Topic of this work is the involvement of replicative helicases in human premature ageing syndrome. Replicative helicases are ubiquitous and essential during numerous reactions of the DNA metabolism. The family of replicative helicases (RecQL) is involved in the replication/repair of the DNA and in the telomere maintenance. There are 5 enzymes in human and 3 of them are involved in clinically recognizable syndromes: WRN for the Werner syndrome, BLM for the Bloom syndrome and RECQL4 for the Rothmund Thomson syndrome. All are responsive of a high cancer risk due to genomic instability. Molecular and cellular mechanisms involved in these diseases of ageing are unknown. Moreover, for all of them, there is not therapeutic or preventive solution.
For understanding the involved mechanisms we would like to model the 3 diseases with hiPS (human induced Pluripotent Stem cells) from somatic cells of patients. The patient recruitment was organized by the Montpellier and Nîmes public hospitals. The project is to generate a hiPS cell line for the 3 syndromes from fibroblasts and/or blood samples. Then, we could induce differentiation of hiPS to a target cell line of the diseases. Finally we could study the disease development following the genomic instability (karyotype, array-CGH) and the cellular ageing (senescence-associated heterochromatin foci, telomere length). For each mutated enzyme, we will perform a transcriptional profiling (splice, mRNA quantification) and protein studies (western blot). All results will be compared to wild type cells.
Study Type
OBSERVATIONAL
Enrollment
3
Taking of cutaneous cells by biopsy Sample of blood
University Hospital Montpellier
Montpellier, France
Genomic instability : analysis
Molecular analysis of hiPS cell derived from pathological tissue (karyotype, array-CGH)
Time frame: 1 year
Genomic instability : size of telomers
size of the telomers which will be quantified under microscope after fluorescent marking in situ of telomeric sequences (Q-FISH technique)
Time frame: 1 year
Genomic instability : Duplication of centrosomes
duplication of centrosomes which is often associated with chromosomal segregation errors and genomic instability. This analysis will be done by immunolabelling using antibodies specific to the 2 main components of centrosomes, pericentrin and -tubulin.
Time frame: 1 year
cellular ageing : molecular analysis of hiPS cell derived from pathological tissue
Analysis of senescence-associated heterochromatin foci, telomere length (Q-FISH)
Time frame: 2 years
cellular ageing : IPS line with the criteria defined for morphological characterization
expression of specific surface markers (specifics markers : TRA-1-60, SSEA-4), ability to re-differentiate in the 3 embryonic layers (specifics markers : SMA, MAP2, FOXA2)
Time frame: 2 years
cellular ageing : molecular characterization
lengthening of telomeric sequence size (Q-FISH), re-expression of pluripotency genes (QRTPCR), transcriptional profile of iPS cell lines.
Time frame: 2 years
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