Service de Biochimie et de Biologie Moleculaire

Paris, France

Service de Biochimie et de Biologie Moleculaire

Paris, France
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Rose C.,University of Paris Descartes | Peoc'h K.,Service de Biochimie et de Biologie moleculaire | Peoc'h K.,University of Paris Descartes | Chasseigneaux S.,University of Paris Descartes | And 9 more authors.
BMC Neuroscience | Year: 2012

Background: Amyloid precursor protein (APP), a key molecule in Alzheimer's disease (AD), is metabolized in two alternative cleavages, generating either the amyloidogenic peptides involved in AD pathology or the soluble form of APP (sAPPα). The level of amyloidogenic peptides in human cerebrospinal fluid (CSF) is considered to be a biomarker of AD, whereas the level of sAPPα in CSF as a biomarker has not been clearly established. sAPPα has neurotrophic and neuroprotective properties. Stimulating its formation and secretion is a promising therapeutic target in AD research. To this end, very sensitive tests for preclinical and clinical research are required.Methods: The tests are based on homogenous time-resolved fluorescence and require no washing steps.Results: We describe two new rapid and sensitive tests for quantifying mouse and human sAPPα. These 20 μl-volume tests quantify the levels of: i) endogenous mouse sAPPα in the conditioned medium of mouse neuron primary cultures, as well as in the CSF of wild-type mice, ii) human sAPPα in the CSF of AD mouse models, and iii) human sAPPα in the CSF of AD and non-AD patients. These tests require only 5 μl of conditioned medium from 5 × 104 mouse primary neurons, 1 μl of CSF from wild-type and transgenic mice, and 0.5 μl of human CSF.Conclusions: The high sensitivity of the mouse sAPPα test will allow high-throughput investigations of molecules capable of increasing the secretion of endogenous sAPPα in primary neurons, as well as the in vivo validation of molecules of interest through the quantification of sAPPα in the CSF of treated wild-type mice. Active molecules could then be tested in the AD mouse models by quantifying human sAPPα in the CSF through the progression of the disease. Finally, the human sAPPα test could strengthen the biological diagnosis of AD in large clinical investigations. Taken together, these new tests have a wide field of applications in preclinical and clinical studies. © 2012 Rose et al.; licensee BioMed Central Ltd.


Behlouli A.,University of Science and Technology Houari Boumediene | Behlouli A.,University Alger 1 | Bonnet C.,French Institute of Health and Medical Research | Abdi S.,University Alger 1 | And 11 more authors.
International Journal of Pediatric Otorhinolaryngology | Year: 2016

Congenital deafness is certainly one of the most common monogenic diseases in humans, but it is also one of the most genetically heterogeneous, which makes molecular diagnosis challenging in most cases. Whole-exome sequencing in two out of three Algerian siblings affected by recessively-inherited, moderate to severe sensorineural deafness allowed us to identify a novel splice donor site mutation (c.5272. +. 1G > A) in the gene encoding α-tectorin, a major component of the cochlear tectorial membrane. The mutation was present at the homozygous state in the three affected siblings, and at the heterozygous state in their unaffected, consanguineous parents. To our knowledge, this is the first reported TECTA mutation leading to the DFNB21 form of hearing impairment among Maghrebian individuals suffering from congenital hearing impairment, which further illustrates the diversity of the genes involved in congenital deafness in the Maghreb. © 2016 Elsevier Ireland Ltd.


Collet C.,Service de Biochimie et de Biologie Moleculaire | Legeai-Mallet L.,University of Paris Descartes | Le Merrer M.,University of Paris Descartes | Hadj-Rabia S.,University of Paris Descartes
Child's Nervous System | Year: 2011

Background: Crouzon syndrome with acanthosis nigricans also named Crouzono-dermo-skeletal is a clinically and genetically distinct entity. It associates a craniofacial phenotype to anomalies of the skin and long bones. This syndrome is due to a specific mutation in FGFR3 gene that can be identified by genetic testing. Illustrative cases: As in our two patients, not all these features might be present and some will be patent only in the infancy or early childhood. Moreover, other organs such as the kidneys might be affected. Discussion: Because several organs might be affected the recognition of such syndrome is important for a correct management of the patient as well as a proper information and genetic counseling of the families. © 2010 Springer-Verlag.


Guillot L.,French Institute of Health and Medical Research | Carre A.,University of Paris Descartes | Szinnai G.,University of Basel | Castanet M.,University of Paris Descartes | And 10 more authors.
Human Mutation | Year: 2010

NKX2-1 (NK2 homeobox 1) is a critical regulator of transcription for the surfactant protein (SP)-B and -C genes (SFTPB and SFTPC, respectively). We identified and functionally characterized two new de novo NKX2-1 mutations c.493C>T (p.R165W) and c.786-787del2 (p.L263fs) in infants with closely similar severe interstitial lung disease (ILD), hypotonia, and congenital hypothyroidism. Functional analyses using A549 and HeLa cells revealed that NKX2-1-p.L263fs induced neither SFTPB nor SFTPC promoter activation and had a dominant negative effect on wild-type (WT) NKX2-1. In contrast, NKX2-1-p.R165W activated SFTPC, to a significantly greater extent than did WT NKX2-1, while SFTPB activation was only significantly reduced in HeLa cells. In accordance with our in vitro data, we found decreased amounts of SP-B and SP-C by western blot in bronchoalveolar lavage fluid (patient with p.L263fs) and features of altered surfactant protein metabolism on lung histology (patient with NKX2-1-p.R165W). In conclusion, ILD in patients with NKX2-1 mutations was associated with altered surfactant protein metabolism, and both gain and loss of function of the mutated NKX2-1 genes on surfactant protein promoters were associated with ILD in "Brain-Lung-Thyroid syndrome". © 2009 Wiley-Liss, Inc.


Abermil N.,Service de Genetique | Abermil N.,University of Paris Descartes | Guillaud-Bataille M.,Service de Genetique | Burnichon N.,Service de Genetique | And 20 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2012

Context: TMEM127 is a novel pheochromocytoma (PCC) susceptibility gene. Objectives: Our aim was to clearly determine the indications for TMEM127 genetic testing in patients with PCC and/or paraganglioma (PGL). Patients and Methods: Germline DNAfrom 642 unrelated patients who did not carry mutations in major PCC susceptibility genes was analyzed. Five hundred fifty-nine patients were affected by PCC, 72 by PGL (22 with head and neck and 50 with thoracic or abdominal location), and 11 by both PCC and PGL. Analysis of the TMEM127 gene was performed by direct sequencing and quantitative multiplex PCR of short fluorescent fragments. Results: In our cohort six mutations (0.9%) were identified. Three of them (p.Ala47Asp, p.Gln64HisfsX18, p.Tyr164X) were found in patients exhibiting clinical criteria for a hereditary disease (young age at diagnosis, bilateral PCC, or family history). The three others (p.Gln157X, p.Val68SerfsX13, p.Val90Met) were detected in patients with an apparently sporadic presentation. No mutation was found among patients with PGL, and no large chromosomal rearrangement spanning the TMEM127 gene was detected. Conclusions: Our results combined with the two previous studies suggest that direct sequencing of TMEM127should be considered, after a negative screening of VHL, RET, SDHB, and SDHD genes, in patients with PCC. Copyright © 2012 by The Endocrine Society.


Schaefer E.,Hopitaux Universitaires Of Strasbourg | Schaefer E.,University of Strasbourg | Collet C.,Service de Biochimie et de Biologie Moleculaire | Genevieve D.,Montpellier University | And 11 more authors.
Genetics in Medicine | Year: 2014

Purpose:Treacher Collins syndrome is a mandibulofacial dysostosis caused by mutations in genes involved in ribosome biogenesis and synthesis. TCOF1 mutations are observed in ∼80% of the patients and are inherited in an autosomal dominant manner. Recently, two other genes have been reported in <2% of patients - POLR1D in patients with autosomal dominant inheritance, and POLR1C in patients with autosomal recessive inheritance.Methods:We performed direct sequencing of TCOF1, POLR1C, and POLR1D in two unrelated consanguineous families.Results:The four affected children shared the same homozygous mutation in POLR1D (c.163C>G, p.Leu55Val). This mutation is localized in a region encoding the dimerization domain of the RNA polymerase. It is supposed that this mutation impairs RNA polymerase, resulting in a lower amount of mature dimeric ribosomes. A functional analysis of the transcripts of TCOF1 by real-time quantitative reverse transcription-polymerase chain reaction was performed in the first family, demonstrating a 50% reduction in the index case, compatible with this hypothesis.Conclusion:This is the first report of POLR1D mutation being responsible for an autosomal recessive inherited Treacher Collins syndrome. These results reinforce the concept of genetic heterogeneity of Treacher Collins syndrome and underline the importance of combining clinical expertise and familial molecular analyses for appropriate genetic counseling.Genet Med 16 9, 720-724. © American College of Medical Genetics and Genomics.


Riche F.,Hopital Lariboisiere | Gayat E.,Hopital Lariboisiere | Gayat E.,French Institute of Health and Medical Research | Gayat E.,University Paris Diderot | And 12 more authors.
Critical Care | Year: 2013

Introduction: Our aim was to describe inflammatory cytokines response in the peritoneum and plasma of patients with peritonitis. We also tested the hypothesis that scenarios associated with worse outcome would result in different cytokine release patterns. Therefore, we compared cytokine responses according to the occurrence of septic shock, mortality, type of peritonitis and peritoneal microbiology. Methods: Peritoneal and plasma cytokines (interleukin (IL) 1, tumor necrosis factor α (TNFα), IL-6, IL-10, and interferon γ (IFNγ)) were measured in 66 patients with secondary peritonitis. Results: The concentration ratio between peritoneal fluid and plasma cytokines varied from 5 (2 to 21) (IFNγ) to 1310 (145 to 3888) (IL-1). There was no correlation between plasma and peritoneal fluid concentration of any cytokine. In the plasma, TNFα, IL-6, IFNγ and IL-10 were higher in patients with shock versus no shock and in nonsurvivors versus survivors (P ≤0.03). There was no differential plasma release for any cytokine between community-acquired and postoperative peritonitis. The presence of anaerobes or Enterococcus species in peritoneal fluid was associated with higher plasma TNFα: 50 (37 to 106) versus 38 (29 to 66) and 45 (36 to 87) versus 39 (27 to 67) pg/ml, respectively (P = 0.02). In the peritoneal compartment, occurrence of shock did not result in any difference in peritoneal cytokines. Peritoneal IL-10 was higher in patients who survived (1505 (450 to 3130) versus 102 (9 to 710) pg/ml; P = 0.04). The presence of anaerobes and Enterococcus species was associated with higher peritoneal IFNγ: 2 (1 to 6) versus 10 (5 to 28) and 7 (2 to 39) versus 2 (1 to 6), P = 0.01 and 0.05, respectively). Conclusions: Peritonitis triggers an acute systemic and peritoneal innate immune response with a simultaneous release of pro and anti-inflammatory cytokines. Higher levels of all cytokines were observed in the plasma of patients with the most severe conditions (shock, non-survivors), but this difference was not reflected in their peritoneal fluid. There was always a large gradient in cytokine concentration between peritoneal and plasma compartments highlighting the importance of compartmentalization of innate immune response in peritonitis. © 2013 Riché et al.; licensee BioMed Central Ltd.


PubMed | Service de biochimie et de biologie moleculaire, Blida University, University of Algiers 1, University Pierre and Marie Curie and 3 more.
Type: Journal Article | Journal: PloS one | Year: 2016

Usher syndrome (USH) is an autosomal recessive disorder characterized by a dual sensory impairment affecting hearing and vision. USH is clinically and genetically heterogeneous. Ten different causal genes have been reported. We studied the molecular bases of the disease in 18 unrelated Algerian patients by targeted-exome sequencing, and identified the causal biallelic mutations in all of them: 16 patients carried the mutations at the homozygous state and 2 at the compound heterozygous state. Nine of the 17 different mutations detected in MYO7A (1 of 5 mutations), CDH23 (4 of 7 mutations), PCDH15 (1 mutation), USH1C (1 mutation), USH1G (1 mutation), and USH2A (1 of 2 mutations), had not been previously reported. The deleterious consequences of a missense mutation of CDH23 (p.Asp1501Asn) and the in-frame single codon deletion in USH1G (p.Ala397del) on the corresponding proteins were predicted from the solved 3D-structures of extracellular cadherin (EC) domains of cadherin-23 and the sterile alpha motif (SAM) domain of USH1G/sans, respectively. In addition, we were able to show that the USH1G mutation is likely to affect the binding interface between the SAM domain and USH1C/harmonin. This should spur the use of 3D-structures, not only of isolated protein domains, but also of protein-protein interaction interfaces, to predict the functional impact of mutations detected in the USH genes.


Hajj A.,Saint - Joseph University | Khabbaz L.,Saint - Joseph University | Laplanche J.-L.,Service de Biochimie et de Biologie Moleculaire | Laplanche J.-L.,University of Paris Descartes | And 2 more authors.
Pharmacogenomics | Year: 2013

Opioids are the cornerstone of analgesic therapy and are used as a substitution therapy for opiate addiction. Interindividual variability in response to opioids is a significant challenge in the management of pain and substitution. Therefore, treatment with opioids requires a careful individualization of dosage to achieve an appropriate balance of efficacy and adverse effects and, consequently, avoid toxicity, particularly respiratory depression, sedation and for some, cardiac ventricular fibrillations. Many studies have investigated the association between genetic factors and the variability of response to opioids. Variants in genes encoding proteins implied in opioid pharmacokinetics (absorption, distribution, metabolism, excretion and toxicity), together with those implied in opioids direct and indirect pharmacodynamics (genes of opioid receptors and monoaminergic systems), are the most studied. Many association studies have not been replicated. The purpose of this article is to summarize pharmacogenetic data associated with some opioids frequently encountered in managed care settings. © 2013 Future Medicine Ltd.


Schiltz C.,French Institute of Health and Medical Research | Schiltz C.,University Paris Diderot | Prouillet C.,French Institute of Health and Medical Research | Prouillet C.,University Paris Diderot | And 9 more authors.
Journal of Cellular Physiology | Year: 2010

The Runx2 gene is essential for osteoblast differentiation and function. In vivo over-expression of Runx2 in osteoblasts increases bone resorption, and blocks terminal osteoblast differentiation. Several lines of evidence suggest that osteoblastic matrix metalloproteinases (MMPs) could contribute to the increased bone resorption observed in mice over-expressing Runx2 (Runx2 mice). The goal of our study was to use a transgenic approach to find out whether the inhibition of osteoblastic MMPs can reduce the bone loss induced by the over-expression of Runx2. We analyzed the effect of the in vivo over-expression of the TIMP-1 in osteoblasts on the severe osteopenic phenotype in Runx2 mice. Females with the different genotypes (WT, Runx2, TIMP-1 and TIMP-1/Runx2) were analyzed for bone density, architecture, osteoblastic and osteoclastic activity and gene expression using qPCR. TIMP-1 over-expression reduces the bone loss in adult Runx2 mice. The prevention of the bone loss in TIMP-1/Runx2 mice was due to a combination of reduced bone resorption and sustained bone formation. We present evidence that the ability of osteoblastic cells to induce osteoclastic differentiation is lower in TIMP-1/Runx2 mice than in Runx2 mice, probably due to a reduction in the expression of RANK-L and of the Runx2 transgene. Osteoblast primary cells from TIMP-1/Runx2 mice, but not from Runx2 mice, were able to differentiate into fully mature osteoblasts producing high osteocalcin levels. In conclusion, our findings suggest that osteoblastic MMPs can affect osteoblast differentiation. Our work also indicates that osteoblastic MMPs are partly responsible for the bone loss observed in Runx2 transgenic mice. © 2009 Wiley-Liss, Inc.

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