Secretion of the Phosphorylated Form of S100A9 from Neutrophils Is Essential for the Proinflammatory Functions of Extracellular S100A8/A9
FRONTIERS IN IMMUNOLOGY
Authors: Schenten, Veronique; Plancon, Sebastien; Jung, Nicolas; Hann, Justine; Bueb, Jean-Luc; Brechard, Sabrina; Tschirhart, Eric J.; Tolle, Fabrice
S100A8 and S100A9 are members of the S100 family of cytoplasmic EF-hand Ca2+-binding proteins and are abundantly expressed in the cytosol of neutrophils. In addition to their intracellular roles, S100A8/A9 can be secreted in the extracellular environment and are considered as alarmins able to amplify the inflammatory response. The intracellular activity of S100A8/A9 was shown to be regulated by S100A9 phosphorylation, but the importance of this phosphorylation on the extracellular activity of S100A8/A9 has not yet been extensively studied. Our work focuses on the impact of the phosphorylation state of secreted S100A9 on the proinflammatory function of neutrophils. In a first step, we characterized the secretion of S100A8/A9 in different stimulatory conditions and investigated the phosphorylation state of secreted S100A9. Our results on neutrophil-like differentiated HL-60 (dHL-60) cells and purified human neutrophils showed a time-dependent secretion of S100A8/A9 when induced by phorbol 12-myristoyl 13-acetate and this secreted S100A9 was found in a phosphorylated form. Second, we evaluated the impact of this phosphorylation on proinflammatory cytokine expression and secretion in dHL-60 cells. Time course experiments with purified unphosphorylated or phosphorylated S100A8/A9 were performed and the expression and secretion levels of interleukin (IL)-1 alpha, IL-1 beta, IL-6, tumor necrosis factor alpha, CCL2, CCL3, CCL4, and CXCL8 were measured by real-time PCR and cytometry bead array, respectively. Our results demonstrate that only the phosphorylated form of the complex induces proinflammatory cytokine expression and secretion. For the first time, we provide evidence that S100A8/PhosphoS100A9 is inducing cytokine secretion through toll-like receptor 4 signaling.
Circulating inflammatory markers and colorectal cancer risk: A prospective case-cohort study in Japan
INTERNATIONAL JOURNAL OF CANCER
Authors: Song, Minkyo; Sasazuki, Shizuka; Camargo, M. Constanza; Shimazu, Taichi; Charvat, Hadrien; Yamaji, Taiki; Sawada, Norie; Kemp, Troy J.; Pfeiffer, Ruth M.; Hildesheim, Allan; Pinto, Ligia A.; Rabkin, Charles S.; Tsugane, Shoichiro
Blood levels of inflammation-related markers may reveal molecular pathways contributing to carcinogenesis. To date, prospective associations with colorectal cancer (CRC) risk have been based on few studies with limited sets of analytes. We conducted a case-cohort study within the Japan Public Health Center-based Prospective Study Cohort II, comparing 457 incident CRC cases during median 18 years follow-up with a random subcohort of 774 individuals. Baseline plasma levels of 62 cytokines, soluble receptors, acute-phase proteins, and growth factor markers were measured using Luminex bead-based assays. We estimated hazard ratios (HRs) associating each marker with CRC risk by Cox proportional hazards models adjusted for potential confounders. Subanalyses compared cases by years after blood draw (vs. >= 5) and anatomical subsite (colon vs. rectum). Linear trends in quantiles of four C-C motif ligand (CCL) chemokines, one C-X-C motif ligand (CXCL) chemokine, and a soluble receptor were nominally associated with CRC risk based on p(trend) < 0.05, but none met false discovery rate corrected statistical significance. HRs for the 4th vs. 1st quartile were: 1.69 for CCL2/MCP1, 1.61 for soluble tumor necrosis factor receptor 2, 1.39 for CCL15/MIP1D, 1.35 for CCL27/CTACK, 0.70 for CXCL6/GCP2 and 0.61 for CCL3/MIP1A. Among cases diagnosed 5+ years after enrollment, CCL2/MCP1, CCL3/MIP1A and CXCL6/GCP2 retained nominal statistical significance. There were no significant differences in associations between colon and rectum. Our findings implicate chemokine alterations in colorectal carcinogenesis, but require replication for confirmation. Noninvasive chemokine assays may have potential application in colorectal cancer screening and etiologic research.