Project description:Microvesicles (MV) are small membrane-bound particles comprised of exosomes and various sized extracellular vesicles. These are released by a number of cell types. Microvesicles have a variety of cellular functions from communication to mediating growth and differentiation. Microvesicles contain proteins and nucleic acids. Previously, we showed that plasma microvesicles contain microRNAs (miRNAs). Based on our previous report, the majority of peripheral blood microvesicles are derived from platelets while mononuclear phagocytes, including macrophages, are the second most abundant population. Here, we characterized macrophage-derived microvesicles and whether they influenced the differentiation of naïve monocytes. We also identified the miRNA content of the macrophage-derived microvesicles. We found that RNA molecules contained in the macrophage-derived microvesicles were transported to target cells, including monocytes, endothelial cells, epithelial cells and fibroblasts. Furthermore, we found that miR-223 was transported to target cells and was functionally active. Based on our observations, we hypothesize that microvesicles bind to and activate target cells. Furthermore, we find that microvesicles induce the differentiation of macrophages. Thus, defining key components of this response may identify novel targets to regulate host defense and inflammation. We used GeneChip microarrays to examine changes in gene expression induced by MV in primary monocyte-derived macrophages (MDM) and in THP1 cells, and compare this to cells treated with GM-CSF and PMA, respectively.
Project description:Microvesicles (MV) are small membrane-bound particles comprised of exosomes and various sized extracellular vesicles. These are released by a number of cell types. Microvesicles have a variety of cellular functions from communication to mediating growth and differentiation. Microvesicles contain proteins and nucleic acids. Previously, we showed that plasma microvesicles contain microRNAs (miRNAs). Based on our previous report, the majority of peripheral blood microvesicles are derived from platelets while mononuclear phagocytes, including macrophages, are the second most abundant population. Here, we characterized macrophage-derived microvesicles and whether they influenced the differentiation of naM-CM-/ve monocytes. We also identified the miRNA content of the macrophage-derived microvesicles. We found that RNA molecules contained in the macrophage-derived microvesicles were transported to target cells, including monocytes, endothelial cells, epithelial cells and fibroblasts. Furthermore, we found that miR-223 was transported to target cells and was functionally active. Based on our observations, we hypothesize that microvesicles bind to and activate target cells. Furthermore, we find that microvesicles induce the differentiation of macrophages. Thus, defining key components of this response may identify novel targets to regulate host defense and inflammation. We used GeneChip microarrays to examine changes in gene expression induced by MV in primary monocyte-derived macrophages (MDM) and in THP1 cells, and compare this to cells treated with GM-CSF and PMA, respectively. All experiments were done in triplicates. Primary monocytes were collected from buffy coats (BC). The freshly isolated monocytes from three donors (Mono1-3) were either treated with GM-CSF or subjected to RNA isolation. Following treatment, MVs were isolated from the GM-CSF-treated macrophage cultures. RNA was isolated from the remaining cells for profiling (GM1-3). The isolated MVs were then used to treat new BC monocytes for 24 h (BC-GMCSF-MV24). A fraction of the new BC monocytes was subjected to RNA extraction for profiling (BC1-3). For THP1 cells, they were treated with either DMSO or PMA to produce MVs. The MVs were collected and the remaining cells lyzed for RNA extraction and profiling (DMSO1-3 and PMA1-3). The collected MVs from the DMSO or PMA-treated THP1 cells were incubated with new THP1 for 24 h and designated DMSO-MV24 or PMA-MV24. We had a total of 24 samples.
Project description:We used a multi-omics approach combining transcriptomics, proteomics and metabolomics to study the impact of over-expression and inhibition of the microRNA miR-223, a pleiotropic regulator of metabolic-related disease, in the RAW monocyte-macrophage cell line. We analyzed the levels of proteins, mRNAs, and metabolites in order to identify genes involved in miR-223 regulation, to determine candidate disease biomarkers and potential therapeutic targets. We observed that both up- and down-regulation of miR-223 induced profound changes in the mRNA, protein and metabolite profiles in RAW cells. Microarray-based transcriptomics evidenced a change in 120 genes that were linked predominantly to histone acetylation, bone remodeling and RNA regulation. In addition, 30 out the 120 genes encoded long noncoding RNAs. The nanoLC-MS/MS revealed that 52 proteins were significantly altered when comparing scramble, pre- and anti-miR-223 treatments. Sixteen out of the mRNAs coding these proteins genes are predicted to have binding sites for miR-223. CARM-1, Ube2g2, Cactin and Ndufaf4 were confirmed to be miR-223 targets by western blotting. Analyses using Gene Ontology annotations evidenced association with cell death, splicing and stability of mRNAs, bone remodeling and cell metabolism. miR-223 alteration changed the expression of CARM-1, Ube2g2, Cactin and Ndufaf4 during osteoclastogenesis and macrophage, indicating that these genes are potential biomarkers of these processes. The most important discriminant metabolites found in the metabolomics study were found to be hydrophilic amino acids, carboxylic acids linked to metabolism and pyrimidine nucleotides, indicating that changes in miR-223 expression alter the metabolic profile of cells, and may affect their apoptotic and proliferative state.
Project description:We used a multi-omics approach to study the impact of miR-223 in the RAW cell line. We evidenced changes linked to cell death, histone acetylation, bone remodeling, RNA regulation. Changes in miR-223 expression altered the metabolic profile of cells including nucleotides. miR-223 impacted NF-kB levels, macrophage differentiation and osteoclastogenesis.
Project description:Acute lung injury (ALI) is characterized by acute respiratory failure in the setting of non-cardiogenic pulmonary edema, causing acute respiratory distress syndrome (ARDS) in patients and contributes significantly to mortality of critically illness. The main goal of our study is to elucidate the role of miRNAs in neutrophil-epithelial communication during pulmonary inflammation and thereby identifying novel targets for therapy of acute lung injury (ALI). In our studies we identified a miR-223-dependent neutrophil-epithelial crosstalk during ALI. Activated neutrophils (PMN) and pulmonary epithelial cells come into a close spatial relationship during ALI. And, since previous studies had indicated the possibility that inflammatory cell-dependent release of miRNA-containing microvesicles could function as a means of exchanging genetic information from a donor to a target cell, we assessed PMN-elicited alterations of pulmonary epithelial miRNA expression in an experimental co-culture setup. This approach provided a selective and extremely robust readout: While other miRNAs were not or only moderately altered in their expression, pulmonary-epithelial-expressed miR-223 was significantly induced after 4 or 6h of co-incubation. Additional in vitro and in vivo studies clearly demonstrate that this increase of epithelial miR-223 is not due to miR-223 transcriptional induction, but instead PMN-dependent and caused by shuttling miR-223 from PMN into pulmonary epithelial cells. To address the functional role of miR-223-dependent neutrophil-epithelial crosstalk during ALI, we exposed mice to ventilator-induced ALI and observed robust induction of pulmonary miR-223 during ALI, while increases of miR-223 were completely abolished after antibody-depletion of PMN. Moreover, studies of alveolar epithelial cells isolated from mice with ALI showed robust increases of miR-223, indicating that miR-223 is shuttled from PMN towards alveolar epithelia during ALI in vivo. Functional studies revealed that gene-targeted mice for miR-223 experience a more severe phenotype during ALI as compared to controls, while their phenotype could be resuscitated by nanoparticle-mediated overexpression of miR-223 in the lungs. In summary, these studies reveal a novel role of miR-223-dependent neutrophil-epithelial crosstalk representing an anti-inflammatory pathway that can be targeted for ALI treatment.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.
Project description:PurposeWe investigated the evidence of recent positive selection in the human phototransduction system at single nucleotide polymorphism (SNP) and gene level.MethodsSNP genotyping data from the International HapMap Project for European, Eastern Asian, and African populations was used to discover differences in haplotype length and allele frequency between these populations. Numeric selection metrics were computed for each SNP and aggregated into gene-level metrics to measure evidence of recent positive selection. The level of recent positive selection in phototransduction genes was evaluated and compared to a set of genes shown previously to be under recent selection, and a set of highly conserved genes as positive and negative controls, respectively.ResultsSix of 20 phototransduction genes evaluated had gene-level selection metrics above the 90th percentile: RGS9, GNB1, RHO, PDE6G, GNAT1, and SLC24A1. The selection signal across these genes was found to be of similar magnitude to the positive control genes and much greater than the negative control genes.ConclusionsThere is evidence for selective pressure in the genes involved in retinal phototransduction, and traces of this selective pressure can be demonstrated using SNP-level and gene-level metrics of allelic variation. We hypothesize that the selective pressure on these genes was related to their role in low light vision and retinal adaptation to ambient light changes. Uncovering the underlying genetics of evolutionary adaptations in phototransduction not only allows greater understanding of vision and visual diseases, but also the development of patient-specific diagnostic and intervention strategies.