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Nathalie Chabbert-Buffet

Publications and source records attributed to Nathalie Chabbert-Buffet.

8 recordsLinked to original sources
PubMed2006

Ligand-controlled interaction of histone acetyltransferase binding to ORC-1 (HBO1) with the N-terminal transactivating domain of progesterone receptor induces steroid receptor coactivator 1-dependent coactivation of transcription.

Modulators of cofactor recruitment by nuclear receptors are expected to play an important role in the coordination of hormone-induced transactivation processes. To identify such factors interacting with the N-terminal domain (NTD) of the progesterone receptor (PR), we used this domain as bait in the yeast Sos-Ras two-hybrid system. cDNAs encoding the C-terminal MYST (MOZ-Ybf2/Sas3-Sas2-Tip60 acetyltransferases) domain of HBO1 [histone acetyltransferase binding to the origin recognition complex (ORC) 1 subunit], a member of the MYST acetylase family, were thus selected from a human testis cDNA library. In transiently transfected CV1 cells, the wild-type HBO1 [611 amino acids (aa)] enhanced transcription mediated by steroid receptors, notably PR, mineralocorticoid receptor, and glucocorticoid receptor, and strongly induced PR and estrogen receptor coactivation by steroid receptor coactivator 1a (SRC-1a). As assessed by two-hybrid and glutathione-S-transferase pull-down assays, the HBO1 MYST acetylase domain (aa 340-611) interacts mainly with the NTD, and also contacts the DNA-binding domain and the hinge domains of hormone-bound PR. The HBO1 N-terminal region (aa 1-340) associates additionally with PR ligand-binding domain (LBD). HBO1 was found also to interact through its NTD with SRC-1a in the absence of steroid receptor. The latter coassociation enhanced specifically activation function 2 activation function encompassed in the LBD. Conversely, the MYST acetylase domain specifically enhanced SRC-1 coupling with PR NTD, through a hormone-dependent mechanism. In human embryonic kidney 293 cells expressing human PRA or PRB, HBO1 raised selectively an SRC-1-dependent response of PRB but failed to regulate PRA activity. We show that HBO1 acts through modification of an LBD-controlled structure present in the N terminus of PRB leading to the modulation of SRC-1 functional coupling with activation function 3-mediated transcription. Importantly, real-time RT-PCR analysis also revealed that HBO1 enhanced SRC-1 coactivation of PR-dependent transcription of human endogenous genes such as alpha-6 integrin and 11beta-hydroxydehydrogenase 2 but not that of amphiregulin. Immunofluorescence and confocal microscopy of human embryonic kidney-PRB cells demonstrated that the hormone induces the colocalization of HBO1 with PR-SRC-1 complex into nuclear speckles characteristic of PR-mediated chromatin remodeling. Our results suggest that HBO1 might play an important physiological role in human PR signaling.

Animals↗
PubMed2005

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome with renal failure: impact of posttransplant immunosuppression on disease activity.

CONTEXT: Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) is a rare autosomal recessive disorder caused by mutations in the gene AIRE (autoimmune regulator). APECED affects mainly endocrine organs resulting in hypoparathyroidism, adrenocortical failure, diabetes mellitus, hypogonadism, and hypothyroidism. Nonendocrine organ manifestations are autoimmune hepatitis, vitiligo, pernicious anemia, exocrine pancreatic insufficiency, and alopecia. APECED's first manifestation generally is mucocutaneous candidiasis presumably related to T cell dysfunction. PATIENT: A 5-yr-old Iranian girl presented first with pernicious anemia, exocrine pancreatic insufficiency, and nail candidiasis. She had renal dysfunction due to chronic interstitial nephritis (CIN), which progressed to end-stage renal failure. She was transplanted 1 yr later. Common causes of CIN were excluded. APECED was suspected first because she developed progressively hypoparathyroidism, adrenocortical failure, glucose intolerance, and hypothyroidism. RESULTS: Genetic analysis revealed a large homozygous deletion (g.424_2157del1734), spanning exons 2-4, in the AIRE gene. The predicted protein, if it is produced, has only 44 amino acids (exon 1) in common with the wild-type protein. Immunosuppression after the first renal transplant included prednisone, azathioprine, and cyclosporine A. Multiple acute rejection episodes occurred. Chronic rejection resulted in lost graft and she was retransplanted 2 yr later. Surprisingly, all APECED-related symptoms including candidiasis and autoantibody levels decreased, presumably due to the reinforced immunosuppression (tacrolimus, mycophenolate mofetil, prednisone). CONCLUSIONS: This is the first report of an APECED patient with CIN resulting in end-stage renal failure. Clinical and biological improvement was observed under posttransplant multidrug immunosuppression including tacrolimus and mycophenolate mofetil.

Anti-Inflammatory Agents↗
PubMed2005

Selective progesterone receptor modulators and progesterone antagonists: mechanisms of action and clinical applications.

Since the discovery of the antiprogestin mifepristone, hundreds of similar compounds have been synthesized, which can be grouped in a large family of progesterone receptor ligands. This family includes pure agonists such as progesterone itself or progestins and, at the other end of the biological spectrum, pure progesterone receptor antagonists (PA). Selective progesterone receptor modulators (SPRM) have mixed agonist-antagonist properties, and occupy an intermediate position of the spectrum. These compounds have numerous applications in female health care. Mifepristone is used to terminate pregnancy, and as such is commercially available in many countries. The negative abortion-related image of mifepristone has clearly limited the involvement of the major pharmaceutical companies in the development of PA and SPRM. Many PA and SPRM display direct antiproliferative effects in the endometrium, although with variable actions which seem product- and dose-dependent. This property justifies their use in the treatment of myomas and endometriosis. PA also suppress late follicular development, block the LH surge and retard endometrial maturation, which renders them potential estrogen-free contraceptive drugs. SPRM such as asoprisnil are not as effective in blocking the LH surge and appear to target the endometrium directly and produce amenorrhoea. Interestingly, clinical data show that treatment with these compounds is not associated with hypo-estrogenism and bone loss. The potential clinical applications of these compounds cover a broad field and are very promising in major public health areas. These include emergency contraception, long-term estrogen-free contraception (administered alone, or in association with a progestin-only pill to improve bleeding patterns), myomas (where they induce a marked reduction in tumour volume and produce amenorrhoea) and endometriosis. Further developments might also include hormone replacement therapy in post-menopausal women, as well as the treatment of hormone-dependent tumours.

Endometriosis↗
PubMed2005

[Monitoring of postmenopausal women].

Postmenopausal age women have an increased risk of cardiovascular diseases, osteoporosis, and gynaecological cancers. A regular follow up is necessary to evaluate the interest of HRT, and for screening cardiovascular diseases and gynaecologic cancers. Patient counselling includes life style modifications, follow-up and regular evaluation of risk factors and potential benefit of HRT for each woman.

Aged↗
PubMed2005

Management of patients receiving long-term treatment with mifepristone.

OBJECTIVE: To determine clinical side effects and biochemical and hematological abnormalities in patients with nonresectable meningioma on long-term mifepristone (RU 486) therapy. DESIGN: Long-term mifepristone administration in patients with meningioma. SETTING: Outpatient clinic of a university hospital. PATIENT(S): Sixteen women and 9 men aged 22-80 years with nonresectable meningioma. INTERVENTION(S): Mifepristone (200 mg daily). One patient received treatment for more than 13 years; six received treatment for 10-12 years; five received treatment for 4-9 years; eight received treatment for 1-4 years; and the remainder received treatment for 4-10 months. MAIN OUTCOME MEASURE(S): Evaluation of side effects and of hematological and biochemical abnormalities. RESULT(S): Fatigue was observed in 22 of 25 patients. Endometrial hyperplasia occurred in one premenopausal woman and one postmenopausal woman. Another two women had endometrial thickening without hyperplasia. There were no consistent abnormalities in liver or renal function or in any other biochemical or hematological parameters. One subject (on long-term dexamethasone) developed hypoadrenalism, which responded to treatment. CONCLUSION(S): Mifepristone can be administered for prolonged periods. Ultrasound should be performed if irregular vaginal bleeding occurs. In asymptomatic women, it should be performed annually. If endometrial thickening is observed, then endometrial biopsy is recommended. Because biochemical hypothyroidism has been reported during long-term mifepristone therapy, thyroid function tests should be performed annually.

Adrenal Insufficiency↗
PubMed2003

French multicentric survey of outcome of pregnancy in women with pregestational diabetes.

OBJECTIVE: To evaluate perinatal outcome in pregnancies in women with type 1 and type 2 diabetes and the influence of preconception care 10 years after the St. Vincent's declaration. RESEARCH DESIGN AND METHODS: A cross-sectional study was conducted in 12 perinatal centers in France in 2000-2001. The main investigated outcomes were perinatal mortality, major congenital malformations, and preterm delivery. RESULTS: Among 435 single pregnancies, 289 (66.4%) were from women with type 1 and 146 (33.6%) from women with type 2 diabetes. Perinatal mortality rate was 4.4% (0.7% national rate), severe congenital malformations rate was 4.1% (2.2% national rate), and preterm delivery rate was 38.2% (4.7% national rate). Preconception care was provided in 48.5% women with type 1 diabetes and in 24.0% women with type 2 diabetes. Women whose first trimester HbA(1c) was >8% had higher rates of perinatal mortality (9.2 vs. 2.5%; odds ratio 3.9; 95% CI 1.5-9.7; P < 0.005), major congenital malformations (8.3 vs. 2.5%; 3.5; 1.3-8.9; P < 0.01), and preterm delivery (57.6 vs. 24.8%; 1.4; 1.1-1.7; P < 0.005) than those with first trimester HbA(1c) <8%. These results are similar to those reported in France in 1986-1988. CONCLUSIONS: Pregnancies in women with diabetes are still poorly planned and complicated by higher rates of perinatal mortality and major congenital malformations. Despite knowledge of the importance of intensified glycemic control before pregnancy, reaching the St. Vincent's target needs further implementation in France.

Cross-Sectional Studies↗