Mitochondrial RNA, a new trigger of the innate immune system

Wiley Interdiscip Rev RNA. 2022 May;13(3):e1690. doi: 10.1002/wrna.1690. Epub 2021 Sep 8.

Abstract

Mitochondria play a pivotal role in numerous cellular processes. One of them is regulation of the innate immune pathway. In this instance, mitochondria function in two different aspects of regulatory mechanisms. First, mitochondria are part of the antiviral signaling cascade that is triggered in the cytoplasm and transmitted to effector proteins through mitochondria-localized proteins. Second, mitochondria can become an endogenous source of innate immune stimuli. Under some pathophysiological conditions, mitochondria release to the cytoplasm immunogenic factors, such as mitochondrial nucleic acids. Here, we focus on immunogenic mitochondrial double-stranded RNA (mt-dsRNA) and its origin and metabolism. We discuss factors that are responsible for regulating mt-dsRNA and its escape from mitochondria, emphasizing the contribution of polynucleotide phosphorylase (PNPase, PNPT1). Finally, we review current knowledge of the role of PNPase in human health and disease. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Keywords: innate immunity; mitochondrial RNA decay and surveillance; mitochondrial dsRNA.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Exoribonucleases / metabolism
  • Humans
  • Immune System / metabolism
  • Immunity, Innate
  • Mitochondria / metabolism
  • Polyribonucleotide Nucleotidyltransferase* / genetics
  • Polyribonucleotide Nucleotidyltransferase* / metabolism
  • RNA, Double-Stranded* / metabolism
  • RNA, Mitochondrial / metabolism

Substances

  • RNA, Double-Stranded
  • RNA, Mitochondrial
  • Polyribonucleotide Nucleotidyltransferase
  • Exoribonucleases
  • PNPT1 protein, human