Triptolide inhibits the function of TNF-α in osteoblast differentiation by inhibiting the NF-κB signaling pathway

Triptolide mitigates the inhibition of osteogenesis induced by TNF-α in human periodontal ligament stem cells via the p-IκBα/NF-κB signaling pathway: an in-vitro study

BACKGROUND

Triptolide is a widely utilized natural anti-inflammatory drug in clinical practice. Aim of this study was to evaluate effects of triptolide on hPDLSCs osteogenesis in an inflammatory setting and to investigate underlying mechanisms.

METHODS

Using the tissue block method to obtain hPDLSCs from extracted premolar or third molar. Flow cytometry, osteogenic and adipogenic induction were carried out in order to characterise the features of the cells acquired. hPDLSC proliferative activity was assessed by CCK-8 assay to determine the effect of TNF-α and/or triptolide. The impact of triptolide on the osteogenic differentiation of hPDLSCs was investigated by ALP staining and quantification. Osteogenesis-associated genes and proteins expression level were assessed through PCR and Western blotting assay. Finally, BAY-117,082 was used to study the NF-κB pathway.

RESULTS

In the group treated with TNF-α, there was an elevation in inflammation levels while osteogenic ability and the expression of both osteogenesis-associated genes and proteins decreased. In the group co-treated with TNF-α and triptolide, inflammation levels were reduced and osteogenic ability as well as the expression of both osteogenesis-associated genes and proteins were enhanced. At the end of the experiment, both triptolide and BAY-117,082 exerted similar inhibitory effects on the NF-κB pathway.

CONCLUSION

The osteogenic inhibition of hPDLSCs by TNF-α can be alleviated through triptolide, with the involvement of the p-IκBα/NF-κB pathway in this mechanism.

Exploring the pharmacological mechanism of Tripterygium wilfordii hook for treatment of Behcet's disease using network pharmacology and molecular docking

Tripterygium wilfordii hook (TWH) has been used to treat Behcet's disease (BD) but its underlying mechanism remains unclear. This study aims to explore the mechanism of TWH on BD using network pharmacology and molecular docking. The bioactive constituents of TWH and their corresponding target genes were extracted from the Traditional Chinese Medicine systems pharmacology database and analysis platform. BD target genes were obtained by searching the DisGeNet and GeneCards databases. Gene ontology annotation and Kyoto encyclopedia of genes and genomes pathway enrichment analysis were conducted to elucidate the function of overlapping genes between TWH and BD target genes. A protein-protein interaction network was constructed using Cytoscape and STRING platforms, and the core target genes were identified from the overlapping genes. Finally, molecular docking was used to assess the binding affinity between the core targets and TWH bioactive constituents. We identified 25 intersection genes related to both TWH and BD and 27 bioactive ingredients of TWH. Through analysis of protein-protein interaction network, 6 core targets (TNF, IFNG, prostaglandin-endoperoxide synthase 2, NOS2, VCAM-1, and interleukin-2) were screened out. Enrichment analysis demonstrated that the antioxidant properties of TWH constituents might play a significant role in their therapeutic effects. Molecular docking revealed high binding affinity between the bioactive constituents of TWH, such as kaempferol, triptolide, 5, 8-Dihydroxy-7-(4-hydroxy-5-methyl-coumarin-3)-coumarin, and their corresponding target genes, suggesting the potential of TWH to treat BD. Our investigation clarified the active components, therapeutic targets of BD in the treatment of TWH and provided a theoretical foundation for further researches.

Polysaccharides from aloe vera target the Wnt/β-catenin pathway to impact the tooth density of pulpitis rats

PURPOSE

To investigate the mechanism of polysaccharides from aloe vera (PAV), a main active ingredient of Aloe vera, treatment in pulpitis rats.

METHODS

Pulpitis were modeled by drilling the occlusal central fossa with Sprague Dawley rats. Next, the rats were treated with 20, 40, and 80 mg/kg PAV for three weeks, respectively. Computed tomography scanning assay, hematoxylin and eosin staining, and tartrate-resistant acid phosphatase staining were used to detect the pathology change. Then, levels of tumor necrosis factor-α, interleukin-1β, prostaglandin E2, and ciclooxigenase 2 were detected by enzyme-linked immunosorbent assay. The expressions of bone morphogenetic protein 2 human (BMP-2), osteocalcin, osterix, and runt-related transcription factor 2 (Runx2) were quantified by quantitative real-time polymerase chain reaction and Western blotting (WB). Finally, Wnt3a expression, p-GSK3β/GSK3β and p-β-catenin/β-catenin ratio were analyzed by WB.

RESULTS

PAV up regulated the bone mineral density, and reduced the breakage of the crown and cervical structures, and the necrosis of the crown and root pulp of pulpitis rats. In addition, results indicated that PAV could inhibit osteoblast formation. While osteoblasts' number was decreased, proteins of BMP-2, osteocalcin, osterix, and Runx2 were up-regulated by PAV. Furthermore, PAV increased the Wnt3a expression and the p-β-catenin/β-catenin ratio, and decreased p-GSK3β/GSK3β ratio. Interestingly, these effects were all in dose dependence.

CONCLUSIONS

PAV could inhibit pulp inflammation and promote osteoblasts differentiation via suppressing the activation of the Wnt/β-catenin signaling, enhancing the dental bone density.

Therapeutic Potential of Triptolide in Treating Bone-Related Disorders

Triptolide, a diterpene triepoxide, is a pharmacologically active compound isolated from a Chinese medicinal herb Tripterygium wilfordii Hook F (TwHF). Triptolide has attracted considerable attention in recent times due to its multiple biological and pharmaceutical activities, with an emphasis on therapeutic importance in the treatment of diverse disorders. With essential medicinal implications, TwHF’s extracts have been used as anti-inflammatory, antiproliferative, antioxidative, and immunosuppressive agents for centuries, with continuous and relevant modifications to date to enhance its utility in several diseases and pathophysiology. Here, in this review, we accentuate the studies, highlighting the effects of triptolide on treating bone-related disorders, both inflammatory and cancerous, particularly osteosarcoma, and their manifestations. Based on this review, future avenues could be estimated for potential research strategies, molecular mechanisms, and outcomes that might contribute toward reinforcing new dimensions in the clinical application of triptolide in treating bone-related disorders.

Localization of VEGF, TGF-β1, BMP-2, and Apoptosis Factors in Hypertrophic Nonunion of Human Tubular Bones

We studied localization of VEGF, TGF-β1, BMP-2, caspase-3, Bcl-2, and TNFα in the callus samples obtained from 5 patients (4 women and 1 man) aged 41-53 years during planned surgery for nonunion and pseudarthrosis of the clavicle (n=1), ulna (n=1), femur (n=1), and tibia (n=2) bones. Two control groups included material of hypertrophied callus (n=3) with consolidated fractures of long bones and samples of intact bones (n=3) obtained by postmortem autopsy of subjects without pathology of the musculoskeletal system. A nonuniform distribution of the studied markers was revealed. Active expression of VEGF was observed in fibroblast-like cells of the fibrous tissue, osteoblasts of the periosteum and osteons. Osteoblasts expressing BMP-2 were localized in the periosteum and the loose connective tissue of the Haversian canals. The number of immunopositive cells expressing TGF-β1 and TNFα in the callus exceeded that in the control and correlated with the expression of caspase-3 in fibroblast-like cells, osteoblasts, chondroblasts, and microvascular endotheliocytes. The results allow considering fracture nonunion as a result of overproduction of cytotoxic and proapoptotic factors in chronic inflammation and dysfunction of the expression of morphogenetic proteins. The morphochemical patterns of the studied markers open up prospects for the development of new methods of pharmacological correction of fracture repair.

The roles of signaling pathways in SARS-CoV-2 infection; lessons learned from SARS-CoV and MERS-CoV

The number of descriptions of emerging viruses has grown at an unprecedented rate since the beginning of the 21^st century. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), is the third highly pathogenic coronavirus that has introduced itself into the human population in the current era, after SARS-CoV and Middle East respiratory syndrome coronavirus (MERS-CoV). Molecular and cellular studies of the pathogenesis of this novel coronavirus are still in the early stages of research; however, based on similarities of SARS-CoV-2 to other coronaviruses, it can be hypothesized that the NF-κB, cytokine regulation, ERK, and TNF-α signaling pathways are the likely causes of inflammation at the onset of COVID-19. Several drugs have been prescribed and used to alleviate the adverse effects of these inflammatory cellular signaling pathways, and these might be beneficial for developing novel therapeutic modalities against COVID-19. In this review, we briefly summarize alterations of cellular signaling pathways that are associated with coronavirus infection, particularly SARS-CoV and MERS-CoV, and tabulate the therapeutic agents that are currently approved for treating other human diseases.

Hymenialdisine: A Marine Natural Product That Acts on Both Osteoblasts and Osteoclasts and Prevents Estrogen-Dependent Bone Loss in Mice

Excessive osteoclast (OC) activity together with relatively weak osteoblast (OB) function are strongly connected to osteolytic diseases, including osteoporosis, tumor-induced osteolysis, and inflammatory bone erosion. Very few natural products or compounds have been shown to exert therapeutic effects on both OCs and OBs, limiting the potential development of natural compounds for clinical application. Hymenialdisine (HMD) is a marine sponge-derived natural inhibitor of protein kinases with previously reported anti-osteoarthritis and anti-cancer properties. However, the roles of HMD in OCs, OBs, and osteoporosis have not yet been well established. Here, we found that HMD not only suppressed osteoclastogenesis but also promoted OB differentiation. HMD exerted dose-dependent inhibitory effects on RANKL-induced OC formation, bone resorption, and OC-specific gene expression. These strong inhibitory effects were achieved by blocking the NF-κB and MAPK signaling pathways, and NFATc1 expression. In addition, HMD potentially stimulated OB differentiation by activating alkaline phosphatase (ALP) and enhancing OB matrix mineralization. We found that HMD can activate the glycogen synthase kinase 3β (GSK-3β)/β-catenin/T-cell factor (TCF)/lymphoid enhancer factor (LEF) signaling pathway to upregulate Runx-2 expression, the main transcription factor in this pathway. Increased expression of Runx-2 was also correlated with expression of the OB-specific genes Col1a1 and osteocalcin (Ocn). Furthermore, we also evaluated the therapeutic potential of HMD in a female C57BL/6j mouse model of ovariectomy (OVX)-induced systematic bone loss. HMD showed a remarkable ability to prevent decreases in bone volume (BV/TV) and trabecular thickness (Tb.Th). In summary, HMD exerts notable effects in inhibiting OC-related osteolysis and enhancing OB-induced ossification, suggesting the potential application of HMD in osteoporosis treatment. © 2020 American Society for Bone and Mineral Research.

Discovery of potential targets of Triptolide through inverse docking in ovarian cancer cells

Triptolide (TPL) is proposed as an effective anticancer agent known for its anti-proliferation of a variety of cancer cells including ovarian cancer cells. Although some studies have been conducted, the mechanism by which TPL acts on ovarian cancer remains to be clearly described. Herein, systematic work based on bioinformatics was carried out to discover the potential targets of TPL in SKOV-3 cells. TPL induces the early apoptosis of SKOV-3 cells in a dose- and time-dependent manner with an IC₅₀ = 40 ± 0.89 nM when cells are incubated for 48 h. Moreover, 20 nM TPL significantly promotes early apoptosis at a rate of 40.73%. Using a self-designed inverse molecular docking protocol, we fish the top 19 probable targets of TPL from the target library, which was built on 2,250 proteins extracted from the Protein Data Bank. The 2D-DIGE assay reveals that the expression of eight genes is affected by TPL. The results of western blotting and qRT-PCR assay suggest that 40 nM of TPL up-regulates the level of Annexin A5 (6.34 ± 0.07 fold) and ATP syn thase (4.08 ± 0.08 fold) and down-regulates the level of β-Tubulin (0.11 ± 0.12 fold) and HSP90 (0.21 ± 0.09 fold). More details of TPL affecting on Annexin A5 signaling pathway will be discovered in the future. Our results define some potential targets of TPL, with the hope that this agent could be used as therapy for the preclinical treatment of ovarian cancer.

Ras associated with diabetes may play a role in fracture nonunion development in rats

Background

Rad is the prototypic member of a subfamily of Ras-related small G-proteins and is highly expressed in the skeletal muscle of patients with type II diabetes. Our previous microarray analysis suggested that Rad may mediate fracture nonunion development. Thus, the present study used rat experimental models to investigate and compare the gene and protein expression patterns of both Rad and Rem1, another RGK subfamily member, in nonunions and standard healing fractures.

Methods

Standard healing fractures and nonunions (produced via periosteal cauterization at the fracture site) were created in the femurs of 3-month-old male Sprague-Dawley rats. At post-fracture days 7, 14, 21, and 28, the fracture callus and fibrous tissue from the standard healing fractures and nonunions, respectively, were harvested and screened (via real-time PCR) for Rad and Rem1 expression. The immunolocalization of both encoded proteins was analyzed at post-fracture days 14 and 21. At the same time points, hematoxylin and eosin staining was performed to identify the detailed tissue structures.

Results

Results of real-time PCR analysis showed that Rad expression increased significantly in the nonunions, compared to that in the standard healing fractures, at post-fracture days 14, 21, and 28. Conversely, immunohistochemical analysis revealed the immunolocalization of Rad to be similar to that of Rem1 in both fracture types at post-fracture days 14 and 21.

Conclusions

Rad may mediate nonunion development, and thus, may be a promising therapeutic target to treat these injuries.

Effects Of Triptolide On Tooth Movement And Root Resorption In Rats

Purpose

The aim of this study was to investigate the effects of triptolide on the tooth movement and root resorption in rats during orthodontic treatment.

Material and methods

A total of 48 male Wistar rats were divided into three groups of 16 each. The right maxillary first molars of rats were drawn mesially by closed coil nickel-titanium spring with a force of 50 g. The two experimental groups received intraperitoneal injections of triptolide for 14 days at a dose of 15 µg/kg/day and 30 µg/kg/day, respectively. The control group received vehicle injections. After 14 days, the rats were humanely killed. The amount of tooth movement was measured. Eight rats from each group were randomly chosen for analysis of the percentage of root resorption area by scanning electron microscopy. For the remaining eight rats in each group, the H&E staining, tartrate-resistant acid phosphatase (TRAP) staining and immunohistochemistry analysis were performed.

Results

The amount of tooth movement and the ratio of root resorption area were significantly decreased in the triptolide-treated rats. The number of TRAP-positive cells was significantly lower in triptolide-treated groups. Moreover, the expression of nuclear factor kappa B ligand (RANKL) was reduced. In contrast, the expression of osteoprotegerin was significantly up-regulated. In the tension side, the expressions of runt-related transcription factor 2 and osteocalcin were significantly enhanced by triptolide injection.

Conclusion

Triptolide injection could arrest orthodontic tooth movement and reduce root resorption in rats via inhibition of osteoclastogenesis. In addition, triptolide may exert a positive effect on osteoblastogenesis.

[Effectiveness and mechanism of pure platelet-rich plasma on osteochondral injury of talus]

Objective

To explore the effectiveness and mechanism of pure platelet-rich plasma (P-PRP) on osteochondral injury of talus.

Methods

Thirty-six patients with osteochondral injury of talus selected between January 2014 and October 2017 according to criteria were randomly divided into control group (group A), leukocyte PRP (L-PRP) group (group B), and P-PRP group (group C), with 12 cases in each group. There was no significant difference in gender, age, disease duration, and Hepple classification among the three groups ( P>0.05). Patients in the groups B and C were injected with 2.5 mL L-PRP or P-PRP at the bone graft site, respectively. Patients in the group A were not injected with any drugs. The American Orthopaedic Foot and Ankle Society (AOFAS) score and visual analogue scale (VAS) score were used to evaluate the effectiveness before operation and at 3, 6, and 12 months after operation. Study on the therapeutic mechanism of P-PRP: MC3T3-E1 cells were randomly divided into control group (group A), L-PRP group (group B), and P-PRP group (group C). Groups B and C were cultured with culture medium containing 5% L-PRP or P-PRP respectively. Group A was cultured with PBS of the same content. MTT assay was used to detect cell proliferation; ELISA was used to detect the content of matrix metalloprotein 9 (MMP-9) protein in supernatant; alkaline phosphatase (ALP) activity was measured; and real-time fluorescence quantitative PCR (qRT-PCR) was used to detect the expression of osteopontin (OPN), collagen type Ⅰ, and MMP-9 in cells. Western blot was used to detect the expression of MMP-9 in supernatant and phosphoinositide 3-kinase (PI3K), phosphorylated protein kinase B (pAKT), and phosphorylated c-Jun (p-c-Jun) in cells.

Results

All patients were followed up 13-25 months, with an average of 18 months. No complication such as wound infection and internal fixation failure occurred. MRI showed that the degree of injury was similar between the three groups before operation, and patients in the three groups all recovered at 6 months after operation. Moreover, group C was superior to groups A and B. Compared with preoperation, AOFAS scores and VAS scores in the three groups were all significantly improved at each time point after operation ( P<0.05). AOFAS score of group C was significantly higher than that of groups A and B at 3, 6, and 12 months after operation ( P<0.05); there was no significant difference in VAS score between the three groups ( P>0.05). Study on the therapeutic mechanism of P-PRP: The absorbance ( A) value, ALP activity, the relative mRNA expression of OPN and collagen type Ⅰ in group C were significantly higher than those in groups A and B ( P<0.05), and those in group B were significantly higher than those in group A ( P<0.05). The relative expression of MMP-9 protein and mRNA and the content of MMP-9 protein detected by ELISA in group B were significantly higher than those in groups A and C, while those in group C were significantly lower than those in group A ( P<0.05). Western blot detection showed that the relative expression of PI3K, pAKT, and p-c-Jun protein in group B was significantly higher than those in groups A and C ( P<0.05), but there was no significant difference between groups A and C ( P>0.05).

Conclusion

P-PRP is superior to L-PRP for osteochondral injury of talus, which may be related to the inhibition of PI3K/AKT/AP-1 signaling pathway in the osteoblast, thereby reducing the secretion of MMP-9.

The Effect of Triptolide in Rheumatoid Arthritis: From Basic Research towards Clinical Translation

Triptolide (TP), a major extract of the herb Tripterygium wilfordii Hook F (TWHF), has been shown to exert potent pharmacological effects, especially an immunosuppressive effect in the treatment of rheumatoid arthritis (RA). However, its multiorgan toxicity prevents it from being widely used in clinical practice. Recently, several attempts are being performed to reduce TP toxicity. In this review, recent progress in the use of TP for RA, including its pharmacological effects and toxicity, is summarized. Meanwhile, strategies relying on chemical structural modifications, innovative delivery systems, and drug combinations to alleviate the disadvantages of TP are also reviewed. Furthermore, we also discuss the challenges and perspectives in their clinical translation.

The protective effects of triptolide on age-related bone loss in old male rats

BACKGROUND

Previous studies have showed that triptolide have a critical role in inhibiting osteoclast formation, bone resorption and attenuating regional osteoporosis. However, the protective role of triptolide on age-related bone loss has not been investigated. In the study, we assessed the effect of triptolide supplementation on bone microstructure and bone remolding in old male rat lumbars.

METHODS

Fifty-two 22-month-old male Sprague-Dawley rats were randomly assigned to either triptolide treatment group or control group. Triptolide (15 μg/kg/d) or normal saline was administered to the rats of assigned group for 8 weeks. Lumbar bone mineral density (BMD) and bone microstructure were analyzed by micro-CT. Fluorochrome labeling of the bones was performed to measure the mineral apposition rate (MAR) and bone formation rate (BFR). Osteoclast number was also measured by TRAP staining. Plasma level of osteocalcin and tartrate-resistant acid phosphatase 5b (Tracp 5b) was also analyzed.

RESULTS

Micro-CT results revealed that triptolide-treated rats had significant higher BMD, bone volume over total volume (BV/TV), trabecular thickness (Tb.Th), bone trabecular number (Tb.N), and lower trabecular separation (Tb.Sp) compared to the control group. Although fluorochrome labeling result showed no significant difference in MAR and BFR between the groups, triptolide decreased osteoclast number in vivo. In addition, a significant higher level of plasma Tracp 5b was observed in the triptolide-treated rats. Furthermore, triptolide also reduced the expression of receptor for activation of NF-κB ligand (RANKL) and increased osteoprotegerin (OPG) expression in the lumbars.

CONCLUSION

These results suggested that triptolide had a protective effect on age-related bone loss at least in part by reducing osteoclast number in elder rats. Therefore, triptolide might be a feasible therapeutic approach for senile osteoporosis.