Tomomi Nakamura

Fibroblast growth factor-2 stimulates directed migration of periodontal ligament cells via PI3K/AKT signaling and CD44/hyaluronan interaction.

Fibroblast growth factor‐2 (FGF‐2) regulates a variety of functions of the periodontal ligament (PDL) cell, which is a key player during tissue regeneration following periodontal tissue breakdown by periodontal disease. In this study, we investigated the effects of FGF‐2 on the cell migration and related signaling pathways of MPDL22, a mouse PDL cell clone. FGF‐2 activated the migration of MPDL22 cells and phosphorylation of phosphatidylinositol 3‐kinase (PI3K) and akt. The P13K inhibitors, Wortmannin and LY294002, suppressed both cell migration and akt activation in MPDL22, suggesting that the PI3K/akt pathway is involved in FGF‐2‐stimulated migration of MPDL22 cells. Moreover, in response to FGF‐2, MPDL22 showed increased CD44 expression, avidity to hyaluronan (HA) partly via CD44, HA production and mRNA expression of HA synthase (Has)‐1, 2, and 3. However, the distribution of HA molecular mass produced by MPDL22 was not altered by FGF‐2 stimulation. Treatment of transwell membrane with HA facilitated the migration of MPDL22 cells and an anti‐CD44 neutralizing antibody inhibited it. Interestingly, the expression of CD44 was colocalized with HA on the migrating cells when stimulated with FGF‐2. Furthermore, an anti‐CD44 antibody and small interfering RNA for CD44 significantly decreased the FGF‐2‐induced migration of MPDL22 cells. Taken together, PI3K/akt and CD44/HA signaling pathways are responsible for FGF‐2‐mediated cell motility of PDL cells, suggesting that FGF‐2 accelerates periodontal regeneration by regulating the cellular functions including migration, proliferation and modulation of extracellular matrix production. J. Cell. Physiol. 226: 809–821, 2011.

TGF-Beta Negatively Regulates the BMP2-Dependent Early Commitment of Periodontal Ligament Cells into Hard Tissue Forming Cells

Transforming growth factor beta (TGF-β) is a multi-functional growth factor expressed in many tissues and organs. Genetic animal models have revealed the critical functions of TGF-β in craniofacial development, including the teeth and periodontal tissue. However, the physiological function of TGF-β in the periodontal ligament (PDL) has not been fully elucidated. In this study, we examined the roles of TGF-β in the cytodifferentiation of PDL cells using a TGF-β receptor kinase inhibitor, SB431542. Mouse PDL cell clones (MPDL22) were cultured in calcification-inducing medium with or without SB431542 in the presence or absence of various growth factors, such as bone morphogenetic protein (BMP)-2, TGF-β and fibroblast growth factor (FGF)-2. SB431542 dramatically enhanced the BMP-2-dependent calcification of MPDL22 cells and accelerated the expression of ossification genes alkaline phosphatase (ALPase) and Runt-related transcription factor (Runx) 2 during early osteoblastic differentiation. SB431542 did not promote MPDL22 calcification without BMP-2 stimulation. The cell growth rate and collagen synthesis during the late stage of MPDL22 culture were retarded by SB431542. Quantitative reverse transcription polymerase chain reaction analysis revealed that the expressions of Smurf1 and Smad6, which are negative feedback components in the TGF-β/BMP signaling pathway, were downregulated in MPDL22 cells with SB431542 treatment. These results suggest that an endogenous signal from TGF-β negatively regulates the early commitment and cytodifferentiation of PDL cells into hard tissue-forming cells. A synthetic drug that regulates endogenous TGF-β signals may be efficacious for developing periodontal regenerative therapies.

Prediction of mean pulmonary wedge pressure using Doppler pulmonary venous flow variables in hypertrophic cardiomyopathy

We examined whether pulmonary venous flow variables, assessed by transthoracic Doppler echocardiography, could predict mean pulmonary wedge pressure in hypertrophic cardiomyopathy. Forty-four patients with no left ventricular systolic dysfunction (left ventricular fractional shortening > or =25%) were studied. Forty patients with systolic dysfunction (dilated cardiomyopathy group) served as control. Mitral and pulmonary venous flow velocity curves were recorded with the pulsed-Doppler method and were related to mean pulmonary wedge pressure obtained by right heart catheterization. In hypertrophic cardiomyopathy group, the systolic (r=-0.15, P=0.335) and diastolic (r=0.35, P=0.022) forward flow velocity were poorly related to mean pulmonary wedge pressure, whereas the velocity of atrial reversal (r=0.68, P<0.001) correlated well with mean pulmonary wedge pressure. In dilated cardiomyopathy group, the systolic (r=-0.51, P=0.001) and diastolic (r=0.60, P<0.001) forward flow velocity were strongly related to mean pulmonary wedge pressure. With the cut-off value set at the velocity of atrial reversal >30 cm/s in hypertrophic cardiomyopathy group, the sensitivity for predicting mean pulmonary wedge pressure >15 mmHg was 79% and the specificity was 73%. In conclusion, the atrial component of the pulmonary venous flow can be used to predict mean pulmonary wedge pressure in hypertrophic cardiomyopathy.