Senescence marker protein 30 in acute liver failure: validation of a mass spectrometry proteomics assay.
BACKGROUND
Our previous proteomic study showed that the senescence marker protein (SMP30) is selectively present in the plasma of a murine model of acute liver failure (ALF). The aim of this study was to validate this SMP30 expression in the plasma and liver tissues of mice and humans with ALF.


METHODS
After the proteomic analysis of plasma from a murine model of D-galactosamine/lipopolysaccharide (GalN/LPS)-induced ALF by two-dimensional electrophoresis (2-DE) and mass spectrometry, the expression levels of SMP30 in the plasma and liver tissues were validated by western blot and RT-PCR analyses. These results were then confirmed in plasma samples from humans.


RESULTS
These data validate the results of 2-DE, and western blot showed that SMP30 protein levels were only elevated in the plasma of ALF mice. Further analysis revealed that GalN/LPS induced the downregulation of SMP30 protein levels in liver tissues (by approximately 25% and 16% in the GalN/LPS-treated mice and in the treated mice that survived, respectively; P < 0.01). Hepatic SMP30 mRNA levels decreased by about 90% only in the mice that survived the GalN/LPS treatment. Importantly, plasma obtained from patients with ALF also contained higher levels of SMP30, about (3.65 +/- 0.34) times those observed in healthy volunteers.


CONCLUSIONS
This study shows that SMP30 is not only a potential biomarker for the diagnosis and even prognosis of ALF. It also plays a very important role in a self-protective mechanism in survival and participates in the pathophysiological processes of ALF.
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Sa
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Peking University People's Hospital, Peking University Hepatology Institute, Beijing 100044, PR China. vsa@sina.com
Wang
Jiang-hua
JH
Liu
Feng
F
Gao
Yan
Y
Fei
Ran
R
Du
Shao-cai
SC
Wei
Lai
L
D000818:Animals; D015415:Biomarkers / Q000097:blood; D002135:Calcium-Binding Proteins / Q000097:blood* / Q000302:isolation & purification*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000097:blood* / Q000302:isolation & purification*; D008099:Liver / Q000737:chemistry / Q000378:metabolism; D017114:Liver Failure, Acute / Q000097:blood* / Q000175:diagnosis; D008297:Male; D013058:Mass Spectrometry / Q000592:standards*; D051379:Mice; D008807:Mice, Inbred BALB C; D011379:Prognosis; D040901:Proteomics / Q000295:instrumentation* / Q000592:standards
D015415:Biomarkers; D002135:Calcium-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; C513323:RGN protein, human; C513324:Rgn protein, mouse