Lonicerin alleviates the progression of experimental rheumatoid arthritis by downregulating M1 macrophages through the NF-κB signaling pathway

Lonicerin targets ADRA1D and RSPO3 to ameliorate diabetes-induced vascular injury through Ca2+/Calcineurin/NFAT1-dependent anti-EndMT pathway

BACKGROUND

Cardiovascular complications are the primary cause of mortality and disability among diabetic patients. Lonicerin, a major bioactive compound in Lonicera japonica Thunb., has unclear effects and mechanisms on diabetic vascular injury.

PURPOSE

The research aims to investigate the therapeutic effects of lonicerin on diabetic vascular injury and elucidate its underlying molecular mechanisms.

METHODS

Streptozotocin (STZ)-induced mice and high glucose-treated human aortic endothelial cells (HAECs) were employed as animal and cellular models of diabetes. Endothelial-to-mesenchymal transition (EndMT) was validated by examining EndMT-related markers and endothelial/mesenchymal functions. RNA sequencing was used to identify potential mechanisms through which lonicerin alleviates EndMT. The relationship between lonicerin and its targets was investigated using RNAi, plasmid overexpression, western blot, qRT-PCR, immunofluorescence, flow cytometry, and calcineurin activity assays.

RESULTS

Lonicerin dose-dependently alleviates diabetes-induced vascular injury (intimal damage, inflammation, calcification, and fibrosis) and EndMT. Lonicerin produces anti-EndMT effect by inhibiting cytoplasmic Ca²⁺ levels. Further analysis reveals that adrenoceptor alpha 1D (ADRA1D) and R-spondin 3 (RSPO3) are targets of lonicerin. Lonicerin reduces high glucose-induced upregulation of ADRA1D and RSPO3, leading to decreased cytoplasmic Ca²⁺ levels. This reduction inhibits calcineurin activity, promotes nuclear factor of activated T cells 1 (NFAT1) phosphorylation, and prevents its nuclear translocation, ultimately exerting an anti-EndMT effect. EC-specific overexpression of ADRA1D or RSPO3 negates the inhibitory effects of lonicerin on EndMT and its therapeutic impact on diabetic vascular injury.

CONCLUSION

Lonicerin targets ADRA1D and RSPO3 to ameliorate diabetes-induced vascular injury through the Ca2+/Calcineurin/NFAT1-dependent anti-EndMT pathway. Thus, this study provides the first evidence that lonicerin is a potential novel therapeutic agent for diabetic vasculopathy.

Lonicerin regulates AMPK/SIRT1/autophagy pathway to attenuate heat stress intestinal injury and inhibit inflammation

Intestinal injury is one of the most prevalent complications following heat stress (HS) in both humans and animals. Autophagy has been shown to maintain intestinal homeostasis, and modulation of autophagy may help alleviate intestinal injury caused by HS. Lonicerin (LN) are flavonoids known to have enhanced autophagy and anti-inflammatory effects. However, how LN prevent intestinal damage and regulate autophagy after HS remains unknown. The aim of this study was to elucidate the potential regulatory effects of LN on intestinal inflammation and intestinal barrier function in a HS model, and to elucidate the underlying molecular mechanisms. Firstly, we searched for the same inflammatory cytokines in the drug and disease targets through network pharmacology, and in vitro and in vivo experiments showed that LN significantly inhibited the production of pro-inflammatory cytokines. Then it was demonstrated that LN alleviates HS induced intestinal mucosal barrier damage by repairing tight junctions, goblet cells, and mucins in the colon of rats, consistent with the findings of in vitro experiments. In addition, LN reversed HS-induced reduced autophagic flux and maintained autophagic homeostasis via the AMP-activated protein kinase (AMPK)-Silent information regulator 1 (SIRT1) pathway in intestinal epithelial cells and intestinal system. In summary, this study demonstrated that LN exert intestinal protective and immunomodulatory effects by inhibiting the production of pro-inflammatory cytokines, maintaining the integrity of the intestinal mucosal barrier, and the level of AMPK-SIRT1 autophagy.

Assessment of Sedative Activity of Lonicerin: In Vivo Approach With Pharmacokinetics and Molecular Docking

BACKGROUND

Lonicerin (LON) has been identified to have different biological properties, such as anticancer, anti-inflammatory, immunomodulatory, antibacterial, antimicrobial, and neuroprotective. This study aims to assess the sedative effect of LON in Swiss albino mice, which is yet to be discovered.

MATERIALS AND METHODS

Mice were treated with two different doses of LON (5 and 10 mg/kg) and 2 mg/kg of diazepam (DZP), which is the referral GABAergic medication, and the latency time and sleeping duration of animals were observed. A computational study was also conducted to evaluate the docking scores and display the binding sites of LON and receptor (GABAA α1 and β2 subunits). The study also investigated the pharmacokinetics and drug-likeness properties of LON along with toxicological analysis by using SwissADME and Protox-3 software, respectively.

RESULTS

Findings revealed that the higher concentration of LON reduced the latency (9.86 ± 1.44 min) and increased the sleep duration (191.29 ± 7.43 min) compared to the lower concentration. Besides, the combination group of LON and DZP showed the lowest latency (6.17 ± 0.82 min) and highest sleeping time (219.00 ± 6.39 min). In the in silico study, LON exhibited a strong docking score (-8.1 kcal/mol) with the macromolecules, which is closer to the binding affinity of DZP (-8.3 kcal/mol), indicating that LON could show strong sedative activity by binding with the GABAA receptor. Computational toxicity analysis revealed that LON is non-hepatotoxic, non-neurotoxic, noncarcinogenic, noncytotoxic, non-ecotoxic, and non-mutagenic.

CONCLUSION

Therefore, LON may be effective for the treatment of insomnia in the near future.

Vanillic acid ameliorates collagen-induced arthritis by suppressing the inflammation response via inhibition of the MAPK and NF-κB signaling pathways

OBJECTIVE

To explore the potential therapeutic effects and underlying mechanism of vanillic acid (VA) in the treatment of rheumatoid arthritis (RA).

METHODS

A collagen-induced arthritis (CIA) model was established in DBA/1 J mice. Methotrexate (MTX, 1 mg/kg/d) and VA (5 mg/kg/d, 10 mg/kg/d, 20 mg/kg/d) were then administered to investigate their therapeutic efficacy on RA in vivo. The body weight, joint score, and spleen index of the mice in different experimental groups were evaluated. Micro-CT was performed to detect joint destruction in the mice, and HE staining was utilized to observe the pathological conditions of their joints and spleens. Quantitative real-time PCR (qRT-PCR) and enzyme linked immunosorbent assay (ELISA) were used to detect inflammatory cytokines and chemokines. Changes in synovial tissue signaling pathways were detected using immunohistochemistry. For in vitro analysis, RAW 264.7 cells were pretreated with different concentrations of VA (25, 50, 100 μg/ml) and then treated with lipopolysaccharide (LPS), and changes in their signaling pathways were detected by western blot (WB).

RESULTS

VA improved the clinical symptoms and bone destruction of arthritis in CIA mice, reduced pathological damage to ankle synovial and spleen tissue, and inhibited polarization of macrophages to M1 in the synovial tissue as well. In addition, VA inhibited the expression of TNF-α, IL-6, IL-1β, MCP-1, and iNOS in CIA mice and in LPS-stimulated RAW264.7 cells and also inhibited the phosphorylation of p65, IκBα, ERK, JNK, and p38 MAPKs.

CONCLUSIONS

VA can significantly improve the clinical symptoms of RA and exerts anti-inflammatory effects by inhibiting the activation of the NF-κB/MAPK pathway.

Potential mechanisms of rheumatoid arthritis therapy: Focus on macrophage polarization

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that affects multiple organs and systems in the human body, often leading to disability. Its pathogenesis is complex, and the long-term use of traditional anti-rheumatic drugs frequently results in severe toxic side effects. Therefore, the search for a safer and more effective antirheumatic drug is extremely important for the treatment of RA. As important immune cells in the body, macrophages are polarized. Under pathological conditions, macrophages undergo proliferation and are recruited to diseased tissues upon stimulation. In the local microenvironment, they polarize into different types of macrophages in response to specific factors and perform unique functions and roles. Previous studies have shown that there is a link between macrophage polarization and RA, indicating that certain active ingredients can ameliorate RA symptoms through macrophage polarization. Notably, Traditional Chinese medicine (TCM) monomer component and compounds demonstrate a particular advantage in this process. Building upon this insight, we reviewed and analyzed recent studies to offer valuable and meaningful insights and directions for the development and application of anti-rheumatic drugs.

Sporidiobolus pararoseus polysaccharides relieve rheumatoid arthritis by regulating arachidonic acid metabolism and bone remodeling signaling pathway

Rheumatoid arthritis (RA) is an autoimmune-mediated disease with the highest disability rate. Sporidiobolus pararoseus polysaccharides (SPP) have been demonstrated to have anti-rheumatoid and microbiota-modulatory effects; however, the underlying mechanisms remain unclear. This study employed collagen-induced arthritis (CIA) mice to explore the metabolic and genetic pathways. The results revealed SPP intervention significantly reduced the serum levels of rheumatoid and pro-inflammatory complement factors. SPP promoted the transition of macrophages of CIA mice toward the M2 phenotype (F4/80+/CD206+) from an inflammatory phenotype (F4/80+/CD86+) using flow cytometry analysis. A total of 44 metabolites were upregulated, and 110 metabolites were significantly downregulated by SPP compared to those in RA group. The decreased metabolites, 12(S)-HPETE, prostaglandin H2, 15-HETE, hepoxilin B3, and 15-keto-prostaglandin F2a, were mostly enriched in arachidonic acid metabolism (enrichment = 11.4 %), which was highly correlated with the anti-rheumatic activity of SPP. Gene expression analysis revealed that SPP significantly regulated OPG/RANKL/TRAF6 signaling pathway, stimulating osteogenic remodeling. Furthermore, arachidonic acid metabolism was identified as the critical metabolic driver of RA phenotypes and osteoclast differentiation, potentially associated with SPP-reshaped intestinal microbiota (i.e., Rikenellaceae_RC9_gut_group, Bacteroides, and Parabacteroides). Collectively, this study utilized an integrated approach of metabolomics and gene expression analysis to investigate the regulatory role of SPP in RA progression.

Lonicerin protects pancreatic acinar cells from caerulein-induced apoptosis, inflammation, and ferroptosis by activating the SIRT1/GPX4 signaling pathway

Acute pancreatitis (AP) is a familiar emergency of digestive system characterized by pancreatic inflammation. Lonicerin (LCR) has been reported to exert anti-inflammatory and immunomodulatory characteristics in several inflammatory diseases. Nevertheless, its role and mechanism involved in AP are still unknown. This study was designed to explore the protective effect and potential mechanism of LCR in AP. In this study, LCR and ferrostatin-1 alleviated, but erastin aggravated caerulein (CAE) exposure-induced cytotoxicity and reduction of cell viability in AR42J cells. LCR exhibited a protective role in CAE-treated AR42J cells, as evidenced by alleviation of apoptosis, inflammation, and ferroptosis. Mechanistically, LCR decreased the phosphorylation level of nuclear factor-kappa B p65 and increased the levels of silent information regulator 1 (SIRT1) and glutathione peroxidase 4 (GPX4) in CAE-treated AR42J cells. Furthermore, functional rescue experiments manifested that knockdown of SIRT1 partially negated the inhibitory action of LCR against CAE-induced apoptosis, inflammation, and ferroptosis in AR42J cells. Overall, LCR mitigates apoptosis, inflammation, and ferroptosis in CAE-exposed AR42J cells, which is related to the activation of the SIRT1/GPX4 signaling pathway.

Lonicerin alleviates intestinal myenteric neuron injury induced by hypoxia/reoxygenation treated macrophages by downregulating EZH2

Intestinal ischemia-reperfusion (IR) injury is a common gastrointestinal disease that induces severe intestinal dysfunction. Intestinal myenteric neurons participate in maintaining the intestinal function, which will be severely injured by IR. Macrophages are widely reported to be involved in the pathogenesis of organ IR injury, including intestine, which is activated by NLRP3 signaling. Lonicerin (LCR) is a natural extracted monomer with inhibitory efficacy against the NLRP3 pathway in macrophages. The present study aims to explore the potential protective function of LCR in intestinal IR injury. Myenteric neurons were extracted from mice. RAW 264.7 cells were stimulated by H/R with or without 10 μM and 30 μM LCR. Remarkable increased release of IL-6, MCP-1, and TNF-α were observed in H/R treated RAW 264.7 cells, along with an upregulation of NLRP3, cleaved-caspase-1, IL-1β, and EZH2, which were sharply repressed by LCR. Myenteric neurons were cultured with the supernatant collected from each group. Markedly decreased neuron number and shortened length of neuron axon were observed in the H/R group, which were signally reversed by LCR. RAW 264.7 cells were stimulated by H/R, followed by incubated with 30 μM LCR with or without pcDNA3.1-EZH2. The inhibition of LCR on NLRP3 signaling in H/R treated RAW 264.7 cells was abolished by EZH2 overexpression. Furthermore, the impact of LCR on neuron number and neuron axon length in myenteric neurons in the H/R group was abated by EZH2 overexpression. Collectively, LCR alleviated intestinal myenteric neuron injury induced by H/R treated macrophages via downregulating EZH2.

IGJ depletion suppresses proliferation, inflammation, and motility of rheumatoid arthritis fibroblast-like synoviocytes via targeting NF-κB pathway

OBJECTIVE

To investigate the impact of IGJ on the proliferation, inflammation, and motility of rheumatoid arthritis (RA) fibroblast-like synoviocytes and elucidate the underlying mechanism.

METHODS

The expression of IGJ RA fibroblast-like synoviocytes was assessed using immunoblot and qPCR. Cell growth was evaluated using CCK-8 and FCM assays. The effects on inflammatory response were determined by ELISA and immunoblot assays. Cell motility was assessed using transwell and immunoblot assays. The mechanism was further confirmed using immunoblot assays.

RESULTS

IGJ expression was found to be elevated in fibroid synovial cells of RA. IGJ ablation inhibited the growth of MH7A cells and suppressed the inflammatory response. Knockdown of IGJ also blocked cell motility. Mechanically, the knockdown of IGJ suppressed the NF-κB axis in MH7A cells.

CONCLUSION

IGJ suppresses RA in fibroblast-like synoviocytes via NF-κB pathway.

Autophagy: A potential target for natural products in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease primarily affecting the mucosa of the colon and rectum. UC is characterized by recurrent episodes, often necessitating lifelong medication use, imposing a significant burden on patients. Current conventional and advanced treatments for UC have the disadvantages of insufficient efficiency, susceptibility to drug resistance, and notable adverse effects. Therefore, developing effective and safe drugs has become an urgent need. Autophagy is an intracellular degradation process that plays an important role in intestinal homeostasis. Emerging evidence suggests that aberrant autophagy is involved in the development of UC, and modulating autophagy can effectively alleviate experimental colitis. A growing number of studies have established that autophagy can interplay with endoplasmic reticulum stress, gut microbiota, apoptosis, and the NLRP3 inflammasome, all of which contribute to the pathogenesis of UC. In addition, a variety of intestinal epithelial cells, including absorptive cells, goblet cells, and Paneth cells, as well as other cell types like neutrophils, antigen-presenting cells, and stem cells in the gut, mediate the development of UC through autophagy. To date, many studies have found that natural products hold the potential to exert therapeutic effects on UC by regulating autophagy. This review focuses on the possible effects and pharmacological mechanisms of natural products to alleviate UC with autophagy as a potential target in recent years, aiming to provide a basis for new drug development.

NLRP3 inflammasome and its role in autoimmune diseases: A promising therapeutic target

The NOD-like receptor protein 3 (NLRP3) inflammasome is a protein complex that regulates innate immune responses by activating caspase-1 and the inflammatory cytokines IL-1β and IL-18. Numerous studies have highlighted its crucial role in the pathogenesis and development of inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, autoimmune thyroid diseases, and other autoimmune diseases. Therefore, investigating the underlying mechanisms of NLRP3 in disease and targeted drug therapies holds clinical significance. This review summarizes the structure, assembly, and activation mechanisms of the NLRP3 inflammasome, focusing on its role and involvement in various autoimmune diseases. This review also identifies studies where the involvement of the NLRP3 inflammasome in the disease mechanism within the same disease appears contradictory, as well as differences in NLRP3-related gene polymorphisms among different ethnic groups. Additionally, the latest therapeutic advances in targeting the NLRP3 inflammasome for autoimmune diseases are outlined, and novel clinical perspectives are discussed. Conclusively, this review provides a consolidated source of information on the NLRP3 inflammasome and may guide future research efforts that have the potential to positively impact patient outcomes.

Lonicerin alleviates ovalbumin-induced asthma of mice via inhibiting enhancer of zeste homolog 2/nuclear factor-kappa B signaling pathway

Asthma is the most common chronic disease in the respiratory system of children caused by abnormal immunity that responses to common antigens. Lonicerin exerts anti-inflammatory activity in other inflammatory models through targeting enhancer of zeste homolog 2 (EZH2) that is related to asthma. We sought to explore the role and mechanism of lonicerin in regulating allergic airway inflammation. Mice were intraperitoneally injected 10 µg ovalbumin (OVA) on postnatal day 5 (P5) and P10, and then inhaled 3% aerosolized OVA for 10 min every day on P18-20, to establish asthmatic mice model. Lonicerin (10 or 30 mg/kg) was given to mice by intragastric administration on P16-P20. Notably, the administration of lonicerin amended infiltration of inflammatory cells and mucus hypersecretion. OVA-specific IgE level, inflammatory cell count and inflammatory cytokines in asthmatic mice were reduced after lonicerin treatment. Moreover, it suppressed the activity of EZH2 and activation of nuclear factor-kappa B (NF-κB) as evidenced by decreasing tri-methylation of histone H3 at lysine 27 and reducing nuclear translocation of NF-κB p65. In a word, Lonicerin may attenuate asthma by inhibiting EZH2/NF-κB signaling pathway.

Immunomodulatory effects of curcumin on macrophage polarization in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by synovial inflammation, cartilage destruction, pannus formation and bone erosion. Various immune cells, including macrophages, are involved in RA pathogenesis. The heterogeneity and plasticity of macrophages render them pivotal regulators of both the induction and resolution of the inflammatory response. Predominantly, two different phenotypes of macrophages have been identified: classically activated M1 macrophages exacerbate inflammation via the production of cytokines, chemokines and other inflammatory mediators, while alternatively activated M2 macrophages inhibit inflammation and facilitate tissue repair. An imbalance in the M1/M2 macrophage ratio is critical during the initiation and progression of RA. Macrophage polarization is modulated by various transcription factors, epigenetic elements and metabolic reprogramming. Curcumin, an active component of turmeric, exhibits potent immunomodulatory effects and is administered in the treatment of multiple autoimmune diseases, including RA. The regulation of macrophage polarization and subsequent cytokine production as well as macrophage migration is involved in the mechanisms underlying the therapeutic effect of curcumin on RA. In this review, we summarize the underlying mechanisms by which curcumin modulates macrophage function and polarization in the context of RA to provide evidence for the clinical application of curcumin in RA treatment.

Natural compounds target programmed cell death (PCD) signaling mechanism to treat ulcerative colitis: a review

Ulcerative colitis (UC) is a nonspecific inflammatory bowel disease characterized by abdominal pain, bloody diarrhea, weight loss, and colon shortening. However, UC is difficult to cure due to its high drug resistance rate and easy recurrence. Moreover, long-term inflammation and increased disease severity can lead to the development of colon cancer in some patients. Programmed cell death (PCD) is a gene-regulated cell death process that includes apoptosis, autophagy, necroptosis, ferroptosis, and pyroptosis. PCD plays a crucial role in maintaining body homeostasis and the development of organs and tissues. Abnormal PCD signaling is observed in the pathological process of UC, such as activating the apoptosis signaling pathway to promote the progression of UC. Targeting PCD may be a therapeutic strategy, and natural compounds have shown great potential in modulating key targets of PCD to treat UC. For instance, baicalin can regulate cell apoptosis to alleviate inflammatory infiltration and pathological damage. This review focuses on the specific expression of PCD and its interaction with multiple signaling pathways, such as NF-κB, Nrf2, MAPK, JAK/STAT, PI3K/AKT, NLRP3, GPX4, Bcl-2, etc., to elucidate the role of natural compounds in targeting PCD for the treatment of UC. This review used (ulcerative colitis) (programmed cell death) and (natural products) as keywords to search the related studies in PubMed and the Web of Science, and CNKI database of the past 10 years. This work retrieved 72 studies (65 from the past 5 years and 7 from the past 10 years), which aims to provide new treatment strategies for UC patients and serves as a foundation for the development of new drugs.

Sinensetin Attenuated Macrophagic NLRP3 Inflammasomes Formation via SIRT1-NRF2 Signaling

Macrophage-mediated inflammation plays essential roles in multiple-organ injury. Sinensetin (SNS) at least exhibits anti-inflammation, antioxidant, and antitumor properties. However, the underlying mechanism of SNS-targeted macrophage-mediated inflammation remains elusive. In the present study, our results showed that SNS suppressed lipopolysaccharide (LPS)-induced inflammation to ameliorate lung and liver injuries. Mechanistically, SNS significantly inhibited M1-type macrophage polarization and its NLRP3 inflammasome formation to significantly decrease tumor necrosis factor α (TNFα) and IL-6 expression, while increasing IL-10 expression. Moreover, SNS interacted and activated SIRT1 to promote NRF2 and its target gene SOD2 transcription, which subsequently decreased LPS-induced inflammation. SIRT1 knockdown impaired the effects of SNS on the inhibition of macrophage polarization, NLRP3 inflammasome formation, and NRF2/SOD2 signaling. Taken together, our results showed that SNS is a potential and promising natural active ingredient to ameliorate inflammatory injury via activating SIRT1/NRF2/SOD2 signaling.

Targeting different phenotypes of macrophages: A potential strategy for natural products to treat inflammatory bone and joint diseases

BACKGROUND

Macrophages, a key class of immune cells, have a dual role in inflammatory responses, switching between anti-inflammatory M2 and pro-inflammatory M1 subtypes depending on the specific environment. Greater numbers of M1 macrophages correlate with increased production of inflammatory chemicals, decreased osteogenic potential, and eventually bone and joint disorders. Therefore, reversing M1 macrophages polarization is advantageous for lowering inflammatory factors. To better treat inflammatory bone disorders in the future, it may be helpful to gain insight into the specific mechanisms and natural products that modulate macrophage polarization.

OBJECTIVE

This review examines the impact of programmed cell death and different cells in the bone microenvironment on macrophage polarization, as well as the effects of natural products on the various phenotypes of macrophages, in order to suggest some possibilities for the treatment of inflammatory osteoarthritic disorders.

METHODS

Using 'macrophage polarization,' 'M1 macrophage' 'M2 macrophage' 'osteoporosis,' 'osteonecrosis of femoral head,' 'osteolysis,' 'gouty arthritis,' 'collagen-induced arthritis,' 'freund's adjuvant-induced arthritis,' 'adjuvant arthritis,' and 'rheumatoid arthritis' as search terms, the relevant literature was searched using the PubMed, the Cochrane Library and Web of Science databases.

RESULTS

Targeting macrophages through different signaling pathways has become a key mechanism for the treatment of inflammatory bone and joint diseases, including HIF-1α, NF-κB, AKT/mTOR, JAK1/2-STAT1, NF-κB, JNK, ERK, p-38α/β, p38/MAPK, PI3K/AKT, AMPK, AMPK/Sirt1, STAT TLR4/NF-κB, TLR4/NLRP3, NAMPT pathway, as well as the programmed cell death autophagy, pyroptosis and ERS.

CONCLUSION

As a result of a search of databases, we have summarized the available experimental and clinical evidence supporting herbal products as potential treatment agents for inflammatory osteoarthropathy. In this paper, we outline the various modulatory effects of natural substances targeting macrophages in various diseases, which may provide insight into drug options and directions for future clinical trials. In spite of this, more mechanistic studies on natural substances, as well as pharmacological, toxicological, and clinical studies are required.