Vascular senescence in progeria: role of endothelial dysfunction

Area of Science:

• Cellular and Molecular Biology
• Genetics and Genomics
• Aging Research

Background:

• Hutchinson-Gilford progeria syndrome (HGPS) is a rare premature aging disorder caused by mutations in the LMNA gene, leading to the accumulation of toxic progerin protein.
• The primary cause of mortality in HGPS patients is cardiovascular disease, specifically coronary and arterial occlusive disease.
• Murine models show vascular smooth muscle cell (VSMC) loss as a key vascular defect, differing from human HGPS vascular pathology.

Purpose of the Study:

• To elucidate the specific mechanisms underlying vascular disease in human Hutchinson-Gilford progeria syndrome (HGPS).
• To compare the cellular and molecular responses of endothelial cells (ECs) and VSMCs derived from HGPS patients.
• To identify potential therapeutic targets for HGPS-associated vascular complications.

Main Methods:

• Differentiated isogenic endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) from HGPS-induced pluripotent stem cells (iPSCs) and control iPSCs.
• Assessed cellular hallmarks of aging, including nuclear morphology, proliferation, senescence markers (β-galactosidase), telomere length, inflammatory cytokine secretion, DNA damage, heterochromatin, and shelterin protein complex (SPC) expression.
• Quantified specific molecular interactions, including γH2A.X binding to RAP1 and TRF2 binding to lamin A.

Main Results:

• Both HGPS-ECs and HGPS-VSMCs exhibited accelerated aging phenotypes, including nuclear abnormalities, reduced proliferation, and increased senescence markers.
• HGPS-ECs displayed more severe signs of senescence than HGPS-VSMCs, even with lower progerin levels, evidenced by higher β-galactosidase activity, shorter telomeres, and increased DNA damage.
• Distinct molecular alterations were observed: increased γH2A.X binding to RAP1 and reduced TRF2 binding to lamin A were specific to HGPS-ECs, correlating with greater telomere shortening and heterochromatin loss.

Conclusions:

• Progerin accumulation detrimentally affects both endothelial cells and vascular smooth muscle cells in HGPS.
• Endothelial cells are disproportionately vulnerable to progerin-induced cellular dysfunction compared to vascular smooth muscle cells.
• Targeting endothelial cell dysfunction presents a promising therapeutic strategy for managing vascular complications in Hutchinson-Gilford progeria syndrome.