LvID-BDP: A Conotoxin-Based Fluorescent Probe for Visualizing α7 nAChR Expression in Intestinal Inflammation

The α7 nicotinic acetylcholine receptor (α7 nAChR) modulates neuroimmune signaling but remains poorly characterized in peripheral disease due to a lack of visualization tools. We developed the fluorescent probe LvID-BDP by conjugating a BODIPY fluorophore to the high-affinity α7 nAChR-targeting peptide LvID. LvID-BDP showed high quantum yield, robust photostability, and sufficient physiological stability for biological imaging. Electrophysiology characterized LvID-BDP as a potent α7 nAChR antagonist, exhibiting a half-maximal inhibitory concentration (IC₅₀) of 119.2 nM while retaining high affinity and specificity for the receptor. In murine colon sections, LvID-BDP specifically labeled α7 nAChR, showing strong antibody colocalization (Pearson's R = 0.87) while revealing macrophage-selective enrichment (Pearson's R = 0.85). This probe detected α7 nAChR alterations in engineered and inflamed macrophages and quantified its expression in inflammatory bowel disease (IBD) tissues. LvID-BDP provides a valuable pharmacological tool for specific α7 nAChR visualization in peripheral disease contexts, advancing pathological mechanism research.