Relationship between differential hepatic microRNA expression and decreased hepatic cytochrome P450 3A activity in cirrhosis.
OBJECTIVE
Liver cirrhosis is associated with decreased hepatic cytochrome P4503A (CYP3A) activity but the pathogenesis of this phenomenon is not well elucidated. In this study, we examined if certain microRNAs (miRNA) are associated with decreased hepatic CYP3A activity in cirrhosis.


METHODS
Hepatic CYP3A activity and miRNA microarray expression profiles were measured in cirrhotic (n=28) and normal (n=12) liver tissue. Hepatic CYP3A activity was measured via midazolam hydroxylation in human liver microsomes. Additionally, hepatic CYP3A4 protein concentration and the expression of CYP3A4 mRNA were measured. Analyses were conducted to identify miRNAs which were differentially expressed between two groups but also were significantly associated with lower hepatic CYP3A activity.


RESULTS
Hepatic CYP3A activity in cirrhotic livers was 1.7-fold lower than in the normal livers (0.28 ± 0.06 vs. 0.47 ± 0.07mL* min(-1)*mg protein(-1) (mean ± SEM), P=0.02). Six microRNAs (miR-155, miR-454, miR-582-5p, let-7f-1*, miR-181d, and miR-500) had >1.2-fold increase in cirrhotic livers and also had significant negative correlation with hepatic CYP3A activity (range of r = -0.44 to -0.52, P <0.05). Notably, miR-155, a known regulator of liver inflammation, had the highest fold increase in cirrhotic livers (2.2-fold, P=4.16E-08) and significantly correlated with hepatic CYP3A activity (r=-0.50, P=0.017). The relative expression (2(-ΔΔCt) mean ± SEM) of hepatic CYP3A4 mRNA was significantly higher in cirrhotic livers (21.76 ± 2.65 vs. 5.91 ± 1.29, P=2.04E-07) but their levels did not significantly correlate with hepatic CYP3A activity (r=-0.43, P=0.08).


CONCLUSIONS
The strong association between certain miRNAs, notably miR-155, and lower hepatic CYP3A activity suggest that altered miRNA expression may regulate hepatic CYP3A activity.
Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.
Raj
R
Vuppalanchi
Tiebing
T
Liang
Chirayu Pankaj
CP
Goswami
Rohit
R
Nalamasu
Lang
L
Li
David
D
Jones
Rongrong
R
Wei
Wanqing
W
Liu
Vishal
V
Sarasani
Sarath Chandra
SC
Janga
Naga
N
Chalasani
D020413:3' Untranslated Regions / Q000235:genetics; D003198:Computer Simulation; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism*; D003710:Demography; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D006801:Humans; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008103:Liver Cirrhosis / Q000201:enzymology* / Q000235:genetics*; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D011485:Protein Binding / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism
D020413:3' Untranslated Regions; D035683:MicroRNAs; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D051544:Cytochrome P-450 CYP3A