Lysosomal regulation of extracellular vesicle excretion during D-ribose-induced NLRP3 inflammasome activation in podocytes

Jinni Hong, Owais M. Bhat, Guangbi Li, Sara K. Dempsey, Qinghua Zhang, Joseph K. Ritter, Weiwei Li, Pin Lan Li

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

The NLRP3 inflammasome is activated in the cytoplasm of cells and its products such as IL-1β are exported through a non-classical ER-Golgi pathway. Several mechanistically distinct models including exocytosis of secretory lysosomes, microvesicles (MVs) and extracellular vehicles (EVs) have been proposed for their release. In this study, we hypothesized that the NLRP3 inflammasome product, IL-1β in response to exogenously administrated and endogenously produced D-ribose stimulation is released via extracellular vesicles including EVs via a sphingolipid-mediated molecular mechanisms controlling lysosome and multivesicular body (MVB) interaction. First, we demonstrated that both endogenous and exogenous D-ribose induced NLRP3 inflammasome activation to produce IL-1β, which was released via EVs in podocytes. Then, we found that colocalization of marker MVB marker VPS16 with IL-1β within podocytes increased upon D-ribose stimulation, which was accompanied by decreased colocalization of lysosome marker Lamp-1 and VPS16, suggesting decrease in MVB inclusion of IL-1β due to reduced lysosome and MVB interaction. All these changes were mimicked and accelerated by lysosome v-ATPase inhibitor, bafilomycin. Moreover, ceramide in podocytes was found elevated upon D-ribose stimulation, and prior treatments of podocyte with acid sphingomyelinase (Asm) inhibitor, amitriptyline, acid ceramidase (AC) inducer, genistein, or AC CRISPR/cas9 activation plasmids were found to decrease D-ribose-induced ceramide accumulation, EVs release and IL-1β secretion due to reduced interactions of lysosome with MVBs. These results suggest that inflammasome-derived products such as IL-1β during D-ribose stimulation are released via EVs, in which lysosomal sphingolipid-mediated regulation of lysosome function plays an important role.

Original languageEnglish (US)
Pages (from-to)849-860
Number of pages12
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1866
Issue number5
DOIs
StatePublished - May 2019
Externally publishedYes

Keywords

  • Ceramide
  • D-Ribose
  • Extracellular vehicles
  • Glomeruli
  • IL-1β
  • Inflammasome
  • Podocytes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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