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The challenge of expanding haematopoietic stem/progenitor cells (HSPCs) in vitro has limited their clinical application. Human hair follicle mesenchymal stem cells (hHFMSCs) can be reprogrammed to generate intermediate stem cells by transducing OCT4 (hHFMSCs OCT4 ) and pre-inducing with FLT3LG/SCF,and differentiated into erythrocytes. These intermediate cells exhibit gene expression patterns similar to pre-HSCs,making them promising for artificial haematopoiesis. However,further investigation is required to elucidate the in vitro proliferation ability and mechanism underlying the self-renewal of pre-HSCs derived from hHFMSCs. hHFMSCs OCT4 were pre-treated with FLT3LG and SCF cytokines,followed by characterization and isolation of the floating cell subsets for erythroid differentiation through stimulation with hematopoietic cytokines and nutritional factors. Cell adhesion was assessed through disassociation and adhesion assays. OCT4 expression levels were measured using immunofluorescence staining,RT-qPCR,and Western blotting. RNA sequencing and Gene Ontology (GO) enrichment analysis were then conducted to identify proliferation-related biological processes. Proliferative capacity was evaluated through CCK-8,colony formation assays,Ki67 index,and cell cycle analysis. Cytoskeleton was observed through Wright‒Giemsa,Coomassie brilliant blue,and phalloidin staining. Expression of adherens junction (AJ) core members was confirmed through RT‒qPCR,Western blotting,and immunofluorescence staining before and after ZO-1 knockdown. A regulatory network was constructed to determine relationships among cytoskeleton,proliferation,and the AJ pathway. Student’s t tests (GraphPad Prism 8.0.2) were used for group comparisons. The results were considered significant at P < 0.05. Pre-treatment of hHFMSCs OCT4 with FLT3LG and SCF leads to the emergence of floating cell subsets exhibiting small,globoid morphology,suspended above adherent cells,forming colonies,and displaying minimal expression of CD45. Excessive OCT4 expression weakens adhesion in floating hHFMSCs OCT4 . Floating cells moderately enhanced proliferation and undergo cytoskeleton remodelling,with increased contraction and aggregation of F-actin near the nucleus. The upregulation of ZO-1 could impact the expressions of F-actin,E-cadherin,and β-catenin genes,as well as the nuclear positioning of β-catenin,leading to variations in the cytoskeleton and cell cycle. Finally,a regulatory network revealed that the AJ pathway cored with ZO-1 critically bridges cytoskeletal remodelling and haematopoiesis-related proliferation in a β-catenin-dependent manner. ZO-1 improved the self-renewal of pre-HSCs from OCT4-overexpressing hHFMSCs by remodeling the cytoskeleton via the ZO-1-regulated AJ pathway,suggesting floating hHFMSCs OCT4 as the promising seed cells for artificial hematopoiesis. The online version contains supplementary material available at 10.1186/s13287-024-04080-w. View Publication

Inflammation in cystic fibrosis (CF) airways is difficult to treat with well-established regimens often including azithromycin (AZ) as an immunomodulatory drug. As AZ has been reported to require CF transmembrane conductance regulator (CFTR) to be able to reduce interleukin (IL)-8 and given the emergence of highly effective CFTR “triple” modulator therapy (elexacaftor/tezacaftor/ivacaftor; ETI),the aim of this study was to investigate the effect of AZ and ETI,singly and in combination,on ion channel activity and to assess the potential anti-inflammatory effects. Electrophysiological assessment of ETI and AZ was performed on three-dimensional cultures of primary CF human bronchial epithelial (HBE) cells using a Multi Trans-Epithelial Current Clamp. IL-8 from NuLi-1 (non-CF) and CuFi-1 (CF) cells treated with AZ was measured by ELISA. Inflammatory mediators from primary CF HBE cells exposed to tumour necrosis factor-α in the presence of AZ,ETI and their combination,were screened using the Proteome Profiler™ Human Cytokine Array Kit,with selected targets validated by ELISA. AZ did not alter CFTR chloride efflux,nor did it have any synergistic/antagonistic effect in combination with ETI. AZ reduced IL-8 in NuLi-1 but not CuFi-1 cells. The Proteome Profiler™ screen identified several disease-relevant cytokines that were modulated by treatment. Subsequent analysis by ELISA showed IL-8,IL-6,CXCL1 and granulocyte–macrophage colony-stimulating factor to be significantly reduced by treatment with ETI,but not by AZ. Incorporating ETI into the standard of CF care provides an opportunity to re-evaluate therapeutic regimens to reduce treatment burden and safely discontinue chronic treatments such as AZ,without loss of clinical benefit. Identification of redundant treatments in the era of CFTR modulation may improve medication adherence and overcome potential adverse effects associated with the chronic use AZ and other drugs. View Publication

The Sleeping Beauty (SB) transposon system is a useful tool for genetic applications,including gene therapy. We discovered a hyperactive variant of the SB100X transposase,called SB200X. This mutant,resulting from a specific amino acid replacement (Q124C),showed an ∼2-fold increase in transposition activity in various human and murine cells. Other amino acid replacements in position 124 also led to a hyperactive phenotype. Position 124 is located at the very edge of the linker region that connects the DNA-binding and catalytic domains of the transposase. Consistent with a role of the linker in an autoregulatory mechanism called overproduction inhibition (OPI) in the monophyletic group of mariner transposases,we show that the hyperactivity of Q124C manifests at high concentrations of the transposase,suggesting a partial resistance of SB200X to OPI. We demonstrate that the hyperactive phenotype of Q124C can be combined with features of other useful mutations in the SB transposase. Namely,Q124C improves the transposition efficiency of the previously described K248R variant,while maintaining or even slightly improving its safer genome-wide integration profile. The SB200X transposase could enhance the utility of SB transposon-mediated genome engineering in preclinical and clinical applications. View Publication

It is advantageous to culture the ex vivo retina and other tissues at the air-liquid interface to allow for more efficient gas exchange. However,gene delivery to these cultures can be challenging. Electroporation is a fast and robust method of gene delivery,but typically requires submergence in liquid buffer for electrical current flow. We have developed a submergence-free electroporation technique that incorporates an agarose hydrogel disk between the positive electrode and retina. Inner retinal neurons and Müller glia are transfected with increased propensity toward Müller glia transfection after extended time in culture. We also observed an increase in BrdU incorporation in Müller glia following electrical stimulation,and variation in detection of transfected cells from expression vectors with different promoters. This method advances our ability to use ex vivo retinal tissue for genetic studies and should be adaptable for other tissues cultured at an air-liquid interface. Subject areas: Genetic engineering,Methodology in biological sciences,Bioelectrical engineering View Publication

Apigenin (API),a traditionally sourced flavonoid,is recognized for its anti-neoplastic properties. Despite well-documented effects on tumorigenesis,the detailed therapeutic impact on breast cancer stem cells (BCSCs) and the associated molecular mechanisms are yet to be clarified. The objective of this study is to elucidate the therapeutic effects of API on BCSCs and to uncover its molecular mechanisms through network pharmacology and experimental validation. Interactions of API with candidate targets were examined through target screening,enrichment analysis,construction of protein-protein interaction networks,and molecular docking. MCF-7-derived BCSCs were utilized as a model system to investigate and substantiate the anti-BCSC effects of API and the underlying mechanism. Molecular docking studies have shown that API and TP53 exhibit favorable binding affinity. Compared with the negative control group,API effectively suppressed the expression of BCSC-related proteins such as ALDH1A1,NANOG,EpCAM,and MYC,downregulated p-PI3K and p-AKT,and upregulated p53. This study demonstrates that API can play an anti-BCSC role by regulating the PI3K/AKT/p53 pathway in BCSCs of MCF-7 cells,highlighting its potential as a therapeutic agent for targeting BCSCs. View Publication

The introduction of antibody–drug conjugates represents a significant advancement in targeted therapy of acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Our study aims to investigate the role of the DNA damage response pathway and the impact of PARP1 inhibition,utilizing talazoparib,on the response of AML and ALL cells to Gemtuzumab ozogamicin (GO) and Inotuzumab ozogamicin (INO),respectively. AML and ALL cells were treated with GO,INO and γ-calicheamicin in order to induce severe DNA damage and activate the G2/M cell-cycle checkpoint in a dose- and time-dependent manner. The efficacy of PARP1 inhibitors and,in particular,talazoparib in enhancing INO or GO against ALL or AML cells was assessed through measurements of cell viability,cell death,cell cycle progression,DNA damage repair,accumulation of mitotic DNA damage and inhibition of clonogenic capacity. We observed that both ALL and AML cell lines activate the G2/M cell-cycle checkpoint in response to γ-calicheamicin-induced DNA damage,highlighting a shared cellular response mechanism. Talazoparib significantly enhanced the efficacy of INO against ALL cell lines,resulting in reduced cell viability,increased cell death,G2/M cell-cycle checkpoint override,accumulation of mitotic DNA damage and inhibition of clonogenic capacity. Strong synergism was observed in primary ALL cells treated with the combination. In contrast,AML cells exhibited a heterogeneous response to talazoparib in combination with GO. Our findings suggest a potential link between the differential responses of ALL and AML cells to the drug combinations and the ability of talazoparibto override G2/M cell-cycle arrest induced by antibody–drug conjugates. PARP1 emerges as a key player in the response of ALL cells to INO and represents a promising target for therapeutic intervention in this leukemia setting. Our study sheds light on the intricate interplay between the DNA damage response pathway,PARP1 inhibition,and response of γ-calicheamicin-induced DNA damages in AML and ALL. These findings underscore the importance of targeted therapeutic strategies and pave the way for future research aimed at optimizing leukemia treatment approaches. The online version contains supplementary material available at 10.1186/s12967-024-05838-9. View Publication

Transplantation of engineered hematopoietic stem/progenitor cells (HSPCs) showed curative potential in patients affected by neurometabolic diseases treated in early stage. Favoring the engraftment and maturation of the engineered HSPCs in the central nervous system (CNS) could allow enhancing further the therapeutic potential of this approach. Here we unveil that HSPCs haplo-insufficient at the Cx3cr1 (Cx3cr1 −/+ ) locus are favored in central nervous system (CNS) engraftment and generation of microglia-like progeny cells (MLCs) as compared to wild type (Cx3cr1 +/+ ) HSPCs upon transplantation in mice. Based on this evidence,we have developed a CRISPR-based targeted gene addition strategy at the human CX3CR1 locus resulting in an enhanced ability of the edited human HSPCs to generate mature MLCs upon transplantation in immunodeficient mice,and in lineage specific,regulated and robust transgene expression. This approach,which benefits from the modulation of pathways involved in microglia maturation and migration in haplo-insufficient cells,may broaden the application of HSPC gene therapy to a larger spectrum of neurometabolic and neurodegenerative diseases. Subject terms: Targeted gene repair,Haematopoietic stem cells,Microglial cells View Publication

The effect of mechanical cues on cellular behaviour has been reported in multiple studies so far,and a specific aspect of interest is the role of mechanotransductive proteins in neuronal development. Among these,yes-associated protein (YAP) is responsible for multiple functions in neuronal development such as neuronal progenitor cells migration and differentiation while myocardin-related transcription factor A (MRTFA) facilitates neurite outgrowth and axonal pathfinding. Both proteins have indirectly intertwined fates via their signalling pathways. There is little literature investigating the roles of YAP and MRTFA in vitro concerning neurite outgrowth in mechanically confined microenvironments. Moreover,our understanding of their relationship in immature neurons cultured within engineered confined microenvironments is still lacking. In this study,we fabricated,via two-photon polymerization (2PP),2.5D microgrooves and 3D polymeric microchannels,with a diameter range from 5 to 30 μm. We cultured SH-SY5Y cells and differentiated them into immature neuron-like cells on both 2.5D and 3D microstructures to investigate the effect of mechanical confinement on cell morphology and protein expression. In 2.5D microgrooves,both YAP and MRTFA nuclear/cytoplasmic (N/C) ratios exhibited maxima in the 10 μm grooves indicating a strong relation with mechanical-stress-inducing confinement. In 3D microchannels,both proteins’ N/C ratio exhibited minima in presence of 5 or 10 μm channels,a behaviour that was opposite to the ones observed in the 2.5D microgrooves and that indicates how the geometry and mechanical confinement of 3D microenvironments are unique compared to 2.5D ones due to focal adhesion,actin,and nuclear polarization. Further,especially in presence of 2.5D microgrooves,cells featured an inversely proportional relationship between YAP N/C ratio and the average neurite length. Finally,we also cultured human induced pluripotent stem cells (hiPSCs) and differentiated them into cortical neurons on the microstructures for up to 2 weeks. Interestingly,YAP and MRTFA N/C ratios also showed a maximum around the 10 μm 2.5D microgrooves,indicating the physiological relevance of our study. Our results elucidate the possible differences induced by 2.5D and 3D confining microenvironments in neuronal development and paves the way for understanding the intricate interplay between mechanotransductive proteins and their effect on neural cell fate within engineered cell microenvironments. View Publication

Liver cancer stem cells (LCSCs) are thought to drive the metastasis and recurrence,however,the heterogeneity of molecular markers of LCSCs has hindered the development of effective methods to isolate them. This study introduced an effective approach to isolate and culture LCSCs from human primary liver cancer (HPLC),leveraging mouse embryonic fibroblasts (MEFs) as feeder cells in conjunction with using defined medium. Isolated LCSCs were further characterized by multiple approaches. Transcriptome sequencing data analysis was conducted to identify highly expressed genes in LCSCs and classify different subtypes of liver cancers. Total sixteen cell strains were directly isolated from 24 tissues of three types of HPLC without sorting,seven of which could be maintained long-term culture as colony growth on MEFs,which is unique characteristics of stem cells. Even 10 of cloned cells formed the tumors in immunodeficient mice,indicating that those cloned cells were tumorgenic. The histologies and gene expression pattern of human xenografts were very similar to those of HPLC where these cloned cells were isolated. Moreover,putative markers of LCSCs were further verified to all express in cloned cells,confirming that these cells were LCSCs. These cloned LCSCs could be cryopreserved,and still maintained the feature of colony growth on MEFs after the recovery. Compared to suspension culture as conventional approach to culture LCSCs,our approach much better maintained stemness of LCSCs for a long time. To date,these cloned cells could be cultured on MEFs over 12 passages. Moreover,bioinformatics analysis of sequencing data revealed the gene expression profiles in LCSCs,and liver cancers were classified into two subtypes C1 and C2 based on genes associated with the prognosis of LCSCs. Patients of the C2 subtype,which is closely related to the extracellular matrix,were found to be sensitive to treatments such as Cisplatin,Axitinib,JAK1 inhibitors,WNT-c59,Sorafenib,and RO-3306. In summary,this effective approach offers new insights into the molecular landscape of human liver cancers,and the identification of the C2 subtype and its unique response to the treatment pave the way for the creation of more effective,personalized therapeutic strategies. The online version contains supplementary material available at 10.1186/s12967-024-05870-9. View Publication

Pericytes play a crucial role in controlling inflammation and vascular functions in the central nervous system,which are disrupted in Parkinson’s disease (PD). Still,there is a lack of studies on the impact of pericytes on neurodegenerative diseases,and their involvement in the pathology of PD is unclear. Our objective was to investigate the molecular and functional differences between healthy pericytes and pericytes with the LRRK2 G2019S mutation,which is one of the most common mutations associated with PD. Our study employed pericyte-like cells obtained from induced pluripotent stem cells produced from PD patients with the LRRK2 G2019S mutation as well as from healthy individuals. We examined the gene expression profiles of the cells and analyzed how the alterations reflect on their functionality. We have shown differences in the expression of genes related to inflammation and angiogenesis. Furthermore,we observe modified migration speed in PD pericyte-like cells as well as enhanced secretion of inflammatory mediators,such as soluble VCAM-1 and MCP-1,in these pericyte-like cells following exposure to proinflammatory stimuli. In summary,our findings support the notion that pericytes play a role in the inflammatory and vascular changes observed in PD. Further investigation of pericytes could provide valuable insight into understanding the pathogenesis of PD. The online version contains supplementary material available at 10.1186/s12987-024-00592-y. View Publication

Ex vivo activation is a prerequisite to reaching adequate levels of gene editing by homology-directed repair (HDR) for hematopoietic stem and progenitor cell (HSPC)-based clinical applications. Here,we show that shortening culture time mitigates the p53-mediated DNA damage response to CRISPR-Cas9-induced DNA double-strand breaks,enhancing the reconstitution capacity of edited HSPCs. However,this results in lower HDR efficiency,rendering ex vivo culture necessary yet detrimental. Mechanistically,ex vivo activation triggers a multi-step process initiated by p38 mitogen-activated protein kinase (MAPK) phosphorylation,which generates mitogenic reactive oxygen species (ROS),promoting fast cell-cycle progression and subsequent proliferation-induced DNA damage. Thus,p38 inhibition before gene editing delays G1/S transition and expands transcriptionally defined HSCs,ultimately endowing edited cells with superior multi-lineage differentiation,persistence throughout serial transplantation,enhanced polyclonal repertoire,and better-preserved genome integrity. Our data identify proliferative stress as a driver of HSPC dysfunction with fundamental implications for designing more effective and safer gene correction strategies for clinical applications. View Publication

Global dissemination of SARS-CoV-2 Omicron sublineages has provided a sufficient opportunity for natural selection,thus enabling beneficial mutations to emerge. Characterisation of these mutations uncovers the underlying machinery responsible for the fast transmission of Omicron variants and guides vaccine development for combating the COVID-19 pandemic. Through systematic bioinformatics analysis of 496,606 sequences of Omicron variants,we obtained 40 amino acid substitutions that occurred with high frequency in the S protein. Utilising pseudoviruses and a trans -complementation system of SARS-CoV-2,we identified the effect of high-frequency mutations on viral infectivity and elucidated the molecular mechanisms. Finally,we evaluated the impact of a key emerging mutation on the immune protection induced by the SARS-CoV-2 VLP mRNA vaccine in a murine model. We identified a proline-to-leucine substitution at the 1263rd residue of the Spike protein,and upon investigating the relative frequencies across multiple Omicron sublineages,we found a trend of increasing frequency for P1263L. The substitution significantly enhances the capacity for S-mediated viral entry and improves the immunogenicity of a virus-like particle mRNA vaccine. Mechanistic studies showed that this mutation is located in the FERM binding motif of the cytoplasmic tail and impairs the interaction between the S protein and the Ezrin/Radixin/Moesin proteins. Additionally,this mutation facilitates the incorporation of S proteins into SARS-CoV-2 virions. This study offers mechanistic insight into the constantly increasing transmissibility of SARS-CoV-2 Omicron variants and provides a meaningful optimisation strategy for vaccine development against SARS-CoV-2. This study was supported by grants from the National Key Research and Development Plan of China (2021YFC2302405,2022YFC2303200,2021YFC2300200 and 2022YFC2303400),the National Natural Science Foundation of China (32188101,32200772,82422049,82241082,32270182,82372254,82271872,82341046,32100755 and 82102389),Shenzhen Medical Research Fund (B2404002,A2303036),the Shenzhen Bay Laboratory Startup Fund (21330111),Shenzhen San-Ming Project for Prevention and Research on Vector-borne Diseases (SZSM202211023),Yunnan Provincial Science and Technology Project at Southwest United Graduate School (202302AO370010). The New Cornerstone Science Foundation through the New Cornerstone Investigator Program,and the Xplorer Prize from Tencent Foundation. View Publication