Celastrol prevents atherosclerosis via inhibiting LOX-1 and oxidative stress

Celastrol enhances the viability of random-pattern skin flaps by regulating autophagy through the AMPK-mTOR-TFEB axis

In reconstructive and plastic surgery, random-pattern skin flaps (RPSF) are often used to correct defects. However, their clinical usefulness is limited due to their susceptibility to necrosis, especially on the distal side of the RPSF. This study validates the protective effect of celastrol (CEL) on flap viability and explores in terms of underlying mechanisms of action. The viability of different groups of RPSF was evaluated by survival zone analysis, laser doppler blood flow, and histological analysis. The effects of CEL on flap angiogenesis, apoptosis, oxidative stress, and autophagy were evaluated by Western blot, immunohistochemistry, and immunofluorescence assays. Finally, its mechanistic aspects were explored by autophagy inhibitor and Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) inhibitor. On the seventh day after surgery, the survival area size, blood supply, and microvessel count of RPSF were augmented following the administration of CEL. Additionally, CEL stimulated angiogenesis, suppressed apoptosis, and lowered oxidative stress levels immediately after elevated autophagy in ischemic regions; These effects can be reversed using the autophagy inhibitor chloroquine (CQ). Specifically, CQ has been observed to counteract the protective impact of CEL on the RPSF. Moreover, it has also been discovered that CEL triggers the AMPK-mTOR-TFEB axis activation in the area affected by ischemia. In CEL-treated skin flaps, AMPK inhibitors were demonstrated to suppress the AMPK-mTOR-TFEB axis and reduce autophagy levels. This investigation suggests that CEL benefits the survival of RPSF by augmenting angiogenesis and impeding oxidative stress and apoptosis. The results are credited to increased autophagy, made possible by the AMPK-mTOR-TFEB axis activation.

Celastrol inhibits oligodendrocyte and neuron ferroptosis to promote spinal cord injury recovery

BACKGROUND

Spinal cord injury (SCI) is a traumatic injury to the central nervous system and can cause lipid peroxidation in the spinal cord. Ferroptosis, an iron-dependent programmed cell death, plays a key role in the pathophysiology progression of SCI. Celastrol, a widely used antioxidant drug, has potential therapeutic value for nervous system.

PURPOSE

To investigate whether celastrol can be a reliable candidate for ferroptosis inhibitor and the molecular mechanism of celastrol in repairing SCI by inhibiting ferroptosis.

METHODS

First, a rat SCI model was constructed, and the recovery of motor function was observed after treatment with celastrol. The regulatory effect of celastrol on ferroptosis pathway Nrf2-xCT-GPX4 was detected by Western blot and immunofluorescence. Finally, the ferroptosis model of neurons and oligodendrocytes was constructed in vitro to further verify the mechanism of inhibiting ferroptosis by celastrol.

RESULTS

Our results demonstrated that celastrol promoted the recovery of spinal cord tissue and motor function in SCI rats. Further in vitro and in vivo studies showed that celastrol significantly inhibited ferroptosis in neurons and oligodendrocytes and reduced the accumulation of ROS. Finally, we found that celastrol could inhibit ferroptosis by up-regulating the Nrf2-xCT-GPX4 axis to repair SCI.

CONCLUSION

Celastrol effectively inhibits ferroptosis after SCI by upregulating the Nrf2-xCT-GPX4 axis, reducing the production of lipid ROS, protecting the survival of neurons and oligodendrocytes, and improving the functional recovery.

Celastrol alleviates diabetic vascular injury via Keap1/Nrf2-mediated anti-inflammation

Introduction: Celastrol (Cel) is a widely used main component of Chinese herbal medicine with strong anti-inflammatory, antiviral and antitumor activities. In the present study, we aimed to elucidate the cellular molecular protective mechanism of Cel against diabetes-induced inflammation and endothelial dysfunction. Methods: Type 2 diabetes (T2DM) was induced by db/db mice, and osmotic pumps containing Cel (100 μg/kg/day) were implanted intraperitoneally and were calibrated to release the drug for 28 days. In addition, human umbilical vein endothelial cells (HUVECs) were cultured in normal or high glucose and palmitic acid-containing (HG + PA) media in the presence or absence of Cel for 48 h. Results: Cel significantly ameliorated the hyperglycemia-induced abnormalities in nuclear factor (erythroid-derived 2)-like protein 2 (Nrf2) pathway activity and alleviated HG + PA-induced oxidative damage. However, the protective effect of Cel was almost completely abolished in HUVECs transfected with short hairpin (sh)RNA targeting Nrf2, but not by nonsense shRNA. Furthermore, HG + PA reduced the phosphorylation of AMP-activated protein kinase (AMPK), the autophagic degradation of p62/Kelch-like ECH-associated protein 1 (Keap1), and the nuclear localization of Nrf2. However, these catabolic pathways were inhibited by Cel treatment in HUVECs. In addition, compound C (AMPK inhibitors) and AAV9-sh-Nrf2 reduced Cel-induced Nrf2 activation and angiogenesis in db/db mice. Discussion: Taking these findings together, the endothelial protective effect of Cel in the presence of HG + PA may be at least in part attributed to its effects to reduce reactive oxygen species (ROS) and inflammation through p62/Keap1-mediated Nrf2 activation.

Withaferin A and Celastrol Overwhelm Proteostasis

Withaferin A (WA) and celastrol (CEL) are major bioactive components of plants that have been widely employed in traditional medicine. The pleiotropic activities of plant preparations and the isolated compounds in vitro and in vivo have been documented in hundreds of studies. Both WA and CEL were shown to have anticancer activity. Although WA and CEL belong to different chemical classes, our synthesis of the available information suggests that the compounds share basic mechanisms of action. Both WA and CEL bind covalently to numerous proteins, causing the partial unfolding of some of these proteins and of many bystander proteins. The resulting proteotoxic stress, when excessive, leads to cell death. Both WA and CEL trigger the activation of the unfolded protein response (UPR) which, if the proteotoxic stress persists, results in apoptosis mediated by the PERK/eIF-2/ATF4/CHOP pathway or another UPR-dependent pathway. Other mechanisms of cell death may play contributory or even dominant roles depending on cell type. As shown in a proteomic study with WA, the compounds appear to function largely as electrophilic reactants, indiscriminately modifying reachable nucleophilic amino acid side chains of proteins. However, a remarkable degree of target specificity is imparted by the cellular context.

Peptides from Harpadon nehereus Bone Ameliorate Angiotensin II-Induced HUVEC Injury and Dysfunction through Activation of the AKT/eNOS and Nrf2 Pathway

Angiotensin II (Ang II)-induced vascular endothelial cell injury and dysfunction are important pathophysiological factors in the occurrence and development of hypertension. In this study, the amelioration effects of two peptides KA-8 (KLHDEEVA) and PG-7 (PSRILYG) from Harpadon nehereus bone on Ang II-induced damage and dysfunction in human umbilical vein endothelial cells (HUVECs) were investigated. The results showed that they could significantly decrease the reactive oxygen species (ROS) level and increase the activity of antioxidant enzymes in Ang II-induced HUVEC. Two peptides, especially PG-7, significantly upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, PG-7 significantly reduced the level of expression of endothelin-1(ET-1) and increased the phosphorylation level of phosphoinositide 3-kinase (PI3K), serine/threonine kinase (AKT), and nitric oxide synthase (eNOS). These results indicated that the two peptides, especially PG-7, can ameliorate angiotensin II-induced HUVEC injury and dysfunction through activation of the AKT/eNOS and Nrf2 pathway. Furthermore, PG-7 showed a stronger affinity with angiotensin-converting enzyme (ACE) and ACE inhibitory than KA-8. In conclusion, peptide PG-7 reveals potential in the prevention and treatment of hypertension.

Celastrol functions as an emerging manager of lipid metabolism: Mechanism and therapeutic potential

Lipid metabolism disorders are pivotal in the development of various lipid-related diseases, such as obesity, atherosclerosis, non-alcoholic fatty liver disease, type 2 diabetes, and cancer. Celastrol, a bioactive compound extracted from the Chinese herb Tripterygium wilfordii Hook F, has recently demonstrated potent lipid-regulating abilities and promising therapeutic effects for lipid-related diseases. There is substantial evidence indicating that celastrol can ameliorate lipid metabolism disorders by regulating lipid profiles and related metabolic processes, including lipid synthesis, catabolism, absorption, transport, and peroxidation. Even wild-type mice show augmented lipid metabolism after treatment with celastrol. This review aims to provide an overview of recent advancements in the lipid-regulating properties of celastrol, as well as to elucidate its underlying molecular mechanisms. Besides, potential strategies for targeted drug delivery and combination therapy are proposed to enhance the lipid-regulating effects of celastrol and avoid the limitations of its clinical application.

Radical oxygen species: an important breakthrough point for botanical drugs to regulate oxidative stress and treat the disorder of glycolipid metabolism

Background: The incidence of glycolipid metabolic diseases is extremely high worldwide, which greatly hinders people's life expectancy and patients' quality of life. Oxidative stress (OS) aggravates the development of diseases in glycolipid metabolism. Radical oxygen species (ROS) is a key factor in the signal transduction of OS, which can regulate cell apoptosis and contribute to inflammation. Currently, chemotherapies are the main method to treat disorders of glycolipid metabolism, but this can lead to drug resistance and damage to normal organs. Botanical drugs are an important source of new drugs. They are widely found in nature with availability, high practicality, and low cost. There is increasing evidence that herbal medicine has definite therapeutic effects on glycolipid metabolic diseases. Objective: This study aims to provide a valuable method for the treatment of glycolipid metabolic diseases with botanical drugs from the perspective of ROS regulation by botanical drugs and to further promote the development of effective drugs for the clinical treatment of glycolipid metabolic diseases. Methods: Using herb*, plant medicine, Chinese herbal medicine, phytochemicals, natural medicine, phytomedicine, plant extract, botanical drug, ROS, oxygen free radicals, oxygen radical, oxidizing agent, glucose and lipid metabolism, saccharometabolism, glycometabolism, lipid metabolism, blood glucose, lipoprotein, triglyceride, fatty liver, atherosclerosis, obesity, diabetes, dysglycemia, NAFLD, and DM as keywords or subject terms, relevant literature was retrieved from Web of Science and PubMed databases from 2013 to 2022 and was summarized. Results: Botanical drugs can regulate ROS by regulating mitochondrial function, endoplasmic reticulum, phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT), erythroid 2-related factor 2 (Nrf-2), nuclear factor κB (NF-κB), and other signaling pathways to improve OS and treat glucolipid metabolic diseases. Conclusion: The regulation of ROS by botanical drugs is multi-mechanism and multifaceted. Both cell studies and animal experiments have demonstrated the effectiveness of botanical drugs in the treatment of glycolipid metabolic diseases by regulating ROS. However, studies on safety need to be further improved, and more studies are needed to support the clinical application of botanical drugs.

LOX-1 Regulation in Anti-atherosclerosis of Active Compounds of Herbal Medicine: Current Knowledge and the New Insight

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) have recently been identified to be closely related to the occurrence and development of atherosclerosis (AS). A growing body of evidence has suggested Chinese medicine takes unique advantages in preventing and treating AS. In this review, the related research progress of AS and LOX-1 has been summarized. And the anti-AS effects of 10 active components of herbal medicine through LOX-1 regulation have been further reviewed. As a potential biomarker and target for intervention in AS, LOX-1 targeted therapy might provide a promising and novel approach to atherosclerotic prevention and treatment.

Atherosclerosis: The Involvement of Immunity, Cytokines and Cells in Pathogenesis, and Potential Novel Therapeutics

As a leading contributor to coronary artery disease (CAD) and stroke, atherosclerosis has become one of the major cardiovascular diseases (CVD) negatively impacting patients worldwide. The endothelial injury is considered to be the initial step of the development of atherosclerosis, resulting in immune cell migration and activation as well as inflammatory factor secretion, which further leads to acute and chronic inflammation. In addition, the inflammation and lipid accumulation at the lesions stimulate specific responses from different types of cells, contributing to the pathological progression of atherosclerosis. As a result, recent studies have focused on using molecular biological approaches such as gene editing and nanotechnology to mediate cellular response during atherosclerotic development for therapeutic purposes. In this review, we systematically discuss inflammatory pathogenesis during the development of atherosclerosis from a cellular level with a focus on the blood cells, including all types of immune cells, together with crucial cells within the blood vessel, such as smooth muscle cells and endothelial cells. In addition, the latest progression of molecular-cellular based therapy for atherosclerosis is also discussed. We hope this review article could be beneficial for the clinical management of atherosclerosis.

Natural drugs targeting inflammation pathways can be used to treat atherosclerosis

Atherosclerosis (AS) is the chronic gradual degradation of arteries in combination with inflammation. Currently, the main research focus has been on interactions between inflammatory cells, inflammatory mediators, and immune mechanisms, while some studies have reported natural drugs were exerting a critical role against AS, whereas the usage of natural drugs was always limited by various factors such as poor penetration across biological barriers, low bioavailability, and unclear mechanisms. Herein, we reviewed the potential targets for inflammation against AS, discussed the underlying mechanisms of natural drugs for AS, particularly highlighted the dilemma of current research, and finally, offered perspectives in this field.

Contribution of Oxidative Stress (OS) in Calcific Aortic Valve Disease (CAVD): From Pathophysiology to Therapeutic Targets

Calcific aortic valve disease (CAVD) is a major cause of cardiovascular mortality and morbidity, with increased prevalence and incidence. The underlying mechanisms behind CAVD are complex, and are mainly illustrated by inflammation, mechanical stress (which induces prolonged aortic valve endothelial dysfunction), increased oxidative stress (OS) (which trigger fibrosis), and calcification of valve leaflets. To date, besides aortic valve replacement, there are no specific pharmacological treatments for CAVD. In this review, we describe the mechanisms behind aortic valvular disease, the involvement of OS as a fundamental element in disease progression with predilection in AS, and its two most frequent etiologies (calcific aortic valve disease and bicuspid aortic valve); moreover, we highlight the potential of OS as a future therapeutic target.

Celastrol: A Promising Agent Fighting against Cardiovascular Diseases

Cardiovascular diseases (CVD) are leading causes of morbidity and mortality worldwide; therefore, seeking effective therapeutics to reduce the global burden of CVD has become increasingly urgent. Celastrol, a bioactive compound isolated from the roots of the plant Tripterygium wilfordii (TW), has been attracting increasing research attention in recent years, as it exerts cardiovascular treatment benefits targeting both CVD and their associated risk factors. Substantial evidence has revealed a protective role of celastrol against a broad spectrum of CVD including obesity, diabetes, atherosclerosis, cerebrovascular injury, calcific aortic valve disease and heart failure through complicated and interlinked mechanisms such as direct protection against cardiomyocyte hypertrophy and death, and indirect action on oxidation and inflammation. This review will mainly summarize the beneficial effects of celastrol against CVD, largely based on in vitro and in vivo preclinical studies, and the potential underlying mechanisms. We will also briefly discuss celastrol’s pharmacokinetic limitations, which hamper its further clinical applications, and prospective future directions.

Physicochemical Properties of Collagen from the Bone of Harpadon nehereus and Its Protective Effects against Angiotensin II-Induced Injury in Human Umbilical Vein Endothelial Cells

The physicochemical characterization of a new collagen from the bone of Harpadon nehereus (HNBC) and its protective effects against Ang II-induced injury of human umbilical vein endothelial cells (HUVEC) were investigated. The triple helix of HNBC analyzed by SDS-PAGE was formed as (α₁)₂α₂, belonging to type I collagen. UV spectra showed that HNBC had a maximum absorbance at 230 nm. FTIR spectra indicated the triple helical structure and activity of HNBC. The high solubility of HNBC was observed in the low pH ranges (≤4) and NaCl concentrations (≤2%, w/v). The maximum transition (T _m) of HNBC was determined to be 48.5 °C. The amino acid composition analysis showed that glycine, glutamic acid, proline, and alanine were the abundant amino acids available in HNBC. HNBC showed free radical (DPPH and OH·) scavenging activities in the tested concentrations (0.5-6 mg/mL). In addition, HNBC could effectively protect against Ang II-induced injury of HUVEC by increasing the activities of antioxidant enzymes, such as CAT, SOD, and GSH-Px. Overall, collagen from the bone of H. nehereus has promising prospects in functional food and biomedical industries.

Oxidative Stress in Calcific Aortic Valve Stenosis: Protective Role of Natural Antioxidants

Calcific aortic valve stenosis (CAVS) is the most prevalent heart valvular disease worldwide and a slowly progressive disorder characterized by thickening of the aortic valve, calcification, and subsequent heart failure. Valvular calcification is an active cell regulation process in which valvular interstitial cells involve phenotypic conversion into osteoblasts/chondrocytes-like cells. The underlying pathophysiology is complicated, and there have been no pharmacological treatments for CAVS to date. Recent studies have suggested that an increase in oxidative stress is the major trigger of CAVS, and natural antioxidants could ameliorate the detrimental effects of reactive oxygen species in the pathogenesis of CAVS. It is imperative to review the current findings regarding the role of natural antioxidants in CAVS, as they can be a promising therapeutic approach for managing CAVS, a disorder currently without effective treatment. This review summarizes the current findings on molecular mechanisms associated with oxidative stress in the development of valvular calcification and discusses the protective roles of natural antioxidants in the prevention and treatment of CAVS.

Reactive Oxygen Species in Cardiovascular Calcification: Role of Medicinal Plants

Cardiovascular calcification, including vascular calcification and calcific aortic valve disease (CAVD), is a serious worldwide health problem, especially in older adults. The mechanisms underlying cardiovascular calcifications are complex and multifactorial. An increase in reactive oxygen species (ROS) and oxidative stress play important roles in the initiation and development of cardiovascular calcification. This mini-review summarizes the recent evidence that supports the association of ROS with vascular calcification and CAVD and discusses the role of medicinal plants for the prevention and treatment of cardiovascular calcification.

The Protective Role of Celastrol in Renal Ischemia-Reperfusion Injury by Activating Nrf2/HO-1, PI3K/AKT Signaling Pathways, Modulating NF-κb Signaling Pathways, and Inhibiting ERK Phosphorylation

Celastrol, a natural triterpenoid derived from Tripterygium wilfordii, possesses numerous biological effects. We investigated celastrol's antioxidant potential through nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) and its effect on phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling, nuclear factor-kappa B (NF-κB) pathways, and extracellular signal-regulated kinase (ERK) activation in kidney ischemia-reperfusion injury (IRI) rat model. Rats were given celastrol 2 mg/kg orally for 1 week before subjection to renal ischemia-reperfusion surgery. Kidney functions, renal MDA, and reduced glutathione were determined; also, renal levels of ERK1/2, HO-1, PI3K, IL-6, TNF-α, IκBα, NF-κB/p65, and cleaved caspase-3 were measured. In addition, gene expression of kidney injury molecule-1 (KIM-1), Nrf-2, and AKT were determined. Celastrol pretreatment attenuated oxidative stress and increased Nrf2 gene expression and HO-1 level. Also, it activated the PI3K/AKT signaling pathway and decreased the p-ERK:t- ERK ratio and NFκBp65 level, with a remarkable decrease in inflammatory cytokines and cleaved caspase-3 levels compared with those in renal IRI rats. Conclusively, celastrol showed a reno-protective potential against renal IRI by suppressing oxidative stress through enhancing the Nrf2/HO-1 pathway, augmenting cell survival PI3K/AKT signaling pathways, and reducing inflammation by inhibiting NF-κB activation.

A meta-analysis of prospective cohort studies of flavonoid subclasses and stroke risk

Epidemiological studies indicate that higher intakes of flavonoids are associated with reduced stroke risk, however, which subtypes play significant roles to protect against stroke remain unclear. A systematic literature search in PubMed and Web of Science databases was performed up to Oct. 2021. Flavonoids or their subtypes (flavanol, flavanone, flavone, flavan-3-ol, isoflavone, or anthocyanin) were paired with stoke as the search term. Multivariate-adjusted relative risks (RRs) with 95% confidence intervals (CIs) for the highest versus the lowest category were pooled by using a random-effects model. Dose-response analysis was implemented by using a restricted cubic spline regression model. Ten independent prospective cohort studies with 387,076 participants and 9,564 events were included. Higher intakes of flavanones were inversely associated with stroke risk (RR = 0.85; 95%CI: 0.78, 0.93). Dose-response analysis showed that 50 mg/day increment of flavanones was associated with 11% reduction in stroke risk (RR = 0.89; 95%CI: 0.84, 0.94). Flavan-3-ols was marginally inversely associated with stroke risk (RR = 0.92; 95%CI: 0.82, 1.02). Dose-response analysis showed that 200 mg/day increment of flavan-3-ols was associated with 14% reduction in stroke risk (RR = 0.86; 95%CI: 0.75, 0.98). The non-significant association was observed with respect to other flavonoid subclasses. This study demonstrated higher intakes of flavanones and flavan-3-ols were associated with a lower risk of stroke. Dietary intakes of lemon and citrus rich in flavanones and flavan-3-ols might have beneficial functions for the protection against stroke. The findings of these associations of the present study need to be confirmed in other regions and ethnic origins.

Phage Display Preparation of Specific Polypeptides in Atherosclerotic Foam Cells

Atherosclerosis and related complications are the most common causes of death in modern societies. Macrophage-derived foam cells play critical roles in the initiation and progression of atherosclerosis. Effective, rapid, and instrument-independent detection in the early stage of chronic atherosclerosis progression could provide an opportunity for early intervention and treatment. Therefore, as a starting point, in this study, we aimed to isolate and prepare foam cell-specific polypeptides using a phage display platform. The six target polypeptides, which were acquired in this study, were evaluated by ELISA and showed strong specificity with foam cells. Streptavidin coupled quantum dots (QDs) were used as fluorescence developing agents, and images of biotin-modified polypeptides specifically binding with foam cells were clearly observed. The polypeptides obtained in this study could lay the foundation for developing a rapid detection kit for early atherosclerosis lesions and could provide new materials for research on the mechanisms of foam cell formation and the development of blocking drugs.

Role of Lipid Accumulation and Inflammation in Atherosclerosis: Focus on Molecular and Cellular Mechanisms

Atherosclerosis is a chronic lipid-driven and maladaptive inflammatory disease of arterial intima. It is characterized by the dysfunction of lipid homeostasis and signaling pathways that control the inflammation. This article reviews the role of inflammation and lipid accumulation, especially low-density lipoprotein (LDL), in the pathogenesis of atherosclerosis, with more emphasis on cellular mechanisms. Furthermore, this review will briefly highlight the role of medicinal plants, long non-coding RNA (lncRNA), and microRNAs in the pathophysiology, treatment, and prevention of atherosclerosis. Lipid homeostasis at various levels, including receptor-mediated uptake, synthesis, storage, metabolism, efflux, and its impairments are important for the development of atherosclerosis. The major source of cholesterol and lipid accumulation in the arterial wall is proatherogenic modified low-density lipoprotein (mLDL). Modified lipoproteins, such as oxidized low-density lipoprotein (ox-LDL) and LDL binding with proteoglycans of the extracellular matrix in the intima of blood vessels, cause aggregation of lipoprotein particles, endothelial damage, leukocyte recruitment, foam cell formation, and inflammation. Inflammation is the key contributor to atherosclerosis and participates in all phases of atherosclerosis. Also, several studies have shown that microRNAs and lncRNAs have appeared as key regulators of several physiological and pathophysiological processes in atherosclerosis, including regulation of HDL biogenesis, cholesterol efflux, lipid metabolism, regulating of smooth muscle proliferation, and controlling of inflammation. Thus, both lipid homeostasis and the inflammatory immune response are closely linked, and their cellular and molecular pathways interact with each other.

Celastrol ameliorates vascular neointimal hyperplasia through Wnt5a-involved autophagy

Neointimal hyperplasia caused by the excessive proliferation of vascular smooth muscle cells (VSMCs) is the pathological basis of restenosis. However, there are few effective strategies to prevent restenosis. Celastrol, a pentacyclic triterpene, has been recently documented to be beneficial to certain cardiovascular diseases. Based on its significant effect on autophagy, we proposed that celastrol could attenuate restenosis through enhancing autophagy of VSMCs. In the present study, we found that celastrol effectively inhibited the intimal hyperplasia and hyperproliferation of VSMCs by inducing autophagy. It was revealed that autophagy promoted by celastrol could induce the lysosomal degradation of c-MYC, which might be a possible mechanism contributing to the reduction of VSMCs proliferation. The Wnt5a/PKC/mTOR signaling pathway was found to be an underlying mechanism for celastrol to induce autophagy and inhibit the VSMCs proliferation. These observations indicate that celastrol may be a novel drug with a great potential to prevent restenosis.

Nanotechnology-Based Celastrol Formulations and Their Therapeutic Applications

Celastrol (also called tripterine) is a quinone methide triterpene isolated from the root extract of Tripterygium wilfordii (thunder god vine in traditional Chinese medicine). Over the past two decades, celastrol has gained wide attention as a potent anti-inflammatory, anti-autoimmune, anti-cancer, anti-oxidant, and neuroprotective agent. However, its clinical translation is very challenging due to its lower aqueous solubility, poor oral bioavailability, and high organ toxicity. To deal with these issues, various formulation strategies have been investigated to augment the overall celastrol efficacy in vivo by attempting to increase the bioavailability and/or reduce the toxicity. Among these, nanotechnology-based celastrol formulations are most widely explored by pharmaceutical scientists worldwide. Based on the survey of literature over the past 15 years, this mini-review is aimed at summarizing a multitude of celastrol nanoformulations that have been developed and tested for various therapeutic applications. In addition, the review highlights the unmet need in the clinical translation of celastrol nanoformulations and the path forward.

Celastrol Inhibits the Proliferation and Decreases Drug Resistance of Cisplatin-Resistant Gastric Cancer SGC7901/DDP Cells

BACKGROUND

This study aimed to determine the effect and mechanism of Celastrol inhibiting the proliferation and decreases drug resistance of cisplatin-resistant gastric cancer cells.

OBJECTIVE

To explore the effect and mechanism of Celastrol on proliferation and drug resistance of human gastric cancer cisplatin-resistant cells SGC7901/DDP.

METHODS

The thiazole blue (MTT) method was used to detect the sensitivity of human gastric cancer cisplatin-resistant cells SGC7901/DPP to cisplatin and Celastrol to determine the Drug resistance index (DRI). According to the half inhibitory concentration (IC50) value, the action concentration of the following experimental drugs was set to reduce the cytotoxicity; Annexin V-FITC/PI double staining method was used to detect the apoptosis of SGC7901/DDP cells induced by Celastrol; Western Blot was used to examine the expression levels of P-glycoprotein (P-gp), Multidrug Resistance Associated Protein 1 (MRP1), Breast Cancer Resistance Associated Protein (Breast Cancer Resistance)-relative protein (BCRP), and mechanistic Target of Rapamycin (mTOR) pathway related proteins; Real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA expression levels of P-gp, MRP1, and BCRP.

RESULTS

(1) Compared with the control group (We set the untreated group as the control group), the proliferation of the SGC7901/DPP cells was significantly inhibited after treating with 0.1-6.4μmol/L Celastrol in a time- and concentration-dependent manner (P<0.05). The Drug resistance index DRI of the SGC7901/DPP cells to DDP was 5.64. (2) Compared with the control group, Celastrol could significantly inhibit the proliferation and induce the apoptosis of the SGC7901/DPP cells (P<0.05). (3) The mRNA and protein expression levels of P-gp, MRP1, and BCRP in the SGC7901/DPP cells were significantly higher than those in the SGC7901 cells. However, after treating with Celastrol, the expression levels of P-gp, MRP1, and BCRP in the SGC7901/DPP cells were significantly reduced (P<0.05). (4) Compared with the control group, the Celastrol treatment also reduced the expression of the mTOR signaling pathway related proteins, suggesting that the mTOR signaling pathway may be involved in the process of Celastrol inhibiting the proliferation of the SGC7901/DDP cells and reducing their drug resistance. (5) Significantly, the combination of Celastrol and DDP reduced the expression of P-gp, MRP1, and BCRP in the SGC7901/DPP cells.

CONCLUSION

Celastrol can inhibit the proliferation of the SGC7901/DDP cells, induce their apoptosis, and reduce the expression of drug resistance genes, probably by inhibiting the expression of the proteins related to the mTOR signaling pathway.

Targeting and clearance of senescent foamy macrophages and senescent endothelial cells by antibody-functionalized mesoporous silica nanoparticles for alleviating aorta atherosclerosis

Senescent cells drive atherosclerosis at all stages and contribute to cardiovascular disease. However, the markers in these senescent aortic plaques have not been well studied, creating a huge obstacle in the exploration of a precise and efficient system for atherosclerosis treatment. Recently, CD9 has been found to induce cellular senescence and aggravated atherosclerotic plaque formation in apolipoprotein E knockout (ApoE^-/-) mice. In the present study, this result has been leveraged to develop CD9 antibody-modified, hyaluronic acid-coated mesoporous silica nanoparticles with a hyaluronidase-responsive drug release profile. In invitro models of senescent foamy macrophages and senescent endothelial cells stimulated with oxidized high-density-lipoprotein, the CD9 antibody-modified mesoporous silica nanoparticles exhibit high cellular uptake; reduce the reactive oxygen species level, high-density lipoprotein oxidation, and production of TNF-α and IL-6; and attenuate the senescence process, contributing to improved cell viability. In vivo experiment demonstrated that these nanoparticles can successfully target the senescent lesion areas, deliver the anti-senescence drug rosuvastatin to the senescent atherosclerotic plaques (mainly endothelial cells and macrophages), and alleviate the progression of atherosclerosis in ApoE^-/- mice. By providing deep insight regarding the markers in senescent atherosclerotic plaque and developing a nano-system targeting this lesion area, the study proposes a novel and an accurate therapeutic approach for mitigating atherosclerosis through senescent cell clearance.

Current advances in the nano-delivery of celastrol for treating inflammation-associated diseases

Inflammation is ubiquitous in the body, and uncontrolled inflammation often contributes to various diseases. Celastrol, a compound isolated from a Chinese medicinal herb, holds great potential in treating multiple inflammation-associated diseases. However, its further clinical use is limited by its poor solubility, bioavailability, and high organ toxicity. With the advancement of nanotechnology, the nano-delivery of celastrol can effectively improve its oral bioavailability, maximize its efficacy and minimize its side effects. Here, we summarize the roles of celastrol in the treatment of various inflammation-associated diseases, with a special emphasis on its role in modulating immune cell signaling or non-immune cell signaling within the inflammatory microenvironment, and we highlight the latest advances in nano-delivery strategies for celastrol to treat diseases associated with inflammation.

Celastrol regulates bone marrow mesenchymal stem cell fate and bone-fat balance in osteoporosis and skeletal aging by inducing PGC-1α signaling

Celastrol has recently been identified as a prospective new treatment for obesity and several metabolic complications. However, the effect of Celastrol in osteoporosis (OP) remains unknown. In this study, we demonstrated that Celastrol promotes osteoblast differentiation and prevents adipocyte differentiation in bone marrow mesenchymal stem cells (BM-MSCs) in vitro. Mechanistically, Celastrol was able to control the differentiation of BM-MSCs by stimulating PGC-1α signaling. Moreover, administration of Celastrol could alleviate bone loss and bone marrow adipose tissue (MAT) accumulation in ovariectomized (OVX) mice and aged mice. Together, these results recommended that Celastrol could regulate BM-MSCs fate and bone-fat balance in OP and skeletal aging by stimulating PGC-1α, which might act as a possible therapeutic target for OP and for the prevention of skeletal aging.

Activation of CREB Protein With Tabersonine Attenuates STAT3 During Atherosclerosis in Apolipoprotein E-Deficient Mice

Objective:

Atherosclerosis is a pathological condition of fat deposition in the arteries, which causes cardiovascular disorders. Management of atherosclerosis remains a challenge and conventional drugs used for its management have several limitations. This study evaluated the protective effect of tabersonine against atherosclerosis and assessed its molecular mechanism of action.

Methods:

Atherosclerosis was induced by feeding apolipoprotein E (ApoE)-deficient mice a high-fat diet. Mice were treated with 20 or 40 mg/kg of tabersonine intraperitoneally for the 12-week duration of the study. Atherosclerosis markers and nitric oxide were measured in the sera of ApoE-deficient mice. Mediators of inflammation and markers of oxidative stress were assessed using enzyme-linked immunosorbent assays. Western blotting, quantitative reverse transcriptase polymerase chain reaction, and immunohistochemistry analyses were conducted to determine the protein expression in aortic tissue.

Results:

The tabersonine-treatment groups had an improved lipid profile and enhanced liver function, compared to the ApoE treatment group. Tabersonine treatment resulted in reduced levels of nitric oxide, cytokines, and oxidative stress, compared to the ApoE group. The altered expression levels of protein inhibitor activated STAT-3 (PIAS3), signal transducer and activator of transcription-3 (STAT-3), and nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IkBα) in ApoE-deficient mice were ameliorated by tabersonine treatment. Moreover, cAMP-response-element-binding (CREB) expression was elevated in aortic tissue of tabersonine treatment groups, compared to the ApoE group.

Conclusion:

These results suggested that tabersonine ameliorates the expression of STAT-3 by activating CREB protein in atherosclerotic ApoE-deficient mice.

Enhanced Inflammatory Reaction and Thrombosis in High-Fat Diet-Fed ApoE-/- Mice are Attenuated by Celastrol

OBJECTIVE

High-fat diet (HFD) increases the risk of inflammatory reaction and acute arterial thrombosis. Celastrol has been confirmed to regulate inflammatory cytokine levels in atherosclerotic animal models. However, the anti-thrombotic effects of celastrol have remained to be fully demonstrated. The present study was performed to investigate the beneficial effect of celastrol in HFD-induced inflammatory reaction and thrombosis in apolipoprotein (apo)E^-/- mice.

MATERIALS AND METHODS

Thrombogenic mice model was established using HFD-fed apoE^-/- mice. The levels of mRNA and protein were assayed by RT-qPCR and western blotting, respectively. Immunohistochemistry (IHC) staining was performed to measure the protein expression of matrix metalloproteinase-2 and matrix metalloproteinase-9 in the aortic endothelium of HFD-fed apoE^-/- mice.

RESULTS

The results demonstrated that the effect of HFD on inflammatory cytokines in mice with apoE^-/- background was reversed by celastrol administration, and celastrol treatment inhibited the NOD-like receptor family, pyrin domain containing 3 (NLRP3)/caspase-1/interleukin-1β signaling cascades in peripheral blood mononuclear cells from HFD-fed apoE^-/- mice. In addition, HFD enhanced adenosine diphosphate-induced platelet aggregation in normal C57BL/6 and apoE^-/- mice, while celastrol administration reversed this. Furthermore, celastrol inhibited the pro-thrombotic effects of HFD in apoE^-/- mice, and the underlying mechanism was mediated, at least partially, through the suppression of matrix metalloproteinase-2 and -9 expression.

CONCLUSIONS

Celastrol administration significantly attenuated HFD-induced inflammatory reaction, platelet aggregation and thrombosis in apoE^-/- mice, and celastrol may be used as a drug for the prevention of HFD-induced inflammatory reaction and thrombus.

Celastrol Alleviates Aortic Valve Calcification Via Inhibition of NADPH Oxidase 2 in Valvular Interstitial Cells

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The reactive oxygen species–generating enzyme Nox2 is up-regulated in the leaflets of both rabbit and human with CAVD.

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Nox2 is markedly induced in cultured porcine AVICs after osteogenic stimulation. Knockdown of endogenous Nox2 substantially suppressed AVIC calcification.

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Celastrol, a natural compound capable of inhibiting Nox2 activity, significantly decreased AVIC calcification in vitro, and mitigated the severity of aortic valve fibrosis, calcification, and stenosis in a rabbit model of CAVD in vivo.

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The protective effects of celastrol may, in part, involve the inhibition of Nox2-mediated glycogen synthase kinase 3 beta/β-catenin pathway.

This study sought to investigate whether reactive oxygen species (ROS)–generating reduced nicotinamide adenine dinucleotide phosphate oxidase 2 (Nox2) contributes to calcific aortic valve disease (CAVD) or whether celastrol, a natural Nox2 inhibitor, may provide potential therapeutic target for CAVD. CAVD is an active and cellular-driven fibrocalcific process characterized by differentiation of aortic valvular interstitial cells (AVICs) toward an osteogenic-like phenotype. ROS levels increase in calcified aortic valves, while the sources of ROS and their roles in the pathogenesis of CAVD are elusive. The roles of Nox2 and the effects of celastrol were studied using cultured porcine AVICs in vitro and a rabbit CAVD model in vivo. Nox2 proteins were significantly upregulated in human aortic valves with CAVD. In vitro, Nox2 was markedly induced upon stimulation of AVICs with osteogenic medium, along with the increases in ROS production and calcium nodule formation. Celastrol significantly decreased calcium deposition of AVICs by 35%, with a reduction of ROS generation. Knockdown of endogenous Nox2 substantially suppressed AVIC calcification by 39%, the inhibitory effect being similar to celastrol treatment. Mechanistically, either celastrol treatment or knockdown of Nox2 significantly inhibited glycogen synthase kinase 3 beta/β-catenin signaling, leading to attenuation of fibrogenic and osteogenic responses of AVICs. In a rabbit CAVD model, administration of celastrol significantly reduced aortic valve ROS production, fibrosis, calcification, and severity of aortic stenosis, with less left ventricular dilatation and better preserved contractile function. Upregulation of Nox2 is critically involved in CAVD. Celastrol is effective to alleviate CAVD, likely through the inhibition of Nox2-mediated glycogen synthase kinase 3 beta/β-catenin pathway in AVICs.

Anti-Atherosclerotic Effects of Fruits of Vitex rotundifolia and Their Isolated Compounds via Inhibition of Human LDL and HDL Oxidation

Low-density lipoprotein (LDL) and high-density lipoprotein (HDL) oxidation are well known to increase the risk for atherosclerosis. In our ongoing research on natural products with inhibitory activities against oxidation of lipoproteins, fruits of Vitex rotundifolia were found to be highly active. There is no report on the effects on LDL and HDL oxidation. Herein, we investigated the inhibitory effects of V. rotundifolia fruit extract and its six compounds, which are: (1) artemetin, (2) casticin, (3) hesperidin, (4) luteolin, (5) vitexin, and (6) vanillic acid, against LDL and HDL oxidation. The LDL and HDL oxidations were determined by measuring production of conjugated dienes and thiobarbituric acid reactive substances, amount of hyperchromicity and carbonyl content, change in electrical charge, and apoA-I aggregation. In addition, the contents of the compounds in the extracts were analyzed using HPLC-DAD. Consequently, extracts of Vitex rotundifolia fruits and compounds 2 and 4 suppressed oxidation of LDL and HDL, showing inhibition of lipid peroxidation, decrease of negative charges in lipoproteins, reduction of hyperchromicity, decrease in carbonyl contents, and prevention of apoA-I aggregation. In particular, compounds 2 and 4 exhibited more potent inhibitory effect on oxidation of LDL and HDL than the extracts, suggesting their protective role against atherosclerosis via inhibition of LDL and HDL oxidation. The contents of artemetin, casticin, and vanillic acid in the extracts were 1.838 ± 0.007, 8.629 ± 0.078, and 1.717 ± 0.006 mg/g, respectively.

Naringin Reverses High-Cholesterol Diet-Induced Vascular Dysfunction and Oxidative Stress in Rats via Regulating LOX-1 and NADPH Oxidase Subunit Expression

Hypercholesterolaemia is associated with oxidative stress and endothelial dysfunction and leads to the development of atherosclerosis. Naringin exhibits cardiovascular protective and antioxidant properties. Therefore, the aim of this study was to assess the effect of naringin administration on vascular oxidative stress and endothelial dysfunction in hypercholesterolaemic rats and to elucidate its underlying mechanism. Sprague Dawley rats were fed a diet with 1.5% cholesterol (HCD) for 8 weeks to induce hypercholesterolaemia. Naringin (100 mg/kg body weight) was orally administrated to rats during the last 4 weeks of the diet treatment. After 8 weeks, the thoracic aorta was isolated to determine vascular function and nitric oxide (NO) levels. The aortic superoxide anion (O₂⁻) level was detected using dihydroethidium (DHE) fluorescence staining. Protein expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, and inducible nitric oxide synthase (iNOS), as well as oxidative damage markers, was also evaluated in aortae. Naringin treatment of hypercholesterolaemic rats enhanced aortic NO levels, restored endothelium-dependent responses to acetylcholine (ACh), and reduced aortic O₂⁻ levels. Furthermore, naringin treatment decreased LOX-1, NADPH oxidase subunits (p47^phox, Nox2, and Nox4), and iNOS as well as oxidative damage markers (3-nitrotyrosine (3-NT) and 4-hydroxynonenal (4-HNE)) expression in aortic tissues from hypercholesterolaemic rats. These results demonstrate that naringin treatment improves endothelium dysfunction in hypercholesterolaemic rats, at least partially by decreasing oxidative stress via downregulation of LOX-1 and NADPH oxidase.

Efficacy of Terpenoid in Attenuating Aortic Atherosclerosis in Apolipoprotein-E Deficient Mice: A Meta-Analysis of Animal Studies

Background

The apolipoprotein E knockout (ApoE -/-) mouse model is well established for the study of terpenoids in the prevention of atherosclerosis. Studies investigating the clinical benefit of terpenoids in humans are scarce. This systematic review and meta-analysis evaluated the effects of terpenoid administration on atherosclerotic lesion area in ApoE -/- mice.

Methods

A comprehensive literature search using PubMed, Embase, and the Cochrane Library databases was performed to identify studies that assessed the effects of terpenoids on atherosclerosis in ApoE -/- mice. The primary outcome was atherosclerotic lesion area, and study quality was estimated using SYRCLE's risk of bias tool.

Results

The meta-analysis included 25 studies. Overall, terpenoids significantly reduced atherosclerotic lesion area when compared to vehicle control (P<0.00001; SMD: -0.55; 95% CI: -0.72, -0.39). In terpenoid type and dose subgroup analyses, sesquiterpenoid (P=0.002; SMD -0.93; 95% CI: -1.52, -0.34), diterpenoid (P=0.01; SMD: -0.30; 95% CI: -0.54, -0.06), triterpenoid (P<0.00001; SMD: -0.66; 95% CI: -0.94, -0.39), tetraterpenoid (P<0.0001; SMD: -1.81; 95% CI: -2.70, -0.91), low dose (P=0.0001; SMD: -0.51; 95% CI: -0.76, -0.25), medium dose (P<0.0001; SMD: -0.48; 95% CI: -0.72, -0.24), and high dose (P=0.002; SMD: -1.07; 95% CI: -1.74, -0.40) significantly decreased atherosclerotic lesion area when compared to vehicle control. PROSPERO register number is CRD42019121176.

Conclusion

Sesquiterpenoid, diterpenoid, triterpenoid, and tetraterpenoid have potential as antiatherosclerotic agents with a wide range of doses. This systematic review provides a reference for research programs aimed at the development of terpenoid-based clinical drugs.

In Vitro Vascular-Protective Effects of a Tilapia By-Product Oligopeptide on Angiotensin II-Induced Hypertensive Endothelial Injury in HUVEC by Nrf2/NF-κB Pathways

Angiotensin II (Ang II) is closely involved in endothelial injury during the development of hypertension. In this study, the protective effects of the tilapia by-product oligopeptide Leu-Ser-Gly-Tyr-Gly-Pro (LSGYGP) on oxidative stress and endothelial injury in Angiotensin II (Ang II)-stimulated human umbilical vein endothelial cells (HUVEC) were evaluated. LSGYGP dose-dependently suppressed the fluorescence intensities of nitric oxide (NO) and reactive oxygen species (ROS), inhibited the nuclear factor-kappa B (NF-κB) pathway, and reduced inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and endothelin-1 (ET-1) expression, as shown by western blot. In addition, it attenuated the expression of gamma-glutamyltransferase (GGT) and heme oxygenase 1 (HO-1), as well as increasing superoxide dismutase (SOD) and glutathione (GSH) expression through the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway. Other experiments revealed that LSGYGP increased the apoptotic inhibition ratio between cleaved-caspase-3/procaspase-3, reduced expressions of pro-apoptotic ratio between Bcl-2/Bax, inhibited phosphorylation of mitogen-activated protein kinases (MAPK), and increased phosphorylation of the serine/threonine kinase (Akt) pathway. Furthermore, LSGYGP significantly decreased Ang II-induced DNA damage in a comet assay, and molecular docking results showed that the steady interaction between LSGYGP with NF-κB may be attributed to hydrogen bonds. These results suggest that this oligopeptide is effective in protecting against Ang II-induced HUVEC injury through the reduction of oxidative stress and alleviating endothelial damage. Thus, it has the potential for the therapeutic treatment of hypertension-associated diseases.

Protective effect of celastrol on myocardial ischemia-reperfusion injury

OBJECTIVE

Celastrol, a major active constituent of Tripterygium wilfordii, has antioxidant, anti-inflammatory, and anticancer effects. However, whether celastrol can exert protective effect on myocardial ischemia-reperfusion injury (MIRI) is unknown. The aim of this study was to test the protective effect of celastrol on MIRI and elucidate its underlying mechanism.

METHODS

Cardiomyocytes (H9c2 cells) were subjected to hypoxia for 8 h followed by reoxygenation for 4 h to create hypoxia/reoxygenation (H/R) model, an in vitro MIRI model. Celastrol was added to the medium 60 min before the H/R process . Cell viability was detected using MTT assay. Myocardial injury was evaluated by measuring lactate dehydrogenase (LDH) and creatine kinase MB isoenzyme (CK-MB) activity. Changes in mRNA and protein expression of TNF-α, IL-1ß, and nuclear factor-K B (NF-K B) were measured with RT-qPCR assay and western blot analysis.

RESULTS

Results showed that low-dose celastrol (20 and 50 nM) treatment significantly increased cell viability and decreased LDH and CK-MB activity in the condition of H/R, but high-dose celastrol (200 and 400 nM) resulted in extra injury to cardiomyocytes. Moreover, treatment with 50 nM celastrol significantly downregulated mRNA and protein expression of TNF-α and IL-1ß. Meanwhile, NF-K B mRNA and protein in the nucleus were also correspondingly reduced.

CONCLUSION

Our study demonstrated that low-dose celastrol could prevent MIRI in cardiomyocytes by inhibiting the activation of NF-K B, and celastrol may be a potential therapeutic agent for preventing MIRI.

Medicinal Herbs Effective Against Atherosclerosis: Classification According to Mechanism of Action

Atherosclerosis is a widespread and chronic progressive arterial disease that has been regarded as one of the major causes of death worldwide. It is caused by the deposition of cholesterol, fats, and other substances in the tunica intima which leads to narrowing of the blood vessels, loss of elasticity, and arterial wall thickening, thus causing difficulty in blood flow. Natural products have been used as one of the most important strategies for the treatment and prevention of cardiovascular diseases for a long time. In recent decades, as interests in natural products including medicinal herbs have increased, many studies regarding natural compounds that are effective against atherosclerosis have been conducted. The purpose of this review is to provide a brief over-view of the natural compounds that have been used for the treatment and prevention of atherosclerosis, and their mechanisms of action based on recent research.

Celastrol suppresses experimental autoimmune encephalomyelitis via MAPK/SGK1-regulated mediators of autoimmune pathology

OBJECTIVE AND DESIGN

Multiple sclerosis (MS) is a debilitating autoimmune disease involving immune dysregulation of the pathogenic T helper 17 (Th17) versus protective T regulatory (Treg) cell subsets, besides other cellular aberrations. Studies on the mechanisms underlying these changes have unraveled the involvement of mitogen-activated protein kinase (MAPK) pathway in the disease process. We describe here a gene expression- and bioinformatics-based study showing that celastrol, a natural triterpenoid, acting via MAPK pathway regulates the downstream genes encoding serum/glucocorticoid regulated kinase 1 (SGK1), which plays a vital role in Th17/Treg differentiation, and brain-derived neurotrophic factor (BDNF), which is a neurotrophic factor, thereby offering protection against experimental autoimmune encephalomyelitis (EAE) in mice.

METHODS

We first tested the gene expression profile of splenocytes of EAE mice in response to the disease-related antigen, myelin oligodendrocyte glycoprotein (MOG), and then examined the effect of celastrol on that profile.

RESULTS

Interestingly, celastrol reversed the expression of many MOG-induced genes involved in inflammation and immune pathology. The MAPK pathway involving p38MAPK and ERK was identified as one of the mediators of celastrol action. It involved suppression of SGK1 but upregulation of BDNF, which then contributed to protection against EAE.

CONCLUSION

Our results not only provide novel insights into disease pathogenesis, but also offer promising therapeutic targets for MS.

Celastrol ameliorates Aspergillus fumigatus keratitis via inhibiting LOX-1

PURPOSE

To investigate the effect of Celastrol (CLT) on Aspergillus fumigatus (A. fumigatus) keratitis.

METHODS

Primary peritoneal macrophages of C57BL/6 mice were pretreated with CLT before A. fumigatus hyphae stimulation. C57BL/6 mice were infected with A. fumigatus. Mice corneas were treated with CLT from 1 day post infection. Clinical score, PCR, ELISA and Western blot were used to test expression of anti-inflammatory mediators, proinflammatory mediators and Lectin-like oxidized low-density lipoprotein receptor 1(LOX-1). The protein levels of p38MAPK after pretreated with CLT in macrophages of C57BL/6 mice challenged with A. fumigatus were tested by Western blot.

RESULTS

C57BL/6 mice treated with CLT from 1 day post infection showed decreased disease, IL-1β, TNF-α, IL-10, TGF-β, MIP-2 and LOX-1 levels. CLT treatment markedly inhibiting mRNA and proteins levels of anti-inflammatory mediators, proinflammatory mediators and LOX-1 in macrophages of C57BL/6 mice compared with control group. CLT pretreatment before A. fumigatus stimulation obviously inhibiting protein levels of p38MAPK versus DMSO pretreated group in macrophages of C57BL/6 mice challenged with A. fumigatus.

CONCLUSION

These data provide evidences that CLT ameliorates A. fumigatus keratitis of C57BL/6 mice via inhibiting LOX-1. CLT pretreatment before A. fumigatus stimulation decreased levels of inflammation in macrophages of C57BL/6 mice, which may be regulated by p-p38MAPK.

Natural product celastrol suppressed macrophage M1 polarization against inflammation in diet-induced obese mice via regulating Nrf2/HO-1, MAP kinase and NF-κB pathways

Macrophage polarization is implicated in the inflammation in obesity. The aim of the present study was to examine the anti-inflammatory activities of botanical triterpene celastrol against diet-induced obesity. We treated diet-induced obese C57BL/6N male mice with celastrol (5, 7.5 mg/kg/d) for 3 weeks, and investigated macrophage M1/M2 polarization in adipose and hepatic tissues. Celastrol reduced fat accumulation and ameliorated glucose tolerance and insulin sensitivity. Celastrol down-regulated the mRNA levels of macrophage M1 biomarkers (e.g., IL-6, IL-1β, TNF-α, iNOS) in cell culture and in mice. The underlying mechanisms were investigated in murine macrophage RAW264.7 cells. Our results demonstrated that celastrol might control macrophage polarization through modulating the cross-talk between the following three mechanisms: 1) suppressing LPS-induced activation of MAP kinases (e.g., ERK1/2, p38, JNK) in a concentration dependent manner; 2) attenuating LPS-induced nuclear translocation of NF-κB p65 subunit in a time dependent manner; 3) activating Nrf2 and subsequently inducing HO-1 expression. HO-1 inhibitor SnPP diminished the inhibitory effects of celastrol on the activation of NF-κB pathway and the pro-inflammatory M1 macrophage polarization. Taken together, celastrol exhibited anti-obesity effects via suppressing pro-inflammatory M1 macrophage polarization. Thus, our results provide new evidence for the potential of celastrol in the treatment of obesity.

The Signaling Pathways Involved in the Antiatherosclerotic Effects Produced by Chinese Herbal Medicines

Cardiovascular diseases (CVDs) are considered to be the predominant cause of death in the world. Chinese herb medicines (CHMs) have been widely used for the treatment of CVDs in Asian countries for thousands of years. One reason of high efficacy of CHMs in treating CVDs is attributed to their inhibition in atherosclerosis (AS) development, a critical contributor to CVDs occurrence. Cumulative studies have demonstrated that CHMs alleviate atherogenesis via mediating pathophysiologic events involved in AS. However, there is deficiency in the summaries regarding antiatherogenic signal pathways regulated by CHMs. In this review, we focus on the signal cascades by which herb medicines and relevant extractives, derivatives, and patents improve proatherogenic processes including endothelium dysfunction, lipid accumulation, and inflammation. We mainly elaborate the CHMs-mediated signaling pathways in endothelial cells, macrophages, and vascular smooth muscle cells of each pathogenic event. Moreover, we briefly describe the other AS-related factors such as thrombosis, autophagy, immune response, and noncoding RNAs and effects of CHMs on them in the way of cascade regulation, which is helpful to further illustrate the molecular mechanisms of AS initiation and progression and discover newly effective agents for AS management.

Celastrol as a pentacyclic triterpenoid with chemopreventive properties

Celastrol is a highly investigated anticancer moiety. It is a pentacyclic triterpenoid, isolated several decades ago with promising role in chemoprevention. Celastrol has been found to target multiple proinflammatory, angiogenic and metastatic proteins. Inhibition of these targets results in significant reduction of cancer growth, survival and metastasis. This review summarizes the varied molecular targets of celastrol along with insight into the various recently published clinical, preclinical and industrial patents (2011-2017).

Protective effects of celastrol against γ irradiation-induced oxidative stress in human umbilical vein endothelial cells

High-dose ionizing radiation can cause harmful effects on the cardiovascular system. Notably, endothelial cells are critical targets in radiation-induced damage. γ radiation exerts its biological effects through the radiolysis of water, which further generates ROS and induces lipid peroxidation and DNA damage. The present study aimed to evaluate the potential protective effects of celastrol against γ radiation-induced oxidative stress in human umbilical vein endothelial cells (HUVECs). HUVECs were exposed to γ radiation at different doses with or without celastrol treatment. Cell viability and cytotoxicity, migratory ability, ROS production, lipid peroxidation, oxidative DNA damage and antioxidative enzyme levels were evaluated in HUVECs at 24 h post-irradiation. It was observed that HUVECs exhibited decreased cell viability, increased cytotoxicity and a decreased migratory ability after exposure to 20-Gy γ radiation. Celastrol treatment concentration-dependently reversed these effects. γ irradiation was also demonstrated to increase the production of ROS, enhance lipid peroxidation and oxidative DNA damage and decrease the levels of SOD, catalase, GST and GPx in HUVECs. These detrimental effects were blocked by treatment with celastrol for 24 h. These data suggested that celastrol not only attenuated γ radiation-induced cytotoxicity, but also effectively blocked oxidative stress in HUVECs. As an antioxidant agent, celastrol may have potential protective effects in HUVECs against γ irradiation-induced injury.

Role of PCSK9 in lipid metabolism and atherosclerosis

Elevated plasma low-density lipoprotein cholesterol (LDL-C) is an important risk factor for cardiovascular diseases. Statins are the most widely used therapy for patients with hyperlipidemia. However, a significant residual cardiovascular risk remains in some patients even after maximally tolerated statin therapy. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a new pharmacologically therapeutic target for decreasing LDL-C. PCSK9 reduces LDL intake from circulation by enhancing LDLR degradation and preventing LDLR recirculation to the cell surface. Moreover, PCSK9 inhibitors have been approved for patients with either familial hypercholesterolemia or atherosclerotic cardiovascular disease, who require additional reduction of LDL-C. In addition, PCSK9 inhibition combined with statins has been used as a new approach to help reduce LDL-C levels in patients with either statin intolerance or unattainable LDL goal. This review will discuss the emerging anti-PCSK9 therapies in the regulation of cholesterol metabolism and atherosclerosis.

Novel Low-Toxic Derivative of Celastrol Maintains Protective Effect against Acute Renal Injury

This study aimed to novelly design and synthesize an amide derivative as a potential substitute of celastrol (CLT). We constituted the compound celastrol-glucosamine (CLG) by conjugating 1-(2-aminoethoxy)-2-glucosamine to celastrol (CLT) and confirmed its chemical structure by ¹H NMR, ¹³C NMR, and LC-MS/MS. Then, the potential efficacy of the CLG was investigated on renal ischemia-reperfusion injury animal models. The results demonstrated that the decorated compound CLG could completely reverse the disease progression as same as CLT. Furthermore, the toxicity of CLG was also fully evaluated in rat blood, liver, kidney, heart, spleen, lung, and reproductive system. Compared to the performance of CLT on normal organs, CLG could remarkably maintain high safety and significantly reduce the side effects. Taken together, the CLG could keep the same efficacy as CLT while processing lower toxicity in vivo.

miR-33a-5p enhances the sensitivity of lung adenocarcinoma cells to celastrol by regulating mTOR signaling

MicroRNAs (miRNAs or miRs) have recently become a popular focus of cancer research due to their ability to act as oncogenes or tumor suppressors. In the present study, miR‑33a‑5p expression was identified to be downregulated in lung adenocarcinoma samples compared with normal, which suggested that miR‑33a‑5p may serve as a tumor suppressor gene. Transfection with miR‑33a‑5p mimics inhibited the proliferation and migration of A549 and LTEP‑a‑2 cells and increased cellular apoptosis. A luciferase reporter assay confirmed that miR‑33a‑5p targets the 3'‑untranslated region of the mechanistic target of rapamycin (mTOR) gene. mTOR expression was decreased in A549 and LTEP‑a‑2 cells treated with miR‑33a‑5p mimics, as well as the expression of its downstream effectors phosphorylated (p)‑p70 ribosomal protein S6 kinase (p70S6K) and p‑eukaryotic translation initiation factor 4E binding protein 1 (4EBP1). Following treatment with celastrol, miR‑33a‑5p expression was upregulated, and miR‑33a‑5p could enhance cellular sensitivity to celastrol. Western blot analysis revealed that the expression of mTOR, p‑p70S6K and p‑4EBP1 decreased following celastrol treatment. These results suggested that mTOR was involved in the mechanism by which miR‑33a‑5p enhanced the sensitivity of lung adenocarcinoma cells to celastrol. Furthermore, LTEP‑a‑2 cells were xenografted subcutaneously into nude mice, to examine the effect of celastrol and miR‑33a‑5p on the growth of LTEP‑a‑2 cells in vivo. The results demonstrated that tumor growth in the celastrol‑treated or miR‑33a‑5p‑treated group was attenuated compared with the control group. Notably, tumor growth in the combination treatment group was almost arrested after 2 weeks. In addition, celastrol upregulated the expression of miR‑33a‑5p, and high expression of miR‑33a‑5p inhibited mTOR and its downstream effectors. In summary, miR‑33a‑5p inhibited the proliferation of lung adenocarcinoma cells, enhanced the antitumor effect of celastrol, and improved sensitivity to celastrol by targeting mTOR in lung adenocarcinoma in vitro and in vivo.

A Mechanistic Overview of Triptolide and Celastrol, Natural Products from Tripterygium wilfordii Hook F

Triptolide and celastrol are predominantly active natural products isolated from the medicinal plant Tripterygium wilfordii Hook F. These compounds exhibit similar pharmacological activities, including anti-cancer, anti-inflammation, anti-obesity, and anti-diabetic activities. Triptolide and celastrol also provide neuroprotection and prevent cardiovascular and metabolic diseases. However, toxicity restricts the further development of triptolide and celastrol. In this review, we comprehensively review therapeutic targets and mechanisms of action, and translational study of triptolide and celastrol. We systemically discuss the structure-activity-relationship of triptolide, celastrol, and their derivatives. Furthermore, we propose the use of structural derivatives, targeted therapy, and combination treatment as possible solutions to reduce toxicity and increase therapeutic window of these potent natural products from T. wilfordii Hook F.

Novel Insights in Systemic Lupus Erythematosus and Atherosclerosis

Introduction

The systemic inflammatory nature of systemic lupus erythematosus (SLE) is well patent not only in the diverse clinical manifestations of the disease but also in the increased risk of premature atherosclerosis and cardiovascular events (CVE), making SLE one of the most complex diseases to study and manage in clinical practice.

Aim

To travel from old aspects to modern insights on the physiopathology, new molecular biomarkers, imaging methods of atherosclerosis assessment, and the potential treatments of atherosclerosis in SLE.

Methods

We conducted a literature search using PubMed database and performed a critical review.

Conclusion/discussion

Several developments have taken place in the understanding of the relationship between SLE and premature atherosclerosis. Nevertheless, cardiovascular diseases are still the major cause of reduced life expectancy in SLE and the main cause of death. The lack of standardization methods for the imaging assessment of atherosclerosis in SLE and the multifactorial nature of the disease are well patriated in the difficulty of achieving consistent and reproducible results among studies that focus in cardiovascular risk assessment and prediction. A raising number of molecular biomarkers of atherosclerosis have been proposed, but the combination of several biomarkers and risk factors may better estimate cardiovascular disease risk. Moreover, the development of effective therapies to prevent progression of atherosclerosis and CVE shall address systemic inflammation.

Tripterine alleviates lipopolysaccharide-induced airway epithelial barrier dysfunction through suppressing the Hippo pathway

Recent studies show that airway epithelial barrier dysfunction is closely associated with allergic inflammation and asthma pathogenesis.