Project description:Biological systems are inherently complex and heterogeneous. Deciphering this complexity increasingly relies on high-throughput analytical methods and tools that efficiently probe the cellular phenotype and genotype. While recent advancements have enabled various single-cell -omics assays, their broader applications are inherently limited by the challenge of efficiently conducting multi-step biochemical assays while retaining various biological analytes. Extending on our previous work, here we present a versatile technology based on semi-permeable capsules (SPCs), tailored for a variety of high-throughput nucleic acid assays, including digital PCR, genome sequencing, single-cell RNA-sequencing (scRNA-Seq) and FACS-based sorting of individual transcriptomes based on nucleic acid marker of interest. Being biocompatible, the SPCs support single-cell cultivation and clonal expansion over long periods of time – a fundamental limitation of droplet microfluidics systems. Using SPCs we perform scRNA-Seq on white blood cells from patients with hematopoietic disorders and demonstrate that capsule-based sequencing approach (CapSeq) offers superior transcript capture, even for the most challenging cell types. By applying CapSeq on acute myeloid leukemia (AML) samples, we uncover notable changes in transcriptomes of mature granulocytes and monocytes associated with blast and progenitor cell phenotypes. Accurate representation of the entirety of the cellular heterogeneity of clinical samples, driving new insights into the malfunctioning of the innate immune system, and ability to clonally expand individual cells over long period of time, positions SPC technology as customizable, highly sensitive and broadly applicable tool for easy-to-use, scalable single-cell -omics applications.
Project description:Single-cell sequencing may serve as a powerful complementary technique to shotgun metagenomics to study microbiomes. This emerging technology allows the separation of complex microbial communities into individual bacterial cells, enabling high-throughput sequencing of genetic material from thousands of singular bacterial cells in parallel. Here, we validated the use of microfluidics and semi-permeable capsules (SPCs) technology (Atrandi) to isolate individual bacterial cells from sewage and pig fecal samples. Our method involves extracting and amplifying single bacterial DNA within individual SPCs, followed by combinatorial split-and-pool single-amplified genome (SAG) barcoding and short-read sequencing. We tested two different sequencing approaches with different numbers of SPCs from the same sample for each sequencing run. Using a deep sequencing approach, we detected 1,796 and 1,220 SAGs, of which 576 and 599 were used for further analysis from one sewage and one fecal sample, respectively. In shallow sequencing data, we aimed for 10-times more cells and detected 12,731 and 17,909 SAGs, of which we used 2,456 and 1,599 for further analysis for sewage and fecal samples, respectively. Additionally, we identified the top 10 antimicrobial resistance genes (ARGs) in both sewage and feces samples and linked them to their individual host bacterial species.
Project description:Exploiting the full potential of insertional mutagenesis screens with retroviruses and transposons requires methods for distinguishing clonal from subclonal insertion events within heterogeneous tumor cell populations. Current protocols, based on ligation mediated PCR, depend on endonuclease based fragmentation of genomic DNA, resulting in strong biases in amplification and sequencing due to a fixed product sizes of the amplicon. We have developed a method called shear-splink, which enables the semi-quantitative high-throughput sequence analysis of insertional mutations, enabling us to count the number of cells harboring a given integration, within a heterogeneous sample. The shear-splink method enriches for (sub)clonal integrations, thereby reducing the contribution of irrelevant passenger mutations normally hampering a reliable identification of common integration sites. Additionally, this improvement allows us to identify genetic interactions between affected genes, co-occurring mutations and to study acquired resistance mechanisms both in vivo and in vitro.
Project description:The recent advance of single cell sequencing (scRNA-seq) technology such as Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq) allows researchers to quantify cell surface protein abundance and RNA expression simultaneously at single cell resolution. Although CITE-seq and other similar technologies have quickly gained enormous popularity, novel methods for analyzing this new type of single cell multi-omics data are still in urgent need. A limited number of available tools utilize data-driven approach, which may undermine the biological importance of surface protein data. In this study, we developed SECANT, a biology-guided SEmi-supervised method for Clustering, classification, and ANnoTation of single-cell multi-omics. SECANT can be used to analyze CITE-seq data, or jointly analyze CITE-seq and scRNA-seq data. The novelties of SECANT include 1) using confident cell type labels identified from surface protein data as guidance for cell clustering, 2) providing general annotation of confident cell types for each cell cluster, 3) fully utilizing cells with uncertain or missing cell type labels to increase performance, and 4) accurate prediction of confident cell types identified from surface protein data for scRNA-seq data. Besides, as a model-based approach, SECANT can quantify the uncertainty of the results, and our framework can be easily extended to handle other types of multi-omics data. We successfully demonstrated the validity and advantages of SECANT via simulation studies and analysis of public and in-house real datasets. We believe this new method will greatly help researchers characterize novel cell types and make new biological discoveries using single cell multi-omics data.
Project description:Cisplatin-based chemotherapy is the most common treatment for unresectable bladder cancers and also increasingly used as neoadjuvant treatments before or after surgery and radiotherapy. Unfortunately, though many patients respond to the treatment, most of them develop resistance quickly with unclear mechanisms and few further treatment options. Here, we report that semi-squamazation is acquired during chemo treatment in both mice and human. Multi-omics analyses show that cathepsin H (CTSH), a direct target of p63, is associated with chemoresistance and semi-squamation. Treatment with the cathepsin inhibitor E64 specifically restrains chemoresistant but not chemosensitive cancer. Mechanistically, cathepsin inhibition induces fully squamous differentiation of bladder cancer cells, which requires TNF receptor 1alpha and is associated with pyroptosis. Our study suggests that semi-squamazation would be a diagnosistic marker for chemoresistance and differentiation therapy by targeting CTSH might be a potential treatment for chemoresistant bladder cancer.
Project description:Single-cell genomics encompasses a set of methods whereby hundreds to millions of cells are individually subjected to multiplexed assays including sequencing DNA, chromatin accessibility or modification, RNA, or combinations thereof 1,2. These methods enable unbiased, systematic discovery of cellular phenotypes and their dynamics 1–3. Many functional genomic methods, however, require multiple steps that cannot be easily scaled to high throughput, including assays on living cells. Here we develop capsules with amphiphilic gel envelopes (CAGEs), which selectively retain cells, mRNA, and gDNA, while allowing free diffusion of media, enzymes and reagents. CAGEs enable carrying out high-throughput assays that require multiple steps, including combining genomics with live-cell assays. We establish methods for barcoding CAGE DNA and RNA libraries, and apply them to measure persistence of gene expression programs by capturing the transcriptomes of tens of thousands of expanding clones in CAGEs. The compatibility of CAGEs with diverse enzymatic reactions will facilitate the expansion of the current repertoire of single-cell, high-throughput measurements and extend them to live-cell assays.
Project description:Encapsulating bacteria within constrained microenvironments can promote the manifestation of specialized behaviors. Using double-emulsion droplet-generating microfluidic synthesis, live Bacillus subtilis bacteria were encapsulated in a semi-permeable membrane composed of poly(ethylene glycol)-b-poly(D,L-lactic acid) (mPEG-PDLLA). This polymer membrane was sufficiently permeable to permit exponential bacterial growth, metabolite-induced gene expression, and rapid biofilm growth. The biodegradable microparticles retained structural integrity for several days and could be successfully degraded with time or sustained bacterial activity. Microencapsulated B. subtilis successfully captured and contained sodium selenite added outside the polymersomes, converting the selenite into elemental selenium nanoparticles that were selectively retained inside the polymer membrane. This remediation of selenium using polymersomes has high potential for reducing the toxicity of environmental selenium contamination, as well as allowing selenium to be harvested from areas not amenable to conventional waste or water treatment.
Project description:We have adapted a commercial assay that employs mRNA quantification based on the frequency of PCR amplicons determined by next-generation to a high-throughput semi-conductor sequencing platform (Ion-Torrent Proton). We show parallel amplification of pathway derived transcript sets/genes in 12 reference RNA samples followed by sequence-based quantification covering a dynamic range of five orders of magnitude with low technical variation.