Multipotent Mesenchymal Stem Cells Research Articles

Evidence for Aryl hydrocarbon Receptor-Mediated Inhibition of Osteoblast Differentiation in Human Mesenchymal Stem Cells.

Multipotent mesenchymal stem cells (MSCs) maintain the ability to differentiate into adipogenic, chondrogenic, or osteogenic cell lineages. There is increasing concern that exposure to environmental agents such as aryl hydrocarbon receptor (AhR) ligands, may perturb the osteogenic pathways responsible for normal bone formation. The objective of the current study was to evaluate the potential of the prototypic AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to disrupt osteogenic differentiation of human bone-derived MSCs (hBMSCs) in vitro. Primary hBMSCs from three donors were exposed to 10 nM TCDD and differentiation was interrogated using select histological, biochemical, and transcriptional markers of osteogenesis. Exposure to 10 nM TCDD resulted in an overall consistent attenuation of alkaline phosphatase (ALP) activity and matrix mineralization at terminal stages of differentiation in primary hBMSCs. At the transcriptional level, the transcriptional regulator DLX5 and additional osteogenic markers (ALP, OPN, and IBSP) displayed attenuated expression; conversely, FGF9 and FGF18 were consistently upregulated in each donor. Expression of stem cell potency markers SOX2, NANOG, and SALL4 decreased in the osteogenic controls, whereas expression in TCDD-treated cells resembled that of undifferentiated cells. Coexposure with the AhR antagonist GNF351 blocked TCDD-mediated attenuation of matrix mineralization, and either fully or partially rescued expression of genes associated with osteogenic regulation, extracellular matrix, and/or maintenance of multipotency. Thus, experimental evidence from this study suggests that AhR transactivation likely attenuates osteoblast differentiation in multipotent hBMSCs. This study also underscores the use of primary human MSCs to evaluate osteoinductive or osteotoxic potential of chemical and pharmacologic agents in vitro.

Immunosuppression of Human Adipose-Derived Stem Cells on T Cell Subsets via the Reduction of NF-kappaB Activation Mediated by PD-L1/PD-1 and Gal-9/TIM-3 Pathways.

Adipose-derived stem cells (ADSCs) are a type of multipotent mesenchymal stem cells with immunosuppressive capacities. However, the underlying mechanisms involved in the inhibitory effects of ADSCs on T cells are not completely elucidated. In this study, human peripheral blood mononuclear cells (PBMCs) stimulated with anti-CD3/CD28 antibody-coated beads were cultured with or without allogeneic ADSCs (ADSC-to-PBMC ratio, 1:5). Surface marker levels, violet-labeled cell proliferation, apoptosis, interferon-gamma (IFN-gamma) production, and nuclear factor-kappaB (NF-kappaB) phosphorylation of CD4+ and CD8+ T cells were detected using flow cytometry. It was observed that ADSCs significantly suppressed the proliferation and IFN-gamma production but enhanced apoptosis of both CD4+ and CD8+ T cells in T cell receptor (TCR)-stimulated PBMCs. The expressions of programmed death-ligand 1 (PD-L1) and galectin 9 (Gal-9) on ADSCs were significantly upregulated and induced during coculture with PBMCs. TCR-stimulated CD4+ and CD8+ T cells cultured with ADSCs had higher expression levels of programmed death-1 (PD-1) and T cell immunoglobulin and mucin-containing protein-3 (TIM-3) than those in cells cultured without ADSCs. Moreover, the suppressive effects of ADSCs on T cells in terms of proliferation and IFN-gamma production were significantly reversed in the presence of anti-PD-L1 and anti-Gal-9 antibodies. Importantly, the phosphorylation of NF-kappaB in CD4+ and CD8+ T cells cocultured with ADSCs was significantly inhibited, and this inhibition was significantly attenuated via the PD-L1 and Gal-9 blockades. In conclusion, human ADSCs perform immunoregulatory functions partially through the inhibition of NF-kappaB activation in T cells via the PD-L1/PD-1 and Gal-9/TIM-3 pathways, which provide new insights into the mechanism of human ADSC-mediated immunomodulation.

Comparative Analysis of Human Adipose-Derived Mesenchymal Stem Cells from Orbital and Abdominal Fat.

Adipose tissue contains abundant multipotent mesenchymal stem cells with strong proliferative and differentiating potential into adipocytes, osteocytes, and chondrocytes. However, adipose-derived mesenchymal stem cells (ASCs) showed variable characteristics based on the tissue-harvesting site. This study aimed at comparing human adipose-derived mesenchymal stem cell from the orbit (Orbital ASCs) and abdomen (Abdominal ASCs). Orbital and abdominal ASCs were isolated during an upper or lower blepharoplasty operation and liposuction, respectively. Flow cytometric analysis was done to analyze the surface antigens of ASCs, and cytokine profiles were measured using Luminex assay kit. The multilineage potential of both ASCs was investigated using Oil Red O, alizarin red, and alcian staining. Reverse transcriptase polymerase chain reaction (RT-PCR) was performed to measure mRNA levels of genes involved in these trilineage differentiations. Our results showed that both types of ASCs expressed the cell surface markers which are commonly expressed stem cells; however, orbital-ASCs showed higher expressions of CD73, CD90, CD105, and CD146 than abdominal ASCs. Unlikely, orbital-ASC expressed CD31, CD45 and HLA-DR lesser than abdominal-ASCs. Orbital ASCs secreted higher concentrations of eotaxin, fractalkine, IP-10, GRO, MCP-1, IL-6, IL-8, and RANTES but lower MIP-1α, FGF-2, and VEGF concentrations than abdominal-ASCs. Our result showed that orbital ASCs have higher potential towards adipogenic and osteogenic differentiation but lower tendency to chondrogenesis when compared with abdominal ASCs. In conclusion, tissue-harvesting site is a strong determinant for characterization of adipose-derived mesenchymal stem cells. Understanding defining phenotypes of such cells is useful for making suitable choices in different regenerative clinical indications.

MSX2 Initiates and Accelerates Mesenchymal Stem/Stromal Cell Specification of hPSCs by Regulating TWIST1 and PRAME

SummaryThe gap in knowledge of the molecular mechanisms underlying differentiation of human pluripotent stem cells (hPSCs) into the mesenchymal cell lineages hinders the application of hPSCs for cell-based therapy. In this study, we identified a critical role of muscle segment homeobox 2 (MSX2) in initiating and accelerating the molecular program that leads to mesenchymal stem/stromal cell (MSC) differentiation from hPSCs. Genetic deletion of MSX2 impairs hPSC differentiation into MSCs. When aided with a cocktail of soluble molecules, MSX2 ectopic expression induces hPSCs to form nearly homogeneous and fully functional MSCs. Mechanistically, MSX2 induces hPSCs to form neural crest cells, an intermediate cell stage preceding MSCs, and further differentiation by regulating TWIST1 and PRAME. Furthermore, we found that MSX2 is also required for hPSC differentiation into MSCs through mesendoderm and trophoblast. Our findings provide novel mechanistic insights into lineage specification of hPSCs to MSCs and effective strategies for applications of stem cells for regenerative medicine.

Osteogenic differentiation of mesenchymal stem cells modulated by a chemically modified super-hydrophilic titanium implant surface.

This study investigated the osteogenic functionality of multipotent mesenchymal stem cells (MSCs) modulated by a chemically modified super-hydrophilic titanium (Ti) bone implant surface to elucidate the biological mechanism underlying the bone healing capacity of this modified Ti surface. A microstructured Ti surface incorporating bioactive ions (in this study, phosphate (P) ions) was prepared by wet chemical treatment. The results showed that the hydrothermally obtained crystalline P-incorporated Ti surface (P surface) displayed long-term super-hydrophilicity (water contact angles <5°) during a 36-week observation period. The hydrophilic P surface enhanced early cellular functions and osteogenic differentiation of multipotent MSCs derived from mouse bone marrow and human adipose tissue. The expression of critical integrins affecting subsequent osteoblast function and osteoblast phenotype genes was notably upregulated in multipotent MSCs grown on the P surface compared with the commercially available grit-blasted microrough clinical oral implant surface. The P surface supported better cell spreading, focal adhesion and ALP activity of MSCs. These results indicate that a super-hydrophilic P-incorporated Ti surface accelerates implant bone healing by enhancing the early osteogenesis functions of multipotent MSCs.

Abstract 4128: Loss of p53 and Rb enhances ligand-dependent hedgehog signaling in development and cancer

Abstract The evolutionary conserved Hedgehog (Hh) signaling pathway plays fundamental morphogenic and mitogenic roles in tissue development and homeostasis, as well as in the initiation and progression of various cancers. Signaling is driven by the binding of Sonic hedgehog (Shh) ligand to the receptor Patched (Ptch1), to initiate primary cilia dependent Smoothened (Smo)-Gli activation. Although mutations in Hh pathway components are described in some cancers, the majority of Hh tumors exhibit ligand-dependent Hh signaling, where Hh ligand is produced by the stroma and/or tumor cells to maintain pathway activation and self-renewal. Here, we have utilized various Hh-dependent developmental models to better understand the tumorigenic mechanisms of Hh ligand-dependent signaling in cancer. During cerebellar development, Shh is secreted from cerebellar purkinje cells for rapid expansion of the cerebellar granule cell precursor (GCP) population in the external granule layer (EGL). Inactivation of Shh in purkinje cells (Pcp2Cre;Shhfl/fl) leads to reduced GCP proliferation, premature eradication of the EGL and reduced cerebellar size. In contrast, Shh overexpression by purkinje cells (Pcp2Cre;ShhTg) results in increased GCP expansion, a sustained EGL and increased cerebellar size. Indeed, signs of remnant EGL persist into adulthood, similar to the pre-neoplastic lesions observed in Ptch1+/- mice, believed to be the origin of SHH medulloblastoma. During skeletal development, Indian hedgehog secreted from pre-hypertrophic chondroblasts is required for osteoblast progenitor specification from multipotent mesenchymal stem cells. Sustained Hh signaling in osteoblast precursors (OsxCre;SmoM2 or OsxCre;ShhTg) results in reduced ossification of the calvaria, maxilla and mandible, reduced long bone width, and reduced expression of mature osteoblast markers. Together, these models implicate sustained Hh expression in the maintenance of an immature cell state at the expense of differentiation. Moreover, in a mouse model of osteosarcoma, inactivation of Smo (OsxCre;p53fl/fl;Rbfl/fl;Smofl/fl) abolished the malignant phenotype of OsxCre;p53fl/fl;Rbfl/fl mice, leading to benign osteoid osteoma consistent with osteoblast differentiation. Increased Hh signaling in cancers with prevalent p53 and Rb mutations led us to investigate a role for p53 and Rb in Hh ligand-dependent signaling. Genetic inactivation of p53 and/or Rb in the developing mouse neural tube resulted in expansion of the Hh-dependent Nkx2.2 ventral domain, consistent with a Hh gain of function phenotype. Similarly, siRNA knockdown of p53 and/or Rb in mouse mesenchymal stem cell line C3H10T1/2 markedly increased Hh-dependent osteoblast specification in response to Hh ligand. Taken together, we propose that p53 and Rb mutations enhance ligand-dependent Hh pathway activation that maintains cells in a primitive state and promotes tumorigenesis. Citation Format: Catherine R. Cochrane, Anette Szczepny, Samantha W. Jayasekara, Vijesh Vaghjiani, D. Watkins, Jason E. Cain. Loss of p53 and Rb enhances ligand-dependent hedgehog signaling in development and cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4128.

Dental pulp stem cells and osteogenesis: an update.

Dental pulp stem cells constitute an attractive source of multipotent mesenchymal stem cells owing to their high proliferation rate and multilineage differentiation potential. Osteogenesis is initiated by osteoblasts, which originate from mesenchymal stem cells. These cells express specific surface antigens that disappear gradually during osteodifferentiation. In parallel, the appearance of characteristic markers, including alkaline phosphatase, collagen type I, osteocalcin and osteopontin characterize the osteoblastic phenotype of dental pulp stem cells. This review will shed the light on the osteogenic differentiation potential of dental pulp stem cells and explore the culture medium components, and markers associated with osteodifferentiation of these cells.

Thermoresponsive Citrate-Based Graphene Oxide Scaffold Enhances Bone Regeneration from BMP9-Stimulated Adipose-Derived Mesenchymal Stem Cells.

Effective bone tissue engineering is important to overcome the unmet clinical challenges as more than 1.6 million bone grafts are done annually in the United States. Successful bone tissue engineering needs minimally three critical constituents: osteoprogenitor cells, osteogenic factors, and osteoinductive/osteoconductive scaffolds. Osteogenic progenitors are derived from multipotent mesenchymal stem cells (MSCs), which can be prepared from numerous tissue sources, including adipose tissue. We previously showed that BMP9 is the most osteogenic BMP and induces robust bone formation of immortalized mouse adipose-derived MSCs entrapped in a citrate-based thermoresponsive hydrogel referred to as PPCNg. As graphene and its derivatives emerge as promising biomaterials, here we develop a novel thermosensitive and injectable hybrid material by combining graphene oxide (GO) with PPCNg (designated as GO-P) and characterize its ability to promote bone formation. We demonstrate that the thermoresponsive behavior of the hybrid material is maintained while effectively supporting MSC survival and proliferation. Furthermore, GO-P induces early bone-forming marker alkaline phosphatase (ALP) and potentiates BMP9-induced expression of osteogenic regulators and bone markers as well as angiogenic factor VEGF in MSCs. In vivo studies show BMP9-transduced MSCs entrapped in the GO-P scaffold form well-mineralized and highly vascularized trabecular bone. Thus, these results indicate that GO-P hybrid material may function as a new biocompatible, injectable scaffold with osteoinductive and osteoconductive activities for bone regeneration.

Multilineage potential research of Beijing duck amniotic mesenchymal stem cells

Amnion, which is usually discarded as medical waste, is considered as abundant sources for mesenchymal stem cells. In human and veterinary medicine, the multipotency of mesenchymal stem cells derived from amnion (AMSCs) together with their plasticity, self-renewal, low immunogenicity and nontumorigenicity characteristics make AMSCs a promising candidate cell for cell-based therapies and tissue engineering. However, up till now, the multipotential characteristics and therapeutic potential of AMSCs on preclinical studies remain uncertain. In this work, we successfully obtained AMSCs from Beijing duck embryos in vitro, and also attempted to detect their biological characteristics. The isolated AMSCs were phenotypically identified, the growth kinetics and karyotype were tested. Also, the cells were positive for MSCs-related markers (CD29, CD71, CD105, CD166, Vimentin and Fibronection), while the expression of CD34 and CD45 were undetectable. Additionally, AMSCs also expressed the pluripotent marker gene OCT4. Particularly, when appropriately induced, AMSCs could be induced to trans-differentiate into adipocytes, osteoblasts, chondrocytes and neurocytes in vitro. Together, these results demonstrated that the isolated AMSCs maintained their stemness and proliferation in vitro, which may be useful for future cell therapy in regenerative medicine.

Effects of Perinatal Exposure to Dibutyltin Chloride on Fat and Glucose Metabolism in Mice, and Molecular Mechanisms, in Vitro.

Background:The organotin dibutyltin (DBT) is used in the manufacture of polyvinyl chloride (PVC) plastics, in construction materials, and in medical devices. Previous animal studies showed detrimental effects of DBT during in utero development at relatively high doses, but little was known about the effects of DBT exposure at environmentally relevant doses on endpoints such as obesity and metabolic disease.Objectives:We tested the potential obesogenic effects of DBT using in vitro and in vivo models.Methods.We evaluated the effects of DBT on nuclear receptor activation and adipogenic potential using human and mouse multipotent mesenchymal stromal stem cells (MSCs). We also evaluated the effects of perinatal exposure to environmentally relevant doses of DBT in C57BL/6J mice.Results:DBT activated human and mouse and in transient transfection assays, increased expression of adipogenic genes, promoted adipogenic differentiation and increased lipid accumulation in mouse and human MSCs, in vitro. DBT-induced adipogenic differentiation was abolished by the antagonist T0070907, indicating that DBT was acting primarily through . Perinatal exposure to low doses of DBT led to increased fat storage, decreased glucose tolerance, and increased circulating leptin levels in male, but not female, mice.Conclusions:DBT acted as an obesogen by inducing lipid accumulation in human and mouse MSCs through a pathway. In vivo exposure to biologically relevant doses of DBT during perinatal development led to increased fat storage, elevated leptin levels in plasma, and glucose intolerance in mice. Based on these findings, we posit that monitoring of DBT levels in human samples may aid in understanding and potentially preventing the rising rates of metabolic disorders in human populations. https://doi.org/10.1289/EHP3030

Intracellular accumulation of gold nanoparticles by multipotent bone marrow-derived mesenchymal stem cells

Gold nanoparticles formed by mesenchymal stem cells have tremendous diagnostic and therapeutic potential in cancer. Bone marrow-derived mesenchymal stem cells (BM-MSCs) grown to ∼90% confluency exhibited intracellular gold nanoparticles (AuNPs) accumulation when incubated in 1 mM auric chloride in phosphate buffered saline (PBS) at pH 7.4 for 28 days. Scanning electron microscopy (SEM) and elemental mapping confirmed the growth and distribution of AuNPs within cells and on cell membranes, respectively. Transmission electron microscopy (TEM) of ultrathin-microtome sections of BM-MSCs incubated in auric chloride solution showed the accumulation of AuNPs throughout cells, especially on cell membranes, and within cytoplasm (especially vesicles) and nuclei. Raman spectroscopy showed the interaction of accumulated AuNPs with intracellular proteins, fatty acids, and nucleic acids, and results suggested that these AuNPs could, by enhancing Raman signals, be used to monitor cellular process. The results obtained demonstrated for the first time, the ability of BM-MSCs to bioreduce Au(III) and produce biocompatible AuNPs in cytoplasm and nuclei. This synthesis of gold nanoparticles in BM-MSCs, as intracellular accumulations, without using any added reducing or capping/stabilizing agent is potentially useful for several nano(bio)technological and biomedical applications.

Adipose tissue: A natural resource for multipotent mesenchymal stem cells with potential translation to trigerminal layers.

Background:The article reports basic science research that establishes that adipose tissue (AT)-derived mesenchymal stem cells (MSCs) have a potential to transgerminal translation.Study Design:MSC confirmation was obtained by phenotypic spindle-shaped cells as well as with four positive and three negative markers. The translineage translation of adipose-derived MSCs (ADMSCs) was established.Materials and Methods:The lipoaspirate was subjected to enzymatic digestion with collagenase. Stromal vascular factor (SVF) was isolated. With two passages, pure culture of ADMSCs was obtained. They were translated to all the three germinal layers.Results:AT-derived SVF contains ~30% MSCs. They are capable of being translated into endoderm, mesoderm and ectoderm.Conclusion:AT is a rich source for MSCs, with immense research possibilities for regeneration and rejuvenation.

Improvement of Cell Cycle Lifespan and Genetic Damage Susceptibility of Human Mesenchymal Stem Cells by Hypoxic Priming.

Hypoxic culture is widely recognized as a method to efficiently expand human mesenchymal stem cells (MSCs) without loss of stem cell properties. However, the molecular basis of how hypoxia priming benefits MSC expansion remains unclear. We report that hypoxic priming markedly extends the cell cycle lifespan rather than augmenting the multipotency of MSC differentiation lineage. Hypoxic priming does not affect to chromosome damage but significantly attenuates the susceptibility of chromosome damage. Our results provide important evidence that multipotency of human MSCs by hypoxic priming is determined by cell cycle lifespan.

Local Mesenchymal Stem Cell Therapy in Experimentally Induced Colitis in the Rat.

BackgroundMultipotent mesenchymal stem cells (MSCs) have been used in inflammatory bowel diseases because of their immunomodulatory and regenerative properties. We investigated their local use in an experimental model of colitis in the rat.Materials and MethodsColitis was induced into 20 Wistar rats with local TNBS instillation. Allogeneic stem cells were derived from rat adipose tissue and labeled with PKH2 linker dye with creation of a control and a second group treated by a local injection into the rectal wall of 2×106 allogeneic adipose tissue-derived stem cells (ADSCs). The thicknesses of different components of the rectum were measured with comparisons made in different parts of the colon of the Hunter inflammatory score. PKH2-dyed ADSCs were detected by fluorescence microscopy.Results and ConclusionsTotal colitis was induced in 19/20 rats with homing of fluorescent ADSCs. to the crypt base and perivascular space of the submucosa. There were no differences in component rectal wall thicknesses with a higher Hunter score in the treated group compared with the controls, in the rectum (3.8±2.74 vs. 1.5±2.37, respectively; p=0.017) and in right colon (2.5±1.08 vs. 0.20±0.42, respectively; p=0.0001). Local colonic injection of allogeneic adipose stem cells. in experimental colitis is feasible and safe. There is demonstrable homing of cells in chemically-induced colitis both to the treated region and parts of the colon distant to the MSC treatment site. Such cells readily proliferate in vitro and could potentially be a source for future treatment of resistant disease.

EXPERIMENTAL RESULTS OF RAT HYALINE CARTILAGE SURFACE DEFECT REPLACEMENT WITH A CELL ENGINEERING STRUCTURE

Nowadays, hyaline cartilage damage therapy and repair is one of the most topical research fields in regenerative medicine. however, in spite of a large number of methods used in clinical practice, this problem has not been fully solved yet. a promising approach in dealing with this problem may be a transplantation of a cell engineering structure (CES), made up of cell culture and biodegradable scaffold (membrane). In our experiments with animal models we used a membrane made of polylactide and multipotent mesenchymal stem cells (MSC) culture, and the damage of the knee joint hyaline layer was simulated by dental boron. The cell culture was pre-modified by TGF-β-3 growth factor to promote the synthesis of extracellular matrix proteins (ECM). as a result, we observed a fourfold increase in Acan and col2a1 expression compared to the control. Damaged areas were analyzed by scanning electron microscopy (SEM) over long observation periods (up to 90 days), and the diameter of the damaged area was found to decrease after CES transplantation, while the damage area in the control group, without CES, increased more than 2.5-fold in diameter. Thus, application of cell engineering structures is a promising method of repairing the damaged layer of hyaline cartilage. however, further studies are needed to enhance the effectiveness of the cell culture modification, develop methods for combining it with biodegradable scaffold, and select the method of fixing the CES in the damaged area.

Bone tissue engineering strategy based on the synergistic effects of silicon and strontium ions

Multipotent human bone marrow mesenchymal stem cells (hBMSCs) are commonly used as seed cells in bone tissue engineering, but their clinical application is limited due to two challenges. One is the expansion of hBMSCs without loss of the stemness, and the other is the stimulation of osteogenic differentiation of hBMSCs when combined with biomaterials. In this study we demonstrated an approach by firstly elucidating the functional effects and optimal concentrations of Si and Sr ions on the proliferation and osteogenic differentiation of hBMSCs, and then designing bioactive bioceramic/alginate hydrogels which could release Si and Sr bioactive ions in the same optimal concentrations range for activation of the cells in vivo. The results showed that Si and Sr ions could synergistically stimulate cell proliferation without losing the stemness. Furthermore, at higher concentrations, Si and Sr ions stimulated osteogenic differentiation instead of enhancing proliferation. The designed bioactive hydrogels revealed activity to stimulate not only the osteogenic differentiation of encapsulated hBMSCs, but also the blood vessel formation in vivo. These results suggested that the design of biomaterials based on the biological function of different material elements was an effective approach for bone tissue engineering applications. Statement of SignificanceThe clinical application of multipotent human bone marrow mesenchymal stem cells (hBMSCs) in bone tissue engineering is limited due to two challenges. One is the expansion of cells without loss of the stemness, and the other is the stimulation of osteogenic differentiation of hBMSCs within the biomaterial scaffolds. Herein, we demonstrated an approach by firstly elucidating the functional effects and optimal concentrations of Si and Sr ions on the proliferation without losing stemness and osteogenic differentiation of hBMSCs, and then designing a bioactive bioceramic/alginate hydrogel which could release Si and Sr ions for in vivo activation of cells. The bioactive hydrogels revealed activity to stimulate not only osteogenic differentiation of encapsulated hBMSCs, but also the blood vessel formation in vivo. Our work provided an effective approach to design effective biomaterials for tissue engineering.

The variable role of SIRT1 in the maintenance and differentiation of mesenchymal stem cells.

SIRT1 is an NAD+-dependent deacetylase that acts as a nutrient sensitive regulator of longevity. SIRT1 also acts as a key regulator of mesenchymal stem cells (MSCs),adult stem cells that give rise to tissues such as bone, fat, muscle and cartilage. This review focuses on how SIRT1 regulates the self-renewal, multipotency and differentiation of MSCs. The variable role of SIRT1 in promoting the differentiation of MSCs towards certain lineages, while repressing others, will be examined within the broader context of aging,calorie restriction, and regenerative medicine. Finally, recent animal and human studies will be highlighted which paint an overall salutary role for SIRT1 in protecting MSCs (and resulting tissues) from age-related atrophy and dysfunction.

Miro1 Enhances Mitochondria Transfer from Multipotent Mesenchymal Stem Cells (MMSC) to Neural Cells and Improves the Efficacy of Cell Recovery.

A recently discovered key role of reactive oxygen species (ROS) in mitochondrial traffic has opened a wide alley for studying the interactions between cells, including stem cells. Since its discovery in 2006, intercellular mitochondria transport has been intensively studied in different cellular models as a basis for cell therapy, since the potential of replacing malfunctioning organelles appears to be very promising. In this study, we explored the transfer of mitochondria from multipotent mesenchymal stem cells (MMSC) to neural cells and analyzed its efficacy under normal conditions and upon induction of mitochondrial damage. We found that mitochondria were transferred from the MMSC to astrocytes in a more efficient manner when the astrocytes were exposed to ischemic damage associated with elevated ROS levels. Such transport of mitochondria restored the bioenergetics of the recipient cells and stimulated their proliferation. The introduction of MMSC with overexpressed Miro1 in animals that had undergone an experimental stroke led to significantly improved recovery of neurological functions. Our data suggest that mitochondrial impairment in differentiated cells can be compensated by receiving healthy mitochondria from MMSC. We demonstrate a key role of Miro1, which promotes the mitochondrial transfer from MMSC and suggest that the genetic modification of stem cells can improve the therapies for the injured brain.

Human Umbilical Cord Matrix Stem Cells Reverse Oxidative Stress-Induced Cell Death and Ameliorate Motor Function and Striatal Atrophy in Rat Model of Huntington Disease.

Huntington disease (HD) is an inherited disorder hallmarked by progressive deterioration of specific neurons, followed by movement and cognitive anomalies. Cell therapy approaches in neurodegenerative conditions have concentrated on the replenishment of lost/dying neurons with functional ones. Multipotent mesenchymal stem cells (MSCs) have been represented as a potential remedy for HD. In this study, we evaluated the in vitro and in vivo efficacy of umbilical cord matrix stem cells (UCMSCs) and their paracrine effect against oxidative stress with a specific focus on HD. To this end, UCMSCs were isolated, immunophenotypically characterized by the positive expression of MSC markers, and exhibited multilineage potentiality. Besides, synthesis of neurotrophic factors of GDNF and VEGF by UCMSC was confirmed. Initially, PC12 cells were exposed to superoxide in the presence of conditioned media (CM) collected from UCMSC (UCMSC-CM) and cell viability plus neuritogenesis were measured. Next, bilateral striatal transplantation of UCMSC in 3-nitropropionic acid (3-NP) lesioned rat models was conducted, and 1month later, post-graft analysis was performed. According to our in vitro results, CM of UCMSC protected PC12 cells against oxidative stress and considerably enhanced cell viability and neurite outgrowth. On the other hand, transplanted UCMSC survived, decreased gliosis, and ameliorated motor coordination and muscle activity, along with an increase in striatal volume as well as in dendritic length of the striatum in HD rats. Collectively, our findings imply that UCMSCs provide an enriched platform by largely their paracrine factors, which downgrades the unfavorable effects of oxidative stress.

Bone marrow mesenchymal stem cells as nuclear donors improve viability and health of cloned horses.

IntroductionCell plasticity is crucial in cloning to allow an efficient nuclear reprogramming and healthy offspring. Hence, cells with high plasticity, such as multipotent mesenchymal stem cells (MSCs), may be a promising alternative for horse cloning. In this study, we evaluated the use of bone marrow-MSCs (BM-MSCs) as nuclear donors in horse cloning, and we compared the in vitro and in vivo embryo development with respect to fibroblasts.Materials and methodsZona-free nuclear transfer was performed using BM-MSCs (MSC group, n=3432) or adult fibroblasts (AF group, n=4527). Embryos produced by artificial insemination (AI) recovered by uterine flushing and transferred to recipient mares were used as controls (AI group).ResultsBlastocyst development was higher in the MSC group than in the AF group (18.1% vs 10.9%, respectively; p<0.05). However, pregnancy rates and delivery rates were similar in both cloning groups, although they were lower than in the AI group (pregnancy rates: 17.7% [41/232] for MSC, 12.5% [37/297] for AF and 80.7% [71/88] for AI; delivery rates: 56.8% [21/37], 41.5% [17/41] and 90.1% [64/71], respectively). Remarkably, the gestation length of the AF group was significantly longer than the control (361.7±10.9 vs 333.9±8.7 days), in contrast to the MSC group (340.6±8.89 days). Of the total deliveries, 95.2% (20/21) of the MSC-foals were viable, compared to 52.9% (9/17) of the AF-foals (p<0.05). In addition, the AF-foals had more physiological abnormalities at birth than the MSC-foals; 90.5% (19/21) of the MSC-delivered foals were completely normal and healthy, compared to 35.3% (6/17) in the AF group. The abnormalities included flexural or angular limb deformities, umbilical cord enlargement, placental alterations and signs of syndrome of neonatal maladjustment, which were treated in most cases.ConclusionIn summary, we obtained 29 viable cloned foals and found that MSCs are suitable donor cells in horse cloning. Even more, these cells could be more efficiently reprogrammed compared to fibroblasts.