Injury-Induced Innate Immune Response During Segment Regeneration of the Earthworm, Eisenia andrei

• Published in: International journal of molecular sciences Vol. 22; no. 5; p. 2363
• Main Authors: Bodó, Kornélia, Kellermayer, Zoltán, László, Zoltán, Boros, Ákos, Kokhanyuk, Bohdana, Németh, Péter, Engelmann, Péter
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 27.02.2021; MDPI
• Subjects: Animals; Apoptosis; Cell growth; Cell Proliferation; Enzymes; Gene Expression Regulation; Immune response; Immune system; Immunity, Innate; Morphology; Oligochaeta - genetics; Oligochaeta - immunology; Oligochaeta - physiology; Pattern recognition; Phosphatase; Regeneration; Smooth muscle; Toxins, Biological; Vertebrates; Wounds and Injuries; cell proliferation; innate immunity; regeneration; earthworm; apoptosis; coelomocytes; gene expression
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms22052363

Regeneration of body parts and their interaction with the immune response is a poorly understood aspect of earthworm biology. Consequently, we aimed to study the mechanisms of innate immunity during regeneration in Eisenia andrei earthworms. In the course of anterior and posterior regeneration, we documented the kinetical aspects of segment restoration by histochemistry. Cell proliferation peaked at two weeks and remitted by four weeks in regenerating earthworms. Apoptotic cells were present throughout the cell renewal period. Distinct immune cell (e.g., coelomocyte) subsets were accumulated in the newly-formed blastema in the close proximity of the apoptotic area. Regenerating earthworms have decreased pattern recognition receptors (PRRs) (e.g., TLR, except for scavenger receptor) and antimicrobial peptides (AMPs) (e.g., lysenin) mRNA patterns compared to intact earthworms. In contrast, at the protein level, mirroring regulation of lysenins became evident. Experimental coelomocyte depletion caused significantly impaired cell divisions and blastema formation during anterior and posterior regeneration. These obtained novel data allow us to gain insight into the intricate interactions of regeneration and invertebrate innate immunity.