技术资料

Alongside their well-established role in hemostasis,platelets are key modulators of immune cell function. This is particularly the case for macrophages,as platelets can either promote or dampen macrophage activation in a context-specific manner. Whilst the role of platelets in modulating classical (M1) macrophage activation following bacterial challenge is relatively well understood,whether platelets control other macrophage responses is less clear. We investigated the role of platelets in type 2 inflammation using a mouse model of chronic schistosomiasis. Schistosome infection caused thrombocytopenia which was not fully reversed after drug-induced parasite death. Reduced platelet levels in infection were coincident with lower levels of systemic TPO and extensive liver damage caused by parasite eggs. Infection also reduced the ploidy and size (but not number) of bone marrow megakaryocytes,which was associated with reduced platelet output. We show schistosome infection accelerated platelet clearance and promoted the formation of platelet-leukocyte aggregates. This was particularly the case for liver macrophages and monocytes. Phenotypic analysis shows that platelet-associated liver macrophages had a distinct activation phenotype that included elevated expression of the alternative (M2) activation marker RELMα. Despite this,in vitro studies indicated that platelets do not directly promote macrophage alternative activation. Similarly,whilst in vivo pharmacological treatment with a TPO mimetic enhanced platelet numbers and platelet-leukocyte aggregates,this did not alter macrophage phenotype. Conversely,antibody-mediated depletion of platelets or use of platelet-deficient mice both led to extensive bleeding following infection which impacted host survival. Together,these data indicate that whilst platelets are essential to prevent excessive disease pathology in schistosomiasis,they have a more nuanced role in myeloid cell activation and type 2 immune responses. Author summaryPlatelets are the second most abundant blood cell and are best known for their role in stopping bleeding after blood vessel damage. More recent studies have revealed another important function of platelets is their ability to control immune cell activation. Here,we investigate the role of platelets in immune responses to schistosomes,parasitic worms that cause the disease schistosomiasis that affects hundreds of millions worldwide. Schistosome worms live in our blood vessels and release large numbers of eggs that must exit the blood and move through our tissues to exit the body for onward transmission. However,a large number of eggs become trapped in different organs causing inflammation and disease pathology. We find that schistosome infection reduces the numbers of platelets in the blood of laboratory mice. Platelets are taken up by liver macrophages,and whilst these macrophages have a distinct activation profile compared to other cells,platelets themselves do not cause these changes. However,platelets are essential to survive schistosomiasis due to excessive bleeding in their absence. Together,this work shows that platelets are key to surviving schistosome infection but this reflects more their role in preventing bleeding rather than controlling immune cell function. View Publication

Background: Biliary atresia (BA) is the most prevalent serious neonatal biliary obstructive disorder and is a complex multifactorial liver disorder. Genome-wide association studies have identified Adducin 3 (ADD3) as a BA susceptibility gene but the mechanisms involved in disease causation and progression remain unclear. Methods: ADD3 knockout human pluripotent stem cells were differentiated into cholangiocyte organoids to assess the effect of ADD3 deletion on biliary development in vitro. Add3 deletion in rhesus rotavirus (RRV)-induced experimental BA mice were employed as the in vivo model to address the impact of reduced Add3 expression on BA pathogenesis. Findings: ADD3 knockout organoids displayed defective cholangiocyte differentiation,failure in the recruitment of βII-spectrin to the cell membrane,abnormal primary cilia development,reduced expression of tight junction proteins,lower transepithelial electrical resistance (TEER) and increased paracellular permeability. Statistical significantly reduced tight junction (TJ) proteins expression and lower TEER in Add3+/− and Add3−/− liver tissue-derived cholangiocytes were observed. Reduced number of TJs and enlarged paracellular spaces without any detectable TJ were detected in the intra-hepatic bile ducts of Add3+/− and Add3−/− livers. A statistical significantly higher incidence and a more advanced form of BA with statistical significantly higher serum bilirubin,liver necrosis and fibrosis,and accumulation of macrophages and activated hepatic stellate cells were observed in Add3 knockout BA mice as compared to wild-type BA mice. Interpretation: Dysregulated ADD3 expression caused an abnormal development and impaired barrier function of cholangiocytes,and the resultant increase in bile duct permeability rendered the foetus/neonate susceptible to a more severe injury response to an external insult. The findings support the hypothetical pathogenic model of genetic susceptibility genes being involved in hepatobiliary development/structure,and the perturbed embryogenesis of the biliary tree and its disrupt integrity increase the host susceptibility to biliary injury and BA. View Publication

Eosinophils are major effector cells in type 2 immune responses,contributing to host defense and allergic diseases. They also contribute to maintaining tissue homeostasis by regulating various immune cell types,including neutrophils. Here we show that eosinophils directly associate with neutrophils in the lungs of asthma-induced mice. Eosinophil-specific deficiency of the short-chain fatty acid receptor,GPR43,results in hyperactivation of eosinophils and increases the expression of neutrophil chemoattractants and PECAM-1,thereby enhancing the interaction between eosinophils and neutrophils. This interaction exposes neutrophils to eosinophil-derived IL-4 and GM-CSF,which induce the conversion of conventional neutrophils into more pathogenic,Siglec-Fhi neutrophils capable of enhancing Th17 cell differentiation and aggravating asthma symptoms in mouse models. Our results thus implicate GPR43 as a critical regulator of eosinophils,and describe eosinophil-mediated modulation of neutrophil differentiation and function. Eosinophils contribute to type 2 immunity,but their interaction with neutrophils in this context is incompletely understood. Here the authors use mouse asthma models and in vitro culture to show that eosinophil-specific deficiency of GPR43 promotes Siglec-Fhi neutrophil differentiation and downstream induction of Th17 to aggravate lung inflammation and asthma. View Publication

In dynamic light microscopy applications,imaging specimens from multiple angles while maintaining controlled temperature conditions is crucial for comprehensive and accurate analysis. To address these challenges,we present iCAT,an open-source multifunctional accessory designed to enhance light microscopy. It enables specimen rotation along the axial plane,incorporates built-in modules for precise temperature control,features an integrated LED,and includes a camera for real-time specimen monitoring. It can be easily 3D-printed and assembled using readily available electrical components. Combined with any up-right microscope,this versatile device allows researchers to capture detailed images and videos of organoid cultures and live or fixed specimens,such as C. elegans,zebrafish,drosophila,or mouse embryos. The potential applications of iCAT in investigating dynamic cellular processes and complex developmental phenomena are vast,inspiring researchers to explore its possibilities and push the boundaries of biological research. iCAT,an open-source,3D-printable microscopy accessory,enables axial specimen rotation,temperature control,and live monitoring for high-resolution imaging of organoids and diverse model organisms. View Publication

USP30,a ubiquitin‐specific protease,primarily characterized as a mitochondrial deubiquitinase regulating mitophagy,has not been previously reported to have nuclear functions. In this study,we demonstrate that USP30 is present in both mitochondrial and nuclear compartments. Nutrient deprivation triggers USP30 nuclear translocation via an N‐terminal nuclear localization signal (NLS),mediated through suppression of mTORC1‐dependent phosphorylation at serine 104,a modification constraining nuclear entry. Nuclear USP30 acts as a tumor suppressor by inhibiting cancer stemness and chemoresistance in triple‐negative breast cancer (TNBC) cells. Mechanistically,USP30 directly interacts with and deubiquitinates the transcription factor TCF/LEF1 at K379 and K382 residues,disrupting recruitment of CBP/P300 co‐activators to the β‐catenin/LEF1 complex. This abolishes β‐catenin/LEF1 transactivation and suppresses WNT signaling. Clinically,USP30 is downregulated in TNBC and cancer stem cells (CSCs),with notably reduced nuclear levels in cancer tissues. Overexpression of nuclear USP30 markedly reduces lung metastatic burden in TNBC mouse models. These findings uncover a novel role for nuclear USP30 in regulating cancer stemness and suggest that targeting the dynamic relocalization of USP30 from mitochondria to the nucleus could offer new therapeutic strategies for breast cancer metastasis. View Publication

Silencing remains a significant challenge for exogenous gene expression,limiting both the penetrance and expressivity of transgenes. In particular,silencing of Cas9 expression is a major technical limitation for many gene editing and CRISPR screening applications. Here,we demonstrate that including introns in Cas9 expression cassettes significantly reduces silencing across multiple cell lines. Notably,the incorporation of an intron into a CRISPRa construct results in reduced silencing,increased expression levels,and markedly enhanced activation of target genes. We investigate diverse intron sequences and discover that T-rich introns over 2 kb confer the greatest protection against silencing. In addition,we find that introns can work synergistically with chromatin opening elements to further mitigate silencing,suggesting regulatory mechanisms are acting at both the DNA and RNA level to silence exogenous genes. Our work highlights the potential of introns to optimize genetic constructs for enhanced expression and improved cellular engineering requiring constitutive expression of large transgenes. Silencing of transgenes such as Cas9 limits gene editing and CRISPRa applications. Here,the authors show that adding intronic sequences reduces silencing and boosts transgene expression,enabling improved CRISPRa-mediated gene activation and more stable expression of the transgene over time. View Publication

How the neuroectoderm-derived eye field breaks symmetry to specify iris muscle is not well understood. Recent studies have begun to transcriptionally characterize mouse iris muscle; however,little is known about the transcriptional foundation of human iris development. Human pluripotent stem cells (hPSCs) enable the study of iris muscle specification. Here we compare iris smooth muscle from native adult iris tissues to evaluate successful specification of iris muscle from hPSC lines. We utilize a previously published eye-like organoid protocol that specified cells of the eye field to also generate iris muscle. We describe a population transcriptionally similar to native iris and describe an iris muscle gene signature. Human iris muscle not only contains pigment,but also expresses pigment synthesis genes and is responsive to acetylcholine. Integration of single-cell RNA-seq datasets confirm the similarity between the iris muscle to the adult iris,establishing the usefulness of the model in studying neuroectoderm-derived iris muscle specification,and related diseases. Single-cell RNA sequencing reveals that iris muscle,derived from neuroectoderm,can form in stem cell–derived eye organoids – enabling the modelling of iris muscle pathologies like aniridia and proliferative vitreoretinopathy. View Publication

Background: Acute Lung Injury (ALI) and its most severe form,Acute Respiratory Distress Syndrome (ARDS),are critical pulmonary conditions characterized by life-threatening acute hypoxic respiratory failure,affecting over three million individuals globally each year. ALI involves alveolar inflammation and disruption of the alveolar-capillary barrier,primarily driven by neutrophil infiltration and the release of inflammatory mediators. In our previous study using a lipopolysaccharide (LPS)-induced mouse model of ALI,we demonstrated that C6,a peptide inhibitor of voltage-gated proton channels (Hv1),ameliorates lung injury,identifying Hv1 as a potential therapeutic target. However,(i) whether the anti-inflammatory effects of C6 are translatable to a clinically relevant live bacterial infection model,and (ii) the molecular mechanisms underlying these anti-inflammatory effects,remain unknown,and are a crucial next step towards targeted rational drug development. Methods: To induce ALI,we used an intratracheal Pseudomonas aeruginosa infection model,a gram-negative bacterium relevant in ventilated and immunocompromised patients. A separate group of infected mice also received intravenous treatment with C6 (4 mg/kg). Lung injury severity was evaluated using histopathological analysis. Bronchoalveolar lavage (BAL) fluid was collected to quantify neutrophil infiltration and proinflammatory cytokines concentrations. In addition,reactive oxygen species (ROS) production and intracellular calcium levels in BAL neutrophils were measured. RNA sequencing of BAL neutrophils was conducted to assess C6-induced transcriptional changes. Key findings were validated in vitro using human neutrophils. Results: C6 mitigates P. aeruginosa-induced ALI in mice by reducing neutrophil infiltration into the alveolar space by ~ 86%,improving lung injury scores,decreasing BAL fluid proinflammatory cytokine levels,and suppressing neutrophil ROS production and intracellular calcium levels. RNA sequencing of BAL neutrophils revealed 51 downregulated genes,including key regulators of neutrophil migration,cytokine release,and ROS production; only three genes were upregulated and they also have roles in neutrophil immune defense. In human neutrophils,C6 similarly inhibited chemotaxis and reduced ROS and cytokine release,and calcium influx. Conclusions: Targeting Hv1 with C6 effectively protects against P. aeruginosa-induced ALI by limiting neutrophil recruitment and activation. These findings establish C6 as a promising therapeutic candidate against infectious ALI and provide important mechanistic insights into its immunomodulatory effects on neutrophils. View Publication

Acute myeloid leukemia (AML) is primarily driven by leukemic stem cells (LSCs),the main cause of relapse and therapy resistance. Here,we discover that LSCs are predominantly small and mechanically soft. These mechanical properties enable their selective isolation using microfluidic chips. Single-cell RNA-sequencing of primary human AML bone marrow identifies enrichment of LSCs within the FSClow ALDH1A1+ subpopulation,which exhibits long-term stemness in functional assays. Notably,inhibiting ALDH1A1 in these cells promotes F-actin polymerization and increases cellular stiffness,reducing their stemness while enhancing their susceptibility to natural killer (NK) cell-mediated cytotoxicity. In AML patient-derived xenograft models,the combination of ALDH1A1 inhibition with NK cell therapy markedly suppresses leukemia progression. These findings suggest that targeting the mechanical properties of LSC offers a promising strategy to overcome AML treatment resistance,providing insights into stem cell mechanobiology and paving the way for combining targeted therapies with immunotherapy to improve clinical outcomes. Leukemic stem cells (LSCs) drive relapse and therapy resistance in acute myeloid leukemia (AML). Here,the authors show that increasing the stiffness of LSCs reduces their stemness and enhances their susceptibility to natural killer cell-mediated immunotherapy in AML. View Publication

Cutaneous tuberculosis (CTB) is an infectious disease highly associated with extracellular matrix remodeling and granuloma-driven fibrosis. Fibroblasts play crucial roles in this fibrotic process,but their specific roles in Mycobacterium tuberculosis (Mtb) skin infections remain unclear due to the lack of proper in vitro models. Here,we demonstrate that skin organoids (SKOs) derived from human induced pluripotent stem cells can model CTB infected by Mtb. Single-cell RNA analyses reveal an increase in fibroblasts,upregulation of genes involved in collagen synthesis,and enhanced collagen degradation induced by MMP2 and MMP14 in Mtb-infected SKOs. This is accompanied by the destruction of nerve cells and adipocytes. Importantly,the onset of fibrosis in Mtb-infected SKOs is dependent on the activation of the PI3K-AKT signaling pathway and transcription factor AP1 in fibroblasts. Pharmacological inhibition of PI3K-AKT and AP1 alleviates fibrosis and collagen deposition. Our findings have uncovered distinct alterations in cell populations during Mtb-induced skin fibrosis,highlighting the crucial roles of PI3K-AKT and AP1. The study demonstrates the utility of SKOs for investigating CTB pathogenesis and evaluating potential antifibrotic treatments. Cutaneous tuberculosis is an infectious disease associated with extracellular matrix remodeling and granuloma-driven fibrosis. Here,the authors present an in vitro model of this disease using skin organoids infected with Mycobacterium tuberculosis,and describe infection-induced alterations in specific pathways and cell populations. View Publication

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe inherited skin disorder caused by mutations in COL7A1. Patient-derived induced pluripotent stem cells (iPSCs) enable the personalized study of RDEB pathogenesis and potential therapies. However,current skin cell differentiation protocols via 2D culture perform suboptimally when applied to engineered 3D skin constructs (ESC). Here,we present an approach to source fibroblasts (iFBs) and keratinocytes (iKCs) from iPSC-derived skin organoids using an optimized differentiation protocol,and utilize them to engineer ESCs modeling wild-type and RDEB phenotypes. The resulting iPSC-derived skin cells display marker expression consistent with primary counterparts and produce ESCs exhibiting significant extracellular matrix remodeling,protein deposition,and epidermal differentiation. RDEB constructs recapitulated hallmark disease features,including absence of collagen VII and reduced iFB proliferation. This work establishes a robust and scalable strategy for generating physiologically-relevant,iPSC-derived skin constructs,offering a powerful model for studying RDEB mechanisms and advancing personalized regenerative medicine. View Publication

Systemic sclerosis (SSc) is an autoimmune disease marked by fibrosis and extensive autoantibody production. Although B-cell depletion with rituximab (RTX) has shown clinical benefit,predictive biomarkers of response remain elusive. Here,we apply proteome-wide autoantibody screening using wet protein arrays covering 13,455 human antigens in serum samples from participants of the randomized trial of RTX. We identify a significant elevation in the total autoantibody levels in SSc compared to healthy controls,with greater reductions post-treatment observed in RTX high responders than in low responders. A stepwise selection highlights 88 clinically relevant autoantibodies,including those targeting G protein-coupled receptors. Among them,anti-C-C motif chemokine receptor 8 (CCR8) autoantibodies are functionally validated by cell-based assays using CCR8-overexpressing HEK293 cells. Furthermore,in a bleomycin-induced mouse model,anti-CCR8 antibody administration exacerbates dermal fibrosis and modifies immune cell infiltration. Although external validation with multiple comparison adjustment is further required,these findings reveal an autoantibody signature associated with therapeutic response and pathogenic potential in SSc,providing a foundation for precision immunotherapy and mechanistic insights into disease progression. B-cell depletion benefits systemic sclerosis,but predictive biomarkers remain limited. The authors here map autoantibody profiles using proteome-wide screening,identify C-C motif chemokine receptor 8-targeting autoantibodies with functional impact,suggesting novel pathophysiology and precision therapy targets. View Publication