Recent advances in the design and development of small molecules targeting the TLR4 signaling pathway

Toll-like receptor-4 (TLR4) is a key pattern recognition receptor that plays an essential role in initiating innate immune responses. However, dysregulated TLR4 signaling is associated with the progression of sepsis, neurodegenerative disorders, cardiovascular and autoimmune diseases. Though the clinical progress of TLR4 inhibitors has been hindered by insufficient selectivity, poor pharmacokinetics and concerns of systemic immunosuppression, significant opportunities remain to design more selective and effective TLR4 modulators for diverse inflammatory and immune related diseases. In the past several years, diverse classes of inhibitors such as glycolipid mimetics, heterocyclic small molecules, natural product, peptides and compounds that downregulate receptor expression have shown promising biological activity in preclinical models of disease. These advancements have generated valuable insights into TLR4 recognition, signaling mechanisms and structure activity relationships. This review summarizes recent progress in the identification and design of TLR4 inhibitors, with emphasis on mechanistic characteristics, binding interactions, virtual screening methodologies and structural determinants that influence inhibitor performance. The collective evidence highlights the growing therapeutic potential of selective and broadly effective TLR4 modulators. As the field continues to advance, the further optimization of drug-like properties, in vivo efficacy and the integration of computational approaches will be essential to translate these promising candidates into clinically viable therapies.