Search

Oxylipins, oxidation products of unsaturated free fatty acids (FFAs), are involved in various cellular signaling systems. Among these oxylipins, FFA epoxides are associated with beneficial effects in metabolic and cardiovascular health. FFA epoxides are metabolized to diols, which are usually biologically less active, by soluble epoxide hydrolase (sEH). Plasma epoxide-diol ratios have been used as indirect measures of sEH activity. This study was designed to examine the effects of acute elevation of individual plasma FFAs on a variety of oxylipins, particularly epoxides, diols, and their ratios. We tested if FFA epoxide-diol ratios are altered by circulating FFA levels (i.e., substrate availability) independent of sEH activity. Wistar rats received a constant intravenous infusion of olive (70% oleic acid (OA)), safflower seed (72% linoleic acid (LA)), and fish oils (rich in ω-3 FFAs) as emulsions to selectively raise OA, LA, and ω-3 FFAs (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)), respectively. As expected, olive, safflower seed, and fish oil infusions selectively raised plasma OA (57%), LA (87%), EPA (70%), and DHA (54%), respectively (p < 0.05 for all). Raising plasma FFAs exerted substrate effects to increase hepatic and plasma epoxide and diol levels. These increases in epoxides and diols occurred to similar extents, resulting in no significant changes in epoxide-diol ratios. These data suggest that epoxide-diol ratios, often used as indices of sEH activity, are not affected by substrate availability or altered plasma FFA levels and that epoxide-diol ratios may be used to compare sEH activity between conditions of different circulating FFA levels.

Background: Secondhand smoke (SHS) is a significant risk factor for cardiovascular morbidity and mortality. About 80% of SHS-related deaths are due to cardiovascular causes. Reducing SHS exposure with smoking bans is associated with improved cardiovascular outcomes in non-smokers. Soluble epoxide hydrolase (sEH) inhibitors have been shown to attenuate tobacco exposure-induced lung inflammatory responses, making them a great candidate for combating SHS exposure-induced cardiovascular outcomes. The goals of this study were to determine 1) the time course of environmentally relevant SHS exposure effects on cardiac autonomic function and blood pressure (BP) regulation and 2) whether prophylactic administration of a soluble epoxide hydrolase inhibitor (TPPU) can protect against SHS-induced autonomic and cardiovascular dysregulation. Methods: Male C57BL/6J mice (11 wk) implanted with BP/electrocardiogram (ECG) telemetry devices were exposed to 12 wks of either filtered air (FA, n=19) or 3 mg/m3 of SHS (6 hr/d, 5 d/wk, n=18), followed by 4 weeks recovery window (SHS substituted with FA). Separate mice were randomly assigned to one of the 3 groups: FA (n=12), FA+TPPU (n=12), and SHS+TPPU (n=22). TPPU (15 mg/l) was given by drinking water during the 12 weeks of exposure period (estimated dose = 3.75 ug/g/day). BP and ECG were recorded continuously for 36 hours every month when mice were not exposed. Data were stratified by 12-hour circadian window: The dark cycle (dark 1) immediately after the 5th day of exposure and the following light and dark (dark 2) cycles. Baroreflex sensitivity (BRS) was determined with the sequence method. Standard time domain heart rate variability (HRV) parameters were obtained from normal-to-normal R-R intervals. Results: SHS-exposed mice had significantly higher physical activity levels (~ 50% higher, p R01 ES025229, T32 HL086350, T32 ES007059, R35ES030443 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Study objective: Sorafenib an antiangiogenic drug which are widely used in cancer treatment, and it inhibits vascular endothelial growth factor (VEGF) and tyrosine kinases (TK)involved in both tumor cell proliferation and angiogenesis. Unfortunately, VEGF and TK inhibitors cause severe kidney glomerular injury and proteinuria. Kidney injury that occurs with sorafenib chemotherapeutic treatment is a major clinical challenge that lacks a drug to revert or reduce this kidney glomerular cell damage. Hypothesis: Epoxyeicosatrienoic acid (EET) mimics reduce the nephrotoxic effects of sorafenib on glomerular mesangial cells. Methodology: Human renal mesangial cells (HRMCs) were cultured at 37˚C in RPMI 1640 medium containing 10% FBS, 100 U/ml penicillin, and 0.1 mg/ml streptomycin. Live cell imaging was performed to monitor real-time cell death activity in HRMCs. Apoptosis was determined using the caspase 3/7 dye and the HRMCs cells were imaged every 2 hours for 72 hours using the Incucyte system. HMRCs were tested under four conditions: 1) Sorafenib (10 μM), 2) Sorafenib (10 μM) plus 8,9-EET analogs (1 μM), 3) Sorafenib (10 μM) plus 8,9-EET analogs (3 μM), 4) Sorafenib (10 μM) plus 8,9-EET analogs (10 μM). Thirteen 8,9-EET analogs were also tested for soluble epoxide hydrolase (sEH) inhibitory activity against human sEH recombinant protein. Results: Sorafenib caused significant cell death and increased caspase 3/7 activity in HRMCs. Nine of the 8,9-EET analogs were ineffective in reducing sorafenib induced HRMC cell death and caspase 3/7 activity. Four 8,9-EET analogs in a dose-dependent manner reduced sorafenib induced cell death in HRMCs. This preliminary structure activity relationship analysis revealed an oxamide group as a bioisostere for the epoxide in the 8,9-position of the fatty acid chain, producing protective effects against sorafenib induced cell death in HRMCs. Gratifyingly, this group lacked significant sEH-inhibitory activity. The 8,9-EET analogs RM-84 and MBD-32 reduced sorafenib induced caspase 3/7 activity by 20-40% in HRMCs. Additional protective action was found with the 8,9-EET analogs MDB-52-I the MDB-52-II which dose dependently reduced sorafenib induced caspase 3/7 activity by 60-90% in HRMCs. Conclusion: Collectively, these findings demonstrate the potential for 8,9-EET analogs as a therapeutic strategy against sorafenib-induced glomerular nephrotoxicity. Arkansas Research Alliance This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

A simple and sensitive fluoroimmunoassay (FIA) based on a heavy-chain antibody (VHH) for rapid detection of fenitrothion was developed. A VHH library was constructed from an immunized alpaca, and one clone recognizing fenitrothion (namely, VHHjd8) was achieved after careful biopanning. It was biotinylated by fusing with the Avi tag and biotin ligase to obtain a fusion protein (VHHjd8-BT), showing both binding capacity to fenitrothion and the streptavidin poly-horseradish peroxidase conjugate (SA-polyHRP). Based on a competitive assay format, the absorbance spectrum of oxidized 3,3',5,5'-tetramethylbenzidine generated by SA-polyHRP overlapped the emission spectrum of carbon dots, which resulted in quenching of signals due to the inner-filter effect. The developed FIA showed an IC50 value of 1.4 ng/mL and a limit of detection of 0.03 ng/mL, which exhibited 15-fold improvement compared with conventional enzyme-linked immunosorbent assay. The recovery test of FIA was validated by standard GC-MS/MS, and the results showed good consistency, indicating that the assay is an ideal tool for rapid screening of fenitrothion in bulk food samples.

The voltage-gated sodium NaV1.7 channel plays a key role as a mediator of action potential propagation in C-fiber nociceptors and is an established molecular target for pain therapy. ProTx-II is a potent and moderately selective peptide toxin from tarantula venom that inhibits human NaV1.7 activation. Here we used available structural and experimental data to guide Rosetta design of potent and selective ProTx-II-based peptide inhibitors of human NaV1.7 channels. Functional testing of designed peptides using electrophysiology identified the PTx2-3127 and PTx2-3258 peptides with IC50s of 7 nM and 4 nM for hNaV1.7 and more than 1000-fold selectivity over human NaV1.1, NaV1.3, NaV1.4, NaV1.5, NaV1.8, and NaV1.9 channels. PTx2-3127 inhibits NaV1.7 currents in mouse and human sensory neurons and shows efficacy in rat models of chronic and thermal pain when administered intrathecally. Rationally designed peptide inhibitors of human NaV1.7 channels have transformative potential to define a new class of biologics to treat pain.

We assessed the humoral immune responses to a COVID-19 vaccine in a well-controlled rhesus macaque model in comparison to humans immunized with two mRNA vaccines over several months post-second dose. The plasma IgG levels against seven coronaviruses (including SARS-CoV-2) and antibody subtypes (IgG1-4 and IgM) against SARS-CoV-2 were evaluated using multiplex assays. The neutralization capacity of plasma antibodies against original SAR-CoV-2 isolate and nine variants was evaluated in vaccinated humans and non-human primates. Immunization of macaques and humans with SARS-CoV-2 vaccines induced a robust neutralizing antibody response. In non-SIV infected adult macaques immunized with an adenoviral vector expressing S-RBD (n = 7) or N protein (n = 3), elevated levels of IgG and neutralizing antibodies were detected 2 weeks post-second dose. Immune responses to the S-RBD vaccine in SIV-infected adult macaques (n = 2) were similar to the non-SIV-infected animals. Adult humans immunized with Pfizer (n = 35) or Moderna (n = 18) vaccines developed IgG and neutralizing antibodies at 4 weeks post-second dose. In both vaccine groups, IgG 1 was the predominant subtype, followed by IgG 3. The IgG levels, including total and IgG1,2,3 elicited by Moderna vaccine, were significantly higher than the corresponding levels elicited by the Pfizer vaccine at 4 weeks post-second dose. A significant correlation was observed between the plasma total IgG antibody levels and neutralization titers in both macaques and humans. Furthermore, broad-spectrum neutralization antibodies against several variants of SARS-CoV-2 were detected in the plasma of both macaques and humans after two vaccinations.

The voltage-gated sodium NaV1.7 channel plays a key role as a mediator of action potential propagation in C-fiber nociceptors and is an established molecular target for pain therapy. ProTx-II is a potent and moderately selective peptide toxin from tarantula venom that inhibits human NaV1.7 activation. Here we used available structural and experimental data to guide Rosetta design of potent and selective ProTx-II-based peptide inhibitors of human NaV1.7 channels. Functional testing of designed peptides using electrophysiology identified the PTx2-3127 and PTx2-3258 peptides with IC50s of 7 nM and 4 nM for hNaV1.7 and more than 1,000-fold selectivity over human NaV1.1, NaV1.3, NaV1.4, NaV1.5, NaV1.8, and NaV1.9 channels. PTx2-3127 inhibits NaV1.7 currents in mouse and human sensory neurons and shows efficacy in rat models of chronic and thermal pain when administered intrathecally. Rationally-designed peptide inhibitors of human NaV1.7 channels have transformative potential to define a new class of biologics to treat pain.

Aflatoxins are mutagenic mycotoxins which are believed to impact over a billion people every year, particularly in the developing world, and, when consumed, lead to stunting, immunosuppression, and liver cancer. With the worsening of climate change, molds and their toxic secondary metabolites will become an even greater risk to humanity. In this work we use in vitro and in silico methodologies to evaluate the potential for and propose the use of multicopper oxidases, specifically laccases, to enzymatically degrade aflatoxin B1 (AFB1), a highly mutagenic mycotoxin, to a safer byproduct. A panel of assays was performed on 45 members of the multicopper oxidase family with 20 different enzymes showing the ability to degrade AFB1 and establishing the pervasiveness of this activity in the family. In order to better understand how laccases oxidize AFB1, we utilized density functional theory to identify likely atoms within AFB1 for oxidation to occur. Once a reaction scheme had been established, we employed computational docking with Rosetta to ascertain which structural features are likely to contribute to AFB1 binding. These predictions can provide insight for future efforts to optimize enzymes for detoxifying AFB1.

HIV-sensory neuropathy (HIV-SN) is a debilitating complication in HIV patients with or without anti-retroviral treatment (ART). Common symptoms of HIV-SN include pain, decreased sensation, paresthesias, and dysesthesias in a symmetric stocking-glove distribution. While HIV-1 protein such as gp120 is implicated in HIV-SN (e.g. impaired large-diameter fiber), ART itself was recently shown to contribute to HIV-SN in HIV patients and impair thin fiber. Multiple host mechanisms may play roles during the pathogenesis of HIV-SN, including neuron-glia interactions in the spinal dorsal horn (SDH), inflammation, mitochondrial dysfunction and endoplasmic reticulum stress. Concurrent infections, such as tuberculosis, also carry a higher likelihood of HIV-SN as well as environmental or genetic predisposition. Pro-inflammatory cytokines such as IL-1, IL2 receptor-alpha, and tumor necrosis factor (TNF) along with abnormal lactate levels have been identified as potential players within the complex pathophysiology of this condition. In this paper, we review the pathophysiology of HIV neuropathy, focusing on the various treatment options available or under investigation. Although several treatment options are available e.g., the capsaicin patch and spinal cord stimulation, symptomatic control of HIV-SN are often challenging. Alternative approaches such as self-hypnosis, resistance exercise, cannabinoids, and acupuncture have all shown promising results, but need further investigation.

IntroductionAlthough the physiological role of the C-terminal hydrolase domain of the soluble epoxide hydrolase (sEH-H) is well investigated, the function of its N-terminal phosphatase activity (sEH-P) remains unknown.ObjectivesThis study aimed to assess in vivo the physiological role of sEH-P.MethodsCRISPR/Cas9 was used to generate a novel knock-in (KI) rat line lacking the sEH-P activity.ResultsThe sEH-P KI rats has a decreased metabolism of lysophosphatidic acids to monoacyglycerols. KI rats grew almost normally but with less weight and fat mass gain while insulin sensitivity was increased compared to wild-type rats. This lean phenotype was more marked in males than in female KI rats and mainly due to decreased food consumption and enhanced energy expenditure. In fact, sEH-P KI rats had an increased lipolysis allowing to supply fatty acids as fuel to potentiate brown adipose thermogenesis under resting condition and upon cold exposure. The potentiation of thermogenesis was abolished when blocking PPARγ, a nuclear receptor activated by intracellular lysophosphatidic acids, but also when inhibiting simultaneously sEH-H, showing a functional interaction between the two domains. Furthermore, sEH-P KI rats fed a high-fat diet did not gain as much weight as the wild-type rats, did not have increased fat mass and did not develop insulin resistance or hepatic steatosis. In addition, sEH-P KI rats exhibited enhanced basal cardiac mitochondrial activity associated with an enhanced left ventricular contractility and were protected against cardiac ischemia-reperfusion injury.ConclusionOur study reveals that sEH-P is a key player in energy and fat metabolism and contributes together with sEH-H to the regulation of cardiometabolic homeostasis. The development of pharmacological inhibitors of sEH-P appears of crucial importance to evaluate the interest of this promising therapeutic strategy in the management of obesity and cardiac ischemic complications.

Type 1 diabetes (T1D) is the result of autoimmune-mediated destruction of pancreatic islet β-cells by activated autoreactive inflammatory cells, effecting insulin production from β-cells. The Ca2+-independent phospholipase A2β(iPLA2β), a member of PLA2 family, hydrolyzes the sn-2 substituent from glycerophospholipid substrates to yield a free fatty acid, which can be metabolized to bioactive lipids. Our work has revealed that iPLA2βactivation shifts macrophage polarization towards an inflammatory phenotype and that inhibition of iPLA2βreduces the development of T1D. We have now identified that iPLA2βactivation induces generation of select pro-inflammatory lipids in the non-obese diabetic (NOD) mice, including prostaglandins (PGs) and DHETs that accompany T1D development. To assess the role of these lipids in T1D development, NOD mice were administered (ip) polyethylene glycol 400 (vehicle), TPPU (sEH inhibitor, 3mg/ml), or PTUPB (dual antagonist of COX2/sEH, 9mg/ml) for up to 30 weeks. Measurement of blood concentrations of TPPU and PTUPB confirmed availability of the inhibitors between dosages. As expected, over the study-period glucose tolerance was impaired in the PEG group. Whereas glucose tolerance was not improved by PTUPB, it was significantly ameliorated by TPPU. These findings suggest that sEH1 inhibition, and thus the production of DHETs, can have beneficial effects in mitigating T1D development. Because different PGs can have pro- or anti-inflammatory effects, they further suggest that inhibition of COX2 may not be as effective as it may also lead to reductions in anti-inflammatory PGs. Overall, our findings support a role for select iPLA2β-derived lipids (iDLs) in T1D development and suggest developing strategies to target iPLA2βor the generation of select iDLs to prevent onset/progression of T1D. Disclosure T. White: None. S. Ramanadham: None. B. Hammock: None. Funding University of Alabama at Birmingham, Iacocca Family Foundation; U.S. Department of Veterans Affairs (BX001792, 13F-RCS-002); National Institutes of Health (R01DK69455, R01DK110292 to S.R.), (R01HL125353), (U01HD087198), (RR031535), (R01AI139072)

Rationale and Objective: We recently showed that increasing epoxyeicosatrienoic acids (EETs) in kidney by blocking soluble epoxide hydrolase (sEH), an enzyme responsible for EETs degradation, markedly attenuated the development of renal dysfunction and progression of aorto-caval (ACF)-induced congestive heart failure (CHF) in Ren-2 transgenic hypertensive rats (TGR). Therefore, in this study we examined if additional inhibition of sEH to RAS blockade could further improve the course of ACF-induced CHF in TGR. Methods: The treatment regimens were started from one week after creation of ACF and the follow-up period was 60 weeks. RAS blockade was achieved by administration of angiotensin-converting enzyme inhibitor (ACEi, trandolapril, 3 mg/L in drinking water) and sEH was blocked using a sEH inhibitor (sEHi, c -AUCB, 3 mg/L in drinking water). The following experimental groups were investigated: 1) Sham-operated TGR; 2) Untreated ACF TGR; 3) ACF TGR + ACEi; 4) ACF TGR + ACEi + sEHi (n = 36 in each ACF group). In separate groups renal hemodynamics and excretory function were evaluated two weeks post-ACF, just before the onset the decompensated phase of CHF. Results: After 29 weeks post-ACF, no animal survived. ACEi treatment greatly improved the survival rate (87%) at the end of study. Surprisingly, combined treatment with ACEi and sEHi worsened the rate (53%, p < 0.05). After 2 weeks post-ACF, untreated TGR group showed lower mean arterial pressure (MAP) (124 ± 3 vs. 146 ± 4 mmHg, p < 0.05), renal blood flow (7.6 ± 0.3 vs. 10.5 ± 0.3 mL.min -1 .g -1 , p < 0.05) and absolute sodium excretion (0.18 ± 0.06 vs. 1.09 ± 0.19 μmol.min -1 .g -1 , p Conclusion: We found that addition of sEHi to ACEi treatment did not provide better protection against CHF progression and the survival rate, indeed, decreased significantly. Thus, increasing bioavailability of tissue EETs in individuals with pharmacologically-induced suppression of the RAS is not a promising approach to further attenuate renal dysfunction and progression of CHF.

Rationale and Objective: We showed recently that increasing kidney tissue epoxyeicosatrienoic acids (EETs) by blocking soluble epoxide hydrolase (sEH) and thereby blocking EETs degradation to inactive dihydroxyeicosatrienoic acids (DHETEs) substantially attenuated the progression of chronic kidney disease (CKD) in Ren-2 transgenic hypertensive rats (TGR) subjected to 5/6 renal mass reduction (5/6 NX). In this study we examined if in this model addition of sEH inhibition to the complex (dual) renin-angiotensin system (RAS) blockade would bring additional renoprotective effects in already established CKD. Methods: TGR aged 9 weeks underwent 5/6 NX and then were left untreated for 6 weeks to develop CKD. Then dual RAS blockade : ACE inhibition (trandolapril) + angiotensin AT 1 receptor blockade (losartan) was instituted, alone or combined with sEH inhibition (c-AUCB, 3 mg/l in drinking water). During the 60 weeks’ follow-up period albuminuria and urinary creatinine excretion was repeatedly determined. The following experimental groups were investigated: ; 1) sham-operated TGR; 2) Untreated 5/6 NX TGR; 3) 5/6 NX TGR + RAS blockade ; 4) 5/6 NX TGR + RAS + sEH blockade. Sham-operated transgene-negative normotensive Hannover-Sprague Dawley (HanSD) rats served as basic controls. In separate groups renal glomerular and tubulointerstitial injury was assessed, and effects of two weeks’ treatments on systolic blood pressure (SBP, measured by telemetry) and on kidney ANG II, ANG 1-7, EETs and DHETEs levels were determined. Results: All untreated TGR died by week 14 after 5/6 NX. RAS blockade increased the final survival rate to 23%, normalized SBP (116 ± 3 vs. 198 ± 3 mmHg, p Conclusion: Addition of sEH blockade to the RAS blockade brings additional renoprotective effects on the CKD progression in 5/6 NX TGR, even when applied in the advanced phase of the disease.

Soluble epoxide hydrolase (sEH) converts epoxyeicosatrienoic acids (EETs), arachidonic acid metabolites produced by cytochrome 450 enzymes, into less metabolically active compounds. sEH inhibitors have been proposed to have vascular and neural protective effects in stroke models. Studies from our lab showed that bilateral carotid artery stenosis (BCAS), a physiologically relevant model of cognitive impairment, impairs endothelium dependent dilation in penetrating arterioles (PAs) from stroke prone spontaneously hypertensive rats (SHRSPs). We hypothesized that treatment of SHRSPs with BCAS with the sEH inhibitor, trifluoromethoxyphenyl-3 (1propionylpiperidin-4-yl) urea (TPPU) would alleviate cognitive dysfunction and improve endothelium dependent dilation in PAs. Data are shown as mean ± SEM, vehicle vs TPPU, and p

Introduction: Atrial fibrillation (AF) represents one of the most common arrhythmias seen clinically and is associated with a significant increase in morbidity and mortality, yet, current treatment paradigms have proven largely inadequate. Inflammation has been shown to play critical roles in the pathophysiology of AF. Soluble epoxide hydrolase (sEH) catalyzes the hydrolysis of anti-inflammatory epoxyeicosatrienoic acids to corresponding pro-inflammatory diols. We have previously shown beneficial effects of sEH inhibitors (sEHIs) in cardiac failure and in the reduction of atrial arrhythmia inducibility. The objective of this study is to elucidate the molecular mechanisms underlying the prevention of atrial arrhythmia inducibility by sEHIs. Methods: In vivo pressure-overload model was used to replicate chronic hypertension. Flow cytometry, electrophysiologic studies and optical mapping were used to determine the mechanistic roles of sEHIs on atrial fibrosis and the reversal of electrical remodeling in atrial myocytes. Results: We demonstrate positive effects of sEHI in AF prevention by reducing 1) inflammation, 2) atrial structural remodeling by suppression of atrial fibrosis and hypertrophy (Fig A-D), and 3) electrical remodeling in atrial myocytes (Fig E-G). Mechanistically, inhibition of sEH enzyme results in a more than three-fold decrease in cytokines and chemokines (n=5, p Conclusions: This study provides insights into the underlying mechanisms leading to AF by inflammation and represents a paradigm shift from conventional antiarrhythmic drugs, which block downstream molecules to a novel upstream therapeutic target by counteracting the inflammatory processes in AF.

Mediators of anti-hypertensive actions of docosahexaenoic acid (DHA) are largely unknown. The omega-3 epoxide of DHA, 19, 20-EDP (epoxydocosapentaenoic acid) is metabolized by soluble epoxide hydrolase (sEH), which also metabolizes the anti-inflammatory and anti-hypertensive arachidonic acid (ARA) epoxides, EETs (epoxyeicosatrienoic acids). Based in part on plasma levels of EDPs following a DHA-rich diet, we hypothesized that 19, 20-EDP contributes to the anti-hypertensive actions of DHA in angiotensin-II dependent hypertension. Treatment individually with 19, 20-EDP, and a potent sEH inhibitor (sEHI) TPPU (1-trifluoromethoxyphenyl-3-(1-propionylpiperidin-4-yl) urea) significantly lowered blood pressure (BP) as compared to angiotensin-II infused animals. The largest reduction in BP was obtained with the combination of 19, 20-EDP and TPPU, which was more efficacious than the combination of 14, 15-EET and TPPU. Oxylipin profiling revealed that 19, 20-EDP and 14, 15-EET infusion affected mostly metabolites o...

Uncontrolled combustion due to garbage recycling is a widespread activity among slum dwellers in distressed economy countries and has been indicated as a major source of dioxin contamination. However, because of the high cost and complexity of gas chromatography/high-resolution mass spectrometry (GC-HRMS) analysis, the magnitude of the problem remains largely unknown. The present study describes a first approach toward the use of a dioxin antibody-based enzyme-linked immunosorbent assay (ELISA) as the basis for a sustainable, simple, and low-cost monitoring program to assess the toxicological impact of uncontrolled combustion in slums. A panel of 16 samples was analyzed by GC-HRMS and ELISA on split extracts. Close to 20% of the analyzed samples showed dioxin concentrations up to almost twice the guidance level for residential soil in several countries, pointing out the need for performing a large-scale monitoring program. Despite the potential for variations in dioxin congener distribution due to the mixed nature of the incinerated material, there was a good correlation between the toxic equivalents as determined by GC-HRMS and ELISA. Furthermore, an interlaboratory ELISA validation showed that the capacity to perform the dioxin ELISA was successfully transferred between laboratories. It was concluded that the ELISA method performed very well as a screening tool to prioritize samples for instrumental analysis, which allows cutting down costs significantly.

Allergic contact dermatitis (CD) is a type of inflammatory skin disease resulting from delayed-typed hypersensitivity to haptenic antigens. The antigens are presented to T cells by dendritic cells in the skin and result in activation and recruitment of other immune cells to the skin. The inflammatory response is frequently accompanied by production of metabolic mediators. Here we sought to identify mediators involved in allergic CD by using a mouse model. C57BL/6 mice were sensitized with dinitrofluorobenzene or oxazolone and challenged with the same antigen on the ear. The treated ears were swollen and exhibited accumulation of leukocytes. The affected ears were subjected to targeted quantitative metabolomic analysis by mass spectrometry to identify lipid metabolites that displayed significant changes. A cyclooxygenase product, thromboxane A2, was remarkably induced by more than 10 fold compared to vehicle control. A number of other bioactive lipid metabolites were induced by more than two fold. We found that mice treated with aspirin or sEHi showed reduced ear thickness compared to vehicle treatment. Our data suggest that the cyclooxygenase and soluble epoxide hydrolase pathways are involved in the development of allergic CD by modulating the inflammatory skin response. Inhibitors of these two pathways and antagonists of prostanoid receptors for the elevated metabolites are expected to be effective therapeutically to treat allergic CD.

http://www.pnas.org/; International audience; Juvenile hormone (JH) is a sesquiterpenoid of vital importance for insect development, yet the molecular basis of JH signaling remains obscure, mainly because a bona fide JH receptor has not been identified. Mounting evidence points to the basic helix-loop-helix (bHLH)/Per-Arnt-Sim (PAS) domain protein Methoprene-tolerant (Met) as the best JH receptor candidate. However, details of how Met transduces the hormonal signal are missing. Here, we demonstrate that Met specifically binds JH III and its biologically active mimics, methoprene and pyriproxyfen, through its C-terminal PAS domain. Substitution of individual amino acids, predicted to form a ligand-binding pocket, with residues possessing bulkier side chains reduces JH III binding likely because of steric hindrance. Although a mutation that abolishes JH III binding does not affect a Met-Met complex that forms in the absence of methoprene, it prevents both the ligand-dependent dissociation of the Met-Met dimer and the ligand-dependent interaction of Met with its partner bHLH-PAS protein Taiman. These results show that Met can sense the JH signal through direct, specific binding, thus establishing a unique class of intracellular hormone receptors.