The ocean’s little-explored mesophotic zone may yield substances that interfere with the ageing process. TASCMAR is a European Union project that is systematically investigating the possibilities. By Jamal Ouazzani, Yehuda Benayahu and Ioannis Trougakos.
TASCMAR is a European Union-funded research project that investigates the chemical potential of the ocean’s mesophotic zone (see definition below). The goal is to develop sustainable methods for discovering chemical compounds that can be used for application in diverse fields such as health/nutrition, depollution and nature-based cosmetics. Within the key theme of anti-ageing the goal is to evaluate the extracts and pure molecules found on a set of biological assays that will reveal their potential to interfere with the processes of cellular senescence, in vivo ageing and angiogenesis.
As a starting bioresource, TASCMAR is collecting samples of marine invertebrates from biodiversity hotspots around the world. Special emphasis will be given to sustainable bioprospecting, going from collection to cultivation, and developing technologies for sustainable intensification of the active bioresource production.
Exploring under-investigated sea ecosystems
The mesophotic coral-reef ecosystem (MCE) has been defined as comprising the light-dependent communities of corals and other organisms found at depths between 30 and 150 m in tropical and subtropical regions. Due to technical and safety constraints, until the past decade most coral-reef studies have been restricted to the upper ~30 m and therefore data on MCEs have been sparse. Current technological advances, however, such as remotely operated vehicles (Fig 1), and closed-circuit re-breather diving, have now facilitated the investigation of MCEs.
Figure 1. The campaign to collect samples from the mesophotic ecosystem of the Red Sea, conducted by Remotely Operated Vehicle (ROV). Marine invertebrates were collected between 90 and 150 m depth.
Besides reef-building stony corals, octocorals, echinoderms, snails and sponges are common groups of marine invertebrates on many Indo-Pacific and Mediterranean ecosystems down to 30 m and are found to an even greater extent in MCEs. Several studies have been conducted on mesophotic octocorals but the majority of these have been limited to photographic recognition of the resident taxa and did not reveal their actual diversity and abundance. Interestingly, several recent studies indicated that taxa considered rare in shallow reefs might be widespread at mesophotic depths.
The northern Red Sea reefs have been quite extensively studied, albeit mostly confined to the reefs above 30 m. These studies have revealed vast octocoral richness in the Red Sea, as well as of other invertebrate species new to science, yet the MCEs of the Red Sea have remained under-studied. Although situated at the northern-most boundary of coral-reef distribution, the coral reefs of the northern Gulf of Aqaba exhibit exceptionally high within-habitat species diversity (Fig 2). The same applies to other regions, such as Gulf of Thailand, Andaman Sea, eastern and western Mediterranean as well as Indian Ocean islands, whose mesophotic invertebrate species diversity remains unexplored.
MCE invertebrates have the potential to provide novel bio-resources. This, coupled with the scarce data available on MCE invertebrates and their associated microflora—particularly in Red Sea and Thai waters—influenced our decision to make MCE invertebrates the focus of the TASCMAR project.
From organisms to molecules, the need for chemical expertise
After the collection phase, we have a unique opportunity to investigate not only MCE invertebrates as holobionts (assemblages of different species that form ecological units) but also the associated symbionts. A particular focus will be on microorganisms, especially actinomycetes and fungi.
Invertebrates from various locations around the world (Red Sea, Mediterranean, Gulf of Thailand, Andaman Sea, Île de la Réunion and the islands around) will be chemically extracted by automated ASE technology (accelerated solvent extraction) in order to obtain homogenous samples, using a unique scale-up device called the Zippertex (Fig 3 right).
Innovative methods for cultivation of microbial symbionts will be implemented, specifically the agar-supported solid-state cultivation (Ag-SF) coupled with solid-phase extraction (SPE) (see below). Ag-SF applied specifically to marine microorganisms will be scaled up during the project from laboratory to industrial level taking into account the constraints of marine microorganism cultivation and making use of the Platotex device (Fig 3 left), previously developed by the leading project partner, the National Center for Scientific Research (CNRS) in France.
Extraction of target compounds from microbial symbionts includes an innovative, environmentally friendly technology called SPE, in which target compounds are directly transferred from the microorganism to a trapping resin (Fig 4). One of the challenges in the project is to identify compounds produced in the invertebrate ecosystem which may act as a molecular network to stabilize the holobiont by inter- and intra-specific exchanges. This will involve metabolomic comparison between the whole invertebrate extracts and the isolated symbionts extracts. The TASCMAR project consortium counts two of the best-equipped laboratories in Europe, capable of analysis of complex mixtures and of elucidating the structure of challenging natural compounds. The extracts, fractions and pure compounds will be subjected to a panel of molecular, cellular and in vitro bioassays, all dedicated to the discovery of anti-ageing active compounds.
Ageing—a universal challenge, an urgent priority
Organismal ageing is a complex molecular process that relates to the decline of functional capacity and stress resistance leading to increased risk of morbidity and mortality. Given recent findings in model organisms it is evident that healthy lifespan can be prolonged, suggesting that animals have the potential to live longer than they normally do. The need to increase the number of healthy life years is becoming increasingly urgent from both an economic and health perspective and since genetic interventions cannot be applied in humans, many studies have been devoted to the identification of promising natural products. This is because the chemodiversity in nature is immense, meaning that there is great potential in natural sources for finding novel structures capable of modulating the signalling pathways involved in the regulation of ageing.
Across these lines of research, TASCMAR partners will screen ~3000 extracts that will be derived from marine organisms for their bioactivity against proteins known to be involved in the regulation and progression of ageing (see Fig 5). Particular focus will be given to skin extracts and/or pure compounds that promote skin whitening, inhibit wrinkle formation and can protect skin from UV-mediated photoageing. Additional targets will be the activation of cellular intrinsic antioxidant and/or damage-clearing molecular machineries together with tests that will reveal whether the isolated compounds can protect human skin fibroblasts from premature stress-related senescence. The compounds found to be most bioactive for anti-ageing in cell-based assays will then be tested, for example, in vivo in Drosophila flies for the preservation of neuromusculatory functionality during ageing, as well as for longevity-increasing effects.
Besides pharmaceutical activities, the TASCMAR project will also screen extracts and/or pure compounds for cosmeceutical and nutraceutical applications. Microbial symbionts will also be screened for their capacity to degrade chlorinated pollutants, meaning that they could be exploited for bioremediation.
Project coordinator Jamal Ouazzani said “For me and the TASCMAR team, this is a really exciting project due to its global nature. Global because we’re considering marine invertebrates as a whole ecosystem—both the invertebrate and the symbionts. Also global because we’re focussing on diverse industrial applications, from pharmaceuticals and cosmetics to depollution and innovative bio-tech equipment. We’re going to respectfully explore the biodiversity of different locations all around the globe and I can’t wait to see the outcomes! ”
TASCMAR is a collaborative research project funded by the European Union’s Horizon 2020 programme for research and innovation (GA. 634674). The project involves 13 partners from eight countries among which are five academic institutions, six industrials, one non-governmental organization and a consulting company. With a total budget of €6.7 M, TASCMAR is responding to a key challenge set by the European Union ‘Blue Growth’ strategy: the sustainable exploitation of marine compounds.
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