Project description:We sought to identify critical factors regulating muscle stem cell activation and commitment, and determined through loss-of-function analyses that HMGA2 (high mobility group AT-hook 2) is a key regulator of myogenesis both in vitro and in vivo. mRNAs were isolated from Hmga2 -/- and Hmga2 +/+ mice myoblasts, and a microarray experiment was performed.
Project description:The high-mobility-group (HMG) proteins are the most abundant non-histone chromatin-associated proteins. Here we deciphered the role of the high mobility group AT-hook protein 2 (HMGA2) during lung development by analyzing the lung of Hmga2 deficient mice (Hmga2-/-).We found that Hmga2 is expressed in the mouse embryonic lung at the distal airways. Analysis of Hmga2-/- mice showed that Hmga2 is required for proper cell proliferation and distal epithelium differentiation during embryonic lung development. Hmga2 knockout (KO) led to enhanced canonical WNT signaling due to an increased expression of secreted WNT glycoproteins Wnt2b, Wnt7b and Wnt11 as well as a reduction of the WNT signaling antagonizing proteins GATA6 (GATA binding protein 6) and FZD2 (frizzled homolog 2). Comparison of Hmga2-/- with Hmga2+/+ mice by Affymetrix microarray-based expression analysis of embryonic lung revealed an increased expression of genes whose products participate in cell cycle and canonical Wnt signaling. Affymetrix microarray transcriptome analysis of Hmga2-/- and Hmga2+/+ embryonic lung (E18.5) was performed and analyzed
Project description:We sought to identify critical factors regulating muscle stem cell activation and commitment, and determined through loss-of-function analyses that HMGA2 (high mobility group AT-hook 2) is a key regulator of myogenesis both in vitro and in vivo.
Project description:The high-mobility-group (HMG) proteins are the most abundant non-histone chromatin-associated proteins. Here we deciphered the role of the high mobility group AT-hook protein 2 (HMGA2) during lung development by analyzing the lung of Hmga2 deficient mice (Hmga2-/-).We found that Hmga2 is expressed in the mouse embryonic lung at the distal airways. Analysis of Hmga2-/- mice showed that Hmga2 is required for proper cell proliferation and distal epithelium differentiation during embryonic lung development. Hmga2 knockout (KO) led to enhanced canonical WNT signaling due to an increased expression of secreted WNT glycoproteins Wnt2b, Wnt7b and Wnt11 as well as a reduction of the WNT signaling antagonizing proteins GATA6 (GATA binding protein 6) and FZD2 (frizzled homolog 2). Comparison of Hmga2-/- with Hmga2+/+ mice by Affymetrix microarray-based expression analysis of embryonic lung revealed an increased expression of genes whose products participate in cell cycle and canonical Wnt signaling.
Project description:Overexpression of high mobility group AT-hook 2 (HMGA2) associated with truncations of its 3’ untranslated region (UTR) with let-7 micro RNA-complementary sequences have been identified in patients with paroxysmal nocturnal hemoglobinuria (PNH). Here, we generated transgenic mice (∆Hmga2 mice) with a 3’UTR-trncated Hmga2 cDNA that overexpress Hmga2 mRNA and protein in hematopoietic organs. ∆Hmga2 mice showed proliferative hematopoiesis that mimicked a myeloproliferative neoplasm (MPN)-like phenotype with increased numbers of all lineages of peripheral blood cells, hypercellular bone marrow (BM), splenomegaly with extramedullary erythropoiesis, and erythropoietin-independent erythroid colony formation compared to wild-type mice. ∆Hmga2 BM-derived cells took over most of hematopoiesis in competitive repopulations during serial BM transplants. When we bred mice with circulating PNH cells (Piga- mice) with ∆Hmga2 mice, the lack of GPI-linked proteins did not add an additional clonal advantage to the ∆Hmga2+ cells. In summary, our results showed that the overexpression of a 3’UTR-truncated Hmga2 leads to a proliferative hematopoiesis with clonal advantage, which may explain clonal expansion in PNH or MPN at the level of HSC.
Project description:Overexpression of high mobility group AT-hook 2 (HMGA2) associated with truncations of its 3’ untranslated region (UTR) with let-7 micro RNA-complementary sequences have been identified in patients with paroxysmal nocturnal hemoglobinuria (PNH). Here, we generated transgenic mice (∆Hmga2 mice) with a 3’UTR-trncated Hmga2 cDNA that overexpress Hmga2 mRNA and protein in hematopoietic organs. ∆Hmga2 mice showed proliferative hematopoiesis that mimicked a myeloproliferative neoplasm (MPN)-like phenotype with increased numbers of all lineages of peripheral blood cells, hypercellular bone marrow (BM), splenomegaly with extramedullary erythropoiesis, and erythropoietin-independent erythroid colony formation compared to wild-type mice. ∆Hmga2 BM-derived cells took over most of hematopoiesis in competitive repopulations during serial BM transplants. When we bred mice with circulating PNH cells (Piga- mice) with ∆Hmga2 mice, the lack of GPI-linked proteins did not add an additional clonal advantage to the ∆Hmga2+ cells. In summary, our results showed that the overexpression of a 3’UTR-truncated Hmga2 leads to a proliferative hematopoiesis with clonal advantage, which may explain clonal expansion in PNH or MPN at the level of HSC. Eight independent preparations of RNA, which included each 2 samples of KLS cells and MEP cells from ∆Hmga2 mice and 2 each from WT mice. Each preparation was made from 4 or 6 mice.
Project description:The transcription regulator High Mobility Group AT-Hook 2 (HMGA2) plays an important role in many types of cancers, but the molecular mechanisms are not fully elucidated. We found by knock-down studies that HMGA2 controls expression of ATF4 and the enzymes in the serine synthesis pathway in triple negative breast cancer cells, and that HMGA2 expression correlates with poor clinical outcome in ER negative breast cancers. Furthermore, we found that the metabolism was dysregulated in cells with reduced HMGA2 expression, which affected their response to mitochondrial stressors and to changed carbon sources. Altogether, our findings demonstrate that HMGA2 is a regulator of serine biosynthesis and metabolism, consistent with the well-known role of HMGA2 as a regulator of proliferation, epithelial-mesenchymal transition and stemness.
Project description:The molecular events that mediate the epithelial to mesenchymal transition (EMT) in endometrial cancer remain poorly understood. Using cDNA microarrays, we analyzed a group of endometrial carcinosarcomas (ECS), a true example of EMT in vivo, and we compared their gene expression profiles with those obtained from a group of endometrioid endometrial carcinomas (EEC). The HMGA2 gene (High Mobility Group AT-hook 2), an embryonic nuclear factor that mediates EMT in various tumour models, was among the genes overexpressed in ECS, and HMGA2 overexpression was confirmed in 54% of ECSs by qRT-PCR and immunohistochemistry. Moreover, we found a significant inverse correlation between the expression of HMGA2 and let-7b, a member of the let-7 family of miRNAs that represses HMGA2 expression. These changes were also associated with overexpression of Lin28B, a suppressor of microRNA biogenesis implicated in cancer progression and metastasis. Finally, HMGA2 overexpression, which was detected in less than 3% of EECs, was observed in many non-endometrioid carcinomas (46%). For the first time, we describe a role for HMGA2 in both the process of EMT that contributes to endometrial carcinogenesis and in the acquisition of aggressive phenotypes by this neoplasia. Moreover, we demonstrate changes in the expression of genes modulating processes such as EMT, muscle differentiation, the expression of cancer testis antigens (CTAs) and the immune response. Identification of new molecular markers in endometrial carcinogenesis 15 endometrial carcinosarcomas and 23 endometrioid endometrial carcinoma
Project description:The JAK2V617F mutation has been detected in ~50% cases of MF. Elevated expression of high mobility group AT hook 2 (HMGA2) also has been frequently observed in patients with MF. Interestingly, upregulation of HMGA2 expression has been found in association with the JAK2V617F mutation in significant cases of MF. However, the contribution of HMGA2 in the pathogenesis of MF remains elusive. To determine the effects of concurrent expression of HMGA2 and JAK2V617F mutation in hematopoiesis, we transduced bone marrow cells from Jak2V617F knock-in mice with lentivirus expressing Hmga2 and performed bone marrow transplantation. In order to assess the effects of Hmga2 overexpression on gene expression, we performed RNA sequencing analysis for the LSK from Jak2VF/+ vector and Jak2VF/+ Hmga2mice.
Project description:A genome-wide survey of transcriptional targets responding to chronic KRAS/MAPK (mitogen-activated protein kinase) pathway activation in rat ovarian surface epithelial cells (ROSE 199) has identified multiple differentially expressed transcriptional regulators including the architectural transcription factor high mobility group AT hook 2 (HMGA2). To elucidate the role of HMGA2 in the transcriptional network affected by oncogenic signaling, we used an integrated approach combining RNAi-mediated silencing, microarray-based expression profiling, computational prediction of transcription factor binding sites in target gene promoters and phenotypic analysis. Knocking-down HMGA2 resulted in the reversion of epithelial-mesenchymal transition, loss of anchorage independence and in a substantial restoration of the gene expression pattern characteristic of non-transformed ROSE cells. Computational prediction of transcription factor binding sites in the promoters of HMGA2-regulated genes and expression profiling revealed a preferential role of activator complex-1 (AP-1) components Fra-1 and JunB in target gene regulation. Forced expression of HMGA2 did not transform normal ovarian epithelial cells, suggesting that HMGA2 up-regulation is not sufficient for inducing the transformed phenotype, but mediates cancer-specific phenotypic traits in cells expressing mutated KRAS and, hence, oncogene addiction.