IRAK4 and Alzheimer disease: Another study reported that the cerebrospinal fluid of AD individuals was specifically enriched in let-7b or let-7e [97] and interacted with TLR7 receptors as signaling molecules, further activating IRAK-4 through phosphorylation, and the activated IRAK-4 stimulates caspase-3 to activate the TLR7 signaling pathway, which eventually leads to neuronal degeneration [98].