• Cortisol biosynthesis in the human ocular surface innate immune response.

Cortisol biosynthesis in the human ocular surface innate immune response.

PloS one (2014-04-17)
Radhika Susarla, Lei Liu, Elizabeth A Walker, Iwona J Bujalska, Jawaher Alsalem, Geraint P Williams, Sreekanth Sreekantam, Angela E Taylor, Mohammad Tallouzi, H Susan Southworth, Philip I Murray, Graham R Wallace, Saaeha Rauz

Innate immune responses have a critical role in regulating sight-threatening ocular surface (OcS) inflammation. While glucocorticoids (GCs) are frequently used to limit tissue damage, the role of intracrine GC (cortisol) bioavailability via 11-beta-hydroxysteroid dehydrogenase type 1 (11β-HSD1) in OcS defense, remains unresolved. We found that primary human corneal epithelial cells (PHCEC), fibroblasts (PHKF) and allogeneic macrophages (M1, GM-CSF; M2, M-CSF) were capable of generating cortisol (M1>PHKF>M2>PHCEC) but in corneal cells, this was independent of Toll-like receptor (TLR) activation. While PolyI∶C induced maximal cytokine and chemokine production from both PHCEC (IFNγ, CCL2, CCL3, and (CCL4), IL6, CXCL10, CCL5, TNFα) and PHKF (CCL2, IL-6, CXCL10, CCL5), only PHKF cytokines were inhibited by GCs. Both Poly I∶C and LPS challenged-corneal cells induced M1 chemotaxis (greatest LPS-PHKF (250%), but down-regulated M1 11β-HSD1 activity (30 and 40% respectively). These data were supported by clinical studies demonstrating reduced human tear film cortisol∶cortisone ratios (a biomarker of local 11β-HSD1 activity) in pseudomonas keratitis (1∶2.9) versus healthy controls (1∶1.3; p<0.05). This contrasted with putative TLR3-mediated OcS disease (Stevens-Johnson Syndrome, Mucous membrane pemphigoid) where an increase in cortisol∶cortisone ratio was observed (113.8∶1; p<0.05). In summary, cortisol biosynthesis in human corneal cells is independent of TLR activation and is likely to afford immunoprotection under physiological conditions. Contribution to ocular mucosal innate responses is dependent on the aetiology of immunological challenge.

Product Number
Product Description

Hydrocortisone for peak identification, European Pharmacopoeia (EP) Reference Standard
Epidermal Growth Factor, human, animal component free, EGF, recombinant, expressed in Escherichia coli, >97% (SDS-PAGE)
hEGF, EGF, recombinant, expressed in E. coli, lyophilized powder, suitable for cell culture
Hydrocortisone, γ-irradiated, powder, BioXtra, suitable for cell culture
Hydrocortisone, BioReagent, suitable for cell culture
Hydrocortisone, meets USP testing specifications
Hydrocortisone, ≥98% (HPLC)
Hydrocortisone, Pharmaceutical Secondary Standard; Certified Reference Material
EGF human, Animal-component free, recombinant, expressed in E. coli, ≥98% (SDS-PAGE), ≥98% (HPLC), suitable for cell culture
Hydrocortisone, British Pharmacopoeia (BP) Assay Standard
Hydrocortisone, European Pharmacopoeia (EP) Reference Standard
Hydrocortisone, United States Pharmacopeia (USP) Reference Standard