bluuebunny/crossref_metadata_2025 huggingface dataset:
Dual rotations of rods on thermosolutal convection in a porous cavity suspended by nanoencapsulated phase change materials
Authors: Alhejaili Weaam , Aly Abdelraheem M.
Published: May 2023

The fractional of a time derivative for the incompressible smoothed particle hydrodynamics (ISPH) method is adopted to handle thermal radiation on thermosolutal convection in a porous cavity barred by nanoencapsulated phase change materials (NEPCMs). A novel work on the rotational velocities of two rods during thermosolutal convection of NEPCMs within a novel cavity of two connected circular cylinders is introduced. The management of heat-mass transfer and velocity magnitude inside distinct designed materials below various boundary conditions carries improvements for energy efficiency. The physical factors are thermal radiation [Formula: see text], Fusion temperature [Formula: see text], Rayleigh number [Formula: see text], hot source length [Formula: see text], Darcy number [Formula: see text], and fractional order parameter [Formula: see text]. This study reported the role of thermal/solutal conditions in varying the dual convection flow and heat capacity contour. The lower Da provides an elevated porous resistance which decelerates the nanofluid velocity. The fusion temperature alters a heat capacity contour.
Steady state concentration in an amperometric biosensor using mathematical modeling
Authors: Govindan Vediyappan , Xin Xiao , Vignesh S. , Sudha P. N. , Sankeshwari Sagar Ningonda , Vairavel T. Muthukani , Prakash R. , Chithra S. M. , Bala A. Jyothi
Published: May 2023

This paper presents an analytical solution to the model. By solving the system of nonlinear reaction-diffusion equations using Akbari–Ganji’s method (AGM), we can derive the semi-analytical expressions for substrate and oxidized and reduced mediator concentrations. These models provide information about enzyme electrode mechanisms and their kinetics. These modeling results can be helpful for sensor design, optimization, and determining how the electrode will react. Further, we studied the effects of many physical and biological parameters on model prediction. The mathematical equations, which are nonlinear partial differential equations, are solved using AGM. Also, we derived the semi-analytical results for concentrations for saturated and unsaturated kinetics. It is verified that the proposed solution is validated by comparing it with numerical solutions.
Soliton molecules in coupled dipolar Bose–Einstein condensates with spin-orbit coupling
Authors: Mboumba Maïk Delon , Makoundit Gleann Juvet Ngounga , Sadem Christian Kenfack , Moubissi Alain Brice , Kofané Timoléon Crépin
Published: May 2023

Recent research works on ultra cold quantum gases demonstrated that dipolar Bose–Einstein condensates (BECs) exhibit rich spatiotemporal dynamic where both local and nonlocal interactions are considered. We explore theoretically the possibility of controlling the formation and dynamics of soliton molecules in binary dipolar condensates with spin-orbit coupling (SOC). We exploit the variational technique to derive the new equations of motion for the widths and amplitudes, the effective potential and the oscillation frequency of the molecules. Our study confirms the existence of stable localized bound states in an optical potential. We find that the integrity of the molecules is influenced by the physical parameters, notably the local and nonlocal interactions with the SOC. These parameters are carefully chosen by the Vakhitov–Kolokolov (VK) criterion to ensure the stability of the molecules. We present the results of numerical experiments and confirm the analytical predictions. Moreover, we show the soliton–soliton interaction in each molecule when the local interactions are strong.
Impact of total parenteral nutrition and antibiotics on hepatic and intestinal homeostasis in pediatric murine model
Authors: Pierre Joseph , Mims Tahliyah , Kumari Roshan , Joseph Sydney , Leathem Cameron , Antunes Karen , Al Abdallah Qusai , Henry Lydia , Ferstl Danielle , Jamieson Sophia , Sabbar Austin , Willis Kent , Talati Ajay , Elabiad Mohamad , Hibl Brianne
Published: May 2023

Parenteral nutrition (PN) prevents starvation and supports metabolic requirements intravenously when patients are unable to feed enterally. Adult rodents and piglets have been used in PN research for decades, while almost no research has used adolescent mice. Clinically, human neonates are frequently provided PN in intensive care settings along with exposure to antibiotics (ABX) to minimize infection during care. Since PN bypasses the intestine, intravenous alimentation impacts metabolism and may alter organ growth and programming during critical early life developmental windows. Utilizing our newly established adolescent murine PN model, we first administered ABX or controlled drinking water to time pregnant dams to disrupt maternal microbiome. Resulting pups (post-natal day 9, n=6-8/group) were then randomized to PN or sham surgery controls for 72 hours with or without prior ABX exposure. ABX or PN decreased liver and brain organ weights, intestinal length, and mucosal architecture compared with controls. PN significantly elevated hepatic proinflammatory cytokine expression, neutrophils, macrophages, and bacterial colony forming units, which was blocked by ABX. However, PN+ABX uniquely elevated metabolic regulatory genes, FXR, CYP27A1, SPEBP1, and FASN, resulting in accumulation of hepatocyte lipid vesicles and altered circulating bile acid pools. Within the gut, PN elevated the relative abundance of Akkermansia, Coprococcus and decreased Lactobacillus compared with enteral controls, while ABX enriched Enterobacteriaceae and Adlercrutzia. We conclude that even brief PN feeding elevates hepatic inflammatory stress in an early life model. While concurrent ABX exposure protects against PN associated inflammatory responses, the dual therapy modulates bile acid and lipid metabolism, which may contribute to the progressive hepatic dysfunction observed in human neonates unable to wean from PN. This study serves as the first demonstration of PN and ABX exposures upon hepatic metabolism and inflammation in an early life murine model.

Institutional Start Up Funding

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 Spike protein of SARS-CoV-2 exacerbates cardiac mitochondrial dysfunctions in obese mice: mechanistic evidence for cardiomyopathy in post-acute sequelae of COVID-19
Authors: Nguyen Vi , Cao Xiaoling , Tsai Joseph , Tian Yan , Zhang Yuping , Gao Chao , Carver Wayne , Kiaris Hippokratis , Cui Taixing , Tan Wenbin
Published: May 2023

Background: As the pandemic persists, post-acute sequelae of CoV-2 (PACS) including cardiovascular manifestations have emerged as a new health threat. Obesity is an established risk factor for acute COVID-19 severity. Evolving evidence has suggested its contributive roles in the pathogenesis of PACS. However, whether and how obesity can exacerbate PACS-related cardiomyopathy is unknown. Methods: A Spike protein-pseudotyped (Spp) virus with the proper surface tropism of SARS-CoV- 2 was developed for viral entry assay in vitro and administration into high fat diet (HFD)-fed mice. The systemic viral loads and cardiac transcriptomes were analyzed at 2 and 24 hrs, 3, 6, and 24 weeks post infection (wpi) using RNA-seq or real time RT-PCR. Echocardiography was used to monitor cardiac functions. Results: Low-density lipoprotein cholesterol enhanced viral uptake in endothelial cells, macrophages, and cardiomyocyte-like H9C2 cells. Selective cardiac and adipose viral depositions were observed in HFD mice but not in normal-chow-fed mice. The cardiac transcriptional signatures in HFD mice at 3, 6, and 24 wpi showed systemic suppression of mitochondria respiratory gene families including ATP synthases and nicotinamide adenine dinucleotide:ubiquinone oxidoreductase gene members, upregulation of stress pathway-related crucial factors such as nuclear factor-erythroid 2-related factor 1, and increases in expression of glucose metabolism-associated genes. Cardiac ejection fraction and fractional shortening were significantly decreased, while left ventricular end-systolic diameter and volume were significantly increased, in HFD mice at 24 wpi as compared with the age-matched HFD control mice. Conclusion: Our data demonstrated that chronic cardiac inflammations were persisted and exaggerated in HFD mice after viral infection, leading to mitochondrial metabolic perturbations and myocardial contractile impairment.

This work was supported by grants from the National Institutes of Health (AR073172 and NIH COBRE (P20GM109091) pilot study to W.T., NSF EPSCoR (OIA1736150) to H.K., HL160541 to T.C.).

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.
Three levels of enhanced inspired CO2 or fasted-state on stress response activation in behaviorally inhibited humans and rats
Authors: Wolf Olivia , Harshberger Mary , Apostoli Giana , Ehlert Luke , Wiseman Connor , Martino Paul , Miller Daniel , Miller Justin , Terrill Sarah , Hodges Matthew , Allen Michael
Published: May 2023

Behavioral inhibition (BI) is believed to be a genetically determined trait that affects roughly 33% of the human population. These individuals tend to respond to stressful situations differently than their non-behaviorally inhibited (NBI) counterparts. In the rodent population, a similar behavioral/stress model exists. The Sprague-Dawley (SD) strain often acts as a “control” among rat strains and can be considered to be the rat equivalent to NBI individuals, and the Wistar-Kyoto (WKY) strain is the rodent equivalent to BI individuals. The differences in the activation of the sympathetic nervous system between chronically stressed and non-stressed populations remain unknown. Our current study tested the hypothesis BI individuals and WKY rats will have increased stress responses. In humans, we tested physiological responses to increasing levels of carbon dioxide (CO2) through analyses of breathing, heart rate, and blood pressure. The Adult Measure of Behavioral Inhibition (AMBI) survey was used to determine the presence of BI. A 15-minute control period baseline was completed followed by an acquisition period of five minutes of each 3%, 5%, and 7% CO2, respectively. Preliminary results were analyzed through a CO2 sensitivity slope (inspired minute ventilation ((L/min) / end-tidal CO2) and show that BI individuals had increased, exaggerated responses to the respiratory stressors across the three levels of enhanced CO2. In the rodent model, signaled lever-press avoidance was used to examine the activation of stress responses. Rats were trained to avoid mild foot shock using a tone warning signal. As demonstrated previously, WKY rats acquired a higher level of avoidance responses. Rats were then food-deprived overnight and subsequently retested on signal lever-press avoidance. Food deprivation did not affect the high rate of avoidance seen in WKY rats; however, food deprivation increased the SD rate of avoidance to nearly the level of WKY rats. Our data suggest that WKY rats do not respond to food deprivation when paired with lever-press avoidance; however, SD rats do. Simply, the addition of a stressor causes SD rats to behave more similarly to their WKY counterparts.

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 Sphingosine Kinase 1 in the Pathogenesis of Idiopathic Pulmonary Fibrosis: Identification of Novel Transcription Factors as Potential Therapeutic Targets by in silico Analysis
Authors: Krishnan Yashaswin , Sudhadevi Tara , Ramachandran Ramaswamy , Natarajan Viswanathan
Published: May 2023

Introduction: Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease with no definitive treatment. However, a bioactive lipid mediator, sphingosine-1-phosphate (S1P) has been identified to have a role in the pathogenesis of IPF. S1P is synthesized from sphingosine by iso-enzymes sphingosine kinase (SPHK) 1 & 2. In animal models of IPF, genetic knockout of Sphk1 or inhibition of SPHK1 protected the lungs from fibrosis induced by inciting agents. SPHK1 expression is upregulated in IPF; however, the mechanism(s) of its upregulation remain unclear. Hypothesis In silico analysis can predict transcription factors (TFs) that could bind to the promoter region of mouse Sphk1, upregulating its transcription. This could help predict therapeutic targets for IPF in mouse models. Methods: MatInspector® software tool of Genomatix Inc. (Germany) was used for in silico analysis of TF binding sites in Sphk1. This tool uses the available pool of data for TF binding sites to predict probable binding sites in the DNA nucleotide sequence. Results A search for Sphk1 transcript in mouse using gene ID 20698 with accession numbers GXP_6660985, 9541363 and 10224577 yielded 2,119 matches in chromosome 11. GXP_6660985, with the highest probability of TF binding, was the main transcript. The top 100 TF binding sites were analyzed. Among these, 24 binding sites relevant to lung tissue had a very high probability of binding with matrix similarity of 0.98 to 1.0. The TFs included GREF, STAT, SMAD and FKHD. Among these, seven TFs and their binding sites were not cited in the literature according to MatInspector®. Conclusions: A total of 12 TFs were identified in lung tissue as potential members of transcription initiation complex for Sphk1 gene in mouse.Future direction: In silico analysis of TF binding for human SPHK1 is in progress. Modulation of these TFs could serve as a potential therapeutic tool for IPF.

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 BBSome Regulates Mitochondria Dynamics and Function
Authors: Guo Deng , Merrill Ronald , Qian Lan , Zhang Qi , Lin Zhi , Thedens Daniel , Usachev Yuriy , Grumbach Isabella , Sheffield Val , Strack Stefan , Rahmouni Kamal
Published: May 2023

The essential role of mitochondria in physiology and many pathologies has garnered enormous interest in understanding the mechanisms controlling the function of this organelle. The BBSome, a protein complex composed of eight Bardet-Biedl syndrome (BBS) proteins including BBS1, has emerged as an important regulator of various cellular processes. The similarity in the phenotypes evoked by disruption of the BBSome and mitochondria function led us to hypothesize that the BBSome plays an important role in the regulation of mitochondria dynamics and function. To test this, we used a multidisciplinary approach that include CRISPR/Cas9 technology-mediated generation of stable Bbs1 gene knockout cell lines (N39-BBS1KO and IMCD3-BBS1KO) and analysis of the phenotype of global and conditional BBSome deficient mice. Disruption of the BBSome caused mitochondria hyperfusion in cell lines, fibroblasts derived from BBS patients as well as in hypothalamic neurons and brown adipocytes of mice. The morphological changes in mitochondria translate into functional abnormalities as indicated by the altered mitochondrial distribution, reduced oxygen consumption rate and calcium handling responded to PDGFbb stimulation (340/380 ratio, cytosolic Ca2+ 44.0±,5.4 in N39 cells vs 19.5±3.0 in N39-BBS1KO cells, and mitochondria Ca2+, 75.7±4.4 in N39 cells vs11.8±2.1 in N39-BBS1KO cells, P<0.01). Mechanistically, we found that absence of the BBSome caused ~25% decrease (P<0.01) in phosphorylation at Serine 616 site of dynamin-like protein 1 (DRP1), a key regulator of mitochondrial fission. Notably, rescuing the decrease in DRP1 activity through deletion of one copy of the gene encoding A-kinase anchoring protein 1 (AKAP1) was effective to normalize the defects in mitochondrial morphology and DRP1 activity induced by BBSome deficiency. Importantly, this was associated with improvement in several of the phenotypes caused by loss of the BBSome such as the neuroanatomical abnormalities including motile cilia morphology and hydrocephalus. Loss of AKAP1 also rescued the obesity phenotype as indicated by the reduced body weight (35.4±1.6 in males, 30.5±1.5g in females) relative BBS mice (40.6±1.6 g in males, 32.3±1.5g in females, P<0.05). These findings demonstrate a critical role of the BBSome in the modulation of mitochondria and point to mitochondrial defects as a key disease mechanism in BBS.

NIH RO1 and VA for K.R

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.
Neutrophil developmental defects cause hyperinflammation in cherubism
Authors: Cao Ziming , Karlinsey Keaton , Sah Shyam Kishor , Flynn William , Reichenberge Ernst , Zhou Beiyan , Chen I-Ping , Fan Zhichao
Published: May 2023

Cherubism is a rare autosomal dominant disease caused mainly by a P416R point mutation of Src homology 3 Domain Binding Protein 2 (SH3BP2). Though macrophages and osteoblasts were thought to be the major contributors to the pathology in the past, the involvement of neutrophils in cherubism has been demonstrated by the increasing neutrophil infiltration and extensive neutrophil extracellular trap formation in the lesion recently. Here, we observed decreased expression of lineage marker Ly6G and impaired integrin activation on neutrophils, indicating a developmental defect of neutrophils in cherubism mice carrying the SH3BP2 P416R mutation. Furthermore, we performed single-cell RNA sequencing and compared transcriptomes between blood neutrophils, bone marrow neutrophils, and bone marrow leukocyte progenitors from wildtype and SH3BP2 P416R mice. RNA velocity and pathway analysis show that mutated neutrophils have stalled in the early stage of neutrophil development and failed to mature into granzyme pathway-enhanced, NET-formation-restrained mature neutrophil population in wildtype. Together, our study first illustrates the neutrophil development defects in cherubism as a mechanism for hyperinflammation characterized in cherubism.

Ziming Cao and Keaton Karlinsey contributed equally. Beiyan Zhou, I-Ping Chen and Zhichao Fan are co-corresponding authors. This research was supported by grants from the National Institutes of Health, National Heart, Lung, and Blood Institute, USA (R01HL145454), and a startup fund from UConn 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.
AAV-driven expression of channelrhodopsin-2 in lingual myofibers enables light activation of lingual electromyogram activity
Authors: Singer Michele , Benevides Ethan , Rana Sabhya , Martinez Robert , Barral Brian , Sunshine Michael , Byrne Barry , Fuller David
Published: May 2023

Contraction of the tongue muscles is needed for effective swallowing, speaking and breathing. Thus, inadequate tongue muscle activation can contribute to devastating conditions such as dysarthria, dysphagia, and obstructive sleep apnea. Existing treatments for these clinical conditions are often ineffective and/or poorly tolerated. Optogenetic technology allows for exceptional temporal and spatial precision for stimulating cells and may therefore provide a tool activating the tongue muscles to promote airway patency or enhance swallow function. The purpose of the current study was to test the hypothesis that lingual injection of an AAV9 vector encoding channelrhodopsin-2 (ChR2) would enable light-induced activation of tongue motor units during spontaneous breathing. An AAV9 vector (pACAGW-ChR2-Venus-AAV9, 8.29E11vg) was injected into the posterior tongue in adult C57BL/6Jmice, targeting the genioglossus. After 12 weeks, mice were anesthetized and posterior tongue electromyographic (EMG) activity was recorded during spontaneous breathing. Photostimulation of the tongue was achieved using a high-powered 473 nm light emitting diode positioned near the injection site. Single pulse as well as pulse train stimulation paradigms of varied intensity and duration were performed. Light-evoked EMG responses increased with the intensity (1-way ANOVA on ranks, p=0.002) and duration (1-way ANOVA on ranks, p<0.001) of single light pulses. Trains of light pulses were able to evoke lingual EMG bursts that were comparable to endogenous tongue muscle activation with XII nerve intact. Experiments were repeated after bilateral transection of XII nerve, and light stimuli were still effective at activating lingual EMG. Histology confirmed lingual myofiber transgene expression that was concentrated near the site of AAV injection. These experiments demonstrate the feasibility of using optogenetic stimulation to activate tongue musculature. This novel approach could potentially have application in clinical conditions in which reduced lingual muscle activity is problematic.

2R01HD052682-11A1 (DDF, BJB), MBI Graduate Fellowship Award (MLS)

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 neural basis for fasting activation of the hypothalamic-pituitary adrenal axis
Authors: Resch Jon , Douglass Amelia , Madara Joseph , Kucukdereli Hakan , Yizhar Ofer , Grama Abhinav , Yamagata Masahito , Yang Zongfang , Lowell Bradford
Published: May 2023

Fasting initiates a multitude of adaptations to allow survival. Activation of the hypothalamic-pituitary-adrenal (HPA) axis and subsequent release of glucocorticoid hormones is a key response that mobilizes fuel stores to meet energy demands. Despite the importance of the HPA axis response, the neural mechanisms that drive its activation during energy deficit are unknown. Here, we show that hypothalamic agouti-related peptide (AgRP)-expressing neurons trigger and are essential for fasting-induced HPA axis activation. AgRP neurons stimulate activity of the HPA axis via projections to the paraventricular hypothalamus (PVH), where, in a mechanism not previously described for AgRP neurons, they presynaptically inhibit the terminals of tonically active GABAergic afferents from the bed nucleus of the stria terminalis (BNST) that otherwise restrain activity of corticotrophin-releasing hormone (CRH)-expressing neurons. This disinhibition of PVH-Crh neurons requires GABA (γ-aminobutyric acid)/GABA-B receptor signaling and potently activates the HPA axis. Importantly, stimulation of the HPA axis by AgRP neurons is independent of their induction of hunger, showing that these canonical ‘hunger neurons’ drive multiple parallel adaptations to the fasted state. Together our findings identify the neural basis for fasting-induced HPA axis activation and uncover a unique means by which AgRP neurons activate downstream neurons – via presynaptic inhibition of GABAergic afferents. Given the potency of this disinhibition of tonically active BNST afferents, other activators of the HPA axis such as psychological stress may work via a similar mechanism.

NIH R01DK096010, NIH R00HL144923, AHA 935362

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.
Airway inflammation and cough hypersensitivity induced by tumor necrosis factor alpha in mice
Authors: Lee Lu-Yuan , Lee Lu-Yuan , Lin Ruei-Lung , Lin An-Hsuan , Athukorala Ashami , Khosravi Mehdi
Published: May 2023

Tumor necrosis factor alpha (TNFα), a pro-inflammatory cytokine, plays a significant role in the pathogenesis of asthma and bronchial hyperrresponsiveness. We have previously reported that TNFα pretreatment elevated the sensitivities of vagal bronchopulmonary C-fibers to chemical irritants in mice (Lin et al., Front Physiol 8: 411, 2017). More recently, we have demonstrated that inhalation of sulfur dioxide (SO2), a common irritant gas and a major industrial air pollutant, can elicit cough by activating these bronchopulmonary C-fibers (Lin et al., J Physiol 585: 1093-1108, 2020). Based upon these previous findings, we carried out this study to test the hypothesis that the cough response to inhaled SO2 is enhanced by pretreatment with TNFα. Coughs were recorded via a telemetry sensor implanted in the intra-pleural space in awake mice moving freely in a recording chamber. Our results showed: 1) Intra-tracheal instillation TNFα (10 μg/ml; 0.03 ml) into the lung induced airway inflammation 24 h later, as shown by 2.9-fold increase in the total leukocyte count in the bronchoalveolar lavage fluid, and 12.8- and 28.4-fold increases in the percentages of eosinophils and neutrophils, respectively, compared to vehicle-treated mice. 2) The TNFα pretreatment significantly elevated the cough responses to SO2 inhalation challenges (300 and 600 ppm, 8 min) in the same animals; e.g., the average cough frequencies during the SO2 (600 ppm) inhalation were 1.1 ± 0.2 and 3.1 ± 1.0 (min-1; n=7, P<0.05) before and three days after the TNFα pretreatment, respectively. This TNFα-induced increase in cough sensitivity slowly declined toward the baseline after 6-8 days. 3) The same TNFα pretreatment did not cause any significant increase in cough responses to SO2 inhalation challenges in p55/p75 (TNF receptors)-null mice. Pretreatment with the vehicle of TNFα (0.03 ml of PBS) also failed to induce cough hypersensitivity to inhaled SO2 in wild-type mice. In conclusion, intra-tracheal instillation of TNFα induced airway inflammation and a long-lasting elevation of cough responses to inhaled SO2. This action of TNFα was mediated through the activation of TNF receptors.

NIH grants AI123832 and ES026529-04S1, and Merck MISP100107

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.
Iron controls lung fibroblast activation and invasion via SH3RF1/HIPK2 pathway
Authors: Huang Chaoqun , Dang Quanjin , Liang Yurong , Hewawasam Sankha , Liu Lin
Published: May 2023

Iron is a metal element indispensable for nearly all living organisms, as it participates in a variety of biological processes. The homeostasis of iron is essential to human health. Iron-responsive element-binding proteins (IRP1 and IRP2) bind the iron-responsive element (IRE) of mRNAs to control mRNA stability or protein translation. Abnormal iron homeostasis can lead to a broad spectrum of human diseases. The objective of this study was to investigate the role and mechanism of iron in lung fibroblast activation. We hypothesize that iron overload enhances lung fibroblast activation via the SH3 domain containing ring finger 1 (SH3RF1)/homeodomain interacting protein kinase 2 (HIPK2) pathway. Search for iron-responsive elements (SIREs) software was employed to predict IREs in human and mouse genomes. Lung fibroblast function studies were performed by determining the expression of myofibroblast marker α-smooth actin (α-SMA) using real-time PCR, Western blotting, and immunostaining and analyzing fibroblast invasion. Iron supplementation with ferric ammonium citrate (FAC) enhanced the mRNA and protein expression of α-SMA and fibroblast invasion. SH3RF1 was found to contain a novel IRE in its 3’-UTR and was down-regulated by iron treatment. Overexpression of SH3RF1 suppressed the iron-induced lung fibroblast activation. Moreover, iron treatment enhanced the expression of HIPK2 protein in lung fibroblasts, which was reduced by SH3RF1 overexpression. Knockdown of HIPK2 protein inhibited α-SMA mRNA expression. Furthermore, treatment of the lung fibroblasts with MG132 increased HIPK2 protein level, which was suppressed by SH3RF1 overexpression. In summary, iron controls lung fibroblast activation and invasion via the SH3RF1/HIPK2 regulation system and may be involved in the pathogenesis of idiopathic pulmonary fibrosis.

R01 HL157450, R01HL135152 and P20GM103648

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.
Cell-free hemoglobin-mediated oxidation of low-density lipoprotein (oxLDL) contributes to lung microvascular endothelial dysfunction during sepsis
Authors: Meegan Jamie , Ware Lorraine , Bastarache Julie
Published: May 2023

Introduction: Disruption of the microvascular endothelial barrier is a critical pathological feature of sepsis-induced acute lung injury. Plasma cell-free hemoglobin (CFH) is elevated in approximately 80% of patients with sepsis and is independently associated with development of acute respiratory distress syndrome (ARDS) and mortality. Oxidized CFH (ferric, 3+) can oxidize low-density lipoprotein (oxLDL), which signals through its major endothelial receptor, the lectin-like oxidized LDL receptor 1 (LOX-1), to cause endothelial dysfunction through several pro-inflammatory pathways including activation of mitogen-activated protein kinases (MAPKs). However, little is known regarding whether LOX-1 receptor signaling leads to microvascular endothelial hyperpermeability or acute lung injury, especially in the context of sepsis. We hypothesized that oxidation of LDL by CFH contributes to lung microvascular endothelial barrier dysfunction and worse outcomes during sepsis through LOX-1 and downstream p38 MAPK. Methods: To test whether generation of oxLDL by CFH is associated with endothelial injury in clinical sepsis, circulating levels of CFH, oxLDL, and vascular injury marker sVE-cadherin were measured in 24 sepsis patients via ELISA and tested for association with development of ARDS. LDL was oxidized by combining LDL with CFH in a test tube overnight at 37°C and oxLDL was quantified by TBARS assay. In primary human lung microvascular endothelial cells (HLMVEC) transendothelial electrical resistance (TER), a measure of barrier dysfunction, was assessed by Electric Cell-substrate Impedance Sensing (ECIS). LOX-1 receptor was blocked using BI-0115 (Boehringer Ingelheim, 20 μM) and p38 MAPK was inhibited using NiPp (100 μM). Results: In sepsis patients, plasma oxLDL levels correlated with CFH (r=0.686, p=0.016) and sVE-cadherin (r=0.603, p=0.012), and tended to be higher in those who developed ARDS (38 U/L [IQR 27, 45] vs. 27 U/L [IQR 19, 35], p=0.1). Oxidation of LDL by CFH exacerbated HLMVEC barrier dysfunction compared to control, LDL, or CFH. Barrier dysfunction induced by CFH or oxLDL was attenuated by blocking the LOX-1 receptor or p38 MAPK. Conclusions: Increased plasma CFH and oxLDL are associated with vascular injury during clinical sepsis; one mechanism by which CFH may cause vascular hyperpermeability and sepsis-mediated lung injury is through oxidation of LDL which can drive signaling through the endothelial LOX-1 receptor and activation of p38 MAPK.

NIH R35HL150783, R21GM144915, R01HL158906, R01HL164937, T32HL094296; Parker B. Francis Fellowship

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.
Fatty acid-binding proteins promote endothelial glycolysis and arterial programming in pulmonary arterial hypertension
Authors: Dai Zhiyu , Liu Bin , Yi Dan , Hamid Syed , Kala Mrinalini , Glembotski Chris , Fallon Michael
Published: May 2023

Introduction: Pulmonary arterial hypertension (PAH) is a disaster disease characterized by obliterative vascular remodeling and persistent increase of vascular resistance, leading to right heart failure and premature death. Understanding the cellular and molecular mechanisms will help develop novel therapeutic approaches for PAH patients. Hypothesis: We hypothesis that endothelial fatty acid metabolism is critical for obstructive vascular remodeling in the pathogenesis of PAH. Methods: A severe mouse model of PH Egln1Tie2Cre mice were bred with Fabp45-/- mice to generate Egln1Tie2Cre/ Fabp45-/- mice. Single-cell RNA sequencing (scRNA-seq) analysis and metabolomic analysis were used to profile the pulmonary cells in Egln1Tie2Cre mice and Egln1Tie2Cre/ Fabp45-/- mice. Human hPAEC from idiopathic PAH patients and healthy donors, monocrotaline (MCT)-induced and Sugen5416/hypoxia (SuHx)-induced PH rats were used to measure fatty acid-binding protein 4 and 5 (FABP4 and FABP5) expression. siRNA mediated knockdown of FABP4 and FABP5 and lentivirus mediated FABP4 and 5 overexpression were performed to study cell proliferation, apoptosis, glycolysis, fatty acid oxidation. Echocardiography, hemodynamics, histological and immunostaining assay were performed to evaluate the PH phenotypes. Results: Both FABP4 and 5 were highly induced in the ECs of Egln1Tie2Cre mice and PAECs from IPAH patients, as well as the whole lungs of MCT and SuHx-induced PH rats. Knockdown or overexpression of FABP4-5 reduced or enhanced EC proliferation, starvation-induced Caspase 3/7 activity, glycolysis and fatty acid oxidation. Genetic deletion of Fabp4 and 5 in Egln1Tie2Cre mice exhibited a reduction of right ventricular systolic pressure (RVSP), RV hypertrophy, and attenuation of pulmonary vascular remodeling, prevention of right heart failure. Fabp4-5 deletion also normalized EC glycolysis and arterial gene programming, reduced HIF-2a expression and endothelial proliferation in Egln1Tie2Cre mice. Conclusions: FABP4 and 5 control EC glycolysis and arterial programming and contribute to the development of severe PH.

This work was supported in part by NIH grants R00HL138278, R01HL158596, American Heart Association Career Development Award 20CDA35310084, American Thoracic Society Foundation and Pulmonary Hypertension Association Research Fellowship, The Cardiovascular Medical and Education Fund, Arizona Biomedical Research Centre funding (ADHS18-198871), and University of Arizona Startup funding to Z. Dai

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.
Morphology of neuromuscular junction in patients with peripheral artery disease
Authors: Tu Huiyin , Kim Julian , Hakim Ali , Zhu Zhen , Pipinos Iraklis , Li Yulong
Published: May 2023

Peripheral artery disease (PAD) is primarily caused by occlusion of arteries that supply blood to the lower limbs and presents significantly pathological changes of calf muscles, include degenerating and regenerating fibers, reduction of the skeletal muscle area, connective tissue proliferation and fibrosis, fat accumulation, and abnormal mitochondria, all of which are predictors of muscle functional decline. Additionally, skeletal muscles also require the motor nerve innervation for the signal transmission through the neuromuscular junction (NMJ) to induce skeletal muscle contraction. To observe whether the NMJ is changed in the PAD patients, gastrocnemius muscles were collected from 2 health subjects and 6 PAD stage III/IV patients. The motor nerve terminals were labeled with anti-neurofilament 200 and anti-synaptophysin antibodies, the nicotinic acetylcholine receptors (nAChRs) were labeled with α-Bungarotoxin. Labeled NMJs were imaged using a laser scanning confocal microscope with Z-stack. The image was captured in 65 NMJs from health subjects and 140 NMJs from PAD patients, respectively. The total nAChR area and the number of discrete fragments of each nAChR cluster, the area per fragment, the percentage of fragmented nAChR clusters, the nerve innervation and the nerve terminal occupancy were calculated. The results were represented with mean ± standard error (SE). The nAChR area was 354.9 ± 12.7 and 209.4 ± 8.2, the average number of fragment/ nAChR cluster was 2.6 ± 0.2 and 3.1 ± 0.2, 6.2% and 19.3% of the nAChR clusters were fragmented, and the nerve terminal occupancy was 61.5 ± 1.4 % and 52.0 61.5 ± 1.8 in the health subjects and PAD patients, respectively. All nAChR clusters were innervated by the motor nerve terminal in the health subjects, whereas 8.6% of nAChR clusters were denervated in PAD Patients. These data indicate that the total nAChR area per nAChR cluster and the area of each discrete fragment are reduced and fragmented nAChR clusters are increased in PAD patients. Additionally, the denervation of nAChR clusters is increased in PAD patients. These results suggest that the neuromuscular transmission is compromised in PAD patients, which limits patients’ physical activities.

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 Mfge8 in the reduced contractility of diabetic gastroparesis
Authors: Dutcher Dustin , Perrino Brian
Published: May 2023

Coordinated gastric contractility is imperative for ideal digestion and absorption of nutrients. This is impaired during diabetic gastroparesis, a disorder characterized by abnormal gastric smooth muscle contractions leading to delayed gastric emptying. The objective of this research was to further the understanding of the gastric smooth muscle contraction regulatory mechanisms and how these cascades are affected by diabetes. In addition to its anti-inflammatory properties, it has been shown that milk fat globule-epidermal growth factor 8 (Mfge8) binding to ɑ8β1 integrin decreases murine gastric contractile activity by reducing the inhibitory phosphorylation of MLCP, resulting in MLCP activation and reduced myosin phosphorylation. Additionally, Mfge8 is elevated in human serum from type 2 diabetic individuals compared to non-diabetic individuals. It is hypothesized that elevated levels of Mfge8 in smooth muscle tissue will lead to decreased contractility strength, a phenomenon that would resemble gastroparesis secondary to diabetes. We analyzed the contractility and Mfge8 expression of human gastric antrum smooth muscles from obese diabetic and obese non-diabetic individuals who elected to undergo sleeve gastrectomy surgery for weight loss. Short strips of gastric muscle were stimulated to contract with serial concentrations of carbachol and contractile activity was measured with AcqKnowledge software. Mfge8 protein expression was then analyzed using a Wes Simple western instrument. We report that human gastric antrum smooth muscle tissue levels of Mfge8 are elevated in diabetic obese individuals (n=22) compared to non-diabetic obese individuals (n=37, P=0.004). However, we show that the contractile activity of antrum smooth muscle from diabetic obese individuals (n=38) is not dependent on Mfge8 levels and is not significantly different from the contractility of non-diabetic obese individuals (n=38). The rate of contraction, rate of relaxation, and overall tension ( P=0.40) produced by the muscle tissues from the two groups did not significantly differ from each other. It is possible that Mfge8 was not elevated enough to cause reduced contractility, or that those with elevated Mfge8 had not yet developed symptoms of gastroparesis. Mfge8 may serve as a biomarker for diabetic gastroparesis in the future, and additional research is required to determine the pathologic significance of elevated Mfge8 levels in obese diabetic human gastric antrum smooth muscle.

This research was supported by a National Institute of Diabetes and Digestive and Kidney Diseases Diabetic Complications Consortium (DiaComp, http://www.diacomp.org ) Grant DK076169, a Takeda Pharmaceuticals Innovation Center Grant to BP, and a UNRSOM Office of Medical Research Grant FD110-PG08935 to DD.

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.
Bacillus subtilis 67989 improves endothelial-mediated dilation in male mice fed a western diet
Authors: Risk Briana , Graham Elliot , Brown Gabriele , Stark Grace , Zhang Mingye , Hinkle Kayla , Wei Yuren , Weir Tiffany , Gentile Christopher
Published: May 2023

The gut microbiota has emerged as a novel regulator of vascular function. We have shown that targeting the microbiota can improve endothelial dysfunction in the settings of nutrient excess and obesity. In a previous clinical trial, intake of the spore-forming bacteria Bacillus subtilis was associated with improved markers of endothelial function in healthy adults. Here we examined whether consumption of Bacillus subtilis 67989 reverses endothelial dysfunction in a diet-induced obesogenic mouse model. Male C57/BJ mice were fed a Western diet (WD; n=24) or standard diet (SD; n=24) for 10 weeks, then further subdivided for an additional 9-12 weeks such that half (n=12) of all mice received B. subtilis 67989 (PB) formulated into the diets, thus yielding 4 experimental groups (WD, SD, WD+PB, SD+PB). After the dietary intervention, both WD-fed cohorts exhibited significant increases in body weight, glucose intolerance, markers of intestinal inflammation and alterations in gut microbiome composition, with no effect of PB. Endothelium-dependent dilation was impaired in WD vs SD (60.6±6.5% vs 85.3±3.8%, respectively p<0.05), whereas this impairment was mitigated in WD+PB (77.5±3.2%) such that dilation was not significantly different than SD-fed mice. In conclusion, the probiotic Bacillus subtilis 76989 attenuates obesity-related endothelial dysfunction in male mice independent of changes in body weight or glucose intolerance. Current analyses are examining putative mechanism(s) that mediate this improvement.

National Heart, Lung, and Blood Institute Grant R01-HL-144611-01 (to C. L. Gentile and T. L. Weir)

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.
Acute hyperglycemia lowers endothelial TRPV4 channel activity
Authors: Kulshrestha Astha , Chen Yen-Lin , Sonkusare Swapnil
Published: May 2023

Calcium signaling mechanisms regulate endothelium-dependent dilation of small arteries. Endothelial dysfunction has been linked to the clinical symptoms observed in diabetic patients, although the underlying mechanisms behind compromised endothelial health are unclear. The clinical symptoms of hyperglycemia are exacerbated in diabetic patients due to their higher initial spike in blood glucose concentration after food intake. However, the effects of acute increases in glucose levels on endothelial calcium signals have not been studied. Recent studies indicate that transient receptor potential vanilloid 4 (TRPV4) channels, a calcium entry pathway in endothelial cells, promote the dilation of small arteries. Therefore, we hypothesized that hyperglycemia lowers endothelial TRPV4 channel activity to impair the dilation of small arteries. The calcium signal activity of endothelial cells (ECs) was compared in small mesenteric arteries (MA, ~ 100 μm) from C57BL6J mice under normal (5 mM Glucose) and hyperglycemic (25 mM Glucose) conditions using spinning disk confocal microscopy. En face MAs were loaded with fluo-4 AM (10 μM) and images were acquired at 30 frames per second to capture real-time changes in calcium signals. The baseline activity of endothelial calcium signals was lower under hyperglycemic conditions compared to normal and osmotic control (5 mM Glucose/20 mM Mannitol) conditions. In the presence of TRPV4 channel inhibitor GSK2193874 (GSK219, 100 nM), hyperglycemia-induced decrease in endothelial calcium signals was abolished, suggesting that hyperglycemic conditions target endothelial TRPV4 channels. To verify this possibility, we recorded the activity of endothelial TRPV4 channels as unitary calcium influx signals, called TRPV4 sparklets, in the presence of cyclopiazonic acid to eliminate the interference from intracellular calcium release signals. TRPV4 channels were activated using GSK1016790A (GSK101, 3 nM), a selective channel activator. The number of TRPV4 sparklet sites and activity per site were both reduced under hyperglycemic conditions compared to normal conditions. Overall, these data suggest that acute hyperglycemia reduces the activity of endothelial TRPV4 channels, which may attenuate endothelial function. Future work will determine the acute contribution of hyperglycemia-induced decrease of TRPV4 channel activity to impaired endothelium-dependent vasodilation.

This work was funded by grants from the NIH (HL142808 and HL147555) to Dr. Sonkusare.

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.