Associação do polimorfismo de IL-13 (+1398A/G) com a asma e a ancestralidade genômica / Association of IL-13 (+1398A/G) gene polymorphisms with asthma and genomic ancestry

Introdução: A asma é uma doença complexa, resultante da interação entre fatores genéticos e ambientais. A expressão aumentada de genes relacionados à inflamação define as alterações celulares e estruturais do aparelho respiratório, enquanto o meio ambiente modula os diferentes fenótipos asmáticos. Os produtos dessas células envolvidos na inflamação incluem citocinas, como a interleucina13 (IL-13), que está relacionada com a síntese direta de IgE, imunoglobulina essencial na patogênese da asma. Há divergências entre a prevalência da asma e o grupo étnico estudado, desta forma, o uso de Marcadores Informativos de Ancestralidade (AIM ­ Ancestry Informative Markers) possibilita a caracterização da ancestralidade genômica de diferentes populações. Objetivos: Verificar a associação entre polimorfismos do gene IL-13R com a ancestralidade genômica e a asma em uma população no sul da Bahia. Métodos: Foram genotipadas 320 amostras, sendo 114 casos, e 206 controles, utilizando o método de PCR e PCR/RFLP em sete AIMs (Sb19.3, APO, AT3, RB2300, LPL, CKMM e PV92) que apresentam elevado diferencial de frequência alélica entre africanos, ameríndios e europeu, e um polimorfismo no receptor de IL-13 (IL-13RA1). Resultados: Os resultados desse estudo mostraram que a maior contribuição foi ameríndia, tanto para os casos (37,42%), como para os controles (50,52%), demonstrando que há diferenças nas contribuições étnicas das amostras da região estudada. O polimorfismo no receptor de IL-13 (IL- 13RA1) apresentou associação significativa com rinite e história familiar. Conclusões: A heterogeneidade da composição étnica das amostras pode ter influenciado na não associação das duas variáveis: níveis de IgE sérico e histórico familiar, e a presença do polimorfismo no receptor da IL-13RA1, e aponta a necessidade de realização do controle genômico.

Introduction: Asthma is a complex disease resulting from the interaction between genetic and environmental factors. Increased expression of inflammatory genes defines cellular and structural changes in the respiratory tract, while the environment modulates the different asthmatic phenotypes. Cell products involved in inflammation include cytokines, such as interleukin-13 (IL-13), which is related to the direct synthesis of IgE, an immunoglobulin that plays a key role in the pathogenesis of asthma. Because there is divergence of asthma prevalence between different ethnic groups, the use of ancestry informative markers (AIMs) allows for the characterization of genomic ancestry in different populations. Objectives: To examine the association of IL-13R gene polymorphisms with genomic ancestry and asthma in a population from the south of Bahia. Methods: A total of 320 samples, 114 cases and 206 controls, were genotyped using PCR and PCR/RFLP methods for 7 AIMs (Sb19.3, APO, AT3, RB2300, LPL, CKMM, and PV92) that showed a high allele frequency differential between Africans, Amerindians, and Europeans and 1 polymorphism in the IL-13 receptor (IL-13RA1). Results: Amerindian ancestry provided the greatest contribution in both cases (37.42%) and controls (50.52%), indicating that there are differences in the ethnic contribution of the samples from the study region. The IL-13 receptor (IL-13RA1) polymorphism was significantly associated with rhinitis and family history. Conclusions: Heterogeneity in the ethnic composition of the samples may have influenced the non-association of serum IgE levels and family history with the presence of IL-13RA1 receptor polymorphism, and the results point to the need for genomic control.

The impact of interleukin-13 receptor expressions in cell migration of astrocytomas / O impacto da expressão dos receptores de interleucina-13 na migração celular em astrocitomas

INTRODUCTION: Astrocytomas are common brain tumors. Increased expression levels of Interleukin-13 Receptor α2 (IL-13RA2) have been reported in astrocytomas. The Interleukin-13 signaling pathway may be associated with cell migration when binding to Interleukin-13 Receptor α1. OBJECTIVE: To investigate Interleukin-13 Receptor α1 (IL-13RA1) and IL13RA2 expression levels in human diffusely infiltrative astrocytomas and test the involvement of Interleukin-13 levels in cell migration in two glioblastoma cell lines. METHODS: IL13RA expression levels were accessed by quantitative real time PCR in 128 samples of astrocytomas and 18 samples of non-neoplastic brain tissues from temporal lobe epilepsy surgery. The impact of IL-13 levels (10 and 20 ng/mL) on cell migration was analyzed by the wound assay in U87MG and A172 cells. RESULTS: Glioblastoma presented higher IL13RA1 and IL13RA2 expression levels compared to lower grades astrocytomas and to non-neoplastic cases. U87MG and A172 cells presented higher expression levels of IL-13RA1 vs. IL-13RA2. A significant difference in migration rate was observed in A172 cells treated with 10 ng/mL of IL-13 vs. control: treated cells presented slower migration than non-treated cells. U87MG cells treated with IL-13 20ng/mL presented slower migration than non-treated cells. This indicates that the IL13Rα1 signaling pathway was not activated, indeed inhibited by the decoy IL-13Rα2, slowing cell migration. This impact occurred with a lesser concentration of IL-13 on the A172 than on the U87MG cell line, because A172 cells have a higher IL-13RA2/A1 ratio. CONCLUSION: The present results suggest IL-13 receptors as possible targets to decrease tumor cell migration.

INTRODUÇÃO Astrocitomas são os tumores cerebrais mais frequentes. Nestes tumores foi observada maior expressão do receptor de Interleucina-13 α2 (IL13RA2). A cascata de sinalização da Interleucina-13 pode estar associada com a migração celular, após sua ligação com o receptor de Interleucina-13 α1 (IL13Rα1). OBJETIVO: Investigar os níveis de expressão dos receptores de Interleucina-13 (IL13RA1 e IL13RA2) em astrocitomas difusamente infiltrativos e avaliar o envolvimento da Interleucina-13 na migração celular de duas linhagens de glioblastoma. MÉTODOS: A expressão dos receptores IL13RA foi analisada por PCR em tempo real, em 128 amostras de astrocitomas e 18 amostras de tecido cerebral não neoplásico, provenientes de cirurgia de epilepsia do lobo temporal. E o impacto da quantidade de IL-13 (10ng/ml e 20ng/ml) em ensaio de migração celular. RESULTADOS: As amostras de Glioblastoma apresentaram maior expressão de IL13RA1 and IL13RA2 comparados com astrocitomas de baixo grau e os casos não-neoplásicos. Nas células U87MG e A172 foi observado maior nível de expressão de IL-13RA1 do que IL-13RA2. Uma diferença significativa na taxa de migração foi obtida em células A172 tratadas com 10 ng/mL comparadas com o controle: as células tratadas apresentaram menor migração que as células não tratadas. As células U87MG tratadas com 20ng/mL de IL-13 apresentaram menor migração celular que as células não tratadas. A diferença na migração celular indica que o caminho de sinalização de IL13Rα1 não foi ativado e foi inibido pelo IL-13Rα2, diminuindo a migração celular. Esse impacto ocorreu com uma concentração menor de IL-13 nas células A172 ao contrário da U87MG, porque as células A172 possuem uma razão IL-13RA2/A1 maior. CONCLUSÃO: os resultados sugerem que os receptores de IL-13 podem ser utilizados como possíveis alvos para a diminuição da migração celular tumoral.

Antigen-specific immune responses and clinical outcome after vaccination with glioma-associated antigen peptides and polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose in children with newly diagnosed malignant brainstem and nonbrainstem gliomas.

PURPOSE: Diffuse brainstem gliomas (BSGs) and other high-grade gliomas (HGGs) of childhood carry a dismal prognosis despite current treatments, and new therapies are needed. Having identified a series of glioma-associated antigens (GAAs) commonly overexpressed in pediatric gliomas, we initiated a pilot study of subcutaneous vaccinations with GAA epitope peptides in HLA-A2-positive children with newly diagnosed BSG and HGG. PATIENTS AND METHODS: GAAs were EphA2, interleukin-13 receptor alpha 2 (IL-13Rα2), and survivin, and their peptide epitopes were emulsified in Montanide-ISA-51 and given every 3 weeks with intramuscular polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose for eight courses, followed by booster vaccinations every 6 weeks. Primary end points were safety and T-cell responses against vaccine-targeted GAA epitopes. Treatment response was evaluated clinically and by magnetic resonance imaging. RESULTS: Twenty-six children were enrolled, 14 with newly diagnosed BSG treated with irradiation and 12 with newly diagnosed BSG or HGG treated with irradiation and concurrent chemotherapy. No dose-limiting non-CNS toxicity was encountered. Five children had symptomatic pseudoprogression, which responded to dexamethasone and was associated with prolonged survival. Only two patients had progressive disease during the first two vaccine courses; 19 had stable disease, two had partial responses, one had a minor response, and two had prolonged disease-free status after surgery. Enzyme-linked immunosorbent spot analysis in 21 children showed positive anti-GAA immune responses in 13: to IL-13Rα2 in 10, EphA2 in 11, and survivin in three. CONCLUSION: GAA peptide vaccination in children with gliomas is generally well tolerated and has preliminary evidence of immunologic and clinical responses. Careful monitoring and management of pseudoprogression is essential.

IL-4 and IL-13 regulate the induction of indoleamine 2,3-dioxygenase activity and the control of Toxoplasma gondii replication in human fibroblasts activated with IFN-gamma.

The ability of up-regulatory [recombinant (r) IFN-gamma, rIFN-beta and rTNF-alpha] and down-regulatory (rIL-4, rIL-10 and rIL-13) cytokines to control the expression of indoleamine 2,3-dioxygenase (INDO) and anti-Toxoplasma activity in the human fibrosarcoma cell line 2C4 was evaluated. Activation of fibroblasts with rIFN-gamma, rIFN-beta and rTNF-alpha resulted in augmentation of INDO expression and activity leading to 40.0, 25.0 and 27.0 % inhibition of tachyzoite growth, respectively. An additive effect was observed when host cells were incubated with rIFN-gamma plus rTNF-alpha. With regard to the down-regulatory cytokines we observed that IL-4 as well as IL-13, but not IL-10, induced significant inhibition of IFN-gamma-induced control of parasite replication, INDO mRNA expression and tryptophan catabolism. Similarly, IL-4 but not IL-10 inhibited the cell surface expression of HLA-DR and CD2 induced by IFN-gamma. Consistent with these findings we were able to detect by reverse transcription-PCR the expression of mRNA for different chains of IL-4 and IL-13 receptors (IL-4Ralpha, IL-13Ralpha1 and IL-13Ralpha2) but not for IL-10 receptor in the 2C4 and other human lung fibroblast cell lines (LL24 and MRC5). Together our results indicate that IL-4 and IL-13, but not IL-10, are implicated in the negative regulation of IFN-gamma-induced anti-Toxoplasma activity in human cells from fibroblast lineage.