Metadata language
Instytut Biologii Doświadczalnej im. Marcelego Nenckiego PAN
Contributor:Mosieniak, Grażyna : Supervisor
Publisher:Instytut Biologii Doświadczalnej im. Marcelego Nenckiego PAN
Place of publishing: Date issued/created: Description:196 pages : illustrations ; 30 cm ; Bibliography ; Summary in English
Degree name: Degree discipline : Degree grantor:Nencki Institute of Experimental Biology PAS ; degree obtained: 23.02.2024
Type of object: Subject and Keywords:Atherosclerosis ; Cellular senescence ; Extracellular vesicles ; T lymphocytes ; Vascular smooth muscle cells
Abstract:
Cellular senescence is a process that significantly impacts the functioning of the whole organism. It is characterized by a stable and irreversible cell cycle arrest, while maintaining its metabolic activity. During this multi-stage process, a number of changes occur within the cell, which leads to the senescent cell achieving a specific phenotype. Along with new research on cellular senescence, awareness of the complexity and diversity of this process, which depends e.g. on the cell type or the inducing factor, is growing. One of the most important features of senescent cells that have the greatest physiological significance is senescence-associated secretory phenotype (SASP). Recently published data suggest that extracellular vesicles (EVs) may play an important and so far little-understood role in the complex and diverse functions of SASP. It has been proven that SASP may contribute to chronic inflammation, which promotes age-related diseases, such as atherosclerosis. The studies published so far have demonstrated the presence of senescent vascular smooth muscle cells (VSMC) within the atherosclerotic plaque, where they play an important role in its development. Moreover, SASP factors secreted by senescent cells can influence neighboring cells, including T lymphocytes, and modify the tissue microenvironment, thereby contributing to the promotion of inflammation. In the first part of this dissertation, I characterized and compared the premature senescence phenotype in three different types of normal cells cultured in vitro and induced to senescence by doxorubicin or hydrogen peroxide treatment. Changes in the phenotype of senescent cells were compared with the phenotype of proliferating cells and quiescent cells with temporary inhibited proliferation. I showed that the changes which correlated the most strongly with senescence were a decreased level of nuclear proteins - lamin B1, HMGB1, PARP1 and a decreased level of a protein involved in the regulation of mitosis - cyclin B1. These changes can be considered as universal markers of senescence. Next, I compared the replicative and premature senescence of VSMC at the early and late stages of this process. I have shown that the changes observed at the early stage intensify over the time after the inhibition of proliferation. I observed an increased activity of SA-β-gal, a decreased level of HMGB1 and lamin B1 proteins, an increased level of p16 protein and an increased amount of secreted cytokines. Based on the obtained results, I concluded that the phenotype of cells in the late state of senescence differs from that in the early state and is resemble the phenotype of cells undergoing replicative senescence. I also analyzed selected markers in smooth muscle cells isolated from atherosclerotic plaques as an in vivo model of senescence. I observed a decrease level of proteins that I identified, based on previous analyses, as universal markers of senescence. Moreover, cells undergoing senescence in vivo were characterized by increased secretion of SASP factors, and the secretory profile of smooth muscle cells isolated from atherosclerotic plaques was largely similar to the secretory profile of cells undergoing replicative senescence and premature senescence at a late state of this process. I characterized extracellular vesicles (EVs) secreted by VSMC cells. I have shown that VSMC undergoing replicative and premature senescence secrete significantly more EVs than control one. Based on the proteomic analysis of EVs and soluble factors, I showed differences in the composition of the secretome of control and senescent cells, as well as the secretome of cells undergoing replicative and premature senescence. I examined the influence of factors secreted by senescent VSMC on the activation, proliferation and migration of T lymphocytes and on the secretion of cytokines by these cells.
Copyright-protected material. May be used within the limits of statutory user freedoms
Copyright holder:Publication made available with the written permission of the author
Digitizing institution:Nencki Institute of Experimental Biology of the Polish Academy of Sciences
Original in:Library of the Nencki Institute of Experimental Biology PAS
Access: