Human mesenchymal stem cells: from immunophenotyping by flow cytometry to clinical applications

Perspectives on Stem Cell Therapy in Diabetic Neuropathic Pain

Diabetes mellitus-related morbidity and mortality are primarily caused by long-term complications such as retinopathy, nephropathy, cardiomyopathy, and neuropathy. Diabetic neuropathy (DN) involves the progressive degeneration of axons and nerve fibers due to chronic exposure to hyperglycemia. This metabolic disturbance leads to excessive activation of the glycolytic pathway, inducing oxidative stress and mitochondrial dysfunction, ultimately resulting in nerve damage. There is no specific treatment for painful DN, and new approaches should aim not only to relieve pain but also to prevent oxidative stress and reduce inflammation. Given that existing therapies for painful DN are not effective for diabetic patients, mesenchymal stromal cells (MSCs)-based therapy shows promise for providing immunomodulatory and paracrine regulatory functions. MSCs from various sources can improve neuronal dysfunction associated with DN. Transplantation of MSCs has led to a reduction in hyperalgesia and allodynia, along with the recovery of nerve function in diabetic rats. While the pathogenesis of diabetic neuropathic pain is complex, clinical trials have demonstrated the importance of MSCs in modulating the immune response in diabetic patients. MSCs reduce the levels of inflammatory factors and increase anti-inflammatory cytokines, thereby interfering with the progression of DM. Further investigation is necessary to ensure the safety and efficacy of MSCs in preventing or treating neuropathic pain in diabetic patients.

Application of mesenchymal stem cells for anti-senescence and clinical challenges

Senescence is a hot topic nowadays, which shows the accumulation of senescent cells and inflammatory factors, leading to the occurrence of various senescence-related diseases. Although some methods have been identified to partly delay senescence, such as strengthening exercise, restricting diet, and some drugs, these only slow down the process of senescence and cannot fundamentally delay or even reverse senescence. Stem cell-based therapy is expected to be a potential effective way to alleviate or cure senescence-related disorders in the coming future. Mesenchymal stromal cells (MSCs) are the most widely used cell type in treating various diseases due to their potentials of self-replication and multidirectional differentiation, paracrine action, and immunoregulatory effects. Some biological characteristics of MSCs can be well targeted at the pathological features of aging. Therefore, MSC-based therapy is also a promising strategy to combat senescence-related diseases. Here we review the recent progresses of MSC-based therapies in the research of age-related diseases and the challenges in clinical application, proving further insight and reference for broad application prospects of MSCs in effectively combating senesce in the future.

Advances of mesenchymal stem cells and their derived extracellular vesicles as a promising therapy for acute respiratory distress syndrome: from bench to clinic

Acute respiratory distress syndrome (ARDS) is an acute inflammatory lung injury characterized by diffuse alveolar damage. The period prevalence of ARDS was 10.4% of ICU admissions in 50 countries. Although great progress has been made in supportive care, the hospital mortality rate of severe ARDS is still up to 46.1%. Moreover, up to now, there is no effective pharmacotherapy for ARDS and most clinical trials focusing on consistently effective drugs have met disappointing results. Mesenchymal stem cells (MSCs) and their derived extracellular vesicles (EVs) have spawned intense interest of a wide range of researchers and clinicians due to their robust anti-inflammatory, anti-apoptotic and tissue regeneration properties. A growing body of evidence from preclinical studies confirmed the promising therapeutic potential of MSCs and their EVs in the treatment of ARDS. Based on the inspiring experimental results, clinical trials have been designed to evaluate safety and efficacy of MSCs and their EVs in ARDS patients. Moreover, trials exploring their optimal time window and regimen of drug administration are ongoing. Therefore, this review aims to present an overview of the characteristics of mesenchymal stem cells and their derived EVs, therapeutic mechanisms for ARDS and research progress that has been made over the past 5 years.

Therapeutic Applications of Mesenchymal Stem Cell Loaded with Gold Nanoparticles for Regenerative Medicine

In the present study, the various concentrations of AuNP (1.25, 2.5, 5, 10 ppm) were prepared to investigate the biocompatibility, biological performances and cell uptake efficiency via Wharton's jelly mesenchymal stem cells and rat model. The pure AuNP, AuNP combined with Col (AuNP-Col) and FITC conjugated AuNP-Col (AuNP-Col-FITC) were characterized by Ultraviolet-visible spectroscopy (UV-Vis), Fourier-transform infrared spectroscopy (FTIR) and Dynamic Light Scattering (DLS) assays. For in vitro examinations, we explored whether the Wharton's jelly MSCs had better viability, higher CXCR4 expression, greater migration distance and lower apoptotic-related proteins expression with AuNP 1.25 and 2.5 ppm treatments. Furthermore, we considered whether the treatments of 1.25 and 2.5 ppm AuNP could induce the CXCR4 knocked down Wharton's jelly MSCs to express CXCR4 and reduce the expression level of apoptotic proteins. We also treated the Wharton's jelly MSCs with AuNP-Col to investigate the intracellular uptake mechanisms. The evidence demonstrated the cells uptake AuNP-Col through clathrin-mediated endocytosis and the vacuolar-type H+-ATPase pathway with good stability inside the cells to avoid lysosomal degradation as well as better uptake efficiency. Additionally, the results from in vivo examinations elucidated the 2.5 ppm of AuNP attenuated foreign body responses and had better retention efficacy with tissue integrity in animal model. In conclusion, the evidence demonstrates that AuNP shows promise as a biosafe nanodrug delivery system for development of regenerative medicine coupled with Wharton's jelly MSCs.

Human Fibroblast Growth Factor-Treated Adipose-Derived Stem Cells Facilitate Wound Healing and Revascularization in Rats with Streptozotocin-Induced Diabetes Mellitus

Diabetes mellitus contributes to 15-25% of all chronic foot ulcers. Peripheral vascular disease is a cause of ischemic ulcers and exacerbates diabetic foot disease. Cell-based therapies are viable options to restore damaged vessels and induce the formation of new vessels. Adipose-derived stem cells (ADSCs) have the potential for angiogenesis and regeneration because of their greater paracrine effect. Preclinical studies are currently using other forced enhancement techniques (e.g., genetic modification or biomaterials) to increase the efficacy of human ADSC (hADSC) autotransplantation. Unlike genetic modifications and biomaterials, many growth factors have been approved by the equivalent regulatory authorities. This study confirmed the effect of enhanced human ADSC (ehADSC)s with a cocktail of FGF and other pharmacological agents to promote wound healing in diabetic foot disease. In vitro, ehADSCs exhibited a long and slender spindle-shaped morphology and showed significantly increased proliferation. In addition, it was shown that ehADSCs have more functionalities in oxidative stress toleration, stem cell stemness, and mobility. In vivo, the local transplantation of 1.2 × 10⁶ hADSCs or ehADSCs was performed in animals with diabetes induced by STZ. The ehADSC group showed a statistically decreased wound size and increased blood flow compared with the hADSC group and the sham group. Human Nucleus Antigen (HNA) positive cells were observed in some ADSC-transplanted animals. The ehADSC group showed a relatively higher portion of HNA-positive animals than the hADSC group. The blood glucose levels showed no significant difference among the groups. In conclusion, the ehADSCs showed a better performance in vitro, compared with conventional hADSCs. Additionally, a topical injection of ehADSCs into diabetic wounds enhanced wound healing and blood flow, while improving histological markers suggesting revascularization.

VEGF Expression in Umbilical Cord MSC Depends on the Patient's Health, the Week of Pregnancy in Which the Delivery Took Place, and the Body Weight of the Newborn - Preliminary Report

Introduction

Cells collected from Wharton's jelly are a rich source of mesenchymal stem cells. They can be easily obtained and grown using the adhesive method. They produce many types of proteins, including VEGF. Their role is to participate in angiogenesis, vasodilation, stimulation of cells to migrate, and chemotactic activity. The aim of this study was to evaluate expression of genes from the vascular endothelial growth factor family: VEGFA, VEGFB and VEGFC in MSC and the analysis of dependence of the expression of the studied genes on clinical factors related to the course of pregnancy and childbirth, and health of mother and child.

Material and Methods

The research material was an umbilical cord obtained from 40 patients hospitalized in the Department of Obstetrics and Pathology of Pregnancy of the Independent Public Clinical Hospital No.1 in Lublin. The age of the women was 21-46, all gave birth by cesarean section. Some of the patients suffered from hypertension and hypothyroidism. Material collected from patients immediately after delivery was subjected to enzymatic digestion with type I collagenase. The isolated cells were then cultured in adherent conditions, and then gene expression was assessed using qPCR and the immunophenotype of the cells was assessed cytometrically.

Results

Conducted studies have shown significant differences in expression of VEGF family genes depending on clinical condition of mother and child. Significant differences in VEGF-family gene expression level in umbilical cord MSC collected from women with hypothyroidism, hypertension, time of labor and birth weight of the baby were shown.

Conclusion

Probably due to hypoxia (caused, for example, by hypothyroidism or hypertension), the MSCs found in the umbilical cord may react with an increased expression of VEGF and a compensatory increase in the amount of secreted factor, the aim of which is, i.a., vasodilation and increase of blood supply to the fetus through the umbilical vessels.

Favorable Biological Performance Regarding the Interaction between Gold Nanoparticles and Mesenchymal Stem Cells

Gold nanoparticles (AuNPs) are well known to interact with cells, leading to different cell behaviors such as cell proliferation and differentiation capacity. Biocompatibility and biological functions enhanced by nanomedicine are the most concerning factors in clinical approaches. In the present research, AuNP solutions were prepared at concentrations of 1.25, 2.5, 5 and 10 ppm for biocompatibility investigations. Ultraviolet-visible spectroscopy was applied to identify the presence of AuNPs under the various concentrations. Dynamic Light Scattering assay was used for the characterization of the size of the AuNPs. The shape of the AuNPs was observed through a Scanning Electron Microscope. Afterward, the mesenchymal stem cells (MSCs) were treated with a differentiation concentration of AuNP solutions in order to measure the biocompatibility of the nanoparticles. Our results demonstrate that AuNPs at 1.25 and 2.5 ppm could significantly enhance MSC proliferation, decrease reactive oxygen species (ROS) generation and attenuate platelet/monocyte activation. Furthermore, the MSC morphology was observed in the presence of filopodia and lamellipodia while being incubated with 1.25 and 2.5 ppm AuNPs, indicating that the adhesion ability was enhanced by the nanoparticles. The expression of matrix metalloproteinase (MMP-2/9) in MSCs was found to be more highly expressed under 1.25 and 2.5 ppm AuNP treatment, relating to better cell migrating ability. Additionally, the cell apoptosis of MSCs investigated with Annexin-V/PI double staining assay and the Fluorescence Activated Cell Sorting (FACS) method demonstrated the lower population of apoptotic cells in 1.25 and 2.5 ppm AuNP treatments, as compared to high concentrations of AuNPs. Additionally, results from a Western blotting assay explored the possibility that the anti-apoptotic proteins Cyclin-D1 and Bcl-2 were remarkably expressed. Meanwhile, real-time PCR analysis demonstrated that the 1.25 and 2.5 ppm AuNP solutions induced a lower expression of inflammatory cytokines (TNF-α, IL-1β, IFN-γ, IL-6 and IL-8). According to the tests performed on an animal model, AuNP 1.25 and 2.5 ppm treatments exhibited the better biocompatibility performance, including anti-inflammation and endothelialization. In brief, 1.25 and 2.5 ppm of AuNP solution was verified to strengthen the biological functions of MSCs, and thus suggests that AuNPs become the biocompatibility nanomedicine for regeneration research.

Sodium hydrosulfide and bone marrow derived mesenchymal stem cells combined therapy for bleomycin induced pulmonary fibrosis in rats: Implication of micro RNA-21 and Lnc GAS5

AIMS

Pulmonary fibrosis (PF) is considered as an end stage for many lung diseases. Mesenchymal stem cells (MSC) as regenerative therapy have become a remarkably valuable therapeutic strategy in different diseases. Hydrogen sulfide has been recently introduced into the medical field for its antifibrotic properties in addition to enhancement of MSC stemness and function. The aim of the present study was to investigate the ability of BM-MSC in combination with NaHS to attenuate Bleomycin induced pulmonary fibrosis was studied in rats. A special emphasis was given to miR-21 and GAS5 as important players in the development of PF.

MAIN METHODS

PF was induced in 32 Wistar male rats by single endotracheal injection of bleomycin, those were randomly divided into four groups (8 rats each): (untreated PF group) - (PF + MSC) treated group- (PF + NaHS treated group) - PF + combined (NAHS + MSC) treated group.

KEY FINDINGS

Induction of PF was associated with increased miR-21 and decreased lncRNA-GAS5 expression. Treatment with either NaHS or BM-MSC leads to an inhibitory effect on pulmonary fibrosis as evidenced by improvement of histopathological studies, pulmonary function tests, reduction of inflammatory and fibrotic markers like Hydroxyproline, TNF α, TGF-β and caspase -3 together with downregulation miR-21 and increase lncRNA-GAS5 expression.

SIGNIFICANCE

The current work revealed the inhibitory effect of combined NaHS and BM-MSC on pulmonary fibrosis with concomitant modulation of miR-21 and lncRNA-GAS5 expression.

The effect of mesenchymal stromal cells ın the microenvironment on cancer development

Inflammatory signals secreted from the tumor microenvironment are thought to promote tumor growth and survival. It has been reported that stromal cells in the tumor microenvironment have similar characteristics to tumor-associated cells. In addition miRNAs play critical roles in various diseases, including cancer. In this study, we aimed to investigate the effects of co-culture of cancer cells and stromal cells isolated from normal and malignant breast tissue on each other and the possible effects of miRNAs on these interactions. The characterized stromal cells were co-cultured with an MDA-MB-231 cancer cell line. The proliferation capacity of the experimental groups was evaluated using the WST-1 assay. The expression of breast cancer-specific miRNAs and related genes were assessed by real-time PCR. ELISA assay was performed to determine the concentration of some cytokines and chemokines. We found that the microenvironment plays an important role in the development of cancer, confirming the changes in the expression of oncogenic and tumor suppressor miRNA and their target genes after co-culture with malignant stromal cells. As a result of the studies, specific gene expressions of related signaling pathways were detected in correlation with miRNA changes and the effects of tumor microenvironment on tumorigenesis were revealed in detail. miRNAs have been shown to play an important role in cancer development in recent studies. The idea that these small molecules can be used in diagnosis and treatment is becoming stronger day by day. We believe that new treatment approaches involving the tumor microenvironment and using miRNAs as markers are promising.

Genetically Engineered Mesenchymal Stem Cell Therapy Against Murine Experimental Autoimmune Encephalomyelitis

We used recombinant interleukin 23 receptor (RIL-23R)-engineered mesenchymal stem cells (MSCs) to study its therapeutic role in enhancing inflammation of nervous tissue in the mouse model (EAE) of multiple sclerosis (MS). Recombinant IL-23 receptor construct was designed to enter MSCs. The bioactivity of the constructs was assessed by the co-culture of MSCs/CD4 + T cells. The EAE model was induced in mice. After cell transplantation, clinical scores were evaluated, and tissue demyelination was measured by Luxol fast blue staining. The transfection of RIL-23R mRNA improved MSC properties significantly to the inflamed regions of EAE mice, and it performed an increased suppressive function on the T lymphocyte proliferation. Furthermore, in vivo therapy with RIL-23R MSCs in EAE mice showed an enhanced therapeutic action than MSCs, proven by improved myelination and a reduction in the penetration of inflammatory cells into the white matter. Our targeted transplantation procedure of modified MSC can be applied to improve the effectiveness of cellular therapy for multiple sclerosis and other autoimmune disorders.

A New Method of Bone Stromal Cell Characterization by Flow Cytometry

The bone microenvironment cellular composition plays an essential role in bone health and is disrupted in bone pathologies, such as osteoporosis, osteoarthritis, and cancer. Flow cytometry protocols for hematopoietic stem cell lineages are well defined and well established. Additionally, a consensus for mesenchymal stem cell flow markers has been developed. However, flow cytometry markers for bone-residing cells-osteoblasts, osteoclasts, and osteocytes-have not been proposed. Here, we describe a novel partial digestion method to separate these cells from the bone matrix and present new markers for enumerating these cells by flow cytometry. We optimized bone digestion and analyzed markers across murine, nonhuman primate, and human bone. The isolation and staining protocols can be used with either cell sorting or flow cytometry. Our method allows for the enumeration and collection of hematopoietic and mesenchymal lineage cells in the bone microenvironment combined with bone-residing stromal cells. Thus, we have established a multi-fluorochrome bone marrow cell-typing methodology. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Partial digestion for murine long bone stromal cell isolation Alternate Protocol 1: Partial digestion for primate vertebrae stromal cell isolation Alternate Protocol 2: Murine vertebrae crushing for bone stromal cell isolation Basic Protocol 2: Staining of bone stromal cells Support Protocol 1: Fluorescence minus one control, isotype control, and antibody titration Basic Protocol 3: Cell sorting of bone stromal cells Alternate Protocol 3: Flow cytometry analysis of bone stromal cells Support Protocol 2: Preparing compensation beads.

Labelling stem cells with a nanoprobe for evaluating the homing behaviour in facial nerve injury repair

It is crucial and clinically relevant to clarify the homing efficiency and retention of stem cells in different implanting strategies of cell therapy for various injuries. However, the need for a tool for investigating the mechanisms is still unmet. We herein introduce multi-modal BaGdF₅:Yb,Tm nanoparticles as a nanoprobe to label adipose-derived stem cells (ADSCs) and detect the homing behavior with a micro-computed tomography (micro-CT) imaging technique. The migration of cells injected locally or intravenously, with or without a chemokine, CXCL 12, was compared. A higher homing efficiency of ADSCs was observed in both intravenously injected groups, in contrast to the low efficiency of cell retention in local implantation. Meanwhile, CXCL 12 promoted the homing of ADSCs, especially in the intravenous route. Nonetheless, the administration of CXCL 12 showed its therapeutic efficacy, whereas intravenous injection of ADSCs almost did not. Our work provided a tool for in vivo imaging of the behavior of implanted cells in preclinical studies of cell therapy, and more importantly, implied that the parameters for implanting stem cells in clinical operation should be carefully considered.

Relevance of Cellular Redox Homeostasis for Vital Functions of Human Dental Pulp Cells

Odontogenic MSCs are vulnerable to LPS-triggered bacterial infections, and they respond by secreting inflammatory mediators, such as IL-6, and with mineralization. Since both processes might be prone to a disturbance of the redox homeostasis, the oxidative stress influence on vital functions of human dental pulp cells (HPCs) was investigated. With these aims, a model of LPS-stimulated primary HPCs was established, and anti- and pro-oxidant substances were administered up to 21 days to measure inflammation and mineralization parameters. LPS-stimulated HPCs retained mineralization potential, which was decreased with the antioxidants NAC and fisetin and the pro-oxidant BSO. The expression of surface markers related to odontogenic commitment was influenced accordingly but counteracted by the enhanced expression of BMP2 and ALP at the transcriptional level. LPS triggers an early IL-6 production in non-odontogenic conditions, while it can be measured only after 15 days in the presence of the differentiation medium. The present study shows that HPCs functions causally depend on a tightly regulated cellular redox balance. Our data demonstrate a redox control of pulp MSC odontogenic commitment along with a potential association between an IL-6 late secretion and mineralization. These findings lay the groundwork for investigations on the molecular role of IL-6 in dental hard tissue metabolism.

The application of regenerative medicine in colorectal surgery

Tissue reconstruction and regeneration represent one of the greatest challenges in any surgical field. Regenerative medicine combined with stem cell-based therapy is a novel and promising field of medicine. Stem cells possess the ability to differentiate into specialized cells and to decrease inflammation and therefore can play a role in repair or regeneration of damaged tissues. Colorectal surgery often deals with infected, poorly vascularized, radiated, and inflamed tissue, as well as instances where imperfect healing might have grave implications. This problem has led researchers to study utilizing stem cells in many colorectal conditions, such as anastomotic healing, perianal fistulae, rectovaginal fistulae, anal fissure, and fecal incontinence. The purpose of this review was to discuss prominent studies that explored stem cells utilization in treating different colorectal pathologies.

Mesenchymal Stem Cells as a Cornerstone in a Galaxy of Intercellular Signals: Basis for a New Era of Medicine

Around 40% of the population will suffer at some point in their life a disease involving tissue loss or an inflammatory or autoimmune process that cannot be satisfactorily controlled with current therapies. An alternative for these processes is represented by stem cells and, especially, mesenchymal stem cells (MSC). Numerous preclinical studies have shown MSC to have therapeutic effects in different clinical conditions, probably due to their mesodermal origin. Thereby, MSC appear to play a central role in the control of a galaxy of intercellular signals of anti-inflammatory, regenerative, angiogenic, anti-fibrotic, anti-oxidative stress effects of anti-apoptotic, anti-tumor, or anti-microbial type. This concept forces us to return to the origin of natural physiological processes as a starting point to understand the evolution of MSC therapy in the field of regenerative medicine. These biological effects, demonstrated in countless preclinical studies, justify their first clinical applications, and draw a horizon of new therapeutic strategies. However, several limitations of MSC as cell therapy are recognized, such as safety issues, handling difficulties for therapeutic purposes, and high economic cost. For these reasons, there is an ongoing tendency to consider the use of MSC-derived secretome products as a therapeutic tool, since they reproduce the effects of their parent cells. However, it will be necessary to resolve key aspects, such as the choice of the ideal type of MSC according to their origin for each therapeutic indication and the implementation of new standardized production strategies. Therefore, stem cell science based on an intelligently designed production of MSC and or their derivative products will be able to advance towards an innovative and more personalized medical biotechnology.

Structural and chemical role of mesenchymal stem cells and resveratrol in regulation of apoptotic -induced genes in Bisphenol-A induced uterine damage in adult female albino rats

The probable beneficial effects of mesenchymal stem cells (MSCs) and resveratrol were assessed in an experimental model of Bisphenol-A (BPA)-evident uterine damage in rats. Thirty-five albino rats were involved and equally divided into five groups: Group I: negative control rats received usual diet, Group II: positive control rats received BPA by oral gavage for 15 days, Group III: BPA-treated rats received single oral gavage of resveratrol daily for two weeks, Group IV: BPA-treated rats received a single intravenous dose of MSCs and Group V: BPA-treated rats received combined treatment of resveratrol and MSCs. Oxidative stress markers, apoptosis-related genes, and gonadal hormones were assessed. Histological and immunohistochemical examination of uterine tissue was conducted for TGF-β 1. Caspases-3, 8, and 9 (Casp3, Casp8, Casp9) genes were assessed in uterine tissues by quantitative real-time PCR. Results revealed that BPA induced significant changes in the endometrial tissue, inflammatory cell infiltration, focal blood extravasation, increase in collagen fibers, decrease in PAS staining, and increase in TGF-β 1 immunoreactivity. BPA also induced a significant increase in oxidative stress markers; malondialdehyde (MDA), SOD, CAT, and apoptosis-related genes. BPA induced a significant change in blood levels of gonadal hormones; a significant increase in FSH and a significant decrease in estradiol (E2) and progesterone (P). Treatment with either resveratrol, MSCs, or a combination of them resulted in significant enhancement of histological findings, restoration of gonadal hormones to near-normal levels, and a significant decrease in oxidative stress markers and apoptosis genes. Combined treatment with resveratrol and MSCs demonstrated more significant therapeutic effects as regard to the studied parameters in association with rat groups treated with either MSCs or resveratrol separately.

Cytochalasin B-Induced Membrane Vesicles from Human Mesenchymal Stem Cells Overexpressing IL2 Are Able to Stimulate CD8+ T-Killers to Kill Human Triple Negative Breast Cancer Cells

Simple Summary

Almost all human cells release extracellular vesicles participating in intercellular communication. Extracellular vesicles are rounded structures surrounded by the cytoplasmic membrane, which embody cytoplasmic contents of the parental cells, which makes extracellular vesicles a promising therapeutic tool for cell-free cancer therapy. In this study, human mesenchymal stem cells were genetically modified to overexpress human interleukin-2 (IL2), a cytokine which regulates the proliferation and activation of immune cells. Membrane vesicle release from native and genetically modified stem cells was induced by cytochalasin B treatment to increase the yield of membrane vesicles. To evaluate the immunomodulating properties of isolated membrane vesicles, immune cells were isolated from human peripheral blood and co-cultured with membrane vesicles from native or IL2 overexpressing stem cells. To analyze the anti-tumor activity of immune cells after interaction with IL2-enriched membrane vesicles, immune cells were co-cultured with triple negative breast cancer cells. As a result, IL2-enriched membrane vesicles were able to activate and stimulate the proliferation of immune cells, which in turn were able to induce apoptosis in breast cancer cells. Therefore, the production of IL2-enriched membrane vesicles represents a unique opportunity to meet the potential of extracellular vesicles to be used in clinical applications for cancer therapy.

Abstract

Interleukin 2 (IL2) was one of the first cytokines used for cancer treatment due to its ability to stimulate anti-cancer immunity. However, recombinant IL2-based therapy is associated with high systemic toxicity and activation of regulatory T-cells, which are associated with the pro-tumor immune response. One of the current trends for the delivery of anticancer agents is the use of extracellular vesicles (EVs), which can carry and transfer biologically active cargos into cells. The use of EVs can increase the efficacy of IL2-based anti-tumor therapy whilst reducing systemic toxicity. In this study, human adipose tissue-derived mesenchymal stem cells (hADSCs) were transduced with lentivirus encoding IL2 (hADSCs-IL2). Membrane vesicles were isolated from hADSCs-IL2 using cytochalasin B (CIMVs-IL2). The effect of hADSCs-IL2 and CIMVs-IL2 on the activation and proliferation of human peripheral blood mononuclear cells (PBMCs) as well as the cytotoxicity of activated PBMCs against human triple negative cancer MDA-MB-231 and MDA-MB-436 cells were evaluated. The effect of CIMVs-IL2 on murine PBMCs was also evaluated in vivo. CIMVs-IL2 failed to suppress the proliferation of human PBMCs as opposed to hADSCs-IL2. However, CIMVs-IL2 were able to activate human CD8⁺ T-killers, which in turn, killed MDA-MB-231 cells more effectively than hADSCs-IL2-activated CD8⁺ T-killers. This immunomodulating effect of CIMVs-IL2 appears specific to human CD8⁺ T-killer cells, as the same effect was not observed on murine CD8⁺ T-cells. In conclusion, the use of CIMVs-IL2 has the potential to provide a more effective anti-cancer therapy. This compelling evidence supports further studies to evaluate CIMVs-IL2 effectiveness, using cancer mouse models with a reconstituted human immune system.

Exosomes derived from miR-34a-overexpressing mesenchymal stem cells inhibit in vitro tumor growth: A new approach for drug delivery

AIMS

Exosomes hold great promise as bio-inspired delivery vehicles. Mesenchymal stem cells (MSCs) are recognized for their potential to yield huge quantities of exosomes. We aimed to investigate the potential use of modified exosomes derived from genetically modified dental pulp MSCs (DPSCs) as a carrier to deliver tumor suppressor miR-34a to repress proliferation of breast carcinoma cells.

MATERIALS AND METHODS

miR-34a-overexpressing DPSCs were prepared using XMIRXpress-34a lentivectors. The anticancer effects of the miR-34a-loaded exosomes were evaluated on breast carcinoma cells through apoptosis, migration, and invasion assays. Given the structural similarity between exosomes and liposomes, we compared the exosome-mediated miRNA delivery efficiency with that of liposomes.

KEY FINDINGS

Our data demonstrated that genetically modified DPSCs were capable of secretion of exosomes enriched with therapeutic miRNAs and presented the feasibility of application of exosome-based vehicle for gene delivery.

SIGNIFICANCE

We showed the potential of MSC-derived exosomes as a tool for delivery of miRNAs in vitro. Nevertheless, optimizing gene-loading approaches is required before exosomes can be intended as a miRNA carrier for therapeutic applications.

Distinguished properties of cells isolated from the dentin-pulp interface

BACKGROUND

Dental odontoblasts produce dentin mineralized matrix, trigger immune responses and act as sensory cells. The understanding of the mechanisms of these functions has been particularly restricted due to the lack of odontoblasts being cultivable in vitro. Because of the lack of specific markers to identify cells of the odontoblastic lineage, properties of the cells isolated from the dentin-pulp interface were compared to dental pulp cells, periodontal ligament cells, osteoblasts, skin fibroblasts, epithelial cells (A549) and HeLa in the present study.

METHODS

After surgical procedures, the pulp tissue was removed from the tooth crown, and cells were scrapped off the dentin-pulp interface. Explants from teeth of three patients were routinely cultivated, and cells were harvested after several weeks. Cell morphology and ultrastructure was studied by light microscopy (LM), scanning (SEM) or transmission electron microscopy (TEM). Expression of dentin sialophosphoprotein (DSPP), dentin matrix protein 1 (DMP1), TRPV4, and S100 calcium binding protein A4 (S100A4) were analyzed at the protein level by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting using specific antibodies. The differential expression of S100A4 in the various cell lines was further investigated at the gene level by semiquantitative real-time PCR. Mineralization in the various cell types was observed after alizarin red staining after a 28 days incubation period. The immunophenotype of the cells was examined by flow cytometry using monoclonal anti-human antibodies CD90-FITC, CD73-PE, CD105-PE, CD29-PE, CD140a-FITC, CD144-PE, CD45-FITC or CD34-FITC. Differences between median values were statistically analyzed (Mann-Whitney U-test).

RESULTS

Cells from the dentin-pulp interface retain the polarity of odontoblast morphology in culture with an elongated, rounded cell body, and an extended cellular process. Ultrastructural analysis of the cells indicates high secretory activity including the extracellular deposition of fibrillar collagen. An extended rough endoplasmic reticulum is lined by a large number of ribosomes, and a vast number of secretory granules merges with the cell membrane. Protein expression of DSPP, DMP1, and TRPV4 as a transient receptor potential cation was detected in all cell lines. S100A4 was found differentially expressed in cultures of cells from tooth tissues. High expression of S100A4 was observed at the protein and gene level in two fractions of cells isolated from the dentin-pulp interface, but was absent or only weakly expressed in pulp cells. S100A4 expression in cells from the dentin-pulp interface and pulp cells is consistent with the intensity of the formation of mineralized nodules detected by alizarin red staining. Immunophenotyping revealed that a high percentage of CD73 (ecto-5-nucleotidase), an enzyme active on the surface of immune-competent cells, was expressed in cells of the dentin-pulp interface. While 72%-78% of positive cells were detected in dentin-pulp interface fractions, only 28-64% of the cells in pulp cell cultures were stained.

CONCLUSIONS

The present findings obtained with a variety of cells of different origin provide experimental evidence that cells isolated from the dentin-pulp interface express unique properties different from dental pulp cells in particular. The differential expression of S100A4 is a relevant marker candidate for differentiating between dental pulp cells and cells of the odontoblast lineage.

Role of oxidative metabolism in osseointegration during spinal fusion

Spinal fusion is a commonly performed orthopedic surgery. Autologous bone graft obtained from the iliac crest is frequently employed to perform spinal fusion. Osteogenic bone marrow stromal (a.k.a. mesenchymal stem) cells (BMSCs) are believed to be responsible for new bone formation and development of the bridging bone during spinal fusion, as these cells are located in both the graft and at the site of fusion. Our previous work revealed the importance of mitochondrial oxidative metabolism in osteogenic differentiation of BMSCs. Our objective here was to determine the impact of BMSC oxidative metabolism on osseointegration of the graft during spinal fusion. The first part of the study was focused on correlating oxidative metabolism in bone graft BMSCs to radiographic outcomes of spinal fusion in human patients. The second part of the study was focused on mechanistically proving the role of BMSC oxidative metabolism in osseointegration during spinal fusion using a genetic mouse model. Patients’ iliac crest-derived graft BMSCs were identified by surface markers. Mitochondrial oxidative function was detected in BMSCs with the potentiometric probe, CMXRos. Spinal fusion radiographic outcomes, determined by the Lenke grade, were correlated to CMXRos signal in BMSCs. A genetic model of high oxidative metabolism, cyclophilin D knockout (CypD KO), was used to perform spinal fusion in mice. Graft osseointegration in mice was assessed with micro-computed tomography. Our study revealed that higher CMXRos signal in patients’ BMSCs correlated with a higher Lenke grade. Mice with higher oxidative metabolism (CypD KO) had greater mineralization of the spinal fusion bridge, as compared to the control mice. We therefore conclude that higher oxidative metabolism in BMSCs correlates with better spinal fusion outcomes in both human patients and in a mouse model. Altogether, our study suggests that promoting oxidative metabolism in osteogenic cells could improve spinal fusion outcomes for patients.

Application of Mesenchymal Stem Cells in Inflammatory and Fibrotic Diseases

Mesenchymal stem cells (MSCs) are multipotent stem cells that can be isolated from various tissues in the adult body. MSCs should be characterized by three criteria for regenerative medicine. MSCs must (1) adhere to plastic surfaces, (2) express specific surface antigens, and (3) differentiate into mesodermal lineages, including chondrocytes, osteoblasts, and adipocytes, in vitro. Interestingly, MSCs have immunomodulatory features and secrete trophic factors and immune receptors that regulate the microenvironment in host tissue. These specific and unique therapeutic properties make MSCs ideal as therapeutic agents in vivo. Specifically, pre-clinical and clinical investigators generated inflammatory and fibrotic diseases models, and then transplantation of MSCs into diseases models for therapeutic effects investigation. In this review, we characterize MSCs from various tissues and describe their applications for treating various inflammation and fibrotic diseases.

In Vitro Cultures of Adipose-Derived Stem Cells: An Overview of Methods, Molecular Analyses, and Clinical Applications

Adipose-derived stem cells (ASCs) exhibiting mesenchymal stem cell (MSC) characteristics, have been extensively studied in recent years. Because they have been shown to differentiate into lineages such as osteogenic, chondrogenic, neurogenic or myogenic, the focus of most of the current research concerns either their potential to replace bone marrow as a readily available and abundant source of MSCs, or to employ them in regenerative and reconstructive medicine. There is close to consensus regarding the methodology used for ASC isolation and culture, whereas a number of molecular analyses implicates them in potential therapies of a number of pathologies. When it comes to clinical application, there is a range of examples of animal trials and clinical studies employing ASCs, further emphasizing the advancement of studies leading to their more widespread use. Nevertheless, in vitro studies will most likely continue to play a significant role in ASC studies, both providing the molecular knowledge of their ex vivo properties and possibly serving as an important step in purification and application of those cells in a clinical setting. Therefore, it is important to consider current methods of ASC isolation, culture, and processing. Furthermore, molecular analyses and cell surface properties of ASCs are essential for animal studies, clinical studies, and therapeutic applications of the MSC properties.

Functional heterogeneity of mesenchymal stem cells from natural niches to culture conditions: implications for further clinical uses

Mesenchymal stem cells (MSC) are present in all organs and tissues. Several studies have shown the therapeutic potential effect of MSC or their derived products. However, the functional heterogeneity of MSC constitutes an important barrier for transferring these capabilities to the clinic. MSC heterogeneity depends on their origin (biological niche) or the conditions of potential donors (age, diseases or unknown factors). It is accepted that many culture conditions of the artificial niche to which they are subjected, such as O₂ tension, substrate and extracellular matrix cues, inflammatory stimuli or genetic manipulations can influence their resulting phenotype. Therefore, to attain a more personalized and precise medicine, a correct selection of MSC is mandatory, based on their functional potential, as well as the need to integrate all the existing information to achieve an optimal improvement of MSC features in the artificial niche.

The Small GTPases Rab27b Regulates Mitochondrial Fatty Acid Oxidative Metabolism of Cardiac Mesenchymal Stem Cells

Cardiac mesenchymal stem cells (C-MSCs) are endogenous cardiac stromal cells that play a crucial role in maintaining normal cardiac function. Rab27b is a member of the small GTPase Rab family that controls membrane trafficking and the secretion of exosomes. However, its role in regulating energy metabolism in C-MSC is unclear. In this study, we analyzed mitochondrial oxidative phosphorylation by quantifying cellular oxygen consumption rate (OCR) and quantified the extracellular acidification rate (ECAR) in C-MSC with/without Rab27b knockdown. Knockdown of Rab27b increased glycolysis, but significantly reduced mitochondrial oxidative phosphorylation (OXPHOS) with loss of mitochondrial membrane potential in C-MSC. Furthermore, knockdown of Rab27b reduced H3k4me3 expression in C-MSC and selectively decreased the expression of the essential genes involved in β-oxidation, tricarboxylic acid cycle (TCA), and electron transport chain (ETC). Taken together, our findings highlight a novel role for Rab27b in maintaining fatty acid oxidation in C-MSCs.

A comparison of the use of adipose-derived and bone marrow-derived stem cells for peripheral nerve regeneration in vitro and in vivo

Background

To date, it has repeatedly been demonstrated that infusing bone marrow-derived stem cells (BMSCs) into acellular nerve scaffolds can promote and support axon regeneration through a peripheral nerve defect. However, harvesting BMSCs is an invasive and painful process fraught with a low cellular yield.

Methods

In pursuit of alternative stem cell sources, we isolated stem cells from the inguinal subcutaneous adipose tissue of adult Sprague–Dawley rats (adipose-derived stem cells, ADSCs). We used a co-culture system that allows isolated adult mesenchymal stem cells (MSCs) and Schwann cells (SCs) to grow in the same culture medium but without direct cellular contact. We verified SC phenotype in vitro by cell marker analysis and used red fluorescent protein-tagged ADSCs to detect their fate after being injected into a chemically extracted acellular nerve allograft (CEANA). To compare the regenerative effects of CEANA containing either BMSCs or ADSCs with an autograft and CEANA only on the sciatic nerve defect in vivo, we performed histological and functional assessments up to 16 weeks after grafting.

Results

In vitro, we observed reciprocal beneficial effects of ADSCs and SCs in the ADSC–SC co-culture system. Moreover, ADSCs were able to survive in CEANA for 5 days after in vitro implantation. Sixteen weeks after grafting, all results consistently showed that CEANA infused with BMSCs or ADSCs enhanced injured sciatic nerve repair compared to the acellular CEANA-only treatment. Furthermore, their beneficial effects on sciatic injury regeneration were comparable as histological and functional parameters evaluated showed no statistically significant differences. However, the autograft group was roundly superior to both the BMSC- or ADSC-loaded CEANA groups.

Conclusion

The results of the present study show that ADSCs are a viable alternative stem cell source for treating sciatic nerve injury in lieu of BMSCs.

Extracellular matrix mimicking polycaprolactone-chitosan nanofibers promote stemness maintenance of mesenchymal stem cells via spheroid formation

The development of clinical applications has led to a perpetual increase in the demand for mesenchymal stem cells (MSCs). However, the ex vivo expansion of MSCs while maintaining their stemness and differentiation potential remains an immense challenge. MSCs require high cell density for their intercellular communication and specific physico-chemical cues from the surrounding environment for spheroid formation in order to maintain their stemness. Inadequacy of the traditional in vitro cell culture method (tissue culture plastic surface) to fulfill any of these special requirements is responsible for inducing the loss of stem cell properties of the MSCs over time. In this study, we propose that glucosaminoglycan (GAG) mimicking ultrafine nanofibers could support the spheroid culture for in vitro human MSC expansion. The geometrical and biochemical properties of nanofibers provide biomimicking cues to MSCs, as well as enhance cell-cell interactions and stimulate spheroid formation in MSCs, which subsequently result in increased cell proliferation, enhanced expression of stem cell markers and maintenance of their multilineage differentiation potential. Furthermore, close monitoring of the behavior of MSCs on nanofibers serves as the key to understand their mode of action in niche formation. Interestingly, GAG mimicking substrate stimulated MSCs for long-distance intercellular communication via 'tunneling tubes', their subsequent migration and niche formation. These kinds of cellular interactions over long distances have rarely been observed in MSCs to provide better insight for future studies on MSC niche. Furthermore, PCL-CHT nanofibers were observed to be as conducive to use as tissue culture polystyrene for stem cell expansion. Overall, these polymeric nanofibers provide a more relevant, convenient and more suitable substrate than the conventional monolayer culture for in vitro MSC expansion.

Mesenchymal stem cells as carriers for systemic delivery of oncolytic viruses

Progress in genetic engineering led to the emergence of some viruses as potent anticancer therapeutics. These oncolytic viruses combine self-amplification with dual antitumor action: oncolytic (destruction of cancer cells) and immunostimulatory (eliciting acquired antitumor response against cancer epitopes). As any other viruses, they trigger antiviral response upon systemic administration. Mesenchymal stem cells are immature cells capable of self-renewing and differentiating into many cell types that belong to three germinal layers. Due to their inherent tumor tropism mesenchymal stem cells loaded with oncolytic virus can improve delivery of the therapeutic cargo to cancer sites. Shielding of oncolytic viral construct from antiviral host immune response makes these cells prospective delivery vehicles to even hard-to-reach metastatic neoplastic foci. Use of mesenchymal stem cells has been criticized by some investigators as limiting proliferative abilities of primary cells and increasing the risk of malignant transformation, as well as attenuating therapeutic responses. However, majority of preclinical studies indicate safety and efficacy of mesenchymal stem cells used as carriers of oncolytic viruses. In view of contradictory postulates, the debate continues. The review discusses mesenchymal stem cells as carriers for delivery of genetically engineered oncolytic constructs and focuses on systemic approach to oncoviral treatment of some deadly neoplasms.

Stem cells out of the bag: characterization of ex vivo expanded mesenchymal stromal cells for possible clinical use

Aim:

Mesenchymal stromal cells (MSC) are a promising tool for cellular therapy and regenerative medicine. One major difficulty in establishing a MSC expansion protocol is the large volume of bone marrow (BM) required. We studied whether cells trapped within a collection bag and filter system could be considered as a source of MSC.

Results:

From the 20 BM collection bag and filter systems, we recovered an average of 1.68 × 10⁸ mononuclear cells, which is the equivalent to 60 ml of filtered BM. Mononuclear cells were expanded ex vivo to 17 × 10⁶ MSC, with purity shown by a CD44⁺, CD105⁺, CD90⁺ and CD73⁺ immunophenotype, a reduction of 20% proliferating cells in a mixed lymphocyte reaction and also the ability of adipocyte differentiation.

Conclusion:

Long-term MSC cultures were established from the usually discarded BM collection bag and filter, maintaining an appropriate phenotype and function, being suitable for both investigation and clinical settings.

Mesenchymal stromal cells (MSC) are a promising tool for cellular therapy and regenerative medicine. One major difficulty in obtaining MSC is the large volume of bone marrow (BM) required from a healthy donor. From usually discarded collection bags of BM collected for transplant, we recovered a number of cells equivalent to 60 ml of BM and expanded functional MSC with high purity. We believe that those recovered cells are an alternative to BM for obtaining MSC. The routinely recovery of such cells in reference centers, in a way similar to a public cord-blood bank, could benefit the scientific community, once further research is conducted to confirm results.

RNAase III-Type Enzyme Dicer Regulates Mitochondrial Fatty Acid Oxidative Metabolism in Cardiac Mesenchymal Stem Cells

Cardiac mesenchymal stem cells (C-MSC) play a key role in maintaining normal cardiac function under physiological and pathological conditions. Glycolysis and mitochondrial oxidative phosphorylation predominately account for energy production in C-MSC. Dicer, a ribonuclease III endoribonuclease, plays a critical role in the control of microRNA maturation in C-MSC, but its role in regulating C-MSC energy metabolism is largely unknown. In this study, we found that Dicer knockout led to concurrent increase in both cell proliferation and apoptosis in C-MSC compared to Dicer floxed C-MSC. We analyzed mitochondrial oxidative phosphorylation by quantifying cellular oxygen consumption rate (OCR), and glycolysis by quantifying the extracellular acidification rate (ECAR), in C-MSC with/without Dicer gene deletion. Dicer gene deletion significantly reduced mitochondrial oxidative phosphorylation while increasing glycolysis in C-MSC. Additionally, Dicer gene deletion selectively reduced the expression of β-oxidation genes without affecting the expression of genes involved in the tricarboxylic acid (TCA) cycle or electron transport chain (ETC). Finally, Dicer gene deletion reduced the copy number of mitochondrially encoded 1,4-Dihydronicotinamide adenine dinucleotide (NADH): ubiquinone oxidoreductase core subunit 6 (MT-ND6), a mitochondrial-encoded gene, in C-MSC. In conclusion, Dicer gene deletion induced a metabolic shift from oxidative metabolism to aerobic glycolysis in C-MSC, suggesting that Dicer functions as a metabolic switch in C-MSC, which in turn may regulate proliferation and environmental adaptation.

Bone Marrow-Derived Mesenchymal Stem Cell Potential Regression of Dysplasia Associating Experimental Liver Fibrosis in Albino Rats

Objectives

Assessing the therapeutic efficacy of superparamagnetic iron oxide nanoparticles (SPIO) labeled bone marrow-derived mesenchymal stem cells (BM-MSCs) on experimental liver fibrosis and associated dysplasia.

Materials and Methods

MSCs were obtained from 10 male Sprague-Dawley rats while 50 female rats were divided into control (CG), liver fibrosis (CCL4, intraperitoneal injection of CCl₄ for 8 weeks), and CCL₄ rats treated with SPIO-labeled MSCs (MSCs/CCl₄) with and without continuing CCL₄ injection for another 8 weeks. Assessment included liver histopathology, liver function tests, transmission electron microscopic tracing for homing of SPIO-MSCs, immunofluorescence histochemistry for fibrosis and dysplasia markers (transforming growth factor-beta (TGF-β1), proliferation nuclear antigen (PCNA), glypican 3)), and quantitative gene expression analysis for matrix metalloproteinase-1 (MMP-1) and tissue inhibitor of metalloproteinase-1 (TIMP-1).

Results

SPIO-labeled MSCs were engrafted in the fibrotic liver and the BM/MSCs demonstrated regression for fibrous tissue deposition and inhibition progression of dysplastic changes in the liver of CCl₄-treated rats on both the histological and molecular levels.

Conclusion

BM-MSCs possess regenerative and antidysplastic potentials.

Establishment of a novel cancer cell line derived from vulvar carcinoma associated with lichen sclerosus exhibiting a fibroblast-dependent tumorigenic potential

Vulvar squamous cell carcinoma associated with lichen sclerosus (VLS-VSCC) are rare tumors but with higher recurrence and worse prognosis than other types of VSCC. Lack of experimental models has limited the search for better understanding of the biology and development of treatment modalities. In this study, we isolated and characterized primary cells from VSCC (n = 7) and normal vulvar tissue adjacent to tumor (n = 7). Detailed characterization of the novel spontaneously immortalized cell line, VCC1 revealed a characteristic epithelial morphology in vitro and a well-differentiated keratinizing SCC histology in vivo, closely resembling the tumor of origin. VCC1 expressed higher levels of epithelial-mesenchymal transition markers and higher clonogenic properties as compared to other established non VLS-VSCC cell lines. In vitro 3D organotypic assays and in vivo xenografts revealed a prominent role of cancer-associated fibroblasts in VCC1 invasion and tumor formation. In conclusion, VCC1 mirrored several major VLS-VSCC features and provided a robust experimental tool for further elucidation of VLS-related oncogenesis and drug testing.

Combination of Chemical and Neurotrophin Stimulation Modulates Neurotransmitter Receptor Expression and Activity in Transdifferentiating Human Adipose Stromal Cells

Adipose stromal cells are promising tools for clinical applications in regeneration therapies, due to their ease of isolation from tissue and its high yield; however, their ability to transdifferentiate into neural phenotypes is still a matter of controversy. Here, we show that combined chemical and neurotrophin stimulation resulted in neuron-like morphology and regulated expression and activity of several genes involved in neurogenesis and neurotransmission as well as ion currents mediated by NMDA and GABA receptors. Among them, expression patterns of genes coding for kinin-B1 and B2, α7 nicotinic, M1, M3 and M4 muscarinic acetylcholine, glutamatergic (AMPA2 and mGlu2), purinergic P2Y1 and P2Y4 and GABAergic (GABA-A, β3-subunit) receptors and neuronal nitric oxide synthase were up-regulated compared to levels of undifferentiated cells. Simultaneously, expression levels of P2X1, P2X4, P2X7 and P2Y6 purinergic and M5 muscarinic acetylcholine receptors were down-regulated. Agonist-induced activity levels of the studied receptor classes also augmented during neuronal transdifferentiation. Transdifferentiated cells expressed high levels of neuronal β3-tubulin, NF-H, NeuN and MAP-2 proteins as well as increased ASCL1, MYT1 and POU3F2 gene expression known to drive neuronal fate determination. The presented work contributes to a better understanding of transdifferentiation induced by neurotrophins for a prospective broad spectrum of medical applications.

Mesenchymal Stem Cells in Homeostasis and Systemic Diseases: Hypothesis, Evidences, and Therapeutic Opportunities

Mesenchymal stem cells (MSCs) are present in all organs and tissues, playing a well-known function in tissue regeneration. However, there is also evidence indicating a broader role of MSCs in tissue homeostasis. In vivo studies have shown MSC paracrine mechanisms displaying proliferative, immunoregulatory, anti-oxidative, or angiogenic activity. In addition, recent studies also demonstrate that depletion and/or dysfunction of MSCs are associated with several systemic diseases, such as lupus, diabetes, psoriasis, and rheumatoid arthritis, as well as with aging and frailty syndrome. In this review, we hypothesize about the role of MSCs as keepers of tissue homeostasis as well as modulators in a variety of inflammatory and degenerative systemic diseases. This scenario opens the possibility for the use of secretome-derived products from MSCs as new therapeutic agents in order to restore tissue homeostasis, instead of the classical paradigm "one disease, one drug".

Generation of Functional Human Adipose Tissue in Mice from Primed Progenitor Cells

Adipose tissue (AT) is used extensively in reconstructive and regenerative therapies, but transplanted fat often undergoes cell death, leading to inflammation, calcification, and requirement for further revision surgery. Previously, we have found that mesenchymal progenitor cells within human AT can proliferate in three-dimensional culture under proangiogenic conditions. These cells (primed ADipose progenitor cells, PADS) robustly differentiate into adipocytes in vitro (ad-PADS). The goal of this study is to determine whether ad-PADS can form structured AT in vivo, with potential for use in surgical applications. Grafts formed from ad-PADS were compared to grafts formed from AT obtained by liposuction after implantation into nude mice. Graft volume was measured by microcomputed tomography scanning, and the functionality of cells within the graft was assessed by quantifying circulating human adiponectin. The degree of graft vascularization by donor or host vessels and the content of human or mouse adipocytes within the graft were measured using species-specific endothelial and adipocyte-specific quantitative real time polymerase chain reaction probes, and histochemistry with mouse and human-specific lectins. Our results show that ad-PADS grafted subcutaneously into nude mice induce robust vascularization from the host, continue to increase in volume over time, express the human adipocyte marker PLIN1 at levels comparable to human AT, and secrete increasing amounts of human adiponectin into the mouse circulation. In contrast, grafts composed of AT fragments obtained by liposuction become less vascularized, develop regions of calcification and decreased content of PLIN1, and secrete lower amounts of adiponectin per unit volume. Enrichment of liposuction tissue with ad-PADS improves vascularization, indicating that ad-PADS may be proangiogenic. Mechanistically, ad-PADS express an extracellular matrix gene signature that includes elements previously associated with small vessel development (COL4A1). Thus, through the formation of a proangiogenic environment, ad-PADS can form functional AT with capacity for long-term survival, and can potentially be used to improve outcomes in reconstructive and regenerative medicine.

Identification of Embryonic Neural Plate Border Stem Cells and Their Generation by Direct Reprogramming from Adult Human Blood Cells

We report the direct reprogramming of both adult human fibroblasts and blood cells into induced neural plate border stem cells (iNBSCs) by ectopic expression of four neural transcription factors. Self-renewing, clonal iNBSCs can be robustly expanded in defined media while retaining multilineage differentiation potential. They generate functional cell types of neural crest and CNS lineages and could be used to model a human pain syndrome via gene editing of SCN9A in iNBSCs. NBSCs can also be derived from human pluripotent stem cells and share functional and molecular features with NBSCs isolated from embryonic day 8.5 (E8.5) mouse neural folds. Single-cell RNA sequencing identified the anterior hindbrain as the origin of mouse NBSCs, with human iNBSCs sharing a similar regional identity. In summary, we identify embryonic NBSCs and report their generation by direct reprogramming in human, which may facilitate insights into neural development and provide a neural stem cell source for applications in regenerative medicine.

The Human IL-23 Decoy Receptor Inhibits T-Cells Producing IL-17 by Genetically Engineered Mesenchymal Stem Cells

The immunomodulatory and self-renewable features of human adipose mesenchymal stem cells (hAD-MSCs) mark their importance in regenerative medicine. Interleukin 23 (IL- 23) as a proinflammatory cytokine suppresses T regulatory cells (Treg) and promotes the response of T helper 17 (Th17) and T helper 1 (Th1) cells. This pathway starts inflammation and immunosuppression in several autoimmune diseases. The current study for producing recombinant IL- 23 decoy receptor (RIL- 23R) using hAD-MSCs as a good candidate for ex vivo cell-based gene therapy purposes reducing inflammation in autoimmune diseases. hAD-MSCs was isolated from lipoaspirate and then characterized by differentiation. RIL- 23R was designed and cloned into a pCDH-813A- 1 lentiviral vector. The transduction of hAD-MSCs was performed at MOI (multiplicity of infection) = 50 with pCDH- EFI α- RIL- 23R- PGK copGFP. Expressions of RIL- 23R and octamer-binding transcription factor 4 (OCT- 4) were determined by real-time polymerase chain reaction (real time-PCR). Self-renewing properties were assayed with OCT- 4. Bioactivity of the designed RIL- 23R was evaluated by IL- 17 and IL- 10 expression of mouse splenocytes. Cell differentiation confirmed the true isolation of hAD-MSCs from lipoaspirate. Restriction of the enzyme digestion and sequencing verified the successful cloning of RIL- 23R in the CD813A-1 lentiviral vector. The green fluorescent protein (GFP) positive transduction rate was up to 90%, and real-time PCR showed the expression level of RIL-23R. Oct-4 had a similar expression pattern with nontransduced hAD-MSCs and transduced hAD-MSCs/ RIL-23R indicating that lentiviral vector did not affect hAD-MSCs characteristics. Downregulation of IL-17 and upregulation of IL-10 showed the correct activity of the engineered hAD-MSCs. The results showed that the transduced hAD-MSCs/ RIL- 23R, expressing IL-23 decoy receptor, can give a useful approach for a basic research on cell-based gene therapy for autoimmune disorders.

Expression patterns of mesenchymal stem cell-specific proteins in adipose tissue-derived cells: possible immunosuppressing agent in partial allograft for restoring the urinary bladder in rabbits

ABSTRACT: Adipose tissue-derived stem cells (ADSCs) are an attractive source of mesenchymal stem cells (MSCs) for use in tissue engineering and clinical applications. This paper focuses on the characterization of ADSCs used as immunosuppressive agent in rabbits undergoing partial allograft for urine bladder restorage. For this study highlighted the characterization of the ADSCs used as immunosuppressive agents in rabbits submitted to partial allograft for restoration of the urinary vesicle, using 25 animals, six months old, New Zealand. ADSCs at the third peal were characterized by the MSC-specific CD105, CD73 and CD90 expression and by the absence of the hematopoietic marker CD45, as revealed by flow cytometry analysis. Moreover, ADSCs were efficient in preventing allograft rejection from the urinary bladder, as judged by biochemical, clinical and ultrasonography analysis. Together, these results compose characterization of protein expression profiles and immunosuppressive functionality of ADSCs in rabbits, which had undergone partial allografts of the urinary bladder, foreseeing future applications in clinical practice.

The effect of adipose-derived mesenchymal stem cells and chondrocytes with platelet-rich fibrin releasates augmentation by intra-articular injection on acute osteochondral defects in a rabbit model

BACKGROUND

This study aimed to investigate the efficacy of adipose-derived mesenchymal stem cells (ADSCs), platelet-rich fibrin releasates (PRFr), and chondrocyte transplantation in rabbit acute osteochondral defects.

METHODS

Thirty rabbits were randomly assigned to five groups: untreated controls; ADSCs alone; PRFr alone; PRFr + ADSCs; and PRFr + chondrocytes. The critical size osteochondral defects in right knee femoral condyles were injected intra-articularly according to the groups, as listed. The experimental rabbits received treatments once a week for two weeks postoperatively. All evaluations were conducted for 14 weeks following surgery, and the regenerated cartilages were assessed by gross inspection and histological examination.

RESULTS

There were no complications encountered in any of the rabbits. The size of the defect decreased and the volume of repaired cartilage increased in the medial femoral condyles of the PRFr + ADSCs group. Relative to the ADSCs or PRFr group, histological examination demonstrated that the PRFr + ADSCs group had thicker hyaline cartilage-specific extracellular matrix. Grading scores revealed that PRFr + ADSCs injection had better matrix, cell distribution, and surface indices than other groups (P < 0.05). However, the histological scores reported for PRFr + chondrocytes on cartilage repair were similar to those of PRFr, and there were no significant between-group differences.

CONCLUSIONS

These findings showed that intra-articular injections of PRFr + ADSCs into the knee can reduce cartilage defects by regenerating hyaline-like cartilage without complications. This approach may provide an alternative method for functional reconstruction of acute osteochondral defects with an unlimited source of cells and releasates.

Genetically Engineered Adipose Mesenchymal Stem Cells Using HIV-Based Lentiviral Vectors as Gene Therapy for Autoimmune Diseases

The immunomodulatory and self-renewable features of human adipose-derived mesenchymal stem cells (hAD-MSCs) mark their importance in regenerative medicine. Interleukin (IL)-23 as a proinflammatory cytokine suppresses T regulatory cells and promotes the response of T helper 17 and T helper 1 cells. This pathway initiates inflammation and immunosuppression in several autoimmune diseases. The current study aimed at producing recombinant IL-23 decoy receptor (RIL-23R) using hAD-MSCs as a good candidate for ex vivo cell-based gene therapy purposes to reduce inflammation in autoimmune diseases. hAD-MSCs was isolated from lipoaspirate and then characterized by differentiation. RIL-23R was designed and cloned into a pCDH813A-1 lentiviral vector. The transduction of hAD-MSCs was performed at multiplicity of infection = 50 with pCDH-EFI α-RIL-23R-PGK copGFP. Expressions of RIL-23R and octamer-binding transcription factor 4 (OCT-4) were determined by real-time polymerase chain reaction. Self-renewing properties were assayed with OCT-4. Bioactivity of the designed RIL-23R was evaluated by IL-17 and IL-10 expression of mouse splenocytes. The results showed that the transducted hAD-MSCs/RIL-23R, expressing IL-23 decoy receptor, can provide a useful approach for a basic research on cell-based gene therapy for autoimmune disorders.

Morpho-Functional Characteristics of Bone Marrow Multipotent Mesenchymal Stromal Cells after Activation or Inhibition of Epidermal Growth Factor and Toll-Like Receptors or Treatment with DNA Intercalator Cisplatin

This study is aimed to reveal morphological and functional changes in multipotent mesenchymal stromal cells (MSCs) isolated from the rat bone marrow after: (i) activation of Toll-like receptors (TLRs) with teichoic acid (TA), (ii) impact on epidermal growth factor (EGF) receptors with activator EGF or inhibitor Herceptin, and (iii) treatment with DNA intercalator Cisplatin. According to our results, TA and EGF cause an increase in the synthesis of glycosaminoglycans, c-Myc content, and protein in the MSC cytoplasm. It was observed that the cell population in G0 phase decreased and the cell population in G1 phase increased, when compared with control. At the same time, the cell population with a higher nuclear-cytoplasmic ratio (NCR) in S and G2 phases also increased. This indicates the manifestation of the MSC mesenchymal phenotype, exhibiting indirect metabolic signs of the regenerative potential increase. In other experiments, Herceptin was shown to suppress only the stemness signs of MSCs, while Cisplatin seriously affected cell viability in general, reducing synthetic and proliferative activities and causing cell morphology disturbances. © 2018 International Society for Advancement of Cytometry.

Pumpless Microflow Cytometry Enabled by Viscosity Modulation and Immunobead Labeling

Major challenges of miniaturizing flow cytometry include obviating the need for bulky, expensive, and complex pump-based fluidic and laser-based optical systems while retaining the ability to detect target cells based on their unique surface receptors. We addressed these critical challenges by (i) using a viscous liquid additive to control flow rate passively, without external pumping equipment, and (ii) adopting an immunobead assay that can be quantified with a portable fluorescence cell counter based on a blue light-emitting diode. Such novel features enable pumpless microflow cytometry (pFC) analysis by simply dropping a sample solution onto the inlet reservoir of a disposable cell-counting chamber. With our pFC platform, we achieved reliable cell counting over a dynamic range of 9-298 cells/μL. We demonstrated the practical utility of the platform by identifying a type of cancer cell based on CD326, the epithelial cell adhesion molecule. This portable microflow cytometry platform can be applied generally to a range of cell types using immunobeads labeled with specific antibodies, thus making it valuable for cell-based and point-of-care diagnostics.

Suxiao Jiuxin pill promotes exosome secretion from mouse cardiac mesenchymal stem cells in vitro

Cardiac mesenchymal stem cells (C-MSCs) are endogenous cardiac stromal cells that play a role in heart repair after injury. C-MSC-derived exosomes (Exo) have shown protective effects against apoptosis induced by acute myocardial ischemia/reperfusion. Suxiao Jiuxin pill (SJP) is a traditional Chinese medicine (TCM) formula used in China for the treatment of acute myocardial ischemia, which contains tetramethylpyrazine (TMP) and borneol (BOR) as major components. In this study, we investigated whether SJP treatment affected exosome release from C-MSCs in vitro. C-MSCs prepared from mice were treated with SJP (62.5 μg/mL), TMP (25 μg/mL) or BOR (15 μg/mL). Using an acetylcholinesterase activity assay, we found that both SJP and TMP treatment significantly increased exosome secretion compared to the control ethanol treatment. The neutral sphingomyelinase 2 (nSMase2) pathway was important in exosome formation and packaging. But neither the level of nSMase2 mRNA nor the level of protein changed following SJP, TMP or BOR treatment, suggesting that SJP stimulated exosome release via an nSMase2-independent pathway. The Rab27a and Rab27b GTPases controlled different steps of the exosome secretion pathway. We showed that SJP treatment significantly increased the protein levels of Rab27a, SYTL4 (Rab27a effector) and Rab27b compared with the control treatment. SJP treatment also significantly upregulated the mRNA level of Rab27b, rather than Rab27a. Moreover, SJP-induced increase of C-MSC-exosome release was inhibited by Rab27b knockdown, suggesting that SJP promotes exosome secretion from C-MSCs via a GTPase-dependent pathway. This study reveals a novel mechanism for SJP in modulating cardiac homeostasis.

Editor's Highlight: Thy1 (CD90) Expression is Reduced by the Environmental Chemical Tetrabromobisphenol-A to Promote Adipogenesis Through Induction of microRNA-103

Environmental chemicals termed "obesogens" disrupt the endocrine system to promote adipogenesis and obesity. Tetrabromobisphenol-A (TBBPA) has been reported to increase adipogenesis; however, the mechanism(s) of action are unclear. Thy1 (CD90) is a glycophosphatidylinositol-anchored membrane protein that serves as a marker for stem cells and also plays an important role in regulating adipogenesis and obesity. We investigated whether or not TBBPA promotes adipogenesis in human and mouse cells by reducing Thy1 levels. We further sought to identify the molecular mechanism(s) whereby TBBPA targets Thy1 expression. Mouse and human cells were exposed to TBBPA, and Thy1 expression was analyzed using flow cytometry, Western blotting, and qPCR. We tested whether microRNAs predicted to target Thy1 (miR-103 and miR-107) were upregulated by TBBPA using quantitative PCR assays. We also determined if Thy1 mRNA was a bona fide miR-103/107 target. Our results show that Thy1 expression was reduced in both human and mouse cells after exposure to TBBPA. Both Thy1 mRNA and protein levels were decreased by low-dose TBBPA exposure. TBBPA reduced Thy1 levels and further increased adipogenesis when an adipogenic medium was used. Mechanistically, we show that miR-103 and miR-107 are induced by TBBPA and that miR-103 targets Thy1 to reduce its expression. Our results reveal for the first time that Thy1 is a target of TBBPA. Furthermore, our data support the concept that Thy1 is a key marker targeted by environmental chemicals that promote adipogenesis and obesity.

Bone marrow-derived mesenchymal stem cells versus adipose-derived mesenchymal stem cells for peripheral nerve regeneration

Studies have confirmed that bone marrow-derived mesenchymal stem cells (MSCs) can be used for treatment of several nervous system diseases. However, isolation of bone marrow-derived MSCs (BMSCs) is an invasive and painful process and the yield is very low. Therefore, there is a need to search for other alterative stem cell sources. Adipose-derived MSCs (ADSCs) have phenotypic and gene expression profiles similar to those of BMSCs. The production of ADSCs is greater than that of BMSCs, and ADSCs proliferate faster than BMSCs. To compare the effects of venous grafts containing BMSCs or ADSCs on sciatic nerve injury, in this study, rats were randomly divided into four groups: sham (only sciatic nerve exposed), Matrigel (MG; sciatic nerve injury + intravenous transplantation of MG vehicle), ADSCs (sciatic nerve injury + intravenous MG containing ADSCs), and BMSCs (sciatic nerve injury + intravenous MG containing BMSCs) groups. Sciatic functional index was calculated to evaluate the function of injured sciatic nerve. Morphologic characteristics of nerves distal to the lesion were observed by toluidine blue staining. Spinal motor neurons labeled with Fluoro-Gold were quantitatively assessed. Compared with sham-operated rats, sciatic functional index was lower, the density of small-diameter fibers was significantly increased, and the number of motor neurons significantly decreased in rats with sciatic nerve injury. Neither ADSCs nor BMSCs significantly improved the sciatic nerve function of rats with sciatic nerve injury, increased fiber density, fiber diameters, axonal diameters, myelin sheath thickness, and G ratios (axonal diameter/fiber diameter ratios) in the sciatic nerve distal to the lesion site. There was no significant difference in the number of spinal motor neurons among ADSCs, BMSCs and MG groups. These results suggest that neither BMSCs nor ADSCs provide satisfactory results for peripheral nerve repair when using MG as the conductor for engraftment.

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

Mesenchymal stem cells (MSC) hold great potential for regenerative medicine because of their ability for self-renewal and differentiation into tissue-specific cells such as osteoblasts, chondrocytes, and adipocytes. MSCs orchestrate tissue development, maintenance and repair, and are useful for musculoskeletal regenerative therapies to treat age-related orthopedic degenerative diseases and other clinical conditions. Importantly, MSCs produce secretory factors that play critical roles in tissue repair that support both engraftment and trophic functions (autocrine and paracrine). The development of uniform protocols for both preparation and characterization of MSCs, including standardized functional assays for evaluation of their biological potential, are critical factors contributing to their clinical utility. Quality control and release criteria for MSCs should include cell surface markers, differentiation potential, and other essential cell parameters. For example, cell surface marker profiles (surfactome), bone-forming capacities in ectopic and orthotopic models, as well as cell size and granularity, telomere length, senescence status, trophic factor secretion (secretome), and immunomodulation, should be thoroughly assessed to predict MSC utility for regenerative medicine. We propose that these and other functionalities of MSCs should be characterized prior to use in clinical applications as part of comprehensive and uniform guidelines and release criteria for their clinical-grade production to achieve predictably favorable treatment outcomes for stem cell therapy. Stem Cells Translational Medicine 2017;6:2173-2185.

A novel cytotherapy device for rapid screening, enriching and combining mesenchymal stem cells into a biomaterial for promoting bone regeneration

Bone defects are a common challenge in clinic, usually warranting bone grafts. However, current strategies to obtain effective graft materials have many drawbacks. Mesenchymal stem cell (MSC)-based therapy is a promising alternative. We designed an innovative appliance named the stem cell screen-enrich-combine(-biomaterials) circulating system (SECCS). In this study, 42 patients who required bone graft underwent SECCS-based treatment. Their bone marrow samples and beta-tricalcium phosphate (β-TCP) granules were processed in the SECCS for 10-15 minutes, to produce MSC/β-TCP composites. These composites were grafted back into bone defect sites. The results showed 85.53% ± 7.95% autologous MSCs were successfully screened, enriched, and seeded on the β-TCP scaffolds synchronously. The cell viability remained unchanged after SECCS processing. Clinically, all patients obtained satisfactory bone healing. Thus, without in vitro culture, the SECCS can produce bioactive MSC/β-TCP composites for bone regeneration during surgery. The SECCS represents a convenient, rapid, low-cost, and safe method for bone regeneration.