Project description:This model is from the article:
Division of labor by dual feedback regulators controls JAK2/STAT5 signaling over broad ligand range.
Bachmann J, Raue A, Schilling M, Böhm ME, Kreutz C, Kaschek D, Busch H, Gretz N, Lehmann WD, Timmer J, Klingmüller U. Mol Syst Biol.
2011 Jul 19;7:516. 21772264
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Abstract:
Cellular signal transduction is governed by multiple feedback mechanisms to elicit robust cellular decisions. The specific contributions of individual feedback regulators, however, remain unclear. Based on extensive time-resolved data sets in primary erythroid progenitor cells, we established a dynamic pathway model to dissect the roles of the two transcriptional negative feedback regulators of the suppressor of cytokine signaling (SOCS) family, CIS and SOCS3, in JAK2/STAT5 signaling. Facilitated by the model, we calculated the STAT5 response for experimentally unobservable Epo concentrations and provide a quantitative link between cell survival and the integrated response of STAT5 in the nucleus. Model predictions show that the two feedbacks CIS and SOCS3 are most effective at different ligand concentration ranges due to their distinct inhibitory mechanisms. This divided function of dual feedback regulation enables control of STAT5 responses for Epo concentrations that can vary 1000-fold in vivo. Our modeling approach reveals dose-dependent feedback control as key property to regulate STAT5-mediated survival decisions over a broad range of ligand concentrations.
Project description:Cellular signal transduction is governed by multiple feedback mechanisms to elicit robust cellular decisions. We combined mathematical modeling and extensive time-resolved data sets in primary erythroid progenitor cells and dissected the roles of the two transcriptional feedback regulators of the SOCS family, CIS and SOCS3 in JAK2/STAT5 signaling. Our model revealed that both feedbacks are most effective at different ligand concentration ranges. To identify the relevant transcriptional feedback regulators that are involved in attenuation of Epo-induced JAK2-STAT5 signaling in addition to CIS, we performed a time-resolved genome-wide expression profiling of murine erythroid progenitor cells at the colony forming unit erythroid (CFU-E) stage up to 24 and 7 hours after EPO stimulation and in control, repectively. The analysis identified SOCS3 as the only further de novo regulated gene upon Epo-induced JAK2-STAT5 signaling. From subsequent mathematical modeling, we calculated the STAT5 response in previously unobserved Epo concentrations, which provided a quantitative link between cell survival and the integrated response of STAT5 in the nucleus. In conclusion, our combined modeling approach revealed novel insights into the orchestrated action of feedback control to regulate STAT5-mediated survival decisions over a broad range of ligand concentrations. Freshly sorted CFU-E cells were starved for 1 h in Panserin 401 supplemented with BSA and 50 µM β-Mercaptoethanol. Subsequently, cells were stimulated with 0.5 U/ml Epo or left untreated and RNA was extracted at different time points (0,1,2,3,4,5,6,7,8,14,19,24 hrs after Epo stimulation and at 0,1,2,3,4,5,6,7 hrs without Epo treatment) using the RNeasy Mini Plus Kit (Qiagen, Hilden, Germany).
Project description:Cellular signal transduction is governed by multiple feedback mechanisms to elicit robust cellular decisions. We combined mathematical modeling and extensive time-resolved data sets in primary erythroid progenitor cells and dissected the roles of the two transcriptional feedback regulators of the SOCS family, CIS and SOCS3 in JAK2/STAT5 signaling. Our model revealed that both feedbacks are most effective at different ligand concentration ranges. To identify the relevant transcriptional feedback regulators that are involved in attenuation of Epo-induced JAK2-STAT5 signaling in addition to CIS, we performed a time-resolved genome-wide expression profiling of murine erythroid progenitor cells at the colony forming unit erythroid (CFU-E) stage up to 24 and 7 hours after EPO stimulation and in control, repectively. The analysis identified SOCS3 as the only further de novo regulated gene upon Epo-induced JAK2-STAT5 signaling. From subsequent mathematical modeling, we calculated the STAT5 response in previously unobserved Epo concentrations, which provided a quantitative link between cell survival and the integrated response of STAT5 in the nucleus. In conclusion, our combined modeling approach revealed novel insights into the orchestrated action of feedback control to regulate STAT5-mediated survival decisions over a broad range of ligand concentrations.
Project description:While PAX5 is an important tumor suppressor in B-ALL, it is also involved in oncogenic translocations coding for PAX5 fusion proteins. PAX5-JAK2 encodes a protein consisting of the PAX5 DNA-binding region fused to the constitutively active JAK2 kinase domain. Here, we studied the oncogenic function of PAX5-JAK2 in a mouse model expressing it from the endogenous Pax5 locus. The Pax5Jak2/+ mice rapidly developed an aggressive B-ALL in the absence of another cooperating mutation. The DNA-binding function and kinase activity of Pax5-Jak2, as well as IL-7 signaling, all contributed to leukemia development. Interestingly, all Pax5Jak2/+ tumors lost the wild-type Pax5 allele, allowing efficient DNA binding of Pax5-Jak2. While we could not find evidence for a nuclear role of Pax5-Jak2 as an epigenetic regulator, active phosphorylated Stat5 was present at a high level in Pax5Jak2/+ B-ALL tumors, consistent with increased expression of Stat5 target genes. Together, these data identified Pax5-Jak2 as an important nuclear driver of leukemia formation by maintaining phosphorylated Stat5 levels in the nucleus.
Project description:Growth hormone signaling in hepatocytes is fundamentally important. Disruptions in this pathway have led to fatty liver and other metabolic abnormalities. Growth hormone signals through the JAK2/STAT5 pathway. Mice with hepatocyte specific deletion of STAT5 were previously shown to develop fatty liver. Our aim in this study was to determine the effect of deleting JAK2 in hepatocytes on liver gene expression. To do so, we generated animals with hepatocyte specific deletion of JAK2. Hepatocyte-specific JAK2-deficient mice (JAK2L) were generated by mating floxed JAK2 mice (in a mixed (C57Bl/6:129Sv) background) to mice carrying an Alb promoter-regulated Cre transgene on a 100% C57Bl/6 background purchased from the Jackson Labs. Livers were harvested from 8 week old animals for RNA extraction and hybridization.
Project description:Growth hormone signaling in hepatocytes is fundamentally important. Disruptions in this pathway have led to fatty liver and other metabolic abnormalities. Growth hormone signals through the JAK2/STAT5 pathway. Mice with hepatocyte specific deletion of STAT5 were previously shown to develop fatty liver. Our aim in this study was to determine the effect of deleting JAK2 in hepatocytes on liver gene expression. To do so, we generated animals with hepatocyte specific deletion of JAK2.
Project description:Signal Transducers and Activators of Transcription (STATs) are principal transcription factors downstream of cytokine receptors. Although STAT5A is expressed in most tissues it remains to be understood why its premier, non-redundant functions are restricted to prolactin-induced mammary gland development. We report that the ubiquitously expressed Stat5a/b locus is subject to lineage-specific transcriptional control in mammary epithelium. Genome-wide surveys of epigenetic status and transcription factor occupancy uncovered a putative mammary-specific enhancer within the intergenic sequences separating the two Stat5 genes. This region exhibited several hallmarks of genomic enhancers, including DNaseI hypersensitive sites, H3K27 acetylation and binding by GR and MED1. Mammary-specific STAT5 binding was obtained at two canonical STAT5 binding motifs. CRISPR/Cas9-mediated genome editing was used to delete these STAT5 binding sites in mice and determine their biological function. Mutant animals exhibited an 80% reduction of Stat5 levels in mammary epithelium and a concomitant reduction of STAT5-dependent gene expression. Transcriptome analysis identified a class of mammary-restricted genes that was particularly dependent on high STAT5 levels as a result of the intergenic enhancer. Taken together, the mammary-specific enhancer enables a positive feedback circuit that underlies the remarkable abundance of STAT5 and, in turn, controls the efficacy of STAT5-dependent mammary physiology. ChIP-seq for H3K27ac, RNA Pol II, and MED1 in mammary tissues at L1, and ChIP-seq for H3K27ac and GR in mammary tissues at p13. mRNA-seq in WT at L1, line B (GAS2 mutation only) and line C (both GAS1 and GAS2 mutations) at L1 in mammary tissues, and DNase-seq in WT mammary tissues at L1.
Project description:Increasing evidence has revealed a close relationship between circular RNAs (circRNAs) and the regulatory process of cell aging. Exploring the role and mechanism of circRNAs in cellular senescence may help to identify new anti-aging therapeutic targets. In the present study, we investigated the role and regulatory mechanism of hsa_circ_012707 in renal aging.High-throughput sequencing was performed to detect the differential expression of circRNAs in kidney tissues of the old and young groups. qRT-PCR confirmed that the expression of hsa_circ_0127071 in kidney tissue of the old group was significantly higher than that of the young group. SA-β-Gal, Masson Assay is used to evaluate the role of hsa_circ_0127071 in the aging process of kidney tissue.Using RIP, RNA pull down, and WB to study the interaction between hsa_circ_0127071 and aging related pathway proteins.In this study, we found that the expression of hsa_circ_0127071 in kidney tissue of the old group was significantly higher than that of the young group. The activity of JAK2/STAT5 signaling pathway was decreased after silencing EIF4A3, which could delay the aging process. On the basis of silencing EIF4A3 expression, the JAK2/STAT5 signaling pathway was activated by EPO processing, and the senescence of HGMCs increased. After treatment with LOS, the activity of JAK2/STAT5 pathway was decreased and the aging process of HGMCs was delayed. Our findings showed that hsa_circ_0127071 promoted renal aging, and confirmed the regulatory role of EIF4A3/hsa_circ_0127071/JAK2/STAT5 in the regulation of renal aging, providing a new therapeutic target for drug design and early diagnosis.
Project description:Signal Transducers and Activators of Transcription (STATs) are principal transcription factors downstream of cytokine receptors. Although STAT5A is expressed in most tissues it remains to be understood why its premier, non-redundant functions are restricted to prolactin-induced mammary gland development. We report that the ubiquitously expressed Stat5a/b locus is subject to lineage-specific transcriptional control in mammary epithelium. Genome-wide surveys of epigenetic status and transcription factor occupancy uncovered a putative mammary-specific enhancer within the intergenic sequences separating the two Stat5 genes. This region exhibited several hallmarks of genomic enhancers, including DNaseI hypersensitive sites, H3K27 acetylation and binding by GR and MED1. Mammary-specific STAT5 binding was obtained at two canonical STAT5 binding motifs. CRISPR/Cas9-mediated genome editing was used to delete these STAT5 binding sites in mice and determine their biological function. Mutant animals exhibited an 80% reduction of Stat5 levels in mammary epithelium and a concomitant reduction of STAT5-dependent gene expression. Transcriptome analysis identified a class of mammary-restricted genes that was particularly dependent on high STAT5 levels as a result of the intergenic enhancer. Taken together, the mammary-specific enhancer enables a positive feedback circuit that underlies the remarkable abundance of STAT5 and, in turn, controls the efficacy of STAT5-dependent mammary physiology.