Biology:Adropin
Adropin is a peptide encoded by the energy homeostasis-associated gene ENHO,[1] which is highly conserved across mammals.[2]
Adropin's biological role was first described in mice by a group led by Andrew Butler, as a protein hormone, secreted from the liver (hepatokine), in the context of obesity and energy homeostasis. They derived the name "Adropin" from the Latin "aduro" - to set fire to, and "pinguis" - fat.[3] The hormone adropin is produced in places like the liver and brain, as well as peripheral tissues in the heart and gastrointestinal tract.[4]
In animals, adropin has been shown to have a regulatory role in carbohydrate/lipid metabolism,[5] as well as in endothelial function.[6][7] Adropin expression in the liver is regulated by feeding status and macronutrient content,[5] as well as by the biological clock.[8] Liver adropin is upregulated by estrogen[9] via ERa.[10]
In humans, lower levels of circulating adropin are associated with several medical conditions including metabolic syndrome, obesity[11] and inflammatory bowel disease.[12]
The brain is the organ with the highest levels of adropin expression.[13] In the brain, adropin has been shown to have a potential protective role role against neurological disease,[14] including in the context of brain aging and cognitive function,[15][16] as well as following acute ischemia.[17]
The orphan G protein-coupled receptor GPR19, has been proposed as a receptor for adropin.[18][19]
In the mouse ovary, adropin and GPR19 are strongly detected in the granulosa cells of large antral follicles and corpus luteum.[20] An additional study suggests a role for adropin in the acceleration of pubertal development.[21]
Structure and Synthesis
Adropin is a small protein composed of 76 amino acids, and it is produced primarily in the liver and the brain. The precursor of adropin is a larger protein called Energy Homeostasis-Associated (ENHO), and adropin is released through the cleavage of ENHO.[1]
Receptors and targets
The specific receptors for adropin are not yet fully elucidated, and this is an area of active research. However, studies suggest that adropin might exert its effects by interacting with certain cell surface receptors.[22]
Metabolic
One of the primary areas of interest regarding adropin is its role in metabolic regulation. Research indicates that adropin may play a crucial role in glucose and lipid metabolism. It has been associated with insulin sensitivity, suggesting a potential role in the regulation of blood sugar levels.[23]
In animal studies, alterations in adropin levels have been linked to changes in energy expenditure and body weight. For example, some studies have shown that mice with elevated adropin levels tend to be more resistant to diet-induced obesity.[24]
Cardiovascular effects
Adropin also appears to have cardiovascular effects. It has been implicated in the regulation of endothelial function, which is essential for maintaining blood vessel health. Dysfunction in endothelial cells can contribute to conditions such as atherosclerosis and hypertension. Some studies suggest that adropin may have a protective role in cardiovascular health by promoting the dilation of blood vessels and reducing oxidative stress.[25]
Brain function
Adropin is produced in the brain, particularly in the hypothalamus.[4] The hypothalamus is a crucial region for the regulation of various physiological processes, including metabolism and energy balance. The presence of adropin in the brain suggests that it may have additional roles in the central nervous system, although the specifics are still being explored.
Circadian rhythm
There is evidence to suggest that adropin levels exhibit a circadian rhythm, meaning they follow a natural 24-hour cycle.[26] Circadian rhythms play a vital role in regulating various physiological processes, including sleep-wake cycles, hormone secretion, and metabolism.
Clinical Implications
Given its involvement in metabolic and cardiovascular processes, adropin has sparked interest as a potential therapeutic target for conditions such as obesity, diabetes, and cardiovascular disease. However, much more research is needed to understand the precise mechanisms of adropin action and its potential applications in clinical settings.
References
- ↑ 1.0 1.1 "ENHO Gene - GeneCards | ENHO Protein | ENHO Antibody". https://www.genecards.org/cgi-bin/carddisp.pl?gene=ENHO.
- ↑ "ortholog_gene_375704[group - Gene - NCBI"]. https://www.ncbi.nlm.nih.gov/gene/?Term=ortholog_gene_375704%5Bgroup%5D.
- ↑ "Identification of adropin as a secreted factor linking dietary macronutrient intake with energy homeostasis and lipid metabolism" (in English). Cell Metabolism 8 (6): 468–481. December 2008. doi:10.1016/j.cmet.2008.10.011. PMID 19041763.
- ↑ 4.0 4.1 "Adropin as A Fat-Burning Hormone with Multiple Functions-Review of a Decade of Research". Molecules 25 (3): 549. January 2020. doi:10.3390/molecules25030549. PMID 32012786.
- ↑ 5.0 5.1 "Hepatocyte expression of the micropeptide adropin regulates the liver fasting response and is enhanced by caloric restriction" (in English). The Journal of Biological Chemistry 295 (40): 13753–13768. October 2020. doi:10.1074/jbc.RA120.014381. PMID 32727846.
- ↑ "Adropin is a novel regulator of endothelial function". Circulation 122 (11 Suppl): S185–S192. September 2010. doi:10.1161/CIRCULATIONAHA.109.931782. PMID 20837912.
- ↑ "Role of adropin in arterial stiffening associated with obesity and type 2 diabetes". American Journal of Physiology. Heart and Circulatory Physiology 323 (5): H879–H891. November 2022. doi:10.1152/ajpheart.00385.2022. PMID 36083795.
- ↑ "Adropin as a potential mediator of the metabolic system-autonomic nervous system-chronobiology axis: Implementing a personalized signature-based platform for chronotherapy". Obesity Reviews 22 (2): e13108. February 2021. doi:10.1111/obr.13108. PMID 32720402.
- ↑ "Hepatic adropin is regulated by estrogen and contributes to adverse metabolic phenotypes in ovariectomized mice". Molecular Metabolism 60: 101482. June 2022. doi:10.1016/j.molmet.2022.101482. PMID 35364299.
- ↑ "ERα-Dependent Regulation of Adropin Predicts Sex Differences in Liver Homeostasis during High-Fat Diet". Nutrients 14 (16): 3262. August 2022. doi:10.3390/nu14163262. PMID 36014766.
- ↑ "Circulating levels of adropin and overweight/obesity: a systematic review and meta-analysis of observational studies". Hormones 21 (1): 15–22. March 2022. doi:10.1007/s42000-021-00331-0. PMID 34897581.
- ↑ "Serum adropin levels are reduced in patients with inflammatory bowel diseases". Scientific Reports 10 (1): 9264. June 2020. doi:10.1038/s41598-020-66254-9. PMID 32518265. Bibcode: 2020NatSR..10.9264B.
- ↑ "Tissue expression of ENHO - Summary - The Human Protein Atlas". https://www.proteinatlas.org/ENSG00000168913-ENHO/tissue.
- ↑ "Protective roles of adropin in neurological disease". American Journal of Physiology. Cell Physiology 324 (3): C674–C678. March 2023. doi:10.1152/ajpcell.00318.2022. PMID 36717106.
- ↑ "Adropin correlates with aging-related neuropathology in humans and improves cognitive function in aging mice". npj Aging and Mechanisms of Disease 7 (1): 23. August 2021. doi:10.1038/s41514-021-00076-5. PMID 34462439.
- ↑ "Low circulating adropin concentrations predict increased risk of cognitive decline in community-dwelling older adults". GeroScience. May 2023. doi:10.1007/s11357-023-00824-3. PMID 37233882.
- ↑ "Therapeutic Benefits of Adropin in Aged Mice After Transient Ischemic Stroke via Reduction of Blood-Brain Barrier Damage". Stroke 54 (1): 234–244. January 2023. doi:10.1161/STROKEAHA.122.039628. PMID 36305313.
- ↑ "Adropin acts in brain to inhibit water drinking: potential interaction with the orphan G protein-coupled receptor, GPR19". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 310 (6): R476–R480. March 2016. doi:10.1152/ajpregu.00511.2015. PMID 26739651.
- ↑ "Probing Adropin-Gpr19 Interactions and Signal Transduction" (in en). Journal of Pharmacology and Experimental Therapeutics 385 (S3): 430. June 2023. doi:10.1124/jpet.122.550630. ISSN 0022-3565. https://jpet.aspetjournals.org/content/385/S3/430.
- ↑ "Adropin may regulate corpus luteum formation and its function in adult mouse ovary". Hormones 22 (4): 725–739. December 2023. doi:10.1007/s42000-023-00476-0. PMID 37597158.
- ↑ "Ontogeny of adropin and its receptor expression during postnatal development and its pro-gonadal role in the ovary of pre-pubertal mouse". The Journal of Steroid Biochemistry and Molecular Biology 234: 106404. November 2023. doi:10.1016/j.jsbmb.2023.106404. PMID 37743028.
- ↑ "Adropin acts in brain to inhibit water drinking: potential interaction with the orphan G protein-coupled receptor, GPR19". American Journal of Physiology. Regulatory, Integrative and Comparative Physiology 310 (6): R476–R480. March 2016. doi:10.1152/ajpregu.00511.2015. PMID 26739651.
- ↑ "Therapeutic effects of adropin on glucose tolerance and substrate utilization in diet-induced obese mice with insulin resistance". Molecular Metabolism 4 (4): 310–324. April 2015. doi:10.1016/j.molmet.2015.01.005. PMID 25830094.
- ↑ "Adropin deficiency is associated with increased adiposity and insulin resistance". Obesity 20 (7): 1394–1402. July 2012. doi:10.1038/oby.2012.31. PMID 22318315.
- ↑ "Role of Adropin in Cardiometabolic Disorders: From Pathophysiological Mechanisms to Therapeutic Target". Biomedicines 9 (10): 1407. October 2021. doi:10.3390/biomedicines9101407. PMID 34680524.
- ↑ "Hepatocyte expression of the micropeptide adropin regulates the liver fasting response and is enhanced by caloric restriction". The Journal of Biological Chemistry 295 (40): 13753–13768. October 2020. doi:10.1074/jbc.ra120.014381. PMID 32727846.
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