TBAF-Mediated [3+1] Cycloaddition of Difluorocarbene to Access gem-Difluorinated 1,2-Diazetidine Analogues as Potent Anticancer Agents

The facile synthesis of gem-difluorinated 1,2-diazetidines was achieved by metal-free [3+1] annulation between C,N-cyclic azomethine imines with difluorocarbene. A library of 30 compounds benefiting from the TBAF-mediated cyclization process could be directly assembled in moderate to good yield under mild conditions. A plausible mechanism involving the difluorocarbene pathway was proposed based on carbene trapping and control experiments. Many compounds exhibited dramatic antiproliferative activity in 4T1, A549, and HeLa tumor cell lines.

T0901317, a liver X receptor agonist, ameliorates perinatal white matter injury induced by ischemia and hypoxia in neonatal rats

Perinatal white matter injury (PWMI) can lead to permanent neurological damage in preterm infants and bring a huge economic burden to their families and society. Liver X receptors (LXRs) are transcription factors that have been confirmed to mediate the myelination process under physiological conditions and are involved in regulating neurogenesis in adult animal models of acute and chronic cerebral ischemia. However, the role of LXRs in PWMI induced by both ischemic and hypoxic stimulation in the immature brain has not been reported. Herein, we investigated the role of LXRs in a neonatal rat model of white matter loss after hypoxia-ischemia (HI) injury through intraperitoneal injection of the LXR agonist T0901317 (T09) 1 day before and 15 min postinjury. The in vivo data showed that T09 treatment significantly facilitated myelination and ameliorated neurological behavior after PWMI. Moreover, T09 enhanced the proliferation of oligodendrocyte lineage cells and reduced microgliosis and astrogliosis in the microenvironment for oligodendrocytes (OLs), maintaining a healthy microenvironment for myelinating OLs. In vitro data suggested that the expression of the myelin-related genes Plp and Cnpase was increased in OLN-93 cells after T09 intervention compared with OLN-93 cells injured by oxygen and glucose deprivation (OGD). In primary mixed astrocytes/microglia cells, T09 also reduced the expression of Il6, Cox2, Tnfa and Il10 that was induced by OGD. Mechanistically, the mRNA expression level and the protein level of ATP binding cassette subfamily A member 1 (Abca1) decreased after HI injury, and the protective effect of T09 might be related to the activation of the LXRβ-ABCA1 signaling pathway. Our study revealed the protective role of LXRs in myelination and white matter homeostasis, providing a potential therapeutic option for PWMI.

Activity and Point Mutation G699V in PcoORP1 Confer Resistance to Oxathiapiprolin in Phytophthora colocasiae Field Isolates

The oxysterol-binding protein inhibitor oxathiapiprolin is a new fungicide for controlling oomycetes diseases. Besides, laboratory mutagenesis oxathiapiprolin-resistance among phytopathogenic oomycetes in the field remains unknown. Here, the sensitivity of 97 P. colocasiae isolates to oxathiapiprolin was examined that were collected between 2011 and 2016. We obtained a baseline sensitivity with a mean EC₅₀ value of 5.2639 × 10^-4 μg mL^-1. We showed that 6/32 isolates collected in Fujian Province from 2019 to 2020 were resistant to oxathiapiprolin without a significant fitness penalty on sporulation, vegetative growth, and virulence of the field isolates. The oxathiapiprolin resistance field isolates contained the point mutation glycine to valine at 699 in PcoORP1. The point mutation G699V was verified to confer resistance of P. colocasiae to oxathiapiprolin using the CRISPR/Cas9 system. The mutation G699V decreased the binding affinity between oxathiapiprolin and PcoORP1. These results will improve our understanding of the mechanism of P. colocasiae resistance to oxathiapiprolin under field conditions.

Effect of liver X receptor agonist TO901317 on cognitive function in APP/PS1 double transgenic mice with Alzheimers disease and the underlying mechanism

OBJECTIVES

The liver X receptors (LXRs) are members of the nuclear hormone receptor superfamily, and LXR-β is an important receptor for cholesterol content in brain cells. LXR-β/retinoic X receptor (RXR-α)/ATP binding cassette transporter A1 (ABCA1) cholesterol transmembrane transport system is closely related to the occurrence and development of Alzheimer's disease (AD). LXR agonist TO901317 can affect the accumulation of β- amyloid protein in the brain tissue of APP/PS1 double transgenic AD mice. However, the molecular mechanism is not clarified in detail. This study aims to evaluate the effects of LXR agonist TO901317 on the cognitive function of AD mice fed with high cholesterol diet, and to explore its possible mechanism from the perspective of cholesterol metabolism.

METHODS

Twenty four male 6-month-old APP/PS1 double transgenic AD mice were randomly divided into 4 groups, 6 mice in each group: a control group (fed with normal diet), a cholesterol rich diet (CRD) group, a TO901317 group (fed with CRD combined with TO901317), and a GSK2033 group (fed with CRD combined with TO901317 and LXR antagonist GSK2033). The mice were fed with pellet feed made of high cholesterol feed, mixed with lard, egg yolk powder, and cod liver oil twice a day. TO901317 and GSK2033 were dissolved and diluted to a final concentration at 0.03%. The drugs were given to the mice daily through gastric tube according to their body weight. Meanwhile, the mice in the drug group were fed with high cholesterol diet . After feeding for 3 months, Morris water maze was used to observe the changes of spatial exploration and memory ability of AD mice in each group. The contents of TC, LDL, and HDL in serum of mice in each group were detected by cholesterol enzyme colorimetry, and the differences among the groups were compared. The expression of Aβ42 in the brain of AD mice was detected by ELISA. Western blotting was used to detect the protein levels of LXR-β, RXR-α, ABCA1, and Caveolin-1 in the brain of each group.

RESULTS

Morris water maze results showed that the times, distance and the duration of mice crossing the platform in the CRD group were significantly decreased compared with the control group (all P<0.05), while these three figures in TO901317 group were significantly increased compared with the CRD group (all P<0.05). Compared with the TO901317 group, there was a decrease of these figures in the GSK2033 group (all P<0.05). The serum TC and LDL levels in the CRD group were significantly higher than those in the control group, while HDL levels were significantly lower (all P<0.001). The figures of the TC and LDL contents level in the TO901317 group were lower than those in the CRD group, while HDL levels were higher (all P<0.001). Compared with TO901317 group, the contents of the TC and LDL in GSK2033 group were significantly increased, while HDL content was significantly decreased (all P<0.001). ELISA results showed that the production of Aβ42 peptides in the brain of CRD group was the highest while the content in the TO901317 group was significantly decreased (P<0.001), which was the lowest among the groups. The figure in the control group was close to the GSK2033 group. Western blotting results showed that the protein levels of LXR-β, RXR-α, and ABCA1 in the CRD group were significantly decreased compared with the control group, but the protein level of Caveolin-1 was increased (all P<0.01). After TO901317 treatment, the protein levels of LXR-β, RXR-α and ABCA1 were significantly increased, while the protein level of Caveolin-1 was decreased partially (all P<0.001). In the GSK2033 group, the effect of TO901317 on AD mice was partially reversed by GSK2033. Compared to TO901317 group, the protein levels of LXR-β, RXR-α, and ABCA1 showed a decrease trend, while the protein level of Caveolin-1 showed an increase state (all P<0.05).

CONCLUSIONS

High cholesterol diet leads to severer spatial exploration, learning and memory impairment in transgenic AD mice, while the LXR agonist TO901317 attenuates this effect. The mechanism may be that TO901317 promotes cholesterol efflux by activating LXR-β/RXR-α/ABCA1 transmembrane transport system, reduces the expression of Caveolin-1, improves the composition of lipid raft, and ultimately reduces the production of Aβ42 in the brain.

Capillary hemodynamics and contracting skeletal muscle oxygen pressures in male rats with heart failure: Impact of soluble guanylyl cyclase activator

In heart failure with reduced ejection fraction (HFrEF), nitric oxide-soluble guanylyl cyclase (sGC) pathway dysfunction impairs skeletal muscle arteriolar vasodilation and thus capillary hemodynamics, contributing to impaired oxygen uptake (V̇O2) kinetics. Targeting this pathway with sGC activators offers a new treatment approach to HFrEF. We tested the hypotheses that sGC activator administration would increase the O2 delivery (Q̇O2)-to-V̇O2 ratio in the skeletal muscle interstitial space (PO2is) of HFrEF rats during twitch contractions due, in part, to increases in red blood cell (RBC) flux (fRBC), velocity (VRBC), and capillary hematocrit (Hctcap). HFrEF was induced in male Sprague-Dawley rats via myocardial infarction. After 3 weeks, rats were treated with 0.3 mg/kg of the sGC activator BAY 60-2770 (HFrEF + BAY; n = 11) or solvent (HFrEF; n = 9) via gavage b.i.d for 5 days prior to phosphorescence quenching (PO2is, in contracting muscle) and intravital microscopy (resting) measurements in the spinotrapezius muscle. Intravital microscopy revealed higher fRBC (70 ± 9 vs 25 ± 8 RBC/s), VRBC (490 ± 43 vs 226 ± 35 μm/s), Hctcap (16 ± 1 vs 10 ± 1%) and a greater number of capillaries supporting flow (91 ± 3 vs 82 ± 3%) in HFrEF + BAY vs HFrEF (all P < 0.05). Additionally, PO2is was especially higher during 12-34s of contractions in HFrEF + BAY vs HFrEF (P < 0.05). Our findings suggest that sGC activators improved resting Q̇O2 via increased fRBC, VRBC, and Hctcap allowing for better Q̇O2-to-V̇O2 matching during the rest-contraction transient, supporting sGC activators as a potential therapeutic to target skeletal muscle vasomotor dysfunction in HFrEF.

Characterization of an aromatic trifluoromethyl ketone as a new warhead for covalently reversible kinase inhibitor design

An aromatic trifluoromethyl ketone moiety was characterized as a new warhead for covalently reversible kinase inhibitor design to target the non-catalytic cysteine residue. Potent and selective covalently reversible inhibitors of FGFR4 kinase were successfully designed and synthesized by utilizing this new warhead. The binding mode of a representative inhibitor was fully characterized by using multiple technologies including MALDI-TOF mass spectrometry, dialysis assay and X-ray crystallographic studies etc. This functional group was also successfully applied to discovery of a new JAK3 inhibitor, suggesting its potential application in designing other kinase inhibitors.

Structural Biology-Based Exploration of Subtype-Selective Agonists for Peroxisome Proliferator-Activated Receptors

Progress in understanding peroxisome proliferator-activated receptor (PPAR) subtypes as nuclear receptors that have pleiotropic effects on biological responses has enabled the exploration of new subtype-selective PPAR ligands. Such ligands are useful chemical biology/pharmacological tools to investigate the functions of PPARs and are also candidate drugs for the treatment of PPAR-mediated diseases, such as metabolic syndrome, inflammation and cancer. This review summarizes our medicinal chemistry research of more than 20 years on the design, synthesis, and pharmacological evaluation of subtype-selective PPAR agonists, which has been based on two working hypotheses, the ligand superfamily concept and the helix 12 (H12) holding induction concept. X-ray crystallographic analyses of our agonists complexed with each PPAR subtype validate our working hypotheses.

Synthesis and Biological Evaluation of CF3 Se-Substituted α-Amino Acid Derivatives

Several CF₃ Se-substituted α-amino acid derivatives, such as (R)-2-amino-3-((trifluoromethyl)selanyl)propanoates (5 a/6 a), (S)-2-amino-4-((trifluoromethyl)selanyl)butanoates (5 b/6 b), (2R,3R)-2-amino-3-((trifluoromethyl)selanyl)butanoates (5 c/6 c), (R)-2-((S)-2-amino-3-phenylpropanamido)-3-((trifluoromethyl)selanyl)propanoates (11 a/12 a), and (R)-2-(2-aminoacetamido)-3-((trifluoromethyl)selanyl)propanoates (11 b/12 b), were readily synthesized from natural amino acids and [Me₄ N][SeCF₃ ]. The primary in vitro cytotoxicity assays revealed that compounds 6 a, 11 a and 12 a were more effective cell growth inhibitors than the other tested CF₃ Se-substituted derivatives towards MCF-7, HCT116, and SK-OV-3 cells, with their IC₅₀ values being less than 10 μM for MCF-7 and HCT116 cells. This study indicated the potentials of CF₃ Se moiety as a pharmaceutically relevant group in the design and synthesis of novel biologically active molecules.

Histone Deacetylase 1 Reduces Lipogenesis by Suppressing SREBP1 Transcription in Human Sebocyte Cell Line SZ95

Proper regulation of sebum production is important for maintaining skin homeostasis in humans. However, little is known about the role of epigenetic regulation in sebocyte lipogenesis. We investigated histone acetylation changes and their role in key lipogenic gene regulation during sebocyte lipogenesis using the human sebaceous gland cell line SZ95. Sebocyte lipogenesis is associated with a significant increase in histone acetylation. Treatment with anacardic acid (AA), a p300 histone acetyltransferase inhibitor, significantly decreased the lipid droplet number and the expression of key lipogenic genes, including sterol regulatory-binding protein 1 (SREBP1), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC). In contrast, treatment with trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, increased the expression of these genes. Global HDAC enzyme activity was decreased, and HDAC1 and HDAC2 expression was downregulated during sebaceous lipogenesis. Interestingly, HDAC1 knockdown increased lipogenesis through SREBP1 induction, whereas HDAC1 overexpression decreased lipogenesis and significantly suppressed SREBP1 promoter activity. HDAC1 and SREBP1 levels were inversely correlated in human skin sebaceous glands as demonstrated in immunofluorescence images. In conclusion, HDAC1 plays a critical role in reducing SREBP1 transcription, leading to decreased sebaceous lipogenesis. Therefore, HDAC1 activation could be an effective therapeutic strategy for skin diseases related to excessive sebum production.

Assessment of Clinical Drug-Drug Interactions of Elagolix, a Gonadotropin-Releasing Hormone Receptor Antagonist

Elagolix is an oral gonadotropin-releasing hormone receptor antagonist indicated for the management of endometriosis-associated pain and in combination with estradiol/norethindrone acetate indicated for the management of heavy menstrual bleeding associated with uterine leiomyomas (fibroids) in premenopausal women. Elagolix coadministered with estradiol/norethindrone acetate is in late-stage development for the management of heavy menstrual bleeding associated with uterine fibroids. Based on the in vitro profile of elagolix metabolism and disposition, 9 drug-drug interaction (DDI) studies evaluating the victim and perpetrator characteristics of elagolix were conducted in 144 healthy volunteers. As a victim of cytochrome P450 (CYPs) and transporter-mediated DDIs, elagolix area under the curve (AUC) increased by ∼2-fold following coadministration with ketoconazole and by ∼5- and ∼2-fold with single and multiple doses of rifampin, respectively. As a perpetrator, elagolix decreased midazolam AUC (90% confidence interval) by 54% (50%-59%) and increased digoxin AUC by 32% (23%-41%). Elagolix decreased rosuvastatin AUC by 40% (29%-50%). No clinically significant changes in exposure on coadministration with sertraline or fluconazole occurred. A elagolix 150-mg once-daily regimen should be limited to 6 months with strong CYP3A inhibitors and rifampin because of the potential increase in bone mineral density loss, as described in the drug label. A 200-mg twice-daily regimen is recommended for no more than 1 month with strong CYP3A inhibitors and not recommended with rifampin. Elagolix is contraindicated with strong organic anion transporter polypeptide B1 inhibitors (eg, cyclosporine and gemfibrozil). Consider increasing the doses of midazolam and rosuvastatin when coadministered with elagolix, and individualize therapy based on patient response. Clinical monitoring is recommended for P-glycoprotein substrates with a narrow therapeutic window (eg, digoxin). Dose adjustments are not required for sertraline, fluconazole, bupropion (or any CYP2B6 substrate), or elagolix when coadministered.

Patterned Piezoelectric Scaffolds for Osteogenic Differentiation

The morphological clues of scaffolds can determine cell behavior and, therefore, the patterning of electroactive polymers can be a suitable strategy for bone tissue engineering. In this way, this work reports on the influence of poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) electroactive micropatterned scaffolds on the proliferation and differentiation of bone cells. For that, micropatterned P(VDF-TrFE) scaffolds were produced by lithography in the form of arrays of lines and hexagons and then tested for cell proliferation and differentiation of pre-osteoblast cell line. Results show that more anisotropic surface microstructures promote bone differentiation without the need of further biochemical stimulation. Thus, the combination of specific patterns with the inherent electroactivity of materials provides a promising platform for bone regeneration.

Histone H3K9 Demethylase JMJD2B Plays a Role in LXRα-Dependent Lipogenesis

Ligand-activated liver X receptor α (LXRα) upregulates the expression of hepatic lipogenic genes, which leads to triglyceride (TG) accumulation, resulting in nonalcoholic fatty liver disease (NAFLD). Thus, LXRα regulation may provide a novel therapeutic target against NAFLD. However, histone methylation-mediated epigenetic regulation involved in LXRα-dependent lipogenesis is poorly understood. In this study, we investigated the functional role of the histone demethylase Jumonji domain-containing protein 2B (JMJD2B) in LXRα-dependent lipogenesis. JMJD2B expression level was upregulated in HepG2 cells treated with LXRα agonist T0901317 or palmitate and the liver of mice administered with T0901317 or fed a high-fat diet. Knockdown of JMJD2B using siRNA abrogated T0901317-induced LXRα-dependent lipogenic gene expression and lowered intracellular TG accumulation. Conversely, overexpression of JMJD2B in HepG2 cells upregulated the expression of LXRα-dependent lipogenic genes, in line with increased intracellular TG levels. JMJD2B overexpression or T0901317 treatment induced the recruitment of JMJD2B and LXRα to LXR response elements (LXRE) in the promoter region of LXRα-target gene and reduced the enrichment of H3K9me2 and H3K9me3 in the vicinity of the LXRE. Furthermore, JMJD2B enhanced T0901317 or LXRα-induced transcriptional activities of reporters containing LXRE. A co-immunoprecipitation assay revealed that JMJD2B interacted with activated LXRα. Moreover, overexpression of JMJD2B in mice resulted in upregulation of hepatic LXRα-dependent lipogenic genes, consistent with development of hepatic steatosis. Taken together, these results indicate that JMJD2B plays a role in LXRα-mediated lipogenesis via removing the repressive histone marks, H3K9me2 and H3K9me3, at LXRE, which might contribute to hepatic steatosis.

VD3 and LXR agonist (T0901317) combination demonstrated greater potency in inhibiting cholesterol accumulation and inducing apoptosis via ABCA1-CHOP-BCL-2 cascade in MCF-7 breast cancer cells

Obesity is associated with hypercholesterolemia and is a global epidemic. Epidemiological and animal studies revealed cholesterol is an essential regulator of estrogen receptor positive (ER+) breast cancer progression while inhibition of cholesterol accumulation was found to prevent breast tumor growth. Individually, vitamin D and LXR agonist T0901317 showed anticancer properties. The present study investigated the effects of vitamin D₃ (VD₃, calcitriol), LXR agonist (T0901317) and a combination of VD₃ + T0901317 on cholesterol metabolism and cancer progression in ER+ breast cancer (MCF-7) cells. VD₃ or T0901317 alone reduced cholesterol accumulation significantly in MCF-7 cells concomitant with an induction of ABCA1 protein and gene expression compared to the control treatment. Most importantly, VD₃ + T0901317 combination showed higher effects in reducing cholesterol levels and increasing ABCA1 protein and gene expression compared to individual treatments. Importantly, VD₃ + T0901317 combination showed higher effects in increasing apoptosis as measured by annexin apoptosis assay, cell viability and was associated with induction of CHOP protein and gene expression. Additionally, the VD₃ + T0901317 exerted higher effects in reducing antiapoptotic BCL-2 while increased pro-apoptotic BAX gene expression compared to the individual treatments. The present results suggest that VD₃ and T0901317 combination may have an important therapeutic application to prevent obesity and hyperlipidemia mediated ER+ breast cancer progression.

Discovery of a Lead Brain-Penetrating Gonadotropin-Releasing Hormone Receptor Antagonist with Saturable Binding in Brain

We report the synthesis, radiosynthesis and biological characterisation of two gonadotropin-releasing hormone receptor (GnRH-R) antagonists with nanomolar binding affinity. A small library of GnRH-R antagonists was synthesised in 20-67 % overall yield with the aim of identifying a high-affinity antagonist capable of crossing the blood-brain barrier. Binding affinity to rat GnRH-R was determined by autoradiography in competitive-binding studies against [125 I]buserelin, and inhibition constants were calculated by using the Cheng-Prusoff equation. The radioligands were obtained in 46-79 % radiochemical yield and >95 % purity and with a molar activity of 19-38 MBq/nmol by direct nucleophilic radiofluorination. Positron emission tomography imaging in rat under baseline conditions in comparison to pretreatment with a receptor-saturating dose of GnRH antagonist revealed saturable uptake (0.1 %ID/mL) into the brain.

A new strategy for durable control of late blight in potato by a single soil application of an oxathiapiprolin mixture in early season

Root treatment with oxathiapiprolin, benthiavalicarb or their mixture Zorvec-Endavia [ZE (3+7, w/w)] was shown to provide prolonged systemic protection against foliar oomycete pathogens attacking cucumber, tomato and basil. Here we report that these fungicides can effectively protect potato plants against late blight when applied to the soil in which such potato plants are grown. In two field experiments, performed in 2019 and 2020, potato plants grown in 64 L containers were treated with a soil drench of oxathiapiprolin, benthiavalicarb or ZE at 12.5, 25 or 50 mg ai/five plants in a container. Artificial inoculations with Phytophthora infestans revealed that such treated plants were protected against late blight in a dose-dependent manner all along the season. Interestingly, oxathiapiprolin persisted in the treated soil for at least 139 days, providing systemic protection against late blight to the following potato crops grown in that treated soils. Potato plants grown in loess soil in the field were either sprayed or drenched with ZE. Plants treated via the soil were significantly better protected against late blight compared to the plants treated by a spray. The data demonstrate a new strategy for season-long protection of potato against late blight by a single soil application of ZE. The systemic nature of oxathiapiprolin and benthiavalicarb composing ZE assures the translocation to the foliage of two fungicides with different modes of action. This shall minimize the risk of developing resistance against either fungicide in the treated crops.

Theoretical study of fluorinated bioisosteres of organochlorine compounds as effective and eco-friendly pesticides

Chlordane is a worldwide banned organochlorine insecticide because of its hazard to animal and human health. It is also a persistent organic pollutant, which can affect either the soil or the aquatic life. The same applies to other chlorinated cyclodiene insecticides, such as dieldrin and aldrin. In turn, organofluorine compounds have a widespread use in agriculture. Therefore, density functional calculations and docking studies showed that the bioisosteric replacement of chlorines in the above-mentioned compounds by fluorines improves some physicochemical parameters used to estimate the toxicity and environmental risk of these compounds, as well as the ligand-enzyme (GABA_A receptor-chloride channel complex) interactions related to their insecticidal activity. This work is an effort to provide an improved new class of organofluorine pesticides.

Clinical Pharmacology of Elagolix: An Oral Gonadotropin-Releasing Hormone Receptor Antagonist for Endometriosis

The clinical pharmacology of elagolix was extensively evaluated in clinical studies in healthy subjects and in women with endometriosis. Elagolix pharmacokinetics (PK) show significant population variability, however they are minimally affected by patients' baseline characteristics and demographics, except for clinically relevant extrinsic and intrinsic factors such as coadministrated strong organic anion transporting polypeptide (OATP) 1B1 inhibitors and severe hepatic impairment, which are contraindications for the use of elagolix. These studies enabled a comprehensive understanding of elagolix mechanism of action and the downstream pharmacodynamic (PD) effects on gonadotropin and ovarian hormones, as well as full characterization of the PK/PD (PKPD) relationships of elagolix at various dosages, including the approved 150 mg once daily and 200 mg twice daily dosing regimens for the management of moderate to severe pain associated with endometriosis. Several model-based analyses have contributed to understanding of the benefit-risk profile of elagolix in patients with endometriosis, through characterization of the exposure relationship with responder rates, with changes in bone mineral density over time, as well as the interaction with coadministered drugs. Collectively, these studies and analyses served as supportive evidence for the effectiveness of the approved dosages and provided general dosing instructions of the first approved oral gonadotropin-releasing hormone receptor antagonist.

Targeting the NADPH Oxidase-4 and Liver X Receptor Pathway Preserves Schwann Cell Integrity in Diabetic Mice

Diabetes triggers peripheral nerve alterations at a structural and functional level, collectively referred to as diabetic peripheral neuropathy (DPN). This work highlights the role of the liver X receptor (LXR) signaling pathway and the cross talk with the reactive oxygen species (ROS)-producing enzyme NADPH oxidase-4 (Nox4) in the pathogenesis of DPN. Using type 1 diabetic (T1DM) mouse models together with cultured Schwann cells (SCs) and skin biopsies from patients with type 2 diabetes (T2DM), we revealed the implication of LXR and Nox4 in the pathophysiology of DPN. T1DM animals exhibit neurophysiological defects and sensorimotor abnormalities paralleled by defective peripheral myelin gene expression. These alterations were concomitant with a significant reduction in LXR expression and increase in Nox4 expression and activity in SCs and peripheral nerves, which were further verified in skin biopsies of patients with T2DM. Moreover, targeted activation of LXR or specific inhibition of Nox4 in vivo and in vitro to attenuate diabetes-induced ROS production in SCs and peripheral nerves reverses functional alteration of the peripheral nerves and restores the homeostatic profiles of MPZ and PMP22. Taken together, our findings are the first to identify novel, key mediators in the pathogenesis of DPN and suggest that targeting LXR/Nox4 axis is a promising therapeutic approach.

Elagolix Suppresses Ovulation in a Dose-Dependent Manner: Results From a 3-Month, Randomized Study in Ovulatory Women

CONTEXT

Elagolix is an oral gonadotropin-releasing hormone (GnRH) antagonist recently approved for the treatment of endometriosis-associated pain and being developed for heavy menstrual bleeding associated with uterine fibroids.

OBJECTIVE

The objective was to evaluate the effects of elagolix on ovulation and ovarian sex hormones.

DESIGN AND SETTING

This was a randomized, open-label, multicenter study.

PARTICIPANTS

Participants were healthy ovulatory women aged 18 to 40 years.

INTERVENTIONS

Elagolix was administered orally for 3 continuous 28-day dosing intervals at 100 to 200 mg once daily (QD), 100 to 300 mg twice daily (BID), and 300 mg BID plus estradiol/norethindrone acetate (E2/NETA) 1/0.5 mg QD.

MAIN OUTCOME MEASURES

The main outcomes measures were ovulation rates measured by transvaginal ultrasound, progesterone concentrations, and hormone suppression.

RESULTS

Elagolix suppressed ovulation in a dose-dependent manner. The percentage of women who ovulated was highest at 100 mg QD (78%), intermediate at 150 and 200 mg QD and 100 mg BID (47%-57%), and lowest at 200 and 300 mg BID (32% and 27%, respectively). Addition of E2/NETA to elagolix 300 mg BID further suppressed the ovulation rate to 10%. Elagolix also suppressed luteinizing hormone and follicle stimulating hormone in a dose-dependent manner, leading to dose-dependent suppression of estradiol and progesterone. Elagolix had no effect on serum biomarker of ovarian reserve, and reduced endometrial thickness compared to the screening cycle.

CONCLUSION

Women being treated with elagolix may ovulate and should use effective methods of contraception. The rate of ovulation was lowest with elagolix 300 mg BID plus E2/NETA 1/0.5 mg QD.

Oxathiapiprolin, a Novel Chemical Inducer Activates the Plant Disease Resistance

Oxathiapiprolin was developed as a specific plant pathogenic oomycete inhibitor, previously shown to have highly curative and protective activities against the pepper Phytophthora blight disease under field and greenhouse tests. Therefore, it was hypothesized that oxathiapiprolin might potentially activate the plant disease resistance against pathogen infections. This study investigated the potential and related mechanism of oxathiapiprolin to activate the plant disease resistance using the bacterium Pseudomonas syringae pv tomato (Pst) and plant Arabidopsis interaction as the targeted system. Our results showed that oxathiapiprolin could activate the plant disease resistance against Pst DC3000, a non-target pathogen of oxathiapiprolin, in Arabidopsis, tobacco, and tomato plants. Our results also showed the enhanced callose deposition and H2O2 accumulation in the oxathiapiprolin-treated Arabidopsis under the induction of flg22 as the pathogen-associated molecular pattern (PAMP) treatment. Furthermore, increased levels of free salicylic acid (SA) and jasmonic acid (JA) were detected in the oxathiapiprolin-treated Arabidopsis plants compared to the mock-treated ones under the challenge of Pst DC3000. Besides, the gene expression results confirmed that at 24 h after the infiltration with Pst DC3000, the oxathiapiprolin-treated Arabidopsis plants had upregulated expression levels of the respiratory burst oxidase homolog D (RBOHD), JA-responsive gene (PDF1.2), and SA-responsive genes (PR1, PR2, and PR5) compared to the control. Taken together, oxathiapiprolin is identified as a novel chemical inducer which activates the plant disease resistance against Pst DC3000 by enhancing the callose deposition, H2O2 accumulation, and hormone SA and JA production.

Critical Role of SREBP-1c Large-VLDL Pathway in Environment-Induced Hypertriglyceridemia of Apo AV Deficiency

Objective- APOA5 variants are strongly associated with hypertriglyceridemia, as well as increased risks of cardiovascular disease and acute pancreatitis. Hypertriglyceridemia in apo AV dysfunction often aggravates by environmental factors such as high-carbohydrate diets or aging. To date, the molecular mechanisms by which these environmental factors induce hypertriglyceridemia are poorly defined, leaving the high-risk hypertriglyceridemia condition undertreated. Previously, we reported that LXR (liver X receptor)-SREBP (sterol regulatory element-binding protein)-1c pathway regulates large-VLDL (very low-density lipoprotein) production induced by LXR agonist. However, the pathophysiological relevance of the finding remains unknown. Approach and Results- Here, we reconstitute the environment-induced hypertriglyceridemia phenotype of human APOA5 deficiency in Apoa5^-/- mice and delineate the role of SREBP-1c in vivo by generating Apoa5^-/- ;Srebp-1c^-/- mice. The Apoa5^-/- mice, which showed moderate hypertriglyceridemia on a chow diet, developed severe hypertriglyceridemia on high-carbohydrate feeding or aging as seen in patients with human apo AV deficiency. These responses were nearly completely abolished in the Apoa5^-/- ;Srebp-1c^-/- mice. Further mechanistic studies revealed that in response to these environmental factors, SREBP-1c was activated to increase triglyceride synthesis and to permit the incorporation of triglyceride into abnormally large-VLDL particles, which require apo AV for efficient clearance. Conclusions- Severe hypertriglyceridemia develops only when genetic factors (apo AV deficiency) and environmental effects (SREBP-1c activation) coexist. We demonstrate that the regulated production of large-sized VLDL particles via SREBP-1c determines plasma triglyceride levels in apo AV deficiency. Our findings explain the long-standing enigma of the late-onset hypertriglyceridemia phenotype of apo AV deficiency and suggest a new approach to treat hypertriglyceridemia by targeting genes that mediate environmental effects.

An Underlying Mechanism of Dual Wnt Inhibition and AMPK Activation: Mitochondrial Uncouplers Masquerading as Wnt Inhibitors

The importance of upregulated Wnt signaling in colorectal cancers led to efforts to develop inhibitors that target β-catenin in this pathway. We now report that several "Wnt inhibitors" that allegedly target β-catenin actually function as mitochondrial proton uncouplers that independently activate AMPK and concomitantly inhibit Wnt signaling. As expected for a process in which mitochondrial uncoupling diminishes ATP production, a mitochondrial proton uncoupler, FCCP, and a glucose metabolic inhibitor, 2-DG, activated AMPK and inhibited Wnt signaling. Also consistent with these findings, a well-known "Wnt inhibitor", FH535, functioned as a proton uncoupler, and in support of this finding, the N-methylated analog, 2,5-dichloro-N-methyl-N-(2-methyl-4-nitrophenyl)benzenesulfonamide (FH535-M), was inactive as an uncoupler and Wnt inhibitor. Apart from suggesting an opportunity to develop dual Wnt inhibitors and AMPK activators, these findings provide a cautionary tale that claims for Wnt inhibition alone require scrutiny as possible mitochondrial proton uncouplers or inhibitors of the electron transport chain.

Rapid Entry into Biologically Relevant α,α-Difluoroalkylphosphonates Bearing Allyl Protection-Deblocking under Ru(II)/(IV)-Catalysis

A convenient synthetic route to α,α-difluoroalkylphosphonates is described. Structurally diverse aldehydes are condensed with LiF2CP(O)(OCH2CH═CH2)2. The resultant alcohols are captured as the pentafluorophenyl thionocarbonates and efficiently deoxygenated with HSnBu3, BEt3, and O2, and then smoothly deblocked with CpRu(IV)(π-allyl)quinoline-2-carboxylate (1-2 mol %) in methanol as an allyl cation scavenger. These mild deprotection conditions provide access to free α,α-difluoroalkylphosphonates in nearly quantitative yield. This methodology is used to rapidly construct new bis-α,α-difluoroalkyl phosphonate inhibitors of PTPIB (protein phosphotyrosine phosphatase-1B).

The effect of statins and the synthetic LXR agonist T0901317 on expression of ABCA1 transporter protein in human lung epithelial cell lines in vitro

BACKGROUND

The pathogenesis of chronic obstructive pulmonary disease (COPD) is associated with dyslipidemia, an established co-morbidity. Statins treat hypercholesterolemia, but more recently have been trailed in the setting of COPD for their potential anti-inflammatory benefits. The outcomes of prospective trials however have been inconsistent. Thus, we hypothesize that the variation in results may have been due to statin-induced downregulation of ATP-binding cassette transporter A1 (ABCA1), thereby reducing cholesterol export. This study aims to elucidate whether statin treatment in a cellular model of COPD leads to a decrease in ABCA1 protein expression.

METHODS

To mimic the inflammatory environment of COPD, two commonly used lung epithelial cell lines (BEAS-2B and A549) were treated with tumor necrosis factor (TNF), and co-treated with cholesterol/25-hydroxycholesterol (25-OH) to mimic dyslipidemia. ABCA1 protein was detected by Western Blotting.

RESULTS

We unexpectedly showed that statins did not affect ABCA1 expression. However, the LXR agonist T0901317 significantly increased ABCA1 expression in both cell lines, while TNF, cholesterol or 25-OH induced ABCA1 protein upregulation in BEAS-2B cells, indicating cell line differences in response. There was also evidence of synergistic impacts of combined treatments on ABCA1 upregulation in BEAS-2B cells.

CONCLUSION

Statins did not have an impact on ABCA1 expression in lung epithelial cell lines, disproving our original hypothesis. However, we showed for the first time, the effect of the inflammatory cytokine TNF, cholesterol/25-OH, statins and the LXR agonist T0901317 on expression of ABCA1 transporter protein in human lung epithelial cell lines in vitro. We hope that these in vitro studies may prove beneficial for addressing dyslipidemia in COPD in the future.

Disease Control Attributes of Oxathiapiprolin Fungicides for Management of Cucurbit Downy Mildew

Oxathiapiprolin, a novel oomycete fungicide recently registered by DuPont, was reported to have high intrinsic activity against cucurbit downy mildew (Pseudoperonospora cubensis). The goal of this study was to characterize disease control attributes of oxathiapiprolin-based fungicides critical to effective management of cucurbit downy mildew. In growth chamber and greenhouse studies, oxathiapiprolin-based fungicides were compared with mandipropamid, mefenoxam + mancozeb, fluopicolide + propamocarb, cymoxanil + mancozeb, and ametoctradin + dimethomorph products for pre- and postinfection activity, local systemic movement, and protection of new growth produced after fungicide application. In preventive application, oxathiapiprolin-based fungicides significantly (P < 0.0001) inhibited downy mildew development, with the highest level of disease observed being 0.4% compared with 86.7% observed for mandipropamid. When applied postinfection, oxathiapiprolin-based fungicides significantly (P < 0.0001) suppressed disease development, but disease control was reduced relative to that observed for preventive application. There was a significant effect of formulation on the postinfection activity of oxathiapiprolin, whereby the oil dispersion (OD) formulation was more inhibitory than the water-dispersible granule formulation (0.001 ≤ P ≤ 0.049). Disease severity on the outer half leaf portion protected from spray deposition during fungicide application was lower for oxathiapiprolin-based fungicides (1.6 to 6.6%) than observed for fluopicolide + propamocarb (10.9 to 23.7%), mefenoxam + mancozeb (40.3 to 51.4%), and the nontreated controls (83.3 to 84.9%), which indicates significant acropetal movement within the leaf. Postinfection applications of oxathiapiprolin-based formulations had the greatest effect on lesion growth and sporangia production compared with the other fungicides in the experiment. When applied preventively to rapidly growing plants in a greenhouse, oxathiapiprolin-based fungicides consistently protected new growth that was not present at the time of application, with the OD formulation reducing disease severity by >75% relative to nontreated plants. The practical implications of these observations are discussed.

Synthesis of the C3 and C1 Constitutional Isomers of Trifluorosubphthalocyanine and Their Fluorescence within MDA-MB-231 Breast Tumor Cells

Metal tetrapyrrole macrocycles such as porphyrins and chlorins are ubiquitous in nature. Synthetic analogs, including phthalocyanines, have found applications in medicine, particularly as photosensitizers for photodynamic therapy and as fluorescent imaging probes. Tripyrrolic macrocycles, called subphthalocyanines (SPcs) with a smaller boron atom at their core, have similar potential as optical agents. We have recently reported a series of mixed fluorinated SPcs with varying aromaticity, showing that electronic absorption and emission are synthetically tunable across the far visible region, and that the inclusion of 4-12 peripheral fluorine atoms results in strong fluorescence within MDA-MB-231 breast tumor cells. Further probing this system, we report herein the synthesis and characterization of boron trifluorosubphthalocyanine chloride (F3SPc). The constitutional isomers F3SPc(C3) and F3SPc(C1) are readily separable by chromatography, and their identity and purity have been confirmed by 1H NMR, 19F NMR, HR APCI-MS, and HPLC. Unsurprisingly, these structurally similar F3SPcs have identical electronic absorption (λmax = 557 nm; tetrahydrofuran (THF)) and emission (λem = 574 nm; Φf = 0.27-0.28; THF). Strong fluorescence from MDA-MB-231 breast tumor cells was observed following treatment with F3SPc(C3) and F3SPc(C1) (50 µM F3SPc, 15 min), further highlighting the importance of even a limited number of peripheral fluorine atoms for this type of application.

Evaluation of Oxathiapiprolin for the Management of Sunflower Downy Mildew

Downy mildew is a yield-limiting disease of sunflower, caused by the pathogen Plasmopara halstedii. Zoospore infection of root tissue shortly after planting results in systemic infection, causing postemergence damping off or severe stunting and head sterility. Although fungicide-applied seed treatments can be an effective management tool, the pathogen is resistant to phenylamide fungicides in many growing regions, and other available fungicides have limited efficacy. Oxathiapiprolin, the first member of the piperidinyl thiazole isoxazoline fungicides, was evaluated for efficacy on downy mildew in field trials conducted from 2011 to 2015 in North Dakota. Throughout the course of the study, the rate range was narrowed from active ingredient (a.i.) at 0.45 to 116.0 µg a.i. seed^-1 to an optimal effective rate of 9.37 to 18.75 µg a.i. seed^-1. Within that optimal range, the downy mildew incidence of sunflower planted with oxathiapiprolin-treated seed was significantly lower than the incidence in the nontreated sunflower in all 11 trials with disease pressure. Additionally, downy mildew incidence of sunflower planted with oxathiapiprolin-treated seed was significantly lower than sunflower planted with competitive commercially available fungicide-treated seed in 10 of those 11 trials. The use of oxathiapiprolin by sunflower growers is likely to reduce disease incidence and subsequent yield loss to downy mildew.

Novel synergistic fungicidal mixtures of oxathiapiprolin protect sunflower seeds from downy mildew caused by Plasmopara halstedii

Plenaris (oxathiapiprolin) applied to sunflower seedlings was highly effective in controlling downy mildew incited by the oomycete Plasmopara halstedii. In vitro assays revealed strong suppression of zoospore release and cystospore germination of P.halstedii by Plenaris. Bion (acibenzolar-S-methyl) and Apron (mefenoxam) were partially effective when used singly, but performed synergistically when mixed with Plenaris. Seed treatment (coating) with Plenaris provided dose-dependent control of the disease whereas Bion and Apron provided partial or poor control. However, seeds treated with mixtures containing reduced rates of Plenaris and full rates of Bion and/or Apron provided complete control of the disease due to the synergistic interaction between these components. Such mixtures should be used for seed treatment in the field to minimize selection pressure imposed on the pathogen.

Arabidopsis GIGANTEA negatively regulates chloroplast biogenesis and resistance to herbicide butafenacil

Arabidopsis GI negatively regulates chloroplast biogenesis and resistance to the herbicide butafenacil by enhanced activity and transcriptional levels of antioxidant enzymes Chloroplast biogenesis is blocked by retrograde signaling triggered by diverse internal and external cues, including sugar, reactive oxygen species (ROS), phytohormones, and abiotic stress. Efficient chloroplast biogenesis is essential for crop productivity due to its effect on photosynthetic efficiency, and is associated with agronomic traits such as insect/disease resistance, herbicide resistance, and abiotic stress tolerance. Here, we show that the circadian clock-controlled gene GIGANTEA (GI) regulates chloroplast biogenesis in Arabidopsis thaliana. The gi-2 mutant showed reduced sensitivity to the chloroplast biogenesis inhibitor lincomycin, maintaining high levels of photosynthetic proteins. By contrast, wild-type and GI-overexpressing plants were sensitive to lincomycin, with variegated leaves and reduced photosynthetic protein levels. GI is degraded by lincomycin, suggesting that GI is genetically linked to chloroplast biogenesis. The GI mutant alleles gi-1 and gi-2 were resistant to the herbicide butafenacil, which inhibits protoporphyrinogen IX oxidase activity and triggers ROS-mediated cell death via the accumulation of chlorophyll precursors. Butafenacil-mediated accumulation of superoxide anions and H₂O₂ was not detected in gi-1 or gi-2, as revealed by histochemical staining. The activities of the antioxidant enzymes superoxide dismutase, peroxidase, and catalase were 1.2-1.4-fold higher in both gi mutants compared to the wild type. Finally, the expression levels of antioxidant enzyme genes were 1.5-2-fold higher in the mutants than in the wild type. These results suggest that GI negatively regulates chloroplast biogenesis and resistance to the herbicide butafenacil, providing evidence for a genetic link between GI and chloroplast biogenesis, which could facilitate the development of herbicide-resistant crops.

Responsiveness of rat aorta and pulmonary artery to cGMP generators in the presence of thiol or heme oxidant

This study investigated the effects of thiol and heme oxidants on responsiveness to cGMP generators in isolated rat aorta and pulmonary artery using an organ chamber. The nitric oxide (NO) donor sodium nitroprusside (SNP)-induced relaxation was impaired by exposure to the thiol oxidant diamide in both the aorta and the pulmonary artery, whereas the soluble guanylate cyclase (sGC) stimulator BAY 41-2272- or the sGC activator BAY 60-2770-induced relaxation was not affected. The impairment by diamide of SNP-induced aortic and pulmonary arterial relaxation was completely restored by post-treatment with the thiol reductant dithiothreitol. However, regardless of the vessel type, the relaxant response to SNP or BAY 41-2272 was impaired by exposure to the heme oxidant ODQ, whereas the response to BAY 60-2770 was enhanced. The ODQ-induced effects were reversed partially by post-treatment with the heme reductant dithionite. These findings indicate that thiol oxidation attenuates only the vascular responsiveness to NO donors and that heme oxidation attenuates the responsiveness to NO donors and sGC stimulators but augments that to sGC activators. Therefore, under oxidative stress, the order of usability of the vasodilators is suggested to be: NO donors < sGC stimulators < sGC activators.

Pharmacological activation of liver X receptor during cigarette smoke exposure adversely affects alveolar macrophages and pulmonary surfactant homeostasis

Smoking alters pulmonary reverse lipid transport and leads to intracellular lipid accumulation in alveolar macrophages. We investigated whether stimulating reverse lipid transport with an agonist of the liver X receptor (LXR) would help alveolar macrophages limit lipid accumulation and dampen lung inflammation in response to cigarette smoke. Mice were exposed to cigarette smoke and treated intraperitoneally with the LXR agonist T0901317. Expression of lipid capture and lipid export genes was assessed in lung tissue and alveolar macrophages. Pulmonary inflammation was assessed in the bronchoalveolar lavage (BAL). Finally, cholesterol efflux capacity and pulmonary surfactant levels were determined. In room air-exposed mice, T0901317 increased the expression of lipid export genes in macrophages and the whole lung and increased cholesterol efflux capacity without inducing inflammation or affecting the pulmonary surfactant. However, cigarette smoke-exposed mice treated with T0901317 showed a marked increase in BAL neutrophils, IL-1α, C-C motif chemokine ligand 2, and granulocyte-colony-stimulating factor levels. T0901317 treatment in cigarette smoke-exposed mice failed to increase the ability of alveolar macrophages to export cholesterol and markedly exacerbated IL-1α release. Finally, T0901317 led to pulmonary surfactant depletion only in cigarette smoke-exposed mice. This study shows that hyperactivation of LXR and the associated lipid capture/export mechanisms only have minor pulmonary effects on the normal lung. However, in the context of cigarette smoke exposure, where the pulmonary surfactant is constantly oxidized, hyperactivation of LXR has dramatic adverse effects, once again showing the central role of lipid homeostasis in the pulmonary response to cigarette smoke exposure.

A Comparison of the Effects of Prolonged (>10 Hour) Low-flow Sevoflurane, High-flow Sevoflurane, and Low-flow Isoflurane Anaesthesia on Hepatorenal Function in Orthopaedic Patients

This study compared the effects of low-flow sevoflurane, high-flow sevoflurane and low-flow isoflurane on hepatorenal function during and after more than 10 hours of anaesthesia. Twenty-five patients scheduled for elective orthopaedic surgery were categorized into three groups; low-flow sevoflurane (fresh gas flow at 1 litre/min, n=9), high-flow sevoflurane (5 l/min, n=7), or low-flow isoflurane (1 l/min, n=9). Inspiratory compound A concentrations were measured. The groups had similar duration of anaesthesia and exposure to anaesthetic agents. The area under the curve of concentration (mean, SD) of compound A in the low-flow sevoflurane group (359.8, 106.1 ppm.h) was greater than that in the high-flow sevoflurane group (61.1, 29.3 ppm.h; P<0.01). All groups showed normal plasma creatinine and creatinine clearance, and transient postoperative increases in plasma alanine aminotrans-ferase and alpha glutathione-S-transferase, as well as urinary glucose and alpha glutathione-S-transferase, with no significant differences between groups. There were no significant relationships between the area under the curve of concentration of compound A and the biomarkers. These findings suggest that prolonged anaesthesia with low-flow sevoflurane has similar effects on hepatorenal function to prolonged anaesthesia with high-flow sevoflurane and low-flow isoflurane.

Mutations in ORP1 Conferring Oxathiapiprolin Resistance Confirmed by Genome Editing using CRISPR/Cas9 in Phytophthora capsici and P. sojae

Oxathiapiprolin is a novel fungicide that was recently registered in a number of countries to control plant-pathogenic oomycetes such as Phytophthora capsici. In our previous study, point mutations G770V and G839W in oxysterol binding protein-related protein 1 (ORP1) were detected in oxathiapiprolin-resistant P. capsici isolates (PcORP1). Here, we used the CRISPR/Cas9 system to verify the effects of these two point mutations on P. capsici phenotypes. Transformants containing heterozygous G770V and G839W mutations in PcORP1 showed high levels of oxathiapiprolin resistance. The G770V transformants showed otherwise similar phenotypes compared with the wild-type isolate BYA5, including sporangia and zoospore production, cyst germination, and pathogenicity. However, two independent transformants with heterozygous G839W mutations in PcORP1 could not produce sporangia. Three transformants with an unexpected point mutation in PcORP1 (ΔN837) showed high oxathiapiprolin resistance, and either similar or significantly reduced fitness compared with BYA5. The same deletion (ΔN837) was confirmed to confer oxathiapiprolin resistance in P. sojae by using CRISPR/Cas9. These homozygous P. sojae mutants also showed either similar or strongly reduced fitness compared with the wild-type parent isolate P6497. These results improve our understanding of oxathiapiprolin resistance in Phytophthora spp., and will be useful for the development of novel oxysterol-binding protein homolog inhibitor fungicides.

Assessment of acute toxicity tests and rhizotron experiments to characterize lethal and sublethal control of soil-based pests

BACKGROUND

Characterizing lethal and sublethal control of soil-based pests with plant protection products is particularly challenging due to the complex and dynamic interplay of the system components. Here, we present two types of studies: acute toxcity experiments (homogenous exposure of individuals in soil) and rhizotron experiments (heterogeneous exposure of individuals in soil) to investigate their ability to strengthen our understanding of mechanisms driving the effectivness of the plant protection product. Experiments were conducted using larvae of the western corn rootworm Diabrotica virgifera LeConte and three pesticide active ingredients: clothianidin (neonicotinoid), chlorpyrifos (organophosphate) and tefluthrin (pyrethroid).

RESULTS

The order of compound concentrations needed to invoke a specific effect intensity (EC₅₀ values) within the acute toxicity tests was chlorpyrifos > tefluthrin > clothianidin. This order changed for the rhizotron experiments because application type, fate and transport of the compounds in the soil profile, and sublethal effects on larvae also influence their effectiveness in controlling larval feeding on corn roots.

CONCLUSION

Beyond the pure measurement of efficacy through observing relative changes in plant injury to control plants, the tests generate mechanistic understanding for drivers of efficacy apart from acute toxicity. The experiments have the potential to enhance efficacy testing and product development, and might be useful tools for assessing resistance development in the future. © 2018 Society of Chemical Industry.

Homocysteine accelerates atherosclerosis via inhibiting LXRα-mediated ABCA1/ABCG1-dependent cholesterol efflux from macrophages

AIMS

Macrophage-derived foam-cell formation plays a crucial role in the development of atherosclerosis, and liver X receptor alpha (LXRα) is a key regulator of lipid metabolism in macrophages. Homocysteine (Hcy) is an independent risk factor of atherosclerosis; however, the regulation of lipid metabolism and role of LXRα induced by Hcy in macrophages is still unknown. The present study aimed to investigate the potential role of Hcy in disordered lipid metabolism and atherosclerotic lesions, especially the effects of Hcy on cholesterol efflux in macrophages and the possible mechanisms.

MAIN METHODS

In vitro, lipid accumulation and cholesterol efflux were evaluated in THP-1 macrophages with Hcy intervention. Real-time quantitative PCR and western blot analyses were used to assess mRNA and protein levels. In vivo, atherosclerotic lesions and lipid profiles were evaluated by methionine diet-induced hyperhomocysteinemia (HHcy) in ApoE^-/- mice. The LXRα agonist T0901317 was used to verify the role of LXRα in HHcy-accelerated atherosclerosis.

KEY FINDINGS

Hcy promoted lipid accumulation and inhibited cholesterol efflux in THP-1 macrophages. HHcy mice showed increased lesion area and lipid accumulation in plaque. Both studies in vitro and in vivo showed decreased expression of ATP binding cassette transporter A1 (ABCA1) and G1 (ABCG1). T0901317 treatment increased ABCA1 and ABCG1 levels; reversed macrophage-derived foam-cell formation in THP-1 macrophages and reduced atherosclerotic lesions in ApoE^-/- mice.

SIGNIFICANCE

Inhibition of LXRα-mediated ABCA1/ABCG1-dependent cholesterol efflux from macrophages is a novel mechanism in Hcy-accelerated atherosclerosis.

Oleanolic Acid Inhibits Liver X Receptor Alpha and Pregnane X Receptor to Attenuate Ligand-Induced Lipogenesis

Liver X receptor α (LXRα) controls important biological and pathophysiological processes such as lipid homeostasis. Inhibiting LXRα transactivation may beneficial in the treatment of nonalcoholic fatty liver disease (NAFLD), which is one of the main causes of liver diseases and hyperlipidemia. Oleanolic acid (OA) is a naturally occurring triterpenoid found in many plants. It has several beneficial effects on biological pathways; however, the mechanisms underlying its effects on LXRα are unclear. Therefore, we evaluated the effects of OA on T0901317-induced LXRα activation and explored whether OA can attenuate hepatic lipogenesis. The results showed that OA significantly decreased the promoter activities of LXR response element and sterol regulatory element binding protein-1c (SREBP-1c). It also decreased the mRNA and protein expression of LXRα target genes. These resulted in reduced hepatocellular lipid content. Our results also revealed that the overall binding pose of OA is similar to the X-ray pose of T0901317. Furthermore, OA stimulated AMP-activated protein kinase phosphorylation in hepatic cells. Additionally, it increased small heterodimer partner-interacting leucine zipper protein (SMILE) but decreased steroid receptor coactivator-1 (SRC-1) recruitment to the SREBP-1c promoter region. OA also enhanced LXRα-mediated induction of reverse cholesterol transport (RCT)-related gene, ATP-binding cassette transporter (ABC) A1, and ABCG1 expression in intestinal cells. It was found that OA increased the binding of SRC-1 but decreased SMILE recruitment to the ABCG1 gene promoter region. Furthermore, it reduced valproate- and rifampin-induced LXRα- and pregnane X receptor-mediated lipogenesis, respectively, which indicates its potential benefit in treating drug-induced hepatic steatosis. The results also show that OA is liver-specific and can be selectively repressed of lipogenesis. Moreover, it preserves and enhances LXRα-induced RCT stimulation. The results show that OA may be a promising treatment for NAFLD. Additionally, it can be used in the development of LXRα agonists to prevent atherosclerosis.

Oxathiapiprolin-based fungicides provide enhanced control of tomato late blight induced by mefenoxam-insensitive Phytophthora infestans

Oxathiapiprolin is a new fungicide with extremely high efficacy against oomycete plant pathogens. Solo components oxathiapiprolin (OXPT), chlorothalonil (CHT), azoxystrobin (AZ), mandipropamid (MPD), and mefenoxam (MFX) were compared with each other and with four oxathiapiprolin pre-packed fungicidal mixtures, OXPT+CHT 1+66.7, OXPT+AZ 1+10.3, OXPT+MPD 1+8.3, and OXPT+MFX 1+3 (weight active ingredient ratio), for control efficacy of late blight induced by MFX-insensitive Phytophthora infestans strains in tomato in growth chambers and the field. Mixtures performed better than all partner fungicides alone, except OXPT. Of the four mixtures, OXPT+MFX outperformed, with the highest preventive, curative, translaminar, and systemic efficacies. In the field, OXPT+MFX was superior to other fungicides in controlling late blight epidemics induced by MFX-insensitive isolates. Its deployment in the field will combat the dominating MFX-insensitive isolates, reduce the selection pressure imposed on P. infestans and delay the buildup of subpopulations resistant to oxathiapiprolin.

The liver X receptors and sterol regulatory element binding proteins alter progesterone secretion and are regulated by human chorionic gonadotropin in human luteinized granulosa cells

There is increased expression of liver x receptor (LXR) target genes and reduced low density lipoprotein receptor (LDLR) during spontaneous luteolysis in primates. The LXRs are nuclear receptors that increase cholesterol efflux by inducing transcription of their target genes. Transcription of LDLR is regulated by sterol regulatory element binding proteins (SREBPs). Human chorionic gonadotropin (hCG) prevents luteolysis and stimulates progesterone synthesis via protein kinase A (PKA). Thus, our primary objectives are: 1) Determine the effects of LXR activation and SREBP inhibition on progesterone secretion and cholesterol metabolism, and 2) Determine whether hCG signaling via PKA regulates transcription of LXR and SREBP target genes in human luteinized granulosa cells. Basal and hCG-stimulated progesterone secretion was significantly decreased by the combined actions of the LXR agonist T0901317 and the SREBP inhibitor fatostatin, which was associated with reduced intracellular cholesterol storage. Expression of LXR target genes in the presence of T0901317 was significantly reduced by hCG, while hCG promoted transcriptional changes that favor LDL uptake. These effects of hCG were reversed by a specific PKA inhibitor. A third objective was to resolve a dilemma concerning LXR regulation of steroidogenic acute regulatory protein (STAR) expression in primate and non-primate steroidogenic cells. T0901317 induced STAR expression and progesterone synthesis in ovine, but not human cells, revealing a key difference between species in LXR regulation of luteal function. Collectively, these data support the hypothesis that LXR-induced cholesterol efflux and reduced LDL uptake via SREBP inhibition mediates luteolysis in primates, which is prevented by hCG.

Inhibition of protein arginine methyltransferase 3 activity selectively impairs liver X receptor-driven transcription of hepatic lipogenic genes in vivo

BACKGROUND AND PURPOSE

Agonists for the liver X receptor (LXR) are considered promising therapeutic moieties in cholesterol-driven diseases by promoting cellular cholesterol efflux pathways. However, current clinical application of these agents is hampered by concomitant LXR-induced activation of a lipogenic transcriptional network, leading to hepatic steatosis. Recent studies have suggested that protein arginine methyltransferase 3 (PRMT3) may act as a selective co-activator of LXR activity. Here, we verified the hypothesis that PRMT3 inhibition selectively disrupts the ability of LXR to stimulate lipogenesis while maintaining its capacity to modulate macrophage cholesterol homeostasis.

EXPERIMENTAL APPROACH

A combination of the LXR agonist T0901317 and palm oil was administered to C57BL/6 mice to maximally stimulate LXR and PRMT3 activity. PRMT3 activity was inhibited using the allosteric inhibitor SGC707.

KEY RESULTS

Treatment with SGC707 did not negatively influence the T0901317/palm oil-induced up-regulation of the cholesterol efflux ATP-binding cassette transporter genes, ABCA1 and ABCG1, in peritoneal cells. In contrast, SGC707 treatment was associated with a significant decrease in the hepatic expression of the lipogenic gene fatty acid synthase (-64%). A similar trend was observed for stearoyl-coenzyme A desaturase and acetyl CoA carboxylase expression (-43%; -56%). This obstruction of lipogenic gene transcription coincided with a significant 2.3-fold decrease in liver triglyceride content as compared with the T0901317 and palm oil-treated control group.

CONCLUSION AND IMPLICATIONS

We showed that inhibition of PRMT3 activity by SGC707 treatment selectively impairs LXR-driven transcription of hepatic lipogenic genes, while the positive effect of LXR stimulation on macrophage cholesterol efflux pathways is maintained.

Pseudoperonospora cubensis in China: Its sensitivity to and control by oxathiapiprolin

The novel fungicide oxathiapiprolin has potential for the control of downy mildew of cucumber, which is caused by Pseudoperonospora cubensis. In this study, an in vitro bioassay with detached leaves was used to determine the baseline sensitivity to oxathiapiprolin for 77 Ps. cubensis isolates from 11 provinces in China. The baseline sensitivity curve was continuous, and the average EC₅₀ value was 2.23 × 10^-4 μg ml^-1. In field trials, the control of downy mildew of cucumber was greater with oxathiapiprolin at 20 or 30 g a.i. ha^-1 than with dimethomorph at 262.5 g a.i. ha^-1. Oxathiapiprolin was taken up by cucumber roots and transported upwards to stems and leaves. The full length of PscORP1, the gene that encodes the target protein of oxathiapiprolin in Ps. cubensis, was sequenced for the first time. Our results suggested that oxathiapiprolin will be an excellent alternative fungicide for control of cucumber downy mildew. However, as Ps. cubensis is a high-risk pathogen, resistance development to oxathiapiprolin should be monitored and managed.

Class I HDAC inhibition is a novel pathway for regulating astrocytic apoE secretion

Despite the important role of apolipoprotein E (apoE) secretion from astrocytes in brain lipid metabolism and the strong association of apoE4, one of the human apoE isoforms, with sporadic and late onset forms of Alzheimer's disease (AD) little is known about the regulation of astrocytic apoE. Utilizing annotated chemical libraries and a phenotypic screening strategy that measured apoE secretion from a human astrocytoma cell line, inhibition of pan class I histone deacetylases (HDACs) was identified as a mechanism to increase apoE secretion. Knocking down select HDAC family members alone or in combination revealed that inhibition of the class I HDAC family was responsible for enhancing apoE secretion. Knocking down LXRα and LXRβ genes revealed that the increase in astrocytic apoE in response to HDAC inhibition occurred via an LXR-independent pathway. Collectively, these data suggest that pan class I HDAC inhibition is a novel pathway for regulating astrocytic apoE secretion.

Transgenic Bt Corn, Soil Insecticide, and Insecticidal Seed Treatment Effects on Corn Rootworm (Coleoptera: Chrysomelidae) Beetle Emergence, Larval Feeding Injury, and Corn Yield in North Dakota

Northern, Diabrotica barberi Smith & Lawrence (Coleoptera: Chrysomelidae), and western, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), corn rootworms are economic pests of corn, Zea mays L. in North America. We measured the impacts of corn hybrids incorporated with Cry3Bb1, Cry34/35Ab1, and pyramided (Cry3Bb1 + Cry34/35Ab1) Bacillus thuringiensis Berliner (Bt) proteins, tefluthrin soil insecticide, and clothianidin insecticidal seed treatment on beetle emergence, larval feeding injury, and corn yield at five locations from 2013 to 2015 in eastern North Dakota. In most cases, emergence was significantly lower in Bt-protected corn than in non-Bt corn hybrids. Exceptions included Wyndmere, ND (2013), where D. barberi emergence from Cry34/35Ab1 plots was not different from that in the non-Bt hybrid, and Arthur, ND (2013), where D. v. virgifera emergence from Cry3Bb1 plots did not differ from that in the non-Bt hybrid. Bt hybrids generally produced increased grain yield compared with non-Bt corn where rootworm densities were high, and larval root-feeding injury was consistently lower in Bt-protected plots than in non-Bt corn. The lowest overall feeding injury and emergence levels occurred in plots planted with the Cry3Bb1 + Cry34/35Ab1 hybrid. Time to 50% cumulative emergence of both species was 5-7 d later in Bt-protected than in non-Bt hybrids. Tefluthrin and clothianidin were mostly inconsequential in relation to beetle emergence and larval root injury. Our findings could suggest that some North Dakota populations could be in early stages of increased tolerance to some Bt toxins; however, Bt corn hybrids currently provide effective protection against rootworm injury in eastern North Dakota.

Evidence of a reverse side-chain effect of tris(pentafluoroethyl)trifluorophosphate [FAP]-based ionic liquids against pathogenic bacteria

Increased interest in ionic liquids (ILs) is due to their designable and tunable unique physicochemical properties, which are utilized for a wide variety of chemical and biotechnological applications. ILs containing the tris(pentafluoroethyl)trifluorophosphate ([FAP]) anion have been shown to have excellent hydrolytic, electrochemical and thermal stability and have been successfully used in various applications. In the present study the influence of the cation on the toxicity of the [FAP] anion was investigated. Due to the properties of [FAP] ILs, the IL-toxicity of seven cations with [FAP] compared to [Cl] was examined by determination of minimum inhibitory (MIC) and minimum bactericidal concentrations (MBC) on six Gram-positive and six Gram-negative clinically-relevant bacteria. For the first time, to our knowledge, the results provide evidence for a decrease in toxicity with increasing alkyl side-chain length, indicating that the combination of both ions is responsible for this 'reverse side-chain effect'. These findings could portend development of new non-toxic ILs as green alternatives to conventional organic solvents.

Synthetic High-Density Lipoprotein-Mediated Targeted Delivery of Liver X Receptors Agonist Promotes Atherosclerosis Regression

Targeting at enhancing reverse cholesterol transport (RCT) is apromising strategy for treating atherosclerosis via infusion of reconstitute high density lipoprotein (HDL) as cholesterol acceptors or increase of cholesterol efflux by activation of macrophage liver X receptors (LXRs). However, systemic activation of LXRs triggers excessive lipogenesis in the liver and infusion of HDL downregulates cholesterol efflux from macrophages. Here we describe an enlightened strategy using phospholipid reconstituted apoA-I peptide (22A)-derived synthetic HDL (sHDL) to deliver LXR agonists to the atheroma and examine their effect on atherosclerosis regression in vivo. A synthetic LXR agonist, T0901317 (T1317) was encapsulated in sHDL nanoparticles (sHDL-T1317). Similar to the T1317 compound, the sHDL-T1317 nanoparticles upregulated the expression of ATP-binding cassette transporters and increased cholesterol efflux in macrophages in vitro and in vivo. The sHDL nanoparticles accumulated in the atherosclerotic plaques of ApoE-deficient mice. Moreover, a 6-week low-dose LXR agonist-sHDL treatment induced atherosclerosis regression while avoiding lipid accumulation in the liver. These findings identify LXR agonist loaded sHDL nanoparticles as a promising therapeutic approach to treat atherosclerosis by targeting RCT in a multifaceted manner: sHDL itself serving as both a drug carrier and cholesterol acceptor and the LXR agonist mediating upregulation of ABC transporters in the aorta.

Chronic kidney disease alters lipid trafficking and inflammatory responses in macrophages: effects of liver X receptor agonism

BACKGROUND

Our aim was to evaluate lipid trafficking and inflammatory response of macrophages exposed to lipoproteins from subjects with moderate to severe chronic kidney disease (CKD), and to investigate the potential benefits of activating cellular cholesterol transporters via liver X receptor (LXR) agonism.

METHODS

LDL and HDL were isolated by sequential density gradient ultracentrifugation of plasma from patients with stage 3-4 CKD and individuals without kidney disease (HDLCKD and HDLCont, respectively). Uptake of LDL, cholesterol efflux to HDL, and cellular inflammatory responses were assessed in human THP-1 cells. HDL effects on inflammatory markers (MCP-1, TNF-α, IL-1β), Toll-like receptors-2 (TLR-2) and - 4 (TLR-4), ATP-binding cassette class A transporter (ABCA1), NF-κB, extracellular signal regulated protein kinases 1/2 (ERK1/2) were assessed by RT-PCR and western blot before and after in vitro treatment with an LXR agonist.

RESULTS

There was no difference in macrophage uptake of LDL isolated from CKD versus controls. By contrast, HDCKD was significantly less effective than HDLCont in accepting cholesterol from cholesterol-enriched macrophages (median 20.8% [IQR 16.1-23.7] vs control (26.5% [IQR 19.6-28.5]; p = 0.008). LXR agonist upregulated ABCA1 expression and increased cholesterol efflux to HDL of both normal and CKD subjects, although the latter continued to show lower efflux capacity. HDLCKD increased macrophage cytokine response (TNF-α, MCP-1, IL-1β, and NF-κB) versus HDLCont. The heightened cytokine response to HDLCKD was further amplified in cells treated with LXR agonist. The LXR-augmentation of inflammation was associated with increased TLR-2 and TLR-4 and ERK1/2.

CONCLUSIONS

Moderate to severe impairment in kidney function promotes foam cell formation that reflects impairment in cholesterol acceptor function of HDLCKD. Activation of cellular cholesterol transporters by LXR agonism improves but does not normalize efflux to HDLCKD. However, LXR agonism actually increases the pro-inflammatory effects of HDLCKD through activation of TLRs and ERK1/2 pathways.

Reduced silent information regulator 1 signaling exacerbates sepsis-induced myocardial injury and mitigates the protective effect of a liver X receptor agonist

Myocardial injury and dysfunction are critical manifestations of sepsis. Previous studies have reported that liver X receptor (LXR) activation is protective during sepsis. However, whether LXR activation protects against septic heart injury and its underlying mechanisms remain elusive. This study was designed to determine the role of LXR activation in the septic heart with a focus on SIRT1 (silent information regulator 1) signaling. Male cardiac-specific SIRT1 knockout mice (SIRT1-/-) and their wild-type littermates were subjected to sepsis by cecal ligation and puncture (CLP) in the presence or absence of LXR agonist T0901317. The survival rate of mice was recorded during the 7-day period post CLP. Our results demonstrated that SIRT1-/- mice suffered from exacerbated mortality and myocardial injury in comparison with their wild-type littermates. Meanwhile, T0901317 treatment improved mice survival, accompanied by significant ameliorations of myocardial injury and dysfunction in wild-type mice but not in SIRT1-/- mice. Furthermore, the levels of myocardial inflammatory cytokines (TNF-α, IL-6, IL-1β, MCP-1, MPO and HMGB1), oxidative stress (ROS generation, MDA), endoplasmic-reticulum (ER) stress (protein levels of CHOP, GRP78, GRP94, IRE1α, and ATF6), and cardiac apoptosis following CLP were inhibited by T0901317 treatment in wild-type mice but not in SIRT1-/- mice. Mechanistically, T0901317 enhanced SIRT1 signaling and the subsequent deacetylation and activation of antioxidative FoxO1 and anti-ER stress HSF1, as well as the deacetylation and inhibition of pro-inflammatory NF-ΚB and pro-apoptotic P53, thereby alleviating sepsis-induced myocardial injury and dysfunction. Our data support the promise of LXR activation as an effective strategy for relieving heart septic injury.

HDL Cholesterol Efflux Capacity in Newly Diagnosed HIV and Effects of Antiretroviral Therapy

CONTEXT

In the general population, high-density lipoprotein (HDL) cholesterol efflux capacity (HCEC) relates inversely to incident cardiovascular events. Previous studies have suggested that HCEC is decreased in HIV and that antiretroviral therapy (ART) initiation might improve HCEC.

OBJECTIVE

To evaluate HCEC in the context of ART initiation and immune activation in HIV.

DESIGN AND OUTCOME MEASURES

Baseline HCEC from 10 ART-naive HIV-infected males and 12 prospectively matched non-HIV-infected males were analyzed. In the HIV cohort, HCEC 6 months after elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (E/C/F/TDF) therapy was evaluated. HCEC served as the primary outcome and was measured by the ability of J774 mouse macrophages to efflux cholesterol. Our ex vivo assay used two cholesterol acceptors [apolipoprotein B (apoB)-depleted sera or purified HDL] and modulation of cellular efflux pathways using a liver X receptor (LXR) agonist.

RESULTS

The median age was 34 years [interquartile range (IQR), 27 to 51], and baseline HDL was 46 mg/dL (IQR, 38 to 61). HCEC was significantly greater in the non-HIV-infected subjects than in the HIV-infected subjects at baseline. HCEC, assessed using apoB-depleted sera, significantly increased after ART (no LXR agonist, baseline: median, 8.1%; IQR, 7.0% to 11.9%; after ART: median, 12.9%; IQR, 10.4% to 21.1%; P = 0.006; LXR agonist, baseline, 1.3% ± 1.3%; after ART, 2.5% ± 1.0%; P = 0.02), although not to the levels in the non-HIV-infected subjects (no LXR agonist: median, 14.9%; IQR, 11.5% to 19.1%; LXR agonist: 5.8% ± 1.3%). HCEC, assessed using purified HDL, did not significantly increase after ART. The change in HCEC with ART related inversely to the change in the percentage of CD14-CD16+ (nonclassical) monocytes (ρ = -0.74, P = 0.04) and directly to the change in the percentage of CD14+CD16- (classical) monocytes (ρ = 0.72, P = 0.045).

CONCLUSIONS

Our data suggest improvement of HCEC with E/C/F/TDF and a relationship between the ART-induced decrease in immune activation and ART-induced improvement in HCEC.

Direct detection of neural activity in vitro using magnetic resonance electrical impedance tomography (MREIT)

We describe a sequence of experiments performed in vitro to verify the existence of a new magnetic resonance imaging contrast - Magnetic Resonance Electrical Impedance Tomography (MREIT) -sensitive to changes in active membrane conductivity. We compared standard deviations in MREIT phase data from spontaneously active Aplysia abdominal ganglia in an artificial seawater background solution (ASW) with those found after treatment with an excitotoxic solution (KCl). We found significant increases in MREIT treatment cases, compared to control ganglia subject to extra ASW. This distinction was not found in phase images from the same ganglia using no imaging current. Further, significance and effect size depended on the amplitude of MREIT imaging current used. We conclude that our observations were linked to changes in cell conductivity caused by activity. Functional MREIT may have promise as a more direct method of functional neuroimaging than existing methods that image correlates of blood flow such as BOLD fMRI.

Changes in LXR signaling influence early-pregnancy lipogenesis and protect against dysregulated fetoplacental lipid homeostasis

Human pregnancy is associated with enhanced de novo lipogenesis in the early stages followed by hyperlipidemia during advanced gestation. Liver X receptors (LXRs) are oxysterol-activated nuclear receptors that stimulate de novo lipogenesis and also promote the efflux of cholesterol from extrahepatic tissues followed by its transport back to the liver for biliary excretion. Although LXR is recognized as a master regulator of triglyceride and cholesterol homeostasis, it is unknown whether it facilitates the gestational adaptations in lipid metabolism. To address this question, biochemical profiling, protein quantification, and gene expression studies were used, and gestational metabolic changes in T0901317-treated wild-type mice and Lxrab^-/- mutants were investigated. Here, we show that altered LXR signaling contributes to the enhanced lipogenesis in early pregnancy by increasing the expression of hepatic Fas and stearoyl-CoA desaturase 1 (Scd1). Both the pharmacological activation of LXR with T0901317 and the genetic ablation of its two isoforms disrupted the increase in hepatic fatty acid biosynthesis and the development of hypertriglyceridemia during early gestation. We also demonstrate that absence of LXR enhances maternal white adipose tissue lipolysis, causing abnormal accumulation of triglycerides, cholesterol, and free fatty acids in the fetal liver. Together, these data identify LXR as an important factor in early-pregnancy lipogenesis that is also necessary to protect against abnormalities in fetoplacental lipid homeostasis.