Differentiation Of Hematopoietic Stem Cells Research Articles

The dynamics of hematopoiesis over the human lifespan.

Over a lifetime, hematopoietic stem cells (HSCs) adjust their lineage output to support age-aligned physiology. In model organisms, stereotypic waves of hematopoiesis have been observed corresponding to defined age-biased HSC hallmarks. However, how the properties of hematopoietic stem and progenitor cells change over the human lifespan remains unclear. To address this gap, we profiled individual transcriptome states of human hematopoietic stem and progenitor cells spanning gestation, maturation and aging. Here we define the gene expression networks dictating age-specific differentiation of HSCs and the dynamics of fate decisions and lineage priming throughout life. We additionally identifiy and functionally validate a fetal-specific HSC state with robust engraftment and multilineage capacity. Furthermore, we observe that classification of acute myeloid leukemia against defined transcriptional age states demonstrates that utilization of early life transcriptional programs associates with poor prognosis. Overall, we provide a disease-relevant framework for heterochronic orientation of stem cell ontogeny along the real time axis of the human lifespan.

A system-level model reveals that transcriptional stochasticity is required for hematopoietic stem cell differentiation

HSCs differentiation has been difficult to study experimentally due to the high number of components and interactions involved, as well as the impact of diverse physiological conditions. From a 200-node network, that was grounded on experimental data, we derived a 21-node regulatory network by collapsing linear pathways and retaining the functional feedback loops. This regulatory network core integrates key nodes and interactions underlying HSCs differentiation, including transcription factors, metabolic, and redox signaling pathways. We used Boolean, continuous, and stochastic dynamic models to simulate the hypoxic conditions of the HSCs niche, as well as the patterns and temporal sequences of HSCs transitions and differentiation. Our findings indicate that HSCs differentiation is a plastic process in which cell fates can transdifferentiate among themselves. Additionally, we found that cell heterogeneity is fundamental for HSCs differentiation. Lastly, we found that oxygen activates ROS production, inhibiting quiescence and promoting growth and differentiation pathways of HSCs.

Role of MicroRNAs in Chronic Myeloid Leukemia (CML) Treatment, Biomarkers, and Resistance to Tyrosine Kinase Inhibitor: A Bioinformatics-Based Analysis

Chronic myeloid leukemia (CML) is a myeloproliferative disorder caused by the reciprocal translocation of the BCR-ABL1 oncogene, which activates tyrosine kinase resulting in uncontrolled cell proliferation and apoptosis suppression. Although Imatinib (IM) is an effective treatment, IM resistance remains a significant concern. Therefore, microRNAs (miRNAs) have emerged as potential alternative therapies. These short, non-coding RNAs (20-22 nucleotides) regulate gene expression by binding to the 3' untranslated region (3'UTR) of target genes. The study aims to identify miRNAs linked to CML, determine miRNA’s target genes, construct a protein-protein interaction (PPI) network, and analyze pathways and gene ontology. A literature search using the keywords “microRNA”, and “chronic myeloid leukemia” yielded relevant papers, which were screened and categorized into three groups: 1) miRNA associated with TKI resistance, 2) miRNA as biomarkers or leukemogenesis, and 3) miRNA as therapy. Target genes for the identified miRNAs were determined using DIANA tools and miRTarBase. Gene ontology and pathway analysis were conducted using DAVID, while PPI and network visualization were performed using STRING, Cytoscape, and ClueGO. Thirteen miRNAs were selected, targeting 782 genes and forming 16 clusters. ClueGO identified clusters associated with key biological processes, including G1/S cell cycle transition, miRNA-mediated gene silencing, hematopoietic stem cell differentiation, and apoptosis regulation. Target genes are also significant in the CML pathway and other cancer pathways, such as p53, ErbB, FoxO, autophagy, apoptosis, VEGF, TNF, and microRNA. Notably, hsa-miR-16 emerged as the most promising therapeutic and biomarker candidate for CML, highlighting its role in critical pathways.

NR4A1 and NR4A2 orphan nuclear receptors regulate endothelial-to-hematopoietic transition in mouse hematopoietic stem cell specification.

Hematopoietic stem cells (HSCs) sustain life-long hematopoiesis and emerge during mid-gestation from hemogenic endothelial progenitors via an endothelial-to-hematopoietic transition (EHT). The full scope of molecular mechanisms governing this process remains unclear. The NR4A subfamily of orphan nuclear receptors act as tumor suppressors in myeloid leukemogenesis and have never been implicated in HSC specification. Here, we report that Nr4a1 and Nr4a2 expression is upregulated in hemogenic endothelium during EHT. Progressive genetic ablation of Nr4a gene dosage results in a gradual decrease in numbers of nascent c-Kit+ hematopoietic progenitors in developing embryos, c-Kit+ cell cluster size in the dorsal aorta, and a block in HSC maturation, revealed by an accumulation of pro-HSCs and pre-HSC-type I cells and decreased numbers of pre-HSC-type II cells. Consistent with these observations, cells isolated from embryonic day 11.5 Nr4a1-/-; Nr4a2-/- aorta-gonads-mesonephros are devoid of in vivo long-term hematopoietic repopulating potential. Molecularly, employing spatial transcriptomic analysis we determined that the genetic ablation of Nr4a1 and Nr4a2 prevents Notch signaling from being downregulated in intra-aortic clusters and thus for pro-HSCs to mature into HSCs. Interestingly, this defect is partially rescued by ex vivo culture of dissected aorta-gonads-mesonephros with SCF, IL3 and FLT3L, which may bypass Notch-dependent regulation. Overall, our data reveal a role for the NR4A family of orphan nuclear receptors in EHT.

Abstract 4137935: Adipogenesis in Bone Marrow Niche under Cardiac Stress Worsens Cardiac Function

Background: We have recently reported that repetitive cardiac decompensation with multimorbidity often experienced by patients with heart failure (HF) is attributed to epigenetic modifications of hematopoietic stem cells (HSCs) in the bone marrow (BM). HF reprogrammed HSCs differentiation and altered tissue macrophage homeostasis. These findings demonstrate that the BM can carry an innate immune memory of cardiac stress that may exacerbate HF and predispose other organs to pathology. Aims: Because the stemness of HSCs is mainly regulated by mesenchymal stromal cells (MSCs) in the BM niche, we investigated phenotypic alterations of MSCs under cardiac stress. Methods&Results: Transcriptome analysis of MSCs showed preferential differentiation toward adipocytes in murine pressure overload models. In vitro assays and histological BM sections also support this finding. Furthermore, single-cell RNA sequencing of MSCs demonstrated that the percentage of adipocyte-primed MSCs increased in proportion to the severity of cardiac dysfunction, and also correlated with the frequency of myeloid-lineage progenitor cells. To investigate the influence of adipo-lineage MSCs on HSCs, we conducted BM transplantation supplemented with MSCs from control or HF mice. Recipient mice transplanted with HF-MSCs showed significant increases in myeloid-biased multipotent progenitors in BM and myeloid cells in peripheral blood. Additionally, the number of proinflammatory cardiac macrophages was significantly increased in the HF-MSCs group, promoting cardiac fibrosis and dysfunction. Conclusions: Our results demonstrated that the BM niche could perceive cardiac stress in the form of adipocytic skewing of MSCs in the setting of HF, which changed the differentiation behavior in HSCs and ultimately led to further deterioration of cardiac function through the impaired differentiation of circulating monocytes into cardiac macrophages. Therefore, suppressing the adipocytic differentiation of MSCs could have a novel therapeutic potential to avoid repeated HF events.

Hematopoietic Stem Cell Function and Differentiation Is Regulated By DCAF7 through Polycomb Repressive Complex 1 (PRC1) Modulation

Hematopoietic Stem Cell Function and Differentiation Is Regulated By DCAF7 through Polycomb Repressive Complex 1 (PRC1) Modulation

Age-associated imbalance in immune cell regeneration varies across individuals and arises from a distinct subset of stem cells

The age-associated decline in immunity manifests as imbalanced adaptive and innate immune cells, which originate from the aging of the stem cells that sustain their regeneration. Aging variation across individuals is well recognized, but its mechanism remains unclear. Here, we used high-throughput single-cell technologies to compare mice of the same chronological age that exhibited early or delayed immune aging phenotypes. We found that some hematopoietic stem cells (HSCs) in early aging mice upregulated genes related to aging, myeloid differentiation, and stem cell proliferation. Delayed aging was instead associated with genes involved in stem cell regulation and the response to external signals. These molecular changes align with shifts in HSC function. We found that the lineage biases of 30% to 40% of the HSC clones shifted with age. Moreover, their lineage biases shifted in opposite directions in mice exhibiting an early or delayed aging phenotype. In early aging mice, the HSC lineage bias shifted toward the myeloid lineage, driving the aging phenotype. In delayed aging mice, HSC lineage bias shifted toward the lymphoid lineage, effectively counteracting aging progression. Furthermore, the anti-aging HSC clones did not increase lymphoid production but instead decreased myeloid production. Additionally, we systematically quantified the frequency of various changes in HSC differentiation and their roles in driving the immune aging phenotype. Taken together, our findings suggest that temporal variation in the aging of immune cell regeneration among individuals primarily arises from differences in the myelopoiesis of a distinct subset of HSCs. Therefore, interventions to delay aging may be possible by targeting a subset of stem cells.

Maternal NO2 exposure and fetal growth restriction: Hypoxia transmission and lncRNAs-proinflammation-mediated abnormal hematopoiesis

Epidemiological studies show a strong correlation between air pollution and fetal growth restriction (FGR), but existing results are controversial due to inherent limitations, such as causality of specific pollutants, developmental origin, and maternal-fetal transmission. To address this controversy, we first conducted a retrospective analysis of 28,796 newborns and revealed that maternal nitrogen dioxide (NO2) exposure during the second trimester was positively associated with FGR, with an adjusted odds ratio of 1.075 (95% confidence interval: 1.020-1.133) per 10 μg/m3 NO2 increase for small for gestational age. Then, by establishing an animal model of prenatal NO2 exposure, we confirmed its adverse effects on embryonic growth and hematopoiesis in the yolk sac and fetal liver, primarily affecting the differentiation of hematopoietic stem and progenitor cells and erythroid maturation. By applying internal exposure analyses coupled with 15N isotope tracing, we found that maternal NO2 inhalation induced acquired methemoglobinemia through its byproducts and placental hypoxia in pregnant mice. Importantly, by combining transcriptional profiling, bioinformatics analysis, and RNA binding protein immunoprecipitation (RIP)/chromatin immunoprecipitation (CHIP), we clarified that placental-fetal hypoxia transmission activated hypoxia-inducible factors, disturbed hematopoiesis through the hypoxia-inducible factor 1β-long noncoding RNAs-CCAAT/enhancer binding protein alpha-proinflammatory signaling pathway, ultimately contributing to FGR progression. These findings provide insights for risk prevention and clinical intervention to promote child well-being in NO2-polluted areas.

Maintenance of hematopoietic stem cells by tyrosine-unphosphorylated STAT5 and JAK inhibition

AbstractAdult hematopoietic stem cells (HSCs) are responsible for the lifelong production of blood and immune cells, a process regulated by extracellular cues, including cytokines. Many cytokines signal through the conserved Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway in which tyrosine-phosphorylated STATs (pSTATs) function as transcription factors. STAT5 is a pivotal downstream mediator of several cytokines known to regulate hematopoiesis, but its function in the HSC compartment remains poorly understood. In this study, we show that STAT5-deficient HSCs exhibit an unusual phenotype, including reduced multilineage repopulation and self-renewal, combined with reduced exit from quiescence and increased differentiation. This was driven not only by the loss of canonical pSTAT5 signaling, but also by the loss of distinct transcriptional functions mediated by STAT5 that lack canonical tyrosine phosphorylation (uSTAT5). Consistent with this concept, expression of an unphosphorylatable STAT5 mutant constrained wild-type HSC differentiation, promoted their maintenance, and upregulated transcriptional programs associated with quiescence and stemness. The JAK1/2 inhibitor, ruxolitinib, which increased the uSTAT5:pSTAT5 ratio, had similar effects on murine HSC function; it constrained HSC differentiation and proliferation, promoted HSC maintenance, and upregulated transcriptional programs associated with stemness. Ruxolitinib also enhanced serial replating of normal human hematopoietic stem and progenitor cells (HSPCs), calreticulin-mutant murine HSCs, and HSPCs obtained from patients with myelofibrosis. Our results therefore reveal a previously unrecognized interplay between pSTAT5 and uSTAT5 in the control of HSC function and highlight JAK inhibition as a potential strategy for enhancing HSC function during ex vivo culture. Increased levels of uSTAT5 may also contribute to the failure of JAK inhibitors to eradicate myeloproliferative neoplasms.

The Role of SIRT1 in Leukemia.

Leukemia is a type of hematological malignancy (HM) caused by uncontrolled proliferation, apoptosis, and differentiation of hematopoietic stem cells (HSCs). Leukemia cells proliferate greatly in the bone marrow (BM), infiltrate other tissues and organs, and affect the normal hematopoietic function. Although the emergence of new targeted agents and immune agents has improved the prognosis of patients, due to the complex pathogenic factors and heterogeneity of leukemia, there are still some patients with poor prognosis. Recent studies have shown that silent information regulator 1 (SIRT1) is involved in the proliferation, apoptosis, metabolism, and senescence of leukemia cells. As a double-edged sword in leukemia cells, SIRT1 can both promote and inhibit the growth of leukemia cells. Since its mechanism of action has not been elucidated, it is urgent to explore the regulatory mechanism of SIRT1 in leukemia. In this review, we discussed the mechanisms of SIRT1 in different aspects of leukemia, providing a theoretical basis for the treatment of patients with leukemia.

Relationship between adipocytes and hematological tumors in the bone marrow microenvironment: a literature review.

The bone marrow microenvironment is closely related to normal hematopoiesis and hematologic tumors. Adipocytes are an important part of the bone marrow microenvironment, in which they can release free fatty acids (FFAs) through lipolysis and secrete adipocytokines, etc., and participate in normal hematopoiesis, which is closely related to the occurrence and treatment of hematological tumors. In this review, we aim to discuss how bone marrow adipocytes (BMAs) can influence the proliferation, apoptosis, and chemotherapy resistance of cancer cells by reprogramming lipid metabolism and the secretion of various adipocytokines. Studies from 2000 to July 2024 were reviewed from PubMed, Springer Link, and the Web of Science using the keywords bone marrow microenvironment, adipocytes, lipid metabolism, adipocytokines, hematological tumor, cancer, and their combinations. Unreliable articles such as those that are old and have a low impact factor are excluded, and there is no restriction on language. Adipocytes can regulate the proliferation and differentiation of hematopoietic stem cells (HSCs) by secreting inflammatory factors and adipocytokines to maintain hematopoietic homeostasis. Adipocytes can also stimulate and accelerate the occurrence and progression of hematological tumors by secreting adipocytokines and mediating the reprogramming of lipid metabolism. Moreover, abundant adipocytes in bone marrow can protect tumor cells by physically blocking and/or secreting cytokines, leading to chemotherapy resistance. Therefore, the targeted inhibition of related lipid metabolism pathways and adipocytokines might be a potential therapeutic target for hematological tumors, which would be helpful to inhibit tumor growth and correct chemotherapy resistance.

Vasopressin drives aberrant myeloid differentiation of hematopoietic stem cells, contributing to depression in mice

Psychological stress is often linked to depression and can also impact the immune system, illustrating the interconnectedness of mental health and immune function. Hematopoietic stem cells (HSCs) can directly sense neuroendocrine signals in bone marrow and play a fundamental role in the maintenance of immune homeostasis. However, it is unclear how psychological stress impacts HSCs in depression. Here, we report that neuroendocrine factor arginine vasopressin (AVP) promotes myeloid-biased HSC differentiation by activating neutrophils. AVP administration increases neutrophil and Ly6Chi monocyte production by triggering HSCs that rely on intrinsic S100A9 in mice. When stimulated with AVP, neutrophils return to the bone marrow and release interleukin 36G (IL-36G), which interacts with interleukin 1 receptor-like 2 (IL-1RL2) on HSCs to produce neutrophils with high Elane expression that infiltrate the brain and induce neuroinflammation. Together, these findings define HSCs as a relay between psychological stress and myelopoiesis and identify the IL-36G-IL-1RL2 axis as a potential target for depression therapy.

Next-Generation Sequencing-based Genetic Landscape and its Clinical Implications for Egyptian Patients with Acute Myeloid Leukemia and Myelodysplastic Syndrome

Abstract Background Myeloid malignancies are a heterogeneous group of clonal disorders characterized by disturbed hematopoietic stem cells self-renewal, proliferation, and differentiation capacity as a result of genetic and epigenetic changes. The molecular landscape of these diseases is complex involving many molecular alterations. Several techniques have been used to identify these genetic alterations including; FISH, RT-PCR (real time-PCR) and recently next generation sequencing (NGS) that is capable of detecting copy number variations (CNV) or translocations by a fast less expensive technique making it more practical in clinical practice. Objectives Designing a genetic map for Egyptian population with myeloid and detecting the prognostic impact of these genetic alterations. Patients and Methods Myeloid NGS Oncomine 79-gene panel was applied on 42 patients diagnosed with myeloid neoplasms (Mainly AML & MDS) recruited from the hematology unit, and their follow up till 12 months. Results Among the different studied groups, the highest NGS variants were found in AML compared to other myeloid neoplasms, while the percentage of patients with no NGS variants is higher in MDS (77.8%). The most frequently mutated genes detected in myeloid neoplasms were NPM1 mutation in 8 patients (19%), followed by NRAS mutation in 7 patients (16.7%). BCR-ABL1 and CALR mutations were significantly more common in the MPN group (P- value =0.000). TET2 was significantly more common in MDS/MPN patients (P-value =0.027). TP53 mutation was detected in all myeloid neoplasms (Mainly in MDS) except AML (P-value =0.027). NPM1 was significantly more frequent in AML group (P-value =0.042). There was a significant correlation between the presence of NGS variants and the clinical outcome, as the presence of one or more NGS variants is associated with poor clinical outcome & lower survival rate (p value =0.038). Conclusion Assessment of clinically important genetic alterations by NGS is essential for the diagnosis, prognosis, monitor measurable residual disease and detect predictive mutational markers/therapeutic targets in myeloid neoplasms. However, it cannot identify structural abnormalities, so simultaneous cytogenetic analysis to have a complete picture of the genomic profile is essential.

A bispecific nanosystem activates endogenous natural killer cells in the bone marrow for haematologic malignancies therapy.

Haematologic malignancies commonly arise from the bone marrow lesion, yet there are currently no effective targeted therapies against tumour cells in this location. Here we constructed a bone-marrow-targeting nanosystem, CSF@E-Hn, which is based on haematopoietic-stem-cell-derived nanovesicles adorned with gripper ligands (aPD-L1 and aNKG2D) and encapsulated with colony-stimulating factor (CSF) for the treatment of haematologic malignancies. CSF@E-Hn targets the bone marrow and, thanks to the gripper ligands, pulls together tumour cells and natural killer cells, activating the latter for specific tumour cell targeting and elimination. The therapeutic efficacy was validated in mice bearing acute myeloid leukaemia and multiple myeloma. The comprehensive assessment of the post-treatment bone marrow microenvironment revealed that the integration of CSF into a bone-marrow-targeted nanosystem promoted haematopoietic stem cell differentiation, boosted memory T cell generation and maintained bone homoeostasis, with long-term prevention of relapse. Our nanosystem represents a promising strategy for the treatment of haematologic malignancies.

Epitope prime editing shields hematopoietic cells from CD123 immunotherapy for acute myeloid leukemia

Acute myeloid leukemia (AML) is a malignant cancer characterized by abnormal differentiation of hematopoietic stem and progenitor cells (HSPCs). While chimeric antigen receptor T (CAR-T) cell immunotherapies target AML cells, they often induce severe on-target/off-tumor toxicity by attacking normal cells expressing the same antigen. Here, we used base editors (BEs) and a prime editor (PE) to modify the epitope of CD123 on HSPCs, protecting healthy cells from CAR-T-induced cytotoxicity while maintaining their normal function. Although BE effectively edits epitopes, complex bystander products are a concern. To enhance precision, we optimized prime editing, increasing the editing efficiency from 5.9% to 78.9% in HSPCs. Epitope-modified cells were resistant to CAR-T lysis while retaining normal differentiation and function. Furthermore, BE- or PE-edited HSPCs infused into humanized mice endowed myeloid lineages with selective resistance to CAR-T immunotherapy, demonstrating a proof-of-concept strategy for treating relapsed AML.

27-Hydroxycholesterol Negatively Affects the Function of Bone Marrow Endothelial Cells in the Bone Marrow.

Hematopoietic stem cells (HSCs) reside in specific microenvironments that facilitate their regulation through both internal mechanisms and external cues. Bone marrow endothelial cells (BMECs), which are found in one of these microenvironments, play a vital role in controlling the self-renewal and differentiation of HSCs during hematological stress. We previously showed that 27-hydroxycholesterol (27HC) administration of exogenous 27HC negatively affected the population of HSCs and progenitor cells by increasing the reactive oxygen species levels in the bone marrow. However, the effect of 27HC on BMECs is unclear. To determine the function of 27HC in BMECs, we employed magnetic-activated cell sorting to isolate CD31+ BMECs and CD31- cells. We demonstrated the effect of 27HC on CD31+ BMECs and HSCs. Treatment with exogenous 27HC led to a decrease in the number of BMECs and reduced the expression of adhesion molecules that are crucial for maintaining HSCs. Our results demonstrate that BMECs are sensitively affected by 27HC and are crucial for HSC survival.

Obesity modulates hematopoietic stem cell fate decision via IL-1β induced p38/MAPK signaling pathway

BackgroundObesity is accompanied by inflammation, which significantly affects the homeostasis of the immune microenvironment. Hematopoietic stem cells (HSCs), residing primarily in the bone marrow, play a vital role in maintaining and producing diverse mature blood cell lineages for the adult hematopoietic and immune systems. However, how HSCs development is affected by obese-promoting inflammation, and the mechanism by which HSC hematopoietic potency is affected by inflammatory signals originating from the obese-promoting changes on bone marrow niche remain unclear. This study elucidates the relationship between obesity-promoting inflammation and HSC fate determination.MethodsThe obesity mice model was established by feeding C57BL/6J mice a high-fat diet (HFD) containing 60% kcal fat. After 6 weeks, HSCs were analyzed using flow cytometry and identified key inflammation cytokine. Transcriptome sequencing techniques were used to discern the distinct pathways in HSCs. Ultimately, confirming the biological mechanism of obesity-induced HSC fate changes via Anakinra blocking specific inflammatory signals.ResultsObesity caused by HFD changed the physical and biochemical properties of the bone marrow niche. In the HFD mice, the population of long-term HSCs in the bone marrow was decreased and facilitated HSCs differentiation towards the myeloid lineage. In addition, HFD increased expression of the inflammatory factor IL-1β in the bone marrow, and a significantly increased expression of IL-1r1 and active p38/MAPK signaling pathway were detected in the HSCs. Inhibition of IL-1β further normalized the expression of genes in p38/MAPK pathway and reversed HSC fate.ConclusionsThese findings have been demonstrated that the p38/MAPK signaling pathway in HSCs is activated by elevated levels of IL-1β within the HSC niche in obese models, thereby regulating HSC differentiation. It suggested a direct link between obesity-promoting inflammation and myeloid differentiation bias of HSCs in the HFD mice.Graphical abstract

Developments of Fms-like Tyrosine Kinase 3 Inhibitors as Anticancer Agents for AML Treatment.

FMS-like tyrosine kinase 3 (FLT3) is a commonly mutated gene in acute myeloid leukemia. As a receptor tyrosine kinase (RTK), FLT3 plays a role in the proliferation and differentiation of hematopoietic stem cells. As the most frequent molecular alteration in AML, FLT3 has drawn the attention of many researchers, and a lot of small molecule inhibitors targeting FLT3 have been intensively investigated as potential drugs for AML therapy. In this paper, PubMed and SciFinder® were used as a tool; the publications about "FLT3 inhibitor" and "Acute myeloid leukemia" were surveyed from 2014 to the present with an exclusion of those published as patents. In this study, the structural characterization and biological activities of representative FLT3 inhibitors were summarized. The major challenges and future directions for further research are discussed. Recently, numerous FLT3 inhibitors have been discovered and employed in FLT3-mutated AML treatment. In order to overcome the drug resistance caused by FLT3 mutations, screening multitargets FLT3 inhibitors has become the main research direction. In addition, the emergence of irreversible FLT3 inhibitors also provides new ideas for discovering new FLT3 inhibitors.

Reprogramming hematopoietic stem cell metabolism in lung cancer: glycolysis, oxidative phosphorylation, and the role of 2-DG

Hematopoietic stem cells (HSCs) exhibit significant functional and metabolic alterations within the lung cancer microenvironment, contributing to tumor progression and immune evasion by increasing differentiation into myeloid-derived suppressor cells (MDSCs). Our aim is to analyze the metabolic transition of HSCs from glycolysis to oxidative phosphorylation (OXPHOS) in lung cancer and determine its effects on HSC functionality. Using a murine Lewis Lung Carcinoma lung cancer model, we conducted metabolic profiling of long-term and short-term HSCs, as well as multipotent progenitors, comparing their metabolic states in normal and cancer conditions. We measured glucose uptake using 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)Amino]-2-Deoxyglucose (2-NBDG) and assessed levels of lactate, acetyl-coenzyme A, and ATP. Mitochondrial functionality was evaluated through flow cytometry, alongside the impact of the glucose metabolism inhibitor 2-DG on HSC differentiation and mitochondrial activity. HSCs under lung cancer conditions showed increased glucose uptake and lactate production, with an associated rise in OXPHOS activity, marking a metabolic shift. Treatment with 2-DG led to decreased T-HSCs and MDSCs and an increased red blood cell count, highlighting its potential to influence metabolic and differentiation pathways in HSCs. This study provides novel insights into the metabolic reprogramming of HSCs in lung cancer, emphasizing the critical shift from glycolysis to OXPHOS and its implications for the therapeutic targeting of cancer-related metabolic pathways.

Co-delivery of protopanaxatriol/icariin into niche cells restores bone marrow niches to rejuvenate HSCs for chemotherapy-induced myelosuppression

BackgroundUp to 80 % of chemotherapeutic drugs induce myelosuppression in patients. Chemotherapy not only impairs of hematopoietic stem cells (HSCs) but also damages bone marrow niches (vascular and endosteal). Current treatments for myelosuppression overlook these chemotherapy-induced damages to bone marrow niches and the critical role of niche restoration on hematopoietic regeneration. Ginsenoside protopanaxatriol (PPT) protects vascular endothelium from injury, while icariin (ICA) promotes osteogenic differentiation. The combination of PPT and ICA aims to restore damaged vascular and endosteal niches, thus rejuvenating HSCs for treating myelosuppression. PurposeThis study aims to develop effective, bone marrow niche-directed PPT/ICA therapies for treating chemotherapy-induced myelosuppression. Methods3D cell spheroids were used to investigate the effects of PPT/ICA on cell-cell interactions in vascular niches, osteogenesis, and extracellular matrix (ECM) secretion in endosteal niches. In vitro mimic niche models were designed to access the drug combination's efficacy in rejuvenating and mobilizing in HSCs within bone marrow niches. The delivery capability of PPT/ICA to key niche cell types (mesenchymal stromal cells (MSCs), endothelial cells (ECs), and osteoblasts (OBs)) via nanocarriers has been determined. DSS6 peptide-modified nanoparticles (DSS6-NPs) were prepared for specific co-delivery of PPT/ICA into key niche cell populations in vivo. ResultsPPT can prevent vascular niche injury by restoring vascular EC cell-cell adhesion and the intercellular interactions between ECs and MSCs in 5-fluorouracil (5-FU)-damaged cell spheroids. ICA repaired 5-FU-damaged endosteal niches by promoting osteogenesis and ECM secretion. The combination of PPT and ICA restores key HSC niche factor gene expressions, normalizing HSC differentiation and mobilization. The in vitro cellular uptake efficiency of nanocarriers in a mimic niche is positively correlated with their in vivo delivery into bone marrow niche cells. DSS6-NPs greatly enhance the delivery of PPT/ICA into MSCs and OBs within bone marrow niches. Co-loading of PPT/ICA into DSS6-NPs effectively repairs damaged bone marrow niches and promotes HSC rejuvenation in vivo. ConclusionThe combination of PPT and ICA effectively prevents injury to the vascular and endosteal niches, thereby promoting hematopoietic regeneration in the bone marrow. This study provides novel niche-directed PPT/ICA therapies for managing chemotherapy-induced myelosuppression.