First Attempt To Validate Human IgG Antibody Response to Nterm-34kDa Salivary Peptide as Biomarker for Evaluating Exposure to Aedes aegypti Bites

Background

Much effort is being devoted for developing new indicators to evaluate the human exposure to Aedes mosquito bites and the risk of arbovirus transmission. Human antibody (Ab) responses to mosquito salivary components could represent a promising tool for evaluating the human-vector contact.

Methodology/Principal findings

To develop a specific biomarker of human exposure to Aedes aegypti bites, we measured IgG Ab response to Ae. aegypti Nterm-34 kDa salivary peptide in exposed children in 7 villages of Southern Benin (West Africa). Results showed that specific IgG response presented high inter-individual heterogeneity between villages. IgG response was associated with rainfall and IgG level increased from dry (low exposure) to rainy (high exposure) seasons. These findings indicate that IgG Ab to Nterm-34 kDa salivary peptide may represent a reliable biomarker to detect variation in human exposure to Ae. aegypti bites.

Conclusion/Significance

This preliminary study highlights the potential use of Ab response to this salivary peptide for evaluating human exposure to Ae. aegypti. This biomarker could represent a new promising tool for assessing the risk of arbovirus transmission and for evaluating the efficacy of vector control interventions.     

Mannose 6 dephosphorylation of lysosomal proteins mediated by acid phosphatases Acp2 and Acp5

Mannose 6-phosphate (Man6P) residues represent a recognition signal required for efficient receptor-dependent transport of soluble lysosomal proteins to lysosomes. Upon arrival, the proteins are rapidly dephosphorylated. We used mice deficient for the lysosomal acid phosphatase Acp2 or Acp5 or lacking both phosphatases (Acp2/Acp5(-/-)) to examine their role in dephosphorylation of Man6P-containing proteins. Two-dimensional (2D) Man6P immunoblot analyses of tyloxapol-purified lysosomal fractions revealed an important role of Acp5 acting in concert with Acp2 for complete dephosphorylation of lysosomal proteins. The most abundant lysosomal substrates of Acp2 and Acp5 were identified by Man6P affinity chromatography and mass spectrometry. Depending on the presence of Acp2 or Acp5, the isoelectric point of the lysosomal cholesterol-binding protein Npc2 ranged between 7.0 and 5.4 and may thus regulate its interaction with negatively charged lysosomal membranes at acidic pH. Correspondingly, unesterified cholesterol was found to accumulate in lysosomes of cultured hepatocytes of Acp2/Acp5(-/-) mice. The data demonstrate that dephosphorylation of Man6P-containing lysosomal proteins requires the concerted action of Acp2 and Acp5 and is needed for hydrolysis and removal of degradation products.     

Allodynic skin in post-herpetic neuralgia: histological correlates

Most post-herpetic neuralgia (PHN) patients suffer from tactile allodynia (pain evoked by lightly touching the skin) and it is frequently the dominant clinical manifestation. The pathophysiology of tactile allodynia in PHN patients is poorly understood and this is one of the major limits to the development of appropriate therapies. Epidermal nerve fibres (ENFs) are free nerve endings of small-diameter A-delta and C primary afferents, which can easily be assessed by neurodiagnostic skin biopsy (NSB). The aim of this study was to establish the correlation between the residual epidermal innervation of the allodynic skin and the intensity of tactile allodynia in that area. Twenty-five patients (13 males and 12 females) with PHN were enrolled. Eighteen patients had PHN in the thoracic dermatome, four in the cervical, two in the trigeminal and one in the lumbar. The severity of allodynia evoked by a paintbrush was graded according to an eleven-point numerical scale. A skin biopsy was obtained from the maximal allodynia area and from the contralateral skin. Nerve fibres were labelled with indirect immunofluorescence. Results showed that epidermal innervation was lower in the allodynic skin than in the contralateral skin, although there was great variability among patients. There was no correlation between severity of allodynia and epidermal innervation of the PHN skin. In conclusion, the present study further indicates peripheral nervous system involvement in PHN but does not support a direct correlation between epidermal innervation changes and tactile allodynia.     

Regional factors rather than forest type drive the community structure of soil living oribatid mites (Acari, Oribatida)

Most European forests are managed by humans. However, the manner and intensity of management vary. While the effect of forest management on above-ground communities has been investigated in detail, effects on the below-ground fauna remain poorly understood. Oribatid mites are abundant microarthropods in forest soil and important decomposers in terrestrial ecosystems. Here, we investigated the effect of four forest types (i.e., managed coniferous forests; 30 and 70 years old managed beech forests; natural beech forests) on the density, diversity and community structure of oribatid mites (Acari). The study was replicated at three regions in Germany: the Swabian Alb, the Hainich and the Schorfheide. To relate changes in oribatid mite community structure to environmental factors, litter mass, pH, C and N content of litter, fine roots and C content of soil were measured. Density of oribatid mites was highest in the coniferous forests and decreased in the order 30 years old, 70 years old, and natural beech forests. Mass of the litter layer and density of oribatid mites were strongly correlated indicating that the litter layer is an important factor regulating oribatid mite densities. Diversity of oribatid mites was little affected by forest type indicating that they harbor similar numbers of niches. Species composition differed between the forest types, suggesting different types of niches. The community structure of oribatid mites differed more strongly between the three regions than between the forest types indicating that regional factors are more important than effects associated with forest type.     

Discovery of tetrahydropyridopyrimidine phosphodiesterase 10A inhibitors for the treatment of schizophrenia

We describe the discovery of potent and orally bioavailable tetrahydropyridopyrimidine inhibitors of phosphodiesterase 10A by systematic optimization of a novel HTS lead. Lead compound THPP-1 exhibits nanomolar potencies, excellent pharmacokinetic properties, and a clean off-target profile. It displays in vivo target engagement as measured by increased rat striatal cGMP levels upon oral dosing. It shows dose-dependent efficacy in a key pharmacodynamic assay predictive of antipsychotic activity, the psychostimulant-induced rat hyperlocomotion assay. Further, THPP-1 displays significantly fewer preclinical adverse events in assays measuring prolactin secretion, catalepsy, and weight gain, in contrast to the typical and atypical antipsychotics haloperidol and olanzapine.     

Application of the ELISPOT method for comparative analysis of interleukin (IL)-6 and IL-10 secretion in peripheral blood of patients with astroglial tumors

Glioblastoma, (grade IV astrocytoma), is characterized by rapid growth and resistance to treatment. Identification of markers of aggressiveness in this tumor could represent new therapeutic targets. Interleukins (IL)-6 and IL-10 may be considered as possible candidates, regulating cell growth, resistance to chemotherapy and angiogenesis. ELISPOT method provides a useful tool for the determination of the exact cell number of peripheral lymphocytes secreting a specific cytokine. IL-6 and IL-10 secretion levels were determined using ELISPOT methodology in peripheral blood mononuclear cells of 18 patients with astrocytic neoplasms (3 grade II and 15 grade IV), in parallel with 18 healthy controls. Additionally, immunohistochemical expression of these two cytokines was performed in paraffin-embedded neoplastic tissue in 12 of these patients. The secretion of IL-6 from peripheral monocytes was significantly higher in glioma patients compared to controls (P = 0.0003). In addition, IL-10 secretion from peripheral mononuclear and tumor cells of glioma patients was also higher as compared to healthy controls (P = 0.0002). Based on immunohistochemical staining, IL-6 expression was localized in tumor cells and macrophages as well as in areas of large ischemic necrosis, while the major source of IL-10 expression in glioblastomas was the microglia/macrophage cells. It is suggested that IL-10 contributes to the progression of astrocytomas by suppressing the patient’s immune response, whereas IL-6 provides an additional growth advantage. This study demonstrates for the first time the usefulness of ELISPOT in estimating the secretion of IL-6 and IL-10 from peripheral blood and the correlation of their expression in neoplastic cells. Christina Piperi and Penelope Korkolopoulou have equally contributed to this work.     

A comparative Mössbauer study of the mineral cores of human H-chain ferritin employing dioxygen and hydrogen peroxide as iron oxidants

Ferritins are ubiquitous iron storage and detoxification proteins distributed throughout the plant and animal kingdoms. Mammalian ferritins oxidize and accumulate iron as a ferrihydrite mineral within a shell-like protein cavity. Iron deposition utilizes both O₂ and H₂O₂ as oxidants for Fe²⁺ where oxidation can occur either at protein ferroxidase centers or directly on the surface of the growing mineral core. The present study was undertaken to determine whether the nature of the mineral core formed depends on the protein ferroxidase center versus mineral surface mechanism and on H₂O₂ versus O₂ as the oxidant. The data reveal that similar cores are produced in all instances, suggesting that the structure of the core is thermodynamically, not kinetically controlled. Cores averaging 500 Fe/protein shell and diameter  2.6 nm were prepared and exhibited superparamagnetic blocking temperatures of 19 and 22 K for the H₂O₂ and O₂ oxidized samples, respectively. The observed blocking temperatures are consistent with the unexpectedly large effective anisotropy constant K_eff = 312 kJ/m³ recently reported for ferrihydrite nanoparticles formed in reverse micelles [E.L. Duarte, R. Itri, E. Lima Jr., M.S. Batista, T.S. Berquó and G.F. Goya, Large Magnetic Anisotropy in ferrihydrite nanoparticles synthesized from reverse micelles, Nanotechnology 17 (2006) 5549–5555.]. All ferritin samples exhibited two magnetic phases present in nearly equal amounts and ascribed to iron spins at the surface and in the interior of the nanoparticle. At 4.2 K, the surface spins exhibit hyperfine fields, H_hf, of 436 and 445 kOe for the H₂O₂ and O₂ samples, respectively. As expected, the spins in the interior of the core exhibit larger H_hf values, i.e. 478 and 486 kOe for the H₂O₂ and O₂ samples, respectively. The slightly smaller hyperfine field distribution DH_hf for both surface (78 kOe vs. 92 kOe) and interior spins (45 kOe vs. 54 kOe) of the O₂ sample compared to the H₂O₂ samples implies that the former is somewhat more crystalline.     

Cellular redox-status is associated with regulation of frond division in <Emphasis Type="Italic">Spirodela polyrrhiza</Emphasis>

We investigated a possible relationship between the levels of reactive oxygen species (ROS) and the stimulation of frond division of the aquatic plant Spirodela polyrrhiza (duckweed) during a 7-day experimental culture period. In particular, we monitored superoxide concentration using a state-of-the-art cell biosensor. A considerable reduction in ROS and superoxide concentration was observed during the first 2 days of culture, whereas duckweed cultures achieved near exponential growth rates after the second day. In addition, apoptotic markers such as the cytoplasmic concentration of cytochrome c, mitochondrial membrane depolarization and the activity of caspase-3 declined during the culture period and at least before daughter frond maturation. We suggest that S. polyrrhiza frond division may have been stimulated by the observed reduction of free radicals and the associated avoidance of cell apoptotic pathways in cultured plants.