Regenerative Medicine Applications Research Articles

Preserving Stem Cells for Potential Use in Future Reparative Medicine

With its enormous potential for regenerative medicine and therapeutic applications, stem cell preservation represents a major breakthrough in biomedical science. Stem cells are gathered, processed, and stored under carefully monitored circumstances in order to preserve their viability for potential use in the future. Because they may differentiate into a variety of cell types, stem cells—especially those derived from sources like umbilical cord blood—are essential for both therapeutic and research uses. An essential function of cord blood banking is to offer a plentiful supply of immune system cells that may be stored for potential future therapeutic applications. Immunological deficits, osteoarthritis, Parkinson's disease, and heart failure are just a few of the conditions for which stem cell treatments have shown promise. Notwithstanding the promise, there remain obstacles such immunological rejection and the need for more research to fully comprehend the development and functionality of stem cells. It is essential for the general public to be informed about stem cell treatments and cord blood banking in order for expectant parents to make well-informed decisions. Future advancements in the subject depend heavily on resolving ethical issues and enhancing the effectiveness of stem cell-based therapies. To fully realise the promise of stem cell preservation in conventional medicine, more research, creativity, and international cooperation are required.

Humanized In Vivo Bone Tissue Engineering: In Vitro Preculture Conditions Control the Structural, Cellular, and Matrix Composition of Humanized Bone Organs.

Bone tissue engineering (BTE) has long sought to elucidate the key factors controlling human/humanized bone formation for regenerative medicine and disease modeling applications, yet with no definitive answers due to the high number and co-dependency of parameters. This study aims to clarify the relative impacts of in vitro biomimetic 'preculture composition' and 'preculture duration' before in vivo implantation as key criteria for the optimization of BTE design. These parameters are directly related to in vitro osteogenic differentiation (OD) and mineralization and are being investigated across different osteoprogenitor-loaded biomaterials, specifically fibrous calcium phosphate-polycaprolactone (CaP-mPCL) scaffolds and gelatin methacryloyl (GelMA) hydrogels. The results show that OD and mineralization levels prior to implantation, enhanced by a mineralization medium supplement to the osteogenic medium (OM), significantly improve ectopic BTE outcomes, regardless of the biomaterial type. Specifically, preculture conditions are pivotal in achieving more faithful mimicry of human bone structure, cellular and extracellular matrix composition and organization, and provide control over bone marrow composition. This work emphasizes the potential of using biomimetic culture compositions, specifically the addition of a mineralization medium as a cost-effective and straightforward approach to enhance BTE outcomes, facilitating rapid development of bone models with superior quality and resemblance to native bone.

Recent Updates on Diverse Nanoparticles and Nanostructures in Therapeutic and Diagnostic Applications with Special Focus on Smart Protein Nanoparticles: A Review.

Nanomedicine enables advanced therapeutics, diagnostics, and predictive analysis, enhancing treatment outcomes and patient care. The choices and development of high-quality organic nanoparticles with relatively lower toxicity are important for achieving advanced medical goals. Among organic molecules, proteins have been prospected as smart candidates to revolutionize nanomedicine due to their inherent fascinating features. The advent of protein nanoarchitectures, which explore the biomolecular corona, offers new insights into their efficient tissue penetration and therapeutic potential. This review examines various animal- and plant-based protein nanoparticles, highlighting their source, activity, products, and unique biomedical applications in regenerative medicine, targeted therapies, gene and drug delivery, antimicrobial activity, bioimaging, immunological adjuvants, etc. It provides an extensive discussion on recent applications of protein nanoparticles across diverse biomedical fields as well as the evolving landscape of other nanoproducts and nanodevices for sensitive medical procedures. Furthermore, this review introduces different preparation technologies of protein nanoparticles, emphasizing how their design and construction significantly influence loading capacity, stability, and targeting effects. Additionally, we delve into the construction of different user-friendly multifunctional modular bioarchitectures by the assembly of protein nanoparticles (PNPs), marking a significant breakthrough in therapies. This review also considers the challenges of synthetic nanomaterials and the emergence of natural alternatives, which provides insights into protein nanoparticle research.

Application of hydrogel-loaded dental stem cells in the field of tissue regeneration.

Mesenchymal stem cells (MSCs) are highly favored in clinical trials due to their unique characteristics, which have isolated from various human tissues. Derived from dental tissues, dental stem cells (DSCs) are particularly notable for their applications in tissue repair and regenerative medicine, attributed to their readily available sources, absence of ethical controversies, and minimal immunogenicity. Hydrogel-loaded stem cell therapy is widespread across a variety of injuries and diseases, and has good repair capabilities for both soft and hard tissues. This review comprehensively summarizes the regenerative and differentiation potential of various DSCs encapsulated in hydrogels across different tissues. In addition, the existing problems and future direction are also addressed. The application of hydrogel-DSCs composite has gained substantial progress in the field of tissue regeneration and need in-depth study in the future.

Potential Use of Organoids in Regenerative Medicine.

In vitro cell culture is crucial for studying human diseases and development. Compared to traditional monolayer cultures, 3D culturing with organoids offers significant advantages by more accurately replicating natural tissues' structural and functional features. This advancement enhances disease modeling, drug testing, and regenerative medicine applications. Organoids, derived from stem cells, mimic tissue physiology in a more relevant manner. Despite their promise, the clinical use of regenerative medicine currently needs to be improved by reproducibility, scalability, and maturation issues. This article overviews recent organoid research, focusing on their types, sources, 3D culturing methods, and applications in regenerative medicine. A literature review of "organoid" and "regenerative medicine" in PubMed/MEDLINE highlighted relevant studies published over the past decade, emphasizing human-sourced organoids and their regenerative benefits, as well as the availability of free full-text articles. The review uses descriptive data, including tables and text, to illustrate the challenges and potential of organoids in regenerative medicine. The transition from 2D to 3D models, particularly organoids, has significantly advanced in vitro research. This review covers a decade of progress in various organoid types-such as liver, cholangiocyte, intestinal, pancreatic, cardiac, brain, thymus, and mammary organoids-and their 3D culture methods and applications. It addresses critical issues of maturity, scalability, and reproducibility and underscores the need for standardization and improved production techniques to facilitate broader clinical applications in regenerative medicine. Successful therapy requires increased scalability and standardization. Organoids have enormous potential in biological research, notwithstanding obstacles.

Advancements in 3D Skin Bioprinting: Processes, Bioinks, Applications and Sensor Integration

Abstract This comprehensive review explores the multifaceted landscape of skin bioprinting, revolutionizing dermatological research. The applications of skin bioprinting utilizing techniques like extrusion-, droplet-, laser- and light-based methods, with specialized bioinks for skin biofabrication have been critically reviewed along with the intricate aspects of bioprinting hair follicles, sweat glands, and achieving skin pigmentation. Challenges remain with the need for vascularization, safety concerns, and the integration of automated processes for effective clinical translation. The review further investigates the incorporation of biosensor technologies, emphasizing their role in monitoring and enhancing the wound healing process. While highlighting the remarkable progress in the field, critical limitations and concerns are critically examined to provide a balanced perspective. This synthesis aims to guide scientists, engineers, and healthcare providers, fostering a deeper understanding of the current state, challenges, and future directions in skin bioprinting for transformative applications in tissue engineering and regenerative medicine.

From banked human cord blood to induced pluripotent stem cells: New opportunities and promise in induced pluripotent stem cell banking (Review).

Umbilical cord blood (CB) is a valuable source of haematopoietic stem/progenitor cells (HSCs) and is known for the therapeutic use of these cells in treating blood disorders. However, challenges such as a high running cost and the increasing availability of treatment alternatives have made the effort to sustain CB banks difficult. This prompts the need to revisit the current CB banking initiatives to retain the relevance in this ever‑changing era parallel to the fast‑pacing development of cell‑based therapeutic technology. Cellular reprogramming has shown to have successfully converted adult somatic cells into human induced pluripotent stem cells (hiPSCs), which promise wider applications in regenerative medicine, personalized treatment and tissue engineering. CB is the youngest, primitive adult cell source that has not been affected by any prior, acquired disorders. Hence, using CB as a source of candidate cells for generating hiPSCs may be a new opportunity for banking, albeit with challenges. The present review summarizes the rise and fall of CB usage and banking for clinical therapy, the considerations in reprogramming CB into hiPSCs, the safety concerns regarding the use of hiPSC‑derived cells in clinical transplantation and the prospect of using CB‑derived hiPSCs.

3D Bioprinting of Thick Adipose Tissues with Integrated Vascular Hierarchies

AbstractEngineering functional, thick tissues with integrated vascular architectures is crucial for advancing regenerative medicine. This study applied a novel 3D bioprinting strategy to construct thick adipose tissues featuring complex, hierarchical vascular networks. Mature adipocytes and endothelial cells are encapsulated within a collagen matrix, with structural integrity and vascular functionality ensured through a combination of bioinks. An innovative approach is utilized to establish millimetric vascular channels that connect to microvascular networks, forming a fully perfusable, hierarchical vasculature throughout the 3D bioprinted tissue. The structural stability and endothelial functionality of the vascularized constructs are assessed under continuous flow. In‐vitro analyses confirmed the integrity of the vascular networks and demonstrated the functional characteristics of the printed mature adipose cells. Direct anastomosis of the bioprinted tissue to a rat femoral artery resulted in effective vascular integration and tissue viability, as evidenced by efficient blood perfusion and significant host vascular ingrowth within the implanted tissues. The findings highlighted the potential of the presented bioprinting technique in the development of fully functional, vascularized adipose tissues suitable for surgical reconstruction and regenerative medicine applications.

Setting a Successful Sorting for Extracellular Vesicle Isolation.

Extracellular vesicles (EVs) released by mesenchymal stromal cells (MSCs) contain a set of microRNAs with regenerative and anti-inflammatory roles. Therefore, purified MSC-EVs are envisioned as a next-generation therapeutic option for a wide array of diseases. In this protocol, we report the strategy for successfully sorting EVs from the supernatant of adipose-derived MSCs (ASCs), often used in orthopedics regenerative medicine applications. First, we described the sample preparation, focusing on EV isolation and labeling steps with carboxyfluorescein succinimidyl ester (CFSE) for fluorescence detection; subsequently, we detailed the sorting process, which constitutes the main part of the protocol. In addition to the rules defined by MISEV 2023 and MIFlowCyt EV guidelines, we applied specific experimental conditions concerning nozzle size, frequency, and sheath pressure. Morphological parameters are established using beads of diameters selected to cover the theoretical range of EV size. After ASC-EVs sorting, we performed a purity check of the sorted fraction by re-analyzing it with the sorter and verifying the EV size distribution with the nanoparticle tracking analysis technique. Due to the increasing importance of EVs, having a pure population to study and characterize is becoming crucial. Here, we demonstrate a winner strategy to set up sorting to achieve this goal.

Alternative Method for Obtaining Human-Induced Pluripotent Stem Cell Lines and Three-Dimensional Growth: A Simplified, Passage-Free Approach that Minimizes Labor.

Induced pluripotent stem cells (iPSCs) hold significant promise for numerous applications in regenerative medicine, disease modeling, and drug discovery. However, the conventional workflow for iPSC generation, with cells grown under two-dimensional conditions, presents several challenges, including the need for specialized scientific skills such as morphologically assessing and picking colonies and removing differentiated cells during the establishment phase. Furthermore, maintaining established iPSCs in three-dimensional culture systems, while offering scalability, necessitates an enzymatic dissociation step for their further growth in a complex and time-consuming protocol. In this study, we introduce a novel approach to address these challenges by reprogramming somatic cells grown under three-dimensional conditions as spheres using a bioreactor, thereby eliminating the need for two-dimensional culture and colony picking. The iPSCs generated in this study were maintained under three-dimensional conditions simply by transferring spheres to the next bioreactor, without the need for an enzymatic dissociation step. This streamlined method simplifies the workflow, reduces technical variability and labor, and paves the way for future advancements in iPSC research and its wider applications. Key features • Establishment of induced pluripotent stem cells in a three-dimensional environment. • Maintenance and cryopreservation of iPSCs without the need for a dissociation step.

Therapeutic Potential of MSC-Derived Extracellular Vesicles Carrying miRNAs for Modulating Autophagy and Cellular Degeneration in Intervertebral Disc Degeneration.

This research utilized bioinformatics and in vitro modeling to assess the effects of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) containing specific microRNAs (miRNAs) on the autophagy and degeneration of nucleus pulposus (NP) cells in intervertebral disc degeneration (IDD). To determine the therapeutic potential of MSC-EVs loaded with miRNAs in modulating pathological changes in IDD. IDD is characterized by changes in gene expression that contribute to cell degeneration and reduced disc integrity. MSC-EVs are known for their role in cellular communication and potentially reversing these degenerative processes. Key differentially expressed miRNAs and mRNAs in MSC-EVs were identified using bioinformatics analysis. Three miRNAs (miR-486-5p, miR-3648, miR-1827) typically down-regulated in IDD were selected for further study. The bone marrow-derived MSC-EVs used in this study were cultured in a 2D environment. These MSC-EVs were isolated with the purpose of delivering the selected miRNAs to IDD NP cells in vitro, targeting specifically the upregulated genes (SMAD2, ESR1, MAVS, MMP14) associated with autophagy and degeneration. MSC-EV treatment led to significant downregulation of target genes, enhanced cellular proliferation, and decreased apoptosis and autophagy. Overexpression of these target genes produced the opposite effects, confirming the miRNAs' regulatory roles. MSC-EVs carrying specific miRNAs can effectively modulate gene expression, reduce degenerative processes, and promote cellular proliferation in IDD, indicating a promising therapeutic strategy for treating IDD and potentially other degenerative diseases. Further investigations are warranted to explore MSC-EV applications in regenerative medicine.

Engineering synthetic agonists for targeted activation of Notch signaling.

Notch signaling regulates cell fate decisions and has context-dependent tumorigenic or tumor suppressor functions. Although there are several classes of Notch inhibitors, the mechanical force requirement for Notch receptor activation has hindered attempts to generate soluble agonists. To address this problem, we engineered synthetic Notch agonist (SNAG) proteins by tethering affinity-matured Notch ligands to antibodies or cytokines that internalize their targets. This bispecific format enables SNAGs to "pull" on mechanosensitive Notch receptors, triggering their activation in the presence of a desired biomarker. We successfully developed SNAGs targeting six independent surface markers, including the tumor antigens PDL1, CD19, and HER2, and the immunostimulatory receptor CD40. SNAGs targeting CD40 increase expansion of central memory γδ T cells from peripheral blood, highlighting their potential to improve the phenotype and yield of low-abundance T cell subsets. These insights have broad implications for the pharmacological activation of mechanoreceptors and will expand our ability to modulate Notch signaling in biotechnology.

Sericin coats of silk fibres, a degumming waste or future material?

Silk is a fibrous biopolymer with a recorded history in the textile industries for centuries. This fibre is constituted of two different proteins: fibroin and sericin, of which the latter accounting for approximately 20-30% of the silk mass. Silk sericin (SSER) was previously considered as a waste by-product in silk fibroin extraction. SSER has recently garnered significant scientific interest due to its extensive biological and pharmacological properties. These include antioxidant effects, biocompatibility, low immunogenicity, controlled biodegradability, and the ability to induce cell proliferation. This review covers the previous studies about various aspects of this emerging material, namely, its general morphology, specific structure, molecular weight, features of different layers, and gene sequences. The impact of different extraction methods and the application of extracted SSER based on molecular weight are discussed. Additionally, the characteristic functional groups in the amino acids of sericin facilitate its applications in regenerative medicine, wound healing, drug delivery, textile, environment, and energy, in various forms like hydrogels, films, scaffolds, and conduits. SSER-based materials offer great potentials for multi-functional applications in the upcoming decades, showcasing adaptability for various functional uses and promising future technological advancements.

Proteomic analysis of the human amniotic mesenchymal stromal cell secretome by integrated approaches via filter-aided sample preparation

The immunomodulatory, anti-inflammatory and regenerative properties of the human amniotic mesenchymal stromal cells (hAMSCs) secretome are acknowledged but the understanding of the specific bioactive components remains incomplete. To address these limitations, the present investigation aimed to profile the proteins and peptides content of the hAMSC secretome through sample pretreatment and fractionation on 10 kDa molecular cut-off FASP (Filter Aided Sample Preparation) device and LC-MS analysis. The filter retained protein fraction underwent trypsin digestion, while the unretained was collected unchanged for intact small proteins and peptides analysis. This combined approach (C-FASP) collects in a single step two complementary fractions, advantageously saving sample volume and time of analysis. The bottom-up analysis of the C-FASP proteins fraction >10 kDa confirmed our previous findings, establishing a set of proteins consistently characterizing the hAMSC secretome. The analysis of the fraction <10 kDa, never been investigated to our knowledge, identified peptide fragments of thymosin beta 4 and beta 10, collagen alpha 1 chains I and III, alpha-enolase, and glyceraldehyde-3-phosphate dehydrogenase, involved in wound healing, anti-inflammatory response, tissue repair and regeneration, key biological activities of the secretome. C-FASP provided a comprehensive molecular profile of the hAMSC secretome offering new insights for enhanced therapeutic applications in regenerative medicine. SignificanceIn this investigation we originally present the comprehensive proteomic investigation of the human amniotic mesenchymal stromal cell secretome by combining the analysis of the proteome and of the peptidome following sample pretreatment and fractionation by Filter Aided Sample Preparation (FASP) with 10 kDa molecular cut-off in coupling with LC-MS analysis. The proteome fraction retained by FASP filter was analyzed after enzymatic digestion, while the unretained fraction, below 10 kDa molecular mass, was analyzed unchanged in its intact form. This dual approach provides novel insights, previously unexplored, into the molecular components potentially responsible for the immunomodulatory and anti-inflammatory properties of the hAMSC secretome. These findings could significantly enhance the therapeutic potential of hAMSCs in regenerative medicine.

Preparation of recombinant type I collagen (PF-I-80) and its functional characterization and biomedical applications in wound healing

This study evaluates the potential applications of recombinant PF-I-80 protein in regenerative medicine and the treatment of inflammatory diseases, focusing on its effects on cell migration, differentiation, and anti-inflammatory properties. Various in vitro assays were conducted, including scratch assays, Transwell experiments, RT-PCR and Western Blot to analyze gene and protein expression related to differentiation and inflammation, and immunofluorescence staining to observe cellular changes. The results indicated that PF-I-80 significantly promoted cell migration, highlighting its potential in tissue repair and regeneration. It also enhanced cell differentiation, demonstrating its applicability in tissue repair, and showed significant anti-inflammatory effects by reducing the expression of pro-inflammatory cytokines. In animal models, PF-I-80 notably reduced levels of inflammatory factors IL-1β and TNF-α, shortened the inflammatory phase, and accelerated wound healing. Additionally, PF-I-80 increased FGF-2 levels, which promoted the proliferation of endothelial and fibroblast cells and enhanced collagen synthesis. These in vitro and in vivo findings position PF-I-80 as a promising biomaterial for applications in regenerative medicine and inflammatory disease treatment.

Cryogenic 3D Printing of GelMA/Graphene Bioinks: Improved Mechanical Strength and Structural Properties for Tissue Engineering.

Tissue engineering aims to recreate natural cellular environments to facilitate tissue regeneration. Gelatin methacrylate (GelMA) is widely utilized for its biocompatibility, ability to support cell adhesion and proliferation, and adjustable mechanical characteristics. This study developed a GelMA and graphene bioink platform at concentrations of 1, 1.5, and 2 mg/mL to enhance scaffold properties for tissue engineering applications. Graphene was incorporated into GelMA matrices to improve mechanical strength and electrical conductivity of the bioinks. The compressive strength and thermal stability of the resulting GelMA/graphene scaffolds were assessed through DSC analysis and mechanical testing. Cytotoxicity assays were conducted to determine cell survival rates. Cryoprinting at -30°C was employed to preserve scaffold structure and function. The chorioallantoic membrane (CAM) assay was used to evaluate biocompatibility and angiogenic potential. The integration of graphene significantly amplified the compressive strength and thermal stability of GelMA scaffolds. Cytotoxicity assays indicated robust cell survival rates of 90%, confirming the biocompatibility of the developed materials. Cryoprinting effectively preserved scaffold integrity and functionality. The CAM assay validated the biocompatibility and angiogenic potential, demonstrating substantial vascularization upon scaffold implantation onto chick embryo CAM. Integrating graphene into GelMA hydrogels, coupled with low-temperature 3D printing, represents a potent strategy for enhancing scaffold fabrication. The resultant GelMA/graphene scaffolds exhibit superior mechanical properties, biocompatibility, and pro-vascularization capabilities, making them highly suitable for diverse tissue engineering and regenerative medicine applications.

Directed Differentiation of Adipose-Derived Stem Cells Using Imprinted Cell-Like Topographies as a Growth Factor-Free Approach.

The influence of surface topography on stem cell behavior and differentiation has garnered significant attention in regenerative medicine and tissue engineering. The cell-imprinting method has been introduced as a promising approach to mimic the geometry and topography of cells. The cell-imprinted substrates are designed to replicate the topographies and dimensions of target cells, enabling tailored interactions that promote the differentiation of stem cells towards desired specialized cell types. In fact, by replicating the size and shape of cells, biomimetic substrates provide physical cues that profoundly impact stem cell differentiation. These cues play a pivotal role in directing cell morphology, cytoskeletal organization, and gene expression, ultimately influencing lineage commitment. The biomimetic substrates' ability to emulate the native cellular microenvironment supports the creation of platforms capable of steering stem cell fate with high precision. This review discusses the role of mechanical factors that impact stem cell fate. It also provides an overview of the design and fabrication principles of cell-imprinted substrates. Furthermore, the paper delves into the use of cell-imprinted polydimethylsiloxane (PDMS) substrates to direct adipose-derived stem cells (ADSCs) differentiation into a variety of specialized cells for tissue engineering and regenerative medicine applications. Additionally, the review discusses the limitations of cell-imprinted PDMS substrates and highlights the efforts made to overcome these limitations.

Remote-Controlled Gene Delivery in Coaxial 3D-Bioprinted Constructs using Ultrasound-Responsive Bioinks

IntroductionCoaxial 3D bioprinting has advanced the formation of tissue constructs that recapitulate key architectures and biophysical parameters for in-vitro disease modeling and tissue-engineered therapies. Controlling gene expression within these structures is critical for modulating cell signaling and probing cell behavior. However, current transfection strategies are limited in spatiotemporal control because dense 3D scaffolds hinder diffusion of traditional vectors. To address this, we developed a coaxial extrusion 3D bioprinting technique using ultrasound-responsive gene delivery bioinks. These bioink materials incorporate echogenic microbubble gene delivery particles that upon ultrasound exposure can sonoporate cells within the construct, facilitating controllable transfection.MethodsPhospholipid-coated gas-core microbubbles were electrostatically coupled to reporter transgene plasmid payloads and incorporated into cell-laden alginate bioinks at varying particle concentrations. These bioinks were loaded into the coaxial nozzle core for extrusion bioprinting with CaCl2 crosslinker in the outer sheath. Resulting bioprints were exposed to 2.25 MHz focused ultrasound and evaluated for microbubble activation and subsequent DNA delivery and transgene expression.ResultsCoaxial printing parameters were established that preserved the stability of ultrasound-responsive gene delivery particles for at least 48 h in bioprinted alginate filaments while maintaining high cell viability. Successful sonoporation of embedded cells resulted in DNA delivery and robust ultrasound-controlled transgene expression. The number of transfected cells was modulated by varying the number of focused ultrasound pulses applied. The size region over which DNA was delivered was modulated by varying the concentration of microbubbles in the printed filaments.ConclusionsOur results present a successful coaxial 3D bioprinting technique designed to facilitate ultrasound-controlled gene delivery. This platform enables remote, spatiotemporally-defined genetic manipulation in coaxially bioprinted tissue constructs with important applications for disease modeling and regenerative medicine.

Characterization of neuronal differentiation in human adipose-derived stromal cells: morphological, molecular, and ultrastructural insights

ObjectiveAdipose-derived stromal cells (ADSCs) have shown promise as a potential source of neural differentiation. In this study, we investigated the morphological, molecular and ultrastructural features of ADSCs during neuronal differentiation. MethodsADSCs were induced in vitro and their differentiation was examined at different time points. Immunocytochemical staining was performed to detect the expression of neuron-specific markers NSE and MAP-2. Immunofluorescence double labeling and Western blot detected the co-expression of presynaptic markers (CaMKII, SynCAM1, SYN) and postsynaptic markers (PSD-95, Synapsin I). Scanning electron microscopy (SEM) was performed to detect the synaptic structural features of differentiated neurons. ResultsADSCs showed diverse morphological features during differentiation, gradually acquiring a neuron-like spindle shape and organized arrangement. The expression of neuron-specific markers and synaptic markers peaked at 5 h of induction. Scanning electron microscopy showed polygonal protrusions of ADSC-derived neurons, and transmission electron microscopy showed characteristic ultrastructures such as nidus, synaptic vesicle-like structures, and tight junctions. ConclusionOur findings suggest that ADSCs differentiated for 5 h have neuronal features, including morphological, molecular, and ultrastructural resemblance to neurons, as well as the formation of synaptic structures. These insights contribute to a better understanding of ADSC-based neuronal differentiation and pave the way for future applications in regenerative medicine and neurodegenerative diseases.

Dissecting dormancy and quiescence in hematopoietic stem cells

Quiescence is a fundamental state of adult hematopoietic stem cells (HSCs) characterized by their residence in the G0 phase of the cell cycle. Despite being quiescent, HSCs retain their capacities for self-renewal and multipotency, enabling them to produce all blood lineages. Recent discoveries have shown that HSCs can dive into an even deeper state of quiescence with a very low division rate in steady-state conditions, known as dormancy. Dormant HSCs (dHSCs) have the most superior stem cell properties among HSCs, placing them at the top of the hematopoietic hierarchy. In this review, we argue that quiescence and dormancy are not synonyms in the context of HSCs. Specifically, dHSCs constitute a unique reserve pool of HSCs, mobilized only under stress conditions to protect the HSC compartment throughout life. While HSC quiescence is well-studied, the molecular features of HSC dormancy remain less well-defined. We will discuss the available methods for dHSC isolation and summarize the latest findings on the roles of niche factors, transcription factors, chromatin regulators, and cell cycle-related proteins in maintaining HSC dormancy. Additionally, we will explore whether insights from the quiescent HSC research can be applied to dHSCs. Lastly, we will assess the therapeutic potential of utilizing or targeting dHSCs to improve stem cell transplantation outcomes and treat hematological diseases, opening new avenues for research and clinical applications in regenerative medicine and oncology.