Interferon regulatory factor 8 induces alveolar macrophage hypoxia/reoxygenation injury via the PINK1/Parkin mitophagy pathway

Abstract

Background: Lung ischemia-reperfusion injury (LIRI) is a complex process and macrophages play a central role in it. Interferon regulatory factor 8 (IRF8) is a transcription factor in the innate immune system, which, together with autophagy, are important components of the mechanisms of LIRI. We aimed to explore the regulatory role of IRF8 in hypoxia/reoxygenation (HR) injury and PINK1-mediated mitophagy.Methods: Cultured NR8383 macrophages were subjected to HR as an in vitro model of LIRI. Cell viability, cell damage and inflammation during HR were evaluated by Cell Counting Kit-8 assay, lactate dehydrogenase assessment and enzyme linked immunosorbent assay, respectively. Meanwhile, PINK1/Parkin-mediated mitochondrial autophagy was detected by quantitative real-time PCR, western blot, transmission electron microscopy and double immunofluorescence labeling method. The effects of IRF8 and PINK1 on cell injury, inflammatory response and autophagy during HR were assessed using IRF8 short-hairpin RNA plasmids and PINK1 overexpression plasmids , respectively. Results: IRF8 inhibition was able to alleviate cell injury, inflammatory response and autophagy while PINK1 overexpression could exacerbate them. Moreover, IRF8 downregulation could reduce the expression of PINK1 in HR injury and attenuate the effects of it. Conclusion: IRF8 was able to induce HR injury via the PINK1/Parkin mitophagy pathway. Inhibition of IRF8 and PINK1/Parkin-mediated mitophagy might be a potential target for the treatment of LIRI.