A new genetic drug for Hutchinson­Gilford syndrome

P­08.4­01

V. DzianisavaI, K. PiekarowiczI, M. MachowskaI, R. RzepeckiI

INuclear Group, Biotechnology Department, University of Wroclaw, Wroclaw, Poland

Hutchinson–Gilford progeria syndrome (HGPS) is a rare genetic disorder caused by a point mutation in the LMNA gene. A point mutation (C1824T) in exon 11 leads to cryptic splice site appearance and as a result, part of exon 11 is deleted in progerin (mutated lamin A). The missing sequence plays an important role in post­ translational modification. After C­terminus farnesylation and transport into the nucleus, lamin A is released by the proteolytic cleavage and can form the . Progerin remains attached to the nuclear membrane because it lacks the sequence recognized by protease. The accumulation of progerin leads to nuclear envelope disorganization, abnormal chromatin organization and changes in gene expression.

Nowadays HGPS therapy is based mostly on the prevention of cardiovascular diseases because they are the main cause of patient’s deaths. Reported preclinical therapies were based on the reducing progerin level or farnesylation inhibition. Our point is to develop the genetic drug to suppress the progerin expression by RNA interference. siRNAs were designed to recognize the joint of exon 11 and 12 of progerin mRNA. Their specificity and efficiency were assayed with flow cytometry by measuring the fluorescence intensity changes after transfection. Obtained results were confirmed with western blotting. We also examined the effect of the combination of siRNA and lonafarnib, the clinical drug. We aimed to identify if two drugs act as antagonists, is they action additive, or do they display a synergistic activity.

We demonstrated that progerin level could be sufficiently decreased by siRNA without changes in lamin A level. Besides, our results showed an additive effect of genetic drug combination with the clinically approved lonafarnib treatment. This suggests that genetic drug treatment presumably could be performed with approved HGPS treatment.

The research is supported by grant ERA­NET­E­RARE­3/III/TREATHGPS/10/2018 from the Polish Agency NCBR.