Istaroxime treatment ameliorates calcium dysregulation in a zebrafish model of phospholamban R14del cardiomyopathy

Kamel, Sarah M.; Opbergen, Chantal J.M. van; Koopman, Charlotte D.; Verkerk, Arie O.; Boukens, Bastiaan J.; Jonge, Berend de; Onderwater, Y. L.; Alebeek, E. van; Chocron, Sonja; Pontalti, C. Polidoro; Weuring, Wout J.; Vos, MA; Boer, Teun P. de; Veen, Toon A.B. van; Bakkers, Jeroen

doi:10.1038/s41467-021-27461-8

Cited by 25 publications

(24 citation statements)

References 66 publications

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“…Based on initial findings from PLN-R14del overexpression in a heterologous cell culture system as well as in the mouse heart, PLN-R14del was proposed to exert super-inhibitory effects on SERCA2a activity, leading to cardiac remodeling and early death [5]. Additional evidence has recently emerged from numerous studies on human patients and/or patient-derived cardiomyocytes (iPSC-CMs), and various PLN-R14del animal models [12][13][14][15][16][17][18]. These studies have revealed multiple defects associated with the PLN-R14del mutation, including impaired Ca 2+ homeostasis [12][13][14]16,18], electrical remodeling [19], unfolded protein response (UPR) activation [20], and protein aggregation [15,21,22].…”

Section: Introductionmentioning

confidence: 99%

Aberrant PLN-R14del Protein Interactions Intensify SERCA2a Inhibition, Driving Impaired Ca2+ Handling and Arrhythmogenesis

Vafiadaki

Haghighi

Arvanitis

et al. 2022

IJMS

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Phospholamban (PLN), a key modulator of Ca2+-homeostasis, inhibits sarcoplasmic reticulum (SR) calcium-ATPase (SERCA2a) and regulates cardiac contractility. The human PLN mutation R14del has been identified in arrhythmogenic cardiomyopathy patients worldwide and is currently extensively investigated. In search of the molecular mechanisms mediating the pathological phenotype, we examined PLN-R14del associations to known PLN-interacting partners. We determined that PLN-R14del interactions to key Ca2+-handling proteins SERCA2a and HS-1-associated protein X-1 (HAX-1) were enhanced, indicating the super-inhibition of SERCA2a’s Ca2+-affinity. Additionally, histidine-rich calcium binding protein (HRC) binding to SERCA2a was increased, suggesting the inhibition of SERCA2a maximal velocity. As phosphorylation relieves the inhibitory effect of PLN on SERCA2a activity, we examined the impact of phosphorylation on the PLN-R14del/SERCA2a interaction. Contrary to PLN-WT, phosphorylation did not affect PLN-R14del binding to SERCA2a, due to a lack of Ser-16 phosphorylation in PLN-R14del. No changes were observed in the subcellular distribution of PLN-R14del or its co-localization to SERCA2a. However, in silico predictions suggest structural perturbations in PLN-R14del that could impact its binding and function. Οur findings reveal for the first time that by increased binding to SERCA2a and HAX-1, PLN-R14del acts as an enhanced inhibitor of SERCA2a, causing a cascade of molecular events contributing to impaired Ca2+-homeostasis and arrhythmogenesis. Relieving SERCA2a super-inhibition could offer a promising therapeutic approach for PLN-R14del patients.

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Section: Introductionmentioning

confidence: 99%

Aberrant PLN-R14del Protein Interactions Intensify SERCA2a Inhibition, Driving Impaired Ca2+ Handling and Arrhythmogenesis

Vafiadaki

Haghighi

Arvanitis

et al. 2022

IJMS

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“…GO term analysis did not identify overrepresentation of any terms in either gene set (false discovery rate <0.05). However, among the downregulated transcripts, we found three well-characterized myocardial genes including phospholamban ( pln/plna ), 63 , 64 atrial myosin heavy chain 6 ( myh6 ), 65 and natriuretic peptide precursor a ([ nppa ] 66 , 67 ; Figure S8B ; Table S3 ). We documented trending downregulation of nppa by reverse-transcription quantitative PCR (RT-qPCR) at 33 hpf ( Figure S7C ).…”

Section: Resultsmentioning

confidence: 99%

RBPMS2 Is a Myocardial-Enriched Splicing Regulator Required for Cardiac Function

Akerberg

Trembley

Butty

et al. 2022

Circulation Research

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Background: RBPs (RNA-binding proteins) perform indispensable functions in the post-transcriptional regulation of gene expression. Numerous RBPs have been implicated in cardiac development or physiology based on gene knockout studies and the identification of pathogenic RBP gene mutations in monogenic heart disorders. The discovery and characterization of additional RBPs performing indispensable functions in the heart will advance basic and translational cardiovascular research. Methods: We performed a differential expression screen in zebrafish embryos to identify genes enriched in nkx2.5 -positive cardiomyocytes or cardiopharyngeal progenitors compared to nkx2.5 -negative cells from the same embryos. We investigated the myocardial-enriched gene RNA-binding protein with multiple splicing (variants) 2 [ RBPMS2 )] by generating and characterizing rbpms2 knockout zebrafish and human cardiomyocytes derived from RBPMS2 -deficient induced pluripotent stem cells. Results: We identified 1848 genes enriched in nkx2.5 -positive population. Among the most highly enriched genes, most with well-established functions in the heart, we discovered the ohnologs rbpms2a and rbpms2b , which encode an evolutionarily conserved RBP. Rbpms2 localizes selectively to cardiomyocytes during zebrafish heart development and strong cardiomyocyte expression persists into adulthood. Rbpms2-deficient embryos suffer from early cardiac dysfunction characterized by reduced ejection fraction. The functional deficit is accompanied by myofibril disarray, altered calcium handling, and differential alternative splicing events in mutant cardiomyocytes. These phenotypes are also observed in RBPMS2 -deficient human cardiomyocytes, indicative of conserved molecular and cellular function. RNA-sequencing and comparative analysis of genes mis-spliced in RBPMS2 -deficient zebrafish and human cardiomyocytes uncovered a conserved network of 29 ortholog pairs that require RBPMS2 for alternative splicing regulation, including RBFOX2 , SLC8A1 , and MYBPC3 . Conclusions: Our study identifies RBPMS2 as a conserved regulator of alternative splicing, myofibrillar organization, and calcium handling in zebrafish and human cardiomyocytes.

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“…In Zebrafish, the plna R14del variant causes beat-to-beat variations in cardiac output in the absence of cardiac remodeling, suggesting that the cardiac contractile dysfunction is not caused by but rather causal for cardiac remodeling. 36 Causal relationships between anomalies in the QRS complex, specifically in the Q-R upslope, and increased risk of DCM have been found through the Mendelian Randomization approach using genetic variants of ECG signatures 37 .…”

Section: Discussionmentioning

confidence: 99%

Phenotypic and genetic factors are associated with absence of cardiomyopathy symptoms in PLN c.40_42delAGA carriers

Lopera-Maya

Brouwer

et al. 2022

Preprint

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The c.40_42delAGA variant in the phospholamban gene (PLN) has been associated with dilated and arrhythmogenic cardiomyopathy, with up to 70% of carriers experiencing a major cardiac event by age 70. However, other carriers remain asymptomatic or show only mild symptoms in old age. To understand the mechanisms behind this incomplete penetrance, we evaluated potential phenotypic and genetic modifiers in 74 PLN c.40_42delAGA carriers identified in 36,339 participants of the Lifelines population cohort. Asymptomatic carriers (N=48) showed shorter QRS duration (-5.73 ms, p-value=0.001) compared to asymptomatic non-carriers and symptomatic carriers (N=26), and we replicated this in different subset of 21,771 participants from the Lifelines cohort (-3.87 ms, p-value=0.028) and in 592 carriers from the Arrhythmogenic Cardiomyopathy (ACM) patient registry (-6.91 ms, p-value=0.0002). Furthermore, symptomatic carriers showed a higher correlation between genetic predisposition to higher QRS duration (PGSQRS) and QRS (p-value=1.98x10-8), suggesting that symptomatic PLN c.40_42delAGA carriers may have an increased sensitivity to the effect of genetic variation in cardiac rhythm. Our results may help improve risk prediction models for cardiac outcomes for future studies, while our approach could guide studies on genetic diseases with incomplete penetrance.

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Istaroxime treatment ameliorates calcium dysregulation in a zebrafish model of phospholamban R14del cardiomyopathy

Cited by 25 publications

References 66 publications

Aberrant PLN-R14del Protein Interactions Intensify SERCA2a Inhibition, Driving Impaired Ca2+ Handling and Arrhythmogenesis

Aberrant PLN-R14del Protein Interactions Intensify SERCA2a Inhibition, Driving Impaired Ca2+ Handling and Arrhythmogenesis

RBPMS2 Is a Myocardial-Enriched Splicing Regulator Required for Cardiac Function

Phenotypic and genetic factors are associated with absence of cardiomyopathy symptoms in PLN c.40_42delAGA carriers

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