A negative screen for mutations in calstabin 1 and 2 genes in patients with dilated cardiomyopathy

<p>Abstract</p> <p>Background</p> <p>Calstabins 1 and 2 bind to Ryanodine receptors regulating muscle excitation-contraction coupling. Mutations in Ryanodine receptors affecting their interaction with calstabins lead to different cardiac pathologies. Animal studies suggest the involvement of calstabins with dilated cardiomyopathy.</p> <p>Results</p> <p>We tested the hypothesis that calstabins mutations may cause dilated cardiomyopathy in humans screening 186 patients with idiopathic dilated cardiomyopathy for genetic alterations in calstabins 1 and 2 genes (<it>FKBP12 </it>and <it>FKBP12.6)</it>. No missense variant was found. Five no-coding variations were found but not related to the disease.</p> <p>Conclusions</p> <p>These data corroborate other studies suggesting that mutations in <it>FKBP12 </it>and <it>FKBP12.6 </it>genes are not commonly related to cardiac diseases.</p

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Induced pluripotent stem cells to study cardiomyocytes derived from patients with genetic cardiomyopathies

O estudo de mutações genéticas como causa das cardiomiopatias teve início com a descoberta de mutações em proteínas sarcoméricas que levavam à Cardiomiopatia Hipertrófica, desde então, alterações em diversos genes, de proteínas contráteis ou não, foram descobertas e listadas como a responsável pelo desenvolvimento de diferentes cardiomiopatias. Estudar o efeito destas mutações nos cardiomiócitos destes pacientes permanecia um desafio devido ao difícil acesso às células cardíacas. Em 2007, a técnica de reprogramação de células somáticas em células-tronco pluripotentes foi descoberta. Pelo fato das células-tronco pluripotentes serem capazes de ser diferenciadas em cardiomiócitos, surgiu-se a possibilidade de se estudar essas células de indivíduos portadores das mutações genéticas. Esta tese teve como objetivo a criação de um modelo celular para estudar a Cardiomiopatia Hipertrófica causada por mutações genéticas. Inicialmente foi estabelecido um protocolo de reprogramação celular para se estabelecer linhagens celulares das células-tronco induzidas de um paciente com mutação no gene MYH7. Tendo as células caracterizadas, elas foram diferenciadas em cardiomiócitos através de um protocolo adaptado de protocolos de diferenciação direta em cardiomiócitos. Os cardiomiócitos gerados apresentaram características moleculares e funcionais semelhantes à cardiomiócitos primários humanos e foi visualizado, através de microscopia eletrônica de transmissão, que os cardiomiócitos do paciente com alteração genética possuíam grande proporção de sarcômeros desorganizados em comparação a cardiomiócitos de indivíduos saudáveis. Em conclusão, o modelo celular desenvolvido sugere ser possível o estudo do efeito de mutações genéticas em Cardiomiopatia Hipertrófica.The study of genetic mutations as the cause of cardiomyopathies initiates with the discovery of mutations in sarcomeric proteins genes that lead to Hypertrophic Cardiomyopathy. Since then, mutations in several genes, coding to sarcomeric proteins or not, were discovered and listed as the reason to the cardiomyopathies. To study the effect of these mutations was a challenge due the difficulty to accesses cardiac cells. In 2007, the technique of reprogramming somatic cells into pluripotent stem cells was discovered. The fact that the pluripotent stem cells are capable of differentiating into cardiomyocytes opened the opportunity to study these cells from individuals with genetic mutations. This thesis aimed to create a cellular model to study Hypertrophic Cardiomyopathy caused by genetic mutations. Initially we established a cell reprogramming protocol to establish induced stem cells lines from a patient with mutation in MYH7 gene. Having characterized the cells, they were differentiated into cardiomyocytes using an adapted protocol from direct differentiation protocols. Cardiomyocytes generated showed molecular and functional characteristics similar to human primary cardiomyocytes and were visualized by means of transmission electron microscopy. The patient\'s cardiomyocytes had a large proportion of disorganized sarcomeres compared to cardiomyocytes from healthy individuals. In conclusion, the cell model developed suggests that it is possible to study the effect of genetic mutation in Hypertrophic Cardiomyopathy using induced pluripotent stem cells derived cardiomyocytes

Genetic screening in dilated cardiomyopathy patients

Introdução: A cardiomiopatia dilatada é uma das principais causas de insuficiência cardíaca com alta morbidade e mortalidade. Alterações genéticas em mais de 29 genes já foram relacionadas com a doença, contudo, elas explicam apenas uma pequena porcentagem dos casos sugerindo haver então outros genes relacionados com a doença. Foram relacionados para o presente projeto quatro genes candidatos, previamente relacionados com outras doenças cardíacas, para verificação de uma possível associação com a cardiomiopatia dilata idiopática. Objetivos: Avaliar a presença e frequência de mutações nos genes ACTC1, CSRP3, FKBP1A e FKBP1B de pacientes com cardiomiopatia dilatada do Instituto do Coração de São Paulo (InCor, FMUSP), investigar se há correlações entre o genótipo e o fenótipo e estudar as alterações funcionais desencadeadas pelas mutações encontradas. Métodos: Amostras de DNA de 186 pacientes com cardiomiopatia dilatada idiopática foram selecionados de um banco de dados do Instituto do Coração e triados geneticamente para alterações nos genes selecionados. Resultados e Discussão: Foram encontradas nove novas variantes genéticas. Cinco delas também estavam presentes no grupo controle, sendo excluídas como causativas da doença. Três delas não estavam presentes no grupo controle, contudo, dados de bioinformática avaliaram as alterações com um risco baixo de serem causativas. Uma alteração no gene CSRP3, que levava a troca de aminoácido, não estava presente no grupo controle e apresentou dados indicativos de mutação causativa da doença. Lâminas cardíacas foram avaliadas para verificação de possíveis dos mecanismos de ação, contudo, houve apenas a exclusão de alguns mecanismos previamente descritos na literatura. Conclusões: Não há evidências de que as alterações nos genes ACTC1, FKBP1A e FKBP1B estariam associadas com o desenvolvimento da doença. A alteração no gene CSRP3 também é capaz de causar cardiomiopatia dilatada idiopáticaIntroduction: Dilated Cardiomyopathy is one of the leading causes of heart failure with high morbidity e mortality. Already known genetic alterations explain little percentage of cases suggesting that other genes would be related with the disease. Four candidates genes previously related with other cardiac diseases were selected for the project to verify a possible relationship with dilated cardiomyopathy. Objectives: Evaluate the presence and frequency of genetic alterations in ACTC1, FKBP1A, FKBP1B and CSRP3 genes in dilated cardiomyopathy patients of São Paulo Heart Institute (Incor, FMUSP). To investigate for genotype/phenotype correlations and to study functional alterations triggered by the found mutations. Methods: DNA samples from 186 patients with dilated cardiomyopathy were selected from the Incor DNA bank and genetically screened for alterations in the selected genes. Results and Discussion: Nine new genetic variants were found. Five of them were present in the control population, thus being excluded as disease causative. Three of them were not present in the control population; however, bioinformatics analysis evaluated the alterations having a low risk of being causatives. One alteration in CSRP3 gene that resulted in amino-acid change was not present in control population and exhibit indicative data of disease causing mutation. Analysis of patient heart showed no difference from some disease mechanisms described in literature. Conclusions: There are no evidences that alterations in ACTC1, FKBP1A and FKBP1B genes would associated with disease development. Alteration in CSRP3 gene is also capable to cause dilated cardiomyopathy

Human cardiomyocytes for drug discovery

Introduction: Cardiac drug discovery are based in old methods that use animals, animal cells or modified cells that do not faithfully represent human cardiac phenotypes. Objective: Here, we aimed to show that cardiomyocytes derived from human iPS cells represent a new tool for cardiac drug discovery and could contribute do reduce animal use in research. Method: Generation of human iPS cells derived  cardiomyocytes and its use for cardiotoxicity evaluation and infection with T. cruzi for drug discovery. Results: Definition of robust protocol for human iPS cells reprogramming, maintenance and cardiac differentiation. Derivation of high purity cardiomyocytes from hiPSCs that presented toxicity to different doses of doxorubicin and were amenable to infection of T. cruzi. Conclusions: Human cardiomyocytes derived from human iPS cells can be a great tool for drug discovery and can replace several assays done in animals helping to reduce animal use in research

Interrelationship between muscle fitness in childhood and bone mineral density in adulthood: mediation analysis of muscle fitness in adulthood

Abstract Background This study was aimed to examine the relationship between muscular fitness indicators in childhood and areal bone mineral density (aBMD) in adulthood and to verify whether the relationship is mediated by performance on muscular fitness indicators in adulthood. Methods A sample of 138 healthy adults (69 males; 22.3 years) were followed after a previous assessment at the age of 7–10 years. Stature, body mass and muscular fitness indicators (handgrip strength, standing long jump and sit-ups tests) were assessed in childhood and adulthood. Additionally, total body, upper limbs, lower limbs, right femoral neck and lumbar spine aBMD was assessed in adulthood using dual X-ray absorptiometry. Analysis included descriptive statistics; t-test or Mann-Whitney U-test for comparison between males and females, multiple linear regression for the prediction aBMD from muscular fitness indicators in childhood, mediation analysis of the respective muscular fitness indicators in adulthood and the relationship between muscular fitness indicators in childhood and aBMD. Results Males were stronger compared to females regarding muscular fitness indicators in childhood and adulthood, and presented higher mean values for aBMD in adulthood, except for lumbar spine (p < 0.05). Regression analysis revealed that some muscular fitness indicators in childhood showed significant positive relationship with bone health indicators in adulthood, such as: handgrip strength and total body aBMD (β = 0.005; R2 = 0.35; p = 0.040) and upper limbs aBMD (β = 0.005; R2 = 0.55; p = 0.019); and sit-ups test was a significant predictors of lumbar spine BMD (β = 0.003; R2 = 0.06; p = 0.039). Mediation analysis pointed out the following: adulthood handgrip strength mediated relationships between childhood handgrip strength and total aBMD (indirect effect (IE) = 0.0025; 95%CI = 0.0005–0.0048), and upper limbs aBMD (IE = 0.0040; 95%CI = 0.0017–0.0069). Conclusions Muscular fitness indicators in childhood showed significant relationship with bone health indicators in adulthood and the sit-ups test in childhood had direct effect on lumbar spine aBMD in adulthood. Adulthood handgrip strength mediated the relationship between childhood handgrip strength and total body and upper limb aBMD, pointing out that muscular fitness in childhood may be a aBMD determinant in adulthood, especially when higher muscle fitness performance is maintained in adulthood

Inhibition of SARS-CoV-2 infection in human iPSC-derived cardiomyocytes by targeting the Sigma-1 receptor disrupts cytoarchitecture and beating

SARS-CoV-2 infects cardiac cells and causes heart dysfunction. Conditions such as myocarditis and arrhythmia have been reported in COVID-19 patients. The Sigma-1 receptor (S1R) is a ubiquitously expressed chaperone that plays a central role in cardiomyocyte function. S1R has been proposed as a therapeutic target because it may affect SARS-CoV-2 replication; however, the impact of the inhibition of S1R in human cardiomyocytes remains to be described. In this study, we investigated the consequences of S1R inhibition in iPSC-derived human cardiomyocytes (hiPSC-CM). SARS-CoV-2 infection in hiPSC-CM was productive and reduced cell survival. S1R inhibition decreased both the number of infected cells and viral particles after 48 hours. S1R inhibition also prevented the release of pro-inflammatory cytokines and cell death. Although the S1R antagonist NE-100 triggered those protective effects, it compromised cytoskeleton integrity by downregulating the expression of structural-related genes and reducing beating frequency. Our findings suggest that the detrimental effects of S1R inhibition in human cardiomyocytes’ integrity may abrogate its therapeutic potential against COVID and should be carefully considered