Exacerbated atherosclerosis in progeria is prevented by progerin elimination in vascular smooth muscle cells but not endothelial cells

Hutchinson-Gilford progeria syndrome (HGPS) is a rare disease caused by the expression of progerin, a mutant protein that accelerates aging and precipitates death. Given that atherosclerosis complications are the main cause of death in progeria, here we investigated whether progerin-induced atherosclerosis is prevented in HGPSrev-Cdh5-CreERT2 and HGPSrev-SM22α-Cre mice with progerin suppression in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs), respectively. HGPSrev-Cdh5-CreERT2 mice were undistinguishable from HGPSrev mice with ubiquitous progerin expression, in contrast with the ameliorated progeroid phenotype of HGPSrev-SM22α-Cre mice. To study atherosclerosis, we generated atheroprone mouse models by overexpressing a PCSK9 gain-of-function mutant. While HGPSrev-Cdh5-CreERT2 and HGPSrev mice developed a similar level of excessive atherosclerosis, plaque development in HGPSrev-SM22α-Cre mice was reduced to wild-type levels. Our studies demonstrate that progerin suppression in VSMCs, but not in ECs, prevents exacerbated atherosclerosis in progeroid mice

Cardiovascular Progerin Suppression and lamin A Restoration Rescues Hutchinson-Gilford Progeria Syndrome.

Background: Hutchinson-Gilford progeria syndrome (HGPS) is a rare disorder characterized by premature aging and death mainly due to myocardial infarction, stroke, or heart failure. The disease is provoked by progerin, a variant of lamin A expressed in most differentiated cells. Patients look healthy at birth, and symptoms typically emerge in the first or second year of life. Assessing the reversibility of progerin-induced damage and the relative contribution of specific cell types is critical to determining the potential benefits of late treatment and to developing new therapies. Methods: We used CRISPR/Cas9 technology to generate LmnaHGPSrev/HGPSrev (HGPSrev) mice engineered to ubiquitously express progerin while lacking lamin A and allowing progerin suppression and lamin A restoration in a time- and cell-type-specific manner upon Cre recombinase activation. We characterized the phenotype of HGPSrev mice and crossed them with Cre transgenic lines to assess the effects of suppressing progerin and restoring lamin A ubiquitously at different disease stages as well as specifically in vascular smooth muscle cells (VSMCs) and cardiomyocytes. Results: Like HGPS patients, HGPSrev mice appear healthy at birth and progressively develop HGPS symptoms, including failure to thrive, lipodystrophy, VSMC loss, vascular fibrosis, electrocardiographic anomalies, and precocious death (median lifespan of 15 months versus 26 months in wild-type controls, p<0.0001). Ubiquitous progerin suppression and lamin A restoration significantly extended lifespan when induced in 6-month-old mildly symptomatic mice and even in severely ill animals aged 13 months, although the benefit was much more pronounced upon early intervention (84.5% lifespan extension in mildly symptomatic mice, p<0.0001, and 6.7% in severely ill mice, p<0.01). Remarkably, major vascular alterations were prevented and lifespan normalized in HGPSrev mice when progerin suppression and lamin A restoration were restricted to VSMCs and cardiomyocytes. Conclusions: HGPSrev mice constitute a new experimental model for advancing knowledge of HGPS. Our findings suggest that it is never too late to treat HGPS, although benefit is much more pronounced when progerin is targeted in mice with mild symptoms. Despite the broad expression pattern of progerin and its deleterious effects in many organs, restricting its suppression to VSMCs and cardiomyocytes is sufficient to prevent vascular disease and normalize lifespan

Physiological and Pathological Vascular Aging

Aging is a risk factor for cardiovascular diseases. Through aging, blood vessels become stiffer, less elastic and, thus, with less ability to contract. The objectives of this chapter are to review (i) recent progresses in the characterization of physiological and pathological vascular aging and (ii) in vitro platforms to study vascular aging. Initially, we will discuss the causes and biomarkers of vascular aging. Then we will discuss the main characteristics related to physiological and pathological aging including (i) altered ECM remodeling (e.g. composition, mechanical properties, degradation, calcification of the ECM during aging), (ii) enhanced fibrosis (e.g. causes and mechanisms), (iii) vascular cell dysfunction triggered by chronic oxidative stress, inflammation or senescence, and (iv) altered responses of vascular cells to flow shear stress. Finally, we will discuss in vitro systems to study vascular aging, particularly the effect of biomechanics in aged cells as well as the effect of drugs during vascular aging