P14ARF inhibits regional inflammation and vascularization in intervertebral disc degeneration by upregulating TIMP3

Exploration of the mode of death and potential death mechanisms of nucleus pulposus cells

Intervertebral disc degeneration (IVDD) is a common chronic orthopaedic disease in orthopaedics that imposes a heavy economic burden on people and society. Although it is well established that IVDD is associated with genetic susceptibility, ageing and obesity, its pathogenesis remains incompletely understood. Previously, IVDD was thought to occur because of excessive mechanical loading leading to destruction of nucleus pulposus cells (NPCs), but studies have shown that IVDD is a much more complex process associated with inflammation, metabolic factors and NPCs death and can involve all parts of the disc, characterized by causing NPCs death and extracellular matrix (ECM) degradation. The damage pattern of NPCs in IVDD is like that of some programmed cell death, suggesting that IVDD is associated with programmed cell death. Although apoptosis and pyroptosis of NPCs have been studied in IVDD, the pathogenesis of intervertebral disc degeneration can still not be fully elucidated by using only traditional cell death modalities. With increasing research, some new modes of cell death, PANoptosis, ferroptosis and senescence have been found to be closely related to intervertebral disc degeneration. Among these, PANoptosis combines essential elements of pyroptosis, apoptosis and necroptosis to form a highly coordinated and dynamically balanced programmed inflammatory cell death process. Furthermore, we believe that PANoptosis may also crosstalk with pyroptosis and senescence. Therefore, we review the progress of research on multiple deaths of NPCs in IVDD to provide guidance for clinical treatment.

A systematic morphology study on the effect of high glucose on intervertebral disc endplate degeneration in mice

To explore the relationship between diabetes and intervertebral disc degeneration in mice and the associated underlying mechanism. Four-week-old male Kunming mice were used to model diabetes using a high-fat diet combined with streptozotocin injection. After 6 months, morphological and pathological changes in L4-L6 intervertebral discs were detected by magnetic resonance imaging, micro-CT and histological staining. Immunostaining of CD31, F4/80 and CD16/32 receptors was used to detect vascular invasion and inflammatory infiltration in endplates; the exact changes were then explored by the transmission electron microscopy. The nucleus pulposus of the control and the diabetic group had a clear boundary and regular shape without collapse, while endplate calcification and chondrocyte abnormality in the diabetic group were more obvious. Immunofluorescence confirmed that compared to control, expression levels of CD31 (vascular endothelial marker) and F4/80 (monocyte/macrophage marker) in the diabetic group were significantly increased (P < 0.05), with an elevated number of F4/80 (+)/CD16/32 (+) cells (P < 0.05). The morphology of endplates was observed by transmission electron microscopy, which showed monocytes/macrophage accumulation in the endplate of the diabetic group, accompanied by increased vascular density, collagen fiber distortion and chondrocyte abnormality. In a conclusion, diabetes promotes endplate degeneration with vascular invasion, monocyte/macrophage infiltration and inflammation in mice.

Treatment outcomes of injectable thermosensitive hydrogel containing bevacizumab in intervertebral disc degeneration

Intervertebral disc (IVD) degeneration (IDD) is a common musculoskeletal disease and its treatment remains a clinical challenge. It is characterised by reduced cell numbers and degeneration of the extracellular matrix (ECM). Nucleus pulposus (NP) cells play a crucial role in this process. The purpose of this study is to explore the role of bevacizumab, a vascular endothelial growth factor (VEGF) inhibitor, in the treatment of IDD through local drug delivery. High expression of VEGF was observed in degenerating human and rat IVDs. We demonstrated that MMP3 expression was decreased and COL II synthesis was promoted, when VEGF expression was inhibited by bevacizumab, thereby improving the degree of disc degeneration. Thus, these findings provide strong evidence that inhibition of VEGF expression by local delivery of bevacizumab is safe and effective in ameliorating disc degeneration in rats. The injectable thermosensitive PLGA-PEG-PLGA hydrogels loaded with bevacizumab is a potential therapeutic option for disc degeneration.

Exosomes Immunity Strategy: A Novel Approach for Ameliorating Intervertebral Disc Degeneration

Low back pain (LBP), which is one of the most severe medical and social problems globally, has affected nearly 80% of the population worldwide, and intervertebral disc degeneration (IDD) is a common musculoskeletal disorder that happens to be the primary trigger of LBP. The pathology of IDD is based on the impaired homeostasis of catabolism and anabolism in the extracellular matrix (ECM), uncontrolled activation of immunologic cascades, dysfunction, and loss of nucleus pulposus (NP) cells in addition to dynamic cellular and biochemical alterations in the microenvironment of intervertebral disc (IVD). Currently, the main therapeutic approach regarding IDD is surgical intervention, but it could not considerably cure IDD. Exosomes, extracellular vesicles with a diameter of 30–150 nm, are secreted by various kinds of cell types like stem cells, tumor cells, immune cells, and endothelial cells; the lipid bilayer of the exosomes protects them from ribonuclease degradation and helps improve their biological efficiency in recipient cells. Increasing lines of evidence have reported the promising applications of exosomes in immunological diseases, and regarded exosomes as a potential therapeutic source for IDD. This review focuses on clarifying novel therapies based on exosomes derived from different cell sources and the essential roles of exosomes in regulating IDD, especially the immunologic strategy.

Network pharmacology and experimental validation to explore the molecular mechanisms of Bushen Huoxue for the treatment of premature ovarian insufficiency

Bushen Huoxue (BSHX) has been applied in clinical traditional Chinese medicine treatment, and has definitive clinical efficacy in the treatment of Premature Ovarian Insufficiency (POI) in China. However, little is known of the underlying mechanism of BSHX. The purpose of this paper is to study the pharmacological mechanisms of BSHX acting on POI based on a pharmacology and experimental validation. The pharmacological database of chinese medicine system and analysis platform (TCMSP) were used to search the effective active ingredients and potential action targets of BSHX. Drugbank, Online Mendelian Inheritance in Man (OMIM), Genecards, and Disgenet databases were used to obtain relevant targets of POI. Gene Ontology (GO) enrichment, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment, and the visual network of protein-protein interaction network were constructed by FunRich3.1. Pymol software, and Auto Dock tools 1.5.6 were used for molecular docking. Murine model of POI was used to further investigate the mechanism of BSHX against on POI. Finally, 127 active compounds were collected from TCMSP database, and 215 active targets were identified. There were 1366 targets related to POI and 99 targets of BSHX for the treatment of POI. Quercetin, kaempferol, and stigmasterol were recognized as the most effective compounds corresponding to targets. The top three genes according to degree value are TP53, Akt1, and VEGFA. Further, the results of GO and KEGG enrichment analysis revealed that those core targets were mainly enriched on TRAIL and TGF-β receptor signaling. The results of molecular docking showed that stigmasterol had good binding ability to Akt1. Moreover, experimental validation suggests that BSHX significantly Increased the expression of TGF-β1 and Smad2/3, regulating the release of serum sex hormones, which include Follicular stimulating hormone (FSH), Estradiol (E2), and Antimullerin hormone (AMH).

RETRACTED: Role of microRNA-15a-5p/Sox9/NF-κB axis in inflammatory factors and apoptosis of murine nucleus pulposus cells in intervertebral disc degeneration

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Editor-in-Chief. Concerns were raised over the provenance of the flow cytometry plots in Figures 6G and 7F, as detailed here: https://pubpeer.com/publications/A46066C72A3E518DD6CA192362E0DC; and here: https://docs.google.com/spreadsheets/d/1r0MyIYpagBc58BRF9c3luWNlCX8VUvUuPyYYXzxWvgY/edit#gid=262337249. In addition, a portion of Figure 2G, ‘miR-15a-5p antagomir’ group appeared to contain image similarities with Figure 2G, ‘Oe-NC’ group. The journal requested that the corresponding author comment on these concerns and provide the raw data. The authors did not respond to this request and therefore the Editor-in-Chief decided to retract the article.

AF cell derived exosomes regulate endothelial cell migration and inflammation: Implications for vascularization in intervertebral disc degeneration

AIMS

The intervertebral disc is the largest avascular organ of the body. Vascularization of the disc has been typically regarded as a pathological feature of intervertebral disc degeneration (IDD). However, the underlying mechanism of vascularization in IDD is still unclear. The current study aimed to investigate the role of AF cell derived exosome (AF-exo) in the interaction with human umbilical vein endothelial cells (HUVECs) and its potential role in the regulation of vascularization in IDD.

MAIN METHODS

Human AF tissues were obtained from patients with IDD and idiopathic scoliosis. The AF-exo were isolated and identified by transmission electron microscopy (TEM), nanoparticle trafficking analysis (NTA) and Western blotting. Then, the AF-exo were used for HUVECs cultures. The migration of HUVECs was observed in 2D and 3D cultures. The inflammatory phenotype of HUVECs was examined by Real-time PCR and enzyme-linked immunosorbent assay (ELISA). Additionally, apoptosis of HUVECs were analyzed by flow cytometry.

KEY FINDINGS

Here, we for the first time found that AF cells could secrete AF-exo and that the AF-exo could be phagocytosed by HUVECs. Additionally, we found that degenerated AF-exo exerted pro-vascularization effect on HUVECs by promoting cell migration (in 2D and 3D cultures) and inflammatory factor expression including IL-6, TNF-α, MMP-3, MMP-13 and VEGF, whereas the application of non-degenerated AF-exo demonstrated inverse effects.

SIGNIFICANCE

These results showed that AF-exo is an essential regulator mediating intercellular communication between AF cells and HUVECs, suggesting its important role in vascularization in the intervertebral disc.

Dimethyl fumarate protects nucleus pulposus cells from inflammation and oxidative stress and delays the intervertebral disc degeneration

Lower back pain is a common problem in middle-aged and elderly people, and intervertebral disc degeneration (IVDD) is often the main cause. The present study aimed to explore the effects of dimethyl fumarate (DMF) on inflammation and oxidative stress in the intervertebral disc. C57/BL6 mice were used to construct an IVDD model by tail suspension and daily intraperitoneal injections of 10 mg/kg DMF were administered to analyze the effects of DMF on IVDD. In addition, human nucleus pulposus (NP) cells were cultured and stimulated cells with recombinant human IL-1β and DMF to examine the effects of DMF on inflammation and oxidative stress in NP cells. DMF significantly increased the intervertebral disc height index of mice and inhibited the degradation of the extracellular matrix of mouse NP tissue. In addition, DMF also decreased the expression of inflammatory factors [including IL-6, IL-8, matrix metalloproteinase (MMP)3 and MMP13] in NP cells. In terms of oxidative stress, DMF significantly increased the antioxidative stress response in NP cells and reduced endoplasmic reticulum stress. DMF also increased the activity of the nuclear factor erythroid 2-related factor (Nrf) 2/heme oxygenase (HO)-1 signaling pathway in NP cells and increased the phosphorylation of Akt. DMF also increased the anti-inflammatory and antioxidative ability of NP cells by promoting the activity of the Nrf2/HO-1 and PI3K/Akt signaling pathways, thus delaying IVDD.

Role of AP-2α/TGF-β1/Smad3 axis in rats with intervertebral disc degeneration

OBJECTIVE

Studies have proposed the role of AP-2α in human disease. However, few have focused on its effects on intervertebral disc degeneration (IDD). This study intends to discuss the role of AP-2α in IDD by regulating TGF-β1 and Smad3 expression.

METHODS

The AP-2α and TGF-β1 expression in IDD NP clinical samples was detected. Rat models of IDD were established by acupuncture. The rats were injected with AP-2α low expression adeno-associated virus or TGF-β1 high expression adeno-associated virus to observe their effects on pathological damages, NP cell apoptosis, matrix metalloproteinase-2 (MMP-2), MMP-9, Smad3, Aggrecan and collagen (Col)-2 expression in NP tissues. The NP cells were isolated and transfected with silenced AP-2α or overexpressed TGF-β1 vector to figure out their functions in growth, senescence and apoptosis.

RESULTS

AP-2α and TGF-β1 were upregulated in NP tissues of patients and rats with IDD. AP-2α silencing limited the activation of TGF-β1 signaling pathway. Reduced AP-2α ameliorated pathological changes, declined MMP-2, MMP-9 and Smad3 expression and elevated Aggrecan and Col-2 expression in NP tissues of rats with IDD, and speeded up the growth and depressed senescence and apoptosis of NP cells of rats with IDD. Up-regulating TGF-β1 weakened the effect of down-regulated AP-2α on NP tissues and cells in IDD.

CONCLUSION

Collectively, our study demonstrates that knockdown of AP-2α restricts TGF-β1 and Smad3 expression to promote proliferation and depress senescence and apoptosis of NP cells in rats with IDD.

Precondition of sevoflurane upregulates TIMP3 expression to alleviate myocardial ischemia/reperfusion injury

BACKGROUND

Previous studies have pointed out that sevoflurane (Sef) preconditioning could relieve myocardial ischemia/reperfusion (I/R) injury, but the mechanisms is still unknown.

METHODS

C57BL/6 mice model of myocardial I/R injury was established to evaluate the function of Sef. Briefly, Sef was inhaled before I/R operation. The levels of TIMP3, oxidative damage-related factors, and mitogen activated protein kinases (MAPKs) pathway-related factors were measured by qRT-PCR and western blot. Myocardial infarction (MI) area was detected by triphenyl tetrazolium chloride (TTC) staining assay.

RESULTS

Sef preconditioning reduced MI area in myocardial I/R injury mice and upregulated TIMP3 expression in myocardial tissues of I/R mice. In addition, downregulation of TIMP3 reversed the alleviating effects of Sef pretreatment on myocardial oxidative damage and inhibited the effect of Sef pretreatment on MAPKs pathway activity.

CONCLUSION

Sef preconditioning ameliorated myocardial I/R injury by modulating MAPKs pathway activity via upregulating TIMP3.