Evaluation of a RING-Bait–Based Proteolysis System for the Targeted Degradation of Progerin in a Cellular Model of Hutchinson-Gilford Progeria Syndrome: A Proof of Concept

Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare genetic disorder characterized by features of premature aging, including growth retardation, alopecia, lipodystrophy, joint contractures, skeletal abnormalities, and cardiovascular disease. It is caused by a mutation in the LMNA gene that leads to the production of progerin, a truncated and toxic form of lamin A. The degradation of progerin could be the solution to this disease, as the presence of lamin C and other laminar proteins is enough to correctly sustain the nuclear lamina. To this end, we explored the application of the RING-Bait system, a proteolytic tool originally developed to target tau oligomers in Alzheimer's disease. This system uses the E3 ubiquitin ligase domain (RING) from TRIM21, coupled with a specific binding module, to tag and degrade target proteins via the ubiquitin-proteasome pathway. Since RING-Bait requires protein oligomerization to function, to prove the applicability of the system, immortalised human fibroblast cells have been transduced with a gene coding for a chimeric progerin in which the protein is fused with a flag called Spy tag and the coding gene for the RING domain fused with the so called Spy catcher domain, which is capable of linking specifically the Spy tag present in the progerin. In this way, the specific targeting of progerin by the RING-Bait system has been achieved and the degradation of progerin through this method has been proven.