Dataset Information

CRISPR RNAs trigger innate immune responses in human cells.

ABSTRACT: Here, we report that CRISPR guide RNAs (gRNAs) with a 5'-triphosphate group (5'-ppp gRNAs) produced via in vitro transcription trigger RNA-sensing innate immune responses in human and murine cells, leading to cytotoxicity. 5'-ppp gRNAs in the cytosol are recognized by DDX58, which in turn activates type I interferon responses, causing up to ?80% cell death. We show that the triphosphate group can be removed by a phosphatase in vitro and that the resulting 5'-hydroxyl gRNAs in complex with Cas9 or Cpf1 avoid innate immune responses and can achieve targeted mutagenesis at a frequency of 95% in primary human CD4+ T cells. These results are in line with previous findings that chemically synthesized sgRNAs with a 5'-hydroxyl group are much more efficient than in vitro-transcribed (IVT) sgRNAs in human and other mammalian cells. The phosphatase treatment of IVT sgRNAs is a cost-effective method for making highly active sgRNAs, avoiding innate immune responses in human cells.

SUBMITTER: Kim S

PROVIDER: S-EPMC5848615 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

CRISPR RNAs trigger innate immune responses in human cells.

Kim Sojung S Koo Taeyoung T Jee Hyeon-Gun HG Cho Hee-Yeon HY Lee Gyeorae G Lim Dong-Gyun DG Shin Hyoung Shik HS Kim Jin-Soo JS

Genome research 20180301 3

Here, we report that CRISPR guide RNAs (gRNAs) with a 5'-triphosphate group (5'-ppp gRNAs) produced via in vitro transcription trigger RNA-sensing innate immune responses in human and murine cells, leading to cytotoxicity. 5'-ppp gRNAs in the cytosol are recognized by DDX58, which in turn activates type I interferon responses, causing up to ∼80% cell death. We show that the triphosphate group can be removed by a phosphatase in vitro and that the resulting 5'-hydroxyl gRNAs in complex with Cas9 o ...[more]

PMID: 29472270

Similar Datasets

Project description:Invading pathogen nucleic acids are recognized and bound by cytoplasmic (retinoic acid-inducible gene I [RIG-I]-like) and membrane-bound (Toll-like) pattern recognition receptors to activate innate immune signaling. Modified nucleotides, when present in RNA molecules, diminish the magnitude of these signaling responses. However, mechanisms explaining the blunted signaling have not been elucidated. In this study, we used several independent biological assays, including inhibition of virus replication, RIG-I:RNA binding assays, and limited trypsin digestion of RIG-I:RNA complexes, to begin to understand how RNAs containing modified nucleotides avoid or suppress innate immune signaling. The experiments were based on a model innate immune activating RNA molecule, the polyU/UC RNA domain of hepatitis C virus, which was transcribed in vitro with canonical nucleotides or with one of eight modified nucleotides. The approach revealed signature assay responses associated with individual modified nucleotides or classes of modified nucleotides. For example, while both N-6-methyladenosine (m6A) and pseudouridine nucleotides correlate with diminished signaling, RNA containing m6A modifications bound RIG-I poorly, while RNA containing pseudouridine bound RIG-I with high affinity but failed to trigger the canonical RIG-I conformational changes associated with robust signaling. These data advance understanding of RNA-mediated innate immune signaling, with additional relevance for applying nucleotide modifications to RNA therapeutics. The innate immune system provides the first response to virus infections and must distinguish between host and pathogen nucleic acids to mount a protective immune response without activating autoimmune responses. While the presence of nucleotide modifications in RNA is known to correlate with diminished innate immune signaling, the underlying mechanisms have not been explored. The data reported here are important for defining mechanistic details to explain signaling suppression by RNAs containing modified nucleotides. The results suggest that RNAs containing modified nucleotides interrupt signaling at early steps of the RIG-I-like innate immune activation pathway and also that nucleotide modifications with similar chemical structures can be organized into classes that suppress or evade innate immune signaling steps. These data contribute to defining the molecular basis for innate immune signaling suppression by RNAs containing modified nucleotides. The results have important implications for designing therapeutic RNAs that evade innate immune detection.

Dataset Information

CRISPR RNAs trigger innate immune responses in human cells.

Publications

CRISPR RNAs trigger innate immune responses in human cells.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets