Among the major questions Tara Pacific researchers are trying to answer, one has not been mentioned very much: aging. Eric Gilson, Professor of Cell Biology at the Faculty of Medicine in Nice and Director of the IRCAN (Institute for Research on Cancer and Aging of Nice), is a specialist in telomere research. Situated at the end of our chromosomes, telomeres are now recognized as pilots in normal and pathological aging processes, in part thanks to Eric Gilson’s research. He’s expecting a lot from laboratory investigations that will be done on the 40,000 coral samples collected throughout the expedition.
Porites Lobata – © Lauric Thiault / Tara Expeditions Foundation
Research on aging in the human species has evolved in recent years. Why?
Eric Gilson : “Not long ago, little was known about the aging process in human beings. We did not know how and why we grow old. Recently, new explanations have begun to emerge much more clearly. It is now established that what causes us to grow old, this wear and tear, originates in our cells. Thanks to research on yeast, zebrafish and mice, among others, these mechanisms are now better understood. The best known clock of cell aging are telomeres. Throughout our lives, with each division of cells ensuring our general functioning, pieces of telomeres are lost. This results in an accumulation of senescent cells, responsible for our aging. This mechanism can accelerate in some of our organs and cause diseases of aging such as cancers, type II diabetes, cardiovascular and respiratory pathologies. The causes for acceleration in cellular aging are many, and some result from our lifestyle: do we play sports, have a good diet, are we stressed at work, etc.?”.
Coral sample – © Yann Chavance / Tara Expeditions Foundation
What aspects of the Tara Pacific expedition and coral interest you for the research on aging in human beings?
Eric Gilson : “As I explained before, knowledge of human aging has made much progress, but we need to study new model organisms to increase this understanding. Not just any models, but those that are close to us and show exceptional particularities in terms of longevity.
If there’s one organism in the animal kingdom that holds a world record for longevity, it’s coral. It has been present on Earth for millions of years and, in addition, is quite close to the genomic organization of humans. To progress in our knowledge of the clocks that control human aging, studying those of coral offers us a wealth of potential discoveries”.
Coral Sample © Yann Chavance / Tara Expeditions Foundation
What are you going to study particularly in the coral?
Eric Gilson : “We already know that coral telomeres are very close to those in humans. Its DNA sequences are identical to ours. Particularly intriguing is what inventions the coral has found throughout its evolution to delay the telomeric clock. What mechanisms have been created by this animal to make its cells more resistant to aging? There would certainly be no coral reefs as large and rich in biodiversity without this extreme longevity.”
More specifically, when you receive your share of samples collected throughout the expedition, what are you going to do with them?
Eric Gilson : “From the tissues of the coral we will extract the DNA. Analysis of these samples by molecular techniques will let us quantify the telomeric DNA present. Remember, it’s the shortening of this DNA in humans which is the mechanism of aging. But back to the Tara expedition: It’s especially interesting because from the thousands of samples we receive, we’ll be able to study the size variations of this telomeric DNA as a function of the environment where the coral lived. We can thus establish new relationships between telomere dynamics and habitat.
Pocillopora meandrina – © Lauric Thiault / Tara Expeditions Foundation
Underlying all this is a basic question we’re asking about ourselves: What happens when a human being is stressed, for example, and the telomere clock accelerates? The relationship we’re going to establish for the coral between lifestyle, environment and habitat will help us understand the functioning of our own machinery. Since we can’t do this with humans, we’ll try to understand what strategies coral invents to escape the various environmental stresses it encounters, and how exactly these work. We know that in humans, disturbance of the telomere clock by stress can lead to serious pathological aging, such as cancer or cardiovascular disease. Among other underlying questions in the research we’re carrying out thanks to Tara, there’s this fundamental inquiry: can we slow down the process of aging, or even reverse it? And if yes, how?”
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