From immature lamin to premature aging: molecular pathways and therapeutic opportunities.
Accelerated aging or progeria has been a puzzling disease for many years. The recent findings involving the lamin A/FACE-1 (substrate/protease) system in the etiology of Hutchinson-Gilford progeria syndrome and related pathologies have shed some light on the mechanisms underlying the development of these devastating conditions. Thus, genetic defects in the nuclear envelope protein prelamin A or in the FACE-1 metalloprotease (also called Zmspte24) involved in prelamin A proteolytic maturation, cause the accumulation of an abnormal form of this protein and the subsequent disruption of nuclear envelope integrity. Recently, we and others have observed how this disruption leads to alterations in chromatin organization, genomic instability, transcriptional changes, and activation of a p53-linked signaling pathway. By using genetic manipulation approaches in mouse, we have shown that lowering prelamin A levels results in a total recovery of Zmpste24-deficient mice from the accelerated aging process. Moreover, p53 nullizygosity allows a modest but significant improvement in the premature aging phenotype, and contributes to delaying the onset of the progeroid condition. On the basis of these results, we propose different potential therapeutic approaches that could be tested in Zmpste24-deficient mice. These strategies, some of which are based on existing drugs, might contribute to the development of effective treatments for these dramatic pathologies.