bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sex Differences in Blood Pressure and mRNA expression of Renal Sodium Transporters in Mice Under Normal Sodium Diet
Authors: Waturuocha Chiedozie , Fan Liming , Kudo Lucia , Gilbert Willie , Rouch Al 
Published: November 2023

We previously reported sex differences in blood pressure and the renal handling of sodium in mice consuming high salt diet (Fan L., et al FASEB J. 30, 731.6, 2016). The purpose of this study was to determine sex differences in blood pressure and mRNA expression of key renal sodium transporters in mice consuming normal chow and water for six weeks. Four‐week old intact male and female CD‐1 mice were purchased from Harlan, Inc. (ENVIGO) (Indianapolis, IN). Female and male mice (n = 5/group) were placed in metabolic cages and consumed normal chow (Harlan Teklad 2019) and water ad libitum for six weeks. Blood pressure in these mice was measured 5 days/week via the tail‐cuff technique (Kent Scientific CODA device). Separate mice in bins were maintained on the same dietary regimen and used for mRNA analysis of renal sodium transporters. Four mice in each group were sacrificed at the end of the first, third, fifth, and sixth weeks. Kidneys were removed, total RNA was extracted from renal cortical tissue and measured for quantity and quality, and this was followed by first‐strand cDNA synthesis. Real time qt‐PCR was performed using Sybr green and the RT2 Profiler™ PCR Custom Array system from SABiosciences (QIAGEN). Arrays contain primers of the following renal transporters ENaC (a, b, g subunits), NKCC2, NCC, NHE2, NHE3, SGLT, Agtr1a, and Atp1a1. Mean blood pressure (MBP, mmHg) averaged weekly was analyzed via two‐way ANOVA with repeated measures. Real time data was determined via ΔΔCt method and analyzed via RT2 Profiler™ PCR Array Data Analysis (Version 3.5) by SABiosciences. Results indicated that female kidneys expressed significantly higher mRNA levels of ENaC (b), NCC, Agtr1a, NHE2, and NHE3 in all four measured periods, higher levels of ENaC (a & g) and SGLT in three of the four periods, and higher NKCC2 levels in one period. Most expression levels were 2 fold or higher in female kidneys. Males had significantly higher MBP than females in week two (82.3 ± 3.5 vs 69.5 ± 2.0, respectively, p < 0.02) and had non‐significantly higher MBP in all other weeks. Both sexes showed increased MBP from week one to week six (female: 72.3 ± 1.1 to 82.2 ± 1.7, p < 0.07; and male: 79.9 ± 3.2 to 88.6 ± 3.2, p < 0.05). We conclude that female mice express higher mRNA levels of renal sodium transporters than male mice and maintain lower MBP than male mice. We suggest that both estrogen and testosterone play important roles in the sex differences in mRNA expression and blood pressure.Support or Funding InformationResearch supported by Oklahoma INBRE 8P20GM103447 Summer Research Program.
The role of Atrial Natriuretic Peptide in the development of renal and cardiac damage in a Dahl SS rat model
Authors: Ilatovskaya Daria , Winsor Kristen , Levchenko Vladislav , Prudnikov Oleh , Blass Gregory , Kriegel Alison , Staruschenko Alexander 
Published: November 2023

Atrial natriuretic peptide (ANP), encoded by the Nppa gene, is an osmoregulatory hormone that promotes salt excretion. A GWAS identified ANP as a causative factor of blood pressure development, and in humans ANP levels are suggested as an indicator of salt‐sensitivity. Recently, Flister et al. (Genome Res, 2013) generated a knockout of Nppa in the Dahl Salt‐Sensitive (SS) rat background (further referred to as the SSNPPA−/− rat). The aim of the current study was to provide mechanistic insights into the effects of ANP deficiency on renal and cardiac function in the Dahl SS rats.In this study hypertension was induced in SSNPPA−/− and control Dahl SS rats by placing them on a high salt diet (HS, 4% NaCl) for 21 days. A combination of in vivo techniques (blood pressure monitoring and GFR measurements) with ex vivo imaging, electrophysiological, and biochemical methods were used to test the role of ANP deficiency in the development of SS hypertension. Immunohistochemical analysis was employed to assess renal and cardiac damage.Chronic i.v. infusion of ANP in wild type SS rats (100 ng/kg/day) attenuated the salt‐induced increase in blood pressure in the wild type SS rats, whereas SSNPPA−/− rats demonstrated a significantly higher mean arterial pressure compared to SS controls when the rats were fed a HS diet: on day 21 of diet MAP was 185.8 ± 9 mmHg in SSNPPA−/− rats compared to 144.6 ± 4 mmHg in SS controls. Additionally, SSNPPA−/− rats showed exacerbated kidney damage as revealed by intensified kidney hypertrophy, higher glomerular injury scores, and increased renal arterial hypertrophy. GFR was found to be reduced in the control SS rats fed a HS diet compared to LS diet, however significance was not reached in the SSNPPA−/− group. SSNPPA−/− rats did exhibit reduced diuresis, as well as a trend for lower sodium and chloride excretion when fed a HS diet. The activity of Epithelial Sodium Channel (an important contributor to the development of SS hypertension) was found to be increased in the cortical collecting ducts of the SSNPPA−/− rats. Additionally, SSNPPA−/− rats fed a HS diet showed intensified cardiac damage compared to SS controls, as demonstrated by higher heart to body weight ratio, and a dramatically elevated interstitial fibrosis. However, ultrasound echocardiography revealed that although SSNPPA−/− rats have cardiac remodeling, they do not exhibit heart failure.Therefore, ANP is major regulator in the development of SS hypertension, and its deficiency leads to more severe cardiac and kidney damage. Further work will be devoted to discovering specific ANP‐associated molecular pathways that mediate its effects in SS hypertension, and assessing the therapeutic benefits of ANP for treating cardiovascular diseases.Support or Funding InformationMCW RAC Pilot Grant (DVI) and NIH HL10880 (AS)
Alpha‐ketoglutarate stimulates Cl− absorption in the mouse CCD through a mechanism dependent on pendrin and protein kinase C
Authors: Fernandez Yoskaly Lazo , Welling Paul A , Wall Susan M 
Published: November 2023

Alpha‐ketoglutarate (aKG) is an intermediary of the citric acid cycle that binds to its G‐protein coupled receptor, OXGR1, in the apical membrane of the kidney type B and non‐A‐non‐B intercalated cells of the cortical collecting duct (CCD) which increases Cl−/HCO3− exchange in the CCD. To determine the intracellular signaling pathways by which aKG stimulates Cl− absorption, we examined aKG‐stimulated Cl− absorption in CCDs perfused in vitro that were taken from mice eating a standard rodent diet. Since pendrin is the major mechanism of apical Cl−/HCO3− exchange in type B intercalated cells, we asked if aKG‐stimulated Cl− absorption is pendrin‐dependent. To do so, we compared the effect of aKG on Cl− absorption in CCDs from pendrin null mice and their wild type littermates. aKG increased Cl− absorption in CCDs from wild type mice without changing transepithelial voltage, VT. However aKG had no effect on Cl− absorption in CCDs from pendrin KO mice. Because aKG's receptor in the type B IC, OXGR1, acts through a Gq‐mediated pathway, we asked if aKG stimulates Cl− absorption through PKC‐dependent signaling. To do so, we examined the effect of aKG on Cl− absorption in the presence of two structurally distinct PKC inhibitors (2.5 mM GF 109203X and 20 nM Calphostin C) or their vehicle. We observed that PKC inhibitor application to the bath solution eliminated aKG‐stimulated Cl− absorption. Moreover, PKCa gene ablation eliminated aKG‐stimulated Cl− absorption. To determine if aKG stimulates Cl− absorption through a Ca2+‐dependent mechanism, we examined the effect of aKG on Cl− absorption with the Ca2+‐chelator bapta (20 μM) or vehicle in the bath solution. We observed that this Ca2+ chelator eliminated the increment in Cl− absorption observed with aKG application. We conclude that aKG stimulates pendrin‐dependent Cl−/HCO3− exchange through a PKC‐ and Ca2+‐dependent mechanism that involves, at least in part, the PKCa isoform.Support or Funding InformationThis study was supported by National Institute of Diabetes and Digestive and Kidney Diseases grants DK‐46493 (to S. M. Wall and T32 DK‐07656 to Y. Lazo‐Fernandez.
Discoverable, Reproducible, and Reusable Biosimulation Models
Authors: Nickerson David , Hunter Peter 
Published: November 2023

Computational models of the heart, arguably the most advanced organ model, have evolved substantially since Denis Noble published his original 1962 modification of the Hodgkin & Huxley equations applicable to Purkinje fibre action and pacemaker potentials. As available computational power has grown the range of cardiac physiology and anatomy able to be represented by the mathematical models and numerical simulations has rapidly increased, to the point where we are now able to make use of multiscale and multiphysics cardiac models in scientific investigations. Similarly, detailed biosimulation models for other organ systems have evolved covering an equally wide range of spatial and temporal scales as well as the required types of physics. Often such models are parameterised for a given scenario, including details such as a specific environment or species. The Virtual Physiological Rat Project (www.virtualrat.org), for example, provided a platform for the consistent parameterisation of a range of biosimulation models for one of the most common laboratory animals.While recent biosimulation models can be very detailed biophysically and anatomically, scientists face many challenges when attempting to reproduce the results of a given study ‐ often as the first exploration step in a desire to reuse an existing model. For instance, cardiac cellular models consisting of large systems of ordinary differential equations are frequently impossible to implement from the published paper alone. To address this problem, the Physiome and Virtual Physiological Human communities have developed standards for encoding model and simulation descriptions which enable scientists to archive and exchange their models in a reproducible manner.The encoded model and simulations alone, however, are often not sufficient to enable scientists to discover suitable existing models or to comprehend a model once it is discovered to enable reuse. Here we will present recent developments aimed at improving the discoverability and reusability of cardiac models. Future work to encourage scientists to make use of these developments will also be presented.Support or Funding InformationSupported by the Virtual Physiological Rat Project, NIH grant [P50‐GM094503]
Autonomic dysfunction precede hemodynamic and metabolic changes in an experimental model of hypertension submitted to fructose overload
Authors: dos Santos Camila Paixão , Bernardes Nathalia , Da Silva Dias Danielle , Conti Filipe Fernandes , Santos Fernando , De Angelis Kátia 
Published: November 2023

The aim this study was to evaluate the effects of 7 days of fructose overload on metabolic, hemodynamic and autonomic parameters in spontaneous hypertensive rats. Male Wistar rats and SHR rats were divided into control (C), hypertensive (H) and hypertensive submitted to fructose overload (HF). The fructose overload (100g/L in drinking water) was started with 30 days of life of the animals. Arterial pressure (AP) signals were directly recorded. Cardiovascular autonomic modulation was evaluated by spectral analysis. Regarding metabolic evaluations, the glucose, insulin resistance and triglycerides were similar between studied groups. The mean arterial pressure, systolic AP and diastolic arterial pressure were higher in hypertensive animals (mean AP, H: 124±2 and HF: 123±3 mmHg) compared to the C group (mean AP: 95±2 mmHg). There was no difference in heart rate among groups. However, the HF group showed lower vagal modulation than C group, evidenced by a reduction in variance of pulse interval (HF: 12±2 vs. C: 37±8 ms2) and RMSSD index (HF: 5.9±0.7 vs. C: 3.3±0.3 ms). Additionally, the HF group showed increase in variance of systolic arterial pressure compared to the C and H group (28 ± 4 vs. C: 13 ± 1 and H: 18 ± 2 mmHg2). In conclusion, only 7 days of fructose overload was able to induce impairment in cardiac vagal modulation and vascular sympathetic modulation with no alteration on metabolic or hemodynamic parameters, suggesting that autonomic modulation dysfunction precede cardiometabolic changes in this experimental model of metabolic syndrome.Support or Funding InformationFAPESP ‐ 2015/11223‐6; CAPES‐PROSUP – 1277269; UNINOVE, CNPq.
Epigenetic Regulation of Macrophage Linage During Acute Lung Injury and Resolution
Authors: Rochford Ian , Joshi Jagdish C , Mehta Dolly 
Published: November 2023

Macrophages coordinate both the initiation and resolution of acute lung injury (ALI), a chronic lung disease which causes significant mortality and morbidity. Macrophages are divided into multiple functionally plastic and phenotypically distinct subpopulations based on their differences in anatomical location and cytokine signaling. Here, we used a mouse model which expresses GFP under the control of the myeloid‐specific Lys‐M promoter and exposed them to pneumonia‐induced ALI to identify shifts in macrophages lineage during inflammatory and resolution phases of lung injury. Flow cytometric analysis showed a dynamic shift in macrophages subpopulations on the onset versus resolution of injury. We found that in naïve lungs, CD11c+/Cd11b+ macrophages, which represent both recruited and lung resident macrophage populations, represent 24.45% of total lung hematopoietic cells. At 4 hours post LPS inhalation, which marks the peak of injury phase, this population decreased to 6.7%. C11b+/CD11c+ then rebound back and their number increased to 59.34% and 49.74% respectfully, during resolution of injury at 24 and 48 hours. On the other hand, CD11c+/CD11b‐macrophages, which constitute alveolar macrophages population, continue to drop from a value of 34.6% at basal state to 29.5% during injury at 4 hours and to 5.9% at 24 hours post LPS. Interestingly, a CD11c+/CD11b (Low) population emerged at 48 hours amounting 17.9% of total macrophages. QPCR analysis of lungs indicated an increase in the expression of HDAC1, an epigenetic modifying enzyme, also at 48 hours. LyzM‐GFP bone marrow derived macrophages also showed distinct morphological phenotypic changes after stimulation with LPS from 0, 4, 18 and 24 hours, indicating differential lineage. We propose that characterization of the genetic and phenotypic signatures of CD11b/Cd11c macrophages of different lineages which disappear and emerge during the onset of injury and resolution phase of ALI may provide insight to their therapeutic potential as a cell‐based therapy for resolving ALI.Support or Funding InformationSupported by PPG2 2POHL077806‐11 and T32‐HL007829
Adenosine 2A (A2A) receptor expression in rats with motor neuron death from intrapleural CTB‐saporin injections
Authors: Craig Taylor A. , Brown Scott M. , Nichols Nicole L. 
Published: November 2023

When injected intrapleurally, cholera toxin B fragment conjugated to saporin (CTB‐SAP) mimics aspects of ALS including the amount of phrenic motor neuron death observed in ALS rats (Nichols et al., 2015). This selective phrenic motor neuron death is sufficient to enhance phrenic long‐term facilitation (pLTF, a form of phrenic motor facilitation; Nichols and Mitchell, ibid, 2014) after 7, not 28, days of CTB‐SAP. pLTF in normal rats predominately requires 5HT2 receptors and the new synthesis of BDNF, although there is an alternative BDNF independent mechanism for pLTF that requires A2A receptors and the new synthesis of TrkB. Preliminary data suggest that the mechanism responsible for pLTF following 7 days of 25mg CTB‐SAP is TrkB dependent (Nichols et al. ibid). Here, we tested the hypothesis that A2A receptor expression is upregulated on phrenic motor neurons following 7, not 28 days, of 25mg CTB‐SAP using immunohistochemistry. A2A receptor expression was studied in Sprague Dawley rats 7 and 28 days following bilateral intrapleural injections of: 1) CTB‐SAP (25μg), or 2) un‐conjugated CTB and SAP (control). Our preliminary data suggest that following CTB‐SAP injection, total A2A receptor positive pixels appear to be increased in the phrenic motor nucleus and non‐phrenic ventral horn at 7 (82±45 and 93±55 pixels, respectively; n=9), not 28 (8 and 8 pixels, respectively; n=2), days later vs. controls (51±24 and 27±15 pixels, respectively; n=6). This suggests that A2A receptors are upregulated to enhance pLTF at 7, not 28, days post‐CTB‐SAP. Future studies will be focused on completing this histology analysis and testing whether pLTF in 7, not 28, day CTB‐SAP treated rats is abolished following C4 intrathecal, A2A receptor antagonist treatment. This project increases our understanding of the expression of receptors associated with respiratory plasticity and its implications for breathing following motor neuron death.Support or Funding InformationSupported by NIH K99/R00 HL119606
Hyperbaric oxygen treatment following mid‐cervical spinal contusion injury ‐ diaphragm outcomes
Authors: Turner Sara M , Schuster Cassandra M , Morton Aaron B , Hinkley J. Matthew , Fuller David D , Smuder Ashley J 
Published: November 2023

Oxidative damage to the diaphragm as a result of cervical spinal cord (cSCI) injury promotes muscle atrophy. However, prevention of cSCI‐induced oxidative stress in the diaphragm via antioxidant therapy can reduce diaphragm atrophy. Hyperbaric oxygen treatment (HBOT) can modulate expression of reactive oxygen species (ROS) and antioxidant enzymes in skeletal muscle. Although mounting evidence suggests HBOT exposure acutely following spinal cord injury (SCI) is associated with a small but functionally beneficial impact on spinal cord pathology, the impact of HBOT on skeletal muscles after SCI is unknown. We tested the hypothesis that HBOT exposure initiated immediately following cervical SCI would alter the expression of diaphragm genes and proteins related to oxidative stress and skeletal muscle atrophy. Rats were randomly divided into the following groups: 1) naïve (no prior treatment), 2) lateral contusion at C3/4 (cSCI) and, 3) cSCI + daily HBOT. The HBOT consisted of a 1‐hr exposure to 2.0 atmospheres of 100% O2, beginning on the day of SCI and continuing for 10‐days. After the 10th treatment day, diaphragm muscle was harvested for analyses of mRNA and protein expression related to muscle proteolysis, oxidative stress, and mitochondrial function. Compared to naïve rats, the cSCI cohort showed increased expression (p<0.05) of markers related to atrophy (Atrogin‐1, MuRF‐1, IL‐1, TWEAK), oxidative stress (ROS, 4‐HNE), and mitochondrial dysfunction (decreased respiratory chain ratio; RCR). The cohort of cSCI rats treated with daily HBOT had significantly lower expression of the markers of proteolysis and oxidative stress, and a significantly greater RCR compared to untreated cSCI rats (p<0.05). In addition, daily HBOT increased antioxidant enzyme expression (SOD2, GPX1). Our data show that daily HBOT has a substantial impact on the diaphragmatic response to cervical SCI. In particular, the reduction in atrophy‐related gene expression raises the possibility that HBOT may have value as an adjunctive therapy to promote health in the phrenic neuromuscular system following cervical SCI.Support or Funding InformationCraig H. Neilsen Foundation 313369 (SMFT); 1 R01 NS080180‐01A1 (DDF), State of Florida Brain and Spinal Cord Injury Research Program (DDF)
Toll‐like receptor 9‐dependent phosphorylation of AMPKα occurs via TAK1 and inflammatory signaling in vascular smooth muscle cells
Authors: McCarthy Cameron G. , Wenceslau Camilla F. , Ogbi Safia , Szasz Theodora , Webb R. Clinton 
Published: November 2023

Toll‐like receptor (TLR)9 is a pattern recognition receptor of the innate immune system. Recently, a non‐canonical stress tolerance pathway was proposed for TLR9 in non‐immune cells, independent of (canonical) inflammatory signaling. It was reported that TLR9 inhibited sarco/endoplasmic reticulum Ca2+‐ATPase (SERCA)2, increasing cytosolic Ca2+, and resulting in 5′ AMP‐activated protein kinase (AMPK)α activation. In our laboratory, we have reported that TLR9 treatment causes arterial dysfunction in vivo, as well as AMPKα phosphorylation (Thr172) ex vivo. However, this dysfunction and phosphorylation does not appear to be initiated by SERCA inhibition. Therefore, the mechanism by which AMPKα is phosphorylated in the vasculature is still unknown, as well as whether it contributes to TLR9‐mediated arterial dysfunction. We hypothesized that transforming growth factor β‐activated kinase 1 (TAK1), a kinase involved in TLR9 inflammatory signaling, was mediating AMPKα phosphorylation. Vascular smooth muscle cells (VSMCs) cultured from aortae of male Sprague‐Dawley rats were treated with TLR9 agonist (ODN2395; 2 μM) for 20 min. Some cells were pre‐treated with inhibitors of TLR9 (ODN2088; 10 μM), TAK1 [(5Z)‐7‐Oxozeaenol; 100 nM], or AMPKα (compound C; 10 μM) for 30 min. Western blot analysis revealed that ODN2395 increased phospho‐TAK1Thr184/187 (1.4 fold vs. Veh, p<0.05), and this increase was prevented in the presence of ODN2088. As previously reported in isolated arteries, ODN2395 increased phospho‐AMPKThr172 (1.6 fold vs. Veh, p<0.05), and this increase was prevented in the presence of (5Z)‐7‐Oxozeaenol. Finally, ODN2395 increased phospho‐myosin phosphatase target subunit 1 (MYPT1)Thr696 (1.5 fold vs. Veh, p<0.05), and this increase was prevented in the presence of compound C. These results reveal that TLR9‐dependent phosphorylation of AMPKα in VSMCs occurs via TAK1, and that AMPKα activation by TLR9 can mediate arterial dysfunction via inhibition of myosin light chain phosphatase.Support or Funding InformationAmerican Heart Association (AHA) and National Institutes of Health (NIH)