The saponin D39 blocks dissociation of non-muscular myosin heavy chain IIA from TNF receptor 2, suppressing tissue factor expression and venous thrombosis

Oleanolic acid administration alleviates neuropathic pain after a peripheral nerve injury by regulating microglia polarization-mediated neuroinflammation

Neuropathic pain caused by a peripheral nerve injury constitutes a great challenge in clinical treatments due to the unsatisfactory efficacy of the current strategy. Microglial activation-mediated neuroinflammation is a major characteristic of neuropathic pain. Oleanolic acid is a natural triterpenoid in food and medical plants, and fulfills pleiotropic functions in inflammatory diseases. Nevertheless, its role in neuropathic pain remains poorly elucidated. In the current study, oleanolic acid dose-dependently suppressed LPS-evoked IBA-1 expression (a microglial marker) without cytotoxicity to microglia, suggesting the inhibitory efficacy of oleanolic acid in microglial activation. Moreover, oleanolic acid incubation offset LPS-induced increases in the iNOS transcript and NO releases from microglia, concomitant with the decreases in pro-inflammatory cytokine transcripts and production including IL-6, IL-1β, and TNF-α. Simultaneously, oleanolic acid shifted the microglial polarization from the M1 phenotype to the M2 phenotype upon LPS conditions by suppressing LPS-induced M1 marker CD16, CD86 transcripts, and enhancing the M2 marker Arg-1 mRNA and anti-inflammatory IL-10 levels. In addition, the LPS-induced activation of TLR4-NF-κB signaling was suppressed in the microglia after the oleanolic acid treatment. Restoring this signaling by the TLR4 plasmid transfection overturned the suppressive effects of oleanolic acid on microglial polarization-evoked inflammation. In vivo, oleanolic acid injection alleviated allodynia and hyperalgesia in SNL-induced neuropathic pain mice. Concomitantly, oleanolic acid facilitated microglial polarization to M2, accompanied by inhibition in inflammatory cytokine levels and activation of TLR4-NF-κB signaling. Collectively, these findings confirm that oleanolic acid may ameliorate neuropathic pain by promoting microglial polarization from pro-inflammatory M1 to anti-inflammatory M2 phenotype via the TLR4-NF-κB pathway, thereby indicating its usefulness as therapeutic intervention in neuropathic pain.

Neuropathic pain caused by a peripheral nerve injury constitutes a great challenge in clinical treatments due to the unsatisfactory efficacy of the current strategy.

Urate transport capacity of glucose transporter 9 and urate transporter 1 in cartilage chondrocytes

Chronic gouty arthritis, caused by a persistent increase in, and the deposition of, soluble uric acid (sUA), can induce pathological chondrocyte destruction; however, the effects of urate transport and intracellular sUA on chondrocyte functionality and viability are yet to be fully determined. Thus, the aim of the present study was to investigate the presence and functionality of a urate transport system in chondrocytes. The expression profiles of two primary urate reabsorptive transporters, glucose transporter 9 (GLUT9) and urate transporter 1 (URAT1), in human articular cartilage and chondrocyte cell lines were examined via western blotting, reverse transcription-quantitative PCR, immunohistochemistry and immunofluorescence. Then, chondrocytes were incubated with exogenous sUA at increasing concentrations. Negative control assays were conducted via the specific knockdown of GLUT9 and URAT1 with lentiviral short hairpin (sh)RNAs, and by pretreatment with benzbromarone, a known inhibitor of the two transporters. Intracellular UA concentrations were measured using colorimetric assays. The expression levels of GLUT9 and URAT1 were determined in cartilage tissues and chondrocyte cell lines. Incubation of chondrocytes with sUA led to a concentration-dependent increase in intracellular urate concentrations, which was inhibited by GLUT9 or URAT1 knockdown, or by benzbromarone pretreatment (27.13±2.70, 44.22±2.34 and 58.46±2.32% reduction, respectively). In particular, benzbromarone further decreased the already-reduced intracellular UA concentrations in HC-shGLUT9 and HC-shURAT1 cells by 46.79±2.46 and 39.79±2.22%, respectively. Cells overexpressing GLUT9 and URAT1 were used as the positive cell control, which showed increased intracellular UA concentrations that could be reversed by treatment with benzbromarone. In conclusion, chondrocytes may possess an active UA transport system. GLUT9 and URAT1 functioned synergistically to transport UA into the chondrocyte cytoplasm, which was inhibited by specific gene knockdowns and drug-induced inhibition. These results may be fundamental in the further investigation of the pathological changes to chondrocytes induced by sUA during gouty arthritis, and identified UA transport processes as potential targets for the early control of chronic gouty arthritis.

Liquiritin from Glycyrrhiza uralensis Attenuating Rheumatoid Arthritis via Reducing Inflammation, Suppressing Angiogenesis, and Inhibiting MAPK Signaling Pathway

Among the various treatments, induction of synoviocyte apoptosis by natural products during a rheumatoid arthritis (RA) pathological condition can be considered to have vast potential. However, it is unclear that liquiritin, a kind of natural flavonoid extracted from the roots of Glycyrrhiza uralensis, induced the apoptosis of the synovial membrane and its molecular mechanism. In this study, interleukin-1β (IL-1β)-RA-FLS cells were incubated with different concentrations of liquiritin. An MTT assay, Hoechst 33342 staining, JC-1 staining, and Western blot were used to check the viability, cell apoptosis, mitochondrial membrane potential changes, and the expression of related proteins, respectively. In vivo, a TUNEL assay and HE staining of tissue were used for histopathological evaluation. Our results showed that liquiritin significantly inhibited the proliferation of IL-1β-induced-RA-FLS, promoted nuclear DNA fragmentation, and changed the mitochondrial membrane potential to accelerate cell apoptosis. Liquiritin downregulated the ratio of Bcl-2/Bax and inhibited the VEGF expression and phosphorylation of JNK and P38. Moreover, liquiritin improved the clinical score of rheumatism, inflammatory infiltration, and angiogenesis and induced apoptosis of the synovial tissue in vivo. Hence, liquiritin ameliorates RA by reducing inflammation, blocking MAPK signaling, and restraining angiogenesis.

YiQiFuMai lyophilized injection attenuates particulate matter-induced acute lung injury in mice via TLR4-mTOR-autophagy pathway

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are the serious diseases that are characterized by a severe inflammatory response of lung injuries and damage to the microvascular permeability, frequently resulting in death. YiQiFuMai (YQFM) lyophilized injection powder is a redeveloped preparation based on the well-known traditional Chinese medicine formula Sheng-Mai-San which is widely used in clinical practice in China, mainly for the treatment of microcirculatory disturbance-related diseases. However, there is little information about its role in ALI/ARDS. The aim of this study was to determine the protective effect of YQFM on particulate matter (PM)-induced ALI. The mice were intratracheally instilled with 50 mg/kg body weight of Standard Reference Material1648a (SRM1648a) in the PM-induced group. The mice in the YQFM group were given YQFM (three doses: 0.33, 0.67, and 1.34 g/kg) by tail vein injection 30 min after the intratracheal instillation of PM. The results showed that YQFM markedly reduced lung pathological injury and the lung wet/dry weight ratios induced by PM. Furthermore, we also found that YQFM significantly inhibited the PM-induced myeloperoxidase (MPO) activity in lung tissues, decreased the PM-induced inflammatory cytokines including interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), reduced nitric oxide (NO) and total protein in bronchoalveolar lavage fluids (BALF), and effectively attenuated PM-induced increases lymphocytes in BALF. In addition, YQFM increased mammalian target of rapamycin (mTOR) phosphorylation and dramatically suppressed the PM-stimulated expression of toll-like receptor 4 (TLR4), MyD88, autophagy-related protein LC3Ⅱand Beclin 1 as well as autophagy. In conclusion, these findings indicate that YQFM had a critical anti-inflammatory effect due to its ability to regulate both TLR4-MyD88 and mTOR-autophagy pathways, and might be a possible therapeutic agent for PM-induced ALI.

Apoptosis effects of imperatorin on synoviocytes in rheumatoid arthritis through mitochondrial/caspase-mediated pathways

Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease associated with a potential imbalance between the growth and death of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs). Imperatorin (IPT) is a naturally occurring furanocoumarin found in umbelliferous vegetables, citrus fruits, and some herbs. The effects of IPT on the proliferation and apoptosis of RA-FLSs and its potential underlying mechanisms have remained unclear. RA-FLSs obtained from RA patients were induced by interleukin-1β (IL-1β) and treated with IPT. Cell viability was determined by MTT assay. Apoptotic cell death was analyzed by Annexin V-FITC/PI double staining and Hoechst 33342 staining. The loss in the mitochondrial membrane potential (ΔΨm) was visualized on the basis of JC-1 staining via fluorescence microscopy, and protein expression changes were assessed by western blot, whereas in vivo studies were conducted in male Wistar rats followed by histopathological assessment via TUNEL assay and HE staining of tissues. The results showed that IPT significantly reduced cell viability, accelerated cell apoptosis and decreased matrix metalloproteinases-1/-3 expression in IL-1β-induced RA-FLSs. Furthermore, IPT exposure was found to disrupt the ΔΨm compared to the IL-1β-induced treatment. Moreover, IPT increased the release of mitochondrial cytochrome C, the ratio of Bax/Bcl-2, and the cleavage of caspase-9, caspase-3 and poly (ADP-ribose) polymerase. In vivo studies showed that IPT not only significantly reduced the collagen induced arthritis by reducing synovial hyperplasia, and pannus formation but also enhanced the apoptotic index of ankle joint cells. Conclusively, our findings suggest that IPT inhibits cell proliferation and induces apoptosis in RA-FLSs that may be associated with mitochondrial/caspase-mediated signalling pathways.

Salicin from Alangium chinense Ameliorates Rheumatoid Arthritis by Modulating the Nrf2-HO-1-ROS Pathways

Rheumatoid arthritis (RA) is a chronic inflammatory disorder linked to oxidative stress of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs). The effects and potential mechanism of salicin on inflammation and oxidative stress of RA-FLSs were examined by MTT, ELISA, and Western blot methods. Salicin significantly reduced cell viability (82.03 ± 7.06, P < 0.01), cytokines (47.70 ± 1.48 ng/L for TNF-α, 30.03 ± 3.49 ng/L for IL-6) ( P < 0.01), and matrix metalloproteinases-1/-3 expression ( P < 0.01) in IL-1β-induced RA-FLSs and inhibited ROS generation and p65 phosphorylation ( P < 0.01) as compared with IL-1β-induced treatment. Moreover, salicin promoted Nrf2 nuclear translocation (2.15 ± 0.21) and HO-1 expression (1.12 ± 0.05) and reduced ROS production in IL-1β-induced RA-FLSs ( P < 0.01). Salicin not only reduced the collagen-induced arthritis by reducing the clinical score ( P < 0.01), inflammatory infiltration, and synovial hyperplasia in vivo but also suppressed the oxidative damage indexes (SOD 155.40 ± 6.53 U/mg tissue, MDA 152.80 ± 5.89 nmol/g tissue, GSH 50.98 ± 3.45 nmol/g tissue, and CAT 0.92 ± 0.10 U/g protein) ( P < 0.01) of ankle joint cells. Conclusively, our findings indicate that salicin ameliorates rheumatoid arthritis, which may be associated with oxidative stress and Nrf2-HO-1-ROS pathways in RA-FLSs.

The saponin D39 blocks dissociation of non-muscular myosin heavy chain IIA from TNF receptor 2, suppressing tissue factor expression and venous thrombosis

BACKGROUND AND PURPOSE

Non-muscular myosin heavy chain IIA (NMMHC IIA) plays a key role in tissue factor expression and venous thrombosis. Natural products might inhibit thrombosis through effects on NMMHC IIA. Here, we have shown that a natural saponin, D39, from Liriope muscari exerted anti-thrombotic activity in vivo, by targeting NMMHC IIA.

EXPERIMENTAL APPROACH

Expression and activity of tissue factor in endothelial cells were analysed in vitro by Western blot and simplified chromogenic assays. Interactions between D39 and NMMHC IIA were assessed by serial affinity chromatography and molecular docking analysis. D39-dependent interactions between NMMHC IIA and TNF receptor 2 (TNFR2) were measured by immunofluorescence, co-immunoprecipitation and proximity ligation assays. Anti-thrombotic activity of D39 in vivo was evaluated with a model of inferior vena cava ligation injury in mice.

KEY RESULTS

D39 inhibited tissue factor expression and procoagulant activities in HUVECs and decreased thrombus weight in inferior vena cava-ligated mice dose-dependently. Serial affinity chromatography and molecular docking analysis suggested that D39 bound to NMMHC IIA. In HEK293T cells, D39 inhibited tissue factor expression evoked by NMMHC IIA overexpression. This effect was blocked by NMMHC IIA knockdown in HUVECs. D39 inhibited dissociation of NMMHC IIA from TNFR2, which subsequently modulated the Akt/GSK3β-NF-κB signalling pathways.

CONCLUSIONS AND IMPLICATIONS

D39 inhibited tissue factor expression and thrombus formation by modulating the Akt/GSK3β and NF-κB signalling pathways through NMMHC IIA. We identified a new natural product that targeted NMMHC IIA, as a potential treatment for thrombotic disorders and other vasculopathies.