Tougu Xiaotong capsule promotes chondrocyte autophagy by regulating the Atg12/LC3 conjugation systems

Knowledge mapping of autophagy in osteoarthritis from 2004 to 2022: A bibliometric analysis

Background

Autophagy in osteoarthritis (OA) has become an active area of research with substantial value and potential. Nevertheless, few bibliometric studies have systematically analyzed the available research in the field. The main goal of this study was to map the available literature on the role of autophagy in OA and identify global research hotspots and trends.

Methods

The Web of Science Core Collection and Scopus databases were interrogated for studies of autophagy in OA published between 2004 and 2022. Microsoft Excel, VOSviewer and CiteSpace software were used to analyze and visualize the number of publications and associated citations, and reveal global research hotspots and trends in the autophagy in OA field.

Results

732 outputs published by 329 institutions from 55 countries/regions were included in this study. From 2004 to 2022, the number of publications increased. China produced the most publications (n=456), prior to the USA (n=115), South Korea (n=33), and Japan (n=27). Scripps Research Institute (n=26) was the most productive institution. Martin Lotz (n=30) was the highest output author, while Caramés B (n=302) was the highest output author. Osteoarthritis and Cartilage was the most prolific and most co-cited journal. Currently, the autophagy in OA research hotspots include chondrocyte, transforming growth factor beta 1 (TGF-β1), inflammatory response, stress, and mitophagy. The emerging research trends in this field are AMPK, macrophage, senescence, apoptosis, tougu xiaotong capsule (TXC), green tea extract, rapamycin, and dexamethasone. Novel drugs targeting specific molecule such as TGF-β and AMPK have shown therapeutic potential but are still in the preclinical stage of development.

Conclusions

Research on the role of autophagy in OA is flourishing. Martin Lotz, Beatriz Caramés, and Osteoarthritis and Cartilage have made outstanding contributions to the field. Prior studies of OA autophagy mainly focused on mechanisms underlying OA and autophagy, including AMPK, macrophages, TGF-β1, inflammatory response, stress, and mitophagy. Emerging research trends, however, are centered around the relationship between autophagy, apoptosis, and senescence, as well as drug candidates such as TXC and green tea extract. The development of new targeted drugs that enhance or restore autophagic activity is a promising strategy for the treatment of OA.

The Role of Autophagy in Osteoarthritis

Chondrocytes are the only cell type in normal cartilage. The pathological changes of osteoarthritis (OA) mostly revolve around the apoptosis and dysfunction of chondrocytes. Autophagy, as an intracellular degradation system that maintains the steady state of energy metabolism in cells, has been shown to restore the function of damaged chondrocytes, alleviating the occurrence and progression of OA. In this review, we explored the relationship between autophagy and OA and the key molecules of autophagy pathway that regulate the progression of OA, providing new ideas for OA treatment by targeting autophagy.

Tougu Xiaotong capsules may inhibit p38 MAPK pathway-mediated inflammation: In vivo and in vitro verification

ETHNOPHARMACOLOGICAL RELEVANCE

Tougu Xiaotong capsules (TXC) are an herbal compound commonly used to treat osteoarthritis (OA) in China.

AIM OF THE STUDY

We attempted to verify TXC's therapeutic effects and mechanisms related to the p38 mitogen-activated protein kinase (MAPK) pathway in vivo and in vitro.

MATERIALS AND METHODS

TXC's therapeutic effects were assessed by observing cartilage degeneration and inflammatory factors in a modified Hulth's model (in vivo) and a lipopolysaccharides (LPS)-exposed cellular model (in vitro). The expression of biomarkers related to p38 MAPK pathway-mediated inflammation was also investigated.

RESULTS

TXC treatment reversed cartilage degeneration related biomarkers (ADAMTS 4, ADAMTS 5, Col I, Col V, MMP 3, MMP 9, and MMP 13) and inflammation factors (IL-1β, TNF-α, and IL-6) in both the animal and cellular OA models. Expression of p-p38 MAPK was downregulated following TXC administration, and changes to microRNAs in the cellular models were recovered. These results indicated that the p38 MAPK pathway-related mechanism may involve therapeutic effects of TXC.

CONCLUSIONS

This study verified TXC's efficacy to treat OA in vivo and in vitro and suggests that p38 MAPK pathway-related mechanisms may be involved in TXC's therapeutic effects.

Comparison of kidney-tonifying and blood-activating medicinal herbs vs NSAIDs in patients with knee osteoarthritis: A protocol for a systematic review and meta-analysis

BACKGROUND

Knee osteoarthritis (KOA) is one of the most common chronic muscular diseases in old people. In recent years, people are more and more interested in the use of Chinese herbal medicine (CHM) in the treatment of KOA, such as kidney-tonifying and blood-activating medicinal herbs (KTBAMs) in the treatment of KOA. Many studies have confirmed that KTBAMs are effective in the treatment of KOA. However, it is still unknown whether KTBAMs and NSAIDs are more effective in the treatment of KOA. Therefore, we evaluated the efficacy and safety of KTBAMs and NSAIDs in the treatment of KOA.

METHODS

Randomized controlled trials (RCTs) from online databases including PubMed, Embase, the Cochrane Library, China National Knowledge Infrastructure, Chinese Scientific Journal Database, Wanfang Data, and Chinese Biomedical Literature Database that compared the efficacy of KTBAMs and NSAIDs in the treatment of KOA were retrieved. The main outcomes included the evaluation of functional outcomes, pain and adverse effects. The Cochrane risk of bias (ROB) tool was used to assess methodological quality.

RESULTS

The literature will provide a high-quality analysis of the current evidence supporting KTBAMs for KOA based on various comprehensive assessments including the total effective rate, visual analog scale scores, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lequence scores, Knee Society Scale (KSS) scores, and adverse effects.

CONCLUSION

This proposed systematic review will provide up-to-date evidence to assess the effect of KTBAMs in the treatment for patients with KOA. RESEARCH REGISTRY REGISTRATION NUMBER: : reviewregistry 783.

Are Kidney-Tonifying and Blood-Activating Medicinal Herbs Better than NSAIDs for Knee Osteoarthritis? A Systematic Review and Meta-Analysis

Objective

To compare the efficacy and safety of kidney-tonifying and blood-activating medicinal herbs (KTBAMs) and nonsteroidal anti-inflammatory drugs (NSAIDs) in the treatment of knee osteoarthritis (KOA).

Methods

Randomized controlled trials (RCTs) from online databases that compared the efficacy of KTBAMs and NSAIDs in the treatment of KOA were retrieved. The main outcomes included the evaluation of functional outcomes, pain, and adverse effects. The Cochrane risk-of-bias (ROB) tool was used to assess methodological quality.

Results

A total of 38 RCTs (3994 participants) were included in our meta-analysis. We found that KTBAMs had a significantly higher total effective rate (P < 0.00001, risk ratio (RR) = 1.08, confidence interval (CI) = 1.05 to 1.11, I² = 4%) and a lower gastrointestinal adverse reaction rate (P < 0.00001, RR = 0.36, CI = 0.24 to 0.53, I² = 33%) than NSAIDs. KTBAMs showed greater improvements in the Knee Society Scale (KSS) scores (mean difference (MD) = 7.17, 95% CI 0.71 to 13.64, P=0.03). Regarding the visual analog scale (VAS) scores, WOMAC scores, and Lequence scores, there were no significant differences between the KTBAM group and the NSAID group. The GRADE quality level of this systematic review indicated that the very low-quality evidence showed that KTBAMs had a higher total effective rate, while the moderate-quality evidence showed that the adverse reactions of KTBAMs were lower and the KSS scores were higher. Low-quality evidence showed no significant differences in improving VAS scores, WOMAC scores, or Lequence scores.

Conclusion

KTBAMs were superior to NSAIDs in terms of a higher total effective rate, a lower adverse reaction rate, and a higher KSS score. There were no significant differences between KTBAMs and NSAIDs in improving VAS scores, WOMAC scores, and Lequence scores of patients with KOA. Therefore, KTBAMs may be an alternative effective method for treating KOA. However, high-quality, well-designed RCTs with long-term follow-up are still required.

BMP2-mediated PTEN enhancement promotes differentiation of hair follicle stem cells by inducing autophagy

The proliferation and differentiation of hair follicle stem cells (HFSCs) is regulated by several signaling pathways, including BMP and PTEN. Therefore, this study intended to clarify the potential effects of two such regulators, BMP2 and PTEN, on HFSC differentiation. HFSCs were subjected to BMP2, noggin (BMP2 ligand inhibitor), rapamycin (Rapa, autophagy inducer), 3-methyladenine (3-MA, autophagy inhibitor), or shRNA against PTEN. The differentiation of HFSCs was evaluated using oil red O staining and autophagy was assessed using the transmission electron microscope. Then expression of epidermal differentiation marker (K10 and involucrin), adipogenic markers (PPAR-γ2, aP2, perilipin2, and Adipoq), keratinocyte-specific marker (K15), proliferation-related markers (PCNA and Ki67) and autophagy-related factors (Atg5, Atg7, Atg12, Beclin-1 and LC3-II/LC3-I) was examined by RT-qPCR and Western blot analysis. Next, HFSCs were treated with 3-MA, or shRNA against Atg5 or Atg7 to verify the effect of autophagy on differentiation of BMP2-treated HFSCs. Finally, the effect of BMP2 on HFSC differentiation was verified by a mouse wound model. HFSCs overexpressing BMP2 exhibited elevated expression of epidermal differentiation marker, adipogenic markers and autophagy-related factors but inhibited expression of keratinocyte-specific marker and proliferation-related markers. Furthermore, we found that PTEN promoted the differentiation of BMP2-treated HFSCs by inducing autophagy. In vivo experiments further confirmed the roles of BMP2/PTEN on differentiation of HFSCs. Taken together, BMP2 up-regulated PTEN and consequently induced autophagy to facilitate HFSC differentiation.

An in vitro validation of the therapeutic effects of Tougu Xiaotong capsule on tunicamycin-treated chondrocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Tougu Xiaotong capsule (TXC) is a Chinese herbal compound that belongs to a range of Chinese herbs functioning as 'kidney invigorators and liver softeners' commonly used to treat osteoarthritis (OA) in China.

AIMS OF THE STUDY

The aims of the present study are to confirm the therapeutic effects of TXC in an OA cell model and to determine the mechanisms involved in such effects.

MATERIALS AND METHODS

A tunicamycin (Tm)-exposed OA cell model was employed, and the effects of TXC were confirmed by observing cell viability and apoptosis. The reduced cell viability and increased apoptosis caused by Tm were improved by TXC, confirming the cellular protection of TXC. We then investigated the expression of biomarkers related to the endoplasmic reticulum (ER) stress pathway, including microRNA-211 (miR-211), a regulator in the ER stress pathway.

RESULTS

Downregulation of X-box binding protein 1 (Xbp-1) and miR-211 expression following Tm administration was reversed by TXC. Moreover, the upregulation by Tm of the expression levels of binding immunoglobulin protein, Xbp-1, activating transcription factor 4, C/EBP-homologous protein, Caspase-9 and Caspase-3 was downregulated by TXC. These results indicated that the ER stress pathway-related mechanism may play a potential role in the therapeutic effects of TXC.

CONCLUSIONS

The present study provides evidence of the therapeutic effects of TXC at the cell level and describes a cellular model for establishing the mechanisms of the effects of TXC used in the treatment of OA.

Effectiveness and Safety of Manufactured Chinese Herbal Formula for Knee Osteoarthritis: Insights from a Systematic Review

Objective. To assess the current clinical evidence of manufactured Chinese herbal formulae (MCHF) for knee osteoarthritis (KOA). Methods. Seven databases were searched from inception to May 2015. Eligible randomized controlled trials investigating the effectiveness of MCHF for KOA were included. Data extraction, methodological assessment, and meta-analyses were conducted according to the Cochrane standards. Results. A total of 17 kinds of MCHF were identified from the twenty-six included trials. Meta-analyses showed that MCHF significantly relieved the global pain of knee joints, either used alone or combined with routine treatments. Additionally, MCHF plus routine treatments significantly decreased the scores of WOMAC and Lequesne index. However, there were no statistical differences between MCHF group and routine treatment group in walk-related pain and WOMAC scores. No significant differences were found in Lysholm scores. There were twenty-one trials that mentioned adverse events. A pooled analysis showed that adverse events occurred more frequently in control group compared with MCHF group. Conclusions. Our results indicated that MCHF showed some potential benefits for KOA. However, we still cannot draw firm conclusions due to the poor methodological quality of included trials. More high-quality RCTs would help to confirm the evidence.

Protective effects of Tougu Xiaotong capsule on tumor necrosis factor-α-injured UMR-106 cells

Tumor necrosis factor-α (TNF-α) plays an important role in the abnormal metabolism of osteoblasts (OBs), which leads to subchondral bone (SB) alterations in osteoarthritis. In the present study, Tougu Xiaotong capsule (TXC), a traditional Chinese medicine, was used to treat TNF-α-injured OB-like cells. The cellular viability, mortality and ultramicroscopic morphology were evaluated. Thereafter, the activity of alkaline phosphatase (ALP), secretion of osteocalcin (OCN) and mineralization of nodules were analyzed. The results showed that TXC treatment significantly promoted cell proliferation, reduced cellular mortality and improved cellular ultrastructure, particularly that of the endoplasmic reticulum and nucleus. These data indicate that TXC is able to promote cell growth, as well as prevent inflammation in OB-like cells. Furthermore, the activity of ALP, secretion of OCN and mineralization of nodules were accelerated, and the calcium content of the TNF-α-injured OB-like cells was promoted by TXC treatment. These results indicate that TXC protected the OB-like cells from TNF-α-induced injuries. This may be a potential mechanism through which TXC regulates SB remodeling in the clinical treatment of osteoarthritis.

Biomarkers of Chondrocyte Apoptosis and Autophagy in Osteoarthritis

Cell death with morphological and molecular features of apoptosis has been detected in osteoarthritic (OA) cartilage, which suggests a key role for chondrocyte death/survival in the pathogenesis of OA. Identification of biomarkers of chondrocyte apoptosis may facilitate the development of novel therapies that may eliminate the cause or, at least, slow down the degenerative processes in OA. The aim of this review was to explore the molecular markers and signals that induce chondrocyte apoptosis in OA. A literature search was conducted in PubMed, Scopus, Web of Science and Google Scholar using the keywords chondrocyte death, apoptosis, osteoarthritis, autophagy and biomarker. Several molecules considered to be markers of chondrocyte apoptosis will be discussed in this brief review. Molecular markers and signalling pathways associated with chondroycte apoptosis may turn out to be therapeutic targets in OA and approaches aimed at neutralizing apoptosis-inducing molecules may at least delay the progression of cartilage degeneration in OA.