Discovery of SERPINA3 as a candidate urinary biomarker of lupus nephritis activity

Abstract

Objectives. We used an unbiased proteomics approach to identify candidate urine biomarkers (CUBMs) predictive of LN chronicity and pursued their validation in a larger cohort.Methods. In this cross-sectional pilot study, we selected urine collected at kidney biopsy from 20 children with varying levels of LN damage (discovery cohort) and performed proteomic analysis using isobaric tags for relative and absolute quantification (iTRAQ). We identified differentially excreted proteins based on degree of LN chronicity and sought to distinguish markers exhibiting different relative expression patterns using hierarchically clustered log10-normalized relative abundance data with linked and distinct functions by biological network analyses. For each CUBM, we performed specific ELISAs on urine from a validation cohort (n = 41) and analysis of variance to detect differences between LN chronicity, with LN activity adjustment. We evaluated for CUBM expression in LN biopsies with immunohistochemistry.Results. iTRAQ detected 112 proteins in urine from the discovery cohort, 51 quantifiable in all replicates. Simple analysis of variance revealed four differentially expressed, chronicity-correlated proteins (P-values < 0.05). Further correlation and network analyses led to selection of seven CUBMs for LN chronicity. In the validation cohort, none of the CUBMs distinguished LN chronicity degree; however, urine SERPINA3 demonstrated a moderate positive correlation with LN histological activity. Immunohistochemistry further demonstrated SERPINA3 staining in proximal tubular epithelial and endothelial cells. Conclusion.We identified SERPINA3, a known inhibitor of neutrophil cathepsin G and angiotensin II production, as a potential urine biomarker to help quantify LN activity.

Multi-level analysis of reproduction in an Antarctic midge identifies female and male accessory gland products that are altered by larval stress and impact progeny viability

“…Based on this initial characterization, gel proteins (6 µg) were run 2 cm into a 1D 4–12% Bis–Tris Invitrogen NuPage gel using MOPS buffer. Lanes were excised, reduced with 10 mM dithiothreitol, alkylated with Iodoacetamide and digested with trypsin according to standard protocol 157 , 158 . The resulting peptides were concentrated with a speed vac centrifuge and resuspended in 0.1% formic acid.…”

The Value of Urinary RBP4 in The Diagnosis of FSGS and other Renal Diseases.

“…Urinary levels of RBP4 increases (even up to 10 4 -fold) in many conditions that affect kidneys e.g. renal glomerular diseases, allograft rejection, acute kidney injury (AKI), lupus nephritis, Fanconi syndrome and diabetes [16,18,19,20). Elevated levels of urinary RBP4 are also observed in tuberculosis, head and neck cancers and bladder cancer [21,22,23].…”

Integrated bioinformatics analysis reveals novel key biomarkers and potential candidate small molecule drugs in diabetic nephropathy

“…A series of DEGs were discovered to be enriched in the GO functions and pathways. SERPINA3 [41], IKZF1 [42], BTK (Bruton tyrosine kinase) [43], C1QA [44], CD1C [45] and CCL13 [46] have a key role in lupus nephritis, but these genes might be liable for advancement of DN. TNFSF14 [47], ITGAL (integrin subunit alpha L) [48], PLAC8 [49], ADRA2A [50], CCL21 [51], ALOX5 [52], CNR2 [53], COL1A1 [54], WNT7A [55], SLAMF1 [56], CD3D [57], LTF (lactotransferrin) [58], MIR27B [59], PDK4 [60], UCN3 [61], PCK1 [62], CEL (carboxyl ester lipase) [63], TRPM6 [64], MTTP (microsomal triglyceride transfer protein) [65], CYP2C8 [66] and CYP3A4 [67] have important role in the progression of type 2 diabetes via in ammation , but these genes might be crucial role in DN progression.…”