Biotech Support Group reports on a recent research article which describes the simplicity and efficiency of their proteomic sample preparation technology for albumin depletion. Urine exosome isolation via ultracentrifugation, followed by albumin depletion provides researchers with knowledge of renal regulation and could lead to the identification of biomarkers for diabetic nephropathy and diabetic mellitus. By removing albumin using AlbuSorbTM, the authors identified more urinary proteins such as flotillin-2, lamp-1, PODXL, tsg-101 from exosome fractions of urine samples.
In brief, the article which appears in the Journal of Proteomics, states that diabetes mellitus leads to diabetic nephropathy (DN), ultimately causing end- stage renal disease (ESRD). So discovery of candidate biomarkers which identify the pathophysiological mechanism of DN remain important. Identification of such biomarker proteins from diabetic nephropathy (DN) and healthy human urine samples is challenged by the high abundance proteins present in urine, especially albumin and Tamm-Horsfall protein. Secreted microvesicles known as exosomes are linked to antigen expression, RNA and protein transport. Exosomes extracted from urine samples could become a rich source of urinary biomarkers, and may supplement serum creatinine and albumin excretion, for disease staging and clinical intervention. In this article, exosome isolation via ultracentrifugation, dithiothreitol (DTT) treatment, and albumin depletion of precipitated exosome fractions is described. Authors Zubiri et al, cite AlbuSorbTM for albumin depletion and further describe proteomic workflows for biomarker discovery from isolated urine exosomes. Subsequent LC-MS/MS and selected reaction monitoring (SRM) of urine exosome protein content from diabetic and healthy controls were analyzed. The research cites AMBP, MLL3, VDAC1 as proteins in urinary exosomes of diabetic nephropathy patients.
“This article further validates our unique surface technology, not based on antibodies or engineered bio- ligands, as being a highly selective and efficient method for the depletion of albumin from any biological source. I am delighted to see that such efficiencies lead to the enhanced contribution of proteomics to understand and treat disease.” states Swapan Roy, Ph.D., President and Founder of Biotech Support Group.
Characteristics of AlbuSorbTM
Removes >90% albumin from 30 mg albumin/ml sample
- Affinity-type equivalence, virtually no cross-reactivity with other proteins
- Bind and elute procedure – simply weigh powder, condition the sample, centrifuge and/or filter, and recover the albumin depleted serum
- Economical new surface technology, not based on biologically derived ligands
- Mild conditions maintain tertiary structure of proteins and simple transfer to secondary analysis
- The albumin depleted filtrate retains all enzymatic and biological activity
- Tissue and species agnostic
- The flow through fraction is compatible with LC-MS, activity based protein profiling and all proteomic analyses.
Diabetic nephropathy induces changes in the proteome of human urinary exosomes as revealed by label-free comparative analysis, Authors: Zubiri, Irene, Maria Posada-Ayala, Aroa Sanz-Maroto, Enrique Calvo, Marta Martin-Lorenzo, Laura Gonzalez-Calero, Fernando de la Cuesta et al. Journal of Proteomics (2014) doi.org/10.1016/j.jprot.2013.10.037