Protein signatures of centenarians and their offspring suggest centenarians age slower than other humans

Using samples from the New England Centenarian Study (NECS), we sought to characterize the serum proteome of 77 centenarians, 82 centenarians'' offspring, and 65 age‐matched controls of the offspring (mean ages: 105, 80, and 79 years). We identified 1312 proteins that significantly differ between centenarians and their offspring and controls (FDR < 1%), and two different protein signatures that predict longer survival in centenarians and in younger people. By comparing the centenarian signature with 2 independent proteomic studies of aging, we replicated the association of 484 proteins of aging and we identified two serum protein signatures that are specific of extreme old age. The data suggest that centenarians acquire similar aging signatures as seen in younger cohorts that have short survival periods, suggesting that they do not escape normal aging markers, but rather acquire them much later than usual. For example, centenarian signatures are significantly enriched for senescence‐associated secretory phenotypes, consistent with those seen with younger aged individuals, and from this finding, we provide a new list of serum proteins that can be used to measure cellular senescence. Protein co‐expression network analysis suggests that a small number of biological drivers may regulate aging and extreme longevity, and that changes in gene regulation may be important to reach extreme old age. This centenarian study thus provides additional signatures that can be used to measure aging and provides specific circulating biomarkers of healthy aging and longevity, suggesting potential mechanisms that could help prolong health and support longevity.     

Staphylococcus aureus requires cardiolipin for survival under conditions of high salinity

Background  

The ability of staphylococci to grow in a wide range of salt concentrations is well documented. In this study, we aimed to clarify the role of cardiolipin (CL) in the adaptation of Staphylococcus aureus to high salinity.     

Physical activity attenuates the influence of FTO variants on obesity risk: a meta-analysis of 218,166 adults and 19,268 children

Background

The FTO gene harbors the strongest known susceptibility locus for obesity. While many individual studies have suggested that physical activity (PA) may attenuate the effect of FTO on obesity risk, other studies have not been able to confirm this interaction. To confirm or refute unambiguously whether PA attenuates the association of FTO with obesity risk, we meta-analyzed data from 45 studies of adults (n = 218,166) and nine studies of children and adolescents (n = 19,268).

Methods and Findings

All studies identified to have data on the FTO rs9939609 variant (or any proxy [r ²>0.8]) and PA were invited to participate, regardless of ethnicity or age of the participants. PA was standardized by categorizing it into a dichotomous variable (physically inactive versus active) in each study. Overall, 25% of adults and 13% of children were categorized as inactive. Interaction analyses were performed within each study by including the FTO×PA interaction term in an additive model, adjusting for age and sex. Subsequently, random effects meta-analysis was used to pool the interaction terms. In adults, the minor (A−) allele of rs9939609 increased the odds of obesity by 1.23-fold/allele (95% CI 1.20–1.26), but PA attenuated this effect (p _interaction  = 0.001). More specifically, the minor allele of rs9939609 increased the odds of obesity less in the physically active group (odds ratio  = 1.22/allele, 95% CI 1.19–1.25) than in the inactive group (odds ratio  = 1.30/allele, 95% CI 1.24–1.36). No such interaction was found in children and adolescents.

Conclusions

The association of the FTO risk allele with the odds of obesity is attenuated by 27% in physically active adults, highlighting the importance of PA in particular in those genetically predisposed to obesity. Please see later in the article for the Editors'' Summary     

Does the environment around the H-cluster allow coordination of the pendant amine to the catalytic iron center in [FeFe] hydrogenases? Answers from theory

[FeFe] hydrogenases are H₂-evolving enzymes that feature a diiron cluster in their active site (the [2Fe]_H cluster). One of the iron atoms has a vacant coordination site that directly interacts with H₂, thus favoring its splitting in cooperation with the secondary amine group of a neighboring, flexible azadithiolate ligand. The vacant site is also the primary target of the inhibitor O₂. The [2Fe]_H cluster can span various redox states. The active-ready form (H_ox) attains the Fe^IIFe^I state. States more oxidized than H_ox were shown to be inactive and/or resistant to O₂. In this work, we used density functional theory to evaluate whether azadithiolate-to-iron coordination is involved in oxidative inhibition and protection against O₂, a hypothesis supported by recent results on biomimetic compounds. Our study shows that Fe–N(azadithiolate) bond formation is favored for an Fe^IIFe^II active-site model which disregards explicit treatment of the surrounding protein matrix, in line with the case of the corresponding Fe^IIFe^II synthetic system. However, the study of density functional theory models with explicit inclusion of the amino acid environment around the [2Fe]_H cluster indicates that the protein matrix prevents the formation of such a bond. Our results suggest that mechanisms other than the binding of the azadithiolate nitrogen protect the active site from oxygen in the so-called H _ox ^inact state.     

Separation of Soybean Sterols by Florisil Chromatography and Characterization of Acylated Steryl Glucoside

Florisil column chromatography was demonstrated to be effective in differentiation between different forms of sterols. Sterols of ground soybeans are in four forms, free, ester, and free and acylated glucosides, as analyzed on acetone extracts. In soybean oil foots, steryl ester is present in negligibly small amount. The acylated steryl glucosides were isolated from oil foots in a crystalline state. A chemical structure, steryl 6-acyl d-glucoside, was assigned to the compound, and its probable identity with the glucosides reported by Lepage is discussed. The acylated glucoside preparation was shown to be heterogeneous in composition, carrying palmitic, stearic, oleic, linoleic and linolenic acids as the main acyl moieties and campesterol, stigmasterol and β-sitosterol as steryl moieties. The presence of the three sterols is common to three other forms of sterols.     

Gastrointestinal digestion and absorption of Pen j 1, a major allergen from Kuruma prawn, Penaeus japonicus

Tropomyosin had been identified as a major allergen in shrimp. The digestion and absorption of tropomyosin (Pen j 1) from kuruma prawn were investigated by ex vivo, in vitro, and in vivo techniques in order to elucidate the relationship between the allergenicity of the allergen and its gastrointestinal behavior. Pen j 1 transported the Caco-2 monolayer in a dose-dependent manner, and also enhanced the permeability of lucifer yellow, a marker of paracellular transportation, at high concentrations of the allergen. Studies with everted sacs revealed that Pen j 1 was rapidly degraded to small peptides (MW<3.5 kDa) and amino acids by intestinal proteases and absorbed from enterocytes. Furthermore, Pen j 1 orally administered to rats tended to remain in the stomach rather than in the small intestine, after which the allergen moved to the epithelial cells. These observations suggest that Pen j 1 may be absorbed via the gastric mucosa prior to its digestion in the intestines.     

Crystal structure of the functional region of Uro-adherence factor A from Staphylococcus saprophyticus reveals participation of the B domain in ligand binding

Staphylococci use cell wall‐anchored proteins as adhesins to attach to host tissues. Staphylococcus saprophyticus, a uropathogenic species, has a unique cell wall‐anchored protein, uro‐adherence factor A (UafA), which shows erythrocyte binding activity. To investigate the mechanism of adhesion by UafA, we determined the crystal structure of the functional region of UafA at 1.5 Å resolution. The structure was composed of three domains, designated as the N2, N3, and B domains, arranged in a triangular relative configuration. Hemagglutination inhibition assay with domain‐truncated mutants indicated that both N and B domains were necessary for erythrocyte binding. Based on these results, a novel manner of ligand binding in which the B domain acts as a functional domain was proposed as the adhesion mechanism of S. saprophyticus.     

Functional characterization of human and cynomolgus monkey cytochrome P450 2E1 enzymes

Cytochrome P450 2E1 (CYP2E1) is an enzyme of major toxicological interest because it metabolizes various drugs, precarcinogens and solvents to reactive metabolites. In this study, human and cynomolgus monkey CYP2E1 cDNAs (humCYP2E1 and monCYP2E1, respectively) were cloned, and the corresponding proteins were heterologously expressed in yeast cells to identify the functions of primate CYP2E1s. The enzymatic properties of CYP2E1 proteins were characterized by kinetic analysis of chlorzoxazone 6-hydroxylation and 4-nitrophenol 2-hydroxylation. humCYP2E1 and monCYP2E1 enzymes showed 94.3% identity in their amino acid sequences. The functional CYP content in yeast cell microsomes expressing humCYP2E1 was 38.4 pmol/mg protein. The level of monCYP2E1 was 42.7% of that of humCYP2E1, although no significant differences were statistically observed. The K(m) values of microsomes from human livers and yeast cells expressing humCYP2E1 for CYP2E1-dependent oxidation were 822 and 627 microM for chlorzoxazone 6-hydroxylation, and 422 and 514 microM for 4-nitrophenol 2-hydroxylation, respectively. The K(m) values of microsomes from cynomolgus monkey livers and yeast cells expressing monCYP2E1 were not significantly different from those of humans in any enzyme source. V(max) and V(max)/K(m) values of human liver microsomes for CYP2E1-dependent oxidation were 909 pmol/min/mg protein and 1250 nl/min/mg protein for chlorzoxazone 6-hydroxylation, and 1250 pmol/min/mg protein and 2990 nl/min/mg protein for 4-nitrophenol 2-hydroxylation, respectively. The kinetic parameter values of cynomolgus monkey livers were comparable to or lower than those of human liver microsomes (49.5-102%). In yeast cell microsomes expressing humCYP2E1, V(max) and V(max)/K(m) values for CYP2E1-dependent oxidation on the basis of CYP holoprotein level were 170 pmol/min/pmol CYP and 272 nl/min/pmol CYP for chlorzoxazone 6-hydroxylation, and 139 pmol/min/pmol CYP and 277 nl/min/pmol CYP for 4-nitrophenol 2-hydroxylation, respectively, and the kinetic parameters of monCYP2E1 exhibited similar values. These findings suggest that human and cynomolgus monkey CYP2E1 enzymes have high homology in their amino acid sequences, and that their enzymatic properties are considerably similar. The information gained in this study should help with in vivo extrapolation and to assess the toxicity of xenobiotics.     

Novel axonal projection from the caudal end of the ventrolateral medulla to the intermediolateral cell column

We used an optical imaging technique to investigate whether axons of neurons in the caudal end of the ventrolateral medulla (CeVLM), as well as axons of neurons in the rostral ventrolateral medulla (RVLM), project to neurons in the intermediolateral cell column (IML) of the spinal cord. Brain stem-spinal cord preparations from neonatal normotensive Wistar-Kyoto and spontaneously hypertensive rats were stained with a voltage-sensitive dye, and responses to electrical stimulation of the IML at the Th2 level were detected as changes in fluorescence intensity with an optical imaging apparatus (MiCAM-01). The results were as follows: 1) depolarizing responses to IML stimulation during low-Ca high-Mg superfusion were detected on the ventral surface of the medulla at the level of the CeVLM, as well as at the level of the RVLM, 2) depolarizing responses were also detected on cross sections at the level of the CeVLM, and they had a latency of 24.0 +/- 5.5 (SD) ms, 3) antidromic action potentials in response to IML stimulation were demonstrated in the CeVLM neurons where optical images were detected, and 4) glutamate application to the CeVLM increased the frequency of excitatory postsynaptic potentials (EPSPs) and induced depolarization of the IML neurons. The optical imaging findings suggested a novel axonal and functional projection from neurons in the CeVLM to the IML. The increase in EPSPs of the IML neurons in response to glutamate application suggests that the CeVLM participates in the regulation of sympathetic nerve activity and blood pressure and may correspond to the caudal pressor area.