Apelin

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Apelin
Identifiers
Symbols APLN ; APEL; XNPEP2
External IDs OMIM300297 MGI1353624 HomoloGene8498 GeneCards: APLN Gene
Orthologs
Species Human Mouse
Entrez 8862 30878
Ensembl ENSG00000171388 ENSMUSG00000037010
UniProt Q9ULZ1 Q9R0R4
RefSeq (mRNA) NM_017413 NM_013912
RefSeq (protein) NP_059109 NP_038940
Location (UCSC) Chr X:
128.78 – 128.79 Mb
Chr X:
48.03 – 48.03 Mb
PubMed search [1] [2]

Apelin (also known as APLN) is a peptide that in humans is encoded by the APLN gene.[1] Apelin is the endogenous ligand for the G-protein-coupled APJ receptor[2][3][4][5][6] that is expressed at the surface of some cell types.[7] It is widely expressed in various organs such as the heart, lung, kidney, liver, adipose tissue, gastrointestinal tract, brain, adrenal glands, endothelium, and human plasma.

Discovery[edit]

Apelin is a new peptide that was identified in 1998 by Professor M. Fujino’s team.[1]

Biosynthesis[edit]

Apelin gene encodes a pre-proprotein of 77 amino acids,[1] with a signal peptide in the N-terminal region. After translocation into the endoplasmic reticulum and cleavage of the signal peptide, the proprotein of 55 amino acids may generate several active fragments: a 36 amino acid peptide corresponding to the sequence 42-77 (apelin 36), a 17 amino acid peptide corresponding to the sequence 61-77 (apelin 17) and a 13 amino acid peptide corresponding to the sequence 65-77 (apelin 13). This latter fragment may also undergo a pyroglutamylation at the level of its N-terminal glutamine residue. However the presence and/or the concentrations of those peptides in human plasma has been questioned.[8] Recently, 46 different apelin peptides ranging from apelin 55 (proapelin) to apelin 12 have been identified in bovine colostrum, including C-ter truncated isoforms.[9]

Physiological functions[edit]

The sites of receptor expression are clearly linked to the different functions played by apelin in the organism.

Vascular[edit]

Vascular expression of the receptor[10][11] participates in the control of blood pressure[2] and its activation promotes the formation of new blood vessels (angiogenesis).[11][12][13][14] The hypotensive effect of apelin results from the activation of receptors expressed at the surface of endothelial cells.[10][11] This activation induces the release of NO,[15] a potent vasodilator, which induces relaxation of the smooth muscle cells of artery wall. Studies performed on mice knocked out for the apelin receptor gene[16] have suggested the existence of a balance between angiotensin II signalling, which increases blood pressure and apelin signalling, which lowers blood pressure. The angiogenic activity is the consequence of apelin action on the proliferation and migration of the endothelial cells. Apelin activates inside the cell transduction cascades (ERKs, Akt, and p70S6kinase phosphorylation),[12][17] which lead to the proliferation of endothelial cells and the formation of new blood vessels[13] It is interesting that knockout of apelin gene is associated with a delay in the development of the retinal vasculature.[18]

Cardiac[edit]

Apelin receptor is early expressed during the embryonic formation of the heart, where it regulates the migration of cell progenitors fated to differentiate in the contractile cells, the cardiomyocytes.[19][20] Its expression is also detected in the cardiomyocytes of the adult where apelin behaves as one of the most potent stimulator of cardiac contractility.[3][21][22] Aged apelin knockout mice develop progressive impairment of cardiac contractility.[23] Apelin acts as a mediator of the cardiovascular control, including for blood pressure and blood flow. It is one of the most potent stimulators of cardiac contractility yet identified, and plays a role in cardiac tissue remodeling. Apelin levels are increased in left ventricles of patients with chronic heart failure and also in patients with chronic liver disease.[24] It is also an adipocyte endocrine secretion, making adipocytic and circulating levels of apelin higher in obesity. Insulin exerts a positive action on adipocyte apelin production. In addition, apelin regulates fluid homeostasis. It is important in the hypothalamic regulation of food and water intake, and pituitary hormone release.

Brain[edit]

Apelin receptor is also expressed in the neurons of brain areas involved in water and food intake.[2][25][26] Apelin injection increases water intake[2] and apelin decreases in the hypothalamus the secretion of an antidiuretic hormone, vasopressin.[27] This diuretic effect of apelin in association with its hypotensive effect participates in a global manner to the homeostatic regulation of body fluids. Apelin is also detected in brain areas, which control appetite, but its effects on food intake are very contradictory.[28][29][30]

Digestive[edit]

Apelin receptor is expressed in several cell types of the gastro-intestinal tract : stomach enterochromaffine-like cells;[31][32] unknown cells of endocrine pancreas,[33] colon epithelial cells.[34] In stomach, activation of receptors on enterochromaffine-like cells by apelin secreted by parietal cells can inhibit histamine release by enterochromaffine-like cells, which in turn decreases acid secretion by parietal cells.[32] In pancreas, apelin inhibits the insulin secretion induced by glucose.[35] This inhibition reveals the functional interdependency between apelin signalling and insulin signalling observed at the adipocyte level where insulin stimulate apelin production.[36] Recently, receptor expression was also detected in skeletic muscle cells. Its activation is involved in glucose uptake and participates in the control of glucose blood levels glycemia.[37]

Bone[edit]

Receptor expression is also observed at the surface of osteoblasts, the cell progenitors involved in bone formation.[38]

References[edit]

  1. ^ a b c Tatemoto K, Hosoya M, Habata Y, Fujii R, Kakegawa T, Zou MX, Kawamata Y, Fukusumi S, Hinuma S, Kitada C, Kurokawa T, Onda H, Fujino M (1998). "Isolation and characterization of a novel endogenous peptide ligand for the human APJ receptor". Biochem. Biophys. Res. Commun. 251 (2): 471–6. doi:10.1006/bbrc.1998.9489. PMID 9792798. 
  2. ^ a b c d Lee DK, Cheng R, Nguyen T, Fan T, Kariyawasam AP, Liu Y, Osmond DH, George SR, O'Dowd BF (2000). "Characterization of apelin, the ligand for the APJ receptor". J. Neurochem. 74 (1): 34–41. doi:10.1046/j.1471-4159.2000.0740034.x. PMID 10617103. 
  3. ^ a b Szokodi I, Tavi P, Földes G, Voutilainen-Myllylä S, Ilves M, Tokola H, Pikkarainen S, Piuhola J, Rysä J, Tóth M, Ruskoaho H (2002). "Apelin, the novel endogenous ligand of the orphan receptor APJ, regulates cardiac contractility". Circ. Res. 91 (5): 434–40. doi:10.1161/01.RES.0000033522.37861.69. PMID 12215493. 
  4. ^ Kleinz MJ, Davenport AP (2005). "Emerging roles of apelin in biology and medicine". Pharmacol. Ther. 107 (2): 198–211. doi:10.1016/j.pharmthera.2005.04.001. PMID 15907343. 
  5. ^ O'Dowd BF, Heiber M, Chan A, Heng HH, Tsui LC, Kennedy JL, Shi X, Petronis A, George SR, Nguyen T (December 1993). "A human gene that shows identity with the gene encoding the angiotensin receptor is located on chromosome 11". Gene 136 (1–2): 355–60. doi:10.1016/0378-1119(93)90495-O. PMID 8294032. 
  6. ^ Devic E, Paquereau L, Vernier P, Knibiehler B, Audigier Y (October 1996). "Expression of a new G protein-coupled receptor X-msr is associated with an endothelial lineage in Xenopus laevis". Mech. Dev. 59 (2): 129–40. doi:10.1016/0925-4773(96)00585-0. PMID 8951791. 
  7. ^ Audigier Y (2006-04-07). "Apelin Receptor". UCSD-Nature Molecule Pages. Nature Publishing Group. doi:10.1038/mp.a000304.01. Retrieved 2009-09-02. 
  8. ^ Mesmin C, Dubois M, Becher F, Fenaille F, Ezan E (2010). "Liquid chromatography/tandem mass spectrometry assay for the absolute quantification of the expected circulating apelin peptides in human plasma". Rapid Commun Mass Spectrom 24 (19): 2875–84. doi:10.1002/rcm.4718. PMID 20857448. 
  9. ^ Mesmin C, Fenaille F, Becher F, Tabet JC, Ezan E (2011). "Identification and characterization of apelin peptides in bovine colostrum and milk by liquid chromatography-mass spectrometry.". J Proteome Res 10 (11): 5222–31. doi:10.1021/pr200725x. PMID 21939284. 
  10. ^ a b Devic E, Rizzoti K, Bodin S, Knibiehler B, Audigier Y (June 1999). "Amino acid sequence and embryonic expression of msr/apj, the mouse homolog of Xenopus X-msr and human APJ". Mech. Dev. 84 (1–2): 199–203. doi:10.1016/S0925-4773(99)00081-7. PMID 10473142. 
  11. ^ a b c Saint-Geniez M, Masri B, Malecaze F, Knibiehler B, Audigier Y (January 2002). "Expression of the murine msr/apj receptor and its ligand apelin is upregulated during formation of the retinal vessels". Mech. Dev. 110 (1–2): 183–6. doi:10.1016/S0925-4773(01)00558-5. PMID 11744380. 
  12. ^ a b Masri B, Morin N, Cornu M, Knibiehler B, Audigier Y (December 2004). "Apelin (65-77) activates p70 S6 kinase and is mitogenic for umbilical endothelial cells". FASEB J. 18 (15): 1909–11. doi:10.1096/fj.04-1930fje. PMID 15385434. 
  13. ^ a b Kasai A, Shintani N, Oda M, Kakuda M, Hashimoto H, Matsuda T, Hinuma S, Baba A (December 2004). "Apelin is a novel angiogenic factor in retinal endothelial cells". Biochem. Biophys. Res. Commun. 325 (2): 395–400. doi:10.1016/j.bbrc.2004.10.042. PMID 15530405. 
  14. ^ Cox CM, D'Agostino SL, Miller MK, Heimark RL, Krieg PA (August 2006). "Apelin, the ligand for the endothelial G-protein-coupled receptor, APJ, is a potent angiogenic factor required for normal vascular development of the frog embryo". Dev. Biol. 296 (1): 177–89. doi:10.1016/j.ydbio.2006.04.452. PMID 16750822. 
  15. ^ Tatemoto K, Takayama K, Zou MX, Kumaki I, Zhang W, Kumano K, Fujimiya M (June 2001). "The novel peptide apelin lowers blood pressure via a nitric oxide-dependent mechanism". Regul. Pept. 99 (2–3): 87–92. doi:10.1016/S0167-0115(01)00236-1. PMID 11384769. 
  16. ^ Ishida J, Hashimoto T, Hashimoto Y, Nishiwaki S, Iguchi T, Harada S, Sugaya T, Matsuzaki H, Yamamoto R, Shiota N, Okunishi H, Kihara M, Umemura S, Sugiyama F, Yagami K, Kasuya Y, Mochizuki N, Fukamizu A (June 2004). "Regulatory roles for APJ, a seven-transmembrane receptor related to angiotensin-type 1 receptor in blood pressure in vivo". J. Biol. Chem. 279 (25): 26274–9. doi:10.1074/jbc.M404149200. PMID 15087458. 
  17. ^ Masri B, Lahlou H, Mazarguil H, Knibiehler B, Audigier Y (January 2002). "Apelin (65-77) activates extracellular signal-regulated kinases via a PTX-sensitive G protein". Biochem. Biophys. Res. Commun. 290 (1): 539–45. doi:10.1006/bbrc.2001.6230. PMID 11779205. 
  18. ^ Kasai A, Shintani N, Kato H, Matsuda S, Gomi F, Haba R, Hashimoto H, Kakuda M, Tano Y, Baba A (October 2008). "Retardation of retinal vascular development in apelin-deficient mice". Arterioscler. Thromb. Vasc. Biol. 28 (10): 1717–22. doi:10.1161/ATVBAHA.108.163402. PMID 18599802. 
  19. ^ Scott IC, Masri B, D'Amico LA, Jin SW, Jungblut B, Wehman AM, Baier H, Audigier Y, Stainier DY (March 2007). "The g protein-coupled receptor agtrl1b regulates early development of myocardial progenitors". Dev. Cell 12 (3): 403–13. doi:10.1016/j.devcel.2007.01.012. PMID 17336906. 
  20. ^ Zeng XX, Wilm TP, Sepich DS, Solnica-Krezel L (March 2007). "Apelin and its receptor control heart field formation during zebrafish gastrulation". Dev. Cell 12 (3): 391–402. doi:10.1016/j.devcel.2007.01.011. PMID 17336905. 
  21. ^ Berry MF, Pirolli TJ, Jayasankar V, Burdick J, Morine KJ, Gardner TJ, Woo YJ (September 2004). "Apelin has in vivo inotropic effects on normal and failing hearts". Circulation 110 (11 Suppl 1): II187–93. doi:10.1161/01.CIR.0000138382.57325.5c. PMID 15364861. 
  22. ^ Ashley EA, Powers J, Chen M, Kundu R, Finsterbach T, Caffarelli A, Deng A, Eichhorn J, Mahajan R, Agrawal R, Greve J, Robbins R, Patterson AJ, Bernstein D, Quertermous T (January 2005). "The endogenous peptide apelin potently improves cardiac contractility and reduces cardiac loading in vivo". Cardiovasc. Res. 65 (1): 73–82. doi:10.1016/j.cardiores.2004.08.018. PMC 2517138. PMID 15621035. 
  23. ^ Kuba K, Zhang L, Imai Y, Arab S, Chen M, Maekawa Y, Leschnik M, Leibbrandt A, Markovic M, Makovic M, Schwaighofer J, Beetz N, Musialek R, Neely GG, Komnenovic V, Kolm U, Metzler B, Ricci R, Hara H, Meixner A, Nghiem M, Chen X, Dawood F, Wong KM, Sarao R, Cukerman E, Kimura A, Hein L, Thalhammer J, Liu PP, Penninger JM (August 2007). "Impaired heart contractility in Apelin gene-deficient mice associated with aging and pressure overload". Circ. Res. 101 (4): e32–42. doi:10.1161/CIRCRESAHA.107.158659. PMID 17673668. 
  24. ^ Principe A, Melgar-Lesmes P, Fernández-Varo G, Del Arbol LR, Ros J, Morales-Ruiz M, Bernardi M, Arroyo V, Jiménez W (2008). "The hepatic apelin system: A new therapeutic target for liver disease". Hepatology 48 (4): 1193–1201. doi:10.1002/hep.22467. PMID 18816630. 
  25. ^ O'Carroll AM, Selby TL, Palkovits M, Lolait SJ (June 2000). "Distribution of mRNA encoding B78/apj, the rat homologue of the human APJ receptor, and its endogenous ligand apelin in brain and peripheral tissues". Biochim. Biophys. Acta 1492 (1): 72–80. doi:10.1016/S0167-4781(00)00072-5. PMID 11004481. 
  26. ^ De Mota et al., 2000
  27. ^ De Mota N, Lenkei Z, Llorens-Cortès C (December 2000). "Cloning, pharmacological characterization and brain distribution of the rat apelin receptor". Neuroendocrinology 72 (6): 400–7. doi:10.1159/000054609. PMID 11146423. 
  28. ^ Taheri S, Murphy K, Cohen M, Sujkovic E, Kennedy A, Dhillo W, Dakin C, Sajedi A, Ghatei M, Bloom S (March 2002). "The effects of centrally administered apelin-13 on food intake, water intake and pituitary hormone release in rats". Biochem. Biophys. Res. Commun. 291 (5): 1208–12. doi:10.1006/bbrc.2002.6575. PMID 11883945. 
  29. ^ Sunter D, Hewson AK, Dickson SL (December 2003). "Intracerebroventricular injection of apelin-13 reduces food intake in the rat". Neurosci. Lett. 353 (1): 1–4. doi:10.1016/S0304-3940(03)00351-3. PMID 14642423. 
  30. ^ O'Shea M, Hansen MJ, Tatemoto K, Morris MJ (June 2003). "Inhibitory effect of apelin-12 on nocturnal food intake in the rat". Nutr Neurosci 6 (3): 163–7. doi:10.1080/1028415031000111273. PMID 12793520. 
  31. ^ Wang G, Anini Y, Wei W, Qi X, OCarroll AM, Mochizuki T, Wang HQ, Hellmich MR, Englander EW, Greeley GH (March 2004). "Apelin, a new enteric peptide: localization in the gastrointestinal tract, ontogeny, and stimulation of gastric cell proliferation and of cholecystokinin secretion". Endocrinology 145 (3): 1342–8. doi:10.1210/en.2003-1116. PMID 14670994. 
  32. ^ a b Lambrecht NW, Yakubov I, Zer C, Sachs G (March 2006). "Transcriptomes of purified gastric ECL and parietal cells: identification of a novel pathway regulating acid secretion". Physiol. Genomics 25 (1): 153–65. doi:10.1152/physiolgenomics.00271.2005. PMID 16403840. 
  33. ^ Sorhede Winzell et al., 2005
  34. ^ Wang G, Kundu R, Han S, Qi X, Englander EW, Quertermous T, Greeley GH (August 2009). "Ontogeny of apelin and its receptor in the rodent gastrointestinal tract". Regul. Pept. 158 (1–3): 32–9. doi:10.1016/j.regpep.2009.07.016. PMC 2761510. PMID 19660504. 
  35. ^ Sörhede Winzell M, Magnusson C, Ahrén B (November 2005). "The apj receptor is expressed in pancreatic islets and its ligand, apelin, inhibits insulin secretion in mice". Regul. Pept. 131 (1–3): 12–7. doi:10.1016/j.regpep.2005.05.004. PMID 15970338. 
  36. ^ Boucher J, Masri B, Daviaud D, Gesta S, Guigné C, Mazzucotelli A, Castan-Laurell I, Tack I, Knibiehler B, Carpéné C, Audigier Y, Saulnier-Blache JS, Valet P (April 2005). "Apelin, a newly identified adipokine up-regulated by insulin and obesity". Endocrinology 146 (4): 1764–71. doi:10.1210/en.2004-1427. PMID 15677759. 
  37. ^ Dray C, Knauf C, Daviaud D, Waget A, Boucher J, Buléon M, Cani PD, Attané C, Guigné C, Carpéné C, Burcelin R, Castan-Laurell I, Valet P (November 2008). "Apelin stimulates glucose utilization in normal and obese insulin-resistant mice". Cell Metab. 8 (5): 437–45. doi:10.1016/j.cmet.2008.10.003. PMID 19046574. 
  38. ^ Xie H, Tang SY, Cui RR, Huang J, Ren XH, Yuan LQ, Lu Y, Yang M, Zhou HD, Wu XP, Luo XH, Liao EY (May 2006). "Apelin and its receptor are expressed in human osteoblasts". Regul. Pept. 134 (2–3): 118–25. doi:10.1016/j.regpep.2006.02.004. PMID 16563531. 

Further reading[edit]

  • Lee DK, George SR, O'Dowd BF (2006). "Unravelling the roles of the apelin system: prospective therapeutic applications in heart failure and obesity". Trends Pharmacol. Sci. 27 (4): 190–4. doi:10.1016/j.tips.2006.02.006. PMID 16530855. 
  • Lee DK, Saldivia VR, Nguyen T, Cheng R, George SR, O'Dowd BF (2005). "Modification of the terminal residue of apelin-13 antagonizes its hypotensive action". Endocrinology 146 (1): 231–6. doi:10.1210/en.2004-0359. PMID 15486224. 
  • Lee DK, Lança AJ, Cheng R, Nguyen T, Ji XD, Gobeil F, Chemtob S, George SR, O'Dowd BF (2004). "Agonist-independent nuclear localization of the Apelin, angiotensin AT1, and bradykinin B2 receptors". J. Biol. Chem. 279 (9): 7901–8. doi:10.1074/jbc.M306377200. PMID 14645236. 
  • O'Dowd BF, Heiber M, Chan A, Heng HH, Tsui LC, Kennedy JL, Shi X, Petronis A, George SR, Nguyen T (1993). "A human gene that shows identity with the gene encoding the angiotensin receptor is located on chromosome 11". Gene 136 (1–2): 355–60. doi:10.1016/0378-1119(93)90495-O. PMID 8294032. 

External links[edit]