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Hematopoietic stem progenitor cells (HSPCs) undergo phenotypical and functional changes during their emergence and development. Although the molecular programs governing the development of human hematopoietic stem cells (HSCs) have been investigated broadly,the relationships between dynamic metabolic alterations and their functions remain poorly characterized. In this study,we comprehensively described the proteomics of HSPCs in the human fetal liver (FL),umbilical cord blood (UCB),and adult bone marrow (aBM). The metabolic state of human HSPCs was assessed via a Seahorse assay,RT‒PCR,and flow cytometry-based metabolic-related analysis. To investigate whether perturbing glutathione metabolism affects reactive oxygen species (ROS) production,the metabolic state,and the expansion of human HSPCs,HSPCs were treated with buthionine sulfoximine (BSO),an inhibitor of glutathione synthetase,and N-acetyl-L-cysteine (NAC). We investigated the metabolomic landscape of human HSPCs from the fetal,perinatal,and adult developmental stages by in-depth quantitative proteomics and predicted a metabolic switch from the oxidative state to the glycolytic state during human HSPC development. Seahorse assays,mitochondrial activity,ROS level,glucose uptake,and protein synthesis rate analysis supported our findings. In addition,immune-related pathways and antigen presentation were upregulated in UCB or aBM HSPCs,indicating their functional maturation upon development. Glutathione-related metabolic perturbations resulted in distinct responses in human HSPCs and progenitors. Furthermore,the molecular and immunophenotypic differences between human HSPCs at different developmental stages were revealed at the protein level for the first time. The metabolic landscape of human HSPCs at three developmental stages (FL,UCB,and aBM),combined with proteomics and functional validations,substantially extends our understanding of HSC metabolic regulation. These findings provide valuable resources for understanding human HSC function and development during fetal and adult life. The online version contains supplementary material available at 10.1186/s13287-024-03930-x. View Publication

The roles of the transcriptional factor SIX2 have been identified in several tumors. However,its roles in gastric cancer (GC) progression have not yet been revealed. Our objective is to explore the impact and underlying mechanisms of SIX2 on the stemness of GC cells. Lentivirus infection was employed to establish stable expression SIX2 or PFN2 in GC cells. Gain- and loss-of-function experiments were conducted to detect changes of stemness markers,flow cytometry profiles,tumor spheroid formation,and tumor-initiating ability. ChIP,RNA-sequencing,tissue microarray,and bioinformatics analysis were performed to reveal the correlation between SIX2 and PFN2. The mechanisms underlying the SIX2/PFN2 loop-mediated effects were elucidated through tissue microarray analysis,RNA stability assay,IP-MS,Co-Immunoprecipitation,and inhibition of the JNK signaling pathway. The stemness of GC cells was enhanced by SIX2. Mechanistically,SIX2 directly bound to PFN2’s promoter and promoted PFN2 activity. PFN2,in turn,promoted the mRNA stability of SIX2 by recruiting RNA binding protein YBX-1,subsequently activating the downstream MAPK/JNK pathway. This study unveils the roles of SIX2 in governing GC cell stemness,defining a novel SIX2/PFN2 regulatory loop responsible for this regulation. This suggests the potential of targeting the SIX2/PFN2 loop for GC treatment (Graphical Abstracts). The online version contains supplementary material available at 10.1186/s12967-024-05618-5. View Publication

Rhodiola species have been utilized as functional foods in Asia and Europe for promoting health. Research has demonstrated that Rhodiola has the potential to alleviate inflammatory bowel disease (IBD) in animal models. However,the specific active components and the underlying mechanism for ameliorating intestinal damage remain unclear. This study aims to explore the relieving effect of Rosavin (Rov),a known active constituent of Rhodiola,in IBD and the regulatory mechanisms. The therapeutic effect of Rov was evaluated using a murine model of acute colitis induced by dextran sulfate sodium salt (DSS). Inflammatory cytokines and neutrophil activation markers were measured by corresponding kits. Immunohistochemistry,immunofluorescence,TUNEL,and EdU assays were applied to investigate the tight conjunction proteins expression,epithelial marker expression,number of apoptotic cells,and epithelial proliferation,respectively. The protection effect of Rov on gut epithelial injury was assessed using TNF-α-induced intestinal organoids. Additinally,RNA sequencing was applied to observe the genetic alteration profile in these intestinal organoids. Oral administration of Rov significantly attenuated weight loss and restored colon length in mice. Notably,Rov treatment led to decreased levels of pro-inflammatory cytokines and neutrophil activation markers while increasing anti-inflammatory factors. Importantly,Rov restored intestinal despair by increasing the number of Lgr5 + stem cells,Lyz1 + Paneth cells and Muc2 + goblet cells in intestines of colitis mice,displaying reduced epithelial apoptosis and recovered barrier function. In TNF-α-induced intestinal organoids,Rov facilitated epithelial cell differentiation and protected against TNF-α-induced damage. RNA sequencing revealed upregulation in the gene expression associated with epithelial cells (including Lgr5 +,Lyz1 + and Muc2 + cells) proliferation and defensin secretion,unveiling the protective mechanisms of Rov on the intestinal epithelial barrier. Rov holds potential as a natural prophylactic agent against IBD,with its protective action on the intestinal epithelium being crucial for its therapeutic efficacy. View Publication

Intrahepatic cholangiocarcinoma (iCCA) is a lethal primary liver tumor characterized by clinical aggressiveness,poor prognosis,and scarce therapeutic possibilities. Therefore,new treatments are urgently needed to render this disease curable. Since cumulating evidence supports the oncogenic properties of the Heat Shock Factor 1 (HSF1) transcription factor in various cancer types,we investigated its pathogenetic and therapeutic relevance in iCCA. Levels of HSF1 were evaluated in a vast collection of iCCA specimens. The effects of HSF1 inactivation on iCCA development in vivo were investigated using three established oncogene-driven iCCA mouse models. In addition,the impact of HSF1 suppression on tumor cells and tumor stroma was assessed in iCCA cell lines,human iCCA cancer-associated fibroblasts (hCAFs),and patient-derived organoids. Human preinvasive,invasive,and metastatic iCCAs displayed widespread HSF1 upregulation,which was associated with a dismal prognosis of the patients. In addition,hydrodynamic injection of a dominant-negative form of HSF1 (HSF1dn),which suppresses HSF1 activity,significantly delayed cholangiocarcinogenesis in AKT/NICD,AKT/YAP,and AKT/TAZ mice. In iCCA cell lines,iCCA hCAFs,and patient-derived organoids,administration of the HSF1 inhibitor KRIBB-11 significantly reduced proliferation and induced apoptosis. Cell death was profoundly augmented by concomitant administration of the Bcl-xL/Bcl2/Bcl-w inhibitor ABT-263. Furthermore,KRIBB-11 reduced mitochondrial bioenergetics and glycolysis of iCCA cells. The present data underscore the critical pathogenetic,prognostic,and therapeutic role of HSF1 in cholangiocarcinogenesis. The online version contains supplementary material available at 10.1186/s13046-024-03177-7. View Publication

Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease leading to motor neuron loss. Currently mutations in > 40 genes have been linked to ALS,but the contribution of many genes and genetic mutations to the ALS pathogenic process remains poorly understood. Therefore,we first performed comparative interactome analyses of five recently discovered ALS-associated proteins (C21ORF2,KIF5A,NEK1,TBK1,and TUBA4A) which highlighted many novel binding partners,and both unique and shared interactors. The analysis further identified C21ORF2 as a strongly connected protein. The role of C21ORF2 in neurons and in the nervous system,and of ALS-associated C21ORF2 variants is largely unknown. Therefore,we combined human iPSC-derived motor neurons with other models and different molecular cell biological approaches to characterize the potential pathogenic effects of C21ORF2 mutations in ALS. First,our data show C21ORF2 expression in ALS-relevant mouse and human neurons,such as spinal and cortical motor neurons. Further,the prominent ALS-associated variant C21ORF2-V58L caused increased apoptosis in mouse neurons and movement defects in zebrafish embryos. iPSC-derived motor neurons from C21ORF2-V58L-ALS patients,but not isogenic controls,show increased apoptosis,and changes in DNA damage response,mitochondria and neuronal excitability. In addition,C21ORF2-V58L induced post-transcriptional downregulation of NEK1,an ALS-associated protein implicated in apoptosis and DDR. In all,our study defines the pathogenic molecular and cellular effects of ALS-associated C21ORF2 mutations and implicates impaired post-transcriptional regulation of NEK1 downstream of mutant C21ORF72 in ALS. The online version contains supplementary material available at 10.1186/s40478-024-01852-6. View Publication

Recent advances in imaging suggested that spatial organization of hematopoietic cells in their bone marrow microenvironment (niche) regulates cell expansion,governing progression,and leukemic transformation of hematological clonal disorders. However,our ability to interrogate the niche in pre-malignant conditions has been limited,as standard murine models of these diseases rely largely on transplantation of the mutant clones into conditioned mice where the marrow microenvironment is compromised. Here,we leveraged live-animal microscopy and ultralow dose whole body or focal irradiation to capture single cells and early expansion of benign/pre-malignant clones in the functionally preserved microenvironment. 0.5 Gy whole body irradiation (WBI) allowed steady engraftment of cells beyond 30 weeks compared to non-conditioned controls. In-vivo tracking and functional analyses of the microenvironment showed no change in vessel integrity,cell viability,and HSC-supportive functions of the stromal cells,suggesting minimal inflammation after the radiation insult. The approach enabled in vivo imaging of Tet2 + /− and its healthy counterpart,showing preferential localization within a shared microenvironment while forming discrete micro-niches. Notably,stationary association with the niche only occurred in a subset of cells and would not be identified without live imaging. This strategy may be broadly applied to study clonal disorders in a spatial context. View Publication

Astrocytes are essential for the formation and maintenance of neural networks. However,a major technical challenge for investigating astrocyte function and disease-related pathophysiology has been the limited ability to obtain functional human astrocytes. Despite recent advances in human pluripotent stem cell (hPSC) techniques,primary rodent astrocytes remain the gold standard in coculture with human neurons. We demonstrate that a combination of leukemia inhibitory factor (LIF) and bone morphogenetic protein-4 (BMP4) directs hPSC-derived neural precursor cells to a highly pure population of astroglia in 28 d. Using single-cell RNA sequencing,we confirm the astroglial identity of these cells and highlight profound transcriptional adaptations in cocultured hPSC-derived astrocytes and neurons,consistent with their further maturation. In coculture with human neurons,multielectrode array recordings revealed robust network activity of human neurons in a coculture with hPSC-derived or rat astrocytes [3.63 ± 0.44 min −1 (hPSC-derived),2.86 ± 0.64 min −1 (rat); p = 0.19]. In comparison,we found increased spike frequency within network bursts of human neurons cocultured with hPSC-derived astrocytes [56.31 ± 8.56 Hz (hPSC-derived),24.77 ± 4.04 Hz (rat); p < 0.01],and whole-cell patch-clamp recordings revealed an increase of postsynaptic currents [2.76 ± 0.39 Hz (hPSC-derived),1.07 ± 0.14 Hz (rat); p < 0.001],consistent with a corresponding increase in synapse density [14.90 ± 1.27/100 μm 2 (hPSC-derived),8.39 ± 0.63/100 μm 2 (rat); p < 0.001]. Taken together,we show that hPSC-derived astrocytes compare favorably with rat astrocytes in supporting human neural network activity and maturation,providing a fully human platform for investigating astrocyte function and neuronal-glial interactions. View Publication

Streptococcus pneumoniae is a global priority respiratory pathogen that kills over a million people annually. The pore-forming cytotoxin,pneumolysin (PLY) is a major virulence factor. Here,we found that recombinant PLY as well as wild-type pneumococcal strains,but not the isogenic PLY mutant,upregulated the shedding of extracellular vesicles (EVs) harboring membrane-bound toxin from human THP-1 monocytes. PLY-EVs induced cytotoxicity and hemolysis dose-dependently upon internalization by recipient monocyte-derived dendritic cells. Proteomics analysis revealed that PLY-EVs are selectively enriched in key inflammatory host proteins such as IFI16,NLRC4,PTX3,and MMP9. EVs shed from PLY-challenged or infected cells induced dendritic cell maturation and primed them to infection. In vivo,zebrafish administered with PLY-EVs showed pericardial edema and mortality. Adoptive transfer of bronchoalveolar-lavage-derived EVs from infected mice to healthy recipients induced lung damage and inflammation in a PLY-dependent manner. Our findings identify that host EVs released during infection mediate pneumococcal pathogenesis. Subject areas: Microbiology,Bacteriology,Cell biology View Publication

The growth factor Neuregulin-1 (NRG1) has pleiotropic roles in proliferation and differentiation of the stem cell niche in different tissues. It has been implicated in gut,brain and muscle development and repair. Six isoform classes of NRG1 and over 28 protein isoforms have been previously described. Here we report a new class of NRG1,designated NRG1-VII to denote that these NRG1 isoforms arise from a myeloid-specific transcriptional start site (TSS) previously uncharacterized. Long-read sequencing was used to identify eight high-confidence NRG1-VII transcripts. These transcripts presented major structural differences from one another,through the use of cassette exons and alternative stop codons. Expression of NRG1-VII was confirmed in primary human monocytes and tissue resident macrophages and induced pluripotent stem cell-derived macrophages (iPSC-derived macrophages). Isoform switching via cassette exon usage and alternate polyadenylation was apparent during monocyte maturation and macrophage differentiation. NRG1-VII is the major class expressed by the myeloid lineage,including tissue-resident macrophages. Analysis of public gene expression data indicates that monocytes and macrophages are a primary source of NRG1. The size and structure of class VII isoforms suggests that they may be more diffusible through tissues than other NRG1 classes. However,the specific roles of class VII variants in tissue homeostasis and repair have not yet been determined. The online version contains supplementary material available at 10.1186/s12864-024-10723-2. View Publication

Intermediate-length repeat expansions in ATAXIN-2 (ATXN2) are the strongest genetic risk factor for amyotrophic lateral sclerosis (ALS). At the molecular level,ATXN2 intermediate expansions enhance TDP-43 toxicity and pathology. However,whether this triggers ALS pathogenesis at the cellular and functional level remains unknown. Here,we combine patient-derived and mouse models to dissect the effects of ATXN2 intermediate expansions in an ALS background. iPSC-derived motor neurons from ATXN2-ALS patients show altered stress granules,neurite damage and abnormal electrophysiological properties compared to healthy control and other familial ALS mutations. In TDP-43 Tg -ALS mice,ATXN2-Q33 causes reduced motor function,NMJ alterations,neuron degeneration and altered in vitro stress granule dynamics. Furthermore,gene expression changes related to mitochondrial function and inflammatory response are detected and confirmed at the cellular level in mice and human neuron and organoid models. Together,these results define pathogenic defects underlying ATXN2-ALS and provide a framework for future research into ATXN2-dependent pathogenesis and therapy. Subject terms: Amyotrophic lateral sclerosis,Molecular neuroscience,Cellular neuroscience View Publication

Hypomethylating agents (HMAs) are frontline therapies for Myelodysplastic Neoplasms (MDS) and Acute Myeloid Leukemia (AML). However,acquired resistance and treatment failure are commonplace. To address this,we perform a genome-wide CRISPR-Cas9 screen in a human MDS-derived cell line,MDS-L,and identify TOPORS as a loss-of-function target that synergizes with HMAs,reducing leukemic burden and improving survival in xenograft models. We demonstrate that depletion of TOPORS mediates sensitivity to HMAs by predisposing leukemic blasts to an impaired DNA damage response (DDR) accompanied by an accumulation of SUMOylated DNMT1 in HMA-treated TOPORS-depleted cells. The combination of HMAs with targeting of TOPORS does not impair healthy hematopoiesis. While inhibitors of TOPORS are unavailable,we show that inhibition of protein SUMOylation with TAK-981 partially phenocopies HMA-sensitivity and DDR impairment. Overall,our data suggest that the combination of HMAs with inhibition of SUMOylation or TOPORS is a rational treatment option for High-Risk MDS (HR-MDS) or AML. Subject terms: Myelodysplastic syndrome,Acute myeloid leukaemia,Sumoylation View Publication

DNA hypomethylating agents (HMAs) are used for the treatment of myeloid malignancies,although their therapeutic effects have been unsatisfactory. Here we show that CRISPR-Cas9 screening reveals that knockout of topoisomerase 1-binding arginine/serine-rich protein ( TOPORS ),which encodes a ubiquitin/SUMO E3 ligase,augments the efficacy of HMAs on myeloid leukemic cells with little effect on normal hematopoiesis,suggesting that TOPORS is involved in resistance to HMAs. HMAs are incorporated into the DNA and trap DNA methyltransferase-1 (DNMT1) to form DNA-DNMT1 crosslinks,which undergo SUMOylation,followed by proteasomal degradation. Persistent crosslinking is cytotoxic. The TOPORS RING finger domain,which mediates ubiquitination,is responsible for HMA resistance. In TOPORS knockout cells,DNMT1 is stabilized by HMA treatment due to inefficient ubiquitination,resulting in the accumulation of unresolved SUMOylated DNMT1. This indicates that TOPORS ubiquitinates SUMOylated DNMT1,thereby promoting the resolution of DNA-DNMT1 crosslinks. Consistently,the ubiquitination inhibitor,TAK-243,and the SUMOylation inhibitor,TAK-981,show synergistic effects with HMAs through DNMT1 stabilization. Our study provides a novel HMA-based therapeutic strategy that interferes with the resolution of DNA-DNMT1 crosslinks. Subject terms: Myelodysplastic syndrome,Myelodysplastic syndrome View Publication