Hepatitis C virus (HCV) is an important and underreported infectious disease, causing chronic infection in ~71
million people worldwide. The CDC estimates there are ~30,000 new cases of HCV every year in the US and
about 20,000 deaths annually, making HCV more deadly than 60 other infectious diseases combined, including
HIV. However, the underlying mechanisms that lead to chronic HCV infection followed by end-stage liver disease
are poorly understood. Although chronic hepatitis C can now be effectively treated with direct-acting antivirals
(DAAs), a vaccine to prevent transmission remains a high priority due to extremely high treatment costs
($80,000+ for a 12-week course). Furthermore, once infected, individuals remain at high risk for liver disease
even post-treatment. The proposed work will build on our substantial research findings to continue systematically
analyzing the mechanisms that create barriers to interspecies HCV transmission.
Aim 1: Define mechanisms of known host factors from diverse species that support HCV replication.
HCV relies on a variety of host factors to establish replication in hepatocytes. Our preliminary data demonstrate
that for all great apes tested, orthologs of peptidylprolyl isomerase A, also known as cyclophilin A (CypA), support
HCV RNA replication. However, CypA of distantly related species, such as New and Old World monkeys and
mice, is far less efficient. We aim to define mechanistically the underlying incompatibility of this and other host
factors with the virally encoded components of the HCV replication machinery.
Aim 2: Characterize HCV infection and immune response networks following infection across primate
and rodent species. We will study whether HCV can infect and replicate in a novel set of stem cell-derived
hepatocyte-like cells from a range of evolutionarily diverse species, including great apes, selected New and Old
World monkeys and rodents. In a second step, we will use high-throughput single-cell RNA sequencing to derive
species-specific transcriptomic response networks associated with HCV replication.
Aim 3: Characterize the impact of CD302 and Cr1L on restricting HCV infection in vivo. Human entry factor
transgenic mice with blunted innate immunity only support low-level viral replication, suggesting murine
restriction factors may suppress viral replication in vivo. Our preliminary data indicate mouse CD302 and
complement component (3b/4b) receptor 1-like (Cr1L) limit HCV replication in vitro. Here, we will assess if loss-
of-function of mCD302 and mCr1L augments HCV infection in our HCV entry factor knock-in mice.
The proposed work will provide new insights into the species tropism of HCV. The Ploss lab has made many
seminal contributions to the field and will be aided in this important work by our long-standing collaborators Drs.
Schwartz (Weill Cornell), Shalek (MIT) and Pietschmann (Twincore, Germany). Our work will advance the field
of HCV research by making progress in the development of small animal models suitable for studying HCV
infection and immune responses, a necessary precursor to improving treatment and developing vaccines.