Yang H et al. (JAN 2011)
Proceedings of the National Academy of Sciences of the United States of America 108 1 12--7
Completely phased genome sequencing through chromosome sorting.
The two haploid genome sequences that a person inherits from the two parents represent the most fundamentally useful type of genetic information for the study of heritable diseases and the development of personalized medicine. Because of the difficulty in obtaining long-range phase information,current sequencing methods are unable to provide this information. Here,we introduce and show feasibility of a scalable approach capable of generating genomic sequences completely phased across the entire chromosome.
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(Apr 2024)
Nature Communications 15
Complex activity and short-term plasticity of human cerebral organoids reciprocally connected with axons
An inter-regional cortical tract is one of the most fundamental architectural motifs that integrates neural circuits to orchestrate and generate complex functions of the human brain. To understand the mechanistic significance of inter-regional projections on development of neural circuits,we investigated an in vitro neural tissue model for inter-regional connections,in which two cerebral organoids are connected with a bundle of reciprocally extended axons. The connected organoids produced more complex and intense oscillatory activity than conventional or directly fused cerebral organoids,suggesting the inter-organoid axonal connections enhance and support the complex network activity. In addition,optogenetic stimulation of the inter-organoid axon bundles could entrain the activity of the organoids and induce robust short-term plasticity of the macroscopic circuit. These results demonstrated that the projection axons could serve as a structural hub that boosts functionality of the organoid-circuits. This model could contribute to further investigation on development and functions of macroscopic neuronal circuits in vitro. Connecting cerebral organoids with an axon bundle models inter-regional projections and enhances neural activity. Optogenetic stimulation induces short-term plasticity,offering insights into macroscopic circuit development and functionality.
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Dhami P et al. (JAN 2010)
PloS one 5 8 e12339
Complex exon-intron marking by histone modifications is not determined solely by nucleosome distribution.
It has recently been shown that nucleosome distribution,histone modifications and RNA polymerase II (Pol II) occupancy show preferential association with exons (exon-intron marking")�
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(Feb 2024)
Nature Communications 15
Complex regulatory networks influence pluripotent cell state transitions in human iPSCs
Stem cells exist in vitro in a spectrum of interconvertible pluripotent states. Analyzing hundreds of hiPSCs derived from different individuals,we show the proportions of these pluripotent states vary considerably across lines. We discover 13 gene network modules (GNMs) and 13 regulatory network modules (RNMs),which are highly correlated with each other suggesting that the coordinated co-accessibility of regulatory elements in the RNMs likely underlie the coordinated expression of genes in the GNMs. Epigenetic analyses reveal that regulatory networks underlying self-renewal and pluripotency are more complex than previously realized. Genetic analyses identify thousands of regulatory variants that overlapped predicted transcription factor binding sites and are associated with chromatin accessibility in the hiPSCs. We show that the master regulator of pluripotency,the NANOG-OCT4 Complex,and its associated network are significantly enriched for regulatory variants with large effects,suggesting that they play a role in the varying cellular proportions of pluripotency states between hiPSCs. Our work bins tens of thousands of regulatory elements in hiPSCs into discrete regulatory networks,shows that pluripotency and self-renewal processes have a surprising level of regulatory complexity,and suggests that genetic factors may contribute to cell state transitions in human iPSC lines. Stem cells exist in vitro in a spectrum of interconvertible pluripotent states. Here,authors show that pluripotency and self-renewal processes have a high level of regulatory complexity and suggest that genetic factors contribute to cell state transitions in human iPSC lines.
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E. Tsuru et al. ( 2019)
Immunity,inflammation and disease 7 4 318--325
Complexin 2 regulates secretion of immunoglobulin in antibody-secreting cells.
INTRODUCTION Complexins (CPLXs),initially identified in neuronal presynaptic terminals,are cytoplasmic proteins that interact with the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) complex to regulate the fusion of vesicles to the plasma membrane. Although much is known about CPLX function in neuronal synaptic vesicle exocytosis,their distribution and role in immune cells are still unclear. In this study,we investigated CPLX2 knockout (KO) mice to reveal the role of CPLXs in exocytosis of lymphocytes. METHODS We examined the expression of CPLXs and SNAREs in lymphocytes. To study the effect of CPLXs on the immune system in vivo,we analyzed the immune phenotype of CPLX2 KO mice. Furthermore,antibodies secretion from the peritoneal cavity,spleen,and bone marrow cells of wild-type (WT) and CPLX2 KO mice were determined. RESULTS CPLX2 was detected in B cells but not in T cells,while other CPLXs and SNAREs were expressed at a similar level in both B and T cells. To clarify the function of CPLX2 in B lymphocytes,serum concentrations of immunoglobulin G (IgG),IgA,IgM,and IgE were measured in WT and CPLX2 KO mice using enzyme-linked immunosorbent assay. The level of IgM,which mainly consists of natural antibodies,was higher in KO mice than that in WT mice,while the levels of other antibodies were similar in both types of mice. Additionally,we found that spontaneous secretion of IgM and IgG1 was enhanced from the splenic antibody-secreting cells (ASCs) of CPLX2 KO mice. CONCLUSION Our data suggest that CPLX2 inhibits spontaneous secretion of IgM and IgG1 from splenic ASCs. This study provides new insight into the mechanism of antibody secretion of ASCs.
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Yang S-L et al. (DEC 2012)
Protein & cell 3 12 934--942
Compound screening platform using human induced pluripotent stem cells to identify small molecules that promote chondrogenesis.
Articular cartilage,which is mainly composed of collagen II,enables smooth skeletal movement. Degeneration of collagen II can be caused by various events,such as injury,but degeneration especially increases over the course of normal aging. Unfortunately,the body does not fully repair itself from this type of degeneration,resulting in impaired movement. Microfracture,an articular cartilage repair surgical technique,has been commonly used in the clinic to induce the repair of tissue at damage sites. Mesenchymal stem cells (MSC) have also been used as cell therapy to repair degenerated cartilage. However,the therapeutic outcomes of all these techniques vary in different patients depending on their age,health,lesion size and the extent of damage to the cartilage. The repairing tissues either form fibrocartilage or go into a hypertrophic stage,both of which do not reproduce the equivalent functionality of endogenous hyaline cartilage. One of the reasons for this is inefficient chondrogenesis by endogenous and exogenous MSC. Drugs that promote chondrogenesis could be used to induce self-repair of damaged cartilage as a non-invasive approach alone,or combined with other techniques to greatly assist the therapeutic outcomes. The recent development of human induced pluripotent stem cell (iPSCs),which are able to self-renew and differentiate into multiple cell types,provides a potentially valuable cell resource for drug screening in a more relevant" cell type. Here we report a screening platform using human iPSCs in a multi-well plate format to identify compounds that could promote chondrogenesis."
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Davis MI et al. ( 2011)
Nature biotechnology 29 11 1046--1051
Comprehensive analysis of kinase inhibitor selectivity.
We tested the interaction of 72 kinase inhibitors with 442 kinases covering textgreater80% of the human catalytic protein kinome. Our data show that,as a class,type II inhibitors are more selective than type I inhibitors,but that there are important exceptions to this trend. The data further illustrate that selective inhibitors have been developed against the majority of kinases targeted by the compounds tested. Analysis of the interaction patterns reveals a class of 'group-selective' inhibitors broadly active against a single subfamily of kinases,but selective outside that subfamily. The data set suggests compounds to use as tools to study kinases for which no dedicated inhibitors exist. It also provides a foundation for further exploring kinase inhibitor biology and toxicity,as well as for studying the structural basis of the observed interaction patterns. Our findings will help to realize the direct enabling potential of genomics for drug development and basic research about cellular signaling.
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(May 2024)
Nature Communications 15
Comprehensive assessment of mRNA isoform detection methods for long-read sequencing data
The advancement of Long-Read Sequencing (LRS) techniques has significantly increased the length of sequencing to several kilobases,thereby facilitating the identification of alternative splicing events and isoform expressions. Recently,numerous computational tools for isoform detection using long-read sequencing data have been developed. Nevertheless,there remains a deficiency in comparative studies that systemically evaluate the performance of these tools,which are implemented with different algorithms,under various simulations that encompass potential influencing factors. In this study,we conducted a benchmark analysis of thirteen methods implemented in nine tools capable of identifying isoform structures from long-read RNA-seq data. We evaluated their performances using simulated data,which represented diverse sequencing platforms generated by an in-house simulator,RNA sequins (sequencing spike-ins) data,as well as experimental data. Our findings demonstrate IsoQuant as a highly effective tool for isoform detection with LRS,with Bambu and StringTie2 also exhibiting strong performance. These results offer valuable guidance for future research on alternative splicing analysis and the ongoing improvement of tools for isoform detection using LRS data. Recently,various computational tools have emerged for detecting mRNA isoforms using long-read sequencing data. Here,the authors systemically evaluate and compare the performance of these tools.
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Collier AJ et al. (MAR 2017)
Cell stem cell 20 6 874--890.e7
Comprehensive Cell Surface Protein Profiling Identifies Specific Markers of Human Naive and Primed Pluripotent States.
Human pluripotent stem cells (PSCs) exist in naive and primed states and provide important models to investigate the earliest stages of human development. Naive cells can be obtained through primed-to-naive resetting,but there are no reliable methods to prospectively isolate unmodified naive cells during this process. Here we report comprehensive profiling of cell surface proteins by flow cytometry in naive and primed human PSCs. Several naive-specific,but not primed-specific,proteins were also expressed by pluripotent cells in the human preimplantation embryo. The upregulation of naive-specific cell surface proteins during primed-to-naive resetting enabled the isolation and characterization of live naive cells and intermediate cell populations. This analysis revealed distinct transcriptional and X chromosome inactivation changes associated with the early and late stages of naive cell formation. Thus,identification of state-specific proteins provides a robust set of molecular markers to define the human PSC state and allows new insights into the molecular events leading to naive cell resetting.
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Liu X et al. (NOV 2017)
Nature methods 14 11 1055--1062
Comprehensive characterization of distinct states of human naive pluripotency generated by reprogramming.
Recent reports on the characteristics of naive human pluripotent stem cells (hPSCs) obtained using independent methods differ. Naive hPSCs have been mainly derived by conversion from primed hPSCs or by direct derivation from human embryos rather than by somatic cell reprogramming. To provide an unbiased molecular and functional reference,we derived genetically matched naive hPSCs by direct reprogramming of fibroblasts and by primed-to-naive conversion using different naive conditions (NHSM,RSeT,5iLAF and t2iLGöY). Our results show that hPSCs obtained in these different conditions display a spectrum of naive characteristics. Furthermore,our characterization identifies KLF4 as sufficient for conversion of primed hPSCs into naive t2iLGöY hPSCs,underscoring the role that reprogramming factors can play for the derivation of bona fide naive hPSCs.
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(Feb 2024)
Nature Communications 15
Comprehensive characterization of IFNγ signaling in acute myeloid leukemia reveals prognostic and therapeutic strategies
Interferon gamma (IFNγ) is a critical cytokine known for its diverse roles in immune regulation,inflammation,and tumor surveillance. However,while IFNγ levels were elevated in sera of most newly diagnosed acute myeloid leukemia (AML) patients,its complex interplay in AML remains insufficiently understood. We aim to characterize these complex interactions through comprehensive bulk and single-cell approaches in bone marrow of newly diagnosed AML patients. We identify monocytic AML as having a unique microenvironment characterized by IFNγ producing T and NK cells,high IFNγ signaling,and immunosuppressive features. IFNγ signaling score strongly correlates with venetoclax resistance in primary AML patient cells. Additionally,IFNγ treatment of primary AML patient cells increased venetoclax resistance. Lastly,a parsimonious 47-gene IFNγ score demonstrates robust prognostic value. In summary,our findings suggest that inhibiting IFNγ is a potential treatment strategy to overcoming venetoclax resistance and immune evasion in AML patients. IFNγ signaling is important in the pathogenesis and immune response,emphasizing the need for investigation of its role. Here,the authors show that IFNγ plays a key role in shaping immune microenvironment in AML and developing resistance,providing insights for potential therapeutic strategies.
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L. Yao et al. (oct 2022)
Cancer research communications 2 10 1255--1265
Comprehensive Characterization of the Multiple Myeloma Immune Microenvironment Using Integrated scRNA-seq, CyTOF, and CITE-seq Analysis.
UNLABELLED As part of the Multiple Myeloma Research Foundation (MMRF) immune atlas pilot project,we compared immune cells of multiple myeloma bone marrow samples from 18 patients assessed by single-cell RNA sequencing (scRNA-seq),mass cytometry (CyTOF),and cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) to understand the concordance of measurements among single-cell techniques. Cell type abundances are relatively consistent across the three approaches,while variations are observed in T cells,macrophages,and monocytes. Concordance and correlation analysis of cell type marker gene expression across different modalities highlighted the importance of choosing cell type marker genes best suited to particular modalities. By integrating data from these three assays,we found International Staging System stage 3 patients exhibited decreased CD4+ T/CD8+ T cells ratio. Moreover,we observed upregulation of RAC2 and PSMB9,in natural killer cells of fast progressors compared with those of nonprogressors,as revealed by both scRNA-seq and CITE-seq RNA measurement. This detailed examination of the immune microenvironment in multiple myeloma using multiple single-cell technologies revealed markers associated with multiple myeloma rapid progression which will be further characterized by the full-scale immune atlas project. SIGNIFICANCE scRNA-seq,CyTOF,and CITE-seq are increasingly used for evaluating cellular heterogeneity. Understanding their concordances is of great interest. To date,this study is the most comprehensive examination of the measurement of the immune microenvironment in multiple myeloma using the three techniques. Moreover,we identified markers predicted to be significantly associated with multiple myeloma rapid progression.
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