N6-methyladenosine circRNA Epitranscriptomic Microarray of human nucleus pulposus in intervertebral disc degeneration
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ABSTRACT: It is well documented that low back pain is a common condition and the leading cause of disability globally. A widely recognised contributor to low back pain is intervertebral disc degeneration (IVDD), which is the major cause of a series of degenerative disc diseases. Recently, it has been reported that circRNAs are involved in the development of IVDD. However, the mechanisms by which m6A modifies circRNA in nucleus pulposus cells remain poorly understood. Here, we aim to identify differentially expressed m6A circRNAs in degenerative nucleus pulposus cells and figure out how the circRNAs regulate IVDD progression and the m6A methylation functions.
Project description:Failure of intervertebral disc components, e.g. the nucleus pulposus causes intervertebral disc disease and associated low-back pain. Despite the high prevalence of disc disease, the changes in intervertebral disc cells and their regenerative potential with ageing and degeneration are not fully elucidated. Understanding the cell lineage, cell differentiation and maintenance of nucleus pulposus may have therapeutic application for the regeneration of degenerative disc, with significant impact for healthy ageing. Here we found that TAGLN expressing cells are present in human healthy nucleus pulposus, but diminish in degenerative disc. By lineage analyses in mice, we found cells in the nucleus pulposus are derived from a peripherally located population of notochord-derived Tagln expressing cells (PeriNP cells). The PeriNP cells are proliferative and can differentiate into the inner part of the nucleus pulposus. The Tagln+ cells and descendants diminish during aging and puncture induced disc degeneration. The maintenance and differentiation of PeriNP cells is partially regulated by Smad4 dependent signaling. Removal of Smad4 by nucleus pulposus specific Cre (Foxa2mNE-Cre), results in decreased Tagln+ cells and abnormal disc morphology, leading to disc degeneration. Our findings propose that the PeriNP Tagln expressing cells are a pool of notochord-derived progenitors that are important for maintenance of the nucleus pulposus and provide insights for regenerative therapy against intervertebral disc degeneration.
Project description:Given the leading cause of disability worldwide, low back pain (LBP) is recognized as a pivotal socio-economic challenge to the aging population, which is importantly attributed to intervertebral disc degeneration (IVDD), a highly prevalent affliction of aging. Elastic nucleus pulposus (NP) tissue is essential for maintenance of IVD structural and functional integrity. Native NP cells exhibit crucial functions for regulating extracellular matrix homeostasis, constructing an accommodating biomechanical environment and maintaining the gelatinous property of NP tissue. Mechanical stresses, including compulsion position and aberrant mechanical loading, are regarded as etiological factors of IVDD, and to further investigate the effect of mechanical exercise during the degeneration of IVDs, we surgically resected the lumbar 4th-lumbar 5th (L4-L5) spinous processes of the rat spine along with the supraspinous and interspinous ligaments to induce lumbar surgical instability (LSI). Additionally, we applied RNA sequencing technology to describe the degeneration-associated molecular atlas of the LSI model during exercise, and found that exercise accelerated the degenerative process of IVDs from LSI, which is involved in cytosolic DNA sensing-mediated inflammatory activation, similar to the degenerative patterns of the clinical IVDD process.
Project description:In this study, to explore the potential involvement of m6A modification in intervertebral disc degeneration, we conducted RNA m6A modification profiling in 3 human control nucleus pulposus tissue and 3 degenerative nucleus pulposus tissue by m6A-RIP-sequencing.
Project description:Intervertebral disc degeneration (IVDD) is a main cause of degenerative disc disease, which results in substantial pain among patients. However, the mechanism of degeneration remains unclear. Thus far, basic research on human IVDD has focused on only a limited number of proteins and has not been conducted from a holistic perspective. In this study, we used tandem mass tag (TMT) labeling combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) to perform differential proteomic analysis on fetal and geriatric lumbar disc nucleus pulposus tissue. These data indicate that differential proteomics analysis may be an important method for elucidation of the pathophysiological process and molecular biological mechanism of human IVDD from a holistic perspective. The findings in this study will aid in screening of new biomarkers for early diagnosis and targeted treatment of IVDD.
Project description:Low back pain is a major cause of disability especially for people between 20 and 50 years of age. As a costly healthcare problem, it imposes a serious socio-economic burden. Current surgical therapies have considerable drawbacks and fail to replace the normal disc in facilitating spinal movements and absorbing load. Therefore, the focus of regenerative medicine is on identifying biomarkers and signalling pathways to improve our understanding about the cascades of disc degeneration and allow for the design of specific therapies. We hypothesized that comparing microarray profiles from degenerative and non-degenerative discs will lead to the identification of dysregulated signalling and pathophysiological targets. Microarray data sets were generated from human annulus fibrosus cells and analysed using IPA ingenuity pathway analysis system. Gene expression values were validated by qRT-PCR, and respective proteins were identified by immunohistochemistry. Microarray analysis revealed 17 dysregulated molecular markers and various dysregulated cellular functions, including cell proliferation and inflammatory response, in the human degenerative annulus fibrosus. The most significant canonical pathway induced in degenerative annulus fibrosus was found to be the interferon signalling pathway. In conclusion, this study indicates interferon-alpha signalling pathway activation with IFIT3 and IGFBP3 up-regulation which may affect cellular function in human degenerative disc. 48 samples of intervertebral disc tissue - annulus fibrosus and nucleus pulposus - displaying varying degrees (grades) of degeneration
Project description:Low back pain (LBP) is one of the most common musculoskeletal disorders with a huge global impact. Intervertebral disc degeneration (IVDD) is an important cause of low back pain. Therefore, it is crucial to identify and elucidate the key factors affecting IVDD. We identified CRLF1, a key molecule in the process of IVDD, by Gene Expression Omnibus dataset, and determined the high expression of CRLF1 within the degenerated discs and in senescent NPCs by IHC, WB. To further explore the effect of CRLF1 on NPCs, we applied RNA-seq to explore the phenotypic changes of NPCs treated with CRLF1.
Project description:Circular RNA expression profiling of human nucleus pulposus derived from patients with IDD in comparison with those derived from cadaveric disc as normal control. We have identified the expression profiles of miRNAs (GSE63492), lncRNAs, mRNAs (GSE56081) in IDD using 5 normal discs as control and 5 IDD discs. Accumulating evidence indicates that circRNAs are key regulators of gene expression by interacting with miRNAs. circRNA is a novel type of RNA that, unlike linear RNA, forms a covalently closed continuous loop, and is highly represented in the eukaryotic transcriptome. Two-condition experiment: control nucleus pulposus vs. degenerative nucleus pulposus. Biological replicates: 5 control, 5 degenerated, independently harvested (the same samples as GSE56081 and GSE63492). Four replicates per array.
Project description:Intervertebral disc degeneration is the main cause of low back pain and the mechanism of which is far from fully revealed. Although multiple factors are related to the intervertebral disc degeneration, inflammation and matrix metabolism dysregulation are the two key factors that play an important role in degeneration. Here, we found that inflammation-related factor CHI3L1 is highly regulated in the nucleus pulposus during degeneration in both RNA and protein level. Immunohistochemical analysis show that the expression of CHI3L1 are NP tissue specific, and increased significantly in the degenerated nucleus pulposus cells. The mechanism of CHI3L1 is thus studied in this experiment.
Project description:Given the leading cause of disability worldwide, low back pain (LBP) is recognized as a pivotal socio-economic challenge to the aging population, which is importantly attributed to intervertebral disc degeneration (IVDD), a highly prevalent affliction of aging. Elastic nucleus pulposus (NP) tissue is essential for maintenance of IVD structural and functional integrity. Native NP cells exhibit crucial functions for regulating extracellular matrix homeostasis, constructing an accommodating biomechanical environment and maintaining the gelatinous property of NP tissue. The accumulation of senescent NP cells with inflammatory hypersecretory phenotype due to aging and other damaged factors is a distinctive hallmark of IVDD initiation and progression. In this study, we revealed a mechanism of IVDD progression in which aberrant genomic DNA damage promotes NP cell inflammatory senescence via activation of cGAS-STING axis. cGAS-STING axis activation drove inflammatory phenotype acquisition and inflammatory hypersensitivity to damaged signals of senescent NP cells via p65-mediated transcriptional modulation. And STING pharmacological inhibitor notably suppressed p65-mediated inflammatory response formation and senescence-associated screctory phenotype (SASP) acquisition of senescent cells.
Project description:Nucleus pulposus (NP) plays a vital role in intervertebral disc degeneration (IVDD). Previous studies have revealed cellular heterogeneity in the NP tissue during IVDD progression. Here, we used single cell RNA sequencing (scRNA-seq) to analyze the cellular and molecular alterations of diverse cell clusters during IVDD.