Toosendanin inhibits osteoclast formation and alleviate postmenopausal osteoporosis by regulating the p38 signaling pathway

UBE2N modulates osteoclast differentiation via BTK-PLCγ2-Ca2+ signaling pathway to promote osteoporosis

Osteoporosis is a prevalent public health issue and the underlying mechanism is an imbalance in bone remodeling. Excessive bone resorption caused by upregulation of osteoclast activity is a key factor in the pathogenesis of osteoporosis. Studies have shown that RNA binding protein (RBP) may play an important role in mechanism of OP through interaction with RNA. It has been reported that ubiquitin conjugating enzyme 2 N (UBE2N), as an RBP, is highly expressed in the clinical samples of osteoporotic patients. However, the role and mechanism of action of UBE2N in the regulation of osteoclast differentiation remain unclear. The aim of this study is to evaluate the effects and mechanisms of UBE2N in promoting osteoclastogenesis. In this study, we demonstrated that UBE2N is notably elevated in patients with osteoporosis. Furthermore, our findings revealed that the interference of UBE2N significantly improves osteoporosis of mice, and impedes osteoclast differentiation and bone resorption both in vitro and in vivo. To investigate the molecular mechanisms by which UBE2N influences osteoclast differentiation and bone resorption, we employed RNA sequencing to investigate its downstream related molecules and established that UBE2N regulated the expression of bruton tyrosine kinase (BTK). More importantly, we found that UBE2N may affect osteoclast differentiation and bone resorption by enhancing the expression of the p-BTK gene, which activates the phospholipase Cγ2 (PLCγ2)-Ca2+ signaling pathway. Based on these findings, our study highlights the potential of UBE2N as a promising therapeutic target for osteoporosis.

Toosendanin promotes prostate cancer cell apoptosis, ferroptosis and M1 polarization via USP39-mediated PLK1 deubiquitination

Toosendanin (TSN) can inhibit the malignant process of many cancers, and has the potential to be developed as an anti-tumor drug. However, the role and mechanism of TSN in prostate cancer (PCa) progression remain unclear. PCa cells (DU145 and LNCaP) were treated with TSN. Cell viability was detected by cell counting kit 8 assay. Cell proliferation, apoptosis and metastasis were assessed by colony formation assay, flow cytometry and transwell assay. Cell ferroptosis was evaluated by examining Fe2+, MDA and lipid-ROS levels. M1 polarization markers were analyzed by flow cytometry. Immunohistochemical staining, quantitative real-time PCR and western blot were used to detect ubiquitin-specific protease 39 (USP39) and polo-like kinase 1 (PLK1) expression. Cycloheximide treatment, Co-IP assay and ubiquitination assay were performed to confirm the regulation of USP39 on PLK1. In vivo experiments were employed to determine the effect of TSN and USP39 on PCa tumor growth. TSN treatment suppressed PCa cell proliferation, cell cycle, migration, and invasion, while enhanced apoptosis, ferroptosis, and M1 polarization. USP39 was upregulated in PCa tissues and cells, and its protein expression was reduced by TSN. USP39 overexpression reversed the regulation of TSN on PCa cell functions. PLK1 had elevated expression in PCa, and USP39 stabilized its protein expression by deubiquitination. USP39 knockdown inhibited PCa cell behaviors, and its regulation was abolished by PLK1 overexpression. Meanwhile, TSN reduced PCa tumor growth by regulating USP39/PLK1. TSN played anti-tumor role in PCa, which promoted PCa cell apoptosis, ferroptosis, and M1 polarization by inhibiting USP39/PLK1 axis.

Targeting p38 MAPK: A potential bridge between ER stress and age-related bone loss

The endoplasmic reticulum (ER) is crucial in the development of numerous age-related bone disorders. Notably, ER stress can precipitate bone loss by orchestrating inflammatory responses, apoptosis, and autophagy through the activation of the p38 MAPK pathway. Age-related bone loss diseases pose a significant burden on society and healthcare as the global population ages. This review provides a comprehensive analysis of recent research advancements, delving into the critical role of ER stress-activated p38 MAPK in inflammation, apoptosis, and autophagy, as well as its impact on bone formation and bone resorption. This review elucidates the molecular mechanisms underlying the involvement of ER stress-activated p38 MAPK in osteoporosis, rheumatoid arthritis, periodontitis, and osteoarthritis and discusses the therapeutic potential of targeting p38 MAPK. Furthermore, this review provides a scientific foundation for new therapeutic strategies by highlighting prospective research directions.

Toosendanin inhibits the growth of Spodoptera litura by inducing metabolic dysfunction in the midgut

The Spodoptera litura, a crucial polyphagous pest, has emerged as a major threat to the agricultural sector. Regrettably, despite ongoing efforts, scientists have yet to uncover a safe and efficient control medication to tackle this pressing issue. Toosendanin (TSN), a commercial insecticidal active ingredient used to manage various pests in the field, has adverse effects on Spodoptera litura. However, the effects of TSN on the midgut of S. litura larvae remain unclear. This study explored the mechanism of TSN-induced toxicity and its inhibitory effects on larval growth and development using intestinal pathology, intestinal digestive enzyme activity determination, and intestinal transcriptome sequencing. The results indicated that TSN treatment led to pathological changes in the midgut structure. Analysis of digestive enzyme activity revealed that TSN inhibited the activities of acetyl CoA carboxylase, lipase, α-amylase, and trypsin. Simultaneously, it upregulated superoxide dismutase and reduced malondialdehyde content. Transcriptome analysis revealed that 2151 genes were significantly differentially expressed in the midgut after TSN exposure; the analysis highlighted significant enrichment of DEGs in areas such as hydrolase activity, carbohydrate metabolism, and peptide metabolism. Notably, some key enzymes involved in lipid metabolism, protein metabolism, and carbohydrate metabolism, such as pancreatic triacylglycerol lipase-like, pancreatic lipid-related protein 2-like, lipase3, alpha-amylase, trypsin, and chymotrypsin were downregulated following TSN treatment. This study's findings suggest that TSN causes midgut damage and inhibits larval growth by inducing metabolic dysfunction in the midgut.

Astragaloside IV attenuates glucocorticoid-induced osteoclastogenesis and bone loss via the MAPK/NF-κB pathway

BACKGROUND

Astragaloside IV (AS-IV) is a bioactive saponin extracted from Radix Astragali, and it is reported to promote osteoblast differentiation while inhibiting osteoclastogenesis. However, the mechanism of AS-IV in glucocorticoid-induced osteoclastogenesis (GIO) remains undetermined. Herein, we examined the influence of AS-IV on GIO and bone loss.

METHODS

RAW264.7 cells were incubated with dexamethasone (Dex) alone or Dex and receptor activator of nuclear factor-B ligand (RANKL) (Dex and RANKL) for 2 days, and then treated with Dex or Dex and RANKL through AS-IV for the timeframes indicated. Following, mice were intraperitoneally administered with an intermediate-acting glucocorticoid, methylprednisolone (MP), or MP and AS-IV for 6 weeks.

RESULTS

AS-IV significantly decreased Dex-induced osteoclast nucleus and area, however, it did not impact the number of Dex-induced osteoclasts in RAW264.7 cells. AS-IV also significantly decreased the osteoclastic marker protein expressions in Dex-induced RAW264.7 cells with concentration of dose dependent fashion. Additionally, AS-IV promoted p38 phosphorylation (p-) and p-p65 translocation to the nucleus, while inhibiting phosphorylation of extracellular signal-regulated kinase (ERK) (p-ERK) and inhibitor of Nuclear factor κB (NF-κB) (p-IκB) levels. However, the AS-IV-mediated action on p-MAPK, p-NF-κB, and osteoclastic marker expressions were reversed by MAPK or IκB inhibitor in Dex-induced RAW264.7 cells. Furthermore, our in vivo evaluation revealed that AS-IV also attenuated the MP-mediated bone loss, and suppressed osteoclastogenesis.

CONCLUSIONS

This study demonstrates that AS-IV inhibits GIO and attenuates bone loss via the MAPK/NF-κB pathway. This also suggested that AS-IV could be a potential promising therapeutic agent for glucocorticoid-triggered bone loss.

Toosendanin inhibits T-cell proliferation through the P38 MAPK signalling pathway

In recent years, immunosuppressants have shown significant success in the treatment of autoimmune diseases. Therefore, there is an urgent need to develop additional immunosuppressants that offer more options for patients. Toosendanin has been shown to have immunosuppressive activity in vitro as well as effects on autoimmune hepatitis (AIH) in vivo. Toosendanin did not induce apoptosis in activated T-cells and affect the survival rate of naive T-cells. Toosendanin did not affect the expression of CD25 or secretion of IL-2 by activated T-cells, and not affect the expression of IL-4 and INF-γ. Toosendanin did not affect the phosphorylation of STAT5, ERK, AKT, P70S6K. However, toosendanin inhibited proliferation of anti-CD3/anti-CD28 mAbs-activated T-cells with IC50 of (10 ± 2.02) nM. Toosendanin arrested the cell cycle in the G0/G1 phase, significantly inhibited IL-6 and IL-17A secretion, promoted IL-10 expression, and inhibited the P38 MAPK pathway. Finally, toosendanin significantly alleviated ConA-induced AIH in mice. In Summary, toosendanin exhibited immunosuppressive activity in vivo and in vitro. Toosendanin inhibits the proliferation of activated T-cells through the P38 MAPK signalling pathway, significantly suppresses the expression of inflammatory factors, enhances the expression of anti-inflammatory factors, and effectively alleviates ConA-induced AIH in mice, suggesting that toosendanin may be a lead compound for the development of novel immunomodulatory agents with improved efficacy and reduced toxicity.

A novel mechanism of Vildagliptin in regulating bone metabolism and mitigating osteoporosis

Osteoporosis has become a global social problem with the tendency toward the aging population. The challenge in managing osteoporosis is to develop new anti-osteoporosis drugs that target bone anabolism. The purpose of this study was to uncover the novel mechanism of Vildagliptin on bone metabolism. We revealed that Vildagliptin significantly promoted osteogenic differentiation of precursor osteoblasts and bone marrow mesenchymal stem cells (BMSCs). At the same time, it significantly enhanced the polarization of RAW264.7 macrophages to the M2 type and the secretion of osteogenic factors BMP2 and TGF-β1. This was confirmed by the increased osteogenic differentiation observed in the osteoblast-RAW264.7 co-culture system. Moreover, Vildagliptin significantly enhanced the transformation of BMSCs into the osteogenic morphology in the osteoblast-BMSC co-culture system. Finally, Vildagliptin also inhibited osteoclastic differentiation of RAW 264.7 cells. The potential mechanism underlying these effects involved targeting the GAS6/AXL/ERK5 pathway. In the in vivo study, Vildagliptin significantly alleviated postmenopausal osteoporosis in ovariectomized mice. These findings represent the first comprehensive revelation of the regulatory effect of Vildagliptin on bone metabolism. Specifically, Vildagliptin demonstrates the ability to promote bone anabolism and inhibit bone resorption by simultaneously targeting osteoblasts, BMSCs, and osteoclasts. The bone-protective effects of Vildagliptin were further confirmed in a postmenopausal osteoporosis model. The clinical significance of this study lies in laying a theoretical foundation for bone protection therapy in type-2 diabetes patients with compromised bone conditions or postmenopausal osteoporosis.

VSIG4 inhibits RANKL-induced osteoclastogenesis by enhancing Nrf2-dependent antioxidant response against reactive oxygen species production

Osteoporosis is a prevalent systemic skeletal disorder, particularly affecting postmenopausal women, primarily due to excessive production and activation of osteoclasts. However, the current anti-osteoporotic drugs utilized in clinical practice may lead to certain side effects. Therefore, it is necessary to further unravel the potential mechanisms regulating the osteoclast differentiation and to identify novel targets for osteoporosis treatment. This study revealed the most significant decline in VSIG4 expression among the VSIG family members. VSIG4 overexpression significantly inhibited RANKL-induced osteoclastogenesis and bone resorption function. Mechanistically, both western blot and immunofluorescence assay results demonstrated that VSIG4 overexpression attenuated the expression of osteoclast marker genes and dampened the activation of MAPK and NF-κB signaling pathways. Furthermore, VSIG4 overexpression could inhibit the generation of reactive oxygen species (ROS) and stimulate the expression of Nrf2 along with its downstream antioxidant enzymes via interaction with Keap1. Notably, a potent Nrf2 inhibitor, ML385, could reverse the inhibitory effect of VSIG4 on osteoclast differentiation. In line with these findings, VSIG4 overexpression also mitigated bone loss induced by OVX and attenuated the activation of osteoclasts in vivo. In conclusion, our results suggest that VSIG4 holds promise as a novel target for addressing postmenopausal osteoporosis. This is achieved by suppressing osteoclast formation via enhancing Nrf2-dependent antioxidant response against reactive oxygen species production.

Recent advances of NFATc1 in rheumatoid arthritis-related bone destruction: mechanisms and potential therapeutic targets

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease characterized by inflammation of the synovial tissue and joint bone destruction, often leading to significant disability. The main pathological manifestation of joint deformity in RA patients is bone destruction, which occurs due to the differentiation and proliferation of osteoclasts. The transcription factor nuclear factor-activated T cell 1 (NFATc1) plays a crucial role in this process. The regulation of NFATc1 in osteoclast differentiation is influenced by three main factors. Firstly, NFATc1 is activated through the upstream nuclear factor kappa-B ligand (RANKL)/RANK signaling pathway. Secondly, the Ca2+-related co-stimulatory signaling pathway amplifies NFATc1 activity. Finally, negative regulation of NFATc1 occurs through the action of cytokines such as B-cell Lymphoma 6 (Bcl-6), interferon regulatory factor 8 (IRF8), MAF basic leucine zipper transcription factor B (MafB), and LIM homeobox 2 (Lhx2). These three phases collectively govern NFATc1 transcription and subsequently affect the expression of downstream target genes including TRAF6 and NF-κB. Ultimately, this intricate regulatory network mediates osteoclast differentiation, fusion, and the degradation of both organic and inorganic components of the bone matrix. This review provides a comprehensive summary of recent advances in understanding the mechanism of NFATc1 in the context of RA-related bone destruction and discusses potential therapeutic agents that target NFATc1, with the aim of offering valuable insights for future research in the field of RA. To assess their potential as therapeutic agents for RA, we conducted a drug-like analysis of potential drugs with precise structures.

Therapeutic potential of toosendanin: Novel applications of an old ascaris repellent as a drug candidate

Toosendanin (TSN), extracted from Melia. toosendan Sieb.et Zucc. and Melia. azedarach L., has been developed into an ascaris repellent in China. However, with the improvement of public health protection, the incidence of ascariasis has been reduced considerably, resulting in limited medical application of TSN. Therefore, it is questionable whether this old ascaris repellent can develop into a drug candidate. Modern studies have shown that TSN has strong pharmacological activities, including anti-tumor, anti-botulinum, anti-viral and anti-parasitic potentials. It also can regulate fat formation and improve inflammation. These researches indicate that TSN has great potential to be developed into a corresponding medical product. In order to better development and application of TSN, the availability, pharmacodynamics, pharmacokinetics and toxicology of TSN are summarized systematically. In addition, this review discusses shortcomings in the current researches and provides useful suggestions about how TSN developed into a drug candidate. Therefore, this paper illustrates the possibility of developing TSN as a medical product, aimed to provide directions for the clinical application and further research of TSN.

Isolation and Characterization of an Anti-Osteoporotic Compound from Melia toosendan Fructus

Melia toosendan fructus, traditionally employed in traditional Chinese and Korean herbal medicine, exhibits diverse biological properties encompassing anti-tumor, anti-inflammatory, and anti-viral effects. However, its influence on bone metabolism remains largely unexplored. In this study, we investigated the impact of an ethanolic extract of Melia toosendan fructus (MTE) on osteoclast differentiation and characterized its principal active constituent in osteoclast differentiation and function, as well as its effects on bone protection. Our findings demonstrate that MTE effectively inhibits the differentiation of osteoclast precursors induced by receptor activator of nuclear factor κB ligand (RANKL). Utilizing a bioassay-guided fractionation approach coupled with UHPLC-MS/MS analysis, we isolated and identified the triterpenoid compound toosendanin (TSN) as the active constituent responsible for MTE's anti-osteoclastogenic activity. TSN treatment downregulated the expression of nuclear factor of activated T cells c1, a pivotal osteoclastogenic transcription factor, along with molecules implicated in osteoclast-mediated bone resorption, including tumor necrosis factor receptor-associated factor 6, carbonic anhydrase II, integrin beta-3, and cathepsin K. Furthermore, treatment of mature osteoclasts with TSN impaired actin ring formation, acidification, and resorptive function. Consistent with our in vitro findings, TSN administration mitigated trabecular bone loss and reduced serum levels of the bone resorption marker, C-terminal cross-linked telopeptides of type I collagen, in a mouse bone loss model induced by intraperitoneal injections of RANKL. These results suggest that TSN, as the principal active constituent of MTE with inhibitory effects on osteoclastogenesis, exhibits bone-protective properties by suppressing both osteoclast differentiation and function. These findings imply the potential utility of TSN in the treatment of diseases characterized by excessive bone resorption.

Antioxidant and Wound Healing Bioactive Potential of Extracts Obtained from Bark and Needles of Softwood Species

Interest in the extraction of phytochemical bioactive compounds, especially polyphenols from biomass, has recently increased due to their valuable biological potential as natural sources of antioxidants, which could be used in a wide range of applications, from foods and pharmaceuticals to green polymers and bio-based materials. The present research study aimed to provide a comprehensive chemical characterization of the phytochemical composition of forest biomass (bark and needles) of softwood species (Picea abies L., H. Karst., and Abies alba Mill.) and to investigate their in vitro antioxidant and antimicrobial activities to assess their potential in treating and healing infected chronic wounds. The DPPH radical-scavenging method and P-LD were used for a mechanistic explanation of the biomolecular effects of the investigated bioactive compounds. (+)-Catechin, epicatechin, rutin, myricetin, 4 hydroxybenzoic and p-cumaric acids, kaempherol, and apigenin were the main quantified polyphenols in coniferous biomass (in quantities around 100 µg/g). Also, numerous phenolic acids, flavonoids, stilbenes, terpenes, lignans, secoiridoids, and indanes with antioxidant, antimicrobial, anti-inflammatory, antihemolytic, and anti-carcinogenic potential were identified. The Abies alba needle extract was more toxic to microbial strains than the eukaryotic cells that provide its active wound healing principles. In this context, developing industrial upscaling strategies is imperative for the long-term success of biorefineries and incorporating them as part of a circular bio-economy.