Neurogenic differentiation of murine and human adipose-derived stromal cells

The identification of cells capable of neuronal differentiation has great potential for cellular therapies. We examined whether murine and human adipose-derived adult stem (ADAS) cells can be induced to undergo neuronal differentiation. We isolated ADAS cells from the adipose tissue of adult BalbC mice or from human liposuction tissue and induced neuronal differentiation with valproic acid, butylated hydroxyanisole, insulin, and hydrocortisone. As early as 1-3 h after neuronal induction, the phenotype of ADAS cells changed towards neuronal morphology. Following neuronal induction, muADAS cells displayed immunocytochemical staining for GFAP, nestin and NeuN and huADAS cells displayed staining for intermediate filament M, nestin, and NeuN. Following neuronal induction of murine and human ADAS cells, Western blot analysis confirmed GFAP, nestin, and NeuN protein expression. Pretreatment with EGF and basic FGF augmented the neuronal differentiation of huADAS cells. The neuronal differentiation of stromal cells from adipose tissue has broad biological and clinical implications.     

Adipogenic differentiation of human adipose-derived stem cells grown as spheroids

Understanding the process of adipogenesis is critical if suitable therapeutics for obesity and related metabolic diseases are to be found. The current study presents proof of feasibility of creating a 3-D spheroid model using human adipose-derived stem cells (hASCs) and their subsequent adipogenic differentiation. hASC spheroids were formed atop an elastin-like polypeptide-polyethyleneimine (ELP-PEI) surface and differentiated using an adipogenic cocktail. Spheroids were matured in the presence of dietary fatty acids (linoleic or oleic acid) and evaluated based on functional markers including intracellular protein, CD36 expression, triglyceride accumulation, and PPAR-γ gene expression. Spheroid size was found to increase as the hASCs matured in the adipocyte maintenance medium, though the fatty acid treatment generally resulted in smaller spheroids compared to control. A stable protein content over the 10-day maturation period indicated contact-inhibited proliferation as well as minimal loss of spheroids during culture. Spheroids treated with fatty acids showed greater amounts of intracellular triglyceride content and greater expression of the key adipogenic gene, PPAR-γ. We also demonstrated that 3-D spheroids outperformed 2-D monolayer cultures in adipogenesis. We then compared the adipogenesis of hASC spheroids to that in 3T3-L1 spheroids and found that the triglyceride accumulation was less profound in hASC spheroids than that in 3T3-L1 adipocytes, correlated with smaller average spheroids, suggesting a relatively slower differentiation process. Taken together, we have shown the feasibility of adipogenic differentiation of patient-derived hASC spheroids, which with further development, may help elucidate key features in the adipogenesis process.     

In vivo differentiation of adipose-derived stem cells in an injectable poloxamer-octapeptide hybrid hydrogel

A hybrid hydrogel (PP) composed of Polomaxer-407 (PO) and octapeptide with amino acid sequence of KFEFKFEF (PE) was prepared to make a scaffold material incorporating PO's high and tunable mechanical strength and integrity with PE's superior bioactivity. Human adipose-derived mesenchymal stem cells (hASCs) were encapsulated into PE, PO and PP hydrogels respectively and injected subcutaneously at the dorsal neck area of nude mice. Adipose-like tissue regeneration was only observed in the mice injected with cell-encapsulated PP hydrogel. No adipose regeneration was found in the mice injected with PO or PE. Immunohistochemistry analysis with mouse anti-human nuclei monoclonal antibody demonstrated that the cells in the regenerated adipose-like tissue was originated from the injected hASCs. The growth of blood capillaries indicated that the regenerated adipose-like tissue was living tissue. In addition, human-originated cells were also found in nude mice skin. These cells were positive with mouse anti-human cells keratin antibody, suggesting that the injected hASCs migrated to the skin and differentiated into epithelial cells in vivo.     

Comparative proteomic analysis of human mesenchymal and embryonic stem cells: Towards the definition of a mesenchymal stem cell proteomic signature

Mesenchymal stem cells (MSC) are adult multipotential progenitors which have a high potential in regenerative medicine. They can be isolated from different tissues throughout the body and their homogeneity in terms of phenotype and differentiation capacities is a real concern. To address this issue, we conducted a 2‐DE gel analysis of mesenchymal stem cells isolated from bone marrow (BM), adipose tissue, synovial membrane and umbilical vein wall. We confirmed that BM and adipose tissue derived cells were very similar, which argue for their interchangeable use for cell therapy. We also compared human mesenchymal to embryonic stem cells and showed that umbilical vein wall stem cells, a neo‐natal cell type, were closer to BM cells than to embryonic stem cells. Based on these proteomic data, we could propose a panel of proteins which were the basis for the definition of a mesenchymal stem cell proteomic signature.     

Development of a rapid culture method to induce adipocyte differentiation of human bone marrow-derived mesenchymal stem cells

Human mesenchymal stem cells (hMSCs) derived from bone marrow are multipotent stem cells that can regenerate mesenchymal tissues such as adipose, bone or muscle. It is thought that hMSCs can be utilized as a cell resource for tissue engineering and as human models to study cell differentiation mechanisms, such as adipogenesis, osteoblastogenesis and so on. Since it takes 2-3 weeks for hMSCs to differentiate into adipocytes using conventional culture methods, the development of methods to induce faster differentiation into adipocytes is required. In this study we optimized the culture conditions for adipocyte induction to achieve a shorter cultivation time for the induction of adipocyte differentiation in bone marrow-derived hMSCs. Briefly, we used a cocktail of dexamethasone, insulin, methylisobutylxanthine (DIM) plus a peroxisome proliferator-activated receptor γ agonist, rosiglitazone (DIMRo) as a new adipogenic differentiation medium. We successfully shortened the period of cultivation to 7-8 days from 2-3 weeks. We also found that rosiglitazone alone was unable to induce adipocyte differentiation from hMSCs in vitro. However, rosiglitazone appears to enhance hMSC adipogenesis in the presence of other hormones and/or compounds, such as DIM. Furthermore, the inhibitory activity of TGF-β1 on adipogenesis could be investigated using DIMRo-treated hMSCs. We conclude that our rapid new culture method is very useful in measuring the effect of molecules that affect adipogenesis in hMSCs.     

Review of biophysical factors affecting osteogenic differentiation of human adult adipose-derived stem cells

Developing bone is subject to the control of a broad variety of influences in vivo. For bone repair applications, in vitro osteogenic assays are routinely used to test the responses of bone-forming cells to drugs, hormones, and biomaterials. Results of these assays are used to predict the behavior of bone-forming cells in vivo. Stem cell research has shown promise for enhancing bone repair. In vitro osteogenic assays to test the bone-forming response of stem cells typically use chemical solutions. Stem cell in vitro osteogenic assays often neglect important biophysical cues, such as the forces associated with regular weight-bearing exercise, which promote bone formation. Incorporating more biophysical cues that promote bone formation would improve in vitro osteogenic assays for stem cells. Improved in vitro osteogenic stimulation opens opportunities for “pre-conditioning” cells to differentiate towards the desired lineage. In this review, we explore the role of select biophysical factors—growth surfaces, tensile strain, fluid flow and electromagnetic stimulation—in promoting osteogenic differentiation of stem cells from human adipose. Emphasis is placed on the potential for physical microenvironment manipulation to translate tissue engineering and stem cell research into widespread clinical usage.     

茂丹通脉片含药血清体外诱导 S 分M化C为 内皮细胞的作用

目的：观察芪丹通脉片含药血清体外诱导大鼠骨髓间充质干细胞（MSCs）向内皮细胞分化的作用。方法：灌胃法制备芪丹通脉片含药血清和对照血清。采用密度梯度离心法分离和培养大鼠MSCs,取第三代MSCs,采用10wg／LVEGF预诱导24h后,分别加入15％芪丹通脉片含药血清与对照血清体外时MSCs诱导分化,至第7天,利用相差显微镜观察细胞形态改变,透射电镜观察细胞超微结构。免疫荧光方法检测内皮细胞特异性表面标志CD31、Ⅷ因子的表达。结果：至第7天,合15％芪丹通脉片合药血清组诱导后的MSCs形态发生明显改变,呈“卵石样”改变,透射电镜下细胞胞浆内可见Weible-Palade小体,共聚焦显微镜下可见CD31、Ⅷ因子阳性细胞。对照血清组MSCs形态仍呈长梭型,电镜下胞浆内无Weible-Palade小体,共聚焦显微镜下无CD31、Ⅷ因子阳性细胞。结论：益气活血复方芪丹通脉片含药血清具有体外诱导大鼠MSCs向内皮细胞定向分化的作用。     

Mesenchymal stem cells from human bone marrow or adipose tissue differently modulate mitogen-stimulated B-cell immunoglobulin production in vitro

Mesenchymal stem cells (MSC) have been characterized as multipotent cells which are able to differentiate into several mesodermal and nonmesodermal lineage cells and this feature along with their extensive growth and comprehensive immunomodulatory properties establish them as a promising tool for therapeutic applications, including cell-based tissue engineering and treatment of immune-mediated disorders. Although bone marrow (BM) is the most common MSC source, cells with similar characteristics have been shown to be present in several other adult tissues. Adipose tissue (AT), large quantities of which can be easily obtained, represents an attractive alternative to BM in isolating adipose tissue-derived MSC (AT-MSC). BM-MSCs and AT-MSCs share some immunomodulatory properties as they are both not inherently immunogenic and suppress the proliferation of alloantigen- or mitogen-stimulated T-cells. Our purpose was to comparatively examine under appropriate in vitro conditions, phenotypes, morphology and some functional properties of BM-MSCs and AT-MSCs, such as differentiation potential and especially the ability to suppress the immunoglobulin production by mitogen-stimulated B-cells. While the morphological, immunophenotypical, colony-forming and adipogenic characteristics of both types of cells were almost identical, AT-MSCs showed less potential for osteogenic differentiation than BM-MSCs. We found that AT-MSCs not only inhibited the Ig-production but also suppressed this B-cell function to a much greater extent compared to BM-MSC. This finding supports the potential role of AT-MSCs as an alternative to BM-MSCs for clinical purposes.     

In vivo injectable human adipose tissue regeneration by adipose-derived stem cells isolated from the fluid portion of liposuction aspirates

Liposuction aspirates separate into fatty and fluid portions. Cells isolated from the fatty portion are termed processed lipoaspirate (PLA) cells and isolated from the fluid portion termed liposuction aspirate fluid (LAF) cells, both of which contain adipose-derived stromal cells (ASCs). Here, we examined the biological differences between PLA and LAF cells and then tested the differentiation capacity of LAF cells in vivo. The cell surface marker and the multiple differentiation ability of fresh isolated PLA and LAF cells and which from passaged 3–5 were examined in vitro. LAF cells were then incubated in adipogenic medium, stained with 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine (DiI), mixed with fibrin glue then injected to nude mice; fibrin glue without cells was as a control. Three months later, the transplants were subjected to macroscopic observation and histological analysis. PLA and LAF cells were similar in growth kinetics, morphology, capacity for differentiation, and surface marker profiles. After plating, both PLA and LAF cells showed increased expression of CD29, CD44, CD133 and HLA DR and decreased expression of CD34. In vivo differentiation assay showed the mixture of LAF cells and fibrin glue formed adipose tissue which contained red fluorescent DiI-positive adipocytes. LAF cells can be harvested more easily than PLA cells. The in vivo adipogenic capacity suggested LAF cells would be useful and valuable for cell-based therapies and soft tissue reconstruction.     

Growth and osteogenic differentiation of adipose-derived and bone marrow-derived stem cells on chitosan and chitooligosaccharide films

Very low molecular weight chitooligosaccharide (COS, 1.4 kDa) and high molecular weight chitosan (1000 kDa) were comparatively studied in terms of physical and biological characteristics. Thin films of COS, chitosan and gelatin were prepared and crosslinked by dehydrothermal treatment at 140 °C for 24 h. COS film presented more hydrophilic property than chitosan film. Behaviors of rat adipose-derived stem cells (ASCs) and bone marrow-derived stem cells (MSCs) were investigated on COS and chitosan films, comparing to those on gelatin film. The results on cell spreading suggested that both ASCs and MSCs preferred to attach on COS film than chitosan film with 6–7 times larger cell areas. Numbers of both stem cells proliferated on COS film were approximately 3-fold higher than those on chitosan film. In addition, COS film enhanced osteogenic differentiating potential of MSCs, as observed from the alkaline phosphatase activity and calcium deposition. Therefore, in this work, COS was shown to be a more favorable material for the growth and osteogenic differentiation of both ASCs and MSCs, compared to high molecular weight chitosan.     

ESET histone methyltransferase regulates osteoblastic differentiation of mesenchymal stem cells during postnatal bone development

To investigate the effects of histone methyltransferase ESET (also known as SETDB1) on bone metabolism, we analyzed osteoblasts and osteoclasts in ESET knockout animals, and performed osteogenesis assays using ESET-null mesenchymal stem cells. We found that ESET deletion severely impairs osteoblast differentiation but has no effect on osteoclastogenesis, that co-transfection of ESET represses Runx2-mediated luciferase reporter while siRNA knockdown of ESET activates the luciferase reporter in mesenchymal cells, and that ESET is required for postnatal expression of Indian hedgehog protein in the growth plate. As the bone phenotype in ESET-null mice is 100% penetrant, these results support ESET as a critical regulator of osteoblast differentiation during bone development.     

Osteogenic differentiation of human adipose tissue-derived stromal cells (hASCs) in a porous three-dimensional scaffold

Recent studies have shown that liposuction aspirates from rat, rabbit, mouse, and human sources contain pluripotent adipose tissue-derived stromal cells (ASCs) that can differentiate into various mesodermal cell types, including osteoblasts, myoblasts, chondroblasts, and preadipocytes. To develop a research model for autologous bone tissue engineering, we isolated ASCs from human liposuction aspirates (hASCs) and induced their osteogenic differentiation in three-dimensional poly(dl-lactic-co-glycolic acid) (PLGA) scaffolds. Human liposuction aspirates were proteolytically digested and centrifuged to obtain hASCs. After primary culture in control media and expansion to three passages, the cells were seeded in two-dimensional plates or three-dimensional PLGA scaffolds and cultured in osteogenic media for 4 weeks. In two-dimensional culture, osteogenesis was assessed by RT-PCR analysis of the osteogenic-specific bone sialoprotein mRNA, by alkaline phosphatase staining, and by von Kossa staining. In three-dimensional culture, osteogenesis was assessed by von Kossa and alizarine red S staining at 1, 2, and 4 weeks following osteogenic induction. hASCs incubated in two-dimensional osteogenic media stained positively for alkaline phosphatase and with von Kossa stain after 2 weeks of differentiation. Expression of the osteogenesis-specific bone sialoprotein gene was detected by RT-PCR after 2 weeks of differentiation. PLGA scaffolds seeded with hASCs showed multiple calcified extracellular matrix nodules by von Kossa and alizarine red S staining after 2 weeks of differentiation. In conclusion, the authors identified an osteogenic potential of hASCs and demonstrated osteogenic differentiation of hASCs into an osteogenic lineage in three-dimensional PLGA scaffolds.     

In vitro differentiation of human umbilical cord blood-derived mesenchymal stem cells into hepatocyte-like cells

In addition to long-term self-renewal capability, human mesenchymal stem cells (MSCs) possess versatile differentiation potential ranging from mesenchyme-related multipotency to neuroectodermal and endodermal competency. Of particular concern is hepatogenic potential that can be used for liver-directed stem cell therapy and transplantation. In this study, we have investigated whether human umbilical cord blood (UCB)-derived MSCs are also able to differentiate into hepatocyte-like cells. MSCs isolated from UCB were cultured under the pro-hepatogenic condition similar to that for bone marrow (BM)-derived MSCs. Expression of a variety of hepatic lineage markers was analyzed by flow cytometry, RT-PCR, Western blot, and immunofluorescence. The functionality of differentiated cells was assessed by their ability to incorporate DiI-acetylated low-density lipoprotein (DiI-Ac-LDL). As the cells were morphologically transformed into hepatocyte-like cells, they expressed Thy-1, c-Kit, and Flt-3 at the cell surface, as well as albumin, alpha-fetoprotein, and cytokeratin-18 and 19 in the interior. Moreover, about a half of the cells were found to acquire the capability to transport DiI-Ac-LDL. Based on these observations, and taking into account immense advantages of UCB over other stem cell sources, we conclude that UCB-derived MSCs retain hepatogenic potential suitable for cell therapy and transplantation against intractable liver diseases.     

Short-term effects of 7-ketocholesterol on human adipose tissue mesenchymal stem cells in vitro

Oxysterols comprise a very heterogeneous group derived from cholesterol through enzymatic and non-enzymatic oxidation. Among them, 7-ketocholesterol (7-KC) is one of the most important. It has potent effects in cell death processes, including cytoxicity and apoptosis induction. Mesenchymal stem cells (MSCs) are multipotent cells characterized by self-renewal and cellular differentiation capabilities. Very little is known about the effects of oxysterols in MSCs. Here, we describe the short-term cytotoxic effect of 7-ketocholesterol on MSCs derived from human adipose tissue. MSCs were isolated from adipose tissue obtained from two young, healthy women. After 24 h incubation with 7-KC, mitochondrial hyperpolarization was observed, followed by a slight increase in the level of apoptosis and changes in actin organization. Finally, the IC₅₀ of 7-KC was higher in these cells than has been observed or described in other normal or cancer cell lines.