Prostaglandin E synthase

Enzyme involved in the synthesis of prostaglandin E2

Prostaglandin E synthase (PGES) is an enzyme that plays a crucial role in the biosynthesis of prostaglandin E2 (PGE2), a bioactive lipid that mediates various physiological and pathological processes. PGE2 is involved in inflammation, fever, pain, and the regulation of immune responses.

Structure and Function

Prostaglandin E synthase is a member of the glutathione-dependent peroxidase family. It catalyzes the isomerization of prostaglandin H2 (PGH2) to PGE2. This reaction is a key step in the arachidonic acid metabolic pathway, which is responsible for the production of various eicosanoids.

There are three known isoforms of PGES:

• Microsomal prostaglandin E synthase-1 (mPGES-1): This isoform is inducible and is often upregulated in response to pro-inflammatory stimuli. It is primarily associated with the production of PGE2 during inflammation.
• Microsomal prostaglandin E synthase-2 (mPGES-2): This isoform is constitutively expressed and is thought to play a role in maintaining basal levels of PGE2.
• Cytosolic prostaglandin E synthase (cPGES): This isoform is also constitutively expressed and is involved in the immediate production of PGE2 in response to cellular stimuli.

Biological Role

PGE2, the product of PGES activity, is a potent mediator of inflammation and is involved in the pathogenesis of various diseases, including arthritis, cancer, and cardiovascular disease. It exerts its effects by binding to specific prostaglandin receptors on the surface of target cells, leading to diverse biological responses.

Inflammation and Pain

PGE2 is a key mediator of the inflammatory response. It promotes vasodilation, increases vascular permeability, and sensitizes nociceptors, leading to pain and swelling. Inhibitors of PGES, particularly mPGES-1, are being investigated as potential anti-inflammatory and analgesic agents.

Fever

PGE2 is also involved in the regulation of body temperature. It acts on the hypothalamus to induce fever in response to pyrogens.

Cancer

Elevated levels of PGE2 have been associated with the progression of various cancers. PGE2 promotes tumorigenesis by enhancing cell proliferation, inhibiting apoptosis, and modulating the immune response.

Clinical Significance

Given its role in inflammation and disease, PGES is a target for drug development. Selective inhibitors of mPGES-1 are being explored for their potential to treat inflammatory diseases without the side effects associated with traditional nonsteroidal anti-inflammatory drugs (NSAIDs), which inhibit cyclooxygenase enzymes.

Related Pages

• Prostaglandin E2
• Arachidonic acid
• Cyclooxygenase
• Eicosanoids
• Inflammation