These mechanisms include the regulation of the TLR4 (Toll-like receptor 4) signaling pathway, which provides an inflammatory response to the lipopolysaccharide (LPS) of the cell wall of Gram-negative bacteria and is widely represented in the cytoplasmic membrane of various cell types, including macrophages, and is actively involved in the pathogenesis of both COPD and atherosclerosis. Here, TLR4 is linked to chronic obstructive pulmonary disease.