Associations of meeting 24-h movement guidelines and metabolic syndrome in Korean adults during the COVID-19 pandemic

OBJECTIVES

This study aimed to investigate the association between adherence to 24-h movement guidelines and metabolic syndrome (MetS) before and during the COVID-19 pandemic.

STUDY DESIGN

Repeated cross-sectional design.

METHODS

We selected 10,882 adults (2019: n = 5710; 2020: n = 5172) aged ≥20 years from the Korea National Health and Nutrition Examination Survey. Domain-specific physical activity and sedentary behavior were assessed using a global physical activity questionnaire. We also measured the typical sleep duration (h/day) on weekdays and weekends. MetS was defined as the presence of more than three risk factors.

RESULTS

During the COVID-19 pandemic, transportation-related physical activity decreased, while the prevalence of abdominal obesity (+3.3 %) and low HDL-C levels (+3.1 %) increased significantly. An elevated risk of MetS was observed in the lower aerobic (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.04-1.58; P = 0.019) and muscular exercise (OR, 1.31; 95% CI, 1.04-1.66; P = 0.023) groups and in the high sedentary behavior (OR, 1.23; 95% CI, 1.00-1.51; P = 0.049) during the pandemic. Sensitivity analysis stratified by sex showed similar patterns with more pronounced changes in MetS components in males. The models also showed significant associations between aerobic physical activity, strength exercises, and sedentary behavior with MetS in males and females.

CONCLUSIONS

Although sedentary behavior and sleep time remained unchanged, a significant decrease in transportation-related physical activity was observed during the pandemic. Moreover, our findings revealed that aerobic physical activity, strength exercise, and sedentary time during the pandemic were associated with an increased MetS risk. These results highlight the importance of promoting physical activity, particularly during periods of social restriction, to mitigate the pandemic's negative effects on metabolic health.

[Differential proteomic screening of plasma exosomes before and after magnesium isoglycyrrhizinate treatment in chronic hepatitis B]

Objective: To screen the differential proteomic of plasma exosomes before and after magnesium isoglycyrrhizinate (MgIG) treatment in chronic hepatitis B patients. Methods: Plasma samples were collected from 36 cases with chronic hepatitis B before and after MgIG treatment (2 ml/case). Plasma exosomes were extracted by ultracentrifugation. Exosomal particles concentration and inner diameter were detected by Nanosight NS300 particle size analyzer. Three cases of plasma exosomes were randomly selected before and after MgIG treatment. Proteins were extracted after lysis and digested with trypsin. Label-free differential proteomics analysis was performed by liquid chromatography-tandem mass spectrometry to screen out differential proteins that changed more than 1.5 times. Enzyme linked immunosorbent assay (ELISA) was used to verify the quantitative differential protein expression (n = 30). Measurement data were compared by paired sample t-test. Results: The average particle concentration of the extracted exosomes was 2.2×10(9)/ml, and the average size was (107 ± 52) nm, which was consistent with the theoretical value of plasma exosome size, proving that the plasma exosomes were successfully extracted. Proteomics results showed that before and after MgIG treatment in chronic hepatitis B patients, a total of 153 differentially expressed proteins were screened, including 85 up-regulated and 68 down-regulated proteins. Enzyme-linked immunosorbent assay results showed that compared with the MgIG before and after treatment group of chronic hepatitis B patients, the differences in the concentrations of hepatocyte growth factor activator and hepatocyte growth factor like protein in plasma exosomes were statistically significant (P < 0.05). Hepatocyte growth factor activator concentration in the plasma exosomes before and after MgIG treatment group was (45.9 ± 9.4) μg/ml and (13.9 ± 2.0) μg/ml, respectively, and it was down-regulated by about 3 times. Hepatocyte growth factor-like protein concentration in the plasma exosomes before and after MgIG treatment group was (23.4 ± 4.9) μg/ml and (13.8 ± 2.2) μg/ml, respectively, and it was down-regulated by about 2 times. Enzyme-linked immunosorbent assay results had consistency with the proteomics results. Conclusion: This study successfully screened the differential proteomic of plasma exosomes before and after MgIG treatment in chronic hepatitis B, and provided experimental basis for studying the molecular mechanism of MgIG treatment for chronic hepatitis B.

[Clinical significance of ascitic interleukin-7 expression levels in cirrhotic patients complicated with spontaneous bacterial peritonitis]

Objective: To observe ascitic interleukin-7 expression level in cirrhotic patients complicated with spontaneous bacterial peritonitis, and to detect the effect of recombinant human IL-7 on CD4(+) and CD8(+)T lymphocyte function. Methods: A total of 84 patients with liver cirrhosis who were hospitalized from August 2017 to April 2018 were selected. Among them, 51 cases were complicated with cirrhosis and untainted ascites, and 33 cases were cirrhosis complicated with spontaneous bacterial peritonitis. Peripheral blood and ascites were collected routinely. The levels of IL-7 in peripheral blood and ascites were measured by enzyme-linked immunosorbent assay. CD4(+)T cells and CD8(+)T cells were purified from ascites, and were stimulated with recombinant IL-7. Cellular proliferation, key transcription factors for mRNA, and cytokines production by CD4(+)T cells in response to IL-7 stimulation was measured. mRNA expression corresponding to perforin, granzyme B, and granulysin as well as cytokines production by CD8(+)T cells was also measured in response to IL-7 stimulation. Cytolytic and non-cytolytic activity of CD8(+)T cells in response to IL-7 stimulation was also investigated in both direct and indirect contact co-culture system. Measurement data of the normal distribution were compared between the two groups by Student's t-test and the data before and after stimulation were compared by paired t-test. Measurements that did not conform to normal distribution were compared between the two groups using Mann-Whitney U test, and data before and after stimulation were compared using Wilcoxon paired test. Results: There was no significant statistical difference in serum IL-7 levels between the two groups [(5 001 ± 1 458) pg/ml vs. (4 768 ± 1 128) pg/ml, P = 0.41]. The level of ascitic IL-7 in cirrhotic patients complicated with SBP was significantly lower than cirrhosis patients with untainted ascites [(966.4 + 155.8) pg/ml vs. (792.1 + 126.4) pg/ml, P < 0.01]. Recombinant IL-7 stimulation promoted the proliferation of CD4(+) and CD8(+)T cells from ascites in patients with liver cirrhosis complicated by SBP. T-bet mRNA relative expression and IFN-γ secretion in CD4(+)T cells was also elevated in response to IL-7 stimulation in vitro. Moreover, IL-7 stimulation also increased the mRNA expressions of perforin, granzyme B, and granulysin as well as productions of IFN-γ and TNF-α by CD8(+)T cells. Recombinant IL-7 stimulation elevated cytolytic and non-cytolytic activity of CD8(+)T cells from ascites in patients with liver cirrohosis complicated by SBP, which manifested as increased target cell death and IFN-γ production in both direct and indirect contact co-culture system. Conclusion: Ascitic IL-7 promotes T lymphocyte function in patients with liver cirrhosis complicated with SBP.

Circ-ITCH regulates triple-negative breast cancer progression through the Wnt/β-catenin pathway

Recent studies indicate that circular RNA (circRNA) is involved in tumorigenesis, but its role in triple-negative breast cancer (TNBC) remains largely unknown. In this study, we characterized the role of circ-ITCH in TNBC and found that circ-ITCH was significantly down-regulated in TNBC tissues and cell lines and closely associated with poor prognosis. We therefore constructed the MDA-MB-231 and BT-549 TNBC cell lines stably expressing circ-ITCH by lentiviral vectors to determine its underlying mechanisms in TNBC progression. Most importantly, over-expression of circ-ITCH remarkably inhibited TNBC proliferation, invasion and metastasis both in vitro and in vivo. Mechanistically, we found that circ-ITCH acts as a sponge for miR-214 and miR-17 to increase expression of its ITCH linear isoform, thereby inactivating Wnt/β-catenin signaling. Our combined results show for the first time that circ-ITCH is a tumor suppressor, a promising prognostic biomarker in TNBC and that its restoration could well be a successful strategy in TNBC.

Increased glucose metabolism and alpha-glucosidase inhibition in Cordyceps militaris water extract-treated HepG2 cells

BACKGROUND/OBJECTIVES

Recent living condition improvements, changes in dietary habits, and reductions in physical activity are contributing to an increase in metabolic syndrome symptoms including diabetes and obesity. Through such societal developments, humankind is continuously exposed to metabolic diseases such as diabetes, and the number of the victims is increasing. This study investigated Cordyceps militaris water extract (CMW)-induced glucose uptake in HepG2 cells and the effect of CMW treatment on glucose metabolism.

MATERIALS/METHODS

Colorimetric assay kits were used to determine the glucokinase (GK) and pyruvate dehydrogenase (PDH) activities, glucose uptake, and glycogen content. Either RT-PCR or western blot analysis was performed for quantitation of glucose transporter 2 (GLUT2), hepatocyte nuclear factor 1 alpha (HNF-1α), phosphatidylinositol 3-kinase (PI3k), protein kinase B (Akt), phosphorylated AMP-activated protein kinase (pAMPK), phosphoenolpyruvate carboxykinase, GK, PDH, and glycogen synthase kinase 3 beta (GSK-3β) expression levels. The α-glucosidase inhibitory activities of acarbose and CMW were evaluated by absorbance measurement.

RESULTS

CMW induced glucose uptake in HepG2 cells by increasing GLUT2 through HNF-1α expression stimulation. Glucose in the cells increased the CMW-induced phosphorylation of AMPK. In turn, glycolysis was stimulated, and glyconeogenesis was inhibited. Furthermore, by studying the mechanism of action of PI3k, Akt, and GSK-3β, and measuring glycogen content, the study confirmed that the glucose was stored in the liver as glycogen. Finally, CMW resulted in a higher level of α-glucosidase inhibitory activity than that from acarbose.

CONCLUSION

CMW induced the uptake of glucose into HepG2 cells, as well, it induced metabolism of the absorbed glucose. It is concluded that CMW is a candidate or potential use in diabetes prevention and treatment.

Lipid-lowering effects of Zanthoxylum schinifolium Siebold & Zucc. seed oil (ZSO) in hyperlipidemic rats and lipolytic effects in 3T3-L1 adipocytes

On the basis of the antiatherosclerotic effect of Zanthoxylum schinifolium, the therapeutic potential of Zanthoxylum schinifolium seed oil (ZSO) was tested in terms of the blood lipid profile and obesity in rats. The lipolytic effects of ZSO were determined in adipocytes and the total body and liver weight were decreased in rats. Compared with the high-cholesterol high-fat (HCHF) group, the rats in the HCHF+ZSO group showed improved levels of hyperlipidemia indicators. Furthermore, western blot analysis confirmed that the improvement of hyperlipidemia indicators was induced by stimulation of lipoprotein lipase expression. Additional results indicated that the reduction in body weight was likely caused by phosphorylation of hormone-sensitive lipase (HSL) via the protein kinase A pathway, ultimately leading to lipolysis. In conclusion, the results of the in vivo experiment showed that ZSO improved the lipid profiles in the blood, lowering cardiovascular disease and arteriosclerosis and degrading cellular lipids by activating HSL.

Antiobesity effects of the water-soluble fraction of the ethanol extract of Smilax china L. leaf in 3T3-L1 adipocytes

BACKGROUND/OBJECTIVES

Several medicinal properties of Smilax china L. have been studied including antioxidant, anti-inflammatory, and anti-cancer effects. However, the antiobesity activity and mechanism by which the water-soluble fraction of this plant mediates its effects are not clear. In the present study, we investigated the lipolytic actions of the water-soluble fraction of Smilax china L. leaf ethanol extract (wsSCLE) in 3T3-L1 adipocytes.

MATERIALS/METHODS

The wsSCLE was identified by measuring the total polyphenol and flavonoid content. The wsSCLE was evaluated for its effects on cell viability, lipid accumulation, glycerol, and cyclic adenosine monophosphate (cAMP) contents. In addition, western blot analysis was used to evaluate the effects on protein kinase A (PKA), PKA substrates (PKAs), and hormone-sensitive lipase (HSL). For the lipid accumulation assay, 3T3-L1 adipocytes were treated with different doses of wsSCLE for 9 days starting 2 days post-confluence. In other cell experiments, mature 3T3-L1 adipocytes were treated for 24 h with wsSCLE.

RESULTS

Results showed that treatment with wsSCLE at 0.05, 0.1, and 0.25 mg/mL had no effect on cell morphology and viability. Without evidence of toxicity, wsSCLE treatment decreased lipid accumulation compared with the untreated adipocyte controls as shown by the lower absorbance of Oil Red O stain. The wsSCLE significantly induced glycerol release and cAMP production in mature 3T3-L1 cells. Furthermore, protein levels of phosphorylated PKA, PKAs, and HSL significantly increased following wsSCLE treatment.

CONCLUSION

These results demonstrate that the potential antiobesity activity of wsSCLE is at least in part due to the stimulation of cAMP-PKA-HSL signaling. In addition, the wsSCLE-stimulated lipolysis induced by the signaling is mediated via activation of the β-adrenergic receptor.

Cinnamyl alcohol attenuates vasoconstriction by activation of K⁺ channels via NO-cGMP-protein kinase G pathway and inhibition of Rho-kinase

Cinnamyl alcohol (CAL) is known as an antipyretic, and a recent study showed its vasodilatory activity without explaining the mechanism. Here we demonstrate the vasodilatory effect and the mechanism of action of CAL in rat thoracic aorta. The change of tension in aortic strips treated with CAL was measured in an organ bath system. In addition, vascular strips or human umbilical vein endothelial cells (HUVECs) were used for biochemical experiments such as Western blot and nitrite and cyclic guanosine monophosphate (cGMP) measurements. CAL attenuated the vasoconstriction of phenylephrine (PE, 1 µM)-precontracted aortic strips in an endothelium-dependent manner. CAL-induced vasorelaxation was inhibited by pretreatment with N^G-nitro-L-arginine methyl ester (L-NAME; 10^-4 M), methylene blue (MB; 10^-5 M) and 1 H-[1,2,4]-oxadiazolole-[4,3-a] quinoxalin-10one, (ODQ; 10^-6 or 10^-7 M) in the endothelium-intact aortic strips. Atrial natriuretic peptide (ANP; 10^-8 or 10^-9 M) did not affect the vasodilatory effect of CAL. The phosphorylation of endothelial nitric oxide synthase (eNOS) and generation of nitric oxide (NO) were stimulated by CAL treatment in HUVECs and inhibited by treatment with L-NAME. In addition, cGMP and PKG1 activation in aortic strips treated with CAL were also significantly inhibited by L-NAME. Furthermore, CAL relaxed Rho-kinase activator calpeptin-precontracted aortic strips, and the vasodilatory effect of CAL was inhibited by the ATP-sensitive K⁺ channel inhibitor glibenclamide (Gli; 10^-5 M) and the voltage-dependent K⁺ channel inhibitor 4-aminopyridine (4-AP; 2 × 10^-4 M). These results suggest that CAL induces vasorelaxation by activating K⁺ channels via the NO-cGMP-PKG pathway and the inhibition of Rho-kinase.

Synthesis of substituted cinnamoyl-tyramine derivatives and their platelet anti-aggregatory activities

Substituted cinnamoyl-tyramine derivatives were synthesized by DCC-coupling of substituted cinnamic acid with tyramine or tyramine methyl-1-ether to evaluate PAF-receptor binding antagonistic activities and inhibitory activities on PAF-induced platelet aggregation with interest on structure-activity relations. The results show that 3,4-dimethoxy-cinnamoyl tyramine-amide or its methyl ether have significant PAF-receptor binding antagonistic activity and platelet anti-aggregatory activities.

Visual pathway-related horizontal reference plane for three-dimensional craniofacial analysis

OBJECTIVES

To construct three-dimensional (3D) horizontal reference planes based on visual pathway and to determine their stability and reliability by analyzing the structural patterns of normal and dysmorphology for 3D craniofacial analysis.

SETTING AND SAMPLE POPULATION

Thirty-six subjects with maxillofacial dysmorphology and malocclusion, and eight normal controls. MATERIALS AND METHODS POPULATION: On the 3D computed tomographic images of the subjects, the visual pathway-based planes, including the orbital axis plane (OAP), visual axis plane (VAP), and the optical axis plane (OpAP), were constructed and evaluated.

RESULTS

The OAP, but not the VAP and OpAP, showed the ideal relationship between the midsagittal and posterior maxillary plane, and properly described the different patterns of maxillofacial dysmorphology with craniofacial plane 1 of Delaire's analysis and the occlusal plane.

CONCLUSIONS

The proposed visual pathway-related horizontal reference planes, and in particular the OAP, seem to correctly express the visual axis and the position of the head in natural head position and can be used as a horizontal reference plane for the 3D analysis of craniofacial dysmorphology and anthropology.

Vasodilatory effects of cinnamic acid via the nitric oxide-cGMP-PKG pathway in rat thoracic aorta

Cinnamic acid (CA) and its derivatives have a broad therapeutic spectrum that includes antimicrobial, antifungal, and antitumoral activities. However, the vasodilative effect of CA has not been demonstrated. The present study characterizes the vasodilative activity and the mechanism of CA in rat thoracic aorta. The vasomotion of aortic strips following CA treatment was measured in an organ bath system. In addition, vascular strips and human umbilical vein endothelial cells (HUVECs) were used in organ bath, Western blot, nitrite, and cyclic guanosine monophosphate (cGMP) measurements. CA relaxed phenylephrine-precontracted aortic strips in an endothelium-dependent manner. Pretreatment of the endothelium-intact aortic strips with N(G) -nitro-l-arginine methyl ester (10(-4)  M), 1 H-[1,2,4]-oxadiazolole-[4,3-a] quinoxalin-10-one, (10(-6)  M) and methylene blue (10(-5)  M) inhibited CA-induced vasorelaxation. CA also increased the phosphorylation of endothelial nitric oxide synthase and nitric oxide generation in a concentration-dependent manner in HUVECs. In addition, cGMP generation and cGMP-dependent protein kinase G (PKG) expression in aortic strips were increased by CA treatment. Furthermore, CA-induced vasorelaxation was inhibited by the PKG inhibitor KT5823 (0.3 μM) and the Ca(2+) -activated K(+) channel inhibitor tetraethylammonium (10(-3)  M). These findings suggest that CA exerts an endothelium-dependent vasodilation effect via the nitric oxide-cGMP-PKG-mediated pathway in rat thoracic aorta.

Vasorelaxant effect of Cinnamomi ramulus ethanol extract via rho-kinase signaling pathway

The Rho-kinase (ROCK) signaling pathway is substantially involved in vascular contraction. This study investigated the vasodilatory effects and possible mechanisms of Cinnamomi ramulus ethanol extract (CRE), with the hypothesis that the CRE vasodilatory effect involves RhoA and the ROCK signaling pathway in rat aortic preparations. CRE (0.05-1 mg/ml) dose-dependently relaxed the vascular contraction induced by phenylephrine and calpeptin in an endothelium-independent manner. Measurement of the expression levels of ROCK-related signaling molecules in response to calpeptin revealed that CRE completely inhibited RhoA and ROCK2 protein expressions. Furthermore, CRE dephosphorylated the subsequent downstream targets myosin phosphatase targeting subunit 1 (MYPT-1), protein kinase C potentiated phosphatase inhibitor protein-17 kDa (CPI-17) and myosin light chain 20 kDa (MLC20). We conclude that the vasorelaxation effect of CRE occurs via downregulation of ROCK signal molecules.

Stockholm Convention organochlorine pesticides and polycyclic aromatic hydrocarbons in Hong Kong air

Organochlorine pesticides (OCPs) including eight of the original nine pesticides listed in the Stockholm Convention on Persistent Organic Pollutants, and polycyclic aromatic hydrocarbons (PAHs) were measured in 90 air samples collected from January 2004 to March 2005, and in 304 air samples collected from January 1998 to December 2005 in Hong Kong, respectively. The annual average OCP concentrations at Tap Mun, Yuen Long and Tsuen Wan were 135+/-140 (ND-482), 186+/-183 (ND-656), and 190+/-239 fg m(-3) (ND-966), respectively, while annual (January 1998 to December 2005) average concentrations of total PAHs at Tsuen Wan, and Central/Western were 578+/-261 (117-938) and 588+/-248ngm(-3) (103-874), respectively. No seasonal and spatial variations in OCP concentrations were observed due to trace levels, and estimation of carcinogenic risks of OC pesticides was low. Naphthalene (>70%) was the dominant PAH in terms of concentrations measured. The sum of three-ring PAHs, including acenaphthene, acenaphthylene, anthracene, fluorene and phenanthrene, contributed to around 20% of the total PAH concentration while the contribution of heavier PAHs (sum of four-, five- and six-rings) was less than 5%. t-Values of the paired samples T-test for the individual PAHs showed that the concentrations of benzo(a)pyrene, the relative high cancer risk PAH, and most of the PAHs detected at Tsuen Wan and Central/Western were significantly different (p<0.01), with higher concentrations detected at Tsuen Wan. Several PAHs exhibited strong seasonality with higher concentrations in winter. Sources of PAHs were determined by investigating PAH isomer ratios which suggested petrogenic sources as primary sources of PAHs in Hong Kong air.

Functional analysis of the stress-inducible soybean calmodulin isoform-4 (GmCaM-4) promoter in transgenic tobacco plants

The transcription of soybean (Glycine max) calmodulin isoform-4 (GmCaM-4) is dramatically induced within 0.5 h of exposure to pathogen or NaCl. Core cis-acting elements that regulate the expression of the GmCaM-4 gene in response to pathogen and salt stress were previously identified, between -1,207 and -1,128 bp, and between -858 and -728 bp, in the GmCaM-4 promoter. Here, we characterized the properties of the DNA-binding complexes that form at the two core cis-acting elements of the GmCaM-4 promoter in pathogen-treated nuclear extracts. We generated GUS reporter constructs harboring various deletions of approximately 1.3-kb GmCaM-4 promoter, and analyzed GUS expression in tobacco plants transformed with these constructs. The GUS expression analysis suggested that the two previously identified core regions are involved in inducing GmCaM-4 expression in the heterologous system. Finally, a transient expression assay of Arabidopsis protoplasts showed that the GmCaM-4 promoter produced greater levels of GUS activity than did the CaMV35S promoter after pathogen or NaCl treatments, suggesting that the GmCaM-4 promoter may be useful in the production of conditional gene expression systems.

AtBAG6, a novel calmodulin-binding protein, induces programmed cell death in yeast and plants

Calmodulin (CaM) influences many cellular processes by interacting with various proteins. Here, we isolated AtBAG6, an Arabidopsis CaM-binding protein that contains a central BCL-2-associated athanogene (BAG) domain. In yeast and plants, overexpression of AtBAG6 induced cell death phenotypes consistent with programmed cell death (PCD). Recombinant AtBAG6 had higher affinity for CaM in the absence of free Ca2 + than in its presence. An IQ motif (IQXXXRGXXXR, where X denotes any amino-acid) was required for Ca2 +-independent CaM complex formation and single amino-acid changes within this motif abrogated both AtBAG6-activated CaM-binding and cell death in yeast and plants. A 134-amino-acid stretch, encompassing both the IQ motif and BAG domain, was sufficient to induce cell death. Agents generating oxygen radicals, which are known to be involved in plant PCD, specifically induced the AtBAG6 transcript. Collectively, these results suggest that AtBAG6 is a stress-upregulated CaM-binding protein involved in plant PCD.

Cytokinesis regulator ECT2 changes its conformation through phosphorylation at Thr-341 in G2/M phase

The Rho activator ECT2 functions as a key regulator in cytokinesis. ECT2 is phosphorylated during G2/M phase, but the physiological significance of this event is not well known. In this study, we show that phosphorylation of ECT2 at threonine-341 (T341) affects the autoregulatory mechanism of ECT2. In G2/M phase, ECT2 was phosphorylated at T341 most likely by Cyclin B/Cyclin-dependent kinase 1 (Cdk1), and then dephosphorylated before cytokinesis. Depletion of ECT2 by RNA interference (RNAi) efficiently induced multinucleate cells. Expression of the phospho-deficient mutant of ECT2 at T341 suppressed the multinucleation induced by RNAi to ECT2, indicating that ECT2 is biologically active even when it is not phosphorylated at T341. However, the phospho-mimic mutation at T341 weakly stimulates the catalytic activity of ECT2 as detected by serum response element reporter gene assays. As T341 is located at the hinge region of the N-terminal regulatory domain and C-terminal catalytic domain, phosphorylation of T341 may help accessing downstream signaling molecules to further activate ECT2. We found that the phospho-mimic mutation T341D increases binding with itself or the N-terminal half of ECT2. These results suggest a conformational change of ECT2 upon phosphorylation at T341. Therefore, ECT2 activity might be regulated by the phosphorylation status of T341. We propose that T341 phosphorylation by Cyclin B/Cdk1 could be a trigger for further activation of ECT2.

Arabidopsis ubiquitin-specific protease 6 (AtUBP6) interacts with calmodulin

Calmodulin (CaM), a key Ca(2+) sensor in eukaryotes, regulates diverse cellular processes by interacting with many proteins. To identify Ca(2+)/CaM-mediated signaling components, we screened an Arabidopsis expression library with horseradish peroxidase-conjugated Arabidopsis calmodulin2 (AtCaM2) and isolated a homolog of the UBP6 deubiquitinating enzyme family (AtUBP6) containing a Ca(2+)-dependent CaM-binding domain (CaMBD). The CaM-binding activity of the AtUBP6 CaMBD was confirmed by CaM mobility shift assay, phosphodiesterase competition assay and site-directed mutagenesis. Furthermore, expression of AtUBP6 restored canavanine resistance to the Deltaubp6 yeast mutant. This is the first demonstration that Ca(2+) signaling via CaM is involved in ubiquitin-mediated protein degradation and/or stabilization in plants.

WRKY group IId transcription factors interact with calmodulin

Calmodulin (CaM) is a ubiquitous Ca(2+)-binding protein known to regulate diverse cellular functions by modulating the activity of various target proteins. We isolated a cDNA encoding AtWRKY7, a novel CaM-binding transcription factor, from an Arabidopsis expression library with horseradish peroxidase-conjugated CaM. CaM binds specifically to the Ca(2+)-dependent CaM-binding domain (CaMBD) of AtWRKY7, as shown by site-directed mutagenesis, a gel mobility shift assay, a split-ubiquitin assay, and a competition assay using a Ca2+/CaM-dependent enzyme. Furthermore, we show that the CaMBD of AtWRKY7 is a conserved structural motif (C-motif) found in group IId of the WRKY protein family.

Direct interaction of a divergent CaM isoform and the transcription factor, MYB2, enhances salt tolerance in arabidopsis

Calmodulin (CaM), a ubiquitous calcium-binding protein, regulates diverse cellular functions by modulating the activity of a variety of enzymes and proteins. Plants express numerous CaM isoforms that exhibit differential activation and/or inhibition of CaM-dependent enzymes in vitro. However, the specific biological functions of plant CaM are not well known. In this study, we isolated a cDNA encoding a CaM binding transcription factor, MYB2, that regulates the expression of salt- and dehydration-responsive genes in Arabidopsis. This was achieved using a salt-inducible CaM isoform (GmCaM4) as a probe from a salt-treated Arabidopsis expression library. Using domain mapping, we identified a Ca2+-dependent CaM binding domain in MYB2. The specific binding of CaM to CaM binding domain was confirmed by site-directed mutagenesis, a gel mobility shift assay, split ubiquitin assay, and a competition assay using a Ca2+/CaM-dependent enzyme. Interestingly, the specific CaM isoform GmCaM4 enhances the DNA binding activity of AtMYB2, whereas this was inhibited by a closely related CaM isoform (GmCaM1). Overexpression of Gm-CaM4 in Arabidopsis up-regulates the transcription rate of AtMYB2-regulated genes, including the proline-synthesizing enzyme P5CS1 (Delta1-pyrroline-5-carboxylate synthetase-1), which confers salt tolerance by facilitating proline accumulation. Therefore, we suggest that a specific CaM isoform mediates salt-induced Ca2+ signaling through the activation of an MYB transcriptional activator, thereby resulting in salt tolerance in plants.

Pathogen- and NaCl-induced expression of the SCaM-4 promoter is mediated in part by a GT-1 box that interacts with a GT-1-like transcription factor

The Ca(2+)-binding protein calmodulin mediates cellular Ca(2+) signals in response to a wide array of stimuli in higher eukaryotes. Plants express numerous CaM isoforms. Transcription of one soybean (Glycine max) CaM isoform, SCaM-4, is dramatically induced within 30 min of pathogen or NaCl stresses. To characterize the cis-acting element(s) of this gene, we isolated an approximately 2-kb promoter sequence of the gene. Deletion analysis of the promoter revealed that a 130-bp region located between nucleotide positions -858 and -728 is required for the stressors to induce expression of SCaM-4. A hexameric DNA sequence within this region, GAAAAA (GT-1 cis-element), was identified as a core cis-acting element for the induction of the SCaM-4 gene. The GT-1 cis-element interacts with an Arabidopsis GT-1-like transcription factor, AtGT-3b, in vitro and in a yeast selection system. Transcription of AtGT-3b is also rapidly induced within 30 min after pathogen and NaCl treatment. These results suggest that an interaction between a GT-1 cis-element and a GT-1-like transcription factor plays a role in pathogen- and salt-induced SCaM-4 gene expression in both soybean and Arabidopsis.

Regulation of the Dual Specificity Protein Phosphatase, DsPTP1, through Interactions with Calmodulin

Reversible phosphorylation is a key mechanism for the control of intercellular events in eukaryotic cells. In animal cells, Ca2+/CaM-dependent protein phosphorylation and dephosphorylation are implicated in the regulation of a number of cellular processes. However, little is known on the functions of Ca2+/CaM-dependent protein kinases and phosphatases in Ca2+ signaling in plants. From an Arabidopsis expression library, we isolated cDNA encoding a dual specificity protein phosphatase 1, which is capable of hydrolyzing both phosphoserine/threonine and phosphotyrosine residues of the substrates. Using a gel overlay assay, we identified two Ca2+-dependent CaM binding domains (CaMBDI in the N terminus and CaMBDII in the C terminus). Specific binding of CaM to two CaMBD was confirmed by site-directed mutagenesis, a gel mobility shift assay, and a competition assay using a Ca2+/CaM-dependent enzyme. At increasing concentrations of CaM, the biochemical activity of dual specificity protein phosphatase 1 on the p-nitrophenyl phosphate (pNPP) substrate was increased, whereas activity on the phosphotyrosine of myelin basic protein (MBP) was inhibited. Our results collectively indicate that calmodulin differentially regulates the activity of protein phosphatase, dependent on the substrate. Based on these findings, we propose that the Ca2+ signaling pathway is mediated by CaM cross-talks with a protein phosphorylation signal pathway in plants via protein dephosphorylation.

Liposome-complexed adenoviral gene transfer in cancer cells expressing various levels of coxsackievirus and adenovirus receptor

PURPOSE

Loss of coxsackievirus and adenovirus receptor (CAR) is frequently observed in malignant cancer, hampering adenoviral gene therapy approaches. Complexing adenovirus with cationic liposomes can increase adenoviral transgene expression, particularly in cells with CAR-deficiency. We investigated whether other factors such as lipid composition might be involved in determining the efficiency of liposome-complexed adenoviral gene transfer in cancer cells.

MATERIAL AND METHODS

Human cancer cell lines with different expression levels of CAR were infected with a GFP transgene. The efficiency of transgene expression was assessed by determining GFP expression using FACS analysis.

RESULTS

The efficiency of liposome-complexed adenoviral gene transfer was dependent on the lipid composition constituting liposomes. Polyethylene glycol (PEG)-containing liposomes were most effective in increasing liposome-complexed adenoviral gene transfer. In CAR-deficient cells, use of PEG-containing liposomes enhanced adenoviral gene transfer, whereas in CAR-expressing cells enhancement varied depending on cell type. In some CAR-expressing cells, the effect of liposome complexing was even comparable to that in CAR-deficient cells. Increased adenoviral transgene expression following complexing with PEG-containing liposomes correlated with liposome uptake in cancer cells.

CONCLUSIONS

Liposome-complexed adenoviral gene transfer appears to depend on lipid composition and the level of liposome uptake by cancer cells, in addition to CAR levels. Our study suggest that these multiple factors should be considered in designing liposome-complexed adenoviral vectors to improve outcomes of current adenoviral cancer gene therapies.

Elevated levels of circulating platelet microparticles, VEGF, IL-6 and RANTES in patients with gastric cancer: possible role of a metastasis predictor

The activation of coagulation, angiogenesis and inflammatory cytokines are considered to be related with tumour growth and metastasis. We investigated the plasma levels of platelet microparticles (PMP), vascular endothelial growth factor (VEGF), IL-6, and the chemokine RANTES in patients with gastric cancer (n=109) and in healthy controls (n=29). The plasma levels of PMP, IL-6 and RANTES were significantly higher in the patients than in the healthy controls, and plasma levels of PMP, VEGF, IL-6 and RANTES were significantly higher in patients with stage IV disease than those in patients with stage I or stage II/III. In terms of predicting distant metastasis, the sensitivities of PMP, VEGF, IL-6 and RANTES were 93.3%, 56.7%, 70.0% and 81.8%, respectively, and the corresponding specificities were 91.1%, 64.6%, 79.7% and 50.0%. Among these parameters, PMP had the highest diagnostic accuracy. Significant correlations were found between PMP, VEGF, IL-6 and RANTES. This study demonstrates that the plasma levels of PMP, VEGF, IL-6 and RANTES were markedly increased in patients with stage IV disease, and that these increased plasma levels of IL-6, RANTES, and especially PMP, might be useful for identifying metastatic gastric patients.

Characterization of a stamen-specific cDNA encoding a novel plant defensin in Chinese cabbage

We isolated a stamen-specific cDNA, BSD1 (Brassica stamen specific plant defensin 1) that encodes a novel plant defensin peptide in Chinese cabbage (Brassica campestris L. ssp. pekinensis). Plant defensins are antimicrobial peptides containing eight highly conserved cysteine residues linked by disulfide bridges. In BSD1, the eight cysteine residues and a glutamate residue at position 29 are conserved whereas other amino acid residues of the plant defensins consensus sequence are substituted. BSD1 transcripts accumulate specifically in the stamen of developing flowers and its level drops as the flowers mature. The recombinant BSD1 produced in Escherichia coli showed antifungal activity against several phytopathogenic fungi. Furthermore, constitutive over-expression of the BSD1 gene under the control of the cauliflower mosaic virus (CaMV) 35S promoter conferred enhanced tolerance against the Phytophthora parasitica in the transgenic tobacco plants.

Mlo, a modulator of plant defense and cell death, is a novel calmodulin-binding protein. Isolation and characterization of a rice Mlo homologue

Transient influx of Ca(2+) constitutes an early event in the signaling cascades that trigger plant defense responses. However, the downstream components of defense-associated Ca(2+) signaling are largely unknown. Because Ca(2+) signals are mediated by Ca(2+)-binding proteins, including calmodulin (CaM), identification and characterization of CaM-binding proteins elicited by pathogens should provide insights into the mechanism by which Ca(2+) regulates defense responses. In this study, we isolated a gene encoding rice Mlo (Oryza sativa Mlo; OsMlo) using a protein-protein interaction-based screening of a cDNA expression library constructed from pathogen-elicited rice suspension cells. OsMlo has a molecular mass of 62 kDa and shares 65% sequence identity and scaffold topology with barley Mlo, a heptahelical transmembrane protein known to function as a negative regulator of broad spectrum disease resistance and leaf cell death. By using gel overlay assays, we showed that OsMlo produced in Escherichia coli binds to soybean CaM isoform-1 (SCaM-1) in a Ca(2+)-dependent manner. We located a 20-amino acid CaM-binding domain (CaMBD) in the OsMlo C-terminal cytoplasmic tail that is necessary and sufficient for Ca(2+)-dependent CaM complex formation. Specific binding of the conserved CaMBD to CaM was corroborated by site-directed mutagenesis, a gel mobility shift assay, and a competition assay with a Ca(2+)/CaM-dependent enzyme. Expression of OsMlo was strongly induced by a fungal pathogen and by plant defense signaling molecules. We propose that binding of Ca(2+)-loaded CaM to the C-terminal tail may be a common feature of Mlo proteins.

Synthetic low-calcaemic vitamin D(3) analogues inhibit secretion of insulin-like growth factor II and stimulate production of insulin-like growth factor-binding protein-6 in conjunction with growth suppression of HT-29 colon cancer cells

The aims of the present study were to compare the ability of various synthetic analogues of 1 alpha,25-dihydroxyvitamin D(3) [1 alpha,25-(OH)(2)D(3)] to inhibit proliferation of HT-29 cells, a human colon adenocarcinoma cell line. HT-29 cells were incubated for 144 h with various concentrations (0-100 nM) of 1 alpha,25-(OH)(2)D(3), or the analogues EB1089, CB1093 or 1 beta,25-(OH)(2)D(3). All these analogues except 1 beta,25-(OH)(2)D(3) inhibited cell proliferation, but relative potencies and efficacies of EB1089 and CB1093 were much greater than that of the native vitamin. Cells grew in serum-free medium, reaching a plateau density at day 10 of culture, and addition of 10 nM 1 alpha,25-(OH)(2)D(3) or 1 beta,25-(OH)(2)D(3) did not alter the long-term growth characteristics of HT-29 cells. However, cells treated with 10 nM EB1089 or CB1093 grew at a rate slower than control and reached final densities that were 53+/-1 and 36+/-2% lower than control, respectively. Immunoblot analysis of serum-free conditioned medium using a monoclonal anti-insulin-like growth factor-(IGF)-II antibody showed that both 10 nM EB1089 and CB1093 markedly inhibited secretion of both mature 7500 M(r) and higher M(r) forms of IGF-II. Ligand blot and immunoblot analyses of conditioned media revealed the presence of IGFBPs of M(r) 24,000 (IGFBP-4), 30,000 (glycosylated IGFBP-4), 35,000 (IGFBP-2) and 32,000-34,000 (IGFBP-6). The level of IGFBP-2 was decreased by 42+/-8 and 49+/-7% by 10 nM EB 1089 and CB1093, respectively, compared to controls. IGFBP-6 was increased approximately twofold by EB1089 and CB1093, and exogenously added IGFBP-6 inhibited HT-29 cell proliferation. These results suggest that inhibition of HT-29 cell proliferation by EB1089 and CB1093 may be attributed, at least in part, to the decreased secretion of IGF-II. The increase in IGFBP-6 concentration coupled with its high affinity for IGF-II may also contribute to decreased cellular proliferation by an indirect mechanism involving sequestration of endogenously produced IGF-II.

Antimetastatic and antitumor effects of benzoquinonoid AC7-1 from Ardisia crispa

An antimetastatic and cytostatic substance, termed AC7-1, was isolated from Ardisia crispa and identified as a benzoquinonoid compound, 2-methoxy-6-tridecyl-1,4-benzoquinone. It was originally characterized as the potent PAF (platelet-activating factor) receptor-binding antagonist with nonspecific antiplatelet effects on platelet aggregation induced by various agonists including PAF, ADP, thrombin and collagen. The nonspecific antiaggregatory properties of AC7-1 drew our interest given its possible relationship in integrin receptor-binding antagonistic activity. The integrin receptor plays an important role in metastasis and thrombosis as the cell surface transmembrane protein. Based on the aforementioned facts, the antimetastatic activities of AC7-1 were examined using various in vitro and in vivo metastasis assays. AC7-1 strongly blocked B16-F10 melanoma cell adhesion to extracellular matrix (ECM) and B16-F10 melanoma cell invasion. AC7-1 also remarkably inhibited pulmonary metastasis and tumor growth in vivo. AC7-1 inhibited B16-F10 melanoma cell adhesion to only specific synthetic peptides including RGDS. These findings suggest that antimetastatic activities of AC7-1 can be caused by blocking integrin-mediated adherence. We found AC7-1 to be a potential candidate for the development of a new antimetastatic drug.

Ca(2+) influx and cAMP elevation overcame botulinum toxin A but not tetanus toxin inhibition of insulin exocytosis

Previous reports showed that cleavage of vesicle-associated membrane protein-2 (VAMP-2) and synaptosomal-associated protein of 25 kDa (SNAP-25) by clostridial neurotoxins in permeabilized insulin-secreting beta-cells inhibited Ca(2+)-evoked insulin secretion. In these reports, the soluble N-ethylmaleimide-sensitive factor attachment protein target receptor proteins might have formed complexes, which preclude full accessibility of the putative sites for neurotoxin cleavage. In this work, VAMP-2 and SNAP-25 were effectively cleaved before they formed toxin-insensitive complexes by transient transfection of insulinoma HIT or INS-1 cells with tetanus toxin (TeTx) or botulinum neurotoxin A (BoNT/A), as shown by immunoblotting and immunofluorescence microscopy. This resulted in an inhibition of Ca(2+) (glucose or KCl)-evoked insulin release proportionate to the transfection efficiency (40-50%) and an accumulation of insulin granules. With the use of patch-clamp capacitance measurements, Ca(2+)-evoked exocytosis by membrane depolarization to -10 mV was abolished by TeTx (6% of control) but only moderately inhibited by BoNT/A (30% of control). Depolarization to 0 mV to maximize Ca(2+) influx partially overcame BoNT/A (50% of control) but not TeTx inhibition. Of note, cAMP activation potentiated Ca(2+)-evoked secretion by 129% in control cells but only 55% in BoNT/A-transfected cells and had negligible effects in TeTx-transfected cells. These results indicate that, whereas VAMP-2 is absolutely necessary for insulin exocytosis, the effects of SNAP-25 depletion on exocytosis, perhaps on insulin granule pool priming or mobilization steps, could be partially reversed by higher levels of Ca(2+) or cAMP potentiation.

The relationship between microvessel count and the expression of vascular endothelial growth factor, p53, and K-ras in non-small cell lung cancer

Using immunohistochemical staining, we studied the relationship between the microvessel count (MC) and the expression of K-ras, mutant p53 protein, and vascular endothelial growth factor (VEGF) in 61 surgically resected non-small cell lung cancers (NSCLC) (42 squamous cell carcinoma, 14 adenocarcinoma, 2 large cell carcinoma, 2 adenosquamous carcinoma, and 1 mucoepidermoid carcinoma). MC of the tumors with lymph node (LN) metastasis was significantly higher than that of tumors without LN metastasis (66.1+/-23.1 vs. 33.8+/-13.1, p<0.05). VEGF was positive in 54 patients (88.5%). MC was 58.1+/-25.2 (mean+/-S.D.) in a x200 field, and it was significantly higher in VEGF(+) tumors than in VEGF(-) tumors (61.4+/-23.7 vs. 32.9+/-23.8, p<0.05). VEGF expression was higher in K-ras-positive or mutant p53-positive tumors than in negative tumors (p<0.05). MC was significantly higher in K-ras(+) tumors than in K-ras(-) tumors, although it did not differ according to the level of mutant p53 protein expression. Survival did not differ with VEGF, mutant p53, or K-ras expression, or the level of MC. In conclusion, there is a flow of molecular alterations from K-ras and p53, to VEGF expression, leading to angiogenesis and ultimately lymph node metastasis. Correlations between variables in close approximation and the lack of prognostic significance of individual molecular alterations suggest that tumorigenesis and metastasis are multifactorial processes.

Altered expression and mutation of beta-catenin gene in gastric carcinomas and cell lines

beta-catenin serves not only as a structural component of the E-cadherin-mediated cell-cell adhesion system, but also as a signaling molecule of the Wnt/wingless pathway. Deregulated expression of beta-catenin and mutations of the gene have been identified in a number of human malignancies. To determine the role of beta-catenin defects in stomach cancer, we investigated beta-catenin exon 3 mutations and altered protein expression in 77 primary gastric carcinomas and 11 cell lines. In addition, the immunohistochemical expression pattern of beta-catenin in 303 consecutive gastric cancers was determined and their relationships with clinicopathologic features and patient outcome were investigated. This study revealed 5% (4 of 77) tumors and 27% (3 of 11) cell lines with beta-catenin gene alteration, 6 missense mutations, and 1 interstitial deletion. These genetic changes were shown to correlate closely with nuclear localization of the protein (p = 0.001). In an immunohistochemical analysis, abnormal expressions of beta-catenin, such as nuclear accumulation and loss of membranous distribution, were detected in 27% (81 of 303) of tumors overall. These altered beta-catenin expressions were more commonly observed in 37% (58 of 158) diffuse type gastric carcinomas (p < 0.001). Loss of membranous beta-catenin staining was associated with poor survival (p = 0.045). In conclusion, our results demonstrate that beta-catenin mutations are common in gastric cancer cell lines but occur infrequently in gastric carcinoma tissues. These mutations are one of the causes of the nuclear accumulation of beta-catenin. Frequent abnormalities of beta-catenin expression in gastric carcinoma support the idea that both structural and signaling functions of the protein play a critical role in gastric carcinogenesis.

Altered expression and mutation of beta-catenin gene in gastric carcinomas and cell lines

beta-catenin serves not only as a structural component of the E-cadherin-mediated cell-cell adhesion system, but also as a signaling molecule of the Wnt/wingless pathway. Deregulated expression of beta-catenin and mutations of the gene have been identified in a number of human malignancies. To determine the role of beta-catenin defects in stomach cancer, we investigated beta-catenin exon 3 mutations and altered protein expression in 77 primary gastric carcinomas and 11 cell lines. In addition, the immunohistochemical expression pattern of beta-catenin in 303 consecutive gastric cancers was determined and their relationships with clinicopathologic features and patient outcome were investigated. This study revealed 5% (4 of 77) tumors and 27% (3 of 11) cell lines with beta-catenin gene alteration, 6 missense mutations, and 1 interstitial deletion. These genetic changes were shown to correlate closely with nuclear localization of the protein (p = 0.001). In an immunohistochemical analysis, abnormal expressions of beta-catenin, such as nuclear accumulation and loss of membranous distribution, were detected in 27% (81 of 303) of tumors overall. These altered beta-catenin expressions were more commonly observed in 37% (58 of 158) diffuse type gastric carcinomas (p < 0.001). Loss of membranous beta-catenin staining was associated with poor survival (p = 0.045). In conclusion, our results demonstrate that beta-catenin mutations are common in gastric cancer cell lines but occur infrequently in gastric carcinoma tissues. These mutations are one of the causes of the nuclear accumulation of beta-catenin. Frequent abnormalities of beta-catenin expression in gastric carcinoma support the idea that both structural and signaling functions of the protein play a critical role in gastric carcinogenesis.

Intramitochondrial pyruvate attenuates hydrogen peroxide-induced apoptosis in bovine pulmonary artery endothelium

In the hydrogen peroxide (H2O2) apoptosis model of the murine thymocyte, redox reactant and antioxidant pyruvate prevents programmed cell death. We tested the hypothesis that such protection was mediated, at least in part, via pyruvate handling by mitochondrial metabolism. Cultured bovine pulmonary artery endothelial cells were incubated for 30 min with 0.5 mM H2O2 in the absence and presence of 0.5 mM alpha-cyano-3-hydroxycinnamate, as a selective inhibitor of the mitochondrial pyruvate transporter. In controls H2O2 decreased cell viability by 30% within 24 h; this was associated with apoptosis-like bodies, nuclear condensation, and biochemical DNA damage consistent with programmed cell death. Pyruvate (0.1-20 mM) enhanced cell viability in a dose-dependent manner, with > or = 85% viable cells at > or = 3 mM and no DNA laddering, no positive nick-end labeling (TUNEL), and no detectable Annexin V or propidium iodide staining. In contrast, using > or = 5 mM L-lactate as a cytosolic reductant or acetate as a redox-neutral substrate, cell death increased to approximately 40%, which was associated with intense DNA laddering, positive TUNEL and Hoechst 33258 assays. Alpha-cyano-3-hydroxycinnamate alone did not significantly decrease endothelial viability but reduced viability from 85+/-3 to 71+/-4% (p = 0.023) in presence of 3 mM pyruvate plus H2O2; pathological cell morphology and DNA laddering under the same conditions suggested loss of pyruvate protection against apoptosis. Since alpha-cyano-3-hydroxycinnamate re-distributed medium pyruvate and L-lactate consistent with selective blockade of pyruvate uptake into the mitochondria, the findings support the hypothesis that pyruvate protection against H2O2 apoptosis is mediated in part via the mitochondrial matrix compartment. Possible mediators include anti-apoptotic bcl-2 and/or products of mitochondrial pyruvate metabolism such as citrate that affect metabolic regulation and anti-oxidant status in the cytoplasm.

Precoating of ultrahigh molecular weight polyethylene with polymethylmethacrylate: interfacial strength

Fixation of polymeric implants, especially an ultrahigh molecular weight polyethylene (UHMWPE) acetabular cup, to a host bone site has been a challenge since its first conception from the Charnley low friction total hip arthroplasty. Destabilization of the acetabular cup, similar to the well-documented cases of femoral stems, is caused mainly by aseptic loosening; the mobile loosened particles further contribute to the progression of aseptic loosening. Although the obvious fixation problems lie in the bone-bone cement interface, little work has been done to reduce the loosening by improving the acetabular components as a whole in cemented procedures. Most of the grooved outer surface, external fixation devices, and metal backings have been introduced to avoid problematic fixation of the cup to bone cement; nevertheless, the designs themselves to some degree became the source of the loosening problems. One possible way to improve the adhesion of acrylic bone cement to the UHMWPE acetabular cup is precoating the surface with polymethylmethacrylate (PMMA). This study successfully precoated the UHMWPE surface with PMMA, showing good chemical and mechanical stability, and suggests the optimal conditions of variables involved in the newly developed precoating process. The highest interfacial tensile strength was 11.51 +/- 0.65 MPa, which is stronger than those of UHMWPE and metal in metal-backed cups (6.3 MPa) and bone-bone cement (8.5 MPa). Further chemical analysis and mechanical testing are in progress, yet the present result of the mechanical tensile strength test showed that the precoating process for the UHMWPE surface could be a viable means toward stable fixation of the polymeric implants by using PMMA bone cement.