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AICP is a crucial process that maintaining tissue homeostasis and regeneration. In the past, cell death was perceived merely as a means to discard cells without functional consequences. However, during regeneration, effector caspases orchestrate apoptosis, releasing signals that activate stem cells, thereby compensating for tissue loss across various animal models. Despite significant progress, the activation of Wnt3a by caspase-3 remains a focal point of research gaps in AICP mechanisms, spanning from lower to higher regenerative animals. This inquiry into the molecular intricacies of caspase-3-induced Wnt3a activation contributes to a deeper understanding of the links between regeneration and cancer mechanisms. Our report provides current updates on AICP pathways, delineating research gaps and highlighting the potential for future investigations aimed at enhancing our comprehension of this intricate process. [ABSTRACT FROM AUTHOR]

Context: The MEIS proteins, originally described as the "helper groups" of HOX proteins, are now becoming recognized as significant and incredibly diverse controllers of cellular behavior. The MEIS agents can incorporate a variety of epigenetic modulators into chromatin to aid in embryonic growth or tissue homeostasis by adult stem cells. The MEIS gene's expression, binding, stability, post-translational protein modification, and controlled intracellular availability are all fully regulated, and they all react to external stimuli. Objectives: We explored the diverse roles of MEIS proteins in cellular behavior and epigenetic regulation and investigated the potential of MEIS proteins as diagnostic and therapeutic biomarkers in cancers. Results: The MEIS proteins can be diagnostic and therapeutic biomarkers for cancer. The MEIS-PBX heterotrimeric is involved in neurogenesis processes, and the formation of the MEIS2 heterodimer with PAX6 and DLX2 can proliferate periplomerular dopaminergic neurons in the olfactory bulb. The estrogen receptor in breast cancer upregulates MEIS1 and FOXP3. The estrogen receptor pathway's cancer-related genes can express themselves more strongly when MEIS1-FOXP3 interacts with a positive feedback mechanism. Because MEIS1 expression is decreased in clear renal cell carcinoma (ccRCC) cell lines, MEIS1 may function as a tumor suppressor in the development of ccRCC. Conclusions: MEIS1 is recognized as one of the main contributors to the development of leukemias. The MEIS proteins influence the c-MYC signaling pathway, cell proliferation, and invasion of PC by contributing to its development. [ABSTRACT FROM AUTHOR]

Background: Human adipose-derived stromal/stem cells (hASCs) play important roles in regenerative medicine and numerous inflammatory diseases. However, their cellular heterogeneity limits the effectiveness of treatment. Understanding the distinct subtypes of hASCs and their phenotypic implications will enable the selection of appropriate subpopulations for targeted approaches in regenerative medicine or inflammatory diseases. Methods: hASC subtypes expressing dipeptidyl peptidase-4 (DPP4) were identified via fluorescence-activated cell sorting (FACS) analysis. DPP4 expression was knocked down in DPP4+ hASCs via DPP4 siRNA. The capacity for proliferation, hepatocyte differentiation, inflammatory factor secretion and T-cell functionality regulation of hASCs from DPP4−, DPP4+, and control siRNA-treated DPP4+ hASCs and DPP4 siRNA-treated DPP4+ hASCs were assessed. Results: DPP4+ hASCs and control siRNA-treated DPP4+ hASCs presented a lower proliferative capacity but greater hepatocyte differentiation capacity than DPP4− hASCs and DPP4 siRNA-treated DPP4+ hASCs. Both DPP4+ hASCs and DPP4− hASCs secreted high levels of vascular endothelial growth factor-A (VEGF-A), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6 (IL-6), whereas the levels of other factors, including matrix metalloproteinase (MMP)-1, eotaxin-3, fractalkine (FKN, CX3CL1), growth-related oncogene-alpha (GRO-alpha, CXCL1), monokine induced by interferon-gamma (MIG), macrophage inflammatory protein (MIP)-1beta, and macrophage colony-stimulating factor (M-CSF), were significantly greater in the supernatants of DPP4+ hASCs than in those of DPP4− hASCs. Exposure to hASC subtypes and their conditioned media triggered changes in the secreted cytokine profiles of T cells from healthy donors. The percentage of functional T cells that secreted factors such as MIP-1beta and IL-8 increased when these cells were cocultured with DPP4+ hASCs. The percentage of polyfunctional CD8+ T cells that secreted multiple factors, such as IL-17A, tumour necrosis factor alpha (TNF-α) and TNF-β, decreased when these cells were cocultured with supernatants derived from DPP4+ hASCs. Conclusions: DPP4 may regulate proliferation, hepatocyte differentiation, inflammatory cytokine secretion and T-cell functionality of hASCs. These data provide a key foundation for understanding the important role of hASC subpopulations in the regulation of T cells, which may be helpful for future immune activation studies and allow them to be customized for clinical application. [ABSTRACT FROM AUTHOR]

Objective. Currently, the summaries of research on periodontal ligament stem cells (PDLSCs) are mainly reviews, and the systematic evaluation of all relevant studies is lacking. The aim of our study was to reveal the research status and developmental trends of PDLSCs using bibliometric analyses. Methods. Publications on PDLSC from 2004 to 2023 in the PubMed database were searched and then screened according to certain inclusion and exclusion criteria. Two researchers browsed the included papers and recorded information such as the research type and research model. The VOSviewer software was used to analyze the distribution of authors, journals, and institutions. The contents and directions of PDLSC research were summarized by analyzing high‐frequency keywords. The CiteSpace software was used to monitor burst words, determine hot factors, and indicate developmental trends. Results. During the past two decades, the number of studies on PDLSCs increased. China published the most related papers. The primary type of article was basic research. Among core journals, the Journal of Periodontal Research had the highest number of publications. The Fourth Military Medical University (China) was leading in the number of articles on PDLSCs. Research topics mainly included mechanism of periodontal diseases, tissue engineering and regeneration, biological characteristics of PDLSCs, and comparison with other stem cells. Infectious inflammation and mechanical stimulation were important pathological conditions and research topics. Conclusion. The research of PDLSCs is still in a rapid development stage. Our study provides new insights into the current research status and future trend in this field. [ABSTRACT FROM AUTHOR]

Background: At present, fat transplantation is widely used in the plastic surgery industry, but the long-term preservation rate of transplanted fat decreases because of complications such as oil cysts due to the inability in macrophages to metabolize absorption. In cell-assisted lipotransfer technology, adipose-derived stem cells (ASCs) can influence the inflammatory response of grafts through the immunoregulation in macrophages, and the lipid metabolism in macrophages plays an important role in this process. Therefore, we hypothesized ASCs could improve the retention rate of fat grafts by regulating the progress of lipid metabolism in macrophages. Methods: We established fat transplantation and ASC-assisted fat transplantation model in C57BL/6 mice in vivo, and bone marrow-derived macrophages cocultured with apoptotic adipocytes were treated with or without ASCs in vitro. Graft retention, tissue structure, fibrosis, macrophage phenotype transformation, lipid deposition, mitochondrial morphology, oxygen consumption rate (OCR), fatty acid β-oxidation (FAO) level, and ATP production were assessed. Additionally, fat transplantation and ASC-assisted fat transplantation model was treated with etomoxir which inhibits mitochondrial FAO. Macrophages pretreated with etomoxir were co-cultured with apoptotic adipocytes and treated with or without ASCs. The method aboved was used for detection and verification. Results: In vivo, ASC-assisted fat transplantation improved macrophage mitochondrial expression and FAO level, promoted the early transformation of M2 macrophages, reduced the long-term lipid deposition of macrophages, and improved the retention rate of fat grafts. In vitro, ASCs up-regulated the level of mitochondrial FAO, OCR and ATP production in macrophages, reduced lipid deposition of macrophages and promoted M2 macrophages polarization by paracine function. The ability of ASCs in group pretreated with etomoxir to reduce the foaming of macrophages, promote the transformation to M2 macrophages, and improve the retention rate of fat transplantation was weakened. Conclusions: ASCs increased the retention rate of transplanted fat by upregulating mitochondrial FAO to promote M2 polaration in macrophages. In addition, ASCs up-regulate mitochondrial FAO by paracrine effect to reduce foam cells formation and promote M2 transformation in macrophages in vitro. [ABSTRACT FROM AUTHOR]

Background: Human epithelium-derived stem cells and induced pluripotent stem cells (hiPSCs) possess the capability to support tooth formation and differentiate into functional enamel-secreting ameloblasts, making them promising epithelial-component substitutes for future human tooth regeneration. However, current tissue recombination approaches are not only technically challenging, requiring precise induction procedures and sophisticated microsurgery, but also exhibit low success rates in achieving tooth formation and ameloblastic differentiation. Methods: Suspended human keratinocyte stem cells (hKSCs) or cells from three hiPSC lines were directly mixed with dissociated embryonic mouse dental mesenchymal cells (mDMCs) that possess odontogenic potential in different proportions and reaggregated them to construct bioengineered tooth germs. The success rates of tooth formation and ameloblastic differentiation were confirmed after subrenal culture. The sorting capability, sequential development, and ameloblastic differentiation of stem cells were examined via GFP tracing, RT-PCR, and histological analysis, respectively. Results: Our reaggregation approach achieved an impressive success rate of more than 90% in tooth formation and 100% in ameloblastic differentiation when the chimeric tooth germs contained 1%~10% hKSCs or 5% hiPSCs. In addition, we observed that hiPSCs, upon exposure to mDMCs, initially transformed into epidermal cells, as indicated by KRT14 and CD29 expression, before progressing into dental epithelial cells, as indicated by SP6 and SHH expression. We also found that epithelial-derived hiPSCs, when reaggregated with mDMCs, were more favorable for tooth formation than their mesenchymal-derived counterparts. Conclusions: This study establishes a simplified yet highly effective cell-cell reaggregation strategy for inducing stem cells to support tooth formation and differentiate into functional ameloblasts, paving the way for novel approaches for the development of stem cell-based tooth organoids and bioengineered tooth germs in vitro. [ABSTRACT FROM AUTHOR]

Myocardial infarction (MI) is a serious complication of coronary artery disease. This condition is common worldwide and has a profound impact on patients' lives and quality of life. Despite significant advances in the treatment of heart disease in modern medicine, the efficient treatment of MI still faces a number of challenges. Problems such as scar formation and loss of myocardial function after a heart attack still limit patients' recovery. Therefore, the search for a new therapeutic tool that can promote repair and regeneration of myocardial tissue has become crucial. In this context, mesenchymal stromal cells (MSCs) have attracted much attention as a potential therapeutic tool. MSCs are a class of adult stem cells with multidirectional differentiation potential, derived from bone marrow, fat, placenta and other tissues, and possessing properties such as self-renewal and immunomodulation. The application of MSCs may provide a new direction for the treatment of MI. These stem cells have the potential to differentiate into cardiomyocytes and vascular endothelial cells in damaged tissue and to repair and protect myocardial tissue through anti-inflammatory, anti-fibrotic and pro-neovascularization mechanisms. However, the clinical results of MSCs transplantation for the treatment of MI are less satisfactory due to the limitations of the native function of MSCs. Genetic modification has overcome problems such as the low survival rate of transplanted MSCs in vivo and enhanced their functions of promoting neovascularization and differentiation into cardiomyocytes, paving the way for them to become an effective tool for repair therapy after MI. In previous studies, MSCs have shown some therapeutic potential in experimental animals and preliminary clinical trials. This review aims to provide readers with a comprehensive and in-depth understanding to promote the wider application of engineering MSCs in the field of MI therapy, offering new hope for recovery and improved survival of cardiac patients. [ABSTRACT FROM AUTHOR]

Background: The transplantation of periodontal ligament stem cells (PDLSCs) has been shown to enhance periodontal regeneration in animal models and clinical trials. However, it is not known whether PDLSCs are antibacterial and whether this affects oral microbiota and periodontal regeneration. Methods: We isolated human PDLSCs from periodontal ligament of extracted teeth. Rats' periodontal fenestration defects were prepared, and treated with PDLSC injections (Cell group), using saline injections (Saline group) as the control. The oral microbiota was explored by 16 S rDNA sequencing and compared with that before surgery (PRE group). The antibacterial property of PDLSCs and its underlying mechanism were tested in vitro. Results: Microbiome analyses reveal a decreased biodiversity, a changed community structure, and downregulated community functions of the oral microbiome in the Saline group. PDLSCs injections enhance periodontal regeneration, reverse the decrease in diversity, and increase the abundance of non-pathogenic bacterial Bifidobacterium sp. and Lactobacillus sp., making the oral microbiome similar to that of the PRE group. In vitro, PDLSCs inhibit the growth of Staphylococcus aureus, Escherichia coli, and Fusobacterium nucleatum. The main mechanism of action is postulated to involve production of the cationic antimicrobial peptide LL-37. Conclusions: Our findings reveal that PDLSC injections enhance periodontal regeneration and regulate the oral microbiome to foster an oral cavity microenvironment conducive to symbiotic microbiota associated with health. [ABSTRACT FROM AUTHOR]

Background: Chronic radiation dermatitis (CRD) is a late consequence of radiation with high incidence in patients receiving radiotherapy. Conventional therapies often yield unsatisfactory results. Therefore, this study aimed to explore the therapeutic potential and mechanism of adipose-derived stem cells (ADSCs) for CRD, paving the way for novel regenerative therapies in clinical practice. Methods: Clinical CRD skin biopsies were analyzed to character the pathological changes of CRD skin and guided the animal modeling scheme. Subsequently, an in vivo analysisusing mouse CRD models was conducted to explore their effects of ADSCs on CRD, monitoring therapeutic impact for up to 8 weeks. Transcriptome sequencing and histologic sections analysis were performed to explore the potential therapeutic mechanism of ADSCs. Following observing extensive apoptosis of transplanted ADSCs, the therapeutic effect of ADSCs were compared with those of apoptosis-inhibited ADSCs. Multiphoton imaging and analysis of collagen morphologic features were employed to explain how translated ADSCs promote collagen remodeling at the microscopic level based on the contrast of morphology of collagen fibers. Results: Following injection into CRD-afflicted skin, ADSCs therapy effectively mitigated symptoms of CRD, including acanthosis of the epidermis, fibrosis, and irregular collagen deposition, consistent with the possible therapeutic mechanism suggested by transcriptome sequencing. Notably, in vivo tracking revealed a significant reduction in ADSCs number due to extensive apoptosis. Inhibiting apoptosis in ADSCs partially tempered their therapeutic effects. Mechanically, analysis of collagen morphologic features indicated that translated ADSCs might promote dermal extracellular matrix remodeling through enlarging, lengthening, crimping, and evening collagen, counteracting the atrophy and rupture caused by irradiation. Conclusions: This study demonstrated that ADSCs underwent substantial apoptosis upon local skin transplantation, and paradoxically, this apoptosis is essential for their efficacy in promoting the regeneration of late radiation-impaired skin. Mechanically, transplanted ADSCs could promote the remodeling and rearrangement of radiation-damaged dermal collagen matrix. [ABSTRACT FROM AUTHOR]

Background: The induced membrane technique (IMT) is a two-step procedure used for reconstructing segmental bone defects in the limbs. The osteogenic mechanism after bone grafting using IMT remains unclear, and efforts to modify the original techniques are limited to the investigative phase. Therefore, reviewing existing knowledge and identifying hotspots and new trends in IMT is critical. Methods: We retrieved reviews and articles associated with IMT published between 2004 and 2023 from the Web of Science Core Collection (WoSCC). The keywords included induced membrane technique, guided bone regeneration, bone defect reconstruction, bone graft, stem cells, Masquelet technique, management of bone defects, and scaffold. HistCite, VOSviewer, CiteSpace, and R-bibliometrics were used for scientometric analysis. Results: A total of 1019 publications from 374 academic journals with 33,995 co-cited references by 2,331 institutions from 65 countries or regions were included. China (n = 235) and the United States (n = 215) were the most productive countries, with Shanghai Jiao Tong University producing the most number of publications (n = 18). Journal Injury [co-citations = 1774; impact factor (IF) 2022 = 2.5] published the most manuscripts, while Masquelet AC and Giannoudis PV published literature with a significant influence on IMT, showing more co-citations (n = 727; n = 355). Two preface hotspots of IMT focused on investigating the microscopic mechanism (such as the membrane supporting graft-to-bone union and the role of inflammatory cells) and developing new techniques to improve IMT (such as bone tissue engineering and new drugs). Conclusion: This study comprehensively reviewed the literature about IMT published in the last 20 years using qualitative and quantitative methods, providing valuable information for researchers investigating IMT. [ABSTRACT FROM AUTHOR]

Background: Apoptosis, a form of programmed cell death, is critical for the development and homeostasis of the immune system. Chimeric antigen receptor T (CAR-T) cell therapy, approved for hematologic cancers, retains several limitations and challenges associated with ex vivo manipulation, including CAR T-cell susceptibility to apoptosis. Therefore, strategies to improve T-cell survival and persistence are required. Mesenchymal stem/stromal cells (MSCs) exhibit immunoregulatory and tissue-restoring potential. We have previously shown that the transfer of umbilical cord MSC (UC-MSC)-derived mitochondrial (MitoT) prompts the genetic reprogramming of CD3+ T cells towards a Treg cell lineage. The potency of T cells plays an important role in effective immunotherapy, underscoring the need for improving their metabolic fitness. In the present work, we evaluate the effect of MitoT on apoptotis of native T lymphocytes and engineered CAR-T cells. Methods: We used a cell-free approach using artificial MitoT (Mitoception) of UC-MSC derived MT to peripheral blood mononuclear cells (PBMCs) followed by RNA-seq analysis of CD3+ MitoTpos and MitoTneg sorted cells. Target cell apoptosis was induced with Staurosporine (STS), and cell viability was evaluated with Annexin V/7AAD and TUNEL assays. Changes in apoptotic regulators were assessed by flow cytometry, western blot, and qRT-PCR. The effect of MitoT on 19BBz CAR T-cell apoptosis in response to electroporation with a non-viral transposon-based vector was assessed with Annexin V/7AAD. Results: Gene expression related to apoptosis, cell death and/or responses to different stimuli was modified in CD3+ T cells after Mitoception. CD3+MitoTpos cells were resistant to STS-induced apoptosis compared to MitoTneg cells, showing a decreased percentage in apoptotic T cells as well as in TUNEL+ cells. Additionally, MitoT prevented the STS-induced collapse of the mitochondrial membrane potential (MMP) levels, decreased caspase-3 cleavage, increased BCL2 transcript levels and BCL-2-related BARD1 expression in FACS-sorted CD3+ T cells. Furthermore, UC-MSC-derived MitoT reduced both early and late apoptosis in CAR-T cells following electroporation, and exhibited an increasing trend in cytotoxic activity levels. Conclusions: Artificial MitoT prevents STS-induced apoptosis of human CD3+ T cells by interfering with the caspase pathway. Furthermore, we observed that MitoT confers protection to apoptosis induced by electroporation in MitoTpos CAR T-engineered cells, potentially improving their metabolic fitness and resistance to environmental stress. These results widen the physiological perspective of organelle-based therapies in immune conditions while offering potential avenues to enhance CAR-T treatment outcomes where their viability is compromised. [ABSTRACT FROM AUTHOR]

The transition from fetal primordial germ cells (PGCs) to spermatogonia (SPG) is critical for male germ cell development; however, the detailed transcriptomic dynamics and regulation underlying this transition remain poorly understood. Here by interrogating the comprehensive transcriptome atlas dataset of mouse male germ cells and gonadal cells development, we elucidated the regulatory networks underlying this transition. Our single‐cell transcriptome analysis revealed that the transition from PGCs to SPG was characterized by global hypertranscription. A total of 315 highly active regulators were identified to be potentially involved in this transition, among which a non‐transcription factor (TF) regulator TAGLN2 was validated to be essential for spermatogonial stem cells (SSCs) maintenance and differentiation. Metabolism profiling analysis also revealed dynamic changes in metabolism‐related gene expression during PGC to SPG transition. Furthermore, we uncovered that intricate cell–cell communication exerted potential functions in the regulation of hypertranscription in germ cells by collaborating with stage‐specific active regulators. Collectively, our work extends the understanding of molecular mechanisms underlying male germ cell development, offering insights into the recapitulation of germ cell generation in vitro. [ABSTRACT FROM AUTHOR]

Glioblastoma (GBM), a primary brain tumor, exhibits remarkable invasiveness and is characterized by its intricate location, infiltrative behavior, the presence of both the blood–brain barrier (BBB) and the blood–brain tumor barrier (BBTB), phenotypic diversity, an immunosuppressive microenvironment with limited development yet rich vascularity, as well as the resistant nature of glioblastoma stem cells (GSCs) towards traditional chemotherapy and radiotherapy. These formidable factors present substantial obstacles in the quest for effective GBM treatments. Following extensive research spanning three decades, the hepatocellular receptor A2 (EphA2) receptor tyrosine kinase has emerged as a promising molecular target with translational potential in the realm of cancer therapy. Numerous compounds aimed at targeting EphA2 have undergone rigorous evaluation and clinical investigation. This article provides a comprehensive account of the distinctive roles played by canonical and non-canonical EphA2 signaling in various contexts, while also exploring the involvement of the EphA2-ephrin A1 signaling axis in GBM pathogenesis. Additionally, the review offers an overview of completed clinical trials targeting EphA2 for GBM treatment, shedding light on both the prospects and challenges associated with EphA2-directed interventions in the domain of cancer therapeutics. [ABSTRACT FROM AUTHOR]

Articular cartilage is a tissue with relatively poor self‐regeneration capacity due to insufficient blood vessels and chondrocytes in the region. Biomaterial‐assisted tissue engineering has shown great potential in cartilage regeneration. However, there are still many worries over the uses of exogenous growth factors, stem cells and scaffolds. To address these concerns, here a dynamic proteinaceous hydrogel with a self‐recruiting ability of cartilage‐inducing factor for in situ cartilage regeneration is reported. The dynamic hydrogel (Pep‐GelSH) is prepared by using thiol‐modified gelatin and thiol‐capped TGF‐β1‐affinity peptide through the Au‐S coordination. The injectability and self‐recovery of Pep‐GelSH hydrogel enabled not only minimally invasive implantation but also the adaptability of the scaffold to irregular defect shapes. Meanwhile, the dynamic hydrogel showed improved adherence to the host tissue and allowed quick infiltration of host cells. More importantly, the hydrogel significantly enhanced local enrichment of endogenous TGF‐β1 and led to the recruitment of stem cells in vivo. After implantation, the hydrogel scaffold triggered the innate repair capacity of cartilage defects by successively promoting stem cells recruitment, infiltration and differentiation, resulting in significantly enhanced chondrogenesis and improved cartilage repair. Therefore, the study in this work may provide a feasible and promising approach for in situ cartilage regeneration. [ABSTRACT FROM AUTHOR]

A burn is a type of injury to the skin or other tissues caused by heat, chemicals, electricity, sunlight, or radiation. Burn injuries have been proven to have the potential for long-term detrimental effects on the human body. The conventional therapeutic approaches are not able to effectively and easily heal these burn wounds completely. The main potential drawbacks of these treatments include hypertrophic scarring, contracture, infection, necrosis, allergic reactions, prolonged healing times, and unsatisfactory cosmetic results. The existence of these drawbacks and limitations in current treatment approaches necessitates the need to search for and develop better, more efficient therapies. The regenerative potential of microRNAs (miRNAs) and the exosomal miRNAs derived from various cell types, especially stem cells, offer advantages that outweigh traditional burn wound healing treatment procedures. The use of multiple types of stem cells is gaining interest due to their improved healing efficiency for various applications. Stem cells have several key distinguishing characteristics, including the ability to promote more effective and rapid healing of burn wounds, reduced inflammation levels at the wound site, and less scar tissue formation and fibrosis. In this review, we have discussed the stages of wound healing, the role of exosomes and miRNAs in improving thermal-induced wounds, and the impact of miRNAs in preventing the formation of hypertrophic scars. Research studies, pre-clinical and clinical, on the use of different cell-derived exosomal miRNAs and miRNAs for the treatment of thermal burns have been documented from the year 2000 up to the current time. Studies show that the use of different cell-derived exosomal miRNAs and miRNAs can improve the healing of burn wounds. The migration of exosomal miRNAs to the site of a wound leads to inhibition of apoptosis, induction of autophagy, re-epithelialization, granulation, regeneration of skin appendages, and angiogenesis. In conclusion, this study underscores the importance of integrating miRNA and exosome research into treatment strategies for burn injuries, paving the way for novel therapeutic approaches that could significantly improve patient outcomes and recovery times. [ABSTRACT FROM AUTHOR]

Sebaceous glands (SG) are essential for maintaining skin integrity, as their lipid-rich secretion (sebum) lubricates and protects the epidermis and hairs. In addition, these glands have an emerging role in immunomodulation and may affect whole-body energy metabolism, besides being an appealing model for research in topics as lipogenesis, stem cell biology and tumorigenesis. In spite of the increasing interest in studying SGs pathophysiology, sebocyte cell–cell and cell–matrix adhesion processes have been only superficially examined, and never in a systematic way. This is regrettable considering the key role of cellular adhesion in general, the specific expression pattern of indivdual junctional complexes, and the reports of structural changes in SGs after altered expression of adhesion-relevant proteins. Here, we review the available information on structural and functional aspects of cell–cell and cell–matrix junctions in sebocytes, and how these processes change under pathological conditions. This information will contribute for better understanding sebocyte differentiation and sebum secretion, and may provide hints for novel therapeutic strategies for skin diseases. [ABSTRACT FROM AUTHOR]

Clathrin-mediated endocytosis (CME) is a critical trafficking process that begins when an elaborate endocytic protein network is established at the plasma membrane. Interaction of early endocytic proteins with anionic phospholipids and/or cargo has been suggested to trigger CME initiation. However, the exact mechanism by which CME sites are initiated has not been fully elucidated. In the budding yeast Saccharomyces cerevisiae, higher levels of anionic phospholipids and cargo molecules exist in the newly formed daughter cell compared to the levels in the mother cell during polarized growth. Taking advantage of this asymmetry, we quantitatively compared CME proteins in S. cerevisiae mother versus daughter cells, observing differences in the dynamics and composition of key endocytic proteins. Our results show that CME site initiation occurs preferentially on regions of the plasma membrane with a relatively higher density of endocytic cargo and/or acidic phospholipids. Furthermore, our combined live cell-imaging and yeast genetics analysis provided evidence for a molecular mechanism in which CME sites are initiated when Yap1801 and Yap1802 (yeast CALM/AP180) and Syp1 (yeast FCHo1/2) coordinate with anionic phospholipids and cargo molecules to trigger Ede1 (yeast Eps15)-centric CME initiation complex assembly at the plasma membrane. Clathrin-mediated endocytosis (CME) is one of the main trafficking processes, but the mechanism that initiates CME sites remain unclear. These authors show that yeast CALM/AP180 and FCHo1/2 adaptor proteins interact with Eps15 to promote CME initiation. [ABSTRACT FROM AUTHOR]

AbstractCancer stem cells (CSCs) are cancer cells that can self-renew and give rise to tumors. The multipotency of CSCs enables the generation of diverse cancer cell types and their potential for differentiation and resilience against chemotherapy and radiation. Additionally, specific biomarkers have been identified for them, such as CD24, CD34, CD44, CD47, CD90, and CD133. The CSC model suggests that a subset of CSCs within tumors is responsible for tumor growth. The tumor microenvironment (TME), including fibroblasts, immune cells, adipocytes, endothelial cells, neuroendocrine (NE) cells, extracellular matrix (ECM), and extracellular vesicles, has a part in shielding CSCs from the host immune response as well as protecting them against anticancer drugs. The regulation of cancer stem cell plasticity by cancer-associated fibroblasts (CAFs) occurs through specific signaling pathways that differ among various types of cancer, utilizing the IGF-II/IGF1R, FAK, and c-Met/FRA1/HEY1 signaling pathways. Due to the intricate dynamics of CSC proliferation, controlling their growth necessitates innovative approaches and much more research. Our current review speculates an outline of how the TME safeguards stem cells, their interaction with CSCs, and the involvement of the immune and inflammatory systems in CSC differentiation and maintenance. Several technologies have the ability to identify CSCs; however, each approach has limitations. We discuss how these methods can aid in recognizing CSCs in several cancer types, comprising brain, breast, liver, stomach, and colon cancer. Furthermore, we explore different immunotherapeutic strategies targeting CSCs, including stimulating cancer-specific T cells, modifying immunosuppressive TMEs, and antibody-mediated therapy targeting CSC markers. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Materials and Methods Results Conclusion Dental pulp stem cells (DPSCs) have been extensively used for tissue regeneration owing to their notable capabilities. Insulin‐like growth factor‐binding protein 5 (IGFBP5) regulates osteogenic differentiation of mesenchymal stem cells (MSCs); however, the underlying regulatory mechanisms require further investigation.Carboxyfluorescein succinimidyl ester, an alkaline phosphatase (ALP) activity assay and Alizarin Red staining were used to reveal the role of IGFBP5 in DPSCs. Protein expression levels were determined using western blotting. Immunofluorescence was used to observe cell sub‐localisation. Subcutaneous transplantation in nude mice was used to observe the osteogenesis of DPSCs in vivo.IGFBP5 enhanced the proliferation and osteogenic differentiation of DPSCs. Deletion of the nuclear localisation sequence (NLS) of IGFBP5 prevented its nuclear import and abolished all its promoting effects on DPSCs; ivermectin stimulation attenuated the enhancement of ALP activity by IGBFP5. Bone‐like tissue formation promoted by IGFBP5 in vivo vanishes when the NLS is deleted. Inhibition of IGFBP5 nuclear import attenuated the IGFBP5‐induced phosphorylation of JNK (p‐JNK) and phosphorylated ERK (p‐ERK) in DPSCs.Our findings suggest that cell proliferation and osteogenic differentiation effects exerted by IGFBP5 on DPSCs are closely associated with their entry into the nucleus, thereby providing a novel potential target for tissue regeneration. [ABSTRACT FROM AUTHOR]

Pax‐6 emerges as a critical transcription factor that guides the fate of stem cells towards neural lineages. Its expression influences the differentiation of neural progenitors into diverse neuronal subtypes, glial cells, and other neural cell types. Pax‐6 operates with other regulatory factors to ensure the precise patterning and organization of the developing nervous system. The intricate interplay between Pax‐6 and other signaling pathways, transcription factors, and epigenetic modifiers underpins the complicated balance between stem cell maintenance, proliferation, and differentiation in neuroectodermal and ocular contexts. Dysfunction of Pax‐6 can lead to a spectrum of developmental anomalies, underscoring its importance in these processes. This review highlights the essential role of Pax‐6 expression in neuroectodermal and ocular stem cells, shedding light on its significance in orchestrating the intricate journey from stem cell fate determination to the emergence of diverse neural and ocular cell types. The comprehensive understanding of Pax‐6 function gained from a developmental biology perspective offers valuable insights into normal development and potential therapeutic avenues for neuroectodermal and ocular disorders. [ABSTRACT FROM AUTHOR]

Pseudoxanthoma elasticum (PXE) is a rare metabolic disease with autosomal recessive inheritance. The manifestation in PXE is represented by retinal complications, pseudoxanthomas of the skin folding areas, and arterial calcification. The retinal complications are caused by the calcification of Bruch's membrane beneath retinal pigment epithelial cells (RPE) that can lead to retinal macular degeneration. The exact mechanism for the retinal pathophysiology is not known, and patients have variable symptoms and findings. Two induced pluripotent stem cell (hiPSC) lines from a patient carrying the common homozygous mutation c.3421C > T, p.Arg1141X in the ATP‐binding cassette transporter gene (ABCC6; OMIM264800) were established and fully characterized. Then, RPE cells were differentiated, and molecular and functional characterization was conducted as a comparison to healthy controls. Data demonstrated that PXE‐specific high‐quality hiPSC lines can be established from a skin biopsy regardless of the skin‐related disease phenotype and disease‐specific RPE differentiation is feasible. The molecular and functional assessment of the PXE‐specific RPE indicated increased pigmentation and reduced epithelial barrier functions as well as phagocytosis activity as compared to healthy controls. Although preliminary data, this indicates possible RPE‐dependent factors that might explain the individual vulnerability of the retinas for macular degeneration in PXE. Future validation of the novel findings with additional PXE patients will be important. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction Methods Results Conclusions The standard flow cytometry method for viability testing using 7‐aminoactinomycin D (7‐AAD) determines cells in necrosis and late apoptosis. The colony‐forming unit (CFU) assay, which evaluates the proliferation ability of HSCs, is also used in graft quality assessment despite known deficiencies that make this assay impractical in routine clinical settings. The aim was to compare the effectiveness of the flow cytometry 7‐AAD/annexin V method with the 7‐AAD method in assessing the quality of HSCs in autologous and allogeneic peripheral blood stem cell (PBSC) products.Thirty autologous and 30 allogeneic fresh and thawed cryopreserved PBSC products were included in this study. The viability of HSCs was determined using the 7‐AAD method and 7‐AAD/annexin V method on a flow cytometer, while their clonogenic capacity was assessed by CFU assay.There was an excellent correlation for CD34+ cell viability between the 7‐AAD and the 7‐AAD/annexin V method for fresh samples (Rs = 0.930, p < 0.001) and a good correlation for thawed PBSC samples (Rs = 0.739, p < 0.001). Excellent correlation was observed for post‐thaw CD34+ cell recovery between the two methods for viability (Rs = 0.980, p < 0.001). Statistical analysis showed a weak correlation between CFU‐GM recovery and CD34+ cell recovery, regardless of which viability testing method was used (7‐AAD method p = 0.021, Rs = 0.298; 7‐AAD/annexin V method p = 0.029, Rs = 0.282).Results of this study showed that in the quality assessment of cryopreserved PBSC product viability, the 7‐AAD/annexin V method had no added value compared to the 7‐AAD method, which was suitable enough for routine quality control of cryopreserved autologous and allogeneic PBSC samples. [ABSTRACT FROM AUTHOR]

Pancreatic β cells secrete insulin in response to elevated levels of glucose. Stem cell derived β (SCβ) cells aim to replicate this glucose-stimulated insulin secretion (GSIS) function, but current preparations cannot provide the same level of insulin as natural β cells. Here, we develop an assay to measure GSIS at the single cell level to investigate the functional heterogeneity of SCβ cells and donor-derived islet cells. Our assay involves randomly depositing single cells and insulin capture microbeads in opentop nanowells (40 × 40 × 55 μm³ ) fabricated on glass-bottom imaging microwell plates. Insulin secreted from single cells is captured on microbeads and then stained using a detection antibody. The nanowell microstructure limits diffusion of secreted insulin. The glass substrate provides an optically flat surface for quantitative microscopy to measure the concentration of secreted insulin. We used this approach to measure GSIS from SCβ cells and donor-derived islet cells after 15 minutes exposure to 3.3 mM and 16.7 mM glucose. Both cell types exhibited significant GSIS heterogeneity, where elite cells (<20%) produced the majority of the secreted insulin (55–78%). This assay provides an immediate readout of single cell glucose-stimulated insulin secretion in a flexible well plate-based format. [ABSTRACT FROM AUTHOR]

The possibility to remotely manipulate intracellular pathways in single cells is among the current goals of regenerative medicine, demanding new strategies to enhance tissue repair and reprogram stem cell activity. Plasmonic nanomaterials are addressing this need, due to improvements in the controlled synthesis allowing convenient regulation and precise thermal positioning. Leveraging on the thermal properties of gold nanoprisms (AuNPs) and on the unparalleled regenerating capabilities of the small invertebrate Hydra vulgaris, here the possibility to activate the molecular machinery underlying the animal regeneration by using AuNPs and applying regular pulses of near infrared irradiation (NIR) is shown. The efficiency of the head regeneration, reproductive capability, and stem cell proliferation rate are boosted by the AuNP photostimulation, indicating NIR triggered hyperthermia as new tool to enhance tissue regeneration. By transcriptional profiling of key developmental genes in animals exposed to external heat or irradiated an estimation of the heat developed in vivo by intracellular nanoheaters is obtained, revealing Hydra as a living thermometer to test performance of plasmonic materials. These results shed light on a novel function of heat emitting nanoparticles to control cell stemness through the activation of molecular pathways that can be targeted for regenerative medicine or wound healing strategies. [ABSTRACT FROM AUTHOR]

During the process of muscle regeneration post‐injury in adults, muscle stem cells (MuSCs) function is facilitated by neighboring cells within the pro‐regenerative niche. However, the precise mechanism triggering the initiation of signaling in the pro‐regenerative niche remains unknown. Using single‐cell RNA sequencing, 14 different muscle cells are comprehensively mapped during the initial stage following injury. Among these, macrophages and fibro‐adipogenic progenitor cells (FAPs) exhibit the most pronounced intercellular communication with other cells. In the FAP subclusters, the study identifies an activated FAP phenotype that secretes chemokines, such as CXCL1, CXCL5, CCL2, and CCL7, to recruit macrophages after injury. Il1rl1, encoding the protein of the interleukin‐33 (IL‐33) receptor, is identified as a highly expressed signature surface marker of the FAP phenotype. Following muscle injury, autocrine IL‐33, an alarmin, has been observed to activate quiescent FAPs toward this inflammatory phenotype through the IL1RL1‐MAPK/NF‐κB signaling pathway. Il1rl1 deficiency results in decreased chemokine expression and recruitment of macrophages, accompanied by impaired muscle regeneration. These findings elucidate a novel mechanism involving the IL‐33/IL1RL1 signaling pathway in promoting the activation of FAPs and facilitating muscle regeneration, which can aid the development of therapeutic strategies for muscle‐related disorders and injuries. [ABSTRACT FROM AUTHOR]

We previously showed that inhibition of glycolysis in cutaneous squamous cell carcinoma (SCC)-initiating cells had no effect on tumorigenesis, despite the perceived requirement of the Warburg effect, which was thought to drive carcinogenesis. Instead, these SCCs were metabolically flexible and sustained growth through glutaminolysis, another metabolic process frequently implicated to fuel tumorigenesis in various cancers. Here, we focused on glutaminolysis and genetically blocked this process through glutaminase (GLS) deletion in SCC cells of origin. Genetic deletion of GLS had little effect on tumorigenesis due to the up-regulated lactate consumption and utilization for the TCA cycle, providing further evidence of metabolic flexibility. We went on to show that posttranscriptional regulation of nutrient transporters appears to mediate metabolic flexibility in this SCC model. To define the limits of this flexibility, we genetically blocked both glycolysis and glutaminolysis simultaneously and found the abrogation of both of these carbon utilization pathways was enough to prevent both papilloma and frank carcinoma. [ABSTRACT FROM AUTHOR]

Differentiation of female germline stem cells into a mature oocyte includes the expression of RNAs and proteins that drive early embryonic development in Drosophila. We have little insight into what activates the expression of these maternal factors. One candidate is the zinc-finger protein OVO. OVO is required for female germline viability and has been shown to positively regulate its own expression, as well as a downstream target, ovarian tumor, by binding to the transcriptional start site (TSS). To find additional OVO targets in the female germline and further elucidate OVO’s role in oocyte development, we performed ChIP-seq to determine genome-wide OVO occupancy, as well as RNA-seq comparing hypomorphic and wild type rescue ovo alleles. OVO preferentially binds in close proximity to target TSSs genome-wide, is associated with open chromatin, transcriptionally active histone marks, and OVO-dependent expression. Motif enrichment analysis on OVO ChIP peaks identified a 5’-TAACNGT-3’ OVO DNA binding motif spatially enriched near TSSs. However, the OVO DNA binding motif does not exhibit precise motif spacing relative to the TSS characteristic of RNA polymerase II complex binding core promoter elements. Integrated genomics analysis showed that 525 genes that are bound and increase in expression downstream of OVO are known to be essential maternally expressed genes. These include genes involved in anterior/posterior/ germ plasm specification (bcd, exu, swa, osk, nos, aub, pgc, gcl), egg activation (png, plu, gnu, wisp, C(3)g, mtrm), translational regulation (cup, orb, bru1, me31B), and vitelline membrane formation (fs(1)N, fs(1)M3, clos). This suggests that OVO is a master transcriptional regulator of oocyte development and is responsible for the expression of structural components of the egg as well as maternally provided RNAs that are required for early embryonic development. [ABSTRACT FROM AUTHOR]

Apoptotic vesicles (apoVs) play a vital role in various physiological and pathological conditions. However, we have yet to fully understand their precise biological effects in rescuing impaired mesenchymal stem cells (MSCs). Here, we proved that systemic infusion of MSCs derived from wild-type (WT) mice rather than from ovariectomized (OVX) mice effectively improved the osteopenia phenotype and rescued the impaired recipient MSCs in osteoporotic mice. Meanwhile, apoVs derived from WT MSCs (WT apoVs) instead of OVX apoVs efficiently restored the impaired biological function of OVX MSCs and their ability to improve osteoporosis. Mechanistically, the reduced miR-145a-5p expression hindered the osteogenic differentiation and immunomodulatory capacity of OVX MSCs by affecting the TGF-β/Smad 2/3-Wnt/β-catenin signaling axis, resulting in the development of osteoporosis. WT apoVs directly transferred miR-145a-5p to OVX MSCs, which were then reused to restore their impaired biological functions. The differential expression of miR-145a-5p is responsible for the distinct efficacy between the two types of apoVs. Overall, our findings unveil the remarkable potential of apoVs, as a novel nongenetic engineering approach, in rescuing the biological function and therapeutic capability of MSCs derived from patients. This discovery offers a new avenue for exploring apoVs-based stem cell engineering and expands the application scope of stem cell therapy, contributing to the maintenance of bone homeostasis through a previously unrecognized mechanism. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease(COPD) is an inflammatory disease characterized by the progressive and irreversible structural and functional damage of lung tissue. Although COPD is a significant global disease burden, the available treatments only ameliorate the symptoms, but cannot reverse lung damage. Researchers in regenerative medicine have examined the use of stem cell transplantation for treatment of COPD and other diseases because these cells have the potential for unlimited self-renewal and the ability to undergo directed differentiation. Stem cells are typically classified as embryonic stem cells, induced pluripotent stem cells, and adult stem cells (which includes mesenchymal stem cells [MSCs]), each with its own advantages and disadvantages regarding applications in regenerative medicine. Although the heterogeneity and susceptibility to senescence of MSCs make them require careful consideration for clinical applications. However, the low tumourigenicity and minimal ethical concerns of MSCs make them appear to be excellent candidates. This review summarizes the characteristics of various stem cell types and describes their therapeutic potential in the treatment of COPD, with a particular emphasis on MSCs. We aim to facilitate subsequent in-depth research and preclinical applications of MSCs by providing a comprehensive overview. [ABSTRACT FROM AUTHOR]

Background: Despite a high incidence of colorectal carcinoma, data regarding genetic aberrations in colorectal carcinoma (CRC) patients in Pakistan is scarce. This study aimed to determine the frequency of BRAFV600E mutations in colorectal carcinoma tissue in the Pakistani population and to associate BRAFV600E expression with CD133, a marker of colorectal stem cells, and CDX2 marker of differentiation. Methods: Sanger Sequencing of exon 15 (426 bp) including the hotspot V600E was performed on formalin-fixed-paraffin-embedded (FFPE) CRC tissue samples of 115 patients. The samples were subjected to immunohistochemistry (IHC) to assess the expression of BRAFV600E, CDX2, and CD133. Additionally, homology modelling and docking were performed to investigate novel deletions revealed in sequencing. Results: Twenty-four (20.8%) BRAF variants were identified in the coding region, with V600E mutations detected in 14 (12.2%)cases (GenBank: PP003258.1; Pop Set: 2678087296). Moreover, a wide spectrum of novel non-V600E mutations (8.6%) were identified, including deletions and missense variations. In-silico analysis revealed that due to large deletions in the coding region of three samples, the affinity of the anti-BRAF drugs (Encorafenib and Vemurafenib) for the active site decreased in comparison to the wild type. The IHC analysis showed that BRAFV600E expression was significantly associated with CD133 expression (χ2(1, n=115) = 26.351; p = < 0.001) and with CDX2 expression (χ2(1, n=115) = 14.88; p = 0.001). Multivariate analysis using binary logistic regression revealed association of BRAFV600E mutations with age (OR = 1.123; CI = 1.024–1.232; p = 0.014), gender (OR = 0.071; CI = 0.006–0.831; p = 0.035), grade (0.007; CI = 0-0.644) and CD133 expression (OR = 65.649; CI = 2.153-2001.556; p = 0.016). Conclusion: The present study demonstrates a notably high V600E frequency (12.2%) in comparison to global reported data, which ranges from 0.4 to 18%. This finding reflects the importance of upfront BRAF testing of the genetically distinct population of Pakistan. Previously unreported mutations identified in the sample may be of clinical significance and warrant further investigation. The concomitant high expression and significant association between CD133 and BRAFV600E represent vital actionable genes that may be targeted together to improve CRC patient management. [ABSTRACT FROM AUTHOR]

Chronic myelomonocytic leukemia (CMML) is a rare blood cancer of older adults (3 in every 1,000,000 persons) characterized by poor survival and lacking effective mutation-specific therapy. Mutations in the ubiquitin ligase Cbl occur frequently in CMML and share biological and molecular features with a clonal disease occurring in children, juvenile myelomonocytic leukemia (JMML). Here we analyzed the clinical presentations, molecular features and immunophenotype of CMML patients with CBL mutations enrolled in a prospective Phase II clinical trial stratified according to molecular markers. Clinically, CBL mutations were associated with increased bone marrow blasts at diagnosis, leukocytosis and splenomegaly, similar to patients harboring NRAS or KRAS mutations. Interestingly, 64% of patients presented with more than one CBL variant implying a complex subclonal architecture, often with co-occurrence of TET2 mutations. We found CBL mutations in CMML frequently clustered in the RING domain in contrast to JMML, where mutations frequently involve the linker helix region (P<0.0001). According to our comparative alignment of available X-ray structures, mutations in the linker helix region such as Y371E give rise to conformational differences that could be exploited by targeted therapy approaches. Furthermore, we noted an increased percentage of CMML CD34+ stem and progenitor cells expressing CD116 and CD131 in all CBL mutant cases and increased CD116 receptor density compared to healthy controls, similar to CMML overall. In summary, our data demonstrate that CBL mutations are associated with distinct molecular and clinical features in CMML and are potentially targetable with CD116-directed immunotherapy. [ABSTRACT FROM AUTHOR]

Stem cells, ideal for the tissue repair and regeneration, possess extraordinary capabilities of multidirectional differentiation and self‐renewal. However, the limited spontaneous differentiation potential makes it challenging to harness them for tissue repair without external intervention. Although conventional approaches using biomolecules, small organic molecules, and ions have shown specific and effective functions, they face challenges such as in vivo diffusion and degradation, poor internalization, and side effects on adjacent cells. Nanoengineered biomaterials offer a solution by solidifying and nanosizing these soluble regulating molecules and ions, facilitating their uptake by stem cells. Once inside lysosomes, these nanoparticles release their contents in a controlled “molecule or ion storm,” efficiently altering the intracellular biological and chemical microenvironment to tune the differentiation of stem cells. This newly emerged approach for regulating stem cell fate has attracted much attention in recent years. This method has shown promising results and is poised to enhance clinical stem cell therapy. This review provides an overview of the design principles for nanoengineered biomaterials, discusses the categories and characteristics of nanoparticles, summarizes the application of nanoparticles in tissue repair and regeneration, and discusses the direction of nanoparticle‐enhanced stem cell therapy and prospects for its clinical application in regenerative medicine. [ABSTRACT FROM AUTHOR]

Background Methods and Results Conclusions Allogeneic hematopoietic cell transplantation remains limited when stem cell registrants cannot be contacted, are not medically fit, are unavailable, or unwilling to proceed. In a recent report, registrants who were prior blood donors were more likely to be available for donation. In this study, we analyzed extent to which recruiting blood donors to the Canadian Blood Services Stem Cell Registry (CBS SCR) can meet targets for ethnic diversity, age, and proximity to collection facilities.We analyzed 124,496 active blood donors on July 1, 2023 regarding the criteria for recruitment to the CBS SCR. A total of 40,518 (32%) were younger than 36 years of age and 49% were first‐time donors (potential new recruits year over year). The ethnicity of blood donors younger than 36 years aligns more closely with the 2021 Canadian census compared to stem cell donors who were also previous blood donors, and to the current total inventory of all registrants on the CBS SCR. Of the blood donors, certain ethnic groups, including Black, Chinese, and First Nations/Indigenous, remain underrepresented. A greater proportion of active whole blood donors live within 400 km of a stem cell collection center (91%) compared to stem cell donors who donated during the past 10 years (80%).Recruitment of blood donors offers an opportunity to improve the ethnic diversity of the CBS SCR and increase proximity of registrants to stem cell collection centers. The potential improved availability of registrants when matched to patients requires confirmation. [ABSTRACT FROM AUTHOR]

Polycomb proteins are a fundamental repressive system that plays crucial developmental roles by orchestrating cell-type-specific transcription programs that govern cell identity. Direct alterations of Polycomb activity are indeed implicated in human pathologies, including developmental disorders and cancer. General Polycomb repression is coordinated by three distinct activities that regulate the deposition of two histone post-translational modifications: tri-methylation of histone H3 lysine 27 (H3K27me3) and histone H2A at lysine 119 (H2AK119ub1). These activities exist in large and heterogeneous multiprotein ensembles consisting of common enzymatic cores regulated by heterogeneous non-catalytic modules composed of a large number of accessory proteins with diverse biochemical properties. Here, we have analyzed the current molecular knowledge, focusing on the functional interaction between the core enzymatic activities and their regulation mediated by distinct accessory modules. This provides a comprehensive analysis of the molecular details that control the establishment and maintenance of Polycomb repression, examining their underlying coordination and highlighting missing information and emerging new features of Polycomb-mediated transcriptional control. The Polycomb machinery is a major repressive system essential for development, stem cell, and tissue homeostasis directly involved in several human pathologies. Tamburri et al. explored the molecular complexity by which different core enzymatic activities and regulatory modules coordinate to establish and maintain repressive domains to control cell transcriptional identities. [ABSTRACT FROM AUTHOR]

Pathological scars (PS) are involved in the excessive response of inflammation and overactivation of myofibroblasts. Herein, a novel microneedle (MN) patch based on the adipose‐derived stem cell concentrated conditioned medium (ADSCC‐CM) cross‐linked keratin hydrogel is developed to load triamcinolone acetonide (TA), thereby achieving the dual‐drug delivery of ADSCC‐CM and TA to simultaneously reduce the inflammation and guide myofibroblast behaviors. Results not only confirm the ability of ADSCC‐CM to drive the formation of keratin‐based hydrogel, but also verify the dual‐drug release capacities of the hydrogel‐developed MNs (TA@AC‐MN). Using human hyperplastic scar fibroblast (HSF), the combination of ADSCC‐CM and TA demonstrates a pronounced synergistic effect in mitigating the detrimental effects of the inflammatory microenvironment on HSFs, including suppressing the production of reactive oxygen species and attenuating the expression of inflammatory factors. Compared with the clinically used TA, TA@AC‐MN promotes scar biomimetic repair (i.e., optimizing the proportion of collagen and increasing the tissue tensile strength). This study demonstrates that TA@AC‐MN has the capacity to provide a self‐managing and minimally invasive therapeutic strategy for PS. [ABSTRACT FROM AUTHOR]

Recent advances in single‐cell transcriptomic data have greatly expanded our understanding of both spermatogenesis and the molecular mechanisms of male infertility. However, this growing wealth of data could also shed light on a seemingly unrelated biological problem: the genetic basis of mammalian brain size expansion throughout evolution. It is now increasingly recognized that the testis and brain share many cellular and molecular similarities including pivotal roles for the RAS/MAPK and PI3K/AKT/mTOR pathways, mutations in which are known to have a pronounced impact on cell proliferation. Most notably, in the stem cell lineages of both organs, new mutations have been shown to increase cellular output over time. These include ‘selfish’ mutations in spermatogonial stem cells, which disproportionately increase the proportion of mutant sperm, and—to draw a parallel—human‐specific mutations in neural stem cells which, by increasing the number of neurons, have been implicated in neocortical expansion. Here we speculate that the origin for many ‘expansion’‐associated mutations is the male germline and that as such, a deeper understanding of the mechanisms controlling testicular turnover may yield fresh insight into the biology and evolution of the brain. [ABSTRACT FROM AUTHOR]

Plants are capable of altering root growth direction to curtail exposure to a saline environment (termed halotropism). The root cap that surrounds root tip meristematic stem cells plays crucial roles in perceiving and responding to environmental stimuli. However, how the root cap mediates root halotropism remains undetermined. Here, we identified a root cap-localized NAC transcription factor, SOMBRERO (SMB), that is required for root halotropism. Its effect on root halotropism is attributable to the establishment of asymmetric auxin distribution in the lateral root cap (LRC) rather than to the alteration of cellular sodium equilibrium or amyloplast statoliths. Furthermore, SMB is essential for basal expression of the auxin influx carrier gene AUX1 in LRC and for auxin redistribution in a spatiotemporally-regulated manner, thereby leading to directional bending of roots away from higher salinity. Our findings uncover an SMB-AUX1-auxin module linking the role of the root cap to the activation of root halotropism. This study reports that the SOMBRERO, a root cap-localized transcription factor, determines root halotropic response to salt stress via spatiotemporally modulating AUX1-depdenent auxin redistribution in the root tip. [ABSTRACT FROM AUTHOR]

Glioblastoma organoids (GBOs) serve as a powerful and reliable tool to study glioblastoma stem cells (GSCs) and glioblastoma (GBM). GBOs can be derived from different materials using different methods. To identify the predominant generation methods and the most applications of GBOs, we searched four databases (PubMed, Embase, Web of Science, and Wiley Online Laboratory) from August 2021 to August 2023. After screening, 42 out of 295 articles were included and analyzed. GBOs in these articles were generated using only one material, such as tumor tissues, tumor cells, and gene-edited multifunctional stem cells, or simultaneously using two materials, such as tumor cells and normal organoids. Methodologically, direct cultivation of GBM cells or tissues was the most commonly used method to generate GBOs. Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) were the frequently used multifunctional stem cells to generate GBOs by simultaneously silencing P53, NF1, and PTEN using CRISPR/Cas9. In terms of applications, GBOs generated by direct cultivation of GBM tissue had the most applications, including molecular mechanisms, therapy, and culture technique. This review provides a theoretical reference for selecting an appropriate method to generate GBOs when studying GSCs and GBM. [ABSTRACT FROM AUTHOR]

Background: Tongue defects have several etiologies and significantly affect the quality of life. This study was conducted to compare the regenerative potential of erythropoietin (EPO)-loaded hydrogel and adipose derived stem cell (ADSC) secretome on tongue dorsum defects focusing on the role of anti-inflammatory M2 macrophage phenotype. Methods: Rats were subjected to induction of mechanical circular defects on the dorsal surface of the tongue, then divided into three groups; Group I (control): received 0.1 ml phosphate buffered saline, Group II (EPO): received 5000 U/kg EPO-hydrogel, and Group III (ADSC-Secretome): received 0.1 ml ADSC-Secretome. Treatments were injected circumferentially around wound margins after induction. Seven and fourteen days after treatment, specimens were obtained and processed for histological and immunohistochemical staining followed by the relevant histomorphometric and statistical analyses. Results: Seven days after treatment, groups II and III presented defects with some epithelial regeneration at the lateral margins, while the center of the defect showed granulation tissue with much inflammatory cells. The base of the defects showed some muscle fibers and new blood vessels, however group III showed more enhanced neovascularization. Fourteen days after therapeutic intervention, group II defects were completely covered with epithelium showing a thin keratin layer with regular rete pegs interdigitating with the underlying connective tissue papillae, but tongue papillae were not restored. Group III expressed much better healing with developing filiform papillae. The connective tissue showed more vascularity and well-arranged muscle bundles. Both treated groups showed a significant decrease in defect depth and significant increase in anti-inflammatory macrophages compared to the control group at both time intervals, however there was no significant difference between the two treated groups. Conclusion: Both treatments showed promising and comparable results in the treatment of tongue defects reducing inflammation and restoring tongue histological architecture with significant upregulation of M2 macrophage. [ABSTRACT FROM AUTHOR]

A major next step in hematopoietic stem cell (HSC) biology is to enhance our quantitative understanding of cellular and evolutionary dynamics involved in undisturbed hematopoiesis. Mathematical models have been and continue to be key in this respect, and are most powerful when parameterized experimentally and containing sufficient biological complexity. In this paper, we use data from label propagation experiments in mice to parameterize a mathematical model of hematopoiesis that includes homeostatic control mechanisms as well as clonal evolution. We find that nonlinear feedback control can drastically change the interpretation of kinetic estimates at homeostasis. This suggests that short-term HSC and multipotent progenitors can dynamically adjust to sustain themselves temporarily in the absence of long-term HSCs, even if they differentiate more often than they self-renew in undisturbed homeostasis. Additionally, the presence of feedback control in the model renders the system resilient against mutant invasion. Invasion barriers, however, can be overcome by a combination of age-related changes in stem cell differentiation and evolutionary niche construction dynamics based on a mutant-associated inflammatory environment. This helps us understand the evolution of e.g., TET2 or DNMT3A mutants, and how to potentially reduce mutant burden. [ABSTRACT FROM AUTHOR]

Male infertility can be caused by chromosomal abnormalities, mutations and epigenetic defects. Epigenetic modifiers pre-program hundreds of spermatogenic genes in spermatogonial stem cells (SSCs) for expression later in spermatids, but it remains mostly unclear whether and how those genes are involved in fertility. Here, we report that Wfdc15a, a WFDC family protease inhibitor preprogrammed by KMT2B, is essential for spermatogenesis. We found that Wfdc15a is a non-canonical bivalent gene carrying both H3K4me3 and facultative H3K9me3 in SSCs, but is later activated along with the loss of H3K9me3 and acquisition of H3K27ac during meiosis. We show that WFDC15A deficiency causes defective spermiogenesis at the beginning of spermatid elongation. Notably, depletion of WFDC15A causes substantial disturbance of the testicular protease-antiprotease network and leads to an orchitislike inflammatory response associated with TNFa expression in round spermatids. Together, our results reveal a unique epigenetic program regulating innate immunity crucial for fertility. [ABSTRACT FROM AUTHOR]

Simple Summary: Equine laminitis is a serious condition causing severe pain and lameness in horses, often leading to euthanasia. This study developed a lab model to better understand laminitis using keratinocytes which were exposed to conditions simulating the disease. This research showed that adding muscle-derived stem cells helped protect and restore the keratinocytes' metabolism. These results highlight the potential of stem cell therapy in treating laminitis, offering new hope for managing this debilitating disease in horses. Laminitis in horses is a crippling condition marked by the deterioration of the dermal–epidermal interface, leading to intense lameness and discomfort, often necessitating euthanasia. This study aimed to establish an in vitro model of laminitis using a continuous keratinocyte cell line exposed to anoxia–reoxygenation and an activated neutrophil supernatant. A significant decrease in the keratinocytes' metabolism was noted during the reoxygenation period, indicative of cellular stress. Adding muscle-derived mesenchymal stem/stromal cells during the reoxygenation demonstrated a protective effect, restoring the keratinocytes' metabolic activity. Moreover, the incubation of the keratinocytes with either an activated neutrophil supernatant or myeloperoxidase alone induced increased keratinocyte myeloperoxidase activity, which was modulated by stem cells. These findings underscore the potential of muscle-derived mesenchymal stem/stromal cells in mitigating inflammation and restoring keratinocyte metabolism, offering insights for future cell therapy research in laminitis treatment. [ABSTRACT FROM AUTHOR]

Simple Summary: Breast cancer remains a major health issue in the United States and around the world. While progress has been made in curing most types of breast cancer, there are currently no effective cures for a subtype called 'triple-negative' breast cancer. We have identified a gene named BORG that, based on experiments in cultured human cells and mice, plays an important role in triple-negative breast cancer. Here, we study the function of this gene in a large group of human triple-negative breast cancers and show that when the level of expression of this gene is high, tumors become more invasive and develop 'triple-negative'-like properties. Even in non-triple-negative tumors, high levels of expression of this gene are associated with more aggressive tumor behavior and poor response to therapy. Based on these validation studies in human tumors, we hope to leverage mechanistic vulnerabilities in BORG action to one day advance novel therapeutic strategies to alleviate hard-to-cure triple-negative breast tumors. Background/Objectives: Long noncoding RNAs (lncRNAs) are known to play key roles in breast cancers; however, detailed mechanistic studies of lncRNA function have not been conducted in large cohorts of breast cancer tumors, nor has inter-donor and inter-subtype variability been taken into consideration for these analyses. Here we provide the first identification and annotation of the human BORG lncRNA gene. Methods/Results: Using multiple tumor cohorts of human breast cancers, we show that while BORG expression is strongly induced in breast tumors as compared to normal breast tissues, the extent of BORG induction varies widely between breast cancer subtypes and even between different tumors within the same subtype. Elevated levels of BORG in breast tumors are associated with the acquisition of core cancer aggression pathways, including those associated with basal tumor and pluripotency phenotypes and with epithelial–mesenchymal transition (EMT) programs. While a subset of BORG-associated pathways was present in high BORG-expressing tumors across all breast cancer subtypes, many were specific to tumors categorized as triple-negative breast cancers. Finally, we show that genes induced by heterologous expression of BORG in murine models of TNBC both in vitro and in vivo strongly overlap with those associated with high BORG expression levels in human TNBC tumors. Conclusion: Our findings implicate human BORG as a novel driver of the highly aggressive basal TNBC tumor phenotype. [ABSTRACT FROM AUTHOR]

Simple Summary: Drugs work by binding to a specific 3D structure on a protein. Drug discovery has historically been driven by prior knowledge of function, either of a protein or chemical. This knowledge of function then drives investigations to probe chemical/protein interactions. We undertook a different approach. We first identified unique 3D structures, agnostic of function, and investigated whether they could lead us to innovative therapeutics. Using a synchrotron-based X-ray source, we first determined high-resolution structures of hundreds of proteins. With a supercomputer running analytical programs created by us, we identified novel 3D structures and screened for chemicals binding them. We then tested their ability to inhibit cancer growth without damaging normal cells. We identified a potent inhibitor of a deadly cancer, melanoma. It was not toxic to normal cells even at 2100-fold higher doses. It worked by inducing anoikis, a fundamental process of known importance for cancer. Therapeutics that selectively induce anoikis are needed. In summary, we demonstrate the power of using a 3D protein structure as the starting point to discover new biology and drugs. Drug discovery historically starts with an established function, either that of compounds or proteins. This can hamper discovery of novel therapeutics. As structure determines function, we hypothesized that unique 3D protein structures constitute primary data that can inform novel discovery. Using a computationally intensive physics-based analytical platform operating at supercomputing speeds, we probed a high-resolution protein X-ray crystallographic library developed by us. For each of the eight identified novel 3D structures, we analyzed binding of sixty million compounds. Top-ranking compounds were acquired and screened for efficacy against breast, prostate, colon, or lung cancer, and for toxicity on normal human bone marrow stem cells, both using eight-day colony formation assays. Effective and non-toxic compounds segregated to two pockets. One compound, Dxr2-017, exhibited selective anti-melanoma activity in the NCI-60 cell line screen. In eight-day assays, Dxr2-017 had an IC50 of 12 nM against melanoma cells, while concentrations over 2100-fold higher had minimal stem cell toxicity. Dxr2-017 induced anoikis, a unique form of programmed cell death in need of targeted therapeutics. Our findings demonstrate proof-of-concept that protein structures represent high-value primary data to support the discovery of novel acting therapeutics. This approach is widely applicable. [ABSTRACT FROM AUTHOR]

Simple Summary: Stem cells are unique cell types in our body that play a key role in organ development and repair. Various inflammatory molecules act as critical regulators of stem cell activity. The dysregulation of inflammation and stem cell signaling pathways leads to a variety of diseases, including cancer. This review summarizes the role of inflammatory signals in regulating stem cell function within the gastrointestinal (GI) tract. We further discuss the studies highlighting the role of stem cells in the initiation and progression of cancers of the GI tract. We also report on various studies that assess the prognostic and therapeutic utility of cancer stem cells and their molecular markers in GI cancers. Stem cells are critical for the development and homeostasis of the gastrointestinal (GI) tract. Inflammatory molecules are known to regulate the activity of stem cells. A comprehensive review specifically describing the role of inflammatory molecules in the regulation of stem cells within the GI tract and in GI cancers (GICs) is not available. This review focuses on understanding the role of inflammatory molecules and stem cells in maintaining homeostasis of the GI tract. We further discuss how inflammatory conditions contribute to the transformation of stem cells into tumor-initiating cells. We also describe the molecular mechanisms of inflammation and stem cell-driven progression and metastasis of GICs. Furthermore, we report on studies describing the prognostic value of cancer stem cells and the clinical trials evaluating their therapeutic utility. This review provides a detailed overview on the role of inflammatory molecules and stem cells in maintaining GI tract homeostasis and their implications for GI-related malignancies [ABSTRACT FROM AUTHOR]

Age at exposure is a critical modifier of the risk of radiation-induced cancer. However, the effects of age on radiation-induced carcinogenesis remain poorly understood. In this study, we focused on tissue stem cells using Lgr5-eGFP-ires-CreERT2 mice to compare radiation-induced DNA damage responses between Lgr5+ and Lgr5- intestinal stem cells. Three-dimensional immunostaining analyses demonstrated that radiation induced apoptosis and the mitotic index more efficiently in adult Lgr5- stem cells than in adult Lgr5+ stem cells but not in infants, regardless of Lgr5 expression. Supporting this evidence, rapid and transient p53 activation occurred after irradiation in adult intestinal crypts but not in infants. RNA sequencing revealed greater variability in gene expression in adult Lgr5+ stem cells than in infant Lgr5+ stem cells after irradiation. Notably, the cell cycle and DNA repair pathways were more enriched in adult stem cells than in infant stem cells after irradiation. Our findings suggest that radiation-induced DNA damage responses in mouse intestinal crypts differ between infants and adults, potentially contributing to the age-dependent susceptibility to radiation carcinogenesis. [ABSTRACT FROM AUTHOR]

Adult stem cell therapy via intramyocardial injection of autologous CD34+ stem cells has been shown to improve exercise capacity and reduce angina frequency and mortality in patients with refractory angina (RA). However, the cost of such therapy is a limitation to its adoption in clinical practice. Our goal was to determine whether the less costly, less invasive, and widely accessible, FDA-approved alternative treatment for RA patients, known as enhanced external counterpulsation (EECP), mobilizes endogenous CD34+ stem cells and whether such mobilization is associated with the clinical benefits seen with intramyocardial injection. We monitored changes in circulating levels of CD34+/CD133+ and CD34+/KDR+ cells in RA patients undergoing EECP therapy and in a comparator cohort of RA patients undergoing an exercise regimen known as cardiac rehabilitation. Changes in exercise capacity in both cohorts were monitored by measuring treadmill times (TT), double product (DP) scores, and Canadian Cardiovascular Society (CCS) angina scores between pre- and post-treatment treadmill stress tests. Circulating levels of CD34+/CD133+ cells increased in patients undergoing EECP and were significant (β = −2.38, p = 0.012) predictors of improved exercise capacity in these patients. CD34+/CD133+ cells isolated from RA patients could differentiate into endothelial cells, and their numbers increased during EECP therapy. Our results support the hypothesis that mobilized CD34+/CD133+ cells repair vascular damage and increase collateral circulation in RA patients. They further support clinical interventions that can mobilize adult CD34+ stem cells as therapy for patients with RA and other vascular diseases. [ABSTRACT FROM AUTHOR]

The primary objective of omics in space with focus on the human organism is to characterize and quantify biological factors that alter structure, morphology, function, and dynamics of human cells exposed to microgravity. This review discusses exciting data regarding genomics, transcriptomics, epigenomics, metabolomics, and proteomics of human cells and individuals in space, as well as cells cultured under simulated microgravity. The NASA Twins Study significantly heightened interest in applying omics technologies and bioinformatics in space and terrestrial environments. Here, we present the available publications in this field with a focus on specialized cells and stem cells exposed to real and simulated microgravity conditions. We summarize current knowledge of the following topics: (i) omics studies on stem cells, (ii) omics studies on benign specialized different cell types of the human organism, (iii) discussing the advantages of this knowledge for space commercialization and exploration, and (iv) summarizing the emerging opportunities for translational regenerative medicine for space travelers and human patients on Earth. [ABSTRACT FROM AUTHOR]

Previously, we described the mechanisms of development of autoimmune encephalomyelitis (EAE) in 3-month-old C57BL/6, Th, and 2D2 mice. The faster and more profound spontaneous development of EAE with the achievement of deeper pathology occurs in hybrid 2D2/Th mice. Here, the cellular and immunological analysis of EAE development in 2D2/Th mice was carried out. In Th, 2D2, and 2D2/Th mice, the development of EAE is associated with a change in the differentiation profile of hemopoietic bone marrow stem cells, which, in 2D2/Th, differs significantly from 2D2 and Th mice. Hybrid 2D2/Th mice demonstrate a significant difference in these changes in all strains of mice, leading to the production of antibodies with catalytic activities, known as abzymes, against self-antigens: myelin oligodendrocyte glycoprotein (MOG), DNA, myelin basic protein (MBP), and five histones (H1–H4) hydrolyze these antigens. There is also the proliferation of B and T lymphocytes in different organs (blood, bone marrow, thymus, spleen, lymph nodes). The patterns of changes in the concentration of antibodies and the relative activity of abzymes during the spontaneous development of EAE in the hydrolysis of these immunogens are significantly or radically different for the three lines of mice: Th, 2D2, and 2D2/Th. Several factors may play an essential role in the acceleration of EAE in 2D2/Th mice. The treatment of mice with MOG accelerates the development of EAE pathology. In the initial period of EAE development, the concentration of anti-MOG antibodies in 2D2/Th is significantly higher than in Th (29.1-fold) and 2D2 (11.7-fold). As shown earlier, antibodies with DNase activity penetrate cellular and nuclear membranes and activate cell apoptosis, stimulating autoimmune processes. In the initial period of EAE development, the concentration of anti-DNA antibodies in 2D2/Th hybrids is higher than in Th (4.6-fold) and 2D2 (25.7-fold); only 2D2/Th mice exhibited a very strong 10.6-fold increase in the DNase activity of IgGs during the development of EAE. Free histones in the blood are cytotoxic and stimulate the development of autoimmune diseases. Only in 2D2/Th mice, during different periods of EAE development, was a sharp increase in the anti-antibody activity in the hydrolysis of some histones observed. [ABSTRACT FROM AUTHOR]

The basal cell maintains the airway's respiratory epithelium as the putative resident stem cell. Basal cells are known to self-renew and differentiate into airway ciliated and secretory cells. However, it is not clear if every basal cell functions as a stem cell. To address functional heterogeneity amongst the basal cell population, we developed a novel monoclonal antibody, HLO1-6H5, that identifies a subset of KRT5+ (cytokeratin 5) basal cells. We used HLO1-6H5 and other known basal cell-reactive reagents to isolate viable airway subsets from primary human airway epithelium by Fluorescence Activated Cell Sorting. Isolated primary cell subsets were assessed for the stem cell capabilities of self-renewal and differentiation in the bronchosphere assay, which revealed that bipotent stem cells were, at minimum 3-fold enriched in the HLO1-6H5+ cell subset. Crosslinking-mass spectrometry identified the HLO1-6H5 target as a glycosylated TFRC/CD71 (transferrin receptor) proteoform. The HLO1-6H5 antibody provides a valuable new tool for identifying and isolating a subset of primary human airway basal cells that are substantially enriched for bipotent stem/progenitor cells and reveals TFRC as a defining surface marker for this novel cell subset. [ABSTRACT FROM AUTHOR]