Characterization of Recombinant Human PRG4 as an Ocular Surface Boundary Lubricant
Bibliographic record
Abstract
Introduction : Dry-eye disease involves tear film instability that can result in surface-to-surface contact between the cornea and eyelid or contact lens, where boundary lubrication can be dominant1. Motivated by the recent discovery that proteoglycan 4 (PRG4, a mucin-like glycoprotein originally discovered in synovial fluid as a boundary lubricant2), functions as an ocular surface boundary lubricant3, advances in recombinant protein expression technology4, and PRG4’s potential use as a friction-reducing contact lens coating, the objectives of this study were to: 1) biochemically characterize recombinant human PRG4 (rh- PRG4); and 2) assess the boundary lubricating properties of rh-PRG4, both before and after autoclave sterilization, at a cornea-contact lens material (PDMS) biointerface. Methods : SDS-PAGE western blot analysis using a variety of anti-PRG4 antibodies and lectins was performed on native PRG4 (nPRG4) and rh-PRG4 samples, both nonreduced and reduced, with and without enzymatic removal of O-linked glycosylations. Human corneas and PDMS were articulated against each other, subject to physiological loads of 8-25 kPa, at effective sliding velocities of 0.3-30 mm/s. Test lubricant sequences were A) saline, rh-PRG4 @300μg/mL, nPRG4 @300μg/mL, and saline; and B) saline, autoclaved rh-PRG4 @300μg/mL, rh-PRG4 @300μg/mL, and saline. Static and kinetic coefficients of friction were calculated. Results : rh-PRG4 demonstrated similar immunoreactivity to nPRG4, and effectively lowered friction at the cornea-PDMS biointerface. Western blotting indicated immunoreactive rh-PRG4 bands had a similar apparent molecular weight (MW) to nPRG4, and decreased appropriately upon reduction as well as enzymatic removal of glycosylations. Kinetic friction coefficients, which were highest in saline (0.31±0.06 to 0.40±0.06, mean±SEM), were similar in rh-PRG4 (0.12±0.01 to 0.25±0.03) and nPRG4 (0.19±0.02 to 0.28±0.03) across all velocities. Autoclaved rh-PRG4 had similar values to rh-PRG4 as well (0.19±0.02 to 0.26±0.04, 0.16±0.02 to 0.26±0.02, respectively). Conclusions : rh-PRG4 demonstrates similar biochemical and ocular surface lubricating properties to nPRG4, and may function as an effective friction-reducing contact lens coating.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".