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bioRxiv · 10.1101/2021.06.21.449162

Chimeric GPCRs mimic distinct signaling pathways and modulate microglia responses

Schulz, R.·Korkut-Demirbas, M.·Colombo, G.·Siegert, S.
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Abstract

G protein-coupled receptors (GPCRs) regulate multiple processes ranging from cell growth and immune responses to neuronal signal transmission. However, ligands for many GPCRs remain unknown, suffer from off-target effects or have poor bioavailability. Additional challenges exist to dissect cell type-specific responses when the same GPCR is expressed on different cells within the body. Here, we overcome these limitations by engineering DREADD-based GPCR chimeras that selectively bind their agonist clozapine-N-oxide (CNO) and mimic a GPCR-of-interest. We show that the chimeric DREADD-{beta}2-adrenergic receptor ({beta}2AR/ADRB2) triggers comparable responses to levalbuterol on second messenger and kinase activity, post-translational modifications, and protein-protein interactions. Moreover, we successfully recapitulate {beta}2AR-mediated filopodia formation in microglia, a {beta}2AR-expressing immune cell that can drive inflammation in the nervous system. To further dissect microglial inflammation, we compared DREADD-{beta}2AR with two additionally designed DREADD-based chimeras mimicking GPR65 and GPR109A/HCAR2, both enriched in microglia. DREADD-{beta}2AR and DREADD-GPR65 modulate the inflammatory response with a similar profile as endogenously expressed {beta}2AR, while DREADD-GPR109A had no impact. Our DREADD-based approach allows investigation of cell type-dependent signaling pathways and function without known endogenous ligands.

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Schulz, R., Korkut-Demirbas, M., Colombo, G., Siegert, S.. 2021-06-21. Chimeric GPCRs mimic distinct signaling pathways and modulate microglia responses. https://doi.org/10.1101/2021.06.21.449162

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