Susceptibility to innate immune activation in genetically mediated myocarditis
Daniel F. Selgrade, … , Kathleen J. Green, Elizabeth M. McNally
Daniel F. Selgrade, … , Kathleen J. Green, Elizabeth M. McNally
Published May 20, 2024
Citation Information: J Clin Invest. 2024;134(13):e180254. https://doi.org/10.1172/JCI180254.
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Research Article Cardiology Inflammation

Susceptibility to innate immune activation in genetically mediated myocarditis

Abstract

Myocarditis is clinically characterized by chest pain, arrhythmias, and heart failure, and treatment is often supportive. Mutations in DSP, a gene encoding the desmosomal protein desmoplakin, have been increasingly implicated in myocarditis. To model DSP-associated myocarditis and assess the role of innate immunity, we generated engineered heart tissues (EHTs) using human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) from patients with heterozygous DSP truncating variants (DSPtvs) and a gene-edited homozygous deletion cell line (DSP–/–). At baseline, DSP–/– EHTs displayed a transcriptomic signature of innate immune activation, which was mirrored by cytokine release. Importantly, DSP–/– EHTs were hypersensitive to Toll-like receptor (TLR) stimulation, demonstrating more contractile dysfunction compared with isogenic controls. Relative to DSP–/– EHTs, heterozygous DSPtv EHTs had less functional impairment. DSPtv EHTs displayed heightened sensitivity to TLR stimulation, and when subjected to strain, DSPtv EHTs developed functional deficits, indicating reduced contractile reserve compared with healthy controls. Colchicine or NF-κB inhibitors improved strain-induced force deficits in DSPtv EHTs. Genomic correction of DSP p.R1951X using adenine base editing reduced inflammatory biomarker release from EHTs. Thus, EHTs replicate electrical and contractile phenotypes seen in human myocarditis, implicating cytokine release as a key part of the myogenic susceptibility to inflammation. The heightened innate immune activation and sensitivity are targets for clinical intervention.

Authors

Daniel F. Selgrade, Dominic E. Fullenkamp, Ivana A. Chychula, Binjie Li, Lisa Dellefave-Castillo, Adi D. Dubash, Joyce Ohiri, Tanner O. Monroe, Malorie Blancard, Garima Tomar, Cory Holgren, Paul W. Burridge, Alfred L. George Jr., Alexis R. Demonbreun, Megan J. Puckelwartz, Sharon A. George, Igor R. Efimov, Kathleen J. Green, Elizabeth M. McNally

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Figure 7

Improved mechanical function with colchicine treatment of DSPtv EHTs.

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Improved mechanical function with colchicine treatment of DSPtv EHTs. (A...
(A) Representative force from DSP p.R1951X EHTs subjected to 10% strain with and without colchicine. Exposure to 10% strain produced marked mechanical alternans (marked with asterisks), which was corrected with colchicine treatment. (B and C) Colchicine significantly improved relative mechanical force production in DSP p.R1951X EHTs at baseline conditions and after isometric strain (*< 0.05, **< 0.01, ****< 0.0001 by 2-way ANOVA, n = 3–4 EHTs per condition, labeled as n1 = black dots, n2 = white dots, n3 = gray dots, n4 = brown dots). Box plots show the interquartile range, median (line), and minimum and maximum (whiskers). (D) DSP p.E1597X EHTs also showed marked alternans (marked with asterisks) after 10% strain, which was improved by colchicine. (E and F) Colchicine improved relative force in DSP p.E1597X EHTs at baseline and with 5% or 10% strain (*< 0.05, **< 0.01, ***< 0.001 by 2-way ANOVA, n = 3–4 EHTs per condition, labeled as n1 = black dots, n2 = white dots, n3 = gray dots, n4 = brown dots). (G and H) Cytokine arrays from p.E1597X EHT media showed a significant reduction of baseline cytokine secretion following colchicine treatment (†< 0.0001, ‡< 0.001, Δ< 0.01, ◊< 0.05 by 2-way ANOVA with n = 4 per condition). (I) Fractional shortening of DSP p.E1597X and p.R1951X EHTs treated with 5 μM colchicine for 48 hours demonstrated improved contractility compared with vehicle control (****< 0.0001 by 2-way ANOVA, n = 9–12 EHTs per condition). Data presented as individual recordings normalized to average baseline measurement per EHT. Significance calculated based on mean value per EHT.