Cdk8 attenuates lipogenesis by inhibiting SREBP-dependent transcription in Drosophila
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ABSTRACT:
PROVIDER: PRJNA896948 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR30855809.fastq.gz | Fastqsanger.gz | |||
| SRR30855810.fastq.gz | Fastqsanger.gz | |||
| SRR30855811.fastq.gz | Fastqsanger.gz | |||
| SRR30855812.fastq.gz | Fastqsanger.gz | |||
| SRR30855813.fastq.gz | Fastqsanger.gz |
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Project description:Fine-tuning of lipogenic gene expression is important for the maintenance of long-term homeostasis of intracellular lipids. The SREBP family of transcription factors are master regulators that control the transcription of lipogenic and cholesterogenic genes, but the mechanisms modulating SREBP-dependent transcription are still not fully understood. We previously reported that CDK8, a subunit of the transcription co-factor Mediator complex, phosphorylates SREBP at a conserved threonine residue. Here, using Drosophila as a model system, we observed that the phosphodeficient SREBP proteins (SREBP-Thr390Ala) were more stable and more potent in stimulating the expression of lipogenic genes and promoting lipogenesis in vivo than wild-type SREBP. In addition, starvation blocked the effects of wild-type SREBP-induced lipogenic gene transcription, whereas phosphodeficient SREBP was resistant to this effect. Furthermore, our biochemical analyses identified six highly conserved amino acid residues in the N-terminus disordered region of SREBP that are required for its interactions with both Cdk8 and the MED15 subunit of the small Mediator complex. These results support that the concerted actions of Cdk8 and MED15 are essential for the tight regulation of SREBP-dependent transcription.
2022-11-09 | GSE217104 | GEO
Project description:Fine-tuning of lipogenic gene expression is important for the maintenance of long-term homeostasis of intracellular lipids. The SREBP family of transcription factors are master regulators that control the transcription of lipogenic and cholesterogenic genes, but the mechanisms modulating SREBP-dependent transcription are still not fully understood. We previously reported that CDK8, a subunit of the transcription co-factor Mediator complex, phosphorylates SREBP at a conserved threonine residue. Here, using Drosophila as a model system, we observed that the phosphodeficient SREBP proteins (SREBP-Thr390Ala) were more stable and more potent in stimulating the expression of lipogenic genes and promoting lipogenesis in vivo than wild-type SREBP. In addition, starvation blocked the effects of wild-type SREBP-induced lipogenic gene transcription, whereas phosphodeficient SREBP was resistant to this effect. Furthermore, our biochemical analyses identified six highly conserved amino acid residues in the N-terminus disordered region of SREBP that are required for its interactions with both Cdk8 and the MED15 subunit of the small Mediator complex. These results support that the concerted actions of Cdk8 and MED15 are essential for the tight regulation of SREBP-dependent transcription. This article has an associated First Person interview with the first author of the paper.
| S-EPMC9702540 | biostudies-literature
Project description:Background: Lung function is dependent upon the precise regulation of the synthesis, storage, and catabolism of tissue and alveolar lipids. Results: Activation of SREBP (Sterol Response Element Binding Protein) induced lipogenesis in alveolar epithelial cells, causing neutral lipid accumulation, lung inflammation, and tissue remodeling. Conclusions: The accumulation of neutral lipids in type II epithelial cells and alveolar macrophages caused lung inflammation, consistent with findings in lipid storage disorders. Significance: Pulmonary lipotoxicity may contribute to the pathogenesis of lung dysfunction associated with diabetes, obesity, and other metabolic disorders. Genome-wide transcription profiling comparison between doxycycline-exposed SFTPC-rtTAWT/Tg/(tetO)7CMV-CreWT/Tg/Insig1flox/flox/Insig2-/- mice (i.e., Insig1/2∆/∆ ) and Insig1flox/flox/Insig2-/- . Three independent pooled RNA from isolated lung type 2 cells of each genotype were used.
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Project description:Background: Lung function is dependent upon the precise regulation of the synthesis, storage, and catabolism of tissue and alveolar lipids. Results: Activation of SREBP (Sterol Response Element Binding Protein) induced lipogenesis in alveolar epithelial cells, causing neutral lipid accumulation, lung inflammation, and tissue remodeling. Conclusions: The accumulation of neutral lipids in type II epithelial cells and alveolar macrophages caused lung inflammation, consistent with findings in lipid storage disorders. Significance: Pulmonary lipotoxicity may contribute to the pathogenesis of lung dysfunction associated with diabetes, obesity, and other metabolic disorders.
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Project description:We report the role of YAP in promoting de novo lipogenesis through the SREBP transcriptional program. By using paired-end RNA sequencing, we show that transgenic zebrafish livers expressing activted YAP exhibit an increase in SREBP target genes associated with lipogenesis. The paired-end RNA sequencing was performed in larval zebrafish livers at 7 days post fertilization (7 dpf)
2022-02-05 | GSE195711 | GEO
Project description:FAM120A couples SREBP-dependent transcription and splicing of lipogenesis enzymes downstream of mTORC1
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Project description:TF-seq analysis conducted on the same set of lysates identified 3 primary pathways modulated by CDK8 inhibition: suppression of NF-kB and STAT1 and de-repression of AP-1. The results with STAT1 are consistent with literature identifying a role for CDK8 in IFN-driven STAT1 transcriptional activation. In addition, there is patent literature indicating that CDK8 inhibition can suppress NF-kB activation. We expect to see changes in the global RNA-seq expression profiles consistent with the TF-seq data – namely, reduced expression of NF-kB and STAT1 target genes.
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Project description:Paraspeckle protein NONO attenuates vascular calcification by inhibiting BMP2 transcription
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Project description:Biallelic inactivating mutations of the transcription factor 1 gene (TCF1), encoding hepatocyte nuclear factor 1a (HNF1a), were identified in 50% of hepatocellular adenomas (HCA) phenotypically characterized by a striking steatosis. To understand the molecular basis of this aberrant lipid storage, we performed a microarray transcriptome analysis validated by quantitative RT-PCR, western-blotting and lipid profiling. In mutated HCA, we showed a repression of gluconeogenesis coordinated with an activation of glycolysis, citrate shuttle and fatty acid synthesis predicting elevated rates of lipogenesis. Moreover, the strong dowregulation of L-FABP suggests that impaired fatty acid trafficking may also contribute to the fatty phenotype. In addition, transcriptional profile analysis of the observed deregulated genes in non-HNF1a-mutated HCA as well as in non-tumor livers allowed us to define a specific signature of the HNF1a-mutated HCA. In theses tumors, lipid composition was dramatically modified according to the transcriptional deregulations identified in the fatty acid synthetic pathway. Surprisingly, lipogenesis activation did not operate through SREBP-1 and ChREBP that were repressed. We conclude that steatosis in HNF1a-mutated HCA results mainly from an aberrant promotion of lipogenesis that is linked to HNF1a inactivation and that is independent of both SREBP-1 and ChREBP activation. Finally, our findings have potential clinical implications since lipogenesis can be efficiently inhibited by targeted therapies. Keywords: Disease state analysis
2007-05-01 | GSE7473 | GEO
Project description:Insulin integrates hepatic glucose and lipid metabolism, directing nutrients to storage as glycogen and triglyceride. In type 2 diabetes, levels of the former are low and the latter are exaggerated, posing a pathophysiologic and therapeutic conundrum. A branching model1 of insulin signaling, with FoxO1 presiding over glucose production2-5 and Srebp–1c regulating lipogenesis,6-8 provides a potential explanation. Here we illustrate an alternative mechanism that integrates glucose production and lipogenesis under the unifying control of FoxO. Liver–specific ablation of three FoxOs (L–FoxO1,3,4) prevents the induction of glucose–6–phosphatase and the repression of glucokinase during fasting, thus increasing lipogenesis at the expense of glucose production. We document a similar pattern in the early phases of diet-induced insulin resistance, and propose that FoxOs are required to enable the liver to direct nutritionally derived carbons to glucose vs. lipid metabolism. Our data underscore the heterogeneity of hepatic insulin resistance during progression from the metabolic syndrome to overt diabetes, and the conceptual challenge of designing therapies that curtail glucose production without promoting hepatic lipid accumulation. We used microarrays to detail the change of gene expression in liver after knocking out FoxO1,3 and 4. Liver tissue samples were collected from hepatocyte- specific triple FoxO(1,3, and 4) KO and their littermates control (WT) mice after fasting (22 h) or refeeding (4 h). Gene expression was analyzed by microarray. Mice were on a mixed background of C57BL/6J and 129.
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