Background:

AICAR is a cell-permeable, allosteric activator of AMP-activated protein kinase (AMPK).

AMPK is a heterodimeric protein serine/threonine kinase that regulates the energy status of cells to protect cell from metabolic stress. AMPK phosphorylates various metabolic enzymes to activate catabolic pathways (e.g. ketogenesis) and block anabolic pathways (e.g. protein synthesis).

In rat primary astrocytes, microglia, and peritoneal macrophages, AICAR does-dependently inhibits the LPS-induced production of TNFα, IL-1β, and IL-6. AICAR treatment also blocks LPS-induced nitrite production and iNOS gene expression in those cells in a dose-dependent manner by activation of AMPK. Moreover, AICAR inhibits the LPS-induced C/EBP nuclear relocation via downregulating the expression of C/EBP-δ. [1]

In LPS-injected rats, AICAR treatment abolishes LPS-mediated increased levels of IL-1β and IFN-γ in serum. AICAR treatment also strongly inhibits the LPS-induced expression of iNOS in peritoneal macrophages isolated from these rats. Furthermore, the intraperitoneal injection of LPS significantly induces the expression of TNFα, IL-1β, and IFN-γ message in the rat spleen.

Reference:
1.  Giri S, Nath N, Smith B et al. 5-aminoimidazole-4-carboxamide-1-beta-4-ribofuranoside inhibits proinflammatory response in glial cells: a possible role of AMP-activated protein kinase. J Neurosci. 2004 Jan 14;24(2):479-87.