Label-free quantitative proteomic analysis of serum exosomes in mice with thoracic aortic aneurysm.

Objective: Thoracic aortic aneurysm (TAA) is a cardiovascular disease with high morbidity and mortality. However, the causes and mechanisms of TAA are not fully understood. Serum exosomes from mice with TAA were used to explore the markers associated with this disease.

Methods: C57BL/6 mice were divided into three groups and given ordinary drinking water, ordinary drinking water plus a saline osmotic pump, or drinking water containing β-aminopropionitrile (BAPN) (1 g/kg/d) plus an angiotensin II (Ang II) (1 μg/kg/min) osmotic pump. Haematoxylin and eosin staining of thoracic aortic tissues was performed. The basic characteristics of exosomes were analysed. Differentially expressed proteins (DEPs) were identified by LC‒MS/MS. Protein‒protein networks and enrichment analysis were used to explore possible molecular mechanisms.

Results: The present study elucidated the protein expression profile of serum exosomes in mice with TAA induced by BAPN combined with Ang II. In this work, the expression of a total of 196 proteins was significantly dysregulated in serum exosomes of mice with TAA, with 122 proteins significantly upregulated and 74 proteins markedly downregulated. Notably, Haptoglobin (Hp) and Serum amyloid p-component (Sap) identified based on the PPI network were significantly upregulated and have been strongly linked to cardiovascular disease. Interestingly, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the upregulated and downregulated proteins were involved in the complement and coagulation cascade pathways.

Conclusions: This study showed that the identified DEPs have potential as biomarkers for the diagnosis of TAA and provided a more comprehensive understanding of the pathophysiological mechanisms of TAA.