技术资料

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

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

Reduction of adult hippocampal neurogenesis is an early critical event in Alzheimer’s disease (AD),contributing to progressive memory loss and cognitive decline. Reduced levels of the nucleoporin 153 (Nup153),a key epigenetic regulator of NSC stemness,characterize the neural stem cells isolated from a mouse model of AD (3×Tg) (AD-NSCs) and determine their altered plasticity and gene expression. Nup153-regulated mechanisms contributing to NSC function were investigated: (1) in cultured NSCs isolated from AD and wild type (WT) mice by proteomics; (2) in vivo by lentiviral-mediated delivery of Nup153 or GFP in the hippocampus of AD and control mice analyzing neurogenesis and cognitive function; (3) in human iPSC-derived brain organoids obtained from AD patients and control subjects as a model of neurodevelopment. Proteomic approach identified Nup153 interactors in WT- and AD-NSCs potentially implicated in neurogenesis regulation. Gene ontology (GO) analysis showed that Nup153-bound proteins in WT-NSCs were involved in RNA metabolism,nuclear import and epigenetic mechanisms. Nup153-bound proteins in AD-NSCs were involved in pathways of neurodegeneration,mitochondrial dysfunction,proteasomal processing and RNA degradation. Furthermore,recovery of Nup153 levels in AD-NSCs reduced the levels of oxidative stress markers and recovered proteasomal activity. Lentiviral-mediated delivery of Nup153 in the hippocampal niche of AD mice increased the proliferation of early progenitors,marked by BrdU/DCX and BrdU/PSANCAM positivity and,later,the integration of differentiating neurons in the cell granule layer (BrdU/NeuN + cells) compared with GFP-injected AD mice. Consistently,Nup153-injected AD mice showed an improvement of cognitive performance in comparison to AD-GFP mice at 1 month after virus delivery assessed by Morris Water Maze. To validate the role of Nup153 in neurogenesis we took advantage of brain organoids derived from AD-iPSCs characterized by fewer neuroepithelial progenitor loops and reduced differentiation areas. The upregulation of Nup153 in AD organoids recovered the formation of neural-like tubes and differentiation. Our data suggest that the positive effect of Nup153 on neurogenesis is based on a complex regulatory network orchestrated by Nup153 and that this protein is a valuable disease target. The online version contains supplementary material available at 10.1186/s13287-024-03805-1. View Publication

Immune checkpoint blockade (ICB) has made remarkable achievements,but newly identified armored and cold tumors cannot respond to ICB therapy. The high prevalence of concomitant medications has huge impact on immunotherapeutic responses,but the clinical effects on the therapeutic outcome of armored and cold tumors are still unclear. In this research,using large-scale transcriptomics datasets,the expression and potential biological functions of angiotensin II receptor 1 (AGTR1),the target of angiotensin receptor blocker (ARB),were investigated. Next,the roles of ARB in tumor cells and tumor microenvironment cells were defined by a series of in vitro and in vivo assays. In addition,the clinical impacts of ARB on ICB therapy were assessed by multicenter cohorts and meta-analysis. AGTR1 was overexpressed in armored and cold tumors and associated with poor response to ICB therapy. ARB,the inhibitor for AGTR1,only suppressed the aggressiveness of tumor cells with high AGTR1 expression,which accounted for a very small proportion. Further analysis revealed that AGTR1 was always highly expressed in cancer-associated fibroblasts (CAFs) and ARB inhibited type I collagen expression in CAFs by suppressing the RhoA-YAP axis. Moreover,ARB could also drastically reverse the phenotype of armored and cold to soft and hot in vivo,leading to a higher response to ICB therapy. In addition,both our in-house cohorts and meta-analysis further supported the idea that ARB can significantly enhance ICB efficacy. Overall,we identify AGTR1 as a novel target in armored and cold tumors and demonstrate the improved therapeutic efficacy of ICB in combination with ARB. These findings could provide novel clinical insight into how to treat patients with refractory armored and cold tumors. View Publication

Dimethylsulfoxide (DMSO) has conventionally been used for cell cryopreservation both in research and in clinical applications,but has long-term cytotoxic effects. Trehalose,a natural disaccharide,has been proposed as a non-toxic cryoprotectant. However,the lack of specific cell membrane transporter receptors inhibits transmembrane transport and severely limits its cryoprotective capability. This research presents a method to successfully deliver trehalose into mesenchymal stem cells (MSCs) using ultrasound in the presence of microbubbles. The optimised trehalose concentration was shown to be able to not only preserve membrane integrity and cell viability but also the multipotency of MSCs,which are essential for stem cell therapy. Confocal imaging revealed that rhodamine-labelled trehalose was transported into cells rather than simply attached to the membrane. Additionally,the membranes were successfully preserved in lyophilised cells. This study demonstrates that ultrasonication with microbubbles facilitated trehalose delivery,offering promising cryoprotective capability without the cytotoxicity associated with DMSO-based methods. Subject terms: Membrane biophysics,Biomedical engineering View Publication

In recent years,Raman spectroscopy has garnered growing interest in the field of biomedical research. It offers a non-invasive and label-free approach to defining the molecular fingerprint of immune cells. We utilized Raman spectroscopy on optically trapped immune cells to investigate their molecular compositions. While numerous immune cell types have been studied in the past,the characterization of living human CD3/CD28-stimulated T cell subsets remains incomplete. In this study,we demonstrate the capability of Raman spectroscopy to readily distinguish between naïve and stimulated CD4 and CD8 cells. Additionally,we compared these cells with monocytes and discovered remarkable similarities between stimulated T cells and monocytes. This paper contributes to expanding our knowledge of Raman spectroscopy of immune cells and serves as a launching point for future clinical applications. View Publication

A hexanucleotide GGGGCC repeat expansion in the C9orf72 gene is the most frequent genetic cause of amyotrophic lateral sclerosis (ALS) and frontal temporal dementia (FTD). C9orf72 repeat expansions are currently identified with long-range PCR or Southern blot for clinical and research purposes,but these methods lack accuracy and sensitivity. The GC-rich and repetitive content of the region cannot be amplified by PCR,which leads traditional sequencing approaches to fail. We turned instead to PacBio single-molecule sequencing to detect and size the C9orf72 repeat expansion without amplification. We isolated high molecular weight genomic DNA from patient-derived iPSCs of varying repeat lengths and then excised the region containing the C9orf72 repeat expansion from naked DNA with a CRISPR/Cas9 system. We added adapters to the cut ends,capturing the target region for sequencing on PacBio’s Sequel,Sequel II,or Sequel IIe. This approach enriches the C9orf72 repeat region without amplification and allows the repeat expansion to be consistently and accurately sized,even for repeats in the thousands. Key features • This protocol is adapted from PacBio’s previous “no-amp targeted sequencing utilizing the CRISPR-Cas9 system.” • Optimized for sizing C9orf72 repeat expansions in patient-derived iPSCs and applicable to DNA from any cell type,blood,or tissue. • Requires high molecular weight naked DNA. • Compatible with Sequel I and II but not Revio. View Publication

High-grade serous ovarian cancer remains a poorly understood disease with a high mortality rate. Although most patients respond to cytotoxic therapies,a majority will experience recurrence. This may be due to a minority of drug-resistant cancer stem-like cells (CSC) that survive chemotherapy and are capable of repopulating heterogeneous tumors. It remains unclear how CSCs are supported in the tumor microenvironment (TME) particularly during chemotherapy exposure. Tumor-associated macrophages (TAM) make up half of the immune population of the ovarian TME and are known to support CSCs and contribute to cancer progression. TAMs are plastic cells that alter their phenotype in response to environmental stimuli and thus may influence CSC maintenance during chemotherapy. Given the plasticity of TAMs,we studied the effects of carboplatin on macrophage phenotypes using both THP1- and peripheral blood mononuclear cell (PBMC)–derived macrophages and whether this supports CSCs and ovarian cancer progression following treatment. We found that carboplatin exposure induces an M1-like proinflammatory phenotype that promotes SOX2 expression,spheroid formation,and CD117 + ovarian CSCs,and that macrophage-secreted CCL2/MCP-1 is at least partially responsible for this effect. Depletion of TAMs during carboplatin exposure results in fewer CSCs and prolonged survival in a xenograft model of ovarian cancer. This study supports a role for platinum-based chemotherapies in promoting a transient proinflammatory M1-like TAM that enriches for CSCs during treatment. Improving our understanding of TME responses to cytotoxic drugs and identifying novel mechanisms of CSC maintenance will enable the development of better therapeutic strategies for high-grade serous ovarian cancer. Significance: We show that chemotherapy enhances proinflammatory macrophage phenotypes that correlate with ovarian cancer progression. Given that macrophages are the most prominent immune cell within these tumors,this work provides the foundation for future translational studies targeting specific macrophage populations during chemotherapy,a promising approach to prevent relapse in ovarian cancer. View Publication

A hexanucleotide repeat expansion (HRE) in C9ORF72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Human brain imaging and experimental studies indicate early changes in brain structure and connectivity in C9-ALS/FTD,even before symptom onset. Because these early disease phenotypes remain incompletely understood,we generated iPSC-derived cerebral organoid models from C9-ALS/FTD patients,presymptomatic C9ORF72-HRE (C9-HRE) carriers,and controls. Our work revealed the presence of all three C9-HRE-related molecular pathologies and developmental stage-dependent size phenotypes in cerebral organoids from C9-ALS/FTD patients. In addition,single-cell RNA sequencing identified changes in cell type abundance and distribution in C9-ALS/FTD organoids,including a reduction in the number of deep layer cortical neurons and the distribution of neural progenitors. Further,molecular and cellular analyses and patch-clamp electrophysiology detected various changes in synapse structure and function. Intriguingly,organoids from all presymptomatic C9-HRE carriers displayed C9-HRE molecular pathology,whereas the extent to which more downstream cellular defects,as found in C9-ALS/FTD models,were detected varied for the different presymptomatic C9-HRE cases. Together,these results unveil early changes in 3D human brain tissue organization and synaptic connectivity in C9-ALS/FTD that likely constitute initial pathologies crucial for understanding disease onset and the design of therapeutic strategies. The online version contains supplementary material available at 10.1186/s40478-024-01857-1. View Publication

Paulownin,a natural compound derived from Paulownia tomentosa wood,exhibits various physiological functions,including anti-bacterial and anti-fungal effects. However,the impact of paulownin on natural killer (NK) cell immune activity remains largely unknown. In this study,we investigated the effect of paulownin on NK cell activity both in vitro and in vivo,and explored its potential mechanisms. NK-92 cells were used for in vitro experiments and a BALB/c mouse model with B16F10 cells injected subcutaneously were used for in vivo anti-tumor analysis. We found that paulownin enhanced the cytolytic activity of NK-92 cells against leukemia,human colon,and human lung cancer cell lines. Paulownin treatment increased the expression of the degranulation marker protein CD107a and cytolytic granules,including granzyme B and perforin in NK-92 cells. Moreover,these enhancements of cytotoxicity and the expression of cytolytic granules induced by paulownin were also observed in human primary NK cells. Signaling studies showed that paulownin promoted the phosphorylation of JNK. The increased perforin expression and elevated cytotoxic activity induced by paulownin were effectively inhibited by pre-treatment with a JNK inhibitor. In vivo studies demonstrated that the administration of paulownin suppressed the growth of B16F10 melanoma cells allografted into mice. Paulownin administration promoted the activation of NK cells in the spleen of mice,resulting in enhanced cytotoxicity against YAC-1 cells. Moreover,the anti-tumor effects of paulownin were reduced upon the depletion of NK cells. Therefore,these results suggest that paulownin enhances NK cell cytotoxicity by activating the JNK signaling pathway and provide significant implications for developing new strategies for cancer immunotherapy. View Publication