Project description:High-throughput microRNA sequencing was used to identify microRNAs (miRs) that regulate osteoblast differentiation. We establish that miR-101a, which targets the epigenetic enzyme Ezh2, is up-regulated in differentiated MC3T3 cells and robustly expressed in mouse calvaria. Our previous studies showed that loss of Ezh2 function enhances osteogenesis and bone formation. Thus, we tested the attractive mechanistic model that increased miR-101s expression may suppress Ezh2 to stimulate the osteogenic process. Transient miR-101a over-expression suppresses Ezh2 levels and reduces tri-methylation on lysine 27 of histone 3 (H3K27me3), a heterochromatic mark catalyzed by Ezh2. Importantly, over-expression of miR-101a stimulates osteogenic differentiation of MC3T3 cells as quantified by alizarin red staining. Therefore, we examined skeletal phenotypes of mice transgenic for miR-101a under the control of Col1a1promoer and doxycycline administration. Experimental controls and mir-101 over-expressing mice were exposed to doxycycline during pregnancy and postnatal stages (phenotyping at 8 weeks) to maximize penetrance of skeletal phenotypes. Our analyses revealed that miR-101a over-expressing male mice are bigger as measured by total body weight and exhibit an increase in long bone length. These mice exhibit significant increases in trabecular bone volume fraction, trabecular number, trabecular thickness, as well as a reduction in trabecular spacing based on microCT analysis. Histomorphometric examination established a significant reduction in osteoid volume to bone volume and osteoid surface to bone surface. These findings suggest that the enhancement in trabecular bone may be due to accelerated bone mineralization in miR-101a over-expressing male mice. Remarkably, while female mice exhibit a significant increase in bone length, no significant changes were noted by microCT (trabecular bone parameters) and histomorphometry (osteoid parameters). We conclude that miR-101a upregulation during osteoblast maturation enhances trabecular bone parameters in male mice. Thus, miR-101 and Ezh2 may form part of an intricate epigenetic feed-forward mechanisms to regulate bone formation.
Project description:Trabecular meshwork cells in eyes with glaucoma aquire mesenchymal phenotypes. The types of microRNAs in exosomes may differ between static and glaucomatous status and their effects on aqueous humor regulation are still uknown. We used microarrays to identify the differential microRNA expression related to interaction between trabecular meshwork cells and Schlemm's canal endothelial cells.
Project description:This SuperSeries is composed of the following subset Series:; GSE12264: Gene Expression Profile of Osteogenic Cells Derived from Human Bone Marrow and Trabecular Bone I; GSE12265: Gene Expression Profile of Osteogenic Cells Derived from Human Bone Marrow and Trabecular Bone II; GSE12266: Gene Expression Profile of Osteogenic Cells Derived from Human Bone Marrow and Trabecular Bone III Experiment Overall Design: Refer to individual Series
Project description:Type I diabetes (T1D) impairs bone accrual in patients, but the mechanism is unclear. Here in a murine monogenic model for T1D, we demonstrate that diabetes suppresses bone formation resulting in a rapid loss of both cortical and trabecular bone. Single-cell RNA sequencing uncovers metabolic dysregulation in bone marrow osteogenic cells of the diabetic mice. In vivo stable isotope tracing reveals impaired glycolysis in diabetic bone that is highly responsive to insulin stimulation. Remarkably, deletion of the insulin receptor reduces cortical but not trabecular bone. Increasing glucose uptake by overexpressing Glut1 in osteoblasts exacerbates bone defects in T1D mice. Conversely, activation of glycolysis by Pfkfb3 overexpression preserves both trabecular and cortical bone mass in the face of diabetes. The study identifies defective glucose metabolism in osteoblasts as a pathogenic mechanism for osteopenia in T1D, and furthermore implicates boosting osteoblast glycolysis as a potential anabolic therapy.
Project description:Type I diabetes (T1D) impairs bone accrual in patients, but the mechanism is unclear. Here in a murine monogenic model for T1D, we demonstrate that diabetes suppresses bone formation resulting in a rapid loss of both cortical and trabecular bone. Single-cell RNA sequencing uncovers metabolic dysregulation in bone marrow osteogenic cells of the diabetic mice. In vivo stable isotope tracing reveals impaired glycolysis in diabetic bone that is highly responsive to insulin stimulation. Remarkably, deletion of the insulin receptor reduces cortical but not trabecular bone. Increasing glucose uptake by overexpressing Glut1 in osteoblasts exacerbates bone defects in T1D mice. Conversely, activation of glycolysis by Pfkfb3 overexpression preserves both trabecular and cortical bone mass in the face of diabetes. The study identifies defective glucose metabolism in osteoblasts as a pathogenic mechanism for osteopenia in T1D, and furthermore implicates boosting osteoblast glycolysis as a potential anabolic therapy.
Project description:Myeloma bone disease is a devastating complication of multiple myeloma (MM) and is caused by dysregulation of bone remodeling processes in the bone marrow microenvironment. Previous studies showed that microRNA-138 (miR-138) is a negative regulator of osteogenic differentiation of mesenchymal stromal cells (MSCs) and that inhibiting its function enhances bone formation in vitro. In this study, we explored the role of miR-138 in myeloma bone disease and evaluated the potential of systemically delivered locked nucleic acid (LNA)-modified anti-miR-138 oligonucleotides in suppressing myeloma bone disease. We showed that expression of miR-138 was significantly increased in MSCs from MM patients (MM-MSCs) and myeloma cells compared to those from healthy subjects. Furthermore, inhibition of miR-138 resulted in enhanced osteogenic differentiation of MM-MSCs in vitro and increased number of endosteal osteoblastic lineage cells (OBCs) and bone formation rate in mouse models of myeloma bone disease. RNA sequencing of the OBCs identified TRPS1 and SULF2 as potential miR-138 targets that were de-repressed in anti-miR-138 treated mice. In summary, these data indicate that inhibition of miR-138 enhances bone formation in MM and that pharmacological inhibition of miR-138 could represent a new therapeutic strategy for treatment of myeloma bone disease.
Project description:We used single cell RNA sequencing (scRNAseq) to show that ventricular endocardial cells generate trabecular vessels through an angioEMT mechanism.