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Androgen insensitivity syndrome (AIS) is an intersex condition occurring in 1:20,000 individuals to 1:64,000, resulting in the partial or complete inability of the cell to respond to androgens. The unresponsiveness of the cell to the presence of androgenic hormones can impair or prevent the masculinization of male genitalia in the developing fetus, as well as impairing or preventing the development of male secondary sexual characteristics at puberty, but does not significantly impair female genital or sexual development. As such, the insensitivity to androgens is clinically significant only when it occurs in genetic males. Clinical phenotypes in these individuals range from a typical male habitus with mild spermatogenic defect or reduced secondary terminal hair, to a full female habitus, despite the presence of a Y-chromosome.
The classical complement pathway is one of three pathways which activate the complement system, which is part of the immune system. The classical complement pathway is initiated by antigen-antibody complexes with the antibody isotypes IgG and IgM.
Anaphylatoxins, or complement peptides, are fragments that are produced as part of the activation of the complement system. Complement components C3, C4 and C5 are large glycoproteins that have important functions in the immune response and host defense. They have a wide variety of biological activities and are proteolytically activated by cleavage at a specific site, forming a- and b-fragments. A-fragments form distinct structural domains of approximately 76 amino acids, coded for by a single exon within the complement protein gene. The C3a, C4a and C5a components are referred to as anaphylatoxins: they cause smooth muscle contraction, vasodilation, histamine release from mast cells, and enhanced vascular permeability. They also mediate chemotaxis, inflammation, and generation of cytotoxic oxygen radicals. The proteins are highly hydrophilic, with a mainly alpha-helical structure held together by 3 disulfide bridges.
The androgen receptor (AR), also known as NR3C4, is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone in the cytoplasm and then translocating into the nucleus. The androgen receptor is most closely related to the progesterone receptor, and progestins in higher dosages can block the androgen receptor.
C5a is a protein fragment released from cleavage of complement component C5 by protease C5-convertase into C5a and C5b fragments. C5b is important in late events of the complement cascade, an orderly series of reactions which coordinates several basic defense mechanisms, including formation of the Membrane Attack Complex (MAC), one of the most basic weapons of the innate immune system, formed as an automatic response to intrusions from foreign particles and microbial invaders. It essentially pokes microscopic pinholes in these foreign objects, causing loss of water and sometimes death. C5a, the other cleavage product of C5, acts as a highly inflammatory peptide, encouraging complement activation, formation of the MAC, attraction of innate immune cells, and histamine release involved in allergic responses. The origin of C5 is in the hepatocyte, but its synthesis can also be found in macrophages, where it may cause local increase of C5a. C5a is a chemotactic agent and an anaphylatoxin; it is essential in the innate immunity but it is also linked with the adaptive immunity. The increased production of C5a is connected with a number of inflammatory diseases.
Complement component 5 is a protein that in humans is encoded by the C5 gene.
The C3a receptor also known as complement component 3a receptor 1 (C3AR1) is a G protein-coupled receptor protein involved in the complement system.
The C5a receptor also known as complement component 5a receptor 1 (C5AR1) or CD88 is a G protein-coupled receptor for C5a. It functions as a complement receptor. C5a receptor modulates inflammatory responses, obesity, development and cancers.
C-C chemokine receptor type 1 is a protein that in humans is encoded by the CCR1 gene.
N-formyl peptide receptor 3 (FPR3) is a receptor protein that in humans is encoded by the FPR3 gene.
P2Y purinoceptor 14 is a protein that in humans is encoded by the P2RY14 gene.
C5a anaphylatoxin chemotactic receptor C5a2 also known as C5L2, G protein-coupled receptor 77, is a protein that in humans is encoded by the C5AR2 gene.
Rhodopsin-like receptors are a family of proteins that comprise the largest group of G protein-coupled receptors.
C3a is one of the proteins formed by the cleavage of complement component 3; the other is C3b. C3a is a 77 residue anaphylatoxin that binds to the C3a receptor (C3aR), a class A G protein-coupled receptor. It plays a large role in the immune response.
AR-A000002 is a drug which is one of the first compounds developed to act as a selective antagonist for the serotonin receptor 5-HT1B, with approximately 10x selectivity for 5-HT1B over the closely related 5-HT1D receptor. It has been shown to produce sustained increases in levels of serotonin in the brain, and has anxiolytic effects in animal studies.
EPI-001 is the first inhibitor of the androgen receptor amino-terminal domain. The single stereoisomer of EPI-001, EPI-002, is a first-in-class drug that the USAN council assigned a new stem class "-aniten" and the generic name "ralaniten". This distinguishes the anitens novel molecular mechanism from anti androgens that bind the C-terminus ligand-binding domain and have the stem class "lutamide". EPI-001 and its stereoisomers and analogues were discovered by Dr. Marianne Sadar and Dr. Raymond Andersen who co-founded the pharmaceutical company ESSA Pharma Inc for the clinical development of anitens for the treatment of castration-resistant prostate cancer (CRPC).
Formyl peptide receptor 1 is a cell surface receptor protein that in humans is encoded by the formyl peptide receptor 1 (FPR1) gene. This gene encodes a G protein-coupled receptor cell surface protein that binds and is activated by N-Formylmethionine-containing oligopeptides, particularly N-Formylmethionine-leucyl-phenylalanine (FMLP). FPR1 is prominently expressed by mammalian phagocytic and blood leukocyte cells where it functions to mediate these cells' responses to the N-formylmethionine-containing oligopeptides which are released by invading microorganisms and injured tissues. FPR1 directs these cells to sites of invading pathogens or disrupted tissues and then stimulates these cells to kill the pathogens or to remove tissue debris; as such, it is an important component of the innate immune system that operates in host defense and damage control.
YK-11 is a synthetic steroidal selective androgen receptor modulator (SARM). It is a gene-selective partial agonist of the androgen receptor (AR) and does not induce the physical interaction between the NTD/AF1 and LBD/AF2, which is required for full transactivation of the AR. The drug has anabolic activity in vitro in C2C12 myoblasts and shows greater potency than dihydrotestosterone (DHT) in this regard.
RU-59063 is a nonsteroidal androgen or selective androgen receptor modulator (SARM) which was first described in 1994 and was never marketed. It was originally thought to be a potent antiandrogen, but subsequent research found that it actually possesses dose-dependent androgenic activity, albeit with lower efficacy than dihydrotestosterone (DHT). The drug is an N-substituted arylthiohydantoin and was derived from the first-generation nonsteroidal antiandrogen (NSAA) nilutamide. The second-generation NSAAs enzalutamide, RD-162, and apalutamide were derived from RU-59063.
5α-Dihydroethisterone is an active metabolite of the formerly clinically used but now-discontinued progestin ethisterone and the experimental and never-marketed hormonal antineoplastic agent ethynylandrostanediol (HE-3235). Its formation from its parent drugs is catalyzed by 5α-reductase in tissues that express the enzyme in high amounts like the liver, skin, hair follicles, and prostate gland. 5α-DHET has significant affinity for steroid hormone receptors and may contribute importantly to the activities of its parent drugs.
References
- ↑ Fukuoka Y, Nielsen LP, Hugli TE (1989). "Characterization of receptors to the anaphylatoxins on isolated cells". Dermatologica. 179 Suppl 1: 35–40. doi:10.1159/000248446. PMID 2528484.
