bluuebunny/crossref_metadata_2025_split huggingface dataset:
Defective microglia alters respiratory control and mitochondrial function in mice.
Authors: Rousseau Jean‐Philippe , Laouafa Sofien , Tremblay Marie‐Ève , Joseph Vincent , Kinkead Richard 
Published: November 2023

We tested the hypothesis that alteration of microglial function impairs respiratory control and mitochondrial function in the brainstem of newborn mice. Measurements were performed on newborn CX3CR1 knockout (fractalkine receptor deficient) and control (C57Bl6) mice aged of 1 day. Fictive breathing (in‐vitro) was measured by extracting the brainstem with a part of the spinal cord and placing it in a chamber where it was superfused with an artificial cerebrospinal fluid (aCSF). The output signal from the respiratory network was recorded by a suction electrode placed on the fourth ventral root (C4) representing the inspiratory signal sent to the diaphragm via the phrenic nerve. Mitochondrial function was assessed on fresh brainstem tissue (~4–5 mg) permeabilized with saponin using high‐resolution oxygraph (O2k‐Oroboros) allowing to evaluate simultaneously O2 consumption and H2O2 production (reflect of reactive oxygen species). Compared to controls, CX3CR1KO mice showed 41% decreased phrenic burst frequency under baseline conditions (3.0±1.2 vs 7.3±1.0 bursts/min; P<0.05). O2 consumption measurements under basal condition with substrates of complex I (Pyruvate/Malate) and complex II (Succinate) showed no effects between control and CX3CR1KO (CI: 5.8±0.4 vs 3.9±0.5 pmol O2/s/mg; CII: 10±0.3 vs 7.8±0.6 pmol O2/s/mg). However, addition of ADP stimulated mitochondrial respiratory chain and increased O2 consumption in control more than CX3CR1KO mice with substrate of complex I (29.4±2.6 vs 22.3 ±1 pmol O2/s/mg; P<0.01), complex II (39.5±1 vs 31±1.5 pmol O2/s/mg; P<0.005) and complex I+II (55.5±2.1 vs 41.4±1.4 pmol O2/s/mg; P<0.0001). Moreover, H2O2 production tends to increase in CX3CR1KO mice compared to control with substrates of complexes I and II under stimulation by ADP. We can conclude that CX3CR1KO mice exhibit an alteration of respiratory control as well as a mitochondrial dysfunction. These preliminary results provide new hypotheses regarding the origins of respiratory disorders of the newborn involving reduced respiratory drive such as apnea of prematurity.Support or Funding InformationFounded by NSERC, Région Rhône‐Alpes and consulat de France à Québec.
Effect of circulating angiotensin II on central vascular and inflammatory responses in the rat PVN
Authors: Arocha Rebeca , Zubcevic Jasenka 
Published: November 2023

High levels of Angiotensin II (Ang II) are associated with hypertension and blood brain barrier (BBB) disturbance. We have previously shown that neuronal effects of a single systemic injection of Ang II persist for several hours after the blood pressure returns to baseline. Thus, we hypothesize that a single injection of Ang II may cause microglial activation via BBB disturbance. Adult male WKY rats were injected with bolus saline or Ang II (40μg/kg in 0.5ml saline i.p.). At one and 24 hours post‐injection, brains were collected (2% PFA), cryoprotected (30% sucrose) and frozen in OTC. Sections (10μm) were cut in the paraventricular nucleus (PVN) region (1.44–1.92mm caudal to Bregma). Slides were incubated with mouse anti‐rat transferrin (ThermoFisher Scientific Catalog#: 13‐6800; 1:450), rabbit anti‐rat IBA1 (Wako Pure Chemical Industries, Ltd. Catalog#: 019‐19741; 1:500), and rabbit anti‐rat GFAP (Sigma‐Aldrich Co. LLC Catalog#: G4546‐100UG; 1:400) overnight. Images were taken with a Zeiss fluorescent microscope and analyzed with imageJ. Transferrin levels reduced at one hour (−31.5±6.11, P=0.0143), returning to baseline levels at 24 hours post‐Ang II (+20.8±11.9, P=0.202). Similarly, a significant increase in number of activated microglia was present at one hour (+28.2±4.316%, P=0.0196), which remained high at 24 hours post Ang II (+16.2±2.57%, P=0.0143). In contrast, no significant changes in astrocytes were observed at one hour (−22.2±19.6, P=0.429) and 24 hours post Ang II (+4.5±19.1, P=0.849). We propose that even a single systemic injection of Ang II may exert its central effects via disturbance of BBB.Support or Funding InformationAs part of the STRIDE Undergraduate Summer Research Fellowship, the author was funded by the American Physiological Society and a grant from the National Heart, Lung and Blood Institute (NHLBI;1 R25 HL115473‐01). And would like to thank Dr. J Zubcevic for guidance throughout this experiment.
Purinergic signalling in mesenteric vascular smooth muscle in a mice model of essential hypertension
Authors: López‐López José Ramón , Alvarez‐Miguel Inés , Cidad Pilar , Perez‐Garcia M Teresa 
Published: November 2023

In vascular smooth muscle cells (VSMCs) non‐selective cation channels such as TRPC3 and TRPC6 have been proposed as the molecular constituents of receptor‐(ROCs) and stretch‐(SOCs) operated channels linking DAG signaling cascade pathway with increased vascular tone. The membrane depolarization caused by TRPCs can increase Ca2+ entry leading to augmented [Ca2+]I and VSMC contraction. Therefore, by influencing membrane potential, TRPC channels could play an important role controlling the increased vascular tone present in several pathologies, such as essential hypertension. We have previously described an increased functional expression of TRPC3 channels in mesenteric VSMCs from hypertensive mice that can contribute to increased vascular tone by favouring depolarization (Alvarez‐Miguel et al., J Physiol, in press). As several mechanosensitive G‐protein coupled receptors (GPCR) are linked to the DAG‐dependent activation of TRPC3/6 channels, we explore here the contribution of this signalling pathway to the increased vascular tone in hypertension.Using a mouse model of essential hypertension (BPH mice) and its normotensive control (BPN mice) we explored changes in the molecular components of the mechanotransduction pathway in hypertension. We analized the expression of mechanosensitive ion channels and some VSMCs sensor elements, including GPCRs, channels and transporters with qPCR. Their functional contribution was studied in isolated VSMCs (using electrophysiology) and in intact mesenteric arteries with pressure myography.Real‐time PCR showed an increased expression of some of the elements of the purinergic signalling pathway, including purinergic receptors P2Y2 and P2Y6, TRPC3 channels and the Ca2+‐activated Cl− channel Clca1. Pressure myography of mesenteric arteries after endothelium removal showed a vasoconstriction response to ATP, UTP and UDP. ATP‐induced vasoconstriction was not different between BPN and BPH arteries. The EC50 of the effect was around 7–10 μM in both preparations, and it could be blocked by α‐β‐methilene‐ATP. UTP‐induced vasoconstriction was not affected by α‐β‐methilene‐ATP and was significantly larger in BPH arteries: 50 μM UTP‐elicited vasoconstriction represented 40% of the maximal response to ATP in BPN arteries and 150% in BPH arteries. Our data indicate that mesenteric vascular reactivity to ATP is not altered in our hypertension model, but there is an increased contribution of the purinergic GPCR signalling pathway to the increased vascular tone. Together with the observed upregulation of P2YR receptors in BPH VSMCs, the augmented functional expression of TRPC3 channels could participate in the increased vasoconstriction observed in response to uridine nucleotides in BPH mesenteric arterieSupport or Funding InformationSupported by grants ISCIII‐FEDER RD12/0042/0006, (Heracles Program), BFU2013‐45867‐R (MINECO) and by a Junta de Castilla y Leon fellowship to IAM
Evaluation of biological and mechanical variations in hypertensive animal models
Authors: Lue Sheng‐I , Ho Lilun , Fu Yaw‐Syan , Lu Tzongshi 
Published: November 2023

BackgroundHypertension (HT) is a multifactorial cardiovascular disorder that involves a variety of genetic and environmental factors. To properly study the pathophysiology of hypertension, robust and reproducible experimental animal models are required. The ideal HT animal model should have human‐like cardiovascular anatomy, hemodynamics, and physiology that includes genetic and non‐genetic models. Among these HT animal models, Spontaneously Hypertensive Rats (SHR) with both neural and vascular alterations is the most commonly used genetic HT animal model. In this study, we investigated methodical variations among current HT animal models.MethodsHistamine, Capsaicin, C48/80 or Substance P were administered into the femoral vein of Sprague Dawley rats or SHR to induce endothelial dysfunction. We analyzed mean arterial pressure and analyze plasma extravasation using Evans Blue dye. One way ANOVA with Bonferroni correction, and linear regression were used for statistics. Statistical significances were set at a P< 0.05.ResultsOur data showed significant negative linear regression on the degree of plasma extravasation with blood pressure changes in neurogenic inflammation (Substance P) but positive linear regression in immunogenic inflammation (Histamine, Capsaicin, C48/80). In addition, Evans blue dye inhibited C48/80‐induccd extensive plasma extravasation, mast cell degranulation, and edema significantly.ConclusionsWe have observed significant variations among neurogenic and immunogenic inflammation induced blood pressure changes. Our data shows for the first time that methodical variations observed among animal models, can potentially translate into differential blood pressure patterns, which can be falsely taken to be biologically significant. Our study therefore highlights the pivotal need to carefully consider methodical approaches to animal models that report quantitative differences.
A Slow Pressor Dose of Angiotensin II Decreases Sodium Transporters Expression in the Kidney Cortex and is Independent of PPAR‐alpha
Authors: Khundmiri Syed J , Hardin David , Ecelbarger Carolyn M , Lee Dexter L 
Published: November 2023

A slow pressor dose of Angiotensin II (Ang II) has been shown to increase the expression of sodium transporters in the proximal tubules (NHE3), TALH (NKCC2) and distal nephrons (NCC) of Sprague Dawley rats before an increase in blood pressure. Peroxisome Proliferator Activated Receptor ‐ alpha (PPAR‐alpha) has been shown to be involved in pressure natriuresis through changes in sodium transport via ameloride and thiazide‐dependent mechanisms. We hypothesized that the changes in expression of the sodium transporters during Ang II hypertension were dependent upon PPAR‐alpha expression. To address this hypothesis, we treated wild‐type (WT) and PPAR‐alpha knockout (KO) mice with a slow pressor dose of Ang II (400 ng/kg/min) for 12 days. Mean arterial pressure (MAP) was measured by radiotelemetry. Control MAP was not different between WT (110 ± 8 mmHg) and PPAR‐alpha KO mice (112 ± 12 mmHg). On day 12 of Ang II, MAP for PPAR‐alpha KO (156 ± 16) mice was significantly higher than WT (138 ± 11 mmHg) mice. The expression of NHE3, NHERF1, NKA‐α1 subunit, NKCC2, and NCC was detected in kidney cortical homogenates by western blotting. Kidneys were homogenized and 25 μg of supernatant proteins were separated by 10% SDS‐PAGE, transferred to nitrocellulose paper, and blotted against antibodies to NHE3, NHERF1, NKA α1 subunit, NKCC2, and NCC. The slow pressor dose of Ang II decreased the expression of NHE3 in WT + Ang II (0.14 ± 0.02 ODU) and PPAR‐alpha KO + Ang II (0.10 ± 0.02 ODU), when compared to WT (2.61 ± 0.93 ODU) and PPAR‐alpha KO (2.20 ± 0.58 ODU) controls. Ang II‐treatment also decreased NKCC2 in both WT (0.31 ± 0.10 ODU) and PPAR‐alpha KO (0.22 ± 0.03 ODU). Ang II hypertension caused similar decreases in NCC and NHERF1 expression in WT and PPAR‐α KO mice. NKA alpha1 subunit expression was increased during Ang II hypertension in both WT (1.06 ± 0.26 ODU) and PPAR‐α KO (1.64 ± 0.26 ODU) mice. Our results suggest that the effects of a slow pressor dose of Ang II on expression of sodium transporters are independent of PPAR‐alpha expression. Future studies are needed to determine the effects of decreasing NHE3, NKCC2, NCC and NHERF1 expression in the kidney on urinary salt excretion during a slow pressor dose of Ang II.Support or Funding InformationHoward University Advancing Diversity in Aging Research – National Institute on Aging 1R25AG047843
The effect of Peroxisome Proliferator‐Activated Receptor‐α on NOX‐4 expression in the heart during a slow‐pressor dose of Angiotensin‐II induced hypertension
Authors: Amponsem Joycemary , Lee Dexter L 
Published: November 2023

Aging decreases myocardial peroxisome proliferator activated receptor –alpha (PPAR‐α) expression and activation of PPAR‐α reduces hypertension and cellular oxidative damage. Previous results from our laboratory suggest that PPAR‐α attenuates hypertension and oxidative damage by reducing NOX‐2 expression in the heart during a slow‐pressor dose of Angiotensin II (Ang II). The goal of this project is to determine if PPAR‐α also reduces hypertension and cellular oxidative damage through a NOX‐4 dependent mechanism. We hypothesize that PPAR‐α plays an important role in attenuating the pressor response to Ang II by negatively regulating NOX‐4 expression in the heart. To address this hypothesis, male (48 weeks old) PPAR‐α knockout (KO) mice and wild type (WT) mice were implanted with biotelemetry devices and infused with a slow pressor dose of Ang II (400 ng/kg/min) for 12 days. On day 12 of Ang II, MAP was increased in KO when compared to WT, 167 ± 6 and 145 ± 3 mmHg, respectively. Hearts were homogenized and 25 μg of supernatant proteins were separated by 10% SDS‐PAGE, transferred to nitrocellulose paper, and blotted against antibodies to NOX‐4. The expression of NOX‐4 in the heart was not significantly different between KO and WT controls. NOX‐4 expression was also not different between Ang II‐treated KO (10 ± 10 ODU) and Ang II‐treated WT (12 ± 8 ODU) mice. Despite no differences in NOX‐4 expression in the heart, TBARS, an index of oxidative stress, concentration was increased in PPAR‐α KO + Ang II (12.4 ± 1 μM) when compared to WT + Ang II (10 ± 1 μM). Our results suggest that the differences in the blood pressure response to a slow pressor dose of Ang II between PPAR‐α KO and WT mice are not due to increased NOX‐4 expression in the heart. Previous results from our laboratory suggest that increased NOX‐2 expression in the heart and plasma levels of Interleukin‐17 are mechanisms that may cause a significant increase in the Ang II‐induced slow‐pressor response in PPAR‐α KO mice when compared to WT + Ang II. Future studies are needed to determine if increased NOX‐2 expression alone accounts for the signicant increase in blood pressure and oxidative stress in PPAR‐α KO + Ang II mice. Studies are also needed to determine if increased plasma levels of Interleukin‐17 contributes to the increased blood pressure and oxidative stress in PPAR‐α KO + Ang II mice.Support or Funding InformationHoward University Advancing Diversity in Aging Research – National Institute on Aging 1R25AG047843
INFLUENCE OF DIETARY LARD INTAKE ON THE PROGRESSION OF CARDIOMYOPATHY AND SURVIVAL IN A MURINE DIET INDUCED OBESITY MODEL
Authors: Zemljic‐Harpf Alice E. , Nguyen Alexander H. , Joshi Mughda A. , Alas Basheer F. , Schilling Jan M. , Brenner Sara B. , Nguyen Uyen P. , Roth David M. , Jones Carter W. , Patel Hemal H. 
Published: November 2023

IntroductionObesity poses an enormous healthcare burden and leads to impaired quality of life. We studied effects of a high fat diet (HFD) on the development of obesity related diseases. We hypothesized that increased dietary lard content will reduce survival in a diet induced Type II diabetes model.MethodsThree month‐old C57BL/6J male mice were fed different percentages (%) of kilocalories by fat (4%, 10%, 45%, and 60% lard per kcal) and observed for 31 months, by monitoring 1) food intake 2) body weight, 3) glucose tolerance, 4) cardiac function and remodeling, 5) blood pressure 6) behavior, and 7) survival.ResultsThree months post diet induction, mice on 45% and 60% HFD were overweight, glucose intolerant, normotensive, and presented cardiac hypertrophy with preserved systolic dysfunction. 12 months post diet induction, balance beam, inverted grid, and open field behavioral tests showed correlation between obesity and reduced voluntary physical activity. At 21 months post, 45% and 60% HFD mice compared to animals on 4% and 10% fat diets were hyposensitive to mechanical stimulation but demonstrated evidence of spontaneous pain, showing preference for gabapentin‐paired environments in the conditioned place preference test. Mice on 45% and 60% HFD developed severe dermatitis, presented weight loss and died prematurely without overt signs of heart failure. Given the average lifespan of male C57BL/6J mice between 24 and 30 months, Kaplan‐Meier survival analysis at 24 months after diet induction revealed a mortality of 100% in 60%‐HFD, 75% in 45%‐HFD, 50% in 10%‐group, and 20% in 4%‐group.ConclusionAlthough 45% and 60% HFD induced the same degree of obesity and hyperglycemia, mortality rate was significantly higher in mice on 60% HFD when compared to 45% HFD. These observations in obese and diabetic mice show a correlation between increased dietary‐lard content and higher mortality.Support or Funding InformationVA Merit Grant; BX001963
Hypoxia‐Induced Changes in the Ubiquitin Proteasome System in a Mouse Model of Pulmonary Hypertension
Authors: Wade Brandy E , Zhao Jingru , Ma Jing , Hart C. Michael , Sutliff Roy L. 
Published: November 2023

Pulmonary hypertension(PH) involves a sustained increase in pulmonary arterial pressure and resistance that result in right ventricular(RV) hypertrophy and can ultimately lead to RV failure and death. The mechanisms leading to vascular cell proliferation and vascular remodeling in PH are incompletely defined. The majority of therapeutic approaches target vasodilation but do not address the cellular proliferation and vascular remodeling that underlie PH pathogenesis. The objective of this study is to examine the role of the ubiquitin proteasome system (UPS), an important regulator of protein stability, inhypoxia‐induced PH. Current evidence demonstrates changes in UPS activity in PH; however, the pathways and proteins influenced by these changes are poorly defined. Mice exposed to normoxic or hypoxic (10% O2) conditions for 3 weeks were used to identify proteins with altered ubiquitination in response to hypoxia exposure. Lungs were collected, and the PTMScan® Ubiquitin Remnant Motif (K‐ɛ‐GG) Kit was used to precipitate ubiquitinated proteins for analysis by mass spectrometry (MS). This unbiased MS technique allows identification of changes in ubiquitination of individual peptides as well as global changes in ubiquitin linkage. 198uniquely modified peptides with significant changes in ubiquitination were identified using a fold change threshold of ≥±1.5 (p<0.05). Further analysis revealed a significant decrease in total available ubiquitin though no significant change in total number of ubiquitinated substrates was observed. Hypoxia significantly decreases K11 ubiquitination indicating changes in UPS‐mediated cellcycle regulation. Hypoxia significantly increases K48 ubiquitination suggesting changes in UPS‐mediated protein stability. Increased K48 ubiquitination combined with hypoxia‐induced increases in proteasome and autophagy activity also suggest that ubiquitin‐mediated protein stability may play an important role in PH. These data point to a hypoxia‐induced shift in activity or expression of ubiquitin ligases, the proteins responsible for covalent addition of a ubiquitin moiety to a protein target, and indicate that other shifts in UPS activity may play a significant role in PH pathogenesis.Support or Funding InformationNIH RO1HL102167 (CMH and RLS), Merit Review from VA Office of Research and Development (1I01BX001910 to CMH), and AHA postdoctoral fellowship (16POST30930007 to BEW), SIRE (to JZ)
Anatomic Characterization of Intrapulmonary Bronchopulmonary Anastomoses in Healthy Rat Lungs
Authors: Murphy Austin , Hoover Michael , Galambos Csaba , Bates Melissa 
Published: November 2023

Many neonates with pulmonary hypertension die from right‐to‐left shunt and hypoxemia soon after birth. Intrapulmonary bronchopulmonary anastomotic pathways (IBAPs) have been observed in the lungs of these infants. We indirectly characterized right‐to‐left shunt recruitment by hypoxia (12% O2) in healthy humans and animals that can be reversed by 100% O2. We hypothesized that IBAPs are a normal lung feature whose recruitment is induced by hypoxia. Anesthetized rats were ventilated with 21% or 12% O2 for 20 minutes. Lungs were then immediately removed, airway fixed with 10% formalin, sectioned, and stained for the histological evaluation of IBAPs. The direction of blood flow through these pathways was evaluated by injecting red and green fluorescent microspheres into the right (RV) and left (LV) ventricles of rats ventilated with 12% or 100% O2 and determining their abundance in the lung. Histological sections demonstrated abundant IBAPs in 12% O2‐ventilated lungs, connecting the pulmonary and bronchial arterial trees, but not 21% O2‐ventilated lungs. Consistent with right‐to‐left shunt through these pathways, microspheres injected into the right ventricle were found in the pleural and bronchial vascular beds, but LV‐injected spheres were not found in the pleura. In 100% O2‐ventilated lungs, both RV‐ and LV‐injected microspheres were found coincidentally in pleural vessels, suggesting a possible left‐to‐right shunt. Future studies will aim to anatomically determine the vessel type containing co‐localized red and green microspheres and further characterize IBAPs, including describing their receptor expression.Support or Funding InformationUniversity of Iowa Start‐Up Fund