Department of Surgery, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
Department of Surgery, Morsani College of Medicine, University of South Florida, Tampa, FL, USA; Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.
Pharmacol Res. 2023 Apr;190:106730. doi: 10.1016/j.phrs.2023.106730. Epub 2023 Mar 15.
We reported previously that α-adrenoceptor (α-AR) ligands inhibit chemokine receptor (CR) heteromerization partners of α-AR. The underlying mechanisms are unknown and in vivo evidence for such effects is missing. Utilizing CCR2 and α-AR as prototypical partners, we observed in recombinant systems and THP-1 cells that α-AR enhanced whereas its absence inhibited Gαi signaling of CCR2. Phenylephrine and phentolamine reduced the CCR2:α-AR heteromerization propensity and inhibited Gαi signaling of CCR2. Phenylephrine cross-recruited β-arrestin-2 to CCR2, and reduced expression of α-AR, CR partners (CCR1/2, CXCR4) and corresponding heteromers. Phentolamine reduced CR:α-AR heteromers without affecting β-arrestin-2 recruitment or receptor expression. Phenylephrine/phentolamine prevented leukocyte infiltration mediated via CR heteromerization partners in a murine air pouch model. Our findings document that α-AR ligands inhibit leukocyte migration mediated by CR heteromerization partners in vivo and suggest interference with α-AR:CR heteromerization as a mechanism by which CR partners are inhibited. These findings provide new insights into the pharmacology of GPCR heteromers and indicate that an agonist and antagonist at one GPCR can act as antagonists at heteromerization partners of their target receptors.
我们之前曾报道过，α-肾上腺素受体 (α-AR) 配体抑制趋化因子受体 (CR) 作为 α-AR 的异源三聚体伙伴。其潜在机制尚不清楚，也缺乏体内相关证据。利用 CCR2 和 α-AR 作为典型的伙伴，我们在重组系统和 THP-1 细胞中观察到，α-AR 增强了 CCR2 的 Gαi 信号，而其缺失则抑制了 CCR2 的 Gαi 信号。苯肾上腺素和酚妥拉明降低了 CCR2:α-AR 异源三聚体形成的倾向，并抑制了 CCR2 的 Gαi 信号。苯肾上腺素将β-arrestin-2 募集到 CCR2 上，并降低了 α-AR、CR 伙伴（CCR1/2、CXCR4）和相应异源三聚体的表达。酚妥拉明降低了 CR:α-AR 异源三聚体，而不影响β-arrestin-2 的募集或受体表达。苯肾上腺素/酚妥拉明在小鼠气囊模型中预防了通过 CR 异源三聚体伙伴介导的白细胞浸润。我们的研究结果证明了 α-AR 配体在体内抑制了由 CR 异源三聚体伙伴介导的白细胞迁移，并提示干扰 α-AR:CR 异源三聚体形成可能是抑制 CR 伙伴的一种机制。这些发现为 GPCR 异源三聚体的药理学提供了新的见解，并表明一个 GPCR 的激动剂和拮抗剂可以作为其靶受体的异源三聚体伙伴的拮抗剂。
