Project description:Different osteoprogenitors (SSC, BCSP, Thy+) were sorted after 2 days of JUN induction, followed by RNA extraction and microarray analysis
Project description:Prenatal dexamethasone exposure (PDE) has long-term consequences in bone development. we investigated how PDE exerts persistent effect on bone metabolism in mouse offspring. Our results showed that PDE offspring exhibited reduced bone mass, fewer osteoblasts and diminished osteoprogenitors proliferation.And PDE increased MKP-1 expression, while decreasing H3 lysine 9 dimethylation (H3K9me2) at Mkp-1 gene locus. Mechanistically, dexamethasone suppressed osteoprogenitors proliferation by upregulating MKP-1 expression, notably through the inhibition of H3K9me2 modifications, which promoted demethylation and transcriptional activation of the Mkp-1 gene. Importantly, restoring histone methylation balance with PFI-90 treatment blocked the inhibitory effects of PDE on MAPK signaling in osteoprogenitors, and mitigated the detrimental impact of PDE on osteoprogenitor proliferation and bone development in the offspring. Therefore,we performed ChIP-seq for H3K9me2 to identify its role in related epigenetic changes.
Project description:To investigate cellular population heterogeneity, and gene expression in osteoprogenitors and other cell types (endothelial, osteogenic, immune) we isolate the calvarial periosteum and sagittal sutures as stem cell compartments that contribute to osteogenesis. We compare cell populations and gene expression between different ages of mouse, and also between different diets (ad libitum vs intermittent fasting)
Project description:To further dissect whether and how activated JUN reconfigures the chromatin landscape, we performed Chromatin Immunoprecipitation (ChIP)-seq analyses for H3K4me1 and H3K27ac. Based on the significant increase of H3K27ac levels at H3K4me1+ sites, we identified 3,017 JUN-activated enhancers in JUN WT cells. In contrast, JUN AA fails to significantly induce H3K27ac accumulation at these regions. Their enrichment levels at JUN-activated enhancers were significantly decreased after JNKi treatment. Besides, these enhancers are directly driven by JUN, especially phosphorylated JUN.
Project description:Clinical evidence has established that concomitant traumatic brain injury accelerates bone healing, but the underlying mechanism is unclear. This study showed that after TBI, injured neurons, mainly those in the hippocampus, released osteogenic microRNA (miRNA)-enriched exosomes, which targeted osteoprogenitors in bone to stimulate bone formation. Importantly, increased fibronectin expression on exosomal surface contributed to targeting of osteoprogenitors in bone by TBI exosomes, thereby implying that modification of the exosome surface fibronectin could be used in bone-targeted drug delivery. Together, our findings have established a novel role of central regulation in bone formation and a clear link between injured neurons and osteogenitors, both in animals and clinical settings.
Project description:We found that JUN expression is increased in many human fibrotic diseases and that systemic induction of Jun in mice resulted in development of fibrosis of multiple organs. To identify the changes in chromatin accessibility associated with JUN, we worked with primary human fibrotic lung fibroblasts that have normal or Knock-out levels of JUN expression and performed ATAC-seq analysis in both of them. Meanwhile we also modified primary human normal lung fibroblasts with or without JUN over-expression induction, then processed ATAC-seq and ChIP-seq analysis.