Protein carbamylation exacerbates vascular calcification.

Area of Science:

• Biochemistry
• Pathology
• Vascular Biology

Background:

• Protein carbamylation, a non-enzymatic modification, is linked to urea accumulation.
• While a prognostic biomarker, its role in organ dysfunction, particularly vascular calcification, is unclear.

Purpose of the Study:

• To investigate the impact of protein carbamylation on vascular calcification.
• To elucidate the underlying molecular mechanisms involving ENPP1 and mitochondrial function.

Main Methods:

• Human vascular smooth muscle cells (hVSMCs) were used to study carbamylation effects.
• ENPP1 expression, mitochondrial membrane potential, and oxidative stress were assessed.
• Experiments included ENPP1 knockdown, mitochondrial DNA depletion, and use of superoxide scavengers.
• Ex vivo and in vivo models, including end-stage renal disease patient samples, were utilized.

Main Results:

• Protein carbamylation exacerbated hVSMC calcification by suppressing ENPP1 expression.
• Carbamylation reduced mitochondrial membrane potential and increased oxidative stress, leading to ENPP1 downregulation.
• These effects were dependent on mitochondrial function and ENPP1 activity.
• Carbamylated tunica media was observed in an end-stage renal disease patient.

Conclusions:

• Protein carbamylation promotes vascular calcification via mitochondrial dysfunction and subsequent ENPP1 suppression.
• This study uncovers a novel mechanism in uremia-associated vascular pathology.
• Targeting carbamylation or mitochondrial pathways may offer therapeutic strategies for vascular complications.