Graduate Student University of Arkansas, Fayetteville, United States
Introduction:: The elastic matrix is essential for providing structural support and maintaining tissue homeostasis, particularly in vascular tissue such as the abdominal aorta. However, inflammation can disrupt the microenvironment of the tunica media via proteolytic and apoptotic activity, which limits the restoration of the elastic matrix in adult smooth muscle cells. Stem cells, including bone marrow and adipose-derived stem cells, have been proposed as a potential therapeutic source due to their multipotency and immunogenicity. Bone marrow stem cell-derived smooth muscle cells have demonstrated the ability to restore elastogenesis and provide anti-proteolytic activity in an in vitro elastase-induced model of abdominal aortic aneurysm. In this study, we aim to investigate the potential of stem cell-derived smooth muscle cells to provide anti-inflammatory, anti-proteolytic, and elastogenic properties through quantitative and
qualitative protein arrays, and a quantitative elastin assay.
Materials and Methods:: The study consisted of seven experimental groups with three samples in each group. The groups included human aortic smooth muscle controls, undifferentiated bone marrow and adipose stem cell controls, bone marrow-derived smooth muscle cells, adipose-derived smooth muscle cells, and both differentiated cell groups subjected to serum-free post-differentiation. Bone marrow stem cells were differentiated for 7 days and adipose for 4 days, followed by 14 day post-differentiation. The conditioned medium was collected, aliquoted, and frozen at -20°C for further analysis. Medium samples were analyzed for disease biomarkers using multi-protein membranes, and custom multiplex antibody-bead arrays. The results of this study will provide insights into the potential of stem cell-derived smooth muscle cells as a therapeutic approach for the restoration of the elastic matrix in abdominal aortic aneurysms and other cardiovascular diseases.
Results, Conclusions, and Discussions:: The conditioned medium was characterized using chemiluminescent membrane arrays and multiplexed antibody-bead arrays. Markers were classified as either inflammatory, anti-inflammatory, immunomodulatory, and proteolytic or anti-proteolytic. The most interesting finding was that stem cell-derived smooth muscle cells demonstrated lower levels of anti-inflammatory proteins when compared to their human aortic smooth muscle cell controls. However, stem cell-derived smooth muscle cells cultured in serum displayed higher levels of all proteins than those cultured in a serum-free medium. Serum-free smooth also demonstrated significantly lower levels of all proteins when compared to undifferentiated controls which indicates that serum plays a role in the post-differentiation process. However, differentiated smooth muscle cells post-differentiated in the presence of serum displayed higher levels of several inflammatory and proteolytic proteins which could also result from serums’ effects on cellular secretions.
In conclusion, this study has provided valuable insights into the protein expression profiles of stem cell-derived smooth muscle cells and the impact of serum on their post-differentiation process. It was observed that stem cell-derived smooth muscle cells exhibit lower levels of anti-inflammatory proteins compared to human aortic smooth muscle cell controls. Additionally, the presence of serum in the culture medium was found to significantly influence the protein expression levels, with higher levels of inflammatory, proteolytic, and other markers observed in serum-cultured cells compared to serum-free conditions. Furthermore, the results suggest that serum plays a pivotal role in the post-differentiation process, potentially affecting cellular secretions and contributing to an increase in inflammatory and proteolytic proteins. Future studies may focus on the mechanisms by which serum influences these processes and identify strategies to modulate protein expression for potential therapeutic applications in tissue engineering and regenerative medicine.
