Anoctamin 1 (ANO1)/TMEM16A is a Cl<sup>−</sup> channel activated by intracellular Ca<sup>2+</sup> mediating numerous physiological functions. However, little is known of the ANO1 activation mechanism by Ca<sup>2+</sup>. Here, we demonstrate that two helices, “reference” and “Ca<sup>2+</sup> sensor” helices in the third intracellular loop face each other with opposite charges. The two helices interact directly in a Ca<sup>2+</sup>-dependent manner. Positively and negatively charged residues in the two helices are essential for Ca<sup>2+</sup>-dependent activation because neutralization of these charges change the Ca<sup>2+</sup> sensitivity. We now predict that the Ca<sup>2+</sup> sensor helix attaches to the reference helix in the resting state, and as intracellular Ca<sup>2+</sup> rises, Ca<sup>2+</sup> acts on the sensor helix, which repels it from the reference helix. This Ca<sup>2+</sup>-dependent push-pull conformational change would be a key electromechanical movement for gating the ANO1 channel. Because chemical activation of ANO1 is viewed as an alternative means of rescuing cystic fibrosis, understanding its gating mechanism would be useful in developing novel treatments for cystic fibrosis.
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Yang An;
Vijay R. Varma;
Sudhir Varma;
Ramon Casanova;
Eric Dammer;
Olga Pletnikova;
Chee W. Chia;
Josephine M. Egan;
Luigi Ferrucci;
Juan Troncoso;
Allan Levey;
James Lah;
Nicholas Seyfried;
Cristina Legido-Quigley;
Richard O'Brien;
Madhav Thambisetty
Introduction: It is unclear whether abnormalities in brain glucose homeostasis are associated with Alzheimer's disease (AD) pathogenesis. Methods: Within the autopsy cohort of the Baltimore Longitudinal Study of Aging, we measured brain glucose concentration and assessed the ratios of the glycolytic amino acids, serine, glycine, and alanine to glucose. We also quantified protein levels of the neuronal (GLUT3) and astrocytic (GLUT1) glucose transporters. Finally, we assessed the relationships between plasma glucose measured before death and brain tissue glucose. Results: Higher brain tissue glucose concentration, reduced glycolytic flux, and lower GLUT3 are related to severity of AD pathology and the expression of AD symptoms. Longitudinal increases in fasting plasma glucose levels are associated with higher brain tissue glucose concentrations. Discussion: Impaired glucose metabolism due to reduced glycolytic flux may be intrinsic to AD pathogenesis. Abnormalities in brain glucose homeostasis may begin several years before the onset of clinical symptoms.
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A Craig Lockhart;
Todd M. Bauer;
Charu Aggarwal;
Carrie B. Lee;
R Donald Harvey;
Roger B. Cohen;
Farhad Sedarati;
Tsz Keung Nip;
Hélène Faessel;
Ajeeta B. Dash;
Bruce J. Dezube;
Douglas V. Faller;
Afshin Dowlati
Purpose This phase Ib study (NCT01862328) evaluated the maximum tolerated dose (MTD), safety, and efficacy of pevonedistat in combination with standard-of-care chemotherapies in patients with solid tumors. Methods Patients received pevonedistat with docetaxel (arm 1, n = 22), carboplatin plus paclitaxel (arm 2, n = 26), or gemcitabine (arm 3, n = 10) in 21-days (arms 1 and 2) or 28-days (arm 3) cycles. A lead-in cohort (arm 2a, n = 6) determined the arm 2 carboplatin dose. Dose escalation proceeded via continual modified reassessment. Results Pevonedistat MTD was 25 mg/m 2 (arm 1) or 20 mg/m 2 (arm 2); arm 3 was discontinued due to poor tolerability. Fifteen (23%) patients experienced dose-limiting toxicities during cycle 1 (grade ≥3 liver enzyme elevations, febrile neutropenia, and thrombocytopenia), managed with dose holds or reductions. Drug-related adverse events (AEs) occurred in 95% of patients. Most common AEs included fatigue (56%) and nausea (50%). One drug-related death occurred in arm 3 (febrile neutropenia). Pevonedistat exposure increased when co-administered with carboplatin plus paclitaxel; no obvious changes were observed when co-administered with docetaxel or gemcitabine. Among 54 response-evaluable patients, two had complete responses (arm 2) and 10 had partial responses (three in arm 1, one in arm 2a, six in arm 2); overall response rates were 16% (arm 1) and 35% (arm 2). High ERCC1 expression correlated with clinical benefit in arm 2. Conclusion Pevonedistat with docetaxel or with carboplatin plus paclitaxel was tolerable without cumulative toxicity. Sustained clinical responses were observed in pretreated patients receiving pevonedistat with carboplatin and paclitaxel. ClinicalTrials.gov identifier: NCT01862328.
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Thiago A.F. Ferro;
Eliene B. Souza;
Mariela A.M. Suarez;
Joao F.S. Rodrigues;
Domingos M.S. Pereira;
Saulo J.F. Mendes;
Laoane F. Gonzaga;
Marcia C.A.M. Machado;
Maria R.Q. Bomfim;
Joao B. Calixto;
Jack Arbiser;
Valerio Monteiro-Neto;
Eunice Andre;
Elizabeth S. Fernandes
Wound healing can be delayed following colonization and infection with the common bacterium Pseudomonas aeruginosa. While multiple therapies are used for their treatment, these are ineffective, expensive, and labour-intensive. Thus, there is an enormous unmet need for the treatment of infected wounds. Cinnamaldehyde, the major component of cinnamon oil, is well known for its antimicrobial properties. Herein, we investigated the effects of sub-inhibitory concentrations of cinnamaldehyde in the virulence of P. aeruginosa. We also assessed its healing potential in P. aeruginosa-infected mouse skin wounds and the mechanisms involved in this response. Sub-inhibitory concentrations of cinnamaldehyde reduced P. aeruginosa metabolic rate and its ability to form biofilm and to cause haemolysis. Daily topical application of cinnamaldehyde on P. aeruginosa-infected skin wounds reduced tissue bacterial load and promoted faster healing. Lower interleukin-17 (IL-17), vascular endothelial growth factor (VEGF) and nitric oxide levels were detected in cinnamaldehyde-treated wound samples. Blockage of transient receptor potential ankyrin 1, the pharmacological target of cinnamaldehyde, abrogated its healing activity and partially reversed the inhibitory actions of this compound on VEGF and IL-17 generation. We suggest that topical application of sub-inhibitory concentrations of cinnamaldehyde may represent an interesting approach to improve the healing of P. aeruginosa-infected skin wounds.
It is a high priority to develop a simple and effective delivery method for a cross-protective influenza vaccine. We investigated skin immunization by microneedle (MN) patch with human influenza split vaccine and virus-like particles containing heterologous M2 extracellular (M2e) domains (M2e5x virus-like particles (VLP)) as a cross-protective influenza vaccine candidate. Co-delivery of influenza split vaccine and M2e5x VLP to the skin by MN patch was found to confer effective protection against heterosubtypic influenza virus by preventing weight loss and reducing lung viral loads. Compared to intramuscular immunization, MN-based delivery of combined split vaccine and M2e5x VLPs shaped cellular immune responses toward T helper type 1 responses increasing IgG2a isotype antibodies as well as IFN-γ producing cells in mucosal and systemic sites. This study provides evidence that potential immunological and logistic benefits of M2e5x VLP with human influenza split vaccine delivered by MN patch can be used to develop an easy-to-administer cross-protective influenza vaccine.
CYP2B proteins in rat hepatocytes undergo NO-dependent proteolytic degradation, but the mechanisms and the reasons for the specificity towards only certain P450 enzymes are yet unknown. Here, we found that down-regulation of CYP2B proteins by the NO donor NOC-18 is accelerated by pretreatment of the hepatocytes with interleukin-1β (IL-1) in the presence of a nitric oxide synthase inhibitor, suggesting that an NO-independent action of IL-1 contributes to the lability of CYP2B proteins. The immunoproteasome subunit LMP2 was significantly expressed in hepatocytes under basal conditions, and IL-1 induced LMP2 within 6–12 h of treatment. CYP2B protein degradation in response to IL-1 was attenuated by the selective LMP2 inhibitor UK-101, but not by the LMP7 inhibitor IPSI. The results show that LMP2 contributes to the NO-dependent degradation of CYP2B proteins, and suggest that induction of LMP2 may be involved in the potentiation of this degradation by IL-1.
Enigmol is a synthetic, orally active 1-deoxysphingoid base analogue that has demonstrated promising activity against prostate cancer. In these studies, the pharmacologic roles of stereochemistry and N-methylation in the structure of enigmols were examined. A novel enantioselective synthesis of all four possible 2S-diastereoisomers of enigmol (2-aminooctadecane-3,5-diols) from l-alanine is reported, which features a Liebeskind−Srogl cross-coupling reaction between l-alanine thiol ester and (E)-pentadec-1-enylboronic acid as the key step. In vitro biological evaluation of the four enigmol diastereoisomers and 2S,3S,5S-N-methylenigmol against two prostate cancer cell lines (PC-3 and LNCaP) indicates that all but one diastereomer demonstrate potent oncolytic activity. In nude mouse xenograft models of human prostate cancer, enigmol was equally effective as standard prostate cancer therapies (androgen deprivation or docetaxel), and two of the enigmol diastereomers, 2S,3S,5R-enigmol and 2S,3R,5S-enigmol, also caused statistically significant inhibition of tumor growth. A pharmacokinetic profile of enigmol and N-methylenigmol is also presented.
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Rasmus P. Clausen;
Caspar Christensen;
Kasper B. Hansen;
Jeremy R. Greenwood;
Lars Jørgensen;
Nicola Micale;
Jens Christian Madsen;
Birgitte Nielsen;
Jan Egebjerg;
Hans Bräuner-Osborne;
Stephen Traynelis;
Jesper L. Kristensen
A series of analogues based on N-hydroxypyrazole as a bioisostere for the distal carboxylate group of aspartate have been designed, synthesized, and pharmacologically characterized. Affinity studies on the major glutamate receptor subgroups show that these 4-substituted N-hydroxypyrazol-5-yl glycine (NHP5G) derivatives are selectively recognized by N-methyl-D-aspartic acid (NMDA) receptors and that the (R)-enantiomers are preferred. Moreover, several of the compounds are able to discriminate between individual subtypes among the NMDA receptors, providing new pharmacological tools. For example, 4-propyl NHP5G is an antagonist at the NR1/NR2A subtype but an agonist at the NR1/NR2D subtype. Molecular docking studies indicate that the substituent protrudes into a region that may be further exploited to improve subtype selectivity, thereby opening up a design strategy for ligands which can differentiate individual NMDA receptor subtypes.
Although critical in phagocytosis in innate immunity, reactive oxygen species (ROS) collaterally inflict damage to host phagocytes because they indiscriminate targets. Since Nrf2 increases the expression of anti-oxidant enzymes that nullifies ROS, ROS activating Nrf2 is a critical negative regulatory step for countering the deleterious effects of ROS. Here, we postulate whether, along with ROS activating Nrf2, NADPH oxidase components also participate in direct activation of Nrf2, contributing to protection from ROS. Our results show that the p47 phox of the NADPH oxidase, but not p65 phox or p40 phox , physically binds to Nrf2, activating the Nrf2 function. p47 phox binding to Nrf2/Keap1 complex suppresses the ubiquitination of Nrf2, while p47 phox becomes ubiquitinated by Keap1. p47 phox increases the nuclear translocation of Nrf2 and the expression of Nrf2-dependent genes, whereas genetic ablation of p47 phox decreases the expression of those genes. In a lipopolysaccharide-induced acute lung inflammation mouse model, selective expression of p47 phox in mouse lungs induces the expression of Nrf2-dependent genes and is sufficient to suppress neutrophilic lung inflammation. Therefore, our findings suggest that p47 phox is a novel regulator of Nrf2 function.
The transient receptor potential canonical subfamily member 5 (TRPC5), one of seven mammalian TRPC members, is a nonselective calcium-permeant cation channel. TRPC5 is of considerable interest as a drug target in the treatment of progressive kidney disease, depression, and anxiety. Here, we present the 2.8-Å resolution cryo–electron microscopy (cryo-EM) structure of the mouse TRPC5 (mTRPC5) homotetramer. Comparison of the TRPC5 structure to previously determined structures of other TRPC and TRP channels reveals differences in the extracellular pore domain and in the length of the S3 helix. The disulfide bond at the extracellular side of the pore and a preceding small loop are essential elements for its proper function. This high-resolution structure of mTRPC5, combined with electrophysiology and mutagenesis, provides insight into the lipid modulation and gating mechanisms of the TRPC family of ion channels.