Co-mutations of asxl1 and IDH2 are associated with aggressive acute myeloid leukemia (AML), yet the underlying mechanisms have remained poorly understood. We generated a zebrafish model combining asxl1 mutation and IDH2R172K mutation that recapitulates the clinicopathologic and molecular features of high-risk AML with differentiation blockade and reduced animal survival. The double mutant exhibited promoter hypermethylation, downregulation of tet2 expression, and showed global changes in methylation profiles. Genes pertaining to MAPK and AP-1 pathway were upregulated, associated with NADPH oxidase (NOX) expression and an increase in reactive oxygen species (ROS). Single-cell RNA-sequencing confirmed differentiation arrest in HSC-progenitor with activation of MAPK and AP-1 signaling. The double mutants showed resistance to the IDH2 inhibitor but were sensitive to ROS or DNA methylation targeting. In silico analysis of gene expression of human AML carrying co-mutation of ASXL1/IDH2 also showed activation of the MAPK and AP-1 pathway. Our findings underscored an epigenetic-metabolic signaling circuit driving leukemogenesis and revealed novel therapeutic strategies for this AML subtype.

Novel functions of eosinophils are continually being discovered, yet the regulatory mechanisms underlying eosinophil development-particularly how ubiquitous nutrient metabolites integrate with cell-intrinsic transcriptional programs-remain poorly defined. Using zebrafish and mouse models, we demonstrate that ID2 promotes eosinophil maturation by orchestrating retinoic acid (RA) signaling. We show that ID2 interacts with and inhibits TCF3, thereby relieving TCF3-mediated suppression of Rarg expression and ensuring adequate RA signaling to support eosinophil maturation. Our findings reveal the critical role of the ID2-TCF3-RARγ axis in eosinophil development, illustrating a coordinated regulatory mechanism involving RA signaling and ID2 during eosinophilopoiesis. This study elucidates how nutrient-derived signals are finely tuned during eosinophil lineage development, providing insights for RA-related treatments and dietary interventions in homeostasis and eosinophil-associated diseases.

Using the recent work of Brendle–Wang on the Riemannian positive mass theorem, we prove the spacetime positive mass theorem for asymptotically flat and asymptotically hyperboloidal initial data sets in arbitrary dimension n.

Artificial light at night (ALAN) is an escalating environmental stressor linked to cardiovascular disease, yet its underlying mechanisms remain poorly understood. Here, we investigate the molecular basis of this pathology using zebrafish embryos for mechanistic discovery and murine models for translational validation under a chronic dim-light-at-night (dLAN) paradigm. dLAN exposure induced cardiac injury characterized by pericardial edema and hemodynamic impairment. Transcriptomic profiling revealed dysregulation of inflammatory and oxidative stress pathways, accompanied by marked suppression of the calcium-activated chloride channel accessory protein zclca1. Genetic knockdown ofzclca1 recapitulated core dLAN pathologies, while pharmacological intervention with the chloride-modulating diuretic bumetanide reversed cardiac dysfunction in both species. These findings identify a conserved "dLAN-CLCA-chloride-cardiac injury" axis, wherein light pollution disrupts chloride homeostasis to drive cardiac pathology, suggesting that chloride modulation may represent a potential therapeutic strategy for mitigating light pollution-induced cardiovascular injury.

Myeloid cells play key roles in innate and adaptive immunity. Studying their development and function helps reveal new roles and pathogenic mechanisms of related diseases. Zebrafish, a classical model organism, offers various advantages for studying myeloid cell biology. In this review, we focus on recent advances in myeloid cell development and function using the zebrafish model. The pattern and regulation of myelopoiesis and related disorders, including congenital myeloid cell insufficiency and myeloid malignancies, have been revealed, along with related drugs. Regarding function, we highlight myeloid cells, especially macrophages, in homeostasis and regeneration. The bidirectional interactions between myeloid cells and pathogens in zebrafish also provide valuable insights into the mechanisms of infectious diseases. In summary, we highlight the unique contributions of the zebrafish model, demonstrate its complementary roles in basic research and clinical applications relative to mammalian systems, and look forward to more exciting discoveries using this model in the future.

Background Thrombocytopenia is a serious hematological disorder characterized by low platelet counts, with platelet recovery rate as a key prognostic factor. Current models have limitations such as acute toxicity, non-specific cell ablation, and poor capacity for dynamic observation of recovery. Objectives This study aimed to establish a thrombocyte-specific ablation zebrafish model to study thrombocyte regeneration and screen for pro-recovery compounds. Methods We generated Tg(cd41:eGFP-NTR) zebrafish for inducible thrombocyte ablation using ronidazole (RNZ). The model was characterized via imaging, phenotypic assays, and transcriptomics. A targeted library of 132 compounds was screened, and hits were validated in Chemotherapy-Induced Thrombocytopenia (CIT) and Congenital Amegakaryocytic Thrombocytopenia (CAMT) zebrafish model and human Meg-01 cells. Results RNZ treatment caused rapid and specific depletion of thrombocytes through cell-autonomous apoptosis and macrophage-mediated clearance. This loss led to bleeding symptoms and reduced thrombus formation, resembling key features of thrombocytopenia. Transcriptomic analysis and functional studies showed that Fibroblast Growth Factor (FGF) signaling plays a critical role in thrombocyte recovery. Screening of the compound library identified three novel candidates that significantly accelerated recovery. Notably, tasisulam effectively rescued both CIT and CAMT phenotypes by driving thrombocyte recovery via the ERK signaling pathway. In addition, both tasisulam and 4-methylcatechol promoted thrombopoiesis in human Meg-01 cells, indicating conservation across species. Conclusion This zebrafish model provides exceptional spatiotemporal resolution for investigating the pathogenesis and in vivo recovery dynamics of thrombocytopenia. It serves as a versatile platform for identifying therapeutic agents with cross-species efficacy and for uncovering key mechanisms regulating thrombocyte regeneration, revealing FGF signaling as a central regulator of thrombocyte recovery.

The inflammatory response is a core protective physiological process against stimuli like infection or injury, and can be initiated by autoimmune disorders. It is primarily characterized by neutrophil-dominated leukocytosis and may lead to multiple organ dysfunction in severe cases. Environmental factors play an important role in the inflammatory response. Rare earth elements are not essential elements for living organisms. However, owing to large-scale mining and use, their concentrations in the environment have increased. Thus, rare earth elements are now considered emerging environmental pollutants, and the risks that rare earth elements pose to human health need further investigation. In this study, zebrafish were used as experimental animals, and zebrafish embryos were exposed to the different concentrations of lanthanum chloride (0, 5, 15, and 25 mg/L) to analyze its effect on embryo development and immune system. The number and distribution of zebrafish neutrophils as well as changes in oxidative stress and the expression of genes related to inflammation were analyzed. The results indicated that lanthanum chloride exposure reduced the heart rate, shortened the body length, and increased the yolk area of zebrafish embryos. In addition, exposure to lanthanum chloride caused the diffusion of neutrophils, leading to inflammation in zebrafish. Concurrently, the exposure led to the accumulation of reactive oxygen species in zebrafish, which subsequently resulted in the upregulation of malondialdehyde, catalase, and superoxide dismutase levels. Further experiments revealed that exposure to lanthanum chloride led to the upregulation of several inflammation-related genes, such as il-6, il-8, il-10, and cxcl-c1c, as well as certain TLR4/NF-κB signaling-related genes, including tlr4, myd88, nf-κb p65, il-1β, and tnf-α. The TLR4/NF-κB signaling pathway inhibitor andrographolide can alleviate the inflammatory response induced by lanthanum chloride exposure. In conclusion, lanthanum chloride induced inflammation in zebrafish by activating the TLR4/NF-κB signaling pathway. The study results can provide a reference for evaluating the health risks of rare earth elements in humans.

The widespread use of veterinary antibiotics in animal husbandry, such as tilmicosin (TIL), poses potential threats to environment pollution and human health. In this study, we conducted acute TIL exposure experiment using zebrafish model to explore the toxicological effects. In the concentration range of 20-80 mg/L, TIL did not affect zebrafish body length development but induced idiopathic scoliosis (IS)-like symptoms accompanied by impaired mobility. IS predominantly occurs in adolescents, while the etiology remains unclear. Further studies showed that the combination of quercetin and luteolin effectively alleviated TIL-induced spinal curvature and motor suppression. To explore the underlying mechanism, we performed network pharmacology analysis and enriched the PI3K-Akt pathway. We validated that the expression of key target genes in the PI3K-Akt pathway were significantly activated after TIL exposure, while quercetin and luteolin treatment effectively inhibited the PI3K-Akt pathway activation. Further experiments revealed that TIL exposure decreased brain neural cell apoptosis, thereby causing an increase in neurocytes, interfering with motor ability, and promoting IS-like vertebral malformations, which were especially noticeable during movement. This study expands our understanding that TIL exposure may be a predisposing factor for IS occurrence and progression, while the combination of quercetin and luteolin combination could protect against IS-like symptom by regulating PI3K-Akt pathway.

T lymphocytes, which are essential for cell-mediated immunity in vertebrates, rely on thymic seeding of lymphoid progenitors for commitment, differentiation and maturation. However, the epigenetic programming of lymphoid-primed progenitor migration and differentiation is incompletely understood. Here, we show that zebrafish embryos lacking the epigenetic modulator Atf7ip or Setdb1 methyltransferase exhibit decreased thymic homing and differentiation of lymphoid progenitor cells. We show that Atf7ip regulates T cell progenitor homing and differentiation via Setdb1-triggered H3K9 trimethylation. Atf7ip interacts with Setdb1 to catalyze H3K9me3 modification of the key immune regulator bach2b to derepress the expression of ccr9a and irf4a, thereby promoting lymphoid progenitor homing and intrathymic differentiation. In the absence of Atf7ip or Setdb1, replenishing irf4a or diminishing bach2b restores the thymic trafficking and differentiation of lymphoid progenitor cells. Notably, depletion of ATF7IP by two complementary cre-recombinase alleles in mice (CAG-CreERT2 and Mx1-iCre) impedes the migration of hematopoietic progenitors to the thymus, resulting in declined T lymphopoiesis. These findings establish the role of ATF7IP/SETDB1-mediated epigenetic programming in governing T lymphoid progenitor trafficking and differentiation, with implications for understanding the pathogenesis of human T lymphoid diseases.

Hereditary multiple exostoses (HME) is an autosomal dominant skeletal disorder primarily linked with mutations in Exostosin-1 (EXT1) and Exostosin-2 (EXT2) genes. However, not all HME cases can be explained by these mutations, and its pathogenic mechanisms are not fully understood. Herein, utilizing whole-exome sequencing and genetic screening with a family trio design, we identify two novel rare mutations co-segregating with HME in a Chinese family, including a nonsense mutation (c.204G>A, p.Trp68*) in EXT1 and a missense mutation (c.893T>G, p.Phe298Cys) in FUT7. Functional assays reveal that the FUT7 mutation affects the cellular localization of FUT7 protein and regulates cell proliferation. Notably, the simultaneous loss of fut7 and ext1 in a zebrafish model results in severe chondrodysplasia, indicating a functional link between FUT7 and EXT1 in chondrocyte regulation. Additionally, we unveil that FUT7 p.Phe298Cys reduces EXT1 expression through IL6/STAT3/SLUG axis at the transcription level and through ubiquitination-related proteasomal degradation at the protein level. Together, our findings not only identify novel germline mutations in FUT7 and EXT1 genes, but also highlight the critical interaction between these genes, suggesting a potential 'second-hit' mechanism over EXT1 mutations in HME pathogenesis. This insight enhances our understanding of the mechanisms underlying HME and opens new avenues for potential therapeutic interventions.

Inflammatory bowel disease(IBD)comprises a heterogeneous group of chronic inflammatory conditions of the intestine.Current therapeutic strategies primarily focus on maintaining remission and mitigating the secondary effects rather than reversing its pathogenic mechanisms(Jeong et al.,2019).The pathogenesis of IBD involves intestinal barrier dysfunction,tissue damage,and dysregulated innate and adaptive immune responses(de Souza et al.,2017).

Approximately 30% of patients with myelodysplastic syndrome (MDS) progress to secondary acute myeloid leukemia (sAML) via accumulating gene mutations. Genomic analyses reveal a complex interplay among mutant genes, with co-occurring and mutually exclusive patterns. Hyperactivation of c-MYB and deficiency of PU.1 have been linked to myeloid disorders. We report a case of AML with concurrent PU.1 and c-MYB mutations, exhibiting early onset, high blast count, chemo-resistance, indicating high-risk features, along with elevated Pelger-Huët anomaly (PHA). However, the synergistic mechanism of c-MYB and PU.1 in sAML remains unclear. Using c-Myb-hyperactivation and Pu.1-deficient double-strain (c-mybhyper;pu.1G242D/G242D) zebrafish, we investigated MDS/sAML progression. Surprisingly, the double mutant exhibited a distinct type of neutrophil resembling clinical PHA cells and demonstrated a higher rate of MDS/sAML transformation. Further expression analysis revealed reduced lmnb1 expression in double-mutant zebrafish. Knockdown of lmnb1 resulted in PHA and increased blast cells, while overexpression of lmnb1 in c-mybhyper;pu.1G242D/G242D reduced PHA cell level. This suggests that c-Myb hyperactivation and Pu.1 deficiency synergistically reduce lmnb1 expression, inducing the development of PHA-like neutrophils and promoting MDS/sAML progression in zebrafish. Moreover, coadministration of cell cycle inhibitor cytarabine (Ara-C) and the differential inducer all-trans retinoic acid (ATRA) could effectively relieve the neutrophil expansion and PHA symptoms in c-mybhyper;pu.1G242D/G242D zebrafish. Our findings revealed that c-Myb hyperactivation and Pu.1 deficiency played a synergistic role in sAML development and suggests a phenotypic association between the emergence of PH-like cells and the transformation to sAML. Furthermore, c-mybhyper;pu.1G242D/G242D zebrafish might serve as a suitable sAML model for drug screening.

BACKGROUND: Hematopoietic stem cells (HSCs) maintain blood production via tightly regulated differentiation. Disruptions at this level can lead to myelodysplastic syndromes (MDS), characterized by ineffective hematopoiesis and marrow failure. Despite its clinical use, the antihypertensive and hair-growth agent minoxidil has been linked to hematologic side effects, yet its mechanism remains unknown. METHODS: Compounds affecting hematopoiesis were identified by a small-molecule screen using Tg(mpl:eGFP) zebrafish embryos and validated by immunofluorescent antibody staining. The impact of minoxidil on different blood cell types was determined by whole-mount in situ hybridization. HSPCs proliferation and apoptosis were assessed in Tg(cd41:eGFP) embryos using bromodeoxyuridine (BrdU) incorporation and TUNEL assays. Gene expression changes were profiled by RNA sequencing. Functional relevance of wnt4 was assessed through overexpression and F0 knockout experiments. At suitable concentrations that avoided notable developmental delay, minoxidil demonstrated its dual effects—therapeutic efficacy and hematopoietic toxicity—across larval and adult MDS-like zebrafish and in wild-type mice, and further exerted antiproliferative effects in human malignant hematopoietic cells in vitro. RESULTS: Minoxidil significantly reduced hematopoietic stem and progenitor cell numbers in zebrafish embryos, leading to broad suppression of multiple blood lineages. Transcriptomic profiling revealed that minoxidil downregulated wnt4 expression. Functional validation demonstrated that wnt4 directly modulates HSPC abundance: knockout of wnt4 recapitulated the hematopoietic suppression seen with minoxidil, while overexpression restored HSPC levels. In c-mybhyper MDS-like zebrafish, minoxidil treatment alleviated myeloid hyperplasia at appropriate doses without impairing lymphoid or erythroid lineages. Consistently, minoxidil showed inhibitory effects on human malignant hematopoietic cells in vitro, supporting its conserved suppressive effect on myeloid and progenitor expansion. In both adult zebrafish and wild-type mice, low or intermittent minoxidil dosing preserved hematopoietic integrity, whereas continuous high-dose treatment resulted in multilineage cytopenia. CONCLUSION: Our findings demonstrate that minoxidil modulates hematopoiesis through wnt4 downregulation, resulting in both HSPC suppression and therapeutic alleviation of MDS-like phenotypes. At optimized dosing, minoxidil exhibits hematologic safety in vivo. This study identifies wnt4 as a regulatory node linking pharmacologic intervention to HSPC homeostasis and highlights its therapeutic potential in MDS.

Background: Pepper (Capsicum annuum L.) is a widely cultivated vegetable crop worldwide, with its rich fruit colors providing unique visual traits and economic value. This study investigated the genetic basis of the immature green fruit color by constructing a F2 segregating population derived from a cross between yellow fruit C20 and green fruit C62 parent lines. Methods: Bulked segregant analysis sequencing (BSA-seq) was performed to identify genomic regions associated with fruit color. Candidate genes were pinpointed through functional annotation and genetic variation analysis, supported by SNP markers, genotype analysis, and transcriptome profiling. Results: Two genomic regions associated with fruit color were identified on chromosomes 1 (14.55-20.85 Mb) and 10 (10.15-22.85 Mb), corresponding to previously reported loci pc1 and pc10.1. Two chlorophyll synthesis-related genes, CaAPRR2 and CaGLK2, were identified as candidate regulators of fruit color. Mutations in these genes include a premature stop codon in both CaGLK2 and CaAPRR2. The mutation of CaAPRR2 and CaGLK2 jointly regulate the yellow fruit trait in pepper, with CaGLK2 being the major gene and CaAPRR2 being the minor gene. Transcriptome analysis showed that the expression levels of the two genes increased during the green ripening stage of the parent fruits, with higher expression levels of CaGLK2. Conclusions: This study identifies CaGLK2 and CaAPRR2 as key regulators of immature green fruit color in pepper, with CaGLK2 playing a predominant role. These findings provide a theoretical foundation and data support for elucidating the molecular regulatory mechanisms of fruit color and advancing marker-assisted breeding in pepper.

Polyploidization plays a crucial role in plant evolution and is becoming increasingly important in breeding. Structural variations and epigenomic repatterning have been observed in synthetic polyploidizations. However, the mechanisms underlying the occurrence and their effects on gene expression and phenotype remain unknown. Here, we investigated genome-wide large deletion/duplication regions (DelDups) and genomic methylation dynamics in leaf organs of progeny from the first eight generations of synthetic tetraploids derived from Chinese cabbage (Brassica rapa L. ssp. pekinensis) and cabbage (Brassica oleracea L. var. capitata). One- or two-copy DelDups, with a mean size of 5.70 Mb (400 kb to 65.85 Mb), occurred from the first generation of selfing and thereafter. The duplication of a fragment in one subgenome consistently coincided with the deletion of its syntenic fragment in the other subgenome, and vice versa, indicating that these DelDups were generated by homoeologous exchanges (HEs). Interestingly, the larger the genomic syntenic region, the higher the frequency of DelDups, further suggesting that the pairing of large homoeologous fragments is crucial for HEs. Moreover, we found that the active transcription of continuously distributed genes in local regions is positively associated with the occurrence of HE breakpoints. In addition, the expression of genes within DelDups exhibited a dosage effect, and plants with extra parental genomic fragments generally displayed phenotypes biased toward the corresponding parent. Genome-wide methylation fluctuated remarkably, which did not clearly affect gene expression on a large scale. Our findings provide insights into the early evolution of polyploid genomes, offering valuable knowledge for polyploidization-based breeding. A comprehensive multi-omics landscape across synthetic Brassica napus tetraploids reveals active transcription of homoeologous exchange-related genes.

Cancer is a major global health issue;in 2020,there were 19.29 million new cancer cases and 9.96 million cancer deaths worldwide(Siegel et al.,2023).Despite ongoing research,chemotherapy re-mains the primary treatment due to its broad anti-cancer effects(Marra and Curigliano,2021).However,intravenous chemothera-peutic drugs commonly induce hematotoxicity,necessitating dose adjustments or treatment delays.

Eosinophils are a group of granulocytes well known for their capacity to protect the host from parasites and regulate immune function. Diverse biological roles for eosinophils have been increasingly identified, but the developmental pattern and regulation of the eosinophil lineage remain largely unknown. Herein, we utilize the zebrafish model to analyze eosinophilic cell differentiation, distribution, and regulation. By identifying eslec as an eosinophil lineage-specific marker, we establish a Tg(eslec:eGFP) reporter line, which specifically labeled cells of the eosinophil lineage from early life through adulthood. Spatial-temporal analysis of eslec + cells demonstrates their organ distribution from larval stage to adulthood. By single-cell RNA-Seq analysis, we decipher the eosinophil lineage cells from lineage-committed progenitors to mature eosinophils. Through further genetic analysis, we demonstrate the role of Cebp1 in balancing neutrophil and eosinophil lineages, and a Cebp1-Cebpβ transcriptional axis that regulates the commitment and differentiation of the eosinophil lineage. Cross-species functional comparisons reveals that zebrafish Cebp1 is the functional orthologue of human C/EBPε P27 in suppressing eosinophilopoiesis. Our study characterizes eosinophil development in multiple dimensions including spatial-temporal patterns, expression profiles, and genetic regulators, providing for a better understanding of eosinophilopoiesis.