Identification of HOTAIR target genes using RNA-seq after overexpression (OE) and downregulation (si) of HOTAIR in human adipose derived stem cells isolated from abdominal (ABD) and gluteofemoral (GF) subcutaneous adipose tissue
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ABSTRACT: Human adipose serived stem cells (ASC) isolated from A and GF adipose tissue obtained from premenopausal women were used to overexpress and downregulate HOTAIR (respectively). RNA-seq was used to study the transcriptome of control and treated cells.
Project description:Human adipose serived stem cells (ASC) isolated from A and GF adipose tissue obtained from premenopausal women were used to perform assess accessible chromatin regions by ATAC-seq, chromatin marks, CTCF and RNAPII identification by chIP-seq
Project description:Identification of HOTAIR target genes using RNA-seq after overexpression (OE) and downregulation (si) of HOTAIR in human adipose derived stem cells isolated from abdominal (ABD) and gluteofemoral (GF) subcutaneous adipose tissue
Project description:Over the past two decades, studies have identified distinct transcriptional signatures between ABD and GF-adipose tissues and between both body shapes. Remarkably, a significant fraction of these depot specific gene expression patterns and more recently the differential chromatin structure profiles have been shown to be conserved during the culture and in vitro differentiation of the precursor cells into mature adipocytes. Our team and others have also shown distinct DNA methylation levels between ABD and GF-AT, that are preserved in isolated ADSCs cultured in vitro. Altogether, these data suggest that depot specific epigenomic profiles contribute significantly to the unique transcriptional profiles of ABD vs GF adipose tissues depots. To extend these earlier studies and to determine how the differential gene expression patterns in different adipose depots may be significantly influenced by chromatin landscape we performed H3K4me3, H3K4me2, H3K27me3, H3K9me3 and CTCF ChIP-seq and ATAC-seq on chromatin isolated from ABD and GF-ADSCs. We paired this with highly differentially expressed genes between ABD and GF-ADSCs. Then, to evaluate the potential role for long range chromatin interactions we utilized an H3K27Ac Hi-ChIP approach to capture putative regulatory loops with at least one anchor being marked by this enhancer associated histone mark. This in-depth analysis of the chromatin structure and organization of ABD and GF-ADSCs provides a better understanding of the intrinsic genomic regulatory features that help define the functionally distinct phenotypes of different subcutaneous adipose tissue depots and how they influence fat distribution in women.
Project description:Over the past two decades, studies have identified distinct transcriptional signatures between ABD and GF-adipose tissues and between both body shapes. Remarkably, a significant fraction of these depot specific gene expression patterns and more recently the differential chromatin structure profiles have been shown to be conserved during the culture and in vitro differentiation of the precursor cells into mature adipocytes. Our team and others have also shown distinct DNA methylation levels between ABD and GF-AT, that are preserved in isolated ADSCs cultured in vitro. Altogether, these data suggest that depot specific epigenomic profiles contribute significantly to the unique transcriptional profiles of ABD vs GF adipose tissues depots. To extend these earlier studies and to determine how the differential gene expression patterns in different adipose depots may be significantly influenced by chromatin landscape we performed H3K4me3, H3K4me2, H3K27me3, H3K9me3 and CTCF ChIP-seq and ATAC-seq on chromatin isolated from ABD and GF-ADSCs. We paired this with highly differentially expressed genes between ABD and GF-ADSCs. Then, to evaluate the potential role for long range chromatin interactions we utilized an H3K27Ac Hi-ChIP approach to capture putative regulatory loops with at least one anchor being marked by this enhancer associated histone mark. This in-depth analysis of the chromatin structure and organization of ABD and GF-ADSCs provides a better understanding of the intrinsic genomic regulatory features that help define the functionally distinct phenotypes of different subcutaneous adipose tissue depots and how they influence fat distribution in women.
Project description:Mechanisms governing regional human adipose tissue (AT) development remain undefined. Here, we show that the long non-coding RNA, HOTAIR (HOX transcript antisense RNA), is exclusively expressed in gluteofemoral AT, where it is essential for adipocyte development. We find that HOTAIR interacts with Polycomb Repressive Complex 2 (PRC2) and identify core HOTAIR-PRC2 target genes involved in adipocyte lineage determination. Repression of target genes coincides with PRC2 promoter occupancy and H3K27 tri-methylation. HOTAIR is also involved in modifying the gluteal adipocyte transcriptome through alternative splicing. Gluteal-specific expression of HOTAIR is maintained by defined regions of open chromatin across the HOTAIR promoter. HOTAIR expression levels can be modified by hormonal (oestrogen, glucocorticoids) and genetic variation (rs1443512 is a HOTAIR eQTL associated with reduced gynoid fat mass in 25,200 individuals). These data identify HOTAIR as a dynamic regulator of the gluteal adipocyte transcriptome and epigenome with functional importance for human regional AT development.
Project description:Objective: Abdominal adiposity is strongly associated with diabetic and cardiovascular comorbidities. The long non-coding RNA HOTAIR (HOX Transcript Antisense Intergenic RNA) is an important epigenetic regulator, with fat depot-specific expression between abdominal subcutaneous adipose tissue (SAT) and gluteal SAT. HOTAIR locates closely with HOXC13, known to strongly associated with human fat distribution. Here, we examined the phenotypic effects of HOTAIR overexpression on abdominal adipogenesis, and hypothesized that HOTAIR-mediated DNA methylation is correlated with transcriptome changes, leading to the regulation of specific genes and the functional pathways. Methods: The expression level of HOTAIR was compared among different fat-depots collected from six healthy, five severe obese, and five uremic subjects, and was correlated with dual-energy x-ray absorptiometry (DXA) defined regional adiposity. The human immortalized preadipocyte was used to assess the phenotypic effects of HOTAIR overexpression on abdominal adipogenesis. The integrative analysis of reduced representation bisulfite sequencing (RRBS) and RNA-sequencing was performed to identify putative genes that are epigenetically regulated by HOTAIR, and the associated signaling pathways. HOTAIR-repressed genes were further validated using RNA/chromatin immunoprecipitation with real-time qPCR and correlated with human body fat distribution. Results: We found that the expression of HOTAIR was high in gluteal SAT, and low in arm/abdominal SAT and visceral (omental) adipose tissue. It could be aberrantly increased in uremic arm SAT. Notably, in severe obese subjects we found that HOTAIR is lowly expressed in abdominal SAT correlating with a higher abdominal adiposity, whereas in uremic patients HOTAIR is highly expressed in arm SAT correlating with lower arm adiposity. HOTAIR overexpression in human immortalized abdominal preadipocyte remarkably suppresses the in vitro adipogenesis. Overall the differentially methylated genes were functionally enriched for nervous system development. We specifically identified 10 HOTAIR-mediated genes showing strong changes of DNA methylation associated with gene expression during abdominal adipogenesis, suggesting potential epigenetic regulation. Two HOTAIR-repressed genes, SLITRK4 and PITPNC1, were further highlighted and validated; presenting an obesity-driven fat-depot specific expression pattern positively correlated with the central body fat distribution. Conclusions: Our study indicated that HOTAIR is an important regulator for abdominal adipogenesis via intricate DNA methylation likely to associate with transcriptional regulation of specific genes, such as SLITRK4 and PITPNC1.
Project description:MDA-MB-231 Breast Cancer Cells were infected by retroviral expression with either VECTOR or HOTAIR. To test the role of polycomb in HOTAIR mediated gene expression, MDA-MB-231 HOTAIR cells were infected with short hairpin retroviral vectors targeting SUZ12 or EZH2. A genetic modification design type is where an organism(s) has had genetic material removed, rearranged, mutagenized or added, such as knock out. genetic_modification_design
Project description:Genome-wide maps of chromatin state in human adipose derived stem cells isolated from abdominal (ABD) and gluteofemoral (GF) subcutaneous adipose tissue
Project description:Accumulating evidence highlights the role of long non-coding RNAs (lncRNA) in cellular homeostasis, and their dysregulation in disease settings. Most lncRNAs function by interacting with proteins or protein complexes. While several orthogonal methods have been developed to identify these proteins, each method has its inherent strengths and limitations. Here, we combine two RNA-centric methods ChIRP-MS and RNA-BioID to obtain a comprehensive list of proteins that interact with the well-known lncRNA HOTAIR. Overexpression of HOTAIR has been associated with a metastasis-promoting phenotype in various cancers. Although HOTAIR is known to bind with PRC2 and LSD1 protein complexes, an unbiased and comprehensive method to map its interactome has not yet been performed. Both ChIRP-MS and RNA-BioID data sets show an association of HOTAIR with mitoribosomes, suggesting HOTAIR has functions independent of its (post-)transcriptional mode-of-action.
Project description:MDA-MB-231 Breast Cancer Cells were infected by retroviral expression with either VECTOR or HOTAIR. To test the role of polycomb in HOTAIR mediated gene expression, MDA-MB-231 HOTAIR cells were infected with short hairpin retroviral vectors targeting SUZ12 or EZH2. A genetic modification design type is where an organism(s) has had genetic material removed, rearranged, mutagenized or added, such as knock out.