Gene expression of C-type natriuretic peptide and of its specific receptor NPR-B in human leukocytes of healthy and heart failure subjects

C-type natriuretic peptide (CNP), a member of the family of natriuretic peptides, is synthesized and secreted from monocytes and macrophages that resulted to be a source of CNP at inflammatory sites. This suggests that special attention should be focused on the possible role of CNP in the immune system, in addition to its effects on the cardiovascular system. The aim of this study was to evaluate the possibility of measuring the mRNA expression of CNP and NPR-B, its specific receptor, in human whole blood samples of healthy (N; n=7) and heart failure (HF; n=7) subjects by Real-Time PCR (RT-PCR). Total RNA was extracted from leukocytes with QIAamp RNA Blood Kit and/or with PAXgene Blood RNA Kit. RT-PCR was performed and optimized for each primer. The experimental results were normalized with the three most stably expressed genes. CNP and NPR-B expression trend was similar in both fresh and frozen human whole blood. Significant higher levels of CNP and NPR-B mRNA expression were found in HF patients with respect to controls (CNP: N=1.23±0.33 vs. HF=6.54±2.09 p=0.027; NPR-B: N=0.85±0.23 vs. HF=5.31±1.98 p=0.04). A significant correlation between CNP and NPR-B (r=0.86, p<0.0001) was observed. Further studies are needed to clarify the pathophysiological properties of this peptide but the possibility to measure CNP and NPR-B mRNA expression in human leukocytes with a fast and easy procedure is a useful starting point for future investigation devoted to better understand the biomolecular processes associated to different diseases.