Neurocalcin Delta Suppression Protects against Spinal Muscular Atrophy in Humans and across Species by Restoring Impaired Endocytosis

This document is the Accepted Manuscript version of the following article: Riessland et al., 'Neurocalcin Delta Suppression Protects against Spinal Muscular Atrophy in Humans and across Species by Restoring Impaired Endocytosis', The American Journal of Human Genetics, Vol. 100 (2): 297-315, first published online 26 January 2017. The final, published version is available online at doi: http://dx.doi.org/10.1016/j.ajhg.2017.01.005 © 2017 American Society of Human Genetics.Homozygous SMN1 loss causes spinal muscular atrophy (SMA), the most common lethal genetic childhood motor neuron disease. SMN1 encodes SMN, a ubiquitous housekeeping protein, which makes the primarily motor neuron-specific phenotype rather unexpected. SMA-affected individuals harbor low SMN expression from one to six SMN2 copies, which is insufficient to functionally compensate for SMN1 loss. However, rarely individuals with homozygous absence of SMN1 and only three to four SMN2 copies are fully asymptomatic, suggesting protection through genetic modifier(s). Previously, we identified plastin 3 (PLS3) overexpression as an SMA protective modifier in humans and showed that SMN deficit impairs endocytosis, which is rescued by elevated PLS3 levels. Here, we identify reduction of the neuronal calcium sensor Neurocalcin delta (NCALD) as a protective SMA modifier in five asymptomatic SMN1-deleted individuals carrying only four SMN2 copies. We demonstrate that NCALD is a Ca(2+)-dependent negative regulator of endocytosis, as NCALD knockdown improves endocytosis in SMA models and ameliorates pharmacologically induced endocytosis defects in zebrafish. Importantly, NCALD knockdown effectively ameliorates SMA-associated pathological defects across species, including worm, zebrafish, and mouse. In conclusion, our study identifies a previously unknown protective SMA modifier in humans, demonstrates modifier impact in three different SMA animal models, and suggests a potential combinatorial therapeutic strategy to efficiently treat SMA. Since both protective modifiers restore endocytosis, our results confirm that endocytosis is a major cellular mechanism perturbed in SMA and emphasize the power of protective modifiers for understanding disease mechanism and developing therapies.Peer reviewedFinal Accepted Versio

Effects of supplying leucine and methionine to early-lactating cows fed silage-concentrate based diets with a calculated deficiency in leucine and methionine

In a 2 $\times$ 2 factorial approach the productive and metabolic response of 24 multiparous Brown Swiss cows fed rations calculated to be deficient in leucine (0.9-fold of requirements) and methionine (0.8-fold) to supplementation either of one or both of these amino acids were investigated. On a dry matter basis the rations consisted of 29% grass silage, 20% maize silage, 6% hay, and 45% concentrate. Blood plasma amino acid data confirmed the intended difference in metabolic supply of leucine and methionine keeping a low variation in the plasma levels of the other essential amino acids, particularly lysine. Live weight, milk yield as well as content and amount of milk fat were not affected by the treatments. Content and amount of milk protein were significantly reduced relative to initial level without additional methionine. Nutrient digestibility and nitrogen balance remained widely unchanged by the supplementations. Except of plasma aspartate amino transferase, cholesterol, creatinine and ornithine, which responded to methionine, hormones, enzyme activities as well as plasma, urine and milk metabolites were not systematically influenced by leucine and methionine supply. The present results gave clearer indications for a deficiency in methionine than in leucine.Effets de l'apport de leucine et méthionine chez des vaches en début de lactation recevant des rations ensilage-concentré à déficit calculé en leucine et méthionine. Vingt-quatre vaches laitières multipares Brown Swiss ont été affouragées avec des rations calculées pour être déficientes en leucine (0,9 fois du besoin) et méthionine (0,8 fois). Les effets d'une supplémentation de l'un ou des deux acides aminés sur la production et le métabolisme de ces vaches ont été examinés à l'aide d'une approche factorielle 2 $\times$ 2. En matière sèche, les rations étaient composées de 29 % d'ensilage d'herbe, 20 % d'ensilage de maïs, 6 % de foin et 45 % de concentrés. Comme prévu, les analyses des acides aminés dans le plasma sanguin ont confirmé une disponibilité métabolique différente de la leucine et de la méthionine, alors que les autres acides aminés essentiels n'ont montré que peu de variation, en particulier la lysine. Le poids vif, la production et la composition du lait, ainsi que la quantité de ses matières grasses n'ont pas été affectés par les traitements. Sans méthionine supplémentaire la teneur et la quantité de protéines dans le lait ont diminué significativement par rapport au niveau initial. La digestibilité des nutriments et le bilan azoté sont restés inchangés malgré les supplémentations. Les taux hormonaux et les activités enzymatiques sanguins, ainsi que les métabolites du sang, de l'urine et du lait le plus souvent n'ont pas répondu clairement à l'adjonction de leucine et méthionine. Les résultats suggèrent l'existence d'une déficience en methionine plutôt qu'en leucine

Chloromethane Degradation in Soils: A Combined Microbial and Two-Dimensional Stable Isotope Approach

German Science Foundation (DFG KE 884/10-1 ; ANR-14-CE35-0005-01) ; French National Research Agency (DFG KE 884/10-1 ; ANR-14-CE35-0005-01)International audienceChloromethane (CH3Cl, methyl chloride) is the most abundant volatile halocarbon in the atmosphere and involved in stratospheric ozone depletion. The global CH3Cl budget, and especially the CH3Cl sink from microbial degradation in soil, still involves large uncertainties. These may potentially be resolved by a combination of stable isotope analysis and bacterial diversity studies. We determined the stable isotope fractionation of CH3Cl hydrogen and carbon and investigated bacterial diversity during CH3Cl degradation in three soils with different properties (forest, grassland, and agricultural soils) and at different temperatures and headspace mixing ratios of CH3Cl. The extent of chloromethane degradation decreased in the order forest > grassland > agricultural soil. Rates ranged from 0.7 to 2.5 μg g−1 dry wt. d−1 for forest soil, from 0.1 to 0.9 μg g−1 dry wt. d−1 for grassland soil, and from 0.1 to 0.4 μg g−1 dry wt. d−1 for agricultural soil and increased with increasing temperature and CH3Cl supplementation. The measured mean stable hydrogen enrichment factor of CH3Cl of −50 ± 13‰ was unaffected by temperature, mixing ratio, or soil type. In contrast, the stable carbon enrichment factor depended on CH3Cl degradation rates and ranged from −38 to −11‰. Bacterial community composition correlated with soil properties was independent from CH3Cl degradation or isotope enrichment. Nevertheless, increased abundance after CH3Cl incubation was observed in 21 bacterial operational taxonomical units (OTUs at the 97% 16S RNA sequence identity level). This suggests that some of these bacterial taxa, although not previously associated with CH3Cl degradation, may play a role in the microbial CH3Cl sink in soil

Community assembly during secondary forest succession in a Chinese subtropical forest

Subtropical broad-leaved forests in southeastern China support a high diversity of woody plants. Using a comparative study design with 30 × 30 m plots (n = 27) from five successional stages (1 m in height in each plot and counted all woody recruits (bank of all seedlings ⋜ 1 m in height) in each central 10 × 10 m quadrant of each plot. In addition, we measured a number of environmental variables (elevation, slope, aspect, soil moisture, pH, C, N, and C/N ratio) and biotic structural variables (height and cover of layers). Adult species richness varied from 25 to 69 species per plot, and in total 148 woody species from 46 families were recorded. There was a clear successional gradient in species composition as revealed by nonmetric multidimensional scaling (NMDS), but only a poor differentiation of different successional stages with respect to particular species. Adult richness per 100 individuals (rarefaction method) increased with successional stage. None of the measured abiotic variables were significantly correlated with adult species richness. We found no evidence that rare species were responsible for the increasing adult species richness, as richness of rare species among both adults and recruits was independent of the successional stage. Furthermore, the similarity between established adults and recruits did not increase with successional stage. There was a constant number of recruit species and also of exclusive recruit species, i.e., those that had not been present as adult individuals, across all successional stages, suggesting a continuous random immigration over time