Population Proteomics: Qualitative and Quantitative Analysis of Protein Markers for Obesity from Plasma Proteome

국문 초록 (Abstract)

비만은 지난 10년간 전세계적인 문제가 되었다. 비만은 그 자체로도 문제가 되지만, 다양한 질병을 유발하고 건강 상태를 악화시키기 때문에 위험도가 큰 질환이다. 전세계적 전염병이자 다양한 대사질환과 연관된 비만의 주원인으로 건강하지 못한 식습관과 유전적 요인을 꼽는다. 본 연구에서는 유전적 요인을 배제하고 비만과 비만에 의한 다양한 질병들의 위험을 나타낼 수 있는 마커 단백질을 찾아보고자 한다. 본 연구는, LC-MS/MS 분석법을 이용하여 건강한 마른 사람들과 건강한 비만인 사람들 사이의 혈장 단백질을 비교하고, 비만을 표지하는 단백질을 찾는 것이 그 목표이다. MS/MS 스펙트럼을 바탕으로, 99% 이상의 신뢰도를 보이고 2개 이상의 unique peptide를 갖는 412개의 단백질을 동정했다. 이 단백질들 가운데, 반정량분석법을 통해 발현 양의 차이를 보이는 단백질(DEPs)을 선택하였다. 각 DEPs 단백질들은 질량분석기를 기반으로 한 정량 분석, Multiple reaction monitoring 분석을 통해 확인하였다. 또한 비만에 유용한 후보 단백질을 검증하기 위해 paired t-test 통게적 분석을 수행하였다. 후보 단백질 가운데 6개 단백질은 비만 마커 단백질로의 가능성을 보였다.

다국어 초록 (Multilingual Abstract)

Obesity has in the last decade become a global problem. Obesity is a concern because of its implications for the health of an individual as it increases the risk of many diseases and heath conditions. Unhealthy diet and obesogenic lifestyle along with genetic susceptibility are the main causes of the global epidemic of obesity and related metabolic diseases. In this study, we focused on some factors that could affect to be obesity besides genetic factors and considering the risk of associated disease we need biomarkers which may represent increased risk for obesity-related diseases. This study used LC-MS/MS-based approach in obesity research to identify proteins in plasma that discriminate healthy lean from healthy overweight/obese groups and to quantify of several candidate proteins that could be biomarkers which are likely implicated in obesity. Based on MS/MS spectra of plasma proteins from lean and obesity group, we identified a total of 412 proteins with greater than 99% possibility and with at least 2 unique peptides. Among these proteins, we selected the differentially expressed proteins (DEPs), via semi-quantitative analysis of comparing the spectral counts of the identified. These DEPs were successfully verified using a MS-based quantitative assay, multiple reactions monitoring (MRM) analysis. Additionally, we performed a statistical analysis of paired t-test to validate the useful candidate proteins for obesity. Among the candidate proteins, 6 proteins were shown the possibility as marker proteins for obesity.

목차 (Table of Contents)

• 1. Introduction 1
• 2. Materials and Methods 3
• 2.1. Materials 3
• 2.1.1. Reagents 3
• 2.1.2. Instruments 4
• 2.2. Methods 5
• 2.2.1. Sample collection 5
• 2.2.2. Sample preparation and digestion 7
• 2.2.3. Analysis by Mass Spectrometry 9
• 2.2.4. Selection of the candidate proteins and MRM design 10
• 2.2.5. Quantitative analysis of selected candidate proteins by MRM 11
• 3. Result and Discussion 13
• 3.1. Protein characterization 13
• 3.2. Profiling of global proteins in plasma samples with twin participants 14
• 3.3. GO and biological process analysis of identified proteins from plasma 16
• 3.4. Verification of candidate biomarker protein associated with obesity 18
• 4. Conclusion 24
• References 25
• Abstract (in Korean) 27