Spantide I decreases type I cytokines, enhances IL-10, and reduces corneal perforation in susceptible mice after Pseudomonas aeruginosa infection.
OBJECTIVE
To determine the effects of blocking substance P (SP) interactions with its major receptor (NK1-R) using the antagonist spantide I in susceptible mice infected with Pseudomonas aeruginosa.


METHODS
Immunohistochemistry and enzyme immunosorbent assay (EIA) tested levels of SP in the cornea of B6 and BALB/c mice. B6 mice were treated with spantide, and after infection, slit lamp examination; clinical score; bacterial counts; and myeloperoxidase (MPO), RT-PCR, ELISA, and polymorphonuclear (PMN) cell chemotaxis assays were performed.


RESULTS
SP corneal levels were significantly elevated constitutively and after infection in the B6 more than in BALB/c mice. Spantide treatment of B6 mice significantly decreased the number of perforated corneas, bacterial counts, and PMNs. mRNA levels for type I cytokines (e.g., IFN-gamma) as well as MIP-2, IL-6, TNF-alpha, and IL-1beta (mRNA and protein) also were significantly reduced after spantide treatment. The type II cytokine IL-10 (mRNA and protein) was elevated, whereas TGF-beta mRNA levels were unchanged after spantide treatment. PMN chemotaxis was induced by SP and other neuropeptides in vitro, but was not affected by spantide I. mRNA for neurokinin-1-receptor-1 (NK-1R) was detected in the normal and infected corneas and on macrophages (Mphis), but not on PMNs (unstimulated or stimulated with endotoxin [LPS]). Spantide treatment of Mphis reduced IL-1beta after LPS+SP treatment but not after either alone.


CONCLUSIONS
The SP antagonist Spantide provides a novel approach to reduce type 1 and enhance the type 2 cytokine IL-10 in the infected cornea of B6 mice, leading to a significant reduction in corneal perforation and improved disease outcome.
Hazlett
Linda D
LD
Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA. lhazlett@med.wayne.edu
McClellan
Sharon A
SA
Barrett
Ronald P
RP
Liu
Jianhua
J
Zhang
Yunfan
Y
Lighvani
Shahrzad
S
D000818:Animals; D002634:Chemotaxis, Leukocyte; D003315:Cornea / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D003320:Corneal Ulcer / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D016207:Cytokines / Q000378:metabolism*; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D015818:Eye Infections, Bacterial / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005260:Female; D007124:Immunoenzyme Techniques; D016753:Interleukin-10 / Q000378:metabolism; D008264:Macrophages / Q000502:physiology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000502:physiology; D009195:Peroxidase / Q000378:metabolism; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D011550:Pseudomonas aeruginosa; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012422:Rupture, Spontaneous / Q000188:drug therapy; D013373:Substance P / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000627:therapeutic use
D016207:Cytokines; D016753:Interleukin-10; D013373:Substance P; C042867:spantide; D009195:Peroxidase