High resolution scanning electron microscope analysis depicting enhanced NET formation (red arrows) expulsed from neutrophils (blue arrows) in the presence of LPS primed MSC co-cultured with PMA activated neutrophils (middle row, outer left panel) as compared to reduced NETs in non-primed MSCs co-cultured with activated neutrophils (middle row, outer right panel). Of note, TLR4 silenced LPS primed MSCs failed to activate neutrophils and NETs (lower row, outer left panel). TLR4 silenced and non-primed MSCs display reduced NETs in co-cultures with activated neutrophils (lower row, outer right panel), suggesting that PMA activation shares TLR4 signaling components. PMA activated neutrophils alone served as positive control with highly enhanced NETs (upper row, outer right panel) and DMSO treated neutrophils as negative controls (upper row, outer left panel). Red stars indicate neutrophil derived granules. Scale bars: 0.1µm 