The MDM2 promoter T309G polymorphism was associated with preeclampsia susceptibility

Analysis of polymorphisms, promoter methylation, and mRNA expression profile of maternal and placental P53 and P21 genes in preeclamptic and normotensive pregnant women

Background

Preeclampsia (PE), as a multisystem disorder, is associated with maternal hypertension and proteinuria. Apoptosis seems to be involved in the pathophysiology of PE, although its precise pathogenic mechanisms are not well established. In this study, we aimed to identify the association between maternal TP53-rs1042522, P21-rs1801270, and P21-rs1059234 polymorphisms and PE. In addition, we examined the effects of promoter methylation and TP53 and P21 polymorphisms on placental mRNA expression in PE women.

Methods

The blood of 226 PE women and 228 normotensive pregnant women was examined in this study. In addition, the placentas were genotyped in 109 PE and 112 control women. The methylation status was assessed by a methylation-specific PCR assay, while mRNA expression was examined via Quantitative Real Time PCR.

Results

The maternal and placental P21-rs1801270 CA genotype had a significant association with the reduced risk of PE. In the dominant, recessive, and allelic models, maternal/placental P21-rs1059234 polymorphism had no statistically significant association with the risk of PE. On the other hand, the reduced risk of PE was associated with maternal, but not placental TP53-rs1042522 polymorphism in the dominant and recessive models. The maternal and placental P21-rs1801270 polymorphism was associated with PE risk. The maternal P21 T_rs1059234C_rs1801270 haplotype was associated with 3.4-fold increase in PE risk, However the maternal P21 T_rs1059234A_{rs 1801270} haplotype and placental C_rs1059234CA _rs1801270 haplotype led to 0.5 and 0.4-fold decrease in PE risk, respectively. PE women showed 5.6 times higher levels of placental mRNA expression of TP53 gene, although it was not associated with rs1042522 polymorphism. The relative placental mRNA expression of P21 gene was 0.2 in PE women. It was also 2.4 times higher in individuals with rs1801270CA genotype than those with AA genotype. The hyper-methylation of P21 and TP53 genes in the promoter region was associated with a 3.4-fold and 3-fold increase in PE risk, respectively. However, no association was found between P21 and TP53 mRNA expression and promoter methylation.

Conclusion

In conclusion, P21-rs1801270 and TP53-rs1042522 polymorphisms were involved in reduced risk of PE. P21-rs1801270 was associated with decreased P21 mRNA expression. The hyper-methylation of P21 and TP53 genes in the promoter region was associated with a higher PE risk.

Targeting MDM2 for novel molecular therapy: Beyond oncology

The murine double minute 2 (MDM2) oncogene exerts major oncogenic activities in human cancers; it is not only the best-documented negative regulator of the p53 tumor suppressor, but also exerts p53-independent activities. There is an increasing interest in developing MDM2-based targeted therapies. Several classes of MDM2 inhibitors have been evaluated in preclinical models, with a few entering clinical trials, mainly for cancer therapy. However, noncarcinogenic roles for MDM2 have also been identified, demonstrating that MDM2 is involved in many chronic diseases and conditions such as inflammation and autoimmune diseases, dementia and neurodegenerative diseases, heart failure and cardiovascular diseases, nephropathy, diabetes, obesity, and sterility. MDM2 inhibitors have been shown to have promising therapeutic efficacy for treating inflammation and other nonmalignant diseases in preclinical evaluations. Therefore, targeting MDM2 may represent a promising approach for treating and preventing these nonmalignant diseases. In addition, a better understanding of how MDM2 works in nonmalignant diseases may provide new biomarkers for their diagnosis, prognostic prediction, and monitoring of therapeutic outcome. In this review article, we pay special attention to the recent findings related to the roles of MDM2 in the pathogenesis of several nonmalignant diseases, the therapeutic potential of its downregulation or inhibition, and its use as a biomarker.

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.

Role of MDM2 309T>G (rs2279744) and I/D (rs3730485) polymorphisms and haplotypes in risk of papillary thyroid carcinoma, tumor stage, tumor size, and early onset of tumor: A case control study

Murine double minute clone 2 (MDM2) protein plays an important role in the regulation of p53 tumor suppressor. Genetic polymorphisms of the MDM2 gene are the candidate variants in susceptibility to various cancers. In the present study, we aimed to investigate the possible effects of MDM2 309T>G (rs2279744) and I/D (rs3730485) polymorphisms on papillary thyroid carcinoma (PTC) susceptibility and clinical or pathological features of the disease. A case control study was carried out involving in a total of 131 patients with PTC and 144 healthy controls. Both cases and controls were genotyped for MDM2 309T>G and I/D polymorphisms. There was no significant difference regarding MDM2 309T>G and I/D genotypes between patients with PTC and controls in neither dominant nor recessive and allelic models. The frequency of G-D haplotype was higher in patients with PTC and this haplotype was associated with a 1.7-fold increased risk of PTC. The MDM2 309T>G polymorphism was associated with a higher risk of III-IV stages in patients with PTC. The MDM2 ID genotype was significantly higher in patients with PTC less than 40 years and associated with larger tumor size (≥1 cm). In conclusion, the G-D haplotype but not MDM2 309T>G and I/D polymorphisms were associated with higher risk of PTC. MDM2 309T>G polymorphism was associated with a higher incidence of III-IV stages, however, I/D polymorphism was associated with larger tumor size and a lower age of disease occurrence.