Human amnion-derived mesenchymal stem cells are a potential source for uterine stem cell therapy

Effect of pregnancy on isolation efficiency and in vitro proliferation of equine peripheral-blood derived mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) have regenerative and immunomodulatory potential and may be used to treat injured tissues. Pregnancy has been associated with increased MSCs in the peripheral circulation in multiple species, but to date, there are no reports on this matter in horses. This study aimed to evaluate the effect of pregnancy on isolation efficiency and proliferation capacity of equine MSCs derived from the peripheral blood (PB) of mares. Venous blood samples were collected at the 11th month of gestation and 1 month after delivery from clinically healthy Arabian mares that presented normal pregnancies. Blood samples were processed for in vitro cellular culture and hormonal and metabolic profiles. MSCs were isolated and characterized by trilineage differentiation potential, immunophenotyping, analyzed by gene sequencing and proliferation assays. The isolation of peripheral blood mononuclear cells (PBMCs) of pregnant mares were associated with higher isolation efficiency and proliferative capacity of MSCs derived from peripheral blood (PB-MSCs) recovered pre-partum than those isolated post-partum. Although fetal gender, parity, 5α-reduced pregnanes, insulin, and cortisol were shown to affect cellular proliferation, individual factors and the small population studied must be considered. This study suggests that PB-MSCs from pregnant mares could be a valuable alternative source of MSCs for therapeutic purposes.

Isolation of extracellular vesicles from bitch's amnion-derived cells culture and their CD59 expression: Preliminary results

Extracellular vesicles (EVs) are small spherical particles surrounded by a membrane with an unusual lipid composition and a striking cholesterol/phospholipidic ratio. About 2000 lipid and 3500 protein species were identified in EVs secreted by different cell sources. EVs mediate cell to cell communication in proximity to or distant from the cell of origin. In particular, it was suggested that they represent modulators of multiple processes during pregnancy. The aim of this study was to identify the presence of EVs in canine amnion-derived cells (ASCs) culture and the expression of CD 59 on their surface. Amniotic membrane was collected in PBS with antibiotics added from 2 bitches during elective caesarean section. Cells culture was prepared and EVs were isolated. EVs were used to evaluate CD59 expression by flow cytofluorimetry. We found that the majority of EVs expressed CD59. Our results could increase the knowledge about the complex mechanisms that regulate the pregnancy in the bitch.

Extraembryonic Mesenchymal Stromal/Stem Cells in Liver Diseases: A Critical Revision of Promising Advanced Therapy Medicinal Products

Liver disorders have been increasing globally in recent years. These diseases are associated with high morbidity and mortality rates and impose high care costs on the health system. Acute liver failure, chronic and congenital liver diseases, as well as hepatocellular carcinoma have been limitedly treated by whole organ transplantation so far. But novel treatments for liver disorders using cell-based approaches have emerged in recent years. Extra-embryonic tissues, including umbilical cord, amnion membrane, and chorion plate, contain multipotent stem cells. The pre-sent manuscript discusses potential application of extraembryonic mesenchymal stromal/stem cells, focusing on the management of liver diseases. Extra-embryonic MSC are characterized by robust and constitutive anti-inflammatory and anti-fibrotic properties, indicating as therapeutic agents for inflammatory conditions such as liver fibrosis or advanced cirrhosis, as well as chronic inflammatory settings or deranged immune responses.

Therapeutic Aspects of Mesenchymal Stem Cell-Based Cell Therapy with a Focus on Human Amniotic Epithelial Cells in Multiple Sclerosis: A Mechanistic Review

Multiple sclerosis (MS) is an inflammatory disease of central nervous system (CNS). The mmune system plays an important role in its pathogenesis. Current treatments are unable to cure patients and prevent the progression of MS lesions. Stem cell-based cell therapy has opened a new window for MS treatment. Stem cells regulate immune responses and improve axonal remyelination. Stem cells can be obtained from different origins such as embryonic, neural, bone marrow, and adipose tissues. But yet there is a challenge for the selection of the best cell source for stem cell therapy. Mesenchymal stem cells (MSCs) are a type of stem cell obtained from different origins and have significant immunomodulatory effects on the immune system. The increasing evidence have suggested that umbilical cord and adipose tissue can be a suitable source for isolation of MSCs. Moreover, human amniotic epithelial cells (hAECs) as novel stem cell origins by having immunoregulatory effects, regenerative effects, and less capacity of antigenicity can be a candidate for MS treatment. This review discussed the mechanistic effects of MSCs with a focus on human amniotic epithelial cells, which can be used to treatment and improvement of outcome in MS disease.

Characteristics and Therapeutic Potential of Human Amnion-Derived Stem Cells

Stem cells including embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs) and adult stem cells (ASCs) are able to repair/replace damaged or degenerative tissues and improve functional recovery in experimental model and clinical trials. However, there are still many limitations and unresolved problems regarding stem cell therapy in terms of ethical barriers, immune rejection, tumorigenicity, and cell sources. By reviewing recent literatures and our related works, human amnion-derived stem cells (hADSCs) including human amniotic mesenchymal stem cells (hAMSCs) and human amniotic epithelial stem cells (hAESCs) have shown considerable advantages over other stem cells. In this review, we first described the biological characteristics and advantages of hADSCs, especially for their high pluripotency and immunomodulatory effects. Then, we summarized the therapeutic applications and recent progresses of hADSCs in treating various diseases for preclinical research and clinical trials. In addition, the possible mechanisms and the challenges of hADSCs applications have been also discussed. Finally, we highlighted the properties of hADSCs as a promising source of stem cells for cell therapy and regenerative medicine and pointed out the perspectives for the directions of hADSCs applications clinically.

Identification of differentially expressed genes by single-cell transcriptional profiling of umbilical cord and synovial fluid mesenchymal stem cells

The purpose of this study was to measure the heterogeneity in human umbilical cord–derived mesenchymal stem cells (hUC‐MSCs) and human synovial fluid–derived mesenchymal stem cells (hSF‐MSCs) by single‐cell RNA‐sequencing (scRNA‐seq). Using Chromium™ technology, scRNA‐seq was performed on hUC‐MSCs and hSF‐MSCs from samples that passed our quality control checks. In order to identify subgroups and activated pathways, several bioinformatics tools were used to analyse the transcriptomic profiles, including clustering, principle components analysis (PCA), t‐Distributed Stochastic Neighbor Embedding (t‐SNE), gene set enrichment analysis, as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. scRNA‐seq was performed on the two sample sets. In total, there were 104 761 163 reads for the hUC‐MSCs and 6 577 715 for the hSF‐MSCs, with >60% mapping rate. Based on PCA and t‐SNE analyses, we identified 11 subsets within hUC‐MSCs and seven subsets within hSF‐MSCs. Gene set enrichment analysis determined that there were 533, 57, 32, 44, 10, 319, 731, 1037, 90, 25 and 230 differentially expressed genes (DEGs) in the 11 subsets of hUC‐MSCs and 204, 577, 30, 577, 16, 57 and 35 DEGs in the seven subsets of hSF‐MSCs. scRNA‐seq was not only able to identify subpopulations of hUC‐MSCs and hSF‐MSCs within the sample sets, but also provided a digital transcript count of hUC‐MSCs and hSF‐MSCs within a single patient. scRNA‐seq analysis may elucidate some of the biological characteristics of MSCs and allow for a better understanding of the multi‐directional differentiation, immunomodulatory properties and tissue repair capabilities of MSCs.

The Immunomodulatory Properties of Amniotic Cells: The Two Sides of the Coin

Among the many cell types useful in developing therapeutic treatments, human amniotic cells from placenta have been proposed as valid candidates. Both human amniotic epithelial and mesenchymal stromal cells, and the conditioned medium generated from their culture, exert multiple immunosuppressive activities. Indeed, they inhibit T and B cell proliferation, suppress inflammatory properties of monocytes, macrophages, dendritic cells, neutrophils, and natural killer cells, while promoting induction of cells with regulatory functions such as regulatory T cells and anti-inflammatory M2 macrophages. These properties have laid the foundation for their use for the treatment of inflammatory-based diseases, and encouraging results have been obtained in different preclinical disease models where exacerbated inflammation is present. Moreover, an immune-privileged status of amniotic cells has been often highlighted. However, even if long-term engraftment of amniotic cells has been reported into immunocompetent animals, only few cells survive after infusion. Furthermore, amniotic cells have been shown to be able to induce immune responses in vivo and, under specific culture conditions, they can stimulate T cell proliferation in vitro. Although immunosuppressive properties are a widely recognized characteristic of amniotic cells, immunogenic and stimulatory activities appear to be less reported, sporadic events. In order to improve therapeutic outcome, the mechanisms responsible for the suppressive versus stimulatory activity need to be carefully addressed. In this review, both the immunosuppressive and immunostimulatory activity of amniotic cells will be discussed.

Effects of hPMSCs on granulosa cell apoptosis and AMH expression and their role in the restoration of ovary function in premature ovarian failure mice

Background

This study was performed to determine the effects of human placenta mesenchymal stem cell (hPMSC) transplantation on granulosa cell apoptosis and anti-Müllerian hormone (AMH) and follicle-stimulating hormone receptor (FSHR) expression in autoimmune drug-induced premature ovarian failure (POF) mice. The aim of this research is to investigate the mechanisms of hPMSCs on ovarian reserve capacity.

Methods

The POF mice model was established by injection of zona pellucida 3 peptide (pZP3). hPMSC transplantation was conducted by intravenous injection into mice following pZP3 treatment. The follicle number was examined by histopathology. The serum levels of FSH, LH, E₂, AMH and anti-zona pellucida antibody (AzpAb) were measured by enzyme-linked immunosorbent assay. AMH and FSHR expression in the ovary was analyzed by immunohistochemistry and western blot analysis. Granulosa cell apoptosis of the ovaries was examined by In Situ Cell Death Detection Kit. Granulosa cells were isolated and treated with SiAmh interference and hPMSC supernatant to observe the effects of AMH expression on granulosa cell apoptosis in vitro.

Results

The results showed that hPMSC transplantation can significantly recover the estrus cycle in the POF group. Morphological staining showed that the basal follicles and sinus follicles after hPMSC transplantation were higher in POF mice than in those without treatment, and the follicle number was significantly decreased with atresia. The serum levels of FSH, LH and AzpAb in the hPMSC transplantation group were reduced considerably, but the E₂ and AMH levels were significantly increased. After hPMSC transplantation, the AMH and FSHR expression in ovarian tissue was significantly higher than in the POF group as determined by immunochemistry and western blot analysis. The FSHR expression was shown in granulosa cells only, and FSHR expression increases with AMH expressed in the ovary; granulosa cell apoptosis was decreased following hPMSC transplantation. The same results were observed from the in-vitro study.

Conclusions

hPMSC transplantation can significantly improve the serum levels of high gonadotropin and low estrogen of POF mice, promote follicular development, inhibit excessive follicular atresia and granulosa cell apoptosis, and improve the ovarian reserve capacity. The mechanism may be achieved by increasing the expression of AMH and FSHR in ovaries.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0745-5) contains supplementary material, which is available to authorized users.

Human amnion-derived mesenchymal stem cells protect against UVA irradiation-induced human dermal fibroblast senescence, in vitro

The aim of the present study was to determine if human amnion-derived mesenchymal stem cells (HAMSCs) exert a protective effect on ultraviolet A (UVA) irradiation-induced human dermal fibroblast (HDF) senescence. A senescence model was constructed as follows: HDFs (104–106 cells/well) were cultured in a six-well plate in vitro and then exposed to UVA irradiation at 9 J/cm2 for 30 min. Following the irradiation period, HDFs were co-cultured with HAMSCs, which were seeded on transwells. A total of 72 h following the co-culturing, senescence-associated β-galactosidase staining was performed and reactive oxygen species (ROS) content and mitochondrial membrane potential (Δψm) were detected in the HDFs via flow cytometric analysis. The results demonstrated that the percentage of HDFs, detected via staining with X-gal, were markedly decreased when co-cultured with human HAMSCs, compared with the group that were not co-cultured. The ROS content was decreased and the mitochondrial membrane potential (Δψm) recovered in cells treated with UVA and HAMSCs, compared with that of cells treated with UVA alone. Reverse transcription-quantitative polymerase chain reaction revealed the significant effects of HAMSCs on the HDF senescence marker genes p53 and matrix metalloproteinase-1 mRNA expression. In addition to this, western blot analysis verified the effects of HAMSCs on UVA induced senescence, providing a foundation for novel regenerative therapeutic methods. Furthermore, the results suggested that activation of the extracellular-signal regulated kinase 1/2 mitogen activated protein kinase signal transduction pathway, is essential for the HAMSC-mediated UVA protective effects. The decrease in ROS content additionally indicated that HAMSCs may exhibit the potential to treat oxidative stress-mediated UVA skin senescence in the future.

Comparative study of allogenic and xenogeneic mesenchymal stem cells on cisplatin-induced acute kidney injury in Sprague-Dawley rats

Background

The paracrine and regenerative activities of mesenchymal stem cells (MSCs) may vary with different stem cell sources. The aim of the present study is to compare the effects of MSCs from different sources on acute kidney injury (AKI) induced by cisplatin and their influence on renal regeneration.

Methods

A single intraperitoneal injection of cisplatin (5 mg/kg) was used to induce AKI in 120 Sprague-Dawley rats. Rats were treated with either rat bone marrow stem cells (rBMSCs), human adipose tissue-derived stem cells (hADSCs), or human amniotic fluid-derived stem cells (hAFSCs). 5 × 10⁶ MSCs of different sources were administered through rat tail vein in a single dose, 24 hours after cisplatin injection. Within each group, rats were sacrificed at the 4th, 7th, 11th, and 30th day after cisplatin injection. Serum creatinine, BUN, and renal tissue oxidative stress parameters were measured. Renal tissue was scored histopathologically for evidence of injury, regeneration, and chronicity. Immunohistochemistry was also done using Ki67 for renal proliferative activity evaluation.

Results

MSCs of the three sources were able to ameliorate cisplatin-induced renal function deterioration and tissue damage. The rat BMSCs-treated group had the lowest serum creatinine by day 30 (0.52 ± 0.06) compared to hADSCs and hAFSCs. All MSC-treated groups had nearly equal antioxidant activity as indicated by the decreased renal tissue malondialdehyde (MDA) and increased reduced glutathione (GSH) level and superoxide dismutase (SOD) activity at different time intervals. Additionally, all MSCs improved injury and regenerative scores. Rat BMSCs had the highest count and earliest proliferative activity in the renal cortex by day 7 as identified by Ki67; while, hAFSCs seem to have the greatest improvement in the regenerative and proliferative activities with a higher count of renal cortex Ki67-positive cells at day 11 and with the least necrotic lesions.

Conclusions

Rat BMSCs, hADSCs, and hAFSCs, in early single IV dose, had a renoprotective effect against cisplatin-induced AKI, and were able to reduce oxidative stress markers. Rat BMSCs had the earliest proliferative activity by day 7; however, hAFSCs seemed to have the greatest improvement in the regenerative activities. Human ADSCs were the least effective in the terms of proliferative and regenerative activities.

Amniotic membrane-derived mesenchymal cells and their conditioned media: potential candidates for uterine regenerative therapy in the horse

Amniotic membrane-derived mesenchymal cells (AMCs) are considered suitable candidates for a variety of cell-based applications. In view of cell therapy application in uterine pathologies, we studied AMCs in comparison to cells isolated from the endometrium of mares at diestrus (EDCs) being the endometrium during diestrus and early pregnancy similar from a hormonal standpoint. In particular, we demonstrated that amnion tissue fragments (AM) shares the same transcriptional profile with endometrial tissue fragments (ED), expressing genes involved in early pregnancy (AbdB-like Hoxa genes), pre-implantantion conceptus development (Erα, PR, PGRMC1 and mPR) and their regulators (Wnt7a, Wnt4a). Soon after the isolation, only AMCs express Wnt4a and Wnt7a. Interestingly, the expression levels of prostaglandin-endoperoxide synthase 2 (PTGS2) were found greater in AM and AMCs than their endometrial counterparts thus confirming the role of AMCs as mediators of inflammation. The expression of nuclear progesterone receptor (PR), membrane-bound intracellular progesterone receptor component 1 (PGRMC1) and membrane-bound intracellular progesterone receptor (mPR), known to lead to improved endometrial receptivity, was maintained in AMCs over 5 passages in vitro when the media was supplemented with progesterone. To further explore the potential of AMCs in endometrial regeneration, their capacity to support resident cell proliferation was assessed by co-culturing them with EDCs in a transwell system or culturing in the presence of AMC-conditioned medium (AMC-CM). A significant increase in EDC proliferation rate exhibited the crucial role of soluble factors as mediators of stem cells action. The present investigation revealed that AMCs, as well as their derived conditioned media, have the potential to improve endometrial cell replenishment when low proliferation is associated to pregnancy failure. These findings make AMCs suitable candidates for the treatment of endometrosis in mares.

Human Amnion-Derived Stem Cells Have Immunosuppressive Properties on NK Cells and Monocytes

Human amnion-derived cells are considered to be a promising alternative cell source for their potential clinical use in tissue engineering and regenerative medicine because of their proliferation and differentiation ability. The cells can easily be obtained from human amnion, offering a potential source without medical intervention. It has been proven that human amnion-derived cells express immunosuppressive factors CD59 and HLA-G, implying that they may have an immunosuppressive function. To assess the immunosuppressive activity, we investigated the effect of human amnion-derived cells on NK cell and monocyte function. Amnion-derived cells inhibited the cytotoxicity of NK cells to K562 cells. The inhibition depended on the NK/amnion-derived cell ratio. The inhibition of NK cytotoxicity was recovered by continuous culturing without amnion-derived cells. The inhibition of NK cytotoxicity was related to the downregulation of the expression of the activated NK receptors and the production of IFN-γ, as well as the upregulation of the expression of IL-10 and PGE2 in human amnion-derived cells. The addition of antibody to IL-10 or PGE2 inhibitor tended to increase NK cytotoxicity. IL-10 and PGE2 might be involved in the immunosuppressive activity of amniotic cells toward NK cells. Amniotic cells also suppressed the activity of cytokine production in monocytes analyzed with TNF-α and IL-6. These data suggested that amniotic cells have immunosuppressive activity.

Derivation of human decidua-like cells from amnion and menstrual blood

We induced differentiation of human amnion-derived mesenchymal stem cells (AMCs) and menstrual blood-derived mesenchymal stem cells (MMCs) into endometrial stroma-like cells, which could be useful for cell therapy to support embryo implantation. Interestingly, the expression patterns of surface markers were similar among AMCs, MMCs, and endometrial stromal cells. In addition, whereas treatment with estrogen and progesterone was not very effective for decidualizing AMCs and MMCs, treatment with 8-Br-cAMP prompted remarkable morphological changes in these cells as well as increased expression of decidualization markers (prolactin and insulin-like growth factor binding protein-1) and attenuated expression of surface markers unique to mesenchymal stem cells. These results demonstrated that bone marrow-derived stem cells, which are considered a potential source of endometrial progenitor cells, as well as AMCs and MMCs show in vitro decidualization potential, which is characteristic of endometrial stromal cells.

Comparative analysis of human mesenchymal stem cells from bone marrow, adipose tissue, and umbilical cord blood as sources of cell therapy

Various source-derived mesenchymal stem cells (MSCs) have been considered for cell therapeutics in incurable diseases. To characterize MSCs from different sources, we compared human bone marrow (BM), adipose tissue (AT), and umbilical cord blood-derived MSCs (UCB-MSCs) for surface antigen expression, differentiation ability, proliferation capacity, clonality, tolerance for aging, and paracrine activity. Although MSCs from different tissues have similar levels of surface antigen expression, immunosuppressive activity, and differentiation ability, UCB-MSCs had the highest rate of cell proliferation and clonality, and significantly lower expression of p53, p21, and p16, well known markers of senescence. Since paracrine action is the main action of MSCs, we examined the anti-inflammatory activity of each MSC under lipopolysaccharide (LPS)-induced inflammation. Co-culture of UCB-MSCs with LPS-treated rat alveolar macrophage, reduced expression of inflammatory cytokines including interleukin-1α (IL-1α), IL-6, and IL-8 via angiopoietin-1 (Ang-1). Using recombinant Ang-1 as potential soluble paracrine factor or its small interference RNA (siRNA), we found that Ang-1 secretion was responsible for this beneficial effect in part by preventing inflammation. Our results demonstrate that primitive UCB-MSCs have biological advantages in comparison to adult sources, making UCB-MSCs a useful model for clinical applications of cell therapy.

Long-term immunomodulatory effect of amniotic stem cells in an Alzheimer's disease model

Amyloid beta (Aβ) plays a major role in Alzheimer's disease (AD), and neuroinflammatory processes mediated by Aβ plaque-induced microglial cells and astrocytes contribute to AD pathogenesis. The present study examined human placenta amniotic membrane-derived mesenchymal stem cells (AMSCs), which have potent immunomodulatory and paracrine effects in a Tg2576 (APPswe) transgenic mouse model of AD. AMSCs secreted high levels of transforming growth factor-β under in vitro inflammatory environment conditions. Six weeks after the intravenous injection of AMSCs, APPswe mice showed evidence of improved spatial learning, which significantly correlated with the observation of fewer Aβ plaques in brain. The number of ED1-positive phagocytic microglial cells associated with Aβ plaques was higher in AMSC-injected mice than in phosphate-buffered saline-injected mice, and the level of Aβ-degrading enzymes (matrix metallopeptidase-9 and insulin-degrading enzyme) was also significantly higher. Furthermore, the level of proinflammatory cytokines, interleukin-1 and tumor necrosis factor-α, was lower and that of anti-inflammatory cytokines, interleukin-10 and transforming growth factor-β, was higher in AMSC-injected mice than phosphate-buffered saline-injected mice. These effects lasted until 12 weeks after AMSC injection. Taken together, these results collectively suggest that injection of AMSCs might show significant long-lasting improvement in AD pathology and memory function via immunomodulatory and paracrine mechanisms.

Tissue engineering for the oncologic urinary bladder

Urinary diversion after radical cystectomy in patients with bladder cancer normally takes the form of an ileal conduit or neobladder. However, such diversions are associated with a number of complications including increased risk of infection. A plausible alternative is the construction of a neobladder (or bladder tissue) in vitro using autologous cells harvested from the patient. Biomaterials can be used as a scaffold for naturally occurring regenerative stem cells to latch onto to regrow the bladder smooth muscle and epithelium. Such engineered tissues show great promise in urologic tissue regeneration, but are faced with a number of challenges. For example, the differentiation mesenchymal stem cells from various sources can be difficult and the smooth muscle cells formed do not precisely mimic the natural cells.

Progesterone enhances immunoregulatory activity of human mesenchymal stem cells via PGE2 and IL-6

PROBLEM

Progesterone (P4) plays a central role in the establishment and maintenance of pregnancy. It also has profound effects on the regulation of immune responses. Mesenchymal stem cells (MSCs), which are thought to have the ability to modulate immunocyte activation, are present in human endometrium and deciduas and highly express progesterone receptor (PR). Especially, during pregnancy, both P4 and MSCs are present and regulatively changed at the fetal-maternal interface, but the effect of P4 on the MSCs remains unknown. Therefore, in this study, we investigated the effects of P4 on the immunomodulatory ability of MSCs and the underlying mechanisms.

METHOD OF STUDY

Mesenchymal stem cells were obtained from human umbilical cords. The effects of P4 on the cell morphology, phenotype, proliferation, apoptosis, and expression levels of cytokine and protein were examined.

RESULTS

Progesterone did not affect the phenotype, morphology, proliferation, and apoptosis of MSCs, but promoted the production of PGE2 and IL-6 in MSCs. Furthermore, the up-regulation of PGE2 and IL-6 was related to the activation of p38 and NF-κB.

CONCLUSIONS

Progesterone enhances immunomodulatory function of MSCs through up-regulation of PGE2 and IL-6. The data suggest that P4-regulated MSCs may play a crucial role in modulating the local immune balance of fetal-maternal interface.

Both freshly prepared and frozen-stored amniotic membrane cells express the complement inhibitor CD59

Amniotic membrane proved to be very effective tool in the treatment of a number of ocular surface diseases. The amniotic membrane, however, has to be stored before its transplantation onto the ocular surface followed by mandatory serologic control in order to exclude the transmission of certain viruses. Therefore it is most important to study if cryopreservation of the membrane affects cell surface expression of the molecules. We measured cell surface expression of CD59, a membrane-bound complement inhibitor on the cells of freshly prepared and cryopreserved amniotic membrane. Cells of amniotic membrane were separated mechanically. Epithelial and mesenchymal cells were identified by the intracellular expression of nanog and the cell surface ICAM1 positivity, respectively. Multicolor flow cytometric immunophenotyping was used for determination of the CD59 expression. CellQuest-Pro software program (Becton Dickinson) was used both for measurements and analysis. CD59-positive cells could be detected in all investigated samples and in all investigated cell types, although the expression level of CD59 differed. CD59 was expressed both on freshly prepared and frozen-stored samples. Higher level of CD59 was detected on ICAM1+ mesenchymal cells than on nanog+ epithelial cells. Our findings indicate that amniotic membranes maintain their complement inhibiting capacity after cryopreservation.

Same or not the same? Comparison of adipose tissue-derived versus bone marrow-derived mesenchymal stem and stromal cells

Mesenchymal stem/stromal cells (MSCs) comprise a heterogeneous population of cells with multilineage differentiation potential, the ability to modulate oxidative stress, and secrete various cytokines and growth factors that can have immunomodulatory, angiogenic, anti-inflammatory and anti-apoptotic effects. Recent data indicate that these paracrine factors may play a key role in MSC-mediated effects in modulating various acute and chronic pathological conditions. MSCs are found in virtually all organs of the body. Bone marrow-derived MSCs (BM-MSCs) were discovered first, and the bone marrow was considered the main source of MSCs for clinical application. Subsequently, MSCs have been isolated from various other sources with the adipose tissue, serving as one of the alternatives to bone marrow. Adipose tissue-derived MSCs (ASCs) can be more easily isolated; this approach is safer, and also, considerably larger amounts of ASCs can be obtained compared with the bone marrow. ASCs and BM-MSCs share many biological characteristics; however, there are some differences in their immunophenotype, differentiation potential, transcriptome, proteome, and immunomodulatory activity. Some of these differences may represent specific features of BM-MSCs and ASCs, while others are suggestive of the inherent heterogeneity of both BM-MSC and ASC populations. Still other differences may simply be related to different isolation and culture protocols. Most importantly, despite the minor differences between these MSC populations, ASCs seem to be as effective as BM-MSCs in clinical application, and, in some cases, may be better suited than BM-MSCs. In this review, we will examine in detail the ontology, biology, preclinical, and clinical application of BM-MSCs versus ASCs.

Human amniotic membrane-derived mesenchymal stem cells labeled with superparamagnetic iron oxide nanoparticles: the effect on neuron-like differentiation in vitro

Mesenchymal stem cells (MSCs) have the potential for self-renewal and multipotential differentiation to regenerate damaged tissues or recover functional absence in diseases. Superparamagnetic iron oxide nanoparticles (SPIONs) are used as contrast agents in magnetic resonance imaging (MRI) for labeling cells in vitro and for tracking SPION-labeled cells after transplantation in vivo. Human amniotic membrane-derived mesenchymal stem cells (hAM-dMSCs) have the capacity for neuron-like differentiation that could be used to cure central nervous system (CNS) diseases. The study investigated the impacts of cytotoxicity of SPIONs on neuron-like differentiation of hAM-dMSCs in both single (1×) and multiple (4×) SPIONs-labeled methods. hAM-dMSCs could be efficiently labeled at safe concentrations of SPIONs (≤14 μg/ml) without significantly affecting their viability (>80% after a MTT assay), special surface antigens (CD29, CD44, CD90, CD105 through flow cytometry), and neuron-like differentiation (nestin and neuron-specific enolase through immunocytochemistry and reverse transcription polymerase chain reaction). Compared with multiple (4×) SPION-labeled methods, a single (1×) SPION-labeled method avoided multiple SPION-labeled hAM-dMSCs and minimized the impact of cytotoxicity of SPIONs on neuron-like differentiation of hAM-dMSCs. Under safe concentrations of SPIONs, a single (1×) SPION-labeled method provided appropriate viability for SPIONs-labeled hAM-dMSCs and facilitated the MRI evaluation of hAM-dMSCs after transplantation.

Culture and identification of human amniotic mesenchymal stem cells

OBJECTIVE

To establish the method of isolation, purification, and identification of human amniotic mesenchymal stem cells (hAMSCs).

METHODS

hAMSCs were isolated from human amniotic membrane by trypsin-collagenase digestion, and cultured in Dulbecco's modified Eagle's medium/F12 medium supplemented with 10% fetal bovine serum. Phenotypic characteristics of these cells were analyzed by means of immunocytochemistry and flow cytometry.

RESULTS

The cells successfully isolated from human amniotic membrane expressed representative mesenchymal cell surface markers CD44, CD90, and vimentin, but not CD45.

CONCLUSIONS

This study establishes a potential method for isolation of hAMSCs from human amnion,in vitro culture, and identification. The isolated cells show phenotypic characteristics of mesenchymal stem cells.

Analysis of CD14 expression levels in putative mesenchymal progenitor cells isolated from equine bone marrow

A long-term goal of mesenchymal progenitor cell (MPC) research is to identify cell-surface markers to facilitate MPC isolation. One reported MPC feature in humans and other species is lack of CD14 (lipopolysaccharide receptor) expression. The aim of this study was to evaluate CD14 as an MPC sorting marker. Our hypothesis was that cells negatively selected by CD14 expression would enrich MPC colony formation compared with unsorted and CD14-positive fractions. After validation of reagents, bone marrow aspirate was obtained from 12 horses. Fresh and cultured cells were analyzed by flow cytometry and reverse transcription and quantitative polymerase chain reaction to assess dynamic changes in phenotype. In fresh samples, cells did not consistently express protein markers used for lineage classification. Short-term (2-day) culture allowed distinction between hematopoietic and nonhematopoietic populations. Magnetic activated cell sorting was performed on cells from 6 horses to separate adherent CD14(+) from CD14(-) cells. MPC colony formation was assessed at 7 days. Cells positively selected for CD14 expression were significantly more likely to form MPC colonies than both unsorted and negatively selected cells (P ≤ 0.005). MPCs from all fractions maintained low levels of CD14 expression long term, and upregulated CD14 gene and protein expression when stimulated with lipopolysaccharide. The equine CD14 molecule was trypsin-labile, offering a plausible explanation for the discrepancy with MPC phenotypes reported in other species. By definition, MPCs are considered nonhematopoietic because they lack expression of molecules such as CD14. Our results challenge this assumption, as equine MPCs appear to represent a descendant of a CD14-positive cell.

Temporal analysis of equine bone marrow aspirate during establishment of putative mesenchymal progenitor cell populations

Mesenchymal progenitor cells (MPCs) are often characterized using surface markers after expansion and treatment in culture. There are no studies directly comparing gene and protein markers in undifferentiated samples during the very early phases of culture. The goal of this study was to evaluate temporal gene and protein expression changes during establishment of equine MPC cultures. Bone marrow aspirate was obtained from 35 horses and processed by density gradient centrifugation. In freshly isolated bone marrow, mononuclear cells had variable expression of CD44, CD11a/CD18, CD90, and CD45RB cell surface molecules. After 2 h of culture, bone marrow mononuclear cells had a phenotype of CD44(hi), CD29(hi), CD90(lo), CD11a/CD18(hi), and CD45RB(lo). Isolated mononuclear cells were analyzed by flow cytometry and RT-qPCR at 2, 7, 14, 21, and 30 days of culture. At all culture time points, gene expression was in agreement with cell surface protein expression. In established cultures of MPCs, cells remained robustly positive for CD44 and CD29. The proportion of positive cells and the mean fluorescence intensity of positive cells increased in CD90 expression as MPC cultures became more homogeneous. Inversely, the population of cells in culture decreased expression of CD11a/CD18 and CD45RB molecules over time. The decreased expression of the latter molecules makes these useful negative markers of established MPC cultures under normal expansion conditions. The results of this study demonstrate numerous dynamic changes in cell surface molecule expression during early establishment of MPC populations, which may aid to improve MPC isolation methods for research or therapeutic applications.

New target cells of the immunomodulatory effects of progesterone

It is well known that the reproductive steroid hormones, particularly progesterone, in addition to its widely recognized effects on endometrial epithelial and stromal cells and spiral arteries, affect the activities of T cells and natural killer cells in the deciduas, thus inducing active immune tolerance against the fetal antigens. The immunomodulatory effects of progesterone on T cells, B cells and natural killer cells have been discussed extensively in the literature. The aim of the present review is to sum up and discuss the results from this and other laboratories of investigations on the effects of progesterone on dendritic cells and adult stem cells, which are some of the other cell populations present at the fetal-maternal interface and possibly are related to the immunoregulation during pregnancy. These cells have been shown to have a number of specific functions but their involvement in the entire process of regulation of the immune response in pregnancy is still under discussion. The present review focuses on facts showing that the progesterone is a kind of 'regulator of regulators' in the decidua, thus creating the most favourable conditions for the development of the semi-allogeneic fetus in successful pregnancy.

Differentiation of smooth muscle cells from human amniotic mesenchymal cells implanted in the freeze-injured mouse urinary bladder

BACKGROUND

The multipotency of human amniotic mesenchymal cells (HAMCs) has been reported, but the role of HAMCs in urinary tract regeneration is unknown.

OBJECTIVE

The aim of the study was to determine if cells derived from HAMCs support the structural and functional reconstruction of freeze-injured mouse bladders.

DESIGN, SETTING, AND PARTICIPANTS

HAMCs were harvested from an amnion membrane, and cells were cultured for 7 d prior to injection into the freeze-injured bladder walls of nude mice.

INTERVENTION

Three days prior to implantation, the posterior bladder walls were freeze injured for 30s. The cultured HAMC-derived cells (0.5 x 10(5) cells per 50 microl) were implanted into the injured regions. Control bladders received a cell-free injection. At 1, 2, 4, and 6 wk after the cell implantation, the experimental bladders were extirpated.

MEASUREMENTS

The bladder tissues were examined by immunohistochemistry for alpha-smooth muscle actin (SMA). The HAMC-derived cells were detected by antihuman nuclei antibody (HuNu). Separately, bladder muscle strips were examined for contractile responses to potassium.

RESULTS AND LIMITATIONS

At 1 wk after implantation, the HAMC-derived cells, which were detected by HuNu, differentiated into muscular layers composed of SMA-positive cells. From 2 to 6 wk after implantation, abundant layers of SMA-positive and HuNu-positive cells developed. In control bladders, few SMA-positive cells remained at the injured regions at 1 wk, but by 6 wk, more were present. At 1 wk, the contractile responses to potassium of the cell-implanted bladders were significantly higher than those of the control-injected ones. Control-injected bladders also recovered by 6 wk, but the rate of recovery was slower.

CONCLUSIONS

Freeze-injured mouse bladders implanted with HAMC-derived cells recovered morphology and function faster than control-injected bladders.

Transduction of the MPG-tagged fusion protein into mammalian cells and oocytes depends on amiloride-sensitive endocytic pathway

BACKGROUND

MPG is a cell-permeable peptide with proven efficiency to deliver macromolecular cargoes into cells. In this work, we examined the efficacy of MPG as an N-terminal tag in a fusion protein to deliver a protein cargo and its mechanism of transduction.

RESULTS

We examined transduction of MPG-EGFP fusion protein by live imaging, flow cytometry, along with combination of cell biological and pharmacological methods. We show that MPG-EGFP fusion proteins efficiently enter various mammalian cells within a few minutes and are co-localized with FM4-64, a general marker of endosomes. The transduction of MPG-EGFP occurs rapidly and is inhibited at a low temperature. The entry of MPG-EGFP is inhibited by amiloride, but cytochalasin D and methyl-beta-cyclodextrin did not inhibit the entry, suggesting that macropinocytosis is not involved in the transduction. Overexpression of a mutant form of dynamin partially reduced the transduction of MPG-EGFP. The partial blockade of MPG-EGFP transduction by a dynamin mutant is abolished by the treatment of amiloride. MPG-EGFP transduction is also observed in the mammalian oocytes.

CONCLUSION

The results show that the transduction of MPG fusion protein utilizes endocytic pathway(s) which is amiloride-sensitive and partially dynamin-dependent. Collectively, the MPG fusion protein could be further developed as a novel tool of "protein therapeutics", with potentials to be used in various cell systems including mammalian oocytes.