Osteocytic FSH inhibition rescues bone mass and boosts fracture healing in ovariectomized mice
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE305679 | GEO | 2025/12/01
REPOSITORIES: GEO
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Project description:Osteocytic FSH inhibition rescues bone mass and boosts fracture healing in ovariectomized mice
| PRJNA1307458 | ENA
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.
2013-12-12 | E-GEOD-41997 | biostudies-arrayexpress
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
2015-12-29 | GSE69975 | GEO
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.
2024-01-01 | GSE228613 | GEO
Project description:Poor bone quality (BQ) is a major factor in skeletal fragility in the elderly. Molecular mechanisms establishing and maintaining BQ, independent of bone mass, are unknown but are thought to be primarily determined by osteocytes. We hypothesize that the age-related decline in BQ results from suppression of osteocyte perilacunar/canalicular remodeling (PLR), which maintains bone material properties. We examined bones from young and aged mice with an osteocyte-intrinsic repression of TGFbeta signaling (TbetaRIIocy-/-) that suppresses PLR. Control-aged bone displayed decreased TGFbeta signaling and PLR, but aging male TbetaRIIocy-/- bone did not worsen existing PLR suppression. This epistatic relationship impacted collagen material behavior at the nano and tissue scale in macromechanical tests. The effects of age on bone mass, density, and mineral material behavior were independent of osteocytic TGFbeta. We determine that the decline of BQ with age arises from lost osteocyte function and maintenance of collagen integrity in a TGFbeta-dependent fashion.
2023-03-14 | MSV000091488 | MassIVE
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.
2013-12-12 | GSE41997 | GEO
Project description:Glucocorticoids (GC) and parathyroid hormone (PTH) are widely used therapeutic endocrine hormones where their effects on bone and joint arise from actions on multiple skeletal cell types. In osteocytes, GC and PTH exert opposing effects on perilacunar canalicular remodeling (PLR). Suppressed PLR can impair bone quality and joint homeostasis, including in GC-induced osteonecrosis. However, combined effects of GC and PTH on PLR are unknown. Focusing on subchondral bone and joint homeostasis, we hypothesize that PTH, a PLR agonist, could rescue GC-suppressed PLR. The skeletal effects of GC and PTH, alone or combined, were examined in male and female mice by micro-computed tomography, mechanical testing, histology, and gene expression analysis. For each outcome, females were more responsive to GC and PTH than males. GC and PTH exerted regional differences, with GC increasing trabecular bone volume but reducing cortical bone thickness, stiffness, and ultimate force. Despite PTH’s anabolic effects on trabecular bone, it did not rescue GC’s catabolic effects on cortical bone. Likewise, cartilage integrity and subchondral bone apoptosis, alkaline phosphatase activity, and osteocyte lacunocanalicular networks showed no evidence that PTH could offset GC-dependent effects. Rather, GC and PTH each increased cortical bone gene expression implicated in bone resorption by osteoclasts and osteocytes, including Acp5, Mmp13, Atp6v0d2, Ctsk, differences maintained when GC and PTH were combined. Since PTH is insufficient to rescue GC’s effects on young female mouse bone, future studies are needed to determine if osteocyte PLR suppression, due to GC, aging, or other factors, can be offset by a PLR agonist.
2024-07-18 | GSE252085 | GEO
Project description:Comparison of osteocyte-enriched bone from DMP1 cre Mbtps1 knockout mice with littermate controls.
| PRJNA287321 | ENA
Project description:Osteocytes, positioned within boneâs interstitial space, are subject to fluid flow upon whole bone loading. Such fluid flow is widely theorized to be a mechanical signal transduced by osteocytes, initiating a poorly understood cascade of signaling events mediating bone metabolism. The objective of this study was to utilize high-throughput approaches to examine the time course of flow-induced changes in osteocyte gene transcript and protein levels. Microarray analysis demonstrated fluid flow regulation of genes consistent with known anabolic loading responses, including Ptgs2, NF-κB inhibitors, MAP3 kinases, and Wnt/β-catenin pathway signaling molecules. However, two of the most highly up-regulated gene productsâCxcl1 and Cxcl2, confirmed by qPCRâhave not previously been reported to be responsive to fluid flow. Gene ontology analysis suggested a highly significant inflammatory and immune response, with cellular functions including trafficking, cell-to-cell signaling, and tissue development. Proteomic analysis of the same samples demonstrated greatest up-regulation of the ATP-producing enzyme NDK, calcium-binding Calcyclin, and G protein-coupled receptor kinase 6. An integrative pathway analysis merging fold changes in transcript and protein levels predicted signaling nodes not directly detected at the sampled time points, including STAT3 and c-Myc. These results extend our knowledge of the osteocytic response to fluid flow, most notably up-regulation of Cxcl1 and Cxcl2 as a possible paracrine agent for osteoblastic and osteoclastic recruitment. Osteocyte-like MLO-Y4 cells were subjected to 2 hours of 10 dyn/cm2 oscillating fluid flow in parallel-plate fluid flow chambers and harvested for analysis at 0, 2, 8, and 24 hours post-flow incubation. Parallel control samples from sham treated cells were also collected at each time point.
2013-07-01 | E-GEOD-42874 | biostudies-arrayexpress
Project description:Genome-wide association studies (GWAS) have identified polycystic ovary syndrome (PCOS)-associated loci, including DENND1A encoding a clathrin-binding protein involved in vesicle transport as a guanine nucleotide exchange factor. The effect of DENND1A on reproduction and whether it participates in follicle development disorder and androgen synthesis in PCOS remain unknown. Here, we demonstrated that DENND1A expression increased in ovarian granulosa cells (GCs) of PCOS patients and was positively correlated with serum testosterone concentration. We constructed a systemic transgenic Dennd1a mouse (TG mouse) model, which showed subfertility, irregular estrous cycles, and increased production of testosterone after PMSG stimulation. Moreover, TG mice showed hyporesponsiveness to PMSG with smaller ovary size and less well-developed follicles. Intracellular follicle-stimulating hormone receptor (FSHR) transport was disturbed by overexpression of Dennd1a, which promoted FSHR internalization and inhibited its recycling. Our findings revealed the reproductive function of DENND1A and the underlying mechanisms, which provided new insights into the PCOS pathogenesis and contributing to drug design for PCOS treatment.
2023-07-05 | GSE236248 | GEO