Characterization of a Murine Model System to Study MicroRNA-147 During Inflammatory Organ Injury

Kim, Boyun; Guaregua, Victor; Chen, Xuebo; Zhao, Chad; Yeow, Wanyi; Berg, Nathaniel K.; Eltzschig, Holger K.; Yuan, Xiaoyi

Inflammatory organ injury and sepsis have profound impacts on the morbidity and mortality of surgical and critical care patients. MicroRNAs are small RNAs composed of 20–25 nucleotides that have a significant contribution to gene regulation. MicroRNA-147 (miR-147), in particular, has been shown to have an emerging role in different physiological functions such as cell cycle regulation and inflammatory responses. However, animal model systems to study tissue-specific functions of miR-147 during inflammatory conditions in vivo are lacking. In the present study, we characterize miR-147 expression in different organs and cell types. Next, we generated a transgenic mouse line with a floxed miR-147 gene. Subsequently, we used this mouse line to generate mice with whole-body deletion of miR-147 (miR-147 (−/−)) by crossing “floxed” miR-147 mice with transgenic mice expressing Cre recombinase in all tissues (CMVcre mice). Systematic analysis of miR-147 (−/−) mice demonstrates normal growth, development, and off-spring. In addition, deletion of the target gene in different organs was successful at baseline or during inflammation, including the heart, intestine, stomach, liver, spleen, bone marrow, lungs, kidneys, or stomach. Moreover, miR-147 (−/−) mice have identical baseline inflammatory gene expression compared to C57BL/6 mice, except elevated IL-6 expression in the spleen (7.5 fold, p < 0.05). Taken together, our data show the successful development of a transgenic animal model for tissue and cell-specific deletion of miR-147 that can be used to study the functional roles of miR-147 during inflammatory organ injury.