Leukotriene C₄ (LTC₄) is a

leukotriene Leukotrienes are a family of eicosanoid inflammatory mediators produced in leukocytes by the oxidation of arachidonic acid (AA) and the essential fatty acid eicosapentaenoic acid (EPA) by the enzyme arachidonate 5-lipoxygenase. Leukotrie ...

. LTC₄ has been extensively studied in the context of

allergy Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allerg ...

and

asthma Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, c ...

. In cells of myeloid origin such as

mast cells A mast cell (also known as a mastocyte or a labrocyte) is a resident cell of connective tissue that contains many granule (cell biology), granules rich in histamine and heparin. Specifically, it is a type of granulocyte derived from the CFU-GEMM, ...

, its biosynthesis is orchestrated by translocation to the nuclear envelope along with co-localization of cytosolic phospholipase A2 (cPLA2),

Arachidonate 5-lipoxygenase Arachidonate 5-lipoxygenase, also known as ALOX5, 5-lipoxygenase, 5-LOX, or 5-LO, is a non-heme iron-containing enzyme (EC 1.13.11.34) that in humans is encoded by the ''ALOX5'' gene. Arachidonate 5-lipoxygenase is a member of the lipoxygenase fa ...

(5-LO),

5-lipoxygenase-activating protein Arachidonate 5-lipoxygenase-activating protein also known as 5-lipoxygenase activating protein, or FLAP, is a protein that in humans is encoded by the ''ALOX5AP'' gene In biology, the word gene (from , ; "... Wilhelm Johannsen coined the wor ...

(FLAP) and LTC₄ synthase (LTC₄S), which couples

glutathione Glutathione (GSH, ) is an antioxidant in plants, animals, fungi, and some bacteria and archaea. Glutathione is capable of preventing damage to important cellular components caused by sources such as reactive oxygen species, free radicals, pe ...

to an LTA₄ intermediate. The MRP1 transporter then secretes cytosolic LTC₄ and cell surface proteases further metabolize it by sequential cleavage of the γ- glutamyl and

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid ( carbamic acid is unstable), with the chemical formula NH2‐ CH2‐ COOH. Glycine is one of the proteinog ...

residues off its glutathione segment, generating the more stable products LTD₄ and LTE₄. All three leukotrienes then bind at different affinities to two G-protein coupled receptors: CYSLTR1 and CYSLTR2, triggering pulmonary

vasoconstriction Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood ve ...

and

bronchoconstriction Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath. Causes The condition has a number of causes, the most common bei ...

. In cells of non- haematopoietic lineage,

endoplasmic reticulum The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ( ...

(ER) stress and

chemotherapy Chemotherapy (often abbreviated to chemo and sometimes CTX or CTx) is a type of cancer treatment that uses one or more anti-cancer drugs (chemotherapeutic agents or alkylating agents) as part of a standardized chemotherapy regimen. Chemothe ...

induce LTC₄ biosynthesis by transcriptionally upregulating and activating the enzyme microsomal glutathione-S-transferase 2 (MGST2). ER stress and chemotherapy also trigger nuclear translocation of the two LTC₄ receptors. Acting in an intracrine manner, LTC₄ then elicits nuclear translocation of NADPH oxidase 4 (NOX4), ROS accumulation and oxidative DNA damage. Besides being a potent lipid mediator in asthma and inflammation, LTC₄ was reported to be involved in several other diseases, such as allergic airway diseases, dermatological diseases, cardiovascular diseases, liver injury, atherosclerosis and colon cancer.

References

{{Leukotrienergics Eicosanoids