Polymorphisms in DNA repair genes (APEX1, XPD, XRCC1 and XRCC3) and risk of preeclampsia in a Mexican mestizo population

Optimizing the Comet Assay-Based In Vitro DNA Repair Assay for Placental Tissue: A Pilot Study with Pre-Eclamptic Patients

The comet assay-based in vitro DNA repair assay has become a common tool for quantifying base excision repair (BER) activity in human lymphocytes or cultured cells. Here, we optimized the protocol for studying BER in human placental tissue because the placenta is a non-invasive tissue for biomonitoring of early-life exposures, and it can be used to investigate molecular mechanisms associated with prenatal disorders. The optimal protein concentration of placental protein extracts for optimal damage recognition and incision was 2 mg protein/mL. The addition of aphidicolin did not lead to reduced non-specific incisions and was, therefore, not included in the optimized protocol. The interval between sample collection and analysis did not affect BER activity up to 70 min. Finally, this optimized protocol was tested on pre-eclamptic (PE) placental tissues (n = 11) and significantly lower BER activity in PE placentas compared to controls (n = 9) was observed. This was paralleled by a significant reduction in the expression of BER-related genes and increased DNA oxidation in PE placentas. Our study indicates that BER activity can be determined in placentas, and lower activity is present in PE compared with healthy. These findings should be followed up in prospective clinical investigations to examine BER's role in the advancement of PE.

Apurinic/apyrimidinic endonuclease 1 mRNA level in peripheral blood neutrophils is associated with asthma

Apurinic/apyrimidinic endonuclease 1 (APE1) is a multifunc-tional key protein. Recent studies suggest APE1 is closely associated with in-flammatory response, but its role in asthma remains unknown. We recruited 116 patients with asthma, including 50 with severe asthma (NSA) and 66 with non-severe asthma (SA), and 140 controls. Serum APE1 was detected using the ELISA method. APE1 mRNA in peripheral blood neutrophils and eosinophils were detected using real-time PCR assays. Compared to healthy controls, we observed significant elevations of serum APE1 mRNA levels in peripheral neu-trophils (~1.75 folds increase, p<0.05) and eosinophils (~2.2 folds increase, p<0.05) in patients with asthma. The peripheral blood neutrophil APE1 mRNA can distinguish asthmatic patients from healthy controls with the area under the curve (AUC) 0.893 and a 95% confidence interval (CI) 0.847-0.938 (p < 0.001). Also the APE1 mRNA can identify severe asthma from non-severe asth-ma (AUC 0.759, 95% CI, 0.674-0.846; p < 0.001). However, The serum APE1 and eosinophil mRNA levels did not correlate with asthma incidence and sever-ity. Our finding confirms the association between APE1 and asthma and sug-gests that peripheral blood neutrophil APE1 mRNA may be used as a marker for this condition.

Dynamics of DNA damage response markers, RAD51 and XRCC1, throughout the menstrual cycle and pregnancy in healthy women. Increment during pregnancy and relation to a low titer of antinuclear antibodies

PROBLEM

Antinuclear antibodies (ANA) potentially play a role in the pathogenesis of connective tissue diseases (CTDs); however, they are also detected in healthy individuals. Our understanding of the physiological and pathological origin of ANA is incomplete. Both; female reproductive processes and deficiencies in DNA damage response (DDR) have been independently associated with ANA production. However, the link between these two factors and the presence of ANA is unclear METHOD OF STUDY: A cohort study was conducted on 87 non-pregnant and 51 healthy pregnant women. ANA and the DDR markers X-ray repair cross-complementing 1 (XRCC1) and recombinase (RAD51) were quantified in sera by enzyme-linked immunosorbent assay. Additionally, ANA was detected by indirect immunofluorescence in HEp-2 cells in 1:40 diluted sera during the three phases of the menstrual cycle in non-pregnant women and every trimester in pregnant women RESULTS: The prevalence of ANA+ in healthy women was 26.1%, with no significant differences between pregnant and non-pregnant women. ANA and DDR marker levels did not vary among the three phases of the menstrual cycle or the three trimesters of pregnancy. However, DDR marker levels were higher in pregnant women than in non-pregnant women (p<0.001) and were found to be higher in ANA+ women (XRCC1, p = 0.025; RAD51, p = 0.006) CONCLUSIONS: The menstrual cycle and pregnancy did not influence the levels of DDR markers or ANA in healthy women; however, the DDR was higher in pregnancy and ANA+ women. The results suggest a potential role of DDR in the pathophysiology of ANA. This article is protected by copyright. All rights reserved.

Association between polymorphisms rs2228001 and rs2228000 in XPC and genetic susceptibility to preeclampsia: a case control study

BACKGROUND

Xeroderma pigmentosum complementation group C (XPC) is a DNA damage recognition protein that plays an important role in nucleotide excision repair and can reduce oxidative stress, which may be involved in the development of preeclampsia (PE). Therefore, the aim of this study was to explore whether XPC polymorphisms were relevant to the genetic susceptibility to PE in Chinese Han women.

METHOD

A total of 1276 healthy pregnant women were included as the control group and 958 pregnant women with PE as the case group. DNA was extracted from peripheral blood samples to perform genotyping of loci rs2228001 and rs2228000 in XPC through real-time quantitative polymerase chain reaction (PCR). The relationship between XPC and susceptibility to PE was evaluated by comparing the genotypic and allelic frequencies between the two groups of pregnant women.

RESULTS

Polymorphism of rs2228000 may be associated with PE risk and allele T may play a protective role (genotype, χ2 = 38.961, P < 0.001 and allele χ2 = 21.746 P < 0.001, odds ratio (OR) = 0.885, 95% confidence interval (CI) = 0.840-0.932). No significant difference was found between the two groups in rs2228001,(genotype χ2 = 3.148, P = 0.207 and allele χ2 = 0.59, P = 0.442, OR = 1.017, 95% CI = 0.974-1.062). When the frequencies of genotypes and alleles for early- and late-onset PE, mild PE and severe PE were compared with those of controls, the results were consistent with the large clinical sample.

CONCLUSION

Our data suggest that the genetic variant rs2228000 in XPC may be associated with PE risk in Chinese Han women, and that pregnant women with the TT genotype have a reduced risk of PE. Further investigations are needed to confirm these findings in other regions or larger prospective populations.

Genetic Variants in Preeclampsia: Lessons From Studies in Latin-American Populations

Placental vascularization is a tightly regulated physiological process in which the maternal immune system plays a fundamental role. Vascularization of the maternal-placental interface involves a wide range of mechanisms primarily orchestrated by the fetal extravillous trophoblast and maternal immune cells. In a healthy pregnancy, an immune cross-talk between the mother and fetal cells results in the secretion of immunomodulatory mediators, apoptosis of specific cells, cellular differentiation/proliferation, angiogenesis, and vasculogenesis, altogether favoring a suitable microenvironment for the developing embryo. In the context of vasculopathy underlying common pregnancy disorders, it is believed that inefficient invasion of extravillous trophoblast cells in the endometrium leads to a poor placental blood supply, which, in turn, leads to decreased secretion of angiogenic factors, hypoxia, and inflammation commonly associated with preterm delivery, intrauterine growth restriction, and preeclampsia. In this review, we will focus on studies published by Latin American research groups, providing an extensive review of the role of genetic variants from candidate genes involved in a broad spectrum of biological processes underlying the pathophysiology of preeclampsia. In addition, we will discuss how these studies contribute to fill gaps in the current understanding of preeclampsia. Finally, we discuss some trending topics from important fields associated with pregnancy vascular disorders (e.g., epigenetics, transplantation biology, and non-coding RNAs) and underscore their possible implications in the pathophysiology of preeclampsia. As a result, these efforts are expected to give an overview of the extent of scientific research produced in Latin America and encourage multicentric collaborations by highlighted regional research groups involved in preeclampsia investigation.

Arginine vasopressin infusion is sufficient to model clinical features of preeclampsia in mice

Copeptin, a marker of arginine vasopressin (AVP) secretion, is elevated throughout human pregnancies complicated by preeclampsia (PE), and AVP infusion throughout gestation is sufficient to induce the major phenotypes of PE in mice. Thus, we hypothesized a role for AVP in the pathogenesis of PE. AVP infusion into pregnant C57BL/6J mice resulted in hypertension, renal glomerular endotheliosis, intrauterine growth restriction, decreased placental growth factor (PGF), altered placental morphology, placental oxidative stress, and placental gene expression consistent with human PE. Interestingly, these changes occurred despite a lack of placental hypoxia or elevations in placental fms-like tyrosine kinase-1 (FLT1). Coinfusion of AVP receptor antagonists and time-restricted infusion of AVP uncovered a mid-gestational role for the AVPR1A receptor in the observed renal pathologies, versus mid- and late-gestational roles for the AVPR2 receptor in the blood pressure and fetal phenotypes. These findings demonstrate that AVP is sufficient to initiate phenotypes of PE in the absence of placental hypoxia, and indicate that AVP may mechanistically (independently, and possibly synergistically with hypoxia) contribute to the development of clinical signs of PE in specific subtypes of human PE. Additionally, they identify divergent and gestational time-specific signaling mechanisms that mediate the development of PE phenotypes in response to AVP.

Association of nineteen polymorphisms from seven DNA repair genes and the risk for bladder cancer in Gansu province of China

Background

Balance of DNA damage and proper repair plays an important role in progression of bladder cancer. Here we aimed to assess the associations of nineteen polymorphisms from seven DNA repair–associated genes (PRAP1, OGG1, APEX1, MUTYH, XRCC1, XRCC2 and XRCC3) with bladder cancer and their interactions in the disease in a Han Chinese population.

Methodology/Principal Findings

A chip-based TaqMan genotyping for the candidate genes was performed on 227 bladder cancer patients and 260 healthy controls. APEX1 rs3136817, MUTYH rs3219493, three SNPs (rs3213356, rs25487 and rs1799782) in XRCC1, and three SNPs (rs1799794, rs861531 and rs861530) in XRCC3 showed significant associations with the risk of bladder cancer. In haplotype analysis, elevated risks of bladder cancer were observed in those with either haplotype GT (OR = 1.56, P = 0.003) of APEX1, or GGGTC (OR = 2.05, P = 0.002) of XRCC1, whereas decreased risks were in individuals with either GCGCC (OR = 0.40, P = 0.001), or GCGTT (OR = 0.60, = 0.005) of XRCC1, or CCC (OR = 0.65, P = 0.004) of MUTYH, or TTTAT (OR = 0.36, P = 0.009) of XRCC3. Interaction analysis showed that the two-loci model (rs1799794 and rs861530) was the best with the maximal testing accuracy of 0.701, and the maximal 100% cross-validation consistency (P = 0.001).

Conclusions

Polymorphisms and haplotypes of DNA repair genes are associated with the risk of bladder cancer, and of which the SNPs (rs1799794 and rs861530) in XRCC3 gene might be two major loci in relation to the susceptibility to bladder cancer in a northwest Chinese population.

Polymorphism of ERCC1 rs3212986 in Chinese Han women with preeclampsia

OBJECTIVE

To investigate the association between polymorphism of rs3212986 in ERCC1 and susceptibility to preeclampsia in the Chinese Han population.

STUDY DESIGN

Samples of 642 preeclampsia patients and 877 controls were genotyped for rs3212986 using TaqMan allele discrimination assays. The genetic and allelic distributions between the groups were compared by Pearson's χ² test.

RESULT

There was no difference in the genotypic and allelic distributions between cases and controls (P>0.05). Statistical difference in genotypic frequencies of rs3212986 was observed between early-onset and late-onset preeclampsia (χ²=6.985, P=0.030). When subdivided into TT/GG+GT groups, a significant difference was found between early-onset and late-onset preeclampsia (χ²=6.528, P=0.011, OR=2.011, 95%CI 1.167-3.465).

CONCLUSION

The polymorphisms of rs3212986 showed no association with the risk of preeclampsia in the Chinese Han population. However, the difference in the genotypic distribution between early-onset and late-onset preeclampsia suggest the need for future studies.