Project description:Patients with sickle cell anemia (SCA) show higher levels of circulating pro-inflammatory cytokines and endothelial activation markers compared to healthy peers and altered blood transcriptome profiles. However, the characterization of the whole-blood transcriptome profile in response to exercise has not been evaluated in children with SCA. Twenty-three children/adolescents with SCA (10-19 years old) and 17 healthy controls (10-22 years old) performed eight 2-min bouts of cycle ergometry interspersed with 1-min rest intervals (50% or 70% of the peak workload achieved during the cardiopulmonary exercise test). Whole-blood transcriptome profile (RNA-seq) was performed before and after the exercise protocol. Following exercise, gene pathways associated with innate immunity were altered in both children with SCA and controls. Our results shed light on the common and different immune responses to acute exercise at the molecular level in children with SCA and healthy controls.
Project description:We hypothesized that miRNA regulation may be invloved in hydroxyurea-mediated fetal hemoglobin induction. Microarray analysis was utilized as an initial screening tool to determine differential miRNA expression in CD71+ erythroid cells comparing cells from control individuals without sickle cell anemia to patients with sickle cell anemia prior to treatment with hydroxyurea and patients receiving the maximum tolerated dose (MTD) of hydroxurea. CD71+ cells were isolated from whole blood of control individuals (n=2), pediatric patients without hydroxyurea treatment (n=3) and pediatric patients at hydroxyurea MTD (n=3). All 8 samples were analyzed for miRNA expression.
Project description:We hypothesized that miRNA regulation may be invloved in hydroxyurea-mediated fetal hemoglobin induction. Microarray analysis was utilized as an initial screening tool to determine differential miRNA expression in CD71+ erythroid cells comparing cells from control individuals without sickle cell anemia to patients with sickle cell anemia prior to treatment with hydroxyurea and patients receiving the maximum tolerated dose (MTD) of hydroxurea.
Project description:Genetic differences in endothelial biology could underlie development of phenotypic heterogeneity amongst individuals afflicted with vascular diseases. We obtained BOEC (blood outgrowth endothelial cells) from 20 subjects with sickle cell anemia (age 4-19) shown to be either at-risk (n=11) or not-at-risk (n=9) for ischemic stroke due to, respectively, having or not having occlusive disease at the Circle of Willis (CoW). Gene expression profiling identified no significant single gene differences between the two groups, as expected. However, analysis of Biological Systems Scores, using gene sets that were pre-determined to survey each of nine biological systems, showed that only changes in inflammation signaling are characteristic of the at-risk subjects, as supported by multiple statistical approaches Experiment Overall Design: We obtained BOEC (blood outgrowth endothelial cells) from 20 subjects with sickle cell anemia (age 4-19) shown to be either at-risk (n=11) or not-at-risk (n=9) for ischemic stroke due to, respectively, having or not having occlusive disease at the Circle of Willis (CoW). To allow power calculations to be done, we performed microarray analysis on BOEC from 27 normal subjects of diverse ages. Gene expression profilings were obtained by using Affymetrix U133A chips
Project description:To analyze expression of inflammatory cytokines in Exhaled Breath Condensates from pediatric patients with sickle cell disease, asthma, sickle cell disease and asthma, and controls
Project description:Transcriptional changes in compensatory erythropoiesis in sickle cell anemia (SCA) and their disease modulation are unclear. We detected 1226 differentially expressed genes in hemoglobin SS reticulocytes compared to non-anemic hemoglobin AA controls. Assessing developmental expression changes in hemoglobin AA erythroblasts for these genes suggests heightened terminal differentiation in early erythroblasts in SCA that diminishes toward the polychromatic to orthochromatic stage transition. Comparison of reticulocyte gene expression changes in SCA with that in Chuvash erythrocytosis, a non-anemic disorder of increased erythropoiesis due to constitutive activation of hypoxia inducible factors, identified 453 SCA-specific changes attributable to compensatory erythropoiesis. Peripheral blood mononuclear cells (PBMCs) in SCA contain elevated proportions of erythroid progenitors due to heightened erythropoiesis. Deconvolution analysis in PBMCs from 131 SCA patients detected 54 genes whose erythroid expression correlated with erythropoiesis efficiency, which were enriched with SCA-specific changes (OR=2.9, P=0.00063) and annotation keywords of “ubiquitin-dependent protein catabolic process” and “protein ubiquitination” (OR=4.1, P=9.6×10-5). An erythroid expression quantitative trait locus of one of these genes, LNX2 encoding an E3 ubiquitin ligase, associated with severe pain episodes in 774 SCA patients (OR=1.7, P=3.9×10-5). Thus, erythroid gene transcription responds to unique conditions within SCA erythroblasts and these changes potentially correspond to vaso-occlusive manifestations.
Project description:Ischemic Stroke (IS) is one of the most impairing complications of sickle cell anemia (SCA), responsible for 20% of mortality in patients. Rheological alterations, adhesive properties of sickle reticulocytes, leukocyte adhesion, inflammation and endothelial dysfunction are related to the vasculopathy observed prior to ischemic events. The role of the vascular endothelium in this complex cascade of mechanisms is emphasized, as well as in the process of ischemia-induced repair and neovascularization. The aim of the present study was to perform a comparative transcriptomic analysis of endothelial colony-forming cells (ECFCs) from SCA patients with and without IS. Next, to gain further insights of the biological relevance of differentially expressed genes (DEGs), functional enrichment analysis, protein-protein interaction network (PPI) construction and in silico prediction of regulatory factors were performed. Among the 2,469 DEGs, genes related to cell proliferation (AKT1, E2F1, CDCA5, EGFL7), migration (AKT1, HRAS), angiogenesis (AKT1, EGFL7) and defense response pathways (HRAS, IRF3, TGFB1), important endothelial cell molecular mechanisms in post ischemia repair were identified. Despite the severity of IS in SCA, widely accepted molecular targets are still lacking, especially related to stroke outcome. Thus, these exploratory results may contribute to a better understanding of the role of endothelial cells in SCA ischemic stroke recovery, and promote new insights to further studies on therapeutic strategies for this severe complication.
Project description:Compromised renal function after renal allograft transplantation often results in anemia in the recipient. Molecular mechanisms leading to anemia during acute rejection are not fully understood; inadequate erythropoietin production and iron deficiency have been reported to be the main contributors. To increase our understanding of the molecular events underlying anemia in acute rejection, we analyzed the gene expression profiles of peripheral blood lymphocytes (PBL) from four pediatric renal allograft recipients with acute rejection and concurrent anemia, using DNA microarrays containing 9000 human cDNA clones (representing 7469 unique genes). In these anemic rejecting patients, an 'erythropoiesis cluster' of 11 down-regulated genes was identified, involved in hemoglobin transcription and synthesis, iron and folate binding and transport. Additionally, some alloimmune response genes were simultaneously down-regulated. An independent data set of 36 PBL samples, some with acute rejection and some with concurrence of acute rejection and anemia, were analyzed to support a possible association between acute rejection and anemia. In conclusion, analysis using DNA microarrays has identified a cluster of genes related to hemoglobin synthesis and/or erythropoeisis that was altered in kidneys with renal allograft rejection compared with normal kidneys. The possible relationship between alterations in the expression of this cluster, reduced renal function, the alloimmune process itself, and other influences on the renal transplant awaits further analysis.