Human Umbilical Cord MSCs as New Cell Sources for Promoting Periodontal Regeneration in Inflammatory Periodontal Defect

Piezoelectric hydrogel for treatment of periodontitis through bioenergetic activation

The impaired differentiation ability of resident cells and disordered immune microenvironment in periodontitis pose a huge challenge for bone regeneration. Herein, we construct a piezoelectric hydrogel to rescue the impaired osteogenic capability and rebuild the regenerative immune microenvironment through bioenergetic activation. Under local mechanical stress, the piezoelectric hydrogel generated piezopotential that initiates osteogenic differentiation of inflammatory periodontal ligament stem cells (PDLSCs) via modulating energy metabolism and promoting adenosine triphosphate (ATP) synthesis. Moreover, it also reshapes an anti-inflammatory and pro-regenerative niche through switching M1 macrophages to the M2 phenotype. The synergy of tilapia gelatin and piezoelectric stimulation enhances in situ regeneration in periodontal inflammatory defects of rats. These findings pave a new pathway for treating periodontitis and other immune-related bone defects through piezoelectric stimulation-enabled energy metabolism modulation and immunomodulation.

METTL3 promotes osteogenic differentiation of human umbilical cord mesenchymal stem cells by up-regulating m6A modification of circCTTN

BACKGROUND

Human umbilical cord mesenchymal stem cells (hUCMSCs) are promising seed cells in bone tissue engineering. circRNA and N6-methyladenosine (m6A) RNA methylation play important roles in osteogenic differentiation. Here, we investigated the potential relevance of a critical circRNA, hsa_circ_0003376 (circCTTN), and methyltransferase-like 3 (METTL3) in osteogenic differentiation of hUCMSCs.

METHODS

Expression of circCTTN after hUCMSC osteogenic induction was detected by qRT-PCR. Three databases (RMBase v2.0, BERMP, and SRAMP) were used to predict m6A sites of circCTTN. RNA was enriched by methylated RNA immunoprecipitation (MeRIP), followed by quantitative real-time polymerase chain reaction to detect m6A level of circCTTN after METTL3 overexpression and osteogenic induction. RNA pull-down, Western blotting, and protein mass spectrometry were performed to investigate the potential mechanisms by which METTL3 promoted m6A modification of circCTTN. Bioinformatic analyses based on database (STRING) search and co-immunoprecipitation were used to analyze the proteins that interacted with METTL3.

RESULTS

Overexpression of METTL3 promoted osteogenic differentiation of hUCMSCs and increased m6A level of circCTTN. Two potential m6A modification sites of circCTTN were predicted. No direct interaction between METTL3 and circCTTN was observed. Thirty-one proteins were pulled down by probes specific for circCTTN, including NOP2, and two m6A reading proteins, EIF3A and SND1. Bioinformatics analysis and co-immunoprecipitation showed that METTL3 interacted with EIF3A indirectly through NOP2.

CONCLUSIONS

METTL3 promotes the osteogenic differentiation of hUCMSCs by increasing the m6A level of circCTTN. However, METTL3 does not bind directly to circCTTN. METTL3 interacts with circCTTN indirectly through NOP2 and EIF3A.

Small Extracellular Vesicles Laden Oxygen-Releasing Thermosensitive Hydrogel for Enhanced Antibacterial Therapy against Anaerobe-Induced Periodontitis Alveolar Bone Defect

Periodontitis is a bacterially induced chronic destructive inflammatory disease that leads to irreversible destruction of the tooth supporting structure, including connective tissue destruction, bone resorption, and even tooth loss. Until now, there has been no effective treatment to repair inflammatory bone loss in periodontitis. Recently, small extracellular vesicles (sEVs) emerged as the essential paracrine factors of mesenchymal stem cells (MSCs) that mediated tissue regeneration. However, limitations of antimicrobial activity associated with the use of sEVs have led to the urgency of new alternative strategies. Currently, we investigated the potential of a biocompatible oxygen-releasing thermosensitive hydrogel laded with sEVs secreted by bone marrow MSCs (BMMSCs) for the alveolar bone defect in periodontitis. The hydrogel composed of different polymers such as chitosan (CS), poloxamer 407 (P407), and cross-linked hyaluronic acid (c-HA) conglomerating is a kind of nanoporous structure material. Then, the gel matrix further encapsulated sEVs and calcium peroxide nanoparticles to realize the control of sEVs and oxygen release. Furthermore, ascorbic acid was added to achieve the REDOX equilibrium and acid-base equilibrium. The experiments in vivo and in vitro proved its good biocompatibility and effectively inhibited the growth of the periodontal main anaerobe, relieved periodontal pocket anaerobic infections, and promoted the periodontal defect regeneration. Therefore, this finding demonstrated that it was a promising approach for combating anaerobic pathogens with enhanced and selective properties in periodontal diseases, even in other bacteria-induced infections, for future clinical application.

A multifunctional quercetin/polycaprolactone electrospun fibrous membrane for periodontal bone regeneration

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Comparison of Periodontal Ligament Stem Cells with Mesenchymal Stem Cells from Other Sources: A Scoping Systematic Review of In vitro and In vivo Studies

OBJECTIVE

The application of stem cells in regenerative medicine depends on their biological properties. This scoping review aimed to compare the features of periodontal ligament stem cells (PDLSSCs) with stem cells derived from other sources.

DESIGN

An electronic search in PubMed/Medline, Embase, Scopus, Google Scholar and Science Direct was conducted to identify in vitro and in vivo studies limited to English language.

RESULTS

Overall, 65 articles were included. Most comparisons were made between bone marrow stem cells (BMSCs) and PDLSCs. BMSCs were found to have lower proliferation and higher osteogenesis potential in vitro and in vivo than PDLSCs; on the contrary, dental follicle stem cells and umbilical cord mesenchymal stem cells (UCMSCs) had a higher proliferative ability and lower osteogenesis than PDLSCs. Moreover, UCMSCs exhibited a higher apoptotic rate, hTERT expression, and relative telomerase length. The immunomodulatory function of adipose-derived stem cells and BMSCs was comparable to PDLSCs. Gingival mesenchymal stem cells showed less sensitivity to long-term culture. Both pure and mixed gingival cells had lower osteogenic ability compared to PDLSCs. Comparison of dental pulp stem cells (DPSCs) with PDLSCs regarding proliferation rate, osteo/adipogenesis, and immunomodulatory properties was contradictory; however, in vivo bone formation of DPSCs seemed to be lower than PDLSCs.

CONCLUSION

In light of the performed comparative studies, PDLSCs showed comparable results to stem cells derived from other sources; however, further in vivo studies are needed to determine the actual pros and cons of stem cells in comparison to each other.

Attachment and proliferation of human gingival fibroblasts seeded on barrier membranes using Wharton's jelly-derived stem cells conditioned medium: An in vitro study

The effect of Wharton's jelly mesenchymal stem cells conditioned medium (WJMSCs-CM) and zinc oxide nanoparticles (ZnO-NPs) on cultured human gingival fibroblasts on various barrier membranes was investigated in this study. In this study, human gingival fibroblasts were prepared and cultured on three membranes: collagen membrane, acellular dermal matrix (ADM) with ZnO-NPs, and ADM without ZnO-NPs. WJMSCs-CM was given to the testing groups, while control groups received the same membranes without WJMSCs-CM. Following 48 and 72 h, 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tests were performed to assess cell survival. Cell proliferation on the membranes was also evaluated using 4',6-diamidino-2-phenylindole (DAPI) staining after 48 and 72 h. Field emission scanning electron microscopy was used to determine membrane surface structure and cell adhesion. Nanoparticles were also subjected to an energy-dispersive x-ray analysis to identify their chemical structure. Two-way analysis of variance was used to conduct the statistical analysis. The p-value ≤.05 was considered significant. When ADM-ZnO-NPs were combined with CM, fibroblast viability, and adhesion significantly differed from ADM-ZnO-NPs alone. DAPI results confirmed cell proliferation in all six groups on both experiment days. The abundance and concentrated distribution of cells during cell proliferation were found in CM-containing membranes, specifically the ADM-ZnO-NPs membrane, demonstrating the improved biocompatibility of the ADM-ZnO-NPs membrane for cell proliferation. The other groups did not significantly differ from one another. WJMSCs-CM positively affected the viability and proliferation of gingival fibroblasts, but only marginally. Under certain conditions, ZnO-NPs below a specific concentration increased the biocompatibility of the membranes.

Let-7a promotes periodontal bone regeneration of bone marrow mesenchymal stem cell aggregates via the Fas/FasL-autophagy pathway

Periodontal bone regeneration using bone marrow mesenchymal stem cell (BMMSC) transplantation is a promising method; however, the method for osteogenic differentiation of BMMSCs needs to be improved. In this research, we sought to identify the roles of let-7a in the osteogenesis of BMMSCs and to provide a potential method for periodontal bone regeneration. Our previous study revealed that Fas/FasL is a target of let-7a. In this study, we demonstrated that let-7a overexpression significantly enhanced BMMSC-CAs osteogenesis both in vitro and in vivo. Mechanistically, upregulation of Fas/FasL using the rfas/rfaslg plasmid obstructed the osteogenesis of BMMSCs by inhibiting autophagy. Furthermore, we confirmed that overexpression of let-7a activated autophagy and alleviated the inhibited osteogenesis by the autophagy inhibitor 3-MA and the rfas/rfaslg plasmid of BMMSCs. In general, our findings showed that let-7a promoted the osteogenesis of BMMSCs through the Fas/FasL-autophagy pathway, suggesting that the application of let-7a in BMMSC-CAs based periodontal bone regeneration could be a promising strategy.

Animal models for testing biomaterials in periodontal regeneration

Periodontitis is a prevalent oral disease. It can cause tooth loss and has a significant impact on patients' quality of life. While existing treatments can only slow the progression of periodontitis, they are unable to achieve complete regeneration and functional reconstruction of periodontal tissues. As a result, regenerative therapies based on biomaterials have become a focal point of research in the field of periodontology. Despite numerous studies reporting the superiority of new materials in periodontal regeneration, limited progress has been made in translating these findings into clinical practice. This may be due to the lack of appropriate animal models to simulate the tissue defects caused by human periodontitis. This review aims to provide an overview of established animal models for periodontal regeneration, examine their advantages and limitations, and outline the steps for model construction. The objective is to determine the most relevant animal models for periodontal regeneration based on the hypothesis and expected outcomes.

Stem cells and extracellular vesicles to improve preclinical orofacial soft tissue healing

Orofacial soft tissue wounds caused by surgery for congenital defects, trauma, or disease frequently occur leading to complications affecting patients' quality of life. Scarring and fibrosis prevent proper skin, mucosa and muscle regeneration during wound repair. This may hamper maxillofacial growth and speech development. To promote the regeneration of injured orofacial soft tissue and attenuate scarring and fibrosis, intraoral and extraoral stem cells have been studied for their properties of facilitating maintenance and repair processes. In addition, the administration of stem cell-derived extracellular vesicles (EVs) may prevent fibrosis and promote the regeneration of orofacial soft tissues. Applying stem cells and EVs to treat orofacial defects forms a challenging but promising strategy to optimize treatment. This review provides an overview of the putative pitfalls, promises and the future of stem cells and EV therapy, focused on orofacial soft tissue regeneration.

Mesenchymal condensation in tooth development and regeneration: a focus on translational aspects of organogenesis

The teeth are vertebrate-specific, highly specialized organs performing fundamental functions of mastication and speech, the maintenance of which is crucial for orofacial homeostasis and is further linked to systemic health and human psychosocial well-being. However, with limited ability for self-repair, the teeth can often be impaired by traumatic, inflammatory, and progressive insults, leading to high prevalence of tooth loss and defects worldwide. Regenerative medicine holds the promise to achieve physiological restoration of lost or damaged organs, and in particular an evolving framework of developmental engineering has pioneered functional tooth regeneration by harnessing the odontogenic program. As a key event of tooth morphogenesis, mesenchymal condensation dictates dental tissue formation and patterning through cellular self-organization and signaling interaction with the epithelium, which provides a representative to decipher organogenetic mechanisms and can be leveraged for regenerative purposes. In this review, we summarize how mesenchymal condensation spatiotemporally assembles from dental stem cells (DSCs) and sequentially mediates tooth development. We highlight condensation-mimetic engineering efforts and mechanisms based on ex vivo aggregation of DSCs, which have achieved functionally robust and physiologically relevant tooth regeneration after implantation in animals and in humans. The discussion of this aspect will add to the knowledge of development-inspired tissue engineering strategies and will offer benefits to propel clinical organ regeneration.

PRMT5 inhibition ameliorates inflammation and promotes the osteogenic differentiation of LPS‑induced periodontal stem cells via STAT3/NF‑κB signaling

It has been reported that protein arginine methyltransferase 5 (PRMT5) serves a significant role in osteogenic differentiation and inflammatory response. Nevertheless, its role in periodontitis as well as its underlying mechanism remain to be elucidated. The aim of the present study was to explore the role of PRMT5 in periodontitis and whether PRMT5 could reduce liposaccharide (LPS)-induced inflammation of human periodontal ligament stem cells (hPDLSCs) and promote osteogenic differentiation through STAT3/NF-κB signaling. In the current study, the expression levels of PRMT5 were determined in LPS-induced hPDLSCs by reverse transcription-quantitative PCR and western blot analysis. ELISA and western blot analysis were employed to assess the secretion and expression levels of inflammatory factors, respectively. The osteogenic differentiation and mineralization potential of hPDLSCs were evaluated using alkaline phosphatase (ALP) activity assay, Alizarin red staining and western blot analysis. Additionally, western blot analysis was applied to determine the expression levels of the STAT3/NF-κB signaling pathway-related proteins. The results showed that the expression levels of PRMT5 were significantly enhanced in LPS-induced hPDLSCs. Additionally, PRMT5 knockdown reduced the contents of IL-1β, IL-6, TNF-α, inducible nitric oxide synthase and cyclooxygenase-2. PRMT5 depletion also enhanced ALP activity, improved the mineralization ability and upregulated bone morphogenetic protein 2, osteocalcin and runt-related transcription factor 2 in LPS-induced hPDLSCs. Furthermore, PRMT5 knockdown inhibited inflammation and promoted the osteogenic differentiation of hPDLSCs via blocking the activation of the STAT3/NF-κB signaling pathway. In conclusion, PRMT5 inhibition suppressed LPS-induced inflammation and accelerated osteogenic differentiation in hPDLSCs via regulating STAT3/NF-κB signaling, thus providing a potential targeted therapy for the improvement of periodontitis.

Research Advances on Stem Cell-Derived Extracellular Vesicles Promoting the Reconstruction of Alveolar Bone through RANKL/RANK/OPG Pathway

Periodontal bone tissue defects and bone shortages are the most familiar and troublesome clinical problems in the oral cavity. Stem cell-derived extracellular vesicles (SC-EVs) have biological properties similar to their sources, and they could be a promising acellular therapy to assist with periodontal osteogenesis. In the course of alveolar bone remodeling, the RANKL/RANK/OPG signaling pathway is an important pathway involved in bone metabolism. This article summarizes the experimental studies of SC-EVs applied for the therapy of periodontal osteogenesis recently and explores the role of the RANKL/RANK/OPG pathway in their mechanism of action. Their unique patterns will open a new field of vision for people, and they will help to advance a possible future clinical treatment.

Engineered cell-overexpression of circular RNA hybrid hydrogels promotes healing of calvarial defects

Craniomaxillofacial bone defects seriously affect the physical and mental health of patients. Bone marrow mesenchymal stem cells (BMSCs) are "gold standard" cells used for bone repair. However, the collection of BMSCs is invasive, and the osteogenic capacity is limited with age. Human umbilical cord mesenchymal stem cells (hUCMSCs) are promising alternative seed cells for bone tissue engineering. Our group previously used high-throughput sequencing technology and bioinformatics methods to detect circ-CTTN (hsa-circ_0003376) molecules, which may play an essential role in the osteogenic differentiation of hUCMSCs. In this study, osteogenic induction in vitro showed that the overexpressing circ-CTTN (OE group) exhibits a more pronounced osteogenic phenotype. The levels of osteogenesis-related genes in the OE group were highly expressed. The gelatin-methacrylate (GelMA) hydrogel possessed excellent biocompatibility and was used to load hUCMSCs. In the rat calvarial defect, the OE group presented a larger bone healing volume and denser bone trabecular distribution than other groups. So far, the overexpression of circ-CTTN could enhance the osteogenic differentiation of hUCMSCs and accelerate bone reconstruction. Our research could provide a new strategy and a strong theoretical basis for promoting hUCMSC clinical application in bone tissue engineering.

Extracellular Vesicles Derived from Human Umbilical Cord Mesenchymal Stem Cells Attenuate Mast Cell Activation

The therapeutic potential of extracellular vesicles isolated from stem cells have been reported in several clinical diseases. Preclinical studies have demonstrated the beneficial effects of extracellular vesicles in the treatment of heart, kidney, liver, brain, and skin injuries. To address the putative therapeutic effects and mechanisms of extracellular vesicles derived from human umbilical cord mesenchymal stem cells on allergic activation in mast cells, we isolated extracellular vesicles from human umbilical cord-derived mesenchymal stem cells (UCMSCs) by tangential-flow filtration methods. The characteristics and identification of UCMSC-derived extracellular vesicles were examined via nanoparticle tracking analysis, transmission electron microscopy and protein marker analysis. Cytokines and tryptase in the cultured supernatant of KU812 cells were analyzed using an ELISA kit. Proteins in the MAPK and STAT5 signaling pathways were detected by Western blotting. This study showed that different doses of UCMSC-derived extracellular vesicles abolish IgE-stimulated KU812 cell activation and reduce the level of NF-κB, which subsequently leads to cell degranulation and the release of IL-1β, TNF-α and IL-6. Additionally, UCMSC-derived extracellular vesicles treatment blunted the IgE-induced signaling proteins p-P38, p-JNK and p-STAT5. Our results revealed a mechanism for anti-inflammation in which extracellular vesicles can affect the activation of mast cells and thus function in allergy regulation.

Comparison of therapeutic effects of mesenchymal stem cells from umbilical cord and bone marrow in the treatment of type 1 diabetes

Background

The therapeutic potential of mesenchymal stem cells (MSCs) in type 1 diabetes (T1D) has been demonstrated in both preclinical and clinical studies. MSCs that have been used in research on T1D are derived from various tissue sources, with bone marrow (BM) and umbilical cord (UC) tissues being the most commonly used. However, the influence of tissue origin on the functional properties and therapeutic effects of MSCs in T1D remains unclear. This study aimed to compare the therapeutic efficacy of UC-MSCs and BM-MSCs in a mouse model of T1D as well as in patients with T1D.

Methods

In non-obese diabetic (NOD) mice, the development of diabetes was accelerated by streptozotocin injections. Thereafter, diabetic mice were randomized and treated intravenously with UC-MSCs, BM-MSCs or phosphate-buffered saline as a control. Blood glucose and serum insulin were measured longitudinally after transplantation. At 14 days post-transplantation, pancreatic tissues were collected to assess insulitis and the β-cell mass. Flow cytometry was performed to evaluate the composition of T lymphocytes in the spleen and pancreatic lymph nodes of the NOD mice. In our retrospective study of patients with T1D, 28 recipients who received insulin therapy alone or a single transplantation of UC-MSCs or BM-MSCs were enrolled. The glycaemic control and β-cell function of the patients during the first year of follow-up were compared.

Results

In NOD mice, UC-MSC and BM-MSC transplantation showed similar effects on decreasing blood glucose levels and preserving β cells. The regulation of islet autoimmunity was examined, and no significant difference between UC-MSCs and BM-MSCs was observed in the attenuation of insulitis, the decrease in T helper 17 cells or the increase in regulatory T cells. In patients with T1D, MSC transplantation markedly lowered haemoglobin A1c (HbA1c) levels and reduced insulin doses compared to conventional insulin therapy. However, the therapeutic effects were comparable between UC-MSCs and BM-MSCs, and they also exerted similar effects on the endogenous β-cell function in the patients.

Conclusion

In conclusion, both UC-MSCs and BM-MSCs exhibited comparable therapeutic effects on improving glycaemic control and preserving β-cell function in T1D. Considering their abundance and higher cell yields, UC-MSCs appear to be more promising than BM-MSCs in clinical applications.

Trial registration NCT02763423. Registered on May 5, 2016—Retrospectively registered, https://www.clinicaltrials.gov/.

Activation of Functional Somatic Stem Cells Promotes Endogenous Tissue Regeneration

Periodontal ligament derived stem cells (PDLSCs) are capable of differentiating into multiple cell types and inducing a promising immunomodulation for tissue regeneration and disease treatment. However, it is still challenging to develop a practical approach to activate endogenous stem cells for tissue self-healing and regeneration. In this study, transcriptome analysis reveals that resveratrol promotes PDLSC stemness through activation of stem cell, osteoprogenitor, and chondroprogenitor markers. Self-renewal and multipotent differentiation abilities are also improved in resveratrol-treated PDLSCs. In addition, immunomodulation of PDLSCs is dramatically increased after resveratrol treatment. Mechanistically, we show that resveratrol activates ERK/WNT crosstalk through elevation of olfactory and growth factor signaling pathways to upregulate the expression levels of RUNX2 and FASL for osteogenesis and immunomodulation, respectively. By using a periodontitis animal model, administration of resveratrol partially rescues bone loss through activation of endogenous somatic stem cells and inhibition of inflammatory T-cell infiltration. Taken together, our findings identify a novel pharmacological approach to achieve autotherapies for endogenous tissue regeneration.

Cell-Derived Exosomes as Therapeutic Strategies and Exosome-Derived microRNAs as Biomarkers for Traumatic Brain Injury

Traumatic brain injury (TBI) is a complex, life-threatening condition that causes mortality and disability worldwide. No effective treatment has been clinically verified to date. Achieving effective drug delivery across the blood–brain barrier (BBB) presents a major challenge to therapeutic drug development for TBI. Furthermore, the field of TBI biomarkers is rapidly developing to cope with the many aspects of TBI pathology and enhance clinical management of TBI. Exosomes (Exos) are endogenous extracellular vesicles (EVs) containing various biological materials, including lipids, proteins, microRNAs, and other nucleic acids. Compelling evidence exists that Exos, such as stem cell-derived Exos and even neuron or glial cell-derived Exos, are promising TBI treatment strategies because they pass through the BBB and have the potential to deliver molecules to target lesions. Meanwhile, Exos have decreased safety risks from intravenous injection or orthotopic transplantation of viable cells, such as microvascular occlusion or imbalanced growth of transplanted cells. These unique characteristics also create Exos contents, especially Exos-derived microRNAs, as appealing biomarkers in TBI. In this review, we explore the potential impact of cell-derived Exos and exosome-derived microRNAs on the diagnosis, therapy, and prognosis prediction of TBI. The associated challenges and opportunities are also discussed.

Human Umbilical Cord Mesenchymal Stem Cells: Current Literature and Role in Periodontal Regeneration

Periodontal disease can cause irreversible damage to tooth-supporting tissues such as the root cementum, periodontal ligament, and alveolar bone, eventually leading to tooth loss. While standard periodontal treatments are usually helpful in reducing disease progression, they cannot repair or replace lost periodontal tissue. Periodontal regeneration has been demonstrated to be beneficial in treating intraosseous and furcation defects to varied degrees. Cell-based treatment for periodontal regeneration will become more efficient and predictable as tissue engineering and progenitor cell biology advance, surpassing the limitations of present therapeutic techniques. Stem cells are undifferentiated cells with the ability to self-renew and differentiate into several cell types when stimulated. Mesenchymal stem cells (MSCs) have been tested for periodontal regeneration in vitro and in humans, with promising results. Human umbilical cord mesenchymal stem cells (UC-MSCs) possess a great regenerative and therapeutic potential. Their added benefits comprise ease of collection, endless source of stem cells, less immunorejection, and affordability. Further, their collection does not include the concerns associated with human embryonic stem cells. The purpose of this review is to address the most recent findings about periodontal regenerative mechanisms, different stem cells accessible for periodontal regeneration, and UC-MSCs and their involvement in periodontal regeneration.

Epithelial Cell Rests of Malassez Provide a Favorable Microenvironment for Ameliorating the Impaired Osteogenic Potential of Human Periodontal Ligament Stem Cells

Human periodontal ligament stromal/stem cells (PDLSCs) are ideal candidates for periodontal regeneration and are of significant importance in clinical practice. However, PDLSCs derived from diseased microenvironments exert impaired behavior, which leads to the failure of periodontal regeneration. The epithelial cell rests of Malassez (ERM), which are involved in periodontal homeostasis, are residual cells from Hertwig's epithelial root sheath (HERS). However, the function of ERM remains largely unknown. Therefore, the aim of this study was to evaluate the effect of ERM on the osteogenic potential of PDLSCs from an impaired microenvironment. PDLSCs from healthy donors (H-PDLSCs), periodontitis donors (P-PDLSCs) and human ERM were harvested. Osteogenic evaluation showed a lower osteogenic potential of P-PDLSCs compared to that of H-PDLSCs. Then, we co-cultured ERM with P-PDLSCs, and the data showed that ERM promoted the expression of osteogenic genes and proteins in P-PDLSCs. In addition, we collected the PDLSCs from aged donors (A-PDLSCs) and analyzed the osteogenesis capacity of the A-PDLSCs and A-PDLSCs + ERM groups, which displayed similar results to P-PDLSCs. Finally, we evaluated the Wnt pathway, which is associated with osteogenic differentiation of stromal/stem cells, in A-PDLSCs + ERM and P-PDLSCs + ERM groups, which indicated that suppression of the Wnt pathway may result in an increase in the osteogenic properties of A-PDLSCs + ERM and P-PDLSCs + ERM groups. Taken together, the above findings shed new light on the function of ERM and provide a novel therapeutic for optimizing PDLSCs-based periodontal regeneration.

Transcriptomic profiling and functional prediction reveal aberrant expression of circular RNAs during osteogenic differentiation in human umbilical cord mesenchymal stromal cells

Circular RNAs (circRNAs) are crucial elements of non-coding RNA, that regulate various biological processes. To date, expression patterns and functional roles of circRNAs during osteogenic differentiation of human umbilical cord mesenchymal stromal cells (hUCMSCs) remain unknown. In this study, we analyzed RNA-sequence data to reveal expression profiles of circRNAs during osteogenesis of hUCMSCs, then elucidated the underlying mechanisms of action. We identified a total of 5457 circRNAs in hUCMSCs, of which 34 and 33 were upregulated and downregulated, respectively. We applied Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses to determine functions and related pathways of differentially expressed circRNAs. Moreover, we applied bioinformatics tools to construct competing endogenous RNA networks, comprising 10 circRNAs, 46 micro RNAs and 413 mRNAs. Furthermore, we predicted protein-coding potential of the upregulated circRNAs then constructed a co-expression network comprising the top 5 upregulated circRNAs and 75 RNA-binding proteins. Next, we validated 6 differentially-expressed circRNAs and found that overexpressing circ-CTTN could promote osteogenesis of hUCMSCs. Overall, our findings indicate that clusters of circRNAs are aberrantly expressed in hUCMSCs during osteogenic differentiation, hence lay a foundation for future research into promoting hUCMSCs osteogenic differentiation and bone regeneration.

CGF Membrane Promotes Periodontal Tissue Regeneration Mediated by hUCMSCs through Upregulating TAZ and Osteogenic Differentiation Genes

Concentrated growth factor (CGF) membranes are widely used in basic and clinical research of soft and hard tissue regeneration, but its effect on periodontal tissue regeneration is less studied. This study explored the role of CGF membranes in periodontal tissue regeneration mediated by human umbilical cord mesenchymal stem cells (hUCMSCs). HUCMSCs and human periodontal ligament fibroblasts (HPLFs) were extracted and identified by microscope and flow cytometry. The effects of the extracted CGF membrane on cell viability, osteogenic differentiation ability, osteopontin (OPN) expression, alkaline phosphatase (ALP) content, and osteogenic differentiation-related genes (Runt-related transcription factor 2 (RUNX2); osteocalcin (OCN); ALP), Tafazzin (TAZ) expression, and nuclear transfer were examined by MTT assay, alizarin red staining, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot. Rescue experiments were performed to examine the effects of TAZ transfection and cell coculture. In the identified hUCMSCs (positive expressions of CD29, CD44, CD146, and CD105), overexpressed TAZ (pc-TAZ) enhanced the promotive effect of CGF membrane on cell viability, cell cycle, mineralization, ALP content and expressions of OPN, TAZ and osteogenic differentiation-related genes, and nuclear transfer. However, silencing TAZ showed opposite effects. The coculture of hUCMSCs and HPLFs further promoted the basic biological functions of HPLFs by upregulating osteogenic differentiation-related genes and COL-1 but downregulated MMP1 expression. Pc-TAZ could enhance the effect of CGF membrane on promoting periodontal tissue regeneration. CGF membrane promoted periodontal tissue regeneration through upregulating TAZ and osteogenic differentiation-related genes.

Periodontal tissue regeneration combined with orthodontic treatment can improve clinical efficacy and periodontal function of patients with periodontitis

OBJECTIVE

To determine the efficacy of periodontal tissue regeneration (PTR) combined with orthodontic treatment in patients with periodontitis.

METHODS

A total of 118 patients with periodontitis admitted to our hospital between March 2017 and May 2019 were enrolled. Among them, 56 patients were treated with PTR as a regular group, while the rest 62 were treated with PTR combined with orthodontic treatment as a joint group. The two groups were compared in efficacy, total treatment time, recovery time for periodontal function, periodontal function-associated indexes before and after treatment, pain, serum inflammatory factors, adverse reactions, and treatment satisfaction.

RESULTS

The joint group showed significantly higher effective treatment rate (P<0.05), and experienced significantly shorter total treatment time and recovery time for periodontal function than the regular group (both P<0.05). Before treatment, there was no meaningful difference between the two groups in plaque index (PLI), periodontal pocket probing depth (PD), sulcus bleeding index (SBI), attachment loss (AL), visual analog scale (VAS) score, and serum IL-6, IL-1β and TNF-α levels, while after treatment, these indexes of both groups improved (all P<0.05), and the improvement in the joint group was more notable (P<0.05). Additionally, there were no significant difference between the two groups in the incidence of adverse reactions (P>0.05), and the joint group expressed significantly higher treatment satisfaction (P<0.05).

CONCLUSION

With a high safety, PTR combined with orthodontic treatment can effectively alleviate the clinical symptoms of patients and promote the recovery of their periodontal function, and is more acceptable, so it is worthy of clinical promotion.

Bioactive Materials for Soft Tissue Repair

Over the past decades, age-related pathologies have increased abreast the aging population worldwide. The increased age of the population indicates that new tools, such as biomaterials/scaffolds for damaged tissues, which display high efficiency, effectively and in a limited period of time, for the regeneration of the body's tissue are needed. Indeed, scaffolds can be used as templates for three-dimensional tissue growth in order to promote the tissue healing stimulating the body's own regenerative mechanisms. In tissue engineering, several types of biomaterials are employed, such as bioceramics including calcium phosphates, bioactive glasses, and glass-ceramics. These scaffolds seem to have a high potential as biomaterials in regenerative medicine. In addition, in conjunction with other materials, such as polymers, ceramic scaffolds may be used to manufacture composite scaffolds characterized by high biocompatibility, mechanical efficiency and load-bearing capabilities that render these biomaterials suitable for regenerative medicine applications. Usually, bioceramics have been used to repair hard tissues, such as bone and dental defects. More recently, in the field of soft tissue engineering, this form of scaffold has also shown promising applications. Indeed, soft tissues are continuously exposed to damages, such as burns or mechanical traumas, tumors and degenerative pathology, and, thereby, thousands of people need remedial interventions such as biomaterials-based therapies. It is known that scaffolds can affect the ability to bind, proliferate and differentiate cells similar to those of autologous tissues. Therefore, it is important to investigate the interaction between bioceramics and somatic/stem cells derived from soft tissues in order to promote tissue healing. Biomimetic scaffolds are frequently employed as drug-delivery system using several therapeutic molecules to increase their biological performance, leading to ultimate products with innovative functionalities. This review provides an overview of essential requirements for soft tissue engineering biomaterials. Data on recent progresses of porous bioceramics and composites for tissue repair are also presented.

Advancing application of mesenchymal stem cell-based bone tissue regeneration

Reconstruction of bone defects, especially the critical-sized defects, with mechanical integrity to the skeleton is important for a patient's rehabilitation, however, it still remains challenge. Utilizing biomaterials of human origin bone tissue for therapeutic purposes has provided a facilitated approach that closely mimics the critical aspects of natural bone tissue with regard to its properties. However, not only efficacious and safe but also cost-effective and convenient are important for regenerative biomaterials to achieve clinical translation and commercial success. Advances in our understanding of regenerative biomaterials and their roles in new bone formation potentially opened a new frontier in the fast-growing field of regenerative medicine. Taking inspiration from the role and multicomponent construction of native extracellular matrix (ECM) for cell accommodation, the ECM-mimicking biomaterials and the naturally decellularized ECM scaffolds were used to create new tissues for bone restoration. On the other hand, with the going deep in understanding of mesenchymal stem cells (MSCs), they have shown great promise to jumpstart and facilitate bone healing even in diseased microenvironments with pharmacology-based endogenous MSCs rescue/mobilization, systemic/local infusion of MSCs for cytotherapy, biomaterials-based approaches, cell-sheets/-aggregates technology and usage of subcellular vesicles of MSCs to achieve scaffolds-free or cell-free delivery system, all of them have been shown can improve MSCs-mediated regeneration in preclinical studies and several clinical trials. Here, following an overview discussed autogenous/allogenic and ECM-based bone biomaterials for reconstructive surgery and applications of MSCs-mediated bone healing and tissue engineering to further offer principles and effective strategies to optimize MSCs-based bone regeneration.

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Focusing on MSCs based bone regeneration.

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Discussed cytotherapy, cell-free therapies and cell-aggregates technology in detail.

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Stating the approaches of MSCs in diseased microenvironments.

Chitosan hydrogel incorporated with dental pulp stem cell-derived exosomes alleviates periodontitis in mice via a macrophage-dependent mechanism

Periodontitis is caused by host immune-inflammatory response to bacterial insult. A high proportion of pro-inflammatory macrophages to anti-inflammatory macrophages leads to the pathogenesis of periodontitis. As stem cell-derived exosomes can modulate macrophage phenotype, dental pulp stem cell-derived exosomes (DPSC-Exo) can effectively treat periodontitis. In this study, we demonstrated that DPSC-Exo-incorporated chitosan hydrogel (DPSC-Exo/CS) can accelerate the healing of alveolar bone and the periodontal epithelium in mice with periodontitis. Gene Ontology (GO) term enrichment analysis showed that treatment with DPSC-Exo/CS ameliorated periodontal lesion by suppressing periodontal inflammation and modulating the immune response. Specifically, DPSC-Exo/CS facilitated macrophages to convert from a pro-inflammatory phenotype to an anti-inflammatory phenotype in the periodontium of mice with periodontitis, the mechanism of which could be associated with miR-1246 in DPSC-Exo. These results not only shed light on the therapeutic mechanism of DPSC-Exo/CS but also provide the basis for developing an effective therapeutic approach for periodontitis.

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DPSC-Exo/CS accelerates the healing of periodontal tissues in mice with periodontitis.

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DPSC-Exo/CS ameliorates periodontitis by modulating the immune response.

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The immunomodulatory effects of DPSC-Exo/CS are associated with miR-1246 in DPSC-Exo.

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DPSC-Exo/CS is a promising therapy for periodontitis.

Soft Matrix Combined With BMPR Inhibition Regulates Neurogenic Differentiation of Human Umbilical Cord Mesenchymal Stem Cells

Stem cells constantly encounter as well as respond to a variety of signals in their microenvironment. Although the role of biochemical factors has always been emphasized, the significance of biophysical signals has not been studied until recently. Additionally, biophysical elements, like extracellular matrix (ECM) stiffness, can regulate functions of stem cells. In this study, we demonstrated that soft matrix with 1-10 kPa can induce neural differentiation of human umbilical cord mesenchymal stem cells (hUC-MSCs). Importantly, we used a combination of soft matrix and bone morphogenetic protein receptor (BMPR) inhibition to promote neurogenic differentiation of hUC-MSCs. Furthermore, BMPR/SMADs occurs in crosstalk with the integrinβ1 downstream signaling pathway. In addition, BMPR inhibition plays a positive role in maintaining the undifferentiated state of hUC-MSCs on the hydrogel substrate. The results provide further evidence for the molecular mechanisms via which stem cells convert mechanical inputs into fateful decisions.

Human amniotic mesenchymal stromal cells promote bone regeneration via activating endogenous regeneration

Rationale: The effectiveness of stem cell based-therapy for bone regeneration has been demonstrated; yet, clinical application of autologous stem cells is still limited by invasive acquisition, long culture processes, and high cost. Besides, it remains controversial whether autologous stem cells could directly participate in tissue repair after differentiation. Thus, increasing allogeneic stem cells have been developed into drugs to indirectly activate endogenous regeneration and induce tissue regeneration. Human amniotic mesenchymal stromal cells (HAMSCs) have been extensively studied, showing multiple regulatory functions, but mechanisms of HAMSCs in promoting bone regeneration are remain unclear. Methods: Proteome profile of HAMSCs and their functions on vascularized bone regeneration were investigated in vitro, while rabbit cranial defect model was used to further detect the effects of bone formation in vivo. Results: HAMSCs secrete many osteogenic, angiogenic, and immunomodulatory cytokines. In vitro, HAMSCs can promote human bone-marrow mesenchymal stromal cells (HBMSCs) migration and osteogenic differentiation; promote the capillary-tube formation of human umbilical vascular endothelial cells (HUVECs), induce HUVECs migration and pro-angiogenic genes expression, and promote M2 macrophage polarization. Further, in vivo studies suggested that transplanted HAMSCs could survive and induce M2 macrophages to secrete bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) in rabbits' skull defects at an early stage, and, in turn, promote more new bone formation. Conclusion: HAMSCs have good biocompatibility and paracrine function to promote bone repair by stimulating endogenous regeneration.

Integration of Human Umbilical Cord Mesenchymal Stem Cells-Derived Exosomes with Hydroxyapatite-Embedded Hyaluronic Acid-Alginate Hydrogel for Bone Regeneration

The treatment of bone defects has plagued clinicians. Exosomes, the naturally secreted nanovesicles by cells, exhibit great potential in bone defect regeneration to realize cell-free therapy. In this work, we successfully revealed that human umbilical cord mesenchymal stem cells-derived exosomes could effectively promote the proliferation, migration, and osteogenic differentiation of a murine calvariae preosteoblast cell line in vitro. Considering the long period of bone regeneration, to effectively exert the reparative effect of exosomes, we synthesized an injectable hydroxyapatite (HAP)-embedded in situ cross-linked hyaluronic acid-alginate (HA-ALG) hydrogel system to durably retain exosomes at the defect sites. Then, we combined the exosomes with the HAP-embedded in situ cross-linked HA-ALG hydrogel system to repair bone defects in rats in vivo. The results showed that the combination of exosomes and composite hydrogel could significantly enhance bone regeneration. Our experiment provides a new strategy for exosome-based therapy, which shows great potential in future tissue and organ repair.

Recombinant Klotho Protects Human Periodontal Ligament Stem Cells by Regulating Mitochondrial Function and the Antioxidant System during H2O2-Induced Oxidative Stress

Human periodontal ligament stem cells (hPDLSCs) are a favourable source for tissue engineering, but oxidative stress conditions during cell culture and transplantation could affect stem cell viability and stemness, leading to failed regeneration. The aim of this study was to evaluate the antioxidant and protective effects of Klotho, an antiageing protein, against cell damage and the loss of osteogenesis in hPDLSCs in H₂O₂-induced oxidative environments. H₂O₂ was used as an exogenous reactive oxygen species (ROS) to induce oxidative stress. Recombinant human Klotho protein was administered before H₂O₂ treatment. Multitechniques were used to assess antioxidant activity, cell damage, and osteogenic ability of hPDLSCs in oxidative stress and the effects of Klotho on hPDLSCs. Mitochondrial function was analyzed by an electron microscopy scan of cellular structure, mitochondrial DNA copy number, and cellular oxygen consumption rate (OCR). Furthermore, we explored the pathway by which Klotho may function to regulate the antioxidant system. We found that pretreatment with recombinant human Klotho protein could enhance SOD activity and reduce intracellular oxidative stress levels. Klotho reduced H₂O₂-induced cellular damage and eventually maintained the osteogenic differentiation potential of hPDLSCs. Notably, Klotho promoted mitochondrial function and activated antioxidants by negatively regulating the PI3K/AKT/FoxO1 pathway. The findings suggest that Klotho protein enhanced the antioxidative ability of hPDLSCs and protected stem cell viability and stemness from H₂O₂-induced oxidative stress by restoring mitochondrial functions and the antioxidant system.

Prostaglandin E2 Receptor 2 Modulates Macrophage Activity for Cardiac Repair

Background

Prostaglandin E₂ has long been known to be an immune modulator. It is released after tissue injury and plays a role in modulating macrophage activities, which are essential for tissue regeneration. However, the involvement of prostaglandin E₂ receptor 2 (EP2)–dependent regulation of macrophages in postischemic heart is unclear. This study aims to evaluate the role of EP2 in damaged heart.

Methods and Results

The effect of EP2 in postischemic heart was evaluated using EP2‐deficient transgenic mice. We demonstrated that cardiac function was worse after myocardial injury on loss of EP2. Furthermore, EP2 deficiency also altered proinflammatory response and resulted in a defect in macrophage recruitment to the injured myocardium. Transcriptome analysis revealed that the expression of erythroid differentiation regulator 1 (Erdr1) was significantly induced in EP2‐deficient macrophages. Knocking down Erdr1 expression restored migration ability of EP2‐deficient cells both in vitro and in vivo. By using a genetic fate‐mapping approach, we showed that abolishment of EP2 expression effectively attenuated cell replenishment.

Conclusions

The EP2‐dependent signaling pathway plays a critical role in regulating macrophage recruitment to the injured myocardium, thereby exerting a function in modulating the inflammatory microenvironment for cardiac repair.

FoxO1 Overexpression Ameliorates TNF-α-Induced Oxidative Damage and Promotes Osteogenesis of Human Periodontal Ligament Stem Cells via Antioxidant Defense Activation

Periodontitis is a chronic disease that includes the pathologic loss of periodontal tissue and alveolar bone. The inflammatory environment in periodontitis impairs the osteogenic differentiation potential and depresses the regeneration capacity of human periodontal ligament stem cells (hPDLSCs). Since Forkhead box protein O1 (FoxO1) plays an important role in redox balance and bone formation, we investigated the role of FoxO1 in oxidative stress resistance and osteogenic differentiation in an inflammatory environment by overexpressing FoxO1 in hPDLSCs. First, we found that FoxO1 overexpression reduced reactive oxygen species (ROS) accumulation, decreased malondialdehyde (MDA) levels, and elevated antioxidant potential under oxidative condition. Next, the overexpression of FoxO1 protected hPDLSCs against oxidative damage, which involved stabilization of the mitochondrial membrane potential. Third, overexpressed FoxO1 promoted extracellular matrix (ECM) mineralization and increased the expression of the osteogenic markers Runx2 and SP7 in the inflammatory environment. These results indicated that FoxO1 overexpression in hPDLSCs has an anti-inflammatory effect, increases antioxidative capacity, and positively regulates osteogenesis in a mimicked inflammatory environment.

Mesenchymal stem cell transplantation alleviates experimental Sjögren's syndrome through IFN-β/IL-27 signaling axis

Rationale: Although mesenchymal stem cell (MSC) transplantation has been proved to be an effective therapeutic approach to treat experimental Sjögren's syndrome (SS), the detailed underlying mechanisms remains unknown. IL-27 has diverse influences on the regulation of T cell differentiation and was involved in SS through modulating immune response. Here we aimed to explore whether IL-27-mediated regulation of immune cells was responsible for the beneficial effects of MSC transplantation on SS.

Methods: The SS-like symptoms were evaluated in IL-27 deficient and recombinant IL-27-treated NOD mice. The MSCs were infused into NOD mice via the tail vein. The histological features of submandibular glands, saliva flow rate and serum IL-27 were examined. The effects of MSCs on the IL-27 production and Th17/Treg cell in SS patients and mice in vitro and in vivo were determined for the mechanistic study.

Results: This study showed that SS patients had decreased IL-27 level and increased ratio of Th17/Treg cells. Consistently, exacerbated SS-like symptoms were observed in IL-27 deficient NOD mice, along with increased ratio of Th17/Treg cells. Importantly, MSC transplantation alleviated SS-like symptoms by elevating the level of IL-27 to restore Th17/Treg balance in NOD mice. Mechanistically, MSC-secreted interferon-β (IFN-β) promote dendritic cells to produce IL-27.

Conclusions: Thus, we have revealed a previously unrecognized function of MSC-mediated IL-27 production by DCs in suppressing SS-like syndrome, which provided evidences for clinical application of MSC in patients with SS.

Mesenchymal stem cell-derived exosomes as a nanotherapeutic agent for amelioration of inflammation-induced astrocyte alterations in mice

Mesenchymal stem cell-derived exosomes (MSC-Exo) have robust anti-inflammatory effects in the treatment of neurological diseases such as epilepsy, stroke, or traumatic brain injury. While astrocytes are thought to be mediators of these effects, their precise role remains poorly understood. To address this issue, we investigated the putative therapeutic effects and mechanism of MSC-Exo on inflammation-induced alterations in astrocytes.

Methods: Lipopolysaccharide (LPS)-stimulated hippocampal astrocytes in primary culture were treated with MSC-Exo, which were also administered in pilocarpine-induced status epilepticus (SE) mice. Exosomal integration, reactive astrogliosis, inflammatory responses, calcium signaling, and mitochondrial membrane potentials (MMP) were monitored. To experimentally probe the molecular mechanism of MSC-Exo actions on the inflammation-induced astrocytic activation, we inhibited the nuclear factor erythroid-derived 2, like 2 (Nrf2, a key mediator in neuroinflammation and oxidative stress) by sgRNA (in vitro) or ML385 (Nrf2 inhibitor) in vivo.

Results: MSC-Exo were incorporated into hippocampal astrocytes as well as attenuated reactive astrogliosis and inflammatory responses in vitro and in vivo. Also, MSC-Exo ameliorated LPS-induced aberrant calcium signaling and mitochondrial dysfunction in culture, and SE-induced learning and memory impairments in mice. Furthermore, the putative therapeutic effects of MSC-Exo on inflammation-induced astrocytic activation (e.g., reduced reactive astrogliosis, NF-κB deactivation) were weakened by Nrf2 inhibition.

Conclusions: Our results show that MSC-Exo ameliorate inflammation-induced astrocyte alterations and that the Nrf2-NF-κB signaling pathway is involved in regulating astrocyte activation in mice. These data suggest the promising potential of MSC-Exo as a nanotherapeutic agent for the treatment of neurological diseases with hippocampal astrocyte alterations.

Biomimetic open porous structured core-shell microtissue with enhanced mechanical properties for bottom-up bone tissue engineering

Background: Microtissues constructed with hydrogels promote cell expansion and specific differentiation by mimicking the microarchitecture of native tissues. However, the suboptimal mechanical property and osteogenic activity of microtissues fabricated by natural polymers need further improvement for bone reconstruction application. Core-shell designed structures are composed of an inner core part and an outer part shell, combining the characteristics of different materials, which improve the mechanical property of microtissues. Methods: A micro-stencil array chip was used to fabricate an open porous core-shell micro-scaffold consisting of gelatin as shell and demineralized bone matrix particles modified with bone morphogenetic protein-2 (BMP-2) as core. Single gelatin micro-scaffold was fabricated as a control. Rat bone marrow mesenchymal stem cells (BMSCs) were seeded on the micro-scaffolds, after which they were dynamic cultured and osteo-induced in mini-capsule bioreactors to fabricate microtissues. The physical characteristics, biocompatibility, osteo-inducing and controlled release ability of the core-shell microtissue were evaluated in vitro respectively. Then microtissues were tested in vivo via ectopic implantation and orthotopic bone implantation in rat model. Results: The Young's modulus of core-shell micro-scaffold was nearly triple that of gelatin micro-scaffold, which means the core-shell micro-scaffolds have better mechanical property. BMSCs rapidly proliferated and retained the highest viability on core-shell microtissues. The improved osteogenic potential of core-shell microtissues was evidenced by the increased calcification based on von kossa staining and osteo-relative gene expression. At 3months after transplantation, core-shell microtissue group formed the highest number of mineralized tissues in rat ectopic subcutaneous model, and displayed the largest amount of new bony tissue deposition in rat orthotopic cranial defect. Conclusion: The novel core-shell microtissue construction strategy developed may become a promising cell delivery platform for bone regeneration.

A collagen scaffold loaded with human umbilical cord-derived mesenchymal stem cells facilitates endometrial regeneration and restores fertility

In women of reproductive age, severe injuries to the endometrium are often accompanied by endometrial scar formation or intrauterine adhesions (IUAs), which can result in infertility or miscarriage. Although many approaches have been used to treat severe IUAs, high recurrence rates and endometrial thinning have limited therapeutic efficiency. In this study, a collagen scaffold (CS) loaded with human umbilical cord-derived mesenchymal stem cells (UC-MSCs) was fabricated and applied for endometrial regeneration. The CS/UC-MSCs promoted human endometrial stromal cell proliferation and inhibited apoptosis in vitro through paracrine effects. In a model of endometrial damage, transplantation with the CS/UC-MSCs maintained normal luminal structure, promoted endometrial regeneration and collagen remodeling, induced intrinsic endometrial cell proliferation and epithelium recovery, and enhanced the expression of estrogen receptor α and progesterone receptor. An improved ability of the regenerated endometrium to receive embryos was confirmed. Together, our results indicate that the CS/UC-MSCs promoted endometrial structural reconstruction and functional recovery. Topical administration of the CS/UC-MSCs after trans-cervical resection of adhesions might prevent re-adhesion, promote endometrium regeneration and improve pregnancy outcomes for patients with severe IUAs. STATEMENT OF SIGNIFICANCE: Intrauterine adhesions due to severe endometrium injuries happen frequently in clinic and become one of the crucial reasons for women's infertility or miscarriage. Therefore, how to regenerate the damaged endometrium is a big challenge. In this study, a collagen scaffold (CS) loaded with human umbilical cord-derived mesenchymal stem cells (UC-MSCs) was fabricated and applied for endometrium regeneration. Herein, UC-MSCs, known for low immunogenicity and high proliferative potential, exhibit promising potential for endometrium regeneration; and collagen scaffolds provide suitable physical support. It was proved that transplantation with CS/UC-MSCs promoted endometrial regeneration and fertility restoration. It suggested that topical administration of CS/UC-MSCs in uterus could be a promising strategy for patients suffering severe intrauterine adhesion and infertility.

Comparison of therapeutic effects of different mesenchymal stem cells on rheumatoid arthritis in mice

Background

Rheumatoid arthritis (RA) is a chronic and nonspecific autoimmune disease, which leads to joint destruction and deformity. To investigate the potential of human mesenchymal stem cells (MSCs) as a new therapeutic strategy for patients with RA, we compared the therapeutic effects of bone marrow derived MSCs (BMSCs), umbilical cord derived MSCs (UCs), and stem cells derived from human exfoliated deciduous teeth (SHED) on collagen-induced arthritis (CIA) in mice.

Methods

A total of 24 DBA/1 mice were infused with type II collagen to induce RA in the experimental model. MSC-treated mice were infused with UCs, BMSCs, and SHED, respectively. Bone erosion and joint destruction were measured by micro-computed tomographic (micro-CT) analysis and hematoxylin and eosin staining. The levels of tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) were measured by immunohistochemistry and Enzyme-Linked Immunosorbent Assay (ELISA).

Results

Systemic delivery of MSCs significantly improved the severity of the symptoms related to CIA to greater extent compared with the untreated control group. Micro-CT revealed reduced bone erosions in the metatarsophalangeal joints upon treatment with MSCs. Additionally, according to histologic evaluation, reduced synovitis and articular destruction were observed in MSC-treated groups. The levels of TNF-α and IL-1β in the serum and joints decreased with treatment by MSCs.

Conclusion

Our findings suggest that systemic infusion of UCs, BMSCs, and SHED may significantly alleviate the effects of RA. The therapeutic effect of BMSCs was greater than that of SHED, while the UCs were shown to have the best therapeutic effect on CIA mice. In conclusion, compared with BMSCs and SHED, UCs may be a more suitable source of MSCs for the treatment of patients with RA.

IGF-1C domain-modified hydrogel enhances therapeutic potential of mesenchymal stem cells for hindlimb ischemia

BACKGROUND

Poor cell engraftment and survival after transplantation limited the application of stem cell therapy. Synthetic biomaterials could provide an artificial microenvironment for stem cells, thereby improve cell survival and enhance the therapeutic efficiency of stem cells.

METHODS

We synthesized a hydrogel by conjugating C domain peptide of insulin-like growth factor-1 (IGF-1C) onto chitosan (CS-IGF-1C hydrogel). Human placenta-derived mesenchymal stem cells (hP-MSCs), which constitutively express a red fluorescent protein (RFP) and renilla luciferase (Rluc), were co-transplanted with CS-IGF-1C hydrogel into a murine hindlimb ischemia model. Transgenic mice expressing firefly luciferase (Fluc) under the promoter of vascular endothelial growth factor receptor 2 (VEGFR2-Luc) were used. Dual bioluminescence imaging (BLI) was applied for tracking the survival of hP-MSCs by Rluc imaging and the VEGFR2 signal pathway activation by Fluc imaging. To investigate the therapeutic mechanism of CS-IGF-1C hydrogel, angiographic, real-time PCR, and histological analysis were carried out.

RESULTS

CS-IGF-1C hydrogel could improve hP-MSCs survival as well as promote angiogenesis as confirmed by dual BLI. These results were consistent with accelerated skeletal muscle structural and functional recovery. Histology analysis confirmed that CS-IGF-1C hydrogel robustly prevented fibrosis as shown by reduced collagen deposition, along with increased angiogenesis. In addition, the protective effects of CS-IGF-1C hydrogel, such as inhibiting H2O2-induced apoptosis and reducing inflammatory responses, were proved by in vitro experiments.

CONCLUSIONS

Taken together, IGF-1Cs provides a conducive niche for hP-MSCs to exert pro-mitogenic, anti-apoptotic, and pro-angiogenic effects, as well as to inhibit fibrosis. Thus, the incorporation of functional peptide into bioscaffolds represents a safe and feasible approach to augment the therapeutic efficacy of stem cells.

Mesenchymal stem cell‑derived extracellular vesicles promote the in vitro proliferation and migration of breast cancer cells through the activation of the ERK pathway

Mesenchymal stem cells (MSCs) have been demonstrated to be involved in tumor progression and the modulation of the tumor microenvironment, partly through their secretome. Extracellular vesicles (EVs) are membranous nanovesicles secreted by multiple types of cells and have been demonstrated to mediate intercellular communication in both physiological and pathological conditions. However, numerous questions still remain regarding the underlying mechanisms and functional consequences of these interactions. The purpose of this study was to investigate the effects of human umbilical cord mesenchymal stem cell‑derived EVs (hUC‑MSC‑EVs) on the proliferation, migration and invasion of human breast cancer cells. We successfully generated and identified hUC‑MSCs and hUC‑MSC‑EVs which were used in this study. The results revealed that treatment of the MDA‑MB‑231 and MCF‑7 human breast cancer cells with medium containing hUC‑MSC‑EVs significantly enhanced the proliferation, migration and invasion of the cells in vitro. Treatment of the cells with medium containing hUC‑MSC‑EVs also reduced E‑cadherin expression and increased N‑cadherin expression, thus promoting the epithelial‑mesenchymal transition (EMT) of the breast cancer cells. Treatment of the breast cancer cells with extracellular signal‑regulated kinase (ERK) inhibitor prior to the interaction with hUC‑MSC‑EVs significantly reversed the enhanced proliferation, migration and invasion, as well as the EMT of the breast cancer cells induced by the hUC‑MSC‑EVs. On the whole, these data indicate that hUC‑MSC‑EVs promote the invasive and migratory potential of breast cancer cells through the induction of EMT via the ERK pathway, leading to malignant tumor progression and metastasis. Taken together, the findings of this study suggest that targeting pathways to reverse EMT may lead to the development of novel therapeutic approaches with which to combat breast cancer.

Bioengineered bladder patches constructed from multilayered adipose-derived stem cell sheets for bladder regeneration

Cell-seeded scaffolds are a common route of cell transplantation for bladder repair and reconstruction. However, when cell suspensions are harvested, proteolytic enzymes often cause extracellular matrix damage and loss of intercellular junctions. To overcome this problem, we developed a bioengineered three-dimensional bladder patch comprising porous scaffolds and multilayered adipose-derived stem cell (ASC) sheets, and evaluated its feasibility for bladder regeneration in a rat model. Adipose-derived stem cells (ASCs) were labeled with ultrasmall super-paramagnetic iron oxide (USPIO) nanoparticles. ASC patches were constructed using multilayered USPIO-labeled ASC sheets and porous polyglycolic acid scaffolds. To monitor the distribution and localization of bioengineered bladder patches in live animals, magnetic resonance imaging (MRI) was performed 2 weeks, 4 weeks and 8 weeks after transplantation. The bladder regenerative potential of ASC patches was further evaluated by urodynamic and histological analysis. Scanning electron microscopy indicated that cell sheets adhered tightly to the scaffold. MRI showed hypointense signals that lasted up to 8 weeks at the site of USPIO-labeled ASC sheet transplants. Immunofluorescence demonstrated that these tissue-engineered bladder patches promoted regeneration of urothelium, smooth muscle, neural cells and blood vessels. Urodynamic testing revealed that the ASC patch restored bladder function with augmented capacity. The USPIO-labeled ASC patch provides a promising perspective on image-guided tissue engineering and holds great promise as a safe and effective therapeutic strategy for bladder regeneration. STATEMENT OF SIGNIFICANCE: Adipose-derived stem cell (ASC) sheets avoid enzymatic dissociation and preserve the cell-to-cell interactions and extracellular matrix (ECM) proteins, which exhibit great potential for tissue regeneration. In this study, we developed a bioengineered three-dimensional bladder patch comprising porous scaffolds and multilayered ASC sheets, and evaluated its feasibility for bladder regeneration in a rat model. Tissue-engineered bladder patches restored bladder function and promoted regeneration of urothelium, smooth muscle, neural cells and blood vessels. Moreover, ultrasmall super-paramagnetic iron oxide (USPIO)-labeled bladder patches can be dynamically monitored in vivo by noninvasive MRI for long periods of time. Therefore, The USPIO-labeled bladder patch provides a promising image-guided therapeutic strategy for bladder regeneration.

Necrostatin-1 promotes ectopic periodontal tissue like structure regeneration in LPS-treated PDLSCs

Necroptosis is a programmed necrosis, regulated by receptor interacting protein kinase 1(RIP1) and receptor interacting protein kinase 3(RIP3), and could be inhibited by necrostatin-1(Nec-1) specifically. This study aims to evaluate the effect of Nec-1 on LPS-treated periodontal ligament stem cells (PDLSCs). In the research, three groups were established: normal cultured PDLSCs, Porphyromonas gingivalis (Pg)-LPS stimulated PDLSCs and Pg-LPS+Nec-1 treated PDLSCs. The expression of RIP1 and RIP3 and osteogenic differentiation of PDLSCs in three groups were analyzed. Then, we constructed cell aggregates (CA) using PDLSCs, then PDLSCs-CA were combined with Bio-Oss in three groups were transplanted subcutaneously in nude mice to assess their potentials of periodontal tissue regeneration. The results showed that RIP1 and RIP3 were fully expressed in Pg-LPS stimulated PDLSCs and the level increased significantly. Nec-1 inhibited RIP1-RIP3 interaction, and further inhibited necroptosis of PDLSCs in inflammatory state. Moreover, Nec-1 pretreatment ameliorates the osteogenic differentiation of LPS-treated PDLSCs and can effectively promote the cementum like structure ectopic regenerative ability of PDLSCs in nude mice. These findings show RIP1/RIP3-mediated necroptosis is an important mechanism of cell death in PDLSCs. Nec-1 has a protective effect in reducing cell death and promotes ectopic periodontal tissue like structure regeneration by inhibiting necroptosis. Nec-1 is a hopeful therapeutic agent which protects cells from necroptosis and ameliorates functional outcome.

Comparative evaluation of the osteogenic capacity of human mesenchymal stem cells from bone marrow and umbilical cord tissue

Mesenchymal stem cells (MSCs) have been extensively investigated in the field of regenerative medicine. Human bone MSCs (BMSCs) have become a common type of seed cell for bone tissue engineering. However, the viability and cell number of BMSCs are negatively correlated with donor age, and as the extraction process is painful, this method has not been widely used. As human umbilical cord MSCs (UCMSCs) may be harvested inexpensively and inexhaustibly, the present study evaluated and compared the regenerative potential of UCMSCs and BMSCs to determine whether UCMSCs may be used as a novel cell type for bone regeneration. In the present study, the proliferation and osteogenic capacity of BMSCs and UCMSCs was compared in vitro. BMSCs and UCMSCs were respectively combined with biofunctionalized macroporous calcium phosphate cement, and their bone regenerative potentials were determined by investigating their capacity for ectopic bone formation in a nude mouse model as well as their efficacy in a rat model of tibia bone defect. The extent of bone regeneration was examined by X-ray, histological and immunohistochemical analyses. The results revealed that UCMSCs exhibited a good osteogenic differentiation potential, similarly to that of BMSCs, and that UCMSCs were able to contribute to the regeneration of bone and blood vessels. Furthermore, no significant differences were identified between BMSCs and UCMSCs in terms of their bone regenerative effect.

Isolation and biological characteristics of multipotent mesenchymal stromal cells derived from chick embryo intestine

1. Over the past decade, rapid advancement in isolation methods for identifying markers of the once elusive intestinal stem cell (ISC) populations has laid the foundation for unravelling their complex interrelationships during homeostasis. Study on ISC in avian intestinal tissue might play a pivotal foundation for further studies on the epithelial-to-mesenchymal transition (EMT) in gastrointestinal disease and cell-based therapy as well as intestinal tissue engineering. 2. The following experiment isolated a population of fibroblast-like, plastic adhering cells derived from chick embryo intestine, showing a strong self-renewing and proliferative ability, which was maintained in vitro up to passage 25. The findings included growth characteristics, detected expression of cell surface markers and characterised the capability of these cells to differentiate towards the osteogenic, adipogenic, and chondrogenic cell lineages. 3. RT-PCR analysis showed that these cells from chick embryos expressed mesenchymal stromal cell markers CD44, CD90 and VIMENTIN as well as ISC-specific genes LGR5, MI1, SMOC2, BMI1, and HOPX. Immunofluorescence and flow cytometry confirmed this biology characterisation further. 4. In conclusion, cells were isolated from the intestine of 18-day-old chicken embryos that exhibited the biological characteristics of mesenchymal stromal cells as well as markers of intestinal stem cells. Our findings may provide a novel insight for in vitro cell culture and characteristics of ISCs in avian species, which may also indicate a benefit for obtaining cell source for intestinal tissue engineering as well as cell-based investigation for gastrointestinal disease and treatment.

Reconstruction of Regenerative Stem Cell Niche by Cell Aggregate Engineering

The niche plays critical roles in regulating functionality and determining regenerative outcomes of stem cells, for which establishment of favorable microenvironments is in demand in translational medicine. In recent years, the cell aggregate technology has shown immense potential to reconstruct a beneficial topical niche for stem cell-mediated regeneration, which has been recognized as a promising concept for high-density stem cell delivery with preservation of the self-produced, tissue-specific extracellular matrix microenvironments. Here, we describe the basic methodology of stem cell aggregate-based niche engineering and quality check indexes prior to application.