Have you ever heard of eternal organisms?
Jellyfish (Turritopsis dohrnii), Hydra, and lobsters have one thing in common: it turns out that they never age thanks to a never-ending enzyme supply.
Nature is a surprising source of beauty, and thereby, some organisms, as well as germinal stem and cancer cells, never grow old. Why? Well, as Albert Einstein once said: “Look deep into nature, and then you will understand everything better”.
A new important finding has come to light in recent years: its name is telomerase and due to its crucial role in telomeres regeneration, some scientists call it “the enzyme of the eternal youth” [2]. Telomeres are protective DNA–protein structures at the ends of the linear chromosomes that safeguard chromosome integrity and genomic stability during cell division. Unfortunately, a small portion of telomeric DNA is lost during each cell division along with cell proliferative ability, unless telomerase, the enzyme responsible for adding DNA repeats (5′-TTAGGG-3′) to our chromosome ends, is expressed.
Fig. Illustration showing the position of telomeres at the end of our chromosomes [10].
Telomerase is active in fetal cells, but soon after birth, most somatic cells stop producing telomerase, thus our “life clock” starts: at each cell division telomeres shorten substantially, from 15,000 bp in young cells to the critical length of 8,000 bp, which defines the end of cell replicative abilities and the beginning of the decline [2]. Therefore, it is not surprising that telomere shorting is tightly associated with the aging process and age-related diseases. Accordingly, growing evidence suggests that accelerated telomere shortening might contribute to different diseases (e.g. dyskeratosis congenital, aplastic anemia, and idiopathic pulmonary fibrosis) characterized by premature aging and increased organ failure, whereas telomerase re-activation represents a promising strategy to restore telomere length and counteract neurodegenerative diseases (e.g. Alzheimer's disease, Parkinson's disease, Huntington's diseases) [9].
Could our behavior influence telomerase activity and the aging process?
“The more chronic stress you are under, the shorter your telomeres” [7] states Elizabeth Blackburn the discoverer of the telomerase. She points out that our attitude matters! Your lifestyle and the way you respond to unexpected events can be a measuring unit of your telomeres’ length; therefore, some disorders due to poor stress management, such as bipolar disorder, are associated with both accelerated aging and telomers’ shortening [1]. Nevertheless, we know that people who practice meditation techniques improve the maintenance of telomeres length. In this respect, can we affirm that we have control over the way we age? How else could we increase our telomere length to counteract aging? If the telomerase activity is low, it might be interesting to know about the Astragalus membranaceous plant, which extracts or root is sold in the market nowadays as a nutraceutical activator of the telomerase [3]: however, it is a controversial topic, due to the absence of information about the efficiency of this drug and accordingly, lawsuits have arisen challenging anti-aging and safety claims [5].
Indeed, most cancer cells exploit telomerase to achieve “immortality” and the replicative behavior supporting their aberrant and destructive growth [4]. Therefore, an indiscriminate increase in telomerase activity could heighten the risk of cancer development. Until we find new answers to these unknowns, we won’t be sure how far the consequences of these products will reach. However, we can feel proud of such findings and the fact that several diseases with no treatment nowadays could be targeted in the years to come, leading to a better quality of life and counteracting early aging or even death. Up to now, we have always believed that senescence is a natural process in human beings, but there must be more knowledge to be elucidated; what if we could revert the aging process as the jellyfish do?
References
[1] Barbé-Tuana, F. M., Parisi, M. M., Panizzutti, B. S., Fries, G. R., Grun, L. K., Guma, F. T., Kapczinski, F., Berk, M., Gama, C. S., & Rosa, A. R. (2016). Shortened telomere length in bipolar disorder: a comparison of the early and late stages of disease. Revista Brasileira de Psiquiatria, 38(4), 281–286. https://doi.org/10.1590/1516-4446-2016-1910
[2] Fossel, M. (2017). La enzima de la eterna juventud [E-book]. Diana. https://www.amazon.it/dp/6070738004/ref=cm_sw_r_wa_apa_fabt1_lp9WFb80VGTFP
[3] Guinobert, I., Blondeau, C., Colicchio, B., Oudrhiri, N., Dieterlen, A., Jeandidier, E., Deschenes, G., Bardot, V., Cotte, C., Ripoche, I., Carde, P., Berthomier, L., & M’Kacher, R. (2020). The Use of Natural Agents to Counteract Telomere Shortening: Effects of a Multi-Component Extract of Astragalus mongholicus Bunge and Danazol. Biomedicines, 8(2), 31. https://doi.org/10.3390/biomedicines8020031
[4] Ivancich, M., Schrank, Z., Wojdyla, L., Leviskas, B., Kuckovic, A., Sanjali, A., & Puri, N. (2017). Treating Cancer by Targeting Telomeres and Telomerase. Antioxidants, 6(1), 15. https://doi.org/10.3390/antiox6010015
[5] Jaskelioff, M., Jesus, B. B., & Harley, C. B. (2012, July 31). Lawsuit challenges anti-ageing claims. Nature News & Comment. https://www.nature.com/news/lawsuit-challenges-anti-ageing-claims-1.11090
Date accessed: 27 Nov. 2020
[6] McMillan, F. (2018, April 30). Researchers Have Discovered What The “Immortality” Enzyme Looks Like. Forbes. https://www.forbes.com/sites/fionamcmillan/2018/04/28/researchers-have-discovered-what-the-immortality-enzyme-looks-like/?sh=4736b05e2423
Date accessed: 27 Nov. 2020
[7] TED. (2017, December 15). The science of cells that never get old | Elizabeth Blackburn. YouTube. https://www.youtube.com/watch?v=2wseM6wWd74&feature=emb_title
Date accessed: 27 Nov. 2020
[8] The Jackson Laboratory. (2020, August 24). What are telomeres? | Telomere animation. YouTube. https://www.youtube.com/watch?v=U0fRAr-ZHCo
Date accessed: 27 Nov. 2020
[9] Wang, J., Liu, Y., Xia, Q., Xia, Q., Wang, B., Yang, C., Liang, J., & Liu, X. (2020). Potential roles of telomeres and telomerase in neurodegenerative diseases. International Journal of Biological Macromolecules, 163, 1060–1078. https://doi.org/10.1016/j.ijbiomac.2020.07.046
To find out more information about telomeres, look at this resource:
[10] What is a telomere? (2016, January 25). Yourgenome. https://www.yourgenome.org/facts/what-is-a-telomere
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