Bcl2 is a critical regulator of bile acid homeostasis by dictating Shp and lncRNA H19 function

Abstract

Bile acid (BA) metabolism is tightly controlled by nuclear receptor signaling to coordinate regulation of BA synthetic enzymes and transporters. Here we reveal a molecular cascade consisting of the antiapoptotic protein BCL2, nuclear receptor Shp, and long non-coding RNA (lncRNA) H19 to maintain BA homeostasis. Bcl2 was overexpressed in liver of C57BL/6J mice using adenovirus mediated gene delivery for two weeks. Hepatic overexpression of Bcl2 caused drastic accumulation of serum BA and bilirubin levels and dysregulated BA synthetic enzymes and transporters. Bcl2 reactivation triggered severe liver injury, fibrosis and inflammation, which were accompanied by a significant induction of H19. Bcl2 induced rapid SHP protein degradation via the activation of caspase-8 pathway. The induction of H19 in Bcl2 overexpressed mice was contributed by a direct loss of Shp transcriptional repression. H19 knockdown or Shp re-expression largely rescued Bcl2-induced liver injury. Strikingly different than Shp, the expression of Bcl2 and H19 was hardly detectable in adult liver but was markedly increased in fibrotic/cirrhotic human and mouse liver. We demonstrated for the first time a detrimental effect of Bcl2 and H19 associated with cholestatic liver fibrosis and an indispensable role of Shp to maintain normal liver function.

A Novel Small Molecule Activator of Nuclear Receptor SHP Inhibits HCC Cell Migration via Suppressing Ccl2

“…SHP possesses the essential characteristics as a tumor suppressor gene, based on its ability to inhibit HCC cell proliferation (18), activate apoptosis (22, 23), repress DNA methylation (20, 21), suppress HCC cell migration and invasion (the present study), its downregulation in HCC (19), and its inhibition of oncogenic non-coding RNAs (39, 40). In particular, SHP expression is negatively correlated with patient survival in several types of aggressive and highly metastatic human cancers, including gastric cancer and breast cancer, suggesting it may be an attractive target for cancer therapy that is not limited to HCC.…”

Long non-coding RNA in liver metabolism and disease: Current status

“…41 Hepatic overexpression of H19RNA facilitated the development of obstructive cholestatic liver fibrosis. 42 Mechanistically, H19 downregulated hepatic zinc finger E-box-binding homeobox 1 (ZEB1), and impeded its suppression of epithelial cell adhesion molecule (EpCAM), which in turn augmented bile duct ligation (BDL)-induced liver fibrosis.…”

Loss of miR-141/200c ameliorates hepatic steatosis and inflammation by reprogramming multiple signaling pathways in NASH

“…The coded human liver specimens were obtained through the Liver Tissue Cell Distribution System funded by NIH Contract HSN276201200017C, as described previously (35)(36)(37). Three groups of liver specimens were used: control normal (n = 10), NASH nonfatty liver (n = 15), and NASH fatty liver (n = 20).…”

“…Approximately 4-μm thick sections were deparaffinized and then stained with H&E and Masson's trichrome (43). Livers embedded in Tissue-Tek OCT compound were cut at 10 μm for F4/80 IHC and Oil Red O staining (35). Liver sections were incubated with rat anti-mouse F4/80 (MCA497GA, Bio-Rad) overnight and incubated with HRP-conjugated goat anti-rat IgG secondary antibody (Bio-Rad) for 1 hour before detection with DAB substrate (Vector Laboratories).…”

“…The human hepatocellular carcinoma cell lines HepG2 and Huh7 (Health Science Research Resources Bank, JCRB0403) (38) were cultured in DMEM containing glucose (4.5 g/l) and 10% FBS (Gibco, Thermo Fisher Scientific) under standard conditions as described previously (35,39). Primary mouse hepatocytes were isolated from 10-week-old WT and miR-141/200c -/-mice as previously described (39,40).…”