Whole Transcriptome Analysis Using Next-Generation Sequencing of Sterile-Cultured Eisenia andrei for Immune System Research

Abstract

Recently, earthworms have become a useful model for research into the immune system, and it is expected that results obtained using this model will shed light on the sophisticated vertebrate immune system and the evolution of the immune response, and additionally help identify new biomolecules with therapeutic applications. However, for earthworms to be used as a genetic model of the invertebrate immune system, basic molecular and genetic resources, such as an expressed sequence tag (EST) database, must be developed for this organism. Next-generation sequencing technologies have generated EST libraries by RNA-seq in many model species. In this study, we used Illumina RNA-sequence technology to perform a comprehensive transcriptome analysis using an RNA sample pooled from sterile-cultured Eisenia andrei. All clean reads were assembled de novo into 41,423 unigenes using the Trinity program. Using this transcriptome data, we performed BLAST analysis against the GenBank non-redundant (NR) database and obtained a total of 12,285 significant BLAST hits. Furthermore, gene ontology (GO) analysis assigned 78 unigenes to 24 immune class GO terms. In addition, we detected a unigene with high similarity to beta-1,3-glucuronyltransferase 1 (GlcAT-P), which mediates a glucuronyl transfer reaction during the biosynthesis of the carbohydrate epitope HNK-1 (human natural killer-1, also known as CD57), a marker of NK cells. The identified transcripts will be used to facilitate future research into the immune system using E. andrei.

Annotation of nerve cord transcriptome in earthworm Eisenia fetida

“…Few significant research works based on the transcriptome and expressed sequence tag analysis of various earthworm species have been performed in the recent past. These researches have revealed some of the key findings like expression of globin-related genes and fibrinolytic enzymes in the midgut sample of earthworm Eisenia andrei [18] , differential expression of putative genes under inorganic, organic and agrochemical xenobiotic exposure in earthworm Lumbricus rubellus [23] , genes regulating the anterior regeneration in Perionyx excavatus [24] and identification of genes responsible for immune response in Eisenia andrei [25] . Considering the ecological and environmental aspects of the earthworm E. fetida several transcriptome analysis were undertaken to extract maximum information regarding their genetic and molecular resources.…”

Bacterial Engulfment Mechanism Is Strongly Conserved in Evolution Between Earthworm and Human Immune Cells

“…Even though the MyD88-dependent/independent TLR pathway is well conserved across the evolution ( 66 ), limited data for E. andrei are available regarding the MyD88 involvement in earthworm immune response. Whole transcriptome analysis of E. andrei has identified several immune-related sequences, including MyD88 as an adaptive molecule for MAPK signaling activated by TLR ( 67 ). As our results suggest, there is no significant difference between MyD88 expression levels in unstimulated and bacteria stimulated coelomocytes.…”

Understanding nutrition and immunity in disease management

“…9 Development of molecular and genetic resources may help achieve a more complete understanding of earthworms as a genetic model that may facilitate research of the immune system. 13 …”