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 8

Base editing to correct DSP p.R1951X reduces inflammation in EHTs.

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Base editing to correct DSP p.R1951X reduces inflammation in EHTs. (A) S...
(A) Sanger sequencing of p.R1951X hiPSCs before and after base editing to correct the pathogenic DSP variant using gRNA8 and an adenine base editor (ABE). Base editing restored the reading frame, and the corrected line was termed p.R1951XCor. (B) Fractional shortening (FS) measurements of p.R1951X and p.R1951XCor EHTs showed improved contractility following genomic correction (****< 0.0001 by 2-tailed t test with Welch’s correction; n = 15 per condition). (C and D) Cytokine arrays of EHT media demonstrate significant reduction of cytokine secretion following genomic correction of DSP p.R1951X. Targets displayed in colored boxes are quantified in relation to Reference Dots (D) (†< 0.0001, ‡< 0.001, ◊< 0.05 by 2-way ANOVA with n = 4 per condition). Data presented as mean ± SEM.