title: Linking Hematopoietic Differentiation to Co-Expressed Sets of Pluripotency-Associated and Imprinted Genes and to Regulatory microRNA-Transcription Factor Motifs.
abstract: Maintenance of cell pluripotency, differentiation, and reprogramming are regulated by complex gene regulatory networks (GRNs) including monoallelically-expressed imprinted genes. Besides transcriptional control, epigenetic modifications and microRNAs contribute to cellular differentiation. As a model system for studying the capacity of cells to preserve their pluripotency state and the onset of differentiation and subsequent specialization, murine hematopoiesis was used and compared to embryonic stem cells (ESCs) as a control. Using published microarray data, the expression profiles of two sets of genes, pluripotent and imprinted, were compared to a third set of known hematopoietic genes. We found that more than half of the pluripotent and imprinted genes are clearly upregulated in ESCs but subsequently repressed during hematopoiesis. The remaining genes were either upregulated in hematopoietic progenitors or in differentiated blood cells. The three gene sets each consist of three similarly behaving gene groups with similar expression profiles in various lineages of the hematopoietic system as well as in ESCs. To explain this co-regulation behavior, we explored the transcriptional and post-transcriptional mechanisms of pluripotent and imprinted genes and their regulator/target miRNAs in six different hematopoietic lineages. Therewith, lineage-specific transcription factor (TF)-miRNA regulatory networks were generated and their topologies and functional impacts during hematopoiesis were analyzed. This led to the identification of TF-miRNA co-regulatory motifs, for which we validated the contribution to the cellular development of the corresponding lineage in terms of statistical significance and relevance to biological evidence. This analysis also identified key miRNAs and TFs/genes that might play important roles in the derived lineage networks. These molecular associations suggest new aspects of the cellular regulation of the onset of cellular differentiation and during hematopoiesis involving, on one hand, pluripotent genes that were previously not discussed in the context of hematopoiesis and, on the other hand, involve genes that are related to genomic imprinting. These are new links between hematopoiesis and cellular differentiation and the important field of epigenetic modifications.
authors.affiliation: Center for Bioinformatics, Saarland University, Saarbrücken, Germany.|Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, Rostock, Germany.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Hamed
authors.affiliation: Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, Rostock, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Trumm
authors.affiliation: Center for Bioinformatics, Saarland University, Saarbrücken, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Spaniol
authors.affiliation: Center for Bioinformatics, Saarland University, Saarbrücken, Germany.
authors.forename: Riccha
authors.initials: R
authors.lastname: Sethi
authors.affiliation: Kolling Institute of Medical Research, Royal North Shore Hospital, The University of Sydney, St Leonards, NSW, Australia.
authors.forename: Mohammad R
authors.initials: MR
authors.lastname: Irhimeh
authors.affiliation: Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, Rostock, Germany.
authors.forename: Georg
authors.initials: G
authors.lastname: Fuellen
authors.affiliation: Department of Genetics, Saarland University, Saarbrücken, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Paulsen
authors.affiliation: Center for Bioinformatics, Saarland University, Saarbrücken, Germany.
authors.forename: Volkhard
authors.identifier: 0000-0002-2180-9154
authors.initials: V
authors.lastname: Helms
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics*; D019070:Cell Lineage / Q000235:genetics; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D053263:Gene Regulatory Networks; D018392:Genomic Imprinting; D006410:Hematopoiesis / Q000235:genetics; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D059372:Nucleotide Motifs / Q000235:genetics*; D039904:Pluripotent Stem Cells / Q000166:cytology* / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D035683:MicroRNAs; D014157:Transcription Factors