Project description:Purpose of arrays were to determine what the effect of deletion of Mbtps1 gene was on gene expression of osteocytes in bone in vivo. DMP1 cre driver was used to delete the Mbtps1 gene in osteocytes and osteoblasts in bone. We then isolated osteocyte enriched bone particles from 40 week old male mice to determine the effect of this deletion on gene expression. We have previously shown that Mbtps1 is needed for transcription of Phex, DMP1, and MEPE genes in osteoblasts in culture. Arrays showed these genes were reduced as expected in osteocytes in vivo. Controls represent osteocyte enriched bone from 40 week old littermates. Also, as expected, Mbtps1 expression was reduced in these knockout mice
Project description:Interestingly, the DMP1 cre Mbtps1 knockout mice do not demonstrate a noticeable bone phenotype despite gene expression changes. Only change was in bone stiffness. However, muscles from DMP1 cre Mbtps1 knockout mice did show a phenotype: changes in contractile force (increased); changes in myosin heavy chain expression, and an increase in myocyte regeneration evidenced by centralized nuclei in type I myosin heavy chain expressing cells. As a result, we wanted to know if these physiological changes were accompanied by changes in gene expression. We found that a number of genes were increased---including those associated with improved muscle performance and with activation of satellite cells, e.g., muscle stem cells. These changes in gene expression support our hypothesis which is that the bone (osteocytes) signal a change in muscle function via a cross-talk mechanism.
Project description:LLC1 cells were injected into the tibia of DMP1-Cre PhAM mice to study the intercellular mitochondrial transfer in the bone microenvironment. We used single-cell RNA sequencing (scRNA-seq) to analyze the cellular heterogeneity of osteocyte-derived mitochondria recipient cells.
Project description:Estrogens are well known steroid hormones necessary to maintain bone health. In addition, mechanical loading, which estrogen signaling may intersect with the Wnt/β-catenin pathway, is also essential for bone health. As osteocytes are known as the major mechanosensory cells embedded in mineralized bone matrix, osteocyte ERα deletion mice (ERαÎOcy/ÎOcy) were generated by mating ERα floxed mice with Dmp1-Cre mice to determine functions of ERα in osteocytes. Trabecular bone mineral density of female, but not male ERαÎOcy/ÎOcy mice was significantly decreased. Bone formation parameters in ERαÎOcy/ÎOcy were significantly decreased while osteoclast parameters were unchanged. This suggests that ERα in osteocytes exerts osteoprotective function by positively controlling bone formation. To identify potential targets of ERα, gene array analysis of Dmp1-GFP osteocytes FACS sorted from ERαÎOcy/ÎOcy and control mice was performed. Expression of Mdk and Sostdc1, both known inhibitors of Wnt, were significantly increased without alteration of the mature osteocyte marker Sost or β-catenin. Hindlimb unloading exacerbated the trabecular bone loss, but surprisingly cortical bone was resistant. These studies show that ERα in osteocytes has osteoprotective effects in trabecular bone through regulating expression of Wnt antagonists, but conversely plays a negative role in cortical bone loss due to unloading. Wild type and osteocyte-specific Estrogen Receptor alpha knock-out mice were generated. The number of both genotypes of mice was three. Calvarial osteocytes of both genotypes harboring Dmp1-GFP were extracted by sequential enzymatic digestion, followed by FACS Aria sorting and total RNAs were purified for Affymetix GeneChip microarray analysis without pooling.
Project description:In mouse bone marrow, mesenchymal stem cells (MSC) has the potential to form osteocytes, adipocytes and cartilage. In the process of osteogenesis, MSCs differenetiate into stromal cells, such as CAR cells. Osteoblast is responsible for the formation of osteocytes and osteoblasts may be differentiated from a subset of CAR cells. Dmp1-Cre targeted CAR cells are thought to enrich for a osteoblast progenitor population. We used microarrays to detail the gene expression profiles among Dmp1-Cre targeted and non-targeted CAR cells. Gene expression diffferences were compared to support the hypothesis that Dmp1-Cre targeted CAR cells may be enriched for osteoblast progenitors. Dmp1-Cre targeted and non-targeted CAR cells were FACS sorted from three mice. RNA were extracted from these sorted cells and processed for microarray using Affymetrix mogene 1.0 ST chip. Cells from one mouse represent one sample
Project description:Estrogens are well known steroid hormones necessary to maintain bone health. In addition, mechanical loading, which estrogen signaling may intersect with the Wnt/β-catenin pathway, is also essential for bone health. As osteocytes are known as the major mechanosensory cells embedded in mineralized bone matrix, osteocyte ERα deletion mice (ERαΔOcy/ΔOcy) were generated by mating ERα floxed mice with Dmp1-Cre mice to determine functions of ERα in osteocytes. Trabecular bone mineral density of female, but not male ERαΔOcy/ΔOcy mice was significantly decreased. Bone formation parameters in ERαΔOcy/ΔOcy were significantly decreased while osteoclast parameters were unchanged. This suggests that ERα in osteocytes exerts osteoprotective function by positively controlling bone formation. To identify potential targets of ERα, gene array analysis of Dmp1-GFP osteocytes FACS sorted from ERαΔOcy/ΔOcy and control mice was performed. Expression of Mdk and Sostdc1, both known inhibitors of Wnt, were significantly increased without alteration of the mature osteocyte marker Sost or β-catenin. Hindlimb unloading exacerbated the trabecular bone loss, but surprisingly cortical bone was resistant. These studies show that ERα in osteocytes has osteoprotective effects in trabecular bone through regulating expression of Wnt antagonists, but conversely plays a negative role in cortical bone loss due to unloading.
Project description:In mouse bone marrow, mesenchymal stem cells (MSC) has the potential to form osteocytes, adipocytes and cartilage. In the process of osteogenesis, MSCs differenetiate into stromal cells, such as CAR cells. Osteoblast is responsible for the formation of osteocytes and osteoblasts may be differentiated from a subset of CAR cells. Dmp1-Cre targeted CAR cells are thought to enrich for a osteoblast progenitor population. We used microarrays to detail the gene expression profiles among Dmp1-Cre targeted and non-targeted CAR cells. Gene expression diffferences were compared to support the hypothesis that Dmp1-Cre targeted CAR cells may be enriched for osteoblast progenitors.
Project description:We injected LLC1 cells into the tibia of DMP1-Cre Mfn2-/- mice, DMP1-Cre Rhot1-/- mice, and wild-type mice to study the changes in the cellular composition of the cancer microenvironment after knockout of Mfn2 or Rhot1 in osteocytes.
Project description:We determined the transcriptomic profile of bone-marrow derived macrophages (BMDMs) from LysMCre-mediated myeloid-specific Wdfy3 knockout mice and the Cre- littermate control mice.