Leukotriene/Lipoxin GPCR Family Subtypes and Products

What Are Leukotriene/Lipoxin Receptors?

Leukotriene receptors are a family of G protein-coupled receptors (GPCRs) comprised of four receptor subtypes: leukotriene B4 receptors (BLTs) and cysteinyl leukotriene receptors (CysLTs), in addition to mediator proteins oxoeicosanoid (OXE) receptor, and formyl peptide receptor 2 (FPR2/ALX). BLT receptors (BLT1 and BLT2) are involved in immunomodulation and chemotaxis, and are vital in understanding the mechanisms behind diseases such as asthma, arthritis, aortic aneurysms, cancer, and sclerosis. CysLT receptors (CysLT₁ and CysLT₂) are involved in smooth muscle contraction and the regulation of vascular permeability. CysLT antagonists are being used clinically for asthma and allergic rhinitis, and research is being done to determine the therapeutic application of CysLT antagonists for stroke prevention. Research is also being done into the use of OXE receptor antagonists as treatments for cancer and eosinophilic diseases.

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Leukotriene/Lipoxin Receptor Information

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BLT1

BLT2

CysLT1

CysLT2

Leukotriene B4 (LTB4) is a potent lipid mediator of allergic and inflammatory reactions, as well as a modulator of immune responses. Two types of plasma membrane receptors for LTB4 have been described on human neutrophils. The high-affinity human leukocyte LTB4 receptor, BLT1 (or LTB4R) mediates aggregation, chemotaxis, chemokinesis, and increased adherence to surfaces, whereas the low-affinity receptor mediates degranulation and increased oxidative metabolism. BLT1 mRNA is expressed in leukocytes and to a lesser degree in spleen and thymus. Studies in mice with disrupted BLT1 gene indicate a major role for BLT1 in acute inflammation and immediate hypersensitivity, as well as in leukocyte functions such as chemotaxis and firm adhesion to endothelium in response to LTB4.

BLT2 (or LTB4R2) mediates degranulation and increased oxidative metabolism. BLT2 is expressed ubiquitously with the highest expression in spleen and has a broader ligand specificity for various eicosanoids. Cells expressing BLT2 exhibited LTB4-induced chemotaxis, calcium mobilization, and inhibition of adenylyl cyclase. BLT2 provides a novel target for anti-inflammatory therapy and promises to expand our knowledge of LTB4 function.

CysLTR1 (Cysteinyl leukotriene receptor 1) is also known as LTD4 receptor (leukotriene D4 receptor), HG55 or HMTMF81. It is a receptor for cysteinyl leukotrienes and has highest affinity to leukotriene D4 (LTD4). The receptor mediates contraction and proliferation of smooth muscle, edema, eosinophil migration and damage to the mucus layer in the lung caused by LTD4. Several antagonists, such as montelukast (Singulair), zafirlukast (Accolate) and pranlukast (Onon), are used in the treatment of asthma.

Cysteinyl leukotriene receptor 2 (CysLTR2) is a receptor for cysteinyl leukotrienes. There are two receptors for cysteinyl leukotrienes, CysLTR1 and CysLTR2. CysLTRs have a clear role in pathophysiological conditions such as asthma, allergic rhinitis and other nasal allergies, and have been implicated in a number of inflammatory conditions in cardiovascular and gastrointestinal diseases.

Leukotriene/Lipoxin Cell Lines

Receptor Family	Receptor	Species	Parental	Stable Cell Lines	Division-Arrested Cells	Membranes
Leukotriene/Lipoxin	BLT1	human	HEK293T	H1165a	DH1165a	H1165a
	BLT2	human	HEK293T	C1272	DC1272	MC1272
	BLT2	human	HEK293T	C1272A	DC1272A	MC1272A
	BLT2	human	HEK293T	C1272b	DC1272b	MC1272b
	BLT2	human	HEK293T	C1272c	DC1272c	MC1272c
	BLT2	monkey	HEK293T	Cp1272a	DCp1272a	MCp1272a
	BLT2	monkey	HEK293T	Cp1272	DCp1272	MCp1272
	BLT2	mouse	HEK293T	Cm1272a	DCm1272a	MCm1272a
	BLT2	mouse	HEK293T	Cm1272	DCm1272	MCm1272
	CysLT1	human	HEK293T	C1308	DC1308	MC1308
	CysLT2	human	HEK293T	C1307	DC1307	MC1307
	OXE	human	HEK293T