Coronavirus disease 2019 (COVID-19) has reached pandemic proportions. Pulmonary and kidney disease are highly prevalent serious consequences of infection with SARS-CoV-2. Kidney Injury Molecule-1 (KIM-1) was identified by Drs Bonventre and Ichimura as the most upregulated protein in the injured kidney proximal tubule. KIM-1, also called TIM-1, is a receptor for hepatitis A, Ebola, Dengue and possibly SARS-CoV1 viruses. We hypothesize that KIM-1 is a receptor for SARS-CoV-2 both in renal tubule epithelial cells and in airway epithelial cells and that JB1, our newly discovered small molecule inhibitor of KIM-1, and/or nanodisc- incorporated KIM-1 ectodomain can be prophylactic and therapeutic agents for COVID-19. We also hypothesize that we can use the high-affinity binding of KIM-1 and ACE2 to the virus to create novel diagnostic devices for the virus.
In Specific Aim 1 we will characterize the role of KIM-1 in promoting SARS-CoV-2 entry into kidney and lung epithelia using kidney microphysiological analysis platforms (MAPs) on chip and develop an ultrasensitive chip for the high-throughput evaluation of potential SARS-CoV-2 binding inhibitors. KIM-1 and ACE2 mediated endocytosis of SARS-CoV-2 biomimetic viruses (virosomes) will be compared in kidney and lung epithelial cells. We will evaluate the effects of KIM-1-mediated spike proteins or biomimetic virus cellular adhesion and uptake on production of paracrine factors which activate endothelial cells using a kidney-lung MAP. In order to understand binding and/or uptake kinetics of SARS-CoV-2 and characterize potential inhibitors we will develop an ultrasensitive nanoplasmonic triplets-based rapid lateral flow diagnostic chip for a rapid and sensitive inhibition assay using the kidney-lung MAP. This approach can also be used for point of care diagnostic testing for the virus.
In Specific Aim 2 we will evaluate the efficacy of JB1, soluble KIM-1 ectodomain and nanodisc-incorporated KIM-1 or ACE2 to inhibit binding and internalization of SARS-CoV-2 biomimetic viruses by kidney and lung cells using an integrated lung-kidney MAP on chip. Potential inhibitors will be tested to evaluate whether they compete with S-protein and/or biomimetic virus binding and reduce IL-6 production. Binding affinity and kinetics between KIM-1 variants or ACE2 either as free ectodomains or incorporated into nanodiscs and the Spike protein will be measured using MicroScale Thermophoresis (MST) and Biolayer Interferometry.
The proposed work will take advantage of new technologies in stem cell biology, microfabrication, and microfluidics to characterize the role of Kidney Injury Molecule-1 (KIM-1) as a receptor for SARS-Co-2, the virus responsible for COVID-19. In addition, we will create a novel device to test for inhibitors of interactions of the virus with lung and kidney cells that will inform therapies to prevent and treat the disease. We will test whether nanodiscs with KIM-1 embedded, can prevent binding of the virus to angiotensin converting enzyme 2 (ACE2) on cells and hence be a therapeutic candidate for this devastating disease.
