bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of Myosins IIA and VI in Mediating the in vivo Hormonal Regulation of NHE3 Activity in the Rat Renal Proximal Tubule
Authors: Crajoinas Renato Oliveira , Castelo‐Branco Regiane Cardoso , Malnic Gerhard , Mello‐Aires Margarida , Girardi Adriana Castello Costa 
Published: November 2023

Rapid regulation of NHE3 activity may occur through subcellular redistribution of the transporter between the microdomains of the proximal tubule (PT) microvilli (MV). Myosin motor proteins that move along actin filaments on the MV may mediate NHE3 translocation in response to a variety of stimuli. The present study was undertaken to test the following hypothesis: (i) that myosin IIA may prevent NHE3 stimulation by angiotensin II (Ang II), which is known to increase NHE3 activity at least in part by translocating NHE3 from the base to the body of the PT MV; (ii) that myosin VI may prevent NHE3 inhibition by parathyroid hormone (PTH), which is known to reduce NHE3 activity at least in part by translocating NHE3 from the body to the base of the PT MV. To this end, NHE3 activity of Wistar rats was evaluated by net bicarbonate reabsorption (JHCO3−) of in vivo renal proximal tubules using H+ ion‐sensitive microelectrodes in the presence or absence of 10−10 M Ang II, 10−6 M PTH, 10−5 M blebbistatin (a specific myosin IIA inhibitor) or 4×10−6 M 2,4,6‐triiodophenol (TIP) (a specific myosin VI inhibitor). As expected, Ang II increased [4.36 ± 0.18 nmol/cm2.s (N=25)] whereas PTH reduced [1.18 ± 0.10 nmol/cm2.s (N=17)] NHE3‐mediated bicarbonate reabsorption compared to CTRL [2.74 ± 0.15 nmol/cm2.s (N=9)]. Simultaneous tubular perfusion of Ang II with blebbistatin completely prevent Ang II‐induced NHE3 stimulation [2.92 ± 0.14 (N=21) vs. 4.36 ± 0.18 nmol/cm2.s (N=25), P < 0.001]. Likewise, simultaneous tubular perfusion of PTH with TIP was capable of blocking the inhibitory effect of PTH [2.91 ± 0.15 (N=22) vs. 1.18 ± 0.10 nmol/cm2.s (N=17), P < 0.001] on NHE3 activity. Neither blebbistatin [2.51 ± 0.11 (N=15) vs. 2.74 ± 0.15 nmol/cm2.s, (N=9)] nor TIP [2.49 ± 0.18 (N=14) vs. 2.74 ± 0.15 nmol/cm2.s (N=9)] alone affected baseline NHE3 activity. These results suggest that myosin IIA and VI may play a role in mediating hormonal regulation of NHE3 in the rat kidney proximal tubule.Support or Funding InformationFAPESP
Distribution of M2 and M3 Muscarinic Receptors Across Medullary Respiratory Nuclei
Authors: Burgraff Nicholas , Neumueller Suzanne , Langer Thomas , Bukowy John , Talwar Sawan , Hodges Matthew , Forster Hubert 
Published: November 2023

The M2 and M3 muscarinic receptors in mammals have been shown to be expressed in the brainstem, but there are differences in expression among respiratory nuclei. We previously found in goats that the nonspecific muscarinic receptor antagonist atropine, when dialyzed into rostral pontine respiratory nuclei depressed breathing, whereas atropine dialyzed into the pre‐Bötzinger (preBötz) region increased breathing. Since M2 receptors are thought to decrease breathing, whereas M3 receptors are thought to increase breathing, we hypothesized the stimulation of breathing by atropine dialysis into the medullary nuclei could be because only M2 receptors are expressed in the medulla of goats. Accordingly, we currently investigated the distribution of M2 and M3 receptors in medullary respiratory nuclei. We used immunohistochemistry to quantify the relative distribution of the M2 and M3 muscarinic receptors across respiratory nuclei of the goat medulla. We found that both M2 and M3 receptors were expressed in the pre‐Bötzinger region, hypoglossal nucleus, dorsal motor nucleus of the vagus, nucleus ambiguous, and nucleus tractus solitarius. These data lay the foundation to characterize the expression of the M2 and M3 muscarinic receptors across the goat medullary respiratory nuclei, which is critical for understanding their function in the neural control of breathing.Support or Funding InformationSupported by NIH Grant HL‐112996, HL‐007852, and the Department of Veterans Affairs
Teaching the themes: PhUn Week student‐led stations
Authors: Crecelius Anne R 
Published: November 2023

Physiology Understanding (PhUn) Week is an outreach program that encourages connections between scientists and their local schools. Students (n=25) enrolled in an undergraduate Human Physiology course served as visiting scientist teachers for four 7th grade science classes at a non‐traditional charter school (82 participants). University students designed a brief lesson plan that related to one of the four themes of physiology: 1) Structure and function are closely related; 2) living organisms need energy; 3) Information flow coordinates body functions; and 4) homeostasis maintains internal stability. Each lesson also included a physiology‐related career. Seventh grade participants rotated through the 4 stations for ~10 minutes each. A 6 question assessment was administered to 7th graders pre‐ and post‐visit addressing the definition of physiology (open‐ended), each of the 4 themes (true or false), and careers in physiology (open‐ended). Post‐visit, students’ average percent correct responses on the themes increased ~16% (pre vs post: 58% vs 74%) and the majority of students demonstrated partial or complete knowledge of the definition of physiology and related careers (63% and 59%, respectively). These results suggest brief, theme‐focused stations can be an effective PhUn Week teaching activity for partnering undergraduates and middle‐school students.Support or Funding InformationNone.
Interactions with Volunteers at a Day of Hands‐on Physiology Demonstrations Increases Interest in Scientific Careers in a Native American Indian Population of Middle and High School Students
Authors: Schiller Alicia M , Becker Bryan , Zucker Irving , Godfrey Maurice 
Published: November 2023

PurposeTo provide middle and high school students from Nebraska and South Dakota Native American reservations with an interactive and physiology based educational experience and exposure to scientific careers.MethodsWe partnered with several schools representing middle and high school students from various Native American Indian tribes of Nebraska and South Dakota. Approximately 300 children were bussed in for a day of physiology‐based activities presented by graduate students and faculty. The “Physiology Day” experience included 9 booths focusing on multiple physiological systems. Students spent approximately 25 minutes at the different booths, and each highlighted a different physiological system. Students completed an assessment designed to determine their baseline knowledge and exposure to science as a career prior to engaging in the educational activities. A second assessment was completed following the day of activities to evaluate the effectiveness of the activities to change students’ perceptions and knowledge of physiology.ResultsBefore beginning activities, only 17% of students reported “knowing” a scientist, and this number more than doubled to 44% after interacting with graduate/medical students throughout the event. When students were asked if they “knew anyone that was a healthcare provider” the response pre and post tests were similar (73% vs 76%, respectively). Students were also asked how interested they were in becoming a scientist. At the beginning of the day, almost one quarter (23%) of students indicated that they “did not know” if they were interested in becoming a scientist, which decreased by approximately half (12%) at the end of the day. The proportion of students that indicated that were “very interested” in becoming a scientist increased by 8%. By way of control, students were asked about their interest in health‐related careers by evaluating their interest in working in a hospital or clinic. There was only a 3% decrease in students answering “did not know” to this question in the pre and post‐tests and a 1% decline in students answering “very interested”. Before the activities 64% of students indicated that they believed science to be “very useful”, which increased to 72% of responders following the day of activities.In conclusion, students participating in our physiology‐themed outreach event were able to interact with volunteers at a level sufficient to increase their awareness of individuals that are scientists. Our event also promoted an increased interest in considering a career in science and increased students’ perceptions of the usefulness of science.Support or Funding InformationSEPA (RR032178) (OD011071)
Borderline high blood pressure in people with Miltenberger GP.Mur phenotype is associated with elevated band 3 expression on the erythrocyte membrane
Authors: Hsu Kate , Lin Hui‐Ju , Yao Chin‐Che , Cheng Han‐Chih , Kuo Mei‐Shin 
Published: November 2023

The erythrocyte surface antigen GP.Mur (also known as Miltenberger subtype III, or Mi.III) is one of the most clinically important red blood cell (RBC) antigens in the field of transfusion in Southeast Asia. GP.Mur is a hybrid membrane protein based on the structure of glycophorin B, inserted with a piece of glycophorin A. The incidence of GP.Mur is rare in Caucasians and northern Asians, but between 2 – 6% among Southeast Asians. We previously showed that GP.Mur+ RBCs express 10% or more band 3 (Cl−/HCO3− exchanger) on the erythrocyte surface. GP.Mur promotes structural and functional expressions of band 3. Our most recent human study uncovered that GP.Mur+ healthy people bear larger capacities of HCO3−/CO2 respiration. Unexpectedly, GP.Mur+ subjects also have slightly higher blood pressure than the control subjects.ObjectiveIn this study, we further explored whether borderline hypertension in these healthy GP.Mur+ subjects could be associated with their unusual expression of GP.Mur‐band 3 complexes on the erythrocyte membrane. We quantitated band 3 levels in RBC ghosts, and combined these biochemical data with physiologic measurements from the previous human study.ResultsThe two parameters—blood pressure and band 3 expression, were both higher in GP.Mur+ people, and there were no differences between GP.Mur+/+ and GP.Mur+/−. However, there was a direct correlation between pulse pressure and the concentration of band 3 in GP.Mur+/+ subjects, which was not observed in GP.Mur+/− or the control subjects. By comparison, physiologic HCO3−/CO2 respiration was also slightly faster in GP.Mur+/+ than in GP.Mur+/− subjects.ConclusionFrom these findings, elevated blood pressure and expedited CO2 respiration are likely both resulted from GP.Mur‐assisted higher band 3 expression on the RBC membrane. Further, the biochemical and physiologic differences between GP.Mur+/+ and GP.Mur+/− could be due to their variations in the structural organizations of band 3 complexes on the red cell membrane.Support or Funding InformationSupported by MOST 103‐2320‐B‐195‐001‐MY3 from Taiwan Ministry of Science & Technology
Higher anxiety is associated with elevated inflammation independent of obesity in humans
Authors: Holwerda Seth , Fiedorowicz Jess , Kalil Graziela , Persons Jane , Stroud Amy M. , Ajibewa Tiwaloluwa , Dubishar Kaitlyn , Moser David , Abboud Francois M. , Pierce Gary L. 
Published: November 2023

Obesity and anxiety states are both associated with elevated cardiovascular disease (CVD) risk. Anxiety and obesity are also linked with an increased pro‐inflammatory phenotype; however, the extent to which anxiety is associated with inflammation independent of obesity remains unclear. We hypothesized that anxiety would be independently associated with elevated inflammation in two cross‐sectional samples, one with obesity [body mass index (BMI) ≥ 30 kg/m2] and one with higher anxiety. In cross‐sectional samples of individuals with obesity and at least one CVD risk factor (n=100; 58 ± 8 yrs; BMI: 37 ± 6 kg/m2) or with moderate‐to‐high anxiety (n=38; 36 ± 1 yrs; BMI: 28 ± 1 kg/m2), subjects had assessments of anxiety using the Beck Anxiety Inventory (BAI) and serum highly sensitive C‐reactive protein (CRP) as a generalized marker of inflammation. BMI was significantly correlated with CRP in both groups (obesity: rho=0.42, p<0.001; moderate‐to‐high anxiety: rho=0.46, p=0.004), and BAI scores were also significantly correlated with CRP similarly in both groups (obesity: rho=0.28, p=0.005; moderate‐to‐high anxiety: rho=0.33, p=0.04). In multivariate models in the obesity cohort, the relation between BAI and CRP remained significant (p=0.038), independent of BMI (p=0.02), age and sex. In multivariate models in the moderate‐to‐high anxiety cohort, BAI was only marginally associated with CRP (p=0.10), adjusting for age, sex, and BMI (p=0.007). State‐trait Anxiety Inventory (STAI) scores in the moderate‐to‐high anxiety group demonstrated a marginal association with CRP for trait (chronic) anxiety (rho=0.30, p=0.07) but not state (acute) anxiety (rho=0.23, p=0.16). These preliminary findings suggest that higher anxiety levels are associated with elevated inflammation in persons with obesity beyond that attributable to higher BMI, and that trait anxiety may be more relevant to a pro‐inflammatory state than state anxiety. Further study is warranted to assess whether elevated inflammation in persons with anxiety and obesity represents a potential therapeutic target to mitigate the attendant increased CVD risk.Support or Funding InformationNIH T32 HL07121, AHA13SDG143400012, NIH P01 HL014388, NIH CTSA U54TR001356.
Decrease in Erythrocyte Deformability Promotes the Cell Accumulation near the Vessel Wall in Small Arterioles
Authors: NAMGUNG BUMSEOK , JU MEONGKEUN , NG YAN CHENG , KIM SANGHO 
Published: November 2023

This study demonstrated that the deformability‐impaired red blood cells (RBCs) preferentially accumulate near the vessel walls in arterioles in vivo. Chemically hardened RBCs (hRBCs) with fluorescent labeling from the donor rat were infused into the recipient rat circulatory system while maintaining the total blood volume. Fluorescent imaging analysis was performed to quantify the radial (R) distribution of the labeled hRBCs in small arterioles (~76 μm of diameter). In vivo experimental results showed that majority of the hRBCs (65%) were accumulated near the vessel wall (0.7R–0.9R). This near‐wall accumulation of hRBCs partly contributed to the decrease in the mean cell‐free layer width, and significantly increased the variation of cell‐free layer width (P < 0.05). Dynamic particle simulation by modeling individual RBCs was in agreement with the in vivo experiments by predicting that the hRBCs exhibit relatively weakened tank‐treading motion as compared with normal RBCs. Consequently, this leads to an attenuation in the inward migration of the cells toward the flow center. Our findings conclusively proposed that the preferential near‐wall accumulation of hRBCs in vivo could be attributed by the attenuated dispersion of hRBCs with reduced tank‐treading motion once they entered into the near‐wall zone. In addition, frequent sudden changes of lateral displacement of hRBCs while passing through multiple bifurcations partly contributed to their near‐wall accumulation despite the relatively shorter cell travel distance in vivo.Support or Funding InformationThis work was supported by National Medical Research Council (NMRC)/Cooperative Basic Research Grant (CBRG) No./0078/2014
Remote Control of Intracerebral Arteriole Diameter by Capillary TRPV4 and TRPV3 Channels
Authors: Dabertrand Fabrice , Harraz Osama F , Longden Thomas A , Brayden Joseph E , Nelson Mark T 
Published: November 2023

Brain parenchymal arterioles (PAs) terminate to from a dense network of hundreds of miles of capillaries, which are in close apposition to all neurons. Capillary endothelial cells (cECs) are therefore ideally positioned to detect and respond to local neuronal activity. Using a novel intact ex vivo preparation of pressurized PAs and capillaries from mouse, we revealed that application of the postulated neurovascular coupling agent prostaglandin E2 (PGE2‐1μM) onto capillaries triggered an upstream arteriolar vasodilation (38.6%). We then investigated the hypothesis that activation of EP1 receptors (Gq protein‐coupled PGE2 receptor) in the cECs initiates a retrograde Ca2+ signal mediated by transient receptor potential vanilloid (TRPV) cation channels. Selective capillary stimulation with TRPV4 (GSK1016790A‐1 μM) or TRPV3 (Carvacrol‐10 μM) agonists induced upstream PAs dilation (37.9% and 26.2% respectively). Patch clamp electrophysiology performed on acutely isolated cECs from mouse brain confirmed the presence of both TRP channels (TRPV4: 160.3±26.2 pA/pF at +100 mV; and TRPV3: 14.9±1.7 pA/pF at +100 mV). The TRPV4 antagonist HC‐067047 (1 μM) abolished GSK1016790A‐induced currents and upstream arteriolar dilation, while carvacrol‐induced responses were absent in TRPV3 knock out animals, further supporting the role played by both channels in the capillary to arteriole signaling. Finally, using an adeno‐associated virus approach, we transfected cECs with fluorescent Ca2+ indicator protein GCaMP6f and recorded TRPV4 and TRPV3 channel‐dependent propagating Ca2+ signals within cECs of the aforementioned pressurized ex vivo preparation. We have previously shown that activation of cEC KIR2.1 channels by external K+ initiates a propagated, regenerative hyperpolarization causing upstream arteriolar dilation, which promotes rapid hyperaemia at the site of the K+ increase. Here we present data supporting the presence of a Ca2+ signaling route, acting in parallel with the electrical pathway, that communicates activation of capillary TRPV4 and TRPV3 channels to dilate upstream PAs. In this model, capillary GqPCR activation would reinforce and sustain electrical signals by providing an additional level of spatial and temporal control over cerebral blood flow.Support or Funding InformationSupported by the NIH (R01HL121706, PO1HL‐095488, R37‐DK‐053832; MTN), the Totman Medical Research Trust (MTN), the Fondation Leducq (MTN), the AHA (14POST20480144; TAL), and the United Leukodystrophy Foundation (FD).
Microfluidics‐based side view flow chamber reveals tether‐to‐sling transition in rolling neutrophils
Authors: Marki Alex , Gutierrez Edgar , Zbigniew Mikulski , Groisman Alex , Ley Klaus 
Published: November 2023

Neutrophils rolling at high shear stress (above 6 dyn/cm2) form tethers in the rear and slings in front. Here, we developed a novel photo‐lithographically fabricated, PDMS‐based side‐view flow chamber to dynamically visualize tether and sling formation. Fluorescently membrane‐labeled mouse neutrophils rolled on P‐selectin substrate at 10 dyn/cm2. Most rolling cells formed 5 tethers that were 2–30 μm long. Breaking of a single tether caused a reproducible forward microjump of the cell, showing that the tether was load‐bearing. About 15% of all tether‐breaking events resulted in slings. The tether‐to‐sling transition was fast (<100 ms) with no visible material extending above the rolling cell, suggesting a very low bending modulus of the tether. The sling extended downstream in front of the rolling cell at a downward angle of 6°, without touching the flow chamber for 3.19±0.78(SEM) sec. These new observations explain how slings form from tethers and provide unexpected insight into their biomechanical properties.Support or Funding InformationThis project was supported by the P01 HL078784 grant of Klaus Ley.
The Membrane Lipid Composition Regulates The Activity of Talin
Authors: Ye Xin , McLean Mark A , Sligar Stephen G 
Published: November 2023

Integrins plays a central role in the dynamics of cell‐cell and cell to extra‐cellular matrix interactions and signaling. A key step in the activation of integrin receptors is the binding of the cytoplasmic domain of integrin subunits by talin. This interaction leads to separation of the integrin transmembrane domains and significant conformational changes in the extracellular domains, resulting in a dramatic increase in integrin's affinity for ligands. Talin is a 470 kDa adapter protein that consists of a N‐terminal head domain (THD) and a C‐terminal rod domain. THD is homologous to to the domain found in band 4.1/ezrin/radixin/moesin family of proteins (FERM domain) with uncanonical linear arrangement of F0–F3 domains. A second mechanism in the regulation of integrin activation is directly related to the fact that full‐length talin adopts an auto‐inhibited conformation. In the cytosol, the rod domain binds THD, preventing talin interactions with the membrane surface and the integrin cytoplasmic domain. The membrane bilayer also plays a critical role in the talin ‐integrin interaction, where anionic lipids are required for proper interaction, yet a detailed picture of the interplay between talin and the membrane has remained elusive. We describe a new fluorescence based assay for probing talin – membrane interactions with Nanodisc bilayers of controlled composition. We show that recruitment of THD to the membrane surface is governed by the absolute charge. Measurement of the donor‐acceptor distances reveals that anionic lipids promote a conformational change in the THD favoring a direct interaction of the F3 domain with the phospholipid bilayer. The magnitude of this conformational change is regulated by the identity of the phospholipid headgroup with phosphatidylinositides (e.g. PI4P and PIP2) promoting the largest conformational motions. In addition, the binding of THD to bilayers containing PIP2 is insensitive to the presence of the inhibitory segments of the talin rod domain, while the association of THD to other tested anionic lipid bilayers are strongly inhibited by purified talin rod domains. Furthermore, we have mapped the activation to the interaction of PIP2 with the F2–F3 domain of the THD. Thus, we show that PIP2 plays a central role in the converting talin to a conformation optimized for interactions with integrin cytoplasmic tails and regulation of the auto‐inhibited form of talin, which are essential for integrin inside‐out activation.Support or Funding InformationSupported by NIH grant GM101048.
Neuroanatomy Education: Evaluating Methods Of Delivery On Student Opinions And Academic Performance
Authors: Bergen Hugo , Longo Alison , Peeler Jason 
Published: November 2023

INTRODUCTIONMedical schools have traditionally used a dissection‐based approach for educating students in neuroanatomy. There is a trend towards increased use of prosected specimens, models, and 3‐D imaging materials as learning resources. It is not known which method constitutes the most effective way to teach students a basic understanding of human neuroanatomy. The purpose of this study was to examine whether the method of educational delivery influences student perceptions about learning anatomy, as well as performance on a practical exam.METHODSUndergraduate students from the same medical school were compared. One cohort was taught using a method that involved some dissection of brain specimens while the the second cohort was taught using a method of delivery that employed more prosected specimens. Contact hours for both groups were similar. A standardized educational survey was used to collect information regarding student perceptions and evaluate 6 different methods of delivery. This data was compared against student performance on neuroanatomy practical exams.SUMMARYSeventy students (dissection=40, prosection=30) completed the survey. Survey results revealed that teaching that used clinical cases was the most effective approach for relating anatomical structure to function, while the use of medical imaging was the most effective approach for instilling anatomical knowledge. When comparing the performance of students on the lab practical exam, the dissection group outperformed the prosection group (mean=83% vs 72%). The dissection group also outperformed the prosection group on exam questions that were given to both groups (mean=80% vs 76%).CONCLUSIONSData suggest that student perceptions and academic performance are influenced by the method of delivery, and that medical imaging and case based scenarios enhance the learning environment. The results will be used to guide the selection of delivery method in future neuroanatomy curriculum.Support or Funding InformationFunding provided by the Teaching and Learning Enhancement Fund of the University of Manitoba.