Concise Review: Multifaceted Characterization of Human Mesenchymal Stem Cells for Use in Regenerative Medicine

Mesenchymal stem cells derived from human iPS cells via mesoderm and neuroepithelium have different features and therapeutic potentials

Mesenchymal stem cells (MSCs) isolated from adult human tissues are capable of proliferating in vitro and maintaining their multipotency, making them attractive cell sources for regenerative medicine. However, the availability and capability of self-renewal under current preparation regimes are limited. Induced pluripotent stem cells (iPSCs) now offer an alternative, similar cell source to MSCs. Herein, we established new methods for differentiating hiPSCs into MSCs via mesoderm-like and neuroepithelium-like cells. Both derived MSC populations exhibited self-renewal and multipotency, as well as therapeutic potential in mouse models of skin wounds, pressure ulcers, and osteoarthritis. Interestingly, the therapeutic effects differ between the two types of MSCs in the disease models, suggesting that the therapeutic effect depends on the cell origin. Our results provide valuable basic insights for the clinical application of such cells.

Nanoscaled and microscaled parallel topography promotes tenogenic differentiation of ASC and neotendon formation in vitro

Background

Topography at different scales plays an important role in directing mesenchymal stem cell differentiation including adipose-derived stem cells (ASCs) and the differential effect remains to be investigated.

Purpose

This study aimed to investigate the similarity and difference between micro- and nanoscaled aligned topography for inducing tenogenic differentiation of human ASCs (hASCs).

Methods

Parallel microgrooved PDMS membrane and a parallel aligned electrospun nanofibers of gelatin/poly-ε-caprolactone mixture were employed as the models for the study.

Results

Aligned topographies of both microscales and nanoscales could induce an elongated cell shape with parallel alignment, as supported by quantitative cell morphology analysis (cell area, cell body aspect, and cell body major axis angle). qPCR analysis also demonstrated that the aligned topography at both scales could induce the gene expressions of various tenogenic markers at the 7th day of in vitro culture including tenomodulin, collagen I and collagen VI, decorin, tenascin-C and biglycan, but with upregulated expression of scleraxis and tenascin-C only in microscaled topography. Additionally, tenogenic differentiation at the 3rd day was confirmed only at microscale. Furthermore, microscaled topography was confirmed for its tenogenic induction at tissue level as neotendon tissue was formed with the evidence of mature type I collagen fibers only in parallel aligned polyglycolic acid (PGA) microfibers after in vitro culture with mouse ASCs. Instead, only fat tissue was formed in random patterned PGA microfibers.

Conclusion

Both microscaled and nanoscaled aligned topographies could induce tenogenic differentiation of hASCs and micro-scaled topography seemed better able to induce elongated cell shape and stable tenogenic marker expression when compared to nanoscaled topography. The microscaled inductive effect was also confirmed at tissue level by neotendon formation in vitro.

Extracellular vesicles: mediators and biomarkers of pathology along CNS barriers

Extracellular vesicles (EVs) are heterogeneous, nano-sized vesicles that are shed into the blood and other body fluids, which disperse a variety of bioactive molecules (e.g., protein, mRNA, miRNA, DNA and lipids) to cellular targets over long and short distances. EVs are thought to be produced by nearly every cell type, however this review will focus specifically on EVs that originate from cells at the interface of CNS barriers. Highlighted topics include, EV biogenesis, the production of EVs in response to neuroinflammation, role in intercellular communication and their utility as a therapeutic platform. In this review, novel concepts regarding the use of EVs as biomarkers for BBB status and as facilitators for immune neuroinvasion are also discussed. Future directions and prospective are covered along with important unanswered questions in the field of CNS endothelial EV biology.

In Vitro Neural Differentiation of Bone Marrow Mesenchymal Stem Cells Carrying the FTH1 Reporter Gene and Detection with MRI

Magnetic resonance imaging (MRI) based on the ferritin heavy chain 1 (FTH1) reporter gene has been used to trace stem cells. However, whether FTH1 expression is affected by stem cell differentiation or whether cell differentiation is affected by reporter gene expression remains unclear. Here, we explore the relationship between FTH1 expression and neural differentiation in the differentiation of mesenchymal stem cells (MSCs) carrying FTH1 into neuron-like cells and investigate the feasibility of using FTH1 as an MRI reporter gene to detect neurally differentiated cells. By inducing cell differentiation with all-trans retinoic acid and a modified neuronal medium, MSCs and MSCs-FTH1 were successfully differentiated into neuron-like cells (Neurons and Neurons-FTH1), and the neural differentiation rates were (91.56±7.89)% and (92.23±7.64)%, respectively. Neuron-specific markers, including nestin, neuron-specific enolase, and microtubule-associated protein-2, were significantly expressed in Neurons-FTH1 and Neurons without noticeable differences. On the other hand, FTH1 was significantly expressed in MSCs-FTH1 and Neurons-FTH1 cells, and the expression levels were not significantly different. The R2 value was significantly increased in MSCs-FTH1 and Neurons-FTH1 cells, which was consistent with the findings of Prussian blue staining, transmission electron microscopy, and intracellular iron measurements. These results suggest that FTH1 gene expression did not affect MSC differentiation into neurons and was not affected by neural differentiation. Thus, MRI reporter gene imaging based on FTH1 can be used for the detection of neurally differentiated cells from MSCs.

Evaluation of amnion-derived mesenchymal stem cells for treatment-resistant moderate Crohn's disease: study protocol for a phase I/II, dual-centre, open-label, uncontrolled, dose-response trial

Introduction

The medical treatment options for patients with Crohn’s disease (CD) are limited and patients resistant to those therapies are left requiring surgical operations that usually only achieve some symptomatic relief. Mesenchymal stem cells (MSC) have been shown to be effective for the treatment of CD, and we have demonstrated in animal experiments that human amnion-derived MSCs (AMSC) are a potential new therapeutic strategy. Therefore, we designed this study to investigate the safety and efficacy of AMSCs in patients with treatment-resistant CD.

Methods and analysis

This is the protocol for an ongoing phase I/II, dual-centre, open-label, uncontrolled, dose–response study. The estimated enrolment is 6–12 patients with treatment-resistant, moderate CD. A dose of 1.0×10⁶ cells/kg will be administered intravenously in the low-dose group at days 0 and 7. After confirming the safety of low-dose administration, a dose of 4.0×10⁶ cells/kg will be administered intravenously in the high-dose group on days 0 and 7. The primary endpoint will measure the occurrence of adverse events related to acute infusion toxicity, and secondary endpoints will include long-term adverse events and efficacy of AMSC administration.

Ethics and dissemination

The Institutional Review Board of Hokkaido University Hospital approved this study protocol (approval number H29-6). A report releasing study results will be submitted to an appropriate journal.

Discussion

This study is the first to investigate the safety and efficacy of AMSC use for CD treatment. Our results will advance studies on more efficient and convenient methods to overcome the limits of available CD treatments.

Trial registration number

UMIN000029841.

Modulation of autophagy as new approach in mesenchymal stem cell-based therapy

Due to their trophic and immunoregulatory characteristics mesenchymal stem cells (MSCs) have tremendous potential for use in a variety of clinical applications. Challenges in MSCs' clinical applications include low survival of transplanted cells and low grafting efficiency requiring use of a high number of MSCs to achieve therapeutic benefits. Accordingly, new approaches are urgently needed in order to overcome these limitations. Recent evidence indicates that modulation of autophagy in MSCs prior to their transplantation enhances survival and viability of engrafted MSCs and promotes their pro-angiogenic and immunomodulatory characteristics. Here, we review the current literature describing mechanisms by which modulation of autophagy strengthens pro-angiogenic and immunosuppressive characteristics of MSCs in animal models of multiple sclerosis, osteoporosis, diabetic limb ischemia, myocardial infarction, acute graft-versus-host disease, kidney and liver diseases. Obtained results suggest that modulation of autophagy in MSCs may represent a new therapeutic approach that could enhance efficacy of MSCs in the treatment of ischemic and autoimmune diseases.

Nanocomposites Based on Biodegradable Polymers

In the present review paper, our main results on nanocomposites based on biodegradable polymers (on a time scale from 2010 to 2018) are reported. We mainly focused our attention on commercial biodegradable polymers, which we mixed with different nanofillers and/or additives with the final aim of developing new materials with tunable specific properties. A wide list of nanofillers have been considered according to their shape, properties, and functionalization routes, and the results have been discussed looking at their roles on the basis of different adopted processing routes (solvent-based or melt-mixing processes). Two main application fields of nanocomposite based on biodegradable polymers have been considered: the specific interaction with stem cells in the regenerative medicine applications or as antimicrobial materials and the active role of selected nanofillers in food packaging applications have been critically revised, with the main aim of providing an overview of the authors' contribution to the state of the art in the field of biodegradable polymeric nanocomposites.

Osteogenic Differentiation Modulates the Cytokine, Chemokine, and Growth Factor Profile of ASCs and SHED

Great efforts have been made to improve bone regeneration techniques owing to a growing variety of sources of stem cells suitable for autologous transplants. Specifically, adipose-derived stem cells (ASCs) and stems cells from human exfoliated deciduous teeth (SHED) hold great potential for bone tissue engineering and cell therapy. After a preliminary characterization of the main biomolecules ASCs and SHED released in their conditioned media, cells were kept both in normal and osteo-inducing conditions. Conventional assays were performed to prove their osteogenic potential such as quantitative real-time polymerase chain reaction (qRT-PCR) (for RUNX-2, collagen type I, osteopontin and osteonectin), alkaline phosphatase activity, osteocalcin production, and von Kossa staining. Conditioned media were tested again after the osteogenic induction and compared to maintaining condition both at base line and after 14 days of culture. The osteogenic condition inhibited the release of all the biomolecules, with the exception, concerning SHED, of growth-regulated alpha protein precursor (GROα), and, to a lesser extent, interleukin (IL)-8. In conclusion, our data support that undifferentiated ASCs and SHED may be preferable to committed ones for general cell therapy approaches, due to their higher paracrine activity. Osteoinduction significantly affects the cytokine, chemokine, and growth factor profile in a differential way, as SHED kept a more pronounced pro-angiogenic signature than ASCs.

Intraoperative Construct Preparation: A Practical Route for Cell-Based Bone Regeneration

Stem cell-based bone tissue engineering based on the combination of a scaffold and expanded autologous mesenchymal stem cells (MSCs) represents the current state-of-the-art treatment for bone defects and fractures. However, the procedure of such construct preparation requires extensive ex vivo manipulation of patient's cells to achieve enough stem cells. Therefore, it is impractical and not cost-effective compared to other therapeutic interventions. For these reasons, a more practical strategy circumventing any ex vivo manipulation and an additional surgery for the patient would be advantageous. Intraoperative concept-based bone tissue engineering, where constructs are prepared with easily accessible autologous cells within the same surgical procedure, allows for such a simplification. In this study, we discuss the concept of intraoperative construct preparation for bone tissue engineering and summarize the available cellular options for intraoperative preparation. Furthermore, we propose methods to prepare intraoperative constructs, and review data of currently available preclinical and clinical studies using intraoperatively prepared constructs for bone regenerative applications. We identify several obstacles hampering the application of this emerging approach and highlight perspectives of technological innovations to advance the future developments of intraoperative construct preparation.

Mesenchymal stromal cells: a novel therapy for the treatment of chronic obstructive pulmonary disease?

COPD is characterised by tissue destruction and inflammation. Given the lack of curative treatments and the progressive nature of the disease, new treatments for COPD are highly relevant. In vitro cell culture and animal studies have demonstrated that mesenchymal stromal cells (MSCs) have the capacity to modify immune responses and to enhance tissue repair. These properties of MSCs provided a rationale to investigate their potential for treatment of a variety of diseases, including COPD. Preclinical models support the hypothesis that MSCs may have clinical efficacy in COPD. However, although clinical trials have demonstrated the safety of MSC treatment, thus far they have not provided evidence for MSC efficacy in the treatment of COPD. In this review, we discuss the rationale for MSC-based cell therapy in COPD, the main findings from in vitro and in vivo preclinical COPD model studies, clinical trials in patients with COPD and directions for further research.

Mesenchymal Stromal Cells: From Discovery to Manufacturing and Commercialization

Over the last decades, mesenchymal stromal cells (MSC) have been the focus of intense research by academia and industry due to their unique features. MSC can be easily isolated and expanded through in vitro culture by taking full advantage of their self-renewing capacity. In addition, MSC exert immunomodulatory effects and can be differentiated into various lineages, which makes them highly attractive for clinical applications in cell-based therapies. In this review, we attempt to provide a brief historical overview of MSC discovery, characterization, and the first clinical studies conducted. The current MSC manufacturing platforms are reviewed with special attention regarding the use of bioreactors for the production of GMP-compliant clinically relevant cell numbers. The first commercial MSC-based products are also addressed, as well as the remaining challenges to the widespread use of MSC-derived products.

How to Hit Mesenchymal Stromal Cells and Make the Tumor Microenvironment Immunostimulant Rather Than Immunosuppressive

Experimental evidence indicates that mesenchymal stromal cells (MSCs) may regulate tumor microenvironment (TME). It is conceivable that the interaction with MSC can influence neoplastic cell functional behavior, remodeling TME and generating a tumor cell niche that supports tissue neovascularization, tumor invasion and metastasization. In addition, MSC can release transforming growth factor-beta that is involved in the epithelial-mesenchymal transition of carcinoma cells; this transition is essential to give rise to aggressive tumor cells and favor cancer progression. Also, MSC can both affect the anti-tumor immune response and limit drug availability surrounding tumor cells, thus creating a sort of barrier. This mechanism, in principle, should limit tumor expansion but, on the contrary, often leads to the impairment of the immune system-mediated recognition of tumor cells. Furthermore, the cross-talk between MSC and anti-tumor lymphocytes of the innate and adaptive arms of the immune system strongly drives TME to become immunosuppressive. Indeed, MSC can trigger the generation of several types of regulatory cells which block immune response and eventually impair the elimination of tumor cells. Based on these considerations, it should be possible to favor the anti-tumor immune response acting on TME. First, we will review the molecular mechanisms involved in MSC-mediated regulation of immune response. Second, we will focus on the experimental data supporting that it is possible to convert TME from immunosuppressive to immunostimulant, specifically targeting MSC.

Mesenchymal Stem Cells and Calcium Phosphate Bioceramics: Implications in Periodontal Bone Regeneration

In orthopedic medicine, a feasible reconstruction of bone structures remains one of the main challenges both for healthcare and for improvement of patients' quality of life. There is a growing interest in mesenchymal stem cells (MSCs) medical application, due to their multilineage differentiation potential, and tissue engineering integration to improve bone repair and regeneration. In this review we will describe the main characteristics of MSCs, such as osteogenesis, immunomodulation and antibacterial properties, key parameters to consider during bone repair strategies. Moreover, we describe the properties of calcium phosphate (CaP) bioceramics, which demonstrate to be useful tools in combination with MSCs, due to their biocompatibility, osseointegration and osteoconduction for bone repair and regeneration. Also, we overview the main characteristics of dental cavity MSCs, which are promising candidates, in combination with CaP bioceramics, for bone regeneration and tissue engineering. The understanding of MSCs biology and their interaction with CaP bioceramics and other biomaterials is critical for orthopedic surgical bone replacement, reconstruction and regeneration, which is an integrative and dynamic medical, scientific and bioengineering field of research and biotechnology.

The Muse Cell Discovery, Thanks to Wine and Science

Multilineage-differentiating stress-enduring (Muse) cells, identified as cells positive for the pluripotent marker stage-specific embryonic antigen (SSEA-3+), were discovered as stress-tolerant pluripotent stem cells from among mesenchymal stem cells (MSCs) and fibroblasts, as well as from the adult human bone marrow mononucleated fraction. MSCs are a crude population of cells that differentiate into multiple cell types covering all three germ layers in low proportion and were thus deduced to contain a genuine pluripotent stem cell subpopulation. Muse cells constitute several percent of MSCs and 1 of ~3000 bone marrow mononucleated cells. They exhibit pluripotent gene expression as well as trilineage differentiation and self-renewal capabilities at the single-cell level, while, in contrast, MSC cells other than Muse cells do not exhibit these characteristics. These characteristics indicate that Muse cells correspond to the subpopulation of MSC cells responsible for the pluripotent aspect of MSCs. In addition to their pluripotency, Muse cells play an important role in vivo as endogenous stem cells that contribute to tissue homeostasis through daily reparative maintenance and to tissue reconstruction through their unique reparative functions following serious tissue damage. This chapter describes how my research team discovered Muse cells.

Melatonin alleviates oxidative stress-inhibited osteogenesis of human bone marrow-derived mesenchymal stem cells through AMPK activation

Oxidative stress plays an important role in the pathogenesis of aging-related osteoporosis through the increased bone resorption or reduced bone formation. Melatonin, which can exert beneficial actions through antioxidant, anti-inflammatory, and bone-preserving effects, shows promise in preventing oxidative stress-inhibited osteogenesis. However, specific mechanisms by which melatonin rescues oxidative stress-inhibited osteogenesis of human mesenchymal stem cells (MSCs) have not been fully elucidated yet. We therefore investigated whether activation of AMPK by melatonin regulates the antagonistic crosstalk between oxidative stress and osteogenic differentiation in human MSCs. Melatonin treatment significantly enhanced osteogenic differentiation of human MSCs through activation of AMPK and upregulation of FOXO3a and RUNX2 which were known as master transcription factors responsible for the mechanistic link between oxidative stress and osteogenic phenotype. Osteogenic differentiation determined by calcium deposition was significantly increased by melatonin treatment against oxidative stress. In addition, melatonin treatment reconstituted activation of AMPK and expression of FOXO3a and RUNX2 inhibited by oxidative stress. Overall, these results demonstrate that melatonin enhances osteogenic differentiation of human MSCs and restores oxidative stress-inhibited osteogenesis through AMPK activation in human MSCs, suggesting that activation of AMPK by melatonin may represent a promising new therapeutic strategy for treating metabolic bone diseases such as osteoporosis.

Comparison of Oxidative Stress Effects on Senescence Patterning of Human Adult and Perinatal Tissue-Derived Stem Cells in Short and Long-term Cultures

Human Mesenchymal Stem Cells (hMSCs) undergo senescence in lifespan. In most clinical trials, hMSCs experience long-term expansion ex vivo to increase cell number prior to transplantation, which unfortunately leads to cell senescence, hampering post-transplant outcomes. Hydrogen peroxide (H₂O₂) in vitro represents a rapid, time and cost-effective tool, commonly used as oxidative stress tantalizing the stem cell ability to cope with a hostile environment, recapitulating the onset and progression of cellular senescence. Here, H₂O₂ at different concentrations (ranging from 50 to 400 μM) and time exposures (1 or 2 hours - h), was used for the first time to compare the behavior of human Adipose tissue-derived Stem Cells (hASCs) and human Wharton's Jelly-derived MSCs (hWJ-MSCs), as representative of adult and perinatal tissue-derived stem cells, respectively. We showed timely different responses of hASCs and hWJ-MSCs at low and high subculture passages, concerning the cell proliferation, the cell senescence-associated β-Galactosidase activity, the capability of these cells to undergo passages, the morphological changes and the gene expression of tumor protein p53 (TP53, alias p53) and cyclin dependent kinase inhibitor 1A (CDKN1A, alias p21) post H₂O₂ treatments. The comparison between the hASC and hWJ-MSC response to oxidative stress induced by H₂O₂ is a useful tool to assess the biological mechanisms at the basis of hMSC senescence, but it could also provide two models amenable to test in vitro putative anti-senescence modulators and develop anti-senescence strategies.