Chemokine (C-C motif) ligand 20 (CCL20) or liver activation regulated chemokine (LARC) or Macrophage Inflammatory Protein-3 (MIP3A) is a small

cytokine Cytokines () are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are produced by a broad range of cells, including immune cells like macrophages, B cell, B lymphocytes, T cell, T lymphocytes ...

belonging to the CC chemokine family. It is strongly chemotactic for

lymphocyte A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include T cells (for cell-mediated and cytotoxic adaptive immunity), B cells (for humoral, antibody-driven adaptive immunity), an ...

s and weakly attracts

neutrophil Neutrophils are a type of phagocytic white blood cell and part of innate immunity. More specifically, they form the most abundant type of granulocytes and make up 40% to 70% of all white blood cells in humans. Their functions vary in differe ...

s. CCL20 is implicated in the formation and function of mucosal lymphoid tissues via chemoattraction of

s and

dendritic cell A dendritic cell (DC) is an antigen-presenting cell (also known as an ''accessory cell'') of the mammalian immune system. A DC's main function is to process antigen material and present it on the cell surface to the T cells of the immune system ...

s towards the

epithelial cell Epithelium or epithelial tissue is a thin, continuous, protective layer of Cell (biology), cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial (Mesothelium, mesothelial) tissues line ...

s surrounding these tissues. CCL20 elicits its effects on its target cells by binding and activating the

chemokine receptor Chemokine receptors are cytokine receptors found on the surface of certain cells that interact with a type of cytokine called a chemokine. There have been 20 distinct chemokine receptors discovered in humans. Each has a rhodopsin-like 7-tran ...

CCR6.

Gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

expression of CCL20 can be induced by

microbial A microorganism, or microbe, is an organism of microscopic size, which may exist in its single-celled form or as a colony of cells. The possible existence of unseen microbial life was suspected from antiquity, with an early attestation in ...

factors such as lipopolysaccharide (LPS), and inflammatory cytokines such as

tumor necrosis factor Tumor necrosis factor (TNF), formerly known as TNF-α, is a chemical messenger produced by the immune system that induces inflammation. TNF is produced primarily by activated macrophages, and induces inflammation by binding to its receptors o ...

and interferon-γ, and down-regulated by IL-10. CCL20 is expressed in several tissues with highest expression observed in peripheral blood

lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that includ ...

liver The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of var ...

, appendix, and

fetal A fetus or foetus (; : fetuses, foetuses, rarely feti or foeti) is the unborn offspring of a viviparous animal that develops from an embryo. Following the embryonic stage, the fetal stage of development takes place. Prenatal development is a ...

lung The lungs are the primary Organ (biology), organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the Vertebral column, backbone on either side of the heart. Their ...

and lower levels in thymus, testis, prostate and gut. The gene for CCL20 (''scya20'') is located on chromosome 2 in humans. Recent research Regional Neural Activation Defines a Gateway for Autoreactive T Cells to Cross the Blood-Brain Barrier , author = Arima, Yasunobu; Harada, Masaya; Kamimura, Daisuke; Park, Jin-Haeng; Kawano, Fuminori; Yull, Fiona E.; Kawamoto, Tadafumi; Iwakura, Yoichiro; Betz, Ulrich A.K.; Marquez, Gabriel; Blackwell, Timothy S.; Ohira, Yoshinobu; Hirano, Toshio; Murakami, Masaaki , Cell doi:10.1016/j.cell.2012.01.022 (volume 148 issue 3 pp.447 - 457) in an animal model of multiple sclerosis known as experimental autoimmune encephalitis (EAE) demonstrated that regional neural activation can create "gates" for pathogenic

CD4 In molecular biology, CD4 (cluster of differentiation 4) is a glycoprotein that serves as a co-receptor for the T-cell receptor (TCR). CD4 is found on the surface of immune cells such as helper T cells, monocytes, macrophages, and dendritic c ...

+ T cells to enter the CNS by increasing CCL20 expression, especially at L5. Sensory nerve stimulation, elicited by using muscles in the leg or electrical stimulation as in Arima et al., 2012, activates sympathetic neurons whose axons run through the dorsal root ganglia containing cell bodies of the stimulated afferent sensory nerve. Sympathetic neuronal activity activates IL-6 amplifier resulting in increased regional CCL20 expression and subsequent pathogenic CD4+ T cell accumulation at the same spinal cord level. CCL20 expression was observed to be dependent on IL-6 amplifier activation, which is dependent on

NF-κB Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a family of transcription factor protein complexes that controls transcription (genetics), transcription of DNA, cytokine production and cell survival. NF-κB is found i ...

and

STAT3 Signal transducer and activator of transcription 3 (STAT3) is a transcription factor which in humans is encoded by the ''STAT3'' gene. It is a member of the STAT protein family. Function STAT3 is a member of the STAT protein family. In respon ...

activation. This research provides evidence for a critical role for CCL20 in autoimmune pathogenesis of the central nervous system.

References

External links

* {{Chemokine receptor modulators Cytokines

References

Further reading

External links