The gene encoding the hematopoietic stem cell regulator CCN3 (NOV) is under direct cytokine control through the transcription factors STAT5a/b.
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ABSTRACT: Cytokines control the biology of hematopoietic stem and progenitor cells in part through the transcription factors STAT5a/b. CCN3/NOV has been reported as a positive regulator of hematopoietic stem and progenitor cells. We report microarray analyses of Lineage- Sca-1+ c-Kit+ (KSL) cells in the presence and absence of STAT5a/b. Expression of the ccn3 gene was induced over 100-fold in control, but not STAT5a/b-null cells, upon stimulation with a cocktail containing IL-3, IL-6, SCF, TPO and Flt3 ligand. Among the cytokines, IL-3 elevated ccn3 mRNA level in Lineage- c-Kit+ (KL) cells and 32D cells. ChIP assays using 32D cells revealed IL-3-induced binding of STAT5a/b to a GAS site in the ccn3 gene promoter. This is the first report to link two molecules with importance in the regulation of HSCs, CCN3 and STAT5a/b. We report that the regulation and expression of the ccn3 gene is directly controlled by IL-3 through the transcription factors STAT5a/b.
Project description:Cytokines control the biology of hematopoietic stem and progenitor cells in part through the transcription factors STAT5a/b. CCN3/NOV has been reported as a positive regulator of hematopoietic stem and progenitor cells. We report microarray analyses of Lineage- Sca-1+ c-Kit+ (KSL) cells in the presence and absence of STAT5a/b. Expression of the ccn3 gene was induced over 100-fold in control, but not STAT5a/b-null cells, upon stimulation with a cocktail containing IL-3, IL-6, SCF, TPO and Flt3 ligand. Among the cytokines, IL-3 elevated ccn3 mRNA level in Lineage- c-Kit+ (KL) cells and 32D cells. ChIP assays using 32D cells revealed IL-3-induced binding of STAT5a/b to a GAS site in the ccn3 gene promoter. This is the first report to link two molecules with importance in the regulation of HSCs, CCN3 and STAT5a/b. We report that the regulation and expression of the ccn3 gene is directly controlled by IL-3 through the transcription factors STAT5a/b. Six Control and Six Stat5a/b-null KSL cells, including three biological replications, were unstimulated or stimulated with a cocktail containing IL-3, IL-6, SCF, TPO and FL.
Project description:Transcriptome sequencing analysis of Hs578T control (CTRL sh) and CCN3 knockdown (CCN3 sh) cell lines. CCN3, also known as nephroblastoma overexpressed (NOV, NOVH), has been associated with cell migration, invasion, angiogenesis, adhesion and proliferation in several cancer types like Ewing’s sarcoma, glioma, prostate cancer, hepatocellular carcinoma, clear cell renal cell carcinoma, chondrosarcoma and melanoma. These results provide information about gene expression affected by CCN3 in triple-negative breast cancer cell lines.
Project description:IL-17A and F are critical cytokines in anti-microbial immunity but also contribute to auto-immune pathologies. Recent evidence suggests that they may be differentially produced by T-helper (Th) cells but the underlying mechanisms remain unknown. To address this question, a logical model containing 82 components and 136 regulatory links was developed and calibrated with original flow cytometry data using naive CD4+ T cells in conditions inducing either IL-17A or F. Model analyses led to the identification of the transcription factors NFAT2A, STAT5A and Smad2 as key components explaining the differential expression of IL-17A and IL-17F, with STAT5A controlling IL-17F expression, and an interplay of NFAT2A, STAT5A and Smad2 controlling IL-17A expression.
Project description:Total RNA extracted from Hep3B-CCN3 and Hep3B-vector cells were performed in triplicate using the Human OneArray microarray analyses
Project description:CCN3 (NOV), a putative ligand for integrin receptors, is tightly associated with the extracellular matrix and mediates diverse cellular functions, including cell adhesion and proliferation. CCN3 has been shown to negatively regulate growth although it promotes migration in a cell type-specific manner. In this study, overexpression of CCN3 reduces growth and increases intercellular adhesion of breast cancer cells. Interestingly, CCN3 overexpression also led to the formation of multiple pseudopodia that are enriched in actin, CCN3, and vinculin. Breast cancer cells preincubated with exogenous CCN3 protein also induced the same phenotype, indicating that secreted CCN3 is sufficient to induce changes in cell morphology. Surprisingly, extracellular CCN3 is internalized to the early endosomes but not to the membrane protrusions, suggesting pseudopodia-enriched CCN3 may derive from a different source. The presence of an intracellular variant of CCN3 will be consistent with our finding that the cytoplasmic tail of the gap junction protein connexin43 (Cx43) associates with CCN3. Cx43 is a channel protein permitting intercellular communication to occur. However, neither the channel properties nor the protein levels of Cx43 are affected by the CCN3 protein. In contrast, CCN3 proteins are down-regulated in the absence of Cx43. Finally, we showed that overexpression of CCN3 increases the activity of the small GTPase Rac1, thereby revealing a pathway that links Cx43 directly to actin reorganization.
Project description:Aging is a major risk factor of osteoarthritis, which is characterized by the degeneration of articular cartilage. CCN3, a member of the CCN family, is expressed in cartilage and has various physiological functions during chondrocyte development, differentiation, and regeneration. Here, we examine the role of CCN3 in cartilage maintenance. During aging, the expression of Ccn3 mRNA in mouse primary chondrocytes from knee cartilage increased and showed a positive correlation with p21 and p53 mRNA. Increased accumulation of CCN3 protein was confirmed. To analyze the effects of CCN3 in vitro, either primary cultured human articular chondrocytes or rat chondrosarcoma cell line (RCS) were used. Artificial senescence induced by H2O2 caused a dose-dependent increase in Ccn3 gene and CCN3 protein expression, along with enhanced expression of p21 and p53 mRNA and proteins, as well as SA-β gal activity. Overexpression of CCN3 also enhanced p21 promoter activity via p53. Accordingly, the addition of recombinant CCN3 protein to the culture increased the expression of p21 and p53 mRNAs. We have produced cartilage-specific CCN3-overexpressing transgenic mice, and found degradative changes in knee joints within two months. Inflammatory gene expression was found even in the rib chondrocytes of three-month-old transgenic mice. Similar results were observed in human knee articular chondrocytes from patients at both mRNA and protein levels. These results indicate that CCN3 is a new senescence marker of chondrocytes, and the overexpression of CCN3 in cartilage may in part promote chondrocyte senescence, leading to the degeneration of articular cartilage through the induction of p53 and p21.
Project description:Although the cytokine-inducible transcription factors STAT5a/b promote proliferation of a wide range of cell types, there are cell- and context specific cases in which loss of STAT5a/b results in enhanced cell proliferation. Here we report that loss of STAT5a/b from mouse embryonic fibroblasts (MEFs) leads to enhanced proliferation, which was linked to reduced levels of the cell cycle inhibitor p15INK4B and p21CIP1. We further demonstrate that growth hormone through the transcription factor STAT5a/b enhances expression of the cdkn2B gene and that STAT5a binds to GAS sites within the promoter. We have recently demonstrated that ablation of STAT5a/b from liver results in hepatocellular carcinoma upon a CCl4 insult. We also established that in liver tissue, like in MEFs, STAT5a/b activates expression of the cdkn2B gene. Loss of STAT5a/b led to diminished p15INK4B and increased hepatocyte proliferation. This study for the first time demonstrates that cytokines through STAT5a/b can induce the expression of a key cell cycle inhibitor. These experiments therefore shed a light on the context-specific role of STAT5a/b as tumor suppressors. Control and Stat5a/b-null embryonic fibroblasts (MEFs) cells were stimulated w/o a GH including two biological replications per group (Total four groups)
Project description:STAT5 proteins are vital for lymphocyte development and function. Tyrosine phosphorylation of a C-terminal tyrosine is the key event in cytokine activation of STAT5A and STAT5B. However, the role of STAT5 tyrosine phosphorylation has not been assessed in vivo. Here we generated Stat5a and Stat5b tyrosine mutant knock-in (KI) mice and found that these animals had greatly reduced CD8+ T cell numbers. These cells exhibited profoundly diminished proliferation in response to IL-2, correlating with greatly reduced IL-2-induced pRB and a block in the G1-->S phase transition. The mutant cells also exhibited decreased IL-2-mediated activation of pERK and pAKT, which can in part be attributed to diminished IL-2-induced expression of IL-2R-beta and IL-2R-gamma. Our findings highlight that the tyrosine phosphorylation of both STAT5A and STAT5B is essential for maximal IL-2 signaling and elucidate the molecular basis for achieving an optimal mitogenic effect of IL-2 on CD8+ T cells.