Increased HIF-2α Activity in the Nucleus Pulposus Causes Mild Degenerative Changes in the Intervertebral Disc in the Aging Mouse Spine
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE249908 | GEO | 2024/03/27
REPOSITORIES: GEO
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Project description:Gene expression profiling of primary mouse articular chondrocyte infected with recombinant adenovirus expressing the hypoxia inducible factor-2 alpha (HIF-2α) protein. In this study, we have attempted to explore the effects of HIF-2α overexpression on mouse transcriptome and have identified numerous genes which are involved in osteoarthritis pathogenesis.
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Project description:Background: The nucleus pulposus is a constituent structure of the human intervertebral disc, and its degeneration can cause Intervertebral disc degeneration (IDD). However the cellular molecular mechanisms involved remain elusive. Methods: Through bioinformatics analysis, the single-cell transcriptome sequencing expression profiles of human normal nucleus pulposus cells (NNP) and human degenerative nucleus pulposus cells (DNP) were compared to clarify the transcriptome differential expression profiles of human normal and human degenerative nucleus pulposus cells. The single-cell sequencing results of the two samples were analyzed using bioinformatics methods to compare the differences in histiocytosis between human normal nucleus pulposus and human degenerated nucleus pulposus, map the histiocytes of NNP and DNP, perform cell differentiation trajectories for the cell populations of interest and predict cell function, and explore their heterogeneity by pathway analysis and Gene ontology analysis. Results: Nine cell types were identified, which were Chondrocyte1, Chondrocyte2, Chondrocyte3, Chondrocyte4, Chondrocyte5, Endothelial, Macrophage, Neutrophil, and T cells. Analysis of the proportion of chondrocytes in different tissues revealed that chondrocyte 1 accounted for a higher proportion of normal nucleus pulposus cells and highly expressed COL2A1 compared with degenerated nucleus pulposus cells; chondrocyte 2, chondrocyte 3, chondrocyte 4, and chondrocyte 5 accounted for a higher proportion of degenerated nucleus pulposus cells compared with normal nucleus pulposus cells. Among them, chondrocyte 2 was an inhibitory calcified chondrocyte with high expression of MGP, Chondrocytes 3 were fibrochondrocytes with high expression of COL1A1, Chondrocytes 4 are chondrocytes that highly express pain inflammatory genes such as PTGES, Chondrocytes 5 were calcified chondrocytes with high expression of FN1. (Chondrocytes 4 and chondrocytes 5 were found for the first time in a study of single-cell transcriptome sequencing of disc tissue.) Cell trajectory analysis revealed that chondrocyte 1 was at the beginning of the trajectory and chondrocyte 3 was at the end of the trajectory, while chondrocyte 5 appeared first in the trajectory relative to chondrocyte 2 and chondrocyte 4. Conclusion: After functional identification of the specifically expressed genes in five chondrocytes, it was found that chondrocyte 1 was a chondrocyte with high expression of COL2A1, COL9A2, COL11A2, and CHRDL2 in a high proportion of normal nucleus pulposus cells, and chondrocyte 3 was a fibrochondrocyte with high expression of COL1A1, COL6A3, COL1A2, COL3A1, AQP1, and COL15A1 in an increased proportion during nucleus pulposus cell degeneration. Through cell trajectory analysis, it was found that chondrocytes 5 specifically expressing FN1, SESN2, and GDF15 may be the key cells leading to degeneration of nucleus pulposus cells. Chondrocytes 2 expressing MGP, MT1G, and GPX3 may play a role in reversing calcification and degeneration, and chondrocytes 4 expressing PTGES, TREM1, and TIMP1 may play a role in disc degeneration pain and inflammation.
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Project description:Chronic hypoxia induces pulmonary vascular remodeling and pulmonary hypertension (PH). While it is established that transcription factors, hypoxia-inducible factors (HIF-1α/HIF-2α) activate gene programs that drive hypoxia-induced PH, the mechanism of HIF-1/2 activation is less clear. Here, we report that carboxylterminus of Hsp70-interacting protein (CHIP or Stub1) modulates HIF-1α and HIF-2α transcription rather than reducing their stability. Knocking-down Stub1 reduced hypoxic activation of HIF-1α mRNA, protein, and activity while enhancing hypoxic induction of HIF-2α mRNA, protein, and target genes in pulmonary vascular cells. Mechanistically, CBP/p300-mediated acetylation of lysine (K287) inactivates the ubiquitin ligase activity of Stub1 and triggers its translocation from the cytoplasm into the nucleus. There, it recognizes the HIF promoter and hypoxia response elements (HREs) in target genes. Expression of Stub1-K287Q mutant (mimicking acetylation) enhanced hypoxia-induced HIF-1α expression, while acetyl-deficient Stub1-K287R mutant had the opposite effect on HIF-α but enhanced hypoxia-induced HIF-2α transcriptional activity. Endothelial-Stub1 transgenic mice tolerated chronic hypoxia better, had less pulmonary vascular remodeling, reduced pulmonary vascular resistance, and greater cardioprotection. Thus, Stub1 nuclear translocation enhances hypoxic induction of HIF-1α activity while suppressing deleterious effects of HIF-2α. These observations indicate that nuclear-Stub1 synergizes with HIF-1α to promote transcriptional responses and antagonizes HIF2α-driven PH in chronic hypoxia.
2023-04-01 | GSE221264 | GEO
Project description:Synovial and bone marrow mesenchymal stem cells after intradiscally injection show regenerative effects of nucleus pulposus. Microarray analyses of rats were performed to investigate the closeness of the gene profiles between the nucleus pulposus cells and the synovial or bone marrow mesenchymal stem cells. To investigate interaction between synovial mesenchymal stem cells and nucleus pulposus cells, human synovial mesenchymal stem cells and rat nucleus pulposus cells were co-cultured, and species specific microarray were performed. Synovium of knee joints, bone marrow and nucleus pulposus were harvested from rat or human, and cells were isolated for RNA extraction and hybridization on Affymetrix microarrays. To compare the gene profiles each other, isolated cells were mono-cultured respectively, and human synovial mesenchymal stem cells and rat nucleus pulposus cells were co-cultured.
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Project description:MicroRNAs expression profiling of human nucleus pulposus cells derived from patients with disc degeneration in comparison with those derived from patients with scoliosis as control. Two-condition experiment: control nucleus pulposus cells vs. degenerative nucleus pulposus cells. Biological replicates: 3 control, 3 degenerated, independently harvested. Four replicates per array. The supplementary file 'GSE19943_fold_pvalue.txt' contains fold-changes and p-values.
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