In the future, could patients use an investigational probiotic based on single-cell ribonucleic acid to test their gut health? Researchers at the Helmholtz Institute for RNA-Based Infection Research (HIRI) and Julius-Maximilians-Universität Würzburg (JMU) have developed a new technology they call TIGER. This allows deciphering complex processes in individual cells by documenting early RNA transcripts. The study was published on January 5, 2023 in the journal Nature Biotechnology .
Bacterial and viral infections can cause severe acute symptoms, but can also cause serious long-term consequences, such as the development of cancer. Therefore, scientists are looking for new methods and technologies to better understand the course of diseases and to predict the development of cells and tissues. They use more accurate methods to analyze the main processes in individual cells. One of the goals is to identify changes in the activity of genes, which in turn can indicate a pathological phenomenon.
Ribonucleic acids (RNA) make an important contribution to this understanding. They can provide evidence of gene activity because only active genes make copies of RNA (transcripts) in a process called transcription. However, the transcribed RNA molecules represent only one current state. Combination of previous cellular events, e.g. Bacterial infection, current conditions and future consequences, is difficult.
"The identity and behavior of a cell depends not only on the current intracellular composition and extracellular environment, but also on past conditions. We were looking for an efficient system at the single-cell level to see and connect to the past. At the RNA-based Infection Research (HIRI) in Würzburg Professor Chase Beisel, head of the synthetic RNA biology department at the Helmholtz Institute and lead author of the study, explains.
In their publication, the authors present a new technological approach that could significantly advance medical diagnosis in the future. Their method, called TIGER, is a way to record the presence of specific RNAs in individual living cells.
"Through RNA capture, TIGER connects current cell states with past transcriptional states," said first author Chunlei Jiao. TIGER can measure relative gene expression, detect differences between single nucleotides, record multiple transcripts simultaneously, and read out single cellular events.
According to Jiao, the method has surprising advantages. "Previous studies have used large amounts of data and computational prediction tools to measure asynchronous cells over time to estimate past cell states." The scientists involved in the study were able to document the transfer of antibiotic resistance between Escherichia coli cells as well as the invasion of Salmonella into host cells.
In the future, TIGER can be used to investigate the transcriptional history of individual cells in a living organism and to detect complex cellular responses in vivo and non-invasively by matching the current state. For example, one can imagine taking TIGER probiotics to further document and analyze the state of the digestive system, the authors conclude.
TIGER (short for RNA transcripts derived from genetically encoded entries) uses reprogrammed tracrRNAs (Rptrs) to register selected cellular transcripts as DNA modifiers in every living bacterial cell. Rptrs are designed to associate with known transcripts and convert them into guide RNAs.
The guide RNAs instruct the Cas9 base editor to target the inserted DNA target. The main publication framework can be read in sequence. The technology builds on the research that led to Leopard's in vitro diagnostic platform.
More information: Chunlei Jiao et al., Uptake of RNA into single bacterial cells by modified tracrRNA, Nature Biotechnology (2023). DOI: 10.1038/s41587-022-01604-8
Tiger Deciphering disease progression and cellular processes, in vivo and non-invasively (10 January 2023) Retrieved 12 January 2023 from https://phys.org/news/2023-01-deciphering-disease-cell-tiger - live.html .
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