Project description:To induced the atypical progeria symptoms of LMNA R527C mutant mice, mutant and wild type mice were irradiated at 6 weeks of age with doses of 4 Gy. And to examine the pathologic change of mutant mice, mice were sacrificed at day -1and day 7 post-irradiation and spleen was harvested for RNAseq.
Project description:To determine if LMNA R527C mutation affect the arrangement and function of LADs, we performed Lamin A DamID-seq in wild type and mutant LMNA-stablized Hela cells. Reads of Lamin A ChIP-seq in LADs were decreased in mutant cells compared with wild type. These data suggested that the binding affinity of Lamin A to LADs was reduced after R527C mutation
Project description:To determine if LMNA R527C mutation affect the arrangement and function of LADs, we performed Lamin A ChIP-seq in wild type and mutant MSCs. Reads of Lamin A ChIP-seq in LADs were decreased in mutant cells compared with wild type. These data suggested that the binding affinity of Lamin A to LADs was reduced after R527C mutation
Project description:We performed ATAC-seq to examine to chromatin of openness of coding genes in healthy control and LMNA R527C patient-derived MSCs. The reduction of LADs did not increase the accessibility of the promoters flanking coding genes. The genome wide analysis of ATAC-seq showed that openness of coding genes related chromatin was decreased in mutant MSCs.Thus, R527C mutant Lamin A led to dysfunction of LADs and dysregulation of gene transcription, probably, leading to slow down or arrest of cell proliferation and differentiation.
Project description:To gain insights into the molecular pathogenesis of DCM caused by LMNA mutation, a doxycycline-inducible (Dox-Off) gene expression system was used to express either a wild type (WT) or a mutant LMNA containing the pathogenic variant p.Asp300Asn (LMNAD300N) in cardiac myocytes. The LMNAD300N is associated with DCM in patients with atypical progeroid/Werner syndrome and non-syndromic cardiac progeria. Expression of the mutant LMNAD300N protein in cardiac myocytes led to severe fibrosis, apoptosis, cardiac dysfunction, and premature death. RNA-seq was performed (prior to onset of cardiac dysfunction) to identify gene signatures and transcriptional regulators responsible for this phenotype. Mechanistic studies identified activation of E2F/TP53/DDR, as a major mechanism responsible for the pathogenesis of DCM caused by the LMNAD300N mutation.
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a genetic disorder displaying features reminiscent of premature senescence caused by germline mutations in the LMNA gene encoding lamin A and C, essential components of the nuclear lamina. By studying a family with homozygous LMNA mutation (K542N), we showed that HGPS can also be caused by mutations affecting both isoforms, lamin A and C (J Med Genet 2004;41:609M-^V614). With the aim to elucidate the molecular mechanisms underlying the pathogenesis of lamin A/C-related (hereditary) HGPS, we investigated primary cultured skin fibroblasts from affected homozygous K542N carriers (n=3), healthy heterozygotes (n=3), and controls (n=3) for differences in global gene expression using GeneChip Human Genome U133 Plus 2.0 arrays (Affymetrix UK Ltd.).
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a rare genetic disease with widespread phenotypic features resembling premature aging. HGPS was recently shown to be caused by dominant mutations in the LMNA gene, resulting in the in-frame deletion of 50 amino acids near the carboxyl terminus of the encoded lamin A protein. Children with this disease typically succumb to myocardial infarction or stroke caused by severe atherosclerosis at an average age of 13 years. To elucidate further the molecular; pathogenesis of this disease, we compared the gene expression patterns of three HGPS fibroblast cell lines heterozygous for the LMNA mutation with three normal, age-matched cell lines. We defined a set of 361 genes (1.1% of the approximately 33 000 genes analyzed) that showed at least a 2-fold, statistically significant change. The most prominent categories encode transcription factors and extracellular matrix proteins, many of which are known to function in the tissues severely affected in HGPS. The most affected gene, MEOX2/GAX, is a homeobox transcription factor implicated as a negative regulator of mesodermal tissue proliferation. Thus, at the gene expression level, HGPS shows the hallmarks of a developmental disorder affecting mesodermal and mesenchymal cell lineages. The identification of a large number of genes implicated in atherosclerosis is especially valuable, because it provides clues to pathological processes that can now be investigated in HGPS patients or animal models. Experiment Overall Design: Three fibroblast cell lines derived from HGPS patients were compared to three control fibroblast cell lines using Affymetrix HG-U133A and HG-133B probe arrays. Triplicates were used for each cell line. Total RNA was used in the analysis. Quantitation was done by MAS 5.0 software (Affymetrix).
Project description:Hutchinson-Gilford Progeria Syndrome (HGPS) is caused by a point mutation in the LMNA gene that activates a cryptic donor splice site and yields a truncated form of prelamin A called progerin. Small amounts of progerin are also produced during normal aging. Studies with mouse models of HGPS have allowed the recent development of the first therapeutic approaches for this disease. However, none of these earlier works have addressed the aberrant and pathogenic LMNA splicing observed in HGPS patients because of the lack of an appropriate mouse model. We report herein a genetically modified mouse strain that carries the HGPS mutation. These mice accumulate progerin, present histological and transcriptional alterations characteristic of progeroid models, and phenocopy the main clinical manifestations of human HGPS, including shortened life span and bone and cardiovascular aberrations. By using this animal model, we have developed an antisense morpholino–based therapy that prevents the pathogenic Lmna splicing, dramatically reducing the accumulation of progerin and its associated nuclear defects. Treatment of mutant mice with these morpholinos led to a marked amelioration of their progeroid phenotype and substantially extended their life span, supporting the effectiveness of antisense oligonucleotide–based therapies for treating human diseases of accelerated aging. 6 samples, three from LmnaG609G/G609G mice and three from control Lmna+/+ mice
Project description:LMNA encodes nuclear Lamin A/C that tethers lamina-associated domains (LADs) to the nuclear periphery. Mutations in LMNA cause degenerative disorders including the premature aging disorder Hutchinson-Gilford progeria, but the mechanisms are unknown. We report that Ser22-phosphorylated (pS22) Lamin A/C was localized to the nuclear interior in human fibroblasts throughout the cell cycle. pS22-Lamin A/C interacted with a subset of putative active enhancers, not LADs, at locations co-bound by the transcriptional activator c-Jun. In progeria-patient fibroblasts, a subset of pS22-Lamin A/C-binding sites were lost whereas new pS22-Lamin A/C-binding sites emerged in normally quiescent loci. New pS22-Lamin A/C binding was accompanied by increased histone acetylation, increased c-Jun binding, and upregulation of nearby genes implicated in progeria pathophysiology. These results suggest that Lamin A/C regulates gene expression by enhancer binding. Disruption of the gene regulatory rather than LAD tethering function of Lamin A/C presents a novel mechanism for disorders caused by LMNA mutations.