Dataset Information

TMT-based quantitative proteomic profiling of human monocyte-derived macrophages and foam cells.

ABSTRACT:

Background

Cardiovascular diseases remain the leading cause of morbidity and mortality worldwide, most of which are caused by atherosclerosis. Discerning processes that participate in macrophage-to-foam cell formation are critical for understanding the basic mechanisms underlying atherosclerosis. To explore the molecular mechanisms of foam cell formation, differentially expressed proteins were identified.

Methods

Human peripheral blood mononuclear cells were stimulated with macrophage colony-stimulating factor, and obtained macrophages were transformed into foam cells by oxidized low-density lipoprotein. Tandem mass tag (TMT) labeling combined with mass spectrometry was performed to find associations between foam cell transformation and proteome profiles.

Results

Totally, 5146 quantifiable proteins were identified, among which 1515 and 182 differentially expressed proteins (DEPs) were found in macrophage/monocyte and foam cell/macrophage, respectively. Subcellular localization analysis revealed that downregulated DEPs of macrophages/monocytes were mostly located in the nucleus, whereas upregulated DEPs of foam cells/macrophages were mostly extracellular or located in the plasma membrane. Functional analysis of DEPs demonstrated that cholesterol metabolism-related proteins were upregulated in foam cells, whereas immune response-related proteins were downregulated in foam cells. The protein interaction network showed that the DEPs with the highest interaction scores between macrophages and foam cells were mainly concentrated in lysosomes and the endoplasmic reticulum.

Conclusions

Proteomics analysis suggested that cholesterol metabolism was upregulated, while the immune response was suppressed in foam cells. KEGG enrichment analysis and protein-protein interaction analysis indicated that DEPs located in the endoplasmic reticulum and lysosomes might be key drivers of foam cell formation. These data provide a basis for identifying the potential proteins associated with the molecular mechanism underlying macrophage transformation to foam cells.

SUBMITTER: Zhang Y

PROVIDER: S-EPMC8725474 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background: Cardiovascular diseases remain the leading cause of morbidity and mortality worldwide, most of which are caused by atherosclerosis. Discerning processes that participate in macrophage-to-foam cell formation are critical for understanding the basic mechanisms underlying atherosclerosis. To explore the molecular mechanisms of foam cell formation, the differentially expressed proteins were identified. Methods: In this paper, human monocytes, macrophage colony-stimulating factor induced macrophages, and oxidized low-density lipoprotein induced foam cells were cultured, and tandem mass tag (TMT) labeling combined with mass spectrometry (MS) were performed to find associations between foam cell transformation and proteome profiles. Results: Totally, 5146 quantifiable proteins were identified, among which 1515 and 182 differentially expressed proteins (DEPs) were found in macrophage/monocyte and foam cell/macrophage, respectively, using a cutoff of 1.5-fold change. Subcellular localization analysis revealed that downregulated DEPs of macrophages/monocytes were mostly located in the nucleus and upregulated DEPs of foam cells/macrophages mostly located in the plasma membrane and extracellular. Functional analysis of DEPs demonstrated that cholesterol metabolism related proteins were upregulated in foam cells, whereas the immune response-related proteins were downregulated in foam cells. The protein-interaction network showed that the DEPs with the highest interaction intensity between macrophages and foam cells were mainly concentrated in lysosomes and the endoplasmic reticulum. Conclusions: This study for the first time to perform quantitative proteomic investigation by TMT labeling and LC-MS/MS to identify differentially expressed proteins in human monocyte, macrophage, and foam cell. The results confirmed cholesterol metabolism was upregulated in foam cells, while immune response was suppressed, which suggested that foam cells were not the population that promote inflammation. In addition, KEGG enrichment analysis and protein-protein interaction indicated that the differentially expressed proteins locating in the endoplasmic reticulum and lysosomes may be key targets to regulate foam cell formation. These data provide a basis for identifying the potential proteins associated with the molecular mechanism involved in the transformation of macrophages to foam cells.

Project description:BackgroundHistones and their post-translational modifications impact cellular function by acting as key regulators in the maintenance and remodeling of chromatin, thus affecting transcription regulation either positively (activation) or negatively (repression). In this study we describe a comprehensive, bottom-up proteomics approach to profiling post-translational modifications (acetylation, mono-, di- and tri-methylation, phosphorylation, biotinylation, ubiquitination, citrullination and ADP-ribosylation) in human macrophages, which are primary cells of the innate immune system. As our knowledge expands, it becomes more evident that macrophages are a heterogeneous population with potentially subtle differences in their responses to various stimuli driven by highly complex epigenetic regulatory mechanisms.MethodsTo profile post-translational modifications (PTMs) of histones in macrophages we used two platforms of liquid chromatography and mass spectrometry. One platform was based on Sciex5600 TripleTof and the second one was based on VelosPro Orbitrap Elite ETD mass spectrometers.ResultsWe provide side-by-side comparison of profiling using two mass spectrometric platforms, ion trap and qTOF, coupled with the application of collisional induced and electron transfer dissociation. We show for the first time methylation of a His residue in macrophages and demonstrate differences in histone PTMs between those currently reported for macrophage cell lines and what we identified in primary cells. We have found a relatively low level of histone PTMs in differentiated but resting human primary monocyte derived macrophages.ConclusionsThis study is the first comprehensive profiling of histone PTMs in primary human MDM. Our study implies that epigenetic regulatory mechanisms operative in transformed cell lines and primary cells are overlapping to a limited extent. Our mass spectrometric approach provides groundwork for the investigation of how histone PTMs contribute to epigenetic regulation in primary human macrophages.