Alpha-crystallin-mediated protection of lens cells against heat and oxidative stress-induced cell death

In addition to their key role as structural lens proteins, α-crystallins also appear to confer protection against many eye diseases, including cataract, retinitis pigmentosa, and macular degeneration. Exogenous recombinant α-crystallin proteins were examined for their ability to prevent cell death induced by heat or oxidative stress in a human lens epithelial cell line (HLE-B3). Wild type αA- or αB-crystallin (WT-αA and WT-αB) and αA- or αB-crystallins, modified by the addition of a cell penetration peptide (CPP) designed to enhance the uptake of proteins into cells (gC-αB, TAT-αB, gC-αA), were produced by recombinant methods. In vitro chaperone-like assays were used to assay the ability of α-crystallins to protect client proteins from chemical or heat induced aggregation. In vivo viability assays were performed in HLE-B3 to determine whether pre-treatment with α-crystallins reduced death after exposure to oxidative or heat stress. Most of the five recombinant α-crystallin proteins tested conferred some in vitro protection from protein aggregation, with the greatest effect seen with WT-αB and gC-αB. All α-crystallins displayed significant protection to oxidative stress induced cell death, while only the αB-crystallins reduced cell death induced by thermal stress. Our findings indicate that the addition of the gC tag enhanced the protective effect of αB-crystallin against oxidative but not thermally-induced cell death. In conclusion, modifications that increase the uptake of α-crystallin proteins into cells, without destroying their chaperone-like activity and anti-apoptotic functions, create the potential to use these proteins therapeutically.     

Biological Characteristics of the MG-63 Human Osteosarcoma Cells on Composite Tantalum Carbide/Amorphous Carbon Films

Tantalum (Ta) is a promising metal for biomedical implants or implant coating for orthopedic and dental applications because of its excellent corrosion resistance, fracture toughness, and biocompatibility. This study synthesizes biocompatible tantalum carbide (TaC) and TaC/amorphous carbon (a-C) coatings with different carbon contents by using a twin-gun magnetron sputtering system to improve their biological properties and explore potential surgical implant or device applications. The carbon content in the deposited coatings was regulated by controlling the magnetron power ratio of the pure graphite and Ta cathodes. The deposited TaC and TaC/a-C coatings exhibited better cell viability of human osteosarcoma cell line MG-63 than the uncoated Ti and Ta-coated samples. Inverted optical and confocal imaging was used to demonstrate the cell adhesion, distribution, and proliferation of each sample at different time points during the whole culture period. The results show that the TaC/a-C coating, which contained two metastable phases (TaC and a-C), was more biocompatible with MG-63 cells compared to the pure Ta coating. This suggests that the TaC/a-C coatings exhibit a better biocompatible performance for MG-63 cells, and they may improve implant osseointegration in clinics.     

Chronic Hepatitis C Virus Infection Is Associated with the Development of Rheumatoid Arthritis: A Nationwide Population-Based Study in Taiwan

ObjectiveThe association between chronic hepatitis virus infection and rheumatoid arthritis (RA) remains debatable. This nationwide population-based cohort study assessed the risk of RA among patients with a chronic infection of hepatitis B and/or C virus.ResultsAfter adjusting for covariates, chronic HCV infection alone was significantly associated with an increased risk for RA (hazard ratio (HR)  = 2.03, 95% confidence interval (CI)  = 1.27–3.22). The increased risk for RA among participants with chronic HCV infection remained significant after restricting the analysis to those who were prescribed disease-modifying anti-rheumatic drugs. The corresponding HR for the overall sample was 1.89 (95% CI  = 1.15–3.11). However, HBV carriers did not appear to be at a significantly higher risk for RA.ConclusionOur data imply that chronic HCV infection is associated with RA development.     

Effect of red mold rice supplements on serum and meat cholesterol levels of broilers chicken

Monacolin K is a secondary metabolite produced by Monascus species. It was found that it is able to decrease cholesterol levels. In this study, red mold rice (RMR) was added to the diet of Arbor Acres broiler chickens, and the cholesterol level in meat, as well as the concentration of triglyceride, the high-density lipoprotein cholesterol (HDL-C), and the low-density lipoprotein cholesterol (LDL-C) in the serum were evaluated. Four-week-old broilers are studied and divided into four groups in that each group contains 15 subjects. A 3-week experimental feeding trial was conducted in which three groups of broilers were fed 2.0, 5.0, and 8.0% of RMR (RMR groups) within their diet, respectively, and the result was compared to the control group. The results indicated that for each RMR group, the cholesterol content was significantly lower than that of the control group; in addition, their meat products contain higher level of unsaturated fatty acids. Triglyceride and cholesterol concentration in serum was also found to be considerably lower in RMR groups when compared to control group. Finally, in RMR groups, HDL-C/LDL-C and HDL-C/cholesterol ratios were all higher than those of the control group. In short, the results demonstrated that the cholesterol levels could be lowered by adding RMR to the diet of chickens.     

Identification of the high affinity binding site in transforming growth factor-beta involved in complex formation with alpha 2-macroglobulin. Implications regarding the molecular mechanisms of complex formation between alpha 2-macroglobulin and growth factors, cytokines, and hormones

The biological activities of transforming growth factor-beta isoforms (TGF-beta(1,2)) are known to be modulated by alpha(2)-macroglobulin (alpha(2)M). alpha(2)M forms complexes with numerous growth factors, cytokines, and hormones, including TGF-beta. Identification of the binding sites in TGF-beta isoforms responsible for high affinity interaction with alpha(2)M many unravel the molecular basis of the complex formation. Here we demonstrate that among nine synthetic pentacosapeptides with overlapping amino acid sequences spanning the entire TGF-beta(1) molecule, the peptide (residues 41-65) containing Trp-52 exhibited the most potent activity in inhibiting the formation of complexes between (125)I-TGF-beta(1) and activated alpha(2)M (alpha(2)M*) as determined by nondenaturing polyacrylamide gel electrophoresis and by plasma clearance in mice. TGF-beta(2) peptide containing the homologous sequence and Trp-52 was as active as the TGF-beta(1) peptide, whereas the corresponding TGF-beta(3) peptide lacking Trp-52, was inactive. The replacement of the Trp-52 with alanine abolished the inhibitory activities of these peptides. (125)I-TGF-beta(3), which lacks Trp-52, bound to alpha(2)M* with an affinity lower than that of (125)I-TGF-beta(1). Furthermore, unlabeled TGF-beta(3) and the mutant TGF-beta(1)W52A, in which Trp-52 was replaced with alanine, were less potent than unlabeled TGF-beta(1) in blocking I(125)-TGF-beta(1) binding to alpha(2)M*. TGF-beta(1) and TGF-beta(2) peptides containing Trp-52 were also effective in inhibiting I(125)-nerve growth factor binding to alpha(2)M*. Tauhese results suggest that Trp-52 is involved in high affinity binding of TGF-beta to alpha(2)M*. They also imply that TGF-beta and other growth factors/cytokines/hormones may form complexes with alpha(2)M* via a common mechanism involving the interactions between topologically exposed Trp and/or other hydrophobic residues and a hydrophobic region in alpha(2)M*.     

Emodin-induced apoptosis through p53-dependent pathway in human hepatoma cells

Most of the commonly used cytotoxic anticancer drugs have been shown to induce apoptosis in susceptible cells. However, the signaling pathway of their apoptotic effects remains undefined. In this study, the cytotoxic effect of emodin on various human hepatoma cell lines was investigated. Results demonstrated that emodin exhibited strongly suppressing effect on HepG2/C3A, PLC/PRF/5, and SK-HEP-1 cells, with the IC(50) value of 42.5, 46.6, and 53.1 microM, respectively. Furthermore, emodin induced apoptosis in HepG2/C3A cells was clearly verified by the appearance of DNA fragmentation and sub-G(1) accumulation. Besides, HepG2/C3A cells were found to be arrested in G(2)/M phase after the cells were treated with 60 microM emodin for 48 h. Moreover, significant increase in the levels of apoptosis-related signals such as p53 (419.3 pg/ml), p21 (437.4 units/ml), Fas (6.6 units/ml), and caspase-3 (35.4 pmol/min) were observed in emodin treated HepG2/C3A cells. Taken together, emodin displays effective inhibitory effects on the growth of various human hepatoma cell lines and stimulates the expression of p53 and p21 that resulted in the cell cycle arrest of HepG2/C3A cells at G(2)/M phase. Results also suggest that emodin-induced apoptosis in HepG2/C3A cells were mediated through the activation of p53, p21, Fas/APO-1, and caspase-3. It implies that emodin could be a useful chemotherapeutical agent for treatment of hepatocellular carcinoma (HCC).     

Purification and characterization of human colony-stimulating factor 1 from human pancreatic carcinoma (MIA PaCa-2) cells

Colony-stimulating factor 1 (CSF-1) was purified from the serum-free conditioned medium of a human pancreatic carcinoma cell line (MIA PaCa-2) by a combination of conventional chromatography and high-performance liquid chromatography. The purity of human CSF-1 was demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) with a diffuse single band of Mr 42,000-50,000 and by N-terminal amino acid analysis of glutamate residue. The CSF-1 was stable at 50 degrees C for 30 min. It is sensitive to treatment with trypsin, chymotrypsin, and subtilisin but less sensitive to papain digestion. Treatment of CSF-1 with different glycosidases did not affect the biological activity. Sulfhydryl reagents such as dithiothreitol (DTT), iodoacetic acid, and N-ethylmaleimide did not affect the biological activity at the concentration of 1 mM. However, CSF-1 activity was inhibited totally by the combination of 10 mM DTT and 1 mM SDS. Under denaturing and reducing conditions, CSF-1 appeared on SDS-PAGE as a single protein band of Mr 21,000-25,000 and concurrently lost its activity, indicating that human CSF-1 possibly consists of two similar subunits and that the intact quaternary structure is essential for the biological activity. When treated with neuraminidase and endo-beta-D-N-acetylglucosaminidase D, the molecular weight of CSF-1 was reduced to 36,000-40,000, and to 18,000-20,000 in the presence of mercaptoethanol. Because of the specificity of endo-beta-D-N-acetylglucosaminidase D, it is suggested that the carbohydrate moieties are Asn-linked "complex-type" units.     

Lipopolysaccharide increases resistin gene expression in vivo and in vitro

Although resistin has been thought to be an important link between obesity and diabetes, recent results do not support this hypothesis. We speculated that resistin may be involved in inflammatory processes and be induced by inflammatory stimuli. In this study, we tested whether lipopolysaccharide (LPS) induced resistin expression in rats. The results show that resistin mRNA levels in white adipose tissue and white blood cells were increased by LPS treatment. LPS also increased resistin mRNA levels in 3T3-L1 adipocytes and human peripheral blood monocytes. The results suggest that resistin is involved in insulin resistance and probably in other inflammatory responses.