The selective autophagy receptors Optineurin and p62 are both required for zebrafish host resistance to mycobacterial infection

PLoS Pathog. 2019 Feb 28;15(2):e1007329. doi: 10.1371/journal.ppat.1007329. eCollection 2019 Feb.

Abstract

Mycobacterial pathogens are the causative agents of chronic infectious diseases like tuberculosis and leprosy. Autophagy has recently emerged as an innate mechanism for defense against these intracellular pathogens. In vitro studies have shown that mycobacteria escaping from phagosomes into the cytosol are ubiquitinated and targeted by selective autophagy receptors. However, there is currently no in vivo evidence for the role of selective autophagy receptors in defense against mycobacteria, and the importance of autophagy in control of mycobacterial diseases remains controversial. Here we have used Mycobacterium marinum (Mm), which causes a tuberculosis-like disease in zebrafish, to investigate the function of two selective autophagy receptors, Optineurin (Optn) and SQSTM1 (p62), in host defense against a mycobacterial pathogen. To visualize the autophagy response to Mm in vivo, optn and p62 zebrafish mutant lines were generated in the background of a GFP-Lc3 autophagy reporter line. We found that loss-of-function mutation of optn or p62 reduces autophagic targeting of Mm, and increases susceptibility of the zebrafish host to Mm infection. Transient knockdown studies confirmed the requirement of both selective autophagy receptors for host resistance against Mm infection. For gain-of-function analysis, we overexpressed optn or p62 by mRNA injection and found this to increase the levels of GFP-Lc3 puncta in association with Mm and to reduce the Mm infection burden. Taken together, our results demonstrate that both Optn and p62 are required for autophagic host defense against mycobacterial infection and support that protection against tuberculosis disease may be achieved by therapeutic strategies that enhance selective autophagy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Autophagy / physiology
  • Cell Cycle Proteins
  • Disease Models, Animal
  • Host-Pathogen Interactions / physiology*
  • Humans
  • Macrophages
  • Membrane Transport Proteins
  • Mycobacterium / pathogenicity
  • Mycobacterium Infections / metabolism
  • Mycobacterium Infections, Nontuberculous / metabolism*
  • Mycobacterium marinum / pathogenicity*
  • Phagosomes
  • Sequestosome-1 Protein
  • Transcription Factor TFIIIA / metabolism
  • Tuberculosis
  • Ubiquitin
  • Zebrafish / metabolism
  • Zebrafish Proteins / metabolism

Substances

  • Cell Cycle Proteins
  • Membrane Transport Proteins
  • OPTN protein, human
  • SQSTM1 protein, human
  • Sequestosome-1 Protein
  • Transcription Factor TFIIIA
  • Ubiquitin
  • Zebrafish Proteins

Supplementary concepts

  • Infection with Mycobacterium marinum

Grants and funding

RZ was supported by a grant from the China Scholarship Council (CSC, https://chinascholarshipcouncil.com/). MV and GFC were funded by the European Marie Skłodowska-Curie program (H2020-MSCA-IF-2014-655424 and H2020-COFUND-2015-FP-707404, respectively; http://ec.europa.eu/research/mariecurieactions/), and AHM and MvdV were supported by the Netherlands Organisation for Scientific Research (NWO) Domain Applied and Engineering Sciences (TTW project 13259, https://www.nwo.nl/en/about-nwo/organisation/nwo-domains/ttw). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.