bluuebunny/crossref_metadata_2025 huggingface dataset:
Specific Microbiome Signature Dynamics Could Predict Aging Continuum and Cognitive Impairment in Older Adults
Authors: James Adewale S. , Chaudhari Diptaraj S. , Jain Shalini , Goltz Dayna , Tangudu Divyani , Yadav Hariom , Consortium MiaGB
Published: May 2024

The global population is aging, facing a substantial burden of age-related disorders, including cognitive impairment (CI), Alzheimer's disease (AD), and related dementias (ADRD). The lack of effective strategies for preventing and treating these conditions can be attributed to our incomplete understanding of the biology of aging. Emerging evidence strongly suggests that the gut microbiome plays a pivotal role in aging and its association with cognitive decline and ADRD. Yet, the transformations occurring within the microbiome during the aging continuum remain insuffciently studied. We have addressed these significant knowledge gaps by analysing samples and data from 176 older adults participating in the multi-site Microbiome in Aging Gut and Brain (MiaGB) consortium. Whole-genome metagenomic analysis unveiled distinct microbiome profiles among three aging categories: (i) 60-69 (n=62), (ii) 70-79 (n=78), and (iii) 80+ (n=36), spanning from phyla to species-level phylogeny. Notably, in older adults, changes in the microbiome were observed with respect to the aging continuum and cognitive impairment (CI). The abundance of Lachnospiraceae, Eggerthellaceae, Dorea, Blautia, and Eggerthella decreased, while Veillonellaceae increased in the gut of older adults with CI but not within the aging continuum. Interestingly, only Proteobacteria, Firmicutes, Candidatus melainabacteria, Coriobactericeae, Ruminococcaceae, Anerostipe hadrus, and Collinsella aerofaciens decreased, while Bacteroidetes, Bacteroidiceae, and Bacteroides uniformis increased within the aging continuum but were not impacted in CI sub-groups. However, both Ruminococcus torques and Streptococcus thermophilus decreased with aging continuum and CI. These results indicate unique microbiome changes specific to the aging continuum, as well as distinct changes with CI, independent of age. Thus, they not only hold promise as prognostic markers for assessing the risk of cognitive decline and dementia in older adults but also pave the way for designing precision microbiome interventions to mitigate the risks posed by these debilitating public health issues.

We thank the Ed and Ethel Moore Alzheimer’s Disease Research Program, Florida Department of Health (22A17), National Institutes of Health, National Institute of Aging (R56AG069676, R56AG064075, RF1AG071762, R21AG072379, U01AG076928), and Department of Defense (W81XWH-18-PRARP AZ180098) for funding support.

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.
Isotope-guided metabolomics dissects kidney arginine metabolism
Authors: Chrysopoulou Maria , Jägers Johannes , Bleich Markus , Himmerkus Nina , Rinschen Markus
Published: May 2024

Background: L-arginine is a key amino acid for detoxification, protein metabolism, and kidney and cardiovascular health. In the urea cycle, ammonia is incorporated into urea through the transformation of arginine to ornithine and urea, a reaction that occurs mostly in the liver but also in the kidneys. Hypothesis: An imbalance of kidney arginine metabolism can be associated with kidney injury. Aim: To detect the arginine uptake and its metabolic fate in kidney in vivo and ex vivo models by metabolic flux analysis. Method: Healthy C57BL/6 mice (n=22) were fed with normal and 13C6-15N4-arginine diet for 1, 2 and 8 weeks. Extracted metabolites from kidney cortex and medulla were analyzed with UHPLC/QQQ-based mass spectrometry targeting arginine-related metabolic pathways: the urea cycle, polyamines, the nitric oxide pathway, arginine/proline/glutamate interconversion, as well as modified forms of arginine. Additionally, micro-dissected nephron segments (glomeruli, proximal convoluted tubules (PCT), proximal straight tubules (PST), thin ascending limb of the loop of Henle (TAL), distal convoluted tubules (DCT), collecting ducts (CD)) from 4 healthy C57BL/6 mice, were incubated with 13C6-arginine and analyzed accordingly. Results: Isotope tracing allowed us to follow the fate of arginine in the kidney cortex and medulla of the 13C6-15N4-arginine-fed animals. The ex vivo experiments confirmed that all nephron segments take up and metabolize arginine, except for the TAL. More specifically, ornithine was found in all segments apart from the CD. Agmatine was formed in the PST and the CD, whereas arginine contributed to the proline and glutamine formation in the glomeruli, the PCT and the CD. Methylated forms of arginine were observed in the PST and the DCT. Conclusion: This study enabled the detection of arginine-related metabolites inside the kidney and showed that the metabolic fate of arginine differs along the nephron. The detailed isotope-based arginine metabolic flux and its role in kidney disease models will be determined next.

This work is supported by the Young Investigator Award from the Novo Nordisk Foundation (grant number NNF19OC0056043), awarded to Markus Rinschen.

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.
Dysfunction of M channels in the insular cortex is involved in pathogenesis of primary hypertension
Authors: Li De-Pei , Sheng Zhao-Fu , Zhang Hua , Zheng Peiru
Published: May 2024

Heightened sympathetic nerve activity is critically involved in the pathogenesis of primary hypertension. However, the sources driving increased sympathetic vasomotor tone remain unclear. The posterior insular cortex (PIC) is a brain region involved in regulating blood pressure and sympathetic tone. Neurons in the PIC project to the rostral ventrolateral medulla (RVLM), a key brain stem region in regulating sympathetic nerve activity and blood pressure. The non-inactivating voltage-dependent K+ channels, M channels (Kv7/KCNQ channel family) encoded by KCNQ2/3 genes, play a unique role in stabilizing the neuronal membrane potential and regulating neuronal excitability. Here, we determined if the M channel activity of neurons in the PIC is altered in a primary hypertension. Compared with Wistar-Kyoto (WKY) rats, the mRNA and protein expression levels of Kv7.2/Kv7.3 in the PIC tissue were significantly reduced in spontaneously hypertensive rats (SHRs). Microinjection of M channel blocker 10, 10-bis (4-pyridinylmethyl)-9(10H)-anthracnose (XE-991) into the PIC increased arterial blood pressure (ABP) and renal sympathetic nerve activity (RSNA) in anesthetized WKY rats, while induced minimal changes of ABP and RSNA in SHRs. M currents recorded from PIC neurons in brain slices labeled by retrograde tracer, Fluospheres, injected into the RVLM were significantly smaller in SHRs than in WKY rats. Furthermore, bath application of specific M channel blocker XE-991 increased the firing rate of PIC-RVLM output neurons in WKY rats while caused a minimal increase in firing rate of PIC-RVLM output neurons in SHRs. In addition, M currents recorded from PIC-RVLM output neurons in SHRs were significantly smaller than those recorded from WKY rats. These data suggest that M channel activity is diminished in PIC-RVLM output neurons in SHRs, and the diminished Kv7 channel activity contributes to elevated sympathetic outflow in primary hypertension. This novel information provides new a mechanistic insight into the pathogenesis of neurogenic hypertension.

Supported by grants from National Institutes of Health (HL139523, HL142133, and HL159157 to DPL).

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.
Gut bacteria contribute to rodent hypertension via modulation of colonic serotonin and gut vagal 5ht3aRs
Authors: de Araujo Alan , deLartigue Guillaume , Zubcevic Jasenka
Published: May 2024

Hypertension is associated with gut dysbiosis and autonomic dysfunction in humans and rodent models. While hypertension-associated gut dysbiosis elevates blood pressure in rodents, the precise mechanisms are unknown. In our model gut dysbiosis-induced hypertension, fecal matter transplant from hypertensive SHR reduced colonic serotonin and relative expression of serotonergic 5ht3a receptors (5ht3aRs) on vagal afferents in the control WKY rats. To investigate the role of serotonergic gut vagal axis in regulation of blood pressure, in a cre-dependent manner we first overexpressed channelrhodopsin 2 in the 5ht3aR-expressing gut-projecting vagal afferents (NG5ht3Ar) in 5ht3aR Cre rats. Acute bilateral optic stimulation of NG5ht3Ar produced an immediate decrease in blood pressure and heart rate. Conversely, chronic ablation of NG5ht3Ar by cre-dependent expression of caspase elevated blood pressure in 5ht3aR Cre rats. This effect was potentiated both by the infusion of low dose of angiotensin II and exposure to acute restraint stress separately. On the other hand, overexpression of 5ht3aRs in NG5ht3Ar reduced blood pressure in the SHR, the effect that was further potentiated by dietary tryptophan supplementation. Altogether, these data propose that hypertension-associated microbiota contribute to rodent hypertension via modulation of colonic serotonin and gut vagal 5ht3aRs.

NIHR01HL152162.

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.
Bmal1 Knockout in Rats Results in Hydrocephalus and Behavioral Defects
Authors: Grady Caroline , Andrade Cavalcante Moraes Yaslle , Holland Marshall , Becker Bryan
Published: May 2024

Circadian rhythms drive many aspects of physiology including brain water homeostasis with increased cerebral spinal fluid flow and brain parenchyma clearance during periods of sleep. Our group has previously reported maintained diurnal rhythms in blood pressure and renal function in rats lacking the core clock gene, ARNTL, or Bmal1. However, we have also observed a robust increase in brain water content and blood brain barrier permeability in knockout rats compared to wildtype (WT) controls. Patients with normal pressure hydrocephaly (NPH) display a triad of symptoms including memory dysfunction, gait disturbances, and urinary incontinence. We hypothesized that the Bmal1 knockout (Bmal1 KO) rat has behavioral symptoms similar to those seen in NPH patients. In an initial series of behavioral tests, we utilized open field and rotarod testing to measure exploratory behavior and locomotion. Following a training trial, male and female rats were tested over 4 different trials performed on sequential days. In 10 minute open field tests, Bmal1 KO rats had a trend toward decreased total movement compared to WT (1980 ± 185 vs 2369 ± 144 cm; p = 0.1430; n = 5 and 6 respectively). Anxiety-like behavior was pronounced in the Bmal1 KO rats compared to WT as evidenced by lower frequency of entries (3.6 ± 0.7 vs 11.0 ± 2.0 entries; p = 0.0098) and decreased time spent (8.0 ± 2.4 vs 25.4 ± 5.6 seconds; p = 0.0261) in the center zone of the open field. Rotarod testing of ramps from 0 to 16.5 cm/s over 5 minutes uncovered a strong trend towards decreased average distance ran (937 ± 256 vs 1540.0 ± 176 cm; p = 0.0775) and max velocity achieved (11.1 ± 1.5 vs 14.5 ± 0.8 cm/s; p = 0.0666) in Bmal1 KO compared to WT. Bmal1 KO rats also had more falling events on the rotarod compared to WT (0.95 ± 0.04 vs 0.73 ± 0.6 falls/trial; p = 0.0098). These findings indicate that in addition to the overt hydrocephalus phenotype of Bmal1KO rats and increased blood brain barrier permeability, lack of Bmal1 induces behavioral and locomotor symptoms similar to those seen in human patients with NPH. We propose that the Bmal1 KO rat can serve as a pre-clinical model for NPH and other forms of hydrocephalus and will shed light on mechanisms of altered central fluid flow that are present in many neurodegenerative diseases associated with aging.

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.
CD4+ T Cells from Women with Preeclampsia During Pregnancy Contribute to Hypertension, AT1-AA, and Neurovascular Dysfunction in a Pregnant Rat Model of PE
Authors: Campbell Nathan , Simmons Kimberly , Herrock Owen , Deer Evangeline , Morris Rachael , Turner Ty , Amaral Lorena
Published: May 2024

Objective: Preeclampsia (PE) is characterized by new onset hypertension (HTN) during pregnancy and is associated with activated CD4+ T cells and agonistic antibodies against the angiotensin II type 1 receptor (AT1-AA). Interestingly, having had COVID-19 during pregnancy is associated with increased incidence of a PE-like phenotype. Both PE and CV have long lasting neurological implications. We sought examine a role for CD4+ T cells from PE with or without a CV Hx to contribute to a PE phenotype and neurovascular dysfunction postpartum (PP). Methods: We utilized adoptive transfer of one million placental CD4+ T cells from PE and normotensive (NT) patients with or without a CV (Hx) during pregnancy injected i.p. into gestational day (GD) 12 nude athymic rats athymic and determined neurological consequences at 12 weeks PP. At GD19, blood pressure (MAP) and AT1-AA were measured. At 3 months PP, memory and error in navigation were assessed by Barnes maze consecutively for 5 days. CBF was measured by laser Doppler flowmetry. A two-way ANOVA was used for statistical analysis. Results: In pregnant recipient rats, MAP increased in CV Hx PE (113±2, n=8) and PE (115±2 mmHg, n=10) compared to CV Hx NT (104±4, n=7) and NT (98±2 mmHg, n=7 p<0.05). AT1-AA increased in PE (8±2 ΔBPM, n=4) and CV Hx PE (4±2 ΔBPM, n=4) compared to NT (-3±2 ΔBPM, n=4, p<0.05) and CV Hx NT (2±2 ΔBPM, n=2) respectively. At 3 months PP, PE and CV Hx PE had impaired CBF autoregulation compared to CV Hx NT and NT rats, and both PE groups exhibited greater mistakes and latency in maze navigation, however, the scores were worse in those receiving T cells from PE patients without a Hx of CV compared to all other groups. Conclusion: Our findings indicate that pregnant recipients of CD4+ T cells from PE with or without a CV Hx during pregnancy cause HTN and increased AT1-AA compared to recipients of NT or NT Hx CV-19 CD4 + T cells. Interestingly, recipients of T cells from PE patients without a Hx of CV had worse CBF and cognitive function at 3 months PP, demonstrating the importance of CD4+ T cells in HTN and impaired neurological function during pregnancy PP in patients with previous PE.

This study was supported by NIH grants RO1HD067541 (BL), F31HD110230 (NC), P20GM121334 (BL, LMA), and American heart association (AHA) early career award 19CDA34670055 (LMA).

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.
Identifying and Responding to Gaps in Services for International Graduate Students and Postdoctoral Fellows to Enhance the Graduate Community and Promote Quality Research Outcomes
Authors: Crider Emily A , Dent Elena , Sullivan Jennifer C
Published: May 2024

The growing enrollment of international students in doctoral science, technology, engineering, and mathematics (STEM) programs in the U.S. has contributed to the need for an increase in specifically-designed programs, resources, and services that address the unique challenges of the international student population. When transitioning to the U.S. to pursue higher education, international students often experience obstacles, including language barriers, sociocultural challenges, and academic alienation, which significantly impacts the ability to successfully adapt to the new learning and living environment, oftentimes continuing throughout the duration of the program. Furthermore, international postdoctoral fellows engaged in STEM research fields may lack a sense of belonging due to similar barriers. The recruitment and retention of competitive international students and postdoctoral fellows directly impacts the quality and magnitude of research outcomes, while also enhancing and enriching the cultural diversity and experience of the graduate community. We use data collected from an international student and postdoctoral survey distributed to more than 65 students and 90 postdoctoral fellows as well as listening sessions to identify gap areas where additional resources are required and where modifications are needed to more productively serve the international population at Augusta University. Our findings indicate that international students and postdoctoral fellows experience more anxiety and isolation when they are not supported, personally, socially and academically, by their administrative leaders, faculty, peers, and surrounding community. Incoming students who were connected with current graduate students prior to their arrival to the U.S. experienced a greater level of support and were more confident and comfortable in their adjustment to society in the U.S. The implementation of additional events and experiences led by the responses of the international population, including research shadowing opportunities in on-campus laboratories, social gatherings connecting students and postdoctoral fellows of different cultures, writing circles and professional development workshops, and one-on-one sessions enhances community belonging and prioritizes personal and professional growth among this vulnerable student population.

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.
Vascular Signaling Plasticity Reprograms Blood Delivery Mechanisms to Meet Fluctuating Neuronal Energy Needs
Authors: Weir Nick , Xiang Liuriumin , Vigderman Abigail , Isaacs Dominic , Qadir Houman , Patton Michael , Mathur Brian
Published: May 2024

Neuronal computation is metabolically expensive and depends on precision delivery of energy substrates—oxygen and glucose—via tightly coordinated blood flow to ensure that energy demands are continually met. This is facilitated by neurovascular coupling (NVC)—a range of mechanisms matching neural activity to local blood flow. These NVC mechanisms are typically considered invariant, and whether they are reshaped according to ever-changing neuronal metabolic needs has not been examined. We present evidence that neural activity continually reprograms the blood flow control mechanisms embedded in the local vasculature, a process we refer to as ‘vascular signaling plasticity’ (VSP). Using an established enrichment paradigm, we find that animals housed in conditions that increase input to the barrel cortex for 7 days exhibit profound neuronal plasticity in this region. This resculpts local vascular reactivity to elevate blood delivery. Indeed, VSP results in increased basal capillary blood flow and augmented activity of vasodilatory agents in vivo manifesting as increased red blood cell (RBC) flux responses to capillary stimulation and upstream diameter changes measured using 2-photon laser scanning microscopy. Moreover, the sensitivity of capillaries to stimulation is also dramatically elevated in an ex vivo isolated capillary-arteriole preparation. Using K+-mediated capillary-to-arteriole electrical signaling as a springboard to study the molecular underpinnings of VSP, we find that this process induces a ~70% increase in the density of strong inward rectifier K+ (Kir2.1) currents in capillary endothelial cells, which profoundly augments the retrograde hyperpolarization generated by these channels to control upstream diameter at the level of the penetrating arteriole. Through whole-cell patch clamp electrophysiology, we characterize the mechanism of VSP induction and recapitulate this phenomenon in vitro. We validate our findings through Crispr/Cas9-mediated endothelial cell-specific knockout of the transcription factor responsible for VSP induction. Our data thus recast the vasculature as a plastic, brain-wide activity sensing network that is continually reshaped at the molecular level by local neuronal input, leading to precisely-tuned blood delivery to meet continually fluctuating neural energy needs. VSP represents a new dimension to brain plasticity that may underpin a range of vital physiological processes and is likely disrupted in numerous brain pathologies with a blood flow component.

This work was supported by the American Heart Association (23POST1023086), and NIH grants 1DP2NS121347, 1R01AG066645, and 5R01NS115401.

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.
Sex Is Not a Transcriptomic Binary: Towards a Broad Physiologic Omics Insight Into Sex Chromosome Genes
Authors: Das Akansha , Bhargava Disha , Prokop Jeremy
Published: May 2024

Background: As social definitions of sex and gender expand, there is a greater demand for understanding the clinical challenges of intersex individuals, transgender individuals, and those with hormonal and transcriptomic profiles that do not align with traditional binary standards. Larger population studies are elucidating comorbidities associated with Klinefelter’s Syndrome, Turner’s Syndrome, 47XXX, 47XYY, and other sex chromosome syndromes even though the sex chromosomes are underpowered in traditional GWAS. Though research has focused on how estrogen and testosterone supplementation can influence comorbidity risk, we identify a need for greater understanding of isoform and tissue-specific expression and functions of X and Y genes to understand their potential interactions with hormones and inform physiological outcomes. Methods: Analysis of RNA-Sequencing data quantified in transcripts per million (TPM) from GTex (extracted June 2022, n = 17,382), NCBI SRA Blood PAXgene tube analysis (extracted June 2021, n = 12,559), and NCBI SRA “skin” RNA sequencing (extracted June 2021, n = 8,274). Results: We display an expression panel of 572 isoforms of 73 sex-biased genes across 54 male (n = 11,588) and female (n=5,798) tissue samples and highlight isoform-specific expression differences within the brain, arteries, heart, skeletal muscle, and gastrointestinal tract. Six X/Y gene pairs show broad ratios over tissues highlighting the role of X-chromosome dosage and X-chromosome inactivation escape differences in various tissues. Several genome-wide eQTLs across multiple tissues have sex differences and are found within X/Y chromosome transcription factor binding sites such as ZFX/ZFY. Stratifying blood and skin RNA-Sequencing data by XIST/KDM5D ratios to determine transcriptomic “sex”, we conduct an exploratory analysis of bioprojects with five or more outliers of X:Y chromosome expression ratios (Males: PRJNA683803 (HIV), PRJNA768419 (Sepsis), PRJNA492829 (Vaccine trial), PRJNA496323 (Psoriasis and atopic dermatitis), PRJNA699562 (COVID-19). Females: PRJNA683803 (HIV), PRJNA794277 (Sepsis), PRJNA492965 (Vaccine trial), PRJNA526259 (Myalgic encephalomyelitis)).Conclusion: Transcriptomics enables broader insights to sex chromosomes and their contributions to physiology outside of the binary male/female knowledge.

This work was supported by the NIH NIAID and OD grant R01AI171984.

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.
Pathway analysis for functional characterization of microRNAs
Authors: Hatzigeorgiou Artemis , Skoufos Giorgos , Miliotis Marios
Published: May 2024

DIANA-miRPath webserver enables the exploration of combined miRNA effects using predicted or experimentally supported miRNA interactions. Its latest version (DIANA-miRPath v4.0, http://www.microrna.gr/miRPathv4 ), introduces the capacity to tailor its target-based miRNA functional analysis engine towards specific biological/experimental contexts. Via a modular interface with rich interaction, annotation and parameterization options, users can perform enrichment analysis on Gene Ontology (GO) terms, KEGG and REACTOME pathways, gene sets from Molecular Signatures Database (MSigDB) and PFAM. Included miRNA interaction sets are derived from state-of-the-art resources of experimentally supported (DIANA-TarBase v8.0, miRTarBase and microCLIP cell-type-specific interactions) or from in silico miRNA-target interactions (DIANA-microT-2023 and TargetScan predictions). Bulk and single-cell expression datasets from The Cancer Genome Atlas (TCGA), the Genotype-Tissue Expression project (GTEx), as well as single-cell expression atlases can be used to assess expression change of targeted genes within terms, across a wide range of states. A discrete module to perform miRNA-tailored CRISPR knock-out screen analyses deems possible the investigation of selected miRNAs within conditions under study.

Hellenic Foundation for Research and Innovation (HFRI) under the 1 st Call for HFRI Research Projects to Support Faculty Members & Researchers and Procure High-Value Research Equipment grant (Project Number 2563).

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.
IL-6 Contributes to Impaired Nitric Oxide and Increased Mitochondrial ROS Production in Human Aortic Endothelial Cells
Authors: Velusamy Prema , Greaney Jody L. , Case Adam J. , Fadel Paul J. , Trott Daniel W.
Published: May 2024

Background: Major Depressive disorder (MDD) is associated with chronic low-grade inflammation with elevated proinflammatory cytokines. Notably, elevated inflammation is a known contributor to cardiovascular dysfunction and disease. Interleukin (IL)-6 has been shown to be elevated in rodent models of depression. Additionally, preliminary data from our lab suggests that there is a greater proportion of IL-6 producing CD8+ T cells in adults with MDD. Although IL-6 has been reported to be increased in adults with MDD and known to have a direct effect on vascular endothelial cells, the exact mechanism by which IL-6 interacts with the endothelium is unknown. Therefore, we tested the hypothesis that IL-6 treatment will decrease nitric oxide (NO) production and increase mitochondrial ROS (mitoROS) in endothelial cells. Methods: Human aortic endothelial cells (HAECs) were used to study the effects of IL-6 on NO production. The HAECs were treated with vehicle or 10 ng/mL IL-6 for 16 hours, and then stimulated with Acetylcholine to induce NO production and the real time NO production was measured using a commercially available assay. We also measured mitoROS in HAECs treated with or without IL-6. Results are expressed as mean ± SEM (n=3-6 replicates) and group differences were assessed by one-way ANOVA followed by Tukey’s post-hoc test. Results: L-6 was found to significantly lower NO production in the cells (Control: 276.24 ± 7.01; IL-6: 215.19 ± 6.07 MFI, p=0.022). Acetylcholine stimulation resulted in greater NO production in the control cells (Control: 276.24 ± 7.01; Control + Ach: 354.28 ± 6.26 MFI, p=0.0005) whereas this increase was abolished in the IL-6 treated cells (IL-6: 215.19 ± 6.07; IL-6 + Ach: 225.21 ± 5.16 MFI, p=0.955). Additionally, we also found greater mitoROS in the IL-6 treated cells (Control: 683.02 ± 32.98; IL-6: 840.86 ± 38.63 MFI, p=0.002). Conclusion: These preliminary results suggest that IL-6 reduces NO production in endothelial cells, which may be in part due to elevated mitoROS.

This work is supported by grants from NIH K01AG061271, R01AG060395 and AHA940023 (DWT).

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.
Links between systemic inflammation and the chemoreflex control of breathing following COVID-19
Authors: Penuelas Veronica , Pham Kathy , Frost Shyleen , Harahap-Carillo Indira , Vargas Abel , Bergersen Kristina V. , He Yuxin
Published: May 2024

The emergence of SARS-CoV-2 resulted in millions of hospitalizations and 6.9 million deaths to-date. Many individuals who recover from COVID-19 report prolonged dyspnea, with this symptom persisting for months following recovery. Furthermore, data suggests COVID-19 has been linked to systemic and neuronal inflammation which may have downstream impacts on the neural control of breathing. As such, we hypothesized that individuals recovered from COVID-19 may exhibit changes in their ventilatory chemosensitivity to CO2 and/or O2 and that these changes may be linked to higher levels of systemic inflammation. To test this hypothesis, we measured baseline ventilatory patterns and chemoreflex sensitivity using a modified rebreathing technique in individuals recovered from COVID-19 (n = 77), as well as an age and sex-matched control group (n = 41). Peripheral blood samples were also collected for inflammatory profiling. Recovered participants demonstrated lower ventilatory responses to hypercapnia, particularly under a combined hypoxic stimulus (p = 0.032). Furthermore, higher levels of plasma IL-1β and IL-6 were associated with lower hypoxic ventilatory responses (R2 = -0.53, p = 0.025; R2 = -0.49, p = 0.04), highlighting a potential link between systemic inflammation and ventilatory chemoreflex sensitivity. When separated by time-post-recovery, we observed a decreased ventilatory recruitment threshold (VRT) beginning at 4 months post-recovery (p = 0.019) that returned to baseline after one-year post-recovery. A decrease in sensitivity to CO2 was also noted immediately after recovery with no return to baseline observed within the two-year tested time frame (p = 0.023). Overall, this data indicates that (1) COVID-19 may have impacts on the neural control of breathing, and (2) systemic inflammation may play a role in modulating ventilatory chemoreflex sensitivity. These findings may have implications for the pathology of long-COVID symptoms, including sleep disturbance and prolonged dyspnea.

This work was funded by the Health Disparities Research Center and the OASIS center at University of California, Riverside.

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 Role for the Gastrointestinal Tract in Sodium Dysregulation Associated with the Salt Sensitive Phenotype in the Dahl S Rat
Authors: Otmanowski Emily , Keith Caullin , Bearss Nicole , Joe Bina , Reznikov Leah , Zubcevic Jasenka
Published: May 2024

Introduction: Salt sensitive hypertension in the Dahl S rat (SS) has traditionally been attributed to elevated renal sodium reabsorption, largely mediated by the renal epithelial sodium channel (ENaC). Considering the role of ENaC in the distal colon epithelium in sodium absorption in the gastrointestinal tract, we hypothesized that the salt sensitive phenotype of SS rats may in part be attributable to increased absorption of sodium in the distal colon. Methods: Adult male SS and its control, the SR rats (12-14wo), were administered either low sodium diet (LS; 0.3% NaCl, Teklad) or moderately high sodium diet (HS; 2.0% NaCl, Teklad) ad libitum for two weeks. At endpoint, fecal samples were collected, dried for 72 hours at 70°C, weighed, and homogenized in deionized water. Fecal levels of sodium per gram of dry fecal weight were measured using flame photometry. Segments of distal colon wall were dissected and mounted in the Ussing chamber filled with warm, oxygenated Kreb’s solution containing D-glucose. Amiloride hydrochloride, a selective ENaC inhibitor, was applied to the tissue apical side in increasing concentrations (0-100μM) at 10-minute intervals. Total ionic currents (Isc, A) were measured under voltage clamp and presented as change from baseline. Results: We observed significantly lower fecal sodium levels in the SS compared to SR rats on LS diet (p<0.05), and a similar trend in fecal sodium levels between the SS and SR on HS diet (P=0.1). This was associated with significantly elevated amiloride-sensitive current in the distal colon of SS compared to the SR on LS and HS diets (p<0.01 and p<0.0001, respectively). Conclusion: Elevated amiloride-sensitive sodium current in the distal colon of SS rats is associated with decreased fecal sodium levels. This suggests increased sodium absorption in the SS rats and proposes a role for the gastrointestinal tract in sodium dysregulation associated with the salt sensitive phenotype in Dahl S rats.

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.
Effects of CBD on the Phosphorylation of Cardiac Insulin Receptor in Rat Model of Metabolic Syndrome
Authors: Zapet Bamac Daisy , Wilson Jessica , Mendez Dora A. , Ortiz Rudy M.
Published: May 2024

Metabolic syndrome (MetS) comprises a cluster of conditions that include obesity, insulin resistance, dyslipidemia, hypertension, pro-inflammation, and pro-thrombosis. In the United States, approximately one in three adults is afflicted with MetS. If left unmanaged, it can lead to type 2 diabetes (T2D), which would increase the risk of cardiovascular diseases (CVD). The insulin signaling pathway is critical to regulate glucose homeostasis in the body. During insulin resistance, the pathway is downregulated, and glucose remains in the bloodstream leading to a hyperglycemic state. Recent studies on the benefits of cannabidiol (CBD) have shown it can mitigate CVD risk factors, but its impact on glucose metabolism within the heart remains unclear. To investigate this, the Otsuka Long Evans Tokushima Fatty (OLETF) rat, a model of MetS, and its healthy strain-control, the Long Evans Tokushima Otsuka (LETO) rat, were used. Rats were assigned to three groups (n=8/group): (1) untreated LETO, (2) untreated OLETF, and (3) OLETF + H4CBD (200mg/kg/day x 4 weeks). CBD treatment did not impact the nascent insulin receptor nor the nascent protein kinase B, but the effects of CBD on the phosphorylation and activation of these insulin signaling components have yet to be determined (analyses ongoing). Because CBD has been shown to improve glucose homeostasis previously, we anticipate it is by increasing the activation by phosphorylation of the insulin receptor. A better examination of the effects of CBD on the insulin signaling pathway in the heart will provide greater insight on its therapeutic potential during diabetic cardiomyopathy.

USDA Hispanic Education Training Program, Center for Medical Cannabis 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.
Assessments from the first year of an underrepresented undergraduate internship program
Authors: Barnett Vincent , Wu Steven , Anderson Lisa
Published: May 2024

To enhance our service to a diverse student population our faculty created the INtegrative biology and Physiology Undergraduate Training (INPUT) program. This research focused initiative solicited applications from first- and second-year students undergraduates of our large, urban, land-grant university. Selection criteria included academic aptitude, self-reported socioeconomic and cultural challenges, interest in physiological research and letters of support. Six students were selected from our initial cadre of applicants. The students were matched with faculty research mentors and provided a paid research opportunity for the spring semester of 2023. At the end of the term, an assessment of the experience by both each student and mentor determined whether a second semester experience was offered by the department. All of our faculty mentors were favorably impressed by the progress made by their INPUT scholars and five of the six students requested and were granted a second semester research opportunity. The five INPUT students continued their mentored research in the areas of neurophysiology, skeletal muscle physiology, and adipose biology. The one outlier stated that while she enjoyed the experience and that it encouraged her to continue in research. She also found that her scientific passion was in chemistry rather than physiology and moved to a different program. Based on the overall positive outcomes a second semester opportunity was offered to the five students who expressed an interest in continuing their physiology-focused projects. The second term experiences were completed either during the summer or fall of 2023. We will encourage our initial group of INPUT scholars to serve as ambassadors for other underrepresented students who are interested in physiology research and use their end of experience assessments to help shape the future of our INPUT program. We will report on the opportunities discovered and the challenges faced in launching the INPUT program as well as the prospects for continued outreach. Our hope is that our experiences with INPUT will encourage others to attract, encourage and prepare a robust and representative group of young scientists and clinicians to enter the 21st century biomedical community.

Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN 55455.

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.
Mitigating Female Aging Kidney Damage from Ischemic Reperfusion Injury Using Renal Progenitor Cells
Authors: Parker Alexander , Pushpakumar Santhnur B , Sen Utpal
Published: May 2024

Acute kidney injury (AKI) is a sudden event that damages the kidney and disrupts normal function by various causes, such as ischemia, exposure to substances, or obstructions. With AKIs affecting 1 out of 5 hospitalized patients and their association with increased risk of chronic kidney disease (CKD), finding an effective treatment for AKIs is of vital importance. One possible treatment for AKIs could be found within the realm of progenitor cell therapy. Progenitor cells are currently used in the treatment of hematological diseases with the burgeoning information on their possible uses for other disorders. The purpose of this study was to determine whether there is a resident population of renal progenitor cells (RPCs) within the kidney and if these cells can be utilized as an effective treatment to mitigate aging AKI by decreasing inflammation through alteration of the M1:M2 macrophage ratio. This study utilized 75-78 weeks old C57BL/6J female mice to determine if RPCs can reduce the damage caused by ischemic reperfusion (IR)-induced AKI. Kidneys were harvested from young female (40 days old) mice and digested in collagenase type 1 to remove connective tissue. Cells were sorted by flow cytometry, positively selected for c-Kit using magnetic nanoparticles, and subsequently stained for Sca1 and Oct4. Aging female mice underwent renal IR injury (IRI) by clamping off the renal artery and vein for 27 minutes. Following reperfusion, the triple-positive cells were suspended in DMEM and injected into the kidney over the course of 8 minutes to reduce the possibility of pressure necrosis. A separate group of mice was injected with saline to serve as control. The mice were monitored for 3 days at which point kidney function was assessed and tissue harvested for biochemical analysis. Our results indicated an increase in inflammatory cytokines IL-17, NF-κB, and IL-6 in IRI mice which were mitigated with RPCs treatment along with an increase in anti-inflammatory marker IL-10. Furthermore, an increase in M1 macrophage markers was measured in IRI, and a trending increase in M2 macrophage markers in IRI animals treated with RPCs. The kidney function of IRI animals treated with RPC showed improvement compared to IRI control. In summary, we found a population of cells positive for three progenitor cell markers: c-Kit, Sca1, Oct4, and treating IRI aging female kidney with these cells reduced inflammatory markers along with an increase in kidney function, suggesting RPCs promote recovery from AKI by reducing inflammation.

Grant Support: DK116591.

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.
Intestinal Barrier Protection by Probiotic Lactobacillus-Associated Indoles in Caco-2 and Enteroids
Authors: Bala Ajitha , Dadala Rhema , Antonio Jayson , Suntornsaratoon Panan , Ambat Jayanth , Li Wei Vivian , Gao Nan
Published: May 2024

Gut bacteria generate from dietary tryptophan (trp) indole compounds, which act as potent signaling molecules intricately involved in the regulation of intestinal homeostasis and barrier integrity. Lactobacillus rhamnosus GG (LGG), a widely used probiotic, has demonstrated ability to restore the gut barrier in animal models of colitis and sepsis, as well as in children with irritable bowel syndrome. To investigate the hypothesis that LGG-derived indoles are responsible for its gut barrier-enhancing properties, we fed gnotobiotic mice trp-suffcient and trp-deficient diets. We then monocolonized them with LGG, using PBS gavaged mice as a control, and analyzed the ileal transcriptome by bulk RNA sequencing and both fecal and serum metabolomes by LC-MS. Using our novel bioinformatic tool METRCA, which correlates metabolites and gene networks, we uncovered an unexpected and substantial influence of indole spatial distribution on genes associated with gut integrity: some were significantly positively linked to tight junction (TJ) genes exclusively from the luminal side, some exclusively from the serum, and others from both. Specifically, we identified nine indoles—indole-acetamide (IAM), indole-carboxaldehyde (IAL), indole-3-lactic acid (ILA), indole-3-propionic acid (IPA), indole-3-acrylic acid (IAR), indole-3-carbinol (ICB), indole-acetic acid (IAA), indole-3-acetonitrile (IAN), and indole-3-carboxylic acid (ICA)—that demonstrated the potential to maintain gut barrier function. To assess their impact, we used a high-throughput system that measured permeability through transepithelial electrical resistance (TEER) and FITC-dextran (4 kDa) in polarized Caco-2 cells. By luminally challenging cells with Clostridium diffcile toxins (TOX), we induced barrier disruption to model leaky gut. Intriguingly, when applied luminally, IAA, IAN, ICA, and ILA rescued the TEER of Caco-2 cells exposed to TOX, while IAM, IAL, and ILA were effective when applied basolaterally, suggesting a strong polar component to their barrier repair capacity. FITC transport revealed a significant basolateral rescue effect of IAM and luminal rescue effect of IAA and ICA, indicating that different sets of indoles are required to repair the pore and leak pathways. Furthermore, we confirmed that basolateral IAM rescued FITC permeability and induced increased expression of TJ genes Tjp1 and Ocln in enteroids challenged with lipopolysaccharides. In summary, our research highlights the potential beneficial therapeutic application of certain indoles in repairing disrupted gut barriers.

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.
Characterization of Ano1 expressing cells in the mouse corpus cavernosum
Authors: Hannigan Karen , Fox Emily , Cobine Caroline
Published: May 2024

Background/objectives: Highly coordinated contraction and relaxation of smooth muscle cells (SMCs) is critical to penile function. The Ca2+-activated Cl− channel, Anoctamin-1 (Ano1) plays a role in this as antagonists of this channel inhibit contractile, electrical and intracellular Ca2+ activity. mRNA encoding Ano1 is highly expressed in whole rabbit corpus cavernosum (CC). Despite its significant contribution to erectile function, the specific cell type that expresses Ano1 has not been determined, with previous studies relying on morphological identification of cells alone. Atypical SMCs (ASMCs) expressing platelet derived growth factor receptor-a (PDGFRa; Pdgfra), myosin heavy chain ( Myh11) and Ano1 have been observed in the renal pelvis where they are thought to drive the activity in adjacent SMCs (Grainger et al. 2020; PMID: 32415739). Therefore, the objective of this study is to identify the cell type that expresses Ano1 in the CC. Methods: Cells were isolated from the CC of mice selectively expressing eGFP in PDGFRa+ cells (PDGFRa+-eGFP mice) and SMCs ( Myh11-eGFP mice). Cell suspensions were sorted using fluorescence activated cell sorting (FACS) and evaluated for expression of cell specific markers ( Pdgfra and Myh11) by qPCR. Enriched PDGFRa+ cells and SMCs were examined with ddPCR to determine the expression of Ano1. Protein expression was evaluated using immunofluorescent labeling of frozen CC sections with an antibody targeting Ano1. Results: FACS sorted Myh11-eGFP+ cells expressed Myh11 and Pdgfra. Sorting of PDGFRa-eGFP+ cells revealed two subpopulations, bright and dim. Examination of these two PDGFRa-eGFP+ subpopulations revealed that while both expressed similar levels of Pdgfra, the dim population also expressed Myh11 suggesting that these cells may be similar to ASMCs of the renal pelvis. ddPCR revealed that the PDGFRa-eGFP+ dim population had higher gene copy numbers of Ano1 compared to Myh11-eGFP+ cells. Immunofluorescent labeling of CC sections revealed that Ano1 protein was present in a subpopulation of PDGFRa+ cells. Conclusion: The data presented in this study demonstrates that Ano1 is expressed in mouse CC PDGFRa-eGFP+ dim populations that also express Pdgfra and Myh11; this is similar to ASMCs in the renal pelvis. Future directions include examining the relationship of PDGFRa-eGFP+ dim cells to SMCs and nerve terminals in the CC and to determine if these cells are also present in human CC. This cell population could represent a novel target for the treatment of erectile dysfunction in patients who do not respond to phosphodiesterase inhibitors.

Funding: AUA Research Scholar Award to KIH, NIH DK129528 to CAC, NIH P20GM130459 for imaging and molecular cores.

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.