Bioflavonoid luteolin prevents sFlt-1 release via HIF-1α inhibition in cultured human placenta

Luteolin: A promising multifunctional natural flavonoid for human diseases

Natural products are closely associated with human health. Luteolin (LUT), a flavonoid polyphenolic compound, is widely found in fruits, vegetables, flowers, and herbs. It is noteworthy that LUT exhibits a variety of beneficial pharmacological properties and holds significant potential for clinical applications, particularly in antitumor, anti-convulsion, diabetes control, anti-inflammatory, neuroprotection, anti-oxidation, anti-cardiovascular, and other aspects. The potential mechanism of action has been partially elucidated, including the mediation of NF-κB, toll-like receptor, MAPK, Wnt/β-catenin, PI3K/Akt, AMPK/mTOR, and Nrf-2, among others. The review that aimed to comprehensively consolidate essential information on natural sources, pharmacological effects, therapeutic and preventive potential, as well as potential mechanisms of LUT. The objective is to establish a theoretical basis for the continued development and application of LUT.

Soyghurt Potentially Controls the Level of sFlt1 and PLGF in Preeclampsia Maternal Serum-Induced Placental Trophoblast Cell in vitro

Purpose

To observe the effect of soya yoghurt (Soyghurt), which is high in flavonoid substance, on the expression of preeclampsia biomarkers (sFLT-1 and PLGF) on preeclampsia serum-induced trophoblast primary cell culture isolated from placental tissue.

Methods

The trophoblast primary culture was induced by preeclampsia serum (10%). The Soyghurt treatment was performed with 2.5%, 5%, and 7.5% Soyghurt supernatant concentrations in culture media. The expression of preeclampsia markers, sFLT-1 and PLGF, were evaluated using ELISA.

Results

Expression of sFLT-1 on preeclampsia-induced cell culture treated with Soyghurt was significantly lowered compared to the untreated group (p<0.01). However, no significant difference was observed in the PLGF levels of all groups induced by preeclampsia serum (p>0.05).

Conclusion

This study demonstrates the potential effect of Soyghurt's in balancing preeclampsia marker expression by inhibiting the expression of sFLT-1 in preeclampsia serum -induced trophoblast cells.

Placental and Renal Pathways Underlying Pre-Eclampsia

Pre-eclampsia is a serious complication of pregnancy characterized by a state of multiorgan hypertensive disorders, with or without proteinuria and possible multiorgan dysfunction. Chronic kidney disease is an established risk factor for the development of pre-eclampsia, as angiogenic homeostasis is altered and the maternal circulation is already hypertensive. Facing pre-eclampsia in the context of chronic kidney disease is a challenging emergency for both the mother and the fetus. The clinical features and the management of this multi-organ disorder are clearly defined in the modern literature but the underlying pathophysiologic mechanisms remain not fully elucidated. Understanding the pathophysiology that mediates the onset of pre-eclampsia itself and in synergy with chronic kidney disease is fundamental for developing prompt prevention strategies, treatment planning, and patient counseling. This review aims to summarize the main molecular mechanisms involved in the process of pre-eclampsia, with a particular focus on the role of the kidneys and hormonal pathways related to renal function in normal pregnancy and pre-eclamptic syndromes.

Translation of mechanistic advances in preeclampsia to the clinic: Long and winding road

As one of the leading causes of premature birth and maternal and infant mortality worldwide, preeclampsia remains a major unmet public health challenge. Preeclampsia and related hypertensive disorders of pregnancy are estimated to cause >75 000 maternal and 500 000 infant deaths globally each year. Because of rising rates of risk factors such as obesity, in vitro fertilization and advanced maternal age, the incidence of preeclampsia is going up with rates ranging from 5% to 10% of all pregnancies worldwide. A major discovery in the field was the realization that the clinical phenotypes related to preeclampsia, such as hypertension, proteinuria, and other adverse maternal/fetal events, are due to excess circulating soluble fms-like tyrosine kinase-1 (sFlt-1, also referred to as sVEGFR-1). sFlt-1 is an endogenous anti-angiogenic protein that is made by the placenta and acts by neutralizing the pro-angiogenic proteins vascular endothelial growth factor (VEGF) and placental growth factor (PlGF). During the last decade, this work has spawned a new era of molecular diagnostics for early detection of this condition. Antagonizing sFlt-1 either by reducing production or blocking its actions has shown salutary effects in animal models. Further, in early-stage human studies, the therapeutic removal of sFlt-1 from maternal circulation has shown promise in delaying disease progression and improving outcomes. Recently, the FDA approved the first molecular test for preterm preeclampsia (sFlt-1/PlGF ratio) for clinical use in the United States. Measuring serum sFlt-1/PlGF ratio in the acute hospital setting may aid short-term management, particularly regarding step-up or step-down of care, decision to transfer to settings better equipped to manage both the mother and the preterm neonate, appropriate timing of administration of steroids and magnesium sulfate, and in expectant management decisions. The test itself has the potential to save lives. Furthermore, the availability of a molecular test that correlates with adverse outcomes has set the stage for interventional clinical trials testing treatments for this disorder. In this review, we will discuss the role of circulating sFlt-1 and related factors in the pathogenesis of preeclampsia and specifically how this discovery is leading to concrete advances in the care of women with preeclampsia.

Autophagy-related biomarkers in preeclampsia: the underlying mechanism, correlation to the immune microenvironment and drug screening

BACKGROUND

Preeclampsia is a life-threatening disease of pregnancy that lacks effective pharmaceuticals which can target its pathogenesis. Since preeclampsia involves complex pathological processes, including autophagy, this study aims to explore autophagy-related mechanisms of preeclampsia and to screen potential drugs.

METHODS

Firstly, the datasets GSE75010, GSE24129, GSE66273, and autophagic genes lists were downloaded from public databases. Then, a weighted gene co-expression network analysis (WGCNA) was applied to filter autophagic-related hub genes of preeclampsia. The differential expression levels of the hub genes were validated with datasets GSE24129 and GSE66273. Next, the GO and KEGG enrichment, protein-protein interacting (PPI) network, as well as the downstream pathways was analyzed via the starBase, STRING and Cytoscape to determine the functions and regulatory network of the hub genes. Additionally, the immune microenvironment of preeclampsia was investigated by the CIBERSORTX database. Finally, three herb ingredients, berberine, baicalein, and luteolin were screened by molecular docking in comparison to pravastatin, metformin, and aspirin, to predict potential drugs for treating preeclampsia.

RESULTS

A total of 54 autophagy-related genes were filtered by WGCNA. After filtering with |GS| > 0.5 and |MM| > 0.8, three hub genes, namely PKM, LEP, and HK2, were identified and validated. Among these genes, PKM and LEP were overexpressed in women older than 35 years old ( p<0.05; p<0.05); the expression of PKM, LEP, and HK2 differed remarkably in women with different BMI (all p<0.05); PKM overexpressed in women with hypertension (p<0.05). The regulatory network of hub genes demonstrated that they were mainly enriched in metabolic pathways, including the AMPK signaling pathway, glucagon signaling pathway, adipocytokine signaling pathway, and central carbon metabolism. Then, immune microenvironment analysis turned out that M2 macrophages were reduced in preeclampsia women (p<0.0001) and were negatively correlated with the expression of PKM (r=-0.2, p<0.05), LEP (r=-0.4, p<0.0001), and HK2 (r=-0.3, p<0.001). Lastly, molecular docking showed baicalein and luteolin could bind intimately to hub genes.

CONCLUSION

PKM, LEP, and HK2 could be promising biomarkers for preeclampsia, which might regulate the pathogenesis of preeclampsia via metabolism pathways and immune microenvironment. Baicalein and luteolin could be potential therapeutics for preeclampsia.

Luteolin prevents TNF-α-induced NF-κB activation and ROS production in cultured human placental explants and endothelial cells

INTRODUCTION

Preeclampsia (PE) is a serious hypertensive pregnancy disorder and a leading cause of maternal and perinatal morbidity and mortality. Despite the prevalence and complications, there are no approved therapeutics to relieve PE symptoms. Inflammation, oxidative stress, and angiogenic imbalance have been shown to contribute to the PE pathophysiology, though there is a lack of understanding in how best to target these pathways in PE. We recently demonstrated that the bioflavonoid luteolin is a potent inhibitor of the anti-angiogenic and pro-hypertensive soluble fms-like tyrosine kinase 1 (sFlt-1), and here we aimed to determine if luteolin was also capable of reducing inflammation and oxidative stress pathways.

METHODS

Tumor necrosis factor (TNF)-α, which is upregulated in PE, was utilized to stimulate these pathways in human placental explants and endothelial cells. Endothelin-1 (ET-1) and interleukin (IL)-6 in the media from explants and cells were measured via ELISA, and NF-κB localization and reactive oxygen species were detected via fluorescence microscopy.

RESULTS

Pretreatment with luteolin demonstrated significant reductions in NF-κB activation, reactive oxygen species, superoxide, and IL-6 and ET-1 expression in endothelial cells. We also saw a significant reduction in phosphorylation of NF-κB in human placental explants.

DISCUSSION

These data demonstrate that luteolin inhibits pathways implicated in the development of PE and should be explored further for its potential as a PE therapeutic.