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BACKGROUND: Hypertensive nephrosclerosis is one of the most frequent causes of chronic kidney failure. Proteome analysis potentially improves the pathophysiological understanding and diagnostic precision of this disorder. In the present exploratory study, we investigated experimental nephrosclerosis in the two-kidney, one-clip (2K1C) hypertensive rat model. METHODS: The renal cortex proteome from juxtamedullary cortex and outer cortex of 2K1C male Wistar-Hannover rats (n = 4) was compared with the sham-operated controls (n = 6), using mass spectrometry-based quantitative proteomics. We combined a high abundant plasma protein depletion strategy with an extended liquid chromatographic gradient to improve peptide and protein identification. Immunohistology was used for independent confirmation of abundance. RESULTS: We identified 1724 proteins, of which 1434 were quantified with at least two unique peptides. Comparative proteomics revealed 608 proteins, including the platelet-derived growth factor receptor-β signalling pathway, with different abundances between the non-clipped kidney of hypertensive 2K1C rats and the corresponding kidney of the normotensive controls (P < 0.05, absolute fold change ≥1.5). Among the most significantly altered proteins in the whole cortex were periostin, transgelin, and creatine kinase B-type. Relative abundance of periostin alone allowed clear classification of 2K1C and controls. Enrichment of periostin in 2K1C rats was verified by immunohistology, showing positivity especially around the fibrotic vessels. CONCLUSION: The proteome is altered in hypertension-induced kidney damage. We propose periostin, especially in combination with transgelin and creatine kinase B-type, as possible proteomic classifier to distinguish hypertensive nephrosclerosis from the normal tissue. This classifier needs to be further validated with respect to early diagnosis of fibrosis, prognosis, and its potential as a novel molecular target for pharmacological

Multiple sclerosis (MS) is a chronic inflammatory disease of the CNS with unknown cause. Proteins with different abundance in the cerebrospinal fluid (CSF) from relapsing-remitting MS (RRMS) patients and neurological controls could give novel insight to the MS pathogenesis and be used to improve diagnosis, predict prognosis and disease course, and guide in therapy decisions. We combined iTRAQ labeling and Orbitrap mass spectrometry to discover proteins with different CSF abundance between six RRMS patients and 18 neurological disease controls. From 777 quantified proteins seven were selected as biomarker candidates, namely chitinase-3-like protein 1, secretogranin-1 (Sg1), cerebellin-1, neuroserpin, cell surface glycoprotein MUC18, testican-2 and glutamate receptor 4. An independent sample set of 13 early-MS patients, 13 RRMS patients and 13 neurological controls was used in a multiple reaction monitoring verification study. We found the intracellular calcium binding protein Sg1 to be increased in early-MS patients compared to RRMS and neurological controls. Sg1 should be included in further studies to elucidate its role in the early phases of MS pathogenesis and its potential as a biomarker for this disease. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In the present study, we aimed to discover cerebrospinal fluid (CSF) proteins with significant abundance difference between early multiple sclerosis patients and controls, and do an initial verification of these proteins using selected reaction monitoring (SRM). iTRAQ and Orbitrap MS were used to compare the CSF proteome of patients with clinically isolated syndrome (CIS) (n=5), patients with relapsing-remitting multiple sclerosis that had CIS at the time of lumbar puncture (n=5), and controls with other inflammatory neurological disease (n=5). Of more than 1200 identified proteins, five proteins were identified with significant abundance difference between the patients and controls. In the initial verification using SRM we analyzed a larger patient and control cohort (n=132) and also included proteins reported as differentially abundant in multiple sclerosis in the literature. We found significant abundance difference for 11 proteins after verification, of which the five proteins alpha-1-antichymotrypsin, contactin-1, apolipoprotein D, clusterin, and kallikrein-6 were significantly differentially abundant in several of the group comparisons. This initial study form the basis for further biomarker verification studies in even larger sample cohorts, to determine if these proteins have relevance as diagnostic or prognostic biomarkers for multiple sclerosis.