The effects of an autocrine loop mediated by platelet-activating factor (PAF) in HEC-1A cells are reverted by uteroglobin

Platelet-activating factor blockade inhibits the T-helper type 17 cell pathway and suppresses psoriasis-like skin disease in K5.hTGF-β1 transgenic mice

Platelet-activating factor (PAF), a potent biolipid mediator, is involved in a variety of cellular transduction pathways and plays a prominent role in inducing inflammation in different organs. We used K5.hTGF-β1 transgenic mice, which exhibit an inflammatory skin disorder and molecular and cytokine abnormalities with strong similarities to human psoriasis, to study the pathogenic role of PAF. We found that injecting PAF into the skin of transgenic mice led to inflammation and accelerated manifestation of the psoriatic phenotype by a local effect. In contrast, injecting mice with PAF receptor antagonist PCA-4248 lowered the PAF level (most likely by depressing an autocrine loop) and neutrophil, CD68(+) cell (monocyte/macrophage), and CD3(+) T-cell accumulation in the skin and blocked progression of the psoriasis-like phenotype. This effect of PAF blockade was specific and similar to that of psoralen-UV-A and was paralleled by a decrease in abnormally elevated mRNA and/or protein levels of T-helper type 17 cell-related cytokines IL-17A, IL-17F, IL-23, IL-12A, and IL-6 and its transcription factor signal transducer and activator of transcription 3. In contrast, PCA-4248 treatment up-regulated mRNA levels of cyclooxygenase-2 and IL-10 in dorsal skin and release of IL-10 in serum and skin. Interfering with PAF may offer the opportunity to develop novel therapeutic strategies for inflammatory psoriasis and associated comorbidities, including metabolic syndrome and atherosclerosis, in which the IL-17 axis may be involved.

Mass spectrometry-based proteomic analyses in contact lens-related dry eye

PURPOSE

To identify potential protein biomarkers associated with dry eye in contact lens wearers.

METHODS

Upon enrollment, current galyfilcon A contact lens wearers completed a previously described questionnaire used to classify dry eye status. Approximately 5 microL of aqueous tears were carefully sampled from the inferior-lateral tear prism of each eye using glass microcapillaries. A variety of proteomic approaches were used to compare samples including quantification by Bradford analyses, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) (alone in varying percentages and with MultiPlex analyses for posttranslational modifications), nano-liquid chromatography tandem mass spectometry (nano-LC-MS/MS), and differential gel electrophoresis.

RESULTS

Twenty-one subjects were enrolled in the study (age 31.3 +/- 11.6 years). Eleven of the subjects were classified with contact lens-related dry eye, while the remaining 10 were normal contact lens wearers. Across all proteomic approaches, several proteins (including several glycoproteins) were identified as potential biomarkers associated with dry eye disease state. In summary across the approaches used, extracellular proteins identified to be altered included beta-2 microglobulin, proline rich 4, lacritin, and secretoglobin 1D1, which were found to be decreased in the dry eye state. Secretoglobin 2A2, serum albumin, glycoprotein 340, and prolactin-inducible protein were all found to be increased in the dry eye state.

CONCLUSIONS

Dry eye in contact lens wearers is related to several changes in the tear film protein. While functional studies for these candidate proteins are ongoing, initial insights into the functions of these proteins suggest roles in altered tear secretion, in addition to possible increased susceptibility to infection.