Mitochondrial ROS in Slc4a11 KO Corneal Endothelial Cells Lead to ER Stress

Area of Science:

• Cell Biology
• Ophthalmology
• Mitochondrial Biology

Background:

• Congenital Hereditary Endothelial Dystrophy (CHED) involves corneal endothelial cell dysfunction.
• Previous studies link glutamine metabolism to mitochondrial dysfunction and cell death in CHED models.
• Lysosomes originate from the endoplasmic reticulum (ER)-Golgi pathway, suggesting a potential link between mitochondrial and ER function.

Purpose of the Study:

• To investigate if mitochondrial reactive oxygen species (ROS) impact endoplasmic reticulum (ER) function in Slc4a11 knockout (KO) corneal endothelial cells.
• To determine the role of ER stress in CHED pathogenesis.

Main Methods:

• Analysis of ER morphology and expression of ER stress markers (BIP, CHOP) in Slc4a11 KO mouse corneal endothelium.
• Incubation of Slc4a11 KO corneal endothelial cells with glutamine and assessment of aggresome formation, ER stress markers, and ER Ca2+ release.
• Induction of mitochondrial ROS (mitoROS) in wild-type (WT) cells via electron transport chain (ETC) inhibition.
• Treatment of Slc4a11 KO cells with MitoQ, a mitochondrial ROS scavenger, both in vitro and systemically in mice.

Main Results:

• Slc4a11 KO corneal endothelium exhibited ER dilation and elevated BIP and CHOP expression.
• Glutamine-treated Slc4a11 KO cells showed increased aggresomes, BIP/GADD153, and reduced ER Ca2+ release compared to WT.
• ETC inhibition induced ER stress in WT cells.
• MitoQ treatment restored ER Ca2+ release and alleviated ER stress markers in Slc4a11 KO cells, with systemic MitoQ reducing BIP expression.

Conclusions:

• Mitochondrial ROS contribute to endoplasmic reticulum (ER) stress in corneal endothelial cells.
• ER stress is a key mechanism linking mitochondrial dysfunction to cell pathology in CHED models.
• Targeting mitochondrial ROS may offer a therapeutic strategy for CHED.