Mouse models of neurodegenerative disease: preclinical imaging and neurovascular component.

Neurodegenerative diseases represent great challenges for basic science and clinical medicine because of their prevalence, pathologies, lack of mechanism-based treatments, and impacts on individuals. Translational research might contribute to the study of neurodegenerative diseases. The mouse has become a key model for studying disease mechanisms that might recapitulate in part some aspects of the corresponding human diseases. Neurode- generative disorders are very complicated and multifacto- rial. This has to be taken in account when testing drugs. Most of the drugs screening in mice are very di cult to be interpretated and often useless. Mouse models could be condiderated a ‘pathway models’, rather than as models for the whole complicated construct that makes a human disease. Non-invasive in vivo imaging in mice has gained increasing interest in preclinical research in the last years thanks to the availability of high-resolution single-photon emission computed tomography (SPECT), positron emission tomography (PET), high eld Magnetic resonance, Optical Imaging scanners and of highly speci c contrast agents. Behavioral test are useful tool to characterize di erent ani- mal models of neurodegenerative pathology. Furthermore, many authors have observed vascular pathological features associated to the di erent neurodegenerative disorders. Aim of this review is to focus on the di erent existing animal models of neurodegenerative disorders, describe behavioral tests and preclinical imaging techniques used for diagnose and describe the vascular pathological features associated to these diseases

Titanium dioxide nanoparticles assembled by DNA molecules hybridization and loading of DNA interacting proteins

This work demonstrates the assembly of TiO2 nanoparticles with attached DNA oligonucleotides into a 3D mesh structure by allowing base pairing between oligonucleotides. A change of the ratio of DNA oligonucleotide molecules and TiO2 nanoparticles regulates the size of the mesh as characterized by UV-visible light spectra, transmission electron microscopy (TEM) and atomic force microscopy (AFM) images. This type of 3D mesh, based on TiO2-DNA oligonucleotide nanoconjugates, can be used for studies of nanoparticle assemblies in materials science, energy science related to dye-sensitized solar cells, environmental science as well as characterization of DNA interacting proteins in the field of molecular biology. As an example of one such assembly, proliferating cell nuclear antigen protein (PCNA) was cloned, its activity was verified, and the protein was purified, loaded onto double strand DNA oligonucleotide-TiO2 nanoconjugates, and imaged by atomic force microscopy. This type of approach may be used to sample and perhaps quantify and/or extract specific cellular proteins from complex cellular protein mixtures based on their affinity for chosen DNA segments assembled into the 3D matrix

Labeling TiO(2) Nanoparticles with Dyes for Optical Fluorescence Microscopy and Determination of TiO(2)-DNA Nanoconjugate Stability

Visualization of nanoparticles without intrinsic optical fluorescence properties is a significant problem when performing intracellular studies. Such is the case with titanium dioxide (TiO(2)) nanoparticles. These nanoparticles, when electronically linked to single-stranded DNA oligonucleotides, have been proposed to be used both as gene knockout devices and as possible tumor imaging agents. By interacting with complementary target sequences in living cells, these photoinducible TiO(2)-DNA nanoconjugates have the potential to cleave intracellular genomic DNA in a sequence specific and inducible manner. The nanoconjugates also become detectable by magnetic resonance imaging with the addition of gadolinium Gd(III) contrast agents. Herein two approaches for labeling TiO(2) nanoparticles and TiO(2)-DNA nanoconjugates with optically fluorescent agents are described. This permits direct quantification of fluorescently labeled TiO(2) nanoparticle uptake in a large population of living cells (>10(4) cells). X-ray fluorescence microscopy (XFM) is combined with fluorescent microscopy to determine the relative intracellular stability of the nanoconjugates and used to quantify intracellular nanoparticles. Imaging the DNA component of the TiO(2)-DNA nanoconjugate by fluorescent confocal microscopy within the same cell shows an overlap with the titanium signal as mapped by XFM. This strongly implies the intracellular integrity of the TiO(2)-DNA nanoconjugates in malignant cells

Gene therapy vectors containing CArG elements from the Egr1 gene are activated by neutron irradiation, cisplatin and doxorubicin

Combining gene therapy with radiotherapy and chemotherapy holds potential to increase the efficacy of cancer treatment, while minimizing side effects. We tested the responsiveness of synthetic gene promoters containing CArG elements from the Early Growth Response 1 (Egr1) gene after neutron irradiation, doxorubicin and cisplatin. Human MCF-7 breast adenocarcinoma and U373-MG glioblastoma cells were transfected with plasmids containing CArG promoters controlling the expression of the green fluorescent protein (GFP). Exposing the cells to neutrons, doxorubicin or cisplatin resulted in a significant induction of transgene expression. Therapeutic advantage was demonstrated by replacing the reporter with the herpes simplex virus thymidine kinase (HSVtk), able to convert the prodrug ganciclovir (GCV) into a cytotoxin. A 1.3 Gy neutron dose caused 49% growth inhibition in MCF-7 cells, which increased to 63% in irradiated CArG-HSVtk-transfectants treated with GCV. Exposure to 0.5 mM cisplatin or 0.01 mM doxorubicin induced a growth inhibition of 25 - 30% in MCF-7 cells. In the presence of GCV, this value increased to 65 - 70% in cells transfected with the CArG promoter constructs driving the expression of HSVtk. These data indicate that combining CArG-mediated HSVtk/ GCV suicide gene therapy with radio- and chemotherapy can enhance antitumor toxicity, and validates future in vivo investigations