Synthetic cannabinoid receptor agonists inhibit the cardiac voltage-gated potassium channel hERG

Figures

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  Fig. 1. The majority of tested SCRAs inhibit hERG. Chemical structure of the SCRAs JWH-018 (a) and Δ9-THC (b). c Schematic illustration of the division of a generic SCRA into four key building blocks: the head, linker, core, and tail. d CB1 receptor activation of JWH-018 (n = 3) and Δ9-THC (n = 3), where data are normalized to the maximal response of JWH-018 (used as reference), arbitrarily set at 100%. Chemical structures of the SCRAs 5F-MDMB-PINACA (e) and JWH-030 (f). g Schematic illustration of an action potential from a ventricular cardiomyocyte, with its five phases (0-4) indicated, where phase 3 represents the repolarization phase. The solid black line represents an action potential under normal conditions, the solid red line represents action potential prolongation due to compromised repolarization (e.g., reduced IKr or IKs). Representative effect of JWH-030 on hERG using the voltage protocol shown as inset (h), with corresponding G(V) curve (i). Concentration-response relationship for Gmax (rel) (j) or V50 (k) effect of JWH-030 and 5F-MDMB-PINACA. n = 6-8 for JWH-030; n = 4-17 for 5F-MDMB-PINACA. l, m Same as in (h, i) but for 5F-MDMB-PINACA. Average effect of 10 µM of the…

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  Fig. 2. Chemical modifications to the SCRA building blocks impact hERG effects. a Schematic illustration of the four key building blocks of SCRAs colour coded as in subsequent illustrations. b Schematic illustration of SCRAs with indole and indazole cores, together with comparison of effect at 10 µM. n = 4–9. c, d Example of impact of core moiety on hERG inhibition, illustrated by MDMB-CHMICA and MDMB-CHMINACA. n = 4–5. Additional examples are shown in Fig. S4. e Schematic illustration of SCRAs with indicated heads, together with a comparison of the effect at 10 µM. n = 4–7. f Example of the impact of the head moiety showcased by ADB-CHMINACA and AB-CHMINACA for hERG inhibition. n = 4. Additional examples are shown in Fig. S4. g Molecular structures of three SCRAs with 5F-PINACA scaffolds and variable head groups, and concentration-response relationships for indicated SCRAs on hERG inhibition. n = 4–17. h Molecular structures of two SCRAs with Cumyl-INACA scaffolds and variable tails, and concentration-response relationships for indicated SCRAs on hERG inhibition. n = 4–7. i Molecular structures of three SCRAs with BZO-OXIZID scaffolds and variable tails, and concentration-response…

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  Fig. 3. Accelerated weighted histogram simulations provide insight into SCRA binding poses. a Simplified schematic illustration of hERG (side view) indicating the central ion-conducting pathway delineated by the selectivity filter, S624 (denoted S), and Y652 (denoted Y) in the central cavity. Pore domain regions are in orange and the voltage-sensor S4 in teal. The central cavity site is indicated in dashed blue and the lateral side pocket site in dashed dark orange. b Structural representation of the path for astemizole (purple) to sample along the z-axis of hERG (orange) with respect to Y652 (green). c Electron density map obtained from EMD-60574 (cyan) overlayed on the cryo-EM structure of astemizole (purple), compared to the pose obtained from the minima by AWH (yellow). d Free energy landscape of the hERG inhibitor 5F-MDMB-PINACA sampling along the z-axis with respect to Y652, starting from the pose based on astemizole. A red circle and a cross mark the minima of the landscape. Different colours indicate different clusters extracted from DBSCAN with the epsilon = 0.2 with at least 10 frames in the cluster. e) Same as in d but for 5F-BZO-POXIZID. Snapshots of 5F-MDMB-PINACA (f) and…

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  Fig. 4. Comparison of SCRA features important for CB1 and hERG effects reveal similarities and differences. a Potency of the indicated SCRAs on CB1 (see methods for details). n ≥ 3 (except from JWH-030 where n = 2). (b-c) Example of impact of core moiety for CB1 activation showcased by MDMB-CHMICA and MDMB-CHMINACA (n = 3; structures in (b) and CB1 activating effects in (c). d Outcome of SAR analysis (paired t-test, α = 0.05) of SCRAs with indole and indazole cores (n = 4) for CB1 potency. e Schematic illustration of SCRAs with indicated heads, together with the outcome of SAR analysis (paired t-test, α = 0.05; n = 3, 3, and 5, respectively) for CB1 potency. f Molecular structures of two SCRAs with Cumyl-INACA scaffolds and variable tails, and concentration-response relationships for indicated SCRAs on CB1 activity (n = 4 for 5F-Cumyl-PINACA and n = 5 for Cumyl-TsINACA). g Outcome of SAR analysis of SCRAs with non-fluorinated compared with fluorinated pentyl tails for CB1 potency. h Comparison of Gmax response of hERG induced by SCRAs at 10 µM (y-axis) and CB1 potency (x-axis). Specific SCRAs are highlighted as indicated in the figure. All average data are shown as mean ± SEM. Small…

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  Fig. 5. Some tested SCRAs also inhibit KV7.1/KCNE1. a Chemical structure of MDMB-5’Br-BUTINACA. In b, representative effect of 10 µM MDMB-5’Br-BUTINACA on KV7.1/KCNE1 using the voltage protocol shown as inset with corresponding G(V) curve (c). d Concentration-response relationship for V50 effect of MDMB-5’Br-BUTINACA on KV7.1/KCNE1. n = 4–5. Average effect of 10 µM of the indicated SCRAs on V50 (e) and Gmax (f) of KV7.1/KCNE1. n = 4–9. Statistical comparisons were performed versus time-matched vehicle controls. For comparisons involving a single compound versus vehicle, Welch’s t-test was used. For comparisons involving multiple compounds sharing the same vehicle control, one-way ANOVA (no matching) followed by Dunnett’s multiple comparisons test was applied. Homogeneity of variance was assessed using the Brown–Forsythe test, and when significant heteroscedasticity was detected (P < 0.05), Welch’s ANOVA followed by Dunnett’s T3 multiple comparisons test was used instead. Statistics denote adjusted P-values for comparisons to vehicle: P < 0.05 (*), P < 0.01 (**), P < 0.001 (***), P < 0.0001 (****). Chemical structure of 5F-MDMB-PINACA (g) and JWH-030 (h) with concentration-response…