A terpene nucleoside from M. tuberculosis induces lysosomal lipid storage in foamy macrophages
Melissa Bedard, … , Nicole van der Wel, D. Branch Moody
Melissa Bedard, … , Nicole van der Wel, D. Branch Moody
Published February 9, 2023
Citation Information: J Clin Invest. 2023;133(6):e161944. https://doi.org/10.1172/JCI161944.
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Research Article Infectious disease Microbiology

A terpene nucleoside from M. tuberculosis induces lysosomal lipid storage in foamy macrophages

Abstract

Induction of lipid-laden foamy macrophages is a cellular hallmark of tuberculosis (TB) disease, which involves the transformation of infected phagolysosomes from a site of killing into a nutrient-rich replicative niche. Here, we show that a terpenyl nucleoside shed from Mycobacterium tuberculosis, 1-tuberculosinyladenosine (1-TbAd), caused lysosomal maturation arrest and autophagy blockade, leading to lipid storage in M1 macrophages. Pure 1-TbAd, or infection with terpenyl nucleoside–producing M. tuberculosis, caused intralysosomal and peribacillary lipid storage patterns that matched both the molecules and subcellular locations known in foamy macrophages. Lipidomics showed that 1-TbAd induced storage of triacylglycerides and cholesterylesters and that 1-TbAd increased M. tuberculosis growth under conditions of restricted lipid access in macrophages. Furthermore, lipidomics identified 1-TbAd–induced lipid substrates that define Gaucher’s disease, Wolman’s disease, and other inborn lysosomal storage diseases. These data identify genetic and molecular causes of M. tuberculosis–induced lysosomal failure, leading to successful testing of an agonist of TRPML1 calcium channels that reverses lipid storage in cells. These data establish the host-directed cellular functions of an orphan effector molecule that promotes survival in macrophages, providing both an upstream cause and detailed picture of lysosome failure in foamy macrophages.

Authors

Melissa Bedard, Sanne van der Niet, Elliott M. Bernard, Gregory Babunovic, Tan-Yun Cheng, Beren Aylan, Anita E. Grootemaat, Sahadevan Raman, Laure Botella, Eri Ishikawa, Mary P. O’Sullivan, Seónadh O’Leary, Jacob A. Mayfield, Jeffrey Buter, Adriaan J. Minnaard, Sarah M. Fortune, Leon O. Murphy, Daniel S. Ory, Joseph Keane, Sho Yamasaki, Maximiliano G. Gutierrez, Nicole van der Wel, D. Branch Moody

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Figure 8

TRPML1 agonism prevents 1-TbAd effects on macrophages.

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TRPML1 agonism prevents 1-TbAd effects on macrophages. (A) Human M1 macr...
(A) Human M1 macrophages were pretreated with TRPML1 agonist for 1 hour, followed by incubation with 10 μM 1-TbAd for 4 hours. Scale bar: 10 μm. (B) Cells treated as in A were labeled with 10 nm immunogold and anti-LAMP1. Insets of representative images show electron-lucent compartment inclusions (upper right), while agonist-treated macrophages contained smaller electron-lucent compartments (lower right). The area (μm2) of electron-lucent lysosomal compartments was determined using the least-squares mean post test with adjustment by Tukey’s method after factorial ANOVA of a linear mixed model fit that treated each cell as a random effect variable. Scale bars: 2 μm and 500 nm (enlarged insets). (C) Human M1 macrophages loaded with the C12FDG were treated as in A in biological triplicate in 2 experiments. (D) Human M1 macrophages treated as in A were subjected to BODIPY and anti-LAMP1 staining followed by BODIPY quantitation with the Kruskal-Wallis test. The results are representative of 3 experiments. Scale bar: 10 μm.