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Agnès Perrin

Publications and source records attributed to Agnès Perrin.

5 recordsLinked to original sources
PubMed2005

Differential responses of PPARalpha, PPARdelta, and PPARgamma reporter cell lines to selective PPAR synthetic ligands.

To characterize the specificity of synthetic compounds for peroxisome proliferator-activated receptors (PPARs), three stable cell lines expressing the ligand binding domain (LBD) of human PPARalpha, PPARdelta, or PPARgamma fused to the yeast GAL4 DNA binding domain (DBD) were developed. These reporter cell lines were generated by a two-step transfection procedure. First, a stable cell line, HG5LN, expressing the reporter gene was developed. These cells were then transfected with the different receptor genes. With the help of the three PPAR reporter cell lines, we assessed the selectivity and activity of PPAR agonists GW7647, WY-14-643, L-165041, GW501516, BRL49653, ciglitazone, and pioglitazone. GW7647, L-165041, and BRL49653 were the most potent and selective agonists for hPPARalpha, hPPARdelta, and hPPARgamma, respectively. Two PPAR antagonists, GW9662 and BADGE, were also tested. GW9662 was a selective PPARgamma antagonist, whereas BADGE was a low-affinity PPAR ligand. Furthermore, GW9662 was a full antagonist on PPARgamma and PPARdelta, whereas it showed partial agonism on PPARalpha. We conclude that our stable models allow specific and sensitive measurement of PPAR ligand activities and are a high-throughput, cell-based screening tool for identifying and characterizing PPAR ligands.

Anilides↗
PubMed2004

Evidence for transcriptional and posttranscriptional alterations of the sodium/iodide symporter expression in hypofunctioning benign and malignant thyroid tumors.

The uptake of iodide by epithelial thyroid cells requires the expression of a specific transporter, the Na(+)/I(-) symporter, NIS. Benign and malignant thyroid tumors of epithelial origin show a decrease up to a loss of iodide uptake activity. Previous studies of the human NIS (hNIS) gene expression in these tumors, based on the amplification of transcripts and/or immunohistochemical detection of the protein, have yielded divergent data; hNIS expression was found either increased or decreased. To get a new and integrated view of the alterations of hNIS expression in hypofunctioning thyroid tumors, we performed investigations of hNIS transcript and hNIS protein levels on the same tumors and paired normal tissue samples. HNIS, identified as a 75- to 80-kd species, was present in all normal tissue samples from euthyroid patients, but was undetectable, even at high membrane protein input, in all benign and malignant hypofunctioning thyroid tumors. By contrast, approximately 50% of tumors contained hNIS transcripts. This dissociation between transcript and protein levels was not found for the transcript and protein encoded by the PDS gene assayed in the same tumors. The hNIS transcript-positive tumors contained small amounts of low-molecular mass hNIS-immunoreactive species identified as nonglycosylated hNIS. Tumors containing the nonmature form of hNIS exhibited a predominant intracellular immunolabeling. In conclusion, our data show that benign and malignant hypofunctioning thyroid tumors either no longer express hNIS protein or express only a very low amount of nonglycosylated hNIS and indicate that the impairment of hNIS gene expression might result from alterations at both transcriptional and posttranscriptional levels.

Blotting, Western↗
PubMed2003

A combined oligonucleotide and protein microarray for the codetection of nucleic acids and antibodies associated with human immunodeficiency virus, hepatitis B virus, and hepatitis C virus infections.

A multiplexed assay based on the codetection of nucleic acids and antibodies in human serum infected by human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus was proposed. The combined immuno- and oligosorbent array (CombOLISA) microarray is prepared in 96-well standard microplates by spotting (1). nucleic probes specific for a virus genome, (2). viral proteins for the capture of serum antibodies, and (3). nonspecific proteins for verifying specificity. Experimental assay conditions were optimized so that both DNA hybridization and immunological reactions can be achieved simultaneously in the same well and buffer and all at the same temperature. A generic detection system based on the precipitation of an insoluble colorimetric substrate in the presence of enzyme-labeled antibodies or streptavidin was proposed. The optical density of each spot was correlated to the corresponding analyte concentration. The influence of critical parameters on CombOLISA performance such as serum concentration was studied. Calibration curves and sensitivity thresholds were established for each parameter. Serial dilutions of serum were correlated to results obtained with validated immunoassay platforms such as a microplate enzyme-linked immunosorbent assay or the VIDAS automat. Also, several HIV- and HBV-infected serum samples were tested independently by CombOLISA and VIDAS. Coefficients of variation for genomic and proteomic parameters vs spot density were below 15%.

Antibodies, Viral↗
PubMed2002

Comparative genomics identifies the genetic islands that distinguish Neisseria meningitidis, the agent of cerebrospinal meningitis, from other Neisseria species.

Neisseria meningitidis colonizes the nasopharynx and, unlike commensal Neisseria species, is capable of entering the bloodstream, crossing the blood-brain barrier, and invading the meninges. The other pathogenic Neisseria species, Neisseria gonorrhoeae, generally causes an infection which is localized to the genitourinary tract. In order to investigate the genetic basis of this difference in disease profiles, we used a strategy of genomic comparison. We used DNA arrays to compare the genome of N. meningitidis with those of N. gonorrhoeae and Neisseria lactamica, a commensal of the nasopharynx. We thus identified sequences conserved among a representative set of virulent strains which are either specific to N. meningitidis or shared with N. gonorrhoeae but absent from N. lactamica. Though these bacteria express dramatically different pathogenicities, these meningococcal sequences were limited and, in contrast to what has been found in other pathogenic bacterial species, they are not organized in large chromosomal islands.

Bacterial Proteins↗