RESUMEN

BACKGROUND: Marfan syndrome (MFS) is a complex genetic systemic connective tissue disorder. It is well known that genetic factors play a critical role in the progression of MFS, with nearly all cases attributed to variants in the FBN1 gene. METHODS: We investigated a Chinese family with MFS spanning two generations. Whole exome sequencing, in silico analysis, minigene constructs, transfection, RT-PCR, and protein secondary structure analysis were used to analyze the genotype of the proband and his father. RESULTS: The main clinical manifestations of the proband and his father were subluxation of the left lens and high myopia with pectus deformity. Whole exome sequencing identified a novel single nucleotide variant (SNV) in the FBN1 gene at a non-canonical splice site, c.443-3C>G. This variant resulted in two abnormal mRNA transcripts, leading to a frameshift and an in-frame insertion. Further in vitro experiments indicated that the c.443-3C>G variant in FBN1 was pathogenic and functionally harmful. CONCLUSION: This research identified a novel intronic pathogenic FBN1: c.443-3C>G gene variant, which led to two different aberrant splicing effects. Further functional analysis expands the variant spectrum and provides a strong indication and sufficient basis for preimplantation genetic testing for monogenic disease (PGT-M).

Asunto(s)

Fibrilina-1 , Heterocigoto , Intrones , Síndrome de Marfan , Linaje , Empalme del ARN , Humanos , Síndrome de Marfan/genética , Síndrome de Marfan/patología , Fibrilina-1/genética , Masculino , Adulto , Femenino , Adipoquinas

RESUMEN

Genetic factors play a significant role in the pathogenesis of mitral valve diseases, including mitral valve prolapse (MVP) and mitral valve regurgitation. Genes like Fibrillin-1 (FBN1), Filamin A (FLNA), matrix metalloproteinase 2 (MMP2), and SRY-box transcription factor 9 (SOX9) are known to influence mitral valve pathology but knowledge of the exact mechanism is far from clear. Data regarding serum parameters, transesophageal echocardiography, and genetic and histopathologic parameters were investigated in 54 patients who underwent cardiovascular surgery for mitral valve regurgitation. The possible association between Fibrillin-1, Filamin A, MMP2, and SOX9 gene expressions was checked in relationship with the parameters of systemic inflammatory response. The mRNA expression levels (RQ-relative quantification) were categorized into three distinct groups: low (RQ < 1), medium/normal (RQ = 1-2), and high (RQ > 2). Severe fibrosis of the mitral valve was reflected by high expression of FBN1 and low expression of MMP2 (p < 0.05). The myxoid degeneration level was associated with the mRNA expression level for FBN1 and a low lymphocyte-monocyte ratio was associated with an increased mRNA expression of FBN1 (p < 0.05). A high number of monocytes was associated with high values of FBN1 whereas the increase in the number of lymphocytes was associated with high levels of MMP2. In addition, we observed that the risk of severe hyalinization was enhanced by a low mRNA expression of FLNA and/or SOX9. In conclusion, a lower FLNA mRNA expression can reflect the aging process that is highlighted in mitral valve pathology as a higher risk for hyalinization, especially in males, that might be prevented by upregulation of the SOX9 gene. FBN1 and MMP2 influence the inflammation-related fibrotic degeneration of the mitral valve. Understanding the genetic base of mitral valve pathology can provide insights into disease mechanisms, risk stratification, and potential therapeutic targets.

Asunto(s)

Fibrilina-1 , Filaminas , Metaloproteinasa 2 de la Matriz , Válvula Mitral , Factor de Transcripción SOX9 , Humanos , Fibrilina-1/genética , Fibrilina-1/metabolismo , Factor de Transcripción SOX9/metabolismo , Factor de Transcripción SOX9/genética , Filaminas/metabolismo , Filaminas/genética , Masculino , Femenino , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 2 de la Matriz/genética , Persona de Mediana Edad , Válvula Mitral/patología , Válvula Mitral/metabolismo , Anciano , Prolapso de la Válvula Mitral/genética , Prolapso de la Válvula Mitral/metabolismo , Prolapso de la Válvula Mitral/patología , Insuficiencia de la Válvula Mitral/genética , Insuficiencia de la Válvula Mitral/metabolismo , Insuficiencia de la Válvula Mitral/patología , Adipoquinas

RESUMEN

Triple-negative breast cancer (TNBC) is a subtype of breast cancer with a poor prognosis and limited treatment options. This study evaluates the prognostic value of stromal markers in TNBC, focusing on the tumor-stroma ratio (TSR) and overall stroma ratio (OSR) in whole slide images (WSI), as well as the expression of type-I collagen, type-III collagen, and fibrillin-1 on tissue microarrays (TMAs), using both visual assessment and digital image analysis (DIA). A total of 101 female TNBC patients, primarily treated with surgery between 2005 and 2016, were included. We found that high visual OSR correlates with worse overall survival (OS), advanced pN categories, lower stromal tumor-infiltrating lymphocyte count (sTIL), lower mitotic index, and patient age (p < 0.05). TSR showed significant connections to the pN category and mitotic index (p < 0.01). High expression levels of type-I collagen (>45%), type-III collagen (>30%), and fibrillin-1 (>20%) were linked to significantly worse OS (p = 0.004, p = 0.013, and p = 0.005, respectively) and progression-free survival (PFS) (p = 0.028, p = 0.025, and p = 0.002, respectively), validated at the mRNA level. Our results highlight the importance of stromal characteristics in promoting tumor progression and metastasis and that targeting extracellular matrix (ECM) components may offer novel therapeutic strategies. Furthermore, DIA can be more accurate and objective in evaluating TSR, OSR, and immunodetected stromal markers than traditional visual examination.

Asunto(s)

Biomarcadores de Tumor , Neoplasias de la Mama Triple Negativas , Humanos , Femenino , Neoplasias de la Mama Triple Negativas/patología , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/mortalidad , Pronóstico , Persona de Mediana Edad , Biomarcadores de Tumor/metabolismo , Anciano , Adulto , Células del Estroma/metabolismo , Células del Estroma/patología , Proteínas de la Matriz Extracelular/metabolismo , Proteínas de la Matriz Extracelular/genética , Fibrilina-1/metabolismo , Fibrilina-1/genética , Procesamiento de Imagen Asistido por Computador/métodos , Colágeno Tipo I/metabolismo , Colágeno Tipo I/genética , Colágeno Tipo III/metabolismo , Colágeno Tipo III/genética , Anciano de 80 o más Años

RESUMEN

Marfan syndrome (MFS) is a hereditary condition accompanied by disorders in the structural and regulatory properties of connective tissue, including elastic fibers, due to a mutation in the gene encodes for fibrillin-1 protein (FBN1 gene) and the synthesis of abnormal fibrillin-1 glycoprotein. Despite the high potential of mast cells (MCs) to remodel the extracellular matrix (ECM), their pathogenetic significance in MFS has not been considered yet. The group of patients with Marfan syndrome included two mothers and five children (three girls aged 4, 11, and 11 and two boys aged 12 and 13). Normal skin was examined in two children aged 11 and 12. Histochemical, monoplex, and multiplex immunohistochemical techniques; combined protocols of simultaneous histochemical and immunohistochemical staining (the results of staining were assessed using light, epifluorescence, and confocal microscopy); and bioinformatics algorithms for the quantitative analysis of detected targets were used to evaluate mast cells and their relationship with other cells from extracellular structures in the skin dermis. Analysis of the skin MC population in children with Marfan syndrome revealed a considerably increased number of intra-organic populations with the preservation of the specific Tryptase+Chymase+CPA3+ protease profile typical of the skin. The features of the MC histotopography phenotype in MFS consisted of closer colocalization with elastic fibers, smooth muscle cells, and fibroblasts. MCs formed many intradermal clusters that synchronized the activity of cell functions in the stromal landscape of the tissue microenvironment with the help of spatial architectonics, including the formation of cell chains and the creation of fibrous niches. In MCs, the expression of specific proteases, TGF-ß, and heparin increased, with targeted secretion of biologically active substances relative to the dermal elastic fibers, which had specific structural features in MFS, including abnormal variability in thickness along their entire length, alternating thickened and thinned areas, and uneven surface topography. This paper discusses the potential role of MCs in strain analysis (tensometry) of the tissue microenvironment in MFS. Thus, the quantitative and qualitative rearrangements of the skin MC population in MFS are aimed at altering the stromal landscape of the connective tissue. The results obtained should be taken into account when managing clinical signs of MFS manifested in other pathogenetically critical structures of internal organs, including the aorta, tendons, cartilage, and parenchymal organs.

Asunto(s)

Dermis , Tejido Elástico , Síndrome de Marfan , Mastocitos , Humanos , Síndrome de Marfan/metabolismo , Síndrome de Marfan/patología , Síndrome de Marfan/genética , Mastocitos/metabolismo , Mastocitos/patología , Niño , Masculino , Femenino , Tejido Elástico/metabolismo , Tejido Elástico/patología , Preescolar , Dermis/patología , Dermis/metabolismo , Adolescente , Fibrilina-1/metabolismo , Fibrilina-1/genética , Piel/metabolismo , Piel/patología , Matriz Extracelular/metabolismo , Adipoquinas

RESUMEN

Vascular smooth muscle cells (VSMCs) play a critical role in maintaining vascular integrity. VSMC dysfunction leads to numerous vascular diseases. Adenosine deaminases acting on RNA 1 (ADAR1), an RNA editing enzyme, has shown both RNA editing and non-editing functions. Global deletion of ADAR1 causes embryonic lethality, but the phenotype of homozygous ADAR1 deletion specifically in SMCs (ADAR1sm-/-) remains to be determined. By crossing ADAR1fl/fl mice with Myh11-CreERT2 mice followed by Tamoxifen induction, we found that ADAR1sm-/- leads to lethality in adult mice 14 days after the induction. Gross examination revealed extensive hemorrhage and detrimental vascular damage in different organs. Histological analyses revealed destruction of artery structural integrity with detachment of elastin laminae from VSMCs in ADAR1sm-/- aortas. Furthermore, ADAR1sm-/- resulted in severe VSMC apoptosis and mitochondrial dysfunction. RNA sequencing analyses of ADAR1sm-/- aorta segments demonstrated profound transcriptional alteration of genes impacting vascular health including a decrease in fibrillin-1 expression. More importantly, ADAR1sm-/- disrupts the elastin and fibrillin-1 interaction, a molecular event essential for artery structure. Our results indicate that ADAR1 plays a critical role in maintaining SMC survival and vascular stability and resilience.

Asunto(s)

Adenosina Desaminasa , Homeostasis , Músculo Liso Vascular , Miocitos del Músculo Liso , Animales , Adenosina Desaminasa/metabolismo , Adenosina Desaminasa/genética , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patología , Ratones , Miocitos del Músculo Liso/metabolismo , Miocitos del Músculo Liso/patología , Aorta/metabolismo , Aorta/patología , Apoptosis/genética , Fibrilina-1/genética , Fibrilina-1/metabolismo , Elastina/metabolismo , Ratones Noqueados , Ratones Endogámicos C57BL , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/genética

RESUMEN

Nonsyndromic sporadic thoracic aortic aneurysm (nssTAA) is characterized by diverse genetic variants that may vary in different populations. Our aim was to identify clinically relevant variants in genes implicated in hereditary aneurysms in Russian patients with nssTAA. Forty-one patients with nssTAA without dissection were analyzed. Using massive parallel sequencing, we searched for variants in exons of 53 known disease-causing genes. Patients were found to have no (likely) pathogenic variants in the genes of hereditary TAA. Six variants of uncertain significance (VUSs) were identified in four (9.8%) patients. Three VUSs [FBN1 c.7841C>T (p.Ala2614Val), COL3A1 c.2498A>T (p.Lys833Ile), and MYH11 c.4993C>T (p.Arg1665Cys)] are located in genes with "definitive" disease association (ClinGen). The remaining variants are in "potentially diagnostic" genes or genes with experimental evidence of disease association [NOTCH1 c.964G>A (p.Val322Met), COL4A5 c.953C>G (p.Pro318Arg), and PLOD3 c.833G>A (p.Gly278Asp)]. Russian patients with nssTAA without dissection examined in this study have ≥1 VUSs in six known genes of hereditary TAA (FBN1, COL3A1, MYH11, NOTCH1, COL4A5, or PLOD3). Experimental studies expanded genetic testing, and clinical examination of patients and first/second-degree relatives may shift VUSs to the pathogenic (benign) category or to a new class of rare "predisposing" low-penetrance variants causing the pathology if combined with other risk factors.

Asunto(s)

Aneurisma de la Aorta Torácica , Predisposición Genética a la Enfermedad , Humanos , Femenino , Masculino , Federación de Rusia/epidemiología , Aneurisma de la Aorta Torácica/genética , Persona de Mediana Edad , Adulto , Cadenas Pesadas de Miosina/genética , Fibrilina-1/genética , Colágeno Tipo III/genética , Anciano , Miosinas Cardíacas/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Mutación , Variación Genética , Adipoquinas

RESUMEN

Mutations in fibrillin 1 (FBN1) is the main cause of Marfan syndrome (MFS) with thoracic aortic aneurysm (TAA) as the main complication. Activation of the complement system plays a key role in the formation of thoracic and abdominal aortic aneurysms. However, the role of the complement system in MFS-associated aortic aneurysms remains unclear. In this study, we observed increased levels of complement C3a and C5a in the plasma of MFS patients and mouse, and the increased deposition of the activated complement system product C3b/iC3b was also observed in the elastic fiber rupture zone of 3-month-old MFS mice. The expression of C3a receptor (C3aR) was increased in MFS aortas, and recombinant C3a promoted the expression of cytokines in macrophages. The administration of a C3aR antagonist (C3aRA) attenuated the development of thoracic aortic aneurysms in MFS mice. The increased inflammation response and matrix metalloproteinases activities were also attenuated by C3aRA treatment in MFS mice. Therefore, these findings indicate that the complement C3a/C3aR inhibition alleviates the formation of aortic aneurysm in Marfan syndrome mice.

Asunto(s)

Adipoquinas , Aneurisma de la Aorta Torácica , Complemento C3a , Fibrilina-1 , Síndrome de Marfan , Receptores de Complemento , Animales , Femenino , Humanos , Masculino , Ratones , Adipoquinas/genética , Aorta Torácica/patología , Aneurisma de la Aorta Torácica/prevención & control , Aneurisma de la Aorta Torácica/etiología , Aneurisma de la Aorta Torácica/metabolismo , Aneurisma de la Aorta Torácica/patología , Complemento C3a/antagonistas & inhibidores , Complemento C3a/metabolismo , Citocinas/metabolismo , Modelos Animales de Enfermedad , Fibrilina-1/genética , Mediadores de Inflamación/metabolismo , Macrófagos/metabolismo , Macrófagos/efectos de los fármacos , Síndrome de Marfan/complicaciones , Síndrome de Marfan/genética , Síndrome de Marfan/tratamiento farmacológico , Ratones Endogámicos C57BL , Receptores de Complemento/antagonistas & inhibidores , Receptores Acoplados a Proteínas G , Transducción de Señal

RESUMEN

Marfan syndrome (MFS) is a hereditary condition caused by mutations in the FBN1 gene. Genetic mutations in the FBN1 locus impact the function of the encoded protein, Fibrillin 1, a structural molecule forming microfibrils found in the connective tissue. MFS patients develop severe cardiovascular complications including thoracic aortic aneurysm and aortic dissection, which predispose them to an enhanced risk of premature death. Here, we generated two induced pluripotent stem cell (iPSC) lines harboring mutations in the FBN1 gene (p.C1942C>A and c.1954 T>C), directly derived from MFS patients. We have shown that both iPSC lines displayed expression of pluripotency markers, normal karyotype and ability of trilineage differentiation, representing a valuable tool for the identification of new therapeutic strategies for intervening in this disease.

Asunto(s)

Fibrilina-1 , Células Madre Pluripotentes Inducidas , Síndrome de Marfan , Mutación , Síndrome de Marfan/genética , Síndrome de Marfan/patología , Fibrilina-1/genética , Células Madre Pluripotentes Inducidas/metabolismo , Humanos , Diferenciación Celular , Línea Celular , Masculino , Adipoquinas

RESUMEN

BACKGROUND: Thoracic aortic aneurysm (TAA) is associated with significant morbidity and mortality. Although individuals with family histories of TAA often undergo clinical molecular genetic testing, adults with nonsyndromic TAA are not typically evaluated for genetic causes. We sought to understand the genetic contribution of both germline and somatic mosaic variants in a cohort of adult individuals with nonsyndromic TAA at a single center. METHODS AND RESULTS: One hundred eighty-one consecutive patients <60 years who presented with nonsyndromic TAA at the Massachusetts General Hospital underwent deep (>500×) targeted sequencing across 114 candidate genes associated with TAA and its related functional pathways. Samples from 354 age- and sex-matched individuals without TAA were also sequenced, with a 2:1 matching. We found significant enrichments for germline (odds ratio [OR], 2.44, P=4.6×10-6 [95% CI, 1.67-3.58]) and also somatic mosaic variants (OR, 4.71, P=0.026 [95% CI, 1.20-18.43]) between individuals with and without TAA. Likely genetic causes were present in 24% with nonsyndromic TAA, of which 21% arose from germline variants and 3% from somatic mosaic alleles. The 3 most frequently mutated genes in our cohort were FLNA (encoding Filamin A), NOTCH3 (encoding Notch receptor 3), and FBN1 (encoding Fibrillin-1). There was increased frequency of both missense and loss of function variants in TAA individuals. CONCLUSIONS: Likely contributory dominant acting genetic variants were found in almost one quarter of nonsyndromic adults with TAA. Our findings suggest a more extensive genetic architecture to TAA than expected and that genetic testing may improve the care and clinical management of adults with nonsyndromic TAA.

Asunto(s)

Aneurisma de la Aorta Torácica , Predisposición Genética a la Enfermedad , Mutación de Línea Germinal , Mosaicismo , Humanos , Masculino , Femenino , Aneurisma de la Aorta Torácica/genética , Aneurisma de la Aorta Torácica/diagnóstico , Adulto , Persona de Mediana Edad , Receptor Notch3/genética , Fibrilina-1/genética , Estudios de Casos y Controles , Fenotipo , Filaminas/genética , Factores de Riesgo , Secuenciación de Nucleótidos de Alto Rendimiento , Adipoquinas

RESUMEN

Objective: To investigate the characteristics of posterior segment lesions in Marfan syndrome (MFS) patients and their relationship with anterior segment biometric parameters and FBN1 genotype. Methods: A cross-sectional study was conducted. A total of 121 MFS patients, 76 males and 45 females, with an average age of (11.72±11.66) years, who visited the Department of Ophthalmology, Eye & ENT Hospital of Fudan University from January 2013 to March 2023 were included. The presence of posterior scleral staphyloma was observed using B-mode ultrasound, and macular lesions were identified and classified using the atrophy-traction-neovascularization system based on ultra-widefield fundus images, color fundus images, and optical coherence tomography scans. Anterior segment biometric parameters, including axial length of the eye, average corneal curvature, corneal astigmatism, horizontal corneal diameter, anterior chamber depth, and lens thickness, were collected, and the direction and extent of lens dislocation were observed. Molecular genetic analysis of FBN1 gene mutations in patients was performed using next-generation sequencing based on a panel of ocular genetic diseases, and the impact of the genotype and anterior segment biometric parameters on the posterior segment manifestations was analyzed. Results: Sixty patients exhibited posterior segment lesions, including retinal detachment (4 cases, 3.31%), macular lesions (47 cases, 38.84%), and posterior scleral staphyloma (54 cases, 44.63%). There was statistically significant difference in axial length of the eye between patients with and without posterior scleral staphyloma [23.09 (22.24, 24.43) and 27.04 (25.44, 28.88) mm], between patients with and without macular lesions [23.16 (22.24, 24.61) and 27.04 (25.74, 28.78) mm], and between patients with and without atrophic macular lesions [23.16 (22.24, 24.61) and 27.04 (25.74, 28.79) mm] (all P<0.001). There was statistically significant difference in anterior chamber depth between patients with and without macular lesions [3.11 (2.75, 3.30) and 3.34 (3.09, 3.60) mm] (P<0.05). There was also statistically significant difference in corneal astigmatism between patients with and without posterior scleral staphyloma [2.15 (1.20, 2.93) and 1.40 (1.00, 2.20) diopters] (P<0.05). The location and region of the FBN1 gene mutation not only showed statistically significant difference from the positive rates of posterior scleral staphyloma and macular lesions (all P<0.05), but also influenced the occurrence of atrophic macular lesions (both P<0.05). Patients with FBN1 mutations located in the transforming growth factor ß regulatory sequence had the highest proportion of posterior scleral staphyloma and macular lesions (both 10/11). Conclusions: Posterior scleral staphyloma and macular lesions have a relatively high incidence in MFS patients and tend to progress to more severe grades. The age, axial length of the eye, anterior chamber depth, corneal astigmatism, and location and region of the FBN1 gene mutation are factors affecting the posterior segment lesions in MFS patients.

Asunto(s)

Fibrilina-1 , Genotipo , Síndrome de Marfan , Adolescente , Niño , Femenino , Humanos , Masculino , Adulto Joven , Adipoquinas , Segmento Anterior del Ojo , Biometría , Estudios Transversales , Fibrilina-1/genética , Degeneración Macular/genética , Síndrome de Marfan/genética , Mutación , Segmento Posterior del Ojo/patología , Recién Nacido , Lactante , Preescolar

RESUMEN

BACKGROUND: Marfan syndrome (MFS) is a hereditary connective tissue disorder involving multiple systems, including ophthalmologic abnormalities. Most cases are due to heterozygous mutations in the fibrillin-1 gene (FBN1). Other associated genes include LTBP2, MYH11, MYLK, and SLC2A10. There is significant clinical overlap between MFS and other Marfan-like disorders. PURPOSE: To expand the mutation spectrum of FBN1 gene and validate the pathogenicity of Marfan-related genes in patients with MFS and ocular manifestations. METHODS: We recruited 318 participants (195 cases, 123 controls), including 59 sporadic cases and 88 families. All patients had comprehensive ophthalmic examinations showing ocular features of MFS and met Ghent criteria. Additionally, 754 cases with other eye diseases were recruited. Panel-based next-generation sequencing (NGS) screened mutations in 792 genes related to inherited eye diseases. RESULTS: We detected 181 mutations with an 84.7% detection rate in sporadic cases and 87.5% in familial cases. The overall detection rate was 86.4%, with FBN1 accounting for 74.8%. In cases without FBN1 mutations, 23 mutations from seven Marfan-related genes were identified, including four pathogenic or likely pathogenic mutations in LTBP2. The 181 mutations included 165 missenses, 10 splicings, three frameshifts, and three nonsenses. FBN1 accounted for 53.0% of mutations. The most prevalent pathogenic mutation was FBN1 c.4096G>A. Additionally, 94 novel mutations were detected, with 13 de novo mutations in 14 families. CONCLUSION: We expanded the mutation spectrum of the FBN1 gene and provided evidence for the pathogenicity of other Marfan-related genes. Variants in LTBP2 may contribute to the ocular manifestations in MFS, underscoring its role in phenotypic diversity.

Asunto(s)

Fibrilina-1 , Secuenciación de Nucleótidos de Alto Rendimiento , Síndrome de Marfan , Mutación , Humanos , Síndrome de Marfan/genética , Síndrome de Marfan/patología , Femenino , Masculino , Fibrilina-1/genética , Adulto , Niño , Adolescente , Persona de Mediana Edad , Preescolar , Oftalmopatías/genética , Oftalmopatías/patología , Linaje , Pueblos del Este de Asia , Adipoquinas

RESUMEN

Fibrillin microfibrils play a critical role in the formation of elastic fibers, tissue/organ development, and cardiopulmonary function. These microfibrils not only provide structural support and flexibility to tissues, but they also regulate growth factor signaling through a plethora of microfibril-binding proteins in the extracellular space. Mutations in fibrillins are associated with human diseases affecting cardiovascular, pulmonary, skeletal, and ocular systems. Fibrillins consist of up to 47 epidermal growth factor-like repeats, of which more than half are modified by protein O-glucosyltransferase 2 (POGLUT2) and/or POGLUT3. Loss of these modifications reduces secretion of N-terminal fibrillin constructs overexpressed in vitro. Here, we investigated the role of POGLUT2 and POGLUT3 in vivo using a Poglut2/3 double knockout (DKO) mouse model. Blocking O-glucosylation caused neonatal death with skeletal, pulmonary, and eye defects reminiscent of fibrillin/elastin mutations. Proteomic analyses of DKO dermal fibroblast medium and extracellular matrix provided evidence that fibrillins were more sensitive to loss of O-glucose compared to other POGLUT2/3 substrates. This conclusion was supported by immunofluorescent analyses of late gestation DKO lungs where FBN levels were reduced and microfibrils appeared fragmented in the pulmonary arteries and veins, bronchioles, and developing saccules. Defects in fibrillin microfibrils likely contributed to impaired elastic fiber formation and histological changes observed in DKO lung blood vessels, bronchioles, and saccules. Collectively, these results highlight the importance of POGLUT2/3-mediated O-glucosylation in vivo and open the possibility that O-glucose modifications on fibrillin influence microfibril assembly and or protein interactions in the ECM environment.

Asunto(s)

Fibrilinas , Pulmón , Ratones Noqueados , Animales , Ratones , Animales Recién Nacidos , Matriz Extracelular/metabolismo , Matriz Extracelular/genética , Fibrilina-1/metabolismo , Fibrilina-1/genética , Fibrilinas/metabolismo , Fibrilinas/genética , Glicosilación , Pulmón/metabolismo , Pulmón/patología , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo

RESUMEN

Marfan Syndrome, a connective tissue disorder caused by Fibrillin-1 (FBN1) gene mutations, induces disease in the ocular, musculoskeletal, and cardiovascular systems and increases aortic vulnerability to rupture associated with high mortality rates. We describe an induced pluripotent stem cell line (HFD1) generated from patient-derived human dermal fibroblasts harboring a heterozygous c.3338-2A>C intronic splice acceptor site variant preceding Exon 28 of FBN1. The clonal line, which produces abnormal FBN1 splice variants, has a normal karyotype, expresses appropriate stemness markers, and maintains trilineage differentiation potential. This line represents a valuable resource for studying how abnormal splicing variants contribute to Marfan Syndrome.

Asunto(s)

Células Madre Pluripotentes Inducidas , Intrones , Síndrome de Marfan , Humanos , Síndrome de Marfan/genética , Síndrome de Marfan/patología , Células Madre Pluripotentes Inducidas/metabolismo , Línea Celular , Empalme del ARN , Fibrilina-1/genética , Diferenciación Celular

Asunto(s)

Síndrome de Marfan , Mastocitos , Piel , Humanos , Mastocitos/inmunología , Síndrome de Marfan/patología , Síndrome de Marfan/diagnóstico , Piel/patología , Piel/inmunología , Tejido Conectivo/patología , Fibrilina-1/genética , Fibrilina-1/metabolismo

RESUMEN

BACKGROUND: congenital diaphragmatic hernia (CDH) is a birth defect occurring in isolated or syndromic (chromosomal or monogenic) conditions. The diaphragmatic defect can be the most common one: left-sided posterolateral, named Bochdalek hernia; or it can be an anterior-retrosternal defect, named Morgagni hernia. Marfan syndrome (MFS) is a rare autosomal dominant inherited condition that affects connective tissue, caused by mutations in fibrillin-1 gene on chromosome 15. To date various types of diaphragmatic defects (about 30 types) have been reported in association with MFS, but they are heterogeneous, including CDH and paraesophageal hernia. CASE PRESENTATION: We describe the case of a child incidentally diagnosed with Morgagni hernia through a chest X-ray performed due to recurrent respiratory tract infections. Since the diagnosis of CDH, the patient underwent a clinical multidisciplinary follow-up leading to the diagnosis of MFS in accordance with revised Ghent Criteria: the child had typical clinical features and a novel heterozygous de novo single-base deletion in exon 26 of the FBN1 gene, identified by Whole-Exome Sequencing. MFS diagnosis permitted to look for cardiovascular complications and treat them, though asymptomatic, in order to prevent major cardiovascular life-threatening events. CONCLUSION: Our case shows the importance of a long-term and multidisciplinary follow-up in all children with diagnosis of CDH.

Asunto(s)

Fibrilina-1 , Hernias Diafragmáticas Congénitas , Síndrome de Marfan , Humanos , Adipoquinas , Fibrilina-1/genética , Estudios de Seguimiento , Hernias Diafragmáticas Congénitas/complicaciones , Síndrome de Marfan/complicaciones , Síndrome de Marfan/diagnóstico , Síndrome de Marfan/genética , Niño

RESUMEN

Fibrillin-1 and fibrillin-2, encoded by FBN1 and FBN2, respectively, play significant roles in elastic fiber assembly, with pathogenic variants causing a diverse group of connective tissue disorders such as Marfan syndrome (MFS) and congenital contractural arachnodactyly (CCD). Different genomic variations may lead to heterogeneous phenotypic features and functional consequences. Recent high-throughput sequencing modalities have allowed detection of novel variants that may guide the care for patients and inform the genetic counseling for their families. We performed clinical phenotyping for two newborn infants with complex congenital heart defects. For genetic investigations, we employed next-generation sequencing strategies including whole-genome Single-Nucleotide Polymorphism (SNP) microarray for infant A with valvular insufficiency, aortic sinus dilatation, hydronephrosis, and dysmorphic features, and Trio whole-exome sequencing (WES) for infant B with dextro-transposition of the great arteries (D-TGA) and both parents. Infant A is a term male with neonatal marfanoid features, left-sided hydronephrosis, and complex congenital heart defects including tricuspid regurgitation, aortic sinus dilatation, patent foramen ovale, patent ductus arteriosus, mitral regurgitation, tricuspid regurgitation, aortic regurgitation, and pulmonary sinus dilatation. He developed severe persistent pulmonary hypertension and worsening acute hypercapnic hypoxemic respiratory failure, and subsequently expired on day of life (DOL) 10 after compassionate extubation. Cytogenomic whole-genome SNP microarray analysis revealed a deletion within the FBN1 gene spanning exons 7-30, which overlapped with the exon deletion hotspot region associated with neonatal Marfan syndrome. Infant B is a term male prenatally diagnosed with isolated D-TGA. He required balloon atrial septostomy on DOL 0 and subsequent atrial switch operation, atrial septal defect repair, and patent ductus arteriosus ligation on DOL 5. Trio-WES revealed compound heterozygous c.518C>T and c.8230T>G variants in the FBN2 gene. Zygosity analysis confirmed each of the variants was inherited from one of the parents who were healthy heterozygous carriers. Since his cardiac repair at birth, he has been growing and developing well without any further hospitalization. Our study highlights novel FBN1/FBN2 variants and signifies the phenotype-genotype association in two infants affected with complex congenital heart defects with and without dysmorphic features. These findings speak to the importance of next-generation high-throughput genomics for novel variant detection and the phenotypic variability associated with FBN1/FBN2 variants, particularly in the neonatal period, which may significantly impact clinical care and family counseling.

Asunto(s)

Fibrilina-1 , Fibrilina-2 , Cardiopatías Congénitas , Síndrome de Marfan , Humanos , Fibrilina-1/genética , Síndrome de Marfan/genética , Fibrilina-2/genética , Masculino , Recién Nacido , Cardiopatías Congénitas/genética , Secuenciación de Nucleótidos de Alto Rendimiento , Femenino , Polimorfismo de Nucleótido Simple , Mutación , Genómica/métodos , Fenotipo , Secuenciación del Exoma , Adipoquinas

RESUMEN

Microfibril-associated glycoprotein 4 (MFAP4) is a 36-kDa extracellular matrix glycoprotein with critical roles in organ fibrosis, chronic obstructive pulmonary disease, and cardiovascular disorders, including aortic aneurysms. MFAP4 multimerises and interacts with elastogenic proteins, including fibrillin-1 and tropoelastin, and with cells via integrins. Structural details of MFAP4 and its potential interfaces for these interactions are unknown. Here, we present a cryo-electron microscopy structure of human MFAP4. In the presence of calcium, MFAP4 assembles as an octamer, where two sets of homodimers constitute the top and bottom halves of each octamer. Each homodimer is linked together by an intermolecular disulphide bond. A C34S missense mutation prevents disulphide-bond formation between monomers but does not prevent octamer assembly. The atomic model, built into the 3.55 Å cryo-EM map, suggests that salt-bridge interactions mediate homodimer assembly, while non-polar residues form the interface between octamer halves. In the absence of calcium, an MFAP4 octamer dissociates into two tetramers. Binding studies with fibrillin-1, tropoelastin, LTBP4, and small fibulins show that MFAP4 has multiple surfaces for protein-protein interactions, most of which depend upon MFAP4 octamer assembly. The C34S mutation does not affect these protein interactions or cell interactions. MFAP4 assemblies with fibrillin-1 abrogate MFAP4 interactions with cells.

Asunto(s)

Microscopía por Crioelectrón , Proteínas de la Matriz Extracelular , Fibrilina-1 , Microfibrillas , Tropoelastina , Humanos , Adipoquinas , Calcio/metabolismo , Proteínas de la Matriz Extracelular/metabolismo , Proteínas de la Matriz Extracelular/química , Proteínas de la Matriz Extracelular/genética , Fibrilina-1/metabolismo , Fibrilina-1/genética , Fibrilina-1/química , Glicoproteínas , Células HEK293 , Microfibrillas/metabolismo , Microfibrillas/química , Microfibrillas/ultraestructura , Modelos Moleculares , Mutación Missense , Unión Proteica , Multimerización de Proteína , Tropoelastina/metabolismo , Tropoelastina/química , Tropoelastina/genética

RESUMEN

The cardinal phenotypic hallmarks of Marfan syndrome (MFS) include cardiac, ocular, and skeletal abnormalities. Since the clinical phenotype of MFS is highly heterogeneous, with certain symptoms appearing as children age, the diagnostic process and establishing a genotype-phenotype association in childhood MFS can be challenging. The lack of sufficient childhood studies also makes it difficult to interpret the subject. This study aims to evaluate the relationship between clinical symptoms used as diagnostic criteria and FBN1 variations in children with MFS. This study investigated the relationships between genotypes and phenotypes in 131 children suspected of having Marfan syndrome (MFS). Diagnosis of MFS was made according to the revised Ghent nosology. FBN1 variants were categorized based on exon regions, type of variant, and pathogenicity classes. These FBN1 variants were then correlated with the clinical manifestations including cardiovascular, ocular, facial, and skeletal abnormalities. Out of the children, 43 were diagnosed with MFS. FBN1 variant was identified in 32 (74.4%) of the MFS children. MFS diagnosis could not be made in five (15.6%) FBN1 variant-positive children. The most common cardinal finding is cardiac anomalies n = 38 (88.3%). The most common FBN1 pathogenic variant was c.1786 T > C/p.Cys596Arg n = 4 (12.5%). The distribution of pathogenic variants was as follows: 29 (90.6%) missense, 2 (6.3%) frameshift, and 1 (3.1%) nonsense. The numbers of AD and EL of the variant-positive children were 16 (50%) and 14 (43.7%), respectively. Ocular abnormalities were more common in children with FBN1-positive MFS (p = 0.009). There was no difference in the number of cardiac abnormalities between FBN1-positive and FBN1-negative MFS patients (p = 0.139).   Conclusion: This study examines the relationship between FBN1 variants and clinical features used as diagnostic criteria in MFS children. The findings emphasize the importance of long-term monitoring of heterogeneous clinical phenotypes and bioinformatic reanalysis in determining the genotype-phenotype relationship in children, as MFS symptoms can vary with age. What is Known: • Marfan syndrome has highly variable phenotypic heterogeneity. • The genotype-phenotype relationship in childhood Marfan syndrome is not clear enough due to the variation in the time of onset of the findings. What is New: • This article provides regional data for the field of research on genotype-phenotype relationships in childhood Marfan syndrome. • Long-term follow-up of clinical findings and bioinformatics reanalysis is an important requirement for a well-established genotype-phenotype relationship in childhood Marfan syndrome.

Asunto(s)

Fibrilina-1 , Genotipo , Síndrome de Marfan , Fenotipo , Humanos , Síndrome de Marfan/genética , Síndrome de Marfan/diagnóstico , Niño , Femenino , Masculino , Fibrilina-1/genética , Preescolar , Adolescente , Turquía/epidemiología , Lactante , Estudios de Asociación Genética , Mutación , Adipoquinas

RESUMEN

BACKGROUND: Marfan syndrome (MFS) is an autosomal dominant connective tissue disease with wide clinical heterogeneity, and mainly caused by pathogenic variants in fibrillin-1 (FBN1). METHODS: A Chinese 4-generation MFS pedigree with 16 family members was recruited and exome sequencing (ES) was performed in the proband. Transcript analysis (patient RNA and minigene assays) and in silico structural analysis were used to determine the pathogenicity of the variant. In addition, germline mosaicism in family member (Ι:1) was assessed using quantitative fluorescent polymerase chain reaction (QF-PCR) and short tandem repeat PCR (STR) analyses. RESULTS: Two cis-compound benign intronic variants of FBN1 (c.3464-4 A > G and c.3464-5G > A) were identified in the proband by ES. As a compound variant, c.3464-5_3464-4delGAinsAG was found to be pathogenic and co-segregated with MFS. RNA studies indicated that aberrant transcripts were found only in patients and mutant-type clones. The variant c.3464-5_3464-4delGAinsAG caused erroneous integration of a 3 bp sequence into intron 28 and resulted in the insertion of one amino acid in the protein sequence (p.Ile1154_Asp1155insAla). Structural analyses suggested that p.Ile1154_Asp1155insAla affected the protein's secondary structure by interfering with one disulfide bond between Cys1140 and Cys1153 and causing the extension of an anti-parallel ß sheet in the calcium-binding epidermal growth factor-like (cbEGF)13 domain. In addition, the asymptomatic family member Ι:1 was deduced to be a gonadal mosaic as assessed by inconsistent results of sequencing and STR analysis. CONCLUSIONS: To our knowledge, FBN1 c.3464-5_3464-4delGAinsAG is the first identified pathogenic intronic indel variant affecting non-canonical splice sites in this gene. Our study reinforces the importance of assessing the pathogenic role of intronic variants at the mRNA level, with structural analysis, and the occurrence of mosaicism.

Asunto(s)

Fibrilina-1 , Intrones , Síndrome de Marfan , Mosaicismo , Linaje , Humanos , Fibrilina-1/genética , Síndrome de Marfan/genética , Síndrome de Marfan/patología , Femenino , Masculino , Adulto , Intrones/genética , Mutación INDEL/genética , Persona de Mediana Edad , Adipoquinas

RESUMEN

Phenotype transformation of vascular smooth muscle cells (VSMCs) plays an important role in the development of atherosclerosis. Asprosin is a newly discovered adipokine, which is critical in regulating metabolism. However, the relationship between asprosin and phenotype transformation of VSMCs in atherosclerosis remains unclear. The aim of this study is to investigate whether asprosin affects the progression of atherosclerosis by inducing phenotype transformation of VSMCs. We established an atherosclerosis model in ApoE-/- mice and administered asprosin recombinant protein and asprosin antibody to mice. Knocking down asprosin was also as an intervention. Interestingly, we found a correlation between asprosin levels and atherosclerosis. Asprosin promoted plaque formation and phenotype transformation of VSMCs. While, AspKD or asprosin antibody reduced the plaque lesion and suppressed vascular stiffness in ApoE-/- mice. Mechanistically, asprosin induced phenotype transformation of MOVAs by binding to GPR54, leading to Gαq/11 recruitment and activation of the PLC-PKC-ERK1/2-STAT3 signaling pathway. Si GPR54 or GPR54 antagonist partially inhibited the action of asprosin in MOVAs. Mutant GPR54-(267, 307) residue cancelled the binding of asprosin and GPR54. In summary, this study confirmed asprosin activated GPR54/Gαq/11-dependent ERK1/2-STAT3 signaling pathway, thereby promoting VSMCs phenotype transformation and aggravating atherosclerosis, thus providing a new target for the treatment of atherosclerosis.

Asunto(s)

Aterosclerosis , Músculo Liso Vascular , Miocitos del Músculo Liso , Fenotipo , Animales , Aterosclerosis/metabolismo , Aterosclerosis/patología , Aterosclerosis/genética , Músculo Liso Vascular/metabolismo , Músculo Liso Vascular/patología , Ratones , Miocitos del Músculo Liso/metabolismo , Miocitos del Músculo Liso/patología , Fibrilina-1/metabolismo , Fibrilina-1/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/genética , Masculino , Transducción de Señal , Modelos Animales de Enfermedad , Apolipoproteínas E/deficiencia , Apolipoproteínas E/genética , Apolipoproteínas E/metabolismo , Humanos , Proteínas de la Matriz Extracelular/metabolismo , Proteínas de la Matriz Extracelular/genética , Ratones Noqueados