Mass Spectrometry-Based Quantitative Proteomics Analysis for Better Understanding of Telomeric Zinc Finger-Associated...

Telomere length is highly related to cardiovascular diseases. Telomeric zinc finger-associated protein (TZAP) directly binds to telomeric TTAGGG repeats via zinc finger domains and triggers the initiation of the telomere trimming process. However, proteomics analysis of TZAP in cardiomyocytes is slightly unknown. In our study, TZAP was overexpressed by adenovirus transfection in cultured H9c2 cardiomyocytes, and then mass spectrometry-based quantitative proteomics research strategies, including Gene Ontology analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, subcellular localizations, predicted functional domains, and protein-protein interaction (PPI) analysis, were performed to explore TZAP-induced potential pathogenesis in cardiomyocytes. A total of 184 upregulated and 228 downregulated differentially expressed proteins (DEPs) were identified among identified 5693 quantifiable proteins in TZAP-overexpressed cardiomyocytes. These DEPs were mainly distributed in the nucleus, cytoplasm, and plasma membrane. DEPs were enriched in biological processes including cardiac muscle cell contraction, acute inflammatory response, cell-cell junction assembly, and macromolecule biosynthetic process. They were enriched in 9 KEGG pathways, including Hippo signaling pathway, protein digestion and absorption, and cytokine receptor interaction, and enriched in 17 protein domains, including translation initiation factor 1A/IF-1, class I histocompatibility antigen, and zinc finger. PPI analysis indicated that TZAP interacted with NDUFC2, Gja1, and HDAC2. Further, as proteins closely related to cardiovascular function, the mRNA levels of BRD4, Gja1, HDAC2, MAP2K3, Plakophilin 4, and Syndecan 1 significantly decreased, while Trpm7, clusterin, and NDUFC2 remarkably increased in TZAP-overexpressed cardiomyocytes by RT-PCR assay, which were consistent with the proteomics analysis. Collectively, we provided candidate proteins and enrichment pathways in TZAP-overexpressed cardiomyocytes, which need further investigation.