Expression of 14-3-3 Zeta Protein in Dexamethasone-Treated Mice and Human TM-1 Cells

ABSTRACT

Purpose: 14-3-3 zeta protein plays a potential protective role in neurodegenerative disease. Given that glaucoma and neurodegenerative diseases share a similar pathogenesis, it is possible that 14-3-3 zeta may have a similar protective effect in the glaucomatous process. In the present study, we measured the expression of 14-3-3 zeta in vivo (mouse eyes) and in vitro in a transformed human trabecular meshwork (HTM) cell line, TM-1, and assessed the possible roles of this protein in dexamethasone (DEX)-treated eyes and HTM cells.

Methods: Mouse eyes were randomly treated with 0.1% dexamethasone (DEX) eye drops or phosphate-buffered solution (PBS) for 28 days. The expression and distribution of 14-3-3 zeta protein in mouse eyes were examined using immunofluorescence. TM-1 cells were treated with DEX (10⁻⁶ or 10⁻⁷ M) or PBS for 1, 4, or 7 days, and the mRNA and protein expression of 14-3-3 zeta were detected by real-time RT-PCR and Western blotting.

Results: 14-3-3 zeta protein was highly expressed in the mouse cornea, trabecular meshwork (TM), and ciliary body. Intraocular pressure (IOP) was significantly elevated, whereas the 14-3-3 zeta expression was significantly decreased in mouse TM after 0.1% DEX treatment for 28 days. In vitro, treatment with 10⁻⁷ M DEX mildly increased 14-3-3 zeta mRNA and protein expression (p > 0.05), whereas 10⁻⁶ M DEX significantly decreased expression of 14-3-3 zeta mRNA and protein (p < 0.05) compared to the control (Ctrl) group at the seventh day.

Conclusions: DEX can increase IOP in mouse eyes and concurrently downregulate 14-3-3 zeta protein expression in mouse TM. The effects of DEX on 14-3-3 zeta expression in vitro were both dose- and time-related. Our results suggest that alterations in 14-3-3 zeta protein may be implicated in DEX-induced pathological elevated IOP.

KEYWORDS:

• Dexamethasone
• intraocular pressure
• mouse
• trabecular meshwork cells
• 14-3-3 zeta

Declaration of interest

The authors report no conflict of interests.

Funding

This work was supported by grants from the National Natural Science Foundation of China (81170848, 81200685, U1404812) and The State Key Laboratory Program of Ophthalmology for Young Scholars (NO. 2014QN06).

Additional information

Funding

This work was supported by grants from the National Natural Science Foundation of China (81170848, 81200685, U1404812) and The State Key Laboratory Program of Ophthalmology for Young Scholars (NO. 2014QN06).