Targeting the neuropilin-1 receptor (NRP-1)/VEGF-A axis for neuropathic pain

NIH RePORTER · NIH · R41 · $419,470 · view on reporter.nih.gov ↗

Abstract

ABSTRACT Revisions noted in blue font First reported in December of 2019, coronavirus disease (COVID-19) has taken the world by storm, exacting a heavy toll not only in terms of the number of deaths (~1,700,000) it has caused worldwide but also its decimation of world economies (~$8.8 trillion). Because infection with SARS-CoV-2, the causative agent of COVD-19, can be spread by asymptomatic, presymptomatic, and symptomatic carriers, the virus has been difficult to contain. Our preliminary data shows that Spike protein, the major surface antigen of SARS-CoV-2, is analgesic. Therefore, an explanation for the unabated spread (~77 million infected worldwide as of December 21, 2020) may be that asymptomatic or presymptomatic individuals do not experience the pain and discomfort that act as early warning signs of infection. We found that Spike protein binds to a surface receptor called neuropilin 1 (NRP- 1) to allow viral entry into cells. Vascular endothelial growth factor-A (VEGF-A) – a pro-nociceptive and angiogenic factor, binds NRP-1, and induces mechanical allodynia and thermal hyperalgesia that is blocked by Spike protein. Pharmacological antagonism of NRP-1 also blocks VEGF-A–induced pain behaviors. These results identify NRP-1 as a new player in pain. How VEGF-A–activated signaling via NRP-1 leads to pain is an open question. Leveraging this atypical pain-relieving function of the SARS-CoV-2 Spike interaction with NRP- 1, the laboratory of Dr. Rajesh Khanna (University of Arizona (UA)) performed a virtual screen of nearly 0.5 million compounds (diverse small molecules and commercially available natural products) against the VEGF-A binding site on the NRP-1 b1 domain. Several of the top 20 ‘hit’ compounds from this screen have been validated in in vitro and in vivo experiments, providing experimental proof of our in-silico predictions. We have partnered with Regulonix LLC to test the hypothesis that SARS-CoV-2 Spike protein binding to NRP-1 triggers increases in sodium and calcium channel activity to increase nociceptor activity culminating in enhanced pain and that this signaling cascade can be blocked by inhibitors of NRP-1-VEGF-A interaction. Regulonix’s Specific Aims, guided by quantitative goals, are: (1) to profile NRP-1 targeting compounds for their (i) to ability to bind to NRP- 1; (ii) to block the NRP-1-VEGF-A interaction using ELISA; and (iii) to inhibit VEGF-A mediated increase in phosphorylation of VEGFR2, a proxy for activation of VEGF-A/NRP-1 signaling. A subset of compounds will be tested for their ability to inhibit calcium and sodium currents in sensory neurons using whole-cell electrophysiology with a smaller subset being tested in human DRGs to enhance rigor and the translational utility of these compounds; (2) Profile NRP-1 targeting compounds for their in vitro cellular cytotoxicity, physico- chemical, early ADME, and PK properties, and for off-target effects on GPCRs, kinases, ion channels and alternative known pain targe...

Key facts

NIH application ID
10321851
Project number
1R41NS122545-01A1
Recipient
REGULONIX, LLC
Principal Investigator
Rajesh Khanna
Activity code
R41
Funding institute
NIH
Fiscal year
2021
Award amount
$419,470
Award type
1
Project period
2021-09-01 → 2023-08-31