Genetic Markers Can Predict Chondrogenic Differentiation Potential in Bone Marrow-Derived Mesenchymal Stromal Cells

Eosinophilic esophagitis drives tissue fibroblast regenerative programs toward pathologic dysfunction

BACKGROUND

Pathologic tissue remodeling with scarring and tissue rigidity has been demonstrated in inflammatory, autoimmune, and allergic diseases. Eosinophilic esophagitis (EoE) is an allergic disease that is diagnosed and managed by repeated biopsy procurement, allowing an understanding of tissue fibroblast dysfunction. While EoE-associated tissue remodeling causes clinical dysphagia, food impactions, esophageal rigidity, and strictures, molecular mechanisms driving these complications remain under investigation.

OBJECTIVE

We hypothesized that chronic EoE inflammation induces pathogenic fibroblasts with dysfunctional tissue regeneration and motility.

METHODS

We used single-cell RNA sequencing, fluorescence-activated cell sorting analysis, and fibroblast differentiation and migration assays to decipher the induced and retained pathogenic dysfunctions in EoE versus healthy esophageal fibroblasts.

RESULTS

Differentiation assays demonstrated that active EoE fibroblasts retain regenerative programs for rigid cells such as chondrocytes (P < .05) but lose healthy fibroblast capacity for soft cells such as adipocytes (P < .01), which was reflected in biopsy sample immunostaining (P < .01). EoE, but not healthy, fibroblasts show proinflammatory and prorigidity transcriptional programs on single-cell RNA sequencing. In vivo, regenerative fibroblasts reside in perivascular regions and near the epithelial junction, and during EoE, they have significantly increased migration (P < .01). Flow analysis and functional assays demonstrated that regenerative EoE fibroblasts have decreased surface CD73 expression and activity (both P < .05) compared to healthy controls, indicating aberrant adenosine triphosphate handling. EoE fibroblast dysfunctions were induced in healthy fibroblasts by reducing CD73 activity and rescued in EoE using adenosine repletion.

CONCLUSION

A normalization of perturbed extracellular adenosine triphosphate handling and CD73 could improve pathogenic fibroblast dysfunction and tissue regeneration in type 2 inflammatory diseases.

Disease-Associated Signatures Persist in Extracellular Vesicles from Reprogrammed Cells of Osteoarthritis Patients

Osteoarthritis (OA) is a prevalent joint disorder that lacks effective therapies to halt cartilage degeneration. Mesenchymal stromal cell (MSC)-derived small extracellular vesicles (sEVs) are being investigated as promising chondroprotective agents. Compared to primary MSCs, induced pluripotent stem cell (iPSC)-derived MSCs (MLCs) offer superior scalability and enhanced paracrine activity. The aim of this study was to explore the feasibility of using autologous MLC-derived sEVs as a potential therapeutic strategy for OA through the analysis of their protein cargo. iPSCs from an OA patient and a healthy donor were differentiated into MLCs. sEVs were isolated from these MLCs and characterized, with a particular focus on their protein cargo. Both iPSC lines were successfully differentiated into MLCs, which secreted sEVs with comparable size distributions and yields. The analysis of differentially expressed proteins revealed a high abundance of proteins associated with OA pathology and cartilage degradation in sEVs from OA MLCs compared to those from healthy MLCs. The persistence of OA-associated protein signatures in autologous MLC-derived sEVs may limit their therapeutic efficacy. These findings underscore the importance of carefully evaluating disease-specific protein profiles in sEVs for regenerative applications.

Wharton's Jelly Mesenchymal Stem Cells: Shaping the Future of Osteoarthritis Therapy with Advancements in Chitosan-Hyaluronic Acid Scaffolds

This review explores the potential of Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) in cartilage regeneration and osteoarthritis treatment. It covers key factors influencing chondrogenesis, including growth factors, cytokines, and hypoxia, focusing on precise timing. The effectiveness of three-dimensional cultures and scaffold-based strategies in chondrogenic differentiation is discussed. Specific biomaterials such as chitosan and hyaluronic acid are highlighted for tissue engineering. The document reviews clinical applications, incorporating evidence from animal research and early trials and molecular and histological assessments of chondrogenic differentiation processes. It addresses challenges and strategies for optimizing MSC-derived chondrocyte therapy, emphasizing the immunomodulatory properties of these cells. The review concludes as a comprehensive road map for future research and clinical applications in regenerative medicine.

GSTT1 as a Predictive Marker and Enhancer for Osteogenic Potential of Human Adipose-Derived Stromal/Stem Cells

Adipose-derived stromal/stem cells (ASCs) have been extensively studied as cell sources for regenerative medicine for bone because of their excellent proliferative capacity and the ability to obtain a large number of cells with minimal donor morbidity. On the other hand, the differentiation potential of ASCs is generally lower than that of bone marrow-derived stromal/stem cells and varies greatly depending on donors. In this study, we mined a marker that can predict the osteogenic potential of ASC clones and also investigated the usefulness of the molecule as the enhancer of osteogenic differentiation of ASCs as well as its mechanism of action. Through RNA-seq gene analysis, we discovered that GSTT1 (Glutathione S-transferase theta-1) was the most distinguished gene marker between highly osteogenic and poorly osteogenic ASC clones. Knockdown of GSTT1 in high osteogenic ASCs by siGSTT1 treatment reduced mineralized matrix formation. On the other hand, GSTT1 overexpression by GSTT1 transfection or GSTT1 recombinant protein treatment enhanced osteogenic differentiation of low osteogenic ASCs. Metabolomic analysis confirmed significant changes of metabolites related to bone differentiation in ASCs transfected with GSTT1. A high total antioxidant capacity, low levels of cellular reactive oxygen species, and increased GSH/GSSG ratios were also detected in GSTT1-transfected ASCs. When the in vivo effect of GSTT1-transfected ASCs on bone regeneration was investigated with segmental long-bone defect model in rats, bone regeneration was significantly better after implantation of GSTT1-transfected ASCs compared with that of control vector-transfected ASCs. In conclusion, GSTT1 can be a useful marker to screen the highly osteogenic ASC clones and also a therapeutic factor to enhance the osteogenic differentiation of poorly osteogenic ASC clones. © 2023 American Society for Bone and Mineral Research (ASBMR).

TGM2 accelerates migration and differentiation of BMSCs by activating Wnt/β-catenin signaling

BACKGROUND

Transglutaminase 2 (TGM2) is a gene previously reported to be associated with the differentiation of bone marrow mesenchymal stem cells (BMSCs). The study was developed to reveal the impact of TGM2 on the migration and differentiation of BMSCs.

METHODS

Cells were isolated from bone marrow of mice and then the surface antigens were identified by flow cytometry. Wound healing assays were conducted to assess the migratory ability of BMSCs. The mRNA levels of TGM2 and osteoblast-associated genes (ALP, OCN, and RUNX2) were subjected to RT-qPCR analysis, and protein levels of these genes as well as β-catenin were quantitated by western blotting. Alizarin red staining was conducted for detection of osteogenic ability. The activation of Wnt signaling was assessed by TOP/FOP flash assays.

RESULTS

Surface antigens were positively identified in MSCs, indicating good multidirectional differentiation ability of cells. TGM2 silencing suppressed BMSC migration while weakening mRNA and protein levels of osteoblast-associated genes. While TGM2 overexpression exerts the opposite impact on cell migration and expression levels of osteoblast-associated genes. Additionally, overexpressed TGM2 promotes the mineralization of BMSCs according to results of Alizarin red staining. Moreover, TGM2 activated the Wnt/β-catenin signaling, and DKK1 (an inhibitor of Wnt signaling) reversed the promoting influence of TGM2 on cell migration and differentiation.

CONCLUSION

TGM2 promotes the migration and differentiation of BMSCs via activation of the Wnt/β-catenin signaling.

Functional Heterogeneity of Bone Marrow Mesenchymal Stem Cell Subpopulations in Physiology and Pathology

Bone marrow mesenchymal stem cells (BMSCs) are multi-potent cell populations and are capable of maintaining bone and body homeostasis. The stemness and potential therapeutic effect of BMSCs have been explored extensively in recent years. However, diverse cell surface antigens and complex gene expression of BMSCs have indicated that BMSCs represent heterogeneous populations, and the natural characteristics of BMSCs make it difficult to identify the specific subpopulations in pathological processes which are often obscured by bulk analysis of the total BMSCs. Meanwhile, the therapeutic effect of total BMSCs is often less effective partly due to their heterogeneity. Therefore, understanding the functional heterogeneity of the BMSC subpopulations under different physiological and pathological conditions could have major ramifications for global health. Here, we summarize the recent progress of functional heterogeneity of BMSC subpopulations in physiology and pathology. Targeting tissue-resident single BMSC subpopulation offers a potentially innovative therapeutic strategy and improves BMSC effectiveness in clinical application.

Highly Porous Type II Collagen-Containing Scaffolds for Enhanced Cartilage Repair with Reduced Hypertrophic Cartilage Formation

The ability to regenerate damaged cartilage capable of long-term performance in an active joint remains an unmet clinical challenge in regenerative medicine. Biomimetic scaffold biomaterials have shown some potential to direct effective cartilage-like formation and repair, albeit with limited clinical translation. In this context, type II collagen (CII)-containing scaffolds have been recently developed by our research group and have demonstrated significant chondrogenic capacity using murine cells. However, the ability of these CII-containing scaffolds to support improved longer-lasting cartilage repair with reduced calcified cartilage formation still needs to be assessed in order to elucidate their potential therapeutic benefit to patients. To this end, CII-containing scaffolds in presence or absence of hyaluronic acid (HyA) within a type I collagen (CI) network were manufactured and cultured with human mesenchymal stem cells (MSCs) in vitro under chondrogenic conditions for 28 days. Consistent with our previous study in rat cells, the results revealed enhanced cartilage-like formation in the biomimetic scaffolds. In addition, while the variable chondrogenic abilities of human MSCs isolated from different donors were highlighted, protein expression analysis illustrated consistent responses in terms of the deposition of key cartilage extracellular matrix (ECM) components. Specifically, CI/II-HyA scaffolds directed the greatest cell-mediated synthesis and accumulation in the matrices of type II collagen (a principal cartilage ECM component), and reduced deposition of type X collagen (a key protein associated with hypertrophic cartilage formation). Taken together, these results provide further evidence of the capability of these CI/II-HyA scaffolds to direct enhanced and longer-lasting cartilage repair in patients with reduced hypertrophic cartilage formation.

Tracking of Oral and Craniofacial Stem Cells in Tissue Development, Regeneration, and Diseases

PURPOSE OF REVIEW

The craniofacial region hosts a variety of stem cells, all isolated from different sources of bone and cartilage. However, despite scientific advancements, their role in tissue development and regeneration is not entirely understood. The goal of this review is to discuss recent advances in stem cell tracking methods and how these can be advantageously used to understand oro-facial tissue development and regeneration.

RECENT FINDINGS

Stem cell tracking methods have gained importance in recent times, mainly with the introduction of several molecular imaging techniques, like optical imaging, computed tomography, magnetic resonance imaging, and ultrasound. Labelling of stem cells, assisted by these imaging techniques, has proven to be useful in establishing stem cell lineage for regenerative therapy of the oro-facial tissue complex. Novel labelling methods complementing imaging techniques have been pivotal in understanding craniofacial tissue development and regeneration. These stem cell tracking methods have the potential to facilitate the development of innovative cell-based therapies.

The Identification of Marker Genes for Predicting the Osteogenic Differentiation Potential of Mesenchymal Stromal Cells

Mesenchymal stromal cells (MSCs) have the potential to differentiate into a variety of mature cell types and are a promising source of regenerative medicine. The success of regenerative medicine using MSCs strongly depends on their differentiation potential. In this study, we sought to identify marker genes for predicting the osteogenic differentiation potential by comparing ilium MSC and fibroblast samples. We measured the mRNA levels of 95 candidate genes in nine ilium MSC and four fibroblast samples before osteogenic induction, and compared them with alkaline phosphatase (ALP) activity as a marker of osteogenic differentiation after induction. We identified 17 genes whose mRNA expression levels positively correlated with ALP activity. The chondrogenic and adipogenic differentiation potentials of jaw MSCs are much lower than those of ilium MSCs, although the osteogenic differentiation potential of jaw MSCs is comparable with that of ilium MSCs. To select markers suitable for predicting the osteogenic differentiation potential, we compared the mRNA levels of the 17 genes in ilium MSCs with those in jaw MSCs. The levels of 7 out of the 17 genes were not substantially different between the jaw and ilium MSCs, while the remaining 10 genes were expressed at significantly lower levels in jaw MSCs than in ilium MSCs. The mRNA levels of the seven similarly expressed genes were also compared with those in fibroblasts, which have little or no osteogenic differentiation potential. Among the seven genes, the mRNA levels of IGF1 and SRGN in all MSCs examined were higher than those in any of the fibroblasts. These results suggest that measuring the mRNA levels of IGF1 and SRGN before osteogenic induction will provide useful information for selecting competent MSCs for regenerative medicine, although the effectiveness of the markers is needed to be confirmed using a large number of MSCs, which have various levels of osteogenic differentiation potential.

Single-Cell RNA Sequencing of Bone Marrow Mesenchymal Stem Cells from the Elderly People

Background and Objectives

Bone marrow mesenchymal stem cells (BMSCs) show considerable promise in regenerative medicine. Many studies demonstrated that BMSCs cultured in vitro were highly heterogeneous and composed of diverse cell subpopulations, which may be the basis of their multiple biological characteristics. However, the exact cell subpopulations that make up BMSCs are still unknown.

Methods and Results

In this study, we used single-cell RNA sequencing (scRNA-Seq) to divide 6,514 BMSCs into three clusters. The number and corresponding proportion of cells in clusters 1 to 3 were 3,766 (57.81%), 1,720 (26.40%), and 1,028 (15.78%). The gene expression profile and function of the cells in the same cluster were similar. The vast majority of cells expressed the markers defining BMSCs by flow cytometry and gene expression analysis. Each cluster had at least 20 differentially expressed genes (DEGs). We conducted Gene Ontology enrichment analysis on the top 20 DEGs of each cluster and found that the three clusters had different functions, which were related to self-renewal, multilineage differentiation and cytokine secretion, respectively. In addition, the function of the top 20 DEGs of each cluster was checked by the National Center for Biotechnology Information gene database to further verify our hypothesis.

Conclusions

This study indicated that scRNA-Seq can be used to divide BMSCs into different subpopulations, demonstrating the heterogeneity of BMSCs.

Neuromedin B promotes chondrocyte differentiation of mesenchymal stromal cells via calcineurin and calcium signaling

Background

Articular cartilage is a complex tissue with poor healing capacities. Current approaches for cartilage repair based on mesenchymal stromal cells (MSCs) are often disappointing because of the lack of relevant differentiation factors that could drive MSC differentiation towards a stable mature chondrocyte phenotype.

Results

We used a large-scale transcriptomic approach to identify genes that are modulated at early stages of chondrogenic differentiation using the reference cartilage micropellet model. We identified several modulated genes and selected neuromedin B (NMB) as one of the early and transiently modulated genes. We found that the timely regulated increase of NMB was specific for chondrogenesis and not observed during osteogenesis or adipogenesis. Furthermore, NMB expression levels correlated with the differentiation capacity of MSCs and its inhibition resulted in impaired chondrogenic differentiation indicating that NMB is required for chondrogenesis. We further showed that NMB activated the calcineurin activity through a Ca²⁺-dependent signaling pathway.

Conclusion

NMB is a newly described chondroinductive bioactive factor that upregulates the key chondrogenic transcription factor Sox9 through the modulation of Ca²⁺ signaling pathway and calcineurin activity.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-021-00695-1.

Novel application of bergapten and quercetin with anti-bacterial, osteogenesis-potentiating, and anti-inflammation tri-effects

The bacteria-mediated inflammatory conditions adversely affect the osseointegration process of endosseous implants, which can even lead to implant malfunction or failure. Local drug delivery has been designed to exert anti-inflammatory and antibacterial activities, but whether this strategy has an effect on the compromised osseointegration under inflammation has rarely been studied. The present study focused on the osteoinductive efficacy of two known phytoestrogens [bergapten (BP) and quercetin (QE)] on implant sites under multiple bacteria-infected conditions in situ. Furthermore, the gene expression profiles of rat bone mesenchymal stem cells (rBMSCs) treated with BP and QE in the presence of Porphyromonas gingivalis-derived lipopolysaccharide were identified. The results showed that both drugs, especially QE, had significant potentiating effects on promoting osteogenic differentiation of rBMSCs, resisting multiple pathogens, and reducing inflammatory activity. Meanwhile, RNA sequencing analysis highlighted the enriched gene ontology terms and the differentially expressed genes (Vps25, Il1r2, Csf3, Efemp1, and Ccl20) that might play essential roles in regulating the above tri-effects, which provided the basis for the drug delivery system to be used as a novel therapeutic strategy for integrating peri-implant health. Overall, our study confirmed that QE appeared to outperform BP in osteogenesis and bacterial killing but not in anti-inflammation. Moreover, both drugs possess favorable tri-effects and can serve as the pivotal agents for the drug delivery system to boost osseointegration at inflammatory implant sites.

Regenerative medicine for radiation emergencies

Hiroshima University is a 'medical institution for tertiary radiation emergencies' and a 'medical support organization as a part of the International Atomic Emergency Agency Emergency Preparedness Response-Response and Assistance Network (IAEA EPR-RANET)'. To establish a system of regenerative medicine for radiation emergencies with treatment by implantation of various types of cells derived from induced pluripotent stem (iPS) cells, it is necessary to establish methods of defense against and treatment for radiation-induced damage from nuclear power plant accidents and nuclear terrorism. It is also necessary to develop cell therapy, cellular repair technology and regenerative biotechnology as regenerative medicine for radiation emergencies. Such applications have not been established yet. To develop a regenerative medical system, by using the existing one, for radiation emergencies, we will attempt to manage the cell-processing center to establish a safe and secured iPS cell bank for radiation medicine. By using this iPS cell bank as the central leverage, we will develop an education program for radiation emergency medicine and construct a network of regenerative medicine for radiation emergency medicine.

Chondrocytes respond both anabolically and catabolically to impact loading generally considered non-injurious

We aimed to determine the longitudinal effects of low-energy (generally considered non-injurious) impact loading on (1) chondrocyte proliferation, (2) chondroprogenitor cell activity, and (3) EGFR signaling. In an in vitro study, we assessed 127 full-thickness, cylindrical osteochondral plugs of bovine cartilage undergoing either single, uniaxial unconfined impact loads with energy densities in the range of 1.5-3.2mJ/mm³ or no impact (controls). We quantified cell responses at two, 24, 48, and 72 h via immunohistochemical labeling of Ki67, Sox9, and pEGFR antibodies. We compared strain, stress, and impact energy density as predictors for mechanotransductive responses from cells, and fit significant correlations using linear regressions. Our study demonstrates that low-energy mechanical impacts (1.5-3.2mJ/mm³) generally stimulate time-dependent anabolic responses in the superficial zone of articular cartilage and catabolic responses in the middle and deep zones. We also found that impact energy density is the most consistent predictor of cell responses to low-energy impact loading. These spatial and temporal changes in chondrocyte behavior result directly from low-energy mechanical impacts, revealing a new level of mechanotransductive sensitivity in chondrocytes not previously appreciated.

Spatial Distributions, Characteristics, and Applications of Craniofacial Stem Cells

Stem cells play an irreplaceable role in the development, homeostasis, and regeneration of the craniofacial bone. Multiple populations of tissue-resident craniofacial skeletal stem cells have been identified in different stem cell niches, including the cranial periosteum, jawbone marrow, temporomandibular joint, cranial sutures, and periodontium. These cells exhibit self-renewal and multidirectional differentiation abilities. Here, we summarized the properties of craniofacial skeletal stem cells, based on their spatial distribution. Specifically, we focused on the in vivo genetic fate mapping of stem cells, by exploring specific stem cell markers and observing their lineage commitment in both the homeostatic and regenerative states. Finally, we discussed their application in regenerative medicine.

FAK Deficiency in Bone Marrow Stromal Cells Alters Their Homeostasis and Drives Abnormal Proliferation and Differentiation of Haematopoietic Stem Cells

Emerging evidence indicates that in myelodysplastic syndromes (MDS), the bone marrow (BM) microenvironment may also contribute to the ineffective, malignant haematopoiesis in addition to the intrinsic abnormalities of haematopoietic stem precursor cells (HSPCs). The BM microenvironment influences malignant haematopoiesis through indirect mechanisms, but the processes by which the BM microenvironment directly contributes to MDS initiation and progression have not yet been elucidated. Our previous data showed that BM-derived stromal cells (BMSCs) from MDS patients have an abnormal expression of focal adhesion kinase (FAK). In this study, we characterise the morpho-phenotypic features and the functional alterations of BMSCs from MDS patients and in FAK knock-downed HS-5 cells. The decreased expression of FAK or its phosphorylated form in BMSCs from low-risk (LR) MDS directly correlates with BMSCs' functional deficiency and is associated with a reduced level of haemoglobin. The downregulation of FAK in HS-5 cells alters their morphology, proliferation, and differentiation capabilities and impairs the expression of several adhesion molecules. In addition, we examine the CD34+ healthy donor (HD)-derived HSPCs' properties when co-cultured with FAK-deficient BMSCs. Both abnormal proliferation and the impaired erythroid differentiation capacity of HD-HSPCs were observed. Together, these results demonstrate that stromal adhesion mechanisms mediated by FAK are crucial for regulating HSPCs' homeostasis.