Single nucleotide polymorphisms in the dual specificity phosphatase genes and risk of necrotizing enterocolitis in premature infant.

BACKGROUND: Differences in the susceptibility of preterm infants to develop necrotizing enterocolitis (NEC) implicate potential genetic differences in response to the inflammatory stimuli leading to NEC. Dual specificity phosphatases (DUSPs) are a key suppressor pathway of the mitogen-activated protein kinase (MAPK) pro-inflammatory signaling pathway. We hypothesized that inherited single nucleotide polymorphisms (SNPs) in DUSP genes contribute to NEC susceptibility in premature infants. METHODS: Patients admitted between 2010 and 2015 born at <  32 weeks GA and≤1,500 g BW with stage II+NEC (cases; n = 50) and age, weight-matched controls (n = 38) were included. Blood samples were collected for DNA isolation. Agena Mass Array assay was used to examine 31 SNPs in 9 different DUSP genes. Calculated minor allele frequencies (MAF) for cases and controls were compared using χ2 and logistic regression. RESULTS: The presence of the rs704074 SNP was associated with a 48% decreased risk of developing NEC (OR 0.52; 95% CI 0.27- 1.01, p = 0.04). The odds of surgical NEC decreased by 78% (OR 0.22; 95% CI 0.06- 0.84, p = 0.027) for each copy of rs704074/G allele in patients with NEC. CONCLUSION: In this small single-center pilot study, DUSP-6 SNP (rs704074) was associated with a lower risk of developing NEC and surgical NEC, the most severe form of NEC, in preterm infants.

Using clinical and genetic data to predict pulmonary hypertension in bronchopulmonary dysplasia.

AIM: Pulmonary hypertension significantly increases morbidity and mortality in infants with bronchopulmonary dysplasia. The frequency of single nucleotide polymorphisms in arginase-1 (ARG1 rs2781666) and dimethylarginine dimethylaminohydrolase-1 (DDAH1 rs480414) genes has been found to differ in a cohort of bronchopulmonary dysplasia patients with pulmonary hypertension (cases) and without pulmonary hypertension (controls). Therefore, we tested the hypothesis that combining these genotypes with phenotypic data would better predict pulmonary hypertension in bronchopulmonary dysplasia patients. METHODS: Bronchopulmonary dysplasia patients (n = 79) born at <35 weeks gestation were studied. Pulmonary hypertension was diagnosed by echocardiographic criteria (n = 20). ROC curves to predict pulmonary hypertension in bronchopulmonary dysplasia were generated from genotype and/or clinical data. RESULTS: Cases were born at an earlier gestation and weighed less at birth than did controls. ROC curves for rs2781666 had an AUC of 0.61, while rs480414 had an AUC of 0.66. Together, the AUC was 0.70. When clinical data were added to the genetic model, AUC was 0.73. CONCLUSION: These findings demonstrate that ROC predictive modelling of pulmonary hypertension in bronchopulmonary dysplasia improves with inclusion of both genotypic and phenotypic data. Further refinement of these types of models could facilitate the implementation of precision medicine approaches to pulmonary hypertension in bronchopulmonary dysplasia.

Arginase I gene single-nucleotide polymorphism is associated with decreased risk of pulmonary hypertension in bronchopulmonary dysplasia.

AIM: To test the hypothesis that there are single-nucleotide polymorphisms (SNPs) in genes of the l-arginine/nitric oxide pathway associated with pulmonary hypertension (PH) in neonates with bronchopulmonary dysplasia (BPD). METHODS: Neonates with BPD were enrolled (n = 140) and clinical characteristics compared between case (BPD + PH) and control (BPD) groups. DNA was isolated from blood leucocytes and assayed for 17 SNPs in l-arginine/nitric oxide pathway genes by Sequenom massarray. Genes included carbamoyl-phosphate synthetase, ornithine transcarbamylase, argininosuccinate synthase, nitric oxide synthase and arginase. SNPs were selected from the National Center for Biotechnology Information database for their putative functionality. Calculated minor allele frequencies (MAF) of cases and controls were compared using χ2 and logistic regression. RESULTS: Of the 140 patients with BPD, 26% had echocardiographic evidence of PH. Ventilation days were longer for cases than controls (mean 31 vs. 15 days, p < 0.05). Of the 17 SNPs, rs2781666 in arginase I gene was less common in cases (MAF = 0.23) than controls (MAF = 0.37, p = 0.04). The odds of PH decreased by 43% (p = 0.047) for each copy of the SNP minor allele in arginase I gene in patients with BPD. CONCLUSION: Arginase I SNP (rs2781666) may be associated with protection against pulmonary hypertension in preterm neonates with BPD.

Deficiency of Atf3, an adaptive-response gene, protects islets and ameliorates inflammation in a syngeneic mouse transplantation model.

AIMS/HYPOTHESIS: Islet transplantation is a potential therapeutic option for type 1 diabetes. However, the need for multiple donors per patient and heavy immunosuppression of the recipients limit its use. The goal of this study was to test whether the gene encoding activating transcription factor 3 (ATF3), a stress-inducible pro-apoptotic gene, plays a role in graft rejection in islet transplantation. METHODS: We compared wild-type (WT) and Atf3 knockout (KO) islets in vitro using stress paradigms relevant to islet transplantation: isolation, inflammation and hypoxia. We also compared the WT and KO islets in vivo using a syngeneic mouse transplantation model. RESULTS: ATF3 was induced in all three stress paradigms and played a deleterious role in islet survival, as evidenced by the lower viability of WT islets compared with KO islets. ATF3 upregulated various downstream target genes in a stress-dependent manner. These target genes can be classified into two functional groups: (1) apoptosis (Noxa [also known as Pmaip1] and Bnip3), and (2) immunomodulation (Tnfalpha [also known as Tnf], Il-1beta [also known as Il1b], Il-6 [also known as Il6] and Ccl2 [also known as Mcp-1]). In vivo, Atf3 KO islets performed better than WT islets after transplantation, as evidenced by better glucose homeostasis in the recipients and the reduction of the following variables in the KO grafts: caspase 3 activation, macrophage infiltration and expression of the above apoptotic and immunomodulatory genes. CONCLUSIONS/INTERPRETATION: ATF3 plays a role in islet graft rejection by contributing to islet cell death and inflammatory responses at the graft sites. Silencing the ATF3 gene may provide therapeutic benefits in islet transplantation.