Investigation into the human premature ageing disease, Hutchinson Gilford Progeria syndrome, using hTERT immortalised fibroblasts

Abstract

Hutchinson Gilford Progeria syndrome (HGPS) is a rare premature ageing disease affecting children. 80% of “classic” HGPS patients share the same mutation in the LMNA gene that gives rise to characteristics similar to normal human ageing and they usually die in their teens from heart attacks or strokes. Cells taken from progeria patients have a short replicative lifespan in culture and this has necessitated the generation of immortalised progeria cell lines with unlimited growth potential. Evaluation of one such immortalised cell line has revealed loss of progeria cell characteristics, such as nuclear shape abnormalities, and a reversion to a normal nuclear morphology. We attributed this reversion to an increased rate of breakdown of the mutant protein, progerin, which normally causes the nuclear abnormalities. Identification of this underlying mechanism has potential therapeutic applications for HGPS patients. Based on this finding this study demonstrates the effect of an A type lamin target nanobody conjugated to an E3 Ubiquitin ligase, as the first step to a nanobody therapy for HGPS. The development of TAT- lamin A and TAT- progerin fusion proteins, which are capable of transducing into human cells at a desired concentration, allow for future investigation into progerin dose effects. “Atypical” progeria patients have unknown mutations which cause a similar disease but with more varied degrees of severity. The characterisation of an hTERT immortalised cell line, from an “atypical” patient, led to the observation of a genetic instability phenotype, which, in combination with whole exomes sequencing, has enabled the identification of candidate genes within DNA repair and cell cycle regulation. Future identification of another HGPS gene will increase understanding of premature ageing diseases and of normal human ageing.