TREK-1 localization in trabecular meshwork by immunohistochemistry

PRIMARY OUTCOME

TREK-1 protein localization and distribution

EXPECTED OUTCOMES

## Primary Outcomes **TREK-1 Expression Confirmation**: TREK-1 protein detected in human trabecular meshwork cells with predominant membrane localization (membrane-to-cytoplasm ratio ≥2.0 in ≥80% of positive cells). Expected membrane MFI: 85 ± 22 arbitrary units (AU) in normal donors. **Cellular Specificity**: TREK-1+ cells co-localize with conventional aqueous outflow pathway markers (α-smooth muscle actin, N-cadherin) in 70-85% of cases, confirming trabecular meshwork cell identity. ## Secondary Outcomes **Age-Related Changes**: TREK-1 membrane expression shows progressive reduction with donor age (slope: -0.8 AU/year, R² = 0.34, p = 0.02). Glaucoma samples trend toward lower membrane TREK-1 (estimated difference: -15 to -25 AU vs. age-matched controls).

SUCCESS CRITERIA

## Primary Success Criteria **Specific Immunofluorescence**: TREK-1 signal-to-noise ratio ≥4.0 in positive cells vs. isotype control sections. Membrane-localized TREK-1 must be clearly distinguishable from cytoplasmic background using standard confocal imaging parameters. **Reproducibility**: Inter-batch coefficient of variation (CV) for TREK-1 membrane MFI ≤ 15% across 3 independent staining runs on the same donor sample. ## Secondary Success Criteria **Biological Specificity**: TREK-1 expression positively correlates with known TM marker expression (AQP1, CD44) with Spearman ρ ≥ 0.6, confirming authentic TM cell population detection. **Subcellular Precision**: TREK-1 membrane localization confirmed by co-localization with pan-cadherin (Σ = 0.68 ± 0.12 Pearson's coefficient), validating true membrane rather than vesicular/perinuclear pool.

PROTOCOL

# TREK-1 Localization in Trabecular Meshwork by Immunohistochemistry Protocol ## Phase 1: Tissue Collection and Processing (Days 1-7) **Human Trabecular Meshwork Acquisition**: Obtain human donor eyes (n=12, ages 50-75, both sexes) from eye banks within 24 hours of death. Enucleate eyes, rinse in sterile PBS, and dissect trabecular meshwork (TM) tissue from the iridocorneal angle. Flash-freeze 4 tissue blocks in OCT compound for cryosectioning (8 μm thickness). Fix remaining tissue in 4% PFA (4°C, 4 hours) for paraffin embedding (5 μm sections). **Quality Control**: Verify tissue integrity via H&E staining. Exclude samples with >20% epithelial disruption or significant autolysis. Store slides at -80°C until use. ## Phase 2: Immunohistochemical Staining (Days 8-14) **Antigen Retrieval**: Deparaffinize slides in xylene (2× 5 min), rehydrate through graded ethanol series. Perform heat-induced epitope retrieval (HIER) in citrate buffer (pH 6.0, 95°C, 20 min). Cool slides to room temperature, wash 3× in PBS. **Primary Antibody Incubation**: Block in 5% normal donkey serum (1 hour, RT). Incubate with primary antibodies: rabbit anti-TREK-1 (1:100, Alomone Labs #ANT-012) and mouse anti-GBF2 (Golgi marker, 1:200, 1 hour, RT). Include isotype controls (rabbit IgG, mouse IgG1). Wash 3× PBS. **Secondary Antibody and Detection**: Apply donkey anti-rabbit Alexa Fluor 594 (1:500, 1 hour, RT) and donkey anti-mouse Alexa Fluor 488 (1:500, 1 hour, RT). Counterstain nuclei with DAPI (300 nM, 5 min). Mount in ProLong Gold antifade reagent. Image within 48 hours. ## Phase 3: Confocal Imaging and Quantitative Analysis (Days 15-21) **Microscopy**: Image on Leica SP8 confocal microscope (63× oil immersion objective, NA 1.4). Acquire z-stacks (0.5 μm steps, 20 slices per field) from 3 non-overlapping TM regions per slide. Set laser power and gain to avoid saturation in isotype controls. **Quantification Protocol**: Using ImageJ/Fiji: (1) segment TREK-1+ cells based on signal threshold (3× background), (2) define subcellular compartments (membrane, cytoplasm, nucleus) using marker-based masks, (3) measure mean fluorescence intensity (MFI) per compartment. Calculate membrane-to-cytoplasm ratio for each cell (n≥50 cells per sample). **Statistical Analysis**: Compare TREK-1 membrane localization between glaucoma and normal donor eyes. Use Mann-Whitney U test for non-parametric comparison (primary outcome: membrane MFI). Correlate with donor age and post-mortem time as covariates.

LINKED HYPOTHESES

HTML iframe

<iframe src="http://scidex.ai/artifact/exp-38a174ab-52de-44cb-8eee-dbf284a45903?embed=1" width="100%" height="600" style="border:0;border-radius:8px"></iframe>

Markdown link

[TREK-1 localization in trabecular meshwork by immunohistochemistry](http://scidex.ai/artifact/exp-38a174ab-52de-44cb-8eee-dbf284a45903)

Direct URL

http://scidex.ai/artifact/exp-38a174ab-52de-44cb-8eee-dbf284a45903

Preview