Anti‐inflammaging effects of human alpha‐1 antitrypsin

Inflammaging plays an important role in most age‐related diseases. However, the mechanism of inflammaging is largely unknown, and therapeutic control of inflammaging is challenging. Human alpha‐1 antitrypsin (hAAT) has immune‐regulatory, anti‐inflammatory, and cytoprotective properties as demonstrated in several disease models including type 1 diabetes, arthritis, lupus, osteoporosis, and stroke. To test the potential anti‐inflammaging effect of hAAT, we generated transgenic Drosophila lines expressing hAAT. Surprisingly, the lifespan of hAAT‐expressing lines was significantly longer than that of genetically matched controls. To understand the mechanism underlying the anti‐aging effect of hAAT, we monitored the expression of aging‐associated genes and found that aging‐induced expressions of Relish (NF‐?B orthologue) and Diptericin were significantly lower in hAAT lines than in control lines. RNA‐seq analysis revealed that innate immunity genes regulated by NF‐kB were significantly and specifically inhibited in hAAT transgenic Drosophila lines. To confirm this anti‐inflammaging effect in human cells, we treated X‐ray‐induced senescence cells with hAAT and showed that hAAT treatment significantly decreased the expression and maturation of IL‐6 and IL‐8, two major factors of senescence‐associated secretory phenotype. Consistent with results from Drosophila,RNA‐seq analysis also showed that hAAT treatment significantly inhibited inflammation related genes and pathways. Together, our results demonstrated that hAAT significantly inhibited inflammaging in both Drosophila and human cell models. As hAAT is a FDA‐approved drug with a confirmed safety profile, this novel therapeutic potential may make hAAT a promising candidate to combat aging and aging‐related diseases.     

A BioBrick compatible strategy for genetic modification of plants

ABSTRACT: BACKGROUND: Plant biotechnology can be leveraged to produce food, fuel, medicine, and materials. Standardized methods advocated by the synthetic biology community can accelerate the plant design cycle, ultimately making plant engineering more widely accessible to bioengineers who can contribute diverse creative input to the design process. RESULTS: This paper presents work done largely by undergraduate students participating in the 2010 International Genetically Engineered Machines (iGEM) competition. Described here is a framework for engineering the model plant Arabidopsis thaliana with standardized, BioBrick compatible vectors and parts available through the Registry of Standard Biological Parts (www.partsregistry.org). This system was used to engineer a proof-of-concept plant that exogenously expresses the taste-inverting protein miraculin. CONCLUSIONS: Our work is intended to encourage future iGEM teams and other synthetic biologists to use plants as a genetic chassis. Our workflow simplifies the use of standardized parts in plant systems, allowing the construction and expression of heterologous genes in plants within the timeframe allotted for typical iGEM projects.     

Calorie Restriction-Mediated Replicative Lifespan Extension in Yeast Is Non-Cell Autonomous

In laboratory yeast strains with Sir2 and Fob1 function, wild-type NAD⁺ salvage is required for calorie restriction (CR) to extend replicative lifespan. CR does not significantly alter steady state levels of intracellular NAD⁺ metabolites. However, levels of Sir2 and Pnc1, two enzymes that sequentially convert NAD⁺ to nicotinic acid (NA), are up-regulated during CR. To test whether factors such as NA might be exported by glucose-restricted mother cells to survive later generations, we developed a replicative longevity paradigm in which mother cells are moved after 15 generations on defined media. The experiment reveals that CR mother cells lose the longevity benefit of CR when evacuated from their local environment to fresh CR media. Addition of NA or nicotinamide riboside (NR) allows a moved mother to maintain replicative longevity despite the move. Moreover, conditioned medium from CR-treated cells transmits the longevity benefit of CR to moved mother cells. Evidence suggests the existence of a longevity factor that is dialyzable but is neither NA nor NR, and indicates that Sir2 is not required for the longevity factor to be produced or to act. Data indicate that the benefit of glucose-restriction is transmitted from cell to cell in budding yeast, suggesting that glucose restriction may benefit neighboring cells and not only an individual cell.     

Biophysical models of radiation bystander effects: 1. Spatial effects in three-dimensional tissues

Non-targeted (bystander) effects of ionizing radiation are caused by intercellular signaling; they include production of DNA damage and alterations in cell fate (i.e. apoptosis, differentiation, senescence or proliferation). Biophysical models capable of quantifying these effects may improve cancer risk estimation at radiation doses below the epidemiological detection threshold. Understanding the spatial patterns of bystander responses is important, because it provides estimates of how many bystander cells are affected per irradiated cell. In a first approach to modeling of bystander spatial effects in a three-dimensional artificial tissue, we assume the following: (1) The bystander phenomenon results from signaling molecules (S) that rapidly propagate from irradiated cells and decrease in concentration (exponentially in the case of planar symmetry) as distance increases. (2) These signals can convert cells to a long-lived epigenetically activated state, e.g. a state of oxidative stress; cells in this state are more prone to DNA damage and behavior alterations than normal and therefore exhibit an increased response (R) for many end points (e.g. apoptosis, differentiation, micronucleation). These assumptions are implemented by a mathematical formalism and computational algorithms. The model adequately describes data on bystander responses in the 3D system using a small number of adjustable parameters.     

The crystal structure of human E-cadherin domains 1 and 2, and comparison with other cadherins in the context of adhesion mechanism

Cell adhesion mediated by type I cadherins involves homophilic "trans" interactions that are thought to be brought about by a strand exchange mechanism involving the N-terminal extracellular domain. Here, we present the high-resolution crystal structure of the N-terminal two domains of human E-cadherin. Comparison of this structure with other type I cadherin structures reveals features that are likely to be critical to facilitate dimerization by strand exchange as well as dimer flexibility. We integrate this structural knowledge to provide a model for type I cadherin adhesive interactions. Intra-molecular docking of the conserved N-terminal "adhesion arm" into the acceptor pocket in monomeric E-cadherin appears largely identical to inter-molecular docking of the adhesion arm in adhesive trans dimers. A strained conformation of the adhesion arm in the monomer, however, may create an equilibrium between "open" and "closed" forms that primes the cadherin for formation of adhesive interactions, which are then stabilized by additional dimer-specific contacts. By contrast, in type II cadherins, strain in the adhesion arm appears absent and a much larger surface area is involved in trans adhesion, which may compensate the activation energy required to peel off the intra-molecularly docked arm. It seems that evolution has selected slightly different adhesion mechanisms for type I and type II cadherins.     

How do glial-neuronal interactions fit into current neurotransmitter hypotheses of schizophrenia?

Evidence is accumulating that the exclusive dopamine hypothesis of schizophrenia has to be abandoned. Instead, a more integrative approach combines different neurotransmitter systems, in which glutamatergic, GABAergic and dopaminergic pathways interact. This paradigm shift coincides with the recognition that, while typical and modern atypical antipsychotic drugs have efficiently controlled the dramatic psychotic symptoms of schizophrenia, their impact on negative and cognitive symptoms is negligible. Indeed, cognitive decline is now believed to represent the core of schizophrenic morbidity and in this context, impairment of glutamate and more specifically NMDA function is of major importance. Given that astrocytes are important in controlling glutamate homeostasis, it is necessary to assign a significant role to glial-neuronal interactions in the pathophysiology of schizophrenia. Indeed, recent data from several animal and human studies corroborate this notion. This review outlines current neurotransmitter hypotheses and evidence for glial impairment in schizophrenia. Furthermore, findings from recent studies of (13)C nuclear magnetic resonance spectroscopy in experimental models of schizophrenia and NMDA hypofunction are presented and their implications for future research on glial-neuronal interactions discussed.     

Development of SPECT imaging agents for the norepinephrine transporters: [123I]INER

A series of reboxetine analogs was synthesized and evaluated for in vitro binding as racemic mixtures. The best candidate (INER) was synthesized as the optically pure (S,S) enantiomer, labeled with iodine-123 and its in vivo binding determined by SPECT imaging in baboons. The in vivo specificity, selectivity, and kinetics of [123I]INER make it a promising agent for imaging NET in vivo by noninvasive SPECT imaging.     

Genetic regulation of T regulatory, CD4, and CD8 cell numbers by the arthritis severity loci Cia5a, Cia5d, and the MHC/Cia1 in the rat

T cells have a central role in the pathogenesis of autoimmune arthritis, and several abnormalities in T cell homeostasis have been described in rheumatoid arthritis (RA). We hypothesized that T cell phenotypes, including frequencies of different subsets of T regulatory (Treg) cells and in vitro functional responses could be genetically determined. Furthermore, we considered that the genetic contribution would be accounted for by one of the arthritis regulatory quantitative trait loci (QTL), thus providing novel clues to gene mode of action. T cells were isolated from thymus, peripheral blood, and spleen from DA (arthritis-susceptible) and ACI and F344 (arthritis-resistant) strains and from F344.DA(Cia1), DA.F344(Cia5a), and DA.F344(Cia5d) rats congenic for arthritis QTL. T cell subpopulations differed significantly between DA, F344, and ACI. DA rats had an increased frequency of CD4(+) cells, and a reduction in CD8(+) and CD4(+)CD45RC(|o) Treg cells, compared with F344. The differences in CD4/CD8 and CD4(+)CD45RC(|o) Treg cells were accounted for by Cia5a. DA rats also had a reduced frequency of CD8(+)CD45RC(|o) CD25(+) Treg cells compared with F344, and that difference was explained by Cia5d. DA rats also had a significantly lower frequency of CD4(+)CD25(+) and CD8(+)CD25(+) thymocytes, and of peripheral blood CD8(+)CD45RC(|o) Treg cells, compared with F344 rats, and that difference was accounted for by the MHC. This is the first identification of arthritis severity QTL regulating numbers of CD4(+)CD45RC(|o) (Cia5a) and CD8(+)CD45RC(|o) CD25(+) (Cia5d) Treg cells. The MHC effect on CD8(+) Treg cells and CD25(+) thymocytes raises a novel potential explanation for its association with arthritis.     

Nuclear genome size in Selaginella.

Estimates of nuclear genome size for 9 Selaginella species were obtained using flow cytometry, and measurements for 7 of these species are reported for the first time. Estimates range from 0.086 to 0.112 pg per holoploid genome (84-110 Mb). The data presented here agree with the previously published flow cytometric results for S. moellendorffii. Within the 9 species sampled here, chromosome number varies from 2n = 16 to 2n = 27. Nuclear genome size appears to be strongly correlated with chromosome number (Spearman's rank correlation; p = 0.00003725). Cultivated S. moellendorffii lacks sexual reproduction--manifest by the production of abortive megasporangia. Flow cytometric data generated from a herbarium specimen of a fertile wild-collected S. moellendorffii are virtually indistinguishable from the data generated from fresh material (0.088 vs. 0.089 pg/1C). Therefore, the limited fertility observed in cultivated plants is probably not the result of abnormal chromosome number (e.g., induced by interspecific hybridization).     

CD1 antigen presentation: how it works

The classic concept of self-non-self discrimination by the immune system focused on the recognition of fragments from proteins presented by classical MHC molecules. However, the discovery of MHC-class-I-like CD1 antigen-presentation molecules now explains how the immune system also recognizes the abundant and diverse universe of lipid-containing antigens. The CD1 molecules bind and present amphipathic lipid antigens for recognition by T-cell receptors. Here, we outline the recent advances in our understanding of how the processes of CD1 assembly, trafficking, lipid-antigen binding and T-cell activation are achieved and the new insights into how lipid antigens differentially elicit CD1-restricted innate and adaptive T-cell responses.