scholarly journals Kindlin-2 regulates skeletal homeostasis by modulating PTH1R in mice

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Xuekun Fu ◽  
Bo Zhou ◽  
Qinnan Yan ◽  
Chu Tao ◽  
Lei Qin ◽  
...  
Keyword(s):  
Bone Mass ◽  
Volume Fraction ◽  
Bone Marrow Cells ◽  
Bone Matrix ◽  
Osteoblastic Cells ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Ovariectomized Mice

AbstractIn vertebrates, the type 1 parathyroid hormone receptor (PTH1R) is a critical regulator of skeletal development and homeostasis; however, how it is modulated is incompletely understood. Here we report that deleting Kindlin-2 in osteoblastic cells using the mouse 10-kb Dmp1-Cre largely neutralizes the intermittent PTH-stimulated increasing of bone volume fraction and bone mineral density by impairing both osteoblast and osteoclast formation in murine adult bone. Single-cell profiling reveals that Kindlin-2 loss increases the proportion of osteoblasts, but not mesenchymal stem cells, chondrocytes and fibroblasts, in non-hematopoietic bone marrow cells, with concomitant depletion of osteoblasts on the bone surfaces, especially those stimulated by PTH. Furthermore, haploinsufficiency of Kindlin-2 and Pth1r genes, but not that of either gene, in mice significantly decreases basal and, to a larger extent, PTH-stimulated bone mass, supporting the notion that both factors function in the same genetic pathway. Mechanistically, Kindlin-2 interacts with the C-terminal cytoplasmic domain of PTH1R via aa 474–475 and Gsα. Kindlin-2 loss suppresses PTH induction of cAMP production and CREB phosphorylation in cultured osteoblasts and in bone. Interestingly, PTH promotes Kindlin-2 expression in vitro and in vivo, thus creating a positive feedback regulatory loop. Finally, estrogen deficiency induced by ovariectomy drastically decreases expression of Kindlin-2 protein in osteocytes embedded in the bone matrix and Kindlin-2 loss essentially abolishes the PTH anabolic activity in bone in ovariectomized mice. Thus, we demonstrate that Kindlin-2 functions as an intrinsic component of the PTH1R signaling pathway in osteoblastic cells to regulate bone mass accrual and homeostasis.

scholarly journals Early-Onset Type 2 Diabetes Impairs Skeletal Acquisition in the Male TALLYHO/JngJ Mouse

Endocrinology ◽  
2014 ◽  
Vol 155 (10) ◽  
pp. 3806-3816 ◽  
Author(s):  
M. J. Devlin ◽  
M. Van Vliet ◽  
K. Motyl ◽  
L. Karim ◽  
D. J. Brooks ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Bone Marrow ◽  
Bone Mass ◽  
Early Onset ◽  
Volume Fraction ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Skeletal Acquisition

Abstract Type 2 diabetes (T2D) incidence in adolescents is rising and may interfere with peak bone mass acquisition. We tested the effects of early-onset T2D on bone mass, microarchitecture, and strength in the TALLYHO/JngJ mouse, which develops T2D by 8 weeks of age. We assessed metabolism and skeletal acquisition in male TALLYHO/JngJ and SWR/J controls (n = 8–10/group) from 4 weeks to 8 and 17 weeks of age. Tallyho mice were obese; had an approximately 2-fold higher leptin and percentage body fat; and had lower bone mineral density vs SWR at all time points (P < .03 for all). Tallyho had severe deficits in distal femur trabecular bone volume fraction (−54%), trabecular number (−27%), and connectivity density (−82%) (P < .01 for all). Bone formation was higher in Tallyho mice at 8 weeks but lower by 17 weeks of age vs SWR despite similar numbers of osteoblasts. Bone marrow adiposity was 7- to 50-fold higher in Tallyho vs SWR. In vitro, primary bone marrow stromal cell differentiation into osteoblast and adipocyte lineages was similar in SWR and Tallyho, suggesting skeletal deficits were not due to intrinsic defects in Tallyho bone-forming cells. These data suggest the Tallyho mouse might be a useful model to study the skeletal effects of adolescent T2D.

Healing Cranial Defects with AdRunx2-transduced Marrow Stromal Cells

2007 ◽  
Vol 86 (12) ◽  
pp. 1207-1211 ◽  
Author(s):  
Z. Zhao ◽  
Z. Wang ◽  
C. Ge ◽  
P. Krebsbach ◽  
R.T. Franceschi
Keyword(s):  
Stromal Cells ◽  
Volume Fraction ◽  
Marrow Stromal Cells ◽  
Osteogenic Potential ◽  
Specific Gene ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Calvarial Defects

Marrow stromal cells (MSCs) include stem cells capable of forming all mesenchymal tissues, including bone. However, before MSCs can be successfully used in regeneration procedures, methods must be developed to stimulate their differentiation selectively to osteoblasts. Runx2, a bone-specific transcription factor, is known to stimulate osteoblast differentiation. In the present study, we tested the hypothesis that Runx2 gene therapy can be used to heal a critical-sized defect in mouse calvaria. Runx2-engineered MSCs displayed enhanced osteogenic potential and osteoblast-specific gene expression in vitro and in vivo. Runx2-expressing cells also dramatically enhanced the healing of critical-sized calvarial defects and increased both bone volume fraction and bone mineral density. These studies provide a novel route for enhancing osteogenesis that may have future therapeutic applications for craniofacial bone regeneration.

scholarly journals Semaphorin 3A Shifts Adipose Mesenchymal Stem Cells towards Osteogenic Phenotype and Promotes Bone Regeneration In Vivo

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Xiangwei Liu ◽  
Naiwen Tan ◽  
Yuchao Zhou ◽  
Xueying Zhou ◽  
Hui Chen ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Bone Regeneration ◽  
Volume Fraction ◽  
Calcium Deposition ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Adipose Mesenchymal Stem Cells

Adipose mesenchymal stem cells (ASCs) are considered as the promising seed cells for bone regeneration. However, the lower osteogenic differentiation capacity limits its therapeutic efficacy. Identification of the key molecules governing the differences between ASCs and BMSCs would shed light on manipulation of ASCs towards osteogenic phenotype. In this study, we screened semaphorin family members in ASCs and BMSCs and identified Sema3A as an osteogenic semaphorin that was significantly and predominantly expressed in BMSCs. The analyses in vitro showed that the overexpression of Sema3A in ASCs significantly enhanced the expression of bone-related genes and extracellular matrix calcium deposition, while decreasing the expression of adipose-related genes and thus lipid droplet formation, resembling a BMSCs phenotype. Furthermore, Sema3A modified ASCs were then engrafted into poly(lactic-co-glycolic acid) (PLGA) scaffolds to repair the critical-sized calvarial defects in rat model. As expected, Sema3A modified ASCs encapsulation significantly promoted new bone formation with higher bone volume fraction and bone mineral density. Additionally, Sema3A was found to simultaneously increase multiple Wnt related genes and thus activating Wnt pathway. Taken together, our study here identifies Sema3A as a critical gene for osteogenic phenotype and reveals that Sema3A-modified ASCs would serve as a promising candidate for bettering bone defect repair.

scholarly journals Estrogen Stimulation of Pleiotrophin Enhances Osteoblast Differentiation and Maintains Bone Mass in IGFBP-2 Null Mice

Endocrinology ◽  
2020 ◽  
Vol 161 (4) ◽  
Author(s):  
Gang Xi ◽  
Victoria E Demambro ◽  
Susan D’Costa ◽  
Shalier K Xia ◽  
Zach C Cox ◽  
...  
Keyword(s):  
Bone Mass ◽  
Osteoblast Differentiation ◽  
Volume Fraction ◽  
Tyrosine Phosphatase ◽  
Areal Bone Mineral Density ◽  
Wild Type ◽  
Mineral Density ◽  
Bone Volume Fraction ◽  
Skeletal Phenotype

Abstract Insulin-like growth factor binding protein-2 (IGFBP-2) stimulates osteoblast differentiation but only male Igfbp2 null mice have a skeletal phenotype. The trophic actions of IGFBP-2 in bone are mediated through its binding to receptor tyrosine phosphatase beta (RPTPβ). Another important ligand for RPTPβ is pleiotrophin (PTN), which also stimulates osteoblast differentiation. We determined the change in PTN and RPTPβ in Igfbp2–/– mice. Analysis of whole bone mRNA in wild-type and knockout mice revealed increased expression of Ptn. Rptpβ increased in gene-deleted animals with females having greater expression than males. Knockdown of PTN expression in osteoblasts in vitro inhibited differentiation, and addition of PTN to the incubation medium rescued the response. Estradiol stimulated PTN secretion and PTN knockdown blocked estradiol-stimulated differentiation. PTN addition to IGFBP-2 silenced osteoblast stimulated differentiation, and an anti-fibronectin-3 antibody, which inhibits PTN binding to RPTPβ, inhibited this response. Estrogen stimulated PTN secretion and downstream signaling in the IGFBP-2 silenced osteoblasts and these effects were inhibited with anti-fibronectin-3. Administration of estrogen to wild-type and Igfbp2–/– male mice stimulated an increase in both areal bone mineral density and trabecular bone volume fraction but the increase was significantly greater in the Igfbp2–/– animals. Estrogen also stimulated RPTPβ expression in the null mice. We conclude that loss of IGFBP-2 expression is accompanied by upregulation of PTN and RPTPβ expression in osteoblasts, that the degree of increase is greater in females due to estrogen secretion, and that this compensatory change may account for some component of the maintenance of normal bone mass in female mice.

IGF-binding protein-5 stimulates osteoblast activity and bone accretion in ovariectomized mice

2001 ◽  
Vol 281 (2) ◽  
pp. E283-E288 ◽  
Author(s):  
Dennis L. Andress
Keyword(s):  
Bone Formation ◽  
Binding Protein ◽  
Formation Rate ◽  
Bone Matrix ◽  
Secretory Protein ◽  
Mineral Density ◽  
Bone Formation Rate ◽  
Ovariectomized Mice ◽  
Osteoblast Activity

Insulin-like growth factor binding protein-5 (IGFBP-5) is an osteoblast secretory protein that becomes incorporated into the mineralized bone matrix. In osteoblast cultures, IGFBP-5 stimulates cell proliferation by an IGF-independent mechanism. To evaluate whether IGFBP-5 can stimulate osteoblast activity and enhance bone accretion in a mouse model of osteoblast insufficiency, daily subcutaneous injections of either intact [IGFBP-5 (intact)] or carboxy-truncated IGFBP-5 [IGFBP-5-(1–169)] were given to ovariectomized (OVX) mice for 8 wk. Femur and spine bone mineral density (BMD), measured every 2 wk, showed early and sustained increases in response to IGFBP-5. Bone histomorphometry of cancellous bone showed significant elevations in the bone formation rate in both the femur metaphysis [IGFBP-5- (1)] only) and spine compared with OVX controls. IGFBP-5 also stimulated osteoblast number in the femur IGFBP-5-(1–169) only) and spine. These data indicate that IGFBP-5 effectively enhances bone formation and bone accretion in OVX mice by stimulating osteoblast activity. The finding that IGFBP-5-(1–169) is bioactive in vivo indicates that the carboxy-terminal portion is not required for this bone anabolic effect.

scholarly journals Risedronate Effects on the In Vivo Bioactive Glass Behavior: Nuclear Magnetic Resonance and Histopathological Studies

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Siwar Mosbahi ◽  
Hassane Oudadesse ◽  
Claire Roiland ◽  
Bertrand Lefeuvre ◽  
Lotfi Slimani ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Bioactive Glass ◽  
Volume Fraction ◽  
Chemical Reactivity ◽  
Femoral Condyle ◽  
Mineral Density ◽  
Nuclear Magnetic

The present study aimed to enhance the anti-osteoporotic performance of bioactive glass (46S6) through its association with bisphosphonate such as risedronate with amounts of 8, 12, and 20%. Obtained composites have been called 46S6-8RIS, 46S6-12RIS, and 46S6-20RIS, respectively. In vitro and in vivo explorations have been carried out. Bioactive glass and risedronate association has been performed by adsorption process. Structure analyses have been carried out to evaluate and to understand their chemical interactions. Solid Nuclear Magnetic Resonance (NMR) has been employed to study the structural properties of obtained biocomposite. The spectra deconvolution showed the appearance of a species (Q4) in the biocomposites 46S6-8RIS, 46S6-12RIS, and 46S6-20RIS indicating their successful chemical association. In vitro experiments showed the enhancement of the chemical reactivity of the composites 46S6-xRIS compared to the pure bioactive glass. In fact, the silicon liberation after 30 days of immersion was 50 ppm for pure bioactive glass 46S6, and 41, 64, and 62 from 46S6-8RIS, 46S6-12RIS, and 46S6-20RIS, respectively. Based on the in vitro results, 46S6-8RIS was implanted in the femoral condyle of an ovariectomized rat and compared with implanted pure glass in the goal to highlight its anti-osteoporotic performance. After 60 days, implanted group with 46S6-8RIS showed the increase in bone mineral density (BMD with 10%) and bone volume fraction (BV/TV with 80%) and the decrease in trabecular separation (Tb/Sp with 74%) when compared to that of 46S6 group. These results are confirmed by the histopathological analyses, which showed the bone trabeculae reconnection after the 46S6-8RIS implantation. Chemical analyses showed the reduction in silicon (Si) and sodium (Na) ion concentrations, and the rise in calcium (Ca) and phosphorus (P) ion levels, which was explained by the dissolution of biocomposite matrix and the deposition of hydroxyapatite layer. Histomorphometric results highlighted the risedronate effect on the antiosteoporotic phenomenon. Obtained results showed good behavior with only 8% of introduced risedronate in the glass matrix.

Identification and Functional Characterization of Metabolites for Bone Mass in Peri-/Post-menopausal Chinese Women

2021 ◽  
Author(s):  
Rui Gong ◽  
Hong-Mei Xiao ◽  
Yin-Hua Zhang ◽  
Qi Zhao ◽  
Kuan-Jui Su ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Bone Loss ◽  
Osteoclast Differentiation ◽  
Dodecanoic Acid ◽  
Mineral Density ◽  
Ovariectomized Mice ◽  
Post Menopausal ◽  
Functional Mechanisms

Abstract Context Although metabolic profiles appear to play an important role in menopausal bone loss, the functional mechanisms by which metabolites influence bone mineral density (BMD) during menopause are largely unknown. Objective We aimed to systematically identify metabolites associated with BMD variation and their potential functional mechanisms in peri-/post-menopausal women. Design and Methods We performed serum metabolomic profiling and whole-genome sequencing for 517 perimenopausal (16%) and early postmenopausal (84%) women aged 41 to 64 years in this cross-sectional study. Partial least squares (PLS) regression and general linear regression analysis were applied to identify BMD-associated metabolites, and weighted gene co-expression network analysis was performed to construct co-functional metabolite modules. Furthermore, we performed Mendelian randomization analysis to identify causal relationships between BMD-associated metabolites and BMD variation. Finally, we explored the effects of a novel prominent BMD-associated metabolite on bone metabolism through both in vivo/in vitro experiments. Results Twenty metabolites and a co-functional metabolite module (consisting of fatty acids) were significantly associated with BMD variation. We found dodecanoic acid (DA), within the identified module, causally decreased total hip BMD. Subsequently, the in vivo experiments might support that dietary supplementation with DA could promote bone loss, as well as increase the osteoblast and osteoclast numbers in normal/ovariectomized mice. DA treatment differentially promoted osteoblast and osteoclast differentiation, especially for osteoclast differentiation at higher concentrations in vitro (e.g.,10, 100μM). Conclusions This study sheds light on metabolomic profiles associated with postmenopausal osteoporosis risk, highlighting the potential importance of fatty acids, as exemplified by DA, in regulating BMD.

scholarly journals Osteoporosis Recovery byAntrodia camphorataAlcohol Extracts through Bone Regeneration in SAMP8 Mice

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hen-Yu Liu ◽  
Chiung-Fang Huang ◽  
Chun-Hao Li ◽  
Ching-Yu Tsai ◽  
Wei-Hong Chen ◽  
...  
Keyword(s):  
Bone Loss ◽  
Bone Matrix ◽  
Mineral Density ◽  
Antrodia Camphorata ◽  
Osteoporosis Therapy ◽  
Alizarin Red ◽  
Alcohol Extract ◽  
Samp8 Mice

Antrodia camphoratahas previously demonstrated the efficacy in treating cancer and anti-inflammation. In this study, we are the first to evaluateAntrodia camphorataalcohol extract (ACAE) for osteoporosis recoveryin vitrowith preosteoblast cells (MC3T3-E1) andin vivowith an osteoporosis mouse model established in our previous studies, ovariectomized senescence accelerated mice (OVX-SAMP8). Our results demonstrated that ACAE treatment was slightly cytotoxic to preosteoblast at 25 μg/mL, by which the osteogenic gene expression (RUNX2, OPN, and OCN) was significantly upregulated with an increased ratio of OPG to RANKL, indicating maintenance of the bone matrix through inhibition of osteoclastic pathway. Additionally, evaluation by Alizarin Red S staining showed increased mineralization in ACAE-treated preosteoblasts. Forin vivostudy, our results indicated that ACAE inhibits bone loss and significantly increases percentage bone volume, trabecular bone number, and bone mineral density in OVX-SAMP8 mice treated with ACAE. Collectively,in vitroandin vivoresults showed that ACAE could promote osteogenesis and prevent bone loss and should be considered an evidence-based complementary and alternative medicine for osteoporosis therapy through the maintenance of bone health.

scholarly journals Semaphorin 3B Is a 1,25-Dihydroxyvitamin D3-Induced Gene in Osteoblasts that Promotes Osteoclastogenesis and Induces Osteopenia in Mice

2008 ◽  
Vol 22 (6) ◽  
pp. 1370-1381 ◽  
Author(s):  
Amelia L. M. Sutton ◽  
Xiaoxue Zhang ◽  
Diane R. Dowd ◽  
Yogendra P. Kharode ◽  
Barry S. Komm ◽  
...  
Keyword(s):  
Target Genes ◽  
Biological Effects ◽  
Osteoblastic Cells ◽  
Northern Analysis ◽  
Mineral Density ◽  
Dihydroxyvitamin D3 ◽  
1,25 Dihydroxyvitamin D3 ◽  
Skeletal Homeostasis

Abstract The vitamin D endocrine system is important for skeletal homeostasis. 1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] impacts bone indirectly by promoting intestinal absorption of calcium and phosphate and directly by acting on osteoblasts and osteoclasts. Despite the direct actions of 1,25(OH)2D3 in bone, relatively little is known of the mechanisms or target genes that are regulated by 1,25(OH)2D3 in skeletal cells. Here, we identify semaphorin 3B (SEMA3B) as a 1,25(OH)2D3-stimulated gene in osteoblastic cells. Northern analysis revealed strong induction of SEMA3B mRNA by 1,25(OH)2D3 in MG-63, ST-2, MC3T3, and primary osteoblastic cells. Moreover, differentiation of these osteogenic cells enhanced SEMA3B gene expression. Biological effects of SEMA3B in the skeletal system have not been reported. Here, we show that osteoblast-derived SEMA3B alters global skeletal homeostasis in intact animals and osteoblast function in cell culture. Osteoblast-targeted expression of SEMA3B in mice resulted in reduced bone mineral density and aberrant trabecular structure compared with nontransgenic littermates. Histomorphometry studies indicated that this was likely due to increased osteoclast numbers and activity. Indeed, primary osteoblasts obtained from SEMA3B transgenic mice stimulated osteoclastogenesis to a greater extent than nontransgenic osteoblasts. This study establishes that SEMA3B is a 1,25(OH)2D3-induced gene in osteoblasts and that osteoblast-derived SEMA3B impacts skeletal biology in vitro and in vivo. Collectively, these studies support a putative role for SEMA3B as an osteoblast protein that regulates bone mass and skeletal homeostasis.

scholarly journals Voxel size dependency, reproducibility and sensitivity of an in vivo bone loading estimation algorithm

2016 ◽  
Vol 13 (114) ◽  
pp. 20150991 ◽  
Author(s):  
Patrik Christen ◽  
Friederike A. Schulte ◽  
Alexander Zwahlen ◽  
Bert van Rietbergen ◽  
Stephanie Boutroy ◽  
...  
Keyword(s):  
Volume Fraction ◽  
Estimation Algorithm ◽  
Bone Volume ◽  
Micro Ct ◽  
Bone Volume Fraction ◽  
Voxel Size ◽  
Size Dependency ◽  
Bone Loading

A bone loading estimation algorithm was previously developed that provides in vivo loading conditions required for in vivo bone remodelling simulations. The algorithm derives a bone's loading history from its microstructure as assessed by high-resolution (HR) computed tomography (CT). This reverse engineering approach showed accurate and realistic results based on micro-CT and HR-peripheral quantitative CT images. However, its voxel size dependency, reproducibility and sensitivity still need to be investigated, which is the purpose of this study. Voxel size dependency was tested on cadaveric distal radii with micro-CT images scanned at 25 µm and downscaled to 50, 61, 75, 82, 100, 125 and 150 µm. Reproducibility was calculated with repeated in vitro as well as in vivo HR-pQCT measurements at 82 µm. Sensitivity was defined using HR-pQCT images from women with fracture versus non-fracture, and low versus high bone volume fraction, expecting similar and different loading histories, respectively. Our results indicate that the algorithm is voxel size independent within an average (maximum) error of 8.2% (32.9%) at 61 µm, but that the dependency increases considerably at voxel sizes bigger than 82 µm. In vitro and in vivo reproducibility are up to 4.5% and 10.2%, respectively, which is comparable to other in vitro studies and slightly higher than in other in vivo studies. Subjects with different bone volume fraction were clearly distinguished but not subjects with and without fracture. This is in agreement with bone adapting to customary loading but not to fall loads. We conclude that the in vivo bone loading estimation algorithm provides reproducible, sensitive and fairly voxel size independent results at up to 82 µm, but that smaller voxel sizes would be advantageous.

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