Endothelial Growth Factor Gene Expression Research Articles

Cell and gene therapy with reporter gene imaging in myocardial ischemia.

Reporter gene/probe systems have proved to be reliable for monitoring gene/cell therapy. We sought to evaluate whether a reporter gene/probe system, namely the human estrogen receptor ligand binding domain (hERL)/16α-18F fluoro-17β-estradiol (18F-FES), could be used for monitoring vascular endothelial growth factor (VEGF) gene expression and response to bone marrow mesenchymal stem cell (MSCs) therapy in ischemic heart disease. Reporter gene hERL and therapeutic gene VEGF165 were linked through internal ribosome entry site (IRES), and then the recombinant adenovirus vector Adenovirus 5-hERL-IRES-VEGF (Ad5-EIV) was constructed and transfected into MSCs, and named Ad5-EIV-MSCs. Rat myocardial infarction was induced by coronary arterial branch ligature, and Ad5-EIV-MSCs were transplanted by injection into the peripheral myocardium, while non-transfected MSCs transplantation used as controls. Fluorine-18-FDG micro-PET imaging was performed to confirm myocardial infarction 1 day after surgery. Fluorine-18-FES micro-PET/CT images were acquired 2 days after Ad5-EIV-MSCs transplantation. Myocardial specimens were obtained and stained with hematoxylin-eosin (H&E) staining to verify the myocardial infarction. The expression of estrogen receptor (ER) and VEGF was detected using immunohistochemistry (IHC). Rat myocardial infarction models were successfully produced and confirmed by H&E staining. Images of 18F-FDG PET showed obvious reduced or absent uptake of 18F-FDG on the infarct myocardium, while uniform and well-distribution on the normal myocardium. 18F-FES micro-PET/CT showed the tracer notable accumulated in the apical region where Ad5-EIV-MSCs were injected with an uptake value of 0.38±0.09%ID/g, which was much higher than that of surrounding normal myocardium with nearly no uptake of 18F-FES (0.10±0.03%ID/g, n=5, P<0.05). In the group of non-transfected MSCs, the apical uptake was similar to that of normal myocardium. Immunohistochemistry studies demonstrated positive expression of both ER and VEGF in the involved region accompanied by active angiogenesis. This study confirmed that hERL/18F-FES could be used as a reporter gene/probe system for monitoring gene and cell therapy in the ischemic heart disease.

Systemic Inflammation as a Driver of Brain Injury: the Astrocyte as an Emerging Player.

Severe systemic inflammation has strong effects on brain functions, promoting permanent neurocognitive dysfunction and high mortality rates. Additionally, hippocampal damage seems to be directly involved in this process and astrocytes play an important role in neuroinflammation and in the neuroimmune response. However, the contribution of the astrocytes to the pathology of acute brain dysfunction is not well understood. Recently, our group established a protocol for obtaining astrocyte cultures from mature brain to allow the characterization of these cells and their functions under pathologic conditions. The present study was designed to characterize astrocyte function after acute systemic inflammation induced by cecal ligation and perforation (CLP). Hippocampal astrocyte cultures from CLP animals presented increased levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-18, and cyclooxygenase-2 and decreased levels of IL-10. This proinflammatory profile was accompanied by an increase in Toll-like receptor (TLR)2 mRNA expression levels and no change either in TLR4 or in vascular endothelial growth factor (VEGF) gene expression. These alterations were associated with increased expressions of p21, nuclear factor kappa B (NFκB), and inducible nitric oxide synthase (iNOS) in astrocytes from CLP animals. The same parameters were also evaluated in whole hippocampal tissue, but differences in this profile were found compared to hippocampal astrocyte cultures from CLP, reflecting an interaction between other central nervous system cell types, which may mask specific astrocytic changes. These results improve our understanding of the mechanisms by which astrocytes react against systemic inflammation, and suggest these cells to be potential targets for therapeutic modulation.

Effect of calcitonin gene-related peptide on osteoporotic fracture healing in vitro

Objective To explore the effects of calcitonin gene-related peptide (CGRP) on proliferation of vascular endothelial cells (VECs) and osteogenic differentiation of bone mesenchymal stem cells (BMSCs) of osteoporotic rats in vitro, and cell/molecular mechanism of promoting osteoporotic fracture healing. Methods 10 3-month-old SD rats were employed to make osteoporosis model by taking bilateral ovariectomy. Micro-CT analysis was used to determine the success of modeling at 6 months of postoperation. BMSCs and VECs were isolated from osteoporotic rats by blood adherence method. 10-7-10-10 mol/L CGRP were added to the culture medium. CCK-8 method was used to examine the cell proliferation. Effect of CGRP on osteogenic differentiation of BMSCs: Alkaline phosphatase (ALP) activity, and reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of ALP, CollagenⅠ, BMP-2, Osteonectin and RunX2 gene. Effect of CGRP on vascularization of VECs: Vascular cell endothelial growth factor (VEGF) protein secretion and gene expression level were tested by ELISA and RT-PCR. Results BMSCs and VECs of osteoporotic rats were isolated successfully.The optical density (OD) values of CCK-8 method increased in a dose-dependent manner, for BMSCs at 7 d, the control group of OD value was 0.58±0.02, the CGRP group 10-7-10-10 mol/L was to 0.80±0.03, 0.79±0.03, 0.74±0.03, 0.69±0.03, difference was significant; for VECs, the control group of OD value was 2.20±0.01, the CGRP group 10-7-10-10 mol/L was to 4.12±0.04, 3.90±0.02, 3.56±0.04, 3.12±0.04, difference was significant. Effect of CGRP on osteogenic differentiation of BMSCs: Alkaline phosphatase (ALP) activity, and reverse transcription polymerase chain reaction (RT-PCR) were used to detect the expression of ALP, CollagenⅠ, BMP-2, Osteonectin and RunX2 gene. Effect of CGRP on vascularization of VECs: Vascular cell endothelial growth factor (VEGF) protein secretion and gene expression level were tested by ELISA and RT-PCR, difference between the control group and CGRP group were all significant. Conclusion 10-7 mol/L, 10-10 mol/L of CGRP can directly promote the proliferation of the BMSCs and VECs of osteoporotic rats, promote the osteogenic differentiation of BMSCs, improve the expression of VEGF gene and protein secretion, promote angiogenesis. Key words: Calcitonin gene-related peptide; Osteoporosis; Fractures, bone

Maternal vitamin D sufficiency and reduced placental gene expression in angiogenic biomarkers related to comorbidities of pregnancy

IntroductionMaternal circulating 25-hydroxyvitamin D [25(OH)D] has been shown to optimize production of 1,25-dihydroxyvitamin D [1,25(OH)2D] during pregnancy at approximately 100nmoles/L, which has pronounced effects on fetal health outcomes. Additionally, associations are noted between low maternal 25(OH)D concentrations and vascular pregnancy complications, such as preeclampsia. To further elucidate the effects of vitamin D activity in pregnancy, we investigated the role of maternal 25(OH)D, the nutritional indicator of vitamin D status, in relation to placental maintenance and, specifically, expression of placental gene targets related to angiogenesis and vitamin D metabolism. MethodsA focused analysis of placental mRNA expression related to angiogenesis, pregnancy maintenance, and vitamin D metabolism was conducted in placentas from 43 subjects enrolled in a randomized controlled trial supplementing 400IU or 4400IU of vitamin D3 per day during pregnancy. Placental mRNA was isolated from biopsies within one hour of delivery, followed by quantitative PCR. We classified pregnant women with circulating concentrations of <100nmoles/L as deficient and those with ≥100nmoles/L as sufficient. The value of each gene’s change in the PCR cycle threshold (ΔCT), which is a relative measure of target concentration, was compared with maternal 25(OH)D concentrations <100nmoles/L and ≥100nmoles/L based on a two-sample Wilcoxon test. ResultsSoluble FMS-like tyrosine kinase 1 (sFlt-1) and vascular endothelial growth factor (VEGF) gene expression was significantly downregulated in the maternal subgroup with circulating 25(OH)D ≥100ng/mL compared to the subgroup <100ng/mL. DiscussionHere, we report a significant association between maternal vitamin D status and the expression of sFlt-1 and VEGF at the mRNA level. Achieving maternal circulating 25(OH)D ≥100nmoles/L suggests the impact of maternal vitamin D3 supplementation on gene transcription in the placenta, thereby potentially decreasing antiangiogenic factors that may contribute to vascular pregnancy complications.

The Transcription Factor Bach1 Suppresses the Developmental Angiogenesis of Zebrafish.

Bach1 disrupts Wnt/β-catenin signaling, reduces the proliferation, migration, and tube formation activity of endothelial cells (ECs), and suppresses angiogenesis in mice with surgically induced hind-limb ischemia (HLI). However, the function of Bach1 during developmental angiogenesis in zebrafish remains unclear. Here, we found that zebrafish Bach1 was expressed ubiquitously during early embryonic development in zebrafish. Bach1b mRNA injection of Tg(fli1:gfp) fish disrupted intersegmental vessels (ISV) and dorsal longitudinal anastomotic vessels (DLAV) and suppressed endogenous Wnt/β-catenin signaling and Wnt8a stimulated vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) gene expression at early embryonic stages of zebrafish. Furthermore, chromatin immunoprecipitation experiments confirmed that Bach1 occupied the TCF/LEF-binding site of the VEGF promoter in human umbilical vein endothelial cells (HUVECs). Bach1 inhibited VEGF transcription by recruiting histone deacetylase 1 (HDAC1) to the VEGF promoter in HUVECs. Exogenous administration of VEGF or IL-8 partially rescued Bach1-driven antiangiogenic functions in HUVECs. Taken together, these observations indicate that Bach1 suppresses the developmental angiogenesis of zebrafish and that this function is associated with declines in Wnt/β-catenin signaling and VEGF and IL-8 expression.

Dietary glutamine supplementation enhances endothelial progenitor cell mobilization in streptozotocin-induced diabetic mice subjected to limb ischemia

Diabetes is a metabolic disorder with increased risk of vascular diseases. Tissue ischemia may occur with diabetic vascular complications. Bone marrow-derived endothelial progenitor cells (EPCs) constitute a reparative response to ischemic injury. This study investigated the effects of oral glutamine (GLN) supplementation on circulating EPC mobilization and expression of tissue EPC-releasing markers in diabetic mice subjected to limb ischemia. Diabetes was induced by a daily intraperitoneal injection of streptozotocin for 5 days. Diabetic mice were divided into 2 nonischemic groups and 6 ischemic groups. One of the nonischemic and 3 ischemic groups were fed the control diet, while the remaining 4 groups received diets with identical components except that part of the casein was replaced by GLN. The respective diets were fed to the mice for 3 weeks, and then the nonischemic mice were sacrificed. Unilateral hindlimb ischemia was created in the ischemic groups, and mice were sacrificed at 1, 7 or 21 days after ischemia. Their blood and ischemic muscle tissues were collected for further analyses. Results showed that plasma matrix metallopeptidase (MMP)-9 and the circulating EPC percentage increased after limb ischemia in a diabetic condition. Compared to groups without GLN, GLN supplementation up-regulated plasma stromal cell-derived factor (SDF)-1 and muscle MMP-9, SDF-1, hypoxia-inducible factor-1 and vascular endothelial growth factor gene expression. The CD31-immunoreactive intensities were also higher in the ischemic limb. These findings suggest that GLN supplementation enhanced circulating EPC mobilization that may promote endothelium repair at ischemic tissue in diabetic mice subjected to limb ischemia.

Evaluation of vascular endothelial growth factor gene and protein expression in canine metastatic mammary carcinomas.

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that could be associated with the induction of endothelial cell proliferation and metastasis. In this study, we evaluated VEGF gene and protein expression in canine mammary tumors (CMT), including metastatic carcinomas, to determine if there is an influence of this marker in the malignant processes and aggressiveness of CMT. We also compared VEGF protein levels with clinicopathological features. The VEGF gene and protein expression levels were evaluated by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry, respectively, in normal mammary gland samples, benign mammary tumors, nonmetastatic mammary carcinomas, and metastatic mammary carcinomas. High VEGF gene and protein levels were associated with malignant tumors compared with normal mammary glands (p = 0.0089 and p < 0.0001, respectively). Benign tumors showed an increased VEGF protein expression compared with normal samples (p = 0.0467). No significant differences in VEGF gene or protein levels were detected between benign and malignant tumors or between nonmetastatic and metastatic carcinomas, suggesting an absence in the correlation of VEGF with malignant processes and aggressiveness of CMT. No correlation of VEGF expression with clinical and histopathological parameters was observed, suggesting that VEGF could be important in the beginning of the mammary gland carcinogenic process and could be related to survival time.

전립선 암세포에서 delphinidin에 의한 HIF-1α와 STAT3 억제를 통한 혈관내피 성장 인자 발현 저해 효과

Delphinidin is a blue-red pigment and one of the major anthocyanins in plants. It plays an important role in anti-oxidant, anti-inflammatory, anti-mutagenic and anti-cancer properties. In this study, we investigated the inhibitory effects of delphinidin on vascular endothelial growth factor (VEGF) gene expression, an important factor involved in angiogenesis and tumor progression in human prostate cancer. Delphinidin decreased levels of epidermal growth factor (EGF)-induced VEGF mRNA expression in PC-3M cells. The expression of the EGF-induced hypoxia inducible factor- (HIF-) and signaling transducer and activator of transcription 3 (STAT3) proteins, which are the major transcription factors for VEGF, were inhibited by delphinidin. In addition, delphinidin decreases HRE-promoter reporter gene activity, suggesting that delphinidin can suppress the transcription of HIF- under EGF induction, leading to a decrease in the expression of VEGF. Delphinidin specifically suppressed the phosphorylation of Akt, p70S6K, and 4EBP1, but not the phosphorylation of EGFR. Therefore, our results suggest that delphinidin may inhibit human prostate cancer progression and angiogenesis by inhibiting HIF-, STAT3 and VEGF gene expression.

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Pigment epithelium-derived factor (PEDF) is encapsulated in poly lactic-co-glycolic acid (PLGA) polymer to prepare PLGA/PEDF emulsions for high efficient inhibitation on vascular endothelial growth factor (VEGF) gene expression. Analyses by Fourier transform infrared spectrum (FT-IR), transmission electron microscopy (TEM) and dynamic light scattering (DLS) proved the formation of the PLGA/PEDF emulsions. Furthermore, CCK-8 assay was used to detect the cytotoxicity of the PLGA/PEDF emulsions to human umbilical vein endothelial cells (HUVEC). Finally, the VEGF levels in the HUVEC cell are tested by enzyme-linked immunosorbent assay at different conditions, such as different concentrations of PLGA/PEDF emulsion, the culture time and the hypoxia treatment. The results showed that the obtained PLGA/PEDF emulsions were good agents for controlled release and inhibit effectively VEGF expression under hypoxia. Therefore, proliferation of HUVEC cells was inhibited by PLGA/PEDF emulsions, and the cell viability of HUVEC cells decreased gradually with increase of concentrations of PLGA/PEDF emulsions.

The neuroprotective effects of R-phenibut after focal cerebral ischemia

R-phenibut is a γ-aminobutyric acid (GABA)-B receptor and α2-δ subunit of the voltage-dependent calcium channel (VDCC) ligand. The aim of the present study was to test the effects of R-phenibut on the motor, sensory and tactile functions and histological outcomes in rats following transient middle cerebral artery occlusion (MCAO). In this study, MCAO was induced by filament insertion (f-MCAO) or endothelin-1 (ET1) microinjection (ET1-MCAO) in male Wistar or CD rats, respectively. R-phenibut was administrated at doses of 10 and 50mg/kg for 14 days in the f-MCAO or 7 days in the ET1-MCAO. The vibrissae-evoked forelimb-placing and limb-placing tests were used to assess sensorimotor, tactile and proprioceptive function. Quantitative reverse transcriptase-PCR was used to detect brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) gene expression in the damaged brain hemisphere. Both f-MCAO and ET1-MCAO resulted in statistically significant impairment of sensorimotor function and brain infarction. R-phenibut at a dose of 10mg/kg significantly improved histological outcome at day 7 in the ET1-MCAO. R-phenibut treatment at a dose of 50mg/kg significantly alleviated reduction of brain volume in damaged hemisphere in both f-MCAO and ET1-MCAO. In R-phenibut treated animals a trend of recovery of tactile and proprioceptive stimulation in the vibrissae-evoked forelimb-placing test was observed. After R-phenibut treatment at a dose of 50mg/kg statistically significant increase of BDNF and VEGF gene expression was found in damaged brain hemisphere. Taken together, obtained results provide evidence for the neuroprotective activity of R-phenibut in experimental models of stroke. These effects might be related to the modulatory effects of the drug on the GABA-B receptor and α2-δ subunit of VDCC.

Ethanolic extract of Salvia officinalis alter vascular endothelial growth factor gene expression and its receptors in the mouse endometrium at preimplantation

Salvia officinalis contains steroid and isoflavonoid coumestrol, daidzein, and genistein which are considered as phytoestrogens. Isoflavones are alternatives to hormone replacement treatment. No studies have been conducted on the effect of S. officinalis extraction on endometrial angiogenesis yet. The adult female mice in the test group received an ethanolic extract of the S. officinalis (100 mg/kg) once a day for 14 days then pseudopregnancy was induced. Uterine horns were removed for molecular and histological assessment in each group. Motic image software was used to assess the quantitative vascular parameters, and real-time PCR was done to determine vascular gene expression in the endometrium. Data analysis on gene expression showed a decrease in rate of vascular endothelial growth factor (VEGF) gene expression (1.559). VEGF receptor gene expression is accompanied by an increase in the rate of kinase insert domain protein receptor (KDR) gene expression (2.504) and FMS-like tyrosine kinase 1 (FLT1) gene expression (0.606). Although there was no significant difference in vascular density between control and test groups, a significant difference (p ≤ 0.05) was evident in the intravascular area between control and test groups at preimplantation time. It is concluded that S. officinalis may affect on implantation media because decidual angiogenesis has a main role in the maintenance of pregnancy at implantation time.

High vascular endothelial growth factor gene expression predicts poor outcome in patients with non-luminal A breast cancer.

Breast cancer is the most frequent type of cancer among women worldwide. Vascular endothelial growth factor (VEGF), the key modulator of angiogenesis, has been implicated in breast cancer susceptibility and aggressiveness. VEGF expression was determined in 99 breast cancer tissue samples using reverse transcription-polymerase chain reaction and the human epidermal growth factor receptor 2 (HER2) status was determined by immunohistochemistry. Subsequently, the associations of VEGF, HER2 and hormone receptor status with clinicopathological data were evaluated. High VEGF expression was found to be significantly correlated with the presence of lymphovascular invasion. In hormone receptor-positive/HER2-positive, HER2-positive and triple-negative breast cancer, high VEGF expression was correlated with the presence of axillary nodal metastasis and lower overall survival rates. Therefore, the assessment of the VEGF status along with the hormone receptor and HER2 status may help identify high-risk patients who may benefit from anti-VEGF treatment.

The Notch pathway is a critical regulator of angiogenesis in a skin model of ischemia.

The Notch pathway is definitely required for normal vascular development. Although the contribution of Notch in postnatal angiogenesis is the focus of intense investigation, the implication of Notch in reparative neovascularization in the skin remains unexplored. In this study, we investigated Notch changes using a skin model of ischemia. Thirty Sprague-Dawley rats were divided into two groups. In the surgery group (n = 24), a caudally based dorsal skin flap was raised and sutured back into its initial position. In the control group, no surgical procedure was performed. Tissue biopsies were obtained at different time intervals. Tissue specimens were assessed for Delta-like ligand 4 (DLL4) and vascular endothelial growth factor (VEGF) gene expression by real-time polymerase chain reaction (PCR). Immunohistochemical staining was used for detection of DLL4 in tissue materials. Quantitative assessment of skin flap microvasculature was made. Compared with normoperfused tissue, VEGF and DLL4 expressions increased significantly (p < 0.01). Immunohistochemical analysis revealed weak and patchy expression of DLL4 in microvascular endothelial cells of normoperfused tissues. Conversely, DLL4 expression was upregulated in capillary endothelial cells after ischemia. In conclusion, in this study we have shown that the Notch ligand DLL4 is upregulated in skin tissue after ischemia. A deeper understanding of these fundamental principles will aid in the development of new avenues for the treatment of blood vessel-related skin pathologies.

Hydrostatic pressure influences HIF-2 alpha expression in chondrocytes.

Hypoxia-inducible factor (HIF)-2α is considered to play a major role in the progression of osteoarthritis. Recently, it was reported that pressure amplitude influences HIF-2α expression in murine endothelial cells. We examined whether hydrostatic pressure is involved in expression of HIF-2α in articular chondrocytes. Chondrocytes were cultured and stimulated by inflammation or hydrostatic pressure of 0, 5, 10, or 50 MPa. After stimulation, heat shock protein (HSP) 70, HIF-2α, nuclear factor kappa B (NF-κB), matrix metalloproteinase (MMP)-13, MMP-3, and vascular endothelial growth factor (VEGF) gene expression were evaluated. The levels of all gene expression were increased by inflammatory stress. When chondrocytes were exposed to a hydrostatic pressure of 5 MPa, HIF-2α, MMP-13, and MMP-3 gene expression increased significantly although those of HSP70 and NF-κB were not significantly different from the control group. In contrast, HIF-2α gene expression did not increase under a hydrostatic pressure of 50 MPa although HSP70 and NF-κB expression increased significantly compared to control. We considered that hydrostatic pressure of 5 MPa could regulate HIF-2α independent of NF-κB, because the level of HIF-2α gene expression increased significantly without upregulation of NF-κB expression at 5 MPa. Hydrostatic pressure may influence cartilage degeneration, inducing MMP-13 and MMP-3 expression through HIF-2α.

Vascular endothelial growth factor gene polymorphism and protein expression in the pathogenesis of pterygium

Background and aimsVascular endothelial growth factor (VEGF) gene expression has been linked to cancer progression. Here we hypothesise that the polymorphism and protein expression of VEGF are correlated with the...

Androgen Receptor Promotes Sex-Independent Angiogenesis in Response to Ischemia and Is Required for Activation of Vascular Endothelial Growth Factor Receptor Signaling

Hypoandrogenemia is associated with an increased risk of ischemic diseases. Because actions of androgens are exerted through androgen receptor (AR) activation, we studied hind-limb ischemia in AR knockout mice to elucidate the role of AR in response to ischemia. Both male and female AR knockout mice exhibited impaired blood flow recovery, more cellular apoptosis, and a higher incidence of autoamputation after ischemia. In ex vivo and in vivo angiogenesis studies, AR-deficient vascular endothelial cells showed reduced angiogenic capability. In ischemic limbs of AR knockout mice, reductions in the phosphorylation of the Akt protein kinase and endothelial nitric oxide synthase were observed despite a robust increase in hypoxia-inducible factor 1α and vascular endothelial cell growth factor (VEGF) gene expression. In in vitro studies, siRNA-mediated ablation of AR in vascular endothelial cells blunted VEGF-stimulated phosphorylation of Akt and endothelial nitric oxide synthase. Immunoprecipitation experiments documented an association between AR and kinase insert domain protein receptor that promoted the recruitment of downstream signaling components. These results document a physiological role of AR in sex-independent angiogenic potency and provide evidence of novel cross-talk between the androgen/AR signaling and VEGF/kinase insert domain protein receptor signaling pathways.

Exposure to transforming growth factor-β1 after basic fibroblast growth factor promotes the fibroblastic differentiation of human periodontal ligament stem/progenitor cell lines

Basic fibroblast growth factor (bFGF) is a cytokine that promotes the regeneration of the periodontium, the specialized tissues supporting the teeth. bFGF, does not, however, induce the synthesis of smooth muscle actin alpha 2 (ACTA2), type I collagen (COL1), or COL3, which are principal molecules in periodontal ligament (PDL) tissue, a component of the periodontium. We have suggested the feasibility of using transforming growth factor-β1 (TGFβ1) to induce fibroblastic differentiation of PDL stem/progenitor cells (PDLSCs). Here, we investigated the effect of the subsequent application of TGFβ1 after bFGF (bFGF/TGFβ1) on the differentiation of PDLSCs into fibroblastic cells. We first confirmed the expression of bFGF and TGFβ1 in rat PDL tissue and primary human PDL cells. Receptors for both bFGF and TGFβ1 were expressed in the human PDLSC lines 1-11 and 1-17. Exposure to bFGF for 2 days promoted vascular endothelial growth factor gene and protein expression in both cell lines and down-regulated the expression of ACTA2, COL1, and COL3 mRNA in both cell lines and the gene fibrillin 1 (FBN1) in cell line 1-11 alone. Furthermore, bFGF stimulated cell proliferation of these cell lines and significantly increased the number of cells in phase G2/M in the cell lines. Exposure to TGFβ1 for 2 days induced gene expression of ACTA2 and COL1 in both cell lines and FBN1 in cell line 1-11 alone. BFGF/TGFβ1 treatment significantly up-regulated ACTA2, COL1, and FBN1 expression as compared with the group treated with bFGF alone or the untreated control. This method might thus be useful for accelerating the generation and regeneration of functional periodontium.

Rapamycin Inhibits ALDH Activity, Resistance to Oxidative Stress, and Metastatic Potential in Murine Osteosarcoma Cells

Osteosarcoma (OS) is the most common primary malignancy of bone. Mortality is determined by the presence of metastatic disease, but little is known regarding the biochemical events that drive metastases. Two murine OS cell lines, K7M2 and K12, are related but differ significantly in their metastatic potentials: K7M2 is highly metastatic whereas K12 displays much less metastatic potential. Using this experimental system, the mammalian target of rapamycin (mTOR) pathway has been implicated in OS metastasis. We also discovered that aldehyde dehydrogenase (ALDH, a stem cell marker) activity is higher in K7M2 cells than K12 cells. Rapamycin treatment reduces the expression and enzymatic activity of ALDH in K7M2 cells. ALDH inhibition renders these cells more susceptible to apoptotic death when exposed to oxidative stress. Furthermore, rapamycin treatment reduces bone morphogenetic protein-2 (BMP2) and vascular endothelial growth factor (VEGF) gene expression and inhibits K7M2 proliferation, migration, and invasion in vitro. Inhibition of ALDH with disulfiram correlated with decreased mTOR expression and activity. In conclusion, we provide evidence for interaction between mTOR activity, ALDH activity, and metastatic potential in murine OS cells. Our work suggests that mTOR and ALDH are therapeutic targets for the treatment and prevention of OS metastasis.

Degradable Segmented Polyurethane Elastomers for Bone Tissue Engineering: Effect of Polycaprolactone Content

Segmented polyurethanes (PURs), consisting of degradable poly(a-hydroxy ester) soft segments and aminoacid-derived chain extenders, are biocompatible elastomers with tunable mechanical and degradative properties suitable for a variety of tissue-engineering applications. In this study, a family of linear PURs synthesized from poly(ϵ-caprolactone) (PCL) diol, 1,4-diisocyanobutane and tyramine with theoretical PCL contents of 65–80 wt% were processed into porous foam scaffolds and evaluated for their ability to support osteoblastic differentiation in vitro. Differential scanning calorimetry and mechanical testing of the foams indicated increasing polymer crystallinity and compressive modulus with increasing PCL content. Next, bone marrow stromal cells (BMSCs) were seeded into PUR scaffolds, as well as poly(lactic-co-glycolic acid) (PLGA) scaffolds, and maintained under osteogenic conditions for 14 and 21 days. Analysis of cell number indicated a systematic decrease in cell density with increasing PUR stiffness at both 14 and 21 days in culture. However, at these same time points the relative mRNA expression for the bone-specific proteins osteocalcin and the growth factors bone morphogenetic protein-2 and vascular endothelial growth factor gene expression were similar among the PURs. Finally, prostaglandin E2 production, alkaline phosphatase activity and osteopontin mRNA expression were highly elevated on the most-crystalline PUR scaffold as compared to the PLGA and PUR scaffolds. These results suggest that both the modulus and crystallinity of the PUR scaffolds influence cell proliferation and the expression of osteoblastic proteins.

Angiogenesis and myogenesis in mouse tibialis anterior muscles during distraction osteogenesis: VEGF, its receptors, and myogenin genes expression

Angiogenesis and myogenesis occur in the surrounding skeletal muscles following distraction osteogenesis, but their molecular mechanisms remain unclear. The present study investigated morphological features of lengthened muscles and the time course change of vascular endothelial growth factor (VEGF), its receptors (VEGFR-1 and VEGFR-2) and myogenin gene expression profiles related to angiogenesis and myogenesis in tibialis anterior (TA) muscles with a mouse model of distraction osteogenesis, which involves 1 week of waiting period (latency phase), 2 weeks of intermittent distraction (distraction phase), and 5 weeks of remodeling period (consolidation phase). Macroscopic findings showed that lengthened TA muscles increased to approximately 42% longer and 10% heavier at the end of the process when compared to pre-surgery. During the distraction phase, VEGF and its receptors were induced in the vascular endothelial cells, myogenin-positive satellite cells and myocytes, and subsequently, capillary progression and myogenesis were increased. Real-time RT-PCR showed that Vegf, Vegfr-1, Vegfr-2, and myogenin genes expression was enhanced during the muscle lengthening. Vegf and Vegfr-1 were upregulated following the recession of angiogenesis at the consolidation phase. We conclude that upregulation of VEGF and its receptors by mechanical tension-stress could be involved in the process of angiogenesis and myogenesis in lengthened muscles.