Hepatitis D virus infection, innate immune response and antiviral treatments in stem cell‐derived hepatocytes

Abstract

BackgroundHuman pluripotent stem cell (hPSC)‐derived hepatocyte‐like cells (HLCs) are a valuable model to investigate host‐pathogen interactions of hepatitis viruses in a mature and authentic environment. Here, we investigate the susceptibility of HLCs to the hepatitis delta virus (HDV).MethodsWe differentiated hPSC into HLCs, and inoculated them with infectious HDV produced in Huh7NTCP. HDV infection and cellular response was monitored by RTqPCR and immunostaining.ResultsCells undergoing hepatic differentiation become susceptible to HDV after acquiring expression of the viral receptor Na+‐taurocholate co‐transporting polypeptide (NTCP) during hepatic specification. Inoculation of HLCs with HDV leads to detection of intracellular HDV RNA and accumulation of the HDV antigen in the cells. Upon infection, the HLCs mounted an innate immune response based on induction of the interferons IFNB and L, and upregulation of interferon‐stimulated genes. The intensity of this immune response positively correlated with the level of viral replication and was dependant on both the JAK/STAT and NFκB pathway activation. Importantly, this innate immune response did not inhibit HDV replication. However, pre‐treatment of the HLCs with IFNα2b reduced viral infection, suggesting that ISGs may limit early stages of infection. Myrcludex efficiently abrogated infection and blocked innate immune activation. Lonafarnib treatment of HDV mono infected HLCs on the other hand led to exacerbated viral replication and innate immune response.ConclusionThe HDV in vitro mono‐infection model represents a new tool to study HDV replication, its host‐pathogen interactions and evaluate new antiviral drugs in cells displaying mature hepatic functions.

Human pluripotent stem cell-derived hepatocyte-like cells for hepatitis D virus studies

“…This may be due to the observation that LNF enhances primary infections (Fig. 2D) which is in agreement with reports by others 23,45 . Of note, the high dose of BLV completely abrogated secondary infection of Huh7 NTCP cells (Fig.…”

“…This early expression of NTCP rendered hepatic progenitors susceptible to HDV infection, aligning with previous studies that showed non-hepatic cell lines becoming susceptible to HDV infection upon ectopic NTCP expression 11 . In agreement, we found stem cells to be already capable of replicating the HDV genome when delivered through transfection, bypassing the entry step, which is consistent with the findings by Lange et al 45…”

“…This early expression of NTCP rendered hepatic progenitors susceptible to HDV infection, aligning with previous studies that showed non-hepatic cell lines becoming susceptible to HDV infection upon ectopic NTCP expression 11 . In agreement, we found stem cells to be already capable of replicating the HDV genome when delivered through transfection, bypassing the entry step, which is consistent with the findings by Lange et al 45 Surprisingly, we discovered that fully matured HLCs at day 18 of differentiation exhibited a higher susceptibility to HDV infection compared to less mature cells. This suggested the presence of one or several hepatocyte-specific co-factors that facilitated HDV entry or replication.…”

“…During the work on this manuscript, a study by Lange and colleagues 45 used HLCs to study the innate immune responses to HDV mono-infection. Here, in contrast, we studied HDV biology in the context of its helper virus.…”