The Fas/Fap-1/Cav-1 Complex Regulates IL-1RA Secretion in Mesenchymal Stem Cells to Accelerate Wound Healing

Mesenchymal stem cells (MSCs) are capable of secreting exosomes, extracellular vesicles, and cytokines to regulate cell and tissue homeostasis. However, it is unknown whether MSCs use a specific exocytotic fusion mechanism to secrete exosomes and cytokines. We show that Fas binds with Fas-associated phosphatase–1 (Fap-1) and caveolin-1 (Cav-1) to activate a common soluble N-ethylmaleimide–sensitive factor (NSF) attachment protein receptor (SNARE)–mediated membrane fusion mechanism to release small extracellular vesicles (sEVs) in MSCs. Moreover, we reveal that MSCs produce and secrete interleukin-1 receptor antagonist (IL-1RA) associated with sEVs to maintain rapid wound healing in the gingiva via the Fas/Fap-1/Cav-1 cascade. Tumor necrosis factor–α (TNF-α) serves as an activator to up-regulate Fas and Fap-1 expression via the nuclear factor κB pathway to promote IL-1RA release. This study identifies a previously unknown Fas/Fap-1/Cav-1 axis that regulates SNARE-mediated sEV and IL-1RA secretion in stem cells, which contributes to accelerated wound healing

Pluronic F-127 hydrogel as a promising scaffold for encapsulation of dental-derived mesenchymal stem cells.

Dental-derived mesenchymal stem cells (MSCs) provide an advantageous therapeutic option for tissue engineering due to their high accessibility and bioavailability. However, delivering MSCs to defect sites while maintaining a high MSC survival rate is still a critical challenge in MSC-mediated tissue regeneration. Here, we tested the osteogenic and adipogenic differentiation capacity of dental pulp stem cells (DPSCs) in a thermoreversible Pluronic F127 hydrogel scaffold encapsulation system in vitro. DPSCs were encapsulated in Pluronic (®) F-127 hydrogel and stem cell viability, proliferation and differentiation into adipogenic and osteogenic tissues were evaluated. The degradation profile and swelling kinetics of the hydrogel were also analyzed. Our results confirmed that Pluronic F-127 is a promising and non-toxic scaffold for encapsulation of DPSCs as well as control human bone marrow MSCs (hBMMSCs), yielding high stem cell viability and proliferation. Moreover, after 2 weeks of differentiation in vitro, DPSCs as well as hBMMSCs exhibited high levels of mRNA expression for osteogenic and adipogenic gene markers via PCR analysis. Our histochemical staining further confirmed the ability of Pluronic F-127 to direct the differentiation of these stem cells into osteogenic and adipogenic tissues. Furthermore, our results revealed that Pluronic F-127 has a dense tubular and reticular network morphology, which contributes to its high permeability and solubility, consistent with its high degradability in the tested conditions. Altogether, our findings demonstrate that Pluronic F-127 is a promising scaffold for encapsulation of DPSCs and can be considered for cell delivery purposes in tissue engineering

Ecological Balance of Oral Microbiota is Required to Maintain Oral Mesenchymal Stem Cell Homeostasis

Oral microbiome is essential for maintenance of oral cavity health. Imbalanced oral microbiome causes periodontal and other diseases. It is unknown whether oral microbiome affect oral stem cells function. In this study, we used a common clinical anti-biotic treatment approach to alter oral microbiome ecology and examine whether oral mesenchymal stem cells (MSCs) are affected. We found that altered oral microbiome resulted gingival MSCs deficiency, leading to a delayed wound healing in male mice. Mechanistically, oral microbiome release LPS that stimulates the expression of microRNA-21 (miR-21) and then impair the normal function of gingival MSCs and wound healing process through miR-21/Sp1/TERT pathway. This is the first study indicate that interplay between oral microbiome and MSCs homeostasis in male mice

Dental Mesenchymal Stem Cells Encapsulated in Alginate Hydrogel Co-Delivery Microencapsulation System for Cartilage Regeneration

Dental-derived MSCs are promising candidates for cartilage regeneration, with high chondrogenic differentiation capacity. This property contributes to making dental MSCs an advantageous therapeutic option compared to current treatment modalities. The MSC delivery vehicle is the principal determinant for the success of MSC-mediated cartilage regeneration therapies. The objectives of this study were to: (1) develop a novel co-delivery system based on TGF-β1 loaded RGD-coupled alginate microspheres encapsulating Periodontal Ligament Stem Cells (PDLSCs) or Gingival Mesenchymal Stem Cells (GMSCs); and (2) investigate dental MSC viability and chondrogenic differentiation in alginate microspheres. The results revealed the sustained release of TGF-β1 from the alginate microspheres. After 4 weeks of chondrogenic differentiation in vitro, PDLSCs, GMSCs as well as human bone marrow mesenchymal stem cells (hBMMSC) (as positive control) revealed chondrogenic gene expression markers (Col II and Sox-9) via qPCR, as well as matrix positively stained by toluidine blue and safranin-O. In animal studies, ectopic cartilage tissue regeneration was observed inside and around the transplanted microspheres, confirmed by histochemical and immunofluorescent staining. Interestingly, PDLSCs showed more chondrogenesis than GMSCs and hBMMSCs (P\u3c0.05). Taken together, these results suggest that RGD-modified alginate microencapsulating dental MSCs make a promising candidate for cartilage regeneration. Our results highlight the vital role played by the microenvironment, as well as value of presenting inductive signals for viability and differentiation of MSCs

Dental Mesenchymal Stem Cells Encapsulated in Alginate Hydrogel Co-Delivery Microencapsulation System for Cartilage Regeneration

Dental-derived MSCs are promising candidates for cartilage regeneration, with high chondrogenic differentiation capacity. This property contributes to making dental MSCs an advantageous therapeutic option compared to current treatment modalities. The MSC delivery vehicle is the principal determinant for the success of MSC-mediated cartilage regeneration therapies. The objectives of this study were to: (1) develop a novel co-delivery system based on TGF-β1 loaded RGD-coupled alginate microspheres encapsulating Periodontal Ligament Stem Cells (PDLSCs) or Gingival Mesenchymal Stem Cells (GMSCs); and (2) investigate dental MSC viability and chondrogenic differentiation in alginate microspheres. The results revealed the sustained release of TGF-β1 from the alginate microspheres. After 4 weeks of chondrogenic differentiation in vitro, PDLSCs, GMSCs as well as human bone marrow mesenchymal stem cells (hBMMSC) (as positive control) revealed chondrogenic gene expression markers (Col II and Sox-9) via qPCR, as well as matrix positively stained by toluidine blue and safranin-O. In animal studies, ectopic cartilage tissue regeneration was observed inside and around the transplanted microspheres, confirmed by histochemical and immunofluorescent staining. Interestingly, PDLSCs showed more chondrogenesis than GMSCs and hBMMSCs (

Basic Fibroblast Growth Factor Inhibits Osteogenic Differentiation of SHED through ERK Signaling

Objective Stem cells from human exfoliated deciduous teeth (SHED) are a unique postnatal stem cell population capable of regenerating mineralized tissue and treating immune disorders. However, the mechanism that controls SHED differentiation is not fully understood. Here, we showed that basic fibroblast growth factor (bFGF) treatment attenuated SHED-mediated mineralized tissue regeneration through activation of the extracellular signal-regulated kinase (ERK) 1/2 pathway. Material and Method The level of mineralized nodule formation was assessed by alizarin red staining. Expression levels of osteogenic genes, OCN and Runx2, were examined by RT-PCR. Subcutaneous implantation approach was used to assess in vivo bone formation. Downstream signaling pathways of bFGF were examined by Western blotting. Result Activation of ERK1/2 signaling by bFGF treatment inhibited WNT/β-catenin pathway, leading to osteogenic deficiency of SHED. ERK1/2 inhibitor treatment rescued bFGF-induced osteogenic differentiation deficiency. Conclusion These data suggest that bFGF inhibits osteogenic differentiation of SHED via ERK1/2 pathway. Blockade ERK1/2 signaling by small molecular inhibitor-treatment improves bone formation of SHED after bFGF treatment

Human Periodontal Ligament- and Gingiva-derived Mesenchymal Stem Cells Promote Nerve Regeneration When Encapsulated in Alginate/hyaluronic Acid 3D Scaffold

Repair or regeneration of damaged nerves is still a challenging clinical task in reconstructive surgeries and regenerative medicine. Here, we demonstrate that periodontal ligament stem cells (PDLSCs) and gingival mesenchymal stem cells (GMSCs) isolated from adult human periodontal and gingival tissues assume neuronal phenotype in vitro and in vivo via a subcutaneous transplantation model in nude mice. PDLSCs and GMSCs were encapsulated in a three-dimensional scaffold based on alginate and hyaluronic acid hydrogels capable of sustained release of human nerve growth factor (NGF). We demonstrate that, the elasticity of the hydrogels affected the proliferation and differentiation of encapsulated MSCs within scaffolds. Moreover, we observed that PDLSCs and GMSCs were stained positive for βIII-tubulin, while exhibiting high levels of gene expression related to neurogenic differentiation (βIII-tubulin and GFAP) via qPCR. Western blot analysis showed the importance of the elasticity of the matrix and the presence of NGF in the neurogenic differentiation of encapsulated MSCs. In vivo, immunofluorescence staining for neurogenic specific protein markers confirmed islands of dense positively stained structures inside transplanted hydrogels. To our knowledge, this study is the first demonstration of the application of PDLSCs and GMSCs as promising cell therapy candidates for nerve regeneration

Mesenchymal Stem Cell-Induced Immunoregulation Involves Fas Ligand/Fas-Mediated T Cell Apoptosis

Systemic infusion of bone marrow mesenchymal stem cells (BMMSCs) shows therapeutic benefit for a variety of autoimmune diseases, but the underlying mechanisms are poorly understood. Here we show that in mice systemic infusion of BMMSCs induced transient T-cell apoptosis via the Fas ligand (FasL)-dependent Fas pathway and could ameliorate disease phenotypes in fibrillin-1 mutated systemic sclerosis (SS) and dextran sulfate sodium-induced experimental colitis. FasL−/− BMMSCs did not induce T-cell apoptosis in recipients, and could not ameliorate SS and colitis. Mechanistic analysis revealed that Fas-regulated monocyte chemotactic protein 1 (MCP-1) secretion by BMMSCs recruited T-cells for FasL-mediated apoptosis. The apoptotic T-cells subsequently triggered macrophages to produce high levels of TGFβ which in turn led to the upregulation of Tregs and, ultimately, to immune tolerance. These data therefore demonstrate a previously unrecognized mechanism underlying BMMSC-based immunotherapy involving coupling via Fas/FasL to induce T-cell apoptosis

IFN-γ and TNF-α Synergistically Induce Mesenchymal Stem Cell Impairment and Tumorigenesis via NFκB Signaling

An inflammatory microenvironment may cause organ degenerative diseases and malignant tumors. However, the precise mechanisms of inflammation-induced diseases are not fully understood. Here we show that the proinflammatory cytokines interferon γ (IFN-γ) and tumor necrosis factor α (TNF-α) synergistically impair self-renewal and differentiation of mesenchymal stem cells (MSCs) via nuclear factor κB (NFκB)–mediated activation of Mothers against decapentaplegic homolog 7 (SMAD7) in ovariectomized (OVX) mice. More interestingly, a long-term elevated levels of IFN-γ and TNF-α result in significantly increased susceptibility to malignant transformation in MSCs through NFκB–mediated upregulation of the oncogenes c-Fos and c-Myc. Depletion of either IFN-γ or TNF-α in OVX mice abolishes MSC impairment and the tendency toward malignant transformation with no NFκB–mediated oncogene activation. Systemic administration of aspirin, which significantly reduces the levels of IFN-γ and TNF-α, results in blockage of MSC deficiency and tumorigenesis by inhibition of NF-κB/SMAD7 and NFκB/c-FOS and c-MYC pathways in OVX mice. In summary, this study reveals that inflammation factors, such as IFN-γ and TNF-α, synergistically induce MSC deficiency via NFκB/SMAD7 signaling and tumorigenesis via NFκB–mediated oncogene activation