Project description:All bulk CRISPR based screens CD2 and B2M CRISPRi tiling screens (primary human CD8 T cells), IL2RA CRISPRa tiling screens (Jurkats), CRISPRi/a TF screens (primary human CD8 T cells), and CRISPR TFome KO (primary human T cells)
Project description:We demonstrate that vector designs for such screens that rely on cis linkage of guides and distally located barcodes suffer from swapping of intended guide-barcode associations at rates approaching 50% due to template switching during lentivirus production, greatly reducing sensitivity.
Project description:CRISPR/Cas9-based functional genomics have transformed our ability to elucidate mammalian cell biology. Most previous CRISPR-based screens were implemented in cancer cell lines, rather than healthy, differentiated cells. Here, we describe a CRISPR interference (CRISPRi)-based platform for genetic screens in human neurons derived from induced pluripotent stem cells (iPSCs). We demonstrate robust and durable knockdown of endogenous genes in such neurons, and present results from three complementary genetic screens. A survival-based screen revealed neuron-specific essential genes and a small number of genes that improved neuronal survival upon knockdown. A screen with a single-cell transcriptomic readout uncovered several examples for genes knockdown of which had dramatically different cell-type specific consequences. A longitudinal imaging screen detected distinct consequences of gene knockdown on neuronal morphology. Our results highlight the potential of interrogating cell biology in iPSC-derived differentiated cell types and provide a platform for the systematic dissection of normal and disease states of neurons.
Project description:Uncovering the genetic basis of molecular processes is essential for understanding a broad range of biological phenomena. CRIPSR-Cas9 approaches enable this discovery through programable and systematic profiling of regulatory genes underlying diverse cellular behaviors. A key challenge for dissecting genetic networks is expanding CRISPR-based screens to interrogate specific phenotypes with high precision. Here, we use a quantitative, sequencing-based CRISPRi platform to enhance the scope and sensitivity of genome-wide screens. We first systematically explore how technical variations distort guide effects and correct for these factors by using RNA reporters and normalizers expressed from closely matched promoters. We then combine this platform with a recombinase-based integration system to interrogate protein and RNA-level phenotypes. We find our approach accurately captures known regulators of protein or RNA quality control with high accuracy and minimal background. These barcode-based CRISPR systems provide a powerful and generalizable platform for dissecting critical cellular regulatory pathways.
Project description:Tumor Infiltrating Lymphocyte (TIL) therapy have shown promise in the treatment of patients with refractory solid tumors, with improvement in response rates and durability of responses nevertheless sought. To identify targets capable of enhancing the anti-tumor activity of T cell therapies, large-scale in vitro and in vivo CRISPR/Cas9 screens were performed, with the suppressor of cytokine signaling 1 (SOCS1) gene identified as a top T cell-enhancing target. In murine CD8 T cell therapy models, SOCS1 served as a critical checkpoint in restraining the accumulation of T central memory cells in lymphoid organs as well as intermediate (Texint) and effector (Texeff) exhausted T cell subsets derived from progenitor exhausted T cell (Texprog) cells in tumors. A comprehensive CRISPR tiling screen of the SOCS1 coding region identified sgRNAs targeting the SH2 domain of SOCS1 as the most potent, with a sgRNA with minimal off-target cut sites used to manufacture KSQ-001, an engineered TIL therapy with SOCS1 inactivated by CRISPR/Cas9. KSQ-001 possessed increased responsiveness to cytokine signals and enhanced in vivo anti-tumor function in mouse models. These data demonstrate the use of CRISPR/Cas9 screens in the rational design of T cell therapies.