Extracellular vesicle-cargo miR-185-5p reflects type II alveolar cell death after oxidative stress

Abstract

Acute respiratory distress syndrome (ARDS) is a devastating syndrome responsible for significant morbidity and mortality. Diffuse alveolar epithelial cell death, including but not limited to apoptosis and necroptosis, is one of the hallmarks of ARDS. Currently, no detectable markers can reflect this feature of ARDS. Hyperoxia-induced lung injury is a well-established murine model that mimics human ARDS. We found that hyperoxia and its derivative, reactive oxygen species (ROS), upregulate miR-185-5p, but not miR-185-3p, in alveolar cells. This observation is particularly more significant in alveolar type II (ATII) than alveolar type I (ATI) cells. Functionally, miR-185-5p promotes expression and activation of both receptor-interacting kinase I (RIPK1) and receptor-interacting kinase III (RIPK3), leading to phosphorylation of mixed lineage kinase domain-like (MLKL) and necroptosis. MiR-185-5p regulates this process probably via suppressing FADD and caspase-8 which are both necroptosis inhibitors. Furthermore, miR-185-5p also promotes intrinsic apoptosis, reflected by enhancing caspase-3/7 and 9 activity. Importantly, extracellular vesicle (EV)-containing miR-185-5p, but not free miR-185-5p, is detectable and significantly elevated after hyperoxia-induced cell death, both in vitro and in vivo. Collectively, hyperoxia-induced miR-185-5p regulates both necroptosis and apoptosis in ATII cells. The extracellular level of EV-cargo miR-185-5p is elevated in the setting of profound epithelial cell death.

MicroRNA Signatures Associated with Bronchopulmonary Dysplasia Severity in Tracheal Aspirates of Preterm Infants

“…Of the four miRNAs with higher expression in severe BPD infants, two (hsa-miR-545* and miR-185) have been previously implicated in mechanisms of cell cycle arrest, a known effect of prolonged mechanical ventilation and hyperoxia [ 39 , 40 ]. Specifically, miR-545 has been shown to suppress cell proliferation through targeting of cyclins and cyclin-related kinases [ 41 ], and miR-185 has been associated with induction of G1 cell cycle arrest and promotion of necroptosis and apoptosis via receptor-interacting kinases and caspase activity in alveolar epithelial type II cells [ 42 , 43 ]. Moreover, the role of mir-185 in hyperoxia-induced DNA damage and lung epithelial cell death triggered by oxidative stress has been reported using both animal models and human cells [ 43 , 44 ].…”

“…Specifically, miR-545 has been shown to suppress cell proliferation through targeting of cyclins and cyclin-related kinases [ 41 ], and miR-185 has been associated with induction of G1 cell cycle arrest and promotion of necroptosis and apoptosis via receptor-interacting kinases and caspase activity in alveolar epithelial type II cells [ 42 , 43 ]. Moreover, the role of mir-185 in hyperoxia-induced DNA damage and lung epithelial cell death triggered by oxidative stress has been reported using both animal models and human cells [ 43 , 44 ]. Importantly, extracellular vesicles containing miR-185 are significantly elevated following hyperoxia-induced cell death in alveolar type II epithelial cells [ 43 ].…”

“…Moreover, the role of mir-185 in hyperoxia-induced DNA damage and lung epithelial cell death triggered by oxidative stress has been reported using both animal models and human cells [ 43 , 44 ]. Importantly, extracellular vesicles containing miR-185 are significantly elevated following hyperoxia-induced cell death in alveolar type II epithelial cells [ 43 ]. While we did not characterize the composition of TAs regarding extracellular vesicles, it is possible that the increased levels of miR-185 found in TAs from severe BPD infants (who are subjected to higher and more prolonged hyperoxia than mild/moderate BPD infants) could represent a signal of hyperoxia-induced epithelial cell damage via increased extracellular vesicle miR-185 cargo.…”

Tracheal Aspirate miRNA Signatures in Preterm Infants with Severe Bronchopulmonary Dysplasia

“…Of the four miRNAs with higher expression in severe BPD infants, two (hsa-miR-545* and miR-185) have been previously implicated in mechanisms of cell cycle arrest, a known effect of prolonged mechanical ventilation and hyperoxia [30,31]. Specifically, miR-545 has been shown to suppress cell proliferation through targeting of cyclins and cyclin-related kinases [32], and miR-185 has been associated with induction of G1 cell cycle arrest and promotion of necroptosis and apoptosis via receptor-interacting kinases and caspase activity in alveolar epithelial type II cells [33,34]. Moreover, the role of mir-185 in hyperoxia-induced DNA damage and lung epithelial cell death triggered by oxidative stress has been reported using both animal models and human cells [34,35].…”

“…Specifically, miR-545 has been shown to suppress cell proliferation through targeting of cyclins and cyclin-related kinases [32], and miR-185 has been associated with induction of G1 cell cycle arrest and promotion of necroptosis and apoptosis via receptor-interacting kinases and caspase activity in alveolar epithelial type II cells [33,34]. Moreover, the role of mir-185 in hyperoxia-induced DNA damage and lung epithelial cell death triggered by oxidative stress has been reported using both animal models and human cells [34,35]. Importantly, extracellular vesicles containing miR-185 are significantly elevated following hyperoxia-induced cell death in alveolar type II epithelial cells [34].…”