bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increasing upstream chromatin long‐range interactions may favor induction of circular RNAs in lysoPC‐activated human aortic endothelial cells
Authors: Li Angus , Sun Yu , Drummer Charles , Yu Daohai , Zhou Yan , Li Xinyuan , Johnson Candice , Yu Caijia , Yang William , Jiang Xiaohua , Hu Wenhui , Wang Hong , Yang Xiaofeng 
Published: June 2021

Circular RNAs (circRNAs) are classified as non‐coding RNA that form covalently closed continuous loops and act as gene regulators in physiological and disease conditions. We hypothesize that proatherogenic lipid lysophosphatidylcholine (LPC) induce a set of circRNAs in human aortic endothelial cell (HAEC) activation. We performed circRNA analysis by searching our RNA‐Seq data from LPC‐activated HAECs and found: 1) LPC induce significant modulation of 77 newly characterized cirRNAs, among which 47 circRNAs (61%) are upregulated; 2) 34 (72%) out of 47 upregulated circRNAs are upregulated when the corresponding mRNAs are downregulated, suggesting that the majority of circRNAs are upregulated presumably via LPC‐induced “abnormal splicing” when the canonical splicing for generation of corresponding mRNAs is suppressed; 3) Upregulation of 47 circRNAs is associated with LPC‐upregulated cholesterol synthesis‐SREBP2 pathway and LPC‐downregulated TGF‐β pathway; 4) increased upstream chromatin long‐range interaction sites to circRNA related genes favor circRNA generation over canonical splicing for mRNAs, suggesting that shifting chromatin long‐range interaction sites from downstream to upstream promotes induction of a list of circular RNAs in lysoPC‐activated human aortic endothelial cells; 5) six significantly changed circRNAs may have sponge functions for miRNAs; and 6) 74% significantly changed circRNAs contain open reading frames, suggesting that short proteins may interfere the protein interaction‐based signaling. Our finding have demonstrated for the first time that a new set of LPC‐induced circRNAs may contribute to proatherogenic LPC‐induced HAEC activation. These novel insights may lead to identification of new therapeutic targets for treating metabolic cardiovascular diseases, inflammations and cancers.Support or Funding InformationThis work was supported by NIH grants to Drs. XF Yang and H Wang.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Active Learning in a Pharmacology Classroom
Authors: Ayanniyi Rashidat Oluwafunke , Olumoh‐Abdul Hidayah Ayodeji 
Published: June 2021

Pharmacology teaching in Nigeria is extremely teacher‐centered and does not meet the educational needs of Pharmacy students. Despite the numerous advantages of active learning, Pharmacy schools in Nigeria are yet to adopt this teaching method.This action research was carried out to introduce and determine the effectiveness of active learning in a pharmacology classroom. Twenty‐four Pharmacy students in their third year participated in the study. Randomized control‐group pre‐test post‐test design was used. A pre‐test was administered to the control and treatment groups. Traditional lecture method was employed in teaching twelve students (control group) while three active learning strategies; Think‐pair‐share, Student presentation and Socratic questioning was used in teaching a cardiovascular module to twelve students (treatment group). A Post‐test was given to both groups after four weeks of instruction. We administered a structured questionnaire to obtain information on students' perception of active learning strategies. A higher mean score was obtained from the post‐test of students taught with active learning strategies. Majority of the respondents agreed active learning enhanced team work, increased their knowledge and confidence. Inadequate pre‐class preparation by the students was a major barrier encountered with use of active learning strategies and more time will be required to depart from passive to active learning. In conclusion, students were involved in the learning process and effective instruction was achieved. These findings will be of value to educators who plan to adopt active learning strategies in small classrooms.Support or Funding InformationNo funding.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Therapeutic Potential of G‐protein‐Biased Kratom‐Derived and Synthetic Carfentanil‐Amide Opioids for Alcohol Use Disorder
Authors: Gutridge Anna M , Robins Meridith T , Cassell Robert J , Uprety Rajendra , Mores Kendall L , Ko Mee Jung , Pasternak Gavril W , Majumdar Susruta , van Rijn Richard M 
Published: June 2021

Mitragyna speciosa, also known as kratom, is a plant containing opioidergic alkaloids and is currently being used to self‐medicate chronic pain, opioid dependence, and is also used as a heroin substitute. Kratom, though unscheduled, may be less dangerous when compared to prescription opioids due to the preferential interaction of kratom alkaloids with G‐proteins instead of beta‐arrestin proteins. We hypothesized that kratom alkaloids and synthetic opioids with similar biased pharmacology can be used to treat alcohol use disorder. We completed in vitro pharmacological characterization for two kratom strain extracts, four kratom alkaloids (mitragynine, 7‐hydroxymitragynine, paynantheine, and speciogynine), and a series of synthetic carefentanil‐amide opioids by determining their ability to interact selectively with G‐proteins instead of beta‐arrestin at the mu, delta and kappa opioid receptors. In addition, in C57BL/6 mice we assessed if kratom (alkaloids) and opioids were capable of reducing alcohol use and determined if the alkaloids had rewarding properties. We found that kratom alkaloids are strongly biased towards the G‐protein pathway at all three opioid receptors. More specifically, we found the delta opioid receptor plays an important role in the mechanism of action as interpreted from reduced efficacy in knockout mice. MP102, one of the synthesized carfentanilamide opioids, displayed a pharmacological profile similar to the kratom alkaloids but with preference for delta opioid receptors, and also reduced alcohol intake and likewise produced less significant place preference than morphine. Our findings demonstrate that kratom use can decrease alcohol use, but its use still carries substantial risk. The development of further delta‐opioid‐selective synthetic opioids may provide an avenue for alcohol use treatment that does not produce strong rewards.Support or Funding InformationRMvR support: NIH grants AA025368, AA026949, AA026675, DA045897, a NARSAD young investigator award from The Brain and Behavior Research Foundation, the Purdue Institute for Drug Discovery and the Dept. of Med.Chem. and Molecular Pharmacology. SM support: NIH grants DA045884, DA046487, AA026949 and W81XWH‐17‐1‐0256 & start‐up funds from the Center for Clinical Pharmacology in St. Louis. Funded in part through NIH/NCI Cancer Center Support Grant P30. CA008748.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Decline of Glutamate‐Stimulated Norepinephrine Release in Aging Rat Brain
Authors: Dezfuli Ghazaul , Martin Lukas , Olson Thao , Kellar Kenneth J. 
Published: June 2021

Unravelling and understanding the molecular and neurochemical changes of the aging brain is key to early intervention strategies. Glutamate (Glu) neurotransmission, the major excitatory neurotransmitter in the brain, is mechanistically involved in memory, learning performance, and other aspects of cognition. Moreover, as the brain ages, the glutamatergic signaling system mediated through brain N‐methyl‐D‐aspartate (NMDA) receptors becomes hypofunctional, and this decline may be associated with cognitive dysfunction in normal aging and in disease states. We have developed an in vitro assay that measures Glu‐stimulated release of neurotransmitters in rat brain slices. Using this assay, we compared changes in Glu‐stimulated release of [3H]‐norepinephrine (NE) from the cerebral cortex and hippocampus in young (2–3 months old) versus old (21–23 months old) Fischer F344 rats. Our findings demonstrate that that there is a pronounced deficit (approximately 30–40%) of Glu‐stimulated [3H]‐NE release in the aged rat brain in comparison to younger controls. In the same tissues, potassium (K+) stimulated‐NE release is similar in brains from young and old rats, suggesting that the age‐related decline in in Glu‐stimulated NE release is related to a change in NMDA receptors. Notably, the deficit in Glu‐stimulated [3H]‐NE release in both brain regions was completely rescued by the addition of 1 uM d‐amphetamine sulfate to the tissue slices. Overall, these findings reveal an important deficit in NE release in the aging brain, which may have important implications for cognitive dysfunction in aging. Moreover, this deficit can be reversed with amphetamine and possibly with similar drugs. These studies have clear clinical implications for the use of CNS stimulants as a therapeutic intervention for early cognitive impairment.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Treatment with polyamine oxidase inhibitor reduced neurodegeneration and improved retinal function in diabetic mice
Authors: Liu Fang , Saul Alan B , Xu Zhimin , Palani Chithra D , Shosha Esraa , Caldwell Ruth B , Narayanan S. Priya 
Published: June 2021

PurposeDeregulation of polyamine metabolism has been implicated in various neurodegenerative disease and injury conditions. Studies from our laboratory have demonstrated that polyamine oxidation is a critical mediator of both neuronal and vascular injury in a mouse model of retinopathy of prematurity (Narayanan et al 2014; Patel et al 2016). The current study was undertaken to investigate the role of the polyamine oxidase spermine oxidase (SMO) in mediating neuronal damage and dysfunction in the diabetic retina.MethodsMice (8 weeks old, C57BL6J) were made diabetic by injection of streptozotocin (STZ, 65 mg/kg, pH 4.5, i.p.) and compared to age‐matched controls after 4 to 15 weeks of diabetes. Following the onset of hyperglycemia, mice were treated with either vehicle (normal saline) or SMO inhibitor, MDL 72527 (20 mg/kg of body weight, in saline, intra‐peritoneal, 3 times/week). Retinal neuronal function in living mice was determined by electroretinography (ERG). Retinal structure in the same mice was analyzed by Spectral Domain‐Optical Coherence Tomography (SD‐OCT). Following ERG and SD‐OCT analyses, mice were humanely euthanized, and retinas were collected and processed for immunofluorescence and western blot analyses.ResultsWestern blot analysis showed that expression of SMO was increased in the diabetic retinas compared to controls. Inner retinal function studied by dark‐adapted electroretinography showed that the positive (pSTR) and negative (nSTR) scotopic threshold responses (measured at 110 ms and 200 ms), were significantly reduced (p<0.01, N=5–12) in the diabetic (4–12 weeks) mice as compared with the controls. The pSTR, but not the nSTR amplitudes were greatly improved in the MDL‐treated diabetic mice (p<0.05, N=5–10). The amplitude at 110 ms was dominated by the b‐wave at higher intensities and was significantly stronger in the MDL72527‐treated mice than in the vehicle‐treated diabetic mice. SD‐OCT analysis demonstrated a significant thinning of retina in the diabetic mice (p<0.01, N=5–12), which was improved in the MDL‐treated group. These data demonstrate a partial rescue of inner retinal function and retinal structure by SMO inhibition in the diabetic retina. Studies on the impact of MDL72527 treatment on neuronal survival are currently in progress.ConclusionOur results show the specific involvement of Spermine Oxidase in mediating neuronal injury in the diabetic retina and demonstrate its potential as a therapeutic target for mitigating neuronal injury in diabetic retinopathy.Support or Funding InformationThese studies supported by the National Eye Institute (1R01EY028569 to S.P.N) and Augusta University Culver Vision Discovery institute pilot grant to S.P.N.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Ca2+ allostery in PTH‐receptor signaling
Authors: White Alex , Sutkeviciute Ieva , Jean‐Alphonse Frederic , Xiao Kunhong , Vilardaga Jean‐Pierre 
Published: June 2021

The parathyroid hormone (PTH) type 1 receptor (PTHR) serves as the cognate receptor for two endogenous ligands, PTH and its related peptide (PTHrP). Binding of PTHrP to the PTHR results in only transient cAMP production that is limited to the plasma membrane, while PTH induces sustained cAMP responses derived from endosomes following internalization of the ligand‐receptor complex. The underlying mechanism and regulation of these kinetically‐distinct signaling events are poorly understood. Here we show that extracellular Ca2+ acts as a positive allosteric modulator of the PTHR that promotes sustained cAMP production. Equilibrium and kinetic analysis of ligand binding and receptor activation revealed that extracellular Ca2+ increases the residence time of ligands on the receptor, consequently increasing the duration of receptor activation and cAMP production. Additionally, we found that this sensitivity to Ca2+ is lost for the PTH mutant R25C, identified as a cause of hypocalcemia in human patients. Using mass spectrometry (MS) approaches, we identified acidic clusters in the first extracellular loop of PTHR that serve a critical role in mediating Ca2+ allostery and sustained cAMP signaling. These findings provide insights toward understanding the determinants of PTHR‐mediated signaling events and how these processes are regulated.Support or Funding InformationNothing to Disclose: AW, IS, FGJ, KX, JPVSources of Research Support: the National Institute of Diabetes and Digestive and Kidney Disease (NIDDK) and the National Institute of General Medical Sciences (NIGMS) of the US National Institutes of Health (NIH) under grant Awards Number R01‐DK102495, R01‐DK111427, and R01‐DK116780 (to J.P.V.), and T32‐GM008424 (to A.D.W.).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Negative Allosteric Modulation of Arrestin Recruitment to the β2‐Adrenergic Receptor
Authors: Ippolito Michael , Hopfinger Nathan , Nayak Ajay P. , Sakkal Leon A. , Rajkowski Kyle Z. , Liu Xiangyu , Kobilka Brian K. , Penn Raymond B. , Armen Roger S. , Scott Charles P. , Benovic Jeffrey L. 
Published: June 2021

The β2‐adrenergic receptor (β2AR) is a Gs‐coupled receptor that promotes an agonist‐dependent cyclic AMP (cAMP)‐mediated reversal of bronchoconstriction that is therapeutic for airway diseases like asthma. Long‐term use of β‐agonists is associated with arrestin mediated desensitization of response to treatment. Gs‐biased signaling through the β2AR would have clinical utility in promoting airway relaxation while avoiding desensitization of response to β‐agonists. Using bioluminescence resonance energy transfer (BRET) for arrestin recruitment, cAMP ELISAs, radioligand assays, mutagenesis, X‐ray crystallography, and ex vivo airway tissue models, we characterized compounds that inhibit arrestin recruitment to the β2AR without inhibiting cAMP production in the presence of β‐agonists. Our data reveal a druggable allosteric site in the extracellular vestibule of the β2AR that can be targeted to modulate arrestin recruitment to the receptor without affecting Gs coupling. Here we characterize a small molecule that targets this site to promote β2AR specific, negative allosteric modulation of arrestin recruitment that is protective against agonist‐induced desensitization in cells and airway tissue.Support or Funding InformationResearch funded by NIH training grant GM100836, P01 HL114471, and F31 HL139104.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Comparative Pharmacology and Structure–Activity Relationships of D1 Dopamine Receptor Positive Allosteric Modulators
Authors: Luderman Kathryn D. , Free R. Benjamin , Aubé Jeffrey , Frankowski Kevin J. , Sibley David R. 
Published: June 2021

The D1 dopamine receptor (D1R) is a key component of regulating dopaminergic signaling and, as such, is associated with many important neurological processes and diseases. It is an attractive target to treat a wide range of neuropsychiatric disorders, such as Parkinson's disease and the cognitive decline associated with schizophrenia and Alzheimer's disease. Positive allosteric modulators (PAMs) of the D1R have emerged as a drug development strategy, as D1R orthosteric agonists have clinical liabilities curtailing their use. We discovered two D1R PAMs via a high‐throughput screen, MLS1082 and MLS6585. The two PAMs act similarly, potentiating agonist‐stimulated G‐protein and β‐arrestin‐mediated signaling and increasing dopamine's affinity for the D1R. Neither compound has any inherent agonist activity in the absence of dopamine. MLS1082 and MLS6585 are structurally distinct chemical series and we have found they act at two separate binding sites. MLS1082 shares a similar binding site with two known D1 PAMs, Compound B and DETQ, which involves the R130 amino acid in the second intracellular loop of the D1R. MLS6585 displays additive activity with MLS1082, Compound B, and DETQ and its activity is not affected by a R130Q point mutation, strongly suggesting that MLS6585 acts at a separate binding site than these other D1R PAMs. Though D1R PAMs have been described by our group and others, the pharmacology and structure–activity relationships (SAR) underlying D1R allosteric modulation is not well understood. We used several analog sets of both MLS1082 and MLS6585 in order to begin addressing these questions as well as to improve on the D1R PAM activity of the parent compounds. Many of the analogs of both MLS1082 and MLS6585 retained PAM activity, validating these drug scaffolds as D1R modulators. The analogs of one series displayed additive activity with the opposite series, suggesting that the analogs are binding to similar sites as their parent compounds. The largest improvement on the parent compounds came via better selectivity for the D1R over the closely related D5 dopamine receptor. This has important implications for understanding the homology of allosteric sites between related receptor types. A small number of seemingly inactive analogs appear to act as silent allosteric modulators (SAMs), in that they blocked the activity of the parent PAM compound, presumably by competing for the same binding site. Further analog studies are underway to better understand the chemical SAR needed for D1R allosteric modulation as well as the differences between the two D1R PAM binding sites.Support or Funding InformationFunded by NINDS Intramural Research Program and Eshelman Institute for InnovationThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
A Family of Photoswitchable Metabotropic Glutamate Receptors for High‐Efficiency Optical Interrogation of Specific Receptor Populations in vivo
Authors: Gutzeit Vanessa , Ruiz Amanda Acosta , Broichhagen Johannes , Levitz Joshua 
Published: June 2021

G protein‐coupled receptors (GPCRs) form a large family of membrane bound receptors that initiate intracellular responses which control cellular signaling cascades to contribute to a wide range of biological functions. The metabotropic glutamate receptors (mGluRs) consist of an eight‐member family of class C GPCRs that respond to the excitatory neurotransmitter glutamate and serve as promising pharmacological targets for a range of neurological and psychiatric disorders. mGluRs are localized in a variety of cell types throughout the central nervous system where they can modulate neuronal activity in both normal and disease‐related states. Despite the prevalence of these receptors, the underlying molecular, synaptic and circuit mechanisms of mGluR‐mediated neuromodulation are still poorly understood due to the limitations of classical pharmacological and genetic approaches. Here we report an improved chemical optogenetic toolkit that permits the reversible and repeatable activation of specific mGluRs with genetic targeting, subtype‐specificity and spatiotemporal precision. Using an updated family of azobenzene‐based photoswitchable glutamate compounds that covalently attach to protein tags, we have dramatically enhanced the efficiency and applicability of these tools. A branched SNAP‐targeting compound termed “doubleBGAG” enables near‐complete photoagonism of mGluR2 when compared to saturating glutamate. The improved efficiency of SNAP‐mGluR2 activation by doubleBGAG permits superior optical inhibition of cortical neurons. Strikingly, doubleBGAG also drastically improves the efficiency of photoagonism of SNAP‐mGluR3 from <10% to ~85% compared to saturating glutamate, allowing investigation of group II mGluR signaling with enhanced subtype specificity. In addition, development of a chimera‐based approach allows for photoactivation of mGluR5 signaling with sub‐cellular targeting. Branched photoswitches targeting CLIP or Halo‐tags along with spectral variants allow multiplexing optical control of multiple receptors. Toward the ultimate goal of targeted delivery of photoswitches to native mGluRs, doubleBGAG also enhances photoswitch efficiency when conjugated to GFP‐targeting nanobodies. Finally, we report the development and testing of fluorophore‐conjugated photoswitches, which allow dual photoactivation and detection of mGluR2 in rodent medial prefrontal cortex in acute slice preparations and in vivo. Together this optogenetic toolkit allows for the dissection of mGluR subtype‐specific contributions to physiological and behavioral changes in mouse models of psychiatric disorders.Support or Funding InformationNIH 2018 R35 GM: 1R35GM124731‐01This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.