A typical C-type lectin, perlucin-like protein, is involved in the innate immune defense of whiteleg shrimp Litopenaeus vannamei

The cell types and developmental trajectories of shrimp cells based on the transcriptional level have not been established, and gene expression profile and function at the single-cell level is unclear. We aimed to use scRNA-seq to construct a single-cell resolution transcriptional map of hepatopancreas and haemocytes in shrimp to analyse the molecular mechanisms of the immune response to ammonia nitrogen stress. In the present study, seven cell clusters were successfully identified in each of the two tissues (haemocytes, Hem1-7; hepatopancreas, Hep1-7) based on specifically-expressed marker genes. The developmental starting points of haemocytes and hepatopancreatic cells were Hem2 and Hep1, respectively. We propose that Hem2 has oligopotent potential as the initiation site for haemocyte development and that Hem4 and Hem5, located at the end of development, are the most mature immune cell types in haemocytes. Hep5 and Hep6 were the developing terminal cells of hepatopancreas. The antioxidant system and proPO system of shrimp were activated under ammonia nitrogen stress. A large number of DEGs were involved in oxidative stress, detoxification metabolism, and immune defence. In particular, important response genes such as AMPs, proPO, and GST were not only marker genes for identifying cell groups but also played an important role in shrimp cell differentiation and functional plasticity. By successfully applying 10× Genomics based scRNA-seq to the study of shrimp, the single-cell transcriptional profiles of hepatopancreatic cells and haemocytes of shrimp innate immune responses under ammonia stress were constructed for the first time. This atlas of invertebrate hepatopancreatic cells and haemocytes at single-cell resolution identifies molecular events that underpin shrimp innate immune system responses to stress.

Section: Discussionmentioning

confidence: 99%

Single-Cell Sequencing Reveals Types of Hepatopancreatic Cells and Haemocytes in Black Tiger Shrimp (Penaeus monodon) and Their Molecular Responses to Ammonia Stress

Yang

Jiang

et al. 2022

“…In this study, chitinase-related genes (chitinase-3-like protein 1 and acidic mammalian chitinase-like) were significantly down-regulated in the three experimental groups as a result of immunosuppression. After invasion of pathogenic microorganisms, the first and most important step of the innate immune response in crustaceans is the identification of pathogen associated molecular patterns on the pathogen surface through various pattern recognition receptors ( 22 ), such as C-type lectin, which plays an important role in the innate immune response in crustaceans ( 23 ). Several lectin-related DEGs were identified as down-regulated genes in this study, including C-type lectin domain family 6 member A-like and ladder-like lectin in the three experimental groups.…”

Section: Discussionmentioning

confidence: 99%

Comprehensive Transcriptomic and Metabolomic Analysis of the Litopenaeus vannamei Hepatopancreas After WSSV Challenge

Zhai

et al. 2022

Litopenaeus vannamei is the major farmed shrimp species worldwide. White spot disease due to white spot syndrome virus (WSSV) is severely affecting shrimp worldwide, causing extensive economic losses in L. vannamei culture. This is the first study that applied combined transcriptomic and metabolomic analysis to study the effects on the L. vannamei hepatopancreas after WSSV challenge. Our transcriptomic data revealed differentially expressed genes (DEGs) associated with immunity, apoptosis, the cytoskeleton and the antioxidant system in the hepatopancreas of L. vannamei. Metabolomic results showed that WSSV disrupts metabolic processes including amino acid metabolism, lipid metabolism and nucleotide metabolism. After challenged by WSSV, immune-related DEGs and differential metabolites (DMs) were detected in the hepatopancreas of L. vannamei, indicating that WSSV may damage the immune system and cause metabolic disorder in the shrimp. In summary, these results provide new insights into the molecular mechanisms underlying L. vannamei’s response to WSSV.

“…Scavenger receptors (SRs) are major endocytic receptors that can bind Gram-negative and Gram-positive bacteria to promote hemocyte phagocytosis ( 47 , 48 ). Perlucin is a typical C-type lectin, which can directly agglutinate bacterial pathogens to restrict their spread in plasma, and is involved in regulating the innate immunity by regulating phagocytosis and AMP expression ( 49 ). Toll and toll-like receptors are involved in pathogen recognition in plants, invertebrates and vertebrates ( 50 ).…”

Section: Discussionmentioning

confidence: 99%

The Enhanced Immune Protection in Small Abalone Haliotis diversicolor Against a Secondary Infection With Vibrio harveyi

Tuo

Bai

et al. 2021

In recent years, more and more studies have shown that early pathogenic bacterial infection in invertebrates can enhance immunity and significantly reduce mortality when reinfected with the same pathogen. There are mechanisms to explain this phenomenon, but they are relatively few. In addition, dose-dependent primary infection is also associated with increased immunity. In the present study, the initial infection dose and mortality of abalone Haliotis diversicolor after reinfection with Vibrio harveyi were recorded, and the mechanism of immune enhancement was investigated by the transcriptomic response of abalone after two successive stimuli with V. harveyi. Priming with different concentrations of pathogen can enhance immunity; however, higher concentration is not always better. Compared with the first exposure, more genes were up-regulated after the second exposure. Among the commonly expressed genes, the immune related genes were significantly or persistently highly expressed after two infections and included pattern recognition receptors as well as immune effectors, such as toll-like receptors, perlucin 4, scavenger receptor class B-like protein, cytochrome P450 1B1-like, glutathione S-transferase 6, lysozyme and so on; in addition, these immune-related genes were mainly distributed in the pathways related to phagocytosis and calcium signaling. Among the specifically expressed genes, compared with the first infection, more genes were involved in the immune, metabolic and digestive pathways after the second infection, which would be more conducive to preventing the invasion of pathogens. This study outlined the mechanism of immune enhancement in abalone after secondary infection at the global molecular level, which is helpful for a comprehensive understanding of the mechanism of immune priming in invertebrates.