Discovery and multimerization of cross-reactive single-domain antibodies against SARS-like viruses to enhance potency and address emerging SARS-CoV-2 variants.

Coronaviruses have been the causative agent of three epidemics and pandemics in the past two decades, including the ongoing COVID-19 pandemic. A broadly-neutralizing coronavirus therapeutic is desirable not only to prevent and treat COVID-19, but also to provide protection for high-risk populations against future emergent coronaviruses. As all coronaviruses use spike proteins on the viral surface to enter the host cells, and these spike proteins share sequence and structural homology, we set out to discover cross-reactive biologic agents targeting the spike protein to block viral entry.

Hexamerization of Anti-SARS CoV IgG1 Antibodies Improves Neutralization Capacity.

The SARS-CoV-2 pandemic and particularly the emerging variants have deepened the need for widely available therapeutic options. We have demonstrated that hexamer-enhancing mutations in the Fc region of anti-SARS-CoV IgG antibodies lead to a noticeable improvement in IC in both pseudo and live virus neutralization assay compared to parental molecules. We also show that hexamer-enhancing mutants improve C1q binding to target surface.

Antihypertensive effect of etamicastat in dopamine D2 receptor-deficient mice.

Abnormalities of the DR gene (DRD2) play a role in the pathogenesis of human essential hypertension; variants of the DRD2 have been reported to be associated with hypertension. Disruption of Drd2 (D) in mice increases blood pressure. The hypertension of D mice has been related, in part, to increased sympathetic activity, renal oxidative stress, and renal endothelin B receptor (ETBR) expression.

Chemical Imaging by Dissolution Analysis: Localized Kinetics of Dissolution Behavior to Provide Two-Dimensional Chemical Mapping and Tomographic Imaging on a Nanoscale.

A new approach to achieving chemical mapping on a nanoscale is described that can provide 2D and tomographic images of surface and near-surface structure. The method comprises dissolving material from the surface of the sample by applying a series of aliquots of solvent, then analyzing their contents after removing them; in between exposures, the surface is imaged with atomic force microscopy. This technique relies on being able to compensate for any drift between images by use of software.

Efficacy of Hybrid Tetrahydrobenzo[d]thiazole Based Aryl Piperazines D-264 and D-301 at D₂ and D₃ Receptors.

In elucidating the role of pharmacodynamic efficacy at D3 receptors in therapeutic effectiveness of dopamine receptor agonists, the influence of study system must be understood. Here two compounds with D3 over D2 selectivity developed in our earlier work, D-264 and D-301, are compared in dopamine receptor-mediated G-protein activation in striatal regions of wild-type and D2 receptor knockout mice and in CHO cells expressing D2 or D3 receptors. In caudate-putamen of D2 knockout mice, D-301 was ~3-fold more efficacious than D-264 in activating G-proteins as assessed by [(35)S]GTPγS binding; in nucleus accumbens, D-301 stimulated G-protein activation whereas D-264 did not.

"TAARgeting Addiction"--The Alamo Bears Witness to Another Revolution: An Overview of the Plenary Symposium of the 2015 Behavior, Biology and Chemistry Conference.

Background: In keeping with the free-thinking tradition San Antonians are known for, the Scientific Program Committee of the Behavior, Biology and Chemistry: Translational Research in Addiction Conference chose trace amine-associated receptor 1 (TAAR1) as the focus of the plenary symposium for its 7th annual meeting held at the University of Texas Health Science Center at San Antonio on March 14 and 15, 2015. The timing of the meeting's plenary session on TAAR1 coincided with the Ides of March, an apt concurrence given the long association of this date with the overthrow of the status quo. And whether aware of the coincidence or not, those in attendance witnessed the plunging of the metaphorical dagger into the heart of the dopamine (DA) transporter (DAT)-centric view of psychostimulant action.

Trace Amine-Associated Receptor 1 Localization at the Apical Plasma Membrane Domain of Fisher Rat Thyroid Epithelial Cells Is Confined to Cilia.

Background: The trace amine-associated receptor 1 (Taar1) is one member of the Taar family of G-protein-coupled receptors (GPCR) accepting various biogenic amines as ligands. It has been proposed that Taar1 mediates rapid, membrane-initiated effects of thyronamines, the endogenous decarboxylated and deiodinated relatives of the classical thyroid hormones T4 and T3.

Objectives: Although the physiological actions of thyronamines in general and 3-iodothyronamine (T1AM) in particular are incompletely understood, studies published to date suggest that synthetic T1AM-activated Taar1 signaling antagonizes thyromimetic effects exerted by T3.

Dopamine D₂-Like Receptors and Behavioral Economics of Food Reinforcement.

Previous studies suggest dopamine (DA) D2-like receptor involvement in the reinforcing effects of food. To determine contributions of the three D2-like receptor subtypes, knockout (KO) mice completely lacking DA D2, D3, or D4 receptors (D2R, D3R, or D4R KO mice) and their wild-type (WT) littermates were exposed to a series of fixed-ratio (FR) food-reinforcement schedules in two contexts: an open economy with additional food provided outside the experimental setting and a closed economy with all food earned within the experimental setting. A behavioral economic model was used to quantify reinforcer effectiveness with food pellets obtained as a function of price (FR schedule value) plotted to assess elasticity of demand.

Regulation of ethanol intake under chronic mild stress: roles of dopamine receptors and transporters.

Studies have shown that exposure to chronic mild stress decreases ethanol intake and preference in dopamine D2 receptor wild-type mice (Drd2 (+/+)), while it increases intake in heterozygous (Drd2 (+/-)) and knockout (Drd2 (-/-)) mice. Dopaminergic neurotransmission in the basal forebrain plays a major role in the reinforcing actions of ethanol as well as in brain responses to stress. In order to identify neurochemical changes associated with the regulation of ethanol intake, we used in vitro receptor autoradiography to measure the levels and distribution of dopamine D1 and D2 receptors and dopamine transporters (DAT).

The effect of dopamine D4 receptor density on novelty seeking, activity, social interaction, and alcohol binge drinking in adult mice.

The dopamine D4 receptor has been postulated to play a role in the pathophysiology of alcoholism. This study examined how varying levels of D4 expression and their associated behaviors in male and female mice correlate with future alcohol intake. We hypothesized that: (1) mice with low (Drd4(+/-) ) or deficient (Drd4(-/-) ) in D4 receptors would show enhanced ethanol consumption compared with control mice (Drd4(+/+) ), and (2) a specific phenotype in these mice is associated with future vulnerability for alcohol consumption.

Ractopamine, a livestock feed additive, is a full agonist at trace amine-associated receptor 1.

Ractopamine (RAC) is fed to an estimated 80% of all beef, swine, and turkey raised in the United States. It promotes muscle mass development, limits fat deposition, and reduces feed consumption. However, it has several undesirable behavioral side effects in livestock, especially pigs, including restlessness, agitation, excessive oral-facial movements, and aggressive behavior.

Choice for response alternatives differing in reinforcement frequency in dopamine D2 receptor mutant and Swiss-Webster mice.

Rationale: A previous study showed that dopamine (DA) D2 receptors (D2Rs) are involved in the reinforcing effectiveness of food, but the specific involvement of DA D2Rs in choice among food reinforcers remains unclear.

Objectives: The current study used genetic and pharmacological approaches to assess the role of D2Rs in choice among food-reinforcement frequencies using the generalized matching law (GML), which specifies that logged response and time allocation ratios vary linearly with logged reinforcer ratios.

Methods: Congenic D2R knockout (KO) and wild-type (WT) mice were exposed to concurrent variable-interval schedules of reinforcement with scheduled relative-reinforcement rates from 4:1 to 1:4.

Dopamine D4 receptors in psychostimulant addiction.

Since the cloning of the D4 receptor in the 1990s, interest has been building in the role of this receptor in drug addiction, given the importance of dopamine in addiction. Like the D3 receptor, the D4 receptor has limited distribution within the brain, suggesting it may have a unique role in drug abuse. However, compared to the D3 receptor, few studies have evaluated the importance of the D4 receptor.

Exploring the determinants of trace amine-associated receptor 1's functional selectivity for the stereoisomers of amphetamine and methamphetamine.

Amphetamines are widely abused drugs that interfere with dopamine transport and storage. Recently, however, another mechanism of action was identified: stereoselective activation of the GαS protein-coupled trace amine-associated receptor 1 (TAAR1). To identify structural determinants of this stereoselectivity, we functionally evaluated six mutant receptors in vitro and then used homology modeling and dynamic simulation to predict drug affinities.

Pharmacological characterization of a dopamine transporter ligand that functions as a cocaine antagonist.

An N-butyl analog of benztropine, JHW007 [N-(n-butyl)-3α-[bis(4'-fluorophenyl)methoxy]-tropane], binds to dopamine transporters (DAT) but has reduced cocaine-like behavioral effects and antagonizes various effects of cocaine. The present study further examined mechanisms underlying these effects. Cocaine dose-dependently increased locomotion, whereas JHW007 was minimally effective but increased activity 24 hours after injection.

High-level expression of a full-length Eph receptor.

Eph receptors are the largest family of Receptor Tyrosine Kinases containing a single membrane-spanning segment. They are involved in a various developmental and cell-cell communication events. Although there is extensive structural information available on both the extra- and intracellular regions of Eph's in isolation, no structures are available for the entire receptor.

Normalizing dopamine D2 receptor-mediated responses in D2 null mutant mice by virus-mediated receptor restoration: comparing D2L and D2S.

D2 receptor null mutant (Drd2(-/-)) mice have altered responses to the rewarding and locomotor effects of psychostimulant drugs, which is evidence of a necessary role for D2 receptors in these behaviors. Furthermore, work with mice that constitutively express only the D2 receptor short form (D2S), as a result of genetic deletion of the long form (D2L), provides the basis for a current model in which D2L is thought to be the postsynaptic D2 receptor on medium spiny neurons in the basal forebrain, and D2S the autoreceptor that regulates the activity of dopamine neurons and dopamine synthesis and release. Because constitutive genetic deletion of the D2 or D2L receptor may cause compensatory changes that influence functional outcomes, our approach is to identify aspects of the abnormal phenotype of a Drd2(-/-) mouse that can be normalized by virus-mediated D2 receptor expression.

DRD4 genotype predicts longevity in mouse and human.

Longevity is influenced by genetic and environmental factors. The brain's dopamine system may be particularly relevant, since it modulates traits (e.g.

Dopamine D4 receptor deficiency in mice alters behavioral responses to anxiogenic stimuli and the psychostimulant methylphenidate.

An allele of the human dopamine D4 receptor (D4R) gene (DRD4), containing seven tandem repeats of a 48-base nucleotide sequence (DRD4.7), has been reproducibly found in novelty seekers, substance abusers, and individuals with attention-deficit hyperactivity disorder. One hypothesis predicts the resultant protein product of the DRD4.

Chronic mild stress increases alcohol intake in mice with low dopamine D2 receptor levels.

Alcohol use disorders emerge from a complex interaction between environmental and genetic factors. Stress and dopamine D2 receptor levels (DRD2) have been shown to play a central role in alcoholism. To better understand the interactions between DRD2 and stress in ethanol intake behavior, we subjected Drd2 wild-type (+/+), heterozygous (+/-), and knockout (-/-) mice to 4 weeks of chronic mild stress (CMS) and to an ethanol two-bottle choice during CMS weeks 2-4.

Deficient dopamine D2 receptor function causes renal inflammation independently of high blood pressure.

Renal dopamine receptors participate in the regulation of blood pressure. Genetic factors, including polymorphisms of the dopamine D(2) receptor gene (DRD2) are associated with essential hypertension, but the mechanisms of their contribution are incompletely understood. Mice lacking Drd2 (D(2)-/-) have elevated blood pressure, increased renal expression of inflammatory factors, and renal injury.

Paraoxonase 2 decreases renal reactive oxygen species production, lowers blood pressure, and mediates dopamine D2 receptor-induced inhibition of NADPH oxidase.

The dopamine D(2) receptor (D(2)R) regulates renal reactive oxygen species (ROS) production, and impaired D(2)R function results in ROS-dependent hypertension. Paraoxonase 2 (PON2), which belongs to the paraoxonase gene family, is expressed in various tissues, acting to protect against cellular oxidative stress. We hypothesized that PON2 may be involved in preventing excessive renal ROS production and thus may contribute to maintenance of normal blood pressure.