Induced pluripotent stem cells (iPSCs) were first generated by Yamanaka and colleagues over a decade ago. Since then, iPSCs have been successfully differentiated into many distinct cell types, ...enabling tissue-, disease-, and patient-specific
modelling. Cardiovascular disease is the greatest cause of mortality worldwide but encompasses rarer disorders of conduction and myocardial function for which a cellular model of study is ideal. Although methods to differentiate iPSCs into beating cardiomyocytes (iPSC-CMs) have recently been adequately optimized and commercialized, the resulting cells remain largely immature with regards to their structure and function, demonstrating fetal gene expression, disorganized morphology, reliance on predominantly glycolytic metabolism and contractile characteristics that differ from those of adult cardiomyocytes. As such, disease modelling using iPSC-CMs may be inaccurate and of limited utility. However, this limitation is widely recognized, and numerous groups have made substantial progress in addressing this problem. This review highlights successful methods that have been developed for the maturation of human iPSC-CMs using small molecules, environmental manipulation and 3-dimensional (3D) growth approaches.
Anesthetics are deemed necessary for all major surgical procedures. However, they have also been found to exert neurotoxic effects when tested on various experimental models, but the underlying ...mechanisms remain unknown. Earlier studies have implicated mitochondrial fragmentation as a potential target of anesthetic-induced toxicity, although clinical strategies to protect their structure and function remain sparse. Here, we sought to determine if preserving mitochondrial networks with a non-toxic, short-life synthetic peptide-P110, would protect cortical neurons against both inhalational and intravenous anesthetic-induced neurotoxicity. This study provides the first direct and comparative account of three key anesthetics (desflurane, propofol, and ketamine) when used under identical conditions, and demonstrates their impact on neonatal, rat cortical neuronal viability, neurite outgrowth and synaptic assembly. Furthermore, we discovered that inhibiting Fis1-mediated mitochondrial fission reverses anesthetic-induced aberrations in an agent-specific manner. This study underscores the importance of designing mitigation strategies invoking mitochondria-mediated protection from anesthetic-induced toxicity in both animals and humans.
Full text
Available for:
IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Clozapine has superior efficacy in the treatment of refractory schizophrenia; however, use of clozapine is limited due to severe side effects, including myocarditis. Using non-integrative Sendai ...virus, we generated induced pluripotent stem cell lines from peripheral blood mononuclear cells of two patients with refractory schizophrenia, one clozapine-tolerant and one clozapine-induced myocarditis. Both cell lines exhibited a normal karyotype and pluripotency was validated by flow cytometry, immunofluorescence and their ability to differentiate into the three germ layers. These lines can be used to generate 2D and 3D patient-specific human cellular models to identify the mechanism by which clozapine induces myocardial inflammation.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We used patient dermal fibroblasts to characterize the mitochondrial abnormalities associated with the dilated cardiomyopathy with ataxia syndrome (DCMA) and to study the effect of the ...mitochondrially-targeted peptide SS-31 as a potential novel therapeutic. DCMA is a rare and understudied autosomal recessive disorder thought to be related to Barth syndrome but caused by mutations in
, a protein of unknown function localized to the mitochondria. The clinical disease is characterized by 3-methylglutaconic aciduria, dilated cardiomyopathy, abnormal neurological development, and other heterogeneous features. Until recently no effective therapies had been identified and affected patients frequently died in early childhood from intractable heart failure. Skin fibroblasts from four pediatric patients with DCMA were used to establish parameters of mitochondrial dysfunction. Mitochondrial structure, reactive oxygen species (ROS) production, cardiolipin composition, and gene expression were evaluated. Immunocytochemistry with semi-automated quantification of mitochondrial structural metrics and transmission electron microscopy demonstrated mitochondria to be highly fragmented in DCMA fibroblasts compared to healthy control cells. Live-cell imaging demonstrated significantly increased ROS production in patient cells. These abnormalities were reversed by treating DCMA fibroblasts with SS-31, a synthetic peptide that localizes to the inner mitochondrial membrane. Levels of cardiolipin were not significantly different between control and DCMA cells and were unaffected by SS-31 treatment. Our results demonstrate the abnormal mitochondria in fibroblasts from patients with DCMA and suggest that SS-31 may represent a potential therapy for this devastating disease.
Due to their ability to standardize key physiological parameters, stirred suspension bioreactors can potentially scale the production of quality-controlled pluripotent stem cells (PSCs) for cell ...therapy application. Because of differences in bioreactor expansion efficiency between mouse (m) and human (h) PSCs, we investigated if conversion of hPSCs, from the conventional "primed" pluripotent state towards the "naïve" state prevalent in mPSCs, could be used to enhance hPSC production. Through transcriptomic enrichment of mechano-sensing signaling, the expression of epigenetic regulators, metabolomics, and cell-surface protein marker analyses, we show that the stirred suspension bioreactor environment helps maintain a naïve-like pluripotent state. Our research corroborates that converting hPSCs towards a naïve state enhances hPSC manufacturing and indicates a potentially important role for the stirred suspension bioreactor's mechanical environment in maintaining naïve-like pluripotency.
Dilated cardiomyopathy with ataxia syndrome (DCMA) is an understudied autosomal recessive disease caused by loss-of-function mutations in the poorly characterized gene DNAJC19. Clinically, DCMA is ...commonly associated with heart failure and early death in affected children through an unknown mechanism. DCMA has been linked to Barth syndrome, a rare but well-studied disorder caused by deficient maturation of cardiolipin (CL), a key mitochondrial membrane phospholipid.
Peripheral blood mononuclear cells from 2 children with DCMA and severe cardiac dysfunction were reprogrammed into induced pluripotent stem cells (iPSCs). Patient and control iPSCs were differentiated into beating cardiomyocytes (iPSC-CMs) using a metabolic selection strategy. Mitochondrial structure and CL content before and after incubation with the mitochondrially targeted peptide SS-31 were quantified.
Patient iPSCs carry the causative DNAJC19 mutation (rs137854888) found in the Hutterite population, and the iPSC-CMs demonstrated highly fragmented and abnormally shaped mitochondria associated with an imbalanced isoform ratio of the mitochondrial protein OPA1, an important regulator of mitochondrial fusion. These abnormalities were reversible by incubation with SS-31 for 24 hours. Differentiation of iPSCs into iPSC-CMs increased the number of CL species observed, but consistent, significant differences in CL content were not seen between patients and control.
We describe a unique and novel cellular model that provides insight into the mitochondrial abnormalities present in DCMA and identifies SS-31 as a potential therapeutic for this devastating disease.
La cardiomyopathie dilatée avec ataxie (CMDA) est une maladie autosomale récessive peu étudiée, causée par des mutations perte de fonction dans le gène mal caractérisé DNAJC19. Sur le plan clinique, la CMDA est souvent associée, par un mécanisme inconnu, à l’insuffisance cardiaque et au décès prématuré chez les enfants qui en sont atteints. Un lien a en outre été établi entre la CMDA et le syndrome de Barth, une maladie rare mais bien connue causée par un défaut de maturation de la cardiolipine (CL), un phospholipide important de la membrane mitochondriale.
Des cellules mononuclées du sang périphérique prélevées chez deux enfants atteints de CMDA et d’une dysfonction cardiaque grave ont été reprogrammées en cellules souches pluripotentes induites (CSPi). Les CSPi des patients et des CSPi témoins ont ensuite été différenciées en cardiomyocytes battants (CSPi-CM) au moyen d’une stratégie de sélection métabolique. Enfin, la structure mitochondriale et la teneur en CL avant et après l’incubation en présence du peptide SS-31 ciblant les mitochondries ont été mesurées.
Les CSPi des patients sont porteuses de la mutation du gène DNAJC19 causale (rs137854888) qu’on trouve dans la population huttérite, et les CSPi-CM produites à partir de ces cellules présentaient des mitochondries très fragmentées et de forme anormale, qui sont associées à un rapport isoforme déséquilibré de la protéine mitochondriale OPA1, un important régulateur de la fusion mitochondriale. Ces anomalies ont pu être renversées après incubation en présence de peptide SS-31 pendant 24 heures. La différenciation des CSPi en CSPi-CM a augmenté le nombre d’espèces de CL observées, mais aucune différence constante ni significative de la teneur en CL n’a été relevée entre les cellules prélevées chez les patients et les cellules témoins.
Nous décrivons un modèle cellulaire unique et novateur qui permet de mieux comprendre les anomalies mitochondriales observées chez les patients atteints de CMDA et qui montre le potentiel thérapeutique du peptide SS-31 pour le traitement de cette maladie dévastatrice.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The dilated cardiomyopathy with ataxia syndrome (DCMA) is an autosomal recessive mitochondrial disease caused by mutations in the DnaJ heat shock protein family (Hsp40) member C19 (DNAJC19) gene. ...DCMA or 3‐methylglutaconic aciduria type V is globally rare, but the largest number of patients in the world is found in the Hutterite population of southern Alberta in Canada. We provide an update on phenotypic findings, natural history, pathological findings, and our clinical experience. We analyzed all available records for 43 patients diagnosed with DCMA between 2005 and 2015 at the Alberta Children's Hospital. All patients studied were Hutterite and homozygous for the causative DNAJC19 variant (c.130‐1G>C, IVS3‐1G>C) and had elevated levels of 3‐methyglutaconic acid. We calculated a birth prevalence of 1.54 cases per 1000 total births in the Hutterite community. Children were small for gestational age at birth and frequently required supplemental nutrition (63%) or surgical placement of a gastrostomy tube (35%). Early mortality in this cohort was high (40%) at a median age of 13 months (range 4‐294 months). Congenital anomalies were common as was dilated cardiomyopathy (50%), QT interval prolongation (83%), and developmental delay (95%). Tissue pathology was analyzed in a limited number of patients and demonstrated subendocardial fibrosis in the heart, macrovesicular steatosis and fibrosis in the liver, and structural abnormalities in mitochondria. This report provides clinical details for a cohort of children with DCMA and the first presentation of tissue pathology for this disorder. Despite sharing common genetic etiology and environment, the disease is highly heterogeneous for reasons that are not understood. DCMA is a clinically heterogeneous systemic mitochondrial disease with significant morbidity and mortality that is common in the Hutterite population of southern Alberta.
Full text
Available for:
FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
