Stachecka Joanna, Walczak Agnieszka, Kociucka Beata, Ruszczycki Błażej, Wilczyński Grzegorz, Szczerbal Izabela
Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wolynska 33, 60-637, Poznan, Poland.
Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614, Poznan, Poland.
Histochem Cell Biol. 2018 Feb;149(2):113-126. doi: 10.1007/s00418-017-1618-9. Epub 2017 Nov 13.
Differentiation of progenitor cells into adipocytes is accompanied by remarkable changes in cell morphology, cytoskeletal organization, and gene expression profile. Mature adipocytes are filled with a large lipid droplet and the nucleus tends to move to the cell periphery. It was hypothesized that the differentiation process is also associated with changes of nuclear organization. The aim of this study was to determine the number and distribution of selected components of nuclear architecture during porcine in vitro adipogenesis. The pig is an important animal model sharing many similarities to humans at the anatomical, physiological, and genetic levels and has been recognized as a good model for human obesity. Thus, understanding how cellular structures important for fundamental nuclear processes may be altered during adipocyte differentiation is of great importance. Mesenchymal stem cells (MSCs) were derived from bone marrow (BM-MSCs) and adipose tissue (AD-MSCs) and were cultured for 7 days in the adipogenic medium. A variable differentiation potential of these cell populations towards adipogenic lineage was observed, and for further study, a comparative characteristic of the nuclear organization in BM-MSCs and AD-MSCs was performed. Nuclear substructures were visualized by indirect immunofluorescence (nucleoli, nuclear speckles, PML bodies, lamins, and HP1α) or fluorescence in situ hybridization (telomeres) on fixed cells at 0, 3, 5, and 7 days of differentiation. Comprehensive characterization of these structures, in terms of their number, size, dynamics, and arrangement in three-dimensional space of the nucleus, was performed. It was found that during differentiation of porcine MSCs into adipocytes, changes of nuclear organization occurred and concerned: (1) the nuclear size and shape; (2) reduced lamin A/C expression; and (3) reorganization of chromocenters. Other elements of nuclear architecture such as nucleoli, SC-35 nuclear speckles, and telomeres showed no significant changes when compared to undifferentiated and mature fat cells. In addition, the presence of a low number of PML bodies was characteristic of the studied porcine mesenchymal stem cell adipogenesis system. It has been shown that the arrangement of selected components of nuclear architecture was very similar in MSCs derived from different sources, whereas adipocyte differentiation involves nuclear reorganization. This study adds new data on nuclear organization during adipogenesis using the pig as a model organism.
祖细胞向脂肪细胞的分化伴随着细胞形态、细胞骨架组织和基因表达谱的显著变化。成熟脂肪细胞充满了一个大的脂滴，细胞核倾向于移向细胞周边。据推测，分化过程也与核组织的变化有关。本研究的目的是确定猪体外脂肪生成过程中核结构选定成分的数量和分布。猪是一种重要的动物模型，在解剖、生理和遗传水平上与人类有许多相似之处，并且已被公认为人类肥胖的良好模型。因此，了解在脂肪细胞分化过程中对基本核过程重要的细胞结构是如何改变的非常重要。间充质干细胞（MSCs）来源于骨髓（BM-MSCs）和脂肪组织（AD-MSCs），并在成脂培养基中培养7天。观察到这些细胞群体向脂肪生成谱系的分化潜能各不相同，为进一步研究，对BM-MSCs和AD-MSCs中的核组织进行了比较特征分析。在分化的0、3、5和7天，通过间接免疫荧光（核仁、核斑点、PML小体、核纤层蛋白和HP1α）或荧光原位杂交（端粒）对固定细胞中的核亚结构进行可视化。对这些结构的数量、大小、动态以及在细胞核三维空间中的排列进行了全面表征。研究发现，在猪MSCs向脂肪细胞分化过程中，发生了核组织的变化，涉及：（1）核大小和形状；（2）核纤层蛋白A/C表达降低；（3）染色中心的重组。与未分化和成熟脂肪细胞相比，核结构的其他成分，如核仁、SC-35核斑点和端粒没有显著变化。此外，在所研究的猪间充质干细胞脂肪生成系统中，少量PML小体的存在是其特征。研究表明，不同来源的MSCs中核结构选定成分的排列非常相似，而脂肪细胞分化涉及核重组。本研究以猪作为模式生物，增加了脂肪生成过程中核组织的新数据。
