RANKL signaling in bone marrow mesenchymal stem cells negatively regulates osteoblastic bone formation

RANKL signaling is essential for osteoclastogenesis. Its role in osteoblastic differentiation and bone formation is unknown. Here we demonstrate that RANK is expressed at an early stage of bone marrow mesenchymal stem cells(BMSCs) during osteogenic differentiation in both mice and human and decreased rapidly. RANKL signaling inhibits osteogenesis by promoting β-catenin degradation and inhibiting its synthesis. In contrast, RANKL signaling has no significant effects on adipogenesis of BMSCs.Interestingly, conditional knockout of rank in BMSCs with Prx1-Cre mice leads to a higher bone mass and increased trabecular bone formation independent of osteoclasts. In addition, rank: Prx1-Cre mice show resistance to ovariectomy-(OVX) induced bone loss. Thus, our results reveal that RANKL signaling regulates both osteoclasts and osteoblasts by inhibition of osteogenic differentiation of BMSCs and promotion of osteoclastogenesis.

Engineering osteoblastic metastases to delineate the adaptive response of androgen-deprived prostate cancer in the bone metastatic microenvironment

While stromal interactions are essential in cancer adaptation to hormonal therapies,the effects of bone stroma and androgen deprivation on cancer progression in bone are poorly understood.Here,we tissue-engineered and validated an in vitro microtissue model of osteoblastic bone metastases,and used it to study the effects of androgen deprivation in this microenvironment.The model was established by culturing primary human osteoprogenitor cells on melt electrowritten polymer scaffolds,leading to a mineralized osteoblast-derived microtissue containing,in a 3D setting,viable osteoblastic cells,osteocytic cells,and appropriate expression of osteoblast/osteocyte-derived mRNA and proteins,and mineral content.Direct co-culture of androgen receptordependent/ independent cell lines (LNCaP,C4-2B,and PC3) led cancer cells to display functional and molecular features as observed in vivo.Co-cultured cancer cells showed increased affinity to the microtissues,as a function of their bone metastatic potential.Cocultures led to alkaline phosphatase and collagen-I upregulation and sclerostin downregulation,consistent with the clinical marker profile of osteoblastic bone metastases.LNCaP showed a significant adaptive response under androgen deprivation in the microtissues,with the notable appearance of neuroendocrine transdifferentiation features and increased expression of related markers (dopa decarboxylase,enolase 2).Androgen deprivation affected the biology of the metastatic microenvironment with stronger upregulation of androgen receptor,alkaline phosphatase,and dopa decarboxylase,as seen in the transition towards resistance.The unique microtissues engineered here represent a substantial asset to determine the involvement of the human bone microenvironment in prostate cancer progression and response to a therapeutic context in this microenvironment.

Aβ40 Promotes the Osteoblastic Differentiation of Aortic Valve Interstitial Cells through the RAGE Pathway

Amyloid beta(AB)peptide 40 enhances the activation of receptor for advanced glycation end products(RAGE)in immune-inflammatory diseases.RAGE exhibits several ffects in the setting of numerous cardiovascular events.We bypothesized that the Aβ40/RAGE pathway is involved in the osteoblastic differentiation of the valvular interstitial cell(VIC)phenotype,and RAGE knockout intervention could reduce the calcification of aortic valve interstitial cells(AVICs)by inhibiting the extracellular-regulated kinase1/2(ERK 1/2)/nuclear factor kappa-B(NF-kB)signaling pathway.To test this hypothesis,the activation of AB40/RAGE pathway in human calcific AVs was evaluated with immunohistochemical staining.Cultured calcific VIC models were used in vitro.The VICs were stimulated using Aβ40,with or without RAGE small interfering ribonucleic acid(siRNA),and ERK1/2 and NF-κB inhibitors for analysis.Our data revealed that AB40 induced the ERK 1/2/NF-κB signaling pathway and osteoblastic differentiation of AVICs via the RAGE pathway in vitro.

Specific bone region localization of osteolytic versus osteoblastic lesions in a patient-derived xenograft model of bone metastatic prostate cancer

Objective:Bone metastasis occurs in up to 90%of men with advanced prostate cancer and leads to fractures,severe pain and therapy-resistance.Bone metastases induce a spectrum of types of bone lesions which can respond differently to therapy even within individual prostate cancer patients.Thus,the special environment of the bone makes the disease more complicated and incurable.A model in which bone lesions are reproducibly induced that mirrors the complexity seen in patients would be invaluable for pre-clinical testing of novel treatments.The microstructural changes in the femurs of mice implanted with PCSD1,a new patient-derived xenograft from a surgical prostate cancer bone metastasis specimen,were determined.Methods:Quantitative micro-computed tomography(micro-CT)and histological analyses were performed to evaluate the effects of direct injection of PCSD1 cells or media alone(Control)into the right femurs of Rag2
/
gc
/
male mice.Results:Bone lesions formed only in femurs of mice injected with PCSD1 cells.Bone volume(BV)was significantly decreased at the proximal and distal ends of the femurs(p<0.01)whereas BV(p<0.05)and bone shaft diameter(p<0.01)were significantly increased along the femur shaft.Conclusion:PCSD1 cells reproducibly induced bone loss leading to osteolytic lesions at the ends of the femur,and,in contrast,induced aberrant bone formation leading to osteoblastic lesions along the femur shaft.Therefore,the interaction of PCSD1 cells with different bone region-specific microenvironments specified the type of bone lesion.Our approach can be used to determine if different bone regions support more therapy resistant tumor growth,thus,requiring novel treatments.

Ultrasound mechanotransduction on osteoblastic mineralization and mitigating bone loss

Introduction Mechanotransduction has demonstrated potentials for tissue adaptation in vivo and in vitro. It is well documented that ultrasound,as a mechanical signal,can produce a wide variety of biological effects in vitro and in vivo [1]. As an example,

Rapidly deforming gastric carcinosarcoma with osteoblastic component:An autopsy case report

Carcinosarcomas are rare,malignant,biphasic tumors simultaneously comprising carcinoma and sarcoma in a single tumor.We present an extremely rare case of gastric carcinosarcoma with an osteoblastic component that drastically changed its shape within 2 mo.A 59-year-old male patient presented to the emergency outpatient unit with a complaint of black stool.Gastrointestinal endoscopy showed an ulcerated mass in the cardia of the lesser curvature of the stomach.Biopsy specimens revealed only adenocarcinoma.Two months later,the ulcerated lesion drastically changed its shape into an exophytic tumor.Total gastrectomy was performed.In the resected specimen,the gastric tumor contained both adenocarcinoma and sarcoma components with lace-like osteoid.The patient died 7 mo after the operation,and an autopsy was performed.In the autopsy,widespread metastases were present in the liver,lung,lymph nodes and peritoneum.In this report,we describe a case of gastric carcinosarcoma and presume its tumorigenesis based on the autopsy findings.

Effect of a Bone Graft Substitute β Tricalcium Phosphate on Osteoblastic Genes mRNA Exprssion

To investigate the molecular aspects of osteoblastic interactions with β tricalcium phosphate （β-TCP） particles, human osteoblast-like MG-63 cells were cultured with β-TCP particles at a density of 6 mg/mL culture medium for 48 h. Then, the mRNA expression of selected genes were quantified by real-time polymerase chain reaction （PCR）, including the attachment-related genes （α integrin and actin）, the proliferation-related gene （c-jun）, and the osteoblastic markers genes （type I collagen, osteonectin, alkaline phosphatase, RUNX2 and osteoclain）. The results showed that β-TCP particles （the average size 809 nm） significantly promote the attachment and the proliferation of MG-63 cells, and slightly enhance the osteoblastic differentiation based on the analyses of the related genes expression. This study provided scientific evidences to better reveal the underlines of functions of β-TCP in bone repair.

Polydopamine Coating on Titanium Affects Osteoblastic Differentiation to a Greater Degree than Does Surface Roughness

Biointerface design can greatly influence cell behavior. Therefore, in this study we examined the effects of three surface characteristics, roughness, chemistry, and wettability, on osteoblastic cell differentiation. We examined osteoblastic differentiation on titanium (Ti) samples with four levels of roughness (average roughness: 148.6 ± 23.1, 42 ± 6.2, 14.3 ± 5.5, 7.2 ± 1.6 nm) with or without a nanolayer coating of polydopamine (PDA). In vitro osteogenic differentiation was evaluated by quantifying alkaline phosphatase (AP) activity of human fetal preosteoblastic (hFOB 1.19) cells. The change in surface chemistry of Ti samples as a result of PDA coating was assessed by XPS analysis and water contact angle measurement. Results demonstrated that PDA treated samples were more hydrophilic, compared to untreated samples, and this was substrate roughness independent. Moreover, with the exception of the substrate with an oriented texture of surface nanotopography (RTi-4), the presence of a PDA nanolayer increased AP activity independent of substrate roughness. Our results suggest that surface chemistry and wettability, induced by a PDA nanolayer coating, had a greater effect on osteoblastic differentiation than did surface roughness.

Regulative Actions of the Chinese Drugs for Tonifying the Kidney on Gene Expression of the Hypothalamic GnRH,Pituitary FSH,LH and Osteoblastic BGP

It is found that the drugs for nourishing yin to reduce pathogenic fire can significantly down-regulate,and the drugs for tonifying the kidney to replenish essence can up-regulate mRNA expression of the hypothalamic GnRH,pituitary FSH,LH and osteoblastic BGP,indicating that the Chinese drugs for tonifying the kidney can regulate gene expression of the hypothalamic GnRH,pituitary FSH,LH,and osteoblastic BGP,which is possibly one of the main mechanisms of the Chinese drug for tonifying the kidney,regulating ephebic development process and improving skeletal development in sexual precocity children.

Effects of Serum from a Fibrodysplasia Ossificans Progressiva Patient on Osteoblastic Cells

Introduction: Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant disorder of skeletal malformations and progressive extraskeletal ossification. Patients and Methods: In the present study, we present a case of FOP with marked progressive ossification of extraskeletal tissues. We investigated whether soluble factors in serum would affect the osteoblast phenotype by examining the effects of serum from this patient and control subjects on mouse osteoblastic MC3T3-E1 cells. Results: The clinical findings of this patient were compatible with FOP, and direct sequence analysis of genomic DNA demonstrated the presence of a heterozygous 617G> A (R206H) mutation of activin type 1 receptor (ACVR1). Serum from the FOP patient enhanced the level of alkaline phosphatase (ALP) in Western blotting, compared with serum from the control, in MC3T3-E1 cells. Moreover, serum from the FOP patient enhanced the levels of ALP, osteocalcin and bone morphogenetic protein-2 mRNA in these cells. Conclusion: We presented a case of FOP with progressive ossification in extra-skeletal tissues with ACVR1 mutation. The present data suggest that the serum from this patient includes some soluble factors, which might enhance the osteoblast differentiation and BMP-2 expression in mouse osteoblastic cells.

Osteoblastic and anti-osteoclastic activities of strontium-substituted silicocarnotite ceramics: In vitro and in vivo studies

Osteoporosis bone defect is a refractory orthopaedic disease which characterized by impaired bone quality and bone regeneration capacity.Current therapies,including antiosteoporosis drugs and artificial bone grafts,are not always satisfactory.Herein,a strontium-substituted calcium phosphate silicate bioactive ceramic(Sr-CPS)was fabricated.In the present study,the extracts of Sr-CPS were prepared for in vitro study and Sr-CPS scaffolds were used for in vivo study.The cytocompatibility,osteogenic and osteoclastogenic properties of Sr-CPS extracts were characterized in comparison to CPS.Molecular mechanisms were also evaluated by Western blot.Sr-CPS extracts were found to promote osteogenesis by upregulating Wnt/β-catenin signal pathways and inhibit osteoclastogenesis through downregulating NF-κB signal pathway.In vivo,micro-CT,histological and histomorphometric observation were conducted after 8 weeks of implantation to evaluate the bone formation using calvarial defects model in ovariectomized rats.Compared with CPS,Sr-CPS significantly promoted critical sized ovariectomy(OVX)calvarial defects healing.Among all the samples,Sr-10 showed the best performance due to a perfect match of bone formation and scaffold degradation rates.Overall,the present study demonstrated that Sr-CPS ceramic can dually modulate both bone formation and resorption,which might be a promising candidate for the reconstruction of osteoporotic bone defect.

Directing the osteoblastic and chondrocytic differentiations of mesenchymal stem cells:matrix vs.induction media

While both induction culture media and matrix have been reported to regulate the stem cell fate,little is known about which factor plays a more decisive role in directing the MSC differentiation lineage as well as the underlying mechanisms.To this aim,we seeded MSCs on HA-collagen and HA-synthetic hydrogel matrixes,which had demonstrated highly different potentials toward osteoblastic and chondrocytic differentiation lineages,respectively,and cultured them with osteogenic,chondrogenic and normal culture media,respectively.A systematic comparison has been carried out on the effects of induction media and matrix on MSC adhesion,cytoskeleton organization,proliferation,and in particular differentiation into the osteoblastic and chondrocytic lineages.The results demonstrated that the matrix selection had a much more profound effect on directing the differentiation lineage than the induction media did.The strong modulation effect on the transcription activities might be the critical factor contributing to the above observations in our study,where canonical Wnt-b-Catenin signal pathway was directly involved in the matrix-driven osteoblastic differentiation.Such findings not only provide a critical insight on natural cellular events leading to the osteoblastic and chondrocytic differentiations,but also have important implications in biomaterial design for tissue engineering applications.

Antagonizing exosomal miR-18a-5p derived from prostate cancer cells ameliorates metastasis-induced osteoblastic lesions by targeting Hist1h2bc and activating Wnt/β-catenin pathway

More than 50%of prostate cancer(PCa)patients have bone metastasis with osteo-blastic lesions.MiR-18a-5p is associated with the development and metastasis of PCa,but it remains unclear whether it is involved in osteoblastic lesions.We first found that miR-18a-5p was highly expressed in the bone microenvironment of patients with PCa bone metastases.To address how miR-18a-5p affects PCa osteoblastic lesions,antagonizing miR-18a-5p in PCa cells or pre-osteoblasts inhibited osteoblast differentiation in vitro.Moreover,injection of PCa cells with miR-18a-5p inhibition improved bone biomechanical properties and bone mineral mass in vivo.Furthermore,miR-18a-5p was transferred to osteoblasts by exosomes derived from PCa cells and targeted the Hist1h2bc gene,resulting in Ctnnb1 up-regulation in the Wnt/β-catenin signaling pathway.Translationally,antagomir-18a-5p significantly improved bone biomechanical properties and alleviated sclerotic lesions from osteoblastic me-tastases in BALB/c nude mice.These data suggest that inhibition of exosome-delivered miR-18a-5p ameliorates PCa-induced osteoblastic lesions.

In Vitro Comparative Effect of Three Novel Borate Bioglasses on the Behaviors of Osteoblastic MC3T3-E1 Cells

Most related investigations focused on the effects of borate glass on cell proliferation/biocompatibility in vitro or bone repair in vivo; however, very few researches were carried out on other cell behaviors. Three novel borate bioglasses were designed as scaffolds for bone regeneration in this wok. Comparative effects of three bioglasses on the behaviors of osteoblastic MC3T3-E1 cells were evaluated. Excellent cytocompatibility of these novel borate bioglasses were approved in this work. Meanwhile, the promotion on cell proliferation, protein secretion and migration with minor cell apoptosis were also discussed in details, which contributed to the potential clinical application as a new biomaterial for orthopedics.

Estrogenic activity of osthole and imperatorin in MCF-7 cells and their osteoblastic effects in Saos-2 cells

There is an increasing interest in phytoestrogens due to their potential medical usage in hormone replacement therapy(HRT). The present study was designed to investigate the in vitro effects of estrogen-like activities of two widespread coumarins, osthole and imperatorin, using the MCF-7 cell proliferation assay and their alkaline phosphatase(ALP) activities in osteoblasts Saos-2 cells. The two compounds were found to strongly stimulate the proliferation of MCF-7 cells. The estrogen receptor-regulated ERα, progesterone receptor(PR) and PS2 m RNA levels were increased by treatment with osthole and imperatorin. All these effects were significantly inhibited by the specific estrogen receptor antagonist ICI182, 780. Cell cycle analysis revealed that their proliferation stimulatory effect was associated with a marked increase in the number of MCF-7 cells in S phase, which was similar to that observed with estradiol. It was also observed that they significantly increased ALP activity, which was reversed by ICI182,780. These results suggested that osthole and imperatorin could stimulate osteoblastic activity by displaying estrogenic properties or through the ER pathway. In conclusion, osthole and imperatorin may represent new pharmacological tools for the treatment of osteoporosis.

Mechanical loading induced expression of bone morphogenetic protein-2, alkaline phosphatase activity, and collagen synthesis in osteoblastic MC3T3-E1 cells

Background Bone morphogenetic protein （BMP）-2, alkaline phosphatase （ALP）, and collagen type I are known to play a critical role in the process of bone remodeling. However, the relationship between mechanical strain and the expression of BMP-2, ALP, and COL-I in osteoblasts was still unknown. The purpose of this study was to investigate the effects of different magnitudes of mechanical strain on osteoblast morphology and on the expression of BMP-2, ALP, and COL-I. Methods Osteoblast-like cells were flexed at four deformation rates （0, 6%, 12%, and 18% elongation）. The expression of BMP-2 mRNA, ALP, and COL-I in osteoblast-like cells were determined by real-time quantitative reverse transcription polymerase chain reaction, respectively. The results were subjected to analysis of variance （ANOVA） using SPSS 13.0 statistical software. Results The cells changed to fusiform and grew in the direction of the applied strain after the mechanical strain was loaded. Expression level of the BMP-2, ALP, and COL-I increased magnitude-dependently with mechanical loading in the experimental groups, and the 12% elongation group had the highest expression （P 〈0.05）. Conclusion Mechanical strain can induce morphological change and a magnitude-dependent increase in the expression of BMP-2, ALP, and COL-I mRNA in osteoblast-like cells, which might influence bone remodeling in orthodontic treatment.

Enhanced integrin-mediated human osteoblastic adhesion to porous amorphous calcium phosphate/poly（L-lactic acid） composite

Background The initial osteoblastic adhesion to materials characterizes the first phase of cell-material interactions and influences all the events leading to the formation of new bone. In a previous work, we developed a novel amorphous calcium phosphate （ACP）/poly（L-lactic acid） （PLLA） material that demonstrated morphologic variations in its microstructure. The aim of this study was to investigate the initial interaction between this material and osteoblastic cells. Cellular attachment and the corresponding signal transduction pathways were investigated. Methods A porous ACP/PLLA composite and PLLA scaffold （as a control） were incubated in fetal bovine serum （FBS） containing phosphate-buffered saline （PBS）, and the protein adsorption was determined. Osteoblastic MG63 cells were seeded on the materials and cultured for 1, 4, 8, or 24 hours. Cell attachment was evaluated using the MTS method. Cell morphology was examined using scanning electron microscopy （SEM）. The expression levels of the genes encoding integrin subunits αl, α5, αv, β1, focal adhesion kinase （FAK）, and glyceraldehyde-3-phosphate dehydrogenase （GAPDH） were determined using real-time reverse transcription polymerase chain reaction （RT-PCR）. Results The ACP/PLLA material significantly increased the protein adsorption by 6.4-fold at 1 hour and 2.4-fold at 24 hours, compared with the pure PLLA scaffold. The attachment of osteoblastic cells to the ACP/PLLA was significantly higher than that on the PLLA scaffold. The SEM observation revealed a polygonal spread shape of cells on the ACP/ PLLA, with the filopodia adhered to the scaffold surface. In contrast, the cells on the PLLA scaffold exhibited a spherical or polygonal morphology. Additionally, real-time RT-PCR showed that the genes encoding the integrin subunits αl, αv, β1, and FAK were expressed at higher levels on the ACP/PLLA composite. Conclusions The ACP/PLLA composite promoted protein adsorption and osteoblastic adhesion. The enhanced cell adhesion may be mediated by the binding of integrin subunits αl, αv, and β1, and subsequently may be regulated through the FAK signal transduction pathways.

Dehydroepiandrosterone indirectly inhibits human osteoclastic resorption via activating osteoblastic viability by the MAPK pathway

Background Dehydroepiandrosterone （DHEA） is widely known for its beneficial effect on postmenopausal osteoporosis, although the underlying mechanisms remain mainly unclear. In this study, we tried to determine the activation of mitogen-activated protein kinase signal pathways during DHEA treatment and the indirect role of osteoblasts （OBs） on osteoclasts under the DHEA treatment of postmenopausal osteoporosis. Methods Primary human OBs and osteoclast-like cells were cultured and, we pretreated OBs with or without U0126 （a highly selective inhibitor of both MEK1 and MEK2）. The OBs were treated with DHEA. We then tested the effects of DHEA on human osteoblastic viability, osteoprotegerin production and the expression of phosphor-ERK1/2 （extracellular signal-regulated kinase）. In the presence or absence of OBs, the function of osteoclastic resorption upon DHEA treatment was calculated. Results DHEA promoted the human osteoblastic proliferation and inhibited the osteoblastic apoptosis within the concentration range of 108-106 mol/L （P 〈0.05, P 〈0.01, respectively）. Within the effective concentration range, the expression of phosphor-ERK1/2 and osteoprotegerin was increased by DHEA and blocked by U0126. In the presence of OBs, DHEA could significantly decrease the number and the area of bone resorption lacuna （P 〈0.05 and P 〈0.01, respectively）. Without OBs, however, the effects of DHEA on the bone resorption lacuna were almost completely abolished. Conclusions DHEA could indirectly inhibit the human osteoclastic resorption through promoting the osteoblastic viability and osteoprotegerin production, which is mediated by mitogen-activated protein kinases signal pathway involving the phosphor-ERK1/2.

Molecular basis of cranial suture biology and disease:Osteoblastic and osteoclastic perspectives

The normal growth and development of the skull is a tightly regulated process that occurs along the osteogenic interfaces of the cranial sutures.Here,the borders of the calvarial bones and neighboring tissues above and below,function as a complex.Through coordinated remodeling efforts of bone deposition and resorption,the cranial sutures maintain a state of patency from infancy through early adulthood as the skull continues to grow and accommodate the developing brain’s demands for expansion.However,when this delicate balance is disturbed,a number of pathologic conditions ensue;and if left uncorrected,may result in visual and neurocognitive impairments.A prime example includes craniosynostosis,or premature fusion of one or more cranial and/or facial suture(s).At the present time,the only therapeutic measure for craniosynostosis is surgical correction by cranial vault reconstruction.However,elegant studies performed over the past decade have identified several genes critical for the maintenance of suture patency and induction of suture fusion.Such deeper understandings of the pathogenesis and molecular mechanisms that regulate suture biology may provide necessary insights toward the development of non-surgical therapeutic alternatives for patients with cranial suture defects.In this review,we discuss the intricate cellular and molecular interplay that exists within the suture among its three major components:dura mater,osteoblastic related molecular pathways and osteoclastic related molecular pathways.

The water-soluble TF3 component from Eupolyphaga sinensis Walker promotes tibial fracture healing in rats by promoting osteoblast proliferation and angiogenesis

Objective:To determine the active components of Eupolyphaga sinensis Walker(Tu Bie Chong)and explore the mechanisms underlying its fracture-healing ability.Methods: A modified Einhorn method was used to develop a rat tibial fracture model.Progression of bone healing was assessed using radiological methods.Safranin O/fast green and CD31 immunohistochemical staining were performed to evaluate the growth of bone cells and angiogenesis at the fracture site.Methylthiazoletetrazolium blue and wound healing assays were used to analyze cell viability and migration.The Transwell assay was used to explore the invasion capacity of the cells.Tubule formation assays were used to assess the angiogenesis capacity of human vascular endothelial cells(HUVECs).qRT-PCR was used to evaluate the changes in gene transcription levels.Results: Tu Bie Chong fraction 3(TF3)significantly shortened the fracture healing time in model rats.X-ray results showed that on day 14,fracture healing in the TF3 treatment group was significantly better than that in the control group(P=.0086).Tissue staining showed that cartilage growth and the number of H-shaped blood vessels at the fracture site of the TF3 treatment group were better than those of the control group.In vitro,TF3 significantly promoted the proliferation and wound healing of MC3T3-E1s and HUVECs(all P<.01).Transwell assays showed that TF3 promoted the migration of HUVECs,but inhibited the migration of MC3T3-E1 cells.Tubule formation experiments confirmed that TF3 markedly promoted the ability of vascular endothelial cells to form microtubules.Gene expression analysis revealed that TF3 significantly promoted the expression of VEGFA,SPOCD1,NGF,and NGFR in HUVECs.In MC3T3-E1 cells,the transcript levels of RUNX2 and COL2A1 were significantly elevated following TF3 treatment.Conclusion: TF3 promotes fracture healing by promoting bone regeneration associated with the RUNX2 pathway and angiogenesis associated with the VEGFA pathway.