Eicosadomics, proteomics and metabolomics of inflammatory stimulated human fibroblasts reveals specific functions related to chronic inflammation - nuclear proteins of dexamethasone-treated inflammatory stimulated cells

Fibroblasts have only recently been identified as important effector cells in inflammation. In this study, human dermal fibroblasts were inflammatory stimulated with interleukin-1beta and comprehensively analysed with respect to proteins, eicosanoids and metabolites. For eicosadomics, we have established a data-dependent shotgun analysis method capable of identifying inflammation-regulated lipids of yet unknown function. Several classical inflammatory agonists were found induced, including PGA2, PGB2, PGE2 and TXB2, but also modulators such as PGA3 and PGE3, while 8-HETE and several HODE family members remained unaffected. Using targeted metabolomics, several acylcarnithins, phosphatitylcholins and sphingomyelins were found significantly downregulated. Proteome profiling with orbitrap-MS demonstrated the strong induction of several chemokines, metalloproteinases and other effector molecules. Treatment of stimulated fibroblasts with dexamethasone almost completely abrogated the formation of all inflammation-induced eicosanoids and restored levels of acylcarnithins back to normal. As expected, the secretion of IL-6, MMP1, MMP3, CXCL2 and CXCL3 was strongly down-regulated. However, instead of counter-regulating, dexamethasone further enhanced consequences of inflammatory stimulation with respect to CXCL1, CXCL6, complement C3 as well as sphingomyelins. Shotgun secretome data were confirmed by targeted analysis with triple-quadrupol-MS. These molecules have been described to be involved in chronic inflammation. In peripheral blood mononuclear cells, actually dexamethasone successfully downregulated the formation of all detectable inflammation mediators. The present data suggest that successful pharmacological abrogation of the formation of lipid inflammatory mediators in fibroblasts may not suffice to suppress the release of several other powerful inflammatory mediators which we thus understand to be capable of establishing chronic inflammation states.