Comparison of Proteomic Assessment Methods in Multiple Cohort Studies

Novel proteomics platforms, such as the aptamer‐based SOMAscan platform, can quantify large numbers of proteins efficiently and cost‐effectively and are rapidly growing in popularity. However, comparisons to conventional immunoassays remain underexplored, leaving investigators unsure when cross‐assay comparisons are appropriate. The correlation of results from immunoassays with relative protein quantification is explored by SOMAscan. For 63 proteins assessed in two chronic obstructive pulmonary disease (COPD) cohorts, subpopulations and intermediate outcome measures in COPD Study (SPIROMICS), and COPDGene, using myriad rules based medicine multiplex immunoassays and SOMAscan, Spearman correlation coefficients range from ?0.13 to 0.97, with a median correlation coefficient of ≈0.5 and consistent results across cohorts. A similar range is observed for immunoassays in the population‐based Multi‐Ethnic Study of Atherosclerosis and for other assays in COPDGene and SPIROMICS. Comparisons of relative quantification from the antibody‐based Olink platform and SOMAscan in a small cohort of myocardial infarction patients also show a wide correlation range. Finally, cis pQTL data, mass spectrometry aptamer confirmation, and other publicly available data are integrated to assess relationships with observed correlations. Correlation between proteomics assays shows a wide range and should be carefully considered when comparing and meta‐analyzing proteomics data across assays and studies.     

Isolation of primers for candidate genes for mechano-sensing in five Neotropical tree species

Mechanical signals have an impact on plant development. Tropical rainforest trees display large variability for life–history traits related to biomechanics and therefore are a unique study system to better understand biomechanical trait variability from an evolutionary perspective. From sequences and gene expression data available in model species, we developed specific primers for six candidate genes for mechano-sensing in five tropical species. Most of the gene sequences were polymorphic in most species.     

Microalgal cryo-preservation using dimethyl sulfoxide (Me2SO) coupled with two freezing protocols: Influence on the fatty acid profile

Procedures for determining the optimal pre-freezing protocol for cryo-preservation of microalgae are discussed. Three algal species were used (Chlorella vulgaris, Isochrysis galbana and Dunaliella salina) and cryo-stored using two different methods: the slow cooling and the fast freezing. In the slow cooling, each algae batch was treated with or without cryo-protectant (dimethyl sulfoxide: Me₂SO 5% v/v). After 20 min at 4 °C, the midi-straws were filled and cooled slowly (1.5 °C min⁻¹) to −140 °C, by a programmable freezer (Digitcool—IMV), before putting them directly into liquid nitrogen. Fast freezing was performed with 10% or 15% Me₂SO prior to plunging into liquid nitrogen. The three algal species followed the same re-growth pattern as that of the controls. The post-thawed viability with Me₂SO was good for all the selected algae (C. vulgaris >95%, I. galbana and D. salina >70% of the control), applying the slow cooling. The post-thawed viability without Me₂SO was 60% for I. galbana, 52% for D. salina and 33% for C. vulgaris. Fast freezing was not suitable for cryo-storage of I. galbana but gave good post-thawing viability for D. salina (70%). The decrease in fatty acid content of the cryo-stored algae was influenced by the temperature. The rapid decrease in temperature induced by fast freezing can explain the low level of fatty acid content of the three cryo-stored algae. Fatty acid profiles show that the nutritional values of the three cryo-stored micro-algae were not significantly affected especially when treated with slow cooling protocols.     

Identification of noncytotoxic and IL-10-producing CD8+AT2R+ T cell population in response to ischemic heart injury

Emerging evidence suggests a cardioprotective role of the angiotensin AT2R, albeit the underlying cellular mechanisms are not well understood. We aimed in this article to elucidate a potential role of cardiac angiotensin AT2R in regulating cellular immune response to ischemic heart injury. Seven days after myocardial infarction in rats, double-immunofluorescence staining showed that AT2R was detected in a fraction of CD8(+) T cells infiltrating in the peri-infarct myocardium. We developed a method that allowed the isolation of myocardial infiltrating CD8(+)AT2R(+) T cells using modified MACS, and further characterization and purification with flow cytometry. Although the CD8(+)AT2R(-) T cells exhibited potent cytotoxicity to both adult and fetal cardiomyocytes (CMs), the CD8(+)AT2R(+) T cells were noncytotoxic to these CMs. The CD8(+)AT2R(+) T cells were characterized by upregulated IL-10 and downregulated IL-2 and INF-γ expression when compared with CD8(+)AT2R(-) T cells. We further showed that IL-10 gene expression was enhanced in CD8(+) T cells on in vitro AT2R stimulation. Importantly, in vivo AT2R activation engendered an increment of CD8(+)AT2R(+) T cells and IL-10 production in the ischemic myocardium. In addition, intramyocardial transplantation of CD8(+)AT2R(+) T cells (versus CD8(+)AT2R(-)) led to reduced ischemic heart injury. Moreover, the CD8(+)AT2R(+) T cell population was also demonstrated in human peripheral blood. Thus, we have defined the cardioprotective CD8(+)AT2R(+) T cell population, which increases during ischemic heart injury and contributes to maintaining CM viability and providing IL-10, hence revealing an AT2R-mediated cellular mechanism in modulating adaptive immune response in the heart.     

Interactions d’une restriction calorique avec les effets du Nickel sur la reproduction chez le rat

Human epidemiological studies have demonstrated signs of a reduction, since 1960, of several parameters of the sperm count with an increase of certain male genital tract diseases. The increasing contamination of the environment by chemical compounds appears to be an aetiological factor. Various authors have also proposed the hypothesis that caloric restriction has a beneficial effect on health or longevity. This study was deisgned to compare the effects of nickel on the reproductive functions of rats fed either daily or every second day, in order to evaluate the possible beneficial effects of caloric restriction on rat fertility. This study was conducted with male and female Wistar rats, fed either daily (N), or every second day: intermittent fasting (F). After one month of this treatment, (N) and (F) rats were divided into 2 groups: one group received tap water (NO and FO groups), and the other received the same water enriched with nickel chloride (100 mg/L, NNi and FNi groups). Intermittent fasting was continued in parallel with nickel treatment with for 2, 4, 10, 16, 30 and 60 days. To study malonic dialdehyde (MDA) levels, nickel was administered by intraperitoneal injection at the dosage of 4 mg NiCl₂/kg of body weight for 1, 3, 5 and 10 days. Our results show that nickel induces atrophy of the seminiferous tubules with a reduction of the sperm count and a reduction of serum testosterone levels. A reduction of the number of ovarian follicles was observed in females. Intermittent fasting induced the same types of disturbances with more marked reductions of the number of mobile spermatozoa and serum festosterone levels than those observed after exposure to nickel. The combination of the two factors, fasting and nickel, did not amplify these effects. Analysis of intergroup crosses showed that the pregnancy rate and especially the mean number of implantations were decreased in rats exposed to nickel and/or submitted to intermittent fasting. The lowest pregnancy rate (55%) was observed in (NNi) females crossed with (NO) control males. The smallest number of implantations was observed in (NO) control females crossed with (NNi) males. Nickel did not induce any additional reduction of fertility in rats submitted to intermittent fasting. MDA assays showed that nickel induces lipid peroxidation in ovarian and uterine tissues. However, the relative increase of the MDA level was lower in FNi than NNi rats, i.e. when nickel was associated with intermittent fasting. Our results suggest that nickel and intermittent fasting decrease fertility in rats via two different mechanisms whose effects are not additive. When associated with intermittent fasting, nickel becomes non-toxic, as confirmed by montoring of MDA levels. The low-calorie effect of intermittent fasting could be responsible for inhibition of the cytotoxic effects of metallic nickel classified as an oxidative stress.