Project description:Brown adipocytes, muscle and dorsal dermis descend from precursor cells in the dermomyotome, but the factors that regulate commitment to the brown adipose lineage are unknown. Here, we prospectively isolated and determined the molecular profile of embryonic brown preadipose cells. Brown adipogenic precursor activity in embryos was confined to Pdgfrα+, Myf5Cre-lineage-marked cells. RNAseq analysis identified Early B Cell Factor-2 (Ebf2) as one of the most selectively expressed genes in this cell fraction. Importantly, Ebf2-expressing cells purified from Ebf2-GFP embryos or brown fat tissue did not express myoblast or dermal cell markers and uniformly differentiated into brown adipocytes. Interestingly, Ebf2-expressing cells from white fat tissue in adult animals differentiated into brown-like (or beige) adipocytes. Loss of Ebf2 in brown preadipose cells reduced the expression levels of brown preadipose-signature genes, whereas ectopic Ebf2-expression in myoblasts activated brown preadipose-specific genes. Altogether, these results indicate that Ebf2 specifically marks and regulates the molecular profile of brown preadipose cells. Embryonic fibroblasts, isolated from dorsal body wall of E14.5 Ebf2(GFP)/+ embryos, were further fractionated based on the expression of PDGFRα and Ebf2 (GFP). Affymetrix microarray analysis was prefromed,to compare the gene expression between PDGFRα+ Ebf2(GFP)- and PDGFRα+ Ebf2(GFP)+ cells.
Project description:Brown adipocytes, muscle and dorsal dermis descend from precursor cells in the dermomyotome, but the factors that regulate commitment to the brown adipose lineage are unknown. Here, we prospectively isolated and determined the molecular profile of embryonic brown preadipose cells. Brown adipogenic precursor activity in embryos was confined to Pdgfrα+, Myf5Cre-lineage-marked cells. RNAseq analysis identified Early B Cell Factor-2 (Ebf2) as one of the most selectively expressed genes in this cell fraction. Importantly, Ebf2-expressing cells purified from Ebf2-GFP embryos or brown fat tissue did not express myoblast or dermal cell markers and uniformly differentiated into brown adipocytes. Interestingly, Ebf2-expressing cells from white fat tissue in adult animals differentiated into brown-like (or beige) adipocytes. Loss of Ebf2 in brown preadipose cells reduced the expression levels of brown preadipose-signature genes, whereas ectopic Ebf2-expression in myoblasts activated brown preadipose-specific genes. Altogether, these results indicate that Ebf2 specifically marks and regulates the molecular profile of brown preadipose cells. Embryonic fibroblasts, isolated from dorsal body wall of E14.5 Myf5-CrE;mTmG embryos, were further fractionated based on the expression of PDGFRα, Itga7 and Myf5-cre (GFP). Total mRNA profiles from Myf5-cre(GFP)+PDGFRα+ and Myf5-cre(GFP)+PDGFRα-Itga7+ cells were generated by deep sequenceing
Project description:Brown adipocytes, muscle and dorsal dermis descend from precursor cells in the dermomyotome, but the factors that regulate commitment to the brown adipose lineage are unknown. Here, we prospectively isolated and determined the molecular profile of embryonic brown preadipose cells. Brown adipogenic precursor activity in embryos was confined to Pdgfrα+, Myf5Cre-lineage-marked cells. RNAseq analysis identified Early B Cell Factor-2 (Ebf2) as one of the most selectively expressed genes in this cell fraction. Importantly, Ebf2-expressing cells purified from Ebf2-GFP embryos or brown fat tissue did not express myoblast or dermal cell markers and uniformly differentiated into brown adipocytes. Interestingly, Ebf2-expressing cells from white fat tissue in adult animals differentiated into brown-like (or beige) adipocytes. Loss of Ebf2 in brown preadipose cells reduced the expression levels of brown preadipose-signature genes, whereas ectopic Ebf2-expression in myoblasts activated brown preadipose-specific genes. Altogether, these results indicate that Ebf2 specifically marks and regulates the molecular profile of brown preadipose cells.
Project description:Brown adipocytes, muscle and dorsal dermis descend from precursor cells in the dermomyotome, but the factors that regulate commitment to the brown adipose lineage are unknown. Here, we prospectively isolated and determined the molecular profile of embryonic brown preadipose cells. Brown adipogenic precursor activity in embryos was confined to Pdgfrα+, Myf5Cre-lineage-marked cells. RNAseq analysis identified Early B Cell Factor-2 (Ebf2) as one of the most selectively expressed genes in this cell fraction. Importantly, Ebf2-expressing cells purified from Ebf2-GFP embryos or brown fat tissue did not express myoblast or dermal cell markers and uniformly differentiated into brown adipocytes. Interestingly, Ebf2-expressing cells from white fat tissue in adult animals differentiated into brown-like (or beige) adipocytes. Loss of Ebf2 in brown preadipose cells reduced the expression levels of brown preadipose-signature genes, whereas ectopic Ebf2-expression in myoblasts activated brown preadipose-specific genes. Altogether, these results indicate that Ebf2 specifically marks and regulates the molecular profile of brown preadipose cells.
Project description:Background: The beneficial effect of thermogenic adipocytes in maintaining body weight and protecting against metabolic disorders has raised interest in understanding the regulatory mechanisms defining white and beige adipocyte identity. Although alternative splicing has been shown to propagate adipose browning signals in mice, this has yet to be thoroughly investigated in human adipocytes. Methods: We performed parallel white and beige adipogenic differentiation using primary adipose stem cells from 6 unrelated healthy subjects, and assessed differential gene and isoform expression in mature adipocytes by RNA sequencing. Results: We find 693 exon junctions with robust differential usage between white and beige adipocytes in all 6 subjects, mapping to 507 genes. Importantly, only 8% of these differentially spliced genes are also differentially expressed, indicating that alternative splicing constitutes an additional layer of gene expression regulation during beige adipocyte adipogenic differentiation. Functional classification of alternative isoforms point to a gain of function for key thermogenic regulators such as PPARG, CITED1 and PEMT. We find that a large majority of the splice variants arise from differential usage of transcription start sites (TSSs), with beige-specific TSSs being enriched for PPARγ and MED1 binding compared to white-specific TSSs. Finally, we validate beige specific isoform expression at the protein level for two thermogenic regulators, PPARγ and PEMT. Discussion: These results indicate that differential isoform expression through alternative TSS usage is an important regulatory mechanism for human adipocyte thermogenic specification.
Project description:Background: The beneficial effect of thermogenic adipocytes in maintaining body weight and protecting against metabolic disorders has raised interest in understanding the regulatory mechanisms defining white and beige adipocyte identity. Although alternative splicing has been shown to propagate adipose browning signals in mice, this has yet to be thoroughly investigated in human adipocytes. Methods: We performed parallel white and beige adipogenic differentiation using primary adipose stem cells from 6 unrelated healthy subjects, and assessed differential gene and isoform expression in mature adipocytes by RNA sequencing. Results: We find 693 exon junctions with robust differential usage between white and beige adipocytes in all 6 subjects, mapping to 507 genes. Importantly, only 8% of these differentially spliced genes are also differentially expressed, indicating that alternative splicing constitutes an additional layer of gene expression regulation during beige adipocyte adipogenic differentiation. Functional classification of alternative isoforms point to a gain of function for key thermogenic regulators such as PPARG, CITED1 and PEMT. We find that a large majority of the splice variants arise from differential usage of transcription start sites (TSSs), with beige-specific TSSs being enriched for PPARγ and MED1 binding compared to white-specific TSSs. Finally, we validate beige specific isoform expression at the protein level for two thermogenic regulators, PPARγ and PEMT. Discussion: These results indicate that differential isoform expression through alternative TSS usage is an important regulatory mechanism for human adipocyte thermogenic specification. Code for data processing and analysis are available at https://github.com/sarahhp/splicing_thermogenesis.