scholarly journals Prx1-Expressing Progenitor Primary Cilia Mediate Bone Formation in response to Mechanical Loading in Mice

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Emily R. Moore ◽  
Julia C. Chen ◽  
Christopher R. Jacobs
Keyword(s):  
Bone Formation ◽  
Mechanical Loading ◽  
Cell Population ◽  
Primary Cilia ◽  
Complete Response ◽  
Fracture Repair ◽  
Bone Tissue Regeneration ◽  
Attractive Alternative ◽  
Physical Stimulation

Increases in mechanical loading can enhance the addition of new bone, altering geometry and density such that bones better withstand higher forces. Bone-forming osteoblasts have long been thought to originate from progenitors, but the exact source is yet to be identified. Previous studies indicate osteogenic precursors arise from Prx1-expressing progenitors during embryonic development and adult fracture repair. However, it is unknown whether this cell population is also a source for mechanically induced active osteoblasts. We first identified that Prx1 is expressed in skeletally mature mouse periosteum, a thin tissue covering the surface of the bone that is rich in osteoprogenitors. We then traced Prx1 progenitor lineage using a transgenic mouse model carrying both a Prx1-driven tamoxifen-inducible Cre and a ROSA-driven lacZ reporter gene. Cells that expressed Prx1 when compressive axial loading was applied were detected within the cortical bone days after stimulation, indicating osteocytes are of Prx1-expressing cell origin. In addition, we evaluated how these cells sense and respond to physical stimulation in vivo by disrupting their primary cilia, which are antenna-like sensory organelles known to enhance mechanical and chemical signaling kinetics. Although Prx1-driven primary cilium disruption did not affect osteoblast recruitment to the bone surface, the relative mineral apposition and bone formation rates were decreased by 53% and 34%, respectively. Thus, this cell population contributes to load-induced bone formation, and primary cilia are needed for a complete response. Interestingly, Prx1-expressing progenitors are easily extracted from periosteum and are perhaps an attractive alternative to marrow stem cells for bone tissue regeneration strategies.

Ultrasound mimics the effect of mechanical loading on bone formation in vivo on rat ulnae

2009 ◽  
Vol 31 (1) ◽  
pp. 42-47 ◽  
Author(s):  
Mark J. Perry ◽  
Laura K. Parry ◽  
Victoria J. Burton ◽  
Sabina Gheduzzi ◽  
Jon N. Beresford ◽  
...  
Keyword(s):  
Bone Formation ◽  
Mechanical Loading

scholarly journals Combinatorial morphogenetic and mechanical cues to mimic bone development for defect repair

2019 ◽  
Author(s):  
S. Herberg ◽  
A. M. McDermott ◽  
P. N. Dang ◽  
D. S. Alt ◽  
R. Tang ◽  
...  
Keyword(s):  
Stem Cell ◽  
Bone Formation ◽  
Mechanical Loading ◽  
Endochondral Ossification ◽  
Bone Development ◽  
Human Mesenchymal Stem Cell ◽  
Bone Defects ◽  
Mechanical Environment ◽  
Tgf Β1

AbstractEndochondral ossification during long bone development and natural fracture healing initiates by mesenchymal cell condensation and is directed by local morphogen signals and mechanical cues. Here, we aimed to mimic these developmental conditions for regeneration of large bone defects. We hypothesized that engineered human mesenchymal stem cell (hMSC) condensations with in situ presentation of transforming growth factor-β1 (TGF-β1) and/or bone morphogenetic protein-2 (BMP-2) from encapsulated microparticles would promote endochondral regeneration of critical-sized rat femoral bone defects in a manner dependent on the in vivo mechanical environment. Mesenchymal condensations induced bone formation dependent on morphogen presentation, with dual BMP-2 + TGF-β1 fully restoring mechanical bone function by week 12. In vivo ambulatory mechanical loading, initiated at week 4 by delayed unlocking of compliant fixation plates, significantly enhanced the bone formation rate in the four weeks after load initiation in the dual morphogen group. In vitro, local presentation of either BMP-2 alone or BMP-2 + TGF-β1 initiated endochondral lineage commitment of mesenchymal condensations, inducing both chondrogenic and osteogenic gene expression through SMAD3 and SMAD5 signaling. In vivo, however, endochondral cartilage formation was evident only in the BMP-2 + TGF-β1 group and was enhanced by mechanical loading. The degree of bone formation was comparable to BMP-2 soaked on collagen but without the ectopic bone formation that limits the clinical efficacy of BMP-2/collagen. In contrast, mechanical loading had no effect on autograft-mediated repair. Together, this study demonstrates a biomimetic template for recapitulating developmental morphogenic and mechanical cues in vivo for tissue engineering.One Sentence SummaryMimicking aspects of the cellular, biochemical, and mechanical environment during early limb development, chondrogenically-primed human mesenchymal stem cell condensations promoted functional healing of critical-sized femoral defects via endochondral ossification, and healing rate and extent was a function of the in vivo mechanical environment.

Bioactive Glass Cloth that Promotes New Bone Formation

2012 ◽  
Vol 529-530 ◽  
pp. 266-269
Author(s):  
Tsutomu Minatoya ◽  
Toshitake Furusawa ◽  
Masaaki Sato ◽  
Yuta Matsushima ◽  
Hidero Unuma
Keyword(s):  
Bone Formation ◽  
Bioactive Glass ◽  
Glass Fibers ◽  
Bone Defects ◽  
Bone Tissue Regeneration ◽  
Porous Scaffolds ◽  
Glass Cloth ◽  
New Bone Formation ◽  
Made In

A new composition of bioactive glass was proposed that can be drawn into fibers, woven into cloth, and has appropriate alkali-releasing ability for bioactivity. The glass was drawn into fibers and woven into cloth, then the biological efficacy of the cloth was examined in in vivo tests. Bone defects made in tibial bones of Wistar rats were covered with the cloth just like "bandage" for two weeks. The cloth was found to promote new bone formation in the bone defects without causing any adverse effects. In contrast, excessive infection was recognized and new bone was not formed when cloth made of E-glass fibers was used. This was the first successful demonstration that glass cloth made of bioactive glass fibers assisted bone regeneration. The present glass cloth, therefore, is expected to be a promising material for "bone bandage" or porous scaffolds for bone tissue regeneration.

Bone Formation on Tissue-Engineered Cartilage Constructs in Vivo: Effects of Chondrocyte Viability and Mechanical Loading

2003 ◽  
Vol 9 (4) ◽  
pp. 587-596 ◽  
Author(s):  
Natasha D. Case ◽  
Angel O. Duty ◽  
Anthony Ratcliffe ◽  
Ralph Müller ◽  
Robert E. Guldberg
Keyword(s):  
Bone Formation ◽  
Mechanical Loading ◽  
Chondrocyte Viability ◽  
Engineered Cartilage ◽  
In Vivo Effects

scholarly journals Mechanical Loading Shows Anti-Myeloma Effects While Rescuing Bone Loss with Net Bone Formation in a Myeloma Bone Disease Murine Model

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 3164-3164
Author(s):  
Fani Ziouti ◽  
Maximilian Rummler ◽  
Andreas Brandl ◽  
Andreas Beilhack ◽  
Maureen Lynch ◽  
...  
Keyword(s):  
Bone Resorption ◽  
Bone Loss ◽  
Bone Formation ◽  
Bone Remodeling ◽  
Mechanical Loading ◽  
Bone Disease ◽  
Whole Body ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mechanical Stimuli

Abstract Osteolytic bone disease (BD) is a hallmark of multiple myeloma (MM) with tumor cells in the bone marrow shifting the balance of the bone remodeling process towards massive bone resorption. As a result, patients develop devastating osteolytic lesions that lead to non-healing bone fractures and pain, affecting life quality and mortality rates. Bones have the capacity to adapt mass and structure to mechanical stimuli, as dramatically seen in young tennis athletes with muscle-bone asymmetries in the playing arm. We have previously shown that tibial mechanical loading rescued bone loss in our murine MOPC315.BM MM model with an advanced osteolytic phenotype. Here, we hypothesize that mechanical strain (1) modulates the bone microenvironment and (2) has antitumor activity in mice. (1) We determined bone formation and bone resorption parameters by time-lapsed microCT analysis to show how skeletal mechanical stimuli control MM bone disease (MMBD) progression over time. (2) To monitor tumor progression, we used non-invasive bioluminescence imaging (BLI) and enzyme-linked immunosorbent assay (ELISA) for detection of MOPC315.BM specific immunoglobulin A (IgA) levels. In our in vivo loading study, we injected MOPC315.BM cells intratibially (i.t.) in BALB/c mice to establish MMBD (n=17) and used PBS-injected (n=13) as well as noninjected mice (n=8) as controls. Eight (MM), seven (PBS) and 8 (noninjected) mice received compressive tibial loading for three weeks while nine (MM) and six (PBS) mice served as nonloaded controls. The bone remodeling response to mechanical loading was investigated by longitudinal in vivo microCT imaging performed every 5 days (at day 13, 18, 23, 28, and 33 after i.t. injection). MicroCT images from day 33 were geometrically registered onto images of day 13 and resampled into the same coordinate system using Amira and scripts written in Matlab for post-processing. Normalized newly mineralized and eroded bone volume (MV/BV, EV/BV), normalized formed and eroded bone surface area (MS/BS, ES/BS), mineralized thickness (MTh) and eroded depth (ED) were quantified. ANOVA was performed to examine the effect of loading and injection. Loading significantly increased the periosteal MV/BV, periosteal and endosteal MS/BS as well as decreased the periosteal EV/BV and periosteal and endocortical ES/BS. Endosteal MV/BV or EV/BV were not affected, which may be due to differences in the local strain environment at the two surfaces. In addition, mechanical stimuli did not influence ED, but led to diminished periosteal EV/BV and periosteal ES/BS suggesting fewer resorption sites in tibiae subjected to loading. Injection significantly affected periosteal and endosteal bone formation and resorption (Fig.1). Significant increases in cortical bone mass of loaded MM mice were accompanied by decreases in tumor load as evidenced by MOPC315.BM specific IgA levels (Fig. 2A). Interestingly, quantification of tibial and whole body bioluminescence signal intensities revealed controlled tumor growth in the loaded left tibia and a further delay of tumor cell dissemination throughout body of MM mice (Fig. 2B). Our data provide evidence that skeletal mechanical stimuli have anti-myeloma effects and rescue osteolytic bone loss in MMBD. The anabolic response to mechanical loads outweighs the anti-resorptive effect of MM cells, suggesting a combination of loading with bone resorption inhibitors in future therapeutic strategies. Disclosures No relevant conflicts of interest to declare.

Bone regeneration strategy by different sized multichanneled biphasic calcium phosphate granules: In vivo evaluation in rabbit model

2018 ◽  
Vol 32 (10) ◽  
pp. 1406-1420 ◽  
Author(s):  
Mirana Taz ◽  
Sang Ho Bae ◽  
Hae Il Jung ◽  
Hyun-Deuk Cho ◽  
Byong-Taek Lee
Keyword(s):  
Calcium Phosphate ◽  
Bone Formation ◽  
Rabbit Model ◽  
Morphological Characteristics ◽  
Confocal Imaging ◽  
Bone Tissue Regeneration ◽  
Micro Computed Tomography ◽  
In Vivo Evaluation

A variety of synthetic materials are currently in use as bone substitutes, among them a new calcium phosphate-based multichannel, cylindrical, granular bone substitute that is showing satisfactory biocompatibility and osteoconductivity in clinical applications. These cylindrical granules differ in their mechanical and morphological characteristics such as size, diameter, surface area, pore size, and porosity. The aim of this study is to investigate whether the sizes of these synthetic granules and the resultant inter-granular spaces formed by their filling critical-sized bone defects affect new bone formation characteristics and to determine the best formulations from these individual types by combining the granules in different proportions to optimize the bone tissue regeneration. We evaluated two types of multichanneled cylindrical granules, 1 mm and 3 mm in diameter, combined the granules in two different proportions (wt%), and compared their different mechanical, morphological, and in vitro and in vivo biocompatibility characteristics. We assessed in vitro biocompatibility and cytotoxicity using MC3T3-E1 osteoblast-like cells using MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and confocal imaging. In vivo investigation in a rabbit model indicated that all four samples formed significantly better bone than the control after four weeks and eight weeks of implantation. Micro-computed tomography analysis showed more bone formation by the 1 mm cylindrical granules with 160 ± 10 µm channeled pore and 50% porosity than the other three samples ( p<.05), which we confirmed by histological analysis.

scholarly journals Disruption of Dhcr7 and Insig1/2 in cholesterol metabolism causes defects in bone formation and homeostasis through primary cilium formation

Bone Research ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Akiko Suzuki ◽  
Kenichi Ogata ◽  
Hiroki Yoshioka ◽  
Junbo Shim ◽  
Christopher A. Wassif ◽  
...  
Keyword(s):  
Bone Formation ◽  
Primary Cilium ◽  
Hedgehog Signaling ◽  
Primary Cilia ◽  
Cholesterol Metabolism ◽  
Cholesterol Biosynthesis ◽  
Cilium Formation ◽  
Intracellular Cholesterol

AbstractHuman linkage studies suggest that craniofacial deformities result from either genetic mutations related to cholesterol metabolism or high-cholesterol maternal diets. However, little is known about the precise roles of intracellular cholesterol metabolism in the development of craniofacial bones, the majority of which are formed through intramembranous ossification. Here, we show that an altered cholesterol metabolic status results in abnormal osteogenesis through dysregulation of primary cilium formation during bone formation. We found that cholesterol metabolic aberrations, induced through disruption of either Dhcr7 (which encodes an enzyme involved in cholesterol synthesis) or Insig1 and Insig2 (which provide a negative feedback mechanism for cholesterol biosynthesis), result in osteoblast differentiation abnormalities. Notably, the primary cilia responsible for sensing extracellular cues were altered in number and length through dysregulated ciliary vesicle fusion in Dhcr7 and Insig1/2 mutant osteoblasts. As a consequence, WNT/β-catenin and hedgehog signaling activities were altered through dysregulated primary cilium formation. Strikingly, the normalization of defective cholesterol metabolism by simvastatin, a drug used in the treatment of cholesterol metabolic aberrations, rescued the abnormalities in both ciliogenesis and osteogenesis in vitro and in vivo. Thus, our results indicate that proper intracellular cholesterol status is crucial for primary cilium formation during skull formation and homeostasis.

scholarly journals NGF-TrkA signaling in sensory nerves is required for skeletal adaptation to mechanical loads in mice

2017 ◽  
Vol 114 (18) ◽  
pp. E3632-E3641 ◽  
Author(s):  
Ryan E. Tomlinson ◽  
Zhi Li ◽  
Zhu Li ◽  
Liliana Minichiello ◽  
Ryan C. Riddle ◽  
...  
Keyword(s):  
Bone Formation ◽  
Mechanical Loading ◽  
Mechanical Stretch ◽  
Early Response ◽  
Sensory Nerves ◽  
Wild Type ◽  
Maximal Load ◽  
Skeletal Adaptation

Sensory nerves emanating from the dorsal root extensively innervate the surfaces of mammalian bone, a privileged location for the regulation of biomechanical signaling. Here, we show that NGF-TrkA signaling in skeletal sensory nerves is an early response to mechanical loading of bone and is required to achieve maximal load-induced bone formation. First, the elimination of TrkA signaling in mice harboring mutant TrkAF592A alleles was found to greatly attenuate load-induced bone formation induced by axial forelimb compression. Next, both in vivo mechanical loading and in vitro mechanical stretch were shown to induce the profound up-regulation of NGF in osteoblasts within 1 h of loading. Furthermore, inhibition of TrkA signaling following axial forelimb compression was observed to reduce measures of Wnt/β-catenin activity in osteocytes in the loaded bone. Finally, the administration of exogenous NGF to wild-type mice was found to significantly increase load-induced bone formation and Wnt/β-catenin activity in osteocytes. In summary, these findings demonstrate that communication between osteoblasts and sensory nerves through NGF-TrkA signaling is essential for load-induced bone formation in mice.

scholarly journals 2010 Use it but still lose it: Exploring age-related changes in skeletal stem cell location and activation in response to physical stimulation

2018 ◽  
Vol 2 (S1) ◽  
pp. 35-35
Author(s):  
Pamela C. Zuckerman ◽  
Chao Liu ◽  
Alesha B. Castillo
Keyword(s):  
Mechanical Loading ◽  
Cell Population ◽  
Cell Number ◽  
Medial Region ◽  
Physical Stimulation ◽  
Aged Mice ◽  
Adult Mice ◽  
Age Related ◽  
Periosteal Cell ◽  
Periosteal Cells

OBJECTIVES/SPECIFIC AIMS: Our goal is to assess age-related changes in osteogenic stem cell populations of bone tissue. We hypothesize that aging mice have reduced osteogenic capacity in response to physical stimulation due to aging-associated decline in osteoprogenitor cell number and their proliferative capacity. METHODS/STUDY POPULATION: Mechanical loading: The NYU School of Medicine Institutional Animal Care and Use Committee approved all procedures. The response of tibial periosteal cells to physical stimulation or mechanical loading was assessed in 16-week-old adult (n=6) and aged 78-week-old female (n=4) mice subjected to 4 consecutive days of strain-matched axial compressive loading (1400 μm, 120 cycles, 2 Hz). Whole Mount Staining: Baseline periosteal cell numbers and nuclear morphology were assessed by whole bone DAPI staining of the antero-medial region of the tibiae in adult and aged mice (n=6). Immunohistochemistry: Tibiae were fixed in 4% PFA, decalcified in 19% EDTA, OCT-embedded, and thickly sectioned (150 μm) at midshaft. Sca1+, Prrx1+, and Ki67+cell numbers were quantified by simultaneous fluorescent immunohistochemical staining from loaded and nonloaded contralateral tibiae. Nonimmune species specific serum served as negative controls. Imaging: 3D image datasets of the periosteum at the antero-medial region of the tibial midshaft were acquired by multi-photon and confocal microscopy. Quantification of Sca1+, Prrx1+, and Ki67+ cells was carried out using Particle Analysis software (ImageJ) and Imaris 7.4.2 Surface Rendering Statistics functions. Cell number was normalized to periosteal area (~0.04 mm2). A Student t-test determined significance at p<0.05. RESULTS/ANTICIPATED RESULTS: At baseline, aged periosteal cell nuclei (DAPI+) area (14% decrease, p<0.0001), nuclei number, and Prrx1+ cell number (22% decrease) was significantly lower compared with adult mice. In loaded adult mice, Prrx1+but not Sca1+cell number increased significantly (35%, p=0.0115). Proliferating Sca1+(top panel) and Prrx1+(top panel) cells also increased with loading, 62%, p=0.0253 and 115%, p=0.0004, respectively, in adult but not aged mice. The percentage of Prrx1+ cells undergoing proliferation (co-expressing Ki67+) in the total Prrx1+ cell population increased significantly with loading (bottom panel). Aged mice did not exhibit significant differences in loaded versus nonloaded controls for all other outcomes. Our data suggest fundamental changes in periosteal cell morphology, number and response to mechanical loading with aging. The significant increase in total Prrx1+ cell number and the number of Prrx1+ cells undergoing proliferation with loading in adult mice, suggest that the Prrx1+ cell population expands through proliferation. In fact, loading resulted in a 2-fold increase in the percentage of Prrx1+ preosteogenic cells undergoing proliferation. Accordingly, the significant age-related decrease in Prrx1+ cells may explain, in part, the attenuation of load-induced bone formation in aged mice. Loading resulted in greater numbers of proliferating Sca1+ cells (the more primitive cell) in adult mice, though this represented only a small percentage (<10%) of the total Sca1+ population. Mechanical loading expands the Prrx1+ pre-osteogenic cell population, but not the more primitive Sca1+ population. However, this load-induced osteogenic effect in the periosteum is not observed in aged mice, which may explain age-related diminishment of load-induced bone formation. DISCUSSION/SIGNIFICANCE OF IMPACT: Mechanical loading presents an inexpensive treatment for increasing bone mass and bone strength, but may be insufficient to prevent or reverse age-related bone loss due to reduced numbers of osteogenic progenitors in the periosteum. Therapeutic approaches targeting the osteogenic capacity of periosteal cells will be required to address declining mechanoresponsiveness with age.

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