Project description:Objectives: To test whether (1) electromechanical dyssynchrony induces region-specific alterations in the myocardial transcriptome and (2) dyssynchrony-induced gene expression changes can be corrected by cardiac resynchronization (CRT). Background: To date, CRT is the only heart failure treatment that can both acutely and chronically increase systolic function and prolong survival, something not yet achieved by a drug therapy. However, the mechanisms underlying the benefits of CRT remain elusive. Methods: Adult dogs underwent left bundle branch ablation (LBBB) and right atrial pacing at 200 bpm for either 6 weeks (dyssynchronous heart failure, DHF, n=12) or 3 weeks followed by 3 weeks of resynchronization by bi-ventricular pacing at the same pacing rate (CRT, n=10). Control animals without LBBB were not paced (NF, n=14). Echocardiography and invasive hemodynamic measurements were performed at 3 and 6 weeks. At 6 weeks, RNA was isolated from the anterior and lateral LV walls and hybridized onto canine-specific 44K microarrays. Results: In DHF, transcriptional changes consistent with re-expression of a fetal gene program were primarily observed in the anterior LV, resulting in increased regional heterogeneity of gene expression within the left ventricle. Dyssynchrony-induced region-specific expression changes in 1050 transcripts were reversed by CRT to levels of NF hearts (false discovery rate <5%). CRT remodeled transcripts with metabolic and cell signaling function and greatly reduced regional heterogeneity of gene expression compared with DHF. Conclusions: Our results demonstrate a profound effect of electromechanical dyssynchrony on the regional cardiac transcriptome, causing gene expression changes primarily in the anterior LV wall. CRT corrected the alterations in gene expression in the anterior wall by reversing the fetal gene expression pattern, supporting a global effect of biventricular pacing on the ventricular transcriptome that extends beyond the pacing site in the lateral wall. Designed as a 1-color experiments, samples from anterior and lateral left ventricular myocardium from non-failing, DHF and CRT animals were labeled with Cy3 and hybridized onto Agilent 44K long oligonucleotide arrays.

Project description:Objectives: To test whether (1) electromechanical dyssynchrony induces region-specific alterations in the myocardial transcriptome and (2) dyssynchrony-induced gene expression changes can be corrected by cardiac resynchronization (CRT). Background: To date, CRT is the only heart failure treatment that can both acutely and chronically increase systolic function and prolong survival, something not yet achieved by a drug therapy. However, the mechanisms underlying the benefits of CRT remain elusive. Methods: Adult dogs underwent left bundle branch ablation (LBBB) and right atrial pacing at 200 bpm for either 6 weeks (dyssynchronous heart failure, DHF, n=12) or 3 weeks followed by 3 weeks of resynchronization by bi-ventricular pacing at the same pacing rate (CRT, n=10). Control animals without LBBB were not paced (NF, n=14). Echocardiography and invasive hemodynamic measurements were performed at 3 and 6 weeks. At 6 weeks, RNA was isolated from the anterior and lateral LV walls and hybridized onto canine-specific 44K microarrays. Results: In DHF, transcriptional changes consistent with re-expression of a fetal gene program were primarily observed in the anterior LV, resulting in increased regional heterogeneity of gene expression within the left ventricle. Dyssynchrony-induced region-specific expression changes in 1050 transcripts were reversed by CRT to levels of NF hearts (false discovery rate <5%). CRT remodeled transcripts with metabolic and cell signaling function and greatly reduced regional heterogeneity of gene expression compared with DHF. Conclusions: Our results demonstrate a profound effect of electromechanical dyssynchrony on the regional cardiac transcriptome, causing gene expression changes primarily in the anterior LV wall. CRT corrected the alterations in gene expression in the anterior wall by reversing the fetal gene expression pattern, supporting a global effect of biventricular pacing on the ventricular transcriptome that extends beyond the pacing site in the lateral wall.

Project description:T cells contribute to host-tumor interactions in patients with monoclonal gammopathies. Expansions of CD8+CD57+TCRVÎ²+ restricted cytotoxic T cell (CTL) clones are found in 48% of patients with multiple myeloma and confer a favorable prognosis. We now report the presence of CTL clones with varying TCRVÎ² repertoire in 70% of patients with Waldenstromâs Macroglobulinaemia (WM) (n=20). Previous nucleoside analogue (NA) therapy, associated with an increased incidence of transformation to aggressive lymphoma, significantly influenced the presence of TCRVÎ² expansions (X2=11.6; P<0.001) as 83% of patients without (n=6) and only 7% with TCRVÎ² expansions (n=14) had received NA. Clonality of CD3+CD8+CD57+TCRVÎ²+ restricted CTLs were confirmed by TCRVÎ² CDR3 size analysis and direct sequencing. To characterize CTL clones, samples of CD3+CD8+CD57+TCRVÎ²+ cells were profiled using DNA microarrays and the results were validated on both gene and protein level. By gene set enrichment analysis, CTL clones not only expressed genes (GZMB, PRF1, FGFBP2) from cytotoxic pathways but also genes which suppress apoptosis, inhibit proliferation, arrest cell cycle G1/S transition and activate T cells (RAS, CSK and TOB pathways). Proliferation tracking confirmed their anergic state. Our studies demonstrate the incidence, NA sensitivity and anergic nature of clonal T cells in a B cell tumor. We used microarrays to detail the global programme of gene expression underlying T cell clonal expansion and identified distinct classes of up-regulated genes during this process. Experiment Overall Design: In this study we have sought T cell clones in the blood of patients with WM and related their presence with nucleoside analog therapy and transformation. We have also sorted CD3+CD4-TCRVÎ²+CD57+ from CD3+CD4-TCRVÎ²+CD57- cells and confirmed clonality by TCRVÎ² CDR3 size determination and sequencing and used carboxy-fluorescein diacetate succinmidyl ester (CFSE) tracking to monitor proliferation of CD3+CD4-TCRVÎ²+CD57+ clones. Finally we have performed microarray analysis to search for significant differentially expressed genes and pathways in the clonally expanded CD3+CD8+TCRVÎ²+CD57+ cells, focusing on cytotoxic pathways but also identifying other dysfunctional changes in these cells. Expression of a selection of the most differentially expressed genes detected by microarray was validated at both gene (qPCR) and protein level.

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Cardiac Resynchronization Therapy (2-color design)

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