Genetic profiling of human bone marrow and adipose tissue-derived mesenchymal stem cells reveals differences in osteogenic signaling mediated by graphene

Abstract

Background In the last decade, graphene surfaces have consistently supported osteoblast development of stem cells, holding promise as a therapeutic implant for degenerative bone diseases. However, until now no study has specifically examined the genetic changes when stem cells undergo osteogenic differentiation on graphene. Results In this study, we provide a detailed overview of gene expressions when human mesenchymal stem cells (MSCs) derived from either adipose tissue (AD-MSCs) or bone marrow (BM-MSCs), are cultured on graphene. Genetic expressions were measured using osteogenic RT2 profiler PCR arrays and compared either over time (7 or 21 days) or between each cell source at each time point. Genes were categorized as either transcriptional regulation, osteoblast-related, extracellular matrix, cellular adhesion, BMP and SMAD signaling, growth factors, or angiogenic factors. Results showed that both MSC sources cultured on low oxygen graphene surfaces achieved osteogenesis by 21 days and expressed specific osteoblast markers. However, each MSC source cultured on graphene did have genetically different responses. When compared between each other, we found that genes of BM-MSCs were robustly expressed, and more noticeable after 7 days of culturing, suggesting BM-MSCs initiate osteogenesis at an earlier time point than AD-MSCs on graphene. Additionally, we found upregulated angiogenic markers in both MSCs sources, suggesting graphene could simultaneously attract the ingrowth of blood vessels in vivo. Finally, we identified several novel targets, including distal-less homeobox 5 (DLX5) and phosphate-regulating endopeptidase homolog, X-linked (PHEX). Conclusions Overall, this study shows that graphene genetically supports differentiation of both AD-MSCs and BM-MSCs but may involve different signaling mechanisms to achieve osteogenesis. Data further demonstrates the lack of aberrant signaling due to cell-graphene interaction, strengthening the application of specific form and concentration of graphene nanoparticles in bone tissue engineering. Graphic abstract

Xenogenic Implantation of Human Mesenchymal Stromal Cells Using a Novel 3D-Printed Scaffold of PLGA and Graphene Leads to a Significant Increase in Bone Mineralization in a Rat Segmental Femoral Bone Defect

“…The in vitro results demonstrated that human ADMSCs adhere, proliferate, and cluster on the scaffolds for up to 21 days ( Figure 2 ). These data support our prior studies and publications from other investigators, demonstrating the cytocompatibility and the osteogenic response of goat and human MSCs on graphene films in vitro [ 13 , 14 , 15 , 16 , 17 , 32 ]. The cell behavior also confirms that there are no adverse effects when a 99.95% PLGA blend is used as a binder for the LOG nanoparticles to fabricate a 3D scaffold for in vivo applications.…”

“…This form of graphene is referred to as low-oxygen graphene (LOG). The synthesis and physicochemical properties of LOG nanoparticles have been described earlier [ 15 , 17 , 31 , 32 ]. The physicochemical properties were confirmed to be identical to those reported earlier.…”

“…Reports from several groups, including ours, have shown that nanocomposites containing graphene and its derivatives have varying physical and chemical properties, by virtue of which they can affect cell behavior. We and other groups have shown that graphene-containing nanocomposites can promote adhesion, proliferation, and osteogenic differentiation of MSCs in vitro and in vivo [ 13 , 14 , 15 , 16 , 17 ], making graphene nanoparticles strong candidates for bone tissue engineering.…”

“…Hence, it is likely that the osteogenic effect is primarily due to the osteogenic agents, such as HA or BMP2. Most importantly, we have reported that the topographical features or, in general, the physicochemical properties of the oxidized form of graphene nanoparticles create an osteogenic environment for mesenchymal stem cells in vitro, thus inducing cells to undergo osteogenesis without any chemical induction [ 15 , 17 ]. Hence, the fabrication of an optimal 3D scaffold for in vivo studies is the next step.…”

Impact of Graphene Derivatives as Artificial Extracellular Matrices on Mesenchymal Stem Cells

“…MacDonald et al studied the incubation of human MSCs into a graphene dispersion for 1, 5, 24 and 96 h at 37 • C [134]. The cells were detached with trypsin and centrifuged for 5 min.…”