bluuebunny/crossref_metadata_2025 huggingface dataset:
Viscoelastic Model for Microglial Oscillations
Authors: Park Eun Young , Cho Youngbin , Ko Ung Hyun , Park Jin‐Sung , Shin Jennifer
Published: November 2023

Introduction

Motility is a critical physiological process in wound healing, cancer metastasis, and immune responses. It involves complex orchestration of cytoskeletal proteins and adhesion molecules to generate protrusive forces, contractility, and directionality. Motile traits often represent the functional or physiological state of the cells. For example, some types of monocytes feature the patrolling mode and transform into directional migratory mode upon the inflammatory conditions. In this study, we present microglia, a type of immune cells in the central nervous system, which exhibit several distinct morphological phenotypes, namely ramified, withdrawal, transitional, motile, and locomotory, depending on its physiological state. Especially the microglial cells in the motile state show striking oscillatory behavior in the absence of external cues, which can be induced to transform into persistent migration upon stimulation. This rapid and reversible transformation was found to involve dynamic rearrangements of cytoskeletal proteins and redistribution of forces, evidenced by traction force microscopy (TFM). To unravel the complexity in the multiple involvement of cytoskeletal proteins in force generation, here we focus on the oscillatory behavior of the microglia and propose a simple lumped‐parameter viscoelastic model with mass, spring and damper components each of which represents elastic contractility and viscous adhesive drag induced by cytoskeletons and associated proteins. Through this study, we aim to investigate the roles of the cytoskeletal proteins and adhesions in each of the elements in the model.

Methods

Microglia were extracted from the cortex in the brain of rats and seeded in a fibronectin coated microchannel (3×0.242×14 mm, W×H×L) for real time imaging. To measure the cellular physical forces, we performed TFM using a soft PA gel. For the simulations of models and analysis, we used MATLAB.

Results and Discussions

We studied the roles of the cytoskeletal proteins and adhesions by chemically inhibiting them. Moreover, we employed TFM to visualize the redistribution of stresses during oscillation. Based on the obtained results of temporal and spatial changes in cellular positions and associated forces, we found the mechanical correlations between cellular components and viscoelastic elements by the simulation. We propose that the oscillatory phenotypes of microglia are regulated by the microtubules in terms of maintenance of morphologies, and by the actin filaments and myosin II in terms of contractility.

Support or Funding Information

This work was supported by the National Research Foundation of Korea Grant funded by the Korean Government (NRF‐2013S1A2A2035518)
AD‐20 Inhibits Prostate Cancer Cell Migration and Tumor Metastasis by Suppressing NRP1 Expression
Authors: Li Xin
Published: November 2023

Metastasis, a complex, multi‐step process, is the leading cause of death in patients diagnosed with cancer. Interaction between tumor cells and extracellular matrix (ECM) plays a critical role in the regulation of metastasis. Natural products have been a source of novel drugs for decades owing to their versatile biological activities and comparatively low toxicity. In our study we screened a natural product database for anti‐migration effect on prostate cancer PC‐3 cell line and eventually acquired a natural product AD‐20 exhibiting inhibitory effects in both in vitro and in vivo intravenous injection xenograft model.

To understand how AD‐20 suppresses cell migration and tumor metastasis, LC‐MS/MS analysis was employed to identify significant different proteins (SDP) in AD‐20 treated PC‐3 cells. Then a SDP‐based protein‐protein interaction network was generated and integrated into Gene ontology (GO) enrichment network containing three cell movement associated GO terms. Consequently, two SDPs, neuropilin 1 (NRP1) and fibronectin (FN), were annotated with all three cell movement associated GO terms, suggesting that NRP1 and FN may be the key proteins accounting for the functions of AD‐20.

As a co‐receptor for VEGF and several other growth factors (GFs), NRP1 is largely involved in angiogenesis and tumor progression. Besides functions relevant to GFs, NRP1 also regulates the interaction between cells and ECM by interacting with active integrin α5β1 and facilitating its turnover. FN is a high molecular weight ECM protein, whose assembly is largely mediated by the function of integrin α5β1. By Western Blot we confirmed that AD‐20 inhibits expression of both NRP1 and FN in PC‐3 cells, consistent with our results in proteomic study. Cell motility is attenuated in NRP1−/− PC‐3 cells, while the effect of AD‐20 is milder in NRP1−/− cells than in wild type cells. These results indicate that AD‐20 functions on cell migration partly, if not solely, through impairing NRP1 expression. Besides cell motility, cell adhesion to FN is also compromised in AD‐20 treated wild type cells and NRP1−/− PC‐3 cells. Further, in fibroblast cell model AD‐20 treatment also suppresses NRP1 and FN expression and FN filaments assembly. The results in both cell types suggest that AD‐20 plays a comprehensive role in modulating the interaction between cancer cells and ECM.

In summary, we found that AD‐20 inhibits prostate cancer PC‐3 cell migration and tumor metastasis by inhibiting NRP1 expression. Besides, AD‐20 may influence the interaction between cells and ECM by impacting NRP1 function, which is critical in metastasis process. Concerning the potential of NRP1 as a target for anti‐cancer drug development and the clinical trials of NRP1 monoclonal antibody, AD‐20 may have a bright prospect to be developed into a chemical based anti‐cancer drug targeting NRP1 and relevant pathways.

Support or Funding Information

National Natural Science Foundation of China
The Role of Taurine in the Anoxia‐Tolerant Western Painted Turtle Brain
Authors: Miles Ashley , Buck Leslie
Published: November 2023

Unlike the anoxia‐intolerant mammalian brain, which undergoes hyperexcitability and neuronal death in response to anoxia, the western painted turtle (Chrysemys picta) can survive extended periods of anoxia without significant neuronal damage. This is in part accomplished by a large increase in the concentration of the inhibitory neurotransmitter gamma‐aminobutyric acid (GABA) resulting in suppression of spontaneous electrical activity (i.e. spike arrest) through a mechanism known as shunting inhibition. In addition to GABA, levels of the amino acid taurine also increase in the anoxic turtle brain, but its function is not known. It is speculated that taurine can function like a neurotransmitter by acting through GABA receptors. Given the important role of GABA in the anoxic turtle brain, we wanted to investigate the role of taurine by determing whether turtle cortical neurons are responsive to taurine and what receptor(s) taurine may be acting through. Using the whole cell patch clamp technique, we measured the electophysiological properties of neurons in response to taurine. We found that 10mM taurine caused the membrane potential of cortical neurons to depolarize approximately 8mV, similar to the effects of GABA and anoxia. Additionally taurine increased the whole cell conductance (Gw) >2‐fold. These effects were reduced but not completely abolished when strychnine, a glycine receptor antagonist, and/or gabazine, a GABAA receptor antagonist were applied. Together these results suggest that taurine can act through both glycine and GABA receptors to effect turtle cortical neurons and therefore may also play a signaling role during anoxia in the turtle cortex.

Support or Funding Information

This research is supported by the Ontario Graduate Scholarship (OGS) and Canadian Graduate Scholarship‐Master's (CGS‐M NSERC) awarded to Ashley Miles and the Discovery Accelerator Supplements Grant awarded to Les Buck.
Dysfunction of Astrocytes in the Nucleus Tractus Solitarii Leads to Cardiorespiratory Compromise
Authors: Talman William T. , Lin Li‐Hsien , Jones Susan , Dragon Deidre Nitschke , Wu Yuanming , Richerson George B.
Published: November 2023

We have previously shown that saporin (SAP) microinjected into the nucleus tractus solitarii (NTS) causes loss of astrocytes while producing no immunohistochemical evidence of damage to NTS neurons. Loss of NTS astrocytes leads to loss of cardiovascular reflex control and, in some animals, sudden death as a result of asystole. Knowing that respiratory dysfunction and apnea may lead to asystole, we hypothesized that astrocytic dysfunction compromises respiratory control and may lead to apnea and sudden death. We sought to test that hypothesis in rats treated with bilateral NTS injections of the ribosomal toxin SAP, a chronic model of astrocytic loss, or fluorocitrate, which produces an acute model of astrocytic dysfunction. We first sought to determine if the loss of astrocytes due to SAP was due to necrosis or apoptosis by injection of SAP unilaterally into the NTS. We found loss of immunoreactivity for glial fibrillary acidic protein (GFAP), a marker of astrocytes, two hours, six hours, one day and seven days after SAP injection and increased immunoreactivity for the necrosis marker, receptor interacting protein (RIP), 6 hours and one day after SAP injection. In contrast, SAP treatment did not lead to apoptosis as documented by absence of positive cells in TUNEL reaction in the NTS. Injection of SAP into the NTS of neonatal rats (P13) led to loss of GFAP immunoreactivity seven days later as it also does in the adult rat brain. Therefore, in brain slices from P20–23 rats that had been treated unilaterally with SAP seven days previously, we performed patch clamp recording from neurons in the NTS and found that their intrinsic electrophysiological properties were unremarkable compared to neurons on the control side. In adult animals we monitored breathing chronically in a plethysmographic chamber after bilateral NTS microinjection of SAP. Seven days after injection, awake, treated rats, in contrast to control rats, began to manifest slow, irregular breathing patterns during eupneic breathing. During acute studies of astrocytic dysfunction, rats were anesthetized with isoflurane and respiration was monitored by intercostal electromyographic recording concurrent with recording arterial blood pressure and heart rate. Bilateral injections of fluorocitrate were made into NTS at 15 minute intervals for 2 hours. Fluorocitrate treated rats, but not rats treated with vehicle or PBS, developed slowed breathing followed by periodic apnea. These studies suggest that SAP causes necrosis of astrocytes and spares neuronal function. Either astrocytic necrosis or transient astrocytic dysfunction in the NTS interferes with normal cardiorespiratory regulation and leads to hypopnea and apnea that may contribute to death.

Support or Funding Information

NIH R01HL088090 and VA Merit Review
Comparing the Location of Medullary Dorsal Horn Neuronal Activation during Voluntary Diving with the Central Terminations of Nerves that Innervate the Nose and External Nares
Authors: DelPrete Benjamin , Lahrman Kenneth , Warren Erik , DiNovo Karyn , McCulloch Paul
Published: November 2023

When animals dive underwater there is a reflex initiation of the diving response. This cardiorespiratory response includes parasympathetically‐mediated bradycardia, a sympathetically‐mediated increase in total peripheral resistance, and apnea. The afferent limb of this reflex includes the medullary dorsal horn (MDH), specifically the superficial laminae of the MDH between the pyramidal decussation caudally and obex rostrally. This is also the location of the central terminations of trigeminal nerves that innervate the nose and external nares, such as the anterior ethmoidal nerve (AEN) and nasal branch of the infraorbital nerve (ION). The objective of this research was to compare the pattern of neuronal activation of secondary neurons activated by voluntary diving, as determined by neuronal Fos production, with the central terminations of the AEN and ION, as determined by the transganglionic tracer Wheat Germ Agglutinin (WGA). Sprague‐Dawley rats (N=12) were trained to voluntarily dive underwater through a 5 m maze. Six rats had 24 dive trials over 2 hours to activate brainstem neurons to produce Fos, while the remaining rats were cage controls. Other rats had 1 μl of 100% WGA injected into the AEN (N=4) or ION (N=9), 4 μl of 100% WGA injected under the skin of the hairy (N=6) or glabrous (N=3) nose, or 60 μl of 50% WGA injected into the nasal passages (N=4) or nasal vestibule (N=3). The location of Fos positive neurons within the MDH of the diving rats was then compared to the MDH labeling pattern from the WGA injected rats. Results indicate that WGA central termination sites showed varying degrees of overlap with the location of Fos‐positive neurons, depending upon which nerve or nasal area received the WGA injection. We conclude that the ION, in addition to the AEN, could possibly be an anatomical pathway that provides the afferent information necessary to initiate the mammalian diving response.

Support or Funding Information

Supported by CCOM Suarez Summer Research Fellowships (BDP and KAL), CHS MBS program (EAW), and MWU Intramural funding (PFM).
Subfornical Organ Neurons Integrate Cholecystokinin and Angiotensin II Signals
Authors: Cancelliere Nicole Mariantonia , Ferguson Alastair V
Published: November 2023

The subfornical organ (SFO) is a sensory circumventricular organ implicated in the regulation of energy and fluid balance. SFO neurons have been shown to express receptors for and respond to both cholecystokinin (CCK) and angiotensin II (ANG)‐hormones traditionally classified as energy and fluid balance signals, respectively. The purpose of this study was to investigate whether neurons that respond to CCK could also respond to ANG. SFO neurons were micro‐dissected from Sprague‐Dawley rats (21–28 day), dissociated into individual neurons, and incubated at 5mM glucose. Using the perforated patch clamp electrophysiology technique, effects on membrane potential were assessed after isolated SFO neurons were bath applied with CCK‐8S [10nM] followed by ANG II [10nM], allowing for successful washout of the hormone and recovery of the neuron (if responsive) between applications. Our results show that 25% of SFO neurons tested respond to both CCK and ANG directly, causing a depolarization of the membrane potential in response to bath application of both peptides (CCK= + 6.5 mV ± 1.7 mV; ANG= + 7.0 mV ± 1.7 mV; n=2/8), and 38% of neurons tested did not respond to either CCK or ANG (CCK= + 0.2 mV ± 1.4 mV; ANG= + 0.04 mV ± 0.03 mV; n=3/8). A separate population of neurons (38%) did not respond to CCK, and depolarized after ANG application (CCK= − 0.4 mV ± 0.5 mV; ANG= + 9.2 mV ± 4.5 mV; n=3/8). These preliminary data demonstrate that there is a subpopulation of SFO neurons which respond to both CCK and ANG, suggesting that single SFO neurons are able to integrate both of these traditionally classified energy and fluid balance signals.

Support or Funding Information

This work was supported by the Canadian Institutes of Health Research (CIHR)
Cholinergic Stimulation of Immune Cells with Nicotine Induces Renal Inflammation and Pre‐mature Development of Hypertension in Young SHR
Authors: Harwani Sailesh , Chapleau Mark , Abboud Francois
Published: November 2023

We have shown that nicotinic cholinergic stimulation of immune cells in vitro and in vivo exaggerates pro‐inflammatory innate immune responses and increases proliferation of a CD161a+/CD68+ macrophage population in isolated bone marrow cells and splenocytes in young pre‐hypertensive Spontaneously Hypertensive Rat (SHR). In vivo administration of nicotine also led to renal infiltration of macrophages within 24 hours, without any increase in arterial pressure and independent of renal sympathetic innervation. We also found that 2 week subcutaneous infusion of nicotine not only leads to continued CD161a+/CD68+ macrophage infiltration, but also the development of premature hypertension in young SHR. We hypothesized 1) that the nicotine induced CD161a+/CD68+ macrophage infiltration is caused by increased renal expression of Vascular Cell Adhesion Molecule‐1 (VCAM‐1) and 2) this renal macrophage infiltration results in renal damage/toxicity. Nicotine (15mg/kg/day) was infused subcutaneously for 2 weeks. Systolic blood pressures (SBP) were measured twice weekly by tail cuff and urine, serum, and kidney tissue were collected at the end of nicotine infusion. Tissues and fluid were analyzed by luminex assay. Renal lysates were also analyzed by Western blot for the presence of VCAM‐1. Nicotine infusion led to the pre‐mature development of hypertension in SHR (153.2 ± 3 mmHg vs 138.6 ± 3 mmHg in saline infused SHR, respectively, n=10, p <0.001). There was no significant increase in SBP in control Wistar Kyoto (WKY) rats infused with nicotine, compared to saline. There was a greater infiltration of the kidney with CD161a+/CD68+ macrophages with nicotine infusion (16±2 cells per 400× field), compared to saline infusion (9±1 cells per 400× field) (n=6, p<0.001). In contrast, there was no significant renal macrophage infiltration in nicotine infused WKY, compared to saline (1±1 cells vs 1±1 cells per 400× field) (n=6, p>0.05). CD161a+/CD68+ renal macrophage infiltration in the young SHR was not associated with an increase in VCAM‐1 expression. However, nicotine induced renal CD161a+/CD68+ macrophage infiltration was associated with renal damage/toxicity, as measured by an increase in urinary Interleukin −18 (IL‐18) (283±42 pg/mL vs 101±10 pg/mL, n=4, p<0.001) and Monocyte Chemoattracatant Protein‐1 (MCP‐1) (241±22 pg/mL vs 145±23 pg/mL, n=4, p<0.05). We conclude that cholinergic stimulation with nicotine leads to renal infiltration with a CD161a+/CD68+ macrophage population that is not explained by renal expression of VCAM‐1, but is associated with renal damage, as well as the pre‐mature development of hypertension. Thus, renal damage from infiltration of this CD161a+/CD68+ macrophage population is one of the mechanisms involved in nicotine induced hypertension in the young pre‐hypertensive SHR.

Support or Funding Information

NIH K08 HL11958NIH PPG HL014388
FEMALE RATS SHOW POST‐TRAUMATIC STRESS‐LIKE BEHAVIOR AND TNFα‐POSITIVE CARDIAC MAST CELL DEGRANULATION UPON EXPOSURE TO FEARED CUES 8 WEEKS AFTER CORONARY ISCHEMIA/REPERFUSION
Authors: Scrogin Karie , Binda Nkongho , Robbins Elizabeth , Lee Sharmaine , Vantrease Jaime , Samarel Allen
Published: November 2023

Pre‐ and perimenopausal women have a higher mortality risk following myocardial infarction (MI) than men of the same age. Risk factors such as obesity, diabetes, smoking, and characteristics or treatment of MI do not fully account for this increased risk. However, MI can induce post‐traumatic stress disorder (PTSD), and post‐MI PTSD increases cardiovascular morbidity. Younger age is a risk factor for MI‐induced PTSD, and women who develop PTSD after MI have more severe symptoms. It is not clear how MI‐induced PTSD contributes to increased morbidity. However, stress is known to activate cardiac mast cells which can degranulated and release pro‐inflammatory cytokines. Here, we investigated effects of MI, sex and conditioned fear on cardiac mast cell degranulation in a rat model of coronary ischemia/reperfusion (I/R). Male and cycling female rats (in pro‐estrus) were exposed to delay fear conditioning (FC): 6 trials of tones (20 sec., 5 kHz, 90 dbl) terminated with footshock (0.5 sec, 0.3 mA), or pseudo conditioning (PC): 6 unpaired tones and footshocks. One week later, rats were randomized to coronary ischemia (45 min) and reperfusion, or sham surgery. Eight weeks later, pro‐estrus female and male FC, but not PC rats, showed initial freezing responses to presentations of the tone alone. Freezing was extinguished after 4 tone‐alone trials in all FC groups except female I/R rats which showed increased freezing in later tone‐alone trials (P<0.01). Female I/R rats subjected to FC also showed increased tone‐induced locomotion (reminiscent of escape seeking behavior) in early tone‐alone trials that was not displayed by any other group (P<0.05). Sixty minutes after the fourth tone‐alone trial, rats were euthanized and cardiac mast cell density and degranulation were determined through the dorsal base of the heart surrounding the pulmonary veins and intracardiac ganglia. Density of inflammatory cardiac mast cells did not differ between groups. However, female FC I/R rats showed more mast cell degranulation than their PC I/R control group (27.2±3.2 vs. 20.2±2.1%, P<0.05). Cardiac mast cell degranulation did not differ between any other FC group and their respective PC controls. Similar numbers of mast cells from female and male FC rats exposed to I/R showed TNF‐α expression (221.6 ± 11.3 vs 211.4 ± 12.5). Thus, I/R induces greater emotional reactivity in cycling female rats, which in turn stimulates more degranulation of mast cells containing pro‐inflammatory cytokines. These results suggest a possible link between PTSD and the increased mortality reported in pre‐ and perimenopausal women after MI.

Support or Funding Information

Supported by American Heart Association Mid‐West Affiliate Grant‐in‐aid 14GRNT20380765
Impaired Autonomic Regulation in Posttraumatic Stress Disorder
Authors: Swiercz Adam P , Park Jeanie , Hopkins Lauren , Moshfegh Cassandra , Wiaderkiewicz Jan , Young Colin N , Marvar Paul J
Published: November 2023

Post‐traumatic stress disorder (PTSD) is associated with a significantly increased risk of cardiovascular disease (CVD) and accumulating clinical evidence suggests that autonomic dysregulation due to sympathetic overactivity and/or parasympathetic insufficiency may contribute to progression of CVD in PTSD. Therefore, utilizing a translational approach, we sought to examine autonomic function in both a clinical PTSD population as well as in an animal model of PTSD. In experimental studies, mice were instrumented with radiotelemetry probes to evaluate autonomic indices following Pavlovian fear conditioning. Fear conditioning involves the pairing of a conditioned stimulus (e.g. tone) paired with an aversive uconditioned stimulus (e.g. foot shock) that evokes a conditioned response (e.g. freezing). Twenty‐four hours following fear conditioning, spectral analysis of heart rate was performed and the low‐to high‐frequency ratio (LF:HF) was used as an index of sympathovagal balance. Fear conditioned animals displayed a significant increase in the LF:HF ratio relative to baseline (1.21 ± 0.46; p<0.05) indicating a shift in sympathovagal balance. Two weeks following fear conditioning, we assessed the contribution of sympathetic activity to the maintenance of blood pressure using the ganglionic blocker chlorisondamine (12ug/g i.p.). In response to sympathetic nervous system blockade, fear conditioned animals had a greater fall in blood pressure compared to control (Δ Systolic −71.7± 1.9 vs −39.8 ± 5.8 mmHg; p<0.05). Collectively, these results suggest impairments in autonomic control in an animal model of PTSD prior to the onset of CVD. Finally, these findings will be compared to an ongoing clinical study using a population of combat‐related PTSD (n=13) versus age‐matched controls without PTSD (n=9). Continuous elecrocardiography, beat‐to‐beat arterial blood pressure (BP) measurements, and 24‐hour ambulatory BP measurements have been collected at rest, during, and following mental stress. In an effort to translate our pre‐clinical results, these data will be analyzed for spectral analysis of heart rate variability, BP variability, and 24‐hour ambulatory BP patterns.

Support or Funding Information

NIH R00 HL107675‐03 American Heart Association ‐ 15CSA24340001
Pigs Fed a Western Diet Develop Elevated Fasting Glucose and a Microbiome Analogous to Human Obesity
Authors: Hintze Korry , Cox Lindsay , Lefevre Michael , Isom S. Clay
Published: November 2023

Previously we developed the Total Western Diet (TWD) for mice, a basal diet that emulates average American intakes for both macro and micronutrients. To extend the model, the TWD for pigs was formulated using the principle of nutrient density (mass of nutrient/kcal/day). As a model for a typical Western Diet, we selected the 50th percentile daily intake levels for macro and micronutrients from the National Health and Nutrition Examination Survey (NHANES). The relative contribution of total carbohydrates, fats, protein and micronutrients to total calories consumed at the NHANES 50th percentile was determined; these ratios were then used to formulate the pig TWD. The carbohydrate content of the TWD was further portioned into either simple or complex carbohydrates to match NHANES data. The fat portion of the TWD contains a diverse set of fat sources in order to match the dietary fatty acid profile reported in NHANES. To determine effects of the TWD on metabolism and the microbiome, ten female, mature pigs were assigned to either the TWD (n=5) or a control (CON), low‐fat commercial sow diet (n=5). Pigs were fed for 12 weeks and allowed ad lib access to diets. Blood and fecal samples were collected at baseline, 6 weeks and 12 weeks to determine effects of treatment on fasted glucose and taxonomy of the microbiome. Pigs fed the TWD gained significantly more weight, 92.8 ± 9.5 vs. 54.2 ± 11.2 kg (p < 0.001) and had an increased fasted blood glucose, 123.2 ± 13.7 vs 91.4 ± 7.9 mg/dl (p < 0.01) compared to control pigs. Principal coordinates analysis using unweighted Unifrac distance revealed that dietary treatment caused distinct microbiomes after 6 weeks of feeding. Moreover, pigs fed the TWD shifted from a Bacteroidetes to Firmicute dominated microbiome after 12 weeks on treatment (p < 0.01). The microbiome of pigs fed the CON diet remained Bacteroidetes dominant. These data suggest that the American diet pattern when fed to pigs is obesegenic, diabetogenic and causes shifts in the microbiome associated with obesity in humans.

Support or Funding Information

Utah Sate University SPARC Grant Program
Soluble and Insoluble Fiber Differentially Impact Canine Fecal Microbiome and Circulating Metabolome
Authors: Jackson Matthew Irick , Jewell Dennis Edward
Published: November 2023

Dietary fiber comprises polysaccharides having heterogeneous properties; a practical distinction in fiber types is soluble versus insoluble. All fiber types bypass digestion and absorption in the upper gastrointestinal tract to become available for metabolism by colon‐resident gut microbiota. We sought to gain insight into the impact of dietary fiber type on the gut microbiome and circulating metabolome in healthy canines. Two diets were formulated to contain approximately equal macronutrient makeup and total dietary fiber, but to differ in soluble fiber percentage (high soluble fiber = 3.9%; low soluble fiber = 0.8%) with balance provided by insoluble fiber. We compared the time resolved changes in fecal microbiome (weekly) and serum metabolome (monthly) dogs consuming these two levels of soluble fiber (n =15) for 13 weeks. Dogs were housed in pairs, provided daily group exercise in outdoor grassy runs and had access to natural light that varied with season. Health was monitored via clinical and physical indices. Blood and fecal collections were carried out under IACUC approved protocols. Endpoints included serum metabolome and fecal microbiome; multiple coinertial analysis was used to indicate the relative capacity of these ‘Omes to explain sample variation. Typical patterns of microbiome response encountered were: 1) Taxa changes similar in direction and magnitude for both Diets (increased Bifidobacterium, Blautia, Ruminococcus); 2) Taxa changes similar in direction but not magnitude (increased Bacteroides, Prevotella‐less so with high soluble fiber); 3) Taxa changes in opposite direction for each Diet (Lactobacillus). A machine learning genetic algorithm provided microbial taxa best defining diet group identity. Microbial‐derived metabolites were also altered in serum according to diet consumed. Circulating tryptophan metabolites (e.g. indolelactate, indoleacetate, indoleacrylate) were decreased by low soluble fiber but increased by high soluble fiber. Somewhat similarly, circulating p‐cresol sulfate, O‐methylcatechol sulfate and catechol sulfate were decreased by low, but not high soluble fiber consumption. In contrast, 4‐ethylphenylsulfate and its unsaturated congener 4‐vinylphenylsulfate were decreased by both diets. Serum metabolite changes were associated with gut microbial function via ecological RLQ‐4th Corner analysis on PICRUSt imputed metabolic potential. In summary, differential dietary soluble fiber levels produced changes in canine fecal microbiome and serum metabolome, and these changes are in part correlated through imputed microbial gene functional capacity.

Support or Funding Information

Both authors employed by, and study funded by, Hill's Pet Nutrition, Inc. Science and Technology Center, Topeka, KS 66601
Responses of Inflammatory Cytokines Following Moderate Intensity Walking Exercise in Overweight or Obese Individuals
Authors: Garza Gustavo Axel , Solis Leslie , Park Kyung‐Shin , Koh Yunsuk
Published: November 2023

Chronic low‐grade inflammation is associated with physical inactivity as well as overweight and obesity. Levels of pro‐/anti‐inflammatory cytokines are affected as body fat changes. However, the response of these cytokines to short term moderate intensity exercise training is not yet known.

PURPOSE

The current study investigated the effects of a 4‐week moderate intensity walking exercise on levels of C‐reactive protein (CRP), TNF‐alpha and adiponectin in overweight or obese individuals.

METHODS

Twenty seven (13 males and 14 females) physically inactive, overweight or obese (BMI > 25.0 kg/m2) individuals participated in the study. Each participant was randomly assigned to either exercise (EX, N=15) or control (CON, N=12) group. The exercise group performed moderate intensity walking exercise on a treadmill for 60 minutes at 70% of HRmax for 4 weeks (3 days/week), while the control group did not perform any physical activity. Overnight fasting blood samples were collected before and after the study period (PRE and Post) to analyze levels of pro‐/anti‐inflammatory cytokines such as C‐reactive protein (CRP), TNF‐α, and adiponectin. Two‐way repeated measures ANOVA and Tukey post hoc tests were used for data analysis.

RESULTS

CRP and adiponectin as well as body weight and body composition were not significantly altered following the 4‐week exercise intervention. However, there was a significant group*time interactions for TNF‐α. The follow‐up simple effects tests revealed that only the exercise group significantly lowered level of TNF‐α (EX : 55.18±2.57pg/mL, Mean±SE, ← 50.31±2.22 P=.0084 vs. CON : 55.50±2.88 ← 58.19±2.48, P=.25). EX Post is also significantly lower as compared to CON Post (P=.032). Values for CRP and Adiponectin were as follows; CRP (EX : 637.8±113.3ng/mL, ← 510.5±114.2 P=.060 vs. CON : 644.2±126.7 ← 654.1±127.7, P=.76) and Adiponectin (EX : 7.1±1.3 ug/mL, ← 7.2±1.3 P=.87 vs. CON : 9.8±1.5 ← 9.9±1.5, P=.83).

CONCLUSION

Although there was no change in fat mass, 4 weeks of aerobic exercise was long enough to decrease levels of TNF‐α indicating physical activity independent from change in fat mass may affect level of inflammation . Results confirmed previous research that longer period of training accompanied with weight loss is required to induce changes in CRP and adiponectin.
Adiponectin is necessary for exercise training‐induced muscular hypertrophy and vascular adaptation
Authors: Gorman Katherine , Ghosh Payal , Behnke Bradley , Borodunovich Kyle , Lucero Tiffani , Alarcon David , Cowan Morgan , Hotta Kazuki , Starr Kaleb , Delp Michael , Muller‐Delp Judy M
Published: November 2023

Adiponectin has been reported to be produced by skeletal muscle fibers and to influence muscle phenotype. We tested the hypothesis that adiponectin is necessary for exercise training‐induced muscular hypertrophy and alterations of the resistance vasculature in skeletal muscle. Adult C57BL/6 wild‐type (WT) or homozygous adiponectin knockout (Adipo KO) mice were obtained at 10 weeks of age and underwent treadmill exercise training (12 m/min, 5° incline, 1 hr/day, 5 days/wk for 8 wks) or remained sedentary in cages. Body mass was recorded weekly during the training/cage confinement period. At the end of the training/cage confinement period, the gastrocnemius‐plantaris‐soleus complex was isolated, and soleus muscle feed arteries were isolated for study of vascular responses to increasing intraluminal pressure (the myogenic response). The body mass of WT mice increased significantly over the training/cage confinement period, by 11.7% in sedentary mice and by 13.9% in exercise trained mice. In Adipo KO mice, body mass increased by 15.1% in sedentary mice (P<0.01 wk 8 vs wk 1), but increased by only 7.2% in exercise trained mice (P=0.07). In WT mice, the masses of both the soleus muscle (20.4±2.3 mg vs. 12.2mg; exercise trained vs. sedentary; P<0.01) and the gastrocnemius muscle (248.8 mg vs. 178.5 mg; exercise trained vs. sedentary; p<0.01) were greater in exercise trained mice as compared to sedentary mice. When expressed relative to body mass (muscle weight:body weight), these increases in mass persisted in the muscles of the exercise trained mice. In Adipo KO mice, exercise training did not increase the mass of either the soleus (12.5±1.5 mg vs. 12.1±1.5 mg; exercise trained vs. sedentary; P=0.62) or gastrocnemius muscle (195.2±11.2 mg vs. 182.7±18.9 mg; exercise trained vs. sedentary; P=0.12), whether expressed as absolute muscle mass or relative to body mass. Exercise training increased myogenic responsiveness of soleus muscle feed arteries significantly in WT mice (P<0.01, WT exercise trained vs. WT sedentary), but did not alter myogenic responsiveness of soleus muscle feed arteries in Adipo KO mice (P=0.87, Adipo KO exercise trained vs. Adipo KO sedentary). These results indicate that exercise training‐induced hypertrophy of skeletal muscle and associated improvement of vascular function does not occur in mice deficient in adiponectin. These results suggest that adiponectin is vital to the vascular and metabolic adaptations that occur in skeletal muscle in response to aerobic exercise training.
Ibuprofen Pre‐Treatment Increases Biomarkers of Heat Stroke Severity and Attenuates Fever during Recovery in Conscious Rats
Authors: Audet Gerald N , Duran Rocio M , Ward Jermaine A , Leon Lisa R
Published: November 2023

Heat stroke (HS) is a significant environmental threat to both military and civilian populations. We have shown previously in aconscious rodent model that non‐steroidalanti‐inflammatory drugs (NSAIDs) compound HS induced organ damage. Ibuprofen (IB) is one of the top prescribed NSAIDs globally and there are over 450,000 prescriptions for IB in US War fighter population alone, which does not include non‐prescription use. Yet, the effects of IB on HS morbidity have never been investigated. In the current study, we examined what effect a single pre‐dosage of IB has on physiological parameters during HS recovery in a new exertional heat stroke (EHS) rodent model. Fischer 344 rats were implanted with radio telemetry devices that continuously monitor core temperature (Tc),heart rate (HR), and mean arterial blood pressure (MAP). Rats were given either a single dose(62mg/Kg) of IB or vehicle (V, gum arabic) via oral gavage immediately prior to heating. Rats were then forced run(2–8m/min custom interval program) on a specialized heat‐specific running wheelat an ambient temperature of 37°C until cardiovascular crisis/compensatory failure (HR 608 ± 2 BPM; MAP 179 ± 1 mmHg). Rats were sacrificed at 5 days and organs were harvested for molecular and histological analysis. We found that those animals receiving IB had significantly higher temperatures at a given time point during heating (30 min sheating: IB 40.4 ± 0.1, V 40.0 ± 1 P<0.01; 45mins heating: IB 41.6 ± 0.1, V 41.2 ± 0.1 P<0.05), suggesting a decrease in cooling performance during running. IB increased the incidence of physiological biomarkers of severity; IB was the only group with hypothermia after heating (Tc <37 °C, persisting through 24hrs), and had a significantly decreased MAP at 12 hours (IB= 102 ± 5, V= 119 ± 2, P<0.01). In those IB animals that did not experience hypothermia (60%), IB blunted the normal, mild, hyperthermic response found through 12hrs (IB Avg 37.8°C vs V38.4°C), suggesting for the first time that hyperthermia after EHS is a true febrile response. IB had no effect on control animals (those that were unheated). In conclusion, IB may be decreasing performance during heating, inducing increased morbidity during EHS recovery, and could be altering protective physiologic responses. Author views not official US Army or DoD policy.
Exercise‐induced protection against ventilator‐induced diaphragm atrophy is dependent upon increased diaphragmatic levels of manganese superoxide dismutase
Authors: Morton Aaron B , Smuder Ashley J , Wiggs Michael p , Hall Stephanie E , Wawrzyniak Nicholas R , Powers Scott K
Published: November 2023

Mechanical ventilation (MV) is a life‐saving intervention for patients unable to sustain adequate pulmonary gas exchange on their own. Unfortunately, prolonged MV results in rapid atrophy and contractile dysfunction of the diaphragm, collectively termed ventilator‐induced diaphragm dysfunction (VIDD). Although the mechanisms responsible for VIDD remain elusive, it is established that increased mitochondrial production of reactive oxygen species is required for the development of VIDD. Notably, recent evidence reveals that endurance exercise training performed prior to MV is sufficient to protect the diaphragm against VIDD. While the mechanisms responsible for exercise‐induced prevention of VIDD remain unknown, evidence suggests that endurance exercise training may reduce diaphragm oxidative damage by elevating endogenous antioxidant enzyme expression. Therefore, these experiments tested the hypothesis that endurance exercise‐induced protection against VIDD is dependent upon increased diaphragmatic levels of the mitochondrial antioxidant enzyme, manganese superoxide dismutase (MnSOD). Cause and effect was determined by administering an antisense oligonucleotide against MnSOD to prevent the exercise‐induced increase in diaphragmatic MnSOD. Our data confirm that exercise training performed prior to prolonged MV results in protection against VIDD. Importantly, prevention of the exercise‐induced increases in diaphragmatic MnSOD resulted in a loss of exercise‐mediated protection against MV‐induced diaphragm atrophy. In contrast, prevention of exercise‐induced increases in MnSOD did not result in a loss of exercise‐induced protection against MV‐induced diaphragm contractile dysfunction. Collectively, these results reveal that while increases in diaphragmatic levels of MnSOD contribute to exercise induced protection against VIDD, increased MnSOD is not the sole mechanism responsible for exercise‐induced protection against VIDD.

Support or Funding Information

Supported by NIH R01 AR064189 awarded to SKP
14 days of bed rest induces a decline in satellite cell content and robust atrophy of skeletal muscle fibers in middle‐aged adults
Authors: Arentson‐Lantz Emily J , English Kirk L , Paddon‐Jones Doug J , Fry Christopher S
Published: November 2023

We examined the effect of 14 days of bed rest on skeletal muscle satellite cell content and fiber type atrophy and in middle‐aged adults. Bed rest, a ground‐based space flight analog, induces robust atrophy of skeletal muscle, an effect that is exacerbated with increasing age. With the average age of astronauts increasing, we wanted to determine the mechanistic changes during bed rest on an understudied age‐cohort. Muscle biopsies were obtained from the vastus lateralis of healthy middle‐aged adults (n=7 [4M;3F]; age: 51.0±0.6 y) before (Pre‐BR) and after (Post‐BR) 14 days of bed rest. Immunohistochemical analyses were used to quantify myosin heavy chain (MyHC) isoform expression, cross‐sectional area (CSA), satellite cell and myonuclear content and capillary density. Peak oxygen consumption and body composition were measured Pre‐ and Post‐BR. Post‐BR MyHC Type 2a fiber percentage was reduced and mean CSA decreased in all fiber types (25% decrease; P<0.05). Satellite cell content was also reduced Post‐BR (41% decrease; P<0.05), while Pre‐BR Type 2 satellite cell frequency was correlated with the decline in leg lean mass as measured by DXA scan. A decline in capillary density was observed Post‐BR (25% decrease; P<0.05), and Post‐BR capillary density was associated with Post‐BR peak oxygen consumption. A subtle decline in myonuclear content occurred during bed rest. The rapid maladaptation of skeletal muscle to 14 days of mechanical unloading in middle‐aged adults emphasizes the need for appropriate counter measures to preserve muscle function in astronauts.

Support or Funding Information

Funded by NSBRI grant NNJ08ZSA002N, NIH R01NR012973 (Paddon‐Jones), a Texas Space Grant Consortium Fellowship (English), NIH grant T32HD007539, and in part by the UTMB Claude D. Pepper Older Americans Independence Center NIH/NIA grant #P30 AG024832 and grant 1UL1RR029876‐01 from the National Center for Research Resources. The study was conducted with the support of UTMB's Institute for Translational Sciences, supported in part by a Clinical and Translational Science Award (UL1TR000071) from the National Center for Advancing Translational Sciences (NIH).
Autophagy is inhibited in hypertrophied skeletal muscle in response to 8 weeks of progressive resistance exercise
Authors: kwon insu , Jang yong‐chul , Cho Joon‐Yong , Lee Youngil
Published: November 2023

Although autophagy induced by endurance exercise is a catabolic adaptive process by which muscular biochemical and morphological alterations occur, the effects of resistance exercise used for enhancing anabolic processes on autophagy have not been clearly understood. Here, we showed that while 8 weeks of rigorous resistance exercise significantly increased muscle mass and strength, autophagy was repressed. Twenty male Wistar rats (age: 6 weeks) were randomly divided into two groups: sedentary control (SC, n=10) and resistance exercise (RE, n=10). After familiarized with ladder climbing, RE group performed the ladder climbing exercise as a resistance exercise (3 times/week for 8 weeks with progressively reinforced intensity). 48 hours after the last session of training, Flexor Digitorum Profundus (FDP) muscles were excised, weighed, and homogenized for western blot analysis. We found that the relative muscle mass in concordance with weight carrying capacity was significantly increased in RE group. Effective training stress was proved by increases in heat shock protein 72 (HSP72) and an antioxidant protein MnSOD levels, respectively. Intriguingly, we observed that RE antagonized an autophagic process evidenced by a decline in LC3 II/I ratio and an increase in p62 levels and that this phenomenon occurred without the alterations of Beclin‐1 and BNIP3 levels. To examine why RE dampened autophagic flux, we measured levels of LAMP2 and TFEB, a master regulator of lysosomal biogenesis and found that neither TFEB nor LAMP2 levels were changed. Interestingly, however, an active form of Cathepsin L level was markedly suppressed in RE group compared to SC. Taken together, our study suggests that muscular hypertrophy by RE is inversely related to autophagy possibly by inhibiting lysosomal degradation process.

Support or Funding Information

This project was supported by a grant from the University of west Florida through the Office of Research and Sponsored Programs.
Chronodisruption and Pregnancy
Authors: Gezahegn Beakal Meseret , Martin‐Fairey Carmel , England Sarah
Published: November 2023

Circadian rhythms are endogenous entrainable oscillations of approximately 24 hours. The tissues of the female reproductive system, from preovulation to parturition, are regulated by circadian rhythms. Studies have shown that disruptions of circadian rhythms during pregnancy result in adverse maternal (preterm birth and miscarriage) and fetal outcomes (impaired cognition). We hypothesize that knockout of chief circadian clock genes Per1/Per2, Clock, vasoactive intestinal polypeptide (VIP), and vasoactive intestinal polypeptide receptor (VIPR2) will decrease gestation length and impair offspring cognition. To test our hypothesis, we used C57BL/6 mice (WT) and mice deficient Per1/Per2, VIP, and VIPR2. These mice were blindly monitored throughout their pregnancies in a 12 hour light/dark cycle, with lights turning on at 7:00 AM and off at 7:00 PM. Archival data on mouse birth records did not provide a refined temporal resolution, but research in our laboratory indicates shorter gestation lengths in Per1−/−/Per2−/−knockout mice when mating was more discretely timed, with 1‐minute resolution. Preliminary results also show a difference in the frequency of certain behaviors attributed with sleep between genotypes. Mice that are either advanced or delayed in their cycles showed an uncharacteristic onset of sleep, occurring well before lights turned on. Other mice showed significant differences in frequency of behavior associated with wakefulness. This and further monitoring could help us get closer to understanding the link between circadian rhythms and the timing of birth.

Support or Funding Information

Acknowledgements: Thank you to the Herzog Lab and the England Lab at Washington University, as well as APS STRIDE Undergraduate Summer Research Fellowship, supported by the American Physiological Society and a grant from the National Heart, Lung and Blood Institute (NHLBI; 1 R25 HL115473‐01), and March of Dimes.