Yiqi Huoxue Recipe Delayed Intervertebral Disc Degeneration by Activating Autophagy

Palmitic acid and trans-4-hydroxy-3-methoxycinnamate, the active ingredients of Yaobishu formula, reduce inflammation and pain by regulating gut microbiota and metabolic changes after lumbar disc herniation to activate autophagy and the Wnt/β-catenin pathway

The imbalance in gut microbiota triggers an inflammatory response that spreads from the gut to the discs and is associated with lumbar disc herniation (LDH). In this study, we investigated the mechanism of palmitic acid (PA) and trans-4-hydroxy-3-methoxycinnamic acid (THMC) on microbiota, metabolic homeostasis, and autophagy after LDH. The LDH rat model was established by puncturing the exposed intervertebral disc. 16S rDNA was used to assess the gut microbiome composition. The microbial metabolites were analyzed by UPLC-MS. The mechanism of PA and THMC in LDH was explored by fecal microbiota transplantation (FMT). We found that Yaobishu, PA, THMC, and the positive control drug Celebrex attenuated intervertebral disc damage in LDH rats and downregulated TRPV1, IL-1β, and IL-18 expression. In addition, Yaobishu reduced Oscillospirales and Ruminococcaceae abundances after LDH. PA increased Bacilli's abundance while decreasing Negativicutes and Ruminococcaceae abundances. Metabolomics showed that Yaobishu increased 2-hexanone, methyl isobutyl ketone, 2-methylpentan-3-one, and nonadecanoic acid levels but decreased pantetheine and urocanate levels. PA and THMC reduced uridine and urocanate levels. Yaobishu, PA, and THMC activated autophagy and the Wnt/β-catenin pathway in LDH rats. Moreover, antibiotics abrogated these effects. FMT-PA and FMT-THMC activated autophagy and decreased IL-1β, IL-18, Wnt1, β-catenin, and TRPV1 expression. FMT-PA and FMT-THMC partially reversed the effects of 3-MA. Taken together, our data suggest that Yaobishu, PA, and THMC relieve inflammation and pain by remodeling the gut microbiota and restoring metabolic homeostasis after LDH to activate autophagy and the Wnt/β-catenin pathway, which provide a new therapeutic target for LDH in the clinic.

Sesamin-mediated high expression of BECN2 ameliorates cartilage endplate degeneration by reducing autophagy and inflammation

Lumbar disc degeneration (LDD) is a prevalent clinical spinal disease characterized by the calcification and degeneration of the cartilage endplate (CEP), which significantly reduces nutrient supply to the intervertebral disc. Traditional Chinese medicine offers a conservative and effective approach for treating LDD. We aimed to investigate the molecular mechanisms underlying the therapeutic effects of Sesamin in LDD treatment. Transcriptome sequencing was used to analyze the effect of Sesamin on LPS-induced ATDC5. We explored the role of BECN2, a target gene of Sesamin, in attenuating LPS-induced degeneration of ATDC5 cells. Our results revealed the identification of 117 differentially expressed genes (DEGs), with 54 up-regulated and 63 down-regulated genes. Notably, Sesamin significantly increased the expression of BECN2 in LPS-induced ATDC5 cell degeneration. Overexpressed BECN2 enhanced cell viability and inhibited cell apoptosis in LPS-induced ATDC5 cells, while BECN2 knockdown reduced cell viability and increased apoptosis. Furthermore, BECN2 played a crucial role in attenuating chondrocyte degeneration by modulating autophagy and inflammation. Specifically, BECN2 suppressed autophagy by reducing the expression of ATG14, VPS34, and GASP1, and alleviated the inflammatory response by decreasing the expression of inflammasome proteins NLRP3, NLRC4, NLRP1, and AIM2. In vivo experiments further supported the beneficial effects of Sesamin in mitigating LDD. This study provides novel insights into the potential molecular mechanism of Sesamin in treating LDD, highlighting its ability to mediate autophagy and inflammation inhibition via targeting the BECN2. This study provides a new therapeutic strategy for the treatment of LDD, as well as a potential molecular target for LDD.

Role of Autophagy and Pyroptosis in Intervertebral Disc Degeneration

Intervertebral disc degeneration is a chronic degenerative disease caused by the interaction of genetic and environmental factors, mainly manifested as lower back pain. At present, the diagnosis of intervertebral disc degeneration mainly relies on imaging. However, early intervertebral disc degeneration is usually insidious, and there is currently a lack of relevant clinical biomarkers that can reliably reflect early disease progression. Pyroptosis is a regulatory form of cell death triggered by the activation of inflammatory bodies and caspase, which can induce the formation of plasma membrane pores and cell swelling or lysis. Previous studies have shown that during the progression of intervertebral disc degeneration, sustained activation of inflammasomes leads to nuclear cell pyroptosis, which can occur in the early stages of intervertebral disc degeneration. Moreover, intervertebral disc nucleus pulposus cells adapt to the external environment through autophagy and maintain cellular homeostasis and studying the mechanism of autophagy in IDD and intervening in its pathological and physiological processes can provide new ideas for the clinical treatment of IDD. This review analyzes the effects of pyroptosis and autophagy on IDD by reviewing relevant literature in recent years, in order to explore the relationship between pyroptosis, autophagy and IDD.

Achilles' Heel-The Significance of Maintaining Microenvironmental Homeostasis in the Nucleus Pulposus for Intervertebral Discs

The dysregulation of intracellular and extracellular environments as well as the aberrant expression of ion channels on the cell membrane are intricately linked to a diverse array of degenerative disorders, including intervertebral disc degeneration. This condition is a significant contributor to low back pain, which poses a substantial burden on both personal quality of life and societal economics. Changes in the number and function of ion channels can disrupt the water and ion balance both inside and outside cells, thereby impacting the physiological functions of tissues and organs. Therefore, maintaining ion homeostasis and stable expression of ion channels within the cellular microenvironment may prove beneficial in the treatment of disc degeneration. Aquaporin (AQP), calcium ion channels, and acid-sensitive ion channels (ASIC) play crucial roles in regulating water, calcium ions, and hydrogen ions levels. These channels have significant effects on physiological and pathological processes such as cellular aging, inflammatory response, stromal decomposition, endoplasmic reticulum stress, and accumulation of cell metabolites. Additionally, Piezo 1, transient receptor potential vanilloid type 4 (TRPV4), tension response enhancer binding protein (TonEBP), potassium ions, zinc ions, and tungsten all play a role in the process of intervertebral disc degeneration. This review endeavors to elucidate alterations in the microenvironment of the nucleus pulposus during intervertebral disc degeneration (IVDD), with a view to offer novel insights and approaches for exploring therapeutic interventions against disc degeneration.

Mechanism of the Mitogen-Activated Protein Kinases/Mammalian Target of Rapamycin Pathway in the Process of Cartilage Endplate Stem Cell Degeneration Induced by Tension Load

STUDY DESIGN

Basic Research.

OBJECTIVE

Intervertebral disc degeneration (IVDD) is caused by the cartilage endplate (CEP). Cartilage endplate stem cell (CESC) is involved in the recovery of CEP degeneration. Tension load (TL) contributes a lot to the initiation and progression of IVDD. This study aims to investigate the regulatory mechanism of the Mitogen-activated protein kinases/Mammalian target of rapamycin (MAPK/mTOR) pathway during TL-induced CESC degeneration.

METHODS

CESCs were isolated from New Zealand big-eared white female rabbits (6 months old). FX-4000T cell stress loading system was applied to establish a TL-induced degeneration model of CESCs. Western blotting was used to detect the level of mTOR pathway-related proteins and autophagy markers LC3-Ⅱ, Beclin-1, and p62 in degenerative CESCs. The expression of MAPK pathway-related proteins JNK and extracellular signal-regulated kinases (ERK) in degenerated CESCs was inhibited by cell transfection to explore whether JNK and ERK play a regulatory role in TL-induced autophagy in CESCs.

RESULTS

In the CESC degeneration model, the mTOR pathway was activated. After inhibition of mTOR, the autophagy level of CESCs was increased, and the degeneration of CESCs was alleviated. The MAPK pathway was also activated in the CESC degeneration model. Inhibition of JNK expression may alleviate TL-induced CEP degeneration by inhibiting Raptor phosphorylation and activating autophagy. Inhibition of ERK expression may alleviate TL-induced CEP degeneration by inhibiting mTOR phosphorylation and activating autophagy.

CONCLUSION

Inhibition of JNK and ERK in the MAPK signaling family alleviated TL-induced CESC degeneration by inhibiting the phosphorylation of Raptor and mTOR in the mTOR pathway.

Systemic pharmacology reveal the mechanism by which the Qiangjin Zhuanggu Qufeng mixture inhibits LPS-induced pyroptosis of rat nucleus pulposus cells

OBJECTIVE

Low back pain (LBP) is a worldwide health issue primarily attributed to intervertebral disc degeneration (IVDD). Qiangjin Zhuang Qufeng mixture (QJZG), an approved hospital-based formula with years of clinical application, has demonstrated notable therapeutic effects in the treatment of LBP. Nevertheless, the underlying mechanism by which it alleviates LBP remains uncertain.

METHODS

The bioactive constituents of QJZG were initially identified using ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS). Subsequently, network pharmacology was employed to explore the core components and targets. In vivo and in vitro experiments were then conducted to validate the specific mechanism of action of QJZG based on the identified targets and pathways. Following that, ultra-high-performance liquid chromatography/mass spectrometry combined with 16S rRNA gene sequencing of blood and faecal samples was utilized to assess the impact of gut microbiota on faecal and serum metabolites subsequent to QJZG administration in intervertebral disc degeneration (IVDD) rats.

RESULTS

The principal constituents of QJZG were identified using UPLC-Q-TOF-MS/MS, revealing a substantial enrichment of flavonoids and triterpenes. Network pharmacology analysis indicated the potential inhibitory effects of QJZG on the NLRP3 inflammasome and downstream inflammatory factors. Furthermore, investigations demonstrated that intervertebral disc degeneration may be attributed to pyroptotic cell death within the nucleus pulposus. In vitro experiments were performed utilizing LPS to induce the inflammatory response in nucleus pulposus cells (NPC), and it was observed that QJZG-containing serum significantly suppressed key pyroptosis-related genes and downstream inflammatory factors. Additionally, in vivo experiments substantiated the capacity of QJZG to preserve disc height and ameliorate the progression of disc degeneration. Concurrently, oral pharmacotherapy in animal studies prominently involved the effects of Enterobacteriaceae and Clostridium, closely intertwined with lipid metabolism.

CONCLUSIONS

QJZG exhibited a delaying effect on IVDD by preserving the equilibrium between extracellular matrix (ECM) synthesis and degradation in NPCs. This effect was achieved through the suppression of NLRP3 inflammasome expression and the prevention of pyroptosis in NPCs.

Role of autophagy in the pathogenesis and regulation of pain

Pain is a ubiquitous and highly concerned clinical symptom, usually caused by peripheral or central nervous injury, tissue damage, or other diseases. The long-term existence of pain can seriously affect daily physical function and quality of life and produce great torture on the physiological and psychological levels. However, the complex pathogenesis of pain involving molecular mechanisms and signaling pathways has not been fully elucidated, and managing pain remains highly challenging. As a result, finding new targets to pursue effective and long-term pain treatment strategies is required and urgent. Autophagy is an intracellular degradation and recycling process that maintains tissue homeostasis and energy supply, which can be cytoprotective and is vital in maintaining neural plasticity and proper nervous system function. Much evidence has shown that autophagy dysregulation is linked to the emergence of neuropathic pain, such as postherpetic neuralgia and cancer-related pain. Autophagy has also been connected to pain caused by osteoarthritis and lumbar disc degeneration. It is worth noting that in recent years, studies on traditional Chinese medicine have also proved that several traditional Chinese medicine monomers involve autophagy in the mechanism of pain relief. Therefore, autophagy can serve as a potential regulatory target to provide new ideas and inspiration for pain management.

Hydroxysafflor Yellow A (HSYA) Protects Endplate Chondrocytes Against IL-1β-Induced Injury Through Promoting Autophagy

Background

Intervertebral disc degeneration (IDD) refers to intractable pain in patients' waist and legs, which is caused by internal structural disorder and degeneration of intervertebral. This disease severely affects the quality-of-life of people. It has been reported that hydroxysafflor yellow A (HSYA), the active ingredient in safflower extract, could inhibit IL-1β-induced apoptosis of endplate chondrocytes. However, the mechanism by which HSYA regulates the occurrence and progression of IDD remains unclear.

Methods

Rat endplate chondrocytes were isolated from the intervertebral disc. Next, toluidine blue staining and collagen II immunofluorescence staining were used to identify endplate chondrocytes. Then, MDC staining was used to detect the autophagy of endplate chondrocytes. In addition, Western blot was used to measure the expression of cleaved caspase 3, LC-3I/II and ATG7 in endplate chondrocytes.

Results

IL-1β obviously inhibited the viability and proliferation of endplate chondrocytes, while these phenomena were notably reversed by HSYA. Additionally, HSYA was able to inhibit IL-1β-induced apoptosis of endplate chondrocytes. Moreover, HSYA protected endplate chondrocytes against IL-1β-induced inflammation via inducing autophagy.

Conclusion

HSYA protected rat endplate chondrocytes against IL-1β-induced injury via promoting autophagy. Therefore, the present study might provide some theoretical basis for exploring novel and effective methods for patients with IDD.

Yaobishu Regulates Inflammatory, Metabolic, Autophagic, and Apoptosis Pathways to Attenuate Lumbar Disc Herniation

Objective

Here, we aimed to explore the main mechanism of Yaobishu (YBS) in lumbar disc herniation (LDH).

Methods and Results

Eighteen compounds that might act on LDH were obtained through a combination of network pharmacology prediction and identification by high-performance liquid chromatography-mass spectrometry. The key compounds were palmitic acid and trans-4-hydroxy-3-methoxycinnamate (cinnamate). KEGG analysis demonstrated that palmitic acid target genes mainly regulate the PPAR signaling pathway, Ras signaling pathway, and fatty acid metabolism. Cinnamate target genes were primarily involved in chemical carcinogenesis-receptor activation, lipid and atherosclerosis, the HIF-1 signaling pathway, and nitrogen metabolism. The rat LDH model was constructed using autologous nucleus pulposus tissue implantation. Differential expression gene (DEGs) related to metabolism (CDKN1A and UHRF1), inflammation (S100A9 and SOCS3), autophagy (DCN and LEPR), and apoptosis (CTSW and BCL2A1) in dorsal root ganglion (DRG) tissues of the control and LDH groups was evaluated by RNA-Seq. TNF-α stimulated DRG neuronal cells were used to establish an in vitro LDH model. YBS, palmitic acid, and cinnamate reduced the expression of substance P, CGRP, S100A9, CTSW, and cleaved caspase-3, while enhancing the expression of CDKN1A, UHRF1, PCNA, Ki67, SOCS3, DCN, LEPR, and BCL2A1, as well as telomerase activity. Pearson's correlation analysis confirmed that DCN was positively correlated with BCL2A1, indicating that autophagy might be negatively correlated with apoptosis in LDH. YBS, palmitic acid, and cinnamate reduced the Siegal neurological score and serum IL-1β and IL-18 levels, while increasing changes in the hind paw mechanical withdrawal threshold. The RNA-Seq results further showed that YBS downregulated S100A9 and CTSW expression, while upregulating SOCS3, CDKN1A, UHRF1, DCN, LEPR, and BCL2A1 expression.

Conclusion

YBS and its compounds, palmitic acid, and cinnamate, attenuated LDH by regulating the inflammatory, metabolic, autophagic, and apoptotic pathways. Our results might improve the theoretical and experimental basis for clinical applications of LDH disease treatment.

Pulsed Electromagnetic Field Alleviates Intervertebral Disc Degeneration by Activating Sirt1-Autophagy Signaling Network

Intervertebral disc (IVD) degeneration is regarded as a major contributor to low back pain (LBP), causing serious economic burden on individuals and society. Unfortunately, there are limited effective treatment for IVD degeneration. Pulsed electromagnetic field (PEMF) is an economical and effective physical therapy method, with reduced side-effects. It offers certain protection to a number of degenerative diseases. Therefore, understanding the underlying mechanism of PEMF on IVD is important for improving the PEMF therapeutic efficiency. In this study, PEMF up-regulated extracellular matrix (ECM) related genes in degenerated nucleus pulposus (NP) cells. It also increased SIRT1 expression and promoted autophagy in degenerated NP cells. In contrast, the autophagy suppressor 3-methyladenine (3-MA) reversed the beneficial effect of PEMF on ECM production. Similarly, the SIRT1 enzyme activity suppressor EX 527 also inhibited the effect of PEMF on autophagy and ECM production in NP cells, thereby suggesting that PEMF regulated ECM related genes expression through SIRT1-autophagy signaling pathway. Lastly, PEMF significantly reduced IVD degeneration in a rat model of IVD degeneration in vivo. In summary, our study uncovers a critical role of SIRT1-dependent autophagy signaling pathway in ECM protection and thus in the establishment of therapeutic effect of PEMF on IVD degeneration.

USP13: Multiple Functions and Target Inhibition

As a deubiquitination (DUB) enzyme, ubiquitin-specific protease 13 (USP13) is involved in a myriad of cellular processes, such as mitochondrial energy metabolism, autophagy, DNA damage response, and endoplasmic reticulum-associated degradation (ERAD), by regulating the deubiquitination of diverse key substrate proteins. Thus, dysregulation of USP13 can give rise to the occurrence and development of plenty of diseases, in particular malignant tumors. Given its implications in the stabilization of disease-related proteins and oncology targets, considerable efforts have been committed to the discovery of inhibitors targeting USP13. Here, we summarize an overview of the recent advances of the structure, function of USP13, and its relations to diseases, as well as discovery and development of inhibitors, aiming to provide the theoretical basis for investigation of the molecular mechanism of USP13 action and further development of more potent druggable inhibitors.