Tuesday, April 30, 2024
4/30/2024
Mechanism of dual NaV1.7 and NaV1.8 block by a NaV inhibitory peptide aptamer Summary/Abstract: Multiple sensory neuronal sodium channels (NaVs) contribute to pain pathogenesis, indicating that development of a strategy for specific block of multiple NaVs in the pathological sensory neurons would be more effective for inhibiting pain signals than inhibiting only single NaV subtype. We discovered a polyacidic peptide from NaV1.7 intracellular segment and voltage-clamp recording shows that this peptide potently inhibits sodium currents conducted by both NaV1.7 and NaV1.8 (NaV1.7/1.8) channels. This dual NaV1.7/1.8 inhibitory peptide aptamer (named 1.7/1.8iPA, 38mer) contains a conserved Ankyrin (AnkG) binding domain and a multi-PDZ-domain protein class I binding domain (Pdzd2-I) between NaV1.7 and NaV1.8, suggesting that either AnkG or Pdzd2-I domain or both within 1.7/1.8iPA may contribute to its dual NaV1.7/1.8 inhibition. The overall goal of this proposal is to investigate 1) whether AnkG and/or Pdzd2-I domains in 1.7/1.8iPA is responsible for its dual NaV1.7/1.8 inhibition, and 2) whether expression of sequence defined 1.7/1.8iPA in the primary sensory neurons (PSN) will suppress PSN excitability, supporting 1.7/1.8iPA as a potential analgesic lead. Two specific aims will be investigated to test the hypothesis that 1.7/1.8iPA elicits dual block of NaV1.7/1.8 currents via a combined effects of AnkG and Pdzd2-I domains, leading to suppression of PSN action potential firing. Specific aim 1 will investigate and determine ion channel selectivity of 1.7/1.8iPA by in vitro of cell-based voltage-clamp recordings using HEK cells stably expressing various NaV subtypes and NG108-15 neuronal cells that naturally express potassium channels KV7.2/7.3 (both containing conserved AnkG binding domain). Specific aim 2 will determine electrogenesis and biological activity (neurotoxicity and animal behaviors) of 1.7/1.8iPA expression in the rat PSNs. Successful completion of this application will provide sufficient data to determine whether 1.7/1.8iPA is a potential analgesic lead to be further developed for AAV- mediated, PSN-specific dual NaV1.7/1.8 inhibition to treat chronic pain.
HHS’ Tracking Accountability in Government Grants System (TAGGS) website provides access to detailed descriptions of grants, loans, aggregated direct payments and other types of financial assistance awarded by the HHS Operating Divisions (OPDIVs) and the Office of the Secretary Staff Divisions (STAFFDIVs).
