Gadecka Agnieszka, Koblowska Marta, Kossowska Helena, Iwanicka-Nowicka Roksana, Janiszewska Dorota, Mosieniak Grażyna, Bojakowski Krzysztof, Goryca Krzysztof, Bielak-Zmijewska Anna
Laboratory of Molecular Basis of Aging, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., Warsaw, 02-093, Poland.
Laboratory of Systems Biology, Faculty of Biology, University of Warsaw, 1 Miecznikowa St., Warsaw, 02-096, Poland.
Cell Commun Signal. 2025 Jul 1;23(1):321. doi: 10.1186/s12964-025-02315-8.
Cellular senescence is a fundamental process leading to organismal aging and age-related diseases. Alterations accompanying cellular senescence concern, among others, nucleus architecture, chromatin structure, DNA damage and gene expression. Some changes are universal for all types of senescence, but some characteristics are typical for a given senescence inductor or cell type. The aim of the study was to analyze senescence-associated alterations in chromatin modifications and look for differences depending on senescence type (replicative, RS and stress-induced premature senescence, SIPS) in vascular smooth muscle cells (VSMCs) in vitro. The alterations were compared with those observed in VSMCs derived from atherosclerotic plaques (ex vivo) and, to assess their universality, with those in senescent fibroblasts.
We investigated the level and distribution of HP1α and H3 modifications that are markers of hetero- and euchromatin (H3K9me3, H3K27me3, H3K4me3, H3K9Ac - WB and IF), alterations in the transcriptomic profile (DNA microarray, qPCR), H3K4me3, H3K9me3 and HP1α protein distribution in the genome (ChIP-seq), and expression of enzymes involved in histone post-translational modifications (DNA microarray, qPCR, WB, IF).
Our results have shown that the decline in H3K4me3 and H3K9me3 modifications and in HP1α is a universal hallmark of senescence in all tested cell and senescence types, although the extent of the change depends on the senescence inductor. The distribution of H3K4me3 and H3K9me3 in the genome of VSMCs depends on the senescence type, and the transcriptomic analysis identified genes and processes specific to each type.
We characterized senescence and cell type-dependent changes in chromatin-associated proteins and enzymes involved in histone H3 decoration which, in consequence, impact senescence-associated gene expression. We can conclude that certain similar alterations occur in senescent VSMCs ex vivo, although inter-individual differences usually obscure them. Our results clearly showed that differences existed not only between young and senescent cells but also between SIPS and RS ones. The subtle differences between various SIPS types suggest that various stressors activate the same cellular mechanisms. This study can serve as a starting point to search for factors that may be used to distinguish between SIPS and RS, which in turn could be helpful in defining conditions responsible for accelerated aging.
细胞衰老乃是导致机体衰老及与年龄相关疾病的基本过程。伴随细胞衰老出现的改变包括细胞核结构、染色质结构、DNA损伤以及基因表达等。某些改变对于所有类型的衰老而言具有普遍性，但有些特征则是特定衰老诱导因素或细胞类型所特有的。本研究旨在分析体外培养的血管平滑肌细胞（VSMC）中衰老相关的染色质修饰改变，并探寻依据衰老类型（复制性衰老，RS；应激诱导的早衰，SIPS）而存在的差异。将这些改变与源自动脉粥样硬化斑块的VSMC（体外）所观察到的改变进行比较，并且为评估其普遍性，还与衰老成纤维细胞中的改变进行比较。
我们研究了作为异染色质和常染色质标志物的HP1α和H3修饰的水平及分布（H3K9me3、H3K27me3、H3K4me3、H3K9Ac - 蛋白质免疫印迹和免疫荧光）、转录组图谱的改变（DNA微阵列、定量聚合酶链反应）、基因组中H3K4me3、H3K9me3和HP1α蛋白的分布（染色质免疫沉淀测序）以及参与组蛋白翻译后修饰的酶的表达（DNA微阵列、定量聚合酶链反应、蛋白质免疫印迹、免疫荧光）。
我们的结果表明，H3K4me3、H3K9me3修饰以及HP1α的下降是所有测试细胞和衰老类型中衰老的普遍标志，尽管变化程度取决于衰老诱导因素。VSMC基因组中H3K4me3和H3K9me3的分布取决于衰老类型，并且转录组分析确定了每种类型所特有的基因和过程。
我们描述了衰老以及与染色质相关的蛋白质和参与组蛋白H3修饰的酶的细胞类型依赖性变化，这些变化进而影响衰老相关的基因表达。我们可以得出结论，在体外衰老的VSMC中会出现某些相似的改变，尽管个体差异通常会使其变得模糊不清。我们的结果清楚地表明，差异不仅存在于年轻细胞与衰老细胞之间，也存在于SIPS细胞与RS细胞之间。不同类型SIPS之间的细微差异表明，各种应激源激活了相同的细胞机制。本研究可作为寻找可用于区分SIPS和RS的因素的起点，这反过来可能有助于确定导致加速衰老的条件。
