bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diversity Outbred Mouse Model Recapitulates Human Heterogeneity in the Development of Western Diet-Induced Complications
Authors: Chittimalli Kishore , Tolle Andrew , Rahman Mansib , Jarajapu Yagna 
Published: May 2024

Background: Diet-induced obesity (DIO) increases risk for cardiovascular disease largely due to compromised gut barrier integrity and systemic inflammation. Animal models for understanding the pathophysiology of complications associated with DIO do not take address the genetic factors, which determine the individual variation in the susceptibility to develop complications. Hypothesis: DO mice recapitulate the heterogeneity of western diet-induced metabolic syndrome, gut barrier disruption and systemic inflammation. Methods: DO mice were fed with either control (CD) or western diet (WD) (Teklad) (n = 10) for 16 weeks. Blood glucose levels, glucose tolerance and the intestinal permeability were determined. Inflammatory cells in the bone marrow or blood were characterized in basal conditions or in response to hindlimb ischemia (HLI). Blood flow recovery following HLI was measured by using Laser Doppler Imaging system and the intestinal-stem-cells (ISCs) were characterized by using markers, Lgr5, Olfm4 and Wnt3. Results: Wide variation in the weight gain, hyperglycemia and glucose tolerance in DO mice was observed following WD (n = 10). Similarly, wide variation was observed in Wnt3 expression and in the density of ISCs in colon of DO mice on WD. Heterogeneity in the ISC layer correlated with the variation in the intestinal permeability induced by WD compared to the CD ( p < 0.05, n = 10). The number of inflammatory cells (monocytes – CD45+Ly6G−Ly6C+CD115+, neutrophils - CD45+Ly6G+Ly6C+CD115−, pro-inflammatory macrophages - CD45+CD11b+Ly6G−Ly6C+F4/80+CCR2+CD80+ and anti-inflammatory macrophages - CD45+CD11b+Ly6G−Ly6C+F4/80+CX3CR1+CD206+) in the BM or blood showed heterogeneity in WD-DO mice in accordance with variability in the glucose tolerance. Accordingly, blood flow recovery following HLI showed wide variation with three mice on WD showing full recovery, which correlated with variability in the mobilization of inflammatory cells (n = 9). Conclusion: DO mouse model depicts human diversity in response to WD-induced changes in gut barrier integrity, inflammation and ischemic vascular repair therefore serves as a suitable model for evaluating pharmacological agents that would be effective in a diverse population. Jackson Laboratory Diversity Outbred Pilot Award National Institute of Aging (AG056881). This is the full abstract presented at the American Physiology Summit 2024 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.
Sox9 links biliary maturation to branching morphogenesis
Authors: Hrncir Hannah , Bombin Sergei , Goodloe Brianna , Hogan Connor , Gracz Adam 
Published: May 2024

During liver development, bipotential epithelial progenitor cells, termed hepatoblasts, give rise to hepatocytes and biliary epithelial cells (BECs). BECs line the intrahepatic bile ducts which are essential for liver function. The adult intrahepatic bile duct (IHBD) network is hierarchical in structure with smaller, peripheral “ductules” draining into larger “ducts” that eventually exit the liver. Despite proposed models from histological and genetic studies, mechanisms differentiating local “duct” or “ductule” hierarchies and driving the global IHBD architecture are poorly understood. Previous studies of IHBD development have focused on mechanisms of BEC specification/ de novo bile duct formation by tubulogenesis. However, the contribution of pre-existing BECs to IHBD expansion and morphogenesis is unclear. Previous studies on liver specific Sox9 knockout (Sox9cKO) mice showed that Sox9 is important for timing of BEC specification during development and prevents cystogenesis in aged mice. We hypothesize that SOX9 is an important regulator of IHBD local and global architecture during development by promoting IHBD branching morphogenesis. Using whole-lobe 3D imaging and iDISCO+, we find that adult, embryonic, and postnatal Sox9cKO mice demonstrate ductal paucity with bias towards ductule, rather than duct, loss. Bulk RNA-sequencing reveals that Sox9cKO BECs are transcriptionally “immature” and have gene expression signatures consistent with a failure to fully acquire BEC identity. scRNA-sequencing identifies ductule-like cells in a subset of Sox9cKO BECs correlating with elevated Inhba, the gene precursor of Activin A. Sox9cKO biliary organoids exhibit non-cystic morphology that is reproduced in Activin A treated WT organoids. In vitro and in vivo, Activin A signaling inhibition experiments partially rescue BEC morphology. Together, our data demonstrate that SOX9 drives BEC maturation and promotes ductule formation, in part through inhibiting Activin A. Our data support a model for IHBD development involving distinct mechanisms governing Sox9-independent large duct tubulogenesis versus Sox9-dependent small ductule branching morphogenesis. F31DK134199; PI: Hannah Hrncir T34GM149511; PI: Anita Corbett, PhD; R01DK132653; PI: Adam Gracz, PhD. This is the full abstract presented at the American Physiology Summit 2024 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.
Loss of AC10 Impairs Neutrophil Recruitment and Alters Bacterial Colonization in the Lung During Bacterial Pneumonia
Authors: Stone Madeline , Choi Chung-Sik , Sayner Sarah 
Published: May 2024

Rationale: Pseudomonas aeruginosa is a gram-negative bacterium and a common cause of nosocomial pneumonia that can progress to acute respiratory distress syndrome (ARDS), characterized by hypoxia, pulmonary edema, elevated bicarbonate, and widespread inflammation. Neutrophil recruitment is a critical line of defense against P. aeruginosa; however, excessive, or dysregulated neutrophil infiltration can exacerbate tissue damage and contribute to the severity of ARDS. Recently, AC10 has been implicated in neutrophil transendothelial migration via CD99. Despite the growing recognition and significance of AC10 in various physiological processes, its role in neutrophil recruitment during ARDS remains poorly understood. Thus, herein we hypothesize that loss of AC10 attenuates neutrophil recruitment during pneumonia and increase bacterial colonization in the lung. Methods: Wild-type and AC10 knockout mice were intratracheally inoculated with increasing doses of P. aeruginosa. Twenty fours after infection, bronchoalveolar lavage fluid (BALF) was collected and the percent of PMNs in the BALF determined. In separate experiments, mice were intratracheally inoculated with P. aeruginosa for 6 or 24 hours and organs (lungs, kidney, liver, spleen and brain) harvested, homogenized and the homogenate cultured overnight on Pseudomonas isolation agar for quantification of colony forming units (CFUs). Results: Our data confirmed CD99 expression in rat pulmonary microvascular endothelial cells and whole lung of both wild type and AC10 knockout mice. While there was no difference in the percentage of PMNs in the BALF between male wild type and knockout animals at any of the bacterial doses tested, in the female AC10 knockout mice, there was a decrease in the percentage of cells PMNs in the BALF compared to female wild type litter mates at several doses tested (1x103 up to 1x105, p<0.05). At a higher dose of P. aeruginosa (2.5x106), there was no difference in bacterial clearance between male WT and AC10 knockout mice, but a trend toward an increase in the CFU harvested from lung tissue 6 hours post infection in female KO mice. Conclusion: Thus, CD99 is expressed in the pulmonary endothelium. Further, in female mice, AC10 plays a role in neutrophil recruitment into the airspace. Further studies are required to resolve whether AC10 plays a role in bacterial clearance in female mice in a model of P. aeruginosa pneumonia. HL121513. This is the full abstract presented at the American Physiology Summit 2024 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.
Comparative Curriculum Analysis for Preclinical Medical Education: Between Cohorts and Between Instructors
Authors: Anderson Lisa , Shaw Aubie , Levine Erica , Nordgren Kendra 
Published: May 2024

Prior to Fall 2023, the two medical campuses of the University of Minnesota, have hadtwo different curricula. Though the Duluth campus has delivered an integrative, systems-based curriculum, the Twin Cities campus has delivered a discipline-basedcurriculum. Outcome measures (1) pass rate and scores on Step 1 board exams, 2)graduation data and 3) match success) demonstrate strong comparability betweenthe two curricula. Starting in September 2020, another opportunity for comparisonoccurred; a single instructor taught pulmonary content to both the Duluth (Fall 2020)and Twin Cities (Spring 2020) cohorts and another single instructor taughtcardiovascular content to both the Duluth (Fall 2020) and Twin Cities (Spring 2021)cohorts. Both cohorts were given and assessed on the same set of learning objectives;leading us to ask the following question: Does the structure of the preclinical curriculum(systems vs discipline-based) impact the learning outcomes of physiology, particularlythe ability to integrate material? We compared the two cohorts by comparing acommon set of exam questions assessing cardiovascular and pulmonary physiology. Wemeasured question performance by question diffculty index (expressed as a percent)and question cognitive level by determining the Bloom’s Taxonomy Cognitive level(knowledge, comprehension, application, analysis, synthesis and evaluation). We foundno differences between the cohorts in question diffculty as a function of content typeor levels of Bloom’s taxonomy. We conclude that there was no difference in overallperformance of the Duluth and Twin Cities cohorts despite receiving different curricularapproaches. However, we had an unexpected finding from the analytics; thecardiovascular items were significantly more diffcult than the pulmonary items. Thisresult has implications for a team-taught medical school curriculum given the source ofthe difference could be the difference in teaching style, the difference in content or thedifference in item writing. We therefore are beginning an exploration of the differencein item analysis and possible impacts on student evaluations. The important of this lineof inquiry is that first, consistency in item diffculty potentially impacts a competencybased medical curriculum and second, how students perceive differences in itemdiffculty has the potential to affects instructor evaluations and therefore promotionand tenure. This is the full abstract presented at the American Physiology Summit 2024 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.
Smooth Muscle-Specific Knockout of LRRC8A Anion Channels Improves Vasodilation in Renal Arteries from Diabetic Mice
Authors: Choi Hyehun , Panja Sourav , Nguyen Hong-Ngan , Webb R. Clinton , Lamb Fred 
Published: May 2024

Leucine Rich Repeat Containing 8 (LRRC8) family proteins (LRRC8A, B, C, D and E) comprise volume-regulated anion channels (VRACs). We previously have shown that knockout (KO) or block of LRRC8A anion channel attenuates reactive oxygen species (ROS) production by Nox1, impairs TNFα-induced inflammation, and increases vascular relaxation in mesenteric arteries. These changes are associated with reduced RhoA activation. Diabetic (db/db−/−) mice have previously been shown to develop vascular dysfunction that is characterized by increased ROS production and enhanced RhoA activation. Diabetic nephropathy causes chronic renal disease and can lead to end-stage renal failure. Oxidative stress plays a role in both the initiation and progression of this process. We hypothesized that LRRC8A KO would protect vascular function in db/db−/− mice and promote vascular relaxation in renal arteries. Smooth-muscle specific LRRC8A KO mice were created in a db/db−/− background. Renal arteries were isolated from db/db−/− WT and db/db−/− LRRC8A KO mice vascular contraction and relaxation were measured. Contractile responses to phenylephrine (PE) were unaltered in LRRC8A KO compared to WT vessels. However, both endothelium-dependent (acetylcholine, ACh) and -independent (sodium nitroprusside, SNP) relaxation were increased in LRRC8A KO compared to WT rings that were contracted with PE (Emax ACh: WT 76.8 ± 5.5 vs. KO 92.2 ± 3.3 %, LogEC50 SNP: WT -7.6 ± 0.14 vs. KO -8.4 ± 0.14, n = 4-5, * p<0.05). These data demonstrate preserved vasodilation in smooth muscle-specific LRRC8A KO blood vessels. This may lead to increased renal blood flow in the setting of db/db−/−-related diabetes. Ongoing work will determine if improved vasodilation is associated with preserved renal function in these animals. If so, VRAC inhibition may provide a novel therapeutic approach to the prevention and treatment of diabetes-induced renal dysfunction. This work was supported by DK132948 and HL160975. This is the full abstract presented at the American Physiology Summit 2024 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.
Unveiling the roles of dietary Tryptophan and Arginine metabolism in Lactobacillus rhamnosus GG-mediated barrier protection
Authors: Antonio Jayson , Suntornsaratoon Panan , Flores Juan , Ambat Jayanth , Bala Ajitha , Jones Abigail , Li Wei Vivian 
Published: May 2024

Inflammatory bowel disease (IBD) is often characterized by increased intestinal paracellular permeability and abnormalities in tight junctions (TJ). IBD patients commonly exhibit reduced serum tryptophan (TRP) levels. Furthermore, animal models on low-TRP diets are more susceptible to chemically induced intestinal inflammation, while those on high-TRP diets show reduced inflammation. The interaction between TRP and gut microbiota in reinforcing the intestinal barrier warrants further investigation. To address this, we introduced Lactobacillus rhamnosus GG (LGG), known for enhancing the gut barrier, and PBS as a control into germ-free mice fed TRP-suffcient or -deficient diets. Our analysis of the mouse ileal transcriptome revealed dramatic upregulation of key genes in arginine metabolism only in LGG-TRP mice, particularly of argininosuccinate lyase ( Asl) that catabolizes argininosuccinate (ASA). Interestingly, our in-silico analysis of human IBD data GEO 179285 transcriptome showed marked dysregulation of similar genes, including inappropriate increases in ASA synthetase ( Ass1). Moreover, this unique expression pattern in the mouse ileum was TRP-dependent and specific to LGG, and not observed in mice monocolonized with pathobiont Ruminococcus gnavus or specific pathogen-free mice. LC-MS analysis of fecal and serum metabolites in LGG-TRP mice revealed elevated levels of fecal arginine, glutamine, and aspartate, suggesting their involvement in host arginine biosynthesis, along with significant reductions in serum ASA levels. ASA was highly negatively correlated with numerous TJ genes, suggesting its potential to compromise barrier function. Indeed, treating mouse enteroids with ASA enhanced dextran permeability, exacerbated LPS disruption of the gut barrier, and decreased expression of TJ genes Ocln and Tjp1. Furthermore, elevated serum ASA and decreased colonic ASL levels were observed in colitis-afflicted mice, perturbing gut homeostasis, as indicated by increased fecal lipocalin-2 and delayed colitis recovery after intraperitoneal ASA administration. We propose that LGG-TRP stimulates gut-mediated ASA turnover as evidenced by substantial increases in Asl levels. Interestingly, LGG alone reduced ASA concentration in the culture medium under anaerobic and aerobic conditions. Collectively, our study identifies ASA as a potential biomarker of gut inflammation and enhanced permeability. Moreover, we highlight the potential of LGG-TRP therapy for IBD-associated leaky gut conditions, offering novel insights for gut health interventions. NIHR01-AT010243 (NG,RF), R01DK119198 (NG), NSF 1754783 (RF). This is the full abstract presented at the American Physiology Summit 2024 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.
Exercise Training Mitigates Inhibition of Skeletal Muscle Mitochondrial Respiration with Empagliflozin Treatment in Male and Female Mice
Authors: Murphy Michael , McGowan Erin , Batterson Philip , Brim-Edwards Jackson , Newsom Sean , Robinson Matthew 
Published: May 2024

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are antihyperglycemic drugs designed to lower renal glucose reabsorption, yet recent evidence indicates that SGLT2i have off-target effects on skeletal muscle to inhibit mitochondrial respiration. Such inhibition raises important questions regarding the interaction of SGLT2i and exercise on regulation of skeletal muscle mitochondrial metabolism. The purpose of the current study was to test the hypothesis that SGLT2i treatment (empagliflozin, EMPA) would blunt improvements to skeletal muscle mitochondrial oxidation capacity following aerobic training. Male and female C57BL/6J mice consumed a western diet (40% kcal from fat) for 8 weeks, then performed an additional 8 weeks of either treadmill training (5 times per week progressing up to 23 m/min) or remained sedentary. During the intervention period, all mice consumed either western diet or western diet enriched with EMPA (10mg/kg diet) in a 2x2 design (n=10/group for each sex). We isolated mitochondria from quadriceps muscles collected 72 hours after the final training session (or rest) and measured ex vivo mitochondrial substrate oxidation capacity using high-resolution respirometry. There was an interaction between exercise and EMPA (p=0.037) on complex I-II respiration whereby sedentary mice had lower respiration following EMPA versus untreated (-17% p=0.01) while exercise-trained mice had similar respiration between EMPA and untreated. The interaction was less prominent in complex I-supported respiration (p=0.06) or complex-II alone (p=0.09). Our results show that, contrary to expectations, EMPA treatment did not impair mitochondrial adaptations to exercise training. Instead, exercise training prevented the suppression of mitochondrial respiration during EMPA treatment. These findings indicate that aerobic exercise has positive effects on the off-target inhibition of mitochondrial respiration by SGLT2i. Supported by funding from the Collins Medical Trust (Wilsonville, Oregon) awarded to Matthew Robinson. This is the full abstract presented at the American Physiology Summit 2024 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 disturbances on heart rate of captive loggerhead turtles
Authors: Williams Cassondra , Sato Katsufumi , Ponganis Paul 
Published: May 2024

Diving animals are subject to disturbances within their underwater habitat, such as interactions with fisheries, vessel traffc and increased noise in the ocean. Research on the effect of disturbances on marine mammals and birds suggest stress related to disturbances can result in either increased or decreased heart rates. However, how disturbances affect endangered or threatened marine turtles is largely unknown. Relying on behavioral data is insuffcient because animals may respond physiologically to a stressful event but demonstrate no change in behavior. To assess how marine turtles respond to disturbances, we examined the heart rate of subadult loggerhead turtles (43.5 ± 9.1 kg) that were incidentally captured by set nets in or near Otsuchi Bay, Japan. Heart rate was measured in turtles at rest in shallow tanks (n=4), resting out of water (n=4), actively feeding (n=4) and during transport in a car (n =3) using self-contained ECG data loggers. Heart rate during car transport was significantly higher than all other categories (F = 80.9, p< 0.001). Mean heart rate during transport was at least 15 beats min−1 higher than any other category, even though turtles were typically calm during transport. The mean time for heart rate to recover to resting in water heart rate was 58 minutes; however, heart rate recovery varied widely and was likely dependent on post-transport activity. While previous research showed heart rate during routine activities in loggerhead turtles was driven by activity level, these results suggest that, during stressful events, heart rate can increase dramatically even though behaviorally, turtles appear quiescent. National Science Foundation, IOS-1121324. This is the full abstract presented at the American Physiology Summit 2024 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.