bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decreased renal protein expression of adrenomedullin and RAMP2 is associated with impaired pressure‐natriuresis in human GRK4γ 142V transgenic mice (1136.4)
Authors: Zhou Donghai , Jones John E. , Asico Laureano , Jose Pedro A. , Wang Xiaoyan 
Published: June 2021

We have reported that the expression of the human GPCR kinase 4γ142V variant (hGRK4γ142V)in mice causes hypertension, related in part to the dysfunction of renal GPCRs, such as impaired D1 and D3 dopamine receptor function and increased angiotensin type 1 receptor (AT1R)function. The natriuretic and diuretic effects of the D1‐like dopamine receptor agonist fenoldopam are impaired in hGRK4γ142V, relative to hGRK4γ wild‐type (hGRK4γWT) transgenic mice. GRK4 has also been reported to negatively regulate adrenomedullin (ADM), a natriuretic hormone like dopamine. Therefore, we evaluated the expression of sodium transporters, ADM and components of its receptor, RAMP2 (receptor activity modified protein), CLCR (calcitonin‐like calcitonin receptor) and ADMRL2 (ADM receptor L2) in the kidneys of hGRK4□γ142V mice on normal NaCl (0.8%)diet.Blood pressure was elevated in hGRK4γ142V transgenic (129.3±10.4, mm Hg) but not in GRK4γWT (101.7±6.3), relative to non‐transgenic (NT) (99.8±1.8) mice(n=4/group).Theplot of urine sodium excretion and blood pressure in anesthetized GRK4γ142V transgenic mice was shifted to the right of GRK4γWT□transgenic mice.Protein expressions of ADM (‐37±4%) and RAMP2 (‐36±16%) were decreased in hGRK4γ142V transgenic mice, although these remained unchanged in GRK4γWTtransgenic mice, relative to NT mice. CLCR and ADMRL2 werenot altered. Of the 8 sodium transporters, only NKCC2 was increased in GRK4γ142V transgenic mice (+297±72%). ADM immunofluorescence, which was mainly observed in the renal cortex, was decreased in GRK4γ142V transgenic relative to NT mice. Our data suggest that GRK4γ142V and/or the dysfunction of the dopamine and AT1 receptors caused by this variant decreases ADM/RAMP2 expression and increases NKCC2 expression in the kidney.These changes may contribute to the impaired sodium excretion and increased blood pressure in GRK4γ142V transgenic mice.Grant Funding Source: Supported by the National Institutes of Health (HL068686,HL023081,HL074940,HL092916 and DK090918)
A novel mouse model for determining the role of FKBP12 and calcineurin inhibition in tacrolimus‐mediated hypertension and hyperkalemia (1136.6)
Authors: Lazelle Rebecca , Meermeier Nick , Yang Chao‐Ling , Ellison David 
Published: June 2021

The calcineurin inhibitor tacrolimus is widely used to prevent transplant organ rejection. Its use, however, is complicated by hypertension, hyperkalemia, and kidney failure. Tacrolimus suppresses the immune system by binding to an endogenous protein, FKBP12, inhibiting the phosphatase calcineurin. We reported previously that tacrolimus treatment activates the renal sodium chloride cotransporter (NCC), an event necessary to cause hypertension. It is unclear whether tacrolimus activates NCC in the kidney by 1) blocking calcineurin‐independent effects of FKBP12 or 2) inhibiting calcineurin.To address this, we used the Pax8 CRE/LOX system to delete FKBP12 from the renal tubules of mice, upon treatment with doxycycline. Kidney‐specific FKBP12 knockout alone did not increase the abundance of phosphorylated NCC (active), or cause hypertension or hyperkalemia. In contrast, phosphorylated NCC was significantly lower in FKBP12 knockout mice than in wildtype mice (un‐induced), after tacrolimus treatment. These results suggest that tacrolimus inhibition of FKBP12 does not activate NCC directly; instead the drug must bind to FKBP12 and inhibit calcineurin along the nephron to activate NCC. This implies that calcineurin inhibitors that do not bind FKBP12 retain the potential to cause hypertension and hyperkalemia. Understanding how calcineurin regulates NCC, however, may lead to safer immunosuppressive drugs.Grant Funding Source: Supported by RO1 DK095841 02
Purinergic signaling is enhanced in the absence of UT‐A1 and UT‐A3 (1137.10)
Authors: Rogers Richard , Himmel Nathaniel , Redd Sara , Blount Mitsi 
Published: June 2021

The extracellular nucleotide ATP is an important paracrine regulator of renal tubular transport of water and urea. P2Y2, the predominant P2Y receptor expressed in the medullary collecting duct, mediates the action of ATP and thus, is important for urinary concentration. To investigate the role of purinergic signaling in the absence of urea transport in the collecting duct, we housed wild type (WT) and UT‐A1/A3 null (KO) mice in metabolic cages to monitor urine output. Not only did we confirm that KO mice are polyuric, we also observed that urinary cAMP was lower (WT: 3100 ± 467 vs KO: 699.3 ± 95 pmol/ml/creatinine) despite elevated circulating AVP (WT: 8.3 ± 1 vs KO: 28.4 ± 5 pg/ml) in KO mice. Because P2Y2 regulates AVP‐stimulated transport by damping cAMP synthesis, we suspected that, similar to other animal models of AVP‐resistant polyuria, purinergic signaling is increased in the KO mice. In fact, urinary levels of ATP are higher in KO (21.34 ± 5.3 nM/creatinine) compared to WT (5.6 ± 3.5 nM/creatinine) mice and purinergic‐mediated prostanoid (PGE2) production was elevated (WT: 12.4 ± 2.5 vs KO: 32.7 ± 7.1 pg/ml/creatinine). The mRNA expression of P2Y2 was not significantly different in the inner medullas of WT and KO mice which, given the resistance of the KO mouse collecting duct to AVP, was to be expected. Collectively, our data suggest that the reduction in medullary osmolality due to the lack of UT‐A1 and UT‐A3 induces an AVP‐resistant polyuria that is exacerbated by elevated purinergic signaling.Grant Funding Source: Supported by NIH‐NIDDK grants K01‐DK082733 and R03‐DK091501
A mathematical model of rat proximal tubule and loop of Henle (1137.9)
Authors: Weinstein Alan 
Published: June 2021

PT and LOH function are coupled, with proximal transport determining loop fluid composition, and loop transport modulating glomerular filtration via tubuloglomerular feedback (TGF). To examine this interaction, we began with published models of superficial rat proximal convoluted tubule (PCT) (including flow‐dependent transport in a compliant tubule), and rat thick ascending Henle limb (AHL). This PCT was scaled down to represent outer medullary proximal straight tubule (PST), which was connected to thick AHL via a short descending limb. Superficial PT was scaled up to a juxtamedullary nephron, and connected to thick AHL via outer and inner medullary descending limbs, and inner medullary thin AHL. Medullary interstitial solute concentrations were specified. End‐tubule hydrostatic pressure was required to conform to a distal nephron flow resistance. The TGF signal was represented as a linear function of end‐AHL cytosolic Cl concentration. These two distal conditions required iterative solution of the model. Calculations revealed Na, K, and HCO3 reabsorption in all segments, with thin limb transport driven by the increases in lumen concentrations produced by osmotic water reabsorption. PST was a critical locus for NH4 secretion, due to high interstitial NH4, and cellular uptake via the Na,K‐ATPase. Late AHL cytosolic Cl was a sigmoidal function of flow, and appears suitable to represent the TGF signal.Grant Funding Source: Supported by NIH RO1‐DK29857
Effect of purified poloxamer 188 and various dextrans on erythrocyte sedimentation rate in healthy subjects and patients with sickle cell disease (1139.6)
Authors: Hoppensteadt Debra , Emanuele Marty , Molnar Joann , Iqbal Omer , Iqbal Omer , Fareed Jawed 
Published: June 2021

Introduction: Purified poloxamer188 (P188) (Mast Therapeutics) is a non‐ionic, linear block copolymer composed of a central chain of hydrophobic polyoxypropylene and two flanking chains of hydrophylic polyoxyethylene (MW 8.5 kDa). Dextrans represent branched polysaccharides of 10‐70 kDa that have been used as antithrombotic agents and plasma expanders. This study was designed to compare the effect of P188 and dextrans on ESR’s in blood obtained from healthy subjects and patients with sickle cell disease who were seen at Loyola University Medical Center clinics.Material and Methods: Whole EDTA blood collected from normal individuals (n=8) and sickle cell patients confirmed by electrophoresis (n=11) were supplemented with P188 or dextran 10K, 18K , 40K and 70K at various concentrations (or saline control). ESR was measured using standard laboratory technique.Results: The ESR’s for sickle cell patients (26.4 ± 7.1 mm/hr) were significantly higher in comparison to the ESR’s for healthy subjects (14.6 ± 2.1 mm/hr). Supplementation of P188 decreased ESR’s in both populations. Normal blood ESR’s decreased to 9.1 ± 1.3 mm/hr (38%), whereas the sickle cell patient values decreased to 14.1 ± 4.6 mm/hr (47%). At comparable concentrations, none of the dextrans changed ESR’s in healthy subjects or patients with sickle cell disease.Discussion: These results demonstrate that ESR in SCD patients are elevated compared to healthy subjects. P188 supplementation decreased (up to 50%) ESR’s in both the healthy subjects and sickle cell patients.
Molecular effects of Ang II‐mediated differential ACE2 expression in cultured rat astrocytes (1140.2)
Authors: Vudhya Gowrisankar Yugandhar , Clark Michelle 
Published: June 2021

Objective: Angiotensin (Ang) II effects on Angiotensin Converting Enzyme 2 (ACE2) in spontaneous hypertensive rats (SHR) was determined. Background: ACE2 is a negative regulator of the renin angiotensin system catalyzing the conversion of Ang II to Ang‐(1‐7), a peptide that counteracts Ang II effects. Methods: Brainstem (BS) and cerebellum (CB) astrocytes isolated from SHR and Wistar rats were used in this study. Cells were treated with 100nM Ang II at various times and ACE2 protein, and mRNA levels measured using Western blot and qPCR techniques, respectively. Results: Ang II showed a differential pattern to affect ACE2 protein levels in Wistar and SHR astrocytes. Most treatment groups showed ACE2 protein levels significantly reduced compared to basal ACE2 protein. There was a significant difference in Ang II‐mediated ACE2 protein levels in Wistar versus SHR astrocytes. Similarly, Ang II treatment had a differential pattern to modulate mRNA levels of ACE2 in these cells. In SHR CB astrocytes, the pattern of Ang II effects on ACE2 mRNA was significantly different compared to Wistar astrocytes. However, the effects of Ang II were mostly similar in BS Wistar and SHR cells. Conclusion: These findings suggest that the hypertensive state in the SHR may significantly affect Ang II’s ability to influence ACE2 mRNA expression but this effect did not translate into differences in ACE2 protein expression.Grant Funding Source: Supported by Nova Southeastern University Chancellor's Faculty Research & Development Grant # 335872
Long‐lasting inhibitory effect of electroacupuncture in hypertensive patients ő role of catecholamine, renin and angiotension (1140.3)
Authors: Li Peng , Cheng Ling , Liu Dongmei , Painovich Jeanette , Vinjanury Sivarama , Tjen‐A‐Looi Stephanie , Longhurst John 
Published: June 2021

Acupuncture and electroacupuncture (EA) are being used to treat hypertension (HTN). However, its mechanisms are unknown. The present study apply EA in patients with mild to moderate HTN (BP 145‐180/90舉110 mmHg). A group of 42 hypertensive patients without medication were assessed with 24 hr BP monitoring, EA at P 5‐6 and S 36‐37 once weekly for 30 min for eight weeks. After eight weeks treatment, 31 (71%) patients demonstrated significant (P<0.05) reduction at peak (12 mmHg) and average (8 mmHg) SBP/24hrs. The peak and average DBP/24hrs decreased 6 and 5 mmHg,respectively (P<0.05). Heart rate was unchanged. After termination of EA treatment, SBP remained reduced for four weeks but after eight weeks returned to higher levels. Twelve patients (29%) did not respond to the EA treatment. Both SBP and DBP/24hrs were not reduced in 33 other patients treated with control acupoints (LI 6‐7+G 37‐39). This beneficial effect of EA was slow in onset but long‐lasting. After eight weeks of EA treatment, the responders (n=10) plasma concentrations of nor‐sepinephrine decreased from 378±20pg to 278±30pg/ml; renin decreased from 0.568±0.098 to 0.292±0.071 ng/ml.hr, and angiotensin decreased from 0.568±0.098 to 0.262±0.075 ng/ml.hr (All P<0.05). The non‐responders have no significant decrease. Thus, the sympathetic function and renin‐angiotensin system were related to the long‐lasting effect of EA.Grant Funding Source: DANA Foundation, Adolph Coors Foundation, Susan‐Samueli Center for Integrative Medicine and National
Evidence for an angiotensin‐(1‐7) neuropeptidase in the brain medulla of sheep (1140.6)
Authors: Marshall Allyson , Pirro Nancy , Rose James , Diz Debra , Chappell Mark 
Published: June 2021

Angiotensin‐(1‐7) [Ang 7] is an alternative product of the renin‐angiotensin system (RAS). In contrast to Ang II, Ang 7 exhibits central actions to lower blood pressure and improve baroreflex sensitivity. We identified a thiol‐sensitive peptidase that metabolized Ang 7 to Ang‐(1‐4) (Ang 4) in CSF of adult sheep. This activity was 2.5‐fold higher in sheep with antenatal glucocorticoid exposure while CSF Ang 7 levels were 50% lower compared to controls. To characterize this peptidase, we purified the protein 1400‐fold from the brain medulla by multiple chromatography steps monitored by 125I‐Ang 7 conversion to Ang 4. Chelating agents o‐phenanthroline and EDTA, as well as the mercury compounds APMA and PCMB, but not the cysteine protease inhibitor E64 blocked peptidase activity. Specific inhibitors to neprilysin, neurolysin, or thimet oligopeptidase were ineffective while the activity was abolished by the metallopeptidase inhibitor JMV 390 (Ki = 0.7 nM). HPLC analysis confirmed the processing of unlabeled Ang 7 to Ang 4 by the peptidase, but revealed <5% hydrolysis of Ang II or Ang I and no hydrolysis of neurotensin, bradykinin or apelin. Kinetic studies using 125I‐labeled Ang 7 and Ang I show similar Kms (2.6 and 4.3 μM), but a higher Vmax for Ang 7 (72 vs. 6 nmol/min/mg for Ang I, p<0.01, n=3). We conclude that evidence for an Ang 7 neuropeptidase may portend a novel pathway to influence actions of the peptide within the brain.Grant Funding Source: Supported by HD47584
CYP3A5 genotype impacts maraviroc pharmacokinetics in healthy volunteers (1141.15)
Authors: Lu Yanhui , Hendrix Craig , Bumpus Namandjé 
Published: June 2021

We have demonstrated in vitro that the polymorphic enzyme cytochrome P450 3A5 (CYP3A5) plays a major role in the oxidative metabolism of the anti‐HIV drug maraviroc. The present study evaluated the impact of CYP3A5 genotype on the pharmacokinetics of maraviroc. Of the sixteen subjects enrolled, 8 subjects carried the CYP3A5*1 allele (3 CYP3A5*1 homozygous and 5 heterozygous) and 8 subjects did not carry the CYP3A5*1 allele. Subjects received an oral dose of 300 mg maraviroc and blood was sampled over a period of 32 hr. Plasma maraviroc concentrations were determined using liquid chromatography‐mass spectrometry and pharmacokinetic parameters including area under the plasma concentration‐time curve (AUCinf), peak concentration (Cmax), and clearance were calculated. The pharmacokinetic parameters did not differ between the group carrying the CYP3A5*1 allele versus those not carrying a CYP3A5*1 allele. However, the CYP3A5*1 homozygous group exhibited 55% and 52% lower AUCinf, 97% and 84% higher apparent clearance, and 65% and 59% lower Cmax, respectively, as compared to the subjects that were heterozygous for CYP3A5*1 and those not carrying the CYP3A5*1 allele. In conclusion, Cmax and AUCinf were decreased while clearance was increased in subjects carrying two CYP3A5*1 alleles. The results indicate maraviroc has the potential to be used as a CYP3A5 clinical phenotyping probe.Grant Funding Source: Supported by The Johns Hopkins ICTR ATIP Grant
Altered expression of small heterodimer partner governs CYP2D6 induction during pregnancy in CYP2D6‐humanized mice (1141.2)
Authors: Jeong Hyunyoung , Pan Xian , Koh Kwihye , Yu Ai‐ming , Isoherranen Nina 
Published: June 2021

Hepatic drug metabolism plays a key role in determining drug response and safety. Over the decades, substantial progresses have been made in our understanding of the regulation of genes encoding drug‐metabolizing enzymes, providing critical information in developing dosing guidelines. However, current knowledge is insufficient to support dosing guidelines for pregnant women. Specifically, substrates of a major drug‐metabolizing enzyme CYP2D6 display increased elimination during pregnancy, but the underlying mechanisms are unknown in part due to a lack of experimental models. Here, we introduce CYP2D6‐humanized mice as an animal model where hepatic CYP2D6 expression is increased during pregnancy. In the mouse livers, small heterodimer partner (SHP) was downregulated during pregnancy. SHP repressed transactivation of the CYP2D6 promoter by hepatocyte nuclear factor (HNF) 4α. Finally, retinoic acid, an endogenous compound that induces SHP, exhibited decreased hepatic levels during pregnancy. This study provides key insights into mechanisms underlying altered CYP2D6‐mediated drug metabolism during pregnancy, laying a foundation for improved drug therapy in pregnant women.Grant Funding Source: Supported by Grant HD065532 and Fellowship K12HK055892
Biological relevance of PPM1B phosphatase regulation of PXR‐mediated CYP3A expression in hepatocytes (1141.9)
Authors: Pondugula Satyanarayana , Apte Udayan , Flannery Patrick , Abbott Kodye 
Published: June 2021

Variations in pregnane xenobiotic receptor (PXR)‐mediated cytochrome P450 3A (CYP3A) expression can alter therapeutic response to a variety of drugs. It was previously shown that Mg2+/Mn2+‐dependent phosphatase 1B (PPM1B) levels positively regulate human PXR (hPXR) transactivating function and negatively regulate proliferation of HepG2 cells. In the current study, we sought to determine the biological relevance of this regulation. In COS‐7 cells, PPM1B increased hPXR transactivation of CYP3A4 promoter activity and coimmunoprecipitated with hPXR. Elevated PPM1B levels in HepG2 cells led to a significant attenuation of hPXR inhibition by TNFα. This finding, together with the previous finding of PPM1B attenuation of hPXR inhibition by CDK2, suggests that PPM1B counteracts PXR inhibition by proliferation‐dependent signaling pathways in hepatocytes. In mice regenerating livers, gene expression of PPM1B and Cyp3a11 (ortholog of human CYP3A4) was found to be downregulated, although PXR levels were marginally upregulated. Similarly, PPM1B and CYP3A4 gene levels were downregulated in human hepatocellular carcinoma livers with no significant change in hPXR gene levels. Together, these results show that PPM1B interacts with PXR, and increases PXR function by counteracting proliferation‐dependent PXR inhibitory signaling pathways in hepatocytes. Furthermore, downregulation of PPM1B levels in regenerating and hepatocellular carcinoma livers may in part explain a mechanism for repression of PXR‐mediated CYP3A levels in these liver pathophysiologies.Grant Funding Source: Supported by Auburn University Animal Health and Disease Research grant and Start Up funds
The effect of pentadecapeptide BPC 157 in metamphetamine‐induced dopaminergic neurotoxicity (1143.11)
Authors: Suran Jelena , Kolenc Danijela , Prevendar Crnic Andreja , Radic Bozo , Drmic Ivan , Seiwerth Sven , Sikiric Predrag 
Published: June 2021

We investigated the effect of stabile gastric pentadecapeptide BPC 157 (GEPPPGKPADDAGLV, M.W. 1419), an original antiulcer peptide studied in inflammatory bowel disease and now multiple sclerosis clinical trials (LD‐1 not achieved, no side effects reported), in methamphetamine (METH)‐induced neurotoxicity, representing an animal model of monoamine disruption.METH dose of 40 mg/kg b.w. (s.c.) was administered to Wistar rats 24 h prior to random assignment to control (saline, 1 ml/200 g b.w., i.p.) or BPC 157 (10 µg/kg, i.p.) group. Rats were monitored (phenotype, locomotor activity) for 7 days and histopathological analysis of striata was performed.All animals had neurodegenerative phenotype, but these traits became more pronounced in controls compared to BPC 157 rats. Gradual decline in locomotor activity in BPC 157 rats was similar to behavior of healthy rats, while there was a marked hyperactivity in controls 7 days after METH administration. A higher number of red neurons counted in control rat striata and significantly higher number of normal‐appearing neurons in BPC 157 rats imply its beneficial effect on striatum. Therefore, we propose BPC 157as a potential therapeutic agent in monoamine disorders.Grant Funding Source: Supported by Grant 108‐ 1083570‐3635, Croatia
Intracellular chloride concentration and its impact on dichloroacetate metabolism (1143.2)
Authors: Jahn Stephan , Zhong Guo , Smeltz Marci , Rowland‐Faux Laura , Stacpoole Peter , James Margaret 
Published: June 2021

Dichloroacetate (DCA) is an inhibitor of pyruvate dehydrogenase kinase and an investigational drug used to treat mitochondrial disorders, pulmonary arterial hypertension, and cancer. The enzyme that metabolizes it, glutathione transferase Z1‐1 (GSTZ1‐1), is irreversibly inactivated upon metabolism of DCA. This leads to decreased clearance of subsequent doses and a buildup of the toxic physiological substrates of GSTZ1‐1, maleylacetone and maleylacetoacetate, possibly causing the observed side effect of peripheral neuropathy upon chronic administration. We have observed that the extent of this inactivation is dependent on chloride ion concentration, with high concentrations providing a protective effect. Here, we present data measuring intracellular [Cl‐] in human tissues and the effects that it has on the mechanism of inactivation, adduct formation. These results have important implications in the use of DCA, including predicting patient response, and may provide information to advance the use of DCA in patients in which GSTZ1‐1 inactivation leads to adverse effects.Grant Funding Source: This work was supported by the US Public Health Service RO1 GM099871.
Comparison of the norepinephrine transporter blockers cocaine and desipramine in α1‐adrenoceptor studies of rat vas deferens (1145.5)
Authors: Docherty James 
Published: June 2021

A wide range of prazosin pA2/pKB values have been reported in rat vas deferens: varying between 8.32 and 9.35, and the receptors present have been identified as α1A‐, α1D‐ in addition to α1A‐, or α1L‐adrenoceptors (see 1). Studies differ in choice of NET blocker: cocaine or desipramine (DES). We have now investigated the effects of NET blockers on the potency of prazosin at antagonizing contractions to norepinephrine (NE) in epididymal portions of rat vas deferens.Cocaine significantly increased NE potency by revealing the α1D‐adrenoceptor‐mediated component. However, in the presence of cocaine (10 µM), DES (0.1‐10 µM) produced concentration‐dependent inhibition of the response to NE. Prazosin pKB values against NE varied from 8.32 (control), and 8.50 (DES 0.1µM), to 9.05 (cocaine 3 µM), with the lower values indicative of α1A‐adrenoceptor potency, and the higher value indicative of α1D‐adrenoceptor potency. Cocaine and DES (both 0.3 μM) potentiated the contractile response to nerve stimulation, but higher concentrations of DES inhibited the response.Prazosin potency against NE was increased in the presence of NET blockade by cocaine. However, DES does not increase the potency of prazosin as it acts as an α1‐adrenoceptor antagonist over the concentration range that it blocks NET. DES may not be a suitable NET blocker for use in α1‐adrenoceptor studies.(1) Docherty JR (2013). J Auton Autacoid Pharmacol 33, 49‐57.