Cardiac hypertrophic growth in response to pathological cues is associated with reexpression of fetal genes and decreased cardiac function and is often a precursor to heart failure. In contrast, ...physiologically induced hypertrophy is adaptive, resulting in improved cardiac function. The processes that selectively induce these hypertrophic states are poorly understood. Here, we have profiled 2 repressive epigenetic marks, H3K9me2 and H3K27me3, which are involved in stable cellular differentiation, specifically in cardiomyocytes from physiologically and pathologically hypertrophied rat hearts, and correlated these marks with their associated transcriptomes. This analysis revealed the pervasive loss of euchromatic H3K9me2 as a conserved feature of pathological hypertrophy that was associated with reexpression of fetal genes. In hypertrophy, H3K9me2 was reduced following a miR-217-mediated decrease in expression of the H3K9 dimethyltransferases EHMT1 and EHMT2 (EHMT1/2). miR-217-mediated, genetic, or pharmacological inactivation of EHMT1/2 was sufficient to promote pathological hypertrophy and fetal gene reexpression, while suppression of this pathway protected against pathological hypertrophy both in vitro and in mice. Thus, we have established a conserved mechanism involving a departure of the cardiomyocyte epigenome from its adult cellular identity to a reprogrammed state that is accompanied by reexpression of fetal genes and pathological hypertrophy. These results suggest that targeting miR-217 and EHMT1/2 to prevent H3K9 methylation loss is a viable therapeutic approach for the treatment of heart disease.
Myocardial Infarction (MI) is the most common cardiovascular disease. An average-sized MI causes the loss of up to 1 billion cardiomyocytes and the adult heart lacks the capacity to replace them. ...Although post-MI treatment has dramatically improved survival rates over the last few decades, more than 20% of patients affected by MI will subsequently develop heart failure (HF), an incurable condition where the contracting myocardium is transformed into an akinetic, fibrotic scar, unable to meet the body's need for blood supply. Excessive inflammation and persistent immune auto-reactivity have been suggested to contribute to post-MI tissue damage and exacerbate HF development. Two newly emerging fields of biomedical research, immunomodulatory therapies and cardiac bioengineering, provide potential options to target the causative mechanisms underlying HF development. Combining these two fields to develop biomaterials for delivery of immunomodulatory bioactive molecules holds great promise for HF therapy. Specifically, minimally invasive delivery of injectable hydrogels, loaded with bioactive factors with angiogenic, proliferative, anti-apoptotic and immunomodulatory functions, is a promising route for influencing the cascade of immune events post-MI, preventing adverse left ventricular remodeling, and offering protection from early inflammation to fibrosis. Here we provide an updated overview on the main injectable hydrogel systems and bioactive factors that have been tested in animal models with promising results and discuss the challenges to be addressed for accelerating the development of these novel therapeutic strategies.
Therapeutic advances for neurological disorders are challenging due to limited accessibility of the human central nervous system and incomplete understanding of disease mechanisms. Many neurological ...diseases lack precision treatments, leading to significant disease burden and poor outcome for affected patients. Induced pluripotent stem cell (iPSC) technology provides human neuronal cells that facilitate disease modeling and development of therapies. The use of genome editing, in particular CRISPR-Cas9 technology, has extended the potential of iPSCs, generating new models for a number of disorders, including Alzheimers and Parkinson Disease. Editing of iPSCs, in particular with CRISPR-Cas9, allows generation of isogenic pairs, which differ only in the disease-causing mutation and share the same genetic background, for assessment of phenotypic differences and downstream effects. Moreover, genome-wide CRISPR screens allow high-throughput interrogation for genetic modifiers in neuronal phenotypes, leading to discovery of novel pathways, and identification of new therapeutic targets. CRISPR-Cas9 has now evolved beyond altering gene expression. Indeed, fusion of a defective Cas9 (dCas9) nuclease with transcriptional repressors or activation domains allows down-regulation or activation of gene expression (CRISPR interference, CRISPRi; CRISPR activation, CRISPRa). These new tools will improve disease modeling and facilitate CRISPR and cell-based therapies, as seen for epilepsy and Duchenne muscular dystrophy. Genome engineering holds huge promise for the future understanding and treatment of neurological disorders, but there are numerous barriers to overcome. The synergy of iPSC-based model systems and gene editing will play a vital role in the route to precision medicine and the clinical translation of genome editing-based therapies.
The ability to manipulate cellular organization within soft materials has important potential in biomedicine and regenerative medicine; however, it often requires complex fabrication procedures. ...Here, a simple, cost‐effective, and one‐step approach that enables the control of cell orientation within 3D collagen hydrogels is developed to dynamically create various tailored microstructures of cardiac tissues. This is achieved by incorporating iron oxide nanoparticles into human cardiomyocytes and applying a short‐term external magnetic field to orient the cells along the applied field to impart different shapes without any mechanical support. The patterned constructs are viable and functional, can be detected by T2*‐weighted magnetic resonance imaging, and induce no alteration to normal cardiac function after grafting onto rat hearts. This strategy paves the way to creating customized, macroscale, 3D tissue constructs with various cell‐types for therapeutic and bioengineering applications, as well as providing powerful models for investigating tissue behavior.
Dynamic magnetic patterning of cells within 3D hydrogels is successfully developed by manipulating magnetoresponsive cardiomyocytes to a desired orientation under the influence of external magnetic fields. The constructs are viable and functional and can be identified noninvasively by magnetic resonance imaging. The simplicity, high reproducibility, and improved robustness that this method offers provide a new platform to engineer organized and complex tissues.
Increasingly effective targeted precision medicine is either already available or in development for a number of genetic childhood movement disorders. Patient‐centred, personalized approaches include ...the repurposing of existing treatments for specific conditions and the development of novel therapies that target the underlying genetic defect or disease mechanism. In tandem with these scientific advances, close collaboration between clinicians, researchers, affected families, and stakeholders in the wider community will be key to successfully delivering such precision therapies to children with movement disorders.
What this paper adds
Precision medicine for genetic childhood movement disorders is developing rapidly.
Accurate diagnosis, disease‐specific outcome measures, and collaborative multidisciplinary work will accelerate the progress of such strategies.
What this paper adds
Precision medicine for genetic childhood movement disorders is developing rapidly.
Accurate diagnosis, disease‐specific outcome measures, and collaborative multidisciplinary work will accelerate the progress of such strategies.
Extracellular vesicles (EVs) represent a promising cell-free alternative for treatment of cardiovascular diseases. Nevertheless, the lack of standardised and reproducible isolation methods capable of ...recovering pure, intact EVs presents a significant obstacle. Additionally, there is significant interest in investigating the interactions of EVs with different cardiac cell types. Here we established a robust technique for the production and isolation of EVs harvested from an enriched (>97% purity) population of human induced pluripotent stem cell (iPSC)-derived cardiomyocytes (CMs) with size exclusion chromatography. Utilizing an advanced fluorescence labelling strategy, we then investigated the interplay of the CM-EVs with the three major cellular components of the myocardium (fibroblasts, cardiomyocytes and endothelial cells) and identified that cardiac endothelial cells show preferential uptake of these EVs. Overall, our findings provide a great opportunity to overcome the translational hurdles associated with the isolation of intact, non-aggregated human iPSC-CM EVs at high purity. Furthermore, understanding in detail the interaction of the secreted EVs with their surrounding cells in the heart may open promising new avenues in the field of EV engineering for targeted delivery in cardiac regeneration.
Highly purified EVs isolated from human cardiomyocytes show differential uptake in cardiac cell types.
Clinical experience with the impact of serum biomarkers for invasive fungal disease (IFD) varies markedly in hemato-oncology. Invasive pulmonary aspergillosis (IPA) is the most common manifestation, ...so we evaluated biomarkers in bronchoalveolar lavage (BAL) fluid. An Aspergillus-specific lateral-flow device (LFD), quantitative real-time PCR (qPCR), and the galactomannan (GM) test were used with 32 BAL fluid samples from 32 patients at risk of IPA. Eight patients had proven IPA, 3 had probable IPA, 6 had possible IPA, and 15 patients had no IPA by European Organization for Research and Treatment of Cancer Invasive Fungal Infections Cooperative Group/Mycoses Study Group of the National Institute of Allergy and Infectious Diseases (EORTC/MSG) criteria. The diagnostic accuracies of the tests were evaluated, and pairwise agreement between biomarkers was calculated. The diagnostic performance of the EORTC/MSG criteria was evaluated against the test(s) identified to be the most useful for IPA diagnosis. Using the EORTC/MSG criteria, the sensitivities of qPCR and LFD were 100% and the sensitivity of the GM test was 87.5% (GM test index cutoff, >0.8), with the tests having specificities of between 66.7 and 86.7%. The agreement between the results of qPCR and LFD was almost perfect (Cohen's kappa coefficient = 0.93, 95% confidence interval, 0.81 to 1.00). LFD and qPCR combined had a sensitivity of 100% and a specificity of 85.7%. Calcofluor staining and culture of all BAL fluid samples were negative for fungal infection. The median time from the start of mold-active antifungal therapy to the time of collection of BAL fluid was 6 days. Reversing roles and using dual testing by LFD and qPCR to classify cases, the EORTC/MSG criteria had a sensitivity of 83.3%. All three tests are useful for the diagnosis of IPA in BAL fluid samples. Despite the significant delays between the start of antifungal therapy and bronchoscopy, unlike microscopy and culture, the biomarkers remained informative. In particular, the combination of LFD and qPCR allows the sensitive and specific detection of IPA.
The incidence of invasive aspergillosis (IA), an opportunistic infection in immunocompromised individuals, is rising, but its early diagnosis remains challenging and treatment options are limited. ...Hence there is an urgent need to improve existing diagnostic procedures as well as develop novel approaches. The clinical usefulness of galactomannan and β-d-glucan, widely used assays detecting cell-wall antigens of Aspergillus, is unclear and depends on clinicians' awareness of their practical limitations. This leaves room for new methods that utilise genomic, proteomic and metabolomics approaches as well as novel detection procedures, for example point-of-care lateral-flow devices. Each of these strategies has its own limitations and it is likely that a combination of methods will be required to achieve optimal performance for the diagnosis of IA and subsequent appropriate patient management.
Objectives: The majority of people with suspected genetic dystonia remain undiagnosed after maximal investigation, implying that a number of causative genes have not yet been recognized. We aimed to ...investigate this paucity of diagnoses. Methods We undertook weighted burden analysis of whole-exome sequencing (WES) data from 138 individuals with unresolved generalized dystonia of suspected genetic etiology, followed by additional case-finding from international databases, first for the gene implicated by the burden analysis (VPS16), and then for other functionally related genes. Electron microscopy was performed on patient-derived cells. Results Analysis revealed a significant burden forVPS16(Fisher's exact testpvalue, 6.9 x 10(9)).VPS16encodes a subunit of the homotypic fusion and vacuole protein sorting (HOPS) complex, which plays a key role in autophagosome-lysosome fusion. A total of 18 individuals harboring heterozygous loss-of-functionVPS16variants, and one with a microdeletion, were identified. These individuals experienced early onset progressive dystonia with predominant cervical, bulbar, orofacial, and upper limb involvement. Some patients had a more complex phenotype with additional neuropsychiatric and/or developmental comorbidities. We also identified biallelic loss-of-function variants inVPS41, another HOPS-complex encoding gene, in an individual with infantile-onset generalized dystonia. Electron microscopy of patient-derived lymphocytes and fibroblasts from both patients withVPS16andVPS41showed vacuolar abnormalities suggestive of impaired lysosomal function. Interpretation Our study strongly supports a role for HOPS complex dysfunction in the pathogenesis of dystonia, although variants in different subunits display different phenotypic and inheritance characteristics. ANN NEUROL 2020
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