Human TfR1-expressing hamsters to model New World arenaviral hemorrhagic fever - PROJECT SUMMARY
Mammarenaviruses are endemic in rodent populations worldwide and their zoonotic transmission can lead to a
severe life-threatening hemorrhagic fever (HF) syndrome. In the Americas, five New World mammarenaviruses
(NWAs) are known to cause HF. In the absence of FDA-licensed vaccines or antiviral therapies, these viruses
pose a significant public health risk and a threat to national security. Research to understand NWA pathogenesis
and develop effective countermeasures is severely limited by the lack of small-animal models that faithfully mirror
human disease. We recently demonstrated that transgenic expression of human transferrin receptor 1 (huTfR1),
the known cellular receptor used by the pathogenic NWAs, confers susceptibility in mice to lethal disease
following challenge with the Junin arenavirus (JUNV), the agent of Argentine HF. However, the mice do not
manifest signs of hemorrhagic disease that are prominent features of severe cases of NWA HF in humans. We
and others have shown that golden Syrian hamsters infected with related nonpathogenic NWAs that do not use
huTfR1 develop a severe HF-like syndrome with many of the cardinal features of hemorrhagic disease, including
coagulopathy, extensive petechia, bleeding from the oronasal mucosal region and vascular leak. Moreover, we
recently showed that expression of huTfR1 in hamster cell lines significantly augments JUNV infection. Thus,
we hypothesize that hamsters engineered to express huTfR1 will be susceptible to JUNV infection, resulting in
a HF-like syndrome more representative of human disease. To explore this hypothesis, we will pursue the
following Specific Aims: Aim 1. Develop a huTfR1 knock-in (KI) golden Syrian hamster line. We will design
and test single guide (sg)RNAs targeting the 3’ end of the hamster TfR1 gene for insertion of the huTfR1 open
reading frame. By appending the huTfR1 cDNA via a T2A peptide linker immediately before the stop codon of
the hamster TfR1 gene, we will ensure expression of huTfR1 at physiological levels and with normal tissue
distribution. The huTfR1 hamster line will be generated by a well-established pronuclear injection procedure with
the Cas9/sgRNA ribonucleoprotein complex and the huTfR1 cDNA donor construct. Aim 2. Evaluate the
susceptibility of the huTfR1 hamster to JUNV infection. Wild-type and huTfR1 KI hamsters will be challenged
with JUNV to assess differences in viral replication and development of disease. We anticipate that expression
of huTfR1 will boost viral replication leading to a HF-like syndrome in the hamsters. Disease parameters
evaluated daily will include body weight, temperature and clinical disease signs including petechia and mucosal
bleeding. Viral loads will be determined from blood samples taken one week after JUNV challenge, a point at
which huTfR1 hamsters are expected to develop signs of disease and have measurable viremia. The ultimate
goal of this project is to produce a novel hamster model of NWA HF to support development of host-directed
therapies that would complement direct-acting antivirals to improve outcomes in patients suffering from severe
disease caused by pathogenic NWAs.
