Project description:We used ChIP-seq to identify possible EGR1 (Early growth response 1) binding sites in Npy, Npy1/2/5/r in the dorso-lateral striatum in C57BL/6J mice.
Project description:Egr1 regulates genes involved in cholesterol biosynthesis in liver. ChIP-chip assays were performed on H4IIE liver cells that were either treated or untreated with insulin for one hour. This experiment includes a custom ChIP-chip design incorporating many genes that are dynamically regulated by insulin signaling. The Egr1 antibody used was from Santa Cruz sc-189. Egr1 ChIP samples from untreated and 1h insulin treated cells were hybridized.
Project description:Egr1 regulates genes involved in cholesterol biosynthesis in liver. ChIP-chip assays were performed on H4IIE liver cells that were either treated or untreated with insulin for one hour. This experiment includes a custom ChIP-chip design incorporating many genes that are dynamically regulated by insulin signaling. The Egr1 antibody used was from Santa Cruz sc-189.
Project description:Neuropeptide Y (NPY) is an endogenous modulator of neuronal activity by regulating GABA and glutamate release. Previously, we found that estradiol modulates NPY expression in the hippocampal dentate gyrus. Here we investigated which estrogen receptor type activation is required for the NPY expression. Further, we determined effects of estrogen receptor activation on NPY release. Finally, we determined the contribution of estrogen-mediated remodeling of the GABAergic and glutamatergic network in relation to changes in coupling with NPY in ovariectomized rats. We found that activation of either estrogen receptor type increases NPY expression as well as NPY release in the dentate gyrus. We also found that compared to OVX rats, estrogen replacement increases the likeness of synergistic/antagonistic coupling between the NPY and GABAergic synapse genes while the glutamatergic synapse genes are less likely coupled with NPY. The data together suggest that estrogen plays a critical role in regulation of activity of the NPY system and its coupling to GABAergic and glutamatergic synapses in female rat dentate gyrus. Two-conditions (E = beta-estradiol replacement vs O = oil) experiment. Biological replicates: 4E, 4O.
Project description:Previous studies have revealed that UV-stimulation of a variety of cells leads to activation of the EGF receptor, induction of Egr1, growth inhibition and apoptosis. On the other hand both Egr1 and EGF receptor activation are implicated in promoting the progression of prostate cancer. We treated M12 tumorigenic prostate epithelial cells which express little Egr1 with UV irradiation which rapidly activated the EGF receptor and elevated Egr1. Treatment with specific EGFR and ERKI/II inhibitors (PD153035 and UO126, respectively) confirmed that the upregulation of Egr1 was downstream of EGFR and ERKI/II Map kinase pathway. ChIP on chip experiments using Egr1 antibody identified 288 significantly bound promoters upon UV stimulation. Of these target genes, 40% had consensus Egr1 site in their promoters, considerably greater than that expected by chance (p < 0.005). The array binding results were validated by PCR analysis of 25 genes using DNA from conventional IP experiment. Affymetrix gene expression analysis of UV treated and control cells confirmed that a significant number of these bound promoters showed gene expression changes. Addition of siRNA to Egr1 confirmed that the gene expression changes were dependent upon Egr1 expression. Addition of EGF led to similar expression changes for nine tested genes. Proliferation and apoptosis assays confirmed that M12 cells undergo growth arrest and apoptosis following UV irradiation. Moreover, addition of EGF also promoted significant growth inhibition. These results indicate the M12 cells undergo a EGF receptor dependent apoptosis response upon UV-stimulation and that Egr1 mediates the regulation of numerous genes downstream of the EGF receptor that are associated with this response. Keywords: UV treatment analysis duplicated experiment for Affymetrix gene expression analysis and Chip-on-Chip analysis.
Project description:Neuropeptide Y (NPY) is an endogenous modulator of neuronal activity by regulating GABA and glutamate release. Previously, we found that estradiol modulates NPY expression in the hippocampal dentate gyrus. Here we investigated which estrogen receptor type activation is required for the NPY expression. Further, we determined effects of estrogen receptor activation on NPY release. Finally, we determined the contribution of estrogen-mediated remodeling of the GABAergic and glutamatergic network in relation to changes in coupling with NPY in ovariectomized rats. We found that activation of either estrogen receptor type increases NPY expression as well as NPY release in the dentate gyrus. We also found that compared to OVX rats, estrogen replacement increases the likeness of synergistic/antagonistic coupling between the NPY and GABAergic synapse genes while the glutamatergic synapse genes are less likely coupled with NPY. The data together suggest that estrogen plays a critical role in regulation of activity of the NPY system and its coupling to GABAergic and glutamatergic synapses in female rat dentate gyrus.
Project description:NPY signalling via osteoblastic Y1 receptors has been shown to control bone mass but also contributes significantly to the control of whole-body insulin secretion and glucose homeostasis in mice through the release of novel factor(s) which are different from the previously implicated osteocalcin. We used microarrays to identify novel endocrine factors regulated by Y1 receptors and involved in the regulation of bone mass and whole-body homeostasis.
Project description:Cortical GABAergic interneurons have been shown to fulfil important roles by inhibiting excitatory principal neurons. Recent transcriptomic studies have confirmed seminal discoveries that used anatomical and electrophysiological methods highlighting the existence of multiple different classes of GABAergic interneurons. However, individual studies have rarely addressed regional specific differences in gene expression in a given subclass of neuron. Using single-cell Patch-RNAseq, we characterised neuropeptide Y (NPY)-positive GABAergic interneurons in superficial layers of the primary auditory cortex and in distal layers of area CA3. We found that more than 300 genes are differentially expressed in NPY-positive neurons between these two brain regions. For example, the AMPA receptor auxiliary subunit Shisa9/CKAMP44 and the 5-HT2a receptor are significantly higher expressed in auditory NPY-positive neurons. These findings guided us to perform pharmacological experiments that revealed a role for 5-HT2a receptors in auditory NPY-positive neurons. Specifically, although the application of 5-HT led to a depolarisation of both auditory and CA3 NPY-positive neurons, the 5-HT2a receptor antagonist ketanserin only reversed membrane potential changes in auditory NPY-positive neurons. Our study demonstrates the potential of single-cell transcriptomic studies in guiding directed pharmacological experiments.
Project description:Therapy-related myeloid neoplasms (t-MN) share many similarities with AML de novo in the elderly. One common factor is that they arise in the setting of chronic inflammation, likely due to advanced age or chemotherapy-induced senescence. Here, we examined the impact of haploinsufficient loss of the del(5q) tumor suppressor gene, EGR1, commonly deleted in high-risk MNs. In mice, under the exogenous inflammatory stress of either serial transplant or successive doses of the alkylating agent ENU, Egr1-haploinsufficient hematopoietic stem cells (HSCs) exhibit a clonal advantage. Complete loss of EGR1 function is incompatible with transformation; mutations of EGR1 are rare and are not observed in the remaining allele in del(5q) patients and complete knockout of Egr1 in mice leads to HSC exhaustion. Using chromatin immunoprecipitation sequencing (ChIP-seq), we identify EGR1 binding sites in human CD34+ cord blood-derived stem and progenitor cells (HSPCs) and show that EGR1 binds genes critical for stem cell differentiation, inflammatory signaling, and the DNA damage response. Notably, in the chromosome 5 sequences frequently deleted in patients, there is a significant enrichment of innate and inflammatory genes, which may confer a fitness advantage in an inflammatory environment. Short hairpin RNA (shRNA) mediated silencing of EGR1 biases HSPCs towards a self-renewal transcriptional signature. In the absence of EGR1, cells upregulate MYC-driven proliferative signals, downregulate CDKN1A (p21), disrupt the DNA damage response, and downregulate inflammation - adaptations anticipated to confer a relative fitness advantage for stem cells especially in an environment of chronic inflammation.