Project description:This project aims to identify transcriptomic changes in the Down Syndrome mouse model (Ts65Dn) in two brain regions, hippocampus and preoptic area. Also, we aim to identify possible transcriptomics rescue effect in Ts55Dn with viral-mediated overexpression of miR200. In total, we have 3 groups of hippocampal and 3 groups of preotic area tissue (WT control virus, 65Dn control virus and 65Dn miR200 - N=4 per group).
Project description:We have previously shown that transgenic overexpression of the miR-200b/200a/429 cluster prevents mammary tumor development in MTB-IGFIR mice. In this study we evaluated whether the miR-200b/200a/429 cluster could also prevent mammary tumor development from a different oncogene, namely Neu/Erbb2. We found that transgenic overexpression of Neu/Erbb2 in MTB-TAN mice induce rapid mammary tumor development and co-overexpression of the miR-200b/200a/429 cluster with Neu/Erbb2 completely prevent mammary epithelial transformation and tumor development
Project description:We aimed to clarify the role of miR-200b in cisplatin (CDDP) sensitivity in bladder cancer (BCa). CDDP resistant T24 cells (T24RC) were transfected with a miR mimic negative control (NC) or a miR-200b mimic, after which cells were treated with or without CDDP. We found that ectopic miR-200b expression re-sensitized the T24RC cells to CDDP. Gene expression microarray analysis revealed that the combination of miR-200b and CDDP affected genes involved in CDDP sensitivity and cytotoxicity.
Project description:For androgen-independent prostate cancer (AIPC), the current treatment is limited and the prognosis is poor. We previously found miR-200b could inhibit androgen independent proliferation ability of prostate cancer cells, but the mechanism is unclear. MiRNAs plays their role by blocking translation through base-pairing with complementary mRNA and by promoting degradation of target mRNA. Unraveling the miRNA translational silencing network remains a challenge in part because a single miRNA can inhibit multiple mRNA targets and because a single mRNA can be regulated by several distinct miRNAs that act cooperatively. However, proteomics methods provide us useful tools to unravel the target genes network. This study identified the target genes of miR-200b in AIPC. It helps us to understand the mechanism of AIPC and applies several new candidate targets of AIPC treatment.
Project description:A major challenge in Down syndrome (DS) is to understand how the extra-dose of functional chromosome 21 (HSA21) genetic elements can impact on the tissue-specific transcriptome to contribute to phenotypic alterations. MiRNAs are post-transcriptional modulators with genome-wide regulatory effects. Five microRNAs have been identified in HSA21 that are present in triple copy in DS individuals. Interestingly, in the Ts65Dn mouse model of DS two of these miRNAs, miR-155 and miR-802, are also triplicated resulting in its overexpression. In the current work, we have developed a lentiviral miRNA-sponge genetic strategy for miR-155 and miR-802 (Lv-miR155-802T) to identify novel mRNA targets involved in hippocampal function. Hippocampal injection of the lentiviral sponge in Ts65Dn mice reduced miR-155 and miR-802 overexpression. Noticeable lentiviral sponge rescued the expression of the miRNA predicted targets showing the potential of the strategy to identify miRNA dosage-sensitive genes with potential involvement in DS-hippocampal phenotypes.
Project description:A major challenge in Down syndrome (DS) is to understand how the extra-dose of functional chromosome 21 (HSA21) genetic elements can impact on the tissue-specific transcriptome to contribute to phenotypic alterations. MiRNAs are post-transcriptional modulators with genome-wide regulatory effects. Five microRNAs have been identified in HSA21 that are present in triple copy in DS individuals. Interestingly, in the Ts65Dn mouse model of DS two of these miRNAs, miR-155 and miR-802, are also triplicated resulting in its overexpression. In the current work, we have developed a lentiviral miRNA-sponge genetic strategy for miR-155 and miR-802 (Lv-miR155-802T) to identify novel mRNA targets involved in hippocampal function. Hippocampal injection of the lentiviral sponge in Ts65Dn mice reduced miR-155 and miR-802 overexpression. Noticeable lentiviral sponge rescued the expression of the miRNA predicted targets showing the potential of the strategy to identify miRNA dosage-sensitive genes with potential involvement in DS-hippocampal phenotypes. Euploid and trisomic adult mice were bilaterally injected at the level of the ventral hippocampus at selected coordinates (AP=-3.3mm, L=+/- 3mm, DV=-3.3mm and -2.3mm relative to bregma). Up to 108 transducing units (3µl of viral suspensions of Lv-Contol or Lv-miR155-802T) were injected into each hemisphere at a rate of 0.2 µl/min, under the precise control of an infusion pump (Ultramicropump, World Precision Instruments). Mice were euthanized for hippocampus collection at day 23 after administration. Transcriptome of hippocampus of euploid and trisomic mice treated with Lv-Control or Lv-miR155-802T was analysed using an Agilent SurePrint G3 Mouse gene expression 8x60K Microarray (ID 028005). A total RNA 100 ng, obtained using miRNeasy Mini Ki (QIAGEN), were labeled using LowInputQuick Amp Labeling kit (Agilent 5190-2305) following manufacturer instructions. Briefly, mRNA was reverse transcribed in the presence of T7-oligo-dT primer to produce cDNA. cDNA was then in vitro transcribed with T7 RNA polymerase in the presence of Cy3-CTP to produce labeled cRNA. The labeled cRNA was hybridized to the Agilent SurePrint G3 Mouse gene expression 8x60K Microarray (ID 028005) according to the manufacturer's protocol. The arrays were washed, and scanned on an Agilent G2565CA microarray scanner at 100% PMT and 3µm resolution. Intensity data was extracted using the Feature Extraction software (Agilent). Replicates from each genotypes and treatment group were distributed as follows: EU+Lv-Contol n=4, EU+Lv-miR155-802T n=4, TS+Lv-Contol n=5, TS+Lv-miR155-802T n=3.
Project description:Dysregulation of Sonic hedgehog (SHH) signaling may contribute to multiple Down syndrome-associated phenotypes, including cerebellar hypoplasia, congenital heart defects, craniofacial and skeletal dysmorphologies, and Hirschsprung disease. Granule cell precursors isolated from the developing cerebellum of Ts65Dn mice are less responsive to the mitogenic effects of SHH than euploid cells, and a single postnatal dose of the SHH pathway agonist SAG rescues cerebellar morphology and performance on learning and memory tasks in Ts65Dn mice. SAG treatment also normalizes expression levels of OLIG2 in neural progenitor cells derived from human trisomy 21 iPSCs. However, despite evidence that activating SHH signaling rescues Down syndrome-associated phenotypes, chromosome 21 does not encode any canonical components of the SHH pathway. Here, we screened 163 chromosome 21 cDNAs in a series of SHH-responsive cell lines to identify chromosome 21 genes that modulate SHH signaling and confirmed overexpression of trisomic candidate genes using RNA-seq in Ts65Dn and TcMAC21 cerebellum. Our study indicates that some chromosome 21 genes, including DYRK1A, activate SHH signaling while others, such as HMGN1 and MIS18A, inhibit SHH signaling. Moreover, overexpression of genes involved in chromatin structure and mitosis, but not genes previously implicated in ciliogenesis, regulate the SHH pathway. Our data suggest that cerebellar hypoplasia and other phenotypes related to aberrant SHH signaling arise from the net effect of trisomy for multiple chromosome 21 genes rather than the overexpression of a single trisomic gene. Identifying which chromosome 21 genes modulate SHH signaling may also suggest new therapeutic avenues for ameliorating Down syndrome phenotypes.