Integrin β1 Promotes Peripheral Entry by Rabies Virus

Abstract

Rabies virus (RABV) is a widespread pathogen that causes fatal disease in humans and animals. It has been suggested that multiple host factors are involved in RABV host entry. Here, we showed that RABV uses integrin β1 (ITGB1) for cellular entry. RABV infection was drastically decreased after ITGB1 short interfering RNA knockdown and moderately increased after ITGB1 overexpression in cells. ITGB1 directly interacts with RABV glycoprotein. Upon infection, ITGB1 is internalized into cells and transported to late endosomes together with RABV. The infectivity of cell-adapted RABV in cells and street RABV in mice was neutralized by ITGB1 ectodomain soluble protein. The role of ITGB1 in RABV infection depends on interaction with fibronectin in cells and mice. We found that Arg-Gly-Asp (RGD) peptide and antibody to ITGB1 significantly blocked RABV infection in cells in vitro and street RABV infection in mice via intramuscular inoculation but not the intracerebral route. ITGB1 also interacts with nicotinic acetylcholine receptor, which is the proposed receptor for peripheral RABV infection. Our findings suggest that ITGB1 is a key cellular factor for RABV peripheral entry and is a potential therapeutic target for postexposure treatment against rabies. IMPORTANCE Rabies is a severe zoonotic disease caused by rabies virus (RABV). However, the nature of RABV entry remains unclear, which has hindered the development of therapy for rabies. It is suggested that modulations of RABV glycoprotein and multiple host factors are responsible for RABV invasion. Here, we showed that integrin β1 (ITGB1) directly interacts with RABV glycoprotein, and both proteins are internalized together into host cells. Differential expression of ITGB1 in mature muscle and cerebral cortex of mice led to A-4 (ITGB1-specific antibody), and RGD peptide (competitive inhibitor for interaction between ITGB1 and fibronectin) blocked street RABV infection via intramuscular but not intracerebral inoculation in mice, suggesting that ITGB1 plays a role in RABV peripheral entry. Our study revealed this distinct cellular factor in RABV infection, which may be an attractive target for therapeutic intervention.

Structural and Evolutionary Insights Into the Binding of Host Receptors by the Rabies Virus Glycoprotein

“…In the current study, we analyzed the proteinprotein interactions between the RV-G protein and ITGB1 in different species (Figures 3A-C). Results obtained from ITGB1 and RV-G protein docking are consistent with previous studies which identified that the interaction site between ITGB1 and RV-G protein within residues 1-728 a.a on the ITGB1 ectodomain (Shuai et al, 2019). Also, our analysis showed that the G protein ectodomain was the interacting site with ITGB1 in human, dog, and bat.…”

“…Both dog and black fruit bat showed nine a.a. residue difference in the tail domain relative to human. The differences in these residues (1-728 a.a) may be crucial, since the ITGB1 ectodomain constitutes the interaction site with the RV-G protein, as was pointed out in a previous study (Shuai et al, 2019). Our results highlight the sequence homology within the mGluR2 protein alignment among the different species (Figure 2B).…”

Integrative Network Biology Framework Elucidates Molecular Mechanisms of SARS-CoV-2 Pathogenesis

“…It also remains to be demonstrated whether viral entry through different receptors is context dependent. Another CSP Integrin β1 encoded by ITGB1 was recently shown to be required for the entry of rabies virus ( Shuai et al., 2020 ). Whether ITGB1 could also promote the entry of SARS-CoV-2 is another question that needs to be addressed.…”

Integrative Network Biology Framework Elucidates Molecular Mechanisms of SARS-CoV-2 Pathogenesis

“…Therefore, it is plausible that under certain physiological conditions when SARS-CoV-2 does not engage with the ACE2 receptor for its entry into the cell, PHB serves as an alternative receptor. Another CSP Integrin β1 encoded by ITGB1 was recently shown to be required for the entry of Rabies Virus 57 Whether ITGB1 could also promote the entry of SARS-CoV-2 is another question that needs to be addressed. MEPCE is another important enzyme involved in RNA stabilization by capping the 5’ end of RNA with methyl phosphate 58 .…”