Procyanidin B2 mitigates endothelial endoplasmic reticulum stress through a PPARδ-Dependent mechanism

Comparisons of procyanidins with different low polymerization degrees on prevention of lipid metabolism in high-fat diet/streptozotocin-induced diabetic mice

Procyanidins, which are oligomerized flavan-3-ols with a polyphenolic structure, are bioactive substances that exhibit various biological effects. However, the relationship between the degree of polymerization (DP) of procyanidins and their bioactivities remains largely unknown. In this study, the preventive effects of procyanidins with different DP (EC, PB2 and PC1) on glucose improvement and liver lipid deposition were investigated using a high-fat diet/streptozotocin-induced diabetes mouse model. The results demonstrated that all the procyanidins with different DP effectively reduced fasting blood glucose and glucose/insulin tolerance, decreased the lipid profile (total cholesterol, triglyceride, and low-density lipoprotein cholesterol content) in serum and liver tissue as well as the liver oil red staining, indicating the improvement of glucose metabolism, insulin sensitivity and hepatic lipid deposition in diabetic mice. Furthermore, the procyanidins down-regulated expression of glucose regulated 78-kDa protein (GRP78) and C/EBP homologous protein (CHOP), indicating a regulation role of endoplasmic reticulum (ER) stress. The inhibition of ER stress by tauroursodeoxycholic acid (TUDCA) treatment abolished the effects of procyanidins with different DP in PA-induced HepG2 cells, confirming that procyanidins alleviate liver hyperlipidemia through the modulation of ER stress. Molecular docking results showed that EC and PB2 could better bind GRP78 and CHOP. Collectively, our study reveals that the structure of procyanidins, particularly DP, is not directly correlated with the improvement of blood glucose and lipid deposition, while highlighting the important role of ER stress in the bioactivities of procyanidins.

Research progress of procyanidins in repairing cartilage injury after anterior cruciate ligament tear

Anterior cruciate ligament (ACL) tear is a common sports-related injury, and cartilage injury always emerges as a serious complication following ACL tear, significantly impacting the physical and psychological well-being of affected individuals. Over the years, efforts have been directed toward finding strategies to repair cartilage injury after ACL tear. In recent times, procyanidins, known for their anti-inflammatory and antioxidant properties, have emerged as potential key players in addressing this concern. This article focuses on summarizing the research progress of procyanidins in repairing cartilage injury after ACL tear. It covers the roles, mechanisms, and clinical significance of procyanidins in repairing cartilage injury following ACL tear and explores the future prospects of procyanidins in this domain. This review provides novel insights and hope for the repair of cartilage injury following ACL tear.

Diabetes Mellitus to Accelerated Atherosclerosis: Shared Cellular and Molecular Mechanisms in Glucose and Lipid Metabolism

Diabetes is one of the critical independent risk factors for the progression of cardiovascular disease, and the underlying mechanism regarding this association remains poorly understood. Hence, it is urgent to decipher the fundamental pathophysiology and consequently provide new insights into the identification of innovative therapeutic targets for diabetic atherosclerosis. It is now appreciated that different cell types are heavily involved in the progress of diabetic atherosclerosis, including endothelial cells, macrophages, vascular smooth muscle cells, dependence on altered metabolic pathways, intracellular lipids, and high glucose. Additionally, extensive studies have elucidated that diabetes accelerates the odds of atherosclerosis with the explanation that these two chronic disorders share some common mechanisms, such as endothelial dysfunction and inflammation. In this review, we initially summarize the current research and proposed mechanisms and then highlight the role of these three cell types in diabetes-accelerated atherosclerosis and finally establish the mechanism pinpointing the relationship between diabetes and atherosclerosis.

Bioactive compounds from Actinidia arguta fruit as a new strategy to fight glioblastoma

In recent years, there has been a significant demand for natural products as a mean of disease prevention or as an alternative to conventional medications. The driving force for this change is the growing recognition of the abundant presence of valuable bioactive compounds in natural products. On recent years Actinia arguta fruit, also known as kiwiberry, has attracted a lot of attention from scientific community due to its richness in bioactive compounds, including phenolic compounds, organic acids, vitamins, carotenoids and fiber. These bioactive compounds contribute to the fruit's diverse outstanding biological activities such as antioxidant, anti-inflammatory, neuroprotective, immunomodulatory, and anti-cancer properties. Due to these properties, the fruit may have the potential to be used in the treatment/prevention of various types of cancer, including glioblastoma. Glioblastoma is the most aggressive form of brain cancer, displaying 90 % of recurrence rate within a span of 2 years. Despite the employment of an aggressive approach, the prognosis remains unfavorable, emphasizing the urgent requirement for the development of new effective treatments. The preclinical evidence suggests that kiwiberry has potential impact on glioblastoma by reducing the cancer self-renewal, modulating the signaling pathways involved in the regulation of the cell phenotype and metabolism, and influencing the consolidation of the tumor microenvironment. Even though, challenges such as the imprecise composition and concentration of bioactive compounds, and its low bioavailability after oral administration may be drawbacks to the development of kiwiberry-based treatments, being urgent to ensure the safety and efficacy of kiwiberry for the prevention and treatment of glioblastoma. This review aims to highlight the potential impact of A. arguta bioactive compounds on glioblastoma, providing novel insights into their applicability as complementary or alternative therapies.

The role and mechanisms of microvascular damage in the ischemic myocardium

Following myocardial ischemic injury, the most effective clinical intervention is timely restoration of blood perfusion to ischemic but viable myocardium to reduce irreversible myocardial necrosis, limit infarct size, and prevent cardiac insufficiency. However, reperfusion itself may exacerbate cell death and myocardial injury, a process commonly referred to as ischemia/reperfusion (I/R) injury, which primarily involves cardiomyocytes and cardiac microvascular endothelial cells (CMECs) and is characterized by myocardial stunning, microvascular damage (MVD), reperfusion arrhythmia, and lethal reperfusion injury. MVD caused by I/R has been a neglected problem compared to myocardial injury. Clinically, the incidence of microvascular angina and/or no-reflow due to ineffective coronary perfusion accounts for 5-50% in patients after acute revascularization. MVD limiting drug diffusion into injured myocardium, is strongly associated with the development of heart failure. CMECs account for > 60% of the cardiac cellular components, and their role in myocardial I/R injury cannot be ignored. There are many studies on microvascular obstruction, but few studies on microvascular leakage, which may be mainly due to the lack of corresponding detection methods. In this review, we summarize the clinical manifestations, related mechanisms of MVD during myocardial I/R, laboratory and clinical examination means, as well as the research progress on potential therapies for MVD in recent years. Better understanding the characteristics and risk factors of MVD in patients after hemodynamic reconstruction is of great significance for managing MVD, preventing heart failure and improving patient prognosis.

Effects of grape seed-derived proanthocyanidin B2 pretreatment on oxidative stress, endoplasmic reticulum stress and apoptosis of renal tubular epithelial cells in renal ischemia-reperfusion injury model of mice

PURPOSE

To investigate the effect of grape seed-derived proanthocyanidin B2 (GSPB2) pretreatment on acute renal ischemia-reperfusion injury model of mice.

METHODS

50 mice were divided into 5 groups: Sham group: mice were treated with right nephrectomy. GSPB2 group: GSPB2 was injected intraperitoneally 45 min before right nephrectomy. IRI group: right kidney was resected and the left renal arteriovenous vessel was blocked for 45 min. GSPB2 + IRI group: GSPB2 was intraperitoneally injected 45 min before IRI established. GSPB2 + BRU + IRI group: GSPB2 and brusatol (BRU) were injected intraperitoneally 45 min before IRI established. Creatinine and urea nitrogen of mice were detected, and the kidney morphology and pathological changes of each group were detected by HE staining, PAS staining and transmission electron microscopy. Expressions of Nrf2, HO-1, GRP78, CHOP, and cleaved-caspase3 were detected by immunofluorescence staining and western blotting.

RESULTS

Morphology and mitochondrial damages of kidney in GSPB2 + IRI group were significantly alleviated than those in IRI group. Expression levels of Nrf2 and HO-1 were significantly higher in GSPB2 + IRI group than those in IRI group. Expression levels of GRP78, CHOP and cleaved-caspase3 were significantly lower in GSPB2 + IRI group than those in IRI group. However, compared to GSPB2 + IRI group, protective effects of GSPB2 pretreatment were weakened in GSPB2 + BRU + IRI group.

CONCLUSIONS

GSPB2 pretreatment could alleviate oxidative stress damage and reduce apoptosis of renal tubular epithelial cells, which might be related to activating the antioxidant system, up-regulating the expression of Nrf2 and HO-1, inhibiting the expressions of GRP78, CHOP and cleaved-caspase3. However, the protective effect could be reversed by brusatol.

Procyanidin B2: A promising multi-functional food-derived pigment for human diseases

Natural edible pigments play a paramount part in the food industry. Procyanidin B2 (PB2), one of the most representative naturally occurring edible pigments, is usually isolated from the seeds, fruits, and leaves of lots of common plants, such as grapes, Hawthorn, black soybean, as well as blueberry, and functions as a food additive in daily life. Notably, PB2 has numerous bioactivities and possesses the potential to treat/prevent a wide range of human diseases, such as diabetes mellitus, diabetic complications, atherosclerosis, and non-alcoholic fatty liver disease, and the underlying mechanisms were partially elucidated, including mediating signaling pathways like NF-κB, MAPK, PI3K/Akt, apoptotic axis, and Nrf-2/HO-1. This paper presents a review of the natural sources, bioactivities, and the therapeutic/preventive potential of PB2 and the possible mechanisms, with the aim of promoting the development of PB2 as a functional food and providing references for its clinical application in the treatment of diseases.

Procyanidins: A promising anti-diabetic agent with potential benefits on glucose metabolism and diabetes complications

Diabetes mellitus (DM) is a complex disease with alarming worldwide health implications and high mortality rates, largely due to its complications such as cardiovascular disease, nephropathy, neuropathy, and retinopathy. Recent research has shown that procyanidins (PC), a type of flavonoid, have strong antioxidant and free radical elimination effects, and may be useful in improving glucose metabolism, enhancing pancreatic islet cell activity, and decreasing the prevalence of DM complications. This review article presents a systematic search for peer-reviewed articles on the use of PC in the treatment of DM, without any language restrictions. The article also discusses the potential for PC to sensitise DM medications and improve their efficacy. Recent in vivo and in vitro studies have demonstrated promising results in improving the biological activity and bioavailability of PC for the treatment of DM. The article concludes by highlighting the potential for novel materials and targeted drug delivery methods to enhance the pharmacokinetics and bioactivity of PC, leading to the creation of safer and more effective anti-DM medications in the future.

Endoplasmic reticulum stress: a novel targeted approach to repair bone defects by regulating osteogenesis and angiogenesis

Bone regeneration therapy is clinically important, and targeted regulation of endoplasmic reticulum (ER) stress is important in regenerative medicine. The processing of proteins in the ER controls cell fate. The accumulation of misfolded and unfolded proteins occurs in pathological states, triggering ER stress. ER stress restores homeostasis through three main mechanisms, including protein kinase-R-like ER kinase (PERK), inositol-requiring enzyme 1ɑ (IRE1ɑ) and activating transcription factor 6 (ATF6), collectively known as the unfolded protein response (UPR). However, the UPR has both adaptive and apoptotic effects. Modulation of ER stress has therapeutic potential for numerous diseases. Repair of bone defects involves both angiogenesis and bone regeneration. Here, we review the effects of ER stress on osteogenesis and angiogenesis, with emphasis on ER stress under high glucose (HG) and inflammatory conditions, and the use of ER stress inducers or inhibitors to regulate osteogenesis and angiogenesis. In addition, we highlight the ability for exosomes to regulate ER stress. Recent advances in the regulation of ER stress mediated osteogenesis and angiogenesis suggest novel therapeutic options for bone defects.

Modulation of NRF2/KEAP1 Signaling in Preeclampsia

Placentation is a key and tightly regulated process that ensures the normal development of the placenta and fetal growth. Preeclampsia (PE) is a hypertensive pregnancy-related disorder involving about 5-8% of all pregnancies and clinically characterized by de novo maternal hypertension and proteinuria. In addition, PE pregnancies are also characterized by increased oxidative stress and inflammation. The NRF2/KEAP1 signaling pathway plays an important role in protecting cells against oxidative damage due to increased reactive oxygen species (ROS) levels. ROS activate NRF2, allowing its binding to the antioxidant response element (ARE) region present in the promoter of several antioxidant genes such as heme oxygenase, catalase, glutathione peroxidase and superoxide dismutase that neutralize ROS, protecting cells against oxidative stress damages. In this review, we analyze the current literature regarding the role of the NRF2/KEAP1 pathway in preeclamptic pregnancies, discussing the main cellular modulators of this pathway. Moreover, we also discuss the main natural and synthetic compounds that can regulate this pathway in in vivo and in vitro models.

Glucagon-like peptide-1 receptor regulates receptor of advanced glycation end products in high glucose-treated rat mesangial cells

BACKGROUND

Hyperglycemia-induced advanced glycation end products (AGEs) and receptor for AGEs (RAGEs) play major roles in diabetic nephropathy progression. In previous study, both glucagon-like peptide-1 (GLP-1) and peroxisome proliferator-activated receptors delta (PPARδ) agonists were shown to have anti-inflammatory effect on AGE-treated rat mesangial cells (RMCs). The interaction among PPARδ agonists, GLP-1, and AGE-RAGE axis is, however, still unclear.

METHODS

In this study, the individual and synergic effect of PPARδ agonist (L-165 041) and siRNA of GLP-1 receptor (GLP-1R) on the expression of GLP-1, GLP-1R, RAGE, and cell viability in AGE-treated RMCs were investigated.

RESULTS

L-165 041 enhanced GLP-1R mRNA and protein expression only in the presence of AGE. The expression of RAGE mRNA and protein was enhanced by AGE, attenuated by L-165 041, and siRNA of GLP-1R reversed L-165 041-induced inhibition. Cell viability was also inhibited by AGE. L-165 041 attenuated AGE-induced inhibition and siRNA GLP-1R diminished L-165 041 effect.

CONCLUSION

PPARδ agonists increase GLP-1R expression on RMC in the presence of AGE. PPARδ agonists also attenuate AGE-induced upregulated RAGE expression and downregulated cell viability. The effect of PPARδ agonists needs the cooperation of GLP-1R activation.

Selected Seeds as Sources of Bioactive Compounds with Diverse Biological Activities

Seeds contain a variety of phytochemicals that exhibit a wide range of biological activities. Plant-derived compounds are often investigated for their antioxidant, anti-inflammatory, immunomodulatory, hypoglycemic, anti-hypercholesterolemic, anti-hypertensive, anti-platelet, anti-apoptotic, anti-nociceptive, antibacterial, antiviral, anticancer, hepatoprotective, or neuroprotective properties. In this review, we have described the chemical content and biological activity of seeds from eight selected plant species-blackberry (Rubus fruticosus L.), black raspberry (Rubus coreanus Miq.), grape (Vitis vinifera L.), Moringa oleifera Lam., sea buckthorn (Hippophae rhamnoides L.), Gac (Momordica cochinchinensis Sprenger), hemp (Cannabis sativa L.), and sacha inchi (Plukenetia volubilis L). This review is based on studies identified in electronic databases, including PubMed, ScienceDirect, and SCOPUS. Numerous preclinical, and some clinical studies have found that extracts, fractions, oil, flour, proteins, polysaccharides, or purified chemical compounds isolated from the seeds of these plants display promising, health-promoting effects, and could be utilized in drug development, or to make nutraceuticals and functional foods. Despite that, many of these properties have been studied only in vitro, and it's unsure if their effects would be relevant in vivo as well, so there is a need for more animal studies and clinical trials that would help determine if they could be applied in disease prevention or treatment.

The Impact of Oxidative Stress and AKT Pathway on Cancer Cell Functions and Its Application to Natural Products

Oxidative stress and AKT serine-threonine kinase (AKT) are responsible for regulating several cell functions of cancer cells. Several natural products modulate both oxidative stress and AKT for anticancer effects. However, the impact of natural product-modulating oxidative stress and AKT on cell functions lacks systemic understanding. Notably, the contribution of regulating cell functions by AKT downstream effectors is not yet well integrated. This review explores the role of oxidative stress and AKT pathway (AKT/AKT effectors) on ten cell functions, including apoptosis, autophagy, endoplasmic reticulum stress, mitochondrial morphogenesis, ferroptosis, necroptosis, DNA damage response, senescence, migration, and cell-cycle progression. The impact of oxidative stress and AKT are connected to these cell functions through cell function mediators. Moreover, the AKT effectors related to cell functions are integrated. Based on this rationale, natural products with the modulating abilities for oxidative stress and AKT pathway exhibit the potential to regulate these cell functions, but some were rarely reported, particularly for AKT effectors. This review sheds light on understanding the roles of oxidative stress and AKT pathway in regulating cell functions, providing future directions for natural products in cancer treatment.

Paeonol protects against doxorubicin-induced cardiotoxicity by promoting Mfn2-mediated mitochondrial fusion through activating the PKCε-Stat3 pathway

INTRODUCTION

The anti-cancer medication doxorubicin (Dox) is largely restricted in clinical usage due to its significant cardiotoxicity. The only medication approved by the FDA for Dox-induced cardiotoxicity is dexrazoxane, while it may reduce the sensitivity of cancer cells to chemotherapy and is restricted for use. There is an urgent need for the development of safe and effective medicines to alleviate Dox-induced cardiotoxicity.

OBJECTIVES

The objective of this study was to determine whether Paeonol (Pae) has the ability to protect against Dox-induced cardiotoxicity and if so, what are the underlying mechanisms involved.

METHODS

Sprague-Dawley rats and primary cardiomyocytes were used to create Dox-induced cardiotoxicity models. Pae's effects on myocardial damage, mitochondrial function, mitochondrial dynamics and signaling pathways were studied using a range of experimental methods.

RESULTS

Pae enhanced Mfn2-mediated mitochondrial fusion, restored mitochondrial function and cardiac performance both in vivo and in vitro under the Dox conditions. The protective properties of Pae were blunted when Mfn2 was knocked down or knocked out in Dox-induced cardiomyocytes and hearts respectively. Mechanistically, Pae promoted Mfn2-mediated mitochondria fusion by activating the transcription factor Stat3, which bound to the Mfn2 promoter in a direct manner and up-regulated its transcriptional expression. Furthermore, molecular docking, surface plasmon resonance and co-immunoprecipitation studies showed that Pae's direct target was PKCε, which interacted with Stat3 and enabled its phosphorylation and activation. Pae-induced Stat3 phosphorylation and Mfn2-mediated mitochondrial fusion were inhibited when PKCε was knocked down. Furthermore, Pae did not interfere with Dox's antitumor efficacy in several tumor cells.

CONCLUSION

Pae protects the heart against Dox-induced damage by stimulating mitochondrial fusion via the PKCε-Stat3-Mfn2 pathway, indicating that Pae might be a promising therapeutic therapy for Dox-induced cardiotoxicity while maintaining Dox's anticancer activity.

Mitochondrial PKM2 deacetylation by procyanidin B2-induced SIRT3 upregulation alleviates lung ischemia/reperfusion injury

Apoptosis is a critical event in the pathogenesis of lung ischemia/reperfusion (I/R) injury. Sirtuin 3 (SIRT3), an important deacetylase predominantly localized in mitochondria, regulates diverse physiological processes, including apoptosis. However, the detailed mechanisms by which SIRT3 regulates lung I/R injury remain unclear. Many polyphenols strongly regulate the sirtuin family. In this study, we found that a polyphenol compound, procyanidin B2 (PCB2), activated SIRT3 in mouse lungs. Due to this effect, PCB2 administration attenuated histological lesions, relieved pulmonary dysfunction, and improved the survival rate of the murine model of lung I/R injury. Additionally, this treatment inhibited hypoxia/reoxygenation (H/R)-induced A549 cell apoptosis and rescued Bcl-2 expression. Using Sirt3-knockout mice and specific SIRT3 knockdown in vitro, we further found that SIRT3 strongly protects against lung I/R injury. Sirt3 deficiency or enzymatic inactivation substantially aggravated lung I/R-induced pulmonary lesions, promoted apoptosis, and abolished PCB2-mediated protection. Mitochondrial pyruvate kinase M2 (PKM2) inhibits apoptosis by stabilizing Bcl-2. Here, we found that PKM2 accumulates and is hyperacetylated in mitochondria upon lung I/R injury. By screening the potential sites of PKM2 acetylation, we found that SIRT3 deacetylates the K433 residue of PKM2 in A549 cells. Transfection with a deacetylated mimic plasmid of PKM2 noticeably reduced apoptosis, while acetylated mimic transfection abolished the protective effect of PKM2. Furthermore, PKM2 knockdown or inhibition in vivo significantly abrogated the antiapoptotic effects of SIRT3 upregulation. Collectively, this study provides the first evidence that the SIRT3/PKM2 pathway is a protective target for the suppression of apoptosis in lung I/R injury. Moreover, this study identifies K433 deacetylation of PKM2 as a novel modification that regulates its anti-apoptotic activity. In addition, PCB2-mediated modulation of the SIRT3/PKM2 pathway may significantly protect against lung I/R injury, suggesting a novel prophylactic strategy for lung I/R injury.

Procyanidins and Their Therapeutic Potential against Oral Diseases

Procyanidins, as a kind of dietary flavonoid, have excellent pharmacological properties, such as antioxidant, antibacterial, anti-inflammatory and anti-tumor properties, and so they can be used to treat various diseases, including Alzheimer’s disease, diabetes, rheumatoid arthritis, tumors, and obesity. Given the low bioavailability of procyanidins, great efforts have been made in drug delivery systems to address their limited use. Nowadays, the heavy burden of oral diseases such as dental caries, periodontitis, endodontic infections, etc., and their consequences on the patients’ quality of life indicate a strong need for developing effective therapies. Recent years, plenty of efforts are being made to develop more effective treatments. Therefore, this review summarized the latest researches on versatile effects and enhanced bioavailability of procyanidins resulting from innovative drug delivery systems, particularly focused on its potential against oral diseases.

Targeting endothelial dysfunction and inflammation

Vascular endothelium maintains vascular homeostasis through liberating a spectrum of vasoactive molecules, both protective and harmful regulators of vascular tone, structural remodeling, inflammation and atherogenesis. An intricate balance between endothelium-derived relaxing factors (nitric oxide, prostacyclin and endothelium-derived hyperpolarizing factor) and endothelium-derived contracting factors (superoxide anion, endothelin-1 and constrictive prostaglandins) tightly regulates vascular function. Disruption of such balance signifies endothelial dysfunction, a critical contributor in aging and chronic cardiometabolic disorders, such as obesity, diabetes, hypertension, dyslipidemia and atherosclerotic vascular diseases. Among many proposed cellular and molecular mechanisms causing endothelial dysfunction, oxidative stress and inflammation are often the pivotal players and they are naturally considered as useful targets for intervention in patients with cardiovascular and metabolic diseases. In this article, we provide a recent update on the therapeutic values of pharmacological agents, such as cyclooxygenase-2 inhibitors, renin-angiotensin-system inhibitors, bone morphogenic protein 4 inhibitors, peroxisome proliferator-activated receptor δ agonists, and glucagon-like peptide 1-elevating drugs, and the physiological factors, particularly hemodynamic forces, that improve endothelial function by targeting endothelial oxidative stress and inflammation.

Procyanidin B2 Protects Aged Oocytes Against Meiotic Defects Through Cortical Tension Modulation

Defects in meiotic process are the main factors responsible for the decreased developmental competence in aged oocytes. Our recent research indicated that natural antioxidant procyanidin B2 (PCB2) promoted maturation progress in oocytes from diabetic mice. However, the effect of PCB2 on aging-induced chromosome abnormalities and the underlying mechanism have not been explored. Here, we found that PCB2 recovered aging-caused developmental arrest during meiotic maturation, germinal vesicle breakdown (GVBD) rate was significantly higher in aged oocytes treated with PCB2 (P < 0.05). Furthermore, we discovered that cortical mechanics were altered during aging process, cortical tension-related proteins were aberrantly expressed in aged oocytes (P < 0.001). PCB2 supplementation efficaciously antagonized aging-induced decreased cortical tension (P < 0.001). Moreover, PCB2 restored spindle morphology (P < 0.01), maintained proper chromosome alignment (P < 0.05), and dramatically reduced reactive oxygen species (ROS) level (P < 0.05) in aged oocytes. Collectively, our results reveal that PCB2 supplementation is a feasible approach to protect oocytes from reproductive aging, contributing to the improvement of oocytes quality.

Procyanidin B2 ameliorates endothelial dysfunction and impaired angiogenesis via the Nrf2/PPARγ/sFlt-1 axis in preeclampsia

Preeclampsia is a severe complication of pregnancy characterized by variable degrees of placental malperfusion. A growing body of evidence indicates that soluble endoglin and soluble fms-like tyrosine kinase-1 (sFlt-1) play important pathophysiological roles in preeclampsia, causing endothelial dysfunction, hypertension, and multiorgan injury. A drug that is safe in pregnancy and inhibits placental sFlt-1 and soluble endoglin secretion would be an attractive treatment strategy for preeclampsia. Procyanidin B2, a bioactive food compound, has been reported to exert multiple beneficial functions. Placental explant cultures in vitro are useful for studying tissue functions including release of secretory components, pharmacology, toxicology, and disease processes. The reduced uterine perfusion pressure (RUPP) rat model has been widely used as a model of preeclampsia. We aimed to investigate the effect of procyanidin B2 on preeclampsia via using placental explant cultures and RUPP rat model. In this study, we demonstrated that procyanidin B2 reduced soluble endoglin and sFlt-1 secretion from human umbilical vein endothelial cells (HUVECs), primary trophoblasts, and placental explants from preeclamptic pregnancies. Moreover, procyanidin B2 alleviated endothelial dysfunction and impaired angiogenesis induced by sFlt-1, including increasing the migration, invasion and angiogenesis of endothelial cells and decreasing the expression of vascular cell adhesion molecule-1 (VCAM-1) and leukocyte adhesion on HUVECs. In addition, procyanidin B2 promoted nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation and induced peroxisome proliferator-activated receptor γ (PPARγ) expression in primary placental tissues and endothelial cells. Importantly, Nrf2 specifically binds to the PPARγ promoter region (-1227/-1217) and enhances its transcriptional activity. Procyanidin B2 inhibits sFlt-1 secretion via the Nrf2/PPARγ axis. In the RUPP rat model of preeclampsia, procyanidin B2 attenuated RUPP-induced maternal angiogenic imbalance, hypertension and improved placental and fetal weight. Taken together, our results demonstrate that procyanidin B2 inhibits sFlt-1 secretion and ameliorates endothelial dysfunction and impaired angiogenesis via the Nrf2/PPARγ axis in preeclampsia. Procyanidin B2 may be a novel therapeutic agent for treatment of preeclampsia.

The Cell Protective Effect of Adenine on Hypoxia-Reoxygenation Injury through PPAR Delta Activation

Ischemia followed by blood supply reperfusion in cardiomyocytes leads to an overproduction of free radicals and a rapid decrease of adenosine triphosphate concentration. The cardioprotective effect of a potential drug, adenine, was evaluated using H9c2 rat cardiomyoblasts. After hypoxia–reoxygenation (HR) treatment consisting of hypoxia for 21 h followed by reoxygenation for 6 h, it was revealed that pretreatment with 200 µM adenine for 2 h effectively prevented HR-induced cell death. Adenine also significantly decreased the production of reactive oxygen species and reduced cell apoptosis after HR injury. The antioxidant effect of adenine was also revealed in this study. Adenine pretreatment significantly reduced the expression of activating transcription factor 4 (ATF4) and glucose-regulated protein 78 (GRP78) proteins, and protein disulfide isomerase induced a protective effect on mitochondria after HR stimulation. Intracellular adenosine monophosphate-activated protein kinase, peroxisome proliferator-activated receptor delta (PPARδ), and perilipin levels were increased by adenine after HR stimulation. Adenine had a protective effect in HR-damaged H9c2 cells. It may be used in multiple preventive medicines in the future.

Omnifarious fruit polyphenols: an omnipotent strategy to prevent and intervene diabetes and related complication?

Diabetes mellitus is a metabolic syndrome which cannot be cured. Recently, considerable interest has been focused on food ingredients to prevent and intervene in complications of diabetes. Polyphenolic compounds are one of the bioactive phytochemical constituents with various biological activities, which have drawn increasing interest in human health. Fruits are part of the polyphenol sources in daily food consumption. Fruit-derived polyphenols possess the anti-diabetic activity that has already been proved either from in vitro studies or in vivo studies. The mechanisms of fruit polyphenols in treating diabetes and related complications are under discussion. This is a comprehensive review on polyphenols from the edible parts of fruits, including those from citrus, berries, apples, cherries, mangoes, mangosteens, pomegranates, and other fruits regarding their potential benefits in preventing and treating diabetes mellitus. The signal pathways of characteristic polyphenols derived from fruits in reducing high blood glucose and intervening hyperglycemia-induced diabetic complications were summarized.

ER Stress in Cardiometabolic Diseases: From Molecular Mechanisms to Therapeutics

The endoplasmic reticulum (ER) hosts linear polypeptides and fosters natural folding of proteins through ER-residing chaperones and enzymes. Failure of the ER to align and compose proper protein architecture leads to accumulation of misfolded/unfolded proteins in the ER lumen, which disturbs ER homeostasis to provoke ER stress. Presence of ER stress initiates the cytoprotective unfolded protein response (UPR) to restore ER homeostasis or instigates a rather maladaptive UPR to promote cell death. Although a wide array of cellular processes such as persistent autophagy, dysregulated mitophagy, and secretion of proinflammatory cytokines may contribute to the onset and progression of cardiometabolic diseases, it is well perceived that ER stress also evokes the onset and development of cardiometabolic diseases, particularly cardiovascular diseases (CVDs), diabetes mellitus, obesity, and chronic kidney disease (CKD). Meanwhile, these pathological conditions further aggravate ER stress, creating a rather vicious cycle. Here in this review, we aimed at summarizing and updating the available information on ER stress in CVDs, diabetes mellitus, obesity, and CKD, hoping to offer novel insights for the management of these cardiometabolic comorbidities through regulation of ER stress.

The Protective Effect of Quercetin on Endothelial Cells Injured by Hypoxia and Reoxygenation

Background: Cerebral small vessel disease (CSVD) is a group of clinical syndromes covering all pathological processes of small vessels in the brain, which can cause stroke and serious dementia. However, as the pathogenesis of CSVD is not clear, so the treatment is limited. Endothelial cell dysfunction is earlier than clinical symptoms, such as hypertension and leukosis. Therefore, the treatment of endothelial cells is expected to be a new breakthrough. Quercetin, a flavonoid present in a variety of plants, has the function of anti-inflammation and anti-oxidation. This study aimed to investigate the protective effect of quercetin on endothelial cell injury and provide a basic theory for subsequent application in the clinic. Methods: Human brain microvascular endothelial cells (HBMECs) were cultured in vitro, and the injury model of endothelial cells was established by hypoxia and reoxygenation (H/R). The protective effects of quercetin on HBMECs were studied from the perspectives of cell viability, cell migration, angiogenesis and apoptosis. In order to further study the mechanism of quercetin, oxidative stress and endoplasmic reticulum stress were analyzed. What's more, blood-brain barrier (BBB) integrity was also studied. Results: Quercetin can promote the viability, migration and angiogenesis of HBMECs, and inhibit the apoptosis. In addition, quercetin can also activate Keap1/Nrf2 signaling pathway, reduce ATF6/GRP78 protein expression. Further study showed that quercetin could increase the expression of Claudin-5 and Zonula occludens-1. Conclusions: Our experiments show that quercetin can protect HBMECs from H/R, which contains promoting cell proliferation, cell migration and angiogenesis, reducing mitochondrial membrane potential damage and inhibiting cell apoptosis. This may be related to its antioxidation and inhibition of endoplasmic reticulum stress. At the same time, quercetin can increase the level of BBB connexin, suggesting that quercetin can maintain BBB integrity.

Bevacizumab-Induced Mitochondrial Dysfunction, Endoplasmic Reticulum Stress, and ERK Inactivation Contribute to Cardiotoxicity

The molecular mechanisms underlying the cardiotoxicity associated with bevacizumab, a first-line immunotherapeutic agent used to treat lung cancer, are not fully understood. Here, we examined intracellular signal transduction in cardiomyocytes after exposure to different doses of bevacizumab in vitro. Our results demonstrated that bevacizumab significantly and dose-dependently reduces cardiomyocyte viability and increases cell apoptosis. Bevacizumab treatment also led to mitochondrial dysfunction in cardiomyocytes, as evidenced by the decreased ATP production, increased ROS production, attenuated antioxidative enzyme levels, and reduced respiratory complex function. In addition, bevacizumab induced intracellular calcium overload, ER stress, and caspase-12 activation. Finally, bevacizumab treatment inhibited the ERK signaling pathway, which, in turn, significantly reduced cardiomyocyte viability and contributed to mitochondrial dysfunction. Together, our results demonstrate that bevacizumab-mediated cardiotoxicity is associated with mitochondrial dysfunction, ER stress, and ERK pathway inactivation. These findings may provide potential treatment targets to attenuate myocardial injury during lung cancer immunotherapy.

Melatonin Attenuates ox-LDL-Induced Endothelial Dysfunction by Reducing ER Stress and Inhibiting JNK/Mff Signaling

Endothelial dysfunction, which is characterized by damage to the endoplasmic reticulum (ER) and mitochondria, is involved in a variety of cardiovascular disorders. Here, we explored whether mitochondrial damage and ER stress are associated with endothelial dysfunction. We also examined whether and how melatonin protects against oxidized low-density lipoprotein- (ox-LDL-) induced damage in endothelial cells. We found that CHOP, GRP78, and PERK expressions, which are indicative of ER stress, increased significantly in response to ox-LDL treatment. ox-LDL also induced mitochondrial dysfunction as evidenced by decreased mitochondrial membrane potential, increased mitochondrial ROS levels, and downregulation of mitochondrial protective factors. In addition, ox-LDL inhibited antioxidative processes, as evidenced by decreased antioxidative enzyme activity and reduced Nrf2/HO-1 expression. Melatonin clearly reduced ER stress and promoted mitochondrial function and antioxidative processes in the presence of ox-LDL. Molecular investigation revealed that ox-LDL activated the JNK/Mff signaling pathway, and melatonin blocked this effect. These results demonstrate that ox-LDL induces ER stress and mitochondrial dysfunction and activates the JNK/Mff signaling pathway, thereby contributing to endothelial dysfunction. Moreover, melatonin inhibited JNK/Mff signaling and sustained ER homeostasis and mitochondrial function, thereby protecting endothelial cells against ox-LDL-induced damage.