技术资料

Stargardt disease (STGD),predominantly caused by mutations in the ABCA4 gene,is a leading cause of inherited retinal degeneration. Although several lines of mice expressing disease-causing variants have been produced,mice due to the lack of macular may not be the perfect model to mimic the characteristics of STGD. To address this knowledge gap,we generated retinal organoids from patient-derived induced pluripotent stem cells (iPSCs) harboring ABCA4 mutations and performed biological validation. The generated retinal organoids were subjected to single-cell RNA sequencing (scRNA-seq) at major developmental stages (40,90,150,200,and 260 days),and we additionally compared the transcriptomics with our recently published control retinal organoids to further confirm the reliability of the dataset. By using iPSCs carrying most common variant in Chinese STGD patients,the dataset not only provides a powerful resource for studying STGD,but also offers novels insight into the developmental mechanisms underlying ABCA4-associated pathological changes in the retinal organoid system. View Publication

SummaryGlioblastomas are the most common malignant brain tumors in adults; they are highly aggressive and heterogeneous and show a high degree of plasticity. Here,we show that methyltransferase-like 7B (METTL7B) is an essential regulator of lineage specification in glioblastoma,with an impact on both tumor size and invasiveness. Single-cell transcriptomic analysis of these tumors and of cerebral organoids derived from expanded potential stem cells overexpressing METTL7B reveal a regulatory role for the gene in the neural stem cell-to-astrocyte differentiation trajectory. Mechanistically,METTL7B downregulates the expression of key neuronal differentiation players,including SALL2,via post-translational modifications of histone marks. Graphical abstract Highlights•METTL7B is highly expressed in human glioblastoma stem cells•METTL7B regulates tumor size and invasiveness in an in vivo xenograft model•METTL7B controls the neural stem cell-to-astrocyte differentiation trajectory•METTL7B regulates SALL2 expression via H3K27me3 modulation Constantinou et al. identify METTL7B as an essential regulator of lineage specification and a modulator of the expression of the transcription factor SALL2 with wide-ranging impacts on invasion and tumor growth in glioblastoma. View Publication

ABSTRACTHuman induced pluripotent stem cells (iPSCs) are an invaluable endless cell source for generating various therapeutic cells and tissues. However,their differentiation into specific cell lineages,such as definitive endoderm (DE) and pancreatic progenitor (PP),often suffers from poor reproducibility,due partially to their pluripotency. In this work,we investigated the impact of iPSC confluency during cell self?renewal and seeding density on cell metabolic activity,glycolysis to oxidative phosphorylation shift,and differentiation potential toward DE and PP lineages. Our findings demonstrated that cell seeding strategy influences cellular metabolic activity and the robustness of iPSC differentiation. iPSCs maintained at higher seeding density exhibited lower initial oxygen consumption rate (OCR) and metabolic activity. There is an optimal seeding density to ensure sufficient oxygen consumption during differentiation and to yield high expression of SOX17 in the DE lineage and high PDX1/NKX6.1 dual?positive cells in PPs. Interestingly,we found that cell confluency at the time of harvest has less impact on the efficacy of pancreatic lineage formation or metabolic activity. This study sheds light on the interplay between metabolic activity and iPSC lineage specification,offering new insights into the robustness of iPSC self?renewal and differentiation for creating human tissues. Graphical Abstract and Lay SummaryHuman induced pluripotent stem cell (iPSC) differentiation into specific cell lineages often shows poor reproducibility due to cell pluripotency. This study demonstrated impact of iPSC seeding strategy on metabolic activity and differentiation potential,offering new insights into the robustness of iPSC self?renewal and differentiation for creating human tissues. View Publication

Biallelic mutations in PIGK cause GPI biosynthesis defect 22 (GPIBD22),characterized with developmental delay,hypotonia,and cerebellar atrophy. The understanding of the underlying causes is limited due to the lack of suitable disease models. To address this gap,we generated a mouse model with PIGK deficits,specifically in Purkinje cells (Pcp2-cko) and an induced pluripotent stem cell (iPSC) model using the c.87dupT mutant (KI) found in GPIBD22 patients. Pcp2-cko mice demonstrated cerebellar atrophy,ataxia and progressive Purkinje cells loss which were accompanied by increased apoptosis and neuroinflammation. Similarly,KI iPSCs exhibited increased apoptosis and accelerated neural rosette formation,indicating that PIGK defects could impact early neural differentiation that confirmed by the RNA-Seq results of neural progenitor cells (NPCs). The increased apoptosis and accelerated NPC differentiation in KI iPSCs are associated with excessive unfolded protein response (UPR) pathway activation,and can be rescued by UPR pathway inhibitor. Our study reveals potential pathogenic mechanism of GPIBD22 and providing new insights into the therapeutic strategy for GPIBD. View Publication

A large number of synaptic proteins have been recurrently associated with complex brain disorders. One of these proteins,the Traf and Nck interacting kinase (TNIK),is a postsynaptic density (PSD) signaling hub,with many variants reported in neurodevelopmental disorder (NDD) and psychiatric disease. While rodent models of TNIK dysfunction have abnormal spontaneous synaptic activity and cognitive impairment,the role of mutations found in patients with TNIK protein deficiency and TNIK protein kinase activity during early stages of neuronal and synapse development has not been characterized. Here,using hiPSC-derived excitatory neurons,we show that TNIK mutations dysregulate neuronal activity in human immature synapses. Moreover,the lack of TNIK protein kinase activity impairs MAPK signaling and protein phosphorylation in structural components of the PSD. We show that the TNIK interactome is enriched in NDD risk factors and TNIK lack of function disrupts signaling networks and protein interactors associated with NDD that only partially overlap to mature mouse synapses,suggesting a differential role of TNIK in immature synapsis in NDD. View Publication

Differentiation approaches to obtain mesenchymal stem cells (MSCs) have gradually developed over the last few decades. The problem is that different protocols give different MSC types,making further research difficult. Here,we tried three different approaches to differentiate embryonic stem cells (ESCs) from early mesoderm to MSCs using serum-containing or xeno-free differentiation medium and observed differences in the cells’ morphology,doubling rate,ability to form colonies,surface marker analysis,and multilineage differentiation potential of the obtained cell lines. We concluded that the xeno-free medium best fits the criteria of MSCs’ morphology,growth kinetics,and surface marker characterization. In contrast,the serum-containing medium gives better potential for further MSC differentiation into osteogenic,chondrogenic,and adipogenic lineages. View Publication

Simple SummaryAtypical teratoid rhabdoid tumors (ATRTs) and diffuse intrinsic pontine gliomas (DIPGs) are lethal pediatric brain tumors that can resist chemotherapy and be influenced by their microenvironment. Astrocytes are the key components of the brain tumor microenvironment and can support tumor growth. We investigated the effects of astrocytes on cisplatin sensitivity in pediatric brain cancer cells. The crosstalk between astrocytes and cancer cells activated astrocytes and promoted cancer cell proliferation. Moreover,the tumor cells expressed elevated levels of drug resistance genes in the presence of astrocytes. In conclusion,astrocytes can significantly improve the growth of these tumor cells and modulate their chemosensitivity,highlighting their role in therapeutic resistance. AbstractBackground: ATRTs and DIPGs are deadly pediatric brain tumors with poor prognosis. These tumors can develop resistance to chemotherapies,which may be significantly influenced by their microenvironment. Since astrocytes are the most abundant glial cell type in the brain microenvironment and may support tumor growth and chemoresistance,this study investigated the effects of induced pluripotent stem cell-derived astrocytes (iPSC-astrocytes) on cisplatin sensitivity in CHLA-05-ATRT and SF8628 (DIPG) cells. iPSCs provide an unlimited and standardized source of nascent astrocytes,which enables modeling the interaction between childhood brain tumor cells and iPSC-astrocytes within a controlled coculture system. Methods: To study the effects on tumor growth,the iPSC-astrocytes were cocultured with tumor cells. Additionally,the tumor cells were exposed to various concentrations of cisplatin to evaluate their chemosensitivity in the presence of astrocytes. Results: The paracrine interaction of iPSC-astrocytes with tumor cells upregulated astrocyte activation markers GFAP and STAT3 and promoted tumor cell proliferation. Moreover,the cisplatin treatment significantly decreased the viability of CHLA-05-ATRT and SF8628 cells. However,tumor cells exhibited reduced sensitivity to cisplatin in the coculture with iPSC-astrocytes. During cisplatin treatment,DIPG cells in particular showed upregulation of resistance markers,ERK1,STAT3,and MTDH,which are associated with enhanced proliferation and invasion. They also had increased expression of APEX1,which is involved in the base excision repair pathway following cisplatin-induced DNA damage. Conclusion: These findings underscore the significance of the tumor microenvironment in modulating tumor cell survival and chemosensitivity. View Publication

SummaryMutations in the DMD gene lead to Duchenne muscular dystrophy (DMD),a severe neuromuscular disorder affecting young boys as they acquire motor functions. DMD is typically diagnosed at 2–4 years of age,but the absence of dystrophin has negative impacts on skeletal muscles before overt symptoms appear in patients,which poses a serious challenge in current standards of care. Here,we investigated the consequences of dystrophin deficiency during skeletal muscle development. We used single-cell transcriptome profiling to characterize the myogenic trajectory of human pluripotent stem cells and showed that DMD cells bifurcate to an alternative branch when they reach the somite stage. Dystrophin deficiency was linked to marked dysregulations of cell junction proteins involved in the cell state transitions characteristic of embryonic somitogenesis. Altogether,this work demonstrates that in vitro,dystrophin deficiency has deleterious effects on cell-cell communication during myogenic development,which should be considered in future therapeutic strategies for DMD. Graphical abstract Highlights•Myogenic differentiation of DMD hiPSCs diverges at the somite stage•Cell junction formation is dysregulated in DMD somite cells•Somite cells from DMD hiPSCs have impaired epithelialization properties•Migration velocity of DMD-mutant somite progenitors is upregulated Natural sciences; Biological sciences; Biochemistry; Cell biology; Stem cells research; Developmental biology. View Publication

Repressor element-1 silencing transcription factor (REST) is a transcriptional repressor involved in neurodevelopment and neuroprotection. REST forms a complex with the REST corepressors,CoREST1,CoREST2,or CoREST3 (encoded by RCOR1,RCOR2,and RCOR3,respectively). Emerging evidence suggests that the CoREST family can target unique genes independently of REST,in various neural and glial cell types during different developmental stages. However,there is limited knowledge regarding the expression and function of the CoREST family in human neurodevelopment. To address this gap,we employed 2D and 3D human pluripotent stem cell (hPSC) models to investigate REST and RCOR gene expression levels. Our study revealed a significant increase in RCOR3 expression in glutamatergic cortical and GABAergic ventral forebrain neurons,as well as mature functional NGN2-induced neurons. Additionally,a simplified astrocyte transdifferentiation protocol resulted in a significant decrease in RCOR2 expression following differentiation. REST expression was notably reduced in mature neurons and cerebral organoids. In summary,our findings provide the first insights into the cell-type-specific expression patterns of RCOR genes in human neuronal and glial differentiation. Specifically,RCOR3 expression increases in neurons,while RCOR2 levels decrease in astrocytes. The dynamic expression patterns of REST and RCOR genes during hPSC neuronal and glial differentiation underscore the potential distinct roles played by REST and CoREST proteins in regulating the development of these cell types in humans. Graphical abstractImage 1 Highlights•REST and RCOR genes display cell-type specific expression patterns in neural cells.•RCOR3 (encodes CoREST3) is upregulated during neuronal and astrocyte differentiation.•RCOR2 (encodes CoREST2) is downregulated during differentiation of astrocytes.•Evidence of potential cell-type specific functions of the CoREST family. View Publication

MYBPC3,encoding cardiac myosin binding protein-C (cMyBP-C),is the most mutated gene known to cause hypertrophic cardiomyopathy (HCM). However,since little is known about the underlying etiology,additional in vitro studies are crucial to defining the underlying molecular mechanisms. Accordingly,this study aimed to investigate the molecular mechanisms underlying the pathogenesis of HCM associated with a polymorphic variant (D389V) in MYBPC3 by using isogenic human-induced pluripotent stem cell (hiPSC)-derived cardiac organoids (hCOs). The hiPSC-derived cardiomyocytes (hiPSC-CMs) and hCOs were generated from human subjects to define the molecular,cellular,functional,and energetic changes caused by the MYBPC3D389V variant,which is associated with increased fractional shortening and highly prevalent in South Asian descendants. Recombinant C0-C2,N’ region of cMyBP-C (wild-type and D389V),and myosin S2 proteins were also utilized to perform binding and motility assays in vitro. Confocal and electron microscopic analyses of hCOs generated from noncarriers (NC) and carriers of the MYBPC3D389V variant revealed the presence of highly organized sarcomeres. Furthermore,functional experiments showed hypercontractility,faster calcium cycling,and faster contractile kinetics in hCOs expressing MYBPC3D389V than NC hCOs. Interestingly,significantly increased cMyBP-C phosphorylation in MYBPC3D389V hCOs was observed,but without changes in total protein levels,in addition to higher oxidative stress and lower mitochondrial membrane potential (??m). Next,spatial mapping revealed the presence of endothelial cells,fibroblasts,macrophages,immune cells,and cardiomyocytes in the hCOs. The hypercontractile function was significantly improved after the treatment of the myosin inhibitor mavacamten (CAMZYOS®) in MYBPC3D389V hCOs. Lastly,various vitro binding assays revealed a significant loss of affinity in the presence of MYBPC3D389V with myosin S2 region as a likely mechanism for hypercontraction. Conceptually,we showed the feasibility of assessing the functional and molecular mechanisms of HCM using highly translatable hCOs through pragmatic experiments that led to determining the MYBPC3D389V hypercontractile phenotype,which was rescued by the administration of a myosin inhibitor. View Publication

The transcription factor Growth Factor Independence 1B (GFI1B) recruits Lysine Specific Demethylase 1 A (LSD1/KDM1A) to stimulate gene programs relevant for megakaryocyte and platelet biology. Inherited pathogenic GFI1B variants result in thrombocytopenia and bleeding propensities with varying intensity. Whether these affect similar gene programs is unknow. Here we studied transcriptomic effects of four patient-derived GFI1B variants (GFI1BT174N,H181Y,R184P,Q287*) in MEG01 megakaryoblasts. Compared to normal GFI1B,each variant affected different gene programs with GFI1BQ287* uniquely failing to repress myeloid traits. In line with this,single cell RNA-sequencing of induced pluripotent stem cell (iPSC)-derived megakaryocytes revealed a 4.5-fold decrease in the megakaryocyte/myeloid cell ratio in GFI1BQ287* versus normal conditions. Inhibiting the GFI1B-LSD1 interaction with small molecule GSK-LSD1 resulted in activation of myeloid genes in normal iPSC-derived megakaryocytes similar to what was observed for GFI1BQ287* iPSC-derived megakaryocytes. Thus,GFI1B and LSD1 facilitate gene programs relevant for megakaryopoiesis while simultaneously repressing programs that induce myeloid differentiation. Using patient-derived induced pluripotent stem cells,the authors show that the transcription factor GFI1B and the lysine demethylase KDM1A/LSD1 promote gene programs while repressing those involved in myeloid differentiation. View Publication

In 2022-23,the world witnessed the largest recorded outbreak of monkeypox virus (MPXV). Neurological manifestations were reported alongside the detection of MPXV DNA and MPXV-specific antibodies in the cerebrospinal fluid of patients. Here,we analyze the susceptibility of neural tissue to MPXV using human neural organoids (hNOs) exposed to a clade IIb isolate. We report susceptibility of several cell types to the virus,including neural progenitor cells and neurons. The virus efficiently replicates in hNOs,as indicated by the exponential increase of infectious viral titers and establishment of viral factories. Our findings reveal focal enrichment of viral antigen alongside accumulation of cell-associated infectious virus,suggesting viral cell-to-cell spread. Using an mNeonGreen-expressing recombinant MPXV,we confirm cell-associated virus transmission. We furthermore show the formation of beads in infected neurites,a phenomenon associated with neurodegenerative disorders. Bead appearance precedes neurite-initiated cell death,as confirmed through live-cell imaging. Accordingly,hNO-transcriptome analysis reveals alterations in cellular homeostasis and upregulation of neurodegeneration-associated transcripts,despite scarcity of inflammatory and antiviral responses. Notably,tecovirimat treatment of MPXV-infected hNOs significantly reduces infectious virus loads. Our findings suggest that viral disruption of neuritic transport drives neuronal degeneration,potentially contributing to MPXV neuropathology and revealing targets for therapeutic intervention. The mechanisms underlying neurological complications of monkeypox virus infection remain unclear. Here,the authors investigate its neurotropic potential and show that neuritic transport of viral particles drives neuronal degeneration. View Publication