Peripherally restricted PICK1 inhibitor mPD5 ameliorates pain behaviors in murine inflammatory and neuropathic pain models
Kathrine Louise Jensen, … , Andreas Toft Sørensen, Kenneth Lindegaard Madsen
Kathrine Louise Jensen, … , Andreas Toft Sørensen, Kenneth Lindegaard Madsen
Published September 17, 2024
Citation Information: JCI Insight. 2024;9(20):e170976. https://doi.org/10.1172/jci.insight.170976.
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Research Article Neuroscience

Peripherally restricted PICK1 inhibitor mPD5 ameliorates pain behaviors in murine inflammatory and neuropathic pain models

Abstract

Chronic pain is a complex, debilitating, and escalating health problem worldwide, impacting 1 in 5 adults. Current treatment is compromised by dose-limiting side effects, including high abuse liability, loss of ability to function socially and professionally, fatigue, drowsiness, and apathy. PICK1 has emerged as a promising target for the treatment of chronic pain conditions. Here, we developed and characterized a cell-permeable fatty acid–conjugated bivalent peptide inhibitor of PICK1 and assessed its effects on acute and chronic pain. The myristoylated PICK1 inhibitor, myr-NPEG4-(HWLKV)2 (mPD5), self-assembled into core-shell micelles that provided favorable pharmacodynamic properties and relieved evoked mechanical and thermal hypersensitivity as well as ongoing hypersensitivity and anxiodepressive symptoms in mouse models of neuropathic and inflammatory pain following subcutaneous administration. No overt side effects were associated with mPD5 administration, and it had no effect on acute nociception. Finally, neuropathic pain was relieved far into the chronic phase (18 weeks after spared nerve injury surgery) and while the effect of a single injection ceased after a few hours, repeated administration provided pain relief lasting up to 20 hours after the last injection.

Authors

Kathrine Louise Jensen, Nikolaj Riis Christensen, Carolyn Marie Goddard, Sara Elgaard Jager, Gith Noes-Holt, Ida Buur Kanneworff, Alexander Jakobsen, Lucía Jiménez-Fernández, Emily G. Peck, Line Sivertsen, Raquel Comaposada Baro, Grace Anne Houser, Felix Paul Mayer, Marta Diaz-delCastillo, Marie Løth Topp, Chelsea Hopkins, Cecilie Dubgaard Thomsen, Ahmed Barakat Ibrahim Soltan, Frederik Grønbæk Tidemand, Lise Arleth, Anne-Marie Heegaard, Andreas Toft Sørensen, Kenneth Lindegaard Madsen

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Figure 1

Biophysical characterization of mPD5.

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Biophysical characterization of mPD5. Structure of NPEG4-(HWLKV)2 (PD5) ...
Structure of NPEG4-(HWLKV)2 (PD5) (A) and myristoyl-NPEG4-(HWLKV)2 (mPD5) (B) (hydrophobic parts in blue). (C) Size exclusion chromatography (SEC) with different concentrations of mPD5 demonstrating self-assembly. (D) Small-angle x-ray scattering (SAXS) data (points) of mPD5 at different concentrations. Model fits of the core-shell model (lines) (see Supplemental Table 1 for fitting parameters). l(q) = scattering intensity. (E) Molecularly constrained spherical core-shell model fitted to the data in Supplemental Figure 1B reveals 20.5 molecules/micelle: total radius, Rtotal = 22.6 Å. (F–H) Experimental illustration above data. (F) Flow-induced dispersion analysis (FIDA) binding isotherm of mPD5 combining optimal coatings for different concentrations (additional information in Supplemental Figure 2); CMC = 12 μM; hydrodynamic radius, RH ≈ 30 Å. (G) Fluorescence polarization (FP) competition binding curves of mPD5 (blue) (Ki,app = 3.0 nM, SEM interval [2.3–3.8] nM, n = 6), TPD5 (purple) (Ki,app = 3.9 nM, SEM interval [3.5–4.4] nM, n = 3) and D5 (HWLKV) (green) (Ki,app = 6998 nM, SEM interval [4972–9849] nM, n = 3), using 5FAM-PD5 (5 nM vs. TPD5 and mPD5) or 5FAM-D5 (20 nM vs. D5) as tracer. Data were fitted to a competitive binding 1-site fit using GraphPad Prism 8.3. (H) SEC elution profile of PICK1 in the absence (purple) or presence (blue) of mPD5, at a PICK1/mPD5 molecular ratio of 4:1. (I) Isotherm of mPD5-AF488 binding to human serum albumin (HSA); affinity (KD) = 787 nM; hydrodynamic radius (RH) of the complex = 4.46 nm. Experimental illustration is to the left of the data. (J) Histogram showing the RHs ± SEM of mPD5 (n = 3).