Project description:UMR106-01 osteoblastic cells are a model for studying bone mineralization. We have shown that mineralization is temporally synchronized within cultures grown under defined conditions . Cells are plated at time zero and differentiate into osteoblastic phenotype by 64 h later. If an exogenous phosphate source is added to the cultures, the cells form and deposit hydroxyapatite mineral within distinct extracellular supramolecular lipid protein complexes termed biomineralization foci (BMF) starting 12 h later. Mineralization is largely complete by 24 h later (88 h after plating). We have also shown that AEBSF, covalent serine protease inhibitor, blocks mineralization within BMF and inhibits the fragmentation of several proteins related to biomineralization. The present experiment was designed to test whether AEBSF treatment for 12 h has an effect on transcription by UMR106-01 osteoblastic cells. AEBSF is known to inactivate several serine proteases including SKI-1 (site 1, subtilisin kexin protease-1).SKI-1 functions intracellularly to activate transmembrane bound transcription factor precursors releasing the transcriptionally active N-terminal portions to imported into the nucleus. Thus, if AEBSF blocks transcription of mineralization related genes, it would support a role for SKI-1 in gene regulation in mineralizing UMR106-01 osteoblastic cells. Comparison of triplicate cultures treated with mineralizing conditions with triplicate cultures treated with AEBSF protease inhibitor for 12 h.
Project description:UMR106-01 osteoblastic cells are a model for studying bone mineralization. We have shown that mineralization is temporally synchronized within cultures grown under defined conditions . Cells are plated at time zero and differentiate into osteoblastic phenotype by 64 h later. If an exogenous phosphate source is added to the cultures, the cells form and deposit hydroxyapatite mineral within distinct extracellular supramolecular lipid protein complexes termed biomineralization foci (BMF) starting 12 h later. Mineralization is largely complete by 24 h later (88 h after plating). We have also shown that AEBSF, covalent serine protease inhibitor, blocks mineralization within BMF and inhibits the fragmentation of several proteins related to biomineralization. The present experiment was designed to test whether AEBSF treatment for 12 h has an effect on transcription by UMR106-01 osteoblastic cells. AEBSF is known to inactivate several serine proteases including SKI-1 (site 1, subtilisin kexin protease-1).SKI-1 functions intracellularly to activate transmembrane bound transcription factor precursors releasing the transcriptionally active N-terminal portions to imported into the nucleus. Thus, if AEBSF blocks transcription of mineralization related genes, it would support a role for SKI-1 in gene regulation in mineralizing UMR106-01 osteoblastic cells.
Project description:Beyond forming bone, osteoblasts play pivotal roles in various biological processes, including hematopoiesis and bone metastasis. Extracellular vesicles (EVs) have recently been implicated in intercellular communication via transfer of proteins and nucleic acids between cells. Here, we focused on the proteomic characterization of non-mineralizing (NMOBs) and mineralizing (MOBs) human osteoblast (SV-HFOs) EVs and investigated their effect on human prostate cancer (PC3) cells by microscopic, proteomic and gene expression analyses. Proteomic analysis showed that 97% of the proteins were shared among NMOB and MOB EVs, and 30% were novel osteoblast-specific EV proteins. Label-free quantification demonstrated mineralization stage-dependent five-fold enrichment of 59 and 451 EV proteins in NMOBs and MOBs, respectively. Interestingly, bioinformatic analyses of the osteoblast EV proteomes and EV-regulated prostate cancer gene expression profiles showed that they converged on pathways involved in cell survival and growth. This was verified by in vitro proliferation assays where osteoblast EV uptake led to two-fold increase in PC3 cell growth compared to cell-free culture medium-derived vesicle controls. Our findings elucidate the mineralization stage-specific protein content of osteoblast-secreted EVs, show a novel way by which osteoblasts communicate with prostate cancer, and open up innovative avenues for therapeutic intervention. PC3 cells were treated with extracellular vesicles from non-mineralizing and mineralizing SV-HFOs for three different incubation times (4hrs, 24hrs, 48hr)
Project description:Inflammation is a key component of pathological angiogenesis. Here we induce cornea neovascularisation using sutures placed into the cornea, and sutures are removed to induce a regression phase. We used whole transcriptome microarray to monitor gene expression profies of several genes