Co-culture System Of Endothelial Cells Research Articles

Indirect co-culture of osteoblasts and endothelial cells in vitro based on a biomimetic 3D composite hydrogel scaffold to promote the proliferation and differentiation of osteoblasts.

The field of orthopedics has long struggled with the challenge of repairing and regenerating bone defects, which involves a complex process of osteogenesis requiring coordinated interactions among different types of cells. The crucial role of endothelial cells and osteoblasts in bone vascularization and osteogenesis underscores the importance of their intimate interaction. However, efforts to bioengineer bone tissue have been impeded by the difficulty in establishing proper angiogenesis and osteogenesis in tissue structures. This study presents a novel approach to bone tissue engineering, involving a three-dimensional composite hydrogel scaffold composed of sodium alginate microspheres encapsulated in type I collagen. Using this scaffold, a three-dimensional indirect co-culture system was established for osteoblasts and endothelial cells to evaluate the osteogenic differentiation potential of osteoblasts. Results demonstrate that the non-contact co-culture system of endothelial cells and osteoblasts constructed by the composite hydrogel scaffold loaded with microspheres holds promise for bone tissue engineering. The innovative concept of an indirect co-culture system presents exciting prospects for conducting intercellular communication studies and offers a valuable in vitro tissue platform to investigate tissue regeneration.

Glucose Promotes EMMPRIN/CD147 and the Secretion of Pro-Angiogenic Factors in a Co-Culture System of Endothelial Cells and Monocytes.

Vascular complications in Type 2 diabetes mellitus (T2DM) patients increase morbidity and mortality. In T2DM, angiogenesis is impaired and can be enhanced or reduced in different tissues ("angiogenic paradox"). The present study aimed to delineate differences between macrovascular and microvascular endothelial cells that might explain this paradox. In a monoculture system of human macrovascular (EaHy926) or microvascular (HMEC-1) endothelial cell lines and a monocytic cell line (U937), high glucose concentrations (25 mmole/L) increased the secretion of the pro-angiogenic factors CD147/EMMPRIN, VEGF, and MMP-9 from both endothelial cells, but not from monocytes. Co-cultures of EaHy926/HMEC-1 with U937 enhanced EMMPRIN and MMP-9 secretion, even in low glucose concentrations (5.5 mmole/L), while in high glucose HMEC-1 co-cultures enhanced all three factors. EMMPRIN mediated these effects, as the addition of anti-EMMPRIN antibody decreased VEGF and MMP-9 secretion, and inhibited the angiogenic potential assessed through the wound assay. Thus, the minor differences between the macrovascular and microvascular endothelial cells cannot explain the angiogenic paradox. Metformin, a widely used drug for the treatment of T2DM, inhibited EMMPRIN, VEGF, and MMP-9 secretion in high glucose concentration, and the AMPK inhibitor dorsomorphin enhanced it. Thus, AMPK regulates EMMPRIN, a key factor in diabetic angiogenesis, suggesting that targeting EMMPRIN may help in the treatment of diabetic vascular complications.

CBFA2T3-GLIS2 model of pediatric acute megakaryoblastic leukemia identifies FOLR1 as a CAR T cell target.

The CBFA2T3-GLIS2 (C/G) fusion is a product of a cryptic translocation primarily seen in infants and early childhood and is associated with dismal outcome. Here, we demonstrate that the expression of the C/G oncogenic fusion protein promotes the transformation of human cord blood hematopoietic stem and progenitor cells (CB HSPCs) in an endothelial cell coculture system that recapitulates the transcriptome, morphology, and immunophenotype of C/G acute myeloid leukemia (AML) and induces highly aggressive leukemia in xenograft models. Interrogating the transcriptome of C/G-CB cells and primary C/G AML identified a library of C/G-fusion-specific genes that are potential targets for therapy. We developed chimeric antigen receptor (CAR) T cells directed against one of the targets, folate receptor α (FOLR1), and demonstrated their preclinical efficacy against C/G AML using in vitro and xenograft models. FOLR1 is also expressed in renal and pulmonary epithelium, raising concerns for toxicity that must be addressed for the clinical application of this therapy. Our findings underscore the role of the endothelial niche in promoting leukemic transformation of C/G-transduced CB HSPCs. Furthermore, this work has broad implications for studies of leukemogenesis applicable to a variety of oncogenic fusion-driven pediatric leukemias, providing a robust and tractable model system to characterize the molecular mechanisms of leukemogenesis and identify biomarkers for disease diagnosis and targets for therapy.

A mouse infection model and long-term lymphatic endothelium co-culture system to evaluate drugs against adult Brugia malayi.

The development of new drugs targeting adult-stage lymphatic filarial nematodes is hindered by the lack of a robust long-term in vitro culture model. Testing potential direct-acting and anti-Wolbachia therapeutic candidates against adult lymphatic filariae in vitro requires their propagation via chronic infection of gerbils. We evaluated Brugia malayi parasite burden data from male Mongolian gerbils compared with two immune-deficient mouse strains highly susceptible to B. malayi: CB.17 Severe-Combined Immmuno-Deficient (SCID) and interleukin-4 receptor alpha, interleukin-5 double knockout (IL-4Rα-/-IL-5-/-) mice. Adult worms generated in IL-4Rα-/-IL-5-/- mice were tested with different feeder cells (human embryonic kidney cells, human adult dermal lymphatic endothelial cells and human THP-1 monocyte differentiated macrophages) and comparative cell-free conditions to optimise and validate a long-term in vitro culture system. Cultured parasites were compared against those isolated from mice using motility scoring, metabolic viability assay (MTT), ex vivo microfilariae release assay and Wolbachia content by qPCR. A selected culture system was validated as a drug screen using reference anti-Wolbachia (doxycycline, ABBV-4083 / flubentylosin) or direct-acting compounds (flubendazole, suramin). BALB/c IL-4Rα-/-IL-5-/- or CB.17 SCID mice were superior to Mongolian gerbils in generating adult worms and supporting in vivo persistence for periods of up to 52 weeks. Adult females retrieved from BALB/c IL-4Rα-/-IL-5-/- mice could be cultured for up to 21 days in the presence of a lymphatic endothelial cell co-culture system with comparable motility, metabolic activity and Wolbachia titres to those maintained in vivo. Drug studies confirmed significant Wolbachia depletions or direct macrofilaricidal activities could be discerned when female B. malayi were cultured for 14 days. We therefore demonstrate a novel methodology to generate adult B. malayi in vivo and accurately evaluate drug efficacy ex vivo which may be adopted for drug screening with the dual benefit of reducing overall animal use and improving anti-filarial drug development.

Chemokine (C-C motif) ligand 2-enhanced adipogenesis and angiogenesis of human adipose-derived stem cell and human umbilical vein endothelial cell co-culture system in adipose tissue engineering.

Human adipose-derived stem cells (hADSCs) and human umbilical vein endothelial cells (HUVECs) co-cultured in vitro are widely used in adipose tissue engineering but exhibit various limitations. Chemokine (C-C motif) ligand 2 (CCL2) has been proved essential during adipogenesis and angiogenesis in vivo. We examined whether adipogenesis and angiogenesis could also be directly promoted by CCL2 in vitro. Cells were cultured with 0, 10, 50, and 100ng/ml CCL2. The effects of CCL2 on adipogenesis of hADSCs, and lipid accumulation in the positive control group (hADSCs), blank control group (hADSCs+HUVECs), and experimental group (hADSCs+HUVECs+CCL2) in the hADSC and HUVEC direct co-culture system were evaluated by Oil Red O staining. Angiogenesis in the presence of CCL2 was evaluated by Matrigel tube formation assay. Angiogenic- and adipogenic-associated gene and protein expression in the co-culture system were measured by Quantitative Real-time Polymerase Chain Reaction and western blotting, respectively. All concentrations of CCL2 promoted hADSC adipogenic differentiation and HUVEC tube formation (P<0.05). Following direct co-culture, the experimental group accumulated more lipid droplets than the positive control (P<0.0001), whereas the latter showed better adipogenesis than the blank control group. 50ng/ml CCL2 exhibited stronger adipogenic and angiogenic potential than other concentrations. After 72h of direct co-culture, the mRNA expression of adipogenic differentiation (peroxisome proliferators-activated receptorsγ, CCAAT/enhancer binding protein-α, Leptin, and lipoprotein lipase) and angiogenic genes (vascular endothelial growth factor-A, vascular endothelial growth factor receptor 2, matrix metalloprotein (MMP) 9, and 14) in the experimental group was much higher than in the control (P<0.05). The addition of 50ng/ml CCL2 in the system resulted in elevated phosphorylated Protein kinase B/AKT expression. In summary, CCL2 directly promoted adipogenesis of hADSCs and angiogenesis of HUVECs under both mono-culture and co-culture condition in vitro possibly by enhancing AKT phosphorylation. An optimal concentration of 50ng/ml CCL2 could improve the adipogenesis and angiogenesis of hADSC and HUVEC co-culture system.

Endothelial Cell Niche Promotes Leukemic Transformation of Human Cord Blood Stem/Progenitor Cells Expressing CBFA2T3-GLIS2 Oncogenic Fusion

The CBFA2T3-GLIS2 (CBF/GLIS) fusion is a product of a cryptic translocation exclusively seen in refractory infant AML. Lack of relevant model systems that accurately recapitulate this infant AML has limited progress. To overcome this barrier, we developed an endothelial cell (EC) co-culture system to support malignant transformation, self-renewal, and propagation of leukemia-initiating cells (LIC) in CBF/GLIS-transduced human cord blood hematopoietic stem/progenitor cells (CB HSPCs) ex vivo.Lack of recurrent cooperating mutations suggests that CBF/GLIS fusion might be sufficient for malignant transformation. To test this, we expressed the CBF/GLIS fusion or GFP control in CB HSPCs (CBF/GLIS-CB or GFP-CB) by lentiviral transduction and placed transduced cells in either EC co-culture or myeloid-promoting culture (MC). CBF/GLIS-CB cells expanded faster with prolonged lifespan in EC co-culture compared to MC (Figure 1A). Proliferation of CBF/GLIS-CB cells declined after transfer to either an EC trans-well culture or in suspension culture (Figure 1B), suggesting that direct contact as well as secreted factors are required for optimal growth of transduced cells.The CBF/GLIS fusion has been shown to confer enhanced megakaryocytic differentiation. At 6 weeks, CBF/GLIS-CB cells in EC co-culture formed significantly more megakaryocytic colonies than CBF/GLIS-CB cells grown in MC or CBF/GLIS-GFP cells grown in either condition (Figure 1C). At 12 weeks, CBF/GLIS-CB cells cultured in EC co-culture continued to produce numerous megakaryocytic colonies, demonstrating long lived self-renewal and enhance megakaryocytic differentiation of CBF/GLIS-CB cells co-cultured with ECs.To determine whether the EC niche promotes generation and propagation of LICs, we evaluated the murine engraftment of CBF/GLIS-CB cells expanded on ECs or in MC following 3, 6, 9 and 12 weeks of culture. CBF/GLIS-CB cells cultured in EC co-culture at each time point exhibited robust engraftment that progressed to frank leukemia in vivo (Figure 1D), demonstrating that EC co-culture promotes long-term maintenance of functional LICs. CBF/GLIS-CB cells grown in MC also induced leukemia from 3- and 6-week cultures but then became senescent at 9 and 12 weeks, suggesting limited preservation of the LICs.Flow cytometric analysis of CBF/GLIS-CB cells identified a malignant population that is of the RAM immunophenotype (CD56 hi, CD45 dim, and CD38 dim/-) previously reported in infants with CBF/GLIS AML in both culturing conditions. However, CBF/GLIS-CB cells in EC co-culture constituted an almost homogeneous population that expressed the RAM immunophenotype, whereas only a subset was detected in MC at week 6 (Figure 1E).To determine the fidelity of transformation to primary leukemia, we performed RNA-sequencing of CBF/GLIS-CB cells cultured with ECs or in MC. Unsurpervised clustering analysis demonstrated that the CBF/GLIS-CB cells from weeks 6 and 12 in EC co-culture clustered with primary CBF/GLIS-positive patient samples, but not CBF/GLIS-CB cells cultured in MC nor GFP controls (Figure 1F). Further transcriptome analysis revealed CBF/GLIS and HSC signature genes, previously identified to be associated with CBF/GLIS AML, were both significantly enriched in CBF/GLIS-CB cells grown in EC culture relative to MC (Figure 1G). These results suggested that the signaling pathways that are aberrantly dysregulated in primary CBF/GLIS leukemia are faithfully recapitulated in CBF/GLIS-CB cells co-cultured with ECs.Despite concerted efforts, previous attempts to model CBF/GLIS AML in murine hematopoietic cells have failed to generate overt leukemia. In this study, we demonstrate that in an EC co-culture system, the CBF/GLIS oncogenic fusion is sufficient to transform human CB HSPCs that faithfully recapitulates the morphology, transcriptome and immunophenotype of CBF/GLIS AML as well as highly aggressive leukemia in xenograft models. Furthermore, the EC co-culture system provides a tractable model system to further interrogate the mechanisms of leukemogenesis and identify biomarkers for disease diagnosis and targets for therapy in CBF/GLIS AML. [Display omitted] DisclosuresHylkema: Quest Diagnostics Inc: Current equity holder in publicly-traded company; Moderna: Current equity holder in publicly-traded company. Pardo: Hematologics, Inc.: Current Employment. Eidenschink Brodersen: Hematologics, Inc.: Current Employment, Other: equity ownership. Loken: Hematologics, Inc.: Current Employment, Other: current equity holder in a privately owned company.

Molecular and functional characterization of urine-derived podocytes from patients with Alport syndrome.

Alport syndrome (AS) is a genetic disorder involving mutations in the genes encoding collagen IV α3, α4 or α5 chains, resulting in the impairment of glomerular basement membrane. Podocytes are responsible for production and correct assembly of collagen IV isoforms; however, data on the phenotypic characteristics of human AS podocytes and their functional alterations are currently limited. The evident loss of viable podocytes into the urine of patients with active glomerular disease enables their isolation in a non‐invasive way. Here we isolated, immortalized, and subcloned podocytes from the urine of three different AS patients for molecular and functional characterization. AS podocytes expressed a typical podocyte signature and showed a collagen IV profile reflecting each patient's mutation. Furthermore, RNA‐sequencing analysis revealed 348 genes differentially expressed in AS podocytes compared with control podocytes. Gene Ontology analysis underlined the enrichment in genes involved in cell motility, adhesion, survival, and angiogenesis. In parallel, AS podocytes displayed reduced motility. Finally, a functional permeability assay, using a podocyte–glomerular endothelial cell co‐culture system, was established and AS podocyte co‐cultures showed a significantly higher permeability of albumin compared to control podocyte co‐cultures, in both static and dynamic conditions under continuous perfusion. In conclusion, our data provide a molecular characterization of immortalized AS podocytes, highlighting alterations in several biological processes related to extracellular matrix remodelling. Moreover, we have established an in vitro model to reproduce the altered podocyte permeability observed in patients with AS. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland..

Nitric oxide, a communicator between tumor cells and endothelial cells, mediates the anti-tumor effects of Marsdenia Tenacissima Extract (MTE).

Marsdenia tenacissima (Roxb.) Wight & Arn is a well-known traditional Chinese medicine for treating cancer. The anti-tumor effects of the water soluble component of M. tenacissima (MTE, M. Tenacissima Extract) have been intensely studied. However, the roles of microenvironmental cells in mediating the anti-tumor actions of MTE remain to be defined. To determine the roles of nitric oxide (NO) released by endothelial cells (ECs), an important component of tumor microenvironment, in regulating the anti-cancer effects of MTE, and to explore the underlying mechanisms. Co-culture system of ECs and A549 non-small cell lung cancer (NSCLC) cells was established for determining the interactions of ECs and lung cancer cells. Nitro-L-arginine methyl ester hydrochloride (L-NAME) was used to inhibit the production of NO. Cell viability was examined using cell counting kit 8 and 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. NO assay and Western blot were used to determine the involved signaling pathway. Primary lung microenvironmental cells (PLMCs) were cultured to examine the roles of NO released from the lung microenvironment in regulating the anti-cancer effects of MTE. A subcutaneous xenograft model was established to determine the involvement of NO in effects of MTE against NSCLCs in vivo. In the co-culture system of ECs and A549 NSCLC cells, MTE (30mg/mL) treatment reduced viability of lung cancer cells. However, when L-NAME (a nitric oxide synthase (NOS) inhibitor, 300μM) was introduced into the co-culture system, the NSCLC-inhibiting effects of MTE were significantly suppressed. By contrast, addition of L-NAME (300μM) did not affect the anti-cancer efficiency of MTE when ECs were not present. Mechanistically, MTE enhanced endothelial production of NO via stimulating PKA-endothelial nitric oxide synthase (eNOS) signaling. Elevated levels of NO inhibited proliferation and promoted apoptosis of the A549 NSCLC cells. Importantly, PKA-eNOS-NO signaling was effective in mediating the anti-cancer effects of MTE, when lung cancer cells were co-cultured with PLMCs. Finally, oral administration of MTE to the subcutaneous xenograft mice significantly suppressed tumor growth, while elevated NO productions. Plasma NO was also revealed to be negatively correlated with the tumor weight. ECs significantly contributed to anti-cancer effects of MTE by elevating production of NO, in a PKA-dependent manner. The present study revealed a novel anti-cancer mechanism of MTE through regulating the function of ECs, an important component of tumor microenvironment.

A gene-based anti-angiogenesis therapy as a novel strategy for cancer treatment

Angiogenesis-targeted therapy of cancer is considered a promising strategy for therapeutic management of cancer progression. Over the last two decades, a few anti-angiogenesis monoclonal antibodies (mAbs) blocking VEGF signaling have been developed and approved by the FDA. The most widely used anti-angiogenesis drug is bevacizumab which binds VEGFA and prevents its interaction with VEGF receptor leading to suppression of angiogenesis. Despite the remarkable success in development of angiogenesis inhibitory mAbs, their clinical application is limited by the high-cost of mAbs-based regimen which includes multiple doses of mAbs due to their short biological half-life. Antibody gene therapy is an alternative system of antibody production. In this study, we have developed a gene-based anti-VEGF mAb system which is expected to produce a high concentration of anti-VEGFA mAb upon a single administration in cancer patients. The full-length cDNA bevacizumab light and heavy chains joint with T2A sequence were cloned in pCDH lentivirus vector. The lentiviral particles expressing bevacizumab was produced in HEK-293T cells. Recombinant lentiviral particles containing bevacizumab (rLV-bev) efficiently transduced HEK-293cells and produced functional bevacizumab mAb. Bevacizumab expression in the transduced cell was assessed by qRT-PCR and western blot at both the mRNA and protein level, respectively. The functionality of the recombinant bevacizumab was confirmed using the tube formation assay in the co-culture system of endothelial cells and HT-29cells transduced with rLV-bev viral particles. Our results show that rLV-bev gene therapy can be useful for angiogenesis-targeted therapy of cancer.

Overexpressed fibulin-3 contributes to the pathogenesis of psoriasis by promoting angiogenesis.

Psoriasis is a chronic inflammatory skin disease. The earliest and most significant pathological change in psoriasis is angiogenesis. Fibulin-3 (Fib3) (also known as epidermal growth factor-containing fibulin-like extracellular matrix protein 1; EFEMP1) is a widely expressed extracellular matrix glycoprotein, which plays an important but contradictory role in regulating angiogenesis. However, the contribution of Fib3 to psoriasis remains unknown. To investigate the role of Fib3 in the pathogenesis of psoriasis. We first examined Fib3 expression in psoriasis cells and patient samples. We then investigated the relationship between Fib3 and angiogenesis by coculturing keratinocytes with vascular endothelial cells. Finally, we tested the therapeutic effect of a Fib3 antibody in a mouse model of psoriasis. Fib3 was overexpressed in the lesional skin of patients with psoriasis, and Fib3 levels positively correlated with psoriasis progression. Using a keratinocyte andendothelial cell coculture system, we found that keratinocyte-derived Fib3 upregulated vascular endothelial growth factor (VEGF) expression in endothelial cells and induced endothelial cell proliferation and migration. Topical application or subcutaneous injection of the Fib3 antibody decreased Psoriasis Area and Severity Index and VEGF expression in imiquimod-treated mice. Taken together, these results suggest that Fib3 is involved in the pathogenesis of psoriasis by promoting angiogenesis. Fib3 could serve as a potential target for treating psoriasis.

Development of a co-culture system of Endothelial cells and Neural stem cells

Development of a co-culture system of Endothelial cells and Neural stem cells

Development of a 3D co-culture system of endothelial cells and neural stem cells using the mesh culture technique

Development of a 3D co-culture system of endothelial cells and neural stem cells using the mesh culture technique

Cyclic tensile strain promotes the osteogenic differentiation of a bone marrow stromal cell and vascular endothelial cell co-culture system

Mechanical stimuli and neovascularization are closely coupled to osteogenic differentiation and new bone formation. The purpose of present study was to detect the effect of cyclic mechanical strain on a co-culture system of bone marrow stromal cells (BMSCs) and vascular endothelial cells (VECs) and to clarify the related mechanisms. Primary BMSCs and VECs were isolated from Sprague-Dawley rats and co-cultured at various ratios (1:0, 1:2, 1:4, 4:1, 2:1, 1:1, and 0:1). To determine optimized loading conditions, the cells were then subjected to various cyclic tensile strains (0%, 3%, 6% and 9%) using a Flexcell 5000 mechanical loading system. A protocol of 6% strain on the co-cultured cells at a 1:1 ratio was selected as the optimized culture conditions based on the best osteogenic effects, which included increased ALP activity, matrix mineralization and the expressions of VEGF, Runx-2 and Col-1. The VEGF-R inhibitor tivozanib was used to analyze the paracrine role of VEGF, and the osteogenesis-promoting effects of 6% tensile strain were abrogated in the co-cultured cells treated with tivozanib. These results demonstrate that cyclic tensile strain promotes osteogenic differentiation in BMSC/VEC co-culture systems, possibly via a VEC-mediated paracrine effect of VEGF on BMSCs.

REDV Peptide Conjugated Nanoparticles/pZNF580 Complexes for Actively Targeting Human Vascular Endothelial Cells.

Herein, we demonstrate that the REDV peptide modified nanoparticles (NPs) can serve as a kind of active targeting gene carrier to condensate pZNF580 for specific promotion of the proliferation of endothelial cells (ECs). First, we synthesized a series of biodegradable amphiphilic copolymers by ring-opening polymerization reaction and graft modification with REDV peptide. Second, we prepared active targeting NPs via self-assembly of the amphiphilic copolymers using nanoprecipitation technology. After condensation with negatively charged pZNF580, the REDV peptide modified NPs/pZNF580 complexes were formed finally. Due to the binding affinity toward ECs of the specific peptide, these REDV peptide modified NPs/pZNF580 complexes could be recognized and adhered specifically by ECs in the coculture system of ECs and human artery smooth muscle cells (SMCs) in vitro. After expression of ZNF580, as the key protein to promote the proliferation of ECs, the relative ZNF580 protein level increased from 15.7% to 34.8%. The specificity in actively targeting ECs of the REDV peptide conjugated NPs/pZNF580 complexes was still retained in the coculture system. These findings in the present study could facilitate the development of actively targeting gene carriers for the endothelialization of artificial blood vessels.

Bioactive silicate materials stimulate angiogenesis in fibroblast and endothelial cell co-culture system through paracrine effect

Angiogenesis is critical in tissue engineering, and bioceramic-induced angiogenesis has been reported. However, the role of other types of cells such as fibroblasts in this bioceramic-induced angiogenesis process has not been reported, and is closer to the in vivo situation of tissue regeneration. In this study, the paracrine effect of silicate bioceramic-induced angiogenesis in the presence of fibroblasts was confirmed by investigating the effects of calcium silicate (CS), one of the simplest silicate bioactive ceramics, on angiogenesis in co-cultures of human dermal fibroblasts (HDF) and human umbilical vein endothelial cells (HUVEC). Results showed that CS extracts stimulated the expression of vascular endothelial growth factor (VEGF) from co-cultured HDF and subsequently enhanced the expression of VEGF receptor 2 on co-cultured HUVEC (co-HUVEC). The endothelial nitric oxide synthase and nitric oxide production in co-HUVEC was then increased to finally initiate the proangiogenesis. During this process, the expression of vascular endothelial cadherin from co-HUVEC was up-regulated, and cadherin proteins were concentrated at the cell junctions to facilitate tube formation. Silicon ions are confirmed to play an important role during silicate bioceramic-inducing angiogenesis, and effective silicon ion concentrations (0.7–1.8μgml−1) are proposed.

Co-culture of vascular endothelial cells and smooth muscle cells by hyaluronic acid micro-pattern on titanium surface

Micro-patterning as an effective bio-modification technique is increasingly used in the development of biomaterials with superior mechanical and biological properties. However, as of now, little is known about the simultaneous regulation of endothelial cells (EC) and smooth muscle cells (SMC) by cardiovascular implants.In this study, a co-culture system of EC and SMC was built on titanium surface by the high molecular weight hyaluronic acid (HMW-HA) micro-pattern. Firstly, the micro-pattern sample with a geometry of 25μm wide HMW-HA ridges, and 25μm alkali-activated Ti grooves was prepared by microtransfer molding (μTM) for regulating SMC morphology. Secondly, hyaluronidase was used to decompose high molecular weight hyaluronic acid into low molecular weight hyaluronic acid which could promote EC adhesion. Finally, the morphology of the adherent EC was elongated by the SMC micro-pattern. The surface morphology of the patterned Ti was imaged by SEM. The existence of high molecular weight hyaluronic acid on the modified Ti surface was demonstrated by FTIR. The SMC micro-pattern and EC/SMC co-culture system were characterized by immunofluorescence microscopy. The nitric oxide release test and cell retention calculation were used to evaluate EC function on inhibiting hyperplasia and cell shedding, respectively.The results indicate that EC in EC/SMC co-culture system displayed a higher NO release and cell retention compared with EC cultured alone. It can be suggested that the EC/SMC co-culture system possessed superiority to EC cultured alone in inhibiting hyperplasia and cell shedding at least in a short time of 24h.

Effect of calcitonin gene‐related peptide on osteoblast differentiation in an osteoblast and endothelial cell co‐culture system

We have investigated the in vitro effects and regulatory mechanism of CGRP (calcitonin gene-related peptide) on the differentiation of OB (osteoblasts) in co-culture with HUVEC (human umbilical vein endothelial cells). Primary human MOB (mandibular OB) and OB-like cells (MG-63) were either cultured directly or indirectly co-cultured with HUVEC at a 1:1 ratio. Expression of OC (osteocalcin) was measured by ELISA, and expression of ALP (alkaline phosphatase) and collagen mRNA was measured by quantitative fluorescent PCR. For mineralization nodus, OB were stained with Alizarin Red-S. When co-cultured with HUVEC, expression of OC and ALP mRNA were increased in MG-63 (P<0.01), and the expression of OC, ALP and collagen mRNA were increased in MOB (P<0.01 or 0.05). When treated with CGRP, OC and ALP mRNA and mineralization nodus numbers were increased in the MG-63 co-culture system (P<0.01 or 0.05); OC, ALP and collagen mRNA, and mineralization nodus numbers were increased in the MOB co-culture system (P<0.01 or 0.05). The effect of CGRP regulation on the differentiation of OB is not only direct but also indirect, via its effect on HUVEC and stimulation of OB.

The effect of siRNA-VEGF on the growth of REC in retinal pigment epithelial cell and retinal endothelial cell co-culture system.

To investigate the effect of small interfering RNA (siRNA) targeting VEGF of retinal pigment epithelium (RPE) cells on the growth activity of human retinal vascular endothelial cells (RECs) under a co-culture system. By applying the vector (pGPU6)-based siRNA plasmid gene silence system, we specifically silenced VEGF expression of RPE cells (ARPE-19) through plasmid (pGPU6-VEGFA-siRNA) transfection. Reverse transcription polymerase chain reaction (RT-PCR) was applied for selecting the most efficient siRNA segment among three pGPU6-VEGF-siRNA groups (siRNA-1, siRNA-2 and siRNA-3). Treated RPE cells were co-cultured with RECs in a co-culture system made up of a 24-well culture plate and transwell inserts assembled inside During 7-day culture period, the growth capacity of RECs were observed and tested in the form of cell counting assay. Three groups were established in this study: RPE cells transfected with pGPU6-VEGF-siRNA and co-cultured with RECs (group A), RPE cells transfected with siRNA null vector and co-cultured with RECs (group B), and RECs cultured alone (group C). After transfection, VEGF expression of RPE cells in three pGPU6-VEGF-siRNA groups (siRNA-1, siRNA-2 and siRNA-3) evaluated by RT-PCR were 2.56 ± 0.45, 1.17 ± 0.38 and 4.39 ± 0.51, respectively (n=10). siRNA-2 was selected as the foremost segment for transfection (P<0.05, SNK-q test). During the 7-day co-culture period, an influence upon the growth of RECs was observed. Growth curve of RECs under co-culture showed a lower growth rate in group A than in group B (P<0.05, dunnett's test), but no significant difference between group A and group C was noted ( P>0.05, dunnett's test). RECs in group A proliferated much faster during the first four days post-transfection. Delivery of siRNA targeting VEGF plays an efficient role in down-regulating VEGF expression in RPE cells, therefore modulating the growth activity of RECs under a co-culture system in vitro. The application of this technique may provide novel evidence for the prevention and treatment of retinal neovascularisation diseases.

Activation State of the Vascular Niche Regulates Homeostasis of the Normal and Malignant Hematopoietic Stem Cells.

Abstract 3624Poster Board III-560Hematopoietic stem cells (HSCs) reside in supportive microenvironment in bone marrow called niche. Growing evidence indicates that interaction between niche component cells and HSCs might be critical to balance the quiescence, expansion, and differentiation of HSCs. The osteogenic niche has been shown to be primarily important for the maintenance and modulation of the size of the HSCs mass. It has also been shown that vascular niche, which is composed of sinusoidal endothelial cells, plays a critical role in maintenance of HSCs and leukemic cells. Understanding the mechanism by which vascular niche controls fate and number of HSCs may be useful not only to identify as yet undetermined factors that control self-renewal or differentiation of HSCs but also to elucidate physiologically relevant molecular targets to treat malignant counterpart of HSCs. We have established a co-culture system of endothelial cells and hematopoietic stem cells mimicking the vascular niche by using primary endothelial cells (PECs) transduced with adenovirus gene E4ORF1, and succeeded in over 500-fold expansion of repopulating long-term (LT)-HSCs. In this study, we evaluated as to how activation state of endothelial cells changes the endothelial cell potential in supporting LT-HSCs or leukemic cell expansion.Akt or/and p42/44 MAPK pathway activated endothelial cells were generated by transducing PECs with lenti viruses expressing E4ORF1, constitutive active Akt, constitutive active c-Raf, constitutive active K-ras or polyoma virus middle T antigen. Microarray and qPCR analysis showed there are clear differences between Akt-activated and MAPK-activated PECs in expression profile of genes involved in self-renewal or differentiation of HSCs such as jagged-1, CXCR4 and IGFBP-2. After 20 days of co-culture with mouse hematopoietic lineage negative (Lin-) cells, Akt-activated PECs supported over 200-fold increase of Lin- cells, whereas MAPK-activated PECs only supported less than 5-fold increase and Akt plus MAPK-activated PECs supported around 40-fold increase. On the contrary, MAPK-activated PECs supported hematopoietic lineage positive cells generation or leukemic cells expansion to the same extent as Akt-activated PECs. Conditioned medium of MAPK-activated, but not Akt-activated, PECs inhibited Lin- cell expansion on PECs without affecting lineage positive cell generation. We also confirmed Lin- cells cultured on Akt-activated PECs maintained more LT-HSCs activity than that cultured on MAPK-activated or Akt plus MAPK-activated PECs by competitive transplantation assays.These results indicate that activation of Akt signaling in vascular niche can support HSCs self-renewal, whereas activation of p42/44 MAPK signaling can induce HSCs differentiation. Stable endothelial cells and angiogenic endothelial cells might differently regulate HSCs fate after injury such as myelosuppression in bone marrow. We are now trying to define growth factors that regulate HSC self-renewal and differentiation by using this co-culture system. Disclosures:No relevant conflicts of interest to declare.

STIMULATION OF OESTROGEN RECEPTOR‐EXPRESSING ENDOTHELIAL CELLS WITH OESTROGEN REDUCES PROLIFERATION OF COCULTURED VASCULAR SMOOTH MUSCLE CELLS

1. Oestrogen reduces vascular smooth muscle cell proliferation in mouse vascular injury models. Data on the antiproliferative effect of oestrogen in cultured vascular smooth muscle cells (VSMC) are less conclusive than those obtained in whole animal studies. 2. In the present study, we investigated the hypothesis that oestrogen-induced attenuation of VSMC proliferation is facilitated by the presence of endothelial cells (EC) using a coculture system of EC and VSMC. 3. Treatment with a physiological concentration of oestrogen (17beta-estradiol (E2); 100 nmol/L) had no effect on fetal calf serum (FCS)-stimulated DNA synthesis in either A7r5 VSMC or bEnd.3 EC. However, stimulation of bEnd. 3 cells with E2 in a coculture system of bEnd.3 and A7r5 cells reduced FCS-induced DNA synthesis in A7r5 cells by approximately 45%. The nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (l-NAME; 100 micromol/L) did not reverse the oestrogen-induced attenuation of DNA synthesis. The antiproliferative effect of E2 may be mediated via either oestrogen receptor (ER) alpha, ERbeta or both because the bEnd.3 cells expressed immunoreactivity for both ER subtypes. 4. These data show that ERalpha- and ERbeta-expressing endothelial cells, which are stimulated with a physiological concentration of oestrogen, release a factor(s) that arrests the proliferation of cocultured VSMC. Oestrogen-induced attenuation of vascular smooth muscle cell proliferation is not prevented by L-NAME, suggesting that a mechanism other than endothelial NO is involved.