Comparative proteome analysis of splenic lymphocytes in long-term high-fat diet and dietary supplement with lipoic acid mice

The Immunomodulatory Effect of Alpha-Lipoic Acid in Autoimmune Diseases

Αlpha-lipoic acid is a naturally occurring antioxidant in human body and has been widely used as an antioxidant clinically. Accumulating evidences suggested that α-lipoic acid might have immunomodulatory effects on both adaptive and innate immune systems. This review focuses on the evidences and potential targets involved in the immunomodulatory effects of α-lipoic acid. It highlights the fact that α-lipoic acid may have beneficial effects in autoimmune diseases once the immunomodulatory effects can be confirmed by further investigation.

Health Risks of Food Oxidation

The impact of dietary habits on our health is indisputable. Consumer's concern on aging and age-related diseases challenges scientists to underline the potential role of food on the extension and guarantee of lifespan and healthspan. While some dietary components and habits are generally regarded as beneficial for our health, some others are being found to exert potential toxic effects and hence, contribute to the onset of particular health disorders. Among the latter, lipid and protein oxidation products formed during food production, storage, processing, and culinary preparation have been recently identified as potentially harmful to humans. Upon intake, food components are further degraded and oxidized during the subsequent digestion phases and the pool of compounds formed in the lumen is in close contact with the lamina propria of the intestines. Some of these oxidation products have been found to promote inflammatory conditions in the gut (i.e., bowel diseases) and are also reasonably linked to the onset of carcinogenic processes. Upon intestinal uptake, some species are distributed by the bloodstream causing an increase in oxidative stress markers and impairment of certain physiological processes through alteration of specific gene expression pathways. This chapter summarizes the most recent discoveries on this topic with particular stress on challenges that we face in the near future: understanding the molecular basis of disease, the suitability of using living animals vs in vitro model systems and the necessity of using massive genomic techniques and versatile mass spectrometric technology.

Effect of high-fat diet on hepatic proteomics of hamsters

A high-fat diet contributes to the etiology of metabolic diseases. As the liver plays a crucial role in metabolism, an insight into the hepatic proteomics will help to illustrate the physiological effect of a high-fat diet. Fourteen nine-week old male Syrian hamsters were maintained on either control (C) or high-fat (HF) diets (0.2% cholesterol +22% fat) for 8 weeks. Hamsters were chosen because they show close similarity to human lipid metabolism. At the end of study, blood and livers were collected for analysis. Liver proteins were fractionated by electrophoresis, digested by trypsin, and then separated by label-free nano-LC/MS/MS. The TurboSequest algorithm was used to identify the peptide sequences against the hamster database in Universal Proteins Resource Knowledgebase (UniProt). The results indicate that 1191 hepatic proteins were identified and 135 of them were expressed differentially in the high-fat group (p < 0.05). Some of these 135 proteins that involve in metabolic diseases were further validated by Western blotting. The animals maintained on the high-fat diet had significantly (p < 0.05) higher serum triglyceride, cholesterol, aspartate aminotransferase (AST), alanine aminotransferase (ALT), and uric acid. Animals consuming a high-fat diet also had significantly (p < 0.05) more accumulation of triglyceride and cholesterol in livers. Xanthine dehydrogenase (XDH), which plays an important role in uric acid synthesis, was up-regulated by the high-fat diet (p < 0.05). The α-subunit of hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase (HADHA), which catalyzes the second and third reactions of β-oxidation, was down-regulated by the high-fat diet (p < 0.05). Aconitate hydratase 2 (ACO2), which catalyzes the conversion of citrate to isocitrate in TCA cycle, was down-regulated in animals of the high-fat group (p < 0.05). Inflammatory markers annexin A3 (ANXA3) and annexin A5 (ANXA5) were up-regulated by the high-fat diet (p < 0.05). Moreover, enzymes involved in the urea cycle were suppressed by high-fat diet, including carbamoyl phosphate synthase 1 (CPS1), ornithine transcarbamoylase (OTC), argininosuccinate synthase (ASS), argininosuccinate lyase (ASL), and arginase 1 (ARG 1). Post-translational modifications (PTM) of ANXA3, ANXA5, and XDH were also analyzed. A set of differentially expressed proteins were identified as molecular markers for elucidating the pathological mechanism of high-fat diet.