The major motor symptoms of Parkinson’s disease do not occur until a majority of the dopaminergic neurons in the midbrain SNpc have already died. For this reason, it is critical to identify biomarkers that will allow for the identification of presymptomatic individuals. In this study, we examine the baseline expression of the antioxidant protein Glutathione S-transferase pi (GSTpi) in blood of PD and environmental and age-matched controls and compare it to GSTpi levels following exposure to 1-methyl-4-phenylpyridinium (MPP+), an agent that has been shown to induce oxidative stress. We find that 4 hours of exposure to MPP+, significant increases in GSTpi levels can be observed in the leukocytes of PD patients. No changes were seen in other blood components. This suggests that GSTpi and potentially other members of this and other anti-oxidant families may be viable biomarkers for PD.

The A/VN/1203/04 H5N1 influenza virus is capable of infecting the CNS of mice and inducing a number of neurodegenerative pathologies. Here, we examined the effects of H5N1 on several pathological aspects affected in parkinsonism, including loss of the phenotype of dopaminergic (DAergic) neurons located in the substantia nigra pars compacta (SNpc), expression of mono- and indolamines in brain, alterations in SNpc microglia number and morphology, and expression of cytokines, chemokines and growth factors. We find that H5N1 induces a transient loss of the DAergic phenotype in SNpc and now report that this loss recovers by 90 days post infection (dpi). A similar pattern of loss and recovery was seen in monoamine levels of the basal ganglia. The inflammatory response in lung and different regions of the brain known to be targets of the H5N1 virus (brainstem, substantia nigra, striatum, and cortex) were examined at 3, 10, 21, 60 and 90 dpi. We found a significant increase in the number of activated microglia in each of these brain regions that lasted at least 90 days. We also quantified expression of IL-1α, IL-1β, IL-2, IL-6, IL-9, IL-10, IL-12(p70), IL-13, TNF-α, IFN-γ, GM-CSF, G-CSF, M-CSF, eotaxin, IP-10, KC, MCP-1, MIP-1α, MIP-1β and VEGF and find that the pattern and levels of expression are dependent on both brain region and time after infection. We conclude that H5N1 infection in mice induces a long-lasting inflammatory response in brain and may play a contributing factor in the development of pathologies in neurodegenerative disorders.

The dentate gyrus is a major site of plasticity in the adult brain, giving rise to thousands of new neurons every day, through the process of adult neurogenesis. Although the majority of these cells die within two weeks of their birth, they can be rescued from death by various forms of learning. Successful acquisition of select types of associative and spatial memories increases the number of these cells that survive. Here, we investigated the possibility that an entirely different form of learning, physical skill learning, could rescue new hippocampal cells from death. To test this possibility, rats were trained with a physically-demanding and technically-difficult version of a rotarod procedure. Acquisition of the physical skill greatly increased the number of new hippocampal cells that survived. The number of surviving cells positively correlated with performance on the task. Only animals that successfully mastered the task retained the cells that would have otherwise died. Animals that failed to learn, and those that did not learn well did not retain any more cells than those that were untrained. Importantly, acute voluntary exercise in activity wheels did not increase the number of surviving cells. These data suggest that acquisition of a physical skill can increase the number of surviving hippocampal cells. Moreover, learning an easier version of the task did not increase cell survival. These results are consistent with previous reports revealing that learning only rescues new neurons from death when acquisition is sufficiently difficult to achieve. Finally, complete hippocampal lesions did not disrupt acquisition of this physical skill. Therefore, physical skill training that does not depend on the hippocampus can effectively increase the number of surviving cells in the adult hippocampus, the vast majority of which become mature neurons.

Infection by Shiga toxin-producing Escherichia coli causes hemorrhagic colitis, hemolytic uremic syndrome (HUS), acute renal failure, and also central nervous system complications in around 30% of the children affected. Besides, neurological deficits are one of the most unrepairable and untreatable outcomes of HUS. Study of the striatum is relevant because basal ganglia are one of the brain areas most commonly affected in patients that have suffered from HUS and since the deleterious effects of a sub-lethal dose of Shiga toxin have never been studied in the striatum, the purpose of this study was to attempt to simulate an infection by Shiga toxin-producing E. coli in a murine model. To this end, intravenous administration of a sub-lethal dose of Shiga toxin 2 (0.5 ηg per mouse) was used and the correlation between neurological manifestations and ultrastructural changes in striatal brain cells was studied in detail. Neurological manifestations included significant motor behavior abnormalities in spontaneous motor activity, gait, pelvic elevation and hind limb activity eight days after administration of the toxin. Transmission electron microscopy revealed that the toxin caused early perivascular edema two days after administration, as well as significant damage in astrocytes four days after administration and significant damage in neurons and oligodendrocytes eight days after administration. Interrupted synapses and mast cell extravasation were also found eight days after administration of the toxin. We thus conclude that the chronological order of events observed in the striatum could explain the neurological disorders found eight days after administration of the toxin.

We describe a novel spontaneous mouse mutant, laggard (lag), characterized by a flat head, motor impairment and growth retardation. The mutation is inherited as an autosomal recessive trait, and lag/lag mice suffer from cerebellar ataxia and die before weaning. lag/lag mice exhibit a dramatic reduction in brain size and slender optic nerves. By positional cloning, we identify a splice site mutation in Kif14. Transgenic complementation with wild-type Kif14-cDNA alleviates ataxic phenotype in lag/lag mice. To further confirm that the causative gene is Kif14, we generate Kif14 knockout mice and find that all of the phenotypes of Kif14 knockout mice are similar to those of lag/lag mice. The main morphological abnormality of lag/lag mouse is severe hypomyelination in central nervous system. The lag/lag mice express an array of myelin-related genes at significantly reduced levels. The disrupted cytoarchitecture of the cerebellar and cerebral cortices appears to result from apoptotic cell death. Thus, we conclude that Kif14 is essential for the generation and maturation of late-developing structures such as the myelin sheath, cerebellar and cerebral cortices. So far, no Kif14-deficient mice or mutation in Kif14 has ever been reported and we firstly define the biological function of Kif14 in vivo. The discovery of mammalian models, laggard, has opened up horizons for researchers to add more knowledge regarding the etiology and pathology of brain malformation.

Neurotrophic factors, such as glial cell line-derived neurotrophic factor (GDNF), are promising therapeutic agents for neurodegenerative diseases. However, the application of GDNF to treat these diseases effectively is limited because the blood–brain barrier (BBB) prevents the local delivery of macromolecular therapeutic agents from entering the central nervous system (CNS). Focused ultrasound combined with microbubbles (MBs) using appropriate parameters has been previously demonstrated to be able to open the BBB locally and noninvasively. This study investigated the targeted delivery of GDNF MBs through the BBB by magnetic resonance imaging (MRI)-guided focused ultrasound. Evans Blue extravasation and histological examination were used to determine the optimum focused ultrasound parameters. Enzyme-linked immunosorbent assay was performed to verify the effects of GDNF bound on MBs using a biotin–avidin bridging chemistry method to promote GDNF delivery into the brain. The results showed that GDNF can be delivered locally and noninvasively into the CNS through the BBB using MRI-guided focused ultrasound combined with MBs under optimum parameters. MBs that bind GDNF combined with MRI-guided focused ultrasound may be an effective way of delivering neurotrophic factors directly into the CNS. The method described herein provides a potential means of treating patients with CNS diseases.

Radiation therapy has proven efficacy for treating brain tumors and metastases. Higher doses and larger treatment fields increase the probability of eliminating neoplasms and preventing reoccurrence, but dose and field are limited by damage to normal tissues. Normal tissue injury is greatest during development and in populations of proliferating cells but also occurs in adults and older individuals and in non-proliferative cell populations. To better understand radiation-induced normal tissue injury and how it may be affected by aging, we exposed young adult, middle-aged, and old rats to 10 Gy of whole brain irradiation and assessed in gray- and white matter the responses of microglia, the primary cellular mediators of radiation-induced neuroinflammation, and oligodendrocyte precursor cells, the largest population of proliferating cells in the adult brain. We found that aging and/or irradiation caused only a few microglia to transition to the classically “activated” phenotype, e.g., enlarged cell body, few processes, and markers of phagocytosis, that is seen following more damaging neural insults. Microglial changes in response to aging and irradiation were relatively modest and three markers of reactivity - morphology, proliferation, and expression of the lysosomal marker CD68- were regulated largely independently within individual cells. Proliferation of oligodendrocyte precursors did not appear to be altered during normal aging but increased following irradiation. The impacts of irradiation and aging on both microglia and oligodendrocyte precursors were heterogeneous between white- and gray matter and among regions of gray matter, indicating that there are regional regulators of the neural response to brain irradiation. By several measures, the CA3 region of the hippocampus appeared to be differentially sensitive to effects of aging and irradiation. The changes assessed here likely contribute to injury following inflammatory challenges like brain irradiation and represent important end-points for analysis in studies of therapeutic strategies to protect patients from neural dysfunction.

Skeletal muscle atrophy is a consequence of muscle inactivity resulting from denervation, unloading and immobility. It accompanies many chronic disease states and also occurs as a pathophysiologic consequence of normal aging. In all these conditions, ubiquitin-dependent proteolysis is a key regulator of the loss of muscle mass, and ubiquitin ligases confer specificity to this process by interacting with, and linking ubiquitin moieties to target substrates through protein∶protein interaction domains. Our previous work suggested that the ubiquitin-protein ligase Nedd4-1 is a potential mediator of skeletal muscle atrophy associated with inactivity (denervation, unloading and immobility). Here we generated a novel tool, the Nedd4-1 skeletal muscle-specific knockout mouse (myoCre;Nedd4-1flox/flox) and subjected it to a well validated model of denervation induced skeletal muscle atrophy. The absence of Nedd4-1 resulted in increased weights and cross-sectional area of type II fast twitch fibres of denervated gastrocnemius muscle compared with wild type littermates controls, at seven and fourteen days following tibial nerve transection. These effects are not mediated by the Nedd4-1 substrates MTMR4, FGFR1 and Notch-1. These results demonstrate that Nedd4-1 plays an important role in mediating denervation-induced skeletal muscle atrophy in vivo.

Background

Positron Emission Tomography (PET) measurement was applied to the brain of the common marmoset, a small primate species, treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). The marmoset shows prominent Parkinson’s disease (PD) signs due to dopaminergic neural degeneration. Recently, the transgenic marmoset (TG) carrying human PD genes is developing. For phenotypic evaluations of TG, non-invasive PET measurement is considered to be substantially significant. As a reference control for TG, the brain of the MPTP-marmoset as an established and valid model was scanned by PET. Behavioral analysis was also performed by recording locomotion of the MPTP-marmoset, as an objective measure of PD signs.

Methodology/Principal Findings

Marmosets received several MPTP regimens (single MPTP regimen: 2 mg/kg, s.c., per day for 3 consecutive days) were used for PET measurement and behavioral observation. To measure immobility as a central PD sign, locomotion of marmosets in their individual living cages were recorded daily by infrared sensors. Daily locomotion counts decreased drastically after MPTP regimens and remained diminished for several months or more. PET scan of the brain, using [11C]PE2I as a ligand of the dopamine (DA) transporter, was performed once several months after the last MPTP regimen. The mean binding potential (BPND) in the striatum (putamen and caudate) of the MPTP-marmoset group was significantly lower than that of the MPTP-free control group (n = 5 for each group). In the MPTP-marmosets, the decrease of BPND in the striatum closely correlated with the decrease in locomotion counts (r = 0.98 in putamen and 0.91 in caudate).

Conclusion/Significance

The present characterization of neural degeneration using non-invasive PET imaging and of behavioral manifestation in the MPTP marmoset mimics typical PD characteristics and can be useful in evaluating the phenotype of TG marmosets being developed.

We sought to determine if tendon inflammatory and histopathological responses increase in aged rats compared to young rats performing a voluntary upper extremity repetitive task, and if these changes are associated with motor declines. Ninety-six female Sprague-Dawley rats were used in the rat model of upper extremity overuse: 67 aged and 29 young adult rats. After a training period of 4 weeks, task rats performed a voluntary high repetition low force (HRLF) handle-pulling task for 2 hrs/day, 3 days/wk for up to 12 weeks. Upper extremity motor function was assessed, as were inflammatory and histomorphological changes in flexor digitorum and supraspinatus tendons. The percentage of successful reaches improved in young adult HRLF rats, but not in aged HRLF rats. Forelimb agility decreased transiently in young adult HRLF rats, but persistently in aged HRLF rats. HRLF task performance for 12 weeks lead to increased IL-1beta and IL-6 in flexor digitorum tendons of aged HRLF rats, compared to aged normal control (NC) as well as young adult HRLF rats. In contrast, TNF-alpha increased more in flexor digitorum tendons of young adult 12-week HRLF rats than in aged HRLF rats. Vascularity and collagen fibril organization were not affected by task performance in flexor digitorum tendons of either age group, although cellularity increased in both. By week 12 of HRLF task performance, vascularity and cellularity increased in the supraspinatus tendons of only aged rats. The increased cellularity was due to increased macrophages and connective tissue growth factor (CTGF)-immunoreactive fibroblasts in the peritendon. In conclusion, aged rat tendons were overall more affected by the HRLF task than young adult tendons, particularly supraspinatus tendons. Greater inflammatory changes in aged HRLF rat tendons were observed, increases associated temporally with decreased forelimb agility and lack of improvement in task success.

Background

Traumatic brain injury (TBI) induces a complex sequence of apopototic cascades that contribute to secondary tissue damage. The aim of this study was to investigate the effects of salidroside, a phenolic glycoside with potent anti-apoptotic properties, on behavioral and histological outcomes, brain edema, and apoptosis following experimental TBI and the possible involvement of the phosphoinositide 3-kinase/protein kinase B (PI3K)/Akt signaling pathway.

Methodology/Principal Findings

Mice subjected to controlled cortical impact injury received intraperitoneal salidroside (20, or 50 mg/kg) or vehicle injection 10 min after injury. Behavioral studies, histology analysis and brain water content assessment were performed. Levels of PI3K/Akt signaling-related molecules, apoptosis-related proteins, cytochrome C (CytoC), and Smac/DIABLO were also analyzed. LY294002, a PI3K inhibitor, was administered to examine the mechanism of protection. The protective effect of salidroside was also investigated in primary cultured neurons subjected to stretch injury. Treatment with 20 mg/kg salidroside_significantly improved functional recovery and reduced brain tissue damage up to post-injury day 28. Salidroside_also significantly reduced neuronal death, apoptosis, and brain edema at day 1. These changes were associated with significant decreases in cleaved caspase-3, CytoC, and Smac/DIABLO at days 1 and 3. Salidroside increased phosphorylation of Akt on Ser473 and the mitochondrial Bcl-2/Bax ratio at day 1, and enhanced phosphorylation of Akt on Thr308 at day 3. This beneficial effect was abolished by pre-injection of LY294002. Moreover, delayed administration of salidroside at 3 or 6 h post-injury reduced neuronal damage at day 1. Salidroside treatment also decreased neuronal vulnerability to stretch-induced injury in vitro.

Conclusions/Significance

Post-injury salidroside improved long-term behavioral and histological outcomes and reduced brain edema and apoptosis following TBI, at least partially via the PI3K/Akt signaling pathway.

Voltage-gated Ca2+ (Cav) channels control neuronal functions including neurotransmitter release and gene expression. The Cacna1a gene encodes the α1 subunit of the pore-forming Cav2.1 channel. Mice with mutations in this gene form useful tools for defining channel functions. The recessive ataxic tottering-6j strain that was generated in the Neuroscience Mutagenesis Facility at The Jackson Laboratory has a mutation in the Cacna1a gene. However, the effect of this mutation has not been investigated in detail. In this study, mutation analysis shows a base substitution (C-to-A) in the consensus splice acceptor sequence linked to exon 5, which results in the skipping of exon 5 and the splicing of exon 4 directly to exon 6. The effect of this mutation is expected to be severe as the expressed α1 subunit protein lacks a significant part of the S4–S5 linker, S5, and part of S5–S6 linker in domain I. Tottering-6j mice display motor dysfunctions in the footprint, rotating rod, and hind-limb extension tests. Although cytoarchitecture of the mutant brains appears normal, tyrosine hydroxylase was persistently expressed in cerebellar Purkinje cells in the adult mutant mice. These results indicate that tottering-6j is a useful model for functional studies of the Cav2.1 channel.