Loganin ameliorates cartilage degeneration and osteoarthritis development in an osteoarthritis mouse model through inhibition of NF-κB activity and pyroptosis in chondrocytes

Dehydrocorydaline Accelerates Cell Proliferation and Extracellular Matrix Synthesis of TNFα-Treated Human Chondrocytes by Targeting Cox2 through JAK1-STAT3 Signaling Pathway

Osteoarthritis (OA) causes severe degeneration of the meniscus and cartilage layer in the knee and endangers joint integrity and function. In this study, we utilized tumor necrosis factor α (TNFα) to establish in vitro OA models and analyzed the effects of dehydrocorydaline (DHC) on cell proliferation and extracellular matrix (ECM) synthesis in human chondrocytes with TNFα treatment. We found that TNFα treatment significantly reduced cell proliferation and mRNA and protein expression levels of aggrecan and type II collagen, but caused an increase in mRNA and protein expression levels of type I collagen, matrix metalloproteinase 1/13 (MMP1/13), and prostaglandin-endoperoxide synthase 2 (PTGS2, also known as Cox2) in human chondrocytes. DHC significantly promoted the cell activity of normal human chondrocytes without showing cytotoxity. Moreover, 10 and 20 μM DHC clearly restored cell proliferation, inhibited mRNA and protein expression levels of type I collagen, MMP 1/13, and Cox2, and further increased those of aggrecan and type II collagen in the TNFα-treated human chondrocytes. RNA transcriptome sequencing indicated that DHC could improve TNFα-induced metabolic abnormalities and inflammation reactions and inhibit the expression of TNFα-induced inflammatory factors. Furthermore, we found that the JAK1-STAT3 signaling pathway was confirmed to be involved in the regulatory effects of DHC on cell proliferation and ECM metabolism of the TNFα-treated human chondrocytes. Lastly, to explore the effects of DHC in vivo, we established an anterior cruciate ligament transection (ACLT)-stimulated rat OA model and found that DHC administration significantly attenuated OA development, inhibited the enzymatic hydrolysis of ECM, and reduced phosphorylated JAK1 and STAT3 protein expression in vivo after ACLT for 6 weeks. These results suggest that DHC can effectively relieve OA progression, and it has a potential to be utilized for the clinical prevention and therapy of OA as a natural small molecular drug.

The preventive effect of loganin on oxidative stress-induced cellular damage in human keratinocyte HaCaT cells

Loganin is a type of iridoid glycosides isolated from Corni fructus and is known to have various pharmacological properties, but studies on its antioxidant activity are still lacking. Therefore, in this study, the preventive effect of loganin on oxidative stress-mediated cellular damage in human keratinocyte HaCaT cells was investigated. Our results show that loganin pretreatment in a non-toxic concentration range significantly improved cell survival in hydrogen peroxide (H₂O₂)-treated HaCaT cells, which was associated with inhibition of cell cycle arrest at the G2/M phase and induction of apoptosis. H₂O₂-induced DNA damage and reactive oxygen species (ROS) generation were also greatly reduced in the presence of loganin. Moreover, H₂O₂ treatment enhanced the cytoplasmic release of cytochrome c, upregulation of the Bax/Bcl-2 ratio and degradation of cleavage of poly (ADP-ribose) polymerase, whereas loganin remarkably suppressed these changes. In addition, loganin obviously attenuated H₂O₂-induced autophagy while inhibiting the increased accumulation of autophagosome proteins, including as microtubule-associated protein 1 light chain 3-II and Beclin-1, and p62, an autophagy substrate protein, in H₂O₂-treated cells. In conclusion, our current results suggests that loganin could protect HaCaT keratinocytes from H₂O₂-induced cellular injury by inhibiting mitochondrial dysfunction, autophagy and apoptosis. This finding indicates the applicability of loganin in the prevention and treatment of skin diseases caused by oxidative damage.

Phytochemistry, synthesis, analytical methods, pharmacological activity, and pharmacokinetics of loganin: A comprehensive review

Iridoid glycosides (IGs) are found in many medicinal and edible plants, such as Gardenia jasminoides, Cistanche tubulosa, Eucommia ulmoides, Rehmanniae Radix, Lonicera japonica, and Cornus officinalis. Loganin, an IG, is one of the main active ingredient of Cornus officinalis Sieb. et Zucc., which approved as a medicinal and edible plant in China. Loganin has been widely concerned due to its extensive pharmacological effects, including anti-diabetic, antiinflammatory, neuroprotective, and anti-tumor activities, etc. Studies have shown that these underlying mechanisms include anti-oxidation, antiinflammation and anti-apoptosis by regulating a variety of signaling pathways, such as STAT3/NF-κB, JAK/STAT3, TLR4/NF-κB, PI3K/Akt, MCP-1/CCR2, and RAGE/Nox4/p65 NF-κB signaling pathways. In order to better understand the research status of loganin and promote its application in human health, this paper systematically summarized the phytochemistry, analysis methods, synthesis, pharmacological properties and related mechanisms, and pharmacokinetics based on the research in the past decades.

Network Pharmacology-Based Prediction and Verification of the Potential Targets of Pinoresinol Diglucoside for OA Treatment

Objective

This study aimed to explore the effects and related mechanisms of pinoresinol diglucoside (PDG) on osteoarthritis (OA) via a combination of pharmacology and animal experiments.

Methods

Traditional Chinese Medicine Database and Analysis Platform (TCMSP) Drugbank, Online Mendelian Inheritance in Man, and GeneCards databases were used to predict the putative targets of PGD against OA. A protein protein interaction (PPI) network was constructed in STING database to analyze the interaction network of these targets. Enrichment analysis was performed with DAVID database. The OA model was built by anterior cruciate ligament transection and then injected with PDG for 5 weeks. Hematoxylin and eosin (HE) staining and safranin-fixed green staining were used to evaluate the pathological change. ELISA was applied to measure the serum levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Immunohistochemistry was employed to detect the protein levels of kinase B (AKT), BAX, Bcl2, matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinases 1 (TIMP-1), and phosphatidylinositol 3 kinase (PI3K) in knee cartilage tissues.

Results

Seventy-one key targets were identified, including AKT1, epidermal growth factor receptor, SRC, estrogen receptor 1 (ESR1), and MMP9. Enrichment analysis revealed a series of pathway related to cancer, PI3K-Akt signaling pathway, and proteoglycans in cancer. Animal experiments showed that PDG alleviated the abnormal histomorphological changes of OA; suppressed TIPM, serum IL-1β, IL-6, and TNF-α levels, and PI3K and AKT activation; and increased MMP-1 expression and Bcl2/Bax ratio.

Conclusion

PDG has a cartilage-protecting effect associated with PI3K/AKT signaling pathway in rabbit with OA and therefore might serve as a potential agent for the treatment of this disease.

Anti-arthritic and anti-inflammatory effects of Baccharis conferta Kunth in a kaolin/carrageenan-induced monoarthritis model

ETHNOPHARMACOLOGICAL RELEVANCE

Popularly known as "escoba" (broom) or "escobilla china" (Chinese brush), Baccharis conferta Kunth (Asteraceae), is a plant widely used in Mexican folk medicine for alleviating muscular and rheumatic pain. A recent study described that dichloromethane extract as well as fractions and isolated compounds, possess anti-inflammatory activity in TPA-induced acute edema.

AIM OF THE STUDY

Based on the popular medicinal uses of B. conferta as well as previous studies on its anti-inflammatory activity, the aim of this research was to evaluate the anti-arthritic and anti-inflammatory effects of dichloromethane extract, fractions, and compounds from B. conferta in a monoarthritis model induced with kaolin/carrageenan (K/C).

MATERIALS AND METHODS

Aerial parts of B. conferta were collected, dried, and macerated with dichloromethane. The dichloromethane extract (BcD) was separated by open column chromatography to obtain the BcD2 fraction where the diterpene kingidiol (KIN) was isolated and from the BcD3 fraction the flavonoid cirsimaritin (CIR), which are the most active compounds in the TPA model. In addition, the flavonoids acacetin, pectolinaringenin and 6-methoxykaempferide were identified and isolated from the BcD2 fraction. The content of the main compounds was estimated in BcD, BcD2 and BcD3. The anti-arthritic and anti-inflammatory effects of B. conferta were investigated by evaluating ankle joint inflammation, hyperalgesia using the hot plate test, and pro- and anti-inflammatory cytokine levels in the synovial capsule as well as histological changes in ankle joint tissue in a monoarthritis model induced with K/C in Balb/c mice.

RESULTS

Oral administration of BcD2 fraction (25 mg/kg) and KIN (10 mg/kg) reduced the ankle thickness induced by K/C and decreased the levels of TNF-α, IL-1β, IL-6 and IL-17, while BcD2 increased IL-10. In addition, BcD2 and KIN showed significant edema attenuation of the synovial membrane and decreased inflammatory infiltration and cartilage erosion compared to the VEH group. Finally, BcD (50 mg/kg), KIN (10 mg/kg) and CIR (5 mg/kg) decreased hyperalgesia.

CONCLUSIONS

B. conferta constitutes a therapeutic or preventive candidate for osteoarthritis, because of decreased articular inflammation and pain accompanied with the modulation of cytokine concentrations, which confirms the anti-arthritic and anti-inflammatory activities of B. conferta and support its popular use.

Cell pyroptosis in health and inflammatory diseases

Inflammation is a defense mechanism that can protect the host against microbe invasion. A proper inflammatory response can maintain homeostasis, but continuous inflammation can cause many chronic inflammatory diseases. To properly treat inflammatory disorders, the molecular mechanisms underlying the development of inflammation need to be fully elucidated. Pyroptosis is an inflammation-related cell death program, that is different from other types of cell death. Pyroptosis plays crucial roles in host defense against infections through the release of proinflammatory cytokines and cell lysis. Accumulating evidence indicates that pyroptosis is associated with inflammatory diseases, such as arthritis, pneumonia, and colonitis. Furthermore, pyroptosis is also closely involved in cancers that develop as a result of inflammation, such as liver cancer, esophageal cancer, pancreatic cancer, and colon cancer. Here, we review the function and mechanism of pyroptosis in inflammatory disease development and provide a comprehensive description of the potential role of pyroptosis in inflammatory diseases.

Chloride Channel and Inflammation-Mediated Pathogenesis of Osteoarthritis

Articular cartilage allows the human body to buffer and absorb stress during normal exercise. It is mainly composed of cartilage cells and the extracellular matrix and is surrounded by the extracellular microenvironment formed by synovial fluid and various factors in it. Studies have shown that chondrocytes are the metabolic center of articular cartilage. Under physiological conditions, the extracellular matrix is in a dynamic balance of anabolism and catabolism, and various factors and physical and chemical conditions in the extracellular microenvironment are also in a steady state. This homeostasis depends on the normal function of proteins represented by various ion channels on chondrocytes. In mammalian chondrocyte species, ion channels are mainly divided into two categories: cation channels and anion channels. Anion channels such as chloride channels have become hot research topics in recent years. These channels play an extremely important role in various physiological processes. Recently, a growing body of evidence has shown that many pathological processes, abnormal concentration of mechanical stress and chloride channel dysfunction in articular cartilage lead to microenvironment disorders, matrix and bone metabolism imbalances, which cause partial aseptic inflammation. These pathological processes initiate extracellular matrix degradation, abnormal chondrocyte death, hyperplasia of inflammatory synovium and bony. Osteoarthritis (OA) is a common clinical disease in orthopedics. Its typical manifestations are joint inflammation and pain caused by articular cartilage degeneration, but its pathogenesis has not been fully elucidated. Focusing on the physiological functions and pathological changes of chloride channels and pathophysiology of aseptic inflammation furthers the understanding of OA pathogenesis and provides possible targets for subsequent medication development.

Targeting Cell Death: Pyroptosis, Ferroptosis, Apoptosis and Necroptosis in Osteoarthritis

New research has shown that the development of osteoarthritis (OA) is regulated by different mechanisms of cell death and types of cytokines. Therefore, elucidating the mechanism of action among various cytokines, cell death processes and OA is important towards better understanding the pathogenesis and progression of the disease. This paper reviews the pathogenesis of OA in relation to different types of cytokine-triggered cell death. We describe the cell morphological features and molecular mechanisms of pyroptosis, apoptosis, necroptosis, and ferroptosis, and summarize the current research findings defining the molecular mechanisms of action between different cell death types and OA.

Phytochemicals Mediate Autophagy Against Osteoarthritis by Maintaining Cartilage Homeostasis

Osteoarthritis (OA) is a common degenerative joint disease and is a leading cause of disability and reduced quality of life worldwide. There are currently no clinical treatments that can stop or slow down OA. Drugs have pain-relieving effects, but they do not slow down the course of OA and their long-term use can lead to serious side effects. Therefore, safe and clinically appropriate long-term treatments for OA are urgently needed. Autophagy is an intracellular protective mechanism, and targeting autophagy-related pathways has been found to prevent and treat various diseases. Attenuation of the autophagic pathway has now been found to disrupt cartilage homeostasis and plays an important role in the development of OA. Therefore, modulation of autophagic signaling pathways mediating cartilage homeostasis has been considered as a potential therapeutic option for OA. Phytochemicals are active ingredients from plants that have recently been found to reduce inflammatory factor levels in cartilage as well as attenuate chondrocyte apoptosis by modulating autophagy-related signaling pathways, which are not only widely available but also have the potential to alleviate the symptoms of OA. We reviewed preclinical studies and clinical studies of phytochemicals mediating autophagy to regulate cartilage homeostasis for the treatment of OA. The results suggest that phytochemicals derived from plant extracts can target relevant autophagic pathways as complementary and alternative agents for the treatment of OA if subjected to rigorous clinical trials and pharmacological tests.

LIM mineralization protein-1 inhibits IL-1β-induced human chondrocytes injury by altering the NF-κB and MAPK/JNK pathways

Osteoarthritis (OA) is a common degenerative disease that is associated with the degradation of articular cartilage. Accumulating evidence has confirmed that LIM mineralization protein-1 (LMP-1) is an important agent of bone formation and has been shown to be osteoinductive in various types of disease. However, the underlying mechanisms of LMP-1 in the pathogenesis of OA remain unknown. The present study aimed to evaluate the role and potential mechanism of LMP-1 in IL-1β-stimulated OA chondrocytes. CHON-001 cells were transfected with pcDNA3.1-LMP-1, pcDNA3.1, negative control-small interfering (si)RNA or LMP-1 siRNA for 24 h and then induced by IL-1β for 12 h to establish an OA model in vitro. Cell viability, apoptosis and inflammatory cytokine (IL-6, IL-8 and TNF-α) release were assessed using MTT assay, flow cytometry and ELISA, respectively. The expression levels of LMP-1, cleaved-caspase 3, phosphorylated (p)-p65, p65, p-JNK and JNK were analyzed using reverse transcription-quantitative PCR and western blotting. Overexpression of LMP-1 notably alleviated the IL-1β-induced inflammatory response in CHON-001 cells, as shown by increased cell viability, decreased apoptosis, suppressed expression of cleaved-caspase 3 and a decreased cleaved-caspase 3/caspase 3 ratio. Moreover, IL-1β-induced secretion of IL-6, IL-8 and TNF-α in CHON-001 cells; this was reversed by pcDNA3.1-LMP-1. However, knocking down LMP-1 expression exert opposite effects on the IL-1β-induced inflammatory response in CHON-001 cells, as evidenced by the decreased cell viability, increased apoptosis, enhanced expression of cleaved-caspase 3 and cleaved-caspase 3/caspase 3 ratio and enhanced secretion of IL-6, IL-8 and TNF-α observed. The present data demonstrated that LMP-1 siRNA notably inhibited LMP-1 expression, suppressed cell viability, promoted apoptosis and enhanced cleaved-caspase 3 expression and cleaved-caspase 3/caspase 3 ratio. In addition, LMP-1 siRNA promoted the release of inflammatory factors in CHON-001 cells. It was also found that pcDNA3.1-LMP-1 inhibited p-p65 and p-JNK expression, as well as decreasing the p-p65/p65 and p-JNK/JNK ratio. Nevertheless, there was no significant difference in the mRNA expression levels of p65 and JNK between the groups. Taken together, these findings indicated that overexpression of LMP-1 alleviated IL-1β-induced chondrocytes injury by regulating the NF-κB and MAPK/JNK pathways, suggesting that LMP-1 may be a valuable therapeutic agent for OA treatment.

1,25-Dihydroxyvitamin D Inhibits Osteoarthritis by Modulating Interaction Between Vitamin D Receptor and NLRP3 in Macrophages

Background

Osteoarthritis (OA) is the most prevalent chronic joint disease globally. Loss of extracellular matrix (ECM) by chondrocytes is a classic feature of OA. Inflammatory cytokines, such as interleukin-1β (IL-1β) and interleukin-18 (IL-18), secreted mainly by macrophages, promote expression of matrix degrading proteins and further aggravate progression of OA. 1,25-dihydroxyvitamin D (1,25VD) modulates inflammation thus exerting protective effects on cartilage tissue. However, the underlying mechanisms of 1,25VD activity have not been fully elucidated.

Methods

The destabilization of the medial meniscus (DMM)-induced mice model of OA was established to investigate the protective effects of 1,25VD by micro-CT and Safranin-O and Fast Green staining. And the co-culture system between THP-1 cells and primary chondrocytes was constructed to explore the effects of vitamin D receptor (VDR) and 1,25VD on chondrogenic proliferation, apoptosis, and migration. The immunofluorescence staining and Western blot analysis were used to detect the expressions of ECM proteins and matrix degradation-associated proteases. Enzyme-linked immunosorbent assay (ELISA) was used to examine the expression levels of inflammatory cytokines.

Results

The findings of the study showed that 1,25VD prevented cartilage degeneration and osteophyte formation by inhibiting secretion of inflammatory cytokines in OA mice model. These protective effects were exerted through the vitamin D receptor (VDR). Further studies showed that 1,25VD increased ubiquitination level of NLRP3 by binding to VDR, resulting in decrease in IL-1β and IL-18 secretion. These findings indicate that 1,25VD binds to VDR thus preventing chondrogenic ECM degradation by modulating macrophage NLRP3 activation and secretion of inflammatory cytokines, thus alleviating OA progression.

Conclusion

Here, our study suggests that 1,25VD, targeting to VDR, prevents chondrogenic ECM degradation through regulating macrophage NLRP3 activation and inflammatory cytokines secretion, thereby alleviating OA. These findings provide information on a novel molecular mechanism for application of 1,25VD as OA therapy.

Identifying the mechanism underlying antidepressant-like effects of loganin by network pharmacology in combination with experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Loganin, an iridoid glycoside, is one of the quality control indexes of Cornus officinalis Sieb. et Zucc. Increasing evidence emphasize the important role of inflammation in the pathology of depression, which links depression with other chronic diseases. Loganin prevents inflammatory response in multiple diseases and reverses depressive-like behaviors. However, the mechanisms underlying antidepressant-like effects of loganin for the treatment of inflammation-associated depression are not utterly understood.

AIM OF THE STUDY

The present study was designed to predict the potential targets of loganin against inflammation-associated depression using a network pharmacology approach.

MATERIALS AND METHODS

Pharmmapper and Uniport were used to predict loganin-related targets. Targets of inflammation were identified through GeneCards databases and Online Mendelian Inheritance in Man (OMIM). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were used to identify the potential mechanism. Finally, qRT-PCR and ELISA were used to confirm the role of loganin on these targets.

RESULTS

There were 15 nodes in the loganin-inflammation-depression intersection targets network. In the network, the degree value of CTNNB1 was above 3. Among top ten pathways identified by KEGG analysis, Th1/Th2 cell differentiation and IL-17 signaling pathways were related with both inflammation and depression. As indicated by qRT-PCR results, loganin increased CTNNB1 mRNA level. Moreover, loganin elevated M2 markers of microglia but decreased M1 markers of microglia against lipopolysaccharide (LPS), indicated by qRT-PCR results and ELISA results.

CONCLUSION

CTNNB1 was the main target of loganin. Loganin alleviated LPS-induced inflammation through inhibiting M1 polarization of microglia. Our results provide a better understanding of loganin-induced antidepressant-like effects for the treatment of inflammation-associated depression.

BMSC-Derived Exosomes Ameliorate Osteoarthritis by Inhibiting Pyroptosis of Cartilage via Delivering miR-326 Targeting HDAC3 and STAT1//NF-κB p65 to Chondrocytes

Background

In the past decade, mesenchymal stem cells (MSCs) have been widely used for the treatment of osteoarthritis (OA), and noncoding RNAs in exosomes may play a major role.

Aim

The present study is aimed at exploring the effect and mechanism of miR-326 in exosomes secreted by bone marrow mesenchymal stem cells (BMSCs) on pyroptosis of cartilage and OA improvement.

Methods

Exosomes from BMSCs (BMSC-Exos) were isolated and identified to incubate with OA chondrocytes. Proliferation, migration, specific gene and miR-326 expression, and pyroptosis of chondrocytes were detected. BMSCs or chondrocytes were transfected with miR-326 mimics or inhibitors to investigate the effect of miR-326 in BMSC-Exos on pyroptosis of chondrocytes and the potential mechanism. Finally, a rat OA model was established to verify the effect and mechanism of miR-326 in BMSC-Exos on cartilage of pyroptosis.

Results

Incubation with BMSC-Exos could significantly improve the survival rate, migration ability, and chondrocyte-specific genes (COL2A1, SOX9, Agg, and Prg4) and miR-326 expression of OA chondrocytes and significantly inhibit pyroptosis of chondrocytes by downregulation of the levels of inflammatory cytokines, Caspase-1 activity, and pyroptosis-related proteins such as GSDMD, NLRP3, ASC, IL-1β, and IL-18 (P < 0.01). PKH26 labeling confirmed the uptake of BMSC-Exos by chondrocytes. Incubation with exosomes extracted from BMSCs overexpressing miR-326 can significantly repress the pyroptosis of chondrocytes, while knockdown of miR-326 had the opposite effect (P < 0.01). The same result was also demonstrated by direct interference with the expression level of miR-326 in chondrocytes (P < 0.01). In addition, we found that the overexpression of miR-326 significantly inhibited the expression of HDAC3 and NF-κB p65 and significantly promoted the expression of STAT1, acetylated STAT1, and acetylated NF-κB p65 in chondrocytes (P < 0.01). The targeted relationship between miR-326 and HDAC3 was verified by dual-luciferase reporter assay. Animal experiments confirmed the mechanism by which miR-326 delivered by BMSC-Exos inhibits pyroptosis of cartilage by targeting HDAC3 and STAT1/NF-κB p65 signaling pathway.

Conclusion

BMSC-Exos can deliver miR-326 to chondrocytes and cartilage and improve OA by targeting HDAC3 and STAT1//NF-κB p65 to inhibit pyroptosis of chondrocytes and cartilage. Our findings provide a new mechanism for BMSC-Exos to treat OA.

High fibular osteotomy ameliorates medial compartment knee osteoarthritis in a rabbit model

Knee osteoarthritis (KOA) is a common and severe disease characterized by articular cartilage degeneration, subchondral bone remodeling and inflammation. The purpose of this study was to investigate the therapeutic effects of high fibular osteotomy (HFO) in a KOA rabbit model and to examine the molecular mechanisms involved in medial compartment KOA protective effects. Our data showed that HFO delayed the progression of articular cartilage damage and suppressed subchondral bone remodeling in destabilization of the medial meniscus (DMM)-induced KOA model. HFO also decreased MMP-1, MMP-3, MMP-13 and ADAMTS-5 expression, and increased Col2 and aggrecan expression. In parallel, HFO attenuated the expression of IL-1β, IL-6 and TNF-α. Furthermore, HFO suppressed DMM-mediated NFκB activation, which suggested that the molecular mechanism underlying the protective effect of HFO in medial compartment KOA may be related to the NFκB signaling pathway. Collectively, our data indicated that HFO may be a therapeutic approach to treating medial compartment KOA.

Loganin exerts a protective effect on ischemia-reperfusion-induced acute kidney injury by regulating JAK2/STAT3 and Nrf2/HO-1 signaling pathways

To investigate the role of loganin in hypoxia/reperfusion (H/R)-induced renal tubular epithelial cells and ischemia/reperfusion-induced acute kidney injury (AKI). Cells were received H/R treatment and cultured with different concentrations of loganin. The cell activity and apoptosis were detected. The expressions of apoptosis-related proteins, inflammatory factors, oxidative stress related molecules, and related molecules of JAK2/STAT3 and Nrf2/HO-1 signaling pathways were measured. AKI model of mice was established by I/R procedure, and the kidney was collected for hematoxylin and eosin (HE) staining. H/R treatment inhibited cell activity and apoptosis, but loganin attenuated the effect of H/R. Moreover, loganin inhibited H/R-induced inflammatory response and oxidative stress in tubular epithelial cells. Loganin down-regulated the expression of apoptosis-related proteins, suppressed JAK2/STAT3 pathway, and activated Nrf2/HO-1 pathway. In animal experiment, loganin reduced tubular injury in AKI mice.Loganin had anti-apoptotic, anti-inflammatory, and anti-oxidative stress effects on H/R-induced tubular epithelial cells, and could improve AKI in mice induced by I/R. This effect might be achieved by inhibiting JAK2/STAT3 and activating the Nrf2/HO-1 signaling pathway.

Platelet-rich plasma inhibits Adriamycin-induced inflammation via blocking the NF-κB pathway in articular chondrocytes

Background

Previous studies showed that doxorubicin could lead to osteoarthritis (OA) by inducing chondrocyte inflammation and apoptosis. Besides, it is reported that platelet-rich plasma (PRP) could suppress the activation of inflammatory NF-κB signaling. Here, we aimed to determine whether PRP was able to exert a protective effect against doxorubicin-induced chondrocyte damages.

Methods

To determine whether PRP protects chondrocytes against destabilization of the medial meniscus (DMM)-induced osteoarthritis, mice were treated with PRP and doxorubicin, and the cartilage destruction was observed through Safranin O-fast green staining and osteoarthritis scoring. ELISA assay was used to check the release of TNF-α and ILs. In vitro, we treated chondrocytes with doxorubicin and PRP; CCK-8 was used to measure cell viability. Western blot, real-time PCR, and ELISA were applied to check apoptosis-related signaling and inflammation-associated factors.

Results

The results from the mouse model suggested that PRP attenuated doxorubicin-induced cartilage destruction in vivo. Doxorubicin promoted chondrocyte apoptosis while PRP ameliorated this damage. PRP inhibited doxorubicin-induced dysregulation of cell matrix-related factors, including SOX9, Col2A1, Col10A1, and Aggrecan, reduced protein levels of doxorubicin-induced inflammatory markers, COX-2, and iNOS, and blocked doxorubicin-induced phosphorylation of IκB and NF-κB in articular chondrocytes.

Conclusions

PRP improved doxorubicin-induced damage on chondrocytes. This research might provide a new theoretical basis for the clinical treatment of osteoarthritis caused by doxorubicin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-021-00314-2.

Loganin Inhibits Angiotensin II-Induced Cardiac Hypertrophy Through the JAK2/STAT3 and NF-κB Signaling Pathways

Loganin is an iridoid glycoside extracted from Cornus officinalis, which is a traditional oriental medicine, and many biological properties of loganin have been reported. Nevertheless, it is not clear whether loganin has therapeutic effect on cardiovascular diseases. Hence, the aim of the present study was to investigate the effect of loganin on Ang II-induced cardiac hypertrophy. In the present study, we reported for the first time that loganin inhibits Ang II-provoked cardiac hypertrophy and cardiac damages in H9C2 cells and in mice. Furthermore, loganin can achieve cardioprotective effects through attenuating cardiac fibrosis, decreasing pro-inflammatory cytokine secretion, and suppressing the phosphorylation of critical proteins such as JAK2, STAT3, p65, and IκBα. Besides, the outstanding findings of the present study were to prove that loganin has no significant toxicity or side effects on normal cells and organs. Based on these results, we conclude that loganin mitigates Ang II-induced cardiac hypertrophy at least partially through inhibiting the JAK2/STAT3 and NF-κB signaling pathways. Accordingly, the natural product, loganin, might be a novel effective agent for the treatment of cardiac hypertrophy and heart failure.

The effectiveness of traditional Chinese medicine fumigation and washing nursing care after arthroscopic debridement of Knee Osteoarthritis: A protocol for systematic review and meta-analysis

BACKGROUND

Knee Osteoarthritis (KOA) is a degenerative osteoarthrosis with knee joint pain as the main symptom. In recent years, arthroscopic removal of loose body and repair of meniscus have become common methods for the treatment of KOA. However, postoperative pain, swelling and limited joint movement affect the functional recovery of knee joint and the effect of surgical treatment. Early postoperative control of pain and swelling is of great significance to improve the curative effect of arthroscopic debridement and promote the recovery of knee joint function. In recent years, many clinical studies have reported that the nursing method of fumigation and washing with Chinese medicine after arthroscopic debridement of KOA can relieve pain, promote the recovery of joint function and improve the clinical curative effect, but there is a lack of evidence-based medicine. The purpose of this study is to evaluate the efficacy and safety of fumigation and washing with traditional Chinese medicine after KOA arthroscopy.

METHODS

Computer retrieval English database (PubMed, Embase, Web of Science, the Cochrane Library) and Chinese database (China National Knowledge Infrastructure, Wanfang, VIP Database for Chinese Technical Periodicals, China Biology Medicine disc), moreover manual retrieval academic, Google and baidu from building to since December 2020, traditional Chinese medicine fumigation applied to KOA arthroscopy postoperative nursing of randomized controlled clinical research, by two researchers independently evaluated the quality of the included study and extracted the data. Meta-analysis of the included literatures was performed using RevMan5.3 software.

RESULTS

The main observation index of this study was the effective rate, and the secondary indexes included Visual Analogue Scale Score, the Western Ontario and McMaster university orthopedic index, Lysholms score and adverse reactions, so as to evaluate the efficacy and safety of traditional Chinese medicine fumigation nursing after KOA arthroscopy.

CONCLUSION

This study will provide reliable evidence for the clinical application of Fumigation and washing nursing of traditional Chinese medicine after KOA arthroscopy.

ETHICS AND DISSEMINATION

Private information from individuals will not be published. This systematic review also does not involve endangering participant rights. Ethical approval will not be required. The results may be published in a peer-reviewed journal or disseminated at relevant conferences.

OSF REGISTRATION NUMBER

DOI 10.17605/OSF.IO/THZP4.

Loganin alleviates sepsis-induced acute lung injury by regulating macrophage polarization and inhibiting NLRP3 inflammasome activation

Sepsis is a systemic inflammatory response syndrome resulted from severe infection. Excessive inflammation response plays an important role in sepsis-induced acute lung injury (ALI). Loganin is an iridoid glycoside isolated from Corni fructus and exerts an anti-inflammatory effect in multiple inflammatory diseases; however, the role of loganin in sepsis-induced ALI remains unknown. In the current study, the cecal ligation and puncture (CLP)-induced murine sepsis model was constructed to investigate the anti-inflammatory property of loganin in sepsis-induced ALI. Lipopolysaccharide (LPS)-treated Raw 264.7 cells and primary murine peritoneal macrophages were established to further explore underlying mechanism of loganin. Results showed that intragastrical administration of loganin significantly increased murine survival, reduced the alveolar structure damage and inflammatory cell infiltration. Loganin suppressed the release of the M1 macrophage-associated pro-inflammatory cytokines and induced the activation of M2-type anti-inflammatory cytokines. Besides, loganin dramatically inhibited NLRP3 inflammasome-mediated caspase-1 activation and subsequent IL-1β secretion. Further in vitro studies confirmed that loganin efficiently inhibited M1 macrophage polarization and NLRP3 inflammasome activation by blocking the extra-cellular signal-regulated kinase (ERK) and nuclear factor-kappa B (NF-κB) pathways. Taken together, the anti-inflammatory effect of loganin in sepsis-induced ALI was associated with the ERK and NF-κB pathway-mediated macrophage polarization and NLRP3 inflammasome activation. Our study offers a favorable mechanistic basis to support the therapeutic potential of loganin in anti-inflammatory diseases, such as sepsis-induced ALI.

Safflower Seed Extract Attenuates the Development of Osteoarthritis by Blocking NF-κB Signaling

Although safflower seed extract exhibits pharmacological activity against various diseases, the effects of its individual compounds on osteoarthritis (OA) have not been elucidated. Here, we evaluated the effects of these extracts and their single compounds on OA. N-(p-Coumaroyl) serotonin and N-feruloyl serotonin, main components of safflower seed extract, were isolated by high-performance liquid chromatography. Under in vitro OA mimic conditions, the expression of the matrix metalloproteinases (MMPs) MMP3/13 and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) ADAMTS5 were reduced in mouse chondrocytes treated with safflower seed extract. Furthermore, the oral administration of safflower seed extract attenuated cartilage destruction in a mouse OA model induced by destabilization of the medial meniscus. N-(p-Coumaroyl) serotonin and N-feruloyl serotonin, but not serotonin, reduced MMP3, MMP13, and ADAMTS5 expression in IL-1β-treated chondrocytes. Additionally, they significantly blocked the nuclear factor-κB (NF-κB) pathway by inhibiting IκB degradation and p65 phosphorylation. Our results suggest that safflower seed extract and its single compounds can attenuate cartilage destruction by suppressing MMP and ADMATS5 expression. The anti-arthritic effects are mediated by NF-κB signaling and involve the inhibition of IκB degradation and p65 phosphorylation. These results indicate that safflower seed extract may serve as a novel therapeutic agent against OA.

Morroniside attenuates apoptosis and pyroptosis of chondrocytes and ameliorates osteoarthritic development by inhibiting NF-κB signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Corni Fructus (CF), the red fruit of Cornus officinalis Siebold & Zucc, has been used both as food and medicinal herb in traditional Chinese medicine (TCM). Our previous studies showed that Yougui pills and Bushenhuoxue formula, both TCM prescriptions containing Corni Fructus (CF), have protective effects on osteoarthritis (OA). However, the underlying detailed components in both TCM prescriptions that play therapeutic roles have not been fully defined. Morroniside is a major iridoid glycoside and one of the quality control metrics of CF, but the effects of morroniside on OA remain largely elusive.

AIM OF THE STUDY

The study aims to assess the therapeutic effects of morroniside on cartilage degeneration using a mouse model of OA.

MATERIAL AND METHODS

8-week-old male C57BL/6J mice were randomly divided into 4 groups: Sham, destabilization of the medial meniscus (DMM)-treated with vehicle, DMM-treated with low dose morroniside and DMM-treated with high dose morroniside. Histological staining, immunostaining, and TUNEL staining were conducted to detect changes in tissue morphology, expression of key molecules in chondrocytes, and chondrocyte apoptosis, respectively. Osteophyte formation, meniscus calcification, and subchondral sclerosis were quantitated using micro-CT. The expression of chondrocyte markers was also analyzed by Western blot in primary chondrocytes derived from mice treated with morroniside.

RESULTS

Morroniside attenuated the progression of OA in mice, resulting in substantially reduced osteophyte formation and subchondral sclerosis and lower OARSI scores. Specifically, morroniside significantly promoted cartilage matrix synthesis by increasing collagen type II expression and suppressing chondrocyte pyroptosis. Morroniside administration led to inhibition of matrix metalloproteinase-13 (MMP13), Caspase-1 and nod-like receptor protein-3 (NLRP3) expression in DMM mice and IL-1β-stimulated chondrocytes. In addition, morroniside attenuated the progression of OA by enhancing chondrocyte proliferation and inhibiting chondrocyte apoptosis. Morroniside also attenuated the progression of OA by inhibiting nuclear factor-κB (NF-κB) signaling.

CONCLUSION

Morroniside was protective against cartilage matrix degradation and reduced DMM-induced chondrocyte pyroptosis and apoptosis by the inhibition of NF-κB signaling.

Anti-rheumatoid arthritis effects of iridoid glucosides from Lamiophlomis rotata (Benth.) kudo on adjuvant-induced arthritis in rats by OPG/RANKL/NF-κB signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Lamiophlomisrotata (Benth.) Kudo. has been used to treat trauma bleeding, rheumatism, yellow water disease in traditional Chinese medicine.

AIM

The aim of this work was to evaluate the anti-rheumatoid arthritis (RA) activities and underlying mechanisms of the total iridoid glucosides (TIG) from Lamiophlomisrotata (Benth.) Kudo.

METHODS

The chemical constituents of TIG was analyzed by high-performance liquid chromatography (HPLC) with seven reference compounds (penstemonoside, chlorotuberside, shanzhiside methyl ester, phloyoside, 7-epliamalbide, phlorigidoside C and lamalbide). The anti-rheumatoid arthritis effects of TIG were investigated by arthritis indexes and paw swelling degrees, as well as histopathological and Micro-CT analysis in adjuvant-induced arthritis (AIA) rats. The impacts of TIG on the level of inflammatory cytokines (IL-1β, TNF-α, IL-6, IFN-γ, IL-17 and IL-10), and the regulation of OPG/RANKL/NF-κB pathways were determined by the ELISA and western blot, respectively.

RESULTS

TIG significantly reduced the arthritis indexes and paws swelling in AIA rats, attenuated the inflammation and bone destruction in joint tissues, reduced the generation of pro-inflammatory cytokines IL-1β, TNF-α, IL-6, IFN-γ and IL-17, as well as increased the generation of anti-inflammatory cytokine IL-10 in serum. Moreover, TIG markedly inhibited the expression of p-IKK-α, p-IκB and p-p65, and decreased the ratio of OPG/RANKL in the synovial tissues.

CONCLUSION

TIG possessed significant anti-RA activities on adjuvant-induced arthritis, which might be ascribed to the regulation of inflammatory cytokines IL-1β, TNF-α, IL-6, IFN-γ IL-17 and IL-10, as well as inhibition of OPG/RANKL/NF-κB signaling pathways.

Ameliorative Effects of Loganin on Arthritis in Chondrocytes and Destabilization of the Medial Meniscus-Induced Animal Model

Arthritis is a common inflammatory disease that causes pain, stiffness, and joint swelling. Here, we investigated the ameliorative effects of loganin on arthritis in vitro and in vivo. A single bioactive compound was fractionated and isolated from Cornus officinalis (CO) extract to screen for anti-arthritic effects. A single component, loganin, was identified as a candidate. The CO extract and loganin inhibited the expression of factors associated with cartilage degradation, such as cyclooxygenase-2 (COX-2), matrix metalloproteinase 3 (MMP-3), and matrix metalloproteinase 13 (MMP-13), in interukin-1 beta (IL-1β)-induced chondrocyte inflammation. In addition, prostaglandin and collagenase levels were reduced following treatment of IL-1β-induced chondrocytes with loganin. In the destabilization of the medial meniscus (DMM)-induced mouse model, loganin administration attenuated cartilage degeneration by inhibiting COX-2, MMP-3, and MMP-13. Transverse micro-CT images revealed that loganin reduced DMM-induced osteophyte formation. These results indicate that loganin has protective effects in DMM-induced mice.

The Herba Patriniae (Caprifoliaceae): A review on traditional uses, phytochemistry, pharmacology and quality control

ETHNOPHARMACOLOGICAL RELEVANCE

Herba Patriniae has been used for thousands of years in China as a traditional Chinese medicine with heat-clearing and detoxicating effects. It is applied widly for the treatment of rheumatoid arthritis, diarrhea, acute hepatitis, pelvic inflammatory disease and ulcerative colitis in clinic. Two species, namely Patrinia scabiosaefolia Fisch. (PS) and Patrinia villosa Juss. (PV) from the Caprifoliaceae family, are considered as Herba Patriniae in the pharmaceutical industry.

AIM OF THE REVIEW

This paper aims to comprehensively outline the traditional uses, botanical description, phytochemistry, pharmacology, toxicology, quality control, pharmacokinetics and patents of Herba Patriniae, and elaborate the same/different characteristics between PS and PV.

MATERIALS AND METHODS

Detailed information of Herba Patriniae was collected from various online databases (Pubmed, Web of Science, Google Schola, China National Knowledge Infrastructure Database, National Intellectual Property Administration, PRC National Medical Products Administration), and those published resources (M.Sc. Thesis and books).

RESULTS

A total of 233 compounds have been identified in Herba Patriniae, including triterpenoid saponins, flavonoids, organic acids, iridoids, and volatiles. A very distinct difference was observed, that PS is rich in triterpenoid saponins and volatiles, while PV contains more flavonoids. Two source species of Herba Patriniae gave similar pharmacological effects on anti-cancer, anti-inflammatory, antioxidant, antimicrobial, sedative and hypnotic effects. But there were no reports were on antipruritic, proangiogenic and anti-diarrheal effects for PS, and no studies on anti-diabetic effects for PV. Generally, Herba Patriniae showed non-toxic in the clinical dose, but mild side effects, such as temporary leukopenia, dizziness and nausea, could be found when large and excessive dosage is used. A variety of compounds have been quantified for the quality control of PS and PV. The variety, growth environment, growth time, and harvest time not only affected the contents but also the pharmacological activities of the bioactive compounds. In the past year, patents for compositions containing PV and PS have been filed, mainly involving human health, hygiene, agriculture, and animal husbandry. Unfortunately, the research on pharmacokinetics is insufficient. Only the prototype components and metabolites were repored after intragastric administration of total flavonoids extract from PV in rats.

CONCLUSION

Herba Patriniae has displayed a significant medicinal value in clinic, but the differences in phytochemistry, pharmacological effects and the content of compounds have been found between two official recorded species. About side effects and pharmacokinetic characteristics, the differences between two species have not been well studied. For a better clinical use of Herba Patriniae, it is urgent to establish systematic pharmacology, quality control, pharmacokinetics, and clinical researches on the same/different characteristics between PS and PV.

P2X7 Receptor Induces Pyroptotic Inflammation and Cartilage Degradation in Osteoarthritis via NF-κB/NLRP3 Crosstalk

Osteoarthritis (OA) is an urgent public health problem; however, the underlying causal mechanisms remain unclear, especially in terms of inflammatory mediators in cartilage degradation and chondrocyte imbalance. P2X7 receptor (P2X7R) is a critical inflammation switch, but few studies have examined its function and mechanisms in OA-like pyroptotic inflammation of chondrocytes. In this study, Sprague–Dawley rats were injected in the knee with monosodium iodoacetate (MIA) to induce OA, followed by multiple intra-articular injections with P2X7R antagonist A740003, P2X7R agonist BzATP, NF-κB inhibitor Bay 11-7082, and NLRP3 inhibitor CY-09. Primary rat chondrocytes were harvested and treated similarly. We assessed cell viability, damage, and death via cell viability assay, lactate dehydrogenase (LDH) release, and flow cytometry. Concentrations of adenosine triphosphate (ATP) and interleukin- (IL-) 1β in cell culture supernatant and joint cavity lavage fluid were analyzed by enzyme-linked immunosorbent assay. Changes in expression levels of P2X7 and inflammation-related indicators were analyzed by immunofluorescence, quantitative reverse-transcription polymerase chain reaction, and western blotting. Cell morphology changes and pyroptosis were observed using transmission electron microscopy. Histology, immunohistochemistry, and microcomputed tomography were used to analyze damage to bone and cartilage tissues and assess the severity of OA. Similar to MIA, BzATP reduced cell viability and collagen II expression in a dose-dependent manner. Conversely, A740003 ameliorated MIA-induced cartilage degradation and OA-like pyroptotic inflammation by rescuing P2X7, MMP13, NF-κB p65, NLRP3, caspase-1 (TUNEL-positive and active), and IL-1β upregulation. Additionally, A740003 reduced the caspase-1/propidium iodide double-positive rate, LDH concentration, and reactive oxygen species production. These effects also occurred via coincubation with Bay 11-7082 and CY-09. In conclusion, activated P2X7 promoted extracellular matrix degradation and pyroptotic inflammation in OA chondrocytes through NF-κB/NLRP3 crosstalk, thus, aggravating the symptoms of OA. The study findings suggest P2X7 as a potential target for inflammation treatment, providing new avenues for OA research and therapy.

Comparative intra-articular gene transfer of seven adeno-associated virus serotypes reveals that AAV2 mediates the most efficient transduction to mouse arthritic chondrocytes

Osteoarthritis (OA) is the most common arthropathy, characterized by progressive degeneration of the articular cartilage. Currently, there are no disease-modifying approaches for OA treatment. Adeno-associated virus (AAV)-mediated gene therapy has recently become a potential treatment for OA due to its exceptional characteristics; however, the tropism and transduction efficiency of different AAV serotypes to articular joints and the safety profile of AAV applications are still unknown. The present study aims to screen an ideal AAV serotype to efficiently transfer genes to arthritic cartilage. AAV vectors of different serotypes expressing eGFP protein were injected into the knee joint cavities of mice, with all joint tissues collected 30 days after AAV injection. The transduction efficiency of AAVs was quantified by assessing the fluorescent intensities of eGFP in the cartilage of knee joints. Structural and morphological changes were analyzed by toluidine blue staining. Changes to ECM metabolism and pyroptosis of chondrocytes were determined by immunohistochemical staining. Fluorescence analysis of eGFP showed that eGFP was expressed in the cartilage of knee joints injected with each AAV vector. Quantification of eGFP intensity indicated that AAV2, 7 and 8 had the highest transduction efficiencies. Both toluidine blue staining and Mankin score showed that AAV6 aggravated cartilage degeneration. The analysis of key molecules in ECM metabolism suggested that AAV5 and 7 significantly reduced collagen type II, while AAV9 increased ADAMTS-4 but decreased MMP-19. In addition, transduction with AAV2, 5, 7 and 8 had no obvious effect on pyroptosis of chondrocytes. Comprehensive score analysis also showed that AAV2 had the highest score in intra-articular gene transfer. Collectively, our findings point to AAV2 as the best AAV serotype candidate for gene transfer on arthritic cartilage, resulting in minimal impact to ECM metabolism and pyroptosis of chondrocytes.

Exploration of the mechanism of Zisheng Shenqi decoction against gout arthritis using network pharmacology

BACKGROUND

In this study, the network pharmacological methods were used to predict the target of effective components of compounds in Zisheng Shenqi Decoction (ZSD, or Nourishing Kidney Qi Decoction) in the treatment of gouty arthritis (GA).

METHOD

The main effective components and corresponding key targets of herbs in the ZSD were discerned through the Traditional Chinese Medicine Systems Pharmacology Database and Analysis (TCMSP), Bioinformatics Analysis Tool for Molecular mechanism of Traditional Chinese Medicine (BATMAN-TCM) database. UniProt database and Swiss Target Prediction (STP) database was used to rectify and unify the target names and supply the target information. The targets related to GA were obtained by using GeneCards database. After we discovered the potential common targets between ZSD and GA, the interaction network diagram of "ZSD-component-GA-target" was constructed by Cytoscape software (Version 3.7.1). Subsequently, the Protein-protein interaction (PPI) network of ZSD effective components-targets and GA-related targets was constructed by Search Tool for the Retrieval of Interacting Genes Database (STRING). Bioconductor package "org.Hs.eg.db" and "cluster profiler" package were installed in R software (Version 3.6.0) which used for Gene Ontology analysis and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis.

RESULTS

146 components and 613 targets of 11 herbal medicines in the ZSD were got from TCMSP database and BATMAN-TCM database. 987 targets of GA were obtained from GeneCards database. After intersected and removed duplications, 132 common targets between ZSD and GA were screened out by Cytoscape software (Version 3.7.1). These common targets derived from 81 effective components of 146 components, such as quercetin, stigmasterol and kaempferol. They were closely related to anti-inflammatory, analgesic and anti oxidative stress and the principal targets comprised of Purinergic receptor P2X, ligand-gated ion channel 7 (P2x7R), Nod-like receptor protein 3 (NLRP3) and IL-1β. GO enrichment analysis and KEGG pathway enrichment analysis by R software (Version 3.6.0) showed that the key target genes had close relationship with oxidative stress, reactive oxygen species (ROS) metabolic process and leukocyte migration in aspects of biological process, cell components and molecular function. It also indicated that ZSD could decrease inflammatory reaction, alleviate ROS accumulation and attenuate pain by regulating P2 × 7R and NOD like receptor signaling pathway of inflammatory reaction.

CONCLUSION

A total of 81 effective components and 132 common target genes between ZSD and GA were screened by network pharmacology. The PPI network, GO enrichment analysis and KEGG pathway enrichment analysis suggested that ZSD can exerte anti-inflammatory and analgesic effects on the treatment of GA by reducing decreasing inflammatory reaction, alleviating ROS accumulation, and attenuating pain. The possible molecular mechanism of it mainly involved multiple components, multiple targets and multiple signaling pathways, which provided a comprehensive understanding for further study. In general, the network pharmacological method applied in this study provides an alternative strategy for the mechanism of ZSD in the treatment of GA.

Activating Nrf2 signalling alleviates osteoarthritis development by inhibiting inflammasome activation

Osteoarthritis (OA), which is characterized by proliferation of subchondral bone and the degeneration of articular cartilage, is the most prevalent human arthritis. Nod-like receptor pyrin domain 3 (NLRP3) inflammasome is a hot spot in recent year and has been reported to be associated with OA synovial inflammation. However, there are few studies on NLRP3 inflammasome in chondrocyte. Licochalcone A (Lico A), a compound extracted from Glycyrrhiza species, has various biological effects such as anti-inflammation, anti-apoptotic, anti-cancer and anti-oxidation. In this study, we investigated the protective effect of Lico A on chondrocytes stimulated by lipopolysaccharide (LPS) and surgically induced OA models. In vitro, Lico A could reduce the expression of NLRP3, apoptosis-associated speck-like protein (ASC), Gasdermin D (GSDMD), caspase-1, interleukin-1beta (IL-1β) and IL-18, which indicated that Lico A attenuates LPS-induced chondrocytes pyroptosis. In addition, Lico A ameliorates the degradation of extracellular matrix (ECM) by enhancing the expression of aggrecan and collagen-II. Meanwhile, we found that Lico A inhibits NLRP3 inflammasome via nuclear factor erythroid-2-related factor 2 (Nrf2)/haeme oxygenase-1(HO-1)/nuclear factor kappa-B (NF-κB) axis. And the Nrf2 small interfering RNA (siRNA) could reverse the anti-pyroptosis effects of Lico A in mouse OA chondrocytes. In vivo, Lico A mitigates progression OA in a mouse model and reduces OA Research Society International (OARSI) scores. Thus, Lico A may have therapeutic potential in OA.

miRNA-141 Induced Pyroptosis in Intervertebral Disk Degeneration by Targeting ROS Generation and Activating TXNIP/NLRP3 Signaling in Nucleus Pulpous Cells

The role and mechanism of pyroptosis in intervertebral disk (IVD) degeneration are unclear. MicroRNAs (miRNAs) regulate the viability and function of nucleus pulposus cells (NPCs) in IVDs and are related to pyroptosis. We performed microarray analyses of normal and degenerated nucleus pulposus (NP) to assess the role of pyroptosis and identify key miRNAs in IVD degeneration. We also evaluated the underlying mechanism of miRNA-mediated pyroptosis in NPCs. In addition, we demonstrated the preventative effects of miRNAs on IVD degeneration in a rat model. The levels of the pyroptosis-related proteins cleaved caspase-1, N-terminal gasdermin D (GSDMD), interleukin (IL)-1β, and IL-18 in the degenerative NP were significantly higher than those in the normal NP. miRNA-141 was significantly upregulated in the degenerated NP. miR-141 mimic suppressed the matrix synthesis function of NPCs. By contrast, reactive oxygen species (ROS) generation, and the expression of TXNIP and NLRP3 were significantly downregulated by an miR-141 inhibitor. Furthermore, the miRNA-141 inhibitor prevented the degeneration of IVDs in vivo. Our findings suggest that miRNA-141 induces pyroptosis and extracellular matrix (ECM) catabolism in NPCs by increasing ROS generation and activating TXNIP/NLRP3 signaling. miRNA-141-regulated pyroptosis may be a novel therapeutic target for IVD degeneration.

Mangiferin Relieves Lipopolysaccharide-Induced Injury by Up-Regulating miR-181a via Targeting PTEN in ATDC5 Cells

Background

Mangiferin (MF) was reported to possess anti-inflammatory activity. This investigation tried to probe into the underlying mechanism of MF in osteoarthritis.

Methods

ATDC5 cells were pretreated with series concentrations of MF (0.1, 1, 5, 10, 15, 20 μM) for 2 h and then were exposed to lipopolysaccharide (LPS) (5 μg/ml) for 12 h to construct the inflammatory injury model. The cell viability, productions of pro-inflammatory cytokines and enzymes were respectively measured by employing CCK-8 assay, western blot, ELISA, and quantitative reverse-transcription (qRT)-PCR. miR-181a expression was altered by employing cell transfection. Dichloro-dihydro-fluorescein diacetate (DCFH-DA) method was employed for detection of reactive oxygen species (ROS) generation. Dual luciferase activity assay was conducted for analyzing the relationship between miR-181a and PTEN. The underlying mechanism was determined by employing western blot.

Results

High doses of MF treatment (15 and 20 μM) noticeably induced inflammatory injury exhibiting as increased the productions of pro-inflammatory cytokines, enzymes and ROS, activated NF-κB pathway and deactivated PTEN/PI3K/AKT pathway in ATDC5 cells. Besides, MF treatment notably remitted LPS-induced inflammatory injury through deactivation of NF-κB pathway and activation of PTEN/PI3K/AKT pathway. PTEN was a target of miR-181a. Inhibition of miR-181a remarkably reversed MF-triggered impacts on ATDC5 cells.

Conclusion

MF attenuated LPS-induced inflammatory damage through miR-181a/PTEN axis and thereby inhibiting NF-κB pathway and activating PI3K/AKT pathway.