Expression analysis of HLA-E and NKG2A and NKG2C receptors points at a role for natural killer function in ankylosing spondylitis

Background. Ankylosing Spondylitis (AS) is a complex chronic inflammatory disease strongly associated with the majority of HLA-B27 alleles. HLA-E are non-classical MHC class I molecules that specifically interact with the natural killer receptors NKG2A (inhibitory) and NKG2C (activating), and have been recently proposed to be involved in AS pathogenesis. Objectives: To analyze the expression of HLA-E and the CD94/NKG2 pair of receptors in HLA-B27 positive AS patients and healthy controls (HC) bearing the AS-associated, B*2705 and the non-AS-associated, B*2709 allele. Methods: The level of surface expression of HLA-E molecules on CD14 positive peripheral blood mononuclear cell was evaluated in 21 HLA-B*2705 patients with AS, 12 HLA-B*2705 HC, 12 HLA-B*2709 HC and 6 HLA-B27 negative HC, using the monoclonal antibody MEM-E/08 by quantitative cytofluorimetric analysis. The percentage and density of expression of HLA-E ligands NKG2A and NKG2C were also measured on CD3-CD56+ NK cells. Results. HLA-E expression in CD14 positive cells was significantly higher in AS patients (587.0 IQR 424-830) compared to B*2705 HC (389 IQR 251.3-440.5, p=0.0007), B*2709 HC (294.5 IQR 209.5-422, p=0.0004) and HLA-B27 negative HC (380 IQR 197.3-515.0, p=0.01). A higher number of NK cells expressing NKG2A compared to NKG2C was found in all cohort analysed as well as a higher cell surface density. Conclusion: The higher surface level of HLA-E molecules in AS patients compared to HC, concurrently with a prevalent expression of NKG2A, suggests that the crosstalk between these two molecules might play a role in AS pathogenesis accounting for the previously reported association between HLA-E and AS

The Surprising Story of Fusicoccin: A Wilt-Inducing Phytotoxin, a Tool in Plant Physiology and a 14-3-3-Targeted Drug

Fusicoccin is the alpha glucoside of a carbotricyclic diterpene, produced by the fungus Phomopsis amygdali (previously classified as Fusicoccum amygdali), the causal agent of almond and peach canker disease. A great interest in this molecule started when it was discovered that it brought about an irreversible stomata opening of higher plants, thereby inducing the wilting of their leaves. Since then, several studies were carried out to elucidate its biological activity, biosynthesis, structure, structure-activity relationships and mode of action. After sixty years of research and more than 1800 published articles, FC is still the most studied phytotoxin and one of the few whose mechanism of action has been elucidated in detail. The ability of FC to stimulate several fundamental plant processes depends on its ability to activate the plasma membrane H+-ATPase, induced by eliciting the association of 14-3-3 proteins, a class of regulatory molecules widespread in eukaryotes. This discovery renewed interest in FC and prompted more recent studies aimed to ascertain the ability of the toxin to influence the interaction between 14-3-3 proteins and their numerous client proteins in animals, involved in the regulation of basic cellular processes and in the etiology of different diseases, including cancer. This review covers the different aspects of FC research partially treated in different previous reviews, starting from its discovery in 1964, with the aim to outline the extraordinary pathway which led this very uncommon diterpenoid to evolve from a phytotoxin into a tool in plant physiology and eventually into a 14-3-3-targeted drug

AIF-1 gene does not confer susceptibility to Behçet's disease: Analysis of extended haplotypes in Sardinian population

Background BehcEet's disease (BD) is a polygenic immune-mediated disorder characterized by a close association with the HLA-B∗51 allele. The HLA region has a strong linkage disequilibrium (LD) and carries several genetic variants (e.g. MIC-A, TNF-α genes) identified as associated to BD because of their LD with HLA-B∗51. In fact, the HLA-B∗51 is inherited as part of extended HLA haplotypes which are well preserved in patients with BD. Sardinian population is highly differentiated from other Mediterranean populations because of a distinctive genetic structure with very highly preserved HLA haplotypes. Patients and methods In order to identify other genes of susceptibility to BD within the HLA region we investigated the distribution of human Allograft Inflammatory Factor-1 (AIF-1) gene variants among BD patients and healthy controls from Sardinia. Six (rs2736182; rs2259571; rs2269475; rs2857597; rs13195276; rs4711274) AIF-1 single nucleotide polymorphisms (SNPs) and related extended haplotypes have been investigated as well as their LD within the HLA region and with HLA-B∗51. Overall, 64 BD patients, 43 HLA-B∗51 positive healthy controls (HC) and 70 random HC were enrolled in the study. Results HLA-B∗51 was the only allele with significantly higher frequency (pc = 0.0021) in BD patients (40.6%) than in HC (9.8%). The rs2259571TAIF-1 variant had a significantly reduced phenotypic, but not allelic frequency in BD patients (72.1%; pc = 0.014) compared to healthy population (91.3%). That was likely due to the LD between HLA-B∗51 and rs2259571G(pc= 9E-5), even though the rs2259571Gdistribution did not significantly differ between BD patients and HC. Conclusion No significant difference in distribution of AIF-1 SNPs haplotypes was observed between BD patients and HC and between HLA-B∗51 positive BD patients and HLA-B∗51 positive HC. Taken together, these results suggest that AIF-1 gene is not associated with susceptibility to BD in Sardinia

VUV-Vis optical characterization of Tetraphenyl-butadiene films on glass and specular reflector substrates from room to liquid Argon temperature

The use of efficient wavelength-shifters from the vacuum-ultraviolet to the photosensor's range of sensitivity is a key feature in detectors for Dark Matter search and neutrino physics based on liquid argon scintillation detection. Thin film of Tetraphenyl-butadiene (TPB) deposited onto the surface delimiting the active volume of the detector and/or onto the photosensor optical window is the most common solution in current and planned experiments. Detector design and response can be evaluated and correctly simulated only when the properties of the optical system in use (TPB film + substrate) are fully understood. Characterization of the optical system requires specific, sometimes sophisticated optical methodologies. In this paper the main features of TPB coatings on different, commonly used substrates is reported, as a result of two independent campaigns of measurements at the specialized optical metrology labs of ENEA and University of Tor Vergata. Measured features include TPB emission spectra with lineshape and relative intensity variation recorded as a function of the film thickness and for the first time down to LAr temperature, as well as optical reflectance and transmittance spectra of the TPB coated substrates in the wavelength range of the TPB emission

The Salt Tolerance Related Protein (STRP) Mediates Cold Stress Responses and Abscisic Acid Signalling in Arabidopsis thaliana

Low temperature stress is one of the major causes of crop yield reduction in agriculture. The alteration of gene expression pattern and the accumulation of stress-related proteins are the main strategies activated by plants under this unfavourable condition. Here we characterize the Arabidopsis thaliana Salt Tolerance Related Protein (STRP). The protein rapidly accumulates under cold treatment, and this effect is not dependent on transcriptional activation of the STRP gene, but on the inhibition of proteasome-mediated degradation. Subcellular localization of STRP was determined by the transient expression of STRP-YFP in A. thaliana protoplasts. STRP is localized into the cytosol, nucleus, and associated to the plasma membrane. Under cold stress, the membrane-associated fraction decreases, while in the cytosol and in the nucleus STRP levels strongly increase. STRP has high similarity with WCI16, a wheat Late Embryogenesis Abundant (LEA)-like protein. Despite no canonical LEA motifs in the STRP sequence are present, physicochemical characterization demonstrated that STRP shares common features with LEA proteins, being a high hydrophilic unstructured protein, highly soluble after boiling and with cryoprotectant activity. To clarify the physiological function of STRP, we characterized the phenotype and the response to low temperature stress of the strp knockout mutant. The mutation causes an equal impairment of plant growth and development both in physiological and cold stress conditions. The strp mutant is more susceptible to oxidative damage respect to the wild type, showing increased lipid peroxidation and altered membrane integrity. Furthermore, the analysis of Abscisic acid (ABA) effects on protein levels demonstrated that the hormone induces the increase of STRP levels, an effect in part ascribable to its ability to activate STRP expression. ABA treatments showed that the strp mutant displays an ABA hyposensitive phenotype in terms of seed germination, root development, stomata closure and in the expression of ABA-responsive genes. In conclusion, our results demonstrate that STRP acts as a multifunctional protein in the response mechanisms to low temperature, suggesting a crucial role for this protein in stress perception and in the translation of extracellular stimuli in an intracellular response

Frequency of the New HLA-B*2709 Allele in Ankylosing Spondylitis Patients and Healthy Individuals

We have recently described a new HLA-B27 subtype, named HLA-B*2709 (Del Porto et al. 1994). This allele is identical to the subtype most frequently found in Caucasoids, HLA-B*2705, except for a single amino acid substitution (Asp to His) in position 116. This residue, that is part of the F pocket of the molecule, has been shown to be relevant in determining which C-terminal amino acid of HLA-class I-binding peptides can be accomodated into the groove (Elliott, 1993). In nonamer peptides, this aminoacid corresponds to a primary anchor position (P9; Madden et al., 1992). Accordingly, we have previously shown that B2709 molecule hardly accepts nonamer peptides with an Arg or Tyr in P9, while the same amino acids represent good anchors for B2705 molecules (Fiorillo et al., 1995). Special attention is focused on HLA-B27 subtypes because of the strong association of B27 with ankylosing spondylitis (AS). More than 90% of AS patients are B27-positive and, conversely, about 4% of B27-positive individuals in the population are affected. This represents a relative risk over 100, that is the highest in HLA-disease associations. However, little is known on the pathogenic mechanisms of the disease. Following the hypothesis that an antigenic B27-binding peptide is involved in the disease (the so-called arthritogenic peptide), differential association with the different B27 subtypes may give a clue on the nature of such peptide. If two subtypes of partially overlapping peptide binding specificity are found to be both AS-associated, this would restrict the search for peptides that can be bound by both allelic products. Conversely, if a B27 subtype is found to be non AS-associated, this would be even more helpful in eliminating an array of peptides as possible candidates

Polymer physics indicates chromatin folding variability across single-cells results from state degeneracy in phase separation

The spatial organization of chromosomes has key functional roles, yet how chromosomes fold remains poorly understood at the single-molecule level. Here, we employ models of polymer physics to investigate DNA loci in human HCT116 and IMR90 wild-type and cohesin depleted cells. Model predictions on single-molecule structures are validated against single-cell imaging data, providing evidence that chromosomal architecture is controlled by a thermodynamics mechanism of polymer phase separation whereby chromatin self-assembles in segregated globules by combinatorial interactions of chromatin factors that include CTCF and cohesin. The thermodynamics degeneracy of single-molecule conformations results in broad structural and temporal variability of TAD-like contact patterns. Globules establish stable environments where specific contacts are highly favored over stochastic encounters. Cohesin depletion reverses phase separation into randomly folded states, erasing average interaction patterns. Overall, globule phase separation appears to be a robust yet reversible mechanism of chromatin organization where stochasticity and specificity coexist

Helminth Parasites of Two Species of Lepomis (Osteichthyes: Centrarchidae) from an Urban Watershed and their Potential Use in Environmental Monitoring

We provide a checklist of the common parasites of bluegill (Lepomis macrochirus) and redbreast sunfish (Lepomis auritus) collected from eight creeks within an urban watershed located in Columbus, Georgia. A total of 12 parasite species were observed from 427 fish dissected. Bluegill (n = 222) were infected with 11 species, which included five species of larval helminths (Proteocephalus sp., Bothriocephalus sp., Posthodiplostomum minimum, Diplostomulum sp. and Clinostomum complanatum), one adult trematode (Pisciamphistoma stunkardi), four adult nematodes (Philometra sp., Philometra intraoculus, Spinetectus carolini and Camallanus oxycephalus) and one adult acanthocephalan (Neochinorhynchus cylindratus). Redbreast sunfish (n = 205) were infected with the same parasite species, except for the absence of larval Bothriocephalus sp. and the presence of an adult trematode (Crepidostomum cooperi). Metacercariae of the trematode P. minimum were the most common parasite in both fish species. Similar parasite communities in these sunfishes suggest that these species share similar microhabitats within the watershed, food resources and foraging sites. Seasonal comparison between the number of summer and winter parasites indicate a greater mean number of parasites per host in summer. We discuss the utility of such baseline parasite data in the potential environmental monitoring of the Bull and Upatoi Creeks watershed