技术资料

Heme oxygenase-1 (HO-1,HMOX1 ) degrades heme protecting cells from heme-induced oxidative damage. Beyond its well-established cellular functions,heme has emerged as a stabilizer of G-quadruplexes. These secondary DNA structures interfere with DNA replication. We recently revealed that nuclear HO-1 colocalizes with DNA G-quadruplexes and promotes their removal. Here,we investigate whether HO-1 safeguards cells against replication stress. Experiments were conducted in control and HMOX1 -deficient HEK293T cell lines. Immunostaining unveiled that DNA G-quadruplexes accumulated in the absence of HO-1,the effect that was further enhanced in response to δ-aminolevulinic acid (ALA),a substrate in heme synthesis. This was associated with replication stress,as evidenced by an elevated proportion of stalled forks analyzed by fiber assay. We observed the same effects in hematopoietic stem cells isolated from Hmox1 knockout mice and in a lymphoblastoid cell line from an HMOX1 -deficient patient. Interestingly,in the absence of HO-1,the speed of fork progression was higher,and the response to DNA conformational hindrance less stringent,indicating dysfunction of the PARP1-p53-p21 axis. PARP1 activity was not decreased in the absence of HO-1. Instead,we observed that HO-1 deficiency impairs the nuclear import and accumulation of p53,an effect dependent on the removal of excess heme. We also demonstrated that administering ALA is a more specific method for increasing intracellular free heme compared to treatment with hemin,which in turn induces strong lipid peroxidation. Our results indicate that protection against replication stress is a universal feature of HO-1,presumably contributing to its widely recognized cytoprotective activity. View Publication

Breast cancer is the most common cancer in women diagnosed in the U.S. and worldwide. Obesity increases breast cancer risk without clear underlying molecular mechanisms. Our studies demonstrate that circulating adipose fatty acid binding protein (A-FABP,or FABP4) links obesity-induced dysregulated lipid metabolism and breast cancer risk,thus potentially offering a new target for breast cancer treatment. We immunized FABP4 knockout mice with recombinant human FABP4 and screened hybridoma clones with specific binding to FABP4. The potential effects of antibodies on breast cancer cells in vitro were evaluated using migration,invasion,and limiting dilution assays. Tumor progression in vivo was evaluated in various types of tumorigenesis models including C57BL/6 mice,Balb/c mice,and SCID mice. The phenotype and function of immune cells in tumor microenvironment were characterized with multi-color flow cytometry. Tumor stemness was detected by ALDH assays. To characterize antigen-antibody binding capacity,we determined the dissociation constant of selected anti-FABP4 antibodies via surface plasmon resonance. Further analyses in tumor tissue were performed using 10X Genomics Visium spatial single cell technology. Herein,we report the generation of humanized monoclonal antibodies blocking FABP4 activity for breast cancer treatment in mouse models. One clone,named 12G2,which significantly reduced circulating levels of FABP4 and inhibited mammary tumor growth,was selected for further characterization. After confirming the therapeutic efficacy of the chimeric 12G2 monoclonal antibody consisting of mouse variable regions and human IgG1 constant regions,16 humanized 12G2 monoclonal antibody variants were generated by grafting its complementary determining regions to selected human germline sequences. Humanized V9 monoclonal antibody showed consistent results in inhibiting mammary tumor growth and metastasis by affecting tumor cell mitochondrial metabolism. Our current evidence suggests that targeting FABP4 with humanized monoclonal antibodies may represent a novel strategy for the treatment of breast cancer and possibly other obesity- associated diseases. The online version contains supplementary material available at 10.1186/s13058-024-01873-y. View Publication

Olanzapine (OLZ) reverses chronic stress-induced anxiety. Chronic stress promotes cancer development via abnormal neuro-endocrine activation. However,how intervention of brain-body interaction reverses chronic stress-induced tumorigenesis remains elusive. Kras LSL−G12D/WT lung cancer model and LLC1 syngeneic tumor model were used to study the effect of OLZ on cancer stemness and anxiety-like behaviors. Cancer stemness was evaluated by qPCR,western-blotting,immunohistology staining and flow-cytometry analysis of stemness markers,and cancer stem-like function was assessed by serial dilution tumorigenesis in mice and extreme limiting dilution analysis in primary tumor cells. Anxiety-like behaviors in mice were detected by elevated plus maze and open field test. Depression-like behaviors in mice were detected by tail suspension test. Anxiety and depression states in human were assessed by Hospital Anxiety and Depression Scale (HADS). Chemo-sensitivity of lung cancer was assessed by in vivo syngeneic tumor model and in vitro CCK-8 assay in lung cancer cell lines. In this study,we found that OLZ reversed chronic stress-enhanced lung tumorigenesis in both Kras LSL−G12D/WT lung cancer model and LLC1 syngeneic tumor model. OLZ relieved anxiety and depression-like behaviors by suppressing neuro-activity in the mPFC and reducing norepinephrine (NE) releasing under chronic stress. NE activated ADRB2-cAMP-PKA-CREB pathway to promote CLOCK transcription,leading to cancer stem-like traits. As such,CLOCK-deficiency or OLZ reverses NE/chronic stress-induced gemcitabine (GEM) resistance in lung cancer. Of note,tumoral CLOCK expression is positively associated with stress status,serum NE level and poor prognosis in lung cancer patients. We identify a new mechanism by which OLZ ameliorates chronic stress-enhanced tumorigenesis and chemoresistance. OLZ suppresses mPFC-NE-CLOCK axis to reverse chronic stress-induced anxiety-like behaviors and lung cancer stemness. Decreased NE-releasing prevents activation of ADRB2-cAMP-PKA-CREB pathway to inhibit CLOCK transcription,thus reversing lung cancer stem-like traits and chemoresistance under chronic stress. The online version contains supplementary material available at 10.1186/s12964-024-01747-y. View Publication

Hematopoietic aging is associated with decreased hematopoietic stem cell (HSC) self-renewal capacity and myeloid skewing. We report that culture of bone marrow (BM) HSCs from aged mice with epidermal growth factor (EGF) suppressed myeloid skewing,increased multipotent colony formation,and increased HSC repopulation in primary and secondary transplantation assays. Mice transplanted with aged,EGF-treated HSCs displayed increased donor cell engraftment within BM HSCs and systemic administration of EGF to aged mice increased HSC self-renewal capacity in primary and secondary transplantation assays. Expression of a dominant negative EGFR in Scl/Tal1 + hematopoietic cells caused increased myeloid skewing and depletion of long term-HSCs in 15-month-old mice. EGF treatment decreased DNA damage in aged HSCs and shifted the transcriptome of aged HSCs from genes regulating cell death to genes involved in HSC self-renewal and DNA repair but had no effect on HSC senescence. These data suggest that EGFR signaling regulates the repopulating capacity of aged HSCs. Subject areas: Human physiology,cellular physiology,molecular medicine,stem cells research,functional aspects of cell biology View Publication

Chemotherapy-induced peripheral neuropathy (CIPN) is a disabling side effect of cancer chemotherapy that can often limit treatment options for cancer patients or have life-long neurodegenerative consequences that reduce the patient’s quality of life. CIPN is caused by the detrimental actions of various chemotherapeutic agents on peripheral axons. Currently,there are no approved preventative measures or treatment options for CIPN,highlighting the need for the discovery of novel therapeutics and improving our understanding of disease mechanisms. In this study,we utilized human-induced pluripotent stem cell (hiPSC)-derived motor neurons as a platform to mimic axonal damage after treatment with vincristine,a chemotherapeutic used for the treatment of breast cancers,osteosarcomas,and leukemia. We screened a total of 1902 small molecules for neuroprotective properties in rescuing vincristine-induced axon growth deficits. From our primary screen,we identified 38 hit compounds that were subjected to secondary dose response screens. Six compounds showed favorable pharmacological profiles – AZD7762,A-674563,Blebbistatin,Glesatinib,KW-2449,and Pelitinib,all novel neuroprotectants against vincristine toxicity to neurons. In addition,four of these six compounds also showed efficacy against vincristine-induced growth arrest in human iPSC-derived sensory neurons. In this study,we utilized high-throughput screening of a large library of compounds in a therapeutically relevant assay. We identified several novel compounds that are efficacious in protecting different neuronal subtypes from the toxicity induced by a common chemotherapeutic agent,vincristine which could have therapeutic potential in the clinic. The online version contains supplementary material available at 10.1007/s00018-024-05340-x. View Publication

Previous studies have shown that aggregated alpha-synuclein (α-s) protein,a key pathological marker of Parkinson’s disease (PD),can propagate between cells,thus participating in disease progression. This prion-like propagation has been widely studied using in vivo and in vitro models,including rodent and human cell cultures. In this study,our focus was on temporal assessment of functional changes during α-s aggregation and propagation in human induced pluripotent stem cell (hiPSC)-derived neuronal cultures and in engineered networks. Here,we report an engineered circular tripartite human neuronal network model in a microfluidic chip integrated with microelectrode arrays (MEAs) as a platform to study functional markers during α-s aggregation and propagation. We observed progressive aggregation of α-s in conventional neuronal cultures and in the exposed (proximal) compartments of circular tripartite networks following exposure to preformed α-s fibrils (PFF). Furthermore,aggregated forms propagated to distal compartments of the circular tripartite networks through axonal transport. We observed impacts of α-s aggregation on both the structure and function of neuronal cells,such as in presynaptic proteins,mitochondrial motility,calcium oscillations and neuronal activity. The model enabled an assessment of the early,middle,and late phases of α-s aggregation and its propagation during a 13-day follow-up period. While our temporal analysis suggested a complex interplay of structural and functional changes during the in vitro propagation of α-s aggregates,further investigation is required to elucidate the underlying mechanisms. Taken together,this study demonstrates the technical potential of our introduced model for conducting in-depth analyses for revealing such mechanisms. Subject terms: Parkinson's disease,Neurological models View Publication

PU.1 ( SPI1 ) is pivotal in hematopoiesis,yet its role in human endothelial-to-hematopoietic transition (EHT) remains unclear. Comparing human in vivo and in vitro EHT transcriptomes revealed SPI1 ’s regulatory role. Knocking down SPI1 during in vitro EHT led to a decrease in the generation of hematopoietic progenitor cells (HPCs) and their differentiation potential. Through multi-omic analysis,we identified KLF1 and LYL1 - transcription factors specific to erythroid/myeloid and lymphoid cells,respectively - as downstream targets of SPI1 . Overexpressing KLF1 or LYL1 partially rescues the SPI1 knockdown-induced reduction in HPC formation. Specifically,KLF1 overexpression restores myeloid lineage potential,while LYL1 overexpression re-establishes lymphoid lineage potential. We also observed a SPI1 - LYL1 axis in the regulatory network in in vivo EHT. Taken together,our findings shed new light on the role of SPI1 in regulating lineage commitment during EHT,potentially contributing to the heterogeneity of hematopoietic stem cells (HSCs). Subject areas: Biological sciences,Molecular biology,Molecular interaction,Cell biology; View Publication

Riboflavin transporter deficiency type 2 (RTD2) is a rare neurodegenerative autosomal recessive disease caused by mutations in the SLC52A2 gene encoding the riboflavin transporters,RFVT2. Riboflavin (Rf) is the precursor of FAD (flavin adenine dinucleotide) and FMN (flavin mononucleotide),which are involved in different redox reactions,including the energetic metabolism processes occurring in mitochondria. To date,human induced pluripotent stem cells (iPSCs) have given the opportunity to characterize RTD2 motoneurons,which reflect the most affected cell type. Previous works have demonstrated mitochondrial and peroxisomal altered energy metabolism as well as cytoskeletal derangement in RTD2 iPSCs and iPSC-derived motoneurons. So far,no attention has been dedicated to astrocytes. Here,we demonstrate that in vitro differentiation of astrocytes,which guarantee trophic and metabolic support to neurons,from RTD2 iPSCs is not compromised. These cells do not exhibit evident morphological differences nor significant changes in the survival rate when compared to astrocytes derived from iPSCs of healthy individuals. These findings indicate that differently from what had previously been documented for neurons,RTD2 does not compromise the morpho-functional features of astrocytes. View Publication

Proper control of the lineage bias of megakaryocytic and erythroid progenitor cells (MEPs) is of significant importance,the disorder of which will lead to abnormalities in the number and function of platelets and erythrocytes. Unfortunately,the signaling pathways regulating MEP differentiation largely remain to be elucidated. This study aimed to analyze the role and the underlying molecular mechanism of miR-1915-3p in megakaryocytic and erythroid differentiation. We utilized miRNA mimics and miRNA sponge to alter the expression of miR-1915-3p in megakaryocytic and/or erythroid potential cells; siRNA and overexpression plasmid to change the expression of SOCS4,a potential target of miR-1915-3p. The expression of relevant surface markers was detected by flow cytometry. We scanned for miR-1915-3p target genes by mRNA expression profiling and bioinformatic analysis,and confirmed the targeting by dual-luciferase reporter assay,western blot and gain- and lost-of-function studies. One-way ANOVA and t-test were used to analyze the statistical significance. In this study,overexpression or knockdown of miR-1915-3p inhibited or promoted erythroid differentiation,respectively. Accordingly,we scanned for miR-1915-3p target genes and confirmed that SOCS4 is one of the direct targets of miR-1915-3p. An attentive examination of the endogenous expression of SOCS4 during megakaryocytic and erythroid differentiation suggested the involvement of SOCS4 in erythroid/megakaryocytic lineage determination. SOCS4 knockdown lessened erythroid surface markers expression,as well as improved megakaryocytic differentiation,similar to the effects of miR-1915-3p overexpression. While SOCS4 overexpression resulted in reversed effects. SOCS4 overexpression in miR-1915-3p upregulated cells rescued the effect of miR-1915-3p. miR-1915-3p acts as a negative regulator of erythropoiesis,and positively in thrombopoiesis. SOCS4 is one of the key mediators of miR-1915-3p during the differentiation of MEPs. The online version contains supplementary material available at 10.1186/s12959-024-00615-6. View Publication

More than 100 genes have been associated with significantly increased risks of autism spectrum disorders (ASD) with an estimate of ∼1000 genes that may contribute. The new challenge is to investigate the molecular and cellular functions of these genes during neural and brain development,and then even more challenging,to link the altered molecular and cellular phenotypes to the ASD clinical manifestations. In this study,we used single-cell RNA-seq analysis to study one of the top risk genes,CHD8,in cerebral organoids,which models early neural development. We identified 21 cell clusters in the organoid samples,representing non-neuronal cells,neural progenitors,and early differentiating neurons at the start of neural cell fate commitment. Comparisons of the cells with one copy of a CHD8 knockout allele,generated by CRISPR/Cas9 editing,and their isogenic controls uncovered thousands of differentially expressed genes,which were enriched with functions related to neural and brain development,cilium organization,and extracellular matrix organization. The affected genes were also enriched with genes and pathways previously implicated in ASD,but surprisingly not for schizophrenia and intellectual disability risk genes. The comparisons also uncovered cell composition changes,indicating potentially altered neural differential trajectories upon CHD8 reduction. Moreover,we found that cell-cell communications were affected in the CHD8 knockout organoids,including the interactions between neural and glial cells. Taken together,our results provide new data and information for understanding CHD8 functions in the early stages of neural lineage development and interaction. View Publication