Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.16 (calcineurin)
 17,112 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

At present, the first-line drugs for treating atopic dermatitis are topical corticosteroids. They are effective when used short-term; however, long-term use of the corticosteroids is associated with suppressive effects on the connective tissue, seen as skin atrophy or resistance to therapy. Currently, two topical noncorticosteroid immunomodulators tacrolimus (FK506) and pimecrolimus (SDZ ASM 981) are under development, or already on the market in some countries for atopic dermatitis. These two compounds show structural similarity. In T lymphocytes they bind to the same cellular receptor, the FK-binding protein (FKBP) or macrophilin-12. Tacrolimus shows a 3-fold greater affinity to FKBP compared with pimecrolimus. The tacrolimus/ pimecrolimus-FKBP complex further binds to calcineurin, an enzyme vital for the early activation of T cells. The consequence of calcineurin binding is a lack of activation of both T helper cell types 1 and 2. Further effects of these compounds have been suggested on other inflammatory cells, such as Langerhans cells and mast cells/basophils. In contrast to corticosteroids, no suppressive effects on connective tissue cells have been observed. Taken together, treatment of inflammation results in healing of the barrier function of the skin. This again results in reduced bioavailability of the drug, as compared with systemic use. Placebo-controlled studies have shown the efficacy of both tacrolimus (at 0.03 and 0.1%) and pimecrolimus (at 0.6 and 1%). The main adverse event in these studies has been a burning sensation and increased pruritus at the site of application. Typically, these adverse events are observed only during the first days of treatment. Long-term safety studies, of up to one year, have not revealed any new adverse events. So far, long-term use of topical noncorticosteroid compounds has not been associated with signs of immune deficiency. Although there is currently no evidence for clinically relevant, prolonged adverse effects, some of these, such as an increased risk of photocarcinogenesis, need to be monitored. There is evidence from tacrolimus studies that monotherapy results in better long-term results when compared with combination therapy with corticosteroids. Tacrolimus and pimecrolimus could replace topical corticosteroids as the first-line treatment of atopic dermatitis.
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PMID:Topical noncorticosteroid immunomodulation in the treatment of atopic dermatitis. 1211 47

In cells of the immune system that are stimulated by antigen or antigen-antibody complexes, Ca(2+) entry from the extracellular medium is driven by depletion of endoplasmic reticulum Ca(2+) stores and occurs through specialized store-operated Ca(2+) channels known as Ca(2+)-release-activated Ca(2+) (CRAC) channels. The process of store-operated Ca(2+) influx is essential for short-term as well as long-term responses by immune-system cells. Short-term responses include mast cell degranulation and killing of target cells by effector cytolytic T cells, whereas long-term responses typically involve changes in gene transcription and include T and B cell proliferation and differentiation. Transcription downstream of Ca(2+) influx is in large part funneled through the transcription factor nuclear factor of activated T cells (NFAT), a heavily phosphorylated protein that is cytoplasmic in resting cells, but that enters the nucleus when dephosphorylated by the calmodulin-dependent serine/threonine phosphatase calcineurin. The importance of the Ca(2+)/calcineurin/NFAT signalling pathway for lymphocyte activation is underscored by the finding that the underlying defect in a family with a hereditary severe combined immune deficiency (SCID) syndrome is a defect in CRAC channel function, store-operated Ca(2+) entry, NFAT activation and transcription of cytokines, chemokines and many other NFAT target genes whose transcription is essential for productive immune defence. We recently used a two-pronged genetic approach to identify Orai1 as the pore subunit of the CRAC channel. On the one hand, we initiated a positional cloning approach in which we utilised genome-wide single nucleotide polymorphism (SNP) mapping to identify the genomic region linked to the mutant gene in the SCID family described above. In parallel, we used a genome-wide RNAi screen in Drosophila to identify critical regulators of NFAT nuclear translocation and store-operated Ca(2+) entry. These approaches, together with subsequent mutational and electrophysiological analyses, converged to identify human Orai1 as a pore subunit of the CRAC channel and as the gene product mutated in the SCID patients.
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PMID:Signalling to transcription: store-operated Ca2+ entry and NFAT activation in lymphocytes. 1757 87