Roles of Collagen Molecules in Growth and Differentiation of Human Osteoblasts

Impact of red-lime and white-lime betel quid on oral cell lines: Cytotoxicity and effects on fibronectin and type I collagen expression

Background/purpose

Chewing betel quid is linked to an increased risk of oral cancer. This study investigates the effects of red-lime and white-lime betel quid extracts on oral cell lines, focusing on cytotoxicity and their influence on fibronectin and Type I collagen expression, which were crucial for oral tissue integrity and cancer development.

Materials and methods

Four oral cell lines, human gingival fibroblasts, tongue squamous cell carcinoma cells, human periodontal ligament fibroblasts, and human fetal osteoblasts, were treated with red-lime and white-lime betel quid extracts. Cytotoxicity assays and Western blotting were used to assess cell viability and protein expression.

Results

Both red-lime and white-lime betel quid extracts exhibited dose-dependent effects on all tested cell lines, with variations in sensitivity observed among cell types. Notably, red-lime betel quid exerted stronger cytotoxic effects on human gingival fibroblasts and human fetal osteoblasts. Red-lime betel quid increased fibronectin and Type I collagen in periodontal ligament fibroblasts but reduced both proteins in fetal osteoblasts. White-lime betel quid extract generally elevated fibronectin and decreased Type I collagen across cell lines.

Conclusion

This study reveals a nuanced, concentration-dependent impact of betel quid extracts on oral cells, with significant variability in cytotoxicity and changes in fibronectin and Type I collagen expression. These findings suggest that abrupt cessation of betel quid chewing can lead to dental issues such as mobile teeth. Red-lime betel quid uniquely affects periodontal ligament fibroblasts by increasing both fibronectin and Type I collagen.

Strategies of nanoparticles integration in polymer fibers to achieve antibacterial effect and enhance cell proliferation with collagen production in tissue engineering scaffolds

Current design strategies for biomedical tissue scaffolds are focused on multifunctionality to provide beneficial microenvironments to support tissue growth. We have developed a simple yet effective approach to create core-shell fibers of poly(3-hydroxybuty-rate-co-3-hydroxyvalerate) (PHBV), which are homogenously covered with titanium dioxide (TiO2) nanoparticles. Unlike the blend process, co-axial electrospinning enabled the uniform distribution of nanoparticles without the formation of large aggregates. We observed 5 orders of magnitude reduction in Escherichia coli survival after contact with electrospun scaffolds compared to the non-material control. In addition, our hybrid cores-shell structure supported significantly higher osteoblast proliferation after 7 days of cell culture and profound generation of 3D networked collagen fibers after 14 days. The organic-inorganic composite scaffold produced in this study demonstrates a unique combination of antibacterial properties and increased bone regeneration properties. In summary, the multifunctionality of the presented core-shell cPHBV+sTiO2 scaffolds shows great promise for biomedical applications.

The Lymphatic Endothelial Cell Secretome Inhibits Osteoblast Differentiation and Bone Formation

Complex lymphatic anomalies (CLAs) are a set of rare diseases with unique osteopathic profiles. Recent efforts have identified how lymphatic-specific somatic activating mutations can induce abnormal lymphatic formations that are capable of invading bone and inducing bone resorption. The abnormal bone resorption in CLA patients has been linked to overactive osteoclasts in areas with lymphatic invasions. Despite these findings, the mechanism associated with progressive bone loss in CLAs remains to be elucidated. In order to determine the role of osteoblasts in CLAs, we sought to assess osteoblast differentiation and bone formation when exposed to the lymphatic endothelial cell secretome. When treated with lymphatic endothelial cell conditioned medium (L-CM), osteoblasts exhibited a significant decrease in proliferation, differentiation, and function. Additionally, L-CM treatment also inhibited bone formation through a neonatal calvaria explant culture. These findings are the first to reveal how osteoblasts may be actively suppressed during bone lymphatic invasion in CLAs.

Multi-pin contact drawing enables production of anisotropic collagen fiber substrates for alignment of fibroblasts and monocytes

Type I collagen is the most abundant protein in the human body and is known to play important roles in numerous biological processes including tissue morphogenesis and wound healing. As such, it is one of the most frequently used substrates for cell culture, and there have been considerable efforts to develop collagen-based cell culture substrates that mimic the structural organization of collagen as it is found in native tissues, i.e., collagen fibers. However, producing collagen fibers from extracted collagen has been notoriously difficult, with existing methods providing only low throughput production of collagen fibers. In this study, we prepared collagen fibers using a highly efficient, bio-friendly, and cost-effective approach termed contact drawing, which uses an entangled polymer fluid to aid in fiber formation. Contact drawing technology has been demonstrated previously for collagen using highly concentrated dextran solutions with low concentrations of collagen. Here, we show that by replacing dextran with polyethylene oxide (PEO), high collagen content fibers may be readily formed from mixtures of soluble collagen and PEO, a polymer that readily forms fibers by contact drawing at concentrations as low as 0.5%wt. The presence of collagen and the formation of well-ordered collagen structures in the resulting fibers were characterized by attenuated total reflectance Fourier-transform infrared spectromicroscopy, Raman spectromicroscopy, and fluorescence microscopy. Corresponding to well-ordered collagen, the mechanical properties of the PEO-collagen fibers approximated those observed for native collagen fibers. Growth of cells on aligned PEO-collagen fibers attached to a polydimethyl siloxane support was examined for human dermal fibroblast (WS1) and human peripheral leukemia blood monocyte (THP-1) cell lines. WS1 and THP-1 cells readily attached, displayed alignment through migration and spreading, and proliferated on the collagen fiber substrate over the course of several days. We also demonstrated the retrieval of viable cells from the PEO-collagen fiber substrates through enzymatic digestion of the collagen substrate with collagenase IV.

Complex effects of Mg-biomaterials on the osteoblast cell machinery: A proteomic study

The cell-biomaterial interface is highly complex; thousands of molecules and many processes participate in its formation. Growing demand for improved biomaterials has highlighted the need to understand the structure and functions of this interface. Proteomic methods offer a viable alternative to the traditional in vitro techniques for analyzing such systems. Magnesium is a promoter of cell adhesion and osteogenesis. Here, we used the LC-MS/MS to compare the protein expression profiles of human osteoblasts (HOb) exposed to sol-gel coatings without (MT) and with Mg (MT1.5Mg) for 1, 3, and 7 days. PANTHER, DAVID, and IPA databases were employed for protein identification and data analysis. Confocal microscopy and gene expression analysis were used for further characterization. Exposure to MT1.5Mg increased the HOb cell area and the expression of SP7, RUNX2, IBP3, COL3A1, MXRA8, and FBN1 genes. Proteomic analysis showed that MT1.5Mg affected the early osteoblast maturation (PI3/AKT, mTOR, ERK/MAPK), insulin metabolism, cell adhesion (integrin, FAK, actin cytoskeleton regulation) and oxidative stress pathways. Thus, the effects of Mg on cell adhesion and osteogenesis are rather complex, affecting several pathways rather than single processes. Our analysis also confirms the potential of proteomics in biomaterial characterization, showing a good correlation with in vitro results.

Vapor-phased fabrication and modulation of cell-laden scaffolding materials

Bottom-up approaches using building blocks of modules to fabricate scaffolds for tissue engineering applications have enabled the fabrication of structurally complex and multifunctional materials allowing for physical and chemical flexibility to better mimic the native extracellular matrix. Here we report a vapor-phased fabrication process for constructing three-dimensional modulated scaffold materials via simple steps based on controlling mass transport of vapor sublimation and deposition. We demonstrate the fabrication of scaffolds comprised of multiple biomolecules and living cells with built-in boundaries separating the distinct compartments containing defined biological configurations and functions. We show that the fabricated scaffolds have mass production potential. We demonstrate overall >80% cell viability of encapsulated cells and that modulated scaffolds exhibit enhanced cell proliferation, osteogenesis, and neurogenesis, which can be assembled into various geometric configurations. We perform cell co-culture experiments to show independent osteogenesis and angiogenesis activities from separate compartments in one scaffold construct.