Single-Cell Proteomics Reveals Novel Cell Phenotypes in Marfan Mouse Aneurysm

Area of Science:

• Proteomics
• Genomics
• Cardiovascular Biology
• Mass Spectrometry

Background:

• Complex tissues contain diverse cell types crucial for organ function.
• Understanding cell-type-specific molecular differences is vital for disease research.
• Marfan syndrome is a genetic disorder affecting connective tissue, often leading to aortic aneurysms.

Purpose of the Study:

• To apply single-cell proteomic mass spectrometry (SCP-MS) to profile cells from mammalian aorta.
• To investigate differences in cell types and protein expression in Marfan syndrome models.
• To compare proteomic data with existing single-cell RNA sequencing data.

Main Methods:

• Direct label-free mass spectrometry was used for single-cell proteomic analysis (SCP-MS).
• The nanoDTSC approach profiled individual cells from wild-type and Fbn1^C1041G/+ Marfan mice aortas.
• Leiden clustering identified major aortic cell types, including seven smooth muscle cell (SMC) subtypes.

Main Results:

• SCP-MS identified major aortic cell types and revealed differences in cell proportions and protein expression based on genotype and sex.
• Comparisons with single-cell RNA data showed agreement in major subtype detection but not in differentiating SMC subtypes.
• Integrated multi-omics analysis highlighted genotype-dependent enrichment of unique SMC subtypes.
• Spatial proteomics validated key genotype markers.

Conclusions:

• SCP-MS is a powerful tool for detecting novel biology in complex tissues, such as aneurysm development.
• This study provides a methodological guide for applying SCP-MS to complex cell mixtures.
• Integrating SCP-MS with other omics modalities enhances biological discovery.