Cigarette smoke condensate affects monocyte interaction with endothelium

Area of Science:

• Cardiovascular Biology
• Immunology
• Atherosclerosis Research

Background:

• Monocyte adhesion and transmigration into the endothelium are key processes in atherosclerotic plaque development.
• Cigarette smoke is a known risk factor for atherosclerosis, but its precise impact on monocyte-endothelial interactions is not fully understood.

Purpose of the Study:

• To investigate the effects of cigarette smoke condensate (CSC) on human monocyte (HM) chemotaxis and transmigration across endothelial cells (ECs).
• To elucidate the molecular mechanisms underlying CSC's influence on monocyte behavior and endothelial interactions in atherogenesis.

Main Methods:

• Assessed human monocyte (HM) chemotaxis and transmigration through endothelial cell (EC) monolayers using cigarette smoke condensate (CSC).
• Analyzed the expression of key molecules including Rac 1 GTPase, VCAM1, ICAM1, integrins, TLR4, MCP1, IL8, IL1beta, and TNFalfa.
• Utilized conditioned media from CSC-exposed HMs and neutralizing antibodies for mechanistic studies.

Main Results:

• CSC pre-treatment reduced HM chemotaxis and transmigration, linked to decreased Rac 1 GTPase expression.
• Direct CSC exposure increased HM transmigration, stimulating EC VCAM1/ICAM1 and monocyte integrin expression.
• CSC-conditioned medium significantly enhanced HM transmigration, mediated by HM-released factors like MCP1 and IL8, and increased expression of TLR4, IL1beta, and TNFalfa.

Conclusions:

• CSC exerts dual effects: it can impair monocyte migratory capacity but also induces HMs to release factors that amplify inflammatory cell recruitment and transmigration.
• These complex interactions between CSC, monocytes, and endothelium can exacerbate the atherosclerotic process.