Inhibition effect of Caragana sinica root extracts on Osteoarthritis through MAPKs, NF-κB signaling pathway

Caragana jubata ethanol extract ameliorates the symptoms of STZ-HFD-induced T2DM mice by PKC/GLUT4 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Caragana jubata (Pall.) Poir., a traditional Tibetan medicinal plant in China, is renowned in Tibetan medicine for its hypoglycemic properties and long-standing use in treating diabetes. Despite its extensive clinical use, the mechanisms underlying its blood sugar-lowering effects still need to be explored. Our investigation contributes a new understanding of the hypoglycemic mechanism of C. jubata, validating its traditional medicinal application by demonstrating its ability to increase GLUT4 expression and glucose uptake, crucial elements in treating type 2 diabetes mellitus (T2DM).

AIM OF THE STUDY

This study investigated the potential anti-diabetic effects of C. jubata ethanol extract (CJEE) by upregulating GLUT4 expression and promoting its integration into the plasma membrane in L6 skeletal muscle cells and diabetic mice. Additionally, the research aimed to uncover the mechanisms involved, particularly focusing on the involvement of the PKC signaling pathway and Ca2⁺ release.

MATERIALS AND METHODS

The chemical composition of CJEE was evaluated using UPLC-Q-TOF/MS. Glucose uptake, GLUT4 expression, and plasma membrane fusion in L6 cells were assessed through a glucose oxidase kit, Western blotting, and laser confocal microscopy, respectively. The modulation of GLUT4 by Akt, AMPK, and PKC signaling pathways was investigated utilizing specific inhibitors. The impact of CJEE on intracellular Ca2⁺ concentration was determined with Fluo-4 dye. Additionally, an in vivo study was conducted on high-fat diet (HFD) and streptozotocin (STZ)-induced type 2 diabetic mice to evaluate the effects of CJEE on blood glucose levels, insulin resistance, lipid metabolism, and pancreatic function.

RESULTS

Chemical analysis of CJEE revealed 18 major constituents, primarily flavonoids. In L6 cells, CJEE was found to significantly enhance glucose uptake, increase GLUT4 expression, and facilitate its fusion with the plasma membrane. The study illustrated that CJEE predominantly activates the PKC pathway, with minimal involvement of the Akt pathway, emphasizing the critical role of Ca2⁺ release in GLUT4 regulation. Diabetic mice treated with CJEE exhibited decreased fasting blood glucose levels, enhanced oral glucose tolerance, reduced insulin resistance, and ameliorated lipid metabolism disorders. Additionally, CJEE elevated GLUT4 expression in insulin-sensitive tissues and alleviated pancreatic and hepatic lesions.

CONCLUSIONS

Our results demonstrated that the activation of the PKC pathway and release of Ca2⁺ by CJEE induce GLUT4 expression, promoting its fusion with the plasma membrane. Consequently, this process boosts glucose uptake and enhances insulin sensitivity, underscoring CJEE as a promising option for managing T2DM.

Caragana sinica (Buc'hoz) Rehd. (jin ji er) polysaccharide regulates the immune function and intestinal microbiota of cyclophosphamide (CTX) induced immunosuppressed mice

ETHNOPHARMACOLOGICAL RELEVANCE

Caragana sinica (Buc'hoz) Rehd. is a plant widely grown in Yunnan, China, for both medicinal and edible purposes. The "National Compilation of Chinese Herbal Medicine" describes its nature as "slightly temperate and sweet". Caragana sinica is usually medicated with whole herbs, the main function is to replenish the kidneys and stop bleeding. Caragana sinica was used in folk medicine in Chuxiong, Yunnan, to treat deficiency colds, fatigue, fever, cough, hypertension, and other diseases.

AIM OF THE STUDY

This article investigates the structural characteristics of Caragana sinica polysaccharide (CSP) and explores its immune-regulatory activity and molecular biological mechanisms in cyclophosphamide-induced immunosuppressed mice, as well as its effects on intestinal bacteria.

METHODS

With the water-extraction and alcohol-precipitation method, Caragana sinica polysaccharide were extracted, obtaining CSP by purification. A variety of methods and techniques have been used to analyze the chemical properties and structural characteristics of CSP. Immunosuppressive mice model was established through intraperitoneal injection of cyclophosphamide (CTX) to study the immune-regulatory effects and mechanisms of CSP.

RESULTS

The data indicated that CSP is a neutral heteropolysaccharide mainly composed of arabinose and galactose. This article uses immunosuppressive mice induced by cyclophosphamide (CTX) as the model. The results showed that CSP can promote the immune function of CTX treated immunosuppressed mice and regulate the diversity and composition of intestinal microbiota. CSP can increase macrophage phagocytosis, NK cell killing activity, and lymphocyte proliferation activity. It can also repair the index and morphological damage of the thymus and spleen. And by binding to the TLR4 receptor, MyD88 was activated and interacted with TRAF6 to promote the transfer of NF-κB into the nucleus. Thereby promoting cytokine release and increasing the production of IL-1β, IL-6, IL-10, TNF-α, IgA, and IgG in the serum. CSP also effectively alleviated the liver damage caused by CTX through antioxidant activity. Furthermore, CSP can dramatically affect the intestinal microbiota and the body's immunity by boosting the relative presence of Bacteroides and Verrucamicrobiota.

CONCLUSIONS

Research results indicated that CSP can regulate the immune function of mice, providing a basis for developing CSP as a potential immune modulator and functional food.

Gremlin-1 promotes IL-1β-stimulated chondrocyte inflammation and extracellular matrix degradation via activation of the MAPK signaling pathway

The role and mechanism of Gremlin-1 in osteoarthritis (OA) were expected to be probed in this study. Firstly, an in vitro OA model was constructed by stimulating human chondrocyte cell line CHON-001 with IL-1β. Next, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) were utilized for assessing the effect of IL-1β with different concentrations (5, 10, and 20 ng/mL) on the activity and Gremlin-1 messenger RNA of CHON-001 cells, respectively. Besides, the influence of knocking down/over-expressing Gremlin-1 on the inflammatory factors (IL-6, TNF-α, IL-18 and PGE2), oxidative stress-related substances (malondialdehyde [MDA]; superoxide dismutase [SOD]; lactate dehydrogenase [LDH]), extracellular matrix (ECM) degradation-related proteins, and mitogen-activated protein kinase (MAPK) pathway proteins in IL-1β-stimulated CHON-001 cells were tested by enzyme-linked immunosorbent assay, related kits, qRT-PCR, and western blot, respectively. IL-1β inhibited CHON-001 cell proliferation and upregulated Gremlin-1 expression in a concentration-dependent manner. Overexpression of Gremlin-1 increased the IL-6, TNF-α, IL-18, PGE2, and MDA levels, enhanced the LDH activity, and decreased the SOD activity in IL-1β-induced CHON-001 cells; while the effect of Gremlin-1 knockdown on the above factors was in contrast with that of the overexpression. Furthermore, overexpression of Gremlin-1 upregulated protein expression of matrix metalloproteinase (MMP)-3, MMP-13, and ADAMTS4 while downregulated protein expression of collagen III, aggrecan, and SOX-9 in IL-1β-stimulated CHON-001 cells. Besides, overexpression of Gremlin-1 increased the p-p38/p38 value while decreased the p-JNK/JNK value in L-1β-stimulated CHON-001 cells; however, knockdown of Gremlin-1 reversed the above results. Gremlin-1 may promote IL-1β-stimulated CHON-001 cell inflammation and ECM degradation by activating the MAPK signaling pathway.

Efficacy of Veronica incana for Treating Osteoarthritis Induced by Monosodium Iodoacetate in Rats

The aim of this study is to investigate the efficacy and the underlying mechanism of Veronica incana in osteoarthritis (OA) induced by intraarticular injection of monosodium iodoacetate (MIA). The selected major four compounds (A-D) of V. incana were found from fractions 3 and 4. Its structure elucidation was determined by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS) data analysis and nuclear magnetic resonance (NMR) data comparison with literature. MIA (50 μL with 80 mg/mL) for the animal experiment was injected into the right knee joint. The V. incana was administered orally every day to rats for 14 days from 7 days after MIA treatment. Finally, we confirmed the four compounds: (A) verproside; (B) catalposide; (C) 6-vanilloylcatapol; and (D) 6-isovanilloylcatapol. When we evaluated the effect of V. incana on the MIA injection-induced knee OA model, there were a noticeable initial decreased in hind paw weight-bearing distribution compared to the Normal group (P < .001), but V. incana supplementation resulted in a significant increase in the weight-bearing distribution to the treated knee (P < .001). Moreover, the V. incana treatment led to a decrease in the levels of liver function enzymes and tissue malondialdehyde (P < .05 and .01). The V. incana significantly suppressed the inflammatory factors through the nuclear factor-kappa B signaling pathway and downregulated the expression of matrix metalloproteinases, which are involved in the degradation of the extracellular matrix (P < .01 and .001). In addition, we confirmed the alleviation of cartilage degeneration through tissue stains. In conclusion, this study confirmed the major four compounds of V. incana and suggested that V. incana could serve as an anti-inflammatory candidate agent for patients with OA.

Core Constituents of Caragana sinica Root for Rheumatoid Arthritis Treatment and the Potential Mechanism

PURPOSE

As a traditional herb product, the root of Caragana sinica (Buc'hoz) Rehder (Chinese name: Jin Quegen [JQG]) has been widely used in folk medicines for rheumatoid arthritis (RA) treatment. However, which herbal constituents exert a core pharmacological role in RA treatment remains a great challenge due to the multiple phytochemical constituents, targets, and pathways. In this work, we aimed to use a new strategy to explore the core herbal constituents and potential mechanisms of JQG against RA for the first time.

METHODS

A successively partitioned extract of JQG, bioactive partition screening in vitro and in vivo, qualitative analysis, bioinformatic analysis, molecular docking, and mechanism validation were used in this study. The partitioned extract was used to obtain the bioactive partition, while in vitro anti-inflammatory effects and in vivo anti-arthritis effects in adjuvant-induced arthritis (AIA) rats were applied to screen the bioactive partition with the best efficacy. Qualitative analysis was used to identify bioactive constituents. Bioinformatic analysis was used to explore the potential mechanism for RA treatment. Molecular docking and immunofluorescence were used to validate the underlying mechanism.

RESULTS

After successively partitioning extract and bioactive partition screening, ethyl acetate extract (EAE) yielded the best anti-inflammatory effects in vitro and in vivo among JQG extracts. By ultra-performance liquid chromatography (UPLC) coupled with Orbitrap mass spectrometry, a total of 58 constituents were identified in EAE, and 17 constituents were regarded as the core constituents based on their oral bioavailability and drug-like properties. The nuclear factor kappa B (NF-κB) signal pathway was screened as the core pathway of core constituents for RA treatment based on bioinformatic analysis, and the core constituents showed good ligand-receptor binding activity to NF-κB P65. In vitro study demonstrated that EAE could significantly reduce NF-κB P65 transfer from the cytoplasm to the nucleus.

CONCLUSION

Our study suggested that the therapeutic efficacy of JQG for RA treatment could be derived from negative regulation of the NF-κB pathway, and EAE of JQG could represent a promising herb product for RA treatment that deserves further development.

Potential Anti-Inflammatory and Chondroprotective Effect of Luzula sylvatica

(1) Interest in the Juncaceae family has risen as some members have shown anti-inflammatory properties and interesting compounds. In this regard, we decided to investigate the antioxidant and anti-inflammatory properties of Luzula sylvatica, a Juncaceae not yet extensively studied, in the context of osteoarthritis. (2) The Luzula sylvatica Ethanol extract (LS-E) was used to test the production of reactive oxygen species (ROS) by leucocytes, the IL1β and PGE2 production by peripheral blood mononuclear cells (PBMCs), the production of EP4, and the activation of NFκB in THP-1, as well as the IL1β-activated normal human knee articular chondrocytes (NHAC-Kn) gene expression, grown in monolayers or maintained in alginate beads. (3) Organic acids, caffeoylquinic acids, quercetin and luteolin, compounds frequently found in this family were identified. The LS-E exhibited inhibited ROS formation. The LS-E did not affect NFκB activation and IL1β secretion but dampened the secretion of PGE2 by PBMCs and the presence of EP4 in THP-1. It also modulated the expression of NHAC-Kn in both models and inhibited the expression of several proteases and inflammatory mediators. (4) Luzula sylvatica might supply interesting antioxidant protection against cartilage damages and lessen joint inflammation, notably by decreasing PGE2 secretion in the synovial fluid. Moreover, it could act directly on chondrocytes by decreasing the expression of proteases and, thus, preventing the degradation of the extracellular matrix.

Potential role of nutraceuticals via targeting a Wnt/β-catenin and NF-κB pathway in treatment of osteoarthritis

Osteoarthritis (OA) is a disease due to the aging of the articular cartilage, a post-mitotic tissue that stays functioning until primary homeostatic processes fail. Because of pain and disability, OA significantly influences national healthcare expenses and patient quality of life. It is a whole-joint illness characterized by inflammatory and oxidative signaling pathways and significant epigenetic alterations that cause cartilage extracellular matrix degradation. The canonical Wnt pathway (Wnt/β-catenin pathway) and nuclear factor kappa B (NF-κB) signaling pathways may function in joint tissues by modulating the activity of synovial cells, osteoblasts, and chondrocytes. However, finding innovative ways to treat osteoarthritis and get the joint back to average balance is still a struggle. Nutraceuticals are dietary supplements that promote joint health by balancing anabolic and catabolic signals. New therapeutic methods for OA treatment have been developed based on many research findings that show nutraceuticals have strong anti-inflammation, antioxidant, anti-bone resorption, and anabolic properties. For the treatment of osteoarthritis, we explore the possible involvement of nutraceuticals that target the Wnt/β-catenin and NF-κB pathways. PRACTICAL APPLICATIONS: In keeping with the aging population, osteoarthritis is becoming more widespread. In this extensive research, we studied the role of the Wnt/β-catenin and NF-κB pathway in OA formation and progression. Nutraceuticals that target these OA-related signaling pathways are a viable therapy option. Wnt/β-catenin and NF-κB signaling pathway are inhibited by polyphenols, flavonoids, alkaloids, and vitamins from the nutraceutical category, making them possible therapeutic drugs for OA therapy.

Plant Nutrition for Human Health: A Pictorial Review on Plant Bioactive Compounds for Sustainable Agriculture

Is there any relationship between plant nutrition and human health? The overall response to this question is very positive, and a strong relationship between the nutrition of plants and humans has been reported in the literature. The nutritional status of edible plants consumed by humans can have a negative or positive impact on human health. This review was designed to assess the importance of plant bioactive compounds for human health under the umbrella of sustainable agriculture. With respect to the first research question, it was found that plant bioactives (e.g., alkaloids, carotenoids, flavonoids, phenolics, and terpenoids) have a crucial role in human health due to their therapeutic benefits, and their potentiality depends on several factors, including botanical, environmental, and clinical attributes. Plant bioactives could be produced using plant tissue culture tools (as a kind of agro-biotechnological method), especially in cases of underexploited or endangered plants. Bioactive production of plants depends on many factors, especially climate change (heat stress, drought, UV radiation, ozone, and elevated CO2), environmental pollution, and problematic soils (degraded, saline/alkaline, waterlogged, etc.). Under the previously mentioned stresses, in reviewing the literature, a positive or negative association was found depending on the kinds of stress or bioactives and their attributes. The observed correlation between plant bioactives and stress (or growth factors) might explain the importance of these bioactives for human health. Their accumulation in stressed plants can increase their tolerance to stress and their therapeutic roles. The results of this study are in keeping with previous observational studies, which confirmed that the human nutrition might start from edible plants and their bioactive contents, which are consumed by humans. This review is the first report that analyzes this previously observed relationship using pictorial presentation.

Chondroprotective Effects of 4,5-Dicaffeoylquinic Acid in Osteoarthritis through NF-κB Signaling Inhibition

Osteoarthritis (OA) is characterized by cartilage degradation, inflammation, and pain. The dicaffeoylquinic acid (diCQA) isomer, 4,5-diCQA, exhibits antioxidant activity and various other health-promoting benefits, but its chondroprotective effects have yet to be elucidated. In this study, we aimed to investigate the chondroprotective effects of 4,5-diCQA on OA both in vitro and in vivo. Primary rat chondrocytes were pre-treated with 4,5-diCQA for 1 h before stimulation with interleukin (IL)-1β (5 ng/mL). The accumulation of nitrite, PGE₂, and aggrecan was observed using the Griess reagent and ELISA. The protein levels of iNOS, COX-2, MMP-3, MMP-13, ADMATS-4, MAPKs, and the NF-κB p65 subunit were measured by Western blotting. In vivo, the effects of 4,5-diCQA were evaluated for 2 weeks in a destabilization of the medial meniscus (DMM)-surgery-induced OA rat model. 4,5-diCQA significantly inhibited IL-1β-induced expression of nitrite, iNOS, PGE₂, COX-2, MMP-3, MMP-13, and ADAMTS-4. 4,5-diCQA also decreased the IL-1β-induced degradation of aggrecan. It also suppressed the IL-1β-induced phosphorylation of MAPKs and translocation of the NF-κB p65 subunit to the nucleus. These findings indicate that 4,5-diCQA inhibits DMM-surgery-induced cartilage destruction and proteoglycan loss in vivo. 4,5-diCQA may be a potential therapeutic agent for the alleviation of OA progression. In this study, diclofenac was set to be administered once every two days, but it showed an effect on OA. These results may be used as basic data to suggest a new dosing method for diclofenac.

MicroRNA-10a-3p Improves Cartilage Degeneration by Regulating CH25H-CYP7B1-RORα Mediated Cholesterol Metabolism in Knee Osteoarthritis Rats

Osteoarthritis (OA) is a worldwide degenerative joint disease that seriously impaired the quality of life of patients. OA has been established as a disease with metabolic disorder. Cholesterol 25-hydroxylase (CH25H) was proved to play a key role in cartilage cholesterol metabolism. However, the biological function and mechanism of CH25H in OA remains further investigation. Growing researches have proved the vital roles of miRNAs in OA progression. In this study, we screened out miR-10a-3p through high-throughput miRNA sequencing which may bind to CH25H. Molecular mechanism investigation indicated that miR-10a-3p is an upstream target of CH25H. Functional exploration revealed miR-10a-3p suppressed the inflammatory responses, cholesterol metabolism and extracellular matrix (ECM) degradation in primary chondrocytes. Moreover, rescue assays implied that miR-10a-3p reversed CH25H plasmids induced inflammatory cytokine production and ECM degradation. Furthermore, the OA rat model was established to explore the function of miR-10a-3p in vivo. The results showed that miR-10a-3p can recover the OA features through targeting CH25H/CYP7B1/RORα axis. In conclusion, these findings implied a crucial role of miR-10a-3p/CH25H/CYP7B1/RORα axis in OA, which may provide a promising therapeutic strategy for OA.

Flower extract of Caragana sinica. ameliorates DSS-induced ulcerative colitis by affecting TLR4/NF-κB and TLR4/MAPK signaling pathway in a mouse model

OBJECTIVES

This study aimed to find out the protective effects and preliminary mechanisms of the flower extract of Caragana sinica (FEC) on dextran sulfate sodium salt (DSS)-induced colitis.

MATERIALS AND METHODS

The ulcerative colitis models of mice induced by 3% DSS were established and treated with FEC. Body weight changes, disease activity index (DAI), colon histopathological score, anti-oxidant ability, and the level of inflammatory cytokines were determined. The expression of Toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88) were assessed in colonic tissue by immunohistochemical staining. Western blot was used to analyze the expression of TLR4/ nuclear factor kappa-B (NF-κB) and TLR4/ mitogen-activated protein kinase (MAPK) signaling pathway-related proteins.

RESULTS

FEC significantly prevented body weight loss and colonic shortening and reduced the disease activity index and histopathological score (P<0.05). Moreover, FEC treatment remarkably down-regulated the levels of myeloperoxidase (MPO), interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6) and up-regulated the levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and interleukin 10 (IL-10) in the colon of DSS mice (P<0.05). Furthermore, the expression of TLR4/NF-κB and TLR4/MAPK pathway-related proteins was inhibited by FEC (P<0.05).

CONCLUSION

Our findings demonstrated that FEC could serve as a potential therapeutic agent for treatment of ulcerative colitis.