Lanosterol Modulates TLR4-Mediated Innate Immune Responses in Macrophages

Publication date: 27 June 2017
Source:Cell Reports, Volume 19, Issue 13
Author(s): Elisa Araldi, Marta Fernández-Fuertes, Alberto Canfrán-Duque, Wenwen Tang, Gary W. Cline, Julio Madrigal-Matute, Jordan S. Pober, Miguel A. Lasunción, Dianqing Wu, Carlos Fernández-Hernando, Yajaira Suárez
Macrophages perform critical functions in both innate immunity and cholesterol metabolism. Here, we report that activation of Toll-like receptor 4 (TLR4) in macrophages causes lanosterol, the first sterol intermediate in the cholesterol biosynthetic pathway, to accumulate. This effect is due to type I interferon (IFN)-dependent histone deacetylase 1 (HDAC1) transcriptional repression of lanosterol-14α-demethylase, the gene product of Cyp51A1. Lanosterol accumulation in macrophages, because of either treatment with ketoconazole or induced conditional disruption of Cyp51A1 in mouse macrophages in vitro, decreases IFNβ-mediated signal transducer and activator of transcription (STAT)1-STAT2 activation and IFNβ-stimulated gene expression. These effects translate into increased survival to endotoxemic shock by reducing cytokine secretion. In addition, lanosterol accumulation increases membrane fluidity and ROS production, thus potentiating phagocytosis and the ability to kill bacteria. This improves resistance of mice to Listeria monocytogenes infection by increasing bacterial clearance in the spleen and liver. Overall, our data indicate that lanosterol is an endogenous selective regulator of macrophage immunity.

Graphical abstract

Teaser

Araldi et al. find that TLR4-mediated transcriptional downregulation of Cyp51A1 induces lanosterol accumulation in macrophages, thus promoting antimicrobial activity and favoring negative feedback of type I IFN-mediated responses.


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