Oridonin attenuates carrageenan-induced pleurisy via activation of the KEAP-1/Nrf2 pathway and inhibition of the TXNIP/NLRP3 and NF-κB pathway in mice

Biflavonoid Methylchamaejasmin and Khaya grandifoliola Extract Inhibit NLRP3 Inflammasome in THP-1 Cell Model of Neuroinflammation

Neuroinflammation is a common hallmark of Alzheimer's disease (AD), with NLRP3 inflammasome proven to be activated in microglia of AD patients' brains. In this study, a newly isolated biflavonoid (7,7'-di-O-methylchamaejasmin/M8) and a crude extract of the plant Khaya grandifoliola (KG) were investigated for their inhibitory effect on inflammasome activation. In preliminary experiments, M8 and KG showed no cytotoxicity on human macrophage-like differentiated THP-1 cells and exhibited anti-inflammatory inhibition of nitric oxide produced following lipopolysaccharide stimulation. Furthermore, M8 and KG blocked IL-1β and IL-18 production by reducing NLRP3 inflammasome components including NFκB, NLRP3, Caspase-1, pro-IL-1β, and pro-IL-18 at the mRNA and protein levels. Regarding the formation of ASC (apoptosis-associated speck-like protein containing a CARD) specks during inflammasome activation, the size and fluorescent intensity of the existing specks were unchanged across all treatment conditions. However, M8 and KG treatments were shown to prevent further speck formation. In addition, experiments on amyloid β phagocytosis showed that M8 and KG pretreatments can restore the phagocytic activity of THP-1 cells, which was impaired following inflammasome activation. Altogether, our findings describe for the first time a promising role of biflavonoids and KG extract in preventing inflammasome activation and protecting against neuroinflammation, a key factor in AD development.

Hit-to-Lead Optimization of the Natural Product Oridonin as Novel NLRP3 Inflammasome Inhibitors with Potent Anti-Inflammation Activity

Targeting NLRP3 inflammasome with inhibitors is a novel strategy for NLRP3-driven diseases. Herein, hit compound 5 possessing an attractive skeleton was identified from our in-house database of oridonin, and then a potential lead compound 32 was obtained by optimization of 5, displaying two-digit nanomolar inhibition on NLRP3. Moreover, compound 32 showed enhanced safety index (SI) relative to oridonin (IC50 = 77.2 vs 780.4 nM, SI = 40.5 vs 8.5) and functioned through blocking ASC oligomerization and interaction of NLRP3-ASC/NEK7, thereby suppressing NLRP3 inflammasome assembly and activation. Furthermore, diverse agonists-induced activations of NLRP3 could be impeded by compound 32 without altering NLRC4 or AIM2 inflammasome. Crucially, compound 32 possessed tolerable pharmaceutical properties and significant anti-inflammatory activity in MSU-induced gouty arthritis model. Therefore, this work enriched the SAR of NLRP3 inflammasome inhibitors and provided a potential candidate for the treatment of NLRP3-associated diseases.

Oridonin inhibits bladder cancer survival and immune escape by covalently targeting HK1

BACKGROUND

Hexokinase I (HK1) is highly expressed in a variety of malignancies, regulates glycolytic pathway in cancer cells, and thus considered to be one of the promising molecular targets for cancer therapy. Nonetheless, the development of a specific inhibitor against HK1 remains elusive.

PURPOSE

This study aims to elucidate the mechanism by which oridonin inhibits the proliferation and immune evasion of bladder cancer cells, specifically through the suppression of HK1.

METHODS

To examine the mechanisms by which oridonin directly binds to cysteines of HK1 and inhibits bladder cancer growth, this study utilized a variety of methods. These included the Human Proteome Microarray, Streptavidin-agarose affinity assay, Biolayer Interferometry (BLI) ainding analysis, Mass Spectrometry, Cellular Thermal Shift Assay, Extracellular Acidification Rate measurement, and Xenotransplant mouse models.

RESULTS

As indicated by our current findings, oridonin forms a covalent bond with Cys-813, located adjacently to glucose-binding domain of HK1. This suppresses the enzymatic activity of HK1, leading to an effective reduction of glycolysis, which triggers cell death via apoptosis in cells derived from human bladder cancer. Significantly, oridonin also inhibits lactate-induced PD-L1 expression in bladder cancer. Furthermore, pairing oridonin with a PD-L1 inhibitor amplifies the cytotoxicity of CD8+ T cells against bladder cancer.

CONCLUSION

This research strongly suggests that oridonin serves as a covalent inhibitor of HK1. Moreover, it indicates that functional cysteine residue of HK1 could operate as viable targets for selective inhibition. Consequently, oridonin exhibits substantial potential for the evolution of anti-cancer agents targeting the potential therapeutic target HK1 via metabolism immunomodulation.

A review of studies on the implication of NLRP3 inflammasome for Parkinson's disease and related candidate treatment targets

Parkinson's disease (PD) is a neurodegenerative disease for which the prevalence is second only to Alzheimer's disease (AD). This disease primarily affects people of middle and old age, significantly impacting their health and quality of life. The main pathological features include the degenerative nigrostriatal dopaminergic (DA) neuron loss and Lewy body (LB) formation. Currently, available PD medications primarily aim to alleviate clinical symptoms, however, there is no universally recognized therapy worldwide that effectively prevents, clinically treats, stops, or reverses the disease. Consequently, the evaluation and exploration of potential therapeutic targets for PD are of utmost importance. Nevertheless, the pathophysiology of PD remains unknown, and neuroinflammation mediated by inflammatory cytokines that prompts neuron death is fundamental for the progression of PD. The nucleotide-binding oligomerization domain-like receptor pyrin domain-containing 3 (NLRP3) inflammasome is a key complex of proteins linking the neuroinflammatory cascade in PD. Moreover, mounting evidence suggests that traditional Chinese medicine (TCM) alleviates PD by suppressing the NLRP3 inflammasome. This article aims to comprehensively review the available studies on the composition and activating mechanism of the NLRP3 inflammasome, along with its significance in PD pathogenesis and potential treatment targets. We also review natural products or synthetic compounds which reduce neuroinflammation via modulating NLRP3 inflammasome activity, aiming to identify new targets for future PD diagnosis and treatment through the exploration of NLRP3 inhibitors. Additionally, this review offers valuable references for developing new PD treatment methods.

Inflammasome: structure, biological functions, and therapeutic targets

Inflammasomes are a group of protein complex located in cytoplasm and assemble in response to a wide variety of pathogen-associated molecule patterns, damage-associated molecule patterns, and cellular stress. Generally, the activation of inflammasomes will lead to maturation of proinflammatory cytokines and pyroptotic cell death, both associated with inflammatory cascade amplification. A sensor protein, an adaptor, and a procaspase protein interact through their functional domains and compose one subunit of inflammasome complex. Under physiological conditions, inflammasome functions against pathogen infection and endogenous dangers including mtROS, mtDNA, and so on, while dysregulation of its activation can lead to unwanted results. In recent years, advances have been made to clarify the mechanisms of inflammasome activation, the structural details of them and their functions (negative/positive) in multiple disease models in both animal models and human. The wide range of the stimuli makes the function of inflammasome diverse and complex. Here, we review the structure, biological functions, and therapeutic targets of inflammasomes, while highlight NLRP3, NLRC4, and AIM2 inflammasomes, which are the most well studied. In conclusion, this review focuses on the activation process, biological functions, and structure of the most well-studied inflammasomes, summarizing and predicting approaches for disease treatment and prevention with inflammasome as a target. We aim to provide fresh insight into new solutions to the challenges in this field.

Anticancer mechanisms on pyroptosis induced by Oridonin: New potential targeted therapeutic strategies

Pyroptosis is a type of inflammatory cell death that is triggered by the formation of pores on the cell membrane by gasdermin (GSDM) family proteins. This process activates inflammasomes and leads to the maturation and release of proinflammatory cytokines such as interleukin-1β (IL-1β) and interleukin-18 (IL-18). Pyroptosis, a form of programmed cell death, has been found to be associated with various biomolecules such as caspases, granzymes, non-coding RNA (lncRNA), reactive oxygen species (ROS), and NOD-like receptor protein 3 (NLRP3). These biomolecules have been shown to play a dual role in cancer by affecting cell proliferation, metastasis, and the tumor microenvironment (TME), resulting in both tumor promotion and anti-tumor effects. Recent studies have found that Oridonin (Ori) has anti-tumor effects by regulating pyroptosis through various pathways. Ori can inhibit pyroptosis by inhibiting caspase-1, which is responsible for activating pyroptosis of the canonical pathway. Additionally, Ori can inhibit pyroptosis by inhibiting NLRP3, which is responsible for activating pyroptosis of the noncanonical pathway. Interestingly, Ori can also activate pyroptosis by activating caspase-3 and caspase-8, which are responsible for activating pyroptosis of the emerging pathway; Ori has been found to be effective in inhibiting pyroptosis by blocking the action of perforin, which is responsible for facilitating the entry of granzyme into cells and activating pyroptosis. Additionally, Ori plays a crucial role in regulating pyroptosis by promoting the accumulation of ROS while inhibiting the ncRNA and NLRP3 pathways. It is worth noting that all of these pathways ultimately regulate pyroptosis by influencing the cleavage of GSDM, which is a key factor in the process. These studies concludes that Ori has extensive anti-cancer effects that are related to its potential regulatory function on pyroptosis. The paper summarizes several potential ways in which Ori participates in the regulation of pyroptosis, providing a reference for further study on the relationship between Ori, pyroptosis, and cancer.

Oridonin inhibits SARS-CoV-2 replication by targeting viral proteinase and polymerase

COVID-19 has become a global public health crisis since its outbreak in China in December 2019. Currently there are few clinically effective drugs to combat SARS-CoV-2 infection. The main protein (Mpro), papain-like protease (PLpro) and RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 are involved in the viral replication, and might be prospective targets for anti-coronavirus drug development. Here, we investigated the antiviral activity of oridonin, a natural small-molecule compound, against SARS-CoV-2 infection in vitro. The time-of-addition analysis showed that oridonin efficiently inhibited SARS-CoV-2 infection by interfering with the genome replication at the post-entry stage. Mechanistically, the inhibition of viral replication by oridonin depends on the oxidation activity of α, β-unsaturated carbonyl. Further experiments showed that oridonin not only effectively inhibited SARS-CoV-2 Mpro activity, but also had some inhibitory effects on PLpro-mediated deubiquitinating and viral polymerase-catalyzed RNA elongation activities at high concentrations. In particular, oridonin could inhibit the bat SARS-like CoV and the newly emerged SARS-CoV-2 omicron variants (BA.1 and BA.2), which highlights its potential as a pan-coronavirus antiviral agent. Overall, our data provide strong evidence that oridonin is an efficient antiviral agent against SARS-CoV-2 infection.

Oridonin attenuates the progression of atherosclerosis by inhibiting NLRP3 and activating Nrf2 in apolipoprotein E-deficient mice

Oridonin, a well-known traditional Chinese herbal medicinal product isolated from Isodon rubescens (Hemsl.) H.Hara, has many potential properties, including anti-inflammatory and antioxidant activities. However, there is no evidence whether oridonin have a protective effect on atherosclerosis. This study focused on the effects of oridonin on oxidative stress and inflammation generated from atherosclerosis. The therapeutic effect on atherosclerosis was evaluated by intraperitoneal injection of oridonin in a high-fat fed ApoE^-/- mouse model. We isolated mouse peritoneal macrophages and detected the effect of oridonin on oxidized low-density lipoprotein-induced lipid deposition. Oil red O staining, Masson's staining, dihydroethidium fluorescence staining, immunohistochemical staining, western blotting analysis, immunofluorescence, enzyme-linked immunosorbent assay and quantitative real-time PCR were used to evaluate the effect on atherosclerosis and explore the mechanisms. Oridonin treatment significantly alleviated the progression of atherosclerosis, reduced macrophage infiltration and stabilized plaques. Oridonin could significantly inhibit inflammation associated with NLRP3 activation. Oridonin significantly reduced oxidative stress by blocking Nrf2 ubiquitination and degradation. We also found that oridonin could prevent the formation of foam cells by increasing lipid efflux protein and reducing lipid uptake protein in macrophages. Oridonin has a protective effect on atherosclerosis in ApoE^-/- mice, which may be related to the inhibition of NLRP3 and the stabilization of Nrf2. Therefore, oridonin may be a potential therapeutic agent for atherosclerosis.

Protective effects of sinomenine hydrochloride on lead-induced oxidative stress, inflammation, and apoptosis in mouse liver

Lead, one of the most common heavy metal toxins, seriously affects the health of humans and animals. Sinomenine hydrochloride (SH) shows antioxidative, anti-inflammatory, antiviral, and anticancer properties. Hence, this study investigated the protective effects of SH against Pb-induced liver injury and explored the underlying mechanisms. First, a mouse model of lead acetate (0.5 g/L lead acetate in water, 8 weeks) was established, and SH (100 mg/kg bw in water, 8 weeks) intervention was administered by gavage. Then, the protective effect of SH against lead-induced liver injury was evaluated through serum biochemical analysis, histopathological analysis, and determination of malondialdehyde (MDA) and total antioxidant capacity (T-AOC) levels. The messenger RNA (mRNA) expression levels of the cytokines IL-1β and TNF-α and the apoptosis factors Bax, Bcl-2, and Caspase3 in the liver were detected by quantitative real-time PCR. Then, the expression levels of IL-1β and TNF-α in the liver were detected by ELISA. Immunohistochemical determination of the expression of the apoptosis factors Bax, Bcl-2, and Caspase3 was performed. SH treatment reduced the levels of liver alanine aminotransferase, aspartate aminotransferase (AST), lactate dehydrogenase (LDH), and MDA in Pb-treated mice, indicating that SH protected the liver from injury and oxidative stress in Pb-treated mice. SH also increased the liver T-AOC of Pb-treated mice. Quantitative real-time PCR, ELISA, and immunohistochemical analysis showed that SH inhibited apoptosis, as indicated by the regulation of the mRNA expression of Bax and Bcl-2 and the reduced expression of Caspase3 and pro-inflammatory factors (IL-1β and TNF-α) in the livers of Pb-treated mice. These results suggest that SH protects the mouse liver from Pb-induced injury. The underlying mechanism involves antioxidative, anti-inflammatory, and anti-apoptotic processes.

Thioredoxin-1 regulates IRE1α to ameliorate sepsis-induced NLRP3 inflammasome activation and oxidative stress in Raw 264.7 cell

Sepsis is life-threatening organ dysfunction caused by the dysregulated host response to infection. Endoplasmic reticulum stress (ERS)-mediated inositol-requiring enzyme 1 α (IRE1α) inflammatory signaling pathway is involved in sepsis. NLRP3 inflammasome plays a key role in the activation of caspase-1 and the maturation of IL-1β and IL-18, and finally enhances the inflammatory response. More and more evidences show that ERS is an endogenous trigger of NLRP3 inflammasome. Thioredoxin-1 (Trx-1) is a small ubiquitous thiol-1 protein with redox/inflammation modulatory properties relevant to sepsis pathogenesis. In this study, we investigated the role of Trx-1 in ERS mediated IRE1α/NLRP3 signaling pathway in Raw 264.7 cells. Our results show that Trx-1 reduces the release of inflammatory factors and reactive oxygen species (ROS) by regulating the related proteins in the IRE1α/NLRP3 signaling pathway expression.

Spirolactone-type and enmein-type derivatives as potential anti-cancer agents derived from oridonin

Natural products (NPs) are always the important sources in the field of drug discovery, among which spirolactone-type and enmein-type compounds exhibit a wide range of biological activities, especially anti-tumor activity. Based on previous studies, the spirolactone-type and enmein-type compounds could be derived from natural oridonin (1) by several chemical reactions. Herein, a series of novel spirolactone-type and enmein-type derivatives with different aryl allyl ester substitutions at their C-14 hydroxyl group were designed and synthesized. The anti-tumor activity results showed that most of the compounds exhibited better anti-proliferative activities than parent compound oridonin, and the most potent compound had an IC₅₀ value of 0.40 μM in K562 cells. Further mechanistic studies revealed that the optimal compound could arrest K562 cells at G2/M phase by inhibiting cdc-2, cdc-25c and cyclin B1 expression. In addition, the optimal compound induced apoptosis in K562 cells through increasing ROS production and depolarizing mitochondrial membrane potential. Collectively, these valuable results suggested that the most potent compound could be an anti-tumor agent candidate and is worthy of further investigation.

Oridonin attenuates hind limb ischemia-reperfusion injury by modulating Nrf2-mediated oxidative stress and NLRP3-mediated inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Oridonin (Ori), extracted from Isodon rubescens (Hemsl.) H.Hara, is a well-known traditional Chinese herbal medicinal product that possesses antioxidant and anti-inflammatory activities. Oxidative stress and inflammation are the main pathophysiological mechanisms in hindlimb IR injury. However, whether Ori has a protective effect on hind limb IR injury is unknown.

AIM OF THE STUDY

The present study was designed to determine the effect of Ori on hindlimb IR injury and its relationship with oxidative stress and inflammation.

MATERIALS AND METHODS

The hind limb IR injury model in mice was used to evaluate the protective effect and related mechanisms of Ori. Forty-eight C57BL/6 mice (n = 12 per group) were randomly divided into four groups: Sham group; IR group; IR + Ori (10 mg/kg) group and IR + Ori (20 mg/kg) group. Mice in the IR and IR + Ori groups were subjected to hindlimb IR injury, while mice in the Sham group were subjected to no hindlimb IR injury. HE staining, Masson's staining, TTC staining, DHE staining, TUNEL staining, western blotting analysis and quantitative real-time PCR were employed to explore the mechanisms by which Ori exerts a protective effect on a classical hindlimb IR model in mice.

RESULTS

We found that Ori pretreatment prevented muscle damage and decreased cell apoptosis levels compared with the vehicle control. Moreover, the SOD2, CAT, MDA and ROS levels in muscle showed that Ori could significantly reduce oxidative stress in hindlimb IR mice, while the IL-1β and TNF-α levels in muscle showed that Ori could significantly attenuate IR-induced inflammation. We also found that Ori could increase the expression of Nrf2 and its downstream protein HO-1 and inhibit the expression levels of NLRP3-related proteins (NLRP3, ASC and Caspase-1) in vivo.

CONCLUSIONS

Our study suggested that Ori has a protective effect on hindlimb IR injury, which may be related to Nrf2-mediated oxidative stress and NLRP3-mediated inflammasome activation.

Anti-inflammatory effects of N-Acetylcysteine and Elaeagnus angustifolia extract on acute lung injury induced by λ-carrageenan in rat

N-Acetylcysteine (NAC) is a chemical compound with anti-inflammatory and antioxidant activity and acts as a free radical scavenger. Elaeagnus angustifolia (EA) is a plant native to the western part of Iran, with antioxidant and anti-inflammatory properties. The present study been taken evaluated the protective effect afforded by EA and NAC extracts on carrageenan-induced acute lung injury in Wistar rats. In this study, 42 rats were randomly assigned into seven groups. NAC and EA extracts were orally administered once/day for 21 continuous days. Pulmonary damage was induced by intratracheal injection of 100 μl of 2% λ-Carrageenan on day 21. Twenty-four hours post-surgery, the rats were euthanized and the samples were collected. Pretreatment with NAC and EA extracts reduced the total and differential cell accumulation as well as IL-6, and TNF-α cytokines. Antioxidant indicators demonstrate that in the groups receiving NAC and EA extract, MDA decreased while thiol and antioxidant capacity elevated. Treatment with NAC and EA significantly reduced Carrageenan-induced pathological pulmonary tissue injury. NAC and EA extract has protective effects on acute carrageenan-induced lung injury.

Leonurine inhibits the TXNIP/NLRP3 and NF-κB pathways via Nrf2 activation to alleviate carrageenan-induced pleurisy in mice

Oxidative stress and inflammation play important roles in pleurisy. Leonurine (Leo) has been confirmed to exert antioxidative and antiinflammatory effects in many preclinical experiments, but these effects have not been studied in pleurisy. The aim of this study was to explore the therapeutic effect and mechanism of Leo in a carrageenan (CAR)-induced pleurisy model. In this study, we found that the increase of reactive oxygen species (ROS), myeloperoxidase (MPO), and malondialdehyde (MDA) and decrease of glutathione (GSH) induced by CAR could be reversed by the treatment of Leo. Leo effectively reduced the levels of proinflammatory cytokines interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), and the percentages of mature macrophages and increased the levels of antiinflammatory cytokines (IL-10). Furthermore, Western blotting revealed that Leo significantly activated the Nrf2 pathway to restrain the thioredoxin-interacting protein/NOD-like receptor protein 3 (TXNIP/NLRP3) and nuclear factor kappa-B (NF-κB) pathways. However, the protective effect of Leo was significantly weakened in Nrf2-deficient mice. These results indicate that Leo confers potent protection against CAR-induced pleurisy by inhibiting the TXNIP/NLRP3 and NF-κB pathways dependent on Nrf2, which may serve as a promising agent for attenuating pleurisy.

Oridonin: A Review of Its Pharmacology, Pharmacokinetics and Toxicity

Oridonin, as a natural terpenoids found in traditional Chinese herbal medicine Isodon rubescens (Hemsl.) H.Hara, is widely present in numerous Chinese medicine preparations. The purpose of this review focuses on providing the latest and comprehensive information on the pharmacology, pharmacokinetics and toxicity of oridonin, to excavate the therapeutic potential and explore promising ways to balance toxicity and efficacy of this natural compound. Information concerning oridonin was systematically collected from the authoritative internet database of PubMed, Elsevier, Web of Science, Wiley Online Library and Europe PMC applying a combination of keywords involving "pharmacology," "pharmacokinetics," and "toxicology". New evidence shows that oridonin possesses a wide range of pharmacological properties, including anticancer, anti-inflammatory, hepatorenal activities as well as cardioprotective protective activities and so on. Although significant advancement has been witnessed in this field, some basic and intricate issues still exist such as the specific mechanism of oridonin against related diseases not being clear. Moreover, several lines of evidence indicated that oridonin may exhibit adverse effects, even toxicity under specific circumstances, which sparked intense debate and concern about security of oridonin. Based on the current progress, future research directions should emphasize on 1) investigating the interrelationship between concentration and pharmacological effects as well as toxicity, 2) reducing pharmacological toxicity, and 3) modifying the structure of oridonin-one of the pivotal approaches to strengthen pharmacological activity and bioavailability. We hope that this review can provide some inspiration for the research of oridonin in the future.

Oridonin interrupts cellular bioenergetics to suppress glioma cell growth by down-regulating PCK2

We aim to evaluate the tumor metabolic suppressive activity of Oridonin (extract of Rabdosia rubescens) in glioma and elucidate its potential mechanism. Effects of Oridonin on U251/U87 cells were determined by CCK8, RTCA, colony formation, flow cytometry, wound healing, and Transwell assay. Xenograft tumor model to evaluate the effect of Oridonin on glioma cells in vivo. Cellular bioenergetics were measured by Seahorse. RNA-seq was performed to screen potential biological pathways in Oridonin treated cells. Bioinformatics analysis of PCK2 in glioma was performed based on TCGA/CGGA. Endogenous PCK2 was knocked-down by lentivirus packaged shRNA. We found Oridonin significantly inhibited cell growth in U251/U87 in vitro and in vivo. Both oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were decreased in Oridonin-treated U251/U87 cells. Oridonin treatment led to PCK2 down-regulation. Additionally, PCK2 was up-regulated in higher grade glioma and correlated with poor outcomes. Furthermore, PCK2 depletion significantly inhibited cell growth and decreased OCR/ECAR in U251/U87 which coincided with the effects of Oridonin. Therefore, we evaluated the potent anti-tumor property of Oridonin in glioma. Importantly, we demonstrated that PCK2 might be a novel target of Oridonin on glioma by inducing energy crisis and increasing oxidative stress.

Medicinal plants and bioactive natural products as inhibitors of NLRP3 inflammasome

The NLR family, pyrin domain-containing 3 (NLRP3) inflammasome is a multiprotein complex that induces caspase-1 activation and the downstream substrates involved with the processing and secretion of the pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18 and tumor necrosis factor-α (TNF- α). The NLRP3 inflammasome is activated by a wide range of danger signals that derive from metabolic dysregulation. Activation of this complex often involves the adaptor ASC and upstream sensors including NLRP1, NLRP3, NLRC4, AIM2, and pyrin, which are activated by different stimuli including infectious agents and changes in cell homeostasis. It has been shown that nutraceuticals and medicinal plants have antiinflammatory properties and could be used as complementary therapy in the treatment of several chronic diseases that are related to inflammation, for example, cardiovascular diseases and diabetes mellitus. Herb-based medicine has demonstrated protective effects against NLRP3 inflammasome activation. Therefore, this review focuses on the effects of nutraceuticals and bioactive compounds derived from medicinal plants on NLRP3 inflammasome activation and the possible mechanisms of action of these natural products. Thus, herb-based, natural products/compounds can be considered novel, practical, and accessible agents in chronic inflammatory diseases by inhibiting NLRP3 inflammasome activation.

Targeting the NLRP3 inflammasome as new therapeutic avenue for inflammatory bowel disease

The incidence and prevalence of inflammatory bowel disease (IBD) are increasing worldwide. Current approved medication for IBD treatment in the clinic mainly includes corticosteroids and neutralization antibodies to pro-inflammatory cytokines. However, drug resistance and severe side effect hinder long-term efficacy of these agents. The NOD-like receptor family pyrin domain containing protein 3 (NLRP3) is exclusively expressed in several inflammatory and autoimmune diseases. Excessive expression, aberrant activation, polymorphism, and gain-of-function mutation of the NLRP3 inflammasome contribute to IBD pathogenesis. In this article, we summarize the regulatory factors to NLRP3, and review recently developed NLRP3 inhibitors and their preclinical and clinical applications in treating inflammatory and autoimmune diseases. We present our views on the therapeutic potential of NLRP3 inhibitors as emerging therapeutic avenue for IBD.

Synthesis and in vitro and in vivo biological evaluation of novel derivatives of flexicaulin A as antiproliferative agents

As our research focuses on anticancer drugs, a series of novel derivatives of flexicaulin A (FA), an ent-kaurene diterpene, condensed with an aromatic ring were synthesized, and their antiproliferative activities against four human cancer cell lines (TE-1, EC109, MCF-7, and MGC-803) were evaluated. The activities of most of the new compounds were better than those of FA. Compound 2y exhibited the best activity with an IC50 value reaching 0.13 μM against oesophageal cancer cells (EC109 cells). The IC50 values for 2y in normal cells (GES-1 cells and HUVECs) were 0.52 μM and 0.49 μM, respectively. Subsequent mechanistic investigations found that compound 2y can inhibit the proliferation of cancer cells and cell cloning. In addition, 2y could reduce the mitochondrial membrane potential, increase the apoptosis rate, and increase the ROS level in EC109 cells. Moreover, 2y can upregulate the expression of ROS/JNK pathway-related proteins (p-ASK1, p-MKK4, p-JNK, and p-Cjun (ser63)) and pro-apoptotic proteins (Bax, Bad, and Bim). In vivo experiments showed that 2y can inhibit tumour growth in nude mice. The mechanism involves an increase in protein expression in the ROS pathway, leading to changes in apoptosis-related proteins. In addition, compound 2y shows low toxicity. These results indicate that compound 2y holds promising potential as an antiproliferative agent.

Promote anti-inflammatory and angiogenesis using a hyaluronic acid-based hydrogel with miRNA-laden nanoparticles for chronic diabetic wound treatment

Chronic diabetic wound causes serious threat to human health due to its long inflammatory phase and the reduced vascularization. Herein, we develop a hydrogel system for the treatment of diabetic wound, which can short the inflammatory stage (through the use of ori) and promote the angiogenesis (through the addition of siRNA-29a gene). Based on the Schiff base bonds, the Gel/Alg@ori/HA-PEI@siRNA-29a hydrogel was prepared by mixing oxidized hydroxymethyl propyl cellulose (OHMPC), adipic dihydrazide-modified hyaluronic acid (HA-ADH), oridonin (ori) loaded alginate microspheres (Alg@ori) and siRNA-29a gene-loading hyaluronic acid-polyethyleneimine complex HA-PEI@siRNA-29a (HA-PEI@siRNA-29a) under physiological conditions, which had moderate mechanical strength, appropriate swelling property, impressive stability, and slow release ability of ori and siRNA-29a. Excellent biocompatibility of the prepared hydrogel was also confirmed by in vitro mouse fibroblasts L929 cells culture study. Moreover, in vivo experiments further demonstrated that the prepared Gel/Alg@ori/HA-PEI@siRNA-29a hydrogel not only significantly accelerated the diabetic wound healing, angiogenesis factors (α-SMA and CD31) production, but also inhibited pro-inflammatory factors (IL-6 and TNF-α). In summary, we believe that the prepared hydrogels exhibit great potential for the treatment of chronic diabetic wound.

Oridonin Attenuates Myocardial Ischemia/Reperfusion Injury via Downregulating Oxidative Stress and NLRP3 Inflammasome Pathway in Mice

Oridonin (ORI), the major pharmacological component extracted from a traditional Chinese medicine, possesses a beneficial effect on myocardial ischemia/reperfusion (I/R) injury. However, the underlying molecular mechanism by which ORI effects take place is not completely known. Thus, whether ORI works via downregulating oxidative stress and nod-like receptor protein-3 (NLRP3) inflammasome pathway was investigated in this study. Mice underwent surgery to induce myocardial I/R injury, and some were administered ORI (10 mg/kg/day) pretreatment, while others were not. The myocardial enzymes' levels, infarct area, and inflammatory injury were measured. The activation situation of oxidative stress and NLRP3 inflammasome was also detected. We found that ORI pretreatment significantly alleviated CK-MB and cTnI levels and infarct size induced by I/R. ORI mitigated the inflammatory injury by decreasing the pathological damage and lowering TNF-α, IL-1β, and IL-18 levels. Moreover, the SOD1 and eNOS levels were significantly increased by ORI, while MDA and iNOS levels were relatively decreased. The oxidative stress was reversed using ORI pretreatment. Importantly, NLRP3 inflammasome pathway was also inhibited by ORI, as reflected by the lower protein levels of NLRP3, caspase-1, and IL-1β. In conclusion, ORI alleviates myocardial injury induced by I/R via inhibiting the oxidative stress and NLRP3 inflammasome pathway.

Pterostilbene prevents LPS-induced early pulmonary fibrosis by suppressing oxidative stress, inflammation and apoptosis in vivo

Early pulmonary fibrosis after acute lung injury leads to poor prognosis and high mortality. Pterostilbene (Pts), a bioactive component in blueberries, possesses anti-inflammatory, antioxidative and antifibrotic properties. However, the effects of Pts on lipopolysaccharide (LPS)-induced pulmonary fibrosis are still unknown. In our study, the Pts group showed lower lung injury and fibrosis scores, and lower levels of hydroxyproline and protein (collagen I and transforming growth factor-β) than the scores and levels in mice treated with LPS. MMP-1 was the degrading enzyme of collagen I and LPS caused the inhibition of MMP-1, disturbing the degradation of collagen. Additionally, Pts remarkably reversed the LPS-induced inhibition of interleukin-10 and the release of tumor necrosis factor-α, interleukin-6 and interleukin-1β. In terms of cellular pathways, Pts treatment ameliorated LPS-activated nuclear factor kappa B (NF-κB) and NOD-like receptor NLRP3 signaling. Besides, LPS-induced low levels of A20 could be activated by Pts. In addition, Pts treatment reversed the high levels of Caspase-3, poly ADP-ribose polymerase (PARP) and Bcl2-associated X protein (Bax) expression and the low levels of B cell lymphoma/lewkmia-2 (Bcl2) that had been induced by LPS. Moreover, oxidative stress is also involved in the pathogenesis of fibrosis. Our findings indicate that LPS injection triggered the production of myeloperoxidase (MPO) and malondialdehyde (MDA) and the depletion of superoxide dismutase (SOD) and glutathione (GSH), and that these effects were notably reversed by treatment with Pts. In addition, Pts induced the dissociation of Kelch-like epichlorohydrin-associated protein-1 (Keap-1) and NF-E2 related factor-2 (Nrf2) and the activation of downstream genes (heme oxygenase-1, NAD(P)H:quinine oxidoreductase, glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase modifier). In conclusion, oxidative stress, apoptosis and inflammation are involved in early pulmonary fibrosis and Pts exerts a protective effect by activating Keap-1/Nrf2, inhibiting caspase-dependent A20/NF-κB and NLRP3 signaling pathways.

Involvement of Nucleotide-Binding Oligomerization Domain-Like Receptor Family Pyrin Domain Containing 3 Inflammasome in the Pathogenesis of Liver Diseases

The inflammasome is widely acknowledged for its crucial role in the pathogenesis of cancers and many neurodegenerative, metabolic, and auto-inflammatory diseases in recent years. Multiple types of inflammasomes exist. However, nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is the most often investigated inflammasome and has come to limelight in recent studies. NLRP3 inflammasome is a multi-protein complex. Its activation can cause the cleavage of inactive pro-caspase-1 into activated caspase-1, that ultimately promotes the transformation of pro-interleukin (IL)-1β and pro-IL-18 into biologically-active IL-1β and IL-18, respectively. These processes lead to the local inflammatory responses and induce pyroptosis, causing disparaging effects. Recently, numerous studies have shown that NLRP3 inflammasome plays an important role in the pathogenesis of liver diseases, including non-alcoholic fatty liver disease, liver fibrosis, cirrhosis, and hepatocellular carcinoma. Liver diseases have become a severe health burden worldwide, and there is adequate evidence indicating that the regulation of NLRP3 inflammasome acts as a guard against hazard to liver. In this review, we provide a straightforward overview of NLRP3 inflammasome as well as several frequent liver diseases. We then discuss the contribution and regulation of NLRP3 inflammasome during the pathogenesis of liver diseases, which may provide an important indication for the prevention and treatment of various liver diseases.