In vitro response to functionalized self-assembled peptide scaffolds for three-dimensional cell culture

Nanomaterials are rich in potential, particularly for the formation of scaffolds that mimic the landscape of the host environment of the cell. This niche arises from the spatial organization of a series of biochemical and biomechanical signals. Self-assembling peptides have emerged as an important tool in the development of functional (bio-)nanomaterials; these simple, easily synthesized subunits form structures which present the properties of these larger, more complex systems. Scaffolds based upon these nanofibrous matrices are promising materials for regenerative medicine as part of a new methodology in scaffold design where a "bottom-up" approach is used in order to simulate the native cellular milieu. Importantly, SAPs hold the potential to be bioactive through the presentation of biochemical and biomechanical signals in a context similar to the natural extracellular matrix, making them ideal targets for providing structural and chemical support in a cellular context. Here, we discuss a new methodology for the presentation of biologically relevant epitopes through their effective presentation on the surface of the nanofibers. Here, we demonstrate that these signals have a direct effect on the viability of cells within a three-dimensional matrix as compared with an unfunctionalized, yet mechanically and morphologically similar system. © 2014 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 197-205, 2014.

Membrane-bound alkaline phosphatase from ectopic mineralization and rat bone marrow cell culture

Cells from rat bone marrow exhibit the proliferation-differentiation sequence of osteoblasts, form mineralized extracellular matrix in vitro and release alkaline phosphatase into the medium. Membrane-bound alkaline phosphatase was obtained by method that is easy to reproduce, simpler and fast when compared with the method used to obtain the enzyme from rat osseous plate. The membrane-bound alkaline phosphatase from cultures of rat bone marrow cells has a MWr of about 120 kDa and specific PNPP activity of 1200 U/tng. The ecto-enzyme is anchored to the plasma membrane by the GPI anchor and can be released by PIPLC (selective treatment) or polidocanol (0.2 mg/mL protein and 1% (w/v) detergent). The apparent optimum pH for PNPP hydrolysis by the enzyme was pH 10. This fraction hydrolyzes ATP (240 U/mg), ADP (350 U/ mg), glucose 1-phosphate (1100 U/mg), glucose 6-phosphate (340 Wing), fructose 6-phosphate (460 U/mg), pyrophosphate (330 U/mg) and (3glycerophosphate (600 U/mg). Cooperative effects were observed for the hydrolysis of PPi and beta-glycerophosphate. PNPPase activity was inhibited by 0.1 mM vanadate (46%), 0.1 mM ZnCl2 (68%), 1 mM levamisole (66%), 1 mM arsenate (44%), 10 mM phosphate (21%) and 1 mM theophylline (72%). We report the biochemical characterization of membrane-bound alkaline phosphatase obtained from rat bone marrow cells cultures, using a method that is simple, rapid and easy to reproduce. Its properties are compared with those of rat osseous plate enzyme and revealed that the alkaline phosphatase obtained has some kinetics and structural behaviors with higher levels of enzymatic activity, facilitating the comprehension of the mineralization process and its function. (c) 2006 Elsevier B.V. All rights reserved.

Human breast tumor slices as an alternative approach to cell lines to individualize research for each patient

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Borderline leprosy: in situ and cytokine profile in supernatant of mononuclear of cell culture

In order to contribute to a better understanding of cytokine participation in borderline leprosy, in the present study we determined - by in vitro and in situ examinations - the production of these cytokine mediation in non-treated borderline tuberculoid (BT) patients and borderline lepromatous (BL) patients. Seven non-treated BT patients, 12 non-treated BL patients, besides 19 healthy individuals (control group), were evaluated. Peripheral blood mononuclear cells (PBMC) were stimulated or not with specific-M. leprae stimulus (whole and sonicated M. leprae antigens) and a non-specific stimulus. After 48 hours, supernatant was collected for TNF-alpha, IFN-gamma, IL-10 and TGF-beta1 cytokine determination by ELISA. Biopsies from cutaneous lesions were submitted to histological analysis and hematoxylin-eosin and Fite-Faraco stainings; the sections then underwent iNOS, IL-10 and TGF-beta1 in situ detection by immunohistochemistry. Cytokine quantification in PBMC supernatants from patients showed that BT patients produced higher levels of IFN-gamma. Compared to healthy individuals, both borderline patient groups produced lower levels of TGF-beta1 while BL patients generated lower IL-10 levels. The in situ iNOS expression was higher in BT patients compared to BL individuals. on the order hand, TGF-beta1 cytokine revealed a higher proportion of immunostained cells in BL patients. There was no significant difference in IL-10 level between BT and BL patients. Regarding cutaneous lesions, in BL patients there was a negative correlation between TGF-beta1 tissue expression and IL-10. Independently of the clinical form, we observed a positive correlation between TGF-beta1 and bacterial index as well as a negative correlation between the TGF-beta1 tissue expression and iNOS. The results even showed a positive correlation between iNOS tissue expression and production of IFN-gamma by PBMC stimulated with M. leprae antigens. Taken together, the histopathological and immunological observations reinforce the notion of immunological instability in borderline leprosy patients and indicating the participation of mixed cytokines profiles in these individuals, specifically a Th1 profile in BT patients and Th2 profile in BL patients, with a possible participation of T-regulatory lymphocytes.

Evaluation of castor oil-based polyurethane membranes in rat bone-marrow cell culture

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Mineral Trioxide Aggregate-based Endodontic Sealer Stimulates Hydroxyapatite Nucleation in Human Osteoblast-like Cell Culture

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Photodynamic therapy associating Photogem (R) and blue LED on L929 and MDPC-23 cell culture

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Callus cell culture of Pothomorphe umbellata (L.) under stress condition leads to high content of peroxidase enzyme

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of salt stress on polyamine metabolism in bean cell culture

The adaptive capacity of bean (Phaseolus vulgaris L.) calluses (cultivars IAC-carioca, JALO EEP-558, BAT-93 and IAPAR-14) to salt stress (0-80 mM) was verified to determine the existence of biochemical markers such as organic and inorganic compounds, and metabolism of polyamines. The results obtained demonstrate that salt (NaCl) interfered with all the parameters analyzed and its intensity ranged due to the salt concentration and the cultivars used.

Evaluation of cell culture cytotoxicity of five root canal sealers

The cytotoxicity of four calcium hydroxide-based root canal sealers (Sealapex, CRCS, Apexit, and Sealer 26) and one zinc oxide-eugenol-based sealer (Fill Canal) was evaluated microscopically for morphological changes in rat peritoneal macrophages. The least cytotoxic sealer was Fill Canal, followed in increasing order of cytotoxicity by CRCS, Sealer 26, Apexit, and Sealapex. Copyright © 2000 by The American Association of Endodontists.

Simple method for culture of peripheral blood lymphocytes of Testudinidae.

We developed and optimized a simple, efficient and inexpensive method for in vitro culture of peripheral blood lymphocytes from the Brazilian tortoise Chelonoidis carbonaria (Testudinidae), testing various parameters, including culture medium, mitogen concentration, mitotic index, culture volume, incubation time, and mitotic arrest. Peripheral blood samples were obtained from the costal vein of four couples. The conditions that gave a good mitotic index were lymphocytes cultured at 37°C in minimum essential medium (7.5 mL), with phytohemagglutinin as a mitogen (0.375 mL), plus streptomycin/penicillin (0.1 mL), and an incubation period of 72 h. Mitotic arrest was induced by 2-h exposure to colchicine (0.1 mL), 70 h after establishing the culture. After mitotic arrest, the cells were hypotonized with 0.075 M KCl for 2 h and fixed with methanol/acetic acid (3:1). The non-banded mitotic chromosomes were visualized by Giemsa staining. The diploid chromosome number of C. carbonaria was found to be 52 in females and males, and sex chromosomes were not observed. We were able to culture peripheral blood lymphocytes of a Brazilian tortoise in vitro, for the preparation of mitotic chromosomes.

Platelet lysate 3D scaffold supports mesenchymal stem cell chondrogenesis: An improved approach in cartilage tissue engineering

Articular lesions are still a major challenge in orthopedics because of cartilage's poor healing properties. A major improvement in therapeutics was the development of autologous chondrocytes implantation (ACI), a biotechnology-derived technique that delivers healthy autologous chondrocytes after in vitro expansion. To obtain cartilage-like tissue, 3D scaffolds are essential to maintain chondrocyte differentiated status. Currently, bioactive 3D scaffolds are promising as they can deliver growth factors, cytokines, and hormones to the cells, giving them a boost to attach, proliferate, induce protein synthesis, and differentiate. Using mesenchymal stem cells (MSCs) differentiated into chondrocytes, one can avoid cartilage harvesting. Thus, we investigated the potential use of a platelet-lysate-based 3D bioactive scaffold to support chondrogenic differentiation and maintenance of MSCs. The MSCs from adult rabbit bone marrow (n=5) were cultivated and characterized using three antibodies by flow cytometry. MSCs (1×105) were than encapsulated inside 60μl of a rabbit platelet-lysate clot scaffold and maintained in Dulbecco's Modified Eagle Medium Nutrient Mixture F-12 supplemented with chondrogenic inductors. After 21 days, the MSCs-seeded scaffolds were processed for histological analysis and stained with toluidine blue. This scaffold was able to maintain round-shaped cells, typical chondrocyte metachromatic extracellular matrix deposition, and isogenous group formation. Cells accumulated inside lacunae and cytoplasm lipid droplets were other observed typical chondrocyte features. In conclusion, the usage of a platelet-lysate bioactive scaffold, associated with a suitable chondrogenic culture medium, supports MSCs chondrogenesis. As such, it offers an alternative tool for cartilage engineering research and ACI. © 2013 Informa UK Ltd.

Methylmercury intoxication activates nitric oxide synthase in chick retinal cell culture

The visual system is a potential target for methylmercury (MeHg) intoxication. Nevertheless, there are few studies about the cellular mechanisms of toxicity induced by MeHg in retinal cells. Various reports have indicated a critical role for nitric oxide synthase (NOS) activation in modulating MeHg neurotoxicity in cerebellar and cortical regions. The aim of the present study is to describe the effects of MeHg on cell viability and NOS activation in chick retinal cell cultures. For this purpose, primary cultures were prepared from 7-day-old chick embryos: retinas were aseptically dissected and dissociated and cells were grown at 37ºC for 7-8 days. Cultures were exposed to MeHg (10 µM, 100 µM, and 1 mM) for 2, 4, and 6 h. Cell viability was measured by MTT method and NOS activity by monitoring the conversion of L-[H3]-arginine to L-[H3]-citrulline. The incubation of cultured retina cells with 10 and 100 µM MeHg promoted an increase of NOS activity compared to control (P < 0.05). Maximum values (P < 0.05) were reached after 4 h of MeHg incubation: increases of 81.6 ± 5.3 and 91.3 ± 3.7%, respectively (data are reported as mean ± SEM for 4 replicates). MeHg also promoted a concentration- and time-dependent decrease in cell viability, with the highest toxicity (a reduction of about 80% in cell viability) being observed at the concentration of 1 mM and after 4-6 h of incubation. The present study demonstrates for the first time the modulation of MeHg neurotoxicity in retinal cells by the nitrergic system