A suppressive effect of cyclosporine A on replication and noncoding control region activation of polyomavirus BK virus.
BACKGROUND
The effect of cyclosporine A (CsA) on polyomavirus BK virus (BKV) replication remains unclear. The aim of this in vitro study was to investigate the effect of CsA on BKV replication in human uroepithelial cells.


METHODS
After infection of a human renal proximal tubular cell line, HK-2 with BKV, BKV viral load in the presence of CsA was assessed by real-time polymerase chain reaction. The BKV large T-antigen (LTag) expression was measured by Western blot analysis. The BKV early promoter activity was determined by measuring luciferase activity of the BKV noncoding control region luciferase reporter. The BKV LTag expression in a human bladder carcinoma cell line, T24, was assessed by immunofluorescence.


RESULTS
The results demonstrated that the increased levels of BKV LTag and viral protein 1 transcripts measured by real-time polymerase chain reaction were suppressed by CsA in a dose-dependent manner (0.5-4 microg/mL). Western blot analysis also showed that CsA inhibited BKV LTag expression. In addition, the activity of the BKV early promoter, which was enhanced by BKV LTag overexpression, was abrogated by CsA. Finally, the suppressive effect of CsA on BKV replication was also shown in T24 cells as CsA reduced immunofluorescent staining of BKV LTag in these cells.


CONCLUSIONS
This in vitro study indicates that CsA suppresses BKV replication in human proximal renal tubular cells and uroepithelial cells of the urinary bladder and inhibits the BKV-LTag-regulated increase in early promoter activity.
Department of Nephrology, Chang Gung Memorial Hospital, Taipei, Taiwan.
Yi-Jung
YJ
Li
Cheng-Hao
CH
Weng
Wen-Chi
WC
Lai
Hsin-Hsu
HH
Wu
Yung-Chang
YC
Chen
Cheng-Chieh
CC
Hung
Chih-Wei
CW
Yang
Ya-Chung
YC
Tian
D000957:Antigens, Viral, Tumor / Q000235:genetics; D001739:BK Virus / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity / Q000502:physiology*; D002460:Cell Line; D016572:Cyclosporine / Q000494:pharmacology*; D017931:DNA Primers; D018076:DNA, Complementary / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D005784:Gene Amplification; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics; D006801:Humans; D016133:Polymerase Chain Reaction; D015678:Viral Structural Proteins / Q000235:genetics; D014775:Virus Activation / Q000187:drug effects*; D014779:Virus Replication / Q000187:drug effects*
D000957:Antigens, Viral, Tumor; D017931:DNA Primers; D018076:DNA, Complementary; D004279:DNA, Viral; D015678:Viral Structural Proteins; D016572:Cyclosporine; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases