Hutchinson–Gilford progeria syndrome (HGPS, OMIM 176670) is a rare multisystem childhood premature aging disorder linked to mutations in the LMNA gene. The most common HGPS mutation is found at position G608G within exon 11 of the LMNA gene. This mutation results in the deletion of 50 amino acids at the carboxyl-terminal tail of prelamin A, and the truncated protein is called progerin. Progerin only undergoes a subset of the normal post-translational modifications and remains permanently farnesylated. Several attempts to rescue the normal cellular phenotype with farnesyltransferase inhibitors (FTIs) and other compounds have resulted in partial cellular recovery. Using proteomics, we report here that progerin induces changes in the composition of the HGPS nuclear proteome, including alterations to several components of the protein degradation pathways. Consequently, proteasome activity and autophagy are impaired in HGPS cells. To restore protein clearance in HGPS cells, we treated HGPS cultures with sulforaphane (SFN), an antioxidant derived from cruciferous vegetables. We determined that SFN stimulates proteasome activity and autophagy in normal and HGPS fibroblast cultures. Specifically, SFN enhances progerin clearance by autophagy and reverses the phenotypic changes that are the hallmarks of HGPS. Therefore, SFN is a promising therapeutic avenue for children with HGPS.

SummaryHutchinson-Gilford progeria syndrome (HGPS, OMIM 176670) is a rare disorder characterized by segmental accelerated aging and early death from coronary artery disease or stroke. Nearly 90% of HGPS sufferers carry a G608G mutation within exon 11 of LMNA, producing a truncated form of prelamin A, referred to as “progerin”. Here, we report the isolation of naïve multipotent skin-derived precursor (SKP) cells from dermal fibroblast cultures from HGPS donors. These cells form spheres and express the neural crest marker, nestin, in addition to the multipotent markers, OCT4, Sox2, Nanog and TG30; these cells can self-renew and differentiate into smooth muscle cells (SMCs) and fibroblasts. The SMCs derived from the HGPS-SKPs accumulate nuclear progerin with increasing passages. A subset of the HGPS-naïve SKPs express progerin in vitro and in situ in HGPS skin sections. This is the first in vivo evidence that progerin is produced in adult stem cells, and implies that this protein could induce stem cells exhaustion as a mechanism contributing to aging. Our study provides a basis on which to explore therapeutic applications for HGPS stem cells and opens avenues for investigating the pathogenesis of other genetic diseases.

Even though the number of investigated subjects was small and hydrolytic activity was only slightly increased, the results denote that LEKTI might be diminished in AD. The study also disclosed the necessity of functional analyses in addition to genetic investigations to gain further and more detailed insights into the role of LEKTI in AD.

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