Project description:Transcriptional regulation of gene expression plays a fundamental role in coordinating molecular and metabolic responses to stress conditions. The stress-responsive Transcription Factor EB (TFEB), the master controller of lysosomal biogenesis and autophagy, is regulated at the post-translational level by the nutrient-sensitive kinase complex TORC1. However, little is known about the transcriptional regulation of TFEB in physiological and pathological conditions. Here, we show that during starvation, the immediate-early gene EGR1 binds to the TFEB promoter and positively regulates TFEB expression. EGR1 depletion dampened TFEB-mediated transcriptional response to starvation and significantly inhibited cell proliferation in cellular and 3D spheroid models of Birt-Hogg-Dube' (BHD) syndrome, a TFEB-driven inherited cancer condition. Consistently, the MEK1/2 inhibitor Trametinib, known to inhibit EGR1 expression, suppressed the proliferation of BHD patient-derived cancer cells, suggesting that pharmacological inhibition of the EGR1-TFEB axis may represent a therapeutic strategy to counteract constitutive TFEB activation in cancer-associated conditions.
Project description:Human bone marrow stromal cells (BMSCs) are key elements of the hematopoietic environment and they play a central role in bone and bone marrow physiology. However, how key BMSC functions are regulated is largely unknown. We analyzed the role of the immediate early response transcription factor EGR1 as key BMSC regulator and found that EGR1 was highly expressed in prospectively-isolated primary BMSCs, downregulated upon culture, and lower in non-CFU-F-containing CD45neg BM cells. Furthermore, EGR1 expression was lower in proliferative regenerating adult and fetal primary cells compared to adult steady-state BMSCs. Accordingly, EGR1 overexpression markedly decreased BMSC proliferation but considerably improved hematopoietic stroma support function as indicated by an increased production of transplantable CD34+CD90+ hematopoietic stem cells in expansion co-cultures. The improvement of BMSC stroma support function was mediated by increased expression of hematopoietic supporting genes, such as VCAM1 and CCL28. On the other hand, EGR1 knockdown increased ROS-mediated BMSC proliferation, and clearly reduced BMSC hematopoietic stroma support potential. These findings thus show that EGR1 is a key BMSC transcription factor with a dual role in regulating proliferation and hematopoietic stroma support function that is controlling a genetic program to coordinate the specific functions of BMSC in their different biological contexts.
Project description:Transcriptional regulation of gene expression plays a fundamental role in coordinating molecular and metabolic responses to stress conditions. The stress-responsive Transcription Factor EB (TFEB), the master controller of lysosomal biogenesis and autophagy, is regulated at the post-translational level by the nutrient-sensitive kinase complex TORC1. However, little is known about the transcriptional regulation of TFEB in physiological and pathological conditions. Here, we show that during starvation, the immediate-early gene EGR1 binds to the TFEB promoter and positively regulates TFEB expression. EGR1 depletion dampened TFEB-mediated transcriptional response to starvation and significantly inhibited cell proliferation in cellular and 3D spheroid models of Birt-Hogg-Dube' (BHD) syndrome, a TFEB-driven inherited cancer condition. Consistently, the MEK1/2 inhibitor Trametinib, known to inhibit EGR1 expression, suppressed the proliferation of BHD patient-derived cancer cells, suggesting that pharmacological inhibition of the EGR1-TFEB axis may represent a therapeutic strategy to counteract constitutive TFEB activation in cancer-associated conditions.
Project description:To investigate the function of EGR1 in HCC growth, we established EGR1 knock out MHCC97H cells by CRISPR/Cas9 system and EGR1-overexpressing PLC/PRF5 cells. We then performed gene expression profiling analysis using data obtained from RNA-seq of EGR1 knock out MHCC97H cells and parental MHCC97H cells, EGR1-overexpressing PLC/PRF5 cells and control PLC/PRF5 cells.
Project description:Effect of depletion or overexpression of EGR1 on gene expression in HCC cells (deletion in MHCC97H cells, overexpression in PLC/PRF5 cells)
Project description:To gain insight into the function of DNA-PKcs within immune cells, we performed a quantitative phosphoproteomic screen in T cells to identify first order phosphorylation targets of DNA-PKcs. Results indicate that DNA-PKcs phosphorylates the transcription factor Egr1 (early growth response protein 1) at S301. Expression of Egr1 is induced early upon T cell activation and dictates T cell response by modulating expression of cytokines and key costimulatory molecules. Mutation of serine 301 to alanine via CRISPR-Cas9 resulted in increased proteasomal degradation of Egr1 and a decrease in Egr1-dependent transcription of IL2 (interleukin-2) in activated T cells. Our findings identify DNA-PKcs as a critical intermediary link between T cell activation and T cell fate and a novel phosphosite involved in regulating Egr1 activity.
Project description:Experiments measuring effects of overexpression of the transcription factors RUNX1 and CBF-beta (in combination), and TELRUNX1 (fusion protein of TEL and RUNX1). Overexpression is achieved via adenovirus infection of HeLa cell lines. Keywords: other
Project description:We established two representative ABC DLBCL cell lines (TMD8 and OCI-Ly10) with ibrutinib resistance by gradually increasing the concentration of ibrutinib during passage in culture. RNA-seq analysis demonstrated that the BCR pathway gene signature is enriched in resistant cell lines when compared to parental cells. The most upregulated gene is EGR1, a transcription factor that activates multiple oncogenic pathways including MYC and E2F. Elevated EGR1 expression is also observed in ibrutinib-resistant primary mantle cell lymphoma cells when treated with ibrutinib. Using multiple metabolic and genetic approaches, we discovered that overexpression of EGR1 causes metabolic reprogramming to oxidative phosphorylation (OXPHOS) and ibrutinib resistance. Mechanistically, EGR1 mediates metabolic reprogramming through transcriptional activation of PDP1, a phosphatase that dephosphorylates and activates the E1 component of the large pyruvate dehydrogenase complex. Therefore, EGR1-mediated PDP1 activation accelerates intracellular ATP production via the mitochondrial tricarboxylic acid (TCA) cycle, leading to sufficient energy to enhance the proliferation and survival of ibrutinib-resistant lymphoma cells. Finally, we demonstrate that targeting OXPHOS with IM156, a newly developed OXPHOS inhibitor, inhibits the growth of ibrutinib-resistant lymphoma cells both in vitro and in patient-derived xenograft mouse models.