Effects of AntagomiRs on Different Lung Diseases in Human, Cellular, and Animal Models

Murdaca, Giuseppe; Tonacci, Alessandro; Negrini, Simone; Greco, Monica; Borro, Matteo; Puppo, Francesco; Gangemi, Sebastiano

It is well established that miRNAs are pleiotropic molecules involved in almost all major biological processes. This concept was particularly studied in the lung, where specific miRNAs demonstrated to cooperate with organ development and pulmonary diseases. During the last years, much data has been collected on this topic, with special regards to obstructive and restrictive lung diseases [91] [92] [93] . In fact, as Sessa and Hata [94] reported, a typical miRNAs expression profile was noticed and different miRNAs play an active role among different processes including hemostasis, viral infection, and inflammation. Lung-specific miRNAs can be used as novel biomarkers in lung disorders. To date, several pieces of research focused on specific lung disease miRNAs expression patterns. However, specific miRNAs expression profiles may be noticed also among different organs. Previously, Wang et al. [20] conducted a study on rats, demonstrating that two specific miRNAs (miR-195 and miR-200c) were peculiarly expressed in the lung, while eight miRNAs were co-expressed in the lung and heart and one miRNA was co-expressed in the lung and kidney. As interest increased on this topic, accessible databases as, for example, MiRmine were created in order to allow researchers to retrieve expression profiles of single or multiple miRNAs for a specific tissue or cell line, either normal or with disease information [95] . According to our results, miR-21 seems to be the most represented miRNA among lung conditions. MiR-21 is often up-regulated in lung carcinoma. This fact is believed to be a result of the capacity of miR-21 to inhibit tumor suppressor phosphatase and tensin-homolog [96] . Collison et al. [24] characterized miRNAs expression among house dust mite allergic mice. A group was treated with antagomiRs that inhibited the function of specific miRNAs in the lung, and the other group received standard steroid therapy with dexamethasone. Finally, inflammatory lesions and airway hyper-responsiveness were measured. Researchers found that, although miR-21 and let-7b were highly expressed during allergic inflammation, blockade of their function was ineffective at modulating the expression of disease. On the other hand, Kim et al. [27] conducted a study on BALB/c mice noticing that antagomiR-21 increased phosphatase and tensin homolog (PTEN) levels (p < 0.05). Treatment with Ant-21 reduced phosphoinositide 3-kinase (PI3K) activity and restored histone deacetylase (HDAC2) levels (p < 0.05), leading to suppression of airway hyper-responsiveness and to restore of steroid sensitivity to allergic airway disease. Lee et al. [60] also investigated allergic inflammation among mouse models, reporting that MiR-21 expression was down-regulated in mice lungs treated with anti-miR-21. In fact, specific antagomiR reduced both eosinophil count (p < 0.01) and Th2 cytokines levels, including IL-5 and IL-13 in mice BAL fluid (p < 0.05). MiRNA21 demonstrated positive effects also upon lung ischemia. Ischemia/reperfusion injury (IRI) is the primary cause of acute lung injury (ALI) and primary graft dysfunction (PGD) after lung transplantation [97] . Li et al. [28] conducted a study on murine lung ischemia/reperfusion (I/R) and in vitro hypoxia/reoxygenation (H/R) models demonstrating that pre-treatment of mesenchymal stromal cells with miR-21-5p antagomiR ameliorated IRI in the lung. Regarding PAH, Pullamsetti et al. [25] conducted a study both on animal models and cell lines d