Project description:We analyzed SOX9 binding and the global effect of SOX9 overexpression on chromatin accessibility and enrichment of histone modifications (H3K4me1, H3K27ac, H3K27me3, H3S28P) by CUT&RUN, CUT&Tag, and ATAC-seq of HUVECs transduced with SOX9 expression plasmid or an empty vector control.
Project description:We compared Sox9-association at chondrocyte targets to a broad catalogue of regulatory indicators of chromatin organization and transcriptional activity to determine Sox9’s direct regulatory actions in normal developing chondrocytes. Sox9-associated regions resolve into two distinct regulatory categories. Class I regions closely associate with transcriptional start sites (TSSs). Their targets reflect general regulators of basal cell activities that Sox9 engages indirectly though a likely association with the basal transcriptional complex. In contrast, Class II regions outside of the local TSS domains highlight evolutionarily conserved, active enhancers directing expression of chondrocyte specific target genes, though DNA binding of Sox9-dimers at target sites with sub-optimal binding affinity. The level of associated chondrocyte gene expression correlates with the number of enhancer modules around the target gene and grouping into super-enhancer clusters. Comparison of Sox9 programs between neural crest and mesoderm-derived chondrocytes points to similar modes of chondrocyte specification in distinct chondrocyte lineages. These data provide the first insight into mammalian Sox family actions at the genome scale in the vivo setting. The resulting enhancer sets provide a key resource for further dissection of the regulatory programs of mammalian chondrogenesis. Incorportation of ChIP-seq data of Sox9 and histone modification marks for chromatin status together with micorarray gene expression profiling in neonatal mice chondrocytes to uncover Sox9 regulatory system. Overexpression of Sox9 with a control of EGFP in human fibroblasts to identify the direct targets of Sox9 regulatory system
Project description:Introduction: In addition to the well-known cartilage extracellular matrix-related expression of Sox9, we demonstrated that chondrogenic differentiation of progenitor cells is driven by a sharply defined bi-phasic expression of Sox9: an immediate early and a late (extracellular matrix associated) phase expression. In this study we aimed to determine what biological processes are driven by Sox9 during this early phase of chondrogenic differentiation. Materials: Sox9 expression in ATDC5 cells was knocked-down by siRNA transfection at the day before chondrogenic differentiation or at day 6 of differentiation. Samples were harvested at 2 hours, and 7 days of differentiation. The transcriptomes (RNA-seq approach) and proteomes (Label-free proteomics approach) were compared using pathway and network analyses. Total protein translational capacity was evaluated with the SuNSET assay, active ribosomes with polysome profiling and ribosome modus with bicistronic reporter assays. Results: Early Sox9 knockdown severely inhibited chondrogenic differentiation weeks later. Sox9 expression during the immediate early phase of ATDC5 chondrogenic differentiation regulated the expression of ribosome biogenesis factors and ribosomal protein subunits. This was accompanied by decreased translational capacity following Sox9 knockdown, and this correlated to lower amounts of active mono- and polysomes. Moreover, cap- versus IRES-mediated translation was altered by Sox9 knockdown. Sox9 overexpression was able to induce reciprocal effects to the Sox9 knockdown. Conclusion: Here we identified an essential new function for Sox9 during early chondrogenic differentiation. A role for Sox9 in regulation of ribosome amount, activity and/or composition may be crucial in preparation for the demanding proliferative phase and subsequent cartilage extracellular matrix-production of chondroprogenitors in the growth plate in vivo.
Project description:Vascular calcification and increased extracellular matrix (ECM) stiffness are hallmarks of vascular ageing. Sox9 (SRY-Box Transcription Factor 9) is a master regulator of chondrogenesis, also expressed in the vasculature, that has been implicated in vascular smooth muscle cell (VSMC) osteo-chondrogenic conversion. Here, we investigated the relationship between vascular ageing, calcification and Sox9-driven ECM regulation in VSMCs. Immunohistochemistry in human aortic samples showed that Sox9 was not spatially associated with vascular calcification but correlated with the senescence marker p16. Analysis of Sox9 expression in vitro showed it was mechanosensitive with increased expression and nuclear translocation in senescent cells and on stiff matrices. Manipulation of Sox9 via overexpression and depletion, combined with atomic force microscopy (AFM) and proteomics, revealed that Sox9 regulates ECM stiffness and organisation by orchestrating changes in collagen expression and reducing VSMC contractility, leading to the formation of an ECM that mirrored that of senescent cells. These ECM changes promoted phenotypic modulation of VSMCs whereby senescent cells plated onto ECM synthesized from cells depleted of Sox9 returned to a proliferative state, while proliferating cells on a matrix produced by Sox9 expressing cells showed reduced proliferation and increased DNA damage, reiterating features of senescent cells. Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 3 (LH3) was identified as a Sox9 target, and key regulator of ECM stiffness. LH3 is packaged into extracellular vesicles (EVs) and Sox9 promoted EV secretion, leading to increased LH3 deposition within the ECM. These findings identify cellular senescence and Sox9 as a key regulators of ECM stiffness during VSMC ageing and highlight a crucial role for ECM structure and composition in regulating VSMC phenotype. We identify a positive feedback cycle whereby cellular senescence and increased ECM stiffening promote Sox9 expression which drives further ECM modifications that act to accelerate vascular stiffening and cellular senescence.
Project description:The goal of this study was to profile active H3K27ac marks between autochthonous mouse models of high-grade glioma (HGG) and ependymoma (EPN). Furthermore, with the objective of how transcription factor Sox9 affect H3K27ac states in these two models, we also profiled H3K27ac status between HGG and EPN after Sox9 overexpression (Sox9-GOF) or deletion (Sox9-LOF) in each of these models. In addition, we extended our studies to evaluate both H3K27ac and Sox9 states in human HGG and mouse EPN derived tumor cells.
Project description:SOX9 is generally not expressed in melanomas with a high proliferative capacity but is expressed in melanomas with a high invasive capacity. Here we overexpress full length SOX9 in M010817, a melanoma cell culture with high proliferative capacity but low invasive capacity. 3x Control vector. 3x SOX9 overexpression
Project description:We analyzed the global effect of SOX9 overexpression by sequencing the transcriptomes of HUVECs transduced with SOX9 expression plasmid or an empty vector control.
Project description:Sorafenib is a multi-kinase blocker and one of the few suggested drug treatments for aggressive hepatocellular carcinoma (HCC) patients. However, drug resistance to sorafenib may often occur over time and cause further tumor aggression. Recently, cancer stem cells were found in HCC and were speculated to be involved in tumor progression. SOX9 is highly expressed in HCC cancer stem cells and promotes cell proliferation and self-renewal. Meanwhile, HCC patients with higher SOX9 expression show poorer prognosis [1]. Whether SOX9 is involved in sorafenib resistance in HCC is still unclear. Here, we found that sorafenib treatment increased SOX9 expression in HCC cell lines. Overexpression of exogenous SOX9 in HCC increased sorafenib resistance both in vitro and in vivo, whereas down-regulation led to inhibition of sorafenib resistance. Knock-down of SOX9 by RNA interference caused down-regulation of downstream genes, including ATP binding cassette subfamily G member 2 (ABCG2). The drug resistance to sorafenib caused by SOX9 overexpression could be ameliorated by overexpression of SOX9 in combination withby ABCG2 inhibition in HCC cell lines. In the cohort of patients resistant to sorafenib, we found that patients with lower SOX9 expression had more prolonged overall survival (OS) and progression-free survival (PFS). Cox analysis shows that SOX9 expression exerts as an independent risk factor for HCC, and logistic regression analysis reveals that SOX9 expression, tumor capsule deficiency, tumor diameters, and microvascular invasion are risk factors for poor prognosis of HCC patients. These findings demonstrate that SOX9 enhances sorafenib resistance and may regulate this process by modulating ABCG2 expression.