bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of PETN and ISDN on vascular dysfunction and oxidative stress in an experimental model of Diabetes
Authors: Knorr Maike , Oelze Matthias , Schuhmacher Swenja , Wenzel Philip , Hochmuth Christian , Steven Sebastian , Heeren Tjebo , Stalleiken Dirk , Muenzel Thomas , Daiber Andreas 
Published: June 2021

BackgroundVascular complications in diabetes mellitus (DM) are associated with increased reactive oxygen species (ROS) formation. Therefore we tested, if treatment with PETN, which has been shown to induce the antioxidant enzyme heme oxygenase‐1, improves ROS formation and vascular function in a diabetic rat model.Methods/ResultsDM was induced by a single i.v. injection of streptozotocin (STZ, 60mg/kg) in male Wistar rats. After 8 weeks of PETN (15mg/kg/d) vs. isosorbid dinitrate (ISDN, 10 mg/kg/d) vs. isosorbide‐5‐mononitrate (ISMN, 75mg/kg/d) treatment, rats were sacrificed. STZ‐treated rats showed an increase in vascular and cardiac ROS production, detected by HPLC. Endothelial function, measured by isometric tension studies, was impaired. PETN therapy improved almost all parameters more efficiently than ISDN, while ISMN had no protective effects. Some rats were treated with insulin (2.5U/d). Insulin normalized all parameters completely proving that STZ‐induced vascular dysfunction depends on hyperglycemia but not on unspecific toxicity of the compound.ConclusionIn diabetic rats, PETN showed more pronounced antioxidative effects than ISDN. Insulin normalized all parameters and thereby identified the underlying mechanism of cardiovascular dysfunction in STZ‐induced DM to strictly depend on insulin levels highlighting the importance of this model.
A Novel Antagonist for the Thromboxane A2 Receptor
Authors: Khasawneh Fadi T , Ting Harold J 
Published: June 2021

Despite the well‐documented involvement of thromboxane A2 receptor (TPR) signaling in thrombotic diseases, there are currently no antagonists available for clinical use. To this end, previous work has defined the C‐terminus of the second extracellular loop (C‐EL2) of TPR as the ligand binding site, and mapped the amino acids which mediate ligand interaction. Since EL2 contains the ligand binding pocket, we hypothesized that an antibody (referred to as C‐EL2Ab) that targets this domain would exhibit biological activity. On this basis, we investigated the capacity of C‐EL2Ab to block TPR‐dependent platelet aggregation. Our initial results demonstrated the C‐EL2Ab blocked human and mouse platelet aggregation triggered by the TPR agonist U46619, in a dose‐dependent fashion; whereas control experiments revealed that it did not produce any detectable effects on aggregation by ADP. Together, these findings suggest that C‐EL2Ab acts as a selective antagonist for TPRs. Consistent with this notion, we found that C‐EL2Ab displaced a radio‐labeled TPR antagonist (i.e., [3H]SQ29,548) from its platelet TPR binding sites. Finally, using ex vivo experimental settings, it was found that intravenous tail injections of C‐EL2Ab resulted in significant blockade of mouse platelet aggregation by U46619, but not by ADP.In summary, these studies show that C‐EL2Ab dose‐dependently blocks platelet aggregation induced by the TPR pathway, under both in vitro and ex vivo conditions, and that these effects are mediated via direct interaction with the receptor protein. Collectively, these results clearly demonstrate that C‐EL2Ab exerts TPR‐specific anti‐platelet effects, thus making it the first function‐blocking antibody against these receptors. Moreover, the identification of a functionally active TPR sequence will significantly aid molecular modeling study predictions for organic derivatives which possess in vivo activity.
Characterization of the relaxant response to equilin in rat mesenteric arteries
Authors: Filgueira Fernando , Lobato Nubia , Ceravolo Graziela , Dantas Ana Paula , Fortes Zuleica , Webb Clinton , Tostes Rita , Carvalho Maria Helena 
Published: June 2021

AIMPremarin, the most widely used hormone replacement therapy in the USA, represents a complex mixture of at least 10 conjugated equine estrogens. Equilin (EQ – 24%) and estrone (E1 – 48%) are the most abundant of these components. However, their effects on vascular function have not been studied in detail. This study aimed to investigate the direct relaxing effects of EQ, E1, 17α‐estradiol (17α‐E2) and 17β‐estradiol (17β‐E2) in resistance mesenteric arteries from intact (INT) and ovariectomized (OVX) spontaneously hypertensive rats (SHR).METHODS AND RESULTSEQ and 17β‐E2 induced similar concentration‐dependent relaxation of rat mesenteric arteries (100% and 90%, respectively). 17α‐E2 and E1 only elicited a maximum relaxation of 56% and 41%, respectively. Similar relaxant responses were obtained in arteries from INT and OVX groups. EQ and 17β‐E2‐induced relaxation is acute, nongenomic, and independent of the endothelium or estrogen receptors. Inhibitors of K+ channels and signaling pathways mediated by adenylyl cyclase, guanylyl cyclase, PKA and PKG did not interfere with the relaxation to these compounds. EQ and 17β‐E2 blocked Ca2+ and Bay K 8644 (L‐type Ca2+ channel activator)‐induced contraction in the presence of KCl.CONCLUSIONEQ and 17β‐E2 act on vascular smooth muscle inhibiting Ca2+ entry via L‐type Ca2+ channels. EQ may be protective against cardiovascular diseases. FAPESP,NIH(HL074167).
Contingent Methamphetamine Administration Decreases Dopamine and Vesicular Monoamine‐2 Transporter Function
Authors: McFadden Lisa M , Vieira‐Brock Paula L , Stout Kristen A , Nielsen Shannon M , Wilkins Diana G , Hanson Glen R , Fleckenstein Annette E 
Published: June 2021

Methamphetamine (METH) is a highly addictive drug with the potential for long‐term health consequences. Although it has been reported in rodent models that METH can have detrimental effects on striatal dopaminergic neurons using non‐contingent dosing regimens, relatively little research has evaluated the effects of METH on dopaminergic neurons using a contingent dosing regimen. Thus, the current study examined if METH self‐administration alters dopamine (DA) transporter (DAT) and vesicular monoamine transporter‐2 (VMAT‐2) function in a manner similar to that caused by non‐contingent administration. Following food training and jugular vein catheter implantation, male rats were given 4 h of access to either 0.06 mg/infusion of METH or saline using a FR1 schedule for 5 d. Rats were sacrificed 1 h after the final session. Results revealed both decreased DAT and VMAT‐2 function in METH compared to saline‐treated controls in striatal tissue. Overall, these results suggest that contingent METH treatment decreases monoaminergic transporter function. The relationship among pressing behavior, METH/amphetamine levels and transporter function will be discussed.Supported by: DA09407, 019447, 013367, 00869, 11389, 04222, 00378
Effects of memantine and donepezil on object recognition memory and hippocampal acetylcholine levels in rats with cholinergic lesions
Authors: Ihalainen Jouni , Sarajarvi Timo , Kemppainen Susanna , Keski‐Rahkonen Pekka , Lehtonen Marko , Banerjee Pradeep K. , Tanila Heikki 
Published: June 2021

The combination of donepezil (DON) and memantine (MEM) produces greater amelioration of Alzheimer's disease (AD) symptoms than DON treatment alone. We sought to elucidate mechanisms underlying that phenomenon.Rats with cholinergic denervation of the hippocampus (fornix lesion) were treated with DON (2.5 mg/kg/day), MEM (30 mg/kg/day), or placebo in drinking water for 3 weeks, then challenged with a single i.p. dose of MEM (5 mg/kg) or DON (2.5 mg/kg). In both treatment phases, animals were subjected to an object recognition task (ORT) and microdialysis measurements of hippocampal ACh levels. Cholinergic denervation was assessed by immunohistochemistry.Fornix lesions resulted in a loss of >50% cholinergic fibers and significantly impaired ORT performance. Three weeks of MEM treatment restored ORT performance and tended to increase ACh levels, whereas DON treatment produced no significant ORT improvement. The MEM challenge following DON or vehicle treatment significantly elevated ACh release, whereas the DON challenge did not affect ACh release. Both challenges improved ORT performance.Our data suggest that MEM restores recognition memory and increases hippocampal ACh release in ACh‐deficient rats. This latter effect, likely resulting from NMDA receptor antagonism, in addition to the normalization of glutamatergic transmission, may underlie the benefits of MEM in DON‐treated patients with AD.
Desensitization of the Dopamine D1‐D2 Receptor Heteromeric Complex in Primary Striatal Neurons and Bi‐functional Regulation by GRK2
Authors: Verma Vaneeta , Hasbi Ahmed , O'Dowd Brian F. , George Susan R. 
Published: June 2021

Co‐activation of a Gq‐linked heteromeric D1‐D2 dopamine receptor signaling complex results in phospholipase C‐dependent intracellular calcium release. We have specifically identified that the D1 agonist, SKF83959, selectively activates the D1‐D2 receptor heteromer, while SKF83822 only activates the D1 homooligomer. These agonists were used to evaluate agonist induced desensitization of the D1‐D2 receptor heteromer mediated calcium signal. Pre‐treatment with each agonist for 5 min led to rapid desensitization of the calcium signal both in cells and in primary striatal neurons. Desensitization was abolished by the D1 antagonist, but not by the D2 antagonist. Expression of G protein‐coupled receptor kinase 2 (GRK2) led to a decrease in the calcium signal. This was mediated by both the catalytic and RGS domains of GRK2. Our results indicate that desensitization of the D1‐D2 receptor heteromer mediated calcium signal occurs by D1 receptor occupancy with or without signal activation and is regulated by two distinct functions of GRK2. Intriguingly, occupancy of the D1 receptor binding pocket by SKF83822 that was unable to activate the D1‐D2 receptor complex still permitted desensitization of the calcium response, suggesting that activation of the receptor was not a prerequisite and occupancy of the receptor binding pocket with its associated conformational changes could lead to decreased signaling.This work is supported by the NIH National Institute on Drug Abuse.
Rgs16 is an early marker for islet formation and beta cell expansion in diabetics
Authors: Ocal Ozhan , Villasenor Alethia , Wang Zhao , Rivera Lee , Asterholm Ingrid Wernstedt , Artyukhin Alexander , Scherer Philipp , Brekken Rolf , Cleaver Ondine , Wilkie Thomas 
Published: June 2021

We seek to identify molecular markers of hormone signaling during early physiologic responses to metabolic stress. Regulators of G protein Signaling (RGS) proteins are feedback inhibitors of ligand‐activated G protein‐coupled receptors (GPCR). We characterized Rgs16 gene expression in BAC transgenic GFP reporter mice during pancreatic development and in diabetic mice. Rg16::GFP is first expressed in embryonic pancreas progenitor cells at E9 and then becomes restricted to endocrine cells during later differentiation. Islet expression of Rgs16::GFP is extinguished by two weeks of age (P14) but persists in Vessel‐ and Ductal‐Associated Cells (VDAC) until P28. Pancreatic expression in adults is reactivated in VDAC and beta cells in regenerating islets of hyperglycemic PANIC‐ATTAC mice (type 1 diabetes model) and in obese ob/ob mice (type 2 diabetes model). Elevated glucose and insulin levels correlate with increased Rgs16::GFP expression in ob/ob mice. Exendin‐4, a Glucagon‐like Peptide‐1 (GLP‐1) homolog that stimulates beta‐cell regeneration and normalization of blood glucose levels in type 1 diabetics, promotes pancreatic Rgs16::GFP re‐expression when co‐injected with glucose. Our results suggest that Rgs16 is likely to control aspects of islet progenitor cell activation, differentiation, and beta cell expansion in embryos and metabolically stressed adults.Funding: NIH (GM061395) to TM Wilkie
PI3K/Akt signaling pathway controls PGE2‐induced ICAM‐1 expression through activation of NF‐kB
Authors: Park Tae yeop , Jung Yi‐Sook , Baik Eun Joo , Moon Chang‐Hyun , Lee Soo Hwan 
Published: June 2021

Prostaglandin E2(PGE2) is known to be the principal pro‐inflammatory prostanoid and play important roles in brain disease through binding to four G protein‐coupled receptor(EP1‐4). However, there have been contradictory reports on its actions in inflammation processes. For instance, PGE2 inhibits or stimulates ICAM‐1 expression depending on the cell type and experimental conditions. In the present study, we investigated whether EP receptor‐mediated elevation of cAMP is necessary for the effect of PGE2 on ICAM‐1 expression in bEnd.3 cerebrovascular cells. PGE2 as well as dbcAMP and forskolin stimulated ICAM‐1 expression, and induced PI3K‐dependent Akt phosphorylation. LY294002, a PI3K inhibitor, attenuated PGE2‐induced ICAM‐1 expression indicating possible involvement of PI3K in PGE2‐induced ICAM‐1 expression. This inference was further supported by the separate experiment using constitutively active and dominant negative Akt constructs. NF‐κB inhibitors such as BAY‐11 and MG‐132 diminished the PGE2‐induced ICAM‐1 expression implicating the role of NF‐κB. This result was further supported by increases in the IκB phosphorylation, translocation of NF‐κB into nucleus and the activity of NF‐κB‐responsive promoter construct. Interestingly, ectopic expression of dominant negative Akt resulted in the reduction of PGE2‐induced IκB phosphorylation. Taken together, these results suggest that PGE2‐induced ICAM‐1 expression is mediated by PI3K‐dependent NF‐κB activation.This study was supported by grants from Ajou University School of Medicine and Gyunggi‐do through CCRB‐GRRC
Longitudinal investigation of permeability and distribution of macromolecules in mouse tumor development and malignant transformation using PET
Authors: Rygh C B , Seo J W , Qin SP , Mahakian L M , Zhang H , Kukis D L , Chan J Q , Cheng‐Liao J , Reed R K , Ferrara K W 
Published: June 2021

Liposomes are widely used as carriers of drugs, genes, or contrast agents while albumin is a commonly used tracer for permeability studies. Here we studied the permeability and distribution of 64Cu‐labeled liposomes and albumin (64Cu‐BAT‐liposomes, Seo et al. Bioconjugate Chem.19: 2577, 2008, and 64Cu‐BAT‐BSA) in a mouse model of ductal carcinoma in situ. Precancer mammary intraepithelial neoplasia outgrowth (MINO, line 4) tissue was transplanted bi‐laterally into gland cleared mammary fat pads in young FVB/N mice (n=8) and were PET scanned (Focus 120, Siemens Medical Solutions, Inc.) at week 3, 5, 7 and 8 after transplantation. Each animal was scanned at multiple time‐points after bolus injection of the tracer to create time‐activity curves (TACs). The apparent permeability of both tracers increased over time as the lesions transformed, and was higher for albumin than for liposomes (from 3.46 ± 0.69 to 12.48 ± 2.94 and 0.81 ± 0.61 to 2.29 ± 0.56 10−8 cm/s for albumin and liposomes at week 3 and 8, respectively). In general, the distribution of liposomes within the tumor was more heterogeneous than with albumin.In conclusion, longitudinal progression of disease could be detected in vivo with PET imaging, as well as heterogeneity of tracer permeability and distribution within the lesions which is valuable information when evaluating drug‐delivery efficacy.This project was supported by NIH CA 103828 and CA 134659
Relationship between total peripheral resistance and measures of central artery wave reflection
Authors: Shepherd John RA , Hart Emma C. , Curry Timothy B. , Charkoudian Nisha , Joyner Michael J. , Casey Darren P. 
Published: June 2021

We examined the relationship between total peripheral resistance (TPR) and central artery pressure and indices of wave reflection in 16 subjects (10F/6M; 26 ± 1 yr). Non‐invasive aortic pressure waveforms were synthesized from high‐fidelity radial pressure waveforms obtained from applanation tonometry of the radial artery. Radial blood pressure (BP) was calibrated from brachial artery BP (catheter). Central artery pressures, aortic augmentation index (AIa), roundtrip travel time of the reflected wave to and from the periphery (Δtp; inverse of pulse wave velocity), and wasted left ventricular energy (Ew) were calculated from the generated aortic pressure waveform. Cardiac output (CO) was measured using an open‐circuit acetylene uptake technique and used to calculate total peripheral resistance (mean arterial pressure/CO). TPR was positively related to aortic pulse pressure (r = 0.49), augmented pressure of the central artery wave (r = 0.60), pulse pressure amplification (r =0.54), AIa (r = 0.53), and Ew (r = 0.66), (P < 0.05 for all). Additionally, TPR was inversely related to Δtp (r = − 0.51, P < 0.05). Our data suggests that increased levels of TPR are related to measures of central artery pressure, wave reflection characteristics and indices of central artery stiffness.Supported by NIH K23 DK‐082424 (TBC), AHA 2170087(ECH) and CTSA RR‐024150
Ursolic acid accentuates contractile and secretory functions in beating rabbit atria
Authors: Cui Hao Zhen , Choi Hye Ran , Cho Kyung Woo , Kang Dae Gill , Lee Ho Sub 
Published: June 2021

Aim of studyUrsolic acid (UA) is a well known hydroxyl pentacyclic triterpenoic acid and has been found in vegetarian foods and medicinal herbs. However, the effects of UA on cardiac functions have not well been documented. The purpose of the present study was, therefore, to address whether UA has contractile and secretory effects in perfused beating rabbit atria.Materials and MethodsThe UA‐induced changes in atrial mechanical dynamics, pulse pressure and stroke volume, cAMP efflux, and ANP secretion were measured in perfused beating rabbit atria.ResultsUA increased atrial dynamics and ANP secretion in a concentration‐dependent manner without changes in atrial cAMP levels. The UA‐induced increase in atrial dynamics was not changed by inhibition of the L‐type Ca2+ channels and SR system. On the other hand, UA‐induced increase in ANP secretion was attenuated by inhibition of L‐type Ca2+ channels.ConclusionThese results indicate that UA accentuates atrial ANP secretion concomitantly with increase of atrial dynamics and also suggest that the accentuation of ANP secretion is related with changes in cellular Ca2+ metabolism.
Phosphoproteomic profile of differentially phosphorylated proteins in human myocardium before and after cardiac surgery utilizing cardioplegia and cardiopulmonary bypass.
Authors: Clements Richard T , Ivanov Alexander R , Smejkal Gary , Bianchi Cesario , Sellke Frank W 
Published: June 2021

ObjectiveCardiac surgery using cardioplegia and cardiopulmonary bypass(CP/CPB) subjects myocardium to reversible ischemic injury that can impair cardiac function. Changes in myocardial contractile activity are likely regulated in part via acute protein phosphorylation. We performed the following study to determine changes in human myocardial protein phosphorylation following CP/CPB.MethodsRight atrial appendage was collected from patients pre and post‐CP/CPB and subjected to two‐dimensional electrophoresis, phospho‐protein staining, image analysis, and tandem mass spectrometry.Results48 spots were consistently increased in the post CP/CPB group vs pre CP/CPB. There were no consistent changes in the remaining 24 consistently detected proteins post CP/CPB. Some of the identified proteins that changed in phosphorylation included: the cytoskeletal proteins tropomyosin α1, cardiac troponin I, atrial myosin light chain (MLC)‐2, atrial MLC‐4, actin, and heat shock protein 27; the metabolic proteins: ATP‐synthase subunit beta, phosphoglycerate mutase 2, and L‐lactate dehydrogenase B chain; the membrane signaling proteins 14‐3‐3εand annexin A5.ConclusionCP/CPB modifies the phosphorylation of specific cytoskeletal, metabolic, signaling, and serum proteins which may have significant implications for CP/CPB‐induced myocardial stunning. (NIH: HL046716,HL093352)
Protection of cardiomyocytes by anesthetic preconditioning involves endothelial cell derived nitric oxide
Authors: Leucker Thorsten Martin , Bienengraeber Martin , Brzezinska Anna K , Pratt Phillip F , Warltier David C 
Published: June 2021

NO is involved in the anesthetic preconditioning‐induced protection against cardiac ischemic injury. The goal of this investigation was to test the hypothesis that endothelial cell derived NO enhaces cellular protection against hypoxia and reoxygenation‐induced cardiomyocyte injury.We studied anesthetic preconditioning in a coculture model of human endothelial cells and HL‐1 cardiomyocytes. Cells were exposed to 0.5 mM isoflurane for 30 min followed by 15 min wash out. Then cells were exposed to 3 h of hypoxia followed by 4 h of reperfusion. To determine cell survival we assessed LDH release and tryptan blue staining.Our results demonstrate that co‐culturing endothelial cells and HL‐1 cardiomyocytes protects from ischemia‐reperfusion injury. Isoflurane exerts protective effects on HL‐1 cardiomyocytes. However, metabolic interactions between endothelial cells and cardiomyocytes exceed the protective effect of isoflurane alone, adding additional layer of cardioprotection. The protective effect of isoflurane is reversed by the NO synthase inhibitor L‐NMMA given prior to reperfusion, but not when given only during isoflurane treatment.In conclusion, during reperfusion, anesthetic induced cardioprotection, in part, depends upon the activity of endothelial NO synthase.
Kidney microRNA expression profile in Ang II‐dependent Hypertension
Authors: Gonzalez‐Villalobos Romer A , Kim Catherine , Neff Ryan M , Satou Ryousuke , Navar L. Gabriel 
Published: June 2021

This study was conducted to determine if there are changes in microRNAs expression in the kidneys during angiotensin (Ang)‐II dependent hypertension. microRNAs are small non‐coding RNAs that cause posttranscriptional repression of their targets with emerging recognition as key players in kidney disease. C57BL/6J male mice (8–9 week) were subjected to sham operation (n=3) or Ang II infusions (400 ng/kg/min, n=3) for 12 days during which systolic blood pressure (SBP) was monitored by tail‐cuff method. RNA was isolated from the kidneys and microRNA expression was determined by microarray. SBP was increased by Ang II (151±3 mmHg) vs. controls (119±0.2, p<0.05). When compared to controls, the expression of 5 microRNAs was reduced in the kidneys of Ang II‐infused mice (p<0.05, results expressed as AU): miR‐22 (4,734 ± 1,327 vs. 2,144 ± 637), miR‐133a (34±5 vs. 22±2), miR‐1187 (619±227 vs. 140±66), miR‐574‐5p (501±193 vs. 148±53), and miR‐669f (110 ±43 vs. 25±13). In turn, the expression of 8 microRNAS was increased: miR‐155 (91±17 vs. 151±28), miR‐128 (145±15 vs. 196±4), miR‐183 (49±6 vs. 75±8), miR‐139‐5p (194±9 vs. 294±33), miR‐132 (84±5 vs. 187±39), miR‐200C (804±147 vs. 1,385±280), miR‐25 (895+89 vs. 1,223±103), and miR‐676 (54±6 vs. 98±11). In conclusion, these results demonstrate that there are significant changes in the microRNA expression profile of the mouse kidney during Ang II‐dependent hypertension.Supported by NIH grants P20RR017659, HL26371, and 1K99DK083455.