Sequential therapy of anti-Nogo-A antibody treatment and treadmill training leads to cumulative improvements after spinal cord injury in rats

Intense training is the most clinically successful treatment modality following incomplete spinal cord injuries (SCIs). With the advent of plasticity enhancing treatments, understanding how treatments might interact when delivered in combination becomes critical. Here, we investigated a rational approach to sequentially combine treadmill locomotor training with antibody mediated suppression of the fiber growth inhibitory protein Nogo-A. Following a large but incomplete thoracic lesion, rats were immediately treated with either anti-Nogo-A or control antibody (2 weeks) and then either left untrained or step-trained starting 3 weeks after injury for 8 weeks. It was found that sequentially combined therapy improved step consistency and reduced toe dragging and climbing errors, as seen with training and anti-Nogo-A individually. Animals with sequential therapy also adopted a more parallel paw position during bipedal walking and showed greater overall quadrupedal locomotor recovery than individual treatments. Histologically, sequential therapy induced the greatest corticospinal tract sprouting caudally into the lumbar region and increased the number of serotonergic synapses onto lumbar motoneurons. Increased primary afferent sprouting and synapse formation onto lumbar motoneurons observed with anti-Nogo-A antibody were reduced by training. Animals with sequential therapy also showed the highest reduction of lumbar interneuronal activity associated with walking (c-fos expression). No treatment effects for thermal nociception, mechanical allodynia, or lesion volume were observed. The results demonstrate that sequential administration of anti-Nogo-A antibody followed in time with intensive locomotor training leads to superior recovery of lost locomotor functions, which is probably mediated by changes in the interaction between descending sprouting and local segmental networks after SCI

Chondroitin 6-sulphate is required for neuroplasticity and memory in ageing

Perineuronal nets (PNNs) are chondroitin sulphate proteoglycan-containing structures on the neuronal surface that have been implicated in the control of neuroplasticity and memory. Age-related reduction of chondroitin 6-sulphates (C6S) leads to PNNs becoming more inhibitory. Here, we investigated whether manipulation of the chondroitin sulphate (CS) composition of the PNNs could restore neuroplasticity and alleviate memory deficits in aged mice. We first confirmed that aged mice (20-months) showed memory and plasticity deficits. They were able to retain or regain their cognitive ability when CSs were digested or PNNs were attenuated. We then explored the role of C6S in memory and neuroplasticity. Transgenic deletion of chondroitin 6-sulfotransferase (chst3) led to a reduction of permissive C6S, simulating aged brains. These animals showed very early memory loss at 11 weeks old. Importantly, restoring C6S levels in aged animals rescued the memory deficits and restored cortical long-term potentiation, suggesting a strategy to improve age-related memory impairment

Repressor element 1-silencing transcription factor drives the development of chronic pain states

Chronic pain is an unmet clinical problem with vast individual, societal and economic impact. Pathologic activity of the peripheral somatosensory afferents is one of the major drivers of chronic pain. This overexcitable state of somatosensory neurons is, in part, produced by the dysregulation of genes controlling neuronal excitability. Despite intense research, a unifying theory behind neuropathic remodelling is lacking. Here we show that transcriptional suppressor, repressor element 1-silencing transcription factor (REST, NRSF), is necessary and sufficient for the development of hyperalgesic state following chronic nerve injury or inflammation. Viral overexpression of REST in mouse DRG induced prominent mechanical and thermal hyperalgesia in vivo. Sensory neuron specific, inducible Rest knock-out prevented the development of such hyperalgesic state in three different chronic pain models. Genetic deletion of Rest reverted injury-induced hyperalgesia. Moreover, viral overexpression of REST in the same neurons in which its gene has been genetically deleted restored neuropathic hyperalgesia. Finally, sensory neuron specific Rest knockout prevented injury-induced downregulation of REST target genes in DRG neurons. This work identified REST as a major regulator of peripheral somatosensory neuron remodelling leading to chronic pain. The findings might help to develop a novel therapeutic approaches to combat chronic pain.This is an open access article distributed under the terms of the Creative Commons Attribution License 4.0 (CC BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

Designer Gene Delivery Vectors: Molecular Engineering and Evolution of Adeno-Associated Viral Vectors for Enhanced Gene Transfer

Gene delivery vectors based on adeno-associated virus (AAV) are highly promising due to several desirable features of this parent virus, including a lack of pathogenicity, efficient infection of dividing and non-dividing cells, and sustained maintenance of the viral genome. However, several problems should be addressed to enhance the utility of AAV vectors, particularly those based on AAV2, the best characterized AAV serotype. First, altering viral tropism would be advantageous for broadening its utility in various tissue or cell types. In response to this need, vector pseudotyping, mosaic capsids, and targeting ligand insertion into the capsid have shown promise for altering AAV specificity. In addition, library selection and directed evolution have recently emerged as promising approaches to modulate AAV tropism despite limited knowledge of viral structure–function relationships. Second, pre-existing immunity to AAV must be addressed for successful clinical application of AAV vectors. “Shielding” polymers, site-directed mutagenesis, and alternative AAV serotypes have shown success in avoiding immune neutralization. Furthermore, directed evolution of the AAV capsid is a high throughput approach that has yielded vectors with substantial resistance to neutralizing antibodies. Molecular engineering and directed evolution of AAV vectors therefore offer promise for generating ‘designer’ gene delivery vectors with enhanced properties

Regulation of CNS plasticity through the extracellular matrix

Contrary to established dogma, the central nervous system (CNS) has a capacity for regeneration and is moderately plastic. Traditionally, such changes have been recognized through development, but more recently, this has been documented in adults through learning and memory or during the advent of trauma and disease. One of the causes of such plasticity has been related to changes in the extracellular matrix (ECM). This complex scaffold of sugars and proteins in the extracellular space alters functionality of the surrounding tissue through moderation of synaptic connections, neurotransmission, ion diffusion, and modification to the cytoskeleton. This chapter discusses the role of the ECM in CNS plasticity in development and the adult. Further, it determines how the ECM affects normal neuronal functioning in critical processes such as memory. Finally, the chapter assesses how the ECM contributes to adverse CNS changes in injury and disease, concentrating on how this matrix may be targeted for therapeutic intervention

Impact de la lisibilité des intersections en rase campagne sur la prise d'information : Effet de l'expérience de conduite

Rapport de rechercheCe travail vise à analyser l'impact de la lisibilité des intersections en rase campagne sur les comportements de conduite. Ces derniers sont étudiés en termes de prise d'information et prise de décision dans les manoeuvres de tourner à gauche. Dans ce cadre, nous nous sommes intéressés plus particulièrement à la population des conducteurs novices et à l'effet des situations de double tâch

Early detection of osteoarthritis in the rat with an antibody specific to type II collagen modified by reactive oxygen species

Background Osteoarthritis (OA) is a disease of the whole joint, with articular cartilage breakdown as a major characteristic. Inflammatory mediators, proteases, and oxidants produced by chondrocytes are known to be responsible for driving cartilage degradation. Nevertheless, the early pathogenic events are still unclear. To investigate this, we employed an antibody that is specific to oxidative post-translationally modified collagen type II (anti-oxPTM-CII) to detect early cartilage pathogenic changes in two rat models of OA. Methods The animals underwent surgery for destabilization of the medial meniscus (DMM) and were sacrificed after 3, 5, 7, 14, and 28 days. Alternatively, anterior cruciate ligament transection with partial meniscectomy (ACLT+pMx) was performed and animals were sacrificed after 1, 3, 5, 7, and 14 days. Joints were stained with toluidine blue and saffron du Gatinais for histological scoring, anti-oxPTM-CII, and anti-collagen type X antibodies (anti-CX). Results We observed positive oxPTM-CII staining as early as 1 or 3 days after ACLT+pMx or DMM surgeries, respectively, before overt cartilage lesions were visible. oxPTM-CII was located mostly in the deep zone of the medial tibial cartilage, in the pericellular and territorial matrix of hypertrophic chondrocytes, and co-localized with CX staining. Staining was weak or absent for the lateral compartment or the contralateral knees except at later time points. Conclusion The results demonstrate that oxidant production and chondrocyte hypertrophy occur very early in the onset of OA, possibly initiating the pathogenic events of OA. We propose to use anti-oxPTM-CII as an early biomarker for OA ahead of radiographic changes

Effect of inhibition of dynein function and microtubule-altering drugs on AAV2 transduction.

AbstractOver the past decade, adeno-associated (AAV) virus has emerged as an important vector for gene therapy. As a result, understanding its basic biology, including intracellular trafficking, has become increasingly important. Here, we describe the effect of inhibiting dynein function or altering the state of microtubule polymerization on rAAV2 transduction. Overexpression of dynamitin, resulting in a functional inhibition of the minus-end-directed microtubule motor protein dynein, did not inhibit transduction. Equally, treatment of cells with nocodazole, or concentrations of vinblastine that result in the disruption of microtubules, had no significant effect on transduction. In contrast, high concentrations of Taxol and vinblastine, resulting in microtubule stabilization and the formation of tubulin paracrystals respectively, reduced rAAV2 transduction in a vector-dose-dependent manner. These results demonstrate that AAV2 can infect HeLa cells independently of dynein function or an intact microtubule network