Modulation of factors affecting optic nerve head astrocyte migration.

Area of Science:

• Ophthalmology
• Cell Biology
• Molecular Biology

Background:

• Optic nerve head (ONH) astrocyte migration is implicated in glaucoma pathogenesis.
• Myosin light chain kinase (MYLK) and transforming growth factor beta (TGFbeta) signaling pathways are critical regulators of cell migration.

Purpose of the Study:

• To investigate the roles of MYLK and TGFbeta receptor pathways in ONH astrocyte migration.
• To determine how elevated hydrostatic pressure (HP) affects the expression of MYLK and TGFbeta pathway components in ONH astrocytes.

Main Methods:

• Polymerase chain reaction (PCR) was used to identify MYLK isoforms in ONH astrocytes.
• Small interfering RNAs (siRNAs) targeting MYLK and TGFbeta receptor 2 (TGFBR2) were employed to assess their impact on astrocyte migration.
• The effects of elevated HP on MYLK isoform and TGFbeta pathway component expression were quantified.

Main Results:

• ONH astrocytes express multiple MYLK isoforms (MYLK-130, MYLK-210, and a splicing variant).
• MYLK and TGFBR2 inhibition reduced astrocyte migration and TGFbeta-regulated gene expression.
• Elevated HP increased MYLK expression in both Caucasian and African American astrocytes, while TGFbeta2 was uniquely upregulated in Caucasian astrocytes.

Conclusions:

• The differential expression of MYLK and TGFbeta pathway genes under elevated HP mirrors findings in glaucomatous astrocytes.
• MYLK represents a potential therapeutic target for modulating ONH astrocyte migration in glaucoma.