Elevated cholesterol in ATAD3 mutants is a compensatory mechanism that leads to membrane cholesterol aggregation.

Aberrant cholesterol metabolism causes neurological disease and neurodegeneration, and mitochondria have been linked to perturbed cholesterol homeostasis via the study of pathological mutations in the ATAD3 gene cluster. However, whether the cholesterol changes were compensatory or contributory to the disorder was unclear, and the effects on cell membranes and the wider cell were also unknown. Using patient-derived cells, we show that cholesterol perturbation is a conserved feature of pathological ATAD3 variants that is accompanied by an expanded lysosome population containing membrane whorls characteristic of lysosomal storage diseases. Lysosomes are also more numerous in Drosophila neural progenitor cells expressing mutant Atad3, which exhibit abundant membrane-bound cholesterol aggregates, many of which co-localize with lysosomes. By subjecting the Drosophila Atad3 mutant to nutrient restriction and cholesterol supplementation, we show that the mutant displays heightened cholesterol dependence. Collectively, these findings suggest that elevated cholesterol enhances tolerance to pathological ATAD3 variants; however, this comes at the cost of inducing cholesterol aggregation in membranes, which lysosomal clearance only partly mitigates.

Dysregulated FOXO1 activity drives skeletal muscle intrinsic dysfunction in amyotrophic lateral sclerosis.

Amyotrophic Lateral Sclerosis (ALS) is a multisystemic neurodegenerative disorder, with accumulating evidence indicating metabolic disruptions in the skeletal muscle preceding disease symptoms, rather than them manifesting as a secondary consequence of motor neuron (MN) degeneration. Hence, energy homeostasis is deeply implicated in the complex physiopathology of ALS and skeletal muscle has emerged as a key therapeutic target. Here, we describe intrinsic abnormalities in ALS skeletal muscle, both in patient-derived muscle cells and in muscle cell lines with genetic knockdown of genes related to familial ALS, such as TARDBP (TDP-43) and FUS. We found a functional impairment of myogenesis that parallels defects of glucose oxidation in ALS muscle cells. We identified FOXO1 transcription factor as a key mediator of these metabolic and functional features in ALS muscle, via gene expression profiling and biochemical surveys in TDP-43 and FUS-silenced muscle progenitors. Strikingly, inhibition of FOXO1 mitigated the impaired myogenesis in both the genetically modified and the primary ALS myoblasts. In addition, specific in vivo conditional knockdown of TDP-43 or FUS orthologs (TBPH or caz) in Drosophila muscle precursor cells resulted in decreased innervation and profound dysfunction of motor nerve terminals and neuromuscular synapses, accompanied by motor abnormalities and reduced lifespan. Remarkably, these phenotypes were partially corrected by foxo inhibition, bolstering the potential pharmacological management of muscle intrinsic abnormalities associated with ALS. The findings demonstrate an intrinsic muscle dysfunction in ALS, which can be modulated by targeting FOXO factors, paving the way for novel therapeutic approaches that focus on the skeletal muscle as complementary target tissue.

Genetic Inactivation of Free Fatty Acid Receptor 3 Impedes Behavioral Deficits and Pathological Hallmarks in the APPswe Alzheimer's Disease Mouse Model.

The free fatty acid FFA3 receptor (FFA3R) belongs to the superfamily of G-protein-coupled receptors (GPCRs). In the intestine and adipose tissue, it is involved in the regulation of energy metabolism, but its function in the brain is unknown. We aimed, first, to investigate the expression of the receptor in the hippocampus of Alzheimer disease (AD) patients at different stages of the disease and, second, to assess whether genetic inactivation of the Ffar3 gene could affect the phenotypic features of the APPswe mouse model. The expression of transcripts for FFA receptors in postmortem human hippocampal samples and in the hippocampus of wild-type and transgenic mice was analyzed by RT-qPCR. We generated a double transgenic mouse, FFA3R-/-/APPswe, to perform cognition studies and to assess, by immunoblotting Aß and tau pathologies and the differential expression of synaptic plasticity-related proteins. For the first time, the occurrence of the FFA3R in the human hippocampus and its overexpression, even in the first stages of AD, was demonstrated. Remarkably, FFA3R-/-/APPswe mice do not have the characteristic memory impairment of 12-month-old APPswe mice. Additionally, this newly generated transgenic line does not develop the most important Alzheimer's disease (AD)-related features, such as amyloid beta (Aß) brain accumulations and tau hyperphosphorylation. These findings are accompanied by increased levels of the insulin-degrading enzyme (IDE) and lower activity of the tau kinases GSK3ß and Cdk5. We conclude that the brain FFA3R is involved in cognitive processes and that its inactivation prevents AD-like cognitive decline and pathological hallmarks.

Modulation of BDNF cleavage by plasminogen-activator inhibitor-1 contributes to Alzheimer's neuropathology and cognitive deficits.

Brain-derived neurotrophic factor (BDNF) plays pivotal roles in neuronal function. The cleaved - mature - form of BDNF (mBDNF), predominantly expressed in adult brains, critically determines its effects. However, insufficient proteolytic processing under pathology may lead to the precursor form of BDNF (proBDNF) and thereby increased neuronal apoptosis and synaptic weakening. Previous findings in our lab showed that cognitive stimulation (CS) delayed memory decline in Tg2576 mouse model of Alzheimer's disease (AD), an effect that was tightly associated with augmented levels of mBDNF. In view of this association, the present study explored whether altered cleavage of BDNF could be involved in AD-related traits triggered by excessive amyloid-ß (Aß) pathology and whether this process could be therapeutically targeted. Aß pathology, both in AD patient samples and experimental models, triggered the upregulation of plasminogen-activator inhibitor-1 (PAI-1) via JNK/c-Jun. This led to inhibition of plasmin-regulated conversion of mBDNF. Pharmacological inhibition of PAI-1 with PAI-039 sufficiently reverted Aß-induced tau hyperphosphorylation and neurotoxicity. Chronic treatment of 15 old-month Tg2576 mice with oral administration of PAI-039 resulted in improved BDNF maturation and cognitive function without inducing significant changes in amyloid burden. In conclusion, upregulation of PAI-1 may be a critical mechanism underlying insufficient neurotrophic support and increased neurodegeneration associated with AD. Thus, targeting BDNF maturation through pharmacological inhibition of PAI-1 might become a potential treatment for AD.

Insights into the mechanisms of copper dyshomeostasis in amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a severe neuromuscular disease characterised by a progressive loss of motor neurons that usually results in paralysis and death within 2 to 5 years after disease onset. The pathophysiological mechanisms involved in ALS remain largely unknown and to date there is no effective treatment for this disease. Here, we review clinical and experimental evidence suggesting that dysregulation of copper homeostasis in the central nervous system is a crucial underlying event in motor neuron degeneration and ALS pathophysiology. We also review and discuss novel approaches seeking to target copper delivery to treat ALS. These novel approaches may be clinically relevant not only for ALS but also for other neurological disorders with abnormal copper homeostasis, such as Parkinson's, Huntington's and Prion diseases.

Down-regulation of glutamatergic terminals (VGLUT1) driven by Aß in Alzheimer's disease.

Alzheimer's disease (AD) is characterized phenotypically by memory impairment, histologically by accumulation of pTau and ß-amyloid peptide and morphologically by a loss of nerve terminals in cortical and hippocampal regions. As glutamate is the principle excitatory neurotransmitter of the central nervous system (CNS), the glutamatergic system may play an important role in AD. To date, not many studies have addressed the deleterious effects of Aß on glutamatergic terminals; therefore the aim of this study was to investigate how Aß affects glutamatergic terminals and to assess the extent to which alterations in the glutamatergic neurotransmission could impact susceptibility to the illness. The present study shows that Aß caused a loss of glutamatergic terminals, measured by VGLUT1 protein levels, in Tg2576 primary cell cultures, Tg2576 mice and AD patient brains, and also when Aß was added exogenously to hippocampal cell cultures. Interestingly, no correlation was found between cognition and decreased VGLUT1 levels. Moreover, when Aß1-42 was intracerebroventricularlly administered into VGLUT1+/- mice, altered synaptic plasticity and increased neuroinflammation was observed in the hippocampus of those animals. In conclusion, the present study not only revealed susceptibility of glutamatergic nerve terminals to Aß induced toxicity but also underlined the importance of VGLUT1 in the progression of AD, as the decrease of this protein levels could increase the susceptibility to subsequent deleterious inputs by exacerbating Aß induced neuroinflammation and synaptic plasticity disruption. © 2016 Wiley Periodicals, Inc.

Decreased levels of guanosine 3', 5'-monophosphate (cGMP) in cerebrospinal fluid (CSF) are associated with cognitive decline and amyloid pathology in Alzheimer's disease.

AIMS: Levels of the cyclic nucleotides guanosine 3', 5'-monophosphate (cGMP) or adenosine 3', 5'-monophosphate (cAMP) that play important roles in memory processes are not characterized in Alzheimer's disease (AD). The aim of this study was to analyse the levels of these nucleotides in cerebrospinal fluid (CSF) samples from patients diagnosed with clinical and prodromal stages of AD and study the expression level of the enzymes that hydrolyzed them [phosphodiesterases (PDEs)] in the brain of AD patients vs. METHODS: For cGMP and cAMP CSF analysis, the cohort (n = 79) included cognitively normal participants (subjective cognitive impairment), individuals with stable mild cognitive impairment or AD converters (sMCI and cMCI), and mild AD patients. A high throughput liquid chromatography-tandem mass spectrometry method was used. Interactions between CSF cGMP or cAMP with mini-mental state examination (MMSE) score, CSF Aß(1-42) and CSF p-tau were analysed. For PDE4, 5, 9 and 10 expression analysis, brains of AD patients vs. controls (n = 7 and n = 8) were used. RESULTS: cGMP, and not cAMP levels, were significantly lower in the CSF of patients diagnosed with mild AD when compared with nondemented controls. CSF levels of cGMP showed a significant association with MMSE-diagnosed clinical dementia and with CSF biomarker Aß42 in AD patients. Significant increase in PDE5 expression was detected in temporal cortex of AD patients compared with that of age-matched healthy control subjects. No changes in the expression of others PDEs were detected. CONCLUSIONS: These results support the potential involvement of cGMP in the pathological and clinical development of AD. The cGMP reduction in early stages of AD might participate in the aggravation of amyloid pathology and cognitive decline.

Early cognitive stimulation compensates for memory and pathological changes in Tg2576 mice.

Education and cognitive occupations are commonly associated to reduce risk of Alzheimer's disease (AD) or dementia. Animal studies have demonstrated that cognitive stimulation (CS) achieved by social/physical activities and/or enriched environments compensates for memory decline. We have elaborated a novel paradigm of CS that is devoid of physical/social activity and enriched environments. 4 month-old Tg2576 mice were cognitively trained for 8 weeks and, after a break of 8 months, long-lasting effects of CS on cognitive abilities and AD-like pathology were measured. Morris Water Maze (MWM) and Novel Object Recognition (NOR) tests showed that deficits in spatial and recognition memories were compensated by CS. These outcomes were accompanied by increased levels of hippocampal post-synaptic markers (PSD95 and NR1) and proteins involved in synaptic formation (Arc, ß-catenin). CS softened amyloid pathology in terms of reduced levels of Aß1-42 and the dodecameric assembly, referred as Aß*56. CS appeared to affect the APP processing since differences in levels of ADAM17, BACE1 and C99/C83 ratio were found. Tau hyper-phosphorylation and high activities of tau kinases were also reduced by CS. In contrast, CS did not induce any of these molecular changes in wild-type mice. The present findings suggest beneficial and long-lasting effects of CS early in life on cognitive decline and AD-like pathology.

A mammalian-specific Alex3/Gαq protein complex regulates mitochondrial trafficking, dendritic complexity, and neuronal survival.

Mitochondrial dynamics and trafficking are essential to provide the energy required for neurotransmission and neural activity. We investigated how G protein-coupled receptors (GPCRs) and G proteins control mitochondrial dynamics and trafficking. The activation of Gαq inhibited mitochondrial trafficking in neurons through a mechanism that was independent of the canonical downstream PLCß pathway. Mitoproteome analysis revealed that Gαq interacted with the Eutherian-specific mitochondrial protein armadillo repeat-containing X-linked protein 3 (Alex3) and the Miro1/Trak2 complex, which acts as an adaptor for motor proteins involved in mitochondrial trafficking along dendrites and axons. By generating a CNS-specific Alex3 knockout mouse line, we demonstrated that Alex3 was required for the effects of Gαq on mitochondrial trafficking and dendritic growth in neurons. Alex3-deficient mice had altered amounts of ER stress response proteins, increased neuronal death, motor neuron loss, and severe motor deficits. These data revealed a mammalian-specific Alex3/Gαq mitochondrial complex, which enables control of mitochondrial trafficking and neuronal death by GPCRs.

Side chain-oxidized oxysterols regulate the brain renin-angiotensin system through a liver X receptor-dependent mechanism.

Disturbances in cholesterol metabolism have been associated with hypertension and neurodegenerative disorders. Because cholesterol metabolism in the brain is efficiently separated from plasma cholesterol by the blood-brain barrier (BBB), it is an unsolved paradox how high blood cholesterol can cause an effect in the brain. Here, we discuss the possibility that cholesterol metabolites permeable to the BBB might account for these effects. We show that 27-hydroxycholesterol (27-OH) and 24S-hydroxycholesterol (24S-OH) up-regulate the renin-angiotensin system (RAS) in the brain. Brains of mice on a cholesterol-enriched diet showed up-regulated angiotensin converting enzyme (ACE), angiotensinogen (AGT), and increased JAK/STAT activity. These effects were confirmed in in vitro studies with primary neurons and astrocytes exposed to 27-OH or 24S-OH, and were partially mediated by liver X receptors. In contrast, brain RAS activity was decreased in Cyp27a1-deficient mice, a model exhibiting reduced 27-OH production from cholesterol. Moreover, in humans, normocholesterolemic patients with elevated 27-OH levels, due to a CYP7B1 mutation, had markers of activated RAS in their cerebrospinal fluid. Our results demonstrate that side chain-oxidized oxysterols are modulators of brain RAS. Considering that levels of cholesterol and 27-OH correlate in the circulation and 27-OH can pass the BBB into the brain, we suggest that this cholesterol metabolite could be a link between high plasma cholesterol levels, hypertension, and neurodegeneration.

Cholinergic denervation exacerbates amyloid pathology and induces hippocampal atrophy in Tg2576 mice.

The main pathological hallmarks of Alzheimer's disease (AD) consist of amyloid plaques and neurofibrillary tangles. Hippocampal cell loss, atrophy and cholinergic dysfunction are also features of AD. The present work is aimed at studying the interactions between cholinergic denervation, APP processing and hippocampal integrity. The cholinergic immunotoxin mu p-75-saporin was injected into the 3rd ventricle of 6- to 8-month-old Tg2576 mice to induce a cholinergic denervation. Four weeks after cholinergic immunolesion, a significant 14-fold increase of soluble Aß1-42 was observed. Cholinergically lesioned Tg2576 mice showed hippocampal atrophy together with degenerating FluoroJade-B-stained neurons and reduction of synaptophysin expression in CA1-3 pyramidal layers. We also found that cholinergic denervation led to reduced levels of ADAM17 in hippocampus of Tg2576 mice. Inhibition of ADAM17 with TAPI-2 (5 µM) decreased viability of hippocampal primary neurons from Tg2576 brains and decreased phosphorylation of downstream effectors of trophic signalling (ERK and Akt). The cholinergic agonist carbachol (100 µM) rescued these effects, suggesting that cholinergic deficits might render hippocampus more vulnerable to neurotoxicity upon certain toxic environments. The present work proposes a novel model of AD that worsens the patent amyloid pathology of Tg2576 mice together with hippocampal synaptic pathology and neurodegeneration. Drugs aimed at favoring cholinergic transmission should still be considered as potential treatments of AD.

Defects of Nutrient Signaling and Autophagy in Neurodegeneration.

Neurons are post-mitotic cells that allocate huge amounts of energy to the synthesis of new organelles and molecules, neurotransmission and to the maintenance of redox homeostasis. In neurons, autophagy is not only crucial to ensure organelle renewal but it is also essential to balance nutritional needs through the mobilization of internal energy stores. A delicate crosstalk between the pathways that sense nutritional status of the cell and the autophagic processes to recycle organelles and macronutrients is fundamental to guarantee the proper functioning of the neuron in times of energy scarcity. This review provides a detailed overview of the pathways and processes involved in the balance of cellular energy mediated by autophagy, which when defective, precipitate the neurodegenerative cascade of Parkinson's disease, frontotemporal dementia, amyotrophic lateral sclerosis or Alzheimer's disease.

Cholinergic hypofunction impairs memory acquisition possibly through hippocampal Arc and BDNF downregulation.

Recent evidence suggests that activity-regulated cytoskeleton associated protein (Arc) and brain-derived neurotrophic factor (BDNF) are key players in the cellular mechanisms that trigger synaptic changes and memory consolidation. Cholinergic deafferentiation of hippocampus has been largely shown to induce memory impairments in different behavioral tasks. However, the mechanisms underlying cholinergic-induced memory formation remain unclear. The role of hippocampal cholinergic denervation on synaptic consolidation and further acquisition of spatial memory was hereby examined by analyzing Arc and BDNF in standard environment and after behavioral training in Morris water maze (MWM). In standard environment, a cholinergic hypofunction induced by the toxin (192) IgG-saporin led to significant decreases in Arc protein and mRNA as well as in BDNF. Lesioned rats subjected to MWM showed a worse acquisition performance that was reversed after galantamine treatment. Recovery of memory acquisition was accompanied by normalization of Arc and BDNF levels in hippocampus. Stimulation of muscarinic, but not nicotinic receptors, in hippocampal primary neurons caused a rapid induction of Arc production. These data suggest that cholinergic denervation of hippocampus leads to deficits in muscarinic-dependent induction of Arc and a subsequent impairment of spatial memory acquisition.

Analysis of chiral amino acids in cerebrospinal fluid samples linked to different stages of Alzheimer disease.

Chiral micellar electrokinetic chromatography with laser-induced fluorescence detection (chiral-MEKC-LIF) was used to investigate D- and L-amino acid contents in cerebrospinal fluid (CSF) samples related to different Alzheimer disease (AD) stages. CSF samples were taken from (i) control subjects (S1 pool), (ii) subjects showing a mild cognitive impairment who remained stable (S2 pool), (iii) subjects showing an mild cognitive impairment that progressed to AD (S3 pool) and (iv) subjects diagnosed with AD (S4 pool). The optimized procedure only needed 10 µL of CSF and it included sample cleaning, derivatization with FITC and chiral-MEKC-LIF separation. Eighteen standard amino acids were baseline separated with efficiencies up to 703,000 plates/m, high sensitivity (LODs in the nM range) and good resolution (values ranging from 2.6 to 9.5). Using this method, L-Arg, L-Leu, L-Gln, γ-aminobutyric acid, L-Ser, D-Ser, L-Ala, Gly, L-Lys, L-Glu and L-Asp were detected in all the CSF samples. S3 and S4 samples (i.e. AD subjects) showed significant lower amounts of L-Arg L-Lys, L-Glu and L-Asp compared to the non-AD S1 and S2 samples, showing in the S4 group the lowest amounts of L-Arg L-Lys, L-Glu and L-Asp. Moreover, γ-aminobutyric acid was significantly higher in AD subjects with the highest amount also found for S4. No significant differences were observed for the rest of amino acids including D-Ser. Based on the obtained chiral-MEKC-LIF data, it was possible to correctly classify all the samples into the four groups. These results demonstrate that the use of enantioselective procedures as the one developed in this work can provide some new light on the investigations of AD, including the discovery of new biomarkers related to different stages of AD.

Amyotrophic lateral sclerosis (ALS), cancer, autoimmunity and metabolic disorders: An unsolved tantalizing challenge.

Amyotrophic lateral sclerosis (ALS) commonly referred to as motor neurone disease, is a neurodegenerative disease of unknown pathogenesis that progresses rapidly and has attracted an increased amount of scholarly interest in recent years. The current conception of amyotrophic lateral sclerosis has transitioned into a more complex theory in which individual genetic risk, ageing and environmental factors interact, leading to disease onset in subjects in whom the sum of these factors reach a determined threshold. Based on this conceptualization, the environmental conditions, particularly those that are potentially modifiable, are becoming increasingly relevant. In this review, the current integrative model of the disease is discussed. In addition, we explore the role of cancer, autoimmunity and metabolic diseases as examples of novel, non-genetic and environmental factors. Together with the potential triggers or perpetuating pathogenic mechanisms along with new insights into potential lines of future research are provided. LINKED ARTICLES: This article is part of a themed issue on Neurochemistry in Japan. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.6/issuetoc.

Corticosteroid-binding-globulin (CBG)-deficient mice show high pY216-GSK3ß and phosphorylated-Tau levels in the hippocampus.

Corticosteroid-binding globulin (CBG) is the specific carrier of circulating glucocorticoids, but evidence suggests that it also plays an active role in modulating tissue glucocorticoid activity. CBG polymorphisms affecting its expression or affinity for glucocorticoids are associated with chronic pain, chronic fatigue, headaches, depression, hypotension, and obesity with an altered hypothalamic pituitary adrenal axis. CBG has been localized in hippocampus of humans and rodents, a brain area where glucocorticoids have an important regulatory role. However, the specific CBG function in the hippocampus is yet to be established. The aim of this study was to investigate the effect of the absence of CBG on hippocampal glucocorticoid levels and determine whether pathways regulated by glucocorticoids would be altered. We used cbg-/- mice, which display low total-corticosterone and high free-corticosterone blood levels at the nadir of corticosterone secretion (morning) and at rest to evaluate the hippocampus for total- and free-corticosterone levels; 11ß-hydroxysteroid dehydrogenase expression and activity; the expression of key proteins involved in glucocorticoid activity and insulin signaling; microtubule-associated protein tau phosphorylation, and neuronal and synaptic function markers. Our results revealed that at the nadir of corticosterone secretion in the resting state the cbg-/- mouse hippocampus exhibited slightly elevated levels of free-corticosterone, diminished FK506 binding protein 5 expression, increased corticosterone downstream effectors and altered MAPK and PI3K pathway with increased pY216-GSK3ß and phosphorylated tau. Taken together, these results indicate that CBG deficiency triggers metabolic imbalance which could lead to damage and long-term neurological pathologies.

The Skeletal Muscle Emerges as a New Disease Target in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that leads to progressive degeneration of motor neurons (MNs) and severe muscle atrophy without effective treatment. Most research on ALS has been focused on the study of MNs and supporting cells of the central nervous system. Strikingly, the recent observations of pathological changes in muscle occurring before disease onset and independent from MN degeneration have bolstered the interest for the study of muscle tissue as a potential target for delivery of therapies for ALS. Skeletal muscle has just been described as a tissue with an important secretory function that is toxic to MNs in the context of ALS. Moreover, a fine-tuning balance between biosynthetic and atrophic pathways is necessary to induce myogenesis for muscle tissue repair. Compromising this response due to primary metabolic abnormalities in the muscle could trigger defective muscle regeneration and neuromuscular junction restoration, with deleterious consequences for MNs and thereby hastening the development of ALS. However, it remains puzzling how backward signaling from the muscle could impinge on MN death. This review provides a comprehensive analysis on the current state-of-the-art of the role of the skeletal muscle in ALS, highlighting its contribution to the neurodegeneration in ALS through backward-signaling processes as a newly uncovered mechanism for a peripheral etiopathogenesis of the disease.

A multicentre validation study of the diagnostic value of plasma neurofilament light.

Increased cerebrospinal fluid neurofilament light (NfL) is a recognized biomarker for neurodegeneration that can also be assessed in blood. Here, we investigate plasma NfL as a marker of neurodegeneration in 13 neurodegenerative disorders, Down syndrome, depression and cognitively unimpaired controls from two multicenter cohorts: King's College London (n = 805) and the Swedish BioFINDER study (n = 1,464). Plasma NfL was significantly increased in all cortical neurodegenerative disorders, amyotrophic lateral sclerosis and atypical parkinsonian disorders. We demonstrate that plasma NfL is clinically useful in identifying atypical parkinsonian disorders in patients with parkinsonism, dementia in individuals with Down syndrome, dementia among psychiatric disorders, and frontotemporal dementia in patients with cognitive impairment. Data-driven cut-offs highlighted the fundamental importance of age-related clinical cut-offs for disorders with a younger age of onset. Finally, plasma NfL performs best when applied to indicate no underlying neurodegeneration, with low false positives, in all age-related cut-offs.

ALS-derived fibroblasts exhibit reduced proliferation rate, cytoplasmic TDP-43 aggregation and a higher susceptibility to DNA damage.

BACKGROUND: Dermic fibroblasts have been proposed as a potential genetic-ALS cellular model. This study aimed to explore whether dermic fibroblasts from patients with sporadic-ALS (sALS) recapitulate alterations typical of ALS motor neurons and exhibit abnormal DNA-damage response. METHODS: Dermic fibroblasts were obtained from eight sALS patients and four control subjects. Cellular characterization included proliferation rate analysis, cytoarchitecture studies and confocal immunofluorescence assessment for TDP-43. Additionally, basal and irradiation-induced DNA damage was evaluated by confocal immunofluorescence and biochemical techniques. RESULTS: sALS-fibroblasts showed decreased proliferation rates compared to controls. Additionally, whereas control fibroblasts exhibited the expected normal spindle-shaped morphology, ALS fibroblasts were thinner, with reduced cell size and enlarged nucleoli, with frequent cytoplasmic TDP-43aggregates. Also, baseline signs of DNA damage were evidenced more frequently in ALS-derived fibroblasts (11 versus 4% in control-fibroblasts). Assays for evaluating the irradiation-induced DNA damage demonstrated that DNA repair was defective in ALS-fibroblasts, accumulating more than double of γH2AX-positive DNA damage foci than controls. Very intriguingly, the proportion of fibroblasts particularly vulnerable to irradiation (with more than 15 DNA damage foci per nucleus) was seven times higher in ALS-derived fibroblasts than in controls. CONCLUSIONS: Dermic-derived ALS fibroblasts recapitulate relevant cellular features of sALS and show a higher susceptibility to DNA damage and defective DNA repair responses. Altogether, these results support that dermic fibroblasts may represent a convenient and accessible ALS cellular model to study pathogenetic mechanisms, particularly those related to DNA damage response, as well as the eventual response to disease-modifying therapies.

A comprehensive serum lipidome profiling of amyotrophic lateral sclerosis.

Objective: To perform a comprehensive lipid profiling to evaluate potential lipid metabolic differences between patients with amyotrophic lateral sclerosis (ALS) and controls, and to provide a more profound understanding of the metabolic abnormalities in ALS. Methods: Twenty patients with ALS and 20 healthy controls were enrolled in a cross-sectional study. Untargeted lipidomics profiling in fasting serum samples were performed by optimized UPLC-MS platforms for broad lipidome coverage. Datasets were analyzed by univariate and a variety of multivariate procedures. Results: We provide the most comprehensive blood lipid profiling of ALS to date, with a total of 416 lipids measured. Univariate analysis showed that 28 individual lipid features and two lipid classes, triacylglycerides and oxidized fatty acids (FAs), were altered in patients with ALS, although none of these changes remained significant after multiple comparison adjustment. Most of these changes remained constant after removing from the analysis individuals treated with lipid-lowering drugs. The non-supervised principal component analysis did not identify any lipid clustering of patients with ALS and controls. Despite this, we performed a variety of linear and non-linear supervised multivariate models to select the most reliable features that discriminate the lipid profile of patients with ALS from controls. These were the monounsaturated FAs C24:1n-9 and C14:1, the triglyceride TG(51:4) and the sphingomyelin SM(36:2). Conclusions: Peripheral alterations of lipid metabolism are poorly defined in ALS, triacylglycerides and certain types of FAs could contribute to the different lipid profile of patients with ALS. These findings should be validated in an independent cohort.