Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal disease. Recent findings have shown a marked metabolic reprogramming associated with changes in mitochondrial homeostasis and autophagy during pulmonary fibrosis. The microRNA-33 (miR-33) family of microRNAs (miRNAs) encoded within the introns of sterol regulatory element binding protein (SREBP) genes are master regulators of sterol and fatty acid (FA) metabolism. miR-33 controls macrophage immunometabolic response and enhances mitochondrial biogenesis, FA oxidation, and cholesterol efflux. Here, we show that miR-33 levels are increased in bronchoalveolar lavage (BAL) cells isolated from patients with IPF compared with healthy controls. We demonstrate that specific genetic ablation of miR-33 in macrophages protects against bleomycin-induced pulmonary fibrosis. The absence of miR-33 in macrophages improves mitochondrial homeostasis and increases autophagy while decreasing inflammatory response after bleomycin injury. Notably, pharmacological inhibition of miR-33 in macrophages via administration of anti–miR-33 peptide nucleic acids (PNA-33) attenuates fibrosis in different in vivo and ex vivo mice and human models of pulmonary fibrosis. These studies elucidate a major role of miR-33 in macrophages in the regulation of pulmonary fibrosis and uncover a potentially novel therapeutic approach to treat this disease.
Authors
Farida Ahangari, Nathan L. Price, Shipra Malik, Maurizio Chioccioli, Thomas Bärnthaler, Taylor S. Adams, Jooyoung Kim, Sai Pallavi Pradeep, Shuizi Ding, Carlos Cosmos Jr., Kadi-Ann S. Rose, John E. McDonough, Nachelle R. Aurelien, Gabriel Ibarra, Norihito Omote, Jonas C. Schupp, Giuseppe DeIuliis, Julian A. Villalba Nunez, Lokesh Sharma, Changwan Ryu, Charles S. Dela Cruz, Xinran Liu, Antje Prasse, Ivan Rosas, Raman Bahal, Carlos Fernández-Hernando, Naftali Kaminski
Figure 6
The absence of miR-33 in macrophages induces mitophagy in response to injury and alters cytokine-induced gene expressions in AM.
