RESUMEN
Hypoplastic left heart syndrome (HLHS) is a severe congenital cardiovascular malformation characterized by hypoplasia of the left ventricle, aorta, and other structures on the left side of the heart. The pathologic definition includes atresia or stenosis of both the aortic and mitral valves. Despite considerable progress in clinical and surgical management of HLHS, mortality and morbidity remain concerns. One barrier to progress in HLHS management is poor understanding of its cause. Several lines of evidence point to genetic origins of HLHS. First, some HLHS cases have been associated with cytogenetic abnormalities (e.g., Turner syndrome). Second, studies of family clustering of HLHS and related cardiovascular malformations have determined HLHS is heritable. Third, genomic regions that encode genes influencing the inheritance of HLHS have been identified. Taken together, these diverse studies provide strong evidence for genetic origins of HLHS and related cardiac phenotypes. However, using simple Mendelian inheritance models, identification of single genetic variants that "cause" HLHS has remained elusive, and in most cases, the genetic cause remains unknown. These results suggest that HLHS inheritance is complex rather than simple. The implication of this conclusion is that researchers must move beyond the expectation that a single disease-causing variant can be found. Utilization of complex models to analyze high-throughput genetic data requires careful consideration of study design.
Asunto(s)
Síndrome del Corazón Izquierdo Hipoplásico , Humanos , Predisposición Genética a la Enfermedad/genética , Síndrome del Corazón Izquierdo Hipoplásico/genética , FenotipoRESUMEN
Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) with underdevelopment of left-sided heart structures. While previously uniformly fatal, surgical advances now provide highly effective palliation that allows most HLHS patients to survive their critical CHD. Nevertheless, there remains high morbidity and mortality with high risk of heart failure. As hemodynamic compromise from restricted aortic blood flow has been suggested to underlie the poor LV growth, this suggests the possibility of prenatal fetal intervention to recover LV growth. As such interventions have yielded ambiguous results, the optimization of therapy will require more mechanistic insights into the developmental etiology for HLHS. Clinical studies have shown high heritability for HLHS, with an oligogenic etiology indicated in conjunction with genetic heterogeneity. This is corroborated with the recent recovery of mutant mice with HLHS. With availability-induced pluripotent stem cell (iPSC)-derived cardiomyocytes from HLHS mice and patients, new insights have emerged into the cellular and molecular etiology for the LV hypoplasia in HLHS. Cell proliferation defects were observed in conjunction with metaphase arrest and the disturbance of Hippo-YAP signaling. The left-sided restriction of the ventricular hypoplasia may result from epigenetic perturbation of pathways regulating left-right patterning. These findings suggest new avenues for fetal interventions with therapies using existing drugs that target the Hippo-YAP pathway and/or modulate epigenetic regulation.
Asunto(s)
Modelos Animales de Enfermedad , Síndrome del Corazón Izquierdo Hipoplásico , Transducción de Señal , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/patología , Síndrome del Corazón Izquierdo Hipoplásico/metabolismo , Síndrome del Corazón Izquierdo Hipoplásico/fisiopatología , Animales , Humanos , Ratones , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Células Madre Pluripotentes Inducidas/metabolismoRESUMEN
Hypoplastic left heart syndrome (HLHS) is a lethal congenital heart disease (CHD) affecting 8-25 per 100,000 neonates globally. Clinical interventions, primarily surgical, have improved the life expectancy of the affected subjects substantially over the years. However, the etiological basis of HLHS remains fundamentally unclear to this day. Based upon the existing paradigm of studies, HLHS exhibits a multifactorial mode of etiology mediated by a complicated course of genetic and signaling cascade. This review presents a detailed outline of the HLHS phenotype, the prenatal and postnatal risks, and the signaling and molecular mechanisms driving HLHS pathogenesis. The review discusses the potential limitations and future perspectives of studies that can be undertaken to address the existing scientific gap. Mechanistic studies to explain HLHS etiology will potentially elucidate novel druggable targets and empower the development of therapeutic regimens against HLHS in the future.
Asunto(s)
Síndrome del Corazón Izquierdo Hipoplásico , Embarazo , Recién Nacido , Femenino , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/patología , Síndrome del Corazón Izquierdo Hipoplásico/cirugía , Transducción de Señal , FenotipoRESUMEN
Hypoplastic left heart syndrome (HLHS) is a severe congenital heart defect (CHD) characterized by hypoplasia of the left ventricle and aorta along with stenosis or atresia of the aortic and mitral valves. HLHS represents only â¼4%-8% of all CHDs but accounts for â¼25% of deaths. HLHS is an isolated defect (i.e., iHLHS) in 70% of families, the vast majority of which are simplex. Despite intense investigation, the genetic basis of iHLHS remains largely unknown. We performed exome sequencing on 331 families with iHLHS aggregated from four independent cohorts. A Mendelian-model-based analysis demonstrated that iHLHS was not due to single, large-effect alleles in genes previously reported to underlie iHLHS or CHD in >90% of families in this cohort. Gene-based association testing identified increased risk for iHLHS associated with variation in CAPN2 (p = 1.8 × 10-5), encoding a protein involved in functional adhesion. Functional validation studies in a vertebrate animal model (Xenopus laevis) confirmed CAPN2 is essential for cardiac ventricle morphogenesis and that in vivo loss of calpain function causes hypoplastic ventricle phenotypes and suggest that human CAPN2707C>T and CAPN21112C>T variants, each found in multiple individuals with iHLHS, are hypomorphic alleles. Collectively, our findings show that iHLHS is typically not a Mendelian condition, demonstrate that CAPN2 variants increase risk of iHLHS, and identify a novel pathway involved in HLHS pathogenesis.
Asunto(s)
Síndrome del Corazón Izquierdo Hipoplásico , Animales , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Alelos , Aorta , Calpaína/genética , Ventrículos CerebralesRESUMEN
Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) with a likely oligogenic etiology, but our understanding of the genetic complexities and pathogenic mechanisms leading to HLHS is limited. We performed whole genome sequencing (WGS) on 183 HLHS patient-parent trios to identify candidate genes, which were functionally tested in the Drosophila heart model. Bioinformatic analysis of WGS data from an index family of a HLHS proband born to consanguineous parents prioritized 9 candidate genes with rare, predicted damaging homozygous variants. Of them, cardiac-specific knockdown (KD) of mitochondrial MICOS complex subunit dCHCHD3/6 resulted in drastically compromised heart contractility, diminished levels of sarcomeric actin and myosin, reduced cardiac ATP levels, and mitochondrial fission-fusion defects. These defects were similar to those inflicted by cardiac KD of ATP synthase subunits of the electron transport chain (ETC), consistent with the MICOS complex's role in maintaining cristae morphology and ETC assembly. Five additional HLHS probands harbored rare, predicted damaging variants in CHCHD3 or CHCHD6. Hypothesizing an oligogenic basis for HLHS, we tested 60 additional prioritized candidate genes from these patients for genetic interactions with CHCHD3/6 in sensitized fly hearts. Moderate KD of CHCHD3/6 in combination with Cdk12 (activator of RNA polymerase II), RNF149 (goliath, E3 ubiquitin ligase), or SPTBN1 (ß-Spectrin, scaffolding protein) caused synergistic heart defects, suggesting the likely involvement of diverse pathways in HLHS. Further elucidation of novel candidate genes and genetic interactions of potentially disease-contributing pathways is expected to lead to a better understanding of HLHS and other CHDs.
Asunto(s)
Cardiopatías Congénitas , Síndrome del Corazón Izquierdo Hipoplásico , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Actomiosina , Biología Computacional , Adenosina Trifosfato , Proteínas MitocondrialesRESUMEN
Left atrial ligation (LAL) of the chick embryonic heart is a model of the hypoplastic left heart syndrome (HLHS) where a purely mechanical intervention without genetic or pharmacological manipulation is employed to initiate cardiac malformation. It is thus a key model for understanding the biomechanical origins of HLHS. However, its myocardial mechanics and subsequent gene expressions are not well-understood. We performed finite element (FE) modeling and single-cell RNA sequencing to address this. 4D high-frequency ultrasound imaging of chick embryonic hearts at HH25 (ED 4.5) were obtained for both LAL and control. Motion tracking was performed to quantify strains. Image-based FE modeling was conducted, using the direction of the smallest strain eigenvector as the orientations of contractions, the Guccione active tension model and a Fung-type transversely isotropic passive stiffness model that was determined via micro-pipette aspiration. Single-cell RNA sequencing of left ventricle (LV) heart tissues was performed for normal and LAL embryos at HH30 (ED 6.5) and differentially expressed genes (DEG) were identified.After LAL, LV thickness increased by 33%, strains in the myofiber direction increased by 42%, while stresses in the myofiber direction decreased by 50%. These were likely related to the reduction in ventricular preload and underloading of the LV due to LAL. RNA-seq data revealed potentially related DEG in myocytes, including mechano-sensing genes (Cadherins, NOTCH1, etc.), myosin contractility genes (MLCK, MLCP, etc.), calcium signaling genes (PI3K, PMCA, etc.), and genes related to fibrosis and fibroelastosis (TGF-ß, BMP, etc.). We elucidated the changes to the myocardial biomechanics brought by LAL and the corresponding changes to myocyte gene expressions. These data may be useful in identifying the mechanobiological pathways of HLHS.
Asunto(s)
Fibrilación Atrial , Síndrome del Corazón Izquierdo Hipoplásico , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/diagnóstico por imagen , Síndrome del Corazón Izquierdo Hipoplásico/genética , Fenómenos Biomecánicos , Miocardio/metabolismo , Atrios Cardíacos/diagnóstico por imagen , Ventrículos CardíacosRESUMEN
BACKGROUND: Hypoplastic left heart syndrome (HLHS) is a rare but genetically complex and clinically and anatomically severe form of congenital heart disease (CHD). CASE PRESENTATION: Here, we report on the use of rapid prenatal whole-exome sequencing for the prenatal diagnosis of a severe case of neonatal recurrent HLHS caused by heterozygous compound variants in the MYH6 gene inherited from the (healthy) parents. MYH6 is known to be highly polymorphic; a large number of rare and common variants have variable effects on protein levels. We postulated that two hypomorphic variants led to severe CHD when associated in trans; this was consistent with the autosomal recessive pattern of inheritance. In the literature, dominant transmission of MYH6-related CHD is more frequent and is probably linked to synergistic heterozygosity or the specific combination of a single, pathogenic variant with common MYH6 variants. CONCLUSIONS: The present report illustrates the major contribution of whole-exome sequencing (WES) in the characterization of an unusually recurrent fetal disorder and considered the role of WES in the prenatal diagnosis of disorders that do not usually have a genetic etiology.
Asunto(s)
Cardiopatías Congénitas , Herencia , Síndrome del Corazón Izquierdo Hipoplásico , Embarazo , Recién Nacido , Femenino , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/diagnóstico por imagen , Síndrome del Corazón Izquierdo Hipoplásico/genética , Cardiopatías Congénitas/genética , Diagnóstico Prenatal , Cadenas Pesadas de Miosina/genética , Miosinas Cardíacas/genéticaRESUMEN
Hypoplastic left heart syndrome (HLHS) is a congenital heart malformation clinically characterized by an underdeveloped left ventricle, mitral or aortic valve stenosis or atresia, and narrowed ascending aorta. Although genetic etiology of HLHS is heterogenous, recurrent NOTCH1 variants have been associated with this defect. We report generation of an iPSC line derived from a female with HLHS with a heterozygous missense NOTCH1 (c.2058G > A; p.Gly661Ser) mutation within the conserved EGF-like repeat 17. This iPSC line exhibited typical cellular morphology, normal karyotype, high expression of pluripotent markers, and trilineage differentiation potential; and can be leveraged to dissect the complex NOTCH1-mediated HLHS disease mechanism.
Asunto(s)
Cardiopatías Congénitas , Síndrome del Corazón Izquierdo Hipoplásico , Células Madre Pluripotentes Inducidas , Humanos , Femenino , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Cardiopatías Congénitas/metabolismo , Mutación/genética , Heterocigoto , Receptor Notch1/genética , Receptor Notch1/metabolismoRESUMEN
BACKGROUND: Deciphering hypoplastic left heart syndrome (HLHS) pathogenesis is confounded by its genetic heterogeneity and oligogenic underpinnings. METHODS: Whole genome sequences were analyzed by 3 independent strategies to identify HLHS gene candidates, ranked by variant, gene, and disease-level metrics. RESULTS: First, a genome-wide association study of 174 cases and 853 controls revealed suggestive association with a MYO18B intron 33 variant (rs2269628-G; frequency=0.55 versus 0.39; OR, 1.97 [95% CI, 1.54-2.52]; P=6.70×10-8). Second, transmission disequilibrium testing of 161 HLHS proband-parent trios revealed overrepresentation of a MYO18B intron 42 variant (rs73154186-A; frequency=0.05; OR, 24 [95% CI, 3.2-177.4]; P=4.23×10-6). Third, rare, predicted-damaging variants were filtered in 2 multiplex families. In 141H, 2 fifth-degree relatives with HLHS shared a paternally-inherited MYO5A missense variant (p.Arg801Trp; frequency=0.00003; combined annotation-dependent depletion score=29), each with a maternally-inherited or de novo candidate modifier variant in a MYO5A-interacting conventional myosin. In 442H, a HLHS proband was compound heterozygous for MYO15A variants-a maternally-inherited pathogenic stop-gain variant co-segregating with tetralogy of Fallot and bicuspid aortic valve in maternal relatives (p.Tyr2819Ter; frequency=0.00003) and a paternally-inherited intronic variant altering a canonical transcription factor binding site (rs1277068603; frequency=0.00001; position weight matrix score=0.98). CONCLUSIONS: Collectively, these findings suggest that common and rare alleles within unconventional myosin genes are associated with HLHS susceptibility. The identified candidate MYO18B regulates cardiac sarcomerogenesis, supporting the hypothesis of intrinsic myogenic perturbation in arrested left heart development.
Asunto(s)
Enfermedad de la Válvula Aórtica Bicúspide , Síndrome del Corazón Izquierdo Hipoplásico , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Estudio de Asociación del Genoma Completo , Mutación , Patrón de HerenciaRESUMEN
Hypoplastic left heart syndrome (HLHS) is a rare but fatal birth defect in which the left side of the heart is underdeveloped. HLHS accounts for 2% to 4% of congenital heart anomalies. Whole genome sequencing (WGS) was conducted for a family trio consisting of a proband and his parents. A homozygous rare variant was detected in the PTPRB (Protein Tyrosine Phosphatase Receptor Type B) gene of the proband by functional annotation and co-segregation analysis. Sanger sequencing was used to confirm genotypes of the variant. The in silico prediction tools, including Mutation Taster, SpliceAI, and CADD, were used to predict the impact of the mutation. The allele frequencies across populations were compared based on multiple databases, including "1000 genomes" and "gnomAD". We used two vectors (pcMINI and pcDNA3.1) to generate a minigene construct to validate the mutational effect at the transcriptional level. Family-based WGS analyses showed that only a homozygous splice acceptor variant (NC_000012.12: g.70636068T>G, NM_001109754.4: c.56-2A>C, NG_029940.2: g.6373A>C) at the exon-intron border of PTPRB gene associates with HLHS. This variant is also within the region with the enhancer activity based on UCSC genome annotation. Genotyping and Sanger sequencing revealed that the proband's parents are heterozygous for this variant. Evolutionary conservation analysis revealed that the site (NC_000012.12: g.70636068) is extremely conserved across species, supporting the evolutionary functional constraints of the ancestral wild type (T). In silico tools universally predicted a deleterious or disease-causing impact of the mutation from T to G. The mutation was not found in the 1000 genomes and gnomAD databases, which indicates that this mutation is very rare in most human populations. A splicing assay indicated that the mutated minigene caused aberrant splicing of mRNA, in which a 3 bp missing in the second exon resulted in the deletion of one amino acid (NP_001103224.1:p.Glu19del) compared to the normal protein of PRPTB (also the VE-PTP). Structure prediction revealed that the deletion occurred within the C-region of the signal peptide of VE-PTP, suggesting signal peptide-related defects as a potential mechanism for the HLHS cellular pathogeny. We report a rare homozygous variant with splicing error in PTPRB associated with HLHS. Previous model species studies revealed conserved functions of PTPRB in cardiovascular and heart development in mice and zebrafish. Our study is the first report to show the association between PTPRB and HLHS in humans.
Asunto(s)
Síndrome del Corazón Izquierdo Hipoplásico , Humanos , Ratones , Animales , Síndrome del Corazón Izquierdo Hipoplásico/genética , Pez Cebra , Familia , Padres , Proteínas Tirosina Fosfatasas Clase 3 Similares a ReceptoresRESUMEN
Noonan syndrome is an inherited disorder caused by alterations in the RAS-MAPK pathway. There have been several identified genotype-phenotype associations made with respect to congenital cardiac lesions and Noonan syndrome variants, but limited data exist regarding single ventricle disease in this population. Here, we report two patients with PTPN11-related Noonan syndrome and hypoplastic left heart syndrome variants.
Asunto(s)
Síndrome del Corazón Izquierdo Hipoplásico , Síndrome de Noonan , Humanos , Síndrome de Noonan/complicaciones , Síndrome de Noonan/diagnóstico , Síndrome de Noonan/genética , Síndrome del Corazón Izquierdo Hipoplásico/complicaciones , Síndrome del Corazón Izquierdo Hipoplásico/genética , Mutación , Estudios de Asociación Genética , FenotipoRESUMEN
Hypoplastic left heart syndrome (HLHS) is characterized by underdevelopment of left sided structures including the ventricle, valves, and aorta. Prevailing paradigm suggests that HLHS is a multigenic disease of co-occurring phenotypes. Here, we report that zebrafish lacking two orthologs of the RNA binding protein RBFOX2, a gene linked to HLHS in humans, display cardiovascular defects overlapping those in HLHS patients including ventricular, valve, and aortic deficiencies. In contrast to current models, we demonstrate that these structural deficits arise secondary to impaired pump function as these phenotypes are rescued when Rbfox is specifically expressed in the myocardium. Mechanistically, we find diminished expression and alternative splicing of sarcomere and mitochondrial components that compromise sarcomere assembly and mitochondrial respiration, respectively. Injection of human RBFOX2 mRNA restores cardiovascular development in rbfox mutant zebrafish, while HLHS-linked RBFOX2 variants fail to rescue. This work supports an emerging paradigm for HLHS pathogenesis that centers on myocardial intrinsic defects.
Asunto(s)
Síndrome del Corazón Izquierdo Hipoplásico , Animales , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/patología , Miocardio/metabolismo , Factores de Empalme de ARN/genética , Factores de Empalme de ARN/metabolismo , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/metabolismo , Proteínas Represoras/metabolismo , Pez Cebra/genética , Pez Cebra/metabolismoRESUMEN
Despite a strong genetic component, only a few genes have been identified in congenital heart diseases (CHDs). We introduced systems analyses to uncover the hidden organization on biological networks of mutations in CHDs and leveraged network analysis to integrate the protein interactome, patient exomes, and single-cell transcriptomes of the developing heart. We identified a CHD network regulating heart development and observed that a sub-network also regulates fetal brain development, thereby providing mechanistic insights into the clinical comorbidities between CHDs and neurodevelopmental conditions. At a small scale, we experimentally verified uncharacterized cardiac functions of several proteins. At a global scale, our study revealed developmental dynamics of the network and observed its association with the hypoplastic left heart syndrome (HLHS), which was further supported by the dysregulation of the network in HLHS endothelial cells. Overall, our work identified previously uncharacterized CHD factors and provided a generalizable framework applicable to studying many other complex diseases. A record of this paper's Transparent Peer Review process is included in the supplemental information.
Asunto(s)
Cardiopatías Congénitas , Síndrome del Corazón Izquierdo Hipoplásico , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/metabolismo , Células Endoteliales/metabolismo , Cardiopatías Congénitas/genética , Mutación/genética , Análisis de SistemasRESUMEN
Hypoplastic left heart syndrome (HLHS) is a relatively rare severe congenital heart defect (CHD) closely linked to other left ventricular outflow tract (LVOT) lesions including bicuspid aortic valve (BAV), one of the most common heart defects. While HLHS, BAV, and other LVOT lesions have a strong genetic underpinning, their genetic etiology remains poorly understood. Findings from a large-scale mouse mutagenesis screen showed HLHS has a multigenic etiology and is genetically heterogenous, explaining difficulties in identifying the genetic causes of HLHS. In Ohia mice, HLHS shows incomplete penetrance. Some mice exhibited small LV with normal aorta, and others a normal LV with hypoplastic aorta, indicating the LV hypoplasia is not hemodynamically driven. In Ohia mutants, HLHS was found to have a digenic modular construction, with mutation in a chromatin modifier causing the small LV phenotype and mutation in Pcdha9 causing the aorta/aortic valve hypoplasia. The Pcdha9 mutation alone can cause BAV, and in the human genome two common deletion copy number variants spanning PCDHA7-10 are associated with BAV. Hence the digenic etiology of HLHS can account for the close association of HLHS, a rare CHD, with BAV, one of the most common CHD. Functional analysis of Ohia HLHS heart tissue showed severe mitochondrial dysfunction in the small LV, while the normal size RV is also affected but milder, suggesting possible role in vulnerability of surgically palliated HLHS patients to heart failure. These findings suggest insights into the genetics of HLHS may yield new therapies for improving outcome for patients with HLHS.
Asunto(s)
Enfermedad de la Válvula Aórtica Bicúspide , Cardiopatías Congénitas , Síndrome del Corazón Izquierdo Hipoplásico , Animales , Válvula Aórtica/anomalías , Válvula Aórtica/cirugía , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/cirugía , Ratones , MutaciónRESUMEN
The heart, the first organ to develop in the embryo, undergoes complex morphogenesis that when defective results in congenital heart disease (CHD). With current therapies, more than 90% of patients with CHD survive into adulthood, but many suffer premature death from heart failure and non-cardiac causes1. Here, to gain insight into this disease progression, we performed single-nucleus RNA sequencing on 157,273 nuclei from control hearts and hearts from patients with CHD, including those with hypoplastic left heart syndrome (HLHS) and tetralogy of Fallot, two common forms of cyanotic CHD lesions, as well as dilated and hypertrophic cardiomyopathies. We observed CHD-specific cell states in cardiomyocytes, which showed evidence of insulin resistance and increased expression of genes associated with FOXO signalling and CRIM1. Cardiac fibroblasts in HLHS were enriched in a low-Hippo and high-YAP cell state characteristic of activated cardiac fibroblasts. Imaging mass cytometry uncovered a spatially resolved perivascular microenvironment consistent with an immunodeficient state in CHD. Peripheral immune cell profiling suggested deficient monocytic immunity in CHD, in agreement with the predilection in CHD to infection and cancer2. Our comprehensive phenotyping of CHD provides a roadmap towards future personalized treatments for CHD.
Asunto(s)
Cardiopatías Congénitas , Fenotipo , Receptores de Proteínas Morfogenéticas Óseas/metabolismo , Cardiomiopatía Dilatada/genética , Cardiomiopatía Dilatada/inmunología , Cardiomiopatía Dilatada/metabolismo , Cardiomiopatía Dilatada/patología , Cardiomiopatía Hipertrófica/genética , Cardiomiopatía Hipertrófica/inmunología , Cardiomiopatía Hipertrófica/metabolismo , Cardiomiopatía Hipertrófica/patología , Progresión de la Enfermedad , Fibroblastos/metabolismo , Fibroblastos/patología , Factores de Transcripción Forkhead/metabolismo , Cardiopatías Congénitas/genética , Cardiopatías Congénitas/inmunología , Cardiopatías Congénitas/metabolismo , Cardiopatías Congénitas/patología , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/inmunología , Síndrome del Corazón Izquierdo Hipoplásico/metabolismo , Síndrome del Corazón Izquierdo Hipoplásico/patología , Citometría de Imagen , Resistencia a la Insulina , Monocitos/inmunología , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , RNA-Seq , Transducción de Señal/genética , Análisis de la Célula Individual , Tetralogía de Fallot/genética , Tetralogía de Fallot/inmunología , Tetralogía de Fallot/metabolismo , Tetralogía de Fallot/patología , Proteínas Señalizadoras YAP/metabolismoRESUMEN
Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) affecting 1 in 5000 newborns. We constructed the interactome of 74 HLHS-associated genes identified from a large-scale mouse mutagenesis screen, augmenting it with 408 novel protein-protein interactions (PPIs) using our High-Precision Protein-Protein Interaction Prediction (HiPPIP) model. The interactome is available on a webserver with advanced search capabilities. A total of 364 genes including 73 novel interactors were differentially regulated in tissue/iPSC-derived cardiomyocytes of HLHS patients. Novel PPIs facilitated the identification of TOR signaling and endoplasmic reticulum stress modules. We found that 60.5% of the interactome consisted of housekeeping genes that may harbor large-effect mutations and drive HLHS etiology but show limited transmission. Network proximity of diabetes, Alzheimer's disease, and liver carcinoma-associated genes to HLHS genes suggested a mechanistic basis for their comorbidity with HLHS. Interactome genes showed tissue-specificity for sites of extracardiac anomalies (placenta, liver and brain). The HLHS interactome shared significant overlaps with the interactomes of ciliopathy- and microcephaly-associated genes, with the shared genes enriched for genes involved in intellectual disability and/or developmental delay, and neuronal death pathways, respectively. This supported the increased burden of ciliopathy variants and prevalence of neurological abnormalities observed among HLHS patients with developmental delay and microcephaly, respectively.
Asunto(s)
Ciliopatías , Síndrome del Corazón Izquierdo Hipoplásico , Células Madre Pluripotentes Inducidas , Microcefalia , Malformaciones del Sistema Nervioso , Animales , Ciliopatías/metabolismo , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/metabolismo , Células Madre Pluripotentes Inducidas/metabolismo , Recién Nacido , Ratones , Microcefalia/genética , Microcefalia/metabolismo , Miocitos Cardíacos/metabolismoRESUMEN
Single ventricle heart defects (SVHDs) are a severe type of congenital heart disease with poorly understood pathogenic mechanisms. New research using patient-specific induced pluripotent stem cells (iPSCs) as a cellular model is beginning to uncover genetic and cellular etiologies of SVHDs. Hypoplastic left heart syndrome (HLHS) is a type of SVHD that is characterized by an underdeveloped left ventricle and other malformations in the left side of the heart. Hypoplastic right heart syndrome (HRHS), the second type of SVHD, is characterized by an underdeveloped right heart, including malformed tricuspid and pulmonary valves. Despite a noticeable lack of research on SVHD, emerging technologies offer a promising future to further probe the genetic and cellular mechanisms of these diseases. Pediatric cardiovascular research is at the dawn of a new era in terms of what can be discovered with patient-specific iPSCs in conjunction with other technologies (e.g., organoids, single-cell genomics, CRISPR/Cas9 genome editing). In this review, we present recent approaches and findings utilizing patient-specific iPSCs to identify cellular mechanisms responsible for improper cardiac organogenesis in HLHS and HRHS.
Asunto(s)
Cardiopatías Congénitas , Síndrome del Corazón Izquierdo Hipoplásico , Células Madre Pluripotentes Inducidas , Niño , Cardiopatías Congénitas/genética , Ventrículos Cardíacos/anomalías , Humanos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/patología , Células Madre Pluripotentes Inducidas/patologíaRESUMEN
BACKGROUND: Hypoplastic left heart syndrome and single ventricle variants with aortic hypoplasia are commonly classified as severe forms of CHD. We hypothesised patients with these severe defects and reported genetic abnormalities have increased morbidity and mortality during the interstage period. METHODS AND RESULTS: This was a retrospective review of the National Pediatric Cardiology Quality Improvement Collaborative Phase I registry. Three patient groups were identified: major syndromes, other genetic abnormalities, and no reported genetic abnormality. Tukey post hoc test was applied for pairwise group comparisons of length of stay, death, and combined outcome of death, not a candidate for stage 2 palliation, and heart transplant. Participating centres received a survey to establish genetic testing and reporting practices. Of the 2182 patients, 110 (5%) had major genetic syndromes, 126 (6%) had other genetic abnormalities, and 1946 (89%) had no genetic abnormality. Those with major genetic syndromes weighed less at birth and stage 1 palliation. Patients with no reported genetic abnormalities reached full oral feeds sooner and discharged earlier. The combined outcome of death, not a candidate for stage 2 palliation, and heart transplant was more common in those with major syndromes. Survey response was low (n = 23, 38%) with only 14 (61%) routinely performing and reporting genetic testing. CONCLUSIONS: Patients with genetic abnormalities experienced greater morbidity and mortality during the interstage period than those with no reported genetic abnormalities. Genetic testing and reporting practices vary significantly between participating centres.
Asunto(s)
Síndrome del Corazón Izquierdo Hipoplásico , Procedimientos de Norwood , Recién Nacido , Niño , Humanos , Lactante , Procedimientos de Norwood/métodos , Resultado del Tratamiento , Cuidados Paliativos/métodos , Síndrome del Corazón Izquierdo Hipoplásico/genética , Síndrome del Corazón Izquierdo Hipoplásico/cirugía , Estudios Retrospectivos , Morbilidad , Factores de RiesgoRESUMEN
BACKGROUND: Whole-genome sequencing in families enables deciphering of congenital heart disease causes. A shared genetic basis for familial bicuspid aortic valve (BAV) and hypoplastic left heart syndrome (HLHS) was postulated. METHODS: Whole-genome sequencing was performed in affected members of 6 multiplex BAV families, an HLHS cohort of 197 probands and 546 relatives, and 813 controls. Data were filtered for rare, predicted-damaging variants that cosegregated with familial BAV and disrupted genes associated with congenital heart disease in humans and mice. Candidate genes were further prioritized by rare variant burden testing in HLHS cases versus controls. Modifier variants in HLHS proband-parent trios were sought to account for the severe developmental phenotype. RESULTS: In 5 BAV families, missense variants in 6 ontologically diverse genes for structural (SPTBN1, PAXIP1, and FBLN1) and signaling (CELSR1, PLXND1, and NOS3) proteins fulfilled filtering metrics. CELSR1, encoding cadherin epidermal growth factor laminin G seven-pass G-type receptor, was identified as a candidate gene in 2 families and was the only gene demonstrating rare variant enrichment in HLHS probands (P=0.003575). HLHS-associated CELSR1 variants included 16 missense, one splice site, and 3 noncoding variants predicted to disrupt canonical transcription factor binding sites, most of which were inherited from a parent without congenital heart disease. Filtering whole-genome sequencing data for rare, predicted-damaging variants inherited from the other parent revealed 2 cases of CELSR1 compound heterozygosity, one case of CELSR1-CELSR3 synergistic heterozygosity, and 4 cases of CELSR1-MYO15A digenic heterozygosity. CONCLUSIONS: CELSR1 is a susceptibility gene for familial BAV and HLHS, further implicating planar cell polarity pathway perturbation in congenital heart disease.