Stem Cell Reviews and Reports最新文献

Research on cancer therapies has benefited from predictive tools capable of simulating treatment response and other disease characteristics in a personalized manner, in particular three-dimensional cell culture models. Such models include tumor-derived spheroids, multicellular spheroids including organotypic multicellular spheroids, and tumor-derived organoids. Additionally, organoids can be grown from various cancer cell types, such as pluripotent stem cells and induced pluripotent stem cells, progenitor cells, and adult stem cells. Although patient-derived xenografts and genetically engineered mouse models replicate human disease in vivo, organoids are less expensive, less labor intensive, and less time-consuming, all-important aspects in high-throughput settings. Like in vivo models, organoids mimic the three-dimensional structure, cellular heterogeneity, and functions of primary tissues, with the advantage of representing the normal oxygen conditions of patient organs. In this review, we summarize the use of organoids in disease modeling, drug discovery, toxicity testing, and precision oncology. We also summarize the current clinical trials using organoids.

Hematopoietic cell transplantation (HCT) is an important therapy for many hematological malignancies as well as some non-malignant diseases. Post-transplant hematopoiesis is affected by multiple factors, and the mechanisms of delayed post-transplant hematopoiesis remain poorly understood. Patients undergoing HCT often suffer from significantly reduced food intake due to complications induced by preconditioning treatments. Here, we used a dietary restriction (DR) mouse model to study the effect of post-transplant dietary reduction on hematopoiesis and hematopoietic stem cells (HSCs). We found that post-transplant DR significantly inhibited both lymphopoiesis and myelopoiesis in the primary recipient mice. However, when bone marrow cells (BMCs) from the primary recipient mice were serially transplanted into secondary and tertiary recipient mice, the HSCs derived from the primary recipient mice, which were exposed to post-transplant DR, exhibited a much higher reconstitution capacity. Transplantation experiments with purified HSCs showed that post-transplant DR greatly inhibited hematopoietic stem cell (HSC) expansion. Additionally, post-transplant DR reshaped the gut microbiotas of the recipient mice, which inhibited inflammatory responses and thus may have contributed to maintaining HSC function. Our findings may have important implications for clinical work because reduced food intake and problems with digestion and absorption are common in patients undergoing HCT.

NADPH oxidase 2 (Nox2), a superoxide-generating enzyme, is a source of reactive oxygen species (ROS) that regulate the intracellular redox state, self-renewal, and fate of hematopoietic stem/progenitor cells (HSPCs). Nox2 complex expressed on HSPCs associated with several activated cell membrane receptors increases the intracellular level of ROS. In addition, ROS are also released from mitochondria and, all together, are potent activators of intracellular pattern recognition receptor Nlrp3 inflammasome, which regulates the trafficking, proliferation, and metabolism of HSPCs. In the current study, we noticed that Nox2-deficient mice, despite the increased number of HSPCs in the bone marrow (BM), show hematopoietic defects illustrated by delayed recovery of peripheral blood (PB) hematopoietic parameters after sublethal irradiation and mobilize fewer HSPCs after administration of G-CSF and AMD3100. Moreover, Nox2-deficient HSPCs engraft poorly after transplantation into normal syngeneic recipients. To explain these defects at the molecular level, we hypothesized that Nox2-KO decreased ROS level does not efficiently activate Nlrp3 inflammasome, which plays a crucial role in regulating the trafficking of HSPCs. Herein, we report Nox2-deficient HSPCs display i) defective migration to major chemoattractant, ii) impaired intracellular activation of Nlrp3 inflammasome, and iii) a defect in membrane lipid raft (MLRs) formation that is required for a proper chemotactic response to pro-migratory factors. We conclude that Nox2-derived ROS enhances in Nlrp3 inflammasome-dependent manner HSPCs trafficking by facilitating MLRs assemble on the outer cell membranes, and defect in Nox2 expression results in impaired activation of Nlrp3 inflammasome, which affects HSPCs migration.

Pluripotent stem cells have the ability to differentiate into all cells and tissues within the human body, and as a result they are attractive resources for use in basic research, drug discovery and regenerative medicine. In order to successfully achieve this application, starting cell sources ideally require in-depth characterisation to confirm their pluripotent status and their ability to differentiate into tissues representative of the three developmental germ layers. Many different methods to assess potency are employed, each having its own distinct advantages and limitations. Some aspects of this characterisation process are not always well standardised, particularly techniques used to assess pluripotency as a function. In this article, we consider the methods used to establish cellular pluripotency and subsequently analyse characterisation data for over 1590 human pluripotent cell lines from publicly available repositories in the UK and USA. In particular, we focus on the teratoma xenograft assay, its use and protocols, demonstrating the level of variation and the frequency with which it is used. Finally, we reflect on the implications of the findings, and suggest in vitro alternatives using modern innovative technology as a way forward.

To ensure the preservation of functional hematopoietic stem cells (HSC) and committed progenitor cells (HPC) at + 4 °C in ex vivo expanded cord blood cell products during worldwide transportation and subsequent infusion-without the need for washing and cell concentration-we developed a conservation medium called Stabilizer of Expanded Cells (SEC), composed exclusively of injectable pharmacological products. The in vivo engraftment assay in immunodeficient mice was used to detect primitive HSCs before and after preservation at + 4 °C. In some experiments, a complex phenotype based on CD34, CD38, and CD133 expression was utilized for this purpose. Committed progenitors (CFU-GM, BFU-E, and CFU-Mix) were detected using methylcellulose culture colony-forming assays. Additionally, in some cases, the energetic metabolism (mitochondrial respiration) was evaluated using Seahorse technology. SEC was able to preserve the functionality of HSCs and HPCs in ex vivo expanded cell populations at + 4 °C for at least 48 h. Furthermore, SEC is also effective in fully preserving HSCs and HPCs in cytapheresis products for at least 72 h. Additionally, SEC enabled the full preservation of HSCs and HPCs for 72 h in freshly collected cord blood, maintaining a normal metabolic profile of CD34⁺ cells. The SEC medium exhibits a positive effect on the maintenance of both HSCs and HPCs at + 4 °C, regardless of their source. Therefore, SEC can be applied in cell therapy protocols based on HSCs and HPCs with a significant advantage: the product does not need to be washed and concentrated before injection into the patient.

Neonatal hypoxic-ischemic encephalopathy (HIE) is a critical condition resulting from impaired oxygen and blood flow to the brain during birth, leading to neuroinflammation, neuronal apoptosis, and long-term neurological deficits. Despite the use of therapeutic hypothermia, current treatments remain inadequate in fully preventing brain damage. Recent advances in mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) offer a novel, cell-free therapeutic approach, as these EVs can cross the blood-brain barrier (BBB) and deliver functional microRNAs (miRNAs) to modulate key pathways involved in inflammation and neuroprotection. This review examines how specific miRNAs encapsulated in MSC-EVs-including miR-21, miR-124, miR-146, and the miR-17-92 cluster-target the complex inflammatory responses that drive HIE pathology. By modulating pathways such as NF-κB, STAT3, and PI3K/Akt, these miRNAs influence neuroinflammatory processes, reduce neuronal apoptosis, and promote tissue repair. The aim is to assess the therapeutic potential of miRNA-loaded MSC-EVs in mitigating inflammation and neuronal damage, thus addressing the limitations of current therapies like therapeutic hypothermia.