Up-regulation Of miR-145 Research Articles

MicroRNA links obesity and impaired glucose metabolism

MicroRNA links obesity and impaired glucose metabolism

Altered levels of the onco-microRNA 21 and the tumor-supressor microRNAs 143 and 145 in advanced rectal cancer indicate successful neoadjuvant chemoradiotherapy

microRNAs (miRNAs) are small non-coding RNAs with important post-transcriptional regulatory functions. miRNA-21 (miR-21) is upregulated and miR-143 and miR-145 are downregulated in colorectal carcinoma. The aim of our study was to determine if these miRNAs change their expression levels in response to neoadjuvant chemoradiotherapy in advanced rectal cancer. Forty patients with advanced rectal cancer (clinical uT3/T4 Nx) were included. All patients underwent neoadjuvant chemoradiotherapy and surgical resection. Expression of miR-21, -143 and -145 was examined in macrodissected tumor tissue before and after chemoradiotherapy and normal rectal tissue from the resection specimen. RNA was extracted from formalin-fixed and paraffin-embedded tissue by TRIzol method, polyadenylated, reverse transcribed and analyzed by real-time PCR. Therapy response was assessed according to pathological tumor regression. miR-21 was more highly expressed in tumor tissue than in non-tumorous tissue. However, there was a moderately lower expression in post-therapeutic tumor tissue compared to pre-therapeutic tumor tissue. There was a significant upregulation of miR-143 and miR-145 in post-therapeutic tumor tissue compared to pre-therapeutic tumor tissue. According to the predictive and prognostic value of the analyzed miRNAs, a significant correlation between miR-145 expression and tumor regression was seen. Patients with a low intratumoral post-therapeutic expression had significantly more often a worse response to neoadjuvant therapy compared to patients with a high expression of miR145. The present results support the hypothesis that chemoradiotherapy can profoundly alter miRNA expression profiles. miRNAs might play important roles as molecular biomarkers in the prediction of response to treatment and prognosis.

Abstract 1189: MiR-145 inhibits cell proliferation of human lung adenocarcinoma by targeting EGFR and NUDT1

Abstract OBJECTIVE: MicroRNAs (miRNAs) are emerging as important modulators in cellular pathways and appear to play a key role in tumorigenesis. MiR-145 is downregulated in several human malignancies, including lung cancer, but the responsible molecular mechanisms remain unclear. We previously reported that restoration of miR-145 inhibits cancer cell growth in lung adenocarcinoma patients with epidermal growth factor receptor (EGFR) mutation. The present study is undertaken to confirm and extend our previous findings through the identification of target genes for miR-145, and to analyze its biological functions in lung adenocarcinoma. METHODS: Systemic bioinformatic analysis was performed to investigate the potential targets of miR-145 in lung cancer, using publicly available algorithms. The associations of miR-145 and its targeted genes’ expressions were analyzed by mRNA and miRNA microarray profiling in tumor specimens from patients with lung adenocarcinoma. Expressions of miR-145 and its gene targets in human lung adenocarcinoma cells were determined using quantitative RT-PCR. Further validation was performed by Western blot analysis. RESULTS: This study showed that miR-145 targets EGFR and nucleoside diphosphate linked moiety X-type motif 1 (NUDT1 or MTH1) in lung adenocarinoma cells. A significant negative correlation was shown between expressions of miR-145 vs EGFR mRNA (r = -0.72; P = 6.3E-8) and NUDT1 mRNA (r = -0.78; P = 6.3E-8), indicating that miR-145 either directly or indirectly suppresses EGFR and NUDT1 transcriptions. The mRNA expressions of EGFR and NUDT1 were significantly downregulated by 60% and 50% after miR-145 transfection in human lung adenocarcinoma cells (P < 0.05). The enforced expression of miR-145 in three lung adenocarcinoma cell lines (NCI-H1975, HCC827, and NCI-H358) led to a decrease (2.5-, 5-, and 2-fold) of EGFR protein and the abolishing of NUDT1 protein expressions. Our results demonstrated miR-145 in the negative regulation of EGFR and NUDT1 expressions at both mRNA and protein levels. Further analysis showed that miR-145 has the ability to significantly inhibit cell proliferation on transfected lung adenocarcinoma cells over three time points (24, 48, and 72 hours). Proliferation of cells was elevated in a time-dependent fashion after transfection with pEP-miR-Null control (by 3%, 27%, and 58%). Conversely, transfection of miR-145 into the cells resulted in gradual reduction of cell viability (by 22%, 37%, and 34%). Upregulation of miR-145 appeared to be an important gene regulation mechanism for the proliferation of lung adenocarcinoma cells and it correlated strongly with the downregulation of EGFR and NUDT1. DISCUSSION: Our findings provided new insight into the complex regulating pathway comprising miR-145, EGFR, and NUDT1. Understanding miR-145's targets and its regulating pathways may lead to new therapeutic strategies for lung adenocarcinoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1189. doi:10.1158/1538-7445.AM2011-1189

MicroRNA-145 suppresses lung adenocarcinoma-initiating cell proliferation by targeting OCT4

Recent studies demonstrated that microRNA-145 is downregulated in human cancer cells and may function as a tumor suppressor. However, its role in lung cancer tumorigenesis remains unclear. Here, we demonstrated that upregulation of miR-145 reduced the proliferation and invasion as well as the ratio of CD133-positive initiating cells and the tumorosphere growth capacity of the human lung adenocarcinoma A549 cell line. The direct targeting of miR-145 to OCT4 mRNA was predicted by bioinformatic analysis and validated by a luciferase reporter system. We, therefore, confirmed that miR-145 can impair the proliferation of human lung adenocarcinoma-initiating cells by targeting OCT4 and leads to inhibition of lung cancer development.

MiR-145 inhibits cell proliferation of human lung adenocarcinoma by targeting EGFR and NUDT1

MicroRNAs (miRNAs) are emerging as important modulators in cellular pathways and they appear to play a key role in tumorigenesis. MiR-145 is downregulated in several human malignancies, including lung cancer, but the responsible molecular mechanisms remain unclear. We previously reported that restoration of hsa-miR-145 inhibits cancer cell growth in lung adenocarcinoma patients with epidermal growth factor receptor (EGFR) mutation. This study showed that hsa-miR-145 targets EGFR and nucleoside diphosphate linked moiety X-type motif 1 (NUDT1 or MTH1) in lung adenocarinoma cells. The mRNA expressions of EGFR and NUDT1 were significantly downregulated after miR-145 transfection in human lung adenocarcinoma cells. Our results demonstrated miR-145 in the negative regulation of EGFR and NUDT1 expressions at both mRNA and protein levels. Further analysis showed that miR-145 has the ability to inhibit cell proliferation on transfected lung adenocarcinoma cells over three time points (24, 48 and 72 hours). Upregulation of miR-145 appeared to be an important gene regulation mechanism for the proliferation of lung adenocarcinoma cells and it correlated strongly with the downregulation of EGFR and NUDT1. Interestingly, our study revealed that the altered proliferation in lung cancer cells is not accompanied by changes in apoptosis. Our findings provided new insight into the complex regulating pathway comprising of miR-145, EGFR, NUDT1 and other unknown factors which function in cell proliferation but not in apoptosis. Understanding miR-145’s targets and its regulating pathways may lead to new therapeutic strategies for lung adenocarcinoma.

Induction of Micro RNA-143 and 145 In Pre-Treatment CD34+ Cells From Patients with Myelodysplastic Syndrome (MDS) After In Vitroexposure to Lenalidomide Correlates with Clinical Response In Patients Harboring the Del5q Abnormality

AbstractAbstract 123 Background:Lenalidomide is an effective agent in the treatment of MDS particularily in those possesing the deletion 5q (del5q) abnormality. The disease phenotype is partly related to loss of genetic material found in the commonly deleted region (CDR) on the long arm of chromosome 5. Recently implicated genes include miRNA-143, 145 and 146 all of which appear to play a role in innate immune signalling. In this study we examined whether upregulation of miRNAs in pretreatment CD34+ marrow cells from patients with MDS (both del5q and non-del5q) exposed to lenalidomide in vitro predicts for clinical response to the drug. Patients and Methods:In total 31 pre-treatment patient samples were obtained from three North American centres. 11 patients' samples were positive for del5q. All patients had received lenalidomide as per local protocols. Clinical response was defined as per the International Working Group 2000 criteria. Clinical data were available for 26 patients. Hematologic improvement (HI), specifically the eythroid response (HI-E), was examined as the main clinical endpoint. Changes in miR-143, miR-145, miR-146a and miR-146b expression in CD34+ cells after in vitro lenalidomide exposure (10uM for 48 hours) were examined. The CD34- fraction was also analyzed. dCT values were normalized to 5S. A ≥ 1.5 fold change in miRNA expression was considered significant. Results:For the entire cohort mean fold changes in miRNA-143 and 145 post lenalidomide exposure were 1.6 and 1.7, respectively. Little change was seen in miR-146a and miR-146b expression (mean fold change 1.1 and 1.2, respectively). No significant increase was seen in any of the examined miRNA in the CD34 - fraction (Figure 1a). When separated based on del5q status both del5q and non-del5q groups showed a > 1.5 fold increase in expression of miR-143 and miR-145. No significant change in either miR-146a or miR-146b expression was seen (Figure 1b). In the CD34- fraction no significant change was seen in any of the examined miRNAs, irrespective of del5q status (Figure 1c). Examining HI-E, major responses (MR) were seen in 42% of patients (87.5% in the the del 5q cohort (7/8 had a MR) and 22.2% for the non-del5q cohort (4/18 had a MR)). Correlation with clinical response and miRNA expression in the CD34+ fraction is shown in Table I. In the del5q cohort MR was associated with an increase in both miR-143 and miR-145. No correlation with miRNA expression and clinical response was seen in the non del5q cohort. Conclusion:Exposure of CD34+ cells from patients with MDS to lenalidomide results in up regulation of miR-143 and miR-145, irrespective of del5q status. Clinically, upregulation of miR-143 and miR-145 correlates with a HI-E in patients with del5q and may be predictive of response to therapy. Interestingly, the non-responder in the del5q group failed to upregulate miR-145. A similar gene induction pattern was seen in the non-del5q cohort, yet no correlation was seen with clinical outcome. Given that non-del5q patients do not harbor any abnormalities within the CDR of chromosome 5 these miRNAs are unlikely to play a role in their disease phenotype, nor in their response to lenalidomide. [Display omitted] Table I:Correlation between clinical response and miRNA expression.Hematologic Improvement - Erythroid (n)miR143 increased (n)miR145 increased (n)Del5qMR (7)45No MR (1)10Total (8)55Non Del5qMR (4)02No MR (14)610Total (18)612 Disclosures:Nevill:Celgene: Honoraria. Karsan:Celgene: Research Funding.

MicroRNA-24 targeting RNA-binding protein DND1 in tongue squamous cell carcinoma

Deregulations of microRNA have been frequently observed in tongue squamous cell carcinoma (TSCC), but their roles in tumorigenesis are not entirely clear. Here, we reported the up-regulation of miR-24 in TSCC. MiR-24 up-regulation reduced the expression of RNA-binding protein dead end 1 (DND1). Knockdown of miR-24 led to enhanced expression of DND1. The direct targeting of miR-24 to the DND1 mRNA was predicted bioinformatically and confirmed by luciferase reporter gene assays. Furthermore, the miR-24-mediated change in DND1 expression suppressed the expression of cyclin-dependent kinase inhibitor 1B (CDKN1B), and also led to enhanced proliferation and reduced apoptosis in TSCC cells.

Testosterone-induced upregulation of miRNAs in the female mouse liver

Testosterone (T) regulates expression of protein-encoding genes directly through androgen receptor (AR) targeting androgen response element (ARE) in gene promoters or indirectly through non-genotropic mechanisms, but only limited information is available about T effects on expression of gene-regulatory non-coding miRNAs. Here, we investigate the effect of T on miRNA expression profiles in the female mouse liver using miRXplore microarrays and quantitative RT-PCR. T treatment for 3 weeks induced upregulation of the 6 miRNAs miR-22, miR-690, miR-122, let-7A, miR-30D and let-7D, reaching maximal expression at different time-points during T treatment. This upregulation was transient, i.e. it disappeared after T withdrawal for 12 weeks, and it was rather robust since it was not essentially affected by blood-stage infections with Plasmodium chabaudi malaria. In silico analysis revealed an ARE in the miR-122 promoter, while the other 5 miRNAs did not contain any ARE in their 2000 bp promoters. The T-induced upregulation of the 6 miRNAs coincided with a downregulation of some of their target protein-encoding genes, the majority of which did incidentally not contain any ARE in their promoters. T treatment did not affect expression of AR and estrogen receptor β (ERβ), but significantly downregulated the miR-22 target genes ERα and aromatase. This downregulation is presumably not caused by T after its aromatase-mediated conversion to E 2 through ER, but rather by the T-induced upregulation of miR-22. Collectively, our data suggest that T can regulate expression of distinct miRNAs in vivo by both genotropic and non-genotropic mechanisms.

Expression of microRNA-451 in normal and thalassemic erythropoiesis

MicroRNAs (miRNAs) are negative regulators of gene expression that play an important role in hematopoiesis. Thalassemia, a defective globin synthesis leading to precipitate of excess unbound globins in red blood cell precursors, results in defective erythroid precursors and ineffective erythropoiesis. Expression pattern of miR-451, an erythroid-specific miRNA, was analyzed during differentiation of erythroid progenitors derived from normal and thalassemic peripheral blood CD34-positive cells, after 14 days of culture. A biphasic expression with transient up-regulation of miRNA-451 on day 3 of cultures was observed during thalassemic erythroid differentiation. In contrast, the expression pattern of the miR-451 in erythroid cells obtained from the other extravascular hemolytic anemia, i.e., hereditary spherocytosis patients showed no transient up-regulation of miR-451 on day 3 of cultures. Our results suggest that early erythroid progenitors in beta-thalassemia have a dysregulated miRNA-451 expression program, and analysis of microRNA is a relevant approach to determine abnormalities of erythropoiesis.

MiR-24 up-regulation in oral carcinoma: Positive association from clinical and in vitro analysis

MicroRNAs (miRNAs) play important roles in neoplastic process. miR-24 is localized on chromosome 9q22 and 19p13, regions frequently altered in oral squamous cell carcinoma (OSCC). This study showed that miR-24 was up-regulated in OSCC tissues relative to control samples. In addition, the plasma levels of miR-24 in OSCC patients were significantly higher than in control individuals. miR-24 expression was also higher in OSCC cell lines relative to normal oral keratinocytes. Experiments blocking miR-24 and using exogenous miR-24 expression indicated that miR-24 contributes to the growth of OSCC cells and that miR-24 may target p57. This study suggests that miR-24 is involved in the regulation of OSCC growth and that the miR-24's level in plasma may be validatable as a tumor marker for OSCC patients.

Role of microRNA-143 in Fas-mediated apoptosis in human T-cell leukemia Jurkat cells

Treatment of Jurkat T cells with Fas-activating antibody (CH-11) facilitated rapid cell death that was shown to be caspase-dependent apoptosis. The expression of miR-143 was up-regulated during the apoptosis with time. The increased expression of miR-143 emerged from 1 to 2h after the treatment, at which time the caspases-8 and -3 were also activated; and this increase was almost canceled by the pretreatment with an inhibitor of caspase-3 or -8. Furthermore, the transfection of Jurkat cells with mature miR-143 induced a significant growth suppression and enhancement of CH-11-induced apoptosis. On the contrary, an extracellular signal-regulated protein kinase 5 (ERK5), which was determined to be a target of miR-143 in colon cancer DLD-1 cells, was time-dependently down-regulated at the translational level after the treatment. During the apoptosis, the expression level of FasL was maintained and the level of nuclear-Foxo3a was increased in the early phase. These data suggest that the up-regulation of miR-143 could be related to the apoptosis in part by targeting ERK5, which leads to promotion of Foxo3a/FasL positive feedback loop.

MiR-24–mediated downregulation of H2AX suppresses DNA repair in terminally differentiated blood cells

Terminally differentiated cells have a reduced capacity to repair double-stranded breaks, but the molecular mechanism behind this downregulation is unclear. Here we find that miR-24 is upregulated during postmitotic differentiation of hematopoietic cell lines and regulates the histone variant H2AX, a protein that has a key role in the double-stranded break response. We show that the H2AX 3' untranslated region contains conserved miR-24 binding sites that are indeed regulated by miR-24. During terminal differentiation, both H2AX mRNA and protein levels are substantially reduced by miR-24 upregulation in in vitro differentiated cells; similar diminished levels are found in primary human blood cells. miR-24-mediated suppression of H2AX renders cells hypersensitive to gamma-irradiation and genotoxic drugs, a phenotype that is fully rescued by overexpression of miR-24-insensitive H2AX. Therefore, miR-24 upregulation in postreplicative cells reduces H2AX and makes them vulnerable to DNA damage.

MIR-451 and Imatinib mesylate inhibit tumor growth of Glioblastoma stem cells

We examined the microRNA profiles of Glioblastoma stem (CD133+) and non-stem (CD133−) cell populations and found up-regulation of several miRs in the CD133− cells, including miR-451, miR-486, and miR-425, some of which may be involved in regulation of brain differentiation. Transfection of GBM cells with the above miRs inhibited neurosphere formation and transfection with the mature miR-451 dispersed neurospheres, and inhibited GBM cell growth. Furthermore, transfection of miR-451 combined with Imatinib mesylate treatment had a cooperative effect in dispersal of GBM neurospheres. In addition, we identified a target site for SMAD in the promoter region of miR-451 and showed that SMAD3 and 4 activate such a promoter-luciferase construct. Transfection of SMAD in GBM cells inhibited their growth, suggesting that SMAD may drive GBM stem cells to differentiate to CD133− cells through up-regulation of miR-451 and reduces their tumorigenicity. Identification of additional miRs and target genes that regulate GBM stem cells may provide new potential drugs for therapy.

Identification and Characterization of microRNAs modulated by Oxidative Stress

Reactive oxygen species (ROS) play important roles in regulating cellular functions. Some growth factors, such as PDGF and EGF, have been discovered to signal through ROS and activate the MAP kinase cascades to regulate the expression of transcription factors. Several laboratories have found that ROS could directly regulate the binding of transcription factors, like AP‐1, NF‐κB, P21 and P53, to DNA and thus influence the downstream gene expression. MicroRNAs (miRNAs) are a class of regulatory RNAs of approximately 21∼25 nucleotides that posttranscriptionally regulate gene expression by directing mRNA cleavage or translational inhibition. The relationship between oxidative stress and miRNAs has not been clearly defined. Toward this end, we used colo205 as a cell model to explore the effect of oxidative stress on miRNA expression. Cells were exposed to 200 μM H2O2 for 1hr and the expression levels of 225 human miRNAs were determined by quantitative RT‐PCR. H2O2 treatment caused a 5‐fold increase in the level of has‐miR‐145. Similar increase was detected in the level of primary transcript of miR‐145 (pri‐miR‐145). These results indicate that the transcription level of miR‐145 is stimulated by ROS in Colo205. The biological significance of miR‐145 up‐regulation is currently under investigation.

Aberrant expression of microRNA in polycythemia vera

Polycythemia vera is a clonal hematopoietic stem cell disorder in which the JAK2 V617F mutation is observed in >95% of patients, but an as yet unidentified process appears to initiate the clonal expansion of hematopoiesis. Because microRNA regulate hematopoietic differentiation, we hypothesized that dysregulated expression of microRNA may contribute to the pathophysiology of polycythemia vera. We performed gene expression profiling in five patients with polycythemia vera and in five controls using CombiMatrix MicroRNA CustomArray. ANOVA identified deregulated microRNA in polycythemia vera, and their expression was studied in a larger set of samples by quantitative reverse transcriptase polymerase chain reaction. The expression of these microRNA was also analyzed in other myeloproliferative disorders. We observed down-regulation of let-7a and up-regulation of miR-182 in polycythemia vera granulocytes, up-regulation of miR-143, miR-145 and miR-223 in polycythemia vera mononuclear cells, up-regulation of miR-26b in polycythemia vera platelets, and down-regulation of miR-30b, miR-30c and miR-150 in polycythemia vera reticulocytes. JAK2 V617F frequency was positively correlated with miR-143 expression and inversely correlated with let-7a, miR-30c, miR-342 and miR-150. Transcript level of predicted target genes was determined, and overexpression of IRAK2 was detected in all granulocytes from patients with myeloproliferative disorders and in polycythemia vera reticulocytes. Abnormally high HMGA2 microRNA was found in myelofibrosis granulocytes. Our study demonstrates that peripheral blood cells from patients with polycythemia vera have microRNA signatures distinct from those of controls. Our findings of aberrant microRNA expression underline the complexity of the molecular basis of polycythemia vera.

Differential Expression of miRNAs in Polycythemia Vera Peripheral Blood Cells.

Polycythemia vera (PV) is a clonal myeloproliferative disorder caused by somatic mutation of a hematopoietic multipotent cell. PV hematopoiesis is characterized by an accumulation of phenotypically normal erythrocytes with overproduction of leukocytes and platelets. A somatic JAK2 V617F point mutation occurs in the majority (>95%) of PV patients. However, this mutation is also found in ∼50% of patients with either essential thrombocythemia (ET) or idiopathic myelofibrosis (MF). The non-specificity of this mutation, the presence of JAK2 V617F-negative PV patients, JAK2 V617F-negative and positive relatives, and evidence of both JAK2 V617F-negative and positive PV clones demonstrate that the JAK2 V617F mutation is not the initial and sole somatic event for the pathogenesis of PV. MicroRNAs (miRNAs) have been shown to be important regulators of hematopoiesis. To identify deregulated miRNAs involved in PV pathogenesis, we studied gene expression of miRNAs of in vitro expanded erythroid progenitors (EPs), peripheral blood mononuclear cells (MNCs), granulocytes, reticulocytes, and platelets from PV patients and healthy controls. Initially, we performed gene expression profiling in 5 PV patients and 5 control cells using CombiMatrix MicroRNA CustomArray with 326 probes. The array data were analyzed by Genesis software to determine differentially expressed miRNAs in PV. These miRNAs were tested in a larger set of samples (n=18) by qRT-PCR and their expression was correlated to the JAK2 V617F mutational level. Hierarchical clustering analysis defined miRNA expression profiles of particular cell lineage for normal and PV cells. Further, ANOVA identified 31 miRNAs differently (P<0.05) expressed in at least some PV lineage cells. Of these miRNAs, we confirmed downregulation of miR-150 in expanded EPs of all stages of maturation, downregulation of let7a and upregulation of miR-182 in PV granulocytes; upregulation of miR-143, miR-145 and miR-223 in PV MNCs; and down-regulation of miR-30b, miR-30c and miR-150 in PV reticulocytes by qRT-PCR. Correlation analysis of miRNA expression with JAK2 V617F mutational level showed a positive correlation of miR-143 (r=0.68) and a negative correlation of let7a (r =−0.63), miR-30c (r=−0.74), miR-342 (r=−0.66) and miR-150 (r=−0.89). To validate PV specificity, we compared expression levels of these miRNAs to other MPD disorders (MF and ET) in which the JAK2 V617F mutation occurs. Putative miRNA targets were predicted by TargetScan 4.0 and PicTar software, and transcript levels of selected target genes are being analyzed to determine their potential deregulation at the mRNA level. Downregulated miR-150 is predicted to the target MYB oncogene that plays an important role in erythropoiesis by maintaining proliferation at the early stages. The most potential target of let7a is HGMA2, whose aberrant expression may contribute to clonal hematopoiesis in PNH. The verification of these predictions is in process by use of miRNA inhibitors, protein levels, and functional studies of the progenitors. Our study demonstrates that the specific signatures of miRNAs define particular peripheral blood cell lineages. Furthermore, the deregulated miRNAs, whose expressions correlate with the JAK2 mutational level, may be associated with the PV phenotype. Understanding the role of deregulated miRNAs in PV should provide insight into the pathogenesis of PV and may lead to novel therapeutic strategies.

Regulated expression of microRNAs in normal and polycythemia vera erythropoiesis

Polycythemia vera (PV) is a myeloproliferative disorder, arising from the acquired mutation(s) of a hematopoietic stem cell. The JAK2 V617F somatic mutation is found in most PV patients; however, it is not the disease-initiating mutation. Because microRNAs (miRNAs) play a regulatory role in hematopoiesis, we studied miRNA expressions in PV and normal erythropoiesis. Peripheral blood mononuclear cells were cultured in a three-phase liquid system resulting in synchronized expansion of erythroid progenitors. Using gene-expression profiling by CombiMatrix MicroRNArray, we searched for PV-specific changes at days 1, 14, and 21. Twelve miRNA candidates were then reevaluated by quantitative real-time polymerase chain reaction in a larger number of samples obtained from progenitors at the same stage of differentiation. A significant difference in miR-150 expression was found in PV. In normal erythropoiesis, three expression patterns of miRNAs were observed: progressive downregulation of miR-150, miR-155, miR-221, miR-222; upregulation of miR-451, miR-16 at late stages of erythropoiesis; and biphasic regulation of miR-339, miR-378. The miR-451 appears to be erythroid-specific. We identified the miRNAs with regulated expression in erythropoiesis; one appeared to be PV-specific. Their miRNA expression levels define early, intermediate, and late stages of erythroid differentiation. The validity of our findings was confirmed in nonexpanded peripheral blood cells.

Maladie de Gaucher de type 1 chez l’adulte: Prise en charge nutritionnelle lors de la mise en place d’un traitement par miglustat

Resistin is associated with insulin resistance, and determining its developmental and molecular mechanisms may help the development of novel treatments. MicroRNAs (miRNAs) are involved in many physiological and pathological processes as negative regulators. However, it remains unclear whether miRNAs play a role in resistin-induced insulin resistance. We performed mouse liver miRNA microarrays to analyze the differences in expression between resistin-treated and control mice. Resistin upregulated miR-145 both in vivo and in vitro. Therefore, we aimed to study whether miR-145 played a role in resistin-induced insulin resistance.We transfected HepG2 cells, and used miR-145 mimics and inhibitors to assess the role of miR-145 in resistin-induced insulin resistance. The overexpression of miR-145 inhibited glucose uptake in HepG2 cells, diminished the phosphorylation of Akt and IRS-1, and induced insulin resistance in hepatocytes. Next, a study of transcriptional regulation revealed that p65 was essential for the upregulation of miR-145 by resistin, and chromatin immunoprecipitation (ChIP) confirmed that p65 could bind to the promoter region of miR-145.miR-145 plays a role in the development of resistin-induced insulin resistance via the p65 pathway.