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 5

Close association between L-type Ca2+ channel CaV1.2 and AC5 in arterial myocytes.

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Close association between L-type Ca2+ channel CaV1.2 and AC5 in arterial...
(A) Exemplary TIRF images (top panels) and corresponding GSD reconstruction maps (middle panels) from a WT arterial myocyte labeled for CaV1.2 and AC5 (scale bar: 1 μm). Higher magnifications of the areas in the yellow boxes are shown in the bottom panels (scale bar: 200 nm). (B) Histograms of the area of clusters of CaV1.2 and AC5 in arterial myocytes (n = 7 cells). (C) Plot of the cluster density of CaV1.2 and AC5 in arterial myocytes (n = 7 cells). (D) Higher magnification of a merged image and associated x – y fluorescence intensity profile of areas of close association between CaV1.2 (green) and AC5 (red) (scale bar: 100 nm). (E) Histogram of the lowest intermolecular distance to AC5 centroids for CaV1.2 particles. Data were fit with a multi-Gaussian function (n = 30,141 particles from 7 cells). (F and G) Exemplary differential interference contrast (right panels) and confocal PLA/DAPI images (left panels) (scale bars: 10 μm) of arterial myocytes colabeled for CaV1.2 and AC5 (F) and CaV1.2 and AC6 (G). (H) Quantification of PLA puncta per square micrometer cell area for isolated arterial myocytes labeled with CaV1.2 (n = 21 cells), AC5 (n = 18 cells), AC6 (n = 22 cells), CaV1.2 + AC5 (n = 36 cells), or CaV1.2 + AC6 (n = 21 cells). *P < 0.05, Kruskal-Wallis with Dunn’s multiple comparisons. Significance was compared between data sets as specified. Data represent mean SEM.