The elusive nature and function of mesenchymal stem cells. Nat Rev Mol Cell Biol. 2011;12:126-131. [PMID: 21253000 DOI: 10.1038/nrm3049]

Molecular gene signature of circulating stromal/stem cells

The human skeleton is renewed and regenerated throughout life, by a cellular process known as bone remodeling. Stem cells are clono-genic cells that are capable of differentiation into multiple mature cell types (multipotency), and simultaneously replenishing stem cell pool (self-renewal), which allows them to sustain tissue development and maintenance. Circulating mesenchymal stromal/stem cells (MSCs), are mobile adult stem cells with specific gene expression profiling, as well as enhanced mitochondrial remodeling as a promising source for personalized cell and gene therapy. A global LGR5-associated genetic interaction network highlights the functional organization and molecular phenotype of circulating MSCs.

Soft Pneumatic Device Designed to Mimic the Periosteal Environment for Regulating the Fate of Mesenchymal Stem Cells

Replicating the complex mechanical forces of muscle movement and fluid flow in in vitro cell culture systems is crucial for understanding cell differentiation and development. However, previous research focused on cell differentiation on static micro/nanotextures without a force field or flat 2-dimensional substrates under a continuous in-plane mechanical force. In this study, cell differentiation is reported using a spatial geometric platform that can periodically modulate complex mechanical forces through a custom-made soft pneumatic device (SPD) to mimic the interfaces between periosteum and interstitial fluid. To elucidate fluidic dynamics and cell fates relevant to bone physiology, the platform exhibited distinct functional responses based on mechanical force levels: low mechanotransduction induced mesenchymal stem/progenitor cells differentiation into osteoprogenitor cells (≈1.5-fold increase in osteo-differentiation), while high mechanotransduction resulted in structural disruptions resembling cell detachment without protein degradation (≈2-fold increase in effective cell detachment). Numerical simulations of SPD elucidated the principal mechanical components for programmable cell differentiation and detachment by deconvoluting the in-plane and out-of-plane mechanical forces of the SPD complex mode. This study offers comprehensive and novel insights into the correlation between mechanical forces and cell differentiation, recovery, and injury in organisms.

Clinical translation of mesenchymal stem cells in ischemic heart failure: Challenges and future perspectives

Myocardial infarction (MI) with resulting congestive heart failure is one of the leading causes of death worldwide. Current therapies for treating MI, such as devices, traditional medicine, and surgeries, come with many limitations as patients in their final stages of heart failure have little chances of experiencing any reversible changes. In recent decades, Mesenchymal stem cell (MSC) based therapy has become one of the most popular and rapidly developing fields in treating MI. Their supremacy for clinical applications is partially due to their unique properties and encouraging pre-clinical outcomes in various animal disease models. However, the majority of clinical trials registered for MSC therapy for diverse human diseases, including MI, have fallen short of expectations. This review intends to discuss the recent advances in the clinical application of using MSCs for cardiac repair and discuss challenges facing the clinical translation of MSCs for cardiac regeneration such as restoration of endothelial-cardiomyocyte crosstalk, immunomodulation and immune rejection, poor homing and migration, as well as low retention and survival. Furthermore, we will discuss recent strategies being investigated to help overcome some of these challenges.

Correlation between serum high-density lipoprotein cholesterol and bone mineral density in vitamin D-deficient populations

INTRODUCTION

To investigate the relationship between serum high-density lipoprotein (HDL) cholesterol and bone mineral density (BMD) in vitamin D-deficient population.

MATERIALS AND METHODS

This study was a cross-sectional study. From January to December 2020, 2583 middle-aged and older adult aged 40 and above were randomly selected in the Health Management Center of the Affiliated Hospital of Guizhou Medical University for health examination and questionnaire survey. The correlation was determined by Pearson correlation method, and the independent correlation was analyzed by multiple linear regression. The receiver Operating characteristic (ROC) curve estimates HDL-C cutoff levels for predicting osteoporosis risk.

RESULTS

The prevalence of osteoporosis in the study population was 11.4%, the overall prevalence of 25 (OH) D deficiency was 78.2%. There was no correlation between HDL-C and BMD of lumbar spine, femoral neck and total hip in normal vitamin D group (P > 0.05). HDL-C in the deficient group was negatively correlated with BMD of lumbar spine and femoral neck (P < 0.05), but not with BMD of total hip. Serum HDL-C concentration increased with the progression of osteoporosis. When serum 25 (OH) D level was lower than normal level, HDL-C ≥ 1.215 mmol/L was an independent predictor of osteoporosis (sensitivity = 75%, specificity = 53%, Area = 0.625).

CONCLUSIONS

HDL-C was inversely associated with BMD in the lumbar spine and femoral neck in people aged 40 years and older with vitamin D deficiency. When serum HDL-C concentration ≥ 1.215 mmol/L, it can better predict the occurrence of osteoporosis.

Engineered Extracellular Vesicles from Antler Blastema Progenitor Cells: A Therapeutic Choice for Spinal Cord Injury

Deer antler blastema progenitor cells (ABPCs) are promising for regenerative medicine due to their role in annual antler regeneration, the only case of complete organ regeneration in mammals. ABPC-derived signals show great potential for promoting regeneration in tissues with limited natural regenerative ability. Our findings demonstrate the capability of extracellular vesicles from ABPCs (EVsABPC) to repair spinal cord injury (SCI), a condition with low regenerative capacity. EVsABPC significantly enhanced the proliferation of neural stem cells (NSCs) and activated neuronal regenerative potential, resulting in a 5.2-fold increase in axonal length. Additionally, EVsABPC exhibited immunomodulatory effects, shifting macrophages from M1 to M2. Engineered with activated cell-penetrating peptides (ACPPs), EVsABPC significantly outperformed EVs from rat bone marrow stem cells (EVsBMSC) and neural stem cells (EVsNSC), promoting a 1.3-fold increase in axonal growth, a 30.6% reduction in neuronal apoptosis, and a 2.6-fold improvement in motor function recovery. These findings support ABPC-derived EVs as a promising therapeutic candidate for SCI repair.

3D bioprinting approaches for enhancing stem cell-based neural tissue regeneration

Three-dimensional (3D) bioprinting holds immense promise for advancing stem cell research and developing novel therapeutic strategies in the field of neural tissue engineering and disease modeling. This paper critically analyzes recent breakthroughs in 3D bioprinting, specifically focusing on its application in these areas. We comprehensively explore the advantages and limitations of various 3D printing methods, the selection and formulation of bioink materials tailored for neural stem cells, and the incorporation of nanomaterials with dual functionality, enhancing the bioprinting process and promoting neurogenesis pathways. Furthermore, the paper reviews the diverse range of stem cells employed in neural bioprinting research, discussing their potential applications and associated challenges. We also introduce the emerging field of 4D bioprinting, highlighting current efforts to develop time-responsive constructs that improve the integration and functionality of bioprinted neural tissues. In short, this manuscript aims to provide a comprehensive understanding of this rapidly evolving field. It underscores the transformative potential of 3D and 4D bioprinting technologies in revolutionizing stem cell research and paving the way for novel therapeutic solutions for neurological disorders and injuries, ultimately contributing significantly to the advancement of regenerative medicine. STATEMENT OF SIGNIFICANCE: This comprehensive review critically examines the current bioprinting research landscape, highlighting efforts to overcome key limitations in printing technologies-improving cell viability post-printing, enhancing resolution, and optimizing cross-linking efficiencies. The continuous refinement of material compositions aims to control the spatiotemporal delivery of therapeutic agents, ensuring better integration of transplanted cells with host tissues. Specifically, the review focuses on groundbreaking advancements in neural tissue engineering. The development of next-generation bioinks, hydrogels, and scaffolds specifically designed for neural regeneration complexities holds the potential to revolutionize treatments for debilitating neural conditions, especially when nanotechnologies are being incorporated. This review offers the readers both a comprehensive analysis of current breakthroughs and an insightful perspective on the future trajectory of neural tissue engineering.

Can cell-cultured meat from stem cells pave the way for sustainable alternative protein?

As the global population grows, the demand for food and animal-derived products rises significantly, posing a notable challenge to the progress of society in general. Alternative protein production may adequately address such a challenge, and cell-based meat production emerges as a promising solution. This review investigates methodologies for in vitro myogenesis and adipogenesis from stem cells (adult, embryonic, or induced pluripotent stem cells - iPSCs) across different animal species, as well as the remaining challenges for scalability, the possibility of genetic modification, along with safety concerns regarding the commercialization of cell-cultured meat. Regarding such complexities, interdisciplinary approaches will be vital for assessing the potential of cell-cultured meat as a sustainable protein source, mimicking the sensory and nutritional attributes of conventional livestock meat whilst meeting the demands of a growing global population while mitigating environmental impacts.

Functionalized Periosteum-Derived Microsphere-Hydrogel with Sequential Release of E7 Short Peptide/miR217 for Large Bone Defect Repairing

Large bone defects are still a persistent challenge in orthopedics. The availability limitations and associated complications of autologous and allogeneic bone have prompted an increasing reliance on tissue engineering and regenerative medicine. In this study, we developed an injectable scaffold combining an acellular extracellular periosteal matrix hydrogel with poly(d,l-lactate-co-glycol-acetate) microspheres loaded with the E7 peptide and miR217 (miR217/E7@MP-GEL). Characterization of the composites included morphological analysis by scanning electron microscopy, degradation and swelling tests, in vitro and in vivo biological evaluation, and the biological activity evaluation of mesenchymal stem cells (MSCs) through their effects on cell recruitment, proliferation, and osteogenic differentiation. The designed hydrogels demonstrated good physical and chemical properties that are cytocompatible and suitable for cell recruitment. In vitro studies confirmed the high biological activity of the release agent, which markedly enhanced the proliferation and osteogenic differentiation of MSCs. In vivo application to a rat model of a femur defect exhibited a significant increase in bone volume and density over 7 weeks, resulting in enhanced bone regeneration. Acellular periosteum-based hydrogels combined with the E7 peptide and miR217-loaded poly(d,l-lactate-co-glycol-acetate) microspheres can promote effective bone regeneration through the recruitment, proliferation, and osteogenic differentiation of MSCs, which provides a promising approach for the treatment of large bone defects.

Aucubin Promotes BMSCs Proliferation and Differentiation of Postmenopausal Osteoporosis Patients by Regulating Ferroptosis and BMP2 Signalling

Postmenopausal osteoporosis (PMOP) is a chronic systemic bone metabolism disorder. Promotion in the patterns of human bone marrow mesenchymal stem cells (hBMSCs) differentiation towards osteoblasts contributes to alleviating osteoporosis. Aucubin, a natural compound isolated from the well-known herbal medicine Eucommia, was previously shown to possess various pharmacological effects. However, its effects on hBMSCs of PMOP patients are unknown. The aim of this present research was to investigate the impact and underlying process of aucubin on cell proliferation and osteogenic differentiation in hBMSCs isolated from PMOP patients. The ability of aucubin to inhibit the ferroptosis induced by erastin in hBMSCs was detected; ROS production, ferrous ion levels, SOD, MDA, and GPX activities were tested by using commercial kits. Next, ALP staining, ARS staining, RT-qPCR, RNA-sequencing, and Western blot were applied for determining the mRNA and protein expression levels associated with the osteogenesis of hBMSCs. The study also explored the involvement of BMP2/Smads signalling in aucubin promoting the osteogenesis of hBMSCs and evaluated the effects of aucubin intervention on osteoporosis using an ovariectomised rat model. The results indicated that aucubin significantly inhibited ROS generation and oxidative stress induced by erastin and protected against ferroptosis in hBMSCs. Additionally, aucubin facilitated osteogenic differentiation of hBMSCs by activating the BMP2/SMADs pathway and attenuated the progression of osteoporosis in OVX rats, suggesting a potential therapeutic benefit for postmenopausal osteoporosis (PMOP).

Validation of an automated quality control method to test sterility of two advanced therapy medicinal products: Mesenchymal stromal cells and their extracellular vesicles

Mesenchymal stromal cells are multipotent cells present in various tissues that are widely studied for relevant therapeutic potential due to their paracrine immunomodulatory and tissue regenerating properties. Many mesenchymal stromal cell-based products are under investigation for the treatment of different clinical conditions. Recently, the therapeutic potential of the extracellular vesicles released by these cells has been under focus, with emphasis on clinical translation. Sterility testing during manufacture and before the final release of the advanced therapy medicinal products to markets is a critical quality control measure. Therefore, analytical methods for sterility testing in addition to complying with pharmacopeial standards must validate the adequacy of each product and evaluate matrix interference. Here, an automated system for sterility control of reagents used in the bioprocessing of mesenchymal stromal cells and their extracellular vesicles was validated. Reagents (culture media, antibiotics, and excipients in the final product) were inoculated with 10 or 50 colony forming units of microorganisms in BACTEC™ Peds Plus™ T/F aerobic/anaerobic bottles. Under aerobic conditions (BACTEC™ Peds Plus™ T/F aerobic bottles), microbial growth was detected within an acceptable incubation time according to regulatory guidelines. The results of this study corroborate other studies that use automated sterility testing as an alternative to the manual USP<71> compendial method to detect microorganisms close to the limit of detection within an acceptable incubation time.

Induced Pluripotent Stem Cells in Birds: Opportunities and Challenges for Science and Agriculture

The only cells in an organism that could do any other sort of cell until 2006 (except sperm or egg) were known as embryonic stem cells, ESC [...].

Cell therapy in kidney diseases: advancing treatments for renal regeneration

Kidney diseases, including acute kidney injury (AKI) and chronic kidney disease (CKD), pose a significant global health challenge, with high morbidity and mortality rates driven by rising prevalence of risk factors such as diabetes and hypertension. Current therapeutic strategies are often limited, prompting the exploration of advanced cell therapies as potential solutions. This review provides a comprehensive overview of the state of cell therapies in kidney disease, tracing the progression from preclinical studies to clinical applications. Recent studies highlited that cell-based interventions offer kidney-protective properties through mechanisms such as paracrine signaling, immune modulation, and direct tissue integration, demonstrating potential in both AKI and CKD settings. Despite promising results, challenges remain in optimizing cell therapy protocols, including cell sourcing, delivery methods, and long-term outcomes. Finally, the review addresses on efforts to enhance cell function, optimize dosing, and refine delivery techniques to improve clinical outcomes in kidney disease management.

Anti-necroptotic effects of human Wharton's jelly-derived mesenchymal stem cells in skeletal muscle cell death model via secretion of GRO-α

Human mesenchymal stem cells (hMSCs) have therapeutic applications and potential for use in regenerative medicine. However, the use of hMSCs in research and clinical medicine is limited by a lack of information pertaining to their donor-specific functional attributes. In this study, we compared the characteristics of same-donor derived placenta (PL) and Wharton's jelly (WJ)-derived hMSCs, we also compared their mechanism of action in a skeletal muscle disease in vitro model. The same-donor-derived hWJ- and hPL-MSCs exhibited typical hMSC characteristics. However, GRO-α was differentially expressed in hWJ- and hPL-MSCs. hWJ-MSCs, which secreted a high amount of GRO-α, displayed a higher ability to inhibit necroptosis in skeletal muscle cells than hPL-MSCs. This demonstrates the anti-necroptotic therapeutic effect of GRO-α in the skeletal muscle cell death model. Furthermore, GRO-α also exhibited the anti-necroptotic effect in a Duchenne muscular dystrophy (DMD) mouse model. Considering their potential to inhibit necroptosis in skeletal muscle cells, hWJ-MSCs and the derived GRO-α are novel treatment options for skeletal muscle diseases such as DMD.

Targeting the mTOR-Autophagy Axis: Unveiling Therapeutic Potentials in Osteoporosis

Osteoporosis (OP) is a widespread age-related disorder marked by decreased bone density and increased fracture risk, presenting a significant public health challenge. Central to the development and progression of OP is the dysregulation of the mechanistic target of the rapamycin (mTOR)-signaling pathway, which plays a critical role in cellular processes including autophagy, growth, and proliferation. The mTOR-autophagy axis is emerging as a promising therapeutic target due to its regulatory capacity in bone metabolism and homeostasis. This review aims to (1) elucidate the role of mTOR signaling in bone metabolism and its dysregulation in OP, (2) explore the interplay between mTOR and autophagy in the context of bone cell activity, and (3) assess the therapeutic potential of targeting the mTOR pathway with modulators as innovative strategies for OP treatment. By examining the interactions among autophagy, mTOR, and OP, including insights from various types of OP and the impact on different bone cells, this review underscores the complexity of mTOR's role in bone health. Despite advances, significant gaps remain in understanding the detailed mechanisms of mTOR's effects on autophagy and bone cell function, highlighting the need for comprehensive clinical trials to establish the efficacy and safety of mTOR inhibitors in OP management. Future research directions include clarifying mTOR's molecular interactions with bone metabolism and investigating the combined benefits of mTOR modulation with other therapeutic approaches. Addressing these challenges is crucial for developing more effective treatments and improving outcomes for individuals with OP, thereby unveiling the therapeutic potentials of targeting the mTOR-autophagy axis in this prevalent disease.

Mesenchymal stem cell application in pulmonary disease treatment with emphasis on their interaction with lung-resident immune cells

Due to the vital importance of the lungs, lung-related diseases and their control are very important. Severe inflammatory responses mediated by immune cells were among the leading causes of lung tissue pathology and damage during the COVID-19 pandemic. In addition, uncontrolled immune cell responses can lead to lung tissue damage in other infectious and non-infectious diseases. It is essential to control immune responses in a way that leads to homeostasis. Immunosuppressive drugs only suppress inflammatory responses and do not affect the homeostasis of reactions. The therapeutic application of mesenchymal stem cells (MSCs), in addition to restoring immune homeostasis, can promote the regeneration of lung tissue through the production of growth factors and differentiation into lung-related cells. However, the communication between MSCs and immune cells after treatment of pulmonary diseases is essential, and investigating this can help develop a clinical perspective. Different studies in the clinical phase showed that MSCs can reverse fibrosis, increase regeneration, promote airway remodeling, and reduce damage to lung tissue. The proliferation and differentiation potential of MSCs is one of the mechanisms of their therapeutic effects. Furthermore, they can secrete exosomes that affect the function of lung cells and immune cells and change their function. Another important mechanism is that MSCs reduce harmful inflammatory responses through communication with innate and adaptive immune cells, which leads to a shift of the immune system toward regulatory and hemostatic responses.

Novel Gene Biomarkers Specific to Human Mesenchymal Stem Cells Isolated from Bone Marrow

In this paper, we present a comparative analysis of the transcriptomic profile of three different human cell types: hematopoietic stem cells (HSCs), bone marrow-derived mesenchymal stem cells (MSCs) and fibroblasts (FIBs). The work aims to identify unique genes that are differentially expressed as specific markers of bone marrow-derived MSCs, and to achieve this undertakes a detailed analysis of three independent datasets that include quantification of the global gene expression profiles of three primary cell types: HSCs, MSCs and FIBs. A robust bioinformatics method, called GlobalTest, is used to assess the specific association between one or more genes expressed in a sample and the outcome variable, that is, the 'cell type' provided as a single univariate response. This outcome variable is predicted for each sample tested, based on the expression profile of the specific genes that are used as input to the test. The precision of the tests is calculated along with the statistical sensitivity and specificity for each gene in each dataset, yielding four genes that mark MSCs with high accuracy. Among these, the best performer is the protein-coding gene Transgelin (TAGLN, Gene ID: 6876) (with a Positive Predictive Value > 0.96 and FDR < 0.001), which identifies MSCs better than any of the currently used standard markers: ENG (CD105), THY1 (CD90) or NT5E (CD73). The results are validated by RT-qPCR, providing novel gene biomarkers specific for human MSCs.

Human dental pulp stem cells modulate pro-inflammatory macrophages both through cell-to-cell contact and paracrine signaling

Introduction

Macrophages play a key role in most of the inflammatory diseases such as Rheumatoid Arthritis (RA), but the mechanism underlying their pathogenesis is still under study. Among stem cells, human dental pulp stem cells (hDPSCs) have attracted attention due to their easy accessibility and immunomodulatory properties, making them a promising adjuvant therapy. In this study, we aimed to evaluate the capacity of hDPSCs to modulate the phenotypes of primary human macrophages. Additionally, we sought to observe the differences induced on macrophages when cultured directly with hDPSCs or through a cell culture insert, mimicking the paracrine communication pathway.

Methods

Monocytes, isolated from buffy coats, were differentiated into pro-inflammatory M1 and anti-inflammatory M2 macrophages. Subsequently, they were cultured with hDPSCs either directly or via a cell-culture insert for 48 hours. Finally, they were analyzed for protein, gene expression, cytokines levels and immunofluorescence.

Results

In our study, we have demonstrated that, hDPSCs, even without priming, can reduce TNFα levels and enhancing IL-10 release in pro-inflammatory macrophages, both through direct contact and paracrine signaling. Furthermore, we found that their effects are more pronounced when in cell-to-cell contact through the decrease of NF-kB and COX-2 expression and of CD80/PD-L1 colocalization. HDPSCs, when in contact with macrophages, showed enhanced expression of NF-kB, COX-2, ICAM-1, PD-L1, FAS-L, TNFα and IFNγ.

Conclusion

We showed that hDPSCs exert immunomodulatory effects on pro-inflammatory macrophages, with cell-to-cell contact yielding a more pronounced outcome compared to paracrine signaling. Our work highlights the immunomodulatory properties of hDPSCs on activated pro-inflammatory macrophages and the potential therapeutic role in inflamed tissue.

Human pancreatic islet-derived stromal cells reveal combined features of mesenchymal stromal cells and pancreatic stellate cells

BACKGROUND

Mesenchymal stromal cells (MSCs) are recognized for their potential in regenerative medicine, attributed to their multipotent differentiation capabilities and immunomodulatory properties. Despite this potential, the classification and detailed characterization of MSCs, especially those derived from specific tissues like the pancreas, remains challenging leading to a proliferation of terminology in the literature. This study aims to address these challenges by providing a thorough characterization of human pancreatic islets-derived mesenchymal stromal cells (hPD-MSCs).

METHODS

hPD-MSCs were isolated from donor islets using enzymatic digestion, immortalized through lentiviral transduction of human telomerase reverse transcriptase (hTERT). Cells were characterized by immunostaining, flow cytometry and multilineage differentiation potential into adipogenic and osteogenic lineages. Further a transcriptomic analysis was done to compare the gene expression profiles of hPD-MSCs with other mesenchymal cells.

RESULTS

We show that hPD-MSCs express the classical MSC features, including morphological characteristics, surface markers expression (CD90, CD73, CD105, CD44, and CD106) and the ability to differentiate into both adipogenic and osteogenic lineages. Furthermore, transcriptomic analysis revealed distinct gene expression profiles, showing notable similarities between hPD-MSCs and pancreatic stellate cells (PSCs). The study also identified specific genes that distinguish hPD-MSCs from MSCs of other origins, including genes associated with pancreatic function (e.g., ISL1) and neural development (e.g., NPTX1, ZNF804A). A novel gene with an unknown function (ENSG00000286190) was also discovered.

CONCLUSIONS

This study enhances the understanding of hPD-MSCs, demonstrating their unique characteristics and potential applications in therapeutic strategies. The identification of specific gene expression profiles differentiates hPD-MSCs from other mesenchymal cells and opens new avenues for research into their role in pancreatic function and neural development.

Perinatal nicotine vaping exposure induces pro-myofibroblastic phenotype in rat bone marrow-derived mesenchymal stem cells

Perinatal nicotine exposure via tobacco smoking results in increased proclivity to chronic lung disease (CLD); however, the underlying molecular mechanisms remain incompletely understood. We previously demonstrated that in addition to nicotine's direct effects on the developing lung, there are also adverse molecular alterations in bone marrow-derived mesenchymal stem cells (BMSCs), which are vital to lung injury repair. Whether perinatal nicotine exposure via electronic-cigarette (e-cig) vaping also adversely affects BMSCs is unknown. This is highly relevant due to marked increase in e-cig vaping including by pregnant women. Hypothesizing that perinatal nicotine exposure via e-cig vaping predisposes BMSCs to a pro-myofibroblastic phenotype, pregnant rat dams were exposed to fresh air (control), vehicle (e-cig without nicotine), or e-cig (e-cig with nicotine) daily during pregnancy and lactation. At postnatal day 21, offspring BMSCs were isolated and studied for cell proliferation, migration, wound healing response, and expression of key Wnt and PPARγ signaling intermediates (β-catenin, LEF-1, PPARγ, ADRP and C/EBPα) and myogenic markers (fibronectin, αSMA, calponin) proteins using immunoblotting. Compared to controls, perinatal e-cig exposure resulted in significant decrease in BMSC proliferation, migration, and wound healing response. The expression of key Wnt signaling intermediates (β-catenin, LEF-1) and myogenic markers (fibronectin, αSMA, calponin) increased significantly, while PPARγ signaling intermediates (PPARγ, ADRP, and C/EBPα) decreased significantly. Based on these data, we conclude that perinatally e-cig exposed BMSCs demonstrate pro-myofibroblastic phenotype and impaired injury-repair potential, indicating a potentially similar susceptibility to CLD following perinatal nicotine exposure via vaping as seen following parenteral perinatal nicotine exposure.

Mesenchymal stem cells as future treatment for cardiovascular regeneration and its challenges

Cardiovascular diseases (CVDs), particularly stroke and myocardial infarction (MI) contributed to the leading cause of death annually among the chronic diseases globally. Despite the advancement of technology, the current available treatments mainly served as palliative care but not treating the diseases. However, the discovery of mesenchymal stem cells (MSCs) had gained a consideration to serve as promising strategy in treating CVDs. Recent evidence also showed that MSCs are the strong candidate to be used as stem cell therapy involving cardiovascular regeneration due to its cardiomyogenesis, anti-inflammatory and immunomodulatory properties, antifibrotic effects and neovascularization capacity. Besides, MSCs could be used for cellular cardiomyoplasty with its transdifferentiation of MSCs into cardiomyocytes, paracrine effects, microvesicles and exosomes as well as mitochondrial transfer. The safety and efficacy of utilizing MSCs have been described in well-established preclinical and clinical studies in which the accomplishment of MSCs transplantation resulted in further improvement of the cardiac function. Tissue engineering could enhance the desired properties and therapeutic effects of MSCs in cardiovascular regeneration by genome-editing, facilitating the cell delivery and retention, biomaterials-based scaffold, and three-dimensional (3D)-bioprinting. However, there are still obstacles in the use of MSCs due to the complexity and versatility of MSCs, low retention rate, route of administration and the ethical and safety issues of the use of MSCs. The aim of this review is to highlight the details of therapeutic properties of MSCs in treating CVDs, strategies to facilitate the therapeutic effects of MSCs through tissue engineering and the challenges faced using MSCs. A comprehensive review has been done through PubMed and National Center for Biotechnology Information (NCBI) from the year of 2010 to 2021 based on some specific key terms such as 'mesenchymal stem cells in cardiovascular disease', 'mesenchymal stem cells in cardiac regeneration', 'mesenchymal stem cells facilitate cardiac repairs', 'tissue engineering of MSCs' to include relevant literature in this review.

Recent Advances in Hydrogel Technology in Delivering Mesenchymal Stem Cell for Osteoarthritis Therapy

Osteoarthritis (OA), a chronic joint disease affecting over 500 million individuals globally, is characterized by the destruction of articular cartilage and joint inflammation. Conventional treatments are insufficient for repairing damaged joint tissue, necessitating novel therapeutic approaches. Mesenchymal stem cells (MSCs), with their potential for differentiation and self-renewal, hold great promise as a treatment for OA. However, challenges such as MSC viability and apoptosis in the ischemic joint environment hinder their therapeutic effectiveness. Hydrogels with biocompatibility and degradability offer a three-dimensional scaffold that support cell viability and differentiation, making them ideal for MSC delivery in OA treatment. This review discusses the pathological features of OA, the properties of MSCs, the challenges associated with MSC therapy, and methods for hydrogel preparation and functionalization. Furthermore, it highlights the advantages of hydrogel-based MSC delivery systems while providing insights into future research directions and the clinical potential of this approach.

Ovarian function in patients with systemic lupus erythematosus: Pathogenesis, drug application and prospective therapies

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease in which multiple organs are damaged that prevails in fertile women. Currently, glucocorticoids and immunosuppressants are widely used to treat SLE patients. However, ovarian dysfunction occurs following the use of these drugs in women with SLE. Here, we summarize recent progress in terms of understanding ovarian injury, the effects of drug application and strategies to improve ovarian function in women with SLE. This review could be helpful to precisely cure SLE in women desiring to have offspring.

Sources and applications of endothelial seed cells: a review

Endothelial cells (ECs) are widely used as donor cells in tissue engineering, organoid vascularization, and in vitro microvascular model development. ECs are invaluable tools for disease modeling and drug screening in fundamental research. When treating ischemic diseases, EC engraftment facilitates the restoration of damaged blood vessels, enhancing therapeutic outcomes. This article presents a comprehensive overview of the current sources of ECs, which encompass stem/progenitor cells, primary ECs, cell lineage conversion, and ECs derived from other cellular sources, provides insights into their characteristics, potential applications, discusses challenges, and explores strategies to mitigate these issues. The primary aim is to serve as a reference for selecting suitable EC sources for preclinical research and promote the translation of basic research into clinical applications.

Alternative therapeutic strategies in diabetes management

Diabetes is a heterogeneous metabolic disease characterized by elevated blood glucose levels resulting from the destruction or malfunction of pancreatic β cells, insulin resistance in peripheral tissues, or both, and results in a non-sufficient production of insulin. To adjust blood glucose levels, diabetic patients need exogenous insulin administration together with medical nutrition therapy and physical activity. With the aim of improving insulin availability in diabetic patients as well as ameliorating diabetes comorbidities, different strategies have been investigated. The first approaches included enhancing endogenous β cell activity or transplanting new islets. The protocol for this kind of intervention has recently been optimized, leading to standardized procedures. It is indicated for diabetic patients with severe hypoglycemia, complicated by impaired hypoglycemia awareness or exacerbated glycemic lability. Transplantation has been associated with improvement in all comorbidities associated with diabetes, quality of life, and survival. However, different trials are ongoing to further improve the beneficial effects of transplantation. Furthermore, to overcome some limitations associated with the availability of islets/pancreas, alternative therapeutic strategies are under evaluation, such as the use of mesenchymal stem cells (MSCs) or induced pluripotent stem cells for transplantation. The cotransplantation of MSCs with islets has been successful, thus providing protection against proinflammatory cytokines and hypoxia through different mechanisms, including exosome release. The use of induced pluripotent stem cells is recent and requires further investigation. The advantages of MSC implantation have also included the improvement of diabetes-related comorbidities, such as wound healing. Despite the number of advantages of the direct injection of MSCs, new strategies involving biomaterials and scaffolds have been developed to improve the efficacy of mesenchymal cell delivery with promising results. In conclusion, this paper offered an overview of new alternative strategies for diabetes management while highlighting some limitations that will need to be overcome by future approaches.

Extracellular Vesicles Derived from Type 2 Diabetic Mesenchymal Stem Cells Induce Endothelial Mesenchymal Transition under High Glucose Conditions Through the TGFβ/Smad3 Signaling Pathway

Type 2 diabetes mellitus (T2DM) is associated with endothelial dysfunction, which results in delayed wound healing. Mesenchymal stem cells (MSCs) play a vital role in supporting endothelial cells (ECs) and promoting wound healing by paracrine effects through their secretome-containing extracellular vesicles. We previously reported the impaired wound healing ability of adipose tissue-derived MSC from T2DM donors; however, whether extracellular vesicles isolated from T2DM adipose tissue-derived MSCs (dEVs) exhibit altered functions in comparison to those derived from healthy donors (nEVs) is still unclear. In this study, we found that nEVs induced EC survival and angiogenesis, whereas dEVs lost these abilities. In addition, under high glucose conditions, nEV protected ECs from endothelial-mesenchymal transition (EndMT), whereas dEV significantly induced EndMT by activating the transforming growth factor-β/Smad3 signaling pathway, which impaired the tube formation and in vivo wound healing abilities of ECs. Interestingly, the treatment of dEV-internalized ECs with nEVs rescued the induced EndMT effects. Of note, the internalization of nEV into T2DM adipose tissue-derived MSC resulted in the production of an altered n-dEV, which inhibited EndMT and supported the survival of T2DM db/db mice from severe wounds. Taken together, our findings suggest the role of dEV in endothelial dysfunction and delayed wound healing in T2DM by the promotion of EndMT. Moreover, nEV treatment can be considered a promising candidate for cell-free therapy to protect ECs in T2DM.

The secretome from human-derived mesenchymal stem cells augments the activity of antitumor plant extracts in vitro

Cancer is understood as a multifactorial disease that involve multiple cell types and phenotypes in the tumor microenvironment (TME). The components of the TME can interact directly or via soluble factors (cytokines, chemokines, growth factors, extracellular vesicles, etc.). Among the cells composing the TME, mesenchymal stem cells (MSCs) appear as a population with debated properties since it has been seen that they can both promote or attenuate tumor progression. For various authors, the main mechanism of interaction of MSCs is through their secretome, the set of molecules secreted into the extracellular milieu, recruiting, and influencing the behavior of other cells in inflammatory environments where they normally reside, such as wounds and tumors. Natural products have been studied as possible cancer treatments, appealing to synergisms between the molecules in their composition; thus, extracts obtained from Petiveria alliacea (Anamu-SC) and Caesalpinia spinosa (P2Et) have been produced and studied previously on different models, showing promising results. The effect of plant extracts on the MSC secretome has been poorly studied, especially in the context of the TME. Here, we studied the effect of Anamu-SC and P2Et extracts in the human adipose-derived MSC (hAMSC)-tumor cell interaction as a TME model. We also investigated the influence of the hAMSC secretome, in combination with these natural products, on tumor cell hallmarks such as viability, clonogenicity, and migration. In addition, hAMSC gene expression and protein synthesis were evaluated for some key factors in tumor progression in the presence of the extracts by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Multiplex, respectively. It was found that the presence of the hAMSC secretome did not affect the cytotoxic or clonogenicity-reducing activities of the natural extracts on cancer cells, and even this secretome can inhibit the migration of these tumor cells, in addition to the fact that the profile of molecules can be modified by natural products. Overall, our findings demonstrate that hAMSC secretome participation in TME interactions can favor the antitumor activities of natural products.

Versatile strategies for adult neurogenesis: avenues to repair the injured brain

Brain injuries due to trauma or stroke are major causes of adult death and disability. Unfortunately, few interventions are effective for post-injury repair of brain tissue. After a long debate on whether endogenous neurogenesis actually happens in the adult human brain, there is now substantial evidence to support its occurrence. Although neurogenesis is usually significantly stimulated by injury, the reparative potential of endogenous differentiation from neural stem/progenitor cells is usually insufficient. Alternatively, exogenous stem cell transplantation has shown promising results in animal models, but limitations such as poor long-term survival and inefficient neuronal differentiation make it still challenging for clinical use. Recently, a high focus was placed on glia-to-neuron conversion under single-factor regulation. Despite some inspiring results, the validity of this strategy is still controversial. In this review, we summarize historical findings and recent advances on neurogenesis strategies for neurorepair after brain injury. We also discuss their advantages and drawbacks, as to provide a comprehensive account of their potentials for further studies.

Biofabrication paradigms in corneal regeneration: bridging bioprinting techniques, natural bioinks, and stem cell therapeutics

Corneal diseases are a major cause of vision loss worldwide. Traditional methods like corneal transplants from donors are effective but face challenges like limited donor availability and the risk of graft rejection. Therefore, new treatment methods are essential. This review examines the growing field of bioprinting and biofabrication in corneal tissue engineering. We begin by discussing various bioprinting methods such as stereolithography, inkjet, and extrusion printing, highlighting their strengths and weaknesses for eye-related uses. We also explore how biological tissues are made suitable for bioprinting through a process called decellularization, which can be achieved using chemical, physical, or biological methods. The review then looks at natural materials, known as bioinks, used in bioprinting. We focus on materials like gelatin, collagen, fibrin, chitin, chitosan, silk fibroin, and alginate, examining their mechanical and biological properties. The importance of hydrogel scaffolds, particularly those based on collagen and other materials, is also discussed in the context of repairing corneal tissue. Another key area we cover is the use of stem cells in corneal regeneration. We pay special attention to limbal epithelial stem cells and mesenchymal stromal cells, highlighting their roles in this process. The review concludes with an overview of the latest advancements in corneal tissue bioprinting, from early techniques to advanced methods of delivering stem cells using bioengineered materials. In summary, this review presents the current state and future potential of bioprinting and biofabrication in creating functional corneal tissues, highlighting new developments and ongoing challenges with a view towards restoring vision.

Investigation of healing strategies in a rat corneal opacity model with polychromatic light and stem cells injection

Corneal opacities are a major cause of vision loss worldwide. However, the current therapies are suboptimal to manage the corneal wound healing process. Therefore, there is an obvious need to develop new treatment strategies that are efficient in promoting wound healing in patients with severe corneal disorders. In this study, we investigated and compared the efficacy of adipose-derived mesenchymal stem cells (ADMSCs) and photobiomodulation (PBM) with polychromatic light in the NIR (600-1200 nm) alone and in combination, on corneal opacity, inflammatory response, and tissue architecture in a rat corneal opacity model created by mechanical injury. All animals were divided into four groups randomly following the injury: injury only (no treatment), ADMSCs treatment, PBM treatment and combined (ADMSCs+PBM) treatment (n = 12 eyes per group). At the 10th and 30th day following injury, corneal opacity formation, neovascularization, and corneal thickness were assessed. On the 30th day the harvested corneas were analyzed by transmission electron microscopy (TEM), histological evaluation, immunohistochemical (IHC) staining and real-time polymerase chain reaction (RT-PCR). On day 30, the corneal opacity score, neovascularization grade, and corneal thickness in all treatment groups were significantly lower in comparison with the untreated injured corneas. The TEM imaging and H&E staining together clearly revealed a significant enhancement in corneal regeneration with improved corneal microenvironment and reduced vascularization in the combined administration of PBM and ADMSCs compared to treatment of PBM and ADMSCs alone. In addition, the IHC staining, and RT-PCR analysis supported our hypothesis that combining ADMSCs therapy with PBM alleviated the inflammatory response, and significantly decreased scar formation compared to either ADMSCs or PBM alone during the corneal wound healing.

Investigation of the differentiation potential of pericyte cells as an alternative source of mesenchymal stem cells

BACKGROUND

The mesenchymal stem cells (MSCs) with characterized by their multipotency and capacity to differentiate into various tissue cell types, have led to their incorporation in regenerative medicine research. However, the limited numbers of MSCs in the human body and their diverse differentiation capabilities in tissues highlight the need for exploring alternative regenerative cell sources. In this study, therefore, we conducted molecular level examinations to determine whether pericytes, specialized cell communities situated near blood vessels, could serve as a substitute for human bone marrow-derived mesenchymal stem cells (hBM-MSCs). In this context, the potential application of pericytes surrounds the vessels when MSCs are insufficient for functional purposes.

METHODS

The pericytes utilized in this investigation were derived from the placenta and characterized at the third passage. Similarly, the hBM-MSCs were also characterized at the third passage. The pluripotent properties of the two cell types were assessed at the gene expression level. Thereafter, both pericytes and hBM-MSCs were directed towards adipogenic, osteogenic and chondrogenic differentiation. The cells in both groups were examined on days 7, 14, and, 21 and their differentiation status was compared both immunohistochemically and through gene expression analysis.

RESULTS

Upon comparing the pluripotency characteristics of placental pericytes and hBM-MSCs, it was discovered that there was a substantial upregulation of the pluripotency genes FoxD3, Sox2, ZPF42, UTF1, and, Lin28 in both cell types. However, no significant expression of the genes Msx1, Nr6a1, Pdx1, and, GATA6 was observed in either cell type. It was also noted that pericytes differentiate into adipogenic, osteogenic and, chondrogenic lineages similar to hBM-MSCs.

DISCUSSION

As a result, it has been determined that pericytes exhibit high differentiation and proliferation properties similar to those of MSCs, and therefore can be considered a suitable alternative cell source for regenerative medicine and tissue engineering research, in cases where MSCs are not available or insufficient. It is notable that pericytes have been suggested as a potential substitute in studies where MSCs are lacking.

Single cell RNA-seq identifies a FOS/JUN-related monocyte signature associated with clinical response of heart failure patients with mesenchymal stem cell therapy

Heart failure (HF) is a serious global health issue that demands innovative treatment approaches. In this study, we collected samples from 4 HF patients before and after MSC therapy and performed scRNA-seq. After the MSC therapy, the proportion of CD14+ monocytes decreased significantly in both the treatment response and non-response groups, with a more pronounced decrease in the treatment response group. The therapy-response and non-response group were clearly separated in the UMAP plot, while the CD14+ monocytes in the therapy-response group before and after MSC therapy were very similar, but there were significant differences in the non-response group. By further performing NMF analysis, we identified 11 subsets of CD14+ monocytes. More importantly, we identified a therapy-related CD14+ monocyte subpopulation. The predictive model based on CD14+ monocytes constructed by machine learning algorithms showed good performance. Moreover, genes such as FOS were highly enriched in the therapy-related CD14+ monocytes. The SCENIC analysis revealed potential regulatory factors for this treatment-responsive CD14+ monocytes, and FOS/JUN were identified as potential core indicators/regulators. Finally, HF patients were divided into three groups by NMF analysis, and the therapy-responsive CD14+ monocyte characteristics were differentially activated among the three groups. Together, this study identifies treatment-responsive CD14+ monocytes as a crucial biomarker for assessing the suitability of MSC therapy and determining which HF patients could benefit from it. This provides new clues for further investigating the therapeutic mechanisms of MSC therapy, offering beneficial insights for personalized treatment and improving prognosis in HF patients.

Combined Placental Mesenchymal Stem Cells with Guided Nanoparticles Effective Against Diabetic Nephropathy in Mouse Model

Background

Diabetic nephropathy (DN) is a prevalent complication of diabetes mellitus and constitutes the primary cause of mortality in affected patients. Previous studies have shown that placental mesenchymal stem cells (PL-MSCs) can alleviate kidney dysfunction in animal models of DN. However, the limited ability of mesenchymal stem cells (MSCs) to home to damaged sites restricts their therapeutic potential. Enhancing the precision of PL-MSCs' homing to target tissues is therefore vital for the success of cell therapies in treating DN.

Methods

We developed Fe3O4 coated polydopamine nanoparticle (NP)-internalized MSCs and evaluated their therapeutic effectiveness in a mouse model of streptozotocin- and high-fat diet-induced DN, using an external magnetic field.

Results

Our study confirmed that NPs were effectively internalized into PL-MSCs without compromising their intrinsic stem cell properties. The magnetic targeting of PL-MSCs notably improved their homing to the kidney tissues in mice with DN, resulting in enhanced kidney function compared to the transplantation of PL-MSCs alone. Furthermore, the anti-inflammatory and antifibrotic attributes of PL-MSCs played a role in the recovery of kidney function and structure.

Conclusion

These results demonstrate that magnetically targeted therapy using PL-MSCs is a promising approach for treating diabetic nephropathy.

Protective role of stem cells in POI: Current status and mechanism of action, a review article

Premature ovarian insufficiency (POI) has far-reaching consequences on women's life quality. Due to the lack of full recognition of the etiology and complexity of this disease, there is no appropriate treatment for infected patients. Recently, stem cell therapy has attracted the attention of regenerative medicine scholars and offered promising outcomes for POI patients. Several kinds of stem cells, such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs) have been used for the treatment of ovarian diseases. However, their potential protective mechanisms are still unknown. Undoubtedly, a better understanding of the therapeutic molecular and cellular mechanisms of stem cells will address uncover strategies to increase their clinical application for multiple disorders such as POI. This paper describes a detailed account of the potential properties of different types of stem cells and provides a comprehensive review of their protective mechanisms, particularly MSC, in POI disorder. In addition, ongoing challenges and several strategies to improve the efficacy of MSC in clinical use are addressed. Therefore, this review will provide proof-of-concept for further clinical application of stem cells in POI.

Decoding the multifaceted signatures and transcriptomic characteristics of stem cells derived from apical papilla and dental pulp of human supernumerary teeth

Supernumerary teeth are advantaged sources for high-quality stem cell preparation from both apical papilla (SCAP-Ss) and dental pulp (DPSCs). However, the deficiency of the systematic and detailed comparison of the biological and transcriptomic characteristics of the aforementioned stem cells largely hinders their application in regenerative medicine. Herein, we collected supernumerary teeth for SCAP-S and DPSC isolation and identification by utilizing multiple biological tests (e.g., growth curve, cell cycle and apoptosis, adipogenic and osteogenic differentiation, and quantitative real-time polymerase chain reaction). Furthermore, we took advantage of transcriptome sequencing and multifaceted bioinformatic analyses to dissect the similarities and diversities between them. In this study, we found that SCAP-Ss and DPSCs showed indistinctive signatures in morphology and immunophenotypes, whereas with diversity in cell vitality and multi-lineage differentiation as well as gene expression profiling and differentially expressed genes-associated gene ontology and signaling pathways. Collectively, our data indicated the diversity of the multifaceted signatures of human supernumerary teeth-derived stem cells both at the cellular and molecular levels, which also supplied new references for SCAP-Ss serving as splendid alternative stem cell sources for regenerative medicine purposes.

Morphology-based deep learning approach for predicting adipogenic and osteogenic differentiation of human mesenchymal stem cells (hMSCs)

Human mesenchymal stem cells (hMSCs) are multipotent progenitor cells with the potential to differentiate into various cell types, including osteoblasts, chondrocytes, and adipocytes. These cells have been extensively employed in the field of cell-based therapies and regenerative medicine due to their inherent attributes of self-renewal and multipotency. Traditional approaches for assessing hMSCs differentiation capacity have relied heavily on labor-intensive techniques, such as RT-PCR, immunostaining, and Western blot, to identify specific biomarkers. However, these methods are not only time-consuming and economically demanding, but also require the fixation of cells, resulting in the loss of temporal data. Consequently, there is an emerging need for a more efficient and precise approach to predict hMSCs differentiation in live cells, particularly for osteogenic and adipogenic differentiation. In response to this need, we developed innovative approaches that combine live-cell imaging with cutting-edge deep learning techniques, specifically employing a convolutional neural network (CNN) to meticulously classify osteogenic and adipogenic differentiation. Specifically, four notable pre-trained CNN models, VGG 19, Inception V3, ResNet 18, and ResNet 50, were developed and tested for identifying adipogenic and osteogenic differentiated cells based on cell morphology changes. We rigorously evaluated the performance of these four models concerning binary and multi-class classification of differentiated cells at various time intervals, focusing on pivotal metrics such as accuracy, the area under the receiver operating characteristic curve (AUC), sensitivity, precision, and F1-score. Among these four different models, ResNet 50 has proven to be the most effective choice with the highest accuracy (0.9572 for binary, 0.9474 for multi-class) and AUC (0.9958 for binary, 0.9836 for multi-class) in both multi-class and binary classification tasks. Although VGG 19 matched the accuracy of ResNet 50 in both tasks, ResNet 50 consistently outperformed it in terms of AUC, underscoring its superior effectiveness in identifying differentiated cells. Overall, our study demonstrated the capability to use a CNN approach to predict stem cell fate based on morphology changes, which will potentially provide insights for the application of cell-based therapy and advance our understanding of regenerative medicine.

KLF2 regulates stemness of human mesenchymal stem cells by targeting FGFR3

Mesenchymal stem cells (MSCs) are an attractive source of pluripotent cells for regenerative therapy; however, maintaining stemness and self-renewal of MSCs during expansion ex vivo is challenging. For future clinical applications, it is essential to define the roles and signaling pathways that regulate the fate of MSCs. Based on our earlier finding that Krüppel-like factor 2 (KLF2) participates in maintaining stemness in MSCs, we examined further the role of this factor in intrinsic signaling pathways. Using a chromatin immunoprecipitation (ChIP)-sequence assay, we found that the FGFR3 gene is a KLF2 binding site. Knockdown of FGFR3 significantly decreased the levels of key pluripotency factors, enhanced the expression of differentiation-related genes and down-regulated colony formation of human bone marrow MSCs (hBMSCs). Using alizarin red S and oil red O staining, we found that knockdown of FGFR3 inhibited the osteogenic and adipogenic ability of MSCs under conditions of differentiation. The ChIP-qPCR assay confirmed that KLF2 interacts with the promoter regions of FGFR3. Our findings suggest that KLF2 promotes hBMSC stemness by direct regulation of FGFR. Our findings may contribute to enhanced MSC stemness by genetic modification of stemness-related genes.

Innovations in Stem Cell Therapy for Diabetic Wound Healing

Significance: The global burden of diabetic wounds, particularly diabetic foot ulcers, continues to have large economic and social impact throughout the world. Current strategies are not sufficient to overcome this burden of disease. Finding newer, more advanced regenerative cell and tissue-based strategies to reduce morbidity remains paramount. Recent Advances: Recent advances in stem cell therapies are discussed. We also highlight the practical issues of translating these advancing technologies into the clinical setting. Critical Issues: We discuss the use of somatic and induced pluripotent stem cells and the stromal vascular fraction, as well as innovations, including the use of 3D bioprinting of skin. We also explore related issues of using regenerative techniques in clinical practice, including the current regulatory landscape and translatability of in vivo research. Future Directions: Advances in stem cell manipulation showcase the best therapeutic resources available to enhance mechanisms of wound healing such as angiogenesis, cell proliferation, and collagen synthesis; potential methods include changing the scaffold microenvironment, including relative oxygen tension, and the use of gene modification and nanotechnology. Secretome engineering, particularly the use of extracellular vesicles, may be another potential cell-derived therapeutic that may enable use of cell-free translational therapy.

The role of SPARC (secreted protein acidic and rich in cysteine) in the pathogenesis of obesity, type 2 diabetes, and non-alcoholic fatty liver disease

Secreted protein acidic and rich in cysteine (SPARC) is an extracellular matrix glycoprotein with pleiotropic functions, which is expressed in adipose, hepatic, muscular, and pancreatic tissue. Particularly, several studies demonstrated that SPARC is an important player in the context of obesity, diabetes, and fatty liver disease including advanced hepatic fibrosis and hepatocellular carcinoma. Evidence in murine and human samples indicates that SPARC is involved in adipogenesis, cellular metabolism, extracellular matrix modulation, glucose and lipid metabolism, among others. Furthermore, studies in SPARC knockout mouse model showed that SPARC contributes to adipose tissue formation, non-alcoholic fatty liver disease (NAFLD), and diabetes. Hence, SPARC may represent a novel and interesting target protein for future therapeutic interventions or a biomarker of disease progression. This review summarizes the role of SPARC in the pathophysiology of obesity, and extensively revised SPARC functions in physiological and pathological adipose tissue deposition, muscle metabolism, liver, and diabetes-related pathways.

VCAM-1+ hUC-MSCs Exert Considerable Neuroprotection Against Cerebral Infarction in Rats by Suppression of NLRP3-Induced Pyroptosis

Mesenchymal stem/stromal cells (MSCs) are spindle-like heterogeneous cell populations with advantageous bidirectional immunomodulatory and hematopoietic support effects. Vascular cellular adhesion molecule-1 (VCAM-1)+ MSCs have been reported to exhibit immunoregulatory and proangiogenic capacities. Here, we studied the effects of VCAM-1+ human umbilical cord (hUC)-MSCs on neuroprotection against cerebral infarction. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO), and VCAM-1- and VCAM-1+ hUC-MSCs were intravenously injected into the rat 4 h post-MCAO surgery. Thereafter, modified neurological severity scores (mNSS) were determined, and the Morris water maze test, 2,3,5-triphenyltetrazolium chloride (TTC), hematoxylin and eosin (H&E), Nissl, TUNEL staining, and qRT-PCR were conducted. Following induction of oxygen-glucose deprivation/reoxygenation (OGD/R), SH-SY5Y cells were co-cultured with VCAM-1- and VCAM-1+ hUC-MSCs. CCK-8, flow cytometry, ELISA, and western blot analyses were performed in vitro. Compared with VCAM-1- hUC-MSCs, administration of VCAM-1+ hUC-MSCs revealed improved therapeutic efficacy against cerebral infarction in rats, as confirmed by lower mNSS scores and infarct volumes, as well as improved learning and memory capacities. In addition, VCAM-1+ hUC-MSCs exhibited improved efficacy against neurological defects in rats with cerebral infarction, accompanied by inhibition of the NLRP3-mediated inflammatory response. VCAM-1+ hUC-MSC co-culture improved the viability and diminished NLRP3-mediated inflammatory response in OGD/R-treated SH-SY5Y cells. Moreover, NLRP3 overexpression in SH-SY5Y cells prevented the beneficial effects of VCAM-1+ hUC-MSC co-culture. Overall, our findings demonstrated the relevance of VCAM-1+ hUC-MSC-based cytotherapy for preclinical neuroprotection against cerebral infarction.

A robust and standardized method to isolate and expand mesenchymal stromal cells from human umbilical cord

BACKGROUND AIMS

Human umbilical cord-derived mesenchymal stromal cells (hUC-MSCs) are increasingly used in research and therapy. To obtain hUC-MSCs, a diversity of isolation and expansion methods are applied. Here, we report on a robust and standardized method for hUC-MSC isolation and expansion.

METHODS

Using 90 hUC donors, we compared and optimized critical variables during each phase of the multi-step procedure involving UC collection, processing, MSC isolation, expansion and characterization. Furthermore, we assessed the effect of donor-to-donor variability regarding UC morphology and donor attributes on hUC-MSC characteristics.

RESULTS

We demonstrated robustness of our method across 90 UC donors at each step of the procedure. With our method, UCs can be collected up to 6 h after birth, and UC-processing can be initiated up to 48 h after collection without impacting on hUC-MSC characteristics. The removal of blood vessels before explant cultures improved hUC-MSC purity. Expansion in Minimum essential medium α supplemented with human platelet lysate increased reproducibility of the expansion rate and MSC characteristics as compared with Dulbecco's Modified Eagle's Medium supplemented with fetal bovine serum. The isolated hUC-MSCs showed a purity of ∼98.9%, a viability of >97% and a high proliferative capacity. Trilineage differentiation capacity of hUC-MSCs was reduced as compared with bone marrow-derived MSCs. Functional assays indicated that the hUC-MSCs were able to inhibit T-cell proliferation demonstrating their immune-modulatory capacity.

CONCLUSIONS

We present a robust and standardized method to isolate and expand hUC-MSCs, minimizing technical variability and thereby lay a foundation to advance reliability and comparability of results obtained from different donors and different studies.

A Supportive Role of Mesenchymal Stem Cells on Insulin-Producing Langerhans Islets with a Specific Emphasis on The Secretome

Type 1 Diabetes (T1D) is a chronic autoimmune disease characterized by a gradual destruction of insulin-producing β-cells in the endocrine pancreas due to innate and specific immune responses, leading to impaired glucose homeostasis. T1D patients usually require regular insulin injections after meals to maintain normal serum glucose levels. In severe cases, pancreas or Langerhans islet transplantation can assist in reaching a sufficient β-mass to normalize glucose homeostasis. The latter procedure is limited because of low donor availability, high islet loss, and immune rejection. There is still a need to develop new technologies to improve islet survival and implantation and to keep the islets functional. Mesenchymal stem cells (MSCs) are multipotent non-hematopoietic progenitor cells with high plasticity that can support human pancreatic islet function both in vitro and in vivo and islet co-transplantation with MSCs is more effective than islet transplantation alone in attenuating diabetes progression. The beneficial effect of MSCs on islet function is due to a combined effect on angiogenesis, suppression of immune responses, and secretion of growth factors essential for islet survival and function. In this review, various aspects of MSCs related to islet function and diabetes are described.

Preservation of critical quality attributes of mesenchymal stromal cells in 3D bioprinted structures by using natural hydrogel scaffolds

Three dimensional (3D) bioprinting is an emerging technology that enables complex spatial modeling of cell-based tissue engineering products, whose therapeutic potential in regenerative medicine is enormous. However, its success largely depends on the definition of a bioprintable zone, which is specific for each combination of cell-loaded hydrogels (or bioinks) and scaffolds, matching the mechanical and biological characteristics of the target tissue to be repaired. Therefore proper adjustment of the bioink formulation requires a compromise between: (i) the maintenance of cellular critical quality attributes (CQA) within a defined range of specifications to cell component, and (ii) the mechanical characteristics of the printed tissue to biofabricate. Herein, we investigated the advantages of using natural hydrogel-based bioinks to preserve the most relevant CQA in bone tissue regeneration applications, particularly focusing on cell viability and osteogenic potential of multipotent mesenchymal stromal cells (MSCs) displaying tripotency in vitro, and a phenotypic profile of 99.9% CD105+ /CD45,- 10.3% HLA-DR,+ 100.0% CD90,+ and 99.2% CD73+ /CD31- expression. Remarkably, hyaluronic acid, fibrin, and gelatin allowed for optimal recovery of viable cells, while preserving MSC's proliferation capacity and osteogenic potency in vitro. This was achieved by providing a 3D structure with a compression module below 8.8 ± 0.5 kPa, given that higher values resulted in cell loss by mechanical stress. Beyond the biocompatibility of naturally occurring polymers, our results highlight the enhanced protection on CQA exerted by bioinks of natural origin (preferably HA, gelatin, and fibrin) on MSC, bone marrow during the 3D bioprinting process, reducing shear stress and offering structural support for proliferation and osteogenic differentiation.

Bioenergetic profile and redox tone modulate in vitro osteogenesis of human dental pulp stem cells: new perspectives for bone regeneration and repair

BACKGROUND

Redox signaling and energy metabolism are known to be involved in controlling the balance between self-renewal and proliferation/differentiation of stem cells. In this study we investigated metabolic and redox changes occurring during in vitro human dental pulp stem cells (hDPSCs) osteoblastic (OB) differentiation and tested on them the impact of the reactive oxygen species (ROS) signaling.

METHODS

hDPSCs were isolated from dental pulp and subjected to alkaline phosphatase and alizarin red staining, q-RT-PCR, and western blotting analysis of differentiation markers to assess achievement of osteogenic/odontogenic differentiation. Moreover, a combination of metabolic flux analysis and confocal cyto-imaging was used to profile the metabolic phenotype and to evaluate the redox tone of hDPSCs.

RESULTS

In differentiating hDPSCs we observed the down-regulation of the mitochondrial respiratory chain complexes expression since the early phase of the process, confirmed by metabolic flux analysis, and a reduction of the basal intracellular peroxide level in its later phase. In addition, dampened glycolysis was observed, thereby indicating a lower energy-generating phenotype in differentiating hDPSCs. Treatment with the ROS scavenger Trolox, applied in the early-middle phases of the process, markedly delayed OB differentiation of hDPSCs assessed as ALP activity, Runx2 expression, mineralization capacity, expression of stemness and osteoblast marker genes (Nanog, Lin28, Dspp, Ocn) and activation of ERK1/2. In addition, the antioxidant partly prevented the inhibitory effect on cell metabolism observed following osteogenic induction.

CONCLUSIONS

Altogether these results provided evidence that redox signaling, likely mediated by peroxide species, influenced the stepwise osteogenic expansion/differentiation of hDPSCs and contributed to shape its accompanying metabolic phenotype changes thus improving their efficiency in bone regeneration and repair.

Hybrid spheroids containing mesenchymal stem cells promote therapeutic angiogenesis by increasing engraftment of co-transplanted endothelial colony-forming cells in vivo

BACKGROUND

Peripheral artery disease is an ischemic vascular disease caused by the blockage of blood vessels supplying blood to the lower extremities. Mesenchymal stem cells (MSCs) and endothelial colony-forming cells (ECFCs) have been reported to alleviate peripheral artery disease by forming new blood vessels. However, the clinical application of MSCs and ECFCs has been impeded by their poor in vivo engraftment after cell transplantation. To augment in vivo engraftment of transplanted MSCs and ECFCs, we investigated the effects of hybrid cell spheroids, which mimic a tissue-like environment, on the therapeutic efficacy and survival of transplanted cells.

METHODS

The in vivo survival and angiogenic activities of the spheroids or cell suspension composed of MSCs and ECFCs were measured in a murine hindlimb ischemia model and Matrigel plug assay. In the hindlimb ischemia model, the hybrid spheroids showed enhanced therapeutic effects compared with the control groups, such as adherent cultured cells or spheroids containing either MSCs or ECFCs.

RESULTS

Spheroids from MSCs, but not from ECFCs, exhibited prolonged in vivo survival compared with adherent cultured cells, whereas hybrid spheroids composed of MSCs and ECFCs substantially increased the survival of ECFCs. Moreover, single spheroids of either MSCs or ECFCs secreted greater levels of pro-angiogenic factors than adherent cultured cells, and the hybrid spheroids of MSCs and ECFCs promoted the secretion of several pro-angiogenic factors, such as angiopoietin-2 and platelet-derived growth factor.

CONCLUSION

These results suggest that hybrid spheroids containing MSCs can serve as carriers for cell transplantation of ECFCs which have poor in vivo engraftment efficiency.

Aldehyde Dehydrogenase, a Marker of Normal and Malignant Stem Cells, Typifies Mesenchymal Progenitors in Perivascular Niches

Innate mesenchymal stem cells exhibiting multilineage differentiation and tissue (re)generative-or pathogenic-properties reside in perivascular niches. Subsets of these progenitors are committed to either osteo-, adipo-, or fibrogenesis, suggesting the existence of a developmental organization in blood vessel walls. We evaluated herein the activity of aldehyde dehydrogenase, a family of enzymes catalyzing the oxidation of aldehydes into carboxylic acids and a reported biomarker of normal and malignant stem cells, within human adipose tissue perivascular areas. A progression of ALDHLow to ALDHHigh CD34+ cells was identified in the tunica adventitia. Mesenchymal stem cell potential was confined to ALDHHigh cells, as assessed by proliferation and multilineage differentiation in vitro of cells sorted by flow cytometry with a fluorescent ALDH substrate. RNA sequencing confirmed and validated that ALDHHigh cells have a progenitor cell phenotype and provided evidence that the main isoform in this fraction is ALDH1A1, which was confirmed by immunohistochemistry. This demonstrates that ALDH activity, which marks hematopoietic progenitors and stem cells in diverse malignant tumors, also typifies native, blood vessel resident mesenchymal stem cells.

Dynamic Stimulations with Bioengineered Extracellular Matrix-Mimicking Hydrogels for Mechano Cell Reprogramming and Therapy

Cells interact with their surrounding environment through a combination of static and dynamic mechanical signals that vary over stimulus types, intensity, space, and time. Compared to static mechanical signals such as stiffness, porosity, and topography, the current understanding on the effects of dynamic mechanical stimulations on cells remains limited, attributing to a lack of access to devices, the complexity of experimental set-up, and data interpretation. Yet, in the pursuit of emerging translational applications (e.g., cell manufacturing for clinical treatment), it is crucial to understand how cells respond to a variety of dynamic forces that are omnipresent in vivo so that they can be exploited to enhance manufacturing and therapeutic outcomes. With a rising appreciation of the extracellular matrix (ECM) as a key regulator of biofunctions, researchers have bioengineered a suite of ECM-mimicking hydrogels, which can be fine-tuned with spatiotemporal mechanical cues to model complex static and dynamic mechanical profiles. This review first discusses how mechanical stimuli may impact different cellular components and the various mechanobiology pathways involved. Then, how hydrogels can be designed to incorporate static and dynamic mechanical parameters to influence cell behaviors are described. The Scopus database is also used to analyze the relative strength in evidence, ranging from strong to weak, based on number of published literatures, associated citations, and treatment significance. Additionally, the impacts of static and dynamic mechanical stimulations on clinically relevant cell types including mesenchymal stem cells, fibroblasts, and immune cells, are evaluated. The aim is to draw attention to the paucity of studies on the effects of dynamic mechanical stimuli on cells, as well as to highlight the potential of using a cocktail of various types and intensities of mechanical stimulations to influence cell fates (similar to the concept of biochemical cocktail to direct cell fate). It is envisioned that this progress report will inspire more exciting translational development of mechanoresponsive hydrogels for biomedical applications.

The covert symphony: cellular and molecular accomplices in breast cancer metastasis

Breast cancer has emerged as the most commonly diagnosed cancer and primary cause of cancer-related deaths among women worldwide. Although significant progress has been made in targeting the primary tumor, the effectiveness of systemic treatments to prevent metastasis remains limited. Metastatic disease continues to be the predominant factor leading to fatality in the majority of breast cancer patients. The existence of a prolonged latency period between initial treatment and eventual recurrence in certain patients indicates that tumors can both adapt to and interact with the systemic environment of the host, facilitating and sustaining the progression of the disease. In order to identify potential therapeutic interventions for metastasis, it will be crucial to gain a comprehensive framework surrounding the mechanisms driving the growth, survival, and spread of tumor cells, as well as their interaction with supporting cells of the microenvironment. This review aims to consolidate recent discoveries concerning critical aspects of breast cancer metastasis, encompassing the intricate network of cells, molecules, and physical factors that contribute to metastasis, as well as the molecular mechanisms governing cancer dormancy.

Side population cells derived from hUCMSCs and hPMSCs could inhibit the malignant behaviors of Tn+ colorectal cancer cells from modifying their O-glycosylation status

BACKGROUND

Cosmc (C1GalT1C1) mutation could cause aberrant O-glycosylation and result in expression of Tn antigen on the surface of tumor cells (Tn⁺ cells), which is associated with the metastasis and prognosis of cancer progression. Mesenchymal stem cells (MSCs) could participate in immunoregulation, tissue damage repair, and tumor inhibition and be seen as an ideal candidate for tumor therapy due to their inherent capacity to migrate to tumor sites. However, their therapeutic effectiveness in different tumors is inconsistent and still controversial. Of note, emerging data reveal that side population (SP) cells have a stronger multilineage developmental potential than main population cells and can function as stem/progenitor cells. The effect of SP cells derived from MSCs on the biological behaviors and the O-glycosylation status of tumor cells remains unclear.

METHODS

SP cells were isolated from human umbilical cord MSCs (hUCMSCs) and human placenta MSCs (hPMSCs). Tn⁺ cells (LS174T-Tn⁺ and HT-29-Tn⁺ cells) and matching Tn^- cells (LS174T-Tn^- and HT-29-Tn^- cells) were isolated from human colorectal cancer cell (CRC) lines LS174T and HT-29 by immune magnetic beads. The proliferation, migration, apoptosis, Tn antigen expression, and O-glycome in Tn⁺ and Tn^- CRC cells before and after co-cultured with SP-MSCs were detected using real-time cell Analysis (RTCA), flow cytometry (FCM), and cellular O-glycome reporter/amplification (CORA), respectively. Cosmc protein and O-glycosyltransferase (T-synthase and C3GnT) activity in CRC cells were, respectively, assessed using western blotting and fluorescence method.

RESULTS

Both SP cells derived from hUCMSCs and hPMSCs could inhibit proliferation and migration, promote apoptosis of CRC cells, significantly reduce Tn antigen expression on Tn⁺ CRC cells, generate new core 1-, 2-, and 3-derived O-glycans, increase T-synthase and C3GnT activity, and elevate the levels of Cosmc and T-synthase protein.

CONCLUSION

SP-hUCMSCs and SP-hPMSCs could inhibit proliferation and migration and promote apoptosis of Tn⁺ CRC cells via increasing O-glycosyltransferase activity to modify O-glycosylation status, which further adds a new dimension to the treatment of CRC.

Three-Dimensional Spheroid Culture of Human Mesenchymal Stem Cells: Offering Therapeutic Advantages and In Vitro Glimpses of the In Vivo State

As invaluable as the standard 2-dimensional (2D) monolayer in vitro cell culture system has been, there is increasing evidence that 3-dimensional (3D) non-adherent conditions are more relevant to the in vivo condition. While one of the criteria for human mesenchymal stem cells (MSCs) has been in vitro plastic adherence, such 2D culture conditions are not representative of in vivo cell-cell and cell-extracellular matrix (ECM) interactions, which may be especially important for this progenitor/stem cell of skeletal and connective tissues. The 3D spheroid, a multicellular aggregate formed under non-adherent 3D in vitro conditions, may be particularly suited as an in vitro method to better understand MSC physiological processes, since expression of ECM and other adhesion proteins are upregulated in such a cell culture system. First used in embryonic stem cell in vitro culture to recapitulate in vivo developmental processes, 3D spheroid culture has grown in popularity as an in vitro method to mimic the 3-dimensionality of the native niche for MSCs within tissues/organs. In this review, we discuss the relevance of the 3D spheroid culture for understanding MSC biology, summarize the biological outcomes reported in the literature based on such this culture condition, as well as contemplate limitations and future considerations in this rapidly evolving and exciting area.