技术资料

Mitochondrial diseases display pathological phenotypes according to the mixture of mutant versus wild-type mitochondrial DNA (mtDNA),known as heteroplasmy. We herein examined the impact of nuclear reprogramming and clonal isolation of induced pluripotent stem cells (iPSC) on mitochondrial heteroplasmy. Patient-derived dermal fibroblasts with a prototypical mitochondrial deficiency diagnosed as MELAS demonstrated mitochondrial dysfunction with reduced oxidative reserve due to heteroplasmy at position G13513A in the ND5 subunit of complex I. Bioengineered iPSC clones acquired pluripotency with multi-lineage differentiation capacity and demonstrated reduction in mitochondrial density and oxygen consumption distinguishing them from the somatic source. Consistent with the cellular mosaicism of the original patient-derived fibroblasts,the MELAS-iPSC clones contained a similar range of mtDNA heteroplasmy of the disease-causing mutation with identical profiles in the remaining mtDNA. High-heteroplasmy iPSC clones were used to demonstrate that extended stem cell passaging was sufficient to purge mutant mtDNA,resulting in isogenic iPSC subclones with various degrees of disease-causing genotypes. Upon comparative differentiation of iPSC clones,improved cardiogenic yield was associated with iPSC clones containing lower heteroplasmy compared to isogenic clones with high heteroplasmy. Thus,mtDNA heteroplasmic segregation within patient-derived stem cell lines enables direct comparison of genotype/phenotype relationships in progenitor cells and lineage-restricted progeny,and indicates that cell fate decisions are regulated as a function of mtDNA mutation load. The novel nuclear reprogramming-based model system introduces a disease-in-a-dish tool to examine the impact of mutant genotypes for MELAS patients in bioengineered tissues and a cellular probe for molecular features of individual mitochondrial diseases. View Publication

Glioblastoma multiforme is the most common glioma variant in adults and is highly malignant. Tumors are thought to harbor a subpopulation of stem-like cancer cells,with the bulk resembling neural progenitor-like cells that are unable to fully differentiate. Although multiple pathways are known to be involved in glioma tumorigenesis,the role of Wnt signaling has been poorly described. Here,we show that Dishevelled 2 (Dvl2),a key component of the Wnt signaling pathway,is overexpressed in human gliomas. RNA interference-mediated depletion of Dvl2 blocked proliferation and promoted the differentiation of cultured human glioma cell lines and primary,patient-derived glioma cells. In addition,Dvl2 depletion inhibited tumor formation after intracranial injection of glioblastoma cells in immunodeficient mice. Inhibition of canonical Wnt/β-catenin signaling also blocked proliferation,but unlike Dvl2 depletion,did not induce differentiation. Finally,Wnt5a,a noncanonical Wnt ligand,was also required for glioma cell proliferation. The data therefore suggest that both canonical and noncanonical Wnt signaling pathways downstream of Dvl2 cooperate to maintain the proliferative capacity of human glioblastomas. View Publication

The Disrupted in Schizophrenia 1 (DISC1) gene is disrupted by a balanced chromosomal translocation (1; 11) (q42; q14.3) in a Scottish family with a high incidence of major depression,schizophrenia,and bipolar disorder. Subsequent studies provided indications that DISC1 plays a role in brain development. Here,we demonstrate that suppression of DISC1 expression reduces neural progenitor proliferation,leading to premature cell cycle exit and differentiation. Several lines of evidence suggest that DISC1 mediates this function by regulating GSK3beta. First,DISC1 inhibits GSK3beta activity through direct physical interaction,which reduces beta-catenin phosphorylation and stabilizes beta-catenin. Importantly,expression of stabilized beta-catenin overrides the impairment of progenitor proliferation caused by DISC1 loss of function. Furthermore,GSK3 inhibitors normalize progenitor proliferation and behavioral defects caused by DISC1 loss of function. Together,these results implicate DISC1 in GSK3beta/beta-catenin signaling pathways and provide a framework for understanding how alterations in this pathway may contribute to the etiology of psychiatric disorders. View Publication

Fatty-acid-hydroxylase-associated neurodegeneration (FAHN) is a rare neurodegenerative disorder caused by loss-of-function mutations in the FA2H gene,leading to impaired enzymatic activity and resulting in myelin sheath instability,demyelination,and axonal degeneration. In this study,we established a human in vitro model using neurons and oligodendrocytes derived from induced pluripotent stem cells (hiPSCs) of a FAHN patient. This coculture system enabled the investigation of myelination processes and myelin integrity in a disease-relevant context. Analyses using immunofluorescence and Western blot revealed impaired expression and localisation of key myelin proteins in oligodendrocytes and cocultures. FA2H-deficient cells showed reduced myelination,shortened internodes,and disrupted formation of the nodes of Ranvier. Additionally,we identified autophagy defects—a hallmark of many neurodegenerative diseases—including reduced p62 expression,elevated LC3B levels,and impaired fusion of autophagosomes with lysosomes. This study presents a robust hiPSC-based model to study FAHN,offering new insights into the molecular pathology of the disease. Our findings suggest that FA2H mutations compromise both the structural integrity of myelin and the efficiency of the autophagic machinery,highlighting potential targets for future therapeutic interventions. View Publication

CRISPR/Cas9 genome editing has emerged as a promising treatment for genetic diseases like β-thalassemia. Editing γ-globin promoters to disrupt ZBTB7A/LRF or BCL11A binding sites has shown potential for reactivating fetal hemoglobin and treating sickle cell disease. However,its application to β 0 -thalassemia/HbE disease remains unclear. This study utilized CRISPR/Cas9 to disrupt these sites in mobilized CD34 + hematopoietic stem /progenitor cells from healthy donors and β 0 -thalassemia/HbE patients. The editing efficiency for the BCL11A site (75–92%) was higher than for the ZBTB7A/LRF site (57–60%). Both disruptions similarly increased fetal hemoglobin production in healthy donors ( BCL11A 26.2 ± 1.4%,ZBTB7A/LRF 27.9 ± 1.5%) and β 0 -thalassemia/HbE cells ( BCL11A 62.7 ± 0.9%,ZBTB7A/LRF 64.0 ± 1.6%). Off-target effects were absent in BCL11A -edited cells but observed at low frequencies in ZBTB7A/LRF -edited cells. Neither disruption significantly affected erythroid differentiation. These findings highlight the comparable contributions of ZBTB7A/LRF and BCL11A binding sites to γ-globin reactivation. CRISPR/Cas9 editing of either site may offer a potential therapeutic strategy for β 0 -thalassemia/HbE disease. View Publication

Oligomerization is an important regulatory mechanism for many proteins,including oncoproteins and other pathogenic proteins. The oncoprotein Bcr-Abl relies on oligomerization via its coiled coil domain for its kinase activity,suggesting that a designed coiled coil domain with enhanced binding to Bcr-Abl and reduced self-oligomerization would be therapeutically useful. Key mutations in the coiled coil domain of Bcr-Abl were identified that reduce homo-oligomerization through intermolecular charge-charge repulsion yet increase interaction with the Bcr-Abl coiled coil through additional salt bridges,resulting in an enhanced ability to disrupt the oligomeric state of Bcr-Abl. The mutations were modeled computationally to optimize the design. Assays performed in vitro confirmed the validity and functionality of the optimal mutations,which were found to exhibit reduced homo-oligomerization and increased binding to the Bcr-Abl coiled coil domain. Introduction of the mutant coiled coil into K562 cells resulted in decreased phosphorylation of Bcr-Abl,reduced cell proliferation,and increased caspase-3/7 activity and DNA segmentation. Importantly,the mutant coiled coil domain was more efficacious than the wild type in all experiments performed. The improved inhibition of Bcr-Abl through oligomeric disruption resulting from this modified coiled coil domain represents a viable alternative to small molecule inhibitors for therapeutic intervention. View Publication

Heterozygous loss-of-function mutations in GRIN2B,a subunit of the NMDA receptor,cause intellectual disability and language impairment. We developed clonal models of GRIN2B deletion and loss-of-function mutations in a region coding for the glutamate binding domain in human cells and generated neurons from a patient harboring a missense mutation in the same domain. Transcriptome analysis revealed extensive increases in genes associated with cell proliferation and decreases in genes associated with neuron differentiation,a result supported by extensive protein analyses. Using electrophysiology and calcium imaging,we demonstrate that NMDA receptors are present on neural progenitor cells and that human mutations in GRIN2B can impair calcium influx and membrane depolarization even in a presumed undifferentiated cell state,highlighting an important role for non-synaptic NMDA receptors. It may be this function,in part,which underlies the neurological disease observed in patients with GRIN2B mutations. View Publication

Without effective therapy,chronic-phase chronic myeloid leukemia (CP-CML) evolves into an acute leukemia (blast crisis [BC]) that displays either myeloid or B-lymphoid characteristics. This transition is often preceded by a clinically recognized,but biologically poorly characterized,accelerated phase (AP). Here,we report that IKAROS protein is absent or reduced in bone marrow blasts from most CML patients with advanced myeloid disease (AP or BC). This contrasts with primitive CP-CML cells and BCR-ABL1-negative acute myeloid leukemia blasts,which express readily detectable IKAROS. To investigate whether loss of IKAROS contributes to myeloid disease progression in CP-CML,we examined the effects of forced expression of a dominant-negative isoform of IKAROS (IK6) in CP-CML patients' CD34(+) cells. We confirmed that IK6 disrupts IKAROS activity in transduced CP-CML cells and showed that it confers on them features of AP-CML,including a prolonged increased output in vitro and in xenografted mice of primitive cells with an enhanced ability to differentiate into basophils. Expression of IK6 in CD34(+) CP-CML cells also led to activation of signal transducer and activator of transcription 5 and transcriptional repression of its negative regulators. These findings implicate loss of IKAROS as a frequent step and potential diagnostic harbinger of progressive myeloid disease in CML patients. View Publication

SummaryEnergy metabolism in the context of erythropoiesis and related diseases remains largely unexplored. Here,we developed a primary cell model by differentiating hematopoietic stem progenitor cells toward the erythroid lineage and suppressing the mitochondrial oxidative phosphorylation (OXPHOS) pathway. OXPHOS suppression led to differentiation failure of erythroid progenitors and defects in ribosome biogenesis. Ran GTPase-activating protein 1 (RanGAP1) was identified as a target of mitochondrial OXPHOS for ribosomal defects during erythropoiesis. Overexpression of RanGAP1 largely alleviated erythroid defects resulting from OXPHOS suppression. Coenzyme Q10,an activator of OXPHOS,largely rescued erythroid defects and increased RanGAP1 expression. Patients with Diamond-Blackfan anemia (DBA) exhibited OXPHOS suppression and a concomitant suppression of ribosome biogenesis. RNA-seq analysis implied that the substantial mutation (approximately 10%) in OXPHOS genes accounts for OXPHOS suppression in these patients. Conclusively,OXPHOS disruption and the associated disruptive mitochondrial energy metabolism are linked to the pathogenesis of DBA. Graphical abstract Highlights•Disruptive energy metabolism associates with the pathology of DBA•Suppression of OXPHOS leads to differentiation failure of erythroid progenitors•Energy metabolism disruption decreases overall ribosome levels in erythropoiesis•RanGAP1 is a target of OXPHOS pathway for ribosome biogenesis during erythropoiesis Cellular physiology; Cell biology; Developmental biology View Publication

The tumor microenvironment and healing wounds both contain extremely high concentrations of adenosine triphosphate (ATP) compared to normal tissue. The P2Y2 receptor,an ATP-activated purinergic receptor,is typically associated with pulmonary,endothelial,and neurological cell signaling. Here,we examine ATP-dependent signaling in breast epithelial cells and how it is altered in metastatic breast cancer. Using rapid imaging techniques,we show how ATP-activated P2Y2 signaling causes an increase in intracellular Ca 2+ in non-tumorigenic breast epithelial cells,approximately 3-fold higher than their tumorigenic and metastatic counterparts. The non-tumorigenic cells respond to increased Ca 2+ with actin polymerization and localization to the cell edges after phalloidin staining,while the metastatic cells remain unaffected. The increase in intracellular Ca 2+ after ATP stimulation was blunted to control levels using a P2Y2 antagonist,which also prevented actin mobilization and significantly increased cell dissemination from spheroids in non-tumorigenic cells. Furthermore,the lack of Ca 2+ changes and actin mobilization in metastatic breast cancer cells could be due to the reduced P2Y2 expression,which correlates with poorer overall survival in breast cancer patients. This study elucidates the rapid changes that occur after elevated intracellular Ca 2+ in breast epithelial cells and how metastatic cancer cells have adapted to evade this cellular response. View Publication

A large body of evidence suggests that B-cell lymphomas with enhanced Myc expression are associated with an aggressive phenotype and poor prognosis,which makes Myc a compelling therapeutic target. Phosphodiesterase 4B (PDE4B),a main hydrolyzer of cyclic AMP (cAMP) in B cells,was shown to be involved in cell survival and drug resistance in diffuse large B cell lymphomas (DLBCL). However,the interrelationship between Myc and PDE4B remains unclear. Here,we first demonstrate the presence of the Myc-PDE4B feed-forward loop,in which Myc and PDE4B mutually reinforce the expression of each other. Next,the combined targeting of Myc and PDE4 synergistically prevented the proliferation and survival of B lymphoma cells in vitro and in a mouse xenograft model. We finally recapitulated this combinatorial effect in Emu-myc transgenic mice; co-inhibition of Myc and PDE4 suppressed lymphomagenesis and restored B cell development to the wild type level that was associated with marked reduction in Myc levels,unveiling the critical role of the Myc-PDE4B amplification loop in the regulation of Myc expression and the pathogenesis of B cell lymphoma. These findings suggest that the disruption of the Myc-PDE4B circuitry can be exploited in the treatment of B cell malignancies. View Publication

Pancreatic cancer is one of the most malignant cancers,and limited therapeutic options are available. The induction of ferroptosis is considered to be a novel,promising strategy that has potential in cancer treatment,and ferroptosis inducers may be new options for eradicating malignant cancers that are resistant to traditional drugs. The exact mechanism underlying the function of sorcin in the initiation and progression of pancreatic cancer remains unclear. The expression of sorcin in cancer tissues was assessed by analyzing TCGA,GEO and immunohistochemical staining data,and the function of sorcin in the induction of ferroptosis in pancreatic cancer cells was investigated. The mechanism underlying the function of sorcin was revealed through proteomics,co-IP,Ch-IP,and luciferase assays. Natural product screening was subsequently performed to screen for products that interact with sorcin to identify new ferroptosis inducers. We first showed that sorcin expression was positively correlated with the survival and tumor stages of patients with pancreatic cancer,and we revealed that sorcin inhibited ferroptosis through its noncalcium binding function. Furthermore,we discovered that sorcin interacted with PAX5 in the cytoplasm and inhibited PAX5 nuclear translocation,which in turn decreased FBXL12 protein expression and then reduced ALDH1A1 ubiquitination,thus inhibiting ferroptosis. Moreover,an in-house natural product screen revealed that celastrol inhibited the interaction of sorcin and PAX5 by directly binding to the Cys194 residue of the sorcin protein; disruption of the sorcin-PAX5 interaction promoted the nuclear translocation of PAX5,induced the expression of FBXL12,increased the ubiquitylation of ALDH1A1,and eventually induced ferroptosis in pancreatic cancer cells. In this study,we revealed the mechanism of action of sorcin,which is a druggable target for inducing ferroptosis,we identified celastrol as a novel agent that induces ferroptosis,and we showed that disrupting the sorcin-PAX5 interaction is a promising therapeutic strategy for treating pancreatic cancer. The online version contains supplementary material available at 10.1186/s13045-025-01680-8. View Publication