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Glycine Transporter 2 (GlyT2) inhibitors have shown considerable potential as analgesics for the treatment of neuropathic pain but also display considerable side effects. One potential source of side effects is irreversible inhibition. In this study, we have characterized the mechanism of ORG25543 inhibition of GlyT2 by first considering three potential ligand binding sites on GlyT2-the substrate site, the vestibule allosteric site and the lipid allosteric site. The three sites were tested using a combination of molecular dynamics simulations and analysis of the inhibition of glycine transport of a series point mutated GlyT2 using electrophysiological methods. We demonstrate that the lipid allosteric site on GlyT2 is the most likely binding site for ORG25543. We also demonstrate that cholesterol derived from the cell membrane can form specific interactions with inhibitor-bound transporters to form an allosteric network of regulatory sites. These observations will guide the future design of GlyT2 inhibitors with the objective of minimising on-target side effects and improving the therapeutic window for the treatment of patients suffering from neuropathic pain., (© 2023 The Authors. Journal of Neurochemistry published by John Wiley & Sons Ltd on behalf of International Society for Neurochemistry.)

Proline is widely known as the only proteogenic amino acid with a secondary amine. In addition to its crucial role in protein structure, the secondary amino acid modulates neurotransmission and regulates the kinetics of signaling proteins. To understand the structural basis of proline import, we solved the structure of the proline transporter SIT1 in complex with the COVID-19 viral receptor ACE2 by cryo-electron microscopy. The structure of pipecolate-bound SIT1 reveals the specific sequence requirements for proline transport in the SLC6 family and how this protein excludes amino acids with extended side chains. By comparing apo and substrate-bound SIT1 states, we also identify the structural changes that link substrate release and opening of the cytoplasmic gate and provide an explanation for how a missense mutation in the transporter causes iminoglycinuria., (© 2024. The Author(s).)

Zinc is a ubiquitous contaminant in many buffers, purified products and common labware that has previously been suggested to impact on the results of functional GlyR studies and may inadvertently cause the effectiveness of some GlyR modulators to be over-estimated. This could greatly impact the assessment of potential drug-candidates and contribute to the reduced effectiveness of compounds that reach clinical stages. This is especially true for GlyR modulators being developed for pain therapeutics due to the changes in spinal zinc concentrations that have been observed during chronic pain conditions. In this study we use two-electrode voltage clamp electrophysiology to evaluate the metal chelators tricine and Ca-EDTA, and show that tricine produces inhibitory effects at GlyRα 1 that are not mediated by zinc. We also utilized the zinc insensitive W170S mutation as a tool to validate metal chelators and confirm that zinc contamination has not impacted the examination of lipid modulators previously developed by our lab. This study helps to further develop methods to negate the impact of contaminating zinc in functional studies of GlyRs which should be incorporated into future studies that seek to characterize the activity of novel modulators at GlyRs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Gallagher, Bishop, Lockwood, Rawling and Vandenberg.)

The multi-messenger detection of the gravitational-wave signal GW170817, the corresponding kilonova AT2017gfo and the short gamma-ray burst GRB170817A, as well as the observed afterglow has delivered a scientific breakthrough. For an accurate interpretation of all these different messengers, one requires robust theoretical models that describe the emitted gravitational-wave, the electromagnetic emission, and dense matter reliably. In addition, one needs efficient and accurate computational tools to ensure a correct cross-correlation between the models and the observational data. For this purpose, we have developed the Nuclear-physics and Multi-Messenger Astrophysics framework NMMA. The code allows incorporation of nuclear-physics constraints at low densities as well as X-ray and radio observations of isolated neutron stars. In previous works, the NMMA code has allowed us to constrain the equation of state of supranuclear dense matter, to measure the Hubble constant, and to compare dense-matter physics probed in neutron-star mergers and in heavy-ion collisions, and to classify electromagnetic observations and perform model selection. Here, we show an extension of the NMMA code as a first attempt of analyzing the gravitational-wave signal, the kilonova, and the gamma-ray burst afterglow simultaneously. Incorporating all available information, we estimate the radius of a 1.4M ⊙ neutron star to be [Formula: see text] km., (© 2023. The Author(s).)

Chronic pain is a complex condition that remains resistant to current therapeutics. We previously synthesized a series of N -acyl amino acids (NAAAs) that inhibit the glycine transporter, GlyT2, some of which are also positive allosteric modulators of glycine receptors (GlyRs). In this study, we have synthesized a library of NAAAs that contain a phenylene ring within the acyl tail with the objective of improving efficacy at both GlyT2 and GlyRs and also identifying compounds that are efficacious as dual-acting modulators to enhance glycine neurotransmission. The most efficacious positive allosteric modulator of GlyRs was 2-[8-(2-octylphenyl)octanoylamino]acetic acid (8-8 OPGly) which potentiates the EC 5 for glycine activation of GlyRα 1 by 1500% with an EC 50 of 664 nM. Phenylene-containing NAAAs with a lysine headgroup were the most potent inhibitors of GlyT2 with (2 S )-6-amino-2-[8-(3-octylphenyl)octanoylamino]hexanoic acid (8-8 MPLys) inhibiting GlyT2 with an IC 50 of 32 nM. The optimal modulator across both proteins was (2 S )-6-amino-2-[8-(2-octylphenyl)octanoylamino]hexanoic acid (8-8 OPLys), which inhibits GlyT2 with an IC 50 of 192 nM and potentiates GlyRs by up to 335% at 1 μM. When tested in a dual GlyT2/GlyRα 1 expression system, 8-8 OPLys caused the greatest reductions in the EC 50 for glycine. This suggests that the synergistic effects of a dual-acting modulator cause greater enhancements in glycinergic activity compared to single-target modulators and may provide an alternate approach to the development of new non-opioid analgesics for the treatment of chronic pain.

Membrane cholesterol binds to and modulates the function of various SLC6 neurotransmitter transporters, including stabilizing the outward-facing conformation of the dopamine and serotonin transporters. Here, we investigate how cholesterol binds to GlyT2 (SLC6A5), modulates glycine transport rate, and influences bioactive lipid inhibition of GlyT2. Bioactive lipid inhibitors are analgesics that bind to an allosteric site accessible from the extracellular solution when GlyT2 adopts an outward-facing conformation. Using molecular dynamics simulations, mutagenesis, and cholesterol depletion experiments, we show that bioactive lipid inhibition of glycine transport is modulated by the recruitment of membrane cholesterol to a binding site formed by transmembrane helices 1, 5, and 7. Recruitment involves cholesterol flipping from its membrane orientation, and insertion of the 3' hydroxyl group into the cholesterol binding cavity, close to the allosteric site. The synergy between cholesterol and allosteric inhibitors provides a novel mechanism of inhibition and a potential avenue for the development of potent GlyT2 inhibitors as alternative therapeutics for the treatment of neuropathic pain and therapeutics that target other SLC6 transporters., (© 2023 Frangos et al.)

Glycine receptors are ligand-gated ion channels that mediate synaptic inhibition throughout the mammalian spinal cord, brainstem, and higher brain regions. They have recently emerged as promising targets for novel pain therapies due to their ability to produce antinociception by inhibiting nociceptive signals within the dorsal horn of the spinal cord. This has greatly enhanced the interest in developing positive allosteric modulators of glycine receptors. Several pharmaceutical companies and research facilities have attempted to identify new therapeutic leads by conducting large-scale screens of compound libraries, screening new derivatives from natural sources, or synthesizing novel compounds that mimic endogenous compounds with antinociceptive activity. Advances in structural techniques have also led to the publication of multiple high-resolution structures of the receptor, highlighting novel allosteric binding sites and providing additional information for previously identified binding sites. This has greatly enhanced our understanding of the functional properties of glycine receptors and expanded the structure activity relationships of novel pharmacophores. Despite this, glycine receptors are yet to be used as drug targets due to the difficulties in obtaining potent, selective modulators with favorable pharmacokinetic profiles that are devoid of side effects. This review presents a summary of the structural basis for how current compounds cause positive allosteric modulation of glycine receptors and discusses their therapeutic potential as analgesics. SIGNIFICANCE STATEMENT: Chronic pain is a major cause of disability, and in Western societies, this will only increase as the population ages. Despite the high level of prevalence and enormous socioeconomic burden incurred, treatment of chronic pain remains limited as it is often refractory to current analgesics, such as opioids. The National Institute for Drug Abuse has set finding effective, safe, nonaddictive strategies to manage chronic pain as their top priority. Positive allosteric modulators of glycine receptors may provide a therapeutic option., (Copyright © 2022 by The American Society for Pharmacology and Experimental Therapeutics.)

Background: Despite advances in next generation sequencing technologies, the identification of variants of uncertain significance (VUS) can often hinder definitive diagnosis in patients with complex neurodevelopmental disorders., Objective: The objective of this study was to identify and characterize the underlying cause of disease in a family with two children with severe developmental delay associated with generalized dystonia and episodic status dystonicus, chorea, epilepsy, and cataracts., Methods: Candidate genes identified by autozygosity mapping and whole-exome sequencing were characterized using cellular and vertebrate model systems., Results: Homozygous variants were found in three candidate genes: MED27, SLC6A7, and MPPE1. Although the patients had features of MED27-related disorder, the SLC6A7 and MPPE1 variants were functionally investigated. SLC6A7 variant in vitro overexpression caused decreased proline transport as a result of reduced cell-surface expression, and zebrafish knockdown of slc6a7 exhibited developmental delay and fragile motor neuron morphology that could not be rescued by L-proline transporter-G396S RNA. Lastly, patient fibroblasts displayed reduced cell-surface expression of glycophosphatidylinositol-anchored proteins linked to MPPE1 dysfunction., Conclusions: We report a family harboring a homozygous MED27 variant with additional loss-of-function SLC6A7 and MPPE1 gene variants, which potentially contribute to a blended phenotype caused by multilocus pathogenic variants. © 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society., (© 2022 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.)

The prevalence of chronic health conditions is increasing, with over half the current workforce attempting to manage one or more chronic conditions. The Live Healthy, Work Healthy (LHWH) program is a version of the Chronic Disease Self-Management Program translated to the workplace, with the goal of improving and sustaining the health, well-being, and productivity of employees living with chronic health conditions. Using organizational support theory as a theoretical framework and a clustered randomized controlled trial design, this article demonstrates how the LHWH program positively impacts work-related quality of life, orientations toward the organization, and organizational cognitions and behaviors. Participants in the program experienced increases in perceived organizational support (POS), with a large intervention effect. Direct intervention effects were also found for burnout, work engagement, work ability, affective organizational commitment, and organizational citizenship behaviors. Within-person changes in POS during the intervention was a key mechanism through which participants of the program experienced changes in organizationally relevant outcomes. Finally, offering the program on work time strengthened these effects indirectly through greater changes in POS during the intervention period. This article provides evidence to researchers and organizational decision-makers that offering the LHWH program not only improves the health and well-being of employees but also improves important organizational outcomes. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Aberrations in spinal glycinergic signaling are a feature of pain chronification. Normalizing these changes by inhibiting glycine transporter (GlyT)-2 is a promising treatment strategy. However, existing GlyT2 inhibitors (e.g., ORG25543) are limited by narrow therapeutic windows and severe dose-limiting side effects, such as convulsions, and are therefore poor candidates for clinical development. Here, intraperitoneally administered oleoyl- D -lysine, a lipid-based GlyT2 inhibitor, was characterized in mouse models of acute (hot plate), inflammatory (complete Freund's adjuvant), and chronic neuropathic (chronic constriction injury) pain. Side effects were also assessed on a numerical rating score, convulsions score, for motor incoordination (rotarod), and for respiratory depression (whole body plethysmography). Oleoyl- D -lysine produced near complete antiallodynia for chronic neuropathic pain, but no antiallodynia/analgesia in inflammatory or acute pain. No side effects were seen at the peak analgesic dose, 30 mg/kg. Mild side effects were observed at the highest dose, 100 mg/kg, on the numerical rating score, but no convulsions. These results contrasted markedly with ORG25543, which reached less than 50% reduction in allodynia score only at the lethal/near-lethal dose of 50 mg/kg. At this dose, ORG25543 caused maximal side effects on the numerical rating score and severe convulsions. Oleoyl- D -lysine (30 mg/kg) did not cause any respiratory depression, a problematic side effect of opiates. These results show the safe and effective reversal of neuropathic pain in mice by oleoyl- D -lysine and provide evidence for a distinct role of glycine in chronic pain over acute or short-term pain conditions. SIGNIFICANCE STATEMENT: Partially inhibiting glycine transporter (GlyT)-2 can alleviate chronic pain by restoring lost glycinergic function. Novel lipid-based GlyT2 inhibitor ol- D -lys is safe and effective in alleviating neuropathic pain, but not inflammatory or acute pain. Clinical application of GlyT2 inhibitors may be better suited to chronic neuropathic pain over other pain aetiologies., (Copyright © 2022 by The American Society for Pharmacology and Experimental Therapeutics.)

Animal models of human pain conditions allow for detailed interrogation of known and hypothesized mechanisms of pain physiology in awake, behaving organisms. The importance of the glycinergic system for pain modulation is well known; however, manipulation of this system to treat and alleviate pain has not yet reached the sophistication required for the clinic. Here, we review the current literature on what animal behavioral studies have allowed us to elucidate about glycinergic pain modulation, and the progress toward clinical treatments so far. First, we outline the animal pain models that have been used, such as nerve injury models for neuropathic pain, chemogenic pain models for acute and inflammatory pain, and other models that mimic painful human pathologies such as diabetic neuropathy. We then discuss the genetic approaches to animal models that have identified the crucial glycinergic machinery involved in neuropathic and inflammatory pain. Specifically, two glycine receptor (GlyR) subtypes, GlyRα1(β) and GlyRα3(β), and the two glycine transporters (GlyT), GlyT1 and GlyT2. Finally, we review the different pharmacological approaches to manipulating the glycinergic system for pain management in animal models, such as partial vs . full agonism, reversibility, and multi-target approaches. We discuss the benefits and pitfalls of using animal models in drug development broadly, as well as the progress of glycinergic treatments from preclinical to clinical trials., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Peiser-Oliver, Evans, Adams, Christie, Vandenberg and Mohammadi.)

Neurotransmitter sodium symporters (NSS) are a subfamily of SLC6 transporters responsible for regulating neurotransmitter signalling. They are a major target for psychoactive substances including antidepressants and drugs of abuse, prompting substantial research into their modulation and structure-function dynamics. Recently, a series of allosteric transport inhibitors have been identified, which may reduce side effect profiles, compared to orthosteric inhibitors. Allosteric inhibitors are also likely to provide different clearance kinetics compared to competitive inhibitors and potentially better clinical outcomes. Crystal structures and homology models have identified several allosteric modulatory sites on NSS including the vestibule allosteric site (VAS), lipid allosteric site (LAS) and cholesterol binding site (CHOL1). Whilst the architecture of eukaryotic NSS is generally well conserved there are differences in regions that form the VAS, LAS, and CHOL1. Here, we describe ligand-protein interactions that stabilize binding in each allosteric site and explore how differences between transporters could be exploited to generate NSS specific compounds with an emphasis on GlyT2 modulation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Frangos, Cantwell Chater and Vandenberg.)

Background . FUEL Your Life (FYL) is a worksite translation of the Diabetes Prevention Program (DPP). In a randomized controlled trial, participants in a phone coaching condition demonstrated greater weight loss compared to participants in a group coaching or self-study condition. The purpose of this article is to describe the differences in participant reach, intervention uptake, and participant satisfaction for each delivery mode. Method . Employees who were overweight, obese, or at high risk for diabetes were recruited from city-county governments. Process evaluation data were collected from health coach records, participant surveys, and research team records. Differences between groups were tested using Pearson chi-square test and one-way analysis of variance. Results . Employee reach of targeted enrollment was highest for the self-study condition. Overall, intervention uptake was highest in the phone coaching condition. Participants who received phone coaching had increased uptake of the participant manual and self-monitoring of food compared to participants who received group coaching or self-study. Discussion . FYL demonstrated that DPP could be effectively delivered in the worksite by three different modalities. When implemented in a self-study mode, reach is greater but intervention uptake is lower. Phone health coaching was associated with greater intervention exposure.

Purpose: Report the results of a randomized, controlled trial of Live Healthy, Work Healthy (LHWH), a worksite translation of the Chronic Disease Self-Management Program (CDSMP)., Design: 14 worksites were randomly assigned to LHWH, standard CDSMP (usual care) or no-intervention (control) group., Setting: The diverse set of work organizations centered around a rural community in SE US., Subjects: 411 participants completed baseline data with 359 being included in the final analyses., Intervention: LHWH had been adapted to fit the unique characteristics of work organizations. This translated program consists of 15 sessions over 8 weeks and was facilitated by trained lay leaders., Measures: The primary outcomes including health risk, patient-provider communication, quality of life, medical adherence and work performance were collected pretest, posttest (6 mos.) and follow-up (12 mos.)., Analysis: Analyses were conducted using latent change score models in a structural equation modeling framework., Results: 79% of participants reported at least one chronic condition with an average of 2.7 chronic conditions reported. Results indicated that LHWH program demonstrated positive changes in a most outcomes including significant exercise (uΔ = 0.89, p < .01), chronic disease self-efficacy (uΔ = 0.63, p < .05), fatigue (uΔ = -1.45, p < .05), stress (uΔ = -0.98, p < .01) and mentally unhealthy days (uΔ = -3.47, p < .001)., Conclusions: The translation of LHWH is an effective, low cost, embeddable program that has the potential to improve the health and work life of employees.

The purpose of this study was to evaluate the relationship between workload, exhaustion, and key health behaviors for weight loss-nutrition and physical activity. Structural equation modeling was used to estimate the path coefficients in a sample of 953 employed adults. The results show that workload and exhaustion were positively related to emotional eating, uncontrolled eating, and percent of calories from fat. In addition, exhaustion was negatively related to physical activity levels. Workload and exhaustion are associated with nutrition and physical activity behaviors that promote weight gain and should be considered in weight management interventions for working adults.

Glutamate is the most abundant excitatory neurotransmitter in the central nervous system, and its precise control is vital to maintain normal brain function and to prevent excitotoxicity 1 . The removal of extracellular glutamate is achieved by plasma-membrane-bound transporters, which couple glutamate transport to sodium, potassium and pH gradients using an elevator mechanism 2-5 . Glutamate transporters also conduct chloride ions by means of a channel-like process that is thermodynamically uncoupled from transport 6-8 . However, the molecular mechanisms that enable these dual-function transporters to carry out two seemingly contradictory roles are unknown. Here we report the cryo-electron microscopy structure of a glutamate transporter homologue in an open-channel state, which reveals an aqueous cavity that is formed during the glutamate transport cycle. The functional properties of this cavity, combined with molecular dynamics simulations, reveal it to be an aqueous-accessible chloride permeation pathway that is gated by two hydrophobic regions and is conserved across mammalian and archaeal glutamate transporters. Our findings provide insight into the mechanism by which glutamate transporters support their dual function, and add information that will assist in mapping the complete transport cycle shared by the solute carrier 1A transporter family.

The role of lipids in modulating membrane protein function is an emerging and rapidly growing area of research. The rational design of lipids that target membrane proteins for the treatment of pathological conditions is a novel extension in this field and provides a step forward in our understanding of membrane transporters. Bioactive lipids show considerable promise as analgesics for the treatment of chronic pain and bind to a high-affinity allosteric-binding site on the human glycine transporter 2 (GlyT2 or SLC6A5). Here, we use a combination of medicinal chemistry, electrophysiology, and computational modeling to develop a rational structure-activity relationship for lipid inhibitors and demonstrate the key role of the lipid tail interactions for GlyT2 inhibition. Specifically, we examine how lipid inhibitor head group stereochemistry, tail length, and double-bond position promote enhanced inhibition. Overall, the l-stereoisomer is generally a better inhibitor than the d-stereoisomer, longer tail length correlates with greater potency, and the position of the double bond influences the activity of the inhibitor. We propose that the binding of the lipid inhibitor deep into the allosteric-binding pocket is critical for inhibition. Furthermore, this provides insight into the mechanism of inhibition of GlyT2 and highlights how lipids can modulate the activity of membrane proteins by binding to cavities between helices. The principles identified in this work have broader implications for the development of a larger class of compounds that could target SLC6 transporters for disease treatment., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Replication studies play an essential role in corroborating research findings and ensuring that subsequent experimental works are interpreted correctly. A previously published paper indicated that the neurotransmitter glutamate, along with the compounds N -methyl-d-aspartate (NMDA) and d-(-)-2-amino-5-phosphonopentanoic acid (AP5), acts as positive allosteric modulators of inhibitory glycine receptors. The paper further suggested that this form of modulation would play a role in setting the spinal inhibitory tone and influencing sensory signaling, as spillover of glutamate onto nearby glycinergic synapses would permit rapid crosstalk between excitatory and inhibitory synapses. Here, we attempted to replicate this finding in primary cultured spinal cord neurons, spinal cord slice, and Xenopus laevis oocytes expressing recombinant human glycine receptors. Despite extensive efforts, we were unable to reproduce the finding that glutamate, AP5, and NMDA positively modulate glycine receptor currents. We paid careful attention to critical aspects of the original study design and took into account receptor saturation and protocol deviations such as animal species. Finally, we explored possible explanations for the experimental discrepancy. We found that solution contamination with a high-affinity modulator such as zinc is most likely to account for the error, and we suggest methods for preventing this kind of misinterpretation in future studies aimed at characterizing high-affinity modulators of the glycine receptor. SIGNIFICANCE STATEMENT: A previous study indicates that glutamate spillover onto inhibitory synapses can directly interact with glycine receptors to enhance inhibitory signalling. This finding has important implications for baseline spinal transmission and may play a role when chronic pain develops. However, we failed to replicate the results and did not observe glutamate, d-(-)-2-amino-5-phosphonopentanoic acid, or N -methyl-d-aspartate modulation of native or recombinant glycine receptors. We ruled out various sources for the discrepancy and found that the most likely cause is solution contamination., (Copyright © 2020 by The Author(s).)

Reduced inhibitory glycinergic neurotransmission is implicated in a number of neurological conditions such as neuropathic pain, schizophrenia, epilepsy and hyperekplexia. Restoring glycinergic signalling may be an effective method of treating these pathologies. Glycine transporters (GlyTs) control synaptic and extra-synaptic glycine concentrations and slowing the reuptake of glycine using specific GlyT inhibitors will increase glycine extracellular concentrations and increase glycine receptor (GlyR) activation. Glycinergic neurotransmission can also be improved through positive allosteric modulation (PAM) of GlyRs. Despite efforts to manipulate this synapse, no therapeutics currently target it. We propose that dual action modulators of both GlyTs and GlyRs may show greater therapeutic potential than those targeting individual proteins. To show this, we have characterized a co-expression system in Xenopus laevis oocytes consisting of GlyT1 or GlyT2 co-expressed with GlyRα 1 . We use two electrode voltage clamp recording techniques to measure the impact of GlyTs on GlyRs and the effects of modulators of these proteins. We show that increases in GlyT density in close proximity to GlyRs diminish receptor currents. Reductions in GlyR mediated currents are not observed when non-transportable GlyR agonists are applied or when Na + is not available. GlyTs reduce glycine concentrations across different concentration ranges, corresponding with their ion-coupling stoichiometry, and full receptor currents can be restored when GlyTs are blocked with selective inhibitors. We show that partial inhibition of GlyT2 and modest GlyRα 1 potentiation using a dual action compound, is as useful in restoring GlyR currents as a full and potent single target GlyT2 inhibitor or single target GlyRα 1 PAM. The co-expression system developed in this study will provide a robust means for assessing the likely impact of GlyR PAMs and GlyT inhibitors on glycine neurotransmission.

Glycine receptors (GlyRs) mediate inhibitory neurotransmission within the spinal cord and play a crucial role in nociceptive signalling. This makes them primary targets for the development of novel chronic pain therapies. Endogenous lipids have previously been shown to modulate glycine receptors and produce analgesia in pain models, however little is known about what chemical features mediate these effects. In this study, we characterised lipid modulation of GlyRs by screening a library of N-acyl amino acids across all receptor subtypes and determined chemical features crucial for their activity. Acyl-glycine's with a C18 carbon tail were found to produce the greatest potentiation, and require a cis double bond within the central region of the carbon tail (ω6 - ω9) to be active. At 1 µM, C18 ω6,9 glycine potentiated glycine induced currents in α 3 and α 3 β receptors by over 50%, and α 1 , α 2 , α 1 β and α 2 β receptors by over 100%. C18 ω9 glycine (N-oleoyl glycine) significantly enhance glycine induced peak currents and cause a dose-dependent shift in the glycine concentration response. In the presence of 3 µM C18 ω9 glycine, the EC 5o of glycine at the α 1 receptor was reduced from 17 µM to 10 µM. This study has identified several acyl-amino acids which are positive allosteric modulators of GlyRs and make promising lead compounds for the development of novel chronic pain therapies., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The Solute Carrier 1A (SLC1A) family includes two major mammalian transport systems-the alanine serine cysteine transporters (ASCT1-2) and the human glutamate transporters otherwise known as the excitatory amino acid transporters (EAAT1-5). The EAATs play a critical role in maintaining low synaptic concentrations of the major excitatory neurotransmitter glutamate, and hence they have been widely researched over a number of years. More recently, the neutral amino acid exchanger, ASCT2 has garnered attention for its important role in cancer biology and potential as a molecular target for cancer therapy. The nature of this role is still being explored, and several classes of ASCT2 inhibitors have been developed. However none have reached sufficient potency or selectivity for clinical use. Despite their distinct functions in biology, the members of the SLC1A family display structural and functional similarity. Since 2004, available structures of the archaeal homologues Glt Ph and Glt Tk have elucidated mechanisms of transport and inhibition common to the family. The recent determination of EAAT1 and ASCT2 structures may be of assistance in future efforts to design efficacious ASCT2 inhibitors. This review will focus on ASCT2, the present state of knowledge on its roles in tumour biology, and how structural biology is being used to progress the development of inhibitors.

Glycine neurotransmission in the dorsal horn of the spinal cord plays a key role in regulating nociceptive signaling, but in chronic pain states reduced glycine neurotransmission is associated with the development of allodynia and hypersensitivity to painful stimuli. This suggests that restoration of glycine neurotransmission may be therapeutic for the treatment of chronic pain. Glycine transporter 2 inhibitors have been demonstrated to enhance glycine neurotransmission and provide relief from allodynia in rodent models of chronic pain. In recent years, photoswitchable compounds have been developed to provide the possibility of controlling the activity of target proteins using light. In this study we have developed a photoswitchable noncompetitive inhibitor of glycine transporter 2 that has different affinities for the transporter at 365 nm compared to 470 nm light.

The treatment of chronic pain is poorly managed by current analgesics, and there is a need for new classes of drugs. We recently developed a series of bioactive lipids that inhibit the human glycine transporter GlyT2 (SLC6A5) and provide analgesia in animal models of pain. Here, we have used functional analysis of mutant transporters combined with molecular dynamics simulations of lipid-transporter interactions to understand how these bioactive lipids interact with GlyT2. This study identifies a novel extracellular allosteric modulator site formed by a crevice between transmembrane domains 5, 7, and 8, and extracellular loop 4 of GlyT2. Knowledge of this site could be exploited further in the development of drugs to treat pain, and to identify other allosteric modulators of the SLC6 family of transporters., Competing Interests: SM, KW, AS, ZF, SS, TR, RR, MO, RV No competing interests declared, (© 2019, Mostyn et al.)

The Workplace Health Group (WHG) was established in 1998 to conduct research on worker health and safety and organizational effectiveness. This multidisciplinary team includes researchers with backgrounds in psychology, health promotion and behavior, and intervention design, implementation, and evaluation. The article begins with a brief history of the team, its guiding principles, and stages of team formation and development. This section provides examples of the roles, team composition, structure, processes, cognition, leadership, and climate played in the various stages of team development, as well as how they influenced team effectiveness. The WHG formed with functional diversity-variety in knowledge, skills, and abilities-in mind, and the impact of this diversity is discussed throughout the article. Illustrations of how the functional diversity of the WHG has led to real-world impact are provided. The article concludes with some lessons learned and recommendations for creating and sustaining multidisciplinary teams based on the WHG's 20 years of experience and the team science literature. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Inhibitors that target the glycine transporter 2, GlyT2, show promise as analgesics, but may be limited by their toxicity through complete or irreversible binding. Acyl-glycine inhibitors, however, are selective for GlyT2 and have been shown to provide analgesia in animal models of pain with minimal side effects, but are comparatively weak GlyT2 inhibitors. Here, we modify the simple acyl-glycine by synthesizing lipid analogues with a range of amino acid head groups in both l- and d-configurations, to produce nanomolar affinity, selective GlyT2 inhibitors. The potent inhibitor oleoyl-d-lysine (33) is also resistant to degradation in both human and rat plasma and liver microsomes, and is rapidly absorbed following an intraperitoneal injection to rats and readily crosses the blood-brain barrier. We demonstrate that 33 provides greater analgesia at lower doses, and does not possess the severe side effects of the very slowly reversible GlyT2 inhibitor, ORG25543 (2).

Objective: Conduct a cost-effectiveness analysis of the Fuel Your Life (FYL) program dissemination., Methods: Employees were recruited from three workplaces randomly assigned to one of the conditions: telephone coaching, small group coaching, and self-study. Costs were collected prospectively during the efficacy trial. The main outcome measures of interest were weight loss and quality-adjusted life years (QALYs)., Results: The phone condition was most costly ($601 to $589/employee) and the self-study condition was least costly ($145 to $143/employee). For weight loss, delivering FYL through the small group condition was no more effective, yet more expensive, than the self-study delivery. For QALYs, the group delivery of FYL was in an acceptable cost-effectiveness range ($22,400/QALY) relative to self-study (95% confidence interval [CI]: $10,600/QALY-dominated)., Conclusions: Prevention programs require adaptation at the local level and significantly affect the cost, effectiveness, and cost-effectiveness of the program.

Background and Purpose: Inhibitory neurotransmission plays an important role in controlling excitability within nociceptive circuits of the spinal cord dorsal horn. Loss of inhibitory signalling is thought to contribute to the development of pathological pain. Preclinical studies suggest that increasing inhibitory glycinergic signalling is a good therapeutic strategy for treating pain. One approach to increase synaptic glycine is to inhibit the activity of the glycine transporter 2 (GlyT2) on inhibitory nerve terminals. These transporters are involved in regulating glycine concentrations and recycling glycine into presynaptic terminals. Inhibiting activity of GlyT2 increases synaptic glycine, which decreases excitability in nociceptive circuits and provides analgesia in neuropathic and inflammatory pain models., Experimental Approach: We investigated the effects of reversible and irreversible GlyT2 inhibitors on inhibitory glycinergic and NMDA receptor-mediated excitatory neurotransmission in the rat dorsal horn. The effect of these drugs on synaptic signalling was determined using patch-clamp electrophysiology techniques to measure glycine- and NMDA-mediated postsynaptic currents in spinal cord slices in vitro., Key Results: We compared activity of four compounds that increase glycinergic tone with a corresponding increase in evoked glycinergic postsynaptic currents. These compounds did not deplete synaptic glycine release over time. Interestingly, none of these compounds increased glycine-mediated excitatory signalling through NMDA receptors. The results suggest that these compounds preferentially inhibit GlyT2 over G1yT1 with no potentiation of the glycine receptor and without inducing spillover from inhibitory to excitatory synapses., Conclusions and Implications: GlyT2 inhibitors increase inhibitory neurotransmission in the dorsal horn and have potential as pain therapeutics., Linked Articles: This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc., (© 2018 The British Pharmacological Society.)

Purpose: Examine the moderating role of perceived organizational and coworker support on the relationship between job stress and type 2 diabetes risk among employees., Design: A cross-sectional survey was administered to employees at the workplace., Setting: One national retail organization., Participants: Baseline data were obtained from 1595 employees in 21 retail stores., Measures: Self-reported organizational and coworker support to encourage and fulfill job responsibilities and job stress. Diabetes risk was calculated using age, gender, race/ethnicity, blood pressure, physical activity, weight status, and self-reported diagnosed type 2 diabetes., Analysis: Multilevel multiple regression was conducted to test the interaction effect of support on the association between job stress and diabetes risk., Results: Mean age was 37.95 years (±12.03) and body mass index was 26.72 (±4.95). Three percent of participants reported diagnosed diabetes. Organizational support was positively associated with coworker support. Both were negatively associated with job stress. Organizational support, but not coworker support, moderated the relationship of job stress with diabetes risk. Participants with greater perceived organizational support had lower diabetes risk scores compared to those with lower perceived organizational support., Conclusion: Organizational support may be a key factor for workplaces to reduce stress and diabetes risk. Further testing of organizations' supportive role on employee health may be helpful in developing future workplace programs.

Disease management is gaining importance in workplace health promotion given the aging workforce and rising chronic disease prevalence. The Chronic Disease Self-Management Program (CDSMP) is an effective intervention widely offered in diverse community settings; however, adoption remains low in workplace settings. As part of a larger NIH-funded randomized controlled trial, this study examines the effectiveness of a worksite-tailored version of CDSMP (wCDSMP [ n = 72]) relative to CDSMP (&lsquo;Usual Care&rsquo; [ n = 109]) to improve health and work performance among employees with one or more chronic conditions. Multiple-group latent-difference score models with sandwich estimators were fitted to identify changes from baseline to 6-month follow-up. Overall, participants were primarily female (87%), non-Hispanic white (62%), and obese (73%). On average, participants were age 48 (range: 23⁻72) and self-reported 3.25 chronic conditions (range: 1⁻16). The most commonly reported conditions were high cholesterol (45%), high blood pressure (45%), anxiety/emotional/mental health condition (26%), and diabetes (25%). Among wCDSMP participants, significant improvements were observed for physically unhealthy days (u&Delta; = &minus;2.07, p = 0.018), fatigue (u&Delta; = &minus;2.88, p = 0.002), sedentary behavior (u&Delta; = &minus;4.49, p = 0.018), soda/sugar beverage consumption (u&Delta; = &minus;0.78, p = 0.028), and fast food intake (u&Delta; = &minus;0.76, p = 0.009) from baseline to follow-up. Significant improvements in patient⁻provider communication (u&Delta; = 0.46, p = 0.031) and mental work limitations (u&Delta; = &minus;8.89, p = 0.010) were also observed from baseline to follow-up. Relative to Usual Care, wCDSMP participants reported significantly larger improvements in fatigue, physical activity, soda/sugar beverage consumption, and mental work limitations ( p < 0.05). The translation of Usual Care (content and format) has potential to improve health among employees with chronic conditions and increase uptake in workplace settings.

Transporters in the SLC6 family play key roles in regulating neurotransmission and are the targets for a wide range of therapeutics. Important insights into the transport mechanisms and the specificity of drug interactions of SLC6 transporters have been obtained from the crystal structures of a bacterial homologue of the family, LeuT Aa , and more recently the Drosophila dopamine transporter and the human serotonin transporter. However, there is disputed evidence that the bacterial leucine transporter, LeuT Aa , contains two substrate binding sites that work cooperatively in the mechanism of transport, with the binding of a second substrate being required for the release of the substrate from the primary site. An alternate proposal is that there may be low affinity binding sites that serve to direct the flow of substrates to the primary site. We have used a combination of molecular dynamics simulations of substrate interactions with a homology model of GlyT2, together with radiolabeled amino acid uptake assays and electrophysiological analysis of wild-type and mutant transporters, to provide evidence that substrate selectivity of GlyT2 is determined entirely by the primary substrate binding site and, furthermore, if a secondary site exists then it is a low affinity nonselective amino acid binding site.

Cancer cells undergo a shift in metabolism where they become reliant on nutrients such as the amino-acid glutamine. Glutamine enters the cell via the alanine/serine/cysteine transporter 2 (ASCT2) that is upregulated in several cancers to maintain an increased supply of this nutrient and are therefore an attractive target in cancer therapeutic development. ASCT2 belongs to the glutamate transporter (SLC1A) family but is the only transporter in this family able to transport glutamine. The structural basis for glutamine selectivity of ASCT2 is unknown. Here, we identify two amino-acid residues in the substrate-binding site that are responsible for conferring glutamine selectivity. We introduce corresponding mutations into a prokaryotic homologue of ASCT2 and solve four crystal structures, which reveal the structural basis for neutral amino acid and inhibitor binding in this family. This structural model of ASCT2 may provide a basis for future development of selective ASCT2 inhibitors to treat glutamine-dependent cancers.

It has been demonstrated previously that the endogenous compound N-arachidonyl-glycine inhibits the glycine transporter GlyT2, stimulates glycinergic neurotransmission, and provides analgesia in animal models of neuropathic and inflammatory pain. However, it is a relatively weak inhibitor with an IC 50 of 9 μM and is subject to oxidation via cyclooxygenase, limiting its therapeutic value. In this paper we describe the synthesis and testing of a novel series of monounsaturated C18 and C16 acyl-glycine molecules as inhibitors of the glycine transporter GlyT2. We demonstrate that they are up to 28 fold more potent that N-arachidonyl-glycine with no activity at the closely related GlyT1 transporter at concentrations up to 30 μM. This novel class of compounds show considerable promise as a first generation of GlyT2 transport inhibitors.

Crystal structures of the prokaryotic aspartate transporter, Glt Ph , have provided important insights into the mechanism of amino acid transport by Glt Ph and related eukaryotic members of the glutamate transporter family (SLC1A family). Identification of inhibitors of Glt Ph can provide valuable tools for understanding the molecular basis for substrate and inhibitor specificity and selectivity of SLC1A members, but at present, few inhibitors of Glt Ph have been identified. We have screened a collection of commercially available aspartate analogues and identified new transportable and nontransportable Glt Ph inhibitors. We have explored the inhibition profile of Glt Ph by utilizing a thiol modification assay that isolates sided populations of the transporters reconstituted in liposomes to determine if any aspartate analogues display a preference for either the inwardly or outwardly directed binding sites. Here, we have characterized several new inhibitors of Glt Ph and identified three β-carbon-substituted molecules that display a strong preference for the outwardly directed binding site of Glt Ph .

Objective: An accounting of the resources necessary for implementation of efficacious programs is important for economic evaluations and dissemination., Methods: A programmatic costs analysis was conducted prospectively in conjunction with an efficacy trial of Fuel Your Life (FYL), a worksite translation of the Diabetes Prevention Program. FYL was implemented through three different modalities, Group, Phone, and Self-study, using a micro-costing approach from both the employer and societal perspectives., Results: The Phone modality was the most costly at $354.6 per participant, compared with $154.6 and $75.5 for the Group and Self-study modalities, respectively. With the inclusion of participant-related costs, the Phone modality was still more expensive than the Group modality but with a smaller incremental difference ($461.4 vs $368.1)., Conclusions: This level of cost-related detail for a preventive intervention is rare, and our analysis can aid in the transparency of future economic evaluations.

Objective: The aim of this study was to evaluate the effectiveness of the Fuel Your Life program, an adaptation of the Diabetes Prevention Program (DPP), utilizing implementation strategies commonly used in worksite programs-telephone coaching, small group coaching, and self-study., Methods: The primary outcomes of body mass index and weight were examined in a randomized control trial conducted with city/county employees., Results: Although the majority of participants in all three groups lost some weight, the phone group lost significantly more weight (4.9 lb), followed by the small groups (3.4 lb) and the self-study (2.7 lb). Of the total participants, 28.3% of the phone group, 20.6% of the small group, and 15.7% of the self-study group lost 5% or more of their body weight., Conclusions: Fuel Your Life (DPP) can be effectively disseminated using different implementation strategies that are tailored to the workplace.

Neurotransmitter transporters are targets for a wide range of therapeutically useful drugs. This is because they have the capacity to selectively manipulate the dynamics of neurotransmitter concentrations and thereby enhance or diminish signalling through particular brain pathways. High affinity glycine transporters (GlyTs) regulate extracellular concentrations of glycine and provide novel therapeutic targets for neurological disorders., (Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.)

The concentration of glutamate within a glutamatergic synapse is tightly regulated by excitatory amino acid transporters (EAATs). In addition to their primary role in clearing extracellular glutamate, the EAATs also possess a thermodynamically uncoupled Cl(-) conductance. This conductance is activated by the binding of substrate and Na(+), but the direction of Cl(-) flux is independent of the rate or direction of substrate transport; thus, the two processes are thermodynamically uncoupled. A recent molecular dynamics study of the archaeal EAAT homologue GltPh (an aspartate transporter from Pyrococcus horikoshii) identified an aqueous pore at the interface of the transport and trimerization domains, through which anions could permeate, and it was suggested that an arginine residue at the most restricted part of this pathway might play a role in determining anion selectivity. In this study, we mutate this arginine to a histidine in the human glutamate transporter EAAT1 and investigate the role of the protonation state of this residue on anion selectivity and transporter function. Our results demonstrate that a positive charge at this position is crucial for determining anion versus cation selectivity of the uncoupled conductance of EAAT1. In addition, because the nature of this residue influences the turnover rate of EAAT1, we reveal an intrinsic link between the elevator movement of the transport domain and the Cl(-) channel., (© 2016 Cater et al.)

The Na+/Cl- dependent glycine transporters GlyT1 and GlyT2 regulate synaptic glycine concentrations. Glycine transport by GlyT2 is coupled to the co-transport of three Na+ ions, whereas transport by GlyT1 is coupled to the co-transport of only two Na+ ions. These differences in ion-flux coupling determine their respective concentrating capacities and have a direct bearing on their functional roles in synaptic transmission. The crystal structures of the closely related bacterial Na+-dependent leucine transporter, LeuTAa, and the Drosophila dopamine transporter, dDAT, have allowed prediction of two Na+ binding sites in GlyT2, but the physical location of the third Na+ site in GlyT2 is unknown. A bacterial betaine transporter, BetP, has also been crystallized and shows structural similarity to LeuTAa. Although betaine transport by BetP is coupled to the co-transport of two Na+ ions, the first Na+ site is not conserved between BetP and LeuTAa, the so called Na1' site. We hypothesized that the third Na+ binding site (Na3 site) of GlyT2 corresponds to the BetP Na1' binding site. To identify the Na3 binding site of GlyT2, we performed molecular dynamics (MD) simulations. Surprisingly, a Na+ placed at the location consistent with the Na1' site of BetP spontaneously dissociated from its initial location and bound instead to a novel Na3 site. Using a combination of MD simulations of a comparative model of GlyT2 together with an analysis of the functional properties of wild type and mutant GlyTs we have identified an electrostatically favorable novel third Na+ binding site in GlyT2 formed by Trp263 and Met276 in TM3, Ala481 in TM6 and Glu648 in TM10.

This paper examines a loss spiral model (i.e., reciprocal relationships) between work-family conflict and depression, moderated by co-worker support. We expected that the moderation effect due to co-worker support would be evident among those working in isolation (i.e., mining workers) due to a greater level of intragroup attraction and saliency attributable to the proximity effects. We used a two wave panel study and data from a random population sample of Australian employees (n = 2793, [n = 112 mining, n = 2681 non-mining]). Using structural equation modelling we tested the reciprocal three way interaction effects. In line with our theory, co-worker support buffered the reciprocal relationship between WFC and depression, showing a protective effect in both pathways. These moderation effects were found in the mining industry only suggesting a proximity component moderates the social support buffer hypothesis (i.e., a three way interaction effect). The present paper integrates previous theoretical perspectives of stress and support, and provides insight into the changing dynamics of workplace relationships.

Transporters and ion channels are conventionally categorised into distinct classes of membrane proteins. However, some membrane proteins have a split personality and can function as both transporters and ion channels. The excitatory amino acid transporters (EAATs) in particular, function as both glutamate transporters and chloride (Cl(-)) channels. The EAATs couple the transport of glutamate to the co-transport of three Na(+) ions and one H(+) ion into the cell, and the counter-transport of one K(+) ion out of the cell. The EAAT Cl(-) channel is activated by the binding of glutamate and Na(+), but is thermodynamically uncoupled from glutamate transport and involves molecular determinants distinct from those responsible for glutamate transport. Several crystal structures of an EAAT archaeal homologue, GltPh, at different stages of the transport cycle, alongside numerous functional studies and molecular dynamics simulations, have provided extensive insights into the mechanism of substrate transport via these transporters. However, the molecular determinants involved in Cl(-) permeation, and the mechanism by which this channel is activated are not entirely understood. Here we will discuss what is currently known about the molecular determinants involved in EAAT-mediated Cl(-) permeation and the mechanisms that underlie their split personality.

Purpose: To evaluate the effectiveness of FUEL Your Life, a translation of the Diabetes Prevention Program for worksites., Design: A randomized control group design was conducted in five worksites of a large transportation company. Measures were collected pretest, posttest (6 months), and follow-up (12 months)., Setting: Railroad maintenance facilities of Union Pacific Railroad., Subjects: Participants consisted of 362 workers (227 treatment, 135 control)., Intervention: FUEL Your Life was translated from the Diabetes Prevention Program to better fit within the context of the worksite. The primary difference was the use of peer health coaches to provide social support and reinforcement and an occupational nurse to provide lesson content (six sessions of 10 minutes) to participants instead of the lifestyle coaches employed by the Diabetes Prevention Program, resulting in a less structured meeting schedule., Measures: The primary outcomes were weight and body mass index (BMI), with secondary outcomes including eating behaviors, physical activity, and social support., Analysis: Latent growth modeling was used to measure changes in the outcomes over time., Results: Participants in the intervention group maintained weight/BMI (-.1 pounds/-.1 BMI), whereas the control participants gained weight/BMI (+2.6 pounds/+.3 BMI), resulting in a statistically significant difference between groups. Fifty-five percent of intervention participants lost some weight, whereas only 35% of the control group lost weight., Conclusions: FUEL Your Life, a low intensity intervention, was not effective for promoting weight loss, but was effective for helping workers maintain weight over a 12-month period.

Disease management is becoming increasingly important in workplace health promotion given the aging workforce, rising chronic disease prevalence, and needs to maintain a productive and competitive American workforce. Despite the widespread availability of the Chronic Disease Self-Management Program (CDSMP), and its known health-related benefits, program adoption remains low in workplace settings. The primary purpose of this study is to compare personal and delivery characteristics of adults who attended CDSMP in the workplace relative to other settings (e.g., senior centers, healthcare organizations, residential facilities). This study also contrasts characteristics of CDSMP workplace participants to those of the greater United States workforce and provides recommendations for translating CDSMP for use in workplace settings. Data were analyzed from 25,664 adults collected during a national dissemination of CDSMP. Only states and territories that conducted workshops in workplace settings were included in analyses (n = 13 states and Puerto Rico). Chi-squared tests and t-tests were used to compare CDSMP participant characteristics by delivery site type. CDSMP workplace participant characteristics were then compared to reports from the United States Bureau of Labor Statistics. Of the 25,664 CDSMP participants in this study, 1.7% (n = 435) participated in workshops hosted in worksite settings. Compared to CDSMP participants in non-workplace settings, workplace setting participants were significantly younger and had fewer chronic conditions. Differences were also observed based on chronic disease types. On average, CDSMP workshops in workplace settings had smaller class sizes and workplace setting participants attended more workshop sessions. CDSMP participants in workplace settings were substantially older and a larger proportion were female than the general United States workforce. Findings indicate opportunities to translate CDSMP for use in the workplace to reach new target audiences.

The aspartate transporter from Pyrococcus horikoshii (GltPh) is a model for the structure of the SLC1 family of amino acid transporters. Crystal structures of GltPh provide insight into mechanisms of ion coupling and substrate transport; however, structures have been solved in the absence of a lipid bilayer so they provide limited information regarding interactions that occur between the protein and lipids of the membrane. Here, we investigated the effect of the lipid environment on aspartate transport by reconstituting GltPh into liposomes of defined lipid composition where the primary lipid is phosphatidylethanolamine (PE) or its methyl derivatives. We showed that the rate of aspartate transport and the transmembrane orientation of GltPh were influenced by the primary lipid in the liposomes. In PE liposomes, we observed the highest transport rate and showed that 85% of the transporters were orientated right-side out, whereas in trimethyl PE liposomes, 50% of transporters were right-side out, and we observed a 4-fold reduction in transport rate. Differences in orientation can only partially explain the lipid composition effect on transport rate. Crystal structures of GltPh revealed a tyrosine residue (Tyr-33) that we propose interacts with lipid headgroups during the transport cycle. Based on site-directed mutagenesis, we propose that a cation-π interaction between Tyr-33 and the lipid headgroups can influence conformational flexibility of the trimerization domain and thus the rate of transport. These results provide a specific example of how interactions between membrane lipids and membrane-bound proteins can influence function and highlight the importance of the role of the membrane in transporter function., (© 2015 by The American Society for Biochemistry and Molecular Biology, Inc.)

Weight management programs are becoming increasingly common in workplace settings; however, few target middle-aged men. The purpose of this article is to describe the process evaluation of a worksite translation of the Diabetes Prevention Program in a predominantly middle-aged male population. The translated program, FUEL Your Life, was largely self-directed, with support from peer health coaches and occupational health nurses. The RE-AIM (Reach Effectiveness Adoption Implementation Maintenance) framework was used to examine the factors that influenced program implementation using data from an environmental assessment, participant surveys, peer health coach surveys, and occupational health nurse interviews. An overwhelming majority of the employees who enrolled in the study were overweight or obese (92%). Overall, the program was effective for weight maintenance; those with higher levels of participation and engagement had better weight loss outcomes. The peer health coach and family elements of the intervention were underused. The program was successful in reaching the intended population; however, the program had limited success in engaging this population. Not surprisingly, weight loss was a function of participant engagement and participation. Increasing participant engagement and participation is important to the success of weight management interventions translated to the worksite setting. Garnering buy-in and support from management can serve to increase the perceived importance of weight management in worksites. With management support, weight management protocols could be integrated as a component of the mandatory safety and health assessments already in place, fostering promotion of healthy weight in the workforce., (© 2014 Society for Public Health Education.)

The concentration of glutamate within the glutamatergic synapse is tightly regulated by the excitatory amino-acid transporters (EAATs). In addition to their primary role of clearing extracellular glutamate, the EAATs also possess a thermodynamically uncoupled Cl(-) conductance. Several crystal structures of an archaeal EAAT homolog, GltPh, at different stages of the transport cycle have been solved. In a recent structure, an aqueous cavity located at the interface of the transport and trimerization domains has been identified. This cavity is lined by polar residues, several of which have been implicated in Cl(-) permeation. We hypothesize that this cavity opens during the transport cycle to form the Cl(-) channel. Residues lining this cavity in EAAT1, including Ser-366, Leu-369, Phe-373, Arg-388, Pro-392, and Thr-396, were mutated to small hydrophobic residues. Wild-type and mutant transporters were expressed in Xenopus laevis oocytes and two-electrode voltage-clamp electrophysiology, and radiolabeled substrate uptake was used to investigate function. Significant alterations in substrate-activated Cl(-) conductance were observed for several mutant transporters. These alterations support the hypothesis that this aqueous cavity at the interface of the transport and trimerization domains is a partially formed Cl(-) channel, which opens to form a pore through which Cl(-) ions pass. This study enhances our understanding as to how glutamate transporters function as both amino-acid transporters and Cl(-) channels., (Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.)