Scientific article
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English

Toll-like receptor 4 and macrophage scavenger receptor 1 crosstalk regulates phagocytosis of a fungal pathogen

Published inNature communications, vol. 14, no. 1, 4895
Publication date2023-08-14
First online date2023-08-14
Abstract

The opportunistic fungal pathogen Cryptococcus neoformans causes lethal infections in immunocompromised patients. Macrophages are central to the host response to cryptococci; however, it is unclear how C. neoformans is recognised and phagocytosed by macrophages. Here we investigate the role of TLR4 in the non-opsonic phagocytosis of C. neoformans. We find that loss of TLR4 function unexpectedly increases phagocytosis of non-opsonised cryptococci by murine and human macrophages. The increased phagocytosis observed in Tlr4-/- cells was dampened by pre-treatment of macrophages with oxidised-LDL, a known ligand of scavenger receptors. The scavenger receptor, macrophage scavenger receptor 1 (MSR1) (also known as SR-A1 or CD204) was upregulated in Tlr4-/- macrophages. Genetic ablation of MSR1 resulted in a 75% decrease in phagocytosis of non-opsonised cryptococci, strongly suggesting that it is a key non-opsonic receptor for this pathogen. We go on to show that MSR1-mediated uptake likely involves the formation of a multimolecular signalling complex involving FcγR leading to SYK, PI3K, p38 and ERK1/2 activation to drive actin remodelling and phagocytosis. Altogether, our data indicate a hitherto unidentified role for TLR4/MSR1 crosstalk in the non-opsonic phagocytosis of C. neoformans.

Keywords
  • Animals
  • Cryptococcosis
  • Cryptococcus neoformans
  • Humans
  • Macrophages / microbiology
  • Mice
  • Phagocytosis
  • Scavenger Receptors, Class A / metabolism
  • Toll-Like Receptor 4 / genetics
Affiliation entities Not a UNIGE publication
Funding
  • Biotechnology and Biological Sciences Research Council [BB/V000276/1]
  • National Centre for the Replacement, Refinement and Reduction of Animals in Research [NC/V001019/1]
  • European Research Council [614562]
  • Medical Research Council [MR/T029323/1]
Citation (ISO format)
ONYISHI, Chinaemerem U et al. Toll-like receptor 4 and macrophage scavenger receptor 1 crosstalk regulates phagocytosis of a fungal pathogen. In: Nature communications, 2023, vol. 14, n° 1, p. 4895. doi: 10.1038/s41467-023-40635-w
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Article (Published version)
Identifiers
Additional URL for this publicationhttps://www.nature.com/articles/s41467-023-40635-w
Journal ISSN2041-1723
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24downloads

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