Mesenchymal stem cells (MSC) represent the main stromal component of the bone marrow (BM) niche and are crucial to maintain hematopoietic tissue homeostasis. MSC exhibits extraordinary and multiple properties. In terms of expanding potential and differentiation capacity, Wharton jelly MSC (WJ-MSC), derived from the umbilical cord, was described as being greater and more performing than MSC from BM or other sources. WJ-MSC mimics the hematopoietic niche and supports hematopoietic stem cells (HSC) expansion ex vivo. This study aimed to evaluate the effects of human WJ-MSC cocultured with HSC in a B-cell differentiation protocol. Remarkably, results highlight WJ-MSC use as a preferable feeder layer to efficiently support HSC commitment toward the B-lineage. Over 11 days of HSC coculture with WJ-MSC, B-cell genes (E2A, RAG1, RAG2, etc.) expression patterns and B-cell markers (CD19, immunoglobulin chain, etc.) acquisition were evidenced. WJ-MSc were also able to unlock the B-lineage differentiation blockade of the acute lymphoblastic leukemia cell line Nalm16. This model might provide a new strategy to support ex vivo B-cell differentiation using the powerful properties of WJ-MSC. This study implements a new approach to improve understanding of B-leukemogenesis and B-cell acute lymphoblastic leukemia (B-ALL) pathophysiology.

Overcoming remyelination failure is one of the main targets in therapeutic strategies for multiple sclerosis. This process requires the differentiation of oligodendrocyte precursor cells (OPCs) to mature myelinating oligodendrocytes (OLs), a process known to be controlled by thyroid hormone, nuclear receptors, and sonic hedgehog (SHH). Retinoid X receptor gamma (RXRg) is one of the nuclear receptors acting as a positive regulator of remyelination, but little is known about its mechanisms of function. Using transcriptomic and pharmacological analysis of primary neural stem cell-derived OPCs, we show that RXRg is involved in the induction of the thyroid hormone-driven differentiation process and in refining it toward an oligodendrogenic cell fate. RXRg also emerged as an important negative modulator of SHH expression and signaling, as Shh and additional genes from this pathway were found to be strongly upregulated in Rxrg-/- OPCs. An inhibition of SHH signaling by cyclopamine or GANT61 entirely normalized the differentiation deficit of Rxrg-/- OPCs, but also myelination of newly generated Rxrg-/- OLs. Such data indicate a key role of SHH hyperactivity in the oligodendrogenesis block associated with the absence of RXRg. Importantly, hyperactivation of the SHH pathway by purmorphamine or SAG inhibited the oligodendrogenesis and myelination potential of wild-type OPCs, indicating that SHH hyperactivity can also be a sufficient factor to block OPC differentiation. These results point to RXRg as an important regulator of SHH pathway signaling and underline the need of an optimal, fine-tuning of SHH signaling to assure successful oligodendrogenesis.

Transendothelial migration (TEM), is a complex, multistep process impacted by diseases like autoimmune disorders and cancer. Deciphering aspects of the process enhances our understanding and possibilities for disease treatments. The extent to which this potential can be leveraged is often limited due to conventional assays neither accurately mimicking specific in vivo conditions like sheer stress nor visualizing the whole transmigration cascade, hence missing distinct mechanisms. Flow-based adhesion assays overcome these limitations and allow the use of various endothelial cells from different tissues with distinct properties. So far, a broader and translational assay application is hampered by potential operator-based bias/lack of standardization, as well as poor scalability due to time-consuming manual analysis. In this study, we successfully combined this assay with AI-based analysis including subsequent classification of cell-transmigration phases by a Keras/TensorFlow-based deep learning model. Trained on healthy-donor and pancreatic cancer patient-derived T cells, the model achieved a high accuracy of 91.6 % in identifying/categorizing cell transmigration, surpassing the currently accepted 80 %-threshold, therefore qualifying as a fast, standardized AI-based live-cell imaging tool. Additionally, its architecture grants highly convenient reconfiguration for various disease-model investigations. Hence, by combining an affordable and simplistic, yet potent live-cell-imaging technique with a comprehensive AI-approach, we have established a powerful tool which allows for integrating TEM-assays into various disease models.

Melanocyte stem cells (McSCs) are a crucial melanocyte reservoir within the hair follicle niche. This review provides an overview of the processes for McSC quiescence and activation. Because McSCs closely interact with hair follicle stem cells, we have focused on this interaction. Given the high prevalence of hair graying, the McSC system serves as a model for cellular aging. Here, we highlight current research on the mechanisms of hair graying.

Iron metabolism is increasingly recognized as a key player in the development and progression of various cancers. Iron is required for vital cellular processes such as energy production; however, it can also interact with reactive oxygen species to cause cellular toxicity. Consequently, a host of proteins coordinate iron homeostasis, and ferritin stands out as a promising therapeutic target due to its pivotal role in buffering cellular iron levels. This review explores the relevance of ferritin in brain cancers, shedding light on how it influences the biology of both tumor cells and cancer stem cells (CSCs), a population of tumor cells that is notable in their resistance to conventional treatment strategies. Ferritin plays a critical role in protecting against oxidative stress and boosting resistance to ferroptosis, a form of cell death often evaded by CSCs. Development of cutting-edge strategies designed to target ferritin, including ferritinophagy-inducing compounds and novel redox-based therapies that can capitalize on the iron dependency of CSCs is discussed in context. We propose that the iron addiction of brain cancer cells provides a specific susceptibility, whereby removing their iron buffering mechanism via targeting of ferritin can result in favorable treatment outcomes, including the induction of iron-dependent cell death. Future studies on the modulation of ferritin offer a ground-breaking therapeutic strategy to undermine CSC-driven tumor growth, overcome resistance to conventional therapies, and ultimately improve treatment outcomes for patients battling brain cancers.

Dental tissues development involves two distinct cell lineages: mesenchymal cells (derived from the cranial neural crest) and epithelial cells (derived from oral ectoderm and pharyngeal epithelium). Emerging evidence highlights the remarkable functional heterogeneity of cranial neural crest-derived dental mesenchymal stem cells (DMSCs), exhibiting pluripotency, self-renewal, and differentiation capacities. This heterogeneity enables a single DMSC population to generate specialized subpopulations with unique roles in teeth and periodontal tissues formation. Significant progress has been made in characterizing six major types of DMSCs and two populations of closely related cells: Tooth germ progenitor cells (TGPCs) and dental follicle stem cells (DFSCs), critical during early morphogenesis; Stem cells from human exfoliated deciduous teeth (SHEDs) and apical papilla stem cells (SCAPs), pivotal for root development; Dental pulp stem cells (DPSCs), periodontal ligament stem cells (PDLSCs), gingival mesenchymal stem cells (GMSCs) and alveolar bone mesenchymal stem cells (ABMSCs), essential for maintaining and regenerating mature dental tissues. A key breakthrough has unveiled the development and hierarchy of DMSCs by applying new techniques like single-cell RNA sequencing (scRNA-seq). To integrate insights into the development of teeth and periodontal tissues, this review synthesizes current knowledge on both developmental heterogeneity and subpopulation heterogeneity within DMSCs and related cells. These insights not only advance fundamental understanding of the developmental mechanisms of teeth and periodontal tissues, but also establish a promising framework for achieving more efficient tissue regeneration and repair engineering.

Diseases associated with obesity and metabolic dysregulation, such as diabetes and metabolic dysfunction-associated steatotic liver disease (MASLD) promote chronic low-grade inflammation, which in turn, may enhance the risk for cardiovascular disease. Emerging evidence in recent years suggests that chronicity of inflammation involves alterations in bone marrow homeostasis. Obesity-related inflammation and metabolic stress, including hyperglycemia or hyperlipidemia, may trigger rewiring of hematopoietic stem and progenitor cells (HSPCs) in the bone marrow, driving production of myeloid cells with heightened inflammatory capacity that in turn fuel and sustain chronic inflammation. This process is akin to trained immunity and may promote an inflammatory memory that links metabolic disorders to their cardiovascular complications. Clonal hematopoiesis of indeterminate potential (CHIP) is characterized by aging-related emergence of somatic mutations in hematopoietic cells that clonally expand and bear higher inflammatory potential. Importantly, a bidirectional link between CHIP and metabolic disorders as well as their cardiovascular sequelae emerges. Here, we review current concepts regarding the links between bone marrow biology and metabolic diseases and associated chronic inflammation.

Multiple myeloma (MM) is a hematological malignancy that depends on the bone marrow microenvironment, and obesity, along with intramedullary adipocytes, is associated with an increased risk of developing MM. Adipocytes protect MM cells from chemotherapy by secreting adipokines and activating autophagy, while MM cells reprogram bone marrow adipocytes. Strategies to inhibit adipocyte lipolysis have been proposed as a novel approach for treating MM. MM progression is dependent on glutamine and glucose metabolism. Lipoproteins, particularly cholesterol levels, are becoming prognostic factors in MM. However, studies on lipids lack long-term paired data. Therefore, we analyzed long-term follow-up data from 115 autograft patients at Beijing Jishuitan Hospital over the past 7.5 years to investigate the long-term changes in lipid metabolism during the course of MM and the impact of efficacy. Teaser Abstract: Is blood cholesterol a gauge for myeloma relapse? A landmark study shows that with remission, cholesterol levels promptly rise, only to markedly drop upon the cancer's recurrence-unveiling a straightforward new approach to disease tracking.

With population aging, chemotherapy-induced thrombocytopenia (CIT) is a severe complication in elderly cancer patients, yet effective preventive and therapeutic strategies remain limited. Here, we demonstrate that dietary restriction (DR) significantly mitigates 5-fluorouracil (5-FU)-induced thrombocytopenia and promotes platelet recovery in both young and aged mice. Mechanistically, DR improves mitochondrial homeostasis in hematopoietic stem and progenitor cells and enhances their hematopoietic reconstitution capacity. This preconditioning facilitates mitochondrial activation after chemotherapy, thereby promoting megakaryocytic lineage recovery. Pharmacological mitochondrial activation in ad libitum-fed mice mimics the protective effects of DR, whereas mitochondrial inhibition in DR-treated mice markedly attenuates these benefits. Clinically, cancer patients with lower pre-chemotherapy body mass index ([BMI] 18.5-22.95 kg/m2) showed a lower incidence of CIT following 5-FU treatment than those with higher BMI. Together, we show that short-term DR significantly mitigates CIT and that targeting mitochondria may represent a novel therapeutic strategy for CIT in elderly cancer patients.

Neurons derived from human pluripotent stem cells (hPSCs) are valuable models for studying brain development and developing therapies for brain disorders. Evaluating hPSC-derived neurons requires assessing their electrical activity, which can be achieved using multi-electrode arrays (MEAs) for extracellular recordings. Because each electrode channel generally detects activity from multiple neurons, resolving the activity of single neurons requires a process called spike sorting. However, currently available methods were not developed for analyzing data from hPSC-derived neurons and require complex workflows and time-consuming manual intervention. Here, we introduce a semi-automated MEA spike sorting software (SAMS) designed specifically for low-density MEA recordings of cultured neurons. SAMS outperforms commercially available automated spike sorting algorithms in terms of accuracy and greatly reduces computational and human processing time. By providing an accessible, efficient, and integrated platform for spike sorting, SAMS enhances the resolution and utility of MEA in disease modeling and drug development using hPSC-derived neurons.

The clinical application of human stem cell-derived islet organoids (SC-islets) is hindered by immaturity and ischemia-induced dysfunction post-transplantation. Hypoxia-driven angiogenesis is a common adaptation, but the metabolic fragility of SC-islet β cells leads to early functional damage and suppressed vascular endothelial growth factor A (VEGFA) expression, thereby delaying vascularization and causing graft loss. The key challenge in SC-islet transplantation is how to prevent hypoxia-induced stress and promote rapid angiogenesis. We found that excessive zinc in SC-islet β cells induces oxidative modification that inhibits AMP-activated protein kinase (AMPK) activity. Chemical inhibition of zinc transportation activates AMPK, enhances functional maturation, improves hypoxia resistance, and increases hypoxia-inducible factor 1α (HIF1A)-independent VEGFA expression to facilitate endothelial cell integration. In diabetic animal models, this approach significantly improved hypoxia resistance, accelerated angiogenesis, and enhanced glycemic control. Our findings demonstrate that chemical inhibition of zinc transportation boosts SC-islet functional competence, offering a potential strategy to advance pre-adaptation to stress in regenerative medicine.

The p.Thr369Met variant in the glucosylcerebrosidase Beta I gene (GBA1) is associated with Parkinson disease (PD) but its impact is debated. We generated and characterized human induced pluripotent stem cells from PBMCs of three PD patients: one carrying the p.Thr369Met variant in GBA1, and two carrying no GBA1 variants. These lines exhibited typical pluripotent stem cell morphology, expressed pluripotency markers, and displayed normal karyotypes. All lines were transgene-free and capable of in vitro differentiation into the three germ layers. These iPSC lines provide tools to investigate p.Thr369Met variant-specific PD mechanisms and contribute to the development and refinement of targeted therapeutics.

Accumulating evidence shows that excess cholesterol and glucose uptake stimulates the expansion of hematopoietic stem/progenitor cells and myeloid progenitors, resulting in increased production of inflammatory cells and atherosclerotic progression. However, the role of other metabolites in plaque progression remains unclear. Hereby, we observed elevated α-ketoglutarate levels in granulocyte-monocyte progenitors (GMPs) of Ldlr-/- mice on a high-fat diet (HFD), determined by targeted metabolomics. On top of HFD, α-ketoglutarate administration further increased GMP proportion, myeloid cell production, and plaque progression in Ldlr-/- mice. The regulation of α-ketoglutarate in atherosclerosis required the expression of its receptor, oxoglutarate receptor 1 (OXGR1), in bone marrow cells (BMCs), as transplantation of OXGR1-/- BMCs attenuated plaque progression compared to transplantation of OXGR1+/+ BMCs in HFD-fed Ldlr-/- recipients. Using targeted metabolomics, single-cell RNA sequencing and validation experiments, we demonstrated that the α-ketoglutarate/OXGR1 axis upregulated the expression of purine nucleoside phosphorylase (PNP) in GMPs, which promoted de novo purine biosynthesis and reduced the levels of nicotinamide mononucleotide and nicotinamide adenine dinucleotide (NAD), thereby disturbing mitochondrial homeostasis and increasing the production of myeloid cells. Furthermore, proteomics data revealed that PNP treatment regulated the redox status by increasing the expression of NAD kinase (NADK), thereby accelerating NAD consumption. Additionally, PNP promoted the transcriptional activation of NF-κB via ubiquitin, enhancing ROS production and inflammation in lineage-/low cells. Spearman's correlation analysis revealed a positive association between isocitrate and low-density lipoprotein cholesterol levels in human plasma. Overall, HFD potentiated α-ketoglutarate, contributing to atherosclerosis.

NOTCH3 variants cause CADASIL (cerebral autosomal dominant arteriopathy and subcortical infarcts and leukoencephalopathy), the most common monogenetic form of small vessel disease (SVD) and vascular dementia (VaD). The molecular mechanisms driving CADASIL pathogenesis remain poorly understood, and no specific treatments are currently available. NOTCH3 is mainly expressed in vascular smooth muscle cells (VSMCs) that arise from different embryonic origins. Using human induced pluripotent stem cell (iPSC) models, we generated origin-specific VSMCs and found that cerebral, but not peripheral, VSMC mimics are selectively vulnerable to NOTCH3 variants. CADASIL iPSC-derived brain-specific VSMCs acquired a synthetic phenotype, accompanied with extensive extracellular matrix accumulation and impaired cell adhesion leading to anoikis. Furthermore, an endothelial-independent nitric oxide signaling was substantially impaired in CADASIL iPSC-derived VSMCs. Phosphodiesterase-5 inhibition successfully reversed the functional abnormality and survival of mutant VSMCs. Our findings uncovered mechanistic insights and suggest a viable therapeutic strategy for NOTCH3-associated SVD/VaD, reinforcing the value of patient-specific iPSCs for disease modeling and potential drug discovery.

It has been demonstrated that both hUCMSC-exo and Cyasterone exhibit protective effects against steroid-induced osteonecrosis of the femoral head (SIONFH). Additionally, studies have shown that CTSD N-glycosylation influences BMSC apoptosis. Based on these findings, we aim to investigate the mechanism of hUCMSCs-exo@Cyasterone in the Dex-induced BMSCs model of SIONFH, focusing on its regulatory role in CTSD N-glycosylation during apoptosis.

Developmental potency-the ability of cells to differentiate into specialized identities-is progressively lost during development. This phenomenon, known as lineage restriction, is poorly understood. Here, we show that a cell's developmental potency is associated with which genes retain transcriptional potency, and that a molecular relay progressively strips the genome of transcriptional potency during differentiation. Mechanistically, genes chromatinized into nucleosomes can intrinsically lack transcriptional potency, remaining silent even when their transcriptional activators are present. Naive pluripotent stem cells uniquely possess the capacity to restore genome-wide transcriptional potency, but such capacity is decommissioned when cells transition into the primed pluripotent state. Thereafter, placeholder factors (PFs) in stem cells counteract chromatinization to preserve transcriptional potency of specific silent genes, thereby maintaining developmental potency for downstream lineages requiring these genes. As differentiation proceeds, PFs disappear. The genes they protect can then permanently lose transcriptional potency via chromatinization, leading to irreversible lineage restriction.

Toxoplasma gondii is a widespread parasite that impacts both human and animal health. Increasing use of organoid model systems has made previously challenging aspects of the T. gondii lifecycle more accessible. The media for these organoid systems are highly complex with many growth factors and pathway inhibitors that promote stem cell retention or differentiation of the cells. We noticed changes in T. gondii growth and development in our intestinal organoid system and wanted to determine if this was driven by cell type or media components. We found that low concentrations of SB202190 (a p38 MAPK inhibitor) and A83-01 (an ALK 4/5/7 receptor inhibitor) are each sufficient to alter T. gondii growth even in fibroblast cells. Further investigation with our qPCR panel of T. gondii stage markers revealed that these compounds promote bradyzoite cyst development and prime parasites for pre-sexual and sexual stage gene expression. As these complex organoid systems become more common in microbiology research, this study highlights the role of organoid media components in controlling pathogen growth and development.

Tendons are specialized connective tissues that transmit mechanical forces from muscle to bone, ensuring joint stability and efficient locomotion. Their homeostasis and regenerative capacity depend on the interplay between extracellular matrix (ECM), resident and recruited cell populations, and immune-mediated signaling. This review provides an overview of tendon structure and composition, emphasizing the collagen-based organization and the functional role of non-collagenous matrix components in mechanotransduction and cell signaling. The heterogeneity of tendon-resident cells, including tenocytes, tendon stem/progenitor cells, and vascular- and immune-associated cells, is discussed, highlighting their roles in tissue maintenance, adaptation, and repair. Tendon aging is characterized by altered cellular responsiveness, ECM disorganization, and reduced capacity to resolve inflammation, predisposing tissues to degeneration and chronic tendinopathies. Emerging evidence underscores the central role of the immune response in both inflammatory and healing processes. Key bioactive compounds used in tendinopathy management, such as collagen, vitamin C, vitamin D, methylsulfonylmethane, hyaluronic acid, and manganese, are discussed regarding their mechanistic effects on collagen synthesis, matrix remodeling, oxidative stress, immune modulation, and cell-matrix interactions. Overall, tendon health emerges from a dynamic balance between structural integrity, cellular activity, and immune regulation, supporting the rationale for targeted nutritional strategies to promote tendon homeostasis and regeneration.