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Communications Medicine Mar 2024Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a familial cardiac disease associated with ventricular arrhythmias and an increased risk of sudden cardiac...
BACKGROUND
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a familial cardiac disease associated with ventricular arrhythmias and an increased risk of sudden cardiac death. Currently, there are no approved treatments that address the underlying genetic cause of this disease, representing a significant unmet need. Mutations in Plakophilin-2 (PKP2), encoding a desmosomal protein, account for approximately 40% of ARVC cases and result in reduced gene expression.
METHODS
Our goal is to examine the feasibility and the efficacy of adeno-associated virus 9 (AAV9)-mediated restoration of PKP2 expression in a cardiac specific knock-out mouse model of Pkp2.
RESULTS
We show that a single dose of AAV9:PKP2 gene delivery prevents disease development before the onset of cardiomyopathy and attenuates disease progression after overt cardiomyopathy. Restoration of PKP2 expression leads to a significant extension of lifespan by restoring cellular structures of desmosomes and gap junctions, preventing or halting decline in left ventricular ejection fraction, preventing or reversing dilation of the right ventricle, ameliorating ventricular arrhythmia event frequency and severity, and preventing adverse fibrotic remodeling. RNA sequencing analyses show that restoration of PKP2 expression leads to highly coordinated and durable correction of PKP2-associated transcriptional networks beyond desmosomes, revealing a broad spectrum of biological perturbances behind ARVC disease etiology.
CONCLUSIONS
We identify fundamental mechanisms of PKP2-associated ARVC beyond disruption of desmosome function. The observed PKP2 dose-function relationship indicates that cardiac-selective AAV9:PKP2 gene therapy may be a promising therapeutic approach to treat ARVC patients with PKP2 mutations.
PubMed: 38499690
DOI: 10.1038/s43856-024-00450-w -
Materials Today. Bio Apr 2024In this study, we explore the impact of mechanical stimuli on skin models using an innovative skin-on-a-chip platform, addressing the limitations of conventional...
In this study, we explore the impact of mechanical stimuli on skin models using an innovative skin-on-a-chip platform, addressing the limitations of conventional transwell-cultured skin equivalents. This platform facilitates cyclic mechanical stimulation through compression and stretching, combined with automated media perfusion. Our findings, using bioimaging and bulk RNA sequencing, reveal increased expression of Keratin 10 and Keratin 14, indicating enhanced skin differentiation and mechanical integrity. The increase in desmosomes and tight junctions, observed through Claudin-1 and Desmoplakin 1 & 2 analysis, suggests improved keratinocyte differentiation due to mechanical stimulation. Gene expression analyses reveal a nuanced regulatory response, suggesting a potential connection to the Hippo pathway, indicative of a significant cellular reaction to mechanical stimuli. The results show the important influence of mechanical stimulation on skin model integrity and differentiation, demonstrating the potential of our microfluidic platform in advancing skin biology research and pharmaceutical testing.
PubMed: 38495916
DOI: 10.1016/j.mtbio.2024.101010 -
European Heart Journal. Case Reports Mar 2024Arrhythmogenic ventricular cardiomyopathy (AVC) is a hereditary cardiomyopathy that has been associated with mutations in genes encoding for components of the cardiac...
BACKGROUND
Arrhythmogenic ventricular cardiomyopathy (AVC) is a hereditary cardiomyopathy that has been associated with mutations in genes encoding for components of the cardiac desmosome including desmoglein-2 (DSG-2).
CASE SUMMARY
A 49-year-old male presented with decompensated heart failure and ventricular arrythmias. A cardiac magnetic resonance scan demonstrated a dilated left ventricle (LV) with severely impaired systolic function and extensive subepicardial late gadolinium enhancement in the lateral wall. An 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) scan identified myocardial uptake consistent with inflammation. Following treatment with steroids for presumed cardiac sarcoidosis, a repeat FDG-PET confirmed resolution of inflammation. A dilated cardiomyopathy/AVC gene panel, however, subsequently identified a pathogenic variant in the DSG-2 gene.
DISCUSSION
We describe the case of a patient presenting with clinical and imaging features suggestive for cardiac sarcoidosis, however genetic testing established a diagnosis of DSG-2 associated AVC. DSG-2 mutations in AVC are associated with frequent LV involvement and heart failure. Active inflammation has been observed in other cardiomyopathies, specifically in desmoplakin cardiomyopathy which has a similar clinical course to DSG-2. To our knowledge, this is the first case of DSG-2 cardiomyopathy presenting in this manner. We encourage clinicians to have a high index of suspicion of inflammatory cardiomyopathies as a differential to myocarditis and cardiac sarcoidosis, when patients present with evidence of decompensated heart failure, arrhythmias, and active myocardial inflammation.
PubMed: 38481604
DOI: 10.1093/ehjcr/ytae107 -
APL Bioengineering Mar 2024Engineered heart tissues have been created to study cardiac biology and disease in a setting that more closely mimics heart muscle than 2D monolayer culture. Previously...
Engineered heart tissues have been created to study cardiac biology and disease in a setting that more closely mimics heart muscle than 2D monolayer culture. Previously published studies suggest that geometrically anisotropic micro-environments are crucial for inducing " like" physiology from immature cardiomyocytes. We hypothesized that the degree of cardiomyocyte alignment and prestress within engineered tissues is regulated by tissue geometry and, subsequently, drives electrophysiological development. Thus, we studied the effects of tissue geometry on electrophysiology of micro-heart muscle arrays (HM) engineered from human induced pluripotent stem cells (iPSCs). Elongated tissue geometries elicited cardiomyocyte shape and electrophysiology changes led to adaptations that yielded increased calcium intake during each contraction cycle. Strikingly, pharmacologic studies revealed that a threshold of prestress and/or cellular alignment is required for sodium channel function, whereas L-type calcium and rapidly rectifying potassium channels were largely insensitive to these changes. Concurrently, tissue elongation upregulated sodium channel (Na1.5) and gap junction (Connexin 43, Cx43) protein expression. Based on these observations, we leveraged elongated HM to study the impact of loss-of-function mutation in Plakophilin 2 (PKP2), a desmosome protein implicated in arrhythmogenic disease. Within HM, PKP2 knockout cardiomyocytes had cellular morphology similar to what was observed in isogenic controls. However, PKP2 tissues exhibited lower conduction velocity and no functional sodium current. PKP2 knockout HM exhibited geometrically linked upregulation of sodium channel but not Cx43, suggesting that post-translational mechanisms, including a lack of ion channel-gap junction communication, may underlie the lower conduction velocity observed in tissues harboring this genetic defect. Altogether, these observations demonstrate that simple, scalable micro-tissue systems can provide the physiologic stresses necessary to induce electrical remodeling of iPS-CM to enable studies on the electrophysiologic consequences of disease-associated genomic variants.
PubMed: 38476404
DOI: 10.1063/5.0160677 -
JACC. Advances Feb 2024Thousands of genetic variants have been identified in cardiomyopathy-associated genes. Diagnostic genetic testing is key for evaluation of individuals with suspected...
BACKGROUND
Thousands of genetic variants have been identified in cardiomyopathy-associated genes. Diagnostic genetic testing is key for evaluation of individuals with suspected cardiomyopathy. While accurate variant pathogenicity assignment is important for diagnosis, the frequency of and factors associated with clinically relevant assessment changes are unclear.
OBJECTIVES
The authors aimed to characterize pathogenicity assignment change in cardiomyopathy-associated genes and to identify factors associated with this change.
METHODS
We identified 10 sarcomeric and 6 desmosomal genetic cardiomyopathy-associated genes along with comparison gene sets. We analyzed clinically meaningful changes in pathogenicity assignment between any of the following: pathogenic/likely pathogenic (P/LP), conflicting interpretations of pathogenicity or variant of unknown significance (C/VUS), and benign/likely benign. We explored association of minor allele frequency (MAF) differences between well, and traditionally poorly, represented ancestries in genetic studies with assessment stability. Analyses were performed using ClinVar and GnomAD data.
RESULTS
Of the 30,975 cardiomyopathy-associated gene variants in ClinVar, 2,276 of them (7.3%) had a clinically meaningful change in pathogenicity assignment over the study period, 2011 to 2021. Sixty-seven percent of variants that underwent a clinically significant change moved from P/LP or benign/likely benign to C/VUS. Among cardiomyopathy variants downgraded from P/LP, 35% had a MAF above 1 × 10 in non-Europeans and below 1 × 10 in Europeans.
CONCLUSIONS
Over the past 10 years, 7.3% of cardiomyopathy gene variants underwent a clinically meaningful change in pathogenicity assignment. Over 30% of downgrades from P/LP may be attributable to higher MAF in Non-Europeans than Europeans. This finding suggests that low ancestral diversity in genetic studies has increased diagnostic uncertainty in cardiomyopathy gene variants.
PubMed: 38464909
DOI: 10.1016/j.jacadv.2023.100767 -
BioRxiv : the Preprint Server For... Feb 2024Previous studies have implicated persistent innate immune signaling in the pathogenesis of arrhythmogenic cardiomyopathy (ACM), a familial non-ischemic heart muscle...
Previous studies have implicated persistent innate immune signaling in the pathogenesis of arrhythmogenic cardiomyopathy (ACM), a familial non-ischemic heart muscle disease characterized by life-threatening arrhythmias and progressive myocardial injury. Here, we provide new evidence implicating inflammatory lipid autocoids in ACM. We show that specialized pro-resolving lipid mediators are reduced in hearts of mice, a well characterized mouse model of ACM. We also found that ACM disease features can be reversed in rat ventricular myocytes expressing mutant by the pro-resolving epoxy fatty acid (EpFA) 14,15-eicosatrienoic acid (14-15-EET), whereas 14,15-EE-5(Z)E which antagonizes actions of the putative 14,15-EET receptor, intensified nuclear accumulation of the desmosomal protein plakoglobin. Soluble epoxide hydrolase (sEH), an enzyme that rapidly converts pro-resolving EpFAs into polar, far less active or even pro-inflammatory diols, is highly expressed in cardiac myocytes in mice. Inhibition of sEH prevented progression of myocardial injury in mice and led to recovery of contractile function. This was associated with reduced myocardial expression of genes involved in the innate immune response and fewer pro-inflammatory macrophages expressing CCR2, which mediate myocardial injury in mice. These results suggest that pro-inflammatory eicosanoids contribute to the pathogenesis of ACM and, further, that inhibition of sEH may be an effective, mechanism-based therapy for ACM patients.
PubMed: 38463975
DOI: 10.1101/2024.02.17.580812 -
Dermatology and Therapy Mar 2024Vulvar lichen sclerosus (VLS) is a chronic inflammatory condition affecting the anogenital region, which can manifest in prepubertal or adolescent patients. The...
INTRODUCTION
Vulvar lichen sclerosus (VLS) is a chronic inflammatory condition affecting the anogenital region, which can manifest in prepubertal or adolescent patients. The prevailing theories point to autoimmune and genetic factors. The primary symptoms of VLS typically include vulvar itching, discomfort, dysuria, and constipation. Physical examination often reveals a characteristic figure 8 pattern, involving the labia minora, clitoral hood, and perianal region. However, these symptoms and the age of onset are nonspecific and require differentiation from autoimmune dermatoses such as bullous diseases, pemphigus diseases, epidermolysis bullosa acquisita, and dermatitis herpetiformis. We performed this study to distinguish VLS from autoimmune dermatoses, and in doing so, uncover the underlying causes of chronic vulvar changes. This knowledge will enable healthcare providers to offer appropriate medical care to affected patients.
METHODS
The study was conducted between July 2020 and February 2021, with a sample of 55 girls aged 2-18 years who did not have any systemic diseases. The study group was composed of 20 girls previously diagnosed with vulvar lichen sclerosus, while the control group included 35 girls without VLS. Questionnaires regarding the medical history of the children were completed by their legal guardians. Blood samples were collected and analyzed biochemically to assess human immunoglobulin A (IgA), IgG, and IgM antibodies against various substrates, including the desmosome of stratum spinosum, basement membrane zone, desmoglein 1 (DSG1), desmoglein 3 (DSG3), BP180-NC16A-4X, BP230gC, pemphigoid antigen, collagen type VII NC1, transitional epithelium, gliadin (GAF-3X), endomysium (EMA), and cellular nucleus (ANA).
RESULTS
The analysis of the study group revealed that the most commonly observed signs and symptoms included: itching, soreness, burning sensations, and excoriation, as well as erythema or/and pallor of the skin and perineal mucosa. Among the assessed antibodies, only anti-GAF3x antibodies and ANA antibodies were detected. However, the results did not reach statistical significance (p > 0.5).
PubMed: 38451422
DOI: 10.1007/s13555-024-01124-0 -
Seminars in Immunopathology Jan 2024The lungs serve as the primary organ for respiration, facilitating the vital exchange of gases with the bloodstream. Given their perpetual exposure to external... (Review)
Review
The lungs serve as the primary organ for respiration, facilitating the vital exchange of gases with the bloodstream. Given their perpetual exposure to external particulates and pathogens, they possess intricate protective barriers. Cellular adhesion in the lungs is robustly maintained through tight junctions, adherens junctions, and desmosomes. Furthermore, the pulmonary system features a mucociliary clearance mechanism that synthesizes mucus and transports it to the outside. This mucus is enriched with chemical barriers like antimicrobial proteins and immunoglobulin A (IgA). Additionally, a complex immunological network comprising epithelial cells, neural cells, and immune cells plays a pivotal role in pulmonary defense. A comprehensive understanding of these protective systems offers valuable insights into potential pathologies and their therapeutic interventions.
Topics: Humans; Lung; Animals; Mucociliary Clearance; Respiratory Mucosa; Tight Junctions; Cell Adhesion; Mucus
PubMed: 38451292
DOI: 10.1007/s00281-024-01003-y -
Journal of Voice : Official Journal of... Feb 2024To develop a novel Laryngopharyngeal Reflux Disease (LPRD) model in Bama pigs through endoscopic cricopharyngeal myotomy.
OBJECTIVE
To develop a novel Laryngopharyngeal Reflux Disease (LPRD) model in Bama pigs through endoscopic cricopharyngeal myotomy.
METHODS
A total of eight 8-month-old Bama pigs were randomly assigned to either the control or surgery group. Prior to intervention, upper esophageal sphincter (UES) manometry and laryngopharyngeal Dx-pH monitoring were conducted to establish baseline physiological parameters for each pig. Subsequently, the surgery group underwent endoscopic cricopharyngeal myotomy, while the control group did not. Two weeks postintervention, these procedures were repeated to evaluate changes in UES contractility and the occurrence of reflux events. At week eight postsurgery, mucosal tissues from both groups were harvested for histological analysis. Hematoxylin and eosin (H&E) staining was used to assess inflammation, while transmission electron microscopy (TEM) examined alterations in intercellular spaces and desmosomes.
RESULTS
The mean UES pressures in the control and surgery groups were 59 ± 9 mmHg and 68 ± 12 mmHg, respectively. In the surgery group, there was a significant decrease in UES pressure 2weeks after the operation compared to preoperative values (P = 0.005), whereas no significant change was observed in the control group (P = 0.488). Laryngopharyngeal reflux (LPR) was successfully induced in the surgery group as evidenced by reflux events with pH <5.0, which were not detected in the control group. HE staining revealed marked inflammatory cell infiltration and submucosal gland expansion in throat tissues of the surgery group Bama pigs. TEM further showed enlarged intercellular spaces and reduced desmosome numbers in the laryngopharyngeal epithelium compared to controls.
CONCLUSION
Given analogous throat epithelial structures to humans, Bama pigs are an appropriate species for an LPRD animal model. Endoscopic cricopharyngeal myotomy effectively induces LPR and observable pathological changes in Bama pigs, providing a valuable platform for further research into LPRD pathophysiology.
PubMed: 38429118
DOI: 10.1016/j.jvoice.2024.02.001 -
Kidney International May 2024Desmosomes are multi-protein cell-cell adhesion structures supporting cell stability and mechanical stress resilience of tissues, best described in skin and heart. The...
Desmosomes are multi-protein cell-cell adhesion structures supporting cell stability and mechanical stress resilience of tissues, best described in skin and heart. The kidney is exposed to various mechanical stimuli and stress, yet little is known about kidney desmosomes. In healthy kidneys, we found desmosomal proteins located at the apical-junctional complex in tubular epithelial cells. In four different animal models and patient biopsies with various kidney diseases, desmosomal components were significantly upregulated and partly miss-localized outside of the apical-junctional complexes along the whole lateral tubular epithelial cell membrane. The most upregulated component was desmoglein-2 (Dsg2). Mice with constitutive tubular epithelial cell-specific deletion of Dsg2 developed normally, and other desmosomal components were not altered in these mice. When challenged with different types of tubular epithelial cell injury (unilateral ureteral obstruction, ischemia-reperfusion, and 2,8-dihydroxyadenine crystal nephropathy), we found increased tubular epithelial cell apoptosis, proliferation, tubular atrophy, and inflammation compared to wild-type mice in all models and time points. In vitro, silencing DSG2 via siRNA weakened cell-cell adhesion in HK-2 cells and increased cell death. Thus, our data show a prominent upregulation of desmosomal components in tubular cells across species and diseases and suggest a protective role of Dsg2 against various injurious stimuli.
Topics: Animals; Humans; Mice; Cell Adhesion; Desmoglein 2; Desmosomes; Heart; Kidney Diseases
PubMed: 38395410
DOI: 10.1016/j.kint.2024.01.037