Scutellarin inhibits RANKL-mediated osteoclastogenesis and titanium particle-induced osteolysis via suppression of NF-κB and MAPK signaling pathway

Scutellarin alleviates renal ischemia-reperfusion injury by inhibiting the MAPK pathway and pro-inflammatory macrophage polarization

Renal ischemia-reperfusion injury (IRI) is an integral process in renal transplantation, which results in compromised graft survival. Macrophages play an important role in both the early inflammatory period and late fibrotic period in response to IRI. In this study, we investigated whether scutellarin (SCU) could protect against renal IRI by regulating macrophage polarization. Mice were given SCU (5-50 mg/kg) by gavage 1 h earlier, followed by a unilateral renal IRI. Renal function and pathological injury were assessed 24 h after reperfusion. The results showed that administration of 50 mg/kg SCU significantly improved renal function and renal pathology in IRI mice. In addition, SCU alleviated IRI-induced apoptosis. Meanwhile, it reduced macrophage infiltration and inhibited pro-inflammatory macrophage polarization. Moreover, in RAW 264.7 cells and primary bone marrow-derived macrophages (BMDMs) exposed to SCU, we found that 150 μM SCU inhibited these cells to polarize to an inflammatory phenotype induced by lipopolysaccharide (LPS) and interferon-γ (IFN-γ). However, SCU has no influence on anti-inflammatory macrophage polarization in vivo and in vitro induced by in interleukin-4 (IL-4). Finally, we explored the effect of SCU on the activation of the mitogen-activated protein kinase (MAPK) pathway both in vivo and in vitro. We found that SCU suppressed the activation of the MAPK pathway, including the extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK), and p38. Our results demonstrated that SCU protects the kidney against IRI by inhibiting macrophage infiltration and polarization toward pro-inflammatory phenotype via the MAPK pathway, suggesting that SCU may be therapeutically important in treatment of IRI.

Reyanning mixture inhibits M1 macrophage polarization through the glycogen synthesis pathway to improve lipopolysaccharide-induced acute lung injury

ETHNOPHARMACOLOGICAL RELEVANCE

Reyanning (RYN) mixture is a traditional Chinese medicine composed of Taraxacum, Polygonum cuspidatum, Scutellariae Barbatae and Patrinia villosa and is used for the treatment of acute respiratory system diseases with significant clinical efficacy.

AIM OF THE STUDY

Acute lung injury (ALI) is a common clinical disease characterized by acute respiratory failure. This study was conducted to evaluate the therapeutic effects of RYN on ALI and to explore its mechanism of action.

MATERIALS AND METHODS

Ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to analyze the chemical components of RYN. 7.5 mg/kg LPS was administered to induce ALI in rats. RYN was administered by gavage at doses of 2 ml/kg, 4 ml/kg or 8 ml/kg every 8 h for a total of 6 doses. Observations included lung histomorphology, lung wet/dry (W/D) weight ratio, lung permeability index (LPI), HE staining, Wright-Giemsa staining. ELISA was performed to detect the levels of TNF-α, IL-6, IL-10, Arg-1,UDPG. Immunohistochemical staining detected IL-6, F4/80 expression. ROS, MDA, SOD, GSH/GSSG were detected in liver tissues. Multiple omics techniques were used to predict the potential mechanism of action of RYN, which was verified by in vivo closure experiments. Immunofluorescence staining detected the co-expression of CD86 and CD206, CD86 and P2Y14, CD86 and UGP2 in liver tissues. qRT-PCR detected the mRNA levels of UGP2, P2Y14 and STAT1, and immunoblotting detected the protein expression of UGP2, P2Y14, STAT1, p-STAT1.

RESULTS

RYN was detected to contain 1366 metabolites, some of the metabolites with high levels have anti-inflammatory, antibacterial, antiviral and antioxidant properties. RYN (2, 4, and 8 ml/kg) exerted dose-dependent therapeutic effects on the ALI rats, by reducing inflammatory cell infiltration and oxidative stress damage, inhibiting CD86 expression, decreasing TNF-α and IL-6 levels, and increasing IL-10 and Arg-1 levels. Transcriptomics and proteomics showed that glucose metabolism provided the pathway for the anti-ALI properties of RYN and that RYN inhibited lung glycogen production and distribution. Immunofluorescence co-staining showed that RYN inhibited CD86 and UGP2 expressions. In vivo blocking experiments revealed that blocking glycogen synthesis reduced UDPG content, inhibited P2Y14 and CD86 expressions, decreased P2Y14 and STAT1 mRNA and protein expressions, reduced STAT1 protein phosphorylation expression, and had the same therapeutic effect as RYN.

CONCLUSION

RYN inhibits M1 macrophage polarization to alleviate ALI. Blocking glycogen synthesis and inhibiting the UDPG/P2Y14/STAT1 signaling pathway may be its molecular mechanism.

Scutellarin Loaded on Ultradeformable Nanoliposome Scutellarin EDTMP (S-UNL-E) Promotes Osteogenesis in Osteoporotic Rats

Scutellarin is known as a safe, effective, and low-cost traditional Chinese medicine and has a variety of biological activities. Studies reported that the scutellarin loaded on ultradeformable nanoliposome scutellarin EDTMP (S-UNL-E) could promote osteoblast differentiation and bone formation in vitro. However, its effect on promoting osteogenesis in vivo is still unclear. In this study, pharmacology network and transcriptome sequencing were used to screen the potential targets and pathways of scutellarin in treating osteoporosis. The female Sprague-Dawley (SD) rats were operated on with bilateral oophorectomy and femoral defect to establish an osteoporosis model and then treated separately with bone dust, single scutellarin, 40 mg/kg ultradeformable nanoliposome scutellarin (S-UNL), and the optimal concentration of 40 mg/kg S-UNL-E for a total of 56 d to detect the parameters of trabecular bones. And qRT-PCR and western blot were performed to determine the expression of prostaglandin-endoperoxide synthase 2 (PTGS2), alkaline phosphatase (ALP), transcription factor 4 (TCF4), and β-catenin. Results of microscopic computed tomography (Micro-CT) of trabecular bones showed that single scutellarin, S-UNL, and S-UNL-E all promoted the bone formation of osteoporotic rats, in which S-UNL-E manifested the most remarkable therapeutic effect. And it is found that 40 mg/kg of S-UNL-E increased the expression of PTGS2, ALP, TCF4, and β-catenin, which indicated that S-UNL-E stimulated the secretion of ALP in bone defect areas to promote bone healing, and increased PTGS2 expression thereby enhancing the transcription and translation of key gene β-catenin and TCF4 in the Wnt/β-catenin signaling pathway to treat osteoporotic rats.

The potential role of herbal extract Wedelolactone for treating particle-induced osteolysis: an in vivo study

Background

Osteolysis is one of the most prevalent clinical complications affecting people who undergo total joint replacement (TJR). Wedelolactone (WDL) is a coumestan compound derived from the Wedelia chinensis plant and has been demonstrated to exhibit anti-inflammatory properties. This study aimed to investigate the oral administration of WDL as a potential treatment for particle-induced osteolysis using a well-established mice calvarial disease model.

Methods

Thirty-two C57BL/6 J mice were randomized into four groups: Sham, vehicle, osteolysis group with oral WDL treatment for 4 weeks (WDL 4w), and osteolysis group treated for 8 weeks (WDL 8w). Micro-CT was used to quantitatively analyze the bone mineral density (BMD), bone volume/tissue volume (BV/TV) and trabecular bone thickness (Tb.Th). Osteoclast numbers were also measured from histological slides by two investigators who were blind to the treatment used.

Results

The results from micro-CT observation showed that BMD in the WDL 8w group improved significantly over the vehicle group (p < 0.05), but there was no significant difference between WDL 4w and 8w for BV/TV and Tb.Th. Osteoclast numbers in the WDL 4w group were also lower than the vehicle group (p < 0.05), but the difference between WDL 8w and 4w groups was not significant.

Conclusions

Particle-induced osteolysis is an inevitable long-term complication after TJR. The results of this animal study indicate that an oral administration of WDL can help reduce the severity of osteolysis without adverse effects.

Photoluminescent carbon dots (PCDs) from sour apple: a biocompatible nanomaterial for preventing UHMWPE wear-particle induced osteolysis via modulating Chemerin/ChemR23 and SIRT1 signaling pathway and its bioimaging application

Photoluminescent nanomaterials have been widely employed in several biological applications both in vitro and in vivo. For the first time, we report a novel application of sour apple-derived photoluminescent carbon dots (PCDs) for reducing ultra-high molecular weight polyethylene (UHMWPE) wear particle-induced osteolysis using mouse calvarial model. Generally, aseptic prosthetic loosening seems to be a significant postoperative problem for artificial joints replacement, which is mainly contributed by UHMWPE-induced osteolysis. Hence, inhibiting osteoclastic bone-resorption could minimize UHMWPE-induced osteolysis for implant loosening. Prior to osteolysis studies, the prepared sour apple-derived PCDs were employed for bioimaging application. As expected, the prepared PCDs effectively inhibited the UHMWPE particle-induced osteoclastogenesis in vitro. The PCDs treatment effectively inhibited the UHMWPE-induced osteoclast differentiation, F-actin ring pattern, and bone resorption in vitro. Also, the PCDs reduced the UHMWPE-induced ROS stress as well as the expression level of pro-inflammatory cytokines, including TNF-α, IL-1, IL-6, and IL-8. Further, the qPCR and western blot results hypothesized that PCDs inhibited the UHMWPE wear particle-induced osteolysis through suppressing chemerin/ChemR23 signaling and NFATc1 pathway, along with upregulation of SIRT1 expression. Overall, these findings suggest that the synthesized PCDs could be a potential therapeutic material for minimizing UHMWPE particle-induced periprosthetic osteolysis to avoid postoperative complications.

How to Prevent Aseptic Loosening in Cementless Arthroplasty: A Review

Aseptic loosening is the main late postoperative complication of cementless total hip arthroplasties (THAs), leading to pain and functional impairment. This article aims to update the orthopedic surgeon on the various methods by which the aseptic loosening rate can be reduced. We performed a systematic review by searching the PubMed database for hip aseptic loosening. We included meta-analysis, randomized controlled trials, reviews, and systematic reviews in the last 10 years, which provided information on techniques that can prevent aseptic loosening in total hip arthroplasty. From a total of 3205 articles identified, 69 articles (2%) met the inclusion criteria, leading to a total of 36 recommendations. A lot of research has been conducted in terms of septic loosening in the last decade. Currently, we have various techniques by which we can reduce the rate of aseptic loosening. Nevertheless, further randomized clinical trials are needed to expand the recommendations for aseptic loosening prevention.

Indigo Pulverata Levis (Chung-Dae, Persicaria tinctoria) Alleviates Atopic Dermatitis-like Inflammatory Responses In Vivo and In Vitro

Atopic dermatitis (AD) is a chronic inflammatory skin disease associated with a type 2 T helper cell (Th2) immune response. The IndigoPulverata Levis extract (CHD) is used in traditional Southeast Asian medicine; however, its beneficial effects on AD remain uninvestigated. Therefore, we investigated the therapeutic effects of CHD in 2,4-dinitrochlorobenzene (DNCB)-induced BALB/c mice and tumor necrosis factor (TNF)-α- and interferon gamma (IFN)-γ-stimulated HaCaT cells. We evaluated immune cell infiltration, skin thickness, and the serum IgE and TNF-α levels in DNCB-induced AD mice. Moreover, we measured the expression levels of pro-inflammatory cytokines, mitogen-activated protein kinase (MAPK), and the nuclear factor-kappa B (NF-κB) in the mice dorsal skin. We also studied the effect of CHD on the translocation of NF-κB p65 and inflammatory chemokines in HaCaT cells. Our in vivo results revealed that CHD reduced the dermis and epidermis thicknesses and inhibited immune cell infiltration. Furthermore, it suppressed the proinflammatory cytokine expression and MAPK and NF-κB phosphorylations in the skin tissue and decreased serum IgE and TNF-α levels. In vitro results indicated that CHD downregulated inflammatory chemokines and blocked NF-κB p65 translocation. Thus, we deduced that CHD is a potential drug candidate for AD treatment.

Preparation and characterization of scutellarin loaded on ultradeformable nano-liposomes scutellarin EDTMP (S-UNL-E) and in vitro study of its osteogenesis

The present research aimed to elucidate a convenient, safe and economic approach to induce the growth of endogenous bone tissue and bone regeneration. S-UNL-E was prepared using reverse-phase evaporation, and scutellarin encapsulation was subsequently compared. Meanwhile, the optimal preparation scheme was developed using an orthogonal method, and the particle size was determined using laser light scattering. In osteoblasts cultured in vitro, methyl thiazolyl tetrazolium (MTT), alkaline phosphatase (ALP) staining and alizarin red staining were used to detect the osteogenic effects of S-UNL-E. The results indicated that the optimal process conditions for S-UNL-E included mass ratios of phospholipid-cholesterol, phospholipid-breviscapine, phospholipid-sodium cholate, and phospholipid-stearamide were 2:1, 15:1, 7:1 and 7:1, respectively, and the mass of ethylenediamine tetramethylphosphonic acid (EDTMP) was 30 mg. The average particle size of S-UNL-E was 156.67 ± 1.76 nm, and Zeta potential was −28.77 ± 0.66 mv. S-UNL-E substantially increased the expression of ALP osteoblasts, elevated the content of osteocalcin protein and promoted the formation of mineralized nodules. Cells in the S-UNL-E group were densely distributed with integrated cell structure, and the actin filaments were clear and obvious. The findings demonstrated that S-UNL-E greatly promoted the differentiation and maturation of osteoblasts, and S-UNL-E (2.5 × 10⁸) produced the most favorable effect in differentiation promotion. In conclusion, the present study successfully constructed an S-UNL-E material characterized by high encapsulation and high stability, which could effectively promote osteogenic differentiation and bone formation.

Role of MAPK/JNK signaling pathway on the regulation of biological behaviors of MC3T3‑E1 osteoblasts under titanium ion exposure

The oral cavity is a complex environment that is constantly undergoing remodeling. This provides a favorable electrolytic aqueous condition, which causes the corrosion of titanium implants and the release of titanium (Ti) ions. The accumulation of Ti ions in the peri-implant tissues may affect the osteogenesis process. Therefore, the present study aimed to investigate the possible effects of Ti ions on osteoblast physiology and its underlying mechanism, specifically the MAPK/JNK signaling pathway. In the present study, MC3T3-E1 osteoblasts were cultured the medium containing 10 ppm Ti ions. Confocal laser scanning microscopy was used to analyze cell morphology and adhesion. Alkaline phosphatase (ALP) activity assay and western blotting were performed to evaluate the expression of proteins associated with osteogenesis such as Runx2 and Osterix. Nuclear translocation of JNK, a key factor of the MAPK signaling pathway, was visualized and analyzed using immunofluorescence staining. The results showed that 10 ppm Ti ions exerted negative effects on the biological behaviors of MC3T3-E1 cells, which exhibited reduced adhesion, ALP activity and osteogenic differentiation. It was also found that 10 ppm Ti ions activated the MAPK/JNK signaling pathway by promoting the nuclear translocation of JNK via phosphorylation. In addition, the inhibitory effects of 10 ppm Ti ions on MC3T3-E1 cells was found to be reversed by the JNK inhibitor SP600125. In conclusion, the preset study suggests that the MAPK/JNK signaling pathway serves a key role in the molecular mechanism underlying the changes in osteoblast behavior following Ti ion exposure. These findings may serve as a valuable reference point for the further in-depth exploration of peri-implant bone loss.

Scutellarin Ameliorates Renal Injury via Increasing CCN1 Expression and Suppressing NLRP3 Inflammasome Activation in Hyperuricemic Mice

Considerable evidences have indicated that elevated uric acid (UA) was involved in renal tubular injury leading to hyperuricemic nephropathy (HN). Scutellarin is a biologically active flavonoid derived from the Chinese traditional herb Erigeron breviscapus Hand-Mazz, which has been widely used in the treatment of cardiovascular and cerebrovascular diseases. In the present study, we analyzed the effect of scutellarin on HN, by using C57BL/6 mice and human renal tubular epithelial cell line HK-2 which was subjected to adenine/potassium oxonate and UA to mimic a HN injury. The HN mice showed a significant decrease in renal function with the increased SCr and blood urea nitrogen (BUN) (p < 0.05). Hematoxylin–eosin staining results showed a histological injury in HN mice kidney tissues with severe tubular damage. Scutellarin dose dependently alleviated the renal injury of the HN model (p < 0.05), and a dose of 20 mg/kg/day remarkably reduced the Scr level (26.10 ± 3.23 μmol/ml vs. 48.39 ± 7.51 μmol/ml, p < 0.05) and BUN (151.12 ± 30.24 mmol/L vs. 210.43 ± 45.67 mmol/L, p < 0.05) compared with the HN model group. Similarly, scutellarin decreased NGAL, Kim-1, cystatin C, and IL-18 protein expression levels in HN mouse (p < 0.05). Overexpressed CCN1 could not induce NLRP3 inflammasome activation, with no change of mRNA and protein expression levels of NLRP3, ASC, and pro-caspase-1 compared with the control HK-2. However, HK-2 showed a significant NLRP3 inflammasome activation and apoptosis. Importantly, knockdown of CCN1 not only aggravated NLRP3 inflammasome activation and apoptosis but also abrogated the protective effect of scutellarin in UA-induced HK-2 injury. Thus, scutellarin might alleviate HN progression via a mechanism involved in CCN1 regulation on NLRP3 inflammasome activation.

Inhibitory effects of biochanin A on titanium particle-induced osteoclast activation and inflammatory bone resorption via NF-κB and MAPK pathways

Revision operations have become a new issue after successful artificial joint replacements, and periprosthetic osteolysis leading to prosthetic loosening is the main cause of why the overactivation of osteoclasts (OCs) plays an important role. The effect of biochanin A (BCA) has been examined in osteoporosis, but no study on the role of BCA in prosthetic loosening osteolysis has been conducted yet. In this study, we utilised enzyme-linked immunosorbent assay, computed tomography imaging, and histological analysis. Results showed that BCA downregulated the secretion levels of tumor necrosis factor-α, interleukin-1α (IL-1α), and IL-1β to suppress inflammatory responses. The secretion levels of receptor-activated nuclear factor-κB ligand, CTX-1, and osteoclast-associated receptor as well as Ti-induced osteolysis were also reduced. BCA effectively inhibited osteoclastogenesis and suppressed hydroxyapatite resorption by downregulating OC-related genes in vitro. Analysis of mechanisms indicated that BCA inhibited the signalling pathways of mitogen-activated protein kinase (P38, extracellular signal-regulated kinase, and c-JUN N-terminal kinase) and nuclear factor-κB (inhibitor κB-α and P65), thereby downregulating the expression of nuclear factor of activated T cell 1 and c-Fos. In conclusion, BCA may be an alternative choice for the prevention of prosthetic loosening caused by OCs.

Fibroblast-Like-Synoviocytes Mediate Secretion of Pro-Inflammatory Cytokines via ERK and JNK MAPKs in Ti-Particle-Induced Osteolysis

Biomaterials are designed to replace and augment living tissues in order to provide functional support to skeletal deformities. However, wear debris produced from the interfaces of metal implants initiates inflammatory bone loss, causing periprosthetic osteolysis. Lately, fibroblast-like synoviocytes (FLS) have been shown to play a role in wear-debris-induced osteolysis. Thus, here we have tried to understand the underlying mechanism of FLS involvement in wear-debris-induced osteolysis. Our results demonstrate that the effects of Ti particle (1:100 cell-to-Ti particle ratio) on FLS can induce Cox-2 expression and activate NFkB signaling. Moreover, the mRNA expression of pro-inflammatory cytokines such as IL-6, IL-8, IL-11, IL-1β, and TNFα was found to be elevated. However, among these pro-inflammatory cytokines, the mRNA and protein levels of only IL-6, IL-1β, and TNFα were found to be significantly higher. Ti particles activated extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinases (MAPKs) as an early response in FLS. Co-inhibition of ERK and JNK signaling pathways by their specific inhibitors (PD9805 and SP600125, respectively) resulted in the suppression of mRNA and protein levels of IL-6, IL-1β, and TNFα in FLS. Taken together, targeting ERK and JNK MAPKs in FLS might provide a therapeutic option for reducing the secretion of bone-resorbing pro-inflammatory cytokines, thus preventing periprosthetic osteolysis.

Pyropia yezoensis Extract Suppresses IFN-Gamma- and TNF-Alpha-Induced Proinflammatory Chemokine Production in HaCaT Cells via the Down-Regulation of NF-κB

Pyropia yezoensis, a red alga, is popular and harvested a lot in East Asia and is famous for its medicinal properties attributable to its bioactive compounds including amino acids (porphyra-334 and shinorine, etc.), polysaccharides, phytosterols, and pigments, but its anti-inflammatory effect and mechanism of anti-atopic dermatitis (AD) have not been elucidated. In this study, we investigate the anti-AD effect of P. yezoensis extract (PYE) on mRNA and protein levels of the pro-inflammatory chemokines, thymus, and activation-regulated chemokine (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22), in human HaCaT keratinocyte cells treated to interferon (IFN)-γ or tumor necrosis factor (TNF)-α (10 ng/mL each). The effect of the PYE on extracellular signal-regulated kinase (ERK) and other mitogen-activated protein kinases (MAPKs) was related to its suppression of TARC and MDC production by blocking NF-κB activation in HaCaT cells. Furthermore, astaxanthin and xanthophyll from P. yezoensis were identified as anti-AD candidate compounds. These results suggest that the PYE may improve AD and contained two carotenoids by regulating pro-inflammatory chemokines.

Tussilagone Inhibits Osteoclastogenesis and Periprosthetic Osteolysis by Suppressing the NF-κB and P38 MAPK Signaling Pathways

Background

Aseptic prosthetic loosening is one of the main factors causing poor prognosis of limb function after joint replacement and requires troublesome revisional surgery. It is featured by wear particle-induced periprosthetic osteolysis mediated by excessive osteoclasts activated in inflammatory cell context. Some natural compounds show antiosteoclast traits with high cost-efficiency and few side effects. Tussilagone (TUS), which is the main functional extract from Tussilago farfara generally used for relieving cough, asthma, and eliminating phlegm in traditional medicine has been proven to appease several RAW264.7-mediated inflammatory diseases via suppressing osteoclast-related signaling cascades. However, whether and how TUS can improve aseptic prosthetic loosening via modulating osteoclast-mediated bone resorption still needs to be answered.

Methods

We established a murine calvarial osteolysis model to detect the preventative effect of TUS on osteolysis in vivo. Micro-CT scanning and histomorphometric analysis were used to determine the variation of bone resorption and osteoclastogenesis. The anti–osteoclast-differentiation and anti–bone-resorption bioactivities of TUS in vitro were investigated using bone slice resorption pit evaluation, and interference caused by cytotoxicity of TUS was excluded according to the CCK-8 assay results. Quantitative polymerase chain reaction (qPCR) analysis was applied to prove the decreased expression of osteoclast-specific genes after TUS treatment. The inhibitory effect of TUS on NF-κB and p38 MAPK signaling pathways was testified by Western blot and NF-κB-linked luciferase reporter gene assay.

Results

TUS better protected bones against osteolysis in murine calvarial osteolysis model with reduced osteoclasts than those in the control group. In vitro studies also showed that TUS exerted antiosteoclastogenesis and anti–bone-resorption effects in both bone marrow macrophages (BMMs) and RAW264.7 cells, as evidenced by the decline of osteoclast-specific genes according to qPCR. Western blotting revealed that TUS treatment inhibited IκBα degradation and p38 phosphorylation.

Conclusions

Collectively, our studies proved for the first time that TUS inhibits osteoclastogenesis by suppressing the NF-κB and p38 MAPK signaling pathways, therefore serving as a potential natural compound to treat periprosthetic osteolysis-induced aseptic prosthetic loosening.

Crocin inhibits titanium particle-induced inflammation and promotes osteogenesis by regulating macrophage polarization

Wear particle-induced periprosthetic inflammatory osteolysis and resultant aseptic loosening are major causes of orthopedic implant failure, for which there are no effective treatments other than revision surgery. Crocin, a carotenoid compound derived from crocus flowers, has anti-inflammatory properties, but its immunomodulatory function and role in particle-induced osteolysis are not well characterized. Here we report the effect of crocin on titanium (Ti) particle-induced macrophage polarization and osteogenic differentiation. We found that crocin induced anti-inflammatory (M2) macrophage polarization and attenuated Ti particle-induced inflammation by promoting the expression of anti-inflammatory cytokines in vitro as well as in vivo in a mouse air-pouch model. Additionally, crocin pre-treated macrophages promoted osteogenic differentiation of co-cultured mouse bone mesenchymal stem cells (BMSCs). These effects were mediated via inhibition of p38 and c-Jun N-terminal kinase signaling. Our results indicate that crocin suppresses Ti particle-induced inflammation and enhances osteogenic differentiation of BMSCs by inducing M2 macrophage polarization, highlighting its therapeutic potential for preventing wear particle-induced osteolysis.

Rhododendron album Blume extract inhibits TNF-α/IFN-γ-induced chemokine production via blockade of NF-κB and JAK/STAT activation in human epidermal keratinocytes

Rhododendron album Blume (RA) has traditionally been used as an herbal medicine and is considered to have anti‑inflammatory properties. It is a well‑known medicine for treatment of allergic or atopic diseases. In the present study, the biological effects of an RA methanol extract (RAME) on inflammation were investigated in tumor necrosis factor‑α (TNF‑α)/interferon‑γ (IFN‑γ)‑stimulated human keratinocytes. The present study aimed to investigate the potential mechanisms by which RAME inhibited TNF‑α/IFN‑γ‑induced expression of chemokines [thymus‑ and activation-regulated chemokine (TARC) and macrophage‑derived chemokine (MDC)] and cytokines [interleukin (IL)‑6 and IL‑8] through the nuclear factor‑κB (NF‑κB) pathway in human keratinocytes. The effects of RAME treatment on cell viability were investigated in TNF‑α/IFN‑γ‑stimulated HaCaT cells. The expression of TARC, MDC, IL‑6 and IL‑8 was assessed using reverse transcription‑quantitative polymerase chain reaction analysis or ELISA, and its effect on the inhibitory mitogen-activated protein kinase pathway was also studied using western blot analysis. TNF‑α/IFN‑γ induced the expression of IL‑6, IL‑8, TARC and MDC in a dose‑dependent manner through NF‑κB and Janus kinase/signal transducers and activators of transcription (JAK/STAT) activation. Notably, treatment with RAME significantly suppressed TNF-α/IFN-γ-induced expression of IL‑6, IL‑8, TARC, and MDC. In addition, RAME treatment inhibited the activation of NF‑κB and the JAK/STAT pathway in TNF‑α/IFN‑γ‑induced HaCaT cells. These results suggest that RAME decreases the production of chemokines and pro‑inflammatory cytokines by suppressing the NF‑κB and the JAK/STAT pathways. Consequently, RAME may potentially be used for treatment of atopic dermatitis.

Scutellarin Suppresses NLRP3 Inflammasome Activation in Macrophages and Protects Mice against Bacterial Sepsis

The NLRP3 inflammasome plays a critical role in mediating the innate immune defense against pathogenic infections, but aberrant activation of NLRP3 inflammasome has been linked to a variety of inflammatory diseases. Thus targeting the NLRP3 inflammasome represents a promising therapeutic for the treatment of such diseases. Scutellarin is a flavonoid isolated from Erigeron breviscapus (Vant.) Hand.-Mazz. and has been reported to exhibit potent anti-inflammatory activities, but the underlying mechanism is only partly understood. In this study, we aimed to investigate whether scutellarin could affect the activation of NLRP3 inflammasome in macrophages. The results showed that scutellarin dose-dependently reduced caspase-1 activation and decreased mature interleukin-1β (IL-1β) release in lipopolysaccharide (LPS)-primed macrophages upon ATP or nigericin stimulation, indicating that scutellarin inhibited NLRP3 inflammasome activation in macrophages. Consistent with this, scutellarin also suppressed pyroptotic cell death in LPS-primed macrophages treated with ATP or nigericin. ATP or nigericin-induced ASC speck formation and its oligomerization were blocked by scutellarin pre-treatment. Intriguingly, scutellarin augmented PKA-specific phosphorylation of NLRP3 in LPS-primed macrophages, which was completely blocked by selective PKA inhibitor H89, suggesting that PKA signaling had been involved in the action of scutellarin to suppress NLRP3 inflammasome activation. Supporting this, the inhibitory effect of scutellarin on NLRP3 inflammasome activation was completely counteracted by H89 or adenyl cyclase inhibitor MDL12330A. As NLRP3-dependent release of IL-1β has a critical role in sepsis, the in vivo activity of scutellarin was assayed in a mouse model of bacterial sepsis, which was established by intraperitoneally injection of a lethal dose of viable Escherichia coli. Oral administration of scutellarin significantly improved the survival of mice with bacterial sepsis. In line with this, scutellarin treatment significantly reduced serum IL-1β levels and attenuated the infiltration of inflammatory cells in the liver of E. coli-infected mice. These data indicated that scutellarin suppressed NLRP3 inflammasome activation in macrophages by augmenting PKA signaling, highlighting its potential therapeutic application for treating NLRP3-related inflammatory diseases.

Synthesis and Bioactivity Characterization of Scutellarein Sulfonated Derivative

Scutellarin (1) has been widely used to treat acute cerebral infarction in clinic, but poor aqueous solubility decreases its bioavailability. Interestingly, scutellarin (1) could be metabolized into scutellarein (2) in vivo. In this study, a sulfonic group was introduced at position C-8 of scutellarein (2) to enhance the aqueous solubility of the obtained derivative (3). DPPH (1,1-diphenyl-2-picrylhydrazyl)-radical scavenging ability and antithrombic activity were also conducted to determine its bioactivity. The result showed that scutellarein derivate (3) could be a better agent for ischemic cerebrovascular disease treatment.