Project description:Emerging evidence has shown that noncoding RNAs, particularly microRNAs (miRNAs), contribute to the pathogenesis of mood and anxiety disorders, although the molecular mechanisms are poorly understood. Here we show altered levels of miR-17-92 in adult hippocampal neural progenitors have a significant impact in neurogenesis and anxiety- and depression-related behaviors in mice. miR-17-92 deletion in adult neural progenitors causes a decrease, while its overexpression an increase of neurogenesis in the dentate gyrus, through regulating genes in the glucocorticoid pathway, especially serum- and glucocorticoid-inducible protein kinase-1 (Sgk1). miR-17-92 knockout mice show anxiety- and depression-like behaviors, whereas miR-17-92 overexpressing mice exhibit anxiolytic and antidepression-like behaviors. Furthermore, we show that miR-17-92 expression in the adult mouse hippocampus responds to chronic stress, and miR-17-92 rescues proliferation defects, induced by corticosterone, in hippocampal neural progenitors. Our study uncovers a crucial role for miR-17-92 in adult neural progenitors to regulate neurogenesis and anxiety- and depression-like behaviors.
Project description:A network of gene regulatory factors such as transcription factors and microRNAs establish and maintain the gene expression pattern during hematopoiesis. In this network transcription factors regulate each other and are involved in regulatory loops with microRNAs.The microRNA cluster miR-17-92 is located within the MIR17HG gene and encodes for six mature microRNAs. It is important for hematopoietic differentiation and plays a central role in malignant disease. However, the transcription factors downstream of miR-17-92 are largely elusive and the transcriptional regulation of miR-17-92 is not fully understood. Here we show that miR-17-92 forms a regulatory loop with the transcription factor TAL1. The miR-17-92 cluster inhibits expression of TAL1 and indirectly leads to decreased stability of the TAL1 transcriptional complex. We found that TAL1 and its heterodimerization partner E47 regulate miR-17-92 transcriptionally. Furthermore, miR-17-92 negatively influences erythroid differentiation, a process that depends on gene activation by the TAL1 complex. Our data give example of how transcription factor activity is fine-tuned during normal hematopoiesis. We postulate that disturbance of the regulatory loop between TAL1 and the miR-17-92 cluster could be an important step in cancer development and progression.
Project description:Adult beta cells in the pancreas are the sole source of insulin in our body. Beta cell loss or increased demand for insulin, impose metabolic challenges because adult beta cells are generally quiescent and infrequently re-enter the cell division cycle. miR-17-92/106b is a family of proto-oncogene microRNAs, that regulate proliferation in normal tissues and in cancer. Here, we employ mouse genetics to demonstrate a critical role for miR-17-92/106b in glucose homeostasis and in controlling insulin secretion. Mass spectrometry analysis was performed on miR-17-92LoxP/LoxP;106-25-/- MEF lysate, without or with CRE-Adenovirus. miR-17-92LoxP/LoxP;106-25+/+ MEFs with GFP-Adenovirus served as controls. We demonstrate that miR-17-92/106b regulate the adult beta cell mitotic checkpoint and that miR-17-92/106b deficiency results in reduction in beta cell mass in-vivo. Furthermore, protein kinase A (PKA) is a new relevant molecular pathway downstream of miR-17-92/106b in control of adult beta cell division and glucose homeostasis. Therefore, contributes to the understanding of proto-oncogene miRNAs in the normal, untransformed endocrine pancreas, and illustrates new genetic means for regulation of beta cell mitosis and function by non-coding RNAs.
Project description:Knockout of the ubiquitously expressed microRNA-17~92 cluster in mice produces a lethal developmental lung defect. We validated the equally widely expressed pro-apoptotic Bim gene as joint target of miR-17~92 cluster members. To study the contribution of miR-17~92:Bim interaction to miR-17~92 overall function, we set up a system of conditional mutagenesis of the Bim 3’UTR. Blocking miR-17~92:Bim interaction early in development phenocopied the lethal lung phenotype of miR-17~92 ablation. Thus, despite hundreds of overall predicted targets vital miRNA functions can be mediated by a single target gene.
Project description:The miR-17-92 cluster targets mRNAs involved in distinct pathways which either promote or inhibit tumor progression. However, the cellular and molecular mechanisms underlying miR-17~92 cluster mediated pro- or anti- tumorigenic effects has not been studied. In this study, we found that inhibition of colon cancer progression is dictated by quantitatively controlling expression of the miR-17~92 cluster. To identify molecular mechanisms giving rise to the different growth/metastasis patterns, we profiled gene expression in miR-Ctrl, miR-17~92Med and miR-17~92Hi cells using Affymetrix Murine GeneST Arrays.
Project description:Physical exercise stimulates adult hippocampal neurogenesis in mammals, and is considered a relevant strategy for preventing age-related cognitive decline in aging humans. However, its mechanism is controversial. Here, by investigating microRNAs (miRNAs) and their downstream pathways, we uncover that downregulation of miR-135a-5p mediates exercise-induced proliferation of adult NPCs in adult neurogenesis in the mouse hippocampus, likely by activation of phosphatidylinositol (IP3) signaling. Specifically, while overexpression of miR-135 prevents exercise-induced proliferation in the adult mouse hippocampus in vivo and in NPCs in vitro, its inhibition activates NPCs proliferation in resting and aged mice. Label free proteomics and bioinformatics analysis identifies 11 potential targets of miR-135 in NPCs, several of them involved in phosphatidylinositol signaling. Thus, miR-135a is key in mediating exercise-induced adult neurogenesis and opens intriguing perspectives toward the therapeutic exploitation of miR-135 to delay or prevent pathological brain ageing.Physical exercise stimulates adult hippocampal neurogenesis in mammals, and is considered a relevant strategy for preventing age-related cognitive decline in aging humans. However, its mechanism is controversial. Here, by investigating microRNAs (miRNAs) and their downstream pathways, we uncover that downregulation of miR-135a-5p mediates exercise-induced proliferation of adult NPCs in adult neurogenesis in the mouse hippocampus, likely by activation of phosphatidylinositol (IP3) signaling. Specifically, while overexpression of miR-135 prevents exercise-induced proliferation in the adult mouse hippocampus in vivo and in NPCs in vitro, its inhibition activates NPCs proliferation in resting and aged mice. Label free proteomics and bioinformatics analysis identifies 11 potential targets of miR-135 in NPCs, several of them involved in phosphatidylinositol signaling. Thus, miR-135a is key in mediating exercise-induced adult neurogenesis and opens intriguing perspectives toward the therapeutic exploitation of miR-135 to delay or prevent pathological brain ageing.
Project description:The adult heart has been considered as an organ with limited regenerating capability due to mature cardiomyocytes exit the cell cycle and stop proliferating. It has been reported that miR-17-92 cluster plays a key role in cardiomyocyte proliferation. According to the seed sequence, miR-17-92 cluster includes miR-18, miR-19, miR-20 and miR-92 families. Here, we show that intra-cardiac injection of miR-19 mimic into adult mouse hearts protects heart from myocardial infarction injury with reduced apoptosis, enhanced cardiomyocyte proliferation and cardiac regeneration. We performed the RNA-seq profiling in both injection of control mimic and miR-19 mimic post myocardial infarction. The transcriptome analysis indicates that genes related to immune response and cardiac remodeling were repressed by miR-19 in infarcted hearts.
Project description:The miR-17-92 microRNA cluster is often activated in cancer cells, but the identity of its targets remains largely elusive. Here we examined the effects of activation of the entire miR-17-92 cluster on global protein expression in neuroblastoma cells. In this dataset we deposit global mRNA expression data obtained form primary neuroblastoma tumour cells. This data was used to demonstrate negative correlation between TGFB target gene expression and expression of the miR-17-92 cluster.
Project description:Gain of chromosome arm 13q is one of the most prevalent DNA copy number alterations associated with colorectal adenoma-to-carcinoma progression. The oncogenic miR-17-92 cluster, located at 13q, was found to be overexpressed in colorectal cancer and in adenomas harboring 13q gain. However, to what extent overexpression of this group of microRNAs actually drives progression to cancer remains to be resolved. Therefore, we aimed to clarify the role of miR-17-92 cluster in the progression from colorectal adenoma to carcinoma.
In human colorectal adenoma organoids without 13q gain, the miR-17-92 cluster was overexpressed and downstream effects on mRNA expression investigated, along with functional effects in vitro and in vivo.
Comparison of mRNA sequencing results of organoids overexpressing miR-17-92 and cultures transduced with control vector, revealed a miR-17-92 expression signature. This signature appeared to be enriched in an independent series of colorectal cancers and adenomas tissues with 13q gain, confirming that miR-17-92 expression is associated with malignant progression. However, an increase in proliferation rate was not observed in miR-17-92 overexpressing adenoma organoids in vitro. In addition, subcutaneous injection of these organoids in immunodeficient mice was insufficient to cause tumor outgrowth.
Transfecting miR-17-92 cluster in human colon adenoma organoids induces an expression signature that proved to be enriched in both adenomas with 13q gain and in colorectal cancers, supporting its role as a driver of 13q gain. However, overexpression of miR-17-92 alone is not sufficient to transform colorectal adenoma cells into a malignant phenotype.
Project description:The miR-17-92 microRNA cluster is often activated in cancer cells, but the identity of its targets remains largely elusive. Here we examined the effects of activation of the entire miR-17-92 cluster on global protein expression in neuroblastoma cells. In this dataset we deposit global mRNA expression data obtained form primary neuroblastoma tumour cells. This data was used to demonstrate negative correlation between TGFB target gene expression and expression of the miR-17-92 cluster. Expression of different TGFB target genes was correlated to miR-17-92 expression using Spearman's Rank statistics in 40 tumours. A correlation heatmap was calculated to visualize the inverse relation between miR-17-92 expression and TGFB target gene expression.