Stabilization of desmoglein-2 binding rescues arrhythmia in arrhythmogenic cardiomyopathy
Camilla Schinner, … , Thomas D. Mueller, Jens Waschke
Camilla Schinner, … , Thomas D. Mueller, Jens Waschke
Published May 7, 2020
Citation Information: JCI Insight. 2020;5(9):e130141. https://doi.org/10.1172/jci.insight.130141.
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Research Article Cardiology

Stabilization of desmoglein-2 binding rescues arrhythmia in arrhythmogenic cardiomyopathy

Abstract

Arrhythmogenic cardiomyopathy (AC) is a genetic disease causing arrhythmia and sudden cardiac death with only symptomatic therapy available at present. Mutations of desmosomal proteins, including desmoglein-2 (Dsg2) and plakoglobin (Pg), are the major cause of AC and have been shown to lead to impaired gap junction function. Recent data indicated the involvement of anti-Dsg2 autoantibodies in AC pathogenesis. We applied a peptide to stabilize Dsg2 binding similar to a translational approach to pemphigus, which is caused by anti-desmoglein autoantibodies. We provide evidence that stabilization of Dsg2 binding by a linking peptide (Dsg2-LP) is efficient to rescue arrhythmia in an AC mouse model immediately upon perfusion. Dsg2-LP, designed to cross-link Dsg2 molecules in proximity to the known binding pocket, stabilized Dsg2-mediated interactions on the surface of living cardiomyocytes as revealed by atomic force microscopy and induced Dsg2 oligomerization. Moreover, Dsg2-LP rescued disrupted cohesion induced by siRNA-mediated Pg or Dsg2 depletion or l-tryptophan, which was applied to impair overall cadherin binding. Dsg2-LP rescued connexin-43 mislocalization and conduction irregularities in response to impaired cardiomyocyte cohesion. These results demonstrate that stabilization of Dsg2 binding by Dsg2-LP can serve as a novel approach to treat arrhythmia in patients with AC.

Authors

Camilla Schinner, Bernd Markus Erber, Sunil Yeruva, Angela Schlipp, Vera Rötzer, Ellen Kempf, Sebastian Kant, Rudolf E. Leube, Thomas D. Mueller, Jens Waschke

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Figure 4

Stabilization of Dsg2 binding rescues irregular conduction of excitation and arrhythmia caused by impaired desmosomes.

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Stabilization of Dsg2 binding rescues irregular conduction of excitation...
(A) Representative MEA heatmaps of transversal slices of WT and Pg-KO hearts treated with Dsg2-LP for 1 hour showing the delay of spontaneous excitations relative to a reference electrode (*). Colors correspond to the delay times of excitation given in the scale. Distance between neighboring electrodes: 200 μm. (B) Corresponding analysis of conduction velocity measured in cardiac slices as shown in A (WT control n = 9; WT Dsg2-LP n = 6 from 3 mice; Pg-KO control n = 11; Pg-KO Dsg2-LP n = 12 from 5 mice). Two-way ANOVA with Holm-Šidák post hoc test was performed. (C and F) MEA heatmaps from spontaneously contracting HL-1 cardiomyocytes treated with Dsg2-LP. Pg and Dsg2-levels were reduced by siRNA (Pg-siRNA, Dsg2-siRNA; n.t.-siRNA served as control). Distance between neighboring electrodes: 200 μm. (D, E, G, and H) Corresponding analysis of conduction velocity and SDNN of MEAs as described in C (control n = 5; Trp n = 5; Trp + Dsg2-LP n = 4; Dsg2-LP n = 5), and (F) (n.t.-siRNA n = 5; Pg-siRNA n = 4; Pg-siRNA + Dsg2-LP n = 3; Dsg2-siRNA n = 5; Dsg2-siRNA + Dsg2-LP n = 3). One-way ANOVA with Bonferroni’s post hoc test was performed. (I and J) Western blot analysis shows phosphorylation of Cx43 at serine 368 (pCx43 Ser368) in response to PKC activation by PMA and PKC inhibition by Bim-X or Dsg2-LP in HL-1 (I) and WT mice ventricular cardiac slices (J). Values in top row display mean of densitometric analysis ± SD. Total Cx43 was used as a reference protein. α-Tubulin (α-Tub) served as loading control (n = 4). (K–M) MEAs of Pg-reduced HL-1 cardiomyocytes treated with Bim-X and Dsg2-LP with corresponding analysis of conduction velocity and SDNN (n = 3). *P < 0.05. One-way ANOVA with Bonferroni’s post hoc test.