Transient High-Glucose Exposure and Erk Signaling.

Area of Science:

• Cardiovascular Biology
• Molecular Cell Biology
• Endothelial Cell Function

Background:

• Transient high-glucose exposure is known to induce Erk2 phosphorylation and proliferation in human coronary artery endothelial cells (HCAEC).
• The precise upstream molecular mechanisms driving this response in HCAEC remain largely unelucidated.

Purpose of the Study:

• To investigate the signaling pathways mediating Erk2 activation in HCAEC following transient high-glucose exposure.
• To identify key molecular players involved in the response of HCAEC to hyperglycemia.

Main Methods:

• Human coronary artery endothelial cells (HCAEC) were subjected to transient exposure (1 hour) of high D-glucose (183 mg/dL) followed by a period in glucose-free medium.
• Analysis included assessment of microRNA-138 (miR-138) levels, Giα2 protein expression, and the activity of Rap1 and Ras signaling proteins.

Main Results:

• Transient high D-glucose significantly decreased miR-138 levels in HCAEC.
• This was accompanied by an increase in Giα2 protein levels.
• The signaling cascade involved inactivation of Rap1 and activation of Ras, ultimately leading to Erk2 activation.

Conclusions:

• Transient high D-glucose activates Erk2 in HCAEC through a specific signaling axis involving miR-138, Giα2, Rap1, and Ras.
• This miRNA-138/Giα2/Rap1/Ras pathway represents a potential therapeutic target for managing conditions like atherosclerosis.