Recently, amphioxus has served as a model for studying the origin and evolution of vertebrate immunity. However, little is known about how microRNAs (miRNAs) are involved in the immune defense in amphioxus. In a recent article, researchers from Nanjing University identified the amphioxus miRNAs in the acute-phase response to lipopolysaccharide (LPS).
In their study, the time point for the peak of immune response in amphioxus after LPS challenge was determined by evaluating the expression of Branchiostoma belcheri toll-like receptor 1, NF-κb (c-Rel), and big defensin which react with pathogen-associated molecular patterns(PAMPs). 12 h was then chosen as the point to perform miRNA microarray analysis to select the differentially expressed miRNAs. Furthermore, quantitative real-time PCR was used to detect the expression patterns of selected amphioxus miRNAs under effective LPS challenge during the time course.
Relative expression of bbtTLR1, NF-κb (c-Rel), and big defensin
The expression of bbtTLR1 (A), NF-κb (c-Rel) (B) and big defensin (C) in the gills of B. belcheri challenged with LPS at different time points. The data are expressed as a ratio to the expression level of 18s rRNA and are plotted as the means ± SD.
MicroRNA microarray data revealed that the miRNA expression file was significantly changed after LPS stimulation. The changes of the 10 most upregulated and 7 most downregualted miRNAs in gills of the amphioxus following challenge with LPS revealed a temporal induction kinetic.
This current study provides valuable information and insight into the molecular mechanism of innate immunity and the evolution of the miRNA family.