A human-derived antibody targets misfolded SOD1 and ameliorates motor symptoms in mouse models of amyotrophic lateral sclerosis.

Mutations in the gene encoding superoxide dismutase 1 (SOD1) lead to misfolding and aggregation of SOD1 and cause familial amyotrophic lateral sclerosis (FALS). However, the implications of wild-type SOD1 misfolding in sporadic forms of ALS (SALS) remain unclear. By screening human memory B cells from a large cohort of healthy elderly subjects, we generated a recombinant human monoclonal antibody (α-miSOD1) that selectively bound to misfolded SOD1, but not to physiological SOD1 dimers. On postmortem spinal cord sections from 121 patients with ALS, α-miSOD1 antibody identified misfolded SOD1 in a majority of cases, regardless of their SOD1 genotype. In contrast, the α-miSOD1 antibody did not bind to its epitope in most of the 41 postmortem spinal cord sections from non-neurological control (NNC) patients. In transgenic mice overexpressing disease-causing human SOD1G37R or SOD1G93A mutations, treatment with the α-miSOD1 antibody delayed the onset of motor symptoms, extended survival by up to 2 months, and reduced aggregation of misfolded SOD1 and motor neuron degeneration. These effects were obtained whether α-miSOD1 antibody treatment was administered by direct brain infusion or peripheral administration. These results support the further development of α-miSOD1 antibody as a candidate treatment for ALS involving misfolding of SOD1.

High-speed video gait analysis reveals early and characteristic locomotor phenotypes in mouse models of neurodegenerative movement disorders.

Neurodegenerative diseases of the central nervous system frequently affect the locomotor system resulting in impaired movement and gait. In this study we performed a whole-body high-speed video gait analysis in three different mouse lines of neurodegenerative movement disorders to investigate the motor phenotype. Based on precise computerized motion tracking of all relevant joints and the tail, a custom-developed algorithm generated individual and comprehensive locomotor profiles consisting of 164 spatial and temporal parameters. Gait changes observed in the three models corresponded closely to the classical clinical symptoms described in these disorders: Muscle atrophy due to motor neuron loss in SOD1 G93A transgenic mice led to gait characterized by changes in hind-limb movement and positioning. In contrast, locomotion in huntingtin N171-82Q mice modeling Huntington's disease with basal ganglia damage was defined by hyperkinetic limb movements and rigidity of the trunk. Harlequin mutant mice modeling cerebellar degeneration showed gait instability and extensive changes in limb positioning. Moreover, model specific gait parameters were identified and were shown to be more sensitive than conventional motor tests. Altogether, this technique provides new opportunities to decipher underlying disease mechanisms and test novel therapeutic approaches.

Acute Effects of Muscarinic M1 Receptor Modulation on AßPP Metabolism and Amyloid-ß Levels in vivo: A Microdialysis Study.

Indirect modulation of cholinergic activity by cholinesterase inhibition is currently a widely established symptomatic treatment for Alzheimer's disease (AD). Selective activation of certain muscarinic receptor subtypes has emerged as an alternative cholinergic-based amyloid-lowering strategy for AD, as selective muscarinic M1 receptor agonists can reduce amyloid-ß (Aß) production by shifting endoproteolytic amyloid-ß protein precursor (AßPP) processing toward non-amyloidogenic pathways. In this study, we addressed the hypothesis that acute stimulation of muscarinic M1 receptors can inhibit Aß production in awake and freely moving AßPP transgenic mice. By combining intracerebral microdialysis with retrodialysis, we determined hippocampal Aß concentrations during simultaneous pharmacological modulation of brain M1 receptor function. Infusion with a M1 receptor agonist AF102B resulted in a rapid reduction of interstitial fluid (ISF) Aß levels while treatment with the M1 antagonist dicyclomine increased ISF Aß levels reaching significance within 120 minutes of treatment. The reduction in Aß levels was associated with PKCα and ERK activation resulting in increased levels of the α-secretase ADAM17 and a shift in AßPP processing toward the non-amyloidogenic processing pathway. In contrast, treatment with the M1 receptor antagonist dicyclomine caused a decrease in levels of phosphorylated ERK that was independent of PKCα, and led to an elevation of ß-secretase levels associated with increased amyloidogenic AßPP processing. The results of this study demonstrate rapid effects of in vivo M1 receptor modulation on the ISF pool of Aß and suggest that intracerebral microdialysis with retrodialysis is a useful technical approach for monitoring acute treatment effects of muscarinic receptor modulators on AßPP/Aß metabolism.

Amyloid-ß peptide-specific DARPins as a novel class of potential therapeutics for Alzheimer disease.

Passive immunization with anti-amyloid-ß peptide (Aß) antibodies is effective in animal models of Alzheimer disease. With the advent of efficient in vitro selection technologies, the novel class of designed ankyrin repeat proteins (DARPins) presents an attractive alternative to the immunoglobulin scaffold. DARPins are small and highly stable proteins with a compact modular architecture ideal for high affinity protein-protein interactions. In this report, we describe the selection, binding profile, and epitope analysis of Aß-specific DARPins. We further showed their ability to delay Aß aggregation and prevent Aß-mediated neurotoxicity in vitro. To demonstrate their therapeutic potential in vivo, mono- and trivalent Aß-specific DARPins (D23 and 3×D23) were infused intracerebroventricularly into the brains of 11-month-old Tg2576 mice over 4 weeks. Both D23 and 3×D23 treatments were shown to result in improved cognitive performance and reduced soluble Aß levels. These findings demonstrate the therapeutic potential of Aß-specific DARPins for the treatment of Alzheimer disease.

The role of cognitive impairment in general functioning in major depression.

The association between cognitive performance and general functioning in depression is controversial. The present study evaluated the association between cognitive dysfunction and major depressive disorder (MDD, N=70) as compared with age- and gender-matched healthy controls (n=206) and its relationship to general functioning (physical and mental health quality of life, activities of daily living, and employment status) in participants with current MDD (n=26) and those with previous MDD only (n=44). Participants were assessed clinically using the Mini International Neuropsychiatric Interview (M.I.N.I.) for the depression groups and the Diagnostic Interview for Psychoses (DIP-DM) for the control group. Measures to evaluate cognition and quality of lifes comprised the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), the Short Form-36 Health Survey Questionnaire, and the Activities/Instrumental Activities of Daily Living (ADL/IADL); employment status was also assessed in MDD. The results showed that a) while individuals with current depression had worse cognitive performance in all domains than healthy controls, those individuals with previous depression had lasting cognitive impairments in the domains of immediate memory and attention as compared with healthy controls; b) individuals with current depression had lower scores in the visuospatial/constructional and attention domains and the total score than individuals with previous depression; c) individuals in the depression group as a whole who were currently unemployed had significantly lower scores in all domains (except attention) of cognitive function; d) cognitive function was not related to either physical or mental quality of life or impairments of activities of daily living (ADL, IADL); e) that unemployment in previous depression was related to poor cognitive function similar to those with current depression. The results indicate that MDD may have detrimental and lasting effects on cognitive performance partly related to poorer general functioning.

Impact of psychiatric and medical comorbidity on cognitive function in depression.

AIM: The aim of the present study was to investigate the association between cognitive performance and psychiatric and medical comorbidity in major depression. METHODS: The present study evaluated the cognitive performance of patients (n = 96) diagnosed with a major depressive episode in relation to the presence of medical and/or psychiatric comorbidity. Participants were assessed clinically and cognitively using the Mini International Neuropsychiatric Interview and Repeatable Battery for the Assessment of Neuropsychological Status. Four groups of comorbidity were categorized: (i) no comorbidity, (ii) medical comorbidity; (iii) psychiatric comorbidity; and (iv) both medical and psychiatric comorbidity, and subsequently analyzed for differences across six cognitive domains: immediate memory, visuospatial, language, attention, delayed memory, and total score. RESULTS: Only 20.8% of the participants did not have a comorbidity of any kind, while psychiatric comorbidities (67.7%) were more frequent than medical comorbidities (39.6%). Education and severity of depressive symptoms negatively influenced cognitive performance. Psychiatric comorbidity alone significantly decreased cognitive performance in the visuospatial/constructional and the language domains and the total score. In addition, increasing numbers of psychiatric comorbidities were related to worse cognitive performance. In contrast, medical illnesses alone had no negative impact on any of the domains of cognitive performance. Evidence was found for additive effects of medical and psychiatric comorbidities in depression on visuospatial/constructional cognitive abilities. CONCLUSION: The strongest predictor of poor cognitive performance in depression was psychiatric comorbidity. The assessment and treatment of cognitive dysfunction in depression should consider the relative impact of psychiatric comorbidity.