Lipid nanoparticle-mediated delivery of IL-21-encoding mRNA induces viral clearance in mouse models of hepatitis B virus persistence.

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), the transcription template for all viral mRNAs, is highly stable and current treatment options cannot effectively induce its clearance. Previously, we established an HBV persistence mouse model based on a clinical isolate (termed BPS) and identified interleukin-21 (IL-21) as a potent inducer of HBV clearance. Lipid nanoparticle (LNP) mediated delivery of mRNA has proven to be a highly safe and effective delivery platform. This work explored the applicability and effectiveness of the mRNA-LNP platform in IL-21-based HBV therapies. First, LNP-encapsulated murine IL-21 mRNA (LNP-IL-21) was prepared, characterized, and demonstrated to engender IL-21 expression in vitro and in vivo. Next, LNP-IL-21 was shown to induce clearance of both serum and intrahepatic HBV antigen and DNA in two HBV persistence mouse models based on BPS and recombinant cccDNA (rcccDNA), respectively, which was associated with HBV-specific humoral and cellular immune responses. Furthermore, peripheral blood mononuclear cells from BPS persistence mice treated ex vivo with LNP-IL-21 and HBV surface antigen (HBsAg) could induce similar HBV clearance upon infusion into recipient mice. These findings indicated that IL-21 combined with mRNA-LNP platform represents a valid and promising strategy for developing novel therapeutics against chronic HBV infection.

Naturally occurring 5' preS1 deletions markedly enhance replication and infectivity of HBV genotype B and genotype C.

BACKGROUND AND AIMS: Deletion of 15-nucleotide or 18-nucleotide (nt) covering preS1 ATG frequently arises during chronic infection with HBV genotypes B and C. Since the second ATG is 33nt downstream, they truncate large (L) envelope protein by 11 residues like wild-type genotype D. This study characterised their functional consequences. METHODS: HBV genomes with or without deletion were amplified from a patient with advanced liver fibrosis and assembled into replication competent 1.1mer construct. Deletion, insertion or point mutation was introduced to additional clones of different genotypes. Viral particles concentrated from transfected HepG2 cells were inoculated to sodium taurocholate cotransporting polypeptide (NTCP)-reconstituted HepG2 (HepG2/NTCP) cells or differentiated HepaRG cells, and HBV RNA, DNA, proteins were monitored. RESULTS: From transfected HepG2 cells, the 15-nt and 18-nt deletions increased HBV RNA, replicative DNA and extracellular virions. When same number of viral particles was inoculated to HepG2/NTCP cells, the deletion mutants showed higher infectivity. Conversely, HBV infectivity was diminished by putting back the 18nt into naturally occurring genotype C deletion mutants and by adding 33nt to genotype D. Infectivity of full-length genotype C clones was also enhanced by mutating the first ATG codon of the preS1 region but diminished by mutating the second in-frame ATG. Removing N-terminal 11 residues from preS1 peptide 2-59 of genotype C potentiated inhibition of HBV infection and enhanced binding to HepG2/NTCP cells. CONCLUSIONS: The 15-nt and 18-nt deletions somehow increase HBV RNA, replicative DNA and virion production. Shortened L protein is more efficient at mediating HBV infection.

Platelet activation during chronic hepatitis B infection exacerbates liver inflammation and promotes fibrosis.

Recurrent hepatitis activity during chronic hepatitis B virus infection results in fibrosis and even hepatocellular carcinoma. It is still unclear what causes acute exacerbation. As platelets have recently been identified as a significant role in inflammation, we here investigated the role of platelets in mediating liver damage in patients with chronic hepatitis B virus infection. Platelet aggregation testing and flow cytometry were carried out to evaluate platelet activation status in 121 patients chronically infected with hepatitis B across different phases of the condition. The correlation between platelet aggregation rate and liver inflammation or liver fibrosis index was evaluated. To investigate the genesis of platelet activation, several serum cytokines were also assessed by MILLIPLEX microsphere-based multiplex cytokine assay. Active hepatitis patients showed a higher aggregation rate than others. Levels of CD62p, a marker of platelet activation, were also increased in this group of patients. Positive correlations between platelet aggregation rate and liver inflammation or liver fibrosis were also noted, indicating a significant role of platelet in the progression of liver disease. The level of tumor necrosis factor-alpha, which is known to trigger platelet activation, was markedly higher in the active hepatitis group (P < .005). Based on the findings in our study, platelet activation plays a vital role in the progression of chronic hepatitis B virus infection. Antiplatelet therapy may provide a new means of hepatitis B infection treatment.

Development and Validation of a Novel Model to Predict Liver Histopathology in Patients with Chronic Hepatitis B.

It is still vague for chronic hepatitis B (CHB) patients with normal or mildly increasing alanine aminotransferase (ALT) level to undergo antiviral treatment or not. The purpose of our study was to establish a noninvasive model based on routine blood test to predict liver histopathology for antiviral therapy. This retrospective study enrolled 258 CHB patients with liver biopsy from the First Hospital of Quanzhou (training cohort, n=126) and Huashan Hospital (validation cohort, n=132). Histologic grading of necroinflammation (G) and liver fibrosis (S) was performed according to the Scheuer scoring system. A novel model, ATPI, including aspartate aminotransferase (AST), total bilirubin (TBil), and platelets (PLT), was developed in training cohort. The area under ROC curves (AUC) of ATPI for predicting antiviral therapy indication was 0.83 in training cohort and was 0.88 in the validation cohort, respectively. Similarly, ATPI also displayed the highest AUC in predicting antiviral therapy indication in CHB patients with normal or mildly increasing ALT level. In conclusion, ATPI is a novel independent model to predict liver histopathology for antiviral therapy in CHB patients with normal and mildly increased ALT levels.

A promising non-invasive index for predicting liver inflammation in chronic hepatitis B patients with alanine aminotransferase ≤2 upper limit of normal.

Inexpensive and simple non-invasive indexes for predicting liver inflammation are urgently required, but have been poorly studied in chronic hepatitis B (CHB) patients with alanine transaminase (ALT) ≤2 times the upper limit of normal (ULN). A total of 356 CHB patients with ALT ≤2 ULN who presented at Huashan Hospital (n=181) and the First Hospital of Quanzhou (n=175) were enrolled and randomly divided into an experimental assessment cohort (n=238) and validation cohort (n=118) at a ratio of 2:1. Histological analysis of liver tissue was performed to determine the pathological stage according to the Scheuer scoring system. For the experimental assessment cohort, univariate and multivariate analysis identified aspartate aminotransferase (AST) and albumin (ALB) as independent predictors of liver necroinflammation [liver necroinflammation grade (G)≥2] in patients with ALT ≤2 ULN. Therefore, a novel index, the AST-to-ALB ratio (ATAR), was proposed, which had a better diagnostic performance [area under receiver operating characteristic curve (AUC)=0.721] than that of ALB (AUC=0.632; P=0.039 vs. ATAR) and AST (AUC=0.682; P=0.082 vs. ATAR). In the validation cohort, the AUC of ATAR (0.728) to identify patients with a G≥2 was slightly greater than that of AST (0.660; P=0.149 vs. ATAR) and ALB (0.672; P=0.282 vs. ATAR). Furthermore, a similar diagnostic superiority was also demonstrated in patients with ALT ≤1 ULN. Thus, ATAR may be a promising non-invasive surrogate marker for liver necroinflammation CHB patients with ALT ≤2 ULN and thereby determine whether anti-viral treatment should be initiated.