3 research outputs found
Softening Substrates Promote Chondrocytes Phenotype via RhoA/ROCK Pathway
Due
to its evascular, aneural, and alymphatic conditions, articular
cartilage shows extremely poor regenerative ability. Thus, directing
chondrocyte toward a desired location and function by utilizing the
mechanical cues of biomaterials is a promising approach for effective
tissue regeneration. However, chondrocytes cultured on Petri dish
will lose their typical phenotype which may lead to compromised results.
Therefore, we fabricated polydimethylsiloxane (PDMS) materials with
various stiffness as culture substrates. Cell morphology and focal
adhesion of chondrocytes displayed significant changes. The cytoskeletal
tension of the adherent cells observed by average myosin IIA fluorescent
intensity increased as stiffness of the underlying substrates decreased,
consistent with the alteration of chondrocyte phenotype in our study.
Immunofluorescent images and q-PCR results revealed that chondrocyte
cultured on soft substrates showed better chondrocyte functionalization
by more type II collagen and aggrecan expression, related to the lowest
mRNA level of Rac-1, RhoA, ROCK-1, and ROCK-2. Taken together, this
work not only points out that matrix elasticity can regulate chondrocyte
functionalization via RhoA/ROCK pathway, but also provides new prospect
for biomechanical control of cell behavior in cell-based cartilage
regeneration
Fabrication of Calcium Phosphate Microflowers and Their Extended Application in Bone Regeneration
The
structure of materials is known to play an important role in material
function. Nowadays, flowerlike structures have gained attention for
studies not only in analytical chemistry, but also in biomaterial
design. In this study, flowerlike structures were applied in bone
regeneration in the form of calcium phosphate microflowers. The material
was synthesized by a simple and environmentally friendly method. We
characterized the structure and properties of the microflower using
various methods. Cytotoxicity and osteogenesis-related gene regulations
of the microflower were investigated <i>in vitro</i>. Cell
uptake was observed by immunofluorescence. Rat calvarial critical-size
defect models were successfully established to further confirm the
enhanced bone regeneration ability of this material. We expect that
this novel study will be of practical importance for the extended
application of flowerlike materials and will provide new insights
into the optimization of the morphology of calcium phosphate materials
Anti-inflammatory and Antioxidative Effects of Tetrahedral DNA Nanostructures via the Modulation of Macrophage Responses
Tetrahedral
DNA nanostructures (TDNs) are a new type of nanomaterials that have
recently attracted attention in the field of biomedicine. However,
the practical application of nanomaterials is often limited owing
to the host immune response. Here, the response of RAW264.7 macrophages
to TDNs was comprehensively evaluated. The results showed that TDNs
had no observable cytotoxicity and could induce polarization of RAW264.7
cells to the M1 type. TDNs attenuated the expression of NO IL-1β
(interleukin-1β), IL-6 (interleukin-6), and TNF-α (tumor
necrosis factor-α) in LPS-induced RAW264.7 cells by inhibiting
MAPK phosphorylation. In addition, TDNs inhibited LPS-induced reactive
oxygen species (ROS) production and cell apoptosis by up-regulating
the mRNA expression of antioxidative enzyme heme oxygenase-1 (HO-1).
The findings of this study demonstrated that TDNs have great potential
as a novel theranostic agent because of their anti-inflammatory and
antioxidant activities, high bioavailability, and ease of targeting