A preliminary investigation of serological tools for the detection of Onchocerca lupi infection in dogs

Onchocerca lupi is a neglected filarioid causing nodular lesions associated with acute or chronic ocular disease in dogs. Despite the recent appraisal of its zoonotic potential, human cases are increasingly reported in the Old and New Worlds. Therefore, the development of accurate tools for the rapid diagnosis of O. lupi infections in dogs is becoming a priority. In this study, we conducted a preliminary investigation aimed at evaluating the usefulness of a commercially available ELISA test for the detection of O. lupi antigens in canine sera. The potential use of this tool for larger epidemiological studies of canine onchocerciasis is discussed.     

IL‐4‐induced gene 1 maintains high Tob1 expression that contributes to TCR unresponsiveness in human T helper 17 cells

Human Th17 cells have a limited proliferative capacity compared to other T‐cell subsets. We have shown that human Th17 cells display impaired IL‐2 production due to IL‐4‐induced gene 1 (IL4I1) upregulation. Here, we show that in human Th17 cells, IL4I1 also maintains high levels of Tob1, a member of the Tob/BTG (B‐cell traslocation gene) antiproliferative protein family, which prevents cell‐cycle progression mediated by TCR stimulation. Indeed, Th17 cells exhibited higher levels of Tob1 than Th1 cells in both resting and TCR‐activated conditions. Accordingly, the expression of positive regulators of the cell cycle (cyclin A, B, C, and E and Cdk2), as well as of Skp2, which promotes Tob1 degradation, was lower in Th17 cells than in Th1 cells. Tob1 expression in human Th17 cells correlated with both RAR (retinoic acid receptor)‐related orphan receptor C (RORC) and IL4I1 levels. However, RORC was not directly involved in the regulation of Tob1 expression, whereas IL4I1 silencing in Th17 cells induced a substantial decrease of Tob1 expression. These data suggest that IL4I1 upregulation in human Th17 cells limits their TCR‐mediated expansion not only by blocking the molecular pathway involved in the activation of the IL‐2 promoter, but also by maintaining high levels of Tob1, which impairs entry into the cell cycle.     

Thermotropic liquid crystals from biomacromolecules

Complexation of biomacromolecules (e.g., nucleic acids, proteins, or viruses) with surfactants containing flexible alkyl tails, followed by dehydration, is shown to be a simple generic method for the production of thermotropic liquid crystals. The anhydrous smectic phases that result exhibit biomacromolecular sublayers intercalated between aliphatic hydrocarbon sublayers at or near room temperature. Both this and low transition temperatures to other phases enable the study and application of thermotropic liquid crystal phase behavior without thermal degradation of the biomolecular components.Liquid crystals (LCs) play an important role in biology because their essential characteristic, the combination of order and mobility, is a basic requirement for self-organization and structure formation in living systems (1–3). Thus, it is not surprising that the study of LCs emerged as a scientific discipline in part from biology and from the study of myelin figures, lipids, and cell membranes (4). These and the LC phases formed from many other biomolecules, including nucleic acids (5, 6), proteins (7, 8), and viruses (9, 10), are classified as lyotropic, the general term applied to LC structures formed in water and stabilized by the distinctly biological theme of amphiphilic partitioning of hydrophilic and hydrophobic molecular components into separate domains. However, the principal thrust and achievement of the study of LCs has been in the science and application of thermotropic materials, structures, and phases in which molecules that are only weakly amphiphilic exhibit LC ordering by virtue of their steric molecular shape, flexibility, and/or weak intermolecular interactions [e.g., van der Waals and dipolar forces (11)]. These characteristics enable thermotropic LCs (TLCs) to adopt a wide variety of exotic phases and to exhibit dramatic and useful responses to external forces, including, for example, the electro-optic effects that have led to LC displays and the portable computing revolution. This general distinction between lyotropic LCs and TLCs suggests there may be interesting possibilities in the development of biomolecular or bioinspired LC systems in which the importance of amphiphilicity is reduced and the LC phases obtained are more thermotropic in nature. Such biological TLC materials are very appealing for several reasons. Most biomacromolecules were extensively characterized in aqueous environments, but in TLC phases, their solvent-free properties and functions could be investigated in a state in which no or only traces of water are present. Water exhibits a high dielectric constant and has the ability to form hydrogen bonds, greatly influencing the structure and functions of biomacromolecules or compromising electronic properties such as charge transport (12–15). Indeed, anhydrous TLC systems containing glycolipids (16–19), ferritin (20), and polylysine have been reported (21–23). However, a general approach to fabricating TLCs based on nucleic acids, polypeptides, proteins, and protein assemblies of large molecular weights such as virus particles remains elusive.Here we propose that the combination of biomaterials with suitably chosen surfactants, followed by dehydration, can be effectively applied as a simple generic scheme for producing biomacromolecular-based TLCs. We demonstrate that biological TLCs can be made from a remarkable range of biomolecules and bio-inspired molecules, including nucleic acids, polypeptides, fusion proteins, and viruses. TLC materials typically combine rigid or semirigid anisometric units, which introduce orientational anisotropy, with flexible alkyl chains, which suppress crystallization (24). In the present experiments, negatively charged biomolecules and bio-inspired molecules act as rigid parts, and cationic surfactants make up the flexible units to produce TLC phases with remarkably low LC-isotropic clearing temperatures, which is another TLC signature. Electrostatic interactions couple these rigid and flexible components into hybrid assemblies, which then order into lamellar phases of alternating rigid and flexible layers (Fig. 1) stabilized by the tendency in TLCs for rigid and flexible to spatially segregate (25).Open in a separate windowFig. 1.Proposed structures of TLCs formed by the biological building blocks complexed with surfactants, showing sketches of various lamellar phases and the corresponding phase transition temperatures (°C). The lamellar bilayer structures are made of, alternately, a sublayer of the biomacromolecules and an interdigitated sublayer of the surfactants, where the negatively charged parts of the biomolecules (e.g., phosphate groups of ssDNA and ssRNA, glutamate residues of supercharged ELPs, and N-terminal glutamate and aspartate residues of pVIII protein in phages) electrostatically interact with the cationic head groups of the surfactants. For the ssDNA–DOAB and ssRNA–DOAB smectic TLCs, the oligonucleotides are randomly orientated in the DNA (RNA) sublayers. For the ELP–DDAB complexes, in addition to the bilayer smectic phase, a modulated smectic (Sm_mod) phase is observed at lower temperature. For the phage–DOAB–DDAB lamellar structures, rodlike virus particles are embedded in a sublayer between interdigitated surfactants with additional in-plane orientational order.     

MicroRNAs bind to Toll-like receptors to induce prometastatic inflammatory response

MicroRNAs (miRNAs) are small noncoding RNAs, 19-24 nucleotides in length, that regulate gene expression and are expressed aberrantly in most types of cancer. MiRNAs also have been detected in the blood of cancer patients and can serve as circulating biomarkers. It has been shown that secreted miRNAs within exosomes can be transferred from cell to cell and can regulate gene expression in the receiving cells by canonical binding to their target messenger RNAs. Here we show that tumor-secreted miR-21 and miR-29a also can function by another mechanism, by binding as ligands to receptors of the Toll-like receptor (TLR) family, murine TLR7 and human TLR8, in immune cells, triggering a TLR-mediated prometastatic inflammatory response that ultimately may lead to tumor growth and metastasis. Thus, by acting as paracrine agonists of TLRs, secreted miRNAs are key regulators of the tumor microenvironment. This mechanism of action of miRNAs is implicated in tumor-immune system communication and is important in tumor growth and spread, thus representing a possible target for cancer treatment.     

Brain conditioning is instrumental for successful microglia reconstitution following hematopoietic stem cell transplantation

The recent hypothesis that postnatal microglia are maintained independently of circulating monocytes by local precursors that colonize the brain before birth has relevant implications for the treatment of various neurological diseases, including lysosomal storage disorders (LSDs), for which hematopoietic cell transplantation (HCT) is applied to repopulate the recipient myeloid compartment, including microglia, with cells expressing the defective functional hydrolase. By studying wild-type and LSD mice at diverse time-points after HCT, we showed the occurrence of a short-term wave of brain infiltration by a fraction of the transplanted hematopoietic progenitors, independently from the administration of a preparatory regimen and from the presence of a disease state in the brain. However, only the use of a conditioning regimen capable of ablating functionally defined brain-resident myeloid precursors allowed turnover of microglia with the donor, mediated by local proliferation of early immigrants rather than entrance of mature cells from the circulation.