Project description:Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare, genetic premature aging disorder associated with severe atherosclerosis, often resulting in fatal heart attacks and strokes. Progerin, the mutant protein in HGPS, also is expressed in healthy individuals and may play a role in the development of atherosclerosis during physiologic aging. Here, we provide evidence for a primary involvement of vascular endothelium in the pathogenesis of accelerated atherosclerosis in HGPS. Expression of progerin in cultured human endothelial cells induces a dysfunctional phenotype, manifested by activation of multiple pro-inflammatory, pro-atherogenic genes. In particular, our data implicate endothelial-derived interleukin-1 (IL-1) as a key mediator of a pro-inflammatory vascular phenotype. Endothelial activation also is detectable in a mouse model of HGPS, and appears to be conveyed to neighboring vascular cells via autocrine and paracrine signaling. These new mechanistic insights into the vascular pathobiology of HGPS may have therapeutic implications for this disease. Genome-wide transcriptional profiling was carried out to assess functional phenotypic changes in endothelial cells (EC) as a result of progerin expression. Cultured EC were infected with an adenovirus expressing progerin (Ad-Progerin), and as a control, an adenovirus that did not express any construct (Ad-Null). Experiments were preformed with three different EC cultures.
Project description:The premature aging disease Hutchinson-Gilford Progeria Syndrome (HGPS) is caused by constitutive production of progerin, a mutant form of the nuclear architectural protein lamin A1. Progerin is also sporadically expressed in wild type cells and has been linked to physiological aging. HGPS cells exhibit extensive nuclear defects including abnormal chromatin structure and increased DNA damage. At the organismal level, HGPS affects several tissues particularly of mesenchymal origin. How the cellular defects of HGPS cells lead to the organismal defects has been unclear. To begin to unravel how progerin leads to disease phenotypes, we analyzed time-dependent changes in transcriptional profiles in response to progerin expression in a hTERT-immortalized skin fibroblast cell line expressing either GFP-progerin or the GFP-wt lamin A control Keywords: time course, cell line comparison
Project description:Reprogramming somatic cells to induced pluripotent stem cells (iPSCs) sets their identity back to an embryonic age. This presents a fundamental hurdle for modeling late-onset disorders using iPSC-derived cells. We therefore developed a strategy to induce age-like features in multiple iPSC-derived lineages and tested its impact on modeling Parkinson’s disease (PD). We first describe markers that predict fibroblast donor age and observed the loss of these age-related markers following iPSC induction and re-differentiation into fibroblasts. Remarkably, age-related markers were readily induced in iPSC-derived fibroblasts or neurons following exposure to progerin including dopamine neuron-specific phenotypes such as neuromelanin accumulation. Induced aging in PD-iPSC-derived dopamine neurons revealed disease phenotypes requiring both aging and genetic susceptibility such as frank dendrite degeneration, progressive loss of tyrosine-hydroxylase expression and enlarged mitochondria or Lewy body-precursor inclusions. Our study presents a strategy for inducing age-related cellular properties and enables the modeling of late-onset disease features. Induced pluripotent stem cell-derived midbrain dopamine neurons from a young and old donor overexpressing either GFP or Progerin.
Project description:Hutchinson-Gilford Progeria Syndrome (HGPS) is a rare, genetic premature aging disorder associated with severe atherosclerosis, often resulting in fatal heart attacks and strokes. Progerin, the mutant protein in HGPS, also is expressed in healthy individuals and may play a role in the development of atherosclerosis during physiologic aging. Here, we provide evidence for a primary involvement of vascular endothelium in the pathogenesis of accelerated atherosclerosis in HGPS. Expression of progerin in cultured human endothelial cells induces a dysfunctional phenotype, manifested by activation of multiple pro-inflammatory, pro-atherogenic genes. In particular, our data implicate endothelial-derived interleukin-1 (IL-1) as a key mediator of a pro-inflammatory vascular phenotype. Endothelial activation also is detectable in a mouse model of HGPS, and appears to be conveyed to neighboring vascular cells via autocrine and paracrine signaling. These new mechanistic insights into the vascular pathobiology of HGPS may have therapeutic implications for this disease.
Project description:Hutchinson Gilford Progeria Syndrome is a premature aging disease caused by LMNA gene mutation and the production of a truncated lamin A protein “progerin” that elicits cellular and organismal toxicity. Progerin accumulates in the vasculature, being especially toxic for vascular smooth muscle cells (VSMC). Patients' autopsies show that vessel stiffening, and aortic atherosclerosis is accompanied by VSMC depletion in the medial layer, altered extracellular matrix (ECM), and thickening of the adventitial layer. Mechanisms whereby progerin causes massive VSMC loss and vessel alterations remain poorly understood. Mature VSMC retain phenotypic plasticity and can switch to a synthetic/proliferative phenotype. Here we show that progerin expression in human and mouse VSMC causes a switch towards the synthetic/proliferative phenotype. This switch elicits some level of replication stress in normal cells, which is exacerbated in the presence of progerin, leading to telomere fragility, genomic instability, and ultimately VSMC death. Importantly, calcitriol prevents replication stress, telomere fragility, and genomic instability, reducing VSMC death. In addition, RNAseq analysis shows induction of a profibrotic and proinflammatory aging-associated secretory phenotype upon progerin expression in human primary VSMC. Our data suggest that phenotypic switch-induced replication stress might be an underlying cause of VSMC loss in progeria, which together with loss of contractile features and gain of profibrotic and proinflammatory signatures contribute to vascular stiffness in HGPS. Preventing the phenotypic switch-induced replication stress with compounds such as calcitriol might ameliorate CVD in HGPS patients
Project description:Exon level expression analysis for the HGPS pathological aging study data set to analyze the effect of progerin expression on alternative splicing in keratinocytes of HGPS mice. Analysis of the effect of pathological aging (transgenic progerin expression) on alternative splicing (AS) using exon microarrays to interrogate the differential exon usage of the entire genome of HGPS mice (postnatal day 24 and 35) and their wild-type litter mates. Our results suggests that early expression of progerin impairs developmental splicing but that as progerin accumulates, the number of genes with AS increases, similar to what is observed in aging wild-type mice. This dataset is one of the 2 datasets in the overall study. An additional data set series is available with exon expression analysis of aging wild-type mice to analyze the effect of age on alternative splicing during physiological aging. The two datasets are linked together in the SuperSeries GSE67289. A link to the SuperSeries is available at the bottom of this page. 16 skin keratinocyte samples from 2 different age groups: postnatal day 24 and postnatal day 35, from 8 HGPS samples and 8 genotype negative (wild-type) littermates.
Project description:Exon level expression analysis for the HGPS pathological aging study data set to analyze the effect of progerin expression on alternative splicing in keratinocytes of HGPS mice. Analysis of the effect of pathological aging (transgenic progerin expression) on alternative splicing (AS) using exon microarrays to interrogate the differential exon usage of the entire genome of HGPS mice (postnatal day 24 and 35) and their wild-type litter mates. Our results suggests that early expression of progerin impairs developmental splicing but that as progerin accumulates, the number of genes with AS increases, similar to what is observed in aging wild-type mice. This dataset is one of the 2 datasets in the overall study. An additional data set series is available with exon expression analysis of aging wild-type mice to analyze the effect of age on alternative splicing during physiological aging. The two datasets are linked together in the SuperSeries GSE67289. A link to the SuperSeries is available at the bottom of this page.
Project description:Metabolic dysfunction is a primary feature of Werner syndrome (WS), a human premature aging disease caused by mutations in the gene encoding the Werner (WRN) DNA helicase. WS patients exhibit severe metabolic phenotypes, but the underlying mechanisms are not understood, and whether the metabolic deficit can be targeted for therapeutic intervention has not been determined. Here we report impaired mitophagy and depletion of NAD+, a fundamental ubiquitous molecule, in WS patient samples and WS invertebrate models. WRN regulates transcription of a key NAD+ biosynthetic enzyme nicotinamide nucleotide adenylyltransferase 1 (NMNAT1). NAD+ repletion restores NAD+ metabolic profiles and improves mitochondrial quality through DCT-1 and ULK-1-dependent mitophagy. At the organismal level, NAD+ repletion remarkably extends lifespan and delays accelerated aging, including stem cell dysfunction, in C. elegans and Drosophila melanogaster models of WS. Our findings suggest that accelerated aging in WRN syndrome is mediated by impaired mitochondrial function and mitophagy, and that bolstering cellular NAD+ levels counteracts WS phenotypes.