Biology:Urocortin III

From HandWiki
Short description: Amino acid peptide

Urocortin III, a 38–41 amino acid peptide, is a member of the CRF (corticotropin-releasing factor), also known as CRH (corticotropin-releasing hormone)[1] family of peptides, with a long evolutionary lineage.[2][3]

Separate chromosomes harboring two exons each are home to the genes encoding UCN, UCN2, and UCN3.[4] A gene on human chromosome 10p15 at location 5.40 Mb encodes the urocortin, UCN III, which has been discovered more recently. A 161 amino acid precursor is produced when the UCN III gene is translated.[5] Mature UCN III with 38 or 41 amino acids would be produced by proteolytic cleavage between arginine- or threonine-lysine residues. Human plasma contains both the 38 and 41 amino acid forms of UCN III, although the 38 amino acid form is more prevalent, according to findings from high-performance liquid chromatography.[2]

Each urocortin peptide has a distinct expression location and function, yet they all share conserved structural similarity.[4] Urocortins' structures, as determined by nuclear magnetic resonance, exhibit alpha-helical secondary structures, which support biological activity and binding selectivity.[6]

Evolutionary view

Multiple urocortin genes are present in vertebrate lineages as a result of the two waves of vertebrate whole-genome duplication.[7] Two ligands, the CRF/UCN1 and UCN2/UCN3 paralogs, and two receptors, CRFR1 and CRFR2, were produced by a first genome duplication in early vertebrates.[8][9] The CRF system observed in modern vertebrates, which has four ligands and two receptors, was then created by a second genome duplication that split the gene between UCN2 and UCN3 and between CRF and UCN1.[10] Two peptide genes were hypothesized to have been present in a vertebrate progenitor that gave rise to the different lineages that contained urocortin (UCN I), CRH1, and CRH2 in one group and urocortin II (UCN II) and urocortin III (UCN III ) in the other.[7]

In many vertebrates, there are five members of the corticotropin-releasing hormone and urocortin family of peptides: CRH (crha/crhb in teleosts), CRH2, UCN/UTS1, UCN II, and UCN III.[11] The two receptors, CRFR1 and CRFR2, and the four ligands, CRF, Urocortin1 (UCN1), UCN2, and UCN3, make up the mammalian CRF system.[12] Genes for mentioned proteins can perform a multitude of tasks in a wide range of animals due to differences in their expression patterns and receptor affinities.[11]

Urocortin affinity to receptors

Compared to UCN II or UCN III , UCN I has a greater binding affinity for the CRHR1 receptor.[6] Urocortin III is extremely selective for the CRF2 receptor, in contrast to Urocortin I and comparable to Urocortin II.[5] Of the two closely related CRF receptors (CRFR1 and CRFR2) that are members of the class B family of G protein-coupled receptors, each peptide activates at least one of them.[13] CRFR2 can be effectively activated by UCN II and UCN III.[2][14] By attaching itself to CRHR2 with a strong affinity, this peptide (UCNIII) helps regulate a number of bodily processes.[15] All things considered, UCNs have approximately ten times more affinity for CRHR2 than CRH.[16]

Distribution

UCN III is widely distributed throughout the brain and is present in many bodily tissues—including the skin, gastrointestinal tract (GI tract), pancreatic beta cells, kidneys, heart, endocrine system, and brain.[11][15] The medial amygdala (MeA), rostral perifornical area of the hypothalamus, bed nucleus of the stria terminalis (BNST), superior paraolivary nucleus, nucleus parabrachialis, and premammillary nucleus are the primary locations where UCN III is expressed.[5][17]

Expression of UCN III occurs late in the differentiation process of beta cells, where it is necessary for complete insulin secretion triggered by glucose and incretin, and is shown in mature beta cells in both mice and humans.[13][18] Beta cells use the ATP-sensitive potassium channel (KATP channel) to facilitate the glucose-dependent release of UCN III.[18] This is corroborated by the expression of PC1/3, Nkx6.1, and Pdx1 in hESC-derived UCN III + beta cells. But human UCN III is not specific to the beta cell lineage; rather, it is a generic marker for both the alpha and beta cell lineages, as seen by its expression in primary and hESC-derived alpha cells.[13][19] A universal marker of alpha and beta cell development in humans is Ucn III.[19]

After triggering the receptors in the cerebral endothelial cells, UCN III crosses the blood–brain barrier, as demonstrated by a transneuronal tracer injection into the ventral pre-mammillary nucleus of the rat brain.[20] Further research using tracer molecule injections to examine the function of UCN III reveals that UCN III is located rostral to the hypothalamus and projects to the ventromedial hypothalamus. It is well recognized that this brain region controls energy balance and hunger. In the same brain regions, UCN III and CRHR2 are expressed, and different physiological and behavioral processes result from their activation.[21][22]

Stress

One important neuropeptide that modulates various aspects of behavior and brain function is UCN III. In the brain, UCN III mRNA was specifically detected in the perifornical region, the medial nucleus of the amygdala, and the median preoptic nucleus.[23][20][24][17]

The endocrine, autonomic, and behavioral reactions to stress are all regulated by the corticotropin-releasing factor (CRF) system, which is widely recognized for this function.[25] When stress levels are elevated, UCN III expression increases. UCN III is mostly expressed in areas linked to stress-related behaviors.[26]

The origin of projection to the midbrain's median amygdala region is the ventral pre-mammillary nucleus, which exhibited high UCN III positivity.[16][23][27] The confirmation of UCN III 's essential role in numerous brain activities linked to anxiety, such as aggression and sexual behaviors, comes from its engagement in this circuit.[28][29] Mammalian stress reactions are known to be modulated by urocortins. It alters mammals' reactions to stress and functions in the stress recovery mechanism. UCN III and its receptor's function in clinical disorders linked to stress,[15]

Stress homeostasis is known to be mediated via a regulatory axis that includes the neuropeptide urocortin III (UCN III ) and the corticotropin-releasing hormone receptor 2 (CRHR2). Cardiovascular disease, sleep apnea, post-traumatic stress disorder, and other stress-related health issues are thought to be associated with dysregulation of this peptide/receptor axis. To develop a workable clinical laboratory diagnostic, it is crucial to comprehend the physiology and measurement of the UCN III /CRHR2 axis.[15]

References

  1. ↑ "The Corticotropin-Releasing Factor Family: Physiology of the Stress Response". Physiological Reviews 98 (4): 2225–2286. October 2018. doi:10.1152/physrev.00042.2017. PMID 30109816. 
  2. ↑ 2.0 2.1 2.2 "Human stresscopin and stresscopin-related peptide are selective ligands for the type 2 corticotropin-releasing hormone receptor". Nature Medicine 7 (5): 605–611. May 2001. doi:10.1038/87936. PMID 11329063. 
  3. ↑ "Chapter 183 - Urocortins". Handbook of Biologically Active Peptides (Second ed.). Boston: Academic Press. January 2013. pp. 1346–1353. doi:10.1016/b978-0-12-385095-9.00183-4. ISBN 978-0-12-385095-9. 
  4. ↑ 4.0 4.1 "Urocortins in the mammalian endocrine system". Acta Veterinaria Scandinavica 61 (1): 46. October 2019. doi:10.1186/s13028-019-0480-2. PMID 31585551. 
  5. ↑ 5.0 5.1 5.2 "Identification of urocortin III, an additional member of the corticotropin-releasing factor (CRF) family with high affinity for the CRF2 receptor". Proceedings of the National Academy of Sciences of the United States of America 98 (13): 7570–7575. June 2001. doi:10.1073/pnas.121165198. PMID 11416224. Bibcode: 2001PNAS...98.7570L. 
  6. ↑ 6.0 6.1 "Common and divergent structural features of a series of corticotropin releasing factor-related peptides". Journal of the American Chemical Society 129 (51): 16102–16114. December 2007. doi:10.1021/ja0760933. PMID 18052377. 
  7. ↑ 7.0 7.1 "CRF and CRF receptors: role in stress responsivity and other behaviors". Annual Review of Pharmacology and Toxicology 44 (1): 525–557. 2004-02-10. doi:10.1146/annurev.pharmtox.44.101802.121410. PMID 14744257. 
  8. ↑ "Urocortins: emerging metabolic and energy homeostasis perspectives". Trends in Endocrinology and Metabolism 19 (4): 122–129. May 2008. doi:10.1016/j.tem.2007.12.002. PMID 18337115. 
  9. ↑ "The corticotropin-releasing factor family of peptides and CRF receptors: their roles in the regulation of energy balance". European Journal of Pharmacology. The pharmacotherapy of obesity 440 (2–3): 189–197. April 2002. doi:10.1016/S0014-2999(02)01428-0. PMID 12007535. 
  10. ↑ "Structural and functional evolution of vertebrate neuroendocrine stress systems". Annals of the New York Academy of Sciences 1163 (1): 1–16. April 2009. doi:10.1111/j.1749-6632.2009.04433.x. PMID 19456324. Bibcode: 2009NYASA1163....1D. 
  11. ↑ 11.0 11.1 11.2 "Expression patterns and evolution of urocortin and corticotropin-releasing hormone genes in a cichlid fish". The Journal of Comparative Neurology 529 (10): 2596–2619. July 2021. doi:10.1002/cne.25113. PMID 33474732. 
  12. ↑ "The CRF Family of Neuropeptides and their Receptors - Mediators of the Central Stress Response". Current Molecular Pharmacology 11 (1): 4–31. 2018. doi:10.2174/1874467210666170302104053. PMID 28260504. 
  13. ↑ 13.0 13.1 13.2 "Urocortin III is expressed in pancreatic beta-cells and stimulates insulin and glucagon secretion". Endocrinology 144 (7): 3216–3224. July 2003. doi:10.1210/en.2002-0087. PMID 12810578. 
  14. ↑ "Urocortin II: a member of the corticotropin-releasing factor (CRF) neuropeptide family that is selectively bound by type 2 CRF receptors". Proceedings of the National Academy of Sciences of the United States of America 98 (5): 2843–2848. February 2001. doi:10.1073/pnas.051626398. PMID 11226328. Bibcode: 2001PNAS...98.2843R. 
  15. ↑ 15.0 15.1 15.2 15.3 "The urocortin peptides: biological relevance and laboratory aspects of UCN3 and its receptor". Critical Reviews in Clinical Laboratory Sciences 59 (8): 573–585. December 2022. doi:10.1080/10408363.2022.2080175. PMID 35738909. 
  16. ↑ 16.0 16.1 "Urocortin, a mammalian neuropeptide related to fish urotensin I and to corticotropin-releasing factor". Nature 378 (6554): 287–292. November 1995. doi:10.1038/378287a0. PMID 7477349. Bibcode: 1995Natur.378..287V. 
  17. ↑ 17.0 17.1 "Urocortin 3 modulates social discrimination abilities via corticotropin-releasing hormone receptor type 2". The Journal of Neuroscience 30 (27): 9103–9116. July 2010. doi:10.1523/JNEUROSCI.1049-10.2010. PMID 20610744. 
  18. ↑ 18.0 18.1 "Urocortin 3 regulates glucose-stimulated insulin secretion and energy homeostasis". Proceedings of the National Academy of Sciences of the United States of America 104 (10): 4206–4211. March 2007. doi:10.1073/pnas.0611641104. PMID 17360501. Bibcode: 2007PNAS..104.4206L. 
  19. ↑ 19.0 19.1 "Urocortin 3 marks mature human primary and embryonic stem cell-derived pancreatic alpha and beta cells". PLOS ONE 7 (12): e52181. 2012-12-14. doi:10.1371/journal.pone.0052181. PMID 23251699. Bibcode: 2012PLoSO...752181V. 
  20. ↑ 20.0 20.1 "Urocortin and the brain". Progress in Neurobiology 84 (2): 148–156. February 2008. doi:10.1016/j.pneurobio.2007.10.008. PMID 18078706. 
  21. ↑ "Localization of novel corticotropin-releasing factor receptor (CRF2) mRNA expression to specific subcortical nuclei in rat brain: comparison with CRF1 receptor mRNA expression". The Journal of Neuroscience 15 (10): 6340–6350. October 1995. doi:10.1523/JNEUROSCI.15-10-06340.1995. PMID 7472399. 
  22. ↑ "Distribution of mRNAs encoding CRF receptors in brain and pituitary of rat and mouse". The Journal of Comparative Neurology 428 (2): 191–212. December 2000. doi:10.1002/1096-9861(20001211)428:2<191::AID-CNE1>3.0.CO;2-U. PMID 11064361. 
  23. ↑ 23.0 23.1 "Urocortin III-immunoreactive projections in rat brain: partial overlap with sites of type 2 corticotrophin-releasing factor receptor expression". The Journal of Neuroscience 22 (3): 991–1001. February 2002. doi:10.1523/JNEUROSCI.22-03-00991.2002. PMID 11826127. 
  24. ↑ "Distribution and axonal projections of neurons coexpressing thyrotropin-releasing hormone and urocortin 3 in the rat brain". The Journal of Comparative Neurology 517 (6): 825–840. December 2009. doi:10.1002/cne.22180. PMID 19844978. 
  25. ↑ "Urocortins and their unfolding role in mammalian social behavior". Cell and Tissue Research 375 (1): 133–142. January 2019. doi:10.1007/s00441-018-2962-3. PMID 30465153. 
  26. ↑ "Urocortin III, a brain neuropeptide of the corticotropin-releasing hormone family: modulation by stress and attenuation of some anxiety-like behaviours". Journal of Neuroendocrinology 16 (5): 411–422. May 2004. doi:10.1111/j.1365-2826.2004.01170.x. PMID 15117334. 
  27. ↑ "Identification of urocortin 3 afferent projection to the ventromedial nucleus of the hypothalamus in rat brain". The Journal of Comparative Neurology 519 (10): 2023–2042. July 2011. doi:10.1002/cne.22620. PMID 21452217. 
  28. ↑ "A role for corticotropin releasing factor and urocortin in behavioral responses to stressors". Brain Research 848 (1–2): 141–152. November 1999. doi:10.1016/S0006-8993(99)01991-5. PMID 10612706. 
  29. ↑ "Central urocortin activation of sympathetic-regulated energy metabolism in Wistar rats". Brain Research 930 (1–2): 37–41. March 2002. doi:10.1016/S0006-8993(01)03401-1. PMID 11879793. 



Retrieved from "https://handwiki.org/wiki/index.php?title=Biology:Urocortin_III&oldid=3605994"