Ocular surface epithelial cells up-regulate HLA-G when expanded in vitro on amniotic membrane substrates

Area of Science:

• Ophthalmology
• Immunology
• Cell Biology

Background:

• The ocular surface relies on epithelial cells for immune regulation.
• Amniotic membrane (AM) is used in ocular surface transplantation for its therapeutic properties.
• Understanding immunomodulatory gene expression in these cells is crucial for optimizing transplantation outcomes.

Purpose of the Study:

• To investigate the modulation of immunoregulatory genes in ocular surface epithelial cells cultured on amniotic membrane (AM).
• To identify specific immunoregulatory genes, such as HLA-G, that are affected by AM culture.

Main Methods:

• Conjunctival epithelial cell line (CCL20.2) and primary limbal (LE) and conjunctival epithelial (CE) cells were cultured on AM and collagen.
• Microarray analysis and RT-PCR were used to assess gene expression.
• Immunocytochemistry and Western blot analysis confirmed protein expression.
• Functional assays evaluated the impact of HLA-G on natural killer (NK) cell activity.

Main Results:

• HLA-G (fetal nonclassic major histocompatibility complex molecule) was the primary immunoregulatory gene upregulated by AM.
• Both LE and CE cells showed increased HLA-G protein expression when cultured on AM.
• HLA-G mRNA levels were significantly higher in CE cells cultured on AM compared to collagen.
• Transfection with LE-derived HLA-G mRNA slightly reduced NK cell-induced lysis of target cells.

Conclusions:

• Conjunctival and limbal epithelial cells express functional HLA-G when expanded ex vivo on AM.
• Upregulation of HLA-G may play a role in modulating inflammation and immune reactions following ocular surface transplantation.