JHEP Reports最新文献

Background & Aims

Circulating HBV RNAs have been proposed as a biomarker that reflects the transcriptional activity of covalently closed circular DNA (cccDNA) and may help to evaluate HBV treatment activity. Different research assays have been proposed and, although two PCR-based research use only investigational assays have been developed, the lack of standardized protocols represents an important limitation. Here we have designed and generated a stable clonal cell line producing an RNA-based standard for the calibration of PCR-based circulating HBV RNA assays.

Methods

HBV RNA-producing Huh7-derived stable cell lines were generated by transfecting pTriEX plasmids containing 1.1 unit length HBV DNA genomes carrying mutations in the catalytic site (YMAA mutation) and the TP domain (Y63F) of the polymerase, and the ε-loop of the pregenomic (pg)RNA (mutation A1G).

Results

The clonal cell line (Huh7-3D29), carrying a double YMAA and Y63F mutation, displayed, and maintained over several passages in culture, a high RNA secretion phenotype with negligible residual secreted HBV DNA. Density gradient centrifugation showed that most of the secreted HBV RNA from Huh7-3D29 cells was detected in naked capsid and virion-like particles and only a minority in small extracellular vescicles. Nanopore sequencing of 5’RACE products shows that the majority of the Huh7-3D29-secreted HBV RNAs start at the 5' end of pgRNA and pgRNA-derived spliced RNAs. Finally, Huh7-3D29 cells showed a high and up-scalable secreted RNA yield allowing 1,300 standard curves in 9 days from one flask.

Conclusion

We generated a clonal cell line that produces high quantities of HBV RNAs with very low quantities of contaminating HBV DNAs, representing a stable source of RNA standard for HBV RNA assay calibration.

Impact and implications:

Several investigational assays and two research use only assays have been developed to detect and quantify circulating HBV RNAs, an emerging biomarker of covalently closed circular DNA transcriptional activity and target engagement by new HBV treatments. The lack of a unique molecular standard for circulating HBV RNA quantification represents an important limitation. Here we describe the generation of a stable clonal cell line producing and secreting an RNA-based standard containing all the HBV RNA species found in HBV patients’ sera (e.g. pgRNA, HBx transcripts). This new RNA standard can be used to calibrate all PCR-based assays for circulating HBV RNA quantification to evaluate, in a non-invasive manner, the size of the transcriptionally active cccDNA pool and the activity of novel strategies aimed at curing HBV infection.

Background & Aims

A goal of the World Health Organization’s global hepatitis strategy is the elimination of chronic hepatitis C virus (HCV) infection by 2030. As part of its strategy, the Federal Joint Committee (Germany) decided to include hepatitis B and C screening in a preventive medical examination, which is performed at the primary care level in Germany. We investigated the results 1 year after implementation of screening between October 2021 and September 2022.

Methods

HBsAg/HBV DNA and anti-HCV/HCV RNA screenings were identified by billing categories in 286,192 individuals of 11 ambulatory healthcare centers.

Results

Compared to 30,106 HBsAg and 31,266 anti-HCV laboratory requisitions in the year 2018, the number of tests increased to 286,192 during the screening period. Compared to routine care, additional anti-HCV positive tests age dependently increased the tally by 98% (177 plus 170 positive cases in males) and 123% (96 plus 118 positive cases in females) in those aged 35-44 years up to 518% (17 plus 88 positive cases in males) and 514% (29 plus 149 positive cases in females) in those aged 75-84 years. Similar results were observed for HBsAg. Prevalences of HBsAg, anti-HCV and HCV RNA were 0.54%, 0.79% and 0.13%, respectively.

Conclusions

A structured hepatitis screening program at the primary care level has been successfully established and leads to age- and-sex-dependent large additional effects compared to routine care.

Impact and implications

Strategies to eliminate chronic hepatitis B and C virus infection are country specific and vary between clinical scenarios. Our analysis proves the efficacy of a screening program by primary care physicians compared to routine care in a low-prevalence country. This program should be accompanied by additional efforts in risk populations like people who inject drugs who are under-represented in the current screening approach.

Background & Aims

HBV treatment is challenging due to the persistence of the covalently closed circular DNA replication pool, which remains unaffected by antiviral intervention. In this study, we determined whether targeting antigen-presenting cells via CD40 stimulation represents an appropriate therapeutic approach for achieving sustained HBV control in a mouse model of HBV replication.

Methods

Mice were transduced with an adeno-associated virus encoding the HBV genome (AAV-HBV) to initiate HBV replication and were administered agonistic CD40 antibody. CD4-depleting antibody was administered in addition to the CD40 antibody. Viral antigens in the blood were measured over time to determine HBV control. HBV-specific CD8⁺ T cells were quantified in the spleen and liver at the experimental endpoint.

Results

CD40 stimulation in CD4-depleted AAV-HBV mice resulted in the clearance of HBsAg and HBeAg, along with a reduction in liver HBV mRNA, contrasting with CD4-competent counterparts. CD8⁺ T cells were indispensable for CD40-mediated HBV control, determined by HBV persistence following their depletion. In CD4-replete mice, CD40 stimulation initially facilitated the expansion of HBV-specific CD8⁺ T cells, which subsequently could not control HBV. Finally, α-CD4/CD40 treatment reduced antigenemia and liver HBV mRNA levels in chronic AAV-HBV mice, with further enhancement through synergy with immunization by VSV-MHBs (vesicular stomatitis virus expressing middle HBsAg).

Conclusions

Our findings underscore the potential of CD40 stimulation as a targeted therapeutic strategy for achieving sustained HBV control and reveal a CD4⁺ T cell-dependent limitation on CD40-mediated antiviral efficacy.

Impact and implications:

Immunotherapy has the potential to overcome immune dysfunction in chronic HBV infection. Using a mouse model of HBV replication, this study shows that CD40 stimulation can induce sustained HBV control, which is dependent on CD8⁺ T cells and further enhanced by co-immunization. Unexpectedly, CD40-mediated HBV reduction was improved by the depletion of CD4⁺ cells. These findings suggest potential strategies for reversing HBV persistence in infected individuals.

Cirrhosis is a major health concern worldwide with a complex pathophysiology affecting various biological systems, including all aspects of haemostasis. Bleeding risk is mainly driven by portal hypertension, but in end-stage liver disease it is further increased by alterations in haemostatic components, including platelet function, coagulation, and fibrinolysis. Concurrently, patients with cirrhosis are prone to venous thromboembolic events (VTE) because of the altered haemostatic balance, in particular an increase in thrombin generation. In patients with cirrhosis, vitamin K antagonists (VKA) and low molecular weight heparins (LMWH) are currently the standard of care for VTE prevention, with VKA also being standard of care for stroke prevention in those with atrial fibrillation. However, direct oral anticoagulants (DOAC) could have specific advantages in this patient population. Clinical experience suggests that DOAC are a safe and possibly more effective alternative to traditional anticoagulants for the treatment of VTE in patients with compensated cirrhosis. In addition, emerging data suggest that primary prophylactic treatment with anticoagulants may improve clinical outcomes in patients with cirrhosis by reducing the risk of hepatic decompensation. The selection of the most appropriate DOAC remains to be clarified. This review focuses on the rationale for the use of DOAC in patients with cirrhosis, the specific effects of the different DOAC (as assessed by in vitro and in vivo pharmacokinetic and pharmacodynamic studies), as well as clinical outcomes in patients with cirrhosis on DOAC.

Background & Aims

The homeostasis of the cellular transcriptome depends on transcription and splicing mechanisms. Moreover, the fidelity of gene expression, essential to preserve cellular identity and function is secured by different quality control mechanisms including nonsense-mediated RNA decay (NMD). In this context, alternative splicing is coupled to NMD, and several alterations in these mechanisms leading to the accumulation of aberrant gene isoforms are known to be involved in human disease including cancer.

Methods

RNA sequencing, western blotting, qPCR and co-immunoprecipitation were performed in multiple silenced culture cell lines (replicates n ≥4), primary hepatocytes and samples of animal models (Jo2, APAP, Mdr2^-/- mice, n ≥3).

Results

Here we show that in animal models of liver injury and in human HCC (TCGA, non-tumoral = 50 vs. HCC = 374), the process of NMD is inhibited. Moreover, we demonstrate that the splicing factor SLU7 interacts with and preserves the levels of the NMD effector UPF1, and that SLU7 is required for correct NMD. Our previous findings demonstrated that SLU7 expression is reduced in the diseased liver, contributing to hepatocellular dedifferentiation and genome instability during disease progression. Here we build on this by providing evidence that caspases activated during liver damage are responsible for the cleavage and degradation of SLU7.

Conclusions

Here we identify the downregulation of UPF1 and the inhibition of NMD as a new molecular pathway contributing to the malignant reshaping of the liver transcriptome. Moreover, and importantly, we uncover caspase activation as the mechanism responsible for the downregulation of SLU7 expression during liver disease progression, which is a new link between apoptosis and hepatocarcinogenesis.

Impact and implications:

The mechanisms involved in reshaping the hepatocellular transcriptome and thereby driving the progressive loss of cell identity and function in liver disease are not completely understood. In this context, we provide evidence on the impairment of a key mRNA surveillance mechanism known as nonsense-mediated mRNA decay (NMD). Mechanistically, we uncover a novel role for the splicing factor SLU7 in the regulation of NMD, including its ability to interact and preserve the levels of the key NMD factor UPF1. Moreover, we demonstrate that the activation of caspases during liver damage mediates SLU7 and UPF1 protein degradation and NMD inhibition. Our findings identify potential new markers of liver disease progression, and SLU7 as a novel therapeutic target to prevent the functional decay of the chronically injured organ.

Background & Aims

People who drink alcohol excessively are at increased risk of developing metabolic dysfunction and alcohol-related liver disease (MetALD) or the more severe form alcohol-related liver disease (ALD). One of the most significant challenges concerns the early detection of MetALD/ALD. Previously, we have demonstrated that the lysosomal enzyme cathepsin D (CTSD) is an early marker for metabolic dysfunction-associated steatohepatitis (MASH). Here, we hypothesized that plasma CTSD can also serve as an early indicator of MetALD/ALD.

Methods

We included 303 persistent heavy drinkers classified as having MetALD or ALD (n = 152) and abstinent patients with a history of excessive drinking (n = 151). Plasma CTSD levels of patients with MetALD/ALD without decompensation were compared with 40 healthy controls. Subsequently, the relationship between plasma CTSD levels and hepatic histological scores was established. Receiver-operating characteristic curves were generated to assess the precision of plasma CTSD levels in detecting MetALD/ALD. Lastly, plasma CTSD levels were compared between abstainers and drinkers.

Results

Plasma CTSD levels were higher in patients with MetALD/ALD compared to healthy controls. While hepatic disease parameters (AST/ALT ratio, liver stiffness measurement) were higher at advanced histopathological stages (assessed by liver biopsy), plasma CTSD levels were already elevated at early histopathological stages. Furthermore, combining plasma CTSD levels with liver stiffness measurement and AST/ALT ratio yielded enhanced diagnostic precision (AUC 0.872) in detecting MetALD/ALD in contrast to the utilization of CTSD alone (AUC 0.804). Plasma CTSD levels remained elevated in abstainers.

Conclusion

Elevated levels of CTSD in the circulation can serve as an early indicator of MetALD/ALD.

Impact and implications:

Alcohol-related liver disease is the leading cause of liver disease-related morbidity and mortality worldwide. However, the currently available non-invasive methods to diagnose MetALD/ALD are only able to detect advanced stages of MetALD/ALD. Here, we demonstrate that plasma levels of the lysosomal enzyme cathepsin D are already elevated at early stages of MetALD/ALD. Moreover, cathepsin D levels outperformed the currently available non-invasive methods to detect MetALD/ALD. Plasma levels of cathepsin D could therefore be a useful non-invasive marker for detection of MetALD/ALD.

Background & Aims

Sarcopenia is associated with increased morbidity and mortality in patients with cirrhosis, but its definition in current literature is very heterogeneous. We performed a systematic review and meta-analysis to assess the association between mortality and sarcopenia evaluated by computed tomography (CT) in patients with cirrhosis, both overall and stratified for the criteria used to define sarcopenia.

Methods

Medline, Embase, Scopus, and Cochrane Library were searched up to January 2023. We included studies assessing sarcopenia presence with CT scans and providing data on the risk of mortality. Adjusted hazard ratios (HRs) and 95% CIs were pooled using a random-effects model.

Results

Thirty-nine studies comprising 12,827 patients were included in the meta-analysis. The summary prevalence of sarcopenia was 44% (95% CI 38-50%). The presence of sarcopenia (any definition) was an independent predictor of mortality with an adjusted HR of 2.07 (95% CI 1.81-2.36), and the result was consistent in all subgroup analyses. The prognostic role of the EASL/AASLD criteria was confirmed for the first time with an HR of 1.86 (95% CI 1.53-2.26) (n = 14 studies). The cut-offs used to define sarcopenia based on psoas muscle parameters varied among studies, thus, a subgroup analysis was not feasible. There was no substantial heterogeneity for the main estimates and no significant risk of publication bias.

Conclusions

Sarcopenia on CT is associated with a 2-fold higher risk of mortality in patients with cirrhosis. The cut-offs proposed by EASL/AASLD are prognostically relevant and should be the recommended criteria used to define sarcopenia in clinical practice.

Impact and implications:

Sarcopenia assessed by the reference standard (computed tomography scan) is an independent predictor of mortality in patients with cirrhosis, with a 2-fold increase in the risk of death in all sensitivity analyses. This finding is particularly valid in patients from Europe and North America, and in transplant candidates. Stratifying for the parameters and cut-offs used, we confirmed for the first time the prognostic impact of the definition proposed by EASL/AASLD, supporting their use in clinical practice. Psoas muscle assessment is promising, but data are still limited and too heterogeneous to recommend its routine use at present.