bluuebunny/crossref_metadata_2025_split huggingface dataset:
CysLT1R is essential for optimal TLR4 responses and associated macrophage polarization and sepsis in response to LPS
Authors: Teegala Lakshminarayan Reddy , Pokhrel Sabita , Sabu Kattuman Emma Elizabeth , Gudneppanavar Ravindra , Thodeti Charles , Paruchuri Sailaja 
Published: May 2023

Background: Cysteinyl leukotrienes (cys-LTs; LTC4, LTD4 and LTE4) are arachidonic acid-derived inflammatory lipds, acting mainly via two G-protein-coupled receptors (GPCRs), cysteinyl leukotriene receptor 1 (CysLT1R) and cysteinyl leukotriene receptor 2 (CysLT2R). Cys-LTs are mainly recognized as potent modulators of asthma and allergy with their effects on mast cells. However, their role in other pathophysiological conditions are not well understood. Higher amounts of cys-LTs were reported in the lungs of mice subjected to sepsis than compared to sham mice, suggesting that CysLTs play critical role in sepsis via modulation of macrophage inflammatory responses. Objective: To investigate how cys-LT/CysLTR axis determines the inflammatory fate of macrophages in LPS/TLR4-induced sepsis. Methods: Bone marrow-derived stem cells (BMSC) from wild type (WT) and CysLT1R null ( Cysltr1-/-) mice were differentiated into macrophages and polarized to inflammatory phenotype using LPS via TLR4 pathway. Transcript and protein expression was analyzed by qPCR/RNA seq and western blotting/multiplex ELISA respectively. Results: LPS/TLR4 axis polarized WT macrophages to inflammatory phenotype by activating inflammatory intracellular signals (p38, CREB, and NFkB), upregulating surface expression of inflammatory markers (CD68, CD11b and LFA-1), enhancing phagocytosis and augmenting inflammatory cytokine secretion, in vitro. In contrast, LPS treated Cysltr1–/– macrophages exhibited attenuated TLR4 signaling observed with WT mice, suggesting that inhibition of CysLT1R prevents optimal TLR4 activation in response to LPS. Notably, reporter assays revealed a strong interaction between TLR4 and CysLT1R in HEK blue TLR4 cells overexpressing CysLT1R, further emphasizing a potential CysLT1R-TLR4 cross talk in driving TLR4-dependent inflammatory macrophage phenotype. Finally, Cysltr1–/– mice were protected from LPS-induced sepsis compared to WT mice with comcomitant reduction in the production of inflammatory cytokines. Conclusions: Our results uncover a potential crosstalk between two important innate immune receptors, TLR4-CysLT1R, in mediating macrophage inflammatory phenotype and sepsis in vivo. Understanding this interaction may offer novel potential therapeutic targets for macrophage-associated inflammatory disorders like sepsis. This work was supported by National Institutes of Health (R01AI144115 and R01HL148585) 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.
Intestinal epithelial transcription factor HNF4A protects against microbiota dependent colitis and expansion of Akkermansia muciniphila
Authors: Rawls John , Kelly Cecelia , Jawahar Jayanth , Davey Lauren , Everitt Jeffrey , Galanko Joseph , Anderson Chelsea , Avendano Jonathan , McCann Jessica , Sartor Ryan , Valdivia Raphael 
Published: May 2023

Development of the inflammatory bowel diseases (IBD) has been linked to altered homeostatic relationships between the intestine and the microbiota it harbors. However early preclinical stages of IBD remain poorly understood, especially with respect to host-microbiota interactions. The nuclear receptor transcription factor Hepatocyte nuclear factor 4 alpha (HNF4A) has important roles in intestinal epithelial cell (IEC) physiology, and our recent studies in zebrafish and mice revealed that HNF4A activity in IEC is suppressed by intestinal microbiota. Variants at HNF4A have been associated with human IBD, and IEC-specific knockout of Hnf4a in mice ( Hnf4a ΔIEC) leads to spontaneous colonic inflammation by 6-12 months. We hypothesized that intestinal pathology in Hnf4a ΔIEC mice may begin earlier in life and that microbiota may contribute to that process. Longitudinal analysis revealed that Hnf4a ΔIEC mice reared in specific pathogen-free (SPF) conditions develop fecal lipocalin 2 (LCN2) flares and episodic loose stools beginning as early as 4-5 weeks of age. Lifetime cumulative LCN2 levels correlated with histopathological features of colitis at 12 months of age. Antibiotic and gnotobiotic tests showed that these phenotypes in Hnf4a ΔIEC mice were dependent on the presence of microbiota. Fecal 16S rRNA gene sequencing in an SPF cohort of Hnf4a ΔIEC mice and controls at 12 months of age disclosed that genotype was a significant contributor to alterations in microbiota composition. Longitudinal analysis in a subset of inflamed Hnf4a ΔIEC and wild-type mice revealed that microbial community differences emerged at early life stages when fecal LCN2 flares first arose. These microbiota differences included a salient increase in the relative abundance of Akkermansia muciniphila in a subset of Hnf4a ΔIEC mice. We isolated an A. muciniphila strain from an aged, inflamed Hnf4a ΔIEC mouse, and its genome sequence revealed it to be a member of a new Akkermansia phylogroup with genetic features distinct from the known phylogroups. We conclude that HNF4A functions in IEC throughout the lifespan to protect against episodic flares of inflammation induced by microbiota while also shaping microbiota assembly. These results establish Hnf4a ΔIEC mice as a useful model for investigating preclinical pathology and host-microbiota interactions that precede overt IBD onset. NIH P01-DK094779 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.
Wet-Bulb Temperature or Heat Index: Which Better Predicts Fatal Heat in a Warming Climate?
Authors: Lu Yi-Chuan , Romps David 
Published: May 2023

The wet-bulb temperature of 35 °C has been widely used as the threshold for human survivability in the field of climate science. However, recent experiments have shown that a person's core temperature starts to rise at a range of critical wet-bulb temperatures well below this threshold. It is shown here why this state of severe heat stress cannot be predicted using the wet-bulb temperature. Instead, it is shown that the recently extended heat index can explain nearly all of the variance in the observed critical combinations of temperature and humidity in those heat-stress experiments. For light and moderate exertion in an indoor setting, the heat index predicts that the critical wet-bulb temperature ranges from 20 to 32 °C, depending on the relative humidity, consistent with experimental results. For the same setting and exertion, the heat index predicts fatal wet-bulb temperatures ranging from 24 to 37 °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.
Renoprotection conferred by empagliflozin in heart failure is associated with M2 macrophage polarization
Authors: Wisnivesky Aline , Bertacchi João Guilherme , Girardi Adriana 
Published: May 2023

Background: SGLT2 inhibitors, primarily developed as antidiabetic agents, exert beneficial effects on the heart and kidneys beyond glucose control. We have previously demonstrated that the prevention of heart failure (HF) progression in rats by the SGLT2 inhibitor empagliflozin (EMPA) is associated with reduced proximal tubule NHE3 activity, restoration of euvolemia, and preservation of renal mass. The present study was undertaken to test the hypothesis that empagliflozin alleviates kidney injury in heart failure by eliciting anti-inflammatory responses. Methods: Male Wistar rats were subjected to myocardial infarction or sham operation. After four weeks, rats that developed HF and sham rats were treated with EMPA (10 mg/kg/day) or not for an additional four weeks, resulting in 4 experimental groups: [Sham (n=8) and Sham+EMPA (n=8), HF (n=10), HF+EMPA (n=9)]. The glomerular filtration rate (GFR) was estimated by creatinine clearance. Histological analysis was performed to evaluate renal congestion and tubular atrophy. Immunohistochemistry and quantitative RT-PCR were performed to assess inflammatory markers. Results are reported as the mean ± standard error of the mean. Comparisons among the means were conducted using a two-way variance analysis (ANOVA) followed by Tukey's post hoc test. P<0.05 was considered significant. Results: Untreated HF rats exhibited lower GFR and kidney weight to tibia length ratio than the Sham. EMPA treatment preserved GFR and renal mass and markedly attenuated HF-induced kidney congestion and tubular atrophy. There was a similar elevation in the number of pan-macrophage marker CD68-positive cells in the kidneys of untreated and EMPA-treated HF rats compared to Sham groups. However, EMPA-treated HF rats displayed downregulation in the kidney mRNA expression levels of M1 macrophage polarization markers (TNFα, iNOS, and CCR2) and upregulation of M2 macrophage polarization markers (CD206, Arg-1, and CD163) compared to untreated HF animals. Additionally, HF+EMPA rats displayed reduced renal infiltration of CD3+ T cells per field compared to untreated HF rats (21±3 vs. 12±1, P<0.01). Conclusion: These results suggest that empagliflozin alleviates renal injury in cardiorenal syndrome. This renoprotective effect may be attributable at least partially to the activation of anti-inflammatory pathways that modulate macrophage polarization. FAPESP 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.
Endothelial expression of iron transporters is dependent on contact with smooth muscle
Authors: Dunaway Luke , Luse Melissa , Isakson Brant 
Published: May 2023

Iron is essential for heme-protein function. In the microcirculation, alpha hemoglobin is an important heme protein in endothelium and is essential for nitric oxide sequestration or production. In the endothelium, its expression is dictated by cellular contact with smooth muscle cells. Thus, we sought to determine if there was a similar contact dependency for iron import into endothelium. We did this initially by using our vascular cell co-culture model of primary human coronary endothelial cells (ECs) and smooth muscle cells (SMCs) in three conditions: 1. cultured without SMCs (monolayer ECs), 2. co-cultured without direct contact with SMCs (no-contact ECs), and 3. co-cultured with SMCs such that there is cellular contact with ECs (contact ECs). We then collected the ECs from each condition and performed bulk RNA sequencing for an unbiased screen of iron transporters. We found transferrin receptor 1 (TFRC) and divalent metal transporter 1 (SLC11A2) expression to be significantly increased in contact ECs compared to monolayer ECs. TFRC was also found to be significantly increased relative to no-contact ECs. This is important because both of these transport iron into cells. To determine if the contact dependency for iron import transporters was valid in vivo, we used mice with a YFP reporter on the Cdh5 Cre such that all endothelial cells could be analyzed from a particular tissue. Single cell RNA sequencing from mesenteric and adipose tissue was segregated into lymphatic, capillary, veinous and arterial endothelium. Similar to the contact co-culture, we found Tfrc and Slc11a2 to be enriched in arterial endothelium (where contact with smooth muscle is prevalent) as compared to any other endothelial cell type. Based on our data, we propose endothelial cell contact regulates iron import, which may be vital to alpha globin function. NIH HL088554 and University of Virginia Basic and Translational Research Training Grant T32 007284 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 myogenic program is enacted by cardiac protein CSRP3 in human and mouse kidney
Authors: Funahashi Yoshio , Nelson Jonathan , Burfeind Kevin , Munhall Adam , Groat Tahnee , Hutchens Michael 
Published: May 2023

Introduction: Cardiac injury with renal injury (acute cardiorenal syndrome) can induce renal fibrosis, but mechanisms by which heart injury signals to kidney are poorly understood. The myocardiocyte differentiation factor cardiac LIM protein (CSRP3) is released into plasma after cardiac injury, and taken up by megalin (Lrp2) in renal proximal tubular epithelial cells in vivo. We evaluated the relationship between cardiac injury and renal fibrosis in a mouse model and in human cells by characterizing novel primary culture of human tubular epithelial cells and then testing the hypothesis that CSRP3 alters PTEC transcription of myogenesis, transport, and extracellular matrix genes in vitro and in vivo. Methods: In mice, cardiac arrest (CA) was induced with potassium chloride and resuscitated with epinephrine and chest compressions (CPR) as previously described. SnRNAseq was conducted on mouse kidney cells harvested 24h after CA/CPR and analyzed using Seurat. Research-designated human kidneys were obtained under IRB exemption for non-human subjects research and underwent dissection, digestion and FACS sorting for PTEC selection. hPTEC were passaged up to 4x before transporters were characterized by qPCR, immunoblot, and immunofluorescence. Recombinant human CSRP3 (Origene) was administered to hPTEC followed by RNASeq and qPCR. CSRP3 (5μg) was retroorbitally injected in mice and renal fibrosis was assessed 7 weeks later. Results: In mice, snRNAseq demonstrated that CA/CPR significantly upregulated muscle cell differentiation ontologies in proximal tubule cells, driven by regulation of 110/162 myogenesis genes. Following FACS sorting for CD10 and CD13, hPTEC were 95% pure PTEC and expressed RNA and protein for PT transporters Lrp2, Aqp1, Slc34a1, and Slc5a2. In hPTEC, CSRP3 induced myogenesis differentiation factor 1 (MyoD1)>30 fold, and 20 myogenesis pathway and extracellular matrix genes. 8/20 genes were coordinately regulated between mouse kidney after CA/CPR and hPTEC after CSRP3. CSRP3 injection caused tubulointerstitial fibrosis in mice (VαSMA/Vkidney (%): 1.05 (CSRP3) vs 0.68 (control), n=8/group, p<0.01). Conclusion: hPTEC cultured from research-designated donor kidneys express a PT phenotype. The myocardiocyte differentiation factor CSRP3 causes transcriptional change in hPTEC, resulting in myogenic differentiation which is highly similar to that observed in mouse kidney after CA/CPR with coordinate regulation of myogenesis genes. Intravenous administration of CSRP3 to mice causes tubular interstitial fibrosis. Together these data strongly suggest CSRP3 may drive renal fibrosis via the myogenesis pathway. Merit grant I01BX004288-01 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Novel tools for neuronal activity, vessel diameter and red blood cell velocity imaging
Authors: Tiret Brice , Schuette Peter , Ollerenshaw Doug , Zitelli Kevin , Gulati Srishti , Adil Nosheen , Neufeld Shay , Nassi Jonathan 
Published: May 2023

Healthy brain function requires a delicate balance between neural activity and local vascular dynamics. Perturbations to this balance, such as vessel diameter changes or fluctuations in red blood cell velocity, are thought to underlie a number of neurodegenerative and neurovascular diseases, including migraine, stroke, and epilepsy. Here, for the first time, we demonstrate high fidelity simultaneous acquisition of vascular and neural circuit dynamics in freely-moving animals using our newly developed nVue dual color miniscope. Our system enables simultaneous imaging of blood flow and neural activity in both superficial and deep-brain structures in awake, behaving rodents. By multiplexing two LEDs at up to 100hz, the nVue enables direct, real-time visualization of both hemodynamics and calcium activity in two channels. Additionally, we have augmented the Inscopix Data Processing Software package to capture time-varying estimates of vessel diameter and red blood cell (RBC) velocity in specific vessels. Vessel diameter is estimated as the full-width half maximum of a Lorentzian function fit to vessel cross-section, while RBC velocity is calculated based on time-lagged correlations between seed-pixels within individual regions of interest and all immediately neighboring pixels. Distances between correlation peaks are then plotted against time. Manual annotation of blood flow data was performed to establish a ground truth against which to validate the algorithm. The nVue blood flow imaging application offers a powerful, turn-key, multisystem workflow for simultaneously interrogating hemodynamics and neural circuit function in freely behaving animals which will profoundly expand the neurovascular coupling toolkit not only for basic and translational research but also for the development of novel preclinical therapeutics. Commercial 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 Chronic Intermittent Hypoxia on Cognitive Function in Rats
Authors: Cheung Emily , Escobar Joan , Schunke Kathryn , Kay Matthew , Mendelowitz David 
Published: May 2023

Obstructive sleep apnea (OSA) affects approximately 2.2 million people worldwide and is characterized by frequent bouts of hypoxia during sleep, imbalance of the autonomic nervous system, and increased risk of cardiovascular diseases. Recent work has shown OSA is also strongly linked to cognitive impairments. In this study, we tested whether chronic intermittent hypoxia (CIH), an animal model of OSA, elicits anxiety and impairs learning and memory.Eight female adult Sprague Dawley rats were exposed to CIH (94% N2, 6% O2) for eight hours a day during their sleep cycle. Age matched controls were maintained under similar noise conditions, but at room air. After twenty-six weeks of CIH, learning skills were assessed. Using the Morris water maze protocol, animals were trained to swim to a visible platform in a circular pool. Animals underwent the training protocol for five consecutive days with six daily sessions. After training, animals were exposed to CIH for eight more weeks before tests were performed. During the testing session, spatial memory was tested by repeating the Morris water maze test with a hidden platform. In conjunction, anxiety levels were assessed using an open field maze test to quantify the duration of time an animal explores open regions on a platform.Animals exposed to CIH displayed significantly longer learning times (30.94 vs. 14.60 seconds, p < 0.0001, n=8) and lower levels of spatial recognition and memory (latency time 45.25 vs 27.33 seconds, p<0.05, n=8) than controls. Corresponding quantification of tau protein via ELISA demonstrated significant differences between the CIH and control groups (325.7 vs 206.1 pg/mL, p<0.05, n=8). Our results show, in an animal model of OSA, CIH impairs cognitive function. Future work will test if new treatment paradigms for OSA, such as oxytocin network activation, blunts decreases in cognitive abilities and increases in anxiety. NIH 5R01HL147279 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.
Mild hypoxia as therapy for post-ischemic mitochondrial injury
Authors: Piao Lin , Fang Yong-Hu , Wu Rongxue , Hamanaka Robert , Mutlu Gökhan , Archer Stephen , Garcia Alfredo , Sharp Willard 
Published: May 2023

Introduction: Mitochondrial injury occurs following cellular ischemia in the setting of myocardial infarction, stroke, and cardiac arrest (CA). Effective strategies for reducing injury are limited. Hypoxia has shown benefit in reversing mitochondrial mediated neurodegenerative disease but is little studied in the setting of post-ischemic injury and is regarded as potentially harmful. In this study, we investigated the effects of mild hypoxia on global post-ischemic injury following CA. We hypothesized that brief mild hypoxia following CA would improve mitochondrial function resulting in improved cellular metabolism and physiological recovery. Methods and Results: Anesthetized C57BL6 mice underwent brief asystolic CA (12 min) followed bycardiopulmonary resuscitation(CPR). One hour following successful CPR, mice were randomized to receive a brief episode (6 hours) of normoxia (21% O2) or hypoxia (10% O2) in an environmental chamber. Post intervention, the mice were returned to room air (21% O2). Mild hypoxia improved cardiac mitochondrial complex 1 respiration in the heart by 28% and ATP-related oxygen consumption by 49% (n=3, P<0.05 vs normoxia, respectively) compared to normoxia treated mice. Hypoxia was further associated with improved glucose oxidation in heart as evidenced by decreases in pyruvate dehydrogenase kinase 4 (PDK4) gene and protein expression (n=4, P<0.05 vs normoxia, respectively) as well as decreases in pyruvate dehydrogenase phosphorylation (n=4, P<0.05, respectively) in heart. Hypoxia decreased lactate dehydrogenase (LDH) expression and lactate concentration in heart compared to normoxia treated controls (n=4, P<0.05 vs normoxia, respectively). ROS production in heart by 20% (n=6, P<0.05) was also decreased by mild hypoxia when compared to normoxia post CA. These changes were associated with improved recovery of myocardial function, neurological recovery, and 10-day survival following CA (n=13, P<0.05 vs normoxia, respectively). Conclusion: Brief mild hypoxia treatment following global ischemic injury paradoxically improved recovery of myocardial mitochondrial respiration and metabolism and was associated with improved physiological recovery and survival. Post-ischemia hypoxia is a potential therapeutic strategy for mitochondrial ischemic injury and requires further study. No financial disclosures. 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.