School of Clinical Medicine, Tsinghua University.
Department of Cardiology, Beijing Tsinghua Changgung Hospital, School of Clinical Medicine, Tsinghua University.
Int Heart J. 2022;63(3):566-577. doi: 10.1536/ihj.21-354.
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.
端粒长度与心血管疾病高度相关。端粒锌指相关蛋白（TZAP）通过锌指结构域直接与端粒 TTAGGG 重复序列结合，并触发端粒修剪过程的启动。然而，心肌细胞中 TZAP 的蛋白质组学分析还知之甚少。在我们的研究中，通过腺病毒转染在培养的 H9c2 心肌细胞中过表达 TZAP，然后进行基于质谱的定量蛋白质组学研究策略，包括基因本体分析、京都基因与基因组百科全书（KEGG）通路分析、亚细胞定位、预测功能域和蛋白质-蛋白质相互作用（PPI）分析，以探讨 TZAP 诱导心肌细胞潜在发病机制。在 TZAP 过表达的心肌细胞中，在鉴定的 5693 个可定量蛋白质中，共鉴定出 184 个上调和 228 个下调的差异表达蛋白（DEPs）。这些 DEPs 主要分布在核、细胞质和质膜中。DEPs 富集于包括心肌细胞收缩、急性炎症反应、细胞-细胞连接组装和大分子生物合成过程在内的生物学过程中。它们在包括 Hippo 信号通路、蛋白质消化和吸收以及细胞因子受体相互作用在内的 9 个 KEGG 通路中富集，并在 17 个蛋白质域中富集，包括翻译起始因子 1A/IF-1、I 类组织相容性抗原和锌指。PPI 分析表明，TZAP 与 NDUFC2、Gja1 和 HDAC2 相互作用。此外，作为与心血管功能密切相关的蛋白质，BRD4、Gja1、HDAC2、MAP2K3、Plakophilin 4 和 Syndecan 1 的 mRNA 水平在 TZAP 过表达的心肌细胞中显著降低，而 RT-PCR 检测显示 Trpm7、clusterin 和 NDUFC2 显著增加，与蛋白质组学分析一致。总之，我们提供了 TZAP 过表达心肌细胞中的候选蛋白和富集途径，这些需要进一步研究。
