IFN-γ stimulation of dental follicle mesenchymal stem cells modulates immune response of CD4+ T lymphocytes in Der p1+ asthmatic patients in vitro

Mesenchymal Stromal Cells Derived from Dental Tissues: Immunomodulatory Properties and Clinical Potential

Mesenchymal stem/stromal cells (MSCs) are multipotent cells located in different areas of the human body. The oral cavity is considered a potential source of MSCs because they have been identified in several dental tissues (D-MSCs). Clinical trials in which cells from these sources were used have shown that they are effective and safe as treatments for tissue regeneration. Importantly, immunoregulatory capacity has been observed in all of these populations; however, this function may vary among the different types of MSCs. Since this property is of clinical interest for cell therapy protocols, it is relevant to analyze the differences in immunoregulatory capacity, as well as the mechanisms used by each type of MSC. Interestingly, D-MSCs are the most suitable source for regenerating mineralized tissues in the oral region. Furthermore, the clinical potential of D-MSCs is supported due to their adequate capacity for proliferation, migration, and differentiation. There is also evidence for their potential application in protocols against autoimmune diseases and other inflammatory conditions due to their immunosuppressive capacity. Therefore, in this review, the immunoregulatory mechanisms identified at the preclinical level in combination with the different types of MSCs found in dental tissues are described, in addition to a description of the clinical trials in which MSCs from these sources have been applied.

Intravenous transplantation of bone marrow-derived mesenchymal stromal cells in patients with multiple sclerosis, a phase I/IIa, double blind, randomized controlled study

Multiple sclerosis (MS) is a progressive, demyelinating neurodegenerative disease of the central nervous system. MS is immune-mediated and leads to disability especially in young adults. Even though 18 MS therapy drugs were approved, they slightly inhibit disease progression and do not induce regeneration and repair in the nervous system. Mesenchymal stromal cells (MSCs) have emerged as a new therapeutic modality in regenerative medicine and tissue engineering due to their immunomodulation and bio regenerative properties. We have designed a randomized, controlled clinical trial to assess safety and possible efficacy of MSC application in MS patients. Twenty-one MS patients were enrolled. Patients were allocated in two distinct groups: treatment group, which received systemic transplantation of autologous bone marrow-derived MSCs, and control group, which received placebo at the first injections. Patients in control group received MSCs at the second injection while the treatment group received placebo. All the patients were followed for 18 months. Follow-ups included regular visits, laboratory evaluation, and imaging analysis. Control patients received MSCs six month after treatment group. No severe immediate or late adverse events were observed in both groups after interventions. We did not find any significant differences in the rate of relapses, Expanded Disability Status Scale (EDSS) score, cognitive condition, Magnetic Resonance Imaging (MRI) findings, or any biomarkers of cerebrospinal fluid between the two groups and in each group before and after cell infusion. Transplantation of autologous bone marrow-derived mesenchymal stromal cells is safe and feasible. The efficacy of transplantation of these cells should be evaluated through designing randomized clinical trials with larger sample sizes, different administration routes, other cell types (allogeneic adipose derived MSCs, allogeneic Wharton's jelly derived MSCs …), repeated injections, and longer follow-up periods.

Mesenchymal Stem/Stromal Cells in Asthma Therapy: Mechanisms and Strategies for Enhancement

Asthma is a complex and heterogeneous disease characterized by chronic airway inflammation, airway hyperresponsiveness, and airway remodeling. Most asthmatic patients are well-established using standard treatment strategies and advanced biologicals. However, a small group of patients who do not respond to biological treatments or are not effectively controlled by available treatment strategies remain a clinical challenge. Therefore, new therapies are urgently needed for poorly controlled asthma. Mesenchymal stem/stromal cells (MSCs) have shown therapeutic potential in relieving airway inflammation and repairing impaired immune balance in preclinical trials owing to their immunomodulatory abilities. Noteworthy, MSCs exerted a therapeutic effect on steroid-resistant asthma with rare side effects in asthmatic models. Nevertheless, adverse factors such as limited obtained number, nutrient and oxygen deprivation in vitro, and cell senescence or apoptosis affected the survival rate and homing efficiency of MSCs, thus limiting the efficacy of MSCs in asthma. In this review, we elaborate on the roles and underlying mechanisms of MSCs in the treatment of asthma from the perspective of their source, immunogenicity, homing, differentiation, and immunomodulatory capacity and summarize strategies to improve their therapeutic effect.

Investigation of the effect of IFN-γ/TNF-α-treated mesenchymal stem cells on Th9- and Treg cell-related parameters in a mouse model of ovalbumin-induced allergic asthma

OBJECTIVE

Th9- and regulatory T (Treg) cells exert pro- and anti-allergic activity, respectively. Mesenchymal stem cell (MSC)-related immunomodulatory impacts can be enhanced by inflammatory cytokines. Here, the modulatory effects of IFN-γ/TNF-α-induced MSCs on Th9- and Treg cell-related parameters were investigated using an asthma model.

METHODS

Allergic asthma was induced in BALB/c mice using sensitized and challenging with ovalbumin (OVA). The asthmatic groups were treated intraperitoneally with PBS, MSCs, IFN-γ-induced MSCs, TNF-α-induced MSCs and "IFN-γ + TNF-α"-induced MSCs before the challenge phase. The mice were sacrificed 24 hours after challenge. The serum IL-9 and IL-35 levels, as well as gene expression of IL-9, PU.1, IL-35-EBI3 and FOXP3 in the lung tissues were assessed using ELISA and real time-PCR, respectively.

RESULTS

The differences of Th9 and Treg-related parameters were not significant between untreated asthmatic mice and those treated with non-induced MSCs. In comparison with untreated asthmatic group, treatment with IFN-γ-induced MSCs significantly reduced serum IL-9 levels, reduced lung expression of IL-9 and PU.1, while increasing serum IL-35 levels as well as lung expression of FOXP3; treatment with TNF-α-induced MSCs significantly reduced serum IL-9 levels as well as lung expression of IL-9, and treatment with "IFN-γ + TNF-α"-induced MSCs significantly modulated all investigated Th9 and Treg-related parameters. In comparison to mice treated with non-induced MSCs, serum IL-9 levels were remarkably decreased in mice treated with IFN-γ-induced and "IFN-γ + TNF-α"-induced MSCs.

CONCLUSIONS

IFN-γ-and "IFN-γ + TNF-α" treated MSCs exerted almost comparable impacts, but were more efficient than TNF-α-exposed MSCs. Thus, IFN-γ alone can be sufficient to promote immunomodulatory effects of MSCs.

Mechanisms during Osteogenic Differentiation in Human Dental Follicle Cells

Human dental follicle cells (DFCs) as periodontal progenitor cells are used for studies and research in regenerative medicine and not only in dentistry. Even if innovative regenerative therapies in medicine are often considered the main research area for dental stem cells, these cells are also very useful in basic research and here, for example, for the elucidation of molecular processes in the differentiation into mineralizing cells. This article summarizes the molecular mechanisms driving osteogenic differentiation of DFCs. The positive feedback loop of bone morphogenetic protein (BMP) 2 and homeobox protein DLX3 and a signaling pathway associated with protein kinase B (AKT) and protein kinase C (PKC) are presented and further insights related to other signaling pathways such as the WNT signaling pathway are explained. Subsequently, some works are presented that have investigated epigenetic modifications and non-coding ncRNAs and their connection with the osteogenic differentiation of DFCs. In addition, studies are presented that have shown the influence of extracellular matrix molecules or fundamental biological processes such as cellular senescence on osteogenic differentiation. The putative role of factors associated with inflammatory processes, such as interleukin 8, in osteogenic differentiation is also briefly discussed. This article summarizes the most important insights into the mechanisms of osteogenic differentiation in DFCs and is intended to be a small help in the direction of new research projects in this area.

Dental-derived cells for regenerative medicine: stem cells, cell reprogramming, and transdifferentiation

Embryonic stem cells have been a popular research topic in regenerative medicine owing to their pluripotency and applicability. However, due to the difficulty in harvesting them and their low yield efficiency, advanced cell reprogramming technology has been introduced as an alternative. Dental stem cells have entered the spotlight due to their regenerative potential and their ability to be obtained from biological waste generated after dental treatment. Cell reprogramming, a process of reverting mature somatic cells into stem cells, and transdifferentiation, a direct conversion between different cell types without induction of a pluripotent state, have helped overcome the shortcomings of stem cells and raised interest in their regenerative potential. Furthermore, the potential of these cells to return to their original cell types due to their epigenetic memory has reinforced the need to control the epigenetic background for successful management of cellular differentiation. Herein, we discuss all available sources of dental stem cells, the procedures used to obtain these cells, and their ability to differentiate into the desired cells. We also introduce the concepts of cell reprogramming and transdifferentiation in terms of genetics and epigenetics, including DNA methylation, histone modification, and non-coding RNA. Finally, we discuss a novel therapeutic avenue for using dental-derived cells as stem cells, and explain cell reprogramming and transdifferentiation, which are used in regenerative medicine and tissue engineering.

Function of Dental Follicle Progenitor/Stem Cells and Their Potential in Regenerative Medicine: From Mechanisms to Applications

Dental follicle progenitor/stem cells (DFPCs) are a group of dental mesenchyme stem cells that lie in the dental follicle and play a critical role in tooth development and maintaining function. Originating from neural crest, DFPCs harbor a multipotential differentiation capacity. More importantly, they have superiorities, including the easy accessibility and abundant sources, active self-renewal ability and noncontroversial sources compared with other stem cells, making them an attractive candidate in the field of tissue engineering. Recent advances highlight the excellent properties of DFPCs in regeneration of orofacial tissues, including alveolar bone repair, periodontium regeneration and bio-root complex formation. Furthermore, they play a unique role in maintaining a favorable microenvironment for stem cells, immunomodulation and nervous related tissue regeneration. This review is intended to summarize the current knowledge of DFPCs, including their stem cell properties, physiological functions and clinical application potential. A deep understanding of DFPCs can thus inspire novel perspectives in regenerative medicine in the future.

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.

House Dust Mite Allergy and the Der p1 Conundrum: A Literature Review and Case Series

The house dust mite (HDM) is globally ubiquitous in human habitats. Thirty-two allergens for Dermatophagoides farinae and 21 for Dermatophagoides pteronyssinus have been detected so far. The present minireview summarizes information about the role of Der p 1 as a key coordinator of the HDM-induced allergic response and reports on a series of Italian patients who are allergic to HDMs. We studied the specific IgE profiles in a population of patients with allergic asthma and rhinitis screened for specific immunotherapy (SIT) for HDM allergies, with the aim of obtaining insights into the pathogenic role of Der p1. Patients co-sensitized to other airborne allergens showed a higher prevalence of asthma (9/12 (75%) vs. 2/7 (29%); p < 0.05) than did HDM mono-sensitized patients. The latter group showed higher Der p1 concentrations than that of the co-sensitized group (p = 0.0360), and a direct correlation between Der p1 and Der p2 (r = 0.93; p = 0.0003) was observed. In conclusion, our study offers insights into the role of Der p1 in a population of patients with allergic rhinitis and asthma who were candidates for SIT. Interestingly, Der p1 positivity was associated with bronchial asthma and co-sensitization.

Mesenchymal Stem Cells in Asthma

Asthma is one of the worldwide respiratory health problem that affect children and adult. Current treatment strategies such as conventional and allergen immunotherapy still fall behind. Mesenchymal stem cells (MSCs) have wide regenerative capacity and immunoregulatory activity with their wide range of secretions and contact dependent manner. In this review, we focus on the current treatment strategies for asthma and MSCs as a new therapeutic tool.

Asthma immunotherapy and treatment approaches with mesenchymal stem cells

Asthma is a chronic inflammatory disease of the airways where exaggerated T helper 2 immune responses and inflammatory mediators play a role. Current asthma treatment options can effectively suppress symptoms and control the inflammatory process; however, cannot modulate the dysregulated immune response. Allergen-specific immunotherapy is one of the effective treatments capable of disease modification. Injecting allergens under the skin in allergen-specific immunotherapy can reduce asthma and improve the sensitivity of the lungs, however, has a risk of severe reactions. Mesenchymal stem cells have immunoregulatory activity with their soluble mediators and contact dependent manner. In this review, we focus on the current treatment strategies with mesenchymal stem cells in asthma as a new therapeutic tool and compare those with immunotherapy.

Immunomodulatory and Tissue-preserving Effects of Human Dental Follicle Stem Cells in a Rat Cecal Ligation and Perforation Sepsis Model

BACKGROUND

Mesenchymal stem cells may be used for the treatment of sepsis. Dental follicle stem cells (DFSCs) are easily accessible but have not been studied in vivo or in clinical trials in sepsis models.

AIM OF THE STUDY

We aim to elucidate DFSC effects on host immunological functions in a rat cecal ligation and perforation (CLP) sepsis model.

METHODS

Adult male rats were categorized into group 1 (sham procedure SP), group 2 (SP + 1 × 10⁶ DFSCs administered 0 h after SP), group 3 (CLP + saline), group 4 (CLP + 1 × 10⁶ DFSCs administered 0 h after CLP), and group 5 (CLP + 1 × 10⁶ DFSCs administered 4 h after CLP). Green fluorescent protein-labeled cells were used for imaging. Histopathological examination of ileal tissues was performed.

RESULTS

A significant increase in the percentage of CD4+/CD25+/Foxp3+ Treg cells in groups 4 and 5 occurred compared with that in group 3. No significant changes in CD3+/CD4+ helper T-cells and CD3+/CD8+ cytotoxic T-cells were observed. Treatment with DFSCs at 4 h significantly decreased the level of TNF-α compared with that in group 3. No significant changes in IL-10 levels and lymphocyte proliferation suppression were observed. During histopathological examination, no high scoring (Chiu scores: 3 or 4) rats were observed in the curative treatment group (group 5).

CONCLUSIONS

Treatment with DFSC after 4 h of sepsis induction downregulates tissue inflammatory responses by decreasing TNF-α levels and increasing Treg cell ratio. This also has a protective effect on intestinal tissues during sepsis.

Dental Follicle Cells: Roles in Development and Beyond

Dental follicle cells (DFCs) are a group of mesenchymal progenitor cells surrounding the tooth germ, responsible for cementum, periodontal ligament, and alveolar bone formation in tooth development. Cascades of signaling pathways and transcriptional factors in DFCs are involved in directing tooth eruption and tooth root morphogenesis. Substantial researches have been made to decipher multiple aspects of DFCs, including multilineage differentiation, senescence, and immunomodulatory ability. DFCs were proved to be multipotent progenitors with decent amplification, immunosuppressed and acquisition ability. They are able to differentiate into osteoblasts/cementoblasts, adipocytes, neuron-like cells, and so forth. The excellent properties of DFCs facilitated clinical application, as exemplified by bone tissue engineering, tooth root regeneration, and periodontium regeneration. Except for the oral and maxillofacial regeneration, DFCs were also expected to be applied in other tissues such as spinal cord defects (SCD), cardiomyocyte destruction. This article reviewed roles of DFCs in tooth development, their properties, and clinical application potentials, thus providing a novel guidance for tissue engineering.