siRNA-Mediated Timp1 Silencing Inhibited the Inflammatory Phenotype during Acute Lung Injury

Abstract

Acute lung injury is a complex cascade process that develops in response to various damaging factors, which can lead to acute respiratory distress syndrome. Within this study, based on bioinformatics reanalysis of available full-transcriptome data of acute lung injury induced in mice and humans by various factors, we selected a set of genes that could serve as good targets for suppressing inflammation in the lung tissue, evaluated their expression in the cells of different origins during LPS-induced inflammation, and chose the tissue inhibitor of metalloproteinase Timp1 as a promising target for suppressing inflammation. We designed an effective chemically modified anti-TIMP1 siRNA and showed that Timp1 silencing correlates with a decrease in the pro-inflammatory cytokine IL6 secretion in cultured macrophage cells and reduces the severity of LPS-induced acute lung injury in a mouse model.

Cholesterol-Modified Anti-Il6 siRNA Reduces the Severity of Acute Lung Injury in Mice

“…Previously, we demonstrated the possibility of reducing the severity of acute injury in the lungs after intranasal instillation of anti-Timp1 siRNA complexed with cationic liposomes [35]. We showed that the reduction of inflammation was accompanied by a reduced number of neutrophils in the BAL fluid.…”

“…The treatment of mice by anti-Il6 siRNA not only significantly changed the proportion of neutrophils in BAL but also reduced the absolute number of leukocytes compared with LPS-challenged mice, which was not achieved by the anti-Timp1 siRNA treatment. The relative change in inflammatory processes evaluated by histological scoring also showed positive trends: 2.5 and 3.2 folds for anti-Timp1 and anti-Il6 siRNAs, respectively [35]. However, these differences in therapy efficacy may also be due to the chosen targets as well as to different delivery methods and target cells.…”

“…However, these differences in therapy efficacy may also be due to the chosen targets as well as to different delivery methods and target cells. In a previous study [35], anti-Timp1 delivery to the target lung cells was performed using cationic lipids. In this study, we delivered anti-Il6 siRNA by covalent attachment to cholesterol in order to deliver it to alveolar macrophages.…”

“…The time intervals were selected based on our previously obtained data on the dynamics of activation of IL6 synthesis during LPS-mediated ALI [35]. Data showed that the Il6 mRNA level increased by two orders of magnitude in LPS-challenged mice compared to the untreated group (Figure 2B).…”

Advances in Biomarkers for Diagnosis and Treatment of ARDS

“…Chernikov et al studied the efficiency of siRNA-mediated TIMP-1 silencing as an approach to reduce the inflammatory phenotype during ALI. The authors demonstrated that by dampening TIMP-1, inflammation was lessened and respiratory function was improved in an ALI experiment, pointing to the possibility that TIMP-1 manipulation could be a potential remedy for ARDS [95].…”