Plasma Proteomic Analysis Of Type 2 Diabetes Mellitus And Hepatocellular Carcinoma Based On Label-free Quantitative Technology

In recent years,with the rapid development of mass spectrometry instruments,MS-based proteomics technology has been able to conduct in-depth and comprehensive research on complex biological specimens,and has become a powerful analysis platform for clinical disease biomarker discovery.Blood is the most important biological specimen in the diagnosis of clinical diseases.There are many kinds of proteins in blood,and many of them have been identified as biomarkers or target proteins,which has great application significance for clinical disease diagnosis,treatment and prognosis.Herein,based on label-free quantitative technology,we carried out the plasma proteomics research of major diseases,including type 2 diabetes(T2D)and hepatocellular carcinoma(HCC),in order to discovery the candidate plasma biomarkers for early diagnosis of diseases and provide theoretical basis for revealing the molecular pathological mechanism of diseases.This thesis consists of two parts.Chapter one: Diabetes mellitus,as a group of chronic metabolic diseases with long duration,the incidence and mortality rate increase year by year,which makes people suffer from the devastating physical and mental pain and financial burden.At present,it has become a global public health issue.The number of diabetes patients in China ranks first in the world,and more than 90% of them are T2 D.The key to control T2 D is to delay the progression and deterioration of T2 D by early prevention and diagnosis.It is of great significance to discover candidate plasma protein markers of T2 D by plasma proteomics technology for early prevention and diagnosis of disease.Therefore,based on the label-free quantitative technology,we carried out the integrated analysis of proteomics and glycoproteomics of plasma samples from 8 patients with T2 D,8 subjects with prediabetes(PDB)and8 healthy controls(HC).The results of proteomics research identified 19 differentially expressed plasma proteins between T2 D and HC groups,of which 3 were up-regulated in T2 D patients and 16 were down-regulated in T2 D patients.Global plasma proteomic analysis also revealed that the dysfunction of the immune response might be a novel characteristic of T2 D patients,as many immunoglobulins were lost in T2 D,such as IGHM,IGKC,IGLC3 and IGKV3D-30 proteins.The results of glycoproteomics analysis identified 83 differentially expressed N-glycopeptides among HC,PDB and T2 D groups.The integrated analysis of proteomics and glycoproteomics identified several N-glycosylation dysregulated pathways dominant in the plasma of T2 D,including platelet degranulation,fibrin blot formation,IGF regulation and complement cascade pathways.We also particularly identified systemic site-specific N-glycosylation alterations in complement activation pathways of T2 D patients,and suggested new opportunities for diagnosis and treatment of diabetes disease.Chapter two: Liver cancer is a kind of malignant tumor with high incidence and poor prognosis,and it is also the fourth common cause of cancer-related death.Its high incidence and mortality rate are facing severe challenges and threats to human life quality and life and health.China is a large country of liver cancer,90% of primary liver cancer patients are hepatocellular carcinoma.However,the current clinical diagnosis of HCC is not optimistic,and there is still a lack of satisfactory biomarkers.It is urgent to find novel diagnostic markers with high sensitivity and specificity in order to improve the diagnostic accuracy and detection rate.Therefore,based on the label-free quantitative technology,we conducted a plasma proteomic study of 10 patients with HCC and 10 subjects with HC,and identified a group of potential biomarkers for the diagnosis of HCC,including 16 upregulated proteins and 15 down-regulated proteins.Enrichment analysis of cell biological process showed that up-regulated proteins were mainly involved in the process of platelet degranulation,platelet activation,acute phase reaction and other biological processes,while down-regulated proteins were mainly concentrated in a series of metabolic processes such as retinol metabolic process and retinoid metabolic process.Among them,VWF,LGALS3 BP,FGG,FGB,FGG,PIGR,IGFALS and APOF have been reported to be associated with HCC.Moreover,a series of novel biomarkers were found,such as EFEMP1,ITH3,CRP,SAA1,LBP and MBL2.The relationship and mechanism between them and the occurrence and development of HCC are worthy of further exploration.In conclusion,in view of the limitations of current diagnostic methods for T2 D and HCC,and the demand for effective blood biomarkers,this project is based on then label-free quantitative technology of proteomics and comprehensive data analysis.On the one hand,we conducted the comprehensive analysis of plasma proteomics and glycoproteomics for T2 D,on the other hand,we carried out a study of the plasma proteomics of HCC.Our study found a series of plasma candidate biomarkers for the diagnosis of type 2 diabetes and hepatocellular carcinoma,which provided theoretical basis for revealing the molecular pathological mechanism of the disease.The analysis of glycoproteomics provided a new direction for revealing the molecular pathological mechanism of type 2 diabetes,and provided a new possibility for the diagnosis and treatment of the disease.