The mechanosensitive Piezo1 orchestrating angiogenesis is essential in bone fracture repair

AbstractMechanical ion channel protein Piezo1 play vital roles in angiogenesis which has been proved to be high importance in varieties of biological processes. Bone formation in the fracture repair requires oxygen and nutrients from new blood vessels generated from fractured lesion. Understanding the underlying mechanisms linking angiogenesis and bone formation must be of great value for improved fracture healing. Here we employed mice with genetically modified endothelial specific depletion of Piezo1 channels to explore the hypothesis that Piezo1 is vital to the initiation of fracture healing. In this study, we demonstrated that Piezo1 expression and wide distribution along the bone and impaired endothelial Piezo1 channels result in derangements in bone fracture repair. Intriguingly, the calcium activated proteolytic caplain activity severely disrupted during vascularization, precluded osteoblast maturation and mineralization and subsequently the phosphorylated PI3K-AKT reduction. Furthermore, Piezo1 endothelial disruption impaired Notch signaling in bone union. These data collectively suggest that Piezo1 channels serve as a basis for clinical strategies to improve bone regeneration and treat delayed or nonunion in bone fracture.

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YAP and TAZ promote periosteal osteoblast precursor expansion and differentiation for fracture repair

10.1101/2020.03.17.995761 ◽

2020 ◽

Cited By ~ 1

Author(s):

Christopher D. Kegelman ◽

Madhura P. Nijsure ◽

Yasaman Moharrer ◽

Hope B. Pearson ◽

James H. Dawahare ◽

...

Keyword(s):

Bone Formation ◽

Fracture Healing ◽

Bone Fracture ◽

Callus Formation ◽

Fracture Repair ◽

Binding Motif ◽

Adult Onset ◽

Bone Fracture Healing ◽

Fracture Callus ◽

Endochondral Bone

ABSTRACTIn response to bone fracture, periosteal progenitor cells proliferate, expand, and differentiate to form cartilage and bone in the fracture callus. These cellular functions require the coordinated activation of multiple transcriptional programs, and the transcriptional regulators Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) regulate osteochondroprogenitor activation during endochondral bone development. However, recent observations raise important distinctions between the signaling mechanisms used to control bone morphogenesis and repair. Here, we tested the hypothesis that YAP and TAZ regulate osteochondroprogenitor activation during endochondral bone fracture healing. Constitutive YAP and/or TAZ deletion from Osterix-expressing cells impaired both cartilage callus formation and subsequent mineralization. However, this could be explained either by direct defects in osteochondroprogenitor differentiation after fracture, or by developmental deficiencies in the progenitor cell pool prior to fracture. Consistent with the second possibility, we found that developmental YAP/TAZ deletion produced long bones with impaired periosteal thickness and cellularity. Therefore, to remove the contributions of developmental history, we next generated adult onset-inducible knockout mice (using Osx1-CretetOff) in which YAP and TAZ were deleted prior to fracture, but after normal development. Adult onset-induced YAP/TAZ deletion had no effect on cartilaginous callus formation, but impaired bone formation at 14 days post-fracture (dpf). Earlier, at 4 dpf, adult onset-induced YAP/TAZ deletion impaired the proliferation and expansion of osteoblast precursor cells located in the shoulder of the callus. Further, activated periosteal cells isolated from this region at 4 dpf exhibited impaired osteogenic differentiation in vitro upon YAP/TAZ deletion. Finally, confirming the effects on osteoblast function in vivo, adult onset-induced YAP/TAZ deletion impaired bone formation in the callus shoulder at 7 dpf, prior to the initiation of endochondral ossification. Together, these data show that YAP and TAZ promote the expansion and differentiation of periosteal osteoblast precursors to accelerate bone fracture healing.

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Histone demethylase LSD1 is critical for endochondral ossification during bone fracture healing

Science Advances ◽

10.1126/sciadv.aaz1410 ◽

2020 ◽

Vol 6 (45) ◽

pp. eaaz1410

Author(s):

Jun Sun ◽

Heng Feng ◽

Wenhui Xing ◽

Yujiao Han ◽

Jinlong Suo ◽

...

Keyword(s):

Retinoic Acid ◽

Fracture Healing ◽

Bone Regeneration ◽

Bone Fracture ◽

Endochondral Ossification ◽

Callus Formation ◽

Critical Factor ◽

Fracture Repair ◽

Retinoic Acid Signaling ◽

Bone Fracture Healing

Bone fracture is repaired predominantly through endochondral ossification. However, the regulation of endochondral ossification by key factors during fracture healing remains largely enigmatic. Here, we identify histone modification enzyme LSD1 as a critical factor regulating endochondral ossification during bone regeneration. Loss of LSD1 in Prx1 lineage cells severely impaired bone fracture healing. Mechanistically, LSD1 tightly controls retinoic acid signaling through regulation of Aldh1a2 expression level. The increased retinoic acid signaling in LSD1-deficient mice suppressed SOX9 expression and impeded the cartilaginous callus formation during fracture repair. The discovery that LSD1 can regulate endochondral ossification during fracture healing will benefit the understanding of bone regeneration and have implications for regenerative medicine.

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Conditioned media from endothelial progenitor cells cultured in simulated microgravity promote angiogenesis and bone fracture healing

Stem Cell Research & Therapy ◽

10.1186/s13287-020-02074-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Lingchi Kong ◽

Yan Wang ◽

Haixing Wang ◽

Qi Pan ◽

Rongtai Zuo ◽

...

Keyword(s):

Fracture Healing ◽

Progenitor Cells ◽

Endothelial Progenitor Cells ◽

Bone Fracture ◽

Mechanical Test ◽

Human Peripheral Blood ◽

Mapk Signaling ◽

Fracture Repair ◽

Conditioned Media ◽

Endothelial Progenitor

Abstract Background Paracrine signaling from endothelial progenitor cells (EPCs) is beneficial for angiogenesis and thus promotes tissue regeneration. Microgravity (MG) environment is found to facilitate the functional potentials of various stem or progenitor cells. The present study aimed to elucidate the effects of MG on pro-angiogenic properties and fracture repair capacities of conditioned media (CM) from EPCs. Methods Human peripheral blood-derived EPCs were cultured under MG or normal gravity (NG) followed by analysis for angiogenic gene expression. Furthermore, the serum-free CM under MG (MG-CM) or NG (NG-CM) were collected, and their pro-angiogenic properties were examined in human umbilical vein endothelial cells (HUVECs). In order to investigate the effects of MG-CM on fracture healing, they were injected into the fracture gaps of rat models, and radiography, histology, and mechanical test were performed to evaluate neovascularization and fracture healing outcomes. Results MG upregulated the expression of hypoxia-induced factor-1α (HIF-1α) and endothelial nitric oxide synthase (eNOS) and promoted NO release. Comparing to NG-CM, MG-CM significantly facilitated the proliferation, migration, and angiogenesis of HUVECs through NO-induced activation of FAK/Erk1/2-MAPK signaling pathway. In addition, MG-CM were verified to improve angiogenic activities in fracture area in a rat tibial fracture model, accelerate fracture healing, and well restore the biomechanical properties of fracture bone superior to NG-CM. Conclusion These findings provided insight into the use of MG bioreactor to enhance the angiogenic properties of EPCs’ paracrine signals via HIF-1α/eNOS/NO axis, and the administration of MG-CM favored bone fracture repair. Graphical abstract

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A Coupled Computational Framework for Bone Fracture Healing and Long-term Remodelling: Investigating the Role of Internal Fixation on Bone Fractures

10.31224/osf.io/e36ba ◽

2021 ◽

Author(s):

Conall Quinn ◽

Alexander Kopp ◽

Ted J Vaughan

Keyword(s):

Internal Fixation ◽

Fracture Healing ◽

Bone Fracture ◽

Bone Fractures ◽

Computational Modelling ◽

Fracture Repair ◽

Time Averaging ◽

Fixation Devices

In this study, a coupled computational modelling framework for bone fracture repair is presented that enables predictions of both healing and remodelling phases of the fracture region and is used to investigate the role of an internal fixation plate on the long-term healing performance of a fracture tibia under a range of different conditions. It was found that introduction of a titanium plate allowed the tibia to undergo successful healing at higher loading conditions and fracture gaps, compared to the non-plated versions. While these plated cases showed faster rates of repair in the healing phase, their performance was substantially different once they entered the remodelling phase, with substan-tial regions of stress shielding predicted. This framework is one of the few im-plementations of both fracture healing and remodelling phases of bone repair and includes several innovative approaches to smoothing, time-averaging and time incrementation in its implementation, thereby avoiding any unwanted abrupt changes between tissue phenotypes. This provides a better representa-tion of tissue development in the fracture site when compared to fracture healing models alone and provides a suitable platform to investigate the long-term performance of orthopaedic fixation devices. This would enable the more effective design of permanent fixation devices and optimisation of the spatial and temporal performance of bioabsorbable implants

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Bioinformatics Analysis of the Molecular Mechanism of Aging on Fracture Healing

BioMed Research International ◽

10.1155/2018/7530653 ◽

2018 ◽

Vol 2018 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Shu-Jie Zhao ◽

Fan-Qi Kong ◽

Jin Fan ◽

Ying Chen ◽

Shuai Zhou ◽

...

Keyword(s):

Fracture Healing ◽

Bone Fracture ◽

Wnt Signaling Pathway ◽

The Elderly ◽

Gene Expression Omnibus ◽

Fracture Repair ◽

Ppi Network ◽

Network Analyses ◽

Delayed Fracture Healing ◽

Effects Of Aging

Increasing age negatively affects different phases of bone fracture healing. The present study aimed to explore underlying mechanisms related to bone fracture repair in the elderly. GSE17825 public transcriptome data from the Gene Expression Omnibus database were used for analysis. First, raw data were normalized and differentially expressed genes (DEGs) were identified. Next, Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were implemented to evaluate pathways and DEGs. A protein–protein interaction (PPI) network was then constructed. A total of 726, 861, and 432 DEGs were identified between the young and elderly individuals at 1, 3, and 5 days after fracture, respectively. The results of GO, KEGG, and PPI network analyses suggested that the inflammatory response, Wnt signaling pathway, vascularization-associated processes, and synaptic-related functions of the identified DEGs are markedly enriched, which may account for delayed fracture healing in the elderly. These findings provide valuable clues for investigating the effects of aging on fracture healing but should be validated through further experiments.

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Elevated concentrations of hypoxia-inducible factor-1α in patients with fracture and concomitant traumatic brain injury

Annals of Clinical Biochemistry International Journal of Laboratory Medicine ◽

10.1177/0004563216673087 ◽

2016 ◽

Vol 54 (5) ◽

pp. 584-592 ◽

Cited By ~ 1

Author(s):

Xiguang Sang ◽

Zhiyong Wang ◽

Tao Qin ◽

Yonggang Li

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

Fracture Healing ◽

Bone Fracture ◽

Hypoxia Inducible Factor ◽

Fracture Repair ◽

Long Bone ◽

Enzyme Linked Immunosorbent Assay ◽

Serum Samples ◽

Hypoxia Inducible Factor 1Α

Background Compelling evidence indicate that traumatic brain injury is highly related to accelerated bone fracture repair, but the underlying mechanism still remains elusive. Fracture repair process relies greatly on the formation of new blood vessels in fracture site, and angiogenic factors have been confirmed to be essential for the initiation and maintenance of the fracture healing. Hypoxia-inducible factor-1α was demonstrated to be a critical regulator of angiogenic–osteogenic coupling during bone development and regeneration. The aim of the present study was to investigate the local and circulating concentrations of hypoxia-inducible factor-1α in patients with long-bone fractures and concomitant traumatic brain injury and to determine the potential role of hypoxia-inducible factor-1α in fracture healing. Methods Twenty-five patients with a long-bone fracture and concomitant traumatic brain injury (FT group) and 33 without a brain injury (Fr group) were enrolled in this study. Healthy subjects donated serum samples as control. Serum samples were collected over a period of six months, following a standardized time schedule. Hypoxia-inducible factor-1α concentrations were measured in fracture haematoma and serum of patients in both groups using enzyme-linked immunosorbent assay. Results Patients in FT group had a short time to union. Serum hypoxia-inducible factor-1α concentrations elevated in the early healing period and reached the maximum level during intramembranous bone formation phase in both groups. Thereafter, it decreased continuously and approached to the minimum levels until the end of the observation period. Serum hypoxia-inducible factor-1α concentrations in both groups were significantly higher compared with controls and hypoxia-inducible factor-1α concentrations in both serum and fracture haematoma were higher in FT group than that in Fr group. Fracture haematoma contained significantly higher hypoxia-inducible factor-1α concentrations compared with hypoxia-inducible factor-1α concentrations in serum. Serum hypoxia-inducible factor-1α concentrations had a positive correlation with hypoxia-inducible factor-1α concentrations in fracture haematoma in patients with fractures. Conclusions These findings suggest the local and systemic involvement of hypoxia-inducible factor-1α in fracture healing and the accelerated fracture repair in patients with traumatic brain injury might be associated with elevated hypoxia-inducible factor-1α concentrations in fracture haematoma and serum.

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PHOSPHO1 is essential for normal bone fracture healing

Bone and Joint Research ◽

10.1302/2046-3758.76.bjr-2017-0140.r2 ◽

2018 ◽

Vol 7 (6) ◽

pp. 397-405 ◽

Cited By ~ 7

Author(s):

M. W. Morcos ◽

H. Al-Jallad ◽

J. Li ◽

C. Farquharson ◽

J. L. Millán ◽

...

Keyword(s):

Fracture Healing ◽

Bone Fracture ◽

Healing Process ◽

Bone Volume ◽

Fracture Repair ◽

Bending Test ◽

Bone Fracture Healing ◽

Trabecular Thickness ◽

Three Point Bending ◽

Normal Bone

Objectives Bone fracture healing is regulated by a series of complex physicochemical and biochemical processes. One of these processes is bone mineralization, which is vital for normal bone development. Phosphatase, orphan 1 (PHOSPHO1), a skeletal tissue-specific phosphatase, has been shown to be involved in the mineralization of the extracellular matrix and to maintain the structural integrity of bone. In this study, we examined how PHOSPHO1 deficiency might affect the healing and quality of fracture callus in mice. Methods Tibial fractures were created and then stabilized in control wild-type (WT) and Phospho1-/- mice (n = 16 for each group; mixed gender, each group carrying equal number of male and female mice) at eight weeks of age. Fractures were allowed to heal for four weeks and then the mice were euthanized and their tibias analyzed using radiographs, micro-CT (μCT), histology, histomorphometry and three-point bending tests. Results The μCT and radiographic analyses revealed a mild reduction of bone volume in Phospho1-/- callus, although it was not statistically significant. An increase in trabecular number and a decrease in trabecular thickness and separation were observed in Phospho1-/- callus in comparison with the WT callus. Histomorphometric analyses showed that there was a marked increase of osteoid volume over bone volume in the Phospho1-/- callus. The three-point bending test showed that Phospho1-/- fractured bone had more of an elastic characteristic than the WT bone. Conclusion Our work suggests that PHOSPHO1 plays an integral role during bone fracture repair and may be a therapeutic target to improve the fracture healing process. Cite this article: M. W. Morcos, H. Al-Jallad, J. Li, C. Farquharson, J. L. Millán, R. C. Hamdy, M. Murshed. PHOSPHO1 is essential for normal bone fracture healing: An Animal Study. Bone Joint Res 2018;7:397–405. DOI: 10.1302/2046-3758.76.BJR-2017-0140.R2.

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Apigenin promotes osteogenic differentiation of mesenchymal stem cells and accelerates bone fracture healing via activating Wnt/β-catenin signaling

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00543.2019 ◽

2021 ◽

Author(s):

Fei-fei Pan ◽

Jiang Shao ◽

Chuan-jian Shi ◽

Zhi-peng Li ◽

Wei-ming Fu ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Fracture Healing ◽

Osteogenic Differentiation ◽

Bone Fracture ◽

Fruits And Vegetables ◽

Target Genes ◽

Fracture Repair

Apigenin (API), a natural plant flavone, is abundantly found in common fruits and vegetables. As a bioactive flavonoid, API exhibits several activities including anti-proliferation and anti-inflammation. A recent study showed that API could retard osteoporosis progress, indicating its role in the skeletal system. However, the detailed function and mechanism remain obscure. In the present study, API was found to promote osteogenic differentiation of mesenchymal stem cells (MSCs). And further investigation showed that API could enhance the expression of the critical transcription factor β-catenin and several downstream target genes of Wnt signaling, thus activated Wnt/β-catenin signaling. Using a rat femoral fracture model, API was found to improve new bone formation and accelerate fracture healing in vivo. In conclusion, our data demonstrated that API could promote osteogenesis in vitro and facilitate the fracture healing in vivo via activating Wnt/β-catenin signaling, indicating that API may be a promising therapeutic candidate for bone fracture repair.

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Troxerutin Stimulates Osteoblast Differentiation of Mesenchymal Stem Cell and Facilitates Bone Fracture Healing

Frontiers in Pharmacology ◽

10.3389/fphar.2021.723145 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xiao Yang ◽

Jiang Shao ◽

Xiao-Min Wu ◽

Fei-Fei Pan ◽

Shao-An Yang ◽

...

Keyword(s):

Fracture Healing ◽

Bone Fracture ◽

Target Genes ◽

Fracture Repair ◽

Marker Genes ◽

Nodule Formation ◽

Dependent Manner ◽

Concentration Dependent Manner

Troxerutin (TRX), a semi-synthetic derivative of the natural bioflavonoid rutin, is a bioactive flavonoid widely abundant in various fruits and vegetables. Known as vitamin P4, TRX has been demonstrated to have several activities including anti-inflammation, anti-oxidants, vasoprotection, and immune support in various studies. Although rutin, the precursor of troxerutin, was reported to have a protective role against bone loss, the function of TRX in skeletal system remains unknown. In the present study, we found that TRX promoted osteogenic differentiation of human mesenchymal stem cells (MSCs) in a concentration-dependent manner by stimulating the alkaline phosphatase (ALP) activity, calcium nodule formation and osteogenic marker genes expression in vitro. The further investigation demonstrated that TRX stimulated the expression of the critical transcription factor β-catenin and several downstream target genes of Wnt signaling, thus activated Wnt/β-catenin signaling. Using a femur fracture rats model, TRX was found to stimulate new bone formation and accelerate the fracture healing in vivo. Collectively, our data demonstrated that TRX could promote osteogenesis in vitro and facilitate the fracture healing in vivo, indicating that TRX may be a promising therapeutic candidate for bone fracture repair.

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Analysis of osteoblast, osteoclast levels and radiographic patterns in the healing process of bone fractures (preliminary research)

Jurnal Radiologi Dentomaksilofasial Indonesia ◽

10.32793/jrdi.v5i3.740 ◽

2021 ◽

Vol 5 (3) ◽

pp. 106

Author(s):

Norlaila Sarifah ◽

Lusi Epsilawati ◽

Azhari Azhari ◽

Mieke Hermiawati Satari ◽

Bambang Pontjo Priosoeryanto ◽

...

Keyword(s):

Bone Resorption ◽

Bone Formation ◽

Fracture Healing ◽

Bone Fracture ◽

Bone Fractures ◽

Callus Formation ◽

Healing Process ◽

Lateral Position ◽

Original Structure ◽

Male Wistar Rats

Objectives: The healing process of a bone fracture goes through many phases. The hard callus phase was critical where the original structure was conducted. The hard callus growth depends on osteoblasts and osteoclasts active, and this condition can be analyzed on the radiograph. This study aimed to examine the analysis of bone fracture healing between osteoblasts and osteoclast numbers and radiographic patterns. Materials and Methods: The study used 12 male Wistar rats with an incomplete fracture in the right femur made by a dental tapered bur with 0.3 mm in length and 0.2 mm in depth. Digital radiographic examinations were carried out on days 0, 5, 10, 17, and 25 after fracturing in a lateral position. Furthermore, a radiographic analysis was performed using Image-J to obtain changes in the value of length and depth in the healing area. The research was conducted to find the radiopaque and radiolucent patterns and the number of osteoblasts and osteoclasts. Results: This study resulted in a change in the radiograph pattern. Callus formation resulted in fracture areas with a smaller distance from day 0 to day 25. The bone healing process begins with granulation tissue formation, followed by the gradual replacement of the connective tissue and bone. This process is comparable to the increase in osteoblasts up to day 25, which blocks bone resorption. Osteoclasts regulate bone resorption, and their number increases after 10 and 17 days to replace bone formation. Osteoclasts decline after 25 days because osteoblasts inhibit them, which control bone formation. Conclusion: The conclusions were obtained there are changes in the radiograph pattern. The radiopaque increased while the radiolucent decreased; the osteoclast pattern tended to be stable and lowered while the osteoblasts increased during the fracture healing process. The correlation of all the factors is very closely related.

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