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ObjectiveA hallmark of amyotrophic lateral sclerosis (ALS) caused by mutations in superoxide dismutase-1 (SOD1) are inclusions containing SOD1 in motor neurons. Here, we searched for SOD1-positive inclusions in 29 patients carrying ALS-linked mutations in six other genes.MethodsA panel of antibodies that specifically recognise misfolded SOD1 species were used for immunohistochemical investigations of autopsy tissue.ResultsThe 18 patients with hexanucleotide-repeat-expansions in C9orf72 had inclusions of misfolded wild type (WT) SOD1WT in spinal motor neurons. Similar inclusions were occasionally observed in medulla oblongata and in the motor cortex and frontal lobe. Patients with mutations in FUS, KIF5A, NEK1, ALSIN or VAPB, carried similar SOD1WT inclusions. Minute amounts of misSOD1WT inclusions were detected in 2 of 20 patients deceased from non-neurological causes and in 4 of 10 patients with other neurodegenerative diseases. Comparison was made with 17 patients with 9 different SOD1 mutations. Morphologically, the inclusions in patients with mutations in C9orf72HRE, FUS, KIF5A, NEK1, VAPB and ALSIN resembled inclusions in patients carrying the wildtype-like SOD1D90A mutation, whereas patients carrying unstable SOD1 mutations (A4V, V5M, D76Y, D83G, D101G, G114A, G127X, L144F) had larger skein-like SOD1-positive inclusions.Conclusions and relevanceAbundant inclusions containing misfolded SOD1WT are found in spinal and cortical motor neurons in patients carrying mutations in six ALS-causing genes other than SOD1. This suggests that misfolding of SOD1WT can be part of a common downstream event that may be pathogenic. The new anti-SOD1 therapeutics in development may have applications for a broader range of patients.

Pathogenic variants in SOD1, encoding superoxide dismutase 1, are responsible for about 20% of all familial amyotrophic lateral sclerosis cases, through a gain-of-function mechanism. Recently, two reports showed that a specific homozygous SOD1 loss-of-function variant is associated with an infantile progressive motor-neurological syndrome. Exome sequencing followed by molecular studies, including cDNA analysis, SOD1 protein levels and enzymatic activity, and plasma neurofilament light chain levels, were undertaken in an infant with severe global developmental delay, axial hypotonia and limb spasticity. We identified a homozygous 3-bp in-frame deletion in SOD1. cDNA analysis predicted the loss of a single valine residue from a tandem pair (p.Val119/Val120) in the wild-type protein, yet expression levels and splicing were preserved. Analysis of SOD1 activity and protein levels in erythrocyte lysates showed essentially no enzymatic activity and undetectable SOD1 protein in the child, whereas the parents had ∼50% protein expression and activity relative to controls. Neurofilament light chain levels in plasma were elevated, implying ongoing axonal injury and neurodegeneration. Thus, we provide confirmatory evidence of a second biallelic variant in an infant with a severe neurological syndrome and suggest that the in-frame deletion causes instability and subsequent degeneration of SOD1. We highlight the importance of the valine residues at positions V119-120, and suggest possible implications for future therapeutics research.

The deposition of aggregated proteins is a common neuropathological denominator for neurodegenerative disorders. Experimental evidence suggests that disease propagation involves prion-like mechanisms that cause the spreading of template-directed aggregation of specific disease-associated proteins. In transgenic (Tg) mouse models of superoxide dismutase-1 (SOD1)-linked amyotrophic lateral sclerosis (ALS), inoculation of minute amounts of human SOD1 (hSOD1) aggregates into the spinal cord or peripheral nerves induces premature ALS-like disease and template-directed hSOD1 aggregation that spreads along the neuroaxis. This infectious nature of spreading pathogenic aggregates might have implications for the safety of laboratory and medical staff, recipients of donated blood or tissue, or possibly close relatives and caregivers. Here we investigate whether transmission of ALS-like disease is unique to the spinal cord and peripheral nerve inoculations or if hSOD1 aggregation might spread from the periphery into the central nervous system (CNS). We inoculated hSOD1 aggregate seeds into the peritoneal cavity, hindlimb skeletal muscle or spinal cord of adult Tg mice expressing mutant hSOD1. Although we used up to 8000 times higher dose—compared to the lowest dose transmitting disease in spinal cord inoculations—the peripheral inoculations did not transmit seeded aggregation to the CNS or premature ALS-like disease in hSOD1 Tg mice. Nor was any hSOD1 aggregation detected in the liver, kidney, skeletal muscle or sciatic nerve. To explore potential reasons for the lack of disease transmission, we examined the stability of hSOD1 aggregates and found them to be highly vulnerable to both proteases and detergent. Our findings suggest that exposed individuals and personnel handling samples from ALS patients are at low risk of any potential transmission of seeded hSOD1 aggregation. Supplementary Information The online version contains supplementary material available at 10.1186/s40478-021-01211-9.

Increasing evidence suggests that propagation of the motor neuron disease amyotrophic lateral sclerosis (ALS) involves the pathogenic aggregation of disease-associated proteins that spread in a prion-like manner. We have identified two aggregate strains of human superoxide dismutase 1 (hSOD1) that arise in the CNS of transgenic mouse models of SOD1-mediated ALS. Both strains transmit template-directed aggregation and premature fatal paralysis when inoculated into the spinal cord of adult hSOD1 transgenic mice. This spread of pathogenic aggregation could be a potential target for immunotherapeutic intervention. Here we generated mouse monoclonal antibodies (mAbs) directed to exposed epitopes in hSOD1 aggregate strains and identified an aggregate selective mAb that targets the aa 143–153 C-terminal extremity of hSOD1 (αSOD1143–153). Both pre-incubation of seeds with αSOD1143–153 prior to inoculation, and weekly intraperitoneal (i.p.) administration attenuated transmission of pathogenic aggregation and prolonged the survival of seed-inoculated hSOD1G85R Tg mice. In contrast, administration of a mAb targeting aa 65–72 (αSOD165–72), which exhibits high affinity towards monomeric disordered hSOD1, had an adverse effect and aggravated seed induced premature ALS-like disease. Although the mAbs reached similar concentrations in CSF, only αSOD1143–153 was found in association with aggregated hSOD1 in spinal cord homogenates. Our results suggest that an aggregate-selective immunotherapeutic approach may suppress seeded transmission of pathogenic aggregation in ALS. However, long-term administration of αSOD1143–153 was unable to prolong the lifespan of non-inoculated hSOD1G85R Tg mice. Thus, spontaneously initiated hSOD1 aggregation in spinal motor neurons may be poorly accessible to therapeutic antibodies. Originally published in thesis in manuscript form with title: "An aggregate-selective monoclonal antibody attenuates seeded but not spontaneously evolving SOD1 aggregation in ALS model mice" and authors: "Manuela Lehmann, Matthew Marklund, Anna-Lena Bolender, Elaheh E. Bidhendi, Anders Olofsson, Peter M. Andersen, Thomas Brännström, Stefan L. Marklund, Jonathan D. Gilthorpe, Ulrika Nordström"

Absence of SOD1 Activity and Motor Neuron Syndrome In a child with a homozygous truncating mutation in SOD1, SOD1 activity in red cells was absent and fibroblasts grew only with oxygen deprivation....

Objective: Cu/Zn superoxide dismutase (SOD1) reduction prolongs survival in SOD1-transgenic animal models. Pyrimethamine produces dose-dependent SOD1 reduction in cell culture systems. A previous p ...

Amyotrophic lateral sclerosis (ALS) is a lethal neurodegenerative disease that is characterized by the loss of motor neurons, which results in progressive muscle atrophy. The pathology spreads from the initial site of onset to contiguous anatomic regions. Mutations in the gene encoding Cu/Zn-superoxide dismutase (SOD1) have been identified in a dominantly inherited form of ALS (ALS-SOD1). A major hallmark of ALS-SOD1 is the abnormal accumulation of conformationally aberrant SOD1 protein (i.e., misfolded SOD1) within motor neurons. Emerging experimental evidence has suggested that misfolded proteins associated with neurodegenerative diseases exhibit prion-like properties, i.e., misfolded proteins act as conformational templates that convert normal proteins into a pathogenic form. Possibly as a result of this prion-like self-propagation property, misfolded forms of pathological proteins are considered to accumulate in the central nervous system and cause neurodegeneration. In this article, we review recent evidence for the role of prion-like mechanisms in ALS-SOD1. In particular, we discuss the propensity of misfolded SOD1 to act as a pathological seed, spread between cells, and propagate neuroanatomically.

Mutations in the superoxide dismutase (SOD1) gene have been linked to amyotrophic lateral sclerosis (ALS). A 50 base pair (bp) deletion of SOD1 has been suggested to reduce transcription and to be associated with later disease onset in ALS. This study was aimed to reveal if the 50 bp deletion influenced SOD1 enzymatic activity, occurrence and phenotype of the disease in a Swedish ALS/control cohort. Blood samples from 512 Swedish ALS patients and 354 Swedish controls without coding SOD1 mutations were analysed for the 50 bp deletion allele. The enzymatic activity of SOD1 in erythrocytes was analysed and genotype-phenotype correlations were assessed. Results demonstrated that the genotype frequencies of the 50 bp deletion were all found to be in Hardy-Weinberg equilibrium. No significant differences were found for age of onset, disease duration or site of onset. SOD1 enzymatic activity showed a statistically significant decreasing trend in the control group, in which the allele was associated with a 5% reduction in SOD1 activity. The results suggest that the 50 bp deletion has a moderate reducing effect on SOD1 synthesis. No modulating effects, however, were found on ALS onset, phenotype and survival in the Swedish population.

Mutations in superoxide dismutase 1 (SOD1) cause amyotrophic lateral sclerosis (ALS). Disease pathogenesis is linked to destabilization, disorder and aggregation of the SOD1 protein. However, the non-genetic factors that promote disorder and the subsequent aggregation of SOD1 have not been studied. Mainly located to the reducing cytosol, mature SOD1 contains an oxidized disulfide bond that is important for its stability. Since O2 is required for formation of the bond, we reasoned that low O2 tension might be a risk factor for the pathological changes associated with ALS development. By combining biochemical approaches in an extensive range of genetically distinct patient-derived cell lines, we show that the disulfide bond is an Achilles heel of the SOD1 protein. Culture of patient-derived fibroblasts, astrocytes, and induced pluripotent stem cell-derived mixed motor neuron and astrocyte cultures (MNACs) under low O2 tensions caused reductive bond cleavage and increases in disordered SOD1. The effects were greatest in cells derived from patients carrying ALS-linked mutations in SOD1. However, significant increases also occurred in wild-type SOD1 in cultures derived from non-disease controls, and patients carrying mutations in other common ALS-linked genes. Compared to fibroblasts, MNACs showed far greater increases in SOD1 disorder and even aggregation of mutant SOD1s, in line with the vulnerability of the motor system to SOD1-mediated neurotoxicity. Our results show for the first time that O2 tension is a principal determinant of SOD1 stability in human patient-derived cells. Furthermore, we provide a mechanism by which non-genetic risk factors for ALS, such as aging and other conditions causing reduced vascular perfusion, could promote disease initiation and progression. Electronic supplementary material The online version of this article (10.1007/s00401-019-01986-1) contains supplementary material, which is available to authorized users.

Phosphatidylethanol (PEth) is a recently introduced biomarker with high specificity, high sensitivity, and response correlating with alcohol consumption. It has the potential to be a valuable biomarker in population studies on the health effects of alcohol, however its stability in long-term stored blood is not known. We used LC-MS/MS to assess the stability of PEth-16:0/18:1 in blood samples (packed erythrocytes) that were stored between 1 and 19 years at −80 °C in a biobank from a large population survey. The participants answered a life-style questionnaire that included questions on alcohol consumption. For analysis, we selected blood samples from seven homogenous ethanol consumption cohorts collected at intervals from 1997 to 2015. Despite the narrow stated alcohol consumption range, 10–15 g/day, there were large differences in PEth values between individuals in the cohorts, from below the limit of detection of 0.005 µmol/L to 1.40 µmol/L. The median was 0.08 µmol/L. Neither generalized linear modeling, nor principal component analysis revealed a statistically significant association between time of storage and PEth levels. The PEth results indicate that the participants had, on average, under-reported their alcohol consumption several-fold. The findings suggest that PEth in blood has a sufficient long-term stability for use as an alcohol biomarker in prospective case-control studies. Analysis of blood stored in biobanks could significantly improve the validity of assessments exploring the health effects of alcohol.

Amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD) are protein-aggregation diseases that lack clear molecular etiologies. Biomarkers could aid in diagnosis, prognosis, planning of care, drug target identification and stratification of patients into clinical trials. We sought to characterize shared and unique metabolite perturbations between ALS and PD and matched controls selected from patients with other diagnoses, including differential diagnoses to ALS or PD that visited our clinic for a lumbar puncture. Cerebrospinal fluid (CSF) and plasma from rigorously age-, sex- and sampling-date matched patients were analyzed on multiple platforms using gas chromatography (GC) and liquid chromatography (LC)-mass spectrometry (MS). We applied constrained randomization of run orders and orthogonal partial least squares projection to latent structure-effect projections (OPLS-EP) to capitalize upon the study design. The combined platforms identified 144 CSF and 196 plasma metabolites with diverse molecular properties. Creatine was found to be increased and creatinine decreased in CSF of ALS patients compared to matched controls. Glucose was increased in CSF of ALS patients and α-hydroxybutyrate was increased in CSF and plasma of ALS patients compared to matched controls. Leucine, isoleucine and ketoleucine were increased in CSF of both ALS and PD. Together, these studies, in conjunction with earlier studies, suggest alterations in energy utilization pathways and have identified and further validated perturbed metabolites to be used in panels of biomarkers for the diagnosis of ALS and PD.

Despite considerable progress in uncovering the molecular details of protein aggregation in vitro, the cause and mechanism of protein-aggregation disease remain poorly understood. One reason is that the amount of pathological aggregates in neural tissue is exceedingly low, precluding examination by conventional approaches. We present here a method for determination of the structure and quantity of aggregates in small tissue samples, circumventing the above problem. The method is based on binary epitope mapping using anti-peptide antibodies. We assessed the usefulness and versatility of the method in mice modeling the neurodegenerative disease amyotrophic lateral sclerosis, which accumulate intracellular aggregates of superoxide dismutase-1. Two strains of aggregates were identified with different structural architectures, molecular properties, and growth kinetics. Both were different from superoxide dismutase-1 aggregates generated in vitro under a variety of conditions. The strains, which seem kinetically under fragmentation control, are associated with different disease progressions, complying with and adding detail to the growing evidence that seeding, infectivity, and strain dependence are unifying principles of neurodegenerative disease.

Aggregation of mutant superoxide dismutase 1 (SOD1) is a pathological hallmark of a subset of familial ALS patients. However, the possible role of misfolded wild type SOD1 in human ALS is highly debated. To ascertain whether or not misfolded SOD1 is a common pathological feature in non-SOD1 ALS, we performed a blinded histological and biochemical analysis of post mortem brain and spinal cord tissues from 19 sporadic ALS, compared with a SOD1 A4V patient as well as Alzheimer’s disease (AD) and non-neurological controls. Multiple conformation- or misfolded-specific antibodies for human SOD1 were compared. These were generated independently by different research groups and were compared using standardized conditions. Five different misSOD1 staining patterns were found consistently in tissue sections from SALS cases and the SOD1 A4V patient, but were essentially absent in AD and non-neurological controls. We have established clear experimental protocols and provide specific guidelines for working, with conformational/misfolded SOD1-specific antibodies. Adherence to these guidelines will aid in the comparison of the results of future studies and better interpretation of staining patterns. This blinded, standardized and unbiased approach provides further support for a possible pathological role of misSOD1 in SALS.

Objective: To characterise stabilities in erythrocytes of mutant SOD1 proteins, compare SOD1 enzymatic activities between patients with different genetic causes of ALS and search for underlying causes of deviant SOD1 activities in individuals lacking SOD1 mutations. Methods: Blood samples from 4072 individuals, ALS patients with or without a SOD1 mutation, family members and controls were studied. Erythrocyte SOD1 enzymatic activities normalised to haemoglobin content were determined, and effects of haemoglobin disorders on dismutation assessed. Coding SOD1 sequences were analysed by Sanger sequencing, exon copy number variations by fragment length analysis and by TaqMan Assay. Results: Of the 44 SOD1 mutations found, 75% caused severe destabilisation of the mutant protein but in 25% it was physically stable. Mutations producing structural changes caused halved erythrocyte SOD1 activities. There were no differences in SOD1 activities between patients without a SOD1 mutation and control individuals or carriers of TBK1 mutations and C9orf72HRE. In the low and high SOD1 activity groups no deviations were found in exon copy numbers and intron gross structures. Thalassemias and iron deficiency were associated with increased SOD1 activity/haemoglobin ratios. Conclusion: Adjunct erythrocyte SOD1 activity analysis reliably signals destabilising SOD1 mutations including intronic mutations that are missed by exon sequencing.

Motor neurons containing aggregates of superoxide dismutase 1 (SOD1) are hallmarks of amyotrophic lateral sclerosis (ALS) caused by mutations in the gene encoding SOD1. We have previously reported that two strains of mutant human (h) SOD1 aggregates (denoted A and B) can arise in hSOD1-transgenic models for ALS and that inoculation of such aggregates into the lumbar spinal cord of mice results in rostrally spreading, templated hSOD1 aggregation and premature fatal ALS-like disease. Here, we explored whether mutant hSOD1 aggregates with prion-like properties also exist in human ALS. Aggregate seeds were prepared from spinal cords from an ALS patient carrying the hSOD1G127Gfs*7 truncation mutation and from mice transgenic for the same mutation. To separate from mono-, di- or any oligomeric hSOD1 species, the seed preparation protocol included ultracentrifugation through a density cushion. The core structure of hSOD1G127Gfs*7 aggregates present in mice was strain A-like. Inoculation of the patient- or mouse-derived seeds into lumbar spinal cord of adult hSOD1-expressing mice induced strain A aggregation propagating along the neuraxis and premature fatal ALS-like disease (p

We report an apparently sporadic amyotrophic lateral sclerosis patient carrying a heterozygous novel frameshift SOD1 mutation (p.Ser108LeufsTer15), predicted to cause a premature protein truncation. RT-PCR analysis of SOD1 mRNA and SDS-PAGE/Western blot analysis of PBMC demonstrated that mRNA from the mutant allele is expressed at levels similar to those of the wild-type allele, but the truncated protein is undetectable also in the insoluble fraction and after proteasome inhibition. Accordingly, the dismutation activity in erythrocytes is halved. Thus, the pathogenic mechanism associated with this mutation might be based on an insufficient activity of SOD1 that would make motor neurons more vulnerable to oxidative injury. However, it cannot be excluded that p.Ser108LeufsTer15 SOD1 is present in the nervous tissue and, being less charged and hence having less repulsive forces than the wild-type protein, may trigger toxic mechanisms as a consequence of its propensity to aggregate.

A GGGGCC-repeat expansion in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) among Caucasians. However, little is known about the variability of the GGGGCC expansion in different tissues and whether this correlates with the observed phenotype. Here, we used Southern blotting to estimate the size of hexanucleotide expansions in C9orf72 in neural and non-neural tissues from 18 autopsied ALS and FTD patients with repeat expansion in blood. Digitalization of the Southern blot images allowed comparison of repeat number, smear distribution and expansion band intensity between tissues and between patients. We found marked intra-individual variation of repeat number between tissues, whereas there was less variation within each tissue group. In two patients, the size variation between tissues was extreme, with repeat numbers below 100 in all studied non-neural tissues, whereas expansions in neural tissues were 20-40 times greater and in the same size range observed in neural tissues of the other 16 patients. The expansion pattern in different tissues could not distinguish between diagnostic groups and no correlation was found between expansion size in frontal lobe and occurrence of cognitive impairment. In ALS patients, a less number of repeats in the cerebellum and parietal lobe correlated with earlier age of onset and a larger number of repeats in the parietal lobe correlated with a more rapid progression. In 43 other individuals without repeat expansion in blood, we find that repeat sizes up to 15 are stable, as no size variation between blood, brain and spinal cord was found.

Amyotrophic lateral sclerosis (ALS) is an adult-onset degeneration of motor neurons that is commonly caused by mutations in the gene encoding superoxide dismutase 1 (SOD1). Both patients and Tg mice expressing mutant human SOD1 (hSOD1) develop aggregates of unknown importance. In Tg mice, 2 different strains of hSOD1 aggregates (denoted A and B) can arise; however, the role of these aggregates in disease pathogenesis has not been fully characterized. Here, minute amounts of strain A and B hSOD1 aggregate seeds that were prepared by centrifugation through a density cushion were inoculated into lumbar spinal cords of 100-day-old mice carrying a human SOD1 Tg. Mice seeded with A or B aggregates developed premature signs of ALS and became terminally ill after approximately 100 days, which is 200 days earlier than for mice that had not been inoculated or were given a control preparation. Concomitantly, exponentially growing strain A and B hSOD1 aggregations propagated rostrally throughout the spinal cord and brainstem. The phenotypes provoked by the A and B strains differed regarding progression rates, distribution, end-stage aggregate levels, and histopathology. Together, our data indicate that the aggregate strains are prions that transmit a templated, spreading aggregation of hSOD1, resulting in a fatal ALS-like disease.

Introduction: Amyotrophic lateral sclerosis (ALS) and Parkinson’s disease (PD) are two severe neurodegenerative disorders for which the disease mechanisms are poorly understood and reliable biomark ...

A common cause of amyotrophic lateral sclerosis is mutations in superoxide dismutase-1, which provoke the disease by an unknown mechanism. We have previously found that soluble hydrophobic misfolded mutant human superoxide dismutase-1 species are enriched in the vulnerable spinal cords of transgenic model mice. The levels were broadly inversely correlated with life spans, suggesting involvement in the pathogenesis. Here, we used methods based on antihuman superoxide dismutase-1 peptide antibodies specific for misfolded species to explore the composition and amounts of soluble misfolded human superoxide dismutase-1 in tissue extracts. Mice expressing 5 different human superoxide dismutase-1 variants with widely variable structural characteristics were examined. The levels were generally higher in spinal cords than in other tissues. The major portion of misfolded superoxide dismutase-1 was shown to be monomers lacking the C57-C146 disulfide bond with large hydrodynamic volume, indicating a severely disordered structure. The remainder of the misfolded protein appeared to be non-covalently associated in 130- and 250-kDa complexes. The malleable monomers should be prone to aggregate and associate with other cellular components, and should be easily translocated between compartments. They may be the primary cause of toxicity in superoxide dismutase-1-induced amyotrophic lateral sclerosis.

Background: As the lens is constantly exposed to light and oxygen that generate harmful reactive oxygen species, the importance of the intracellular antioxidant enzyme copper-zinc superoxide dismut ...

Objectives: Our objectives were to study the relationship between iron stores, HFE genotypes and the risk for first-ever myocardial infarction. Methods: First-ever myocardial infarction cases (n=61 ...

Several of the superoxide dismutase-1 (SOD1) mutations linked to amyotrophic lateral sclerosis (ALS) lead to synthesis of structurally defective molecules, suggesting that any cytotoxic conformatio ...

We demonstrated that, in vivo, at resting membrane potential, spinal motor neurones of the adult G127X mice do not show an increased excitability. However, when depolarized they show evidence of an ...

Mutant superoxide dismutase-1 (SOD1) causes amyotrophic lateral sclerosis (ALS) through a cytotoxic mechanism of unknown nature. A hallmark in ALS patients and transgenic mouse models carrying human SOD1 (hSOD1) mutations are hSOD1-immunoreactive inclusions in spinal cord ventral horns. The hSOD1 inclusions may block essential cellular functions or cause toxicity through sequestering of other proteins. Inclusions from four different transgenic mouse models were examined after density gradient ultracentrifugation. The inclusions are complex structures with heterogeneous densities and are disrupted by detergents. The aggregated hSOD1 was mainly composed of subunits that lacked the native stabilizing intra-subunit disulfide bond. A proportion of subunits formed hSOD1 oligomers or was bound to other proteins through disulfide bonds. Dense inclusions could be isolated and the protein composition was analyzed using proteomic techniques. Mutant hSOD1 accounted for half of the protein. Ten other proteins were identified. Two were cytoplasmic chaperones, four were cytoskeletal proteins, and 4 were proteins that normally reside in the endoplasmic reticulum (ER). The presence of ER proteins in inclusions containing the primarily cytosolic hSOD1 further supports the notion that ER stress is involved in ALS.

The most common of the amyotrophic lateral sclerosis (ALS)-associated superoxide dismutase-1 (SOD1) mutations, D90A, differs from others in its high structural stability and by the existence of both recessive and dominant inheritance. Here SOD1 in CNS and peripheral organs from five ALS patients homozygous for D90A were compared to controls. In most areas, including ventral horns, there were no significant differences in SOD1 activities and Western blotting patterns between controls and D90A cases. The SOD1 activities in areas vulnerable to mutant SOD1s, ventral horns and precentral gyrus were intermediate among CNS areas and much lower than in kidney and liver. Thus, the vulnerability of motor areas is not explained by high SOD1 content. The findings argue against the idea of expression-reducing protective factors being present near the D90A locus in recessive pedigrees. The similarity to wild-type SOD1 prompts speculations on the involvement of the latter in sporadic ALS.

Antioxidant levels were determined in five patients with the Lesch-Nyhan syndrome. The erythrocyte glutathione peroxidase activity was in average 1.8 times higher in Lesch-Nyhan patients than in controls (1.68 +/- 0.36 versus 0.92 +/- 0.17 mu kat/g hemoglobin, p less than 0.001). Plasma CuZn-superoxide dismutase activity was two times higher (p less than 0.001) and Mn-superoxide dismutase activity was 1.5 times higher (p less than 0.05) than in controls, whilst erythrocyte CuZn-superoxide dismutase, plasma extracellular-superoxide dismutase and lymphocyte superoxide dismutase did not differ between Lesch-Nyhan patients and healthy controls. These data might indicate that Lesch-Nyhan patients are exposed to a higher oxidative load than healthy control persons.

There is a need for biomarkers for early diagnosis, development and evaluation of treatment efficacy in amyotrophic lateral sclerosis (ALS). We aimed to investigate if pre-analytical factors induce artefacts in metabolomic data of cerebrospinal fluid (CSF) from patients with ALS. CSF from 16 patients was studied using a statistical experimental design protocol with the following parameters: storage temperature (-80 degrees C/ - 20 degrees C), type of collection tube (polypropylene/polystyrene), and time delay from collecting to freezing (0, 10, 30, 90, 150 min). Gas chromatography-mass spectrometry was used to analyse CSF from 12 of the patients while CSF from one patient was analysed with nuclear magnetic resonance spectroscopy. The extent of CO(2) evaporization from CSF collected in tubes of different sizes at different temperatures and with/without lid were studied in three addtional patients. We found that alterations in storage temperature affect the metabolite composition of CSF more than any other studied pre-analytical parameter. CO(2) evaporization may induce artefacts in the metabolome by increasing the pH. In conclusion, minimization of evaluated artefacts can be obtained by collecting the CSF directly into tubes with tightly sealed lids in N(2)(l) and after freezing transfer of the tubes to -80 degrees C to minimize evaporation of CO(2).

Targeted delivery of the angiogenic factor, vascular endothelial growth factor (VEGF), to motor neurons prolongs survival in rodent models of amyotrophic lateral sclerosis (ALS), while mice expressing reduced VEGF concentrations develop motor neuron degeneration reminiscent of ALS, raising the question whether VEGF contributes to the pathogenesis of ALS. An initial association study reported that VEGF haplotypes conferred increased susceptibility to ALS in humans, but later studies challenged this initial finding.A meta-analysis was undertaken to critically reappraise whether any of the three common VEGF gene variations (-2578C/A, -1154G/A and -634G/C) increase the risk of ALS. Over 7000 subjects from eight European and three American populations were included in the analysis. Pooled odds ratios were calculated using fixed-effects and random-effects models, and four potential sources of heterogeneity (location of disease onset, gender, age at disease onset and disease duration) were assessed. After correction, none of the genotypes or haplotypes was significantly associated with ALS. Subgroup analysis by gender revealed, however, that the -2578AA genotype, which lowers VEGF expression, increased the risk of ALS in males (OR = 1.46 males vs females; 95% CI = 1.19 to 1.80; p = 7.8 10E-5), even after correction for publication bias and multiple testing.This meta-analysis does not support the original conclusion that VEGF haplotypes increase the risk of ALS in humans, but the significant association of the low-VEGF -2578AA genotype with increased susceptibility to ALS in males reappraises the link between reduced VEGF concentrations and ALS, as originally revealed by the fortuitous mouse genetic studies.

Introduction The motor system is selectively vulnerable to mutations in the ubiquitously expressed aggregation-prone enzyme superoxide dismutase-1 (SOD1). Results Autophagy clears aggregates, and factors involved in the process were analyzed in multiple areas of the CNS from human control subjects (n = 10) and amyotrophic lateral sclerosis (ALS) patients (n = 18) with or without SOD1 mutations. In control subjects, the key regulatory protein Beclin 1 and downstream factors were remarkably scarce in spinal motor areas. In ALS patients, there was evidence of moderate autophagy activation and also dysregulation. These changes were largest in SOD1 mutation carriers. To explore consequences of low autophagy capacity, effects of a heterozygous deletion of Beclin 1 were examined in ALS mouse models expressing mutant SOD1s. This caused earlier SOD1 aggregation, onset of symptoms, motor neuron loss, and a markedly shortened survival. In contrast, the levels of soluble misfolded SOD1 species were reduced. Conclusions The findings suggest that an inherent low autophagy capacity might cause the vulnerability of the motor system, and that SOD1 aggregation plays a crucial role in the pathogenesis. Electronic supplementary material The online version of this article (doi:10.1186/s40478-016-0274-y) contains supplementary material, which is available to authorized users.

Mutants of superoxide dismutase-1 (SOD1) cause ALS by an unidentified cytotoxic mechanism. We have previously shown that the stable SOD1 mutants D90A and G93A are abundant and show the highest levels in liver and kidney in transgenic murine ALS models, whereas the unstable G85R and G127X mutants are scarce but enriched in the CNS. These data indicated that minute amounts of misfolded SOD1 enriched in the motor areas might exert the ALS-causing cytotoxicity. A hydrophobic interaction chromatography (HIC) protocol was developed with the aim to determine the abundance of soluble misfolded SOD1 in tissues in vivo . Most G85R and G127X mutant SOD1s bound in the assay, but only minute subfractions of the D90A and G93A mutants. The absolute levels of HIC-binding SOD1 were, however, similar and broadly inversely related to lifespans in the models. They were generally enriched in the susceptible spinal cord. The HIC-binding SOD1 was composed of disulfide-reduced subunits lacking metal ions and also subunits that apparently carried nonnative intrasubunit disulfide bonds. The levels were high from birth until death and were comparable to the amounts of SOD1 that become sequestered in aggregates in the terminal stage. The HIC-binding SOD1 species ranged from monomeric to trimeric in size. These species form a least common denominator amongst SOD1 mutants with widely different molecular characteristics and might be involved in the cytotoxicity that causes ALS.

We provide bioinformatical evidence that protein charge plays a key role in the disease mechanism of amyotrophic lateral sclerosis (ALS). Analysis of 100 ALS-associated mutations in copper/zinc superoxide dismutase (SOD1) shows that these are site-selective with a preference to decrease the proteins' net repulsive charge. For each SOD1 monomer this charge is normally -6. Because biomolecules as a rule maintain net negative charge to assure solubility in the cellular interior, the result lends support to the hypothesis of protein aggregation as an initiating event in the ALS pathogenesis. The strength of the preferential reduction of repulsive charge is higher in SOD1-associated ALS than in other inherited protein disorders.

Lenses from mice lacking the antioxidant enzyme copper-zinc superoxide dismutase (SOD1) show elevated levels of superoxide radicals and are prone to developing cataract when exposed to high levels of glucose in vitro. As superoxide may react further with nitric oxide, generating cytotoxic reactive nitrogen species, we attempted to evaluate the involvement of nitric oxide in glucose-induced cataract. Lenses from SOD1-null and wild-type mice were incubated with high or normal levels of glucose (55.6 and 5.56 mM). A nitric oxide synthase inhibitor (L-NAME) or a nitric oxide donor (DETA/NO) was added to the culture medium. Cataract development was assessed using digital image analysis of lens photographs and cell damage by analyzing the leakage of lactate dehydrogenase. The levels of superoxide radicals in the lenses were also measured. L-NAME was found to reduce cataract development and cell damage in the SOD1-null lenses exposed to high glucose. On the other hand, DETA/NO accelerated cataract development, especially in the SOD1-null lenses. These lenses also showed a higher leakage of lactate dehydrogenase than wild-type controls. We conclude that a combination of high glucose and absence of SOD1 increases the formation of cataract and that nitric oxide probably contributes to this process.

Background: High iron levels can increase the formation of noxious oxygen radicals, which are thought to contribute to cerebrovascular disease. The aim of this prospective study was to determine if iron status and HFE genotypes constitute risk factors for stroke. Methods: First-ever stroke cases (231 ischemic and 42 hemorrhagic) and matched double referents from the population-based Northern Sweden cohorts were studied in a nested case-referent setting. Results: For total iron binding capacity, an increased risk of ischemic stroke was seen in the highest quartile (OR 1.80; 95% CI 1.14–2.83; p for trend 0.012). The highest quartile of transferrin iron saturation showed a decreased risk of ischemic stroke in men (OR 0.44; 95% CI 0.22–0.87; p for trend 0.028), but not in women. There was an increased risk of hemorrhagic stroke in the second (OR 4.07; 95% CI 1.09–15.20) and third quartile (OR 4.22; 95% CI 1.08–16.42) of ferritin. Neither quartiles of plasma iron concentrations nor the HFE C282Y and H63D genotypes were associated with ischemic or hemorrhagic stroke. Conclusions: Iron stores were not positively related to increased risk of ischemic stroke. Furthermore, HFE genotypes did not influence the risk of ischemic or hemorrhagic stroke.

Oxidative stress has been suggested to contribute to the development of diabetic nephropathy. Manganese superoxide dismutase (MnSOD) protects the cells from oxidative damage by scavenging free radicals. The demand for antioxidants is increased by smoking, which could disturb the balance between antioxidants and radicals. The present study aimed to determine whether a valine/alanine polymorphism in MnSOD (V16A, rs4880), alone or in combination with smoking, can contribute to development of diabetic nephropathy in 1,510 Finnish and Swedish patients with type 1 diabetes. Overt diabetic nephropathy (n = 619) was defined as having an albumin excretion rate (AER) >200 μg/min or renal replacement therapy; incipient diabetic nephropathy was defined as having an AER of 20–200 μg/min (n = 336). The control subjects had diabetes duration of ≥20 years, without albuminuria (AER

Mutant human CuZn-superoxide dismutases (hSOD1s) cause amyotrophic lateral sclerosis (ALS). The most common mutation is the wild type-like D90A and to explore its properties, transgenic mice were generated and compared with mice expressing wild-type hSOD1. D90A hSOD1 was both in vivo in mice and in vitro under denaturing conditions nearly as stable as the wild-type human enzyme. It appeared less toxic than other tested mutants, but mice homozygous for the transgene insertion developed a fatal motor neuron disease. In these mice, the disease progression was slow and there were bladder disturbances similar to what is found in human ALS cases homozygous for the D90A mutation. The homozygous D90A mice accumulated detergent-resistant hSOD1 aggregates in spinal cords, and abundant hSOD1 inclusions and vacuoles were seen in the ventral horns. Mice expressing wild-type hSOD1 at a comparable rate showed similar pathologic changes but less and later. Hemizygous D90A mice showed even milder alterations. At 600 days, the wild-type hSOD1 transgenic mice had lost more ventral horn neurons than hemizygous D90A mice (38% vs 31% p < 0.01). Thus, wild-type hSOD1 shows a significant neurotoxicity in the spinal cord, that is less than equal but more than half as large as that of D90A mutant enzyme.

Mutants of human superoxide dismutase-1 (hSOD1) cause amyotrophic lateral sclerosis (ALS), and mitochondria are thought to be primary targets of the cytotoxic action. The high expression rates of hSOD1s in transgenic ALS models give high levels of the stable mutants G93A and D90A as well as the wild-type human enzyme, significant proportions of which lack Cu and the intrasubunit disulfide bond. The endogenous murine SOD1 (mSOD1) also lacks Cu and is disulfide reduced but is active and oxidized in mice expressing the low-level unstable mutants G85R and G127insTGGG. The possibility that the molecular alterations may cause artificial loading of the stable hSOD1s into mitochondria was explored. Approximately 10% of these hSOD1s were localized to mitochondria, reaching levels 100-fold higher than those of mSOD1 in control mice. There was no difference between brain and spinal cord and between stable mutants and the wild-type hSOD1. mSOD1 was increased fourfold in mitochondria from high-level hSOD1 mice but was normal in those with low levels, suggesting that the Cu deficiency and disulfide reduction cause mitochondrial overloading. The levels of G85R and G127insTGGG mutant hSOD1s in mitochondria were 100- and 1000-fold lower than those of stable mutants. Spinal cords from symptomatic mice contained hSOD1 aggregates covering the entire density gradient, which could contaminate isolated organelle fractions. Thus, high hSOD1 expression rates can cause artificial loading of mitochondria. Unstable low-level hSOD1s are excluded from mitochondria, indicating other primary locations of injury. Such models may be preferable for studies of ALS pathogenesis.

Mice lacking the secreted extracellular superoxide dismutase (EC-SOD) or the cytosolic copper- and zinc-containing SOD (CuZn-SOD) show relatively mild phenotypes. To explore the possibility that the isoenzymes have partly overlapping functions, single and double knockout mice were examined. The absence of EC-SOD was found to be without effect on the lifespan of mice, and the reduced lifespan of CuZn-SOD knockouts was not further shortened by EC-SOD deficiency. The urinary excretion of isoprostanes was increased in CuZn-SOD knockout mice, and plasma thiobarbituric acid-reactive substances levels were elevated in EC-SOD knockout mice. These oxidant stress markers showed potentiated increases in the absence of both isoenzymes. Other alterations were mainly found in CuZn-SOD knockout mice, such as halved glutathione peroxidase activity in the tissues examined and increased glutathione and iron in the liver. There were no changes in tissue content of the alternative superoxide scavenger ascorbate, but there was a 25% reduction in ascorbate in blood plasma in mice lacking CuZn-SOD. No increase was found in the urinary excretion of the terminal metabolites of NO, nitrite, and nitrate in any of the genotypes. In conclusion, apart from the increases in the global urinary and plasma oxidant stress markers, our phenotype studies revealed no other evidence that the copper- and zinc-containing SOD isoenzymes have overlapping roles.

The purpose of this study was to evaluate the involvement of the superoxide radical in glucose-induced cataract using lenses from mice lacking the cytosolic copper-zinc superoxide dismutase (SOD1). Lenses from wild-type mice and SOD1 null mice were kept in organ culture with either 5.6 or 55.6 mM glucose for 6 days. The cataract formation was followed with digital image analysis and ocular staging. The lens damage was further quantified by analysis of the leakage of lactate dehydrogenase into the medium by the uptake of 86Rb and by determining the water content of the lenses. The formation of superoxide radicals in the lenses was assessed with lucigenin-derived chemiluminescence. Immunohistochemical staining for SOD1 was also performed on murine lenses. The SOD1 null lenses exposed to high glucose developed more cataract showed an increased leakage of lactate dehydrogenase and developed more oedema compared to the control lenses. At 5.6 mM glucose there was no difference between the SOD1 null and wild-type lenses. Staining for SOD1 was seen primarily in the cortex of the wild-type lens. This in vitro model suggests an involvement of the superoxide radical and a protective effect of SOD1 in glucose-induced cataract formation.

The ability of glycated hemoglobin A(1c) (HbA(1c)) to predict diabetes is unknown, but could be evaluated by analyses on samples stored in biobanks. The stability of HbA(1c) in long-term stored samples is, however, unknown. Moreover, the effect of hemolysis on HbA(1c) in the general population is not assessed. To explore these questions HbA(1c) was determined in 3 groups (n = 717) of samples with storage times at -80 degrees C differing between 10 years and 2 months. The results were compared with HbA(1c) analyzed in fresh blood samples (n = 174). The subjects were free from diabetes and aged 40 to 60 years. HbA(1c) was analyzed by cation exchange high-performance liquid chromatography (HPLC). The mean HbA(1c) results for the fresh and long-term stored samples were 4.25% +/- 0.39 and 4.19% +/- 0.43, respectively (P = not significant [NS]). The HbA(1c) levels in fresh and 2-month stored samples were essentially equal. There was no correlation between HbA(1c) in the fresh samples and the hemolysis parameters reticulocytes, haptoglobin, or bilirubin. HbA(1c) is apparently stable in samples long-term stored at -80 degrees C and is not commonly affected by hemolysis in the general population. HbA(1c) analyzed on biobank samples could be used to assess the predictive value for future diabetes and relationship to other morbidity and mortality.

5'-AMP-activated protein kinase (AMPK) is a metabolic stress sensor present in all eukaryotes. A dominant missense mutation (R225Q) in pig PRKAG3, encoding the muscle-specific gamma3 isoform, causes a marked increase in glycogen content. To determine the functional role of the AMPK gamma3 isoform, we generated transgenic mice with skeletal muscle-specific expression of wild type or mutant (225Q) mouse gamma3 as well as Prkag3 knockout mice. Glycogen resynthesis after exercise was impaired in AMPK gamma3 knock-out mice and markedly enhanced in transgenic mutant mice. An AMPK activator failed to increase skeletal muscle glucose uptake in AMPK gamma3 knock-out mice, whereas contraction effects were preserved. When placed on a high fat diet, transgenic mutant mice but not knock-out mice were protected against excessive triglyceride accumulation and insulin resistance in skeletal muscle. Transfection experiments reveal the R225Q mutation is associated with higher basal AMPK activity and diminished AMP dependence. Our results validate the muscle-specific AMPK gamma3 isoform as a therapeutic target for prevention and treatment of insulin resistance.

VEGF is a modifier of amyotrophic lateral sclerosis in mice and humans and protects motoneurons against ischemic death.Lambrechts D, Storkebaum E, Morimoto M, Del-Favero J, Desmet F, Marklund SL, Wyns S, Thijs V, Andersson J, van Marion I, Al-Chalabi A, Bornes S, Musson R, Hansen V, Beckman L, Adolfsson R, Pall HS, Prats H, Vermeire S, Rutgeerts P, Katayama S, Awata T, Leigh N, Lang-Lazdunski L, Dewerchin M, Shaw C, Moons L, Vlietinck R, Morrison KE, Robberecht W, Van Broeckhoven C, Collen D, Andersen PM, Carmeliet P.The Center for Transgene Technology and Gene Therapy, Flanders Interuniversity Institute for Biotechnology and Department of Neurology, University Hospital Gasthuisberg, KU Leuven, Leuven, B-3000, Belgium.Amyotrophic lateral sclerosis (ALS) is an incurable degenerative disorder of motoneurons. We recently reported that reduced expression of Vegfa causes ALS-like motoneuron degeneration in Vegfa(delta/delta) mice. In a meta-analysis of over 900 individuals from Sweden and over 1,000 individuals from Belgium and England, we now report that subjects homozygous with respect to the haplotypes -2,578A/-1,154A/-634G or -2,578A/-1,154G/-634G in the VEGF promoter/leader sequence had a 1.8 times greater risk of ALS (P = 0.00004). These 'at-risk' haplotypes lowered circulating VEGF levels in vivo and reduced VEGF gene transcription, IRES-mediated VEGF expression and translation of a novel large-VEGF isoform (L-VEGF) in vivo. Moreover, SOD1(G93A) mice crossbred with Vegfa(delta/delta) mice died earlier due to more severe motoneuron degeneration. Vegfa(delta/delta) mice were unusually susceptible to persistent paralysis after spinal cord ischemia, and treatment with Vegfa protected mice against ischemic motoneuron death. These findings indicate that VEGF is a modifier of motoneuron degeneration in human ALS and unveil a therapeutic potential of Vegfa for stressed motoneurons in mice.

Oxygen free radicals apparently play important roles in diseases of the blood vessel wall and increased secretion of superoxide radicals occurs in many situations. The vascular wall contains large amounts of extracellular superoxide dismutase (EC-SOD). The synthesis of the enzyme by the smooth muscle cells (SMC) is modulated by cytokines, growth factors, and vasoactive factors. Here we studied the effects of oxidants (pyrogallol, xanthine oxidase, Cu and Fe), antioxidants (SOD, catalase, and ascorbate), glutathione modulation ( n -acetylcysteine and buthionine sulfoximine) and nitric oxide on EC-SOD expression by human vascular SMCs. Generally, the responses in EC-SOD synthesis were small, and no changes were noted in mRNA levels. High concentrations of some of the agents caused reductions in EC-SOD synthesis, mostly concomitantly with toxic effects on the cells. Cell cultures are normally ascorbate deficient, and addition of ascorbate to approach physiological levels doubled the EC-SOD content. Iron ions up-regulated EC-SOD synthesis but also blocked the secretion of the enzyme. Only down-regulation was found by NO -releasing compounds. In conclusion, there is limited response to oxidant stress of EC-SOD synthesis by SMCs on a cell-autonomous level. The synthesis appears mainly regulated by factors coordinating concerted tissue responses.

Mucosal tissue damage and dysfunction in chronic inflammatory bowel disease (IBD) are partly caused by an enduring exposure to excessive amounts of reactive oxygen metabolites (ROMs). Although the three human isoforms of superoxide dismutase (SOD), copper/zinc (Cu/Zn)-SOD, manganese (Mn)-SOD, and extracellular (EC)-SOD, form the primary endogenous defence against ROMs, their expression levels and cellular localization in IBD mucosa are largely unknown. The present study used enzyme-linked immunosorbent assays (ELISAs), spectrophotometric activity assays, and immunohistochemistry to evaluate the protein concentration, enzymatic activity, and distribution of Cu/Zn-, Mn-, and EC-SOD in paired inflamed and non-inflamed mucosal resection specimens of patients with Crohn's disease (CD) or ulcerative colitis (UC) and compared these with the levels obtained in normal control mucosa. Gut mucosal SOD isoform expression was found to be differentially affected in IBD patients, without major differences between CD and UC. A marked step-wise increase in Mn-SOD protein levels was observed in non-inflamed and inflamed IBD mucosae, whereas the Cu/Zn-SOD content decreased with inflammation. EC-SOD was only found in low amounts, which tended to be decreased in IBD patients. Immunohistochemical evaluation confirmed these observations. Mn-SOD and Cu/Zn-SOD were both predominantly expressed in intestinal epithelial cells and the percentage of epithelial cells positive for Mn-SOD was considerably increased in IBD, whereas epithelial Cu/Zn-SOD expression was much less affected. Within the lamina propria, SOD expression was much lower. Cu/Zn-SOD and Mn-SOD were prominently present in neutrophils and macrophages, and EC-SOD was mainly localized in small vessels, stromal cells, and neutrophils. The percentage of lamina propria cells positive for Cu/Zn-, Mn-, or EC-SOD was not affected by inflammation. Enzyme activity measurements showed consistent results for Cu/Zn-SOD and EC-SOD, but the activity of Mn-SOD did not concordantly increase with the immunological assessments, which may indicate that a proportion of the Mn-SOD in IBD is present in an enzymatically inactive form. This study reveals remarkable changes in the expression levels of the three SOD isoforms in IBD, particularly in the epithelium. Disturbances in the carefully orchestrated mucosal antioxidant cascade may contribute to the induction and perpetuation of intestinal inflammation in IBD, and may have important implications for the development of antioxidant treatment of IBD patients.

The diagnosis of gastrointestinal graft versus host disease (GI-GVHD) is based on clinical symptoms and histological findings. In clinical practice, it is often difficult to decide whether abdominal symptoms in an allogeneic transplant recipient are caused by GVHD or other disorders. Endoscopic biopsies are helpful in establishing the diagnosis, but endoscopy is not always possible to perform due to poor general condition of the patients. No biomarkers are routinely used to predict GVHD. The aim of fecal calprotectin and alpha-1 antitrypsin testing in our study was to find out whether determination of the concentrations of these proteins may be used as a screening method for enteric GVHD. We studied prospectively 51 patients, 8 of whom developed GI-GVHD. Our data demonstrate that elevated fecal calprotectin levels were significantly associated with presence of GI-GVHD. We found a positive association between high F-calprotectin and severe gastrointestinal GVHD. In bivariate analysis, only calprotectin but not alpha-1 antitrypsin was independently associated with GI-GVHD. Testing for fecal calprotectin after allogeneic stem cell transplantation may be a useful screening tool.

In some families with amyotrophic lateral sclerosis (ALS), the disease is linked to mutations in the gene encoding CuZn-superoxide dismutase. The mutant CuZn-superoxide dismutases appear to cause motor neuron degeneration by a toxic property, suggested to be linked to an altered reactivity of the active-site Cu ions. Asp90Ala mutant CuZn-superoxide dismutase was isolated from six patients with ALS, allowing properties of the mutant enzyme synthesized and conditioned in patients with ALS to be examined. The molecular mass of the Asp90Ala mutant CuZn-superoxide dismutase was 45 Da lower than that of the wild-type enzyme, as expected from the amino acid exchange. The mobility after sodium dodecyl sulfate-polyacrylamide gel electrophoresis was markedly increased, however, suggesting altered properties of the polypeptide. The mutant CuZn-superoxide dismutase showed a minimal reduction in stability but did not differ significantly from the wild-type enzyme in enzymic activity, in content and affinity for active-site Cu ions and in the propensity to catalyze formation of hydroxyl radicals. Our findings suggest that the deleterious effect of mutant CuZn-superoxide dismutases on motor neurons in ALS is not related to altered reactivity of active-site Cu ions, resulting in increased oxidant stress. Attention should therefore also be directed at other mechanisms and properties of the mutant polypeptides and their degradation products.

Objectives With the present studies we sought to determine how treatment with nitroglycerin (NTG) affects endothelial function, oxidative stress and nitric oxide (NO)-downstream signaling in Watanabe heritable hyperlipidemic rabbits (WHHL). Background In vitro experiments have demonstrated potent antiatherosclerotic effects of NO suggesting that treatment with NO-donors such as NTG could compensate for the diminished availability of endothelial NO. Nitric oxide may, however, not only be scavenged by reaction with endothelium-derived superoxide but also form the potent oxidant and inhibitor of vascular function, peroxynitrite (ONOO-). Methods Watanabe heritable hyperlipidemic rabbits were treated for three days with NTG patches. Normolipidemic New Zealand White rabbits (NZWR) served as controls. Endothelial function was assessed ex vivo with organ chamber experiments and vascular superoxide was quantified using lucigenin (5 and 250 μM) and CLA-enhanced chemiluminescence. Vascular ONOO- formation was determined using nitrotyrosine antibodies. The activity of the cGMP-dependent kinase (cGK-I) was assessed by determining the phosphorylation of vasodilator-stimulated phosphoprotein VASP (P-VASP). Results Nitroglycerin treatment caused endothelial dysfunction in NZWR and WHHL, associated with an increase in superoxide and ONOO- production and a substantial drop in cGK-I activity. In vivo NTG-treatment decreased lipophilic antioxidants (α- and β-carotene) in NZWR and WHHL. Treatment of NZWR with NTG also decreased plasma extracellular superoxide dismutase (EC-SOD)-activity. Conclusions Nitroglycerin treatment of WHHL with exogenous NO worsens rather than improves endothelial dysfunction secondary to increased formation of superoxide and/or peroxynitrite leading to decreased cGK-I activity. The decrease in plasma levels of α- and β-carotene may be at least in part due to a decrease in EC-SOD activity.

Extracellular-superoxide dismutase (EC-SOD) exists primarily in the tissue interstitium and the lung contains particularly large amounts of the enzyme. To determine the roles of EC-SOD and extracellularly formed superoxide radicals in the pulmonary response to the common air pollutant ozone, wild-type mice and mice lacking EC-SOD were exposed to 1·5 ppm ozone for 48 h. The exposure resulted in a marked neutrophilic inflammatory reaction observed both in the bronchoalveolar lavage fluid (BALF) and by histopathology of the lungs, which was much stronger in the mice lacking EC-SOD. Unlike the wild-type mice, the null mutants also showed increased levels of interleukin-6 in the BALF. The ozone exposure also resulted in increased airway mucosal permeability and cell damage as indicated by increased protein and lactate dehydrogenase in the BALF. There was, however, no difference between the two groups of mice. The results suggest that extracellular superoxide radicals are important inflammatory mediators in the pulmonary response to ozone, but in the present model, the radical and the infiltrating neutrophils contributed little to the pulmonary injury. The data, together with previous findings, support a role for EC-SOD as a modulator of inflammatory reactions.

High intake of fish has been associated with reduced risk of CHD. The high content of n-3 polyunsaturated fatty acids (PUFA) in fish has been suggested to be a protective factor. In addition, fish is the entirely dominating source of methylmercury for the general population, and the concentration of Hg in erythrocytes (Ery-Hg) is often used as an index of fish consumption. Our aim was to study the relationships between a first-ever myocardial infarction, Ery-Hg, activity of gluthathione peroxidase in erythrocytes (Ery-GSH-Px) and plasma concentration of the n-3 PUFA eicosapentaenoic and docosahexaenoic acids (P-PUFA). In a population-based prospective nested case–control study within Northern Sweden seventy-eight cases of a first-ever myocardial infarction were compared with 156 controls with respect to Ery-Hg, P-PUFA and Ery-GSH-Px. Both Ery-Hg and P-PUFA, but not Ery-GSH-Px, were significantly (P