We present a method to preserve and process urine proteins for proteomic analysis in a filter aided sample preparation (FASP) format. The method combines concentration of urine proteins in ultrafiltration devices, their thermal stabilization, allowing long term storage of the samples, and filter aided sample preparation. Proteomes of four different urines were preserved during 48 h and 6 months using (i) the classic freeze preservation at -20 °C, (ii) snap-heated freeze-free preservation at laboratory temperature (20 °C) and (iii) snap-heated preservation at -60 °C. The three storage methods can effetely preserve the urine proteome for at least 6 months without significant alterations. Abundances of more than 500 proteins and specially 24 selected -cleared or -approved protein assayed in serum or plasma were found similar within the three preservation methods assessed. The new method here proposed dramatically simplifies the conditions for preserving the urine proteome for biobanks in terms of space and storage, including lowering the risks of sample degradation caused by misfunction of the freezer. Furthermore, the shipping of large number of samples can be made without the need of freezing. The application of the FASP format to isolate and preserve the proteins facilitates long-term storage and processing of proteome of urine samples.
Keywords: Filter-aided sample preparation; Heat stabilization; Label-free quantitative mass spectrometry; Room temperature urine preservation; Urine proteomics.
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