Kalita, M. et al. (2023) PET imaging of innate immune activation using 11C radiotracers targeting GPR84. JACS Au, 3(12), pp. 3297-3310. (doi: 10.1021/jacsau.3c00435) (PMID:38155640) (PMCID:PMC10751761)
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Abstract
Chronic innate immune activation is a key hallmark of many neurological diseases and is known to result in the upregulation of GPR84 in myeloid cells (macrophages, microglia, and monocytes). As such, GPR84 can potentially serve as a sensor of proinflammatory innate immune responses. To assess the utility of GPR84 as an imaging biomarker, we synthesized 11C-MGX-10S and 11C-MGX-11Svia carbon-11 alkylation for use as positron emission tomography (PET) tracers targeting this receptor. In vitro experiments demonstrated significantly higher binding of both radiotracers to hGPR84-HEK293 cells than that of parental control HEK293 cells. Co-incubation with the GPR84 antagonist GLPG1205 reduced the binding of both radiotracers by >90%, demonstrating their high specificity for GPR84 in vitro. In vivo assessment of each radiotracer via PET imaging of healthy mice illustrated the superior brain uptake and pharmacokinetics of 11C-MGX-10S compared to 11C-MGX-11S. Subsequent use of 11C-MGX-10S to image a well-established mouse model of systemic and neuro-inflammation revealed a high PET signal in affected tissues, including the brain, liver, lung, and spleen. In vivo specificity of 11C-MGX-10S for GPR84 was confirmed by the administration of GLPG1205 followed by radiotracer injection. When compared with 11C-DPA-713-an existing radiotracer used to image innate immune activation in clinical research studies-11C-MGX-10S has multiple advantages, including its higher binding signal in inflamed tissues in the CNS and periphery and low background signal in healthy saline-treated subjects. The pronounced uptake of 11C-MGX-10S during inflammation, its high specificity for GPR84, and suitable pharmacokinetics strongly support further investigation of 11C-MGX-10S for imaging GPR84-positive myeloid cells associated with innate immune activation in animal models of inflammatory diseases and human neuropathology.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Milligan, Professor Graeme and Marsango, Dr Sara |
| Creator Roles: | |
| Authors: | Kalita, M., Park, J. H., Kuo, R. C., Hayee, S., Marsango, S., Straniero, V., Alam, I. S., Rivera-Rodriguez, A., Pandrala, M., Carlson, M. L., Reyes, S. T., Jackson, I. M., Suigo, L., Luo, A., Nagy, S. C., Valoti, E., Milligan, G., Habte, F., Shen, B., and James, M. L. |
| College/School: | College of Medical Veterinary and Life Sciences > School of Molecular Biosciences |
| Journal Name: | JACS Au |
| ISSN: | 2691-3704 |
| ISSN (Online): | 2691-3704 |
| Copyright Holders: | Copyright © 2023 The American Chemical Society |
| First Published: | First published in JACS Au 3:(12)3297–3310 |
| Publisher Policy: | Reproduced under a Creative Commons licence |
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