Preliminary Study On The Mechanism Of MyD88 Under The Condition Of Pasteurella Multocida Infection From Goat

Pasteurella multocida(Pm)is an important zoonotic pathogen,which can colonize various organs of the host.The current studies mainly focus on Pm-induced lung infection,but there are still reports of animal heart infection.Therefore,the study of Pm-infected heart is beneficial to improve the understanding of host’s immune mechanism to Pm infection.In addition,different serotypes of Pm have potential pathogenicity differences.To sum up,this study focused on the colonization of two different serotypes of Pm(Pm HN01 and Pm HN02)in the heart of mice,and compared and analyzed the differences in pathological changes and immune mechanisms.1,The establishment of Pasteurella multocida heart infection modelAfter resuscitation and identification,two strains of Pm were used to construct the heart infection model,and heart tissues were collected for pathogen identification and histopathological examination.According to the 16 s r RNA sequences,the genetic evolution relationship of the two strains was analyzed.Besides,their virulence factors were compared and analyzed.The results showed that the two strains were Pm HN01 and Pm HN02,respectively.The pathological changes of the heart caused by Pm HN01 were more serious.Further analysis showed that Pm HN01 had high homology with Danish Pm 38725.In addition,Pm HN02 were predicted to have more virulence factors than Pm HN01.2.Functional study on immune response of cardiac MyD88 to Pasteurella multocidaAccording to the constructed infection model,heart tissues were collected for transcriptome sequencing and bioinformatics analysis,including RNA quality and sequencing quality inspection,functional enrichment analysis of differentially expressed genes(DEGs),gene set enrichment analysis,gene set variation analysis and gene and protein level verification of DEGs.The results showed that the RNA quality was qualified and the sequencing quality was high.DEGs shared by the two experimental groups were mainly enriched in innate immune-related pathways.The DEGs specific to Pm HN01 group were mainly enriched in inflammation-related pathways,while the specific DEGs of Pm HN02 group were mainly enriched in recognition,endocytosis and adhesion-related pathways.Both Pm HN01 and Pm HN02 activate innate immune-related pathways,among which Pm HN02 strain activates toll-like receptor signaling pathway.In addition,the the expression of the core molecule(MyD88)in this pathway was significantly up-regulated at the gene and protein levels.3.Bioinformatics analysis of goat MyD88 proteinAccording to the amino acid sequence of goat MyD88 protein downloaded from NCBI database,the physical and chemical properties,hydrophilicity and hydrophobicity analysis,N-glycosylation sites analysis,signal peptides,secondary structures,transmembrane domains and protein-protein interaction network were predicted.The results showed that goat MyD88 protein was unstable and hydrophilic protein without transmembrane domain or signal peptide.And MyD88 interacted with many immune-related proteins,such as TLR4 and CD14.To sum up,two kinds of heart infection models were successfully established in this study.The two strains caused typical inflammatory reactions in the heart,mainly involving innate immune response-related pathways.Among them,Toll-like receptor signaling pathway and its core factor MyD88 played an important role in Pm HN02 infection.This study provides candidate genes for goat breeding of Pm resistance.