Defying the Odds: Innate Immunity in Invertebrates Living in Deep-Sea Extreme Environments

Dear Colleagues,

The deep-sea is one of the most extreme and inhospitable environments on Earth, and yet many deep-sea creatures display unique adaptations to withstand the extreme hydrostatic pressure, complete darkness, and cold temperatures that affect their metabolism. In some areas such as hydrothermal vents or cold seeps, some creatures exhibit remarkable physiological changes to the presence of highly toxic compounds, including methane and hydrogen sulfide. Under such extreme conditions, however, invertebrates inhabiting these deep-sea ecosystems must have evolved survival strategies to overcome the problem of microbial threat and thus, the need for immunity. The interactions between microorganisms and host defense mechanisms is a decisive factor in the survival of marine invertebrates, as their reliance on an innate immune system, rather than adaptive immunity, is essential for rapidly recognizing and responding to pathogens in the microbe-rich deep-sea environment. The study of deep-sea invertebrates living in deep-sea environments, such as hydrothermal vents and cold seeps, may not only deliver insights into evolutionary immunology and the specialization of innate immune mechanisms to cope with extreme conditions but may also contribute to biotechnological and biomedical approaches.

In this Special Issue, we aim to discuss the unique features of deep-sea invertebrates’ innate immunity, aiming to understand the evolutionary, molecular, cellular, and ecological adaptations promoting survival in extreme habitats. As the host’s first line of defense, innate immunity key components are addressed, including pattern recognition receptors (PRRs), antimicrobial peptides (AMPs), the prophenoloxidase (proPO) system, and cellular immune responses mediated by hemocytes. Moreover, the role of symbiotic microbial communities in deep-sea invertebrates’ innate immune responses are presumably essential, as these special cellular symbionts can modulate host immune responses, outcompete pathogens, and contribute to the overall health and resilience of marine invertebrates. Knowledge of these mechanisms in deep-sea species offers important lessons on how immune systems evolve under extreme deep-sea environmental conditions.

Dr. Raul Bettencourt
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Marine Drugs is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2900 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.