Identifying vascular stiffening-sensitive macrophages through integration of single-cell transcriptomics and imaging...

Area of Science:

• Cardiovascular Biology
• Immunology
• Biomaterials Science

Background:

• Increased extracellular matrix (ECM) stiffness is a key risk factor in cardiovascular disease (CVD).
• Arterial stiffness is associated with inflammation and immune cell infiltration in the vessel wall.
• Specific immune cells and factors responding to arterial stiffness remain largely unknown.

Purpose of the Study:

• To identify immune cell populations sensitive to mechanical stress in stiffened arteries.
• To investigate the role of specific macrophage populations in response to extracellular matrix stiffness.
• To explore SPP1 as a potential biomarker for arterial stiffening.

Main Methods:

• Single-cell RNA sequencing (scRNA-seq) of immune cells in stiffened carotid plaques.
• In vitro studies using polyacrylamide gels of varying stiffness to model arterial stiffening.
• In vivo mouse model of acute calcification to replicate arterial stiffening.
• Imaging flow cytometry to analyze cell populations and gene expression in response to ECM stiffness.

Main Results:

• scRNA-seq identified SPP1high macrophages as a prominent myeloid population influencing ECM composition.
• Macrophages cultured on stiffer matrices showed elevated SPP1 protein levels.
• The percentage of SPP1high macrophages increased in stiffened arterial walls in a mouse model of vascular calcification.

Conclusions:

• SPP1high macrophages are sensitive to extracellular matrix stiffness.
• Macrophage-derived SPP1 may serve as a potential biomarker for arterial stiffening in cardiovascular disease.
• This study provides insights into immune cell responses to mechanical stress in atherosclerosis.