Starvation Induces Phase-Specific Changes in the Proteome of Mouse Small Intestine

Food deprivation results in metabolic, structural, and functional changes in the small intestine that influences gut mucosal integrity, epithelial cell proliferation, mucin synthesis, and other processes. The underlying mechanisms are still unclear, which lead to the study of molecular effects of short-term and long-term starvation in the intestine of mice. A comparative proteomics approach, combining two-dimensional gel electrophoresis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, was used to identify intestinal proteins whose expression is changed under different starvation conditions (0, 12, 24, and 72 h). In total, the expression levels of 80 protein spots changed significantly between the different groups. The results demonstrate that after 12 h of starvation, mainly proteins involved in glycolysis and energy metabolism show decreased expression levels. Starvation for 24 h results in a down-regulation of proteins involved in protein synthesis and amino acid metabolism. Simultaneously, proteins with a protective role, e.g., reg I and II, glutathione peroxidase 3, and carbonic anhydrase 3, are clearly up-regulated. The last starvation phase (72 h) is characterized by increased ezrin expression, which may enhance villus morphogenesis critical for survival. Together, these results provide novel insights in the intestinal starvation response and may contribute to improved nutritional support during conditions characterized by malnutrition

Weight loss-induced stress in subcutaneous adipose tissue is related to weight regain

Initial successful weight loss is often followed by weight regain after the dietary intervention. Compared with lean people, cellular stress in adipose tissue is increased in obese subjects. However, the relation between cellular stress and the risk for weight regain after weight loss is unclear. Therefore, we determined the expression levels of stress proteins during weight loss and weight maintenance in relation to weight regain. In vivo findings were compared with results from in vitro cultured human Simpson-Golabi-Behmel syndrome (SGBS) adipocytes. In total, eighteen healthy subjects underwent an 8-week diet programme with a 10-month follow-up. Participants were categorised as weight maintainers or weight regainers (WR) depending on their weight changes during the intervention. Abdominal subcutaneous adipose tissue biopsies were obtained before and after the diet and after the follow-up. In vitro differentiated SGBS adipocytes were starved for 96 h with low (0.55 mm) glucose. Levels of stress proteins were determined by Western blotting. WR showed increased expressions of beta-actin, calnexin, heat shock protein (HSP) 27, HSP60 and HSP70. Changes of beta-actin, HSP27 and HSP70 are linked to HSP60, a proposed key factor in weight regain after weight loss. SGBS adipocytes showed increased levels of beta-actin and HSP60 after 96 h of glucose restriction. The increased level of cellular stress proteins in the adipose tissue of WR probably resides in the adipocytes as shown by in vitro experiments. Cellular stress accumulated in adipose tissue during weight loss may be a risk factor for weight regain

Potential biomarkers for diagnosis of sarcoidosis using proteomics in serum

SummaryBackgroundSarcoidosis is a multi-systemic inflammatory disorder, which affects the lungs in 90% of the cases. The main pathologic feature is chronic inflammation resulting in non-caseating granuloma formation. Until now there is no satisfying biomarker for diagnosis or prognosis of sarcoidosis. This study is focused on the detection of potential biomarkers in serum for the diagnosis of sarcoidosis using surface-enhanced laser desorption ionization-time of flight-mass spectrometry (SELDI-TOF-MS).MethodsFor detection of potential biomarkers, protein profiles of anion exchange fractionated serum of 35 sarcoidosis patients and 35 healthy controls were compared using SELDI-TOF-MS. Sensitivities and specificities of the potential biomarkers obtained with SELDI-TOF-MS, generated with decision tree algorithm, were compared to the conventional markers angiotensin converting enzyme (ACE) and soluble interleukin-2 receptor (sIL-2R).ResultsOptimal classification was achieved with metal affinity binding arrays. A single marker with a mass-to-charge (m/z) value of 11,955 resulted in a sensitivity and specificity of 86% and 63%, respectively. A multimarker approach of two peaks, m/z values of 11,734 and 17,377, resulted in a sensitivity and specificity of 74% and 71%, respectively. These sensitivities and specificities were higher compared to measurements of ACE and sIL-2R. Identification of the peak at m/z 17,377 resulted in the α-2chain of haptoglobin.ConclusionsThis study acts as a proof-of-principle for the use of SELDI-TOF-MS in the detection of new biomarkers for sarcoidosis. The peak of the multimarker at m/z 17,377 was identified as the α-2chain of haptoglobin

Validation, optimisation, and application data in support of the development of a targeted selected ion monitoring assay for degraded cardiac troponin T

AbstractCardiac troponin T (cTnT) fragmentation in human serum was investigated using a newly developed targeted selected ion monitoring assay, as described in the accompanying article: “Development of a targeted selected ion monitoring assay for the elucidation of protease induced structural changes in cardiac troponin T” [1]. This article presents data describing aspects of the validation and optimisation of this assay. The data consists of several figures, an excel file containing the results of a sequence identity search, and a description of the raw mass spectrometry (MS) data files, deposited in the ProteomeXchange repository with id PRIDE: PXD003187

2D-electrophoresis and multiplex immunoassay proteomic analysis of different body fluids and cellular components reveal known and novel markers for extended fasting

Proteomic technologies applied for profiling human biofluids and blood cells are considered to reveal new biomarkers of exposure or provide insights into novel mechanisms of adaptation