Regulation of matrix remodelling phenotype in gingival fibroblasts by substratum topography

Abstract

Gingival connective tissue often has a composition resembling that of scar surrounding dental implant abutments. Increased cell adhesion, α-smooth muscle actin (α-SMA) expression and increased extracellular matrix deposition are a hallmark of fibrotic cells, but how topographic features influence gingival fibroblast adhesion and adoption of the α-SMA positive myofibroblast phenotype associated with scarring is unknown. The purpose of the present study was to demonstrate whether implant topographies that limit adhesion formation would reduce myofibroblast differentiation and extracellular matrix deposition. Human gingival fibroblasts were cultured on PT (smooth) and SLA (roughened) titanium discs for varying time-points. At 1 and 2 weeks after seeding, incorporation of α-SMA into stress-fibre bundles and fibronectin deposition was significantly higher on PT than SLA surfaces indicating differentiation of the cells towards a myofibroblast phenotype. Analysis of adhesion formation demonstrated that cells formed larger adhesions and more stable adhesions on PT, with more nascent adhesions observed on SLA. Gene expression analysis identified up-regulation of 15 genes at 24 hrs on SLA versus PT associated with matrix remodelling. Pharmacological inhibition of Src/FAK signalling in gingival fibroblasts on PT reduced fibronectin deposition and CCN2 expression. We conclude that topographical features that reduce focal adhesion stability could be applied to inhibit myofibroblast differentiation in gingival fibroblasts.

Effect of Clinically Relevant CAD/CAM Zirconia Polishing on Gingival Fibroblast Proliferation and Focal Adhesions

“…Previous research has shown that the modification of the substrate modulates FA sites [ 11 , 62 ]. For example, FAs have been reported to increase on smoother surfaces compared to rougher surfaces [ 35 ].…”

Sensing the Difference: The Influence of Anisotropic Cues on Cell Behavior

“…However, Anselme et al have indicated potential positive effects for grooves in metals (Anselme et al, 2004). We further note that other cell types have been shown to be responsive to topographies in metals -again though, roughened rather than grooved (Lee et al, 2014;Kim et al, 2015).…”

Titanium Substratum Roughness as a Determinant of Human Gingival Fibroblast Fibronectin and α-Smooth Muscle Actin Expression

“…Fabrication of each topography was performed as previously described [ 16 , 21 ]. Briefly, Commercially-pure titanium (Cp-Ti) (Baoji Titanium Industry Co., Ltd., Baoji, China) was cut into 1-mm thick discs from Cp-Ti rods 15 mm in diameter.…”

“…We have previously shown that sand blast, large grit, acid-etch (SLA) roughened titanium topographies can be utilized to reduce myofibroblast differentiation in HGFs. The roughened topographical features induce nascent adhesion formation in HGFs which attenuates α-SMA expression, fibronectin synthesis, stress fiber assembly, and is concomitant with an upregulation of genes associated with matrix remodeling [ 21 ]. This study provides direct evidence that alterations in titanium substratum roughness can be utilized to reduce myofibroblast differentiation of HGFs.…”

“…Titanium, with lower arithmetic average of the absolute profile height deviations (Ra) = 3.39 μm (Tis-OPAAE) while shown to promote HGF adhesion, also permitted bacterial colonization [ 22 ]. Our previous observations suggest that substratum roughness restricts sites for HGFs to form adhesions inhibiting myofibroblast differentiation as opposed to the average topographical depth of the features [ 21 ]. We hypothesized that roughened topographical features could be produced with a lower R a that would inhibit a scarring phenotype in HGF, while reducing the area for bacterial colonization.…”