Stem Cell Regenerative Medicine Research Articles

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

Stem cells are undifferentiated cells that possess the potential for self-renewal with the capacity to differentiate into multiple lineages. In humans, their limited numbers pose a challenge in fulfilling the necessary demands for the regeneration and repair of damaged tissues or organs. Studies suggested that mesenchymal stem cells (MSCs), necessary for repair and regeneration via transplantation, require doses ranging from 10 to 400 million cells. Furthermore, the limited expansion of MSCs restricts their therapeutic application. To optimize a novel protocol to achieve qualitative and quantitative expansion of MSCs to reach the targeted number of cells for cellular transplantation and minimize the limitations in stem cell therapy protocols. Human umbilical cord (hUC) tissue derived MSCs were obtained and re-cultured. These cultured cells were subjected to the following evaluation procedures: Immunophenotyping, immunocytochemical staining, trilineage differentiation, population doubling time and number, gene expression markers for proliferation, cell cycle progression, senescence-associated β-galactosidase assay, human telomerase reverse transcriptase (hTERT) expression, mycoplasma, cytomegalovirus and endotoxin detection. Analysis of pluripotent gene markers Oct4, Sox2, and Nanog in recultured hUC-MSC revealed no significant differences. The immunophenotypic markers CD90, CD73, CD105, CD44, vimentin, CD29, Stro-1, and Lin28 were positively expressed by these recultured expanded MSCs, and were found negative for CD34, CD11b, CD19, CD45, and HLA-DR. The recultured hUC-MSC population continued to expand through passage 15. Proliferative gene expression of Pax6, BMP2, and TGFb1 showed no significant variation between recultured hUC-MSC groups. Nevertheless, a significant increase (P < 0.001) in the mitotic phase of the cell cycle was observed in recultured hUC-MSCs. Cellular senescence markers (hTERT expression and β-galactosidase activity) did not show any negative effect on recultured hUC-MSCs. Additionally, quality control assessments consistently confirmed the absence of mycoplasma, cytomegalovirus, and endotoxin contamination. This study proposes the development of a novel protocol for efficiently expanding stem cell population. This would address the growing demand for larger stem cell doses needed for cellular transplantation and will significantly improve the feasibility of stem cell based therapies.

Exploring stem cell frontiers: definitions, challenges, and perspectives for regenerative medicine.

Each year, the European Summer School on Stem Cell Biology and Regenerative Medicine (SCSS) attracts early-career researchers and actively practicing clinicians who specialise in stem cell and regenerative biology. The 16th edition of this influential course took place from 12th to 19th September 2023 on the charming Greek island of Spetses. Focusing on important concepts and recent advances in stem cells, the distinguished faculty included experts spanning the spectrum from fundamental research to clinical trials to market-approved therapies. Alongside an academically intensive programme that bridges the various contexts of stem cell research, delegates were encouraged to critically address relevant questions in stem cell biology and medicine, including broader societal implications. Here, we present a comprehensive overview and key highlights from the SCSS 2023.

Dynamic Roles of Signaling Pathways in Maintaining Pluripotency of Mouse and Human Embryonic Stem Cells.

Culturing of mouse and human embryonic stem cells (ESCs) in vitro was a major breakthrough in the field of stem cell biology. These models gained popularity very soon mainly due to their pluripotency. Evidently, the ESCs of mouse and human origin share typical phenotypic responses due to their pluripotent nature, such as self-renewal capacity and potency. The conserved network of core transcription factors regulates these responses. However, significantly different signaling pathways and upstream transcriptional networks regulate expression and activity of these core pluripotency factors in ESCs of both the species. In fact, ample evidence shows that a pathway, which maintains pluripotency in mouse ESCs, promotes differentiation in human ESCs. In this review, we discuss the role of canonical signaling pathways implicated in regulation of pluripotency and differentiation particularly in mouse and human ESCs. We believe that understanding these distinct and at times-opposite mechanisms-is critical for the progress in the field of stem cell biology and regenerative medicine.

The biological characteristics of chicken embryo mesenchymal stem cells isolated from chorioallantoic membrane.

Mesenchymal stem cells (MSCs) derived from fetal membranes (FMs) have the potential to exhibit immunosuppression, improve blood flow, and increase capillary density during transplantation. In the field of medicine, opening up new avenues for disease treatment. Chicken embryo chorioallantoic membrane (CAM), as an important component of avian species FM structure, has become a stable tissue engineering material in vivo angiogenesis, drug delivery, and toxicology studies. Although it has been confirmed that chorionic mesenchymal stem cells (Ch-MSCs) can be isolated from the outer chorionic layer of FM, little is known about the biological characteristics of MSCs derived from chorionic mesodermal matrix of chicken embryos. Therefore, we evaluated the characteristics of MSCs isolated from chorionic tissues of chicken embryos, including cell proliferation ability, stem cell surface antigen, genetic stability, and in vitro differentiation potential. Ch-MSCs exhibited a broad spindle shaped appearance and could stably maintain diploid karyotype proliferation to passage 15 in vitro. Spindle cells were positive for multifunctional markers of MSCs (CD29, CD44, CD73, CD90, CD105, CD166, OCT4, and NANOG), while hematopoietic cell surface marker CD34, panleukocyte marker CD45, and epithelial cell marker CK19 were negative. In addition, chicken Ch-MSC was induced to differentiate into four types of mesodermal cells in vitro, including osteoblasts, chondrocytes, adipocytes, and myoblasts. Therefore, the differentiation potential of chicken Ch-MSC in vitro may have great potential in tissue engineering. In conclusion, chicken Ch-MSCs may be an excellent model cell for stem cell regenerative medicine and chorionic tissue engineering.

The genome of the colonial hydroid Hydractinia reveals that their stem cells use a toolkit of evolutionarily shared genes with all animals.

Hydractinia is a colonial marine hydroid that shows remarkable biological properties, including the capacity to regenerate its entire body throughout its lifetime, a process made possible by its adult migratory stem cells, known as i-cells. Here, we provide an in-depth characterization of the genomic structure and gene content of two Hydractinia species, Hydractinia symbiolongicarpus and Hydractinia echinata, placing them in a comparative evolutionary framework with other cnidarian genomes. We also generated and annotated a single-cell transcriptomic atlas for adult male H. symbiolongicarpus and identified cell-type markers for all major cell types, including key i-cell markers. Orthology analyses based on the markers revealed that Hydractinia's i-cells are highly enriched in genes that are widely shared amongst animals, a striking finding given that Hydractinia has a higher proportion of phylum-specific genes than any of the other 41 animals in our orthology analysis. These results indicate that Hydractinia's stem cells and early progenitor cells may use a toolkit shared with all animals, making it a promising model organism for future exploration of stem cell biology and regenerative medicine. The genomic and transcriptomic resources for Hydractinia presented here will enable further studies of their regenerative capacity, colonial morphology, and ability to distinguish self from nonself.

Industry updates from the field of stem cell research and regenerative medicine in January 2024.

Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from nonacademic institutions in January 2024.

Adipose Tissue and Bone Marrow-Derived Mesenchymal Stem Cells are not Really the Same: Investigating the Differences in Their Immunomodulatory, Migratory, and Adhesive Profile.

Mesenchymal stem cells (MSCs) are the most widely used stem cells in regenerative medicine. They can be isolated from multiple sources, most commonly bone marrow and adipose tissue. MSCs derived from different sources show similar molecular and biological characteristics, but there is ongoing debate regarding the best source of MSCs and the potential biological differences between MSCs from different origins. Bone marrow derived-MSCs (BM-MSCs) and adipose tissue-derived MSCs (AD-MSCs) share many molecular and immunomodulatory properties. In this study, we compared the levels of major immunomodulatory, adhesive, and migratory factors in human BM-MSCs and AD-MSCs under normal conditions, which will help determine the suitability and specificity of each type for certain therapeutic applications. WST1 assay and fluorescent assay SUC-LLVY-AMC were used to measure MSC proliferation and 26S proteasome activity, respectively. Western blotting, ELISA Assays, and bright field live imaging were also used. AD-MSCs and BM-MSCs exhibited similar morphology and proliferation rate. A significantly higher 26S proteasome activity was detected in AD-MSCs than in BM-MSCs. Levels of ICAM-1, integrin α5 and integrin α6 were significantly higher in AD-MSCs compared to BM-MSCs, while no significant difference in CXCR4 levels was observed. Expression of IDO and factor H was significantly higher in AD-MSCs, while CTLA-4 and IL-10 levels were higher in BM-MSCs. This indicates that AD-MSCs and BM-MSCs have different immunomodulatory and adhesion profiles. MSCs isolated from different sources may show differences in their biological and immunomodulatory properties, suggesting a potential suitability of certain MSCs type for specific conditions. Also, combination of different MSCs types could help optimize therapeutic outcomes.

Expression of a mutant CD47 protects against phagocytosis without inducing cell death or inhibiting angiogenesis

CD47 is a ligand of SIRPα, an inhibitory receptor expressed by macrophages, dendritic cells, and natural killer (NK) cells, and, therefore, transgenic overexpression of CD47 is considered an effective approach to inhibiting transplant rejection. However, the detrimental effect of CD47 signaling is overlooked when exploring this approach. Here, we construct a mutant CD47 by replacing the transmembrane and intracellular domains with a membrane anchor (CD47-IgV). In both human and mouse cells, CD47-IgV is efficiently expressed on the cellsurface and protects against phagocytosis invitro and invivo but does not induce cell death or inhibit angiogenesis. Furthermore, hematopoietic stem cells expressing transgenic CD47-IgV show no detectable alterations in engraftment or differentiation. This study provides a potentially effective means of achieving transgenic CD47 expression that may help to produce gene-edited pigs for xenotransplantation and hypoimmunogenic pluripotent stem cells for regenerative medicine.

Molecular mechanism underlying miR-204-5p regulation of adipose-derived stem cells differentiation into cells from three germ layers

The limited differentiation ability of adipose-derived stem cells (ADSCs) limits their application in stem cell therapy and regenerative medicine. Here, we explore the molecular mechanism by which miR-204-5p regulates ADSCs differentiation into cells derived from the three germ layers (i.e., adipocytes, neurocytes, and hepatocytes). Although miR-204-5p overexpression inhibited ADSCs differentiation into adipocytes, neurocyte and hepatocyte differentiation were promoted. Mechanistically, miR-204-5p inhibited the expression of PPARG by regulating the AMPK signaling pathway, thereby inhibiting ADSCs differentiation into adipocytes. Further, miR-204-5p regulated JAG1/NOTCH3 axis for the inhibition of differentiation into adipocytes and promotion of differentiation into neurocytes. miR-204-5p might also promote ADSCs differentiation into hepatocytes by upregulating E2F8. The findings of this study provide novel insights into the regulatory mechanisms underlying early embryonic development and will help to facilitate the application of ADSCs in stem cell therapy and regenerative medicine.

Industry updates from the field of stem cell research and regenerative medicine in December 2023.

Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in December 2023.

Industry updates from the field of stem cell research and regenerative medicine in October 2023.

Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in October 2023.

Industry updates from the field of stem cell research and regenerative medicine in November 2023.

Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in November 2023.

Applications of Plant-Made Fibroblast Growth Factor for Human Pluripotent Stem Cells.

Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) hold great potential in regenerative medicine. These cells can be expanded indefinitely in theory and are able to differentiate into different types of cells for cell therapies, drug screening, and basic biology studies. The reliable and effective propagation of hESCs and hiPSCs is important for their downstream applications. Basic fibroblast growth factor (bFGF) is critical to hESCs and hiPSCs for maintaining their pluripotency. Plant-produced growth factors are safe to use without potential contamination of infectious viruses and are less expensive to produce. In this study, we used rice cell-made basic fibroblast growth factor (RbFGF) to propagate hESCs and hiPSCs for at least eight passages. Both hESCs and hiPSCs cultured with RbFGF not only maintained the morphology but also the specific expression (OCT4, SSEA4, SOX2, and TRA-1-60) of PSCs, similar to those cultured with the commercial Escherichia coli-produced bFGF. Furthermore, both gene chip-based PluriTest and TaqMan hPSC Scorecard pluripotency analysis demonstrated the pluripotent expression profile of the hESCs cultured with RbFGF. In vitro trilineage assays further showed that these hESCs and hiPSCs cultured on RbFGF were capable of giving rise to cell derivatives of ectoderm, mesoderm, and endoderm, further demonstrating their pluripotency. Finally, chromosome stability was also maintained in hESCs cultured with RbFGF as demonstrated by normal karyotypes. This study suggests broad applications for plant-made growth factors in stem cell culture and regenerative medicine.

An engineered ligand-responsive Csy4 endoribonuclease controls transgene expression from Sendai virus vectors

BackgroundViral vectors are attractive gene delivery vehicles because of their broad tropism, high transduction efficiency, and durable expression. With no risk of integration into the host genome, the vectors developed from RNA viruses such as Sendai virus (SeV) are especially promising. However, RNA-based vectors have limited applicability because they lack a convenient method to control transgene expression by an external inducer.ResultsWe engineered a Csy4 switch in Sendai virus-based vectors by combining Csy4 endoribonuclease with mutant FKBP12 (DD: destabilizing domain) that becomes stabilized when a small chemical Shield1 is supplied. In this Shield1-responsive Csy4 (SrC) switch, Shield1 increases Csy4 fused with DD (DD-Csy4), which then cleaves and downregulates the transgene mRNA containing the Csy4 recognition sequence (Csy4RS). Moreover, when Csy4RS is inserted in the viral L gene, the SrC switch suppresses replication and transcription of the SeV vector in infected cells in a Shield1-dependent manner, thus enabling complete elimination of the vector from the cells. By temporally controlling BRN4 expression, a BRN4-expressing SeV vector equipped with the SrC switch achieves efficient, stepwise differentiation of embryonic stem cells into neural stem cells, and then into astrocytes.ConclusionSeV-based vectors with the SrC switch should find wide applications in stem cell research, regenerative medicine, and gene therapy, especially when precise control of reprogramming factor expression is desirable.

Unleashing the Power of Undifferentiated Induced Pluripotent Stem Cell Bioprinting: Current Progress and Future Prospects.

Induced pluripotent stem cell (iPSC) technology has revolutionized various fields, including stem cell research, disease modeling, and regenerative medicine. The evolution of iPSC-based models has transitioned from conventional two-dimensional systems to more physiologically relevant three-dimensional (3D) models such as spheroids and organoids. Nonetheless, there still remain challenges including limitations in creating complex 3D tissue geometry and structures, the emergence of necrotic core in existing 3D models, and limited scalability and reproducibility. 3D bioprinting has emerged as a revolutionary technology that can facilitate the development of complex 3D tissues and organs with high scalability and reproducibility. This innovative approach has the potential to effectively bridge the gap between conventional iPSC models and complex 3D tissues in vivo. This review focuses on current trends and advancements in the bioprinting of iPSCs. Specifically, it covers the fundamental concepts and techniques of bioprinting and bioink design, reviews recent progress in iPSC bioprinting research with a specific focus on bioprinting undifferentiated iPSCs, and concludes by discussing existing limitations and future prospects.

Industry updates from the field of stem cell research and regenerative medicine in September 2023.

Latest developments in the field of stem cell research and regenerative medicine compiled from publicly available information and press releases from non-academic institutions in September 2023.

Update on the Clinical Applications of Mesenchymal Stem Cells

Mesenchymal stem cells are heterogenous adult multipotent stromal cells that can be isolated from various sources including bone marrow, peripheral blood, umbilical cord blood, dental pulp, and adipose tissue. They have certain regenerative, anti-inflammatory, immunomodulatory, immunosuppressive, antimicrobial, and other properties that enable them to have several therapeutic and clinical applications including treatment of various autoimmune disorders; role in hematopoietic stem cell transplantation and regenerative medicine; treatment of skin, pulmonary and cardiovascular disorders; treatment of neurological and eye diseases; as well as treatment of various infections and their complications. Different factors including donor age, biological source, route of administration, and signaling pathways have an impact on the functions and consequently the clinical applications of mesenchymal stromal cells. The products of mesenchymal stem cells such as extracellular vesicles and exosomes reproduce the biological effects and most of the therapeutic actions of the parent stem cells. Genetic engineering and the use of specific mesenchymal stromal cell products have improved their clinical efficacy and decreased their adverse effects. However, despite the recent progress in the use of mesenchymal stem cells, the clinical application of these cells in the treatment of several diseases still faces real challenges that need to be resolved. The current status of mesenchymal stem cells and the controversies related to their clinical utilization in various disease conditions will be thoroughly discussed in this review.

Mesenchymal stromal cells, metabolism, and mitochondrial transfer in bone marrow normal and malignant hematopoiesis.

Hematopoietic stem cell (HSC) transplantation-based treatments are in different phases of clinical development, ranging from current therapies to a promise in the repair and regeneration of diseased tissues and organs. Mesenchymal stromal/stem cells (MSCs), which are fibroblast-like heterogeneous progenitors with multilineage differentiation (osteogenic, chondrogenic, and adipogenic) and self-renewal potential, and exist in the bone marrow (BM), adipose, and synovium, among other tissues, represent one of the most widely used sources of stem cells in regenerative medicine. MSCs derived from bone marrow (BM-MSCs) exhibit a variety of traits, including the potential to drive HSC fate and anti-inflammatory and immunosuppressive capabilities via paracrine activities and interactions with the innate and adaptive immune systems. The role of BM-MSC-derived adipocytes is more controversial and may act as positive or negative regulators of benign or malignant hematopoiesis based on their anatomical location and functional crosstalk with surrounding cells in the BM microenvironment. This review highlights the most recent clinical and pre-clinical findings on how BM-MSCs interact with the surrounding HSCs, progenitors, and immune cells, and address some recent insights on the mechanisms that mediate MSCs and adipocyte metabolic control through a metabolic crosstalk between BM microenvironment cells and intercellular mitochondrial transfer in normal and malignant hematopoiesis.

HLA-based banking of induced pluripotent stem cells in Saudi Arabia

BackgroundHuman iPSCs' derivation and use in clinical studies are transforming medicine. Yet, there is a high cost and long waiting time associated with autologous iPS-based cellular therapy, and the genetic engineering of hypo-immunogenic iPS cell lines is hampered with numerous hurdles. Therefore, it is increasingly interesting to create cell stocks based on HLA haplotype distribution in a given population. This study aimed to assess the potential of HLA-based iPS banking for the Saudi population.MethodsIn this study, we interrogated the HLA database of the Saudi Stem Cell Donor Registry (SSCDR), containing high-resolution HLA genotype data from 64,315 registered Saudi donors at the time of analysis. This database was considered to be a representative sample of the Saudi population. The most frequent HLA haplotypes in the Saudi population were determined, and an in-house developed iterative algorithm was used to identify their HLA matching percentages in the SSCDR database and cumulative coverage. Subsequently, to develop a clinically relevant protocol for iPSCs generation, and to illustrate the applicability of the concept of HLA-based banking for cell therapy purposes, the first HLA-based iPS cell line in Saudi Arabia was generated. Clinically relevant methods were employed to generate the two iPS clones from a homozygous donor for the most prevalent HLA haplotype in the Saudi population. The generated lines were then assessed for pluripotency markers, and their ability to differentiate into all three germ layers, beating cardiomyocytes, and neural progenitors was examined. Additionally, the genetic stability of the HLA-iPS cell lines was verified by comparing the mutational burden in the clones and the original blood sample, using whole-genome sequencing. The standards set by the American College of Medical Genetics and Genomics (ACMG) were used to determine the clinical significance of identified variants.ResultsThe analysis revealed that the establishment of only 13 iPSC lines would match 30% of the Saudi population, 39 lines would attain 50% coverage, and 596 lines would be necessary for over 90% coverage. The proof-of-concept HLA-iPSCs, which cover 6.1% of the Saudi population, successfully demonstrated pluripotency and the ability to differentiate into various cell types including beating cardiomyocytes and neuronal progenitors. The comprehensive genetic analysis corroborated that all identified variants in the derived iPSCs were inherently present in the original donor sample and were classified as benign according to the standards set by the ACMG.ConclusionsOur study sets a road map for introducing iPS-based cell therapy in the Kingdom of Saudi Arabia. It underscores the pragmatic approach of HLA-based iPSC banking which circumvents the limitations of autologous iPS-based cellular therapies. The successful generation and validation of iPSC lines based on the most prevalent HLA haplotype in the Saudi population signify a promising step toward broadening the accessibility and applicability of stem cell therapies and regenerative medicine in Saudi Arabia.

Stem cell mutations, associated cancer risk, and consequences for regenerative medicine.

Mutation accumulation in stem cells has been associated with cancer risk. However, the presence of numerous mutant clones in healthy tissues has raised the question of what limits cancer initiation. Here, we review recent developments in characterizing mutation accumulation in healthy tissues and compare mutation rates in stem cells during development and adult life with corresponding cancer risk. A certain level of mutagenesis within the stem cell pool might be beneficial to limit the size of malignant clones through competition. This knowledge impacts our understanding of carcinogenesis with potential consequences for the use of stem cells in regenerative medicine.