Abstract
PROJECT I Effect of High Glucose on Expression Proteome, Redox-Proteome and Secreted-Proteome in Cultured Retinal Pigmented Epithelium Cells Its Possible Relevance to Diabetic Retinopathy Retinopathy has been observed in around 25% of diabetic patients. Previous research has suggested that diabetic retinopathy can cause poor vision and even blindness since high glucose has been evidenced to weaken retinal capillary leading to leakage of blood into the surrounding space. Besides, high glucose may induce glycosylation of proteins resulting in the loss of their biological functions as well as the generation of reactive oxygen species called glycoxidation. However, the detailed molecular mechanisms by which high glucose leads to diabetic retinopathy have not yet to be clarified. In the recent study, a model retinal pigmented epithelium cell line, ARPE-19, grown in mannitol-balanced 5.5 mM, 25 mM and 100 mM D-glucose culture media has been used as a model for proteomic analysis and the changes in protein expression and thiol reactivity were observed with lysine- and cysteine-labeling 2D-DIGE and MALDI-TOF mass spectrometry. Our proteomic analysis revealed that 56 identified proteins showed significant changes in protein expression, and 33 in thiol reactivity. Moreover, the results revealed that 55 identified proteins showed significant changes in protein expression. Many proteins that are known to be involved in signal transduction, gene regulation and transport were shown significant changes under high glucose conditions. In addition, the thiol-reactivity of proteins involving metabolism, transport and cells survival were altered by high glucose. Additionally, these secreted proteins mainly function in cytoskeleton-associated adhesion / junction (such as galectin-3-binding protein) and transport (multidrug resistance-associated protein 1). Additionally, the identified secreted markers including MPP2, haptoglobin and cathepsin D were further validated in plasma samples coming from type 2 diabetic patients with retinopathy and healthy donors.To sum up, we report a comprehensive retinal cell-based proteomic approach for the identification of potential expression and redox-associated retinal markers-induced by high glucose conditions. Furthermore, such proteins might further validate with clinical samples and provide as potential targets for the prognosis and diagnosis of diabetic retinopathy. PROJECT II Placenta Proteome Analysis from Down Syndrome Pregnancies for Biomarker Discovery Down syndrome is one of the most frequent chromosomal disorders, with prevalence approximately 1/500 to 1/800, depending on the maternal age distribution of the pregnant population. However, few reliable protein biomarkers have been used in diagnosis of this disease. Recent progresses in quantitative proteomics have offered opportunities to discover biomarkers for tracking the progression and for understanding the molecular mechanisms of Down syndrome. In present study, placental samples were analyzed by fluorescence two-dimensional differential gel electrophoresis (2D-DIGE) and differentially expressed proteins were identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Totally, 101 proteins have been firmly identified representing 80 unique gene products. These proteins mainly functioned in cytoskeleton structure and regulation (such as vimentin and Profilin-1). Additionally, our quantitative proteomic approach has identified numerous previous reported Down syndrome markers such as serum amyloid P-component. On the contrary, we have presented several Down syndrome biomarkers including galectin-1, ataxin-3 and sprouty-related EVH1 domain-containing protein 2 (SPRED2) which have not been reported and may be associated with the progression and development of the disease. In summary, we report a comprehensive placenta-based proteomic approach for the identification of potential biomarkers for Down syndrome. The potential of utilizing these markers for prognosis and screen of Down syndrome warrants further investigations.