Molecular Mechanisms of Antagonist Selectivity Against CCR2 and CCR5

• DOI: 10.1124/jpet.569.131403
• Publication Date: 2024-05-13T23:01:32Z
• Authors: Grant Wadman; Irina Kufareva; John Dawson; Penglie Zhang; Andrew Tebben; Percy Carter; Siyi Gu; Thomas Shroka; Leire Borrega-Roman; Catherina Salanga; Tracy Handel
• Keywords: CCR2; CCR5 receptor antagonist

<b>Abstract ID 131403</b> <b>Poster Board 569</b> Chemokine receptors 2 and 5 (CCR2 CCR5, respectively) are highly homologous G-protein coupled on the surface of select immune cells with distinct functions endogenous agonists but shared antagonists. These chemokine promising targets for small molecule therapeutics in treatment various cancers autoimmune diseases, despite only one currently approved therapeutic CCR5. Rational design future relies a structural understanding determinants antagonist selectivity as high affinity targeting receptor is often desired. Further complicating development, antagonists human CCR2 (hCCR2) inactive to mouse (mCCR2). Here, through rationally-guided gain-of-function mutagenesis, we characterized molecular CCR2/CCR5 human/mouse selectivity. Binding poses panel selective dual-specific were generated docking. Using these poses, hypothesized that single bulky residue TM2 hCCR5 (Y892.63) mCCR2 (Y1142.63) dictates by obstructing binding minor pocket-targeting orthosteric large substituents. By contrast, corresponding S1012.63 hCCR2 permissive such because it allows them occupy space otherwise filled tyrosine. To validate this hypothesis, introduced Y892.63S mutation into CCR5 tested ability previously CCR2-selective <b>cherney08a_22</b> inhibit chemokine-induced suppression forskolin-stimulated cAMP HeLa expressing mutant. Intracellular levels measured BRET-based CAMYEL reporter. experiments confirmed indeed CCR5(Y892.63S) mutant became sensitive <b>cherney08a_22</b>. We also demonstrated how same could impart against medium-size (acetamide) substituent. An alternative hypothesis was assessed predicted bind towards TM5 major pocket. Selectivity suspected be conveyed residues F1093.33, S18045.52, or I1985.42 which from their counterparts. However, introduction CCR2-mimicking F1093.33H S18045.52P mutations not sufficient produce sensitivity <b>PF-4136309</b>. therefore concluded its mechanism due R2065.42 hCCR5. Our findings provide better framework rational development dual-affinity overcome past deficiencies potent inhibitors.