TGF-ß1 Inhibits Osteoclast Differentiation and Abnormal Angiogenesis in Intervertebral Disc Degeneration: Evidence from RNA Sequencing and Animal Studies.

OBJECTIVE: Mechanisms involved in developing intervertebral disc degeneration (IDD) are poorly understood, thus making developing effective therapies difficult. This study aimed to suggest a possible molecular mechanism, based on transcriptome sequencing-identified transforming growth factor (TGF-ß), underlying the effects on bone homeostasis in IDD. METHODS: A mouse model for IDD was established. Transcriptome sequencing of nucleus pulposus tissue from mice (n = 3) identified differentially expressed mRNAs and key genes impacting bone homeostasis. A protein-protein interaction network pinpointed core genes. GO and KEGG analysis revealed gene functions. Expression levels of TGF-ß1, tartrate-resistant acid phosphatase (TRAP), and cathepsin K (CTSK) were measured. Micro-CT evaluated vertebral structures and vascular imaging. Western Blot measured expression levels of Vegf, Opn, MMP3, and MMP13. Safranin O-Fast Green and TRAP staining were performed on intervertebral discs and endplates. RESULTS: Transcriptomic analysis found 1790 differentially expressed mRNAs in IDD mice. Twenty-eight genes related to bone homeostasis in IDD were identified. TGF-ß1 was confirmed as the core gene. GO and KEGG showed TGF-ß1 regulates osteoclast markers like CTSK and TRAP through pathways including NF-κB and MAPK. Experimental validation revealed lower TGF-ß1 expression in IDD mice than controls, and increased TRAP and CTSK expression. Micro-CT showed decreased bone mass and intervertebral disc space in IDD mice. Vascular imaging showed increased vascular volume in IDD cartilaginous endplates. Western blot displayed increased VEGF and OPN levels, but decreased MMP3 and MMP13 in IDD mice. Safranin O-fast green staining revealed severe IDD degeneration. However, TGF-ß1 injection improved bone parameters in IDD mice. In vitro experiments confirmed TGF-ß1 inhibits bone marrow macrophages differentiation into osteoclasts. CONCLUSION: From our data, we conclude that TGF-ß1 repressed osteoclast differentiation and aberrant bone-associated angiogenesis in cartilage endplates (EPs) to alleviate IDD, which may be instrumental for the therapeutic targeting of IDD.

Bibliometric and visual analysis of microglia-related neuropathic pain from 2000 to 2021.

Background: Microglia has gradually gained researchers' attention in the past few decades and has shown its promising prospect in treating neuropathic pain. Our study was performed to comprehensively evaluate microglia-related neuropathic pain via a bibliometric approach. Methods: We retrospectively reviewed publications focusing on microglia-related neuropathic pain from 2000 to 2021 in WoSCC. VOS viewer software and CiteSpace software were used for statistical analyses. Results: A total of 2,609 articles were finally included. A steady increase in the number of relevant publications was observed in the past two decades. China is the most productive country, while the United States shares the most-cited and highest H-index country. The University of London, Kyushu University, and the University of California are the top 3 institutions with the highest number of publications. Molecular pain and Pain are the most productive and co-cited journals, respectively. Inoue K (Kyushu University) is the most-contributed researcher and Ji RR (Duke University) ranks 1st in both average citations per article and H-index. Keywords analyses revealed that pro-inflammatory cytokines shared the highest burst strength. Sex differences, neuroinflammation, and oxidative stress are the emerging keywords in recent years. Conclusion: In the field of microglia-related neuropathic pain, China is the largest producer and the United States is the most influential country. The signaling communication between microglia and neurons has continued to be vital in this field. Sexual dimorphism, neuroinflammation, and stem-cell therapies might be emerging trends that should be closely monitored.

Intrathecal administration of botulinum toxin type a antagonizes neuropathic pain by countering increased vesicular nucleotide transporter expression in the spinal cord of chronic constriction injury of the sciatic nerve rats.

Botulinum toxin type A (BoNT/A) induces direct analgesic effects in neuropathic pain by inhibiting the release of substance P, calcitonin gene-related peptide (CGRP) and glutamate. Vesicular nucleotide transporter (VNUT) was responsible for the storage and release of ATP in vivo, and one of the mechanisms underlying neuropathic pain is VNUT-dependent release of extracellular ATP from dorsal horn neurons. However, the analgesic effect of BoNT/A by affecting the expression of VNUT remained largely unknown. Thus, in this study, we aimed to elucidate the antinociceptive potency and analgesic mechanism of BoNT/A in chronic constriction injury of the sciatic nerve (CCI) induced neuropathic pain. Our results showed that a single intrathecal injection of 0.1 U BoNT/A seven days after CCI surgery produced significant analgesic activity and decreased the expression of VNUT in the spinal cord of CCI rats. Similarly, BoNT/A inhibited the CCI-induced increase in ATP content in the rat spinal cord. Overexpression of VNUT in the spinal cord of CCI-induced rats markedly reversed the antinociceptive effect of BoNT/A. Furthermore, 33 U/mL BoNT/A dramatically reduced the expression of VNUT in pheochromocytoma (PC12) cells but overexpressing SNAP-25 increased VNUT expression in PC12 cells. Our current study is the first to demonstrate that BoNT/A is involved in neuropathic pain by regulating the expression of VNUT in the spinal cord in rats.

SKI knockdown suppresses apoptosis and extracellular matrix degradation of nucleus pulposus cells via inhibition of the Wnt/ß-catenin pathway and ameliorates disc degeneration.

This study aimed to determine the effects of SKI on interleukin (IL)-1ß-induced apoptosis of nucleus pulposus (NP) cells, intervertebral disc degeneration (IDD), and the Wnt signaling pathway. NP tissue specimens of different Pfirrmann grades (II-V) were collected from patients with different grades of IDD. Real-time polymerase chain reaction and western blotting were used to compare SKI mRNA and protein expression in NP tissues from patients. Using the IL-1ß-induced IDD model, NP cells were infected with lentivirus-coated si-SKI to downregulate the expression of SKI and treated with LiCl to evaluate the involvement of the Wnt/ß-catenin signaling pathway. Western blotting, immunofluorescence, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining were used to detect NP cell apoptosis, extracellular matrix (ECM) metabolism, and related protein expression changes in the Wnt/ß-catenin signaling pathway. To investigate the role of SKI in vivo, a rat IDD model was established by needle puncture of the intervertebral disc. Rats were injected with lentivirus-coated si-SKI and evaluated by magnetic resonance imaging (MRI), and hematoxylin and eosin (HE) and safranin O staining. SKI expression positively correlated with the severity of human IDD. In the IL-1ß-induced NP cell degeneration model, SKI expression increased significantly and reached a peak at 24 h. SKI knockdown protected against IL-1ß-induced NP cell apoptosis and ECM degradation. LiCl treatment reversed the protective effects of si-SKI on NP cells. Furthermore, lentivirus-coated si-SKI injection partially reversed the NP tissue damage in the IDD model in vivo. SKI knockdown reduced NP cell apoptosis and ECM degradation by inhibiting the Wnt/ß-catenin signaling pathway, ultimately protecting against IDD. Therefore, SKI may be an effective target for IDD treatment.

Transcription Factor SP2 Regulates Ski-mediated Astrocyte Proliferation In Vitro.

Transcription factors bind specific sequences upstream of the 5' end of their target genes to ensure proper spatiotemporal expression of the target gene. This study aims to demonstrate that the transcription factor SP2 regulates expression of the Ski gene, which has specific binding sites for SP2, and thus enables Ski to regulate astrocyte proliferation. The upstream regulation mechanism of astrocyte proliferation was explored to further regulate the formation of glial scar in specific time and space after spinal cord injury. JASPAR and UCSC databases were used to predict transcription factor binding and the threshold was gradually reduced to screen transcription factors upstream of Ski, leading to the identification of SP2. Next, we analyzed the correlation between the expression of SP2 and Ski in normal astrocytes and reactive astrocytes, as well as the changes in astrocyte proliferation. To confirm that SP2 regulates Ski during astrocyte proliferation, astrocytes were transfected siRNA targeting SP2 and then astrocyte proliferation were analyzed. Finally, a dual luciferase reporter assay and Chromatin immunoprecipitation (ChIP) assay confirmed that the promoter region of Ski contained a specific SP2 binding site. This is the first that SP2 has been identified and confirmed to play an important role in astrocyte proliferation by regulating Ski expression. These results may help identify novel targets for the treatment of spinal cord injury.

Curcumin Exerts Antinociceptive Effects in Cancer-Induced Bone Pain via an Endogenous Opioid Mechanism.

Cancer pain is one of the main complications in advanced cancer patients, and its management is still challenging. Therefore, there is an urgent need to develop novel pharmacotherapy for cancer pain. Several natural products have attracted the interest of researchers. In previous studies, curcumin has proved to exhibit antitumor, antiviral, antioxidant, anti-inflammatory, and analgesic effects. However, the analgesic mechanism of curcumin has not been elucidated. Thus, in this study, we aimed to elucidate the antinociceptive potency and analgesic mechanism of curcumin in cancer-induced bone pain. Our results showed that consecutive curcumin treatment (30, 60, 120 mg/kg, i.p., twice daily for 11 days) produced significant analgesic activity, but had no effect on the progress of the bone cancer pain. Notably, pretreatment with naloxone, a non-selective opioid receptor antagonist, markedly reversed the antinociceptive effect induced by curcumin. Moreover, in primary cultured rat dorsal root ganglion (DRG) neurons, curcumin significantly up-regulated the expression of proopiomelanocortin (Pomc) and promoted the release of ß-endorphin and enkephalin. Furthermore, pretreatment with the antiserum of ß-endorphin or enkephalin markedly attenuated curcumin-induced analgesia in cancer-induced bone pain. Our present study, for the first time, showed that curcumin attenuates cancer-induced bone pain. The results also suggested that stimulation of expression of DRG neurons ß-endorphin and enkephalin mediates the antinociceptive effect of curcumin in pain hypersensitivity conditions.

Cervical spinal tuberculosis combined with brucellosis.

INTRODUCTION: In some developing countries, tuberculosis and brucellosis, which are commom causes of spinal infections, are still common infectious diseases. However, co-occurrence of spinal tuberculosis and brucellosis is rare. METHODOLOGY: We report a case a 47-year-old male engaged in aquaculture with a medical history of numbness, weakness, fever, and night sweats in both upper limbs for about 10 days. Serum agglutination test (SAT) for Brucella revealed brucella infection. Cervical computed tomography (CT) scan and magnetic resonance imaging (MRI) suggested C6, C7 vertebral destruction and corresponding segmental nerve compression. Based on preoperative clinical symptoms and auxiliary examination, brucellar spondylitis was first suspected. According to the postoperative pathological examination, the patient was finally diagnosed as cervical spinal tuberculosis combined with brucellosis. RESULTS: The preoperative symptoms of the patient decreased significantly after surgery, and the patient recovered and leaved hospital within two weeks of starting treatment. At the 6-month follow-up, the patient's clinical symptoms completely disappeared, and all laboratory tests returned to normal. CONCLUSION: Cervical spinal tuberculosis combined with brucellosis is a relatively rare condition. In areas with high rates of tuberculosis and brucellosis, we should conduct comprehensive examinations to avoid misdiagnosis and missed diagnosis.

Role of HAND2-AS1 in human tumors.

Long noncoding RNAs (lncRNAs) are molecules more than 200 nucleotides in length. They play roles in various cells, mainly regulating cell growth, differentiation, and apoptosis. They also participate in the pathogenesis of many diseases. In fact, several studies have shown that lncRNAs function as cancer or tumor suppressor genes and play important roles in the occurrence and development of cancer in humans. New evidence has shown that lncRNA heart and neural crest derivatives expressed 2-antisense RNA 1 (lncRNA HAND2-AS1) hinders the occurrence and development of various tumors. Overexpression of HAND2-AS1 was found to be significantly related to the clinical and pathological characteristics of cancer patients, as well as the regulation of cell proliferation, apoptosis, invasion, metastasis, and energy metabolism through several possible mechanisms. Therefore, HAND2-AS1 may be a promising tumor biomarker and therapeutic target. Here, we review the biological functions, mechanisms, and potential clinical significance of HAND2-AS1 in numerous human tumors.

Spinal administration of the multi-functional opioid/neuropeptide FF agonist BN-9 produced potent antinociception without development of tolerance and opioid-induced hyperalgesia.

Chronic opioids treatment is impeded by the development of analgesic tolerance and opioid-induced hyperalgesia. Recent studies have shown that multi-functional opioid compounds produce analgesic activities with limited side effects. We developed a novel multi-functional peptide targeting opioid and neuropeptide FF receptors named BN-9, which produced potent and non-tolerance forming antinociceptive effect after supraspinal and systemic administrations. In the present study, the analgesic properties and potential side effects of intrathecal BN-9 were investigated in a range of preclinical rodent models. In complete Freund's adjuvant-induced inflammatory pain model, intrathecal BN-9 dose-dependently produced analgesic effect via opioid receptors, and the spinal antinociceptive effect was augmented by the neuropeptide FF receptor antagonist RF9. In contrast, in plantar incision-induced postoperative pain model, BN-9 exhibited potent anti-allodynic effect via opioid receptors and, at least partially, neuropeptide FF receptors. In mouse models of acetic acid-induced visceral pain and formalin pain, BN-9-induced spinal antinociception was mainly mediated by opioid receptors, independent of neuropeptide FF receptors. Furthermore, at the spinal level, chronic treatments with BN-9 did not lead to analgesic tolerance and cross-tolerance to morphine. Moreover, opioid-induced hyperalgesia was observed after repeated administration of morphine, but not BN-9. Taken together, our present study suggests that intrathecal BN-9 produces potent and non-tolerance forming antinociception, and does not cause opioid-induced hyperalgesia. Thus, BN-9 might serve as a promising lead compound in the development of multi-functional opioid analgesics with minimized side effects.

[Research progress on the role of adipokines in intervertebral disc degeneration].

OBJECTIVE: To review the research progress of the role and mechanism of adipokines in intervertebral disc degeneration (IVDD) in recent years. METHODS: The domestic and foreign literature related to adipokines in the process of IVDD was extensively reviewed. The types and functions of adipokines, the role and mechanism in the process of IVDD, and the application prospects of intervertebral disc biotherapy were reviewed. RESULTS: As a kind of bioactive substance secreted by adipose tissue, adipokine plays an important role in bone and joint diseases, metabolic diseases, and breast cancer. During IVDD, most adipokines can activate multiple signaling pathways by binding to autoreceptors, cause the proliferation and apoptosis of cells and proinflammatory and anti-inflammatory factors parasecretions in the intervertebral disc, and lead to imbalance of intradiscal metabolism and establishment of the initial inflammatory environment, and finally cause the IVDD. CONCLUSION: Adipokines, as a biologically active substance with metabolic and immunomodulatory functions, play important roles in the occurrence, development, and biological treatment of IVDD.

Peripheral and central sites of action for anti-allodynic activity induced by the bifunctional opioid/NPFF receptors agonist BN-9 in inflammatory pain model.

The activation of opioid and neuropeptide FF (NPFF) receptors plays important roles to modulate nociceptive signal in inflammatory pain states. Recently, BN-9 (Tyr-D. Ala-Gly-Phe-Gln-Pro-Gln-Arg-Phe-NH2) was pharmacologically characterized as a novel bifunctional agonist at both opioid and NPFF receptors. In the present study, the anti-allodynic activity and site(s) of action of BN-9 were assessed in a mouse model of carrageenan-induced inflammatory pain. In mice, BN-9 induced a dose-dependent anti-allodinic effect through opioid receptor at supraspinal or spinal level, and this effect was augmented by pretreatment with the NPFF receptor antagonist at the same level. In contrast, peripheral administration of BN-9 produced opioid receptor-mediated anti-allodynia, which was insensitive of the NPFF receptor antagonist. In addition, systemic BN-9 produced anti-allodynic effect via opioid receptors, independent of NPFF system. Therefore, these data indicate that central, peripheral or systemic administrations of BN-9 exert potent analgesic activities in inflammatory pain model via opioid receptor, and central effects of BN-9 are associated with NPFF system. Interestingly, systemic anti-allodynia of BN-9 was blocked by intraperitoneal administration of the opioid receptor antagonists, naloxone and naloxone methiodide, but not by intracerebroventricular injection of the peripherally acting opioid antagonist naloxone methiodide. Furthermore, BN-9-induced systemic anti-allodynia was reversed by intraplantar administration of naloxone, but not by peripheral administration of the NPFF receptor antagonist. Taken together, our data further suggest that systemic BN-9-induced anti-allodynic effect is mainly mediated by peripheral opioid receptors, independent of NPFF receptors.