Association of the S267F variant on NTCP gene and treatment response to pegylated interferon in patients with chronic hepatitis B: a multicentre study

Eliminating viral hepatitis in children after liver transplants: How to reach the goal by 2030

Viral hepatitis infections are a great burden in children who have received liver transplant. Hepatotropic viruses can cause liver inflammation that can develop into liver graft fibrosis and cirrhosis over the long term. Immunological reactions due to viral hepatitis infections are associated with or can mimic graft rejection, rendering the condition difficult to manage. Prevention strategies using vaccinations are agreeable to patients, safe, cost-effective and practical. Hence, strategies to eliminate viral hepatitis A and B focus mainly on immunization programmes for children who have received a liver transplant. Although a vaccine has been developed to prevent hepatitis C and E viruses, its use is not licensed worldwide. Consequently, eliminating hepatitis C and E viruses mainly involves early detection in children with suspected cases and effective treatment with antiviral therapy. Good hygiene and sanitation are also important to prevent hepatitis A and E infections. Donor blood products and liver grafts should be screened for hepatitis B, C and E in children who are undergoing liver transplantation. Future research on early detection of viral hepatitis infections should include molecular techniques for detecting hepatitis B and E. Moreover, novel antiviral drugs for eradicating viral hepatitis that are highly effective and safe are needed for children who have undergone liver transplantation.

Genetically edited hepatic cells expressing the NTCP-S267F variant are resistant to hepatitis B virus infection

The sodium-dependent taurocholate co-transporting polypeptide (NTCP)-S267F variant is known to be associated with a reduced risk of hepatitis B virus (HBV) infection and disease progression. The NTCP-S267F variant displays diminished function in mediating HBV entry, but its function in HBV infection has not been fully established in more biologically relevant models. We introduced the NTCP-S267F variant and tested infectivity by HBV in genetically edited hepatic cells. HepG2-NTCP clones with both homozygous and heterozygous variants were identified after CRISPR base editing. NTCP-S267F homozygous clones did not support HBV infection. The heterozygote clones behaved similarly to wild-type clones. We generated genetically edited human stem cells with the NTCP-S267F variant, which differentiated equally well as wild-type into hepatocyte-like cells (HLCs) expressing high levels of hepatocyte differentiation markers. We confirmed that HLCs with homozygous variant did not support HBV infection, and heterozygous variant clones were infected with HBV equally as well as the wild-type cells. In conclusion, we successfully introduced the S267F variant by CRISPR base editing into the NTCP/SLC10A gene of hepatocytes, and showed that the variant is a loss-of-function mutation. This technology of studying genetic variants and their pathogenesis in a natural context is potentially valuable for therapeutic intervention against HBV.

Bona fide receptor for hepatitis B and D viral infections: Mechanism, research models and molecular drug targets

Hepatitis B infections have become a serious public health issue globally, and the current first-line antiviral treatment for this disease is not a true cure. Recently, sodium taurocholate cotransporting polypeptide (NTCP), a liver-specific bile acid transporter, was identified as a bona fide receptor for hepatitis B virus (HBV) and its satellite virus, hepatitis delta virus (HDV). Identification of the HBV receptor has led to the development of robust cell cultures and provides a potential target for new treatments. This review summarizes the process by which NTCP was discovered and describes its clinical significance as the receptor for HBV and HDV entry.

Genetic variations of NTCP are associated with susceptibility to HBV infection and related hepatocellular carcinoma

Sodium taurocholate cotransporting polypeptide (NTCP), encoded by gene SLC10A1, is a receptor for hepatitis B virus (HBV). The aim of the current study was to investigate the role of NTCP polymorphisms in HBV susceptibility, cirrhosis and hepatocarcinogenesis. A total 1221 cases [including 866 chronic hepatitis B (CHB), 238 liver cirrhosis (LC), 117 hepatocellular carcinoma (HCC) patients] and 1232 healthy controls (HCs) were recruited, and 6 single nucleotide polymorphisms (SNPs) were genotyped. Meta-analysis was executed among 14591 CHBs and 12396 HCs to determine the association between NTCP polymorphisms and HBV infection, cirrhosis or hepatocarcinogenesis. The frequency of rs2296651-GA was inversely correlated with CHB, LC or HCC patients [adjusted OR(95%CI)=0.16(0.11-0.23), p<0.001; 0.34(0.21-0.55), p=0.001; or 0.46(0.25-0.83), p=0.008], respectively, compared with HCs. Meta-analysis also showed that NTCP rs2296651-GA was inversely associated with HBV infection [OR(95%CI)=0.532(0.287-0.986), p=0.028, codominant] or HBV-related HCC [OR(95%CI)=0.701(0.564-0.872), p=0.001, recessive]. Furthermore, the frequency of rs943277-GA was positively correlated with HBV infection [adjusted OR(95%CI)=2.42(1.05-5.54), p=0.032, codominant]. Our data suggest that NTCP mutants contribute to the susceptibility of HBV infection or HBV-related HCC.