Project description:Background: Histomonas meleagridis is an anaerobic, intercellular parasite that infects the Galliformes such as turkeys and chickens. In recent years, the reemergence of Histomoniasis has caused serious economic losses as drugs to treat the disease have been banned. At present, studies on H. meleagridis mainly focus on virulence, gene expression analysis, and the innate immunity of the host. However, there are no studies on differential expression of miRNAs (DEMs) in host immune and inflammatory response induced by H. meleagridis infection in chickens. In this study, the expression profile of cecum miRNA at 10 and 15 days post-infection (DPI) with Chinese JSYZ-F strain H. meleagridis was studied by high-throughput sequencing. Results: Compared with the control group, 94 and 127 DEMs were found in the cecum of infected chickens at 10 DPI (CE vs CC) and 15 DPI (CEH vs CCH), respectively, of which 60 DEMs were shared at two-time points. Gene Ontology (GO) enrichment analysis of the target genes of DEMs showed that 881 and 1027 GO terms were significantly enriched at 10 and 15 DPI. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways of the target genes of DEMs showed that only 5 and 3 pathways were significantly enriched at 10 and 15 DPI, respectively. The integrated analysis of miRNA–gene network revealed that the DEMs played important roles in the host immune and inflammatory responses to H. meleagridis infection by dynamically regulating the expression of immune and inflammation-related cytokines. Conclusion: Our results not only suggested that host miRNA expression was dynamically altered by H. meleagridis and host, but also revealed that more miRNAs and genes were involved in the later stage of the disease. In addition, host and H. meleagridis regulated the expression of immune and inflammation-related cytokines to respond to H. meleagridis infection. Our results will contribute to future research on miRNA-target interaction during H. meleagridis infection in chickens and provide new ideas for H. meleagridis control.