Genome-wide analysis of a multi-incident family with autosomal-dominant parkinsonism has implicated a locus on chromosomal region 3q26-q28. Linkage and disease segregation is explained by a missense mutation c.3614G>A (p.Arg1205His) in eukaryotic translation initiation factor 4-gamma (EIF4G1). Subsequent sequence and genotype analysis identified EIF4G1 c.1505C>T (p.Ala502Val), c.2056G>T (p.Gly686Cys), c.3490A>C (p.Ser1164Arg), c.3589C>T (p.Arg1197Trp) and c.3614G>A (p.Arg1205His) substitutions in affected subjects with familial parkinsonism and idiopathic Lewy body disease but not in control subjects. Despite different countries of origin, persons with EIF4G1 c.1505C>T (p.Ala502Val) or c.3614G>A (p.Arg1205His) mutations appear to share haplotypes consistent with ancestral founders. eIF4G1 p.Ala502Val and p.Arg1205His disrupt eIF4E or eIF3e binding, although the wild-type protein does not, and render mutant cells more vulnerable to reactive oxidative species. EIF4G1 mutations implicate mRNA translation initiation in familial parkinsonism and highlight a convergent pathway for monogenic, toxin and perhaps virally-induced Parkinson disease.

No abstract

No abstract

Genomic multiplication of the alpha-synuclein gene (SNCA) locus is one cause of familial Parkinson disease (PD). We performed detailed genomic, SNCA expression level, clinical, neuropsychological and functional imaging analyses of a parkinsonian kindred with a known duplication of the SNCA locus. We demonstrated that the duplication spanned 4.928 Mb (encompassing 31 known and putative genes) and was the largest to have been described at this locus. The presence of several repetitive long interspersed nuclear elements (LINEs) flanking the potential break area suggested that the duplication resulted from a genomic recombination between LINEs. We sequenced the break junction and confirmed the involvement of L1PA2 and L1PA4 in a non-allelic, homologous recombination. An analysis of mRNA levels in immortalized lymphoblastoid cells and peripheral blood mononuclear cells showed SNCA overexpression in subjects with the duplication, as well as overexpression of 13 other genes highlighting the usefulness of such cell models to study this duplication. Interestingly, abnormal tracer uptake in DaTSCAN ® imaging correlated with the severity of the clinical symptoms. Our detailed genomic analysis and clinical exploration enabled us to specify the genotype-phenotype relationship, identify a case of presymptomatic PD and gain insight into the role of LINEs in SNCA locus duplication.

The aim of this study was to adapt the Comet assay in spermatozoa of the marine prawn Palaemon serratus to use it as a marker of sperm quality. Indeed, due to the characteristics of their spermatozoa, the measurement of DNA integrity is one of the few markers which can be transferred to crustaceans to assess the quality of their semen. In the first step, the methods of collecting and maintaining spermatozoa were optimized. Cell survival was estimated during kinetics of preservation (i.e. 1, 2, 4 and 8 h) in various suspension media to define artificial seawater (ASW) as optimal. Several methods in the releasing of spermatozoa from the spermatophore of prawns were estimated with regard to their incidence both on the efficiency of extraction and the survival of cells. Pipetting up and down turned out to be the most successful and the least invasive technique. Secondly, the transfer of Comet assay was optimized by studying various times in both cell lysis (i.e. 1, 6, 18 h) and DNA denaturation (i.e. 15, 30 and 45 min), after in vitro exposure of spermatozoa to an H2O2 gradient as model genotoxicant. Results revealed that a minimum of 1 h in cell lysis and 15 min of DNA denaturation were sufficient to obtain valuable results, linked with a low compaction of DNA in spermatozoa of Palaemon sp. Finally, the sensitivity of P. serratus spermatozoa was assessed after in vitro exposures to model genotoxicants displaying various modes of interaction with DNA (i.e. UV-C, 13.3-79.5 J m; HO, 5-10 μM and MMS, 0.5-5 mM) and some environmental contaminants known or suspected to be genotoxic (i.e. cadmium and diuron, 0.015-1.5 μg L; carbamazepine, 0.1-10 μg L) for invertebrates. The low variability of the baseline level of DNA strand breaks recorded in controls highlighted the robustness of the method. P. serratus spermatozoa displayed significant DNA damage from the lowest doses tested for all model genotoxicants, but conversely, no genotoxic effect of tested environmental contaminants was observed. These results, which are discussed according to the protocol tested in the present study and the comparison with literature data, could suggest a difference in the response or sensitivity of spermatozoa to environmental genotoxicity between invertebrate species, and therefore the interest of Palaemonidae prawns in ecogenotoxicology. In conclusion, the present study underlines the potential of the Comet assay as a marker to assess the contamination impact on the sperm quality in Palaemonidae prawns in view to a potential application for in situ biomonitoring surveys.

In teleosts, as in mammals, the immune system is tightly regulated by sexual steroid hormones, such as oestrogens. We investigated the effects of 17β-oestradiol on the expression of several genes related to T cell development and resulting T cell subpopulations in sea bass, Dicentrarchus labrax, for a primary lymphoid organ, the thymus, and two secondary lymphoid organs, the head-kidney and the spleen. In parallel, the oxidative burst capacity was assessed in leucocytes of the secondary lymphoid organs. Apoptosis- and proliferation-related genes, indicative of B and T cell clonal selection and lymphoid progenitor activity, were not affected by elevated oestrogen-levels. Sex-related oestrogen-responsiveness in T cell and antigen-presenting cell markers was observed, the expression of which was differentially induced by oestrogen-exposure in the three lymphoid organs. Remarkably, in the spleen, oestrogen increased regulatory T cell-related gene expression was associated with a decrease in oxidative burst capacity. To the best of our knowledge, this study indicates for the first time that physiological levels of oestrogen are likely to promote immune tolerance by modulating thymic function (i.e., T cell development and output) and peripheral T cells in teleosts, similar to previously reported oestrogenic effects in mammals.

In a previous study, the Comet assay was optimized for Palaemon serratus prawns in order to propose a biomarker for sperm quality in this species. However, better knowledge of its basal level and its natural variability, related to intrinsic biotic and environmental abiotic factors, is required before any relevant use of this biomarker in the field. To fulfill this goal, the present study proceeded in three steps: (i) the temporal variability of DNA integrity was followed monthly in a reference population over a 2-year period, (ii) the correlation between the main intrinsic biotic (i.e. size, weight and molting stage) and abiotic factors (i.e. water temperature) were recorded in the field, and the basal DNA integrity was assessed in order to scrutinize any confounding influence of factors unrelated to toxic response, (iii) the baseline level was used to discriminate biomarker response among different stations displaying contrasting contamination levels. The results of the two-year monitoring in the reference population revealed no correlation between the levels of spermatozoa DNA damage and temperature, body size, weight or molting stage. Only a slight variability between monthly samplings was detected. On the basis of these field-collected data, we defined a reference distribution (i.e. 52.6 ± 5.6 A.U) with a threshold value (i.e. 61.7 A.U). Finally, this threshold value proved its relevance to discriminate among stations with contrasting pollution levels around the Seine Bay. Indeed, the results suggest significant DNA damage in populations nearest the Seine estuary, a major source of contaminants in the Bay, and a lower effect in populations further away from the estuary. The overall conclusion was that the Comet assay on P. serratus spermatozoa could be a useful tool for the monitoring of the toxicological print within sperm and main globally the contamination exposure of crustaceans in marine waters.

An increasing body of evidence suggests that sex steroids play an important role in the development and regulation of vertebrate immune defense. Therefore, compounds with estrogenic activity may influence the immune system via receptor-mediated pathways. The presence of estrogen receptors in immune cells and organs during the early stages of development may indicate that female steroid hormones are involved in the maturation of the fish immune system. This is of particular importance, as some marine fish are probably exposed to sources of exogenous estrogens while they reside in their estuarine nursery grounds. In this study, the influence of 17β-estradiol (E2) on estrogen receptor and cytokine gene expression was assessed in juvenile sea bass (Dicentrarchus labrax) together with characterization of the head kidney leukocyte populations and corresponding phagocytic activity during organ regionalization from 98 to 239 dph. E2 exposure, beginning at 90 dph resulted in indirect and delayed modifications of interleukin 1β and estrogen receptor α gene expression, which may affect B-lymphocyte proliferation in the sea bass head kidney. The E2 treatment of 120 dph fish led to an increase in estrogen receptor β2 and a decrease in transforming growth factor β1 gene expression, which coincided with decreased phagocytic activity of head kidney lymphocytes and monocytes/macrophages. Additionally, these changes were observed during developmental periods described as critical phases for B-lymphocyte development in mammals. Consequently, exogenous estrogens have the potential to modify the innate immune response in juvenile sea bass and to exert detrimental effects on head kidney development. Copyright © 2015 John Wiley & Sons, Ltd.