Effect of LPS- tolerance on bone marrow-derived macrophages in response to skeletal muscle injury in vitro.

Macrophage tolerance induced by LPS is a typical type of innate immune memory. Macrophages are also known to play an important role in tissue repair, such as in skeletal muscle. However, it is not clear how innate immune memory affects the tissue repair capacity of macrophages. Here we report gene expression in naive and LPS-tolerant bone marrow-derived macrophages in response to skeletal muscle injury using an in vitro skeletal muscle injury and repair model. We prepared naive bone marrow-derived macrophages and those tolerated with 50 ng/ml LPS for 24 hours and added them to the skeletal muscle differentiation procedure using primary cultured cells in vitro. After skeletal muscle had differentiated sufficiently (0 days post injury: 0 dpi), muscle injury was induced by treatment with barium chloride, and muscle regeneration was observed after 6 days culture. Both naive and tolerant macrophages at 0, 1, and 6 dpi were sorted by Ly6G-, CD45+, and CD11b+ for detecting global gene expression.