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In this work we investigate the role of CHIP in a new CHIP-mutation related ataxia and the therapeutic potential of trehalose. The patient's fibroblasts with a new form of hereditary ataxia, related to STUB1 gene (CHIP) mutations, and three age and sex-matched controls were treated with epoxomicin and trehalose. The effects on cell death, protein misfolding and proteostasis were evaluated. Recent studies have revealed that mutations in STUB-1 gene lead to a growing list of molecular defects as deregulation of protein quality, inhibition of proteasome, cell death, decreased autophagy and alteration in CHIP and HSP70 levels. In this CHIP-mutant patient fibroblasts the inhibition of proteasome with epoxomicin induced severe pathophysiological age-associated changes, cell death and protein ubiquitination. Additionally, treatment with epoxomicin produced a dose-dependent increase in the number of cleaved caspase-3 positive cells. However, co-treatment with trehalose, a disaccharide of glucose present in a wide variety of organisms and known as a autophagy enhancer, reduced these pathological events. Trehalose application also increased CHIP and HSP70 expression and GSH free radical levels. Furthermore, trehalose augmented macro and chaperone mediated autophagy (CMA), rising the levels of LC3, LAMP2, CD63 and increasing the expression of Beclin-1 and Atg5-Atg12. Trehalose treatment in addition increased the percentage of immunoreactive cells to HSC70 and LAMP2 and reduced the autophagic substrate, p62. Although this is an individual case based on only one patient and the statistical comparisons are not valid between controls and patient, the low variability among controls and the obvious differences with this patient allow us to conclude that trehalose, through its autophagy activation capacity, anti-aggregation properties, anti-oxidative effects and lack of toxicity, could be very promising for the treatment of CHIP-mutation related ataxia, and possibly a wide spectrum of neurodegenerative disorders related to protein disconformation. [ABSTRACT FROM AUTHOR]

Huntington's disease (HD) is a neurodegenerative disorder characterized by progressive motor, cognitive and psychiatric deficits, associated with predominant loss of striatal neurons and is caused by polyglutamine expansion in the huntingtin protein. Mutant huntingtin protein and its fragments are resistant to protein degradation and produce a blockade of the ubiquitin proteasome system (UPS). In HD models, the proteasome inhibitor epoxomicin aggravates protein accumulation and the inductor of autophagy, trehalose, diminishes it. We have investigated the effects of epoxomicin and trehalose in skin fibroblasts of control and HD patients. Untreated HD fibroblasts have increased the levels of ubiquitinized proteins and higher levels of reactive oxygen species (ROS), huntingtin and the autophagy marker LAMP2A. Baseline replication rates were higher in HD than in controls fibroblasts but that was reverted after 12 passages. Epoxomicin increases the activated caspase-3, HSP70, huntingtin, ubiquitinated proteins and ROS levels in both HD and controls. Treatment with trehalose counteracts the increase in ROS, ubiquitinated proteins, huntingtin and activated caspase-3 levels induced by epoxomicin, and also increases the LC3 levels more in HD fibroblast than controls. These results suggest that trehalose could revert protein processing abnormalities in patients with Huntington's Disease. [ABSTRACT FROM AUTHOR]

Huntington's disease is a neurodegenerative disorder caused by an expansion of CAG repeats in the huntingtin gene which produces widespread neuronal and glial pathology. We here investigated the possible therapeutic role of glia or glial products in Huntington's disease using striatal glial conditioned medium (GCM) from fetus mice (E16) continuously infused for 15 and 30 days with osmotic minipumps into the left striatum of R6/1 mice. Animals infused with GCM had significantly less huntingtin inclusions in the ipsilateral cerebral cortex and in the ipsilateral and contralateral striata than mice infused with cerebrospinal fluid. The numbers of DARPP-32 and TH positive neurons were also greater in the ipsilateral but not contralateral striata and substantia nigra, respectively, suggesting a neuroprotective effect of GCM on efferent striatal and nigro-striatal dopamine neurons. GCM increases activity of the autophagic pathway, as shown by the reduction of autophagic substrate, p-62, and the augmentation of LC3 II, Beclin-1 and LAMP-2 protein levels, direct markers of autophagy, in GCM infused mice. GCM also increases BDNF levels. These results suggest that CGM should be further explored as a putative neuroprotective agent in Huntington's disease. [ABSTRACT FROM AUTHOR]

Cannabinoids are neuroprotective in models of neurodegenerative dementias. Their effects are mostly mediated through CB1 and CB2 receptor-dependent modulation of excitotoxicity, inflammation, oxidative stress, and other processes. We tested the effects of Sativex®, a mixture of Δ9-tetrahydrocannabinol and cannabidiol, acting on both CB1 and CB2 receptors, in parkin-null, human tau overexpressing (PK-/-/TauVLW) mice, a model of complex frontotemporal dementia, parkinsonism, and lower motor neuron disease. The animals received Sativex®, 4.63 mg/kg, ip, daily, for one month, at six months of age, at the onset of the clinical symptoms. We evaluated the effects of Sativex® on behavior, dopamine neurotransmission, glial activation, redox state, mitochondrial activity, and deposition of abnormal proteins. PK-/-/TauVLW mice developed the neurological deficits, but those treated with Sativex® showed less abnormal behaviors related to stress, less auto and hetero-aggression, and less stereotypy. Sativex® significantly reduced the intraneuronal, MAO-related free radicals produced during dopamine metabolism in the limbic system. Sativex® also decreased gliosis in cortex and hippocampus, increased the ratio reduced/oxidized glutathione in the limbic system, reduced the levels of iNOS, and increased those of complex IV in the cerebral cortex. With regard to tau and amyloid pathology, Sativex® reduced the deposition of both in the hippocampus and cerebral cortex of PK-/-/TauVLW mice and increased autophagy. Sativex®, even after a short administration in animals with present behavioral and pathological abnormalities, improves the phenotype, the oxidative stress, and the deposition of proteins in PK-/-/TauVLW mice, a model of complex neurodegenerative disorders. [ABSTRACT FROM AUTHOR]

Dementia occurs often in late stages of Parkinson's disease (PD) but its cause is unknown. Likewise there is little information about the interaction between proteins that produce PD and those implicated in Alzheimer's disease (AD). Here we have investigated the interactions between parkin protein and the amyloid-β (Aβ)1-42 peptide. We examined the effects of oligomeric Aβ1-42 peptide on the survival, differentiation, and signaling pathways in cortical cultures from wild type (WT) and parkin null (PK-KO) mice. We discovered that PK-KO cells were more resistant than WT to Aβ1-42. This peptide induced neuronal cell death, astrogliosis, microglial proliferation, and increased total and hyperphosphorylated tau and levels of chaperones HSP-70 and CHIP in WT, but not in Aβ-treated PK-KO cultures. Aβ1-42 decreased proteasome activities in WT and PK-KO cultures, but the ubiquitination of proteins only increased in WT cultures. Aβ1-42 induced a short activation of ERK1/2 and AKT signaling pathways, implicated in cell survival, in PK-KO-treated cells, and a shift in the autophagy marker LC3-II/LC3-I ratio. In addition, the percentage of cells immunoreactive to both HSC70 and LAMP-2A increased in PK-KO cultures versus WT and furthermore in PK-KO cultures treated with Aβ1-42. Pre-treatment with inhibitors of glutathione synthesis or autophagy reverted the resistance to Aβ1-42 of the PK-KO cultures. In conclusion, the loss of parkin protein triggers the compensatory mechanisms of cell protection against Aβ1-42. Parkin suppression, therefore, is not a risk factor for dementia of AD type. [ABSTRACT FROM AUTHOR]

Dementia occurs often in late stages of Parkinson's disease (PD) but its cause is unknown. Likewise there is little information about the interaction between proteins that produce PD and those implicated in Alzheimer's disease (AD). Here we have investigated the interactions between parkin protein and the amyloid-β (Aβ)1-42 peptide. We examined the effects of oligomeric Aβ1-42 peptide on the survival, differentiation, and signaling pathways in cortical cultures from wild type (WT) and parkin null (PK-KO) mice. We discovered that PK-KO cells were more resistant than WT to Aβ1-42. This peptide induced neuronal cell death, astrogliosis, microglial proliferation, and increased total and hyperphosphorylated tau and levels of chaperones HSP-70 and CHIP in WT, but not in Aβ-treated PK-KO cultures. Aβ1-42 decreased proteasome activities in WT and PK-KO cultures, but the ubiquitination of proteins only increased in WT cultures. Aβ1-42 induced a short activation of ERK1/2 and AKT signaling pathways, implicated in cell survival, in PK-KO-treated cells, and a shift in the autophagy marker LC3-II/LC3-I ratio. In addition, the percentage of cells immunoreactive to both HSC70 and LAMP-2A increased in PK-KO cultures versus WT and furthermore in PK-KO cultures treated with Aβ1-42. Pre-treatment with inhibitors of glutathione synthesis or autophagy reverted the resistance to Aβ1-42 of the PK-KO cultures. In conclusion, the loss of parkin protein triggers the compensatory mechanisms of cell protection against Aβ1-42. Parkin suppression, therefore, is not a risk factor for dementia of AD type. [ABSTRACT FROM AUTHOR]

Recent clinical studies have suggested that there is an increased risk of Alzheimer's disease (AD) in patients undergoing surgical interventions, but it is unknown whether this effect is related to anesthesia, cardiovascular complications of surgery, or associated conditions such as hypothermia. In addition, many patients, especially the elderly, present persistent post-operative cognitive deterioration after anesthesia, without clear complications during surgery. Experimental studies in animals may be helpful to dissect the pathogenic role of the different factors involved in surgery. Here, we review studies on the effects of anesthesia on neuronal function performed in tissue culture and in experimental animals. Several studies have shown that a small inhalation of anesthetics induces activation of caspases and cell toxicity on glioma and pheochromocitoma cells in culture, which is prevented by treatment with the metal chelating agent clioquinol. Exposure of old rodents to anesthesia produced memory deficits and increased levels of amyloid-β (Aβ) peptide and phosphorylated tau in brain. The effects of long term or short term repetitive exposure to small molecular weight anesthetics are more severe in transgenic AβPPswe than in wild type mice. In the former, low molecular weight increased the number of TUNEL+ apoptotic cells and the ratio of pro-apoptotic proteins in hippocampus; reduced astroglial and increased microglial responses; increased Aβ aggregates and high molecular weight peptides; abnormal chaperone responses and reduced autophagy. In conclusion, anesthetic gases induce changes which may reproduce AD pathology in mice with mutations which produced AD. It would be interesting to know whether anesthetics are risky for subjects with special genetic risk factors. [ABSTRACT FROM AUTHOR]

There is a great interest in the environmental and genetic factors which modify the risk of Alzheimer's disease since the manipulation of these factors could help to change the prevalence and natural course of this disease. Among the first group, anesthesia and surgery have been considered as risk enhancers, based mostly on "in vitro" experiments and epidemiological studies. We have investigated the effects of repetitive anesthesia, twice a week, for 3 months, from 7 to 10 months of age, with isoflurane on survival, behavior, apoptosis in hippocampal cells, amyloid-β (Aβ) peptide and tau patterns, chaperones and autophagy in WT and AβPP{swe} mice. We have found that AβPP{swe} mice treated with isoflurane have increased mortality, less responsiveness after anesthesia, long lasting reduced exploratory behavior, increased number of TUNEL{+} apoptotic cells, and increased ratio of pro-apoptotic proteins in hippocampus, reduced astroglial and increased microglial responses, increased Aβ aggregates and high molecular weight peptides, abnormal chaperone responses and reduced autophagy. These effects were not present in WT mice, suggesting that the deleterious impact of isoflurane on behavior, survival, neuronal cell death, and processing of proteins involved in neurodegeneration is restricted to subjects with increased susceptibility but does not affect normal subjects. [ABSTRACT FROM AUTHOR]

Parkin mutations in humans produce parkinsonism whose pathogenesis is related to impaired protein degradation, increased free radicals and abnormal neurotransmitter release. In this study, we have investigated whether partial proteasomal inhibition by epoxomicin, an ubiquitin proteasomal system (UPS) irreversible inhibitor, further aggravates the cellular effects of parkin suppression in midbrain neurons and glia. We observed that parkin null (PK-KO) midbrain neuronal cultures are resistant to epoxomicin-induced cell death. This resistance is due to increased GSH and DJ-1 protein levels in PK-KO mice. The treatment with epoxomicin increases, in wild type (WT) cultures, the pro-apoptotic Bax/Bcl-2 ratio, the phosphorylation of tau, and the levels of chaperones heat-shock protein 70 and C-terminal Hsc-interacting protein, but none of these effects took place in epoxomicin-treated PK-KO cultures. Poly-ubiquitinated proteins increased more in WT than in PK-KO-treated neuronal cultures. Parkin accumulated in WT neuronal cultures treated with epoxomicin. Markers of autophagy, such as LC3II/I, were increased in naïve PK-KO cultures, and further increased after treatment with epoxomicin, implying that the blockade of the proteasome in PK-KO neurons triggers the enhancement of autophagy. The treatment withl-buthionine- S, R-sulfoximine and the inhibition of autophagy, however, reverted the increase resistance to epoxomicin of the PK-KO cultures. We also found that PK-KO glial cells, stressed by growth in defined medium and depleted of GSH, were more susceptible to epoxomicin induced cell death than WT glia treated similarly. This susceptibility was linked to reduced GSH levels and less heat-shock protein 70 response, and to activation of p-serine/threonine kinase protein signaling pathway as well as to increased poly-ubiquitinated proteins. These data suggest that mild UPS inhibition is compensated by other mechanisms in PK-KO midbrain neurons. However the depletion of GSH, as happens in stressed glia, suppresses the protection against UPS inhibition-induced cell death. Furthermore, GSH inhibition regulated differentially UPS activity and in old PK-KO mice, which have depletion of GSH, UPS activity is decreased in comparison with that of old-WT. [ABSTRACT FROM AUTHOR]

Estrogens are considered neurotrophic for dopamine neurons. Parkinson’s disease is more frequent in males than in females, and more prevalent in females with short reproductive life. Estrogens are neuroprotective against neurotoxic agents for dopamine neurons in vivo and in vitro. Here, we have investigated the role of estrogens in wild-type (WT) and parkin null mice (PK−/−). WT mice present sexual dimorphisms in neuroprotective mechanisms (Bcl-2/Bax, chaperones, and GSH), but some of these inter-sex differences disappear in PK−/−. Tyrosine hydroxylase (TH) protein and TH+ cells decreased earlier and more severely in female than in male PK−/− mice. Neuronal cultures from midbrain of WT and PK−/− mice were treated with estradiol from 10 min to 48 h. Short-term treatments activated the mitogen-activated protein kinase pathway of WT and PK−/− neurons and the phosphatidylinositol 3′-kinase/AKT/glycogen synthase kinase-3 pathway of WT but not of PK−/− cultures. Long-term treatments with estradiol increased the number of TH+ neurons, the TH expression, and the extension of neurites, and decreased the level of apoptosis, the expression of glial fibrillary acidic protein, and the number of microglial cells in WT but not in PK−/− cultures. The levels of estrogen receptor-α were elevated in midbrain cultures and in the striatum of adult PK−/− male mice, suggesting that suppression of parkin changes the estrogen receptor-α turnover. From our data, it appears that parkin participates in the cellular estrogen response which could be of interest in the management of parkin-related Parkinson’s disease patients. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is a progressive degenerative disorder and the most common cause of dementia in aging populations. Although the pathological hallmarks of AD are well defined, currently no effective therapy exists. Liver growth factor (LGF) is a hepatic albumin–bilirubin complex with activity as a tissue regenerating factor in several neurodegenerative disorders such as Parkinson's disease and Friedreich's ataxia. Our aim here was to analyze the potential therapeutic effect of LGF on the APPswe mouse model of AD. Twenty-month-old mice received intraperitoneal (i.p.) injections of 1.6 µg LGF or saline, twice a week during three weeks. Mice were sacrificed one week later, and the hippocampus and dorsal cortex were prepared for immunohistochemical and biochemical studies. LGF treatment reduced amyloid-β (Aβ) content, phospho-Tau/Tau ratio and the number of Aβ plaques with diameter larger than 25 µm. LGF administration also modulated protein ubiquitination and HSP70 protein levels, reduced glial reactivity and inflammation, and the expression of the pro-apoptotic protein Bax. Because the administration of this factor also restored cognitive damage in APPswe mice, we propose LGF as a novel therapeutic tool that may be useful for the treatment of AD. [ABSTRACT FROM AUTHOR]

A response by the authors to a commentary about their study "Anesthesia with isoflurane increases amyloid pathology in mice models of Alzheimer's disease," published within the issue is presented. They reportedly agree that additional studies is needed to explore the role of anesthesia in the pathogenesis of Alzheimer's disease. They further pointed out that two key issues should be taken in consideration in interpreting their laboratory findings. Additionally, the authors argue that their article is significant from a clinical point of view.