bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance-Exercise-Induced Circulating Factors on Damaged Skeletal Muscle Tissue Proteome in Young Untrained Men
Authors: Jiwan Nigel , Levitt Danielle , Appell Casey , Luk Hui-Ying
Published: May 2024

Recovery from muscle damage is tightly orchestrated by multiple physiological processes that can be altered by circulating factors (e.g., cytokines, growth factors) and intracellular signaling pathways (e.g., autophagy). Our previous studies have demonstrated that resistance exercise (RE)-induced circulating factors alter the expression of intramuscular cytokine mRNA and autophagic and myogenic markers in exercise-induced skeletal muscle damage (EIMD). However, the global effects of these circulating factors on damaged muscle are largely understudied. Purpose: To identify global changes in the proteome and functional pathways in skeletal muscle when EIMD is followed by an upper body RE-induced circulating milieu. Hypothesis: RE-induced circulating factors alter protein expression profile in damaged muscle. Methods: Vastus lateralis samples from 3 men included in the parent study were utilized for this report. Untrained men (age: 23 ± 5yr; height: 181.6 ± 5.9cm; weight: 86.0 ± 15.8kg) completed 2 identical bouts of maximal unilateral eccentric knee extensions for 8 sets of 10 repetitions, which were immediately followed by either heavy upper body RE to induce changes in circulating factors (EX) or 20 min seated rest (CON). Muscle samples from the damaged leg at 24h were used to compare between conditions. The total number of proteins was measured using LC-MS/MS. Bioinformatic analyses were performed via Qiagen Ingenuity Pathway Analysis software. For identifying enriched biological processes and functions, proteins had to have at least 1.0-fold differential expression with an FDR-adjusted significance level < 0.05. Z scores were calculated to predict changes in biological functions. Results: A total of 900 proteins were identified. For EX, 79 proteins were downregulated, and 15 were upregulated compared to CON at 24h. Pathway analyses demonstrated that for EX, there was decreased activation in acute phase response signaling, liver X receptor/retinoid X receptor activation, nitric oxide production and reactive oxygen species in macrophages, and neutrophil extracellular trap signaling pathways compared to CON. In addition, for EX, there was an increase in macrophage IL-12 signaling and production than CON. Conclusion: RE-induced changes in circulating factors modulated pathways associated with the immune response and cytokine signaling in untrained men. Given that immune response is critical for recovery from muscle damage, these results highlight the potential role of RE-induced circulating factors (e.g., hormones, growth factors, etc.) which could play a role in mediating muscle recovery.

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.
Adropin Treatment Restores Cardiac Function and Metabolic Flexibility in Diabetic Cardiomyopathy
Authors: Mushala Bellina , Stoner Michael , McMahon Brenda , Vandevender Amber , Mullett Steven , Gelhaus Stacy , Jurczak Michael
Published: May 2024

Background: Diabetic cardiomyopathy (DCM) is a major complication of diabetes, and has been recognized as a cause of heart failure independent of other common risk factors. Metabolic inflexibility is a hallmark feature, where increased free fatty acid availability and decreased myocardial glucose uptake lead to an over-reliance on fatty acid oxidation, reducing cardiac work effciency. Energetic ineffciency in diabetic hearts may have profound implications for cardiac function under conditions of increased workload, and therefore therapeutic approaches are warranted. Adropin is a liver- and brain-secreted peptide hormone shown to regulate fuel metabolism in the heart. Adropin levels are significantly reduced in obese and diabetic human subjects, and this decrease is linked to increased adiposity, insulin resistance, and impaired glucose tolerance. Our lab recently showed that acute adropin treatment restores glucose oxidation activity in the hearts of prediabetic obese mice. However, the effects of chronic adropin exposure in the heart remains unknown. Hypothesis: We hypothesize that adropin treatment will exhibit beneficial effects on cardiac fuel metabolism that may lead to long-term improvements in functional output. Methods: We used a preclinical model of DCM to investigate the effects of long-term adropin treatment on cardiac structural and metabolic remodeling. Mice were treated with adropin daily for four weeks, and subjected to echocardiography, glucose tolerance tests, histopathology, RNA-sequencing, and metabolomics. Results: We report that long-term adropin treatment restores normal cardiac structure and metabolic function in the diabetic heart, by inhibiting flux of non-oxidative glycolytic intermediates into the hexosamine biosynthetic pathway. Conclusions: Our findings highlight the therapeutic potential of adropin signaling to attenuate cardiac remodeling in DCM.

The project described was supported by NIDDK 1F31DK134089 and NHLBI R01HL147861.

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.
Impact of Non-alcoholic Fatty Liver Disease on development of diabetes complications
Authors: Burkhanova Maftunakhon , Shamansurova Zulaykho , Rakhmonova Gulzor , Rustamov Sardor , Maksutova Nigora , Aykhodjaeva Mokhira
Published: May 2024

Introduction. Non-alcoholic Fatty Liver Disease (NAFLD) shown frequent future in patients with type 2 Diabetes Mellitus (DM2). By affecting insulin metabolism, glucose production and gluconeogenesis liver disorders probably involved into DM2 clinical future and development of complications. We studied the role of the NAFLD in the development of diabetic complications such as retinopathy (DR), neuropathy (DPNP), nephropathy (DN). Material and methods. 62 patients with DM2 who were admitted into Republican Specialised Scientific Practical Medical Centre of Endocrinology named after acad. Y.Kh. Turakulov were observed. In all patient blood glucose, HbA1c, total blood count, urine test, blood lipids, AlT, AsT, alkaline and acid phosphatase, … were measured. Liver, pancreas, gall bladder were visualised by ultrasound. Results. Among patients with DM NAFLD were detected in 45% of patients with DM2. Patients average age, BMI, HbA1c, blood fibrinogen level were greater in NAFLD group, whereas there were no found any differences between ALT, AST, BUN, creatinine levels. Blood total platelets were decreased in NAFLD group (10.6%, p<0,05). Fib4 score was higher in NAFLD group by 1.5 times, where comparison of Fib4 score according to DN stages shown 2.57 times higher score in patients with DN4 and DN5. Patients with NAFLD diabetes complications were higher, especially DR by 1.2 times, DPNP 1.3 times and DN by 1.5 times than without NAFLD. Moreover, number of patients with NAFLD treated by insulin were 2 times more than without NAFLD. Conclusion. NAFLD is a frequent future among patients with DM2, have linkage with patients’ age, BMI, HbA1c level, depend from severity of DR, DPNP and DN. Blood platelets were lower in NAFLD group, where Fib4 score was 1.5 times higher. Results suggested about involving of NAFLD into diabetic complication development.

NA.

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 nitric oxide bioavailability promotes arterial stiffening in a tissue transglutaminase-dependent manner
Authors: Ramirez-Perez Francisco I. , Lateef Olubodun M. , Foote Christopher A. , Manrique-Acevedo Camila , Martinez-Lemus Luis A. , Padilla Jaume
Published: May 2024

Although arterial stiffening undeniably contributes to cardiovascular disease, the cellular and molecular mechanisms leading to increased arterial stiffness are not well understood. Increased arterial stiffness in disease states such as obesity and type 2 diabetes typically coexists with indices of endothelial dysfunction including diminished nitric oxide (NO) bioavailability. In fact, it is commonly assumed that endothelial dysfunction precedes, and causally contributes to, arterial stiffening; yet the molecular underpinnings for this causal relationship remain elusive. We and others previously showed that activation of tissue transglutaminase (TG2), a crosslinking enzyme that also works as a G-protein and cellular scaffold, promotes cytoskeletal actin polymerization and stiffening of vascular smooth muscle cells (VSMC), thus contributing to whole-artery stiffening. It is also reported that NO is an endogenous inhibitor of TG2. Accordingly, herein, we tested the hypothesis that increased exposure of VSMC to NO suppresses TG2 activity and actin polymerization. Conversely, we hypothesized that loss of NO bioavailability promotes arterial stiffening, and that this effect is mediated by TG2 activity and downstream activation of LIM kinase (LIMK), an enzyme that modulates fibrillar (F)-actin severing via cofilin phosphorylation. All differences reported herein are significant at P<0.05. In support of our hypotheses, we show that treatment of cultured human aortic VSMC with the NO donor S-nitrosoglutathione (200μM for 2 hours) reduces TG2 activity (N-epsilon gamma glutamyl Lysine presence) and F-actin formation (phalloidin staining) induced by TG2 activation (dithiothreitol, 200μM). Furthermore, we show that exposure of mouse isolated mesenteric arteries to the NO synthase inhibitor L-NAME (300μM for 18 hours) causes an increase in arterial stiffness ( i.e., increased incremental modulus of elasticity) as determined using pressure myography and videomicroscopy. Of note, L-NAME-induced arterial stiffening is prevented when arteries are co-treated with a TG2 inhibitor (cystamine, 1mM) or LIMK inhibitor (LIMKi, 1μM). Taken together, these findings support the notion that NO is a key downregulator of TG2 activity and demonstrate that reduced NO bioavailability promotes arterial stiffening in a VSMC TG2-LIMK-F-actin dependent manner. As such, this work provides insight into plausible molecular mechanisms by which endothelial dysfunction leads to arterial stiffening.

R01HL153264 (to LAML and JP), and MU Research Excellence Program (REP) postdoctoral fellowship (to FIRP).

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.
Automating Polysomnography in an Under-Explored Animal Model: Preliminary Results from Hibernating Bears
Authors: Tøien Øivind , Pittaras Elsa Cecile , Huang Yi-Ge , Brodersen Paul , Allocca Giancarlo , Barnes Brian M. , Heller H. Craig
Published: May 2024

Animal hibernation is a hypometabolic state that may inform translational research to improve clinical outcomes for hypoxic patients whose oxygen supply does not match their demand. Bears are an excellent animal model, as they decrease their body temperature to only 30-35°C during hibernation and suppress their metabolism down to 25% of normal resting levels while having a more comparable physiology to humans than deep hibernators such as small rodents. As little is known about their sleep patterns during hibernation, we continuously monitored for more than 3500 days via biotelemetry a variety of physiological parameters from 16 captive American black bears in and out of hibernation. We recorded EEG, EOG and EMG signals that are commonly used to determine wake, REM sleep and NREM sleep vigilance states in conventional animal models (polysomnography). Such a data set is too large to fully annotate manually, so we compared two automated approaches. We first manually annotated two one-day recordings at body temperature extremes from each of 6 bears during hibernation when body temperatures were oscillating widely in multiday cycles with intermittent bouts of shivering (Tøien et al. 2011). We also manually scored a one-day, non-hibernating recording at normal (summer) body temperature from these bears. Based on this reference data set, we evaluated two automated scoring applications based on different machine learning classifiers: open source Somnotate (author Paul Brodersen), which is trained on multiple files, and proprietary Somnivore (author Giancarlo Allocca), which is trained on a subset of epochs from each individual recording. Somnotate gave best results during hold-one-out testing when using separate models for hibernating and non-hibernating data, and then performed comparably for both conditions. Somnivore was by design trained on a small subset (100 epochs of each kind) of each file to be tested. Both applications provided typical F-measures against manual reference scores in the 0.90-0.97 range. Outliers in the lower 0.72-0.88 range were highly correlated between the two applications, indicating that specific files are more challenging to annotate — either manually, automatically, or both. We conclude that both applications have accuracies on par with manual scorers when trained on high quality data.

Supported by NIH COBRE under grant number [P20GM130443].

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.
Molecular Basis of Different Flow-Induced Responses of Small Intra- and Extracranial Cerebral Arteries: Role of Arachidonic Acid and Nitric Oxide Pathways
Authors: Koller Akos , Nemeth Zoltan
Published: May 2024

Background / Objectives. Previous studies showed that increases in intraluminal flow elicit primarily dilations in isolated rat extracranial basilar arteries (BA), whereas constrictions in the intracranial middle cerebral arteries (MCA) (Koller A, Toth P. J Vasc. Res. 2012, PMID: 22739136). These responses are most likely due to the absence or presence of physical constraints (rigid cranium). Thus, we hypothesized that the underlying molecular pathways are also different, corresponding to the functional vasomotor responses. Material and Methods. Protein and gene expression of key AA-pathway enzymes and receptors, such as cyclooxygenase (COX1 and COX2) and thromboxane A2 receptor (TxA2R), and vasodilator enzymes, such as prostacyclin synthase (PGIS) were measured in isolated BA and MCA from male rats (3 months old, n=18). Results. By western blotting protein expression of vasoconstrictor metabolites COX1/2, Cyp4A and receptor TBXA2R were significantly higher whereas expression of dilator PGIS was significantly lower in MCA than in BA. Using qPCR we found that expression of genes coding vasoconstrictor enzymes COX1/2, Cyp4A and receptor TBXA2R was significantly higher, whereas gene coding dilator PGIS was significantly lower in intracranial compared to extracranial arteries. In addition, RNAseq analysis demonstrated that expression of multiple genes coding vasoconstrictor molecules is higher in intracranial compared to extracranial arteries. Conclusions. These findings provide mechanistic basis for the observed different functional, vasomotor responses of BA and MCA to increases in flow, by showing the different expression of enzymes (COX1/2, Cyp) producing constrictor prostanoids (such as 20-HETE), receptors (TxA2R) and dilator prostanoid (PGIS). In addition, these findings reinforce the importance of regional differences in the regulation of cerebral arterial resistance, thereby providing appropriate blood flow to the brain, and at the same time, autoregulation of cerebral blood flow.

Ministry of Innovation and Technology (MIT) of Hungary-NRDI TKP2020-NKA-17, TKP2021-EGA-37, and National Research, Development, and Innovation Offce (NKFIH) OTKA K 132596 K_19, and Hungarian Academy of Sciences, Post-Covid 2021-34, and HUN-REN-SU: 02068 of Hungary.

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.
ASK1-mediated Apoptosis in Human Lung Fibroblasts
Authors: Huffman Emily , Gordon Elizabeth , Dong Brittany , Camus Sarah , Freeberg Margaret , Thatcher Thomas , Sime Patricia
Published: May 2024

Idiopathic pulmonary fibrosis (IPF) is a chronic, devastating lung disease characterized by progressive fibrosis and dysregulated wound repair that negatively affect lung function. Although lung fibroblasts are important in repair mechanisms following lung injury, differentiation into myofibroblasts in the presence of TGF-β and resistance to apoptosis can promote the progression of pulmonary fibrosis. Apoptosis signal regulating kinase 1 (ASK1) is a member of the mitogen activated protein (MAP) kinase family that is known to promote apoptosis. The objective of this study was to test the hypothesis that ASK1 is an important mediator of apoptosis in lung fibroblasts. Normal human lung fibroblasts were obtained from five donors and cultured in the presence or absence of TGF-β (1ng/mL) for 72h. Apoptosis was assessed by a Caspase-Glo® 3/7 assay following treatment with a combination of cycloheximide and Fas ligand antibody with or without the ASK1 inhibitor, selonsertib. Expression of α-smooth muscle actin (α-SMA), collagen, ASK1, and survivin (a member of the inhibitor of apoptosis protein family) were determined by western blot. Apoptosis was induced in three of the five donor lines, and selonsertib treatment reduced caspase-3/7 activity. These donor lines expressed lower levels of survivin compared with the non-responding lines. TGF-β did not significantly affect these results. As expected, TGF-β stimulated expression of collagen and α-SMA in all donor lines, but this was reduced by treatment with selonsertib. Interestingly, TGF-β caused a reduction in the expression of ASK1 which is consistent with the idea that myofibroblasts in IPF are resistant to apoptosis. These results suggest that ASK1 can promote apoptosis in normal lung fibroblasts, but this is dependent upon the expression of survivin.

Supported by VA Merit Award BX005889 (CMW) and NIH grant HL131526 (CMW).

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.
Selective KCNQ2/3 Potassium Channel Opener ICA069673 Inhibits Excitability in Mouse Vagal Sensory Neurons
Authors: Sun Hui , Meeker Sonya , Undem Bradley
Published: May 2024

The excitability of vagal sensory neurons is abnormally enhanced in inflammatory visceral diseases, contributing to the unproductive and diffcult-to-treat neuronally based symptoms such as non-cardiac chest pain and excessive coughing. Identification of targets and modulators capable of regulating the excitability of vagal sensory neurons may lead to novel therapeutic options. The KCNQ/KV7/M-channel is increasingly recognized as an intrinsic regulator of excitability in neurons, and several neuronal KCNQ2/3-selective M-channel openers have been developed. This study aimed to characterize the effects of one of these KCNQ2/3-selective activators, ICA-069673, on the M-current (IM) in mouse nodose neurons, and to determine its effects on excitability and action potential firings using perforated patch-clamp technique. The results showed that ICA-069673 enhanced IM density, accelerated the activation and delayed the deactivation of M-channels in a concentration-dependent manner. The EC50 of ICA-069673 in enhancing IM determined at -30 mV is 0.52 μM. ICA-069673 at 10 μM shifted the voltage-dependent activation of IM in hyperpolarizing direction by -25.5 ± 4.1 mV (p<0.001) and increased the maximal conductance from 8.1 ± 4.0 to 12.6±7.4 nS/pF (p=0.031). In a total of 48 nodose neurons studied on voltage-clamp mode, ICA-069673 enhanced IM in 41 neurons (~85%). Consistent with its effects on IM, ICA-069673 induced a marked hyperpolarization of resting potential and reduced the input resistance. The hyperpolarizing effect was more pronounced in partially depolarized neurons. Moreover, ICA-069673 caused a 3-fold increase in the minimal amount of depolarizing current needed to evoke an action potential, and significantly limited the action potential firings in response to sustained suprathreshold stimulations. These results indicate that opening KCNQ2/3-mediated M-channels is suffcient to suppress the excitability and enhance spike accommodation in vagal sensory neurons, and provide evidence supporting further investigation into the effcacy of ICA-069673 in normalizing the aberrant vagal visceral nociception.

The study is supported by NIH Grant R35HL155671.

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.
Peripheral Blood Mononuclear Cells from Patients with Systemic Lupus Erythematosus Induce Salt Sensitivity of Blood Pressure in Humanized Mice
Authors: Saleem Mohammad , Ahmad Taseer , Haynes Alexandria Porcia , Major Amy , Ormseth Michelle , Stein Michael , Kirabo Annet
Published: May 2024

Salt sensitivity of blood pressure (SSBP) is an independent risk factor for cardiovascular disease (CVD), even in normotensive people. Systemic lupus erythematosus (SLE) is also a risk factor for CVD and hypertension. SLE and CVD are on the rise, and it is not known if this is attributable to the increased dietary salt in the modern diet and SSBP. Isolevuglandins (IsoLGs) adduct self-proteins forming neoantigens in antigen presenting cells (APC) to activate T cells and produce cytokines that promote sodium retention, kidney damage, salt sensitivity of blood pressure, and SLE. We hypothesized that high salt intake increases both blood pressure and the proinflammatory milieu in mice humanized with the immune cells of patients with SLE. We humanized female NSG/MHCI/MHCII−/− immunodeficient mice with peripheral blood mononuclear cells (PBMCs) isolated from patients with SLE (n=5) and controls without autoimmune disease (n=4). The blood pressure was measured with radiotelemetry, immune phenotyping was performed with flow cytometry, and vascular reactivity was assessed in mesenteric arteries using wire myography after two weeks of a 4% high salt diet. High salt treatment significantly increased systolic blood pressure in lupus mice compared to the controls (135.5 vs. 123.8 mmHg, p=0.014). APC infiltration (macrophages, monocytes, dendritic cells), their activation (CD86) and proinflammatory markers (IL-23 p19, TNF-alpha), and oxidative stress (Isolevuglandins, Nox2) were significantly higher in the kidneys of lupus mice. Moreover, the signaling molecule p-STAT3 was significantly higher in myeloid cells in the kidneys of lupus mice. The classical monocyte and proinflammatory markers were significantly elevated in the spleen lymphocytes, and proinflammatory markers were increased in the kidney, spleen, and aorta in lupus mice. These mice exhibited vascular dysfunction (p<0.05), suggesting reduced vascular compliance. We measured urine albumin and found that lupus mice tended to excrete more albumin than the controls (17.24 vs. 25.89 μg/ml p=0.142), suggesting greater kidney injury. In conclusion, our findings suggest that immune cells from patients with SLE, in response to high salt intake, increase blood pressure and the proinflammatory milieu in the kidney, aorta, and spleen; impair vascular compliance; and worsen albuminuria in immunodeficient mice.

1R01HL144941-01A1 1R03HL155041 23CDA1053072.

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.
Reorganization of Actin Cytoskeleton and Reduction of Cortical Elasticity in Podocytes Lacking Acid Ceramidase: Role of Sphingomyelinase-Like Phosphodiesterase 3b
Authors: Li Guangbi , Huang Dandan , Ren Jenna , Zou Yao , Kidd Jason , Gehr Todd , Li Pin-Lan
Published: May 2024

Podocytopathy and associated nephrotic syndrome have been reported in a mouse strain (Asah1fl/fl/Podocre) with a podocyte-specific deletion of α subunit (the main catalytic subunit) of acid ceramidase (AC). Nevertheless, the pathogenic mechanism of podocytopathy in these mice remains poorly understood. Given that sphingomyelinase-like phosphodiesterase 3b (SMPDL3b) has been recently reported to play a vital role in maintaining the actin cytoskeleton and normal function of podocytes, the present study tested whether Asah1 gene deletion-induced podocytopathy is attributed to altered SMPDL3b activity and reorganized actin cytoskeleton in podocytes. By Western blot analysis and SMPDL3b enzyme activity assay, we demonstrated that Asah1 gene knockout remarkably decreased both expression and function of SMPDL3b in podocytes isolated from Asah1fl/fl/Podocre mice compared to podocytes of wild type (WT/WT) mice. As a monoclonal antibody which can bind to and stabilize SMPDL3b on podocytes, rituximab was found to significantly recover SMPDL3b expression and activity in podocytes lacking Asah1 gene. Correspondingly, Asah1 gene deletion reduced podocin expression in podocytes, which was attenuated by rituximab treatment. Phalloidin staining of F-actin showed elevation of cortical actin and reduction of stress fiber in podocytes lacking Asah1 gene. Such actin cytoskeleton redistribution was significantly attenuated by rituximab. Moreover, atom force microscopy was used to study the impact of actin cytoskeleton remodeling on mechanical properties of podocytes. Asah1 gene knockout was found to increase podocyte height but decrease cortical elasticity in these cells. These pathological changes were significantly inhibited by rituximab, suggesting the restoration of actin cytoskeleton in podocytes lacking Asah1 gene by rituximab. In vivo, intraperitoneal injection of rituximab markedly attenuated proteinuria and albuminuria in Asah1fl/fl/Podocre mice compared to control groups. In summary, our findings suggest that alteration of SMPDL3b activity and reorganization of actin cytoskeleton in podocytes may contribute to the pathogenesis of podocytopathy in mice with podocyte-specific Asah1 gene deletion.

This study was supported by NIH grants DK054927 and DK120491.

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.
Contribution of Gasdermin D Pore Formation to NLRP3 Inflammasome Product Secretion and Pyroptosis in Podocytes during Obesity-Induced Glomerulopathy
Authors: Huang Dandan , Ren Jenna , Zou Yao , Kidd Jason , Gehr Todd , Li Pin-Lan , Li Guangbi
Published: May 2024

NLRP3 inflammasome activation in podocytes has been reported to play an important role in the development of glomerular inflammation and sclerosis during obesity. Although, the molecular mechanism mediating the secretion of NLRP3 inflammasome products to induce local inflammatory response remains poorly understood. Given that gasdermin D (GSDMD) has been found to form oligomeric pores on plasma membrane for release of inflammasome product and execution of pyroptosis, the present study tested whether GSDMD pore contributes to NLRP3 inflammasome product secretion and pyroptosis in podocytes and thereby initiates glomerular inflammation and sclerosis in obesity-induced glomerulopathy (ORG). By Western blot analysis, we demonstrated that palmitic acid (PA) as an obesity-related danger factor dose-dependently stimulated the reduction of total GSDMD and elevation of cleaved GSDMD (GSDMD-NT) in podocytes. In vivo, glomerular decrease in total GSDMD and increase in GSDMD-NT were remarkable in wild type (WT/WT) mice on high-fat diet (HFD) compared to control mice. Urinary excretion of NLRP3 inflammasome products was also significantly increased by HFD treatment. Moreover, we found that pre-treatment with amitriptyline or MCC950 blocked NLRP3 inflammasome activation as well as GSDMD pore formation on plasma membrane of podocytes, while disulfiram prevented GSDMD pore formation without affecting NLRP3 inflammasome activation. Since acid sphingomyelinase (ASM)-ceramide signaling pathway plays a vital role in the development of ORG, we examined whether ASM activity determines GSDMD pore formation in podocytes. By atom force microscopy, a 3D topography map of a single podocyte was generated, and pore-like structures were observed in the membrane of PA-treated WT/WT podocytes. Podocytes lacking Smpd1 (gene code of ASM) gene did not show pore formation, but Smpd1 gene overexpression amplified PA-induced pore formation in podocytes. Moreover, it was found that HFD-induced GSDMD cleavage and pyroptosis in glomeruli were blocked by Smpd1 gene deletion in Smpd1−/− mice. On the contrary, podocyte-specific Smpd1 gene overexpression amplified GSDMD-NT production and pyroptosis in glomeruli. Correspondingly, HFD-induced podocyte foot process effacement and glomerular sclerosis in mice were inhibited by Smpd1 gene knockout but exaggerated by podocyte-specific Smpd1 gene overexpression. Taken together, our findings suggest that ASM-ceramide signaling pathway may control GSDMD pore formation in podocytes to determine glomerular inflammation and sclerosis in ORG.

This study was supported by NIH grants DK054927 and DK120491.

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.
Cardiac autonomic function in young healthy Hispanic/Latino adults
Authors: Dalve Ashlesha , Perez Justo , Nyarko Ruby , Fatahimeiabadi Zahra , Dombroski Lindsay , Kaur Jasdeep
Published: May 2024

The Hispanic/Latino (H/La) population in the US experiences a notably high incidence of hypertension. Recent epidemiological findings reveal that more than 50% of H/La men over the age of 20 years suffer from high blood pressure. Even among adolescents aged 8 to 17 years, H/La youth exhibit the highest prevalence of hypertension compared to other racial groups. This significantly elevates the risk of cardiovascular diseases across the lifespan of this population. H/La is the largest ethnic minority in the US, constituting 19.1% of the current population, and is projected to make up 1/3rd of the US population by 2050. As such, it is crucial to study the potential mechanism responsible for the health disparities in this population. In this study, we investigated the cardiac autonomic function by assessing the baroreflex sensitivity (BRS) and heart rate variability (HRV) in young, healthy H/La and non-Hispanic white (NHW) individuals. We hypothesized that the cardiac autonomic function (BRS and HRV) will be impaired in young healthy H/La as compared to the healthy NHW adults. Ten minutes of resting beat-to-beat blood pressure (BP; finger plethysmography) and heart rate (ECG) were measured in 14 young healthy H/La adults (11 men, 3 women) and 14 age-, sex- and weight-matched NHW adults [age (H/La: 20 ± 2yr; NHW: 22 ± 4yr; mean ± SD, p=0.32); BMI (H/La: 24 ± 2 kg/m2; NHW: 24 ± 2 kg/m2; p = 0.92); positive family history of hypertension (H/La: 21.4%; NHW: 21.4%). The resting heart rate (H/La = 59 ± 5 bpm; NHW = 55 ± 6 bpm; p = 0.12), systolic BP (H/La = 107 ± 6 mmHg; NHW = 111 ± 6 mmHg; p = 0.14) and diastolic BP (H/La = 61 ± 5 mmHg; NHW = 63 ± 6 mmHg; p = 0.46) were similar in both the groups. The respiratory rate (H/La = 14 ± 3 bpm; NHW = 14 ± 3 bpm; p = 0.41) and the sample data used (H/La = 591 ± 59 beats; NHW = 554 ± 63 beats; p = 0.12) for both the populations were similar. We found that BRS (overall gain; H/La = 24 ± 6 ms/mmHg; NHW = 27 ± 10 ms/mmHg; p = 0.39) and heart rate variability (root mean square of successive differences between normal heart beats; RMSSD, H/La = 82 ± 29 ms; NHW = 102 ± 48 ms; p = 0.101) were not significantly different between the two groups. These data suggest that baroreflex sensitivity and heart rate variability are not different between young, healthy H/La and NHW adults.

Supported by Kinesiology and Health Education UT Austin Start-up Account 19-2635-91.

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.
Engineering of Genetically Encoded Calcium Channel Blockers
Authors: Liu Xiaoxuan , Zhou Yubin
Published: May 2024

Calcium Release-Activated Calcium (CRAC) channel is a highly Ca2+-selective store-operated channel constituted by two-component mediators (STIM and ORAI) and controls a wide range of cellular functions in various tissues. Gain-of-function (GoF) mutations of CRAC channel cause excessive Ca2+ entry, which can lead to serious diseases such as tubular aggregate myopathy and Stormorken syndrome (TAM/STRMK). To solve this problem and to gain precise control of the CRAC channel, we have designed both an optogenetic and a chemogenetic strategy for engineering of CRAC channel blockers (designated Opto-CRAB and Chemo-CRAB), which can mediate Ca2+ influx and Ca2+-dependent signaling such as NFAT induced gene expression and T cell activation. Beyond in vitro applications, both Opto-CRAB and Chemo-CRAB have been applied in vivo experiments in a zebrafish model of Stormorken syndrome that resulted in the mitigation of thrombocytopenia and hemorrhage in light and chemical dependent manners.

Welch Foundation (BE-1913-20220331 to Y.Z.), Leukemia & Lymphoma Society (LLS6680-24 to Y.Z.), the National Institutes of Health (R01GM144986 to Y.Z. and R21AI174606 to Y.Z.).

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.
A New Cell Type in Pulmonary Veins
Authors: Tang Yashu , Chen Yen-Lin , Bazaz Abhishek , Delancey Rachel , Daneva Zdravka , Sonkusare Swapnil K.
Published: May 2024

Pulmonary veins (PVs) carry oxygenated blood from lungs back to the heart and may play an important role in preventing blood backflow from the left atrium. Previous studies show that large PVs exhibit spontaneously pulsatile contractions in cardiomyocyte-like manner. However, the contractions of small PVs have not been investigated. We hypothesized that Ca2+ signaling mechanisms in the myocytes mediate small PV contractions. Small, 4th-order PVs from C57BL6 mice were obtained and imaged. Pressurized PVs showed ryanodine receptor-dependent Ca2+ signals and spontaneous contractions. Light sheet fluorescence microscopy and immunostaining showed the expression of troponin C, a cardiomyocyte marker, in the myocyte layer of small PVs, which was not observed in the pulmonary arteries, vena cava, or mesenteric veins. Based on these results, we termed these cells cardiomyocyte-like (CML) cells. In the study of mice with Myh11 Cre-driven tdTomato expression, Myh11 expression was observed in CML cells in small PVs, which was not seen in the smooth muscle cells (SMC) of small PAs. Endothelial protrusions crossing the connective tissue layer into the CML layer were also observed in PVs. Previous studies showed PV remodeling in pulmonary hypertension (PH), and impaired Ca2+ signaling in PAs contribute to higher pulmonary arterial pressure in PH. We further hypothesized that ryanodine receptor (RyR) Ca2+ signals in CML cells are impaired in PH. Results show that RyR Ca2+ signaling was reduced in CML cells of PH mice (injected with Su5416, subjected to chronic hypoxic conditions). Overall, our findings identify a new cell type in small PVs. Moreover, our data show that RyR Ca2+ signals in CML cells underlie spontaneous contractions in small PV, and are impaired in PH. We propose that RyR signaling mechanisms in CML cells may be possible targets for therapy in pulmonary vascular disorders.

This work was supported by funding from the National Institute of Health to Swapnil Sonkusare (R01:HL146914, R01:HL157407).

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.
Chronic, episodic nicotine exposure enhances the hypoxic ventilatory response in adult female rats
Authors: Wollman Lila , Fale Megan , Fregosi Ralph
Published: May 2024

It is well known that cigarette smoking causes lung disease and damages the airways. However, we know little about the direct role of nicotine, the primary addictive component of tobacco, in the development of smoking- related diseases. Along with promoting cancer cell proliferation and airway inflammation, nicotine can modulate central respiratory control, increasing the rate and depth of breathing through mechanisms that are not well understood. In addition, cigarette smoking is associated with obstructive sleep apnea, a sleep-related breathing disorder that is marked by reduced brainstem respiratory motor output. Despite these examples indicating that chronic nicotine exposure in adulthood may alter central respiratory control, there is no published research that directly tests this hypothesis. We exposed male and female adult rats to nicotine for four weeks through their drinking water and then used whole body plethysmography to test the hypothesis that chronic, episodic nicotine exposure alters restful breathing and the hypoxic ventilatory response (HVR), a critical respiratory chemoreflex. We measured tidal volume (TV) and frequency of breathing at rest, and during a 5- minute episode of hypoxia (10% oxygen/balance nitrogen). Total ventilation (VE/VCO2) was calculated as TV X Frequency and normalized to carbon dioxide production, to account for changes in metabolism, and body weight. For both males and females, comparisons were made between groups and across trials using a 2-way ANOVA and Tukey’s post-hoc test. In male rats, nicotine exposure significantly decreased overall ventilation at rest in one of three trials (Trial 1 VE/VCO2: Nicotine exposed, 30.7±7.5 mL/min/100g, Control, 44.3±6.4 mL/min/100g, p=0.0183), but had no effect on breathing during hypoxia. In female rats, nicotine exposure had no effect on breathing at rest, however, overall ventilation during hypoxia was enhanced in nicotine exposed rats compared to controls in two of three trials (Trial 1 VE/VCO2: Nicotine exposed, 106.8±20.6 mL/min/100g, Control, 79.8±5.1 mL/min/100g, p=0.049; Trial 3 VE/VCO2: Nicotine exposed, 101.6±9.9 mL/min/100g, Control, 68.1±10.9 mL/min/100g, p=0.007). Overall, these results suggest that chronic nicotine exposure triggers plasticity in the chemoreflex pathway mediating the HVR in a sex specific manner and further studies are warranted to understand the implications of this finding.

1K99HL164973-02.

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.
A proteome perspective on adaptive responses to physiological challenges in marine mammals
Authors: Khudyakov Jane
Published: May 2024

While most mammals decrease energy expenditure while fasting, marine mammals such as northern elephant seals fast for several months while undergoing energy-intensive life history stages (e.g., postnatal development, molting, reproduction). Energy for these functions is provided by mobilization of large energy stores in blubber, which is driven by elevation of stress hormone levels across the fast. We used a proteome approach to examine potential mechanisms regulating fasting metabolism and responses to experimental stress challenges in elephant seals. We compared five proteome datasets and identified proteins that were altered by both fasting and experimental stress challenges across multiple life history stages and tissues in seals. These included lipid and hormone transport proteins (e.g., apolipoproteins, corticosteroid-binding globulin, transthyretin), acute phase proteins (e.g., alpha-2-macroglobulin, haptoglobin), antioxidant enzymes (e.g., glutathione peroxidase 3, catalase), adipokines (e.g., mimecan), and metabolic enzymes (e.g., fatty acid synthase, long chain fatty acid CoA ligase), among others. We suggest that these proteins may function as part of a core adaptive responses to physiological challenges in marine mammals. However, our ability to identify components of these responses has been hindered by several practical and technical challenges, and we will discuss the limitations and considerations for using a proteome approach in comparative physiology studies based on our experience.

This research was funded by University of the Pacific and Offce of Naval Research.

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.
Using Hissing Cockroaches to Teach Animal Physiology: Course Based Undergraduate Research Experiences
Authors: Contreras Heidy
Published: May 2024

Early student engagement in research has been shown to improve several student outcomes such as critical thinking, problem-solving and increased confidence in scientific aptitude. However, providing every student with access to traditional research experiences is diffcult. Course-based undergraduate research experiences (CUREs) are a good alternative to traditional research experiences since they are designed to provide students with hands-on research opportunities in scientific inquiry. CUREs have been shown to be a more inclusive entry point to scientific research as they break down barriers faced by many students, especially those faced by underrepresented first generation college students. Student's that participate in CUREs have shown gains similar to those obtained from traditional research experiences including improved research skills, self-effcacy, and an intent to persist in science. In this study, we developed a CURE in an Animal Physiology course at the University of La Verne, a small HSI liberal arts college in Southern California. As part of this CURE, students were trained on handling hissing cockroaches, and worked on this model systems to answer a question on the effects of different environmental factors on the metabolic rates of these ectotherms. Students developed their own hypothesis, designed an experiment, collected and analyzed data, drew conclusions, and presented their findings through an oral presentation. We measured student learning outcomes and affective student gains.

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.
The impact of eosinophilia on high fat diet-induced obesity and airway hyperresponsiveness
Authors: Proskocil Becky , Calco Gina , Jacoby David , Fryer Allison , Nie Zhenying
Published: May 2024

Hypothesis/Rationale: Eosinophils contribute to both adipose tissue metabolic homeostasis in obesity and airway hyperresponsiveness in asthma, but the role of eosinophils in obesity-related airway hyperresponsiveness is not understood. Considering that metabolic disorders increase the susceptibility to airway hyperresponsiveness in obese individuals, we investigated whether adipose eosinophils play a protective role in obesity-related airway hyperresponsiveness. Methods: Wild type (WT) and transgenic mice that overexpress interleukin 5 in peripheral T cells (+IL5T) were fed a high fat (61.6% fat) or normal chow (13.6% fat) diet for 19 weeks. Body weight, body fat, fasting glucose and insulin, and bronchoconstriction in response to inhaled serotonin were measured. The number of eosinophils were counted using flow cytometry in lung, adipose, and blood from transgenic WT and +IL5T mice with GFP-expressing eosinophils. Data: High fat diet significantly increased body weight and body fat in both WT and +IL5T mice, however +IL5T mice gained less weight and body fat than the WT mice. High fat diet increased fasting glucose, fasting insulin, and nerve-mediated airway responsiveness to inhaled serotonin in only the WT mice. On a normal chow diet, +IL5T mice had significantly more eosinophils in lung, blood, and adipose, and high fat diet further increased eosinophils in +IL5T adipose tissue. Acute administration of 1.29 U/kg (i.p.) insulin to a WT mouse on a normal chow diet significantly potentiated airway hyperresponsiveness to inhaled serotonin. Summary of results: Eosinophils in adipose tissue prevented high fat diet increases in circulating glucose and insulin, resulting in less body weight and body fat. This reduction in insulin by eosinophils in adipose tissue prevented obesity-related airway hyperresponsiveness. Conclusions: Insulin is a key modulator of obesity-related airway hyperresponsiveness. Eosinophils in adipose tissue play an important role in preventing obesity-related airway hyperresponsiveness by modulating insulin levels.

Funding: NIH HL164474, NIH HL163087.

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.