The distinct fate of smooth and rough Mycobacterium abscessus variants inside macrophages. Issue 11 (November 2016)

• Record Type: Journal Article
• Authors: Roux, Anne-Laure; Viljoen, Albertus; Bah, Aïcha; Simeone, Roxane; Bernut, Audrey; Laencina, Laura; Deramaudt, Therese; Rottman, Martin; Gaillard, Jean-Louis; Majlessi, Laleh; Brosch, Roland; Girard-Misguich, Fabienne; Vergne, Isabelle; de Chastellier, Chantal; Kremer, Laurent; Herrmann, Jean-Louis
• Is Part Of: Open biology. Volume 6:Issue 11(2016)
• Publication Date: 2016-11
• Subjects: Mycobacterium abscessus -- macrophages -- phagosome -- innate response -- rapid-growing mycobacteria; Biology -- Periodicals; 570
• DOI: 10.1098/rsob.160185
• Languages: English
• ISSNs: 2046-2441

Abstract

Abstract : Abstract : Mycobacterium abscessus is a pathogenic, rapidly growing mycobacterium responsible for pulmonary and cutaneous infections in immunocompetent patients and in patients with Mendelian disorders, such as cystic fibrosis (CF). Mycobacterium abscessus is known to transition from a smooth (S) morphotype with cell surface-associated glycopeptidolipids (GPL) to a rough (R) morphotype lacking GPL. Herein, we show that M. abscessus S and R variants are able to grow inside macrophages and are present in morphologically distinct phagosomes. The S forms are found mostly as single bacteria within phagosomes characterized by a tightly apposed phagosomal membrane and the presence of an electron translucent zone (ETZ) surrounding the bacilli. By contrast, infection with the R form leads to phagosomes often containing more than two bacilli, surrounded by a loose phagosomal membrane and lacking the ETZ. In contrast to the R variant, the S variant is capable of restricting intraphagosomal acidification and induces less apoptosis and autophagy. Importantly, the membrane of phagosomes enclosing the S forms showed signs of alteration, such as breaks or partial degradation. Although not frequently encountered, these events suggest that the S form is capable of provoking phagosome–cytosol communication. In conclusion, M. abscessus S exhibits traits inside macrophages that are reminiscent of slow-growing mycobacterial species.