TY - JOUR
T1 - On the G protein-coupling selectivity of the native A2B adenosine receptor
AU - Gao, Zhan Guo
AU - Inoue, Asuka
AU - Jacobson, Kenneth A.
N1 - Funding Information:
Supported the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases (ZIADK031117), National Institutes of Health, Bethesda, MD, USA. AI was funded by the PRIME from Japan Agency for Medical Research and Development (AMED) and Japan Society for the Promotion of Science KAKENHI Grant Number 17 K08264. The authors thank Jurgen Wess (NIDDK, NIH) for advice, Ad IJzerman (Leiden, The Netherlands) for providing BAY60-6583 (LUF6210), E. Kiselev (NIDDK, NIH) for providing MRS5911, and H. Adachi (NIDDK, NIH) for MRS3997.
Funding Information:
Supported the Intramural Research Program of the National Institute of Diabetes and Digestive and Kidney Diseases (ZIADK031117), National Institutes of Health, Bethesda, MD, USA. AI was funded by the PRIME from Japan Agency for Medical Research and Development (AMED) and Japan Society for the Promotion of Science KAKENHI Grant Number 17 K08264. The authors thank Jurgen Wess ( NIDDK , NIH ) for advice, Ad IJzerman (Leiden, The Netherlands) for providing BAY60-6583 (LUF6210), E. Kiselev (NIDDK, NIH) for providing MRS5911, and H. Adachi (NIDDK, NIH) for MRS3997.
Publisher Copyright:
© 2017
PY - 2018/5
Y1 - 2018/5
N2 - A2B adenosine receptor (A2BAR) activation induces Gs-dependent cyclic AMP accumulation. However, A2BAR G protein-coupling to other signaling events, e.g. ERK1/2 and calcium, is not well documented. We explored Gi, Gq/11 and Gs coupling in 1321 N1 astrocytoma, HEK293, and T24 bladder cancer cells endogenously expressing human A2BAR, using NECA or nonnucleoside BAY60-6583 as agonist, selective Gi, Gs and Gq/11 blockers, and CRISPR/Cas9-based Gq- and Gs-null HEK293 cells. In HEK293 cells, A2BAR-mediated ERK1/2 activity occurred via both Gi and Gs, but not Gq/11. However, HEK293 cell calcium mobilization was completely blocked by Gq/11 inhibitor UBO-QIC and by Gq/11 knockout. In T24 cells, Gi was solely responsible for A2BAR-mediated ERK1/2 stimulation, and Gs suppressed ERK1/2 activity. A2BAR-mediated intracellular calcium mobilization in T24 cells was mainly via Gi, although Gs may also play a role, but Gq/11 is not involved. In 1321 N1 astrocytoma cells A2BAR activation suppressed rather than stimulated ERK1/2 activity. The ERK1/2 activity decrease was reversed by Gs downregulation using cholera toxin, but potentiated by Gi inhibitor pertussis toxin, and UBO-QIC had no effect. EPACs played an important role in A2BAR-mediated ERK1/2 signaling in all three cells. Thus, A2BAR may: couple to the same downstream pathway via different G proteins in different cell types; activate different downstream events via different G proteins in the same cell type; activate Gi and Gs, which have opposing or synergistic roles in different cell types/signaling pathways. The findings, relevant to drug discovery, address some reported controversial roles of A2BAR and could apply to signaling mechanisms in other GPCRs.
AB - A2B adenosine receptor (A2BAR) activation induces Gs-dependent cyclic AMP accumulation. However, A2BAR G protein-coupling to other signaling events, e.g. ERK1/2 and calcium, is not well documented. We explored Gi, Gq/11 and Gs coupling in 1321 N1 astrocytoma, HEK293, and T24 bladder cancer cells endogenously expressing human A2BAR, using NECA or nonnucleoside BAY60-6583 as agonist, selective Gi, Gs and Gq/11 blockers, and CRISPR/Cas9-based Gq- and Gs-null HEK293 cells. In HEK293 cells, A2BAR-mediated ERK1/2 activity occurred via both Gi and Gs, but not Gq/11. However, HEK293 cell calcium mobilization was completely blocked by Gq/11 inhibitor UBO-QIC and by Gq/11 knockout. In T24 cells, Gi was solely responsible for A2BAR-mediated ERK1/2 stimulation, and Gs suppressed ERK1/2 activity. A2BAR-mediated intracellular calcium mobilization in T24 cells was mainly via Gi, although Gs may also play a role, but Gq/11 is not involved. In 1321 N1 astrocytoma cells A2BAR activation suppressed rather than stimulated ERK1/2 activity. The ERK1/2 activity decrease was reversed by Gs downregulation using cholera toxin, but potentiated by Gi inhibitor pertussis toxin, and UBO-QIC had no effect. EPACs played an important role in A2BAR-mediated ERK1/2 signaling in all three cells. Thus, A2BAR may: couple to the same downstream pathway via different G proteins in different cell types; activate different downstream events via different G proteins in the same cell type; activate Gi and Gs, which have opposing or synergistic roles in different cell types/signaling pathways. The findings, relevant to drug discovery, address some reported controversial roles of A2BAR and could apply to signaling mechanisms in other GPCRs.
KW - A2B adenosine receptor
KW - Adenosine receptor
KW - Calcium
KW - ERK1/2
KW - G protein
KW - GPCR
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U2 - 10.1016/j.bcp.2017.12.003
DO - 10.1016/j.bcp.2017.12.003
M3 - Article
C2 - 29225130
AN - SCOPUS:85039415334
VL - 151
SP - 201
EP - 213
JO - Biochemical Pharmacology
JF - Biochemical Pharmacology
SN - 0006-2952
ER -