Figure 2. Increased anti-microbial effect of macrophages by butyrate. Butyrate activates AMPK which blocks mTOR activity. Butyrate also blocks mTOR activity through inhibiting PI3K/Akt and MAPK activities. The mTOR blocks LC3, which stimulates ROS to increase phagocytosis. The mTOR can increase the production of IL-6 and TNF-α, which activate mTOR upsteam pathways PI3K/Akt and MAPK to form feed-forward regulation loop.

AMPK, adenosine monophosphate-activated protein kinase; LC3, microtubule-associated protein 1A/1B-light chain 3.