Differential proteomic analysis of renal tissue in lupus nephritis using iTRAQ reagent technology

In clinical practice, it is difficult to monitor the repeating relapse in patients suffering from systemic lupus erythematosus (SLE), who usually associated with some potential complications, for example, lupus nephritis (LN), repetition renal biopsy is necessary to determine LN flares. To identify and quantify the total proteins in renal tissue of LN patients, isobaric tags for relative and absolute quantification (iTRAQ) technology was performed. Eight-plex iTRAQ coupled with multiple chromatographic fractionation and tandem mass spectrometry were used to analyze total proteins in renal tissue of LN patients and healthy controls. Proteins were identified by mascot, which expressed differentially were noted. A total of 490 distinct proteins were identified, 113 proteins were up-regulation or down-regulation at one fold or more alteration in levels. Among of them, there was significant deviation of four proteins between our present iTRAQ study, which are up-regulated heterogeneous nuclear ribonucleoprotein (hnRNP-), Annexins and down-regulated Argininosuccinate synthetase (ASS), aldolase. iTRAQ-based quantitative proteomic technology is efficiently applicable for identification and relative quantitation of proteome of renal tissue. Differentially expressed proteome profiles of LN patients are determined. And further investigation is necessary using large cohorts of patient samples with long-term clinical follow-up data, to assess the usefulness of the pathogenesis and novel biomarker candidates of LN, which may develop a new way for diagnosis of LN.