149 IDENTIFICATION OF DIFFERENTIALLY EXPRESSED PROTEINS IN THE UMBILICAL CORDS OF TERM AND PRE-TERM (35–36 WEEKS) INFANTS USING PROTEOMICS

Abstract

Pre-term infants born before the end of the 37th week of pregnancy have not been exposed to their mother's womb full-term. Because they are born too soon, many of their biological systems, such as those involving the lungs and liver, are not developed enough to work property on their own. The lungs are not functional in the fetus, and the blood passes directly from the right atrium to the left atrium or from the right ventricle to the aorta. In this study, we analyzed protein profiles in the umbilical cord of term and pre-term infants by 2DE and MALDI-TOF analysis. Protein patterns of the umbilical cord were established using the pH range 4–7, isoelectric focusing (IEF) cell system, and 7.5–17.5% gradient 2-dimensional polyacrylamide gel electrophoresis (2DE). Image analysis was performed following Coomassie brilliant blue G staining to reveal spots, and spot intensities were compared using a PDQuest analysis system. Peptide mass fingerprinting with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and a SWISS-PROT database search were utilized to identify proteins. Around 1000 protein spots were recognized by image analysis for umbilical cords from each treatment. Analysis of umbilical cords from pre-term infants revealed 35 different spots compared with those from full-term infants. Levels of 12 proteins increased, such as serum albumin precursor and tropomyosin, whereas levels of 11 proteins decreased, including 78 kDa glucose-regulated protein and protein disulfide isomerase A3. Another 12 proteins had levels that were different between 35 and 36 weeks of pregnancy. In general, proteins that increased represented precursor and cell mobility or structure-related proteins, whereas proteins that decreased included chaperon-related proteins. Expression levels of this protein were confirmed by Western blot analysis and real-time PCR. The results of this experiment suggest differential protein profiles between umbilical cords of pre-term and full-term infants that may be related to fetal circulation and early birth of infant.