Left-right determination factor is down-regulated in fibrotic renal tissue of human hydronephrosis.
OBJECTIVE
• To compare the expressions of common fibrosis-relevant genes in hydronephrosis-induced fibrotic renal tissues and normal human renal tissues, thereby providing insights into the cellular and molecular mechanisms of renal fibrosis resulting from hydronephrosis.


METHODS
• A total of 12 extensively fibrotic renal tissue samples from patients with hydronephrosis (H-group) and six normal renal tissue samples from patients who underwent nephrectomy for renal cell carcinoma (N-group), along with their clinical data, were collected at Renmin Hospital of Wuhan University in China between October 2005 and August 2007. • These tissue samples were compared for their transforming growth factor-β (TGF-β)/bone morphogenetic protein (BMP) pathway-related gene profiles using a real-time polymerase chain reaction (PCR) microarray. • Subsequently, reverse transcriptase-PCR assays were used to validate the expression changes of left-right determination factor (LEFTY), a gene of interest, at the mRNA level. • The different expression of LEFTY at the protein level was confirmed by western blotting and immunohistochemistry assays.


RESULTS
• The results showed that 49 genes were differently expressed in fibrotic renal tissues relative to normal control tissues. Among these genes, 25 were up-regulated and 24 were down-regulated. • LEFTY-B, one of the most markedly altered genes, was down-regulated 13.55-fold compared with N-group tissues. • RT-PCR showed that the LEFTY-A (6.05-fold down-regulated, P < 0.001) and LEFTY-B (12.5-fold down-regulated, P < 0.001) genes, two members of the LEFTY family in human tissues, were both significantly down-regulated in H-group tissues. • Similarly, down-regulations of LEFTY-A (0.25-fold vs N-group, P < 0.001) and LEFTY-B (0.20-fold vs N-group, P < 0.001) proteins were detected by western blotting (P < 0.001). • Immunohistochemical staining showed different distributions of LEFTY in the two tissue samples, and quantitative image analyses confirmed that LEFTY protein expression was lower in H-group tissues than in N-group tissues (P < 0.001).


CONCLUSIONS
• The gene and protein expressions of LEFTY were found to be down-regulated in extensively fibrotic renal tissues induced by hydronephrosis. • LEFTY may represent an ideal candidate for a therapeutic target for renal fibrosis.
Yao
Yi
Y
Oncology Center, Department of Urology, Renmin Hospital of Wuhan University and State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China.
Zhang
Jie
J
Ye
Da-Fu
DF
Tan
Da-Qing
DQ
Peng
Jian-Ping
JP
Xie
Mei
M
Fang
Li
L
D000328:Adult; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D015536:Down-Regulation / Q000502:physiology*; D005260:Female; D005355:Fibrosis; D006801:Humans; D006869:Hydronephrosis / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D007150:Immunohistochemistry; D007668:Kidney / Q000473:pathology*; D055458:Left-Right Determination Factors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D016133:Polymerase Chain Reaction; D016212:Transforming Growth Factor beta / Q000378:metabolism
D019485:Bone Morphogenetic Proteins; D055458:Left-Right Determination Factors; D016212:Transforming Growth Factor beta