Studies On The JAK/STAT Immune Signaling Pathway Of Scylla Paramamosain Under Low Salinity Stress

Salinity significantly affects the growth,survival,metabolism and immune defense of shrimp and crabs.It is demonstrated that Janus kinase/signal transducer and activator of transcription(JAK/STAT)signal pathway plays a very important role in the immune response of pathogens.However,whether the JAK/STAT signaling pathway affects the innate immunity of crustacean under hyposalinity stress and its mechanism of immune response is still unclear and needs further study.Therefore,we took the S.Paramamosain,an important aquatic economic species in China,as the research object to study whether it can play the function of immune regulation through JAK/STAT signaling pathway under low salinity stress.1.Cloning and sequence analysis of Suppressor of cytokine signaling(SOCS)in the JAK/STAT signaling pathway.In this study,the gene cloning and sequence analysis of SOCS,an inhibitor of JAK/STAT signal pathway,was completed for the first time in the S.Paramamosain.SpSOCS contains an open reading frame of 1020 bp,which encodes 339 amino acids with a molecular weight of 36.98 KDa.The results of homology comparison showed that the homology of SOCS protein between S.Paramamosain and Eriocheir sinensis,Marsupenaeus Japonicus and Litopenaeus vannamei was 76%,75% and 74%,respectively.Bioinformatics analysis showed that SpSOCS has the same SH2 and SOCS BOX domains in the SOCS family.The phylogenetic tree analysis showed that SpSOCS clustered with SOCS of E.sinensis and M.Japonicus,and then clustered with other invertebrates such as Bombyx mori and other invertebrates,while the vertebrate SOCS clustered into another branch.2.Effects of RNA interference on JAK/STAT/SOCS signaling pathway on immune regulation of Scylla Paramamosain under low salinity stress.In this study,RNA interference technology was used to interfere with the JAK/STAT signaling pathway of S.Paramamosain under low salinity stress,aiming to explore whether S.Paramamosain can activate the immune response through JAK/STAT signaling pathway and its mechanism under salinity stress.The expression levels of related immune genes were detected by q PCR technique,and the changes of apparent immune defense indexes were studied by physiological and biochemical methods.In this study,the results showed that JAK/STAT signal pathway may not regulate the immune response by affecting the number of hematocytes in S.Paramamosain.It was speculated that it could positively regulate the expression of prophenolic oxidase activator(Sp PPAF)and prophenolic oxidase(Sppro PO)genes,but did not affect prophenolic oxidase activity(pro PO)and phenolic oxidase activity(PO).It was speculated that positive regulation of antimicrobial peptides(including Sp ALF,Sp Cru,Sp GRP and Sp Hyastatin),lysozyme(Sp Lyz)and C-type lectin(Sp C-type)could affect the antimicrobial activity,lysozyme activity and agglutination activity,respectively.Therefore,we hypothesized that hyposalinity stress could trigger an innate immune response through activation of the JAK/STAT signaling pathway.In this study,the JAK/STAT signaling pathway and its immune regulation mechanism of S.Paramamosain were preliminally analyzed under low salinity stress.This study not only provided a theoretical basis for the research of crustacean environmental immunology,but also provided technical support for the healthy breeding of economic shrimp and crabs.