AEBP1gene variants in infants with gastroschisis

Inactive metallopeptidase homologs: the secret lives of pseudopeptidases

Inactive enzyme homologs, or pseudoenzymes, are proteins, found within most enzyme families, that are incapable of performing catalysis. Rather than catalysis, they are involved in protein-protein interactions, sometimes regulating the activity of their active enzyme cousins, or scaffolding protein complexes. Pseudoenzymes found within metallopeptidase families likewise perform these functions. Pseudoenzymes within the M14 carboxypeptidase family interact with collagens within the extracellular space, while pseudopeptidase members of the M12 "a disintegrin and metalloprotease" (ADAM) family either discard their pseudopeptidase domains as unnecessary for their roles in sperm maturation or utilize surface loops to enable assembly of key complexes at neuronal synapses. Other metallopeptidase families contain pseudopeptidases involved in protein synthesis at the ribosome and protein import into organelles, sometimes using their pseudo-active sites for these interactions. Although the functions of these pseudopeptidases have been challenging to study, ongoing work is teasing out the secret lives of these proteins.

Factors associated with maternal consent for use of residual newborn bloodspots in the National Birth Defects Prevention Study

PURPOSE

We investigated factors associated with maternal consent to use residual newborn dried bloodspots (DBS) in a national case-control study of birth defects.

METHODS

A subset of sites in the National Birth Defects Prevention Study (NBDPS; 1997-2011) asked participants to provide consent for investigators to retrieve DBS from local newborn screening programs to use for research on risk factors for birth defects. We assessed whether consent differed by factors including maternal age, education, parity, body mass index, language of interview, country of birth, and case-control status.

RESULTS

Of 5,850 mothers of cases and 2,534 mothers of controls, 57% provided consent for the DBS component. Mothers of cases were more likely to participate than mothers of controls (61% vs. 52%), as were mothers who self-reported white race, >12 years of education, and born in the United States.

CONCLUSIONS

Retrieval of DBS can be integrated into retrospective studies of neonatal outcomes including birth defects. In NBDPS, participation in the DBS component was moderate and varied by some sociodemographic factors. Further research is needed to better understand families' perspectives on using residual DBS for secondary research. Representative participation is important to reduce the potential for selection bias in future studies using DBS for children's health research.

Fetal gastroschisis: Maternal and fetal methylation profile

OBJECTIVE

The purpose of this study was to describe the genomic deoxyribonucleic acid (DNA) methylation profile in fetuses with gastroschisis, determine whether the profile was inherited, and investigate any possible correlations with maternal risk factors.

METHOD

Genome-wide DNA methylation analysis of 96 blood samples was performed using the Illumina Human Methylation 850K BeadChip. The blood samples were collected as follows: 32 from the umbilical cord of fetuses with gastroschisis, 32 from their respective mothers, 16 from the umbilical cord of fetuses without malformation, and 16 from their respective mothers.

RESULTS

The differential DNA methylation analysis showed a significant difference between the groups. The enrichment analysis resulted in 12 sites related to T-cell activation (p = 0.0128). The sites with different methylation status contained 10 genes, three of which were related to the beta-2-microglobulin gene. The methylation profile observed in the fetuses with gastroschisis was not inherited from the mothers. In addition, there was no association between maternal urinary tract infection, smoking, and alcohol use and different methylated sites.

CONCLUSION

We established the methylation profile of gastroschisis fetuses, which differs from that of normal fetuses. The profile was not inherited and did not correlate with maternal risk factors.

Insights into the etiology and embryology of gastroschisis

The development of gastroschisis has long remained an area of interest and controversy. Successive theories about its pathogenesis are herein reviewed and discussed. Two historical assumptions, that omphalocele results from a persistent umbilical hernia, and that gastroschisis does not involve the umbilical cord, are dismissed. Therefore, one can envision gastroschisis for what it is, i.e. a ruptured physiological hernia. The causal agents for this intrauterine accident to occur are yet to be determined. Further bowel damage and complications can be explained by the mesenteric insult.

Genetic variants conferring susceptibility to gastroschisis: a phenomenon restricted to the interaction with the environment?

BACKGROUND

Genes involved in gastroschisis have shown a strong interaction with environmental factors. However, less is known about its influence. We aimed to systematically review the genetic associations of gastroschisis, to summarize whether its genetic susceptibility has been restricted to the interaction with the environment, and to identify significant gaps that remain for consideration in future studies.

METHODS

Genetic association studies of gastroschisis published 1980-2017 (PubMed/MEDLINE) were independently searched by two reviewers. Significant SNP-gastroschisis associations were grouped into crude and stratified risks, whereas SNPs were assessed from two or more independent studies. Frequencies, odds ratios, and 95% confidence intervals were pooled using descriptive analysis and Chi-square test accounting for heterogeneity.

RESULTS

Seven eligible articles capturing associations of 14 SNPs from 10 genes for crude risk (including 10 and 4 SNPs with increased and decreased risk, respectively) and 30 SNPs from 14 genes for stratified risk in gastroschisis (including 37 and 14 SNPs with increased and decreased risk, respectively) were identified (Fisher's exact test, P = 0.438). The rs4961 (ADD1), rs5443 (GNB3), rs1042713, and rs1042714 (ADRB2) were significantly associated with gastroschisis.

CONCLUSIONS

Genetic susceptibility in gastroschisis is not restricted to the interaction with the environment and should not be too narrowly focused on environmental factors. We found significant associations with four SNPs from three genes related to blood pressure regulation, which supports a significant role of vascular disruption in the pathogenesis of gastroschisis. Future studies considering gene-gene or gene-environmental interactions are warranted for better understanding the etiology of gastroschisis.

Antibody profiling identifies novel antigenic targets in spinal cord injury patients

Background

Recent evidence implicates antibody responses as pivotal damaging factors in spinal cord injury (SCI)-induced neuroinflammation. To date, only a limited number of the antibody targets have been uncovered, and the discovery of novel targets with pathologic and clinical relevance still represents a major challenge.

Methods

In this study, we, therefore, applied an unbiased, innovative and powerful strategy, called serological antigen selection (SAS), to fully identify the complex information present within the antibody repertoire of SCI patients.

Results

We constructed a high-quality cDNA phage display library derived from human spinal cord tissue to screen for antibody reactivity in pooled plasma samples from traumatic SCI patients (n = 10, identification cohort). By performing SAS, we identified a panel of 19 antigenic targets to which the individual samples of the plasma pool showed antibody reactivity. Sequence analysis to identify the selected antigenic targets uncovered 5 known proteins, to which antibody reactivity has not been associated with SCI before, as well as linear peptides. Immunoreactivity against 9 of the 19 novel identified targets was validated in 41 additional SCI patients and an equal number of age- and gender-matched healthy subjects. Overall, we found elevated antibody levels to at least 1 of the 9 targets in 51 % of our total SCI patient cohort (n = 51) with a specificity of 73 %. By combining 6 of these 9 targets into a panel, an overall reactivity of approximately half of the SCI patients could be maintained while increasing the specificity to 82 %.

Conclusions

In conclusion, our innovative high-throughput approach resulted in the identification of previously unexplored antigenic targets with elevated immunoreactivity in more than 50 % of the SCI patients. Characterization of the validated antibody responses and their targets will not only provide new insight into the underlying disease processes of SCI pathology but also significantly contribute to uncovering potential antibody biomarkers for SCI patients.

Gene variants as risk factors for gastroschisis

In a population‐based case‐control study in California of 228 infants, we investigated 75 genetic variants in 20 genes and risk of gastroschisis with regard to maternal age, race/ethnicity, vitamin use, and smoking exposure. We hypothesized that genes related to vascular compromise may interact with environmental factors to affect the risk of gastroschisis. Haplotypes were constructed for 75 gene variants using the HaploView program. Risk for gastroschisis associated with each gene variant was calculated for both the homozygotes and the heterozygotes, with the homozygous wildtypes as the referent. Risks were estimated as odds ratios (ORs) with 95% confidence intervals (CIs) by logistic regression. We found 11 gene variants with increased risk and four variants with decreased risk of gastroschisis for heterozygous (OR_h) or homozygous variants (OR_v) genotypes. These included NOS3 (rs1036145) OR_h = 0.4 (95% CI: 0.2–0.7); NOS3 (rs10277237) OR_v = 2.7 (95% CI: 1.3–6.0); ADD1 (rs12503220) OR_h = 2.9 (95% CI: 1.6–5.4), GNB3 (rs5443) OR_h = 0.2 (95% CI: 0.1–0.5), OR_v = 0.4 (95% CI: 0.2–0.9); ICAM1 (rs281428) OR_v = 6.9 (95% CI: 2.1–22.9), ICAM1 (rs3093030) OR_v = 2.6 (95% CI: 1.2–5.6); ICAM4 (rs281438) OR_v = 4.9 (95% CI: 1.4–16.6), ICAM5 (rs281417) OR_h = 2.1 (95% CI: 1.1–4.1), OR_v = 4.8 (95% CI: 1.7–13.6); ICAM5 (rs281440) OR_h = 23.7 (95% CI: 5.5–102.5), OR_v = 20.6 (95% CI: 3.4–124.3); ICAM5 (rs2075741) OR_v = 2.2 (95% CI: 1.1–4.4); NAT1 OR_v = 0.3 (95% CI: 0.1–0.9). There were additional associations between several gene variants and gastroschisis among women aged 20–24 and among mothers with and without vitamin use. NOS3, ADD1, ICAM1, ICAM4, and ICAM5 warrant further investigation in additional populations and with the interaction of additional environmental exposures. © 2016 Wiley Periodicals, Inc.

Maternal smoking, xenobiotic metabolizing enzyme gene variants, and gastroschisis risk

Maternal smoking during pregnancy is one proposed risk factor for gastroschisis, but reported associations have been modest, suggesting that differences in genetic susceptibility might play a role. We included 108 non-Hispanic white and 62 Hispanic families who had infants with gastroschisis, and 1,147 non-Hispanic white and 337 Hispanic families who had liveborn infants with no major structural birth defects (controls) in these analyses. DNA was extracted from buccal cells collected from infants and mothers, and information on periconceptional smoking history was obtained from maternal interviews, as part of the National Birth Defects Prevention Study. We analyzed five polymorphisms in three genes that code for enzymes involved in metabolism of some cigarette smoke constituents (CYP1A1, CYP1A2, and NAT2). Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) independently for maternal smoking and maternal and infant gene variants, and to assess joint associations of maternal smoking and maternal or infant gene variants with gastroschisis. In analyses adjusted for maternal age at delivery and stratified by maternal race-ethnicity, we identified three suggestive associations among 30 potential associations with sufficient numbers to calculate ORs: CYP1A1*2A for non-Hispanic white mothers who smoked periconceptionally (aOR = 0.38, 95% CI 0.15-0.98), and NAT2*6 for Hispanic non-smoking mothers (aOR = 2.17, 95% CI 1.12-4.19) and their infants (aOR = 2.11, 95% CI 1.00-4.48). This analysis does not support the occurrence of effect modification between periconceptional maternal smoking and most of the xenobiotic metabolizing enzyme gene variants assessed.