The promotion of cytoskeleton integration and redox in the haemocyte of shrimp Litopenaeus vannamei after the successive stimulation of recombinant VP28

VP28 protein has been reported to work as a "vaccine" to protect the host from white spot syndrome, but the detailed mechanism of vaccination with VP28 protein in shrimp is still far from well understood. In the present study, whole transcriptomes of shrimp haemocytes were sequenced using the SOLiD4 platform after the successive VP28 stimulation. Eight single-end fragment libraries were constructed and sequenced in the four groups including the VP28-VP28, PBS-VP28, PBS-PBS and BLANK group, and there were 243,949,667 single-end reads with length of 50 bp obtained totally, with 14,800 genes further identified. After reads mapping and transcript assembling, 1027, 1539, 1158, 1091 and 1300 genes in five differentially expressed gene lists were obtained in the comparison of VP28-VP28 versus PBS-VP28, VP28-VP28 versus PBS-PBS, VP28-VP28 versus BLANK, PBS-VP28 versus PBS-PBS and PBS-VP28 versus BLANK, respectively. There were 555 differentially expressed genes responsive to the single VP28 stimulation after grouping the PBS-VP28_BLANK and PBS-VP28_PBS-PBS gene lists, and 269 ones responsive to the successive VP28 stimulation after grouping the VP28-VP28_BLANK, VP28-VP28_PBS-PBS and VP28-VP28_PBS-VP28 gene lists. In the GO enrichment analysis of the genes responsive to the single VP28 stimulation, five immune-related GO terms were observed among 14 increased terms, which included defense response to bacterium, response to stimulus, disruption of cells of other organism, killing of cells of other organism and response to bacterium. It was worth noting that the GO terms, response to stimulus and response to stress, were the most common annotation ones which accounted 28.7% and 18.8% of the total differently expressed genes, respectively. For the genes responsive to the successive VP28 stimulation, terms including actin filament-based movement and myosin heavy chain binding were mostly enriched in the Biological Process and Molecular Function category, respectively. In the Cellular Component category, the enriched GO terms were myosin VII complex, myosin V complex, myosin VI complex and myosin II complex. Furthermore, the most abundant GO term was oxidation-reduction process, followed by single-organism transport, neurogenesis and translation for 214 genes only responsive to successive VP28 stimulation. These results collectively indicated that the successive VP28 stimulation could modulate cytoskeleton integration and redox to promote the phagocytosis activity of shrimp haemocytes, which might protect effectively for shrimp against WSSV infection. (C) 2014 Elsevier Ltd. All rights reserved.