Tonsil-derived mesenchymal stromal cells: evaluation of biologic, immunologic and genetic factors for successful banking

Therapeutic Effect of Schwann Cell-Like Cells Differentiated from Human Tonsil-Derived Mesenchymal Stem Cells on Diabetic Neuropathy in db/db Mice

BACKGROUND

Diabetic neuropathy (DN) is the most common complication of diabetes, and approximately 50% of patients with this disease suffer from peripheral neuropathy. Nerve fiber loss in DN occurs due to myelin defects and is characterized by symptoms of impaired nerve function. Schwann cells (SCs) are the main support cells of the peripheral nervous system and play important roles in several pathways contributing to the pathogenesis and development of DN. We previously reported that human tonsil-derived mesenchymal stem cells differentiated into SCs (TMSC-SCs), named neuronal regeneration-promoting cells (NRPCs), which cells promoted nerve regeneration in animal models with peripheral nerve injury or hereditary peripheral neuropathy.

METHODS

In this study, NRPCs were injected into the thigh muscles of BKS-db/db mice, a commonly used type 2 diabetes model, and monitored for 26 weeks. Von Frey test, sensory nerve conduction study, and staining of sural nerve, hind foot pad, dorsal root ganglia (DRG) were performed after NRPCs treatment.

RESULTS

Von Frey test results showed that the NRPC treatment group (NRPC group) showed faster responses to less force than the vehicle group. Additionally, remyelination of sural nerve fibers also increased in the NRPC group. After NRPCs treatment, an improvement in response to external stimuli and pain sensation was expected through increased expression of PGP9.5 in the sole and TRPV1 in the DRG.

CONCLUSION

The NRPCs treatment may alleviate DN through the remyelination and the recovery of sensory neurons, could provide a better life for patients suffering from complications of this disease.

Podoplanin depletion in tonsil-derived mesenchymal stem cells induces cellular senescence via regulation of the p16Ink4a/Rb pathway

BACKGROUND

Mesenchymal stem cells (MSCs) are widely used in the development of therapeutic tools in regenerative medicine. However, their quality decreases during in vitro expansion because of heterogeneity and acquired cellular senescence. We investigated the potential role of podoplanin (PDPN) in minimizing cellular senescence and maintaining the stemness of tonsil-derived MSCs (TMSCs).

METHODS

TMSCs were isolated from human tonsil tissues using an enzymatic method, expanded, and divided into two groups: early-passaged TMSCs, which were cultured for 3-7 passages, and late-passaged TMSCs, which were passaged more than 15 times. The TMSCs were evaluated for cellular senescence and MSC characteristics, and PDPN-positive and -negative cells were identified by fluorescence-activated cell sorting. In addition, MSC features were assessed in siRNA-mediated PDPN-depleted TMSCs.

RESULTS

TMSCs, when passaged more than 15 times and becoming senescent, exhibited reduced proliferative rates, telomere length, pluripotency marker (NANOG, OCT4, and SOX2) expression, and tri-lineage differentiation potential (adipogenesis, chondrogenesis, or osteogenesis) compared to cells passaged less than five times. Furthermore, PDPN protein levels significantly decreased in a passage-dependent manner. PDPN-positive cells maintained their stemness characteristics, such as MSC-specific surface antigen (CD14, CD34, CD45, CD73, CD90, and CD105) and pluripotency marker expression, and exhibited higher tri-lineage differentiation potential than PDPN-negative cells. SiRNA-mediated silencing of PDPN led to decreased cell-cycle progression, proliferation, and migration, indicating the significance of PDPN as a preliminary senescence-related factor. These reductions directly contributed to the induction of cellular senescence via p16Ink4a/Rb pathway activation.

CONCLUSION

PDPN may serve as a novel biomarker to mitigate cellular senescence in the clinical application of MSCs.

Parathyroid-on-a-chip simulating parathyroid hormone secretion in response to calcium concentration

The parathyroid gland is an endocrine organ that plays a crucial role in regulating calcium levels in blood serum through the secretion of parathyroid hormone (PTH). Hypoparathyroidism is a chronic disease that can occur due to parathyroid defects, but due to the difficulty of creating animal models of this disease or obtaining human normal parathyroid cells, the evaluation of parathyroid functionality for drug development is limited. Although parathyroid-like cells that secrete PTH have recently been reported, their functionality may be overestimated using traditional culture methods that lack in vivo similarities, particularly vascularization. To overcome these limitations, we obtained parathyroid organoids from tonsil-derived mesenchymal stem cells (TMSCs) and fabricated a parathyroid-on-a-chip, capable of simulating PTH secretion based on calcium concentration. This chip exhibited differences in PTH secretion according to calcium concentration and secreted PTH within the range of normal serum levels. In addition, branches of organoids, which are difficult to observe in animal models, were observed in this chip. This could serve as a guideline for successful engraftment in implantation therapies in the future.

Oral ulcer treatment using human tonsil-derived mesenchymal stem cells encapsulated in trimethyl chitosan hydrogel: an animal model study

BACKGROUND

Oral ulcers are a common side effect of chemotherapy and affect patients' quality of life. While stem cell transplantation is a potential treatment for oral ulcers, its efficacy is limited as the stem cells tend to remain in the affected area for a short time. This study aims to develop a treatment for oral ulcers by using trimethyl chitosan (TMC) hydrogel with human tonsil-derived stem cells (hTMSCs) to increase the therapeutic effect of stem cells and investigate their effectiveness.

METHODS

Animals were divided into four experimental groups: Control, TMC hydrogel, hTMSCs, and hTMSCs loaded in TMC hydrogel (Hydrogel + hTMSCs) (each n = 8). Oral ulcers were chemically induced by anesthetizing the rats followed by injection of dilute acetic acid in the right buccal mucosa. After confirming the presence of oral ulcers in the animals, a single subcutaneous injection of 100 µL of each treatment was applied to the ulcer area. Histological analyses were performed to measure inflammatory cells, oral mucosal thickness, and fibrosis levels. The expression level of inflammatory cytokines was also measured using RT-PCR to gauge therapeutic the effect.

RESULTS

The ulcer size was significantly reduced in the TMC hydrogel + hTMSCs group compared to the control group. The stem cells in the tissue were only observed until Day 3 in the hTMSCs treated group, while the injected stem cells in the TMC Hydrogel + hTMSCs group were still present until day 7. Cytokine analysis related to the inflammatory response in the tissue confirmed that the TMC Hydrogel + hTMSCs treated group demonstrated superior wound healing compared to other experimental groups.

CONCLUSION

This study has shown that the adhesion and viability of current stem cell therapies can be resolved by utilizing a hydrogel prepared with TMC and combining it with hTMSCs. The combined treatment can promote rapid healing of oral cavity wounds by enhancing anti-inflammatory effects and expediting wound healing. Therefore, hTMSC loaded in TMC hydrogel was the most effective wound-healing approach among all four treatment groups prolonging stem cell survival. However, further research is necessary to minimize the initial inflammatory response of biomaterials and assess the safety and long-term effects for potential clinical applications.

Immunomodulatory Effects of Primed Tonsil-Derived Mesenchymal Stem Cells on Atopic Dermatitis via B Cell Regulation

Mesenchymal stem cells (MSCs) ameliorate T-and B cell-mediated immune responses. In particular, tonsil-MSCs (T-MSCs) are attractive candidates for practical and clinical applications because of their ease of acquisition and relatively low immunogenicity compared with other MSC sources. The use of MSCs as a therapeutic tool in atopic dermatitis (AD) has been investigated, but that of T-MSCs remains to be explored. Therefore, we investigated the immunomodulatory effects of primed T-MSCs in AD pathogenesis. In our animal study, primed T-MSCs showed greater immunological suppressive effects than naïve T-MSCs. Additionally, in vitro, the proliferation of B cells was downregulated by the addition of primed T-MSCs compared with naïve T-MSCs. The activation of B cells to differentiate into antibody-secreting cells and produce IgE was also reduced when primed T-MSCs were added. Moreover, under CD40-knockdown conditions, we found that CD40 in primed T-MSCs played a critical role as a regulator of B cell activation and was mediated by the non-canonical NF-κB pathway. Therefore, our findings suggest a promising role for primed T-MSCs in the treatment of AD by regulating B cell-mediated inflammatory responses, which are dependent on CD40 expression on primed T-MSCs mediated through the non-canonical NF-κB pathway.

CD49f and CD146: A Possible Crosstalk Modulates Adipogenic Differentiation Potential of Mesenchymal Stem Cells

BACKGROUND

The lack of appropriate mesenchymal stem cells (MSCs) selection methods has given the challenges for standardized harvesting, processing, and phenotyping procedures of MSCs. Genetic engineering coupled with high-throughput proteomic studies of MSC surface markers arises as a promising strategy to identify stem cell-specific markers. However, the technical limitations are the key factors making it less suitable to provide an appropriate starting material for the screening platform. A more accurate, easily accessible approach is required to solve the issues.

METHODS

This study established a high-throughput screening strategy with forward versus side scatter gating to identify the adipogenesis-associated markers of bone marrow-derived MSCs (BMSCs) and tonsil-derived MSCs (TMSCs). We classified the MSC-derived adipogenic differentiated cells into two clusters: lipid-rich cells as side scatter (SSC)-high population and lipid-poor cells as SSC-low population. By screening the expression of 242 cell surface proteins, we identified the surface markers which exclusively found in lipid-rich subpopulation as the specific markers for BMSCs and TMSCs.

RESULTS

High-throughput screening of the expression of 242 cell surface proteins indicated that CD49f and CD146 were specific for BMSCs and TMSCs. Subsequent immunostaining confirmed the consistent specific expression of CD49f and CD146 and in BMSCs and TMSCs. Enrichment of MSCs by CD49f and CD146 surface markers demonstrated that the simultaneous expression of CD49f and CD146 is required for adipogenesis and osteogenesis of mesenchymal stem cells. Furthermore, the fate decision of MSCs from different sources is regulated by distinct responses of cells to differentiation stimulations despite sharing a common CD49f+CD146+ immunophenotype.

CONCLUSIONS

We established an accurate, robust, transgene-free method for screening adipogenesis associated cell surface proteins. This provided a valuable tool to investigate MSC-specific markers. Additionally, we showed a possible crosstalk between CD49f and CD146 modulates the adipogenesis of MSCs.

Preclinical Efficacy of Peripheral Nerve Regeneration by Schwann Cell-like Cells Differentiated from Human Tonsil-Derived Mesenchymal Stem Cells in C22 Mice

Charcot-Marie-Tooth disease (CMT) is a hereditary disease with heterogeneous phenotypes and genetic causes. CMT type 1A (CMT1A) is a type of disease affecting the peripheral nerves and is caused by the duplication of the peripheral myelin protein 22 (PMP22) gene. Human tonsil-derived mesenchymal stem cells (TMSCs) are useful for stem cell therapy in various diseases and can be differentiated into Schwann cell-like cells (TMSC-SCs). We investigated the potential of TMSC-SCs called neuronal regeneration-promoting cells (NRPCs) for peripheral nerve and muscle regeneration in C22 mice, a model for CMT1A. We transplanted NRPCs manufactured in a good manufacturing practice facility into the bilateral thigh muscles of C22 mice and performed behavior and nerve conduction tests and histological and ultrastructural analyses. Significantly, the motor function was much improved, the ratio of myelinated axons was increased, and the G-ratio was reduced by the transplantation of NRPCs. The sciatic nerve and gastrocnemius muscle regeneration of C22 mice following the transplantation of NRPCs downregulated PMP22 overexpression, which was observed in a dose-dependent manner. These results suggest that NRPCs are feasible for clinical research for the treatment of CMT1A patients. Research applying NRPCs to other peripheral nerve diseases is also needed.

Enhanced Intervertebral Disc Repair via Genetically Engineered Mesenchymal Stem Cells with Tetracycline Regulatory System

The therapeutic potential of Mesenchymal stem cells (MSCs) for the treatment of Intervertebral disc (IVD) degeneration can be enhanced by amplifying specific cytokines and proteins. This study aimed to investigate the therapeutic potential of tetracycline-off system-engineered tonsil-derived mesenchymal stem cells (ToMSC-Tetoff-TGFβ1-IGF1-BMP7) for treating intervertebral disc (IVD) degeneration. ToMSCs were isolated from a tonsillectomy patient and genetically modified with four distinct plasmids via CRISPR/Cas9-mediated knock-in gene editing. Transgene expression was confirmed through immunofluorescence, western blots, and an enzyme-linked immunosorbent assay for transforming growth factor beta 1 (TGFβ1) protein secretion, and the effect of MSC-TetOff-TGFβ1-IGF1-BMP7 on disc injury was assessed in a rat model. The ToMSC-Tetoff-TGFβ1-IGF1-BMP7 treatment exhibited superior therapeutic effects compared to ToMSC-TGFβ1, and ToMSC-SDF1α implantation groups, stimulating the regeneration of nucleus pulposus (NP) cells crucial for IVD. The treatment showed potential to restore the structural integrity of the extracellular matrix (ECM) by upregulating key molecules such as aggrecan and type II collagen. It also exhibited anti-inflammatory properties and reduced pain-inducing neuropeptides. ToMSC-Tetoff-TGFβ1-IGF1-BMP7 holds promise as a novel treatment for IVD degeneration. It appears to promote NP cell regeneration, restore ECM structure, suppress inflammation, and reduce pain. However, more research and clinical trials are required to confirm its therapeutic potential.

Photobiomodulation enhances M2 macrophage polarization properties of tonsil-derived mesenchymal stem cells

In this study, the effect of photobiomodulation (PBM) treatment using 630 nm light emitting diode (LED) array (continuous wave type, 10 mW power) on tonsil-derived mesenchymal stem cells (TMSCs) and its interaction with RAW 264.7 macrophage cells via co-culture in vitro were investigated. PBM treatment was used as a priming method for TMSCs to improve therapeutic efficacy. TMSCs were subjected to multi-dose PBM treatments before co-culture with M1 activated (1 μg/mL lipopolysaccharide, LPS) macrophage cells with total energy doses of 0, 15, 30, and 60 J. Irradiation set at 15 J (1500 s treatment time) was performed once, twice for 30 J, and four times for 60 J in an incubator kept at 37 °C and 5% CO2. No significant anti-inflammatory response was observed for TMSCs co-cultured with macrophage cells without PBM. But PBM treatment of TMSCs with 630 nm LED array at 30 J reduced expression of inducible nitric oxide synthase, iNOS (M1) and increased expression of Arginase-1, Arg-1 (M2) phenotype macrophage markers. Anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA) gene expression also increased significantly. Based on the results, PBM priming of TMSCs supports M2 macrophage polarization. PBM can be used to improve the therapeutic efficacy of TMSCs for potential applications in oral mucositis and wound healing.

Adult Mesenchymal Stem Cells from Oral Cavity and Surrounding Areas: Types and Biomedical Applications

Adult mesenchymal stem cells are those obtained from the conformation of dental structures (DMSC), such as deciduous and permanent teeth and other surrounding tissues. Background: The self-renewal and differentiation capacities of these adult stem cells allow for great clinical potential. Because DMSC are cells of ectomesenchymal origin, they reveal a high capacity for complete regeneration of dental pulp, periodontal tissue, and other biomedical applications; their differentiation into other types of cells promotes repair in muscle tissue, cardiac, pancreatic, nervous, bone, cartilage, skin, and corneal tissues, among others, with a high predictability of success. Therefore, stem and progenitor cells, with their exosomes of dental origin and surrounding areas in the oral cavity due to their plasticity, are considered a fundamental pillar in medicine and regenerative dentistry. Tissue engineering (MSCs, scaffolds, and bioactive molecules) sustains and induces its multipotent and immunomodulatory effects. It is of vital importance to guarantee the safety and efficacy of the procedures designed for patients, and for this purpose, more clinical trials are needed to increase the efficacy of several pathologies. Conclusion: From a bioethical and transcendental anthropological point of view, the human person as a unique being facilitates better clinical and personalized therapy, given the higher prevalence of dental and chronic systemic diseases.

Biochemical and functional characterization of skeletal muscle cells differentiated from tonsil-derived mesenchymal stem cells

INTRODUCTION/AIMS

Human tonsils are a readily accessible source of stem cells for the potential treatment of skeletal muscle disorders. We reported previously that tonsil-derived mesenchymal stem cells (TMSCs) can differentiate into skeletal muscle cells (SKMCs), which renders TMSCs promising candidates for cell therapy for skeletal muscle disorders. However, the functional properties of the myocytes differentiated from mesenchymal stem cells have not been clearly evaluated. In this study we investigated whether myocytes differentiated from TMSCs (skeletal muscle cells derived from tonsil mesenchymal stem cells [TMSC-SKMCs]) exhibit the functional characteristics of SKMCs.

METHODS

To test the insulin reactivity of TMSC-SKMCs, the expression of glucose transporter 4 (GLUT4) and phosphatidylinositol 3-kinase/Akt was analyzed after the cells were treated for 30 minutes with 100 nmol/L insulin in normal or high-glucose medium. We also examined whether these cells formed a neuromuscular junction (NMJ) when cocultured with motor neurons, and whether they were stimulated by electrical signals using whole-cell patch clamping.

RESULTS

Skeletal muscle cells derived from tonsil mesenchymal stem cells expressed SKMC markers, such as MYOD, MYH3, MYH8, TNNI1, and TTN, at high levels, and exhibited a multinucleated cell morphology and a myotube-like shape. The expression of the acetylcholine receptor and GLUT4 was confirmed in TMSC-SKMCs. In addition, these cells exhibited insulin-mediated glucose uptake, NMJ formation, and transient changes in cell membrane action potential, all of which are representative functions of human SKMCs.

DISCUSSION

Tonsil-derived mesenchymal stem cells can be functionally differentiated into SKMCs and may have potential for clinical application for the treatment of skeletal muscle disorders.

Matrix Metalloproteinase 1 as a Marker of Tonsil-Derived Mesenchymal Stem Cells to Assess Bone Marrow Cell Migration

BACKGROUND

To achieve optimal bone marrow engraftment during bone marrow transplantation, migration of donor bone marrow cells (BMCs) toward the recipient's bone marrow is critical. Despite the enhanced engraftment of BMCs by co-administration of mesenchymal stem cells (MSCs), the efficiency can be variable depending on MSC donor. The purpose of this study is to examine the functional heterogeneity of tonsil-derived MSCs (TMSCs) and to identify a marker to evaluate efficacy for the enhancement of BMC migration.

METHODS

To examine the donor-to-donor variation of TMSCs in potentiating BMC migration, we isolated TMSCs from 25 independent donors. Transcriptome of TMSCs and proteome of conditioned medium derived from TMSC were analyzed.

RESULTS

Enhanced BMC migration by conditioned medium derived from TMSCs was variable depending on TMSC donor. The TMSCs derived from 25 donors showed distinct expression profiles compared with other cells, including fibroblasts, adipose-derived MSCs and bone marrow-derived MSCs. TMSCs were distributed in two categories: high- and low-efficacy groups for potentiating BMC migration. Transcriptome analysis of TMSCs and proteome profiles of conditioned medium derived from TMSCs revealed higher expression and secretion of matrix metalloproteinase (MMP) 1 in the high-efficacy group. MMP1 knockdown in TMSCs abrogated the supportive efficacy of conditioned medium derived from TMSC cultures in BMC migration.

CONCLUSION

These data suggest that secreted MMP1 can be used as a marker to evaluate the efficacy of TMSCs in enhancing BMC migration. Furthermore, the strategy of analyzing transcriptomes and proteomes of the MSCs may be useful to set the standard for donor variation.

Nucleus-targeted delivery of nitric oxide in human mesenchymal stem cells enhances osteogenic differentiation

Nitric oxide (NO) is an important gaseous signaling molecule in various physiological processes, which functions through interactions with its acceptor molecules located in organelles. NO has an extremely short half-life, making it challenging to experimentally achieve effective NO levels in organelles to study these interactions. Here we developed an organelle-specific, peptide-based NO delivery material that targets the nucleus. NO was attached to the SH group of a cysteine residue inserted into the N-terminus of a cell-penetrating peptide (CPP) conjugated to varying repeats of the nuclear localization signal (NLS), which we denoted NO-CysCPP-NLS, through S-nitrosylation. NO-CysCPP-NLS strongly induced osteogenic differentiation of mesenchymal stem cells. This delivery concept can be extended to cells other than stem cells to elucidate the effects of NO release in the nucleus. Furthermore, conjugation of NO to CysCPP fused to mitochondria- or lysosome-targeting signals can be used to deliver NO to other organelles such as mitochondria and lysosomes, respectively.

Therapeutic effects of mesenchymal stem cells and their derivatives in common skin inflammatory diseases: Atopic dermatitis and psoriasis

Chronic skin inflammatory diseases including atopic dermatitis (AD) and psoriasis have been considered uncontrolled inflammatory responses, which have usually troubled patients around the world. Moreover, the recent method to treat AD and psoriasis has been based on the inhibition, not regulation, of the abnormal inflammatory response, which can induce a number of side effects and drug resistance in long-term treatment. Mesenchymal stem/stromal cells (MSCs) and their derivatives have been widely used in immune diseases based on their regeneration, differentiation, and immunomodulation with few adverse effects, which makes MSCs a promising treatment for chronic skin inflammatory diseases. As a result, in this review, we aim to systematically discuss the therapeutic effects of various resources of MSCs, the application of preconditioning MSCs and engineering extracellular vesicles (EVs) in AD and psoriasis, and the clinical evaluation of the administration of MSCs and their derivatives, which can provide a comprehensive vision for the application of MSCs and their derivatives in future research and clinical treatment.

Tensin Regulates Fundamental Biological Processes by Interacting with Integrins of Tonsil-Derived Mesenchymal Stem Cells

Human tonsil-derived mesenchymal stem cells (TMSCs) have a superior proliferation rate and differentiation potential compared to adipose-tissue-derived MSCs (AMSCs) or bone-marrow-derived MSCs (BMSCs). TMSCs exhibit a significantly higher expression of the tensin3 gene (TNS3) than AMSCs or BMSCs. TNS is involved in cell adhesion and migration by binding to integrin beta-1 (ITG β1) in focal adhesion. Here, we investigated the roles of four TNS isoforms, including TNS3 and their relationship with integrin in various biological processes of TMSCs. Suppressing TNS1 and TNS3 significantly decreased the cell count. The knockdown of TNS1 and TNS3 increased the gene and protein expression levels of p16, p19, and p21. TNS1 and TNS3 also have a significant effect on cell migration. Transfecting with siRNA TNS3 significantly reduced Oct4, Nanog, and Sox-2 levels. Conversely, when TNS4 was silenced, Oct4 and Sox-2 levels significantly increase. TNS1 and TNS3 promote osteogenic and adipogenic differentiation, whereas TNS4 inhibits adipogenic differentiation of TMSCs. TNS3 is involved in the control of focal adhesions by regulating integrin. Thus, TNS enables TMSCs to possess a higher proliferative capacity and differentiation potential than other MSCs. Notably, TNS3 plays a vital role in TMSC biology by regulating ITGβ1 activity.

Basic Fibroblast Growth Factor Induces Cholinergic Differentiation of Tonsil-Derived Mesenchymal Stem Cells

BACKGROUND

Mesenchymal stem cells (MSCs) are considered a potential tool for regenerating damaged tissues due to their great multipotency into various cell types. Here, we attempted to find the appropriate conditions for neuronal differentiation of tonsil-derived MSCs (TMSCs) and expand the potential application of TMSCs for treating neurological diseases.

METHODS

The TMSCs were differentiated in DMEM/F-12 (Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12) supplemented with various neurotrophic factors for 7-28 days to determine the optimal neuronal differentiation condition for the TMSCs. The morphologies as well as the levels of the neural markers and neurotransmitters were assessed to determine neuronal differentiation potentials and the neuronal lineages of the differentiated TMSCs.

RESULTS

Our initial study demonstrated that DMEM/F12 supplemented with 50 ng/mL basic fibroblast growth factor with 10 μM forskolin was the optimal condition for neuronal differentiation for the TMSCs. TMSCs had higher protein expression of neuronal markers, including neuron-specific enolase (NSE), GAP43, postsynaptic density protein 95 (PSD95), and synaptosomal-associated protein of 25 kDa (SNAP25) compared to the undifferentiated TMSCs. Immunofluorescence staining also validated the increased mature neuron markers, NeuN and synaptophysin, in the differentiated TMSCs. The expression of glial fibrillar acidic protein and ionized calcium-binding adaptor molecule 1 the markers of astrocytes and microglia, were also slightly increased. Additionally, the differentiated TMSCs released a significantly higher level of acetylcholine, the cholinergic neurotransmitter, as analyzed by the liquid chromatography-tandem mass spectrometry and showed an enhanced choline acetyltransferase immunoreactivity compared to the undifferentiated cells.

CONCLUSION

Our study suggests that the optimized condition favors the TMSCs to differentiate into cholinergic neuron-like phenotype, which could be used as a possible therapeutic tool in treating certain neurological disorders such as Alzheimer's disease.

Endoplasmin regulates differentiation of tonsil-derived mesenchymal stem cells into chondrocytes through ERK signaling

It is well-known that some species of lizard have an exceptional ability known as caudal autotomy (voluntary self-amputation of the tail) as an anti-predation mechanism. After amputation occurs, they can regenerate their new tails in a few days. The new tail section is generally shorter than the original one and is composed of cartilage rather than vertebrae bone. In addition, the skin of the regenerated tail distinctly differs from its original appearance. We performed a proteomics analysis for extracts derived from regenerating lizard tail tissues after amputation and found that endoplasmin (ENPL) was the main factor among proteins up-regulated in expression during regeneration. Thus, we performed further experiments to determine whether ENPL could induce chondrogenesis of tonsil-derived mesenchymal stem cells (T-MSCs). In this study, we found that chondrogenic differentiation was associated with an increase of ENPL expression by ER stress. We also found that ENPL was involved in chondrogenic differentiation of T-MSCs by suppressing extracellular signal-regulated kinase (ERK) phosphorylation.

Tonsil mesenchymal stem cells-derived extracellular vesicles prevent submandibular gland dysfunction in ovariectomized rats

Dry mouth that occurs after menopause significantly reduces the quality of life of the elderly. The extracellular vesicles derived from mesenchymal stem cells are being studied for application in various pathological conditions in the field of tissue regenerative medicine. This study is to investigate the therapeutic effect on salivary gland dysfunction occurring after ovariectomy using tonsil mesenchymal stem cells (T-MSCs)-derived extracellular vesicles. The rats were divided into the following groups: sham-operated rats (SHAM), rats that underwent ovariectomy (OVX), and rats that underwent OVX surgery and were simultaneously injected with T-MSC-derived extracellular vesicles (OVX+EV). The rats were sacrificed 6 weeks after ovariectomy. Estradiol levels decreased in the OVX group compared with those in the SHAM group. Extracellular vesicles had no effect on estradiol levels or estrogen receptor β expression. The evaluation of pro-inflammatory cytokines, TNF-α and IL-6, increased in the OVX group and decreased in the OVX+EV group. The expressions of collagen I and TGFβI increased in the OVX group but decreased in the OVX+EV group. Moreover, to examine submandibular gland function, AQP5 and α-amylase expressions were downregulated in the OVX group, but improved upon exosome injection. In conclusion, T-MSC-derived extracellular vesicles are useful for the prevented submandibular gland dysfunction that occurs after menopause.

Development of Surgically Transplantable Parathyroid Hormone-Releasing Microbeads

Hypoparathyroidism is an endocrine disorder that occurs because of the inability to produce parathyroid hormone (PTH) effectively. Previously, we reported the efficacy of tonsil-derived mesenchymal stem cells (TMSCs) differentiated into parathyroid-like cells for the treatment of hypoparathyroidism. Here, we investigated the feasibility of three-dimensional structural microbeads fabricated with TMSCs and alginate, a natural biodegradable polymer, to treat hypoparathyroidism. Alginate microbeads were fabricated by dropping a 2% (w/v) alginate solution containing TMSCs into a 5% CaCl2 solution and then differentiated into parathyroid-like cells using activin A and sonic hedgehog for 7 days. The protein expression of PTH, a specific marker of the parathyroid gland, was significantly higher in differentiated alginate microbeads with TMSCs (Al-dT) compared with in undifferentiated alginate microbeads with TMSCs. For in vivo experiments, we created the hypoparathyroidism animal model by parathyroidectomy (PTX) and implanted alginate microbeads in the dorsal interscapular region. The PTX rats with Al-dT (PTX+Al-dT) showed the highest survival rate and weight change and a gradual increase in serum intact PTH levels. We also detected a higher expression of PTH in retrieved tissues of PTX+Al-dT using immunofluorescence analysis. This study demonstrates that alginate microbeads are potential a new tool as a surgically scalable therapy for treating hypoparathyroidism.

Procollagen C-Endopeptidase Enhancer 2 Secreted by Tonsil-Derived Mesenchymal Stem Cells Increases the Oxidative Burst of Promyelocytic HL-60 Cells

Simple Summary

Tonsil-derived mesenchymal stem cells (TMSCs) improved the reactive oxygen species (ROS) production in human promyelocytic leukaemia cells (HL-60) differentiated into neutrophil-like cells (dHL-60). TMSC-induced enhancement of ROS generation in dHL-60 cells was different depending on the TMSC donor. Comparison of RNA-sequencing data between high and low potentiating TMSC groups for ROS generation in dHL-60 cells showed elevated expressions of four genes: secreted frizzled-related protein 4, mesenteric estrogen-dependent adipogenesis, microfibrillar associated protein 5, and procollagen C-endopeptidase enhancer 2 (PCOLCE2). Real-time PCR and Western blotting confirmed high levels of PCOLCE2 in the high potentiating TMSC group for ROS generation in dHL-60 cells. In addition, knockdown of PCOLCE2 in TMSCs reduced the enhancing efficacy of TMSCs regarding ROS generation in dHL-60 cells. Finally, treatment of recombinant PCOLCE2 protein augmented ROS production in dHL-60 cells with concomitant increases of NADPH oxidase (NOX) 3, NOX4, NOX5, and dual oxidase 2. Taken together, this study showed that PCOLCE2 levels in TMSCs could be used to select TMSCs with the high potentiating ability for ROS generation in neutrophils, and both TMSCs and PCOLCE2 may have the potential to enhance a frontline defence by increasing the efficiency of ROS generation in neutrophils.

Abstract

Reactive oxygen species (ROS) generated by neutrophils provide a frontline defence against invading pathogens. We investigated the supportive effect of tonsil-derived mesenchymal stem cells (TMSCs) on ROS generation from neutrophils using promyelocytic HL-60 cells. Methods: Differentiated HL-60 (dHL-60) cells were cocultured with TMSCs isolated from 25 independent donors, and ROS generation in dHL-60 cells was measured using luminescence. RNA sequencing and real-time PCR were performed to identify the candidate genes of TMSCs involved in augmenting the oxidative burst of dHL-60 cells. Transcriptome analysis of TMSCs derived from 25 independent donors revealed high levels of procollagen C-endopeptidase enhancer 2 (PCOLCE2) in TMSCs, which were highly effective in potentiating ROS generation in dHL-60 cells. In addition, PCOLCE2 knockdown in TMSCs abrogated TMSC-induced enhancement of ROS production in dHL-60 cells, indicating that TMSCs increased the oxidative burst in dHL-60 cells via PCOLCE2. Furthermore, the direct addition of recombinant PCOLCE2 protein increased ROS production in dHL-60 cells. These results suggest that PCOLCE2 secreted by TMSCs may be used as a therapeutic candidate to enhance host defences by increasing neutrophil oxidative bursts. PCOLCE2 levels in TMSCs could be used as a marker to select TMSCs exhibiting high efficacy for enhancing neutrophil oxidative bursts.

Pralatrexate Sustainably Released from Polypeptide Thermogel Is Effective for Chondrogenic Differentiation of Mesenchymal Stem Cells

Folic acid was reported to significantly improve chondrogenic differentiation of mesenchymal stem cells. In a similar mechanism of action, we investigated clinically approved antifolates by the U.S. Food and Drug Administration as chondrogenic-promoting compounds for tonsil-derived mesenchymal stem cells. A poly(ethylene glycol)-poly(l-alanine) thermogelling system was used as a three-dimensional cell culture matrix, where stem cells and antifolates could be incorporated simultaneously during a heat-induced in situ sol-to-gel transition. The antifolates could be supplied over several days by the sustained release of the drug from the thermogel. Initially, seven antifolates were prescreened based on cell viability and expression of a typical chondrogenic biomarker of type II collagen (COL II) at the mRNA level. Then, dapsone, pralatrexate, and trimethoprim were selected as candidate compounds in the second round screening, and detailed studies were carried out on the mRNA and protein expression of various chondrogenic biomarkers including COL II, SRY box transcription factor 9, and aggrecan. Three-dimensional cultures of stem cells in the thermogel in the absence of a chondrogenic promoter compound and in the presence of kartogenin (KGN) were performed as a negative control and positive control, respectively. The chondrogenic biomarkers were significantly increased in the selected antifolate-incorporating systems compared to the negative control system, without an increase in type I collagen (an osteogenic biomarker) expression. Pralatrexate was the best compound for inducing chondrogenic differentiation of the stem cells, even better than the positive control (KGN). Nuclear translocation of the core-binding factor β subunit (CBFβ) and enhanced nuclear runt-related transcription factor 1 (RUNX1) by antifolate treatment suggested that the chondrogenesis-enhancing mechanism is mediated by CBFβ and RUNX1. An in silico modeling study confirmed the mechanism by proving the high binding affinity of pralatrexate to a target protein of filamin A compared with other antifolate candidates. To conclude, pralatrexate was rediscovered as a lead compound, and the polypeptide thermogel incorporating pralatrexate and mesenchymal stem cells can be a very effective system in promoting chondrogenic differentiation of stem cells and might be used in injectable tissue engineering for cartilage repair.

Folic acid pretreatment and its sustained delivery for chondrogenic differentiation of MSCs

Dietary uptake of folic acid (FA) improves cartilage regeneration. In this work, we discovered that three days of FA treatment is highly effective for promoting chondrogenic differentiation of tonsil-derived mesenchymal stem cells (TMSCs). In a three-dimensional pellet culture, the levels of typical chondrogenic biomarkers, sulfated glycosaminoglycan, proteoglycan, type II collagen (COL II), SRY box transcription factor 9 (SOX 9), cartilage oligomeric matrix protein (COMP), and aggrecan (ACAN) increased significantly in proportion to FA concentration up to 30 μM. At the mRNA expression level, COL II, SOX 9, COMP, and ACAN increased 3.6-6.0-fold with FA treatment at 30 μM compared with the control system that did not receive FA treatment, and the levels with FA treatment were 1.6-2.5 times greater than those in the kartogenin-treated positive control system. FA treatment did not increase type I collagen α1 (COL I α1), an osteogenic biomarker which is a concern with most chondrogenic promoters. At the high FA concentration of 100 μM, significant decreases in chondrogenic biomarkers were observed, which might be related to DNA methylation. A thermogel system incorporating TMSCs and FA provided sustained release of FA over several days, similar to the FA treatment. The thermogel system confirmed the efficacy of FA in promoting chondrogenic promotion of TMSCs. The increased nuclear translocation of core-binding factor β subunit (CBFβ) and the runt-related transcription factor 1 (RUNX1) expression after FA treatment, together with molecular docking studies, suggest that the chondrogenic enhancement mechanism of FA is mediated by CBFβ and RUNX1.

Influence of mechanical and TGF-β3 stimulation on the tenogenic differentiation of tonsil-derived mesenchymal stem cells

Background

Organogenesis from tonsil-derived mesenchymal cells (TMSCs) has been reported, wherein tenogenic markers are expressed depending on the chemical stimulation during tenogenesis. However, there are insufficient studies on the mechanical strain stimulation for tenogenic cell differentiation of TMSCs, although these cells possess advantages as a cell source for generating tendinous tissue. The purpose of this study was to investigate the effects of mechanical strain and transforming growth factor-beta 3 (TGF-β3) on the tenogenic differentiation of TMSCs and evaluate the expression of tendon-related genes and extracellular matrix (ECM) components, such as collagen.

Results

mRNA expression of tenogenic genes was significantly higher when the mechanical strain was applied than under static conditions. Moreover, mRNA expression of tenogenic genes was significantly higher with TGF-β3 treatment than without. mRNA expression of osteogenic and chondrogenic genes was not significantly different among different mechanical strain intensities. In cells without TGF-β3 treatment, double-stranded DNA concentration decreased, while the amount of normalized collagen increased as the intensity of mechanical strain increased.

Conclusions

Mechanical strain and TGF-β3 have significant effects on TMSC differentiation into tenocytes. Mechanical strain stimulates the differentiation of TMSCs, particularly into tenocytes, and cell differentiation, rather than proliferation. However, a combination of these two did not have a synergistic effect on differentiation. In other words, mechanical loading did not stimulate the differentiation of TMSCs with TGF-β3 supplementation. The effect of mechanical loading with TGF-β3 treatment on TMSC differentiation can be manipulated according to the differentiation stage of TMSCs. Moreover, TMSCs have the potential to be used for cell banking, and compared to other mesenchymal stem cells, they can be procured from patients via less invasive procedures.

Association between Klebsiella pneumoniae and ankylosing spondylitis: A systematic review and meta-analysis

AIM

The aim of this study is to evaluate the association between Klebsiella pneumoniae infection and ankylosing spondylitis (AS).

METHOD

Five electronic databases, PubMed, Embase, Medline, Web of Science, and Scopes, were searched until September 29, 2021. Cohort and case-control studies that assessed the association between K. pneumoniae infection and AS were included. Pooled odds ratio (OR) was selected to show the effect size. Subgroup analysis (active or inactive AS) and 2 forms of sensitivity analysis were conducted. All statistical analyses were conducted by using STATA 12.0.

RESULTS

There were 25 case-control studies finally included, including 8 studies concerning presence of K. pneumoniae in feces, and 17 studies concerning serum antibody (immunoglobulin [Ig]G, IgM, IgA) against K. pneumoniae. The results suggested that when compared with healthy people, presence of K. pneumoniae in feces was associated with AS (OR: 5.65; 95% CI: 1.68-19.00). Similarly, when compared with healthy people, higher positive rates of IgA (OR: 6.28; 95% CI: 3.32-11.91) and IgG (OR: 5.22; 95% CI: 1.36-19.99) were observed. Subgroup analyses suggested that association between K. pneumoniae and AS appears stronger in active AS.

CONCLUSION

When compared with healthy people, a significantly higher positive rate of K. pneumoniae in feces, serum IgA and IgG were observed in patients with AS, suggesting that K. pneumoniae probably plays a crucial role in the occurrence of AS. The findings in this study need further prospective investigations for confirmation.

Promotion of Platelet Production by Co-Transplantation of Mesenchymal Stem Cells in Bone Marrow Transplantation

BACKGROUND

Therapeutic strategies that can promote platelet production are in demand to enhance clinical outcomes of bone marrow transplantation (BMT). Our research group has studied human tonsil-derived mesenchymal stem cells (T-MSCs) and their effectiveness in promoting bone marrow (BM) engraftment. Here, we analyzed the effects of T-MSCs on platelet production and hemostasis.

METHODS

Donor BM cells (BMCs) were isolated from C57BL/6 mice and transplanted with or without T-MSCs to BALB/c recipient mice. Mice were sacrificed and blood cells were counted using an Auto Hematology Analyzer. Femur sections were stained with CD41 antibody to analyze megakaryocytes in the BM. Growth factor secretion from MSCs was analyzed using the Quantibody Array. Effects of T-MSC conditioned medium (CM) on megakaryopoiesis were investigated using the MegaCult assay. In a mouse model of BMT, T-MSC CM was injected with or without anti-placental growth factor (α-PlGF) blocking antibody, and blood cell numbers and coagulation were analyzed.

RESULTS

T-MSC co-transplantation increased percent survival of BMT mice. Platelet numbers were significantly lower in the BMC-only group, whereas T-MSC co-transplantation restored circulating platelets to levels similar to those of the control group. Significantly reduced numbers of CD41 + megakaryocytes in Bu-Cy and BMC groups were increased by T-MSC co-transplantation. PlGF secretion from T-MSCs were detected and enhanced megakaryopoiesis, platelet production, and coagulation by T-MCS CM were disrupted in the presence of the α-PlGF blocking antibody.

CONCLUSION

We demonstrated the effectiveness of T-MSC co-transplantation in promoting platelet production and coagulation after BMT. These findings highlight the potential therapeutic relevance of T-MSCs for preventing thrombocytopenia after BMT.

Translational and Clinical Applications of Dental Stem Cell-Derived Exosomes

Mesenchymal stem cells (MSCs) are promising seed cells in tissue repair and regeneration due to their featured properties of self-renewal and multipotency. However, a growing body of evidence has demonstrated that MSCs exert biological functions mainly through secreting exosomes. Exosomes, which contain RNA, proteins, lipids, and metabolites, are new players in regulating many fundamental processes and play important roles in regenerative medicine. Exosomes not only mimic the effects of their parent cells but also possess many advantages such as high drug loading capacity, low immunogenicity, excellent biocompatibility, and low side effects. Currently, a total of 6 different dental stem cells (DSCs) including dental pulp stem cells (DPSCs), stem cells from exfoliated deciduous teeth (SHEDs), periodontal ligament stem cells (PDLSCs), dental follicle progenitor cells (DFPCs), stem cells from apical papilla (SCAPs) and gingival mesenchymal stem cells (GMSCs) have been isolated and identified. DSC-derived exosomes (DSC-Exos) are actively involved in intercellular communication, anti-inflammation, osteogenesis, angiogenesis, immunomodulation, nurturing neurons, and promoting tumor cell apoptosis. In this review, we will critically review the emerging role and clinical application potential of DSC-Exos.

Extracellular vesicles from tonsil‑derived mesenchymal stromal cells show anti‑tumor effect via miR‑199a‑3p

Mesenchymal stem cells (MSCs) are mesoderm‑originated adult SCs that possess multidirectional differentiation potential. MSCs migrate to injured tissue and secrete a range of paracrine factors that induce regeneration in damaged tissue and exert immune modulation. Because tumor progression is dependent on cross‑talk between the tumor and its microenvironment, MSCs also produce extracellular vesicles (EVs) that mediate information transfer in the tumor microenvironment. However, the effect of MSC‑derived EVs on tumor development and progression is still controversial. To date, tonsil‑derived MSCs (T‑MSCs) have been shown to possess all the defined characteristics of MSCs and show distinctive features of differential potential and immune modulation. To observe the effect of soluble mediators from T‑MSCs on tumor growth, human liver cancer cell line (HepG2) cells were injected into nude mice and HepG2 cell scratch migration assay was performed using conditioned medium (CM) of T‑MSCs. T‑MSC CM inhibited tumor growth and progression and it was hypothesized that EVs from T‑MSCs could inhibit tumor progression. microRNA (miRNA or miR) sequencing using five different origins of T‑MSC‑derived EVs was performed and highly expressed miRNAs, such as miR‑199a‑3p, miR‑214‑3p, miR‑199a‑5p and miR‑199b‑5p, were selected. T‑MSCs inhibited tumor growth and HepG2 cell migration, potentially via miR‑199a‑3p targeting CD151, integrin α3 and 6 in HepG2 cells.

Three-dimensional culture method enhances the therapeutic efficacies of tonsil-derived mesenchymal stem cells in murine chronic colitis model

Tonsil-derived mesenchymal stem cells (TMSCs) showed therapeutic effects on acute and chronic murine colitis models, owing to their immunomodulatory properties; therefore, we evaluated enhanced therapeutic effects of TMSCs on a murine colitis model using three-dimensional (3D) culture method. The expression of angiogenic factors, VEGF, and anti-inflammatory cytokines, IL-10, TSG-6, TGF-β, and IDO-1, was significantly higher in the 3D-TMSC-treated group than in the 2D-TMSC-treated group (P < 0.05). At days 18 and 30 after inducing chronic colitis, disease activity index scores were estimated to be significantly lower in the 3D-TMSC-treated group than in the colitis control (P < 0.001 and P < 0.001, respectively) and 2D-TMSC-treated groups (P = 0.022 and P = 0.004, respectively). Body weight loss was significantly lower in the 3D-TMSC-treated group than in the colitis control (P < 0.001) and 2D-TMSC-treated groups (P = 0.005). Colon length shortening was significantly recovered in the 3D-TMSC-treated group compared to that in the 2D-TMSC-treated group (P = 0.001). Histological scoring index was significantly lower in the 3D-TMSC-treated group than in the 2D-TMSC-treated group (P = 0.002). These results indicate that 3D-cultured TMSCs showed considerably higher therapeutic effects in a chronic murine colitis model than those of 2D-cultured TMSCs via increased anti-inflammatory cytokine expression.

Size and Shape Control of Ice Crystals by Amphiphilic Block Copolymers and Their Implication in the Cryoprotection of Mesenchymal Stem Cells

Precise control over the size and shape of ice crystals is a key factor to consider in designing antifreezing and cryoprotecting molecules for cryopreservation of cells. Here, we report that a poly(ethylene glycol)-poly(l-alanine) (PEG-PA) block copolymer exhibits excellent cryoprotecting properties for stem cells and antifreezing properties for water. As the molecular weight of PA increased from 500, 760, and 1750 Da (P1, P2, and P3) at the same PEG molecular weight of 5000 Da, the β-sheet content decreased and α-helix content increased. Comparing P2 (PEG-PA; 5000-760) and P4 (PEG-PA: 1000-750), β-sheets increased as the PEG block length decreased. The critical micelle concentration of the PEG-PA block copolymers was in a range of 0.5-3.0 mg/mL and was proportional to the hydrophobicity of the PEG-PA block copolymers. The P1, P2, and P3 self-assembled into spherical micelles, whereas P4 formed micelles with cylindrical morphology. The difference in the block copolymer structure affected ice recrystallization inhibition (IRI) activity and cryopreservation of cells. IRI activity was assayed via mean largest grain size (MLGS), and interactions between polymers and ice crystal surfaces were studied by dynamic ice-shaping studies. The MLGS decreased to 58 → 53 → 45 → 35 → 23% of that of PBS, as the polymer (PEG-PA 5000-500) concentration increased from 0.0 (PBS; control) → 1.0 → 5.0 → 10 → 30 → 50 mg/mL. The MLGS of PEG 5k solutions (negative control) decreased to 74 → 71 → 64 → 44 → 37% of that of PBS in the same concentration range. P3 and P4 with a longer hydrophobic PA block developed elongated ice crystals at above 30 mg/mL. The dynamic ice-shaping study exhibited that ice crystals became needle-shaped, as the hydrophobicity of the polymer increased as in P2-P4. The cell recovery in the P1 system after cryopreservation at -196 °C for 7 days was 87% of that of the dimethyl sulfoxide (DMSO) 10% system (positive control). The cell recovery was 48% for the P2 system and drastically decreased to less than 30% of that of the DMSO 10% system in the P3, P4, PEG 5k, PEG 1k, PVA 80H, and PVA 100H systems. Current studies suggest that IRI activity, round ice crystal shaping, and membrane stabilization activity of P1 cooperatively provide excellent cell recovery among the candidate systems. Recovered stem cells exhibited excellent proliferation and multilineage differentiation into osteocytes, chondrocytes, and adipocytes. To conclude, the PEG-PA (5000-500) block copolymer is suggested to be a promising antifreezing cryoprotectant for stem cells.

A cell surface-reducing microenvironment induces early osteogenic commitment

Stem cell-based therapy has been highlighted as a potential avenue to promote tissue regeneration, where stimulation of stem cells to differentiate into the targeted cell type is essential. One of the factors that induce stem cells to differentiate is their surrounding microenvironment. In this study, the correlation between mild reductant and early osteogenic commitment was evaluated. A cell surface-reducing microenvironment significantly silenced the transforming growth factor (TGF)-β signaling pathway of mesenchymal stem cells (MSCs), followed by increased focal adhesion and inhibition of cell membrane protein dimerization. Furthermore, in vivo transplantation of MSCs exposed to the reducing microenvironment resulted in an early osteogenic commitment and neobone formation. Thus, these results highlight the potential of cell surface-reducing microenvironment to influence early osteogenic commitment.

Therapeutic Effects of Tonsil-derived Mesenchymal Stem Cells in an Atopic Dermatitis Mouse Model

BACKGROUND/AIM

Mesenchymal stem cells (MSCs) have been suggested as an alternative therapeutic option in atopic dermatitis. Palatine tonsils are lymphoepithelial tissue located around the oropharynx and have been proposed as one of the important alternative sources of MSCs. The purpose of this study was to evaluate the protective and therapeutic effects of tonsil-derived MSCs (TMSCs) in a 2,4-dinitrofluorobenzene (DNFB)-induced mouse model of atopic dermatitis (AD).

MATERIALS AND METHODS

The effect of TMSCs was evaluated in 20 C57BL/6J mice that were randomly divided into four groups (normal, DNFB-PBS, DNFB-TMSC7, and DNFB-TMSC16 group). TMSCs were subcutaneously injected into DNFB-sensitized mice on day 7 (DNFB-TMSC7 group) and day 16 (DNFB-TMSC16 group). Several parameters of inflammation were assessed.

RESULTS

Subcutaneously injected TMSCs significantly improved the inflammatory symptoms in a DNFB-induced AD model mice, particularly showing therapeutic effects rather than protective effects. TMSC treatment inhibited T-cell-mediated inflammatory responses by decreasing the levels of IL-6, IL-1β, TNF-α (Th1 cell marker), IL-4 (Th2 cell marker), and B-cell-mediated serum IgE. In contrast, TMSCs enhanced the anti-inflammatory cytokine TGF-β.

CONCLUSION

In vitro and in vivo results suggest that TMSC treatment improved inflammatory skin lesions in the DNFB-induced AD mice model via immunomodulatory effects of the TMSCs. TMSCs inhibit T-cell and B-cell mediated responses, and enhance the anti-inflammatory responses.

Therapeutic Effect of IL1β Priming Tonsil Derived-Mesenchymal Stem Cells in Osteoporosis

BACKGROUND

Stem cell therapies can be a new therapeutic strategy that may rebalance anabolic and anti-resorptive effects in osteoporosis patients. Tonsil-derived mesenchymal stem cells (TMSCs) can be an alternative therapeutic source for chronic degenerative diseases including osteoporosis. MSCs acquire immune regulatory function under the inflammatory cytokines. Since interleukin (IL) 1β is known to be one of inflammatory cytokines involved in osteoporosis progression, treatment of IL1β with TMSCs may enhance immunomodulatory function and therapeutic effects of TMSCs in osteoporosis.

METHODS

For IL1β priming, TMSCs were cultured in the presence of the medium containing IL1β for 1 day. Characteristics of IL1β priming TMSCs such as multipotent differentiation properties, anti-inflammatory potential, and suppression of osteoclast differentiation were assessed in vitro. For in vivo efficacy study, IL1β priming TMSCs were intravenously infused twice with ovariectomized (OVX) osteoporosis mouse model, and blood serum and bone parameters from micro computed tomography images were analyzed.

RESULTS

IL1β priming TMSCs had an enhanced osteogenic differentiation and secreted factors that regulate both osteoclastogenesis and osteoblastogenesis. IL1β priming TMSCs also suppressed proliferation of peripheral blood mononuclear cells (PBMCs) and decreased expression of Receptor activator of nuclear factor kappa-Β ligand (RANKL) in PHA-stimulated PBMCs. Furthermore, osteoclast specific genes such as Nuclear factor of activated T cells c1 (NFATc1) were effectively down regulated when co-cultured with IL1β priming TMSCs in RANKL induced osteoclasts. In OVX mice, IL1β priming TMSCs induced low level of serum RANKL/osteoprotegerin (OPG) ratio on the first day of the last administration. Four weeks after the last administration, bone mineral density and serum Gla-osteocalcin were increased in IL1β priming TMSC-treated OVX mice. Furthermore, bone formation and bone resorption markers that had been decreased in OVX mice with low calcium diet were recovered by infusion of IL1β priming TMSCs.

CONCLUSION

IL1β priming can endow constant therapeutic efficacy with TMSCs, which may contribute to improve bone density and maintain bone homeostasis in postmenopausal osteoporosis. Therefore, IL1β priming TMSCs can be a new therapeutic option for treating postmenopausal osteoporosis.

Tonsil-derived mesenchymal stem cells enhance allogeneic bone marrow engraftment via collagen IV degradation

BACKGROUND

Co-transplantation of bone marrow cells (BMCs) and mesenchymal stem cells (MSCs) is used as a strategy to improve the outcomes of bone marrow transplantation. Tonsil-derived MSCs (TMSCs) are a promising source of MSCs for co-transplantation. Previous studies have shown that TMSCs or conditioned media from TMSCs (TMSC-CM) enhance BMC engraftment. However, the factors in TMSCs that promote better engraftment have not yet been identified.

METHODS

Mice were subjected to a myeloablative regimen of busulfan and cyclophosphamide, and the mRNA expression in the bone marrow was analyzed using an extracellular matrix (ECM) and adhesion molecule-targeted polymerase chain reaction (PCR) array. Nano-liquid chromatography with tandem mass spectrometry, real-time quantitative PCR, western blots, and enzyme-linked immunosorbent assays were used to compare the expression levels of metalloproteinase 3 (MMP3) in MSCs derived from various tissues, including the tonsils, bone marrow, adipose tissue, and umbilical cord. Recipient mice were conditioned with busulfan and cyclophosphamide, and BMCs, either as a sole population or with control or MMP3-knockdown TMSCs, were co-transplanted into these mice. The effects of TMSC-expressed MMP3 were investigated. Additionally, Enzchek collagenase and Transwell migration assays were used to confirm that the collagenase activity of TMSC-expressed MMP3 enhanced BMC migration.

RESULTS

Mice subjected to the myeloablative regimen exhibited increased mRNA expression of collagen type IV alpha 1/2 (Col4a1 and Col4a2). Among the various extracellular matrix-modulating proteins secreted by TMSCs, MMP3 was expressed at higher levels in TMSCs than in other MSCs. Mice co-transplanted with BMCs and control TMSCs exhibited a higher survival rate, weight recovery, and bone marrow cellularity compared with mice co-transplanted with BMCs and MMP3-knockdown TMSCs. Control TMSC-CM possessed higher collagenase activity against collagen IV than MMP3-knockdown TMSC-CM. TMSC-CM also accelerated BMC migration by degrading collagen IV in vitro.

CONCLUSIONS

Collectively, these results indicate that TMSCs enhance BMC engraftment by the secretion of MMP3 for the modulation of the bone marrow extracellular matrix.

IDO and CD40 May Be Key Molecules for Immunomodulatory Capacity of the Primed Tonsil-Derived Mesenchymal Stem Cells

Background: Tonsil-derived mesenchymal stem cells (T-MSCs) were reported to have suppressive effect on T cells, yet much remains unknown about the underlying mechanisms supporting this effect. We investigated the underlying mechanism of the immunomodulatory effect of T-MSCs on immune cell proliferation and cytokine production. Methods: We isolated T-MSCs from human palatine tonsil and evaluated the immunomodulatory capacity using RT-PCR, ELISA, and flow cytometry. Additionally, we assessed the expression of various soluble factors and several costimulatory molecules to detect the priming effect on T-MSCs. Results: T-MSCs significantly inhibited the immune cell proliferation and cytokine expression (TNF-α and IFN-γ) in the direct co-culture, but there was no suppressive effect in indirect co-culture. Additionally, we detected a remarkably higher expression of indoleamine 2,3-dioxygenase (IDO) in the primed T-MSCs having co-expression CD40. Moreover, immune cells or CD4⁺ T cells showed lower TNF-α, IFN-γ, and IL-4 expression when the primed T-MSC were added; whereas those findings were reversed when the inhibitor for IDO (not IL-4) or CD40 were added. Furthermore, T-bet and GATA3 levels were significantly decreased in the co-cultures of the primed T-MSCs and CD4⁺ T cells; whereas those findings were reversed when we added the neutralizing anti-CD40 antibody. Conclusions: Primed T-MSCs expressing IDO and CD40 may have immunomodulatory capacity via Th1-mediated and Th2-mediated immune response.

Octanoyl glycol chitosan enhances the proliferation and differentiation of tonsil-derived mesenchymal stem cells

Biofunctional polymers have been widely used to enhance the proliferation and functionality of stem cells. Here, we report the development of a new biofunctional polymer, octanoyl glycol chitosan (OGC), and demonstrate its effects on the cell cycle and stem cell function using tonsil-derived mesenchymal stem cells (TMSCs). OGC treatment (100 μg/mL) significantly increased the proliferation of TMSCs, which could be attributed to cyclin D1 up-regulation in the G1 phase of the cell cycle. Additionally, OGC enhanced the ability of TMSCs to differentiate into adipocytes, chondrocytes, and osteoblasts. Taken together, this new biofunctional polymer, OGC, can promote stemness and osteogenesis, as well as induce stem cell proliferation by enhancing the intracellular metabolic rate and regulating the cell cycle. Thus, in the future, OGC could be a potential therapeutic additive for improving stem cell function.

Transient receptor potential vanilloid 2 mediates the inhibitory effect of far-infrared irradiation on adipogenic differentiation of tonsil-derived mesenchymal stem cells

AIMS

Far-infrared (FIR) irradiation inhibits adipogenic differentiation of tonsil-derived mesenchymal stem cells (TMSCs) by activating Ca²⁺-dependent protein phosphatase 2B (PP2B), but it stimulates osteogenic differentiation in a PP2B-independent pathway. We investigated the potential involvement of transient receptor potential vanilloid (TRPV) channels, a well-known Ca²⁺-permeable channel, in the effects of FIR irradiation on adipogenic or osteogenic differentiation of TMSCs.

METHODS

TMSCs, in the absence or presence of activators or inhibitors, were exposed to FIR irradiation followed by adipogenic or osteogenic differentiation, which was assessed using Oil red O or Alizarin red S staining, respectively. RT-PCR, qRT-PCR, and Western blotting were used to determine gene and protein expression of calcium channels and adipocyte-specific markers.

RESULTS

Treatment with the calcium ionophore ionomycin simulated the inhibitory effect of FIR irradiation on adipogenic differentiation but had no effect on osteogenic differentiation, indicating the involvement of intracellular Ca²⁺ in adipogenic differentiation. Inhibition of pan-TRP channels using ruthenium red reversed the FIR irradiation-induced inhibition of adipogenic differentiation. Among the TRP channels tested, inhibition of the TRPV2 channel by tranilast or siRNA against TRPV2 attenuated the inhibitory effect of FIR irradiation on adipogenic differentiation, accompanied by a decrease in intracellular Ca²⁺ levels. By contrast, activation of the TRPV2 channel by probenecid simulated FIR irradiation-induced inhibition of adipogenic differentiation. Expectedly, the stimulatory effect of FIR irradiation on osteogenic differentiation was independent of the TRPV2 channel.

CONCLUSION

Our data demonstrate that the TRPV2 channel is a sensor/receptor for the inhibited adipogenic differentiation of TMSCs associated with FIR irradiation.

Bioinspired inorganic nanoparticles and vascular factor microenvironment directed neo-bone formation

Various strategies have been explored to stimulate new bone formation. These strategies include using angiogenic stimulants in combination with inorganic biomaterials. Neovascularization during the neo-bone formation provides nutrients along with bone-forming minerals. Therefore, it is crucial to design a bone stimulating microenvironment composed of both pro-angiogenic and osteogenic factors. In this respect, human vascular endothelial growth factor (hVEGF) has been shown to promote blood vessel formation and bone formation. Furthermore, in recent years, whitlockite (WH), a novel phase of magnesium-containing calcium phosphate derivatives that exist in our bone tissue, has been synthesized and applied in bone tissue engineering. In this study, our aim is to explore the potential use of hVEGF and WH for bone tissue engineering. Our study demonstrated that hVEGF and a WH microenvironment synergistically stimulated osteogenic commitment of mesenchymal stem cells both in vitro and in vivo.

sEVs from tonsil-derived mesenchymal stromal cells alleviate activation of hepatic stellate cells and liver fibrosis through miR-486-5p

Mesenchymal stromal cells (MSCs) are considered as a promising therapeutic tool for liver fibrosis, a main feature of chronic liver disease. Because small extracellular vesicles (sEVs) harboring a variety of proteins and RNAs are known to have similar functions with their derived cells, MSC-derived sEVs carry out the regenerative capacities of MSCs. Human tonsil-derived MSCs (T-MSCs) are reported as a novel source of MSCs, but their effects on liver fibrosis remain unclear. In the present study, we investigated the effects of T-MSC-derived sEVs on liver fibrosis. The expression of profibrotic genes decreased in human primary hepatic stellate cells (pHSCs) co-cultured with T-MSCs. Treatment of T-MSC-sEVs inactivated human and mouse pHSCs. Administration of T-MSC-sEVs ameliorated hepatic injuries and fibrosis in chronically damaged liver induced by carbon tetrachloride (CCl₄). miR-486-5p highly enriched in T-MSC-sEVs targeting the hedgehog receptor, smoothened (Smo), was upregulated, whereas Smo and Gli2, the hedgehog target gene, were downregulated in pHSCs and liver tissues treated with T-MSC-sEVs or miR-486-5p mimic, indicating that sEV-miR-486 inactivates HSCs by suppressing hedgehog signaling. Our results showed that T-MSCs attenuate HSC activation and liver fibrosis by delivering sEVs, and miR-486 in the sEVs inactivates hedgehog signaling, suggesting that T-MSCs and their sEVs are novel anti-fibrotic therapeutics for treating chronic liver disease.

TNF-α Priming Elicits Robust Immunomodulatory Potential of Human Tonsil-Derived Mesenchymal Stem Cells to Alleviate Murine Colitis

Mesenchymal stem cells (MSCs) have been spotlighted in the field of cell therapies as a promising tool for the treatment of intractable inflammatory diseases. However, their therapeutic potency still shows a gap between preclinical and clinical settings, and distinctive characteristics of specific tissue-derived MSCs and definitive ways to maximize their beneficial functions have not been fully elucidated yet. We previously identified the unique MSCs population from human palatine tonsil (TMSCs) and revealed their superior properties in proliferation and ROS regulation. Based on these findings, we explored further characteristics of TMSCs particularly focused on immunomodulatory function. We found the merit of TMSCs as a therapeutic agent that retains favorable MSCs properties until relatively late passages and revealed that pre-treatment of TNF-α can enhance the immunomodulatory abilities of TMSCs through the upregulation of the PTGS2/PGE₂ axis. TMSCs primed with TNF-α effectively restrained the proliferation and differentiation of T lymphocytes and macrophages in vitro, and more interestingly, these TNF-α-licensed TMSCs exhibited significant prophylactic and therapeutic efficacy in a murine model of autoimmune-mediated acute colitis via clinical and histopathological assessment compared to unprimed naïve TMSCs. These findings provide novel insight into the optimization and standardization of MSCs-based anti-inflammatory therapies, especially targeting inflammatory bowel disease (IBD).

A Novel Method to Differentiate Tonsil-Derived Mesenchymal Stem Cells In Vitro into Estrogen-Secreting Cells

BACKGROUND

The advantages of tonsil-derived mesenchymal stem cells (TMSCs) over other mesenchymal stem cells (MSCs) include higher proliferation rates, various differentiation potentials, efficient immune-modulating capacity, and ease of obtainment. Specifically, TMSCs have been shown to differentiate into the endodermal lineage. Estrogen deficiency is a major cause of postmenopausal osteoporosis and is associated with higher incidences of ischemic heart disease and cerebrovascular attacks during the postmenopausal period. Therefore, stem cell-derived, estrogen-secreting cells might be used for estrogen deficiency.

METHODS

Here, we developed a novel method that utilizes retinoic acid, insulin-like growth factor-1, basic fibroblast growth factor, and dexamethasone to evaluate the differentiating potential of TMSCs into estrogen-secreting cells. The efficacy of the novel differentiating method for generation of estrogen-secreting cells was also evaluated with bone marrow- and adipose tissue-derived MSCs.

RESULTS

Incubating TMSCs in differentiating media induced the gene expression of cytochrome P450 19A1 (CYP19A1), which plays a key role in estrogen biosynthesis, and increased 17β-estradiol secretion upon testosterone addition. Furthermore, CYP11A1, CYP17A1, and 3β-hydroxysteroid dehydrogenase type-1 gene expression levels were significantly increased in TMSCs. In bone marrow-derived and adipose tissue-derived MSCs, this differentiation method also induced the gene expression of CYP19A1, but not CYP17A1, suggesting TMSCs are a superior source for estrogen secretion.

CONCLUSION

These results imply that TMSCs can differentiate into functional estrogen-secreting cells, thus providing a novel, alternative cell therapy for estrogen deficiency.

Thermogelling Inclusion Complex System for Fine-Tuned Osteochondral Differentiation of Mesenchymal Stem Cells

How to control osteochondral differentiation of mesenchymal stem cells at a proper stage is a key issue for articular cartilage regeneration. To solve this problem, injectable scaffolds with different chemical functional groups were designed by introducing one equivalent of α-cyclodextrin (α-CD) carboxylate and α-CD phosphate along poly(ethylene glycol)-poly(l-alanine) (PEG-L-PA) block copolymers. Dynamic light scattering, transmission electron microscopy images, and two-dimensional NMR spectra indicated that the PEG-L-PA block copolymers formed inclusion complexes with α-CD derivatives. Aqueous solutions of PEG-L-PA block copolymers (P), α-CD carboxylate/PEG-L-PA block copolymers (PCC), and α-CD phosphate/PEG-L-PA block copolymers (PCP) underwent sol-to-gel transition as the temperature increased. The storage moduli of P, PCC, and PCP gels ranged from 1000 to 1300 Pa at 37 °C. Tonsil-derived mesenchymal stem cells (TMSCs) were incorporated in situ in the gel during thermogelation of P, PCC, and PCP, which became the three-dimensional cell culture systems with different functional groups. After 21 days of incubation of TMSCs in the P, PCC, and PCP systems, the chondrogenic differentiation biomarker of type II collagen significantly increased in the P system, whereas the osteogenic biomarkers of osteocalcin and runt-related transcription factor 2 significantly increased in the PCP system. Both chondrogenic and osteogenic biomarkers were highly expressed in the PCC system. This study proved that thermogelling inclusion complex systems consisting of PEG-L-PA block copolymers and α-CD derivatives could be an excellent injectable matrix for fine-controlling osteochondral differentiation of mesenchymal stem cells.

Optimization of tenocyte lineage-related factors from tonsil-derived mesenchymal stem cells using response surface methodology

BACKGROUND

In order to optimize the tenogenic differentiation of mesenchymal stem cells (MSCs), researchers should consider various factors. However, this requires testing numerous experimental settings, which is costly and time-consuming. We aimed to assess the differential effects of transforming growth factor beta-3 (TGF-β3) on the tenogenesis of tonsil-derived MSCs (T-MSCs) and bone marrow-derived MSCs (BM-MSCs) using response surface methodology (RSM).

METHODS

Bone marrow and tonsillar tissue were collected from four patients; mononuclear cells were separated and treated with 5 or 10 ng/mL of TGF-β3. A full factorial experimental design with a categorical factor of 0 was employed to study the effect of tension based on T-MSCs. Eighty-four trials were fitted with RSM and then used to obtain mathematical prediction models.

RESULTS

Exposure of T-MSCs and BM-MSCs to TGF-β3 increased the expression of scleraxis (SCX), tenomodulin (TNMD), decorin, collagen I, and tenascin C. Expression of most of these factors reached a maximum after 2-3 days of treatment. The model predicted that the values of the tenocyte lineage-related factors assessed would be significantly increased at 2.5 days of culture with 2.7 ng/mL of TGF-β3 for T-MSCs and at 2.3 days of culture regardless of TGF-β3 concentration for BM-MSCs.

CONCLUSIONS

This study demonstrated that the RSM prediction of the culture time necessary for the tenogenic differentiation of T-MSCs and BM-MSCs under TGF-β3 stimulation was similar to the experimentally determined time of peak expression of tenocyte-related mRNAs, suggesting the potential of using the RSM approach for optimization of the culture protocol for tenogenesis of MSCs.

Human Tonsil-Derived Mesenchymal Stromal Cells Maintain Proliferating and ROS-Regulatory Properties via Stanniocalcin-1

Mesenchymal stromal cells (MSCs) from various sources exhibit different potential for stemness and therapeutic abilities. Recently, we reported a unique MSCs from human palatine tonsil (TMSCs) and their superior proliferation capacity compared to MSCs from other sources. However, unique characteristics of each MSC are not yet precisely elucidated. We investigated the role of stanniocalcin-1 (STC1), an anti-oxidative hormone, in the functions of TMSCs. We found that STC1 was highly expressed in TMSC compared with MSCs from bone marrow or adipose tissue. The proliferation, senescence and differentiation of TMSCs were assessed after the inhibition of STC1 expression. STC1 inhibition resulted in a significant decrease in the proliferation of TMSCs and did not affect the differentiation potential. To reveal the anti-oxidative ability of STC1 in TMSCs themselves or against other cell types, the generation of mitochondrial reactive oxygen species (ROS) in TMSC or ROS-mediated production of interleukin (IL)-1β from macrophage-like cells were detected. Interestingly, the basal level of ROS generation in TMSCs was significantly elevated after STC1 inhibition. Moreover, down-regulation of STC1 impaired the inhibitory effect of TMSCs on IL-1β production in macrophages. Taken together, these findings indicate that STC1 is highly expressed in TMSCs and plays a critical role in proliferating and ROS-regulatory abilities.

Conditioned Medium from Human Tonsil-Derived Mesenchymal Stem Cells Enhances Bone Marrow Engraftment via Endothelial Cell Restoration by Pleiotrophin

Cotransplantation of mesenchymal stem cells (MSCs) with hematopoietic stem cells (HSCs) has been widely reported to promote HSC engraftment and enhance marrow stromal regeneration. The present study aimed to define whether MSC conditioned medium could recapitulate the effects of MSC cotransplantation. Mouse bone marrow (BM) was partially ablated by the administration of a busulfan and cyclophosphamide (Bu–Cy)-conditioning regimen in BALB/c recipient mice. BM cells (BMCs) isolated from C57BL/6 mice were transplanted via tail vein with or without tonsil-derived MSC conditioned medium (T-MSC CM). Histological analysis of femurs showed increased BM cellularity when T-MSC CM or recombinant human pleiotrophin (rhPTN), a cytokine readily secreted from T-MSCs with a function in hematopoiesis, was injected with BMCs. Microstructural impairment in mesenteric and BM arteriole endothelial cells (ECs) were observed after treatment with Bu–Cy-conditioning regimen; however, T-MSC CM or rhPTN treatment restored the defects. These effects by T-MSC CM were disrupted in the presence of an anti-PTN antibody, indicating that PTN is a key mediator of EC restoration and enhanced BM engraftment. In conclusion, T-MSC CM administration enhances BM engraftment, in part by restoring vasculature via PTN production. These findings highlight the potential therapeutic relevance of T-MSC CM for increasing HSC transplantation efficacy.

Tensin-3 Regulates Integrin-Mediated Proliferation and Differentiation of Tonsil-Derived Mesenchymal Stem Cells

Human palatine tonsils are potential tissue source of multipotent mesenchymal stem cells (MSCs). The proliferation rate of palatine tonsil-derived MSCs (TMSCs) is far higher than that of bone marrow-derived MSCs (BMSCs) or adipose tissue-derived MSCs (ADSCs). In our previous study, we had found through DNA microarray analysis that tensin-3 (TNS3), a type of focal adhesion protein, was more highly expressed in TMSCs than in both BMSCs and ADSCs. Here, the role of TNS3 in TMSCs and its relationship with integrin were investigated. TNS3 expression was significantly elevated in TMSCs than in other cell types. Cell growth curves revealed a significant decrease in the proliferation and migration of TMSCs treated with siRNA for TNS3 (siTNS3). siTNS3 treatment upregulated p16 and p21 levels and downregulated SOX2 expression and focal adhesion kinase, protein kinase B, and c-Jun N-terminal kinase phosphorylation. siTNS3 transfection significantly reduced adipogenic differentiation of TMSCs and slightly decreased osteogenic and chondrogenic differentiation. Furthermore, TNS3 inhibition reduced active integrin beta-1 (ITGβ1) expression, while total ITGβ1 expression was not affected. Inhibition of ITGβ1 expression in TMSCs by siRNA showed similar results observed in TNS3 inhibition. Thus, TNS3 may play an important role in TMSC proliferation and differentiation by regulating active ITGβ1 expression.

Wound Healing Promoting Activity of Tonsil-Derived Stem Cells on 5-Fluorouracil-Induced Oral Mucositis Model

BACKGROUND

We first determined the efficacy of lesional injection of tonsil-derived MSCs (mesenchymal stem cells) for the treatment of 5-fluorouracil induced oral mucositis.

METHODS

Oral mucositis was induced in hamsters by administration of 5-fluorouracil (day 0, 2, 4) followed by mechanical trauma (day 1, 2, 4). The experimental groups included MT (mechanical trauma only), 5-FU + MT (mechanical trauma with 5-fluorouracil administration), TMSC (mechanical trauma with 5-fluorouracil administration, tonsil-derived mesenchymal stem cells injection), DEXA (mechanical trauma with 5-fluorouracil administration, dexamethasone injection), and saline (mechanical trauma with 5-fluorouracil administration, saline injection).

RESULTS

On day 10, gross and histologic analyses showed that nearly complete healing and epithelialization of the cheek mucosa of the TMSC group, whereas the other groups showed definite ulcerative lesions. Compared with the MT and DEXA groups, CD31 expression was greater in the TMSC group on days 10 and 14. Tendency towards a decrease in MMP2 expression with the time in the TMSC group was observed. In addition, the TMSC group showed higher expression of TGF-β, and NOX4 on day 10 compared with the other groups. Scratch assay demonstrated that the conditioned media harvested from tonsil-derived MSCs significantly increased migratory efficacy of NIH3T3 cells. Transwell assay showed that the preferential migration of tonsil-derived MSCs to the wound area.

CONCLUSION

Intralesional administration of tonsil-derived MSCs may accelerate wound healing of 5-fluorouracil induced oral mucositis by upregulating neovascularization and effective wound contraction. In addition, tonsil-derived MSCs might contribute to oral ulcer regeneration via the stimulation of fibroblast proliferation and migration.

The efficacy of conditioned medium released by tonsil-derived mesenchymal stem cells in a chronic murine colitis model

Tonsil-derived mesenchymal stem cells (TMSC) have characteristics of MSC and have many advantages. In our previous studies, intraperitoneal (IP) injection of TMSC in acute and chronic colitis mouse models improved the disease activity index, colon length, and the expression levels of proinflammatory cytokines. However, TMSC were not observed to migrate to the inflammation site in the intestine. The aim of this study was to verify the therapeutic effect of conditioned medium (CM) released by TMSC (TMSC-CM) in a mouse model of dextran sulfate sodium (DSS)-induced chronic colitis. TMSC-CM was used after seeding 5×105 cells onto a 100 mm dish and culturing for 5-7 days. TMSC-CM was concentrated (TMSC-CM-conc) by three times using a 100 kDa cut-off centrifugal filter. Seven-week-old C57BL/6 mice were randomly assigned to the following 5 groups: 1) normal, 2) colitis, 3) TMSC, 4) TMSC-CM, and 5) TMSC-CM-conc. Chronic colitis was induced by continuous oral administration of 1.5% dextran sulfate sodium (DSS) for 5 days, followed by 5 additional days of tap water feeding. This cycle was repeated two more times (total 30 days). Phosphate buffered saline (in the colitis group), TMSC, TMSC-CM, and TMSC-CM-conc were injected via IP route 4, 4, 12, and 4 times, respectively. Reduction of disease activity index, weight gain, recovery of colon length, and decreased in the expression level of the proinflammatory cytokines, interleukin (IL)-1β, IL-6, and IL-17 were observed at day 30 in the treatment groups, compared to control. However, histological colitis scoring and the expression level of tumor necrosis factor α and IL-10 did not differ significantly between each group. TMSC-CM showed an equivalent effect to TMSC related to the improvement of inflammation in the chronic colitis mouse model. The data obtained support the use of TMSC-CM to treat inflammatory bowel disease without any cell transplantation.

Optimization of Microenvironments Inducing Differentiation of Tonsil-Derived Mesenchymal Stem Cells into Endothelial Cell-Like Cells

Background

Stem cell engineering is appealing consideration for regenerating damaged endothelial cells (ECs) because stem cells can differentiate into EC-like cells. In this study, we demonstrate that tonsil-derived mesenchymal stem cells (TMSCs) can differentiate into EC-like cells under optimal physiochemical microenvironments.

Methods

TMSCs were preconditioned with Dulbecco's Modified Eagle Medium (DMEM) or EC growth medium (EGM) for 4 days and then replating them on Matrigel to observe the formation of a capillary-like network under light microscope. Microarray, quantitative real time polymerase chain reaction, Western blotting and immunofluorescence analyses were used to evaluate the expression of gene and protein of EC-related markers.

Results

Preconditioning TMSCs in EGM for 4 days and then replating them on Matrigel induced the formation of a capillary-like network in 3 h, but TMSCs preconditioned with DMEM did not form such a network. Genome analyses confirmed that EGM preconditioning significantly affected the expression of genes related to angiogenesis, blood vessel morphogenesis and development, and vascular development. Western blot analyses revealed that EGM preconditioning with gelatin coating induced the expression of endothelial nitric oxide synthase (eNOS), a mature EC-specific marker, as well as phosphorylated Akt at serine 473, a signaling molecule related to eNOS activation. Gelatin-coating during EGM preconditioning further enhanced the stability of the capillary-like network, and also resulted in the network more closely resembled to those observed in human umbilical vein endothelial cells.

Conclusion

This study suggests that under specific conditions, i.e., EGM preconditioning with gelatin coating for 4 days followed by Matrigel, TMSCs could be a source of generating endothelial cells for treating vascular dysfunction.

Identification of WNT16 as a Predictable Biomarker for Accelerated Osteogenic Differentiation of Tonsil-Derived Mesenchymal Stem Cells In Vitro

The application of mesenchymal stem cells (MSCs) for treating bone-related diseases shows promising outcomes in preclinical studies. However, cells that are isolated and defined as MSCs comprise a heterogeneous population of progenitors. This heterogeneity can produce variations in the performance of MSCs, especially in applications that require differentiation potential in vivo, such as the treatment of osteoporosis. Here, we aimed to identify genetic markers in tonsil-derived MSCs (T-MSCs) that can predict osteogenic potential. Using a single-cell cloning method, we isolated and established several lines of nondifferentiating (ND) or osteoblast-prone (OP) clones. Next, we performed transcriptome sequencing of three ND and three OP clones that maintained the characteristics of MSCs and determined the top six genes that were upregulated in OP clones. Upregulation of WNT16 and DCLK1 expression was confirmed by real-time quantitative PCR, but only WNT16 expression was correlated with the osteogenic differentiation of T-MSCs from 10 different donors. Collectively, our findings suggest that WNT16 is a putative genetic marker that predicts the osteogenic potential of T-MSCs. Thus, examination of WNT16 expression as a selection criterion prior to the clinical application of MSCs may enhance the therapeutic efficacy of stem cell therapy for bone-related complications, including osteoporosis.

Tonsil-derived stem cells as a new source of adult stem cells

Located near the oropharynx, the tonsils are the primary mucosal immune organ. Tonsil tissue is a promising alternative source for the high-yield isolation of adult stem cells, and recent studies have reported the identification and isolation of tonsil-derived stem cells (T-SCs) from waste surgical tissue following tonsillectomies in relatively young donors (i.e., under 10 years old). As such, T-SCs offer several advantages, including superior proliferation and a shorter doubling time compared to bone marrow-derived mesenchymal stem cells (MSCs). T-SCs also exhibit multi-lineage differentiation, including mesodermal, endodermal (e.g., hepatocytes and parathyroid-like cells), and even ectodermal cells (e.g., Schwann cells). To this end, numbers of researchers have evaluated the practical use of T-SCs as an alternative source of autologous or allogenic MSCs. In this review, we summarize the details of T-SC isolation and identification and provide an overview of their application in cell therapy and regenerative medicine.