Silencing KRIT1 Partially Reverses the Effects of Disturbed Flow on the Endothelial Cell Transcriptome

Area of Science:

• Endothelial cell biology
• Molecular mechanisms of atherosclerosis
• Transcriptomics and gene regulation

Background:

• Endothelial cells regulate vascular health through responses to blood flow shear stress, primarily mediated by Krüppel-like factors 2 and 4 (KLF2 and KLF4).
• Disturbed blood flow, associated with atherosclerosis, reduces KLF2 and KLF4 expression, promoting inflammation and thrombosis.
• The endothelial Cell-Cell Molecule (CCM) complex, including KRIT1, normally suppresses KLF2 and KLF4; its loss of function may protect against atherosclerosis.

Purpose of the Study:

• To investigate whether silencing KRIT1, a key component of the CCM complex, can normalize the detrimental effects of disturbed blood flow on the human endothelial transcriptome.
• To determine if KRIT1 silencing can restore atheroprotective gene expression patterns in endothelial cells exposed to disturbed flow.

Main Methods:

• Human umbilical vein endothelial cells (HUVECs) underwent KRIT1 gene silencing using small interfering RNAs (siRNAs).
• Cells were subjected to distinct flow conditions: laminar (pulsatile shear stress), disturbed (oscillatory shear stress), and static (no flow) for 24 hours.
• Bulk RNA sequencing (RNA-seq) was performed to analyze transcriptomic changes.

Main Results:

• Silencing KRIT1 in HUVECs successfully restored the expression of KLF2 and KLF4 under oscillatory shear stress conditions.
• The transcriptomic profile of KRIT1-silenced cells under disturbed flow closely resembled that of cells under normal laminar flow.
• These results indicate that inhibiting the CCM complex reactivates a vasoprotective gene program in endothelial cells.

Conclusions:

• Inhibition of the CCM complex, specifically KRIT1, confers vasoprotection by enhancing endothelial resilience to disturbed blood flow.
• Targeting CCM genes can activate protective pathways, offering a novel therapeutic strategy for preventing atherosclerosis.
• This approach promotes endothelial resistance to inflammation, hypoxia, and supports angiogenesis under atherogenic conditions.