cellular response to lipopolysaccharide

Definition

Target type: biologicalprocess

Any process that results in a change in state or activity of a cell (in terms of movement, secretion, enzyme production, gene expression, etc.) as a result of a lipopolysaccharide stimulus; lipopolysaccharide is a major component of the cell wall of gram-negative bacteria. [GOC:mah]

Cellular response to lipopolysaccharide (LPS) is a complex and highly regulated process that involves the activation of multiple signaling pathways and the production of a variety of inflammatory mediators. LPS, a potent immunostimulant found in the outer membrane of Gram-negative bacteria, is recognized by Toll-like receptor 4 (TLR4) on the surface of immune cells, particularly macrophages and dendritic cells.

Upon LPS binding, TLR4 forms a complex with its co-receptors, MD-2 and CD14, initiating downstream signaling events. This complex activates the MyD88-dependent pathway, which leads to the recruitment and activation of several adaptor proteins, including MyD88, IRAK1, IRAK4, and TRAF6. The activation of TRAF6 triggers the activation of the MAPK and NF-κB signaling pathways.

The MAPK pathway involves the phosphorylation and activation of three kinases: ERK, JNK, and p38. These kinases then translocate to the nucleus and regulate the expression of genes involved in inflammatory responses, such as cytokines and chemokines. The NF-κB pathway involves the phosphorylation and degradation of the NF-κB inhibitor, IκB, leading to the translocation of NF-κB to the nucleus where it activates the transcription of genes involved in inflammation, cell survival, and immune responses.

Activation of these signaling pathways leads to the production of various inflammatory mediators, including cytokines such as TNF-α, IL-1β, IL-6, and chemokines such as CCL2 and CXCL8. These mediators contribute to the recruitment of immune cells to the site of infection, the induction of fever, and the development of an inflammatory response.

The cellular response to LPS is also regulated by negative feedback mechanisms, ensuring that the inflammatory response is tightly controlled and does not become excessive. These mechanisms include the production of anti-inflammatory cytokines, such as IL-10, and the induction of apoptosis in activated immune cells.

In summary, cellular response to LPS is a multifaceted process involving multiple signaling pathways, inflammatory mediators, and regulatory mechanisms. This response is essential for the host's defense against Gram-negative bacterial infections, but its dysregulation can contribute to the pathogenesis of various inflammatory diseases.'
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Proteins (62)

Compounds (1,676)