Single-cell sequencing technology in diabetic wound healing: New insights into the progenitors-based repair strategies

Diabetes mellitus (DM), an increasingly prevalent chronic metabolic disease, is characterised by prolonged hyperglycaemia, which leads to long-term health consequences. Although much effort has been put into understanding the pathogenesis of diabetic wounds, the underlying mechanisms remain unclear. The advent of single-cell RNA sequencing (scRNAseq) has revolutionised biological research by enabling the identification of novel cell types, the discovery of cellular markers, the analysis of gene expression patterns and the prediction of developmental trajectories. This powerful tool allows for an in-depth exploration of pathogenesis at the cellular and molecular levels. In this editorial, we focus on progenitor-based repair strategies for diabetic wound healing as revealed by scRNAseq and highlight the biological behaviour of various healing-related cells and the alteration of signalling pathways in the process of diabetic wound healing. ScRNAseq could not only deepen our understanding of the complex biology of diabetic wounds but also identify and validate new targets for intervention, offering hope for improved patient outcomes in the management of this challenging complication of DM.

Sinomenine increases osteogenesis in mice with ovariectomy-induced bone loss by modulating autophagy

BACKGROUND

A decreased autophagic capacity of bone marrow mesenchymal stromal cells (BMSCs) has been suggested to be an important cause of decreased osteogenic differentiation. A pharmacological increase in autophagy of BMSCs is a potential therapeutic option to increase osteoblast viability and ameliorate osteoporosis.

AIM

To explore the effects of sinomenine (SIN) on the osteogenic differentiation of BMSCs and the underlying mechanisms.

METHODS

For in vitro experiments, BMSCs were extracted from sham-treated mice and ovariectomized mice, and the levels of autophagy markers and osteogenic differentiation were examined after treatment with the appropriate concentrations of SIN and the autophagy inhibitor 3-methyladenine. In vivo, the therapeutic effect of SIN was verified by establishing an ovariectomy-induced mouse model and by morphological and histological assays of the mouse femur.

RESULTS

SIN reduced the levels of AKT and mammalian target of the rapamycin (mTOR) phosphorylation in the phosphatidylinositol 3-kinase (PI3K)/AKT/mTOR signaling pathway, inhibited mTOR activity, and increased autophagy ability of BMSCs, thereby promoting the osteogenic differentiation of BMSCs and effectively alleviating bone loss in ovariectomized mice in vivo.

CONCLUSION

The Chinese medicine SIN has potential for the treatment of various types of osteoporosis, bone homeostasis disorders, and autophagy-related diseases.

Hydrogel loaded with bone marrow stromal cell-derived exosomes promotes bone regeneration by inhibiting inflammatory responses and angiogenesis

BACKGROUND

Bone healing is a complex process involving early inflammatory immune regulation, angiogenesis, osteogenic differentiation, and biomineralization. Fracture repair poses challenges for orthopedic surgeons, necessitating the search for efficient healing methods.

AIM

To investigate the underlying mechanism by which hydrogel-loaded exosomes derived from bone marrow mesenchymal stem cells (BMSCs) facilitate the process of fracture healing.

METHODS

Hydrogels and loaded BMSC-derived exosome (BMSC-exo) gels were characterized to validate their properties. In vitro evaluations were conducted to assess the impact of hydrogels on various stages of the healing process. Hydrogels could recruit macrophages and inhibit inflammatory responses, enhance of human umbilical vein endothelial cell angiogenesis, and promote the osteogenic differentiation of primary cranial osteoblasts. Furthermore, the effect of hydrogel on fracture healing was confirmed using a mouse fracture model.

RESULTS

The hydrogel effectively attenuated the inflammatory response during the initial repair stage and subsequently facilitated vascular migration, promoted the formation of large vessels, and enabled functional vascularization during bone repair. These effects were further validated in fracture models.

CONCLUSION

We successfully fabricated a hydrogel loaded with BMSC-exo that modulates macrophage polarization and angiogenesis to influence bone regeneration.

Biological scaffold as potential platforms for stem cells: Current development and applications in wound healing

Wound repair is a complex challenge for both clinical practitioners and researchers. Conventional approaches for wound repair have several limitations. Stem cell-based therapy has emerged as a novel strategy to address this issue, exhibiting significant potential for enhancing wound healing rates, improving wound quality, and promoting skin regeneration. However, the use of stem cells in skin regeneration presents several challenges. Recently, stem cells and biomaterials have been identified as crucial components of the wound-healing process. Combination therapy involving the development of biocompatible scaffolds, accompanying cells, multiple biological factors, and structures resembling the natural extracellular matrix (ECM) has gained considerable attention. Biological scaffolds encompass a range of biomaterials that serve as platforms for seeding stem cells, providing them with an environment conducive to growth, similar to that of the ECM. These scaffolds facilitate the delivery and application of stem cells for tissue regeneration and wound healing. This article provides a comprehensive review of the current developments and applications of biological scaffolds for stem cells in wound healing, emphasizing their capacity to facilitate stem cell adhesion, proliferation, differentiation, and paracrine functions. Additionally, we identify the pivotal characteristics of the scaffolds that contribute to enhanced cellular activity.

Unveiling the role of hypoxia-inducible factor 2alpha in osteoporosis: Implications for bone health

BACKGROUND

Osteoporosis (OP) has become a major public health problem worldwide. Most OP treatments are based on the inhibition of bone resorption, and it is necessary to identify additional treatments aimed at enhancing osteogenesis. In the bone marrow (BM) niche, bone mesenchymal stem cells (BMSCs) are exposed to a hypoxic environment. Recently, a few studies have demonstrated that hypoxia-inducible factor 2alpha (HIF-2α) is involved in BMSC osteogenic differentiation, but the molecular mechanism involved has not been determined.

AIM

To investigate the effect of HIF-2α on the osteogenic and adipogenic differentiation of BMSCs and the hematopoietic function of hematopoietic stem cells (HSCs) in the BM niche on the progression of OP.

METHODS

Mice with BMSC-specific HIF-2α knockout (Prx1-Cre;Hif-2αfl/fl mice) were used for in vivo experiments. Bone quantification was performed on mice of two genotypes with three interventions: Bilateral ovariectomy, semilethal irradiation, and dexamethasone treatment. Moreover, the hematopoietic function of HSCs in the BM niche was compared between the two mouse genotypes. In vitro, the HIF-2α agonist roxadustat and the HIF-2α inhibitor PT2399 were used to investigate the function of HIF-2α in BMSC osteogenic and adipogenic differentiation. Finally, we investigated the effect of HIF-2α on BMSCs via treatment with the mechanistic target of rapamycin (mTOR) agonist MHY1485 and the mTOR inhibitor rapamycin.

RESULTS

The quantitative index determined by microcomputed tomography indicated that the femoral bone density of Prx1-Cre;Hif-2αfl/fl mice was lower than that of Hif-2αfl/fl mice under the three intervention conditions. In vitro, Hif-2αfl/fl mouse BMSCs were cultured and treated with the HIF-2α agonist roxadustat, and after 7 d of BMSC adipogenic differentiation, the oil red O staining intensity and mRNA expression levels of adipogenesis-related genes in BMSCs treated with roxadustat were decreased; in addition, after 14 d of osteogenic differentiation, BMSCs treated with roxadustat exhibited increased expression of osteogenesis-related genes. The opposite effects were shown for mouse BMSCs treated with the HIF-2α inhibitor PT2399. The mTOR inhibitor rapamycin was used to confirm that HIF-2α regulated BMSC osteogenic and adipogenic differentiation by inhibiting the mTOR pathway. Consequently, there was no significant difference in the hematopoietic function of HSCs between Prx1-Cre;Hif-2αfl/fl and Hif-2αfl/fl mice.

CONCLUSION

Our study showed that inhibition of HIF-2α decreases bone mass by inhibiting the osteogenic differentiation and increasing the adipogenic differentiation of BMSCs through inhibition of mTOR signaling in the BM niche.

Expansion of human umbilical cord derived mesenchymal stem cells in regenerative medicine

BACKGROUND

Stem cells are undifferentiated cells that possess the potential for self-renewal with the capacity to differentiate into multiple lineages. In humans, their limited numbers pose a challenge in fulfilling the necessary demands for the regeneration and repair of damaged tissues or organs. Studies suggested that mesenchymal stem cells (MSCs), necessary for repair and regeneration via transplantation, require doses ranging from 10 to 400 million cells. Furthermore, the limited expansion of MSCs restricts their therapeutic application.

AIM

To optimize a novel protocol to achieve qualitative and quantitative expansion of MSCs to reach the targeted number of cells for cellular transplantation and minimize the limitations in stem cell therapy protocols.

METHODS

Human umbilical cord (hUC) tissue derived MSCs were obtained and re-cultured. These cultured cells were subjected to the following evaluation procedures: Immunophenotyping, immunocytochemical staining, trilineage differentiation, population doubling time and number, gene expression markers for proliferation, cell cycle progression, senescence-associated β-galactosidase assay, human telomerase reverse transcriptase (hTERT) expression, mycoplasma, cytomegalovirus and endotoxin detection.

RESULTS

Analysis of pluripotent gene markers Oct4, Sox2, and Nanog in recultured hUC-MSC revealed no significant differences. The immunophenotypic markers CD90, CD73, CD105, CD44, vimentin, CD29, Stro-1, and Lin28 were positively expressed by these recultured expanded MSCs, and were found negative for CD34, CD11b, CD19, CD45, and HLA-DR. The recultured hUC-MSC population continued to expand through passage 15. Proliferative gene expression of Pax6, BMP2, and TGFb1 showed no significant variation between recultured hUC-MSC groups. Nevertheless, a significant increase (P < 0.001) in the mitotic phase of the cell cycle was observed in recultured hUC-MSCs. Cellular senescence markers (hTERT expression and β-galactosidase activity) did not show any negative effect on recultured hUC-MSCs. Additionally, quality control assessments consistently confirmed the absence of mycoplasma, cytomegalovirus, and endotoxin contamination.

CONCLUSION

This study proposes the development of a novel protocol for efficiently expanding stem cell population. This would address the growing demand for larger stem cell doses needed for cellular transplantation and will significantly improve the feasibility of stem cell based therapies.

Effects of high glucose and severe hypoxia on the biological behavior of mesenchymal stem cells at various passages

BACKGROUND

Mesenchymal stem cells (MSCs) have been extensively studied for therapeutic potential, due to their regenerative and immunomodulatory properties. Serial passage and stress factors may affect the biological characteristics of MSCs, but the details of these effects have not been recognized yet.

AIM

To investigate the effects of stress factors (high glucose and severe hypoxia) on the biological characteristics of MSCs at different passages, in order to optimize the therapeutic applications of MSCs.

METHODS

In this study, we investigated the impact of two stress conditions; severe hypoxia and high glucose on human adipose-tissue derived MSCs (hAD-MSCs) at passages 6 (P6), P8, and P10. Proliferation, senescence and apoptosis were evaluated measuring WST-1, senescence-associated beta-galactosidase, and annexin V, respectively.

RESULTS

Cells at P6 showed decreased proliferation and increased apoptosis under conditions of high glucose and hypoxia compared to control, while the extent of senescence did not change significantly under stress conditions. At P8 hAD-MSCs cultured in stress conditions had a significant decrease in proliferation and apoptosis and a significant increase in senescence compared to counterpart cells at P6. Cells cultured in high glucose at P10 had lower proliferation and higher senescence than their counterparts in the previous passage, while no change in apoptosis was observed. On the other hand, MSCs cultured under hypoxia showed decreased senescence, increased apoptosis and no significant change in proliferation when compared to the same conditions at P8.

CONCLUSION

These results indicate that stress factors had distinct effects on the biological processes of MSCs at different passages, and suggest that senescence may be a protective mechanism for MSCs to survive under stress conditions at higher passage numbers.

Gossypol acetic acid regulates leukemia stem cells by degrading LRPPRC via inhibiting IL-6/JAK1/STAT3 signaling or resulting mitochondrial dysfunction

BACKGROUND

Leukemia stem cells (LSCs) are found to be one of the main factors contributing to poor therapeutic effects in acute myeloid leukemia (AML), as they are protected by the bone marrow microenvironment (BMM) against conventional therapies. Gossypol acetic acid (GAA), which is extracted from the seeds of cotton plants, exerts anti-tumor roles in several types of cancer and has been reported to induce apoptosis of LSCs by inhibiting Bcl2.

AIM

To investigate the exact roles of GAA in regulating LSCs under different microenvironments and the exact mechanism.

METHODS

In this study, LSCs were magnetically sorted from AML cell lines and the CD34+CD38- population was obtained. The expression of leucine-rich pentatricopeptide repeat-containing protein (LRPPRC) and forkhead box M1 (FOXM1) was evaluated in LSCs, and the effects of GAA on malignancies and mitochondrial function were measured.

RESULTS

LRPPRC was found to be upregulated, and GAA inhibited cell proliferation by degrading LRPPRC. GAA induced LRPPRC degradation and inhibited the activation of interleukin 6 (IL-6)/janus kinase (JAK) 1/signal transducer and activator of transcription (STAT) 3 signaling, enhancing chemosensitivity in LSCs against conventional chemotherapies, including L-Asparaginase, Dexamethasone, and cytarabine. GAA was also found to downregulate FOXM1 indirectly by regulating LRPPRC. Furthermore, GAA induced reactive oxygen species accumulation, disturbed mitochondrial homeostasis, and caused mitochondrial dysfunction. By inhibiting IL-6/JAK1/STAT3 signaling via degrading LRPPRC, GAA resulted in the elimination of LSCs. Meanwhile, GAA induced oxidative stress and subsequent cell damage by causing mitochondrial damage.

CONCLUSION

Taken together, the results indicate that GAA might overcome the BMM protective effect and be considered as a novel and effective combination therapy for AML.

Interplay between mesenchymal stem cells and macrophages: Promoting bone tissue repair

The repair of bone tissue damage is a complex process that is well-orchestrated in time and space, a focus and difficulty in orthopedic treatment. In recent years, the success of mesenchymal stem cells (MSCs)-mediated bone repair in clinical trials of large-area bone defects and bone necrosis has made it a candidate in bone tissue repair engineering and regenerative medicine. MSCs are closely related to macrophages. On one hand, MSCs regulate the immune regulatory function by influencing macrophages proliferation, infiltration, and phenotype polarization, while also affecting the osteoclasts differentiation of macrophages. On the other hand, macrophages activate MSCs and mediate the multilineage differentiation of MSCs by regulating the immune microenvironment. The cross-talk between MSCs and macrophages plays a crucial role in regulating the immune system and in promoting tissue regeneration. Making full use of the relationship between MSCs and macrophages will enhance the efficacy of MSCs therapy in bone tissue repair, and will also provide a reference for further application of MSCs in other diseases.

Adipose-derived regenerative therapies for the treatment of knee osteoarthritis

Knee osteoarthritis is a degenerative condition with a significant disease burden and no disease-modifying therapy. Definitive treatment ultimately requires joint replacement. Therapies capable of regenerating cartilage could significantly reduce financial and clinical costs. The regenerative potential of mesenchymal stromal cells (MSCs) has been extensively studied in the context of knee osteoarthritis. This has yielded promising results in human studies, and is likely a product of immunomodulatory and chondroprotective biomolecules produced by MSCs in response to inflammation. Adipose-derived MSCs (ASCs) are becoming increasingly popular owing to their relative ease of isolation and high proliferative capacity. Stromal vascular fraction (SVF) and micro-fragmented adipose tissue (MFAT) are produced by the enzymatic and mechanical disruption of adipose tissue, respectively. This avoids expansion of isolated ASCs ex vivo and their composition of heterogeneous cell populations, including immune cells, may potentiate the reparative function of ASCs. In this editorial, we comment on a multicenter randomized trial regarding the efficacy of MFAT in treating knee osteoarthritis. We discuss the study's findings in the context of emerging evidence regarding adipose-derived regenerative therapies. An underlying mechanism of action of ASCs is proposed while drawing important distinctions between the properties of isolated ASCs, SVF, and MFAT.

Reveal more mechanisms of precondition mesenchymal stem cells inhibiting inflammation

Hypoxia can get more ability to inhibit inflammation. But how it impact on survival time of mesenchymal stem cells (MSCs) is confusing and how preconditioned MSCs inhibiting inflammation are partially known. Those issues decided the value of preconditioned MSCs by hypoxia.

Mesenchymal stem cells and their derived exosomes for the treatment of COVID-19

Coronavirus disease 2019 (COVID-19) is an acute respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). SARS-CoV-2 infection typically presents with fever and respiratory symptoms, which can progress to severe respiratory distress syndrome and multiple organ failure. In severe cases, these complications may even lead to death. One of the causes of COVID-19 deaths is the cytokine storm caused by an overactive immune response. Therefore, suppressing the overactive immune response may be an effective strategy for treating COVID-19. Mesenchymal stem cells (MSCs) and their derived exosomes (MSCs-Exo) have potent homing abilities, immunomodulatory functions, regenerative repair, and antifibrotic effects, promising an effective tool in treating COVID-19. In this paper, we review the main mechanisms and potential roles of MSCs and MSCs-Exo in treating COVID-19. We also summarize relevant recent clinical trials, including the source of cells, the dosage and the efficacy, and the clinical value and problems in this field, providing more theoretical references for the clinical use of MSCs and MSCs-Exo in the treatment of COVID-19.

Long-term outcome of stem cell transplantation with and without anti-tumor necrotic factor therapy in perianal fistula with Crohn's disease

BACKGROUND

Stem cell transplantation is a promising therapeutic option for curing perianal fistula in Crohn's disease (CD). Anti-tumor necrotic factor (TNF) therapy combined with drainage procedure is effective as well. However, previous studies are limited to proving whether the combination treatment of biologics and stem cell transplantation improves the effect of fistula closure.

AIM

This study aimed to evaluate the long-term outcomes of stem cell transplantation and compare Crohn's perianal fistula (CPF) closure rates after stem cell transplantation with and without anti-TNF therapy, and to identify the factors affecting CPF closure and recurrence.

METHODS

The patients with CD who underwent stem cell transplantation for treating perianal fistula in our institution between Jun 2014 and December 2022 were enrolled. Clinical data were compared according to anti-TNF therapy and CPF closure.

RESULTS

A total of 65 patients were included. The median age of females was 26 years (range: 21-31) and that of males was 29 (44.6%). The mean follow-up duration was 65.88 ± 32.65 months, and complete closure was observed in 50 (76.9%) patients. The closure rates were similar after stem cell transplantation with and without anti-TNF therapy (66.7% vs 81.6% at 3 year, P = 0.098). The patients with fistula closure had short fistulous tract and infrequent proctitis and anorectal stricture (P = 0.027, 0.002, and 0.008, respectively). Clinical factors such as complexity, number of fistulas, presence of concurrent abscess, and medication were not significant for closure. The cumulative 1-, 2-, and 3-year closure rates were 66.2%, 73.8%, and 75.4%, respectively.

CONCLUSION

Anti-TNF therapy does not increase CPF closure rates in patients with stem cell transplantation. However, both refractory and non-refractory CPF have similar closure rates after additional anti-TNF therapy. Fistulous tract length, proctitis, and anal stricture are risk factors for non-closure in patients with CPF after stem cell transplantation.

High glucose microenvironment and human mesenchymal stem cell behavior

High glucose (HG) culture conditions in vitro and persistent exposure to hyperglycemia in diabetes patients are detrimental to stem cells, analogous to any other cell type in our body. It interferes with diverse signaling pathways, i.e. mammalian target of rapamycin (mTOR)-phosphoinositide 3-kinase (PI3K)-Akt signaling, to impact physiological cellular functions, leading to low cell survival and higher cell apoptosis rates. While elucidating the underlying mechanism responsible for the apoptosis of adipose tissue-derived mesenchymal stem cells (MSCs), a recent study has shown that HG culture conditions dysregulate mTOR-PI3K-Akt signaling in addition to mitochondrial malfunctioning due to defective mitochondrial membrane potential (MtMP) that lowers ATP production. This organelle-level dysfunction energy-starves the cells and increases oxidative stress and ultrastructural abnormalities. Disruption of the mitochondrial electron transport chain produces an altered mitochondrial NAD+/NADH redox state as evidenced by a low NAD+/NADH ratio that primarily contributes to the reduced cell survival in HG. Some previous studies have also reported altered mitochondrial membrane polarity (causing hyperpolarization) and reduced mitochondrial cell mass, leading to perturbed mitochondrial homeostasis. The hostile microenvironment created by HG exposure creates structural and functional changes in the mitochondria, altering their bioenergetics and reducing their capacity to produce ATP. These are significant data, as MSCs are extensively studied for tissue regeneration and restoring their normal functioning in cell-based therapy. Therefore, MSCs from hyperglycemic donors should be cautiously used in clinical settings for cell-based therapy due to concerns of their poor survival rates and increased rates of post engraftment proliferation. As hyperglycemia alters the bioenergetics of donor MSCs, rectifying the loss of MtMP may be an excellent target for future research to restore the normal functioning of MSCs in hyperglycemic patients.

Self-assembly of differentiated dental pulp stem cells facilitates spheroid human dental organoid formation and prevascularization

BACKGROUND

The self-assembly of solid organs from stem cells has the potential to greatly expand the applicability of regenerative medicine. Stem cells can self-organise into microsized organ units, partially modelling tissue function and regeneration. Dental pulp organoids have been used to recapitulate the processes of tooth development and related diseases. However, the lack of vasculature limits the utility of dental pulp organoids.

AIM

To improve survival and aid in recovery after stem cell transplantation, we demonstrated the three-dimensional (3D) self-assembly of adult stem cell-human dental pulp stem cells (hDPSCs) and endothelial cells (ECs) into a novel type of spheroid-shaped dental pulp organoid in vitro under hypoxia and conditioned medium (CM).

METHODS

During culture, primary hDPSCs were induced to differentiate into ECs by exposing them to a hypoxic environment and CM. The hypoxic pretreated hDPSCs were then mixed with ECs at specific ratios and conditioned in a 3D environment to produce prevascularized dental pulp organoids. The biological characteristics of the organoids were analysed, and the regulatory pathways associated with angiogenesis were studied.

RESULTS

The combination of these two agents resulted in prevascularized human dental pulp organoids (Vorganoids) that more closely resembled dental pulp tissue in terms of morphology and function. Single-cell RNA sequencing of dental pulp tissue and RNA sequencing of Vorganoids were integrated to analyse key regulatory pathways associated with angiogenesis. The biomarkers forkhead box protein O1 and fibroblast growth factor 2 were identified to be involved in the regulation of Vorganoids.

CONCLUSION

In this innovative study, we effectively established an in vitro model of Vorganoids and used it to elucidate new mechanisms of angiogenesis during regeneration, facilitating the development of clinical treatment strategies.

Understanding host-graft crosstalk for predicting the outcome of stem cell transplantation

Mesenchymal stromal cells (MSCs) hold great promise for tissue regeneration in debilitating disorders. Despite reported improvements, the short-term outcomes of MSC transplantation, which is possibly linked to poor cell survival, demand extensive investigation. Disease-associated stress microenvironments further complicate outcomes. This debate underscores the need for a deeper understanding of the phenotypes of transplanted MSCs and their environment-induced fluctuations. Additionally, questions arise about how to predict, track, and comprehend cell fate post-transplantation. In vivo cellular imaging has emerged as a critical requirement for both short- and long-term safety and efficacy studies. However, translating preclinical imaging methods to clinical settings remains challenging. The fate and function of transplanted cells within the host environment present intricate challenges, including MSC engraftment, variability, and inconsistencies between preclinical and clinical data. The study explored the impact of high glucose concentrations on MSC survival in diabetic environments, emphasizing mitochondrial factors. Preserving these factors may enhance MSC survival, suggesting potential strategies involving genetic modification, biomaterials, and nanoparticles. Understanding stressors in diabetic patients is crucial for predicting the effects of MSC-based therapies. These multifaceted challenges call for a holistic approach involving the incorporation of large-scale data, computational disease modeling, and possibly artificial intelligence to enable deterministic insights.

Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells

BACKGROUND

The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years, which also may lead to some complications such as alveolar bone resorption or tooth root resorption. Low-intensity pulsed ultrasound (LIPUS), a noninvasive physical therapy, has been shown to promote bone fracture healing. It is also reported that LIPUS could reduce the duration of orthodontic treatment; however, how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear.

AIM

To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement (OTM) model and explore the underlying mechanisms.

METHODS

A rat model of OTM was established, and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections. In vitro, human bone marrow mesenchymal stem cells (hBMSCs) were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction, Western blot, alkaline phosphatase (ALP) staining, and Alizarin red staining. The expression of Yes-associated protein (YAP1), the actin cytoskeleton, and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA (siRNA) application via immunofluorescence.

RESULTS

The force treatment inhibited the osteogenic differentiation potential of hBMSCs; moreover, the expression of osteogenesis markers, such as type 1 collagen (COL1), runt-related transcription factor 2, ALP, and osteocalcin (OCN), decreased. LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force. Mechanically, the expression of LaminA/C, F-actin, and YAP1 was downregulated after force treatment, which could be rescued by LIPUS. Moreover, the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment. Consistently, LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo. The decreased expression of COL1, OCN, and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS.

CONCLUSION

LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis, which may be a promising strategy to reduce the orthodontic treatment process.

How mesenchymal stem cells transform into adipocytes: Overview of the current understanding of adipogenic differentiation

Mesenchymal stem cells (MSCs) are stem/progenitor cells capable of self-renewal and differentiation into osteoblasts, chondrocytes and adipocytes. The transformation of multipotent MSCs to adipocytes mainly involves two subsequent steps from MSCs to preadipocytes and further preadipocytes into adipocytes, in which the process MSCs are precisely controlled to commit to the adipogenic lineage and then mature into adipocytes. Previous studies have shown that the master transcription factors C/enhancer-binding protein alpha and peroxisome proliferation activator receptor gamma play vital roles in adipogenesis. However, the mechanism underlying the adipogenic differentiation of MSCs is not fully understood. Here, the current knowledge of adipogenic differentiation in MSCs is reviewed, focusing on signaling pathways, noncoding RNAs and epigenetic effects on DNA methylation and acetylation during MSC differentiation. Finally, the relationship between maladipogenic differentiation and diseases is briefly discussed. We hope that this review can broaden and deepen our understanding of how MSCs turn into adipocytes.

Evaluation of genetic response of mesenchymal stem cells to nanosecond pulsed electric fields by whole transcriptome sequencing

BACKGROUND

Mesenchymal stem cells (MSCs) modulated by various exogenous signals have been applied extensively in regenerative medicine research. Notably, nanosecond pulsed electric fields (nsPEFs), characterized by short duration and high strength, significantly influence cell phenotypes and regulate MSCs differentiation via multiple pathways. Consequently, we used transcriptomics to study changes in messenger RNA (mRNA), long noncoding RNA (lncRNA), microRNA (miRNA), and circular RNA expression during nsPEFs application.

AIM

To explore gene expression profiles and potential transcriptional regulatory mechanisms in MSCs pretreated with nsPEFs.

METHODS

The impact of nsPEFs on the MSCs transcriptome was investigated through whole transcriptome sequencing. MSCs were pretreated with 5-pulse nsPEFs (100 ns at 10 kV/cm, 1 Hz), followed by total RNA isolation. Each transcript was normalized by fragments per kilobase per million. Fold change and difference significance were applied to screen the differentially expressed genes (DEGs). Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses were performed to elucidate gene functions, complemented by quantitative polymerase chain reaction verification.

RESULTS

In total, 263 DEGs were discovered, with 92 upregulated and 171 downregulated. DEGs were predominantly enriched in epithelial cell proliferation, osteoblast differentiation, mesenchymal cell differentiation, nuclear division, and wound healing. Regarding cellular components, DEGs are primarily involved in condensed chromosome, chromosomal region, actin cytoskeleton, and kinetochore. From aspect of molecular functions, DEGs are mainly involved in glycosaminoglycan binding, integrin binding, nuclear steroid receptor activity, cytoskeletal motor activity, and steroid binding. Quantitative real-time polymerase chain reaction confirmed targeted transcript regulation.

CONCLUSION

Our systematic investigation of the wide-ranging transcriptional pattern modulated by nsPEFs revealed the differential expression of 263 mRNAs, 2 miRNAs, and 65 lncRNAs. Our study demonstrates that nsPEFs may affect stem cells through several signaling pathways, which are involved in vesicular transport, calcium ion transport, cytoskeleton, and cell differentiation.

O-linked β-N-acetylglucosaminylation may be a key regulatory factor in promoting osteogenic differentiation of bone marrow mesenchymal stromal cells

Cumulative evidence suggests that O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) plays an important regulatory role in pathophysiological processes. Although the regulatory mechanisms of O-GlcNAcylation in tumors have been gradually elucidated, the potential mechanisms of O-GlcNAcylation in bone metabolism, particularly, in the osteogenic differentiation of bone marrow mesenchymal stromal cells (BMSCs) remains unexplored. In this study, the literature related to O-GlcNAcylation and BMSC osteogenic differentiation was reviewed, assuming that it could trigger more scholars to focus on research related to O-GlcNAcylation and bone metabolism and provide insights into the development of novel therapeutic targets for bone metabolism disorders such as osteoporosis.

Silencing of Jumonji domain-containing 1C inhibits the osteogenic differentiation of bone marrow mesenchymal stem cells via nuclear factor-κB signaling

BACKGROUND

Osteoporosis is a common metabolic bone disorder induced by an imbalance between osteoclastic activity and osteogenic activity. During osteoporosis, bone mesenchymal stem cells (BMSCs) exhibit an increased ability to differentiate into adipocytes and a decreased ability to differentiate into osteoblasts, resulting in bone loss. Jumonji domain-containing 1C (JMJD1C) has been demonstrated to suppress osteoclastogenesis.

AIM

To examine the effect of JMJD1C on the osteogenesis of BMSCs and the potential underlying mechanism.

METHODS

BMSCs were isolated from mouse bone marrow tissues. Oil Red O staining, Alizarin red staining, alkaline phosphatase staining and the expression of adipogenic and osteogenic-associated genes were assessed to determine the differentiation of BMSCs. Bone marrow-derived macrophages (BMMs) were incubated with receptor activator of nuclear factor-kappa Β ligand to induce osteoclast differentiation, and osteoclast differentiation was confirmed by tartrate-resistant acid phosphatase staining. Other related genes were measured via reverse transcription coupled to the quantitative polymerase chain reaction and western blotting. Enzyme-linked immunosorbent assays were used to measure the levels of inflammatory cytokines, including tumor necrosis factor alpha, interleukin-6 and interleukin-1 beta.

RESULTS

The osteogenic and adipogenic differentiation potential of BMSCs isolated from mouse bone marrow samples was evaluated. JMJD1C mRNA and protein expression was upregulated in BMSCs after osteoblast induction, while p-nuclear factor-κB (NF-κB) and inflammatory cytokines were not significantly altered. Knockdown of JMJD1C repressed osteogenic differentiation and enhanced NF-κB activation and inflammatory cytokine release in BMSCs. Moreover, JMJD1C expression decreased during BMM osteoclast differentiation.

CONCLUSION

The JMJD1C/NF-κB signaling pathway is potentially involved in BMSC osteogenic differentiation and may play vital roles in the pathogenesis of osteoporosis.

Recent progress in hair follicle stem cell markers and their regulatory roles

Hair follicle stem cells (HFSCs) in the bulge are a multipotent adult stem cell population. They can periodically give rise to new HFs and even regenerate the epidermis and sebaceous glands during wound healing. An increasing number of biomarkers have been used to isolate, label, and trace HFSCs in recent years. Considering more detailed data from single-cell transcriptomics technology, we mainly focus on the important HFSC molecular markers and their regulatory roles in this review.

VX-509 attenuates the stemness characteristics of colorectal cancer stem-like cells by regulating the epithelial-mesenchymal transition through Nodal/Smad2/3 signaling

BACKGROUND

Colorectal cancer stem cells (CCSCs) are heterogeneous cells that can self-renew and undergo multidirectional differentiation in colorectal cancer (CRC) patients. CCSCs are generally accepted to be important sources of CRC and are responsible for the progression, metastasis, and therapeutic resistance of CRC. Therefore, targeting this specific subpopulation has been recognized as a promising strategy for overcoming CRC.

AIM

To investigate the effect of VX-509 on CCSCs and elucidate the underlying mechanism.

METHODS

CCSCs were enriched from CRC cell lines by in conditioned serum-free medium. Western blot, Aldefluor, transwell and tumorigenesis assays were performed to verify the phenotypic characteristics of the CCSCs. The anticancer efficacy of VX-509 was assessed in HCT116 CCSCs and HT29 CCSCs by performing cell viability analysis, colony formation, sphere formation, flow cytometry, and western blotting assessments in vitro and tumor growth, immunohistochemistry and immunofluorescence assessments in vivo.

RESULTS

Compared with parental cells, sphere cells derived from HCT116 and HT29 cells presented increased expression of stem cell transcription factors and stem cell markers and were more potent at promoting migration and tumorigenesis, demonstrating that the CRC sphere cells displayed CSC features. VX-509 inhibited the tumor malignant biological behavior of CRC-stem-like cells, as indicated by their proliferation, migration and clonality in vitro, and suppressed the tumor of CCSC-derived xenograft tumors in vivo. Besides, VX-509 suppressed the CSC characteristics of CRC-stem-like cells and inhibited the progression of epithelial-mesenchymal transition (EMT) signaling in vitro. Nodal was identified as the regulatory factor of VX-509 on CRC stem-like cells through analyses of differentially expressed genes and CSC-related database information. VX-509 markedly downregulated the expression of Nodal and its downstream phosphorylated Smad2/3 to inhibit EMT progression. Moreover, VX-509 reversed the dedifferentiation of CCSCs and inhibited the progression of EMT induced by Nodal overexpression.

CONCLUSION

VX-509 prevents the EMT process in CCSCs by inhibiting the transcription and protein expression of Nodal, and inhibits the dedifferentiated self-renewal of CCSCs.

Advances in the differentiation of pluripotent stem cells into vascular cells

Blood vessels constitute a closed pipe system distributed throughout the body, transporting blood from the heart to other organs and delivering metabolic waste products back to the lungs and kidneys. Changes in blood vessels are related to many disorders like stroke, myocardial infarction, aneurysm, and diabetes, which are important causes of death worldwide. Translational research for new approaches to disease modeling and effective treatment is needed due to the huge socio-economic burden on healthcare systems. Although mice or rats have been widely used, applying data from animal studies to human-specific vascular physiology and pathology is difficult. The rise of induced pluripotent stem cells (iPSCs) provides a reliable in vitro resource for disease modeling, regenerative medicine, and drug discovery because they carry all human genetic information and have the ability to directionally differentiate into any type of human cells. This review summarizes the latest progress from the establishment of iPSCs, the strategies for differentiating iPSCs into vascular cells, and the in vivo transplantation of these vascular derivatives. It also introduces the application of these technologies in disease modeling, drug screening, and regenerative medicine. Additionally, the application of high-tech tools, such as omics analysis and high-throughput sequencing, in this field is reviewed.

Human dental pulp stem/stromal cells in clinical practice

Dental pulp stem/stromal cells (DPSCs) are fibroblast-like, neural crest-derived, and multipotent cells that can differentiate into several lineages. They are relatively easy to isolate from healthy and inflamed pulps, with little ethical concerns and can be successfully cryopreserved and thawed. The therapeutic effects of DPSCs derived from animal or human sources have been extensively studied through in-vitro and in-vivo animal experiments and the findings indicated that DPSCs are effective not only for dental diseases but also for systemic diseases. Understanding that translational research is a critical step through which the fundamental scientific discoveries could be translated into applicable diagnostics and therapeutics that directly benefit humans, several clinical studies were carried out to generate evidence for the efficacy and safety of autogenous or allogeneic human DPSCs (hDPSCs) as a treatment modality for use in cell-based therapy, regenerative medicine/dentistry and tissue engineering. In clinical medicine, hDPSCs were effective for treating acute ischemic stroke and human exfoliated deciduous teeth-conditioned medium (SHED-CM) repaired vascular damage of the corpus cavernous, which is the main cause of erectile dysfunction. Whereas in clinical dentistry, autologous SHED was able to regenerate necrotic dental pulp after implantation into injured teeth, and micrografts enriched with autologous hDPSCs and collagen sponge were considered a treatment option for human intrabony defects. In contrast, hDPSCs did not add a significant regenerative effect when they were used for the treatment of post-extraction sockets. Large-scale clinical studies across diverse populations are still lacking to provide robust evidence on the safety and efficacy of hDPSCs as a new treatment option for various human diseases including dental-related problems.