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Afonso P.,French Institute of Health and Medical Research | Afonso P.,Paris-Sorbonne University | Afonso P.,Institute of Cardiometabolism and Nutrition | Auclair M.,French Institute of Health and Medical Research | And 17 more authors.
Atherosclerosis | Year: 2016

Background: Some LMNA mutations responsible for lipodystrophies, and some HIV-protease inhibitors (PIs) induce accumulation of farnesylated prelamin A and premature senescence in some cell types. Patients with LMNA mutations or under PI-based therapy suffer from early atherosclerosis. The metalloprotease ZMPSTE24 is the key enzyme in prelamin A maturation. Aim: We studied whether altered expression of ZMPSTE24 could contribute to vascular cell dysfunction in response to LMNA mutations or PI treatments. Methods: Protein expression of prelamin A and ZMPSTE24 were evaluated in patients' cells and in human cultured VSMCs. Oxidative stress, inflammation, senescence and transdifferentiation/calcification were evaluated in VSMCs. Results: Fibroblasts from LMNA-mutated lipodystrophic patients (mutations R482W, D47Y or R133L) and peripheral blood mononuclear cells from PI-treated-HIV-infected patients expressed increased prelamin A and decreased ZMPSTE24, which was also observed in VSMCs overexpressing mutant LMNA or treated with PIs. These alterations correlated with oxidative stress, inflammation, senescence and calcification (all p < 0.05). ZMPSTE24 silencing in native VSMCs recapitulated the mutant LMNA- and PI-induced accumulation of farnesylated prelamin A, oxidative stress, inflammation, senescence and calcification. A negative regulator of ZMPSTE24, miRNA-141-3p, was enhanced in LMNA-mutated or PI-treated VSMCs. The farnesylation inhibitors pravastatin and FTI-277, or the antioxidant N-acetyl cysteine, partly restored ZMPSTE24 expression, and concomitantly decreased oxidative stress, inflammation, senescence, and calcification of PI-treated VSCMs. Conclusions: ZMPSTE24 downregulation is a major contributor in VSMC dysfunctions resulting from LMNA mutations or PI treatments that could translate in early atherosclerosis at the clinical level. These novel pathophysiological mechanisms could open new therapeutic perspectives for cardiovascular aging. © 2015 Elsevier Ireland Ltd.


Thauvin-Robinet C.,University of Burgundy | Auclair M.,Institute National Of La Sante Et Of La Recherche Medicale Unite Mixte Of Recherche S938 | Auclair M.,University Pierre and Marie Curie | Auclair M.,Institut Universitaire de France | And 36 more authors.
American Journal of Human Genetics | Year: 2013

Short stature, hyperextensibility of joints and/or inguinal hernia, ocular depression, Rieger anomaly, and teething delay (SHORT) syndrome is a developmental disorder with an unknown genetic cause and hallmarks that include insulin resistance and lack of subcutaneous fat. We ascertained two unrelated individuals with SHORT syndrome, hypothesized that the observed phenotype was most likely due to de novo mutations in the same gene, and performed whole-exome sequencing in the two probands and their unaffected parents. We then confirmed our initial observations in four other subjects with SHORT syndrome from three families, as well as 14 unrelated subjects presenting with syndromic insulin resistance and/or generalized lipoatrophy associated with dysmorphic features and growth retardation. Overall, we identified in nine affected individuals from eight families de novo or inherited PIK3R1 mutations, including a mutational hotspot (c.1945C>T [p.Arg649Trp]) present in four families. PIK3R1 encodes the p85α, p55α, and p50α regulatory subunits of class IA phosphatidylinositol 3 kinases (PI3Ks), which are known to play a key role in insulin signaling. Functional data from fibroblasts derived from individuals with PIK3R1 mutations showed severe insulin resistance for both proximal and distal PI3K-dependent signaling. Our findings extend the genetic causes of severe insulin-resistance syndromes and provide important information with respect to the function of PIK3R1 in normal development and its role in human diseases, including growth delay, Rieger anomaly and other ocular affections, insulin resistance, diabetes, paucity of fat, and ovarian cysts. © 2013 The American Society of Human Genetics.


Castell A.L.,Nice University Hospital Center | Hieronimus S.,Nice University Hospital Center | Lascols O.,Laboratoire Communications Of Biologie Et Genetique Moleculaires | Fournier T.,French Institute of Health and Medical Research | Fenichel P.,Nice University Hospital Center
Diabetes and Metabolism | Year: 2012

The peroxisome proliferator-activated receptor protein gamma (PPARγ), a nuclear receptor involved in adipocyte differentiation, energy homoeostasis and fat storage, can lead, in rare cases of coding mutations, to familial partial lipodystrophy type 3 (FPLD3) with severe insulin resistance. PPARγ is also highly expressed in the syncytiotrophoblast and extravillous cytotrophoblast cells. It has a key role in trophoblast invasion, as shown by studies in vitro, but its precise role during placentation remains to be elucidated, and fetomaternal outcomes of FPLD3 pregnancies also need to be assessed. This report is of a novel missense heterozygous mutation of PPARγ identified during pregnancy in a young diabetic woman who, at 3. weeks of amenorrhoea, prematurely delivered a baby who died 24. h later. Histopathological analysis revealed important vascular placental abnormalities. The presence of the PPARγ mutation in placental tissues in the absence of fetal malformations and maternal hypertension suggests that FPLP3 pregnancies may be at high-risk, especially if the fetus has inherited the mutation. It also supports a physiological role for PPARγ during placentation. © 2012 Elsevier Masson SAS.


Vadrot N.,University Paris Diderot | Duband-Goulet I.,University Paris Diderot | Cabet E.,University Paris Diderot | Attanda W.,University Paris Diderot | And 15 more authors.
Human Molecular Genetics | Year: 2014

Nuclear lamins are involved in many cellular functions due to their ability to bind numerous partners including chromatin and transcription factors, and affect their properties. Dunnigan type familial partial lipodystrophy (FPLD2; OMIM#151660) is caused in most cases by the A-type lamin R482W mutation.We report here that the R482W mutation affects the regulatory activity of sterol response element binding protein 1 (SREBP1), a transcription factor that regulates hundreds of genes involved in lipid metabolism and adipocyte differentiation. Using in situ proximity ligation assays (PLA), reporter assays and biochemical and transcriptomic approaches,we showthat interactions of SREBP1 with lamin A and lamin Coccur at the nuclear periphery and in the nucleoplasm. These interactions involve the Ig-fold of A-type lamins and are favored upon SREBP1 binding to its DNA target sequences. We show that SREBP1, LMNA and sterol response DNA elements form ternary complexes in vitro. In addition, overexpression of A-type lamins reduces transcriptional activity of SREBP1. In contrast, both overexpression of LMNA R482W in primary human preadipocytes and endogenous expression of A-type lamins R482W in FPLD2 patient fibroblasts, reduce A-type lamins-SREBP1 in situ interactions and upregulate a large number of SREBP1 target genes. As this LMNA mutant was previously shown to inhibit adipogenic differentiation, we propose that deregulation of SREBP1 by mutated A-type lamins constitutes one underlying mechanism of the physiopathology of FPLD2. Our data suggest that SREBP1 targeting molecules could be considered in a therapeutic context. © The Author 2014.


Le Dour C.,Institute National Of La Sante Et Of La Recherche Medicale Unite Mixte Of Recherche Umr S938 | Le Dour C.,University Pierre and Marie Curie | Schneebeli S.,Groupe Hospitalier Sud Reunion | Bakiri F.,Center Hospitalier Felix Guyon | And 15 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2011

Context: Mutations in LMNA, encoding A-type lamins, lead to multiple laminopathies, including lipodystrophies, progeroid syndromes, and cardiomyopathies. Alterations in the prelamin-A posttranslational maturation, resulting in accumulation of farnesylated isoforms, cause human progeroid syndromes. Accumulation of mutant nonfarnesylated prelamin-A leads to cardiomyopathy or progeria in mice, but no data have been provided in humans. Objective, Design, Setting, and Patients: We searched for LMNA mutations in seven women originating from Reunion Island who were referred for a severe lipodystrophic syndrome. Clinical, molecular, genealogical, and cellular studies were performed in probands and relatives. Results: The seven probands showed a severe partial lipodystrophic syndrome with diabetes and/or acanthosis nigricans, liver steatosis, hypertriglyceridemia, and low serum leptin and adiponectin levels. Three probands also had severe cardiac rhythm and conduction disturbances. We identified in all probands a homozygousLMNAp.T655fsX49 mutation leading to expression of a mutated prelamin-A with 48 aberrant C-terminal amino acids, preventing its physiological posttranslational farnesylation and maturation. Genealogical and haplotype analyses were consistent with a founder mutation transmitted from a common ancestor in the 17th century. In probands' cultured fibroblasts, mutated prelamin-A was associated with typical laminopathic nuclear dysmorphies, increased oxidative stress, and premature senescence. Heterozygous relatives were asymptomatic or partially affected, in favor of a codominant transmission of the disease with incomplete penetrance in heterozygotes. Conclusions: We reveal that a homozygous mutation of prelamin-A preventing its farnesylation leads to a severe lipodystrophic laminopathy in humans, which can be associated with cardiac conduction disturbances, stressing the pathogenicity of nonfarnesylated prelamin-A in human laminopathies. Copyright © 2011 by The Endocrine Society.


Auclair M.,French Institute of Health and Medical Research | Auclair M.,University Pierre and Marie Curie | Auclair M.,Institute of Cardiometabolism and Nutrition | Vigouroux C.,French Institute of Health and Medical Research | And 20 more authors.
Arteriosclerosis, Thrombosis, and Vascular Biology | Year: 2013

OBJECTIVE: Inactivating peroxisome proliferator-activated receptor-γ (PPARγ) mutations lead to a syndrome of familial partial lipodystrophy (FPLD3) associated with early-onset severe hypertension. PPARγ can repress the vascular renin-angiotensin system (RAS) and angiotensin II receptor 1 expression. We evaluated the relationships between PPARγ inactivation and cellular RAS using FPLD3 patients' cells and human vascular smooth muscle cells expressing mutant or wild-type PPARγ. APPROACH AND RESULTS: We identified 2 novel PPARG mutations, R165T and L339X, located in the DNA and ligand-binding domains of PPARγ, respectively in 4 patients from 2 FPLD3 families. In cultured skin fibroblasts and peripheral blood mononuclear cells from the 4 patients and healthy controls, we compared markers of RAS activation, oxidative stress, and inflammation, and tested the effect of modulators of PPARγ and angiotensin II receptor 1. We studied the impact of the 2 mutations on the transcriptional activity of PPARγ and on the vascular RAS in transfected human vascular smooth muscle cells. Systemic RAS was not altered in patients. However, RAS markers were overexpressed in patients' fibroblasts and peripheral blood mononuclear cells, as in vascular cells expressing mutant PPARγ. Angiotensin II-mediated mitogen-activated protein kinase activity increased in patients' fibroblasts, consistent with RAS constitutive activation. Patients' cells also displayed oxidative stress and inflammation. PPARγ activation and angiotensin II receptor 1 mRNA silencing reversed RAS overactivation, oxidative stress, and inflammation, arguing for a role of angiotensin II receptor 1 in these processes. CONCLUSIONS: Two novel FPLD3-linked PPARG mutations are associated with a defective transrepression of cellular RAS leading to cellular dysfunction, which might contribute to the specific FPLD3-linked severe hypertension. © 2013 American Heart Association, Inc.


Gandotra S.,University of Cambridge | Le Dour C.,University Pierre and Marie Curie | Bottomley W.,Wellcome Trust Sanger Institute | Cervera P.,University Pierre and Marie Curie | And 17 more authors.
New England Journal of Medicine | Year: 2011

Perilipin is the most abundant adipocyte-specific protein that coats lipid droplets, and it is required for optimal lipid incorporation and release from the droplet. We identified two heterozygous frameshift mutations in the perilipin gene (PLIN1) in three families with partial lipodystrophy, severe dyslipidemia, and insulin-resistant diabetes. Subcutaneous fat from the patients was characterized by smaller-than-normal adipocytes, macrophage infiltration, and fibrosis. In contrast to wild-type perilipin, mutant forms of the protein failed to increase triglyceride accumulation when expressed heterologously in preadipocytes. These findings define a novel dominant form of inherited lipodystrophy and highlight the serious metabolic consequences of a primary defect in the formation of lipid droplets in adipose tissue. Copyright © 2011 Massachusetts Medical Society.


Hirsch P.,Hopital Saint Antoine | Hirsch P.,University Pierre and Marie Curie | Tang R.,Hopital Saint Antoine | Tang R.,University Pierre and Marie Curie | And 10 more authors.
Haematologica | Year: 2012

ATP-binding cassette transporter (and specially P-glycopro-tein) activity is a well known prognostic factor in acute myeloid leukemia, but when compared to other molecular markers its prognostic value has not been well studied. Here we study relationships between this activity, fms-like tyrosine kinase 3(FLT3/ITD), nucleophosmin(NPM1), CAAT-enhancer binding protein alpha(CEBPα), and brain and acute leukemia cytoplasmic protein (BAALC), in 111 patients with normal cytogenetics who underwent the same treatment, and evaluate its prognostic impact. Independent factors for survival were age (P=0.0126), ATP-binding cassette transporter activity (P=0.018) and duplications in the fms-like tyrosine kinase 3 (P=0.0273). In the 66 patients without fms-like tyrosine kinase 3 duplication and without nucleophosmin mutation, independent prognostic factors for complete remission achievement and survival were age and ATP-binding cassette transporter activity. In conclusion, ATP-binding cassette transporter activity remains an independent prognostic factor, and could assist treatment decisions in patients with no nucleophosmin mutation and no fms-like tyrosine kinase 3 duplication. © 2012 Ferrata Storti Foundation.


Louis M.,Assistance Publique Hopitaux de Paris | Guitard J.,Assistance Publique Hopitaux de Paris | Guitard J.,French Institute of Health and Medical Research | Guitard J.,French National Center for Scientific Research | And 9 more authors.
Journal of Clinical Microbiology | Year: 2015

Quantitative PCR (qPCR) is now a key diagnostic tool for Pneumocystis pneumonia. However, cutoffs to distinguish between infected and colonized patients according to their HIV status have not yet been determined. According to clinical, radiological, and biological data, we retrospectively classified bronchoalveolar lavage (BAL) samples subjected to qPCR over a 3-year period into four categories, i.e., definite PCP, probable PCP, Pneumocystis colonization, and no infection. Fungal burden was then analyzed according to the HIV status of the patients. Among 1,212 episodes of pneumonia screened in immunocompromised patients, 52 and 27 HIV-positive patients were diagnosed with a definite and probable PCP, whereas 4 and 22 HIV-negative patients had definite and probable PCP, respectively. Among patients with definite or a probable PCP, HIV-negative patients had a significantly lower burden than HIV-positive patients (P<10-4). In both groups, the median fungal burden was significantly higher in patients with definite PCP than in colonized patients. A single cutoff at 1.5×104 copies/ml allowed to differentiate colonized and infected HIV-positive patients with 100% sensitivity and specificity. In HIV-negative patients, cutoff values of 2.87×104 and 3.39×103 copies/ml resulted in 100% specificity and sensitivity, respectively. Using cutoffs determined for the whole population would have led us to set aside the diagnosis of PCP in 9 HIV-negative patients with definite or probable PCP. qPCR appeared to be the most sensitive test to detect Pneumocystis in BAL samples. However, because of lower inocula in HIVnegative patients, different cutoffs must be used according to the HIV status to differentiate between colonized and infected patients. © 2015, American Society for Microbiology.


PubMed | Laboratoire Communications Of Biologie Et Genetique Moleculaires, French National Center for Scientific Research and Assistance Publique Hopitaux de Paris
Type: Journal Article | Journal: Journal of clinical microbiology | Year: 2015

Quantitative PCR (qPCR) is now a key diagnostic tool for Pneumocystis pneumonia. However, cutoffs to distinguish between infected and colonized patients according to their HIV status have not yet been determined. According to clinical, radiological, and biological data, we retrospectively classified bronchoalveolar lavage (BAL) samples subjected to qPCR over a 3-year period into four categories, i.e., definite PCP, probable PCP, Pneumocystis colonization, and no infection. Fungal burden was then analyzed according to the HIV status of the patients. Among 1,212 episodes of pneumonia screened in immunocompromised patients, 52 and 27 HIV-positive patients were diagnosed with a definite and probable PCP, whereas 4 and 22 HIV-negative patients had definite and probable PCP, respectively. Among patients with definite or a probable PCP, HIV-negative patients had a significantly lower burden than HIV-positive patients (P < 10(-4)). In both groups, the median fungal burden was significantly higher in patients with definite PCP than in colonized patients. A single cutoff at 1.5 10(4) copies/ml allowed to differentiate colonized and infected HIV-positive patients with 100% sensitivity and specificity. In HIV-negative patients, cutoff values of 2.87 10(4) and 3.39 10(3) copies/ml resulted in 100% specificity and sensitivity, respectively. Using cutoffs determined for the whole population would have led us to set aside the diagnosis of PCP in 9 HIV-negative patients with definite or probable PCP. qPCR appeared to be the most sensitive test to detect Pneumocystis in BAL samples. However, because of lower inocula in HIV-negative patients, different cutoffs must be used according to the HIV status to differentiate between colonized and infected patients.

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