1
|
Xu T, Chen G, Li J, Zhang Y. Exploring causal correlations between inflammatory cytokines and intervertebral disc degeneration: A Mendelian randomization. JOR Spine 2024; 7:e1349. [PMID: 38993524 PMCID: PMC11237178 DOI: 10.1002/jsp2.1349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 06/18/2024] [Accepted: 06/20/2024] [Indexed: 07/13/2024] Open
Abstract
Background Inflammatory cytokines have been reported to be related to intervertebral disc degeneration (IVDD) in several previous studies. However, it remains unclear about the causal relationship between inflammatory cytokines and IVDD. This study employs Mendelian randomization (MR) to analyze the causal link between inflammatory cytokines and the risk of IVDD. Method We used genetic variants associated with inflammatory cytokines from a meta-analysis of genome-wide association study (GWAS) in 8293 Finns as instrumental variables and IVDD data were sourced from the FinnGen consortium. The main analytical approach utilized Inverse-Variance Weighting (IVW) with random effects to assess the causal relationship. Additionally, complementary methods such as MR-Egger, weighted median, simple mode, weighted mode, and MR pleiotropy residual sum and outlier were employed to enhance the robustness of the final results. Result We found interferon-gamma (IFN-γ, p = 2.14 × 10-6, OR = 0.870, 95% CI = 0.821-0.921), interleukin-1 beta (IL-1b, p = 0.012, OR = 0.951, 95% CI = 0.914-0.989), interleukin-4 (IL-4, p = 0.034, OR = 0.946, 95% CI = 0.899-0.996), interleukin-18 (IL-18, p = 0.028, OR = 0.964, 95% CI = 0.934-0.996), granulocyte colony-stimulating factor (GCSF, p = 0.010, OR = 0.919, 95% CI = 0.861-0.980), and Stromal cell-derived factor 1a (SDF1a, p = 0.014, OR = 1.072, 95% CI = 1.014-1.134) were causally associated with risk of IVDD. Conclusion Our MR analyses found a potential causal relationship between six inflammation cytokines (IFN-γ, IL-1b, IL-4, IL-18, SDF1a, and GCSF) and altered IVDD risk.
Collapse
Affiliation(s)
- Tao Xu
- Department of Orthopedics, Tongji Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanPeople's Republic of China
| | - Guangzi Chen
- Department of Orthopedics, Tongji Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanPeople's Republic of China
| | - Jian Li
- Department of OrthopaedicsThird Hospital of Shanxi Medical University, Shanxi Bethune Hospital, Shanxi Academy of Medical Sciences, Tongji Shanxi HospitalTaiyuanPeople's Republic of China
| | - Yingchi Zhang
- Department of Orthopedics, Tongji Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanPeople's Republic of China
- Department of Traumatology, Tongji Hospital, Tongji Medical CollegeHuazhong University of Science and TechnologyWuhanPeople's Republic of China
| |
Collapse
|
2
|
Yao Q, Lei Y, Zhang Y, Chen H, Dong X, Ye Z, Liang H. EZH2-H3K27me3-Mediated Epigenetic Silencing of DKK1 Induces Nucleus Pulposus Cell Pyroptosis in Intervertebral Disc Degeneration by Activating NLRP3 and NAIP/NLRC4. Inflammation 2024:10.1007/s10753-024-02096-1. [PMID: 39052181 DOI: 10.1007/s10753-024-02096-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 06/14/2024] [Accepted: 07/01/2024] [Indexed: 07/27/2024]
Abstract
Nucleus pulposus (NP) cell pyroptosis is crucial for intervertebral disc degeneration (IDD). However, the precise mechanisms underlying pyroptosis in IDD remain elusive. Therefore, this study aimed to investigate how dickkopf-1 (DKK1) influences NP cell pyroptosis and delineate the regulatory mechanisms of IDD. Behavioral tests and histological examinations were conducted in rat IDD models to assess the effect of DKK1 on the structure and function of intervertebral discs. Detected pyroptosis levels using Hoechst 33,342/propidium iodide (PI) double staining, and determined pyroptosis-related protein expression via western blotting. The cellular mechanisms of DKK1 in pyroptosis were explored in interleukin (IL)-1β-induced NP cells transfected with or without DKK1 overexpression plasmids (oe-DKK1). In addition, IL-1β-treated NP cells transfected with sh-EZH2 and/or sh-DKK1 were utilized to clarify the interplay between the enhancer of zeste homologue 2 (EZH2) and DKK1 in pyroptosis. Additionally, the epigenetic regulation of DKK1 by EZH2 was explored in NP cells treated with the EZH2 inhibitors GSK126/DZNep. DKK1 expression decreased in IDD rats. Transfection with oe-DKK1 reduced pro-inflammatory factors and extracellular matrix markers in IDD rats. In IL-1β-induced NP cells, DKK1 overexpression suppressed pyroptosis and inhibited the NLRP3 and NAIP/NLRC4 inflammasome activation. EZH2 knockdown increased DKK1 expression and reduced pyroptosis-related proteins. Conversely, DKK1 downregulation reversed the inhibitory effects of EZH2 knockdown on pyroptosis. Furthermore, EZH2 suppressed DKK1 expression via H3K27 methylation at the DKK1 promoter. EZH2 negatively regulates DKK1 expression via H3K27me3 methylation, promoting NP cell pyroptosis in IDD patients. This regulatory effect involves the activation of NLRP3 and NAIP/NLRC4 inflammasomes.
Collapse
Affiliation(s)
- Qijun Yao
- Department of Bone and Soft Tissue Repair and Reconstructive Surgery, The Second Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning, 116000, China
| | - Yue Lei
- Department of Bone and Soft Tissue Repair and Reconstructive Surgery, The Second Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning, 116000, China
| | - Yongxu Zhang
- Department of Bone and Soft Tissue Repair and Reconstructive Surgery, The Second Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning, 116000, China
| | - Haoran Chen
- Department of Bone and Soft Tissue Repair and Reconstructive Surgery, The Second Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning, 116000, China
| | - Xiaowei Dong
- Department of Bone and Soft Tissue Repair and Reconstructive Surgery, The Second Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning, 116000, China
| | - Zhiqiang Ye
- Department of Bone and Soft Tissue Repair and Reconstructive Surgery, The Second Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning, 116000, China
| | - Haidong Liang
- Department of Bone and Soft Tissue Repair and Reconstructive Surgery, The Second Hospital of Dalian Medical University, No. 467 Zhongshan Road, Dalian, Liaoning, 116000, China.
| |
Collapse
|
3
|
Tu H, Gao Q, Zhou Y, Peng L, Wu D, Zhang D, Yang J. The role of sirtuins in intervertebral disc degeneration: Mechanisms and therapeutic potential. J Cell Physiol 2024. [PMID: 38922861 DOI: 10.1002/jcp.31328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 04/27/2024] [Accepted: 05/13/2024] [Indexed: 06/28/2024]
Abstract
Intervertebral disc degeneration (IDD) is one of the main causes of low back pain, which affects the patients' quality of life and health and imposes a significant socioeconomic burden. Despite great efforts made by researchers to understand the pathogenesis of IDD, effective strategies for preventing and treating this disease remain very limited. Sirtuins are a highly conserved family of (NAD+)-dependent deacetylases in mammals that are involved in a variety of metabolic processes in vivo. In recent years, sirtuins have attracted much attention owing to their regulatory roles in IDD on physiological activities such as inflammation, apoptosis, autophagy, aging, oxidative stress, and mitochondrial function. At the same time, many studies have explored the therapeutic effects of sirtuins-targeting activators or micro-RNA in IDD. This review summarizes the molecular pathways of sirtuins involved in IDD, and summarizes the therapeutic role of activators or micro-RNA targeting Sirtuins in IDD, as well as the current limitations and challenges, with a view to provide possible solutions for the treatment of IDD.
Collapse
Affiliation(s)
- Heng Tu
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Qian Gao
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yumeng Zhou
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Li Peng
- Key Laboratory of Bio-Resource & Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Dan Wu
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Demao Zhang
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Jing Yang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| |
Collapse
|
4
|
Bahar ME, Hwang JS, Lai TH, Byun JH, Kim DH, Kim DR. The Survival of Human Intervertebral Disc Nucleus Pulposus Cells under Oxidative Stress Relies on the Autophagy Triggered by Delphinidin. Antioxidants (Basel) 2024; 13:759. [PMID: 39061828 PMCID: PMC11273539 DOI: 10.3390/antiox13070759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Revised: 06/20/2024] [Accepted: 06/21/2024] [Indexed: 07/28/2024] Open
Abstract
Delphinidin (Delp), a natural antioxidant, has shown promise in treating age-related ailments such as osteoarthritis (OA). This study investigates the impact of delphinidin on intervertebral disc degeneration (IVDD) using human nucleus pulposus cells (hNPCs) subjected to hydrogen peroxide. Various molecular and cellular assays were employed to assess senescence, extracellular matrix (ECM) degradation markers, and the activation of AMPK and autophagy pathways. Initially, oxidative stress (OS)-induced hNPCs exhibited notably elevated levels of senescence markers like p53 and p21, which were mitigated by Delp treatment. Additionally, Delp attenuated IVDD characteristics including apoptosis and ECM degradation markers in OS-induced senescence (OSIS) hNPCs by downregulating MMP-13 and ADAMTS-5 while upregulating COL2A1 and aggrecans. Furthermore, Delp reversed the increased ROS production and reduced autophagy activation observed in OSIS hNPCs. Interestingly, the ability of Delp to regulate cellular senescence and ECM balance in OSIS hNPCs was hindered by autophagy inhibition using CQ. Remarkably, Delp upregulated SIRT1 and phosphorylated AMPK expression while downregulating mTOR phosphorylation in the presence of AICAR (AMPK activator), and this effect was reversed by Compound C, AMPK inhibitor. In summary, our findings suggest that Delp can safeguard hNPCs from oxidative stress by promoting autophagy through the SIRT1/AMPK/mTOR pathway.
Collapse
Affiliation(s)
- Md Entaz Bahar
- Department of Biochemistry and Convergence Medical Sciences, Institute of Medical Science, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea; (M.E.B.); (J.S.H.); (T.H.L.)
| | - Jin Seok Hwang
- Department of Biochemistry and Convergence Medical Sciences, Institute of Medical Science, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea; (M.E.B.); (J.S.H.); (T.H.L.)
| | - Trang Huyen Lai
- Department of Biochemistry and Convergence Medical Sciences, Institute of Medical Science, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea; (M.E.B.); (J.S.H.); (T.H.L.)
| | - June-Ho Byun
- Department of Oral and Maxillofacial Surgery, Institute of Medical Science, College of Medicine, Gyeongsang National University Hospital, Gyeongsang National University, Jinju 52727, Republic of Korea;
| | - Dong-Hee Kim
- Department of Orthopaedic Surgery, Institute of Medical Science, College of Medicine, Gyeongsang National University Hospital, Gyeongsang National University, Jinju 52727, Republic of Korea
| | - Deok Ryong Kim
- Department of Biochemistry and Convergence Medical Sciences, Institute of Medical Science, College of Medicine, Gyeongsang National University, Jinju 52727, Republic of Korea; (M.E.B.); (J.S.H.); (T.H.L.)
| |
Collapse
|
5
|
Peng B, Li Q, Chen J, Wang Z. Research on the role and mechanism of IL-17 in intervertebral disc degeneration. Int Immunopharmacol 2024; 132:111992. [PMID: 38569428 DOI: 10.1016/j.intimp.2024.111992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/28/2024] [Accepted: 03/30/2024] [Indexed: 04/05/2024]
Abstract
Intervertebral disc degeneration (IDD) is one of the primary causes of low back pain (LBP), which seriously affects patients' quality of life. In recent years, interleukin (IL)-17 has been shown to be highly expressed in the intervertebral disc (IVD) tissues and serum of patients with IDD, and IL-17A has been shown to promote IDD through multiple pathways. We first searched databases such as PubMed, Cochrane, Embase, and Web of Science using the search terms "IL-17 or interleukin 17″ and "intervertebral discs". The search period ranged from the inception of the databases to December 2023. A total of 24 articles were selected after full-text screening. The main conclusion of the clinical studies was that IL-17A levels are significantly increased in the IVD tissues and serum of IDD patients. The results from the in vitro studies indicated that IL-17A can activate signaling pathways such as the NF-κB and MAPK pathways; promote inflammatory responses, extracellular matrix degradation, and angiogenesis; and inhibit autophagy in nucleus pulposus cells. The main finding of the in vivo experiments was that puncture of animal IVDs resulted in elevated levels of IL-17A within the IVD, thereby inducing IDD. Clinical studies, in vitro experiments, and in vivo experiments confirmed that IL-17A is closely related to IDD. Therefore, drugs that target IL-17A may be novel treatments for IDD, providing a new theoretical basis for IDD therapy.
Collapse
Affiliation(s)
- Bing Peng
- Liuyang Hospital of Traditional Chinese Medicine, Liuyang City, Hunan Province, China; Tianjin University of Traditional Chinese Medicine, Tianjin, China
| | - Qian Li
- Liuyang Hospital of Traditional Chinese Medicine, Liuyang City, Hunan Province, China
| | - Jiangping Chen
- Liuyang Hospital of Traditional Chinese Medicine, Liuyang City, Hunan Province, China
| | - Zhexiang Wang
- Hunan Provincial Hospital of Integrative Traditional Chinese and Western Medicine, Changsha City, Hunan Province, China.
| |
Collapse
|
6
|
Sun K, Yan C, Dai X, Shi Y, Li F, Chen L, Sun J, Chen Y, Shi J. Catalytic Nanodots-Driven Pyroptosis Suppression in Nucleus Pulposus for Antioxidant Intervention of Intervertebral Disc Degeneration. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2024; 36:e2313248. [PMID: 38299823 DOI: 10.1002/adma.202313248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/17/2024] [Indexed: 02/02/2024]
Abstract
Low back pain resulting from intervertebral disc degeneration (IVDD) is a prevalent global concern; however, its underlying mechanism remains elusive. Single-cell sequencing analyses revealed the critical involvement of pyroptosis in IVDD. Considering the involvement of reactive oxygen species (ROS) as the primary instigator of pyroptosis and the lack of an efficient intervention approach, this study developed carbonized Mn-containing nanodots (MCDs) as ROS-scavenging catalytic biomaterials to suppress pyroptosis of nucleus pulposus (NP) cells to efficiently alleviate IVDD. Catalytic MCDs have superior efficacy in scavenging intracellular ROS and rescuing homeostasis in the NP microenvironment compared with N-acetylcysteine, a classical antioxidant. The data validates that pyroptosis plays a vital role in mediating the protective effects of catalytic MCDs against oxidative stress. Systematic in vivo assessments substantiate the effectiveness of MCDs in rescuing a puncture-induced IVDD rat model, further demonstrating their ability to suppress pyroptosis. This study highlights the potential of antioxidant catalytic nanomedicine as a pyroptosis inhibitor and mechanistically unveils an efficient strategy for the treatment of IVDD.
Collapse
Affiliation(s)
- Kaiqiang Sun
- Department of Orthopedic Surgery, Changzheng Hospital, Navy Medical University, Shanghai, 200003, P. R. China
- Department of Orthopedics, Naval Medical Center of PLA, Shanghai, 200052, P. R. China
| | - Chen Yan
- Department of Orthopedic Surgery, Changzheng Hospital, Navy Medical University, Shanghai, 200003, P. R. China
| | - Xinyue Dai
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China
| | - Yangyang Shi
- Department of Orthopedic Surgery, Changzheng Hospital, Navy Medical University, Shanghai, 200003, P. R. China
| | - Fudong Li
- Department of Orthopedic Surgery, Changzheng Hospital, Navy Medical University, Shanghai, 200003, P. R. China
| | - Liang Chen
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China
| | - Jingchuan Sun
- Department of Orthopedic Surgery, Changzheng Hospital, Navy Medical University, Shanghai, 200003, P. R. China
| | - Yu Chen
- Materdicine Lab, School of Life Sciences, Shanghai University, Shanghai, 200444, P. R. China
- Oujiang Laboratory (Zhejiang Lab for Regenerative Medicine, Vision and Brain Health), Wenzhou Institute of Shanghai University, Wenzhou, 325088, P. R. China
| | - Jiangang Shi
- Department of Orthopedic Surgery, Changzheng Hospital, Navy Medical University, Shanghai, 200003, P. R. China
| |
Collapse
|
7
|
Wang Z, Li X, Yu P, Zhu Y, Dai F, Ma Z, Shen X, Jiang H, Liu J. Role of Autophagy and Pyroptosis in Intervertebral Disc Degeneration. J Inflamm Res 2024; 17:91-100. [PMID: 38204989 PMCID: PMC10778915 DOI: 10.2147/jir.s434896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
Intervertebral disc degeneration is a chronic degenerative disease caused by the interaction of genetic and environmental factors, mainly manifested as lower back pain. At present, the diagnosis of intervertebral disc degeneration mainly relies on imaging. However, early intervertebral disc degeneration is usually insidious, and there is currently a lack of relevant clinical biomarkers that can reliably reflect early disease progression. Pyroptosis is a regulatory form of cell death triggered by the activation of inflammatory bodies and caspase, which can induce the formation of plasma membrane pores and cell swelling or lysis. Previous studies have shown that during the progression of intervertebral disc degeneration, sustained activation of inflammasomes leads to nuclear cell pyroptosis, which can occur in the early stages of intervertebral disc degeneration. Moreover, intervertebral disc nucleus pulposus cells adapt to the external environment through autophagy and maintain cellular homeostasis and studying the mechanism of autophagy in IDD and intervening in its pathological and physiological processes can provide new ideas for the clinical treatment of IDD. This review analyzes the effects of pyroptosis and autophagy on IDD by reviewing relevant literature in recent years, in order to explore the relationship between pyroptosis, autophagy and IDD.
Collapse
Affiliation(s)
- Zhiqiang Wang
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| | - Xiaochun Li
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| | - Pengfei Yu
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| | - Yu Zhu
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| | - Feng Dai
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| | - Zhijia Ma
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| | - Xueqiang Shen
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| | - Hong Jiang
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| | - Jintao Liu
- Department of Orthopedic Surgery, Suzhou TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Suzhou, 215009, People’s Republic of China
| |
Collapse
|
8
|
Yurube T, Takeoka Y, Kanda Y, Ryosuke K, Kakutani K. Intervertebral disc cell fate during aging and degeneration: apoptosis, senescence, and autophagy. NORTH AMERICAN SPINE SOCIETY JOURNAL (NASSJ) 2023; 14:100210. [PMID: 37090223 PMCID: PMC10113901 DOI: 10.1016/j.xnsj.2023.100210] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 02/25/2023] [Accepted: 03/06/2023] [Indexed: 03/12/2023]
Abstract
Background Degenerative disc disease, a major cause of low back pain and associated neurological symptoms, is a global health problem with the high morbidity, workforce loss, and socioeconomic burden. The present surgical strategy of disc resection and/or spinal fusion results in the functional loss of load, shock absorption, and movement; therefore, the development of new biological therapies is demanded. This achievement requires the understanding of intervertebral disc cell fate during aging and degeneration. Methods Literature review was performed to clarify the current concepts and future perspectives of disc cell fate, focused on apoptosis, senescence, and autophagy. Results The intervertebral disc has a complex structure with the nucleus pulposus (NP), annulus fibrosus (AF), and cartilage endplates. While the AF arises from the mesenchyme, the NP originates from the notochord. Human disc NP notochordal phenotype disappears in adolescence, accompanied with cell death induction and chondrocyte proliferation. Discs morphologically and biochemically degenerate from early childhood as well, thereby suggesting a possible involvement of cell fate including age-related phenotypic changes in the disease process. As the disc is the largest avascular organ in the body, nutrient deprivation is a suspected contributor to degeneration. During aging and degeneration, disc cells undergo senescence, irreversible growth arrest, producing proinflammatory cytokines and matrix-degradative enzymes. Excessive stress ultimately leads to programmed cell death including apoptosis, necroptosis, pyroptosis, and ferroptosis. Autophagy, the intracellular degradation and recycling system, plays a role in maintaining cell homeostasis. While the incidence of apoptosis and senescence increases with age and degeneration severity, autophagy can be activated earlier, in response to limited nutrition and inflammation, but impaired in aged, degenerated discs. The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) is a signal integrator to determine disc cell fate. Conclusions Cell fate and microenvironmental regulation by modulating PI3K/Akt/mTOR signaling is a potential biological treatment for degenerative disc disease.
Collapse
|
9
|
Liu Z, Zhu J, Liu H, Fu C. Natural products can modulate inflammation in intervertebral disc degeneration. Front Pharmacol 2023; 14:1150835. [PMID: 36874009 PMCID: PMC9978229 DOI: 10.3389/fphar.2023.1150835] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 02/08/2023] [Indexed: 02/18/2023] Open
Abstract
Intervertebral discs (IVDs) play a crucial role in maintaining normal vertebral anatomy as well as mobile function. Intervertebral disc degeneration (IDD) is a common clinical symptom and is an important cause of low back pain (LBP). IDD is initially considered to be associated with aging and abnormal mechanical loads. However, over recent years, researchers have discovered that IDD is caused by a variety of mechanisms, including persistent inflammation, functional cell loss, accelerated extracellular matrix decomposition, the imbalance of functional components, and genetic metabolic disorders. Of these, inflammation is thought to interact with other mechanisms and is closely associated with the production of pain. Considering the key role of inflammation in IDD, the modulation of inflammation provides us with new options for mitigating the progression of degeneration and may even cause reversal. Many natural substances possess anti-inflammatory functions. Due to the wide availability of such substances, it is important that we screen and identify natural agents that are capable of regulating IVD inflammation. In fact, many studies have demonstrated the potential clinical application of natural substances for the regulation of inflammation in IDD; some of these have been proven to have excellent biosafety. In this review, we summarize the mechanisms and interactions that are responsible for inflammation in IDD and review the application of natural products for the modulation of degenerative disc inflammation.
Collapse
Affiliation(s)
- Zongtai Liu
- Department of Spine Surgery, First Hospital of Jilin University, Changchun, China.,Department of Orthopedics, Affiliated Hospital of Beihua University, Jilin, China
| | - Jiabo Zhu
- Department of Orthopedics, Affiliated Hospital of Beihua University, Jilin, China
| | - Haiyan Liu
- Department of Orthopedics, Baicheng Central Hospital, Baicheng, China
| | - Changfeng Fu
- Department of Spine Surgery, First Hospital of Jilin University, Changchun, China
| |
Collapse
|