Interleukin 20

Abstract

A structural, profile-based algorithm was used to identify interleukin 20 (IL-20), a novel IL-10 homolog. Chromosomal localization of IL-20 led to the discovery of an IL-10 family cytokine cluster. Overexpression of IL-20 in transgenic (TG) mice causes neonatal lethality with skin abnormalities including aberrant epidermal differentiation. Recombinant IL-20 protein stimulates a signal transduction pathway through STAT3 in a keratinocyte cell line, demonstrating a direct action of this ligand. An IL-20 receptor was identified as a heterodimer of two orphan class II cytokine receptor subunits. Both receptor subunits are expressed in skin and are dramatically upregulated in psoriatic skin. Taken together, these results demonstrate a role in epidermal function and psoriasis for IL-20, a novel cytokine identified solely by bioinformatics analysis.

Characterization of the Recombinant Extracellular Domains of Human Interleukin-20 Receptors and Their Complexes with Interleukin-19 and Interleukin-20

“…IL-20 plays an important role in skin biology. Overexpression of IL-20 in transgenic mice resulted in neonatal lethality with skin abnormalities, similar to those found in psoriatic skin (2). By contrast, it was reported that IL-19-overexpressing transgenic mice had no overt skin phenotype (27).…”

“…Both IL-20 and IL-24 form complexes with the receptor pair IL-22R1/IL-20R2 (25). In addition, IL-19, IL-20, and IL-24 also signal through formation of the complexes with IL-20R1/IL-20R2 (2,23,25).…”

Unique aspects of mda-7/IL-24 antitumor bystander activity: establishing a role for secretion of MDA-7/IL-24 protein by normal cells

“…RT was performed on 5 mg of total RNA with an oligo (dT) primer as described previously. cDNA corresponding to 5 ng of total RNA was amplified for 35 cycles by PCR with specific primers for IL-20R1, IL-20R2 and IL-22R1 as described (Blumberg et al, 2001). The products were analysed on ethidium bromide-stained 1% agarose gels following electrophoresis.…”

“…Based on its structure (containing an IL-10 signature motif), chromosomal location (1q32) and secretion by cells, mda-7 is now classified as part of the expanding IL-10 gene family and has been given the name IL-24 (Blumberg et al, 2001;Huang et al, 2001;Caudell et al, 2002;Pestka et al, 2003Pestka et al, , 2004Gopalkrishnan et al, 2004;Lebedeva et al, 2005a). When present at perceived physiological levels, mda-7/IL-24, which is expressed in defined tissues of the immune system (Huang et al, 2001), has immunostimulatory functions (Caudell et al, 2002;Fisher et al, 2003;Tong et al, 2005), although its precise role in modulating immune responses requires clarification.…”

The T-cell Lymphokine Interleukin-26 Targets Epithelial Cells through the Interleukin-20 Receptor 1 and Interleukin-10 Receptor 2 Chains

“…In addition, the three interferon-like cytokines molecules IL-28A, IL-28B, and IL-29 (IFN-1-3) can be included into this family because of sequence homology rather than to functional similarity (15,16). Whereas the genes for IL-19, IL-20, and IL-24 cluster near the IL-10 locus on human chromosome 1q32 (17,18), those for IL-22 and IL-26 are found close to the IFN-␥ gene on chromosome 12q15 (4, 19 -21). Correspondingly, IL-10, IL-19, IL-20, and IL-24 are primarily secreted by activated macrophages, whereas T-cells are the main source for IL-22, IL-26, and IFN-␥ (4,7,9,22,23).…”