Expression analysis of α-smooth muscle actin and tenascin-C in the periodontal ligament under orthodontic loading or in vitro culture

Abstract

α-smooth muscle actin (α-SMA) and tenascin-C are stress-induced phenotypic features of myofibroblasts. The expression levels of these two proteins closely correlate with the extracellular mechanical microenvironment. We investigated how the expression of α-SMA and tenascin-C was altered in the periodontal ligament (PDL) under orthodontic loading to indirectly reveal the intrinsic mechanical microenvironment in the PDL. In this study, we demonstrated the synergistic effects of transforming growth factor-β1 (TGF-β1) and mechanical tensile or compressive stress on myofibroblast differentiation from human periodontal ligament cells (hPDLCs). The hPDLCs under higher tensile or compressive stress significantly increased their levels of α-SMA and tenascin-C compared with those under lower tensile or compressive stress. A similar trend was observed in the tension and compression areas of the PDL under continuous light or heavy orthodontic load in rats. During the time-course analysis of expression, we observed that an increase in α-SMA levels was matched by an increase in tenascin-C levels in the PDL under orthodontic load in vivo. The time-dependent variation of α-SMA and tenascin-C expression in the PDL may indicate the time-dependent variation of intrinsic stress under constant extrinsic loading.

Transgelin mediates transforming growth factor‐β1‐induced proliferation of human periodontal ligament cells

“…Considering that cell populations in PDL tissue contract and stretch repeatedly in a similar manner to vascular muscle cells because of their constant exposure to masticatory and occlusal pressure, PDL cells might share some characters with smooth muscle cells. Alternatively, PDL cells expressing transgelin strongly could possess the characteristics of myofibroblast as it has been reported that TGF‐β1 induced the differentiation of PDL cells into myofibroblasts under specific conditions . To clarify the characteristics of PDL cells expressing α‐SMA or transgelin in detail, further studies are needed.…”

“…Alternatively, PDL cells expressing transgelin strongly could possess the characteristics of myofibroblast as it has been reported that TGF-β1 induced the differentiation of PDL cells into myofibroblasts under specific conditions. 33 To clarify the characteristics of PDL cells expressing α-SMA or transgelin in detail, further studies are needed.…”

Sclerostin Promotes Bone Remodeling in the Process of Tooth Movement

“…The methods used were as previously described [30]. In brief, rats were anesthetized by an intraperitoneal injection of 10% chloral hydrate (3 mg/kg).…”

“…Complementary DNA (cDNA) was prepared by using a TaKaRa PrimerScript 1 st Strand cDNA Synthesis Kit (TaKaRa, Tokyo, Japan) andRT-qPCR was done as previously described [33]. Briefly, a total 20μL cDNA mixture was subjected to PCR amplification.…”

Expression of α-smooth muscle actin in the periodontal ligament during post-emergent tooth eruption

“… 14 α-SMA-positive cells are also present in the PDL during orthodontic tooth movement, indicating that enhanced mechanical stress promotes myofibroblast differentiation. 15 …”