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Impaired transcription factor EB (TFEB) function and deficient autophagy activity have been shown to aggravate intervertebral disc (IVD) degeneration (IDD), yet the underlying mechanisms remain less clear. Protein posttranslational modifications (PTMs) are critical for determining TFEB trafficking and transcriptional activity. Here, we demonstrate that TFEB activity is controlled by protein methylation in degenerated nucleus pulposus cells (NPCs), even though TFEB itself is incapable of undergoing methylation. Specifically, protein phosphatase 1 catalytic subunit alpha (PPP1CA), newly identified to dephosphorylate TFEB, contains a K141 mono-methylated site. In degenerated NPCs, increased K141-methylation of PPP1CA disrupts its interaction with TEFB and subsequently blocks TEFB dephosphorylation and nuclear translocation, which eventually leads to autophagy deficiency and NPC senescence. In addition, we found that the PPP1CA-mediated targeting of TFEB is facilitated by the protein phosphatase 1 regulatory subunit 9B (PPP1R9B), which binds with PPP1CA and is also manipulated by K141 methylation. Further proteomic analysis revealed that the protein lysine methyltransferase suppressor of variegation 3-9 homologue 2 (SUV39H2) is responsible for the K141 mono-methylation of PPP1CA. Targeting SUV39H2 effectively mitigates NPC senescence and IDD progression, providing a potential therapeutic strategy for IDD intervention.
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Degeneración del Disco Intervertebral , Lisina , Humanos , Metilación , Degeneración del Disco Intervertebral/genética , Proteína Fosfatasa 1/genética , Proteómica , Autofagia , N-Metiltransferasa de Histona-Lisina , Procesamiento Proteico-Postraduccional , Factores de Transcripción Básicos con Cremalleras de Leucinas y Motivos Hélice-Asa-Hélice/genéticaRESUMEN
Neural stem cells (NSCs) are considered to be prospective replacements for neuronal cell loss as a result of spinal cord injury (SCI). However, the survival and neuronal differentiation of NSCs are strongly affected by the unfavorable microenvironment induced by SCI, which critically impairs their therapeutic ability to treat SCI. Herein, a strategy to fabricate PDGF-MP hydrogel (PDGF-MPH) microspheres (PDGF-MPHM) instead of bulk hydrogels is proposed to dramatically enhance the efficiency of platelet-derived growth factor mimetic peptide (PDGF-MP) in activating its receptor. PDGF-MPHM were fabricated by a piezoelectric ceramic-driven thermal electrospray device, had an average size of 9 µm, and also had the ability to activate the PDGFRß of NSCs more effectively than PDGF-MPH. In vitro, PDGF-MPHM exerted strong neuroprotective effects by maintaining the proliferation and inhibiting the apoptosis of NSCs in the presence of myelin extracts. In vivo, PDGF-MPHM inhibited M1 macrophage infiltration and extrinsic or intrinsic cells apoptosis on the seventh day after SCI. Eight weeks after SCI, the T10 SCI treatment results showed that PDGF-MPHM + NSCs significantly promoted the survival of NSCs and neuronal differentiation, reduced lesion size, and considerably improved motor function recovery in SCI rats by stimulating axonal regeneration, synapse formation, and angiogenesis in comparison with the NSCs graft group. Therefore, our findings provide insights into the ability of PDGF-MPHM to be a promising therapeutic agent for SCI repair.
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Hidrogeles , Traumatismos de la Médula Espinal , Ratas , Animales , Hidrogeles/farmacología , Hidrogeles/uso terapéutico , Factor de Crecimiento Derivado de Plaquetas/farmacología , Factor de Crecimiento Derivado de Plaquetas/uso terapéutico , Diferenciación Celular , Microesferas , Estudios Prospectivos , Traumatismos de la Médula Espinal/tratamiento farmacológico , Traumatismos de la Médula Espinal/patología , Péptidos/farmacología , Médula Espinal/patologíaRESUMEN
In recent decades, accumulating research on the interactions between microbiome homeostasis and host health has broadened new frontiers in delineating the molecular mechanisms of disease pathogenesis and developing novel therapeutic strategies. By transporting proteins, nucleic acids, lipids, and metabolites in their versatile bioactive molecules, extracellular vesicles (EVs), natural bioactive cell-secreted nanoparticles, may be key mediators of microbiota-host communications. In addition to their positive and negative roles in diverse physiological and pathological processes, there is considerable evidence to implicate EVs secreted by bacteria (bacterial EVs [BEVs]) in the onset and progression of various diseases, including gastrointestinal, respiratory, dermatological, neurological, and musculoskeletal diseases, as well as in cancer. Moreover, an increasing number of studies have explored BEV-based platforms to design novel biomedical diagnostic and therapeutic strategies. Hence, in this review, we highlight the recent advances in BEV biogenesis, composition, biofunctions, and their potential involvement in disease pathologies. Furthermore, we introduce the current and emerging clinical applications of BEVs in diagnostic analytics, vaccine design, and novel therapeutic development.
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Intervertebral disc degeneration (IDD) is the pathological reason of back pain and the therapeutic approaches are still unsatisfactory. Recently, mesenchymal stem cell-derived small extracellular vesicles (EVs) have emerged as the novel regenerative method for IDD. In this study, we intensively investigated the therapeutic mechanism of small EVs, and found that vasorin protein enriched in EVs promoted the proliferation and extracellular matrix anabolism of nucleus pulposus cells via the Notch1 signaling pathway. Then, we fabricated a thermoresponsive gel which composed of Pluronic F127 and decellularized extracellular matrix (FEC) for the delivery and sustained release of EVs. Besides, ex vivo and in vivo results showed that EVs embedded in FEC (EVs@FEC) ameliorate the disc degeneration efficiently and achieve better therapeutic effects than one-off EVs delivery. Collectively, these findings deepen the understanding of EVs mechanism in treating intervertebral disc degeneration, and also illustrate the promising capacity of sustained EVs release system for intervertebral disc regeneration.
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Vesículas Extracelulares , Degeneración del Disco Intervertebral , Células Madre Mesenquimatosas , Preparaciones de Acción Retardada/metabolismo , Vesículas Extracelulares/metabolismo , Humanos , Degeneración del Disco Intervertebral/tratamiento farmacológico , Degeneración del Disco Intervertebral/metabolismo , Degeneración del Disco Intervertebral/patología , Células Madre Mesenquimatosas/metabolismo , PoloxámeroRESUMEN
Both O-linked ß-N-acetylglucosaminylation (O-GlcNAcylation) and endoplasmic reticulum-phagy (ER-phagy) are well-characterized conserved adaptive regulatory mechanisms that maintain cellular homeostasis and function in response to various stress conditions. Abnormalities in O-GlcNAcylation and ER-phagy have been documented in a wide variety of human pathologies. However, whether O-GlcNAcylation or ER-phagy is involved in the pathogenesis of intervertebral disc degeneration (IDD) is largely unknown. In this study, we investigated the function of O-GlcNAcylation and ER-phagy and the related underlying mechanisms in IDD. We found that the expression profiles of O-GlcNAcylation and O-GlcNAc transferase (OGT) were notably increased in degenerated NP tissues and nutrient-deprived nucleus pulposus (NP) cells. By modulating the O-GlcNAc level through genetic manipulation and specific pharmacological intervention, we revealed that increasing O-GlcNAcylation abundance substantially enhanced cell function and facilitated cell survival under nutrient deprivation (ND) conditions. Moreover, FAM134B-mediated ER-phagy activation was regulated by O-GlcNAcylation, and suppression of ER-phagy by FAM134B knockdown considerably counteracted the protective effects of amplified O-GlcNAcylation. Mechanistically, FAM134B was determined to be a potential target of OGT, and O-GlcNAcylation of FAM134B notably reduced FAM134B ubiquitination-mediated degradation. Correspondingly, the protection conferred by modulating O-GlcNAcylation homeostasis was verified in a rat IDD model. Our data demonstrated that OGT directly associates with and stabilizes FAM134B and subsequently enhances FAM134B-mediated ER-phagy to enhance the adaptive capability of cells in response to nutrient deficiency. These findings may provide a new option for O-GlcNAcylation-based therapeutics in IDD prevention.
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Degeneración del Disco Intervertebral , Animales , Autofagia , Retículo Endoplásmico/metabolismo , Humanos , Degeneración del Disco Intervertebral/genética , Degeneración del Disco Intervertebral/metabolismo , N-Acetilglucosaminiltransferasas/genética , N-Acetilglucosaminiltransferasas/metabolismo , RatasRESUMEN
Mesenchymal stem cells (MSCs) are ideal candidates for tissue engineering and regenerative medicine because of their proliferative capacity and differentiation potential. However, the hypertrophic phenotype occurring in late MSCs chondrogenic differentiation severely limits their clinical translation. While hypertrophy inhibition strategies have been explored, the role of cell metabolism in MSCs chondrogenesis has rarely been studied. In this study, we found that hypertrophy occurred in the late stage of MSCs chondrogenesis with increased fatty acid oxidation (FAO) and decreased glycolysis, as well as cell-cell junctions impairment. Therefore, a N-cadherin mimetic hydrogel was developed to enhance cell-cell junctions via N-cadherin mimetic peptides and high seeding density. The N-cadherin mimetic hydrogel attenuated hypertrophy through regulating glycolysis and FAO. The regulation of cell-cell junctions mechanotransduction on cell metabolism was partly mediated by Hif-1α. In addition, 2D and 3D culture of N-cadherin mimetic hydrogel had similar functions on N-cadherin expression and chondrogenesis in MSCs. Our study is the first to reveal that metabolic remodeling induced hypertrophy during MSCs chondrogenesis, and indicate the effect of N-cadherin mimetic hydrogel on hypertrophy inhibition of MSCs. STATEMENT OF SIGNIFICANCE: The development of hypertrophy during MSCs chondrogenesis severely limits its clinical translation. Various strategies have been explored to inhibit hypertrophy by chemical and/or mechanical stimulation. However, the role of cell metabolism in MSCs chondrogenesis has rarely been studied. In this study, we developed an RNA sequencing at day 0, 7, and 21 of MSCs chondrogenesis to clarify the mechanisms that mediate hypertrophy. We found that hypertrophy occurred in the late stage of MSCs chondrogenesis with increased FAO and decreased glycolysis, as well as impaired cell-cell junctions. We also found that N-cadherin mimetic hydrogel attenuated hypertrophy and enhanced chondrogenesis through regulating glycolysis and FAO. Our finding provides new insights into the application of MSCs in tissue engineering and regenerative medicine.
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Condrogénesis , Hidrogeles , Cadherinas/farmacología , Diferenciación Celular , Células Cultivadas , Humanos , Hidrogeles/farmacología , Hipertrofia , Mecanotransducción CelularRESUMEN
Accumulating evidence indicates that ER-phagy serves as a key adaptive regulatory mechanism in response to various stress conditions. However, the exact mechanisms underlying ER-phagy in the pathogenesis of intervertebral disc degeneration remain largely unclear. In the present study, we demonstrated that RETREG1-mediated ER-phagy is induced by glucose deprivation (GD) treatment, along with ER stress activation and cell function decline. Importantly, ER-phagy was shown to be crucial for cell survival under GD conditions. Furthermore, ER stress was suggested as an upstream event of ER-phagy upon GD treatment and upregulation of ER-phagy could counteract the ER stress response. Therefore, our findings indicate that RETREG1-mediated ER-phagy activation protects against GD treatment-induced cell injury via modulating ER stress in human nucleus pulposus cells.
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Degeneración del Disco Intervertebral , Núcleo Pulposo , Apoptosis , Autofagia/fisiología , Retículo Endoplásmico/metabolismo , Estrés del Retículo Endoplásmico , Glucosa/metabolismo , Humanos , Degeneración del Disco Intervertebral/patología , Núcleo Pulposo/patologíaRESUMEN
Nanotopographical cues endow biomaterials the ability to guide cell adhesion, proliferation, and differentiation. Cellular mechanical memory can maintain the cell status by retaining cellular information obtained from past mechanical microenvironments. Here, we propose a new concept "morphology memory of small extracellular vesicles (sEV)" for bone regeneration. We performed nanotopography on titanium plates through alkali and heat (Ti8) treatment to promote human mesenchymal stem cell (hMSC) differentiation. Next, we extracted the sEVs from the hMSC, which were cultured on the nanotopographical Ti plates for 21 days (Ti8-21-sEV). We demonstrated that Ti8-21-sEV had superior pro-osteogenesis ability in vitro and in vivo. RNA sequencing further confirmed that Ti8-21-sEV promote bone regeneration through osteogenic-related pathways, including the PI3K-AKT signaling pathway, MAPK signaling pathway, focal adhesion, and extracellular matrix-receptor interaction. Finally, we decorated the Ti8-21-sEV on a 3D printed porous polyetheretherketone scaffold. The femoral condyle defect model of rabbits was used to demonstrate that Ti8-21-sEV had the best bone ingrowth. In summary, our study demonstrated that the Ti8-21-sEV have memory function by copying the pro-osteogenesis information from the nanotopography. We expect that our study will encourage the discovery of other sEV with morphology memory for tissue regeneration.
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BACKGROUND: The intervertebral disc (IVD) degeneration is the leading cause of low back pain, which accounts for a main cause of disability. N6-methyladenosine (m6A) is the most abundant internal modification in eukaryotic messenger RNAs and is involved in various diseases and cellular processes by modulating mRNA fate. However, the critical role of m6A regulation in IVD degeneration remains unclear. Nucleus pulposus cell (NPC) senescence is critical for the progression of IVD degeneration. Here, we uncovered the role and explored the regulatory mechanism of m6A in NPC senescence during IVD degeneration. METHODS: Identification of NPC senescence during IVD degeneration was based on the analysis of tissue samples and the cellular model. ALKBH5 upregulation inducing cellular senescence was confirmed by functional experiments in vivo and in vitro. ChIP-qPCR and DNA-Pulldown were used to reveal increased ALKBH5 was regulated by KDM4A-mediated H3K9me3. Furthermore, Me-RIP-seq was performed to identify m6A hypomethylation of DNMT3B transcripts in senescent NPCs. Stability analysis showed that DNMT3B expression was enhanced for less YTHDF2 recognition and increased DNMT3B promoted NPC senescence and IVD degeneration via E4F1 methylation by in vivo and in vitro analyses. RESULTS: Expression of ALKBH5 is enhanced during IVD degeneration and NPC senescence, due to decreased KDM4A-mediated H3K9me3 modification. Functionally, ALKBH5 causes NPC senescence by demethylating DNMT3B transcripts and in turn promoting its expression via less YTHDF2 recognition and following degradation due to transcript hypomethylation in vitro and in vivo. Increased DNMT3B promotes the development of IVD degeneration and NPC senescence, mechanistically by methylating CpG islands of E4F1 at the promoter region and thus restraining its transcription and expression. CONCLUSIONS: Collectively, our findings reveal an epigenetic interplay mechanism in NPC senescence and IVD degeneration, presenting a critical pro-senescence role of ALKBH5 and m6A hypomethylation, highlighting the therapeutic potential of targeting the m6A/DNMT3B/E4F1 axis for treating IVD degeneration.
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Degeneración del Disco Intervertebral , Núcleo Pulposo , Desmetilasa de ARN, Homólogo 5 de AlkB/genética , Desmetilasa de ARN, Homólogo 5 de AlkB/metabolismo , Senescencia Celular/genética , Metilación de ADN/genética , Humanos , Degeneración del Disco Intervertebral/genética , Degeneración del Disco Intervertebral/metabolismo , Histona Demetilasas con Dominio de Jumonji/genética , Histona Demetilasas con Dominio de Jumonji/metabolismo , Núcleo Pulposo/metabolismo , ARN Mensajero/genética , Proteínas Represoras/genética , Proteínas Represoras/metabolismo , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
N6-methyladenosine (m6A) is the most prevalent RNA modification at the posttranscriptional level and involved in various diseases and cellular processes. However, the underlying mechanism of m6A regulation in intervertebral disc degeneration (IVDD) remains elusive. Here, we show that methylation of the lncRNA NORAD significantly increases in senescent nucleus pulposus cells (NPCs) by m6A sequencing. Subsequent loss- and gain-of-function experiments reveal WTAP is increased in senescent NPCs due to an epigenetic increase in H3K4me3 of the promoter mediated by KDM5a, and significantly promotes NORAD m6A modification. Furthermore, YTHDF2-mediated decay of NORAD is enhanced in senescent NPCs, and then deficiency of NORAD results in less sequestraion of PUMILIO proteins, contributing to the augmented activity of PUM1/2, thus repressing the expression of target E2F3 mRNAs and promoting the cellular senescence. Here, we show interruption of NORAD m6A modification or the NORAD/PUMILIO/E2F3 axis could serve as a potential therapeutic target to inhibit the senescence of NPCs and development of IVDD.
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Degeneración del Disco Intervertebral , Disco Intervertebral , Núcleo Pulposo , ARN Largo no Codificante , Proteínas de Ciclo Celular/metabolismo , Senescencia Celular/genética , Humanos , Disco Intervertebral/metabolismo , Degeneración del Disco Intervertebral/metabolismo , Núcleo Pulposo/metabolismo , Factores de Empalme de ARN/metabolismo , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , ARN Mensajero/metabolismo , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Proteína 2 de Unión a Retinoblastoma/metabolismoRESUMEN
Low back pain (LBP) is a major musculoskeletal disorder and the socioeconomic problem with a high prevalence that mainly involves intervertebral disc (IVD) degeneration, characterized by progressive nucleus pulposus (NP) cell death and the development of an inflammatory microenvironment in NP tissue. Excessively accumulated cytosolic DNA acts as a damage-associated molecular pattern (DAMP) that is monitored by the cGAS-STING axis to trigger the immune response in many degenerative diseases. NLRP3 inflammasome-dependent pyroptosis is a type of inflammatory programmed death that promotes a chronic inflammatory response and tissue degeneration. However, the relationship between the cGAS-STING axis and NLRP3 inflammasome-induced pyroptosis in the pathogenesis of IVD degeneration remains unclear. Here, we used magnetic resonance imaging (MRI) and histopathology to demonstrate that cGAS, STING, and NLRP3 are associated with the degree of IVD degeneration. Oxidative stress induced cGAS-STING axis activation and NLRP3 inflammasome-mediated pyroptosis in a STING-dependent manner in human NP cells. Interestingly, the canonical morphological and functional characteristics of mitochondrial permeability transition pore (mPTP) opening with the cytosolic escape of mitochondrial DNA (mtDNA) were observed in human NP cells under oxidative stress. Furthermore, the administration of a specific pharmacological inhibitor of mPTP and self-mtDNA cytosolic leakage effectively reduced NLRP3 inflammasome-mediated pyroptotic NP cell death and microenvironmental inflammation in vitro and degenerative progression in a rat disc needle puncture model. Collectively, these data highlight the critical roles of the cGAS-STING-NLRP3 axis and pyroptosis in the progression of IVD degeneration and provide promising therapeutic approaches for discogenic LBP.
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Degeneración del Disco Intervertebral , Núcleo Pulposo , Animales , ADN Mitocondrial/genética , ADN Mitocondrial/metabolismo , ADN Mitocondrial/farmacología , Inflamasomas/metabolismo , Inflamación/metabolismo , Degeneración del Disco Intervertebral/metabolismo , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Nucleotidiltransferasas/genética , Nucleotidiltransferasas/metabolismo , Núcleo Pulposo/metabolismo , Piroptosis , RatasRESUMEN
Engineered small extracellular vesicles (sEVs) are used as tools to enhance therapeutic efficacy. However, such application of sEVs is associated with several issues, including high costs and a high risk of tumorigenesis. Nanotopography has a greater influence on bone-related cell behaviors. However, whether nanotopography specifically mediate sEV content to perform particular biological functions remains unclear. Here, we demonstrate that selective nanotopography may be used to sequentially mediate human bone mesenchymal stem cell (hBMSC) sEVs to enhance the therapeutic efficacy of hBMSCs-EVs for osteogenesis. We subjected sEVs harvested from hBMSCs cultured on polished titanium plates (Ti) or nanotopographical titanium plates (Ti4) after 7, 14, and 21 d for RNA sequencing, and we found that there was no significant difference in sEV-miRNA expression after 7 d. Differentially expressed osteogenic-related microRNAs were founded after 14 days, and KEGG analysis indicated that the main microRNAs were associated with osteogenesis-related pathways, such as TGF-beta, AMPK, and FoxO. A significant difference was found in sEV-miRNAs expression after 21 d. We loaded sEV secreted from hBMSCs cultured on Ti4 after 21 d on 3D-printed porous PEEK scaffolds with poly dopamine (PDA) and found that such scaffolds showed superior osteogenic ability after 6- and 12-weeks. Here, we demonstrate the alkali- and heat-treated nanotopography with the ability of stimulating osteogenic differentiation of hBMSC can induce the secretion of pro-osteogenesis sEV, and we also found that sEVs meditate osteogenesis through miRNA. Thus, whether nanotopography has the ability to regulate other contents of sEVs such as proteins for enhancing osteogenesis needs further research. These findings may help us use nanotopography to extract sEVs for other biomedical applications, including cancer therapy.
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Vesículas Extracelulares , Células Madre Mesenquimatosas , MicroARNs , Humanos , Osteogénesis/fisiología , Titanio/farmacología , Titanio/metabolismo , Vesículas Extracelulares/metabolismo , Diferenciación Celular/fisiología , MicroARNs/metabolismoRESUMEN
The death of nucleus pulposus (NP) cells is an important cause of intervertebral disc (IVD) degeneration. Redox disturbance caused by dysfunctional mitochondria has been considered as a vital risk for NP cell survival. It is valuable to identify key proteins maintaining mitochondrial function in NP cells. A previous study found that regulated in development and DNA damage response 1 (REDD1) are upregulated during intervertebral disc degeneration and that REDD1 can cause NP cell apoptosis. Thus, the present study further explores the effect of REDD1 on IVD degeneration. Our results showed that REDD1 promotes NP cell apoptosis via the mitochondrial pathway. Importantly, REDD1 formed a complex with TXNIP to strengthen its own action, and the combination was consolidated under H2O2-induced oxidative stress. The combined inhibition of the REDD1/TXNIP complex was better than that of REDD1 or TXNIP alone in restoring cell proliferation and accelerating apoptosis. Moreover, p53 acts as the transcription factor of REDD1 to regulate the REDD1/TXNIP complex under oxidative stress. Altogether, our results demonstrated that the REDD1/TXNIP complex mediated H2O2-induced human NP cell apoptosis and IVD degeneration through the mitochondrial pathway. Interferences on these sites to achieve mitochondrial redox homeostasis may be a novel therapeutic strategy for oxidative stress-associated IVD degeneration.
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Apoptosis , Proteínas Portadoras/metabolismo , Mitocondrias/metabolismo , Estrés Oxidativo , Factores de Transcripción/metabolismo , Adolescente , Adulto , Proteínas Portadoras/antagonistas & inhibidores , Proteínas Portadoras/genética , Supervivencia Celular/efectos de los fármacos , Femenino , Humanos , Peróxido de Hidrógeno/farmacología , Degeneración del Disco Intervertebral/metabolismo , Degeneración del Disco Intervertebral/patología , Masculino , Persona de Mediana Edad , Mitocondrias/efectos de los fármacos , Núcleo Pulposo/citología , Núcleo Pulposo/metabolismo , Estrés Oxidativo/efectos de los fármacos , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Factores de Transcripción/antagonistas & inhibidores , Factores de Transcripción/genética , Proteína p53 Supresora de Tumor/metabolismo , Adulto JovenRESUMEN
Symptomatic adjacent segment disease (ASD) is a common challenge after anterior cervical discectomy and fusion (ACDF). The objective of this study was to compare the biomechanical effects of a second ACDF and laminoplasty for the treatment of ASD after primary ACDF. We developed a finite element (FE) model of the C2-T1 based on computed tomography images. The FE models of revision surgeries of ACDF and laminoplasty were simulated to treat one-level and two-level ASD after primary ACDF. The range of motion (ROM) and intradiscal pressure (IDP) of the adjacent segments, and stress in the cord were analyzed to investigate the biomechanical effects of the second ACDF and laminoplasty. The results indicated that revision surgery of one-level ACDF increased the ROM and IDP at the C2-C3 segment, whereas two-level ACDF significantly increased the ROM and IDP at the C2-C3 and C7-T1 segments. Furthermore, no significant changes in the ROM and IDP of the laminoplasty models were observed. The stress in the cord of the re-laminoplasty model decreased to some extent, which was higher than that of the re-ACDF model. In conclusion, both ACDF and laminoplasty can relieve the high level of stress in the spinal cord caused by ASD after primary ACDF, whereas ACDF can achieve better decompression effect. Revision surgery of the superior ACDF or the superior and inferior ACDF after the primary ACDF increased the ROM and IDP at the adjacent segments, which may be the reason for the high incidence of recurrent ASD after second ACDF.
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Previous studies have established the pathogenic role of advanced glycation end products (AGEs) accumulation in intervertebral disc degeneration (IDD). Emerging evidence indicates that ER-phagy serves as a crucial cellular adaptive mechanism during stress conditions. This study is aimed at investigating the role of FAM134B-mediated ER-phagy in human nucleus pulposus (NP) cells upon AGEs treatment and exploring its regulatory mechanisms. We observed that AGEs treatment resulted in significantly increased apoptosis, senescence, and ROS accumulation in human NP cells; meanwhile, the enhanced apoptosis and senescence by AGEs treatment could be partially alleviated with the classic ROS scavenger NAC administration. Furthermore, we confirmed that FAM134B-mediated ER-phagy was activated under AGEs stimulation via ROS pathway. Importantly, it was also found that FAM134B overexpression could efficiently relieve intracellular ROS accumulation, apoptosis, and senescence upon AGEs treatment; conversely, FAM134B knockdown markedly resulted in opposite effects. In conclusion, our data demonstrate that FAM134B-mediated ER-phagy plays a vital role in AGEs-induced apoptosis and senescence through modulating cellular ROS accumulation, and targeting FAM134B-mediated ER-phagy could be a promising therapeutic strategy for IDD treatment.
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Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Senescencia Celular/efectos de los fármacos , Productos Finales de Glicación Avanzada/farmacología , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas de la Membrana/metabolismo , Células Cultivadas , Productos Finales de Glicación Avanzada/metabolismo , Humanos , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Péptidos y Proteínas de Señalización Intracelular/genética , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/genética , Núcleo Pulposo/citología , Núcleo Pulposo/metabolismo , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Regulación hacia ArribaRESUMEN
Stem cell senescence contributes to stem cell exhaustion and drives various aging-associated disorders. However, strategies to rejuvenate senescent stem cells are limited. The present study proposes an approach based on triboelectric stimulation to rejuvenate senescent bone marrow mesenchymal stromal cells (BMSCs) by fabricating a pulsed triboelectric nanogenerator (P-TENG) that can produce stable pulsed current output unaffected by the triggered frequency. The senescence phenotypes of aged BMSCs are reversed by triboelectric stimulation at 30 µA at 1.5 Hz. Triboelectric stimulation enhances the proliferation of aged BMSCs and increases their pluripotency and differentiation capacity. Additionally, mechanistic investigations reveal that pulsed triboelectric stimulation by P-TENG rejuvenates senescent BMSCs by enhancing MDM2-dependent p53 degradation, which is demonstrated by loss-of-function studies of MDM2 and p53. Overall, this study identifies a new approach for the rejuvenation of senescent BMSCs and describes a promising therapeutic intervention for many diseases associated with aged BMSCs.
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Envejecimiento/fisiología , Senescencia Celular/fisiología , Estimulación Eléctrica/métodos , Células Madre Mesenquimatosas/fisiología , Rejuvenecimiento/fisiología , Adulto , Anciano , Animales , Diferenciación Celular , Femenino , Humanos , Masculino , Modelos Animales , Osteogénesis , Ratas , Ratas Sprague-Dawley , Adulto JovenRESUMEN
Intervertebral disc degeneration (IDD) is a common and early-onset pathogenesis in the human lifespan that can increase the risk of low back pain. More clarification of the molecular mechanisms associated with the onset and progression of IDD is likely to help establish novel preventive and therapeutic strategies. Recently, mitochondria have been increasingly recognized as participants in regulating glycolytic metabolism, which has historically been regarded as the main metabolic pathway in intervertebral discs due to their avascular properties. Indeed, mitochondrial structural and functional disruption has been observed in degenerated nucleus pulposus (NP) cells and intervertebral discs. Multilevel and well-orchestrated strategies, namely, mitochondrial quality control (MQC), are involved in the maintenance of mitochondrial integrity, mitochondrial proteostasis, the mitochondrial antioxidant system, mitochondrial dynamics, mitophagy, and mitochondrial biogenesis. Here, we address the key evidence and current knowledge of the role of mitochondrial function in the IDD process and consider how MQC strategies contribute to the protective and detrimental properties of mitochondria in NP cell function. The relevant potential therapeutic treatments targeting MQC for IDD intervention are also summarized. Further clarification of the functional and synergistic mechanisms among MQC mechanisms may provide useful clues for use in developing novel IDD treatments.
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Degeneración del Disco Intervertebral/etiología , Mitocondrias/metabolismo , Núcleo Pulposo/metabolismo , Animales , Humanos , Mitocondrias/patología , Mitofagia/fisiología , Núcleo Pulposo/patologíaRESUMEN
Intervertebral disc degeneration (IDD) is the primary cause of low back pain. Stress-induced DNA damage is closely relevant to the pathogenesis of IDD; however, the underlying mechanisms remain unclear. This study investigated the role of the absent in melanoma 2 (AIM2) inflammasome as a DNA damage sensor in nucleus pulposus (NP) cells. We found that the level of AIM2 increased in degenerated discs and was correlated to the degree of IDD. Knockdown of AIM2 ameliorated H2O2-induced DNA damage and apoptosis in NP cells in vitro, and retarded the progression of IDD in vivo. Furthermore, the induction of autophagy protected against cellular DNA damage via the unconventional secretion of AIM2. We further identified the Golgi re-assembly and stacking protein 55 (GRASP55) as mediator of the transport and secretion of AIM2 via an autophagic pathway. Taken together, our researches illustrate the role and regulatory mechanism of the AIM2 inflammasome during IDD. Targeting the AIM2 inflammasome may offer a promising therapeutic strategy for patients with IDD.
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Extracellular vesicles (EVs) are extracellular nanovesicles that deliver diverse cargoes to the cell and participate in cell communication. Mesenchymal stem cell (MSCs)-derived EVs are considered a therapeutic approach in musculoskeletal degenerative diseases, including intervertebral disc degeneration. However, limited production yield and unstable quality have impeded the clinical application of EVs. In the present study, it is indicated that metformin promotes EVs release and alters the protein profile of EVs. Metformin enhances EVs production via an autophagy-related pathway, concomitantly with the phosphorylation of synaptosome-associated protein 29. More than quantity, quality of MSCs-derived EVs is influenced by metformin treatment. Proteomics analysis reveals that metformin increases the protein content of EVs involved in cell growth. It is shown that EVs derived from metformin-treated MSCs ameliorate intervertebral disc cells senescence in vitro and in vivo. Collectively, these findings demonstrate the great promise of metformin in EVs-based intervertebral disc regeneration.