Kinsenoside screening with a microfluidic chip attenuates gouty arthritis through inactivating NF-κB signaling in macrophages and protecting endothelial cells

Ruscogenin attenuates osteoarthritis by modulating oxidative stress-mediated macrophage reprogramming via directly targeting Sirt3

BACKGROUND

Synovial inflammation, Cartilage erosion, and subchondral osteosclerosis, which are collectively referred to as the triad of pathogenesis, contribute to osteoarthritis (OA) progression. Specifically, the M1 macrophage in the synovium worsens the development of the illness and is a significant factor in the deterioration and functioning of cartilage.

OBJECTIVE

To investigate whether Ruscogenin attenuates progressive degeneration of articular cartilage in rats with anterior cruciate ligament transection (ACLT)-induced osteoarthritis (OA) by modulating macrophage reprogramming and to explore its specific mechanism of action.

METHODS

In vitro, SW1353 cells and RAW264.7 cells were applied to elucidate the mechanisms by which Ruscogenin protects articular cartilage. Specifically, the expression levels of molecules related to cartilage ECM synthesis and degradation enzymes and macrophages were analysed. In vivo, a rat osteoarthritis model was established using ACLT. The protective effect of Ruscogenin on articular cartilage was observed.

RESULTS

Ruscogenin significantly reversed LPS-induced macrophage inflammatory response and promoted cartilage regeneration-related factors. In addition, Ruscogenin had a significant protective effect on the knee joint of ACLT rats, effectively preventing cartilage degeneration. These positive therapeutic effects were achieved on the one hand by Ruscogenin regulating macrophage reprogramming by targeting Sirt3, and on the other hand Ruscogenin could attenuate the ROS level of chondrocytes thereby inhibiting chondrocyte ferroptosis.

CONCLUSIONS

Ruscogenin exerts chondroprotective effects by regulating macrophage reprogramming and inhibiting chondrocyte ferroptosis.

Lab-on-a-chip: an advanced technology for the modernization of traditional Chinese medicine

Benefiting from the complex system composed of various constituents, medicament portions, species, and places of origin, traditional Chinese medicine (TCM) possesses numerous customizable and adaptable efficacies in clinical practice guided by its theories. However, these unique features are also present challenges in areas such as quality control, screening active ingredients, studying cell and organ pharmacology, and characterizing the compatibility between different Chinese medicines. Drawing inspiration from the holistic concept, an integrated strategy and pattern more aligned with TCM research emerges, necessitating the integration of novel technology into TCM modernization. The microfluidic chip serves as a powerful platform for integrating technologies in chemistry, biology, and biophysics. Microfluidics has given rise to innovative patterns like lab-on-a-chip and organoids-on-a-chip, effectively challenging the conventional research paradigms of TCM. This review provides a systematic summary of the nature and advanced utilization of microfluidic chips in TCM, focusing on quality control, active ingredient screening/separation, pharmaceutical analysis, and pharmacological/toxicological assays. Drawing on these remarkable references, the challenges, opportunities, and future trends of microfluidic chips in TCM are also comprehensively discussed, providing valuable insights into the development of TCM.

Virtual screening combined with experimental verification reveals the potential mechanism of Fuzitang decoction against Gouty Arthritis

Background

and Purpose: Fuzitang decoction (FZT), a classic prescription of traditional Chinese medicine (TCM), has excellent efficacy in treating gouty arthritis (GA). However, the underlying molecular mechanism remains obscure. In the present study, we aimed to explore the underlying mechanisms of FZT in treating GA by virtual screening combined with experimental verification.

Methods

In this study, the active components of FZT and their corresponding targets were screened from the TCMSP database and TargetNet database. Then, the potential targets of FZT against GA were retrieved from multiple databases to generate a network. Protein-protein interaction, herbal-component-target, Gene Ontology (GO) enrichment, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were applied to identify potential targets and related signaling pathways. Furthermore, molecular docking simulation was applied to identify the interactions between the drug and targets. Finally, in vitro experiments were conducted to validate the potential targets and signaling pathways.

Results

In the present study, several crucial components, including kaempferol, luteolin, catechin, deoxyandrographolide, and perlolyrine in FZT, were obtained through network pharmacology, and several potential targets to treat GA were developed, such as PPARG, CYP3A4, PTGS2 (known as COX2), VEGFA, and CYP1A1. Experimental validation suggested that deoxyandrographolide significantly suppressed the expression of IL-1β, COX2, NLRP3 and IL-6 in inflammatory monocyte cells.

Conclusions

Our results identified a novel anti-inflammatory compound, deoxyandrographolide, which helps to explain the potential mechanism of FZT in treating GA and provides evidence to support FZT's clinical use.

The dysregulation of immune cells induced by uric acid: mechanisms of inflammation associated with hyperuricemia and its complications

Changes in lifestyle induce an increase in patients with hyperuricemia (HUA), leading to gout, gouty arthritis, renal damage, and cardiovascular injury. There is a strong inflammatory response in the process of HUA, while dysregulation of immune cells, including monocytes, macrophages, and T cells, plays a crucial role in the inflammatory response. Recent studies have indicated that urate has a direct impact on immune cell populations, changes in cytokine expression, modifications in chemotaxis and differentiation, and the provocation of immune cells by intrinsic cells to cause the aforementioned conditions. Here we conducted a detailed review of the relationship among uric acid, immune response, and inflammatory status in hyperuricemia and its complications, providing new therapeutic targets and strategies.

A comprehensive review on pharmacological, toxicity, and pharmacokinetic properties of phillygenin: Current landscape and future perspectives

Forsythiae Fructus is a traditional Chinese medicine frequently in clinics. It is extensive in the treatment of various inflammation-related diseases and is renowned as 'the holy medicine of sores'. Phillygenin (C21H24O6, PHI) is a component of lignan that has been extracted from Forsythiae Fructus and exhibits notable biological activity. Modern pharmacological studies have confirmed that PHI demonstrates significant activities in the treatment of various diseases, including inflammatory diseases, liver diseases, cancer, bacterial infection and virus infection. Therefore, this review comprehensively summarizes the pharmacological effects of PHI up to June 2023 by searching PubMed, Web of Science, Science Direct, CNKI, and SciFinder databases. According to the data, PHI shows remarkable anti-inflammatory, antioxidant, hepatoprotective, antitumour, antibacterial, antiviral, immunoregulatory, analgesic, antihypertensive and vasodilatory activities. More importantly, NF-κB, MAPK, PI3K/AKT, P2X7R/NLRP3, Nrf2-ARE, JAK/STAT, Ca2+-calcineurin-TFEB, TGF-β/Smads, Notch1 and AMPK/ERK/NF-κB signaling pathways are considered as important molecular targets for PHI to exert these pharmacological activities. Studies of its toxicity and pharmacokinetic properties have shown that PHI has very low toxicity, incomplete absorption in vivo and low oral bioavailability. In addition, the physico-chemical properties, new formulations, derivatives and existing challenges and prospects of PHI are also reviewed and discussed in this paper, aiming to provide direction and rationale for the further development and clinical application of PHI.

Targeting macrophage polarization as a promising therapeutic strategy for the treatment of osteoarthritis

Osteoarthritis (OA) is a chronic osteoarthropathy characterized by the progressive degeneration of articular cartilage and synovial inflammation. Early OA clinical treatments involve intra-articular injection of glucocorticoids, oral acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), which are used for anti-inflammation and pain relief. However, long-term use of these agents will lead to inevitable side effects, even aggravate cartilage loss. At present, there are no disease-modifying OA drugs (DMOADs) yet approved by regulatory agencies. Polarization regulation of synovial macrophages is a new target for OA treatment. Inhibiting M1 polarization and promoting M2 polarization of synovial macrophages can alleviate synovial inflammation, relieve joint pain and inhibit articular cartilage degradation, which is a promising strategy for OA treatment. In this study, we describe the molecular mechanisms of macrophage polarization and its key role in the development of OA. Subsequently, we summarize the latest progress of strategies for OA treatment through macrophage reprogramming, including small molecule compounds (conventional western medicine and synthetic compounds, monomer compounds of traditional Chinese medicine), biomacromolecules, metal/metal oxides, cells, and cell derivatives, and interprets the molecular mechanisms, hoping to provide some information for DMOADs development.

Advances in the therapeutic application and pharmacological properties of kinsenoside against inflammation and oxidative stress-induced disorders

Extensive research has implicated inflammation and oxidative stress in the development of multiple diseases, such as diabetes, hepatitis, and arthritis. Kinsenoside (KD), a bioactive glycoside component extracted from the medicinal plant Anoectochilus roxburghii, has been shown to exhibit potent anti-inflammatory and anti-oxidative abilities. In this review, we summarize multiple effects of KD, including hepatoprotection, pro-osteogenesis, anti-hyperglycemia, vascular protection, immune regulation, vision protection, and infection inhibition, which are partly responsible for suppressing inflammation signaling and oxidative stress. The protective action of KD against dysfunctional lipid metabolism is also associated with limiting inflammatory signals, due to the crosstalk between inflammation and lipid metabolism. Ferroptosis, a process involved in both inflammation and oxidative damage, is potentially regulated by KD. In addition, we discuss the physicochemical properties and pharmacokinetic profiles of KD. Advances in cultivation and artificial synthesis techniques are promising evidence that the shortage in raw materials required for KD production can be overcome. In addition, novel drug delivery systems can improve the in vivo rapid clearance and poor bioavailability of KD. In this integrated review, we aim to offer novel insights into the molecular mechanisms underlying the therapeutic role of KD and lay solid foundations for the utilization of KD in clinical practice.

Calycosin represses AIM2 inflammasome-mediated inflammation and pyroptosis to attenuate monosodium urate-induced gouty arthritis through NF-κB and p62-Keap1 pathways

Gouty arthritis is an inflammatory disease induced by monosodium urate (MSU), and is closely related to the activation of inflammasomes. Calycosin plays an anti-inflammatory role in arthritis. This study explored the mechanism of Calycosin in MSU-induced gouty arthritis. MSU-induced gouty arthritis mouse models with or without treatment of Calycosin were established, and physiological and pathological indicators were determined. Similarly, peripheral blood mononuclear cells (PBMCs) and THP-1 macrophages were used in vitro. Lactate dehydrogenase (LDH) was tested. The degree of centrifugal infiltration was detected by immunofluorescence. ELISA and quantitative reverse-transcription polymerase chain reaction were conducted to determine the levels of inflammatory factors. Immunohistochemistry, immunofluorescence, and flow cytometry were utilized to detect the content of caspase-1. Protein expressions of NF-κB-, p62-Keap1 pathway-, and pyroptosis-related factors were examined by western blot. In MSU-induced mouse models, calycosin increased mechanical hyperalgesia but decreased the swelling index of the mouse knee joint in a time-dependent manner. MSU treatment increased inflammatory cells and LysM-eGFP⁺ neutrophils recruitment in vivo, and promoted the LDH content in vitro, and meanwhile, calycosin reversed the aforementioned effects of MSU. In addition, calycosin repressed the release of inflammatory factors, promoted p62 level and diminished the levels of AIM2, caspase-1, ASC, IL-1β, Keap1, Cleaved GSDMD, and Cleaved caspase-1 and phosphorylation of p65 and IκBα in MSU-induced mouse or cell models. Furthermore, AIM2 silencing also inhibited MSU-induced inflammation and pyroptosis. Collectively, calycosin may inhibit AIM2 inflammasomes-mediated inflammation and pyroptosis through NF-κB and p62-Keap1 pathways, ultimately playing a protective role in gouty arthritis.

Kinsenoside alleviates inflammation and fibrosis in experimental NASH mice by suppressing the NF-κB/NLRP3 signaling pathway

BACKGROUND

Non-alcoholic steatohepatitis (NASH) has replaced viral hepatitis as the main driver of the rising morbidity and mortality associated with cirrhosis and liver cancer worldwide, while no FDA-approved therapies are currently known. Kinsenoside (KD), naturally isolated from Anoectochilus roxburghii, possesses multiple biological activities, including lipolysis, anti-inflammation, and hepatoprotection. However, the effects of KD on NASH remain unclear.

PURPOSE

This study aimed to explore the roles of KD in NASH and its engaged mechanisms.

METHODS

Two typical animal models of NASH, mice fed a methionine-choline-deficient (MCD) diet (representing non-obese NASH) and mice fed a high-fat and -fructose diet (HFFD) (representing obese NASH), were used to investigate the effect of KD on NASH in vivo. Transcriptome sequencing was performed to elucidate the underlying mechanisms of KD. Lipopolysaccharide (LPS)-stimulated THP-1 cells and transforming growth factor β1 (TGF-β1)-activated LX-2 cells were applied to further explore the effects and mechanisms of KD in vitro.

RESULTS

The intragastric administration of KD remarkably alleviated MCD/HFFD-induced murine NASH almost in a dose-dependent manner. Specifically, KD reduced lipid accumulation, inflammation, and fibrosis in the liver of NASH mice. KD ameliorated alanine aminotransferase (ALT), aspartate aminotransferase (AST), superoxide dismutase (SOD), and malondialdehyde (MDA) abnormalities. In addition, it decreased the level of serum proinflammatory factors (IL-12p70, IL-6, TNF-α, MCP-1, IFN-γ) and the hepatic expression of typical fibrosis-related molecules (α-SMA, Col-I, TIMP-1). Mechanically, KD attenuated the MCD/HFFD-induced NASH through the inhibition of the NF-κB/NLRP3 signaling pathway. Consistently, KD reduced inflammation stimulated by LPS in THP-1 cells via suppressing the NF-κB/NLRP3 pathway. Furthermore, it prevented the activation of LX-2 cells directly, by inhibiting the proliferation stimulated by TGF-β1, and indirectly, by inactivating the NLRP3 inflammasome in macrophages.

CONCLUSION

For the first time, the practical improvement of NASH by KD was revealed. Our study found that KD exerted its alleviative effects on NASH through the inhibition of the NF-κB/NLRP3 signaling pathway. Given its hepatoprotective and nontoxic properties, KD has the potential to be a novel and effective drug to treat NASH.

Cynarin suppresses gouty arthritis induced by monosodium urate crystals

The study is aimed to determine the effects of cynarin (Cyn) on mice with gouty arthritis (GA) induced by monosodium urate (MSU). We measured swelling in the hind paws of mice in vivo using Vernier calipers and ultrasound. The liver, kidney, and hind paws were stained with hematoxylin-eosin, and M1 type macrophages were detected in the hind paws using anti-F4/80 and anti-iNOS antibodies. The mRNA expression of inflammatory factors in bone marrow-derived macrophages (BMDMs) and in the hind paws was detected via quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasomes and the nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) pathways were analyzed via western blotting. Cyn was detected in vitro using Cell Counting Kit-8 (CCK-8). Cyn treatment reduced hind paw swelling and M1 macrophage infiltration, suppressed the mRNA expression of inflammatory factors, and inhibited NLRP3 inflammasome activation in vivo, in addition to inhibiting the phosphorylation of IKKa/β, p65, and c-Jun NH 2-terminal kinase (JNK). Furthermore, Cyn exerted anti-inflammatory and anti-swelling effects in mice with GA by regulating the NF-κB and JNK pathways and NLRP3 inflammasomes.

Influence of Pinealectomy and Long-term Melatonin Administration on Inflammation and Oxidative Stress in Experimental Gouty Arthritis

Gout is an inflammatory arthritis characterized by the deposition of monosodium urate (MSU) crystals in the joints or soft tissue. MSU crystals are potent inflammation inducers. Melatonin (MLT) is a powerful endogenous anti-inflammatory agent and effective in reducing cellular damage. In the present study, possible underlying mechanisms associated with anti-inflammatory and antioxidative effects were investigated in rats with gouty arthritis and melatonin deprivation treated with MLT. Fifty-six rats were divided into seven groups: control, sham control, pinealectomy (PNX), MSU (on the 30th day, single-dose 20 mg/ml, intraperitoneal), MSU + MLT (10 mg/kg/day for 30 days, intraperitoneal), MSU + PINX and MSU + PINX + MLT. PNX procedure was performed on the first day of the study. As compared to the controls, the results showed that MSU administration caused significant increases in oxidative stress parameters (malondialdehyde and total oxidant status). Besides, significant decreases in antioxidant defense systems (glutathione, superoxide dismutase and total antioxidant status) were observed. A statistically significant increase was found in the mean histopathological damage score in the groups that received MSU injection. It was found that histopathological changes were significantly reduced in the MSU + MLT group given MLT. In our study, it was determined that many histopathological changes, as well as swelling and temperature increase in the joint, which are markers of inflammation, were significantly reduced with MLT supplementation. These results suggest that melatonin ameliorates MSU-induced gout in the rat through inhibition of oxidative stress and proinflammatory cytokine production.

In vitro and in vivo ameliorative effects of polyphenols from purple potato leaves on renal injury and associated inflammation induced by hyperuricemia

In the present study, the ameliorative effects of polyphenols from purple potato leaves (PSPLP) on hyperuricemia were investigated. HPLC-MS analysis showed that PSPLP was mainly composed of caffeoylquinic acid derivatives (84%). PSPLP inhibited the levels of cytokines (IL-1β, IL-6, and TNF-α) in monosodium urate-induced RAW264.7 cells. In vivo, PSPLP significantly inhibited the level of uric acid in hyperuricemia mice from 209.6 to 166.6 μM, and significantly interfered with the activities of xanthine oxidase (XOD) and adenosine deaminase in liver, the activity of XOD decreased from 13.5 to 11.6 U/gprot. PSPLP can decrease serum creatinine level from 105 to 59 μM, and urea nitrogen level from 21.9 to 14.1 mM, which can effectively protect kidney. These results provide a reference for future research and application of PSPLP as a functional food to intervene hyperuricemia and associated inflammation. PRACTICAL APPLICATIONS: This study evaluated the effect of polyphenols from purple potato leaves (PSPLP) on hyperuricemia. The results suggested that PSPLP has an important role in the intervention of hyperuricemia and hyperuricemic-related inflammation or renal injury, and can be used in the application of functional foods. These results provided a basis for further study on the biological activities of polyphenols from purple sweet potato leaves.

Circular RNA circHIPK3 Activates Macrophage NLRP3 Inflammasome and TLR4 Pathway in Gouty Arthritis via Sponging miR-561 and miR-192

Increasing evidences indicate that circular RNAs (circRNAs) play important roles in regulating gene expressions in various diseases. However, the role of circRNAs in inflammatory response of gouty arthritis remains unknown. This study aims to investigate the role and underlying mechanism of circHIPK3 in inflammatory response of gouty arthritis. Quantitative real-time PCR was used to detect the expressions of circHIPK3, miR-192 and miR-561. Western blot was used to detect the protein levels of TLR4, NLRP3, nuclear factor-κB (NF-κB) related proteins, and Caspase-1. Dual luciferase reporter assay, RNA pull-down assay, and FISH assay were used to confirm the interaction between circHIPK3 and miR-192/miR-561. ELISA was used to detect interleukin (IL)-1β and tumor necrosis factor (TNF)-α levels. circHIPK3 was elevated in synovial fluid mononuclear cells (SFMCs) from patients with gouty arthritis and monosodium urate (MSU)-stimulated THP-1 cells. circHIPK3 overexpression promoted the inflammatory cytokines levels in MSU-stimulated THP-1 cells, and circHIPK3 silencing obtained the opposite effect. Mechanistically, circHIPK3 sponged miR-192 and miR-561, and subsequently promoted the expressions of miR-192 and miR-561 target gene TLR4 and NLRP3. In vivo experiments confirmed circHIPK3 knockdown suppressed gouty arthritis. circHIPK3 sponges miR-192 and miR-561 to promote TLR4 and NLRP3 expressions, thereby promoting inflammatory response in gouty arthritis.

A review of pharmacological and pharmacokinetic properties of Forsythiaside A

Traditional Chinese medicine plays a significant role in the treatment of various diseases and has attracted increasing attention for clinical applications. Forsythiae Fructus, the dried fruit of Forsythia suspensa (Thunb.) Vahl, is a widely used Chinese medicinal herb in clinic for its extensive pharmacological activities. Forsythiaside A is the main active index component isolated from Forsythiae Fructus and possesses prominent bioactivities. Modern pharmacological studies have confirmed that Forsythiaside A exhibits significant activities in treating various diseases, including inflammation, virus infection, neurodegeneration, oxidative stress, liver injury, and bacterial infection. In this review, the pharmacological activities of Forsythiaside A have been comprehensively reviewed and summarized. According to the data, Forsythiaside A shows remarkable anti-inflammation, antivirus, neuroprotection, antioxidant, hepatoprotection, and antibacterial activities through regulating multiple signaling transduction pathways such as NF-κB, MAPK, JAK/STAT, Nrf2, RLRs, TRAF, TLR7, and ER stress. In addition, the toxicity and pharmacokinetic properties of Forsythiaside A are also discussed in this review, thus providing a solid foundation and evidence for further studies to explore novel effective drugs from Chinese medicine monomers.

Kinsenoside Alleviates 17α-Ethinylestradiol-Induced Cholestatic Liver Injury in Rats by Inhibiting Inflammatory Responses and Regulating FXR-Mediated Bile Acid Homeostasis

Cholestasis is an important predisposing factor of liver diseases, such as hepatocyte necrosis, liver fibrosis and primary biliary cirrhosis. In this study, we aimed to investigate the effects of Kinsenoside (KD), a natural active ingredient of Anoectochilus roxburghii, on estrogen-induced cholestatic liver injury in Sprague-Dawley rats and the underlying mechanism. The rats were randomly divided into six groups: control group, model group, low-dose KD group (50 mg/kg body weight, KD-L), medium-dose KD group (100 mg/kg body weight, KD-M), high-dose KD group (200 mg/kg body weight, KD-H) and ursodeoxycholic acid group (40 mg/kg body weight, UDCA). 17α-Ethinylestradiol (EE) was used to establish an experimental animal model of estrogen-induced cholestasis (EIC). The results demonstrated that KD alleviated liver pathologic damage, serum biochemical status and inhibited hepatocellular microstructure disorder and bile duct hyperplasia in EE-induced cholestatic rats. Mechanically, KD alleviated EE-induced cholestatic liver injury by inhibiting inflammatory responses and regulating bile acid homeostasis. Concretely, KD reduced the expression of IL-1β and IL-6 by inhibiting NF-κB p65 to suppress EE-mediated inflammation in rat liver. KD enhanced the expression of FXR and inhibited EE-mediated reduction of FXR in vitro and in vivo. It was the potential mechanism that KD mitigates cholestasis by increasing efflux and inhibiting uptake of bile acids via FXR-mediated induction of bile salt export pump (BSEP) and reduction of Na⁺-dependent taurocholate cotransport peptide (NTCP) to maintain bile acid homeostasis. Moreover, KD repressed the bile acid synthesis through reducing the expression of synthetic enzyme (CYP7A1), thereby normalizing the expression of metabolic enzyme (SULT2A1) of bile acid. In conclusion, our results revealed that KD may be an effective drug candidate for the treatment of cholestasis.

Purification, structure and conformation characterization of a novel glucogalactan from Anoectochilus roxburghii

Anoectochilus roxburghii (AR) has been used in food, medicine and ornamental industries for a long time. Anion exchange resin was proposed to purify the sub-fraction of water-extracted AR polysaccharide (ARPP-70), and a homogeneous polysaccharide ARPP-70a was obtained. The structural features of ARPP-70a were characterized using gas chromatography-mass spectrometry (GC-MS), nuclear magnetic resonance (NMR) spectroscopy, and high performance size exclusion chromatograph coupled with multi-angle laser light scattering (HPSEC-MALLS). The relative weight average molecular weight for ARPP-70a was determined to be 14.8 kDa, and the molar ratio of glucose to galactose was 1.0:3.2. The structure of ARPP-70a was elucidated to be glucogalactan, with backbone comprising β-1,4-linked Galp and some α-1,4-linked Glcp. The conformation characteristics of ARPP-70a were supposed to exist as a random coil chain in 0.1 M NaNO₃ solution. Moreover, in vitro antioxidant activity assays revealed ARPP-70a exhibited appreciable antioxidant potential. To the best of our knowledge, this is the first study to obtain this type of glucogalactan, and provide systematic information on its structural and conformational properties. This study improved the understanding of the physicochemical characteristics of AR polysaccharide, which is beneficial for its further application in food and medicinal industry.

Cichoric Acid Ameliorates Monosodium Urate-Induced Inflammatory Response by Reducing NLRP3 Inflammasome Activation via Inhibition of NF-kB Signaling Pathway

Gouty arthritis is characterized by the deposition of monosodium urate (MSU) within synovial joints and tissues due to increased urate concentrations. Here, we elucidated the role of the natural compound cichoric acid (CA) on the MSU crystal-stimulated inflammatory response. The THP-1-derived macrophages (THP-Ms) were pretreated with CA and then stimulated with MSU suspensions. The protein levels of p65 and IκBα, the activation of the NF-κB signaling pathway by measuring the expression of its downstream inflammatory cytokines, and the activity of NLRP3 inflammasome were measured by western blotting and ELISA. CA treatment markedly inhibited the degradation of IκBα and the activation of NF-κB signaling pathway and reduced the levels of its downstream inflammatory genes such as IL-1β, TNF-α, COX-2, and PGE2 in the MSU-stimulated THP-M cells. Therefore, we infer that CA effectively alleviated MSU-induced inflammation by suppressing the degradation of IκBα, thereby reducing the activation of the NF-κB signaling pathway and the NLRP3 inflammasome. These results suggest that CA could be a novel therapeutic strategy in averting acute episodes of gout.

Roles of Interactions Between Toll-Like Receptors and Their Endogenous Ligands in the Pathogenesis of Systemic Juvenile Idiopathic Arthritis and Adult-Onset Still's Disease

Systemic juvenile idiopathic arthritis (JIA) and adult-onset Still’s disease (AOSD) are systemic inflammatory disorders that manifest as high-spiking fever, joint pain, evanescent skin rash, and organomegaly. Their pathogenesis is unclear, but inflammation is triggered by activation of the innate immune system with aberrant production of proinflammatory cytokines. Along with extrinsic factors, intrinsic pathways can trigger an unexpected immune response. Damage-associated molecular patterns (DAMPs) induce the activation of innate immune cells, leading to sterile inflammation in systemic JIA and AOSD. These endogenous proteins interact with Toll-like receptors (TLRs), which are pattern recognition receptors, and mediate immune signaling following stimulation by pathogen-associated molecular patterns and DAMPs. Several DAMPs, such as S100 proteins, play a role in the development or severity of systemic JIA and AOSD, in which their interactions with TLRs are altered. Also, the expression levels of genes encoding DAMPs contribute to the susceptibility to systemic JIA and AOSD. Herein, we review reports that TLR and DAMP signaling initiates and/or maintains the inflammatory response in systemic JIA and AOSD, and their correlations with the clinical characteristics of those diseases. In addition, we assess their utility as biomarkers or therapeutics for systemic JIA and AOSD.

Targeting BRD4 prevents acute gouty arthritis by regulating pyroptosis

Background: Acute gouty arthritis is a common inflammatory arthropathy resulting from urate deposition in joints during persistent hyperuricemia. Nevertheless, effective therapeutic strategies are still unavailable. Here, we propose the crucial role of bromodomain-containing protein 4 (BRD4) in acute gouty arthritis.

Methods: Therapeutic effect of BRD4 specific inhibitor JQ-1 on acute gouty arthritis was evaluated in vivo and in vitro. Pyroptosis was analyzed by Caspase-1/PI double staining and cleavage of gasdermin D (GSDMD). Expression of key factors involved in BRD4/NF-κB/NLRP3/GSDMD signaling pathway were measured by western blot, and colocalization of NLRP3 and ASC was detected using immunofluorescence. In addition, the role of BRD4 on monosodium uric acid crystals (MSU)-induced pyroptosis was verified in BRD4 siRNA-transfected THP-1 cells.

Results: Pretreatment of JQ1 and BRD4 siRNA significantly suppressed pyroptosis and inhibited activation of p65 NF-κB signaling as well as NLRP3 inflammasome in THP-1 cells exposed to MSU. In vivo, JQ-1 administration could effectively attenuate joint swelling and synovial inflammation in rats treated by intra-articular injection of MSU. More importantly, MSU led to macrophage pyroptosis and Brd4/NF-κB/NLRP3/GSDMD signaling induction in rat synoviums, which was improved by JQ-1.

Conclusions: Our study identifies the role of BRD4 in MSU-induced pyroptosis through regulating NF-κB/NLRP3/GSDMD signaling pathways, which provides a potential target for treatment of acute gouty arthritis.

Anti-inflammatory and anti-gouty-arthritic effect of free Ginsenoside Rb1 and nano Ginsenoside Rb1 against MSU induced gouty arthritis in experimental animals

Ginsenoside Rb1 (GsRb1) is the best constituent of ginseng and although it shows clinical efficacy as an antineoplastic, antioxidative and antirheumatic agent, its oral bioavailability is poor due to its limited solubility. In this study, the solubility of GsRb1 was improved by encapsulating it in polymeric nanocapsules (encapsulation efficiency: 99.79%), therefore, improving the oral bioavailability. The encapsulation resulted in stable, homogenous and well-dispersed nano-GsRb1, whose mean particle size and zeta potential were 183.9 nm and +36.9 mV, respectively. A significant improvement was observed in the in vitro release profile of nano-GsRb1 as compared to its free form. Our study also indicated a significant repression of the degradation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha (IκBα), the nuclear factor kappa B (NF-κB) signaling pathway, NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome activation, and the mitochondrial damage, thereby, reducing inflammation and gouty arthritis induced by monosodium urate (MSU), when compared to free GsRb1, strongly suggesting that polymeric nano-particles can be a novel approach for delivering the GsRb1 into the inflamed joints for a better treatment effectiveness.

Efficient Drug Screening and Nephrotoxicity Assessment on Co-culture Microfluidic Kidney Chip

The function and susceptibility of various drugs are tested with renal proximal tubular epithelial cells; yet, replicating the morphology and kidneys function using the currently available in vitro models remains difficult. To overcome this difficulty, in the study presented in this paper, a device and a three-layer microfluidic chip were developed, which provides a simulated environment for kidney organs. This device includes two parts: (1) microfluidic drug concentration gradient generator and (2) a flow-temperature controlled platform for culturing of kidney cells. In chip study, renal proximal tubular epithelial cells (RPTECs) and peritubular capillary endothelial cells (PCECs) were screened with the drugs to assess the drug-induced nephrotoxicity. Unlike cells cultured in petri dishes, cells cultured in the microfluidic device exhibited higher performance in terms of both cell growth and drug nephrotoxicity evaluation. It is worth mentioning that a significant decrease in cisplatin-induced nephrotoxicity was found because of the intervention of cimetidine in the microfluidic device. In conclusion, the different in the cell performance between the microfluidic device and the petri dishes demonstrates the physiological relevance of the nephrotoxicity screening technology along with the microfluidic device developed in this study. Furthermore, this technology can also facilitate the development of reliable kidney drugs and serve as a useful and efficient test-bed for further investigation of the drug nephrotoxicity evaluation.

Metformin Inhibits Proliferation of Human Thyroid Cancer TPC-1 Cells by Decreasing LRP2 to Suppress the JNK Pathway

Objective

To uncover the potential effect of metformin on proliferation and apoptosis of thyroid cancer TPC-1 cell line, and the underlying mechanism.

Methods

Viability, apoptosis and LRP2 level in TPC-1 cells treated with different doses of metformin for different time points were determined. Besides, protein levels of p-JNK1 and c-Jun N-terminal kinases (JNK) in metformin-treated TPC-1 cells were detected by Western blot. Regulatory effects of LRP2 on the JNK pathway and cell viability in metformin-treated TPC-1 cells were assessed.

Results

Viability in TPC-1 cells gradually decreased with the treatment of increased doses of metformin either for 24 h or 48 h. The apoptotic rate was concentration-dependently elevated by metformin treatment. Relative levels of LRP2 and p-JNK1 were concentration-dependently downregulated by metformin treatment. In addition, overexpression of LRP2 partially abolished the inhibitory effect of metformin on the viability of TPC-1 cells.

Conclusion

Metformin treatment suppresses the proliferative ability and induces apoptosis of TPC-1 cells by downregulating LRP2 to block the JNK pathway.

Proanthocyanidins attenuate breast cancer-induced bone metastasis by inhibiting Irf-3/c-jun activation

We have previously demonstrated the pivotal role of Jnk-mediated Irf-3/c-Jun in regulating nuclear factor kappa-Β ligand (RANKL)-induced osteoclastogenesis. Here, we demonstrated that proanthocyanidins (PACs) target Irf-3 to alleviate breast cancer-induced activation of osteoclasts. We also found that PACs induced apoptosis of osteoclast precursors by upregulating the ratio of bax/bcl-2 and activating caspase-3 activity. Such bone protective effect also could be observed in a bone metastasis model of breast cancer. These findings provided a novel therapeutic intervention targeting abnormal bone metabolism to alleviate bone metastasis of breast cancer.

Kinsenoside ameliorates intervertebral disc degeneration through the activation of AKT-ERK1/2-Nrf2 signaling pathway

Intervertebral disc degeneration (IDD) is recognized as the major contributor to low back pain, which results in disability worldwide and heavy burdens on society and economy. Here we present evidence that the lower level of Nrf2 is closely associated with higher grade of IDD. The apoptosis and senescence of nucleus pulposus cells (NPCs) were exacerbated by Nrf2 knockdown, but suppressed by Nrf2 overexpression under oxidative stress. Based on findings that Kinsenoside could exert multiple pharmacological effects, we found that Kinsenoside rescued the NPC viability under oxidative stress and protected against apoptosis, senescence and mitochondrial dysfunction in a Nrf2-dependent way. Further experiments revealed that Kinsenoside activated a signaling pathway of AKT-ERK1/2-Nrf2 in NPCs. Moreover, in vivo study showed that Kinsenoside ameliorated IDD in a puncture-induced model. Together, the present work suggests that Nrf2 is involved in the pathogenesis of IDD and shows the protective effects as well as the underlying mechanism of Kinsenoside on Nrf2 activation in NPCs.

Kinsenoside attenuates osteoarthritis by repolarizing macrophages through inactivating NF-κB/MAPK signaling and protecting chondrocytes

The objective was to investigate the effect of kinsenoside (Kin) treatments on macrophage polarity and evaluate the resulting protection of chondrocytes to attenuate osteoarthritis (OA) progression. RAW264.7 macrophages were polarized to M1/M2 subtypes then administered with different concentrations of Kin. The polarization transitions were evaluated with quantitative real-time polymerase chain reaction (qRT-PCR), confocal observation and flow cytometry analysis. The mechanism of Kin repolarizing M1 macrophages was evaluated by Western blot. Further, macrophage conditioned medium (CM) and IL-1β were administered to chondrocytes. Micro-CT scanning and histological observations were conducted in vivo on anterior cruciate ligament transection (ACLT) mice with or without Kin treatment. We found that Kin repolarized M1 macrophages to the M2 phenotype. Mechanistically, Kin inhibited the phosphorylation of IκBα, which further reduced the downstream phosphorylation of P65 in nuclear factor-κB (NF-κB) signaling. Moreover, Kin inhibited mitogen-activated protein kinases (MAPK) signaling molecules p-JNK, p-ERK and p-P38. Additionally, Kin attenuated macrophage CM and IL-1β-induced chondrocyte damage. In vivo, Kin reduced the infiltration of M1 macrophages, promoted M2 macrophages in the synovium, inhibited subchondral bone destruction and reduced articular cartilage damage induced by ACLT. All the results indicated that Kin is an effective therapeutic candidate for OA treatment.

Targeted delivery of hesperetin to cartilage attenuates osteoarthritis by bimodal imaging with Gd2(CO3)3@PDA nanoparticles via TLR-2/NF-κB/Akt signaling

The progressive degeneration of cartilage marks the advancement of osteoarthritis (OA), which requires specific targeted treatment for effective cartilage repair. However, there is still no efficient cartilage delivery system or novel magnetic resonance (MR) contrast agent (CA). Herein, we report the synthesis of a novel class of MR CA, Gd₂(CO₃)₃-based nanoparticles (NPs), from a simpler and "greener" approach than previous ones. After the coating of polydopamine (PDA) onto the Gd₂(CO₃)₃ core, we further anchored a cartilage-targeting peptide and loaded hesperetin (Hes) into NPs (Hes-Gd₂(CO₃)₃@PDA-PEG-DWpeptide, HGdPDW), showing excellent cartilage affinity and MR suitability. Additionally, the synthesized HGdPDW exerted significant protective effects against IL-1β stimulation, as shown by the decreased apoptosis and inflammation and increased maturation of chondrocytes in vitro. More importantly, RNA-seq analyses showed the significant reduction of TLR-2 in IL-1β-treated chondrocytes, and this reduction was followed by the inactivation of NF-κB/Akt signaling, leading to the protective effect of HGdPDW. By the establishment of anterior cruciate ligament transection (ACLT) OA mice, the bimodal MRI/IVIS imaging demonstrated the effective cartilage-binding ability of HGdPDW in OA knees with low cytotoxicity, which alleviated the gradual degeneration of articular cartilage in vivo by inhibiting TLR-2 in chondrocytes. Taken together, these results suggest that HGdPDW could target cartilage effectively, thereby protecting chondrocytes from apoptosis and inflammation via TLR-2/NF-κB/Akt signaling. We hope this new class of MRI CA could be applied in not only other fields using MRI technology but also the treatment of general cartilage-related diseases; this application will undoubtedly extend the treatment of OA clinically.

Nerve modulation therapy in gouty arthritis: targeting increased sFRP2 expression in dorsal root ganglion regulates macrophage polarization and alleviates endothelial damage

Gouty arthritis (GA) is a form of arthritis caused by uric acid deposition in the joints that result in intense inflammation and pain. Accumulating evidence showed the importance of the sensory neurons signal upon immune cells by releasing neuropeptides and chemokines to regulate associated immune-inflammatory response. In this study, we investigated the significance of sensory neuron neuropeptides and chemokine signals on inflammation-induced macrophages polarization during GA.

Methods: We screened the mRNA expression profile during GA in dorsal root ganglion (DRG) neurons to identify the most likely candidate that mediates the neuro-immune communication. Then, we silenced specific gene expression in the DRG by lentiviral vectors in the monosodium urate (MSU)-induced ankle GA mouse model and evaluated alterations in the inflammatory response. In vitro, primary macrophages were used to investigate the neural impact on M1/M2 subtype polarization, proinflammatory cytokine production and downstream endothelial damage. Mechanism by which macrophage inflammation is induced in the DRG was evaluated by Western blot, immunofluorescence, and immunoprecipitation.

Results: We found that secreted frizzled-related protein 2 (sFRP2) was the most upregulated gene in dorsal root ganglion (DRG) neurons in response to monosodium urate (MSU) deposition. Injection of LV-sFRP2-shRNA into the L4 and L5 DRG significantly suppressed inflammatory cell infiltration and M1 polarization in the synovial membrane, attenuating hyperalgesia and ankle swelling in the GA mouse model. In vitro, DRG neurons-derived sFRP2 promoted M1 polarization and macrophage migration, thereby upregulating the production of proinflammatory cytokines and preventing endothelial apoptosis. Furthermore, DRG-derived sFRP2 activated the nuclear factor (NF)-κB pathway by destabilizing the β-catenin and p65 complex.

Conclusion: We demonstrated the involvement of a sensory neuron-macrophage axis in GA pathology that was regulated by sFRP2 expression in a paracrine manner. Targeting increased sFRP2 expressions in DRG provide novel insights for future GA research in both pain alleviation and treatment of gout inflammation.

Therapeutic effects of polysaccharides from Anoectochilus roxburghii on type II collagen-induced arthritis in rats

Anoectochilus roxburghii, a famous Chinese herbal medicine, has been commonly used for the treatment of liver disease, diabetes, and rheumatoid arthritis. Our study aimed to investigate the anti-rheumatoid arthritis effects of A. roxburghii polysaccharides (ARP), using the rat's model of type II collagen-induced arthritis (CIA). ARP was prepared by alcohol sedimentation and structurally characterized based on combined chemical, chromatographic and spectroscopic methods. High Performance Size Exclusion Chromatography-Multiangle Laser Light Scattering-Refrative Index (HPSEC-MALLS-RI) analysis revealed that ARP includes two peaks, and the weight-average molecular weight (Mw) of the principal one was estimated as 5.90 kDa with a relative content of 98.2%. Pharmacological results exhibited that ARP significantly decreased the arthritis index and ameliorated the inflammatory cell infiltration and the synovial tissue destruction in CIA rats. Additionally, ARP possessed significant NO production inhibitory effects and antioxidant activity. Further anti-inflammatory mechanism investigations indicated that ARP significantly inhibited the activation of nuclear factor κB (NF-κB) pathway by suppressing the phosphorylation of IκB and p65, which subsequently down-regulated the mRNA expressions of IL-1β and IL-6 in LPS-stimulated RAW 264.7 cells. These findings suggested that ARP has great potential in the development of functional foods and dietary supplements for the treatment of rheumatoid arthritis.

Frontline Science: Reprogramming COX-2, 5-LOX, and CYP4A-mediated arachidonic acid metabolism in macrophages by salidroside alleviates gouty arthritis

Cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX), and cytochrome P450 (CYP) 4A-mediated arachidonic acid (AA) metabolism play an essential role in human inflammatory disorders. Blocking COX-2 pathway would shunt AA metabolism to the other pathway, thereby decreasing the efficacy and exacerbating adverse effects. Here we demonstrated that reprogramming COX-2, 5-LOX, and CYP4A-mediated AA metabolism in macrophages by salidroside (Sal) ameliorates monosodium urate (MSU) crystal-induced inflammation. Compared with COX-2 inhibitor celecoxib, Sal (80 mg/kg) presented a superior anti-arthritic profile in MSU crystal-treated rats, accompanied with the decreased expression of COX-2, 5-LOX, and CYP4A and production of prostaglandin E2 (PGE₂ ), leukotriene B4 (LTB₄ ), and 20-hydroxyeicosatetraenoic acid (20-HETE) in the synovial fluid macrophages. Sal decreased representative M1 marker (iNOS and CD86, etc.) expression and M1 cytokine (TNF-α and IL-1β) production, whereas it increased M2 marker (CD206 and Arg-1) expression and M2 cytokine (TGF-β and IL-10) production. The injection of conditioned medium from MSU crystal-treated macrophages into the ankle joint of rats reproduced the gouty inflammation, which was attenuated by Sal. Mechanistically, down-regulation of COX-2, 5-LOX, and CYP4A in the RAW264.7 and NR8383 macrophages by Sal skewed macrophage polarization away from the M1 phenotype, and thereby prevented neutrophil migration and chondrocyte degradation with STAT1 and NF-κB inactivation. Conversely, overexpression of COX-2, 5-LOX, CYP4A or STAT1, or exogenous addition of IL-1β or TNF-α partially abolished these effects. Together, inhibition of COX-2, 5-LOX, and CYP4A in macrophages by Sal ameliorates MSU crystal-induced inflammation through decreasing TNF-α and IL-1β production, and may serve as a novel therapeutic strategy.

Oral Bioavailability of Kinsenoside in Beagle Dogs Measured by LC-MS/MS: Improvement of Ex Vivo Stability of a Lactone-Containing Compound

Kinsenoside (KD), an active compound isolated from Anoectochilus roxburghii, has demonstrated multiple pharmacological activities including hepatoprotection, antihyperliposis, antihyperglycemia, and antiosteoporosis. To the best of our knowledge, there are no available data concerning its preclinical pharmacokinetics and bioavailability in beagle dogs. To support preclinical pharmacokinetic and bioavailability study, a reliable LC-MS/MS method was developed for KD concentration measurements in beagle dog plasma. The chromatographic separation was achieved on a Waters Atlantis^® Hilic Silica column with an optimum mobile phase consisting of 5 mM ammonium acetate in water (pH 3.0 adjusted with acetic acid) and acetonitrile at a flow rate of 0.2 mL/min. Mass spectrometric analyses were carried out by monitoring multiple reaction monitoring transitions at m/z 265.2→102.9 for KD and m/z 174.0→128.0 for l-phenyl-d₅-alanine-2,3,3-d₃ (IS). The stability of KD in beagle dog whole blood and plasma was systematically evaluated. Lowering the temperature played a more critical role in stabilizing KD than decreasing the pH and adding esterase inhibitors, indicating that the major reason for instability of KD was probably due to chemical hydrolysis rather than esterase-mediated degradation. The currently developed method was validated and applied to a pharmacokinetic and bioavailability study of KD in beagle dogs following oral administration at a dose of 3 mg/kg. The absolute oral bioavailability for KD was determined to be 27.6%. Compared with typical glycosides, KD has a better bioavailability and is suitable for developing an oral dosage form.

Forsythiaside inhibits bacterial adhesion on titanium alloy and attenuates Ti-induced activation of nuclear factor-κB signaling-mediated macrophage inflammation

BACKGROUND

Inflammation and biofilm formation by Staphylococcus aureus (S. aureus) are common causes of periprosthetic infection and loosening. Recently, we identified that forsythiaside is bacteriostatic for S. aureus and methicillin-resistant S. aureus (MRSA). The purpose of the present study was to examine the effect of forsythiaside on S. aureus and MRSA adhesion and biofilm formation on the surface of titanium alloy, which is a popular material for orthopedic joint prostheses.

METHODS

Two strains of S. aureus and MRSA were used for in vitro experiments. The spread plate method, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) were used to characterize antimicrobial activity of forsythiaside. Real-time polymerase chain reaction (RT-PCR) and western blotting were used to investigate the inhibitory level of forsythiaside required for titanium-associated inflammation.

RESULTS

Direct colony counting showed that 16 μg/mL forsythiaside significantly inhibited S. aureus and MRSA adhesion on titanium alloy discs in 2 h. CLSM and SEM showed that higher concentrations (> 30 mg/mL) of forsythiaside effectively inhibited the adhesion of S. aureus and MRSA on the surface of the titanium disc in 24 h. Forsythiaside was capable of attenuating Ti-induced activation of nuclear factor-κB signaling, targeting IκB kinase-α (IKKα) kinases of macrophages, and influencing the expression of NF-κB downstream cytokines.

CONCLUSIONS

These observations suggest that forsythiaside is a potential agent for the treatment of Ti implant-associated infection and inflammation.

Lenalidomide regulates osteocytes fate and related osteoclastogenesis via IL-1β/NF-κB/RANKL signaling

Osteolytic diseases are closely associated with osteocyte fate, indicating a more efficient and crucial role of osteocyte-targeting strategy in inhibiting osteoclastogenesis. Here, we investigated the effects of lenalidomide (Lena) on osteocyte fate in order to regulate osteoclastogenesis via effective cascade-controlling response. Our data revealed that lenalidomide treatment notably rescued IL-1β induced loss of osteocyte viability by inhibiting osteocyte apoptosis with decreased osteoclast-related factors, RANKL and Sclerostin, as demonstrated by the restricted osteoclast formation and reduced bone resorption. Additionally, iTRAQ assay revealed that IL-1β induced activation of NF-κB inhibitor α/β were remarkably downregulated by lenalidomide, showing that lenalidomide impaired NF-κB signaling in osteocytes for inhibiting the expression of osteoclast specific genes in osteoclasts, which was further confirmed by KEGG pathway analysis and Western blot. More interestingly, the in vivo analysis of osteocyte apoptosis and osteoclastogenesis in osteoarthritis mice model indicated a role of lenalidomide in the regulation of osteocyte fate and the consequent inhibition of RANKL-induced osteoclastogenesis. Together, these results suggest that lenalidomide regulates osteocyte fate by attenuating IL-1β/NF-κB signaling, thereby inhibiting RANKL expression for the attenuated osteoclastogenesis both in vitro and vivo, indicating a more efficient remedy among future anti-osteoclastogenesis approaches.

Kinsenoside Ameliorates Oxidative Stress-Induced RPE Cell Apoptosis and Inhibits Angiogenesis via Erk/p38/NF-κB/VEGF Signaling

The pathological superoxidative condition that retinal pigment epithelium (RPE) cells experience contributed to the advancement of age-related macular degeneration (AMD), which was accompanied by significant neovascularization. Therefore, the discovery of novel pharmacological candidates to ameliorate oxidative damage (H₂O₂) against RPE cells and inhibit the following angiogenesis simultaneously is urgently needed. Herein, we found that kinsenoside (Kin), an active component derived from Anoectochilus roxburghii, was able to protect RPE cells effectively and attenuate subsequent angiogenesis. In this study, H₂O₂-induced oxidative injury reduced RPE cell viability and increased cell apoptosis, which was significantly rescued by the treatment with Kin. Compared with H₂O₂ alone, Kin decreased the levels of Bax and increased the production of Bcl-2 in RPE cells. H₂O₂-stimulated VEGF up-regulation was inhibited by Kin treatment. Human umbilical vein endothelial cell (HUVEC) neovascularization induced by conditioned medium (CM) from H₂O₂-stimulated RPE cells was attenuated by treatment with Kin, VEGF antagonist, NF-κB, Erk-MAPK, and p38-MAPK inhibitors. Additionally, H₂O₂-activated phosphorylated expression of IκBα, p65, Erk, and p38 in RPE cells was inhibited by treatment with Kin. Taken together, Kin protected RPE from apoptosis against oxidative stress while simultaneously decreasing apoptosis-related neovascularization. This could be ascribed to the inhibition of Erk/p38/NF-κB signaling by Kin that contributed to the resulting decreased VEGF expression in H₂O₂-treated RPE cells.

Engineering 3D approaches to model the dynamic microenvironments of cancer bone metastasis

Cancer metastasis to bone is a three-dimensional (3D), multistep, dynamic process that requires the sequential involvement of three microenvironments, namely, the primary tumour microenvironment, the circulation microenvironment and the bone microenvironment. Engineered 3D approaches allow for a vivid recapitulation of in vivo cancerous microenvironments in vitro, in which the biological behaviours of cancer cells can be assessed under different metastatic conditions. Therefore, modelling bone metastasis microenvironments with 3D cultures is imperative for advancing cancer research and anti-cancer treatment strategies. In this review, multicellular tumour spheroids and bioreactors, tissue engineering constructs and scaffolds, microfluidic systems and 3D bioprinting technology are discussed to explore the progression of the 3D engineering approaches used to model the three microenvironments of bone metastasis. We aim to provide new insights into cancer biology and advance the translation of new therapies for bone metastasis.

Targeting Osteocytes to Attenuate Early Breast Cancer Bone Metastasis by Theranostic Upconversion Nanoparticles with Responsive Plumbagin Release

The early detection and thus treatment of breast cancer bone metastasis remain a big challenge clinically. As the most abundant cells within bone tissue, osteocytes have been found to manipulate the activity of early cancer bone metastasis by its crosstalk with cancer cells and osteoclasts. However, conventional bone-targeting nanomedicine has limited bone-lesion specificity and ignores the vital role of osteocytes during breast cancer bone metastasis. Also, it lacks detailed insight into the therapeutic mechanisms, which hinders the following translational practice. Previously, we have shown that a combination of zoledronic acid (ZA) and plumbagin (PL) synergistically alleviates cancer-induced bone destruction. Herein, we further develop a pH-responsive bone-targeting drug delivery system, i.e., the ZA-anchored bimodal mesoporous slica covered gadolinium(III) upconversion nanoparticles loaded with PL, to detect and treat bone metastasis sensitively and specifically at an early stage. This multifunctional nanosystem can target osteocytes to release PL as controlled by pH, decreasing osteocytic RANKL expression synergistically through the structural simulation of adenosine phosphate, which competitively inhibits the phosphorylation of osteocytic protein kinase-a, cAMP-response element binding protein, extracellular regulated protein kinase, and c-Jun N-terminal kinase. More importantly, by establishing a breast cancer bone metastasis mice model via intracardiac injection, we show that tumoriogenesis and osteoclastogenesis can both be attenuated significantly. We thereby realize the effective theranostics of tiny bone metastasis in breast cancer bone metastasis. Our work highlights the significance of theranostic nanomedicine and osteocyte-targeting therapy in the treatment of early bone metastasis, which could be applied in achieving efficient theranostic effects for other bone diseases.