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Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease, characterised by the degeneration of motor neurons innervating skeletal muscle. The mechanisms underlying neurodegeneration in ALS are not yet fully elucidated, and with current therapeutics only able to extend lifespan by a matter of months there is a clear need for novel therapies to increase lifespan and patient quality of life. Here, we evaluated whether moderate-intensity treadmill exercise and/or treatment with metallothionein-2 (MT2), a neuroprotective protein, could improve survival, behavioural or neuropathological outcomes in SOD1G93A familial ALS mice. Six-week-old female SOD1G93A mice were allocated to one of four treatment groups: MT2 injection, i.m.; moderate treadmill exercise; neither MT2 nor exercise; or both MT2 and exercise. MT2-treated mice survived around 3% longer than vehicle-treated mice, with this mild effect reaching statistical significance in Cox proportional hazards analysis once adjusted for potential confounders. Mixed model body weight trajectories over time indicated that MT2-treated mice, with or without exercise, reached maximum body weight at a later age, suggesting a delay in disease onset of around 4% compared to saline-treated mice. Exercise alone did not significantly increase survival or delay disease onset, and neither exercise nor MT2 substantially ameliorated gait abnormalities or muscle strength loss. We conclude that neither exercise nor MT2 treatment was detrimental in female SOD1G93A mice, and further study could determine whether the mild effect of peripheral MT2 administration on disease onset and survival could be improved via direct administration of MT2 to the central nervous system.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease, characterised by the degeneration of motor neurons innervating skeletal muscle. The mechanisms underlying neurodegeneration in ALS are not yet fully elucidated, and with current therapeutics only able to extend lifespan by a matter of months there is a clear need for novel therapies to increase lifespan and patient quality of life. Here, we evaluated whether moderate-intensity treadmill exercise and/or treatment with metallothionein-2 (MT2), a neuroprotective protein, could improve survival, behavioural or neuropathological outcomes in SOD1

The low-density lipoprotein receptor-related protein receptors 1 and 2 (LRP1 and LRP2) are emerging as important cell signaling mediators in modulating neuronal growth and repair. We examined whether LRP1 and LRP2 are able to mediate a specific aspect of neuronal growth: axon guidance. We sought to identify LRP1 and LRP2 ligands that could induce axonal chemoattraction, which might have therapeutic potential. Using embryonic sensory neurons (rat dorsal root ganglia) in a growth cone turning assay, we tested a range of LRP1 and LRP2 ligands for the ability to guide growth cone navigation. Three ligands were chemorepulsive: α-2-macroglobulin, tissue plasminogen activator, and metallothionein III. Conversely, only one LRP ligand, metallothionein II, was found to be chemoattractive. Chemoattraction toward a gradient of metallothionein II was calcium-dependent, required the expression of both LRP1 and LRP2, and likely involves further co-receptors such as the tropomyosin-related kinase A (TrkA) receptor. The potential for LRP-mediated chemoattraction to mediate axonal regeneration was examined in vivo in a model of chemical denervation in adult rats. In these in vivo studies, metallothionein II was shown to enhance epidermal nerve fiber regeneration so that it was complete within 7 days compared with 14 days in saline-treated animals. Our data demonstrate that both LRP1 and LRP2 are necessary for metallothionein II-mediated chemotactic signal transduction and that they may form part of a signaling complex. Furthermore, the data suggest that LRP-mediated chemoattraction represents a novel, non-classical signaling system that has therapeutic potential as a disease-modifying agent for the injured peripheral nervous system.

Multiple system atrophy (MSA) exhibits widespread astrogliosis together with α-synuclein (α-syn) glial cytoplasmic inclusions (GCIs) in mature oligodendrocytes. We quantified astrocyte activation by morphometric analysis of MSA cases, and investigated the correlation to GCI proximity. Using Imaris software, we obtained "skinned" three-dimensional models of GFAP-positive astrocytes in MSA and control tissue (n=75) from confocal z-stacks and measured the astrocyte process length and thickness and radial distance to the GCI. Astrocytes proximal to GCI-containing oligodendrocytes (r25μm) had significantly (p, 0.05) longer and thicker processes characteristic of activation than distal astrocytes (r25μm), with a reciprocal linear correlation (m, 90μm(2)) between mean process length and radial distance to the nearest GCI (R(2), 0.7). In primary cell culture studies, α-syn addition caused ERK-dependent activation of rat astrocytes and perinuclear α-syn inclusions in mature (MOSP-positive) rat oligodendrocytes. Activated astrocytes were also observed in close proximity to α-syn deposits in a unilateral rotenone-lesion mouse model. Moreover, unilateral injection of MSA tissue-derived α-syn into the mouse medial forebrain bundle resulted in widespread neuroinflammation in the α-syn-injected, but not sham-injected hemisphere. Taken together, our data suggests that the action of localized concentrations of α-syn may underlie both astrocyte and oligodendrocyte MSA pathological features.

Type 2 diabetes is a chronic metabolic disorder that is becoming a leading cause of morbidity and mortality. The prolonged time-course of human type 2 diabetes makes modelling of the disease difficult and additional animal models and methodologies are needed. The goal of this study was to develop and characterise a new method that allows controlled, targeted and sustained induction of discrete stages of type 2 diabetes in rodents. Using adult, male rats, we employed a three-week high fat-diet regimen and confirmed development of obesity-associated glucose intolerance, a key feature of human type 2 diabetes. Next, we utilised osmotic mini-pumps to infuse streptozotocin (STZ; doses ranging 80–200 mg/kg) over the course of 14-days to decrease insulin-producing capacity thus promoting hyperglycemia. Using this new approach, we demonstrate a dose-dependent effect of STZ on circulating glucose and insulin levels as well as glucose tolerance, while retaining a state of obesity. Importantly, we found that insulin secretion in response to a glucose load was present, but reduced in a dose-dependent manner by increasing STZ. In conclusion, we demonstrate a novel method that enables induction of discrete stages of type 2 diabetes in rodents that closely mirrors the different stages of type 2 diabetes in humans.

Aurora kinase B (AurkB) is a serine/threonine protein kinase with a well-characterised role in orchestrating cell division and cytokinesis, and is prominently expressed in healthy proliferating and cancerous cells. However, the role of AurkB in differentiated and non-dividing cells has not been extensively explored. Previously, we have described a significant upregulation of AurkB expression in cultured cortical neurons following an experimental axonal transection. This is somewhat surprising, as AurkB expression is generally associated only with dividing cells Frangini et al. (Mol Cell 51:647–661, 2013); Hegarat et al. (J Cell Biol 195:1103–1113, 2011); Lu et al. (J Biol Chem 283:31785–31790, 2008); Trakala et al. (Cell Cycle 12:1030–1041, 2014). Herein, we present the first description of a role for AurkB in terminally differentiated neurons. AurkB was prominently expressed within post-mitotic neurons of the zebrafish brain and spinal cord. The expression of AurkB varied during the development of the zebrafish spinal motor neurons. Utilising pharmacological and genetic manipulation to impair AurkB activity resulted in truncation and aberrant motor axon morphology, while overexpression of AurkB resulted in extended axonal outgrowth. Further pharmacological inhibition of AurkB activity in regenerating axons delayed their recovery following UV laser-mediated injury. Collectively, these results suggest a hitherto unreported role of AurkB in regulating neuronal development and axonal outgrowth.