| Summary: | 博士 === 國防醫學院 === 醫學科學研究所 === 99 === Focal segmental glomerulosclerosis (FSGS) is a common chronic nephropathy which occurs during both childhood and adulthood. About one-third of FSGS patients finally develop end-stage renal failure within a decade. Since the pathogenesis of FSGS is poorly understood, there is still no best strategy yet for physicians to treat FSGS patients. In addition, because of lack of urinary biomarkers for FSGS, diagnosis and prognosis of this disease still rely mainly on renal biopsy, which is an invasive procedure that can cause damage. The purpose of this study was to screen for proteins which play mechanistical roles in FSGS development and / or serve as biomarkers for FSGS diagnosis and prognosis.
This study contains a series of experiments, which can be divided into three parts. First, a 2-DE gel-based proteomic approach was used to identify potential urinary biomarkers of FSGS at the pre-sclerotic stage in an adriamycin-induced FSGS mouse model. Second, biochemical, immunohistochemical, and immunocytochemical methods were used to check the expression of Rab23 and various hedgehog signaling pathway genes at different severity stages of FSGS. Third, the pathophysiological roles of Rab23 were explored by performing proteomics and systems biology analyses on cultured mesangial cells with knockdown or overexpression of Rab23.
We successfully established FSGS mouse model by single injection of adriamycin in BALB/c mice. Using this model, we identified a novel protein Rab23 and some urinary protein biomarkers, the elevation of which appears before the development of glomerular sclerosis. Elevations of Rab23, which is one of the identified proteins, can be detected in the urine, but not in the serum, in the FSGS mice. In addition, Rab23 and hedgehog signaling pathway genes were constitutively expressed in normal conditions, and were significantly up-regulated in mesangial cells at the FSGS states. The Knockdown or overexpression of Rab23 not only affected the expression of collagen, but also impacted on expression of a variety of proteins in cultured mesangial cells. Bioinformatics analysis of the identified proteins further revealed the pathophysiological roles of Rab23, including G-protein signal transduction, transcription modulation, RNA stabilization, protein synthesis and degradation, cytoskeleton reorganization, anti-oxidation and detoxification, circadian rhythm regulation and phagocytosis.
Taken together, these data indicate that Rab23 could serve as a potential non-invasive biomarker for FSGS development. The proteomics and bioinformatics analyses revealed that Rab23 can impact on multiple biological networks in mesangial cells, and this bionetwork data can give an insight into pathophysiological roles of Rab23 in mesangial cells, and can shed light on the mechanism underlying FSGS.
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