Wisler, Jon R.Singh, KanhaiyaMccarty, Adara R.Abouhashem, Ahmed Safwat ElsayedChristman, John W.Sen, Chandan K.2022-07-152022-07-152020-03Wisler JR, Singh K, Mccarty AR, Abouhashem ASE, Christman JW, Sen CK. Proteomic Pathway Analysis of Monocyte-Derived Exosomes during Surgical Sepsis Identifies Immunoregulatory Functions. Surg Infect (Larchmt). 2020;21(2):101-111. doi:10.1089/sur.2019.051https://hdl.handle.net/1805/29581Background: Patients with sepsis exhibit significant long-term immunosuppressive sequelae. Monocyte dysfunction is a hallmark of this damage. Circulating exosomes are an important mediator of the systemic signaling events that occur during the septic response; thus, we sought to characterize the contribution of circulating exosomes to the inflammatory process induced during sepsis Methods: Monocyte-derived exosomes were isolated from cultured monocytes from healthy adult donors via stimulation with lipopolysaccharide (LPS) or phosphate-buffered saline (PBS). The proteome was determined by capillary-liquid chromatography-nanospray tandem mass spectrometry (capillary-LC/NT/MS). Using pathway analysis, proteomic networks of exosomes derived from LPS-stimulated monocytes were compared with those isolated from patients with surgical sepsis. Naïve monocytes were then treated with these exosomes and stimulated with LPS to determine the effects on recipient-cell immune function. Results: Proteomic analysis demonstrated 18 differentially expressed proteins (17 down-regulated, one up-regulated) in sepsis-derived exosomes, with 15 differentially expressed proteins (14 down-regulated, one up-regulated) in the LPS-stimulated exosomes. Functional enrichment analysis demonstrated several down-regulated processes, including localization, biogenesis, and metabolic and cellular processes in addition to immune system processes. In LPS-stimulated macrophages, similar down-regulated processes were seen, including metabolic and cellular processes, as well as the response to stimulus. Cells treated with sepsis-derived exosomes or exosomes from LPS-stimulated monocytes demonstrated significant reductions in tumor necrosis factor (TNF)-α generation in response to LPS stimulation. Conclusions: Proteomic analysis of sepsis-derived exosomes and LPS-stimulated, macrophage-derived exosomes exhibited down-regulation of several important protein networks, including the immune response. In addition, human monocytes treated with exosomes from patients with sepsis or LPS-stimulated monocytes demonstrated significant reductions in TNF-α generation in response to LPS stimulation. These data suggest the contribution of circulating exosomes to systemic signaling and immunomodulation during sepsis.en-USPublisher PolicyAnti-inflammationCompensatory anti-inflammatory response syndrome (CARS)ExosomesImmunosuppressionProteomicsSepsisSystemic inflammatory response syndrome (SIRS)Article