Cell and gene therapy using mesenchymal stem cells (MSCs)

Oncolytic virus-based hepatocellular carcinoma treatment: Current status, intravenous delivery strategies, and emerging combination therapeutic solutions

Current treatments for advanced hepatocellular carcinoma (HCC) have limited success in improving patients' quality of life and prolonging life expectancy. The clinical need for more efficient and safe therapies has contributed to the exploration of emerging strategies. Recently, there has been increased interest in oncolytic viruses (OVs) as a therapeutic modality for HCC. OVs undergo selective replication in cancerous tissues and kill tumor cells. Strikingly, pexastimogene devacirepvec (Pexa-Vec) was granted an orphan drug status in HCC by the U.S. Food and Drug Administration (FDA) in 2013. Meanwhile, dozens of OVs are being tested in HCC-directed clinical and preclinical trials. In this review, the pathogenesis and current therapies of HCC are outlined. Next, we summarize multiple OVs as single therapeutic agents for the treatment of HCC, which have demonstrated certain efficacy and low toxicity. Emerging carrier cell-, bioengineered cell mimetic- or nonbiological vehicle-mediated OV intravenous delivery systems in HCC therapy are described. In addition, we highlight the combination treatments between oncolytic virotherapy and other modalities. Finally, the clinical challenges and prospects of OV-based biotherapy are discussed, with the aim of continuing to develop a fascinating approach in HCC patients.

Transplantation of human adipose-derived stem cells overexpressing LIF/IFN-β promotes recovery in experimental autoimmune encephalomyelitis (EAE)

Multiple Sclerosis (MS) is the most common demyelinating disease with inflammatory demyelination in the central nerve system. Besides the defect in the myelin repair process, the balance change in inflammatory and anti- inflammatory cytokines is one of the most significant factors in MS pathogenesis. This study aimed at evaluating the effects of co-overexpressing beta interferon (IFN-β) and Leukemia inhibitory factor (LIF) in human adipose-derived stem cells (IFN-β/LIF-hADSCs) on the experimental autoimmune encephalomyelitis (EAE). 12 days after the induction of EAE on female mice C57Bl/6 with MOG35-55 and the emergence of primary clinical signs, the IFN-β/LIF-hADSCs were injected into the mice tail vein of the EAE mice. The mice were sacrificed after 32 days and the spinal cords of the experimental groups were dissected out for the histopathologic and real-time RT-PCR studies. Here, we showed that the clinical scores and infiltration of mononuclear cells of treated mice with IFN-β/LIF-hADSCs were decreased significantly. Demyelination and the number of Olig2⁺ and MBP⁺ cells were significantly increased in the test (IFN-β/LIF-hADSCs) group. The findings revealed that the pattern of inflammatory and anti- inflammatory cytokines gene expression in the IFN-β/LIF-hADSCs group was reversed compared to the control group. Overexpression of LIF as a neurotrophic and IFN-β as an anti-inflammatory cytokine in hADSCs increases the immunomodulatory effect of hADSCs reduces the extent of demyelination, improves the number of Olig2⁺ cells, and also increases the amount of MBP protein which can increase the production of myelin in EAE model. This, besides hADSCs capacity for proliferation and differentiation, might enhance the treatment efficacy and provide a promising candidate for stem cell-based gene therapy of MS therapy in the future.

Dental-Pulp Stem Cells as a Therapeutic Strategy for Ischemic Stroke

Regenerative medicine aims to restore human functions by regenerating organs and tissues using stem cells or living tissues for the treatment of organ and tissue defects or dysfunction. Clinical trials investigating the treatment of cerebral infarction using mesenchymal stem cells, a type of somatic stem cell therapy, are underway. The development and production of regenerative medicines using somatic stem cells is expected to contribute to the treatment of cerebral infarction, a central nervous system disease for which there is no effective treatment. Numerous experimental studies have shown that cellular therapy, including the use of human dental pulp stem cells, is an attractive strategy for patients with ischemic brain injury. This review describes the basic research, therapeutic mechanism, clinical trials, and future prospects for dental pulp stem cell therapy, which is being investigated in Japan in first-in-human clinical trials for the treatment of patients with acute cerebral ischemia.

Post-decellularization techniques ameliorate cartilage decellularization process for tissue engineering applications

Due to the current lack of innovative and effective therapeutic approaches, tissue engineering (TE) has attracted much attention during the last decades providing new hopes for the treatment of several degenerative disorders. Tissue engineering is a complex procedure, which includes processes of decellularization and recellularization of biological tissues or functionalization of artificial scaffolds by active cells. In this review, we have first discussed those conventional steps, which have led to great advancements during the last several years. Moreover, we have paid special attention to the new methods of post-decellularization that can significantly ameliorate the efficiency of decellularized cartilage extracellular matrix (ECM) for the treatment of osteoarthritis (OA). We propose a series of post-decellularization procedures to overcome the current shortcomings such as low mechanical strength and poor bioactivity to improve decellularized ECM scaffold towards much more efficient and higher integration.

Tracking mesenchymal stem cells with Ir(III) complex-encapsulated nanospheres in cranium defect with postmenopausal osteoporosis

Osteoporosis (OP) is a significant public health problem with associated fragility fractures, thereby causing large bone defects and difficulty in self-repair. The introduction of human mesenchymal stem cells (hMSCs) is the most promising platform in bone tissue engineering for OP therapy, which induces less side effects than conventional medication. However, the safety and efficiency of the cell-based OP therapy requires the ability to monitor the cell's outcome and biodistribution after cell transplantation. Therefore, we designed an in vivo system to track hMSCs in real time and simultaneously attempted to obtain a significant therapeutic effect during the bone repair process. In this study, we synthesized Ir(III) complex, followed by encapsulation with biodegradable methoxy-poly(ethylene glycol) poly(lactic-co-glycolic acid) nanospheres through double emulsions strategy. The Ir(III) complex nanospheres did not affect hMSC proliferation, stemness, and differentiation and realized highly efficient and long-term cellular labeling for at least 25 days in vivo. The optimal transplantation conditions were also determined first by injecting a gradient number of labeled hMSCs percutaneously into the cranial defect of the nude mouse model. Next, we applied this method to ovariectomy-induced OP mice. Results showed long-term optical imaging with high fluorescence intensity and computed tomography (CT) scanning with significantly increased bone formation between the osteoporotic and sham-operated bones. During the tracking process, two mice from each group were sacrificed at two representative time points to examine the bony defect bridging via micro-CT morphometric analyses. Our data showed remarkable promise for efficient hMSC tracking and encouraging treatment in bioimaging-guided OP stem cell therapy.

Regulation of bone marrow mesenchymal stem cell fate by long non-coding RNA

Bone mesenchymal stem cells (BMSCs) are progenitor cells isolated from bone marrow, which keep potential to differentiate into several kinds of cells including osteoblasts and adipocytes. A dynamic mutual regulation exists between osteogenesis and adipogenesis processes. Long non-coding RNA (lncRNA) performs diverse functions in biological activities including regulation of BMSCs commitment. Evidence has shown that lncRNA regulates key signaling pathways including TGFβ/BMP, Wnt and Notch pathways, and several transcription factors in BMSCs differention. Dysregulation of lncRNA in BMSCs leads to disruption of osteo-adipogenesis difffrentiation and results in impairment of bone homeostasis. In this review, we focus on the role of lncRNA in several critical signaling pathways that involved in regulation of osteo-adipogenesis of BMSC and prospects the potential clinical application of lncRNA.

Primary Ciliary Signaling in the Skin-Contribution to Wound Healing and Scarring

Primary cilia (PC) are solitary, post-mitotic, microtubule-based, and membrane-covered protrusions that are found on almost every mammalian cell. PC are specialized cellular sensory organelles that transmit environmental information to the cell. Signaling through PC is involved in the regulation of a variety of cellular processes, including proliferation, differentiation, and migration. Conversely, defective, or abnormal PC signaling can contribute to the development of various pathological conditions. Our knowledge of the role of PC in organ development and function is largely based on ciliopathies, a family of genetic disorders with mutations affecting the structure and function of PC. In this review, we focus on the role of PC in their major signaling pathways active in skin cells, and their contribution to wound healing and scarring. To provide comprehensive insights into the current understanding of PC functions, we have collected data available in the literature, including evidence across cell types, tissues, and animal species. We conclude that PC are underappreciated subcellular organelles that significantly contribute to both physiological and pathological processes of the skin development and wound healing. Thus, PC assembly and disassembly and PC signaling may serve as attractive targets for antifibrotic and antiscarring therapies.

Challenges of stem cell therapies in companion animal practice

Regenerative medicine using stem cells from various sources are emerging treatment modality in several refractory diseases in veterinary medicine. It is well-known that stem cells can differentiate into specific cell types, self-renew, and regenerate. In addition, the unique immunomodulatory effects of stem cells have made stem cell transplantation a promising option for treating a wide range of disease and injuries. Recently, the medical demands for companion animals have been rapidly increasing, and certain disease conditions require alternative treatment options. In this review, we focused on stem cell application research in companion animals including experimental models, case reports and clinical trials in dogs and cats. The clinical studies and therapeutic protocols were categorized, evaluated and summarized according to the organ systems involved. The results indicate that evidence for the effectiveness of cell-based treatment in specific diseases or organ systems is not yet conclusive. Nonetheless, stem cell therapy may be a realistic treatment option in the near future, therefore, considerable efforts are needed to find optimized cell sources, cell numbers and delivery methods in order to standardize treatment methods and evaluation processes.

Strategies for treating oesophageal diseases with stem cells

There is a wide range of oesophageal diseases, the most general of which are inflammation, injury and tumours, and treatment methods are constantly being developed and updated. With an increasingly comprehensive understanding of stem cells and their characteristics of multilineage differentiation, self-renewal and homing as well as the combination of stem cells with regenerative medicine, tissue engineering and gene therapy, stem cells are playing an important role in the treatment of a variety of diseases. Mesenchymal stem cells have many advantages and are most commonly applied; however, most of these applications have been in experimental studies, with few related clinical trials for comparison. Therefore, the methods, positive significance and limitations of stem cells in the treatment of oesophageal diseases remain incompletely understood. Thus, the purpose of this paper is to review the current literature and summarize the efficacy of stem cells in the treatment of oesophageal diseases, including oesophageal ulceration, acute radiation-induced oesophageal injury, corrosive oesophageal injury, oesophageal stricture formation after endoscopic submucosal dissection and oesophageal reconstruction, as well as gene therapy for oesophageal cancer.

Therapeutic Mesenchymal Stromal Cells for Immunotherapy and for Gene and Drug Delivery

Mesenchymal stromal cells (MSCs) possess several fairly unique properties that, when combined, make them ideally suited for cellular-based immunotherapy and as vehicles for gene and drug delivery for a wide range of diseases and disorders. Key among these are: (1) their relative ease of isolation from a variety of tissues; (2) the ability to be expanded in culture without a loss of functionality, a property that varies to some degree with tissue source; (3) they are relatively immune-inert, perhaps obviating the need for precise donor/recipient matching; (4) they possess potent immunomodulatory functions that can be tailored by so-called licensing in vitro and in vivo; (5) the efficiency with which they can be modified with viral-based vectors; and (6) their almost uncanny ability to selectively home to damaged tissues, tumors, and metastases following systemic administration. In this review, we summarize the latest research in the immunological properties of MSCs, their use as immunomodulatory/anti-inflammatory agents, methods for licensing MSCs to customize their immunological profile, and their use as vehicles for transferring both therapeutic genes in genetic disease and drugs and genes designed to destroy tumor cells.

Therapeutic effect against retinal neovascularization in a mouse model of oxygen-induced retinopathy: bone marrow-derived mesenchymal stem cells versus Conbercept

BACKGROUND

To study the therapeutic effect of bone marrow-derived mesenchymal stem cells (BMSC) against retinal neovascularization and to compare with anti-vascular endothelial growth factor (VEGF) therapy.

METHODS

Neonatal C57BL/6 mice were exposed in hyperoxygen and returned to room air to develop oxygen-induced retinopathy (OIR). Red fluorescent protein-labeled BMSC and Conbercept were intravitreally injected into OIR mice, respectively. Inhibition of neovascularization and apoptosis in OIR mice were assessed through retinal angiography, histopathology and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.

RESULTS

BMSC were able to migrate and integrate into the host retina, significantly inhibit retinal neovascular tufts and remodel the capillary network after injecton. Treatment with BMSC increased the retinal vascular density, decreased the number of acellular capillaries and inhibited retinal cell death. This effect was not inferior to current anti-VEGF therapy by using Conbercept.

CONCLUSIONS

Intravitreal injection of BMSC exerts a protective effect against retinal neovascularization and offers a therapeutic strategy for oxygen-induced retinopathy.

MSC-Derived Exosomes-Based Therapy for Peripheral Nerve Injury: A Novel Therapeutic Strategy

Although significant advances have been made in synthetic nerve conduits and surgical techniques, complete regeneration following peripheral nerve injury (PNI) remains far from optimized. The repair of PNI is a highly heterogeneous process involving changes in Schwann cell phenotypes, the activation of macrophages, and the reconstruction of the vascular network. At present, the efficacy of MSC-based therapeutic strategies for PNI can be attributed to paracrine secretion. Exosomes, as a product of paracrine secretion, are considered to be an important regulatory mediator. Furthermore, accumulating evidence has demonstrated that exosomes from mesenchymal stem cells (MSCs) can shuttle bioactive components (proteins, lipids, mRNA, miRNA, lncRNA, circRNA, and DNA) that participate in almost all of the abovementioned processes. Thus, MSC exosomes may represent a novel therapeutic tool for PNI. In this review, we discuss the current understanding of MSC exosomes related to peripheral nerve repair and provide insights for developing a cell-free MSC therapeutic strategy for PNI.

Transplantation of dental pulp-derived cell sheets cultured on human amniotic membrane induced to differentiate into bone

OBJECTIVE

The usefulness of the amniotic membrane as a cell culture substrate has led to its use in the development of dental pulp-derived cell sheets. We induced osteoblastic differentiation of dental pulp-derived cell sheets and conducted histological and immunological examinations in addition to imaging assessments for regeneration of bone defects.

METHODS

Dental pulp cells were obtained by primary culture of the dental pulp tissue harvested from extracted wisdom teeth. These cells were maintained for three to four passages. Subsequently, the dental pulp cells were seeded onto an amniotic membrane to produce dental pulp-derived cell sheets. Following the induction of osteoblastic differentiation, the sheets were grafted into the subcutaneous tissue of the lower back and maxillary bone defect of a nude mouse. Histological and immunological examinations of both grafts were performed.

RESULTS

Dental pulp-derived cell sheets cultured on an osteoblast differentiation-inducing medium demonstrated resemblance to dental pulp tissue and produced calcified tissue. Mineralization was maintained following grafting of the sheets. Regeneration of the maxillary bone defect was observed.

CONCLUSION

Induction of osteoblastic differentiation of the dental pulp-derived cell sheets may be indicated for the regeneration of periodontal tissue.

Engineered human mesenchymal stem cells for neuroblastoma therapeutics

Drug-resistant neuroblastoma remains a major challenge in paediatric oncology and novel and less toxic therapeutic approaches are urgently needed to improve survival and reduce the side effects of traditional therapeutic interventions. Mesenchymal stem cells (MSCs) are an attractive candidate for cell and gene therapy since they are recruited by and able to infiltrate tumours. This feature has been exploited by creating genetically modified MSCs that are able to combat cancer by delivering therapeutic molecules. Whether neuroblastomas attract systemically delivered MSCs is still controversial. We investigated whether MSCs engineered to express tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) could: i) cause death of classic and primary neuroblastoma cell lines in vitro; ii) migrate to tumour sites in vivo; and iii) reduce neuroblastoma growth in xenotransplantation experiments. We observed that classic and primary neuroblastoma cell lines expressing death receptors could be killed by TRAIL-loaded MSCs in vitro. When injected in the peritoneum of neuroblastoma-bearing mice, TRAIL-MSCs migrated to tumour sites, but were unable to change the course of cancer development. These results indicated that MSCs have the potential to be used to deliver drugs in neuroblastoma patients, but more effective biopharmaceuticals should be used instead of TRAIL.

Gold nanoparticle coatings as efficient adenovirus carriers to non-infectable stem cells

Mesenchymal stem cells (MSCs) are adult pluripotent cells with the plasticity to be converted into different cell types. Their self-renewal capacity, relative ease of isolation, expansion and inherent migration to tumors, make them perfect candidates for cell therapy against cancer. However, MSCs are notoriously refractory to adenoviral infection, mainly because CAR (Coxsackie-Adenovirus Receptor) expression is absent or downregulated. Over the last years, nanoparticles have attracted a great deal of attention as potential vehicle candidates for gene delivery, but with limited effects on their own. Our data showed that the use of positively charged 14 nm gold nanoparticles either functionalized with arginine-glycine-aspartate (RGD) motif or not, increases the efficiency of adenovirus infection in comparison to commercial reagents without altering cell viability or cell phenotype. This system represents a simple, efficient and safe method for the transduction of MSCs, being attractive for cancer gene and cell therapies.

Immunomodulatory effects of mesenchymal stem cell-derived exosomes on experimental type-1 autoimmune diabetes

Exosomes derived from adipose tissue-derived mesenchymal stem cells (AD-MSCs) have immunomodulatory effects of T-cell inflammatory response and reduction of clinical symptoms on streptozotocin-induced of the type-1 diabetes mellitus (T1DM). Beside control group and untreated T1DM mice, a group of T1DM mice was treated with intraperitoneal injections of characterized exosomes derived from autologous AD-MSCs. Body weight and blood glucose levels were measured during the procedure. Histopathology and immunohistochemistry were used for evaluation of pancreatic islets using hemotoxylin and eosin (H&E) staining and anti-insulin antibody. Isolated splenic mononuclear cells (MNCs) were subjected to splenocytes proliferation assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, immunophenotyping of regulatory T cells and cytokines. A significant increase in the levels of interleukin-4 (IL-4), IL-10, and transforming growth factor-β, and a decrease in the levels of IL-17 and interferon-γ in concordance with the significant increase in the Treg cell ratio in splenic MNCs (P < 0.05) was shown in T1DM mice treated with AD-MSC's exosomes as compared to T1DM untreated mice. This amelioration of autoimmune reaction after treatment of T1DM mice with the AD-MSC exosomes was confirmed with a significant increase in islets using H&E staining and Immunohistochemistry analyses. As expected, body weight, blood glucose levels in a survival of T1DM mice treated with AD-MSC's exosomes were maintained stable in comparison to untreated T1DM mice. It can be concluded that AD-MSC's exosomes exert ameliorative effects on autoimmune T1DM through increasing regulatory T-cell population and their products without a change in the proliferation index of lymphocytes, which makes them more effective and practical candidates.

Targeted intracerebral delivery of the anti-inflammatory cytokine IL13 promotes alternative activation of both microglia and macrophages after stroke

Background

Subtle adjustment of the activation status of CNS resident microglia and peripheral macrophages, to promote their neuroprotective and neuroregenerative functions, may facilitate research towards curing neurodegenerative disorders. In the present study, we investigated whether targeted intracerebral delivery of the anti-inflammatory cytokine interleukin (IL)13, by means of transplanting IL13-expressing mesenchymal stem cells (IL13-MSCs), can promote a phenotypic switch in both microglia and macrophages during the pro-inflammatory phase in a mouse model of ischemic stroke.

Methods

We used the CX₃CR1^eGFP/+ CCR2^RFP/+ transgenic mouse model to separately recognize brain-resident microglia from infiltrated macrophages. Quantitative immunohistochemical analyses were applied to characterize polarization phenotypes of both cell types.

Results

Distinct behaviors of both cell populations were noted dependent on the anatomical site of the lesion. Immunohistochemistry revealed that mice grafted with IL13-MSCs, in contrast to non-grafted and MSC-grafted control mice, were able to drive recruited microglia and macrophages into an alternative activation state, as visualized by a significant increase of Arg-1 and a noticeable decrease of MHC-II expression at day 14 after ischemic stroke. Interestingly, both Arg-1 and MHC-II were expressed more abundantly in macrophages than in microglia, further confirming the distinct behavior of both cell populations.

Conclusions

The current data highlight the importance of controlled and localized delivery of the anti-inflammatory cytokine IL13 for modulation of both microglia and macrophage responses after ischemic stroke, thereby providing pre-clinical rationale for the application of L13-MSCs in future investigations of neurodegenerative disorders.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1212-7) contains supplementary material, which is available to authorized users.

Supramolecular hydrogels encapsulating bioengineered mesenchymal stem cells for ischemic therapy

We developed supramolecular hyaluronate (HA) hydrogels to encapsulate genetically engineered mesenchymal stem cells (MSCs) for the treatment of limb ischemia. In vivo angiogenic factors could be produced stably by the bioengineered MSCs (BMSCs) within the supramolecular hydrogels showing effective vascular repair and enhanced blood perfusion.

E1A-engineered human umbilical cord mesenchymal stem cells as carriers and amplifiers for adenovirus suppress hepatocarcinoma in mice

Gene therapy is an attractive approach for hepatocellular carcinoma (HCC) patients. Nevertheless, efficient transgene delivery remains a challenge. In this study, we explored a new targeted system based on human umbilical cord-derived mesenchymal stem cells (HUMSCs), which were engineered to deliver adenovirus to tumor sites, and to replicate and assemble into new adenovirus against HCC. Our results showed that HUMSCs infected by Ad-hTERTp-IL24 followed by LentiR.E1A infection could specifically migrate to HepG2 tumor cells and support adenoviral replication in vitro and in vivo 36 h after LentiR.E1A infection. Ad-hTERTp-IL24 specifically inhibited HepG2 cells growth, and this inhibitory effect was enhanced by low doses of 5-fluorouracil (5-Fu), because the expression levels of coxsackie adenovirus receptor (CAR) and integrin ανβ3 on tumor cells were significantly increased, causing higher viral uptake. Compared with the no treatment groups, Ad-hTERTp-IL24 and LentiR.E1A co-loaded HUMSCs exhibited significant anti-tumor activity in vivo, particularly in combination with low doses of 5-Fu. In summary, this study provides a promising targeted gene therapeutic strategy dependent on the tumor tropism of HUMSCs, to improve the outcome of virotherapy for tumor patients especially those with metastatic diseases.

Possibility of inhibiting arthritis and joint destruction by SSEA-3 positive cells derived from synovial tissue in rheumatoid arthritis

Aim

Joint destruction progresses irreversibly once they occur in rheumatoid arthritis (RA), even with the recent development of anti-rheumatic drugs. Cells positive for stage-specific embryonic antigen-3 (SSEA-3), a marker of human embryonic stem cell, act as stem cells in the blood. The aim of this study is to investigate the effectiveness of SSEA-3 positive cells for the treatment for RA.

Methods

Synovial tissues were harvested at the time of joint surgery in RA patients. Cultured synovial cells were sorted by anti-SSEA-3 antibody using flow cytometry and were analyzed in in vitro. To investigate inhibitory effects on arthritis by SSEA-3 positive cells, collagen antibody-induced arthritis (CAIA) mice were used and transplanted with labeled cells intravenously.

Results

Presence of SSEA-3 positive cells was confirmed with approximately 1% in RA synovial cells. SSEA-3 positive cells were negative for CD34 and positive for CD44, CD90 and CD105. Multipotency of SSEA-3 positive cells was higher than that of SSEA-3 negative cells. Arthritis of the group transplanted with SSEA-3 positive cells in CAIA mice decreased over time.

Conclusions

SSEA-3 positive cells derived from RA synovial tissue might have the inhibitory effect on arthritis and would be one of cell source for new RA treatment.

The Challenge in Using Mesenchymal Stromal Cells for Recellularization of Decellularized Cartilage

Some decellularized musculoskeletal extracellular matrices (ECM)s derived from tissues such as bone, tendon and fibrocartilaginous meniscus have already been clinical use for tissue reconstruction. Repair of articular cartilage with its unique zonal ECM architecture and composition is still an unsolved problem, and the question is whether allogenic or xenogeneic decellularized cartilage ECM could serve as a biomimetic scaffold for this purpose.Hence, this survey outlines the present state of preparing decellularized cartilage ECM-derived scaffolds or composites for reconstruction of different cartilage types and of reseeding it particularly with mesenchymal stromal cells (MSCs).The preparation of natural decellularized cartilage ECM scaffolds hampers from the high density of the cartilage ECM and lacking interconnectivity of the rather small natural pores within it: the chondrocytes lacunae. Nevertheless, the reseeding of decellularized ECM scaffolds before implantation provided superior results compared with simply implanting cell-free constructs in several other tissues, but cartilage recellularization remains still challenging. Induced by cartilage ECM-derived scaffolds MSCs underwent chondrogenesis.Major problems to be addressed for the application of cell-free cartilage were discussed such as to maintain ECM structure, natural chemistry, biomechanics and to achieve a homogenous and stable cell recolonization, promote chondrogenic and prevent terminal differentiation (hypertrophy) and induce the deposition of a novel functional ECM. Some promising approaches were proposed including further processing of the decellularized ECM before recellularization of the ECM with MSCs, co-culturing of MSCs with chondrocytes and establishing bioreactor culture e.g. with mechanostimulation, flow perfusion pressure and lowered oxygen tension. Graphical Abstract Synopsis of tissue engineering approaches based on cartilage-derived ECM.

The Role of Integrin α6 (CD49f) in Stem Cells: More than a Conserved Biomarker

Stem cells have the capacity for self-renewal and differentiation into specialized cells that form and repopulated all tissues and organs, from conception to adult life. Depending on their capacity for differentiation, stem cells are classified as totipotent (ie, zygote), pluripotent (ie, embryonic stem cells), multipotent (ie, neuronal stem cells, hematopoietic stem cells, epithelial stem cells, etc.), and unipotent (ie, spermatogonial stem cells). Adult or tissue-specific stem cells reside in specific niches located in, or nearby, their organ or tissue of origin. There, they have microenvironmental support to remain quiescent, to proliferate as undifferentiated cells (self-renewal), and to differentiate into progenitors or terminally differentiated cells that migrate from the niche to perform specialized functions. The presence of proteins at the cell surface is often used to identify, classify, and isolate stem cells. Among the diverse groups of cell surface proteins used for these purposes, integrin α6, also known as CD49f, may be the only biomarker commonly found in more than 30 different populations of stem cells, including some cancer stem cells. This broad expression among stem cell populations indicates that integrin α6 may play an important and conserved role in stem cell biology, which is reaffirmed by recent demonstrations of its role maintaining self-renewal of pluripotent stem cells and breast and glioblastoma cancer stem cells. Therefore, this review intends to highlight and synthesize new findings on the importance of integrin α6 in stem cell biology.

Characterization of the Tumor Microenvironment and Tumor-Stroma Interaction by Non-invasive Preclinical Imaging

Tumors are often characterized by hypoxia, vascular abnormalities, low extracellular pH, increased interstitial fluid pressure, altered choline-phospholipid metabolism, and aerobic glycolysis (Warburg effect). The impact of these tumor characteristics has been investigated extensively in the context of tumor development, progression, and treatment response, resulting in a number of non-invasive imaging biomarkers. More recent evidence suggests that cancer cells undergo metabolic reprograming, beyond aerobic glycolysis, in the course of tumor development and progression. The resulting altered metabolic content in tumors has the ability to affect cell signaling and block cellular differentiation. Additional emerging evidence reveals that the interaction between tumor and stroma cells can alter tumor metabolism (leading to metabolic reprograming) as well as tumor growth and vascular features. This review will summarize previous and current preclinical, non-invasive, multimodal imaging efforts to characterize the tumor microenvironment, including its stromal components and understand tumor-stroma interaction in cancer development, progression, and treatment response.

Effects of herbal Epimedium on the improvement of bone metabolic disorder through the induction of osteogenic differentiation from bone marrow-derived mesenchymal stem cells

Herbal Epimedium (HE) has been commonly used as a tonic, antirheumatic agent and in the treatment of bone-associated diseases including osteoporosis. Treatment for osteoporosis is important to increase bone mass density and maintain to balance of bone remodeling. The present study was performed to investigate the effects of HE on mouse bone marrow mesenchymal stem cell (mBMMSC) proliferation and osteogenic differentiation, using MTT assays, proliferating cell nuclear antigen (PCNA) detection and apoptosis and differentiation assays. HE was demonstrated to inhibit the proliferation of mBMMSCs up to 45.43±3.33% and to decrease the level of PCNA expression compared with untreated cells. HE also induced late apoptosis at 24 and 48 h after treatment up to 71.93 and 67.03%, respectively, while only 14.93% of untreated cells exhibited apoptosis. By contrast, HE induced differentiation of mBMMSCs into an osteogenic lineage at the beginning of three weeks after commencement of treatment. This suggested that HE is a candidate as an inducer of osteogenesis from bone marrow mesenchymal stem cells, and additionally has potential for use in the treatment of bone metabolic disorders such as osteoporosis.

Mesenchymal stem cells overexpressing IL-35 effectively inhibit CD4+ T cell function

Mesenchymal stem cells (MSCs) have recently emerged as promising candidates for cell-based immune tolerance therapy. Interleukin 35 (IL-35) is a relatively newly identified cytokine required for the regulatory and suppressive functions of regulatory T cells (Treg), playing an important role in the prevention of autoimmune diseases. In this study, we isolated adipose tissue-derived MSCs, a good vehicle for cell therapy, which were transfected with a lentivirus vector for the overexpression of the therapeutic murine IL-35 gene. IL-35 levels in transfected MSCs (IL-35-MSCs) were quantified by ELISA. Co-culture of CD4⁺ T cells and IL-35-MSCs resulted in the inhibition of CD4⁺ T cell proliferation and IL-17A secretion. In addition, IL-35-MSCs induced IL-10 production by CD4⁺ T cells, but did not affect IFN-γ. These findings suggested that MSCs over-expressing IL-35 had higher immunosuppressive capacity compared with non-transfected MSCs, and may provide a useful approach for basic research on gene therapy for autoimmune disorders.

High expression of heme oxygenase-1 in target organs may attenuate acute graft-versus-host disease through regulation of immune balance of TH17/Treg

The high incidence of acute graft-versus-host disease (aGVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Grades III and IV aGVHD are the leading causes of death in allo-HSCT recipients. Heme oxygenase-1(HO-1) has anti-inflammatory and immune-regulatory functions. In this study, we evaluated the none GVHD and grade I-IV patients samples which were collected at the first re-examination after successful allo-HSCT, we found that expressions of HO-1 mRNA in the bone marrow and peripheral blood mononuclear cells of allo-HSCT recipients who had subsequent non-GVHD and grade I aGVHD were significantly higher than those in patients with Grade III-IV aGVHD. We then demonstrated that enhanced expression of HO-1 in target organs by infusing HO-1-gene-modified Mesenchymal stem cells (MSCs) alleviated the clinical and histopathological severity of aGVHD in experimental mice. Flow cytometry revealed a higher expression of Treg cells and a lower expression of TH17 cells in splenic and lymph node tissues of mice with enhanced HO-1 expression, as compared to that in the aGVHD mice. This was further substantiated by lower expression levels of ROR-Υt and IL-17A mRNA, and higher levels of Foxp3 mRNA in the splenic tissue of mice with enhanced HO-1 expression. Our results indicate that high expression of HO-1 may reduce the severity of aGVHD by regulation of the TH17/Treg balance.

Osteogenic differentiation and bone regeneration of iPSC-MSCs supported by a biomimetic nanofibrous scaffold

Induced pluripotent stem cell-derived mesenchymal stem cells (iPSC-MSCs) are a new type of MSCs that come with attractive merits over the iPSCs per se. Aimed for regenerating bone tissues, this study was designed to investigate osteogenic differentiation and bone regeneration capacities of iPSC-MSCs by using biomimetic nanofibers of hydroxyapatite/collagen/chitosan (HAp/Col/CTS). Murine iPSCs were firstly induced to differentiate into iPSC-MSCs and thoroughly characterized. Effects of HAp/Col/CTS nanofibers prepared from electrospinning of Col-doped HAp/CTS nanocomposite, on osteogenic differentiation of the generated iPSC-MSCs were then evaluated in detail, including cell morphology, proliferation, migration, quantified specific osteogenic gene and protein expressions. Compared with different controls (TCP, CTS, and HAp/CTS), the HAp/Col/CTS scaffold was found to have more favorable effects on attachment and proliferation of iPSC-MSCs than others (P<0.01). Expressions of osteogenic genes, Runx2, Ocn, Alp, and Col, were significantly upregulated in iPSC-MSCs cultured on HAp/Col/CTS than CTS (P<0.01). Similarly, there appeared considerably higher secreting activities of osteogenesis protein markers, ALP and Col. Furthermore, mouse cranial defects were created to investigate efficacy of using iPSC-MSCs in combination with HAp/Col/CTS scaffold for regenerative bone repair in vivo. Examinations by computed tomography (CT) imaging, bone mineral density and hematoxylin eosin (HE) staining corroborated that cell-scaffold construct of iPSC-MSCs+HAp/Col/CTS could effectively promote bone regeneration. After 6 weeks of implantation, bone mineral density of the iPSC-MSCs+HAp/Col/CTS group was found to be nearly 2-fold higher than others. Our results demonstrated that biomimetic nanofibers of HAp/Col/CTS promoted the osteogenic differentiation and bone regeneration of iPSC-MSCs. The iPSC-MSCs+HAp/Col/CTS complex could be used as a new 'stem cell-scaffold' system for realizing personalized and efficacious bone regeneration in future.

STATEMENT OF SIGNIFICANCE

In bone tissue engineering, stem cells have become the most important source of seed cells. iPSC-MSCs are a new type of MSCs that come with attractive merits over the iPSCs per se. However, how to obtain befitting iPSC-MSCs and regulate their osteogenic differentiation are the key issues to be addressed. Given the great biomimicking capacity to extracellular matrix, electrospun nanofibers may be explored to modulate osteogenic differentiation of the iPSC-MSCs. This study successfully demonstrated that biomimetic nanofibers of HAp/Col/CTS significantly promoted the osteogenic differentiation and bone regeneration of iPSC-MSCs, which thereby suggests that nanofibrous scaffold supported iPSC-MSCs complex may be a new 'stem cell-scaffold' system for regulating the fate of osteogenic differentiation of iPSC-MSCs towards patient-specific bone regeneration in future.

Foxp3-modified bone marrow mesenchymal stem cells promotes liver allograft tolerance through the generation of regulatory T cells in rats

Background

The transcription factor forkhead box P3 (Foxp3) is a master regulatory gene necessary for the development and function of CD4⁺CD25⁺ regulatory T cells (Tregs). Mesenchymal stem cells (MSC) have recently emerged as promising candidates for cell-based immunosuppression/tolerance induction protocols. Thus, we hypothesized that MSC-based Foxp3 gene therapy would improve immunosuppressive capacity of MSC and induce donor-specific allograft tolerance in rat’s liver allograft model.

Methods

The present study utilized a lentivirus vector to overexpress the therapeutic gene Foxp3 on MSC. In vivo, Injections of 2 × 10⁶ MSC, FUGW-MSC or Foxp3-MSC into the portal vein were carried out immediately after liver transplantation.

Results

Successful gene transfer of Foxp3 in MSC was achieved by lentivirus carrying Foxp3 and Foxp3-MSC engraftment in liver allograft was confirmed by fluorescence microscopy. Foxp3-MSC treatment significantly inhibited the proliferation of allogeneic ACI CD4⁺ T cells to splenocytes (SC) from the same donor strain or third-party BN rat compared with MSC. Foxp3-MSC suppressive effect on the proliferation of CD4⁺ T cells is contact dependent and associated with Programmed death ligand 1(PD-L1) upregulation in MSC. Co-culture of CD4⁺ T cells with Foxp3-MSC results in a shift towards a Tregs phenotype. More importantly, Foxp3-MSC monotherapy achieved donor-specific liver allograft tolerance and generated a state of CD4⁺CD25⁺Foxp3⁺ Tregs-dependent tolerance.

Conclusion

Foxp3-engineered MSC therapy seems to be a promising and attractive cell therapy approach for inducing immunosuppression or transplant tolerance.

Genetically modified human placenta‑derived mesenchymal stem cells with FGF‑2 and PDGF‑BB enhance neovascularization in a model of hindlimb ischemia

Ischemic diseases represent a challenging worldwide health burden. The current study investigated the therapeutic potential of genetically modified human placenta‑derived mesenchymal stem cells (hPDMSCs) with basic fibroblast growth factor (FGF2) and platelet‑derived growth factor‑BB (PDGF‑BB) genes in hindlimb ischemia. Mesenchymal stem cells obtained from human term placenta were transfected ex vivo with adenoviral bicistronic vectors carrying the FGF2 and PDGF‑BB genes (Ad‑F‑P). Unilateral hindlimb ischemia was surgically induced by excision of the right femoral artery in New Zealand White rabbits. Ad‑F‑P genetically modified hPDMSCs, Ad‑null (control vector)‑modified hPDMSCs, unmodified hPDMSCs or media were intramuscularly implanted into the ischemic limbs 7 days subsequent to the induction of ischemia. Four weeks after cell therapy, angiographic analysis revealed significantly increased collateral vessel formation in the Ad‑F‑P‑hPDMSC group compared with the control group. Histological examination revealed markedly increased capillary and arteriole density in the Ad‑F‑P‑hPDMSC group. The xenografted hPDMSCs survived in the ischemic tissue for at least 4 weeks subsequent to cell therapy. The current study demonstrated that the combination of hPDMSC therapy with FGF2 and PDGF‑BB gene therapy effectively induced collateral vessel formation and angiogenesis, suggesting a novel strategy for therapeutic angiogenesis.

Reconstruction and validation of a constraint-based metabolic network model for bone marrow-derived mesenchymal stem cells

OBJECTIVES

Over recent years, constraint-based modelling of metabolic networks has become increasingly popular; the models are suitable for system-level modelling of cell physiology. The goal of the present work was to reconstruct a constraint-based metabolic network model of bone marrow-derived mesenchymal stem cells (BMMSCs).

MATERIALS AND METHODS

To reconstruct a BMMSC-specific metabolic model, transcriptomic data of BMMSCs, and additionally, the human generic metabolic network model (Recon1) were used. Then, using the mCADRE algorithm, a draft metabolic network was reconstructed. Literature and proteomic data were subsequently used to refine and improve the draft. From this, iMSC1255 was derived to be the metabolic network model of BMMSCs.

RESULTS

iMSC1255 has 1255 genes, 1850 metabolites and 2288 reactions. After including additional constraints based on previously reported experimental results, our model successfully predicted BMMSC growth rate and metabolic phenotypes.

CONCLUSIONS

Here, iMSC1255 is introduced to be the metabolic network model of bone marrow-derived mesenchymal stem cells. Based on current knowledge, this is the first report on genome-scale reconstruction and validation of a stem cell metabolic network model.

Application of mesenchymal stem cells in digestive system diseases

Mesenchymal stem cells (MSCs) have the capacity of multipotent differentiation and the property of immunomodulation. MSCs have been widely used in digestive system disease research because of their advantageous characteristics such as homing to areas of inflammation or tumour tissue, anti-inflammation, high plasticity, absence of immunologic rejection, being easy to be isolated, and being convenient for the expression of exogenous genes. In this article, we will review the application of mesenchymal stem cells in digestive system diseases including caustic esophagus injury, reflux esophagitis, gastric ulcer, radioactive intestinal injury, severe acute pancreatitis, inflammatory bowel disease, nonalcoholic steatohepatitis, acute liver failure, hepatic fibrosis, autoimmune liver diseases, liver cirrhosis, esophageal cancer, gastric cancer, colon cancer, liver cancer, and pancreatic cancer.

Regenerative Therapy and Immune Modulation Using Umbilical Cord Blood-Derived Cells

Since the first cord blood transplantation in 1988, umbilical cord blood has become an important option as a source of cells for hematopoietic transplantation. Beyond its role in regenerating the blood and immune systems to treat blood diseases and inherited metabolic disorders, the role of nonhematopoietic progenitor cells in cord blood has led to new and emerging uses of umbilical cord blood in regenerative therapy and immune modulation. In this review, we provide an update on the clinical and preclinical studies using cord blood-derived cells such as mesenchymal stromal cells, endothelial-like progenitor cells, and others. We also provide insight on the use of cord blood cells as vehicles for the delivery of therapeutic agents through gene therapy and microvesicle-associated strategies. Moreover, cord blood can provide essential reagents for regenerative applications. Clinical activity using cord blood cells is increasing rapidly and this review aims to provide an important update on the tremendous potential within this fast-moving field.

Interleukin-17 and its implication in the regulation of differentiation and function of hematopoietic and mesenchymal stem cells

Adult stem cells have a great potential applicability in regenerative medicine and cell-based therapies. However, there are still many unresolved issues concerning their biology, and the influence of the local microenvironment on properties of stem cells has been increasingly recognized. Interleukin (IL-) 17, as a cytokine implicated in many physiological and pathological processes, should be taken into consideration as a part of a regulatory network governing tissue-associated stem cells' fate. This review is focusing on the published data on the effects of IL-17 on the properties and function of hematopoietic and mesenchymal stem cells and trying to discuss that IL-17 achieves many of its roles by acting on adult stem cells.

Mesenchymal stem cells as delivery vectors for anti-tumor therapy

Recent studies have demonstrated mesenchymal stem cells (MSCs) are able to migrate specifically to tumors and their metastatic sites when administered intravenously. This characteristic tumor tropism has opened up an emerging field to utilize MSCs as vectors to deliver anti-cancer agents for targeted therapies. Genetically engineered MSCs can specifically migrate to various tumors and locally secrete therapeutic proteins, such as interferon β (IFN-β) and IFN-γ, interleukin 12 and 24, tumor necrosis factor-related apoptosis inducing ligand (TRAIL) or suicide gene/enzyme prodrug. In addition, MSCs have also been engineered to deliver oncolytic viruses and drug-loaded nanoparticles. Here, we present the characteristics of MSCs, the current progress on MSC mediated anti-cancer agents delivery systems and the interaction between MSCs and tumors.

Tonsil-derived mesenchymal stromal cells produce CXCR2-binding chemokines and acquire follicular dendritic cell-like phenotypes under TLR3 stimulation

We previously isolated mesenchymal stromal cells from human tonsils (T-MSCs) and showed the potential of these cells to differentiate into the mesodermal lineage and acquire a follicular dendritic cell (FDC) phenotype under cytokine stimulation. Because these T-MSCs were originally isolated from inflamed tonsillar tissues, we were curious about their activation status in response to innate immune stimuli, such as Toll-like receptors (TLRs). Therefore, we analyzed the expression profile of TLRs in T-MSCs and stimulated the T-MSCs with TLR agonists. TLR3 stimuli induced C-C chemokine receptor type 6 expression in T-MSCs after 24h. Furthermore, results from cytokine arrays showed increases in epithelial neutrophil-activating peptide-78/C-X-C motif chemokine (CXCL) 5, granulocyte chemotactic protein-2/CXCL6, growth-related oncogene-α/CXCL1, interleukin-8/CXCL8, and interferon gamma-induced protein-10/CXCL10. CD54 expression was also increased after TLR3 stimulation. However, co-culturing T-MSCs with human B cells did not induce B-cell proliferation. This suggests that TLR3 stimulates the differentiation of T-MSCs into FDC-like cells and induces chemokine secretion, possibly by recruiting C-X-C chemokine receptor 2-expressing immune cells. In addition, T-MSCs also appeared to exert immunomodulatory effects by inhibiting B-cell proliferation, possibly by down-regulating CD18.

Application of stem cells in targeted therapy of breast cancer: a systematic review

BACKGROUND

The aim of this systematic review was to investigate whether stem cells could be effectively applied in targeted therapy of breast cancer.

MATERIAL AND METHOD

A systematic literature search was performed for original articles published from January 2007 until May 2012.

RESULTS

Nine studies met the inclusion criteria for phase I or II clinical trials, of which three used stem cells as vehicles, two trials used autologous hematopoetic stem cells and in four trials cancer stem cells were targeted. Mesenchymal stem cells (MSCs) were applied as cellular vehicles to transfer therapeutic agents. Cell therapy with MSC can successfully target resistant cancers. Cancer stem cells were selectively targeted via a proteasome-dependent suicide gene leading to tumor regression. Wnt/β-catenin signaling pathway has been also evidenced to be an attractive CSC-target.

CONCLUSIONS

This systematic review focused on two different concepts of stem cells and breast cancer marking a turning point in the trials that applied stem cells as cellular vehicles for targeted delivery therapy as well as CSC-targeted therapies. Applying stem cells as targeted therapy could be an effective therapeutic approach for treatment of breast cancer in the clinic and in therapeutic marketing; however this needs to be confirmed with further clinical investigations.

Stem cell therapy for neonatal hypoxic-ischemic encephalopathy

Treatments for neonatal hypoxic-ischemic encephalopathy (HIE) have been limited. The aim of this paper is to offer translational research guidance on stem cell therapy for neonatal HIE by examining clinically relevant animal models, practical stem cell sources, safety and efficacy of endpoint assays, as well as a general understanding of modes of action of this cellular therapy. In order to do so, we discuss the clinical manifestations of HIE, highlighting its overlapping pathologies with stroke and providing insights on the potential of cell therapy currently investigated in stroke, for HIE. To this end, we draw guidance from recommendations outlined in stem cell therapeutics as an emerging paradigm for stroke or STEPS, which have been recently modified to Baby STEPS to cater for the “neonatal” symptoms of HIE. These guidelines recognized that neonatal HIE exhibit distinct disease symptoms from adult stroke in need of an innovative translational approach that facilitates the entry of cell therapy in the clinic. Finally, new information about recent clinical trials and insights into combination therapy are provided with the vision that stem cell therapy may benefit from available treatments, such as hypothermia, already being tested in children diagnosed with HIE.

Mesenchymal stem cells for treatment of aortic aneurysms

An aortic aneurysm (AA) is a silent but life-threatening disease that involves rupture. It occurs mainly in aging and severe atherosclerotic damage of the aortic wall. Even though surgical intervention is effective to prevent rupture, surgery for the thoracic and thoraco-abdominal aorta is an invasive procedure with high mortality and morbidity. Therefore, an alternative strategy for treatment of AA is required. Recently, the molecular pathology of AA has been clarified. AA is caused by an imbalance between the synthesis and degradation of extracellular matrices in the aortic wall. Chronic inflammation enhances the degradation of matrices directly and indirectly, making control of the chronic inflammation crucial for aneurysmal development. Meanwhile, mesenchymal stem cells (MSCs) are known to be obtained from an adult population and to differentiate into various types of cells. In addition, MSCs have not only the potential anti-inflammatory and immunosuppressive properties but also can be recruited into damaged tissue. MSCs have been widely used as a source for cell therapy to treat various diseases involving graft-versus-host disease, stroke, myocardial infarction, and chronic inflammatory disease such as Crohn’s disease clinically. Therefore, administration of MSCs might be available to treat AA using anti-inflammatory and immnosuppressive properties. This review provides a summary of several studies on “Cell Therapy for Aortic Aneurysm” including our recent data, and we also discuss the possibility of this kind of treatment.

Mesenchymal stem cells infected with Mycoplasma arginini secrete complement C3 to regulate immunoglobulin production in B lymphocytes

Mesenchymal stem cells (MSCs) have immunomodulatory functions such as the suppression of T and B cells. MSCs suppress immunoglobulin (Ig) production by B cells via cell–cell contact as well as via secretion of soluble factors. Our study showed that the conditioned medium (CM) of MSCs infected with a mycoplasma strain, Mycoplasma arginini, has marked inhibitory effects on Ig production by lipopolysaccharide/interleukin-4-induced B cells compared with mycoplasma-free MSC-CM. We analyzed mycoplasma-infected MSC-CM by fast protein liquid chromatography and liquid chromatography to screen the molecules responsible for Ig inhibition. Complement C3 (C3) was the most critical molecule among the candidates identified. C3 was shown to be involved in the suppression of the Ig production of B cells. C3 was secreted by mycoplasma-infected MSCs, but not by mycoplasma-free MSCs or B cells. It was able to directly inhibit Ig production by B cells. In the presence of a C3 inhibitor, Ig inhibition by MSC-CM was abrogated. This inhibitory effect was concomitant with the downregulation of B-cell-induced maturation protein-1, which is a regulator of the differentiation of antibody-secreting plasma cells. These results suggest that C3 secreted from mycoplasma-infected MSCs has an important role in the immunomodulatory functions of MSCs. However, its role in vivo needs to be explored.

Therapeutic potential of bone marrow-derived mesenchymal stem cells in formed aortic aneurysms of a mouse model

OBJECTIVES

An aortic aneurysm (AA) is caused by atherosclerosis with chronic inflammation. Mesenchymal stem cells (MSCs) have potential anti-inflammatory properties. In this study, we examined whether an already-formed AA can be treated by intravenous injection of bone marrow-derived (BM)-MSCs in a mouse model.

METHODS

AA was induced in apolipoprotein E-deficient mice by angiotensin II-infusion for 28 days through sub-cutaneous osmotic mini-pumps. After that, 1 × 10(6) BM-MSCs (in 0.2 ml saline) or 0.2 ml saline as a control was injected via the tail vein. Mice were sacrificed at 2 (saline group n = 10, BM-MSC group n = 10), 4 (saline group n = 6, BM-MSC group n = 7) or 8 weeks (saline group n = 5, BM-MSC group n = 6) after injection. The aortic tissues of each group were dissected. Aortic diameter, elastin content, matrix metalloproteinase (MMP)-2 and -9 enzymatic activity and cytokine concentrations were measured, as was macrophage infiltration, which was also evaluated histologically.

RESULTS

The incidence of AA in the BM-MSC group was reduced at 2 weeks (BM-MSC 40% vs saline 100%, P < 0.05), and aortic diameter was reduced at 2 and 4 weeks (2 weeks: 1.40 vs 2.29 mm, P < 0.001; 4 weeks: 1.73 vs 2.32 mm, P < 0.05). The enzymatic activities of MMP-2 and -9 were reduced in the BM-MSC group at 2 weeks (active-MMP-2: 0.28 vs 0.45 unit/ml, P < 0.05; active-MMP-9: 0.16 vs 0.34 unit/ml, P < 0.05). Inflammatory cytokines were down-regulated in the BM-MSC group (interleukin-6: 2 weeks: 1475.6 vs 3399.5 pg/ml, P < 0.05; 4 weeks: 2184.7 vs 3712.8 pg/ml, P < 0.05 and monocyte chemotactic protein-1: 2 weeks: 208.0 vs 352.7 pg/ml, P < 0.05) and insulin-like growth factor (IGF)-1 and tissue inhibitor of metalloproteinase (TIMP)-2 were up-regulated in the BM-MSC group at 2 weeks (IGF-1: 4.7 vs 2.0 ng/ml, P < 0.05; TIMP-2: 9.5 vs 4.0 ng/ml, P < 0.001). BM-MSC injection inhibited infiltration of M1 macrophages and preserved the construction of elastin.

CONCLUSIONS

Our results suggest that BM-MSCs might be an effective treatment for AA. Further investigation is necessary to optimize the injected dosage and the frequency of BM-MSCs to prevent a transient effect.

Effectiveness of micron-sized superparamagnetic iron oxide particles as markers for detection of migration of bone marrow-derived mesenchymal stromal cells in a stroke model

PURPOSE

To evaluate the feasibility of using micron-sized superparamagnetic iron oxide particles (MPIOs) as an effective labeling agent for monitoring bone marrow-derived mesenchymal stromal cell (BMSC) migration in the brain using magnetic resonance imaging (MRI) in a rat model of stroke and whether the accumulation of MPIO-labeled BMSCs can be differentiated from the accumulation of free MPIO particles or hemoglobin breakdown at a site of neuronal damage.

MATERIALS AND METHODS

In this study BMSCs were labeled with iron oxide and their pattern of migration following intravenous injection in a rat stroke model was monitored using a clinical MRI system followed by standard histopathology. The migration pattern was compared between intravenous injection of BMSCs alone, BMSCs labeled with MPIOs, and MPIO particles alone.

RESULTS

The results demonstrated that while MRI was highly sensitive in the detection of iron oxide particle-containing cells in areas of neuronal ischemia, the true origin of cells containing iron oxide particles remains ambiguous. Therefore, detection of iron particles may not be a suitable strategy for the detection of BMSCs in the brain in a stroke model.

CONCLUSION

This study suggests that the use of MPIOs as labeling agents are insufficient to conclusively determine the localization of iron within cells in regions of neuronal ischemia and hemorrhage.

T cells from autoimmune patients display reduced sensitivity to immunoregulation by mesenchymal stem cells: role of IL-2

Mesenchymal stem cells (MSCs) are multipotent progenitor cells which have been shown to possess broad immunoregulatory and anti-inflammatory capabilities, making them a promising tool to treat autoimmune diseases (AIDs). Nevertheless, as in recent years T cells from AID patients have been found to resist suppression by regulatory T cells, the question of whether they could be regulated by MSCs arises. To use MSCs as a therapeutic tool in human autoimmune diseases, one prerequisite is that T cells from autoimmune patients will be sensitive to these stem cells. The aim of this work was to investigate the ability of healthy donor derived MSCs to inhibit the proliferation of T cells from two pathophysiologically different AIDs: Multiple Sclerosis (MS) and Myasthenia Gravis (MG). We show that MSC-induced inhibition of interferon-γ production and surface expression of the CD3, CD4 and CD28 receptors by activated lymphocytes was similar in the AID patients and healthy controls. Contrarily, the MSCs' ability to suppress the proliferation of T cells of both diseases was significantly weaker compared to their ability to affect T cells of healthy individuals. Although we found that the inhibitory mechanism is mediated through CD14+ monocytes, the faulty cellular component is the patients' T cells. MSC-treated MS and MG lymphocytes were shown to produce significantly more IL-2 than healthy subjects while coupling of the MSC treatment with neutralizing IL-2 antibodies resulted in inhibition levels similar to those of the healthy controls. MSCs were also found to down-regulate the lymphocyte surface expression of the IL-2 receptor (CD25) through both transcription inhibition and induction of receptor shedding. Addition of IL-2 to MSC-inhibited lymphocytes restored proliferation thus suggesting a key role played by this cytokine in the inhibitory mechanism. Taken together, these results demonstrate the potential of a MSC-based cellular therapy for MS, MG and possibly other autoimmune diseases but also highlight the need for a better understanding of the underlying mechanisms for development and optimization of clinical protocols.

Anti-tumor effect of adipose tissue derived-mesenchymal stem cells expressing interferon-β and treatment with cisplatin in a xenograft mouse model for canine melanoma

Adipose tissue-derived mesenchymal stem cells (AT-MSCs) are attractive cell-therapy vehicles for the delivery of anti-tumor molecules into the tumor microenvironment. The innate tropism of AT-MSCs for tumors has important implications for effective cellular delivery of anti-tumor molecules, including cytokines, interferon, and pro-drugs. The present study was designed to determine the possibility that the combination of stem cell-based gene therapy with low-dose cisplatin would improve therapeutic efficacy against canine melanoma. The IFN-β transduced canine AT-MSCs (cAT-MSC-IFN-β) inhibited the growth of LMeC canine melanoma cells in direct and indirect in vitro co-culture systems. In animal experiments using BALB/c nude mouse xenografts, which developed by injecting LMeC cells, the combination treatment of cAT-MSC-IFN-β and low-dose cisplatin significantly reduced tumor volume compared with the other treatment groups. Fluorescent microscopic analysis with a TUNEL (terminal deoxynucleotidyl transferase-mediated nick-end labeling) assay of tumor section provided evidence for homing of cAT-MSC-IFN-β to the tumor site and revealed that the combination treatment of cAT-MSC-IFN-β with low-dose cisplatin induced high levels of cell apoptosis. These findings may prove useful in further explorations of the application of these combined approaches to the treatment of malignant melanoma and other tumors.

Hepatocyte growth factor gene-modified bone marrow-derived mesenchymal stem cells transplantation promotes angiogenesis in a rat model of hindlimb ischemia

Angiogenic gene therapy and cell-based therapy for peripheral arterial disease(PAD) have been studied intensively currently. This study aimed to investigate whether combining mesenchymal stem cells(MSCs) transplantation with ex vivo human hepatocyte growth factor(HGF) gene transfer was more therapeutically efficient than the MSCs therapy alone in a rat model of hindlimb ischemia. One week after establishing hindlimb ischemia models, Sprague-Dawley(SD) rats were randomized to receive HGF gene-modified MSCs transplantation(HGF-MSC group), untreated MSCs transplantation (MSC group), or PBS injection(PBS group), respectively. Three weeks after injection, angiogenesis was significantly induced by both MSCs and HGF-MSCs transplantation, and capillary density was the highest in the HGF-MSC group. The number of transplanted cell-derived endothelial cells was greater in HGF-MSC group than in MSC group after one week treatment. The expression of angiogenic cytokines such as HGF and VEGF in local ischemic muscles was more abundant in HGF-MSC group than in the other two groups. In vitro, the conditioned media obtained from HGF-MSCs cultures exerted proproliferative and promigratory effects on endothelial cells. It is concluded that HGF gene-modified MSCs transplantation therapy may induce more potent angiogenesis than the MSCs therapy alone. Engraftment of MSCs combined with angiogenic gene delivery may be a promising therapeutic strategy for the treatment of severe PAD.

Aconiti Lateralis Preparata Radix Activates the Proliferation of Mouse Bone Marrow Mesenchymal Stem Cells and Induces Osteogenic Lineage Differentiation through the Bone Morphogenetic Protein-2/Smad-Dependent Runx2 Pathway

Mesenchymal stem cells have the capacity for self-renewal and under appropriate stimulation give rise to osteogenic, adipogenic, and chondrogenic lineages. To advance the clinical use of stem cell therapy, such as stem cell transplantation, it is important to find substances that promote endogenous stem cell proliferation and differentiation. We investigated whether medicinal herbs have the potential to promote stem cell proliferation and differentiation, using a cell cycle analysis and differentiation assay. We found that Aconiti Lateralis Preparata Radix (ALR) promoted the proliferation rate of mouse bone marrow mesenchymal stem cells (mBMMSCs) up to 122.24% compared to untreated cells. Fluorescence-activated cell sorter analysis showed that the percentage of cells in the G2/M phase increased to 17.33% in ALR-treated cells compared to 5.65% in normal cells. Signaling pathway analysis indicated that this was mediated through the extracellular signal-regulated kinase 1/2 pathway. A differentiation assay showed that ALR induced differentiation of mBMMSCs into an osteogenic lineage 2 weeks after treatment, whereas traditional osteogenic induction medium treatment did not promote differentiation for 3 weeks. This osteogenic differentiation was signaled by the bone morphogenetic protein-2/Smad-dependent Runx2 pathway. We found that ALR could promote mBMMSC proliferation and differentiation into the osteogenic lineage.