Novel insights into host-pathogen interactions of large yellow croakers(Larimichthys crocea)and pathogenic bacterium Pseudomonas plecoglossicida using time-resolved dual RNA-seq of infected spleens

Host-pathogen interactions are highly complex,involving large dynamic changes in gene expression during infection. These interactions are fundamental to understanding anti-infection immunity of hosts, as well as the pathogenesis of pathogens. For bacterial pathogens interacting with animal hosts, timeresolved dual RNA-seq of infected tissue is difficult to perform due to low pathogen load in infected tissue. In this study, an acute infection model of Larimichthys crocea infected by Pseudomonas plecoglossicida was established. The spleens of infected fish exhibited typical symptoms, with a maximum bacterial load at two days post-injection(dpi). Time-resolved dual RNA-seq of infected spleens was successfully applied to study hostpathogen interactions between L. crocea and P.plecoglossicida. The spleens of infected L. crocea were subjected to dual RNA-seq, and transcriptome data were compared with those of noninfected spleens or in vitro cultured bacteria. Results showed that pathogen-host interactions were highly dynamically regulated, with corresponding fluctuations in host and pathogen transcriptomes during infection. The expression levels of many immunogenes involved in cytokine-cytokine receptor,Toll-like receptor signaling, and other immunerelated pathways were significantly up-regulated during the infection period. Furthermore, metabolic processes and the use of oxygen in L. crocea were strongly affected by P. plecoglossicida infection. The WGCNA results showed that the metabolic process was strongly related to the entire immune process.For P. plecoglossicida, the expression levels of motility-related genes and flagellum assemblyrelated genes were significantly up-regulated. The results of this study may help to elucidate the interactions between L. crocea and P.plecoglossicida.

Age-related effects of estrogen on the expression of estrogen receptor (ER) α and β mRNA in the ovariectomized (OVX) monkey hypothalamus

In the present study, we reported distribution of ERα and ER β mRNAs in the hypothalamus of young and old ovariectomized （OVX） rhesus macaques. The ERα were detected in all six major vestiblular nuclei which included arcuate nucleus （ARC） , paraventricularis nucleus （PVN） , periventricular nucleus （PeriV） , supraoptic nucleus （SON）, medial prioptic nucleus （MPN） and lateral hypotbalamus area （LHA）. However, the ERβ mRNA can also detected in those nuclei excerpt SON, but the signals of ERβ mRNA were weaker than those of ERα mRNA. We observed that the degree of expression of ERs mRNA were different in most nucleus of old and young monkeys. The ERα mRNAs were highly expressed in ARC and SON in young monkeys compared with old monkeys. Moderate amount of ERα mRNAs hybridization signals and weak signals were observed in LHA, and MPN both in young and old monkeys. In contrast, only lower level of ERα hybridization signal were observed in PVN and PeriV in young monkeys, and the signals of ERα were very low in those nucleus of old monkeys. In general, the expression of ERβ mRNA were weaker than that of ERα mRNA in above nucleus excerpt LHA. The relatively higher density of ERβ hybridization signals have been observed in the LHA in young monkey compared with old monkeys. Low amount of. ERβ mRNA hybridization signals were observed in the ARC, PVN and MPN, and no age differences were seen in PVN and MPN of those monkeys. In PeriV, we observed some signals in young monkey and a few signals in old monkeys. It was different from the rodent in which we did not found ERβ hybridization signal in SON. This study showed that both of the two estrogen receptors not only had the same pattern of expression but also had many different patterns of expression. The different expression of ERα and ERβ mRNAs in the young and old monkey brain may imply diverse functions in different regions of the monkey brain.

Dual RNA-seq provides novel insight into the roles of dks A from Pseudomonas plecoglossicida in pathogenhost interactions with large yellow croakers(Larimichthys crocea)

Pseudomonas plecoglossicida is a rod-shaped,gram-negative bacterium with flagella.It causes visceral white spot disease and high mortality in Larimichthys crocea during culture,resulting in serious economic loss.Analysis of transcriptome and quantitative real-time polymerase chain reaction(PCR)data showed that dks A gene expression was significantly up-regulated after 48 h of infection with Epinephelus coioides(log2 FC=3.12,P<0.001).RNAi of five sh RNAs significantly reduced the expression of dks A in P.plecoglossicida,and the optimal silencing efficiency was 96.23%.Compared with wild-type strains,the symptoms of visceral white spot disease in L.crocea infected with RNAi strains were reduced,with time of death delayed by 48 h and mortality reduced by 25%.The dks A silencing led to a substantial down-regulation in cellular component-,flagellum-,and ribosome assembly-related genes in P.plecoglossicida,and the significant up-regulation of fli C may be a way in which virulence is maintained in P.plecoglossicida.The GO and KEGG results showed that RNAi strain infection in L.crocea led to the down-regulation of inflammatory factor genes in immune-related pathways,which were associated with multiple immune response processes.Results also showed that dks A was a virulence gene in P.plecoglossicida.Compared with the wild-type strains,RNAi strain infection induced a weaker immune response in L.crocea.