Cell-derived Conditioned Medium Research Articles

BFGF and Activin A function to promote survival and proliferation of single iPS cells in conditioned half-exchange mTeSR1 medium.

Human induced pluripotent stem (iPS) cells can be well maintained by clonal growth. The pluripotent growth of single iPS cells is limited by low survival. To facilitate robust single iPS cells cultured in vitro, half-exchange mTeSR1 medium (HM), whole-exchange medium (WM) and iPS cell-derived conditioned medium (iPS-CM) culture were used. The effects of bFGF and Activin A on the growth of single iPS cells were explored. The dissociation and propagation of single iPS cells also included Accutase enzymatic isolation, Rho-associated protein kinase (ROCK) inhibitor Y27632 protection and high-density single-cell seeding (1×10(6) cells/well). CCK-8 assays demonstrated that the viability of clonal iPS cells in mTeSR1 medium and single iPS cells in HM, iPS-CM or WM supplemented with 100ng/ml bFGF and 10ng/ml Activin A was significantly higher than that in WM. Annexin v and propidium iodide (PI) assay, Calcein AM and EthD-III double staining also confirmed the similar results. ELISA assays showed that the levels of bFGF and Activin A of single iPS cells in HM and iPS-CM were higher than single iPS cells in WM. Meanwhile, Reverse Transcription-Polymerase Chain Reaction (RT-PCR), quantitative Polymerase Chain Reaction (qPCR), Western Blotting (WB), Immunofluorescence (IF) and karyotype analysis revealed that HM culture was able to maintain undifferentiated markers of Nanog, Klf4, Sox2, Oct4, and did not affect the karyotype of iPS cells. Undifferentiated single iPS cells in HM displayed homogenized growth. These findings demonstrate that bFGF and Activin A are important for the survival and growth of single iPS cells. HM culture system combined Accutase, Y27632 and high-density single-cell seeding can facilitate short-term growth of single iPS cells in vitro.

Improvement of radiotherapy-induced lacrimal gland injury by induced pluripotent stem cell-derived conditioned medium via MDK and inhibition of the p38/JNK pathway.

Radiation therapy is the most widely used and effective treatment for orbital tumors, but it causes dry eye due to lacrimal gland damage. Induced pluripotent stem cell-derived conditioned medium (iPSC-CM) has been shown to rescue different types of tissue damage. The present study investigated the mechanism of the potential radioprotective effect of IPS cell-derived conditioned medium (iPSC-CM) on gamma-irradiation-induced lacrimal gland injury (RILI) in experimental mice. In this study, we found that iPSC-CM ameliorated RILI. iPSC-CM markedly decreased radiotherapy induced inflammatory processes, predominantly through suppressing p38/JNK signaling. Further signaling pathway analyses indicated that iPSC-CM could suppress Akt (Protein Kinase B, PKB) phosphorylation. High levels of midkine (MDK) were also found in iPSC-CM and could be involved in lacrimal gland regeneration by promoting cell migration and proliferation. Thus, our study indicates that inhibiting the p38/JNK pathway or increasing the MDK level might be a therapeutic target for radiation-induced lacrimal gland injury.

Co-culture with mature islet cells augments the differentiation of insulin-producing cells from pluripotent stem cells.

Islet transplantation has been hampered by the shortage of islet donors available for diabetes therapy. However, pluripotent stem cells (PSCs) can be an alternative source of insulin-producing cells (IPCs) because of their capacity for self-renewal and differentiation. We described a method to efficiently differentiate PSCs into IPCs by co-culturing mature islets with directed-differentiated pancreatic endoderm (PE) cells from mouse and human PSCs. PE cells co-cultured with islet cells or islet cell-derived conditioned medium (CM) showed increased expression levels of β-cell markers; significantly higher levels of proinsulin- and Newport Green (NG)-positive cells, which revealed the characteristics of insulin producing cells; and increased insulin secretion upon glucose stimulation. Co-culturing human PE cells with islet cells was also effective to differentiate PE cells into IPCs. Diabetic nude mice transplanted with co-cultured cells exhibited restored euglycemia, human C-peptide release, and improved glucose tolerance. Immunohistochemistry revealed that insulin+/C-peptide + cells existed in the grafted tissues. These results suggest that mature islet cells can increase the differentiation efficiency of PE cells into mature IPCs via paracrine effects.

Prospect of stem cell conditioned medium in regenerative medicine.

Background. Stem cell-derived conditioned medium has a promising prospect to be produced as pharmaceuticals for regenerative medicine. Objective. To investigate various methods to obtain stem cell-derived conditioned medium (CM) to get an insight into their prospect of application in various diseases. Methods. Systematic review using keywords “stem cell” and “conditioned medium” or “secretome” and “therapy.” Data concerning treated conditions/diseases, type of cell that was cultured, medium and supplements to culture the cells, culture condition, CM processing, growth factors and other secretions that were analyzed, method of application, and outcome were noted, grouped, tabulated, and analyzed. Results. Most of CM using studies showed good results. However, the various CM, even when they were derived from the same kind of cells, were produced by different condition, that is, from different passage, culture medium, and culture condition. The growth factor yields of the various types of cells were available in some studies, and the cell number that was needed to produce CM for one application could be computed. Conclusion. Various stem cell-derived conditioned media were tested on various diseases and mostly showed good results. However, standardized methods of production and validations of their use need to be conducted.

Novel Evidence That Human Umbilical Cord Blood-Purified CD133+ cells Secrete Several Soluble Factors and Microvesicles/Exosomes That Mediate Paracrine, Pro-Angiopoietic Effects Of These Cells – Implications For and Important Role Of Paracrine Effects in stem Cell Therapies In Regenerative Medicine

BackgroundPopulations of CD34+, CD34+CXCR4+, and CD133+ cells are currently employed in the clinic to treat damaged organs (e.g., heart after myocardial infarction [AMI]). These cells are highly enriched, primarily for hematopoietic stem/progenitor cells (HSPCs), and for many years it has been wrongly supposed that HSPCs can trans-dedifferentiate into tissue-specific cells. However, even when improvement of organ function is observed after employing these cells in therapy, the lack of a convincing demonstration of significant donor-recipient chimerism in treated tissues in most of the studies performed indicates that mechanisms other than trans-dedifferentiation play a significant role in positive clinical outcomes. In support of this conclusion, we have already reported that CD34+ cells secrete a variety of growth factors, cytokines, chemokines, and bioactive lipids that interact with the surrounding microenvironment (Blood 2001;97:3075). Furthermore, microvesicles (MVs) or exosomes shed from the cell surface or derived from the intracellular membrane compartment (respectively) are important mediators in cell-to-cell communication and, as we demonstrated, may affect the biology of target cells by horizontal transfer of mRNA and proteins (Leukemia 2006;20:847). HypothesisWe hypothesized that some reported positive outcomes in adult stem cell therapies (e.g., when employing CD133+ cells) can be explained by the paracrine effects of these cells, involving both soluble factors as well as cell membrane-derived MVs. Experimental strategiesCD133+ cells were purified from UCB (>95% purity as checked by FACS) and incubated for 24 hours in RPMI at 37°C in a small volume of medium supplemented with 0.5% albumin. Subsequently, we harvested conditioned media (CM) from these cells and isolated CD133+ cell-shed microvesicles (MVs) by high-speed centrifugation. We then employed sensitive ELISA assays to measure the concentration of important pro-angiopoietic and anti-apoptotic factors in CD133+ cell-derived CM and isolated mRNA from both CD133+ cells and CD133+ cell-derived MVs for RQ-PCR analysis of gene expression. Subsequently, the chemotactic activity of CD133+ cell-derived CM and MVs was tested against human UCB endothelial cells (HUVECs), and in parallel we tested whether CD133+ cell-derived CM and MVs induce major signaling pathways in HUVECs. Finally, in in vitro functional assays, we tested the ability of CD133+ cell-derived CM and MVs to induce tube formation by HUVECs and the ability of in vivo Matrigel assay implants to induce angiogenesis. ResultsWe observed that highly purified UCB-derived CD133+ cells secrete several pro-angiopoietic factors (e.g., VEGF, KL, FGF-2, and IGF-1) into CM and shed microvesicles (MVs) from the cell surface and endosomal compartment that are enriched for mRNAs encoding VEGF, KL, FGF-2, and IGF-1. Both CD133+ cell-derived CM and MVs possessed anti-apoptotic properties, increased the in vitro cell survival of endothelial cells, stimulated phosphorylation of MAPKp42/44 and AKT in HUVECs, induced chemotactic migration, proliferation, and in vitro tube formation in HUVECs as well as stimulated in vivo angiogenesis in Matrigel implants. ConclusionsBoth in vitro and in vivo observations in animal models suggest that an important role for CD133+ cell-derived paracrine signals should be considered when evaluating clinical outcomes following the use of purified CD133+ cells in regenerative medicine. Overall, these cell-derived paracrine signals may explain the therapeutic benefits of adult stem cells employed in regeneration of, for example, heart following AMI. Finally, we will discuss several possibilities for enhancing secretion and modulating the composition of these paracrine signals, which could potentially be explored in the clinic. Disclosures:No relevant conflicts of interest to declare.

TSG (2,3,4’ ,5-tetrahydroxystilbene 2-O-β-D-glucoside) suppresses induction of pro-inflammatory factors by attenuating the binding activity of nuclear factor-κB in microglia

BackgroundInduction of pro-inflammatory factors is one of the characteristics of microglia activation and can be regulated by numerous active components of Chinese traditional herbs. Suppression of pro-inflammatory factors is beneficial to alleviate microglia-mediated cell injury. The present study aims to investigate the effect and possible mechanism of 2,3,4’,5-tetrahydroxystilbene 2-O-β-D-glucoside (TSG) on LPS-mediated induction of pro-inflammatory factors in microglia.MethodsWestern blot, ELISA, and Hoechst 33258 were used to measure the protein expression, TNF-α/IL-6 content, and apoptotic nuclei, respectively. The mRNA level was measured by real time-PCR. Nitric oxide (NO) content, lactate dehydrogenase (LDH) content, and NF-κB binding activity were assayed by commercial kits.ResultsTSG reduced iNOS protein expression as well as TNF-α, IL-6, and NO content in LPS-stimulated BV-2 cells. TSG attenuated the increase in apoptotic nuclei, caspase-3 cleavage, and LDH content induced by BV-2 cell-derived conditioned medium in primary hippocampal neurons. Mechanistic studies showed that TSG reduced the mRNA level of iNOS, TNF-α, and IL-6. TSG failed to suppress IκB-α degradation, NF-κB phosphorylation and nuclear translocation, and ERK1/2, JNK, and p38 phosphorylation. TSG, however, markedly reduced the binding of NF-κB to its DNA element. Chromatin immunoprecipitation (ChIP) assays confirmed that TSG reduced NF-κB binding to the iNOS promoter. These findings were ascertained in primary microglia where the LPS-induced increase in iNOS expression, NO content, apoptotic nuclei, and NF-κB binding to its DNA element were diminished by TSG.ConclusionsThese studies demonstrate that TSG attenuates LPS-mediated induction of pro-inflammatory factors in microglia through reducing the binding activity of NF-κB. This might help us to further understand the pharmacological role of TSG in inflammatory response in the central nervous system.

Corneal Endothelial Expansion Promoted by Human Bone Marrow Mesenchymal Stem Cell-Derived Conditioned Medium

Healthy corneal endothelium is essential for maintaining corneal clarity, as the damage of corneal endothelial cells and loss of cell count causes severe visual impairment. Corneal transplantation is currently the only therapy for severe corneal disorders. The greatly limited proliferative ability of human corneal endothelial cells (HCECs), even in vitro, has challenged researchers to establish efficient techniques for the cultivating HCECs, a pivotal issue for clinical applications. The aim of this study was to evaluate conditioned medium (CM) obtained from human bone marrow-derived mesenchymal stem cells (MSCs) (MSC-CM) for use as a consistent expansion protocol of HCECs. When HCECs were maintained in the presence of MSC-CM, cell morphology assumed a hexagonal shape similar to corneal endothelial cells in vivo, as opposed to the irregular cell shape observed in control cultures in the absence of MSC-CM. They also maintained the functional protein phenotypes; ZO-1 and Na+/K+-ATPase were localized at the intercellular adherent junctions and pump proteins of corneal endothelium were accordingly expressed. In comparison to the proliferative potential observed in the control cultures, HCECs maintained in MSC-CM were found to have more than twice as many Ki67-positive cells and a greatly increased incorporation of BrdU into DNA. MSC-CM further facilitated the cell migration of HCECs. Lastly, the mechanism of cell proliferation mediated by MSC-CM was investigated, and phosphorylation of Akt and ERK1/2 was observed in HCECs after exposure to MSC-CM. The inhibitor to PI 3-kinase maintained the level of p27Kip1 for up to 24 hours and greatly blocked the expression of cyclin D1 and D3 during the early G1 phase, leading to the reduction of cell density. These findings indicate that MSC-CM not only stimulates the proliferation of HCECs by regulating the G1 proteins of the cell cycle but also maintains the characteristic differentiated phenotypes necessary for the endothelial functions.

Abstract 1414: The role of RUNX3 and RUNX3-related chemokines in lung cancer-induced bone resorption.

Abstract Lung cancer frequently metastasizes to bone, which is associated with significant morbidity and a dismal prognosis. Runt-related transcription factor 3 (RUNX3) functions as a tumor suppressor in many cancers, and may be also important in the development of lung cancer. In this study, we found that RUNX3 knockdown increased the proliferation, migration and invasion of human lung cancer A549 cells. Interestingly, the receptor activator of nuclear factor-kappaB ligand (RANKL)/osteoprotegerin (OPG) ratio, an index of osteoclastogenic stimulation, was significantly increased in human osteoblastic hFOB1.19 cells treated with RUNX3 knockdown A549 cell-derived conditioned medium (CM) as compared to CM of RUNX3-expressing A549 cells. In the chemokine and receptor PCR array to identify RUNX3-regulated factors that mediate bone invasion of lung cancer cells, RUNX3 knockdown led to upregulation of CCL5 and downregulation of CCL19 and CXCL11 in A549 cells. CCL5 increased the proliferation, migration and invasion of A549 cells but CCL19 and CXCL11 had not a remarkable effect. CCL5 increased RANKL/OPG ratio in hFOB1.19 cells but CCL19 and CXCL11 decreased. CCL5 promoted RANKL-induced osteoclast differentiation in BMMs, while CCL19 and CXCL11 reduced. In the mouse model that RUNX3-expressing or RUNX3 knockdown A549 cells were injected subcutaneously over the calvaria, RUNX3 knockdown resulted in the increased tumor size and severe bone destruction. Additionally, in the osteolytic bone invasion model that the cells were inoculated into bone marrow of mouse tibia, bone lesions appeared more seriously in mice injected with RUNX3 knockdown A549 cells. The serum level of CCL5 was increased, while those of CCL19 and CXCL11 were decreased, in RUNX3 knockdown A549 cell-inoculated mice as compared with RUNX3-expressing A549 cell-inoculated mice. Taken together, bone invasion of lung cancer cells may be closely related with RUNX3 and RUNX3-regulated chemokines. Citation Format: Hyun-Jeong Kim, Won-Yoon Chung, Kwang-Kyun Park. The role of RUNX3 and RUNX3-related chemokines in lung cancer-induced bone resorption. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1414. doi:10.1158/1538-7445.AM2013-1414

Active Component of Danshen (Salvia miltiorrhizaBunge), Tanshinone I, Attenuates Lung Tumorigenesis via Inhibitions of VEGF, Cyclin A, and Cyclin B Expressions

Tanshinone I (T1) and tanshinone II (T2) are the major diterpenes isolated from Danshen (Salvia miltiorrhiza Bunge). Three human lung adenocarcinoma cell lines, A549, CL1-0, and CL1-5, were treated with T1 and T2 for the in vitro antitumor test. Results showed that T1 was more effective than T2 in inhibiting the growth of lung cancer cells via suppressing the expression of VEGF, Cyclin A, and Cyclin B proteins in a dose-dependent manner. Moreover, a transgenic mice model of the human vascular endothelial growth factor-A165 (hVEGF-A 165) gene-induced pulmonary tumor was further treated with T1 for the in vivo lung cancer therapy test. T1 significantly attenuated hVEGF-A165 overexpression to normal levels of the transgenic mice (Tg) that were pretreated with human monocytic leukemia THP-1 cell-derived conditioned medium (CM). It also suppressed the formation of lung adenocarcinoma tumors (16.7%) compared with two placebo groups (50% for Tg/Placebo and 83.3% for Tg/CM/Placebo; P < 0.01). This antitumor effect is likely to slow the progression of cells through the S and G2/M phases of the cell cycle. Blocking of the tumor-activated cell cycle pathway may be a critical mechanism for the observed antitumorigenic effects of T1 treatment on vasculogenesis and angiogenesis.

Novel Evidence for the Presence of Potent, Paracrine, Pro-Angiopoietic Effects of Purified Human Umbilical Cord Blood-Derived CD133+ Cells - Implications for Adult Stem Cell Therapies in Regenerative Medicine

Abstract 4740 Background.As populations of CD34+, CD34+CXCR4+, or CD133+ cells that are enriched in stem cells, adult stem and progenitor cells purified from bone marrow (BM), mobilized peripheral blood (mPB), and umbilical cord blood (UCB) are currently employed in the clinic to treat damaged organs (e.g., heart after myocardial infarction [AMI] or injured spinal cord or liver). The cell populations expressing these phenotypes are highly enriched primarily for hematopoietic stem/progenitor cells (HSPCs) and small numbers of endothelial progenitors, and for many years it has been wrongly supposed that they can trans-dedifferentiate into tissue-specific cells. However, even when improvement of organ function is observed after employing them in therapy, the lack of a convincing demonstration for the presence of donor-recipient chimerism in treated tissues in most of the studies performed so far indicates that mechanisms other than trans-dedifferentiation of the HSPCs delivered to the damaged organs into tissue-specific cells play a significant role in some positive clinical outcomes. In support of this conclusion, evidence has accumulated that stem cells secrete a variety of growth factors, cytokines, chemokines, and bioactive lipids that interact with the surrounding microenvironment and, when used in therapy, improve cell viability in damaged organs. In particular, more attention is currently being paid to microvesicles (MVs), which are shed from the cell surface or derived from the intracellular membrane compartment as mediators in cell-to-cell communication. Hypothesis.We hypothesized that these positive outcomes in adult stem cell therapies (e.g., by employing CD133+ cells) can be explained by the paracrine effects of these cells, involving both soluble factors as well as cell membrane-derived MVs. Experimental strategies.CD133+ cells were purified from UCB by employing immunomagnetic beads (> 95% purity as checked by FACS) and incubated for 24 hours in RPMI at 37°C in a small volume of medium supplemented with 0.5% albumin. Subsequently, we harvested conditioned media (CM) from these cells and isolated CD133+ cell-shed microvesicles (MVs) by high speed centrifugation. We employed sensitive ELISA assays to measure the concentration of important pro-angiopoietic and anti-apoptotic factors in CD133+ cell-derived CM and isolated mRNA from both CD133+ cells and CD133+ cell-derived MVs for RQ-PCR analysis of gene expression. Subsequently, the chemotactic activity of CD133+ cell-derived CM and MVs was tested against human umbilical cord blood endothelial cells (HUVECs), and, in parallel, we tested whether CD133+ cell-derived CM and MVs induce major signaling pathways in HUVECs. Finally, in in vitro functional assays, we tested the ability of CD133+ cell-derived CM and MVs to induce tube formation by HUVECs and the ability of in vivo Matrigel assay implants to induce angiogenesis. Results.We observed that highly purified UCB-derived CD133+ cells express mRNAs and secrete proteins for several pro-angiopoietic factors (e.g. VEGF, KL, FGF-2, and IGF-1) into CM and shed microvesicles (MVs) from the cell surface and endosomal compartment that are enriched for mRNAs encoding VEGF, KL, FGF-2, and IGF-1. Both CD133+ cell-derived CM and MVs possessed anti-apoptotic properties, increased the in vitro cell survival of endothelial cells, stimulated phosphorylation of MAPKp42/44 and AKT in HUVECs, induced chemotactic migration, proliferation and tube formation in vitro in HUVECs, as well as stimulated in vivo angiogenesis in Matrigel implants. Conclusions.These observations suggesting an important role for CD133+ cell-derived paracrine signals should be considered when evaluating clinical outcomes using purified CD133+ cells in regenerative medicine. Overall, these cell-derived paracrine signals may explain the therapeutic benefits of adult stem cells employed in regeneration of, for example, heart AMI. Finally, we will discuss several possibilities for enhancing secretion and modulating the composition of these paracrine signals that could be explored in the clinic. Disclosures:No relevant conflicts of interest to declare.

Paracrine Proangiopoietic Effects of Human Umbilical Cord Blood-Derived Purified CD133+Cells—Implications for Stem Cell Therapies in Regenerative Medicine

CD133+ cells purified from hematopoietic tissues are enriched mostly for hematopoietic stem/progenitor cells, but also contain some endothelial progenitor cells and very small embryonic-like stem cells. CD133+ cells, which are akin to CD34+ cells, are a potential source of stem cells in regenerative medicine. However, the lack of convincing donor-derived chimerism in the damaged organs of patients treated with these cells suggests that the improvement in function involves mechanisms other than a direct contribution to the damaged tissues. We hypothesized that CD133+ cells secrete several paracrine factors that play a major role in the positive effects observed after treatment and tested supernatants derived from these cells for the presence of such factors. We observed that CD133+ cells and CD133+ cell-derived microvesicles (MVs) express mRNAs for several antiapoptotic and proangiopoietic factors, including kit ligand, insulin growth factor-1, vascular endothelial growth factor, basic fibroblast growth factor, and interleukin-8. These factors were also detected in a CD133+ cell-derived conditioned medium (CM). More important, the CD133+ cell-derived CM and MVs chemoattracted endothelial cells and display proangiopoietic activity both in vitro and in vivo assays. This observation should be taken into consideration when evaluating clinical outcomes from purified CD133+ cell therapies in regenerative medicine.

Improvement of ventilator-induced lung injury by IPS cell-derived conditioned medium via inhibition of PI3K/Akt pathway and IP-10-dependent paracrine regulation

Mechanical ventilation in patients may increase the risk of an acute lung injury (ALI), termed ventilator-induced lung injury (VILI). Induced pluripotent stem cells (iPSCs) have previously been shown to improve tissue repair in different disease models, including ALI. However, the therapeutic efficacy of iPSCs-derived conditioned medium (iPSC-CM) on ALI or VILI remains unknown. Here, we demonstrated that both iPSCs and iPSC-CM effectively decrease high-tidal-volume-induced VILI-related inflammatory processes and HMGB1 and PAI-1 production, predominantly through suppressing PI3K/Akt signaling. Notably, iPSC-CM suppressed production of macrophage inflammatory protein-2, malondialdehyde, and increased total glutathione content. Transmission electron microscopy revealed that iPSC-CM potentially restored the bronchial microstructure. This iPSC-CM efficacy could be mimicked by PI3K inhibitor LY294002 or Akt heterozygous knockout, and either treatment showed no further improvement on VILI in iPSC-CM recipients. Furthermore, iPSC-CM increased interferon gamma-induced protein 10 (IP-10) production in injured lungs. Administration of IP-10-neutralizing antibodies increased neutrophil infiltration, impaired lung oxygenation and deteriorated the protective effects mediated by iPSC-CM. Our data provide a preclinical indication regarding the therapeutic potential of iPSC-CM in VILI and suggest that inhibiting PI3K/Akt pathway or increasing IP-10 is a prospective diagnostic and therapeutic target for VILI patients.

MicroRNA-214 inhibits angiogenesis by targeting Quaking and reducing angiogenic growth factor release

Angiogenesis is a critical component of many pathological conditions in adult tissues and is essential for embryonic development. MicroRNAs are indispensable for normal vascular development, but their exact role in regulating angiogenesis remains unresolved. Previously, we have observed that miR-214 is differentially expressed in compensatory arteriogenesis. Here, we investigated the potential role of miR-214 in the process of angiogenesis. miR-214 is expressed in all major vascular cell types, and modulation of miR-214 levels in endothelial cells significantly affected tubular sprouting. In vivo silencing of miR-214 enhanced the formation of a perfused vascular network in implanted Matrigel plugs and retinal developmental angiogenesis in mice. miR-214 directly targets Quaking, a protein critical for vascular development. Quaking knockdown reduced pro-angiogenic growth factor expression and inhibited endothelial cell sprouting similar to miR-214 overexpression. In accordance, silencing of miR-214 increased the secretion of pro-angiogenic growth factors, including vascular endothelial growth factor, and enhanced the pro-angiogenic action of the endothelial cell-derived conditioned medium, whereas miR-214 overexpression had the opposite effect. Here, we report a novel role for miR-214 in regulating angiogenesis and identify Quaking as a direct target of miR-214. The anti-angiogenic effect of miR-214 is mediated through the down-regulation of Quaking and pro-angiogenic growth factor expression. This study presents miR-214 as a potential important target for pro- or anti-angiogenic therapies.

Mesenchymal stem cell-conditioned medium facilitates angiogenesis and fracture healing in diabetic rats

The most critical factor for fracture union is the blood supply to the fracture site, which is usually impaired in patients with diabetes. Recently, mesenchymal stem cells-derived conditioned medium (MSC-CM) has shown significantly higher levels of angiogenic factors, such as VEGF and IL-6. We demonstrate in this report that MSC-CM delivered in gelatin sponges stimulates angiogenesis and promotes fracture healing in a diabetic rat model. Subcutaneous implantation of gelatin sponges soaked in MSC-CM demonstrated better tissue ingrowth and higher capillary densities at 2 and 3 weeks than gelatin sponges in minimal essential medium (MEM) or 293 cell-derived conditioned medium (293-CM). Implantation of fibular defects with gelatin sponges soaked in MSC-CM enhanced bone ingrowth and fracture healing rates compared to 293-CM and MEM groups at 8 weeks. Micro-computed tomography analysis further indicated a higher new bone volume in the MSC-CM group compared to the other diabetic groups. Histological analysis with CD31 immunostaining also revealed that MSC-CM increased endothelial cell counts compared to the other groups. Together, these results indicated that gelatin sponges used to deliver MSC-CM promote angiogenesis and fracture healing in a diabetic model and may be an alternative strategy for treating fracture non-union in patients with diabetes.

Effect of Human Endometrial Stromal Cell-derived Conditioned Medium on Uterine Natural Killer (uNK) Cells’ Proliferation and Cytotoxicity

Human endometrial stromal cells are involved in the regulation of immune cell proliferation, apoptosis, differentiation, and function. In the endometrium, uNK cells are in close contact with stromal cells. The aim of the study was to investigate the effects of human endometrial stromal cells on uNK-cell proliferation and uNK-cell cytotoxicity. The conditioned medium was derived from the endometrial stromal cells in the proliferative phase, secretory phase, and early pregnancy. The effects of stromal cell-derived conditioned medium on uNK-cell proliferation and cytotoxicity were detected by mitochondrial lactate dehydrogenase-based MTS staining and flow cytometry. The stromal cell-derived conditioned medium in both secretory phase and early pregnancy significantly promoted uNK-cell proliferation. Compared with the control group, the uNK-cell cytotoxicity were significantly reduced by conditioned medium in the proliferative, secretory, and decidua groups, but there were no significant differences among these different physiological stages in the inhibiting ability. Human endometrial stromal cells may be involved in the regulation of uNK-cell functions through influencing proliferation and cytolytic activity.

Decidual NK cell-derived conditioned medium enhances capillary tube and network organization in an extravillous cytotrophoblast cell line

Extravillous cytotrophoblast (EVT) migration, invasion and endovascular differentiation are regulated by a variety of growth factors, cytokines and adhesion molecules. Decidual natural killer cells (dNK) and their secreted cytokines probably modulate these processes. In this study, we used dNK-derived conditioned medium (dNK-CM) to investigate whether or not (i) dNK-CM was able to enhance capillary tube and network formation of an EVT cell line, HTR8/SVneo, on Matrigel, (ii) PI3K/AKT pathway and p38 MAPK pathway activation were involved, and (iii) HTR8/SVneo surface ICAM-1 played a role in the process of HTR8/SVneo endovascular differentiation. The results demonstrated that HTR8/SVneo constitutively form ‘vascular’ tubes and networks after culture on Matrigel. dNK-CM enhanced and maintained tube and network formation, acquiring an endothelium-like angiogenic morphology followed by increased VEGF-C production. HTR8/SVneo cell expression level of VE-cadherin, PECAM-1, VCAM-1 and αvβ3 was unaltered by dNK-CM, whereas ICAM-1 expression level was increased. Anti-human ICAM-1 blocking antibody inhibited HTR8/SVneo migration and partially reversed dNK-CM-mediated enhancement of HTR8/SVneo tube and network formation. PI3K/AKT and p38 MAPK pathways were activated in dNK-CM-mediated enhancement of HTR8/SVneo tube and network formation. The PI3K/AKT and p38 MAPK pathway inhibitors (LY294002 and SB202190, respectively) decreased dNK-CM-stimulated ICAM-1 induction, HTR8/SVneo migration, and reversed tube and network formation. The results suggest that dNK cell-secreted growth factors and cytokines participate in the regulation of HTR8/SVneo endothelium-like tube formation. Adhesion molecules, particularly ICAM-1, expressed on EVT may participate in the process. To our knowledge, this is the first report of a role for ICAM-1 in EVT angiogenesis, as previously reported for endothelial cells.

Enrichment and Clonal Culture of Progenitor Cells During Mouse Postnatal Liver Development in Mice

Stem and progenitor cells exist in normal postnatal livers. However, it has not been possible to clonally isolate or analyze postnatal liver stem/progenitor-like cells (PLSCs) derived from noninjured livers because of a lack of specific surface markers. This study aimed to establish a primary culture system for clone-sorted PLSCs. To investigate proliferation and differentiation of PLSCs, subpopulations of nonparenchymal cells derived from noninjured livers were purified and cultured using a single-cell culture system. Cells were grown in fetal liver cell-derived conditioned medium in the presence of the Rho-associated kinase (ROCK) inhibitor Y-27632. We identified CD13 and CD133 as markers expressed on the PLSC-containing population in noninjured livers and established an efficient single-cell culture system to clonally analyze PLSCs. Culture of PLSCs is difficult, even using conditioned medium, but the addition of Y-27632 increased PLSC cell proliferation. The proportion of progenitor cells among nonparenchymal cells decreased during postnatal liver development; however, a PLSC population was still preserved in 3-month-old mice. Long-term cultivated cells derived from clone-sorted cells in normal livers were established and were called normal-liver-derived stem-like cells (NLS cells). NLS cells could differentiate into hepatocyte-like and cholangiocyte-like cells under appropriate culture conditions and underwent self-renewal-like activity in serial reclone-sorted culture. CD13 and CD133 were expressed on progenitor cells derived from fetal and postnatal liver, whereas CD49f (integrin alpha6 subunit) was strongly expressed only on PLSCs. These results demonstrate the presence of progenitor cells in the CD13(+)CD49f(+)CD133(+) subpopulation of nonhematopoietic cells derived from noninjured postnatal livers.

Extrinsic factors derived from mouse embryonal carcinoma cell lines maintain pluripotency of mouse embryonic stem cells through a novel signal pathway

Embryonic carcinoma (EC) cells, which are malignant stem cells of teratocarcinoma, have numerous morphological and biochemical properties in common with pluripotent stem cells such as embryonic stem (ES) cells. However, three EC cell lines (F9, P19 and PCC3) show different developmental potential and self-renewal capacity from those of ES cells. All three EC cell lines maintain self-renewal capacity in serum containing medium without Leukemia Inhibitory factor (LIF) or feeder layer, and show limited differentiation capacity into restricted lineage and cell types. To reveal the underlying mechanism of these characteristics, we took the approach of characterizing extrinsic factors derived from EC cells on the self-renewal capacity and pluripotency of mouse ES cells. Here we demonstrate that EC cell lines F9 and P19 produce factor(s) maintaining the undifferentiated state of mouse ES cells via an unidentified signal pathway, while P19 and PCC3 cells produce self-renewal factors of ES cells other than LIF that were able to activate the STAT3 signal; however, inhibition of STAT3 activation with Janus kinase inhibitor shows only partial impairment on the maintenance of the undifferentiated state of ES cells. Thus, these factors present in EC cells-derived conditioned medium may be responsible for the self-renewal capacity of EC and ES cells independently of LIF signaling.

Abstract 1845: Adult Cardiac Progenitor Cells Promote Angiogenesis and Cardioprotection through Their Secreted Soluble Vcam-1

Although cardiac progenitor cells have been thought to be the promising source of cell therapy, the precise mechanisms of their paracrine action have not been fully elucidated. Since we observed that the transplantation of clonal expanded Sca-1 positive cardiac progenitor cells (cSca-1 cells) derived from adult murine heart by using cell sheet technique improved cardiac function of infarcted heart compared to adipose tissue derived mesenchymal cells (ATMC), we explored the secreted factors highly expressed in cSca-1 cells and identified that soluble VCAM-1 (sVCAM-1) was much abundant in cSca-1 cells compared to ATMC by using cytokine antibody array. cSca-1 cells-derived conditioned medium (CM) significantly enhanced endothelial migration and matrigel tube formation and these effects were abolished by knock down of VCAM-1 (Fold increase: control, 1.0; CM, 2.97 ± 0.21; siVCAM-1, 1.98 ± 0.09; siControl, 2.76 ± 0.05, p&lt;0.01), suggesting that cSca-1 cells promote angiogenesis via their secreted sVCAM-1. We next examined whether sVCAM-1 conferred direct protective effects on cardiomyocytes. We exposed cardiomyocytes to 0.2 mM H 2 O 2 in the absence or presence of sVCAM-1 or CM and examined cardiomyocyte viability by MTT assay. The exposure of cardiomyocytes to H 2 O 2 significantly induced the cell injury. Interestingly when pretreated with sVCAM-1 or CM, the cell damages of cardiomyocytes by H 2 O 2 were significantly reduced. However when pretreated with anti-VLA4 antibody, a principal coreceptor of sVCAM-1, CM mediated cell protected effect was completely inhibited (Fold increase: control, 1.0; anti-VLA4, 0.89 ± 0.33; sVCAM-1, 1.69 ± 0.27; CM, 2.08 ± 0.28; CM+anti-VLA4, 1.07 ± 0.07, p&lt;0.01), suggesting that a crucial role of the VLA4 in inducing survival of cardiomyocytes by CM. sVCAM-1 and CM induced phosphorylation of FAK, Akt, Erk and p38 MAPK in neonatal rat cardiomyocytes. When pretreated with wortmannin, SB203580 and PD98059, the cardioprotective effects of sVCAM-1 and CM significantly inhibited, suggesting that sVCAM-1 might protect cardiomyocytes from oxidative stress via integrated upregulation of Akt, Erk and p38MAPK. These findings suggest cardiac progenitor cells promote angiogenesis and cardioprotection through their secreted sVCAM-1.

Ischemic brain cell-derived conditioned medium protects astrocytes against ischemia through GDNF/ERK/NF-kB signaling pathway

Conditioned medium (CM) collected from cultures of ischemic microglia, astrocytes, and neurons were protective to astrocytes under the in vitro ischemic condition (deprivation of oxygen, glucose and serum). Molecular and signaling pathway(s) responsible for the CMs protective activity were investigated. Results showed that CMs from the ischemic microglia (MCM), astrocytes (ACM) and neurons (NCM) contained glial cell line-derived neurotrophic factor (GDNF), which protects astrocytes against the in vitro ischemia. Expression of extra cellular signal-regulated kinase (ERK1/2) and nuclear factor-kappa B (NF-kB) by GDNF led to the inhibition of apoptosis of the ischemic astrocytes in a caspase 3-independent manner. However, CMs- and GDNF-mediated protection of the ischemic astrocytes was protein kinase B (Akt) independent. These results provided mechanistic data regarding how GDNF- and CMs-mediated protection of the ischemic astrocytes is taking place. These observations provide information for the use of GDNF and GDNF containing CMs in the control of cerebral ischemia.