These results point out that GSK3β hyperactivity, and then NFTs formation, could come into function at an early stage of the disease and then turn off at the last stages.

Schwann cells (SC) are characterized by a remarkable plasticity that enables them to promptly respond to nerve injury promoting axonal regeneration. In peripheral nerves after damage SC convert to a repair-promoting phenotype activating a sequence of supportive functions that drive myelin clearance, prevent neuronal death, and help axon growth and guidance. Regeneration of peripheral nerves after damage correlates inversely with thrombin levels. Thrombin is not only the key regulator of the coagulation cascade but also a protease with hormone-like activities that affects various cells of the central and peripheral nervous system mainly through the protease-activated receptor 1 (PAR1). Aim of the present study was to investigate if and how thrombin could affect the axon supportive functions of SC. In particular, our results show that the activation of PAR1 in rat SC cultures with low levels of thrombin or PAR1 agonist peptides induces the release of molecules, which favor neuronal survival and neurite elongation. Conversely, the stimulation of SC with high levels of thrombin or PAR1 agonist peptides drives an opposite effect inducing SC to release factors that inhibit the extension of neurites. Moreover, high levels of thrombin administered to sciatic nerve ex vivo explants induce a dramatic change in SC morphology causing disappearance of the Cajal bands, enlargement of the Schmidt-Lanterman incisures and calcium-mediated demyelination of the paranodes. Our results indicate thrombin as a novel modulator of SC plasticity potentially able to favor or inhibit SC pro-regenerative properties according to its level at the site of lesion.

No abstract

Trimethyltin (TMT) is a highly toxic molecule present as an environmental contaminant causing neurodegeneration particularly of the limbic system both in humans and in rodents. We recently described the occurrence of impairment in the late stages of autophagy in TMT-intoxicated astrocytes. Here we show that similarly to astrocytes also in microglia, TMT induces the precocious block of autophagy indicated by the accumulation of the autophagosome marker, microtubule associated protein light chain 3. Consistent with autophagy impairment we observe in TMT-treated microglia the accumulation of p62/SQSTM1, a protein specifically degraded through this pathway. Lithium has been proved effective in limiting neurodegenerations and, in particular, in ameliorating symptoms of TMT intoxication in rodents. In our in vitro model, lithium displays a pro-survival and anti-inflammatory action reducing both cell death and the proinflammatory response of TMT-treated microglia. In particular, lithium exerts these activities without reducing TMT-induced accumulation of light chain 3 protein. In fact, the autophagic block imposed by TMT is unaffected by lithium administration. These results are of interest as defects in the execution of autophagy are frequently observed in neurodegenerative diseases and lithium is considered a promising therapeutic agent for these pathologies. Thus, it is relevant that this cation can still maintain its pro-survival and anti-inflammatory role in conditions of autophagy block. Copyright © 2016 John Wiley & Sons, Ltd.

Recent evidence highlights the protective role of reelin against amyloid β (Aβ)-induced synaptic dysfunction and cognitive impairment in Alzheimer disease (AD). In this study, exploiting TgCRND8 mice that overexpress a mutant form of amyloid β precursor protein (AβPP) and display an early onset of AD neuropathological signs, we addressed the question whether changes of reelin expression eventually precede the appearance of Aβ-plaques in a sex-dependent manner. We show that sex-associated and brain region-specific differences in reelin expression appear long before Aβ-plaque formation. However, in spite of a downregulation of reelin expression compared to males, TgCRND8 females display fewer Aβ-plaques, suggesting that additional factors, other than sex and reelin level, influence amyloidosis in this mouse model.