Immune therapeutic potential of stem cells from human supernumerary teeth

Immunomodulatory Mechanism and Potential Application of Dental Pulp-Derived Stem Cells in Immune-Mediated Diseases

Dental pulp stem cells (DPSCs) are mesenchymal stem cells (MSCs) derived from dental pulp tissue, which have high self-renewal ability and multi-lineage differentiation potential. With the discovery of the immunoregulatory ability of stem cells, DPSCs have attracted much attention because they have similar or even better immunomodulatory effects than MSCs from other sources. DPSCs and their exosomes can exert an immunomodulatory ability by acting on target immune cells to regulate cytokines. DPSCs can also migrate to the lesion site to differentiate into target cells to repair the injured tissue, and play an important role in tissue regeneration. The aim of this review is to summarize the molecular mechanism and target cells of the immunomodulatory effects of DPSCs, and the latest advances in preclinical research in the treatment of various immune-mediated diseases, providing new reflections for their clinical application. DPSCs may be a promising source of stem cells for the treatment of immune-mediated diseases.

Tooth number abnormality: from bench to bedside

Tooth number abnormality is one of the most common dental developmental diseases, which includes both tooth agenesis and supernumerary teeth. Tooth development is regulated by numerous developmental signals, such as the well-known Wnt, BMP, FGF, Shh and Eda pathways, which mediate the ongoing complex interactions between epithelium and mesenchyme. Abnormal expression of these crutial signalling during this process may eventually lead to the development of anomalies in tooth number; however, the underlying mechanisms remain elusive. In this review, we summarized the major process of tooth development, the latest progress of mechanism studies and newly reported clinical investigations of tooth number abnormality. In addition, potential treatment approaches for tooth number abnormality based on developmental biology are also discussed. This review not only provides a reference for the diagnosis and treatment of tooth number abnormality in clinical practice but also facilitates the translation of basic research to the clinical application.

Mesenchymal stem cells and connective tissue diseases: From bench to bedside

The pathogenesis of connective tissue diseases (CTDs), represented by systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc), primary Sjögren’s syndrome (pSS), and idiopathic inflammatory myopathies (IIM), includes various immune cells involved in both innate and adaptive immunity. The mesenchymal stem cells (MSCs) are unique due to their regulatory effect on immunity. This makes them a promising therapeutic approach for patients with immune-mediated disorders such as CTD. The safety and clinical efficacy of MSC treatment in CTD have been tested in a growing number of preclinical and clinical studies. Administration of MSCs has consistently shown benefits with both symptomatic and histologic improvement in CTD animal models. MSC therapies in severe and drug-resistant CTD patients have shown promise in a number of the pilot studies, cohort studies, and randomized controlled trials in SLE, RA, and SSc, but some problems still need to be resolved in the transition from the bench to the bedside. The relevant studies in pSS and IIM are still in their infancy, but have displayed encouraging outcomes. Considerable efficacy variations have been observed in terms of the route of delivery, time of MSC injection, origin of the MSCs and dosage. Furthermore, the optimization of conventional drugs combined with MSC therapies and the applications of novel cell engineering approaches requires additional research. In this review, we summarize the current evidence about the immunoregulatory mechanism of MSCs, as well as the preclinical and clinical studies of MSC-based therapy for the treatment of CTDs.

Protocol to generate xenogeneic-free/serum-free human dental pulp stem cells

Human dental pulp stem cell (hDPSCs)-based therapy is a feasible option for regenerative medicine, such as dental pulp regeneration. Here, we show the steps needed to colony-forming unit-fibroblasts (CFU-F)-based isolation, expansion, and cryopreservation of hDPSCs for manufacturing clinical-grade products under a xenogeneic-free/serum-free condition. We also demonstrate the characterization of hDPSCs by CFU-F, flow cytometric, and in vitro multipotent assays. For complete details on the use and execution of this protocol, please refer to Iwanaka et al. (2020).

Immunomodulatory Activity of Mesenchymal Stem Cells in Lupus Nephritis: Advances and Applications

Lupus nephritis (LN) is a significant cause of various acute and chronic renal diseases, which can eventually lead to end-stage renal disease. The pathogenic mechanisms of LN are characterized by abnormal activation of the immune responses, increased cytokine production, and dysregulation of inflammatory signaling pathways. LN treatment is an important issue in the prevention and treatment of systemic lupus erythematosus. Mesenchymal stem cells (MSCs) have the advantages of immunomodulation, anti-inflammation, and anti-proliferation. These unique properties make MSCs a strong candidate for cell therapy of autoimmune diseases. MSCs can suppress the proliferation of innate and adaptive immune cells, such as natural killer cells (NKs), dendritic cells (DCs), T cells, and B cells. Furthermore, MSCs suppress the functions of various immune cells, such as the cytotoxicity of T cells and NKs, maturation and antibody secretion of B cells, maturation and antigen presentation of DCs, and inhibition of cytokine secretion, such as interleukins (ILs), tumor necrosis factor (TNF), and interferons (IFNs) by a variety of immune cells. MSCs can exert immunomodulatory effects in LN through these immune functions to suppress autoimmunity, improve renal pathology, and restore kidney function in lupus mice and LN patients. Herein, we review the role of immune cells and cytokines in the pathogenesis of LN and the mechanisms involved, as well as the progress of research on the immunomodulatory role of MSCs in LN.

A New Target of Dental Pulp-Derived Stem Cell-Based Therapy on Recipient Bone Marrow Niche in Systemic Lupus Erythematosus

Recent advances in mesenchymal stem/stromal cell (MSC) research have led us to consider the feasibility of MSC-based therapy for various diseases. Human dental pulp-derived MSCs (hDPSCs) have been identified in the dental pulp tissue of deciduous and permanent teeth, and they exhibit properties with self-renewal and in vitro multipotency. Interestingly, hDPSCs exhibit superior immunosuppressive functions toward immune cells, especially T lymphocytes, both in vitro and in vivo. Recently, hDPSCs have been shown to have potent immunomodulatory functions in treating systemic lupus erythematosus (SLE) in the SLE MRL/lpr mouse model. However, the mechanisms underlying the immunosuppressive efficacy of hDPSCs remain unknown. This review aims to introduce a new target of hDPSC-based therapy on the recipient niche function in SLE.

Application of dental pulp stem cells in oral maxillofacial tissue engineering

In the maxillofacial area, soft and hard tissue abnormalities are caused by trauma, tumors, infection, and other causes that expose the maxillofacial region to the surface of the human body. Patients' normal physiological function and appearance are interfered with, and their mental health is adversely impacted, reducing their overall life quality. The pursuit of appropriate medical treatments to correct these abnormalities is thus vital. Autologous stem cell regeneration technology mainly focused on tissues has lately emerged as a significant problem in the medical community. Because of the capacity of dental pulp stem cells (DPSCs) to self-renew, the use of DPSCs from the human pulp tissues of deciduous teeth or permanent teeth has gained popularity among scientists as a stem cell-based therapy option. Aside from that, they are simple to extract and have minimal immunogenicity. As a result, bone tissue engineering may be a critical component in treating maxillofacial and periodontal bone abnormalities. DPSCs activity in maxillofacial and periodontal tissue-engineered bone tissue was investigated in this research.

Overexpression of Hepatocyte Growth Factor in Dental Pulp Stem Cells Ameliorates the Severity of Psoriasis by Reducing Inflammatory Responses

Psoriasis is an autoimmune disease still lacking standard treatment, and it has been demonstrated that mesenchymal stem cells (MSCs) are capable of immunoregulation. The underlying mechanism might involve the secretion of soluble cytokines, such as hepatocyte growth factor (HGF). This study aims to investigate the therapeutic effect of HGF-overexpressed dental pulp stem cells (DPSCs) [DPSCs; HGF overexpressed DPSCs (HGF-DPSCs)] on imiquimod-induced psoriasis. DPSCs were isolated and transfected by adenovirus vector carrying HGF gene (Ad-HGF). The immunoregulatry abilities of DPSCs and HGF-DPSCs were investigated by coculture of the MSCs with peripheral blood mononuclear cells (PBMCs) under appropriated stimulation. The psoriatic mice were treated with saline control, DPSCs, or HGF-DPSCs. Then the mice spleens were collected and weighted. The psoriatic skin lesions were analyzed by Hematoxylin/Eosin and immunohistochemical staining for histopathological changes, and quantitative real-time polymerase chain reaction to detect the expression levels of CD4⁺ T cell-related transcription factors and cytokines. The mice blood serum was measured by MILLIPLEX analysis and enzyme-linked immunosorbent assay to evaluate the expression levels of inflammation cytokines. The coculture experiments showed HGF overexpression enhanced the immunoregulation abilities of DPSCs not by suppressing PBMCs' proliferation, but by downregulating T helper 1 (Th1), Th17 cells, and upregulating regulatory T (Treg) cells. In psoriatic skin lesions, the psoriasis-like erythema, scaling, and thickening were ameliorated; and the expression of cytokeratin 6 (CK6), and cytokeratin 17 (CK17) were downregulated by DPSCs and HGF-DPSCs treatment. HGF overexpression enhanced the decrease of spleen masses; enhanced the downregulation of the expression levels of interferon-gamma (IFN-γ), tumor necrosis factor-α, and interleukin (IL)-17A in the blood serums; enhanced the downregulation of T-box transcription factor 21 (T-bet), IFN-γ, retinoic acid-related orphan receptor-γt (RORγt), IL-17A, IL-17F, IL-23, and upregulation of Foxp3 and IL-10 in the psoriatic skin lesions. Therefore, HGF overexpression enhanced DPSCs' treatment effect on psoriasis mainly by reducing inflammatory responses. These findings might provide new immunoregulation strategies for psoriasis treatment.

Immunomodulatory functions of oral mesenchymal stem cells: Novel force for tissue regeneration and disease therapy

Mesenchymal stem cells (MSCs)-based therapeutic strategies have achieved remarkable efficacies. Oral tissue-derived MSCs, with powerful self-renewal and multilineage differentiation abilities, possess the features of abundant sources and easy accessibility and hold great potential in tissue regeneration and disease therapies. Oral MSCs mainly consist of periodontal ligament stem cells, gingival mesenchymal stem cells, dental pulp stem cells, stem cells from human exfoliated deciduous teeth, stem cells from the apical papilla, dental follicle stem cells, and alveolar bone-derived mesenchymal stem. Early immunoinflammatory response stage is the prerequisite phase of healing process. Besides the potent capacities of differentiation and regeneration, oral MSCs are capable of interacting with various immune cells and function as immunomodulatory regulators. Consequently, the immunomodulatory effects of oral MSCs during damage repair seem to be crucial for exploring novel immunomodulatory strategies to achieve disease recovery and tissue regeneration. Herein, we reviewed various oral MSCs with their immunomodulatory properties and the potential mechanism, as well as their effects on immunomodulation-mediated disease therapies and tissue regeneration.

The immunomodulatory effects of mesenchymal stromal cell-based therapy in human and animal models of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune inflammatory disease with no absolute cure. Although the exact etiopathogenesis of SLE is still enigmatic, it has been well demonstrated that a combination of genetic predisposition and environmental factors trigger a disturbance in immune responses and thereby participate in the development of this condition. Almost all available therapeutic strategies in SLE are primarily based on the administration of immunosuppressive drugs and are not curative. Mesenchymal stromal cells (MSCs) are a subset of non-hematopoietic adult stem cells that can be isolated from many adult tissues and are increasingly recognized as immune response modulating agents. MSC-mediated inhibition of immune responses is a complex mechanism that involves almost every aspect of the immune response. MSCs suppress the maturation of antigen-presenting cells (DC and MQ), proliferation of T cells (Th1, T17, and Th2), proliferation and immunoglobulin production of B cells, the cytotoxic activity of CTL and NK cells in addition to increasing regulatory cytokines (TGF-β and IL10), and decreasing inflammatory cytokines (IL17, INF-ϒ, TNF-α, and IL12) levels. MSCs have shown encouraging results in the treatment of several autoimmune diseases, in particular SLE. This report aims to review the beneficial and therapeutic properties of MSCs; it also focuses on the results of animal model studies, preclinical studies, and clinical trials of MSC therapy in SLE from the immunoregulatory aspect.

The Potential of Different Origin Stem Cells in Modulating Oral Bone Regeneration Processes

Tissue engineering has gained much momentum since the implementation of stem cell isolation and manipulation for regenerative purposes. Despite significant technical improvements, researchers still have to decide which strategy (which type of stem cell) is the most suitable for their specific purpose. Therefore, this short review discusses the advantages and disadvantages of the three main categories of stem cells: embryonic stem cells, mesenchymal stem cells and induced pluripotent stem cells in the context of bone regeneration for dentistry-associated conditions. Importantly, when deciding upon the right strategy, the selection needs to be made in concordance with the morbidity and the life-threatening level of the condition in discussion. Therefore, even when a specific type of stem cell holds several advantages over others, their availability, invasiveness of the collection method and ethical standards become deciding parameters.

The Use of Human Mesenchymal Stem Cells as Therapeutic Agents for the in vivo Treatment of Immune-Related Diseases: A Systematic Review

Background: One of the greatest challenges for medicine is to find a safe and effective treatment for immune-related diseases. However, due to the low efficacy of the treatment available and the occurrence of serious adverse effects, many groups are currently searching for alternatives to the traditional therapy. In this regard, the use of human mesenchymal stem cells (hMSCs) represents a great promise for the treatment of a variety of immune-related diseases due to their potent immunomodulatory properties. The main objective of this study is, therefore, to present and summarize, through a systematic review of the literature, in vivo studies in which the efficacy of the administration of hMSCs for the treatment of immune-related diseases was evaluated. Methods: The article search was conducted in PubMed/MEDLINE, Scopus and Web of Science databases. Original research articles assessing the therapeutic potential of hMSCs administration for the in vivo treatment immune-related diseases, published from 1984 to December 2017, were selected and evaluated. Results: A total of 132 manuscripts formed the basis of this systematic review. Most of the studies analyzed reported positive results after hMSCs administration. Clinical effects commonly observed include an increase in the survival rates and a reduction in the severity and incidence of the immune-related diseases studied. In addition, hMSCs administration resulted in an inhibition in the proliferation and activation of CD19⁺ B cells, CD4⁺ Th1 and Th17 cells, CD8⁺ T cells, NK cells, macrophages, monocytes, and neutrophils. The clonal expansion of both Bregs and Tregs cells, however, was stimulated. Administration of hMSCs also resulted in a reduction in the levels of pro-inflammatory cytokines such as IFN-γ, TNF-α, IL-1, IL-2, IL-12, and IL-17 and in an increase in the levels of immunoregulatory cytokines such as IL-4, IL-10, and IL-13. Conclusions: The results obtained in this study open new avenues for the treatment of immune-related diseases through the administration of hMSCs and emphasize the importance of the conduction of further studies in this area.

Local myogenic pulp-derived cell injection enhances craniofacial muscle regeneration in vivo

OBJECTIVES

To enhance myogenic differentiation in pulp cells isolated from extracted premolars by epigenetic modification using a DNA demethylation agent, 5-aza-2'-deoxycytidine (5-Aza), and to evaluate the potent stimulatory effect of 5-Aza-treated pulp cell injection for craniofacial muscle regeneration in vivo.

SETTING AND SAMPLE POPULATION

Pulp cells were isolated from premolars extracted for orthodontic purposes from four adults (age range, 18-22.1 years).

MATERIAL AND METHODS

Levels of myogenic differentiation and functional contraction response in vitro were compared between pulp cells with or without pre-treatment of 5-Aza. Changes in muscle regeneration in response to green fluorescent protein (GFP)-labelled myogenic pulp cell injection in vivo were evaluated using a cardiotoxin (CTX)-induced muscle injury model of the gastrocnemius as well as the masseter muscle in mice.

RESULTS

Pre-treatment of 5-Aza in pulp cells stimulated myotube formation, myogenic differentiation in terms of desmin and myogenin expression, and the level of collagen gel contraction. The local injection of 5-Aza pre-treated myogenic pulp cells was engrafted into the host tissue and indicated signs of enhanced muscle regeneration in both the gastrocnemius and the masseter muscles.

CONCLUSION

The epigenetic modification of pulp cells from extracted premolars and the local injection of myogenic pulp cells may stimulate craniofacial muscles regeneration in vivo.

Progress in the use of dental pulp stem cells in regenerative medicine

The field of tissue engineering is emerging as a multidisciplinary area with promising potential for regenerating new tissues and organs. This approach requires the involvement of three essential components: stem cells, scaffolds and growth factors. To date, dental pulp stem cells have received special attention because they represent a readily accessible source of stem cells. Their high plasticity and multipotential capacity to differentiate into a large array of tissues can be explained by its neural crest origin, which supports applications beyond the scope of oral tissues. Many isolation, culture and cryopreservation protocols have been proposed that are known to affect cell phenotype, proliferation rate and differentiation capacity. The clinical applications of therapies based on dental pulp stem cells demand the development of new biomaterials suitable for regenerative purposes that can act as scaffolds to handle, carry and implant stem cells into patients. Currently, the development of xeno-free culture media is emerging as a means of standardization to improve safe and reproducibility. The present review aims to describe the current knowledge of dental pulp stem cells, considering in depth the key aspects related to the characterization, establishment, maintenance and cryopreservation of primary cultures and their involvement in the multilineage differentiation potential. The main clinical applications for these stem cells and their combination with several biomaterials is also covered.

A novel mutation of adenomatous polyposis coli (APC) gene results in the formation of supernumerary teeth

Supernumerary teeth are teeth that are present in addition to normal teeth. Although several hypotheses and some molecular signalling pathways explain the formation of supernumerary teeth, but their exact disease pathogenesis is unknown. To study the molecular mechanisms of supernumerary tooth‐related syndrome (Gardner syndrome), a deeper understanding of the aetiology of supernumerary teeth and the associated syndrome is needed, with the goal of inhibiting disease inheritance via prenatal diagnosis. We recruited a Chinese family with Gardner syndrome. Haematoxylin and eosin staining of supernumerary teeth and colonic polyp lesion biopsies revealed that these patients exhibited significant pathological characteristics. APC gene mutations were detected by PCR and direct sequencing. We revealed the pathological pathway involved in human supernumerary tooth development and the mouse tooth germ development expression profile by RNA sequencing (RNA‐seq). Sequencing analysis revealed that an APC gene mutation in exon 15, namely 4292‐4293‐Del GA, caused Gardner syndrome in this family. This mutation not only initiated the various manifestations typical of Gardner syndrome but also resulted in odontoma and supernumerary teeth in this case. Furthermore, RNA‐seq analysis of human supernumerary teeth suggests that the APC gene is the key gene involved in the development of supernumerary teeth in humans. The mouse tooth germ development expression profile shows that the APC gene plays an important role in tooth germ development. We identified a new mutation in the APC gene that results in supernumerary teeth in association with Gardner syndrome. This information may shed light on the molecular pathogenesis of supernumerary teeth. Gene‐based diagnosis and gene therapy for supernumerary teeth may become available in the future, and our study provides a high‐resolution reference for treating other syndromes associated with supernumerary teeth.

Comparative Analyses of Immunosuppressive Characteristics of Bone-Marrow, Wharton's Jelly, and Adipose Tissue-Derived Human Mesenchymal Stem Cells

Objective:

Mesenchymal stem cells (MSCs), which possess immunosuppressive characteristics on induced T-cells, were shown to be applicable in prevention and treatment of graft-versus-host disease. However, knowledge of effective cell sources is still limited. In this study, MSCs from different human tissues, i.e. bone marrow (BM), Wharton’s jelly (WJ), and adipose tissue, were isolated, and the immune suppression of stimulated T cells was analyzed comparatively.

Materials and Methods:

MSCs were co-cultured with phytohemagglutinin-induced T-cells with co-culture techniques with and without cell-to-cell contact. After co-culture for 24 and 96 h, the proliferation rate of T cells was estimated by carboxyfluorescein succinimidyl ester and apoptosis by annexin V/PI methods. Both T cells and MSCs were analyzed with respect to gene expressions by real-time polymerase chain reaction and their specific protein levels by ELISA.

Results:

The results showed that all three MSC lines significantly suppressed T-cell proliferation; BM-MSCs were most effective. Similarly, T-cell apoptosis was induced most strongly by BM-MSCs in indirect culture. In T cells, the genes in NFkB and tumor necrosis factor pathways were silenced and the caspase pathway was induced after co-culture. These results were confirmed with the measurement of protein levels, like transforming growth factor β1, IL-6, interferon-γ, interleukin (IL)-2, and tumor necrosis factor-α. Additionally, IL-17A was detected in high levels in WJ-MSC co-cultures. We showed that IL-17A-producing Tregs are the key mediators in the treatment of graft-versus-host disease.

Conclusion:

BM-MSCs, which have been used in clinical applications for a while, showed the greatest immunosuppressive effect compared to other MSCs. However, a promising cell source could also be WJ, which is also effective in suppression with fewer ethical concerns. We described the molecular mechanism of WJ-MSCs in allogenic transplants for the first time.

The Promising Applications of Stem Cells in the Oral Region: Literature Review

INTRODUCTION

For a long time researchers have tried to find out a way to grow tissues back to the human body in order to solve transplantation problems by offering the unique opportunity to have their organs back, working properly, in search of life dignity.

LITERATURE REVIEW

Stem cells seem to be present in many other tissues than researchers had once thought; and in some specific sites they can be easily collected, without the need of expensive interventions. The oral cavity is one of these regions where their collection can be accomplished, with plenty of accessible sites enriched with these precious cells.

AIM

The aim of this literature review is to research where in the mouth can scientists find stem cells to be used in the near future.

KEY-MESSAGE

The aim of this literature review is to research where stem cells can be found and collected in the oral cavity.

Interferon-gamma improves impaired dentinogenic and immunosuppressive functions of irreversible pulpitis-derived human dental pulp stem cells

Clinically, irreversible pulpitis is treated by the complete removal of pulp tissue followed by replacement with artificial materials. There is considered to be a high potential for autologous transplantation of human dental pulp stem cells (DPSCs) in endodontic treatment. The usefulness of DPSCs isolated from healthy teeth is limited. However, DPSCs isolated from diseased teeth with irreversible pulpitis (IP-DPSCs) are considered to be suitable for dentin/pulp regeneration. In this study, we examined the stem cell potency of IP-DPSCs. In comparison with healthy DPSCs, IP-DPSCs expressed lower colony-forming capacity, population-doubling rate, cell proliferation, multipotency, in vivo dentin regeneration, and immunosuppressive activity, suggesting that intact IP-DPSCs may be inadequate for dentin/pulp regeneration. Therefore, we attempted to improve the impaired in vivo dentin regeneration and in vitro immunosuppressive functions of IP-DPSCs to enable dentin/pulp regeneration. Interferon gamma (IFN-γ) treatment enhanced in vivo dentin regeneration and in vitro T cell suppression of IP-DPSCs, whereas treatment with tumor necrosis factor alpha did not. Therefore, these findings suggest that IFN-γ may be a feasible modulator to improve the functions of impaired IP-DPSCs, suggesting that autologous transplantation of IFN-γ-accelerated IP-DPSCs might be a promising new therapeutic strategy for dentin/pulp tissue engineering in future endodontic treatment.

Transplantation of mesenchymal stem cells ameliorates secondary osteoporosis through interleukin-17-impaired functions of recipient bone marrow mesenchymal stem cells in MRL/lpr mice

Introduction

Secondary osteoporosis is common in systemic lupus erythematosus and leads to a reduction in quality of life due to fragility fractures, even in patients with improvement of the primary disorder. Systemic transplantation of mesenchymal stem cells could ameliorate bone loss and autoimmune disorders in a MRL/lpr mouse systemic lupus erythematosus model, but the detailed therapeutic mechanism of bone regeneration is not fully understood. In this study, we transplanted human bone marrow mesenchymal stem cells (BMMSCs) and stem cells from exfoliated deciduous teeth (SHED) into MRL/lpr mice and explored their therapeutic mechanisms in secondary osteoporotic disorders of the systemic lupus erythematosus model mice.

Methods

The effects of systemic human mesenchymal stem cell transplantation on bone loss of MRL/lpr mice were analyzed in vivo and ex vivo. After systemic human mesenchymal stem cell transplantation, recipient BMMSC functions of MRL/lpr mice were assessed for aspects of stemness, osteogenesis and osteoclastogenesis, and a series of co-culture experiments under osteogenic or osteoclastogenic inductions were performed to examine the efficacy of interleukin (IL)-17-impaired recipient BMMSCs in the bone marrow of MRL/lpr mice.

Results

Systemic transplantation of human BMMSCs and SHED recovered the reduction in bone density and structure in MRL/lpr mice. To explore the mechanism, we found that impaired recipient BMMSCs mediated the negative bone metabolic turnover by enhanced osteoclastogenesis and suppressed osteoblastogenesis in secondary osteoporosis of MRL/lpr mice. Moreover, IL-17-dependent hyperimmune conditions in the recipient bone marrow of MRL/lpr mice damaged recipient BMMSCs to suppress osteoblast capacity and accelerate osteoclast induction. To overcome the abnormal bone metabolism, systemic transplantation of human BMMSCs and SHED into MRL/lpr mice improved the functionally impaired recipient BMMSCs through IL-17 suppression in the recipient bone marrow and then maintained a regular positive bone metabolism via the balance of osteoblasts and osteoclasts.

Conclusions

These findings indicate that IL-17 and recipient BMMSCs might be a therapeutic target for secondary osteoporosis in systemic lupus erythematosus.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0091-4) contains supplementary material, which is available to authorized users.

Infusion of Human Bone Marrow-Derived Mesenchymal Stem Cells Alleviates Autoimmune Nephritis in a Lupus Model by Suppressing Follicular Helper T-Cell Development

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the production of autoantibodies to components of the cell nucleus. These autoantibodies are predominantly produced with the help of follicular helper T (Tfh) cells and form immune complexes that trigger widespread inflammatory damage, including nephritis. In recent studies, mesenchymal stem cells (MSCs) elicited diverse, even opposing, effects in experimental and clinical SLE. Here we investigated the effect of human bone marrow-derived MSCs (hBM-MSCs) in a murine model of SLE, the F1 hybrid between New Zealand Black and New Zealand White strains (NZB/W). We found that infusion of female NZB/W mice with hBM-MSCs attenuated glomerulonephritis; it also decreased levels of autoantibodies and the incidence of proteinuria and improved survival. These effects coincided with a decrease in Tfh cells and downstream components. Infiltration of long-lived plasma cells into the inflamed kidney was also reduced in the hBM-MSC-treated mice. Importantly, hBM-MSCs directly suppressed the in vitro differentiation of naive CD4(+) T cells toward Tfh cells in a contact-dependent manner. These results suggest that MSCs attenuate lupus nephritis by suppressing the development of Tfh cells and the subsequent activation of humoral immune components. They thus reveal a novel mechanism by which MSCs regulate humoral autoimmune diseases such as SLE.

Endoplasmic reticulum stress participates in the progress of senescence of bone marrow-derived mesenchymal stem cells in patients with systemic lupus erythematosus

Previous studies suggested that the senescence of bone marrow mesenchymal stem cells (BM-MSCs) played an important role in the pathological process of systemic lupus erythematosus (SLE). However, the molecular mechanisms that govern this phenomenon have not been fully elucidated. Recent studies reported the activation of endoplasmic reticulum stress (ERS) participated in the growth arrest in G1 phase of cell cycle. In this study, we aimed to investigate whether ERS would induce the senescence of BM-MSCs from SLE patients. We found that there was increased expression of Glucose Regulated Protein 78 (GRP 78) in BM-MSCs from SLE patients, which indicated the activation of ERS in BM-MSCs from SLE patients. Accumulation of p27 was also found in BM-MSCs from SLE patients. Interestingly, as a chemical chaperone helping the correct folding of proteins, 4-phenylbutyric acid (4-PBA) partly rescued the senescence of BM-MSCs from SLE patients and alleviated the level of p27. These results implicated ERS-mediated senescence as a critical determinant of BM-MSCs from SLE patients.

Immunological basis of stem cell therapy in liver diseases

Unbalanced immune cell populations or immune cell infiltration of the liver can disrupt the immune-privileged state of the liver, resulting in liver injury or fibrosis. Therefore, the treatment for liver diseases involves not only hepatic regeneration but also immunological regulation. Recent studies demonstrated that stem cells, especially mesenchymal stem cells, have the capacity for not only hepatic differentiation but also immunomodulation. In this respect, stem cell therapy could be a realistic aim for liver diseases by modulating the liver regenerative processes and down-regulating immune-mediated liver damage. In this review, we discuss in detail the importance of immune cells in liver injury and repair; the mechanism by which stem cells demonstrate an immune-tolerant phenotype that can be used for allogeneic transplantation; the effect of stem cell transplantation on immune-mediated diseases, especially liver diseases; and the mechanism by which stem cells improve the hepatic microenvironment.

Umbilical cord mesenchymal stem cells: the new gold standard for mesenchymal stem cell-based therapies?

Due to their self-renewal capacity, multilineage differentiation potential, paracrine effects, and immunosuppressive properties, mesenchymal stromal cells (MSCs) are an attractive and promising tool for regenerative medicine. MSCs can be isolated from various tissues but despite their common immunophenotypic characteristics and functional properties, source-dependent differences in MSCs properties have recently emerged and lead to different clinical applications. Considered for a long time as a medical waste, umbilical cord appears these days as a promising source of MSCs. Several reports have shown that umbilical cord-derived MSCs are more primitive, proliferative, and immunosuppressive than their adult counterparts. In this review, we aim at synthesizing the differences between umbilical cord MSCs and MSCs from other sources (bone marrow, adipose tissue, periodontal ligament, dental pulp,…) with regard to their proliferation capacity, proteic and transcriptomic profiles, and their secretome involved in their regenerative, homing, and immunomodulatory capacities. Although umbilical cord MSCs are until now not particularly used as an MSC source in clinical practice, accumulating evidence shows that they may have a therapeutic advantage to treat several diseases, especially autoimmune and neurodegenerative diseases.

Novel approaches to lupus drug discovery using stem cell therapy. Role of mesenchymal-stem-cell-secreted factors

INTRODUCTION

Patients with systemic lupus erythematosus (SLE) are at increased risk for premature death, particularly among young adults, and present dilemmas regarding drug efficacy versus toxicity. Novel therapeutic strategies have included the use of mesenchymal stem cell (MSC) therapies that are promising but still have limitations. In several disease models, it has become apparent that MSCs do not necessarily replace diseased tissues but rather exert complex paracrine effects that are mediated by their extracellular-secreted products.

AREAS COVERED

In this review, the authors highlight the data on MSC treatment of SLE and related mechanisms of actions. This data includes the recent evidence that MSC-secreted factors such as extracellular microvesicles (MVs) are important mediators of MSC therapy. Among MVs, the authors delineate the role of exosomes as triggers of regenerative effects in target cells, mediated by transfer of proteins, mRNAs or microRNAs. The authors also outline some of the biological and regulatory restraints encountered by MSC therapy, in contrast to the potential advantages of MSC-derived exosomes as new therapeutic tools in SLE.

EXPERT OPINION

There is concern about reproducible data on the use of MSC therapy in rheumatic diseases and specifically SLE. Although most experts consider MSCs to be safe, there are still worries over donor variability, immune-mediated rejection, culture-induced senescence, loss of functional properties and genetic instability or eventual malignant transformation. MSC-released factors could avoid most limiting factors associated with cell therapy and are therefore expected to provide a new and safe therapeutic option at an affordable cost.

Sjögren's syndrome: where do we stand, and where shall we go?

Primary Sjögren's syndrome (pSS) is one of the most frequent autoimmune systemic diseases, mainly characterized by ocular and oral dryness due to the progressive destruction of lachrymal and salivary glands by an inflammatory process. A noteworthy proportion of patients also features extraglandular manifestations, sometimes severe and life-threatening. Until now, its management relies mostly on symptomatic interventions, long-term monitoring, and, in patients with severe systemic complications, immunosuppressive drugs can be provided. However, recent years have seen great progresses in the understanding of the pathological processes of the disease. The central role of regulatory lymphocytes, the implication of the type 1 interferon pathway in some patients or the importance of epigenetics have been highlighted. New classification criteria have been recently published and have shed in light an international attempt for a better recognition of the patients, probably thanks to the development of new diagnostic procedures such as salivary gland ultrasonography. To facilitate the detection of treatment efficacy in clinical trials and to help in determining which subgroups of patients would have benefits from intensive therapies, a better definition of activity scores and the availability of new prognostic markers are urgent. Thereby, the development of future therapies should be based on specific molecular signatures that will enable a personalized management of each patient. This review focuses on the most striking advances in the fields of pathophysiology, diagnosis and treatment of pSS, which generate a great hope for pSS patients.

Therapeutic potential of interleukin-17 in inflammation and autoimmune diseases

INTRODUCTION

Interleukin-17 (IL-17) is a proinflammatory cytokine that mainly produced by T helper 17 (Th17) cells. In this article, we discussed the role of IL-17 in inflammation and autoimmune diseases, and the therapeutic strategies targeting IL-17.

AREAS COVERED

In this article, we discussed the proinflammatory cytokine IL-17 and IL-17 receptors signals, and their regulation. IL-17 expression was abnormal in the bacterium, virus and fungus infection, and its higher level caused the tissue inflammation. IL-17 was involved in the pathological process of autoimmune diseases, such as systemic sclerosis, rheumatoid arthritis, ankylosing spondylitis and systemic lupus erythematosus, and IL-17 has been put as a therapeutic target in the clinic.

EXPERT OPINION

IL-17/IL-17R signals and their application in inflammation process still need to be explored. Therapeutic strategies targeting IL-17 in autoimmune diseases ameliorated the inadequate response to anti-TNF-α therapy.

Comparison of human mesenchymal stem cells derived from dental pulp, bone marrow, adipose tissue, and umbilical cord tissue by gene expression

AIMS

Our aims were to characterize human mesenchymal stem cells isolated from various tissues by pluripotent stem cells gene expression profile.

METHODS

Four strains of dental pulp stem cells (DP-MSCs) were isolated from dental pulp tissue fragments adhered to plastic tissue culture dishes. Mesenchymal stem cells derived from umbilical cord tissue (UBC-MSCs) were isolated with the same technique. Bone marrow derived mesenchymal stem cells (BM-MSCs) were isolated from nucleated cells of bone marrow obtained by density gradient centrifugation. Human mesenchymal stem cells from adipose tissue (AT-MSCs) were isolated by collagenase digestion. All kinds of MSCs used in this study were cultivated in low glucose DMEM containing 5% or human platelet extract. All stem cell manipulation was performed in GMP conditions. Expression of 15 pluripotent stem cells genes on the level of proteins was measured by Proteome Profiler Human Pluripotent Stem Cell Array. Induction of MSCs to in vitro differentiation to adipocytes, osteoblasts, chondroblasts was achieved by cultivation of cells in appropriate differentiation medium.

RESULTS

All MSCs tested were phenotypically similar and of fibroblastoid morphology. DP-MSCs and UBC-MSCs were more proliferative than bone marrow BM-MSCs and AT-MSCs. Protein expression of 15 genes typical for pluripotent stem cells distinguished them into two groups. While the gene expression profiles of BM-MSC, AT-MSCs and UBC-MSCs were similar, DP-MSCS differed in relative gene expression on the level of their products in several genes.

CONCLUSIONS

Dental pulp mesenchymal stem cells cultivated in vitro under the same conditions as MSCs from bone marrow, adipose tissue and umbilical cord tissue can be distinguished by pluripotent stem cell gene expression profile.