Celastrol and Its Role in Controlling Chronic Diseases

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.

Celastrol ameliorates hypoxic-ischemic brain injury in neonatal rats by reducing oxidative stress and inflammation

BACKGROUND

Hypoxic-ischemic encephalopathy (HIE) is caused by perinatal hypoxia and subsequent reductions in cerebral blood flow and is one of the leading causes of severe disability or death in newborns. Despite its prevalence, we currently lack an effective drug therapy to combat HIE. Celastrol (Cel) is a pentacyclic triterpene extracted from Tripterygium Wilfordi that can protect against oxidative stress, inflammation, and cancer. However, whether Cel can alleviate neonatal hypoxic-ischemic (HI) brain damage remains unclear.

METHODS

Here, we established both in vitro and in vivo models of HI brain damage using CoCl2-treated PC12 cells and neonatal rats, respectively, and explored the neuroprotective effects of Cel in these models.

RESULTS

Analyses revealed that Cel administration reduced brain infarction size, microglia activation, levels of inflammation factors, and levels of oxidative stress markers by upregulating levels of p-AMPKα, Nrf2, HO-1, and by downregulating levels of TXNIP and NLRP3. Conversely, these beneficial effects of Cel on HI brain damage were largely inhibited by AMPKα inhibitor Compound C and its siRNA.

CONCLUSIONS

We present compelling evidence that Cel decreases inflammation and oxidative stress through the AMPKα/Nrf2/TXNIP signaling pathway, thereby alleviating neonatal HI brain injury. Cel therefore represents a promising therapeutic agent for treating HIE.

IMPACT

We firstly report that celastrol can ameliorate neonatal hypoxic-ischemic brain injury both in in vivo and in vitro, which represents a promising therapeutic agent for treating related brain injuries. Celastrol activates the AMPKα/Nrf2/TXNIP signaling pathway to relieve oxidative stress and inflammation and thereby alleviates neonatal hypoxic-ischemic brain injury.

Recent Approaches for the Topical Treatment of Psoriasis Using Nanoparticles

Psoriasis (PSO) is a chronic autoimmune skin condition characterized by the rapid and excessive growth of skin cells, which leads to the formation of thick, red, and scaly patches on the surface of the skin. These patches can be itchy and painful, and they may cause discomfort for patients affected by this condition. Therapies for psoriasis aim to alleviate symptoms, reduce inflammation, and slow down the excessive skin cell growth. Conventional topical treatment options are non-specific, have low efficacy and are associated with adverse effects, which is why researchers are investigating different delivery mechanisms. A novel approach to drug delivery using nanoparticles (NPs) shows promise in reducing toxicity and improving therapeutic efficacy. The unique properties of NPs, such as their small size and large surface area, make them attractive for targeted drug delivery, enhanced drug stability, and controlled release. In the context of PSO, NPs can be designed to deliver active ingredients with anti-inflammatory effect, immunosuppressants, or other therapeutic compounds directly to affected skin areas. These novel formulations offer improved access to the epidermis and facilitate better absorption, thus enhancing the therapeutic efficacy of conventional anti-psoriatic drugs. NPs increase the surface-to-volume ratio, resulting in enhanced penetration through the skin, including intracellular, intercellular, and trans-appendage routes. The present review aims to discuss the latest approaches for the topical therapy of PSO using NPs. It is intended to summarize the results of the in vitro and in vivo examinations carried out in the last few years regarding the effectiveness and safety of nanoparticles.

Deciphering aging-associated molecular mechanisms in bone marrow derived hematopoietic stem cells in the elderly using NGS data

Aging is a complex process that is not yet fully understood. Despite advancements in research, a deeper understanding of the underlying biological mechanisms is necessary to develop interventions that promote healthy longevity. The aim of this study was to elucidate the complex mechanisms associated with healthy aging and longevity in healthy elderly individuals. The RNA sequencing (RNA-seq) data used in this study was obtained from the Gene Expression Omnibus (GEO) database (accession number GSE104406), which was collected from Fluorescent Activated Cell Sorting (FACS) of human bone marrow derived human hematopoietic stem cells (BM-HSCs) (Lineage-, CD34+, CD38-) young (18-30 years old) and aged (65-75 years old) donors who had no known hematological malignancy, with 10 biological replicates per group. The GEO RNA-seq Experiments Interactive Navigator (GREIN) software was used to obtain raw gene-level counts and filtered metadata for this dataset. Next generation knowledge discovery (NGKD) tools provided by BioJupies were used to obtain differentially regulated pathways, gene ontologies (GO), and gene signatures in the BM-HSCs. Finally, the L1000 Characteristic Direction Signature Search Engine (L1000CDS2) tool was used to identify specific drugs that reverse aging-associated gene signatures in old but healthy individuals. The down-regulation of signaling pathways such as longevity regulation, proteasome, Notch, apoptosis, nuclear factor kappa B (NFkB), and peroxisome proliferator-activated receptors (PPAR) signaling pathways in the BM-HSCs of healthy elderly. GO functions related to negative regulation of bone morphogenetic protein (BMP), telomeric DNA binding, nucleoside binding, calcium -dependent protein binding, chromatin-DNA binding, SMAD binding, and demethylase activity were significantly downregulated in the BM-HSCs of the elderly compared to the healthy young group. Importantly, potential drugs such as salermide, celestrol, cercosporin, dorsomorphin dihydrochloride, and LDN-193189 monohydrochloride that can reverse the aging-associated signatures in HSCs from healthy elderly were identified. The analysis of RNA-seq data based on NGKD techniques revealed a plethora of differentially regulated pathways, gene ontologies, and drugs with anti-aging potential to promote healthspan in the elderly.

Recent advances in drug delivery of celastrol for enhancing efficiency and reducing the toxicity

Celastrol is a quinone methyl triterpenoid monomeric ingredient extracted from the root of Tripterygium wilfordii. Celastrol shows potential pharmacological activities in various diseases, which include inflammatory, obesity, cancer, and bacterial diseases. However, the application prospect of celastrol is largely limited by its low bioavailability, poor water solubility, and undesired off-target cytotoxicity. To address these problems, a number of drug delivery methods and technologies have been reported to enhance the efficiency and reduce the toxicity of celastrol. We classified the current drug delivery technologies into two parts. The direct chemical modification includes nucleic acid aptamer-celastrol conjugate, nucleic acid aptamer-dendrimer-celastrol conjugate, and glucolipid-celastrol conjugate. The indirect modification includes dendrimers, polymers, albumins, and vesicular carriers. The current technologies can covalently bond or encapsulate celastrol, which improves its selectivity. Here, we present a review that focalizes the recent advances of drug delivery strategies in enhancing the efficiency and reducing the toxicity of celastrol.

Celastrol inhibits platelet function and thrombus formation

INTRODUCTION

Celastrol is an active pentacyclic triterpenoid extracted from Tripterygium wilfordii and has anti-inflammatory and anti-tumor properties. Whether Celastrol modulates platelet function remains unknown. Our study investigated its role in platelet function and thrombosis.

METHODS

Human platelets were isolated and incubated with Celastrol (0, 1, 3 and 5 μM) at 37 °C for 1 h to measure platelet aggregation, granules release, spreading, thrombin-induced clot retraction and intracellular calcium mobilization. Additionally, Celastrol (2 mg/kg) was intraperitoneally administrated into mice to evaluate hemostasis and thrombosis in vivo.

RESULTS

Celastrol treatment significantly decreased platelet aggregation and secretion of dense or alpha granules induced by collagen-related peptide (CRP) or thrombin in a dose-dependent manner. Additionally, Celastrol-treated platelets showed a dramatically reduced spreading activity and decreased clot retraction. Moreover, Celastrol administration prolonged tail bleeding time and inhibited formation of arterial/venous thrombosis. Furthermore, Celastrol significantly reduced calcium mobilization.

CONCLUSION

Celastrol inhibits platelet function and venous/arterial thrombosis, implying that it might be utilized for treating thrombotic diseases.

Tripterine Inhibits Proliferation and Promotes Apoptosis of Keloid Fibroblasts by Targeting ROS/JNK Signaling

Keloids are benign skin tumors characterized by excessive fibroblast proliferation and collagen deposition. The current treatment of keloids with hormone drug injection, surgical excision, radiotherapy, physical compression, laser therapy, cryotherapy often have unsatisfactory outcomes. The phytochemical compounds have shown great potential in treating keloids. Tripterine, a natural triterpene derived from the traditional Chinese medicine Thunder God Vine (Tripterygium wilfordii), was previously reported to exhibit an anti-scarring bioactivity in mouse embryonic fibroblast NIH/3T3 cells. Accordingly, our study was dedicated to explore its role in regulating the pathological phenotypes of keloid fibroblasts. Human keloid fibroblasts were treated with tripterine (0-10 μM) for 24 hours. Cell viability, proliferation, migration, apoptosis, and extracellular matrix (ECM) deposition were determined by CCK-8, EdU, wound healing, Transwell, flow cytometry, western blotting, and RT-qPCR assays. The effects of tripterine treatment on reactive oxygen species (ROS) generation and JNK activation in keloid fibroblasts were assessed by DCFH-DA staining and western blotting analysis. Tripterine at the concentrations higher than 4 μM attenuated the viability of human keloid fibroblasts in a dose-dependent manner. Treatment with tripterine (4, 6, and 8 μM) dose-dependently inhibited cell proliferation and migration, promoted cell apoptosis, reduced α-SMA, Col1, and Fn expression, induced ROS production, and enhanced JNK phosphorylation in keloid fibroblasts. Collectively, tripterine ameliorates the pathological characteristics of keloid fibroblasts that are associated with keloidformation and growth by inducing ROS generation and activating JNK signalingpathway.

Toxic metabolites and metabolic soft spots of celastrol based on glutathione metabolic capture and high-resolution mass spectrometry

BACKGROUND

Celastrol is known as one of the most medicinally valuable compounds. However, the pharmaceutical application of celastrol is significantly limited due to high toxicity, while there are few reports on the mechanism of toxicity.

METHODS

This study searched for possible toxic metabolites through phase I in vitro metabolism and glutathione capture experiments. Then in vivo metabolism experiments in mice and rats were conducted to look for metabolites in vivo. Finally, mice in vivo toxicity experiment was conducted to verify the toxicity of different doses of celastrol to mice.

RESULTS

In the in vivo and in vitro metabolism experiments, we found 7 phase I metabolites in vitro, 9 glutathione conjugation metabolites in vitro, and 20 metabolites in vivo. The metabolic soft points of celastrol could be the quinone methyl structure at C3-OH and C6. In vivo toxicity experiments show that celastrol causes weight loss, diarrhea, gastrointestinal tract and liver inflammation in mice.

CONCLUSIONS

This study analyzed the metabolites and possible metabolic soft spots of celastrol, and its hepatotoxicity and gastrointestinal toxicity were demonstrated through in vivo studies for the first time. The results might provide an important basis for potential structural modification to increase the druggability of celastrol.

Celastrol attenuates streptozotocin-induced diabetic cardiomyopathy in mice by inhibiting the ACE / Ang II / AGTR1 signaling pathway

BACKGROUND

Heart failure is closely correlated with diabetic cardiomyopathy (DCM) and can lead to mortality. Celastrol has long been utilized for the treatment of immune and inflammatory disorders. However, whether celastrol would exert protective effects on DCM has not been determined. This work aimed to explore the protective actions of celastrol on DCM and unravel the underlying mechanisms involved.

METHODS

A DCM model was constructed in mice by intraperitoneal administration of streptozotocin. ELISA and echocardiography were performed to examine myocardial injury markers and cardiac function, respectively. Morphological changes and fibrosis were assessed using H&E staining and Masson's staining. Inflammatory cytokines and fibrotic markers were detected by ELISA and RT-PCR. Endothelial nitric oxide synthase, apoptosis, and reactive oxygen species were detected by microscopic staining. Network pharmacology approaches, molecular docking analysis, ELISA, and Western blot were used for mechanism studies.

RESULTS

Celastrol alleviated diabetes-induced cardiac injury and remodeling. Celastrol also suppressed diabetes-induced production of inflammatory cytokines and reactive oxygen species, as well as cardiomyocyte apoptosis. The cardioprotective effects of celastrol were associated with its inhibition on the angiotensin-converting enzyme / angiotensin II / angiotensin II receptor type 1 signaling pathway.

CONCLUSION

Celastrol exhibits significant potential as an effective cardioprotective drug for DCM treatment. The underlying mechanisms can be attributed to the blockage of celastrol on the angiotensin-converting enzyme signaling pathway.

Tripterygium wilfordii derivative celastrol, a YAP inhibitor, has antifibrotic effects in systemic sclerosis

OBJECTIVES

Systemic sclerosis (SSc) is characterised by extensive tissue fibrosis maintained by mechanotranductive/proadhesive signalling. Drugs targeting this pathway are therefore of likely therapeutic benefit. The mechanosensitive transcriptional co-activator, yes activated protein-1 (YAP1), is activated in SSc fibroblasts. The terpenoid celastrol is a YAP1 inhibitor; however, if celastrol can alleviate SSc fibrosis is unknown. Moreover, the cell niches required for skin fibrosis are unknown.

METHODS

Human dermal fibroblasts from healthy individuals and patients with diffuse cutaneous SSc were treated with or without transforming growth factor β1 (TGFβ1), with or without celastrol. Mice were subjected to the bleomycin-induced model of skin SSc, in the presence or absence of celastrol. Fibrosis was assessed using RNA Sequencing, real-time PCR, spatial transcriptomic analyses, Western blot, ELISA and histological analyses.

RESULTS

In dermal fibroblasts, celastrol impaired the ability of TGFβ1 to induce an SSc-like pattern of gene expression, including that of cellular communication network factor 2, collagen I and TGFβ1. Celastrol alleviated the persistent fibrotic phenotype of dermal fibroblasts cultured from lesions of SSc patients. In the bleomycin-induced model of skin SSc, increased expression of genes associated with reticular fibroblast and hippo/YAP clusters was observed; conversely, celastrol inhibited these bleomycin-induced changes and blocked nuclear localisation of YAP.

CONCLUSIONS

Our data clarify niches within the skin activated in fibrosis and suggest that compounds, such as celastrol, that antagonise the YAP pathway may be potential treatments for SSc skin fibrosis.

The Promising Therapeutic Potential of Celastrol for Fibrotic Diseases: A Systematic Literature Review on Its Mechanism

Celastrol is a pentacyclic tripterine sourced from Tripterygium wilfordii hook root. Celastrol can exert certain biological functions such as antitumor, anti-inflammatory, and antiproliferative properties. Celastrol was shown from the previous literature to be capable of attenuating many fibrotic diseases. As the effects of various fibrotic diseases such as atherosclerosis, cancer, and ischemia affect more people with devastating repercussions, this warrants celastrol to be exploited as a phytotherapeutic drug. The purpose of this study is to review previous research and identify the proposed therapeutic mechanisms of celastrol in fibrotic diseases focusing on both the in vitro and in vivo experimental models.  A systematic literature search on Web of Science (WoS), Scopus, and ScienceDirect that included articles published between 2012 and 2022 was carried out using the keywords "celastrol", "tripterine", "fibrotic disease", and "fibrosis". After screening the initial search yield of 405 articles, 25 articles were included in this review.  The study findings summarize the potential therapeutic mechanism of celastrol in the attenuation of fibrotic diseases in in vivo and in vitro experimental models. It shows that celastrol is useful as a treatment means. However, more studies are needed on the effects of celastrol on humans to carry out clinical trials to verify the long-term benefits of celastrol.

Celastrol relieves myocardial infarction-induced cardiac fibrosis by inhibiting NLRP3 inflammasomes in rats

BACKGROUND

Myocardial infarction (MI) triggers a strong inflammatory response mediating by NLRP3 inflammasome which is associated with cardiac fibrosis. The key players in this response are Interleukin (IL)-1 and IL-18, which are regulated by NLRP3 inflammasomes. Celastrol, a traditional Chinese medicine with strong anti-inflammatory activity, has recently reported as a cardioprotective agent. However, the mechanisms by which celastrol is cardioprotective in MI remain elusive. We hypothesized that Celastrol could reduce IL-1β and IL-18 expression and ameliorate myocardial fibrosis after myocardial infarction in rats, improve poor heart remodeling, and preserve heart function.

METHODS

Myocardial infarction (MI) was caused by ligating the left anterior descending of male SD rats. Celastrol (1 mg/kg) or saline was administered every other day for 4 weeks. Heart function and fibrosis were assessed. Inflammatory and fibrotic markers in the myocardia were evaluated with immunohistochemistry, western blot, and ELISA. Molecular docking was employed to predict Celastrol's binding to NLRP3 protein. The effects of Celastrol on the expression of NLRP3 inflammasome and myocardial fibrosis genes were then examined in vitro.

RESULTS

Celastrol maintained the left ventricular fractional shortening (FS) and ejection fraction (EF). Fibrosis was significantly reduced in animals treated with 1 mg/kg Celastrol (15.17 ± 1.82%) relative to controls (29.88 ± 4.28%). Celastrol also significantly reduced the NLRP3, IL-18, and IL-1β levels, together with macrophage and neutrophil infiltration in the myocardium. Molecular docking predicted that NLRP3 would bind tightly to Celastrol [Docking energy: -8.9 (kcal/mol)]. In vitro experiments showed reduced NLRP3 inflammasome and myocardial fibrosis-associated proteins expression in neonatal rat cardiac fibroblasts treated with Celastrol.

CONCLUSIONS

In post-MI rats, Celastrol, a naturally occurring active ingredient, was able to reduce myocardial fibrosis and improve cardiac function, according to our study. These effects may result from inhibiting the NLRP3 inflammasome and attenuating the early inflammatory storm after MI, suggesting that Celastrol may be useful in treating acute MI.

Mechanisms of and Potential Medications for Oxidative Stress in Ovarian Granulosa Cells: A Review

Granulosa cells are essential for follicle initiation and development, and their abnormal function or apoptosis is a crucial factor leading to follicular atresia. A state of oxidative stress occurs when the balance between the production of reactive oxygen species and the regulation of the antioxidant system is disturbed. Oxidative stress is one of the most important causes of the abnormal function and apoptosis of granulosa cells. Oxidative stress in granulosa cells causes female reproductive system diseases, such as polycystic ovary syndrome and premature ovarian failure. In recent years, studies have confirmed that the mechanism of oxidative stress in granulosa cells is closely linked to the PI3K-AKT signaling pathway, MAPK signaling pathway, FOXO axis, Nrf2 pathway, NF-κB signaling pathway, and mitophagy. It has been found that drugs such as sulforaphane, Periplaneta americana peptide, and resveratrol can mitigate the functional damage caused by oxidative stress on granulosa cells. This paper reviews some of the mechanisms involved in oxidative stress in granulosa cells and describes the mechanisms underlying the pharmacological treatment of oxidative stress in granulosa cells.

Plant-Based Antioxidants for Prevention and Treatment of Neurodegenerative Diseases: Phytotherapeutic Potential of Laurus nobilis, Aronia melanocarpa, and Celastrol

With the progress of medicine, especially in the last century, life expectancy increased considerably. As a result, age-related diseases also increased, especially malignancies and degenerative diseases of the central nervous system. The incidence and prevalence of neurodegenerative diseases steadily increased over the years, but despite efforts to uncover the pathophysiological processes behind these conditions, they remain elusive. Among the many theories, oxidative stress was proposed to be involved in neurodegenerative processes and to play an important role in the morbidity and progression of various neurodegenerative disorders. Accordingly, a number of studies discovered the potential of natural plant constituents to have significant antioxidant activity. This review focused on several plant-based antioxidants that showed promising results in the prevention and treatment of neurodegenerative diseases. Laurus nobilis, Aronia melanocarpa, and celastrol, a chemical compound isolated from the root extracts of Tripterygium wilfordii and T. regelii, are all known to be rich in antioxidant polyphenols.

Celastrol confers ferroptosis resistance via AKT/GSK3β signaling in high-fat diet-induced cardiac injury

Obesity-induced cardiac dysfunction is a severe global disease associated with high dietary fat intake, and its pathogenesis includes inflammation, oxidative stress, and ferroptosis. Celastrol (Cel) is a bioactive compound isolated from the herb Tripterygium wilfordii, which has a protective influence on cardiovascular diseases. In this study, the role of Cel in obesity-induced ferroptosis and cardiac injury was investigated. We found that Cel alleviated ferroptosis induced by Palmitic acid (PA), exhibiting a decrease in the LDH, CK-MB, Ptgs2, and Lipid Peroxidation levels. After cardiomyocytes were treated with additional LY294002 and LiCl, Cel exerted its protective effect through increased AKT/GSK3β phosphorylation and decreased level of lipid peroxidation and Mitochondrial ROS. The systolic left ventricle (LV) dysfunction of obese mice was alleviated via ferroptosis inhibition by elevated p-GSK3β and decreased Mitochondrial ROS under Cel treatment. Moreover, mitochondrial anomalies included swelling and distortion in the myocardium which was relieved with Cel. In conclusion, our results demonstrate that ferroptosis resistance with Cel under HFD conditions targets AKT/GSK3β signaling, which provides novel therapeutic strategies in obesity-induced cardiac injury.

Myrtus communis and Celastrol enriched plant cell culture extracts control together the pivotal role of Cutibacterium acnes and inflammatory pathways in acne

INTRODUCTION

Acne is a multifactorial inflammatory disease of the pilosebaceous unit in which Cutibacterium acnes is one of the main triggers. A strong predominance of C. acnes phylotype IA1 is present in acne skin with higher biofilm organization and virulence, promoting local immuno-inflammation, especially the Th17 pathway.

OBJECTIVES

We evaluated the single and combined pharmacological properties of the plant extracts, Myrtus communis (Myrtacine®) and Celastrol enriched plant cell culture (CEE) extracts on the C. acnes/Th17 pathway.

METHODS

The effect of Myrtacine® on the virulence of C. acnes phylotype IA1 was quantified according to the expression of several related genes. The activity of Myrtacine® and CEE on the inflammatory cascade was assessed using monocytes-derived dendritic cells (Mo-DC) stimulated with membranes or biofilms of the C. acnes phylotype IA1. Finally, the effect of CEE on the Th17 pathway was studied using C. acnes stimulated sebocyte 2D cultures and 3D skin tissue models containing preactivated Th17 cells.

RESULTS

Myrtacine® had an anti-virulence effect, evident as a significant and strong inhibition of the expression of several virulence factor genes by 60%-95% compared to untreated controls. Myrtacine® and CEE significantly inhibited proinflammatory cytokine (IL-6, IL-8, IL-12p40 and TNF-α) production by Mo-DC in response to C. acnes phylotype IA1. Interestingly, these two ingredients resulted in synergistic inhibition of most cytokines when used in combination. Finally, we demonstrated an inhibitory effect of CEE, in solution or formulated at 0.3%, specifically on IL-17 release by Th17 lymphocytes in a C. acnes-stimulated sebocyte 2D cultures and by Th17-lymphocytes integrated in a 3D skin models.

CONCLUSIONS

2D and 3D models were developed to represent relevant and specific pathways involved in acne. Myrtacine® and CEE were shown to alter one or more of these pathways, indicating their potential beneficial effects on this disease.

Lipopolysaccharide Activating NF-kB Signaling by Regulates HTRA1 Expression in Human Retinal Pigment Epithelial Cells

Inflammation and elevated expression of high temperature requirement A serine peptidase 1 (HTRA1) are known high risk factors for age-related macular degeneration (AMD). However, the specific mechanism that HTRA1 causes AMD and the relationship between HTRA1 and inflammation remains unclear. We found that lipopolysaccharide (LPS) induced inflammation enhanced the expression of HTRA1, NF-κB, and p-p65 in ARPE-19 cells. Overexpression of HTRA1 up-regulated NF-κB expression, and on the other hand knockdown of HTRA1 down-regulated the expression of NF-κB. Moreover, NF-κB siRNA has no significant effect on the expression of HTRA1, suggesting HTRA1 works upstream of NF-κB. These results demonstrated that HTRA1 plays a pivotal role in inflammation, explaining possible mechanism of overexpressed HTRA1-induced AMD. Celastrol, a very common anti-inflammatory and antioxidant drug, was found to suppress inflammation by inhibiting phosphorylation of p65 protein efficaciously in RPE cells, which may be applied to the therapy of age-related macular degeneration.

Spatial transcriptomics analysis of zone-dependent hepatic ischemia-reperfusion injury murine model

Hepatic ischemia-reperfusion (I/R) injury is a common complication in liver transplantation. The connection between I/R-induced injury response and liver heterogeneity has yet to be fully understood. In this study, we converge histopathological examination with spatial transcriptomics to dissect I/R injury patterns and their associated molecular changes, which reveal that the pericentral zones are most sensitive to I/R injury in terms of histology, transcriptomic changes, and cell type dynamics. Bioinformatic analysis of I/R injury-related pathways predicts that celastrol can protect against liver I/R injury by inducing ischemic pre-conditioning, which is experimentally validated. Mechanistically, celastrol likely implements its protective effect against I/R injury by activating HIF1α signaling and represents a potential strategy for resolving liver I/R.

Natural Bioactive Compounds Targeting NADPH Oxidase Pathway in Cardiovascular Diseases

Cardiovascular disease (CVD) is the leading cause of death worldwide, in both developed and developing countries. According to the WHO report, the morbidity and mortality caused by CVD will continue to rise with the estimation of death going up to 22.2 million in 2030. NADPH oxidase (NOX)-derived reactive oxygen species (ROS) production induces endothelial nitric oxide synthase (eNOS) uncoupling and mitochondrial dysfunction, resulting in sustained oxidative stress and the development of cardiovascular diseases. Seven distinct members of the family have been identified of which four (namely, NOX1, 2, 4 and 5) may have cardiovascular functions. Currently, the treatment and management plan for patients with CVDs mainly depends on the drugs. However, prolonged use of prescribed drugs may cause adverse drug reactions. Therefore, it is crucial to find alternative treatment options with lesser adverse effects. Natural products have been gaining interest as complementary therapy for CVDs over the past decade due to their wide range of medicinal properties, including antioxidants. These might be due to their potent active ingredients, such as flavonoid and phenolic compounds. Numerous natural compounds have been demonstrated to have advantageous effects on cardiovascular disease via NADPH cascade. This review highlights the potential of natural products targeting NOX-derived ROS generation in treating CVDs. Emphasis is put on the activation of the oxidases, including upstream or downstream signalling events.

Chinese medicinal herbs as potential prodrugs for obesity

Obesity is a leading worldwide health threat with ever-growing prevalence, it promotes the incidence of various diseases, particularly cardiovascular disease, metabolic syndrome, diabetes, hypertension, and certain cancers. Traditional Chinese Medicine (TCM) has been used to control body weight and treat obesity for thousands of years, Chinese medicinal herbs provide a rich natural source of effective agents against obesity. However, some problems such as complex active ingredients, poor quality control, and unclear therapeutic mechanisms still need to be investigated and resolved. Prodrugs provide a path forward to overcome TCM deficiencies such as absorption, distribution, metabolism, excretion (ADME) properties, and toxicity. This article aimed to review the possible prodrugs from various medicinal plants that demonstrate beneficial effects on obesity and seek to offer insights on prodrug design as well as a solution to the global obesity issues.

Psoriasis and neurodegenerative diseases—a review

Psoriasis is a chronic skin disease with underlying genetic, inflammatory and immunological background, which is a great medical problem, currently regarded as a systemic condition. Neurodegenerative diseases (NDs) are characterized by a progressive loss of nervous tissue, which affects elderly people more frequently; therefore, it is suspected that, due to society's aging, morbidity is going to increase. We performed a thorough review in order to investigate for the first time whether psoriasis may predispose to different particular neurodegenerative diseases—Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS). PubMed search resulted in the retrieval of 833 records, of which 77 eligible were included in the review. Our thorough analysis revealed there are some potential links between psoriasis and NDs (inflammation, oxidative stress, genetics, cardiometabolic disorders), but there is no strong evidence that psoriasis may predispose to NDs. Based on the evidence, it seems that the risk of PD in psoriatics is not increased, and the evidence for increased risk of AD slightly prevails the data that state the opposite. ALS risk does not seem to be increased in psoriatics. The paucity of original studies does not allow for the formulation of definitive conclusions but encourages to perform further investigations.

An Emerging Role of Proanthocyanidins on Psoriasis: Evidence from a Psoriasis-Like Mouse Model

Background

Psoriasis is an immune-mediated, chronic inflammatory disease, and genetic, immune, oxidative stress (OS), and environmental factors are all thought to contribute to its occurrence. Proanthocyanidins (PCs) are natural flavonoids consisting of catechins and epicatechins which have anti-inflammatory and anti-OS activities. PCs have been widely used to treat various diseases, but reports regarding psoriasis are rare.

Objective

To investigate the therapeutic effect and potential mechanisms of action of PCs in a psoriasis-like mouse model.

Methods

Thirty male BALB/c hairless mice were assigned to six groups (n = 5): normal, model, low-dose PCs, medium-dose PCs, high-dose PCs, and control groups. The final five groups were dorsally exposed to 5% imiquimod (IMQ) cream once a day for 6 consecutive days, while the normal group received no intervention. Following the first day of IMQ application, mice in the PC-treated group were dosed with different amounts of PCs daily by oral gavage for six days, whereas mice in the control group received normal saline in the same way. One week later, skin lesions were evaluated by the severity of scoring system based on psoriasis area and severity index (PASI), and pathological alterations were assessed by hematoxylin-eosin (HE) staining. Indicators of inflammation or OS, such as interleukin- (IL-) 17, IL-23, phosphorylated-phosphatidylinositol 3-kinase (p-PI3K), phosphorylated-signal transducer and activator of transcription 3 (p-STAT3), superoxide dismutase (SOD), glutathione (GSH), malondialdehyde (MDA), catalase (CAT), vascular endothelial growth factor (VEGF), inducible nitric oxide synthase (iNOS), reactive oxygen species (ROS), and heme oxygenase-1 (HO-1), were determined by ELISA, RT-PCR, western blot, and immunohistochemistry (IHC) analysis.

Results

IMQ administration induced the formation of large dark red plaques with thickly layered scales on the dorsal skin of mice; nevertheless, the lesions were substantially alleviated by PC administration. Histopathological alterations were observed in both model and control groups with epidermal hyperkeratosis, granulosa layer thinning, acanthosis, downward extension of rete ridges, dermal papillae expansion, capillary hyperplasia, and infiltration by inflammatory cells around blood vessels. These pathological changes, however, were restored by a range of doses of PCs, high-dose PCs in particular. Different doses of PCs significantly lowered the spleen index, levels of inflammatory or oxidative proteins (IL-17, IL-23, MDA, ROS, p-PI3K, and p-STAT3), and the mRNA expression of Il-17, Il-23, Vegf, and iNos. Protein and mRNA levels of anti-OS and anti-inflammatory biomarkers, including SOD, CAT, GSH, and HO-1, greatly increased after PC treatment, especially at the highest dose.

Conclusions

Our findings reveal that PCs ameliorate psoriasis-like symptoms, suppressing the inflammatory response and mitigating OS damage in an IMQ-induced psoriasis-like mouse model. These effects are probably related to the inactivation of STAT3 and PI3K and activation of HO-1 signaling.

Anti-Inflammatory Effects of (3S)-Vestitol on Peritoneal Macrophages

The isoflavone (3S)-vestitol, obtained from red propolis, has exhibited anti-inflammatory, antimicrobial, and anti-caries activity; however, few manuscripts deal with its anti-inflammatory mechanisms in macrophages. The objective is to elucidate the anti-inflammatory mechanisms of (3S)-vestitol on those cells. Peritoneal macrophages of C57BL6 mice, stimulated with lipopolysaccharide, were treated with 0.37 to 0.59 µM of (3S)-vestitol for 48 h. Then, nitric oxide (NO) quantities, macrophages viability, the release of 20 cytokines and the transcription of several genes related to cytokine production and inflammatory response were evaluated. The Tukey–Kramer variance analysis test statistically analyzed the data. (3S)-vestitol 0.55 µM (V55) lowered NO release by 60% without altering cell viability and diminished IL-1β, IL-1α, G-CSF, IL-10 and GM-CSF levels. V55 reduced expression of Icam-1, Wnt5a and Mmp7 (associated to inflammation and tissue destruction in periodontitis) and Scd1, Scd2, Egf1 (correlated to atherosclerosis). V55 increased expression of Socs3 and Dab2 genes (inhibitors of cytokine signaling and NF-κB pathway), Apoe (associated to atherosclerosis control), Igf1 (encoder a protein with analogous effects to insulin) and Fgf10 (fibroblasts growth factor). (3S)-vestitol anti-inflammatory mechanisms involve cytokines and NF-κB pathway inhibition. Moreover, (3S)-vestitol may be a candidate for future in vivo investigations about the treatment/prevention of persistent inflammatory diseases such as atherosclerosis and periodontitis.

Combining bioinformatics, network pharmacology and artificial intelligence to predict the mechanism of celastrol in the treatment of type 2 diabetes

BACKGROUND

Type 2 diabetes (T2D) is a common chronic disease with many serious complications. Celastrol can prevent and treat type 2 diabetes by reversing insulin resistance in a number of ways. However, the specific mechanisms by which celastrol prevents and treats T2D are not well understood. The aim of this study was to explore the key gene targets and potential signaling pathway mechanisms of celastrol for the treatment of T2D.

METHODS

GSE184050 was downloaded from the Gene Expression Omnibus online database. Blood samples from patients and healthy individuals with T2D were analyzed to identify differentially expressed genes (DEGs), and a protein-protein interaction network (PPI) was constructed. Key gene analysis of DEGs was performed using the MCODE plugin in Cystoscope as well as the Hubba plugin, and intersections were taken to obtain hub genes, which were displayed using a Venn diagram. Enrichment analysis was then performed via the ClueGo plugin in Cytoscape and validated using Gene Set Enrichment Analysis. The therapeutic targets of celastrol were then analyzed by pharmacophore network pharmacology, intersected to identify the therapeutic targets of celastrol, enriched for all targets, and intersected to obtain the signaling pathways for celastrol treatment. The protein structures of the therapeutic targets were predicted using the artificial intelligence AlphaFold2. Finally, molecular docking was used to verify whether celastrol could be successfully docked to the predicted targets.

RESULTS

618 DEGs were obtained, and 9 hub genes for T2D were identified by the MCODE and Hubba plug-ins, including ADAMTS15, ADAMTS7, ADAMTSL1, SEMA5B, ADAMTS8, THBS2, HBB, HBD and HBG2. The DEG-enriched signaling pathways mainly included the ferroptosis and TGF-beta signaling pathways. A total of 228 target genes were annotated by pharmacophore target analysis, and the therapeutic targets were identified, including S100A11, RBP3, HBB, BMP7 and IQUB, and 9 therapeutic signaling pathways were obtained by an intersectional set. The protein structures of the therapeutic targets were successfully predicted by AlphaFold2, and docking was validated using molecular docking.

CONCLUSION

Celastrol may prevent and treat T2D through key target genes, such as HBB, as well as signaling pathways, such as the TGF-beta signaling pathway and type II diabetes mellitus.

Targeted delivery of celastrol to glomerular endothelium and podocytes for chronic kidney disease treatment

The etiology of chronic kidney disease (CKD) is complex and diverse, which could be briefly categorized to glomerular- or tubular-originated. However, the final outcomes of CKD are mainly glomerular sclerosis, endothelial dysfunction and injury, and chronic inflammation. Thus, targeted delivery of drugs to the glomeruli in order to ameliorate glomerular endothelial damage may help alleviate CKD and help enrich our knowledge. The herb tripterygium wilfordii shows therapeutic effect on kidney disease, and celastrol (CLT) is one of its active ingredients but with strong toxicity. Therefore, based on the unique structure and pathological characteristics of the glomerulus, we designed a targeted delivery system named peptides coupled CLT-phospholipid lipid nanoparticles (PC-PLNs) to efficiently deliver CLT to damaged endothelial cells and podocytes in the glomerulus for CKD treatment and research. PC-PLNs could effectively inhibit inflammation, reduce endothelial damage, alleviate CKD severity, and reduce the toxicity of CLT. We also studied the mechanism of CLT in the treatment of nephropathy and found that CLT can increase the level of NO by increasing eNOS while inhibiting the expression of VCAM-1, thus provides an anti-inflammatory effect. Therefore, our study not only offered an efficient CKD drug formulation for further development, but also provided new medical knowledge about CKD.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary material (attached with all the supporting tables and figures mentioned in this work) is available in the online version of this article at 10.1007/s12274-021-3894-x.

Herbal Nanoformulations for Asthma Treatment

BACKGROUND

In recent decades, the prevalence of asthma has substantially increased worldwide. Advances in phytochemistry and phytopharmacology have clarified the active ingredients and biological activities of medicinal plant products for treating asthma, and the role of herbal therapies in asthma treatment has become increasingly evident. However, most plant extracts have low solubility and poor stability of bioactive components, resulting in low bioavailability and loss of efficacy. Owing to these shortcomings, the clinical use of many herbal extracts is limited.

OBJECTIVE

To summarise and analyse the characteristics of herbal nanoformulations and their application in asthma treatment. The objective of this review article is to address the emerging trends of herbal nanoformulations for an effective treatment for asthma.

METHODS

Various research and review articles from reputed international journals were referred and compiled.

RESULTS

The nano-sized herbal formulations improve the solubility and bioavailability of herbal medicines and contribute to the sustained release of drugs, thus, increasing the therapeutic applications of herbal extracts. The review present different types of herbal nanoformulations, including micelles, nanoparticles, solid lipid nanoparticles, lipid-based liquid crystalline nanoparticles and nanoemulsions, which are potential nanodrugs for asthma treatment.

CONCLUSIONS

Herbal nanoformulations have shown great prospects for treatment of asthma in recent years. More safety and toxicity data are still needed to promote their development and application.

Pharmacological Preconditioning Improves the Viability and Proangiogenic Paracrine Function of Hydrogel-Encapsulated Mesenchymal Stromal Cells

The efficacy of cell therapy is limited by low retention and survival of transplanted cells in the target tissues. In this work, we hypothesize that pharmacological preconditioning with celastrol, a natural potent antioxidant, could improve the viability and functions of mesenchymal stromal cells (MSC) encapsulated within an injectable scaffold. Bone marrow MSCs from rat (rMSC) and human (hMSC) origin were preconditioned for 1 hour with celastrol 1 μM or vehicle (DMSO 0.1% v/v), then encapsulated within a chitosan-based thermosensitive hydrogel. Cell viability was compared by alamarBlue and live/dead assay. Paracrine function was studied first by quantifying the proangiogenic growth factors released, followed by assessing scratched HUVEC culture wound closure velocity and proliferation of HUVEC when cocultured with encapsulated hMSC. In vivo, the proangiogenic activity was studied by evaluating the neovessel density around the subcutaneously injected hydrogel after one week in rats. Preconditioning strongly enhanced the viability of rMSC and hMSC compared to vehicle-treated cells, with 90% and 75% survival versus 36% and 58% survival, respectively, after 7 days in complete media and 80% versus 64% survival for hMSC after 4 days in low serum media (p < 0.05). Celastrol-treated cells increased quantities of proangiogenic cytokines compared to vehicle-pretreated cells, with a significant 3.0-fold and 1.8-fold increase of VEGFa and SDF-1α, respectively (p < 0.05). The enhanced paracrine function of preconditioned MSC was demonstrated by accelerated growth and wound closure velocity of injured HUVEC monolayer (p < 0.05) in vitro. Moreover, celastrol-treated cells, but not vehicle-treated cells, led to a significant increase of neovessel density in the peri-implant region after one week in vivo compared to the control (blank hydrogel). These results suggest that combining cell pretreatment with celastrol and encapsulation in hydrogel could potentiate MSC therapy for many diseases, benefiting particularly ischemic diseases.

Gut Microbiome Critically Impacts PCB-induced Changes in Metabolic Fingerprints and the Hepatic Transcriptome in Mice

Polychlorinated biphenyls (PCBs) are ubiquitously detected and have been linked to metabolic diseases. Gut microbiome is recognized as a critical regulator of disease susceptibility; however, little is known how PCBs and gut microbiome interact to modulate hepatic xenobiotic and intermediary metabolism. We hypothesized the gut microbiome regulates PCB-mediated changes in the metabolic fingerprints and hepatic transcriptome. Ninety-day-old female conventional and germ-free mice were orally exposed to the Fox River Mixture (synthetic PCB mixture, 6 or 30 mg/kg) or corn oil (vehicle control, 10 ml/kg), once daily for 3 consecutive days. RNA-seq was conducted in liver, and endogenous metabolites were measured in liver and serum by LC-MS. Prototypical target genes of aryl hydrocarbon receptor, pregnane X receptor, and constitutive androstane receptor were more readily upregulated by PCBs in conventional conditions, indicating PCBs, to the hepatic transcriptome, act partly through the gut microbiome. In a gut microbiome-dependent manner, xenobiotic, and steroid metabolism pathways were upregulated, whereas response to misfolded proteins-related pathways was downregulated by PCBs. At the high PCB dose, NADP, and arginine appear to interact with drug-metabolizing enzymes (ie, Cyp1-3 family), which are highly correlated with Ruminiclostridium and Roseburia, providing a novel explanation of gut-liver interaction from PCB-exposure. Utilizing the Library of Integrated Network-based Cellular Signatures L1000 database, therapeutics targeting anti-inflammatory and endoplasmic reticulum stress pathways are predicted to be remedies that can mitigate PCB toxicity. Our findings demonstrate that habitation of the gut microbiota drives PCB-mediated hepatic responses. Our study adds knowledge of physiological response differences from PCB exposure and considerations for further investigations for gut microbiome-dependent therapeutics.

Celastrol Attenuates RANKL-Induced Osteoclastogenesis in vitro and Reduces Titanium Particle-Induced Osteolysis and Ovariectomy-Induced Bone Loss in vivo

Excessive bone resorption by osteoclasts contributes significantly to osteoclast-related diseases such as periprosthetic osteolysis and osteoporosis. Osteolysis in a titanium particle-induced calvarial model and bone loss in an ovariectomized mice model occurred similarly to those in humans; thus, these models can be used to evaluate potential therapies for aseptic prosthetic loosening and osteoporosis. Celastrol, which is extracted from the seeds of the genus Tripterygium, has been thoroughly investigated for its anti-inflammatory and anti-cancer pharmacological effects. However, the mechanisms involving bone metabolism by which celastrol inhibits osteoclastogenesis are not yet fully understood. We demonstrated that celastrol inhibited the receptor activator of nuclear factor κB ligand-induced osteoclastogenesis and the bone resorptive function of osteoclasts in vitro by inhibiting the activation of transforming growth factor β-activated kinase 1-mediated NF-κB and mitogen-activated protein kinase signaling pathways and downregulating osteoclastogenesis marker-related genes. Furthermore, celastrol was also shown to be beneficial in both the titanium particle-induced osteolysis calvarial and the murine ovariectomy-induced bone loss. Collectively, our results suggested that celastrol is promising for the prevention of aseptic prosthetic loosening and osteoporosis in the treatment of osteolytic diseases induced by disrupted osteoclast formation and function.

Celastrol Attenuates RANKL-Induced Osteoclastogenesis in vitro and Reduces Titanium Particle-Induced Osteolysis and Ovariectomy-Induced Bone Loss in vivo

Excessive bone resorption by osteoclasts contributes significantly to osteoclast-related diseases such as periprosthetic osteolysis and osteoporosis. Osteolysis in a titanium particle-induced calvarial model and bone loss in an ovariectomized mice model occurred similarly to those in humans; thus, these models can be used to evaluate potential therapies for aseptic prosthetic loosening and osteoporosis. Celastrol, which is extracted from the seeds of the genus Tripterygium, has been thoroughly investigated for its anti-inflammatory and anti-cancer pharmacological effects. However, the mechanisms involving bone metabolism by which celastrol inhibits osteoclastogenesis are not yet fully understood. We demonstrated that celastrol inhibited the receptor activator of nuclear factor κB ligand-induced osteoclastogenesis and the bone resorptive function of osteoclasts in vitro by inhibiting the activation of transforming growth factor β-activated kinase 1-mediated NF-κB and mitogen-activated protein kinase signaling pathways and downregulating osteoclastogenesis marker-related genes. Furthermore, celastrol was also shown to be beneficial in both the titanium particle-induced osteolysis calvarial and the murine ovariectomy-induced bone loss. Collectively, our results suggested that celastrol is promising for the prevention of aseptic prosthetic loosening and osteoporosis in the treatment of osteolytic diseases induced by disrupted osteoclast formation and function.

Celastrol Prevents Oxidative Stress Effects on FSHR, PAPP, and CYP19A1 Gene Expression in Cultured Human Granulosa-Lutein Cells

Regulation of oxidative stress (OS) is important to prevent damage to female reproductive physiology. While normal OS levels may have a regulatory role, high OS levels may negatively affect vital processes such as folliculogenesis or embryogenesis. The aim of this work was to study OS induced by glucose, a reactive oxygen species generator, or peroxynitrite, a reactive nitrogen species generator, in cultured human granulosa-lutein (hGL) cells from oocyte donors, analyzing expression of genes involved in oocyte maturation (FSHR, PAPP, and CYP19A1) and OS damage response (ALDH3A2). We also evaluated the effect of celastrol as an antioxidant. Our results showed that although both glucose and peroxynitrite produce OS increments in hGL cells, only peroxynitrite treatment increases ALDH3A2 and PAPP gene expression levels and decreases FSHR gene expression levels. Celastrol pre-treatment prevents this effect of peroxynitrite. Interestingly, when celastrol alone was added, we observed a reduction of the expression of all genes studied, which was independent of both OS inductors. In conclusion, regulation of OS imbalance by antioxidant substances such as celastrol may prevent negative effects of OS in female fertility. In addition to the antioxidant activity, celastrol may well have an independent role on regulation of gene expression in hGL cells.

Anti-obesity Medications in Cancer Therapy: A Comprehensive Insight

The interplay between cancer and obesity is multifactorial and complex with the increased risk of cancer development in obese individuals posing a significant threat. Obesity leads to the upregulation or hyperactivation of several oncogenic pathways in cancer cells, which drives them towards a deleterious phenotype. The cross-talk between cancer and obesity is considered a large contributing factor in the development of chemotherapeutic drug resistance and the resistance to radiotherapy. The link between obesity and the development of cancer is so strong that a medication that demonstrates effectiveness against both conditions would serve as an essential step. In this context, anti-obesity medications provide a worthy list of candidates based on their chemo-preventive potential and chemotherapeutic properties. The current study focuses on exploring the potential of anti-obesity medicines as dual anticancer drugs. These medications target several key signaling pathways (e.g., AMPK, PI3K/Akt/mTOR, MAPK, NF-κB, JNK/ERK), which prove to be crucial for both cancer growth and metastases. Some of these drugs also play an important role in attenuating the signaling and cellular events which incite cancer-obesity cross-talk and demonstrate efficient counteraction of neoplastic transformation. Thus, this review highlights a comprehensive view of the potential use of anti-obesity medicines to treat both cancer and obesity for patients exhibiting both comorbities.

Antimicrobial Activity and Mode of Action of Celastrol, a Nortriterpen Quinone Isolated from Natural Sources

Species of the Celastraceae family are traditionally consumed in different world regions for their stimulating properties. Celastrol, a triterpene methylene quinone isolated from plants of celastraceas, specifically activates satiety centers in the brain that play an important role in controlling body weight. In this work, the antimicrobial activity and mechanism of action of celastrol and a natural derivative, pristimerin, were investigated in Bacillus subtilis. Celastrol showed a higher antimicrobial activity compared with pristimerin, being active against Gram-positive bacteria with minimum inhibitory concentrations (MICs) that ranged between 0.16 and 2.5 µg/mL. Killing curves displayed a bactericidal effect that was dependent on the inoculum size. Monitoring of macromolecular synthesis in bacterial populations treated with these compounds revealed inhibition in the incorporation of all radiolabeled precursors, but not simultaneously. Celastrol at 3 µg/mL and pristimerin at 10 µg/mL affected DNA and RNA synthesis first, followed by protein synthesis, although the inhibitory action on the uptake of radiolabeled precursors was more dramatic with celastrol. This compound also caused cytoplasmic membrane disruption observed by potassium leakage and formation of mesosome-like structures. The inhibition of oxygen consumption of whole and disrupted cells after treatments with both quinones indicates damage in the cellular structure, suggesting the cytoplasmic membrane as a potential target. These findings indicate that celastrol could be considered as an interesting alternative to control outbreaks caused by spore-forming bacteria.

Tripterine ameliorates monosodium urate crystal-induced gouty arthritis by altering macrophage polarization via the miR-449a/NLRP3 axis

OBJECTIVE

Tripterine (Trip) is frequently applied to alleviate inflammation in various diseases such as rheumatoid arthritis. Macrophages have both anti-inflammatory and pro-inflammatory functions. However, whether Trip can inhibit cell inflammation in gouty arthritis (GA) remains undiscovered and whether the mechanism involved in macrophage polarization is also undetermined. This paper aims to study the effects of Trip on inflammation and macrophage polarization in GA.

METHODS

Monosodium urate (MSU) crystals were used to establish GA mouse models, and bone marrow-derived macrophages (BMDMs) were induced to construct GA cell models. Pretreatments of Trip and injection of Antagomir-449a/Agomir-449a were performed on mice for 6 days. The effects of Trip and miR-449 on toe swelling, joint damage of GA mouse were examined. The alternations on cell morphology, cell proliferation marker Ki67, inflammatory cytokines, NLRP3 inflammasome, and NF-κB signaling-related proteins were also determined both in vivo and in vitro. Dual-luciferase reporter gene assay and RIP assay were adopted to estimate the targeting relationship between miR-449a and NLRP3.

RESULTS

GA mouse model had increased M1 macrophage, intensified inflammation response, along with suppressed miR-449a expression. Following administration of Trip attenuated cell inflammation, promoted macrophage polarize to M2 phenotype, elevated miR-449a expression, repressed the phosphorylation levels of NF-κB signaling-related proteins, and diminished IκBα expression in vivo and in vitro. However, inhibition of miR-449a hindered the favorable effect of Trip on GA and increased NLRP3 inflammasome expression. MiR-449a directly targeted NLRP3. Overexpression of NLRP3 partially eliminated the biological effects of miR-449a agonist.

CONCLUSION

Trip regulates macrophage polarization through miR-449a/NLRP3 axis and the STAT3/NF-κB pathway to mitigate GA. The elucidation on the molecular mechanism of Trip in GA may provide theoretical guidance for clinical therapy of GA.

Folic acid-modified celastrol nanoparticles: synthesis, characterization, anticancer activity in 2D and 3D breast cancer models

Celastrol is used in traditional Chinese medicine for treating cancers. However, its low water solubility and poor tumour selection represent major pitfalls for clinical application. In the present study, gold nanoparticle (AuNP) firstly was conjugated with PVP-co-2-dimethylaminoethyl methacrylate (Polymer) and celastrol then modified by folic acid. The as-prepared folate receptor-targeted celastrol AuNP (FCA) was characterized using attenuated total reflection Fourier transform infrared spectroscopy, UV-Vis spectrometry, transmission electron microscope, and inductively coupled plasma mass spectrometry. The physical properties of FCA were also determined in solubility, drug encapsulation and in vitro drug release. Its anticancer activities were assessed in the 2D and 3D breast cancer models. The results showed that FCA was synthesized successfully with good solubility, high encapsulation efficiency and loading content. FCA showed the optimal cumulative release at pH 5.0 and high cellular uptake and exhibited significant inhibition on breast cancer cells. FCA also induced more significant apoptosis either in 2D and 3D breast cancer model than the celastrol AuNP and celastrol alone. These findings demonstrate that FCA improves water solubility of celastrol and enhances its anticancer activities against breast cancer. FCA might be a potential candidate of anticancer drug for breast cancer in the future if further development.

Celastrol attenuates arterial and valvular calcification via inhibiting BMP2/Smad1/5 signalling

Vascular calcification is an important risk factor for the mortality and morbidity in chronic kidney disease (CKD). Unfortunately, until now there is no certain medication targeting vascular calcification in CKD. In this study, we explored the inhibitory effect of celastrol on high calcium–induced vascular calcification and the underlying molecular mechanisms. Cell proliferation assay showed that celastrol inhibited aortic valve interstitial cell (VIC) and vascular smooth muscle cell (VSMC) proliferation when its concentration was higher than 0.6 μmol/L. 0.8 μmol/L celastrol inhibited the expression of osteogenic genes and calcium deposition induced by high‐calcium medium in both AVICs and VSMCs. In mouse vascular calcification model induced by adenine combined with vitamin D, alizarin red and immunostaining showed that celastrol inhibited pro‐calcification gene expression and calcium deposition in aortic wall and aortic valve tissues. At the molecular level, celastrol inhibited the increase of BMP2, phosphorylated Smad1/5 (p‐Smad1/5) and non‐phosphorylated β‐catenin (n‐p‐β‐catenin) induced by high‐calcium medium both in vitro and in vivo. Also, BMP2 overexpression reversed the anti‐calcification effects of celastrol by recovering the decrease of p‐Smad1/5 and n‐p‐β‐catenin. Furthermore, celastrol prevented the up‐regulation of BMPRII and down‐regulation of Smad6 induced by high calcium, and this protectory effect can be abolished by BMP2 overexpression. In conclusion, our data for the first time demonstrate that celastrol attenuates high calcium–induced arterial and valvular calcification by inhibiting BMP2/Smad1/5 signalling, which may provide a novel therapeutic strategy for arterial and valvular calcification in patients with CKD.

A natural product solution to aging and aging-associated diseases

Aging is a natural biological progress accompanied by the gradual decline in physiological functions, manifested by its close association with an increased incidence of human diseases and higher vulnerability to death. Those diseases include neurological disorders, cardiovascular diseases, diabetes, and cancer, many of which are currently without effective cures. Even though aging is inevitable, there are still interventions that can be developed to prevent/delay the onset and progression of those aging-associated diseases and extend healthspan and/or lifespan. Here, we review decades of research that reveals the molecular pathways underlying aging and forms the biochemical basis for anti-aging drug development. Importantly, due to the vast chemical space of natural products and the rich history of herb medicines in treating human diseases documented in different cultures, natural products have played essential roles in aging research. Using several of the most promising natural products and their derivatives as examples, we discuss how natural products serve as an inspiration resource that helped the identification of key components/pathways underlying aging, their mechanisms of action inside the cell, and the functional scaffolds or targeting mechanisms that can be learned from natural products for drug engineering and optimization. We argue that natural products might eventually provide a solution to aging and aging-associated diseases.

Naturally Derived Heme-Oxygenase 1 Inducers and Their Therapeutic Application to Immune-Mediated Diseases

Heme oxygenase (HO) is the primary antioxidant enzyme involved in heme group degradation. A variety of stimuli triggers the expression of the inducible HO-1 isoform, which is modulated by its substrate and cellular stressors. A major anti-inflammatory role has been assigned to the HO-1 activity. Therefore, in recent years HO-1 induction has been employed as an approach to treating several disorders displaying some immune alterations components, such as exacerbated inflammation or self-reactivity. Many natural compounds have shown to be effective inductors of HO-1 without cytotoxic effects; among them, most are chemicals present in plants used as food, flavoring, and medicine. Here we discuss some naturally derived compounds involved in HO-1 induction, their impact in the immune response modulation, and the beneficial effect in diverse autoimmune disorders. We conclude that the use of some compounds from natural sources able to induce HO-1 is an attractive lifestyle toward promoting human health. This review opens a new outlook on the investigation of naturally derived HO-1 inducers, mainly concerning autoimmunity.

Celastrol Protects RPE Cells from Oxidative Stress-Induced Cell Death via Activation of Nrf2 Signaling Pathway

PURPOSE

Oxidative stress to retinal pigment epithelial (RPE) cells and inflammation are closely related to the pathogenesis of age-related macular degeneration (AMD). Celastrol is a natural compound isolated from the root of Tripterygium wilfordii. Celastrol has been shown to have potent anti-inflammatory and anti-tumor effects in multiple disease models. The objective of this study was to test the anti-oxidative effects of celastrol in RPE cells and to investigate the underlying mechanisms.

METHODS

ARPE-19 cells were treated with hydrogen peroxide (H2O2) and menadione alone or in combination with celastrol. Cell viability and apoptosis were examined by CCK-8 and TUNEL assay, respectively. The expression of Nrf2 and its target genes, such as GCLM and HO-1 was determined by Western blotting. The knockdown of Nrf2 was done by transfecting ARPE-19 cells with lentivirus encoding shRNA against Nrf2. The knockdown efficiency was determined by real-time quantitative PCR and Western blotting.

RESULTS

Treatment of ARPE-19 cells with celastrol significantly attenuated the toxic effects of both H2O2 and menadione. Treatment with celastrol enhanced the expression of transcription factor Nrf2 and its targets, GCLM and HO-1. Knockdown of Nrf2 expression by shRNA partially abolished the protective effects of celastrol. Chemical inhibition of glutathione synthesis by L-buthionine-S,R-sulfoximine (BSO) completely abolished the protective effects of celastrol against H2O2 and menadione-induced damage. However, chemical inhibition of HO-1 activity by ZnPPIX did not reduce the protective effects of celastrol.

CONCLUSION

This study provides evidence that treatment of RPE cells with celastrol shows potent protective effects against oxidative insults via activation of Nrf2 signaling pathway and upregulation of GCLM expression. This finding suggests that celastrol might be used as a potential therapeutic agent for oxidative stress-related eyes diseases, such as AMD.

Celastrol attenuates collagen-induced arthritis via inhibiting oxidative stress in rats

The present work aimed to investigate the anti-rheumatism effect and the mechanism of celastrol in collagen-induced arthritis (CIA) rats. The CIA model was established in male Wistar rats by intradermal injection of bovine collagen-II in complete Freund's adjuvant (CFA) at the base of tail. The rats received oral administration of celastrol for 28 days. A variety of indicators, including paw swelling and arthritis scores, were measured for anti-rheumatism effect. Celastrol treatment attenuated paw swelling and arthritis scores in CIA rats. Celastrol improved the spleen and thymus indexes in CIA rats. The increased levels of inflammatory cytokines, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and interferon (IFN)-γ, were abolished by celastrol treatment. In addition, the weakened superoxide dismutase (SOD) activity, the increased levels of malondialdehyde (MDA), and superoxide anions, and enhanced NADPH oxidase (Nox) activity were all reversed by celastrol treatment. Nox4 overexpression reversed the attenuating effects of celastrol on paw swelling and arthritis scores in CIA rats. The celastrol-induced improvement in spleen and thymus indexes in CIA rats was inhibited by Nox4 overexpression. Nox4 overexpression reversed the abolishing effects of celastrol on the increases of TNF-α, IL-1β, IL-6, and IFN-γ levels in the serum of CIA rats. These results demonstrated that celastrol improved rheumatism in arthritis via inhibiting oxidative stress.

Tripterine Restrains the Aggressiveness of Hepatocellular Carcinoma Cell via Regulating miRNA-532-5p/CXCL2 Axis

Introduction

Triterpene has attracted considerable interests because it exhibits anticancer effects. However, the effects of tripterine on hepatocellular carcinoma (HCC) are not well studied. In the current study, the mechanism of tripterine on HCC cells growth and metastasis was examined.

Methods

The inhibitory effect on the growth and aggressiveness in HCC cells was analyzed by Cell Counting Kit-8 (CCK-8), wound healing and Transwell assay. The levels of microRNA-532-5p (miR-532-5p) in HCC cells and tissues were measured using qRT-PCR. The expression of chemokine (C-X-C Motif) ligand 2 (CXCL2) was determined by Western blotting and immunohistochemistry (IHC). Luciferase reporter gene assay was used to validate the binding between miR-532-5p and CXCL2. The impact of tripterine on the growth and metastasis of HCC cells in vivo was analyzed using transplanted tumor model and experimental lung metastasis model, respectively.

Results

We found that tripterine inhibited HCC cells proliferation, migration ability and invasion. Under tripterine treatment, the level of miR-532-5p was strikingly raised, and overexpression of miR‑532-5p reduced cell viability and metastatic-related traits. In addition, we identified CXCL2 as a target of miR-532-5p in HCC. Rescue experiments indicated that overexpression of CXCL2 restored the migration and invasive capacity of HCC cells inhibited by miR-532-5p or tripterine treatment. Finally, the tumor growth and metastatic ability of HCC MHCC97H cell in vivo were also significantly restrained by tripterine. The expression of CXCL2 was distinctly decreased and miR-532-5p level was increased by tripterine in vivo.

Conclusion

In conclusion, tripterine inhibits the growth, migration ability and invasiveness of HCC cells through intervening miR-532-5p/CXCL2.

Therapeutic targets of thunder god vine (Tripterygium wilfordii hook) in rheumatoid arthritis (Review)

Celastrol and triptolide, chemical compounds isolated from Tripterygium wilfordii hook (also known as thunder god vine), are effective against rheumatoid arthritis (RA). Celastrol targets numerous signaling pathways involving NF‑κB, endoplasmic reticulum Ca2+‑ATPase, myeloid differentiation factor 2, toll‑like receptor 4, pro‑inflammatory chemokines, DNA damage, cell cycle arrest and apoptosis. Triptolide, inhibits NF‑κB, the receptor activator of NF‑κB (RANK)/RANK ligand/osteoprotegerin signaling pathway, cyclooxygenase‑2, matrix metalloproteases and cytokines. The present review examined the chemistry and bioavailability of celastrol and triptolide, and their molecular targets in treating RA. Clinical studies have demonstrated that T. wilfordii has several promising bioactivities, but its multi‑target toxicity has restricted its application. Thus, dosage control and structural modification of T. wilfordii are required to reduce the toxicity. In this review, future directions for research into these promising natural products are discussed.

Terpenoids, Cannabimimetic Ligands, beyond the Cannabis Plant

Medicinal use of Cannabis sativa L. has an extensive history and it was essential in the discovery of phytocannabinoids, including the Cannabis major psychoactive compound—Δ9-tetrahydrocannabinol (Δ9-THC)—as well as the G-protein-coupled cannabinoid receptors (CBR), named cannabinoid receptor type-1 (CB1R) and cannabinoid receptor type-2 (CB2R), both part of the now known endocannabinoid system (ECS). Cannabinoids is a vast term that defines several compounds that have been characterized in three categories: (i) endogenous, (ii) synthetic, and (iii) phytocannabinoids, and are able to modulate the CBR and ECS. Particularly, phytocannabinoids are natural terpenoids or phenolic compounds derived from Cannabis sativa. However, these terpenoids and phenolic compounds can also be derived from other plants (non-cannabinoids) and still induce cannabinoid-like properties. Cannabimimetic ligands, beyond the Cannabis plant, can act as CBR agonists or antagonists, or ECS enzyme inhibitors, besides being able of playing a role in immune-mediated inflammatory and infectious diseases, neuroinflammatory, neurological, and neurodegenerative diseases, as well as in cancer, and autoimmunity by itself. In this review, we summarize and critically highlight past, present, and future progress on the understanding of the role of cannabinoid-like molecules, mainly terpenes, as prospective therapeutics for different pathological conditions.

Celastrol Attenuates Angiotensin II-Induced Cardiac Remodeling by Targeting STAT3

RATIONALE

Excessive Ang II (angiotensin II) levels lead to a profibrotic and hypertrophic milieu that produces deleterious remodeling and dysfunction in hypertension-associated heart failure. Agents that disrupt Ang II-induced cardiac dysfunction may have clinical utility in the treatment of hypertension-associated heart failure.

OBJECTIVE

We have examined the potential effect of celastrol-a bioactive compound derived from the Celastraceae family-on Ang II-induced cardiac dysfunction.

METHODS AND RESULTS

In rat primary cardiomyocytes and H9C2 (rat cardiomyocyte-like H9C2) cells, celastrol attenuates Ang II-induced cellular hypertrophy and fibrotic responses. Proteome microarrays, surface plasmon resonance, competitive binding assays, and molecular simulation were used to identify the molecular target of celastrol. Our data showed that celastrol directly binds to and inhibits STAT (signal transducer and activator of transcription)-3 phosphorylation and nuclear translocation. Functional tests demonstrated that the protection of celastrol is afforded through targeting STAT3. Overexpression of STAT3 dampens the effect of celastrol by partially rescuing STAT3 activity. Finally, we investigated the in vivo effect of celastrol treatment in mice challenged with Ang II and in the transverse aortic constriction model. We show that celastrol administration protected heart function in Ang II-challenged and transverse aortic constriction-challenged mice by inhibiting cardiac fibrosis and hypertrophy.

CONCLUSIONS

Our studies show that celastrol inhibits Ang II-induced cardiac dysfunction by inhibiting STAT3 activity.

Mechanisms of antimicrobial resistance in Stenotrophomonas maltophilia: a review of current knowledge

Introduction: Stenotrophomonas maltophilia is a prototype of bacteria intrinsically resistant to antibiotics. The reduced susceptibility of this microorganism to antimicrobials mainly relies on the presence in its chromosome of genes encoding efflux pumps and antibiotic inactivating enzymes. Consequently, the therapeutic options for treating S. maltophilia infections are limited.Areas covered: Known mechanisms of intrinsic, acquired and phenotypic resistance to antibiotics of S. maltophilia and the consequences of such resistance for treating S. maltophilia infections are discussed. Acquisition of some genes, mainly those involved in co-trimoxazole resistance, contributes to acquired resistance. Mutation, mainly in the regulators of chromosomally-encoded antibiotic resistance genes, is a major cause for S. maltophilia acquisition of resistance. The expression of some of these genes is triggered by specific signals or stressors, which can lead to transient phenotypic resistance.Expert opinion: Treatment of S. maltophilia infections is difficult because this organism presents low susceptibility to antibiotics. Besides, it can acquire resistance to antimicrobials currently in use. Particularly problematic is the selection of mutants overexpressing efflux pumps since they present a multidrug resistance phenotype. The use of novel antimicrobials alone or in combination, together with the development of efflux pumps' inhibitors may help in fighting S. maltophilia infections.

Molecular mechanism of celastrol in the treatment of systemic lupus erythematosus based on network pharmacology and molecular docking technology

BACKGROUND

Network pharmacology uses bioinformatics to broaden our understanding of drug actions and thereby advance drug discovery. Here we apply network pharmacology to generate testable hypotheses about the multi-target mechanism of celastrol against systemic lupus erythematosus (SLE).

METHODS

We reconstructed drug-target pathways and networks to predict the likely protein targets of celastrol and the main interactions between those targets and the drug. Then we validated our predictions of candidate targets by performing docking studies with celastrol.

RESULTS

The results suggest that celastrol acts against SLE by regulating the function of several signaling proteins, such as interleukin 10, tumor necrosis factor, and matrix metalloprotein 9, which regulate signaling pathways involving mitogen-activated protein kinase and tumor necrosis factor as well as apoptosis pathways. Celastrol is predicted to affect networks involved mainly in cytokine activity, cytokine receptor binding, receptor ligand activity, receptor regulator activity, and cofactor binding. Molecular docking analysis showed that hydrogen bonding and π-π stacking were the main forms of interaction.

CONCLUSIONS

This network pharmacology strategy may be useful for discovery of multi-target drugs against complex diseases, specifically, it provides protein targets associated with SLE that may be further tested for therapeutic potential by celastrol.

Tripterine up-regulates miR-223 to alleviate lipopolysaccharide-induced damage in murine chondrogenic ATDC5 cells

Tripterine, also known as celastrol, is a main natural ingredient in Tripterygium wilfordii. Tripterine has a variety of pharmacological functions, and the therapeutic potential of tripterine in many kinds of inflammation-linked diseases has been revealed. However, the function of tripterine on osteoarthritis still remains unclear. The objective of this study was to study the function of tripterine (TPR) on lipopolysaccharide (LPS)-injured chondrocyte. ATDC5 cells were treated with tripterine after LPS stimulation and then cell survival, the release of pro-inflammatory cytokines, and the expression of chondrogenic differentiation-associated proteins were assessed by performing CCK-8, flow cytometry, reverse transcription quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), and Western blot. Moreover, the expression of miR-223 and core factors in PI3K/AKT and nuclear factor kappa B (NF-κB) signaling was tested by RT-qPCR/Western blot. LPS stimulation significantly reduced ATDC5 cells viability, induced apoptosis, and increased the release of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. Tripterine protected ATDC5 cells against LPS-induced chondrocyte loss and the release of IL-6 and TNF-α. miR-223 was down-regulated by LPS, while was up-regulated by tripterine. The protective actions of tripterine were eliminated when miR-223 was silenced. Besides, tripterine inhibited hypertrophic differentiation induced by LPS, and the inhibitory effects of tripterine on hypertrophic differentiation could be abolished when miR-223 was silenced. Furthermore, tripterine activated PI3K/AKT pathway and deactivated NF-κB pathway. And the regulatory effects of tripterine on these two pathways were abolished by miR-223 silence. This study revealed that tripterine protected ATDC5 cells against LPS-induced cell damage possibly via up-regulation of miR-223 and modulation of NF-κB and PI3K/AKT pathways.

Celastrol Protects From Cholestatic Liver Injury Through Modulation of SIRT1-FXR Signaling

Celastrol, derived from the roots of the Tripterygium Wilfordi, shows a striking effect on obesity. In the present study, the role of celastrol in cholestasis was investigated using metabolomics and transcriptomics. Celastrol treatment significantly alleviated cholestatic liver injury in mice induced by α-naphthyl isothiocyanate (ANIT) and thioacetamide (TAA). Celastrol was found to activate sirtuin 1 (SIRT1), increase farnesoid X receptor (FXR) signaling and inhibit nuclear factor-kappa B and P53 signaling. The protective role of celastrol in cholestatic liver injury was diminished in mice on co-administration of SIRT1 inhibitors. Further, the effects of celastrol on cholestatic liver injury were dramatically decreased in Fxr-null mice, suggesting that the SIRT1-FXR signaling pathway mediates the protective effects of celastrol. These observations demonstrated a novel role for celastrol in protecting against cholestatic liver injury through modulation of the SIRT1 and FXR.

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.

Oral pre-administration of Purslane polysaccharides enhance immune responses to inactivated foot-and-mouth disease vaccine in mice

Background

Foot-and-mouth disease (FMD) is one of the greatest disease threats to animal husbandry worldwide. Though various vaccines against foot-and-mouth disease virus (FMDV) have been developed, vaccine effectiveness is still not satisfactory. In this work, we studied the potential ability of Purslane polysaccharide (POL-P3b) as a nutrient food additive to enhance immune responses to FMD vaccination in mice.

Results

Our results demonstrated that oral administration of POL-P3b at mid- and high-doses significantly enhanced the FMDV-specific cellular and humoral immune responses in mice and increased the concentration of Ca²⁺ in lymphocytes. Importantly, POL-P3b could promote intestinal DC maturation and stimulate the secretion of intestinal SIgA in a dose-dependent manner. Moreover, the acute toxicity study showed that POL-P3b was non-toxic and safe in mice.

Conclusion

Our findings provided solid evidence that POL-P3b might be a novel immunostimulator and a boosting agent for increasing the efficacy of FMD vaccination, and the mechanism was related to stimulating the intestinal mucosal immune function that subsequently enhanced the efficacy of FMD vaccination through pre-administration of oral POL-P3b.