Lipopolysaccharide (LPS) and anionic microbial surface components (LPS)

Lipopolysaccharide (LPS) and other anionic microbial surface components, such as lipoteichoic acid, are essential structural molecules of the bacterial cell envelope that play a pivotal role in host-pathogen interactions [Raetz & Whitfield, 2002, Annu Rev Biochem]. LPS, often referred to as endotoxin, is the primary component of the outer membrane of Gram-negative bacteria and is composed of lipid A, a core oligosaccharide, and an O-antigen [Putnam et al., 2022, Front Cell Infect Microbiol]. These molecules function as potent pathogen-associated molecular patterns (PAMPs), which are recognized by host pattern recognition receptors like Toll-like receptor 4 (TLR4) and scavenger receptors, initiating an innate immune response [Opal, 2010, Chest]. In the context of disease, the systemic release of these components can lead to uncontrolled inflammation, sepsis, and life-threatening septic shock [Hotchkiss et al., 2013, Nat Rev Dis Primers]. Pharmacologically, these components are targeted by cationic antibiotics such as polymyxins (Polymyxin B and Colistin), which bind to the anionic phosphate groups of LPS to disrupt the bacterial membrane [Velkov et al., 2013, J Med Chem]. Additionally, therapeutic efforts have focused on neutralizing these components using antibodies, binding proteins, or detoxifying enzymes to mitigate the effects of endotoxemia [Witte et al., 2001, Langenbecks Arch Surg].

Other names

EndotoxinLipoglycanPyrogenGram-negative bacterial endotoxinLipid A-containing components

Drugs typically interact with these components through electrostatic binding to anionic groups (such as phosphate groups on Lipid A), leading to displacement of stabilizing divalent cations and subsequent disruption of bacterial membrane integrity [Velkov et al., 2013, J Med Chem]. Other mechanisms include the neutralization of the Lipid A moiety to prevent its interaction with the TLR4/MD-2 receptor complex, thereby inhibiting pro-inflammatory signaling [Opal, 2010, Chest].