| 1. |
- Fuchs, C. D., et al.
(författare)
-
Absence of Bsep/Abcb11 attenuates MCD diet-induced hepatic steatosis but aggravates inflammation in mice
- 2020
-
Ingår i: Liver International. - : Wiley. - 1478-3223 .- 1478-3231. ; 40:6, s. 1366-1377
-
Tidskriftsartikel (refereegranskat)abstract
- Background Bile acids (BAs) regulate hepatic lipid metabolism and inflammation. Bile salt export pump (BSEP) KO mice are metabolically preconditioned with a hydrophilic BA composition protecting them from cholestasis. We hypothesize that changes in hepatic BA profile and subsequent changes in BA signalling may critically determine the susceptibility to steatohepatitis. Methods Wild-type (WT) and BSEP KO mice were challenged with methionine choline-deficient (MCD) diet to induce steatohepatitis. Serum biochemistry, lipid profiling as well as intestinal lipid absorption were assessed. Markers of inflammation, fibrosis, lipid and BA metabolism were analysed. Hepatic and faecal BA profile as well as serum levels of the BA synthesis intermediate 7-hydroxy-4-cholesten-3-one (C4) were also investigated. Results Bile salt export pump KO MCD-fed mice developed less steatosis but more inflammation than WT mice. Intestinal neutral lipid levels were reduced in BSEP KO mice at baseline and under MCD conditions. Faecal non-esterified fatty acid concentrations at baseline and under MCD diet were markedly elevated in BSEP KO compared to WT mice. Serum liver enzymes and hepatic expression of inflammatory markers were increased in MCD-fed BSEP KO animals. PPAR alpha protein levels were reduced in BSEP KO mice. Accordingly, PPAR alpha downstream targets Fabp1 and Fatp5 were repressed, while NF kappa B subunits were increased in MCD-fed BSEP KO mice. Farnesoid X receptor (FXR) protein levels were reduced in MCD-fed BSEP KO vs WT mice. Hepatic BA profile revealed elevated levels of T beta MCA, exerting FXR antagonistic action, while concentrations of TCA (FXR agonistic function) were reduced. Conclusion Presence of hydroxylated BAs result in increased faecal FA excretion and reduced hepatic lipid accumulation. This aggravates development of MCD diet-induced hepatitis potentially by decreasing FXR and PPAR alpha signalling.
|
|
| 2. |
- Fuchs, C. D., et al.
(författare)
-
GLP-2 Improves Hepatic Inflammation and Fibrosis in Mdr2-/- Mice Via Activation of NR4a1/Nur77 in Hepatic Stellate Cells and Intestinal FXR Signaling
- 2023
-
Ingår i: Cellular and Molecular Gastroenterology and Hepatology. - 2352-345X. ; 16:5, s. 847-856
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND & AIMS: Glucagon-like peptide (GLP)-2 may exert antifibrotic effects on hepatic stellate cells (HSCs). Thus, we aimed to test whether application of the GLP-2 analogue teduglutide has hepatoprotective and antifibrotic effects in the Mdr2/Abcb4(-/-) mouse model of sclerosing cholangitis displaying hepatic inflammation and fibrosis. METHODS: Mdr2(-/-) mice were injected daily for 4 weeks with teduglutide followed by gene expression profiling (bulk liver; isolated HSCs) and immunohistochemistry. Activated HSCs (LX2 cells) and immortalized human hepatocytes and human intestinal organoids were treated with GLP-2. mRNA profiling by reverse transcription polymerase chain reaction and elec-trophoretic mobility shift assay using cytosolic and nuclear protein extracts was performed. RESULTS: Hepatic inflammation, fibrosis, and reactive chol-angiocyte phenotype were improved in GLP-2-treated Mdr2(-/-) mice. Primary HSCs isolated from Mdr2(-/-)mice and LX2 cells exposed to GLP-2 in vitro displayed significantly increased mRNA expression levels of NR4a1/Nur77 (P < .05). Electro-phoretic mobility shift assay revealed an increased nuclear NR4a1 binding after GLP-2 treatment in LX2 cells. Moreover, GLP-2 alleviated the Tgf beta-mediated reduction of NR4a1 nuclear binding activity. In vivo, GLP-2 treatment of Mdr2(-/-) mice resulted in increased intrahepatic levels of muricholic acids (accordingly Cyp2c70 mRNA expression was significantly increased), and in reduced mRNA levels of Cyp7a1 and FXR. Serum Fgf15 levels were increased in Mdr2(-/-) mice treated with GLP-2. Accordingly, GLP-2 treatment of human intestinal organoids activated their FXR-FGF19 signaling axis. CONCLUSIONS: GLP-2 treatment increased NR4a1/Nur77 activation in HSCs, subsequently attenuating their activation. GLP-2 promoted intestinal Fxr-Fgf15/19 signaling resulting in reduced Cyp7a1 and increased Cyp2c70 expression in the liver, contributing to hepatoprotective and antifibrotic effects of GLP2 in the Mdr2(-/-) mouse model.
|
|
| 3. |
- Fuchs, C. D., et al.
(författare)
-
Tetrahydroxylated bile acids improve cholestatic liver and bile duct injury in the Mdr2(-/-) mouse model of sclerosing cholangitis via immunomodulatory effects
- 2022
-
Ingår i: Hepatology communications.. - : Ovid Technologies (Wolters Kluwer Health). - 2471-254X. ; 6:9, s. 2368-2378
-
Tidskriftsartikel (refereegranskat)abstract
- Bile salt export pump (Bsep) (Abcb11)(-/-) mice are protected from acquired cholestatic injury due to metabolic preconditioning with a hydrophilic bile acid (BA) pool with formation of tetrahydroxylated bile acids (THBAs). We aimed to explore whether loss of Bsep and subsequent elevation of THBA levels may have immunomodulatory effects, thus improving liver injury in the multidrug resistance protein 2 (Mdr2) (Abcb4)(-/-) mouse. Cholestatic liver injury in Mdr2(-/-)Bsep(-/-) double knockout (DKO), Mdr2(-/-), Bsep(-/-), and wild-type mice was studied for comparison. Mdr2(-/-) mice were treated with a THBA (3 alpha,6 alpha,7 alpha,12 alpha-Tetrahydroxycholanoic acid). RNA/protein expression of inflammatory/fibrotic markers were investigated. Serum BA-profiling was assessed by ultra-performance liquid chromatography tandem mass spectrometry. Hepatic immune cell profile was quantified by flow cytometric analysis (FACS). In vitro, the THBA effect on chenodeoxycholic acid (CDCA)-induced inflammatory signaling in hepatocyte and cholangiocytes as well as lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma)-induced macrophage activation was analyzed. In contrast to Mdr2(-/-), DKO mice showed no features of sclerosing cholangitis. Sixty-seven percent of serum BAs in DKO mice were polyhydroxylated (mostly THBAs), whereas Mdr2(-/-) mice did not have these BAs. Compared with Mdr2(-/-), DKO animals were protected from hepatic inflammation/fibrosis. THBA feeding in Mdr2(-/-) mice improved liver injury. FACS analysis in DKO and Mdr2(-/-) THBA-fed mice showed changes of the hepatic immune cell profile towards an anti-inflammatory pattern. Early growth response 1 (EGR1) protein expression was reduced in DKO and in Mdr2(-/-) THBA-fed mice compared with Mdr2(-/-) control mice. In vitro, THBA-reduced CDCA induced EGR1 protein and mRNA expression of inflammatory markers in hepatocytes and cholangiocytes. LPS/IFN-gamma-induced macrophage activation was ameliorated by THBA. THBAs repress EGR1-related key pro-inflammatory pathways. Conclusion: THBA and their downstream targets may represent a potential treatment strategy for cholestatic liver diseases.
|
|
