carbocyanines and Neurodegenerative-Diseases

Matrix metalloproteinases (MMPs), particularly gelatinases (MMP-2/-9), are involved in neurovascular impairment after stroke. Detection of gelatinase activity in vivo can provide insight into blood-brain barrier disruption, hemorrhage, and nerve cell injury or death. We applied gelatinase-activatable cell-penetrating peptides (ACPP) with a cleavable l-amino acid linker to examine gelatinase activity in primary neurons in culture and ischemic mouse brain in vivo We found uptake of Cy5-conjugated ACPP (ACPP-Cy5) due to gelatinase activation both in cultured neurons exposed to n-methyl-d-aspartate and in mice after cerebral ischemia. Fluorescence intensity was significantly reduced when cells or mice were treated with MMP inhibitors or when a cleavage-resistant ACPP-Cy5 was substituted. We also applied an ACPP dendrimer (ACPPD) conjugated with multiple Cy5 and/or gadolinium moieties for fluorescence and magnetic resonance imaging (MRI) in intact animals. Fluorescence analysis showed that ACPPD was detected in sub-femtomole range in ischemic tissues. Moreover, MRI and inductively coupled plasma mass spectrometry revealed that ACPPD produced quantitative measures of gelatinase activity in the ischemic region. The resulting spatial pattern of gelatinase activity and neurodegeneration were very similar. We conclude that ACPPs are capable of tracing spatiotemporal gelatinase activity in vivo, and will therefore be useful in elucidating mechanisms of gelatinase-mediated neurodegeneration after stroke.

Topics: Animals; Brain Ischemia; Carbocyanines; Cell-Penetrating Peptides; Cells, Cultured; Gelatinases; Magnetic Resonance Imaging; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Mice; Molecular Probes; Neurodegenerative Diseases; Stroke

Neurotrophic factors may be future therapeutic agents for neurodegenerative disease. In the screening of biologically active molecules for neurotrophic potency, we found that a photosensitizing cyanine dye, NK-4, had remarkable neurotrophic activities and was a potent radical scavenger.. In this study, we evaluated the effect of NK-4 on the protection of neurons against oxidative damage and investigated the associated intracellular signaling pathways. Subsequently, we evaluated the effect of NK-4 in an animal model of neurodegeneration. In vitro, NK-4 showed dose-dependent protection of PC12 cells from toxicity induced by oxidative stress caused by hydrogen peroxide (H(2)O(2)) or 6-hydroxydopamine (6-OHDA). Comparison of extracellular signal-regulated kinase signaling pathways between treatment with NK-4 and nerve growth factor (NGF) using K252a, an inhibitor of the NGF receptor TrkA, revealed that NK-4 activity occurs independently of NGF receptors. LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, blocked the protective effect of NK-4, and NK-4 caused activation of Akt/protein kinase B, a downstream effector of PI3K. These results suggest that the neuroprotective effects of NK-4 are mediated by the PI3K-Akt signaling pathway. NK-4 treatment also attenuated stress-induced activation of SAPK/JNK, which suggests that NK-4 activates a survival signaling pathway and inhibits stress-activated apoptotic pathways independently of the TrkA receptor in neuronal cells. In vivo, administration of NK-4 improved motor coordination in genetic ataxic hamsters, as assessed by rota-rod testing. Histological analysis showed that cerebellar atrophy was significantly attenuated by NK-4 treatment. Notably, the Purkinje cell count in the treated group was threefold higher than that in the vehicle group.. These results suggest that NK-4 is a potential agent for therapy for neurodegenerative disorders based on the activation of survival signaling pathways.

Topics: Animals; Atrophy; Carbocyanines; Cell Proliferation; Cerebellar Ataxia; Coloring Agents; Cricetinae; Disease Models, Animal; Female; Intracellular Space; JNK Mitogen-Activated Protein Kinases; Male; Mutation; Neurites; Neurodegenerative Diseases; Neuroprotective Agents; Neurotoxins; Oxidative Stress; p38 Mitogen-Activated Protein Kinases; PC12 Cells; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; Psychomotor Performance; Purkinje Cells; Rats; Signal Transduction

In addition to its key role in complex motor function, the cerebellum is increasingly recognized to have a role in cognition. Thus, motor and cognitive deficits can be associated with cerebellar degeneration. After unilateral lesion in cerebellum (folia VI) was caused by Quinolinic acid, CM-DiI labeled mesenchymal stem cells (MSCs), which were isolated and purified from bone marrow, were transplanted into the damaged folium. Motor function was assessed using the cylinder test, rotarod, hanging wire and beam balance during 6 weeks after transplantation. Cognitive function was assessed using the Morris water maze learning paradigm in 3 weeks after transplantation. Six weeks after transplantation surviving MSCs were detectable in QA-treated animals. The MSC-transplanted group showed markedly improved functional performance in spatial memory, motor learning, locomotor asymmetry, dysmetria, abnormality in neuromuscular strength and equilibrium 2-6 weeks compared with the controls. We found that cerebellar lesions produced deficits (folia VI) in motor and cognitive aspects of a spatial task. The results indicate that transplantation of MSCs can significantly reduce the behavioral abnormalities of these animals during six weeks after engraftment. According to results of this assay, cell therapy by means of bone marrow derived adult stem cells promises for treatment of cerebellar diseases.

Topics: Analysis of Variance; Animals; Behavior, Animal; Carbocyanines; Cerebellum; Disease Models, Animal; Female; Hand Strength; Maze Learning; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Movement; Neurodegenerative Diseases; Organ Size; Psychomotor Performance; Rats; Rats, Wistar; Time Factors