Excessive R-loops trigger an inflammatory cascade leading to increased HSPC production

Joshua T. Weinreb, Noura Ghazale, Kith Pradhan, Varun Gupta, Kathryn S. Potts, Brad Tricomi, Noah J. Daniels, Richard A. Padgett, Sofia De Oliveira, Amit Verma, Teresa V. Bowman

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Hematopoietic stem and progenitor cells (HSPCs) arise during embryonic development and are essential for sustaining the blood and immune systems throughout life. Tight regulation of HSPC numbers is critical for hematopoietic homeostasis. Here, we identified DEAD-box helicase 41 (Ddx41) as a gatekeeper of HSPC production. Using zebrafish ddx41 mutants, we unveiled a critical role for this helicase in regulating HSPC production at the endothelial-to-hematopoietic transition. We determined that Ddx41 suppresses the accumulation of R-loops, nucleic acid structures consisting of RNA:DNA hybrids and ssDNAs whose equilibrium is essential for cellular fitness. Excess R-loop levels in ddx41 mutants triggered the cGAS-STING inflammatory pathway leading to increased numbers of hemogenic endothelium and HSPCs. Elevated R-loop accumulation and inflammatory signaling were observed in human cells with decreased DDX41, suggesting possible conservation of mechanism. These findings delineate that precise regulation of R-loop levels during development is critical for limiting cGAS-STING activity and HSPC numbers. Weinreb et al. show a link between R-loops, inflammation, and the developing hematopoietic system. Ddx41 acts as a gatekeeper of HSPC production by suppressing R-loop accumulation and the cGAS-STING inflammatory pathway. Elevated R-loops and inflammatory signaling were also observed in human cells with decreased DDX41, suggesting possible conservation of mechanism.

Original languageEnglish (US)
Pages (from-to)627-640.e5
JournalDevelopmental cell
Volume56
Issue number5
DOIs
StatePublished - Mar 8 2021

Keywords

  • Ddx41
  • R-loops
  • hematopoietic stem and progenitor cell
  • inflammatory signaling
  • zebrafish

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Developmental Biology
  • Cell Biology

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