Chemical analysis of a mycolic acid-arabinogalactan-mucopeptide complex of mycobacterial cell wall

AbstractMycobacterial cell-wall glycolipids elicit an anti-mycobacterial immune response via FcRγ-associated C-type lectin receptors, including Mincle, and caspase-recruitment domain family member 9 (CARD9). Additionally, mycobacteria harbor immuno-evasive cell-wall lipids associated with virulence and latency; however, a mechanism of action is unclear. Here, we show that the DAP12-associated triggering receptor expressed on myeloid cells 2 (TREM2) recognizes mycobacterial cell-wall mycolic acid (MA)-containing lipids and suggest a mechanism by which mycobacteria control host immunity via TREM2. Macrophages respond to glycosylated MA-containing lipids in a Mincle/FcRγ/CARD9-dependent manner to produce inflammatory cytokines and recruit inducible nitric oxide synthase (iNOS)-positive mycobactericidal macrophages. Conversely, macrophages respond to non-glycosylated MAs in a TREM2/DAP12-dependent but CARD9-independent manner to recruit iNOS-negative mycobacterium-permissive macrophages. Furthermore, TREM2 deletion enhances Mincle-induced macrophage activation in vitro and inflammation in vivo and accelerates the elimination of mycobacterial infection, suggesting that TREM2-DAP12 signaling counteracts Mincle-FcRγ-CARD9-mediated anti-mycobacterial immunity. Mycobacteria, therefore, harness TREM2 for immune evasion.

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MmpL11 Protein Transports Mycolic Acid-containing Lipids to the Mycobacterial Cell Wall and Contributes to Biofilm Formation in Mycobacterium smegmatis

Journal of Biological Chemistry ◽

10.1074/jbc.m113.473371 ◽

2013 ◽

Vol 288 (33) ◽

pp. 24213-24222 ◽

Cited By ~ 66

Author(s):

Sophia A. Pacheco ◽

Fong-Fu Hsu ◽

Katelyn M. Powers ◽

Georgiana E. Purdy

Keyword(s):

Cell Wall ◽

Mycobacterium Smegmatis ◽

Biofilm Formation ◽

Mycolic Acid ◽

Mycobacterial Cell ◽

Mycobacterial Cell Wall

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Mycobacteriophage Ms6 LysB specifically targets the outer membrane of Mycobacterium smegmatis

Microbiology ◽

10.1099/mic.0.032821-0 ◽

2010 ◽

Vol 156 (5) ◽

pp. 1497-1504 ◽

Cited By ~ 36

Author(s):

Filipa Gil ◽

Anna E. Grzegorzewicz ◽

Maria João Catalão ◽

João Vital ◽

Michael R. McNeil ◽

...

Keyword(s):

Cell Wall ◽

Outer Membrane ◽

Mycobacterium Smegmatis ◽

Mycolic Acid ◽

Head Group ◽

Lipolytic Enzyme ◽

Ester Bond ◽

Mycolic Acids ◽

Mycobacterial Cell ◽

Mycobacterial Cell Wall

LysB, a mycobacteriophage Ms6-encoded protein, was previously identified as a lipolytic enzyme able to hydrolyse the ester bond in lipase and esterase substrates. In the present work, we show that LysB can hydrolyse lipids containing mycolic acids from the outer membrane of the mycobacterial cell wall. LysB was shown to hydrolyse the mycolic acids from the mycolyl-arabinogalactan–peptidoglycan complex where the mycolates of the inner leaflet of the outer membrane are covalently attached to an arabinosyl head group. In addition, treatment of the extractable lipids from Mycobacterium smegmatis, Mycobacterium bovis BCG and Mycobacterium tuberculosis H37Ra with LysB showed that trehalose 6,6′-dimycolate (TDM), a trehalose diester of two mycolic acid molecules, was hydrolysed by the enzyme. We have also determined the structures of the mycolic acid molecules that form the M. smegmatis TDM. The identification of a phage-encoded enzyme that targets the outer membrane of the mycobacterial cell wall enhances our understanding of the mechanism of mycobacteriophage lysis.

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Contrasting roles of the innate receptors TREM2 versus Mincle in the recognition and response of macrophages to mycolic acid-containing lipids in mycobacterial cell walls

10.21203/rs.3.rs-37581/v1 ◽

2020 ◽

Author(s):

Ei'ichi Iizasa ◽

Yasushi Chuma ◽

Takayuki Uematsu ◽

Mio Kubota ◽

Hiroaki Kawaguchi ◽

...

Keyword(s):

Cell Wall ◽

Mycobacterial Infection ◽

Mycolic Acid ◽

Dependent Manner ◽

Independent Manner ◽

Lectin Receptors ◽

Mycobacterial Cell ◽

Mycobacterial Cell Wall

Abstract Mycobacterial cell-wall glycolipids elicit an anti-mycobacterial immune response via FcRγ-associated C-type lectin receptors, including Mincle, and caspase-recruitment domain family member 9 (CARD9). Additionally, mycobacteria harbor immuno-evasive cell-wall lipids associated with virulence and latency; however, their mechanism of action remains unclear. Here, we show that the DAP12-associated triggering receptor expressed on myeloid cells 2 (TREM2) recognizes mycobacterial cell-wall mycolic acid (MA)-containing lipids and suggest a mechanism by which mycobacteria control host immunity via TREM2. Macrophages responded to glycosylated MA-containing lipids in a Mincle/FcRγ/CARD9-dependent manner to produce inflammatory cytokines and recruit inducible nitric oxide synthase (iNOS)-positive mycobactericidal macrophages. Conversely, macrophages responded to non-glycosylated MAs in a TREM2/DAP12-dependent but CARD9-independent manner to recruit iNOS-negative mycobacterium-permissive macrophages. Furthermore, TREM2 deletion enhanced Mincle-induced macrophage activation in vitro and inflammation in vivo and accelerated the elimination of mycobacterial infection, suggesting that TREM2-DAP12 signaling counteracts Mincle-FcRγ-CARD9-mediated anti-mycobacterial immunity. Mycobacteria, therefore, harness TREM2 for immune evasion.

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Mycolic Acid Structure Determines the Fluidity of the Mycobacterial Cell Wall

Journal of Biological Chemistry ◽

10.1074/jbc.271.47.29545 ◽

1996 ◽

Vol 271 (47) ◽

pp. 29545-29551 ◽

Cited By ~ 184

Author(s):

Jun Liu ◽

Clifton E. Barry ◽

Gurdyal S. Besra ◽

Hiroshi Nikaido

Keyword(s):

Cell Wall ◽

Mycolic Acid ◽

Mycobacterial Cell ◽

Mycobacterial Cell Wall ◽

Acid Structure

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Structures of the mycobacterial membrane protein MmpL3 reveal its mechanism of lipid transport

PLoS Biology ◽

10.1371/journal.pbio.3001370 ◽

2021 ◽

Vol 19 (8) ◽

pp. e3001370

Author(s):

Chih-Chia Su ◽

Philip A. Klenotic ◽

Meng Cui ◽

Meinan Lyu ◽

Christopher E. Morgan ◽

...

Keyword(s):

Cell Wall ◽

Membrane Protein ◽

Md Simulations ◽

Mycolic Acid ◽

Lipid Transport ◽

X Ray Crystallography ◽

Trehalose Dimycolate ◽

Mycobacterial Cell ◽

Mycobacterial Cell Wall ◽

Trehalose Monomycolate

The mycobacterial membrane protein large 3 (MmpL3) transporter is essential and required for shuttling the lipid trehalose monomycolate (TMM), a precursor of mycolic acid (MA)-containing trehalose dimycolate (TDM) and mycolyl arabinogalactan peptidoglycan (mAGP), in Mycobacterium species, including Mycobacterium tuberculosis and Mycobacterium smegmatis. However, the mechanism that MmpL3 uses to facilitate the transport of fatty acids and lipidic elements to the mycobacterial cell wall remains elusive. Here, we report 7 structures of the M. smegmatis MmpL3 transporter in its unbound state and in complex with trehalose 6-decanoate (T6D) or TMM using single-particle cryo-electron microscopy (cryo-EM) and X-ray crystallography. Combined with calculated results from molecular dynamics (MD) and target MD simulations, we reveal a lipid transport mechanism that involves a coupled movement of the periplasmic domain and transmembrane helices of the MmpL3 transporter that facilitates the shuttling of lipids to the mycobacterial cell wall.

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