Interaction between TIM-1 and NPC1 Is Important for Cellular Entry of Ebola Virus

Abstract

Multiple host molecules are known to be involved in the cellular entry of filoviruses, including Ebola virus (EBOV); T-cell immunoglobulin and mucin domain 1 (TIM-1) and Niemann-Pick C1 (NPC1) have been identified as attachment and fusion receptors, respectively. However, the molecular mechanisms underlying the entry process have not been fully understood. We found that TIM-1 and NPC1 colocalized and interacted in the intracellular vesicles where EBOV glycoprotein (GP)-mediated membrane fusion occurred. Interestingly, a TIM-1-specific monoclonal antibody (MAb), M224/1, prevented GP-mediated membrane fusion and also interfered with the binding of TIM-1 to NPC1, suggesting that the interaction between TIM-1 and NPC1 is important for filovirus membrane fusion. Moreover, MAb M224/1 efficiently inhibited the cellular entry of viruses from all known filovirus species. These data suggest a novel mechanism underlying filovirus membrane fusion and provide a potential cellular target for antiviral compounds that can be universally used against filovirus infections. IMPORTANCE Filoviruses, including Ebola and Marburg viruses, cause rapidly fatal diseases in humans and nonhuman primates.There are currently no approved vaccines or therapeutics for filovirus diseases. In general, the cellular entry step of viruses is one of the key mechanisms to develop antiviral strategies. However, the molecular mechanisms underlying the entry process of filoviruses have not been fully understood. In this study, we demonstrate that TIM-1 and NPC1, which serve as attachment and fusion receptors for filovirus entry, interact in the intracellular vesicles where Ebola virus GP-mediated membrane fusion occurs and that this interaction is important for filovirus infection. We found that filovirus infection and GP-mediated membrane fusion in cultured cells were remarkably suppressed by treatment with a TIM-1-specific monoclonal antibody that interfered with the interaction between TIM-1 and NPC1. Our data provide new insights for the development of antiviral compounds that can be universally used against filovirus infections.

Kidney Injury Marker 1 and Neutrophil Gelatinase-Associated Lipocalin in Chronic Kidney Disease

“…KIM-1 is a cell surface receptor in epithelial and lymphoid/myeloid cells. It behaves as a scavenger receptor for oxidized LDL and phosphatidylserine and as Ebola and Hepatitis A virus entry receptor in epithelial cells [2] . Kim-1 binding to phosphatidylserine allows the phagocytosis of apoptotic cells.…”

“…As an example, kidney injury in non-albuminuric CKD (e.g. certain tubulointerstitial and vascular nephropathies) is not represented in the glomerular-based risk categorization until eGFR falls <60 ml/ min/1.73 m 2 . Tubular injury markers may be better suited for risk categorization in early stages in these patients.…”

Chemically Modified Human Serum Albumin Potently Blocks Entry of Ebola Pseudoviruses and Viruslike Particles

“…It has been demonstrated that EBOV GP-mediated viral entry consists of at least five steps, including cell surface attachment, endocytosis, cathepsin cleavage of GP, fusion receptor binding, and membrane fusion (32)(33)(34)(35). The results of the time-of-addition assay in Fig.…”

Technical Considerations for the Generation of Novel Pseudotyped Viruses

“…The use of PVs has been of crucial significance in the rapid pace of research into the Middle Eastern Respiratory syndrome (MERS) outbreak [8][9][10][11]. During the recent Ebola outbreak, PVs were successfully used in high-throughput screening studies that helped in the identification of potential antivirals and filovirus entry inhibitors [12][13][14] as well as in the study of the viral life cycle and virus receptor interaction [15].…”