Project description:Chronic lymphocytic leukemia (CLL) stereotyped subsets #6 and #8 include cases expressing unmutated B cell receptor immunoglobulin (BcR IG) (U-CLL). Yet, subset #6 (IGHV1-69/IGKV3-20) is less aggressive compared to subset #8 (IGHV4-39/IGKV1(D)-39) which has the highest risk for Richter’s transformation among all CLL. The underlying reasons for this divergent clinical behavior are not fully elucidated. To gain insight into this issue, here we focused on their gene expression profiling and performed RNA-seq.
Project description:Chronic lymphocytic leukemia (CLL) stereotyped subsets #6 and #8 include cases expressing unmutated B cell receptor immunoglobulin (BcR IG) (U-CLL). Yet, subset #6 (IGHV1-69/IGKV3-20) is less aggressive compared to subset #8 (IGHV4-39/IGKV1(D)-39) which has the highest risk for Richter’s transformation among all CLL. The underlying reasons for this divergent clinical behavior are not fully elucidated. To gain insight into this issue, here we focused on epigenomic signatures and their links with gene expression, particularly investigating genome-wide DNA methylation profiles in subsets #6 and #8 as well as other U-CLL cases not expressing stereotyped BcR IG using the Illumina 450k methylation arrays. Additionally we analysed the methylation profiles of naive and memory B cell subsets from healthy donors and compared them with those of the CLL cases.
Project description:Transcription profiles were compared according to the gender of CLL patients as well as according to the sensitivity of CLL cells to undergo or not DNA damage-induced apoptosis in vitro.
Project description:The purpose of the experiment was to determine whole transcriptome changes after spinal cord injury (SCI) to understand how photobiomodulation promotes neuroprotection and functional recovery. SCI was performed at the thoracic (T) level T8, by crushing the dorsal columns using a calibrated watchmaker's forceps. Animals were then treated with photobiomodulation (PBM; 660nm wavelength) or sham control light, within 15 minutes of the injury. PBM or sham-treatment was treatment directed at the lesion site for 1 minute duration every 24hr for the first 3 days. Animals were then killed, tissues harvested and the RNA was extracted using RNEasy lipid tissue mini kit (Qiagen) according to the manufacture's instructions. Whole genome sequencing was outsourced to Qiagen RNA Sequencing Services (Germany).Library preparation was performed using the QIAseq Stranded Total RNA Library Kit with QIAseq FastSelect rRNA and globin depletion. QIAseq FastSelect rRNA HMR was used to reduce the amount of unwanted RNA species. After first and second strand synthesis, the cDNA was end-repaired and 3’ adenylated. Sequencing adapters were ligated to the overhangs. Adapted molecules were enriched using 16 cycles of PCR and purified by a bead-based cleanup. Library preparation was quality controlled using capillary electrophoresis (High Sensitivity Tape D1000) and high-quality libraries were pooled based on equimolar concentrations. The library pool(s) were quantified using qPCR and optimal concentration of the library pool used to generate the clusters on the surface of a flowcell before sequencing on a NovaSeq (Illumina Inc., Madison, USA) instrument (2x75, 2x10) according to the manufacturer instructions (Illumina Inc.). Raw data was de-multiplexed and FASTQ files for each sample were generated using the bcl2fastq software v2.20.0.422 (Illumina inc.).
Project description:Chronic lymphocytic leukaemia (CLL) is renowned for its variable clinical course and response to therapy, suggesting a role for precision medicine. However, the molecular basis of CLL variability remains incompletely understood. Recent developments in data independent acquisition (DIA) -MS technologies, such as SWATH (Sequential Windowed Acquisition of all THeoretical fragments), provide an opportunity to study the pathophysiology of CLL at the proteome level. This report describes the sample replication and data handling requirements for SWATH-MS analysis of clinical samples. A CLL-specific spectral library compromising over 1,500,000 spectra with digital information for over 150,000 peptides has been generated to enable the quantification of up to 7736 proteins. To assess the reproducibility of the assay, SWATH-MS analysis was performed on 6 cryopreserved CLL patient samples, incorporating biological (IGHV mutational status), sample preparation and MS technical replicates. Quantitative information was obtained for 5169 proteins (<1% FDR) across 54 SWATH-MS acquisitions. These analyses showed that SWATH-MS is a highly reproducible technique. However, replicate sample preparations on different days was identified as the main source of variation. To overcome the effect of variation between sample preparation batches, different computational approaches for batch correction were tested. All approaches successfully removed technical variability whilst retaining proteomic differences between clinical subgroups. Functional enrichment analysis of proteins associated to IGHV mutational status highlighted the importance of metabolic remodelling in the biology of CLL and overlapped significantly with previous studies based on gene expression profiling. Finally, an approach to perform statistical power analysis in proteomics studies was developed. This approach could be used to drive the design of future CLL SWATH-MS studies. These fundamental requirements for DIA approaches should be widely applicable to other clinical proteomics studies.
Project description:Three different cell populations (6 healthy B-lymphocytes, 6 leukemic CLL B-lymphocyte of indolent form and 5 leukemic CLL B-lymphocyte of aggressive form) were stimulated in vitro with an anti-IgM antibody, activating the B-cell receptor (BCR). We analyzed the gene expression at 4 time points (60, 90, 210 and 390 minutes). Each gene expression measurement is performed both in stimulated cells and in control unstimulated cells. For one aggressive CLL case, we silenced expression of DUSP1 by transfecting DUSP1-specific RNAi and, as a control, transfected cells with a non-targeting RNAi. We then stimulated the BCR of these cells and analyzed the gene expression at the same time points in stimulated cells and in control unstimulated cells. B-cells were negatively selected from healthy donors and previously untreated CLL patients. BCR stimulated and unstimulated control B-cells were treated at four time points after stimulation for total RNA extraction and hybridization on Affymetrix microarrays.
Project description:Total RNA-seq was performed on HeLa cells to investigate transcriptomic changes associated with physiological protein condensates. rRNA was depleted using NEBNext rRNA Depletion Kit. Strand-specific libraries were prepared using QIAseq FastSelect and NEBNext Ultra II Directional RNA Library Prep Kit. Sequencing was performed on Illumina NovaSeq X Plus with 2x150 paired-end configuration. Reads were trimmed with Trimmomatic, mapped to human reference genome (ENSEMBL) using STAR, and gene counts generated with featureCounts.
Project description:Chronic lymphocytic leukemic B cells (CLL) reside in close contact with activated endothelial cells (EC) in infiltrated tissues. Here, we investigated the interactions between EC and CLL cells, highlighting molecular networks involved in this cellular crosstalk. We co-cultured purified CLL cells on HUVEC monolayer (HC) or in medium alone. We found that EC protected CLL from spontaneous apoptosis. A 2.2-fold increase in relative viability in IGHV mutated CLL and a 6.1-fold increase in IGHV unmutated CLL was detected in co-culture. Moreover, the endothelial cell layer decreased the in vitro sensitivity of CLL cells to Fludarabine-induced apoptosis. Physical contact with EC is essential for protection to apoptosis. The insertion of a microporous membrane or blocking adhesion with anti-CD106 and anti-CD18 antibodies determined the complete abrogation of apoptosis protection. On the other hand, a reduction of apoptosis was measured in CLL cells cultured with conditioned medium collected from HC, implying that survival is partially mediated by soluble factors. Overall 1944 genes were modulated in CLL by co-culture. The EC contact seem to determine on CLL a kind of microenvironmental-driven angiogenic switch, improve the secretion of cytokines regulating tissue elements such as stromal cells and macrophages and also increase anti-apoptotic molecules. Our study support the line of evidence indicating endothelial cells as a major player in the CLL-infiltrated microenvironments are able to create a vicious cycle of cooperation that strongly sustains leukemic cell survival, protects CLL from drug-induced apoptosis and widely modifies CLL phenotype. Large-scale gene expression profiling (GEP) was performed on total RNA extracted from purified CD19+ cells isolated from 9 individual CLL patients which were separated in 3 experimental subsets: (i) freshly isolated cells (CLL baseline), (ii) CLL cells cultured in medium alone for 48 hours (CLL only) and (iii) CLL cells co-cultured 48h on HUVEC layer (CLL HC).
Project description:Chronic lymphocytic leukemia (CLL) is a heterogeneous malignancy, characterized by a variable clinical course. While clinical and laboratory parameters are increasingly being used to refine prognosis, they do not accurately predict response to commonly used therapy. We used gene expression profiling to generate and further refine prognostic and predictive markers. Genomic signatures that reflect progressive disease and responses to chemotherapy or chemo-immunotherapy were created using cancer cell lines and patient leukemia samples. We validated these signatures using independent clinical data from four separate cohorts representing a total of 301 CLL patients. A prognostic genomic signature created from patient leukemic cell gene expression data coupled with clinical parameters could statistically differentiate patients with stable or progressive disease in the training dataset. The progression signature was then validated in two independent datasets, demonstrating a capacity to accurately identify patients at risk for progressive disease. In addition, two distinct genomic signatures that predict response to chlorambucil or pentostatin, cyclophosphamide, and rituximab were also generated and were shown to accurately distinguish responding and non-responding CLL patients. Microarray analysis of CLL patientsâ lymphocytes can be used to refine prognosis and predict response to different therapies. These results have direct implications for standard and investigational therapeutics in CLL patients. Experiment Overall Design: For the predictive genomic signature or response to pentostatin, cyclophosphamide, and rituximab, 20 CLL leukemia samples were used in the training set, and 20 CLL leukemia samples were used in the validation set
Project description:Chronic lymphocytic leukemia (CLL) is a biologically and clinically heterogeneous disease. The somatic hypermutation status of the immunoglobulin heavy chain variable (IGHV) genes has been identified as one of the most robust prognostic markers in CLL. Patients with unmutated IGHV status (U-CLL) typically experience an inferior outcome compared to those whose clones express mutated IGHV genes (M-CLL). We conducted a genome-wide DNA methylation analysis in CD19+ B-cells from a group of 43 CLL patients using reduced representation bisulfite sequencing (RRBS). Using base-pair resolution methylation sequencing, 2323 differentially methylated regions between CLL and normal B-cells (CLL-specific DMRs) and 569 between M-CLL and U-CLL samples (IGHV-specific DMRs) were identified in the CLL genomes. The IGHV-specific DMRs are mostly unique when compared to the CLL-specific DMRs. Less than 10% of the IGHV-specific DMRs are located in promoter regions; however, more than half of these overlap with known DNase I hypersensitive sites, enhancer regions marked by histone modification (H3K4Me1 and H3K27Ac), and transcription factor binding sites in the ENCODE datasets, which indicates that these DMRs contain regulatory sequences. Distinctive DNA methylation patterns were observed in M-CLL and U-CLL samples. Overall, U-CLL was found to contain 50% more hypermethylated regions than M-CLL samples. The hypermethylated loci observed in the U-CLL samples also appear to be hypermethylated in normal naïve B-cells as compared memory B-cells, suggesting that M-CLL and U-CLL differ in differentiation status corresponding to normal B-cell differentiation stages. RNA-seq analysis performed using matched samples (n=34), in which both DNA methylation and gene expression data were available, demonstrated excellent correlation between DNA methylation and gene expression. Several genes whose expression status was previously shown to be associated with CLL prognosis such as ZAP70, CRY1, LDOC1, SEPT10, LAG3, and LPL were differentially methylated in the promoter regions between M-CLL and U-CLL samples indicating that DNA methylation plays an important role in defining the gene expression patterns of these prognostic genes. We further validated 9 genes with IGHV-specific DMRs in the promoter regions using bisulfite pyrosequencing, and the results demonstrated excellent correlation between differential methylation and IGHV mutation status. These novel differentially methylated genes could be developed into biomarkers for CLL prognosis. In addition, DNA hypomethylation was observed in a significant number of genes involved in lymphocyte activation such as PDCD1, NFAT1, and CD5. DNA hypomethylation was observed in the proximal promoter and far up-stream enhancer regions of CD5, an important cell surface marker that uniquely identifies CLL. Overall, the DNA methylation landscape in CLL patients indicates that CLL B cells possess an active B-cell phenotype; at the same time, U-CLL and M-CLL are faithfully committed to their lineage resembling either naïve or memory B-cells. In summary, this comprehensive DNA methylation analysis has identified a large number of novel epigenetic changes in CLL patients. The results from this study will further advance our understanding of the epigenetic contribution to molecular subtypes in CLL. To perform a transcriptome analysis in CLL, we generated sequencing libraries from total RNA isolated from purified B-cells of CLL patients and healthy donnors. The RNA-seq libraries were sequenced using Illumina HiSeq2000 sequencer with a read length of 100bp. 11 CLL B-cell samples, 3 normal control samples including one each of normal CD19+ B cells were studied. We generated 20-30 million Illumina sequencing reads for each sample.