Protective effect of oleanolic acid on oxidized-low density lipoprotein induced endothelial cell apoptosis

Oleanolic acid improves the in vitro developmental competence of early porcine embryos by reducing oxidative stress and ameliorating mitochondrial function

OBJECTIVE

Oleanolic acid (OA) is a pentacyclic triterpenoid with antioxidant activity that can be an effective scavenger of free radicals in cells. This study was designed to investigate the effects of OA on porcine early embryo developmental competence in vitro and its possible mechanisms of action.

METHODS

In the present study, parthenogenetically activated porcine embryos were used as models to assess the effects of OA on the in vitro developmental capacity of early porcine embryos in vitro. Zygotic genome activation, mitochondrial function, oxidative stress, cell proliferation and apoptosis in early porcine embryos were examined after supplementing the culture medium with 5 μM OA.

RESULTS

The results showed that 5 μM OA supplementation not only significantly increased the blastocyst diameter in early embryos on day 6 but also increased the total cell number of blastocysts. Furthermore, OA supplementation increased the blastocyst proliferation rate and decreased blastocyst apoptosis. Moreover, OA supplementation significantly increased the proportion of embryos that developed to the 4-cell stage after 48 h of in vitro culture and upregulated the expression of genes associated with zygotic genome activation (DPPA2 and ZSCAN4). Notably, OA alleviated oxidative stress by reducing the intracellular levels of reactive oxygen species and increasing the intracellular levels of reduced glutathione at the 4-cell stage and increased the activities of superoxide dismutase and catalase. Concurrently, OA significantly increased the mitochondrial membrane potential and intracellular adenosine 5'-triphosphate content.

CONCLUSION

These results suggest that OA promotes the in vitro developmental competence of parthenogenetically activated porcine embryos by reducing oxidative stress and improving mitochondrial function during in vitro culture and that OA may contribute to the efficiency of in vitro embryo production.

The Effect and Mechanism of Oleanolic Acid in the Treatment of Metabolic Syndrome and Related Cardiovascular Diseases

Metabolic syndromes (MetS) and related cardiovascular diseases (CVDs) pose a serious threat to human health. MetS are metabolic disorders characterized by obesity, dyslipidemia, and hypertension, which increase the risk of CVDs' initiation and development. Although there are many availabile drugs for treating MetS and related CVDs, some side effects also occur. Considering the low-level side effects, many natural products have been tried to treat MetS and CVDs. A five-cyclic triterpenoid natural product, oleanolic acid (OA), has been reported to have many pharmacologic actions such as anti-hypertension, anti-hyperlipidemia, and liver protection. OA has specific advantages in the treatment of MetS and CVDs. OA achieves therapeutic effects through a variety of pathways, attracting great interest and playing a vital role in the treatment of MetS and CVDs. Consequently, in this article, we aim to review the pharmacological actions and potential mechanisms of OA in treating MetS and related CVDs.

miR-125a-3p aggravates ox-LDL-induced HUVEC injury through BAMBI

Atherosclerosis (AS) is a chronic inflammatory disease characterized by the formation of atherosclerotic plaque in the intima of arteries. Among the known regulators of atherosclerosis, microRNAs (miRNAs) have been reported to play critical roles in lipoprotein homeostasis and plaque formation. But the roles of microRNA-125a-3p (miR-125a-3p) in the pathogenesis of AS remain unknown. Human umbilical vein endothelial cells (HUVECs) were treated with oxidized low-density lipoprotein (ox-LDL) to construct the vascular injury model of AS pathogenesis in vitro. miR-125a-3p and BMP and activin membrane-bound inhibitor (BAMBI) expression levels in HUVECs were then measured by quantitative real-time polymerase chain reaction and western blot. The viability and apoptosis of HUVECs were analyzed by Cell Counting Kit-8 assay, TUNEL assay, and flow cytometry, respectively. The relationship between BAMBI 3'-untranslated region and miR-125a-3p was validated by dual luciferase reporter gene assay. miR-125a-3p expression was raised in HUVECs induced with ox-LDL. In HUVECs, miR-125a-3p enhanced the effects of ox-LDL treatment on repressing the viability and promoting the apoptosis of cells. Additionally, BAMBI was confirmed as a direct target of miR-125a-3p and BAMBI overexpression reversed the effects of miR-125a-3p on HUVECs. miR-125a-3p aggravates the dysfunction of HUVECs induced by ox-LDL via BAMBI, which implies that miR-125a-3p is involved in the pathogenesis of AS.

Suppression of apoptosis in vascular endothelial cell, the promising way for natural medicines to treat atherosclerosis

Atherosclerosis, a chronic multifactorial disease, is closely related to the development of cardiovascular diseases and is one of the predominant causes of death worldwide. Normal vascular endothelial cells play an important role in maintaining vascular homeostasis and inhibiting atherosclerosis by regulating vascular tension, preventing thrombosis and regulating inflammation. Currently, accumulating evidence has revealed that endothelial cell apoptosis is the first step of atherosclerosis. Excess apoptosis of endothelial cells induced by risk factors for atherosclerosis is a preliminary event in atherosclerosis development and might be a target for preventing and treating atherosclerosis. Interestingly, accumulating evidence shows that natural medicines have great potential to treat atherosclerosis by inhibiting endothelial cell apoptosis. Therefore, this paper reviewed current studies on the inhibitory effect of natural medicines on endothelial cell apoptosis and summarized the risk factors that may induce endothelial cell apoptosis, including oxidized low-density lipoprotein (ox-LDL), reactive oxygen species (ROS), angiotensin II (Ang II), tumor necrosis factor-α (TNF-α), homocysteine (Hcy) and lipopolysaccharide (LPS). We expect this review to highlight the importance of natural medicines, including extracts and monomers, in the treatment of atherosclerosis by inhibiting endothelial cell apoptosis and provide a foundation for the development of potential antiatherosclerotic drugs from natural medicines.

Prophylactic and therapeutic roles of oleanolic acid and its derivatives in several diseases

Oleanolic acid (OA) and its derivatives are widely found in diverse plants and are naturally effective pentacyclic triterpenoid compounds with broad prophylactic and therapeutic roles in various diseases such as ulcerative colitis, multiple sclerosis, metabolic disorders, diabetes, hepatitis and different cancers. This review assembles and presents the latest in vivo reports on the impacts of OA and OA derivatives from various plant sources and the biological mechanisms of OA activities. Thus, this review presents sufficient data proposing that OA and its derivatives are potential alternative and complementary therapies for the treatment and management of several diseases.

Atheroprotective effects and molecular targets of bioactive compounds from traditional Chinese medicine

Traditional Chinese medicine (TCM) has served the Chinese people since antiquity, and is playing an important role in today's healthcare. However, there has been controversy in the use of these traditional herbs due to unclear components and absence of scientific proof. As China plans to modernize traditional medicine, successful attempts to better understand the molecular mechanisms of TCM have been made by focusing on isolating active ingredients from these remedies. In this review, we critically examined the current evidence on atheroprotective effects of bioactive compounds from TCM using in vitro or in vivo models in the past two decades. A total of 47 active compounds were included in our review, which were introduced in the order of chemical structures, source, model, efficacy and mechanism. Notablely, this review highlighted the cellular and molecular mechanisms of these active compounds in prevention and treatment of atherosclerosis. Two compounds were also involved in double-blind, randomized, placebo-controlled clinical trials (RCTs). Besides, we introduced the legislations of the People's Republic of China ensuring quality and safety of products used in TCM. In summary, studies on bioactive compounds from TCM will provide a new approach for better management of atherosclerosis.

Cinnamaldehyde and allopurinol reduce fructose-induced cardiac inflammation and fibrosis by attenuating CD36-mediated TLR4/6-IRAK4/1 signaling to suppress NLRP3 inflammasome activation

Fructose consumption induces metabolic syndrome to increase cardiovascular disease risk. Cinnamaldehyde and allopurinol possess anti-oxidative and anti-inflammatory activity to relieve heart injury in metabolic syndrome. But the mechanisms of fructose-induced cardiac injury, and cardioprotective effects of cinnamaldehyde and allopurinol are not completely understood. In this study, fructose-fed rats displayed metabolic syndrome with elevated serum ox-LDL, cardiac oxidative stress, inflammation and fibrosis. Scavenger receptor CD36, Toll-like receptor 4 (TLR4), TLR6, IL-1R-associated kinase 4/1 (IRAK4/1), nucleotide-binding domain (NOD)-like receptor protein 3 (NLRP3) inflammasome, interleukin-1β, transforming growth factor-β (TGF-β), drosophila mothers against DPP homolog (Smad) 2/3 phosphorylation and Smad4 were increased in animal and H9c2 cell models. These pathological processes were further evaluated in ox-LDL or fructose-exposed H9c2 cells pretreated with ROS scavenger and CD36 specific inhibitor, or IRAK1/4 inhibitor, and transfected with CD36, NLRP3, or IRAK4/1 siRNA, demonstrating that NLPR3 inflammasome activation through CD36-mediated TLR4/6-IRAK4/1 signaling may promote cardiac inflammation and fibrosis. Cinnamaldehyde and allopurinol reduced cardiac oxidative stress to suppress NLPR3 inflammasome activation and TGF-β/Smads signaling by inhibiting CD36-mediated TLR4/6-IRAK4/1 signaling under fructose induction. These results suggest that the blockage of CD36-mediated TLR4/6-IRAK4/1 signaling to suppress NLRP3 inflammasome activation by cinnamaldehyde and allopurinol may protect against fructose-induced cardiac inflammation and fibrosis.