Project description:We developed a modular, high-throughput discovery platform to simultaneously test whether Mut PIK3Ca is immunogenic and to retrieve paired a/b TCR gene sequences that confer specificity to this NeoAg. This method, termed Stimulation Induced Functional TCR sequencing (SIFT-seq), combines single-cell (sc) TCR V(D)J and transcriptome sequencing. Here, microwell cultures of in vitro stimulated T cells with confirmed neoantigen-specific recognition are selected for SIFT-seq. Matched aliquots of selected wells are acutely stimulated with autologous antigen-presenting cells presenting WT or Mut PI3Ka and the transcriptomic profile of individual clonotypes is assessed to identify neoantigen-specific T cells and retrieve their TCR gene sequences.
Project description:Dendritic cells are key player to initiate anti-tumoral response. In this study we aimed to characterize the function of type 1 DCs during priming of CD8 T cell responses against endogenous neoantigens encoded by a KrasG12D/WT; Tp53 (KP) lung cancer model. To enhance the immunostimulatory properties of cDC1, we delivered a combination of Flt3L and aCD40 antibodies. We found that this therapy is sufficient to induce proliferation of neoantigen specific CD8 T cells and restrain growth of lung tumor nodules. scRNA-seq transcriptional profiling of the lung immune infiltrate of tumor-challenged animals with and without DC-therapy was performed to understand the molecular changes induced in DCs subsets and CD8 T cell subsets.
Project description:Existing protocols for full-length single-cell RNA sequencing (scRNA-seq) produce libraries of high complexity (thousands of distinct genes) with outstanding sensitivity and specificity of transcript quantification. These full-length libraries have the advantage of allowing probing of transcript isoforms, are informative regarding single nucleotide polymorphisms, and allow assembly of the VDJ region of the T- and B-cell receptor sequences. Since full length protocols are mostly plate-based at present, they are also suited to profiling cell types where cell numbers are limiting, such as rare cell types during development for instance. A disadvantage of these methods has been the scalability and cost of the experiments, which has limited their popularity as compared to droplet-based and nanowell approaches. Here, we describe an automated protocol for full-length scRNA-seq, including both an in-house automated SMART-seq2 protocol, and a commercial kit-based workflow. We discuss these two protocols in terms of ease-of-use, equipment requirements, running time, cost per sample and sequencing quality. By benchmarking the lysis buffers, reverse transcription enzymes and their combinations, we propose an optimized in-house automated protocol with dramatically reduced cost. These pipelines have been employed successfully for several research projects allied with the Human Cell Atlas initiative (www.humancellatlas.org) and are available on protocols.io.
Project description:For high-throughput sequencing and quantification of immunoglobulin repertoires, most methodologies utilise RNA. However, output varies enormously between recombined genes due to different promoter strengths and differential activation of lymphocyte subsets, precluding quantitation of recombinants on a per cell basis. To date, DNA-based approaches have used V gene primer cocktails, with substantial inherent biases. Here we describe VDJ-seq, which accurately quantitates immunoglobulin diversity at the DNA level in an unbiased manner. This is accomplished with a single primer extension step using biotinylated J gene primers. By addition of unique molecular identifiers (UMI) before primer extension, we reliably remove duplicate sequences and correct for sequencing and PCR errors. Furthermore, VDJ-seq captures productive and non-productive VDJ and DJ recombination events on a per cell basis. Library preparation takes 3 days, with 2 days of sequencing, and 1 day of data processing and analysis.
Project description:Mutations in RNA splicing factors are prevalent across cancers and generate recurrently mis-spliced mRNA isoforms. Here we identified a series of bona fide neoantigens translated from highly stereotyped splicing alterations promoted by neomorphic, leukemia-associated somatic mutations in the splicing machinery. We utilized feature-barcoded peptide-MHC dextramers to isolate neoantigen-specific T cell receptors (TCR) from both healthy donors and patients with leukemia. While circulating neoantigen-specific CD8+ T cells were identified in patients with active disease, they were dysfunctional with reduced inflammatory response gene signatures. In contrast, donor CD8+ T cells with tumor-reactive TCRs were present following curative allogeneic hematopoietic cell transplant. T cells engineered with TCRs recognizing an SRSF2 mutant-induced neoantigen in CLK3 resulted in specific recognition and cytotoxicity of SRSF2 mutant leukemia. These data identify RNA mis-splicing derived neoantigens and neoantigen-specific TCRs across patients and provide proof-of-concept to genetically redirect T cells to public mis-splicing derived neoantigens in myeloid leukemias.
Project description:Analysis of the antibody repertoire composition is now possible using VDJ-seq. We used this recently developed method for unbiased amplification from genomic DNA (gDNA) to directly compare the Igh repertoire of C57Bl/6 (WT) and NE1-/- pro-B cells. We find that a group of contiguous proximal and intermediate VH genes are under-utilized in V->DJ rearrangement in the absence of NE1 revealing a NE1 zone of influence. We report the VH gene usage profile from WT and NE1-/- primary pro-B cells from the VDJ-seq data.
Project description:Energy metabolism and extracellular matrix function are closely connected to orchestrate and maintain tissue organization, but the crosstalk is poorly understood. Here, we used scRNA-seq analysis to uncover the importance of respiration for extracellular matrix homeostasis in mature cartilage. Genetic inhibition of respiration in cartilage results in the expansion of a central area of 1-month-old mouse femur head cartilage showing disorganized chondrocytes and increased deposition of extracellular matrix material. scRNA-seq analysis identified a cluster-specific decrease in mitochondrial DNA-encoded respiratory chain genes and a unique regulation of extracellular matrix-related genes in nonarticular chondrocyte clusters. These changes were associated with alterations in extracellular matrix composition, a shift in the collagen/non-collagen protein content and an increase of collagen crosslinking and ECM stiffness. The results demonstrate, based on findings of the scRNA-seq analysis, that respiration is a key factor contributing to ECM integrity and mechanostability in cartilage and presumably also in many other tissues.