title: Thrombomodulin Protects Against Bacterial Keratitis, Is Anti-Inflammatory, but Not Angiogenic.
abstract: OBJECTIVE
  Thrombomodulin (TM) is a multidomain, transmembrane protein with anti-inflammatory properties. Thrombomodulin domain (D) 1 is lectin-like, interacting with Lewis Y antigen on lipopolysaccharide, and with HMGB1, while TMD23 is associated with angiogenic and anti-inflammatory functions. Thus, we tested if TM is protective against Pseudomonas aeruginosa keratitis and whether it enhanced corneal vascularity.
  
  
  METHODS
  Eyes of C57BL/6 (B6) mice were injected with recombinant TM (rTM), rTMD1, or PBS subconjunctivally before and intraperitoneally after infection with P. aeruginosa. Clinical scores, photography with a slit lamp, RT-PCR, ELISA, myeloperoxidase (MPO) assay, viable bacterial plate counts, and India ink perfusion were used to assess the disease response and corneal vascularity (rTM only).
  
  
  RESULTS
  Recombinant TM versus PBS treatment reduced clinical scores and corneal opacity. Corneal mRNA levels for HMGB1 were unchanged, but proinflammatory molecules IL-1β, CXCL2, NF-κB, TLR4, and RAGE were decreased; anti-inflammatory molecules SIGIRR and ST2 were increased. ELISA confirmed the mRNA data for HMGB1, IL-1β, and CXCL2 proteins. Both neutrophil influx and viable bacterial plate counts also were decreased after rTM treatment. Protein levels for angiogenic molecules VEGF, VEGFR-1, and VEGFR-2 were measured at 5 days post infection and were not different or reduced significantly after rTM treatment. Further, perfusion with India ink revealed similar vessel ingrowth between the two groups. Similar studies were performed with rTMD1, but disease severity, mRNA, proteins, MPO, and plate counts were not changed from controls.
  
  
  CONCLUSIONS
  These data provide evidence that rTM treatment is protective against bacterial keratitis, does not reduce HMGB1, and is not angiogenic.
authors.forename: Sharon A
authors.initials: SA
authors.lastname: McClellan
authors.forename: Sandamali A
authors.initials: SA
authors.lastname: Ekanayaka
authors.forename: Cui
authors.initials: C
authors.lastname: Li
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Jiang
authors.forename: Ronald P
authors.initials: RP
authors.lastname: Barrett
authors.forename: Linda D
authors.initials: LD
authors.lastname: Hazlett
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use*; D015169:Colony Count, Microbial; D003315:Cornea / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D015818:Eye Infections, Bacterial / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D007634:Keratitis / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism; D009504:Neutrophils / Q000502:physiology; D020011:Protective Agents / Q000627:therapeutic use*; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D011550:Pseudomonas aeruginosa; D012333:RNA, Messenger / Q000378:metabolism; D018180:Thrombomodulin / Q000627:therapeutic use*; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D016328:NF-kappa B; D020011:Protective Agents; D012333:RNA, Messenger; D018180:Thrombomodulin; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1; D040301:Vascular Endothelial Growth Factor Receptor-2