Real-time RT-PCR for gene expression profiling in blood of heart failure patients-a pilot study: gene expression in blood of heart failure patients.

Cardiovascular diseases are associated with multiple changes in gene expression. In general, cardiac tissue is not accessible to expression analysis. This study was designed to investigate expression of cardiac significant genes in white blood cells of heart failure patients and to identify differentially expressed genes. The quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) method was used for quantification of messenger RNA (mRNA) transcripts in blood samples of 20 patients (NYHA III-IV) with severe heart failure and of 20 healthy controls (NYHA I). Total RNA was extracted from leukocytes, reverse transcribed into cDNA, amplified and quantitated by SYBR Green detection. Relative mRNA expression was calculated using phosphoglycerate kinase-1 ( PGK-1) gene expression as an endogenous reference. Identified were 14 genes relevant to cardiomyocyte excitability or contractility. Most of them had not been previously reported to be expressed in blood cells. Data was based on 0.5 micro g total RNA applied to RT-PCR and on leukocyte number. In both, an increased transcription level of the Na/Ca exchanger ( NCX) was found in blood of heart failure patients as compared to controls (p < 0.02), in line with an upregulated NCX expression known from myocardial tissue of heart failure patients. This pilot study demonstrates that NCX transcription increased in potential relation to heart failure disease.

Exogenous nitric oxide causes overexpression of TGF-beta1 and overproduction of extracellular matrix in human coronary smooth muscle cells.

OBJECTIVE: Nitric oxide (NO) is a major signalling molecule in the vascular system enhancing vascular smooth muscle cell relaxation and vasodilation. NO donors are the most frequently and repeatedly used drugs for relief from angina pectoris. METHODS: We investigated the effects of the synthetic NO donor DETA/NO on cultured human coronary smooth muscle cells. RESULTS: Cells exposed to 100 microM DETA/NO for 48-72 h were channeled into a cell cycle-arrested hypertrophic growth status associated with overexpression of TGF-beta(1) on both the protein and mRNA levels. Increased TGF-beta(1) transcription and translation were associated with enhanced synthesis of extracellular matrix components including the collagen types I and III as shown by immunocytochemistry and enhanced incorporation of [3H]proline. Higher incorporation of [35S]sulfate into chondroitin/dermatan sulfate and heparan sulfate containing proteoglycans was observed in DETA/NO treated cells than in controls. The ratio of chondroitin/dermatan sulfate to heparan sulfate did not change significantly. CONCLUSIONS: Our results suggest a dual function of the overexpressed TGF-beta(1). Overexpressed TGF-beta(1) could stabilize the fibrous cap overlaying atherosclerotic plaques due to the accumulation of extracellular matrix components. However, the findings could also support a proatherogenic role of TGF-beta(1) resulting from the overexpression of LDL-binding proteoglycans.

Identification and functional characterization of hemorphins VV-H-7 and LVV-H-7 as low-affinity agonists for the orphan bombesin receptor subtype 3.

1. The human orphan G-protein coupled receptor bombesin receptor subtype 3 (hBRS-3) was screened for peptide ligands by a Ca(2+)mobilization assay resulting in the purification and identification of two specific ligands, the naturally occurring VV-hemorphin-7 (VV-H-7) and LVV-hemorphin-7 (LVV-H-7), from human placental tissue. These peptides were functionally characterized as full agonists with unique specificity albeit low affinity for hBRS-3 compared to other bombesin receptors. 2. VV-H-7 and LVV-H-7 induced a dose-dependent response in hBRS-3 overexpressing CHO cells, as well as in NCI-N417 cells expressing the hBRS-3 endogenously. The affinity of VV-H-7 was higher in NCI-N417 cells compared to overexpressing CHO cells. In detail, the EC(50) values were 45+/-15 microM for VV-H-7 and 183+/-60 microM for LVV-H-7 in CHO cells, and 19+/-6 microM for VV-H-7 and 38+/-18 microM for LVV-H-7 in NCI-N417 cells. Other hemorphins had no effect. Gastrin-releasing peptide (GRP) and neuromedin B (NMB) showed similar EC(50) values of 13-20 microM (GRP) and of 1-2 microM (NMB) on both cell lines. 3. Structure-function analysis revealed that both the N-terminal valine and the C-terminal phenylalanine residues of VV-H-7 are critical for the ligand-receptor interaction. 4. Endogenous hBRS-3 in NCI-N417 activated by VV-H-7 couples to phospholipase C resulting in changes of intracellular calcium, which is initially released from an inositol trisphosphate (IP(3))-sensitive store followed by a capacitive calcium entry from extracellular space. 5. VV-H-7-induced hBRS-3 activation led to phosphorylation of p42/p44-MAP kinase in NCI-N417 cells, but did not stimulate cell proliferation. In contrast, phosphorylation of focal adhesion kinase (p125(FAK)) was not observed.

[Long QT-syndromes: diagnosis and genetics]. / Angeborene QT-Syndrome : Diagnostik und Genetik.

The long-QT syndrome (LQTS) is a familiar disease characterized by abnormal myocardial repolarization and a high risk of sudden cardiac death. As a hallmark of the disease, the heart-rate corrected QT interval is intrinsically prolonged. Recent advances in molecular genetics have elicited that various inborn defects in cardiac ion channel genes regulating cardiac ion currents underlie this propensity to develop malignant ventricular arrhythmias. Meanwhile, a widespread locus and allelic genetic heterogeneity in LQTS is evident, thus, complicating the power of DNA diagnostic tools. The following review will briefly summarize clinical and genetic aspects of LQTS.