Location: Animal Biosciences & Biotechnology Laboratory
Project Number: 8042-31440-002-003-A
Project Type: Cooperative Agreement
Start Date: Jul 25, 2025
End Date: Jul 24, 2029
Objective:
Cooperator aims to further develop B7, a small molecule which can protect pigs against the PURRS virus, the most economically damaging swine virus. Prior, the cooperator has shown the efficacy of the molecule in blocking a receptor critical for infections by PURRS. They also demonstrated the safety of B7 in rats and pigs, and engineered a nanotechnology delivery system for the molecule. Thus, the cooperator proposes to advance the use of B7 as a therapeutic by 1.) molecularly modifying the small molecule to increase its potency and reduce treatment costs; 2) conducting pharmacokinetics characterization and 3) performing in vivo pathogen challenge study in newborn and pregnant pigs to establish B7’s in vivo efficacy.
Approach:
PRRS Aim 1. B7 was found from the AI-screening of 4 million compounds. Meanwhile, ~70 B7 analogs were also obtained. Upon examination of the pathogen inhibitory effects of these analogs, it was found that the 3-(morpholinosulfonyl) anilino moiety and the 3-(piperidinylsulfonyl) anilino moiety are important for B7’s unique function. To further improve B7’s potency, the ~500 million compound database of commercially available small molecules maintained by Molport will be screened. About 100 compounds that retain the above two important function moieties but possess other structural moieties will be purchased. Their anti-infection property in wet-lab experiments as done for B7 will be determined. 2-3 compounds that are more potent than B7 for in vivo lower dosage applications will be identified.
PRRS Aims 2 and 3: For the pharmacokinetics study, B7 or vehicle will be intramuscular injected to weaned piglets and blood samples will be collected at 0, 0.5, 1, 2, 4, 8, 12 and 24 hours after injection. For pathogen challenge, both weaned piglets and late-stage gestational sows will be intranasally inoculated with pathogens and treated with B7 or vehicle. Blood samples will be collected after each B7 treatment until the end of Week 2 (piglets) and 3 (pregnant sows). The pigs will then be necropsied for gross anatomical examination, blood collection, lung lavage and tissue sample collection. Additionally, each day, rectal temperature and score clinical signs including breathing rate, ear discoloration, appetite, symptoms of respiratory and digestive disorders, abortion, etc, will be taken. Veterinarians will be present for cannulations, euthanasia, necropsy and pathological evaluations.
HPLC will be used to determine pharmacokinetics of B7 in plasma. Serum samples and lung lavages will be used to determine the degree of pathogen infection by qRT-PCR. HPLC will also be used to determine the potential accumulation of B7 in organs/tissues. Morphometric scoring of the macro- and microscopic pulmonary/mummified fetal lesions will be conducted by a pathologist collaborator. Comprehensive chemistry and complete blood counts (a total of 32 parameters) will be conducted on whole blood and serum samples collected before inoculation and at the end of Week 2/3.
Heat stress Aim 1: Using the X-ray structure of the heat shock protein A1A, the ATPase site and the allosteric pocket containing Cys306, which was recently identified as a druggable site, will be targeted. High-throughput virtual screening will be conducted on two libraries, an in-house collection of diverse small molecules (~155K compounds) at our Pharmacy Department and a ~500 million compound database of commercially available small molecules maintained by Molport. Each molecule will be scored and ranked, following which a top set of 200 chemically diverse compounds will be further inspected virtually for undesirable substructures and molecular properties. A final ~20 compounds will be purchased for wet lab cytotoxicity testing as we did for B7’s initial characterization. 4-5 compounds that are safe and specific for future effectiveness testing will be identified.