Acute phase proteins and pesticide exposure

Gamma mobility C-reactive protein (CRP) level was determined in the sera of persons occupationally exposed to pesticides and controls in conjunction with serum protein analysis and other biochemical and enzymologic tests. Workers chronically exposed to dieldrin and pentachlorophenol showed significantly higher prevalence of CRP than the unexposed persons. In addition, the pentachlorophenol-exposed subjects revealed significantly elevated levels of total bilirubin and creatine phosphokinase, although the levels were within normal limits. The results suggest that chronic exposure to pentachlorophenol may have been responsible for the difference in the prevalence of CRP between the pentachlorophenol and control groups.     

Geographical differences in erythemally-weighted UV measured at mid-latitude USDA sites.

UV measurements from instruments maintained by USDA at 16 mid-latitude sites were analysed to investigate geographic differences. Fifteen of the sites are in North America, and one is in New Zealand. The instruments measure erythemally weighted UV radiation, and the results are presented in terms of UV Index (UVI). The focus of this work is on data from 2003, but the main results are also shown for years 2002 and 2004. In the North American sites, the peak UVI values increase by approximately 15% between latitudes 47 degrees N and 40 degrees N, and they show an increase with altitude of approximately 15% in the first kilometer, but much smaller rates of increase above that level. Peak UV intensities in the New Zealand site (45 degrees S, alt. 0.37 km) exceed those at comparable latitudes and altitudes in North America by 41 +/- 5%, and are more comparable with those over 1 km higher and 5 degrees closer to the equator. The number of observations on these days that exceeded various thresholds of UVI showed similar patterns. Furthermore, the number of days in which the peak values exceeded various thresholds also showed similar patterns, with the number of extreme values in New Zealand being anomalously high. For example, the only sites in North America where UVI exceeded 12 were at the high altitude sites in Colorado and Utah, for which there were 53 days, 6 days and 2 days respectively at the 3.2 km, 1.6 and 1.4 km sites. By contrast, the peak UVI at Lauder (0.37 km) exceeded 12 on 17 days. Lauder was the only site under 1 km altitude where the UVI exceeded 11 on a regular basis (48 days). The optical depths at Lauder were significantly lower than at all North American sites. These, together with the lower ozone amounts and the closer Earth-Sun separation in summer all contribute to the relatively high UV intensities at the New Zealand site. Other sites in New Zealand show similar increases compared with corresponding sites in North America, and the differences persist from year to year. The contrast in UV between New Zealand and North America is similar to that observed previously between New Zealand and Europe. During winter months, the UVI in New Zealand is not particularly high, giving a larger summer/winter contrast in UVI, which may be important from a health perspective.     

Occludin oligomeric assemblies at tight junctions of the blood–brain barrier are altered by hypoxia and reoxygenation stress

Hypoxic (low oxygen) and reperfusion (post‐hypoxic reoxygenation) phases of stroke promote an increase in microvascular permeability at tight junctions (TJs) of the blood–brain barrier (BBB) that may lead to cerebral edema. To investigate the effect of hypoxia (Hx) and reoxygenation on oligomeric assemblies of the transmembrane TJ protein occludin, rats were subjected to either normoxia (Nx, 21% O₂, 60 min), Hx (6% O₂, 60 min), or hypoxia/reoxygenation (H/R, 6% O₂, 60 min followed by 21% O₂, 10 min). After treatment, cerebral microvessels were isolated, fractionated by detergent‐free density gradient centrifugation, and occludin oligomeric assemblies associated with plasma membrane lipid rafts were solubilized by perfluoro‐octanoic acid (PFO) exclusively as high molecular weight protein complexes. Analysis by non‐reducing and reducing sodium dodecyl sulfate (SDS)–polyacrylamide gel electrophoresis/western blot of PFO‐solubilized occludin revealed that occludin oligomeric assemblies co‐localizing with ‘TJ‐associated’ raft domains contained a high molecular weight ‘structural core’ that was resistant to disassembly by either SDS or a hydrophilic reducing agent ex vivo, and by Hx and H/R conditions in vivo. However, exposure of PFO‐solubilized occludin oligomeric assemblies to SDS ex vivo revealed the non‐covalent association of a significant amount of dimeric and monomeric occludin isoforms to the disulfide‐bonded inner core, and dispersal of these non‐covalently attached occludin subunits to lipid rafts of higher density in vivo was differentially promoted by Hx and H/R. Our data suggest a model of isoform interaction within occludin oligomeric assemblies at the BBB that enables occludin to simultaneously perform a structural role in inhibiting paracellular diffusion, and a signaling role involving interactions of dimeric and monomeric occludin isoforms with a variety of regulatory molecules within different plasma membrane lipid raft domains.     

Membrane progesterone receptor expression in mammalian tissues: A review of regulation and physiological implications

The recent discovery of a novel, membrane localized progestin receptor (mPR) unrelated to the classical progesterone receptor (PR) in fishes and its subsequent identification in mammals suggests a potential mediator of non-traditional progestin actions, particularly in tissues where PR is absent. While early studies on mPR focused on final oocyte maturation in fishes, more current studies have examined mPRs in multiple mammalian systems in both reproductive and non-reproductive tissues as well as in diseased tissues. Here we review the current data on mPR in mammalian systems including male and female reproductive tracts, liver, neuroendocrine tissues, the immune system and breast and ovarian cancer. We also provide new data demonstrating mPR expression in the RAW 264.7 immune cell line and bone marrow-derived macrophages as well as mPR expression and downstream gene regulation in ovarian cancer cells.     

Influence of antimicrobial feed additives on broiler commensal posthatch gut microbiota development and performance

The effects of avilamycin, zinc bacitracin, and flavophospholipol on broiler gut microbial community colonization and bird performance in the first 17 days posthatch were investigated. Significant differences in gut microbiota associated with gut section, dietary treatment, and age were identified by terminal restriction fragment length polymorphism (T-RFLP), although no performance-related differences between dietary treatments were detected. Similar age-related shifts in the gut microbiota were identified regardless of diet but varied between the ilea and ceca. Interbird variabilities in ileal bacterial communities were reduced (3 to 7 days posthatch) in chicks fed with feed containing antimicrobial agents. Avilamycin and flavophospholipol had the most consistent effect on gut microbial communities. Operational taxonomic units (OTU) linked to changes in gut microbiota in birds on antimicrobial-supplemented diets were characterized and identified. Some OTUs could be identified to the species level; however, the majority could be only tentatively classified to the genus, family, order, or domain level. OTUs 140 to 146 (Lachnospiraceae), OTU 186/188 (Lactobacillus johnsonii), OTU 220 (Lachnospiraceae), OTUs 284 to 288 (unclassified bacterial spp. or Ruminococcaceae), OTU 296/298 (unclassified bacterium or Clostridiales), and OTU 480/482 (Oxalobacteraceae) were less prevalent in the guts of chicks fed antimicrobial-supplemented diets. OTU 178/180 (Lactobacillus crispatus), OTU 152 (Lactobacillus reuteri or unclassified Clostridiales), OTU 198/200 (Subdoligranulum spp.), and OTU 490/492 (unclassified bacterium or Enterobacteriaceae) were less prevalent in the gut of chicks raised on the antimicrobial-free diet. The identification of key bacterial species influenced by antimicrobial-supplemented feed immediately posthatch may assist in the formulation of diets that facilitate beneficial gut microbial colonization and, hence, the development of alternatives to current antimicrobial agents in feed for sustainable poultry production.     

Transformation of, and heterologous protein expression in, Lactobacillus agilis and Lactobacillus vaginalis isolates from the chicken gastrointestinal tract

Lactobacilli are naturally found in the gastrointestinal tract of chickens, and there is interest in utilizing autochthonous strains for the delivery of therapeutic proteins. Previously we identified three chicken-derived Lactobacillus strains, Lactobacillus agilis La3, Lactobacillus vaginalis Lv5, and Lactobacillus crispatus Lc9, which persist in the gastrointestinal tract of chickens fed either a commercial or high-protein diet. In the current study, we investigated the ability to electrotransform these strains, determined plasmid vector stability, and compared reporter gene expression directed by several different promoters. The La3 and Lv5 strains were reproducibly transformed with efficiencies of 10(8) and 10(6) transformants per microgram of plasmid DNA, respectively. The third strain tested, L. crispatus Lc9, was recalcitrant to all transformation protocols examined. The plasmid vectors pTRK563 and pTRKH2 were maintained over 100 generations in La3 and Lv5, respectively. The ability of La3 and Lv5 to express the heterologous reporter gene gfp was analyzed using heterologous and homologous promoters. Transformants of both La3 and Lv5 containing the La3 ldhL promoter were the most fluorescent. To our knowledge, this is the first report of successful transformation and heterologous protein expression in L. agilis and L. vaginalis. The ability of these strains to express heterologous proteins in vitro indicates their potential utility as in vivo delivery vectors for therapeutic peptides to the chicken gastrointestinal tract.     

1,3,4-Trisubstituted pyrrolidine CCR5 receptor antagonists: modifications of the arylpropylpiperidine side chains

The 4-(3-phenylprop-1-yl)piperidine moiety of the 1,3,4-trisubstituted pyrrolidine CCR5 antagonist 1 was modified with electron deficient aromatics as well as replacement of the benzylic methylene with sulfones, gem-difluoromethylenes and alcohols in an effort to balance the antiviral potency with reasonable pharmacokinetics.     

1,3,4-Trisubstituted pyrrolidine CCR5 receptor antagonists. Part 4: synthesis of N-1 acidic functionality affording analogues with enhanced antiviral activity against HIV

A series of alpha-(pyrrolidin-1-yl)acetic acids is presented as selective and potent antivirals against HIV. Several of the pyrrolidine zwitterions demonstrated reasonable in vitro properties, enhanced antiviral activities and improved pharmacokinetic profiles over pyrrolidine 1.     

Polymeric Microspheres as Protein Transduction Reagents

Discovering the function of an unknown protein, particularly one with neither structural nor functional correlates, is a daunting task. Interaction analyses determine binding partners, whereas DNA transfection, either transient or stable, leads to intracellular expression, though not necessarily at physiologically relevant levels. In theory, direct intracellular protein delivery (protein transduction) provides a conceptually simpler alternative, but in practice the approach is problematic. Domains such as HIV TAT protein are valuable, but their effectiveness is protein specific. Similarly, the delivery of intact proteins via endocytic pathways (e.g. using liposomes) is problematic for functional analysis because of the potential for protein degradation in the endosomes/lysosomes. Consequently, recent reports that microspheres can deliver bio-cargoes into cells via a non-endocytic, energy-independent pathway offer an exciting and promising alternative for in vitro delivery of functional protein. In order for such promise to be fully exploited, microspheres are required that (i) are stably linked to proteins, (ii) can deliver those proteins with good efficiency, (iii) release functional protein once inside the cells, and (iv) permit concomitant tracking. Herein, we report the application of microspheres to successfully address all of these criteria simultaneously, for the first time. After cellular uptake, protein release was autocatalyzed by the reducing cytoplasmic environment. Outside of cells, the covalent microsphere–protein linkage was stable for ≥90 h at 37 °C. Using conservative methods of estimation, 74.3% ± 5.6% of cells were shown to take up these microspheres after 24 h of incubation, with the whole process of delivery and intracellular protein release occurring within 36 h. Intended for in vitro functional protein research, this approach will enable study of the consequences of protein delivery at physiologically relevant levels, without recourse to nucleic acids, and offers a useful alternative to commercial protein transfection reagents such as Chariot™. We also provide clear immunostaining evidence to resolve residual controversy surrounding FACS-based assessment of microsphere uptake.Many proteomic techniques can be used to build a picture of a protein with unknown function, but eventually the individual protein''s activity must be studied. Traditional transfection of encoding DNA permits intracellular expression, but often at uncontrolled, nonphysiological levels. Moreover, DNA transfection can neither deliver protein–inhibitor complexes nor readily deliver multiple proteins in a single experiment and thus exploit knowledge from proteomic protein–protein interaction analyses. In contrast, a truly generic protein transduction reagent could theoretically address all possibilities. We believe that polymeric microspheres could fulfill this role, and we have recently synthesized and characterized dual-functionalized, bio-compatible microspheres that permit intracellular tracking (1). Herein, we now report the development of those microspheres into a protein transduction reagent that can carry protein stably, deliver it efficiently to cells, release the protein in the cytoplasm, and concurrently permit fluorescent imaging of transduced cells.Phagocytosis of microspheres was first observed over 30 years ago (2). Perhaps more unexpectedly, uptake of polystyrene microspheres has recently been reported in many other, nonphagocytic cell types, some of which are traditionally considered to be resistant to DNA transfection and/or protein transduction. For example, microspheres are taken up readily by primary immune cells (3), embryonic stem cells (4), human neural stem cells (5), differentiating mouse neural stem cells (5), and several nonphagocytic cell lines (3, 6, 7). In all instances, the reported efficiency of cellular uptake is high, with “beadfection” of up to 90% of cells being typical (4, 5, 8). No additional reagents aside from the microspheres themselves are required in order to promote cellular uptake, and critically, no toxicity has been observed in any of the cell types beadfected, including HEK293T and L929 cells 2 days after beadfection (8), E14g2a embryonic stem cells 3 days after beadfection (4), and mouse and human neural stem cells 30 days after beadfection (5). In the latter case, the microspheres did not have any deleterious effect on the differentiation of human neural stem cells 30 days after beadfection (5).The mechanism of microsphere entry is also nontoxic, and compelling evidence has been published recently that polystyrene-based microspheres (from 0.2 μm to as large as 2 μm) enter cells via a non-endocytosis, energy-independent mechanism (8). Although unusual, such a mechanism is consistent with claims for the commercial reagent Chariot™ (9). Interestingly, a non-endocytic, energy-independent mechanism has also been reported for the entry of rhenium cluster/polymer hybrid particles into HeLa cells (10). Failure of the microspheres to be endocytosed, at least via a clathrin-dependent mechanism, is perhaps to be predicted, as their diameter considerably exceeds that of clathrin-coated vesicles (typically 100 nm). Bradley and co-workers (8) propose that the entry mechanism for polystyrene-based microspheres is one of passive diffusion in which the microsphere interacts with the membrane, anchors, and, after membrane reorganization, enters the cell, resulting in direct cytoplasmic localization.For functional analysis following transduction, the avoidance of endocytosis or phagocytosis is particularly relevant, as endocytosed particles are destined for endosomes and then, normally, for the lysosomes. The lowered pH of the endosome and, more seriously, the acidic and hydrolytic environment of the lysosome risk disruption of the protein structure and/or function. In contrast, for vaccine delivery (where liposomes can be employed), such exposure is advantageous because protein breakdown forms an essential part of antigen presentation. The potential for protein breakdown in endosomes is also irrelevant for the delivery of protein/peptide drugs such as insulin (for which microencapsulation has proven effective for long-term controlled drug release (11, 12)), as these drugs typically function in the extracellular environment, often exerting their effects by binding to membrane-bound receptors. Thus, although vehicles such as liposomes and nanoparticles are employed both extensively and successfully as drug and vaccine delivery vectors in vivo (13–16), they are far from ideal for studying the biological effect of a delivered protein in vitro. Colloidal particles are also endocytosed (17), and therefore these delivery vehicles may present similar disadvantages.Traditionally, protein transduction domains such as HIV TAT (18–20) or other cell-penetrating peptides (21–23) are used to deliver proteins to cells. Whereas positively charged peptides such as TAT are thought to enter the cells via macropinocytosis (reviewed in Ref. 24), a recent publication suggests that at least some cell-penetrating peptide/bio-cargo complexes (siRNA) are endocytosed (25). Here, although the cargoes avoid the lysosomes, acidification of the endosome is required for endosomal escape of the delivered cargo, and indeed, acidification appears to be a recurring requirement for endosomal escape of biomolecular cargoes using cell-penetrating peptides (reviewed in Ref. 24). Consequently, cell-penetrating peptides are unlikely to become generic tools for functional protein delivery.In contrast, the recent demonstrations that polystyrene microspheres can carry a variety of molecular cargoes with them into the cytoplasm (4, 5, 7, 26, 27) make them particularly exciting as potential vectors for delivering functional proteins and/or protein complexes. β-Galactosidase retains its activity when delivered via this route (7), confirming the potential of microspheres to act as generic protein-delivery vehicles. However, delivered proteins have to date remained tethered to the microspheres, and thus existing studies are limited to proteins that are active in the cytoplasm and, critically, retain their activity when immobilized on polystyrene. For the broad-based study of protein function, the subsequent release of the delivered protein within the cell is desirable.An ideal technology would deliver any protein to any cell type and release that protein in the cell, where it could undertake its normal activity. Here we report the first example of such a microsphere-based approach. Protein is delivered on microspheres and then released in the cell by the reducing cytoplasmic environment. This release is mediated by a linker that attaches the protein stably and covalently to the microspheres in vitro but intracellularly is cleaved over a period of hours. It has already been shown that microspheres are taken up with high efficiency by a range of cell types and can carry a variety of cargoes. Because the chemistry of the linker described herein is amenable to linkage with any molecule containing a free amine moiety, the technology provides a new generic platform for in vitro, cell-based delivery of individual proteins, protein complexes, protein mixtures, or other amino-functionalized molecules.