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Knockout of microRNA-21 reduces biliary hyperplasia and liver fibrosis in cholestatic bile duct ligated mice

View Article: PubMed Central - PubMed

ABSTRACT

Cholestasis is a condition that leads to chronic hepatobiliary inflammation, fibrosis, and eventually cirrhosis. Many microRNAs (miRs) are known to play a role in fibrosis progression; however, the role of miR-21 during cholestasis remains unknown. Therefore, the aim of this study was to elucidate the role of miR-21 during cholestasis-induced biliary hyperplasia and hepatic fibrosis. Wild-type (WT) and miR21−/− mice underwent sham or bile duct ligation (BDL) for 1 wk, before evaluating liver histology, biliary proliferation, hepatic stellate cell (HSC) activation, fibrotic response, and Smad-7 expression. In vitro, immortalized murine biliary cell lines (IMCL) and human hepatic stellate cell line (hHSC) were treated with either miR-21 inhibitor or control before analyzing proliferation, apoptosis, and fibrotic responses. In vivo, the levels of miR-21 were increased in total liver and cholangiocytes after BDL, and loss of miR-21 decreased the amount of BDL-induced biliary proliferation and intrahepatic biliary mass. Also, loss of miR-21 decreased BDL-induced HSC activation, collagen deposition, and expression of the fibrotic markers TGF-β1 and α-SMA. In vitro, IMCL and hHSCs treated with miR-21 inhibitor displayed decreased proliferation and expression of fibrotic markers and enhanced apoptosis when compared to control treated cells. Furthermore, mice lacking miR-21 show increased Smad-7 expression, which may be driving the decrease in biliary hyperplasia and hepatic fibrosis. During cholestatic injury miR-21 is increased and leads to increased biliary proliferation and hepatic fibrosis. Local modulation of miR-21 may be a therapeutic option for patients with cholestasis.

No MeSH data available.


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Evaluation of miR-21 expression following BDL. Following BDL, miR-21 levels are increased in total liver and isolated cholangiocytes (A, B). In Mdr2−/− mice cholangiocytes have increased miR-21 expression (C). Total liver samples from PSC patients have increased miR-21 levels compared to normal patient samples (D). Data are expressed as means ± SEM. n = 10 reactions in total RNA collected from total liver and cholangiocytes from 8 animals per group for qPCR. n = 3 reactions per sample in total RNA collected from total liver from 1 human control and 1 human PSC sample. *p<0.05 versus Sham WT, WT, Human Control.
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Figure 1: Evaluation of miR-21 expression following BDL. Following BDL, miR-21 levels are increased in total liver and isolated cholangiocytes (A, B). In Mdr2−/− mice cholangiocytes have increased miR-21 expression (C). Total liver samples from PSC patients have increased miR-21 levels compared to normal patient samples (D). Data are expressed as means ± SEM. n = 10 reactions in total RNA collected from total liver and cholangiocytes from 8 animals per group for qPCR. n = 3 reactions per sample in total RNA collected from total liver from 1 human control and 1 human PSC sample. *p<0.05 versus Sham WT, WT, Human Control.

Mentions: Following BDL, there was a significant increase in miR-21 expression in total liver and isolated cholangiocytes when compared to Sham WT mice (Figure 1A–B). miR-21 expression was also increased in cholangiocytes from Mdr2−/− mice 34 when compared to the corresponding WT mice, as well as in total liver extracted from a late stage PSC patient when compared to a normal liver sample. These findings suggest that during cholestatic injury, such as BDL or PSC, miR-21 levels are increased and may contribute to the progression of biliary injury and hepatic fibrosis.


Knockout of microRNA-21 reduces biliary hyperplasia and liver fibrosis in cholestatic bile duct ligated mice
Evaluation of miR-21 expression following BDL. Following BDL, miR-21 levels are increased in total liver and isolated cholangiocytes (A, B). In Mdr2−/− mice cholangiocytes have increased miR-21 expression (C). Total liver samples from PSC patients have increased miR-21 levels compared to normal patient samples (D). Data are expressed as means ± SEM. n = 10 reactions in total RNA collected from total liver and cholangiocytes from 8 animals per group for qPCR. n = 3 reactions per sample in total RNA collected from total liver from 1 human control and 1 human PSC sample. *p<0.05 versus Sham WT, WT, Human Control.
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Related In: Results  -  Collection

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Figure 1: Evaluation of miR-21 expression following BDL. Following BDL, miR-21 levels are increased in total liver and isolated cholangiocytes (A, B). In Mdr2−/− mice cholangiocytes have increased miR-21 expression (C). Total liver samples from PSC patients have increased miR-21 levels compared to normal patient samples (D). Data are expressed as means ± SEM. n = 10 reactions in total RNA collected from total liver and cholangiocytes from 8 animals per group for qPCR. n = 3 reactions per sample in total RNA collected from total liver from 1 human control and 1 human PSC sample. *p<0.05 versus Sham WT, WT, Human Control.
Mentions: Following BDL, there was a significant increase in miR-21 expression in total liver and isolated cholangiocytes when compared to Sham WT mice (Figure 1A–B). miR-21 expression was also increased in cholangiocytes from Mdr2−/− mice 34 when compared to the corresponding WT mice, as well as in total liver extracted from a late stage PSC patient when compared to a normal liver sample. These findings suggest that during cholestatic injury, such as BDL or PSC, miR-21 levels are increased and may contribute to the progression of biliary injury and hepatic fibrosis.

View Article: PubMed Central - PubMed

ABSTRACT

Cholestasis is a condition that leads to chronic hepatobiliary inflammation, fibrosis, and eventually cirrhosis. Many microRNAs (miRs) are known to play a role in fibrosis progression; however, the role of miR-21 during cholestasis remains unknown. Therefore, the aim of this study was to elucidate the role of miR-21 during cholestasis-induced biliary hyperplasia and hepatic fibrosis. Wild-type (WT) and miR21&minus;/&minus; mice underwent sham or bile duct ligation (BDL) for 1 wk, before evaluating liver histology, biliary proliferation, hepatic stellate cell (HSC) activation, fibrotic response, and Smad-7 expression. In vitro, immortalized murine biliary cell lines (IMCL) and human hepatic stellate cell line (hHSC) were treated with either miR-21 inhibitor or control before analyzing proliferation, apoptosis, and fibrotic responses. In vivo, the levels of miR-21 were increased in total liver and cholangiocytes after BDL, and loss of miR-21 decreased the amount of BDL-induced biliary proliferation and intrahepatic biliary mass. Also, loss of miR-21 decreased BDL-induced HSC activation, collagen deposition, and expression of the fibrotic markers TGF-&beta;1 and &alpha;-SMA. In vitro, IMCL and hHSCs treated with miR-21 inhibitor displayed decreased proliferation and expression of fibrotic markers and enhanced apoptosis when compared to control treated cells. Furthermore, mice lacking miR-21 show increased Smad-7 expression, which may be driving the decrease in biliary hyperplasia and hepatic fibrosis. During cholestatic injury miR-21 is increased and leads to increased biliary proliferation and hepatic fibrosis. Local modulation of miR-21 may be a therapeutic option for patients with cholestasis.

No MeSH data available.


Related in: MedlinePlus