Desmoplakin Research Articles

Success of Immunopathogenetic Therapy for Management of Congenital Ichthyosis, Combined Form, in a Child: Rare Clinical Case

Background. Congenital ichthyosis (CI) is relating to the group of clinical and genetically heterogeneous severe genodermatoses. SAM syndrome is included in classification of CI syndromic forms. Defects in the desmoplakin (DSP) and desmoglein 1 (DSG1) genes are the prime cause of disease. Impaired function of encoded proteins leads to desmosomal anomalies and disease symptoms. Comorbid atopic syndrome becomes the major cause of diagnostic mistakes. Patients are observed continuously with diagnosis “Atopic dermatitis (AD) torpid to standard treatment methods”. Clinical case description. This article describes a rare case of a boy with severe AD. Despite the chronic dermatosis several systemic disorders were revealed during examination: short stature, protein-energy malnutrition, adrenal insufficiency, juvenile polyarthritis, vitamin D deficiency, onychodystrophy, dysmorphic disorders. Molecular genetic study conducted via high-throughput sequencing followed by validation with Sanger sequencing has revealed two genetic variants: novel variant chr18:28934543G>T in the DSG1 gene in the heterozygous state and pathogenic variant chr5:157468728C>A in the NIPAL4 gene in the homozygous state. As a result, the final diagnosis was established: “SAM syndrome. Congenital ichthyosiform erythroderma”. Flow cytometry immunology study has shown dominant immunological profile of Th17-, and Thact-lymphocyte proliferation. The immunobiological therapy with IL-17A inhibitor, secukinumab, was initiated. Clinical efficacy was evaluated via ISS (Ichthyosis Severity Index), CDLQI (Children’s Dermatology Life Quality Index), pruritus numerical rating scale. ISS was 5.8 points, pruritus scale — 9, CDLQI — 24 at therapy initiation. Improvement in the skin condition was observed after a month of therapy. ISS was 1.2 points, pruritus scale — 2, CDLQI — 4 6 months after the therapy initiation. Conclusion. The diagnosis of a child with combined form of CI made it possible to change the management strategy, to prescribe pathogenetically justified targeted immunobiological therapy, and to achieve significant improvement in the child's health and quality of life, which does not differ from healthy peers.

Protein redistribution in buccal cells as a prognostic marker for arrhythmogenic cardiomyopathy in paediatric patients

Abstract Background Mutations in genes encoding desmosomal proteins [plakoglobin (JUP), desmoplakin (DSP), plakophilin-2 (PKP2), desmoglein-2 (DSG2) and desmocollin-2 (DSC2)] cause complex genetic heart muscle disorders collectively described as arrhythmogenic cardiomyopathies (ACM). Diagnosis and risk stratification, particularly in the paediatric population, remain challenging owing to heterogeneous phenotypic manifestations and reduced genetic penetrance. Immunohistochemical analysis of heart muscle samples has shown that several junctional and signalling molecules are redistributed in patients with ACM, offering diagnostic information. However, the use of this approach in living patients was limited by need for heart samples. Recent studies in adults with ACM showed that the same set of proteins re-localised in the ACM heart also do so in the buccal epithelium. Purpose Given the ease of analysing serial cheek smears, we sought to establish how protein redistribution in buccal cells relates to disease onset and progression in children bearing desmosomal gene mutations. Methods Serial cheek smears from children with desmosomal variants were subjected to immunocytochemistry and confocal microscopy to study the distribution of JUP, DSP and PKP-1 as well as the major gap junction protein connexin43 (Cx43; GJA1) and the major subunit of the NFκB inflammatory pathway; RelA. Results 37 patients Conclusion These data indicate that shifts in junctional/signalling proteins precede the onset of clinical disease. Indeed, in the majority of pre-clinical children, Cx43 and RelA seem to be redistributed first, suggesting that onset of abnormalities in electrical conductivity and inflammatory pathways occur first in the natural disease progression, in agreement with previous clinical observations. Moreover, the data suggest that additional proteins are shifted as the disease progresses. Although further verification is required, this study suggests that analysis of buccal smears may be used as a prognostic/risk stratification test in children with desmosomal variants.

Clinical features and outcomes in carriers of pathogenic desmoplakin variants.

Pathogenic variants in the desmoplakin (DSP) gene are associated with the development of a distinct arrhythmogenic cardiomyopathy phenotype not fully captured by either dilated cardiomyopathy (DCM), non-dilated left ventricular cardiomyopathy (NDLVC), or arrhythmogenic right ventricular cardiomyopathy (ARVC). Prior studies have described baseline DSP cardiomyopathy genetic, inflammatory, and structural characteristics. However, cohort sizes have limited full clinical characterization and identification of clinical and demographic predictors of sustained ventricular arrhythmias (VAs), heart failure (HF) hospitalizations, and transplant/death. In particular, the relevance of acute myocarditis-like episodes for subsequent disease course is largely unknown. All patients with pathogenic/likely pathogenic (P/LP) DSP variants in the worldwide DSP-ERADOS Network (26 academic institutions across nine countries) were included. The primary outcomes were the development of sustained VA and HF hospitalizations during follow-up. Fine-Gray regressions were used to test association between clinical and instrumental parameters and the development of outcomes. Eight hundred patients [40.3 ± 17.5 years, 47.5% probands, left ventricular ejection fraction (LVEF) 49.5 ± 13.9%] were included. Over 3.7 [1.4-7.1] years, 139 (17.4%, 3.9%/year) and 72 (9.0%, 1.8%/year) patients experienced sustained VA and HF episodes, respectively. A total of 32.5% of individuals did not fulfil diagnostic criteria for ARVC, DCM, or NDLVC; their VA incidence was 0.5%/year. In multivariable regression, risk features associated with the development of VA were female sex [adjusted hazard ratio (aHR) 1.547; P = .025], prior non-sustained ventricular tachycardia (aHR 1.721; P = .009), prior sustained VA (aHR 1.923; P = .006), and LVEF ≤ 50% (aHR: 1.645; P = .032), while for HF, they were the presence of T-wave inversion in 3+ electrocardiogram leads (aHR 2.036, P = .007) and LVEF ≤ 50% (aHR 3.879; P < .001). Additionally, 70 (8.8%) patients experienced a myocardial injury episode at presentation or during follow-up. These episodes were associated with an increased risk of VA and HF thereafter (HR 2.394; P < .001, and HR 5.064, P < .001, respectively). Patients with P/LP DSP variants experience high rates of sustained VA and HF hospitalizations. These patients demonstrate a distinct clinical phenotype (DSP cardiomyopathy), whose most prominent risk features associated with adverse clinical outcomes are the presence of prior non-sustained ventricular tachycardia or sustained VA, T-wave inversion in 3+ leads on electrocardiogram, LVEF ≤ 50%, and myocardial injury events.

Desmoplakin mutations in cardiac fibroblasts cause TGFβ1-mediated pathological fibrogenesis in desmoplakin cardiomyopathy via beclin-1 regulation.

Pathological fibrosis is a major finding in cardiovascular diseases and can result in arrhythmia and heart failure. Desmosome gene mutations can lead to arrhythmogenic cardiomyopathy (ACM). Among ACM, pathogenic desmoplakin ( DSP ) variants cause a distinctive cardiomyopathy with excessive cardiac fibrosis that could precede ventricular dysfunction. DSP variants are also linked to other fibrotic diseases. Whether DSP plays any role in pathological fibrosis remain unknown. Mesenchymal stromal cells (MSCs) are resident fibroblast-like cells that are responsible for fibrogenesis in most organs, including hearts. We first used unbiased genome-wide analyses to generate cardiac fibroblasts-like, induced pluripotent stem cell-derived MSCs from normal donors and ACM patients with DSP mutations. We then studied the fibrogenic responses of cardiac MSCs to transforming growth factor beta-1 (TGF-β1) using Western/Co-IP, autophagy assay, gene knockdowns/over-expressions, genomic analyses, mouse DSP knockdown models, immunostaining, and qPCR. TGFβ1 induced excessive accumulations of vimentin (VIM)/fibrillar collagens, and over-activated fibrotic genes in DSP- mutant MSCs when compared to normal MSCs. In normal MSCs, VIMs bind to wild-type DSP during normal fibrogenesis after TGFβ1. DSP- mutant MSCs exhibited a haplo-insufficient phenotype with increased DSP-unbound VIMs that sequestered beclin-1 (BECN1) from activating autophagy and caveolin-1 (CAV1)-mediated endocytosis. Decreased autophagy caused collagen accumulations and diminished CAV1 endocytosis resulted in abnormal CAV1 plaque formation that over-activated fibrotic genes [ COL1A1, COL3A1, and fibronectin ( FN )] via heightened p38 activities after TGFβ1. Genome-wide analysis and DSP knockdown in mouse fibroblasts confirmed this novel role of DSP mutations in pathological fibrosis. Overexpression of VIM-binding domains of DSP could suppress pathological fibrosis by increasing collagen autophagic degradation and decreasing fibrotic gene expressions. Our data reveal that DSP deficiency in MSCs/fibroblasts leads to exaggerated fibrogenesis in DSP-cardiomyopathy by decreasing BECN1 availability for autophagy and CAV1-endocytosis. Overexpression of VIM binding domains of DSP could be a new strategy to treat pathological fibrosis.

Death-associated protein kinase 3 modulates migration and invasion of triple-negative breast cancer cells.

Sixteen patient-derived xenografts (PDXs) were analyzed using a mass spectrometry (MS)-based kinase inhibitor pull-down assay (KIPA), leading to the observation that death-associated protein kinase 3 (DAPK3) is significantly and specifically overexpressed in the triple-negative breast cancer (TNBC) models. Validation studies confirmed enrichment of DAPK3 protein, in both TNBC cell lines and tumors, independent of mRNA levels. Genomic knockout of DAPK3 in TNBC cell lines inhibited in vitro migration and invasion, along with down-regulation of an epithelial-mesenchymal transition (EMT) signature, which was confirmed in vivo. The kinase and leucine-zipper domains within DAPK3 were shown by a mutational analysis to be essential for functionality. Notably, DAPK3 was found to inhibit the levels of desmoplakin (DSP), a crucial component of the desmosome complex, thereby explaining the observed migration and invasion effects. Further exploration with immunoprecipitation-mass spectrometry (IP-MS) identified that leucine-zipper protein 1 (LUZP1) is a preferential binding partner of DAPK3. LUZP1 engages in a leucine-zipper domain-mediated interaction that protects DAPK3 from proteasomal degradation. Thus, the DAPK3/LUZP1 heterodimer emerges as a newly discovered regulator of EMT/desmosome components that promote TNBC cell migration.

Generation of a human induced pluripotent stem cell line UGENTi002-A from an arrhythmogenic cardiomyopathy patient carrying the c.817C>T DSP heterozygous variant and isogenic control using CRISPR/Cas9 editing

Arrhythmogenic cardiomyopathy is a severe genetic heart muscle disease characterized by fibro-fatty replacement of the myocardium. Pathogenic variants causal for this disease are mainly located in desmosomal genes, including desmoplakin (DSP). Renal epithelial cells were isolated from a patient carrying the heterozygous c.817C>T (p.Q273*, nonsense) pathogenic variant in DSP, and subsequently reprogrammed using the Cytotune®-iPS 2.0 Sendai Reprogramming Kit. An isogenic control line was generated using CRISPR/Cas9 genome editing. The resulting induced pluripotent stem cell lines were characterized and displayed the required traits for in vitro disease modeling.

The desmosome-intermediate filament system facilitates mechanotransduction at adherens junctions for epithelial homeostasis

Epithelial homeostasis can be critically influenced by how cells respond to mechanical forces, both local changes in force balance between cells and altered tissue-level forces.1 Coupling of specialized cell-cell adhesions to their cytoskeletons provides epithelia with diverse strategies to respond to mechanical stresses.2,3,4 Desmosomes confer tissue resilience when their associated intermediate filaments (IFs)2,3 stiffen in response to strain,5,6,7,8,9,10,11 while mechanotransduction associated with the E-cadherin apparatus12,13 at adherens junctions (AJs) actively modulates actomyosin by RhoA signaling. Although desmosomes and AJs make complementary contributions to mechanical homeostasis in epithelia,6,8 there is increasing evidence to suggest that these cytoskeletal-adhesion systems can interact functionally and biochemically.8,14,15,16,17,18,19,20 We now report that the desmosome-IF system integrated by desmoplakin (DP) facilitates active tension sensing at AJs for epithelial homeostasis. DP function is necessary for mechanosensitive RhoA signaling at AJs to be activated when tension was applied to epithelial monolayers. This effect required DP to anchor IFs to desmosomes and recruit the dystonin (DST) cytolinker to apical junctions. DP RNAi reduced the mechanical load that was applied to the cadherin complex by increased monolayer tension. Consistent with reduced mechanical signal strength, DP RNAi compromised assembly of the Myosin VI-E-cadherin mechanosensor that activates RhoA. The integrated DP-IF system therefore supports AJ mechanotransduction by enhancing the mechanical load of tissue tension that is transmitted to E-cadherin. This crosstalk was necessary for efficient elimination of apoptotic epithelial cells by apical extrusion, demonstrating its contribution to epithelial homeostasis.

Abstract Mo046: GJA1-20k Restores Connexin-43 Trafficking and β-Catenin Signaling in Myocytes Lacking Desmoplakin

Background: Arrhythmogenic Cardiomyopathy (ACM) is an insidious hereditary heart disease that results in structural and electrical cardiac abnormalities leading to arrhythmogenesis and heart failure. ACM is characterized by cardiomyocyte loss, decreased cellular coupling, and fibrofatty replacement. The disease arises from mutations in desmosomal genes, such as plakophilin (PKP), desmoglein (DSG), and desmoplakin (DSP). The pathogenesis of this disease is linked to dysfunction at the level of several cellular processes and pathways, including Wnt/β-catenin signaling. Recent evidence has shown that GJA1-20k, a truncated isoform of Connexin-43 (Cx43) generated by internal translation, has a therapeutic role in preserving Cx43 trafficking and cell-cell coupling in ACM of DSG origin. This study aims to investigate the role of GJA1-20k in protecting against ACM of DSP origin by evaluating its effect in cell models on Cx43 trafficking and Wnt/β-catenin signaling. Methods: DSP knockdown was performed on HEK cells and mouse neonatal cardiomyocytes. The role of GJA1-20k was determined using imaging, biochemical, and molecular biology techniques. Results: Protein levels of Cx43 and β-catenin were decreased on Western blot (WB) upon DSP knockdown. These findings were corroborated through imaging wherein the signal intensity for Cx43 at cellular junctions and β-catenin at the membrane was significantly decreased compared to the control group. β-catenin signal intensity was also decreased within the nucleus. Upon administration of GJA1-20k, protein levels of Cx43 were normalized on WB. Moreover, the ratio of phosphorylated β-catenin (inactive) to total β-catenin was decreased. Imaging studies identified a significant increase in Cx43 and β-catenin at the membrane in ACM models treated with GJA1-20k. This was also accompanied by an increase in β-catenin signal intensity within the nucleus. A TOP-flash luciferase assay was performed and revealed a significant increase in β-catenin transcriptional activity in the presence of GJA1-20k despite DSP knockdown. Conclusions: These results suggest that GJA1-20k is able to rescue Cx43 trafficking and recover Wnt/β-catenin signaling in cells and cardiomyocytes lacking DSP. The ability of GJA1-20k to restore dysfunctional genetic pathways involved in arrhythmogenesis and fibro-adipogenesis make it an attractive potential candidate for targeted therapy against ACM.

A novel tool for arrhythmic risk stratification in desmoplakin gene variant carriers.

Pathogenic desmoplakin (DSP) gene variants are associated with the development of a distinct form of arrhythmogenic cardiomyopathy known as DSP cardiomyopathy. Patients harbouring these variants are at high risk for sustained ventricular arrhythmia (VA), but existing tools for individualized arrhythmic risk assessment have proven unreliable in this population. Patients from the multi-national DSP-ERADOS (Desmoplakin SPecific Effort for a RAre Disease Outcome Study) Network patient registry who had pathogenic or likely pathogenic DSP variants and no sustained VA prior to enrolment were followed longitudinally for the development of first sustained VA event. Clinically guided, step-wise Cox regression analysis was used to develop a novel clinical tool predicting the development of incident VA. Model performance was assessed by c-statistic in both the model development cohort (n = 385) and in an external validation cohort (n = 86). In total, 471 DSP patients [mean age 37.8 years, 65.6% women, 38.6% probands, 26% with left ventricular ejection fraction (LVEF) < 50%] were followed for a median of 4.0 (interquartile range: 1.6-7.3) years; 71 experienced first sustained VA events {2.6% [95% confidence interval (CI): 2.0, 3.5] events/year}. Within the development cohort, five readily available clinical parameters were identified as independent predictors of VA and included in a novel DSP risk score: female sex [hazard ratio (HR) 1.9 (95% CI: 1.1-3.4)], history of non-sustained ventricular tachycardia [HR 1.7 (95% CI: 1.1-2.8)], natural logarithm of 24-h premature ventricular contraction burden [HR 1.3 (95% CI: 1.1-1.4)], LVEF < 50% [HR 1.5 (95% CI: .95-2.5)], and presence of moderate to severe right ventricular systolic dysfunction [HR 6.0 (95% CI: 2.9-12.5)]. The model demonstrated good risk discrimination within both the development [c-statistic .782 (95% CI: .77-.80)] and external validation [c-statistic .791 (95% CI: .75-.83)] cohorts. The negative predictive value for DSP patients in the external validation cohort deemed to be at low risk for VA (<5% at 5 years; n = 26) was 100%. The DSP risk score is a novel model that leverages readily available clinical parameters to provide individualized VA risk assessment for DSP patients. This tool may help guide decision-making for primary prevention implantable cardioverter-defibrillator placement in this high-risk population and supports a gene-first risk stratification approach.

Limitations of Whole Exome Sequencing Panels: Subsequent Identification of a Missed Pathogenic Large Deletion in Desmoplakin (DSP)

Limitations of Whole Exome Sequencing Panels: Subsequent Identification of a Missed Pathogenic Large Deletion in Desmoplakin (DSP)

Animal Models and Molecular Pathogenesis of Arrhythmogenic Cardiomyopathy Associated with Pathogenic Variants in Intercalated Disc Genes.

Arrhythmogenic cardiomyopathy (ACM) is a rare genetic cardiac disease characterized by the progressive substitution of myocardium with fibro-fatty tissue. Clinically, ACM shows wide variability among patients; symptoms can include syncope and ventricular tachycardia but also sudden death, with the latter often being its sole manifestation. Approximately half of ACM patients have been found with variations in one or more genes encoding cardiac intercalated discs proteins; the most involved genes are plakophilin 2 (PKP2), desmoglein 2 (DSG2), and desmoplakin (DSP). Cardiac intercalated discs provide mechanical and electro-metabolic coupling among cardiomyocytes. Mechanical communication is guaranteed by the interaction of proteins of desmosomes and adheren junctions in the so-called area composita, whereas electro-metabolic coupling between adjacent cardiac cells depends on gap junctions. Although ACM has been first described almost thirty years ago, the pathogenic mechanism(s) leading to its development are still only partially known. Several studies with different animal models point to the involvement of the Wnt/β-catenin signaling in combination with the Hippo pathway. Here, we present an overview about the existing murine models of ACM harboring variants in intercalated disc components with a particular focus on the underlying pathogenic mechanisms. Prospectively, mechanistic insights into the disease pathogenesis will lead to the development of effective targeted therapies for ACM.

Genomic analysis of severe COVID-19 considering or not asthma comorbidity: GWAS insights from the BQC19 cohort

BackgroundThe severity of COVID-19 is influenced by various factors including the presence of respiratory diseases. Studies have indicated a potential relationship between asthma and COVID-19 severity.ObjectiveThis study aimed to conduct a genome-wide association study (GWAS) to identify genetic and clinical variants associated with the severity of COVID-19, both among patients with and without asthma.MethodsWe analyzed data from 2131 samples sourced from the Biobanque québécoise de la COVID-19 (BQC19), with 1499 samples from patients who tested positive for COVID-19. Among these, 1110 exhibited mild-to-moderate symptoms, 389 had severe symptoms, and 58 had asthma. We conducted a comparative analysis of clinical data from individuals in these three groups and GWAS using a logistic regression model. Phenotypic data analysis resulted in the refined covariates integrated into logistic models for genetic studies.ResultsConsidering a significance threshold of 1 × 10−6, seven genetic variants were associated with severe COVID-19. These variants were located proximal to five genes: sodium voltage-gated channel alpha subunit 1 (SCN10A), desmoplakin (DSP), RP1 axonemal microtubule associated (RP1), IGF like family member 1 (IGFL1), and docking protein 5 (DOK5). The GWAS comparing individuals with severe COVID-19 with asthma to those without asthma revealed four genetic variants in transmembrane protein with EGF like and two follistatin like domains 2 (TMEFF2) and huntingtin interacting protein-1 (HIP1) genes.ConclusionThis study provides significant insights into the genetic profiles of patients with severe forms of the disease, whether accompanied by asthma or not. These findings enhance our comprehension of the genetic factors that affect COVID-19 severity.Key messagesSeven genetic variants were associated with the severe form of COVID-19;Four genetic variants were associated with the severe form of COVID-19 in individuals with comorbid asthma;These findings help define the genetic component of the severe form of COVID-19 in relation to asthma as a comorbidity.

Epidermal growth factor receptor inhibition leads to cellular phenotype correction of DSP-mutated keratinocytes.

Desmoplakin (DSP) is a desmosomal component expressed in skin and heart, essential for desmosome stability and intermediate filament connection. Pathogenic variants in the DSP gene encoding DSP, lead to heterogeneous skin, adnexa and heart-related phenotypes, including skin fragility, woolly hair (WH), palmoplantar keratoderma (PPK) and arrhythmogenic/dilated cardiomyopathy (ACM/DCM). The ambiguity of computer-based prediction analysis of pathogenicity and effect of DSP variants, indicates a necessity for functional analysis. Here, we report a heterozygous DSP variant that was not previously described, NM_004415.4:c.3337C>T (NM_004415.4(NP_004406.2):p.(Arg1113*)) in a patient with PPK, WH and ACM. RNA and protein analysis revealed ~50% reduction of DSP mRNA and protein expression. Patient's keratinocytes showed fragile cell-cell connections and perinuclear retracted intermediate filaments. Epidermal growth factor receptor (EGFR) is a transmembrane protein expressed in the basal epidermal layer involved in proliferation and differentiation, processes that are disrupted in the development of PPK, and in the regulation of the desmosome. In skin of the abovementioned patient, evident EGFR upregulation was observed. EGFR inhibition in patient's keratinocytes strongly increased DSP expression at the plasma membrane, improved intermediate filament connection with the membrane edges and reduced the cell-cell fragility. This cell phenotypic recovery was due to a translocation of DSP to the plasma membrane together with an increased number of desmosomes. These results indicate a therapeutic potential of EGFR inhibitors for disorders caused by DSP haploinsufficiency.

Imagenetics for Precision Medicine in Dilated Cardiomyopathy.

Dilated cardiomyopathy (DCM) is a common heart muscle disorder of nonischemic etiology associated with heart failure development and the risk of malignant ventricular arrhythmias and sudden cardiac death. A tailored approach to risk stratification and prevention of sudden cardiac death is required in genetic DCM given its variable presentation and phenotypic severity. Currently, advances in cardiogenetics have shed light on disease mechanisms, the complex genetic architecture of DCM, polygenic contributors to disease susceptibility and the role of environmental triggers. Parallel advances in imaging have also enhanced disease recognition and the identification of the wide spectrum of phenotypes falling under the DCM umbrella. Genotype-phenotype associations have been also established for specific subtypes of DCM, such as DSP (desmoplakin) or FLNC (filamin-C) cardiomyopathy but overall, they remain elusive and not readily identifiable. Also, despite the accumulated knowledge on disease mechanisms, certain aspects remain still unclear, such as which patients with DCM are at risk for disease progression or remission after treatment. Imagenetics, that is, the combination of imaging and genetics, is expected to further advance research in the field and contribute to precision medicine in DCM management and treatment. In the present article, we review the existing literature in the field, summarize the established knowledge and emerging data on the value of genetics and imaging in establishing genotype-phenotype associations in DCM and in clinical decision making for DCM patients.

Labeled-free quantitative proteomic analysis of cervical squamous cell carcinoma identifies potential protein biomarkers.

Cervical cancer remains a prevalent cancer among women, and reliance on surgical and radio-chemical therapies can irreversibly affect patients' life span and quality of life. Thus, early diagnosis and further exploration into the pathogenesis of cervical cancer are crucial. Mass spectrometry technology is widely applied in clinical practice and can be used to further investigate the protein alterations during the onset of cervical cancer. Employing labeled-free quantitative proteomics technology and bioinformatics tools, we analyzed and compared the differential protein expression profiles between normal cervical squamous cell tissues and cervical squamous cell cancer tissues. GEPIA is an online website for analyzing the RNA sequencing expression data of tumor and normal tissue data from the TCGA and the GTEx databases. This approach aided in identifying qualitative and quantitative changes in key proteins related to the progression of cervical cancer. Compared to normal samples, a total of 562 differentially expressed proteins were identified in cervical cancer samples, including 340 up-regulated and 222 down-regulated proteins. Gene ontology functional annotation, and KEGG pathway, and enrichment analysis revealed that the differentially expressed proteins mainly participated in metabolic pathways, spliceosomes, regulation of the actin cytoskeleton, and focal adhesion signaling pathways. Specifically, desmoplakin (DSP), protein phosphatase 1, regulatory (inhibitor) subunit 13 like (PPP1R13L) and ANXA8 may be involved in cervical tumorigenesis by inhibiting apoptotic signal transmission. Moreover, we used GEPIA database to validate the expression of DSP, PPP1R13L and ANXA8 in human cancers and normal cervix. In this study, we identified 562 differentially expressed proteins, and there were three proteins expressed higher in the cervical cancer tissues. The functions and signaling pathways of these differentially expressed proteins lay a theoretical foundation for elucidating the molecular mechanisms of cervical cancer.

Shared and distinguishing phenotypic characteristics of filamin c and desmoplakin cardiomyopathy

Abstract Background Rare truncating variants in the genes Filamin C (FLNC) and Desmoplakin (DSP) are increasingly recognised causes of Dilated Cardiomyopathy and Arrhythmogenic Cardiomyopathy (1,2). A direct comparison of both genotypes is needed to aid in subclassification and genotype-specific risk modelling. Purpose We sought to identify shared and distinguishing clinical characteristics and imaging phenotypes between FLNC and DSP cardiomyopathy. Methods 41 patients with ‘pathogenic’ or ‘likely pathogenic’ FLNC or DSP variants by American College of Medical Genetics (ACMG) criteria were identified from a tertiary centre cardiovascular genetics laboratory. Clinical, genetic and imaging data were compiled. Continuous variables are presented as median [IQR] or mean±SD and analysed by nonparametric Mann Whitney U or t-test. Categorical variables were analysed by Chi-Squared or Fisher’s exact test. Results FLNC and DSP cohorts included a similar proportion of patients with truncating variants (91% vs 100%) and female sex (12/21, 57% vs 13/20, 65%). FLNC patients were younger (median age 30 [13-51] vs 57 [41-65] years, p&amp;lt;0.0008) and more likely to present with sustained ventricular arrhythmia (5/21 24% vs 3/20, 15%) (Table 1). Acute myocarditis episodes were exclusively linked to DSP cardiomyopathy (4/20, 20%) with no association to FLNC (0/21, 0%, p&amp;lt;0.05). FLNC cardiomyopathy patients had normal left ventricular (LV) systolic function (LVEF 57±9% SD vs 46±13% DSP, p&amp;lt;0.03) and normal left ventricular cavity side (mean indexed LV end diastolic volume (EDV) 85±12 vs 112±26ml/m2 DSP, p&amp;lt;0.02) (Table 2). Both FLNC and DSP cause exclusive left ventricular or biventricular late gadolinium enhancement (75% Vs 82%) on cardiac magnetic resonance imaging (MRI). Fibrosis was predominantly in a subepicardial distribution in both cohorts (66% FLNC vs 57% DSP). In FLNC, circumferential fibrosis was the most frequent pattern of distribution (5/9, 55%), whereas in DSP inferior and lateral wall fibrosis was the predominant feature (8/14, 57%). There were no cases of isolated RV involvement and no cases fulfilled ‘definite’ ARVC taskforce diagnostic criteria. Over a follow up of median 45months, there was no significant difference in the proportion of FLNC and DSP patients experiencing a composite end point of LVAD implantation, heart transplant, aborted sudden cardiac death or mortality (7/21, 33% FLNC Vs 7/20, 29% DSP p&amp;gt;0.99). Conclusion Normal systolic function with marked circumferential fibrosis is the predominant feature of FLNC cardiomyopathy whereas mild LV dilatation, mild systolic impairment and inferolateral fibrosis are more frequent in DSP cardiomyopathy. Myocarditis episodes are a distinguishing feature of DSP cardiomyopathy, suggesting a different underlying molecular mechanism driven by inflammation. The overall clinical trajectory of FLNC and DSP cardiomyopathy patients are comparable.

Arrhythmic risk stratification in patients with left ventricular ring-like scar

Abstract Background Myocardial fibrosis assessment with late gadolinium enhancement (LGE) at cardiac magnetic resonance (CMR) has recently emerged as an independent predictor of major adverse events in patients with non-ischemic cardiomyopathy. Several studies have examined different locations and extension degrees of LGE, and the so called "ring-like pattern" has been related with an increased incidence of ventricular arrhythmias, in patients with dilated cardiomyopathy (DCM), but also in patients with preserved systolic function. Purpose To describe clinical, electrocardiographic, echocardiographic, CMR and genetic features of the left ventricular (LV) ring-like scar phenotype and to evaluate which characteristics may be associated with the risk of sudden cardiac death (SCD). Methods Patients diagnosed with LV ring-like scar were identified at 6 referral Centres. Diagnosis was based on: 1) ring-like LGE LV pattern, defined as at least 3 contiguous segments with subepicardial/midwall LGE in the same slice with or without fatty infiltration; or 2) pathology examination of explanted hearts/autoptic cases suffering from sudden cardiac death (SCD). Moreover, patients must have an additional inclusion criterion: a positive genetic test, or ≥1 patient in the same family with an ascertained cardiomyopathy. Major adverse arrhythmic cardiac events (MAACE), defined as a composite of SCD, aborted SCD, and sustained ventricular tachycardia (SVT), were the primary study endpoint. Results The final cohort comprised 129 patients (male 59.7%, median age at diagnosis 44 years). During a median follow-up of 3.4 years (IQR 1.2 – 64.), MAACE occurred in 31 patients (24%). Nearly 70% of the patients had a likely pathogenic/pathogenic mutation, mostly in desmoplakin (DSP) and filamin-C (FLNC) genes (65% and 19%, respectively). Sex, QRS width, and LGE in LV anterior wall and/or apex, were the only independent predictors of the outcome events (HR: 0.329, 95% CI: 0.119-0.916, P = 0.033; HR: 1.036, 95% CI 1.019-1.053, P &amp;lt; 0.001; HR 4.270, 95% CI 1.337-13.630, P = 0.014, respectively). A significant interaction between sex and LGE in anterior wall/apex was observed, being this regions associated with MAACE only in male patients (p for interaction = 0.033). Although related to the arrhythmic endpoint at the Kaplan-Meier survival curves, neither DCM echocardiographic phenotype, nor LV ejection fraction ≤35% remained statistically associated to MAACE at the multivariate analysis. Age, genetic mutations, right ventricular involvement, proband status, LV-LGE extension (number of segments) were not statistically related to the study endpoint. Conclusions In this selected cohort of patients with LV ring-like scar and either a genetic test or family history, malignant arrhythmic events were predicted by male sex, QRS width and LGE in anterior wall and/or apex.Graphical Abstract

Abstract 15846: Impaired Contraction and High Susceptibility to Arrhythmias in a Mouse Model of Desmoplakin-Mediated Arrhythmogenic Cardiomyopathy

Introduction: Desmoplakin (DSP) is a key protein for cardiac myocyte cell-to-cell adhesion that connects the desmosomes present in intercalated discs to the cytoplasmic network of desmin intermediate filaments. Pathogenic variants of the human DSP gene often lead to left ventricular (LV)-dominant and biventricular forms of arrhythmogenic cardiomyopathy characterized by a dilated LV, arrhythmias, and an elevated risk of sudden cardiac death. Nonetheless, the pathophysiological pathways triggered by DSP variants remain unknown. Hypothesis: We hypothesized that DSP pathogenic variants modify cardiomyocyte excitation-contraction coupling leading to life-threatening ventricular arrhythmias. Methods: We created a novel knock-in mouse model based on the human DSP p.S2859LfsX5 variant that leads to a murine protein truncated from its last 9 amino-acids. We compared one-year-old sedentary heterozygous (Dsp +/- ) animals to WT littermates and defined histologic, cellular, and molecular outcomes of the variant. Results: Western blotting revealed 50% Dsp reduction (N= 5 hearts/group; P &lt; 0.05) in mutant right ventricle (RV) indicating mutant protein instability. Histologic assessments of Dsp +/- hearts revealed LV chamber enlargement and RV wall thinning in the absence of fibrosis and lipid infiltration. Dsp +/- myocytes isolated from LV and RV free walls and field stimulated at 3 Hz exhibited 30-40% reduction in sarcomere shortening (n= 17-25 myocytes/ventricle/3-4 hearts/group; P &lt; 0.05), while their Ca 2+ handling properties remained normal. Pacing of Dsp +/- isolated myocytes (LV and RV) in the presence of (100 nmol/L) isoproterenol provoked a 20-30% increase in Ca 2+ release due to sarcoplasmic reticulum Ca 2+ overload (n= 15-20 myocytes/ventricle/3-4 hearts/group; P &lt; 0.05). Finally, surface ECGs showed that activation of the sympathetic pathway (isoproterenol + caffeine) in 6-month-old Dsp +/- mice increased mutant heart susceptibility to ventricular arrhythmias. Conclusions: The pathogenic variant p.S2859LfsX5 promotes biventricular dysfunction due to the loss in myocyte contraction capacity and catecholaminergic-mediated ventricular arrhythmias from cardiomyocyte Ca 2+ overload.

Abstract 17747: Gynecological Manifestations in a Patient With Arrhythmogenic Right Ventricular Cardiomyopathy: A Desmosomal Link?

Introduction: Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is inherited cardiomyopathy which is caused by desmosomal protein gene mutations, primarily in the desmoplakin (DSP), plakophilin-2 (PKP2), and desmoglein-2 (DSG2) genes. It is characterized pathologically by myocardial atrophy, fibrofatty replacement, and fibrosis, precipitating ventricular arrhythmias (VA). Desmosomal mutations have been linked to impaired follicular development and leiomyoma formation. However, there is little information about the association of their expression in myocardial with ovarian or uterine tissues. As incidences of ARVC/D in women increase, it is crucial to determine if women with the gynecological manifestations of these mutations are at a higher risk of developing ARCV/D. Case: We report a case of a 32-year-old female who presented with exercise-induced palpitations and syncopal episodes. She has a history of severe dysmenorrhea but has no medical conditions otherwise. On monitoring, she was found to have a high burden of ventricular premature complexes (VPCs). VAs were thought to have precipitated her syncopal episodes. She was started on antiarrhythmics. Echocardiogram demonstrated right ventricular dilatation and wall thinning. The patient later underwent genetic testing, which confirmed ARVC-associated mutations. Her dysmenorrhea was managed with combined oral contraceptives and nonsteroidal anti-inflammatory drugs. Pelvic ultrasound revealed leiomyomas, which were surgically removed. Discussion: This case supports the possible complex interplay between cardiovascular and gynecological conditions in patients with desmosomal mutations. Desmosomes are specialized protein complexes crucial in maintaining tissue's structural and mechanical stability. Mutations in desmosome genes disrupt the normal functioning of these protein complexes, leading to impaired cell-cell adhesion and increased vulnerability to tissue damage. The next step is to conduct studies to better understand the risk of developing cardiovascular disease in patients presenting with these gynecological conditions and vice versa to provide early monitoring and treatment.

Abstract 13631: Desmoplakin Cardiomyopathy in Pediatric Patients - A Distinct, Underrecognized Cohort of Arrhythmogenic Cardiomyopathy

Introduction: Arrhythmogenic cardiomyopathy is a spectrum of diagnoses including the historically recognized arrhythmogenic right ventricular cardiomyopathy. More recent literature describes predominately left ventricular (LV) or biventricular (BiV) involvement. Variants in the desmoplakin ( DSP) gene commonly cause LV and BiV phenotypes, though data in children are sparse. Hypothesis: Pediatric patients (pts) with DSP mutation have predominantly LV or BiV disease and may present with early onset malignant arrhythmia. Methods: We performed a multicenter, retrospective cohort study of pts &lt;21 years with pathogenic or likely pathogenic DSP variants from 6 tertiary referral children’s hospitals. We describe clinical variation in DSP probands (PBs), the first affected family member prompting genetic testing due to clinical history, as compared to genotype-positive family members (FMs) &lt;21 years of age diagnosed by familial cascade screening. Results: We identified 34 pts; 12 (35%) were PBs and 22 (65%) were FMs. Median age at genetic diagnosis was 13.3 and 12.3 years for PBs and FMs, respectively. Four PBs had LV-predominant disease; 6 had BiV disease (table 1). The most common initial diagnosis for PBs was myocarditis and dilated cardiomyopathy. ECG abnormalities were common in PBs (75%) and included left axis deviation, inferolateral T-wave inversion, and low QRS complex amplitude. The LV ejection fraction (EF) on echo was 48% and 65% for PBs and FMs, respectively. Eight PBs underwent MRI and 6 had late gadolinium enhancement involving the LV only, while 2 had BiV involvement. Six PBs underwent ICD implantation and 2 received appropriate ICD therapy (LVEF 25% and 41%). Two PBs had cardiac transplantation. Conclusion: Pediatric DSP -cardiomyopathy has predominantly LV or BiV involvement and may be misdiagnosed as myocarditis or dilated cardiomyopathy. Probands in particular, may present with early malignant ventricular arrhythmias and significant LV dysfunction.