Oxidative status shifts in uterine cervical incompetence patients

Oxidative stress promotes cellular damages in the cervix: implications for normal and pathologic cervical function in human pregnancy†

A physiologic increase in reactive oxygen species throughout pregnancy is required to remodel the cervix. Oxidative stress can cause cellular damage that contributes to dysfunctional tissue. This study determined the oxidative stress-induced cell fate of human cervical epithelial and cervical stromal cells. We treated the ectocervical and endocervical epithelial cells and cervical stromal cells with cigarette smoke extract, an oxidative stress inducer, for 48 h. Cell viability (crystal violet assay); cell cycle, apoptosis, and necrosis (flow cytometry); senescence (senescence-associated β-galactosidase staining); autophagy (staining for autophagosome protein, microtubule-associated protein 1 light chain 3B); stress signaler p38 mitogen-activated protein kinases pathway activation (western blot analyses); and inflammation by measuring interleukin-6 (enzyme-linked immunosorbent assay) were conducted after 48 h of cigarette smoke extract treatment. Oxidative stress induced reactive oxygen species production in cervical cells, which was inhibited by N-acetylcysteine. Oxidative stress promoted cell cycle arrest and induced necrosis in cervical cells. High senescence and low autophagy were observed in cervical stromal cells under oxidative stress. Conversely, senescence was low and autophagy was high in endocervical epithelial cells. Oxidative stress induced p38 mitogen-activated protein kinases (p38MAPK) activation in all cervical cells but only increased interleukin-6 production by the ectocervical epithelial cells. Inhibition of interleukin-6 production by a p38 mitogen-activated protein kinases inhibitor confirmed the activation of an oxidative stress-induced pathway. In conclusion, oxidative stress can promote cell death and sterile inflammation that is mediated by p38 mitogen-activated protein kinases activation in the cellular components of the cervix. These cellular damages may contribute to the normal and premature cervical ripening, which can promote preterm birth.

Individual expression features of GPX2, NQO1 and SQSTM1 transcript variants induced by hydrogen peroxide treatment in HeLa cells

Pathway activity assessment-based approaches are becoming highly influential in various fields of biology and medicine. However, these approaches mostly rely on analysis of mRNA expression, and total mRNA from a given locus is measured in the majority of cases. Notably, a significant portion of protein-coding genes produces more than one transcript. This biological fact is responsible for significant noise when changes in total mRNA transcription of a single gene are analyzed. The NFE2L2/AP-1 pathway is an attractive target for biomedical applications. To date, there is a lack of data regarding the agreement in expression of even classical target genes of this pathway. In the present paper we analyzed whether transcript variants of GPX2, NQO1 and SQSTM1 were characterized by individual features of expression when HeLa cells were exposed to pro-oxidative stimulation with hydrogen peroxide. We found that all the transcripts (10 in total) appeared to be significantly individually regulated under the conditions tested. We conclude that individual transcripts, rather than total mRNA, are best markers of pathway activation. We also discuss here some biological roles of individual transcript regulation.

Oxidative stress in pregnancy and reproduction

Oxidative stress is implicated in the pathophysiology of many reproductive complications including infertility, miscarriage, pre-eclampsia, fetal growth restriction and preterm labour. The presence of excess reactive oxygen species can lead to cellular damage of deoxyribonucleic acids, lipids and proteins. Antioxidants protect cells from peroxidation reactions, limiting cellular damage and helping to maintain cellular membrane integrity. There is overwhelming evidence for oxidative stress causing harm in reproduction. However, there is sparse evidence that supplementation with commonly used antioxidants (mostly vitamins C and E) makes any difference in overcoming oxidative stress or reversing disease processes. There may be potential for antioxidant therapy to ameliorate or prevent disease, but this requires a thorough understanding of the mechanism of action and specificity of currently used antioxidants.