Ectopic Expression of C-Type Lectin Mincle Renders Mice Susceptible to Staphylococcal Pneumonia

Staphylococcus aureus is a prevalent pathogen in pneumonia and harbors glycolipids, which may serve as molecular patterns in Mincle (macrophage-inducible C-type lectin)-dependent pathogen recognition. We examined the role of Mincle in lung defense against S aureus in wild-type (WT), Mincle knockout (KO), and Mincle transgenic (tg) mice. Two glycolipids, glucosyl-diacylglycerol (Glc-DAG) and diglucosyl-diacylglycerol (Glc2-DAG), were purified, of which only Glc-DAG triggered Mincle reporter cell activation and professional phagocyte responses. Proteomic profiling revealed that Glc2-DAG blocked Glc-DAG-induced cytokine responses, thereby acting as inhibitor of Glc-DAG/Mincle signaling. WT mice responded to S aureus with a similar lung pathology as Mincle KO mice, most likely due to Glc2-DAG-dependent inhibition of Glc-DAG/Mincle signaling. In contrast, ectopic Mincle expression caused severe lung pathology in S aureus-infected mice, characterized by bacterial outgrowth and fatal pneumonia. Collectively, Glc2-DAG inhibits Glc-DAG/Mincle-dependent responses in WT mice, whereas sustained Mincle expression overrides Glc2-DAG-mediated inhibitory effects, conferring increased host susceptibility to S aureus.

• Hollwedel, F. D.
• Maus, R.
• Stolper, J.
• Iwai, S.
• Kasai, H.
• Holtfreter, S.
• Pich, A.
• Neubert, L.
• Welte, T.
• Yamasaki, S.
• Maus, U. A.