Alzheimer's disease (AD) is characterized by agglomerated proteins constitued by amyloid-beta (A?). A? possesses neutoxic effect and is also a substrate of tissue transglutaminase (TG2), an ubiquitarian protein that plays a key role in AD. Several reports indicated that in AD is involved oxidative stress and that the treatment with antioxidants mitigates the effects of oxidative stress in the central nervous system. In particular, astaxanthin, an antioxidant with antiflammatory properties, could have an important therapeutic role in AD. Herein, we have evaluated the effect of astaxanthin pretreatment on olfactory ensheathing cells (OECs) exposed to the native peptide of A?(1-42) or its fragments A?(25-35) and A?(35-25). OECs are glial cells located in the olfactory system, the first to show a deficit in neurodegenerative diseases. Vimentin, GFAP, nestin, cyclin D1, TG2 expression and the activation of the apoptotic pathway were assessed through immunocytochemical techniques. The percentage of cell viability and ROS levels were detected. In addition, to monitor the mitochondrial status, we used delayed luminescence (DL). We found that astaxanthin was able to reduce TG2 expression up-regulated by A?, reducing also GFAP and Vimentin levels. Astaxanthin pre-treatment stimulates cellular repair increasing cyclin D1 and nestin levels and inhibing apoptotic pathway activation. In parallel, we observed a significant change of DL intensity in OECs exposed to the toxic fragment A? (25-35), that completely disappear when OECs were pre-incubated with astaxantin. Therefore, we can suggest that astaxanthin pretreatment could represent an innovative mechanism to counteract the aberrant TG2 overexpression in AD.

The involvement of the mGlu5 receptors in the pathophysiology of several forms of monogenic autism has been supported by numerous studies following the seminal observation that mGlu5 receptor-dependent long-term depression was enhanced in the hippocampus of mice modeling the fragile-X syndrome (FXS). Surprisingly, there are no studies examining the canonical signal transduction pathway activated by mGlu5 receptors (i.e. polyphosphoinositide - PI - hydrolysis) in mouse models of autism. We have developed a method for in vivo assessment of PI hydrolysis based on systemic injection of lithium chloride followed by treatment with the selective mGlu5 receptor PAM, VU0360172, and measurement of endogenous inositolmonophosphate (InsP) in brain tissue. Here, we report that mGlu5 receptor-mediated PI hydrolysis was blunted in the cerebral cortex, hippocampus, and corpus striatum of Ube3am-/p+ mice modeling Angelman syndrome (AS), and in the cerebral cortex and hippocampus of Fmr1 knockout mice modeling FXS. In vivo mGlu5 receptor-mediated stimulation of Akt on threonine 308 was also blunted in the hippocampus of FXS mice. These changes were associated with a significant increase in cortical and striatal Homer1 levels and striatal mGlu5 receptor and G & alpha;q levels in AS mice, and with a reduction in cortical mGlu5 receptor and hippocampal G & alpha;q levels, and an increase in cortical phospholipase-C & beta; and hippocampal Homer1 levels in FXS mice. This is the first evidence that the canonical transduction pathway activated by mGlu5 receptors is downregulated in brain regions of mice modeling monogenic autism.

Astaxanthin, a natural compound of Haematococcus pluvialis, possesses antioxidant, antiinflammatory, anti-tumor and immunomodulatory activities. It also represents a potential therapeutic in Alzheimer's disease (AD), that is related to oxidative stress and agglomeration of proteins such as amyloid-beta (A?). A? is a neurotoxic protein and a substrate of tissue transglutaminase (TG2), an ubiquitary protein involved in AD. Herein, the effect of astaxanthin pretreatment on olfactory ensheathing cells (OECs) exposed to A?(1-42) or by A?(25-35) or A?(35-25), and on TG2 expression were assessed. Vimentin, GFAP, nestin, cyclin D1 and caspase-3 were evaluated. ROS levels and the percentage of cell viability were also detected. In parallel, delayed luminescence (DL) was used to monitor mitochondrial status. ASTA reduced TG2, GFAP and vimentin overexpression, inhibiting cyclin D1 levels and apoptotic pathway activation which induced an increase in the nestin levels. In addition, significant changes in DL intensities were particularly observed in OECs exposed to A? toxic fragment (25-35), that completely disappear when OECs were pre-incubated in astaxantin. Therefore, we suggest that ASTA pre-treatment might represent an innovative mechanism to contrast TG2 overexpression in AD.

Alzhèimer Disease (AD), one of the most common neurodegenerative diseases, is characterized by progressive neuronal loss and accumulation of neurotoxic proteins, including Amyloid-beta (A?). It is known that tissue transglutaminase (TG2), an ubiquitary calcium-dependent protein, is involved in protein aggregation in AD. Previous our studies showed that A?(1-42) and its fragments A?(25-35) and A?(35-25) induced an overexpression of TG2 on Olfactory Ensheathing Cells (OECs), a glial population of the olfactory system that express neural stem cell markers, including Nestin. In the last years, growing attention rose on neuronutraceutics and their effect on mental health. Among these molecules, we focused our research on indicaxanthin and astaxanthin, natural compounds that are able to cross the blood-brain barrier. In this study, the effect of indicaxanthin or astaxanthin pre-treatment on TG2 expression in OECs exposed to A? was immunocytochemically evaluated by Vimentin and Glial Fibrillary Acid Protein (GFAP) expression. The percentage of cell viability by MTT test and the apoptotic pathway activation were also evaluated. Since Nestin, a marker of neural precursors, is co-expressed in pluripotent stem cells with cyclin D1, a marker of cellular proliferation, the effect of indicaxanthin and astaxanthin pre-treatment on their expression was also tested. We found that indicaxanthin or astaxanthin pre-treatment was able to reduce TG2 overexpression, decreasing GFAP and Vimentin levels. In addition, both compounds inhibited apoptotic pathway activation and induced an increase in the Nestin and cyclin D1 expression. These results show that indicaxanthin and astaxanthin are able to prevent the TG2 change conformation induced by A?. Our data demonstrate that indicaxanthin or astaxanthin pre-treatment stimulated OECs self-renewal through the reparative activity played by TG2. Therefore, indicaxanthin and astaxanthin might represent an innovative mechanism to contrast TG2 overexpression in AD

Alzhèimer Disease (AD), one of the most common neurodegenerative diseases, is characterized by progressive neuronal loss and accumulation of proteins, including Amyloid-beta (A?), a neurotoxic protein. It is known that tissue transglutaminase (TG2), an ubiquitary calcium-dependent protein, is involved in protein aggregation in AD. Previous our studies showed that A?(1-42) and its fragments A?(25-35) and A?(35-25) induced an overexpression of TG2 and its isoforms on Olfactory Ensheathing Cells (OECs), a glial population of the olfactory system that express neural stem cell markers, including Nestin. In the last years growing attention rose on neuronutraceutics and their effect on mental health. Among these molecules, we focused our research on indicaxanthin, and astaxanthin, natural compounds that were able to cross the blood-brain barrier. In this study, the effect of indicaxanthin or astaxanthin pre-treatment on TG2 and its isoform expression levels exposed to A?(1-42) or by A?(25-35) or A?(35-25) on OECs was assessed. Furthermore, we evaluated thei effect on the expression levels of Vimentin and Glial Fibrillary Acid Protein (GFAP). The percentage of cell viability and the apoptotic pathway activation were also evaluated. Since Nestin, a marker of neural precursors, is co-expressed in pluripotent stem cells with cyclin D1, a marker of cellular proliferation, the effect of indicaxanthin and astaxanthin pre-treatment on their expression levels was also tested. In addition, the production of total reactive oxygen species (ROS) and superoxide anion (O2-.), were assessed. In parallel, docking studies were performed to obtain informations relative to the interaction between the indicaxanthin or astaxanthin and TG2. We found that indicaxanthin or astaxanthin pre-treatment was able to reduce TG2 overexpression and its isoforms, decreasing total ROS and O2-.production and GFAP and Vimentin expression levels. In addition, they inhibited apoptotic pathway activation and induced an increase in the Nestin and cyclin D1 expression levels. Docking results showing that indicaxanthin and astaxanthin were able to prevent the TG2 change conformation induced by A?. Our data demonstrated that indicaxanthin or astaxanthin pre-treatment stimulated OECs self-renewal through the reparative activity played by TG2. Therefore, indicaxanthin and astaxanthin might represent an innovative mechanism to contrast TG2 overexpression in AD.

Fragile X syndrome (FXS) is the most frequent form of inherited intellectual disability and a leading monogenic cause of autism. FXS is caused by the silencing of the fragile X mental retardation 1 (FMR1) gene expression and ensuing lack of the fragile X mental retardation protein (FMRP), an RNA binding protein involved in several aspect of RNA metabolism, including mRNA transport and translation. Consequently, abnormal expression of proteins at synapses may underlie brain dysfunction in FXS. FMRP is also implicated in DNA damage response (DDR) and is a component of stress granules (SGs), cytoplasmic aggregates containing translation initiation components and many additional proteins affecting mRNA function. Upon cellular stress, global protein synthesis is blocked, and mRNAs are temporarily recruited into SGs, which are thought to serve as sites of mRNA storage or triage. Evidence in the Fmr1 knockout mouse model of FXS suggests increased oxidative stress in the brain and higher susceptibility to apoptosis. In this study we tested the appearance of SGs and the cell survival in wild-type (WT) and Fmr1 knockout (KO) cultured astrocytes after exposure to sodium arsenite and hydrogen peroxide, by using immunocytochemistry with an anti-G3DP1 antibody recognizing SGs and MTT assay. We observed an increased number of cells with SGs after exposure to oxidative stress, as expected; however, we detected a lower number of cells with SGs in Fmr1 KO than WT astrocytes both under basal condition and after exposure to oxidative stress. Interestingly, we also detected a lower cell survival in Fmr1 KO than WT astrocytes upon exposure to oxidative stress. These results indicate that the lack of FMRP impairs the formation of SGs and sensitizes to oxidative stress induced damage in astrocytes, disclosing a contribution of this cell type to brain dysfunction in FXS.

Background: The study of consciousness has always been considered a challenge for neonatologists, even more when considering the uterine period. Our review aimed to individuate at what gestational age the fetus, which later became a premature infant, can feel the perception of external stimuli. Therefore, the aim of our review was to study the onset of consciousness during the fetal life. Materials and methods: A literature search was performed in Medline-PubMed database. We included all papers found with the following MeSH words: "consciousness or cognition or awareness or comprehension or cognitive or consciousness of pain" in combination with "embryo or fetus or fetal life or newborn." Studies were selected if titles and/or abstracts suggested an association between formation of consciousness (the basics of neurodevelopment) and preterm infant or fetus. Titles and abstracts were first screened by three independent reviewers according to Cochrane Collaboration's recommendations. Results: From the literature review, we found only 8 papers describing the onset of consciousness in the transition period from fetus to premature newborn. Therefore, according to these papers, we temporally analyzed the formation of the thalamocortical connections that are the basis of consciousness. Conclusions: We can conclude that from a neuroanatomical point of view, it is rather unlikely that the infant can be seen as a conscious human before 24 weeks of gestational age, thus before all the thalamocortical connections are established. Further literature data have to confirm this hypothesis.

Graph theoretical studies have been designed to investigate network topologies during life. Network science and graph theory methods may contribute to a better understanding of brain function, both normal and abnormal, throughout developmental stages. The degree to which childhood epilepsies exert a significant effect on brain network organisation and cognition remains unclear. The hypothesis suggests that the formation of abnormal networks associated with epileptogenesis early in life causes a disruption in normal brain network development and cognition, reflecting abnormalities in later life. Neurological diseases with onset during critical stages of brain maturation, including childhood epilepsy, may threaten this orderly neurodevelopmental process. According to the hypothesis that the formation of abnormal networks associated with epileptogenesis in early life causes a disruption in normal brain network development, it is then mandatory to perform a proper examination of children with new-onset epilepsy early in the disease course and a deep study of their brain network organisation over time. In regards, graph theoretical analysis could add more information. In order to facilitate further development of graph theory in childhood, we performed a systematic review to describe its application in functional dynamic connectivity using electroencephalographic (EEG) analysis, focussing on paediatric epilepsy.

Alzheimer Disease (AD), one of the most common neurodegenerative diseases, is characterized by progressive neuronal loss and accumulation of proteins, including Amyloid-beta (A?), a neurotoxic protein. It is known that tissue transglutaminase (TG2), an ubiquitary calcium-dependent protein, is involved in protein aggregation in AD. Previous our studies showed that A?(1-42) and its fragments A?(25-35) and A?(35-25) induced an overexpression of TG2 and its isoforms on Olfactory Ensheathing Cells (OECs), a glial population of the olfactory system expressing neural stem cell markers, including Nestin. In the last years growing attention rose on neuronutraceutics and their effect on mental health, as many compounds are characterized by antioxidant and anti-inflammatory activities, these properties could have beneficial effects in counteracting the multifactorial onset and progression of AD. Among these molecules, we focus on Astaxanthin, a natural compound predominantly found in marine organisms, the green microalgae Haematococcus pluvialis and Chlorella zofingiensis; it can be transported into the brain through the blood-brain barrier and exhibits powerful anti-oxidant activity. In addition, Astaxanthin can effectively scavenge intracellular free radicals and destroy peroxide chain reactions, protecting cell and biological membranes from oxidative damage. Therefore, it exhibits numerous health benefits, such as anti-inflammatory actions, anti-tumor effects, hepatoprotective effects, and immunomodulatory activity. In this study, the effect of Astaxanthin pretreatment on TG2 and its isoform expression exposed to A?(1-42) or by A?(25-35) or A?(35-25) on OECs was assessed. Moreover, we evaluated Astaxanthin effect on the expression of some cytoskeletal proteins, Vimentin, Glial Fibrillary Acid Protein (GFAP), Nestin and Caspase-3. Astaxanthin pre-treatment reduced TG2 overexpression, modulating the level of TG2 isoforms and reduced ROS production, GFAP and Vimentin expression, inhibiting apoptotic pathway activation and induced an increase in the Nestin levels. Our data demonstrated that Astaxanthin pre-treatment stimulated OECs self-renewal through the reparative activity played by TG2. Therefore, pre-treatment Astaxanthin might represent an innovative mechanism to contrast TG2 overexpression in AD.

Fragile X syndrome (FXS) is a common form of intellectual disability and autism caused by the lack of Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein involved in RNA transport and protein synthesis. Upon cellular stress, global protein synthesis is blocked and mRNAs are recruited into stress granules (SGs), together with RNA-binding proteins including FMRP. Activation of group-I metabotropic glutamate (mGlu) receptors stimulates FMRP-mediated mRNA transport and protein synthesis, but their role in SGs formation is unexplored. To this aim, we pre-treated wild type (WT) and Fmr1 knockout (KO) cultured astrocytes with the group-I-mGlu receptor agonist (S)-3,5-Dihydroxyphenylglycine (DHPG) and exposed them to sodium arsenite (NaAsO), a widely used inducer of SGs formation. In WT cultures the activation of group-I mGlu receptors reduced SGs formation and recruitment of FMRP into SGs, and also attenuated phosphorylation of eIF2?, a key event crucially involved in SGs formation and inhibition of protein synthesis. In contrast, Fmr1 KO astrocytes, which exhibited a lower number of SGs than WT astrocytes, did not respond to agonist stimulation. Interestingly, the mGlu5 receptor negative allosteric modulator (NAM) 2-methyl-6-(phenylethynyl)pyridine (MPEP) antagonized DHPG-mediated SGs reduction in WT and reversed SGs formation in Fmr1 KO cultures. Our findings reveal a novel function of mGlu5 receptor as modulator of SGs formation and open new perspectives for understanding cellular response to stress in FXS pathophysiology.

Herein, we assessed the effect of full native peptide of amyloid-beta (A?) (1-42) and its frag-ments (25-35 and 35-25) on tissue transglutaminase (TG2) and its isoforms (TG2-Long and TG2-Short) expression levels on Olfactory Ensheathing Cells (OECs). Vimentin and Glial Fibril-lary Acid Protein (GFAP) were also studied. The effect of the pre-treatment with Indicaxanthin from Opuntia ficus-indica fruit on TG2 expression levels and its isoforms, cell viability, total Reactive Oxygen Species (ROS), superoxide anion (O2-) and apoptotic pathway activation was assessed. The levels of Nestin and cyclin D1 were also evaluated. Our findings highlight that OECs exposure to A?(1-42) and its fragments induced an increase of TG2 expression levels and a different expression pattern of its isoforms. Indicaxanthin pre-treatment reduced TG2 over-expression modulating the expression of TG2 isoforms. It reduced total ROS and O2- pro-duction, GFAP and Vimentin levels, inhibiting apoptotic pathway activation. It also induced an increase of Nestin and cyclin D1 expression levels. Our data demonstrate that Indicaxanthin pre-treatment stimulated OECs self-renewal through the reparative activity played by TG2. They also suggest that A? might modify TG2 conformation in OECs and that Indicaxanthin pre-treatment might modulate TG2 conformation, stimulating neural regeneration in Alzhèimer Disease.

Herein, we assessed the effect of Ferulic Acid (FA), a natural antioxidant with anti-cancer effect, on the human glioblastoma cells through molecular and Delayed Luminescence (DL) studies. DL, a phenomenon of ultra-week emission of optical photons, was used to monitor mitochondrial assessment. The effect of FA loaded in nanostructured lipid carriers (NLCs) was also assessed. To validate NLCs as a drug delivery system for glioblastoma treatment, particular attention was focused on their effect. We found that free FA induced a significant decrease in c-Myc and Bcl-2 expression levels accompanied by the apoptotic pathway activation. Blank NLCs, even if they did not induce cytotoxicity and caspase-3 cleavage, decreased Bcl-2, ERK1/2, c-Myc expression levels activating PARP-1 cleavage. The changes in DL intensity and kinetics highlighted a possible effect of nanoparticle matrix on mitochondria, through the involvement of the NADH pool and ROS production that, in turn, activates ERK1/2 pathways. All the effects on protein expression levels and on the activation of apoptotic pathway appeared more evident when the cells were exposed to FA loaded in NLCs. We demonstrated that the observed effects are due to a synergic pro-apoptotic influence exerted by FA, whose bio-availability increases in the glioblastoma cells, and NLCs formulation.

Metabotropic glutamate receptor subtype 5 (mGluR5) is crucially implicated in the pathophysiology of Fragile X Syndrome (FXS); however, its dysfunction at the sub-cellular level, and related synaptic and cognitive phenotypes are unexplored. Here, we probed the consequences of mGluR5/Homer scaffold disruption for mGluR5 cell-surface mobility, synaptic N-methyl-D-Aspartate receptor (NMDAR) function, and behavioral phenotypes in the second-generation Fmr1 knockout (KO) mouse. Using single-molecule tracking, we found that mGluR5 was significantly more mobile at synapses in hippocampal Fmr1 KO neurons, causing an increased synaptic surface co-clustering of mGluR5 and NMDAR. This correlated with a reduced amplitude of synaptic NMDAR currents, a lack of their mGluR5-Activated long-Term depression, and NMDAR/hippocampus dependent cognitive deficits. These synaptic and behavioral phenomena were reversed by knocking down Homer1a in Fmr1 KO mice. Our study provides a mechanistic link between changes of mGluR5 dynamics and pathological phenotypes of FXS, unveiling novel targets for mGluR5-based therapeutics.

Endothelin-1 (ET-1) is a vasoactive peptide produced by activated astrocytes and microglia and is implicated in initiating and sustaining reactive gliosis in neurodegenerative diseases. We have previously suggested that ET-1 can play a role in the pathophysiology of amyotrophic lateral sclerosis (ALS). Indeed, we reported that this peptide is abundantly expressed in reactive astrocytes in the spinal cord of SOD1-G93A mice and ALS patients and exerts a toxic effect on motor neurons (MNs) in an in vitro model of mixed spinal cord cultures enriched with reactive astrocytes. Here, we explored the possible mechanisms underlying the toxic effect of ET-1 on cultured MNs. We show that ET-1 toxicity is not directly caused by oxidative stress or activation of cyclooxygenase-2 but requires the synthesis of nitric oxide and is mediated by a reduced activation of the phosphoinositide 3-kinase pathway. Furthermore, we observed that ET-1 is also toxic for microglia, although its effect on MNs is independent of the presence of this type of glial cells. Our study confirms that ET-1 may contribute to MN death and corroborates the view that the modulation of ET-1 signaling might be a therapeutic strategy to slow down MN degeneration in ALS.

Herein, we assessed in a particular glial cell type, called olfactory ensheathing cells (OECs), the effect of some growth factors (GFs) on tissue transglutaminase (TG2) overexpression induced by amyloid-beta (A?) with native full-length peptide 1-42 or by fragments, 25-35 or 35-25, as control. Previously, we demonstrated that TG2 overexpression induced by some stressors was down-regulated by GFs exposure in OECs. To monitor cell viability, an MTT test was used, while TG2 expression was examined using immunocytochemical and Western blot analysis. We also considered the involvement of the TG2-mediated apoptotic pathway. Vimentin expression was evaluated as well. Reactive oxygen species and reduced glutathione levels were utilized to test the oxidative intracellular status. Lactate dehydrogenase released into the medium, as a marker of necrotic cell death, was evaluated. We found that in OECs exposed to A?(1-42) or A?(25-35) for 24 h, TG2 expression increased, and we observed that the protein appeared prevalently localized in the cytosol. The pre-treatment with GFs, basic fibroblast growth factor (bFGF) or glial-derived neurotrophic factor (GDNF), down-regulated the TG2 level, which was prevalently limited to the nuclear compartment. Vimentin expression and caspase cleavage showed a significant enhancement in A?(1-42) and A?(25-35) exposed cells. The pre-treatment with bFGF or GDNF was able to restore the levels of the proteins to control values, and the intracellular oxidative status modified by the exposure to A?(1-42) or A?(25-35). Our data suggest that both bFGF or GDNF could be an innovative mechanism to contrast TG2 expression, which plays a key role in Alzheimer's disease.

Fragile X Syndrome (FXS) is the most common form of inherited intellectual disability, frequently associated with epilepsy and autism. Fmr1 KO mice, a model of FXS, display excessive metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD), altered dendritic spine morphology, learning deficit and autistic behavior. We have shown that 5-HT7 receptor (5-HT7R) agonists reverse mGluR-LTD in wt and Fmr1 KO mice (Costa et al., Biol. Psych. 2012, 72:924-933). We have preliminary data showing that 5-HT7R agonists also rescue dendritic spine morphology, learning and behavior in Fmr1KO mice, suggesting that they might become a novel therapeutic strategy for FXS. To identify the mechanisms underlying 5-HT7R-mediated effects, we used patch clamp on hippocampal slices from wild-type (wt) and Fmr1 KO mice to test the effects of 5-HT7R agonists on mGluR-LTD in the presence of specific blockers of intracellular messengers. LP-211, a selective 5-HT7 R agonist, reversed mGluR-LTD in the CA3-CA1 synapse in wt and Fmr1 KO slices. The effect of LP-211 was mimicked by forskolin and was abolished by the adenylate cyclase inhibitor SQ22536. The effect of LP-211 persisted in the presence of cAMPS-Rp or PKA inhibitor peptide fragment 6-22 (PKA inhibitors) or PD98059 (a MEK/ERK inhibitor), but was reduced in the presence of lithium (a PI3K/GSK3 inhibitor) and was completely abolished in the presence of SB216763 (a GSK3 inhibitor), roscovitine (a Cdk5 inhibitor) or anisomycin (a protein translation inhibitor). Taken together our data show that 5-HT7 receptor activation reverses mGluR-LTD acting through a cAMP-dependent mechanism involving Cdk5 and GSK3 kinases and protein synthesis; we are currently investigating at which level these pathways interact.

In the U87-MG glioma cell line we assessed the effect of unloaded/NLC-loaded FA on the TG2-mediated apoptotic pathway activation, and cell cycle progression.

La transglutaminasi Tissutale (TG2) è una proteina coinvolta in molti processi fisiologici e patologici, tra cui sopravvivenza cellulare, differenziazione, apoptosi, tumori e malattie neurodegenerative, come la malattia di Parkinson e di Alzheimer (AD). L' attività della TG2 è stata rilevata sia in condizioni normali sia in pazienti con AD ed è emerso che è coinvolta nello sviluppo di neurofilamenti anormali. Qui abbiamo valutato l'effetto di alcuni fattori trofici, il bFGF ed il GDNF, sull'espressione della TG2 indotta da beta-amiloide (?A) in cellule gliali olfattive (OECs). E' noto che ?A è un substrato per TG2 e che i fattori trofici regolano i livelli di espressione. Le OECs sono cellule gliali responsabili di capacità rigenerative e di fenomeni di plasticità. Sono stati usati test di vitalità cellulare, procedure di immunocitochimica e Western Blot. I nostri studi hanno dimostrato che nelle OECs esposte a ?A per 24 h, l'espressione della TG2 risultava aumentato; quando le cellule venivano pre-trattate con bFGF o GDNF il livello della TG2 diminuiva. Abbiamo anche valutato l'espressione sia della Vimentina sia della Caspasi, che risultavano espresse quando esposte alla ?A, mentre se trattate con il bFGF o GDNF si ripristinavano i livelli di proteine e lo stato ossidativo intracellulare. Pertanto, i nostri dati suggeriscono che bFGF o GDNF, potrebbero rappresentare un meccanismo innovativo per contrastare l'espressione della TG2, che svolge un ruolo chiave nel AD.

Introduction. Olfactory mucosa is considered a potential source of neural stem cells, since supported by peculiar glial cells, Olfactory Ensheathing Cells (OECs). Studies have shown that OECs share some common features with astrocytes and Schwann Cells (Ramon-Cueto and Avila 1998). The finding that OECs are a source of multiple Growth Factors (GFs) is very important as they play a decisive role in regeneration, promoting functional restoration in lesioned area (Raisman and Li 2007). Immunocytochemical investigations have reported that OECs express different markers and adhesion molecules (Pellitteri et. al., 2010). Therefore, OECs have attracted attention because of their remarkable neural plasticity. Materials and Methods. Primary OECs were prepared from neonatal rat olfactory bulbs. In some experiments were used GFs. Cells were identified by immunocytochemical procedures, using different antibodies and the results were highlighted by fluorescent microscopy. Results. Our in vitro studies have reported the ability of OECs to stimulate neuronal survival and neurite sprouting mediated through secretion of GFs; moreover, OECs have shown the capability to exert a protective effect on neurons exposed to stressed condition, such as hypoxia, simulating secondary events during spinal cord injury. Conclusion. These data suggest that OECs might be a suitable tool in cellular therapy for their exceptional ability to promote axonal regeneration and functional restoration making them attractive candidates for neurogenesis, in different neurological disorders or injured CNS.

Tissue transglutaminase (TG2) is a calcium dependent protein implicated in numerous physiological and pathological cellular processes, including some neurodegenerative diseases, such as Alzheimer disease (AD). TG2 activity has been detected in normal and AD brains and it is involved in development of abnormal insoluble neurofilaments. Furthermore, it has been demonstrated that Amyloid-beta (A?) is a substrate for TG2, which is a reactive acceptor and donor sites responsible for the TG-catalysed formation of polymers. In previous studies, we demonstrated a relationship between TG2 and Growth Factors (GFs) in a particular glial cell type, Olfactory Ensheathing Cells (OECs). Specifically, we showed that TG2 overexpression induced by some stressors was down-regulated by GFs exposure in OECs. To monitor cell viability, MTT test was used, while TG2 expression was examined by immunocytochemical and Western Blot analysis. We also considered the involvement of the apoptotic pathway-TG2 mediated. Vimentin expression was also evaluated. We found that in OECs exposed to A? for 24 h, TG2 expression increased, and we observed that the protein appeared prevalently localized in the cytosol. The pre-treatment with GFs down-regulated the TG2 level, which was prevalently limited into the nuclear compartment. Vimentin expression and Caspase cleavage showed a significant enhance in A? exposed cells. The pre-treatment with GFs was able to restore the levels of the proteins to control values, and the intracellular oxidative status modified by the exposure to A?. Our data suggest that GFs could be an innovative mechanism to contrast TG2 expression, which plays a key role in AD.