Thoracic aortic-aneurysm and dissection in association with significant mitral valve disease caused by mutations in TGFB2

Advances and Challenges in Targeting TGF-β Isoforms for Therapeutic Intervention of Cancer: A Mechanism-Based Perspective

The TGF-β family is a group of 25 kDa secretory cytokines, in mammals consisting of three dimeric isoforms (TGF-βs 1, 2, and 3), each encoded on a separate gene with unique regulatory elements. Each isoform plays unique, diverse, and pivotal roles in cell growth, survival, immune response, and differentiation. However, many researchers in the TGF-β field often mistakenly assume a uniform functionality among all three isoforms. Although TGF-βs are essential for normal development and many cellular and physiological processes, their dysregulated expression contributes significantly to various diseases. Notably, they drive conditions like fibrosis and tumor metastasis/progression. To counter these pathologies, extensive efforts have been directed towards targeting TGF-βs, resulting in the development of a range of TGF-β inhibitors. Despite some clinical success, these agents have yet to reach their full potential in the treatment of cancers. A significant challenge rests in effectively targeting TGF-βs' pathological functions while preserving their physiological roles. Many existing approaches collectively target all three isoforms, failing to target just the specific deregulated ones. Additionally, most strategies tackle the entire TGF-β signaling pathway instead of focusing on disease-specific components or preferentially targeting tumors. This review gives a unique historical overview of the TGF-β field often missed in other reviews and provides a current landscape of TGF-β research, emphasizing isoform-specific functions and disease implications. The review then delves into ongoing therapeutic strategies in cancer, stressing the need for more tools that target specific isoforms and disease-related pathway components, advocating mechanism-based and refined approaches to enhance the effectiveness of TGF-β-targeted cancer therapies.

Brachyolmia, dental anomalies and short stature (DASS): Phenotype and genotype analyses of Egyptian and Pakistani patients

Brachyolmia is a heterogeneous group of developmental disorders characterized by a short trunk, short stature, scoliosis, and generalized platyspondyly without significant deformities in the long bones. DASS (Dental Abnormalities and Short Stature), caused by alterations in the LTBP3 gene, was previously considered as a subtype of brachyolmia. The present study investigated three unrelated consanguineous families (A, B, C) with Brachyolmia and DASS from Egypt and Pakistan. In our Egyptian patients, we also observed hearing impairment. Exome sequencing was performed to determine the genetic causes of the diverse clinical conditions in the patients. Exome sequencing identified a novel homozygous splice acceptor site variant (LTBP3:c.3629-1G > T; p. ?) responsible for DASS phenotypes and a known homozygous missense variant (CABP2: c.590T > C; p.Ile197Thr) causing hearing impairment in the Egyptian patients. In addition, two previously reported homozygous frameshift variants (LTBP3:c.132delG; p.Pro45Argfs*25) and (LTBP3:c.2216delG; p.Gly739Alafs*7) were identified in Pakistani patients. This study emphasizes the vital role of LTBP3 in the axial skeleton and tooth morphogenesis and expands the mutational spectrum of LTBP3. We are reporting LTBP3 variants in seven patients of three families, majorly causing brachyolmia with dental and cardiac anomalies. Skeletal assessment documented short webbed neck, broad chest, evidences of mild long bones involvement, short distal phalanges, pes planus and osteopenic bone texture as additional associated findings expanding the clinical phenotype of DASS. The current study reveals that the hearing impairment phenotype in Egyptian patients of family A has a separate transmission mechanism independent of LTBP3.

2022 ACC/AHA guideline for the diagnosis and management of aortic disease: A report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Unraveling the role of TGFβ signaling in thoracic aortic aneurysm and dissection using Fbn1 mutant mouse models

Although abnormal TGFβ signaling is observed in several heritable forms of thoracic aortic aneurysms and dissections including Marfan syndrome, its precise role in aortic disease progression is still disputed. Using a mouse genetic approach and quantitative isobaric labeling proteomics, we sought to elucidate the role of TGFβ signaling in three Fbn1 mutant mouse models representing a range of aortic disease from microdissection (without aneurysm) to aneurysm (without rupture) to aneurysm and rupture. Results indicated that reduced TGFβ signaling and increased mast cell proteases were associated with microdissection. In contrast, increased abundance of extracellular matrix proteins, which could be reporters for positive TGFβ signaling, were associated with aneurysm. Marked reductions in collagens and fibrillins, and increased TGFβ signaling, were associated with aortic rupture. Our data indicate that TGFβ signaling performs context-dependent roles in the pathogenesis of thoracic aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate. Structure: Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Anti-TGF-β1 aptamer enhances therapeutic effect of tyrosine kinase inhibitor, gefitinib, on non-small cell lung cancer in xenograft model

Transforming growth factor β (TGF-β) is a multifunctional cytokine that plays crucial pathophysiological roles in various diseases, such as cancer and fibrosis. However, the disease modulation by targeting TGF-β1 isoform remains to be established, regardless of several studies employed with limited antibodies. Here, we developed an RNA aptamer to human active TGF-β1, named APT-β1, and characterized its properties in vitro and in vivo. APT-β1 bound to human and mouse active TGF-β1 proteins with high affinity and specificity and strongly inhibited TGF-β1-induced downstream signaling and cell morphology with 50% inhibition concentration (IC50) values at picomolar concentrations. In a xenograft mouse model of non-small cell lung cancer, APT-β1 alone showed no appreciable effect on tumor growth, while it greatly enhanced the anti-tumor effect of gefitinib, an approved tyrosine kinase inhibitor. These findings strongly suggest that the anti-TGF-β1 medication may be a promising cancer therapy to suppress repopulation of lung cancer in combination with certain anti-cancer drugs, such as gefitinib.

Expanding genotypic and phenotypic spectrums of LTBP3 variants in dental anomalies and short stature syndrome

Mutations in LTBP3 are associated with Dental Anomalies and Short Stature syndrome (DASS; MIM 601216), which is characterized by hypoplastic type amelogenesis imperfecta, hypodontia, underdeveloped maxilla, short stature, brachyolmia, aneurysm and dissection of the thoracic aorta. Here we report a novel (p.Arg545ProfsTer22) and a recurrent (c.3107-2A > G) LTBP3 variants, in a Turkish family affected with DASS. The proband, who carried compound heterozygous variant c.3107-2A > G, p.Arg545ProfsTer22, was most severely affected with DASS. The proband's father, who carried the heterozygous variant c.3107-2A > G had short stature and prognathic mandible. The mother and brother of the proband carried the heterozygous variant p.Arg545ProfsTer22, but only the mother showed any DASS characteristics. The c.3107-2A > G and the p.Arg545ProfsTer22 variants are expected to result in abnormal LTPB3 protein, failure of TGFβ-LAP-LTBP3 complex formation, and subsequent disruption of TGFβ secretion and activation. This is the first report of heterozygous carriers of LTBP3 variants showing phenotypes. The new findings of DASS found in this family include taurodontism, single-rooted molars, abnormal dentin, calcified dental pulp blood vessels, prognathic mandible, failure of mandibular tooth eruption, interatrial septal aneurysm, secundum atrial septal defect, tricuspid valve prolapse, and a recurrent glenohumeral joint dislocation.

Genetics of Heritable Thoracic Aortic Disease

Genetic testing plays an increasing diagnostic and prognostic role in the management of patients with heritable thoracic aortic disease (HTAD). The identification of a specific variant can establish or confirm the diagnosis of syndromic HTAD, dictate extensive evaluation of the arterial tree in HTAD with known distal vasculature involvement and justify closer follow-up and earlier surgical intervention in HTAD with high risk of dissection of minimal or normal aortic size. Evolving phenotype–genotype correlations lead us towards more precise and individualized management and treatment of patients with HTAD. In this review, we present the latest evidence regarding the role of genetics in patients with HTAD.

The Heart Muscle and Valve Involvement in Marfan Syndrome, Loeys-Dietz Syndromes, and Collagenopathies

The inherited connective tissue disorders (Marfan syndrome, Loeys-Dietz syndrome [LDS], and Ehlers-Danlos syndrome [EDS]) involve connective tissue of various organ systems. These pathologies share many common features, nonetheless compared to Marfan syndrome, LDS' cardiovascular manifestations tend to be more severe. In contrast, no association is reported between LDS and the presence of ectopia lentis. The EDS are currently classified into thirteen subtypes. There is substantial symptoms overlap between the EDS subtypes, and they are associated with an increased incidence of cardiovascular abnormalities, such as mitral valve prolapse and aortic dissection.

Loeys-Dietz syndrome and isolated severe ostial left main coronary stenosis presenting as ventricular fibrillation arrest and biventricular takotsubo syndrome in a 25-year-old patient

We present the case of a previously healthy 25-year-old woman who presented with an out-of-hospital ventricular fibrillation arrest. Postresuscitation ECG did not show any evidence of ST segment elevation. Echocardiogram showed regional wall abnormalities in keeping with takotsubo syndrome (TTS). Urgent coronary angiogram to rule out malignant congenital coronary artery anomaly revealed an isolated severe ostial left main coronary artery (LMCA) stenosis, a rare disease, approximately 0.2% in previous case series. The LMCA was aneurysmal. Genetic studies revealed a novel frameshift pathogenic variant in the transforming growth factor B two ligand gene (TGFB2) gene, suggestive of Loeys-Dietz syndrome (LDS) type 4, an aggressive vascular disease. Ostial LMCA stenosis has not been previously reported in LDS, and we outline the management of this unique disease combination. We also reflect on its presentation as TTS and infer that TTS and acute coronary syndromes are not mutually exclusive.

Genetics Evaluation of Targeted Exome Sequencing in 223 Chinese Probands With Genetic Skeletal Dysplasias

Genetic skeletal dysplasias (GSDs) are a type of disease with complex phenotype and high heterogeneity, characterized by cartilage and bone growth abnormalities. The variable phenotypes of GSD make clinical diagnosis difficult. To explore the clinical utility of targeted exome sequencing (TES) in the diagnosis of GSD, 223 probands with suspected GSD were enrolled for TES with a panel of 322 known disease-causing genes. After bioinformatics analysis, all candidate variants were prioritized by pathogenicity. Sanger sequencing was used to verify candidate variants in the probands and parents and to trace the source of variants in family members. We identified the molecular diagnoses for 110/223 probands from 24 skeletal disorder groups and confirmed 129 pathogenic/likely pathogenic variants in 48 genes. The overall diagnostic rate was 49%. The molecular diagnostic results modified the diagnosis in 25% of the probands, among which mucopolysaccharidosis and spondylo-epi-metaphyseal dysplasias were more likely to be misdiagnosed. The clinical management of 33% of the probands also improved; 21 families received genetic counseling; 4 families accepted prenatal genetic diagnosis, 1 of which was detected to carry pathogenic variants. The results showed that TES achieved a high diagnostic rate for GSD, helping clinicians confirm patients’ molecular diagnoses, formulate treatment directions, and carry out genetic counseling. TES could be an economical diagnostic method for patients with GSD.

Therapeutic targeting of TGF-β in cancer: hacking a master switch of immune suppression

Cancers may escape elimination by the host immune system by rewiring the tumour microenvironment towards an immune suppressive state. Transforming growth factor-β (TGF-β) is a secreted multifunctional cytokine that strongly regulates the activity of immune cells while, in parallel, can promote malignant features such as cancer cell invasion and migration, angiogenesis, and the emergence of cancer-associated fibroblasts. TGF-β is abundantly expressed in cancers and, most often, its abundance associated with poor clinical outcomes. Immunotherapeutic strategies, particularly T cell checkpoint blockade therapies, so far, only produce clinical benefit in a minority of cancer patients. The inhibition of TGF-β activity is a promising approach to increase the efficacy of T cell checkpoint blockade therapies. In this review, we briefly outline the immunoregulatory functions of TGF-β in physiological and malignant contexts. We then deliberate on how the therapeutic targeting of TGF-β may lead to a broadened applicability and success of state-of-the-art immunotherapies.

Selective inhibition of TGFβ1 activation overcomes primary resistance to checkpoint blockade therapy by altering tumor immune landscape

Despite breakthroughs achieved with cancer checkpoint blockade therapy (CBT), many patients do not respond to anti-programmed cell death-1 (PD-1) due to primary or acquired resistance. Human tumor profiling and preclinical studies in tumor models have recently uncovered transforming growth factor-β (TGFβ) signaling activity as a potential point of intervention to overcome primary resistance to CBT. However, the development of therapies targeting TGFβ signaling has been hindered by dose-limiting cardiotoxicities, possibly due to nonselective inhibition of multiple TGFβ isoforms. Analysis of mRNA expression data from The Cancer Genome Atlas revealed that TGFΒ1 is the most prevalent TGFβ isoform expressed in many types of human tumors, suggesting that TGFβ1 may be a key contributor to primary CBT resistance. To test whether selective TGFβ1 inhibition is sufficient to overcome CBT resistance, we generated a high-affinity, fully human antibody, SRK-181, that selectively binds to latent TGFβ1 and inhibits its activation. Coadministration of SRK-181-mIgG1 and an anti-PD-1 antibody in mice harboring syngeneic tumors refractory to anti-PD-1 treatment induced profound antitumor responses and survival benefit. Specific targeting of TGFβ1 was also effective in tumors expressing more than one TGFβ isoform. Combined SRK-181-mIgG1 and anti-PD-1 treatment resulted in increased intratumoral CD8⁺ T cells and decreased immunosuppressive myeloid cells. No cardiac valvulopathy was observed in a 4-week rat toxicology study with SRK-181, suggesting that selectively blocking TGFβ1 activation may avoid dose-limiting toxicities previously observed with pan-TGFβ inhibitors. These results establish a rationale for exploring selective TGFβ1 inhibition to overcome primary resistance to CBT.

TGFβ1 neutralization displays therapeutic efficacy through both an immunomodulatory and a non-immune tumor-intrinsic mechanism

BACKGROUND

Transforming growth factor-β (TGFβ) is emerging as a promising target for cancer therapy, given its ability to promote progression of advanced tumors and to suppress anti-tumor immune responses. However, TGFβ also plays multiple roles in normal tissues, particularly during organogenesis, raising toxicity concerns about TGFβ blockade. Dose-limiting cardiovascular toxicity was observed, possibly due to the blockade of all three TGFβ isoforms. The dominant isoform in tumors is TGFβ1, while TGFβ2 and TGFβ3 seem to be more involved in cardiovascular development. Recent data indicated that selective targeting of TGFβ1 promoted the efficacy of checkpoint inhibitor anti-PD1 in transplanted preclinical tumor models, without cardiovascular toxicity.

METHODS

To further explore the therapeutic potential of isoform-specific TGFβ blockade, we developed neutralizing mAbs targeting mature TGFβ1 or TGFβ3, and tested them, in parallel with anti-panTGFβ mAb 1D11, in two preclinical models: the transplanted colon cancer model CT26, and the autochthonous melanoma model TiRP.

RESULTS

We observed that the blockade of TGFβ1, but not that of TGFβ3, increased the efficacy of a prophylactic cellular vaccine against colon cancer CT26. This effect was similar to pan-TGFβ blockade, and was associated with increased infiltration of activated CD8 T cells in the tumor, and reduced levels of regulatory T cells and myeloid-derived suppressor cells. In contrast, in the autochthonous TiRP melanoma model, we observed therapeutic efficacy of the TGFβ1-specific mAb as a single agent, while the TGFβ3 mAb was inactive. In this model, the anti-tumor effect of TGFβ1 blockade was tumor intrinsic rather than immune mediated, as it was also observed in T-cell depleted mice. Mechanistically, TGFβ1 blockade increased mouse survival by delaying the phenotype switch, akin to epithelial-to-mesenchymal transition (EMT), which transforms initially pigmented tumors into highly aggressive unpigmented tumors.

CONCLUSIONS

Our results confirm TGFβ1 as the relevant isoform to target for cancer therapy, not only in combination with checkpoint inhibitors, but also with other immunotherapies such as cancer vaccines. Moreover, TGFβ1 blockade can also act as a monotherapy, through a tumor-intrinsic effect blocking the EMT-like transition. Because human melanomas that resist therapy often express a gene signature that links TGFβ1 with EMT-related genes, these results support the clinical development of TGFβ1-specific mAbs in melanoma.

Thoracic aortic aneurysm gene dictionary

Thoracic aortic aneurysm is typically clinically silent, with a natural history of progressive enlargement until a potentially lethal complication such as rupture or dissection occurs. Underlying genetic predisposition strongly influences the risk of thoracic aortic aneurysm and dissection. Familial cases are more virulent, have a higher rate of aneurysm growth, and occur earlier in life. To date, over 30 genes have been associated with syndromic and non-syndromic thoracic aortic aneurysm and dissection. The causative genes and their specific variants help to predict the disease phenotype, including age at presentation, risk of dissection at small aortic sizes, and risk of other cardiovascular and systemic manifestations. This genetic "dictionary" is already a clinical reality, allowing us to personalize care based on specific causative mutations for a substantial proportion of these patients. Widespread genetic sequencing of thoracic aortic aneurysm and dissection patients has been and continues to be crucial to the rapid expansion of this dictionary and ultimately, the delivery of truly personalized care to every patient.

Genes Associated with Thoracic Aortic Aneurysm and Dissection: 2019 Update and Clinical Implications

Thoracic aortic aneurysm is a typically silent disease characterized by a lethal natural history. Since the discovery of the familial nature of thoracic aortic aneurysm and dissection (TAAD) almost 2 decades ago, our understanding of the genetics of this disorder has undergone a transformative amplification. To date, at least 37 TAAD-causing genes have been identified and an estimated 30% of the patients with familial nonsyndromic TAAD harbor a pathogenic mutation in one of these genes. In this review, we present our yearly update summarizing the genes associated with TAAD and the ensuing clinical implications for surgical intervention. Molecular genetics will continue to bolster this burgeoning catalog of culprit genes, enabling the provision of personalized aortic care.

Bicuspid Aortic Valve: An Update in Morphology, Genetics, Biomarker, Complications, Imaging Diagnosis and Treatment

The bicuspid aortic valve, a kind of heart disease that comes from parents, has been paid attention around the world. Although most bicuspid aortic valve (BAV) patients will suffer from some complications including aortic stenosis, aortic regurgitation, endocarditis, and heart dysfunction in the late stage of the disease, there is none symptom in the childhood, which restrains us to diagnose and treatment in the onset phase of BAV. Hemodynamic abnormalities induced by the malformations of the valves in BAV patients for a long time will cause BAV-associated aortopathy: including progress aortic dilation, aneurysm, dissection and rupture, cardiac cyst and even sudden death. At present, preventive surgical intervention is the only effective method used in this situation and the diameter of the aorta is the primary reference criterion for surgery. And the treatment effects are always not satisfactory for patients and clinicians. Therefore, we need more methods to evaluate the progression of BAV and the surgery value and the appropriate intervention time by combining basic research with clinical treatment. In this review, advances in morphology, genetic, biomarkers, diagnosis and treatments are summarized, which expects to provide an update about BAV. It is our supreme expectations to provide some evidences for BAV early screening and diagnosis, and in our opinion, personalized surgical strategy is the trend of future BAV treatment.

Dysregulation of schizophrenia-related aquaporin 3 through disruption of paranode influences neuronal viability

Myelinated axons segregate the axonal membrane into four defined regions: the node of Ranvier, paranode, juxtaparanode, and internode. The paranodal junction consists of specific component proteins, such as neurofascin155 (NF155) on the glial side, and Caspr and Contactin on the axonal side. Although paranodal junctions are thought to play crucial roles in rapid saltatory conduction and nodal assembly, the role of their interaction with neurons is not fully understood. In a previous study, conditional NF155 knockout in oligodendrocytes led to disorganization of the paranodal junctions. To examine if disruption of paranodal junctions affects neuronal gene expression, we prepared total RNA from the retina of NF155 conditional knockout, and performed expression analysis. We found that the expression level of 433 genes changed in response to paranodal junction ablation. Interestingly, expression of aquaporin 3 (AQP3) was significantly reduced in NF155 conditional knockout mice, but not in cerebroside sulfotransferase knockout (CST-KO) mice, whose paranodes are not originally formed during development. Copy number variations have an important role in the etiology of schizophrenia (SCZ). We observed rare duplications of AQP3 in SCZ patients, suggesting a correlation between abnormal AQP3 expression and SCZ. To determine if AQP3 over-expression in NF155 conditional knockout mice influences neuronal function, we performed adeno-associated virus (AAV)-mediated over-expression of AQP3 in the motor cortex of mice and found a significant increase in caspase 3-dependent neuronal apoptosis in AQP3-transduced cells. This study may provide new insights into therapeutic approaches for SCZ by regulating AQP3 expression, which is associated with paranodal disruption.

Cytokines in aortic dissection

Aortic dissection (AD) is one of the most dangerous forms of vascular disease, characterized by endometrial rupture and intramural hematoma formation. Generally, the pathological process is complicated and closely related to the infiltration of inflammatory cells into the aortic wall and apoptosis of vascular smooth muscle cells. Currently, multiple cytokines, including interleukins, interferon, the tumor necrosis factor superfamily, colony stimulating factor, chemotactic factor, growth factor and so on, have all been demonstrated to play a critical role in AD. Additionally, studies of the link between cytokines and AD could deepen our understanding of the disease and may guide future treatment therapies; therefore, this review focuses on the role of cytokines in AD.

Human aortic aneurysm genomic dictionary: is it possible?

Thoracic aortic aneurysm (TAA), a typically silent but frequently lethal disease, is strongly influenced by underlying genetics. Approximately 30 genes have been associated with syndromic and non-syndromic familial thoracic aortic aneurysm and dissection (TAAD) to date. An estimated 30% of patients with non-syndromic familial TAAD, which is typically inherited in an autosomal dominant manner, have a mutation in one of these genes. The underlying genetic mutation helps predict patients' clinical presentation, risk of aortic dissection at small aortic sizes (< 5.0 cm), and risk of other cardiovascular disease. As a result, a TAAD genomic dictionary based on these genes is necessary to provide optimal patient care, but is not on its own sufficient as this disease is typically inherited with reduced penetrance and has widely variable expressivity. Next-generation sequencing has been and will continue to be critical for identifying novel genes and variants associated with TAAD as well as genotype-phenotype correlations that will allow for management to be targeted to not only the underlying gene harboring the pathogenic variant but also the specific mutation identified. The aortic dictionary, to which a clinician can turn to obtain information on clinical consequences of a specific genetic variants, is not only possible, but has been substantially written already. As additional entries to the dictionary are made, truly personalized, genetically based, aneurysm care can be delivered.

A mutation update on the LDS-associated genes TGFB2/3 and SMAD2/3

The Loeys–Dietz syndrome (LDS) is a connective tissue disorder affecting the cardiovascular, skeletal, and ocular system. Most typically, LDS patients present with aortic aneurysms and arterial tortuosity, hypertelorism, and bifid/broad uvula or cleft palate. Initially, mutations in transforming growth factor‐β (TGF‐β) receptors (TGFBR1 and TGFBR2) were described to cause LDS, hereby leading to impaired TGF‐β signaling. More recently, TGF‐β ligands, TGFB2 and TGFB3, as well as intracellular downstream effectors of the TGF‐β pathway, SMAD2 and SMAD3, were shown to be involved in LDS. This emphasizes the role of disturbed TGF‐β signaling in LDS pathogenesis. Since most literature so far has focused on TGFBR1/2, we provide a comprehensive review on the known and some novel TGFB2/3 and SMAD2/3 mutations. For TGFB2 and SMAD3, the clinical manifestations, both of the patients previously described in the literature and our newly reported patients, are summarized in detail. This clearly indicates that LDS concerns a disorder with a broad phenotypical spectrum that is still emerging as more patients will be identified. All mutations described here are present in the corresponding Leiden Open Variant Database.

TGF-β Signaling in Control of Cardiovascular Function

Genetic studies in animals and humans indicate that gene mutations that functionally perturb transforming growth factor β (TGF-β) signaling are linked to specific hereditary vascular syndromes, including Osler-Rendu-Weber disease or hereditary hemorrhagic telangiectasia and Marfan syndrome. Disturbed TGF-β signaling can also cause nonhereditary disorders like atherosclerosis and cardiac fibrosis. Accordingly, cell culture studies using endothelial cells or smooth muscle cells (SMCs), cultured alone or together in two- or three-dimensional cell culture assays, on plastic or embedded in matrix, have shown that TGF-β has a pivotal effect on endothelial and SMC proliferation, differentiation, migration, tube formation, and sprouting. Moreover, TGF-β can stimulate endothelial-to-mesenchymal transition, a process shown to be of key importance in heart valve cushion formation and in various pathological vascular processes. Here, we discuss the roles of TGF-β in vasculogenesis, angiogenesis, and lymphangiogenesis and the deregulation of TGF-β signaling in cardiovascular diseases.

Differences in manifestations of Marfan syndrome, Ehlers-Danlos syndrome, and Loeys-Dietz syndrome

Many different heritable connective tissue disorders (HCTD) have been described over the past decades. These syndromes often affect the connective tissue of various organ systems, including heart, blood vessels, skin, joints, bone, eyes, and lungs. The discovery of these HCTD was followed by the identification of mutations in a wide range of genes encoding structural proteins, modifying enzymes, or components of the TGFβ-signaling pathway. Three typical examples of HCTD are Marfan syndrome (MFS), Ehlers-Danlos syndrome (EDS), and Loeys-Dietz syndrome (LDS). These syndromes show some degree of phenotypical overlap of cardiovascular, skeletal, and cutaneous features. MFS is typically characterized by cardiovascular, ocular, and skeletal manifestations and is caused by heterozygous mutations in FBN1, coding for the extracellular matrix (ECM) protein fibrillin-1. The most common cardiovascular phenotype involves aortic aneurysm and dissection at the sinuses of Valsalva. LDS is caused by mutations in TGBR1/2, SMAD2/3, or TGFB2/3, all coding for components of the TGFβ-signaling pathway. LDS can be distinguished from MFS by the unique presence of hypertelorism, bifid uvula or cleft palate, and widespread aortic and arterial aneurysm and tortuosity. Compared to MFS, LDS cardiovascular manifestations tend to be more severe. In contrast, no association is reported between LDS and the presence of ectopia lentis, a key distinguishing feature of MFS. Overlapping features between MFS and LDS include scoliosis, pes planus, anterior chest deformity, spontaneous pneumothorax, and dural ectasia. EDS refers to a group of clinically and genetically heterogeneous connective tissue disorders and all subtypes are characterized by variable abnormalities of skin, ligaments and joints, blood vessels, and internal organs. Typical presenting features include joint hypermobility, skin hyperextensibility, and tissue fragility. Up to one quarter of the EDS patients show aortic aneurysmal disease. The latest EDS nosology distinguishes 13 subtypes. Many phenotypic features show overlap between the different subtypes, which makes the clinical diagnosis rather difficult and highlights the importance of molecular diagnostic confirmation.

Genes Associated with Thoracic Aortic Aneurysm and Dissection: An Update and Clinical Implications

Thoracic aortic aneurysm (TAA) is a lethal disease, with a natural history of enlarging progressively until dissection or rupture occurs. Since the discovery almost 20 years ago that ascending TAAs are highly familial, our understanding of the genetics of thoracic aortic aneurysm and dissection (TAAD) has increased exponentially. At least 29 genes have been shown to be associated with the development of TAAD, the majority of which encode proteins involved in the extracellular matrix, smooth muscle cell contraction or metabolism, or the transforming growth factor-β signaling pathway. Almost one-quarter of TAAD patients have a mutation in one of these genes. In this review, we provide a summary of TAAD-associated genes, associated clinical features of the vasculature, and implications for surgical treatment of TAAD. With the widespread use of next-generation sequencing and development of novel functional assays, the future of the genetics of TAAD is bright, as both novel TAAD genes and variants within the genes will continue to be identified.

A missense TGFB2 variant p.(Arg320Cys) causes a paradoxical and striking increase in aortic TGFB1/2 expression

Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder with a range of cardiovascular, skeletal, craniofacial and cutaneous manifestations. LDS type 4 is caused by mutations in TGFβ ligand 2 (TGFB2) and based on the family pedigrees described to date, appears to have a milder clinical phenotype, often presenting with isolated aortic disease. We sought to investigate its molecular basis in a new pedigree. We identified a missense variant p.(Arg320Cys) (NM_003238.3) in a highly evolutionary conserved region of TGFB2 in a new LDS type 4 pedigree with multiple cases of aortic aneurysms and dissections. There was striking upregulation of TGFB1 and TGFB2 expression on immunofluorescent staining, and western blotting of the aortic tissue from the index case confirming the functional importance of the variant. This case highlights the striking paradox of predicted loss-of-function mutations in TGFB2 causing enhanced TGFβ signaling in this emerging familial aortopathy.

Phenotypic variability and diffuse arterial lesions in a family with Loeys-Dietz syndrome type 4

Syndromic thoracic aortic aneurysm and dissection (TAAD) can suggest Marfan, vascular Ehlers-Danlos or Loeys-Dietz (LDS) syndromes. Several of the TGFβ-pathway-related genes predispose to different types of LDS. Heterozygous loss-of-function variations in TGFβ2 have been shown to be responsible for a novel form of syndromic TAAD associated with an impairment of the mitral valve and cerebrovascular disease called Loeys-Dietz syndrome type 4 (LDS4). We report the clinical characterization of a LDS4 French family with sudden deaths and diffuse vascular lesions, caused by a frameshift mutation in TGFβ2 gene: c.[995del]; p.(Leu332TrpfsTer27). Clinical characteristics include aneurysm of aortic sinus, skeletal and cutaneous features compatible with a syndromic form of TAAD (joint hypermobility, scoliosis, and easy bruises), intracranial aneurysms and rare mitral valve involvement. Iliac aneurysms, systemic medium caliber arteries dissections, and mild developmental delay were present in the family, and have not been described in LDS4. Phenotypic variability was also an important finding, including absence of clinical vascular events at advanced age in one case. Our data expand the phenotype of LDS4: we confirm that TGFβ2 mutations are responsible for true LDS syndrome with non-specific features of connective tissue disorders and diffuse vascular lesions. Adapted vascular follow up and prevention has to be proposed for these patients.

Clinically relevant variants identified in thoracic aortic aneurysm patients by research exome sequencing

Thoracic aortic aneurysm (TAA) is a genetically heterogeneous disease involving subclinical and progressive dilation of the thoracic aorta, which can lead to life-threatening complications such as dissection or rupture. Genetic testing is important for risk stratification and identification of at risk family members, and clinically available genetic testing panels have been expanding rapidly. However, when past testing results are normal, there is little evidence to guide decision-making about the indications and timing to pursue additional clinical genetic testing. Results from research based genetic testing can help inform this process. Here we present 10 TAA patients who have a family history of disease and who enrolled in research-based exome testing. Nine of these ten patients had previous clinical genetic testing that did not identify the cause of disease. We sought to determine the number of rare variants in 23 known TAA associated genes identified by research-based exome testing. In total, we found 10 rare variants in six patients. Likely pathogenic variants included a TGFB2 variant in one patient and a SMAD3 variant in another. These variants have been reported previously in individuals with similar phenotypes. Variants of uncertain significance of particular interest included novel variants in MYLK and MFAP5, which were identified in a third patient. In total, clinically reportable rare variants were found in 6/10 (60%) patients, with at least 2/10 (20%) patients having likely pathogenic variants identified. These data indicate that consideration of re-testing is important in TAA patients with previous negative or inconclusive results.

Fibulin-4 deficiency increases TGF-β signalling in aortic smooth muscle cells due to elevated TGF-β2 levels

Fibulins are extracellular matrix proteins associated with elastic fibres. Homozygous Fibulin-4 mutations lead to life-threatening abnormalities such as aortic aneurysms. Aortic aneurysms in Fibulin-4 mutant mice were associated with upregulation of TGF-β signalling. How Fibulin-4 deficiency leads to deregulation of the TGF-β pathway is largely unknown. Isolated aortic smooth muscle cells (SMCs) from Fibulin-4 deficient mice showed reduced growth, which could be reversed by treatment with TGF-β neutralizing antibodies. In Fibulin-4 deficient SMCs increased TGF-β signalling was detected using a transcriptional reporter assay and by increased SMAD2 phosphorylation. Next, we investigated if the increased activity was due to increased levels of the three TGF-β isoforms. These data revealed slightly increased TGF-β1 and markedly increased TGF-β2 levels. Significantly increased TGF-β2 levels were also detectable in plasma from homozygous Fibulin-4(R/R) mice, not in wild type mice. TGF-β2 levels were reduced after losartan treatment, an angiotensin-II type-1 receptor blocker, known to prevent aortic aneurysm formation. In conclusion, we have shown increased TGF-β signalling in isolated SMCs from Fibulin-4 deficient mouse aortas, not only caused by increased levels of TGF-β1, but especially TGF-β2. These data provide new insights in the molecular interaction between Fibulin-4 and TGF-β pathway regulation in the pathogenesis of aortic aneurysms.

The Expanding Clinical Spectrum of Extracardiovascular and Cardiovascular Manifestations of Heritable Thoracic Aortic Aneurysm and Dissection

More than 30 heritable conditions are associated with thoracic aortic aneurysm and dissection (TAAD). Heritable syndromic conditions, such as Marfan syndrome, Loeys-Dietz syndrome, and vascular Ehlers-Danlos syndrome, have somewhat overlapping systemic features, but careful clinical assessment usually enables a diagnosis that can be validated with genetic testing. Nonsyndromic FTAAD can also occur and in 20%-25% of these probands mutations exist in genes that encode elements of the extracellular matrix, signalling pathways (especially involving transforming growth factor-β), and vascular smooth muscle cytoskeletal and contractile processes. Affected individuals with either a syndromic presentation or isolated TAAD can have mutations in the same gene. In this review we focus on the genes currently known to have causal mutations for syndromic and isolated FTAAD and outline the range of associated extracardiovascular and cardiovascular manifestations with each.

Gene panel sequencing in heritable thoracic aortic disorders and related entities - results of comprehensive testing in a cohort of 264 patients

Background

Heritable Thoracic Aortic Disorders (H-TAD) may present clinically as part of a syndromic entity or as an isolated (nonsyndromic) manifestation. About one dozen genes are now available for clinical molecular testing. Targeted single gene testing is hampered by significant clinical overlap between syndromic H-TAD entities and the absence of discriminating features in isolated cases. Therefore panel testing of multiple genes has now emerged as the preferred approach. So far, no data on mutation detection rate with this technique have been reported.

Methods

We performed Next Generation Sequencing (NGS) based screening of the seven currently most prevalent H-TAD-associated genes (FBN1, TGFBR1/2, TGFB2, SMAD3, ACTA2 and COL3A1) on 264 samples from unrelated probands referred for H-TAD and related entities. Patients fulfilling the criteria for Marfan syndrome (MFS) were only included if targeted FBN1 sequencing and MLPA analysis were negative.

Results

A mutation was identified in 34 patients (13%): 12 FBN1, one TGFBR1, two TGFBR2, three TGFB2, nine SMAD3, four ACTA2 and three COL3A1 mutations. We found mutations in FBN1 (N = 3), TGFBR2 (N = 1) and COL3A1 (N = 2) in patients without characteristic clinical features of syndromal H-TAD. Six TAD patients harboring a mutation in SMAD3 and one TAD patient with a TGFB2 mutation fulfilled the diagnostic criteria for MFS.

Conclusion

NGS based H-TAD panel testing efficiently reveals a mutation in 13% of patients. Our observations emphasize the clinical overlap between patients harboring mutations in syndromic and nonsyndromic H-TAD related genes as well as within syndromic H-TAD entities, justifying a widespread application of this technique.

Electronic supplementary material

The online version of this article (doi:10.1186/s13023-014-0221-6) contains supplementary material, which is available to authorized users.

Further delineation of Loeys-Dietz syndrome type 4 in a family with mild vascular involvement and a TGFB2 splicing mutation

Background

The Loeys-Dietz syndrome (LDS) is a rare autosomal dominant disorder characterized by thoracic aortic aneurysm and dissection and widespread systemic connective tissue involvement. LDS type 1 to 4 are caused by mutations in genes of the TGF-β signaling pathway: TGFBR1 and TGFBR2 encoding the TGF-β receptor (LDS1 and LDS2), SMAD3 encoding the TGF-β receptor cytoplasmic effector (LDS3), and TGFB2 encoding the TGF-β2 ligand (LDS4). LDS4 represents the mildest end of the LDS spectrum, since aneurysms are usually observed in fourth decade and the progression of the disease is slower than in the other forms.

Case presentation

We report the clinical and molecular findings of an LDS4 Italian family. Genetic testing included TGFBR1, TGFBR2, SMAD3, and TGFB2 analysis by Sanger sequencing. In order to verify the effect of the identified splice mutation, RT-PCR analysis was performed.

The proband, a 57-year-old woman, showed high palate, hypoplasic uvula, easy bruising, joint hypermobility, chronic pain, scoliosis, multiple relapsing hernias, dural ectasia, and mitral valve prolapse. Magnetic resonance angiography revealed tortuosity and ectasia of carotid, vertebral, cerebral, and segmental pulmonary arteries. Arterial aneurysm and dissection never occurred. Her 39- and 34-year-old daughters presented with a variable degree of musculoskeletal involvement. Molecular analysis disclosed the novel c.839-1G>A splice site mutation in the TGFB2 gene. This mutation activates a cryptic splice acceptor site in exon 6 leading to frameshift, premature termination codon and haploinsufficiency (p.Gly280Aspfs*41).

Conclusions

Our data confirm that loss-of-function mutations in TGFB2 gene do not always lead to aggressive vascular phenotypes and that articular and skeletal signs are prevalent, therefore suggesting that LDS4 must be considered in patients with sparse signs of LDS and related disorders also in the absence of vascular events.

Whole exome sequencing for the identification of a new mutation in TGFB2 involved in a familial case of non-syndromic aortic disease

BACKGROUND

Non-syndromic aortic disease (NSAD) is a frequently asymptomatic but potentially lethal disease characterised by familial cases of thoracic aortic aneurysms and dissections. This monogenic but genetically heterogeneous condition is primarily inherited as an autosomal dominant disorder with low penetrance and variable expression. Mutations in ACTA2, TGFBR1, TGFBR2, MYH11, SMAD3, MYLK, and FBN1 genes have been described but still, there are many unresolved familial cases.

METHODS

The whole exome of two distantly related and affected members of a Spanish family with multiple cases of NSAD was analysed through 5500 SOLiD(™) System for the identification of shared and putative pathogenic variants.

RESULTS

A new mutation termed c.C1042T:p.R348C (NM_001135599.2) was identified in TGFB2, a gene located in an evolutionary highly conserved region (Chr1: 218,519,577-218,617,961) that has been recently connected to this disease. The analysis of other family members using capillary sequencing confirmed cosegregation of the mutation with the disease and its incomplete penetrance.

CONCLUSIONS

The repeated implication of TGFB2 in the development of thoracic aortic aneurysms and dissections suggests that this gene should be considered during genetic diagnosis of this disease. An accurate diagnosis of affected individuals and additional family members at risk allows for a personalised and more efficient gene-based follow-up and treatment. Finally, the reiterative presence of common musculoskeletal and craniofacial additional features in patients with TGFB2 mutations suggests the existence of a new yet undefined connective tissue syndrome responsible for not only aortic dilation, but also for the other extracardiac alterations present in the affected patients.

Generation of mice carrying a knockout-first and conditional-ready allele of transforming growth factor beta2 gene

Transforming growth factor beta2 (TGFβ2) is a multifunctional protein which is expressed in several embryonic and adult organs. TGFB2 mutations can cause Loeys Dietz syndrome, and its dysregulation is involved in cardiovascular, skeletal, ocular, and neuromuscular diseases, osteoarthritis, tissue fibrosis, and various forms of cancer. TGFβ2 is involved in cell growth, apoptosis, cell migration, cell differentiation, cell-matrix remodeling, epithelial-mesenchymal transition, and wound healing in a highly context-dependent and tissue-specific manner. Tgfb2(-/-) mice die perinatally from congenital heart disease, precluding functional studies in adults. Here, we have generated mice harboring Tgfb2(βgeo) (knockout-first lacZ-tagged insertion) gene-trap allele and Tgfb2(flox) conditional allele. Tgfb2(βgeo/βgeo) or Tgfb2(βgeo/-) mice died at perinatal stage from the same congenital heart defects as Tgfb2(-/-) mice. β-galactosidase staining successfully detected Tgfb2 expression in the heterozygous Tgfb2(βgeo) fetal tissue sections. Tgfb2(flox) mice were produced by crossing the Tgfb2(+/βgeo) mice with the FLPeR mice. Tgfb2(flox/-) mice were viable. Tgfb2 conditional knockout (Tgfb2(cko/-) ) fetuses were generated by crossing of Tgfb2(flox/-) mice with Tgfb2(+/-) ; EIIaCre mice. Systemic Tgfb2(cko/-) embryos developed cardiac defects which resembled the Tgfb2(βgeo/βgeo) , Tgfb2(βgeo/-) , and Tgfb2(-/-) fetuses. In conclusion, Tgfb2(βgeo) and Tgfb2(flox) mice are novel mouse strains which will be useful for investigating the tissue specific expression and function of TGFβ2 in embryonic development, adult organs, and disease pathogenesis and cancer. genesis

Loeys-Dietz syndrome: a primer for diagnosis and management

Loeys-Dietz syndrome is a connective tissue disorder predisposing individuals to aortic and arterial aneurysms. Presenting with a wide spectrum of multisystem involvement, medical management for some individuals is complex. This review of literature and expert opinion aims to provide medical guidelines for care of individuals with Loeys-Dietz syndrome.

Role of TGF-β pathway polymorphisms in sporadic thoracic aortic aneurysm: rs900 TGF-β2 is a marker of differential gender susceptibility

Thoracic aortic aneurysm (TAA) is a progressive disorder involving gradual dilation of ascending and/or descending thoracic aorta with dissection or rupture as complications. It occurs as sporadic or defined syndromes/familial forms.Genetic, molecular and cellular mechanims of sporadic TAA forms are poorly characterized and known. Thus, our interest has been focused on investigating the role of genetic variants of transforming growth factor-β (TGF-β) pathways in TAA risk. On the other hand, no data on the role of genetic variants of TGF-β pathway in sporadic TAA exist until now. In addition, other cytokines, including IL-10, orchestrate TAA pathophysiology. Their balance determines the ultimate fate of the aortic wall as healing atherosclerosis or aneurysm formation. Thus, in this paper it was analyzed the role of ten polymorphisms of genes encoding TGF-β isoforms and receptors, and IL-10 in sporadic TAA. Our study included cases affected by sporadic TAA and two control groups. The most relevant finding obtained allows us to propose that rs900 TGF-β2 SNP is associated with sporadic TAA in women. This might open new perspectives for the analysis of sporadic TAA susceptibility factors and prevention.

Genes in Thoracic Aortic Aneurysms and Dissections - Do they Matter?: Translation and Integration of Research and Modern Genetic Techniques into Daily Clinical Practice

Since the identification of the fibrillin-1 gene as the causal gene for Marfan syndrome, our knowledge of molecular genetics and the applicability of genetic testing in clinical practice have expanded dramatically. Several new syndromes related to thoracic aortic aneurysms and dissections (TAAD) have been described and the list of underlying genes in syndromal and nonsyndromal TAAD already includes more than 10 different genes and is rapidly expanding. Based on this knowledge, our insights into the underlying pathophysiology of TAAD have improved significantly, and new opportunities for targeted treatment have emerged. Clinicians involved in the care of TAAD patients require a basic knowledge of the disease entities and need to be informed on the applicability of genetic testing in their patients and families. Gene-tailored treatment and management is indeed no science fiction anymore and should now be considered as part of good clinical practice. We provide a systematic overview of genetic TAAD entities and practical recommendations for genetic testing and patient management.