Electrostatically mediated layer-by-layer assembly of nitrogen-doped graphene/PDDA/gold nanoparticle composites for electrochemical detection of uric acid.

A layer-by-layer self-assembled nitrogen-doped graphene/PDDA/gold nanoparticle (NDG/PDDA/GNP) composite was described. Citrate-stabilizing gold nanoparticle colloids (GNPs) were electrostatically adsorbed onto NDG nanosheets using a cationic polyelectrolyte, polydiallyldimethylammonium (PDDA), as the linker, thereby creating a high-performance electrochemical interface. The morphology and chemical composition were characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, infrared spectroscopy, and Raman spectroscopy. Analytical application was manifested by electrochemical sensing of uric acid (UA), a biomarker involved with a variety of clinical diseases. The prepared nanocomposite exhibited noticeable electroactivity to uric acid oxidation and can give effective peak separation with ascorbic acid and dopamine. Additionally, the nanocomposite practically averted from other potentially interferents including glucose, urea, and serotonin, thus allowing selective voltammetric detection of UA in the biological matrix. Under the optimal condition, peak currents measured by differential pulse voltammetry were proportional to UA concentrations in the range of 0.5~100 µM (R2 = 0.998), with the detection limit of 53 nM. The NDG/PDDA/GNP nanocomposite as presented herein holds potential for aiding the diagnosis of UA-associated diseases and should be a new opportunity for biochemical analysis and biosensing applications. Graphical abstract.

Spectral resolved study of filamentation effect on the nonlinear absorption in carbon disulfide.

A Z-scan system using spectrometers as detectors is established to investigate nonlinear absorption and white light continuum separately, in which absorption coefficient that is coincident with previous work was obtained. After Z-scan experiments, spot photographs were captured to further study the spatial properties of filaments in CS2, and we obtained similar space between dual filaments with previous work. Using the experimental setup, we find that plasma generation is the main effect impacting the nonlinear absorption and refraction process, and this impact can be eliminated in the case of CS2. Therefore, effect of filamentation can be neglected for CS2. Though it is easy to generate filaments in CS2 at relatively low intensity, fitting the Z-scan curve with three-photon model at 800 nm for CS2 is reasonable. In addition, the thickness of sample can affect extracted absorption coefficient of CS2 by affecting the length of filamentation.

EMP3 is induced by TWIST1/2 and regulates epithelial-to-mesenchymal transition of gastric cancer cells.

In this study, we aimed to explore new downstream effectors of TWIST1/2 in inducing epithelial-to-mesenchymal transition in gastric cancer. Bioinformatic data mining was performed using data in The Cancer Genome Atlas Stomach Adenocarcinoma. Survival curves were generated using Kaplan-Meier plotter. Gastric cancer cell lines (AGS and SGC-7901) were used as in vitro cell model to investigate the regulative effect of TWIST1/2 on epithelial membrane protein 3 expression and the progression of epithelial-to-mesenchymal transition. Results showed that TWIST1 and TWIST2 are usually co-upregulated in patients with primary gastric cancer. High TWIST1 expression is associated with worse overall survival (hazard ratio = 1.26; 95% confidence interval = 1.06-1.49; p = 0.007) and also worse first progression-free survival (hazard ratio = 1.47; 95% confidence interval = 1.18-1.82; p < 0.0001). Similarly, high TWIST2 expression is associated with unfavorable overall survival (hazard ratio = 1.71; 95% confidence interval = 1.32-2.22; p < 0.0001) and progression-free survival (hazard ratio = 1.99; 95% confidence interval = 1.45-2.72; p < 0.0001). Epithelial membrane protein 3 is negatively correlated to CDH1 expression (Pearson's r = -0.46) but is positively correlated to VIM expression (Pearson's r = 0.83). Knockdown of epithelial membrane protein 3 significantly increased E-cadherin but significantly decreased Vimentin expression in AGS cells. Gastric cancer patients with metastasis have significantly higher epithelial membrane protein 3 expression than the cases without metastasis. In addition, high epithelial membrane protein 3 expression is associated with worse overall survival (hazard ratio = 2.59; 95% confidence interval = 2.06-3.26; p < 0.0001) and also worse progression-free survival (hazard ratio = 2.21; 95% confidence interval = 1.78-2.74; p < 0.0001). In conclusion, epithelial membrane protein 3 is a downstream effector of TWIST1/2 in inducing epithelial-to-mesenchymal transition in gastric cancer. Epithelial membrane protein 3 upregulation might be associated with gastric cancer metastasis and is a potential indicator of unfavorable overall survival and progression-free survival in gastric cancer patients.

4-hydroxy-2(3H)-benzoxazolone alleviates acetaminophen-induced hepatic injury by inhibiting NF-κB and activating Nrf2/HO-1 signaling pathways.

The purpose of this study is to evaluate the protective effect of 4-hydroxy-2(3H)-benzoxazolone from Acanthus ilicifolius (HBAI) on acute liver injury induced by acetaminophen in mice and its mechanism. Mice were continuously treated with HBAI (200, 100, 50 mg/kg) once a day for 10 days. After that, the mice were fasted for 8 hours, followed by intraperitoneal injection of acetaminophen (300 mg/kg). The results showed that HBAI pretreatment significantly reduced acetaminophen-induced liver tissue congestion, hepatocyte apoptosis and necrosis, and inflammatory cell infiltration. HBAI could effectively reduce the levels of serum alanine aminotransferase, aspartate aminotransferase, total bilirubin, reactive oxygen species and malondialdehyde. Interestingly, the activities of liver catalase, superoxide dismutase, glutathione and glutathione reductase were enhanced by HBAI pretreatment. Moreover, HBAI pretreatment alleviated acetaminophen-induced hepatocyte apoptosis by regulating the expression of Bcl-2 family proteins and the mitochondrial function. Further study showed that HBAI pretreatment effectively promoted the expression of Nrf2 and its signal downstream HO-1, NQO1, GCLC, GCLM, and MGST-1, suggesting the activation of the Nrf2/HO-1 signaling pathway. Meanwhile, HBAI attenuated the phosphorylation of NF-κBp65, IKKα/ß, and IκBα, as well as the expression of NF-κBp50, which indicated that HBAI blocked the signal transduction of NF-κB pathway. In conclusion, HBAI protects against acetaminophen-induced acute liver injury by inhibiting the NF-κB and activating Nrf2/HO-1 signaling pathways.

4-hydroxybenzo[d]oxazol-2(3H)-one ameliorates LPS/D-GalN-induced acute liver injury by inhibiting TLR4/NF-κB and MAPK signaling pathways in mice.

The purpose of this study was to synthesize 4-hydroxybenzo[d]oxazol-2(3H)-one (HBO) and to investigate its protective effects on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury. HBO (C7H5O3N) was synthesized based on 2-nitro-resorcinol and identified by physicochemical analysis. In the animal experiment, mice were pretreated with HBO (50, 100, 200 mg/kg) for 10 days. At the end of pretreatment, the animals were injected with LPS (10 µg/kg)/D-GalN (700 mg/kg). The results showed that HBO significantly alleviated liver injury induced by LPS/D-GalN in mice. It remarkably decreased inflammatory response by reducing the levels of tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß). Moreover, HBO notably attenuated hepatocyte apoptosis by inhibiting the release of Cytochrome C (Cyt C) from mitochondria into the cytoplasm and regulating the expression of B-cell lymphoma-2 (Bcl-2) family. Furthermore, the result showed that HBO inhibited the expressions of nuclear factor kappa-B p50 (NF-κBp50), toll-like receptor 4 (TLR4), and myeloid differentiation factor 88 (MyD88), as well as the phosphorylation of inhibitor of nuclear factor kappa-B (IκB), inhibitor of nuclear factor kappa-B kinase-α/ß (IKK-α/ß), nuclear factor kappa-B p65 (NF-κBp65), suggesting that HBO had a certain influence on the TLR4/NF-κB pathway. In addition, the mitogen-activated protein kinase (MAPK) signaling pathway was also affected by HBO, as evidenced by the decrease in the phosphorylation levels of extracellular regulated protein kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38). In conclusion, our study suggested that HBO could protect against LPS/D-GalN-induced liver injury, moreover, treatment with HBO appeared to be capable of further regulating the TLR4/NF-κB and MAPK signaling pathways.

Inhibition of lysophosphatidic acid receptor-2 expression by RNA interference decreases lysophosphatidic acid-induced urokinase plasminogen activator activation, cell invasion, and migration in ovarian cancer SKOV-3 cells.

AIM: To explore the role of lysophosphatidic acid receptor-2 (LPA2) in regulating lysophosphatidic acid (LPA)-induced urokinase plasminogen activator (uPA) activation, cell invasion, and migration in human ovarian cancer cell line SKOV-3. METHODS: SKOV-3 cells were stimulated with LPA. Cell supernatant uPA level and activity were measured using enzyme-linked immunosorbent assay. LPA2 mRNA expression was inhibited with LPA2-specific small interfering RNA (siRNA) and examined using semiquantitative reverse transcriptase-polymerase chain reaction. LPA-induced cell invasion and migration in transfected cells were evaluated by a Matrigel invasion chamber and a Transwell chemotaxis chamber, respectively. RESULTS: LPA stimulation significantly enhanced in vitro uPA activity in time- and dose-dependent manner. The levels of LPA-induced uPA protein decreased by 55% in LPA2 siRNA-transfected cells compared with negatively transfected cells at 24 hours after being treated with 80 micromol/L LPA (0.75+/-0.03 vs 0.34+/-0.04, P=0.004). In the LPA2 specific siRNA-transfected SKOV-3 cells, LPA treatment at 80 micromol/L induced considerably less invasion and migration compared with negative control siRNA-transfected SKOV-3 cells (invasion: 178+/-17.2 vs 36.2+/-3.3, P=0.009; migration: 220.4+/-25.5 vs 57+/-7.6, P=0.009). CONCLUSION: LPA2 has an essential role in LPA-induced uPA activation and tumor cell invasion in ovarian cancer SKOV-3 cells.

Promotion of functioning of human periodontal ligament cells and human endothelial cells by nerve growth factor.

BACKGROUND: We have previously shown that cultured human periodontal ligament (HPL) cells produce nerve growth factor (NGF) and express mRNA of tyrosine kinase receptor (trkA), a high-affinity receptor of NGF. These findings suggest that NGF modulates the differentiation and proliferation of the periodontal ligament cells by paracrine and autocrine functions in vivo. Endothelial cells also express NGF and trkA. Therefore, NGF may regulate functions of periodontal ligament cells and endothelial cells during periodontal tissue regeneration. METHODS: Effects of NGF on expressions of bone/cementum-related proteins (osteocalcin [OC], bone sialoprotein [BSP], bone morphogenetic protein [BMP-7], core binding factor alpha [Cbfa-1], and type I collagen), calcification in HPL cells, and proliferation and mRNA expression of vascular endothelial growth factor (VEGF), an endothelial cell mitogen, in human microvascular endothelial cells (HMVECs) were examined. RESULTS: NGF elevated mRNA levels of OC, BSP, BMP-7, Cbfa-1, and type I collagen and enhanced mineral deposition in cultures of HPL cells. Furthermore, NGF stimulated mRNA expressions of VEGF-A and VEGF-B and cell proliferation in HMVEC. CONCLUSION: These findings suggest that the functional regulation of periodontal ligament cells and endothelial cells by NGF might result in the acceleration of periodontal tissue regeneration in vivo.

[Intra-operative fluoroscopy for detecting pedicle screw violation in lumbar vertebrae by guided pin axial position].

OBJECTIVES: To develop an applicable and accurate intra-operative fluoroscopical angle to observe the placement of pedicle screw and pedicle violation. METHODS: Lateral radiographs were taken on eighty lumbar pedicles in eight cadaveric vertebral specimens to measure the sagittal pedicle angles. The pedicles of the vertebral arch were scanned by computed tomography (CT) to measure the transverse pedicle angles. Guided pins and pedicle screws were inserted by awl into the pedicles through the holes drilled in the lumbar pedicles so as to establish 3 types of model: medial violation (n = 29), lateral violation (n = 25), and properly placed screw (n = 26) the anterior and posterior portions of the lumbar pedicle cortex could be identified by the fluoroscopy C-arm. Fluoroscopy with the aid of C-arm was taken on each pedicle in five different directions: lateral position; anteroposterior position; pedicle axial position; guided pin axial position; and pedicle screw axial position. The positions of guided pin and pedicle screw were evaluated. The gold standard was acquired by excising the vertebral plate and observing directly. RESULTS: Nine cases of medial violation were discovered and the accuracy rate was 33.75% by anteroposterior fluoroscopy. The accuracy rate was 95% by the pedicle axial fluoroscopes, including 4 cases of medial inclination but properly placed screws were mistaken for medial violation by pedicle axial fluoroscope. The accuracy rate was 100% by guided pin axial position fluoroscopy, including 29 cases of medial violations, 25 cases of lateral violation, and 26 cases of properly placed screws. CONCLUSION: The approach of intra-operative fluoroscopy of guided pin axial position is a reliable technology for detecting pedicle violation with the aid of C-arm. The incidence of flexible pedicle screw from human factors can be reduced.

High GOLPH3 expression is associated with poor prognosis and invasion of hepatocellular carcinoma.

Golgi phosphoprotein 3 (GOLPH3) overexpression has previously been associated with the progression of several solid tumors, which resulted in adverse clinical outcomes. The present study aimed to determine the expression and prognostic significance of GOLPH3 in human hepatocellular carcinoma (HCC). GOLPH3 expression was examined using western blot analysis of 30 paired samples of HCC and adjacent non­cancerous liver tissues. GOLPH3 expression levels were also assessed using immunohistochemistry in 180 HCC samples and paired controls. In addition, the association of GOLPH3 expression with clinicopathological features and clinical outcome was analyzed. Furthermore, the effect of GOLPH3 on HCC cell proliferation and invasion were determined. Western blot analysis revealed that GOLPH3 expression was significantly elevated in HCC tissue compared with that of the matched adjacent non­cancerous liver tissue. In addition, the results of the immunohistochemical analysis demonstrated that GOLPH3 expression was positively correlated with the Edmondson­Steiner grade (P=0.006), vascular invasion (P=0.002) and serum α feto­protein levels (P=0.015). GOLPH3 expression was found to be an independent factor for predicting the poor overall survival of HCC patients (hazard ratio, 2.01; 95% confidence interval, 1.26­3.64; P=0.025). In addition, GOLPH3 silencing inhibited the proliferation, invasion and migration of HCC cell lines in vitro. In conclusion, the results of the present study demonstrated that high GOLPH3 levels may be a potential biomarker for the poor prognosis of patients with HCC.

[Surgical management of sacrococcygeal chordomas].

OBJECTIVE: To analyze the surgical treatment results of 52 patients with sacral chordoma. METHODS: This retrospective study included 52 cases of sacrococcygeal chordoma surgically treated from December 1996 to July 2001 at the Department of Orthopaedic Surgery, Peking University People's Hospital, The ages of patients ranged from 18 to 80 years (mean 57 years), including of 35 males and 17 females. Nineteen patients had received surgical management at least once and 9 of them had received radiation therapy, whereas the other 33 patients had no surgery before they came to our department. Posterior approach and combined anterior-posterior approach were used in 43 and 9 cases respectively. RESULTS: Based on a recent follow-up, 4 patients had died, and 3 of them died of metastatic chordoma. Among the other 46 patients who stayed alive, 35 were free from disease. The average follow-up time of the 35 disease-free patients was 42 months. In the 50 patients whose sacral nerve roots had been reserved bilaterally at and above S3 level, the sphincter muscle function of bladder and bowl was good, whereas the function of sphincter muscle impaired in 2 patients with nerve roots reserved only at and above S1 level. To manage these 2 patients, indwelling bladder catheters were used, but colostomy had not been performed. Local recurrence was observed in 7 of the 33 patients (21%) with the first surgery, and in 5 of the other 19 patients with second or third surgery. CONCLUSION: Complete resection of tumor (radical surgery when possible) is the most effective way to manage sacrococcygeal chordomas. Postoperative adjuvant radiation therapy can reduce the tumor recurrence rate, but it also can cause troubles that would hinder further surgical managements. Even if the tumor is relatively huge and the upper resection margin is as high as at S1 or S2 level, the tumor can be removed successfully by posterior approach and the postoperative complications could be accepted. Though proper surgical procedures and adjuvant radiation can control the tumor locally, we have no optimal methods to prevent metastases from developing or to cure them when they are detected. One patient who developed metastases in lungs received chemotherapy, and good curative effect had been observed.

[The surgical management of sacral tumors].

OBJECTIVE: To investigate the way of sacral tumors surgical treatment. METHODS: This retrospective study included 119 cases of sacral tumors surgically treated from July, 1996 to December, 2001. The age of patients ranged from 18 to 80 years (mean 57 years), including of 72 male and 47 female. Out of the patients, there were 52 chordomas, 16 giant cell tumor, 5 neurofibroma, 23 metastases tumors, 9 myeloma, 2 osteoblastomas, 5 aneurysmal bone cysts, 3 osteosarcomas, 4 chondrosarcomas. Posterior approach and combined anterior-posterior approach were used in 83 and 36 cases respectively. Twenty-nine patients had received surgical management at least once and 16 of them had received radiation therapy before came to our department. RESULTS: Three patients died on the complication around the surgery. Most of the patients with metastases tumor or multiple myeloma died 1 to 3 years after the surgery. Out of three osteosarcoma patients, 2 died and one alive with tumor. Three chondrosarcoma patients died, and one alive with tumor. Out of 52 chordoma patients, 3 patients had died of metastatic chordoma, 3 patients died of many times recurrence. Among the other 46 patients who were stay alive, 31 were free from disease with average follow-up time of 42 months. In the patients whose sacral nerve roots had been reserved bilaterally at and above S(3) level, the sphincter muscle function of bladder and bowl was good. While the function of sphincter muscle impaired in 2 patients with nerve roots reserved only at and above S(1) level. To manage these 2 patients, indwelling bladder catheters were used, but colostomy had not been performed. CONCLUSIONS: Complete resection of tumor (radical surgery when possible) is the most effective way to manage sacral tumors. Postoperative adjuvant radiation therapy can reduce the tumor recurrence rate, but it also can cause troubles that would hinder further surgical managements. Even if the tumor is relatively huge and the upper resection margin is as high as at S(1) or S(2) level, the tumor can be removed successfully by posterior approach and the postoperative complications could be accepted. To the patients with aneurysmal cyst or giant cell tumor on sacrum, for control bleeding purpose, anterior approach should be performed to ligate the bilateral internal iliac artery.

Sphingosine 1-phosphate (S1P) promotes mitochondrial biogenesis in Hep G2 cells by activating Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α).

Sphingosine 1-phosphate (S1P), a potent bioactive phospholipid, has been reported to regulate a broad spectrum of biological processes. However, little is known regarding S1P's effects on mitochondrial function. In this study, we investigated the S1P's effects on the Peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) signaling pathway and mitochondrial biogenesis in Hep G2 cells. Our results indicate that administration of S1P leads to a significant upregulation of mitochondrial DNA replication and transcription, increased mitochondrial mass, and elevated adenosine triphosphate synthesis. In addition, we found that treatment with S1P stimulates expression of PGC-1α, a master regulator of mitochondrial biogenesis, as well as its downstream targets: nuclear respiratory factor 1 (NRF1) and mitochondrial transcription factor A (TFAM). Moreover, our data demonstrate that S1P's effects on PGC-1α and mitochondrial biogenesis are mediated by the protein kinase A/cAMP response element-binding protein (PKA/CREB) pathway. Importantly, we also revealed that S1P's effects on mitochondrial biogenesis are dependent on its type 2 receptor (S1P2), though not on either its type 1 (S1P1) or type 3 (S1P3) receptors. Based on these observations, we concluded that S1P activates the PKA/CREB pathway through S1P2, which then promotes expression of PGC-1α/NRF1/TFAM and subsequent mitochondrial biogenesis in Hep G2 cells.

A novel function for lysyl oxidase in pluripotent mesenchymal cell proliferation and relevance to inflammation-associated osteopenia.

Lysyl oxidase is a multifunctional enzyme required for collagen biosynthesis. Various growth factors regulate lysyl oxidase during osteoblast differentiation, subject to modulation by cytokines such as TNF-α in inflammatory osteopenic disorders including diabetic bone disease. Canonical Wnt signaling promotes osteoblast development. Here we investigated the effect of Wnt3a and TNF-α on lysyl oxidase expression in pluripotent C3H10T1/2 cells, bone marrow stromal cells, and committed osteoblasts. Lysyl oxidase was up-regulated by a transcriptional mechanism 3-fold in C3H10T1/2 cells, and 2.5-fold in bone marrow stromal cells. A putative functional TCF/LEF element was identified in the lysyl oxidase promoter. Interestingly, lysyl oxidase was not up-regulated in committed primary rat calvarial- or MC3T3-E1 osteoblasts. TNF-α down-regulated lysyl oxidase both in Wnt3a-treated and in non-treated C3H10T1/2 cells by a post-transcriptional mechanism mediated by miR203. Non-differentiated cells do not produce a collagen matrix; thus, a novel biological role for lysyl oxidase in pluripotent cells was investigated. Lysyl oxidase shRNAs effectively silenced lysyl oxidase expression, and suppressed the growth of C3H10T1/2 cells by 50%, and blocked osteoblast differentiation. We propose that interference with lysyl oxidase expression under excess inflammatory conditions such as those that occur in diabetes, osteoporosis, or rheumatoid arthritis can result in a diminished pool of pluripotent cells which ultimately contributes to osteopenia.

Study on anti-tumor effect of total glycosides from Radix paeoniae rubra in S180 tumor-bearing mice.

The objective of the paper was to study the anti-tumor effect of total glycosides from Radix paeoniae rubra in S180 tumor-bearing mice, and to preliminarily explore its mechanism of action. Mice were made into S180 solid tumor model, grouped and administered with the extracts; tumor inhibition rate was measured by harvesting the tumors, and serum IL-2 and IL-4 levels were measured by taking blood samples. Total glycosides of Radix paeoniae rubra significantly inhibited the growth of tumor cells in tumor-bearing organisms, enhanced the cytotoxic activity of NK cells, and increased the serum IL-2 and IL-4 levels. Total glycosides of Radix paeoniae rubra have some anti-tumor effect in vivo, which might have been accomplished through the regulation of the immune system.

Accurately shaped tooth bud cell-derived mineralized tissue formation on silk scaffolds.

Based on the successful use of silk scaffolds in bone tissue engineering, we examined their utility for mineralized dental tissue engineering. Four types of hexafluoroisopropanol (HFIP) silk scaffolds-(250 and 550 microm diameter pores, with or without arginine-glycine-aspartic acid (RGD) peptide) were seeded with cultured 4-day postnatal rat tooth bud cells and grown in the rat omentum for 20 weeks. Analyses of harvested implants revealed the formation of bioengineered mineralized tissue that was most robust in 550 microm pore RGD-containing scaffolds and least robust in 250 microm pore sized scaffolds without RGD. The size and shape of the silk scaffold pores appeared to guide mineralized tissue formation, as revealed using polarized light imaging of collagen fiber alignment along the scaffold surfaces. This study is the first to characterize bioengineered tissues generated from tooth bud cells seeded onto silk scaffolds and indicates that silk scaffolds may be useful in forming mineralized osteodentin of specified sizes and shapes.

Effect of neurotrophins on differentiation, calcification and proliferation in cultures of human pulp cells.

Neurotrophins (NTs) are expressed during tooth development. However, little is known about a role of NTs in differentiation of pulp cells into mineralizing cells. In this study, mRNA expressions of hard tissue-related proteins, calcification and proliferation are examined in cultures of human pulp (HP) cells. Nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin (NT)-3 and NT-4/5 increased the mRNA levels of dentin sialophsphoprotein, alkaline phosphatase, osteopontin, type I collagen and bone morphogenetic protein-2 and mineral deposition in cultures of HP cells. The increased levels and manners varied, depending on the concentrations of NTs and hard-tissue related protein tested. On the other hand, only NGF significantly stimulated DNA synthesis in cultures of HP cells. These findings suggest that NTs characteristically regulate hard-tissue related protein expression, calcification and proliferation in pulp cells. NTs may accelerate pulp cell differentiation.

Characterization of epithelial cells derived from periodontal ligament by gene expression patterns of bone-related and enamel proteins.

The cells of epithelial rests of Malassez (ERM) are thought to play a number of roles, such as protection against root resorption and cementoblast differentiation. However, little is known about characteristics of these cells. In the present study, we compared the expression patterns of the bone-related proteins osteopontin (OPN), osteonectin/secreted protein, acidic and rich in cysteine (SPARC), osteoprotegerin (OPG), bone morphogenetic proteins (BMP-2 and BMP-4) and the enamel matrix proteins amelogenin and tuftelin in epithelial cells derived from human periodontal ligament (ECHPL) with those of human gingival epithelial cells (HGEC) and oral mesenchymal cells (human gingival fibroblasts, human periodontal ligament fibroblasts and human pulp cells). The mRNA expression patterns were determined by the reverse-transcription polymerase chain reaction (RT-PCR). Cytokeratin 8 mRNA was expressed by oral epithelial cells but not oral mesenchymal cells. The OPN mRNA levels in ECHPL were by far the highest in the five cell types investigated. ECHPL and oral mesenchymal cells expressed OPG mRNA, whereas HGEC did not. BMP-2, SPARC and tuftelin mRNAs were detected in ECHPL and the other cells examined. The oral mesenchymal cells expressed BMP-4 mRNA much more strongly than did the oral epithelial cells. Amelogenin mRNA expression could not be detected in any of the cells. These findings suggest that cultured ERM cells are characterized by expression of the cytokeratin 8, OPG and OPN genes.

Selective uptake and efflux of cholesteryl linoleate in LDL by macrophages expressing 12/15-lipoxygenase.

Oxidation of low density lipoprotein (LDL) is a critical step for atherogenesis, and the role of the 12/15-lipoxygenase (12/15-LOX) as well as LDL receptor-related protein (LRP) expressed in macrophages in this process has been suggested. The oxygenation of cholesteryl linoleate in LDL by mouse macrophage-like J774A.1 cells overexpressing 12/15-LOX was inhibited by an anti-LRP antibody but not by an anti-LDL receptor antibody. When the cells were incubated with LDL double-labeled by [3H]cholesteryl linoleate and [125I]apoB, association with the cells of [3H]cholesteryl linoleate expressed as LDL protein equivalent exceeded that of [125I]apoB, indicating selective uptake of [3H]cholesteryl linoleate from LDL to these cells. An anti-LRP antibody inhibited the selective uptake of [3H]cholesteryl ester by 62% and 81% with the 12/15-LOX-expressing cells and macrophages, respectively. Furthermore, addition of LDL to the culture medium of the [3H]cholesteryl linoleate-labeled 12/15-LOX-expressing cells increased the release of [3H]cholesteryl linoleate to the medium in LDL concentration- and time-dependent manners. The transport of [3H]cholesteryl linoleate from the cells to LDL was also inhibited by an anti-LRP antibody by 75%. These results strongly suggest that LRP contributes to the LDL oxidation by 12/15-LOX in macrophages by selective uptake and efflux of cholesteryl ester in the LDL particle.