The phosphatidylinositol-glycolipid anchor on alkaline phosphatase facilitates mineralization initiation in vitro

2009 ◽  
Vol 10 (4) ◽  
pp. 568-573 ◽  
Author(s):  
Gerald Harrison ◽  
Irving M. Shapiro ◽  
Ellis E. Golub
Author(s):  
C. Jennermann ◽  
S. A. Kliewer ◽  
D. C. Morris

Peroxisome proliferator-activated receptor gamma (PPARg) is a member of the nuclear hormone receptor superfamily and has been shown in vitro to regulate genes involved in lipid metabolism and adipocyte differentiation. By Northern analysis, we and other researchers have shown that expression of this receptor predominates in adipose tissue in adult mice, and appears first in whole-embryo mRNA at 13.5 days postconception. In situ hybridization was used to find out in which developing tissues PPARg is specifically expressed.Digoxigenin-labeled riboprobes were generated using the Genius™ 4 RNA Labeling Kit from Boehringer Mannheim. Full length PPAR gamma, obtained by PCR from mouse liver cDNA, was inserted into pBluescript SK and used as template for the transcription reaction. Probes of average size 200 base pairs were made by partial alkaline hydrolysis of the full length transcripts. The in situ hybridization assays were performed as described previously with some modifications. Frozen sections (10 μm thick) of day 18 mouse embryos were cut, fixed with 4% paraformaldehyde and acetylated with 0.25% acetic anhydride in 1.0M triethanolamine buffer. The sections were incubated for 2 hours at room temperature in pre-hybridization buffer, and were then hybridized with a probe concentration of 200μg per ml at 70° C, overnight in a humidified chamber. Following stringent washes in SSC buffers, the immunological detection steps were performed at room temperature. The alkaline phosphatase labeled, anti-digoxigenin antibody and detection buffers were purchased from Boehringer Mannheim. The sections were treated with a blocking buffer for one hour and incubated with antibody solution at a 1:5000 dilution for 2 hours, both at room temperature. Colored precipitate was formed by exposure to the alkaline phosphatase substrate nitrobluetetrazoliumchloride/ bromo-chloroindlylphosphate.


Author(s):  
S.K. Aggarwal

The proposed primary mechanism of action of the anticancer drug cisplatin (Cis-DDP) is through its interaction with DNA, mostly through DNA intrastrand cross-links or DNA interstrand cross-links. DNA repair mechanisms can circumvent this arrest thus permitting replication and transcription to proceed. Various membrane transport enzymes have also been demonstrated to be effected by cisplatin. Glycoprotein alkaline phosphatase was looked at in the proximal tubule cells before and after cisplatin both in vivo and in vitro for its inactivation or its removal from the membrane using light and electron microscopy.Outbred male Swiss Webster (Crl: (WI) BR) rats weighing 150-250g were given ip injections of cisplatin (7mg/kg). Animals were killed on day 3 and day 5. Thick slices (20-50.um) of kidney tissue from treated and untreated animals were fixed in 1% buffered glutaraldehyde and 1% formaldehyde (0.05 M cacodylate buffer, pH 7.3) for 30 min at 4°C. Alkaline phosphatase activity and carbohydrates were demonstrated according to methods described earlier.


1994 ◽  
Vol 301 (2) ◽  
pp. 577-583 ◽  
Author(s):  
K Oda ◽  
J Cheng ◽  
T Saku ◽  
N Takami ◽  
M Sohda ◽  
...  

Placental alkaline phosphatase (PLAP) is initially synthesized as a precursor (proPLAP) with a C-terminal extension. We constructed a recombinant cDNA which encodes a chimeric protein (alpha GL-PLAP) comprising rat alpha 2u-globulin (alpha GL) and the C-terminal extension of PLAP. Two molecular species (25 kDa and 22 kDa) were expressed in the COS-1 cell transfected with the cDNA for alpha GL-PLAP. Only the 22 kDa form was labelled with both [3H]stearic acid and [3H]ethanolamine. Upon digestion with phosphatidylinositol-specific phospholipase C the 22 kDa form was released into the medium, indicating that this form is anchored on the cell surface via glycosylphosphatidylinositol (GPI). A specific IgG raised against a C-terminal nonapeptide of proPLAP precipitated the 25 kDa form but not the 22 kDa form, suggesting that the 25 kDa form is a precursor retaining the C-terminal propeptide. When a mutant alpha GL-PLAP, in which the aspartic acid residue is replaced with tryptophan at a putative cleavage/attachment site, was expressed in COS-1 cells, the 25 kDa precursor was the only form found inside the cell and retained in the endoplasmic reticulum, as judged by immunofluorescence microscopy. In vitro translation programmed with mRNAs coding for the wild-type and mutant forms of alpha GL-PLAP demonstrated that the C-terminal propeptide was cleaved from the wild-type chimeric protein, but not from the mutant one. This gave rise to the 22 kDa form attached with a GPI anchor, suggesting that GPI is covalently linked to the aspartic acid residue (Asp159) of alpha GL-PLAP. Taken together, these results indicate that the C-terminal propeptide of PLAP functions as a signal to render alpha GL a GPI-linked membrane protein in vitro and in vivo in cultured cells, and that the chimeric protein constructed in this study may be useful for elucidating the mechanism underlying the cleavage of the propeptide and attachment of GPI, which occur in the endoplasmic reticulum.


2015 ◽  
Vol 44 (4) ◽  
pp. 195-199 ◽  
Author(s):  
Priscilla Barbosa Ferreira Soares ◽  
Camilla Christian Gomes Moura ◽  
Huberth Alexandre da Rocha Júnior ◽  
Paula Dechichi ◽  
Darceny Zanetta-Barbosa

<title>Abstract</title><sec><title>Objective</title><p>Evaluate the biological performance of titanium alloys grade IV under different surface treatments: sandblasting and double etching (Experimental surface 1; Exp1, NEODENT); surface with wettability increase (Experimental surface 2; Exp2, NEODENT) on response of preliminary differentiation and cell maturation.</p></sec><sec><title>Material and method</title><p>Immortalized osteoblast cells were plated on Exp1 and Exp2 titanium discs. The polystyrene plate surface without disc was used as control group (C). Cell viability was assessed by measuring mitochondrial activity (MTT) at 4 and 24 h (n = 5), cell attachment was performed using trypan blue exclusion within 4 hours (n = 5), serum total protein and alkaline phosphatase normalization was performed at 4, 7 and 14 days (n = 5). Data were analyzed using one-way ANOVA and Tukey test.</p></sec><sec><title>Result</title><p>The values of cell viability were: 4h: C– 0.32±0.01<sup>A</sup>; Exp1– 0.34±0.08<sup>A</sup>; Exp2– 0.29±0.03<sup>A</sup>. 24h: C– 0.43±0.02<sup>A</sup>; Exp1– 0.39±0.01<sup>A</sup>; Exp2– 0.37±0.03<sup>A</sup>. The cell adhesion counting was: C– 85±10<sup>A</sup>; Exp1- 35±5<sup>B</sup>; Exp2– 20±2<sup>B</sup>. The amounts of serum total protein were 4d: C– 40±2<sup>B</sup>; Exp1– 120±10<sup>A</sup>; Exp2– 130±20<sup>A</sup>. 7d: C– 38±2<sup>B</sup>; Exp1– 75±4<sup>A</sup>; Exp2– 70±6<sup>A</sup>. 14 d: C– 100±3<sup>A</sup>; Exp1– 130±5<sup>A</sup>; Exp2– 137±9<sup>A</sup>. The values of alkaline phosphatase normalization were: 4d: C– 2.0±0.1<sup>C</sup>; Exp1– 5.1±0.8<sup>B</sup>; Exp2– 9.8±2.0<sup>A</sup>. 7d: C– 1.0±0.01<sup>C</sup>; Exp1– 5.3±0.5<sup>A</sup>; Exp2– 3.0±0.3<sup>B</sup>. 14 d: C– 4.1±0.3<sup>A</sup>; Exp1– 4.4±0.8<sup>A</sup>; Exp2– 2.2±0.2<sup>B</sup>. Different letters related to statistical differences.</p></sec><sec><title>Conclusion</title><p>The surfaces tested exhibit different behavior at dosage of alkaline phosphatase normalization showing that the Exp2 is more associated with induction of cell differentiation process and that Exp1 is more related to the mineralization process.</p></sec>


1952 ◽  
Vol 62 (1) ◽  
pp. 1-31 ◽  
Author(s):  
B. I. Balinsky

Synopsis:The early development of the mammary glands and of hair follicles in the mouse and the rabbit has been investigated by means of mitotic counts, by histochemical methods and by cultivation in vitro. In the first stage of the formation of both types of rudiment a thickening of the epidermis appears as a consequence of an aggregation of cells, not of a local elevation of the mitotic rate. During this stage alkaline phosphatase is absent from the cells and the content of ribose-nucleic acid reduced. Both these substances appear in higher concentrations later, and their relation to processes of growth and differentiation is discussed. Essentially similar phenomena are found in rudiments cultivated in vitro, which, however, frequently suffer a degeneration by a process of keratinisation.


Author(s):  
Kari Hanson ◽  
Carly Isder ◽  
Kristen Shogren ◽  
Anthony L. Mikula ◽  
Lichun Lu ◽  
...  

OBJECTIVE The use of intrawound vancomycin powder in spine surgery has been shown to decrease the rate of surgical site infections; however, the optimal dose is unknown. High-dose vancomycin inhibits osteoblast proliferation in vitro and may decrease the rate of solid arthrodesis. Bone marrow–derived mesenchymal stem cells (BMSCs) are multipotent cells that are a source of osteogenesis in spine fusions. The purpose of this study was to determine the effects of vancomycin on rat BMSC viability and differentiation in vitro. METHODS BMSCs were isolated from the femurs of immature female rats, cultured, and then split into two equal groups; half were treated to stimulate osteoblastic differentiation and half were not. Osteogenesis was stimulated by the addition of 50 µg/mL l-ascorbic acid, 10 mM β-glycerol phosphate, and 0.1 µM dexamethasone. Vancomycin was added to cell culture medium at concentrations of 0, 0.04, 0.4, or 4 mg/mL. Early differentiation was determined by alkaline phosphatase activity (4 days posttreatment) and late differentiation by alizarin red staining for mineralization (9 days posttreatment). Cell viability was determined at both the early and late time points by measurement of formazan colorimetric product. RESULTS Viability within the first 4 days decreased with high-dose vancomycin treatment, with cells receiving 4 mg/mL vancomycin having 40%–60% viability compared to the control. A gradual decrease in alizarin red staining and nodule formation was observed with increasing vancomycin doses. In the presence of the osteogenic factors, vancomycin did not have deleterious effects on alkaline phosphatase activity, whereas a trend toward reduced activity was seen in the absence of osteogenic factors when compared to osteogenically treated cells. CONCLUSIONS Vancomycin reduced BMSC viability and impaired late osteogenic differentiation with high-dose treatment. Therefore, the inhibitory effects of high-dose vancomycin on spinal fusion may result from both reduced BMSC viability and some impairment of osteogenic differentiation.


Sign in / Sign up

Export Citation Format

Share Document