bluuebunny/crossref_metadata_2025 huggingface dataset:
Intrarenal angiotensin II mediated ROCK1 activation promotes hypertension during chronic acidotic conditions
Authors: Aryal Dinesh , Jackson Keith
Published: May 2023

The newly reported model of experimental hypertension delineates the scope of chronic metabolic acidosis as a cause of hypertension. The observed mechanism to promote hypertension during the acidotic conditions are regulated by intrarenal angiotensin II (Ang II) and oxidative stress functioning synergistically. The present study investigates the role of Rho Kinase (ROCK1) in mediating intrarenal activation of Ang II and the renal cell oxidative state during the observed acidosis elicited hypertension. Chronic metabolic acidosis (CMA) was induced in male Sprague Dawley rats (100-150 g) by providing a weak acid solution of 0.28 M ammonium chloride (NH4CL) in tap water for 8 weeks. To confirm the rats were acidotic, blood pH was measured, while blood pressure was monitored weekly using tail-cuff. Rats were divided into five groups: Control (vehicle treated), CMA (acidotic), CMA+spironolactone (to evaluate aldosterone effect), CMA+captopril (to evaluate Ang II effect), and CMA+tempol (to evaluate free radical effect). Microdialysis probes were implanted to the rat’s renal compartments in each group to collect the interstitial fluid. ELISA was performed to quantifying the ROCK1 in all the dialysate samples. In the CMA rats, sustained elevation in the mean arterial pressure (MAP), associated with the significant decrease in blood pH was observed compared to the Control group over the 8 weeks. A significant decrease in MAP was observed in CMA rats treated with captopril and tempol, whereas spironolactone treatment caused no decrease in MAP as compared to the CMA group. The interstitial ROCK1 was significantly increased in the CMA group vs control but decreased significantly in the CMA+captopril vs CMA and CMA+tempol vs CMA groups respectively. This suggested the intrarenal ROCK1 is regulating the Ang II and ROS generation in the renal compartment. Overall, this supports our hypothesis that ROCK pathway and its interaction with intrarenal Ang II and oxidative stress plays a pivotal role in the pathogenesis of acidosis promoted hypertension.

VCOM Departmental funding

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
RAGE availability lessens the degree of dysfunctional mitochondrial bioenergetics following chronic secondhand smoke exposure
Authors: Campbell Kennedy , Curtis Katrina , Clarke Derek , Saito Erin , Bikman Benjamin , Arroyo Juan , Reynolds Paul
Published: May 2023

The receptor for advanced glycation end products (RAGE) is an immunoglobulin-type receptor abundantly expressed by lung parenchyma that coordinates inflammatory responses. We have previously described roles for RAGE following exposure to tobacco smoke (both primary and secondhand) and environmental diesel particulate matter. While inflammatory signaling, tissue remodeling, and pulmonary function have each been investigated, mitochondrial fitness that may underpin cellular health has not been characterized in a chronic exposure model. The current study assessed mitochondrial bioenergetics in RAGE knock out (RKO) and wild type (WT) mice exposed to 3 months of secondhand smoke (SHS) via a nose-only delivery system (Sireq Scientific, Montreal, Canada) or room air (RA). Select mice were also co-administered SHS and semi-synthetic glycosaminoglycan ethers (SAGEs) that inhibit RAGE/ligand interactions. We discovered that mitochondrial respiration was significantly decreased in WT+SHS mice compared to WT+RA following the addition of glutamate/malate, ADP, succinate, and FCCP. Each of these sequential substrates revealed less severe mitochondrial respiration compromise in RKO +SHS compared to WT+SHS mice, suggesting the absence of RAGE was sufficient to blunt waning mitochondrial fitness. Importantly, mitochondrial respiration was significantly improved in WT+SHS+SAGEs mice compared to WT+SHS mice. These results provide a snapshot of mitochondrial fitness following chronic SHS exposure and suggest a role for RAGE signaling in altering cellular bioenergetics during exposure.

This work was supported by funding from the National Institutes of Health (NIH 1R15-HL152257, PRR and JAA).

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Establishing a Rat Model of Intestinal Heme-iron Absorption
Authors: Lee Jennifer , He Yue , Shine Jacob , Ebea Pearl , Flores Shireen , Hamza Iqbal , Collins James
Published: May 2023

Heme iron, derived from hemoglobin and myoglobin of animal products, is efficiently absorbed and utilized by humans. Despite extensive investigation over the last several decades, the exact mechanism(s) of heme-iron absorption and tissue utilization of absorbed heme are unclear. Mice are frequently used for investigation of iron biology; however, mice do not efficiently utilize dietary iron derived from heme, so development of alternative models is warranted. Rats could more efficiently utilize dietary heme iron, but this has not been rigorously tested. Our initial studies demonstrated that dietary heme (derived from porcine RBCs) could partially correct iron-deficiency anemia (IDA) in rats of one strain (rat strain 1), but not in 2 others. We hypothesized that a heme-iron diet would fully replete strain 1 rats with IDA, at a similar rate to a non-heme iron (NHI) diet. We utilized repletion diets containing 50, 75 or 100 ppm heme iron; a control diet contained 50 ppm NHI. Forty-two, three-week-old, female strain 1 rats were weaned onto a low-iron diet with 3-4 ppm NHI, and then after 2 weeks, rats were repleted with the different diets for 8 days. Rats were housed in overhanging wire bottom stainless steel cages during the low-iron feeding period to prevent coprophagia. Blood was collected from the tail vein at baseline and every 4 days thereafter to track correction of anemia. Outcomes showed that repletion of IDA rats with the 50-ppm heme-iron diet resolved the anemia; however, tissue iron depletion indicated that the rats remained iron deficient. Also, the rate of repletion was slightly slower as compared to rats repleted with the control (50 ppm NHI) diet. With higher dietary heme-iron levels, repletion was as fast, or even faster, than in control rats suggesting that a rat strain was identified that can efficiently assimilate dietary heme iron. Our studies support a role for rats as a genetic model to preferentially mimic human nutritional studies of iron and heme absorption.

This investigation was funded by grant DK074867 from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) (JFC, PI), and grant DK109717 from NIDDK and the Office of Dietary Supplements (to JFC, PI).

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Epithelial aryl hydrocarbon receptor regulates IL-22 producing colonic group 3 innate lymphoid cells to augment microbial metabolite mediated protection in colitis
Authors: Ghosh Sweta , Vanwinkle Zachary M. , Dryden Gerald W , Kanneganti Thirumala-Devi , Haribabu Bodduluri , JALA Venkatakrishna R
Published: May 2023

The intestinal barrier dysfunction is intimately associated with inflammatory bowel diseases (IBD) as the gut barrier provides the first line of protection to host from external factors. The pathogenesis of IBD is multifactorial resulting from combinations of genetic polymorphism, environmental factors, diet, altered microbiota and the immune system. Aryl hydrocarbon receptor (AhR) is a ligand-activated basic-helix-loop-helix transcription factor which upon activation can regulate many pathophysiological functions like inflammation and gut barrier homeostasis. Recently, we identified that microbial metabolite Urolithin A (UroA) mitigated colitis in pre-clinical models through activation of AhR-dependent pathways at two distinct levels by preserving the gut barrier function and reducing systemic and acute inflammation. However, the interplay between the enhanced barrier function and reduction in inflammation and the requirement of specific cell types to mediate the UroA activities remains to be established. In the current study, we evaluated the UroA mediated cell specific requirement of AhR by using transgenic mice AhRfx-VillinCre (AhR is deleted in intestinal epithelial cells) and AhRfx-LysMCre (AhR is deleted in myeloid cells) mice. Our studies showed that UroA mediated activation of gut AhR is critical for regulation of intestinal homeostasis in dextran sodium sulphate (DSS) induced colitis. UroA also activated intestinal AhR dependent signaling to induce IL-22 production from type 3 innate lymphoid cells (ILC3). Further, our data from intestinal organoids revealed that AhR dependent-induction of IL-18 from intestinal epithelial cells is responsible for IL-22 production from immune cells. These studies revealed the novel findings that microbial metabolite mediated selective activation of AhR regulates the IL-18/IL-22-axis to maintain gut homeostasis and enhance gut barrier function to attenuate IBD pathogenesis.

Current studies are supported by NIH/NIGMS COBRE project P20-GM125504-01 and JHFEREG from University of Louisville.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Altered control of AgRP and metabolic rate during obesity via ERK and KLF4
Authors: Ritter McKenzie , Balapattabi Kirthikaa , Reho John , Claflin Kristin , Sigmund Curt , Grobe Justin
Published: May 2023

Resting metabolic rate (RMR) adaptation contributes to the maintenance of human obesity, yet mechanisms controlling RMR in lean versus obese states remain poorly defined. Leptin contributes to RMR control in part through suppression of inhibitory Agouti-related peptide (AgRP) neurotransmission in the hypothalamic arcuate nucleus (ARC). Within AgRP neurons, leptin activates the extracellular signal-regulated kinase (ERK) cascade, which is thought to interrupt Agrp transcription through interference with the Krüppel-like factor 4 (KLF4) transcription factor. Our previously published data support altered ARC ERK signaling during obesity. We therefore hypothesized a role for ERK/KLF4 signaling within AgRP neurons for the suppression of AgRP transcription and thereby stimulation of RMR in the lean state, and changes in this pathway during obesity. In the GT1-7 cell model of AgRP neurons, leptin increased the phosphorylated ERK (pERK)/ERK ratio (n=4, 1 uM, 15 min +89% p<0.05) and reduced Agrp mRNA (n=4, 1 uM, 1 hr -43.0% p<0.05); similarly, siRNA knockdown of Klf4 reduced Agrp mRNA (n=4, -21.6% p<0.05). In lean adult C57BL/6J mice, leptin increased the ARC pERK/ERK ratio (n=8, 1 ug/g ip 16.5-fold p<0.05) and stimulated RMR (n=11, 2 ug/g ip 30 min +43.8% p<0.05). Lean transgenic mice with conditional deletion of Klf4 from AgRP neurons ( Agrp-Cre x Klf4-flox) exhibited increased RMR (n=13 KO +13.48% vs controls n=22 p<0.05). These findings support the model that ERK inhibition of KLF4 within AgRP neurons mechanistically contributes to leptin-mediated control of Agrp and RMR in the lean state. Ten weeks of high fat feeding strongly increases endogenous plasma leptin in C57BL/6J mice, and this treatment increased the ARC pERK/ERK ratio (n=5 +54.4% p<0.05), yet ARC KLF4 was increased (n=6 +74.6% p<0.05). Notably, there was a lack of suppression of Agrp mRNA following prolonged high fat feeding (n=4 +1.6-fold, p=ns). Therefore, these data also support the concept that loss of ERK-mediated suppression of KLF4 within the AgRP neuron during obesity may contribute to the pathogenesis of RMR adaptation.

903246, HL134850, HL084207, DK133121, HL150340, 826132, 18EIA33890055

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Specific neuronal populations encode inflammatory responses
Authors: Hashimoto Okito , Hepler Tyler , Tynan Aisling , Tracey Kevin J , Chavan Sangeeta S
Published: May 2023

The brain maintains a homeostatic condition in the body through neuronal communication with peripheral organs. The immune system is also regulated by the nervous system with principles of reflex regulation. Neuronal pathways, including the vagus nerve-based inflammatory reflex, are physiological regulators of immune function and inflammation. However, it remains unclear whether and how the brain encodes the state of the immune system. We previously showed that the projections from the brainstem dorsal motor nucleus of the vagus nerve control inflammatory responses in the spleen. Furthermore, we found that cytokine-specific information is present in sensory neural signals within the vagus nerve. Based on these findings, we reasoned that the brain encodes and stores cytokine-specific information. In this study, we first investigated physiological parameters and serum levels of interleukin-6 (IL-6) and monocyte chemoattractant protein-1 (MCP-1) that are induced by tumor necrosis factor (TNF) and interleukin-1β (IL-1β). Increased serum levels of IL-6 and MCP-1 are observed after TNF and IL-1β administration. Interestingly, we found that IL-1β, but not TNF administration induces tachycardia. These results suggest activation of specific neural populations in the brain by TNF or IL-1β. Next, we carried out activity-dependent cell labeling in mice. We utilized the targeted-recombination-in-active-populations (TRAP2) mice crossed with a tdTomato reporter line to produce double transgenic TRAP2/tdTomato mice. Administration of TNF or IL-1β induces activation of neurons (expressing tdTomato indicative of neuronal activity) in the paraventricular nucleus (PVN), the bed nuclei of the stria terminalis (BNST) and the nucleus of the solitary tract (NTS), where vagal afferents ascending from peripheral tissues synapse on neurons. Re-exposure of mice to either TNF or IL-1β results in the labeling of additional neuronal populations in the BNST. A significant population of TNF-responsive neurons are found to be localized in the protein kinase C delta (PKCΔ)-positive subnucleus within the BNST, while IL-1β-responsive tdTomato marked neurons are predominantly located in the PKCΔ-negative region within the BNST. Together, these studies suggest that the brain encodes TNF and IL-1β-specific information in specific neuronal population.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Orexin facilitates the hypoxic ventilatory response via the activation of corticotropin-releasing hormone neurons that project to the nucleus of the solitary tract
Authors: Ben Musa Ruwaida , Cornelius-Green Jennifer , Hasser Eileen , Kline David , Cummings Kevin
Published: May 2023

The paraventricular nucleus of the hypothalamus (PVN) contributes significantly to the peripheral chemoreflex-mediated respiratory and sympathetic responses to hypoxia, in part via reciprocal interactions with nucleus of the solitary tract (nTS). Previously we showed that orexin neurons in the perifornical hypothalamus are activated by hypoxia and facilitate the hypoxic ventilatory response (HVR) in the active phase of the circadian cycle . The neural circuitry through which orexin facilitates the HVR is unknown. Orexin receptors (OxR) are expressed in the PVN, and we recently showed that OxR blockade reduced the activation of both corticotropin-releasing hormone neurons in the PVN as well as nTS neurons. In addition, hypoxia activated orexin neurons projecting to the PVN, but not those projecting to nTS. Here we further explored the hypothesis that orexin facilitates the HVR and arterial blood pressure (ABP) response to hypoxia via the activation of nTS-projecting CRH neurons, and that specific OxR1 knockdown in the PVN would reduce the HVR. To test these hypotheses, we nanoinjected fluorescent retrobeads bilaterally into the nTS to label nTS-projecting neurons. Rats were then exposed to hypoxia (2hrs at 11% O2 during the active phase) following injection of either suvorexant (OxR antagonist; 20 mg/kg i.p.; n=4), or vehicle (DMSO; n=4). Using immunohistochemistry (IHC) we then quantified the number of activated (i.e., Fos-immunoreactive; IR) nTS-projecting CRH neurons. In separate groups of rats we nanoinjected shRNA to knockdown Ox1R expression specifically in the PVN (n=8). PVN of control rats was nanoinjected with scrambled RNA (scRNA; n=3) or aCSF (n=2). Three weeks later, rats were exposed to graded hypoxia (from 21% to 10% inspired O2) over 3-5 minutes to assess the acute HVR and ABP response to different levels of hypoxia. OxR blockade reduced the number of Fos-IR, nTS-projecting CRH neurons by ~32% (drug: p<0.0001). Images confirmed successful targeting of shRNA to PVN, and OxR1 knockdown (by ~50%) was confirmed in subsets of samples by Western Blot and IHC. Ox1R knockdown specifically in the PVN had no effect on resting ventilation, but significantly reduced the HVR (main effect: p=0.02; 22% decrease in VE/VCO2 at 13% O2), due to a reduction in the respiratory frequency response to hypoxia (main effect: p=0.004; 38 breath/min decrease at 13% O2). Ox1R knockdown also decreased ABP (~5 mmHg at all O2 levels; main effect: p=0.0015), but not its response to hypoxia. These data suggest that orexin neurons facilitate the HVR via OxR1

Grants: 5R01HL098602 (EH, DK), 5R01HL136710 (KC)

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Circadian disruption via timing of food availability contributes to renal fibrogenesis in male, but not female mice
Authors: Benjamin Jazmine , Pati Paramita , Liu Xiaofen , Luong Tha , Pollock Jennifer , Pollock David
Published: May 2023

Previous work from our lab showed that restricting food to the lights-on (inactive) period for less than one week causes circadian misalignment blood pressure and kidney excretory rhythms. Since circadian disruption increases risk of cardiometabolic disease, we hypothesized that long-term mistiming of food intake would lead to kidney injury. Male and female 5–7-week-old C57BL6/J mice were placed on the following feeding schedules: ad libitum (AL; 24-h food access), inactive time restricted (iTRF; 12h food access during the lights-on period only), or active time restricted (aTRF; 12h food access during lights-off period only) for 9 weeks. There were no differences in 24-hr food or water intake between the feeding groups. Male iTRF mice demonstrated a significant increase in renal fibrosis with 19.9±1.5% in cortex and 18.3±8.0% area staining positive as compared to AL mice with 8.2±2% and 8.6±1.2% in cortex and medulla, respectively (p < 0.05, n=3/group). In contrast, iTRF in female mice did not result in any discernable increases in renal fibrosis (7.5±2.5% and 8.9±0.3% in cortex and medulla, respectively) compared to AL mice (11.9±2.1% and 8.8±0.0% in cortex and medulla, respectively, (n=3/group). Similarly, pulse wave velocity (PWV), a measure of vascular stiffness (ultrasound) was significantly elevated only in iTRF males compared to either AL or aTRF mice (iTRF 2.4±0.1m/s, ad libitum 1.80.1m/s, aTRF 1.7±0.3m/s, p<0.05, n=3-4/group). To determine whether the observed renal fibrosis and vascular stiffness may be related to blood pressure, mean arterial pressure (MAP) was measured via telemetry in iTRF and aTRF animals. Data for both sexes were similar but combined due to lack of power to test for a sex effect (7/10 female iTRF, 6/11 female aTRF). At 4 weeks of iTRF, we observed a significant interaction of 24-h MAP rhythm between genotypes that was driven by lower MAP during the dark phase of iTRF compared to aTRF mice (Repeated measures 2-way ANOVA; genotype p=0.6793, time of day p<0.0001, interaction p<0.001) Finally, quantitative magnetic resonance revealed no significant differences between groups in body composition regardless of sex, suggesting that circadian disruption by TRF does not result in caloric restriction or weight loss. Together, these data demonstrate that circadian disruption by restricting food access results in significant fibrosis in both kidney and vascular tissues preferentially in male, but not female mice. These changes appear to be independent of changes in blood pressure.

PRIME T32 DK116672 (J. Benjamin), AHA Career Development Grant (P. Pati), P01HL136267 (D. Pollock, J. Pollock)

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
FoxS1 is a Novel Mediator of Hepatic Fibrosis Through Transcriptional Control of the Extracellular Matrix
Authors: Lee Wang-Hsin , Bates Evelyn , Martinez Genesee , Kipp Zachary , Xu Mei , Hinds, Jr Terry
Published: May 2023

The increasing rates of obesity have led to elevated rates of non-alcoholic fatty liver diseases (NAFLD), which can progress to non-alcoholic steatohepatitis (NASH) and liver fibrosis, liver cirrhosis, and possibly cancer. The hepatic stellate cells (HSCs) have been considered major players in fibrogenesis in liver damage that leads to irreversible scarring. The activation of HSCs occurs as a liver injury signal via transforming growth factor β (TGF-β), which then causes the cells to proliferate and shed their extracellular matrixes. FoxS1, a barely studied transcription factor, was recently found to be increased by tumor growth factor-β (TGF-β) signaling. However, the role of FoxS1 in liver fibrosis has never been demonstrated. Our Real-Time PCR data showed that FoxS1 mRNA was increased in human cirrhotic livers that have significantly higher TGF-β, as well as in a murine model of liver fibrosis. Therefore, we hypothesize that the TGF-β-induction of FoxS1 is an essential process of HSCs activation that leads to hepatic fibrosis and scarring. To test this hypothesis, we created a FoxS1 CRISPR knockout (FoxS1 KO) and scrambled control LX2 cell lines, which are the standard human HSCs used for studying hepatic fibrosis. Then, we performed TGF-β treatments and extracted RNA for RNA sequencing and bioinformatic analysis to determine genes and pathways that are altered by the loss of the FoxS1 transcription factor. Our data demonstrate that FoxS1 regulates genes involved in collagen-containing extracellular matrix pathways, indicating that suppression of FoxS1 might prevent liver scarring. However, more work is needed in animal models to make this determination. In conclusion, these data demonstrate that FoxS1 induces liver fibrosis and plays a critical role in TGF-β-induced human HSC-extracellular matrix production that occurs during hepatic scarring. Based on the findings, FoxS1 may serve as a new therapeutic target for liver fibrosis.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Collagen peptide reduces post-MI inflammatory response
Authors: Olabiyi Ayodeji , Cakir Sirin , de Castro Bras Lisandra
Published: May 2023

Progressive adverse remodeling of the left ventricle (LV) after myocardial infarction (MI) includes persistent inflammation and degradation of the extracellular matrix that can lead to the dilation of LV and eventually congestive heart failure. Previously, we reported a collagen derived peptide – p1159 – to reduce LV dilation and adverse LV remodeling post-MI. This study evaluates the effect of p1159 in the post-MI acute inflammatory response. We hypothesize p1159 reduces LV dilation by mitigating the inflammatory response. Two groups of mice (C57BI/9; n=4/group) consisting of saline (vehicle) and p1159 treatments, same sex (female, 3- 6 months old), were used in this study. We performed baseline echocardiography followed by surgery to induce a permanent occlusion MI model. Three hours post-MI, mice received a randomized osmotic mini-pump to continuously deliver p1159 (14μg/day/kg body weight) or vehicle (saline, 0.9%). The LV was harvested on day three (D3) after a final echocardiographic assessment. Infarct size measurements (2,3,5- triphenyl tetrazolium chloride ‘TTC’ staining and strain analysis) were performed followed by gene array against 84 inflammatory markers using only the infarcted tissues. Infarct sizes were similar between groups, indicating same level of initial injury. Compared to vehicle controls, p1159 treatment markedly reduced levels of pro-inflammatory chemokines that associate with lymphocyte and leukocyte infiltration. Specifically, levels of both CCL22, a Th2-/Treg type chemokine known to increase in ischemic heart disease, and CCL24, which has been implicated in activation of fibrogenic pathways, were significantly reduced by p1159. Our data supports that p1159 treatment mitigates the inflammatory response post-MI, which in turn results in reduced adverse LV remodeling.

This work was supported by the NIH/NHLBI (grant HL152297).

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
A Rejuvenation Signature in Skeletal Muscle That Is Mediated By Late-Life Exercise
Authors: Jones Ronald , Dimet-Wiley Andrea , Haghani Amin , Morena da Silva Francielly , Brightwell Camille , Lim Seongkyun , Khadgi Sabin , Wen Yuan , Dungan Cory , Brooke Robert , Greene Nicholas , Peterson Charlotte , McCarthy John , Horvath Steve , Watowich Stanley , Fry Christopher , Murach Kevin
Published: May 2023

The objectives of this study were to measure to what extent exercise stimulates partial molecular reprogramming in skeletal muscle. We hypothesized that exercise training, beyond its known functional improvements in aged tissues, could recapitulate some of the same effects that are seen with in vivo partial reprogramming by Yamanaka factors. Using transcriptome profiling from 1) a skeletal muscle-specific in vivo Oct3/4, Klf4, Sox2, and Myc (OKSM) reprogramming-factor expression murine model, 2) an in vivo inducible muscle-specific Myc induction murine model, 3) a translatable high-volume hypertrophic exercise training approach in aged mice, and 4) human exercise muscle biopsies, we collectively defined exercise-induced genes common to partial reprogramming. Late-life exercise training lowered murine DNA methylation age according to several contemporary muscle-specific clocks. A comparison of the murine soleus transcriptome after late-life exercise training to the soleus transcriptome after OKSM induction revealed an overlapping signature. Within this signature, downregulation of specific mitochondrial and muscle-enriched genes was conserved in skeletal muscle of long-term exercise-trained humans; among these was muscle-specific Abra/Stars. Myc is the OKSM factor most induced by exercise in muscle and was elevated following exercise training in aged mice. A pulse of MYC rewired the global soleus muscle methylome, and the transcriptome after a MYC pulse partially recapitulated OKSM induction. A common signature also emerged in the murine MYC-controlled and exercise adaptation transcriptomes, including lower muscle-specific Melusin and reactive oxygen species-associated Romo1. With Myc, OKSM, and exercise training in mice as well habitual exercise in humans, the complex I accessory subunit Ndufb11 was lower; low Ndufb11 is linked to longevity in rodents. Our data collectively suggest: 1) a biological age-mitigating effect on the epigenetic landscape by late-life exercise-training in murine skeletal muscle, 2) a common gene expression signature of partial reprogramming by OKSM and exercise training in muscle of humans and aged mice, and 3) that Myc is an exercise-responsive factor that contributes to a rewired molecular profile at the transcriptome and methylome levels.

National Institutes of Health: Kevin A. Murach, AG063994; American Federation for Aging Research (AFAR): Kevin A. Murach, Junior Investigator Grant

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Role of PPAR gamma in Acute Renal Failure
Authors: Yousefipour Zivar , Newaz Mohammad
Published: May 2023

Objective: Acute Renal failure (ARF) is a common sequel to chronic diseases such as hypertension and Diabetes Mellitus. Understanding the mechanism involved in damaging the glomerular membrane at the molecular level is of significant importance since this will allow us to prevent molecular changes before they attain a level of irreversibility.Oxidative stress and nitric oxide (NO) play a significant role in the maintenance of renal tubular and glomerular function in health and illness. Enzymes responsible for either ROS generation or NO production are controlled by transcription factors such as peroxisome proliferator activated receptor gamma (PPARγ). Here, we hypothesized that oxidative stress during chronic disease process reduced PPARγ gene expression and therefore, NAD(P)H oxidase NO production. Design and method: We used a glycerol model of ARF in male Sprague-Dawly rats, divided in control and treated groups. ARF was induced using the standard method involving administration of 50% glycerol (v/v, 8 mL/kg, i.m). After 21 days of study period, the required amount of glycerol was administered as a deep intramuscular injection equally distributed to both hind legs. Rats were deprived of food and water for 24 hours after glycerol administration. After injecting glycerol, rats were placed in metabolic cages, and 24 hr urine was collected. Blood was collected via cardiac puncture under pentobarbital anesthesia (Na pentobarbital 50 mg/kg; i.p). Kidneys were processed for isolation of renal microvessels and subsequent biochemical and molecular biology analysis. Results: Our results indicated reduced PPARγ mRNA and protein expression and activity in ARF. Addition of PPARg inducer, Ciglitazone, increased PPARγ mRNA and protein expression and activity in ARF. Ciglitazone improved renal vascular reactivity that was exaggerated in ARF. We observed ~100% increase in 8-isoprostane level in the plasma of ARF rats compared control. Ciglitazone abolished the increase in free-radical generation significantly. Conclusion: Based on our data we are concluding that reduced PPARg has a definitive role in the kidney function.

This work was supported by an Innovation grant from Texas Southern University.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Preliminary Characterization of Facial and Oral Microbiomes of Three Bat Species Commonly Occurring in Northwest Kansas
Authors: Miller Sarah , Kobayashi Yass
Published: May 2023

Various bat species are at risk due to White-Nose Syndrome, a disease rapidly spreading throughout the United States. Metagenomic research on the microbiome of bats’ mouths and noses may provide helpful information to characterize how bats’ microbiomes interact with White-Nose Syndrome so that this disease may be mitigated. However, minimal research has been conducted in characterizing bats’ oral and facial microbial populations. To address this issue, we analyzed the oral and facial microbiomes of bat species commonly occurring in Northwestern Kansas. Oral and facial swabs were taken from Tricolor, Big Brown, and Evening bat (n=1 per species). Bacterial DNA was isolated from swabs, and the V3/V4 region of the 16s DNA was amplified using polymerase chain reactions (PCR). The PCR products were purified and sequenced. Sequencing data was then analyzed using Galaxy bioinformatics software. Results showed that the majority of bacteria present in facial swabs was Alteromonas, reflecting the high mineral content in the water source that bats use. Oral bacterial population profiles of Tricolor and Big Brown bats were more diverse than their respective facial samples. In contrast, oral and facial swabs from the Evening bat had similar bacterial population profiles. Our preliminary study showed that the oral samples appeared more diverse in bacterial populations than in facial. Therefore, our future studies should investigate the difference between oral and facial bacteria population profiles in more detail by investigating a larger sample and increasing bat species diversity. Further research should also include the seasonal effects on bacterial populations.

The College of St. Scholastica Summer Undergraduate Research Fellowship

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Contribution of cervical sympathetic nerve activity during swallowing following CIH exposure
Authors: Karlen-Amarante Marlusa , Huff Alyssa , Oliveira Luiz , Ramirez Jan-Marino
Published: May 2023

Swallowing is a vital behavior that is coordinated with breathing involving rhythmogenic networks in the medulla, the preBötzinger complex (PreBötC) and postinspiratory complex (PiCo). These networks are critical for generating inspiratory and postinspiratory activity, respectively. Both areas also interact with neurons involved in autonomic control, which contributes to increased sympathetic drive after chronic intermittent hypoxia exposure (CIH) exposure.Prior studies have demonstrated that CIH, an experimental model of obstructive sleep apnea, has been associated with dysphagia. However, the contribution of the sympathetic activity to swallow function is unknown in both healthy and diseased models. In this study we investigated the cervical sympathetic response to water swallow stimulation as well as optogenetic stimulation of the brainstem in an in vivo mouse preparation under control and CIH conditions for 21 days (5% O2 – 80 bouts/day). Recordings of diaphragm (DIA), submental and laryngeal muscles complex, hypoglossal (HN), vagus (cVN), and cervical sympathetic nerves (cSN) were performed in spontaneously breathing, anaesthetized (Urethane 1.5mg/kg) adult mice in baseline conditions and during swallow stimulation by injecting 0.1cc of water into the mouth. We found that baseline cSN is enhanced after CIH exposure due to a blunted respiratory-sympathetic coupling. During swallow stimulation, cSN activity was increased in both groups, which was further increased in the CIH group, suggesting swallow triggers an excitatory vasomotor sympathetic pathway. In order to understand the mechanistic underpinning of these findings, we use optogenetic stimulation of PreBötC and PiCo neurons to explore the effects on sympathetic activity modulation during swallow-breathing coordination.

NIH Grants: P01 HL090554, R01 HL126523, R01 HL144801, R01 HL151389 and FY22 24050162.

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
No impact of biological sex on nitric oxide contribution to cutaneous vascular response to 39ºC local heating
Authors: Williams Auni , Dillon Gabrielle , Wolf S. , Kenney W , Alexander Lacy
Published: May 2023

Purpose: The contribution of endothelial nitric oxide (NO) to vasodilation (%NO contribution) is a significant indicator of risk of cardiovascular disease development. Local skin heating to either 42 ºC or 39 ºC is used to determine mechanisms of vasodilation in health and disease, specifically to investigate %NO contribution. Women have lower %NO contribution in the cutaneous vasculature than men in the early follicular phase of the menstrual cycle, when the circulating vasoactive reproductive hormones are at their lowest concentration. However, this phase represents only a brief portion of the menstrual cycle. We aimed to determine the overall impact of biological sex on %NO contribution to cutaneous vasodilation utilizing a 39ºC local heating protocol, which better isolates the endothelial NO-synthase pathway. We tested women randomly during any phase of the menstrual cycle. We hypothesized that women would demonstrate greater NO-dependent cutaneous vasodilation than men in response to 39ºC local heating. Methods: Data are represented as mean(SD). An intradermal microdialysis fiber was placed in the ventral forearms of 12 men and 13 women [24.2(4.6) years]. Local heaters and laser-Doppler flowmetry probes were used to measure red blood cell flux (perfusion units, PU). Cutaneous vascular conductance (CVC) was calculated as laser-Doppler PU/mean arterial pressure. A standard 39ºC local heating protocol was conducted wherein PU was continuously collected at rest (10 minutes), then the local temperature was increased to 39ºC. After PU reached a steady plateau (~40 minutes), the NO synthase inhibitor 15 mM NG-nitro-L-arginine methyl ester (L-NAME) was perfused. Maximal vasodilation was induced by heating to 43ºC and perfusing 28 mM sodium nitroprusside and normalized to %CVCmax. %NO contribution was calculated as the absolute percentage difference between %CVCmax of 39ºC plateau and %CVCmax of L-NAME steady-state. We compared both CVC and %CVCmax between groups with two-way ANOVA and the %NO contribution with unpaired t-tests. Results: The %NO contribution was not different between sexes [men 48(23)%, women 39(17)%; P = 0.26]. There was no effect of sex on either absolute CVC [men 0.717(0.29) PU, women 0.73(0.48) PU at 39ºC phase] or %CVCmax [men 69(31)%, women 54(20)% at 39ºC phase] at any stage of the 39ºC local heating protocol (main effects P ≥ 0.08). Conclusion: These data indicate there is no impact of biological sex on the vasodilatory response of the cutaneous vasculature to 39ºC local heating in young healthy adults when women are tested at random across the menstrual cycle.

Funding: National Institutes of Health Grant T-32-5T32AG049676

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
Associations between Aortic Stiffness, Cerebral Artery Resistance and White Matter Integrity in Women with a History of Preeclampsia
Authors: Nuckols Virginia , Magnotta Vincent , Hoth Karin , Santillan Mark , Pierce Gary
Published: May 2023

Purpose: Preeclampsia is a pregnancy complication characterized by new-onset hypertension and systemic organ dysfunction. Women with a history of preeclampsia (hxPE) have a greater cerebral white matter ischemic damage burden and a three-fold elevated risk of vascular dementia later in life compared with healthy pregnancy independent of traditional cardiovascular risk factors. Aortic stiffness promotes the transmission of deleterious pulsatile pressure to the distal cerebral circulation, resulting in increased cerebrovascular resistance (CVR) that contributes to compromised brain blood flow and structure. We hypothesized that young women with hxPE would have greater aortic stiffness and CVR compared to healthy pregnancy, and CVR would be related to lower cerebral white matter microstructural integrity (WMI). Methods: Women with hxPE (N=10) were matched with healthy pregnancy controls (N=11) by age (28-42 years), educational attainment, body mass index, and postpartum duration (1-5 years). Aortic stiffness was quantified as carotid-femoral pulse wave velocity (CFPWV). 4D flow and diffusion tensor magnetic resonance images were acquired to evaluate internal carotid and middle cerebral artery (MCA) blood flow velocity and WMI (fractional anisotropy), respectively (3T MRI, GE). CVR index was calculated as the ratio of central mean arterial pressure to regional flow velocity. Results: Women with hxPE tended to exhibit higher CFPWV compared with controls (6.3±0.8 vs 5.6±0.7 m/s, P=0.09 adjusted for mean arterial pressure). CVR did not differ at the internal carotid artery (2.2±0.4 vs 2.0±0.3 mmHg s cm-1, P=0.30) but was higher at the MCA among women with hxPE (2.4±0.3 vs 2.1±0.4 mmHg s cm-1, P=0.08). In the entire group, CFPWV was associated with greater CVR at the internal carotid (r=0.41, P=0.07) and MCA (r=0.48, P=0.03). Although WMI did not differ between groups, greater MCA CVR was related to lower WMI overall (r=-0.45, P=0.049) and in select white matter tracts (corpus callosum genu, r=-0.53, P=0.02; cingulum hippocampus, r=-0.43, P=0.06; superior frontooccipital fasciculus, r=-0.46, P=0.04). Conclusions: Women with hxPE had elevated aortic stiffness that was associated with greater CVR. Greater CVR was related to lower WMI in subcortical watershed regions susceptible to reduced perfusion. These findings indicate that aortic stiffness may contribute to early declines in WMI via CVR in women with hxPE.

Supported by AHA Transformational Project Award (969732) to GLP and NIH grant 1S10OD025025-01 to VM

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.
A summer physiology research program directed toward underrepresented students, UPRIME (Undergraduate Physiology Research In Medicine and Education), fosters and engages students into physiology research
Authors: Wu Steven , Anderson Lisa , Metzger Joseph , Barnett Vincent
Published: May 2023

The Department of Integrative Biology and Physiology at the University of Minnesota is committed to supporting outstanding physiology majors interested in research and gaining research experience. We have created a program, UPRIME (Undergraduate Physiology Research In Medicine and Education), which has: 1) Foster young and aspiring undergraduates interested in physiology and biomedical research, and 2) Create unfettered opportunities for students that are both underrepresented in research and have strong interests in physiology research and education. UPRIME (Undergraduate Physiology Research In Medicine and Education) is a 10-week summer program hosted by the Department of Integrative Biology and Physiology at the University of Minnesota and sponsored by an American Heart Association award. Students (“UPRIME Scholars”) were either juniors or seniors that had just started working in physiology labs. They were selected on the basis of: 1) Scientific merit of their projects, 2) If they were underrepresented in research (as defined by NIH and/or especially in Minnesota), and 3) If they were from low socio-economic status. To meet our goals, UPRIME Scholars met once a week to discuss research and scientific methods. As the UPRIME Scholars were relatively inexperienced in research, we designed our meetings to be safe and open spaces for encouraging discussion, especially about their research projects. Discussion topics included techniques (e.g. qPCR, histology, and cell culture), experimental design (e.g. animal models, use of controls), and developing a hypothesis. In addition, we had UPRIME Scholars attend weekly “Graduate Student Colloquia” where our graduate students give formal presentations and chalk talks about their research. Here, UPRIME Scholars were tasked to identify and discuss the hypotheses tested, animal or experimental models used, and interpretation of results. In our first two years, UPRIME Scholars reported very positive experiences in their summer research and in the usefulness of the weekly meetings. They were able to better understand why they were doing their projects, how their projects were an important part of their mentor’s research, and how to troubleshoot the techniques they used. Taken together, the UPRIME program has been successful in the fostering of undergraduates in physiology research. The UPRIME program serves as our basis for future programs for undergraduates interested in research.

American Heart Association

This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.