Background and aims Newborns are more susceptible to microbial infections than are adults. To explore the molecular mechanisms underlying the increased susceptibility of newborns to infection, we compared the expression profile of miRNAs in response to LPS stimulation in vitro in leukocytes from newborns and adults.
Methods We obtained blood samples from 10 healthy term newborns and 11 healthy adults. Whole blood cells were cultured in vitro with or without LPS. After 2 h of culture, leukocytes were isolated, and total RNA was extracted. The miRCURY LNA Array (v.14.0) was used to detect miRNAs expression profile. TLR-related genes were studied by microarray and PCR arrays. A bioinformatics analysis was used to identify the potential biological processes and targets involved in the TLR signals affected by these miRNAs.
Results A total of 53 miRNAs and 29 TLR-related genes were differentially expressed between newborns and adults. The bioinformatics analysis showed that the potential target genes of these differential miRNAs were involved in regulation of cellular biosynthetic process, regulation of gene expression, regulation of macromolecule biosynthetic process, etc. Twelve potential miRNA-mRNA interaction sites were found within the cDNA sequences of ten differentially expressed TLR signalling pathway genes.
Conclusions We identified a differential miRNA expression profile during LPS-induced acute inflammation in leukocytes derived from newborns and adults. The target genes of these differential miRNA were mainly involved in several biological processes, and these miRNAs may play important roles in the regulation of TLR signals. However, the precise mechanisms require further validation.