Bile acid coordinates microbiota homeostasis and systemic immunometabolism in cardiometabolic diseases

Cardiometabolic disease (CMD), characterized with metabolic disorder triggered cardiovascular events, is a leading cause of death and disability. Metabolic disorders trigger chronic low-grade inflammation, and actually, a new concept of metaflammation has been proposed to define the state of metabolism connected with immunological adaptations. Amongst the continuously increased list of systemic metabolites in regulation of immune system, bile acids (BAs) represent a distinct class of metabolites implicated in the whole process of CMD development because of its multifaceted roles in shaping systemic immunometabolism. BAs can directly modulate the immune system by either boosting or inhibiting inflammatory responses via diverse mechanisms. Moreover, BAs are key determinants in maintaining the dynamic communication between the host and microbiota. Importantly, BAs via targeting Farnesoid X receptor (FXR) and diverse other nuclear receptors play key roles in regulating metabolic homeostasis of lipids, glucose, and amino acids. Moreover, BAs axis per se is susceptible to inflammatory and metabolic intervention, and thereby BAs axis may constitute a reciprocal regulatory loop in metaflammation. We thus propose that BAs axis represents a core coordinator in integrating systemic immunometabolism implicated in the process of CMD. We provide an updated summary and an intensive discussion about how BAs shape both the innate and adaptive immune system, and how BAs axis function as a core coordinator in integrating metabolic disorder to chronic inflammation in conditions of CMD.

Recent advances in drug development targeting bile acids transporters and related disease / 药学学报

Bile acids (BAs) are a major component of bile salt, which plays a vital role in the metabolism of lipids in humans. Ninety-five percent of bile acids are recycled by the enterohepatic circulation (EHC), and therefore EHC is essential for bile acid homeostasis. There are four transporters that mediate the transmembrane transport of bile acids, each of which plays an important role in the enterohepatic circulation. Gene defects in bile acid transporters can lead to disorders of the enterohepatic circulation, ultimately leading to clinical phenotypes such as metabolic diseases and even death. Bile transporter expression is altered in patients with various metabolic disease states, suggesting that disruption of bile acid transporters may be a pivotal pathological mechanism for the development of metabolism diseases. Thus, many drugs targeting bile acid transporters are being developed. We provide a concise overview of the progress of bile acid transporters research, discuss the relationship between different bile acid transporters and disease development, and summarize the current progress in drug development targeting bile acid transporters.

CRISPR-Cas9: A method for establishing rat models of drug metabolism and pharmacokinetics

The 2020 Nobel Prize in Chemistry recognized CRISPR-Cas9, a super-selective and precise gene editing tool. CRISPR-Cas9 has an obvious advantage in editing multiple genes in the same cell, and presents great potential in disease treatment and animal model construction. In recent years, CRISPR-Cas9 has been used to establish a series of rat models of drug metabolism and pharmacokinetics (DMPK), such as

Combined obeticholic acid and apoptosis inhibitor treatment alleviates liver fibrosis

Obeticholic acid (OCA), the first FXR-targeting drug, has been claimed effective in the therapy of liver fibrosis. However, recent clinical trials indicated that OCA might not be effective against liver fibrosis, possibly due to the lower dosage to reduce the incidence of the side-effect of pruritus. Here we propose a combinatory therapeutic strategy of OCA and apoptosis inhibitor for combating against liver fibrosis. CCl-injured mice, d-galactosamine/LPS (GalN/LPS)-treated mice and cycloheximide/TNF (CHX/TNF)-treated HepG2 cells were employed to assess the effects of OCA, or together with IDN-6556, an apoptosis inhibitor. OCA treatment significantly inhibited hepatic stellate cell (HSC) activation/proliferation and prevented fibrosis. Elevated bile acid (BA) levels and hepatocyte apoptosis triggered the activation and proliferation of HSCs. OCA treatment reduced BA levels but could not inhibit hepatocellular apoptosis. An enhanced anti-fibrotic effect was observed when OCA was co-administrated with IDN-6556. Our study demonstrated that OCA inhibits HSCs activation/proliferation partially by regulating BA homeostasis and thereby inhibiting activation of HSCs. The findings in this study suggest that combined use of apoptosis inhibitor and OCA at lower dosage represents a novel therapeutic strategy for liver fibrosis.

Progressive Familial Intrahepatic Cholestasis in Korea: A Clinicopathological Study of Five Patients

BACKGROUND: Progressive familial intrahepatic cholestasis (PFIC) is a heterogeneous group of autosomal recessive liver diseases that present as neonatal cholestasis. Little is known of this disease in Korea. METHODS: The records of five patients histologically diagnosed with PFIC, one with PFIC1 and four with PFIC2, by liver biopsy or transplant were reviewed, and ATP8B1 and ABCB11 mutation status was analyzed by direct DNA sequencing. Clinicopathological characteristics were correlated with genetic mutations. RESULTS: The first symptom in all patients was jaundice. Histologically, lobular cholestasis with bile plugs was the main finding in all patients, whereas diffuse or periportal cholestasis was identified only in patients with PFIC2. Giant cells and ballooning of hepatocytes were observed in three and three patients with PFIC2, respectively, but not in the patient with PFIC1. Immunostaining showed total loss of bile salt export pump in two patients with PFIC2 and focal loss in two. Lobular and portal based fibrosis were more advanced in PFIC2 than in PFIC1. ATP8B1 and ABCB11 mutations were identified in one PFIC1 and two PFIC2 patients, respectively. One PFIC1 and three PFIC2 patients underwent liver transplantation (LT). At age 7 months, one PFIC2 patient was diagnosed with concurrent hepatocellular carcinoma and infantile hemangioma in an explanted liver. The patient with PFIC1 developed steatohepatitis after LT. One patient showed recurrence of PFIC2 after 10 years and underwent LT. CONCLUSIONS: PFIC is not rare in patients with neonatal cholestasis of unknown origin. Proper clinicopathologic correlation and genetic testing can enable early detection and management.

Benign Recurrent Intrahepatic Cholestasis Type 2 in Siblings with Novel ABCB11 Mutations / 대한소아소화기영양학회지

Benign recurrent intrahepatic cholestasis (BRIC), a rare cause of cholestasis, is characterized by recurrent episodes of cholestasis without permanent liver damage. BRIC type 2 (BRIC2) is an autosomal recessive disorder caused by ABCB11 mutations. A 6-year-old girl had recurrent episodes of jaundice. At two months of age, jaundice and hepatosplenomegaly developed. Liver function tests showed cholestatic hepatitis. A liver biopsy revealed diffuse giant cell transformation, bile duct paucity, intracytoplasmic cholestasis, and periportal fibrosis. An ABCB11 gene study revealed novel compound heterozygous mutations, including c.2075+3A>G in IVS17 and p.R1221K. Liver function test results were normal at 12 months of age. At six years of age, steatorrhea, jaundice, and pruritus developed. Liver function tests improved following administration of phenylbutyrate and rifampicin. Her younger brother developed jaundice at two months of age and his genetic tests revealed the same mutations as his sister. This is the first report of BRIC2 confirmed by ABCB11 mutations in Korean siblings.

Therapeutic effects of emodin on acute choiestatic hepatitis and mechanism in rats / 中华实用儿科临床杂志

Objective To investigate the therapeutic effects of emodin on acute cholestatic hepatitis and mec-hanism thereof. Methods Fifty Sprague - Dawley (SD)rats were randomly divided into 5 groups and were treated with emodin,ursodeoxycholic acid,dexamethasone,or normal saline respectively for 4 days. On the fifth day gastric perfusion of alpha - naphthylisothiocyanate(ANIT)was performed to establish models of choiestatic hepatitis. Four to six hours after the establishment of model the above mentioned agents were given continuously. Forty - eight hours after the model establishment blood samples were collected from abdominal aorta to examine the total bilirubin(TB),direct bilirubin (DB),alanine aminotransferase(ALT),total bile acid(TBA),aspartate aminotransferase(AST),alkaline phosphatase (ALP),gamma glutamine transferase(GGT). Specimen of liver was collected to undergo pathological examination. Real - time PCR was used to detect the mRNA expression of farnesoid X receptor(FXR),small heterodimer partner (SHP ),bile salt export pump (BSEP ),uridine diphosphate glucuronosyltransferase 2 family polypeptide B4 (UGT2B4). Results The serum levels of total bilirubin (TB),direct bilirubin (DB),alanine aminotransferase (ALT),total bile acids (TBA),aspartate aminotransferase (AST),and alkaline phosphatase (ALP)of the model group were respectively (68. 1 ± 26. 1)μmol/ L,(46. 3 ± 20. 1)μmol/ L,(483 ± 228)U/ L,(159. 1 ± 57. 9)μmol/L,(2. 0 ± 0. 5)U/ L,(996 ± 382)U/ L,(324 ± 120)U/ L. The levels of TB,DB,ALT,TBA,AST,ALP of the emodin group were respectively (15. 0 ± 8. 7)μmol/ L,(10. 8 ± 3. 9)μmol/ L,(147 ± 71)U/ L,(60. 1 ± 22. 7)μmol/ L, (295 ± 104)U/ L,(222 ± 59)U/ L,and were all significantly lower than those of the model group (all P < 0. 05). The levels of TB,DB,ALT,TBA,AST,GGT,ALP of the emodin group were all significantly lower than those of the ursode-oxycholic acid group (all P < 0. 05). The levels of TB,DB,ALT,TBA,GGT,AST were all significantly lower than those of the dexamethasone group (all P < 0. 01). The expression levels of FXR,SHP,BSEP,UGT2B4 mRNA in the emodin group (1. 087 ± 0. 285,0. 892 ± 0. 390,0. 902 ± 0. 149,1. 785 ± 0. 403)were all significantly higher than those of the model group (0. 152 ±0. 088,0. 559 ±0. 194,0. 561 ±0. 123,0. 177 ±0. 039,all P <0. 05). Conclusions By decreasing the levels of TB,DB,ALT,TBA,AST,ALP and reducing pathological changes,emodin has a protective effect on cholestatic hepatitis. It has better effects than ursodeoxycholic acid and dexamethasone. These effects may be due to promoting FXR,SHP,BSEP and UGT2B4 expression.

Relationship between phenotype and genotype of ABCB11 deficiency in siblings and literature review / 中华儿科杂志

Objective@#To explore the relationship between genotype and phenotype of ABCB11 deficiency.@*Methods@#Clinical data of two siblings with ABCB11 deficiency were retrospectively analyzed. Related literature from PubMed, CNKI and Wangfang databases was reviewed to date (up to August 2017) with 'ABCB11 gene’ or 'bile salt export pump’, 'cholestasis’ and 'child’ as key words.@*Results@#The patients were siblings. Both of them presented as jaundice, pruritus and hepatosplenomegaly since 3 days after birth. Significant laboratory findings on admission of the older sister included high total bilirubin, 170 µmol/L;conjugated bilirubin, 115.8 µmol/L;alanine aminotransferase, 168 U/L;total bile acid 186.3 µmol/L and normal gamma-glutamyl transpeptidase. While routine laboratory data of the younger brother were as follows: total bilirubin, 148.8 µmol/L;conjugated bilirubin, 96.3 µmol/L;alanine aminotransferase, 232.8 U/L;total bile acid 226 µmol/L, and normal gamma-glutamyl transpeptidase.Both received ursodeoxycholic acid and fat-soluble vitamins. Liver pathology of the younger brother showed giant hepatocytes with ballooning degeneration, focal necrosis and intrahepatic cholestasis. Both the patients harbor the same compound heterozygous mutations in ABCB11 gene, c.145C>T (p.Q49X) and c.1510G>A (p.E504K). The sister is 9 years old now, with normal liver function. Jaundice faded around 3 months after birth, pruritus relieved at age 5, and medications was stopped since then. The brother progressed to liver failure after an operation on perianal abscess when he was 8-month-old, and received living-related liver transplantation when he was 9 month and 20 days old (from his mother). Now he is 1 year and 5 months old, with normal liver function. Both are under our follow-up. Literature review revealed 18 ABCB11 deficiency patients from 7 families who had apparent different prognoses, within each family the siblings had the same ABCB11 gene mutation. Seven cases relieved after ursodeoxycholic acid therapy and/or partial external biliary diversion, 5 received orthotopic liver transplantation, 2 developed hepatocellular carcinoma and 4 cases died in childhood.@*Conclusions@#The clinical manifestations of ABCB11 deficiency may vary greatly in patients carrying the same genotype, even in siblings. Patients should be managed in individualized maner.

Metabolic effects of intestinal absorption and enterohepatic cycling of bile acids

The classical functions of bile acids include acting as detergents to facilitate the digestion and absorption of nutrients in the gut. In addition, bile acids also act as signaling molecules to regulate glucose homeostasis, lipid metabolism and energy expenditure. The signaling potential of bile acids in compartments such as the systemic circulation is regulated in part by an efficient enterohepatic circulation that functions to conserve and channel the pool of bile acids within the intestinal and hepatobiliary compartments. Changes in hepatobiliary and intestinal bile acid transport can alter the composition, size, and distribution of the bile acid pool. These alterations in turn can have significant effects on bile acid signaling and their downstream metabolic targets. This review discusses recent advances in our understanding of the inter-relationship between the enterohepatic cycling of bile acids and the metabolic consequences of signaling via bile acid-activated receptors, such as farnesoid X nuclear receptor (FXR) and the G-protein-coupled bile acid receptor (TGR5).

Effects of leptin on BSEP protein expression and signaling pathway in HepG2 cells / 中国病理生理杂志

AIM:To investigate the effects of leptin on the expression of bile salt export pump ( BSEP) and signaling pathway in human hepatocellular carcinoma cell line HepG2.METHODS: HepG2 cells were cultured in vitro. Leptin at concentrations of 10 -8 , 10 -7 and 10 -6 mol/L was used as a stimulating factor.The protein levels of adenosine monophosphate-activated protein kinase alpha subunit (AMPKa), phosphorylated AMPKa (p-AMPKa) and BSEP in the HepG2 cells at 24 h, 48 h and 72 h were detected by Western blotting.The optimal culture time and leptin concentration were selected, and compound C at concentration of 10 μmol/L was added to this group.The protein expression of BSEP was detected by Western blotting.RESULTS:Intervention of HepG2 cells with leptin for 72 h increased the protein ex-pression of AMPKa gradually in a concentration-dependent manner, and leptin at concentration of 10 -6 mol/L induced the strongest AMPKa expression ( P<0.01 ) .Intervention of HepG2 cells with leptin for 24 h increased the phosphorylation level of AMPKa gradually in a dose-dependent manner (P<0.01).The effect of leptin on the increase in the protein ex-pression of p-AMPKa was also in a time-dependent manner ( P<0.01) .After intervention with different concentrations of leptin for 24 h, the protein expression of BSEP in the HepG2 cells was gradually increased by the stimulation of leptin in a concentration-and time-dependent manner (P<0.01).Compared with NC group, the protein expression of BSEP in 10 -6 mol/L leptin group and 10 -6 mol/L leptin+10μmol/L compound C group was increased at 72 h (P<0.01), and that in 10-6 mol/L leptin+10 μmol/L compound C group was lower than that in 10 -6 mol/L leptin group at 72 h ( P<0.01 ) . CONCLUSION:Leptin promotes the protein expression of BSEP in HepG2 cells by leptin-AMPK-BSEP signaling path-way.Leptin promotes the increases in AMPKa protein and the level of phosphorylation of AMPKa in HepG2 cells.

Regulation effect of isoniazid on the expression of hepatobiliary membrane transporters Mrp2, Bsep, P-gp and Ntcp in mouse / 中国药学杂志

OBJECTIVE: To investigate the regulation effect of isoniazid on the hepatobiliary membrane transporters multidrug resistance protein 2 (Mrp2), bile salt export pump (Bsep), P-glycoproteins (P-gp), sodium taurocholate cotransporting plypeptide (Ntcp), and which would lay the foundation for the studies of the mechanism on isoniazid-induced liver injury from the level of transporters. METHODS: Following an oral dose of 30, 60, 120 mg · kg-1 · d-1 for 1, 2 and 3 months in mouse respectively, the biochemical indicator of serum were determined; the liver were removed for hepatic pathology; the protein mass of Bsep, Mrp2, Ntcp and P-gp were analyzed by Western Blotting. RESULTS: After high/middle/low dose isoniazid administration, the expression of Mrp2, Bsep, P-gp and Ntcp were all changed, especially the high/middle dose group. In addition, the biochemical and pathological were significantly lagged behind the expression change of the transporters. CONCLUSION: The hepatotoxicity of isoniazid may be associated with excessive hepatic accumulation of the related exogenous substances that medicated by Mrp2, Bsep, P-gp and Ntcp.

Genetic diagnosis of progressive familial intrahepatic cholestasis type 2 / 临床儿科杂志

Objectives To investigate the clinical features of progressive familial intrahepatic cholestasis type 2 (PFIC2) and to illustrate the importance of genetic diagnosis. Methods The mutations in 27 exons of ABCB11 encoding bile salt export pump (BSEP) were identiifed using polymerase chain reaction (PCR) and direct DNA sequencing in 6 children with suspected PFIC2. The pathogenicity of the newly identiifed mutations were predicted by SIFT, PolyPhen-2, SNPs&GO software. The clini-cal features and laboratory examinations were reviewed. Results Four disease-causing mutations, p.R928*, p.E554K, p.R575Q and p.Y337H were identiifed, and the last three mutations were novel. These three kinds of novel mutations can cause the disease. Two children with genetic diagnosis had such manifestations as onset within a month after birth, jaundice, hepatosplenomegaly, upset, increased levels of total bilirubin and direct bilirubin, GGT<100 U/L and high levels of total bile acid. Conclusions Genetic diagnosis is a potent tool for clinical diagnosis of PFIC2.

Role of AMPK in regulation of bile acid metabolism / 国际外科学杂志

Adenosine monophosphate-activated protein kinase (AMPK) activation also can inhibit the synthesis of cholesterol and fat.Recent studies have shown that activation of AMPK can also inhibit the synthesis of bile acid and promote bile salt export pump' s generation.All of those illustrated that AMPK played an important role in regulating bile acid metabolism.This article will summarize the AMPK activation pathway,bile acid metabolism,AMPK activity in bile acid synthesis and transfer,and so on.

ABCB11 Gene Variation and Cholestatic Diseases / 实用儿科临床杂志

ABCB11 gene encodes bile salt export pump (BSEP).It is almost exclusively expressed in the canalicular microvilli of liver.It is the principal conveyor of bile acids from hepatocyte cytoplasm into bile canaliculus.It is clearly that BSEP defects can induce progressive familial intrahepatic cholestasis type 2 and benign recurrent intrahepatic cholestasis type 2.ABCB11 gene variation are also responsible for intrahepatic cholestasis of pregnancy,drug-induced cholestasis,primary sclerosis cholangitis and primary bile cirrhosis.This paper reviewed the association of ABCB11 gene variation and these diseases.