/farmacologia , Drosophila melanogaster/efeitos dos fármacos , Lisinopril/farmacologia , Redes e Vias Metabólicas/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Envelhecimento/efeitos dos fármacos , Animais , Drosophila melanogaster/genética , Drosophila melanogaster/fisiologia , Genótipo , Masculino , Metaboloma/efeitos dos fármacos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Peptidil Dipeptidase A/metabolismo , Espécies Reativas de Oxigênio/metabolismoRESUMO
Our understanding of the electrical properties of cell membranes is derived from experiments where the membrane is exposed to a perturbation (in the form of a time-dependent voltage or current change) and information is extracted from the measured output. The interpretation of such electrical recordings consists in finding an electronic equivalent that would show the same or similar response as the biological system. In general, however, there is no unique circuit configuration, which can explain a single electrical recording and the choice of an electric model for a biological system is based on complementary information (most commonly structural information) of the system investigated. Most of the electrophysiological data on cell membranes address the functional role of protein channels while assuming that the lipid matrix is an insulator with constant capacitance. However, close to their melting transition the lipid bilayers are no inert insulators. Their conductivity and their capacitance are nonlinear functions of both voltage, area and volume density. This has to be considered when interpreting electrical data. Here we show how electric data commonly interpreted as gating currents of proteins and inductance can be explained by the nonlinear dynamics of the lipid matrix itself.
RESUMO
Biological membranes are capacitors that can be charged by applying a field across the membrane. The charges on the capacitor exert a force on the membrane that leads to electrostriction, i.e. a thinning of the membrane. Since the force is quadratic in voltage, negative and positive voltage have an identical influence on the physics of symmetric membranes. However, this is not the case for a membrane with an asymmetry leading to a permanent electric polarization. Positive and negative voltages of identical magnitude lead to different properties. Such an asymmetry can originate from a lipid composition that is different on the two monolayers of the membrane, or from membrane curvature. The latter effect is called 'flexoelectricity'. As a consequence of permanent polarization, the membrane capacitor is discharged at a voltage different from zero. This leads to interesting electrical phenomena such as outward or inward rectification of membrane permeability. Here, we introduce a generalized theoretical framework, that treats capacitance, polarization, flexoelectricity, piezoelectricity and thermoelectricity in the same language. We show applications to electrostriction, membrane permeability and piezoelectricity and thermoelectricity close to melting transitions, where such effects are especially pronounced.
Assuntos
Membrana Celular/química , Capacitância Elétrica , Animais , Fenômenos Biomecânicos , Humanos , Bicamadas Lipídicas/química , Modelos Biológicos , PermeabilidadeRESUMO
BACKGROUND: Thermal safety standards for the use of chemical, biological, radiological, and nuclear (CBRN) ensembles have been established for various US occupations, but not for law enforcement personnel. OBJECTIVES: We examined thermal strain levels of 30 male US law enforcement personnel who participated in CBRN field training in Arizona, Florida, and Massachusetts. METHODS: Physiological responses were examined using unobtrusive heart rate (HR) monitors and a simple thermoregulatory model to predict core temperature (Tc) using HR and environment. RESULTS: Thermal strain levels varied by environments, activity levels, and type of CBRN ensemble. Arizona and Florida volunteers working in hot-dry and hot-humid environment indicated high heat strain (predicted max Tc>38·5°C). The cool environment of Massachusetts reduced thermal strain although thermal strains were occasionally moderate. CONCLUSIONS: The non-invasive method of using physiological monitoring and thermoregulatory modeling could improve law enforcement mission to reduce the risk of heat illness or injury.
Assuntos
Transtornos de Estresse por Calor/etiologia , Capacitação em Serviço/métodos , Doenças Profissionais/etiologia , Exposição Ocupacional/efeitos adversos , Polícia , Equipamentos de Proteção , Adulto , Temperatura Corporal , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Saúde OcupacionalRESUMO
Francisella tularensis is a bacterial pathogen that uses host-derived PGE2 to subvert the host's adaptive immune responses in multiple ways. Francisella-induced PGE2 acts directly on CD4 T cells to blunt production of IFN-γ. Francisella-induced PGE2 can also elicit production of a >10 kDa soluble host factor termed FTMØSN (F. tularensismacrophage supernatant), which acts on IFN-γ pre-activated MØ to down-regulate MHC class II expression via a ubiquitin-dependent mechanism, blocking antigen presentation to CD4 T cells. Here, we report that FTMØSN-induced down-regulation of MØ class II is the result of the induction of MARCH1, and that MØ expressing MARCH1 "resistant" class II molecules are resistant to FTMØSN-induced class II down-regulation. Since PGE2 can induce IL-10 production and IL-10 is the only reported cytokine able to induce MARCH1 expression in monocytes and dendritic cells, these findings suggested that IL-10 is the active factor in FTMØSN. However, use of IL-10 knockout MØ established that IL-10 is not the active factor in FTMØSN, but rather that Francisella-elicited PGE2 drives production of a >10 kDa host factor distinct from IL-10. This factor then drives MØ IL-10 production to induce MARCH1 expression and the resultant class II down-regulation. Since many human pathogens such as Salmonella typhi, Mycobacterium tuberculosis and Legionella pneumophila also induce production of host PGE2, these results suggest that a yet-to-be-identified PGE2-inducible host factor capable of inducing IL-10 is central to the immune evasion mechanisms of multiple important human pathogens.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Francisella tularensis/imunologia , Antígenos de Histocompatibilidade Classe II/biossíntese , Interleucina-10/biossíntese , Macrófagos/imunologia , Ubiquitina-Proteína Ligases/biossíntese , Dinoprostona/fisiologia , Regulação para Baixo , Humanos , Interleucina-10/genética , Macrófagos/metabolismo , Ubiquitina-Proteína Ligases/fisiologia , Regulação para CimaRESUMO
SNARE-mediated membrane fusion is a pivotal event for a wide-variety of biological processes. SNAP-25, a neuron-specific SNARE protein, has been well-characterized and mouse embryos lacking Snap25 are viable. However, the phenotype of mice lacking SNAP-23, the ubiquitously expressed SNAP-25 homolog, remains unknown. To reveal the importance of SNAP-23 function in mouse development, we generated Snap23-null mice by homologous recombination. We were unable to obtain newborn SNAP-23-deficient mice, and analysis of pre-implantation embryos from Snap23(Δ/wt) matings revealed that Snap23-null blastocysts were dying prior to implantation at embryonic day E3.5. Thus these data reveal a critical role for SNAP-23 during embryogenesis.
Assuntos
Implantação do Embrião , Perda do Embrião/metabolismo , Perda do Embrião/patologia , Deleção de Genes , Proteínas Qb-SNARE/deficiência , Proteínas Qc-SNARE/deficiência , Alelos , Animais , Blastocisto/citologia , Blastocisto/metabolismo , Cruzamento , Morte Celular , Feminino , Marcação de Genes , Heterozigoto , Camundongos , Camundongos Endogâmicos C57BL , Gravidez , Proteínas Qb-SNARE/metabolismo , Proteínas Qc-SNARE/metabolismoRESUMO
The expression and turnover of MHC class II-peptide complexes (pMHC-II) on the surface of dendritic cells (DCs) is essential for their ability to activate CD4 T cells efficiently. The half-life of surface pMHC-II is significantly greater in activated (mature) DCs than in resting (immature) DCs, but the molecular mechanism leading to this difference remains unknown. We now show that ubiquitination of pMHC-II by the E3 ubiquitin ligase membrane-associated RING-CH 1 (March-I) regulates surface expression, intracellular distribution, and survival of pMHC-II in DCs. DCs isolated from March-I-KO mice express very high levels of pMHC-II on the plasma membrane even before DC activation. Although ubiquitination does not affect the kinetics of pMHC-II endocytosis from the surface of DCs, the survival of pMHC-II is enhanced in DCs obtained from March-I-deficient and MHC-II ubiquitination-mutant mice. Using pMHC-II-specific mAb, we show that immature DCs generate large amounts of pMHC-II that are remarkably stable under conditions in which pMHC-II ubiquitination is blocked. Thus, the cellular distribution and stability of surface pMHC-II in DCs is regulated by ubiquitin-dependent degradation of internalized pMHC-II.
Assuntos
Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Regulação da Expressão Gênica/imunologia , Antígenos de Histocompatibilidade Classe II/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Animais , Anticorpos Monoclonais , Células Dendríticas/citologia , Immunoblotting , Imunoprecipitação , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microscopia de Fluorescência , Transfecção , Ubiquitina-Proteína Ligases/genética , UbiquitinaçãoRESUMO
The expression of MHC class II (MHC-II) on the surface of antigen-presenting cells, such as dendritic cells (DCs), is tightly regulated during cellular activation. Many cells, including DCs, are activated following stimulation of innate Toll-like receptors (TLRs) by products of microorganisms. In the resting (immature) state, MHC-II is ubiquitinated in immature DCs and is rapidly degraded; however, after activation of these cells with MyD88-dependent TLR ligands, MHC-II ubiquitination is blocked, and MHC-II survival is prolonged. We now show that DC activation using MyD88-dependent TLR ligands, MyD88-independent TLR ligands, and even infection with the intracellular parasite Toxoplasma gondii leads to identical changes in MHC-II expression, ubiquitination, and surface stability, revealing a conserved role for enhanced MHC-II stability after DC activation by different stimuli.
Assuntos
Células Dendríticas/citologia , Antígenos de Histocompatibilidade Classe II/química , Animais , Membrana Celular/metabolismo , Separação Celular , Células Cultivadas , Citometria de Fluxo , Humanos , Ligantes , Camundongos , Monócitos/citologia , Propriedades de Superfície , Receptores Toll-Like/metabolismo , Toxoplasma/metabolismo , Regulação para CimaRESUMO
PURPOSE: This study identifies risk factors, including incident disability, for the use of assistive devices (ADs) among older people. DESIGN AND METHODS: Three waves of data from the National Long-Term Care Survey (NLTCS) are used to examine whether upper and lower body disability lead to use of ADs (both number of devices used and number of activities of daily living domains for which ADs are used). Predictors of AD use include demographic variables, body mass index, and disability (both initial and incident). Relationships are estimated with negative binomial regression models. RESULTS: Lower body disability, advanced age, and obesity are consistent predictors of the number of ADs used. An interaction between age and incident disability revealed the highest rate of adoption among the younger respondents who experienced increases in disability. IMPLICATIONS: Many older adults use ADs in response to the disablement process. In addition to need driven by rising disability, obese older adults use more ADs. Results from this study clarify who and why ADs are adopted by older persons and should facilitate effective intervention by health care personnel and caregivers.
Assuntos
Avaliação Geriátrica , Tecnologia Assistiva/estatística & dados numéricos , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Coleta de Dados , Feminino , Humanos , MasculinoRESUMO
Lewy bodies are mainly composed of alpha-synuclein (SNCA) and specific mutations in SNCA gene are related to familial forms of Parkinson's disease (PD). The purpose of our study was to generate a mouse line with A30P knock-in point mutation in SNCA gene and to test if a single point-mutation is able to turn otherwise normal SNCA into a toxic form. The behavioral profile of SNCA A30P mice was followed for 16 months. Generally, these mice are healthy and viable without any obvious abnormalities. Starting from the age of 13 months mice developed a significant deficit in motor performance tests related to nigrostriatal function (ink-test and beam walk). In other tests (motility boxes, rotarod) mice continuously performed normally. Moreover, SNCA A30P mice expressed the altered sensitivity to VMAT2 inhibitor reserpine, possibly reflecting a functional deficiency of dopamine. Indeed, mice at 15 months of age had significantly reduced levels of dopamine and its major metabolite DOPAC in the striatum, and reduced levels of dopamine in the mesolimbic system. The present study confirms that SNCA plays an important role in the development of PD and an insertion of a single point mutation is sufficient to generate age-related decline in specific motor performance. The generated mouse line has a potential to become a model for PD with comparable time course and phenotype.
Assuntos
Corpo Estriado/fisiologia , Mutação Puntual/genética , Substância Negra/fisiologia , alfa-Sinucleína/genética , Fatores Etários , Envelhecimento/genética , Animais , Dopamina/deficiência , Dopamina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Transtornos das Habilidades Motoras/genética , Transtornos das Habilidades Motoras/metabolismo , Doença de Parkinson/genética , Doença de Parkinson/metabolismoRESUMO
BACKGROUND: Sp4 is a zinc finger transcription factor which is closely related to Sp1 and Sp3. All three proteins recognize the same DNA elements and can act as transcriptional activators through glutamine-rich activation domains. Unlike Sp1 and Sp3, which are ubiquitous proteins, Sp4 is highly abundant in the central nervous system, but also detectable in many other tissues. RESULTS: We have disrupted the mouse Sp4 gene by a targeted deletion of the exons encoding the N-terminal activation domains. Sp4 knockout mice show a complete absence of Sp4 expression. They develop until birth without obvious abnormalities. After birth, two-thirds die within 4 weeks. Surviving mice are growth retarded. Male Sp4null mice do not breed. The cause for the breeding defect remains obscure since they show complete spermatogenesis. In addition, pheromone receptor genes in the vomeronasal organ appear unaffected. Female Sp4null mice have a smaller thymus, spleen and uterus. In addition, they exhibit a pronounced delay in sexual maturation. CONCLUSIONS: The phenotype of the Sp4null mice differs significantly from those described for Sp1-/- and Sp3-/- mice. Thus, the structural similarities, the common recognition motif and the overlapping expression pattern of these three transcription factors do not reflect similar physiological functions.
Assuntos
Fatores de Transcrição/fisiologia , Alelos , Animais , Linhagem Celular , Mapeamento Cromossômico , Clonagem Molecular , DNA/metabolismo , Embrião de Mamíferos/metabolismo , Desenvolvimento Embrionário e Fetal , Feminino , Marcação de Genes , Crescimento/fisiologia , Transtornos do Crescimento/genética , Homozigoto , Masculino , Camundongos , Camundongos Knockout , Mutação , Reprodução , Maturidade Sexual/fisiologia , Fator de Transcrição Sp4 , Distribuição Tecidual , Fatores de Transcrição/deficiência , Fatores de Transcrição/genética , Dedos de ZincoRESUMO
The zinc finger transcription factor GATA-3 is of critical importance for early T cell development and commitment of Th2 cells. To study the role of GATA-3 in early T cell development, we analyzed and modified GATA-3 expression in vivo. In mice carrying a targeted insertion of a lacZ reporter on one allele, we found that GATA-3 transcription in CD4(+)CD8(+) double-positive thymocytes correlated with the onset of positive selection events, i.e., TCRalphabeta up-regulation and CD69 expression. LacZ expression remained high ( approximately 80% of cells) during maturation of CD4 single-positive (SP) cells in the thymus, but in developing CD8 SP cells the fraction of lacZ-expressing cells decreased to <20%. We modified this pattern by enforced GATA-3 expression driven by the CD2 locus control region, which provides transcription of GATA-3 throughout T cell development. In two independent CD2-GATA3-transgenic lines, approximately 50% of the mice developed thymic lymphoblastoid tumors that were CD4(+)CD8(+/low) and mostly CD3(+). In tumor-free CD2-GATA3-transgenic mice, the total numbers of CD8 SP cells in the thymus were within normal ranges, but their maturation was hampered, as indicated by increased apoptosis of CD8 SP cells and a selective deficiency of mature CD69(low)HSA(low) CD8 SP cells. In the spleen and lymph nodes, the numbers of CD8(+) T cells were significantly reduced. These findings indicate that GATA-3 supports development of the CD4 lineage and inhibits maturation of CD8 SP cells in the thymus.
Assuntos
Linfócitos T CD8-Positivos/citologia , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Inibidores do Crescimento/biossíntese , Linfoma de Células T/imunologia , Subpopulações de Linfócitos T/citologia , Neoplasias do Timo/imunologia , Transativadores/biossíntese , Transativadores/genética , Animais , Antígenos CD2/genética , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Linfócitos T CD8-Positivos/patologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Linhagem da Célula/genética , Linhagem da Célula/imunologia , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/fisiologia , Regulação para Baixo/genética , Regulação para Baixo/imunologia , Fator de Transcrição GATA3 , Regulação da Expressão Gênica/imunologia , Inibidores do Crescimento/antagonistas & inibidores , Inibidores do Crescimento/genética , Inibidores do Crescimento/fisiologia , Humanos , Região de Controle de Locus Gênico/imunologia , Linfonodos/patologia , Linfoma de Células T/etiologia , Linfoma de Células T/patologia , Linfopenia/genética , Linfopenia/imunologia , Camundongos , Camundongos Transgênicos , Receptores de Antígenos de Linfócitos T alfa-beta/biossíntese , Baço/patologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Subpopulações de Linfócitos T/patologia , Neoplasias do Timo/etiologia , Neoplasias do Timo/patologia , Transativadores/antagonistas & inibidores , Transativadores/fisiologia , Transgenes/imunologia , Regulação para Cima/genética , Regulação para Cima/imunologiaRESUMO
The transcription factor GATA-3 is essential for early T cell development and differentiation of naive CD4(+) T cells into Th2 effector cells. To study the function of GATA-3 during T cell-mediated immune responses in vivo, we investigated CD2-GATA3-transgenic mice in which GATA-3 expression is driven by the CD2 locus control region. Both in the CD4(+) and the CD8(+) T cell population the proportion of cells exhibiting a CD44(high)CD45RB(low)CD62L(low) Ag-experienced phenotype was increased. In CD2-GATA3-transgenic mice, large fractions of peripheral CD4(+) T cells expressed the IL-1 receptor family member T1/ST2, indicative of advanced Th2 commitment. Upon in vitro T cell stimulation, the ability to produce IL-2 and IFN-gamma was decreased. Moreover, CD4(+) T cells manifested rapid secretion of the Th2 cytokines IL-4, IL-5, and IL-10, reminiscent of Th2 memory cells. In contrast to wild-type CD4(+) cells, which lost GATA-3 expression when cultured under Th1-polarizing conditions, CD2-GATA3-transgenic CD4(+) cells maintained expression of GATA-3 protein. Under Th1 conditions, cellular proliferation of CD2-GATA3-transgenic CD4(+) cells was severely hampered, IFN-gamma production was decreased and Th2 cytokine production was increased. Enforced GATA-3 expression inhibited Th1-mediated in vivo responses, such as Ag-specific IgG2a production or a delayed-type hypersensitivity response to keyhole limpet hemocyanin. Collectively, these observations indicate that enforced GATA-3 expression selectively inhibits Th1 differentiation and induces Th2 differentiation. The increased functional capacity to secrete Th2 cytokines, along with the increased expression of surface markers for Ag-experienced Th2-committed cells, would argue for a role of GATA-3 in Th2 memory formation.
Assuntos
Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Inibidores do Crescimento/biossíntese , Inibidores do Crescimento/genética , Proteínas de Membrana , Biossíntese de Proteínas , Células Th1/citologia , Células Th2/citologia , Células Th2/metabolismo , Transativadores/biossíntese , Transativadores/genética , Animais , Antígenos CD2/genética , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Polaridade Celular/genética , Polaridade Celular/imunologia , Células Cultivadas , Citocinas/biossíntese , Citocinas/metabolismo , Proteínas de Ligação a DNA/fisiologia , Regulação para Baixo/genética , Regulação para Baixo/imunologia , Epitopos de Linfócito T/biossíntese , Fator de Transcrição GATA3 , Switching de Imunoglobulina/genética , Imunoglobulina G/biossíntese , Proteína 1 Semelhante a Receptor de Interleucina-1 , Região de Controle de Locus Gênico/imunologia , Linfonodos/citologia , Ativação Linfocitária/genética , Contagem de Linfócitos , Linfoma de Células T/genética , Linfoma de Células T/imunologia , Camundongos , Camundongos Transgênicos , Receptores de Interleucina , Baço/citologia , Subpopulações de Linfócitos T/citologia , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Células Th2/imunologia , Timo/citologia , Neoplasias do Timo/genética , Neoplasias do Timo/imunologia , Transativadores/fisiologiaRESUMO
Patterning the vertebrate ear requires the coordinated expression of genes that are involved in morphogenesis, neurogenesis, and hair cell formation. The zinc finger gene GATA-3 is expressed both in the inner ear and in afferent and efferent auditory neurons. Specifically, GATA-3 is expressed in a population of neurons in rhombomere 4 that extend their axons across the floor plate of rhombomere 4 (r4) at embryonic day 10 (E10) and reach the sensory epithelia of the ear by E13.5. The distribution of their cell bodies corresponds to that of the cell bodies of the cochlear and vestibular efferent neurons as revealed by labeling with tracers. Both GATA-3 heterozygous and GATA-3 null mutant mice show unusual axonal projections, such as misrouted crossing fibers and fibers in the facial nerve, that are absent in wild-type littermates. This suggests that GATA-3 is involved in the pathfinding of efferent neuron axons that navigate to the ear. In the ear, GATA-3 is expressed inside the otocyst and the surrounding periotic mesenchyme. The latter expression is in areas of branching of the developing ear leading to the formation of semicircular canals. Ears of GATA-3 null mutants remain cystic, with a single extension of the endolymphatic duct and no formation of semicircular canals or saccular and utricular recesses. Thus, both the distribution of GATA-3 and the effects of null mutations on the ear suggest involvement of GATA-3 in morphogenesis of the ear. This study shows for the first time that a zinc finger factor is involved in axonal navigation of the inner ear efferent neurons and, simultaneously, in the morphogenesis of the inner ear.