5-carboxytetramethylrhodamine-succinimidyl-ester and Disease-Models--Animal

Amyloid β-peptide oligomer (AβO) is widely acknowledged as the promising biomarker for the diagnosis of Alzheimer's disease (AD). In this work, we designed a three-dimensional (3D) DNA walker nanoprobe for AβO detection and real-time imaging in living cells and in vivo. The presence of AβO triggered the DNAzyme walking strand to cleave the fluorophore (TAMRA)-labeled substrate strand modified on the gold nanoparticle (AuNP) surface and release TAMRA-labeled DNA fragment, resulting in the recovery of fluorescent signal. The entire process was autonomous and continuous, without external fuel strands or protease, and finally produced plenty of TAMRA fluorescence, achieving signal amplification effect. The nanoprobe enabled the quantitative detection of AβO in vitro, and the limit of detection was 22.3 pM. Given the good biocompatibility of 3D DNA walker nanoprobe, we extended this enzyme-free signal amplification method to real-time imaging of AβO. Under the microscope, nanoprobe accurately located and visualized the distribution of AβO in living cells. Moreover, in vivo imaging results showed that our nanoprobe could be used to effectively distinguish the AD mice from the wild-type mice. This nanoprobe with the advantages of great sensitivity, high specificity, and convenience, provides an outstanding prospect for AD's early diagnosis development.

Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Brain; Cell Line; Disease Models, Animal; DNA; DNA, Catalytic; Fluorescent Dyes; Gold; Limit of Detection; Metal Nanoparticles; Mice; Mice, Inbred C57BL; Mice, Transgenic; Microscopy, Confocal; Optical Imaging; Rhodamines; Zinc

The serine-aspartic acid-valine (SDV) peptide binds specifically to integrin αvβ3. We developed a Tc-99m and TAMRA labeled peptide, Tc-99m SDV-ECG-K-TAMRA for multimodal imaging of angiogenesis. Tc-99m SDV-ECG-K-TAMRA was prepared in high yield (>96%) and showed low cytotoxicity. Tc-99m tetrofosmin images 1 week after operation, revealed significantly decreased perfusion of the ischemic hindlimb, and the perfusion recovered gradually for 4 weeks. In contrast, Tc-99m SDV-ECG-K-TAMRA uptake was maximal 1 week after the operation (ischemic-to-non-ischemic uptake ratio =5.03±1.01) and decreased gradually. The ischemic-to-non-ischemic ratio of Tc-99m SDV-ECG-K-TAMRA and Tc-99m tetrofosmin was strongly negatively correlated (r =-0.94). A postmortem analysis revealed increased angiogenesis markers and uptake of Tc-99m SDV-ECG-K-TAMRA by ischemic tissue. Our in vivo and in vitro studies revealed substantial uptake of Tc-99m SDV-ECG-K-TAMRA by ischemic tissue. Tc-99m SDV-ECG-K-TAMRA could be a good candidate dual-modality imaging agent to assess angiogenesis.

Topics: Animals; Disease Models, Animal; Fluorescent Dyes; Hindlimb; Ischemia; Mice; Microscopy, Confocal; Multimodal Imaging; Neovascularization, Physiologic; Oligopeptides; Organophosphorus Compounds; Organotechnetium Compounds; Radionuclide Imaging; Radiopharmaceuticals; Rhodamines; Technetium; Tissue Distribution

Mice lacking the membrane tyrosine kinase c-mer have been shown to have altered macro-phage cytokine production and defective phagocytosis of apoptotic cells despite normal phagocytosis of other particles. We show here that c-mer-deficient mice have impaired clearance of infused apoptotic cells and that they develop progressive lupus-like autoimmunity, with antibodies to chromatin, DNA, and IgG. The autoimmunity appears to be driven by endogenous antigens, with little polyclonal B cell activation. These mice should be an excellent model for studying the role of apoptotic debris as an immunogenic stimulus for systemic autoimmunity.

Topics: Animals; Apoptosis; Autoantibodies; Autoimmunity; B-Lymphocytes; c-Mer Tyrosine Kinase; Cardiolipins; Chromatin; Disease Models, Animal; DNA; Female; Fluorescent Dyes; Glomerular Mesangium; Immunoglobulin G; Lupus Erythematosus, Systemic; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; Phagocytosis; Protein-Tyrosine Kinases; Proteinuria; Proto-Oncogene Proteins; Receptor Protein-Tyrosine Kinases; Rheumatoid Factor; Rhodamines