来自杂志 bioRxiv : the preprint server for biology 的文献。
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1.
徐炳祥 (2024-07-31 13:54):
#paper doi: 10.1101/2024.04.18.590148 bioRxiv, 2024, Droplet Hi-C for Fast and Scalable Profiling of Chromatin Architecture in Single Cells。单细胞Hi-C技术是目前单细胞三维基因组研究的主要技术手段,然而现有单细胞Hi-C技术存在通量不高,实验流程复杂,获取的单细胞文库质量较差等缺点。在本预印本论文中,作者们介绍了一种基于微流控技术的单细胞Hi-C技术的改良,称为Droplet Hi-C。Droplet Hi-C将单细胞Hi-C中barcoding步骤改为使用微流控平台自动化进行,从而大幅加快了文库构建的自动化水平和效率。Droplet Hi-C可实现超过4万个细胞的单细胞Hi-C文库的平行构建。借助此技术,作者分析了小鼠脑神经元中的染色质构象图谱的分布,研究了结直肠癌细胞系和组织中染色体外DNA的分布,实现了高通量的单细胞Hi-C和转录组共同构建。需要指出的是,论文仅提升了文库构建的效率,并未提升单个单细胞文库的质量,这可能是本领域下一个需要突破的重要技术瓶颈。
Abstract:
Comprehensive analysis of chromatin architecture is crucial for understanding the gene regulatory programs during development and in disease pathogenesis, yet current methods often inadequately address the unique challenges presented by … >>>
Comprehensive analysis of chromatin architecture is crucial for understanding the gene regulatory programs during development and in disease pathogenesis, yet current methods often inadequately address the unique challenges presented by analysis of heterogeneous tissue samples. Here, we introduce Droplet Hi-C, which employs a commercial microfluidic device for high-throughput, single-cell chromatin conformation profiling in droplets. Using Droplet Hi-C, we mapped the chromatin architecture at single-cell resolution from the mouse cortex and analyzed gene regulatory programs in major cortical cell types. Additionally, we used this technique to detect copy number variation (CNV), structural variations (SVs) and extrachromosomal DNA (ecDNA) in cancer cells, revealing clonal dynamics and other oncogenic events during treatment. We further refined this technique to allow for joint profiling of chromatin architecture and transcriptome in single cells, facilitating a more comprehensive exploration of the links between chromatin architecture and gene expression in both normal tissues and tumors. Thus, Droplet Hi-C not only addresses critical gaps in chromatin analysis of heterogeneous tissues but also emerges as a versatile tool enhancing our understanding of gene regulation in health and disease. <<<
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2.
翁凯 (2024-04-30 22:44):
#paper doi:10.1101/2024.03.18.585576,bioRxiv,2024-03-19。Single-cell genomics and regulatory networks for 388 human brains。这个研究首次在人群规模对人脑前额叶区域进行了单细胞核转录组、染色质可及性测序,然后在细胞类型的精度对基因调控网络、细胞通讯网络等方面进行了生理和病理条件下的探究。研究结果可以在项目(brainSCOPE)的官网获取。官网:http://brainscope.psychencode.org。该研究用了388个人的脑。其中333个是该研究产生的,55个是外来的;健康个体有182个,其余有精神分裂症、双相障碍(抑郁狂躁型忧郁症)、自闭症或老年痴呆。388个个体有snRNA-seq数据。59个个体有snATAC-seq数据,其中40个的是snMultiome(对同一个细胞既测转录组又测ATAC)。质控后共280万个细胞核(注释到了28种细胞)。【研究角度及部分主要发现】1,对每种细胞找cis-eQTL和cis调控元件。2,构建细胞类型特异性的基因调控网络和细胞间通信网络,并展示这些网络在衰老和神经精神疾病中的变异。3,探究每种细胞的占比、基因表达、表观遗传和年龄、老年痴呆的关联。用基因表达量构建预测年龄的摸型。发现有6种细胞的转录组有很强的预测能力。4,在每种细胞里构建摸型,用遗传变异预测对细胞、组织的基因表达的影响。模拟基因序列的干绕对基因表达、表型(包括疾病倾向)等下游的影响。【研究的不足或未来研究方向】 1,RNA表达量不能代替蛋白表达量。这在某些脑区尤其突出。2,人去世后的脑组织和活人的脑组织有区别。3,研究更多脑区,以及发育、衰老中的脑区或者类器官。4,整合更多类型的数据,比如成像数据,用于提升预测表型的能力。【应用前景】1,为理解神经精神疾病的分子机制提供了新的视角,有助于发现新的治疗方法。2,通过整合模型(LNCTP),可以从基因型数据中预测个体的细胞类型特异性功能基因表达,为精准医疗提供工具。3,研究结果可用于优先考虑潜在的药物靶点,并模拟特定基因的表达变化,以预测其对疾病表型的潜在影响。4,该研究创建的brainSCOPE资源库可供其他研究者使用,以进一步探索大脑的分子结构和功能。总体而言,这项研究通过大规模的单细胞分析,为理解人类大脑的复杂性、疾病机制和潜在的治疗干预提供了宝贵的资源和新的洞见。
Abstract:
Single-cell genomics is a powerful tool for studying heterogeneous tissues such as the brain. Yet, little is understood about how genetic variants influence cell-level gene expression. Addressing this, we uniformly … >>>
Single-cell genomics is a powerful tool for studying heterogeneous tissues such as the brain. Yet, little is understood about how genetic variants influence cell-level gene expression. Addressing this, we uniformly processed single-nuclei, multi-omics datasets into a resource comprising >2.8M nuclei from the prefrontal cortex across 388 individuals. For 28 cell types, we assessed population-level variation in expression and chromatin across gene families and drug targets. We identified >550K cell-type-specific regulatory elements and >1.4M single-cell expression-quantitative-trait loci, which we used to build cell-type regulatory and cell-to-cell communication networks. These networks manifest cellular changes in aging and neuropsychiatric disorders. We further constructed an integrative model accurately imputing single-cell expression and simulating perturbations; the model prioritized ~250 disease-risk genes and drug targets with associated cell types. <<<
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3.
颜林林 (2024-01-30 09:58):
#paper doi:10.1101/2023.12.20.570816. bioRxiv, 2024, Neoantigen Cancer Vaccines and Different Immune Checkpoint Therapies Each Utilize Both Converging and Distinct Mechanisms that in Combination Enable Synergistic Therapeutic Efficacy. 本文使用甲基胆蒽烷(Methylcholanthrene,简称MCA,一种化学致癌物)诱导基因工程小鼠,构造了肉瘤动物模型,并以此作为研究体系,比较了新抗原疫苗和抗CTLA-4/抗PD-1的疗效。两种疗法都能促进肿瘤内特定CD8 T细胞的扩张,而新抗原疫苗的效应更为显著。文章通过单细胞转录组测序和单细胞免疫组库测序,分析了不同疗法导致了免疫微环境变化,揭示了这些细胞克隆型扩张与特定免疫治疗相关的表型和功能状态。新抗原疫苗与ICT联合使用显示出比单独使用任一治疗更高的疗效,为联合使用肿瘤免疫和免疫检查点治疗方法提供了证据支持。
Abstract:
The goal of therapeutic cancer vaccines and immune checkpoint therapy (ICT) is to eliminate cancer by expanding and/or sustaining T cells with anti-tumor capabilities. However, whether cancer vaccines and ICT … >>>
The goal of therapeutic cancer vaccines and immune checkpoint therapy (ICT) is to eliminate cancer by expanding and/or sustaining T cells with anti-tumor capabilities. However, whether cancer vaccines and ICT enhance anti-tumor immunity by distinct or overlapping mechanisms remains unclear. Here, we compared effective therapeutic tumor-specific mutant neoantigen (NeoAg) cancer vaccines with anti-CTLA-4 and/or anti-PD-1 ICT in preclinical models. Both NeoAg vaccines and ICT induce expansion of intratumoral NeoAg-specific CD8 T cells, though the degree of expansion and acquisition of effector activity was much more substantial following NeoAg vaccination. Further, we found that NeoAg vaccines are particularly adept at inducing proliferating and stem-like NeoAg-specific CD8 T cells. Single cell T cell receptor (TCR) sequencing revealed that TCR clonotype expansion and diversity of NeoAg-specific CD8 T cells relates to their phenotype and functional state associated with specific immunotherapies employed. Effective NeoAg vaccines and ICT required both CD8 and CD4 T cells. While NeoAg vaccines and anti-PD-1 affected the CD4 T cell compartment, it was to less of an extent than observed with anti-CTLA-4, which notably induced ICOSBhlhe40 Th1-like CD4 T cells and, when combined with anti-PD-1, a small subset of Th2-like CD4 T cells. Although effective NeoAg vaccines or ICT expanded intratumoral M1-like iNOS macrophages, NeoAg vaccines expanded rather than suppressed (as observed with ICT) M2-like CX3CR1CD206 macrophages, associated with the vaccine adjuvant. Further, combining NeoAg vaccination with ICT induced superior efficacy compared to either therapy in isolation, highlighting the utility of combining these modalities to eliminate cancer. <<<
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4.
颜林林 (2023-12-27 12:42):
#paper doi:10.1101/2023.10.04.560604. bioRxiv, 2023, Federated Learning for multi-omics: a performance evaluation in Parkinson's disease. 这篇文章基于两个帕金森病研究的数据集(PPMI和PDBP),这两个数据集都入组了数百例患者和对照健康人,分别都进行了WGS和RNA-seq,获得了多组学检测的分析特征结果。通过将PPMI拆分为K折,留出一折后所剩余K-1折用于模型训练,再将模型放到PPMI预先留出的一折数据和PBMP上进行测试和性能评估。建模分别使用了集中化的机器学习方法,以及将数据拆分到多个节点(site)以采取联邦学习法,并使用了不同的联邦学习策略。结果显示,虽然样本在不同site的分散程度、联邦学习的策略等都会对最终性能有所影响,但联邦学习的最优结果,能与集中化训练的性能相当。此外,本文对联邦学习的训练时间进行评估,比集中化的方法至少高出一个数量级。虽然如此,由于联邦学习可以避免大规模数据在不同sites之间分享和传输,对于整合更广泛的数据,提升模型性能,还是有优势的。提供了对联邦学习在多组学和特别是在帕金森病预测中的应用的深入分析,展示了其作为一种协作工具在处理大规模异构数据时的潜力和挑战。
Abstract:
While machine learning (ML) research has recently grown more in popularity, its application in the omics domain is constrained by access to sufficiently large, high-quality datasets needed to train ML … >>>
While machine learning (ML) research has recently grown more in popularity, its application in the omics domain is constrained by access to sufficiently large, high-quality datasets needed to train ML models. Federated Learning (FL) represents an opportunity to enable collaborative curation of such datasets among participating institutions. We compare the simulated performance of several models trained using FL against classically trained ML models on the task of multi-omics Parkinson's Disease prediction. We find that FL model performance tracks centrally trained ML models, where the most performant FL model achieves an AUC-PR of 0.876 ± 0.009, 0.014 ± 0.003 less than its centrally trained variation. We also determine that the dispersion of samples within a federation plays a meaningful role in model performance. Our study implements several open source FL frameworks and aims to highlight some of the challenges and opportunities when applying these collaborative methods in multi-omics studies. <<<
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