The mechanisms and factors that induce trained immunity in arthropods and mollusks

Abstract

Besides dividing the organism’s immune system into adaptive and innate immunity, it has long been thought that only adaptive immunity can establish immune memory. However, many studies have shown that innate immunity can also build immunological memory through epigenetic reprogramming and modifications to resist pathogens’ reinfection, known as trained immunity. This paper reviews the role of mitochondrial metabolism and epigenetic modifications and describes the molecular foundation in the trained immunity of arthropods and mollusks. Mitochondrial metabolism and epigenetic modifications complement each other and play a key role in trained immunity.

Transforming Aquaculture Through Vaccination: A Review on Recent Developments and Milestones

“…Recent insights pinpoint towards the direction that the aquatic invertebrate immune system can indeed be primed, therefore opening the gateways to immunization within their setting as well. Approaches to aquatic invertebrate immunization can include both vaccination and immunomodulation or immunostimulation through dietary manipulations [52][53][54][55].…”

DNA Methylation Machinery in Gastropod Mollusks

“…Geyer et al ( 2017) measured the expression of DNMT1, DNMT2, and MBD2/3 in the hemocytes, albumin gland, head/foot, stomach, ovotestis, and hepatopancreas from mature specimens of the freshwater snail, Biomphalaria glabrata, infected with S. mansoni [38]. The measured values for DNMT1 and DNMT2 in hemocytes, which are key cells for the snail's innate immune response to parasite infection [105], were much higher compared to those in other body parts [38]. DNMT1 is central to preserving DNA methylation patterns during cell division [67], and hence, its elevated expression in these cells might imply a greater need for maintaining existing DNA methylation patterns in genes crucial for immune responses.…”

“…This could involve perpetuating the methylation status of specific immune-related genes, influencing their expression during immune cell development, activation, and response to stimuli. Elevated DNMT2 expression in hemocytes may also reflect its role in establishing new DNA methylation patterns or modifying existing ones in response to immune challenges [105]. This could involve targeting specific genomic regions associated with immune-related pathways or responses.…”

“…The gastropod genome contains low to moderate 5mC levels, with moderate inter-species and inter-organ variation. The TET-DNMTs interplay modulates the epigenetic landscape via reversion of DNA methylation by TET enzymes when gene expression is active [105]. Data related to DNA methylation erasers (i.e., TET genes) in snails are limited and inconclusive, despite the confirmed presence of small amounts 5hmC in the gastropod genome.…”