Acid Sphingomyelinase Contributes to the Control of Mycobacterial Infection via a Signaling Cascade Leading from Reactive Oxygen Species to Cathepsin D

• Published in: Cells (Basel, Switzerland) Vol. 9; no. 11; p. 2406
• Main Authors: Wu, Yuqing, Li, Cao, Peng, Huiming, Swaidan, Ashraf, Riehle, Andrea, Pollmeier, Barbara, Zhang, Yang, Gulbins, Erich, Grassmé, Heike
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 03-11-2020; MDPI
• Subjects: acid sphingomyelinase (Asm); Care and treatment; cathepsin D (CTSD); Cathepsins; Cellular signal transduction; ceramide; Health aspects; macrophages; Mycobacterial infections; Mycobacterium bovis Bacillus Calmette-Guérin (BCG); Observations; Physiological aspects; Reactive oxygen species; reactive oxygen species (ROS); Sphingolipids; Germany; ceramide; macrophages; acid sphingomyelinase (Asm); Mycobacterium bovis Bacillus Calmette-Guérin (BCG); granuloma; reactive oxygen species (ROS); cathepsin D (CTSD)
• ISSN: 2073-4409; 2073-4409
• DOI: 10.3390/cells9112406

Tuberculosis, caused by
, is one of the most severe diseases worldwide. The initial pulmonary localization of the pathogen often develops into systemic infection with high lethality. The present work investigated the role of sphingolipids, specifically the function of acid sphingomyelinase (Asm) and ceramide, in infection of murine macrophages in vitro and mice in vivo with
Bacillus Calmette-Guérin (BCG). In vitro, we investigated macrophages from wild-type (wt) and Asm deficient (Asm
) mice to define signaling events induced by BCG infection and mediated by Asm. We demonstrate that infection of wt macrophages results in activation of Asm, which increases reactive oxygen species (ROS) via stimulation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase. ROS promote BCG degradation by cathepsin D. Asm deficiency in macrophages abrogates these effects. In vivo studies reveal that wt mice rapidly control BCG infection, while Asm
mice fail to control the infection and kill the bacteria. Transplantation of wt macrophages into Asm
mice reversed their susceptibility to BCG, demonstrating the importance of Asm in macrophages for defense against BCG. These findings indicate that Asm is important for the control of BCG infection.