Differential chemokine expression in tubular cells in response to urinary proteins from patients with nephrotic syndrome.
OBJECTIVE
Comparison of urine proteins in idiopathic minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) patients has been previously conducted, but the relationship between the severity of tubular injury and the composition of urine proteins in various kidney diseases is unknown. This study aimed to investigate the chemokine expression in human tubular cells in response to urine proteins from patients with nephrotic syndrome.


METHODS
Urine proteins collected from patients with MCD or FSGS were extracted by ultrafiltration and coincubated with HK-2 cells. The expression of the RANTES and MIF genes and the activation of p38 and extracellular regulated kinase were determined.


RESULTS
The urine proteins from both MCD and FSGS patients contained a primary band of proteins with Mr of approximately 62 kDa. The major cytokines present in urine proteins from MCD and FSGS patients were IL-6 and IL-8, while IL-1beta, IL-10, IL-12p70 and TNF-alpha were only detectable. We observed time- and dose-dependent increases in RANTES and MIF expression with urine protein treatment in HK-2 cells. The urine proteins from FSGS patients induced a higher expression of these two chemokines in HK-2 cells compared to the urine proteins from MCD patients. ERK and p38 were activated by urine proteins from either MCD or FSGS patients. Pretreatment with SB203580 or PD98059 abolished the increase in RANTES and MIF expression induced by urine proteins from FSGS patients, while only SB203580 suppressed the high expression induced by urine proteins from MCD patients.


CONCLUSIONS
These findings indicate that the urine proteins from MCD and FSGS patients induce a differential expression of RANTES and MIF in tubular cells through distinct activation of MAPK-related signaling pathways.
Huang
Zhao
Z
Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong, PR China.
Wen
Qiong
Q
Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong, PR China.
Zhou
Shu-Feng
SF
Division of Chinese Medicine, School of Health Sciences, WHO Collaborating Centre for Traditional Medicine, RMIT University, Vic., Australia.
Yu
Xue-Qing
XQ
Department of Nephrology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong, PR China. Electronic address: yuxq@mail.sysu.edu.cn.
D002460:Cell Line; D018946:Chemokine CCL5 / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology / Q000652:urine; D018925:Chemokines / Q000096:biosynthesis* / Q000235:genetics / Q000652:urine*; D004591:Electrophoresis, Polyacrylamide Gel; D020869:Gene Expression Profiling; D005923:Glomerulosclerosis, Focal Segmental / Q000378:metabolism; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology / Q000652:urine; D007687:Kidney Tubules, Proximal / Q000166:cytology* / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology; D008263:Macrophage Migration-Inhibitory Factors / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology / Q000652:urine; D009404:Nephrotic Syndrome / Q000652:urine*; D011507:Proteinuria / Q000378:metabolism* / Q000652:urine*
D018946:Chemokine CCL5; D018925:Chemokines; D008263:Macrophage Migration-Inhibitory Factors; D019746:Intramolecular Oxidoreductases; C515598:MIF protein, human