StemRegenin 1 attenuates the RANKL-induced osteoclastogenesis via inhibiting AhR-c-src-NF-κB/p-ERK MAPK-NFATc1 signaling pathway.

The aryl hydrocarbon receptor (AhR) pathway may play an important role in the regulation of osteoclasts, but there are still conflicting studies on this aspect, and the specific mechanism of action has not been fully elucidated. Therefore, we conducted this study to find a drug to treat osteoporosis that targets AhR. We found that StemRegenin 1 inhibited RANKL-induced osteoclastogenesis in a concentration-dependent and time-dependent manner. Through further experiments, we found that SR1 can inhibit nuclear transcription of AhR and inhibit c-src phosphorylation, and ultimately regulates the activation of the NF-κB and p-ERK/mitogen-activated protein kinase pathways. Therefore, for the first time, we discovered the way in which the AhR-c-src-NF-κB/p-ERK MAPK-NFATc1 signaling pathway regulates the expression of osteoclast differentiation-associated proteins. Finally, SR1 was shown to successfully reverse bone loss in OVX mice. These studies provide us with ideas for finding new way to treat osteoporosis.

Circular RNA circARPC1B functions as a stabilisation enhancer of Vimentin to prevent high cholesterol-induced articular cartilage degeneration.

BACKGROUND: Osteoarthritis (OA) is a prevalent and debilitating condition, that is, directly associated with cholesterol metabolism. Nevertheless, the molecular mechanisms of OA remain largely unknown, and the role of cholesterol in this process has not been thoroughly investigated. This study aimed to investigate the role of a novel circular RNA, circARPC1B in the relationship between cholesterol and OA progression. METHODS: We measured total cholesterol (TC) levels in the synovial fluid of patients with or without OA to determine the diagnostic role of cholesterol in OA. The effects of cholesterol were explored in human and mouse chondrocytes in vitro. An in vivo OA model was also established in mice fed a high-cholesterol diet (HCD) to explore the role of cholesterol in OA. RNAseq analysis was used to study the influence of cholesterol on circRNAs in chondrocytes. The role of circARPC1B in the OA development was verified through circARPC1B overexpression and knockdown. Additionally, RNA pulldown assays and RNA binding protein immunoprecipitation were used to determine the interaction between circARPC1B and Vimentin. CircARPC1B adeno-associated virus (AAV) was used to determine the role of circARPC1B in cholesterol-induced OA. RESULTS: TC levels in synovial fluid of OA patients were found to be elevated and exhibited high sensitivity and specificity as predictors of OA diagnosis. Moreover, elevated cholesterol accelerated OA progression. CircARPC1B was downregulated in chondrocytes treated with cholesterol and played a crucial role in preserving the extracellular matrix (ECM). Mechanistically, circARPC1B is competitively bound to the E3 ligase synoviolin 1 (SYVN1) binding site on Vimentin, inhibiting the proteasomal degradation of Vimentin. Furthermore, circARPC1B AAV infection alleviates Vimentin degradation and OA progression caused by high cholesterol. CONCLUSIONS: These findings indicate that the cholesterol-circARPC1B-Vimentin axis plays a crucial role in OA progression, and circARPC1B gene therapy has the opportunity to provide a potential therapeutic approach for OA.

Tetrandrine inhibits RANKL-induced osteoclastogenesis by promoting the degradation of TRAIL.

BACKGROUND: Tetrandrine, a bisbenzylisoquinoline (BBI) alkaloid extracted from Stephania tetrandra (S. Moore), and is widely used in several diseases such as tuberculosis, hyperglycemia, malaria, and tumors. Tetrandrine was recently shown to prevent bone loss in ovariectomized mice. However, the specific mechanism underlying osteoclastogenesis inhibition remains unclear. METHODS: Tetrandrine's cytotoxicity to cells was determined using the Cell Counting Kit-8 assay. Tartrate-resistant acid phosphatase staining, immunofluorescence and bone resorption assay were performed to evaluate osteoclasts' differentiation and absorption capacity. The bone-forming capacity was assessed using alkaline phosphatase and Alizarin red S staining. qPCR and Western blotting were applied to assess the related genes and protein expression. Tetrandrine's impact on TRAIL was demonstrated through a co-immunoprecipitation assay. Animal experiments were performed for the detection of the therapeutic effect of Tetrandrine on osteoporosis. RESULTS: Tetrandrine attenuated RANKL-induced osteoclastogenesis and decreased the related gene expression. The co-immunoprecipitation assay revealed that Tetrandrine administration accelerated the ubiquitination of TNF-related apoptosis-inducing ligand (TRAIL), which was subsequently degraded. Moreover, TRAIL overexpression was found to partially reverse the Tetrandrine-induced inhibition of osteoclastogenesis. Meanwhile, Tetrandrine significantly inhibited the phosphorylation of p38, p65, JNK, IKBα and IKKα/ß, while the TRAIL overexpression weakened this effect. In addition, Tetrandrine promoted osteogenesis and inhibited the TRAIL expression in osteoblasts. Tetrandrine consistently improved bone destruction by stimulating bone formation and inhibiting bone resorption in an OVX-induced mouse model. CONCLUSION: Tetrandrine inhibits RANKL-induced osteoclastogenesis by promoting TRAIL degradation and promotes osteoblast differentiation, suggesting its potential in antiosteopenia pharmacotherapy.

Nail changes in pemphigus and bullous pemphigoid: A single-center study in China.

Common autoimmune bullous diseases (AIBDs) include pemphigus and bullous pemphigoid (BP), which are primarily caused by IgG autoantibodies against the structural proteins of desmosomes at the cell-cell junction and hemidesmosomes at the epidermal-dermal junction. Few studies have assessed nail changes in patients with pemphigus or BP. In the present study, we collected the clinical data of 191 patients with AIBDs (108 patients with pemphigus and 83 patients with BP) and 200 control subjects. Nail changes were observed in 77.0% (147/191), 77.8% (84/108), and 75.9% (63/83) of patients with AIBDs, pemphigus, and BP, respectively, and 14.5% (29/200) of control subjects. Beau's lines and paronychia were the most common nail involvement, observed in 22.5% (43/191) and 22.5% (43/191) of patients with AIBDs, 25.0% (27/108) and 25.9% (28/108) of patients with pemphigus, 19.3% (16/83) and 18.1% (15/83) of patients with BP, respectively. The autoimmune bullous skin disorder intensity score (ABSIS) and the onset time of patients with pemphigus or BP with nail changes were different. Onychomycosis accounted for 21.5% (41/191) of all patients with AIBDs. The ABSIS was correlated with nail involvement in patients with BP (r = 0.46, p < 0.001), and weakly correlated with nail involvement in patients with AIBDs (r = 0.37, p < 0.001), pemphigus (r = 0.29, p = 0.009), and pemphigus vulgaris (PV; r = 0.35, p = 0.008). No correlation was observed between nail involvement and disease antibody titers. In conclusion, nail changes are frequently observed in patients with pemphigus and BP. The type and onset time of nail changes may indicate the severity of pemphigus and BP, which warrants the attention of dermatologists.

MCU Inhibitor Ruthenium Red Alleviates the Osteoclastogenesis and Ovariectomized Osteoporosis via Suppressing RANKL-Induced ROS Production and NFATc1 Activation through P38 MAPK Signaling Pathway.

Osteoporosis is a disorder of bone metabolism that is extremely common in elderly patients as well as in postmenopausal women. The main manifestation is that the bone resorption capacity is greater than the bone formation capacity, which eventually leads to a decrease in bone mass, increasing the risk of fracture. There is growing evidence that inhibiting osteoclast formation and resorption ability can be effective in treating and preventing the occurrence of osteoporosis. Our study is the first time to explore the role of the mitochondrial calcium uniporter (MCU) and its inhibitor ruthenium red (RR) in bone metabolism, clarifying the specific mechanism by which it inhibits osteoclast formation in vitro and plays a therapeutic role in osteoporosis in vivo. We verified the suppressive effects of RR on the receptor activator of nuclear factor-κB ligand (RANKL-)-induced differentiation and bone resorption function of osteoclasts in vitro. The reactive oxygen species (ROS) production stimulated by RANKL and the expression level of P38 MAPK/NFATc1 were also found to be inhibited by RR. Moreover, the promotion of RR on osteogenesis differentiation was investigated by alkaline phosphatase (ALP) and alizarin red S (ARS) staining and the detection of osteogenesis-specific gene expression levels by quantitative polymerase chain reaction (qPCR) and western blotting. Moreover, in ovariectomy (OVX-)-induced osteoporosis models, RR can downregulate the expression and function of the MCU, relieving bone loss and promoting osteogenesis to present a therapeutic effect on osteoporosis. This new finding will provide an important direction for the study of RR and MCU in the study of bone metabolism therapy targets.

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.

Thermo-responsive injectable naringin-loaded hydrogel polymerised sodium alginate/bioglass delivery for articular cartilage.

In the human body, joint cartilage is of great importance. It has long been a big therapeutic problem to fix joint cartilage lesions as it appears due to different conditions. Recent stories have shown that the cartilage replacement process must delay the extracellular (ECM) cartilage deterioration and modulate the host's inflammation response. For the reconstruction of the articular cartilage, drug-loaded injectable hydrogels were developed. This hydrogel could retain the chondrocyte phenotype, but the host's inflammatory reaction could also be controlled. The bioglass (BG)/sodium alginate (SA) injectable hydrogels was combined with agarose (AG)/Naringin hydrogel in injectable thermal response for articular cartilage regeneration with a non-chargeable hydrogel that contains both Naringin and BG (Naringin-BG hydrogels). The Naringin-BG hydrogel has an adequate swelling ratio that encourages the fusion of tissue formed with host tissue and enables the gradual release of Naringin bioavailabilities enhanced in situ. The Naringin-BG hydrogel can upgrade the typical chondrocyte phenotype by upregulating aggrecan, SRY-box 9, and collagen type II alpha one chain. It may also stimulate the polarization of M2 macrophage, lower inflammations, and prevent ECM degradations through the decrease of the expressions of the indictable metalloproteinase-13 matrix, nitric oxide synthase, and metalloproteinase-1 matrix. The formed tissues were identical to normal tissues and firmly incorporated with the surrounding tissue after administering the Naringin-BG hydrogels into the rat model articular cartilage defects. Then the injectable Naringin-BG hydrogel increases the bioavailable content of Naringin and retains the chondrocyte phenotype.

Sclareol inhibits RANKL-induced osteoclastogenesis and promotes osteoblastogenesis through promoting CCN1 expression via repressing the MAPK pathway.

Osteoclasts are crucial cellular components of bone and are the cause of various bone problems like osteoporosis. Various biological activities such as anti-tumorous, anti-inflammatory, antibacterial, and immunomodulatory function are influenced by Sclareol, as a natural diterpene compound. However, studies on the effect and mechanism of Sclareol on osteoporosis are rare. In the current research, the influence of Sclareol on osteoclastogenesis and osteoblastogenesis was targeted to be discovered in ovariectomy (OVX)-induced animal models and in vitro. The expression levels of osteoclast-related genes such as c-Fos, NFATc1, and CTSK were detected by RT-qPCR and western blotting to understand the inhibition of Sclareol on the creation of osteoclast. The influence of Sclareol on osteoblastogenesis and the expression of osteoblastogenic markers were also examined. Sclareol inhibited the osteoclastogenesis caused by receptor activator of nuclear factor-κB ligand (RANKL) which promoted osteoblastogenesis through upregulating the expression of cysteine-rich protein 61 (CYR61/CCN1), which is a matricellular protein of the CCN family. The p-ERK and p-P38 protein expression levels were considerably downregulated by Sclareol. Furthermore, CCN1 overexpression partially mimicked the inhibitory effect of Sclareol, while the opposite results were obtained after CCN1 silencing. Additionally, Sclareol protected against loss of bones in an osteoporosis mouse model generated by OVX. The acquired results indicated that Sclareol represses RANKL-induced osteoclastogenesis and promotes osteoblastogenesis via promoting the expression of CCN1 by constraining the mitogen-activated protein kinase (MAPK) pathway. Our findings proposed that for the avoidance and treatment of osteoclast-linked disorders, Sclareol is a potentially effective drug. A proposed model for mediated regulation of osteoclastogenesis and osteoblastogenesis by Sclareol. The basic model of the process by which Sclareol prevents osteoclastogenesis and promotes osteoblastogenesis. Sclareol may increase the expression of CCN1 through inhibiting the MAPK pathway, thereby inhibiting osteoclast differentiation and attenuating bone resorption. Sclareol represses the expression of c-Fos, which stimulates the formation of osteoclast. In contrast, Sclareol promotes osteoblast differentiation by upregulating Runx2 expression, thereby improving the formation of bones. Consequently, Sclareol protects against loss of bones by regulating the stability of bone makeover via inhibition of bone formation and stimulation of bone resorption. Graphical Headlights 1. Sclareol represses RANKL-induced osteoclastogenesis. 2. Sclareol promotes osteoblast differentiation. 3. Sclareol inhibits the MAPK pathway through induction of CCN1. 4. Sclareol protects against bone loss by regulating the balance of bone remodeling via inhibition of bone formation and stimulation of bone resorption.

Sensitive simultaneous determination of three sulfanilamide artificial sweeters by capillary electrophoresis with on-line preconcentration and contactless conductivity detection.

A sensitive method followed by capillary electrophoresis with on-line perconcentration and capacitively coupled contactless conductivity detection (CE-C(4)D) was evaluated as a novel approach for the determination of three sulfanilamide artificial sweeteners (acesulfame-K, sodium saccharin and sodium cyclamate) in beverages. The on-line preconcentration technique, namely field-amplified sample injection, coupled with CE-C(4)D were successfully developed and optimized. The separation was achieved within 10 min under the following conditions: an uncoated fused-silica capillary (45 cm × 50 µm i.d., Leff=40 cm), 20 mmol L(-1) HAc as running buffer, separation voltage of -12 kV, electrokinetic injection of -11 kV × 8 s. The detection limits of acesulfame-K, sodium saccharin and sodium cyclamate were 4.4, 6.7 and 8.8 µg L(-1), respectively. The relative standard deviation varied in the range of 3.0-5.0%. Results of this study show a great potential method for the fast screening of these artificial sweeteners contents in commercial beverages.