Project description:MicroRNAs (miRNAs) post-transcriptionally regulate gene expression by inhibiting protein synthesis of target messenger RNAs (mRNAs). MicroRNA-142 (miR-142), which has tumor-suppressive properties, was functionally deleted by CRISPR/Cas9 knockout in cell lines derived from diffuse large B-cell lymphoma (DLBCL), a highly aggressive tumor that represents about 30% of non-Hodgkin lymphoma worldwide. Mutations in miR-142 affect about 20% of all cases of DLBCL. By proteome analyses, the miR-142 knockout resulted in a consistent up-regulation of 52 but also down-regulation of 41 proteins in the GC-DLBCL lines BJAB and SUDHL4. Various mitochondrial ribosomal proteins were up-regulated in line with their pro-tumorigenic properties, while proteins necessary for MHC-I presentation were down-regulated in accordance with the finding that miR-142 knockout mice have a defective immune response. Of the deregulated proteins/genes, CFL2, CLIC4, STAU1, and TWF1 are known targets of miR-142, and we could additionally confirm AKT1S1, CCNB1, LIMA1, and TFRC as new targets of miR-142-3p or -5p. We further show that seed-sequence mutations of miR-142 can be used to confirm potential targets and that miRNA knockout cell lines might thus be used to identify novel targets of miRNAs. Due to the complex contribution of miRNAs within cellular regulatory networks, in particular when a miRNA highly present in the RISC complex is deleted and can be replaced by other endogenous miRNAs, primary effects on gene expression may be covered by secondary layers of regulation
Project description:Background: Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic disorder, characterized by cardiomyocyte hypertrophy, cardiomyocyte disarray and fibrosis, which has a prevalence of ~1:200-500 and predisposes individuals to sudden death and heart failure. The mechanisms through which diverse HCM-causing mutations cause cardiac dysfunction remain mostly unknown and their identification may reveal new therapeutic avenues. MicroRNAs have emerged as critical regulators of gene expression and disease phenotype in various pathologies. We explored whether miRNAs could play a role in HCM pathogenesis and offer potential therapeutic targets. Methods and Results: Using high-throughput miRNA expression profiling and qPCR analysis in two distinct mouse models of HCM, we found that miR-199a-3p expression levels are upregulated in mutant mice compared to age- and treatment-matched wild-type mice. We also found that miR-199a-3p expression is enriched in cardiac non-myocytes compared to cardiomyocytes. When we expressed miR-199a-3p mimic in cultured primary cardiac non-myocytes and analyzed the conditioned media by proteomics, we found that several ECM proteins (e.g., TSP2, FBLN3, COL11A1, LYOX) were differentially expressed. We confirmed our proteomics findings by qPCR analysis of selected mRNAs and demonstrated that miR-199a-3p mimic expression in cardiac non-myocytes drives upregulation of ECM genes including Tsp2, Fbln3, Pcoc1, Col1a1 and Col3a1. To examine the role of miR-199a-3p in vivo, we inhibited its function using lock-nucleic acid (LNA)-based inhibitors (antimiR-199a-3p) in an HCM mouse model. Our results revealed that progression of cardiac fibrosis is attenuated when miR-199a-3p function is inhibited in mild-to-moderate HCM. Finally, guided by computational target prediction algorithms, we identified mRNAs Cd151 and Itga3 as direct targets of miR-199a-3p and have shown that miR-199a-3p mimic expression negatively regulates AKT activation in cardiac non-myocytes. Conclusions: Altogether, our results suggest that miR-199a-3p may contribute to cardiac fibrosis in HCM through its actions in cardiac non-myocytes. Thus, inhibition of miR-199a-3p in mild-to-moderate HCM may offer therapeutic benefit in combination with complementary approaches that target the primary defect in cardiac myocytes.
Project description:The nuclear acetyltransferase p300 is a dose-dependent and limiting regulator of cardiac hypertrophy. p300 regulates hypertrophy by controlling the expression of specific microRNAs.The objective of this study was to dissect the role of miR-142 during p300 regulated hypertophic growth in vitro and in vivo and to verify its targets. MiR142 and a non target control were overexpressed using lentivirus in primary culture of neonatal cardiac myocytes. Overexpression was checked 48 hour post transfection. Samples include miR142 OE and non target from three different experiments.
Project description:MicroRNAs (miRs), a group of small and non-coding RNAs, negatively regulate gene expression via promoting messenger RNA (mRNA) degradation or blocking mRNA translation. Many miRs have been recognized as biomarkers or possible targets for the diagnosis or therapy of some diseases. Among them, miR-142-3p was involved in the occurrences and progression of various cardiovascular diseases. Previous studies found that miR-142-3p upregulation could ameliorate myocardial ischemia/reperfusion (I/R)-induced transdifferentiation of fibroblasts to myofibroblasts and collagen deposition. miR-142-3p-mediacted autophagy was reported as a novel mechanism towards I/R-induced cardiac injure. Besides, miR-142-3p could mitigate myocardial mitochondrial dysfunction. Thus, it is worth studying whether silencing miR-142-3p may affect the pathological and physiological functions of cardiac fibroblasts.
Project description:We introduce target sites for the microRNA (miRNA) miR-142 into the 3’-untranslated region of the human cytomegalovirus (HCMV) IE2 to study the transcriptional effect of IE2 knock-down on both viral and host genes in cells that express miR-142. When comparing transcriptional data from miR-142 expressing macrophages infected with HCMV to macrophages infected with IE2-miR-142 targeted HCMV, we see a knock-down of IE2 and differential regulation of predicted viral targets of IE2 including IE1, vIL-10 and US29. We then generated fibroblasts expressing miR-142 to study the knock-down of IE2 in a different cellular system and find drastic differences in loss of IE2 on the host transcriptional profile in the two different cell types.