Defects in a liver-bone axis contribute to hepatic osteodystrophy disease progression.

Hepatic osteodystrophy (HOD) is a metabolic bone disease that is often associated with chronic liver disease and is marked by bone loss. Here, we demonstrate that hepatic expression of the phosphatase PP2Acα is upregulated during HOD, leading to the downregulation of expression of the hepatokine lecithin-cholesterol acyltransferase (LCAT). Loss of LCAT function markedly exacerbates the bone loss phenotype of HOD in mice. In addition, we found that alterations in cholesterol levels are involved in the regulation of osteoblast and osteoclast activities. We also found that LCAT improves liver function and relieves liver fibrosis in the mouse HOD model by promoting reversal of cholesterol transport from the bone to the liver. In summary, defects in a liver-bone axis occur during HOD that can be targeted to ameliorate disease progression.

HSC-specific knockdown of GGPPS alleviated CCl4-induced chronic liver fibrosis through mediating RhoA/Rock pathway.

Hepatic stellate cells (HSCs) play a critical role in the pathogenesis and reversal of liver fibrosis. Targeting HSCs is of great significance in the treatment of hepatic fibrosis, and has attracted wide attention of scholars. Here we demonstrated that expression of geranylgeranyldiphosphate synthase (GGPPS) predominantly increased in HSCs in murine fibrotic liver. HSC-specific knockdown of GGPPS using vitamin A-coupled liposome carrying siRNA-ggpps decreased activation of HSCs and alleviated fiber accumulation in vivo. Furthermore, our in vitro studies showed that GGPPS was up-regulated during HSCs activation in TGF-ß1-dependent manner. Inhibition of GGPPS suppressed TGF-ß1 induced F-actin reorganization and HSCs activation in LX-2 cells. Further, we found that GGPPS regulated HSCs activation and liver fibrosis possibly by enhancing RhoA/Rock kinase signaling. So its concluded that GGPPS promotes liver fibrosis by activating HSCs, which may represent a potential target for anti-fibrosis therapies.

Egr1 deficiency disrupts dynamic equilibrium of chondrocyte extracellular matrix through PPARγ/RUNX2 signaling pathways.

BACKGROUND: This study is to investigate the effect of Egr1 on the mineralization and accumulation of chondrocyte extracellular matrix. METHODS: The femoral heads of patients of various heights were collected. Egr1 knockout mice were used. Their limb lengtha nd body weight were assessed. The bone characteristics were detected by micro-CT scan and histological staining. Immature murine articular chondrocytes (iMACs) were isolated. Gross morphology was observed by histological staining. Relevant mRNA and protein expression were detected by qRT-PCR and Western blot, respectively. the related proteins were observed by immunohistochemical staining and immunofluorescence assay. Chromatin immunoprecipitation and reporter gene assay were also used. TUNEL was used to detect apoptosis. RESULTS: It was found that shorter patients had reduced Egr1 expression levels in the hypertrophic cartilage zone of the femoral head. In addition, Egr1 knockout mice exhibited reduced body size. Micro-CT analysis showed that these mice also had reduced bone volume. Safranin-O staining showed that the extracellular matrix of these mice exhibited a relatively limited degree of mineralization, and TUNEL staining showed reduced cell apoptosis levels. After transfecting the iMACs with dominant-negative Egr1 adenoviruses to inhibit Egr1, the enzymes of Adamst4, Adamst5, Mmp3 and Mmp13 were significantly upregulated. ChIP and luciferase assays revealed that Egr1 might regulate the chondrocyte extracellular matrix by the PPARγ/RUNX2 signaling pathways. CONCLUSION: Egr1 has an important regulatory effect on the dynamic equilibrium of the chondrocyte extracellular matrix, which may be achieved through the PPARγ/RUNX2 signaling pathways.

Inhibition effect of siRNA-downregulated UHRF1 on breast cancer growth.

The UHRF1 gene plays important roles in both cell proliferation through its NIRF_N domains, a PHD domain, an SRA domain, and a RING domain, and multidrug resistance in breast cancer treatment. In this work, a short-hairpin RNA (shRNA) lentiviral system was introduced in two human breast cancer cell lines (MDA-MB-231 and MCF-7) to downregulate the expression of UHRF1 and study the specific inhibition of UHRF1 in breast cancer growth. The effect of UHRF1-shRNA on breast cancer cell proliferation was examined using methylthiazoletetrazolium, bromodeoxyuridine, and colony formation assays. The proliferative potential of the UHRF1-shRNA-treated cells showed a remarkable decrease. Moreover, the downregulation of UHRF1 in both breast cancer cell lines significantly inhibited the colony formation capacity. Results suggested that the inhibition of UHRF1 via an RNA interference lentiviral system may provide an effective way for breast cancer therapy.

Electrochemical antitumor drug sensitivity test for leukemia K562 cells at a carbon-nanotube-modified electrode.

The change in electrochemical behavior of tumor cells induced by antitumor drugs was detected by using a multiwall carbon nanotubes (MWNTs)-modified glass carbon electrode (GCE). Based on the changes observed, a simple, in vitro, electrochemical antitumor drug sensitivity test was developed. MWNTs promoted electron transfer between the electroactive centers of cells and the electrode. Leukemia K562 cells exhibited a well-defined anodic peak of guanine at +0.823 V at 50 mV s(-1). HPLC assay with ultraviolet detection was used to elucidate the reactant responsible for the electrochemical response of the tumor cells. The guanine content within the cytoplasm of each K562 cell was detected to be 920 amol. For the drug sensitivity tests, 5-fluorouracil (5-FU) and several clinical antitumor drugs, such as vincristine, adriamycin, and mitomycin C, were added to cell culture medium. As a result, the electrochemical responses of the K562 cells decreased significantly. The cytotoxicity curves and results obtained corresponded well with the results of MTT assays. In comparison to conventional methods, this electrochemical test is highly sensitive, accurate, inexpensive, and simple. The method proposed could be developed as a convenient means to study the sensitivity of tumor cells to antitumor drugs.

Three olefin copper(I) dimeric complexes with 2-, 3-, and 4-pyridylacrylic acid and their electrochemical properties.

UV irradiation of 2-, 3-, or 4-pyridylacrylic acid (2-, 3-, and 4-HPYA) with Cu(I)Cl at 230 nm in 4 N HCl for 1 week and subsequent hydrothermal reactions yielded three novel highly stable 3-D copper(I)-olefin dimers, [(2-H(2)PYA)(2)Cu(+)(2)Cl(4)](n)() (1), [(3-H(2)PYA)(2)Cu(+)(2)Cl(4)](n)() (2), and [(4-H(2)PYA)(2)Cu(+)(2)Cl(4)(I)](n)() (3), respectively, in which H-bonds play a key role in the stabilization of supramolecular Cu(I)-olefin system and thus the formation of the 3-D networks. The electrochemical properties of 1-3 are also reported.

[Flow injection chemiluminescent detection of acemetacin in KMnO4 - Na2 SO3 system].

AIM: To study the sensitizing effect of acemetacin (ACE) on the weak chemiluminescent (CL) reaction of KMnO4 with sulfite and establish a fast and convenient method for CL detection of ACE. METHODS: Using the sensitizing effect of ACE on KMnO4-Na2SO3 system and flow injection technique to determine the concentration of ACE. RESULTS: Under optimal conditions, the CL intensity of 1.0 x 10(-2) mol x L(-1) H3PO4 - 5.0 x 10(-5) mol x L(-1) KMnO4 - 4.0 x 10(-4) mol x L(-1) Na2SO3 was proportional to the concentration of ACE ranging from 1.0 x 10(-7) to 1.0 x 10(-5) mol x L(-1). The detection limit of ACE was 6.9 x 10(-8) mol x L(-1) at 3sigma. Satisfactory results were obtained for determination of ACE at 2.5 x 10(-6) mol x L(-1). CONCLUSION: The present method showed good precision, high sensitivity and selectivity and could be used for fast and convenient detection of ACE. It would be of significance to the clinical and pharmacological study of acemetacin.

Flow injection determination of papaverine based on its sensitizing effect on the chemiluminescence reaction of permanganate-sulfite.

A novel chemiluminescence (CL) method for the determination of papaverine (PAP) has been developed by combining the flow injection technique and its sensitizing effect on the weak CL reaction between sulfite and acidic permanganate. A mechanism for the CL reaction has been proposed on the basis of fluorescent and chemiluminescence spectra. The CL response is proportional to the concentration of PAP over the range 0.2-10 micro mol L(-1). The detection limit of PAP is 0.10 micro mol L(-1) (3 s) with a relative standard deviation (RSD) of 2.0% for 10 repetitive determinations of 1.0 micro mol L(-1) PAP. Interferences from other alkaloids in the opium, such as morphine and codeine, are negligible except that of narcotine. The method has been satisfactorily used for the determination of PAP in injections and compound liquorice tablets.

Hybridization biosensor using di(2,2'-bipyridine)osmium (III) as electrochemical indicator for detection of polymerase chain reaction product of hepatitis B virus DNA.

A novel hepatitis B virus (HBV) DNA biosensor was developed by immobilizing covalently single-stranded HBV DNA fragments to a gold electrode surface via carboxylate ester to link the 3(')-hydroxy end of the DNA with the carboxyl of the thioglycolic acid (TGA) monolayer. A short-stranded HBV DNA fragment (181bp) of known sequence was obtained and amplified by PCR. The surface hybridization of the immobilized single-stranded HBV DNA fragment with its complementary DNA fragment was evidenced by electrochemical methods using [Os(bpy)(2)Cl(2)](+) as a novel electroactive indicator. The formation of double-stranded HBV DNA on the gold electrode resulted in a great increase in the peak currents of [Os(bpy)(2)Cl(2)](+) in comparison with those obtained at a bare or single-stranded HBV DNA-modified electrode. The mismatching experiment indicated that the surface hybridization was specific. The difference between the responses of [Os(bpy)(2)Cl(2)](+) at single-stranded and double-stranded DNA/TGA gold electrodes suggested that the label-free hybridization biosensor could be conveniently used to monitor DNA hybridization with a high sensitivity. X-ray photoelectron spectrometry technique has been employed to characterize the immobilization of single-stranded HBV DNA on a gold surface.

Renewable reagentless hydrogen peroxide sensor based on direct electron transfer of horseradish peroxidase immobilized on colloidal gold-modified electrode.

A novel renewable reagentless hydrogen peroxide (H(2)O(2)) sensor based on the direct electron transfer of horseradish peroxidase (HRP) is proposed. The direct electrochemistry of HRP immobilized on a colloidal gold-modified carbon paste electrode (Au-CPE) was investigated using electrochemical methods. The immobilized HRP displayed a pair of redox peaks in 0.1M phosphate buffer (PB), pH 7.0, with a formal potential of -0.346 V. The response showed a surface-controlled electrode process with an electron transfer rate constant of 6.04+/-0.18s(-1) determined in the scan rate range from 120 to 500 mV/s. The biosensor displayed an excellent electrocatalytic response to the reduction of H(2)O(2) without the aid of an electron mediator. The sensor surface could be renewed quickly and reproducibly by a simple polish step. The calibration range of H(2)O(2) was 0-0.3mM with linear relation from 0.48 to 50 microM and a detection limit of 0.21 microM at 3 sigma. The response showed Michaelis-Menten behavior at higher H(2)O(2) concentrations. The K(app)(M) value of HRP at HRP-Au-CPE was determined to be 3.69+/-0.71 mM.