ABSTRACT
Objective To investigate serum lipid profiles in newly diagnosed patients with polycystic ovary syndrome (PCOS) using lipidomics and correlate these features with hyperinsulinemia and hyperandrogenism associated with PCOS and obesity. Methods 32 newly-diagnosed PCOS women and 34 controls were enrolled and divided into obese and lean subgroups according to the body mass index (BMI). Anthropometric, biochemical, and hormonal parameters were collected. Serum lipid profiles including phospholipids, free fatty acids (FFAs), and bioactive lipids were analyzed using GC-MS and LC-MS. Results PCOS patients, in particular, the obese ones with fatty liver, have abnormal phosphatidylcholine (PC)/lysophospholipid (LPC) metabolism. PC was increased (16∶0, 18∶0, 18∶1, 18∶2, and 20∶4), while LPC was decreased (16∶0, 18∶0, and 18∶1; all P<0.05). Serum polyunsaturated fatty acids (PUFAs), were decreased significantly, and the long chain saturated fatty acid was increased. We also found that insulin stimulated the metabolism of PUFAs, but the androgen inhibits the metabolism of PUFAs by measuring their metabolites. Conclusion PCOS patients have metabolic disorders of phospholipids and PUFAs. Insulin stimulated while androgen inhibited PUFAs metabolism.
ABSTRACT
To evaluate the reagent 2-methoxy-4,5-dihydro-1H-imidazole used for isotopic labeling in quantitative proteomics, we synthesized 2-methoxy-4,5-dihydro-1H-imidazole and its tetradeuterated analog in three steps. Prior to tryptic cleavage, bovine serum albumin (BSA) was reduced and alkylated. Tryptic peptides were derivatized with an equal volume of either DO or D4 and D4-derivatized peptides were mixed with at variable ratio (from 10:1 to 1:5) prior to MS and MS/MS analysis. We used matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS) and Electro spray ionization-mass spectrometry (ESI-MS) to evaluate the quantitative capability of labeling. The specificity of the reagent is excellent: only lysine side chains were modified among tryptic peptides. MALDI and ESI ionization modes not only could achieve the quantification of differentially expressed proteins but also facilitate the de novo sequencing. This side-chain modification can be used for quantitative analysis with proteomic strategies involving liquid chromatography. Reverse phase liquid chromatography (RPLC) kept a good resolution, and the introduction of D atoms did not introduce a variation of retention time between heavy and light peptides in RPLC.
Subject(s)
Imidazoles , Chemistry , Isotope Labeling , Methods , Lysine , Chemistry , Peptides , Chemistry , Proteomics , Methods , Serum Albumin, Bovine , Chemistry , Spectrometry, Mass, Electrospray Ionization , Methods , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization , MethodsABSTRACT
Objective To screen potential serum HCC associated proteins with low molecular weight and low abundance for better understanding the pathological mechanism of HCC and discovering new biomarkers.Methods All serum samples were collected from 81 HBV-related HCC patients,43 chronic hepatitis B patients and 36 cirrhosis patients.Serum protein fingerprint profiles were first generated by selected WCX2 protein chip integrating with SELDI-TOF-MS,and then normalized and aligned by Ciphergen SELDI Software 3.1.1 with Biomarker Wizard.Comparative analysis of the intensity of corresponding protein fingerprint peaks in normalized protein spectra was performed.Some protein peaks with significant difference among HCC,cirrhosis and chronic hepatitis B groups were found.The reproducibility of the SELDI system was assessed before serum protein fingerprint profiles analysis.Results The intra-and inter-assay CV for intensity and m/z in this SELDI system were 17.46% and 0.024%,and 17.74% and 0.024% respectively.Total 128 protein fingerprint peaks between 2 000 to 30 000 Da were identified under the condition of signal to noise＞5 and minimum threshold for cluster＞20%.Eighty-seven proteins were found to significantly expressed between HCC and cirrhosis groups(P＜0.05).Of the above differential proteins,forty-five proteins had changes greater than two fold,including 15 up-regulated proteins and 30 downregulated proteins in HCC sera.Between HCC and chronic hepatitis B groups,nine of fifty-two differential proteins(P＜0.05) had intensities of more than two folds,including 2 up-regulated proteins and 7 downregulated proteins in HCC sera.Between cirrhosis and chronic hepatitis B groups,twenty-eight of seventynine significantly differential proteins(P＜0.05) changed greater than two folds in intensity,including 17 up-regulated proteins in cirrhosis seru and 11 down-regulated proteins in chronic hepatitis B sera.Analysis of above leading differential proteins among three diseases using subtraction difference mode,the 5 common down-regulated proteins 2 870,3 941,2 688,3 165 and 5 483 m/z in HCC sera and 2 common up-regulated proteins 3 588 and 2 017 m/z in cirrhosis and HCC sera were screened.But no statistic difference in the level of protein 2 017m/z was found between HCC group and normal group inour previous study.Conclusion Because the interference of unspecific proteins from hepatitis B and cirrhosis could be eliminated partly in HCC sera through subtraction difference analysis,these 6 common differential proteins (2 870,3 941,2 688,3 165,5 483,3 588 m/z)have obvious advantages of increased specificity for evaluating the pathological state of HCC and might become promising candidate biomarkers in the diagnosis of HCC.