Particle uptake by macrophages triggers bifurcated transcriptional pathways that differentially regulate inflammation and lysosomal gene expression

Abstract

Exposure to particles is a driver of several inflammatory diseases. Here, we investigated macrophage responses to monosodium urate crystals, calcium pyrophosphate crystals, aluminum salts, and silica nanoparticles. While each particle induced a distinct gene expression pattern, we identified a common inflammatory signature and acute activation of lysosomal acidification genes. Using monosodium urate crystals as a model, we demonstrated that this lysosomal gene program is regulated by a 5'-prime-AMP-activated protein kinase (AMPK)-dependent transcriptional network, including TFEB, TFE3, and the epigenetic regulators DNA methyl transferase 3a (DNMT3A) and DOT1L. This lysosomal acidification program operates in parallel with, but largely independently of, a JNK-AP-1-dependent network driving crystal-induced chemokine and cytokine expression. These findings reveal a bifurcation in pathways governing inflammatory and lysosomal responses, offering insights for treating particle-associated diseases.

Keywords: AMPK; JNK; epigenetic regulation; lysosome; macrophages; particles; transcription.