ABSTRACT: Expression data from normal human fibroblasts expressing prelamin A or progerin, untreated or treated with farnesyltransferase inhibitor (FTI)
Project description:We compared the transcriptomes of isogenic diploid fibroblasts expressing progerin or elevated levels of wild-type prelamin A with that of wild-type fibroblasts. We subsequently used the reversion towards normal of two phenotypes, reduced cell growth and dismorphic nuclei, by treatment with farnesyltransferase inhibitor (FTI) or overexpression of ZMPSTE24, as a filtering strategy to identify genes linked to the onset of these two phenotypes.
Project description:We compared the transcriptomes of isogenic diploid fibroblasts expressing progerin or elevated levels of wild-type prelamin A with that of wild-type fibroblasts. We subsequently used the reversion towards normal of two phenotypes, reduced cell growth and dismorphic nuclei, by treatment with farnesyltransferase inhibitor (FTI) or overexpression of ZMPSTE24, as a filtering strategy to identify genes linked to the onset of these two phenotypes. We carried out microarray analyses of gene expression profiling in isogenic fibroblasts lines to identify the subset of genes whose expression patterns are strongly altered upon expression of progerin or elevated levels of wild-type lamin A. A filtering strategy was then used to identify potential key effectors. We searched for genes whose expression was reverted towards normal by treatment with farnesyl transferase inibitors (FTI) in both cell lines for 48 hours, or by overexpression of ZMPSTE24 in cells with elevated levels of prelamin A, conditions that improve cell proliferation and leads to a significant decrease in nuclear membrane abnormalities.
Project description:We analyzed and compared global gene expression changes in fibroblasts from human subjects with HGPS compared to age matched controls. We then treated both control and HGPS fibroblasts with a protein farnesyltransferase inhibitor (FTI), a medication currently used in clinical trials to treat HGPS, to look for a reversal of the gene defects present in HGPS fibroblasts.
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disease that is frequently caused by a de novo point mutation at position 1824 in LMNA. This mutation activates a cryptic splice donor site in exon 11, and leads to an in-frame deletion within the prelamin A mRNA and the production of a dominant negative lamin A protein, known as progerin. Here we show that HGPS cells experience genome-wide alterations in patterns of H3K27me3 deposition, changes in the associations of genomic loci with nuclear lamin A/C, and, at late passages, genome-wide loss of spatial compartmentalization of active and inactive chromatin domains that characterizes chromosome folding in normal cells. We further demonstrate that the H3K27me3 changes associate with gene expression alterations in HGPS cells. Our results support a model that the accumulation of progerin in the nuclear lamina leads to altered H3K27me3 marks in heterochromatin, possibly through the down-regulation of EZH2, and disrupts heterochromatin-lamina interactions. These changes may then lead to the genomic disorganization and changes in transcriptional regulation we observe in HGPS fibroblasts. ChIP-Seq was performed for H3K27me3 and lamin A/C in the human genome in three primary fibroblast cell lines: an HGPS patient (HGPS), normal cells from the father of the HGPS patient (Father), and age-matched normal cells (Age Control). Two biological replicates were performed.
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disease that is frequently caused by a de novo point mutation at position 1824 in LMNA. This mutation activates a cryptic splice donor site in exon 11, and leads to an in-frame deletion within the prelamin A mRNA and the production of a dominant negative lamin A protein, known as progerin. Here we show that HGPS cells experience genome-wide alterations in patterns of H3K27me3 deposition, changes in the associations of genomic loci with nuclear lamin A/C, and, at late passages, genome-wide loss of spatial compartmentalization of active and inactive chromatin domains that characterizes chromosome folding in normal cells. We further demonstrate that the H3K27me3 changes associate with gene expression alterations in HGPS cells. Our results support a model that the accumulation of progerin in the nuclear lamina leads to altered H3K27me3 marks in heterochromatin, possibly through the down-regulation of EZH2, and disrupts heterochromatin-lamina interactions. These changes may then lead to the genomic disorganization and changes in transcriptional regulation we observe in HGPS fibroblasts. Hi-C was performed on three primary fibroblast cell lines: an HGPS patient (passage 17 and 19; HGPS), normal cells from the father of the HGPS patient (passage 18; Father), and age-matched normal cells (passage 20; Age Control).
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disease that is frequently caused by a de novo point mutation at position 1824 in LMNA. This mutation activates a cryptic splice donor site in exon 11, and leads to an in-frame deletion within the prelamin A mRNA and the production of a dominant negative lamin A protein, known as progerin. Here we show that HGPS cells experience genome-wide alterations in patterns of H3K27me3 deposition, changes in the associations of genomic loci with nuclear lamin A/C, and, at late passages, genome-wide loss of spatial compartmentalization of active and inactive chromatin domains that characterizes chromosome folding in normal cells. We further demonstrate that the H3K27me3 changes associate with gene expression alterations in HGPS cells. Our results support a model that the accumulation of progerin in the nuclear lamina leads to altered H3K27me3 marks in heterochromatin, possibly through the down-regulation of EZH2, and disrupts heterochromatin-lamina interactions. These changes may then lead to the genomic disorganization and changes in transcriptional regulation we observe in HGPS fibroblasts. We analyzed gene expression of primary fibroblasts of a Hutchinson-Gilford progeria syndrome patient, a healthy age-matched control, and the patient's healthy father using the Affymetrix GeneChip Human Genome U133 Plus 2.0 Array platform. Arrays were filtered and normalized using RMA. Two replicates were performed.
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disease that is frequently caused by a de novo point mutation at position 1824 in LMNA. This mutation activates a cryptic splice donor site in exon 11, and leads to an in-frame deletion within the prelamin A mRNA and the production of a dominant negative lamin A protein, known as progerin. Here we show that HGPS cells experience genome-wide alterations in patterns of H3K27me3 deposition, changes in the associations of genomic loci with nuclear lamin A/C, and, at late passages, genome-wide loss of spatial compartmentalization of active and inactive chromatin domains that characterizes chromosome folding in normal cells. We further demonstrate that the H3K27me3 changes associate with gene expression alterations in HGPS cells. Our results support a model that the accumulation of progerin in the nuclear lamina leads to altered H3K27me3 marks in heterochromatin, possibly through the down-regulation of EZH2, and disrupts heterochromatin-lamina interactions. These changes may then lead to the genomic disorganization and changes in transcriptional regulation we observe in HGPS fibroblasts.
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disease that is frequently caused by a de novo point mutation at position 1824 in LMNA. This mutation activates a cryptic splice donor site in exon 11, and leads to an in-frame deletion within the prelamin A mRNA and the production of a dominant negative lamin A protein, known as progerin. Here we show that HGPS cells experience genome-wide alterations in patterns of H3K27me3 deposition, changes in the associations of genomic loci with nuclear lamin A/C, and, at late passages, genome-wide loss of spatial compartmentalization of active and inactive chromatin domains that characterizes chromosome folding in normal cells. We further demonstrate that the H3K27me3 changes associate with gene expression alterations in HGPS cells. Our results support a model that the accumulation of progerin in the nuclear lamina leads to altered H3K27me3 marks in heterochromatin, possibly through the down-regulation of EZH2, and disrupts heterochromatin-lamina interactions. These changes may then lead to the genomic disorganization and changes in transcriptional regulation we observe in HGPS fibroblasts.
Project description:Hutchinson-Gilford progeria syndrome (HGPS) is a premature aging disease that is frequently caused by a de novo point mutation at position 1824 in LMNA. This mutation activates a cryptic splice donor site in exon 11, and leads to an in-frame deletion within the prelamin A mRNA and the production of a dominant negative lamin A protein, known as progerin. Here we show that HGPS cells experience genome-wide alterations in patterns of H3K27me3 deposition, changes in the associations of genomic loci with nuclear lamin A/C, and, at late passages, genome-wide loss of spatial compartmentalization of active and inactive chromatin domains that characterizes chromosome folding in normal cells. We further demonstrate that the H3K27me3 changes associate with gene expression alterations in HGPS cells. Our results support a model that the accumulation of progerin in the nuclear lamina leads to altered H3K27me3 marks in heterochromatin, possibly through the down-regulation of EZH2, and disrupts heterochromatin-lamina interactions. These changes may then lead to the genomic disorganization and changes in transcriptional regulation we observe in HGPS fibroblasts.
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