Therefore, TLR4 becomes a new target for treating cancer, autoimmune diseases, fibrosis, brain ischemia and neuralgia etc. So far, some TLR4 specific antagonists (e.g., eritoran, (+)- naloxone, resatorvi) have been found (Takashima et al., 2009; Matsunaga et al., 2011; Lewis et al., 2012; Shirey et al., 2013; Wang et al., 2016; Dickinson and Wondrak, 2018; Ono et al., 2020). Here, TLR4 is linked to brain ischemia.