Project description:B-cell acute lymphoblastic leukemia (B-ALL) is often associated with chromosomal translocations leading to the deregulation of proto-oncogenes. MicroRNAs can also be affected by chromosomal alterations and thus contribute to carcinogenesis. The microRNA miR-125b-1 is over-expressed in B-ALL cases with the t(11;14)(q24;q34) translocation, therefore we sought to determine the role of this microRNA in B-cell fate. We used murine pre-BI cells alongside murine and human leukemic B-cell lines to show that miR-125b expression enhances proliferation by targeting Bright/ARID3a, an activator of immunoglobulin heavy-chain transcription. Accordingly, this target gene was down-regulated in B-ALL patients with the t(11;14)(q24;q34) translocation. Repression of Bright/ARID3A blocked differentiation and conferred a survival advantage to Ba/F3 cells under IL3 starvation. In addition, over-expression of miR-125b protected pre-BI and leukemic B-cell lines from apoptosis through blockade of caspase activation via a mechanism that was independent of p53 and BAK1. In summary, miR-125b can act as an oncogene in B-ALL by targeting ARID3a and mediating its repression, thus leading to a blockage in differentiation, increased proliferation and inhibition of apoptosis.
Project description:B-cell acute lymphoblastic leukemia (B-ALL) is often associated with chromosomal translocations leading to the deregulation of proto-oncogenes. MicroRNAs can also be affected by chromosomal alterations and thus contribute to carcinogenesis. The microRNA miR-125b-1 is over-expressed in B-ALL cases with the t(11;14)(q24;q34) translocation, therefore we sought to determine the role of this microRNA in B-cell fate. We used murine pre-BI cells alongside murine and human leukemic B-cell lines to show that miR-125b expression enhances proliferation by targeting Bright/ARID3a, an activator of immunoglobulin heavy-chain transcription. Accordingly, this target gene was down-regulated in B-ALL patients with the t(11;14)(q24;q34) translocation. Repression of Bright/ARID3A blocked differentiation and conferred a survival advantage to Ba/F3 cells under IL3 starvation. In addition, over-expression of miR-125b protected pre-BI and leukemic B-cell lines from apoptosis through blockade of caspase activation via a mechanism that was independent of p53 and BAK1. In summary, miR-125b can act as an oncogene in B-ALL by targeting ARID3a and mediating its repression, thus leading to a blockage in differentiation, increased proliferation and inhibition of apoptosis. To identify specific targets of mir-125b, we overexpressed miR-125b as well as a control miRNA in 70Z/3 and 18-81 pre-B leukaemia cells. Chemically synthesized miRNA duplexes, called pre-miR-125b and miR-Neg, were purchased from Ambion. The cells were transfected with pre-miRNA at a final concentration of 10 nM using Lipofectamin RNAi MAX (Invitrogen) according to the manufacturer’s instructions. The medium was replaced 8 hours after transfection. RNA samples were harvested at 48 hours post-transfection. 2 independent experiments were carried out for a total of 8 samples labeled with Cy3 dye (one color design).
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
Project description:Arid3a, a transcription factor known for its requirement in B-lymphocyte development, has been recently identified as a member of ES cell pluripotency network. Arid3a is moderately expressed in ES cells, and its expression is gradually increased during differentiation. Since Arid3a shows the highest expression in placenta, we hypothesized that Arid3a may play important roles in TE development. We report that Arid3a is a central regulator of both TE-specific and pluripotency-associated gene expression during ES cell differentiation. While dispensable for self-renewal, we observed that knockdown of Arid3a delays differentiation of ES cells. Induction of Arid3a leads ES cells to promote differentiation, specifically towards TE lineage. Moreover, these Arid3a-overexpressing cells maintained in TE culture media are sufficient to generate functional trophoblast stem-like cells, suggesting roles of Arid3a in TE differentiation. By integrative analyses using the chromosomal targets of Arid3a with expression profiling, we revealed the dual roles of Arid3a, as a direct activator of TE-specific genes and a repressor of pluripotency-associated genes. We further revealed the repressive roles of Arid3a are mediated by histone deacetylases (HDACs). Taken together, our results demonstrate that Arid3a is a critical novel regulator in TE lineage specification. Arid3a ChIP was performed using bioChIP-sequencing. Control ChIP-sequencing was performed using BirA cells. HDAC1 ChIP was performed as native antibody ChIP-sequencing.
Project description:Retroviral contructs containing the full-length murine ARID3A (aka Bright) gene and a GFP gene or the GFP gene alone were used to electroporate the human RAJI B cell line. GFP positive cells were sorted and expanded in vitro. Differences in gene expression between the constructs were identified.
Project description:Transcriptional profiling of human mesenchymal stem cells comparing normoxic MSCs cells with hypoxic MSCs cells. Hypoxia may inhibit senescence of MSCs during expansion. Goal was to determine the effects of hypoxia on global MSCs gene expression.
Project description:Retroviral contructs containing the full-length murine ARID3A (aka Bright) gene and a GFP gene or the GFP gene alone were used to electroporate the human RAJI B cell line. GFP positive cells were sorted and expanded in vitro. Differences in gene expression between the constructs were identified. Total RNA was isolated from 4 independent cell culture replicates of each retroviral construct.