bluuebunny/crossref_metadata_2025 huggingface dataset:
Loss-of-STING function by nitro-fatty acids reduces endometriotic lesion formation in a syngeneic model of endometriosis
Authors: Pitts Mareena , Xu Wei , Garcia-Barrio Minerva , Schopfer Francisco , Thompson Winston , Villacorta Luis
Published: May 2023

Endometriosis is a painful, chronic inflammatory disease that impacts fertility and the overall well-being in 10% of reproductive age women. Current therapies include hormonal treatment to induce a hypoestrogenic state, causing serious complications from side effects. STING (Stimulator of Interferon Genes) plays an essential role in innate immunity but also exacerbates inflammation in chronic inflammatory diseases. Recently, STING was found aberrantly upregulated in endometriosis patients. Nitro-fatty acids (NO2-FAs) are bioactive lipids that exert anti-inflammatory and protective roles in preclinical models of inflammation and fibrosis, in part via inhibition of STING. We hypothesized that NO2-FAs protect against STING-dependent endometriosis lesion formation and tested its therapeutic potential using a syngeneic transplant model of endometriosis. Mice expressing green fluorescent protein (EGFP) were treated with Pregnant Mare Serum Gonadotrophin (PMSG) to induce decidualization. Decidualized uterine fragments were transplanted into wild-type (WT) female recipients randomized to receive NO2-FA or vehicle. Endometriosis was allowed to develop for 28 days. In vivo imaging of EGFP donor-derived endometrial lesions demonstrates that NO2-FA administration significantly reduces peritoneal endometriotic lesion formation in female recipients. Furthermore, loss-of-STING function, using STING KO female mice as recipients, demonstrates that STING plays a systemic functional role on endometriosis development. Finally, our studies demonstrate that NO2-FAs inhibit cyclic GMP-AMP Synthase (cGAS)-induced type I interferon signaling in bone-marrow derived macrophages (BMDM) and in the peritoneum of WT female mice but not STING KO mice. In summary, we show that STING is a novel, essential factor contributing to the pathogenesis of endometriosis and that NO2-FA administration may serve as a novel non-hormonal therapy against endometriosis by targeting STING.

This study is funded by the American Physiological Society William Townshend Predoctoral Fellowship (MP), NIMHD U54-MD007602 (WT), R01-HL162294 (MGB) and R01-HL123333 (LV).

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.
Transient changes in endothelial and epithelial cell cytoskeleton and morphology upon olfactory receptor signaling
Authors: Nilon Annabella , Scibek Jacob , Curtis Theresa
Published: May 2023

Olfactory receptors (ORs) are expressed in various non-nasal tissues; however, their physiological roles are largely unknown. ORs are G-protein coupled receptors (GPCRs), and there is a well-established link between different classes of G-proteins and cytoskeletal structure changes affecting cellular morphology that has been unexplored after odorant binding. Thus, the present study was conducted to determine if odorant binding in non-olfactory cells causes cytoskeletal changes that lead to cell morphological changes. To this end, human umbilical vein endothelial cells (HUVECs), which express OR10J5, and human keratinocyte (HaCaT) cells, which express OR2AT4, were used to conduct this study. Using these two different cell lines, it was shown that odorant addition, lyral and Sandalore, respectively, caused a dose-dependent increase in cAMP. Furthermore, HUVECs exposed to lyral exhibited a disassembly of the tubulin-containing microtubules and an increase in cortical actin microfilaments, whereas HaCaT cell exposure to Sandalore exhibited both a disassembly of the tubulin-containing microtubules and cortical actin microfilaments. Even though the endothelial and epithelial cell lines had different cytoskeletal responses to odorant exposure, both exhibited a change in cellular morphology as detected by a decrease in electrical resistance using Electric Cell-substrate Impedance Sensing (ECIS; Applied Biophysics, Inc., Troy, NY). Interestingly, these odorant-induced cytoskeletal and morphological changes occurred rapidly (under 1 hour) but returned to normal after 20 hours, highlighting the complexity of olfactory signaling, which may involve desensitization of the signaling pathway and/or internalization of the odorant receptor. Future experiments will further elucidate the olfactory receptor signaling mechanism in endothelial and epithelial cells so that their physiological role can be fully understood.

Funded by Army Research Office STTR #W911NF-19-P-0014 and W911NF-20-C-0014, the SUNY Cortland Undergraduate Research Council, and Research and Sponsored Programs.

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 small molecule inhibitor of vascular endothelin signaling and hypertension
Authors: Ezewudo Emmanuella , Menon Sreelakshmi , Zerin Farzana , Moniri Nader , Nguyen Tro , Kashikar Rama , Chougule Mahavir , Rahman Taufiq , Hasan Raquibul
Published: May 2023

Augmented endothelin-1 (ET-1) signaling causes profound vasoconstriction, smooth muscle proliferation, endothelial dysfunction, oxidative stress, and vascular inflammation and sensitivity, which are often present in resistant hypertension, salt-sensitive hypertension and hypertension among African Americans. Here, we sought to examine the role of indole-3 acetic acid (IAA) as a novel inhibitor of vascular ET-1 signaling and hypertension. IAA, popularly known as auxin, is the most potent plant growth hormone, which is also produced in the human body via tryptophan metabolism by gut microbiota. Although the role of IAA as a potent plant growth hormone has been characterized, little is known about the biological activity of this compound in humans. Importantly, studies on the role of IAA as a regulator of arterial contractility, vascular inflammation and hypertension remain completely unexplored. Our data demonstrates that IAA inhibits ET-1-evoked vasoconstriction in resistance mesenteric arteries, ROS production in human aortic SMCs, expression of adhesion molecule VCAM-1 on EC surface, leukocyte adhesion, and ECE-1 activity. IAA dose-dependently inhibits the activity of a purified human endothelin converting enzyme-1 (ECE-1) that converts the precursor big ET to its active form ET-1 and is upregulated in hypertension. Consistent with these findings, we show that treatment of Dahl salt-sensitive (DSS) hypertensive rats, a model of augmented ET-1 signaling, with an oral extended-release, in situ gel-based formulation of IAA (IAA-oragel) reduces blood pressure (BP) elevation, suggesting a key role for IAA in BP regulation. Taken together, this study presents a novel inquiry into regulation of ET-1 function by IAA and could identify IAA as the first dual action inhibitor of the ET system.

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 Western Diet Modifies the Activation Profile of Circulating Platelets
Authors: Corken Adam , Wahl Elizabeth , Sikes James , Thakali Keshari
Published: May 2023

Background: While it is known that obesity increases the risk for cardiovascular disease (CVD), there has been no clear investigation into the effect an obesogenic diet exerts onto circulating platelets. As platelets are the critical actors in the formation of occlusive clots that manifest as a myocardial infarction or stroke, it is pertinent to establish any potential link between obesity and platelet activity. Methods: To examine the effect of a Western diet on baseline platelet activity, male C57BL6/J mice were fed either a control (10% fat, 7% sucrose, 0.3% salt Research Diets Inc. D12450J) or Western (40% fat, 30% sucrose, 8% salt Research Diets Inc. D06111701) diet ad libitum for 20 weeks beginning at the time of weaning. At 12, 16 and 20 weeks after beginning diet administration whole blood was collected via the retro-orbital sinus. Blood was used to generate platelet rich plasma (PRP) which was stimulated with collagen (20mg/ml) prior to staining for flow cytometry analysis. Flow cytometry staining utilized antibodies to recognize the platelet receptors GPIbα, P-Selectin and the activated form of integrin αIIbβ3 (JON/A). Additionally, body composition was likewise determined at these time points using Echo-MRI while bodyweight was measured weekly. Results: Western diet fed mice gained slightly more weight than control mice and had a higher percentage of body fat (measured by EchoMRI). Surprisingly, the two groups differed in GPIbα and activated αIIbβ3 expression on circulating platelets at all three observed time points. Specifically, platelets from control-fed mice displayed significantly higher GPIbα expression throughout the study while Western diet fed animals had higher levels of activated αIIbβ3. There was no difference in platelet expression of P-Selectin between the groups at any time point. Conclusions: Platelet activation is not a binary process where platelets display a definitive “active” or “inactive” phenotype. Though terminal platelet activation elicits de-granulation and an increase in P-Selectin expression, the spectrum of platelet stimulation preceding this is marked by variable incidences of integrin activation and GPIbα shedding. Here we demonstrate proof of principle that dietary factors, such as the consumption of a Western diet, can facilitate early changes to the stimulation pattern of circulating platelets which is then maintained long-term. While the consequence of this altered platelet stimulation profile is unknown with regards to the pathways of hemostasis and thrombosis, further investigations of downstream signaling and amplification pathways are needed.

Funding: Arkansas Children's Research Institute/Arkansas Bioscience Institute Postgraduate Fellowship: AWD-037176

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.
The role of estradiol on sensory nerve-mediated dilation in postmenopausal women
Authors: Del Vecchio Angelica , Welti Laura , McGinty Shane , Schwab Allyson , Haigh Katherine , Wong Brett , Wenner Megan
Published: May 2023

BACKGROUND: Local heating of the skin elicits a biphasic vasodilatory response. The initial peak of this response is largely mediated by sensory nerve mechanisms. Receptors for estradiol (E2), the primary form of estrogen, have been found on peripheral sensory neurons indicating E2 impacts the nociceptive response. In animal models, E2 may decrease pain tolerance or act as an analgesic but it is currently unclear how E2 affects sensory nerve-mediated responses in women, particularly in E2-deficient postmenopausal women. PURPOSE: We tested the hypothesis that E2 augments sensory nerve-mediated vasodilation during local heating in E2-deficient postmenopausal women. METHODS: We measured cutaneous vasodilation to local heating (42°C) via laser Doppler flowmetry during microdialysis perfusions of lactated Ringer’s (control) and in a subset (n=4), L-NAME (non-selective nitric oxide synthase inhibition; 15mM) in 10 healthy postmenopausal women (55±2 yrs) at baseline (BL) and after 7 days E2 administration using a transdermal patch (E2; 0.1 mg/day, Vivelle-Dot). Cutaneous vascular conductance (CVC) was calculated as SkBF/MAP normalized to maximal vasodilation achieved by perfusion of sodium nitroprusside (28mM) and heating to 43°C. RESULTS: All women were less than 10 years post menopause (average 5±3 years), normotensive (SBP: 123±12 mmHg; DBP 77±5 mmHg) and not obese (BMI: 24±3 kg/m2). Sensory nerve-mediated dilation was unaffected by E2 administration (E2: 56±8 vs BL: 55±13 %CVCmax; p=0.72). Inhibition of eNOS with L-NAME did not blunt sensory nerve-mediated dilation and was not impacted by E2 (E2: 71±18 vs BL: 56±33 %CVCmax; p=0.55). In a subset (n=5) serum E2 concentration increased after E2 administration (E2: 80.42±11.90 vs BL: 25.74±4.42; p=0.0005) CONCLUSIONS: These preliminary findings suggest E2 administration does not impact sensory nerve-mediated dilation in postmenopausal women. Furthermore, sensory nerve-mediated dilation does not appear to be mediated by nitric oxide. Additional research is needed to further understand the impact of sex hormones and aging on sensory nerve-mediated dilation in women.

Research supported by AHA award 16SDG30700015 and NIH Grant P20 GM113125

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.
Polycystin 1 ciliary localization is controlled by mechanosensitive signaling that involves secretion of ATP
Authors: Gresko Nikolay , Caplan Michael
Published: May 2023

Autosomal dominant polycystic kidney disease (ADPKD) is caused by mutations in the genes, that encode Polycystin1(PC1) and Polycystin 2 (PC2), respectively. PC1 is a 460kD multi-spanning membrane protein that undergoes multiple proteolytic cleavages. At least two of those cleavages release fragments of the PC1 C-terminus. A population of the PC1 protein localizes to the primary cilium where, together with PC2, it is thought to participate in cellular mechano-sensation. PC1 and PC2 can form a cation-permeable heterotetrameric channel that may regulate Ca+2 influx into the cilia. Recent studies demonstrate that PC1 can function as an atypical GPCR and that it can interact with Wnt ligands.We report that activation of the PC1 receptor function regulates its ciliary localization in cultured LLC-PK1 cells and show that this effect can be modified by ligand binding or by mechanical stimuli. The ciliary quantity of the full length PC1 is dramatically reduced by exposure to the PC1-stimulatory ligand Wnt9b. Furthermore, we show that a protein construct that corresponds to a constitutively active form of the PC1 receptor is absent from the primary cilia whereas a protein construct that corresponds to a constitutively inactive form of PC1 is prominently localized to the primary cilia. Inhibition of β-arrestin with barbadin alters the distribution of the constitutively active PC1 construct, resulting in its accumulation in the cilium. Taken together, these data suggest that the ciliary localization of PC1 is governed by its receptor activity through a mechanism that resembles that of GPCR receptor desensitization. We find that mechanical stimuli also lead to removal of PC1 from the cilium. This effect is due to mechanical stimulus-induced release of ATP into the medium. Enzymatic hydrolysis of extracellular ATP prevents the effects of mechanical stimuli on PC1 ciliary localization, whereas addition of exogenous ATP to the medium is sufficient to induce departure of PC1 from the cilium in the absence of mechanical stimuli. We show that both Wnt9b and mechanical stimuli exert their effects on PC1 ciliary localization through the β-arrestin dependent cascade. These findings illuminate an exciting and largely untapped aspect of PC1 biology.

NIH RO1 DK072612 and DOD PR191158

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 varying dietary potassium on the development of salt-sensitive hypertension and expression of basolateral Kir channels
Authors: Zietara Adrian , Levchenko Vladislav , Palygin Oleg , Staruschenko Alexander
Published: May 2023

The inverse effects that dietary sodium and potassium have on blood pressure have been known for some time. High sodium consumption is detrimental, while potassium supplementation is known to be beneficial, and the ratio of sodium/potassium consumption is also very important to consider when determining how these electrolytes affect salt-induced hypertension; however, the mechanisms behind the beneficial effects of potassium are still not yet entirely established. Inwardly rectifying potassium (Kir) channels have been shown to play a major role in potassium transport and homeostasis in the kidney and might contribute to these effects. Here we aimed to examine how different variations in the sodium/potassium ratio affect the development of salt-sensitive hypertension and how channels and transporters in the kidney are altered to accommodate these changes. We hypothesize that these diets will affect the development of salt-sensitive hypertension, and that Kir channels will play a major role in the renal adaptations to varying intakes of potassium. At 9 weeks of age, male Dahl SS rats were given a high salt (4% NaCl) diet for 5 weeks either supplemented with high potassium (HK, 1.41% K+), normal potassium (NK, 0.36% K+), or a potassium depleted diet (DK). Telemetry blood pressure recordings revealed that potassium supplementation attenuated the development of salt-sensitive hypertension in rats fed HK diet compared to NK; surprisingly, the DK group did not develop hypertension. Diets had a similar effect on heart rates, we observed the largest heart rate in the NK group, which was reduced with HK, and even further reduced in DK. Comparing terminal body weights, there was no difference between the HK and NK groups, but rats fed DK diet were significantly smaller. The 2 kidney/total body weight ratios were not different in the HK and NK groups, but the potassium deficient rat kidneys were significantly larger, likely due to their smaller body weights. There was no difference in heart/body weight ratios in the HK, NK, or DK groups; however, there is a trend in increased heart weight the lower the dietary potassium. Female animals were also utilized for experiments and followed similar trends as seen in the male rats. Western blot analyses further revealed the expression of Kir channels in Dahl SS rats fed a high salt diet supplemented with varying amounts of potassium. Altogether we provided a comprehensive analysis of various potassium diets on the development of salt-sensitive hypertension and Kir channels.

National Institute of Health R35 HL135749 and the Department of Veteran Affairs I01 BX004024

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.
Diversifying Anatomical Models
Authors: Carroll Jazmine , Bouslog Yosajandy , Brown Isabella , Jones April , Zunick Peter , Leal Anna
Published: May 2023

To increase diversity in health and science, technology, engineering, and math (STEM) fields, it is imperative to create inclusive laboratory tools and environments for students. Unfortunately, most human anatomical models depict white males who are young and lean. This limited representation may discourage students who are considering careers in STEM fields and medicine. Therefore, we painted anatomical models to represent more diverse skin tones. First, the models (3B Deluxe Human Torso) were taped with painters' tape to cover areas that did not need to be painted. Then, the models were cleaned using alcohol prep pads to remove any excess dirt or dust. Commercial grade interior paint (Valspar Satin Interior Paint in colors Cordovan and Cowboy Hat) was applied to the anatomical models with paint brushes (Master’s Touch soft nylon). To create more realistic skin tones, we mixed red and blue acrylic paints (Master’s Touch in Permanent Red and Phthalocyanine Blue) into each paint shade to achieve unique colors. Three layers of paint were applied to each model and each layer dried within one hour. Details such as lip and eye color and hair texture were also added to the models. To maintain the longevity of the paint, clear varnish (Liquitex Finishing Varnish in Satin) was applied. The total process (preparation, paint, and dry time) for one model took a total of five hours. One of the primary goals of our work is that our painting process can be used as a blueprint for other educators and medical professionals to increase inclusivity in their learning spaces and labs and further diversify their anatomical education tools. Creating an inclusive education experience may encourage more students of color and underrepresented minorities to pursue health and STEM graduate degrees. This will increase healthcare quality for patient populations and move the field towards greater health equity.

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.
Evaluation of interactions between nesfatin-1 and B lymphocytes
Authors: Steffen Tara , Kolar Grant , Samson Willis , Yosten Gina
Published: May 2023

The function of nesfatin-1, corresponding to the nucleobindin2 (NUCB2) precursor, was first identified in the hypothalamic nuclei, and was reported to be potently anorexigenic (Oh-I et al. 2006). More recently it has been shown that expression of Nesfatin-1 is not restricted locally to the hypothalamus but is widely expressed in many peripheral tissues, including adipose tissue, and associated with a range of physiological effects. For example, when Nesfatin-1 is genetically knocked out ( Nucb2-/-) in mice fed a high fat diet there is a resultant increase in the gene expression of pro-inflammatory mediators and cytokines, including Tlr4, in the subcutaneous white adipose tissue compared to WT animals also fed a high fat diet. These data support that Nesfatin-1 has anti-inflammatory properties, but the mechanistic actions of this peptide in this setting have yet to be fully described (Gharane et al. 2022). To begin to evaluate the interactions of Nesfantin-1 and immune cells more in depth we began with B lymphocytes where Nubc2, the Nesfatin-1 precursor, was originally identified (Miura et al. 1993). Using an immortalized B lymphocyte cell line, Raji, and primary cells from human donors we determined the ability of Nesfatin-1 to bind to the cell surface and affect B lymphocyte proliferation. Furthermore, we determined if treatment with Nesfatin-1 is sufficient to protect against toll like receptor-4 (TLR4) and B cell receptor (BCR) induced cytokine and antibody release from B lymphocytes. This work is the beginning characterization of a novel interaction between Nesfatin-1 and B cells. Given the anti-inflammatory activity of Nesfatin-1 and its potential direct effects on immune cells, there is a broader impact for this work in protection during chronic inflammation caused by obesity and metabolic disorders.

Saint Louis University

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.
The Anoctamin 4 Homolog Limits Bacterial Infection and Calcium Oxalate Crystallization in Drosophila Renal Tubules
Authors: Foresto-Neto Orestes , Turin Daniel R. , Holmes Heather L. , Reynolds Carmen J. , Arneson Mariah L. , Cabrero Pablo , Jayachandran Muthuvel , Dow Julian A.T. , Lieske John C. , Furrow Eva , Romero Michael F.
Published: May 2023

Anoctamins (ANO) are activated by intracellular Ca2+ and function as phospholipid scramblases and/or Cl- channels. ANO4 is mutated in miniature schnauzers with calcium oxalate stones (CaOx), and ANO4 protein in urinary extracellular vesicles is decreased in human CaOx stone formers. In Drosophila Malpighian tubules (MT), subdued (ANO4-homolog) functions as Ca2+-activated Cl- channel, scramblase, and plays a role in host defense against gram-negative bacteria. Increasing evidence shows the participation of bacteria in urinary stone formation in humans. We used a Drosophila avatar to investigate whether subdued changes CaOx crystallization and if crystallization increases with bacterial infection.Uro:Gal4 flies were crossed with UAS:subdued-RNAi flies to knockdown (KD) subdued in MT principal cells (PC) or with w1118 flies to generate normal controls (WT). F1 generation underwent CaOx crystallization in association or not with uropathogenic E. coli (UPEC) infection. In vivo, flies were fed on diet supplemented with 20mM sodium Ox (NaOx) + UPEC:eGFP for 4 days. For ex vivo assays, dissected MTs were submerged in solution containing 10mM NaOx+ UPEC:eGFP for 90 minutes. subdued-KD in PC reduced subdued mRNA by 56% in MT. Neither crystal number nor size were changed by subdued-KD after prolonged NaOx feeding. However, when UPEC is introduced with the NaOx diet, subdued-KD flies exhibited a large bacterial presence in MT lumen and produced enlarged CaOx crystals compared to WT flies. Similar augmented presence of UPEC in subdued-KD MTs was observed during ex vivo assays. Short-term exposure to NaOx+UPEC resulted in increased number of crystals in subdued-KD MTs compared to WT MTs, but no difference was observed in crystal size.Fly cell atlas ( flycellatlas.org ) revealed that subdued is also found in MT stellate cells (SC; water and Cl- secretion). C724:Gal4>UAS:subdued-RNAi flies were used to assess the effect of subdued-KD in SC. This s ubdued-KD slightly increased bacterial infection but did change CaOx crystallization in MTs after 4 days of NaOx+UPEC feeding.The presence of subdued in PC limits CaOx crystals formation and aggregation through reducing bacterial invasion in the MT lumen. These Drosophila results suggest a role for ANO4 in bacterial-related human and dog kidney stone formation. Future experiments will determine whether other functional aspects of subdued affect CaOx crystallization.

U54-DK100227, R01-DK092408, FAPESP (2022/01226-1), Mayo Foundation.

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.
Up-regulation of the kidney renin angiotensin system contributes to long-term renal dysfunction in severe food restricted-refed female rats
Authors: Patel Riddhi , Milicic Stanic Branka , Ji Hong , Ecelbarger Carolyn , de Souza Aline
Published: May 2023

Background: Severe food restriction (sFR) due to various psychological, environmental, and economical reasons can have adverse consequences to cardiovascular functioning and health. Less understood are the long-term risks for developing cardiovascular disease after the sFR period has ended. The renin-angiotensin system (RAS) is responsible for regulating blood pressure and we have found that the RAS is chronically upregulated months after the sFR is over and body weight (BW) recovered due to refeeding (sFR-Refed). AIM: Determine the role of the kidney in the chronic up-regulation of the RAS in sFR-Refed rats. Methods: We investigated the long-term consequences of sFR after refeeding on kidney structure and function in sFR-Refed rats. Female Fischer rats (3-months-old) were maintained on normal chow (Ctrl) ad libitum or a 60% caloric restricted diet for 2 weeks. Thereafter, all rats received regular chow ad libitum for 3 months. Kidney function was analyzed by precision ultrasound. ACE expression (qPCR) and activity (fluorescent assay) were measured and renal pathology was assessed by H&E staining. Results: After 2 weeks of sFR, rats lost 15% of their initial BW [DFinal/Initial): Ctrl, 1.50±0.80 vs sFR, -15.4±1.1; p<0.001; n=8]. After 3 months of refeeding, there was no detectable difference in BW, blood pressure and heart rate between Ctrl and sFR-Refed groups. However, the renal artery blood flow was reduced by 13% [(mm/s): Ctrl, 255 ± 12 vs sFR-Refed, 199 ± 7.8; p<0.02; n=4-8 Glomeruli size was reduced [(mm): Ctrl, 399 ± 6.2 vs sFR-Refed, 383 ± 3.8; p<0.05; n=9] and renal AT1R mRNA expression was increased by 1.3-fold [(fold of Ctrl): Ctrl, 1.00 ± 0.060 vs sFR-Refed, 1.29 ± 0.040; p<0.005; n=8]. Conclusion: In summary, AT1Rs in the renal cortex are up-regulated under conditions in which kidney structure and function are impaired months after the sFR period has ended and BW is restored to normal levels. These findings suggest increased renal AT1R activity contributes to the long-term renal dysfunction observed in sFR-Refed rats. Further research is needed to understand how women who are subjected either voluntarily (e.g., crash diets) or involuntarily (e.g., very low food security) to periods of inadequate caloric intake could be at increased risk for developing renal disease later in life.

AHA: 940246 (AS); IH 1R01HL119380 (KS)

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.
Adenylate Cyclase 3 and Cyclic Nucleotide-Gated Channel Alpha 2 Are Downstream Signaling to H2S/Olfr78 to Carotid Body Responses to Hypoxia
Authors: Peng Ying-Jie , Wang Ning , Nanduri Jayasri , Chen Xuanmao , Storm Daniel , Prabhakar Nanduri
Published: May 2023

We previously showed that activation of Olfr78 by H2S as an important component of carotid body(CB) O2 sensing. Present study delineated signaling associated with H2S/Olfr78 interaction. Odorant receptor activation is linked to olfactory G protein GOlf, which increases cAMP through type III adenylyl cyclase (AC3), and subsequent activation of cyclic nucleotide-gated channel alpha 2 (Cnga2). Immunohistochemistry showed that carotid body glomus cells were positive for GαOlf, AC3, and Cnga2. Hypoxia (medium Po2~40 mmHg) or H2S(50 μM) increased cAMP in the carotid body and these responses were absent in tyrosine hydroxylase-specific AC3 mutants. AC activators forskolin and 8-Bromo-cAMP enhanced ex vivo CB sensory response to hypoxia and H2S. The effects of 8-Bromo-cAMP were absent in Cnga2 mutants. Hypoxia and H2S stimulated ex vivo CB sensory activity and elevated intracellular calcium of glomus cells in wild type but not AC3 or Cnga2 mutants. Whole body plethysmography showed impaired ventilatory response to acute hypoxia (12%O2, 5 min) but not to hypercapnia in AC3 or Cnga2 mutants. The data suggest that AC3-cAMP-Cnga2 signaling contributes to H2S/Olfr78-dependent O2 sensing by the CB to regulate breathing.

Supported by NIH-HLBI P01-HL-44454

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.
ApoE4 undermines phrenic motor plasticity elicited by acute intermittent hypoxia with or without hypercapnia during the active phase
Authors: Marciante Alexandria , Nair Jayakrishnan , Welch Joseph , Mitchell Gordon
Published: May 2023

Acute intermittent hypoxia (AIH) elicits respiratory motor plasticity and is emerging as a promising strategy to improve breathing and other (non-respiratory) movements in clinical disorders that end life due to respiratory insufficiency ( e.g., spinal cord injury & ALS). AIH-induced phrenic long-term facilitation (pLTF) is the most commonly studied form of respiratory motor plasticity and presents as a persistent increase in phrenic nerve activity after AIH. Specific factors ( e.g. aging, inflammation, hypoxia severity/duration) undermine AIH-induced pLTF; however, little information is available concerning the role of specific genes that regulate AIH-induced phrenic motor plasticity. Apolipoproteins (ApoE) are highly expressed in the central nervous system and function as lipid carriers. The ApoE gene is tri-allelic ( E2, E3 and E4); ApoE2 and E3 proteins are associated with neuroprotective and neuro-neutral phenotypes, respectively. ApoE4 impairs cortical and synaptic plasticity and is implicated in neurodegeneration, particularly Alzheimer’s Disease. Indeed, humans heterozygous for ApoE4 ( e.g., ApoE3/4) have reduced plasticity in diaphragm motor-evoked potentials versus non- ApoE4 carriers using an optimized protocol combining AIH with hypercapnia (AIHH; 15, 1 min O2=9.5%, CO2=5% episodes). To demonstrate causality, we tested the hypothesis that ApoE4 undermines AIH-induced pLTF vs ApoE3 in knock-in rats. Anesthetized, vagotomized, paralyzed and ventilated adult (3-4 months) male Sprague-Dawley rats with knock-in humanized (h) ApoE3 and (h) ApoE4 were presented with AIH (15,1 min hypoxic episodes; O2=9%; arterial PO2 = 40-50mmHg) or AIHH (inspired CO2=4%; arterial PCO2=50-55 mmHg). During the mid-active phase, AIH-induced pLTF was significantly greater in h ApoE3 (33±11%) vs h ApoE4 rats (-22±7%; p<0.001; both n=5). AIHH enhanced pLTF in h ApoE3 rats (60±11%; n=4) vs AIH, alone (p=0.046), but not h ApoE4 rats (-3±7%; n=3; p=0.970). These experiments demonstrate a causal relationship whereby ApoE4 undermines both AIH- and AIHH-induced pLTF during the active phase in rats. Since AIH has emerged as a promising neurotherapeutic to preserve/restore breathing in clinical disorders such as spinal cord injury and neuromuscular disease, understanding how genetic factors impact phrenic motor plasticity will help identify individuals most/least likely to respond to treatment. Such biomarkers are essential for success/failure in the translation of AIH/AIHH as a therapeutic modality.

NIH (HL148030, HL149800 & T32HL134621), Craig H. Neilsen Foundation (JW) and UF Brain and Spinal Cord Injury Trust Fund (BSCIRTF).

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.
Extracellular histone proteins are novel activators of P2XR7 channel current
Authors: Al-Aqtash Rua'a , Collier Daniel
Published: May 2023

Extracellular histone proteins have been identified as important damage associated molecules that contribute to vascular dysfunction. Histones are elevated in circulation after traumatic injury and activation of the innate immune response. In prior work, we demonstrated that extracellular histone proteins induced endothelial cell (EC) Ca2+ influx, increased EC propidium iodide labeling, and decreased vasodilatory responses. These paradoxical observations could be explained by activation of a non-selective cation channel. The ionotropic purinergic receptor 7 (P2XR7) stands out as a candidate as it has been shown to form a high-conductance, poorly selective, cation channel capable of conducting large cationic dyes. Herein, we test the hypothesis that P2XR7 channels are activated by histone proteins. We expressed mouse P2XR7 (C57BL/6J variant 451L) in heterologous cells ( Xenopus oocytes) and measured inward cation current using two-electrode voltage clamp (TEVC). Cells expressing mouse P2XR7 had robust ATP- and histone-evoked inward cation currents. ATP- and histone-evoked currents reversed approximately at the same potential. Current decay with agonist removal was much slower for histone-evoked than ATP- or BzATP-evoked currents. As with ATP-evoked P2XR7 currents, histone-evoked currents were inhibited by non-selective P2XR7 antagonists (Suramin, PPADS, and TNP-ATP). GW791343, a selective P2XR7 antagonist with a known binding site distinct from the ATP binding site, inhibited ATP-evoked currents but did not inhibit histone-evoked currents. As with ATP-evoked currents, histone-evoked P2XR7 currents were also increased in conditions of low extracellular Ca2+. These data demonstrate that P2XR7 is necessary and sufficient for histone-evoked inward cation currents. These results suggest a new allosteric mechanism of P2XR7 activation by histone proteins that may guide the development of more effective P2XR7 pharmacology and therapeutic strategies for a wide array of pathologies that involve P2XR7 function.

DMC is supported by NIH R00HL133451 and R01HL155180

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.
Emotional responsiveness to daily stress is related to exaggerated cardiovascular stress reactivity in adults with major depressive disorder
Authors: Darling Ashley , Dominguez Cynthia , Mogle Jacqueline , Saunders Erika , Almeida David , Greaney Jody
Published: May 2023

Increased frequency of exposure and affective responsivity to daily stressors are predictive of future cardiovascular disease (CVD)-related health outcomes and mortality. Profound stress system dysfunction is a hallmark characteristic of major depressive disorder (MDD), likely contributing to MDD-CVD comorbidity. Although a greater increase in negative affective responsivity (NA-R) to daily stress is evident in adults with MDD, whether this is linked to heightened cardiovascular stress reactivity remains unclear. We hypothesized that the slope of the positive relation between daily stress (quantified as both exposure frequency and NA-R) and the magnitude of acute stress-induced increases in heart rate (HR) and blood pressure would be steeper in adults with MDD compared to healthy non-depressed adults (HA). For 8 consecutive days, stressful events encountered in everyday life and while in naturalistic environments (e.g., argument with a partner) were assessed via an ambulatory daily diary in 40 HA (22±4 yrs; 24 female) and 40 adults with MDD (23±6 yrs; 32 female). On the last day of the daily dairy, HR (electrocardiogram) and mean arterial pressure (MAP; finger photoplethysmography) were measured during the cold pressor test (CPT). Daily stress exposure frequency was calculated as the percentage of days with at least one stressor reported across the 8-day protocol, and NA-R was calculated as the intra-individual slope of the change in negative affect on stressor days (at least 1 stressor) compared to negative affect on stressor-free days (no stressors). There were no group differences in the frequency of daily stressor exposure [36±26 (range: 0-100) HA v 41±23% (range: 0-100) MDD; p=0.32]; however, as expected, NA-R was greater in adults with MDD [0.23±0.10 (range: 0.09-0.52) HA vs 0.34±0.16 a.u. (range:0.09-0.71) MDD; p<0.01]. Daily stressor exposure frequency was not related to CPT-induced increases in HR or MAP in either group (all p>0.05). However, NA-R was positively related to both the CPT-induced increase in HR (β=35.18, SE=9.04, p<0.01) and MAP (β=20.20, SE=9.16, p=0.03) in adults with MDD but not in HA (HR: β=2.89, SE=21.23, p=0.89; MAP: β=1.70, SE=17.78, p=0.92). These data suggest that increased emotional vulnerability to common stressors that occur in naturalistic environments and as a part of day-to-day living is linked to potentiated cardiovascular stress reactivity in young adults with MDD, likely contributing to increased CVD risk.

NIH R21MH123928 and R00 HL133414

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 DOCK2 and KCa3.1 in fibroblast-to-myofibroblast transformation
Authors: Stiens Sara , Bowles Doug
Published: May 2023

Excessive fibroblast-to-myofibroblast transformation is accompanied by injurious deposition of extracellular matrix components and tissue fibrosis. Fibrosis underlies many disease processes, including systemic sclerosis, idiopathic pulmonary fibrosis, liver cirrhosis, kidney fibrosis, and heart failure. Inhibiting fibroblast transformation is a major therapeutic strategy for the attenuation of these conditions. The aim of the present study is to determine the role of two proteins, dedicator of cytokinesis 2 (DOCK2) and the intermediate-conductance calcium-activated potassium channel (KCa3.1), in fibroblast-to-myofibroblast transformation. We hypothesized that DOCK2 and KCa3.1 stimulate fibroblast transformation. Cultured NIH/3T3 fibroblasts were treated with transforming growth factor β (TGFβ) in the presence and absence of inhibitors of DOCK2 (CPYPP, 10 μM) and KCa3.1 (TRAM-34, 100 nM). After 24 hours, mRNA was collected, transcribed into cDNA, and quantified with qRT-PCR. We found that CPYPP prevented TGFβ-induced transcriptional upregulation of the genes Acta2 (4.28 ± 0.18 vs 0.30 ± 0.01, n=4, p<0.001) and Col1a (2.51 ± 0.28 vs 0.14 ± 0.01, n=4, p<0.001), both indicators of fibroblast transformation. Similarly, TRAM-34 attenuated TGFβ-induced transcriptional upregulation of Acta2 (17.27 ± 0.81 vs 12.23 ± 1.26, n=4, p<0.01) with a similar trend for Col1a (1.88 ± 0.23 vs 1.33 ± 0.07, n=4, n.s.). We also determined that the role of DOCK2 in fibroblast transformation was at the post-transcriptional level since TGFβ did not increase mRNA expression of Dock2 (n=16). We conclude that DOCK2 and KCa3.1 are both involved in TGFβ-induced fibroblast-to-myofibroblast transformation. Future experiments will determine whether there is an interaction between DOCK2 and KCa3.1 in fibroblast transformation.

NIH R01 HL151444 to DKB

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.
Effect of obesity on the vascular response to sympathetic activation during hypoxia in female participants
Authors: Jacob Dain , Shariffi Brian , Gonsalves Anna , Harper Jennifer , Limberg Jacqueline
Published: May 2023

Background: Activation of the sympathetic nervous system causes vasoconstriction and an acute reduction in peripheral blood flow. However, during hypoxia, sympathetically-mediated vasoconstriction is attenuated in young females without obesity. Given sustained increases in sympathetic activity associated with obesity may create a greater propensity to vasoconstrict in response to sympathetic activation, we sought to examine the effect of obesity on the vascular response to sympathetic activation during hypoxia. We hypothesized sympathetically-mediated vasoconstriction during hypoxia would be greater in premenopausal female adults with obesity when compared to females without obesity. Methods: Blood pressure (BP, finger photoplethysmography) and forearm blood flow (FBF, venous occlusion plethysmography) were assessed in premenopausal female adults with obesity (n=5, 25±3 yrs, 37±1 kg/m2, 48±1% body fat) and without obesity [n=19, 23±1 yrs, 23±1 kg/m2, (33±2% body fat, n=8)]. Data were combined from two cohorts (IRB #2022525, 2011312) to test present hypotheses. Participants completed two trials consisting of a 2-min cold pressor test (CPT) during baseline normoxia (98±1% SpO2) and following 3-5 min of steady-state hypoxia (0.10±0.01 FiO2, 82±1% SpO2). FBF was normalized for BP (forearm vascular conductance, FVC) and a change in FVC during the last 1-min of CPT was calculated (ΔFVC). The main effect of group (obese, non-obese), condition (normoxia, hypoxia) and the interaction of group and condition were compared using a two-way repeated measures ANOVA. Results: In female participants without obesity, ΔFVC during normoxia was attenuated during hypoxia (-0.57±0.19 vs +0.36±0.34 mL/dL/100mmHg/min; p=0.009). Conversely, in female participants with obesity, ΔFVC during normoxia did not differ from the response during hypoxia (-0.31±0.46 vs -0.87±0.34 mL/dL/100mmHg/min; p=0.382). Group differences in ΔFVC were not observed during normoxia (p=0.657), but were present during hypoxia (p=0.039). Conclusion: Sympathetically-mediated vasoconstriction is attenuated during steady-state hypoxia in premenopausal females without obesity, whereas this response is not observed in female adults with obesity. These preliminary data advance our understanding of the impact of obesity on hypoxic vascular control in premenopausal female participants and have implications for conditions in which hypoxia and sympathetic activation are observed ( e.g., sleep apnea, heart failure, COVID-19).

NIH HL130339 (JKL), NIH HL153523 (JKL), AHA 909014 (DWJ)

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.
Human Genetics and Dyslipidemia: From Non-synonymous Variants to Non-coding Variants
Authors: Wang Yan , Wang Yan , Liu Xiao , Liu Yinan
Published: May 2023

Dyslipidemia has strong heritability, with over 50% of dyslipidemia is caused by genetics in general population. Previously studies identify many non-synonymous variants in genes of LDLR, PCSK9, ANGPTL3, ABCG5/8, ARH et.al, which lay the fundation for durg development. However, these known non-synonymous variants can only explain about 10-20% of genetic risks. Genome-wide association studies (GWAS) have identified hundreds of genetic variants associated with dyslipidemia in large population. However, about 95% of these variants are located in genome noncoding regions and cluster in different loci. The disease-causing variant for each locus and underline mechanism remain largely unknown. We systematically analyzed these noncoding variants and found that rs1997243 is the disease-causing variant in locus 7p22, which is strongly associated with hypercholesterolemia. The rs1997243 risk allele is associated with increased expression of GPR146 in human and specifically up regulates GPR146 expression in cultured hepatocytes. GPR146 is an orphan G-protein coupled receptor that is located on plasma membrane and responses to stimulation of heat-inactivated serum. Disrupting gpr146 specifically in the liver decreases the blood cholesterol level and prevents high-fat or high-fat high-cholesterol diets induced hypercholesterolemia in mice. Mechanistic study suggests that GPR146 regulates blood cholesterol level mainly through regulating the catabolism of cholesterol rich lipoprotein particles. Thus we uncovered a novel G-protein coupled receptor that regulates blood cholesterol levels in both humans and mice. Our results also suggest that antagonizing GPR146 function will be an effective strategy to treat hypercholesterolemia.

National Key Research and Development Program of China (2018YFA0800700), the National Natural Science Foundation of China (92057207, 91754101, 32021003, 31771304)

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.