Differential Activity of Repurposed Drugs as Receptor Binding Domain Antagonists for Omicron and Native Strains of SarsCov2

Omicron strain is the latest variant of concern of SarsCov2 virus. The mutations in this strain in the S protein Receptor Binding domain (RBD) enable it to be more transmissible as well as escape neutralizing activity by antibodies in response to vaccine. Thus, Omicron specific strategies are need to counter infection by this strain. We investigated a collection of approved drugs shown to antagonize the binding of native strain RBD to human ACE2, for their ability to antagonize binding to Omicron strain RBD. While most of the drugs the drugs that antagonize binding to native RBD are also active for Omicron RBD but some were inactive, namely drugs that contain iodine are completely inactive against Omicron RBD. Our data strongly indicate that presence of a single iodine molecule in the drug renders it inactive against Omicron strain. Thus, there is molecular specificity of drugs for antagonizing Omicron strain RBD versus native strain RBD of this virus. Such information will pave way for specific drugs for Omicron. A pragmatic message from our data is that the often-used iodine containing mouth wash and rises may be ineffective in antagonizing receptor binding of Omicron strain.

Edible formulations of chicken egg derived IgY antibodies neutralize SarsCoV2 Omicron RBD binding to human ACE2

SarsCoV2 virus driven pandemic continues to surge propelled by new mutations such as seen in Omicron strain. Omicron is now rapidly becoming the dominant strain globally with more than 30 mutations in the spike protein. The mutations have resulted in Omicron strain escaping most of the neutralizing antibodies generated by the current set of approved vaccines and diluting the protection offered by the vaccines and therapeutic monoclonal antibodies. This has necessitated the need for newer strategies to prevent this strain from spreading. Towards this unmet need we have developed chicken egg derived anti-RBD IgY antibodies that neutralize the binding of Omicron RBD to human ACE2. Furthermore, we have formulated the edible IgY as flavored beverages to allow for use as oral rinse and prevent the entry of Omicron in the oropharyngeal passage, a major access and accumulation point for this strain in humans.

Preparation of ingestible antibodies to neutralize the binding of SarsCoV2 RBD (receptor binding domain) to human ACE2 Receptor

COVID19 continues to be a serious threat to human health and mortality. There is dire need for new solutions to combat this pandemic especially for those individuals who are not vaccinated or unable to be vaccinated and continue to be exposed to the SARSCoV2. In addition, the emergence of new more transmissible variants such as delta pose additional threat from this virus. To explore another solution for prevention and treatment of COVID 19, we have produced chicken egg derived IgY antibodies against the Receptor binding domain (RBD) of SARSCoV2 spike protein which is involved in binding to human cell ACE2 receptors. The - RBD IgY effectively neutralize the binding of RBD to ACE2 and prevent pseudovirus entry in a PRNT assay. Importantly our anti-RBD IgY also neutralize the binding of Sars CoV2 delta variant RBD to ACE2. Given that chicken egg derived IgY are safe and permissible for human consumption, we plan to develop these ingestible antibodies for prevention of viral entry in the oropharyngeal and digestive tract in humans as passive immunotherapy.

Identification of SGLT2 inhibitor Ertugliflozin as a treatment for COVID-19 using computational and experimental paradigm

Drug repurposing can expedite the process of drug development by identifying known drugs which are effective against SARS-CoV-2. The RBD domain of SARS-CoV-2 Spike protein is a promising drug target due to its pivotal role in viral-host attachment. These specific structural domains can be targeted with small molecules or drug to disrupt the viral attachment to the host proteins. In this study, FDA approved Drugbank database were screened using a virtual screening approach and computational chemistry methods. Five drugs were short listed for further profiling based on docking score and binding energies. Further these selected drugs were tested for their in vitro biological activity. There was significant correlation between the prediction from computational studies and the actual RBD-ACE2 binding inhibition by the drugs. Then, we performed a series of studies that mimic some of the biological events seen in COVID-19 patients such as secretion of IL1{beta}, presentation of a more thrombogenic endothelium by production of thrombomodulin and accumulation of inflammatory cells such as monocytes in the lungs. Of all the drugs, most promising drug was Ertugliflozin which is used for type-2 diabetes. This drug possesses several desired properties and may be a good candidate for immediate repurposing for treatment of COVID-19.

In silico and in vitro Demonstration of Homoharrintonine Antagonism of RBD-ACE2 Binding and its Anti-inflammatory and anti-thrombogenic Properties in a 3D human vascular lung model

Since 2019 the world has seen severe onslaught of SARS-CoV-2 viral pandemic. There is an urgent need for drugs that can be used to either prevent or treat the potentially fatal disease COVD-19. To this end, we screened FDA approved antiviral drugs which could be repurposed for COVID-19 through molecular docking approach in the various active sites of receptor binding domain (RBD). The RBD domain of SARS-CoV-2 spike protein is a promising drug target due to its pivotal role in viral-host attachment. Specifically, we focussed on identifying antiviral drugs which could a) block the entry of virus into host cells, b) demonstrate anti-inflammatory and/or anti-thrombogenic properties. Drugs which poses both properties could be useful for prevention and treatment of the disease. While we prioritized a few antiviral drugs based on molecular docking, corroboration with in vitro studies including a new 3D human vascular lung model strongly supported the potential of Homoharringtonine, a drug approved for chronic myeloid leukaemia to be repurposed for COVID-19. This natural product drug not only antagonized the biding of SARS-CoV-2 spike protein RBD binding to human angiotensin receptor 2 (ACE-2) protein but also demonstrated for the first time anti-thrombogenic and anti-leukocyte adhesive properties in a human cell model system. Overall, this work provides an important lead for development of rapid treatment of COVID-19 and also establishes a screening paradigm using molecular modelling and 3D human vascular lung model of disease to identify drugs with multiple desirable properties for prevention and treatment of COVID-19.

Tyrosine Kinase Inhibitor Family of Drugs as Prospective Targeted Therapy for COVID-19 Based on In Silico And 3D-Human Vascular Lung Model Studies

COVID-19 pandemic has ravaged the world and vaccines have been rapidly developed as preventive measures. But there is no target-based therapy which can be used if infection sets in. Remdesiver and dexamethasone were not designed to combat COVID-19 but are used clinically till better targeted therapies are available. Given this situation target based therapies that intervene in the disease pathway are urgently needed. Since COVID-19 genesis is driven by uncontrolled inflammation/thrombosis and protein kinases are critical in mounting this response, we explored if available tyrosine kinase inhibitors (TKIs) can be used as intervention. We profiled four TKIs namely; Lapatinib, Dasatinib, Pazopanib and Sitravatinib which inhibit tyrosine kinases but are completely distinct in their chemical structures. We demonstrate using in silico and an in vitro 3D-human vascular lung model which profiles anti-inflammatory and anti-thrombogenic properties that all four TKIs are active in varying degrees. Our findings that chemically different TKIs which share kinase inhibition as the common mechanism of action are active, strongly indicates that its a tyrosine kinase target-based activity and not off-target arbitrary effect. We propose that TKIs, approved for human use and widely available, can be rapidly deployed as specific target-based therapy for COVID-19.