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Updated: Aug 16, 2025
Blood Collection from the American Horseshoe Crab, Limulus Polyphemus
Published on: October 13, 2008
Transcriptomic Signature of Horseshoe Crab Carcinoscorpius rotundicauda Hemocytes' Response to Lipopolysaccharides
Maria E Sarmiento1, Kai Ling Chin2, Nyok-Sean Lau3
1School of Health Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian 16150, Malaysia.
Insights
This study reveals how horseshoe crab (HSC) immune cells respond to bacterial components. Transcriptomic analysis identified key genes and pathways involved in the innate immune defense of Carcinoscorpius rotundicauda.
Area of Science:
- * Marine biology and immunology.
- * Invertebrate immune responses.
- * Genomics and transcriptomics.
Background:
- * Horseshoe crabs (HSCs) possess a primitive innate immune system crucial for survival.
- * Hemocytes, the blood cells of HSCs, contain defense molecules against pathogens.
- * Understanding HSC immunity offers insights into evolutionary biology and potential biomedical applications.
Purpose of the Study:
- * To investigate the transcriptomic changes in Carcinoscorpius rotundicauda hemocytes upon stimulation with lipopolysaccharides (LPS).
- * To identify genes and pathways involved in the innate immune response of HSCs to gram-negative bacteria.
Main Methods:
- * Isolation and purification of Carcinoscorpius rotundicauda hemocytes.
- * Challenge of hemocytes with lipopolysaccharides (LPS).
- * RNA-sequencing (Illumina HiSeq) and differential gene expression analysis.
Main Results:
- * RNA-sequencing generated millions of high-quality reads from control and LPS-stimulated hemocytes.
- * LPS stimulation resulted in significant differential gene expression: 79 genes upregulated and 265 genes downregulated.
- * Affected genes are involved in critical immune pathways including cytoskeleton, Toll/Imd, apoptosis, MAPK signaling, and phagocytosis.
Conclusions:
- * This study elucidates the molecular mechanisms underlying the horseshoe crab's response to LPS.
- * The findings provide valuable data on HSC innate immunity, particularly in response to gram-negative bacterial components.
- * The identified differentially expressed genes offer targets for further research into HSC immune function.
Abstract:
Carcinoscorpius rotundicauda (C. rotundicauda) is one of the four species of horseshoe crabs (HSCs). The HSC hemocytes store defense molecules that are released upon encountering invading pathogens. The HSCs rely on this innate immunity to continue its existence as a living fossil for more than 480 million years. To gain insight into the innate mechanisms involved, transcriptomic analysis was performed on isolated C. rotundicauda hemocytes challenged with lipopolysaccharides (LPS), the main components of the outer cell membrane of gram-negative bacteria. RNA-sequencing with Illumina HiSeq platform resulted in 232,628,086 and 245,448,176 raw reads corresponding to 190,326,253 and 201,180,020 high-quality mappable reads from control and LPS-stimulated hemocytes, respectively. Following LPS-stimulation, 79 genes were significantly upregulated and 265 genes were downregulated. The differentially expressed genes (DEGs) were related to multiple immune functional categories and pathways such as those of the cytoskeleton, Toll and Imd, apoptosis, MAP kinase (MAPK), inositol phosphate metabolism, phagosome, leucocyte endothelial migration, and gram-negative bacterial infection, among others. This study provides important information about the mechanisms of response to LPS, which is relevant for the understanding the HSCs' immune response.
