SYNTHESIS OF N\u3csub\u3eB\u3c/sub\u3e-ARYL-ASPARTAMIDES, N\u3csub\u3ea\u3c/sub\u3e-ARYLAMIDE-ASPARTATES, AND HYDROXY-L-PROLINE DERIVATIVES AS INHIBITORS OF AMINO ACID TRANSPORT FOR EVALUATING THE GLUTAMINE / GLUTAMATE CYCLE

The glutamate / glutamine cycle is most traditionally described as the recycling of L-glutamate and L-glutamine via a concerted effort by a variety of cell membrane spanning amino acid transporters and amino acid converting enzymes, glutaminase and glutamine synthetase. This work details the design and synthesis of amino acid analogs, based off of an L-aspartate or L-proline scaffold, to be evaluated as inhibitors of the amino acid transporters ASCT (subtypes 1 & 2) and the excitatory amino acid transporters EAATs (subtypes 1-3), both involved in the glutamate / glutamine cycle. Furthermore, we have identified a number of potent substrate and nonsubstrate inhibitors of the ASCT and EAAT transporters by electrophysiological and radiolabeled uptake screening. Computational modeling of the synthesized analogs docked into a homology structure suggests a conformational bias that is indeed supported by the pharmacologic activity of our lead compounds. These novel pharmacologic leads will be applied in the design and synthesis of a new generation of inhibitors with greater potency and selectivity towards these transporters of interest

Mechanistic insights into allosteric regulation of the A2A adenosine G protein-coupled receptor by physiological cations.

Cations play key roles in regulating G-protein-coupled receptors (GPCRs), although their mechanisms are poorly understood. Here, 19F NMR is used to delineate the effects of cations on functional states of the adenosine A2A GPCR. While Na+ reinforces an inactive ensemble and a partial-agonist stabilized state, Ca2+ and Mg2+ shift the equilibrium toward active states. Positive allosteric effects of divalent cations are more pronounced with agonist and a G-protein-derived peptide. In cell membranes, divalent cations enhance both the affinity and fraction of the high affinity agonist-bound state. Molecular dynamics simulations suggest high concentrations of divalent cations bridge specific extracellular acidic residues, bringing TM5 and TM6 together at the extracellular surface and allosterically driving open the G-protein-binding cleft as shown by rigidity-transmission allostery theory. An understanding of cation allostery should enable the design of allosteric agents and enhance our understanding of GPCR regulation in the cellular milieu

Digital tools in allergy and respiratory care

Patient care in the allergy and respiratory fields is advancing rapidly, offering the possibility of the inclusion of a variety of digital tools that aim to improve outcomes of care. Impaired access to several health care facilities during the COVID-19 pandemic has considerably increased the appetite and need for the inclusion of e-health tools amongst end-users. Consequently, a multitude of different e-health tools have been launched worldwide with various registration and access options, and with a wide range of offered benefits. From the perspective of both patients and healthcare providers (HCPs), as well as from a legal and device-related perspective, several features are important for the acceptance, effectiveness,and long-term use of e-health tools. Patients and physicians have different needs and expectations of how digital tools might be of help in the care pathway. There is a need for standardization by defining quality assurance criteria.Therefore, the Upper Airway Diseases Committee of the World Allergy Organization (WAO) has taken the initiative to define and propose criteria for quality, appeal, and applicability of e-health tools in the allergy and respiratory care fields from a patient, clinician, and academic perspective with the ultimate aim to improve patient health and outcomes of care

In Situ Reconstitution of the Adenosine A2A Receptor in Spontaneously Formed Synthetic Liposomes

Cell transmembrane receptors play a key role in the detection of environmental stimuli and control of intracellular communication. G protein-coupled receptors constitute the largest transmembrane protein family involved in cell signaling. However, current methods for their functional reconstitution in biomimetic membranes remain both challenging and limited in scope. Herein, we describe the spontaneous reconstitution of adenosine A2A receptor (A2AR) during the de novo formation of synthetic liposomes via native chemical ligation. The approach takes advantage of a nonenzymatic and chemoselective method to rapidly generate A2AR embedded phospholiposomes from receptor solubilized in n-dodecyl-β-d-maltoside analogs. In situ lipid synthesis for protein reconstitution technology proceeds in the absence of dialysis and/or detergent absorbents, and A2AR assimilation into synthetic liposomes can be visualized by microscopy and probed by radio-ligand binding

Mechanistic insights into allosteric regulation of the A2A adenosine G protein-coupled receptor by physiological cations.

Cations play key roles in regulating G-protein-coupled receptors (GPCRs), although their mechanisms are poorly understood. Here, 19F NMR is used to delineate the effects of cations on functional states of the adenosine A2A GPCR. While Na+ reinforces an inactive ensemble and a partial-agonist stabilized state, Ca2+ and Mg2+ shift the equilibrium toward active states. Positive allosteric effects of divalent cations are more pronounced with agonist and a G-protein-derived peptide. In cell membranes, divalent cations enhance both the affinity and fraction of the high affinity agonist-bound state. Molecular dynamics simulations suggest high concentrations of divalent cations bridge specific extracellular acidic residues, bringing TM5 and TM6 together at the extracellular surface and allosterically driving open the G-protein-binding cleft as shown by rigidity-transmission allostery theory. An understanding of cation allostery should enable the design of allosteric agents and enhance our understanding of GPCR regulation in the cellular milieu

In Situ Reconstitution of the Adenosine A_2A Receptor in Spontaneously Formed Synthetic Liposomes

Cell transmembrane receptors play a key role in the detection of environmental stimuli and control of intracellular communication. G protein-coupled receptors constitute the largest transmembrane protein family involved in cell signaling. However, current methods for their functional reconstitution in biomimetic membranes remain both challenging and limited in scope. Herein, we describe the spontaneous reconstitution of adenosine A_2A receptor (A_2AR) during the de novo formation of synthetic liposomes via native chemical ligation. The approach takes advantage of a nonenzymatic and chemoselective method to rapidly generate A_2AR embedded phospholiposomes from receptor solubilized in <i>n</i>-dodecyl-β-d-maltoside analogs. In situ lipid synthesis for protein reconstitution technology proceeds in the absence of dialysis and/or detergent absorbents, and A_2AR assimilation into synthetic liposomes can be visualized by microscopy and probed by radio-ligand binding

Digital tools in allergy and respiratory care

Patient care in the allergy and respiratory fields is advancing rapidly, offering the possibility of the inclusion of a variety of digital tools that aim to improve outcomes of care. Impaired access to several health care facilities during the COVID-19 pandemic has considerably increased the appetite and need for the inclusion of e-health tools amongst end-users. Consequently, a multitude of different e-health tools have been launched worldwide with various registration and access options, and with a wide range of offered benefits. From the perspective of both patients and healthcare providers (HCPs), as well as from a legal and device-related perspective, several features are important for the acceptance, effectiveness,and long-term use of e-health tools. Patients and physicians have different needs and expectations of how digital tools might be of help in the care pathway. There is a need for standardization by defining quality assurance criteria.Therefore, the Upper Airway Diseases Committee of the World Allergy Organization (WAO) has taken the initiative to define and propose criteria for quality, appeal, and applicability of e-health tools in the allergy and respiratory care fields from a patient, clinician, and academic perspective with the ultimate aim to improve patient health and outcomes of care.</p

Eigenstate Thermalization, Random Matrix Theory and Behemoths

The eigenstate thermalization hypothesis (ETH) is one of the cornerstones in our understanding of quantum statistical mechanics. The extent to which ETH holds for nonlocal operators is an open question that we partially address in this paper. We report on the construction of highly nonlocal operators, Behemoths, that are building blocks for various kinds of local and non-local operators. The Behemoths have a singular distribution and width w∼D−1 (D being the Hilbert space dimension). From them, one may construct local operators with the ordinary Gaussian distribution and w∼D−1/2 in agreement with ETH. Extrapolation to even larger widths predicts sub-ETH behavior of typical nonlocal operators with w∼D−δ, 0<δ<1/2. This operator construction is based on a deep analogy with random matrix theory and shows striking agreement with numerical simulations of non-integrable many-body systems

Digital tools in allergy and respiratory care

Patient care in the allergy and respiratory fields is advancing rapidly, offering the possibility of the inclusion of a variety of digital tools that aim to improve outcomes of care. Impaired access to several health care facilities during the COVID-19 pandemic has considerably increased the appetite and need for the inclusion of e-health tools amongst end-users. Consequently, a multitude of different e-health tools have been launched worldwide with various registration and access options, and with a wide range of offered benefits. From the perspective of both patients and healthcare providers (HCPs), as well as from a legal and device-related perspective, several features are important for the acceptance, effectiveness,and long-term use of e-health tools. Patients and physicians have different needs and expectations of how digital tools might be of help in the care pathway. There is a need for standardization by defining quality assurance criteria. Therefore, the Upper Airway Diseases Committee of the World Allergy Organization (WAO) has taken the initiative to define and propose criteria for quality, appeal, and applicability of e-health tools in the allergy and respiratory care fields from a patient, clinician, and academic perspective with the ultimate aim to improve patient health and outcomes of care