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The Silk‐protein Sericin Induces Rapid Melanization of Cultured Retinal Pigment Epithelial Cells by Activating the NF ‐ κ B Pathway
Author(s) -
Pasovic L.,
Utheim T.P.,
Reppe S.,
Lyberg T.,
Olstad O.K.,
Eidet J.R.
Publication year - 2015
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2015.0482
Subject(s) - sericin , rpe65 , microbiology and biotechnology , cell culture , retinal pigment epithelium , autophagy , nf κb , silk , biology , chemistry , apoptosis , retinal , signal transduction , biochemistry , genetics , materials science , composite material
Purpose Restoration of the retinal pigment epithelial ( RPE ) cells to prevent further loss of vision in patients suffering from age‐related macular degeneration represents one of the most promising novel treatment modalities in regenerative medicine. Development of RPE transplants in the laboratory, however, is a lengthy process requiring up to 3 months of cell differentiation. We explored whether the silk protein sericin can be used as a culture medium supplement to induce differentiation of human RPE . Methods Microarray analysis determined the expression of RPE ‐associated transcripts in control cultures and cultures supplemented with sericin. Quantitative immunofluorescence ( QIM ), spectrophotometry and transmission electron microscopy ( TEM ) validated the findings. Results Sericin supplementation increased the expression of RPE ‐associated transcripts ( RPE 65 and CRALBP ). The NF ‐kB pathway was identified as one of the top sericin‐induced regulators. Increased levels of RPE ‐associated proteins (including CRALB and the pigment melanin) in the sericin‐supplemented cultures were confirmed by QIM , spectrophotometry and TEM . Sericin supplementation also increased cell survival following serum starvation. Inclusion of NF ‐kB agonists and antagonists in the culture medium showed that activation of the NF ‐kB pathway appears to be necessary, but not sufficient, for sericin‐induced RPE pigmentation. Conclusions Sericin promotes pigmentation of cultured human RPE by activating the NF ‐kB pathway.