TY - JOUR T1 - Proteomic, biomechanical and functional analyses define neutrophil heterogeneity in systemic lupus erythematosus JF - Annals of the Rheumatic Diseases JO - Ann Rheum Dis SP - 209 LP - 218 DO - 10.1136/annrheumdis-2020-218338 VL - 80 IS - 2 AU - Kathleen R Bashant AU - Angel M Aponte AU - Davide Randazzo AU - Paniz Rezvan Sangsari AU - Alexander JT Wood AU - Jack A Bibby AU - Erin E West AU - Arlette Vassallo AU - Zerai G Manna AU - Martin P Playford AU - Natasha Jordan AU - Sarfaraz Hasni AU - Marjan Gucek AU - Claudia Kemper AU - Andrew Conway Morris AU - Nicole Y Morgan AU - Nicole Toepfner AU - Jochen Guck AU - Nehal N Mehta AU - Edwin R Chilvers AU - Charlotte Summers AU - Mariana J Kaplan Y1 - 2021/02/01 UR - http://ard.bmj.com/content/80/2/209.abstract N2 - Objectives Low-density granulocytes (LDGs) are a distinct subset of proinflammatory and vasculopathic neutrophils expanded in systemic lupus erythematosus (SLE). Neutrophil trafficking and immune function are intimately linked to cellular biophysical properties. This study used proteomic, biomechanical and functional analyses to further define neutrophil heterogeneity in the context of SLE.Methods Proteomic/phosphoproteomic analyses were performed in healthy control (HC) normal density neutrophils (NDNs), SLE NDNs and autologous SLE LDGs. The biophysical properties of these neutrophil subsets were analysed by real-time deformability cytometry and lattice light-sheet microscopy. A two-dimensional endothelial flow system and a three-dimensional microfluidic microvasculature mimetic (MMM) were used to decouple the contributions of cell surface mediators and biophysical properties to neutrophil trafficking, respectively.Results Proteomic and phosphoproteomic differences were detected between HC and SLE neutrophils and between SLE NDNs and LDGs. Increased abundance of type 1 interferon-regulated proteins and differential phosphorylation of proteins associated with cytoskeletal organisation were identified in SLE LDGs relative to SLE NDNs. The cell surface of SLE LDGs was rougher than in SLE and HC NDNs, suggesting membrane perturbances. While SLE LDGs did not display increased binding to endothelial cells in the two-dimensional assay, they were increasingly retained/trapped in the narrow channels of the lung MMM.Conclusions Modulation of the neutrophil proteome and distinct changes in biophysical properties are observed alongside differences in neutrophil trafficking. SLE LDGs may be increasingly retained in microvasculature networks, which has important pathogenic implications in the context of lupus organ damage and small vessel vasculopathy. ER -