<p>  </p> <p>Ebola virus (EBOV) infection remains to be a challenge to human health by its high mortality rate. Though it has been discovered for almost 50 years, there are only two antibody-based therapies approved today, and the mortality rate is still greater than 30% with the treatment. Authentic EBOV studies are strictly limited to biosafety level-4 (BSL-4) labs, which slows the development of treatment. While more simple and safer systems have been developed to understand different stages of EBOV infection, such as the matrix protein (VP40) virus-like particle (VLP) and minigenome systems, we still lack a systematical view of EBOV infection. On the other hand, mathematical modeling has been used to assist biological and medical studies for many years, as it has the advantage of integrating data and providing quantitative insight to a biosystem. In our study, we took advantage of mathematical modeling and build the primary ordinary differential equation-based (ODE-based) model of EBOV at subcellular level step by step. We built the budding pathway of EBOV VP40 first, calibrated and validated our model with experimental data. We proposed that phosphatidylserine (PS) can directly influence the stability of VP40 filaments and the budding process of VLPs. Also, the oligomerization of VP40 filaments may follow the nucleation-elongation process. Next, we conducted in-silico simulation to evaluate the treatment efficiency of fendiline, a drug lowering cell membrane PS level, in treating EBOV. We found that while in general, fendiline can decrease VLP production, there can be fendiline-induced VLP production increases at certain time points due to slow filament growth or fast VLP budding rates. Also, we concluded that fendiline is relatively more effective when applied in the budding stage of EBOV life cycle. Moreover, fendiline efficacy may increase when applied with a VLP budding step targeted treatment. Finally, we integrated nucleoprotein (NP) into our model. We reproduced the two-stage interaction between NP and VP40 and predict that NP increases VLP production through influencing filament oligomerization and VLP budding steps. Also, the dual-effect of NP on VLP production may exist, as a too high NP/VP40 production ratio can decrease VLP production. From the aspect of protein expression time, we found that a bit earlier NP production than VP40 production is beneficial for both inclusion body-containing (IB-containing) VLP production and prevention in energy waste on production of VLPs without IBs. Overall, we have built a solid foundation towards a mathematical EBOV model and demonstrated the value of models in assisting experimental EBOV studies.</p>

<p dir="ltr">The recent global pandemic, COVID-19, has revealed to all the importance of understanding the complex relationship between viruses and hosts. Before COVID-19, I started my study of viral protein-host lipid interactions in the hemorrhagic fevers Ebola and Marburg viruses. These viruses contain a matrix protein that interacts with the plasma membrane to facilitate the formation of both authentic viruses and virus-like particles. My goal was to understand the limitations of their specific host lipid interactions. However, when the COVID-19 pandemic began, so to be our swift response in the development of a biosafety level 2 compatible model. This model can be used for studying severe acute respiratory distress syndrome 2 (SARS-CoV-2) assembly, egress, and entry. This model enabled exponentially greater access to more facilities to study the intricacies of SARS-CoV-2 assembly. With more access to studying the virus in a safe model, our goal is to push the understanding of viral assembly faster. I then began to take apart the individual pieces of the model and started to look at understanding the roles that they play independently. The membrane protein is the most abundant structural protein and I studied the specific lipid interactions of the soluble fraction of the protein. Physicians observed nucleocapsid protein mutations in the clinic with the increasing number of SARS-CoV-2 variants that are on the rise. The microscopy data collected can give us more insight into perhaps how the nucleocapsid protein induces the formation of filopodia structures at the plasma membrane. The envelope protein proved to be a challenge, but I determined a specific envelope and ceramide interaction in cells. The envelope protein was also causing the formation of microvesicles for an undefined function. I was able to determine the subcellular localization of the protein to the mitochondria. The localization to the mitochondria appears to induce depolarization of the mitochondria membrane action potential and induces the increase in mitochondria dysfunction signal, cytochrome c. Although the mitochondria were dysfunctional, there was no increase in apoptosis signal in the presence of the protein alone.</p>