Attention-deficit hyperactivity disorder (ADHD) in adults is associated with impaired sleep, and it has been postulated that this impairment may contribute to the psychopathology of this common condition. One key driver of sleep/wake cycles is the circadian system, which at the molecular level consists of a series of transcriptional feedback loops of clock genes, which in turn produce endocrine, physiological and behavioural outputs with a near 24 h periodicity. We set out to examine circadian rhythms at the behavioural, endocrine and molecular levels in ADHD. Adults with ADHD as well as age-and sex-matched controls were recruited. Circadian rhythms were measured by means of actigraphy for the determination of gross motor patterns, by self-sampling of oral mucosa for assessment of rhythmic expression of the clock genes BMAL1 and PER2, and by estimation of salivary cortisol and melatonin levels. Actigraphic analysis revealed significant diurnal and nocturnal hyperactivity in the ADHD group, as well as a significant shorter period of best fit for the locomotor circadian rhythm in ADHD. BMAL1 and PER2 showed circadian rhythmicity in controls with this being lost in the ADHD group. Cortisol rhythms were significantly phase delayed in the ADHD group. These findings indicate that adult ADHD is accompanied by significant changes in the circadian system, which in turn may lead to decreased sleep duration and quality in the condition. Further, modulation of circadian rhythms may represent a novel therapeutic avenue in the management of ADHD.

Microglial priming predisposes the brain to neurodegeneration and affects disease progression. The signal to switch from the quiescent to the primed state is unknown. We show that deleting the C3 convertase regulator complement receptor 1-related protein y (Crry) induces microglial priming. Mice that were double-knockout for Crry and either C3 or factor B did not show priming, demonstrating dependence on alternative pathway activation. Colocalization of C3b/ iC3b and CR3 implicated the CR3/iC3b interaction in priming. Systemic lipopolysaccharide challenge overactivated primed microglia with florid expression of proinflammatory molecules, which were blocked by complement inhibition. Relevance for neurodegenerative disease is exemplified by human multiple sclerosis (MS) and by experimental autoimmune encephalomyelitis (EAE), a model of MS. In human MS, microglial priming was evident in perilesional white matter, in close proximity to C3b/iC3b deposits. EAE was accelerated and exacerbated in Crry-deficient mice, and was dependent on C activation. In summary, C3-dependent microglial priming confers susceptibility to other challenges. Our observations are relevant to progression in MS and other neurological diseases exacerbated by acute insults.

Constitutive heterochromatin mainly consists of different classes of satellite DNAs and is defined as a transcriptionally inactive chromatin that remains compact throughout the cell cycle. The aim of this work was to investigate the level of condensation, methylation and transcriptional status of centromeric (alphoid DNA) and pericentromeric satellites (human satellite 3, HS3) in tissues (lymphocytes, placenta cells) and in cultured primary (MRC5, VH-10, AT2Sp) and malignant (A431) cells. We found that alphoid DNA remained condensed and heavily methylated in all the cell types. The HS3 of chromosome 1 (HS3-1) but not of chromosome 9 (HS3-9) was strongly decondensed and demethylated in A431 cells. The same observation was made for aged embryonic lung (MRC5) and juvenile foreskin (VH-10) fibroblasts obtained at late passages (32^nd and 23^rd, respectively). Decondensation was also found in ataxia telangiectasia AT2Sp fibroblasts at the 16^th passage. One of the manifestations of the disease is premature aging. The level of HS3-1 decondensation was higher in aged primary fibroblasts as compared to A431. The HS3-1 extended into the territory of neighbouring chromosomes. An RT-PCR product was detected in A431 and senescent MRC5 fibroblasts using primers specific for HS3-1. The RNA was polyadenylated and transcribed from the reverse chain. Our results demonstrate the involvement of satellite DNA in associations between human chromosomes and intermingling of chromosome territories. The invading satellite DNA can undergo decondensation to a certain level. This process is accompanied by demethylation and transcription.

Gene-deleted mice have provided a potent tool in efforts to understand the roles of complement and complement-regulating proteins in vivo. In particular, mice deficient in the membrane regulators complement receptor 1-related gene/protein y, decay-accelerating factor, or CD59 have demonstrated homeostatic relevance and backcrossing between the strains has revealed cooperativity in regulation. In mouse, genes encoding decay-accelerating factor and CD59 have been duplicated and show differential expression in tissues, complicating interpretation and extrapolation of findings to man. The first described form of CD59, CD59a, is broadly distributed and deletion of the cd59a gene causes a mild hemolytic phenotype with increased susceptibility in complement-mediated disease models. The distribution of the second form, CD59b, was originally described as testis specific, but later by some as widespread. Deletion of the cd59b gene caused a severe hemolytic and thrombotic phenotype. To apply data from these mouse models to man it is essential to know the relative distribution and functional roles of these two forms of CD59. We have generated new specific reagents and used them in sensitive quantitative analyses to comprehensively characterize expression of mRNA and protein and functional roles of CD59a and CD59b in wild-type (wt) and CD59a-negative mice. cd59b mRNA was detected only in testis and, at very low levels, in bone marrow. CD59b protein was present on mature spermatozoa and precursors and, in trace amounts, erythrocytes. Erythrocyte CD59b did not inhibit complement lysis except when CD59a was absent or blocked. These data confirm that CD59a is the primary regulator of complement membrane attack in mouse.

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The b-amyloid peptide (Ab) that accumulates in senile plaques in Alzheimer's disease is formed by cleavage of the amyloid precursor protein (APP). The APP gene has several intronic Alu elements inserted in either the sense or antisense orientation. In this study, we demonstrate that binding of SC35 and hnRNPA1 to Alu elements on either side of exon 7 in the transcribed pre-mRNA is involved in alternative splicing of APP exons 7 and 8. Neuronal cells transfected with the full-length form of APP secrete higher levels of Ab than cells transfected with the APP695 isoform lacking exons 7 and 8. Finally, we show that treatment of neuronal cells with estradiol results in increased expression of APP695, SC35 and hnRNPA1, and lowers the level of secreted Ab. An understanding of the regulation of splicing of APP may lead to the identification of new targets for treating Alzheimer's disease.

Alzheimer’s disease (AD) is an age-related neurodegenerative disease that affects approximately 24 million people worldwide. A number of different risk factors have been implicated in AD; however, neuritic (amyloid) plaques are considered as one of the defining risk factors and pathological hallmarks of the disease. In the past decade, enormous efforts have been devoted to understand the genetics and molecular pathogenesis leading to neuronal death in AD, which has been transferred into extensive experimental approaches aimed at reversing disease progression. Modern medicine is facing an increasing number of treatments available for vascular and neurodegenerative brain diseases, but no causal or neuroprotective treatment has yet been established. Almost all neurological conditions are characterized by progressive neuronal dysfunction, which, regardless of the pathogenetic mechanism, finally leads to neuronal death. The particular emphasis of this review is on risk factors and mechanisms resulting in neuronal loss in AD and current and prospective opportunities for therapeutic interventions. This review discusses these issues with a view to inspiring the development of new agents that could be useful for the treatment of AD.

Recently, there has been an increase of interest in the use of biological or immune-based therapies for patients with malignancies. This has been informed by the deeper understanding of the crosstalk between the host immune system and malignant tumours, as well as the potential advantages of immunotherapy-high specificity and less toxicity compared to standard approaches. The particular emphasis of this article is on the role of the complement system in tumour growth and antibody-based cancer immunotherapy. The functional consequences from overexpression of complement regulators by tumours and the development of strategies for overcoming this are discussed in detail. This review discusses these issues with a view to inspiring the development of new agents that could be useful for the treatment of cancer.