TIM-1 Mediates Dystroglycan-Independent Entry of Lassa Virus

Abstract

Lassa virus (LASV) is an Old World arenavirus responsible for hundreds of thousands of infections in West Africa every year. LASV entry into a variety of cell types is mediated by interactions with glycosyltransferase LARGE-modified O-linked glycans present on the ubiquitous receptor α-dystroglycan (αDG). However, cells lacking αDG are permissive to LASV infection, suggesting that alternative receptors exist. Previous studies demonstrated that the phosphatidylserine (PtdSer)-binding receptors Axl and Tyro3 along with C-type lectin receptors mediate αDG-independent entry. Here, we demonstrate that another PtdSer receptor, TIM-1, mediates LASV glycoprotein (GP)-pseudotyped virion entry into αDG-knocked-out HEK 293T and wild-type (WT) Vero cells, which express αDG lacking appropriate glycosylation. To investigate the mechanism by which TIM-1 mediates enhancement of entry, we demonstrate that mutagenesis of the TIM-1 IgV domain PtdSer-binding pocket abrogated transduction. Furthermore, the human TIM-1 IgV domain-binding monoclonal antibody ARD5 blocked transduction of pseudovirions bearing LASV GP in a dose-dependent manner. Finally, as we showed previously for other viruses that use TIM-1 for entry, a chimeric TIM-1 protein that substitutes the proline-rich region (PRR) from murine leukemia virus envelope (Env) for the mucin-like domain served as a competent receptor. These studies provide evidence that, in the absence of a functional αDG, TIM-1 mediates the entry of LASV pseudoviral particles through interactions of virions with the IgV PtdSer-binding pocket of TIM-1. PtdSer receptors, such as TIM-1, are emerging as critical entry factors for many enveloped viruses. Most recently, hepatitis C virus and Zika virus have been added to a growing list. PtdSer receptors engage with enveloped viruses through the binding of PtdSer embedded in the viral envelope, defining them as GP-independent receptors. This GP-independent entry mechanism should effectively mediate the entry of all enveloped viruses, yet LASV GP-pseudotyped viruses were previously found to be unresponsive to PtdSer receptor enhancement in HEK 293T cells. Here, we demonstrate that LASV pseudovirions can utilize the PtdSer receptor TIM-1 but only in the absence of appropriately glycosylated α-dystroglycan (αDG), the high-affinity cell surface receptor for LASV. Our studies shed light on LASV receptor utilization and explain why previous studies performed with α-DG-expressing cells did not find that LASV pseudovirions utilize PtdSer receptors for virus uptake.

Arbidol and Other Low-Molecular-Weight Drugs That Inhibit Lassa and Ebola Viruses

“…Viral entry inhibitors are valuable as therapeutics, since blocking infection early in the life cycle will reduce cellular and tissue damage associated with the replication of incoming viruses and the production of viral progeny. LASV employs several key features in common with EBOV for its entry: (i) it is internalized into the endocytic pathway by a macropinocytotic-like process after initial contact with surface receptors/ attachment factors, (ii) low pH is needed to trigger fusion, and (iii) an endosomal, cholesterol binding receptor promotes endosomal escape (Lamp1 for LASV and NPC1 for EBOV) (12,(25)(26)(27)(28)(29)(30)(31)(32). Hence, for this study, we selected eight low-molecular-weight drugs shown to inhibit EBOV entry and directly compared their inhibitory activities against LASV and EBOV.…”

Differences in Tissue and Species Tropism of Reptarenavirus Species Studied by Vesicular Stomatitis Virus Pseudotypes

“…The conserved and widely expressed receptor for extracellular matrix proteins, α-dystroglycan (α-DG), is a main receptor for Old World (OW) mammarenaviruses, such as lymphocytic choriomeningitis virus (LCMV) and Lassa virus (LASV) [38]. Secondary alternative receptors, including members of the Tyro3/Axl/Mer and T-cell immunoglobulin mucin (TIM) receptor families may account for LASV and LCMV infection of cells lacking fully glycosylated α-DG [44,45]. Cell entry of the OW hemorrhagic fever (HF) mammarenavirus Lujo virus (LUJV) is mediated by neuropilin (NRP)-2, a cell-surface receptor for semaphorins [46].…”

T-cell immunoglobulin and mucin (TIM) contributes to Hantaan virus entry into human airway epithelial cells

“…In the past years, VSV-derived pseudoviruses were used in multiple studies to evaluate entry factors for hantaviruses, filoviruses and arenavirus among others. The studies demonstrated a very close correlation of pseudovirions with the pathogenic viruses (Kondratowicz, Lennemann et al 2011, Jemielity, Wang et al 2013, Moller-Tank, Kondratowicz et al 2013, Moller-Tank and Maury 2014, Kuroda, Fujikura et al 2015, Riblett, Blomen et al 2016, Brouillette, Phillips et al 2018, Jangra, Herbert et al 2018). Entry of HTNV and ANDV into A549 lung epithelial cells was significantly reduced in presence of anti-hTIM-1 blocking antibody (Fig.…”