Glial ferritin maintains neural stem cells via transporting iron required for self-renewal in Drosophila.

Stem cell niche is critical for regulating the behavior of stem cells. Drosophila neural stem cells (Neuroblasts, NBs) are encased by glial niche cells closely, but it still remains unclear whether glial niche cells can regulate the self-renewal and differentiation of NBs. Here, we show that ferritin produced by glia, cooperates with Zip13 to transport iron into NBs for the energy production, which is essential to the self-renewal and proliferation of NBs. The knockdown of glial ferritin encoding genes causes energy shortage in NBs via downregulating aconitase activity and NAD+ level, which leads to the low proliferation and premature differentiation of NBs mediated by Prospero entering nuclei. More importantly, ferritin is a potential target for tumor suppression. In addition, the level of glial ferritin production is affected by the status of NBs, establishing a bicellular iron homeostasis. In this study, we demonstrate that glial cells are indispensable to maintain the self-renewal of NBs, unveiling a novel role of the NB glial niche during brain development.

Iron is an essential nutrient for almost all living organisms. For example, iron contributes to the replication of DNA, the generation of energy inside cells, and the transport of oxygen around the body. Iron deficiency is the most common of all nutrient deficiencies, affecting over 40% of children worldwide. This can lead to anemia and also impair how the brain and nervous system develop, potentially resulting in long-lasting cognitive damage, even after the deficiency has been treated. It is poorly understood how iron contributes to the development of the brain and nervous system. In particular, whether and how it supports nerve stem cells (or NSCs for short) which give rise to the various neural types in the mature brain. To investigate, Ma et al. experimentally reduced the levels of ferritin (a protein which stores iron) in the developing brains of fruit fly larvae. This reduction in ferritin led to lower numbers of NSCs and a smaller brain. Unexpectedly, this effect was largest when ferritin levels were reduced in glial cells which support and send signals to NSCs, rather than in the stem cells themselves. Ma et al. then used fluorescence microscopy to confirm that glial cells make and contain a lot of ferritin which can be transported to NSCs. Adding iron supplements to the diet of flies lacking ferritin did not lead to normal numbers of stem cells in the brains of the developing fruit flies, whereas adding compounds that reduce the amount of iron led to lower numbers of stem cells. Together, this suggests that ferritin transports iron from glial cells to the NSCs. Without ferritin and iron, the NSCs could not produce enough energy to divide and make new stem cells. This caused the NSCs to lose the characteristics of stem cells and prematurely turn into other types of neurons or glial cells. Together, these findings show that when iron cannot move from glial cells to NSCs this leads to defects in brain development. Future experiments will have to test whether a similar transport of iron from supporting cells to NSCs also occurs in the developing brains of mammals, and whether this mechanism applies to stem cells in other parts of the body.

PTN from Leydig cells activates SDC2 and modulates human spermatogonial stem cell proliferation and survival via GFRA1.

BACKGROUND: Spermatogonial stem cells (SSCs) are essential for the maintenance and initiation of male spermatogenesis. Despite the advances in understanding SSC biology in mouse models, the mechanisms underlying human SSC development remain elusive. RESULTS: Here, we analyzed the signaling pathways involved in SSC regulation by testicular somatic cells using single-cell sequencing data (GEO datasets: GSE149512 and GSE112013) and identified that Leydig cells communicate with SSCs through pleiotrophin (PTN) and its receptor syndecan-2 (SDC2). Immunofluorescence, STRING prediction, and protein immunoprecipitation assays confirmed the interaction between PTN and SDC2 in spermatogonia, but their co-localization was observed only in approximately 50% of the cells. The knockdown of SDC2 in human SSC lines impaired cell proliferation, DNA synthesis, and the expression of PLZF, a key marker for SSC self-renewal. Transcriptome analysis revealed that SDC2 knockdown downregulated the expression of GFRA1, a crucial factor for SSC proliferation and self-renewal, and inhibited the HIF-1 signaling pathway. Exogenous PTN rescued the proliferation and GFRA1 expression in SDC2 knockdown SSC lines. In addition, we found downregulation of PTN and SDC2 as well as altered localization in non-obstructive azoospermia (NOA) patients, suggesting that downregulation of PTN and SDC2 may be associated with impaired spermatogenesis. CONCLUSIONS: Our results uncover a novel mechanism of human SSC regulation by the testicular microenvironment and suggest a potential therapeutic target for male infertility.

Casticin suppresses self-renewal related stemness via miR-342-3p-mediated FoxM1 downregulation in cervical cancer cells.

BACKGROUND: Casticin (CAS), a natural flavonoid found in Viticis Fructus, Viticis Cannabifoliae Fructus, and Semen Euphorbiae, shows anti-inflammatory activity and efficacy against various cancers. However, its effect on stemness associated with self-renewal in cervical cancer (CC) cells remains unclear, as well as the underlying mechanism. PURPOSE: The primary objective of this study was to examine the effect of CAS on CC stemness and to explore the underpinning regulatory mechanism. METHODS: HeLa cells underwent treatment with varying concentrations of CAS (0, 10, 30, 100 nM). To evaluate the impacts of CAS on CC stemness and tumorigenicity, sphere- and colony-formation assays and a xenograft model were employed. The study involved screening for changes in miRNAs and their target genes. The miRNA array identified an upregulation in miRNAs, whereas the mRNA array detected a downregulation of specific target genes. The latter genes were found to regulate stem cell-related genes through miR-342-3p in HeLa cells administered CAS. Next, whether miR-342-3p directly targets FOXM1 when upregulated by CAS was assessed by the luciferase reporter assay. qRT-PCR was performed to analyze miR-342-3p expression. Additionally, immunoblotting was conducted to assess the protein amounts of FoxM1 and stemness-related factors (CD133, CD49f, Nanog, and Sox2). Function rescue experiments were conducted to determine the mechanism of CAS in stemness regulation. These experiments involved utilizing a miR-342-3p inhibitor and overexpressing FOXM1 in HeLa cells. RESULTS: CAS decreased in vitro stemness, suppressing sphere- and colony-formation capabilities of CC. It also dose-dependently downregulated the expression of stemness-associated proteins, including CD133, CD49f, Nanog, and Sox2. Moreover, CAS inhibited in vivo carcinogenesis, remarkably reducing tumor growth in mice bearing HeLa cell xenografts. Analysis revealed downregulated FOXM1 expression in HeLa cells treated with CAS. In the luciferase reporter assay, miR-342-3p was found to directly target FOXM1 in CAS-treated HeLa cells. Additionally, miR-342-3p inhibitor transfection successfully rescued CAS' suppressive impact on stemness. Furthermore, overexpression of FOXM1 did not induce changes in miR-342-3p expression. However, it effectively rescued CAS' suppressive effects on stemness. Moreover, CAS also inhibited stemness, upregulated miR-342-3p, and lowered FOXM1 expression in the SiHa cell line. CONCLUSION: CAS suppresses self-renewal-associated stemness by targeting FOXM1 via miR-342-3p upregulation. These findings suggest CAS is promising as a novel therapeutic candidate in CC.

LncRNA ACVR2B-as1 interacts with ALDOA to regulate the self-renewal and apoptosis of human spermatogonial stem cells by controlling glycolysis activity.

Human spermatogonial stem cells (SSCs) have significant applications in reproductive medicine and regenerative medicine because of their great plasticity. Nevertheless, it remains unknown about the functions and mechanisms of long non-coding RNA (LncRNA) in regulating the fate determinations of human SSCs. Here we have demonstrated that LncRNA ACVR2B-as1 (activin A receptor type 2B antisense RNA 1) controls the self-renewal and apoptosis of human SSCs by interaction with ALDOA via glycolysis activity. LncRNA ACVR2B-as1 is highly expressed in human SSCs. LncRNA ACVR2B-as1 silencing suppresses the proliferation and DNA synthesis and enhances the apoptosis of human SSCs. Mechanistically, our ChIRP-MS and RIP assays revealed that ACVR2B-as1 interacted with ALDOA in human SSCs. High expression of ACVR2B-as1 enhanced the proliferation, DNA synthesis, and glycolysis of human SSCs but inhibited their apoptosis through up-regulation of ALDOA. Importantly, overexpression of ALDOA counteracted the effect of ACVR2B-as1 knockdown on the aforementioned biological processes. Collectively, these results indicate that ACVR2B-as1 interacts with ALDOA to control the self-renewal and apoptosis of human SSCs by enhancing glycolysis activity. This study is of great significance because it sheds a novel insight into molecular mechanisms underlying the fate decisions of human SSCs and it may offer innovative approaches to address the etiology of male infertility.

Microenvironment of spermatogonial stem cells: a key factor in the regulation of spermatogenesis.

Spermatogonial stem cells (SSCs) play a crucial role in the male reproductive system, responsible for maintaining continuous spermatogenesis. The microenvironment or niche of SSCs is a key factor in regulating their self-renewal, differentiation and spermatogenesis. This microenvironment consists of multiple cell types, extracellular matrix, growth factors, hormones and other molecular signals that interact to form a complex regulatory network. This review aims to provide an overview of the main components of the SSCs microenvironment, explore how they regulate the fate decisions of SSCs, and discuss the potential impact of microenvironmental abnormalities on male reproductive health.

Connexin 25 maintains self-renewal and functions of airway basal cells for airway regeneration.

BACKGROUND: The formation of stem cell clones enables close contact of stem cells inside. The gap junctions in such clone spheres establish a microenvironment that allows frequent intercellular communication to maintain self-renewal and functions of stem cells. Nevertheless, the essential gap junction protein for molecular signaling in clones is poorly known. METHODS: Primary human airway basal cells (hBCs) were isolated from brushing samples through bronchoscopy and then cultured. A tightly focused femtosecond laser was used to excite the local Ca2+ in an individual cell to initiate an internal Ca2+ wave in a clone to screen gap junction proteins. Immunoflourescence staining and clonogenicity assay were used to evaluate self-renewal and functions. RNA and protein levels were assessed by PCR and Western blot. Air-liquid interface assay was conducted to evaluate the differentiation potential. A Naphthalene injury mouse model was used to assess the regeneration potential. RESULTS: Herein, we identify Connexin 25 (Cx25) dominates intercellular Ca2+ communications in clones of hBCs in vitro to maintain the self-renewal and pluripotency of them. The self-renewal and in vitro differentiation functions and in vivo regeneration potential of hBCs in an airway damage model are both regulated by Cx25. The abnormal expression of Cx25 is validated in several diseases including IPF, Covid-19 and bronchiectasis. CONCLUSION: Cx25 is essential for hBC clones in maintaining self-renewal and functions of hBCs via gap junctions.

Potential Mechanism and Perspectives of Mesenchymal Stem Cell Therapy for Ischemic Stroke: A Review.

Mesenchymal stem cells (MSCs), as a stem cell type with multiple differentiation potentials and immune regulatory abilities, have shown broad prospects in the treatment of ischemic stroke in recent years. The main characteristics of MSCs include their self-renewal ability, differentiation potential for different types of cells, and the ability to secrete various bioactive factors such as cytokines, chemokines, and growth factors, which play a key role in tissue repair and regeneration. In the treatment of ischemic stroke, MSCs exert therapeutic effects through various mechanisms, including promoting vascular regeneration of damaged brain tissue, reducing inflammatory responses, and protecting neurons from damage caused by apoptosis. Research have shown that MSCs can promote the repair of ischemic areas by releasing neurotrophic factors and angiogenic factors, while inhibiting immune responses triggered by ischemia, thereby improving neurological function. With the in-depth study of its biological mechanism, MSCs have gradually shown good safety and effectiveness in clinical applications. Therefore, fully exploring and utilizing the potential of MSCs in the treatment of ischemic stroke may provide new ideas and solutions for future neural repair and regenerative medicine.

Autophagy accompanying the developmental process of male germline stem cells.

Germline stem cells are a crucial type of stem cell that can stably pass on genetic information to the next generation, providing the necessary foundation for the reproduction and survival of organisms. Male mammalian germline stem cells are unique cell types that include primordial germ cells and spermatogonial stem cells. They can differentiate into germ cells, such as sperm and eggs, thereby facilitating offspring reproduction. In addition, they continuously generate stem cells through self-renewal mechanisms to support the normal function of the reproductive system. Autophagy involves the use of lysosomes to degrade proteins and organelles that are regulated by relevant genes. This process plays an important role in maintaining the homeostasis of germline stem cells and the synthesis, degradation, and recycling of germline stem cell products. Recently, the developmental regulatory mechanism of germline stem cells has been further elucidated, and autophagy has been shown to be involved in the regulation of self-renewal and differentiation of germline stem cells. In this review, we introduce autophagy accompanying the development of germline stem cells, focusing on the autophagy process accompanying the development of male spermatogonial stem cells and the roles of related genes and proteins. We also briefly outline the effects of autophagy dysfunction on germline stem cells and reproduction.

A novel study on CXXC5: unraveling its regulatory mechanisms in hematopoietic stem cell biology through proteomics and gene editing.

BACKGROUND: This study investigates the role of CXXC5 in the self-renewal and differentiation of hematopoietic stem cells (HSCs) within the bone marrow microenvironment, utilizing advanced methodologies such as single-cell RNA sequencing (scRNA-seq), CRISPR-Cas9, and proteomic analysis. METHODS: We employed flow cytometry to isolate HSCs from bone marrow samples, followed by scRNA-seq analysis using the 10x Genomics platform to examine cell clustering and CXXC5 expression patterns. CRISPR-Cas9 and lentiviral vectors facilitated the knockout and overexpression of CXXC5 in HSCs. The impact on HSCs was assessed through qRT-PCR, Western blot, CCK-8, CFU, and LTC-IC assays, alongside flow cytometry to measure apoptosis and cell proportions. A mouse model was also used to evaluate the effects of CXXC5 manipulation on HSC engraftment and survival rates. RESULTS: Our findings highlight the diversity of cell clustering and the significant role of CXXC5 in HSC regulation. Knockout experiments showed reduced proliferation and accelerated differentiation, whereas overexpression led to enhanced proliferation and delayed differentiation. Proteomic analysis identified key biological processes influenced by CXXC5, including cell proliferation, differentiation, and apoptosis. In vivo results demonstrated that CXXC5 silencing impaired HSC engraftment in a bone marrow transplantation model. CONCLUSION: CXXC5 is crucial for the regulation of HSC self-renewal and differentiation in the bone marrow microenvironment. Its manipulation presents a novel approach for enhancing HSC function and provides a potential therapeutic target for hematological diseases.

Therapeutic potential of tLyp-1-EV-shCTCF in inhibiting liver cancer stem cell self-renewal and immune escape via SALL3 modulation in hepatocellular carcinoma.

The progression of hepatocellular carcinoma (HCC) is influenced by disrupted metabolic processes, presenting challenges in prognostic outcomes. Hepatocellular carcinoma (HCC), a leading cause of cancer-related mortality, is closely associated with metabolic reprogramming and stem cell-like properties in liver cancer stem cells (LCSCs). This study explored the potential molecular mechanisms by which tLyP-1-modified extracellular vesicles (EVs) delivering CTCF shRNA (tLyp-1-EV-shCTCF) regulate mitochondrial DNA methylation-induced glycolytic metabolic reprogramming and LCSC self-renewal. Through a series of methods, including Western blot, nanoparticle tracking analysis, and immunofluorescence, we demonstrated the successful delivery and internalization of tLyp-1-EV in HCC cells. Our results identified SALL3 as a critical factor underexpressed in HCC and LCSCs, while CTCF was overexpressed. Overexpression of SALL3 inhibited LCSC self-renewal and immune evasion by blocking the CTCF-DNMT3A interaction, thus repressing DNMT3A methyltransferase activity and subsequent mitochondrial DNA methylation-mediated glycolytic metabolic reprogramming. In vivo experiments further supported these findings, showing that tLyp-1-EV-shCTCF treatment significantly reduced tumor growth by upregulating SALL3 expression, thereby inhibiting glycolytic metabolic reprogramming and enhancing the immune response against HCC cells. This study provides novel insights into the role of SALL3 and mitochondrial DNA methylation in HCC progression, offering potential therapeutic targets for combating HCC and its stem cell-like properties.

Cxcl10 and Cxcr3 regulate self-renewal and differentiation of hematopoietic stem cells.

BACKGROUND: The function of hematopoietic stem cells (HSC) is regulated by HSC internal signaling pathways and their microenvironment. Chemokines and chemokine ligands play important roles in the regulation of HSC function. Yet, their functions in HSC are not fully understood. METHODS: We established Cxcr3 and Cxcl10 knockout mouse models (Cxcr3-/- and Cxcl10-/-) to analyze the roles of Cxcr3 or Cxcl10 in regulating HSC function. The cell cycle distribution of LT-HSC was assessed via flow cytometry. Cxcr3-/- and Cxcl10-/- stem/progenitor cells showed reduced self-renewal capacity as measured in serial transplantation assays. To study the effects of Cxcr3 or Cxcl10 deficient bone marrow microenvironment, we transplanted CD45.1 donor cells into Cxcr3-/-or Cxcl10-/- recipient mice (CD45.2) and examined donor-contributed hematopoiesis. RESULTS: Deficiency of Cxcl10 and its receptor Cxcr3 led to decreased BM cellularity in mice, with a significantly increased proportion of LT-HSC. Cxcl10-/- stem/progenitor cells showed reduced self-renewal capacity in the secondary transplantation assay. Notably, Cxcl10-/- donor-derived cells preferentially differentiated into B lymphocytes, with skewed myeloid differentiation ability. Meanwhile, Cxcr3-deficient HSCs demonstrated a reconstitution disadvantage in secondary transplantation, but the lineage bias was not significant. Interestingly, the absence of Cxcl10 or Cxcr3 in bone marrow microenvironment did not affect HSC function. CONCLUSIONS: The Cxcl10 and Cxcr3 regulate the function of HSC, including self-renewal and differentiation, adding to the understanding of the roles of chemokines in the regulation of HSC function.

Decoding Clonal Hematopoiesis: Emerging Themes and Novel Mechanistic Insights.

Clonal hematopoiesis (CH), the relative expansion of mutant clones, is derived from hematopoietic stem cells (HSCs) with acquired somatic or cytogenetic alterations that improve cellular fitness. Individuals with CH have a higher risk for hematological and non-hematological diseases, such as cardiovascular disease, and have an overall higher mortality rate. Originally thought to be restricted to a small fraction of elderly people, recent advances in single-cell sequencing and bioinformatics have revealed that CH with multiple expanded mutant clones is universal in the elderly population. Just a few years ago, phylogenetic reconstruction across the human lifespan and novel sensitive sequencing techniques showed that CH can start earlier in life, decades before it was thought possible. These studies also suggest that environmental factors acting through aberrant inflammation might be a common theme promoting clonal expansion and disease progression. However, numerous aspects of this phenomenon remain to be elucidated and the precise mechanisms, context-specific drivers, and pathways of clonal expansion remain to be established. Here, we review our current understanding of the cellular mechanisms driving CH and specifically focus on how pro-inflammatory factors affect normal and mutant HSC fates to promote clonal selection.

Propagating pluripotency - The conundrum of self-renewal.

The discovery of mouse embryonic stem cells in 1981 transformed research in mammalian developmental biology and functional genomics. The subsequent generation of human pluripotent stem cells (PSCs) and the development of molecular reprogramming have opened unheralded avenues for drug discovery and cell replacement therapy. Here, I review the history of PSCs from the perspective that long-term self-renewal is a product of the in vitro signaling environment, rather than an intrinsic feature of embryos. I discuss the relationship between pluripotent states captured in vitro to stages of epiblast in the embryo and suggest key considerations for evaluation of PSCs. A remaining fundamental challenge is to determine whether naïve pluripotency can be propagated from the broad range of mammals by exploiting common principles in gene regulatory architecture.

Establishment of porcine embryonic stem cells in simplified serum free media and feeder free expansion.

BACKGROUND: The establishment of stable porcine embryonic stem cells (pESCs) can contribute to basic and biomedical research, including comparative developmental biology, as well as assessing the safety of stem cell-based therapies. Despite these advantages, most pESCs obtained from in vitro blastocysts require complex media and feeder layers, making routine use, genetic modification, and differentiation into specific cell types difficult. We aimed to establish pESCs with a single cell-passage ability, high proliferative potency, and stable in long-term culture from in vitro-derived blastocysts using a simplified serum-free medium. METHODS: We evaluated the establishment efficiency of pESCs from in vitro blastocysts using various basal media (DMEM/F10 (1:1), DMEM/F12, and a-MEM) and factors (FGF2, IWR-1, CHIR99021, and WH-4-023). The pluripotency and self-renewal capacity of the established pESCs were analyzed under feeder or feeder-free conditions. Ultimately, we developed a simplified culture medium (FIW) composed of FGF2, IWR-1, and WH-4-023 under serum-free conditions. RESULTS: The pESC-FIW lines were capable of single-cell passaging with short cell doubling times and expressed the pluripotency markers POU5F1, SOX2, and NANOG, as well as cell surface markers SSEA1, SSEA4, and TRA-1-60. pESC-FIW showed a stable proliferation rate and normal karyotype, even after 50 passages. Transcriptome analysis revealed that pESC-FIW were similar to reported pESC maintained in complex media and showed gastrulating epiblast cell characteristics. pESC-FIW were maintained for multiple passages under feeder-free conditions on fibronectin-coated plates using mTeSR™, a commercial medium used for feeder-free culture, exhibiting characteristics similar to those observed under feeder conditions. CONCLUSIONS: These results indicated that inhibition of WNT and SRC was sufficient to establish pESCs capable of single-cell passaging and feeder-free expansion under serum-free conditions. The easy maintenance of pESCs facilitates their application in gene editing technology for agriculture and biomedicine, as well as lineage commitment studies.

The proliferation and differentiation of spermatogonial stem cells in the frist wave of spermatogenesis in rats with Trib3 gene knockout.

This study explores the effects of Trib3 gene knockout on adult male rat spermatogenesis. Using CRISPR/Cas9, we knocked out the Trib3 gene in Wistar rats. Results indicate altered expression of PLZF, ID4, and c-KIT in knockout rats, suggesting impaired spermatogonial stem cell proliferation and differentiation. Histological analysis reveals reduced seminiferous tubule area and decreased spermatocyte numbers. Mating experiments demonstrate reduced offspring rates after the second self-mating in knockout rats. SYCP3, a meiosis marker, shows elevated expression in knockout rat testes at 14 days postpartum, suggesting an impact on reproductive processes. ELISA results indicate decreased testosterone, FSH, and FGF9 levels in knockout rat testicular tissues. In conclusion, Trib3 gene deletion may impede spermatogonial self-renewal and promote differentiation through the FSH-FGF9- c-KIT interaction and p38MAPK pathway, affecting reproductive capacity. These findings contribute to understanding the molecular mechanisms regulating spermatogenesis.

Unraveling the role of long non-coding RNAs in therapeutic resistance in acute myeloid leukemia: New prospects & challenges.

Acute Myeloid Leukemia (AML) is a fatal hematological disease characterized by the unchecked proliferation of immature myeloid blasts in different tissues developed by various mutations in hematopoiesis. Despite intense chemotherapeutic regimens, patients often experience poor outcomes, leading to substandard remission rates. In recent years, long non-coding RNAs (lncRNAs) have increasingly become important prognostic and therapeutic hotspots, due to their contributions to dysregulating many functional epigenetic, transcriptional, and post-translational mechanisms leading to alterations in cell expressions, resulting in increased chemoresistance and reduced apoptosis in leukemic cells. Through this review, I highlight and discuss the latest advances in understanding the major mechanisms through which lncRNAs confer therapy resistance in AML. In addition, I also provide perspective on the current strategies to target lncRNA expressions. A better knowledge of the critical role that lncRNAs play in controlling treatment outcomes in AML will help improve existing medications and devise new ones.

Stimulating effect of nanocurcumin and crocin on proliferation and pluripotency of bone marrow-derived mesenchymal stem cells.

Objectives: Enhancement of proliferation, pluripotency, and self-renewal capacity as the unique features of MSCs can improve their therapeutic potential to regenerate tissues. In this context, crocin and curcumin, carotenoid compounds with outstanding medicinal properties, could be promising for cell protection and growth. This study aimed to evaluate the impact of nanocurcumin and crocin on BM-MSCs proliferation and pluripotency in vitro. Materials and Methods: BM-MSC were isolated from the iliac crest of SCI patients who were candidates for stem cell therapy. The effect of crocin and nanocurcumin on MSC proliferation was evaluated using MTT and PDT assay. The percentage of apoptotic MSCs was measured by flow cytometry. Furthermore, mRNA and protein expression of OCT4 and SOX2 as the proliferation and self-renewal related genes were quantified by real-time PCR and western blotting, respectively. Results: Our findings demonstrated that only low concentrations of nanocurcumin (0.3 and 0.7 µM) and crocin (2.5 5 µM) significantly affected MSCs proliferation and protected them from apoptosis. Also, crocin and nanocurcumin at low doses caused an elevation in the mRNA and protein expression levels of OCT4 and SOX2 genes. In contrast, high concentrations decreased the survival of MSCs and led to increased apoptosis compared with the untreated group. Conclusion: Our results suggest that using nanocurcumin and crocin separately in culturing MSCs can be considered proliferative agents to prepare the more advantageous tool for cell therapies. However, more in vitro and preclinical research is needed in this area.

A novel chemical genetic approach reveals paralog-specific role of ERK1/2 in mouse embryonic stem cell fate control.

Introduction: Mouse embryonic stem cell (ESC) self-renewal can be maintained through dual inhibition of GSK3 and MEK kinases. MEK has two highly homologous downstream kinases, extracellular signal-regulated kinase 1 and 2 (ERK1/2). However, the exact roles of ERK1/2 in mouse ESC self-renewal and differentiation remain unclear. Methods: We selectively deleted or inhibited ERK1, ERK2, or both using genetic and chemical genetic approaches combined with small molecule inhibitors. The effects of ERK paralog-specific inhibition on mouse ESC self-renewal and differentiation were then assessed. Results: ERK1/2 were found to be dispensable for mouse ESC survival and self-renewal. The inhibition of both ERK paralogs, in conjunction with GSK3 inhibition, was sufficient to maintain mouse ESC self-renewal. In contrast, selective deletion or inhibition of only one ERK paralog did not mimic the effect of MEK inhibition in promoting mouse ESC self-renewal. Regarding ESC differentiation, inhibition of ERK1/2 prevented mesendoderm differentiation. Additionally, selective inhibition of ERK1, but not ERK2, promoted mesendoderm differentiation. Discussion: These findings suggest that ERK1 and ERK2 have both overlapping and distinct roles in regulating ESC self-renewal and differentiation. This study provides new insights into the molecular mechanisms of ERK1/2 in governing ESC maintenance and lineage commitment, potentially informing future strategies for controlling stem cell fate in research and therapeutic applications.

Metabolism and HSC fate: what NADPH is made for.

Mitochondrial metabolism plays a central role in the regulation of hematopoietic stem cell (HSC) biology. Mitochondrial fatty acid oxidation (FAO) is pivotal in controlling HSC self-renewal and differentiation. Herein, we discuss recent evidence suggesting that NADPH generated in the mitochondria can influence the fate of HSCs. Although NADPH has multiple functions, HSCs show high levels of NADPH that are preferentially used for cholesterol biosynthesis. Endogenous cholesterol supports the biogenesis of extracellular vesicles (EVs), which are essential for maintaining HSC properties. We also highlight the significance of EVs in hematopoiesis through autocrine signaling. Elucidating the mitochondrial NADPH-cholesterol axis as part of the metabolic requirements of healthy HSCs will facilitate the development of new therapies for hematological disorders.

CD44/PD-L1-mediated networks in drug resistance and immune evasion of breast cancer stem cells: Promising targets of natural compounds.

Cancer stem cells (CSCs) significantly interfere with immunotherapy, leading to challenges such as low response rates and acquired resistance. PD-L1 expression is associated with the CSC population's overexpression of CD44. Mounting evidence suggests that the breast cancer stem cell (BCSC) marker CD44 and the immune checkpoint PD-L1 contribute to treatment failure through their networks. Natural compounds can overcome therapy resistance in breast cancer by targeting mechanisms underlying resistance in BCSCs. This review provides an updated insight into the CD44 and PD-L1 networks of BCSCs in mediating metastasis and immune evasion. The review critically examines existing literature, providing a comprehensive understanding of the topic and emphasizing the impact of natural flavones on the signaling pathways of BCSCs. Additionally, the review discusses the potential of natural compounds in targeting CD44 and PD-L1 in breast cancer (BC). Natural compounds consistently show potential in targeting regulatory mechanisms of BCSCs, inducing loss of stemness, and promoting differentiation. They offer a promising approach for developing alternative therapeutic strategies to manage breast cancer.