Project description:With broad high-throughput evaluation of microRNA expression across the spectrum of colon cancer stages, we identidied a microRNA signature that is associated with more aggressive disease microRNA was extracted from FFPE colon tissues for microRNA array analysis
Project description:To discover a panel of mi(cro)RNAs that accurately differentiate between high-risk IPMN tissue (from pathologically-confirmed invasive or high-grade IPMN cases) and low-risk IPMN tissue (from pathologically-confirmed low-or moderate-grade IPMN cases). In a discovery phase, genome-wide miRNA expression profiling was performed on 28 surgically-resected, pathologically-confirmed IPMNs (19 high-risk, 9 low-risk) using Taqman Low Density Arrays. A validation phase was performed in 21 independent IPMNs (13 high-risk, 8 low-risk). We also explored genes regulated by the identified miRNAs by integrating microarray expression data from 23 IPMNs.
Project description:MicroRNAs (miRNAs) are non-coding RNAs that play a fundamental role in regulation of gene expression affecting differentiation and development. In particular, miRNAs have been described to regulate genes important for pancreatic development and islet function. The aim of this work was to determine the miRNA expression signature in human pancreatic alpha and beta cells. miRNA stability to fixation allowed the study of microRNA in pure populations of human alpha and beta cells sorted by FACS after intracellular staining with glucagon and insulin, respectively. The determination of the specific group of miRNAs expressed in the human pancreatic alpha and beta cells may further the understanding of gene expression regulation of the islet differentiation process. The alpha and beta cells come from 6 different preparations of human pancreatic islets from donors. In this study we define expression profiles of a total of 665 miRNAs for pancreatic alpha and beta cells. For this purpose, cells were fixed with paraformaldehyde, 7AAD was applied to exclude dead cells. Then, cells were sorted after intracellular staining with C peptide to detect beta cells and glucagon to detect alpha cells. After sorting, we confirmed enriched beta cells have a purity of on average over 98%. Enriched alpha cells have a purity of on average over 98%. To determine the miRNA expression profiles, we used human miRNA TLDAs version 2. For each sample card A and card B were run after cDNA synthesis and 12 cycles of preamplification according to the manufacturer protocol. Each TLDA card A contains 1 probe for the endogenous control RNU48 while each TLDA card B contains 4 replicates of the RNU48 probe. Analysis of these controls allows calculating the intra- and inter-assay variation. Quantitative values (RQ) were calculated measuring the ddCt between the Ct values of each miRNA and the Ct value of the small nucleolar RNU48 RNA comparing the target sample and the control sample.
Project description:Endogenous damage associated molecular pattern molecules (DAMPs) released from necrotic, damaged or stressed cells are associated with an inflammatory response. Whether the microRNA expression signature of this response is different from that of a PAMP-stimulated inflammatory response is unknown. We report here that miR-34c and miR-214 are significantly expressed in fresh human PBMCs exposed to DAMPcontaining freeze-thaw lysates, or to conditioned media from serum-starved and glucose-deprived cells (p<6x10-4 and p<3.7x10-3), respectively. Interestingly, only miR-34c expression was differentially expressed in PBMCs exposed to freeze-thaw lysates or conditioned media from HMGB1+/+ mouse embryonic fibroblast (MEF) cells, when compared to cultures exposed to lysates or conditioned media from HMGB1-/- MEFs. miR-155 expression in these cultures was negligible, but was significantly higher in PBMCs stimulated with LPS or most other TLR ligands, making it the prototypic PAMPmiR. Exposure to a damaged human colorectal carcinoma cell line lysate (HCT116) similarly resulted in increased miR-34c and miR-214 levels. When PBMCs were pre-transfected with anti-miR-34c and then exposed to lysate, expression levels of IKKgamma mRNA, a putative target of miR-34c, increased, while protein levels of IKKgamma in cultures transfected with a pre-miR-34c were abrogated. Levels of miR-34c expression (as well as pro-inflammatory cytokines, IL-1beta and TNFalpha) decreased when PBMC cultures were briefly pre-incubated with the K+ channel (inflammasome) inhibitor, glybenclamide, suggesting that miR-34c is involved in the inflammasome pathway in response to DAMPs. Our findings suggest that a specific microRNA expression signature is associated with the inflammatory response to damaged/injured cells and carries implications for many acute and chronic inflammatory disorders. Human PBMC (peripheral blood mononuclear cells) were exposed to 4 conditions for 48 hours. In the first condition, PBMCs were exposed to conditioned media from serum-starved and glucose-deprived and heat shocked HMGB1-/- MEF cells (mouse embryonic fibroblast cells). In the second condition, PBMCs were exposed to conditioned media from serum-starved and glucose-deprived and heat shocked HMGB1+/+ MEF cells (mouse embryonic fibroblast cells). In the third condition, PBMCs were exposed to LPS (Lipopolysaccharide). In the fourth condition, the PBMCs where left untreated. Four biological repeats were done for each condition for a total of 16 samples.
Project description:To identify any differentially expressed miRNAs in the CD4+ T cells of lupus. MicroRNAs (miRNAs) have been implicated as fine-tuning regulators controlling diverse biological processes at the level of posttranscriptional repression. Dysregulation of miRNAs has been described in various disease states, including human lupus. By using high-throughput microRNA profiling analysis, we identified that two miRNAs (miR-21 and miR-148a) overexpressed in CD4+ T cells from both lupus patients and lupus-prone MRL/lpr mice,which promote cell hypomethylation by repressing DNA methyltransferase 1 (DNMT1) expression. We isolated the splenic CD4+ T cells and B cells from MRL/lpr mice at 5 and 16 weeks of age.Cells were collected and total RNA was extracted for the TaqMan® Low Density Assay v2.0 Normalization was performed with snoRNA202, reference snRNAs for mouse.Comparative real-time PCR was performed in triplicate, including no-template.controls. Relative expression was calculated with the comparative cycle threshold method.
Project description:Osteosarcoma is the most common bone tumor in children, adolescents, and young adults. In contrast to other childhood malignancies, no biomarkers have been consistently identified as predictors of outcome. This study was conducted to assess the microRNAs (miRs) expression signatures in pre-treatment osteosarcoma specimens and correlate with outcome to identify biomarkers for disease relapse The cohort consisted of 25 patients of 70% Mexican-American ethnicity. High-throughput RT-qPCR approach was used to generate quantitative expression of 754 miRs in the human genome.
Project description:Hematopoietic stem cells (HSCs) can regenerate the entire hematopoietic system in vivo, providing the most relevant criteria to measure candidate HSCs derived from human embryonic stem cell (hESC) or induced pluripotent stem cell (hiPSC) sources. Here, we show that unlike primitive hematopoietic cells derived from hESCs, phenotypically identical cells derived from hiPSC are more permissive to graft the bone marrow of xenotransplantation recipients. Despite establishment of bone marrow graft, hiPSC-derived cells fail to demonstrate hematopoietic differentiation in vivo. However, once removed from recipient bone marrow, hiPSC-derived grafts were capable of in vitro multilineage hematopoietic differentiation, indicating that xenograft imparts a restriction to in vivo hematopoietic progression. This failure to regenerate multilineage hematopoiesis in vivo was attributed to the inability to downregulate key microRNAs involved in hematopoiesis. Based on these analyses, our study indicates that hiPSCs provide a beneficial source of pluripotent stem cell-derived hematopoietic cells for transplantation compared with hESCs. Since use of the human-mouse xenograft models prevents detection of putative hiPSC-derived HSCs, we suggest that new preclinical models should be explored to fully evaluate cells generated from hiPSC sources. Human pluripotent stem cell-derived hematopoietic cells were isolated and qPCR-based microRNA profiling was performed.
Project description:microRNA expression signatures can differentiate normal and breast cancer tissues and can define specific clinico-pathological phenotypes in breast tumors. In order to further evaluate the microRNA expression profile in breast cancer, we analyzed the expression of 667 microRNAs in 29 tumors and 21 adjacent normal tissues using TaqMan Low-density arrays. 130 miRNAs showed significant differential expression (adjusted P value=0.05, Fold Change=2) in breast tumors compared to the normal adjacent tissue. Importantly, the role of 43 of these microRNAs has not been previously reported in breast cancer, including several evolutionary conserved microRNA*, showing similar expression rates to that of their corresponding leading strand. The procedure begins with the retro-transcription of 70ng of total RNA with stem-loop primers to obtain a cDNA template. A pre-amplification step was included in order to increase the concentration of the original material and to detect microRNAs that are expressed at low levels. The pre-amplified product was loaded into the TaqManM-BM-. Low Density Arrays and amplification signal detection was carried out using the 7900 FAST real time thermal cycler (ABI). A total of 29 tumor and 21 normal samples (two pools: one containing five samples, other containing 12 samples, plus 4 independent normal samples) were analyzed. 23 tumors and the two normal pools were processed by triplicate, representing 82% of the total samples.
Project description:Platelets contain abundant miRNAs, however, the biogenesis pathway of miRNAs in anucleate platelets is unclear. Platelet-rich plasma was diluted in washing buffer and the platelet suspension was centrifuged to isolated pure platelets.Finally, platelets were recovered in suspension buffer at the concentration of 4–5×10^8 platelets/ml. Aliquots of the platelet suspensions were activated in the presence of 2.5 mM CaCl2 with 0ng/ml or 1 ng/ml thrombopoietin (TPO)
Project description:MicroRNAs (miRNAs) are non-coding RNAs that play a fundamental role in regulation of gene expression affecting differentiation and development. In particular, miRNAs have been described to regulate genes important for pancreatic development and islet function. The aim of this study was to determine the miRNA expression signature during human pancreas development. We identified 212 miRNAs that were expressed throughout different gestational ages. From those, 4 miRNAs increased (group I), 35 miRNAs decreased (group II), during pancreatic development. The expression of the remaining 173 miRNAs was relatively constant throughout all assessed gestational ages. The determination of the specific group of miRNAs expressed in the human developing pancreas may further the understanding of gene expression regulation during this important process. In this study we define expression profiles of a total of 352 miRNAs for different stages of the pancreas development. Each TLDA card contains 2 endogenous controls which are present in 8 replicates each. Analysis of these controls allows calculating the intra- and inter-assay variation. Quantitative values (RQ) were calculated measuring the dCt between the Ct values of each miRNA and the Ct value of the small nucleolar RNU48 RNA.