bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing the Pleiotropic Role of PravastatinTM on the Expression of AQP1 in Vascular Endothelial Cells Cultured under Static, Venous, and Arterial Flow Conditions in vitro
Authors: Crum Raphael J. , Krane Carissa M. 
Published: November 2023

The current surgical procedure to address coronary artery disease (CAD) involves the grafting of the human saphenous vein (HSV) into an arterial environment in the heart in a process called a coronary artery bypass graft (CABG). However, a high percentage of HSV grafts fail within five years due to the development of intimal hyperplasia (IH). The trigger for IH development is currently unknown. It is possible that difference in exposure to venous vs. arterial shear stress plays a role. Statins, a class of cholesterol lowering drugs, have been shown to suppress the early development of IH. Statins have also been shown to differentially regulate the expression of some members of the aquaporin water channel family of transmembrane proteins. Preliminary results suggest that the expression of aquaporin 1 (AQP1), a water channel abundantly expressed in vascular endothelium, is regulated in part by changes in shear stress in human umbilical vein endothelial cells (HUVECs) in vitro. Based on these observations, it is hypothesized that AQP1 may function as an early environmental sensor in HSV grafts to promote IH development, and therefore, may be a novel target for the early intervention and prevention of IH. The aim of this investigation is to determine the effects of changes in shear stress and Pravastatin™ exposure on the gene regulation of AQP1. The time‐dependent effects of venous and arterial shear stress (6 dynes/cm2 and 16 dynes/cm2) on AQP1 protein expression after 0, 24, 48, and 72 hours of static, venous, and arterial flow conditions were assessed using immunocytochemistry (ICC). The expression of AQP1 mRNA isolated from HUVECs cultured under static and flow conditions for 0, 24, and 48 hours with and without Pravastatin™ was analyzed using qPCR. Combined, the results of these experiments will contribute to an understanding of the relationship between the pleiotropic effects of statins and vascular shear stress and the combinatorial role of the two conditions in the early onset and possible prevention of IH in HSV grafts.Support or Funding InformationSupport for this research was funded by the 2015 APS Undergraduate Summer Research Fellowship and the University of Dayton Department of Biology.
Immunological Memory Exacerbates Responses to Repeated Hypertensive Stimuli
Authors: Itani Hana A. , Xiao Liang , Saleh Mohamed A , Wu Jing , Pilkinton Mark , Dale Bethany L. , Barbaro Natalia , Foss Jason , Kirabo Annet , Montaniel Kim , Norlander Allison , Chen Wei , Sato Ryosuke , Navar L. Gabriel , Mallal Simon , Madhur Meena , Bernstein Kenneth , Harrison David 
Published: November 2023

Accumulating evidence supports a role of adaptive immunity and particularly T cells in the pathogenesis of hypertension. Formation of antigen‐specific memory T cells is a cardinal feature of adaptive immunity. We hypothesized that memory T cells contribute to long‐term renal damage in response to repeated hypertensive challenges. To impose repeated episodes of hypertension, we utilized two mouse models of repeated hypertensive challenges (L‐NAME/high salt treatment and repeated ang II stimulation) and show that effector memory T (TEM) cells are formed upon these repeated challenges and contribute to both salt‐sensitive and ang II‐induced hypertension. L‐NAME followed by high salt increased SBP to 147 ± 14 mmHg and caused a two‐fold increase in effector memory T (TEM) cells in the kidney and bone marrow (BM), as identified by the surface marker CD44hiCD62Llo. Intracellular staining showed that memory T cells were predominant sources of the inflammatory cytokines IL‐17A and IFN‐g. Development and reactivation of memory T cells require the interaction of CD27 on T cells with CD70 on antigen presenting cells. Flow cytometry revealed that L‐NAME/High salt increased expression of CD70 on splenic macrophages by 5‐fold and dendritic cells by 3‐fold. Because memory T cells are a major source of IFN‐g, we examined the hypertensive response to the L‐NAME/high salt protocol in IFN‐g−/− mice. The hypertension caused by L‐NAME was identical between WT, CD70−/− and IFN‐g−/− mice. In contrast, the hypertension induced by subsequent salt administration was markedly attenuated in CD70−/− mice (123 ± 1.3mmHg, p<0.02) and IFN‐g−/− (127.6 ± 5.5, p<0.04). Interestingly, CD70−/− and IFN‐g −/− mice failed to develop memory T cell formation in the kidney. The L‐NAME/high salt caused striking albuminuria and increased urinary N‐gal in WT mice, and these were absent in CD70−/− and IFN‐g −/− mice. We also defined a novel role of BM residing TEM cells in hypertension, in that these cells exhibited clonality, proliferated and redistributed to the kidney in response to repeated salt feeding. Adoptively transferred TEM cells from hypertensive mice homed to the BM and spleen, and expanded upon salt feeding of recipient mice in both the BM and kidney. Thus, these studies show that formation of long‐lived hypertension‐specific TEM cells that are major sources of inflammatory cytokines. These cells place the host at risk of developing blood pressure elevation and end‐organ damage upon delayed exposure to mild stimuli such as salt feeding or low doses of ang II. These studies provide further insight into how the adaptive immune system promotes hypertension.Support or Funding InformationNIH F32 HL124972‐01
Endothelial‐derived Endothelin‐1 distinctly mediates the development of renal apoptosis in male and female mice
Authors: De Miguel Carmen , Battles Kevin D. , Hamrick William C. , Liu Xiaofen , Pollock David M , Pollock Jennifer S. 
Published: November 2023

Renal injury is known to be preceded by apoptosis and loss of nephrons. The vasoactive peptide endothelin‐1 (ET‐1) is upregulated in renal disease; however, its role in renal apoptosis is not completely understood. These studies were designed to determine the role of vascular ET‐1 in renal apoptosis in response to tunicamycin (TM) in male and female mice. TM is a nucleoside antibiotic often used to induce acute kidney injury. Male and female mice lacking ET‐1 in vascular endothelial cells (VEET KO) and the corresponding flox controls (n=5–9/group) received a single i.p. injection of either TM (1.5 mg/kg) or saline. 24 hours post‐injection, kidneys were isolated and renal apoptosis was detected by TUNEL staining and quantified. TM treatment significantly increased apoptosis in renal cortex and outer medulla of female flox mice (% TUNEL positive area, flox vs. VEET KO; cortex: 5.0±0.7% vs. 3.0±0.3%; outer medulla: 6.7±0.9% vs. 4.1±0.2%; p<0.05), while TM‐induced apoptosis was abolished in female VEET KO mice. Interestingly, in male mice, TM did not induce apoptosis in either genotype. Endoplasmic reticulum (ER) stress is known to induce cellular apoptosis, and our group has recently implicated ET‐1 in the activation of ER stress pathways in the kidney. ER stress marker expression was assessed by qRT‐PCR in renal vessels isolated from TM‐treated male and female VEET KO and flox control mice. TM significantly increased ER stress in renal vessels of flox mice of both sexes. However, the absence of ET‐1 from the vasculature blunted the effects of TM on vascular ER stress in female VEET KO mice, but not in male VEET KO mice. These results indicate that vascular ET‐1 plays a critical role in the development of TM‐induced renal apoptosis and ER stress in female mice, but not in male mice. We propose that renal injury is mediated via sex‐specific mechanisms.Support or Funding InformationFunded by NIH T32 DK007545 to CDM and P01 HL95499 to DMP and JSP
Activated Immune Cells Exacerbate Angiotensin II Induced Hypertension and Renal Damage in the Dahl Salt Sensitive Rat
Authors: Wade Brittany M , Mattson David 
Published: November 2023

In recent years, there has been a reenergized interest in the role of immune cells in the pathogenesis of hypertension. We recently demonstrated attenuated Angiotensin II (AngII) induced hypertension and renal damage in Dahl Salt Sensitive (SS) rats lacking T‐ and B‐ lymphocytes due to a null mutation in the Rag1 gene (SS‐Rag1em1Mcwi). The present study was performed to analyze the abundance of different renal infiltrating immune cells and assess the cytokines produced by these cells during AngII induced hypertension. The continuous infusion of AngII (5 ng/kg/min, iv) to SS and SS‐Rag1em1Mcwi rats fed low salt (0.4% NaCl) chow led to a significantly greater increase in mean arterial pressure (MAP) in SS rats (189±3 mmHg) than in Rag1 mutant rats (177±3 mmHg) after 12 days of infusion (n=9 rats/group). Renal damage, as assessed by albumin excretion rate, was significantly increased after 12 days of AnglI infusion in the SS (from 33±4 to 81±9 mg/day) and in the Rag1 mutants (from 12±2 to 50±8 mg/day); albumin excretion rate was significantly different between the groups at all points measured. To examine the immune cells involved in the phenotypic response of the SS rats, cells were isolated from the kidneys and analyzed by flow cytometry. Compared to vehicle infused rats, kidneys of AngII treated SS rats had increased CD45+ total leukocytes (1,807,134±235,766 vs. 4,434,147±1,295,814 cells/kidney), CD11b/c+ macrophages/monocytes (1,439,002±163,119 vs. 3,566,048±1,124,655 cells/kidney), and CD3+ T Cells (299,557±81,501 vs. 740,370±155,065 cells/kidney). Further experiments were performed to assess the abundance of cytokine secreting CD3+ cells in the kidneys of AngII and vehicle infused SS rats. These experiments revealed 57% more CD3+/IL17+ T cells from the rats treated with AngII than the vehicle infused group (n=5–6 rats/group). This difference in IL‐17 production was observed in both CD3+/CD4+ and CD3+/CD8+ T cells. There was a tendency for more CD3+/IFNγ and CD3+/TNFα cells from the AngII infused group as well, though the changes were not significant. The present data suggest that infiltrating T cells in the kidney may secrete IL17 or other cytokines to exacerbate renal damage in AngII induced hypertension.Support or Funding InformationSupported by DK‐96859 and HL116264
Hydrochlorothiazide Does Not Acutely Acidify Urine
Authors: de Bruijn Pauline , Brekelmans Renee , Praetorius Helle , Leipziger Jens 
Published: November 2023

Urine acidification is fine‐tuned in the collecting duct. The α‐intercalated cells in this segment express the apical H+‐ATPase, which activity is assumed to be dependent on the transepithelial voltage (Vte). The lumen‐negative Vte generated by Na+ influx via the epithelial Na+ channel (ENaC) is believed to promote H+‐ATPase‐dependent H+ secretion. An increased Na+ delivery to the collecting duct would result in additional Na+ uptake through ENaC, increased lumen‐negative Vte, and thus, favor acid secretion via the H+‐ATPase. This mechanism has been the main explanation for the marked urine acidification by loop diuretics. However, we recently showed that urine acidification by furosemide occurs independent of ENaC activity. We demonstrated that furosemide directly stimulates H+ secretion in the thick ascending limb via the Na+/H+ exchanger NHE3. Here, we investigate whether hydrochlorothiazide, an inhibitor of Na+, Cl− cotransporter (NCC) in the distal convoluted tubule causes acute alterations of urine pH. NCC inhibition should similar to the loop diuretics lead to increased Na+ delivery to the collecting duct and, thus, cause urine acidification.Mice were anesthetizes and infused (0.5 ml/h) via a jugular vein catheter with control or hydrochlorothiazide (HCT) (30 mg/kg/h) and bladder was catheterized. Urine pH was measured directly in the outflow of bladder catheter and urine Na+ and K+ were measured using flame photometry.HCT increased urine flow rate from 8.1±1.8 to 15.8±2.6 μl/h/g BW (n=11). Na+ excretion was increased from 20.81±4.15 to 51.8±7.73 μmol/h, whereas no change in K+ excretion was observed. These results clearly demonstrate the diuretic properties of HCT. Interestingly, urine pH was unchanged during the entire infusion period of HCT (1h) compared to control (pH 6.13±0.23 vs 6.15±0.16).Hence, despite the natriuresis induced by HCT, an acute increased H+ secretion was not observed. These results therefore challenge the current understanding of loop‐diuretic‐induced urine acidification, because other means for increasing Na+ delivery to the collecting duct do not acidify urine. Thus, this study supports our previous finding that H+ secretion by furosemide takes place already in the thick ascending limb and will contribute to a better understanding of how the kidneys secrete acid.
A Renal Olfactory Receptor Aids in Kidney Glucose Handling
Authors: Shepard Blythe D , Cheval Lydie , Koepsell Hermann , Doucet Alain , Pluznick Jennifer L 
Published: November 2023

Olfactory receptors (ORs) are G protein‐coupled receptors which serve to detect odorants in the nose. Recently, ORs have been shown to play novel roles beyond odorant detection in a number of tissues, and we previously determined that a subset of ORs are expressed in the kidney. One of these ORs is Olfr1393, which we now report plays a novel role in renal glucose handling. In the absence of a reliable Olfr1393 antibody, we localized this receptor using reverse‐transcribed RNA from microdissected renal segments. These studies showed that Olfr1393 is exclusively expressed in the proximal tubule (PT; S1, S2 and S3), the site of renal glucose reabsorption (n=3 mice, PCR products sequenced to confirm). When stably expressed in polarized MDCK cells, Olfr1393 localizes to the apical plasma membrane, but not to cilia, indicating that Olfr1393 likely localizes apically in vivo. We generated whole‐animal Olfr1393 knockout (KO) mice and found that they are similar to wild‐type (WT) littermates with regard to plasma electrolytes, blood pressure and GFR (measured via iStat, tail cuff and elimination kinetics of plasma sinistrin, respectively). However, Olfr1393 KOs exhibit urinary glucose wasting (1.4× increase in glucose/creatinine vs WT; P = 0.01) despite being euglycemic under both fed and fasted conditions, with normal insulin levels. Olfr1393 KOs also have improved glucose tolerance as measured by a glucose tolerance test (area under curve: WT 20.4 ± 1.6 vs KO 16.3 ± 1.1; P = 0.008). Consistent with a role in renal glucose reabsorption, Olfr1393 co‐immunoprecipitates with Sglt1 and Sglt2, the two Na+/glucose co‐transporters responsible for apical glucose reabsorption. When Sglt1 and Sglt2 were localized within the kidney, we detected a 22% decrease in the luminal expression of Sglt1 in Olfr1393 KO mice, but no change in Sglt2. These data suggest that Olfr1393 is a novel regulator of Sglt1. In addition, as Olfr1393 is an orphan receptor with no known ligands, we utilized a large scale screen of over 1400 chemicals to determine the ligand profile of Olfr1393 (see abstract 987). Together, this data offers new insight into potential pathways of physiological regulation for this novel signaling pathway.Support or Funding InformationNIDDK, ASN
Conditional knock‐down of Kidney‐specific Klotho Gene Impairs Sodium Reabsorption by Downregulating Epithelial Sodium Channel Expression
Authors: Ali Quaisar , Lin Yi , Wang Xiuqing , Sun Zhongjie 
Published: November 2023

Background & PurposeAging is associated with an increased risk of abnormal sodium metabolism. The levels of Klotho, an anti‐senescence gene recedes with age. The Na‐transporters in the distal tubules finely regulate sodium re‐absorption. Klotho is primarily expressed in the renal distal tubules. However it is not known if klotho directly regulates sodium excretion. The purpose of this experiment is to investigate if conditional knockout of renal klotho affects tubular function.Methods & ResultsBriefly, kidney specific cre and klotho floxed mice were bred to generate kidney‐specific Cre‐loxP mice. Daily food and water intakes and urine output were monitored in Klotho floxed (control) and KspKL−/− mice for 12 days using metabolic cages. Food and water intakes, urine flow (UF), urinary sodium (UNaV), sodium balance (Na‐balance) and potassium excretion (UkV) were not different between KspKL−/− and control mice either during the baseline or five days of tamoxifen injection. Daily Injection of tamoxifen for 5 days efficiently knocked down kidney klotho (KspKL−/−). Interestingly, conditional deletion of renal klotho caused significant increases in UF, UNaV, and UkV within 3 days. Hematocrit, plasma and blood volume also significantly decreased during this period, suggesting volume depletion. Western blotting analysis showed a significant decrease in the expression of epithelial Na channel alpha (ENaCα) in kidney cortex while expression of ENaCβ or ENaCγ remains unchanged.ConclusionsThis study demonstrates that depletion of klotho causes impairment in Na reabsorption, probably via suppressing ENaCα expression.Support or Funding InformationNIH R01 HL118558, DK093403 HL105302 and HL102074
Lack of an Effect of Collecting Duct‐Specific Knockout of Nitric Oxide Synthase 3 on Renal Sodium and Water Excretion or Blood Pressure During Physiological Conditions
Authors: Gao Yang , Stuart Deborah , Takahashi Takamune , Kohan Donald 
Published: November 2023

Nitric oxide (NO) can act in an autocrine manner to inhibit collecting duct (CD) sodium and water reabsorption. Mice with CD‐specific knockout (KO) of NO synthase 1 (NOS1) have impaired ability to excrete a salt load and have salt‐sensitive hypertension. The CD also expresses NOS3, however the role of NOS3 in regulating CD salt and water reabsorption is unknown. Consequently, mice with CD‐specific NOS3 KO were generated and renal sodium and water excretion and blood pressure assessed. Mice were developed that were homozygous for the loxP‐flanked exons 9–12 (encodes the calmodulin binding site, removal of which renders the protein non‐functional) of the NOS3 gene and hemizygous for a transgene with the aquaporin‐2 promoter driving Cre recombinase; control mice were homozygous for loxP‐flanked NOS3. An organ panel showed predominant kidney‐specific gene targeting, while acutely isolated inner medullary CD from CD‐specific NOS3 KO mice showed complete target gene recombination. Control and CD‐specific NOS3 KO mice were fed a normal (0.3% sodium), high (3.17% sodium) or low (0.03% sodium) salt diet for 7 days each while in metabolic cages. There were no significant differences between control and CD‐specific NOS3 KO mice in food intake, water intake, urine volume, urinary sodium excretion, or urinary potassium excretion on any of the 7 days of normal, high, or low salt diets. Mice were implanted with telemetry devices and blood pressure determined during 7 days of normal, high or low salt intake. Systolic and diastolic blood pressure and pulse rate were not detectably different between control and CD‐specific NOS3 KO mice on any of the 7 days of normal, high or low salt intake. Plasma renin concentration was determined on day 7 of each salt diet and there were no significant differences between genotypes on the varied salt intakes. Mice underwent 1 day of water deprivation or 7 days of water loading (5% sucrose in drinking water). There was no significant difference between control and CD‐specific NOS3 KO mice in food intake, water intake, urine volume or urine osmolality after 1 day of water deprivation or on any of the days of water loading. In summary, these data suggest that CD NOS3 does not play a critical role in the physiological regulation of renal sodium and water excretion or blood pressure. Whether CD NOS3 is involved in the regulation of renal function under hypertensive conditions remains to be determined.Support or Funding InformationThis research was supported by NIH P01 HL095499
AQP1 in Peritoneal Dialysate as Predictive Biomarker of Integrity of the Peritoneal Barrier and Ultrafiltration Efficiency
Authors: Procino Giuseppe , Nicoletti Maria Celeste , Corciulo Simone , Corciulo Roberto , Russo Roberto , Grandaliano Giuseppe , Carmosino Monica , Svelto Maria , Gesualdo Loreto 
Published: November 2023

BackgroundThe water channel Aquaporin 1 (AQP1) plays a pivotal role in the mechanism of free water ultrafiltration during peritoneal dialysis (PD). Wether or not AQP1 is exclusively expressed in peritoneal capillaries or also in the mesothelial cells (MC) is still debated. It has been hypothesized that decreased expression or function of AQP1 may be responsible for some cases of ultrafiltration failure (UFF). Plasma membrane proteins are released in biological fluids through the exosome pathway to an extent proportional to their abundance at the plasma membrane.MethodsIn this work we investigated the localization of AQP1 in human peritoneum and its presence in exosomes isolated from PD effluent.ResultsProteomic analysis of peritoneal‐derived exosomes showed a significant expression of AQP1. Interestingly, the same samples were devoid of the endothelial marker CD31 but were positive for the mesothelial marker mesothelin, thus suggesting a mesothelial, rather than endothelial origin for these vesicles. In human omental biopsies, AQP1 was localized in peritoneal capillaries and at the plasma membrane of MC, where it co‐localized with mesothelin.ConclusionsOur results suggest that AQP1 is expressed in MC and released in the peritoneal cavity through the exosome pathway. This evidence opens the debate on the role of MC in regulating the efficiency of PD and suggests that AQP1 released in the PD effluent may represent a potential non‐invasive biomarker of integrity of the peritoneal barrier.Support or Funding InformationNon‐U.S.