ABSTRACT: We report that macrophage elasticity plays a dominant role in bacterial phagocytosis, release of TNF-alpha, and production of reactive oxygen species. We show that macrophage elasticity is modulated by mechanical factors including substrate rigidity and substrate stretch. Changes in macrophage elasticity are dependent upon the degree of actin polymerization, and mediated in part through small rhoGTPase activity. Moreover, the functional effects of macrophage elasticity are not predicted by gene expression profiles. Murine RAW 267.4 macrophages were separately grown on 2 matrix stiffness levels (1200, 150000 Pascals) for 0, 2, 6, 18 hours with 3 replicate sample experiments per condition. Total RNA extracted from the cells and profiled by microarrays. Keywords: Murine RAW 267.4 macrophage, matrix stiffness, phagocytosis, cell elasticity.
Project description:The tumour microenvironment is a critical element involved in tumour progression and responsiveness to therapies. Using functionalized tunable stiffness hydrogel, mimicking the mechanical properties of healthy and tumour tissues, we explore how the stiffness of the microenvironment can influence cancer cells by generating RNA-seq transcriptional profiles of 4T1 mouse breast cancer cells cultured on soft vs stiff polyacrylamide hydrogels for 24 hours.
Project description:Matrix elasticity influences differentiation of mesenchymal stem cells (MSCs) but it is unclear if these effects are only transient - while the cells reside on the substrate - or if they reflect persistent lineage commitment. In this study, MSCs were continuously culture-expanded in parallel either on polydimethylsiloxane (PDMS) gels of different elasticity or on tissue culture plastic (TCP) to compare impact on replicative senescence, in vitro differentiation, gene expression, and DNA methylation (DNAm) profiles. The maximal number of cumulative population doublings was not affected by matrix elasticity. Differentiation towards adipogenic and osteogenic lineage was increased on soft and rigid biomaterials, respectively - but this propensity was no more evident if cells were transferred to TCP. Global gene expression profiles and DNAm profiles revealed relatively few differences in MSCs cultured on soft or rigid matrices. Furthermore, only moderate DNAm changes were observed upon culture on very soft hydrogels of human platelet lysate. Our results support the notion that matrix elasticity influences cellular differentiation while the cells are organized on the substrate, but it does not have major impact on cell-intrinsic lineage determination, replicative senescence or DNAm patterns. MSCs cultivated either on polydimethylsiloxane (PDMS) gels of different elasticity or on tissue culture plastic (TCP) to compare impact on gene expression profiles.
Project description:We report that macrophage elasticity plays a dominant role in bacterial phagocytosis, release of TNF-alpha, and production of reactive oxygen species. We show that macrophage elasticity is modulated by mechanical factors including substrate rigidity and substrate stretch. Changes in macrophage elasticity are dependent upon the degree of actin polymerization, and mediated in part through small rhoGTPase activity. Moreover, the functional effects of macrophage elasticity are not predicted by gene expression profiles.
Project description:We have compared populations of small (21 to 24-nt) RNAs from Arabidopsis immature flowers of WT, drb2 and drb4 mutants and found that DRB2 and DRB4 are needed for the proper biogenesis of polymerase IV-dependent siRNAs Examination of small RNA populations from three backgournd: Col0 (WT), drb2 and drb4 mutants
Project description:Cells interact with their mechanical environment and respond in consequence. Mechanical cues can have a wide range of influences on cell behaviour, ranging from guidance of differentiation and cell fate to immune activation. The impact of substrate stiffness on primary macrophages - a key player in innate immunity and inflammation - had not been previously studied. We prepared bone marrow-derived macrophage cultures from adult rat hematopoietic stem cells exposed to M-CSF, and cultured these on polyacrylamide substrates of controlled stiffness (ranging from 50 to 0.1 kPa shear modulus, covering the range found in physiological tissues) for 3 days. The RNA from these cells was then extracted and sequenced.
Project description:RNA deep sequencing efforts have revealed abundant expression of small RNAs derived from small nucleolar (sno) RNAs. We employ here spatial RNA deep sequencing to assess the expression of 10-40 nt small RNAs in subcellular compartments of HeLa cells. Total cellular, cytoplasmic, nuclear and nucleolar fractions were isolated, RNA was purified and size-fractionated in a two-step process to yield 10-40 nt RNA fractions. cDNA libraries were constructed and sequenced on a Ion Torrent platform. Vast majority of cellular, cytoplasmic and nuclear small RNA reads were identified as miRNAs. We found the expression of eleven ten miRNAs in the nucleolar preparations using a cut-off rate of 10 reads. Several miRNAs had a greater relative abundance in the nucleolus compared to the other compartments. The nucleolar small RNAs had a unique size distribution consisting of 19-20 and 25 nt RNAs, which were predominantly composed of small snoRNA-derived box C/D RNAs (termed as sdRNA). Sequences from 47 sdRNAs were identified, which mapped both 5M-bM-^@M-^Y and 3M-bM-^@M-^Y ends of the snoRNAs, and retained conserved box C or D motifs. SdRNA reads from SNORD44 comprised 74% of all nucleolar sdRNAs, and were confirmed by Northern blotting as 20 and 25 nt RNAs. This study reveals a rich representation of cell-compartment specific expression of small RNAs and the distinctive unique composition of the nucleolar small RNAs. Examination of small RNAs in cellular subcompartments
Project description:We tested the hypothesis that increasing matrix stiffness on which normal human lung fibroblasts are grown promotes the expression of a fibrogenic cellular transcriptomic program. Keywords: Human lung fibroblast, matrix stiffness, PTGS2, COX-2, Prostaglandin E2 Total RNA extracted from normal human lung fibroblasts from 3 human subjects and separately grown on 5 discrete matrix stiffness conditions: 100, 400, 1600, 6400, 25600 Pascals.
Project description:Intratumor heterogeneity associates with poor patient outcome. Stromal stiffening also accompanies cancer. Whether cancers demonstrate stiffness heterogeneity, and if this is linked to tumor cell heterogeneity remains unclear. We developed a method to measure the stiffness heterogeneity in human breast tumors that quantifies the stromal stiffness each cell experiences and permits visual registration with biomarkers of tumor progression. We present Spatially Transformed Inferential Force Map (STIFMap) which exploits computer vision to precisely automate atomic force microscopy (AFM) indentation combined with a trained convolutional neural network to predict stromal elasticity with micron-resolution using collagen morphological features and ground truth AFM data. We registered high-elasticity regions within human breast tumors colocalizing with markers of mechanical activation and an epithelial-to-mesenchymal transition (EMT). The findings highlight the utility of STIFMaps to assess mechanical heterogeneity of human tumors across length scales from single cells to whole tissues and implicates stromal stiffness in tumor cell heterogeneity.
Project description:Effective innate immunity against many microbial pathogens requires macrophage programs that upregulate phagocytosis and direct antimicrobial pathways, two functions generally assumed to be coordinately regulated. Here the regulation of these key functions was investigated in human blood-derived macrophages. IL-10 induced the phagocytic pathway, including CD209 and scavenger receptors, resulting in phagocytosis of mycobacteria and oxLDL. IL-15 induced the vitamin D-dependent antimicrobial pathway and CD209, yet the cells were less phagocytic. The differential regulation of macrophage functional programs was confirmed by analysis of the spectrum of leprosy lesions: the macrophage phagocytosis pathway was prominent in the clinically progressive, multibacillary form, whereas the vitamin D-dependent antimicrobial pathway predominated in the self-limited form of the disease and in patients undergoing reversal reactions from the multibacillary to the self-limited form. These data indicate that macrophage programs for phagocytosis and antimicrobial responses are distinct and differentially regulated in innate immunity in bacterial infections. Experiment Overall Design: 7 LL lesions, 10 BT lesions, 7 RR lesions