scholarly journals Bone Morphogenetic Proteins Stimulate Angiogenesis through Osteoblast-Derived Vascular Endothelial Growth Factor A

Endocrinology ◽  
2002 ◽  
Vol 143 (4) ◽  
pp. 1545-1553 ◽  
Author(s):  
Martine M. L. Deckers ◽  
Rutger L. van Bezooijen ◽  
Geertje van der Horst ◽  
Jakomijn Hoogendam ◽  
Chris van der Bent ◽  
...  

Abstract During bone formation and fracture healing there is a cross-talk between endothelial cells and osteoblasts. We previously showed that vascular endothelial growth factor A (VEGF-A) might be an important factor in this cross-talk, as osteoblast-like cells produce this angiogenic factor in a differentiation-dependent manner. Moreover, exogenously added VEGF-A enhances osteoblast differentiation. In the present study we investigated, given the coupling between angiogenesis and bone formation, whether bone morphogenetic proteins (BMPs) stimulate osteoblastogenesis and angiogenesis through the production of VEGF-A. For this we used the murine preosteoblast-like cell line KS483, which forms mineralized nodules in vitro, and an angiogenesis assay comprising 17-d-old fetal mouse bone explants that have the ability to form tube-like structures in vitro. Treatment of KS483 cells with BMP-2, -4, and -6 enhanced nodule formation, osteocalcin mRNA expression, and subsequent mineralization after 18 d of culture. This was accompanied by a dose-dependent increase in VEGF-A protein levels throughout the culture period. BMP-induced osteoblast differentiation, however, was independent of VEGF-A, as blocking VEGF-A activity by a VEGF-A antibody or a VEGF receptor 2 tyrosine kinase inhibitor did not affect BMP-induced mineralization. To investigate whether BMPs stimulate angiogenesis through VEGF-A, BMPs were assayed for their angiogenic activity. Treatment of bone explants with BMPs enhanced angiogenesis. This was inhibited by soluble BMP receptor 1A or noggin. In the presence of a VEGF-A antibody, both unstimulated and BMP-stimulated angiogenesis were arrested. Conditioned media of KS483 cells treated with BMPs also induced a strong angiogenic response, which was blocked by antimouse VEGF-A but not by noggin. These effects were specific for BMPs, as TGFβ inhibited osteoblast differentiation and angiogenesis while stimulating VEGF-A production. These findings indicate that BMPs stimulate angiogenesis through the production of VEGF-A by osteoblasts. In conclusion, VEGF-A produced by osteoblasts in response to BMPs is not involved in osteoblast differentiation, but couples angiogenesis to bone formation.

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Bo Li ◽  
Hai Wang ◽  
Guixing Qiu ◽  
Xinlin Su ◽  
Zhihong Wu

Vascular endothelial growth factor (VEGF) and bone morphogenetic proteins (BMPs), as key mediators in angiogenesis and osteogenesis, are used in a combined delivery manner as a novel strategy in bone tissue engineering. VEGF has the potential to enhance BMPs induced bone formation. Both gene delivery and material-based delivery systems were incorporated in previous studies to investigate the synergistic effects of VEGF and BMPs. However, their results were controversial due to variation of methods incorporated in different studies. Factors influencing the synergistic effects of VEGF on BMPs induced bone formation were identified and analyzed in this review to reduce confusion on this issue. The potential mechanisms and directions of future studies were also proposed here. Further investigating mechanisms of the synergistic effects and optimizing these influencing factors will help to generate more effective bone regeneration.


2016 ◽  
Vol 397 (8) ◽  
pp. 765-775 ◽  
Author(s):  
Chang-jun Pi ◽  
Kai-lu Liang ◽  
Zhen-yong Ke ◽  
Fu Chen ◽  
Yun Cheng ◽  
...  

Abstract Mesenchymal stem cells (MSCs) are suitable seed cells for bone tissue engineering because they can self-renew and undergo differentiation into osteogenic, adipogenic, chondrogenic, or myogenic lineages. Vascular endothelial growth factor-a (VEGF-a), an angiogenic factor, is also involved in osteogenesis and bone repair. However, the effects of VEGF-a on osteogenic MSCs differentiation remain unknown. It was previously reported that bone morphogenetic protein9 (BMP9) is one of the most important osteogenic BMPs. Here, we investigated the effects of VEGF-a on BMP9-induced osteogenesis with mouse embryo fibroblasts (MEFs). We found that endogenous VEGF-a expression was undetectable in MSCs. Adenovirus-mediated expression of VEGF-a in MEFs potentiated BMP9-induced early and late osteogenic markers, including alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). In stem cell implantation assays, VEGF-a augmented BMP9-induced ectopic bone formation. VEGF-a in combination with BMP9 effectively increased the bone volume and osteogenic activity. However, the synergistic effect was efficiently abolished by the phosphoinositide 3-kinase (PI3K)/AKT inhibitor LY294002. These results demonstrated that BMP9 may crosstalk with VEGF-a through the PI3K/AKT signaling pathway to induce osteogenic differentiation in MEFs. Thus, our findings demonstrate the effects of VEGF-a on BMP9-induced bone formation and provide a new potential strategy for treating nonunion fractures, large segmental bony defects, and/or osteoporotic fractures.


2002 ◽  
Vol 39 (4) ◽  
pp. 488-493 ◽  
Author(s):  
B. Restucci ◽  
S. Papparella ◽  
P. Maiolino ◽  
G. De Vico

Vascular endothelial growth factor (VEGF) is a dimeric protein that stimulates angiogenesis in vitro and in vivo by inducing endothelial cell proliferation and migration. In this immunohistochemical study, VEGF-immunolabeled cells were counted in a series of 10 benign and 40 malignant canine mammary tumors. The morphologic pattern of VEGF positivity (intensity of immunolabeling and VEGF granule size and distribution) was also evaluated. A low number of cells weakly positive for VEGF with few and small granules polarized to the luminal pole was detected in benign neoplasms. In contrast, in malignancies a high number of VEGF-positive cells had strong immunolabeling, often with large granules found diffusely in the cytoplasm. This level of immunolabeling was more pronounced in the less differentiated, more malignant phenotypes (grade 3). Macrophages, which can synthesize VEGF, were strongly positive. Stromal and myoepithelial cells were negative. VEGF data were correlated statistically with intratumoral microvessel density (number of newly formed microvessels) and both measures were greater in less differentiated malignant neoplasms, demonstrating that angiogenesis and malignancy increase together. VEGF appears to be a powerful angiogenic factor in canine mammary tumors.


Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 253
Author(s):  
Xi Guo ◽  
Hong Yi ◽  
Tin Chiu Li ◽  
Yu Wang ◽  
Huilin Wang ◽  
...  

Vascular endothelial growth factor (VEGF) is a well-known angiogenic factor that plays a critical role in various physiological and pathological processes. VEGF also contributes to the process of embryo implantation by enhancing embryo development, improving endometrial receptivity, and facilitating the interactions between the developing embryo and the endometrium. There is a correlation between the alteration of VEGF expression and reproductive failure, including recurrent implantation failure (RIF) and recurrent miscarriage (RM). In order to clarify the role of VEGF in embryo implantation, we reviewed recent literature concerning the expression and function of VEGF in the reproductive system around the time of embryo implantation and we provide a summary of the findings reported so far. We also explored the effects and the possible underlying mechanisms of action of VEGF in embryo implantation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Iman S. Naga ◽  
Amel Abdel Fattah Kamel ◽  
Said Ahmed Ooda ◽  
Hadeer Muhammad Fath Elbab ◽  
Rania Mohamed El-Sharkawy

Abstract Background Hepatitis C virus infection is a global health challenge with Egypt being one of the highly affected countries. IL-10 has been suggested as a suitable marker to assess necroinflammation and to monitor the progression of liver damage. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor playing a central role in many physiological as well as pathological processes. Several factors can be predictive of the response to treatment and achievement of SVR; some of which are host-related, and others are virus-related. The gene expression of IL-10 and VEGF have multiple effects for treatment response. The aim of the present work was to study the effect of treatment with directly acting agents (DAA) on the expression of VEGF and IL-10 genes in chronic hepatitis C virus-infected Egyptian genotype-4a patients. Twenty-five HCV subjects where evaluated for IL-10 and VEGF gene expression before and after treatment with DAA. Results IL-10 expression was downregulated in 92% of the cases. VEGF expression was heterogeneous showing spreading of values along a wide range with 64% of the cases being downregulated. Conclusion DAAs do not completely reverse the immunological imprints established upon chronic HCV infection.


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