Adenylyl cyclase 5–generated cAMP controls cerebral vascular reactivity during diabetic hyperglycemia
Arsalan U. Syed, … , Madeline Nieves-Cintrón, Manuel F. Navedo
Arsalan U. Syed, … , Madeline Nieves-Cintrón, Manuel F. Navedo
Published June 4, 2019
Citation Information: J Clin Invest. 2019;129(8):3140-3152. https://doi.org/10.1172/JCI124705.
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Research Article Cell biology Vascular biology

Adenylyl cyclase 5–generated cAMP controls cerebral vascular reactivity during diabetic hyperglycemia

Abstract

Elevated blood glucose (hyperglycemia) is a hallmark metabolic abnormality in diabetes. Hyperglycemia is associated with protein kinase A–dependent (PKA-dependent) stimulation of L-type Ca2+ channels in arterial myocytes resulting in increased vasoconstriction. However, the mechanisms by which glucose activates PKA remain unclear. Here, we showed that elevating extracellular glucose stimulates cAMP production in arterial myocytes, and that this was specifically dependent on adenylyl cyclase 5 (AC5) activity. Super-resolution imaging suggested nanometer proximity between subpopulations of AC5 and the L-type Ca2+ channel pore-forming subunit CaV1.2. In vitro, in silico, ex vivo, and in vivo experiments revealed that this close association is critical for stimulation of L-type Ca2+ channels in arterial myocytes and increased myogenic tone upon acute hyperglycemia. This pathway supported the increase in L-type Ca2+ channel activity and myogenic tone in 2 animal models of diabetes. Our collective findings demonstrate a unique role for AC5 in PKA-dependent modulation of L-type Ca2+ channel activity and vascular reactivity during acute hyperglycemia and diabetes.

Authors

Arsalan U. Syed, Gopireddy R. Reddy, Debapriya Ghosh, Maria Paz Prada, Matthew A. Nystoriak, Stefano Morotti, Eleonora Grandi, Padmini Sirish, Nipavan Chiamvimonvat, Johannes W. Hell, Luis F. Santana, Yang K. Xiang, Madeline Nieves-Cintrón, Manuel F. Navedo

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Figure 3

AC5 is necessary for cAMP synthesis, L-type Ca2+ channel potentiation, and vasoconstriction in response to elevated glucose.

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AC5 is necessary for cAMP synthesis, L-type Ca2+ channel potentiation, a...
(A) Averaged ICUE3-PM responses to 20 mM d-glucose before and after forskolin (1 μM) in WT, AC5–/–, and AC5–/+ cells. Experiments from at least 3 different isolations, with 3 mice per isolation. (B) Plot of maximum FRET response to 20 mM d-glucose and 20 mM d-glucose + 1 μM forskolin in WT (n = 92), AC5–/– (n = 114), and AC5–/+ (n = 40) cells. *P < 0.05, Kruskal-Wallis test. Significance was compared between the 20 mM d-glucose and forskolin response and the 20 mM d-glucose response for all conditions. (C) Nifedipine-sensitive IBa-voltage relationship in WT (n = 6 cells) and AC5–/– (n = 8 cells) cells in 10 mM and 20 mM d-glucose. *P < 0.05, Wilcoxon matched-pairs signed-rank test. Cell capacitance was similar for WT (17.0 ± 0.8 pF) and AC5–/– cells (19.3 ± 1.9 pF; P = 0.4700, Mann-Whitney test). (D) Normalized in silico (sim, light gray and light blue lines) and exemplary experimental (exp, black and blue lines) [Ca2+]i traces from arterial myocytes in intact WT and AC5–/– arteries in response to 20 mM d-glucose, and plot of the percentage change in Ca2+ in response to 20 mM d-glucose in WT (from 7 arteries) and AC5–/– (from 9 arteries) cells (*P < 0.05, Mann-Whitney test). (E and F) Representative diameter recordings (E) and summary changes in arterial tone (F) from WT (n = 7 arteries from 4 mice), AC5–/– (n = 7 arteries from 4 mice), and AC5–/+ (n = 9 arteries from 4 mice) pressurized arteries in response to 20 mM d-glucose. *P < 0.05, Kruskal-Wallis with Dunn’s multiple comparisons. Data represent mean ± SEM.