The most recent outbreak of the Ebola virus (EBOV) epidemic posed a major threat to the world. Because the mechanisms of EBOV infection remain obscure, there is still no specific treatment or vaccine for EBOV disease. While EBOV-host cell attachment has been shown to depend critically on the molecular biomechanics of interaction between receptors on the cell surface and the outer coat of the virus, the quantitative understanding essential for guiding the development of therapies is completely lacking. Recent work has established the importance of TIM family proteins and the geometry and mechanical properties of its mucin-like stalk domain (MLD). However, further progress building on these recent findings requires expertise in experimental and theoretical molecular biomechanics, different than that which has advanced our knowledge so far. This proposal takes advantage of the PIs’ capabilities in single-molecule force spectroscopy (Zhang) and computational molecular adhesion mechanics (Jagota) to address the problem of establishing quantitative understanding of the molecular, cellular, and biomechanical mechanisms of EBOV attachment to a host cell. We hypothesize that quantitative knowledge about the biomechanical properties of the stalk presenting the ligand binding IgV domain, i.e., the length, rigidity and charge of the MLD of TIM, can be used to predict conditions for EBOV attachment. Aim 1 will utilize single-molecular force spectroscopy to characterize experimentally how TIM family proteins interact with EBOV in a rate- and force- dependent fashion, and how the interaction is influenced by the length, rigidity and charge of MLD. Aim 2 will test the hypothesis by developing biomechanical models that show how single-molecule biomechanical properties, and how the properties of the MLD, such as its length, rigidity, and charge density, control TIM mediated cellular/viral membrane adhesion and engulfment. Model development will be calibrated and validated through single-molecule measurements. The study will elucidate quantitatively—for the first time—the biomechanical mechanism of EBOV–host cell interaction, providing potential new targets for antiviral drug development.

T-cell immunoglobulin and mucin domain (TIM) family proteins serve as cell surface receptors to mediate the attachment of Ebola virus (EBOV) onto human host cells, resulting in subsequent EBOV uptake and infection. The overall goal of this project is to elucidate the biophysical and biomechanical mechanisms underlying the TIM-mediated adhesion and attachment between EBOV and its host cells, and to compare TIM-EBOV interaction to TIM-mediated apoptotic body uptake. The study may provide new pharmacological targets and aid in the development of much-needed new antiviral therapeutics for the prevention and treatment of EBOV disease.