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1.
Nat Rev Drug Discov ; 2024 Jun 05.
Article En | MEDLINE | ID: mdl-38839912

Despite major progress in the treatment of autoimmune diseases in the past two decades, most therapies do not cure disease and can be associated with increased risk of infection through broad suppression of the immune system. However, advances in understanding the causes of autoimmune disease and clinical data from novel therapeutic modalities such as chimeric antigen receptor T cell therapies provide evidence that it may be possible to re-establish immune homeostasis and, potentially, prolong remission or even cure autoimmune diseases. Here, we propose a 'sequential immunotherapy' framework for immune system modulation to help achieve this ambitious goal. This framework encompasses three steps: controlling inflammation; resetting the immune system through elimination of pathogenic immune memory cells; and promoting and maintaining immune homeostasis via immune regulatory agents and tissue repair. We discuss existing drugs and those in development for each of the three steps. We also highlight the importance of causal human biology in identifying and prioritizing novel immunotherapeutic strategies as well as informing their application in specific patient subsets, enabling precision medicine approaches that have the potential to transform clinical care.

3.
Open Biol ; 12(12): 220243, 2022 12.
Article En | MEDLINE | ID: mdl-36541099

The extracellular Ca2+ concentration changes locally under certain physiological and pathological conditions. Such variations affect the function of ion channels of the nervous system and consequently also neuronal signalling. We investigated here the mechanisms by which Ca2+ controls the activity of acid-sensing ion channel (ASIC) 3. ASICs are neuronal, H+-gated Na+ channels involved in several physiological and pathological processes, including the expression of fear, learning, pain sensation and neurodegeneration after ischaemic stroke. It was previously shown that Ca2+ negatively modulates the ASIC pH dependence. While protons are default activators of ASIC3, this channel can also be activated at pH7.4 by the removal of the extracellular Ca2+. Two previous studies concluded that low pH opens ASIC3 by displacing Ca2+ ions that block the channel pore at physiological pH. We show here that an acidic residue, distant from the pore, together with pore residues, controls the modulation of ASIC3 by Ca2+. Our study identifies a new regulatory site in ASIC3 and demonstrates that ASIC3 activation involves an allosteric mechanism together with Ca2+ unbinding from the channel pore. We provide a molecular analysis of a regulatory mechanism found in many ion channels.


Brain Ischemia , Stroke , Humans , Acid Sensing Ion Channels/genetics , Acid Sensing Ion Channels/chemistry , Acid Sensing Ion Channels/metabolism , Protons , Calcium/metabolism , Allosteric Site , Hydrogen-Ion Concentration , Ions
4.
Fundam Clin Pharmacol ; 36(6): 1128-1132, 2022 Dec.
Article En | MEDLINE | ID: mdl-35801616

In France, the abuse/misuse of psychoactive substances, including cocaine, is monitored via spontaneous notifications, and under-reporting is its main limitation. Therefore, the French national hospital discharge database (Programme de Médicalisation des Systèmes d'information [PMSI]) was used to identify all hospital stays possibly due to complications related to cocaine use. The objective was to determine the main trends in the rate of cocaine-related hospitalizations from 2010 to 2019 by age category and by areas. Relevant PMSI data were extracted using the International Classification of Diseases (10th edition). In France, hospitalizations for cocaine-related complications increased by fourfold (2461 in 2010, 9843 in 2019, +300%). This increase was similar in men and women and was observed in each age category. Patients were mainly men (75% in 2010 and in 2019), with a median age of 38.5 and 35.2 years for men and women, respectively, in 2019. Cocaine poisoning in pediatric patients (0-9 years) concerned less than 10 patients in 2010 and 21 patients in 2019. PMSI data analysis shows an overall increase of cocaine-related hospitalizations in France from 2010 to 2019 that can be linked in part to an increasing recreational use. The increase of pediatric cases of cocaine poisoning suggests a trivialization of cocaine consumption.


Cocaine-Related Disorders , Cocaine , Male , Humans , Child , Female , Cocaine-Related Disorders/epidemiology , Hospitalization , International Classification of Diseases , Length of Stay , Databases, Factual , Cocaine/adverse effects , France/epidemiology
5.
Br J Clin Pharmacol ; 88(10): 4646-4653, 2022 10.
Article En | MEDLINE | ID: mdl-35633029

The study aim was to assess the abuse/misuse potential of second-generation antipsychotics (SGAPs) using VigiBase data. We extracted individual case safety reports of "Drug abuse, dependence and withdrawal" involving SGAPs up to June 2018. We assessed disproportionate reporting by calculating the information component, considering the lower end of the 95% credibility interval for the information component (IC025 ), and the proportional reporting ratio. We identified 1683 individual case safety reports recorded as "abuse, dependence and withdrawal" involving SGAPs, mainly quetiapine (n = 1089) and olanzapine (n = 209). The disproportional reporting indicators highlighted an association between "Drug abuse and dependence", and quetiapine, olanzapine and ziprasidone, as indicated by the IC025 (2.263, 0.259 and 1.051, respectively) and proportional reporting ratio values (3.929, 1.020 and 1.334, respectively). The abuse/misuse potential is confirmed for quetiapine and olanzapine and highlighted for the first time for ziprasidone. Physicians should consider these risks when prescribing these antipsychotics, especially to patients with history of drug abuse.


Antipsychotic Agents , Substance-Related Disorders , Antipsychotic Agents/adverse effects , Benzodiazepines/adverse effects , Humans , Olanzapine/adverse effects , Pharmacovigilance , Quetiapine Fumarate/adverse effects , World Health Organization
6.
Br J Clin Pharmacol ; 88(5): 2306-2314, 2022 05.
Article En | MEDLINE | ID: mdl-34859478

AIMS: Community pharmacists could contribute to identify people misusing prescription opioids, which may be associated with hospitalizations, substance use disorders and death. This study investigated prescription opioid misuse in community pharmacy patients and the factors potentially associated with high Prescription Opioid Misuse Index (POMI) scores. METHODS: In this cross-sectional study, pharmacy students asked patients with opioid prescriptions to fill in a questionnaire (including the POMI) in community pharmacies in a French region, in April 2019. Eligible patients were adults with chronic non-cancer pain who consented to participate. RESULTS: In total, 414 patients (62.4% women; mean age: 58.00 years ± 16.00) were included. The prescribed opioids were mainly weak opioids (73.2%; paracetamol/tramadol: 35%). Strong opioids (32.6%) included oxycodone (11.95%), fentanyl (9%) and morphine (9%). The median morphine milligram equivalent (MME) was 40 mg/day (IQR25-75 : 20-80). The POMI score (0 to 6) was ≥4 in 16% of patients who were younger (P < .01), more urban (P = .03), with higher pain visual analogue scale (VAS) score (P < .01) and MME (P < .01), and treated more frequently with strong opioids (P = .04). In multivariate analysis, age (ORfor 10y : 0.68 (95% CI: 0.56-0.82, P < .0001)), VAS (OR2units : 1.78 (95% CI: 1.26-2.40, P = .0008)), and MME (>100 mg, OR: 2.65 (95% CI: 1.14-4.41, P = .0194)) were significantly associated with POMI scores ≥4. CONCLUSIONS: The high proportion of patients with high POMI scores underlines the interest of prescription opioid misuse screening in community pharmacies, in order to help these patients and refer them to pain specialists, if needed.


Chronic Pain , Opioid-Related Disorders , Pharmacies , Adult , Analgesics, Opioid/adverse effects , Chronic Pain/drug therapy , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Morphine , Opioid-Related Disorders/drug therapy , Opioid-Related Disorders/epidemiology
7.
J Psychoactive Drugs ; 54(4): 386-391, 2022.
Article En | MEDLINE | ID: mdl-34930090

Pregabalin is indicated for the treatment of partial epilepsy, generalized anxiety disorder, and neuropathic pain. The first reports on pregabalin use disorder have been published in Europe in 2010 and notified to the French Addictovigilance Network (FAN) in 2011. The management of pregabalin use disorder is challenging due to the risks associated with the abrupt withdrawal and lack of guidelines. In this retrospective observational study, the management of pregabalin use disorder was analyzed in eight cases reported to the addictovigilance center of Montpellier, France, between 2019 and 2020. Most of these patients had a history of illicit psychoactive substance use. During the withdrawal period, patients experienced mainly psychiatric problems, nervous system symptoms, general disorders, and gastrointestinal symptoms. Multiple strategies were proposed for these patients to manage pregabalin withdrawal, such as hospitalization and pregabalin gradual dose reduction with or without adjuvant medications. Two patients relapsed and the others were lost to follow up. Although other reports of pregabalin use disorder have been published, recommendations or guidelines for its management are not yet available. The current case series and the previous reports suggest that the use of adjunctive therapy may be useful to limit the risk of convulsions and anxiety.


Neuralgia , Substance-Related Disorders , Humans , Pregabalin/adverse effects , Analgesics/adverse effects , Neuralgia/drug therapy , Anxiety Disorders , Substance-Related Disorders/drug therapy
8.
Front Cell Dev Biol ; 9: 639022, 2021.
Article En | MEDLINE | ID: mdl-34386488

Several studies have established the crucial role of the extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase pathway in hematopoietic cell proliferation and differentiation. MEK1 and MEK2 phosphorylate and activate ERK1 and ERK2. However, whether MEK1 and MEK2 differentially regulate these processes is unknown. To define the function of Mek genes in the activation of the ERK pathway during hematopoiesis, we generated a mutant mouse line carrying a hematopoietic-specific deletion of the Mek1 gene function in a Mek2 null background. Inactivation of both Mek1 and Mek2 genes resulted in death shortly after birth with a severe anemia revealing the essential role of the ERK pathway in erythropoiesis. Mek1 and Mek2 functional ablation also affected lymphopoiesis and myelopoiesis. In contrast, mice that retained one functional Mek1 (1Mek1) or Mek2 (1Mek2) allele in hematopoietic cells were viable and fertile. 1Mek1 and 1Mek2 mutants showed mild signs of anemia and splenomegaly, but the half-life of their red blood cells and the response to erythropoietic stress were not altered, suggesting a certain level of Mek redundancy for sustaining functional erythropoiesis. However, subtle differences in multipotent progenitor distribution in the bone marrow were observed in 1Mek1 mice, suggesting that the two Mek genes might differentially regulate early hematopoiesis.

9.
Therapie ; 76(6): 539-547, 2021.
Article En | MEDLINE | ID: mdl-34183194

AIM OF THE STUDY: To describe bacterial infections in injection drug users (IDUs) hospitalized at Montpellier University Hospital, France, and to identify factors that might influence the development of local or systemic infections. METHODS: This cross-sectional observational monocentric study prospectively included bacterial infections in IDUs hospitalized at Montpellier University Hospital between 2012 and 2018. Types of infection (local or systemic) were described and compared to identify specific features (injection practices). RESULTS: The study included 144 bacterial infections (56% of local infections and 44% of systemic infections) concerning 117 IDUs. The most common infection types were abscesses (50%), skin and soft tissue infections (33%), bacteremia/sepsis (20%), endocarditis (17%), and bone and joint infections (16%). Patients were mainly men (n=94; 80%), and the median age was 40 years [IQR25-75: 34-47]. Four deaths related to systemic infection were reported. The most frequent injected substances were cocaine, opioid maintenance treatments (OMT), and opioids. According to the multivariate analysis, factors associated with the occurrence of systemic infections were number of injection (OR 2.59 [1.07-6.27]; P=0.034) and injection of at least one opioid (OR 3.52 [1.28-9.72]; P=0.015). CONCLUSION: Different types of bacterial infections, local or systemic, are observed in IDUs. Skin infections are quite common, but other infection types also are reported, with sometimes serious consequences. It is already known that injection practices are contributing factors in infection development, but the type of injected psychoactive substance(s) also may have an influence.


Bacterial Infections , Substance Abuse, Intravenous , Adult , Cross-Sectional Studies , France/epidemiology , Hospitals, University , Humans , Male , Substance Abuse, Intravenous/epidemiology
10.
Bioorg Med Chem Lett ; 30(21): 127574, 2020 11 01.
Article En | MEDLINE | ID: mdl-32980512

The NO-sGC-cGMP signaling pathway plays an important role in the cardiovascular system. Loss of nitric oxide tone or impaired signaling has been associated with cardiovascular diseases, such as hypertension, pulmonary hypertension and heart failure. Direct activation of sGC enzyme independent of NO represents a novel approach for modulating NO signaling with tremendous therapeutic potential. Herein, we describe the design of a structurally novel class of heme-dependent sGC stimulators containing the 3,3-dimethylpyrrolidin-2-one moiety which resulted in the identification of the potent, selective stimulator 30 (MK-2947) for the treatment of hypertension.


Antihypertensive Agents/pharmacology , Drug Discovery , Hypertension/drug therapy , Soluble Guanylyl Cyclase/metabolism , Antihypertensive Agents/chemistry , Dose-Response Relationship, Drug , Humans , Molecular Structure , Structure-Activity Relationship
11.
Eur J Med Genet ; 63(8): 103956, 2020 Aug.
Article En | MEDLINE | ID: mdl-32439619

In recent years, the introduction of novel genome analysis technologies (such as array comparative genomic hybridization) has enabled the prenatal diagnosis of various recurrent copy number variations (CNVs). Some of these CNVs have been linked to a greater susceptibility of developmental and neuropsychiatric disorders; for example, recurrent duplication at the 2q13 locus is associated with developmental delay, dysmorphism and intellectual disability. However, this CNV has low penetrance and variable clinical expressivity. It also can be observed in healthy controls and can be transmitted by unaffected parents, making genetic counseling especially challenging. Here, we report on the inheritance of a 2q13 duplication in an asymptomatic family; the case highlights the role of the family survey in genetic counseling with regard to novel CNVs diagnosed before birth.


Chromosome Disorders/genetics , Chromosome Duplication , Chromosomes, Human, Pair 2/genetics , Genetic Carrier Screening/methods , Genetic Counseling/methods , Prenatal Diagnosis/methods , Adult , Asymptomatic Diseases , Child, Preschool , Chromosome Disorders/diagnosis , Female , Genetic Carrier Screening/standards , Genetic Counseling/standards , Humans , Male , Pedigree , Prenatal Diagnosis/standards
12.
Sci Rep ; 10(1): 483, 2020 01 16.
Article En | MEDLINE | ID: mdl-31949289

To test the hypothesis that postural control would be more affected by plantar flexors fatigue during acute exposure in hypobaric (HH) than in normobaric (NH) hypoxia or normobaric normoxia (NN). Twelve young male adults performed in a random order three experimental sessions (in HH and NH (FiO2 0.139) at an altitude of 2950 m, and in NN at 500 m) composed of a bipedal postural control with eyes open on a posturographic platform before and after a plantar flexors fatiguing protocol. Center of pressure (CoP) trajectory and stabilogramm diffusion analyses (SDA) parameters were assessed. A two-way repeated measures analysis of variance was used to identify differences by examination of the group and time interaction. Surface of CoP trajectory analysis, increased at POST in HH (p < 0.001) and in NH (p < 0.01) compared to NN. SDA confirmed that PC was more altered in HH than in NH (p < 0.001) and NN (p < 0.05) at POST. The plantar flexor fatigue-induced alteration in postural control increased to a larger extent in HH than in NH or NN, suggesting an alleviating influence of the decreased barometric pressure per se and a mechanical influence of the higher breathing frequency in HH.


Altitude , Hypoxia/physiopathology , Muscle Fatigue , Oxygen/metabolism , Postural Balance , Adult , Atmospheric Pressure , Humans , Male , Young Adult
15.
Sci Rep ; 9(1): 2599, 2019 02 22.
Article En | MEDLINE | ID: mdl-30796301

Modulation by neuropeptides enhances several functions of acid-sensing ion channels (ASICs), such as pain sensation and acid-induced neuronal injury. The acid-induced opening of ASICs is transient, because of a rapid desensitization. Neuropeptides containing an Arg-Phe-amide motif affect ASIC desensitization and allow continuous activity of ASICs. In spite of the importance of the sustained ASIC activity during prolonged acidification, the molecular mechanisms of ASIC modulation by neuropeptides is only poorly understood. To identify the FRRFa (Phe-Arg-Arg-Phe-amide) binding site on ASIC1a, we carried out an in silico docking analysis and verified functionally the docking predictions. The docking experiments indicated three possible binding pockets, located (1) in the acidic pocket between the thumb, finger, ß-ball and palm domains, (2) in a pocket at the bottom of the thumb domain, and (3) in the central vestibule along with the connected side cavities. Functional measurements of mutant ASIC1a confirmed the importance of residues of the lower palm, which encloses the central vestibule and its side cavities, for the FRRFa effects. The combined docking and functional experiments strongly suggest that FRRFa binds to the central vestibule and its side cavities to change ASIC desensitization.


Acid Sensing Ion Channels , Dipeptides/metabolism , Neuropeptides/metabolism , Acid Sensing Ion Channels/chemistry , Acid Sensing Ion Channels/metabolism , Animals , Binding Sites , Molecular Docking Simulation/methods , Oocytes , Protein Binding , Protein Domains , Xenopus laevis
16.
J Clin Endocrinol Metab ; 103(7): 2601-2612, 2018 07 01.
Article En | MEDLINE | ID: mdl-29726959

Context: The hypothalamic melanocortin 4 receptor (MC4R) pathway serves a critical role in regulating body weight. Loss of function (LoF) mutations in the MC4R pathway, including mutations in the pro-opiomelanocortin (POMC), prohormone convertase 1 (PCSK1), leptin receptor (LEPR), or MC4R genes, have been shown to cause early-onset severe obesity. Methods: Through a comprehensive epidemiological analysis of known and predicted LoF variants in the POMC, PCSK1, and LEPR genes, we sought to estimate the number of US individuals with biallelic MC4R pathway LoF variants. Results: We predict ~650 α-melanocyte-stimulating hormone (MSH)/POMC, 8500 PCSK1, and 3600 LEPR homozygous and compound heterozygous individuals in the United States, cumulatively enumerating >12,800 MC4R pathway-deficient obese patients. Few of these variants have been genetically diagnosed to date. These estimates increase when we include a small subset of less rare variants: ß-MSH/POMC,PCSK1 N221D, and a PCSK1 LoF variant (T640A). To further define the MC4R pathway and its potential impact on obesity, we tested associations between body mass index (BMI) and LoF mutation burden in the POMC, PCSK1, and LEPR genes in various populations. We show that the cumulative allele burden in individuals with two or more LoF alleles in one or more genes in the MC4R pathway are predisposed to a higher BMI than noncarriers or heterozygous LoF carriers with a defect in only one gene. Conclusions: Our analysis represents a genetically rationalized study of the hypothalamic MC4R pathway aimed at genetic patient stratification to determine which obese subpopulations should be studied to elucidate MC4R agonist (e.g., setmelanotide) treatment responsiveness.


Loss of Function Mutation/genetics , Obesity/epidemiology , Obesity/genetics , Receptor, Melanocortin, Type 4/genetics , Signal Transduction/genetics , Alleles , Anti-Obesity Agents/pharmacology , Body Mass Index , Female , Heterozygote , Homozygote , Humans , Male , Obesity/drug therapy , Pro-Opiomelanocortin/genetics , Proprotein Convertase 1/genetics , Receptor, Melanocortin, Type 4/agonists , Receptors, Leptin/genetics , United States/epidemiology , alpha-MSH/analogs & derivatives , alpha-MSH/pharmacology
17.
Am J Obstet Gynecol ; 218(3): 341.e1-341.e9, 2018 Mar.
Article En | MEDLINE | ID: mdl-29291413

BACKGROUND: The dramatic rise in cesarean delivery rates worldwide in recent decades, without evidence of a concomitant decrease in cerebral palsy rates, has raised concerns about its potential negative consequences for maternal and infant health. In 2014, the American College of Obstetricians and Gynecologists and the Society for Maternal-Fetal Medicine jointly published an Obstetric Care Consensus for safe prevention of the primary cesarean delivery. OBJECTIVE: We sought to assess whether modification of our protocol to implement these recommendations helped to decrease our primary cesarean delivery rate safely. STUDY DESIGN: This is a before-and-after retrospective cohort study at a university referral hospital. In March 2014, the threshold for defining active labor changed from 4 to >6 cm and arrest of first-stage labor from lack of cervical change despite regular contractions after 3 hours of oxytocin administration with amniotomy and epidural anesthesia to no change after 4 hours of adequate or 6 hours of inadequate contractions in women with an epidural. The definition of second-stage arrest of labor changed simultaneously from lack of progress for 3 hours with adequate contractions in women with epidural anesthesia to no progress for ≥4 hours in nulliparas or 3 hours in multiparas with an epidural. We compared maternal and neonatal outcomes over two 1 year periods: from March 2013 to February 2014 (before, preguideline) and from June 2014 to May 2015 (after, postguideline). We included all women with singleton pregnancies at ≥37 weeks' gestation, in vertex presentation, in spontaneous or induced labor, and with epidural anesthesia. We excluded women with an elective or previous cesarean delivery and those with obstetric or fetal complications. RESULTS: This study included 3283 and 3068 women in the before and after periods, respectively. The groups had similar general and obstetric characteristics. The global cesarean delivery rate decreased significantly from 9.4% in the preguideline to 6.9% in the postguideline period (odds ratio, 0.71; 95% confidence interval, 0.59-0.85; P < .01). The cesarean delivery rate for arrest of first-stage labor fell by half, from 1.8% to 0.9% (odds ratio, 0.51; 95% confidence interval, 0.31-0.81; P < .01) but was significant only among nulliparous women. The cesarean delivery rate for second-stage arrest of labor decreased but not significantly between periods (1.3% vs 1.0%; odds ratio, 0.73; 95% confidence interval, 0.44-1.22; P = .2), and the cesarean delivery rate for failure of induction remained similar (3.7% vs 3.5%; odds ratio, 1.06; 95% confidence interval, 0.06-13.24; P = .88). The median duration of labor before cesarean delivery also became significantly longer among nulliparous women during the later period. Maternal and neonatal outcomes did not differ between the 2 periods, except that the rate of 1 minute Apgar score <7 fell significantly in the later period (8.4% vs 6.9%; odds ratio, 0.80; 95% confidence interval, 0.66-0.97; P = .02). CONCLUSION: The modification of our protocol by implementing the new consensus recommendations was associated with a reduction of the rate of primary cesarean delivery performed for arrest of labor with no apparent increase in immediate adverse neonatal outcomes in nulliparous women at term with singleton pregnancies in vertex presentation and with epidural anesthesia. Further studies are needed to assess the long-term maternal and neonatal safety of these policies.


Cesarean Section/statistics & numerical data , Labor, Obstetric , Obstetric Labor Complications/diagnosis , Obstetric Labor Complications/surgery , Adult , Clinical Protocols , Female , Humans , Interrupted Time Series Analysis , Labor Stage, First , Labor Stage, Second , Labor, Induced , Parity , Practice Guidelines as Topic , Pregnancy , Retrospective Studies
18.
Bioorg Med Chem Lett ; 27(11): 2559-2566, 2017 06 01.
Article En | MEDLINE | ID: mdl-28431879

SAR in the previously described spirocyclic ROMK inhibitor series was further evolved from lead 4 by modification of the spirocyclic core and identification of novel right-side pharmacophores. In this process, it was discovered that the spiropyrrolidinone core with the carbonyl group α to the spirocenter was preferred for potent ROMK activity. Efforts aimed at decreasing hERG affinity within the series led to the discovery of multiple novel right-hand pharmacophores including 3-methoxythiadiazole, 2-methoxypyrimidine, and pyridazinone. The most promising candidate is pyridazinone analog 32 that showed an improved functional hERG/ROMK potency ratio and preclinical PK profile. In vivo evaluation of 32 demonstrated blood pressure lowering effects in the spontaneously hypertensive rat model.


ERG1 Potassium Channel/metabolism , Potassium Channel Blockers/chemistry , Potassium Channels, Inwardly Rectifying/antagonists & inhibitors , Animals , Disease Models, Animal , Dogs , ERG1 Potassium Channel/antagonists & inhibitors , Half-Life , Hypertension/drug therapy , Potassium Channel Blockers/pharmacokinetics , Potassium Channel Blockers/therapeutic use , Potassium Channels, Inwardly Rectifying/metabolism , Pyrimidines/chemistry , Rats , Rats, Inbred SHR , Spiro Compounds/chemistry , Structure-Activity Relationship , Thiadiazoles/chemistry
19.
Proc Natl Acad Sci U S A ; 114(14): 3768-3773, 2017 04 04.
Article En | MEDLINE | ID: mdl-28320963

Acid-sensing ion channels (ASICs) are proton-activated Na+ channels expressed in the nervous system, where they are involved in learning, fear behaviors, neurodegeneration, and pain sensation. In this work, we study the role in pH sensing of two regions of the ectodomain enriched in acidic residues: the acidic pocket, which faces the outside of the protein and is the binding site of several animal toxins, and the palm, a central channel domain. Using voltage clamp fluorometry, we find that the acidic pocket undergoes conformational changes during both activation and desensitization. Concurrently, we find that, although proton sensing in the acidic pocket is not required for channel function, it does contribute to both activation and desensitization. Furthermore, protonation-mimicking mutations of acidic residues in the palm induce a dramatic acceleration of desensitization followed by the appearance of a sustained current. In summary, this work describes the roles of potential pH sensors in two extracellular domains, and it proposes a model of acidification-induced conformational changes occurring in the acidic pocket of ASIC1a.


Acid Sensing Ion Channels/chemistry , Acid Sensing Ion Channels/metabolism , Sodium/metabolism , Toxins, Biological/metabolism , Acid Sensing Ion Channels/genetics , Binding Sites , Humans , Hydrogen-Ion Concentration , Models, Molecular , Mutation , Protein Structure, Tertiary
20.
Bioorg Med Chem Lett ; 26(23): 5695-5702, 2016 12 01.
Article En | MEDLINE | ID: mdl-27839686

Following the discovery of small molecule acyl piperazine ROMK inhibitors, the acyl octahydropyrazino[2,1-c][1,4]oxazine series was identified. This series displays improved ROMK/hERG selectivity, and as a consequence, the resulting ROMK inhibitors do not evoke QTc prolongation in an in vivo cardiovascular dog model. Further efforts in this series led to the discovery of analogs with improved pharmacokinetic profiles. This new series also retained comparable ROMK potency compared to earlier leads.


Oxazines/chemistry , Oxazines/pharmacology , Potassium Channels, Inwardly Rectifying/antagonists & inhibitors , Animals , Diuresis/drug effects , Dogs , Heart Failure/drug therapy , Humans , Hypertension/drug therapy , Macaca mulatta , Oxazines/pharmacokinetics , Potassium Channels, Inwardly Rectifying/metabolism , Rats, Sprague-Dawley , Transcriptional Regulator ERG/antagonists & inhibitors , Transcriptional Regulator ERG/metabolism
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