Molecular mechanisms of eucaryotic cell perception of and response to environmental signals

Abstract

Homeostasis is the state of metabolic equilibrium supporting the optimal functioning of an organism that is actively maintained by complex biological mechanisms. An organism responds to deviations from this stable situation by a coordinated sequence of systemic and metabolic changes, or by local changes such as inflammatory reactions, collectively known as the acute phase response (APR) The APR is an evolutionarily conserved mechanism aimed at reestablishing an organisms normal functioning during infection, tissue injury, chemical irritation and neoplastic disease. The initiation and progression of the APR involves a coordinated series of events, including cytokine release, endothelial-cell activation, leukocyte chemotaxis, alteration of the temperature set-point and activation of the adrenal pituitary axis which provide the necessary metabolic signals to the responding organ . The liver is a 1 major partner in APR and the blood-borne inflammatory cytokines such as Tumor Necrosis Factor, lnterleukin-1and Interleukin-6 trigger transient changes in the synthesis of numerous proteins in this organ.