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At least 1,189 records · Page 66Linked to original sources
PubMed2000

Normal thymic architecture and negative selection are associated with Aire expression, the gene defective in the autoimmune-polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED).

T cell development is tightly controlled by thymic stromal cells. Alterations in stromal architecture affect T cell maturation and the development of self-tolerance. The monogenic autoimmune syndrome APECED (autoimmune-polyendocrinopathy-candidiasis-ectodermal dystrophy) is characterized by the loss of self-tolerance to multiple organs. Although mutations in the autoimmune regulator (AIRE) gene are responsible for this disease, the function of AIRE is not known. Here we report on the spatial and temporal pattern of murine Aire expression during thymic ontogeny and T cell selection. Early during development, thymic Aire transcription is critically dependent on RelB and occurs in epithelial cells in response to lymphocyte-mediated signals. In adult tissue, Aire expression is confined to the medulla and the corticomedullary junction, where it is modulated by thymocytes undergoing negative selection. Aire may determine thymic stromal organization and with it the induction of self-tolerance.

Animals↗
PubMed2007

A defect of regulatory T cells in patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy.

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), a monogenic recessive disease characterized by autoimmunity against multiple tissues, offers a unique possibility to study the breakdown of self-tolerance in humans. It is caused by mutations in the autoimmune regulator gene (AIRE), which encodes a transcriptional regulator. Work using Aire(-/-) mice suggests that Aire induces ectopic expression of peripheral Ags and promotes their presentation in the thymus. We have explored reasons for the difference between the comparatively mild phenotype of Aire-deficient mice and human APECED patients. We provide evidence that, unlike in the Aire(-/-) mice, in the patients a key mediator of active tolerance, the CD4(+)CD25(+) regulatory T (Treg) cell subset is impaired. This was shown by significantly decreased expression of FOXP3 mRNA and protein, decreased function, and alterations in TCR repertoire. Also, in the normal human thymus a concentric accumulation of AIRE(+) cells was seen around thymic Hassall's corpuscles, suggesting that in the patients these cells may be involved in the observed Treg cell failure. In Aire(-/-) mice the expression of FoxP3 was normal and even increased in target tissues in parallel with the lymphocyte infiltration process. Our results suggest that a Treg cell defect is involved in the pathogenesis of APECED and emphasize the importance of active tolerance mechanisms in preventing human autoimmunity.

Adult↗
PubMed2001

Up-regulation of the ectodermal-neural cortex 1 (ENC1) gene, a downstream target of the beta-catenin/T-cell factor complex, in colorectal carcinomas.

To clarify the molecular mechanisms of human carcinogenesis associated with abnormal Wnt/wingless signaling, we searched for genes the expression of which was significantly altered by introduction of wild-type AXIN1 into LoVo colon cancer cells. By means of a cDNA microarray, we compared expression profiles of LoVo cells infected with either adenoviruses expressing wild-type AXIN1 (Ad-Axin) or those expressing a control gene (Ad-LacZ). Among the genes showing altered expression, the ectodermal-neural cortex 1 (ENC1) gene was down-regulated in response to Ad-Axin. The promoter activity of ENC1 was elevated approximately 3-fold by transfection of an activated form of beta-catenin together with wild-type T-cell factor (Tcf)4 in HeLa cells. Semiquantitative reverse transcription-PCR experiments revealed that expression of ENC1 was increased in more than two-thirds of 24 primary colon cancer tissues that we examined compared with corresponding noncancerous mucosae. Introduction of exogenous ENC1 increased the growth rate of HCT116 colon cancer cells in serum-depleted medium. In other experiments, overexpression of ENC1 in HT-29 colon cancer cells suppressed the usual increase of two differentiation markers, in response to treatment with sodium butyrate, a differentiation-inducible agent. These data suggest that ENC1 is regulated by the beta-catenin/Tcf pathway and that its altered expression may contribute to colorectal carcinogenesis by suppressing differentiation of colonic cells.

Axin Protein↗
PubMed2004

Filippi syndrome: two cases with ectodermal features, expanding the phenotype.

We report two unrelated children with Filippi syndrome. Both show typical facial dysmorphism, syndactyly of fingers and toes, growth retardation, postnatal microcephaly and developmental delay, particularly involving speech. In addition both children have unusual teeth and hair. We review the literature and propose that neurological and ectodermal involvement may be under-recognised features of the syndrome.

Adolescent↗
PubMed1990

[Juvenile periodontopathies as a manifestation of an ectodermal abnormality].

By means of three cases of progressive infantile periodontal diseases the author points at simultaneous alteration in the keratinization of the skin in the sense of keratosis palmaris et plantaris (Papillon-Lefèvre-Disease). This complex of anomalies is supposed to be a hereditary acro-ectodermal systemic inferiority, primarily consisting in an epithelial disturbance. But it is also necessary to regard the infantile progressive periodontal insufficiency as an obligatory or facultative attendant symptom of general diseases. The therapy is only symptomatic, complete return to health is not realizable.

Aggressive Periodontitis↗
PubMed1981

Evaluation of ectodermal lesions in intravenous vaccinia infected mice as a method to investigate the antiviral activity of isatin beta-thiosemicarbazone derivative (TSK VI compound).

In this paper ectodermal lesions on the tails of mice inoculated intravenously with vaccinia virus were used to study the influence of N,N'-bis[methylisatin-beta-thiosemicarbazone]-2-methylpiperazine (TSKI VI) on the number and dynamics of lesion formations. The activity of this compound was compared to that of the antiviral drug, methisazone. The reduction in lesions after treatment with TSKI VI was similar to the reduction induced by methisazone, which, on the basis of earlier theroretical and experimental data as well as on the lower toxicity of TSKI VI for the tissues and a more favorable therapeutic index, makes this compound worth considering in the treatment of postvaccinal complications. This method proved very useful in examination of the substances having potential prophylactic properties in preventing generalized infections.

Animals↗
PubMed1993

Intracerebral primitive neuro-ectodermal tumor (PNET).

A case of intracerebral primitive neuro-ectodermal tumor (PNET) is presented. PNETs are rare, undifferentiated neoplasms occurring primarily in children and young adults. These tumors exhibit a highly malignant behaviour with a tendency to disseminate along the cerebrospinal fluid (CSF) pathways. Preoperative diagnosis is difficult, owing to the non-specific CT and MR appearances and to the rarity of this tumor. Our patient was 33 years old, which is uncommon. CT findings initially suggested an intracerebral hematoma. Later on, CT and MR findings were specific for a brain tumor and showed a solid, non-calcified invasive mass, with poor perilesional edema.

Adult↗
PubMed1997

[A rare case of juvenile diabetes mellitus associated with APECED (autoimmune poly-endocrinopathy, candidiasis and ectodermal dystrophy) with strong X-linked familial inheritance].

The polyglandular autoimmune syndromes (PGA) are well known and are distinguished into type I, type II and type III. PGAI, also called APECED (autoimmune polyendocrinopathy, candidiasis and ectodermal dystrophy), is an autosomal recessive disorder, appearing in childhood and typically characterized by hypoparathyroidism (unusual in PGAII and PGAIII) and adrenal insufficiency. In APECED, autoimmune destruction of the pancreatic beta cells with development of insulin-dependent type 1 diabetes is possible, but less frequent than in the other PGAs, especially PGAII. The pathogenesis of this unique autoimmune disease is unknown. No HLA association seems to exist and genetic studies have assigned the autosomal APECED locus to chromosome 21. The case of a 28-years-old female suggesting the diagnosis of APECED, is presented, characterized by psycho-somatic abnormal development, teeth alterations, post-puberal gonadal failure with dystrophic hypoplasia of external genitalia, previous vaginal candidiasis, a slowly developing juvenile brittle diabetes. Intestinal malabsorption induced by Giardia lamblia occurred (probably resulting, like candidiasis, from immunological anergy). A strong familiarity linked to female sex was noticed (the mother, a sister, the little nice and some maternal female cousins being affected) while the father and a brother were healthy. Diabetes seems to be characterized by early onset and severe complications. In this patient no organo-specific antibodies were detected and the only immunologic disorder was a small decrease of CD3 and CD4/CD8 ratio, both CD4 and CD8 being at the lower normal range. This patient (and her female maternal relatives) needs a long-term follow-up in order to evaluate the function of endocrine glands and to initiate early treatment for hormonal deficits, as well as to detect the non-endocrine components of disease.

Adult↗