Lipopolysaccharide induces nitric oxide synthase expression and platelet-activating factor increases nitric oxide production in human fetal membranes in culture

Cytokine-induced expression of nitric oxide synthases in Chlamydia trachomatis-infected spontaneous aborters

Purpose: The aim of study was to evaluate expression of inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) in Chlamydia trachomatis (CT)-infected spontaneous aborters (SA). Materials and methods: Endometrial curettage tissue was collected from 140 SA (sporadic SA- 70; recurrent SA- 70) (Group I) and 140 age-matched controls (Group II) from Department of Obstetrics and Gynecology, Safdarjung Hospital, New Delhi, India. Polymerase chain reaction was performed for diagnosis of CT. The expression of iNOS/ eNOS/ IFN-γ/ TNF-α was assessed by real-time polymerase chain reaction (PCR). Results: 15.7% SA were CT-positive (Group I); none in controls. Sporadic spontaneous aborters (SSA) (n = 8/70), recurrent spontaneous aborters (RSA) (n = 14/70) diagnosed as CT-positive (Group-I). Significant upregulation of iNOS/ eNOS was found in CT-positive SSA/RSA compared with CT-negative SSA/RSA and healthy controls. TNF-α and IFN-γ were expressed in CT-positive SSA/RSA compared with negative SSA/controls. iNOS showed a significant strong positive correlation with TNF-α and IFN-γ in CT-infected SA. eNOS showed a significant positive correlation with TNF-α and no correlation with IFN-γ in CT-infected SA. TNF-α was positively correlated with IFN-γ. Conclusions: Significantly high expression of iNOS/ eNOS and proinflammatory cytokines affected pregnancy in CT-infected RSA, thereby implying that there occurs cytokine-induced expression of nitric oxide synthase (NOS).

Argininosuccinate synthetase 1 depletion produces a metabolic state conducive to herpes simplex virus 1 infection

Herpes simplex virus 1 (HSV-1) infection triggers specific metabolic changes in its host cell. To explore the interactions between cellular metabolism and HSV-1 infection, we performed an siRNA screen of cellular metabolic genes, measuring their effect on viral replication. The screen identified multiple enzymes predicted to influence HSV-1 replication, including argininosuccinate synthetase 1 (AS1), which consumes aspartate as part of de novo arginine synthesis. Knockdown of AS1 robustly enhanced viral genome replication and the production of infectious virus. Using high-resolution liquid chromatography-mass spectrometry, we found that the metabolic phenotype induced by knockdown of AS1 in human fibroblasts mimicked multiple aspects of the metabolic program observed during HSV-1 infection, including an increase in multiple nucleotides and their precursors. Together with the observation that AS1 protein and mRNA levels decrease during wild-type infection, this work suggests that reduced AS1 activity is partially responsible for the metabolic program induced by infection.

Role of oxidative stress in female reproduction

In a healthy body, ROS (reactive oxygen species) and antioxidants remain in balance. When the balance is disrupted towards an overabundance of ROS, oxidative stress (OS) occurs. OS influences the entire reproductive lifespan of a woman and even thereafter (i.e. menopause). OS results from an imbalance between prooxidants (free radical species) and the body's scavenging ability (antioxidants). ROS are a double-edged sword - they serve as key signal molecules in physiological processes but also have a role in pathological processes involving the female reproductive tract. ROS affect multiple physiological processes from oocyte maturation to fertilization, embryo development and pregnancy. It has been suggested that OS modulates the age-related decline in fertility. It plays a role during pregnancy and normal parturition and in initiation of preterm labor. Most ovarian cancers appear in the surface epithelium, and repetitive ovulation has been thought to be a causative factor. Ovulation-induced oxidative base damage and damage to DNA of the ovarian epithelium can be prevented by antioxidants. There is growing literature on the effects of OS in female reproduction with involvement in the pathophysiology of preeclampsia, hydatidiform mole, free radical-induced birth defects and other situations such as abortions. Numerous studies have shown that OS plays a role in the pathophysiology of infertility and assisted fertility. There is some evidence of its role in endometriosis, tubal and peritoneal factor infertility and unexplained infertility. This article reviews the role OS plays in normal cycling ovaries, follicular development and cyclical endometrial changes. It also discusses OS-related female infertility and how it influences the outcomes of assisted reproductive techniques. The review comprehensively explores the literature for evidence of the role of oxidative stress in conditions such as abortions, preeclampsia, hydatidiform mole, fetal embryopathies, preterm labour and preeclampsia and gestational diabetes. The review also addresses the growing literature on the role of nitric oxide species in female reproduction. The involvement of nitric oxide species in regulation of endometrial and ovarian function, etiopathogenesis of endometriosis, and maintenance of uterine quiescence, initiation of labour and ripening of cervix at parturition is discussed. Complex interplay between cytokines and oxidative stress in the etiology of female reproductive disorders is discussed. Oxidant status of the cell modulates angiogenesis, which is critical for follicular growth, corpus luteum formation endometrial differentiation and embryonic growth is also highlighted in the review. Strategies to overcome oxidative stress and enhance fertility, both natural and assisted are delineated. Early interventions being investigated for prevention of preeclampsia are enumerated. Trials investigating combination intervention strategy of vitamin E and vitamin C supplementation in preventing preeclampsia are highlighted. Antioxidants are powerful and there are few trials investigating antioxidant supplementation in female reproduction. However, before clinicians recommend antioxidants, randomized controlled trials with sufficient power are necessary to prove the efficacy of antioxidant supplementation in disorders of female reproduction. Serial measurement of oxidative stress biomarkers in longitudinal studies may help delineate the etiology of some of the diosorders in female reproduction such as preeclampsia.