Identification and characterization of the VAX2 p.Leu139Arg variant: possible involvement of VAX2 in cone dystrophy

Objective: This study was undertaken with the objective to investigate the potential involvement of VAX2 in retinal degeneration.

Methods: A cohort of macular and cone dystrophy patients (n = 70) was screened for variant identification. Polymerase chain reaction (PCR) products were purified using ExoSAP-IT. Direct sequencing of PCR products was performed using BigDye 3.1 on the ABI 3730 DNA Analyzer and analyzed using DNASTAR software tool. Search for known variant was performed using the following platforms: 1000 Genomes Project, Ensembl, UCSC, ExAc, and dbSNP. The VAX2 mutants were generated using the GeneArt® Site-Directed Mutagenesis kit. In vitro analysis was performed in hTERTRPE-1 (RPE-1) cell line. Cells were photographed using a Zeiss AXIOVERT S100 microscope. Images were analyzed using Photoshop CS4 software.

Results: Here, we report the identification of a heterozygous non-synonymous variant (c.416T>G; p.Leu139Arg) in one cone dystrophy proband. Functional characterization of this variant in vitro revealed an aberrant phenotype seen as protein mislocalization to cytoplasm/nucleus and aggregates undergoing degradation or forming aggresomes. The cellular phenotype suggests protein loss-of-function. Analysis of the VAX2 p.Leu139Met, a variant present in the normal population, showed a phenotype similar to the wild-type, further supporting the hypothesis for the Leucine 139 to Arginine change to be damaging.

Conclusions: This study raises the interesting possibility for evaluating VAX2 as a candidate gene for cone dystrophy.     

Effects of diisopentyl phthalate exposure during gestation and lactation on hormone‐dependent behaviours and hormone receptor expression in rats

Phthalates are found in different plastic materials, such as packaging, toys and medical devices. Some of these compounds are endocrine disruptors, comprising substances that are able to induce multiple hormonal disturbances and downstream developmental effects, including the disruption of androgen‐dependent differentiation of the male reproductive tract and changes in pathways that regulate hormone‐dependent behaviours. In a previous study, metabolites of diisopentyl phthalate (DiPeP), a potent anti‐androgenic phthalate, were found in the urine of Brazilian pregnant women. Therefore, the present study aimed to evaluate the effects of DiPeP exposure during critical developmental periods on behaviours controlled by sex hormones in rats. Pregnant Wistar rats were treated with DiPeP (1, 10 or 100 mg kg day^‐1) or canola oil by oral gavage between gestational day 10 and post‐natal day (PND) 21. Male offspring were tested in a behavioural battery, including the elevated plus maze task, play behaviour, partner preference and sexual behaviour. After the behavioural tests, the hypothalamus and pituitary of these animals were removed on PND 60‐65 and PND 145‐160 to quantify gene expression for aromatase, androgen receptor (Ar) and oestrogen receptors α (Esr1) and β (Esr2). Male rats exposed to 1 and 10 mg kg day^‐1 DiPeP displayed no preference for the female stimulus rat in the partner preference test and 1 mg kg day^‐1 DiPeP rats also showed a significant increase in mount and penetration latencies when mated with receptive females. A decrease in pituitary Esr1 expression was observed in all DiPeP treated groups regardless of age. A reduction in hypothalamic Esr1 expression in rats exposed to 10 mg kg day^‐1 DiPeP was also observed. No significant changes were found with respect to Ar, Esr2 and aromatase expression in the hypothalamus. These results suggest that DiPeP exposure during critical windows of development in rats may induce changes in behaviours related to mating and the sexual motivation of males.     

Maternal and placental risk factors associated with the development of necrotizing enterocolitis (NEC) and its severity

Background/purposeAntenatal factors play an important role in NEC. This study aimed to identify antenatal risk factors associated with the development of NEC, the role of the placental alterations, and the presence of prenatal signs predisposing to a severe NEC.Materials/methodsData of NEC patients including antenatal findings [preeclampsia, diabetes, cholestasis, abnormal antenatal umbilical artery flow (AAUF), clinical chorioamnionitis (CC), and histology of placentas] were compared to unaffected cases between 2002 and 2016 in a single center. Unaffected infants were matched for gestational age. Newborns with cardiovascular diseases were excluded. Bivariate and multivariate analyses were performed.ResultsWe identified 136 cases and 134 controls. The group of mothers of NEC-neonates had a higher prevalence of preeclampsia, CC, and AAUF. Histology of Placentas from 123/136 cases and 126/133 unaffected newborns was available. Chorioamnionitis was significantly more present in NEC cases vs controls. There weren't differences in vascular anomalies and necrotic alterations. Multivariate analysis identified AAUF, CC and histological chorioamnionitis (HC) as predictors of NEC. Bivariate tests show that preeclampsia and HC occurred more often in severe cases of NEC.ConclusionThis study suggests that AAUF, CC, and HC can independently predict the risk of NEC. Preeclampsia and HC seem associated to more severe cases.Level of evidenceIIIA.