The role of IL-1β and TNF-α in intervertebral disc degeneration

Cytokine Imbalance as a Biomarker of Intervertebral Disk Degeneration

The intervertebral disk degeneration (IDD) and its associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. IDD progresses with age, leading to spondylosis, spondylarthrosis, intervertebral disk herniation, and spinal stenosis. The purpose of this review is an attempt to summarize the data characterizing the patterns of production of pro-inflammatory and anti-inflammatory cytokines in IDD and to appreciate the prognostic value of cytokine imbalance as its biomarker. This narrative review demonstrates that the problem of evaluating the contribution of pro-inflammatory and anti-inflammatory cytokines to the maintenance or alteration of cytokine balance may be a new key to unlocking the mystery of IDD development and new therapeutic strategies for the treatment of IDD in the setting of acute and chronic inflammation. The presented data support the hypothesis that cytokine imbalance is one of the most important biomarkers of IDD.

Biomaterials delivery strategies to repair degenerated intervertebral discs by regulating the inflammatory microenvironment

Intervertebral disc degeneration (IVDD) is one of the leading causes of lower back pain. Although IVDD cannot directly cause death, it can cause pain, psychological burdens, and economic burdens to patients. Current conservative treatments for IVDD can relieve pain but cannot reverse the disease. Patients who cannot tolerate pain usually resort to a strategy of surgical resection of the degenerated disc. However, the surgical removal of IVDD can affect the stability of adjacent discs. Furthermore, the probability of the reherniation of the intervertebral disc (IVD) after surgery is as high as 21.2%. Strategies based on tissue engineering to deliver stem cells for the regeneration of nucleus purposes (NP) and annulus fibrosus (AF) have been extensively studied. The developed biomaterials not only locally withstand the pressure of the IVD but also lay the foundation for the survival of stem cells. However, the structure of IVDs does not provide sufficient nutrients for delivered stem cells. The role of immune mechanisms in IVDD has recently become clear. In IVDD, the IVD that was originally in immune privilege prevents the attack of immune cells (mainly effector T cells and macrophages) and aggravates the disease. Immune regulatory and inflammatory factors released by effector T cells, macrophages, and the IVD further aggravate IVDD. Reversing IVDD by regulating the inflammatory microenvironment is a potential approach for the treatment of the disease. However, the biological factors modulating the inflammatory microenvironment easily degrade in vivo. It makes it possible for different biomaterials to modulate the inflammatory microenvironment to repair IVDD. In this review, we have discussed the structures of IVDs and the immune mechanisms underlying IVDD. We have described the immune mechanisms elicited by different biological factors, including tumor necrosis factors, interleukins, transforming growth factors, hypoxia-inducible factors, and reactive oxygen species in IVDs. Finally, we have discussed the biomaterials used to modulate the inflammatory microenvironment to repair IVDD and their development.

Baicalin suppresses interleukin-1β-induced apoptosis, inflammatory response, oxidative stress, and extracellular matrix degradation in human nucleus pulposus cells

OBJECTIVE

To explore the effect of baicalin on human nucleus pulposus cells (NPCs) in response to interleukin (IL)-1β stimulation.

METHODS

Viability of NPCs was measured by cell counting kit-8 (CCK-8) assay. TUNEL staining assay and flow cytometry were performed to detect apoptotic cell death of NPCs. Western blot analysis was conducted to detect the expression levels of proteins. Enzyme-linked immunosorbent assay (ELISA) was applied for the determination of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor alpha (TNF-α), and IL-6. Oxidative stress indicators including reactive oxygen species (ROS) production, malondialdehyde (MDA) level, and superoxide dismutase (SOD) activity were measured.

RESULTS

Baicalin attenuated IL-1β-caused cell viability reduction and apoptosis in NPCs. IL-1β-induced increase in Bax expression and decrease in Bcl-2 expression were attenuated by baicalin treatment. IL-1β-induced production of iNOS, COX-2, IL-6, and TNF-α in NPCs was inhibited by baicalin treatment. Baicalin treatment reversed IL-1β-induced increase in ROS production and MDA level, as well as decrease in SOD activity. Furthermore, baicalin treatment elevated the expression levels of Col II and Aggrecan and downregulated the expression levels of MMP3, MMP13, and ADAMTS5 in IL-1β-induced NPCs. A total of 402 related targets of baicalin and 134 related targets of intervertebral disk degeneration were found, and nine intersection targets were screened out. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that mitogen-activated protein kinase (MAPK) pathway was found to be involved in the effects of baicalin.

CONCLUSIONS

Baicalin exhibited protective effects on IL-1β-caused cell viability reduction, apoptosis, oxidative stress, inflammation, and extracellular matrix degradation in NPCs. In addition, we found c-Jun N-terminal kinase (JNK) and p38 MAPK pathways as targets of baicalin through bioinformatic analysis.

The effect of ultrasound-guided acupotomy and Juanbi decoction on lumbar disc herniation: A randomized controlled trial

BACKGROUND

Acupotomy as well as Juanbi decoction has been used in the treatment of lumbar disc herniation. However, there is no study on ultrasound-guided acupotomy combined with Juanbi decoction in the treatment of lumbar disc herniation.

METHOD

This study was supported by the Sichuan Provincial Administration of Traditional Chinese Medicine [grant number: 2020LC0163] and the Science and Technology Department of Sichuan Province [grant number: 2022YFS0418]. This study was 3 center, open, randomized, controlled trial, and was carried out from December 2020 to December 2022. A total of 60 eligible patients with LDH were split into group A and group B at random. The group B received Juanbi Decoction 3 times daily for 2 weeks along with an acupotomy assisted by ultrasound. The acupotomy was administered once a week. The same protocol was used with the group A, but the Juanbi Decoction was replaced with normal saline.

OBSERVATION INDEX

Visual analogue scale (VAS) score on 1 day and 1 week after treatment, VAS score, Japanese orthopedic association low back pain score(JOA) rate, Oswestry Disability Index (ODI), and low back outcome scale (LBOS) at 1, 3, 6, and 12 months after treatment in 2 groups.

RESULTS

There were no significant differences in general information, VAS score before treatment, JOA, ODI, and LBOS between the 2 groups (P > .05). Intra-group comparison: VAS score, JOA rate, ODI, and LBOS were compared before and after treatment in both groups, and the differences were statistically significant (P < .05). There were significant differences in VAS and LBOS between the 2 groups at 3 and 6 months after treatment, and there were statistically significant differences in ODI and JOA rates at 3, 6, and 12 months after treatment between the 2 groups.

CONCLUSION

Acupotomy aided by ultrasound combined with Juanbi Decoction significantly relieves lumbar pain and can improve lumbar function in patients with LDH, and the clinical efficacy lasts for about 6 months.

Effects of zinc oxide and condensed tannins on the growth performance and intestinal health of weaned piglets in ETEC-challenged environment

This experiment was conducted to evaluate effects of zine oxide (ZnO) and condensed tannins (CT), independently or in combination, on the growth performance and intestinal health of weaned piglets in enterotoxigenic Escherichia coli (ETEC-K88)-challenged environment. Randomly divided 72 weaned piglets into 4 groups. Dietary treatments included the following: basic diet group (CON), 1,500 mg/kg zinc oxide group (ZnO), 1,000 mg/kg condensed tannins group (CT), and 1,500 mg/kg zinc oxide +1,000 mg/kg condensed tannins group (ZnO + CT). Dietary ZnO supplementation decreased diarrhea rate from 0 to 14 days, 15 to 28 days, and 0 to 28 days (p < 0.05) and no significant on growth performance. The effect of CT on reducing diarrhea rate and diarrhea index was similar to the results of ZnO. Compared with the CON group, ZnO increased the ileum villus height and improved intestinal barrier function by increasing the content of mucin 2 (MUC-2) in jejunum and ileum mucosa and the mRNA expression of zonula occludens-1 (ZO-1) in jejunum (p < 0.05) and the expression of Occludin in duodenum and ileum (p < 0.05). The effects of CT on intestinal barrier function genes were similar to that of ZnO. Moreover, the mRNA expression of cystic fibrosis transmembrane conductance regulator (CFTR) in jejunum and ileum was reduced in ZnO group (p < 0.05). And CT was also capable of alleviating diarrhea by decreasing CFTR expression and promote water reabsorption by increasing AQP3 expression (p < 0.05). In addition, pigs receiving ZnO diet had higher abundance of phylum Bacteroidetes, and genera Prevotella, and lower phylum Firmicutes and genera Lactobacillus in colonic contents. These results indicated that ZnO and CT can alleviate diarrhea and improve intestinal barrier function of weaned pigs in ETEC-challenged environment. In addition, the application of ZnO combined with CT did not show synergistic effects on piglet intestinal health and overall performance. This study provides a theoretical basis for the application of ZnO in weaning piglet production practices, we also explored effects of CT on the growth performance and intestinal health of weaned piglets in ETEC-challenged environment.

Whole-transcriptome sequencing identifies key differentially expressed circRNAs/lncRNAs/miRNAs/mRNAs and linked ceRNA networks in adult degenerative scoliosis

Background

Adult degenerative scoliosis (ADS) is forecast to be a prevalent disabling condition in an aging society. Universally, its pathogenesis is perceived as intervertebral disc degeneration (IDD), however, a thought-provoking issue is why precisely a subset of patients with disc degeneration develop ADS. Exploring the diversities between common IDD and ADS would contribute to unraveling the etiological mechanisms of ADS. Therefore, we aimed to integrate the circRNA, lncRNA, miRNA, and mRNA expression profiles from normal adults (Normal), patients with lumbar disc herniation (LDH), and ADS by whole transcriptome sequencing, which identifies critical functional ncRNA and ceRNA networks and crosstalk between the various transcripts.

Methods

The fresh whole blood samples (n = 3/group) were collected from ADS patients, LDH patients, and healthy volunteers (Normal group), which were examined for mRNA, miRNA, lncRNA, and circRNA expression and screened for differentially expressed (DE) ncRNAs. Then, Gene Ontology (GO) and KEGG analyses were performed for gene annotation and enrichment pathways on the DE RNAs, which were constructed as a lncRNA-miRNA-mRNA network. Eventually, DE RNAs were validated by qRT-PCR targeting disc nucleus pulposus (NP) tissue in ADS and LDH group (n = 10/group).

Results

Compared to the LDH group, we identified 3322 DE mRNAs, 221 DE lncRNAs, 20 DE miRNAs, and 15 DE circRNAs in the ADS. In contrast to Normal, 21 miRNAs and 19 circRNAs were differentially expressed in the ADS. The expression of multiple differentially expressed ncRNAs was confirmed by qRT-PCR analysis to be consistent with the sequencing results. In addition, GO, and KEGG analysis demonstrated that most DE mRNAs and ncRNAs target genes are involved in various biological processes, including Endocytosis, Apoptosis, Rap1 signaling pathway, Notch signaling pathway, and others. The constructed lncRNA-miRNA-mRNA co-expression network was primarily related to angiogenesis and regulation.

Conclusion

By focusing on comparing asymmetric and symmetric disc degeneration, whole-transcriptome sequencing and bioinformatics analysis systematically screened for key ncRNAs in the development of ADS, which provided an abundance of valuable candidates for the elucidation of regulatory mechanisms. The DE ncRNAs and the lncRNA-miRNA-mRNA network are intrinsically involved in the regulation of mediator and angiogenesis, which may contribute to the insight into the pathogenesis of ADS.

Emodin protects against apoptosis and inflammation by regulating reactive oxygen species-mediated NF-κB signaling in interleukin-1β-stimulated human nucleus pulposus cells

Intervertebral disc degeneration (IDD) is a complex degradative disorder associated with inflammation. Emodin, an anthraquinone derivative, possesses strong anti-inflammatory activity. This study focused on the in vitro therapeutic action of emodin in a cellular model of IDD. Human nucleus pulposus cells (NPCs) were stimulated with interleukin-1β (IL-1β) to induce inflammation. Cell Counting Kit-8 and terminal deoxynucleotidyl transferase dUTP nick end labeling staining assays were performed to evaluate the viability and apoptosis of NPCs, respectively. Caspase-3 activity was measured to indirectly assess cell apoptosis. Western blot analysis was performed to detect protein expression levels. Reverse transcription-polymerase chain reaction was performed for the detection of relative mRNA levels of tumor necrosis factor-α (TNF-α) and IL-6. Enzyme-linked immunosorbent assay was performed to analyze TNF-α and IL-6 secretion. Our results showed that emodin treatment mitigated IL-1β-induced reduction of cell viability in NPCs. Moreover, the increase in reactive oxygen species (ROS) production, apoptotic rate, and caspase-3 activity in IL-1β-stimulated NPCs was reduced by emodin treatment. Treatment with emodin also abolished IL-1β-induced inflammation in NPCs, as indicated by reduced secretion of IL-6 and TNF-α. Besides, the increase in expression levels of phosphorylated p65 and nuclear p65 in IL-1β-stimulated NPCs was suppressed by emodin treatment. Furthermore, inhibition of nuclear factor kappa B (NF-κB) activation with pyrrolidine dithiocarbamate aggravated the protective effects of emodin. These results suggested that emodin protected NPCs against IL-1β-induced apoptosis and inflammation via inhibiting ROS-mediated activation of NF-κB.

Identification of mitochondria-related key gene and association with immune cells infiltration in intervertebral disc degeneration

Intervertebral disc (IVD) degeneration and its inflammatory microenvironment can result in discogenic pain, which has been shown to stem from the nucleus pulposus (NP). Increasing evidence suggests that mitochondrial related genes are strictly connected to cell functionality and, importantly, it can regulate cell immune activity in response to damaged associated signals. Therefore, identification of mitochondria related genes might offer new diagnostic markers and therapeutic targets for IVD degeneration. In this study, we identified key genes involved in NP tissue immune cell infiltration during IVD degeneration by bioinformatic analysis. The key modules were screened by weighted gene co-expression network analysis (WCGNA). Characteristic genes were identified by random forest analysis. Then gene set enrichment analysis (GSEA) was used to explore the signaling pathways associated with the signature genes. Subsequently, CIBERSORT was used to classify the infiltration of immune cells. Function of the hub gene was confirmed by PCR, Western blotting and ELISA. Finally, we identified MFN2 as a crucial molecule in the process of NP cell pyroptosis and NLRP3 inflammasome activation. We speculate that the increased MFN2 expression in NP tissue along with the infiltration of CD8⁺ T cells, NK cell and neutrophils play important roles in the pathogenesis of IVD degeneration.

Maltol ameliorates intervertebral disc degeneration through inhibiting PI3K/AKT/NF-κB pathway and regulating NLRP3 inflammasome-mediated pyroptosis

OBJECTIVES

As one of the major causes of low back pain, intervertebral disc degeneration (IDD) has caused a huge problem for humans. Increasing evidence indicates that NLRP3 inflammasome-mediated pyroptosis of NP cells displays an important role in the progression of IDD. Maltol (MA) is a flavoring agent extracted from red ginseng. Due to its anti-inflammatory and antioxidant effects, MA has been widely considered by researchers. Therefore, we hypothesized that MA may be a potential IVD protective agent by regulating NP cells and their surrounding microenvironment.

METHODS

In vitro, qRT-PCR, and Western blot were used to explore the effect of MA on the transcription and protein expression of the anabolic protein (ADAMTS5, MMP3, MMP9) catabolic protein (Aggrecan), and pro-inflammatory factor (iNOS COX-2). Next, the effects of MA on PI3K/AKT/NF-κB pathway and pyroptosis pathway were analyzed by Western blot and immunofluorescence. Molecular docking was used to investigate the relationship between PI3K and MA. Moreover, ELISA was also used to detect the effects of MA on inflammatory factors (TNF-α, PGE2, IL-1β, and IL-18). In vivo, the effects of MA on the vertebral structure of IDD mice were studied by HE and SO staining and the effects of MA on ECM and PI3K/AKT/NF-κB and pyroptosis pathway of IDD mice were studied by immunohistochemical staining.

RESULTS

MA can ameliorate intervertebral disc degeneration in vivo and in vitro. Specifically, the molecular docking results showed that the binding degree of MA and PI3K was significant. Second, in vitro studies showed that MA inhibited the degradation of ECM and inflammatory response by inhibiting the PI3K/AKT/NF-κB pathway and the pyroptosis mediated by NLRP3 inflammasome, which increased the expression of anabolic proteins, decreased the expression of catabolic proteins, and decreased the secretion of inflammatory mediators such as IL-18 and IL-1β. In addition, according to the study results of the mouse lumbar instability model, MA also improved the tissue disorder and degradation of the intervertebral disc, reduced the loss of proteoglycan and glycosaminoglycan, and inhibited intervertebral disc inflammation, indicating that MA has a protective effect on the intervertebral disc to intervertebral disc in mice.

CONCLUSIONS

Our results suggest that MA slowed IDD development through the PI3K/AKT/NF-κB signaling pathway and NLRP3 inflammasome-mediated pyroptosis, indicating that MA appeared to be a viable medication for IDD treatment.

Hypoxia-Inducible Factor-1α Protects Against Intervertebral Disc Degeneration Through Antagonizing Mitochondrial Oxidative Stress

Intervertebral disc degeneration (IVDD) demonstrates a gradually increased incidence and has developed into a major health problem worldwide. The nucleus pulposus is characterized by the hypoxic and avascular environment, in which hypoxia-inducible factor-1α (HIF-1α) has an important role through its participation in extracellular matrix synthesis, energy metabolism, cellular adaptation to stresses and genesis. In this study, the effects of HIF-1α on mouse primary nucleus pulposus cells (MNPCs) exposed to TNF-α were observed, the potential mechanism was explored and a rabbit IVDD model was established to verify the protective role of HIF-1α on IVDD. In vitro results demonstrated that HIF-1α could attenuate the inflammation, apoptosis and mitochondrial dysfunction induced by TNF-α in MNPCs; promote cellular anabolism; and inhibit cellular catabolism. In vivo results demonstrated that after establishment of IVDD model in rabbit, disc height and IVD extracellular matrix were decreased in a time-dependent manner, MRI analysis showed a tendency for decreased T2 values in a time-dependent manner and supplementation of HIF-1α improved histological and imaginative IVDD while downregulation of HIF-1α exacerbated this degeneration. In summary, HIF-1α protected against IVDD, possibly through reducing ROS production in the mitochondria and consequent inhibition of inflammation, metabolism disorders and apoptosis of MNPCs, which provided a potential therapeutic instrument for the treatment of IVDD diseases.

Netrin-1 mediates nerve innervation and angiogenesis leading to discogenic pain

Objective

Discogenic low back pain (LBP) is associated with nociceptive nerve fibers that grow into degenerated intervertebral discs (IVD) but the etiopathogenesis of disease is not fully understood. The purpose of this study was to clarify the role of Netrin-1 in causing discogenic LBP.

Methods

The level of nociceptive nerve innervation was examined in disc degenerative patients and rat needle-punctured models by immunohistochemistry. Nucleus pulposus (NP) cells were isolated from IVD tissues of rats and induced degeneration by interleukin-1β (IL-1β) or tumor necrosis factor α (TNFα). The candidate genes related to neuron outgrowth and migration were selected by Next-generation sequencing (NGS). CRISPR/Cas9 was used to knockdown Netrin-1 in NP cells. The impact of Netrin-1 on nerve innervation were evaluated with P2X2、NF200 staining and microfluidics assay. Meanwhile the CD31 staining and transwell assay were used to evaluate the impact of Netrin-1 in angiogenesis. The proteins and RNA extracted from NP cells related to catabolism and anabolism were examined by western blot assay and RT-qPCR experiment. ChIP and luciferase experiments were used to assess the intracellular transcriptional regulation of Netrin-1. Further, a needle-punctured rat model followed by histomorphometry and immunofluorescence histochemistry was used to explore the potential effect of Netrin-1 on LBP in vivo.

Results

The level of nerve innervation was increased in severe disc degenerative patients while the expression of Netrin-1 was upregulated. The supernatants of NP cells stimulated with IL-1β or TNFα containing more Netrin-1 could promote axon growth and vascular endothelial cells migration. Knocking down Netrin-1 or overexpressing transcription factor TCF3 as a negative regulator of Netrin-1 attenuated this effect. The needle-punctured rat model brought significant spinal hypersensitivity, nerve innervation and angiogenesis, nevertheless knocking down Netrin-1 effectively prevented disc degeneration-induced adverse impacts.

Conclusion

Discogenic LBP was induced by Netrin-1, which mediated nerve innervation and angiogenesis in disc degeneration. Knocking down Netrin-1 by CRISPR/Cas9 or negatively regulating Netrin1 by transcription factor TCF3 could alleviate spinal hypersensitivity.

The translational potential of this article

This study on Netrin-1 could provide a new target and theoretical basis for the prevention and treatment for discogenic back pain.

Discogenic Low Back Pain: Anatomy, Pathophysiology and Treatments of Intervertebral Disc Degeneration

Intervertebral disc (IVD) degeneration is a major contributing factor for discogenic low back pain (LBP), causing a significant global disability. The IVD consists of an inner core proteoglycan-rich nucleus pulposus (NP) and outer lamellae collagen-rich annulus fibrosus (AF) and is confined by a cartilage end plate (CEP), providing structural support and shock absorption against mechanical loads. Changes to degenerative cascades in the IVD cause dysfunction and instability in the lumbar spine. Various treatments include pharmacological, rehabilitation or surgical interventions that aim to relieve pain; however, these modalities do not halt the pathologic events of disc degeneration or promote tissue regeneration. Loss of stem and progenitor markers, imbalance of the extracellular matrix (ECM), increase of inflammation, sensory hyperinnervation and vascularization, and associated signaling pathways have been identified as the onset and progression of disc degeneration. To better understand the pain originating from IVD, our review focuses on the anatomy of IVD and the pathophysiology of disc degeneration that contribute to the development of discogenic pain. We highlight the key mechanisms and associated signaling pathways underlying disc degeneration causing discogenic back pain, current clinical treatments, clinical perspective and directions of future therapies. Our review comprehensively provides a better understanding of healthy IVD and degenerative events of the IVD associated with discogenic pain, which helps to model painful disc degeneration as a therapeutic platform and to identify signaling pathways as therapeutic targets for the future treatment of discogenic pain.

The regulatory role and therapeutic application of pyroptosis in musculoskeletal diseases

Pyroptosis is a controlled form of inflammatory cell death characterized by inflammasome activation, pore formation, and cell lysis. According to different caspases, pyroptosis can be divided into canonical, non-canonical, and other pathways. The role of pyroptosis in disease development has been paid more attention in recent years. The trigger factors of pyroptosis are often related to oxidative stress and proinflammatory substances, which coincide with the pathological mechanism of some diseases. Pyroptosis directly leads to cell lysis and death, and the release of cytosolic components and proinflammatory cytokines affects cell activity and amplifies the inflammatory response. All the above are involved in a series of basic pathological processes, such as matrix degradation, fibrosis, and angiogenesis. Since these pathological changes are also common in musculoskeletal diseases (MSDs), emerging studies have focused on the correlations between pyroptosis and MSDs in recent years. In this review, we first summarized the molecular mechanism of pyroptosis and extensively discussed the differences and crosstalk between pyroptosis, apoptosis, and necrosis. Next, we elaborated on the role of pyroptosis in some MSDs, including osteoarthritis, rheumatoid arthritis, osteoporosis, gout arthritis, ankylosing spondylitis, intervertebral disc degeneration, and several muscle disorders. The regulation of pyroptosis could offer potential therapeutic targets in MSDs treatment. Herein, the existing drugs and therapeutic strategies that directly or indirectly target pyroptosis pathway components have been discussed in order to shed light on the novel treatment for MSDs.

Role of Pyroptosis in Intervertebral Disc Degeneration and Its Therapeutic Implications

Intervertebral disc degeneration (IDD), a progressive and multifactorial pathological process, is predominantly associated with low back pain and permanent disability. Pyroptosis is a type of lytic programmed cell death triggered by the activation of inflammasomes and caspases. Unlike apoptosis, pyroptosis is characterized by the rupture of the plasma membrane and the release of inflammatory mediators, accelerating the destruction of the extracellular matrix (ECM). Recent studies have shown that pyrin domain-containing 3 (NLRP3) inflammasome-mediated pyroptosis in nucleus pulposus (NP) cells is activated in the progression of IDD. Furthermore, targeting pyroptosis in IDD demonstrates the excellent capacity of ECM remodeling and its anti-inflammatory properties, suggesting that pyroptosis is involved in the IDD process. In this review, we briefly summarize the molecular mechanism of pyroptosis and the pathogenesis of IDD. We also focus on the role of pyroptosis in the pathological progress of IDD and its targeted therapeutic application.

Neuropeptide Y and receptors are associated with the pyroptosis of nucleus pulposus in aging and degenerative intervertebral discs of rats

The neuropeptide Y(NPY) mediates bone metabolism and the degradation of cartilage in the peripheral nervous system. However, its role in the intervertebral disc degeneration (IDD) is less clear and warrant further study. The process of IDD has always been accompanied by inflammatory response and pyroptosis of nucleus pulposus cells (NPCs). The aim of this study was to investigate the relationship between NPY, Y1R, Y2R and pyroptosis in aging and degenerative discs and the direct effect of NPY on NPCs. First, we have assessed NPY, Y1R, Y2R and the expression of pyroptosis related protein in the immature (6 weeks), mature (16 weeks), aged (54 weeks), and degenerated discs. As part of our studies, we also have evaluated pyroptotic changes in the NPCs, induced by exposure to NPY. Our results suggested that compared with natural aging discs, the degenerative discs showed the high expression of NPY, Y1R and Y2R. Correlation analysis showed that the level of NPY and Y1R in degenerative discs were positively correlated with GSDMD, whereas there was no significant correlation between Y2R and GSDMD. In vitro, NPY treatment stimulated the activation of caspase-1-dependent pyroptosis of NPCs. However, Y1R antagonist inhibited NPY-induced pyroptosis of NPCs. Western blot confirmed that Y1R antagonist decreased the level of cleaved.GSDMD and caspase-1 in NPCs. In conclusion, our results indicated that compared with natural aging discs, the degenerated discs showed the high expression of NPY, Y1R and Y2R. NPY-Y1R involve the IDD development by the regulation of pyroptosis in the NPCs. Regulating the function of NPY may be a promising strategy for IDD treatment.

Celecoxib activates autophagy by inhibiting the mTOR signaling pathway and prevents apoptosis in nucleus pulposus cells

BACKGROUND

Intervertebral disc degeneration results from a variety of etiologies, including inflammation and aging. Degenerated intervertebral discs feature down-regulated extracellular matrix synthesis, resulting in losing their ability to retain water and absorb compression. Celecoxib is a well-known selective cyclooxygenase-2 inhibitor for treating arthritis and relieving pain. Nevertheless, the mechanism of Celecoxib for treating inflammation-related intervertebral disc degeneration has not yet been clarified.

METHOD

Protein synthesis was analyzed by western blot. Fluorescent probes DCFH-DA and MitoSox Red detected reactive oxygen species and were measured by flow cytometry. The activity of the kinase pathway was evaluated by protein phosphorylation. Autophagy was monitored by mRFP-GFP-LC3 transfection and LC3 analysis. Mitochondrial apoptotic proteins were analyzed by western blot and cell membrane integrity was measured by flow cytometry. The autophagic gene was silenced by siRNA.

RESULTS

In this study, interleukin-1β stimulation reduced the synthesis of aggrecan, type I and II collagen and caused excessive production of reactive oxygen species. We looked for a therapeutic window of Celecoxib for nucleus pulposus cells to regain extracellular matrix synthesis and reduce oxidative stress. To look into nucleus pulposus cells in response to stimuli, enhancement of autophagy was achieved by Celecoxib, confirmed by mRFP-GFP-LC3 transfection and LC3 analysis. The mammalian target of rapamycin and a panel of downstream proteins responded to Celecoxib and propelled autophagy machinery to stabilize homeostasis. Ultimately, inhibition of autophagy by silencing autophagy protein 5 disrupted the protective effects of Celecoxib, culminating in apoptosis.

CONCLUSION

In summary, we have demonstrated a new use for the old drug Celecoxib that treats intervertebral disc degeneration by enhancing autophagy in nucleus pulposus cells and opening a door for treating other degenerative diseases.

TNF-α Inhibitors from Natural Compounds: An Overview, CADD Approaches, and their Exploration for Anti-inflammatory Agents

Inflammation is a natural process that occurs in the organism in response to harmful external agents. Despite being considered beneficial, exaggerated cases can cause severe problems for the body. The main inflammatory manifestations are pain, increased temperature, edema, decreased mobility, and quality of life for affected individuals. Diseases such as arthritis, cancer, allergies, infections, arteriosclerosis, neurodegenerative diseases, and metabolic problems are mainly characterized by an exaggerated inflammatory response. Inflammation is related to two categories of substances: pro- and anti-inflammatory mediators. Among the pro-inflammatory mediators is Tumor Necrosis Factor-α (TNF-α). It is associated with immune diseases, cancer, and psychiatric disorders which increase its excretion. Thus, it becomes a target widely used in discovering new antiinflammatory drugs. In this context, secondary metabolites biosynthesized by plants have been used for thousands of years and continue to be one of the primary sources of new drug scaffolds against inflammatory diseases. To decrease costs related to the drug discovery process, Computer-Aided Drug Design (CADD) techniques are broadly explored to increase the chances of success. In this review, the main natural compounds derived from alkaloids, flavonoids, terpene, and polyphenols as promising TNF-α inhibitors will be discussed. Finally, we applied a molecular modeling protocol involving all compounds described here, suggesting that their interactions with Tyr⁵⁹, Tyr¹¹⁹, Tyr¹⁵¹, Leu⁵⁷, and Gly¹²¹ residues are essential for the activity. Such findings can be useful for research groups worldwide to design new anti-inflammatory TNF-α inhibitors.

Inhibition of Microglial NLRP3 with MCC950 Attenuates Microglial Morphology and NLRP3/Caspase-1/IL-1β Signaling In Stress-induced Mice

Major depressive disorder is characterized by the deficiencies of monoamine neurotransmitters, neurotrophic factors and persistent neuroinflammation. Microglial activation has been associated with neuroinflammation-related mental diseases, accompanied by NLR family pyrin domain containing 3 (NLRP3) inflammasome. Here, we investigated the effect of NLRP3 inhibition by its small molecular inhibitor MCC950 on inflammatory activity and depressive-like mice induced by chronic unpredictable mild stress (CUMS), followed by the behavioral tests including sucrose preference test and forced swimming test. NLRP3/caspase-1/IL-1β signaling and microglial morphology in the prefrontal cortex were measured. The results showed that CUMS caused a decrease in sucrose preference and an increase in immobility time, which were reversed by NLRP3 inhibitor MCC950. In addition, NLRP3 inhibition decreased the number of microglia and changed the activated state of microglia to a resting state by morphology 3D reconstruction. Moreover, NLRP3 inhibition inactivated NLRP3/caspase-1/IL-1β signaling in the prefrontal cortex. The results from immunofluorescence demonstrated that NLRP3 and IL-1β expression was decreased in microglia in response to MCC950 treatment. Accordingly, proinflammatory cytokines were also decreased by NLRP3 inhibition. In conclusion, this study demonstrates that microglial NLRP3 inhibition prevents stress-induced neuroinflammation in the prefrontal cortex and suggests that microglial NLRP3 could be one of the potential therapeutic targets for depression treatment.

Celecoxib activates autophagy by inhibiting the mTOR signaling pathway and prevents apoptosis in nucleus pulposus cells

BACKGROUND

Intervertebral disc degeneration results from a variety of etiologies, including inflammation and aging. Degenerated intervertebral discs feature down-regulated extracellular matrix synthesis, resulting in losing their ability to retain water and absorb compression. Celecoxib is a well-known selective cyclooxygenase-2 inhibitor for treating arthritis and relieving pain. Nevertheless, the mechanism of Celecoxib for treating inflammation-related intervertebral disc degeneration has not yet been clarified.

METHOD

Protein synthesis was analyzed by western blot. Fluorescent probes DCFH-DA and MitoSox Red detected reactive oxygen species and were measured by flow cytometry. The activity of the kinase pathway was evaluated by protein phosphorylation. Autophagy was monitored by mRFP-GFP-LC3 transfection and LC3 analysis. Mitochondrial apoptotic proteins were analyzed by western blot and cell membrane integrity was measured by flow cytometry. The autophagic gene was silenced by siRNA.

RESULTS

In this study, interleukin-1β stimulation reduced the synthesis of aggrecan, type I and II collagen and caused excessive production of reactive oxygen species. We looked for a therapeutic window of Celecoxib for nucleus pulposus cells to regain extracellular matrix synthesis and reduce oxidative stress. To look into nucleus pulposus cells in response to stimuli, enhancement of autophagy was achieved by Celecoxib, confirmed by mRFP-GFP-LC3 transfection and LC3 analysis. The mammalian target of rapamycin and a panel of downstream proteins responded to Celecoxib and propelled autophagy machinery to stabilize homeostasis. Ultimately, inhibition of autophagy by silencing autophagy protein 5 disrupted the protective effects of Celecoxib, culminating in apoptosis.

CONCLUSION

In summary, we have demonstrated a new use for the old drug Celecoxib that treats intervertebral disc degeneration by enhancing autophagy in nucleus pulposus cells and opening a door for treating other degenerative diseases.

Pseudolycorine chloride ameliorates Th17 cell-mediated central nervous system autoimmunity by restraining myeloid-derived suppressor cell expansion

CONTEXT

The alkaloids of Narcissus tazetta L. var. Chinensis Roem (Amaryllidaceae) have antitumor and antiviral activities. However, the immunopharmacological effects of one of its constituents, pseudolycorine chloride (PLY), have not been reported yet.

OBJECTIVE

We evaluated the effect of PLY on myeloid-derived suppressor cells (MDSCs) expansion and differentiation into monocyte-like MDSCs (M-MDSCs) and examined whether PLY alleviates Th17 cell-mediated experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS).

MATERIALS AND METHODS

In vitro, MDSCs were treated with PLY (0.67, 2 and 6 μM) or solcitinib (10 μM, positive control) for 48 or 96 h, and their proliferation, expansion, and differentiation into M-MDSCs were examined by flow cytometry. Myelin oligodendrocyte glycoprotein (MOG_35-55) was used to induce EAE in female C57BL/6 mice, and the mice were treated with 40 mg/kg/d PLY or 1 mg/kg/d FK-506 (tacrolimus, positive control) for 21 days. Inflammatory infiltration, spinal cord demyelination, and MDSCs and Th17 cells infiltration into the spinal cord were examined using haematoxylin and eosin staining, Luxol fast blue staining, and immunofluorescence, respectively.

RESULTS

In vitro, PLY (IC50/24 h = 6.18 μM) significantly inhibited IL-6 and GM-CSF-induced MDSCs proliferation, expansion and differentiation into M-MDSCs at all concentrations used. However, these concentrations did not show cytotoxicity. In mice, PLY (40 mg/kg) treatment alleviated EAE and inhibited inflammatory infiltration, demyelination, and MDSCs and Th17 cells infiltration into the spinal cord.

DISCUSSION AND CONCLUSIONS

PLY may be an excellent candidate for the treatment of MS and other autoimmune diseases.

Long non-coding RNAs LINC00689 inhibits the apoptosis of human nucleus pulposus cells via miR-3127-5p/ATG7 axis-mediated autophagy

This study aimed to explore the effects of long non-coding RNAs LINC00689 (LINC00689) in human nucleus pulposus cells (NPCs). NPCs were isolated and their morphology was observed. The proliferation and apoptosis of NPCs, and the levels of LINC00689, miR-3127-5p, Bax, Bcl-2, Cleaved caspase-3, ATG5, ATG7, p62, and LC3Ⅱ/LC3I were detected. Interrelations of LINC00689, miR-3127-5p, and ATG7 were analyzed. LINC00689 was down-regulated yet miR-3127-5p was up-regulated in NPCs. LINC00689 could competitively bind with miR-3127-5p, and ATG7 was targeted by miR-3127-5p in NPCs. Overexpressed LINC00689 promoted proliferation yet inhibited apoptosis of NPCs, whereas LINC00689 silencing did the opposite. Overexpressed LINC00689 raised ATG7 level and LC3Ⅱ/LC3I value yet reduced that of p62 level, but the depletion of LINC00689 did the contrary. ATG7 silencing abolished the effects of overexpressed LINC00689 in NPCs, and likewise, up-regulation of miR-3127-5p overturned the effects of overexpressed LINC00689 in NPCs. Collectively, the up-regulation of LINC00689 inhibits the apoptosis of NPCs via miR-3127-5p/ATG7 axis-mediated autophagy.

Genomic G-quadruplex folding triggers a cytokine-mediated inflammatory feedback loop to aggravate inflammatory diseases

DNA G-quadruplex is a non-canonical secondary structure that could epigenetically regulate gene expression. To investigate the regulating role of G-quadruplex, we devised an integrating method to perform the algorithm profiling and genome-wide analysis for the dynamic change of genomic G-quadruplex and RNA profiles in rat nucleus pulposus cells by inducing G-quadruplex folding with multiple stabilizers. A group of genes potentially regulated by G-quadruplex and involved in the inflammation process has been identified. We found that G-quadruplex folding triggers inflammation response by upregulating inflammatory cytokines, which could promote G-quadruplex folding in a manner of positive feedback loop. Moreover, we confirmed that G-quadruplex is a marker indicating elevated inflammatory status and G-quadruplex folding facilitates the development of inflammatory diseases using in vivo intervertebral disc degeneration models. The crosstalk between G-quadruplex and inflammatory cytokines plays a vital role in regulating inflammation-derived diseases, which may provide new insights into the blocking target.

Effect of intervertebral disc degeneration on the stomatognathic system function in adults

OBJECTIVE

To analyze the electromyographic activity (EMG) and thermographic patterns of the masseter and temporalis muscles and pressure of the orofacial tissues in individuals with intervertebral disc degeneration (IDD).

METHODS

This study had two distinct groups: with IDD (n = 16) and controls (n = 16). EMG at rest, protrusion, right and left laterality, and maximum voluntary contraction were evaluated. Tongue, orbicularis oris, and buccinator muscles pressures were measured by Iowa Oral Performance Instrument. The thermographic patterns were analyzed using infrared thermography.

RESULTS

Comparisons between groups showed significant differences regarding at rest [right (p = 0.05) and left (p = 0.05) masseter and right temporal (p = 0.05)], orofacial tissue pressure [tongue (p = 0.001), orbicularis oris (p = 0.01), and buccinator (p = 0.0001)], but no significant differences for the thermographic patterns.

CONCLUSION

IDD modifies the functionality of the craniomandibular complex, influencing the performance of the stomatognathic system.

Eupatilin attenuates the senescence of nucleus pulposus cells and mitigates intervertebral disc degeneration via inhibition of the MAPK/NF-κB signaling pathway

Intervertebral disc degeneration (IDD) is the main cause of low back pain. An increasing number of studies have suggested that inflammatory response or the senescence of nucleus pulposus (NP) cells is strongly associated with the progress of IDD. Eupatilin, the main flavonoid extracted from Artemisia, was reported to be associated with the inhibition of the intracellular inflammatory response and the senescence of cells. However, the relationship between eupatilin and IDD is still unknown. In this study, we explored the role of eupatilin in tumor necrosis factor-α (TNF-α)-induced activation of inflammatory signaling pathways and NP cell senescence, in the anabolism and catabolism of NP cell extracellular matrix (ECM) and in the effect of the puncture-induced model of caudal IDD in the rat. In vitro, eupatilin significantly inhibited TNF-α-induced ECM degradation, downregulated the expression of related markers of NP cells (MMP3, MMP9, and MMP13), and upregulated the expression of SOX9 and COL2A1. Furthermore, eupatilin reduced TNF-α-induced cell senescence by inhibiting the expression of the senescence of NP cell-related markers (p21 and p53). Mechanistically, ECM degradation and cell senescence were reduced by eupatilin, which inhibited the activation of MAPK/NF-κB signaling pathways. Consistent with the in vitro data, eupatilin administration ameliorated the puncture-induced model of caudal IDD in the rat. In conclusion, eupatilin can inhibit the inflammatory response and the senescence of NP cells, which may be a novel treatment strategy for IDD.

Correlation between serum angiotensin-converting enzyme (ACE) levels and intervertebral disc degeneration

Studies have shown that the renin-angiotensin system (RAS) might play an essential role in intervertebral disc degeneration (IDD). The study aimed to investigate the relationship between serum angiotensin-converting enzyme (ACE) concentration and IDD and its predictive value for severe disc degeneration. 245 patients who came to our hospital for low back pain were recruited, and blood samples were collected for routine examination. Descriptive data and demographic parameters were collected. The cumulative grade 1 was calculated by summing up the Pfirrmann grade of all lumbar discs. ACE concentration grouping was determined via tertile split. Correlation analysis and multivariable linear regression analysis were performed to determine the relationship between ACE and IDD. The receiver's degree of disc degeneration (ROC) curve determined the ACE's predictive value. Results indicated that there was no significant difference in demographic parameters among groups. Correlation analysis and multivariate linear analysis showed that ACE was an independent risk factor for IDD. The cumulative grade 1 increased significantly with the increase in ACE concentration, which was consistent with the correlation analysis. Average Pfirrmann grade &lt; 4 indicates mild to moderate degeneration, and grade ≥ 4 indicates severe degeneration in terms of an individual disc. From L1/2 to L5/S1, the mean plasma ACE concentration was significantly higher in the severe degeneration group than in the mild to moderate degeneration group. According to the ROC curve, the cut-off value of ACE levels was 22.5. patients with ACE &gt; 22.5 had severe degeneration. The sensitivity and specificity were 0.762 and 0.521, respectively.

Proanthocyanidins inhibit the apoptosis and aging of nucleus pulposus cells through the PI3K/Akt pathway delaying intervertebral disc degeneration

BACKGROUND

Low back pain is a common symptom of intervertebral disc degeneration (IDD), which seriously affects the quality of life of patients. The abnormal apoptosis and senescence of nucleus pulposus (NP) cells play important roles in the pathogenesis of IDD. Proanthocyanidins (PACs) are polyphenolic compounds with anti-apoptosis and anti-aging effects. However, their functions in NP cells are not yet clear. Therefore, this study was performed to explore the effects of PACs on NP cell apoptosis and aging and the underlying mechanisms of action.

METHODS

Cell viability was evaluated by cell counting kit-8 (CCK-8) assay. The apoptosis rate was determined TUNEL assays. Levels of apoptosis-associated molecules (Bcl-2, Bax, C-caspase-3 and Caspase-9) were evaluated via western blot. The senescence was observed through SA-β-gal staining and western blotting analysis was performed to observe the expression of senescence-related molecules (p-P53, P53, P21 and P16).

RESULTS

Pretreatment with PACs exhibited protective effects against IL-1β-induced NP cell apoptosis including apoptosis rate, expressions of proapoptosis and antiapoptosis related genes and protein. PACs could also alleviate the increase of p-p53, P21, and P16 in IL-1β-treated NP cells. SA-β-gal staining showed that IL-1β-induced senescence of NP cells was prevented by PACs pertreatment. In addition, PACs activated PI3K/Akt pathway in IL-1β-stimulated NP cells. However, these protected effects were inhibited after LY294002 treatment.

CONCLUSION

The results of the present study showed that PACs inhibit IL-1β-induced apoptosis and aging of NP cells by activating the PI3K/Akt pathway, and suggested that PACs have therapeutic potential for IDD.

Degenerative Disc Disease of the Spine: From Anatomy to Pathophysiology and Radiological Appearance, with Morphological and Functional Considerations

Degenerative disc disease is a common manifestation in routine imaging of the spine; this finding is partly attributable to physiological aging and partly to a pathological condition, and sometimes this distinction is simply not clear. In this review, we start focusing on disc anatomy and pathophysiology and try to correlate them with radiological aspects. Furthermore, there is a special focus on degenerative disc disease terminology, and, finally, some considerations regarding disc morphology and its specific function, as well as the way in which these aspects change in degenerative disease. Radiologists, clinicians and spine surgeons should be familiar with these aspects since they have an impact on everyday clinical practice.

Effect of regulating macrophage polarization phenotype on intervertebral disc degeneration

Background

Macrophages are the only inflammatory cells that can penetrate the closed nucleus pulposus and their polarization plays an important role in intervertebral disc degeneration (IVDD). This paper attempted to investigate the pathogenesis of IVDD by altering the polarization state of macrophages.

Methods

Macrophage RAW264.7 cells were induced by interferonγ (IFN‐γ) and lipopolysaccharide (LPS). The polarization of RAW264.7 cells was estimated by western blot and immunofluorescence. The expressions of inflammatory factors were detected by ELISA. Subsequently, RAW264.7 cells were treated with different concentrations of minocycline (Mino) and sinomenine (Sino), followed by the assessment of cell viability with cell counting kit‐8 kit. Then, RAW264.7 cell culture medium was collected for the culture of human nucleus pulposus cells (NPCs). Toluidine blue staining and type II collagen staining were applied to assay the level of type II collagen. The cell apoptosis, oxidative stress, and nitric oxide (NO) level were appraised by TUNEL, oxidative stress kits and NO kit, respectively. Western blot was employed to test the levels of apoptosis‐ and oxidative stress‐related proteins.

Results

IFN‐γ and LPS could induce M1 polarization of RAW264.7 cells. Mino and Sino could reduce the polarization of RAW264.7 cells toward M1. M1‐polarized medium inhibited LPS‐induced activity, inflammation, and damage of NPCs, which were enhanced by Mino and Sino in medium.

Conclusion

M1 polarization of macrophages promoted LPS‐induced inflammation and damage of NPCs.

Pharmacological Effects of Resveratrol in Intervertebral Disc Degeneration: A Literature Review

Intervertebral disc degeneration (IDD) is a high incidence disease of musculoskeletal system that often leads to stenosis, instability, pain and even deformity of the spinal segments. IDD is an important cause of discogenic lower back pain and often leads to large economic burden to families and society. Currently, the treatment of IDD is aimed at alleviating symptoms rather than blocking or reversing pathological progression of the damaged intervertebral disc. Resveratrol (RSV) is a polyphenol phytoalexin first extracted from the Veratrum grandiflflorum O. Loes and can be found in various plants and red wine. Owing to the in-depth study of pharmacological mechanisms, the therapeutic potential of RSV in various diseases such as osteoarthritis, neurodegenerative diseases, cardiovascular diseases and diabetes have attracted the attention of many researchers. RSV has anti-apoptotic, anti-senescent, anti-inflammatory, anti-oxidative, and anabolic activities, which can prevent further degeneration of intervertebral disc cells and enhance their regeneration. With high safety and various biological functions, RSV might be a promising candidate for the treatment of IDD. This review summarizes the biological functions of RSV in the treatment of IDD and to facilitate further research.

Autologous cultured adipose derived mesenchymal stem cells combined with hyaluronic acid hydrogel in the treatment of discogenic low back pain: a study protocol for a phase II randomised controlled trial

INTRODUCTION

Discogenic low back pain (DLBP) is a common disease, and its occurrence is closely related to intervertebral disc (IVD) degeneration. At present, none of the traditional treatment methods can repair the degenerated IVD. The emergence of stem cell therapy makes it possible to repair and regenerate IVD tissue, among which adipose derived mesenchymal stem cells (ADMSCs) transplantation therapy has become a hot spot of current research. Therefore, this trial aimed to investigate the safety and efficacy of using autologous cultured ADMSCs combined with hyaluronic acid (HA) hydrogel in the treatment of DLBP.

METHODS AND ANALYSIS

This study is a randomised, dose-escalation, placebo-controlled, double-blind, single-centre, phase II clinical trial to evaluate the efficacy and safety of autologous cultured ADMSCs combined with HA hydrogel in the treatment of patients with DLBP. The 100 eligible patients will be randomly divided into three experimental groups with different doses and one placebo control group in a ratio of 1:1:1:1. All patients will undergo liposuction to obtain ADMSCs, followed by autologous cultured ADMSC mixtures or placebo transplantation after 3 weeks. The patients will be followed up to 24 months after the transplant. The primary end point of this trial is the Visual Analogue Scale. Secondary end points include the Oswestry Disability Index, Japanese Orthopaedic Association Scores, the Mos 36-item short form, the Modic classification, Pfirrmann grade, height and segment range of motion of the IVD, vital signs (temperature, pulse, respiration, blood pressure), blood routine, liver and kidney function, immunological examination, urinalysis and treatment emergent adverse events.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Ethics Committee of the First Affiliated Hospital of Dalian Medical University and registered in the Chinese Clinical Trial Registry. Dissemination of the results will be presented at a conference and in peer-reviewed publications.

TRIAL REGISTRATION NUMBER

ChiCTR2200058291.

Pyroptosis and Intervertebral Disc Degeneration: Mechanistic Insights and Therapeutic Implications

Low back pain (LBP) is a common problem worldwide, resulting in great patient suffering and great challenges for the social health system. Intervertebral disc (IVD) degeneration (IVDD) is widely acknowledged as one of the key causes of LBP. Accumulating evidence suggests that aberrant pyroptosis of IVD cells is involved in the pathogenesis of IVDD progression, however, the comprehensive roles of pyroptosis in IVDD have not been fully established, leaving attempts to treat IVDD with anti-pyroptosis approaches questionable. In this review, we summarize the characteristics of pyroptosis and emphasize the effects of IVD cell pyroptosis on the pathological progression of IVDD, including secretion of cytokines, nucleus pulposus cell apoptosis and autophagy, accelerated extracellular matrix degradation, annulus fibrosus rupture, cartilage endplate calcification, vascularization, sensory and sympathetic fiber neoinnervation, and infiltrating lymphatic vessels. Finally, we discuss several interventions used to treat IVDD by targeting pyroptosis. This review provides novel insights into the crucial role of IVD cell pyroptosis in IVDD pathogenesis, and could be informative for developing novel therapeutic approaches for IVDD and LBP.

1,8-Cineole inhibits biofilm formation and bacterial pathogenicity by suppressing luxS gene expression in Escherichia coli

In recent years, with frequent reports of multi-drug resistant strains, bacteria antibiotic resistance has become an increasingly serious health problem worldwide. One of the most promising ways for combating bacterial infections and antibiotic resistance is development of quorum-sensing (QS) interfering drugs. In this study, the results show that 1,8-cineole inhibited the expression of QS as well as the virulence genes in Escherichia coli O101 (E. coli O101) with a 65% inhibition rate against luxS gene. Therefore, we hypothesized that 1,8-cineole may inhibit the biofilm formation and reduce the pathogenicity of E. coli O101 by inhibiting the expression of luxS gene. To confirm our hypotheses, a luxS gene deleted E. coli O101 was constructed. The results show that the biofilm formation, motility, structure and pathogenicity of E. coli O101 were significantly inhibited following deletion of the luxS gene. In addition, the transcript levels of QS and virulence genes of E. coli O101 were also significantly down-regulated. Interestingly, 1,8-cineole no longer had a significant inhibitory effect on the related phenotype and gene expression of E. coli O101 without luxS gene. In conclusion, the results show that 1,8-cineole can affect bacterial biofilm formation and pathogenicity by suppressing the expression of luxS gene in E. coli O101, which could provide a new perspective for dealing with the biofilm problem of pathogenic bacteria.

Engineered Human Intervertebral Disc Model Inducing Degenerative Microglial Proinflammation

Degeneration of the intervertebral disc (IVD) is a major contributor to low back pain (LBP). IVD degeneration is characterized by abnormal production of inflammatory cytokines secreted by IVD cells. Although the underlying molecular mechanisms of LBP have not been elucidated, increasing evidence suggests that LBP is associated particularly with microglia in IVD tissues and the peridiscal space, aggravating the cascade of degenerative events. In this study, we implemented our microfluidic chemotaxis platform to investigate microglial inflammation in response to our reconstituted degenerative IVD models. The IVD models were constructed by stimulating human nucleus pulposus (NP) cells with interleukin-1β and producing interleukin-6 (129.93 folds), interleukin-8 (18.31 folds), C-C motif chemokine ligand-2 (CCL-2) (6.12 folds), and CCL-5 (5.68 folds). We measured microglial chemotaxis (p < 0.05) toward the conditioned media of the IVD models. In addition, we observed considerable activation of neurodegenerative and deactivation of protective microglia via upregulated expression of CD11b (p < 0.001) and down-regulation of CD206 protein (p < 0.001) by soluble factors from IVD models. This, in turn, enhances the inflammatory milieu in IVD tissues, causing matrix degradation and cellular damage. Our findings indicate that degenerative IVD may induce degenerative microglial proinflammation, leading to LBP development.

One-step fabrication of lidocaine/CalliSpheres® composites for painless transcatheter arterial embolization

BACKGROUND

Transcatheter arterial embolization (TAE) is one of the first-line treatments for advanced hepatocellular cancer. The pain caused by TAE is a stark complication, which remains to be prevented by biomedical engineering methods.

METHODS

Herein, a commercial embolic agent CalliSpheres^® bead (CB) was functionally modified with lidocaine (Lid) using an electrostatic self-assembly technique. The products were coded as CB/Lid-n (n = 0, 5, 10, corresponding to the relative content of Lid). The chemical compositions, morphology, drug-loading, and drug-releasing ability of CB/Lid-n were comprehensively investigated. The biocompatibility was determined by hemolysis assay, live/dead cell staining assay, CCK8 assay, immunofluorescence (IHC) staining assay and quantitative real-time PCR. The thermal withdrawal latency (TWL) and edema ratio (ER) were performed to evaluate the analgesia of CB/Lid-n using a plantar inflammation model. A series of histological staining, including immunohistochemistry (IL-6, IL-10, TGF-β and Navi1.7) and TUNEL were conducted to reveal the underlying mechanism of anti-tumor effect of CB/Lid-n on a VX2-tumor bearing model.

RESULTS

Lid was successfully loaded onto the surface of CalliSpheres^® bead, and the average diameter of CalliSpheres^® bead increased along with the dosage of Lid. CB/Lid-n exhibited desirable drug-loading ratio, drug-embedding ratio, and sustained drug-release capability. CB/Lid-n had mild toxicity towards L929 cells, while triggered no obvious hemolysis. Furthermore, CB/Lid-n could improve the carrageenan-induced inflammation response micro-environment in vivo and in vitro. We found that CB/Lid-10 could selectively kill tumor by blocking blood supply, inhibiting cell proliferation, and promoting cell apoptosis. CB/Lid-10 could also release Lid to relieve post-operative pain, mainly by remodeling the harsh inflammation micro-environment (IME).

CONCLUSIONS

In summary, CB/Lid-10 has relatively good biocompatibility and bioactivity, and it can serve as a promising candidate for painless transcatheter arterial embolization.

Innovative immune mechanisms and antioxidative therapies of intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is the basic pathological process of many degenerative diseases of the spine, characterized by series of symptoms, among which low back pain (LBP) is the most common symptom that patients suffer a lot, which not only makes patients and individual families bear a huge pain and psychological burden, but also consumes a lot of medical resources. IDD is usually thought to be relevant with various factors such as genetic predisposition, trauma and aging, and IDD progression is tightly relevant with structural and functional alterations. IDD processes are caused by series of pathological processes, including oxidative stress, matrix decomposition, inflammatory reaction, apoptosis, abnormal proliferation, cell senescence, autophagy as well as sepsis process, among which the oxidative stress and inflammatory response are considered as key link in IDD. The production and clearance of ROS are tightly connected with oxidative stress, which would further simulate various signaling pathways. The phenotype of disc cells could change from matrix anabolism-to matrix catabolism- and proinflammatory-phenotype during IDD. Recent decades, with the relevant reports about oxidative stress and inflammatory response in IDD increasing gradually, the mechanisms researches have attracted much more attention. Consequently, this study focused on the indispensable roles of the oxidative stress and inflammatory response (especially macrophages and cytokines) to illustrate the origin, development, and deterioration of IDD, aiming to provide novel insights in the molecular mechanisms as well as significant clinical values for IDD.

Engeletin Alleviates the Inflammation and Apoptosis in Intervertebral Disc Degeneration via Inhibiting the NF-κB and MAPK Pathways

Purpose

Low back pain (LBP) induced by intervertebral disc degeneration (IDD) brings progressively painful status and impairs the normal daily living. Engeletin is a plant-derived medicine with anti-inflammation and antioxidant functions. Therefore, we aim to confirm its protective effects against the intervertebral disc degeneration in vivo and in vitro.

Methods

The cytotoxicity of engeletin was validated by CCK-8 tests. Using the TNF-α to simulate the inflammation status in vitro, the expression of inflammatory mediators and MMP families were determined by qPCR, Western blotting and confocal microscopy. Cell apoptosis was analyzed by flow cytometry and TUNEL assay. The expression of apoptosis-related proteins was tested by Western blotting. The activation of NF-κB and MAPK pathways was evaluated by Western blotting and confocal microscopy. In vivo, percutaneous needle puncture was used to establish the IDD model in rat, and engeletin was administrated via intradiscal injection. The therapeutic effects of engeletin were detected through imaging and histology analysis.

Results

Cell viability tests demonstrated there was little cytotoxicity of engeletin toward NP cells. Pretreatment with engeletin effectively ameliorate the TNF-α-induced up-regulation of inflammatory mediators and MMP families, promoting the anabolism of ECM meanwhile. Cell apoptosis was also attenuated with the addition of engeletin. We found that the activation of MAPK and NF-κB signaling pathways and the nuclear translocation of phosphorylated p65 and p38 were inhibited prominently with the treatment of engeletin which may be the potential molecular mechanism for its anti-inflammation effects. Finally, the IDD induced by percutaneous needle puncture was partially alleviated with the injection of engeletin in vivo.

Conclusion

As a natural compound with little cytotoxicity, engeletin possesses the outstanding anti-inflammation and anti-apoptosis effects in the process of IDD in vitro and in vivo, which may be a promising medicine for the prevention and treatment of IDD-related low back pain.

Intradiscal Autologous Platelet-Rich Plasma Injection for Discogenic Low Back Pain: A Clinical Trial

Background. Platelet-rich plasma (PRP) contains high concentrations of growth factors and cytokines and may promote healing and tissue formation and exert anti-inflammatory effects. PRP has been shown to improve intervertebral disc degeneration in vivo and in vitro. This study is aimed at evaluating the effectiveness of autologous PRP on discogenic low back pain (DLBP) at 48 weeks postinjection in patients who received a single intradiscal injection. Methods. All patients received a single intradiscal injection of PRP in a prospective trial. The pain scores, lumbar function, and adverse events were assessed at 1 week, 4 weeks, 8 weeks, 12 weeks, 24 weeks, and 48 weeks postinjection and compared to the preinjection values (0 weeks). Results. Data were analysed from 31 patients with a 94% follow-up rate. Compared to preinjection, pain and lumbar function were significantly improved, and there were significant differences ( $P<0.05$ ) over the 48-week follow-up. Twenty-two (71%) patients were classified as successes after the intradiscal injection of PRP. One patient received surgery at two weeks postinjection due to intervertebral discitis. Conclusions. Intradiscal injection of PRP can significantly relieve pain sensation and improve lumbar function in patients with DLBP over a 48-week follow-up period. Further randomized controlled clinical trials are needed to assess the effects of this injection therapy.

N6-Methyladenosine-induced miR-143-3p promotes intervertebral disc degeneration by regulating SOX5

Intervertebral disc degeneration is the basic cause of lumbocrural pain, which not only causes pain and but also serious economic burdens on patients. Increasingly more evidence has shown that tumor necrosis factor-α (TNF-α) is involved in the pathological process of intervertebral disc degeneration, but the specific molecular mechanism is still unclear. This study investigated the potential mechanism and function of methyltransferase-like 3 (METTL3)/miR-143-3p/SOX5 regulatory axis in nucleus pulposus cells under the action of TNF-α. Human nucleus pulposus cells were treated with TNF-α to construct an in vitro model of intervertebral disc degeneration. Flow cytometry, quantitative reverse-transcription PCR (RT-qPCR), Western blot (WB) and luciferase assays were used to identify the mechanism of action of miR-143-3p in the course of intervertebral disc degeneration in vitro and the downstream targeted regulatory molecules. The role of miR-143-3p in intervertebral disc degeneration was also validated by in vivo. RT-qPCR, WB, coimmunoprecipitation (Co-IP) and flow cytometry were used to verify the regulatory effect of METTL3 on miR-143-3p maturation. RT-qPCR and WB were adopted to detect differences in METTL3, miR-143-3p and SOX5 expression in human nucleus pulposus tissue. miR-143-3p in nucleus pulposus cells was involved in the regulation of extracellular matrix metabolism and apoptosis after TNF-α stimulation, and intervertebral disc degeneration was relieved by effectively regulating miR-143-3p expression. Subsequent experiments showed that the downstream direct target gene of miR-143-3p was SOX5 and that miR-143-3p negatively regulated the expression of SOX5. In addition, METTL3 promoted miR-143-3p maturation, and METTL3 and miR-143-3p were significantly upregulated in degenerative nucleus pulposus, an effect that was significantly negatively correlated with low SOX5 expression. In conclusion, TNF-α upregulates METTL3, METTL3 promotes miR-143-3p maturation, and miR-143-3p inhibits the transcriptional activity of SOX5 through targeted binding, thereby inducing intervertebral disc degeneration. The inhibition of METTL3 or miR-143-3p expression may be an effective way to treat intervertebral disc degeneration.

Development of a Novel Inflammatory-Associated Gene Signature and Immune Infiltration Patterns in Intervertebral Disc Degeneration

Background. Both inflammatory factors and immune response play important roles in the pathogenesis of intervertebral disc degeneration (IDD). However, a comprehensive analysis of interaction between inflammatory response-associated genes (IRGs) and immune microenvironment in patients with IDD remains lacking. Hence, the current research is aimed at investigating the correlations between IRG signatures and immune cells in the progression of IDD. Methods. The expression profiles (GSE27494 and GSE41883) and IRGs were downloaded from the Gene Expression Omnibus (GEO) database and Molecular Signature Database (MSigDB), respectively. Weighted gene coexpression network analysis (WGCNA) and differential expression analysis were used to identify the pivotal modules and common differentially expressed genes (DEGs) associated with IDD. Subsequently, we retrieved differentially expressed IRGs (DE-IRGs) by intersecting IRGs and DEGs for enrichment analysis. Next, LASSO regression analyses were performed to screen optimal marker genes for IDD prediction. Additionally, we validated differences DE-IRGs between IDD patients and controls in GSE150408. Finally, the infiltration alteration of immune cells was evaluated by the CIBERSORT, and the correlation between diagnostic markers and infiltrating immune cells was analyzed. Results. A total of 10 upregulated differentially expressed inflammatory genes were identified that were obviously related to progression of IDD. Functional analysis results revealed that DE-IRGs were mainly enriched in signaling pathways TNF, IL-17, NOD-like receptor, and NF-kappa B pathway. A five-gene signature that consisted of IL-1β, LIF, LYN, NAMPT, and SLC7A2 was constructed by the LASSO Cox regression. IL1B, LYN, and NAMPT were further validated as optimal candidate genes in the pathophysiology of IDD. In addition, there was a remarkable immune cell infiltration difference between the healthy and IDD groups. The proportions for dendritic cells activated, mast cells activated, and neutrophils in the IDD group were significantly higher than those in the normal group, while the proportion of some cells was lower than that of the normal group, such as T cell CD4 memory resting, NK cells activated, and macrophage M0. Furthermore, correlation analysis indicated IL-1β, LYN, and NAMPT were closely implicated with immune cell infiltration in IDD development. Conclusions. We explored an association between inflammatory response-associated signature and immune infiltration in IDD and validated that IL-1β, LYN, and NAMPT might serve as biomarkers and therapeutic targets for IDD in the future.

Effects of Fluid Shear Stress on Human Intervertebral Disc Nucleus Pulposus Cells Based on Label-Free Quantitative Proteomics

Objective

To explore the possible mechanism of fluid shear stress on human nucleus pulposus cells based on label-free proteomics technology.

Methods

The human nucleus pulposus cell line was purchased and subcultured in vitro. The Flexcell STR-4000 multiflow field cell fluid shear stress loading culture system was used to apply continuous laminar fluid shear stress (12 dyne/cm², 45 mins) to the monolayer adherent cells. Those without mechanical loading were used as the control group, and those subjected to fluid shear loading were used as the experimental group. Differential protein expression was identified using mass spectrometry identification technology, and bioinformatics analysis was performed using Gene Ontology GO (Gene Ontology) and Kyoto Encyclopedia of Genes and Genomes KEGG (Kyoto Encyclopedia of Genes and Genomes).

Results

The proteomics results of the experimental group and the control group showed that the total number of mass spectra was 638653, the number of matched mass spectra was 170110, the total number of identified peptides was 32050, the specific peptide was 30564, and the total number of identified proteins was 4745. Comparing the two groups, 47 proteins were significantly differentially expressed, namely, 25 upregulated proteins and 22 downregulated proteins. Bioinformatics analysis showed that significantly different proteins were mainly manifested in cellular process, biological regulation, metabolic process, binding, catalytic activity, cellular components (cell part), organelle part (organelle part), and other molecular biological functions.

Conclusion

Using proteomics technology to screen human nucleus pulposus cells after fluid shear stress loading, the differential protein expression provides a basis for further exploration of the mechanism of mechanical factors on nucleus pulposus.

Icariin protects vertebral endplate chondrocytes against apoptosis and degeneration via activating Nrf-2/HO-1 pathway

Cartilage endplate (CEP) plays important roles in the onset and progression of intervertebral disc degeneration (IVDD). Icariin (ICA) is the major active ingredient of Herba Epimedii and has various biological activities such as anti-inflammatory and antioxidant, which is used to treat many degenerative diseases. However, the effects and mechanism of ICA on endplate chondrocytes are still unclear. Herein, we studied the effects of ICA on CEP degeneration and elucidated the underlying mechanisms. Endplate chondrocytes were isolated, and TNF-α and TBHP were applied to mimic an IVDD pathological environment. Also, an IVDD mice model was established by transection of bilateral facet joints to investigate the protective effect of ICA in vivo. We found that ICA treatment inhibited the chondrocytes apoptosis and the decrease of extracellular matrix production in a dose-dependent manner. Our in vivo experiments demonstrated that ICA could ameliorate IVDD development and CEP calcification. We also found that the ICA-activated Nrf-2/HO-1 pathway thus promoted the Parkin-mediated mitophagy process and inhibited chondrocytes ferroptosis, thus alleviated redox imbalance and mitochondrial dysfunction and eventually improved cell survival. Knockdown of Nrf-2 using siRNA reversed the protective effect of ICA on endplate chondrocytes apoptosis and degeneration. In conclusion, our study demonstrated that ICA could protect against CEP degeneration and calcification under IVDD pathological conditions, the associated mechanism may be related to Nrf-2/HO-1-mediated mitophagy activation and ferroptosis inhibition. Our results suggest that ICA may be a potential effective medicine for IVDD prevention and treatment.

Dihydroartemisinin Attenuated Intervertebral Disc Degeneration via Inhibiting PI3K/AKT and NF-κB Signaling Pathways

Intervertebral disc degeneration (IDD) is the leading cause of low back pain (LBP). However, effective therapeutic drugs for IDD remain to be further explored. Inflammatory cytokines play a pivotal role in the onset and progression of IDD. Dihydroartemisinin (DHA) has been well reported to have powerful anti-inflammatory effects, but whether DHA could ameliorate the development of IDD remained unclear. In this study, the effects of DHA on extracellular matrix (ECM) metabolism and cellular senescence were firstly investigated in nucleus pulposus cells (NPCs) under tumor necrosis factor alpha (TNFα)-induced inflammation. Meanwhile, AKT agonist sc-79 was used to determine whether DHA exerted its actions through regulating PI3K/AKT and NF-κB signaling pathways. Next, the therapeutic effects of DHA were tested in a puncture-induced rat IDD model. Finally, we detected the activation of PI3K/AKT and NF-κB signaling pathways in clinical degenerative nucleus pulposus specimens. We demonstrated that DHA ameliorated the imbalance between anabolism and catabolism of extracellular matrix and alleviated NPCs senescence induced by TNFα in vitro. Further, we illustrated that DHA mitigated the IDD progression in a puncture-induced rat model. Mechanistically, DHA inhibited the activation of PI3K/AKT and NF-κB signaling pathways induced by TNFα, which was undermined by AKT agonist sc-79. Molecular docking predicted that DHA bound to the PI3K directly. Intriguingly, we also verified the activation of PI3K/AKT and NF-κB signaling pathways in clinical degenerative nucleus pulposus specimens, suggesting that DHA may qualify itself as a promising drug for mitigating IDD.

Exosomes and exosomal miRNAs: A new therapy for intervertebral disc degeneration

Low back pain has been found as a major cause of global disease burden and disability. Intervertebral disc degeneration is recognized as the vital factor causing low back pain. Intervertebral disc degeneration has a complex mechanism and cannot be avoided. Traditional strategies for the treatment of intervertebral disc degeneration cannot meet the needs of intervertebral disc regeneration, so novel treatment methods are urgently required. Exosomes refer to extracellular vesicles that can be released by most cells, and play major roles in intercellular material transport and information transmission. MicroRNAs have been identified as essential components in exosomes, which can be selectively ingested by exosomes and delivered to receptor cells for the regulation of the physiological activities and functions of receptor cells. Existing studies have progressively focused on the role of exosomes and exosomal microRNAs in the treatment of intervertebral disc degeneration. The focus on this paper is placed on the changes of microenvironment during intervertebral disc degeneration and the biogenesis and mechanism of action of exosomes and exosomal microRNAs. The research results and deficiencies of exosomes and exosomal microRNAs in the regulation of apoptosis, extracellular matrix homeostasis, inflammatory response, oxidative stress, and angiogenesis in intervertebral disc degeneration are primarily investigated. The aim of this paper is to identify the latest research results, potential applications and challenges of this emerging treatment strategy.

Curcumin encapsulated polylactic acid nanoparticles embedded in alginate/gelatin bioinks for in situ immunoregulation: Characterization and biological assessment

Curcumin is a known naturally occurring anti-inflammatory agent derived from turmeric, and it is commonly used as a herbal food supplement. Here, in order to overcome the inherent hydrophobicity of curcumin (Cur), polylactic acid (PLA) nanoparticles (NPs) were synthesised using a solvent evaporation, and an oil-in-water emulsion method used to encapsulate curcumin. Polymeric NPs also offer the ability to control rate of drug release. The newly synthesised NPs were analysed using a scanning electron microscope (SEM), where results show the NPs range from 50 to 250 nm. NPs containing graded amounts of curcumin (0 %, 0.5 %, and 2 %) were added to cultures of NIH3T3 fibroblast cells for cytotoxicity evaluation using the Alamar Blue assay. Then, the curcumin NPs were incorporated into an alginate/gelatin solution, prior to crosslinking using a calcium chloride solution (200 nM). These hydrogels were then characterised with respect to their chemical, mechanical and rheological properties. Following hydrogel optimization, hydrogels loaded with NP containing 2 % curcumin were selected as a candidate as a bioink for three-dimensional (3D) printing. The biological assessment for these bioinks/hydrogels were conducted using THP-1 cells, a human monocytic cell line. Cell viability and immunomodulation were evaluated using lactate dehydrogenase (LHD) and a tumour necrosis factor alpha (TNF-α) enzyme-linked immunosorbent (ELISA) assay, respectively. Results show that the hydrogels were cytocompatible and supressed the production of TNF-α. These bioactive hydrogels are printable, supress immune cell activation and inflammation showing immense potential for the fabrication of tissue engineering constructs.

Mechanisms of Intervertebral Disc Degeneration Treatment with Deer Antlers Based on Network Pharmacology and Molecular Docking

Background

With the aging of the population, the prevalence of IVDD increases preoperatively. How to better treat IVDD has become an important clinical issue. Deer antlers proved to have a great effect on the treatment of IVDD in many studies, but the molecular mechanism has not been clarified.

Objective

To investigate the molecular mechanism and target of deer antlers in the treatment of IVDD.

Methods

Compounds from deer antlers were collected and targets were predicted using HERB, TCMSP, TCMID, SwissADME, and SwissTargetPrediction. Collection of disease targets for IVDD was done using GeneCards, TTD, DrugBank, DisGeNET, and OMIM. Cytoscape 3.7.2, AutoDock Vina (v1.1.2), and R software were used for data analysis and the construction of network diagrams.

Results

A total of 5 active compounds from deer antlers were screened and 104 therapeutic targets were predicted. A total of 1023 IVDD disease targets were collected. Subsequently, PPI network prediction analysis was performed for disease and treatment targets, and 112 core targets were collected after screening. After obtaining the core target, we used the clusterProfiler software package of R software to carry out GO and KEGG enrichment analyses for the core target and plot the bubble maps. According to the GO enrichment results, the main biological processes of IVDD treatment by deer antlers lie in the rhythmic process, mRNA catabolic process, and G1/S transition of the mitotic cell cycle. KEGG results were mainly related to the PI3K-Akt signaling pathway, thyroid hormone signaling pathway, and Notch signaling pathway. Molecular docking results showed that estrone had the best docking results on ESR1.

Conclusion

Deer antlers are rich in various compounds that can prevent the development of IVDD by upregulating the PI3K-Akt signaling pathway and Notch signaling pathway. Its key compounds estradiol and estrone can reduce the inflammatory response and oxidative stress in tissues and organs, thus slowing down the progression of IVDD. Estrone, the active compound in deer antlers, was found by molecular docking to have good results against ESR1, the target of the disease, which may be a potential site for drug therapy.

Hydrogel-Embedded Poly(Lactic-co-Glycolic Acid) Microspheres for the Delivery of hMSC-Derived Exosomes to Promote Bioactive Annulus Fibrosus Repair

OBJECTIVE

Intervertebral disk degeneration is a prevalent postoperative complication after discectomy, underscoring the need to develop preventative and bioactive treatment strategies that decelerate degeneration and seal annulus fibrosus (AF) defects. Human mesenchymal stem cell-derived exosomes (MSC-Exos) hold promise for cell-free bioactive repair; however, their ability to promote AF repair is poorly understood. The objective of this study was to evaluate the ability of MSC-Exos to promote endogenous AF repair processes and integrate MSC-Exos within a biomaterial delivery system.

DESIGN

We characterize biophysical and biochemical properties of normoxic (Nx) and hypoxic (Hx) preconditioned MSC-Exos from young, healthy donors and examine their effects on AF cell proliferation, migration, and gene expression. We then integrate a poly(lactic-co-glycolic acid) microsphere (PLGA µSphere) delivery platform within an interpenetrating network hydrogel to facilitate sustained MSC-Exo delivery.

RESULTS

Hx MSC-Exos led to a more robust response in AF cell proliferation and migration than Nx MSC-Exos and was selected for a downstream protection experiment. Hx MSC-Exos maintained a healthy AF cell phenotype under a TNFα challenge in vitro and attenuated catabolic responses. In all functional assays, AF cell responses were more sensitive to Hx MSC-Exos than Nx MSC-Exos. PLGA µSpheres released MSC-Exos over a clinically relevant timescale without affecting hydrogel modulus or pH upon initial embedment and µSphere degradation.

CONCLUSIONS

This MSC-Exo treatment strategy may offer benefits of stem cell therapy without the need for exogenous stem cell transplantation by stimulating cell proliferation, promoting cell migration, and protecting cells from the degenerative proinflammatory microenvironment.

Encapsulated saponin by ferritin nanoparticles attenuates the murine pneumococcal pneumonia

Streptococcus pneumonia is classified as a gram-positive bacterial pathogen that causes asymptomatic or symptomatic respiratory infections. This study aimed to evaluate the effects of designed encapsulated saponin by ferritin nanoparticles in the healing progression of experimental bacterial pneumonia. The saponin encapsulated by ferritin followed the disassembly-reassembly process. Pneumonia was induced by the preparation of Streptococcus pneumonia. A total of 50 NMRI mice were divided into control, pneumonia, pneumonia + ferritin, pneumonia + saponin, and pneumonia + encapsulated saponin by ferritin nanoparticles (Nano Saponin) groups. ELISA, Real-time PCR, and Western blotting were used to measure sera IL-4 level, tumor necrosis factor-alpha (Tnf-α), and protein cyclooxygenase-2 (COX-2) gene expression, respectively. COX-2 protein expression, Tnf-α gene expression, and serum levels of IL-4 reduced compared to the pneumonia group. The histopathology results revealed that the rates of inflammation, mucus secretion, pulmonary hemorrhage, thickening of the alveoli wall, and secretion of inflammatory cells were lower in the Nano Saponin group than in the other groups. This study suggests that Glycyrrhiza glabra saponin and encapsulated saponin by ferritin nanoparticles oral consumption with anti-Tnf-α effect besides decreasing protein expression of COX-2 allows mice with pneumonia to recover.

The Japan Frailty Scale is a promising screening test for frailty and pre-frailty in Japanese elderly people

Frailty is one of the most important problems in a super-aged society. It is necessary to identify frailty quickly and easily at the bedside. We developed a simple patient-reported frailty screening scale, the Japan Frailty Scale (JFS), based on the aging concept of Kampo medicine. Eight candidate questions were prepared by Kampo medicine experts, and a simple prediction model was created in the development cohort (n=434) and externally validated in an independent validation cohort (n=276). The physical indicators and questionnaires associated with frailty were also comprehensively evaluated. The reference standard for frailty or pre-frailty was determined based on the Kihon checklist. In the development cohort, four questions, nocturia (0-2), lumbago (0-2), cold sensitivity (0-2), exhaustion (0-4), and age (0-1) were selected by multivariable logistic regression analysis. The total JFS score is 0-11. Receiver-operating characteristic curve analysis of the JFS for identifying frailty status showed moderately good discrimination (area under the curve (AUC) =0.78, 95% confidence interval (CI): 0.73-0.82). At the JFS cutoff value of 3/4 for frailty or pre-frailty, the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 86.9%, 53.3%, 62.8%, and 81.7%, respectively. External validation of the JFS showed moderately good discrimination (AUC=0.76, 95% CI: 0.70-0.81). The sensitivity, specificity, PPV, and NPV were 79.9%, 61.4%, 69.3%, and 73.7%, respectively. These results indicate that the JFS is a promising patient-reported clinical scale for early identification of pre-frail/frail patients at the bedside in primary care.

Modulation of Inflammatory Mediators and Microglial Activation Through Physical Exercise in Alzheimer's and Parkinson's Diseases

Neuroinflammation is an inflammatory process in the central nervous system (CNS), in addition to being one of the main features of Alzheimer's disease (AD) and Parkinson's disease (PD). Microglia are known for their immune functions and have multiple reactive phenotypes related to the types of stages involving neurodegenerative diseases. Depending on the state of activation of microglia in the CNS, it can be neuroprotective or neurotoxic. In this context, AD is a neurodegenerative and neuroinflammatory disease characterized by the deposition of beta-amyloid plaques, formation of fibrillar tangles of tau protein, and loss of neurons due to neurotoxic activation of microglia. However, PD is characterized by the loss of dopaminergic neurons in the substantia nigra and accumulation of alpha-synuclein in the cortical regions, spinal cord, and brain stem, which occurs by microglial activation, contributing to the neuroinflammatory process. In this aspect, the activation of microglia in both pathologies triggers high levels of inflammatory markers, such as interleukins, and causes the neuroinflammatory process of the diseases. Thus, physical exercise is pointed out as neuroprotective, as it can act to strengthen neurogenesis and reduce the inflammatory process. Therefore, the present review addresses the neuroprotective effect of microglia after different types of physical exercise protocols and evaluates the activity and effects of inflammatory and anti-inflammatory parameters and mechanisms of AD and PD. This review will discuss the anti-inflammatory effects of physical exercise through microglia activation with neuroprotective activity and the role of pro-and anti-inflammatory cytokines in AD and PD.