ATX expression is increased in ATX conditional transgenic mice.

<p>(A) Schematic of the experimental strategy to assess formation of the retinal vasculature in ATX conditional Tg (ATX cTg) mice. (B) LysoPLD activity of ATX cTg mice plasma. LysoPLD activity was determined by liberation of choline from lysophosphatidylcholine (LPC) using 14:0-LPC as a substrate. Error bars indicate <i>s</i>.<i>d</i>. (control; n = 12, ATX cTg; n = 7). P-values were estimated by student’s <i>t</i>-test, ***P < 0.001. (C) Relative abundance of five major LPA species (16:0, 18:1, 18:2, 20:4 and 22:6-LPA) in mice plasma. Lipids in plasma were extracted with methanol and analyzed by LC-MS/MS. Error bars indicate <i>s</i>.<i>d</i>. (control; n = 12, ATX cTg; n = 7). P-values were estimated by one-way ANOVA with Bonferroni’s posttest analyses, *P < 0.05, ***P < 0.001. (D) Western blot analysis of ATX in plasma isolated from CreER and ATX cTg mice. Data in (B) and (C) were pooled from three independent experiments.</p

Overexpression of ATX delays retinal vascularization and decreases vessel branching.

<p>(A and B) Vascular defects in retina from ATX cTg mice at P6. Retina vasculature was visualized by staining the vessels with isolectin B4. Scale bar, 500 μm. (C) Magnification view of vascular plexus in retina from ATX cTg mice at P6. Scale bar, 100 μm. (D) The vascular defects were evaluated by determining the branching points quantitatively. Error bars indicate <i>s</i>.<i>d</i>. (control; n = 12, ATX cTg; n = 7). P-values were estimated by student’s <i>t</i>-test, ***P < 0.001. Data were pooled from three independent experiments.</p

Autotaxin Overexpression Causes Embryonic Lethality and Vascular Defects

<div><p>Autotaxin (ATX) is a secretory protein, which converts lysophospholipids to lysophosphatidic acid (LPA), and is essential for embryonic vascular formation. ATX is abundantly detected in various biological fluids and its level is elevated in some pathophysiological conditions. However, the roles of elevated ATX levels remain to be elucidated. In this study, we generated conditional transgenic (Tg) mice overexpressing ATX and examined the effects of excess LPA signalling. We found that ATX overexpression in the embryonic period caused severe vascular defects and was lethal around E9.5. ATX was conditionally overexpressed in the neonatal period using the Cre/loxP system, which resulted in a marked increase in the plasma LPA level. This resulted in retinal vascular defects including abnormal vascular plexus and increased vascular regression. Our findings indicate that the ATX level must be carefully regulated to ensure coordinated vascular formation</p></div

Overexpression of ATX in embryos led to lethality with severe defects.

<p>(A) Schematic diagram of the construction of ATX Tg mice. The ATX transgene was inserted at the downstream of the neo^r/pA cassette. This fragment, in which the ATX transgene is silent, was introduced into mice, and the transgene-positive offspring were then mated with CAG-Cre Tg mice. At this stage, the LNL (for loxP-neo^r/pA-loxP) cassette was excised by Cre recombinase, and the ATX transgene was activated under control of the CAG promoter in the transgene-positive embryos. (B) PCR genotyping of ATX Tg mice. After mating of LNL-ATX Tg mice with CAG-Cre Tg mice, PCR genotyping was performed. Fragments of 1.6 and 0.2 kb were amplified for LNL-ATX Tg and CAG-ATX Tg (ATX Tg) mice, respectively, whereas these products were not detected in WT littermates. (C) A picture of embryos and placentas at E11.5. (D) Defects in the yolk sac vasculature. Yolk sac from control (wild type) and ATX Tg embryos at E10.5. (E-G) Morphologies of control (wild type) (left) and ATX Tg (right) embryo proper at E9.5 and E10.5. At E10.5 (E) and E9.5 (F and G), ATX Tg embryos are easily distinguishable from control littermates (wild type). ATX Tg embryos exhibit several defects such as growth retardation (E), open and kinky neural tube (F, arrow) and abnormal allantois (G, arrow). Scale bars, 200 μm in panels D and E and 100 μm in panels F and G. (H) Quantitative RT-PCR analysis of ATX mRNA in mouse embryos at E8.5. (wild type; n = 3, CAG-Cre; n = 3, LNL-ATX Tg; n = 2, ATX Tg; n = 3,).</p

Transient ATX overexpression decreases vessel branching but does not delay retinal vascularization.

<p>(A) Schematic of the experimental strategy to assess initial defects in retinal vasculature in ATX cTg mice. (B) LysoPLD activity of ATX cTg mice plasma. Error bars indicate <i>s</i>.<i>d</i>. (control; n = 9, ATX cTg; n = 4). (C and D) Vascular defects in retina from ATX cTg mice at P6. Retina vasculature was visualized by staining the vessels with isolectin B4. Scale bar, 500 μm. (E) Magnification view of vascular plexus in retina from ATX cTg mice at P6. Scale bar, 100 μm. (F) The vascular defects were evaluated by determining the branching points quantitatively. Error bars indicate <i>s</i>.<i>d</i>. (control; n = 9, ATX cTg; n = 4). P-values were estimated by student’s <i>t</i>-test, **P < 0.01. Data in (B) and (F) were pooled from three independent experiments.</p

Genotype distribution of offspring from LNL-ATX Tg females crossed with CAG-Cre males.

<p>Genotype distribution of offspring from LNL-ATX Tg females crossed with CAG-Cre males.</p

Overexpression of ATX causes abnormal vessel morphology and vessel regression.

<p>(A and B) Magnification view of angiogenic front in retina from ATX cTg mice at P6. Control and ATX cTg retinas had similar filopodia protrusion. Scale bar, 50 μm. TM, tamoxifen. (C and D) ATX cTg retinas displayed vessel regression at vascular plexus. Control (wild type) and ATX cTg retinas labeled for CD31 (green) and collagen IV (red). Arrows highlight empty collagen IV sleeves, indicating vessel regression. Scale bar, 100 μm. (E and F) Vessel regression was evaluated quantitatively. Error bars indicate <i>s</i>.<i>d</i>. (control; n = 7, ATX cTg; n = 5). P-values were estimated by student’s <i>t</i>-test, ***P < 0.001. Data were pooled from three independent experiments.</p

Detection of Physiological Activities of G Protein-Coupled Receptor-Acting Pharmaceuticals in Wastewater

Although pharmaceuticals are generally found at very low levels in aquatic environments, concern about their potential risks to humans and aquatic species has been raised because they are designed to be biologically active. To resolve this concern, we must know whether the biological activity of pharmaceuticals can be detected in waters. Nearly half of all marketed pharmaceuticals act by binding to the G protein-coupled receptors (GPCRs). In this study, we measured the physiological activity of pharmaceuticals in wastewater. We applied the in vitro transforming growth factor-α (TGFα) shedding assay, which accurately and sensitively detect GPCR activation, to investigate the agonistic/antagonistic activities of wastewater extracts against receptors for angiotensin (AT1), dopamine (D2, D4), adrenergic family members (α1B, α2A, β1, β3), acetylcholine (M1, M3), cannabinoid (CB1), vasopressin (V1A, V2), histamine (H1, H2, H3), 5-hydroxytryptamine (5-HT1A, 5-HT2C), prostanoid (EP3), and leukotriene (BLT1). As a result, antagonistic activity against AT1, D2, α1B, β1, M1, M3, H1, and V2 receptors was detected at up to several μg/L for the first time. Agonistic activity against α2A receptor was also detected. The TGFα shedding assay is useful for measuring the physiological activity of GPCR-acting pharmaceuticals in the aquatic environment

Synthesis and Biological Evaluation of Lysophosphatidic Acid Analogues Using Conformational Restriction and Bioisosteric Replacement Strategies

Lysophosphatidic acid (LPA) is a key player in many physiological and pathophysiological processes. The biological activities of LPA are mediated through interactions withat leastsix subtypes of G-protein-coupled receptors (GPCRs) named LPA1–6. Developing a pharmacological tool molecule that activates LPA subtype receptors selectively will allow a better understanding of their specific physiological roles. Here, we designed and synthesized conformationally restricted 25 1-oleoyl LPA analogues MZN-001 to MZN-025 by incorporating its glycerol linker into dihydropyran, tetrahydropyran, and pyrrolidine rings and variating the lipophilic chain. The agonistic activities of these compounds were evaluated using the TGFα shedding assay. Overall, the synthesized analogues exhibited significantly reduced agonistic activities toward LPA1, LPA2, and LPA6, while demonstrating potent activities toward LPA3, LPA4, and LPA5 compared to the parent LPA. Specifically, MZN-010 showed more than 10 times greater potency (EC50 = 4.9 nM) than the standard 1-oleoyl LPA (EC50 = 78 nM) toward LPA5 while exhibiting significantly lower activity on LPA1, LPA2, and LPA6 and comparable potency toward LPA3 and LPA4. Based on the MZN-010 scaffold, we synthesized additional analogues with improved selectivity and potency toward LPA5. Compound MZN-021, which contains a saturated lipophilic chain, exhibited 50 times more potent activity (EC50 = 1.2 nM) than the natural LPA against LPA5 with over a 45-fold higher selectivity when compared to those of other LPA receptors. Thus, MZN-021 was found to be a potent and selective LPA5 agonist. The findings of this study could contribute to broadening the current knowledge about the stereochemical and three-dimensional arrangement of LPA pharmacophore components inside LPA receptors and paving the way toward synthesizing other subtype-selective pharmacological probes

Presentation_1_Modulations of bioactive lipids and their receptors in postmortem Alzheimer’s disease brains.PDF

BackgroundAnalyses of brain samples from Alzheimer’s disease (AD) patients may be expected to help us improve our understanding of the pathogenesis of AD. Bioactive lipids, including sphingolipids, glycerophospholipids, and eicosanoids/related mediators have been demonstrated to exert potent physiological actions and to be involved in the pathogenesis of various human diseases. In this cross-sectional study, we attempted to elucidate the associations of these bioactive lipids with the pathogenesis/pathology of AD through postmortem studies of human brains.MethodsWe measured the levels of glycerophospholipids, sphingolipids, and eicosanoids/related mediators in the brains of patients with AD (AD brains), patients with Cerad score B (Cerad-b brains), and control subjects (control brains), using a liquid chromatography-mass spectrometry method; we also measured the mRNA levels of specific receptors for these bioactive lipids in the same brain specimens.ResultsThe levels of several species of sphingomyelins and ceramides were higher in the Cerad-b and AD brains. Levels of several species of lysophosphatidic acids (LPAs), lysophosphatidylcholine, lysophosphatidylserine, lysophosphatidylethanolamine (LPE), lysophosphatidylinositol, phosphatidylcholine, phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylinositol, and phosphatidylglycerol were especially high in the Cerad-b brains, while those of lysophosphatidylglycerol (LPG) were especially high in the AD brains. Several eicosanoids, including metabolites of prostaglandin E2, oxylipins, metabolites of epoxide, and metabolites of DHA and EPA, such as resolvins, were also modulated in the AD brains. Among the lipid mediators, the levels of S1P2, S1P5, LPA1, LPA2, LPA6, P2Y10, GPR174, EP1, DP1, DP2, IP, FP, and TXA2r were lower in the AD and/or Cerad-b brains. The brain levels of ceramides, LPC, LPI, PE, and PS showed strong positive correlations with the Aβ contents, while those of LPG showed rather strong positive correlations with the presence of senile plaques and neurofibrillary tangles. A discriminant analysis revealed that LPG is especially important for AD and the LPE/PE axis is important for Cerad-b.ConclusionsComprehensive lipidomics, together with the measurement of lipid receptor expression levels provided novel evidence for the associations of bioactive lipids with AD, which is expected to facilitate future translational research and reverse translational research.</p