Transgenic Expression of Nrf2 Induces a Pro-Reductive Stress and Adaptive Cardiac Remodeling in the Mouse.

Nuclear factor, erythroid 2 like 2 (Nfe2l2 or Nrf2), is a transcription factor that protects cells by maintaining a homeostatic redox state during stress. The constitutive expression of Nrf2 (CaNrf2-TG) was previously shown to be pathological to the heart over time. We tested a hypothesis that the cardiac-specific expression of full length Nrf2 (mNrf2-TG) would moderately increase the basal antioxidant defense, triggering a pro-reductive environment leading to adaptive cardiac remodeling. Transgenic and non-transgenic (NTG) mice at 7−8 months of age were used to analyze the myocardial transcriptome, structure, and function. Next generation sequencing (NGS) for RNA profiling and qPCR-based validation of the NGS data, myocardial redox levels, and imaging (echocardiography) were performed. Transcriptomic analysis revealed that out of 14,665 identified mRNAs, 680 were differently expressed (DEG) in TG hearts. Of 680 DEGs, 429 were upregulated and 251 were downregulated significantly (FC > 2.0, p < 0.05). Gene set enrichment analysis revealed that the top altered pathways were (a) Nrf2 signaling, (b) glutathione metabolism and (c) ROS scavenging. A comparative analysis of the glutathione redox state in the hearts demonstrated significant differences between pro-reductive vs. hyper-reductive conditions (233 ± 36.7 and 380 ± 68.7 vs. 139 ± 8.6 µM/mg protein in mNrf2-TG and CaNrf2-TG vs. NTG). Genes involved in fetal development, hypertrophy, cytoskeletal rearrangement, histone deacetylases (HDACs), and GATA transcription factors were moderately increased in mNrf2-TG compared to CaNrf2-TG. Non-invasive echocardiography analysis revealed an increase in systolic function (ejection fraction) in mNrf2-TG, suggesting an adaptation, as opposed to pathological remodeling in CaNrf2-TG mice experiencing a hyper-reductive stress, leading to reduced survival (40% at 60 weeks). The effects of excess Nrf2-driven antioxidant transcriptome revealed a pro-reductive condition in the myocardium leading to an adaptive cardiac remodeling. While pre-conditioning the myocardial redox with excess antioxidants (i.e., pro-reductive state) could be beneficial against oxidative stress, a chronic pro-reductive environment in the myocardium might transition the adaptation to pathological remodeling.

Extracellular Vesicles From Women With Severe Preeclampsia Impair Vascular Endothelial Function.

BACKGROUND: Preeclampsia (PE) manifesting as hypertension and organ injury is mediated by vascular dysfunction. In biological fluids, extracellular vesicles (EVs) containing microRNA (miRNA), protein, and other cargo released from the placenta may serve as carriers to propagate injury, altering the functional phenotype of endothelial cells. PE has been consistently correlated with increased levels of placenta-derived EVs (pEVs) in maternal circulation. However, whether pEVs impaired endothelial cell function remains to be determined. In this study, we hypothesize that pEVs from pregnant women with severe PE (sPE) impair endothelial function through altered cell signaling. METHODS: We obtained plasma samples from women with sPE (n = 14) and normotensive pregnant women (n = 15) for the isolation of EVs. The total number of EV and pEV contribution was determined by quantifying immunoreactive EV-cluster of designation 63 (CD63) and placental alkaline phosphatase (PLAP) as placenta-specific markers, respectively. Vascular endothelial functional assays were determined by cell migration, electric cell-substrate impedance sensing in human aortic endothelial cells (HAECs), and wire myography in isolated blood vessels, preincubated with EVs from normotensive and sPE women. RESULTS: Plasma EV and pEV levels were increased in sPE when compared to normotensive without a significant size distribution difference in sPE (108.8 ± 30.2 nm) and normotensive-EVs (101.3 ± 20.3 nm). Impaired endothelial repair and proliferation, reduced endothelial barrier function, reduced endothelial-dependent vasorelaxation, and decreased nitrite level indicate that sPE-EVs induced vascular endothelial dysfunction. Moreover, sPE-EVs significantly downregulated endothelial nitric oxide synthase (eNOS and p-eNOS) when compared to normotensive-EV. CONCLUSIONS: EVs from sPE women impair endothelial-dependent vascular functions in vitro.

Role of exosomal microRNA signatures: An emerging factor in preeclampsia-mediated cardiovascular disease.

Preeclampsia (PE) and vascular dysfunction are major causes of maternal and neonatal morbidity and mortality. Although extensively studied, the complete understanding of the pathophysiology behind PE remains unclear. Current reports indicate that exosomes are essential mediators in PE-related cardiovascular disease (CVDs). Exosomes are synthesized from multivesicular bodies (MVB) and contain functionally active microRNAs miRNAs). These miRNAs have been shown to mediate physiological and pathological functions through autocrine, paracrine, and endocrine signaling mechanisms. The role of miRNAs in pregnant women with PE has been studied extensively. However, little is known about the effect of exosomal miRNAs (exomiR) in PE. This paper will review and discuss the existing evidence for exomiR function in PE and highlight the need for future studies to explore the role that exomiR signatures have in cardiovascular dysfunction associated with PE.

Protective role of wild garlic on isoproterenol-induced myocardial necrosis in wistar rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Tulbaghia violacea Harv. (TVL) is a folk medicine, native to South Africa which has previously shown antioxidant, anti-hypertensive and anti-diabetic effects. THE AIM OF THE STUDY: The aim of the current study was to investigate the protective role of wild garlic or TVL on isoproterenol (ISO)-induced myocardial necrosis in rats. MATERIALS AND METHODS: Animal (n = 6 each group) were pre and co-treated with TVL (60 mg/kg body weight) daily for 30 days. Myocardial necrosis was administrated by subcutaneous injection of ISO (85 mg/kg body weight) into rats on 29th and 30th day. On the 31st day, rats were anaesthetized and blood, heart samples were obtained for the biochemical, histopathological and molecular study. The specific protein target analysis from TVL was done by reverse docking study (reverse pharmacophore mapping) using PharmMapper. RESULTS: The levels of cardiac markers, lipid peroxidation products, and heart rate were considerably increased in ISO-induced myocardial necrosis in rats whilst plasma enzymatic antioxidants were significantly decreased. Myocardial necrotic mRNA genes were increased in ISO-induced myocardial necrosis in rats compared to controls. Pre and co-treatment with TVL and ramipril of myocardial necrosis in rats showed significant effects on all the biochemical and molecular studies evaluated. TVL reduced heart rate, prevented oxidative stress and downregulated the Fas-receptor and caspase-mediated apoptosis-signaling pathway, and heart muscle damage in myocardial necrosis in rats. The specific target protein [disulfide, bis (2-sulfhydrylethyl] from TVL mediates the protective effects. CONCLUSION: Wild garlic or TVL extract has shown a protective effect on ISO-induced myocardial necrosis in rats by increasing antioxidant production confirmed with docking studies.

Angiogenic Dysregulation in Pregnancy-Related Hypertension-A Role for Metformin.

In the face of escalating maternal and fetal health threats, hypertensive pregnancy disorders (HPDs) is one of the leading cause of maternal and fetal morbidity and mortality. The range of HPDs include white-coat hypertension, chronic hypertension, gestational hypertension, mild-to-moderate and severe preeclampsia and eclampsia. Current evidence implicates an imbalance of circulating anti- and angiogenic factors in HPDs emanating from the placental vasculature, impacting on angiogenesis. Delivery of the fetus is thus far the only curative measure, albeit with increased risk. Resultant endothelial dysfunction caused by the excessive production of placental soluble fms-like tyrosine kinase-1 has been the basis of many studies to find a safer treatment strategy. Metformin, used historically in the treatment of diabetes mellitus has also found its therapeutic reach in many other disease states. These include, but are not limited to, improving blood flow in certain cancer types, treatment of polycystic ovarian disease, improving vasodilation, and reducing inflammation. Metformin is used to treat hyperglycemic endothelial dysfunction through the enhancement of the nitric oxide system, endothelin-derived hyperpolarizing factor and sirtuin 1. Similarly, endothelial dysfunction in preeclampsia and other HPDs leads to a hypoxic state and elevated blood pressures. Dubbed as the new "aspirin" of current times, the retardation of the antiangiogenic status by metformin provides an exciting and promising alternate strategy in treating these pregnancy disorders.

Differential expression of miRNAs are associated with the insulin signaling pathway in preeclampsia and gestational hypertension.

OBJECTIVES: The objective of this study was to determine microRNAs (miRNAs) expression levels in placental tissue and serum samples from preeclampsia (PE) and gestational hypertensive (GH) patients. STUDY DESIGN: Using a targeted qPCR method, the selected miRNAs putatively involved in the PE and GH were examined from normotensive (n = 32), PE (n = 32) and GH (n = 28) in South African women. Western blot analysis of protein expressions of AKT and PI3K was performed in the placental tissue of all three groups. RESULTS: qPCR results of serum miR-222 expression levels showed a significant decrease in PE compared to GH and normotensive groups. miR-29a expression levels were significantly increased in PE and GH groups compared to normotensives. Serum expression levels of miR-181a in GH showed a significant increase compared to the PE and normotensive groups. Placental tissue expression levels of miR-181a were significantly increased in PE and GH groups compared to normotensives. Western blot results of placental tissue showed a decrease in the expression levels of AKT-serine and threonine in the PE groups compared to the normotensives and a significantly higher expression in the GH groups compared to normotensives. Phosphatidyl-inositol-3 kinase (PI3K) expression levels were significantly decreased in PE and GH groups compared to normotensives. CONCLUSION: The present study, interestingly, demonstrates the differential expression of circulating miRNA in GH and a correlation between the expression levels of miRNAs with AKT/PI3K in the insulin signaling pathway, reinforcing the presence of metabolic dysregulation in PE and GH.

The effects of sildenafil citrate on urinary podocin and nephrin mRNA expression in an L-NAME model of pre-eclampsia.

We investigated the effects of sildenafil citrate (SC) on podocyturia in N ω-nitro-L-arginine methyl ester hydrochloride (L-NAME) model of pre-eclampsia (PE). One hundred and twenty Sprague-Dawley rats (SDR) were divided into five groups like pregnant control (PC), early-onset PE (EOPE), late-onset PE(LOPE), early and late-onset PE with SC-treated groups [EOPE (SC); LOPE (SC)]. PE was induced in SDR by oral administration of L-NAME in drinking water for 4-8 days for EOPE and 8-14 day for LOPE. The blood pressure, urine volume and total urine protein were increased in EOPE and LOPE groups when compared to PC, and all the above parameters decreased in EOPE (SC) and LOPE (SC) groups when compared to EOPE and LOPE groups, respectively. The EOPE and LOPE groups showed an increase in urinary nephrin mRNA and podocin mRNA levels compared to PC group. Increases in serum and renal soluble fms-like tyrosine kinase-1 (sFlt-1) expression levels and decreases in renal vascular endothelial growth factor (VEGF) expression and serum placenta growth factor (PlGF) levels were observed in EOPE and LOPE groups when compared to PC group. In addition, decreases in serum and renal sFlt-1 expression levels and increases in renal VEGF expression and serum PlGF levels were observed in EOPE (SC) and LOPE (SC) groups when compared to EOPE and LOPE groups, respectively. The light microscopy showed that the renal tissue of L-NAME-treated rats had extensive glomerular damage, tubular damage and infiltration by mononuclear cells when compared to PC group. Therefore, SC ameliorated podocyturia through its effects on the antiangiogenic/angiogenic status in this animal model.

The effects of sildenafil citrate on uterine angiogenic status and serum inflammatory markers in an L-NAME rat model of pre-eclampsia.

Pre-eclampsia (PE), a hypertensive disorder of pregnancy, is detrimental to both mother and foetus. There is currently no effective treatment, but we have shown that Sildenafil Citrate (SC) improve various foetal outcomes in Nω-nitro-L arginine methyl ester (L-NAME) rat model of PE. Therefore, we aimed to investigate the effects of SC on a uterine angiogenic status and serum inflammatory markers in an L-NAME rat model of PE. One hundred and twenty adult nulliparous pregnant female Sprague-Dawley rats were used for the study. These were divided into five equal groups; the pregnant control, early and late onset PE and respective SC treated animals. Hypertension was manifested by considerably increased systolic blood pressure and placental lipid peroxidative marker (thiobarbituric acid reactive substances) and also we assessed the activities of plasma nitric oxide level, serum inflammatory marker (TGF-ß and IFN-γ) and uterine angiogenic status (VEGF and sFlt-1) at two stages of PE. The administration of SC decreased systolic blood pressure, placental lipid peroxidation product and altered uterine angiogenic status; increased plasma nitric oxide levels in an early and late onset L-NAME model of PE. In addition, histological findings of SC treated preeclamptic rat placenta support the biochemical findings of this study. Our findings revealed that SC enhanced plasma NO levels and uterine angiogenic status in an L-NAME model of PE at two gestational stages.