Neuroscience
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Therapeutic strategies for the fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS) are actually minimally effective on patients' survival and quality of life. Although stem cell therapy has raised great expectations, information on the involved molecular mechanisms is still limited. Here we assessed the efficacy of the systemic administration of adipose-derived mesenchymal stem cells (ASC), a previously untested stem cell population, in superoxide-dismutase 1 (SOD1)-mutant transgenic mice, the animal model of familial ALS. ⋯ By examining the spinal cord tissue factors that may prolong neuronal survival, we found a significant up-regulation in levels of glial-derived neurotrophic factor (GDNF) and basic fibroblast growth factor (bFGF) after ASC treatment. Considering that ASC produce bFGF but not GDNF, these findings indicate that ASC may promote neuroprotection either directly and/or by modulating the secretome of local glial cells toward a neuroprotective phenotype. Such neuroprotection resulted in a strong and long-lasting effect on motor performance and encourages the use of ASC in human pathologies, in which current therapies are not able to maintain a satisfying neurological functional status.
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Tropisetron, a selective 5-HT3 receptor (5-HT3R) antagonist, has been widely used to counteract chemotherapy-induced emesis. New investigations described the immunomodulatory properties of tropisetron which may not be 5HT3R mediated. In the present study, we assessed the potential effects of tropisetron on an animal model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis (EAE). ⋯ Concurrent administration of tropisetron and mCPBG did not significantly alter the histological damage in the spinal cord. mCPBG had no effect on the mentioned parameters. Taken together, these findings indicate that tropisetron has considerable immunoregulatory functions in EAE and may be promising for the treatment of MS or other autoimmune and inflammatory diseases of the CNS. Furthermore, beneficial effects of tropisetron in this setting seem to be both receptor dependent and receptor independent in the early phase of the disease.
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Acoustic trauma, a leading cause of sensorineural hearing loss in adults, induces a complex degenerative process in the cochlea. Although previous investigations have identified multiple stress pathways, a comprehensive analysis of cochlear responses to acoustic injury is still lacking. In the current study, we used the next-generation RNA-sequencing (RNA-Seq) technique to sequence the whole transcriptome of the normal and noise-traumatized cochlear sensory epithelia (CSE). ⋯ Moreover, protein expression analysis revealed strong expression of Cfi and C1s proteins in the organ of Corti. Importantly, these proteins exhibited expression changes following acoustic trauma. Collectively, the results of the current investigation suggest the involvement of the complement components in cochlear responses to acoustic trauma.
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Recently, we have shown the expression of novel chemoreceptors corresponding to the olfactory receptor (OR) and taste receptor (TASR) families in the human brain. We have also shown dysregulation of ORs and TASRs in the cerebral cortex in Parkinson's disease. The present study demonstrates the presence of OR mRNA and mRNA of obligated downstream components of OR signaling adenylyl cyclase 3 (ADYLC3) and olfactory G protein (Gnal) in the cerebral cortex of the mouse. ⋯ Altered OR, ADYLC3 and Gnal mRNA expression with disease progression has also been found in APP/PS1 transgenic mice, used as a model of AD. The function of these orphan receptors is not known, but probably related to cell signaling pathways responding to unidentified ligands. Variability in the drift, either down- or up-regulation, of dysregulated genes, suggests that central ORs and TASRs are vulnerable to variegated neurodegenerative diseases with cortical involvement, and that altered expression of ORs and TASRs is not a mere reflection of neuronal loss but rather a modulated pathological response.
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Crush injuries of peripheral nerves typically lead to axonotmesis, axonal damage without disruption of connective tissue sheaths. Generally, human patients and experimental animals recover well after axonotmesis and the favorable outcome has been attributed to precise axonal reinnervation of the original peripheral targets. Here we assessed functionally and morphologically the long-term consequences of facial nerve axonotmesis in rats. ⋯ Morphological analyses showed that the facial motoneurons ipsilateral to injury were innervated by lower numbers of glutamatergic terminals (-15%) and cholinergic perisomatic boutons (-26%) compared with the contralateral non-injured motoneurons. The structural deficits were correlated with functional performance of individual animals and associated with microgliosis in the facial nucleus but not with polyinnervation of muscle fibers. These results support the idea that restricted CNS plasticity and insufficient afferent inputs to motoneurons may substantially contribute to functional deficits after facial nerve injuries, possibly including pathologic conditions in humans like axonotmesis in idiopathic facial nerve (Bell's) palsy.