Trimannose-coupled antimiR-21 for macrophage-targeted inhalation treatment of acute inflammatory lung damage [mirnome_mouse]
Recent studies of severe acute inflammatory lung disease including COVID-19 have identified macrophages to drive pulmonary hyperinflammation and long-term damage such as fibrosis. Here, we report on the development of a first-in-class, carbohydrate-coupled inhibitor of microRNA-21 (RCS-21), as a therapeutic means against pulmonary hyperinflammation and fibrosis. MicroRNA-21 was among the strongest upregulated microRNAs in COVID-19 and in mice with acute inflammatory lung damage and was the strongest expressed microRNA in pulmonary macrophages. Chemical linkage of an oligonucleotide inhibitor of microRNA-21 to trimannose achieved rapid and specific delivery to macrophages upon inhalation in mice. RCS-21 reversed pathological activation of macrophages and prevented pulmonary dysfunction and fibrosis after acute lung damage in mice.  In human lung tissue infected with SARS-CoV-2 ex vivo, RCS-21 effectively prevented the exaggerated inflammatory response. Our data imply trimannose-coupling for effective and selective delivery of inhaled oligonucleotides to pulmonary macrophages and report on a first mannose-coupled candidate therapeutic for COVID-19. Overall design: Here, we sequenced a) total lungs from bleomycin and control mice and b) different pulmonary cell types from WT mice.