Stress indicators in minorities with multiple sclerosis

Black Americans with multiple sclerosis (MS) experience higher levels of disease-related disability compared to White Americans (Marrie et al., 2006). Comorbidities such as depression and anxiety, which are underdiagnosed and undertreated in this population, negatively impact quality of life and treatment outcomes for people living with multiple sclerosis (plwMS) (D'Alisa et al., 2006; Marrie et al., 2009; Stepleman et al., 2014). Acts of discrimination toward Black Americans is associated with stress, which is a contributing factor for depression (Carter, 2017; Nadimpalli, 2015; Williams and Mohammed, 2009). This study compared the severity of multiple sclerosis symptoms amongst Black Americans and White Americans, and whether worsened MS symptoms in Black Americans are associated with increased experiences of discrimination. Data was analyzed from 143 plwMS in the Stress Indicators in Minorities with Multiple Sclerosis (SiMMS) study. Using the Mann-Whitney U test, significant differences were found on the NIH Emotional Distress - Anxiety measure (U = 1466.500, p = 0.045) and NIH Sleep Disturbance measure (U = 1467.000, p = 0.044) between the Black participant and the White participant groups. Discrimination was significantly correlated with both NIH Emotional Distress - Anxiety (r = 0.677, p < .001) and NIH Sleep Disturbance (r = 0.446, p = .007) in Black MS individuals. Additionally, several physiological condition and psychological outcome measures were correlated with the NIH Emotional Distress - Anxiety and NIH Sleep Disturbance measures. This study contributes to literature highlighting the negative impacts of discrimination and race related stress on the physical and mental health of Black Americans.

Two C18 hydroxy-cyclohexenone fatty acids from mammalian epidermis: Potential relation to 12R-lipoxygenase and covalent binding of ceramides

A key requirement in forming the water permeability barrier in the mammalian epidermis is the oxidation of linoleate esterified in a skin-specific acylceramide by the sequential actions of 12R-lipoxygenase, epidermal lipoxygenase-3, and the epoxyalcohol dehydrogenase SDR9C7 (short-chain dehydrogenase-reductase family 7 member 9). By mechanisms that remain unclear, this oxidation pathway promotes the covalent binding of ceramides to protein, forming a critical structure of the epidermal barrier, the corneocyte lipid envelope. Here, we detected, in porcine, mouse, and human epidermis, two novel fatty acid derivatives formed by KOH treatment from precursors covalently bound to protein: a "polar" lipid chromatographing on normal-phase HPLC just before omega-hydroxy ceramide and a "less polar" lipid nearer the solvent front. Approximately 100 μg of the novel lipids were isolated from porcine epidermis, and the structures were established by UV-spectroscopy, LC-MS, GC-MS, and NMR. Each is a C18 fatty acid and hydroxy-cyclohexenone with the ring on carbons C9-C14 in the polar lipid and C8-C13 in the less polar lipid. Overnight culture of [14C]linoleic acid with whole mouse skin ex vivo led to recovery of the 14C-labeled hydroxy-cyclohexenones. We deduce they are formed from covalently bound precursors during the KOH treatment used to release esterified lipids. KOH-induced intramolecular aldol reactions from a common precursor can account for their formation. Discovery of these hydroxy-cyclohexenones presents an opportunity for a reverse pathway analysis, namely to work back from these structures to identify their covalently bound precursors and relationship to the linoleate oxidation pathway.

Recombinant PNPLA1 catalyzes the synthesis of acylceramides and acyl acids with selective incorporation of linoleic acid

Loss-of-function mutations in patatin-like phospholipase domain-containing protein 1 (PNPLA1) cause autosomal recessive congenital ichthyosis, and altered PNPLA1 activity is implicated in the pathogenesis of atopic dermatitis and other common skin diseases. To examine the hypothesis that PNPLA1 catalyzes the synthesis of acylceramides and acyl acids, we expressed and partially purified a soluble, truncated form of PNPLA1 in Escherichia coli, (PNPLA1trun) along with the related protein PNPLA2 (ATGL, adipose triglyceride lipase) and coactivator CGI-58. Liposomal substrates were incubated with recombinant enzymes for 0.5-24 h and products analyzed by HPLC-UV and LC-MS. Using trilinolein or dilinolein substrates, PNPLA1trun, like ATGLtrun, catalyzed lipolysis and acyltransferase reactions with 2-30% conversion into linoleic acid, monolinolein, and trilinolein. CGI-58 enhanced ATGL-catalyzed lipolysis as previously reported, but transacylase activity was not enhanced with ATGL or PNPLA1. In matching the proposed activity in vivo, PNPLA1 catalyzed acyl transfer from trilinolein and dilinolein donors to omega-hydroxy ceramide, omega-hydroxy glucosylceramide, and omega-hydroxy acid acceptors to form acylceramide, glucosyl-acylceramide, and acyl acid, respectively, albeit with only ∼0.05% conversion of the substrates. Notably, in experiments comparing dilinolein vs. diolein acyl donors, PNPLA1 transferred linoleate with 3:1 selectivity over oleate into acylceramide. These results support the role for PNPLA1 in the synthesis of acylceramides and acyl acids in epidermis and suggest that the enrichment of these lipids with linoleic acid could result from the substrate selectivity of PNPLA1.

FLG Deficiency in Mice Alters the Early-Life CD4+ T-Cell Response to Skin Commensal Bacteria

FLG variants underlie ichthyosis vulgaris and increased risk of atopic dermatitis, conditions typified by disruption of the skin microbiome and cutaneous immune response. Yet, it remains unclear whether neonatal skin barrier compromise because of FLG deficiency alters the quality of commensal-specific T cells and the functional impact of such responses. To address these questions, we profiled changes in the skin barrier and early cutaneous immune response of neonatal C57BL/6 Flg^‒/‒ and wild-type mice using single-cell RNA sequencing, flow cytometry, and other modalities. Flg^‒/‒ neonates showed little alteration in transepidermal water loss or lipid- or corneocyte-related gene expression. However, they showed increases in barrier disruption genes, epidermal dye penetration, and numbers of skin CD4⁺ T cells. Using an engineered strain of Staphylococcus epidermidis (S. epidermidis 2W) to study the response to neonatal skin colonization, we found that commensal-specific CD4⁺ T cells were skewed in Flg^‒/‒ pups toward effector rather than regulatory T cells. This altered response persisted into adulthood, where it was typified by T helper 17 (Th17) cells and associated with increased susceptibility to imiquimod-induced skin inflammation. Thus, subtle but impactful differences in neonatal barrier function in Flg^‒/‒ mice are accompanied by a skewed commensal-specific CD4⁺ response, with enduring consequences for skin immune homeostasis.

ω-O-Acylceramides but not ω-hydroxy ceramides are required for healthy lamellar phase architecture of skin barrier lipids

Epidermal omega-O-acylceramides (ω-O-acylCers) are essential components of a competent skin barrier. These unusual sphingolipids with ultralong N-acyl chains contain linoleic acid esterified to the terminal hydroxyl of the N-acyl, the formation of which requires the transacylase activity of patatin-like phospholipase domain containing 1 (PNPLA1). In ichthyosis with dysfunctional PNPLA1, ω-O-acylCer levels are significantly decreased, and ω-hydroxylated Cers (ω-OHCers) accumulate. Here we explore the role of the linoleate moiety in ω-O-acylCers in the assembly of the skin lipid barrier. Ultrastructural studies of skin samples from neonatal Pnpla1^+/+ and Pnpla1^-/- mice showed that the linoleate moiety in ω-O-acylCers is essential for lamellar pairing in lamellar bodies, as well as for stratum corneum lipid assembly into the long periodicity lamellar phase (LPP). To further study the molecular details of ω-O-acylCer deficiency on skin barrier lipid assembly, we built in vitro lipid models composed of major stratum corneum lipid subclasses containing either ω-O-acylCer (healthy skin model), ω-OHCer (Pnpla1^-/- model), or combination of the two. X-ray diffraction, infrared spectroscopy, and permeability studies indicated that ω-OHCers could not substitute for ω-O-acylCers, although in favorable conditions, they form a medium lamellar phase with a 10.8 nm-repeat distance and permeability barrier properties similar to LPP. In the absence of ω-O-acylCers, skin lipids were prone to separation into two phases with diminished barrier properties. The models combining ω-OHCers with ω-O-acylCers indicated that accumulation of ω-OHCers does not prevent ω-O-acylCer-driven lamellar stacking. These data suggest that ω-O-acylCer supplementation may be a viable therapeutic option in patients with PNPLA1 deficiency.

Engineering of Cry3Bb1 provides mechanistic insights toward countering western corn rootworm resistance

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Cry3Bb1 engineering for receptor retargeting to counter WCR resistance described

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Phage display screens against BBMV or recombinant insecticidal-protein receptors

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77 gut binding peptides selected and engineered into 284 new variants of Cry3Bb1

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112 variants were active against susceptible but not resistant WCR

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Engineering of Cry3Bb1 Domain II loops 1 and 2 disrupted insecticidal activity

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Sites for Cry3Bb1 engineering and implications for Cry3Bb1 resistance discussed

The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is an economically important pest of corn (maize) in North America and Europe. Current management practices for WCR involve transgenic expression of insecticidal proteins to minimize larval feeding damage to corn roots. The evolution of resistant WCR populations to transgenic corn expressing insecticidal proteins (e.g. Cry3Bb1, Gpp34Ab1/Tpp35Ab1) necessitates efforts to discover and deploy new modes of action for WCR control. Here, we tested the hypothesis that the addition of short peptides selected for binding to the WCR gut would restore insecticidal activity of Cry3Bb1 to resistant insects. Phage display technology coupled with deep sequencing was used to identify peptides selected for binding to WCR brush border membrane vesicles and to recombinant putative receptors aminopeptidase and cadherin. The binding and specificity of selected peptides was confirmed by ELISA and pull-down assays, and candidate gut surface binding partners were identified. Although production of 284 novel Cry3Bb1 variants with these peptides did not restore activity against resistant WCR in artificial diet bioassays, 112 variants were active against susceptible insects. These results provided insights for the mechanism of Cry3Bb1 activity and toward engineering a new mode-of-action via receptor re-targeting in the context of protein structure and function.

Phenotypic overlap between atopic dermatitis and autism

BACKGROUND

Autism, a childhood behavioral disorder, belongs to a large suite of diseases, collectively referred to as autism spectrum disorders (ASD). Though multifactorial in etiology, approximately 10% of ASD are associated with atopic dermatitis (AD). Moreover, ASD prevalence increases further as AD severity worsens, though these disorders share no common causative mutations. We assessed here the link between these two disorders in the standard, valproic acid mouse model of ASD. In prior studies, there was no evidence of skin involvement, but we hypothesized that cutaneous involvement could be detected in experiments conducted in BALB/c mice. BALB/c is an albino, laboratory-bred strain of the house mouse and is among the most widely used inbred strains used in animal experimentation.

METHODS

We performed our studies in valproic acid (VPA)-treated BALB/c hairless mice, a standard mouse model of ASD. Mid-trimester pregnant mice received a single intraperitoneal injection of either valproic acid sodium salt dissolved in saline or saline alone on embryonic day 12.5 and were housed individually until postnatal day 21. Only the brain and epidermis appeared to be affected, while other tissues remain unchanged. At various postnatal time points, brain, skin and blood samples were obtained for histology and for quantitation of tissue sphingolipid content and cytokine levels.

RESULTS

AD-like changes in ceramide content occurred by day one postpartum in both VPA-treated mouse skin and brain. The temporal co-emergence of AD and ASD, and the AD phenotype-dependent increase in ASD prevalence correlated with early appearance of cytokine markers (i.e., interleukin [IL]-4, 5, and 13), as well as mast cells in skin and brain. The high levels of interferon (IFN)γ not only in skin, but also in brain likely account for a significant decline in esterified very-long-chain N-acyl fatty acids in brain ceramides, again mimicking known IFNγ-induced changes in AD.

CONCLUSION

Baseline involvement of both AD and ASD could reflect concurrent neuro- and epidermal toxicity, possibly because both epidermis and neural tissues originate from the embryonic neuroectoderm. These studies illuminate the shared susceptibility of the brain and epidermis to a known neurotoxin, suggesting that the atopic diathesis could be extended to include ASD.

Unbound Corneocyte Lipid Envelopes in 12R-Lipoxygenase Deficiency Support a Specific Role in Lipid-Protein Cross-Linking

Loss-of-function mutations in arachidonate lipoxygenase 12B (ALOX12B) are an important cause of autosomal recessive congenital ichthyosis (ARCI). 12R-lipoxygenase (12R-LOX), the protein product of ALOX12B, has been proposed to covalently bind the corneocyte lipid envelope (CLE) to the proteinaceous corneocyte envelope, thereby providing a scaffold for the assembly of barrier-providing, mature lipid lamellae. To test this hypothesis, an in-depth ultrastructural examination of CLEs was performed in ALOX12B^-/- human and Alox12b^-/- mouse epidermis, extracting samples with pyridine to distinguish covalently attached CLEs from unbound (ie, noncovalently bound) CLEs. ALOX12B^--/- stratum corneum contained abundant pyridine-extractable (ie, unbound) CLEs, compared with normal stratum corneum. These unbound CLEs were associated with defective post-secretory lipid processing, and were specific to 12R-LOX deficiency, because they were not observed with deficiency of the related ARCI-associated proteins, patatin-like phospholipase 1 (Pnpla1) or abhydrolase domain containing 5 (Abhd5). These results suggest that 12R-LOX contributes specifically to CLE-corneocyte envelope cross-linking, which appears to be a prerequisite for post-secretory lipid processing, and provide insights into the pathogenesis of 12R-LOX deficiency in this subtype of ARCI, as well as other conditions that display a defective CLE.

CERKL is upregulated in cutaneous squamous cell carcinoma and maintains cellular sphingolipids and resistance to oxidative stress

BACKGROUND

Ceramide kinase-like protein (CERKL) was originally described in retinal tissue. CERKL has been shown to protect cells from oxidative stress, and mutations in CERKL underlie the inherited disease retinitis pigmentosa. CERKL expression maintains cellular sphingolipids via an unknown mechanism.

OBJECTIVES

To determine whether CERKL is expressed in epidermis and cutaneous squamous cell carcinoma (cSCC) and whether CERKL expression affects cSCC sphingolipid metabolism and susceptibility to oxidative stress.

METHODS

CERKL expression was determined by RNA-Seq, quantitative polymerase chain reaction and immunohistochemistry. CERKL was knocked down in cSCC cells using small interfering RNA. Sphingolipid content was analysed by liquid chromatography-mass spectrometry. Oxidative stress was induced by treatment with H₂ O₂ , and apoptosis was measured using flow cytometry to determine annexin V binding.

RESULTS

CERKL mRNA and protein are highly expressed in actinic keratosis and cSCC in comparison with normal epidermis. CERKL is also expressed in metabolically active epithelial cells in normal hair bulbs and sebaceous glands. CERKL knockdown in cultured cSCC cells reduces cellular sphingolipid content and enhances susceptibility to oxidative stress.

CONCLUSIONS

These findings suggest that CERKL may be important in cSCC progression and could lead to novel strategies for prevention and treatment of cSCC.

CERKL is Upregulated in Cutaneous Squamous Cell Carcinoma and Maintains Cellular Sphingolipids and Resistance to Oxidative Stress

BACKGROUND

Ceramide Kinase-Like Protein (CERKL) was originally described in retinal tissue. CERKL has been shown to protect cells from oxidative stress, and mutations in CERKL underlie the inherited disease, retinitis pigmentosa. CERKL expression maintains cellular sphingolipids via an unknown mechanism.

OBJECTIVES

To determine whether CERKL is expressed in epidermis and cutaneous squamous cell carcinoma (cSCC) and whether CERKL expression affects cSCC sphingolipid metabolism and susceptibility to oxidative stress.

METHODS

CERKL expression was determined by RNA-Seq, qPCR and immunohistochemistry. CERKL was knocked down in cSCC cells using siRNA. Sphingolipid content was analyzed by liquid chromatography-mass spectrometry (LC-MS). Oxidative stress was induced by treatment with H2 O2 , and apoptosis was measured using flow cytometry to determine annexin v binding.

RESULTS

CERKL mRNA and protein are highly expressed in actinic keratosis and cSCC in comparison with normal epidermis. CERKL also is expressed in metabolically active epithelial cells in normal hair bulbs and sebaceous glands. CERKL knockdown in cultured cSCC cells reduces cellular sphingolipid content and enhances susceptibility to oxidative stress.

CONCLUSIONS

These findings suggest that CERKL may be important in cSCC progression and could lead to novel strategies for prevention and treatment of cSCC.

Exosomes from Human Adipose Tissue-Derived Mesenchymal Stem Cells Promote Epidermal Barrier Repair by Inducing de Novo Synthesis of Ceramides in Atopic Dermatitis

Atopic dermatitis (AD) is a multifactorial, heterogeneous disease associated with epidermal barrier disruption and intense systemic inflammation. Previously, we showed that exosomes derived from human adipose tissue-derived mesenchymal stem cells (ASC-exosomes) attenuate AD-like symptoms by reducing multiple inflammatory cytokine levels. Here, we investigated ASC-exosomes' effects on skin barrier restoration by analyzing protein and lipid contents. We found that subcutaneous injection of ASC-exosomes in an oxazolone-induced dermatitis model remarkably reduced trans-epidermal water loss, while enhancing stratum corneum (SC) hydration and markedly decreasing the levels of inflammatory cytokines such as IL-4, IL-5, IL-13, TNF-α, IFN-γ, IL-17, and TSLP, all in a dose-dependent manner. Interestingly, ASC-exosomes induced the production of ceramides and dihydroceramides. Electron microscopic analysis revealed enhanced epidermal lamellar bodies and formation of lamellar layer at the interface of the SC and stratum granulosum with ASC-exosomes treatment. Deep RNA sequencing analysis of skin lesions demonstrated that ASC-exosomes restores the expression of genes involved in skin barrier, lipid metabolism, cell cycle, and inflammatory response in the diseased area. Collectively, our results suggest that ASC-exosomes effectively restore epidermal barrier functions in AD by facilitating the de novo synthesis of ceramides, resulting in a promising cell-free therapeutic option for treating AD.

Endoplasmic Reticulum Calcium Regulates Epidermal Barrier Response and Desmosomal Structure

Ca(2+) fluxes direct keratinocyte differentiation, cell-to-cell adhesion, migration, and epidermal barrier homeostasis. We previously showed that intracellular Ca(2+) stores constitute a major portion of the calcium gradient especially in the stratum granulosum. Loss of the calcium gradient triggers epidermal barrier homeostatic responses. In this report, using unfixed ex vivo epidermis and human epidermal equivalents we show that endoplasmic reticulum (ER) Ca(2+) is released in response to barrier perturbation, and that this release constitutes the major shift in epidermal Ca(2+) seen after barrier perturbation. We find that ER Ca(2+) release correlates with a transient increase in extracellular Ca(2+). Lastly, we show that ER calcium release resulting from barrier perturbation triggers transient desmosomal remodeling, seen as an increase in extracellular space and a loss of the desmosomal intercellular midline. Topical application of thapsigargin, which inhibits the ER Ca(2+) ATPase activity without compromising barrier integrity, also leads to desmosomal remodeling and loss of the midline structure. These experiments establish the ER Ca(2+) store as a master regulator of the Ca(2+) gradient response to epidermal barrier perturbation, and suggest that ER Ca(2+) homeostasis also modulates normal desmosomal reorganization, both at rest and after acute barrier perturbation.

Comparative pharmacological characterization of D1-like dopamine receptors from Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus suggests pleiotropic signaling in mosquito vector lineages

Background

Small molecule antagonists of mosquito dopamine receptors (DARs) are under investigation as a new class of vector-selective insecticides. Antagonists that inhibit the D₁-like DARs AaDOP2 and CqDOP2 from the mosquitoes Aedes aegypti L. and Culex quinquefasciatus Say, respectively, also cause larval mortality in bioassays. Here, we report on the orthologous DAR, AgDOP2, from the malaria mosquito Anopheles gambiae Giles that was cloned and pharmacologically characterized in HEK293 cells. Larval bioassays were then conducted to examine the potential of DAR antagonist insecticides against Anopheles vectors.

Findings

Previous in vitro cAMP accumulation assays demonstrated Gαs coupling for AaDOP2 and CqDOP2 and dose-dependent inhibition by DAR antagonists. We observed a negligible response of AgDOP2 in the cAMP assay, which prompted an investigation of alternative coupling for mosquito DARs. In an in vitro IP-One Gα_q second messenger assay of calcium signaling, dopamine stimulation increased IP1 accumulation in AaDOP2-, CqDOP2- and AgDOP2-expressing cells, and DAR antagonists inhibited IP1 signaling in a dose-dependent manner. In larval bioassays, DAR antagonists caused considerable mortality of An. gambiae larvae within 24 h post-exposure.

Conclusions

In vitro data reveal pleiotropic coupling of AaDOP2 and CqDOP2 to Gα_q and Gα_s. In contrast, AgDOP2 appeared to selectively couple to Gαq signaling. In vitro antagonist studies revealed general conservation in pharmacology between mosquito DARs. In vivo data suggest potential for DAR antagonist insecticides against An. gambiae. Sequence conservation among the DOP2 receptors from 15 Anopheles species indicates utility of antagonists to control residual malaria transmission. AgDOP2 Gα_q-dependent signaling could be exploited for An. gambiae control via pathway specific antagonists.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-016-1477-6) contains supplementary material, which is available to authorized users.

Genomic insights into the Ixodes scapularis tick vector of Lyme disease

Ticks transmit more pathogens to humans and animals than any other arthropod. We describe the 2.1 Gbp nuclear genome of the tick, Ixodes scapularis (Say), which vectors pathogens that cause Lyme disease, human granulocytic anaplasmosis, babesiosis and other diseases. The large genome reflects accumulation of repetitive DNA, new lineages of retro-transposons, and gene architecture patterns resembling ancient metazoans rather than pancrustaceans. Annotation of scaffolds representing ∼57% of the genome, reveals 20,486 protein-coding genes and expansions of gene families associated with tick-host interactions. We report insights from genome analyses into parasitic processes unique to ticks, including host 'questing', prolonged feeding, cuticle synthesis, blood meal concentration, novel methods of haemoglobin digestion, haem detoxification, vitellogenesis and prolonged off-host survival. We identify proteins associated with the agent of human granulocytic anaplasmosis, an emerging disease, and the encephalitis-causing Langat virus, and a population structure correlated to life-history traits and transmission of the Lyme disease agent.

Dopamine receptor antagonists as new mode-of-action insecticide leads for control of Aedes and Culex mosquito vectors

Background

New mode-of-action insecticides are sought to provide continued control of pesticide resistant arthropod vectors of neglected tropical diseases (NTDs). We previously identified antagonists of the AaDOP2 D1-like dopamine receptor (DAR) from the yellow fever mosquito, Aedes aegypti, with toxicity to Ae. aegypti larvae as leads for novel insecticides. To extend DAR-based insecticide discovery, we evaluated the molecular and pharmacological characteristics of an orthologous DAR target, CqDOP2, from Culex quinquefasciatus, the vector of lymphatic filariasis and West Nile virus.

Methods/Results

CqDOP2 has 94.7% amino acid identity to AaDOP2 and 28.3% identity to the human D1-like DAR, hD1. CqDOP2 and AaDOP2 exhibited similar pharmacological responses to biogenic amines and DAR antagonists in cell-based assays. The antagonists amitriptyline, amperozide, asenapine, chlorpromazine and doxepin were between 35 to 227-fold more selective at inhibiting the response of CqDOP2 and AaDOP2 in comparison to hD1. Antagonists were toxic to both C. quinquefasciatus and Ae. aegypti larvae, with LC50 values ranging from 41 to 208 μM 72 h post-exposure. Orthologous DOP2 receptors identified from the African malaria mosquito, Anopheles gambiae, the sand fly, Phlebotomus papatasi and the tsetse fly, Glossina morsitans, had high sequence similarity to CqDOP2 and AaDOP2.

Conclusions

DAR antagonists represent a putative new insecticide class with activity against C. quinquefasciatus and Ae. aegypti, the two most important mosquito vectors of NTDs. There has been limited change in the sequence and pharmacological properties of the DOP2 DARs of these species since divergence of the tribes Culicini and Aedini. We identified antagonists selective for mosquito versus human DARs and observed a correlation between DAR pharmacology and the in vivo larval toxicity of antagonists. These data demonstrate that sequence similarity can be predictive of target potential. On this basis, we propose expanded insecticide discovery around orthologous DOP2 targets from additional dipteran vectors.

New mode-of-action insecticides are required to control arthropod vectors of neglected tropical diseases (NTDs). Rational drug design approaches offer attractive methods to identify new insecticidal chemistries that are potent and selective for molecular targets of arthropod vectors. Previously identified antagonists of a D₁-like dopamine receptor (DAR) from the yellow fever mosquito, Aedes aegypti were toxic to the larvae of this species and are candidate novel insecticide leads. Building on this work, here we evaluated the molecular and pharmacological characteristics of an orthologous DAR from Culex quinquefasciatus, the vector of lymphatic filariasis and West Nile virus. We show that orthologous mosquito DARs have similar pharmacological profiles in vitro and that Ae. aegypti-active DAR antagonists are toxic to C. quinquefasciatus larvae in vivo. Sequence similarity between orthologous targets can be indicative of DAR target potential for discovery of potent, selective inhibitors. These findings justify expansion of insecticide discovery efforts to orthologous DARs from additional dipteran vectors of NTDs and provide support for DAR antagonists as a new class of chemistries for taxon-selective insecticides for vector control.

Evaluation of AaDOP2 receptor antagonists reveals antidepressants and antipsychotics as novel lead molecules for control of the yellow fever mosquito, Aedes aegypti

The yellow fever mosquito, Aedes aegypti, vectors disease-causing agents that adversely affect human health, most notably the viruses causing dengue and yellow fever. The efficacy of current mosquito control programs is challenged by the emergence of insecticide-resistant mosquito populations, suggesting an urgent need for the development of chemical insecticides with new mechanisms of action. One recently identified potential insecticide target is the A. aegypti D1-like dopamine receptor, AaDOP2. The focus of the present study was to evaluate AaDOP2 antagonism both in vitro and in vivo using assay technologies with increased throughput. The in vitro assays revealed AaDOP2 antagonism by four distinct chemical scaffolds from tricyclic antidepressant or antipsychotic chemical classes, and elucidated several structure-activity relationship trends that contributed to enhanced antagonist potency, including lipophilicity, halide substitution on the tricyclic core, and conformational rigidity. Six compounds displayed previously unparalleled potency for in vitro AaDOP2 antagonism, and among these, asenapine, methiothepin, and cis-(Z)-flupenthixol displayed subnanomolar IC50 values and caused rapid toxicity to A. aegypti larvae and/or adults in vivo. Our study revealed a significant correlation between in vitro potency for AaDOP2 antagonism and in vivo toxicity, suggesting viability of AaDOP2 as an insecticidal target. Taken together, this study expanded the repertoire of known AaDOP2 antagonists, enhanced our understanding of AaDOP2 pharmacology, provided further support for rational targeting of AaDOP2, and demonstrated the utility of efficiency-enhancing in vitro and in vivo assay technologies within our genome-to-lead pipeline for the discovery of next-generation insecticides.

An Isopyoverdin from Pseudomonas putida CFML 90-44

From Pseudomonas putida CFML 90-44 an isopyoverdin was isolated. Its structure could be elucidated by chemical degradation and spectroscopic data.

Minimally oxidized LDL inhibits macrophage selective cholesteryl ester uptake and native LDL-induced foam cell formation

Scavenger receptor-mediated uptake of oxidized LDL (oxLDL) is thought to be the major mechanism of foam cell generation in atherosclerotic lesions. Recent data has indicated that native LDL is also capable of contributing to foam cell formation via low-affinity receptor-independent LDL particle pinocytosis and selective cholesteryl ester (CE) uptake. In the current investigation, Cu(2+)-induced LDL oxidation was found to inhibit macrophage selective CE uptake. Impairment of selective CE uptake was significant with LDL oxidized for as little as 30 min and correlated with oxidative fragmentation of apoB. In contrast, LDL aggregation, LDL CE oxidation, and the enhancement of scavenger receptor-mediated LDL particle uptake required at least 3 h of oxidation. Selective CE uptake did not require expression of the LDL receptor (LDL-R) and was inhibited similarly by LDL oxidation in LDL-R(-/-) versus WT macrophages. Inhibition of selective uptake was also observed when cells were pretreated or cotreated with minimally oxidized LDL, indicating a direct inhibitory effect of this oxLDL on macrophages. Consistent with the effect on LDL CE uptake, minimal LDL oxidation almost completely prevented LDL-induced foam cell formation. These data demonstrate a novel inhibitory effect of mildly oxidized LDL that may reduce foam cell formation in atherosclerosis.

Significance of saguaro cactus alkaloids in ecology ofDrosophila mettleri, a soil-breeding, cactophilic drosophilid

Drosophila mettleri is a soil-breeding, cactophilic drosophilid which lives in the Sonoran Desert. Several chemical constituents of cacti in this region have been identified as having major roles in insect-host plant relationships involvingDrosophila. For example, isoquinoline alkaloids, which are present in senita cactus, have been shown to be toxic to seven of the nine species tested. The two tolerant species areD. pachea, the normal resident, andD. mettleri. Necroses of senita cacti are often used as feeding substrates byD. mettleri adults, but this species has never been reared from senita rots. Soil, which have been soaked by juice from saguaro and cardón rots, are the typical breeding substrates of this species. The tissues of both of these cacti also contain alkaloids, chemically related to those in senita, but at much lower concentrations. Alkaloid concentration in saguaro-soaked soil was found to be 1.4-27 times the average concentration in fresh tissue. Alkaloids were extracted from saguaro tissue and used in tests of larva-to-adult viability, developmental rate, and adult longevity. Elevated concentrations of saguaro alkaloids had no significant effect on the longevity ofD. mettleri, but significantly reduced the longevity ofD. nigrospiracula andD. mojavensis, two nonsoil breeding cactophilic species. Viability and developmental rates of all three species were affected, but the effect onD. nigrospiracula was comparatively greater. It is argued that the adaptations that allowD. mettleri to utilize the saguaro soil niche also convey tolerance to alkaloids present in senita tissue. The ability to utilize senita necroses as feeding substrates represents an ecological advantage to D. mettleri, in that the density of potential feeding sites is increased as compared to species which are more specific in their host-plant relationships.

New developments in selective cholesteryl ester uptake

PURPOSE OF REVIEW

Selective lipid uptake (SLU) is known to be a major pathway of lipoprotein cholesterol metabolism in experimental animals and humans, but remains poorly understood. This review provides a brief overview of SLU mediated by the HDL receptor scavenger receptor B-type I (SR-BI), and highlights several surprising new findings related to the impact of SLU pathways in cholesterol homeostasis.

RECENT FINDINGS

Under certain conditions, SR-BI-mediated SLU contributes to reverse cholesterol transport (RCT) independently of ABCG5/G8-mediated biliary cholesterol secretion, implying a novel trafficking mechanism. Hepatic SR-BI expression and RCT are decreased in diabetic mice. Farnesoid X receptor (FXR) and the microRNAs miR-185, miR-96 and miR-223 are emerging therapeutic targets for increasing SR-BI expression. SR-BI-independent selective cholesteryl ester uptake is a newly characterized pathway in macrophage foam cells.

SUMMARY

New findings underscore the importance of SR-BI-mediated SLU in hepatic SLU and RCT, while indicating that further investigation is needed to define SLU pathways, including SR-BI-independent macrophage selective cholesteryl ester uptake. The intracellular trafficking of cholesterol in these pathways appears to be critical to their normal function and is a major subject of ongoing studies.

Abstract 408: Macrophage-mediated Low Density Lipoprotein Modification Reduces Foam Cell Formation

Macrophage metabolism of LDL-derived cholesterol is thought to be a key process regulating the composition and progression of atherosclerotic lesions, including the generation of cholesterol-loaded macrophage foam cells and the lipid-rich necrotic core. Many mechanisms contribute to macrophage endocytosis of LDL, and we recently reported that selective cholesteryl ester (CE) uptake contributes to LDL-induced macrophage cholesterol accumulation. Selective uptake is expected to result in the net removal of cholesteryl ester from LDL; however, the effect of this and other LDL modifications that may occur during incubation with macrophages is not understood. In the current investigation, we pre-incubated LDL for 1-2 days with macrophages in order to promote macrophage-mediated LDL modification. Surprisingly, when macrophage-conditioned LDL was transferred to fresh macrophages, much less cholesterol accumulation resulted compared to cells incubated with unconditioned LDL, as indicated by cholesterol quantification and by neutral lipid staining with Oil Red-O. This difference was not accounted for by changes in uptake of the modified 125I-LDLs, but instead was associated with a large decrease in selective [3H]CE uptake. In contrast, uptake of the non-hydrolyzable CE analog [3H]cholesteryl ether was not reduced, suggesting that reduced uptake in macrophage-conditioned LDL may be due to changes in the hydrolysis of LDL-derived CE or its subsequent metabolism. Cell-mediated LDL oxidation was considered as a possible mechanism for changes in selective CE uptake. However, agarose gel electrophoretic mobility of LDL and analysis of LDL cholesteryl esters indicated that reduced selective uptake and foam cell formation did not depend on extensive oxidative modifications of LDL. These results indicate the importance of selective CE and suggest that macrophage-mediated LDL modification may reduce foam cell formation in some circumstances.

Transcriptome sequencing and annotation of the predatory mite Metaseiulus occidentalis (Acari: Phytoseiidae): a cautionary tale about possible contamination by prey sequences

Next-generation sequencing was applied to the transcriptome of the phytoseiid Metaseiulus occidentalis to characterize gene expression in all life stages reared under different conditions to optimize the recovery of as many genes as possible. One production and one titration run produced a total of 862,069 reads (average size: 314.87 bp), which generated 255.6 Mbp of sequences on the GS-FLX Titanium sequencing platform. After removal of putative prey sequences 850,543 reads were used in NewBler and PTA assemblies to produce 74,172 non-redundant sequences, including 30,691 contigs and 43,481 singlets with 11,994 contigs consisting of more than 500 bp and 37,278 sequences >300 bp, constituting 48.7 % of all sequences. There were 25,888 hits with the NCBI non-redundant database and 15,376 unique transcripts. There were 26,225 hits with the Ixodes scapularis genome and 6,634 unique transcripts. There were 22,225 hits with the RefSeq of Homo sapiens with 6,465 unique transcripts, and 23,656 hits with the RefSeq of Drosophila melanogaster with 9,216 unique transcripts. Selected ESTs corresponding to genes of interest were analyzed including those related to transposable elements, GPCRs, Sox transcription factors, diapause and foraging behavior, and pesticide resistances. Novel and important genes appear to have been discovered that provide insight into the evolution, biology, and physiology of this important predator of pest mites in agriculture and will be useful in analyzing complete genome sequences of this natural enemy.

Discovery of antagonists of tick dopamine receptors via chemical library screening and comparative pharmacological analyses

Ticks transmit a wide variety of disease causing pathogens to humans and animals. Considering the global health impact of tick-borne diseases, there is a pressing need to develop new methods for vector control. We are exploring arthropod dopamine receptors as novel targets for insecticide/acaricide development because of their integral roles in neurobiology. Herein, we developed a screening assay for dopamine receptor antagonists to further characterize the pharmacological properties of the two D₁-like dopamine receptors (Isdop1 and Isdop2) identified in the Lyme disease vector, Ixodes scapularis, and develop a screening assay for receptor antagonists. A cell-based, cyclic AMP luciferase reporter assay platform was implemented to screen the LOPAC(1280) small molecule library for Isdop2 receptor antagonists, representing the first reported chemical library screen for any tick G protein-coupled receptor. Screening resulted in the identification of 85 "hit" compounds with antagonist activity at the Isdop2 receptor. Eight of these chemistries were selected for confirmation assays using a direct measurement of cAMP, and the effects on both Isdop1 and Isdop2 were studied for comparison. Each of these eight compounds showed antagonistic activity at both Isdop1 and Isdop2, although differences were observed regarding their relative potencies. Furthermore, comparison of the pharmacological properties of the tick dopamine receptors with that of the AaDOP2 receptor from the yellow fever mosquito and the human dopamine D₁ receptor (hD₁) revealed species-specific pharmacological profiles of these receptors. Compounds influencing dopaminergic functioning, such as the dopamine receptor antagonists discovered here, may provide lead chemistries for discovery of novel acaricides useful for vector control

High-capacity selective uptake of cholesteryl ester from native LDL during macrophage foam cell formation

Macrophage foam cells are a defining pathologic feature of atherosclerotic lesions. Recent studies have demonstrated that at high concentrations associated with hypercholesterolemia, native LDL induces macrophage lipid accumulation. LDL particles are taken up by macrophages as part of bulk fluid pinocytosis. However, the uptake and metabolism of cholesterol from native LDL during foam cell formation has not been clearly defined. Previous reports have suggested that selective cholesteryl ester (CE) uptake might contribute to cholesterol uptake from LDL independently of particle endocytosis. In this study we demonstrate that the majority of macrophage LDL-derived cholesterol is acquired by selective CE uptake in excess of LDL pinocytosis and degradation. Macrophage selective CE uptake does not saturate at high LDL concentrations and is not down-regulated during cholesterol accumulation. In contrast to CE uptake, macrophages exhibit little selective uptake of free cholesterol (FC) from LDL. Following selective uptake from LDL, CE is rapidly hydrolyzed by a novel chloroquine-sensitive pathway. FC released from LDL-derived CE hydrolysis is largely effluxed from cells but also is subject to ACAT-mediated reesterification. These results indicate that selective CE uptake plays a major role in macrophage metabolism of LDL.

Chemical Characterization, Crossfeeding and Uptake Studies on Hydroxamate Siderophore of Alcaligenes faecalis

We report the production of two types of siderophores namely catecholate and hydroxamate in modified succinic acid medium (SM) from Alcaligenes faecalis. Two fractions of siderophores were purified on amberlite XAD, major fraction was hydroxamate type having a λ(max) at 224 nm and minor fraction appeared as catecholate with a λ(max) of 264 nm. The recovery yield obtained from major and minor fractions was 297 and 50 mg ml(-1) respectively. The IEF pattern of XAD-4 purified siderophore suggested the pI value of 6.5. Cross feeding studies revealed that A. faecalis accepts heterologous as well as self (hydroxamate) siderophore in both free and iron complexed forms however; the rate of siderophore uptake was more in case of siderophores complexed to iron. Siderophore iron uptake studies indicated the differences between hydroxamate siderophore of A. faecalis and Alc E, a siderophore of Alcaligenes eutrophus.

Macrophage SR-BI regulates LPS-induced pro-inflammatory signaling in mice and isolated macrophages

Scavenger receptor BI (SR-BI), an HDL receptor, plays a key role in reverse cholesterol transport. In mice, disruption of SR-BI results in hypersensitivity to lipopolysaccharide (LPS) and bacteria-induced septic shock due to adrenal insufficiency and abnormal hepatic pathogen clearance. In this study, we identify an anti-inflammatory role of macrophage SR-BI. Using bone marrow transplantation, we report an enhanced pro-inflammatory response to LPS in wild-type (WT) mice receiving SR-BI-null compared with WT bone marrow cells and a reduced response in SR-BI-null mice receiving WT compared with SR-BI-null cells. Although significant, SR-BI deficiency limited to bone marrow-derived cells promoted a relatively modest enhancement of the inflammatory response to LPS in mice compared with the effect of whole-body SR-BI deletion. Consistent with earlier findings, SR-BI-null primary macrophages exhibited a greater inflammatory cytokine response to LPS than control macro phages. In addition, we showed that overexpression of SR-BI in J774 macrophages attenuated the inflammatory response to LPS. The LPS-induced cytokine expression in both WT and SR-BI-null macrophages was dependent not only on NFκB as previously reported but also on JNK and P38 cell signaling pathways. The increased inflammatory signaling in SR-BI-null cells was not related to alterations in cellular cholesterol content. We conclude that SR-BI plays an important function in regulating the macrophage inflammatory response to LPS.

Abstract 283: Novel Mechanism of Low-Density Lipoprotein--Derived Cholesteryl Ester Uptake and Hydrolysis During Macrophage Foam Cell Formation

Macrophage foam cells are a defining pathologic feature of atherosclerotic lesions. Classically, scavenger receptor-mediated uptake of oxidized or enzyme-modified LDL is cited as a mechanism for foam cell formation. Recent studies have demonstrated that at high concentrations, native LDL can also induce macrophage lipid accumulation. LDL particles are taken up by macrophages as part of bulk fluid pinocytosis. However, the uptake and metabolism of cholesterol derived from native LDL during macrophage foam cell formation has not been clearly defined. Previous studies suggested that selective CE uptake might contribute to cholesterol uptake independently of LDL endocytosis. In this study we demonstrate that the majority of cholesterol taken up from LDL is acquired by selective CE uptake and not by pinocytosis and LDL degradation. CE uptake does not saturate at high LDL concentrations and is not down-regulated during cholesterol accumulation. LDL modification and scavenger receptors do not appear to play a major role in macrophage selective CE uptake. Following uptake from LDL, CE is rapidly hydrolyzed in macrophages by a novel chloroquine- and temperature-sensitive pathway. Our findings suggest that selective CE uptake plays a major role in macrophage cholesterol homeostasis during foam cell formation.

Anderson localization in a periodic photonic lattice with a disordered boundary

We investigate experimentally the light evolution inside a two-dimensional finite periodic array of weakly coupled optical waveguides with a disordered boundary. For a completely localized initial condition away from the surface, we find that the disordered boundary induces an asymptotic localization in the bulk, centered around the initial position of the input beam.

Molecular and pharmacological characterization of two D(1)-like dopamine receptors in the Lyme disease vector, Ixodes scapularis

Advancements in tick neurobiology may impact the development of acaricides to control those species that transmit human and animal diseases. Here, we report the first cloning and pharmacological characterization of two neurotransmitter binding G protein-coupled receptors in the Lyme disease (blacklegged) tick, Ixodes scapularis. The genes IscaGPRdop1 and IscaGPRdop2 were identified in the I. scapularis genome assembly and predicted as orthologs of previously characterized D(1)-like dopamine receptors in the fruit fly Drosophila melanogaster and honeybee Apis mellifera. Heterologous expression in HEK 293 cells demonstrated that each receptor functioned as a D(1)-like dopamine receptor because significant increases in levels of intracellular cyclic adenosine monophosphate (cAMP) were detected following dopamine treatment. Importantly, the receptors were distinct in their pharmacological properties regarding concentration-dependent response to dopamine, constitutive activity, and response to other biogenic amines. Exposure to a variety of dopamine receptor agonists and antagonists further demonstrated a D(1)-like pharmacology of these dopamine receptors and highlighted their differential activities in vitro.

Scavenger receptor SR-BI in macrophage lipid metabolism

OBJECTIVE

To investigate the mechanisms by which macrophage scavenger receptor BI (SR-BI) regulates macrophage cholesterol homeostasis and protects against atherosclerosis.

METHODS AND RESULTS

The expression and function of SR-BI was investigated in cultured mouse bone marrow-derived macrophages (BMM). SR-BI, the other scavenger receptors SRA and CD36 and the ATP-binding cassette transporters ABCA1 and ABCG1 were each distinctly regulated during BMM differentiation. SR-BI levels increased transiently to significant levels during culture. SR-BI expression in BMM was reversibly down-regulated by lipid loading with modified LDL; SR-BI was shown to be present both on the cell surface as well as intracellularly. BMM exhibited selective HDL CE uptake, however, this was not dependent on SR-BI or another potential candidate glycosylphosphatidylinositol anchored high density lipoprotein binding protein 1 (GPIHBP1). SR-BI played a significant role in facilitating bidirectional cholesterol flux in non lipid-loaded cells. SR-BI expression enhanced both cell cholesterol efflux and cholesterol influx from HDL, but did not lead to altered cellular cholesterol mass. SR-BI-dependent efflux occurred to larger HDL particles but not to smaller HDL(3). Following cholesterol loading, ABCA1 and ABCG1 were up-regulated and served as the major contributors to cholesterol efflux, while SR-BI expression was down-regulated.

CONCLUSION

Our results suggest that SR-BI plays a significant role in macrophage cholesterol flux that may partly account for its effects on atherogenesis.

The effect of sertindole on QTD and TPTE

OBJECTIVE

Recent research suggests that other surrogate markers than QTc, including QTc dispersion and Tpeak-Tend, may better correlate with cardiac arrhythmia risk. While sertindole significantly prolongs the QTc interval, the effects on other markers of arrhythmia risk, such as QTc dispersion and Tpeak-Tend are unknown.

METHOD

Digital 12-lead ECG was recorded at baseline and at steady-state in 37 patients switched to sertindole. ECG was analysed for Fridericia-corrected QT duration (QTcF), QT dispersion and Tpeak-Tend.

RESULTS

From a baseline QTcF of 407 +/- 22 ms, mean QTcF prolongation during sertindole treatment was 20 +/- 23 ms, P < 0.01. No effect on QTc dispersion was found (-1 +/- 11 ms; P = 0.41). No increased duration of the Tpeak-Tend interval from baseline was found (+7 +/- 21 ms; P = 0.05).

CONCLUSION

These findings might be related to the absence of confirmed Torsade de Pointes (TdP) cases related to sertindole exposure, despite sertindole's QTc prolonging effects.

Which comes first: atypical antipsychotic treatment or cardiometabolic risk?

OBJECTIVE

To provide an overview for practicing clinicians on the pharmacological basis of cardiometabolic risk induced by antipsychotic drugs in patients with serious mental illness, to propose hypotheses to explain these risks and to give tips for managing cardiometabolic risk during antipsychotic treatment.

METHOD

A MEDLINE search using terms for atypical antipsychotics (including individual drug names), metabolic, cardiovascular, weight gain and insulin resistance, cross-referenced with schizophrenia was performed on articles published between 1990 and May 2008.

RESULTS

Strong evidence exists for significant cardiometabolic risk differences among several antipsychotic agents. Histamine H1 and serotonin 5HT2C antagonism are associated with risk of weight gain, but receptor targets for dyslipidemia and insulin resistance have not yet been identified. Convincing data indicate that hypertriglyceridemia and insulin resistance may occur in the absence of weight gain with certain antipsychotics.

CONCLUSION

Although lifestyle and genetics may contribute independent risks of cardiometabolic dysfunction in schizophrenia and other serious mental illness, antipsychotic treatment also represents an important contributor to risk of cardiometabolic dysfunction, particularly for certain drugs and for vulnerable patients. Mental health professionals must learn to recognize the clinical signposts indicating antipsychotic-related cardiometabolic problems to forestall progression to type II diabetes, cardiovascular events and premature death.

The metabolic syndrome and schizophrenia

OBJECTIVE

To summarize the accumulated data on metabolic syndrome prevalence in patients with schizophrenia, examine evidence for a biological contribution of the mental illness to metabolic risk and review novel options available for management of prediabetic states.

METHOD

A Medline search using metabolic syndrome, insulin resistance and insulin sensitivity cross-referenced with schizophrenia was performed on articles published between 1990 and May 2008.

RESULTS

Recent evidence indicates that schizophrenia increases predisposition towards metabolic dysfunction independent of environmental exposure. Both fasting and non-fasting triglycerides have emerged as important indicators of cardiometabolic risk, while metformin, thiazolidinediones and GLP-1 modulators may prove promising tools for managing insulin resistance.

CONCLUSION

Because of lifestyle, disease and medication effects, schizophrenia patients have significant risk for cardiometabolic disease. Routine monitoring, preferential use of metabolically neutral antipsychotics and lifestyle education are critical to minimizing risk, with a possible role for antidiabetic medications for management of insulin resistant states that do not respond to other treatment strategies.

Transgene expression and silencing in a tick cell line: A model system for functional tick genomics

The genome project of the black legged tick, Ixodes scapularis, provides sequence data for testing gene function and regulation in this important pathogen vector. We tested Sleeping Beauty (SB), a Tc1/mariner group transposable element, and cationic lipid-based transfection reagents for delivery and genomic integration of transgenes into I. scapularis cell line ISE6. Plasmid DNA and dsRNA were effectively transfected into ISE6 cells and they were successfully transformed to express a red fluorescent protein (DsRed2) and a selectable marker, neomycin phosphotransferase (NEO). Frequency of transformation was estimated as 1 transformant per 5000-10,000 cells and cultures were incubated for 2-3 months in medium containing the neomycin analog G418 in order to isolate transformants. Genomic integration of the DsRed2 transgene was confirmed by inverse PCR and sequencing that demonstrated a TA nucleotide pair inserted between SB inverted/direct repeat sequences and tick genomic sequences, indicating that insertion of the DsRed2 gene into the tick cell genome occurred through the activity of SB transposase. RNAi using dsRNA transcribed from the DsRed2 gene silenced expression of red fluorescent protein in transformed ISE6 cells. SB transposition in cell line ISE6 provides an effective means to explore the functional genomics of I. scapularis.

Relationships between biochemical markers of bone and cartilage degradation with radiological progression in patients with knee osteoarthritis receiving risedronate: the Knee Osteoarthritis Structural Arthritis randomized clinical trial

OBJECTIVE

To investigate whether early changes in biochemical markers of bone (NTX-I) and cartilage (CTX-II [C-terminal crosslinking telopeptide of type II collagen]) degradation are associated with radiological progression in patients with knee osteoarthritis (OA) receiving risedronate.

DESIGN

Two thousand four hundred and eighty three patients with medial compartment knee OA were randomized in two 24-month studies in North America (NA) and European Union (EU). Studies evaluated risedronate 5 mg/day, 35 mg/week (EU), 50 mg/week (NA), and 15 mg/day (NA and EU), compared to placebo in reducing signs and symptoms and in slowing radiographic progression. One thousand eight hundred and eighty five patients from the pooled EU and NA studies with available NTX-I/CTX-II at both baseline and 6 months and radiographs at baseline and at 24 months were analyzed.

RESULTS

Risedronate produced a dose-dependent reduction of NTX-I and CTX-II observed at 6 months which continued up to 24 months. Patients who had CTX-II levels returned to low levels (<150 ng/mmol creatinine) at 6 months had a lower risk of radiographic progression at 24 months than patients whose CTX-II levels were increased both at baseline and 6 months [odds-ratio (95% confidence interval): 0.57 (0.39-0.85) after adjustment for demographics and joint space width]. The lowest risk of progression was observed in patients who had low CTX-II levels both at baseline and at 6 months [odds-ratio 0.36 (0.21-0.63)]. No significant association between NTX-I levels and radiological progression was observed.

CONCLUSION

CTX-II decreased with risedronate in patients with knee OA and levels reached after 6 months were associated with radiological progression at 24 months. Monitoring a marker of cartilage degradation 6 months after initiating treatment may be instructive in identifying patients with low progression.

Accuracy of body image perception and preferred weight loss strategies in schizophrenia: a controlled pilot study

OBJECTIVE

Obesity in severely mentally ill (SMI) populations is an increasing problem, but there is no controlled data regarding the relationship between SMI and weight perception.

METHOD

Fifty patients with schizophrenia and 50 demographically matched control participants were recruited. Weight, height, and body image accuracy were assessed for all participants, and assessments of mood, psychotic symptom severity and anxiety, and preferred modes of weight loss were assessed for the schizophrenia sample.

RESULTS

Patients with schizophrenia were significantly more likely to be obese than controls (46% vs. 18%, P < 0.005), and most patients expressed an interest in losing weight. Obese participants with schizophrenia underestimated their body size (11.0%) more than controls (4.9%) (P < 0.05).

CONCLUSION

Patients with schizophrenia are more likely to underestimate their body size, independent of the effects of obesity. However, they also express concern about weight issues and willingness to participate in psychoeducational groups targeted at weight loss.

Correlation between bone lesion changes and cartilage volume loss in patients with osteoarthritis of the knee as assessed by quantitative magnetic resonance imaging over a 24-month period

OBJECTIVE

To evaluate in patients with knee osteoarthritis (OA) the size changes in bone oedema and cysts over 24 months, and to contrast these changes with cartilage volume loss using quantitative magnetic resonance imaging.

METHODS

107 patients with knee OA, selected from a large trial evaluating the effect of a bisphosphonate, were analysed by magnetic resonance imaging at baseline and 24 months. Assessments of subchondral bone oedema and cysts, and cartilage volume were done.

RESULTS

At baseline, 86 patients showed the presence of at least one type of bone lesion: 71 oedema, 61 cysts and 51 both. At 24 months, although not statistically significant, the oedema total size change increased by 2.09 (SD 15.03) mm, and the cyst by 1.09 (8.13) mm; mean size change for the oedema was +0.38 (2.18) mm and -0.10 (4.36) mm for the cyst. When analysed according to subregions, an increase was found for the cyst size in the trochlea (+0.67 (2.74) mm, p = 0.02) and in the lateral tibial plateau (+0.15 (0.83) mm, p = 0.09), and for the oedema size in the medial tibial plateau (+1.73 (8.11) mm, p = 0.05). At 24 months, significant correlations were seen between the loss of cartilage volume and oedema size change in the medial condyle (-0.40, p = 0.0001) and the medial tibial plateau (-0.23, p = 0.03), and the changes in cyst size in the medial condyle (-0.29, p = 0.01). A multivariate analysis showed that the oedema size change was strongly and independently associated with medial cartilage volume loss (-0.31, p = 0.0004).

CONCLUSION

These data demonstrate that bone lesions are prevalent in knee OA. The correlation of the oedema and cyst size increase in the medial compartment over time with a greater loss of cartilage volume in this area underlines the importance of subchondral bone lesions in OA pathophysiology.

UGT1A1 promoter polymorphism increases risk of nilotinib-induced hyperbilirubinemia

Nilotinib is a novel BCR-ABL inhibitor with significantly improved potency and selectivity over imatinib. In Phase I and Phase II clinical studies of nilotinib in patients with a variety of leukemias, infrequent instances of reversible, benign elevation of bilirubin were observed. Uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) glucuronidates bilirubin in humans, and a polymorphism in the promoter of the gene that encodes it has been associated with hyperbilirubinemia during treatment with a number of drugs. Pharmacogenetic analysis of that TA-repeat polymorphism found an association between the (TA)7/(TA)7 genotype and risk of hyperbilirubinemia in Phase I patients with imatinib-resistant/intolerant chronic myeloid leukemia (CML) or relapsed/refractory Ph+ acute lymphoblastic leukemia (ALL); this result was replicated in two separate analyses of the chronic phase (CP) and accelerated phase (AP) CML arms of a Phase II study. As nilotinib is not known to be glucuronidated by UGT1A1, the combined impact of inhibition of UGT1A1 activity by nilotinib and genetic polymorphism is the most likely cause of the increased rate of hyperbilirubinemia.

Morphological and molecular characterization of a Hirsutella species infecting the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), in Florida

The Asian citrus psyllid, Diaphorina citri Kuwayama, is an invasive pest that vectors citrus greening disease, which recently was detected in Florida. Mycosed adult D. citri were collected at four sites in central Florida between September 2005 and February 2006. Observation of the cadavers using scanning electron microscopy revealed that the pathogen had branched synnemata supporting monophiladic conidiogenous cells. A high-fidelity polymerase chain reaction (PCR) assay was used to amplify the 18S rRNA, 28S rRNA and beta-tubulin genes of the pathogen for phylogenetic analysis. The morphological and genetic data indicated that the pathogen was a novel isolate related to Hirsutella citriformis Speare. PCR assays using isolate-specific primers designed from the unique putative intron region of the beta-tubulin sequence distinguished the psyllid pathogen from five related Hirsutella species. The pathogen was maintained in vivo by exposing healthy D. citri to the synnemata borne on field-collected cadavers. Infected psyllids had an abundance of septate hyphal bodies in their hemolymph and exhibited behavioral symptoms of disease. In vitro cultures of the pathogen were slow-growing and produced synnemata similar to those found on mycosed D. citri. In laboratory bioassays, high levels of mortality were observed in D. citri that were exposed to the conidia-bearing synnemata produced in vivo and in vitro.

Comparison of fixed flexion, fluoroscopic semi-flexed and MTP radiographic methods for obtaining the minimum medial joint space width of the knee in longitudinal osteoarthritis trials

OBJECTIVE

To compare three radiographic techniques (fluoroscopic semi-flexed [Fluoro], fixed flexion [FF], and semi-flexed metatarsophalangeal joint [MTP] views) for measuring medial joint space width (JSW) of the knee in longitudinal osteoarthritis (OA) trials and to identify the percentage of patients with detectable progression.

DESIGN

Retrospective summary of the progression and variability of the change in JSW in knee OA.

MATERIAL AND METHODS

Data from the placebo arms of three separate, structure modifying, knee OA trials were compared including gender, age, baseline JSW, change from baseline in JSW, duration of observation, and number and percent of patients with joint space narrowing of various degrees. Computer evaluation of the joint space at its narrowest point in the medial compartment was used in the studies. It is important to note that the narrowest joint space at baseline may not be in the same anatomic location at subsequent evaluations. No statistical tests were performed.

RESULTS

The average observation times were 0.98, 0.68 and 0.82 years for the Fluoro, FF, and MTP studies, respectively. The amount of progression was different among the three studies. The Fluoro study showed the greatest magnitude of OA structural progression and the lowest variability. The Fluoro study was expected to show the greatest magnitude of structural progression since it was conducted for the longest duration. For all patients, the standard deviation of the change in JSW was 0.42, 0.63, and 0.53 mm for the Fluoro, FF, and MTP studies, respectively. The percent of patients with detectable progression was similar across studies.

CONCLUSION

With these data, information was not sufficient to control for duration of observation and differences in inclusion criteria for the three study populations. Therefore, no definitive conclusions can be made regarding the degree of progression of OA over specific time intervals. However, the data indicate that all three studies contain a cohort of patients that exhibit detectable progression.

Siderophore production by a marine Pseudomonas aeruginosa and its antagonistic action against phytopathogenic fungi

A marine isolate of fluorescent Pseudomonas sp. having the ability to produce the pyoverdine type of siderophores under low iron stress (up to 10 microM iron in the succinate medium) was identified as Pseudomonas aeruginosa by using BIOLOG Breathprint and siderotyping. Pyoverdine production was optimum at 0.2% (w/v) succinate, pH 6.0, in an iron-deficient medium. Studies carried out in vitro revealed that purified siderophores and Pseudomonas culture have good antifungal activity against the plant deleterious fungi, namely, Aspergillus niger, Aspergillus flavus, Aspergillus oryzae, Fusarium oxysporum, and Sclerotium rolfsii. Siderophore-based maximum inhibition was observed against A. niger. These in vitro antagonistic actions of marine Pseudomonas against phytopathogens suggest the potential of the organism to serve as a biocontrol agent.

Meniscal tear and extrusion are strongly associated with progression of symptomatic knee osteoarthritis as assessed by quantitative magnetic resonance imaging

BACKGROUND

The relation between knee meniscal structural damage and cartilage degradation is plausible but not yet clearly proven.

OBJECTIVES

To quantitate the cartilage volume changes in knee osteoarthritis using magnetic resonance imaging (MRI), and determine whether meniscal alteration predicts cartilage volume loss over time.

METHODS

32 patients meeting ACR criteria for symptomatic knee osteoarthritis were studied. MRI knee acquisitions were done every six months for two years. The cartilage volumes of different knee regions were measured. Three indices of structural change in the medial and lateral menisci were evaluated--degeneration, tear, and extrusion--using a semiquantitative scale.

RESULTS

24 patients (75%) had mild to moderate or severe meniscal damage (tear or extrusion) at baseline. A highly significant difference in global cartilage volume loss was observed between severe medial meniscal tear and absence of tear (mean (SD), -10.1 (2.1)% v -5.1 (2.4)%, p = 0.002). An even greater difference was found between the medial meniscal changes and medial compartment cartilage volume loss (-14.3 (3.0)% in the presence of severe tear v -6.3 (2.7)% in the absence of tear; p<0.0001). Similarly, a major difference was found between the presence of a medial meniscal extrusion and loss of medial compartment cartilage volume (-15.4 (4.1)% in the presence of extrusion v -4.5 (1.7)% with no extrusion; p<0.001).

CONCLUSIONS

Meniscal tear and extrusion appear to be associated with progression of symptomatic knee osteoarthritis.

Siderotyping of Antarctic fluorescent Pseudomonas strains

Five fluorescent Pseudomonas strains isolated from Antarctica have been previously recognized as producing three structurally different pyoverdines. In the present work, siderotyping procedures have been used to classify these strains, together with 1282 isolates of different origins, into siderovars. The strain biodiversity encountered within each siderovar, as well as the potential taxonomic value of the siderovars, are described and discussed. It is concluded that a majority of antarctic strains are commonly distributed worldwide. One strain, however, presenting a particular pyoverdine structure found in a unique other isolate, was apparently much more specific to cold environment.

Reliability of a quantification imaging system using magnetic resonance images to measure cartilage thickness and volume in human normal and osteoarthritic knees

OBJECTIVE

The aim of this study was to evaluate the reliability of a software tool that assesses knee cartilage volumes using magnetic resonance (MR) images. The objectives were to assess measurement reliability by: (1) determining the differences between readings of the same image made by the same reader 2 weeks apart (test-retest reliability), (2) determining the differences between the readings of the same image made by different readers (between-reader agreement), and (3) determining the differences between the cartilage volume readings obtained from two MR images of the same knee image acquired a few hours apart (patient positioning reliability).

METHODS

Forty-eight MR examinations of the knee from normal subjects, patients with different stages of symptomatic knee osteoarthritis (OA), and a subset of duplicate images were independently and blindly quantified by three readers using the imaging system. The following cartilage areas were analyzed to compute volumes: global cartilage, medial and lateral compartments, and medial and lateral femoral condyles.

RESULTS

Between-reader agreement of measurements was excellent, as shown by intra-class correlation (ICC) coefficients ranging from 0.958 to 0.997 for global cartilage (P<0.0001), 0.974 to 0.998 for the compartments (P<0.0001), and 0.943 to 0.999 for the condyles(P<0.0001). Test-retest reliability of within-reader data was also excellent, with Pearson correlation coefficients ranging from 0.978 to 0.999 (P<0.0001). Patient positioning reliability was also excellent, with Pearson correlation coefficients ranging from 0.978 to 0.999 (P<0.0001).

CONCLUSIONS

The results of this study establish the reliability of this MR imaging system. Test-retest reliability, between-reader agreement, and patient positioning reliability were all extremely high. This study represents a first step in the overall validation of an imaging system designed to follow progression of human knee OA.