title: Milk fat globule-epidermal growth factor-factor VIII downregulates interleukin-17 expression in sepsis by modulating STAT3 activation.
abstract: BACKGROUND
  Milk fat globule-epidermal growth factor-factor VIII (MFG-E8) is a secretory glycoprotein with a known role in inflammation. In sepsis, interleukin (IL)-17 acts as a proinflammatory cytokine to exaggerate systemic inflammation. We hypothesize that MFG-E8 downregulates IL-17 expression in sepsis.
  
  
  METHODS
  Sepsis was induced in 8-week-old male C57BL/6 mice by cecal ligation and puncture (CLP). Recombinant mouse MFG-E8 (rmMFG-E8) at a dosage of 20 μg/kg body weight or phosphate-buffered saline was concurrently injected. After 10 hours, blood and spleen samples were harvested for analysis. For in vitro studies, splenocytes isolated from healthy mice pretreated with rmMFG-E8 and splenocytes from MFG-E8 knockout (mfge8(-/-)) mice were stimulated with phorbol 12-myristate 13-acetate (PMA) and ionomycin, followed by measurement of IL-17 expression with either quantitative PCR or enzyme-linked immunosorbent assay.
  
  
  RESULTS
  At 10 hours after CLP, rmMFG-E8 inhibited the elevated levels of IL-17 protein in serum by 31%, compared with the vehicle. In the spleen, rmMFG-E8 reduced the upregulated IL-17 mRNA and protein levels by 81% and 51%, respectively. This correlated with a significant reduction in organ injury markers AST and ALT in sepsis after administration of rmMFG-E8. In vitro treatment of splenocytes isolated from healthy mice with rmMFG-E8 showed significant downregulation in PMA/ionomycin-induced IL-17 expression. In contrast, CD4 T-cells from mfge8(-/-) mice showed significant upregulation of IL-17 compared with wild-type mice. The phosphorylated level of signal transducer and activator of transcription 3 (STAT3) was downregulated in spleen tissue of septic mice treated with rmMFG-E8. Conversely, mfge8(-/-) mice showed increased phosphorylated STAT3 compared with wild-type mice after sepsis.
  
  
  CONCLUSIONS
  Our findings demonstrate MFG-E8-mediated downregulation of IL-17 expression, implicating its potential as a novel therapeutic agent against sepsis.
authors.affiliation: Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY.
authors.forename: Cindy
authors.initials: C
authors.lastname: Cen
authors.affiliation: Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY; Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, NY.
authors.forename: Monowar
authors.initials: M
authors.lastname: Aziz
authors.affiliation: Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY; Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, NY.
authors.forename: Weng-Lang
authors.initials: WL
authors.lastname: Yang
authors.affiliation: Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Nicastro
authors.affiliation: Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY.
authors.forename: Gene F
authors.initials: GF
authors.lastname: Coppa
authors.affiliation: Department of Surgery, Hofstra North Shore-LIJ School of Medicine, Manhasset, NY; Center for Translational Research, The Feinstein Institute for Medical Research, Manhasset, NY. Electronic address: pwang@nshs.edu.
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D000954:Antigens, Surface / Q000378:metabolism* / Q000627:therapeutic use; D015415:Biomarkers / Q000378:metabolism; D015536:Down-Regulation; D004797:Enzyme-Linked Immunosorbent Assay; D020381:Interleukin-17 / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008894:Milk Proteins / Q000378:metabolism* / Q000627:therapeutic use; D060888:Real-Time Polymerase Chain Reaction; D050796:STAT3 Transcription Factor / Q000378:metabolism*; D018805:Sepsis / Q000188:drug therapy / Q000378:metabolism*; D013154:Spleen / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D000954:Antigens, Surface; D015415:Biomarkers; D020381:Interleukin-17; C490919:Mfge8 protein, mouse; D008894:Milk Proteins; D050796:STAT3 Transcription Factor; C494087:Stat3 protein, mouse