ABSTRACT
Adipose stem cells (ASCs) represent a reliable source of stem cells with a widely demonstrated potential in regenerative medicine and tissue engineering applications. New recent insights suggest that three-dimensional (3D) models may closely mimic the native tissue properties; spheroids from adipose derived stem cells (SASCs) exhibit enhanced regenerative abilities compared with those of 2D models. Stem cell therapy success is determined by "cell-quality"; for this reason, the involvement of stress signals and cellular aging need to be further investigated. Here, we performed a comparative analysis of genes connected with stemness, aging, telomeric length and oxidative stress, in 3D and 2D primary cultures. The expression levels of stemness-related markers and anti-aging Sirtuin1 were significantly up-regulated (P < 0.001) in SASCs-3D while gene expression of aging-related p16INK4a was increased in ASCs-2D (P < 0.001). The 3D and 2D cultures also had a different gene expression profile for genes related to telomere maintenance (Shelterin complex, RNA Binding proteins and DNA repair genes) (P < 0.01 and P < 0.001) and oxidative stress (aldehyde dehydrogenase class1 and 3) (P < 0.05, P < 0.01 and P < 0.001) and presented a striking large variation in their cellular redox state. Based on our findings, we propose a "cell quality" model of SASCs, highlighting a precise molecular expression of several genes involved with stemness (SOX2, POU5F1 and NANOG), anti-aging (SIRT1), oxidative stress (ALDH3) and telomeres maintenance.
Subject(s)
Adipocytes/metabolism , Adipose Tissue/cytology , Cell Culture Techniques , Stem Cell Transplantation , Stem Cells/cytology , Adipocytes/cytology , Adolescent , Adult , Aged , Aging/genetics , Cell Adhesion/genetics , Cell Survival/genetics , Cell- and Tissue-Based Therapy/methods , Cells, Cultured , Cyclin-Dependent Kinase Inhibitor p16/metabolism , DNA Repair/genetics , Female , Humans , Male , Middle Aged , Oxidative Stress/genetics , RNA-Binding Proteins/metabolism , Sirtuins/metabolism , Spheroids, Cellular/cytology , Telomere Homeostasis/genetics , Tissue Engineering/methods , Young AdultABSTRACT
Angiogenesis is a crucial process for the maintenance of normal tissue physiology and it is involved in tissue remodeling and regeneration. This process is essential for adipose tissue maintenance. The adipose tissue is composed by different cell types including stromal vascular cells as well as adipose stem cells (ASCs). In particular, ASCs are multipotent somatic stem cells that are able to differentiate and secrete several growth factors; they are recently emerging as a new cell reservoir for novel therapies and strategies in many diseases. Several studies suggest that ASCs have peculiar properties and participate in different disease-related processes such as angiogenesis. Furthermore, pathological expansion of adipose tissue brings to hypoxia, a major condition of unhealthy angiogenesis. Recent evidences have shown that microRNAs (miRNAs) play a crucial role also on ASCs as they take part in stemness maintenance, proliferation, and differentiation. It has been suggested that some miRNAs (MIR126, MIR31, MIR221 MIR222, MIR17-92 cluster, MIR30, MIR100 and MIR486) are directly involved in the angiogenic process by controlling multiple genes involved in this pathway. With the present review, we aim at providing an updated summary of the importance of adipose tissue under physiological and pathological conditions and of its relationship with neovascularization process. In particular, we report an overview of the most important miRNAs involved in angiogenesis focusing on ASCs. Hopefully the data presented will bring benefit in developing new therapeutic strategies.
Subject(s)
Adipose Tissue/physiology , MicroRNAs/genetics , Neoplasms/etiology , Neovascularization, Physiologic , Obesity/etiology , Adipose Tissue/cytology , Animals , Endothelial Cells/cytology , Endothelial Cells/metabolism , Humans , MicroRNAs/metabolism , Stem Cells/cytology , Stem Cells/metabolismABSTRACT
Two-dimensional (2D) cell cultures have been extensively used to investigate stem cell biology, but new insights show that the 2D model may not properly represent the potential of the tissue of origin. Conversely, three-dimensional cultures exhibit protein expression patterns and intercellular junctions that are more representative of their in vivo condition. Multiclonal cells that grow in suspension are defined as "spheroids," and we have previously demonstrated that spheroids from adipose-derived stem cells (S-ASCs) displayed enhanced regenerative capability. With the current study, we further characterized S-ASCs to further understand the molecular mechanisms underlying their stemness properties. Recent studies have shown that microRNAs (miRNAs) are involved in many cellular mechanisms, including stemness maintenance and proliferation, and adipose stem cell differentiation. Most studies have been conducted to identify a specific miRNA profile on adherent adipose stem cells, although little is still known about S-ASCs. In this study, we investigate for the first time the miRNA expression pattern in S-ASCs compared to that of ASCs, demonstrating that cell lines cultured in suspension show a typical miRNA expression profile that is closer to the one reported in induced pluripotent stem cells. Moreover, we have analyzed miRNAs that are specifically involved in two distinct moments of each differentiation, namely early and late stages of osteogenic, adipogenic, and chondrogenic lineages during long-term in vitro culture. The data reported in the current study suggest that S-ASCs have superior stemness features than the ASCs and they represent the true upstream stem cell fraction present in adipose tissue, relegating their adherent counterparts.
