Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

RNAi knock-down of MKL1 in human megakaryocytes derived from cord blood or cytapheresis

ABSTRACT: Characterize the genes regulated by MKL1/SRF complex in human megakaryocytes (MKs) derived from cord blood or cytapheresis : Using a knock down approach by small interference of MKL1 in MK progenitors, we observed a decrease in the percentage of cells with actin polymerization after adhesion on various substrates, an increase of mean ploidy level and apoptosis. Furthermore, MKL1 inhibition induced a major defect in pro-platelet formation and MKs migration. These results clearly demonstrate that MKL1 is involved in the cytoskeleton organization and maturation of MKs as well as in platelet formation. The goal of gene profiling was to identify new potential MKL1/SRF targets the expression level of which was down regulated after MKL1 inhibition: Human CD34+ cells isolated from cord blood or cytapheresis were transduced by a control lentivirus (designed as SCR; scramble) or by the lentivirus encoding for shRNA of MKL1 (designed as shMKL1) both containing a GFP expressed under the control of PGK promoter. The cells were than grown in serum free medium supplemented by thrombopoietin leading to a generation of megakaryocytes. At day 9 of culture (80% of MKs), the GFP positive cells were sorted, RNAs were extracted and submitted to hybridization as described in annex protocols. Two lists of genes (one for cord blood samples and one for cytapheresis samples) deregulated after the repression of MKL1 were done comparing the intensity of hybridization between SCR and shMKL1 samples. The common list of genes deregulated in MKs from cord blood and cytapheresis after the repression of MKL1 was than generated.

ORGANISM(S): Homo sapiens

SUBMITTER: Philippe DESSEN

PROVIDER: E-TABM-640 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

MAL/SRF complex is involved in platelet formation and megakaryocyte migration by regulating MYL9 (MLC2) and MMP9.

Gilles Laure L Bluteau Dominique D Boukour Siham S Chang Yunhua Y Zhang Yanyan Y Robert Thomas T Dessen Philippe P Debili Najet N Bernard Olivier A OA Vainchenker William W Raslova Hana H

Blood 20090901 19

Megakaryoblastic leukemia 1 (MAL) is a transcriptional coactivator of serum response factor (SRF). In acute megakaryoblastic leukemia, the MAL gene is translocated and fused with the gene encoding one twenty-two (OTT). Herein, we show that MAL expression increases during the late differentiation steps of neonate and adult human megakaryopoiesis and localized into the nucleus after Rho GTPase activation by adhesion on collagen I or convulxin. MAL knockdown in megakaryocyte progenitors reduced the ...[more]

PMID: 19724058

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Project description:Context : Non Functioning Pituitary Adenomas (NFPAs), although typically benign, may be locally invasive. Few datas are currently available related to the molecular process of invasion in sporadic pituitary adenomas. Markers of invasiveness, important for helping the clinician in the therapeutic strategy particularly in the decision for adjuvant radiotherapy, are currently lacking. Objective: Evaluate if invasive NFPAs display a specific expression profile compared with non invasive tumors. Methods: To address this issue, we selected 40 NFPAs (38 of the gonadotroph type) and classified them as invasive (n=22) or non invasive (n=18) on the basis of MRI and surgical findings. Then we performed pangenomic analysis based on Agilent Human Whole genome Gene Expression oligonucleotide microarray (44k) Expression in order to identify genes differentially expressed between invasive and non invasive NFPA. Experiements are made in dual color with tumor samples labelled in cyanine 5 and a pool of all tumors labelled in cyanine 3.The expressions of some genes identified by microarray screening were confirmed by real-time quantitative RT-PCR. The selection of genes was made on the basis of Ingenuity networks and degree of upregulation between invasive and non invasive tumors. Moreover, some genes of interest already described in the literature were added to the analysis. Results: Prediction class analysis showed that 346 genes discriminated between invasive and non invasive NFPAs (p<0.001); 233 were up- and 113 were down-regulated between the two groups. We then tested On the basis of Ingenuity networks and degree of upregulation between invasive and non invasive tumors, a set of eight genes, including MYO5A, IGFBP5, FLT3, NFE2L1, PTTG, MMP9, NCAM and NR1H3, was tested in quantitative PCR analysis and. Results confirmed those obtained in microarrays results.analysis. At the protein level, Myosin 5A (MYO5A) demonstrated stronger immunostaining in invasive NFPAs compared to non invasive NFPAs. Conclusions: We propose a molecular signature of eight genes of grossly invasive NFPAs as compared with non invasive tumors: The product of one of these genes, MYO5A, may be a useful marker of invasive process in tumoral specimens. The role of these genes in the invasiveness process and as prognostic markers of pituitary adenomas needs to be confirmedinvestigated. Method: Microarray analyses the transcriptome of 22 invasive Non Functional Pituitary Adenomas (NFPAs) and 18 non invasive NFPAs in dual color (each sample labelled in cyanine 5 and a pool of all tumors labelled in cyanine 3).

Dataset Information

RNAi knock-down of MKL1 in human megakaryocytes derived from cord blood or cytapheresis

Publications

MAL/SRF complex is involved in platelet formation and megakaryocyte migration by regulating MYL9 (MLC2) and MMP9.

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