Deciphering the mitophagy receptor network identifies a crucial role for OPTN (optineurin) in acute myeloid leukemia

Autophagy. 2023 Nov;19(11):2982-2996. doi: 10.1080/15548627.2023.2230839. Epub 2023 Jul 13.

Abstract

The selective autophagic degradation of mitochondria via mitophagy is essential for preserving mitochondrial homeostasis and, thereby, disease maintenance and progression in acute myeloid leukemia (AML). Mitophagy is orchestrated by a variety of mitophagy receptors whose interplay is not well understood. Here, we established a pairwise multiplexed CRISPR screen targeting mitophagy receptors to elucidate redundancies and gain a deeper understanding of the functional interactome governing mitophagy in AML. We identified OPTN (optineurin) as sole non-redundant mitophagy receptor and characterized its unique role in AML. Knockdown and overexpression experiments demonstrated that OPTN expression is rate-limiting for AML cell proliferation. In a MN1-driven murine transplantation model, loss of OPTN prolonged overall median survival by 7 days (+21%). Mechanistically, we found broadly impaired mitochondrial respiration and function with increased mitochondrial ROS, that most likely caused the proliferation defect. Our results decipher the intertwined network of mitophagy receptors in AML for both ubiquitin-dependent and receptor-mediated mitophagy, identify OPTN as a non-redundant tool to study mitophagy in the context of leukemia and suggest OPTN inhibition as an attractive therapeutic strategy.Abbreviations: AML: acute myeloid leukemia; CRISPR: Clustered Regularly Interspaced Short Palindromic Repeats; CTRL: control; DFP: deferiprone; GI: genetic interaction; KD: knockdown; KO: knockout; ldMBM, lineage-depleted murine bone marrow; LFC: log2 fold change; LIR: LC3-interacting region; LSC: leukemic stem cell; MAGeCK: Model-based Analysis of Genome-wide CRISPR-Cas9 Knockout; MDIVI-1: mitochondrial division inhibitor 1; MOI: multiplicity of infection; MOM: mitochondrial outer membrane; NAC: N-acetyl-L-cysteine; OA: oligomycin-antimycin A; OCR: oxygen consumption rate; OE: overexpression; OPTN: optineurin; PINK1: PTEN induced putative kinase 1; ROS: reactive oxygen species; SEM: standard error of the mean; TCGA: The Cancer Genome Atlas; TEM: transmission electron microscopy; UBD: ubiquitin-binding domain; WT: wild type.

Keywords: AML; MN1-driven mouse model; Mitochondrial ROS; Multiplex CRISPR screen; genetic interactions; leukemia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy
  • Humans
  • Leukemia, Myeloid, Acute*
  • Mice
  • Mitophagy* / genetics
  • Reactive Oxygen Species / metabolism
  • Ubiquitin-Protein Ligases / metabolism
  • Ubiquitins

Substances

  • 3-(2,4-dichloro-5-methoxyphenyl)-2-sulfanyl-4(3H)-quinazolinone
  • Reactive Oxygen Species
  • Ubiquitin-Protein Ligases
  • Ubiquitins
  • OPTN protein, human
  • Optn protein, mouse

Grants and funding

This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) SFB1177 [259130777], by the Mildred-Scheel Early Career Center (MSNZ), by the Else Kröner-Forschungskolleg, by the German Cancer Consortium (DKTK) and by the LOEWE Center Frankfurt Cancer Institute (FCI) funded by the Hessen State Ministry for Higher Education, Research and the Arts (III L 5-519/03/03.001-[0015]).