Lyang-Ja Lee

Quantitative peptidomic analysis by a newly developed one‐step direct transfer technology without depletion of major blood proteins: Its potential utility for monitoring of pathophysiological status in pregnancy‐induced hypertension

We have recently developed a new target plate (BLOTCHIP®) for MALDI‐MS. An advantage of this procedure is that it does not require the lowering of protein concentrations in test samples prior to analysis. Accordingly, this new technology enables the detection of peptides present in blood samples, including those that would otherwise be adsorbed to abundant blood proteins and would thus escape detection. Using this technology, we analyzed the peripheral blood of patients with pregnancy‐induced hypertension (PIH; the most common serious complication of pregnancy) to test a potential utility of the technology for monitoring of the pathophysiological status. In the present study, we found 23 characteristic peptides for PIH in the blood serum of pregnant women. Offline LC‐MALDI MS/MS identified 7 of the 23 peptides as fragments derived from kininogen‐1 (three peptides), fibrinogen‐α, complement component C4‐A/B, α‐2‐HS‐glycoprotein and inter‐α‐trypsin inhibitor heavy chain H4. 2‐D scatter plots with combinations of the peptides found in the present study can be grouped for pregnant women with/without PIH, which would be satisfactory reflected for their status. Additionally, the levels of most of these peptides found were significantly decreased by albumin/IgG depletion prior to BLOTCHIP® analysis in accordance with conventional proteomics procedures. These results indicated that BLOTCHIP® analysis can be applied for discovery study of PIH biomarker candidates.

A new rapid and comprehensive peptidome analysis by one-step direct transfer technology for 1-D electrophoresis/MALDI mass spectrometry.

We have developed a new target plate for matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS). This target plate enables direct electric transfer of analytes from the 1-dimensional gel electrophoresis (1-DE) gel to the target plate in one step. Incorporated with a one-step direct transfer technique, this novel 1-DE/MALDI-MS (1-DE/MS) system eliminates staining, extracting, loading, and many other time-consuming intermediate processes, thereby greatly reducing analysis time while providing high throughput proteome analysis. Furthermore, in peptidome analysis, during the 1-DE step this system separates or removes the high molecular weight plasma proteins in blood and the various low molecular weight substances in tissue extracts, which interfere with mass spectrometry. This system can therefore be used for peptide profiling of any biological sample without special pretreatment. In view of these advantages, the 1-DE/MS system will greatly improve the usefulness of current peptidomic modalities in the discovery and validation of biomarker molecules in various body fluids and tissue extracts, permitting early detection, diagnosis, and treatment of diseases.

Diagnostic value of serum peptidome analyses for protease activated pathological conditions beyond cancer diagnosis.

Human serum contains thousands of proteolytically derived low-molecular-weight peptide fragments (serum peptidome). The concept of utilizing the serum peptidome for cancer diagnosis has been developed. A pathological serum peptidome appears when the homeostatic balance between proteases and protease inhibitors is disrupted. We hypothesize if analyses of the serum peptidome are of diagnostic value as information on which molecules are disrupted, and the pathological course it will take in unknown pathological conditions and disseminated intravascular coagulation (DIC). We analyzed the serum peptidome in 3 stages (early stage, pre-DIC and DIC stages) in one patient with POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein and skin changes) syndrome, an intractable disease with unknown pathology, using a 1-dimensional gel electrophoresis/matrix-assisted laser desorption/ionization-mass spectrometry (1-DE/MS)-based rapid quantitative approach. A very large number of peptide fragments appeared in the DIC stage, compared to pre-DIC. In addition, we identified fragments of transthyretin (ALGISPFHEHAEVVFTANDSGPR, m/z 2451.18) and alpha1-antitrypsin (EDPQGDAAQKTDTSHHDQDHPTFN, m/z 2691.02) that significantly increased in the DIC stage, compared to those in the pre-DIC stage. Rapid analyses of the serum peptidome may lead to a diagnostic method that can predict on-going protease activated pathological conditions and help to decide on multilateral strategies including nutritional support and drug therapy.

Clinical peptidomic analysis by a one‐step direct transfer technology: Its potential utility for monitoring of pathophysiological status in female reproductive system disorders

To date, numerous studies have searched for candidate molecules or clinical examination methods as potential biomarkers for monitoring intractable diseases, such as carcinomas. Evidence accumulated over the past decade shows that many proteolytic peptides appear in human humoral fluids, including peripheral blood, in association with an individuals health condition. Although an analysis of the whole peptide (the ‘peptidome’) using mass spectrometry is thought to be one of the most powerful and promising experimental approaches, it has failed to identify biomarkers in the clinical blood samples, presumably due to the methodological limitations. In general, commonly used techniques for proteomic analysis of blood require the removal of large amounts of serum/plasma proteins prior to mass spectrometry analysis, and this step seems to have resulted in the overlooking of important biomarkers during the analytical process. Here, we provide a brief overview of a new quantitative peptidomic analysis by a one‐step direct transfer technology without depletion of major blood proteins. Using this technology, we herein report experimental data on serum peptidomic analysis for patients with pregnancy‐induced hypertension as a clinical model. In addition, we refer to the potential utility of this approach for the monitoring of pathophysiological status in female reproductive system disorders in general.

Simple quantitation for potential serum disease biomarker peptides, primarily identified by a peptidomics approach in the serum with hypertensive disorders of pregnancy:

Background We previously reported peptide candidates of disease biomarkers for pregnancy-induced hypertension syndrome using a novel peptidomic analytical method, BLOTCHIP®-MS. The aim of this study was to establish a sandwich enzyme-linked immunosorbent assay system for quantitation of such peptides and to validate their usefulness as disease biomarkers of pregnancy-induced hypertension syndrome including gestational hypertension/pre-eclampsia. Methods We focused on three peptide fragments, kininogen-1439–456 (PDA039), kininogen-1438–456 (PDA044) and cysteinyl α2-HS-glycoprotein341–367 (PDA071). Using polyclonal antibodies specific for each peptide, suitable conditions for the sandwich enzyme-linked immunosorbent assay system were investigated. The quantitative enzyme-linked immunosorbent assay values were confirmed by quantitative matrix assisted laser desorption/ionization time-of-flight MS analyses. Using the established enzyme-linked immunosorbent assay systems, serum samples from gestational hypertension/pre-eclampsia patients and paired serum samples from healthy pregnant females were analysed. Results The optimum sandwich enzyme-linked immunosorbent assay conditions for PDA039/044 quantitation were developed. Quantitation of PDA071 by enzyme-linked immunosorbent assay failed, presumably due to issues with polyclonal antibody specificity for the native peptide. Bland–Altman plots showed a satisfactory correlation between the serum PDA039/044 concentration by enzyme-linked immunosorbent assay and that by quantitative MS analysis. Although the PDA044 concentration showed no significant change during pregnancy, including gestational hypertension/pre-eclampsia patients, the serum PDA039 concentration was significantly increased (P < 0.0001) in the patients. Conclusions The simple quantitation technology for PDA039 by enzyme-linked immunosorbent assay was established for the first time. PDA039 confirmed its clinical utility as a disease biomarker for gestational hypertension/pre-eclampsia by the enzyme-linked immunosorbent assay system using clinical samples. The information provided from the present study would be a new valuable addition in the field of gestational hypertension/pre-eclampsia research.

Selected reaction monitoring for colorectal cancer diagnosis using a set of five serum peptides identified by BLOTCHIP®-MS analysis

BackgroundColorectal cancer (CRC) is one of the most predominant types of cancer, and it is the fourth most common cause of cancer-related death and it is important to diagnose CRC in early stage to decrease the mortality by CRC. In our previous study, we identified a combination of five peptides as a biomarker candidate to diagnose CRC by BLOTCHIP®-MS analysis using a set of healthy control subjects and CRC patients (stage II–IV). The aim of the present study was to validate the serum biomarker peptides reported in our previous study using a second cohort and to establish their potential usefulness in CRC diagnosis.MethodsA total of 56 patients with CRC (n = 14 each of stages I–IV), 60 healthy controls, and 60 patients with colonic adenoma were included in this study. The five peptides were extracted and analyzed by selected reaction monitoring using ProtoKey® Colorectal Cancer Risk Test Kit (Protosera, Inc., Amagasaki, Japan).ResultsThe results clearly showed that the four CRC groups, stages I–IV, could be sufficiently discriminated from the control group and colonic polyp group. This five-peptide set could identify CRC at each stage compared to the control population in this validation cohort, including those with early-stage disease. The AUC values for each stage of CRC compared to the control population were 0.779, 0.946, 0.852, and 0.973 for stages I, II, III, and IV, respectively.ConclusionsIn this case–control validation study, we confirmed high diagnostic performance for CRC using five peptides that were identified in our previous study as serum biomarker candidates for the detection of CRC.

New Biomarkers for Prediction of Disseminated Intravascular Coagulation in Patients With Sepsis

Complication of disseminated intravascular coagulation (DIC) is a determinant of the prognosis for patients with sepsis. The purpose of this study was to find DIC-related peptides in blood for prediction and early diagnosis of DIC in patients with sepsis. The participants were 20 patients with sepsis (age: 68.9 ± 11.4 years) and they were divided into 2 groups with (n = 8) and without (n = 12) a complication of DIC. Peptides in the serum of the patients were inclusively analyzed by a new method for peptidome analysis using a target plate, BLOTCHIP. By differential analysis of peptides in the blood from patients in the groups with and without DIC, we selected 13 mass spectrometry (MS) peaks as candidate marker peptides for prediction of DIC. By subsequent MS/MS structural analysis, 8 peptides were successfully identified as marker peptides for DIC in patients with sepsis. The peptides were fragments of serum amyloid A-2 protein, α2-HS-glycoprotein, fibrinogen α chain, fibrinogen β chain, serum albumin, collagen α1 (I) chain, collagen α1 (III) chain, and coagulation factor XIII A chain. In receiver–operating characteristic analysis for the relationships between the marker peptides and DIC, the area under the curve for each of these peptides was 0.594 to 0.760. We identified 8 blood marker peptides for prediction of DIC complication in patients with sepsis. Further studies by direct measurements of the serum peptide levels in larger numbers of patients with sepsis-induced DIC are needed to confirm the findings of this study.

Cysteinylated transthyretin as a discriminator of cardiovascular risk in patients with diabetes mellitus

BACKGROUND The cysteine residue on transthyretin (TTR) is susceptible to be oxidized, and serum cysteinylated TTR (Cys-TTR) level is thought to reflect oxidative stress. The purpose of this study was to elucidate the relationship between Cys-TTR and arterial stiffness, a known predictor of cardiovascular disease, in patients with type 2 diabetes. METHODS The subjects were 105 male outpatients with type 2 diabetes. Arterial stiffness was evaluated by measuring cardio-ankle vascular index (CAVI). The relationship between CAVI and ratio of Cys-TTR to total TTR (Cys-TTR ratio) was analyzed. RESULTS Cys-TTR ratio was significantly correlated with CAVI (Pearsons correlation coefficient: 0.316, p<0.01), and CAVI was significantly higher in the 3rd tertile group for Cys-TTR ratio than in its 1st tertile group. These relationships were also significant after adjusting for age, smoking, alcohol drinking, body mass index, mean arterial pressure, hemoglobin A1c, LDL cholesterol-to-HDL cholesterol ratio and eGFR. Prevalence of high CAVI (≥10.0) was significantly higher in the 3rd tertile for Cys-TTR ratio than in its 1st tertile and tended to be higher with an increase in tertile (28.6% in the 1st tertile, 42.9% in the 2nd tertile and 60.0% in the 3rd tertile). Odds ratio (OR) for high CAVI of the 3rd vs. 1st tertile groups for Cys-TTR ratio was significantly higher than the reference level of 1.00 both before and after adjustment for the above cardiovascular risk factors (crude OR, 3.75 [1.38-10.17]; adjusted OR, 5.09 [1.39-18.64]). CONCLUSIONS Cys-TTR ratio is associated with arterial stiffness in patients with diabetes and is proposed as a new discriminator of cardiovascular risk.

Potential Biomarker Peptides Associated with Acute Alcohol-Induced Reduction of Blood Pressure.

The purpose of this study was to explore the peptides that are related to acute reduction of blood pressure after alcohol drinking. Venous blood was collected from male healthy volunteers before and after drinking white wine (3 ml/kg weight) containing 13% of ethanol. Peptidome analysis for serum samples was performed using a new target plate, BLOTCHIP®. Alcohol caused significant decreases in systolic and diastolic blood pressure levels at 45 min. The peptidome analysis showed that the levels of three peptides of m/z 1467, 2380 and 2662 changed significantly after drinking. The m/z 1467 and 2662 peptides were identified to be fragments of fibrinogen alpha chain, and the m/z 2380 peptide was identified to be a fragment of complement C4. The intensities of the m/z 2380 and m/z 1467 peptides before drinking were associated with % decreases in systolic and diastolic blood pressure levels at 45 min after drinking compared with the levels before drinking, while there were no significant correlations between the intensity of the m/z 2662 peptide and % decreases in systolic and diastolic blood pressure levels after drinking. The m/z 1467 and 2380 peptides are suggested to be markers for acute reduction of blood pressure after drinking alcohol.