Biomedical subjects

Sandrine Baghdoyan

Publications and source records attributed to Sandrine Baghdoyan.

3 recordsLinked to original sources

PubMed2005

Id2 reverses cell cycle arrest induced by {gamma}-irradiation in human HaCaT keratinocytes.

Id2 plays a key role in epithelial cells, regulating differentiation, the cell cycle, and proliferation. Because human skin constantly renews itself and is the first target of irradiation, it is of primary interest to evaluate whether such a gene may be regulated in keratinocytes exposed to ionizing radiation. We show here that Id2 is induced in response to gamma-irradiation and have investigated the consequence of this regulation on cell fate. Using RNA interference, we observed that Id2 extinction significantly reduces cell growth in human keratinocytes through the control of the G(1)-S transition of the cell cycle. We have investigated whether the impact of Id2 on the cell cycle may have a physiological role on the cell's ability to cope with radiative stress. Indeed, when Id2 is down-regulated through interfering RNA, cells are more sensitive to irradiation. Conversely, when Id2 is overexpressed, this somehow protects the cell. We propose that Id2 favors reentering the cell cycle after radiation-induced cell cycle arrest to permit the recovery of keratinocytes exposed to ionizing radiation.

Cell Cycle↗

PubMed2005

[Cell microarrays and functional genomics].

With the complete sequencing of the human genome, research priorities have shifted from the identification of genes to the elucidation of their function. Methods currently used by scientists to characterize gene function, such as knock-out mice, are based upon loss of protein function and analysis of the resulting phenotypes to infer a potential role for the protein under scrutiny. Until now, these methods have been successful but time consuming and only a few genes at a time could be analyzed. Cell microarrays allow to simultaneously transfect thousands of different nucleic acid molecules, RNA or DNA, into adherent cells. It is then possible to analyze a large pallet of resulting phenotypes in clusters of transfected cells. We are currently manufacturing cell microarrays with collections of full-length cDNA cloned in expression vectors (gain of function analyses) or siRNA (loss of function studies) to unravel function of genes involved in differentiation and proliferation of human cells. Although there are still some technological difficulties to overcome, the potential for cell microarrays to speed up functional exploration of genomes is very promising.

Cells, Cultured↗

PubMed2004

Quantitative analysis of highly parallel transfection in cell microarrays.

As more genomes are sequenced, we are facing the challenge of rapidly unraveling the functions of genes. To that end, cell microarrays have recently been described that transfect thousands of nucleic acids in parallel and can be used to analyze the phenotypic consequences of such perturbations. As many parameters can influence the efficacy of transfection in such a format, we describe some important features in manufacturing cell microarrays that may improve reliability and efficiency of both plasmid DNA and siRNA transfection. We have also developed image analysis software that allows automatic detection of cell clusters, quantification of transfection efficiency and levels of expression/extinction of genes. Along with cell microarrays, this bioinformatic tool should expedite functional exploration of the human genome.

Automation↗