PHB1 and PHB2 are physically interactive and functionally interdependent in various organisms

the United States. In contrast, in developing countries VHD is still mainly caused by rheumatic heart disease, although the percentage 1973737 of heart valve surgery for DVD in these countries is also increasing. In fact, in China, the incidence of rheumatic heart disease is reported to be as high as 0.2% of the adult population, 10 times higher than that in developed countries, and China is estimated to have about 2 million adult rheumatic heart disease patients. The genetic basis and proteomics of common VHD are important to provide information for diagnosis and treatment of these diseases. Proteomics is a powerful tool to describe changes in protein expression developing a map of proteins, and more importantly, proteomics allows us to identify protein isoforms in plasma. In fact, plasma is the ideal source for proteome analysis as it is easily sampled from patients and reflects processes in anatomical compartments. As a complex body fluid, more than 10,000 different proteins are present in human plasma and many Proteomics in Valvular Heart Disease of them are ATL-962 secreted or shed by cells during different physiological or pathological processes. Plasma is expected to be an excellent source of protein biomarkers because it circulates through, or comes in contact with all tissues. During this contact it is likely to pick up proteins secreted or shed by tissues. The proteome reflects all proteins and peptides that may be related to certain genes and allows a more detailed evaluation of disease status. The fundamental problem in proteomics is the individuality of different proteins. Separation 21346199 of large numbers of proteins is normally done by two-dimensional electrophoresis. The resulting proteins which are separated with 2-DE are normally identified by mass spectrometry, especially the matrixassisted laser desorption-ionization time-of-flight mass spectrometry , as we recently reported in our work on congenital heart diseases. However, although there were few proteomic studies on VHD, most of them studied tissues and there were only handful studies on RVD. Further, there were no reports on the proteomic study on the comparison between DVD and RVD. Proteomics in Valvular Heart Disease RVD n MVR AVR MVR+AVR 22 0 18 % 55 0 45 DVD n 20 16 4 % 50 40 10 normalization of the image by taking the ratio of intensity of one spot to the total spots, and expressed as a fractional intensity. Only those spots with significant change in expression intensity were selected for mass spectrometry analysis. Tryptic Digestion Protein spots were excised from the gel with the Ettan Spot Picker and destained with 25 mM ammonium bicarbonate, 50% acetonitrile. Gels were then dried completely by centrifugal lyophilization. Each spot was digested overnight in 8 m 10.1 mg/ ml trypsin for 16 h at 37uC. The peptides were extracted three times with 50% acetonitrile, 0.1% trifluoroacetic acid, and dried completely by centrifugal lyophilization. RVD = rheumatic valvular disease; DVD = degenerative valvular disease; MVR: mitral valve replacement; TVR: with or without concomitant tricuspid valve repair; AVR: aortic valve replacement. doi:10.1371/journal.pone.0072111.t003 MALDI/TOF MS Before the analysis, external calibration with angiotensin II and ACTH 1839 was employed. This procedure typically results in mass accuracies of 100 ppm or better. Then, the peptide mixture was mixed with a-cyano-4-hydroxycinnamic acid matrix and analyzed on a MALDI/TOF MS, operated in the delayed extra