Abstract:

Tolllike Receptor 9 (TLR9) is a member of Tolllike receptor family that use pathogen associated molecule patterns (PAMPs) as ligands. It is expressed in immune cells and senses bacterial DNA ligand to induce innate immune response. Recent studies have shown that TLR9 is also expressed in several nonimmune cells，including glomerular podocyte， and uses mitochondrial DNA as ligand to activate signaling pathways that lead to cell injury. Here, we will review the roles of TLR9 in immune cells and nonimmune cells and the underlying mechanisms.

Key words: TLR9, innate immunity, mitochondrial DNA, podocytes