bluuebunny/crossref_metadata_2025 huggingface dataset:
Serum-derived bovine immunoglobulin/protein isolate binds to various opportunistic microbes along with associated virulence factors
Authors: Rose Alexis , Warner Christopher
Published: May 2023

The gut microbiome consists of a complex population of bacteria, fungi, and viruses that aid the host in various physiological functions. When the microbiota is imbalanced, known as dysbiosis, symbiotic microbes can become opportunistic and excrete virulence factors that decrease intestinal barrier function, causing chronic inflammation that leads to disease. Therefore, maintaining gut microbiome balance is critical to overall health. Endogenous immunoglobulins play a positive role in gut homeostasis and immunoglobulin supplements can assist the body with microbiome maintenance. Serum-derived bovine immunoglobulin/protein isolate (SBI), a spray-dried protein powder enriched in immunoglobulins (IgG, IgA, IgM), is clinically proven to help manage loose and frequent stools associated with gastrointestinal enteropathies. A previous study used an in vitro cell culture model to show that SBI binds and neutralizes pattern-associated molecular patterns by steric/immune exclusion mechanisms. The goal of our study is to expand the list of antigens to which SBI binds. We hypothesize the IgG in SBI binds additional opportunistic microbes found in the gut and their associated virulence factors. Heliobacter pylori ( H. pylori), Shigella dysenteriae, Escherichia coli ( E. coli), and Candida albicans ( C. albicans) are common microbes associated with human gastroenteropathies. Therefore, we initially tested the binding of SBI to H. pylori lysate, H. pylori cytotoxicity-associated immunodominant antigen (CagA), Shiga toxin type-1 (Stx1), E. coli cytolethal distending toxin (CDT), C. albicans lysate, and C. albicans agglutinin-like protein 3 (Als3) by a dot blot method. SBI demonstrated binding to all antigens except the H. pylori lysate. To validate specificity of IgG, further binding studies were completed using a modified ELISA. The absorbance of IgG bound to immobilized antigens increased proportionally to SBI concentration (CagA R2=0.98, Stx1 R2=0.97, CDT subunit A R2=0.99, CDT subunit C R2=0.99, C. albicans lysate R2=0.99, and Als3 R2=0.99). Control experiments verified effective blocking, non-specific binding, and functionality (denatured SBI), as no significant absorbance was measured for any antigen tested. Together, the dot blot and modified ELISA showed the IgG in SBI was found to bind to a variety of opportunistic microbes and their associated virulence factors, including CagA, Stx1, CDT subunit A, CDT subunit C, C. albicans lysate, and Als3. Future work will examine if IgG binding can promote gut microbiome balance.

Proliant Health and Biologicals

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Hypothalamic CRH neurons contribute to elevated sympathetic outflow in primary hypertension
Authors: Zhang Hua , Li Depei
Published: May 2023

The corticotrophin-releasing hormone (CRH) is a neuropeptide that critically regulates neuroendocrine and automatic function, which are key two components of stress responses. Hypertension is associated with high stress response and CRH mRNA levels in the hypothalamus and the number of CRH-expression neurons in the hypothalamus are significantly increased in the paraventricular nucleus (PVN) of the hypothalamus in primary hypertension patients. We determined if CRH-expressing neurons in the PVN (CRHPVN) were involved in the pathogenesis of primary hypertension. We found that firing activity of CRHPVN neurons was significantly increased in spontaneously hypertensive rats (SHRs) than those in normotensive control Wistar-Kyoto rats (WKY). Inhibitory light-sensitive channel soma-targeted Guillardia theta anion-conducting channelrhodopsins (stGtACR2s) or excitatory light-sensitive channel ChR2s were CRH-Cre dependently expressed on CRHPVN neurons. Optical inhibition of CRHPVN neurons in SHRs significantly decreased blood pressure and renal sympathetic nerve discharge (RSND) in anesthetized SHRs and blood pressure measured by telemetry approach in conscious SHRs. In WKY rats, inhibition of CRHPVN neurons induced smaller decreases in blood pressure and RSND than those in SHRs. On the other hand, optical stimulation of CRHPVN neurons significantly increased the blood pressure in conscious WKY rats, RSND and blood pressure in anesthetized WKY rats. In brain slice from SHRs, we found that optical inhibition of CRHPVN neurons suppressed the firing activity of RVLM-projecting PVN neurons, an effect was abolished by bath application of CRH receptor antagonist astressin. Optical stimulation of CRHPVN neurons in brain slices from WKY rats increased the firing activity of RVLM-projecting PVN neurons, which was blocked by bath application of astressin. Moreover, selective ablation of CRHPVN neurons with FLEx-Casp3 plus CRH-Cre decreased blood pressure in adult SHRs and suppressed hypertension development in young SHRs. In addition, microinjection of CRHR2 specific antagonist, antisauvagine-30 (TFA) into the nucleus tractus solitarii (nTS) induced the same degree of depressor responses in WKY rats and SHRs. These results suggest that the CRHPVN neurons play a pivotal role in regulating sympathetic outflow and blood pressure in hypertension through CRH receptors on the RVLM-projecting PVN neurons.

Supported by grants from National Institutes of Health (HL139523, HL142133, and HL159157).

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Neonatal intermittent hypoxia-dependent oxidative stress prevents NMDAr subunit remodeling during the critical period producing deficits in synaptic plasticity and spatial memory during adulthood
Authors: Arias-Cavieres Alejandra , Garcia Alfredo J
Published: May 2023

Early postnatal life represents a critical window of brain development that sets the foundation for neurophysiology later in adulthood. Apneas of Prematurity (AoP) is clinical condition that can emerge in neonates born less than 34 weeks and is hypothesized to have long-lasting impact on neurocognition. Untreated AoP produces periodic cessations in breathing leading to neonatal intermittent hypoxia (nIH). The objective of this study is to investigate how nIH impacts NMDAr-dependent synaptic plasticity during and following the critical period of development. To test this, neonatal mice (P4-5) were exposed to ten days of nIH. Biochemical analyses immediately following nIH, revealed that nIH caused oxidative stress corresponding with a greater GluN2B:GluN2A subunit ratio in the hippocampus. These effects were accompanied by a reduced contribution of GluN2A to LTP. Administration of the antioxidant MnTMPyP during nIH prevented these changes. In adult mice, six weeks after exposure to nIH, deficits in behavioral performance in spatial memory tasks were evident. These neurocognitive changes, correlated with a persistent increase in the GluN2B:GluN2A ratio and dysregulated LTP in the adult hippocampus. Administration of MnTMPyP, following nIH was not effective in mitigating the effects observed during adulthood. Our findings suggest that a narrow interventional window exists for mitigating oxidative stress that drive nIH‑dependent changes in hippocampal physiology and spatial memory during adulthood. This work was supported by NIH: R01NS107421

This work was supported by NIH: R01NS107421

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
3D hyoid and tongue kinematics reveal mechanism of tongue base retraction during swallowing in Didelphis virginiana
Authors: Li Peishu , Gidmark Nicholas , Luo Zhe-Xi , Callum Ross
Published: May 2023

In anthropoid primates, tongue base retraction (TBR) is a key event for airway protection and bolus propulsion during swallowing. In macaques, hyoid protraction and elevation during swallowing reduce the oral volume and squeeze the tongue base to retract. This novel hyoid-powered hydraulic TBR mechanism implies that the morphology and position of the hyoid are functionally relevant for TBR performance. However, macaque’s highly derived craniofacial and hyoid morphology precludes inference on the evolutionary history and driving mechanism of TBR across mammal phylogeny at large. Here we use biplanar videoradiography and the XROMM workflow to infer TBR mechanism in Didelphis virginiana through high-resolution 3D hyolingual kinematics. Similar to macaques, Didelphis has an incomplete hyoid cornu, which would enable a large hyoid range of motion that facilitates oral volume reduction. Unlike macaques, Didelphis hyoid has a more posteriorly resting hyoid position. We predict that TBR will occur in Didelphis through a similar hyoid-powered hydraulic mechanism. We find Didelphis deploys TBR during the first opening (O1) phase (liquid) or slow-open phase (solid) of jaw cycle with retraction and elevation of midline posterior tongue markers. Minimal retraction occurs in lateral tongue markers where extrinsic lingual muscles insert. The tongue base and posterior tongue are lengthening, narrowing and increasing in height during TBR, consistent with predictions based on muscular hydrostat model. The tongue base was not isovolumetric during TBR, but the volume change was orders of magnitude smaller than that observed in macaques. Hyoid protraction and elevation occur before and continue throughout TBR, which strongly suggest concurrent reduction of oral volume as well. Our preliminary data suggest the TBR mechanism in opossums may differ in important ways from that utilized by macaques, where opossums could employ a combination of hydrostatic deformation and hydraulic mechanism to drive retraction of tongue base. We provide novel insights into the conservation of TBR across therian mammals and extend our understanding on the form-function relationships between the hyolingual apparatus and swallowing biomechanics.

Hinds Fund, University of Chicago

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Neonatal stress favors age related rise in sleep apnea and metabolic comorbidity in female rats
Authors: Guay Loralie Mei , Ambrozio Marques Danuzia , Fournier Stéphanie , Kinkead Richard
Published: May 2023

Introduction: In women, the natural loss of ovarian function during menopause is associated with an increase in the number of cases of sleep apnea and its comorbidities, such as hypertension and obesity. However, only a subpopulation of women is affected by these disorders, a trajectory that is misunderstood. We know that stress and childhood adversity are linked with a sex specific increase in disease susceptibility in adults. In mammals, exposure to neonatal maternal separation (NMS) is an established pre-clinical model to address the consequences of early life stress. Therefore, we hypothesized that NMS increases respiratory control disorder and favors obesity in 1-year old female rats. Methodology: Rat pups were either undisturbed (CTRL) or subjected to NMS during which pups were placed in a temperature-controlled incubator 3h/day from postnatal day 3 to 12. At 60 weeks of age, we measured apnea frequency during sleep and chemoreflex response to hypoxia (10% O2; 40s) or hypercapnia (5% CO2; 10 minutes) using a whole-body plethysmography system. We also measured body weight and body length (to calculate the body mass index (BMI – g/cm2)), % of fat (using a magnetic resonance equipment – BRUKER) and leptin levels in the plasma (by Luminex® technology, a bead-based immunoassay). Results: Apnea frequency of NMS females was 20% higher than CTRL; the ventilatory responses to hypoxia and hypercapnia were also significantly greater (30% and 94% respectively). The BMI of NMS was 18% higher than CTRL and greater than the threshold for obesity. Additionally, those animals presented 5% more fat in their body composition, 5% less lean tissue and the same % of fluids. As for leptin, the mean values were similar but the variation in blood levels was 34% higher in NMS than in CTRL. Conclusions: Age-related loss in ovarian function reveals the latent effects of early life stress on respiratory control. By predisposing to obesity and interfering with leptin signaling, NMS also favors metabolic disturbance commonly observed in ageing women. These data suggest that stress is an important factor in the development of sleep apnea and related co-morbidities in a subpopulation of menopausal women.

DAM is supported by the FRQ-S (268346) and the Programme de complément de bourse from RSRQ (2021-22). This research is supported by the Canadian Institutes of Health Research (RK).

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
A Novel Oxygen Cocktail for Renal Protection and Survival Extension During Prolonged Hemorrhagic Shock
Authors: Xiang Lusha
Published: May 2023

The current study aimed to develop a novel oxygen cocktail (XC) in order to decrease hemorrhagic shock-induced complications including renal injury, acidosis, hyperlactatemia, hyperkalemia, and mortality when on-time resuscitation is unavailable. XC was designed by combining polyethylene glycol (PEG) and transcrocetinate (TSC) to improve both oxygen delivery and diffusion under hypotensive condition. Using an established model of prolonged hemorrhagic shock and acute kidney injury (AKI), we hypothesized that early XC treatment would improve compensatory mean arterial pressure (MAP), renal oxygen levels, and decrease shock related acidosis, hyperlactatemia, hyperkalemia, AKI, and mortality. Male rats were randomized into 4 groups based on treatment: saline (vehicle), PEG, TSC, XC (n = 7-8 for each group). Trauma was induced in anesthetized rats with muscle injury and fibula fracture, followed by pressure-controlled hemorrhagic shock (MAP = 55 mmHg) for 45 minutes. Rats then received an intravenous injection (0.3ml/kg) of saline, PEG, TSC, or XC. MAP, skeletal muscle perfusion and oxygen partial pressure (PO2), renal hemodynamics, glomerular filtration rate (GFR), urinary flow, and mortality were monitored for another 2 hours. XC rapidly increased MAP, renal blood flow, oxygen delivery, GFR (saline 0.05 ± 0.01, TSC 0.12 ± 0.05, PEG 0.48 ± 0.10, XC 0.47 ± 0.05, ml/min/100g,), and urinary flow (saline < 0.1, TSC < 0.1, PEG 8.42 ± 2.82, XC 5.65 ± 0.88, ml/min), and decreased hyperlactatemia and mortality (saline 100%, TSC 75%, PEG 12%, XC 0%). The microcirculatory perfusion in skeletal muscle was similar between XC and PEG groups. However, the increase in PO2 was much more profound and prolonged in XC compared to PEG. Saline or TSC injection had no effect on these profiles. Our data suggest that XC is most effective in maintaining renal oxygen levels under hypovolemic conditions despite a lack of resuscitation. Due to its rapid- and long-acting beneficial effects on organ oxygenation, XC may be a potential option to protect organ function and extend survival during prolonged hemorrhagic shock when timely resuscitation with blood and blood products is unavailable.

This study was funded by US Army Medical Research and Development Command.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Bacterial targeting of the P-glycoprotein to reduce intestinal inflammation in ulcerative colitis
Authors: Sallis Benjamin , Foley Sage , Bucci Vanni , Ward Doyle , Houghton JeanMarie , McCormick Beth
Published: May 2023

Ulcerative colitis (UC) is a devastating chronic disease characterized by aberrant colonic inflammation and intestinal dysbiosis. The pathognomonic ulceration as well as intestinal epithelial damage is driven by excess luminal infiltration and activation of neutrophils. Recently our group discovered a system of lipid mediators regulating transmigration of neutrophils from the colonic lamina propria across the epithelial barrier. During homeostasis the multidrug resistance efflux pump p-glycoprotien (P-gp) maintains a gradient of endocannabinoids, which limits neutrophil transmigration. During inflammation however, P-gp is downregulated and Multidrug resistance-associated protein 2 (MRP2), which secretes the neutrophil chemoattractant hepoxilin A3 is upregulated, promoting luminal infiltration of neutrophils. In ulcerative colitis P-gp is significantly downregulated, resulting in the excess luminal accumulation of neutrophils found in ulcer bases. We discovered that the balance of these multidrug resistant efflux pumps is dependent on the microbiome and its secreted metabolites, which is significantly altered in UC. Consequently, we are designing a consortium of bacteria to optimize the expression of P-gp on the host epithelium and thus restrain neutrophil transmigration in UC.Using antibiotic stratification experiments and fecal xenograft models we have identified specific bacterial species that increase P-gp expression, and thus likely restrain neutrophil transmigration. Thus far we have validated the role of 15 candidate bacteria and 78 bacterial metabolites in regulating P-gp expression and function either directly or through interactions with other bacterial species. Leveraging this understanding of microbial regulation of host efflux pumps as well as in-vivo population dynamics data we are developing an algorithm to predict the P-gp induction ability of all possible combinations of candidate microbe. Using this algorithm we will design P-gp high, mid, and low inducing consortia, to study the role of these populations on intestinal inflammation using murine models of ulcerative colitis. The development of such consortia has wide ranging implications for research and clinical practice alike from facilitating further study of the underlying inter-microbial networks regulating key host defense systems in the intestine to the development of a probiotic with the potential to limit colonic neutrophil infiltration in patients with UC.

This work is supported by R01DK125407, T32AI132152, and F30DK134110 by National Institutes of Health.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
LRRC8A Anion Channel Associates with Myosin Phosphatase Rho Interacting Protein (MPRIP) to Regulate Vascular Function
Authors: Choi Hyehun , Nguyen Hong N , Lamb Fred
Published: May 2023

Volume-regulated anion channels (VRACs) are activated by tumor necrosis factor alpha (TNFα) and angiotensin II. VRACs are composed of Leucine Rich Repeat Containing 8 (LRRC8) family proteins (LRRC8A, B, C, D and E) and LRRC8A is required for all VRACs. LRRC8A associates with NADPH oxidase 1 (Nox1) and modulates production of extracellular superoxide in vascular smooth muscle cells (VSMCs). We investigated vascular reactivity in mesenteric arteries from wild type (WT) and smooth muscle-specific LRRC8A knockout (KO) mice. KO vessels displayed enhanced responsiveness to multiple vasodilator agents; acetylcholine, sodium nitroprusside, PKA (forskolin) or PKG (BAY60-2770) activators and a Rho kinase inhibitor (Y-27632), compared to WT. This was associated with decreased RhoA activity and reduced ROCK-dependent MYPT1 phosphorylation at T853. To explore the mechanism of enhanced relaxation we immunoprecipitated LRRC8A-associated proteins from WT and KO VSMCs and analyzed these by mass spectroscopy. Myosin Phosphatase Rho-Interacting protein (MPRIP) was identified only in WT lysates. MPRIP is a scaffolding protein that binds to RhoA, MYPT1, and actin and regulates activity of the myosin light chain phosphatase complex. Association of LRRC8A and MPRIP was confirmed using IP/western blot, proximity ligation assay (PLA) and immunohistochemistry. LRRC8A binds to the second plextrin homology domain of MPRIP. Knockdown of MPRIP (siRNA) increased protein expression of LRRC8A in cultured VSMCs. To explore the relationship between Nox1/LRRC8A, superoxide and intracellular redox signaling events sulfenylation of MPRIP cysteine residues (-SOH) was quantified using DCP-Bio1 (a biotin-labeled dimedone derivative) pulldown with streptavidin beads and western blotting. Sulfenylation was significantly increased 3 min following TNFα stimulation (2.3 fold, n = 3, p < 0.05). It remains to be determined how this impacts association of MPRIP with its four binding partners. Disruption of interaction between Nox1/LRRC8A and MPRIP/RhoA/MYPT1/actin may underly enhanced vasodilation in VSMC-specific LRRC8A null blood vessels. This multi-protein complex provides a potential mechanism by which oxidants produced by Nox1 impact vasomotor function, linking inflammation to increased vascular reactivity and hypertension.

NIGMS (5R35GM138191-02), NIDDK (1R01DK132948-01), NHLBI (1R01HL160975-01A1)

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Role of the Circadian Clock System in Trans-sulfuration Pathway and Tissue Remodeling
Authors: Tyagi Suresh , Tyagi Suresh , Sathnur Sathnur , Sen Utpal , Akinterinwa Oluwaseun , Zheng Yuting , Mokshagundam Sriprakash , Singh Mahavir
Published: May 2023

Previous studies from our laboratory revealed that the gaseous molecule; hydrogen sulfide (H2S), a metabolic product of epigenetics which involves trans-sulfuration pathway for ensuring the metabolism and clearance of homocysteine (Hcy) from the body, helped mitigate the skeletal muscle’s pathological remodeling. Although the master circadian clock regulator that is known as the b rain and m uscle a ryl hydrocarbon receptor nuclear translocator l ike protein 1 (i.e., BMAL1) is intimately associated with S-adenosylhomocysteine hydrolase (SAHH) and Hcy metabolism but how trans-sulfuration pathway is influenced by the circadian clock system remains unexplored. We hypothesize that potential alterations in the functioning of circadian clock during sleep and wake cycle affect the skeletal muscle’s biology. To test this hypothesis, we measured serum matrix metalloproteinases (MMPs) activities using gelatin gels for analyzing the MMP-2 and MMP-9 activities. Further, employing the casein gels we also studied MMP-13 that is known to be influenced by the growth arrest and DNA damage-45 (GADD45) protein during sleep and wake cycle. The wild type (WT) and cystathionine β synthase deficient (CBS-/+) mice strains were treated with H2S and subjected for measurement of trans-sulfuration factors from their skeletal muscle tissues. The results suggested highly robust activation of MMPs activities in the wake mice versus sleep mice that appears somewhat akin to that of the “ 1-carbon metabolic dysregulation” which takes place during remodeling of extracellular matrix (ECM) in muscular dystrophy affected tissues. Interestingly, the levels of trans-sulphuration factors such as CBS, cystathionine γ lyase (CSE), methyl tetrahydrofolate reductase (MTHFR), phosphatidylethanolamine N-methyltransferase (PEMT), and Hcy-protein bound paraoxonase 1 (PON1) were attenuated in the CBS-/+ mice. However, treatment with H2S mitigated the attenuation occurring in the trans-sulfuration pathway. In addition, levels of mitochondrial peroxisome proliferator-activated receptor-gamma coactivator 1-α (PGC 1-α) and mitofusin-2 (MFN-2) were significantly improved by H2S intervention. Our findings suggest participation of the circadian clock system in trans-sulfuration pathway that affect the skeletal muscle remodeling and mitochondrial regeneration.

HL-139047, DK116591 and AR-71789

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
KCC3a is regulated by HCO3- independently of pendrin
Authors: Ferdaus Mohammed , Wall Susan , Delpire Eric
Published: May 2023

The inactive form of the Cl-/HCO3 exchanger - pendrin in humans results in Pendred syndrome. With dietary Na+ restriction, patients with Pendred syndrome experience significant metabolic alkalosis, hypokalemia, and lower blood pressure. K+ loss is often observed with metabolic alkalemia. K+ loss is also a significant danger for patients, especially those who are taking diuretics, have hypokalemia, or have electrolyte abnormalities. Recently, we discovered the K-Cl cotransporter-3 isoform-a (KCC3a) in intercalated cells that express pendrin. We demonstrated that loss of KCC3a decreased pendrin abundance and alkalemia increased KCC3a abundance. Our findings also suggest that Cl-, secreted by KCC3a, is recycled by pendrin, acting as a driving force for pendrin function. Based on our findings we hypothesized in this follow-up study that KCC3a is regulated by HCO3- independently of pendrin. To test our hypothesis, we examined the KCC3a abundance in pendrin knockout (KO) mice fed a Na+, K+ and Cl- deficient diet that caused K+ loss. We evaluated how the abundance of KCC3a in mice responded to HCO3- challenge with and without high salt diet. Losartan, an angiotensin II receptor type 1 antagonist, was administered to mice to explore the role of angiotensin II (Ang-II) in KCC3a-regulating signaling. To determine the role of HCO3- and aldosterone in KCC3a signaling, we also looked at how KCC3a levels changed to KCl, or K-citrate loading.On a Na+, K+, and Cl- deficient diet, KCC3a abundance was greater in pendrin-KO mice, indicating that this was the cause of the observed K+ loss. In a HCO3- challenge experiment, KCC3a abundance increased with HCO3- both with and without high salt and Losartan did not change KCC3a level, demonstrating an independent response from Ang-II. With K-citrate challenges but not with KCl loading, KCC3a abundance increased, indicating an aldosterone independent and HCO3- mediated response as citrate is metabolized to HCO3-. We also show the mouse cortical collecting duct M-1 cells express KCC3a and that expression is markedly enhanced in the presence of bicarbonate, but not alkaline pH. Taken together, our findings suggest that HCO3- is the primary signaling molecule responsible for increasing KCC3a abundance.Our results demonstrate that HCO3- is the key signaling molecule regulating KCC3a abundance and that, unlike pendrin, the response to increasing KCC3a abundance is not dependent on pendrin.

NIH grants: R01DK093501 and R01DK110375, and by International Network of Excellence Leducq Foundation grant: 17CVD05.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Effects of FOLFOX Chemotherapy Regimen and Exercise on Circulating Factors of Cardiovascular Disease in Mice
Authors: Baumfalk Dryden , Halle Jessica , Carson James , Smuder Ashley
Published: May 2023

Background: Cancer patients treated with FOLFOX are burdened by an array of side effects which can lead to early cessation of treatment. Specifically, FOLFOX is associated with increases in arterial stiffness, LV-stunning/weakness, both of which can lead to acute or chronic risk of developing heart failure and cardiovascular disease. To increase cardiovascular fitness and prevent FOLFOX cardiotoxicity exercise interventions have been proposed; however, a dearth of information exists on the timing and type of exercise that should be performed. Therefore, the purpose of this study was to investigate FOLFOX-induced alterations in circulating markers associated with cardiovascular damage 4-weeks post cessation of treatment, and to determine whether exercise can be utilized to mitigate increases in risk associated markers of cardiovascular disease. Methods: Male C57BL/6J mice (3 months) received 4 cycles (1 injection every 2 weeks) of FOLFOX (5-fluorouracil 30mg/kg, oxaliplatin 6mg/kg, leucovorin 90mg/kg), and were randomized to subgroups of sedentary (FOX, n=12), exercise trained (EXFOX, n=10), or PBS shams (CON n=11, EXCON n=9). Exercise training consisted of 14 sessions of treadmill exercise (18m/min, 5%grade, 15 minutes) during weeks 2-4 of the recovery period. Following completion of the treatment/exercise training, mice were sacrificed after a 12h overnight fast and a minimum of 48h after the last bout of exercise. Circulating markers were evaluated using Luminex Magpix® multiplex analyzer (MILLIPLEX Mouse CVD1&CVD2 Bead Panel, Millipore Sigma, Burlington, MA, USA). Results: There was a significant effect of FOLFOX (p<0.05) for soluble endothelium selectin (sE-selectin), soluble platelet selectin (sP-selectin) and thrombomodulin. Significant effects of exercise (p<0.05) were found for soluble intercellular adhesion molecule-1 (sICAM-1), platelet endothelial cell adhesion molecule-1 (Pecam-1) and thrombomodulin. Conclusion: This preliminary investigation suggests there are systemic alterations in markers associated with cardiovascular disease following FOLFOX regimen occurring weeks after cessation of treatment. Low intensity exercise was unable to show any benefits in terms of preventing increases in these cardiovascular disease risk markers. These results promote further investigation into the impact these alterations may have on cardiac or vascular tissue following FOLFOX treatment.

National Cancer Institue: R21-CA231131 & National Institutes of Health: R01HL14458

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Using a Stepped Framework of Student-led Laboratories to Help Teach Science Communication in Physiology
Authors: Petzold Andy
Published: May 2023

Instilling science communication skills within an undergraduate physiology education is paramount to success within the sciences. Failure to be successful in communicating science can lead to a variety of difficulties at both the professional level and while communicating effectively to a broader audience. Unfortunately, these misgivings that derive from science communication issues can have wide-sweeping, real-world consequences ranging from misrepresentation or misinterpretation of scientific findings, to misunderstanding regarding the scientific process to outright scientific misinformation. How to communicate science is an important skill that must be gained through a combination of practice and teaching. Introducing students to the basics of science communication within a single course through laboratory assignments can be used as a method of teaching varied communication methods. We have developed a framework, that has been used in several different physiology courses, to teach the basics of science communication alongside instruction surrounding the scientific method and basic laboratory techniques. Specifically, we have used a stepped approach to laboratory experiments that are driven by student interest and coupled this with three styles of science communication – a poster, a talk, and a paper. This stepped framework begins with a guided lab that allows students to test their own hypothesis with limitations and ends with a largely freeform, student-led experiment at the end of the semester. Students felt they were more engaged with the curricular material and had better learning outcomes compared to previous methods of instruction. This basic framework could provide a mechanism for instructing laboratory techniques, “real-world” science and science communication methods while keeping students engaged and excited about the coursework.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
PRDM16 Deficiency in Vascular Smooth Muscle Cells Aggravates Abdominal Aortic Aneurysm
Authors: Chang Lin , Wang Zhenguo , Mu Wenjuan , Zhao Guizhen , Guo Yanhong , Zhang Jifeng , Chen Eugene Y
Published: May 2023

Abdominal aortic aneurysm (AAA) is usually asymptomatic until severe complications with high risk of lethality occur, predominantly involving aortic rupture. Currently, no drug-based treatments are available, primarily due to limited understanding of AAA pathogenesis. PR domain-containing protein 16 (PRDM16) is a transcriptional regulator that governs gene expression by cooperating with other transcription factors. It is highly expressed in the aorta, but its functions in the aortic tissue and AAA pathology are largely unknown. In this study, we investigated the roles of PRDM16 in vascular smooth muscle cells (VSMCs). By RNA-seq analysis, we found that VSMCs-specific Prdm16 knockout mice ( Prdm16 SMKO) already showed extensive changes in the expression of genes associated with extracellular matrix (ECM) remodeling and inflammation in the abdominal aorta under normal housing conditions without any pathological stimuli. We found that human AAA lesions displayed decreased PRDM16 expression in the aortic medial layer. Periadventitial elastase application to the suprarenal region of the abdominal aorta aggravated AAA formation in Prdm16 SMKO mice. During AAA development, VSMCs undergo apoptosis because of both intrinsic and environmental changes including inflammation and ECM remodeling. Prdm16 deficiency promoted inflammation and apoptosis in VSMCs. A disintegrin and metalloproteinase 12 (ADAM12) is a gelatinase which can degrade various ECM. We found that ADAM12 is a target of transcriptional repression by PRDM16. Adam12 knockdown reversed VSMC apoptosis induced by Prdm16 deficiency. Our study demonstrated that PRDM16 deficiency in VSMCs promoted ADAM12 expression and aggravates AAA formation, which may provide potential targets for AAA treatment.

This work was partially supported by National Institutes of Health grants HL151524 (L. Chang)

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Improved workflow for analysis of smooth muscle calcium signals from intact arterial preparations
Authors: Boskind Madison , Nelapudi Nikitha , Williamson Grace , Juarez Rucha , Mendez Bobby , Zhang Lubo , Blood Arlin , Wilson Christopher , Wilson Sean
Published: May 2023

Intracellular Ca2+ signals are well regarded for their regulation of cellular processes ranging from myocyte contraction, hormonal secretion, neural transmission, cellular metabolism, transcriptional regulation, and cell proliferation. Measurement of cellular Ca2+ is routinely performed using fluorescent microscopy techniques with biological indicators. Analysis of deterministic signals is relatively straightforward as relevant data can be discriminated based on the timing of cellular responses. However, analysis of stochastic events in complex tissues takes considerable time and effort that often includes visual analysis by trained investigators. The purpose of the current study was to determine if the image analysis workflow could be automated without introducing errors. This evaluation was addressed by re-analyzing a published “gold standard” dataset through visual analysis of Ca2+ signals from recordings made in pulmonary arterial myocytes of en face arterial preparations. We applied a combination of data-driven and statistical approaches with comparisons to our published data to assess the fidelity of the various approaches. Regions of interest with Ca2+ oscillations were detected automatically post-hoc using the LC Pro plug-in for ImageJ. Oscillatory signals were separated based on event durations between 4 and 40 seconds. These data were filtered based on cutoffs obtained from multiple methods and compared to the published manually curated “gold standard” dataset. After filtering, the number of true positives, false positives, and false negatives were calculated through comparisons to the gold standard dataset. Positive predictive value, sensitivity and false discovery rates were calculated. There were very few significant differences between the quality of the events and no systematic biases based on the data curation or filtering techniques. The lack of difference between manual data curation and statistically derived critical cutoff techniques leads us to question the importance of manually curating stochastic Ca2+ event datasets using labor-intensive visual observation techniques.

NIH R01HL155295, R01HL149608

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Glucose Carbon Dots Cross the Blood-Brain Barrier and Preferentially Target Spinal Neurons
Authors: Parikh Komal , Seven Elif , Luca Edward , Mitchell Gordon , LeBlanc Roger , Seven Yasin
Published: May 2023

The spinal cord processes and transmits neural signals controlling sensorimotor functions (e.g., breathing, locomotion, and bladder control). Disorders of the spinal cord, such as spinal cord injury and neurodegenerative diseases, often impair sensory and motor functions, causing morbidity and mortality. Therefore, it is important to develop drug delivery platforms to deliver the therapeutics directly to the spinal cord (availability) and target specific cell populations (specificity). Nanoparticles have been used as effective delivery platforms for drugs. However, whether those nanoparticles can target desired cell types in the spinal cord remains unknown. Here, we hypothesized that glucose-based carbon dots (GluCDs) cross the blood-brain barrier (BBB) and localize to neurons in the spinal cord. To test this hypothesis, we injected Sprague-Dawley rats with GluCD-fluorescein nanoconjugate intravenously. Fluorescein enabled visualization of spinal cord nanoparticle distribution and mimicked a small molecule drug cargo. Four hours post-injection, spinal cords were harvested, fixed in paraformaldehyde overnight, and cryopreserved. Tissues sections (40-μm thickness) were analyzed for cell-type colocalization with GluCD-fluorescein conjugate in the green channel and cell markers in the red channel. We used NeuN (neuronal marker), GFAP (astrocyte marker), and IBA1 (microglial marker) to label different cell types. We quantified colocalization in 3 ways: 1) Percent colocalization with different cell types, 2) 2-dimensional cross-correlation analysis with MATLAB, and 3) Positive/negative classification by 2 independent operators. Colocalization analyses demonstrated that GluCD-fluorescein nanoconjugates crossed the BBB and significantly colocalized with spinal neurons in ventral, intermediate gray, and dorsal regions. ~95% of the GluCD-fluorescein nanoparticles colocalized with neurons, and ~4% colocalized with microglia. There was no colocalization of GluCD-Fluorescein with GFAP-positive astrocytes. Thus, GluCD nanoparticles penetrate the BBB and colocalize with neurons, making them highly novel and promising neuron-specific drug delivery platforms for spinal cord injury and neurodegenerative diseases.

Supported by: NIH R21NS119862-01

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Feasibility of using radiolabeled nitrogen-13 to track nitrogen kinetics in rodents exposed to hyperoxia or hyperbaric pressure.
Authors: Ashworth Edward , Ogawa Ryotaro , Vera David , Lindholm Peter
Published: May 2023

Decompression sickness occurs from tissue supersaturation with nitrogen when pressure is reduced. It limits operational capacity in diving, aviation and extravehicular activity in space. Little is known about organ variability, and why differences exist between individuals. Procedures are based on empirical testing and mathematical modelling, with limited data from actual nitrogen load or diffusivity. Nitrogen has a positron-emitting isotope that can be made in gaseous form (13N2) which can then be monitored spatially and temporally. The feasibility to study nitrogen kinetics was assessed using hyperbaric pressure to increase the partial pressure or pre-breathing oxygen to increase tissue uptake capacity, both of which would expect to cause increased nitrogen uptake. Fifteen female Sprague Dawley rats were divided into air-breathing normobaric (CON), oxygen-breathing, including 1 h pre-breathing (OXY), and air-breathing hyperbaric, compressed to 700 kPa (HB). Breathing gases were supplemented with trace amounts of 13N2 for 30 min, with CON & OXY euthanized at 30 min. HB were decompressed and breathed air/isoflurane without 13N2 for 10-15 minutes before euthanized. Blood, liver, brain, femur (bone) and thigh muscle were analyzed in a gamma counter with the 13N2 counts normalized for organ mass. In liver (p=.026) and brain (p=.018) 13N2 was greater in OXY than both CON and HB. In the femur HB was higher than CON (p=.048). Results suggest that pre‑breathing O2 in OXY removed tissue nitrogen creating a larger gradient for 13N2 uptake. We interpret the limited increase in 13N2 in HB was due to off-gassing in high-perfused tissues during decompression, with the high femur value being due to uptake in HB but slower off-gassing during decompression. Our data suggest that 13N2 can be used to track gas kinetics in a live rodent during physiological conditions endured by humans.

This study was supported by a grant from the Office of Naval Research.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Influence of aerobic exercise on cognitive function in the TgF344-AD model of Alzheimer's disease
Authors: White Zachary , Young Michael , Hall Stephanie
Published: May 2023

Introduction – Exercise therapy is a promising strategy for Alzheimer’s disease (AD) protection although our understanding of exercise-induced neuroprotection remains incomplete. The goal of the present study is to longitudinally characterize the influence of exercise training on changes in cognitive function in both male and female TgF344-AD rats. We hypothesize that cognitive function will be impaired by AD and exercise-training will rescue AD-induced impairments. Methods – Male and female TgF344-AD rats (n=62) began a six-month progressive treadmill training protocol at 12 months of age. Training was conducted 5 days per week and intensity maximized at 24 meters per minute for 60 minutes. Behavioral testing, including Morris Water Maze (spatial learning and memory), Rotarod (motor coordination), and grip strength (muscular strength), was conducted at months (m) 3, 6, 9, 12 (pre-intervention), and 13-18 (post-intervention). Investigators were blind to presence of AD. Differences were identified with Bayesian multivariate linear regression. Results – Memory (latency time, s) was rescued by exercise in female AD rats. Post-intervention, female exercise groups demonstrated improved memory (-0.02 log scale s/m) while sedentary controls declined; no exercise effect was detected in male wild-type (WT) or AD groups. Grip strength is represented relative to body weight (g/g). Post-intervention, average grip strength declined across all groups and declines were greater in AD compared to WT animals (-0.038 vs -0.011 log-transformed g/g per month). Exercise attenuated the age-related declines compared to sedentary controls (0.001 vs -0.0498).The rate of grip strength loss from 13 m to 18 m was one-eighth the rate in female AD exercisers compared to female AD sedentary (-0.009 vs -0.075) while male AD exercisers lost strength at one-fourth the rate compared to male AD sedentary (-0.013 vs -0.054). Conclusions – In the present study the influence of advanced age, AD genotype, and exercise training in the TgF344-AD rat manifested in a sex-specific manner. In females, exercise training ameliorated AD-induced memory deficits and ameliorated age- and AD-induced strength declines to a greater degree than males. Our time-wise characterization of memory and grip strength in the TgF344-AD rat provides valuable reference for future biochemical analysis aimed at elucidating mechanisms of exercise-induced neuroprotection.

R03 AG065970, P20GM113109

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.