Conditioned medium from adipose tissue-derived mesenchymal stem cells induces CD4+FOXP3+ cells and increases IL-10 secretion. J Biomed Biotechnol. 2012;2012:295167. [PMID: 23251077 PMCID: PMC3521492 DOI: 10.1155/2012/295167]

Interactions between MSCs and immune cells: implications for bone healing

It is estimated that, of the 7.9 million fractures sustained in the United States each year, 5% to 20% result in delayed or impaired healing requiring therapeutic intervention. Following fracture injury, there is an initial inflammatory response that plays a crucial role in bone healing; however, prolonged inflammation is inhibitory for fracture repair. The precise spatial and temporal impact of immune cells and their cytokines on fracture healing remains obscure. Some cytokines are reported to be proosteogenic while others inhibit bone healing. Cell-based therapy utilizing mesenchymal stromal cells (MSCs) is an attractive option for augmenting the fracture repair process. Osteoprogenitor MSCs not only differentiate into bone, but they also exert modulatory effects on immune cells via a variety of mechanisms. In this paper, we review the current literature on both in vitro and in vivo studies on the role of the immune system in fracture repair, the use of MSCs in the enhancement of fracture healing, and interactions between MSCs and immune cells. Insight into this paradigm can provide valuable clues in identifying cellular and noncellular targets that can potentially be modulated to enhance both natural bone healing and bone repair augmented by the exogenous addition of MSCs.

Interleukin 6 mediates the therapeutic effects of adipose-derived stromal/stem cells in lipopolysaccharide-induced acute lung injury

Adipose-derived stromal/stem cells (ASCs) have anti-inflammatory as well as immunosuppressive activities and are currently the focus of clinical trials for a number of inflammatory diseases. Acute lung injury (ALI) is an inflammatory condition of the lung for which standard treatment is mainly supportive due to lack of effective therapies. Our recent studies have demonstrated the ability of both human ASCs (hASCs) and mouse ASCs (mASCs) to attenuate lung damage and inflammation in a rodent model of lipopolysaccharide-induced ALI, suggesting that ASCs may also be beneficial in treating ALI. To better understand how ASCs may act in ALI and to elucidate the mechanism(s) involved in ASC modulation of lung inflammation, gene expression analysis was performed in ASC-treated (hASCs or mASCs) and control sham-treated lungs. The results revealed a dramatic difference between the expression of anti-inflammatory molecules by hASCs and mASCs. These data show that the beneficial effects of hASCs and mASCs in ALI may result from the production of different paracrine factors. Interleukin 6 (IL-6) expression in the mASC-treated lungs was significantly elevated as compared to sham-treated controls 20 hours after delivery of the cells by oropharyngeal aspiration. Knockdown of IL-6 expression in mASCs by RNA interference abrogated most of their therapeutic effects, suggesting that the anti-inflammatory properties of mASCs in ALI are explained, at least in part, by activation of IL-6 secretion.

Secretion of immunoregulatory cytokines by mesenchymal stem cells

According to the minimal criteria of the International Society of Cellular Therapy, mesenchymal stem cells (MSCs) are a population of undifferentiated cells defined by their ability to adhere to plastic surfaces when cultured under standard conditions, express a certain panel of phenotypic markers and can differentiate into osteogenic, chondrogenic and adipogenic lineages when cultured in specific inducing media. In parallel with their major role as undifferentiated cell reserves, MSCs have immunomodulatory functions which are exerted by direct cell-to-cell contacts, secretion of cytokines and/or by a combination of both mechanisms. There are no convincing data about a principal difference in the profile of cytokines secreted by MSCs isolated from different tissue sources, although some papers report some quantitative but not qualitative differences in cytokine secretion. The present review focuses on the basic cytokines secreted by MSCs as described in the literature by which the MSCs exert immunodulatory effects. It should be pointed out that MSCs themselves are objects of cytokine regulation. Hypothetical mechanisms by which the MSCs exert their immunoregulatory effects are also discussed in this review. These mechanisms may either influence the target immune cells directly or indirectly by affecting the activities of predominantly dendritic cells. Chemokines are also discussed as participants in this process by recruiting cells of the immune systems and thus making them targets of immunosuppression. This review aims to present and discuss the published data and the personal experience of the authors regarding cytokines secreted by MSCs and their effects on the cells of the immune system.

Conditioned medium from mesenchymal stem cells enhances the migration of hepatoma cells through CXCR4 up-regulation and F-actin remodeling

Interactions between tumors and mesenchymal stem cells (MSCs) can regulate cancer cell behavior and cancer progression. Rat bone marrow-derived MSCs (rMSCs) were isolated and purified by Percoll density gradient centrifugation. Conditioned media from rMSCs (MSC-CM) was prepared, and its role in cancer cell migration and the underlying molecular mechanism were investigated. MSC-CM increased the migration and up-regulated the expression of CXC chemokine receptor 4 (CXCR4) in rat hepatoma cells (CBRH-7919). F-actin remodeling was observed, and the Young's modulus was decreased in CBRH-7919 cells. A CXCR4 inhibitor suppressed the MSC-CM-induced CXCR4 expression and migration, restored the decrease in the Young's modulus and disrupted the formation of F-actin. MSC-CM thus promotes CBRH-7919 cell migration by lessening cell stiffness and increasing F-actin formation through up-regulation of CXCR4 expression. MSC-CM may therefore have a positive impact on cancer metastases and underlines a potential safety issue associated with clinical applications of MSCs.

An increase in CD3+CD4+CD25+ regulatory T cells after administration of umbilical cord-derived mesenchymal stem cells during sepsis

Sepsis remains an important cause of death worldwide, and vigorous immune responses during sepsis could be beneficial for bacterial clearance but at the price of collateral damage to self tissues. Mesenchymal stem cells (MSCs) have been found to modulate the immune system and attenuate sepsis. In the present study, MSCs derived from bone marrow and umbilical cord were used and compared. With a cecal ligation and puncture (CLP) model, the mechanisms of MSC-mediated immunoregulation during sepsis were studied by determining the changes of circulating inflammation-associated cytokine profiles and peripheral blood mononuclear cells 18 hours after CLP-induced sepsis. In vitro, bone marrow-derived MSCs (BMMSCs) and umbilical cord-derived MSCs (UCMSCs) showed a similar morphology and surface marker expression. UCMSCs had stronger potential for osteogenesis but lower for adipogenesis than BMMSCs. Compared with rats receiving PBS only after CLP, the percentage of circulating CD3+CD4+CD25+ regulatory T (Treg) cells and the ratio of Treg cells/T cells were elevated significantly in rats receiving MSCs. Further experiment regarding Treg cell function demonstrated that the immunosuppressive capacity of Treg cells from rats with CLP-induced sepsis was decreased, but could be restored by administration of MSCs. Compared with rats receiving PBS only after CLP, serum levels of interleukin-6 and tumor necrosis factor-α were significantly lower in rats receiving MSCs after CLP. There were no differences between BMMSCs and UCMSCs. In summary, this work provides the first in vivo evidence that administering BMMSCs or UCMSCs to rats with CLP-induced sepsis could increase circulating CD3+CD4+CD25+ Treg cells and Treg cells/T cells ratio, enhance Treg cell suppressive function, and decrease serum levels of interleukin-6 and tumor necrosis factor-α, suggesting the immunomodulatory association of Treg cells and MSCs during sepsis.

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.

Cells isolated from human glioblastoma multiforme express progesterone-induced blocking factor (PIBF)

Glioblastoma multiforme (GBM) is the most common and malignant tumor in the central nervous system. One of the contemporary hypotheses postulates that its pathogenesis is associated with the cancer stem cells (CSCs) which originate from mutations in the normal neural stem cells residing in their specific "niches." Simultaneously with its aggressive development the tumor suppresses the local immune system by different secreted and/or cell expressed factors. Progesterone-induced blocking factor (PIBF) is an immunomodulatory protein with known role in the regulation of the immune response in the reproductive system. Expression of PIBF has been described in some tumors as one of the factors suppressing the anti-tumor immunity. The aim of the present study was to check for the expression of PIBF from cells isolated from six GBMs. To characterize the cultured cells and to study the PIBF expression confocal microscopy, flow cytometry, ELISA, and real-time PCR were used. The results obtained showed expression of markers typical for cancer CSCs and secretion of interleukin 6 by the GBM-derived cultured cells. The results convincingly prove that PIBF is intracellularly expressed by the cultured cells from the all six GBM samples, and this fact is confirmed by three different methods-flow cytometry, confocal microscopy, and real-time PCR. This paper reports for the first time the expression of PIBF by GBM-derived cells cultured in vitro and reveals a new aspect of the immunosuppressive mechanism used by GBM in escaping the immune control.

Mesenchymal stem cells in treating autism: Novel insights

Autism spectrum disorders (ASDs) are complex neurodevelopmental disorders characterized by dysfunctions in social interactions, abnormal to absent verbal communication, restricted interests, and repetitive stereotypic verbal and non-verbal behaviors, influencing the ability to relate to and communicate. The core symptoms of ASDs concern the cognitive, emotional, and neurobehavioural domains. The prevalence of autism appears to be increasing at an alarming rate, yet there is a lack of effective and definitive pharmacological options. This has created an increased sense of urgency, and the need to identify novel therapies. Given the growing awareness of immune dysregulation in a significant portion of the autistic population, cell therapies have been proposed and applied to ASDs. In particular, mesenchymal stem cells (MSCs) possess the immunological properties which make them promising candidates in regenerative medicine. MSC therapy may be applicable to several diseases associated with inflammation and tissue damage, where subsequent regeneration and repair is necessary. MSCs could exert a positive effect in ASDs through the following mechanisms: stimulation of repair in the damaged tissue, e.g., inflammatory bowel disease; synthesizing and releasing anti-inflammatory cytokines and survival-promoting growth factors; integrating into existing neural and synaptic network, and restoring plasticity. The paracrine mechanisms of MSCs show interesting potential in ASD treatment. Promising and impressive results have been reported from the few clinical studies published to date, although the exact mechanisms of action of MSCs in ASDs to restore functions are still largely unknown. The potential role of MSCs in mediating ASD recovery is discussed in light of the newest findings from recent clinical studies.

Effect of human adipose tissue-derived mesenchymal-stem-cell bioactive materials on porcine embryo development

Human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) secrete bioactive materials that are beneficial for tissue repair and regeneration. In this study, we characterized human hAT-MSC bioactive material (hAT-MSC-BM), and examined the effect of hAT-MSC-BM on porcine embryo development. hAT-MSC-BM was enriched with several growth factors and cytokines, including fibroblast growth factor 2 (FGF2), vascular endothelial growth factor A (VEGFA), and interleukin 6 (IL6). Among the various concentrations and days of treatment tested, 10% hAT-MSC-BM treatment beginning on culture Day 4 provided the best environment for the in vitro growth of parthenogenetic porcine embryos. While the addition of 10% fetal bovine serum (FBS) increased the hatching rate and the total cell number of parthenogenetic porcine embryos compared with the control and hAT-MSC culture medium group, the best results were from the group cultured with 10% hAT-MSC-BM. Mitochondrial activity was also higher in the 10% hAT-MSC-BM-treated group. Moreover, the relative mRNA expression levels of development and anti-apoptosis genes were significantly higher in the 10% hAT-MSC-BM-treated group than in control, hAT-MSC culture medium, or 10% FBS groups, whereas the transcript abundance of an apoptosis gene was slightly lower. Treatment with 10% hAT-MSC-BM starting on Day 4 also improved the development rate and the total cell number of in vitro-fertilized embryos. This is the first report on the benefits of hAT-MSC-BM in a porcine embryo in vitro culture system. We conclude that hAT-MSC-BM is a new, alternative supplement that can improve the development of porcine embryos during both parthenogenesis and fertilization in vitro.