VEGF expression disparities in brainstem motor neurons of the SOD1G93A ALS model: Correlations with neuronal vulnerability.

Amyotrophic lateral sclerosis (ALS) is a rare neuromuscular disease characterized by severe muscle weakness mainly due to degeneration and death of motor neurons. A peculiarity of the neurodegenerative processes is the variable susceptibility among distinct neuronal populations, exemplified by the contrasting resilience of motor neurons innervating the ocular motor system and the more vulnerable facial and hypoglossal motor neurons. The crucial role of vascular endothelial growth factor (VEGF) as a neuroprotective factor in the nervous system is well-established since a deficit of VEGF has been related to motoneuronal degeneration. In this study, we investigated the survival of ocular, facial, and hypoglossal motor neurons utilizing the murine SOD1G93A ALS model at various stages of the disease. Our primary objective was to determine whether the survival of the different brainstem motor neurons was linked to disparate VEGF expression levels in resilient and susceptible motor neurons throughout neurodegeneration. Our findings revealed a selective loss of motor neurons exclusively within the vulnerable nuclei. Furthermore, a significantly higher level of VEGF was detected in the more resistant motor neurons, the extraocular ones. We also examined whether TDP-43 dynamics in the brainstem motor neuron of SOD mice was altered. Our data suggests that the increased VEGF levels observed in extraocular motor neurons may potentially underlie their resistance during the neurodegenerative processes in ALS in a TDP-43-independent manner. Our work might help to better understand the underlying mechanisms of selective vulnerability of motor neurons in ALS.

Redistribution of FLAgellar Member 8 during the trypanosome life cycle: Consequences for cell fate prediction.

The single flagellum of African trypanosomes is essential in multiple aspects of the parasites' development. The FLAgellar Member 8 protein (FLAM8), localised to the tip of the flagellum in cultured insect forms of Trypanosoma brucei, was identified as a marker of the locking event that controls flagellum length. Here, we investigated whether FLAM8 could also reflect the flagellum maturation state in other parasite cycle stages. We observed that FLAM8 distribution extended along the entire flagellar cytoskeleton in mammalian-infective forms. Then, a rapid FLAM8 concentration to the distal tip occurs during differentiation into early insect forms, illustrating the remodelling of an existing flagellum. In the tsetse cardia, FLAM8 further localises to the entire length of the new flagellum during an asymmetric division. Strikingly, in parasites dividing in the tsetse midgut and in the salivary glands, the amount and distribution of FLAM8 in the new flagellum were seen to predict the daughter cell fate. We propose and discuss how FLAM8 could be considered a meta-marker of the flagellum stage and maturation state in trypanosomes.

Variation in Basal Body Localisation and Targeting of Trypanosome RP2 and FOR20 Proteins.

TOF-LisH-PLL motifs define FOP family proteins; some members are involved in flagellum assembly. The critical role of FOP family protein FOR20 is poorly understood. Here, we report relative localisations of the four FOP family proteins in parasitic Trypanosoma brucei: TbRP2, TbOFD1 and TbFOP/FOP1-like are mature basal body proteins whereas TbFOR20 is present on pro- and mature basal bodies - on the latter it localises distal to TbRP2. We discuss how the data, together with published work for another protist Giardia intestinalis, informs on likely FOR20 function. Moreover, our localisation study provides convincing evidence that the antigen recognised by monoclonal antibody YL1/2 at trypanosome mature basal bodies is FOP family protein TbRP2, not tyrosinated α-tubulin as widely stated in the literature. Curiously, FOR20 proteins from T. brucei and closely related African trypanosomes possess short, negatively-charged N-terminal extensions absent from FOR20 in other trypanosomatids and other eukaryotes. The extension is necessary for protein targeting, but insufficient to re-direct TbRP2 to probasal bodies. Yet, FOR20 from the American trypanosome T. cruzi, which lacks any extension, localises to pro- and mature basal bodies when expressed in T. brucei. This identifies unexpected variation in FOR20 architecture that is presently unique to one clade of trypanosomatids.

Inequalities in the Impact of National Reimbursement of Smoking Cessation Pharmacotherapy and the Influence of Injunctive Norms: An Explorative Study.

In 2011, the Dutch government reimbursed smoking cessation pharmacotherapy with behavioral therapy for quitting smokers. We investigate whether inequalities in the use of pharmacotherapy change and, if not, whether this is due to a relatively positive injunctive norm in lower socioeconomic status (SES) groups. A total of 75,415 participants aged ≥15 years from the Dutch Continuous Survey of Smoking Habits, 2009-2012, were considered with the following measures: SES (education/income), injunctive norm (mostly acceptable/neutral/mostly unacceptable), period (2011/all other years), and pharmacotherapy use (yes/no). The proportion of low SES smokers compared with high SES smokers making quit attempts with pharmacotherapy did not differ significantly. The injunctive norm of low SES smokers differed significantly from high SES smokers and nonsmokers of all SES levels. Low income smokers with mostly acceptable injunctive norms were significantly less likely to make quit attempts using pharmacotherapy than those with a neutral or less accepting injunctive norm. The significantly lower use of pharmacotherapy in quit attempts in low income smokers with a positive injunctive norm toward smoking may partly underlie the lack of uptake of reimbursed pharmacotherapy in low SES smokers.

Smoking cessation behavioural therapy in disadvantaged neighbourhoods: an explorative analysis of recruitment channels.

BACKGROUND: The optimum channel(s) used to recruit smokers living in disadvantaged neighbourhoods for smoking cessation behavioural therapy (SCBT) is unknown. This paper examines the channels through which smokers participating in a free, multi-session SCBT programme heard about and were referred to this service in a disadvantaged neighbourhood, and compares participants' characteristics and attendance between channels. METHODS: 109 participants, recruited from free SCBT courses in disadvantaged areas of two cities in the Netherlands, underwent repeated surveys. Participants were asked how they heard about the SCBT and who referred them. Participant characteristics were compared between five channels, including the General Practitioner (GP), a community organisation, word of mouth, another health professional, and media or self-referred. Whether the channels through which people heard about or were referred to the service predicted attendance of ≥4 sessions was investigated with logistic regression analysis. RESULTS: Over a quarter of the participants had no or primary education only, and more than half belonged to ethnic minority populations. Most participants heard through a single channel. More participants heard about (49%) and were referred to (60%) the SCBT by the (GP) than by any other channel. Factors influencing quit success, including psychosocial factors and nicotine dependence, did not differ significantly between channel through which participants heard about the SCBT. No channel significantly predicted attendance. CONCLUSION: The GP was the single most important source to both hear about and be referred to smoking cessation behavioural therapy in a disadvantaged neighbourhood. A majority of participants of low socioeconomic or ethnic minority status heard about the programme through this channel. Neither the channel through which participants heard about or were referred to the therapy influenced attendance. As such, concentrating on the channel which makes use of the existing infrastructure and which is highest yielding, the GP, would be an appropriate strategy if recruitment resources were scarce.

Socioeconomic inequalities in smoking in The Netherlands before and during the Global Financial Crisis: a repeated cross-sectional study.

BACKGROUND: The Global Financial Crisis (GFC) increased levels of financial strain, especially in those of low socioeconomic status (SES). Financial strain can affect smoking behaviour. This study examines socioeconomic inequalities in current smoking and smoking cessation in The Netherlands before and during the Global Financial Crisis (GFC). METHODS: Participants were 66,960 Dutch adults (≥ 18 years) who took part in the annual national Health Survey (2004-2011). Period was dichotomised: 'pre-' and 'during-GFC'. SES measures used were income, education and neighbourhood deprivation. Outcomes were current smoking rates (smokers/total population) and smoking cessation ratios (former smokers/ever smokers). Multilevel logistic regression models controlled for individual characteristics and tested for interaction between period and SES. RESULTS: In both periods, high SES respondents (in all indicators) had lower current smoking levels and higher cessation ratios than those of middle or low SES. Inequalities in current smoking increased significantly in poorly educated adults of 45-64 years of age (Odds Ratio (OR) low educational level compared with high: 2.00[1.79-2.23] compared to pre-GFC 1.67[1.50-1.86], p for interaction = 0.02). Smoking cessation inequalities by income in 18-30 year olds increased with borderline significance during the GFC (OR low income compared to high income: 0.73[0.58-0.91]) compared to pre-GFC (OR: 0.98[0.80-1.20]), p for interaction = 0.051). CONCLUSIONS: Overall, socioeconomic inequalities in current smoking and smoking cessation were unchanged during the GFC. However, current smoking inequalities by education, and smoking cessation inequalities by income, increased in specific age groups. Increased financial strain caused by the crisis may disproportionately affect smoking behaviour in some disadvantaged groups.

Wanting to attend isn't just wanting to quit: why some disadvantaged smokers regularly attend smoking cessation behavioural therapy while others do not: a qualitative study.

BACKGROUND: Attendance of a behavioural support programme facilitates smoking cessation. Disadvantaged smokers have been shown to attend less than their more affluent peers. We need to gain in-depth insight into underlying reasons for differing attendance behaviour in disadvantaged smokers, to better address this issue. This study aims to explore the underlying motivations, barriers and social support of smokers exhibiting different patterns of attendance at a free smoking cessation behavioural support programme in a disadvantaged neighbourhood of The Netherlands. METHODS: In 29 smokers undertaking smoking cessation group therapy or telephone counselling in a disadvantaged neighbourhood, qualitative interviews were completed, coded and analysed. Major themes were motivations, barriers to attend and social support. Motivations and social support were analysed with reference to the self-determination theory. RESULTS: Two distinct patterns of attendance emerged: those who missed up to two sessions ("frequent attenders"), and those who missed more than two sessions ("infrequent attenders"). The groups differed in their motivations to attend, barriers to attendance, and in the level of social support they received. In comparison with the infrequent attenders, frequent attenders more often had intrinsic motivation to attend (e.g. enjoyed attending), and named more self-determined extrinsic motivations to attend, such as commitment to attendance and wanting to quit. Most of those mentioning intrinsic motivation did not mention a desire to quit as a motivation for attendance. No organizational barriers to attendance were mentioned by frequent attenders, such as misunderstandings around details of appointments. Frequent attenders experienced more social support within and outside the course. CONCLUSION: Motivation to attend behavioural support, as distinct from motivation to quit smoking, is an important factor in attendance of smoking cessation courses in disadvantaged areas. Some focus on increasing motivation to attend may help to prevent participants missing sessions.

Plasma phosphorylated-TDP-43 protein levels correlate with brain pathology in frontotemporal lobar degeneration.

In the present study, we have correlated plasma TDP-43 levels, as measured by ELISA, with the presence of TDP-43 pathological changes in the brains of 28 patients with frontotemporal lobar degeneration (FTLD) (14 with FTLD-TDP and 14 with FTLD-tau) and 24 patients with pathologically confirmed AD (8 with, and 16 without, TDP-43 pathological changes). Western blotting revealed full-length TDP-43, including a phosphorylated form, and a phosphorylated C-terminal fragment, in all samples examined. Both ELISA and immunohistochemistry were performed using phospho-dependent and phospho-independent TDP-43 antibodies for detection of phosphorylated and total TDP-43, respectively. Over all 52 cases, plasma levels of TDP-43, and scores of brain TDP-43 pathology, determined using TDP-43 phospho-dependent antibody correlated with the equivalent measure determined using the TDP phospho-independent antibody. In FTLD, but not AD, TDP-43 plasma levels correlated significantly with the pathology score when using the TDP-43 phospho-dependent antibody, but a similar correlation was not seen in either FTLD or AD using the TDP-43 phospho-independent antibody. With the TDP-43 phospho-independent antibody, there were no significant differences in median plasma TDP-43 levels between FTLD, or AD, patients with or without TDP-43 pathology. Using TDP-43 phospho-dependent antibody, median plasma TDP-43 levels were greater in patients with, than in those without, TDP-43 pathology for FTLD patients, though not significantly so, but not for AD patients. Present assays for TDP-43 do not differentiate between FTLD, or AD, patients with or without TDP-43 pathological changes in their brains. However, the levels of phosphorylated TDP-43 in plasma do correlate with the extent of TDP-43 brain pathology in FTLD, and therefore might be a useful surrogate marker for tracking changes in TDP-43 brain pathology during the course of this disease.

A spectroscopic study of some of the peptidyl radicals formed following hydroxyl radical attack on beta-amyloid and alpha-synuclein.

There is clear evidence implicating oxidative stress in the pathology of many neurodegenerative diseases. Reactive oxygen species (ROS) are the primary mediators of oxidative stress, and hydrogen peroxide, a key ROS, is generated during aggregation of the amyloid proteins associated with some of these diseases. Hydrogen peroxide is catalytically converted to the aggressive hydroxyl radical in the presence of Fe(II) and Cu(I), which renders amyloidogenic proteins such as beta-amyloid and alpha-synuclein (implicated in Alzheimer's disease (AD) and Parkinson's disease (PD), respectively) vulnerable to self-inflicted hydroxyl radical attack. Here, we report some of the peptide-derived radicals, detected by electron spin resonance spectroscopy employing sodium 3,5-dibromo-4-nitrosobenzenesulfonate as a spin-trap, following hydroxyl radical attack on Abeta(1-40), alpha-synuclein and some other related peptides. Significantly, we found that sufficient hydrogen peroxide was self-generated during the early stages of aggregation of Abeta(1-40) to produce detectable peptidyl radicals, on addition of Fe(II). Our results support the hypothesis that oxidative damage to Abeta (and surrounding molecules) in the brain in AD could be due, at least in part, to the self-generation of ROS. A similar mechanism could operate in PD and some other "protein conformational" disorders.

A strategy for designing inhibitors of alpha-synuclein aggregation and toxicity as a novel treatment for Parkinson's disease and related disorders.

Convergent biochemical and genetic evidence suggests that the formation of alpha-synuclein (alpha-syn) protein deposits is an important and, probably, seminal step in the development of Parkinson's disease (PD), dementia with Lewy bodies (DLB) and multiple system atrophy (MSA). It has been reported that transgenic animals overexpressing human alpha-syn develop lesions similar to those found in the brain in PD, together with a progressive loss of dopaminergic cells and associated abnormalities of motor function. Inhibiting and/or reversing alpha-syn self-aggregation could, therefore, provide a novel approach to treating the underlying cause of these diseases. We synthesized a library of overlapping 7-mer peptides spanning the entire alpha-syn sequence, and identified amino acid residues 64-100 of alpha-syn as the binding region responsible for its self-association. Modified short peptides containing alpha-syn amino acid sequences from part of this binding region (residues 69-72), named alpha-syn inhibitors (ASI), were found to interact with full-length alpha-syn and block its assembly into both early oligomers and mature amyloid-like fibrils. We also developed a cell-permeable inhibitor of alpha-syn aggregation (ASID), using the polyarginine peptide delivery system. This ASID peptide was able to inhibit the DNA damage induced by Fe(II) in neuronal cells transfected with alpha-syn(A53T), a familial PD-associated mutation. ASI peptides without this delivery system did not reverse levels of Fe(II)-induced DNA damage. Furthermore, the ASID peptide increased (P<0.0005) the number of cells stained positive for Bcl-2, while significantly (P<0.05) decreasing the percentage of cells stained positive for BAX. These short peptides could serve as lead compounds for the design of peptidomimetic drugs to treat PD and related disorders.

Functional interaction between the Bloom's syndrome helicase and the RAD51 paralog, RAD51L3 (RAD51D).

Bloom's syndrome (BS) is a genetic disorder associated with short stature, fertility defects, and a predisposition to the development of cancer. BS cells are characterized by genomic instability; in particular, a high rate of reciprocal exchanges between sister-chromatids and homologous chromosomes. The BS gene product, BLM, is a helicase belonging to the highly conserved RecQ family. BLM is known to form a complex with the RAD51 recombinase, and to act upon DNA intermediates that form during homologous recombination, including D-loops and Holliday junctions. Here, we show that BLM also makes a direct physical association with the RAD51L3 protein (also known as RAD51D), a so-called RAD51 paralog that shows limited sequence similarity to RAD51 itself. This interaction is mediated through the N-terminal domain of BLM. To analyze functional interactions between BLM and RAD51L3, we have purified a heteromeric complex comprising RAD51L3 and a second RAD51 paralog, XRCC2. We show that the RAD51L3-XRCC2 complex stimulates BLM to disrupt synthetic 4-way junctions that model the Holliday junction. We also show that a truncated form of BLM, which retains helicase activity but is unable to bind RAD51L3, is not stimulated by the RAD51L3-XRCC2 complex. Our data indicate that the activity of BLM is modulated through an interaction with the RAD51L3-XRCC2 complex, and that this stimulatory effect on BLM is dependent upon a direct physical association between the BLM and RAD51L3 proteins. We propose that BLM co-operates with RAD51 paralogs during the late stages of homologous recombination processes that serve to restore productive DNA replication at sites of damaged or stalled replication forks.

XRCC3 and Rad51 modulate replication fork progression on damaged vertebrate chromosomes.

The mechanisms by which the progression of eukaryotic replication forks is controlled after DNA damage are unclear. We have found that fork progression is slowed by cisplatin or UV treatment in intact vertebrate cells and in replication assays in vitro. Fork slowing is reduced or absent in irs1SF CHO cells and XRCC3(-/-) chicken DT40 cells, indicating that fork slowing is an active process that requires the homologous recombination protein XRCC3. The addition of purified human Rad51C-XRCC3 complex restores fork slowing in permeabilized XRCC3(-/-) cells. Moreover, the requirement for XRCC3 for fork slowing can be circumvented by addition of human Rad51. These data demonstrate that the recombination proteins XRCC3 and Rad51 cooperatively modulate the progression of replication forks on damaged vertebrate chromosomes.