Multiple pathways are responsible for transducing mechanical and hormonal stimuli into changes in gene expression during heart failure. In this study our goals were (i) to develop a sound statistical method to establish a comprehensive cutoff point for identification of differentially expressed genes, (ii) to identify a gene expression fingerprint for heart failure, (iii) to attempt to distinguish different etiologies of heart failure by their gene expression fingerprint, and (iv) to identify gene clusters that show coordinated up-or downregulation in human heart failure. We used oligonucleotide microarrays to profile seven nonfailing (NF) and eight failing (F) human hearts with a diagnosis of end-stage dilated cardiomyopathy. Biological and experimental variability of the hybridization data were analyzed, and then a statistical analysis procedure was developed, including Student's t test after log-transformation and Wilcoxon Mann-Whitney test. A comprehensive cutoff point composed of fold change, average difference, and absolute call was then established and validated by TaqMan PCR. Of 6,606 genes on the GeneChip, 103 genes in 10 functional groups were differentially expressed between F and NF hearts. A dendrogram identified a gene expression fingerprint of F and NF hearts and also distinguished two F hearts with distinct etiologies (familial and alcoholic cardiomyopathy, respectively) with different expression patterns. K means clustering also revealed two potentially novel pathways associated with up-regulation of atrial natriuretic factor and brain natriuretic peptide and with increased expression of extracellular matrix proteins. Gene expression fingerprints may be useful indicators of heart failure etiologies.

Genetic factors increase the risk to coronary artery disease (CAD). To date, a limited number of genes that potentially contribute to development of CAD have been identified. In this study, we have performed large-scale gene expression analysis of ∼12,000 human genes in nine severely atherosclerotic and six nonatherosclerotic human coronary arteries using oligonucleotide microarrays. Fifty-six genes showed differential expression in atherosclerotic coronary artery tissues; expression of 55 genes was increased in atherosclerotic coronary arteries, whereas only one gene, GST, encoding a reducing agent, showed downregulated expression. The expression data of selected genes were validated by quantitative RT-PCR analysis as well as immunostaining. The associations of 49 genes with CAD appear to be novel, and they include genes encoding ICAM-2, PIM-2, ECGF1, fusin, B cell activator ( BL34, GOS8), Rho GTPase activating protein-4, retinoic acid receptor responder, β2-arrestin, membrane aminopeptidase, cathepsins K and H, MIR-7, TNF-α-induced protein 2 (B94), and flavocytochrome 558. In conclusion, we have identified 56 genes whose expression is associated with CAD, and 49 of them may represent new genes linked to CAD.

In chickens, oviposition is correlated with increased plasma levels of the neurohypophysial hormone vasotocin, and vasotocin stimulates contraction of uterine strips in vitro. A gene encoding a vasotocin receptor subtype that we have designated the VT1 receptor was cloned from the domestic chicken. The open reading frame encodes a 370-amino acid polypeptide that displays seven segments of hydrophobic amino acids, typical of guanine nucleotide-protein-coupled receptors. Other structural features of the VT1 receptor include two potential N-linked glycosylation sites in the extracellular N-terminal region, a conserved aspartic acid in transmembrane domain 2 that is found in nearly all guanine nucleotide-protein-coupled receptors, and two potential protein kinase C phosphorylation sites in the third intracellular loop and C-terminal tail. Expressed VT1 receptors in COS7 cells bind neurohypophysial hormones with the following rank order of potency: vasotocin congruent with vasopressin > oxytocin congruent with mesotocin > isotocin. In addition, the expressed VT1 receptor mediates vasotocin-induced phosphatidylinositol turnover and Ca(2+) mobilization. In the chicken, expression of VT1 receptor gene transcripts is limited to the shell gland (uterus) and the brain. Thus, the VT1 receptor that we have cloned may mediate contractions of the shell gland during oviposition and activate reproductive behaviors known to be stimulated by vasotocin in lower vertebrates.

Taken together with previous monoclonal antibody epitope mapping studies, our results suggest that a limited number of exposed domains on the surface of the human VWF protein may be the primary determinants of immunogenicity.