bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism of Central Atypical Cannabinoid Receptor GPR18‐Mediated Hypotension in Conscious Rats
Authors: Penumarti Anusha , Abdel‐Rahman Abdel A 
Published: June 2021

Background and objectivesVascular GPR18 activation causes vasodilation, and our preliminary findings are the first to show: (i) GPR18 expression in tyrosine hydroxylase (TH) immunoreactive neurons in the rostral ventrolateral medulla (RVLM); (ii) RVLM GPR18 activation (Abn CBD) and blockade (O‐1918) dose‐dependently reduced and increased BP, respectively, in conscious male Sprague Dawley rats. Here we tested the hypothesis that NO generation, via ERK1/2 activation, coupled with reduced reactive oxygen species (ROS) generation in RVLM underlies GPR18‐mediated hypotension. We complemented the integrative studies with signaling studies in differentiated PC12 cells (catecholamine expressing cells with neuronal phenotype) to elucidate the molecular mechanisms implicated in GPR18 signaling.Key results: Ex vivo studies, on RVLM neuronal tissues, collected during the hypotensive response elicited by intra‐RVLM GPR18 activation in conscious rats revealed increases in ERK phosphorylation and NO level and reduced ROS in RVLM while GPR18 blockade elicited opposite BP and molecular responses. In PC12 cells, GPR18 is associated with lipid rafts, and its activation replicated the molecular responses obtained in the RVLM.ConclusionGPR18 activation in the RVLM lowers BP by reducing oxidative stress and increasing NO, via ERK1/2 phosphorylation. Similar molecular findings in PC12 cells support the use of this model system in ongoing GPR18 signaling studies. Specifically, pharmacologic/genetic manipulation studies will elucidate the role of the lipid rafts and their major protein, caveolin, in GPR18 signaling.
Lysophosphatidylethanolamine acts on type 1 lysophosphatidic acid receptor in MDA‐MB‐231 breast cancer cells
Authors: IM DONG‐SOON , PARK SOO‐JIN , LEE KYOUNG‐PIL 
Published: June 2021

Lysophosphatidylethanolamine (LPE) is a lyso‐type metabolite of phosphatidylethanolamine, a plasma membrane component. Actions of LPE have been implicated to be mediated through G‐protein‐ coupled receptor (GPCR). GPCRs for lysophosphatidic acid, a structurally‐similar representative lipid mediator, have not been implicated in LPE‐mediated actions in SK‐OV3 and OVCAR‐3 ovarian cancer cells and in the receptor over‐expression systems. In the present study, LPE‐induced intracellular Ca2+ increase was observed in MDA‐MB‐231 cells but not other breast cancer cell lines. LPE‐ and LPA‐induced responses showed homologous and heterologous desensitization. Furthermore, antagonists for LPA1 and LPA3, VPC32183 and Ki16425, inhibited LPE‐induced Ca2+ increase and Knockdown of LPA1 by transfection of LPA1 siRNA also completely inhibited LPE‐induced Ca2+ rise in the cells. Pertussis toxin, a specific inhibitor of Gi/o proteins, edelfosin, an inhibitor of phospholipase C, 2‐APB, an inhibitor of IP3 receptor, completely inhibited LPE‐induced response. However, HA130, an inhibitor of autotoxin/lysophospholipase D, did not inhibit the response. Therefore, LPE is supposed to act on LPA1/Gi/o proteins/phospholipase C/IP3/Ca2+ rise in MDA‐MB‐231 breast cancer cells.This work was supported by MRC program (2009–0083538) and by Basic Science Research Program (2011–0021158) of the NRF of Korea.
Modulation of the cAMP pathway by Pseudomonas aeruginosa quorum sensing molecules
Authors: Stoddart Leigh , Coward William , Williams Paul , Hill Steve 
Published: June 2021

Pseudomonas aeruginosa (PA) uses quorum sensing molecules (QSMs) to coordinate the production of its virulence factors. These QSMs have also been shown to induce responses within the host mammalian cells. We have investigated the ability of two QSMs, the P. aeruginosa quinolone signal (PQS) and N‐3‐(oxododecanoyl)‐L‐homoserine lactone (OdDHL), to stimulate a variety of second messenger pathways within HEK293 cells. Both QSMs had little effect upon calcium release or ERK1/2 phosphorylation. In contrast, when examining basal cAMP levels it was found that PQS had minimal effects but OdDHL caused a marked decrease in the cAMP levels in a concentration dependent manner. Both PQS and OdDHL stimulated a decrease in forskolin stimulated cAMP, with PQS having effects at lower concentrations than OdDHL. This was also true when stimulating cAMP production via adenosine or β‐adrenergic receptors endogenously expressed in these cells. Pertussis toxin treatment was unable to alter the effects on cAMP modulated by PQS and OdDHL suggesting that Gαi/o proteins are not directly involved. Interestingly the phosphodiesterase 4 (PDE4) inhibitor rolipram caused a moderate reversal in the QSM simulated inhibition of cAMP levels. Understanding the effects of QSMs upon the cAMP pathway may uncover a novel target for the treatment of PA infections.This work was supported by a University of Nottingham Bridging the Gaps award.
Minocycline down‐regulated MMP‐9 and PARP in male and female mice in an embolic model of ischemic stroke
Authors: Sazonova Irina Y , Hoda Md Nasrul , Zemskova Marina A , Hess David C 
Published: June 2021

Background and PurposeAcute ischemic stroke is one of the leading causes of morbidity and mortality in the U.S. Recently, minocycline has been shown to provide neurovascular protection reducing acute cerebral injury by means of its efficiency to inhibit MMP‐9 and PARP. However, it is unclear whether minocycline is effective in females. Here, our aim was to determine if there is a sex‐specific change in MMP‐9 and PARP levels in response to minocycline treatment. We analyzed the neuroprotective mechanisms of minocycline in both sexes using an embolic stroke model in mice that closely mimics acute thromboembolic stroke in humans.MethodsEmbolic stroke was initiated by injection of a thrombus to the right middle cerebral artery. Minocycline was tested in adult males and adult ovariectomized females (23±3 weeks old; n=9–23 animals/group). Behavioral outcomes, infarct volumes, and expression of MMP‐9, PARP, and caspase‐3 were assessed.ResultsWithout minocycline treatment, cerebral blood flow, infarct size, and neurological scores were comparable in both males and ovariectomized females. Stroke up‐regulated MMP‐9 and PARP levels in the brain in both genders, and caspase‐3 level in females. Minocycline significantly reduced the infarct volume (P<0.0001), improved neurologic score (P<0.0001) and reduced expression of MMP‐9 (p<0.05) and PARP (p<0.05) in all animals. However, minocycline did not affect caspase‐3 levels.ConclusionIn a thromboembolic stroke model minocycline is neuroprotective inhibiting MMP‐9 and PARP irrespective of mouse sex.Research support: NIH‐R21 award and GHSU start‐up to I.Y.S
CYP2D6 expression is regulated by polymorphisms that affect splicing and trancription: new biomarkers for CYP2D6 activity
Authors: Wang Danxin , Poi Ming J , Sun Xiaochun , Gaedigk Andrea , Leeder J. Steven , Sadee Wolfgang 
Published: June 2021

Cytochrome P450 2D6 (CYP2D6) metabolizes ~25% of clinical used drugs. CYP2D6 variants are currently used as biomarkers to predict CYP2D6 activity, but the relationship between genotype and phenotype is still ambiguous in most individuals except in poor metabolizers. In this study, we showed common SNP located in exon 6 (rs16947, *2) affects exon 6 splicing, resulting in 2 fold reduction in total CYP2D6 mRNA expression via nonsense‐mediated RNA decay. In addition we identified a novel SNP (E‐SNP) located in an enhancer region over 100 kb downstream of CYP2D6 that increases CYP2D6 transcription 2 fold. Testing in a pediatric cohort of 160 individuals with metabolic activity measured as the ratio of dextromethorphan/metabolites (DM/DX), SNP rs16947 alone is associated with reduced metabolic activity, while haplotype containing both rs16947 and E‐SNP has similar metabolic activity as reference haplotype, indicating gain of function E‐SNP can compensate for the loss of function effect of rs16947. Our data also indicate that the key SNP in *41 rs28371725 does not have independent effect on CYP2D6 mRNA level, the in vivo reduced activity effects associated with *41 was resulted from the lack of E‐SNP in *41 haplotype which also contain rs16947. These results suggest that the combination of rs16947 and E‐SNP may become a new biomarker for predicting CYP2D6 activity.Supported by NIH grant U01 GM092655.
Surgery‐induced inflammation reduces morphine distribution into cerebrospinal fluid
Authors: Wang Yan , Landry Kathryn , Issa Mark , Sleno Lekha , Julian Lisa , Hall Richard , Goralski Kerry 
Published: June 2021

ObjectiveTo determine the effects of surgery‐induced inflammation on morphine distribution across blood‐brain barrier (BBB)MethodsBlood and cerebrospinal fluid (CSF) concentrations of morphine were measured in adult patients undergoing aortic aneurism surgery with (n=12) and without (n=13) cardiopulmonary bypass (CPB). Morphine concentrations were determined by mass‐spectrometry. A Q‐plex cytokine ELISA was used to measure plasma and CSF cytokines.ResultsThe surgical inflammatory response was characterized by increased plasma concentrations IL‐6, a known regulator of BBB drug transporters. The plasma area under the curve from 0 to 24 h (AUC0–24h) of interleukin‐6 (IL‐6) was significantly higher (p=0.02) in the CBP (7900±8180 pg/ml h) versus the non‐CPB (1690±1680 pg/ml h) group, indicating that individuals receiving CPB had a more robust inflammatory response. The CSF to plasma AUC0–24h ratio of morphine in the CPB versus non‐CPB groups was 1.06±0.57 and 2.51±2.08 (p=0.03), respectively, indicating that less morphine penetrated into the brain following CPB when a larger inflammatory response was present.ConclusionCSF morphine exposure is lower in individuals undergoing aortic aneurism with CPB. This effect may be due to IL‐6‐mediated changes in blood‐brain barrier drug uptake or efflux transporter function.The HSFC, PEF and CAS funded the project.
Investigating novel mechanisms of chemerin signalling in mature adipocytes
Authors: Dranse Helen J , Muruganandan Shanmugam , Sinal Christopher J 
Published: June 2021

BACKGROUNDChemerin is a recently identified adipocyte‐secreted signalling molecule (adipokine) that plays local and systemic roles in the regulation of adipocyte differentiation, metabolism, and inflammation. Chemerin levels are increased in obese patients, however little is known regarding the signal transduction pathways coupled to chemerin signalling and how altered chemerin levels in obesity affect adipose function.OBJECTIVETo identify key signalling pathways and molecular targets influenced by chemerin signalling.RESULTSMicroarray analysis revealed that a number of genes with important roles in adipose tissue remodeling were up‐regulated following treatment of murine adipocytes with a neutralizing chemerin antibody. Functionally, this resulted in increased matrix metalloproteinase activity and recruitment of macrophages towards adipocyte‐conditioned medium. Treatment with a NFkB inhibitor was able to reverse these effects, suggesting a NFkB‐dependent mechanism.CONCLUSIONSChemerin mediates the expression of genes involved in adipose tissue remodeling and inflammation through a NFkB‐dependent pathway. This novel role for chemerin signalling likely has important effects on adipose tissue when chemerin levels are modified in obesity.Supported by CIHR, NSERC, and Killam Trusts.
Characterization of the anticancer pharmacology of novel jadomycin molecules
Authors: Hall Steven Robert , Robertson Andrew , Jakeman David L. , Goralski Kerry B. 
Published: June 2021

IntroductionJadomycins are natural anticancer products produced by the soil bacteria S. Venezuelae. The object was to examine the cytotoxicity and mechanisms of action of jadomycins in control and taxol, etoposide, and mitoxantrone‐resistant MCF7 breast cancer cells that respectively overexpress the ATP binding cassette (ABC) transporters ABCB1, ABCC1, or ABCG2.Methods and ResultsLactate dehydrogenase (LDH) assays were used to determine the cytotoxicity of jadomycins DNV, L, B, SPhG, F, W, S, and T. All jadomycins were 100% efficacious at killing control MCF7 cells with EC50 values of 4.3 to 42.3 μM. The jadomycins effectively killed the ABCB1, ABCC1, and ABCG2 overexpressing MCF7 cells with a slight 1.5–3.5‐fold reduction in potency relative to the control MCF7 cells. Using PCR cancer gene arrays and quantitative PCR assays, the expression of 15 cancer‐related genes was found to be altered by jadomycin B or S treatment. This included up to a 23.7‐fold increase in the expression of the antioxidant encoding thioredoxin reductase 1 (TXNRD1). Reactive oxygen species (ROS) assays indicated ROS levels are elevated after jadomycin B, S, or SPhG treatment.ConclusionsJadomycin cytotoxicity in MCF7 breast cancer cells is not dependent of ABCB1, ABCC1, or ABCG2 function. The mechanisms of jadomycin action may include the production of ROS and subsequent cellular oxidative damage.This project is funded by NSERC, CIHR, NSHRF, and BHCRI.
Tricyclic compounds inhibit the OATP1A2 transporter
Authors: Lu Jennifer , Moya Liliam Gabriela Guilarte , Leung Yat Hei , Gaudette Fleur , Turgeon Jacques 
Published: June 2021

BackgroundOATP1A2 is a membrane transporter potentially involved in the absorption of various drugs. Previous data demonstrated that the uptake of rosuvastatin through OATP1A2 can be inhibited by several β‐blockers, where carvedilol is the most potent inhibitor. Carvedilol structurally differs from the other β‐blockers tested by its tricyclic moiety. The goal of this study was to determine whether the tricyclic structure of carvedilol is responsible for its strong inhibitory effect on OATP1A2.MethodsA HEK293 cell line overexpressing OATP1A2 was used as model. They were co‐incubated in the presence of rosuvastatin and increasing concentrations of different tricyclic compounds. The amount of rosuvastatin transported in the cells was measured by HPLC.ResultsMost tricyclic compounds evaluated inhibited rosuvastatin uptake through OATP1A2 with different IC50. Our data show that the inhibition is competitive.

Compound
IC50 (μM)
Compound
IC50 (μM)

carazolol
4.0
nortriptyline
14.8

amitriptyline
5.0
chlorpromazine
29.6

imipramine
12.6
desipramine
77.9

trimipramine
13.6
carbamazepine
>;100

doxepin
14.0
carbazole
No effect

clomipramine
14.7
phenothiazine
No effect

ConclusionsThe inhibitory component is made up of the tricyclic ring with a short aliphatic chain. Consequently, drugs with a similar structure may strongly modulate the transport of OATP1A2 substrates.Funding: CIHR, FRSQ, Foundation CHUM
Gap junction blockage in chorioallantoic membrane networks
Authors: Maibier Martin , Nitzsche Bianca , Reglin Bettina E. , Höpfner Michael , Secomb Timothy W. , Pries Axel R. 
Published: June 2021

BackgroundStudies using theoretical models have revealed the necessity of information transfer along blood vessels, most likely mediated via gap junctions, to achieve efficient blood flow distribution in microvascular networks. Its absence might lead to malperfusion. Here we studied the effects of gap junction blockade on vessel diameter in chick chorioallantoic membrane (CAM) networks by intravital microscopy.MethodsBlockers used were carbenoxolone (175 μM, CBX), palmitoleic acid (100 μM, PA) and GAP27 (1000 μM). Maximal vasodilation (acetylcholine 10 μM, adenosine 100 μM, papaverine 200 μM, sodium nitroprusside 10 μM) allowed examining the relative contribution of changes in vessel structure and vascular tone.ResultsAfter 3h, diameters of arteries and veins decreased to 0.55 and 0.54 (relative to PBS control; CBX), 0.77 and 0.81 (PA) and 0.82 and 0.76 (GAP27). For CBX, about half (59%, 46%) of the diameter reduction was caused by structural adaptation, the rest by an increase in vascular tone. After 6h, diameter reduction was unchanged (0.55 and 0.45) but mainly caused by structural adaptation (96% and 88%).ConclusionThe present findings show the importance of gap junction based communication for developing microvascular networks. Gap junction blockade causes a substantial decrease in vessel diameter with an initial increase in vascular tone and a subsequent change of vessel structure.
Aquaporin 1 does not contribute to the progression of abdominal aortic aneurysm in mice
Authors: Stubbe Jane , Johansen Søren H. , Hansen Pernille B.L. , Bie Peter , Jensen Boye L. 
Published: June 2021

Abdominal aortic aneurysm (AAA) is an asymptomatic chronic dilatation of the abdominal aorta observed predominantly in elderly males. The disease is usually first discovered at the time of rupture and often has a lethal outcome. The mechanism of aneurysm progression is not well characterized, but includes extensive vascular remodeling. Aquaporin 1 (AQP1) is necessary for endothelial‐ and vascular smooth muscle cell migration in tumors and in hypoxic conditions. Thus, we hypothesized that deletion of AQP1 attenuates the formation and progression of abdominal aortic aneurysms. 10–12 weeks old male ApoE KO and AQP1‐ApoE dKO mice were fed western diet and given angiotensin II (Ang II, 1 μg/kg/min) via subcutaneous osmotic mini pumps for 28 days in order to increase blood pressure and induce AAA formation. At 28 days mice were euthanized and aorta dissected. As expected plasma Ang II concentration did not differ between ApoE KO and AQP1‐ApoE dKO mice (403 ± 96 pg/ml vs. 370 ± 74 pg/ml, n=10–11, p=0.8). There was no difference in the incidence of AAA formation (64% vs. 61%). AAA sizes were similar in ApoE KO and AQP1‐ApoE dKO mice, as measured by outer abdominal diameter (1.45 ± 0.18 mm vs. 1.25 ± 0.18 mm, n = 10–11, p=0.4), and by wet weight of the abdominal aorta (15.4 ± 3.7 mg vs. 14.7 ± 4.3 mg, n= 10–11, p=0.9). It is concluded that in ApoE KO mice on western diet, AQP1 does not contribute significantly to incidence and progression of abdominal aorta aneurysm.Supported by Alfred Andersen grant and Director Jacob Madsen & Olga Madsen's grant
Nitric Oxide (NO)‐mediated vasodilation is controlled by pannexin‐1‐formed channels
Authors: Puebla Mariela , Gaete Pablo , Lillo Mauricio , Figueroa Xavier 
Published: June 2021

Membrane channels formed by pannexin proteins (Panxs 1–3) are expressed in the vascular wall. However, the function of these channels in endothelial cells remains to be determined. We evaluated the participation of Panx‐1 in the NO‐mediated control of vasomotor tone in isolated mesenteric resistance arteries of rat. The expression of and spatial interaction between Panx‐1, endothelial NO synthase (eNOS) and caveolin‐1 (Cav‐1) were analyzed by immunofluorescence and proximity ligation assay (Duolink® II). Panx‐1 and Cav‐1 were mainly detected in the endothelium, but also in smooth muscle cells. As expected, eNOS was observed exclusivity in endothelial cells in co‐localization with Cav‐1. In addition, Panx‐1 was spatially associated with Cav‐1 and eNOS, which suggests a functional relation between these proteins. Consistent with this notion, blockade of Panx‐1‐formed channels with probenecid enhanced the NO‐dependent vasodilation induced by acetylcholine and increased the level of the activating phosphorylation of eNOS at serine 1177.These results indicate that Panx‐1 participates in the NO‐mediated control of vasomotor tone through the interaction with eNOS in signaling microdomains known as caveolae.Proyects: Anillo ACT‐71, Fondecyt 1100850, 1111033.
Thyroid hormones can increase astrocyte fatty acid oxidation and survival; a possible mechanism for decreased tissue necrosis after cerebral stroke
Authors: Sayre Naomi L. , Holstein Deborah , Lechleiter James D. 
Published: June 2021

Enhancement of astrocyte metabolism in mice significantly decreases lesion size after stroke. This was achieved after purinergic stimulation, but we know that thyroid hormones (TH) can also increase mitochondrial metabolism. Acute treatment with triiodothyronine (T3) increases long‐chain fatty acid oxidation (FAO) in several tissues to improve metabolism. Because astrocytes also use fatty acids for energy, we hypothesized that THs increase astrocyte FAO and improve survival after oxidative stress or stroke.ResultsNanomolar concentrations of either diiodothyronine (T2) or T3 increase astrocyte FAO of [3H]palmitate into 3H2O by over 30% (p<0.01). The astrocyte mitochondrial membrane potential was measured using the potential sensitive dye tetramethyl rhodamine methyl ester. Acute T2 treatment (15 minutes) tripled the dye intensity (p<0.05), indicating improved mitochondrial membrane potential. These data are consistent with increased energy production upon TH treatment. Astrocytes were stressed with hydrogen peroxide, and viability was measured using the vital dye calcien‐AM. T2 and T3 each increased astrocyte viability 25% (p<0.01). To test if TH is protective in vivo, we induced focal ischemia in mice. Administration of T2 decreased the necrotic volume in the brain by half (p=0.02) 24 hours post‐stroke. Future testing will determine if TH‐mediated survival of astrocytes is dependent on FAO.
Validation of submaximal oxygen consumption tests for individuals with spinal cord injury
Authors: McCulloch John P , Aslan Sevda , Lorenz Doulgas , de Paleville Daniela Terson 
Published: June 2021

Spinal cord injury decreases total daily energy expenditure, placing this population at a much higher risk for cardiovascular disease, obesity, and diabetes. However, exercise training individuals with spinal cord injuries have seen improvements in cardiovascular health and overall quality of life. The goal of this study is to establish reliable submaximal oxygen consumption tests for individuals with spinal cord injury. Compared to maximal tests, submaximal oxygen consumption tests are much cheaper, shorter in duration, and pose less of a health risk to the subjects.Participants for this study were individuals between the ages of 18 and 65 with chronic spinal cord injury (n=12). Each participant performed two maximal oxygen consumption tests and two submaximal oxygen consumption tests over the course of four sessions. The tests were performed on a SCIFIT Arm Ergometer and a NuStep T4. Both machines were used for one maximal and one submaximal test, the order of testing was random. Heart rate, blood pressure, rating of perceived exertion, and ECG were all recorded in addition to the metabolic data. We predicted the estimated oxygen consumption values from the submaximal tests would show a strong positive correlation with the oxygen consumption values obtained from the maximal graded tests. Pearson correlation and regression using ordinary least squares was used to find any correlations.