Proteomic profiling of urinary protein excretion in the factor H-deficient mouse.
BACKGROUND
Since the 1970s a variety of experimental techniques have been employed in an attempt to identify urinary biomarkers of renal injury. While these approaches have met with some success, modern proteomic tools now permit broad based high-throughput analysis of the urinary proteome.


METHODS
Using the ICAT isotopic labeling based LC/MS/MS approach, comparative urinary protein profiling was performed in a murine model of membranoproliferative glomerulonephritis. Paired samples were analyzed mice with a targeted deletion of the complement regulatory protein factor H (FH-/-) and control mice.


RESULTS
25 distinct urinary proteins were identified of which 7 were differentially expressed in the FH-/- mice. Two proteins were markedly altered in the urine of FH-/- mice compared to controls: uromodulin (5.5-fold lower) and the MHC class II molecule H2e (8.6-fold higher). Differential expression was confirmed by Western blot and RT-PCR. Immunofluorescent staining demonstrated a marked increased expression of H2e and a reduction of uromodulin expression in the tubular epithelium of FH-/- mice.


CONCLUSIONS
These findings provide insight into early complement-dependent alterations in tubular protein expression which may play critical roles in the development of tubulointerstitial disease, and provide experimental support for the use of urinary proteomic profiling in murine models of renal injury.
The Brown Foundation Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, Texas 77030, USA. michael.c.braun@uth.tmc.edu
Michael C
MC
Braun
Li
L
Li
Baozhen
B
Ke
William P
WP
Dubinsky
Mathew C
MC
Pickering
Jui-Yoa
JY
Chang
D000818:Animals; D017242:Complement Factor H / Q000172:deficiency* / Q000235:genetics; D003433:Crosses, Genetic; D004195:Disease Models, Animal; D020869:Gene Expression Profiling / Q000379:methods*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011507:Proteinuria / Q000235:genetics / Q000503:physiopathology*; D020543:Proteome / Q000032:analysis*; D040901:Proteomics / Q000379:methods*; D013997:Time Factors
D020543:Proteome; D017242:Complement Factor H