Progranulin expression in advanced human atherosclerotic plaque

Area of Science:

• Molecular biology
• Immunology
• Cardiovascular research

Background:

• Progranulin (PGRN) is a growth factor crucial for wound healing with anti-inflammatory properties.
• Degradation of PGRN into granulin peptides (GRNs) by neutrophil proteases triggers pro-inflammatory responses.
• Atherosclerosis involves injury, inflammation, and repair, suggesting a role for PGRN in its development.

Purpose of the Study:

• To investigate the role of Progranulin (PGRN) in the context of atherosclerosis.
• To determine the effects of PGRN and its degradation products (GRNs) on vascular cells and inflammatory markers.

Main Methods:

• Immunohistochemical analysis of human carotid endarterectomy specimens.
• Assessing the impact of PGRN on human monocytic leukemia (THP-1) and aortic smooth muscle cells (HASMCs) proliferation and migration.
• Evaluating cytokine secretion (IL-8) and cellular responses to PGRN, GRNs, MCP-1, and TNF-alpha.

Main Results:

• PGRN was expressed by vascular smooth muscle cells and macrophages in atherosclerotic plaques.
• PGRN inhibited MCP-1-induced THP-1 cell migration and reduced IL-8 secretion from HASMCs.
• Degraded GRNs increased IL-8 secretion, while exogenous PGRN decreased it, indicating opposing effects.

Conclusions:

• PGRN expression primarily exerts anti-inflammatory effects within atherosclerotic plaques.
• The degradation of PGRN into GRNs promotes inflammation, potentially contributing to atherosclerosis progression.
• Targeting PGRN or its degradation products may offer therapeutic strategies for atherosclerosis.