Clinical features of sodium taurocholate cotransporting polypeptide deficiency and an analysis of SLC10A1 gene mutation / 临床肝胆病杂志

Objective To investigate the clinical and gene mutation features of sodium taurocholate cotransporting polypeptide (NTCP) deficiency. Methods A total of 10 children, aged 50%). Second-generation gene sequencing showed that all 10 children had a homozygous mutation of the SLC10A1 gene, i.e., c.800C > T(p.Ser267Phe, chr14∶70245193). Conclusion Although NTCP deficiency often has no symptoms, some of the children may manifest as infant cholestasis in the early stage. The possibility of NTCP deficiency should be considered when there is persistent hypercholanemia and the changing trend of serum TBA is not consistent with that of other liver function parameters.

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.

Research advances in the pathogenesis, clinical manifestations, and diagnosis/treatment of sodium-taurocholate cotransporting polypeptide deficiency / 临床肝胆病杂志

Sodium-taurocholate cotransporting polypeptide (NTCP) deficiency is a new hereditary bile acid metabolic disease due to biallelic mutations of the SLC10A1 gene and is not rare in China. Marked and persistent hypercholanemia in childhood is the major clinical feature of NTCP deficiency, and this condition might be involved in the development of neonatal hyperbilirubinemia, cholestasis in early infancy, and cholestasis in pregnancy. At present, there lack specific therapies for NTCP deficiency, but such patients tend to have good prognosis. SLC10A1 gene detection may facilitate the timely and definite diagnosis of this disease and thus avoid unnecessary examinations and interventions.

Construction of NTCP-Huh7 cell lines and their susceptibility to HBV / 医学研究生学报

ObjectiveThe transient expression of the functional receptor sodium taurocholate cotransporting polypeptide (NTCP) leads to the inefficiency and instability of the hepatitis B virus (HBV)-associated hepatocellular carcinoma cell model. The aim of this study was to construct NTCP-Huh7 cell lines by transfecting GV358-NTCP into Huh7 cells and identify their susceptibility to HBV.MethodsThe recombinant plasmid GV358-NTCP was obtained by ligation of GV358 and NTCP, and then transfected into Huh7 cells for the construction of NTCP-Huh7 cells. The NTCP-Huh7 cells (NTCP-Huh7 group) and Huh7 cells (Huh7 group) were infected with HBV and co-incubated with HBV for 18 hours, and the co-incubation was continued after change of the culture medium. At 2, 4, 6, 8, 10, and 12 days of incubation, the supernatant and cells were collected for measurement of the contents of HBsAg, HBeAg, HBcAg and HBV DNA in the supernatant and HBV cccDNA in the cells as well as for determination of HBV susceptibility of the NTCP-Huh7 recombinant cells.ResultsWestern blot showed stably expressed NTCP proteins in the NTCP-Huh7 cells. At 8 days of incubation, the levels of HBsAg and HBeAg were significantly higher in the NTCP-Huh7 group (0.866±0.040 and 0.603±0.053) than in the Huh7 group (0.237±0.063 and 0.209±0.112) (P<0.05), reaching the peak at 8 days and also remarkably higher in the former than in the latter group at 4, 6 and 10 days (P < 0.05). So were the levels of HBV DNA and HBV cccDNA in the NTCP-Huh7 than in the Huh7 group at 4, 6, 8, 10 and 12 days (P < 0.05). Immunofluorescence assay revealed the core antigen of HBV in the NTCP-Huh7 but not in Huh7 cells.ConclusionNTCP-Huh7 cells obtained by transfection of the GV358-NTCP recombinant plasmid into Huh7 cells are susceptible to HBV infection.

Recent advances in the diagnosis and treatment of pediatric genetic cholestasis / 中华实用儿科临床杂志

Cholestasis is defined as a conjugated bilirubin level >1 mg/dL(17.1 μmol/L)if total serum bilirubin is ≤5 mg/dL(85.5 μmol/L),or conjugated bilirubin fraction >20％of total bilirubin when the total bilirubin is >5 mg/dL(85.5 μmol/L).In the recent years,the diagnosis and management of genetic cholestasis have caused considerable attention in the pediatric world,in pace with the development,maturation,and clinical application of the theories and techniques in genomics as well as molecular genetics.With a diversity of causative genes,genetic cholestasis usually demonstrates nonpathognomonic clinical manifestations.The etiology diagnosis such a disease relies on genetic tests,the treatment is often difficult,and the prognosis varies disparately,usually causing tremendous pain and burden on the affected patient and the family as well.Taking citrin deficiency,mitochondrial DNA depletion syndrome,microvi-llus inclusion disease and sodium taurocholate cotransporting polypeptide deficiency as samples,the recent advances in the diagnosis and treatment of genetic cholestasis are addressed.

Polymorphisms in p.S267F of SLC10A1 gene is associated with clinical outcomes of HBV infection / 中华临床感染病杂志

Objective To investigate the association of restriction fragment length polymorphisms (RFLP) in p.S267F of SLC10A1 gene with clinical outcomes of hepatitis B virus (HBV) infection. Methods Clinical data of 1 268 patients with HBV infections admitted in Public Health Clinical Center Affiliated to Fudan University during July 2014 and February 2015 were collected.Polymerase chain reaction-restriction fragment length polymorphism ( PCR-RFLP) method was used to genotype the p .S267F of SLC10A1 gene in all patients, and the potential association between variants in p .S267F of SLC10A1 gene and the clinical outcomes of HBV infection was analyzed .Results Among 1 268 patients with HBV infections, 1 226 were of genotype CC, and 42 were of genotype CT, so the variation rate in p.S267F was 3.31%(42/1 268).Compared with patients with genotype CC , patients with genotype CT had a higher incidence of acute HBV infections (13.6%vs.28.6%,χ2 =19.819, P<0.05) and a lower incidence of HBV-related liver cirrhosis or hepatocellular carcinoma (13.9% vs.4.8%, χ2 =18.945, P <0.05). Conclusion RFLP in p.S267F of SLC10A1 gene may be associated with chronicity and aggravation of HBV infection, and genotype CT is possibly a protective factor .

Receptor for Hepatitis B and D Virus / 대한내과학회지

Chronic hepatitis B affects 400 million people worldwide and is one of the leading causes of liver-related morbidity and mortality. All clinically available hepatitis B virus (HBV) drugs are nucleoside or nucleotide analogs that inhibit viral reverse transcriptase (RT) activity. Resistance to these HBV drugs has been widely reported, and is due to specific mutations in the viral RT domain. Therefore, the development of new, non-polymerase targeting anti-HBV agents is urgently needed. A potential drug target, the HBV receptor that mediates the viral entry process, has been recently identified using human primary hepatocytes, northern tree shrew (Tupaia belangeri) hepatocytes, and HepaRG cells. A transporter of bile acids, sodium taurocholate cotransporting polypeptide (NTCP), was identified as the receptor for HBV and hepatitis D virus, and the transport function of NTCP was correlated with HBV entry. Therefore, functional inhibitors of NTCP may inhibit HBV infection, and viral entry was blocked by several NTCP receptor-targeting compounds. The HBV receptor is an attractive target for development of entry inhibitors, and serves as a model for the mechanistic study of HBV entry and infection. This review will summarize the characteristics and clinical importance of NTCP, and will discuss the potential therapeutic use of NTCP inhibitors to prevent HBV entry.

From DCPD to NTCP: The long journey towards identifying a functional hepatitis B virus receptor

Hepatitis B virus (HBV) is the prototype of hepatotropic DNA viruses (hepadnaviruses) infecting a wide range of human and non-human hosts. Previous studies with duck hepatitis B virus (DHBV) identified duck carboxypeptidase D (dCPD) as a host specific binding partner for full-length large envelope protein, and p120 as a binding partner for several truncated versions of the large envelope protein. p120 is the P protein of duck glycine decarboxylase (dGLDC) with restricted expression in DHBV infectible tissues. Several lines of evidence suggest the importance of dCPD, and especially p120, in productive DHBV infection, although neither dCPD nor p120 cDNA could confer susceptibility to DHBV infection in any cell line. Recently, sodium taurocholate cotransporting polypeptide (NTCP) has been identified as a binding partner for the N-terminus of HBV large envelope protein. Importantly, knock down and reconstitution experiments unequivocally demonstrated that NTCP is both necessary and sufficient for in vitro infection by HBV and hepatitis delta virus (HDV), an RNA virus using HBV envelope proteins for its transmission. What remains unclear is whether NTCP is the major HBV receptor in vivo. The fact that some HBV patients are homozygous with an NTCP mutation known to abolish its receptor function suggests the existence of NTCP-independent pathways of HBV entry. Also, NTCP very likely mediates just one step of the HBV entry process, with additional co-factors for productive HBV infection still to be discovered. NTCP offers a novel therapeutic target for the control of chronic HBV infection.

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.