PSEN1 and Alzheimer disease: For example, it has been suggested that activation of TLR2 receptor enhances the uptake of pathological Aβ by in vitro cultured microglial cells.288 In an APP/PS1 transgenic AD mice model, TLR2 knockout aggravated white matter damage and neurobehavioral functions, this process may be mediated by excess astrocyte activation.289 These conflicting results may further demonstrate that TLR signaling can be beneficial or detrimental to the host.