@article{ZinkSeewaldRohrbachetal.2022, author = {Zink, Miriam and Seewald, Anne and Rohrbach, Mareike and Brodehl, Andreas and Liedtke, Daniel and Williams, Tatjana and Childs, Sarah J. and Gerull, Brenda}, title = {Altered expression of TMEM43 causes abnormal cardiac structure and function in zebrafish}, series = {International Journal of Molecular Sciences}, volume = {23}, journal = {International Journal of Molecular Sciences}, number = {17}, issn = {1422-0067}, doi = {10.3390/ijms23179530}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286025}, year = {2022}, abstract = {Arrhythmogenic cardiomyopathy (ACM) is an inherited heart muscle disease caused by heterozygous missense mutations within the gene encoding for the nuclear envelope protein transmembrane protein 43 (TMEM43). The disease is characterized by myocyte loss and fibro-fatty replacement, leading to life-threatening ventricular arrhythmias and sudden cardiac death. However, the role of TMEM43 in the pathogenesis of ACM remains poorly understood. In this study, we generated cardiomyocyte-restricted transgenic zebrafish lines that overexpress eGFP-linked full-length human wild-type (WT) TMEM43 and two genetic variants (c.1073C>T, p.S358L; c.332C>T, p.P111L) using the Tol2-system. Overexpression of WT and p.P111L-mutant TMEM43 was associated with transcriptional activation of the mTOR pathway and ribosome biogenesis, and resulted in enlarged hearts with cardiomyocyte hypertrophy. Intriguingly, mutant p.S358L TMEM43 was found to be unstable and partially redistributed into the cytoplasm in embryonic and adult hearts. Moreover, both TMEM43 variants displayed cardiac morphological defects at juvenile stages and ultrastructural changes within the myocardium, accompanied by dysregulated gene expression profiles in adulthood. Finally, CRISPR/Cas9 mutants demonstrated an age-dependent cardiac phenotype characterized by heart enlargement in adulthood. In conclusion, our findings suggest ultrastructural remodeling and transcriptomic alterations underlying the development of structural and functional cardiac defects in TMEM43-associated cardiomyopathy.}, language = {en} } @article{GerullBrodehl2020, author = {Gerull, Brenda and Brodehl, Andreas}, title = {Genetic Animal Models for Arrhythmogenic Cardiomyopathy}, series = {Frontiers in Physiology}, volume = {11}, journal = {Frontiers in Physiology}, number = {264}, issn = {1664-042X}, doi = {10.3389/fphys.2020.00624}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-206903}, year = {2020}, abstract = {Arrhythmogenic cardiomyopathy has been clinically defined since the 1980s and causes right or biventricular cardiomyopathy associated with ventricular arrhythmia. Although it is a rare cardiac disease, it is responsible for a significant proportion of sudden cardiac deaths, especially in athletes. The majority of patients with arrhythmogenic cardiomyopathy carry one or more genetic variants in desmosomal genes. In the 1990s, several knockout mouse models of genes encoding for desmosomal proteins involved in cell-cell adhesion revealed for the first time embryonic lethality due to cardiac defects. Influenced by these initial discoveries in mice, arrhythmogenic cardiomyopathy received an increasing interest in human cardiovascular genetics, leading to the discovery of mutations initially in desmosomal genes and later on in more than 25 different genes. Of note, even in the clinic, routine genetic diagnostics are important for risk prediction of patients and their relatives with arrhythmogenic cardiomyopathy. Based on improvements in genetic animal engineering, different transgenic, knock-in, or cardiac-specific knockout animal models for desmosomal and nondesmosomal proteins have been generated, leading to important discoveries in this field. Here, we present an overview about the existing animal models of arrhythmogenic cardiomyopathy with a focus on the underlying pathomechanism and its importance for understanding of this disease. Prospectively, novel mechanistic insights gained from the whole animal, organ, tissue, cellular, and molecular levels will lead to the development of efficient personalized therapies for treatment of arrhythmogenic cardiomyopathy.}, language = {en} } @article{GerullBrodehl2021, author = {Gerull, Brenda and Brodehl, Andreas}, title = {Insights Into Genetics and Pathophysiology of Arrhythmogenic Cardiomyopathy}, series = {Current Heart Failure Reports}, volume = {18}, journal = {Current Heart Failure Reports}, number = {6}, issn = {1546-9549}, doi = {10.1007/s11897-021-00532-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-269916}, pages = {378-390}, year = {2021}, abstract = {Purpose of Review Arrhythmogenic cardiomyopathy (ACM) is a genetic disease characterized by life-threatening ventricular arrhythmias and sudden cardiac death (SCD) in apparently healthy young adults. Mutations in genes encoding for cellular junctions can be found in about half of the patients. However, disease onset and severity, risk of arrhythmias, and outcome are highly variable and drug-targeted treatment is currently unavailable. Recent Findings This review focuses on advances in clinical risk stratification, genetic etiology, and pathophysiological concepts. The desmosome is the central part of the disease, but other intercalated disc and associated structural proteins not only broaden the genetic spectrum but also provide novel molecular and cellular insights into the pathogenesis of ACM. Signaling pathways and the role of inflammation will be discussed and targets for novel therapeutic approaches outlined. Summary Genetic discoveries and experimental-driven preclinical research contributed significantly to the understanding of ACM towards mutation- and pathway-specific personalized medicine.}, language = {en} } @article{BrodehlPourHakimiStanasiuketal.2019, author = {Brodehl, Andreas and Pour Hakimi, Seyed Ahmad and Stanasiuk, Caroline and Ratnavadivel, Sandra and Hendig, Doris and Gaertner, Anna and Gerull, Brenda and Gummert, Jan and Paluszkiewicz, Lech and Milting, Hendrik}, title = {Restrictive cardiomyopathy is caused by a novel homozygous desmin (DES) mutation p.Y122H leading to a severe filament assembly defect}, series = {Genes}, volume = {10}, journal = {Genes}, number = {11}, issn = {2073-4425}, doi = {10.3390/genes10110918}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-193121}, year = {2019}, abstract = {Here, we present a small Iranian family, where the index patient received a diagnosis of restrictive cardiomyopathy (RCM) in combination with atrioventricular (AV) block. Genetic analysis revealed a novel homozygous missense mutation in the DES gene (c.364T > C; p.Y122H), which is absent in human population databases. The mutation is localized in the highly conserved coil-1 desmin subdomain. In silico, prediction tools indicate a deleterious effect of the desmin (DES) mutation p.Y122H. Consequently, we generated an expression plasmid encoding the mutant and wildtype desmin formed, and analyzed the filament formation in vitro in cardiomyocytes derived from induced pluripotent stem cells and HT-1080 cells. Confocal microscopy revealed a severe filament assembly defect of mutant desmin supporting the pathogenicity of the DES mutation, p.Y122H, whereas the wildtype desmin formed regular intermediate filaments. According to the guidelines of the American College of Medical Genetics and Genomics, we classified this mutation, therefore, as a novel pathogenic mutation. Our report could point to a recessive inheritance of the DES mutation, p.Y122H, which is important for the genetic counseling of similar families with restrictive cardiomyopathy caused by DES mutations.}, language = {en} } @article{BrodehlMiltingGerull2021, author = {Brodehl, Andreas and Milting, Hendrik and Gerull, Brenda}, title = {Special Issue "Cardiovascular Genetics"}, series = {Genes}, volume = {12}, journal = {Genes}, number = {4}, issn = {2073-4425}, doi = {10.3390/genes12040479}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-234229}, year = {2021}, abstract = {No abstract available}, language = {en} } @article{BrodehlMeshkovMyasnikovetal.2021, author = {Brodehl, Andreas and Meshkov, Alexey and Myasnikov, Roman and Kiseleva, Anna and Kulikova, Olga and Klauke, B{\"a}rbel and Sotnikova, Evgeniia and Stanasiuk, Caroline and Divashuk, Mikhail and Pohl, Greta Marie and Kudryavtseva, Maria and Klingel, Karin and Gerull, Brenda and Zharikova, Anastasia and Gummert, Jan and Koretskiy, Sergey and Schubert, Stephan and Mershina, Elena and G{\"a}rtner, Anna and Pilus, Polina and Laser, Kai Thorsten and Sinitsyn, Valentin and Boytsov, Sergey and Drapkina, Oxana and Milting, Hendrik}, title = {Hemi- and homozygous loss-of-function mutations in DSG2 (desmoglein-2) cause recessive arrhythmogenic cardiomyopathy with an early onset}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {7}, issn = {1422-0067}, doi = {10.3390/ijms22073786}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-285279}, year = {2021}, abstract = {About 50\% of patients with arrhythmogenic cardiomyopathy (ACM) carry a pathogenic or likely pathogenic mutation in the desmosomal genes. However, there is a significant number of patients without positive familial anamnesis. Therefore, the molecular reasons for ACM in these patients are frequently unknown and a genetic contribution might be underestimated. Here, we used a next-generation sequencing (NGS) approach and in addition single nucleotide polymor-phism (SNP) arrays for the genetic analysis of two independent index patients without familial medical history. Of note, this genetic strategy revealed a homozygous splice site mutation (DSG2-c.378+1G>T) in the first patient and a nonsense mutation (DSG2-p.L772X) in combination with a large deletion in DSG2 in the second one. In conclusion, a recessive inheritance pattern is likely for both cases, which might contribute to the hidden medical history in both families. This is the first report about these novel loss-of-function mutations in DSG2 that have not been previously identi-fied. Therefore, we suggest performing deep genetic analyses using NGS in combination with SNP arrays also for ACM index patients without obvious familial medical history. In the future, this finding might has relevance for the genetic counseling of similar cases.}, language = {en} } @article{BrodehlGerull2022, author = {Brodehl, Andreas and Gerull, Brenda}, title = {Genetic insights into primary restrictive cardiomyopathy}, series = {Journal of Clinical Medicine}, volume = {11}, journal = {Journal of Clinical Medicine}, number = {8}, issn = {2077-0383}, doi = {10.3390/jcm11082094}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-270621}, year = {2022}, abstract = {Restrictive cardiomyopathy is a rare cardiac disease causing severe diastolic dysfunction, ventricular stiffness and dilated atria. In consequence, it induces heart failure often with preserved ejection fraction and is associated with a high mortality. Since it is a poor clinical prognosis, patients with restrictive cardiomyopathy frequently require heart transplantation. Genetic as well as non-genetic factors contribute to restrictive cardiomyopathy and a significant portion of cases are of unknown etiology. However, the genetic forms of restrictive cardiomyopathy and the involved molecular pathomechanisms are only partially understood. In this review, we summarize the current knowledge about primary genetic restrictive cardiomyopathy and describe its genetic landscape, which might be of interest for geneticists as well as for cardiologists.}, language = {en} } @article{BrodehlBelkeGarnettetal.2017, author = {Brodehl, Andreas and Belke, Darrell D. and Garnett, Lauren and Martens, Kristina and Abdelfatah, Nelly and Rodriguez, Marcela and Diao, Catherine and Chen, Yong-Xiang and Gordon, Paul M. K. and Nygren, Anders and Gerull, Brenda}, title = {Transgenic mice overexpressing desmocollin-2 (DSC2) develop cardiomyopathy associated with myocardial inflammation and fibrotic remodeling}, series = {PLoS ONE}, volume = {12}, journal = {PLoS ONE}, number = {3}, doi = {10.1371/journal.pone.0174019}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171084}, pages = {e0174019}, year = {2017}, abstract = {Background Arrhythmogenic cardiomyopathy is an inherited heart muscle disorder leading to ventricular arrhythmias and heart failure, mainly as a result of mutations in cardiac desmosomal genes. Desmosomes are cell-cell junctions mediating adhesion of cardiomyocytes; however, the molecular and cellular mechanisms underlying the disease remain widely unknown. Desmocollin-2 is a desmosomal cadherin serving as an anchor molecule required to reconstitute homeostatic intercellular adhesion with desmoglein-2. Cardiac specific lack of desmoglein-2 leads to severe cardiomyopathy, whereas overexpression does not. In contrast, the corresponding data for desmocollin-2 are incomplete, in particular from the view of protein overexpression. Therefore, we developed a mouse model overexpressing desmocollin-2 to determine its potential contribution to cardiomyopathy and intercellular adhesion pathology. Methods and results We generated transgenic mice overexpressing DSC2 in cardiac myocytes. Transgenic mice developed a severe cardiac dysfunction over 5 to 13 weeks as indicated by 2D-echocardiography measurements. Corresponding histology and immunohistochemistry demonstrated fibrosis, necrosis and calcification which were mainly localized in patches near the epi- and endocardium of both ventricles. Expressions of endogenous desmosomal proteins were markedly reduced in fibrotic areas but appear to be unchanged in non-fibrotic areas. Furthermore, gene expression data indicate an early up-regulation of inflammatory and fibrotic remodeling pathways between 2 to 3.5 weeks of age. Conclusion Cardiac specific overexpression of desmocollin-2 induces necrosis, acute inflammation and patchy cardiac fibrotic remodeling leading to fulminant biventricular cardiomyopathy.}, language = {en} }