[Research progress of genetic research on Char syndrome].

Char syndrome is a rare autosomal dominant genetic disorder characterized by patent ductus arteriosus, facial dysmorphism, and dysplasia of fingers/toes. It may also be associated with multiple papillae, dental dysplasia, and sleep disorders. TFAP2B has proven to be a pathogenic gene for neural crest derivation and development, and several variants of this gene have been identified. Bone morphogenetic protein signaling plays an important role in embryonic development by participating in limb growth and patterning, and regulation of neural crest cell development. TFAP2B is an upstream regulatory gene for bone morphogenetic proteins 2 and 4. Variants of the TFAP2B gene may lead to abnormal proliferation of neural crest cells by affecting the expression of bone morphogenetic proteins, resulting in multiple organ dysplasia syndrome. In addition, TFAP2B variants may only lead to patent ductus arteriosus instead of typical Char syndrome.

A +3 variant at a donor splice site leads to a skipping of the MYH11 exon 32, a recurrent RNA defect causing Heritable Thoracic Aortic Aneurysm and Dissection and/or Patent Ductus Arteriosus.

BACKGROUND: Pathogenic variants in MYH11 are associated with either heritable thoracic aortic aneurysm and dissection (HTAAD), patent ductus arteriosus (PDA) syndrome, or megacystis-microcolon-intestinal hypoperistalsis syndrome (MMIHS). METHODS AND RESULTS: We report a family referred for molecular diagnosis with HTAAD/PDA phenotype in which we found a variant at a non-conserved position of the 5' donor splice site of intron 32 of MYH11 potentially altering splicing (NM_002474.3:c.4578+3A>C). Although its cosegregation with disease was observed, it remained of unknown significance. Later, aortic surgery in the proband gave us the opportunity to perform a transcript analysis. This showed a skipping of the exon 32, an RNA defect previously reported to be translated to an in-frame loss of 71 amino acids and a dominant-negative effect in the smooth muscle myosin rod. This RNA defect is also reported in 3 other HTAAD/PDA pedigrees. CONCLUSION: This report confirms that among rare variants in MYH11, skipping of exon 32 is recurrent. This finding is of particular interest to establish complex genotype-phenotype correlations where some alleles are associated with autosomal dominant HTAAD/PDA, while others result in recessive or dominant visceral myopathies.

Transcription factor AP-2beta in development, differentiation and tumorigenesis.

To date, the AP-2 family of transcription factors comprises five members. Transcription factor AP-2beta (TFAP2B)/AP-2ß was first described in 1995. Several studies indicate a critical role of AP-2ß in the development of tissues and organs of ectodermal, neuroectodermal and also mesodermal origin. Germline mutation of TFAP2B is known to cause the Char syndrome, an autosomal dominant disorder characterized by facial dysmorphism, patent ductus arteriosus and anatomical abnormalities of the fifth digit. Furthermore, single-nucleotide polymorphisms in TFAP2B were linked to obesity and specific personality traits. In neoplasias, AP-2ß was first described in alveolar rhabdomyosarcoma. Immunohistochemical staining of AP-2ß is a recommended ancillary test for the histopathological diagnosis of this uncommon childhood malignancy. In neuroblastoma, AP-2ß supports noradrenergic differentiation. Recently, the function of AP-2ß in breast cancer (BC) has gained interest. AP-2ß is associated with the lobular BC subtype. Moreover, AP-2ß controls BC cell proliferation and has a prognostic impact in patients with BC. This review provides a comprehensive overview of the current knowledge about AP-2ß and its function in organ development, differentiation and tumorigenesis.

Aneurysmal Dilatation of Ductus Arteriosus and Pulmonary Artery in Association With ACTA2 Mutation.

Actin α2 (ACTA2) is a protein crucial for proper functioning of contractile apparatus in smooth muscles. A specific mutation resulting in substitution of arginine at position 179 by histidine (p.R179 H) in ACTA2 has been shown to be associated with multisystemic smooth muscle dysfunction syndrome. Characteristic features include aneurysmal arterial disease. Due to rarity of this disease, we report a nine-year-old girl with this rare genetic variant in whom cardiovascular manifestations were identified in fetal life and who needed neonatal cardiac surgical intervention.

Vascular endothelial growth factor polymorphism rs2010963 status does not affect patent ductus arteriosus incidence or cyclooxygenase inhibitor treatment success in preterm infants.

BACKGROUND: Vascular endothelial growth factor is critically involved in ductus arteriosus closure. Polymorphisms in the vascular endothelial growth factor gene have been associated with several diseases in neonates and adults. AIM: Herein, we investigated if vascular endothelial growth factor polymorphism rs2010963 status is associated with patent ductus arteriosus incidence and/or pharmacological treatment success. METHODS: We assessed rs2010963 status in 814 preterm infants (<1500 g birth weight) by means of restriction fragment length polymorphism analysis. DNA samples were obtained from dry-spot cards used for the German national newborn screening program. Clinical data were obtained by retrospective chart review. RESULTS: We could not find any statistically significant difference in the incidence of patent ductus arteriosus depending on vascular endothelial growth factor rs2010963 polymorphism status. Furthermore, no statistically significant associations between vascular endothelial growth factor polymorphism rs2010963 status and cyclooxygenase inhibitor treatment success were observed. CONCLUSION: Our results indicate that there is no association between vascular endothelial growth factor polymorphism rs2010963 status and the occurrence of patent ductus arteriosus or the response to cyclooxygenase inhibitor treatment in a large cohort of preterm infants. Additional studies are needed to determine the role of genetic factors on patent ductus arteriosus incidence and treatment response.

Hypoxia-induced ARHGAP26 deficiency inhibits the proliferation and migration of human ductus arteriosus smooth muscle cell through activating RhoA-ROCK-PTEN pathway.

The Rho family plays crucial roles in O2 -induced vasoconstriction, cell proliferation, and migration. Rho GTPase-activating protein 26 (ARHGAP26) is a GTPase-activating protein for the small GTPases of the Rho family. Our previous studies have demonstrated that ARHGAP26 expression was significantly downregulated in patent human ductus arteriosus (DA) tissue. However, its role underlying the maintenance of DA patency is unclear. In this study, patent (fetal) and constricted (newborn) mouse DA tissues were harvested to confirm the differences in the levels of expression of ARHGAP26. Human DA smooth muscle cells (DASMCs) were isolated and cultured in vitro and used to test the function of ARHGAP26. The expression of ARHGAP26 was significantly lower in patent (fetal) than constricted (newborn) mouse DA. ARHGAP26-knocked-down human DASMCs showed reduced proliferation and migration, which are both crucial to anatomic closure of DA. Moreover, after culturing under hypoxic conditions, the expression of ARHGAP26 in human DASMCs was significantly lower and hypoxia-induced ARHGAP26 deficiency activated the phosphorylation level of phosphatase and tensin homolog (PTEN) in DASMCs by mediating the activity of RhoA and RhoA-associated kinase 1 (ROCK1). Use of Y27632, an inhibitor of ROCK which further reduces the phospholipid activity of PTEN can reverse the inhibitory effect of PTEN on the proliferation and migration of human DASMCs. This provides insight into the molecular regulation of the RhoA-ROCK-PTEN pathway in DA smooth muscle cells, which may be a suitable therapeutic target or diagnostic biomarker for perinatal DA tone management.

De Novo Mutations in SLC25A24 Cause a Craniosynostosis Syndrome with Hypertrichosis, Progeroid Appearance, and Mitochondrial Dysfunction.

Gorlin-Chaudhry-Moss syndrome (GCMS) is a dysmorphic syndrome characterized by coronal craniosynostosis and severe midface hypoplasia, body and facial hypertrichosis, microphthalmia, short stature, and short distal phalanges. Variable lipoatrophy and cutis laxa are the basis for a progeroid appearance. Using exome and genome sequencing, we identified the recurrent de novo mutations c.650G>A (p.Arg217His) and c.649C>T (p.Arg217Cys) in SLC25A24 in five unrelated girls diagnosed with GCMS. Two of the girls had pronounced neonatal progeroid features and were initially diagnosed with Wiedemann-Rautenstrauch syndrome. SLC25A24 encodes a mitochondrial inner membrane ATP-Mg/Pi carrier. In fibroblasts from affected individuals, the mutated SLC25A24 showed normal stability. In contrast to control cells, the probands' cells showed mitochondrial swelling, which was exacerbated upon treatment with hydrogen peroxide (H2O2). The same effect was observed after overexpression of the mutant cDNA. Under normal culture conditions, the mitochondrial membrane potential of the probands' fibroblasts was intact, whereas ATP content in the mitochondrial matrix was lower than that in control cells. However, upon H2O2 exposure, the membrane potential was significantly elevated in cells harboring the mutated SLC25A24. No reduction of mitochondrial DNA copy number was observed. These findings demonstrate that mitochondrial dysfunction with increased sensitivity to oxidative stress is due to the SLC25A24 mutations. Our results suggest that the SLC25A24 mutations induce a gain of pathological function and link mitochondrial ATP-Mg/Pi transport to the development of skeletal and connective tissue.

Functional Analyses of a Novel CITED2 Nonsynonymous Mutation in Chinese Tibetan Patients with Congenital Heart Disease.

CITED2 gene is an important cardiac transcription factor that plays a fundamental role in the formation and development of embryonic cardiovascular. Previous studies have showed that knock-out of CITED2 in mice might result in various cardiac malformations. However, the mechanisms of CITED2 mutation on congenital heart disease (CHD) in Chinese Tibetan population are still poorly understood. In the present study, 187 unrelated Tibetan patients with CHD and 200 unrelated Tibetan healthy controls were screened for variants in the CITED2 gene; we subsequently identified one potential disease-causing mutation p.G143A in a 6-year-old girl with PDA and functional analyses of the mutation were carried out. Our study showed that the novel mutation of CITED2 significantly enhanced the expression activity of vascular endothelial growth factor (VEGF) under the role of co-receptor hypoxia inducible factor 1-aipha (HIF-1A), which is closely related with embryonic cardiac development. As a result, CITED2 gene mutation may play a significant role in the development of pediatric congenital heart disease.

Two patients with the heterozygous R189H mutation in ACTA2 and Complex congenital heart defects expands the cardiac phenotype of multisystemic smooth muscle dysfunction syndrome.

De novo heterozygous mutations changing R179 to histidine, leucine, or cysteine in the ACTA2 gene are associated with Multisystemic Smooth Muscle Dysfunction Syndrome (MSMDS). Characteristic hallmarks of this condition, caused only by these specific ACTA2 mutations, are congenital mydriasis (mid-dilated, non-reactive pupils), a large persistent ductus arteriosus (PDA), aortic aneurysms evolving during childhood, and cerebrovascular anomalies. We describe two patients, a 3-day-old newborn and a 26-year-old woman, with this unique mutation in association with a huge PDA and an aorto-pulmonary window. In addition, one showed a coarctation of the aortic arch and the other a complete interruption of the aortic arch type A; thereby expanding the spectrum of cardiac congenital heart defect of this syndrome. Each patient displayed a huge PDA and an extra-cardiovascular phenotype consistent with MSMDS. These observations exemplify that a functional alpha 2 smooth muscle actin is necessary for proper cardiovascular organ development, and demonstrate that a very exceptional congenital heart defect (aortopulmonary window) can be caused by a mutation in a gene encoding a contractile protein of vascular smooth muscle cells. © 2017 Wiley Periodicals, Inc.

Utilization of Whole Exome Sequencing to Identify Causative Mutations in Familial Congenital Heart Disease.

BACKGROUND: Congenital heart disease (CHD) is the most common type of birth defect with family- and population-based studies supporting a strong genetic cause for CHD. The goal of this study was to determine whether a whole exome sequencing (WES) approach could identify pathogenic-segregating variants in multiplex CHD families. METHODS AND RESULTS: WES was performed on 9 kindreds with familial CHD, 4 with atrial septal defects, 2 with patent ductus arteriosus, 2 with tetralogy of Fallot, and 1 with pulmonary valve dysplasia. Rare variants (<1% minor allele frequency) that segregated with disease were identified by WES, and variants in 69 CHD candidate genes were further analyzed. These selected variants were subjected to in silico analysis to predict pathogenicity and resulted in the discovery of likely pathogenic mutations in 3 of 9 (33%) families. A GATA4 mutation in the transactivation domain, p.G115W, was identified in familial atrial septal defects and demonstrated decreased transactivation ability in vitro. A p.I263V mutation in TLL1 was identified in an atrial septal defects kindred and is predicted to affect the enzymatic functionality of TLL1. A disease-segregating splice donor site mutation in MYH11 (c.4599+1delG) was identified in familial patent ductus arteriosus and found to disrupt normal splicing of MYH11 mRNA in the affected individual. CONCLUSIONS: Our findings demonstrate the clinical utility of WES to identify causative mutations in familial CHD and demonstrate the successful use of a CHD candidate gene list to allow for a more streamlined approach enabling rapid prioritization and identification of likely pathogenic variants from large WES data sets. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov; Unique Identifier: NCT0112048.

Microarray gene expression analysis in ovine ductus arteriosus during fetal development and birth transition.

BACKGROUND: Patent ductus arteriosus (PDA) in the newborn is the most common congenital heart anomaly and is significantly more common in preterm infants. Contemporary pharmacological treatment is effective in only 70-80% of the cases. Moreover, indomethacin or ibuprofen, which are used to close a PDA may be accompanied by serious side effects in premature infants. To explore the novel molecular pathways, which may be involved in the maturation and closure of the ductus arteriosus (DA), we used fetal and neonatal sheep to test the hypothesis that maturational development of DA is associated with significant alterations in specific mRNA expression. METHODS: We conducted oligonucleotide microarray experiments on the isolated mRNA from DA and ascending aorta from three study groups (premature fetus-97 ± 0 d, near-term fetus-136 ± 0.8 d, and newborn lamb-12 ± 0 h). We compared the alterations in mRNA expression in DA and aorta to identify genes specifically involved in DA maturation. RESULTS: Results demonstrate significant changes in wingless-integrin1, thrombospondin 1, receptor activator of nuclear factor-kappa B, nitric oxide synthase, and retinoic acid receptor activation signaling pathways. CONCLUSION: We conclude that these pathways may play an important role during both development and postnatal DA closure and warrant further investigation.

An analysis of cardiac defects and surgical interventions in 84 cases with full trisomy 18.

Trisomy 18 (Edwards syndrome) is the second most common autosomal trisomy after trisomy 21. Medical issues commonly include cardiac defects, such as ventricular septal defect (VSD) and atrial septal defect (ASD). If untreated, these conditions can contribute to the associated infant mortality. The objective of the study was review parent-reported information on 84 cases with full trisomy 18 focusing on prenatal and postnatal assessment and confirmation of cardiac defects and on subsequent treatment with cardiac surgery and post-surgery outcomes. At birth, 65 parent responses indicated the presence of VSD (77.4%), 38 ASD (45.2%), and 50 patent ductus arteriosus (PDA) (59.5%). The presence of multiple cardiac defects was also analyzed including 25 cases with VSD, ASD, and PDA at birth. The total reduced to 18 at survey completion. Twenty-four cases had one or more cardiac defects repaired for a total of 34 corrective surgeries. Age at surgery varied from 2 weeks to 41 months of age with most performed under 1 year of age. Twenty-one cases were still living at the time of survey completion (87.5%). From these date we provide recommendations and implications.

Single nucleotide polymorphisms in AGTR1, TFAP2B, and TRAF1 are not associated with the incidence of patent ductus arteriosus in Japanese preterm infants.

BACKGROUND: Persistent patent ductus arteriosus (PDA) is a frequent complication in preterm infants. Single nucleotide polymorphisms (SNP) in several genes, including angiotensin II receptor, type 1 (AGTR1), transcription factor AP-2 beta (TFAP2B) and tumor necrosis factor receptor-associated factor 1 (TRAF1), have been reported to be associated with PDA in preterm infants. The aim of this study was to evaluate the relationships between PDA in preterm infants and polymorphisms in AGTR1, TFAP2B and TRAF1 in the Japanese population. METHODS: The subjects consisted of 107 preterm infants with gestational age <32 weeks. Extremely low-birthweight infants were treated with prophylactic indomethacin during the first 24 h after birth. Five SNP, namely, rs5186 in AGTR1, rs987237 and rs6930924 in TFAP2B, and rs1056567 and rs10985070 in TRAF1, were genotyped using TaqMan SNP genotyping assays. RESULTS: There were no significant differences in the distributions of the genotypes and allele frequencies of all studied SNP between the PDA group (n = 46) and the non-PDA group (n = 61). CONCLUSIONS: There were no significant associations between the studied SNP and the incidence of PDA in Japanese preterm infants. These SNP may not be clinically important predisposing factors for PDA in Japanese preterm infants.

Effects of Advancing Gestation and Non-Caucasian Race on Ductus Arteriosus Gene Expression.

OBJECTIVE: To identify genes affected by advancing gestation and racial/ethnic origin in human ductus arteriosus (DA). STUDY DESIGN: We collected 3 sets of DA tissue (n = 93, n = 89, n = 91; total = 273 fetuses) from second trimester pregnancies. We examined four genes, with DNA polymorphisms that distribute along racial lines, to identify "Caucasian" and "non-Caucasian" DA. We used real time polymerase chain reaction to measure RNA expression of 48 candidate genes involved in functional closure of the DA, and used multivariable regression analyses to examine the relationships between advancing gestation, "non-Caucasian" race, and gene expression. RESULTS: Mature gestation and non-Caucasian race are significant predictors for identifying infants who will close their patent DA when treated with indomethacin. Advancing gestation consistently altered gene expression in pathways involved with oxygen-induced constriction (eg, calcium-channels, potassium-channels, and endothelin signaling), contractile protein maturation, tissue remodeling, and prostaglandin and nitric oxide signaling in all 3 tissue sets. None of the pathways involved with oxygen-induced constriction appeared to be altered in "non-Caucasian" DA. Two genes, SLCO2A1 and NOS3, (involved with prostaglandin reuptake/metabolism and nitric oxide production, respectively) were consistently decreased in "non-Caucasian" DA. CONCLUSIONS: Prostaglandins and nitric oxide are the most important vasodilators opposing DA closure. Indomethacin inhibits prostaglandin production, but not nitric oxide production. Because decreased SLCO2A1 and NOS3 expression can lead to increased prostaglandin and decreased nitric oxide concentrations, we speculate that prostaglandin-mediated vasodilation may play a more dominant role in maintaining the "non-Caucasian" patent DA, making it more likely to close when inhibited by indomethacin.

Potential Molecular Mechanism of Retrograde Aortic Arch Stenosis in the Hybrid Approach to Hypoplastic Left Heart Syndrome.

BACKGROUND: The hybrid palliation for hypoplastic left heart syndrome has emerged as an alternative approach to the Norwood procedure. The development of patent ductus arteriosus (PDA) in-stent stenosis can cause retrograde aortic arch stenosis (RAAS), leading to significant morbidity. This study aimed to identify potential mechanisms of PDA in-stent stenosis contributing to RAAS. METHODS: Tissues from stented PDAs were collected from 17 patients undergoing comprehensive stage II repair between 2009 and 2014. Patients requiring RAAS intervention based on cardiology-surgery consensus were defined as RAAS(+) (n = 10), whereas patients without any RAAS intervention were defined as RAAS(-) (n = 7). Tissues were examined by quantitative polymerase chain reaction analysis for vascular smooth muscle cell (VSMC) differentiation and proliferation markers. RESULTS: Patient characteristics were hypoplastic left heart syndrome with aortic atresia in 6 and with aortic stenosis in 3; unbalanced atrioventricular canal in 3; double-inlet left ventricle/transposition of the great arteries in 3; and double-outlet right ventricle in 2. VSMC differentiation markers (ß-actin, SM22, and calponin) and signaling pathways for VSMC modulation (transforming growth factor-ß1, Notch, and platelet derived growth factor-BB) were significantly higher in the RAAS(+) than in RAAS(-) patients. The proliferation marker Ki67 was increased in RAAS(+) patients. Cell cycle markers were comparable in both groups. CONCLUSIONS: Increased VSMC differentiation and proliferation markers suggest a mechanism for inward neointima formation of the PDA in RAAS. The apparent lack of change in cell cycle markers is contrary to coronary artery in-stent stenosis, suggesting further targets should be examined. Combined primary in vitro PDA cell culture and proteomics can be strong tools to elucidate targets to reduce PDA in-stent stenosis for RAAS in the future.

Isobaric Tags for Relative and Absolute Quantitation-Based Proteomic Analysis of Patent and Constricted Ductus Arteriosus Tissues Confirms the Systemic Regulation of Ductus Arteriosus Closure.

We aimed to evaluate global changes in protein expression associated with patency by undertaking proteomic analysis of human constricted and patent ductus arteriosus (DA). Ten constricted and 10 patent human DAs were excised from infants with ductal-dependent heart disease during surgery. Using isobaric tags for relative and absolute quantitation-based quantitative proteomics, 132 differentially expressed proteins were identified. Of 132 proteins, voltage-gated sodium channel 1.3 (SCN3A), myosin 1d (Myo1d), Rho GTPase activating protein 26 (ARHGAP26), and retinitis pigmentosa 1 (RP1) were selected for validation by Western blot and quantitative real-time polymerase chain reaction analyses. Significant upregulation of SCN3A, Myo1d, and RP1 messenger RNA, and protein levels was observed in the patent DA group (all P ≤ 0.048). ARHGAP26 messenger RNA and protein levels were decreased in patent DA tissue (both P ≤ 0.018). Immunohistochemistry analysis revealed that Myo1d, ARHGAP26, and RP1 were specifically expressed in the subendothelial region of constricted DAs; however, diffuse expression of these proteins was noted in the patent group. Proteomic analysis revealed global changes in the expression of proteins that regulate oxygen sensing, ion channels, smooth muscle cell migration, nervous system, immune system, and metabolism, suggesting a basis for the systemic regulation of DA patency by diverse signaling pathways, which will be confirmed in further studies.

MATR3 disruption in human and mouse associated with bicuspid aortic valve, aortic coarctation and patent ductus arteriosus.

Cardiac left ventricular outflow tract (LVOT) defects represent a common but heterogeneous subset of congenital heart disease for which gene identification has been difficult. We describe a 46,XY,t(1;5)(p36.11;q31.2)dn translocation carrier with pervasive developmental delay who also exhibited LVOT defects, including bicuspid aortic valve (BAV), coarctation of the aorta (CoA) and patent ductus arteriosus (PDA). The 1p breakpoint disrupts the 5' UTR of AHDC1, which encodes AT-hook DNA-binding motif containing-1 protein, and AHDC1-truncating mutations have recently been described in a syndrome that includes developmental delay, but not congenital heart disease [Xia, F., Bainbridge, M.N., Tan, T.Y., Wangler, M.F., Scheuerle, A.E., Zackai, E.H., Harr, M.H., Sutton, V.R., Nalam, R.L., Zhu, W. et al. (2014) De Novo truncating mutations in AHDC1 in individuals with syndromic expressive language delay, hypotonia, and sleep apnea. Am. J. Hum. Genet., 94, 784-789]. On the other hand, the 5q translocation breakpoint disrupts the 3' UTR of MATR3, which encodes the nuclear matrix protein Matrin 3, and mouse Matr3 is strongly expressed in neural crest, developing heart and great vessels, whereas Ahdc1 is not. To further establish MATR3 3' UTR disruption as the cause of the proband's LVOT defects, we prepared a mouse Matr3(Gt-ex13) gene trap allele that disrupted the 3' portion of the gene. Matr3(Gt-ex13) homozygotes are early embryo lethal, but Matr3(Gt-ex13) heterozygotes exhibit incompletely penetrant BAV, CoA and PDA phenotypes similar to those in the human proband, as well as ventricular septal defect (VSD) and double-outlet right ventricle (DORV). Both the human MATR3 translocation breakpoint and the mouse Matr3(Gt-ex13) gene trap insertion disturb the polyadenylation of MATR3 transcripts and alter Matrin 3 protein expression, quantitatively or qualitatively. Thus, subtle perturbations in Matrin 3 expression appear to cause similar LVOT defects in human and mouse.

Elevated NCX1 and NCKX4 expression in the patent postnatal ductus arteriosus of ductal-dependent congenital heart disease patients.

Patency of the ductus arteriosus (DA) after birth is essential in ductal-dependent congenital heart disease. The Na(+)/Ca(2+) exchanger (NCX) has been demonstrated to play a key role in regulating vascular tone. The potassium-dependent Na(+)/Ca(2+) exchanger (NCKX) is a related family of NCX depending on the K(+) gradients which triggers DA constriction. The present study investigated the comparative expression of NCX and NCKX between a constricted DA and patent DA in human ductal-dependant congenital heart disease. Human DAs, which were patent (n = 10, age = 20.2 ± 4.3 days) or constricted (n = 10, age = 18.3 ± 3.9 days), were excised during surgery from neonates with ductal-dependent congenital heart disease. Western blotting analysis, real-time quantitative polymerase chain reaction analysis and immunofluorescence studies were performed to detect the protein and mRNA levels of NCX1, NCKX3, and NCKX4. The expressions of NCX1 and NCKX4 were significantly higher in the patent DA group at both the protein and mRNA levels, and expression was localized to the smooth muscle layer. These findings indicate that NCX1 and NCKX4 are up-regulated in human postnatal patent DAs and may represent potential therapeutic targets for maintaining DA patency in ductal-dependent congenital heart disease.

Transcriptional profiling reveals ductus arteriosus-specific genes that regulate vascular tone.

Failure of the ductus arteriosus (DA) to close at birth can lead to serious complications. Conversely, certain profound congenital cardiac malformations require the DA to be patent until corrective surgery can be performed. In each instance, clinicians have a very limited repertoire of therapeutic options at their disposal - indomethacin or ibuprofen to close a patent DA (PDA) and prostaglandin E1 to maintain patency of the DA. Neither treatment is specific to the DA and both may have deleterious off-target effects. Therefore, more therapeutic options specifically targeted to the DA should be considered. We hypothesized the DA possesses a unique genetic signature that would set it apart from other vessels. A microarray was used to compare the genetic profiles of the murine DA and ascending aorta (AO). Over 4,000 genes were differentially expressed between these vessels including a subset of ion channel-related genes. Specifically, the alpha and beta subunits of large-conductance calcium-activated potassium (BKCa) channels are enriched in the DA. Gain- and loss-of-function studies showed inhibition of BKCa channels caused the DA to constrict, while activation caused DA relaxation even in the presence of O2. This study identifies subsets of genes that are enriched in the DA that may be used to develop DA-specific drugs. Ion channels that regulate DA tone, including BKCa channels, are promising targets. Specifically, BKCa channel agonists like NS1619 maintain DA patency even in the presence of O2 and may be clinically useful.