bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic systemic inflammatory challenge induced by LPS promotes cognitive impairment
Authors: Schirmbeck Gabriel Henrique , Da Ré Carollina Fraga , Seady Marina , Fróes Fernanda , Silva Sthefani Gomes , Taday Jéssica Hauschild , Gonçalves Carlos Alberto Saraiva , Leite Marina Concli
Published: June 2021

Neuroinflammation is a major component in the progression of neurodegenerative diseases such as dementia, although is not its main initiator. Its been demonstrated that inflammatory activation of microglia and astrocytes promotes protein aggregation of amyloid plaques and tau tangles, leading to neuronal death through other mechanisms, such as excitotoxicity. Although many studies investigated the effect of systemic inflammation on the progression of dementia and amyloid plaques in genetic mouse models of Alzheimer's disease, is not clear if systemic inflammation can induce dementia per se.

Methods

90‐day Wistar rats were exposed to chronic inflammatory challenges with intraperitoneal injections of LPS in two doses (500 μg/kg and 250 μg/kg) or saline once a week, for a 16‐week period. Rats were euthanasied 24 h after last LPS injection. Behavioral evaluation was conducted through Open Field (OF) and Object Location Memory‐Test (OLM) for spatial memory assessment. Hippocampal S100B content was measured by ELISA, nuclear Nf‐κB was measured by western blot, and L‐[3H] glutamate uptake was analyzed.

Results

Both groups receiving LPS presented impaired spatial memory in the 24 h OLM, which is characteristic of hippocampal degeneration in animal models of dementia, while OF shown no locomotor impairment. S100B protein remained unchanged between groups, and glutamate uptake was reduced only in LPS 500 μ/kg group. Nuclear fraction of Nf‐κB was increased in both LPS groups.

Discussion

Here, we demonstrate that chronic peripheral inflammatory stimuli promote cognitive impairment in the absence of other underlying neurodegenerative causes, such as genetic background. Increased Nf‐κB in nucleus indicates hippocampal neuroinflammation, despite LPS challenge being peripheral. Besides, glutamate uptake was reduced in the higher dose of LPS, indicating a possible excitotoxic damage. Conversely, S100B content, which is an important biomolecule in inflammatory signaling, was not affected by LPS.

Support or Funding Information

This study was supported by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), and Fundação de Apoio a Pesquisa do Estado do Rio Grande do Sul (FAPERGS)

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Denervation of carotid chemoreceptors decreases blood pressure in an ovine model of renovascular hypertension
Authors: Ramchandra Rohit , George Bindu , McBryde Fiona , Tromp Tycho , Chang Joshua
Published: June 2021

Background

Hypertension is a major health problem of pandemic proportions that is often inadequately controlled, warranting development of new treatments. There is increasing evidence that hypertension is initiated and maintained by elevated sympathetic nerve activity. There is also strong evidence that aberrant afferent signalling from carotid chemoreceptors promotes sympathoexcitation and hypertension. We hypothesized that hypertension is associated with activation of carotid chemoreceptors and that carotid sinus denervation (CSD) would reduce blood pressure.

Methods

Adult ewes either underwent unilateral renal artery clipping or sham surgery. Three weeks later, baroreflex control of heart rate was examined and the contribution of sympathetic mechanisms to hypertension was determined using hexamethonium (125 mg/hr). The mean arterial pressure and renal blood flow response to activation of carotid chemoreceptors was determined in both groups. In a second surgery conducted in hypertensive animals only, the carotid sinus nerve was severed bilaterally (CSD) (n=6) or left intact (sham, n=6) and the effect on blood pressure was examined.

Results

Unilateral renal artery clipping induced hypertension (mean arterial pressure 109 ± 2 vs 91 ± 3 mmHg in shams, p<0.001). The pressor response and the renal vasoconstriction response to chemoreceptor activation was augmented in hypertensive animals compared to the normal group (for e.g. MAP response, 15 ± 1 vs 7 ± 2 mmHg, p<0.05). CSD decreased MAP (−17 ± 1 vs +2 ± 1 mmHg in shams, p<0.0001) and shifted the heart rate baroreflex curve to the left. The contribution of the autonomic nerves to hypertension was elevated in hypertensive animals compared to normal (−19 ± 2 vs −11 ± 2 mmHg, p<0.05) and CSD reduced this contribution.

Discussion

In conclusion, we have shown that hypertension in our large animal model is associated with activation of carotid chemoreceptors and that bilateral CSD lowers arterial pressure. Our data implicates the carotid chemoreceptors in the maintenance of renovascular hypertension.

Support or Funding Information

Funded by the University of Auckland Faculty Research Development Fund and the Health Research Council of New Zealand.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
ERYTHROPOIETIN NEUROPROTECTIVE PROPERTY AS NEW AS THERAPEUTIC TOOL FOR APNEA OF PREMATURITY
Authors: SOFIEN LAOUAFA , JOSEPH VINCENT , BAIRAM AIDA , SOLIZ JORGE
Published: June 2021

We tested the hypothesis that Epo (Erythropoietin) protects newborns against the consequences of IH induced by apnea of prematurity (AoP). As caffeine (despite ineffective in about 50% of cases) is the treatment of choice of AoP, the effect of Epo and caffeine was compared.

Male and female newborn rats exposed to IH during postnatal days (P) 3–10 were used in this work. During this time, animals were daily gavage with vehicle, Epo, caffeine, and Epo+caffeine (10–12 pups/group). At P10 the frequency of apneas and mean duration of apnea at rest were measured (as index of respiratory dysfunction induced by IH) plethysmography. Next, the hippocampus, cortex, and brainstem were harvested, and the activity of Superoxide‐Dismutase (SOD – major anti‐oxidant), Glutathion peroxydase (GPx) and NADPH oxidase (NOX – major pro‐oxidant) enzymes were evaluated.

Our results showed that IH increased the frequency of apnea and mean duration of apnea in male and female, reduced SOD anf GPx activity, but increased NOX activity. Interestingly, Epo and caffeine significantly reduced apnea frequency, but only Epo efficiently restored the oxidant activity to normal levels. Moreover, the administration of Epo and caffeine together provided cumulative beneficial effects in reducing the apneic episodes in male and female pups.

We conclude that Epo and caffeine activate different, but complementary mechanisms to decrease apneas, suggesting that combined Epo+caffeine treatment could be clinically relevant against AoP.

Support or Funding Information

Founded by CIHR, Région Rhône alpes and consulat de France à Québec.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Cellular Senescence in the Brainstem: Implications for Age‐Related Sympathetic Nervous System Dysregulation
Authors: Branen Lyndee , Balasubramanian Priya , Subramanian Madhan
Published: June 2021

Aging is an independent risk factor for cardiovascular diseases such as hypertension and heart failure. Evidence from the literature suggests that sympathetic nervous system (SNS) dysregulation may play a causative role in age‐associated increased risk for cardiovascular diseases. The mechanisms underlying this phenomenon remains largely unknown. Senescent cells are known to accumulate in various tissues of the body with age and are implicated in the pathogenesis of several neurodegenerative diseases. Senescent cells are known to secrete cytokines, chemokines, and proteases through the acquisition of senescence‐associated secretory phenotype (SASP) and contribute to neuroinflammation in age‐related diseases. However, the presence of senescent cells in the brainstem, a region that contains several nuclei regulating sympathetic outflow and blood pressure has not been investigated. We hypothesized that senescent cells accumulate in the brainstem with age and promotes neuroinflammation, thereby contributing to age‐related SNS dysregulation. To test this, we isolated brainstem from young (2–4 months) and aged (24 months) male C57BL/6J mice (n=4–5/group) and performed gene expression analysis for cellular senescence markers and SASP using qPCR. Data were analyzed with students t‐test and expressed as mean ± S.E. Our results show significant increases in the mRNA expression of p16Ink4a (1.22 ± 0.4 vs 32.89 ± 8.78 fold, young vs aged, p<0.05) a well‐known senescence marker and pro‐inflammatory cytokines, and proteases like IL‐1β (1.03 ± 0.14 vs 2.13 ± 0.29 fold, p<0.05), MCP‐1 (1.02 ± 0.11 vs 4.33 ± 0.79 fold, p<0.05), IL‐1α (1.07 ± 0.2 vs 3.83 ± 0.73 fold, p<0.05, TNFα (1.06 ± 0.21 vs 4.48 ± 1.05 fold, p<0.05) and a trend for an increase in MMP3 in the aged brainstem, presenting evidence for senescence and SASP. We did not observe any age‐related changes in expression of metabotropic or ionotropic glutamate receptors, suggesting that the excitatory neurotransmitter machinery may not be altered in the brainstem with aging. Here we present, for the first time, evidence for cellular senescence in the brainstem of aged mice. Future studies will investigate the mechanistic role of senescence cells in the brainstem in age‐related SNS dysregulation.

Support or Funding Information

RAC fund, CVHS, Oklahoma State University

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The neural control of arterial pressure by non‐catecholaminergic RVLM
Authors: Holloway Ben , Abe Chikara , Stornetta Daniel , Stornetta Ruth , Guyenet Patrice
Published: June 2021

Tonic sympathetic nerve activity (SNA) is necessary for the maintenance of arterial pressure (AP) under anesthesia, and this tone is dependent on supraspinal input. Over the last two centuries, numerous studies have collectively identified the rostral ventrolateral medulla (RVLM) as a critical region for neural control of AP and SNA in anesthetized animals, however the relevance of these results to conscious animals and the nature of the RVLM neurons responsible remain conjectural. The RVLM has direct projections onto sympathetic preganglionic neurons, but the evidence that this is the critical pathway for AP regulation and SNA in conscious animals is not definitive—and even if this is the principal BP regulatory pathway of the RVLM, the bulbospinal neurons that produce these effects are still debated.

Historically, the most prominent pressor candidate within the RVLM has been the rostral portion of the catecholaminergic C1 group. Rostral C1 neurons are glutamatergic, occupy a ventral region of the medulla that is coextensive with the vasomotor RVLM region, are barosensitive, directly innervate sympathetic preganglionic neurons, and activate sympathetic nerve discharge upon stimulation. Despite these data, optogenetic stimulation of C1 in conscious and anesthetized rodents has thus far failed to achieve the magnitude of increases in arterial pressure predicted by pharmacological stimulation of the RVLM.

Here, we show that stimulation of a non‐catecholaminergic population within the RVLM is sufficient to increase AP in conscious mice, even after C1 lesion. We then targeted bulbospinal neurons using a retrograde virus and demonstrated that optogenetic activation of only bulbospinal RVLM neurons increases AP in conscious mice, and in anesthetized mice, stimulation increases AP and renal sympathetic nerve activity. Unlike optogenetic stimulation of C1 neurons, stimulation of non‐catecholaminergic bulbospinal RVLM causes robust and sustained increases in AP in both conscious and anesthetized states, and sustained increases in SNA under anesthesia. This data suggests non‐catecholaminergic bulbospinal neurons are powerful activators of AP and SNA and may play an important role along with C1 in arterial pressure maintenance.

Support or Funding Information

American Heart Association Predoctoral Fellowship; University of Virginia Wagner Fellowship

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Impact of Chronic Antioxidant Administration on Sympathetic Nervous System Activity and Vascular Function in Heart Failure Patients with a Reduced Ejection Fraction
Authors: Bunsawat Kanokwan , Ratchford Stephen M , Theisen Jeremy K , Park Soung‐Hun , Stehlik Josef , Wever‐Pinzon Omar , Drakos Stavros , Richardson Russell S , Wray D. Walter
Published: June 2021

Background

Heart failure with reduced ejection fraction (HFrEF) is characterized by sympathetic nervous system (SNS) overactivation and vascular dysfunction, two important predictors of mortality and morbidity in this patient group. Importantly, oxidative stress, defined as an excess production of free radicals relative to antioxidant defenses, is prevalent in patients suffering from HFrEF. This pro‐oxidant state is associated with attenuated nitric oxide bioavailability, which may contribute to increased SNS activity and vascular dysfunction. While chronic oral antioxidant (AOx) administration has been documented to mitigate oxidative stress in other populations, the efficacy of this approach to improve autonomic and vascular function in patients with HFrEF has not been evaluated. Thus, this study sought to determine the effect of chronic (30‐day) over‐the‐counter oral AOx administration on SNS activity and vascular function in patients with HFrEF.

Methods

Five HFrEF patients (71 ± 3 yrs; 28.5 ± 1.5 kg/m2) were studied before and after 30 days of oral AOx administration (Vitamin C, 1000 mg; Vitamin E, 600 IU; α‐lipoic acid, 600 mg; QD). Resting muscle sympathetic nerve activity (MSNA) was assessed for the determination of SNS activity, and vascular function was evaluated by brachial artery flow‐mediated dilation (FMD) testing. Venous blood samples were also collected for the direct determination of plasma free radical concentration (electron paramagnetic resonance spectroscopy, EPR).

Results

Chronic antioxidant administration reduced MSNA burst frequency (pre: 44 ± 3 bursts/min; post: 38 ± 2 bursts/min, p<0.05). FMD appeared to improve following AOx administration (pre: 2.7 ± 0.7%; post: 4.0 ± 1.0%), but this change did not reach statistical significance (p=0.18). A tendency for a reduction in plasma free radical concentration following AOx administration (pre: 3.2 ± 1.6 AU; post: 0.7 ± 0.1, p=0.11) was also observed.

Conclusion

Chronic antioxidant administration significantly reduced SNS activity and tended to improve vascular function, supporting the efficacy of this simple therapeutic approach to improve autonomic and vascular function in patients with HFrEF.

Support or Funding Information

This project is funded in part by the National Institutes of Health (HL118313) and the U.S. Department of Veterans Affairs (RX001697, RX001418, E6910R).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Normobaric hyperoxia ameliorates renal ischemia reperfusion injury in rats
Authors: Nensén Oskar , Hansell Peter , Palm Fredrik
Published: June 2021

Introduction

Acute kidney injury (AKI) represents an ever‐increasing clinical problem with high morbidity and mortality. The kidney, due to its inhomogeneous blood flow, is particularly susceptible to changes in oxygen delivery. Renal hypoxia constitutes a common hallmark of AKI, and in the progression to chronic kidney disease (CKD). However, the role of hypoxia per se in the acute phase of renal injury remains largely unclear. The present study investigated 1) the role of systemic hypoxia in the acute progression and recovery of AKI, and 2) if normobaric global hyperoxia following AKI improves renal outcome.

Methods

Anaesthetized (thiobutabarbital 120mg/kg i.p.) adult male Sprague‐Dawley rats were subjected to unilateral complete warm renal ischemia for 45 minutes followed by 2 hours of reperfusion under normoxic (21% inspired oxygen, n=10), hypoxic (10% inspired oxygen, n=10), and hyperoxic (60% inspired oxygen n=10) conditions. Kidney function, renal hemodynamics, intrarenal tissue oxygen tension (PO2), and renal oxygen consumption were estimated before and after the ischemic insult.

Results

All investigated parameters were similar between groups at baseline. Animals subjected to 10% inspired oxygen developed intrarenal tissue hypoxia, whereas animals subjected to 60% inspired oxygen presented with increased intrarenal PO2 demonstrating that the approach to manipulate intrarenal tissue oxygen availability was successful. Furthermore, GFR at baseline were independent of renal tissue oxygenation.

IR per se caused a steep decline in GFR in all groups (−97 ± 1, −87 ± 3, and −70 ± 11% for hypoxic, normoxic and hyperoxic animals, respectively), although renal blood flow and renal vascular resistance were similar before and after the ischemic insult. However, following IR there was a linear relationship between GFR and cortical PO2 when analysing all animals in all groups (Fig 1, linear regression P<0.05).

Conclusion

This study demonstrates that renal function following IR is dependent on intrarenal oxygen availability. Furthermore, normobaric hyperoxia‐treatment initiated at the time of the ischemic insult has the potential to protect kidney function.

Support or Funding Information

This study was supported by the Swedish Research Council Medicine and Health.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Calcium‐dependent dual oxidase 2 is a novel source of reactive oxygen species implicated in glomerular mesangial cell fibrotic response to angiotensin II
Authors: Pedroza Aleksis Ramirez , Martinez Alexandra , Wauquier Fabien , Lee Doug‐Yoon , Gorin Yves , Ford Bridget M
Published: June 2021

The vasoactive peptide angiotensin II (Ang II) contributes to the initiation and the progression of glomerular fibrosis via activation of glomerular mesangial cells (MCs) and subsequent extracellular matrix expansion. We have previously shown that oxidative stress is critical for MC fibrotic response to Ang II. Here, we demonstrate that Dual oxidase 2 (Duox2), a member of the Nox/Duox family of NADPH oxidases, is present in MCs and that its protein expression is upregulated by Ang II.

Small interfering RNA (siRNA)‐mediated downregulation of Duox2 significantly reduces Ang II‐induced increase in reactive oxygen (ROS) generation and prevents the stimulatory effect of Ang II on MC fibrotic injury (as assessed by measuring a‐smooth muscle actin and fibronectin expression).

Duox2 activation is Ca2+‐dependent. Next, we investigated the role of Ca2+ in Ang II‐mediated Duox2 activation and the resulting fibrotic response. We show that the extracellular Ca2+ chelator BAPTA prevented Ang II‐induced ROS generation and the stimulation of MC fibrotic injury by Ang II. Moreover, treatment of MCs with ionomycin resulted in increased ROS production and enhanced MC fibrotic injury. These effects were abrogated by siRNA targeting Duox2. These data indicate that Ang II‐stimulated Duox2 activation and ROS generation subsequently lead to MC fibrotic injury.

In summary, we have identified a novel role for Duox2 as a major source of ROS in response to Ang II and established the significance of Duox2 in Ang II‐mediated MC activation and fibrotic injury. Therapeutic targeting of this pathway may prevent or reverse pathophysiologic manifestations of renal fibrotic diseases

Support or Funding Information

This project was funded by the University of the Incarnate Word, Office of Research and Graduate Studies and the following grants: NRSA 5T32HL007446‐32, NIH 1RO1DK07999601A2, and NIH UL1 TR001120/IIMS Pilot Project

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Female mice are protected against the renal pro‐inflammatory effects of a high‐salt diet during diabetes
Authors: Giani Jorge F , Hernandez Adela F , Bernstein Ellen A , Veiras Luciana C , Khan Zakir , Cao DuoYao , Peng Zhenzi , Bernstein Kenneth E
Published: June 2021

Introduction

High‐salt diet and hypertension are major contributors to diabetic nephropathy and predispose to end‐stage renal disease. In addition, studies in both humans and animal models of diabetes demonstrated that males have higher incidence of diabetic kidney disease compared to females.

Objective

We aim to determine the contribution of a high salt diet to the development of renal inflammation associated with diabetes in female versus male diabetic mice.

Methods

Four‐month‐old female and male db/db mice (a model of type 2 diabetes) and non‐diabetic controls were exposed to either a high (4% NaCl w/w) or control (0.4% NaCl w/w) diet for 3 weeks (n=4). Systolic blood pressure (SBP) was measured by the tail‐cuff method. At the end of the protocol, mice were euthanized, and kidneys were preserved to assess renal inflammation.

Results

A high salt diet did not modify the blood pressure in any experimental group. At the beginning of the high salt diet, SBP was 99 ± 8 mmHg in diabetic females and 100 ± 3 mmHg in diabetic males. After 3 weeks of high salt, SBP was 101 ± 4 mmHg in diabetic females and 106 ± 2 mmHg in diabetic males (P=NS). However, male diabetic mice exposed to high salt displayed higher abundance of renal TNFα (1.8‐fold increase, P<0.001), IL‐6 (1.9 fold‐increase, P<0.01) and IL‐1β (2.1‐fold increase, P<0.05) compared to equally treated diabetic females. Further, male diabetic mice displayed higher expression of renal NLRP3 inflammasome components such as Pro‐caspase‐1 (2.6‐fold increase, P<0.01), caspase‐1 (2.2‐fold increase, P<0.05) and the adaptor protein ASC (2.3‐fold increase, P<0.05) compared to female diabetic mice. Finally, the anti‐inflammatory cytokine IL‐10 was decreased in diabetic males exposed to a high salt diet compared to diabetic males receiving a control diet (from 563 ± 23 to 411 ± 21 pg/mg kidney protein, P<0.05). In female diabetic mice, IL‐10 remained unchanged. Both female and male non‐diabetic mice displayed no changes in response to a 3‐week high salt diet.

Conclusion

Even in the absence of salt‐sensitive hypertension, male diabetic mice are more susceptible to the renal pro‐inflammatory effects of a high‐salt diet compared to female diabetic mice.

Support or Funding Information

This study was supported by NIH R01HL142672, AHA 16SDG30130015, and P30 DK063491 (JFG); NIH R01HL110353 and AHA 17GRNT32580000 (KEB).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Controlling Glucose Handling via Renal Olfr1393 Offers Protection in a Type I Diabetic Mouse Model
Authors: Schiazza Alexis R , Shepard Blythe D
Published: June 2021

Olfactory receptor 1393 (Olfr1393) is a G‐protein coupled receptor that has vital functionality outside of its native environment in the nose. In recent reports, we have discovered that renal Olfr1393 localizes to the apical membrane of the renal proximal tubule (PT) where it aids in glucose reabsorption in both health and disease (through a diet‐induced obesity model of type II diabetes) via the sodium‐glucose co‐transporters. To identify additional roles for Olfr1393, we induced type I diabetes (T1D) in whole animal Olfr1393 wildtype (WT) and knockout (KO) male and female mice. Low dose Streptozotocin (STZ: 55 mg / kg BW) injections were administered for 5 consecutive days to deplete pancreatic β‐cells and induce insulin deficiency. Preliminary studies indicate that by 2 weeks post‐STZ, WT male mice develop hyperglycemia (2hr fasting blood glucose (mg/dl): WT diabetics – 383.3 ± 30.1 vs WT vehicle controls – 156.5 ± 24.5) and impaired glucose tolerance (area under curve in thousands (AUC) WT diabetics – 37.8 ± 5.8 vs WT vehicle – 19.8 ± 1.0). In keeping with its function in PT glucose reabsorption, compared to the diabetic WTs, KO mice have lower 2h fasting blood glucose values (Diabetic WTs: 383.3 ± 30.1 vs KOs: 272.7 ± 27.7) and improved glucose tolerance (AUC: Diabetic WTs: 37.8 ± 5.8 vs KOs – 30.1 ± 2.3). No significant differences were detected in insulin sensitivity between diabetic WT and KO mice. One hallmark of T1D is the development of glomerular hyperfiltration; notably, neither diabetic WT nor KO mice present with diabetic hyperfiltration by 5 weeks post‐STZ when measured by transcutaneous elimination kinetics of FITC‐sinistrin. Efforts are currently underway to determine the glomerular damage induced by our T1D model. Collectively, this study indicates that Olfr1393‐mediated control of renal glucose handling is important for the progression of T1D, likely through the regulation of the Sglts.

Support or Funding Information

NIDDK

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Store‐Operated Calcium Entry in Mesangial Cells and Glomerular Inflammatory Responses
Authors: Chaudhari Sarika , Shotorbani Parisa Yazdizadeh , Wang Yanxia , Ma Rong
Published: June 2021

Emerging evidence indicates that immunological and inflammatory mechanisms play a significant role in the development of diabetic nephropathy (DN). The early features of DN include accumulation of extracellular matrix (ECM) in the glomerular mesangium. Inflammatory cell infiltration mediated by locally produced cytokines/chemokines contributes to the histological impairment in DN. Glomerular mesangial cell (MC) is a major cell type in glomerulus to produce cytokines/chemokines in response to diabetes and a major contributor to mesangial expansion in DN. We have previously demonstrated that the Orai‐1 mediated store‐operated calcium entry (SOCE) suppressed ECM protein production by MCs. The aim of this study was to determine whether SOCE in MCs regulated cytokine/chemokine production by MCs and macrophage infiltration into glomerulus.

Methods

Orai‐1 channel protein in MCs was knocked down using the targeted nanoparticle‐siRNA delivery system in wild‐type C57BL6 mice at the age of 16 weeks. Immunohistochemistry was performed on the paraffin‐embedded kidney sections to examine macrophages infiltration in glomeruli using F4/80 as a marker. In cultured human MCs, the levels of various inflammatory cytokines (MCP‐1, TNF‐α, IL‐6) were examined using ELISA in the presence of normal glucose (5 mM D‐glucose + 20 mM L‐glucose) or high glucose (25 mM D‐glucose) with/without an activator (thapsigargin at 1 μM) of SOCE.

Results

In vivo knockdown of Orai1 in MCs induced infiltration of F4/80 stained macrophages into the glomeruli in the mice treated with nanoparticle/Orai1 siRNA for 5 days compared to the control mice. In cultured human MCs, 24‐hour treatment with high glucose significantly increased the expression levels of MCP‐1 and TNF‐α. The high glucose responses were significantly blunted by thapsigargin. However, high glucose treatment for 24 hours significantly decreased and activation of SOCE by thapsigargin significantly increased IL‐6 expression level in MCs.

Conclusion

Orai‐1 mediated SOCE in MCs inhibits the glomerular macrophage infiltration in mice and has differential effects on the expression of different cytokine/chemokines in MCs.

Support or Funding Information

NIH/NIDDK (1RO1 DK115424); AHA Southwest Affiliate (16GRNT27780043); Harry S. Moss Heart Trust Award.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Role of Sex and GPER in Renal Damage Induced by Ang II Hypertension
Authors: Aguerre Ines M. , Gentry Kaylee M. , Lindsey Sarah H.
Published: June 2021

The protective cardiovascular effects of estrogen are mediated by both the classic steroid receptors (ERα/β) and the novel G protein‐coupled estrogen receptor (GPER). We previously showed that genetic deletion of GPER does not alter the pressor response to Ang II but exacerbates pulse pressure and resistance artery contractility. The objective of the current study was to assess whether G protein‐coupled estrogen receptor (GPER) deletion is associated with evidence of renal damage in mice with intact ERα/β signaling. Male (M) and female (F) wildtype (wt) and GPER knockout (ko) mice were infused with Ang II (700 ng/kg/min) for two weeks. Kidneys were weighed, formalin‐fixed, and paraffin‐embedded. Renal damage was assessed in 4 mm sections mounted onto slides. Renal vascular fibrosis was quantified as percent of pixels with positive Masson's Trichrome staining, and renal infiltration was scored on a scale of 1–5 in sections stained with hematoxylin & eosin. Statistical analysis was completed using two‐way ANOVA. Kidney weights in Ang II‐infused mice were significantly higher in males (P< 0.0001) but were not impacted by GPER deletion (P=0.16; Fwt: 6.3 ± 0.2, Fko 6.1 ± 0.1, Mwt 7.6 ± 0.3, Mko 7.2 ± 0.2 mg/g body weight, n=7–9/group). Renal vascular fibrosis was not significantly affected by sex (P=0.29) or genotype (P=0.93). Interstitial infiltration was observed in the medulla, but there was no effect of sex (P=0.24) or genotype (P=0.58). Our findings indicate that neither sex nor GPER deletion significantly impacted renal damage in response to two week Ang II infusion. Future studies will determine whether sex and GPER play a role in renal damage when Ang II hypertension is induced for longer than two weeks.

Support or Funding Information

Funding was provided by NIH HL133619 to SHL. The STRIDE Fellowship is supported by the American Physiological Society and NIH HL115473.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Kynurenine Induces Renal Fibrosis which May Contribute to Bone Loss in Aging
Authors: Irsik Debra L , Xu Jianrui , Bollag Wendy B , Isales Carlos M.
Published: June 2021

Aging results in both bone loss and renal dysfunction, and the two conditions are interrelated. Low‐protein diets are recommended to increase longevity in the elderly but may occur at the expense of bone density. Tryptophan, an essential amino acid, is at greatest risk of depletion. Aging is marked by low tryptophan levels and higher levels of its oxidized metabolite, kynurenine (KYN). Feeding a low‐protein diet supplemented with KYN results in bone loss in younger mice; however, the renal effects of KYN have not been evaluated in this model. We hypothesized that KYN feeding induces bone loss and renal dysfunction through the fibroblast growth factor‐23 (FGF23)/α‐Klotho pathway involved in renal handling of calcium and phosphate and production of 1,25‐dihydroxyvitamin D. Male C57BL/6 mice (13 months old) were fed either a low‐protein (LP, 8%) or normal‐protein (NP, 18%) diet with or without KYN for 8 weeks. LP induced significant diuresis (2.16 ± 0.08 mL/day) that was attenuated with KYN (1.28 ± 0.10 mL/day). Glomerular filtration rate (GFR) was not different among the groups. Albuminuria was increased with age in the NP‐ or NP+KYN‐fed mice but not in the LP or LP+KYN groups. Tubulo‐interstitial fibrosis was present in LP‐ and LP+KYN‐fed mice and was not different from 24‐month‐old mice. Serum levels of FGF23 were elevated in LP‐fed mice but did not reach significance. Kidney protein levels of α‐Klotho declined with age. Our preliminary data suggest that KYN feeding may induce renal fibrosis that may contribute to bone loss, and FGF23/α‐Klotho may be involved. Further studies are needed to define a role for KYN in renal aging.

Support or Funding Information

PO1 AG036675 and AG036675S1

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
125Iodide as a Surrogate for 36Chloride in Tracing Transepithelial Intestinal Chloride Transport
Authors: Stephens Christine Elizabeth , Whittamore Jonathan Mark , Hatch Marguerite
Published: June 2021

Chloride (Cl−) transport by the large intestine is critically important, driving epithelial fluid secretion and absorption. Dysregulation of Cl− transport by the intestine results in diarrhea‐associated pathologies. Measurement of epithelial Cl− transport has long been achieved using the radioisotope 36Cl−. However, the price of 36Cl has sky‐rocketed, now costing over $100 per μCi compared to just $1.50 per μCi 15 years ago, making it prohibitively expensive and a barrier to future research. 125Iodide (125I−) has been used as an alternative to 36Cl− in some transport assays, including Cl− efflux and influx by cultured cells, but has never before been validated in parallel with 36Cl as an alternative for tracing transepithelial Cl− transport. The goal of this study was to examine whether 125I− can serve as a reliable surrogate for measuring Cl− transport by the intestinal epithelium. Under symmetrical short‐circuited conditions in the Ussing chamber, we simultaneously measured 36Cl− and 125I− fluxes across the cecum and distal colon from mice lacking the main Cl−/HCO3− exchanger, DRA (Slc26a3), relative to wild‐type controls. In addition, we used a cocktail of forskolin and 3‐isobutyl‐1‐methylxanthine (IBMX) to stimulate cAMP production and net Cl− secretion by these tissues. We found the unidirectional fluxes of 125I− correlated well with 36Cl− in all circumstances, even in the absence of DRA, with a significant R2 value of 0.86 across all fluxes, or higher (up to 0.93) when data was separated by genotype and intestinal segment. Unexpectedly, cAMP induced net Cl− secretion predominantly through a reduction in the absorptive, mucosal‐to‐serosal, Cl− flux rather than stimulating the secretory serosal‐to‐mucosal Cl− flux, which is noteworthy considering antidiarrheal drugs often target secretory processes. Also, rates of Cl− and I− absorption in DRA‐knockout mice were decreased by 79% and 50%, respectively, in the ceca, and 65% and 34% in the distal colon, suggesting this Cl− transporter may have a previously unrecognized role in I− uptake. In summary, we demonstrated 125I− is an adequate, cost‐effective alternative for tracing unidirectional Clfluxes across the intestinal epithelium. For example, the amount of 36Cl− used in this study cost $536 compared to a mere $4 worth of 125I−, thus making future research into epithelial Cltransport accessible. In addition, this study also provides insight into mechanisms of net Clsecretion and suggests that DRA may have a role in intestinal I− absorption.

Support or Funding Information

This study was supported by grants DK088892 and DK108755 to M. Hatch from the National Institutes of Health.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Genetic disruption of guanylyl cyclase/natriuretic peptide receptor‐A upregulates renal (pro)renin receptor expression in Npr1 null mutant mice
Authors: Periyasamy Ramu , Das Subhankar , Pandey Kailash N
Published: June 2021

Atrial and brain natriuretic peptides (ANP and BNP) activate guanylyl cyclase/natriuretic peptide receptor‐a (GC‐A/NPRA), which regulates blood pressure through inhibition of renin‐angiotensin‐aldosterone system (RAAS). The aim of the present study was to determine whether targeted‐disruption of Npr1 (encoding GC‐A/NPRA) upregulates pro(renin) receptor (P)RR expression and leads to activation of MAPKs in Npr1 gene‐knockout mice. The Npr1 homozygous (Npr1−/−; 0‐copy), heterozygous (Npr1+/−; 1‐copy), wild‐type (Npr1+/+; 2‐copy), and gene‐duplicated homozygous (Npr1++/++; 4‐copy) mice were utilized. The renal expression of (P)RR, ACE‐1, and AT1R were analyzed. To identify the canonical pathway of (P)RR, we administered ACE‐1 inhibitor (captopril), AT1R inhibitor (losartan), and MAPKs inhibitors (U0126 and SB203580) to all Npr1 mice. The renal expression of (P)RR was increased by 3‐fold in 0‐copy and 2‐fold in 1‐copy mice compared with 2‐copy mice, which was also associated with increased expression of ACE‐1 and AT1R genes. Similarly, the renal expression of phosphorylated MAPKs (p‐Erk1/2 and p‐p38) were enhanced by 3.5‐fold and 3‐fold, respectively, in 0‐copy mice with significant increases in 1‐copy mice compared with 2‐copy mice. Proinflammatory cytokines were also significantly elevated in Npr1 0‐copy and 1‐copy mice. Treatment with captopril and losartan did not alter the expression of (P)RR in any of the Npr1 mice genotypes. Interestingly, losartan significantly reduced the expression of p‐ERK1/2 and p‐p38 in the Npr1 mice genotypes. The present findings suggest that ablation of Npr1 upregulates (P)RR, MAPKs (p‐Erk1/2 and p‐p38), and proinflammatory cytokines in 0‐copy and 1‐copy mice. In contrast, the duplication of Npr1 gene copy exhibited anti‐inflammatory and antihypertensive effects by reducing the expression of RAAS components, MAPKs, and proinflammatory cytokines.

Support or Funding Information

This work was supported by NIH grants (HL057531 and HL062147).

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Hormonal Regulation of Estrogen Receptors
Authors: Wilkinson Mary Margaret , Lindsey Sarah H.
Published: June 2021

Background

We previously showed that estrogen has beneficial effects on cardiovascular function via the novel G‐protein coupled estrogen receptor (GPER). Selectively activating GPER may elicit beneficial cardiovascular effects of estrogen without eliciting deleterious effects. Receptor expression is important in developing targeted pharmacological therapies, but the regulation and expression of estrogen receptors is still not fully understood.

Objective

Our goal was to study the effects androgens, glucocorticoids, and progesterone on the expression of the classical estrogen receptor ERα and novel estrogen receptor GPER.

Methods

Mouse aortic smooth muscle cells (MOVAS) were grown in 10% FBS media to 80% confluency and then starved for 24 h in charcoal‐stripped 0.5% FBS. The plates were treated for 24 h with 100 nm of dexamethasone (DEX), dihydrotestosterone (DHT), medroxyprogesterone acetate (MPA), or vehicle. After treatment, RNA was extracted and droplet digital PCR was used to quantify the expression of both GPER and ERα. Results were analyzed using a one‐way ANOVA.

Results

GPER expression was decreased by both DHT (66% of control, p=0.006, n=9) and MPA (70% of control, p=0.012, n=6). The impact of DEX on GPER was not statistically significant (89% of control, p=0.245, n=9). ERα expression was significantly reduced by DEX (65% of control, p=0.0046, n=9), DHT (56% of control, p=0.004, n=9), and MPA (52% of control, p=0.005, n=6) as compared to controls.

Conclusions

In cultured vascular smooth muscle cells, DHT and MPA decreased the expression GPER, while DEX, DHT, and MPA downregulated ERα. These results suggest that androgens, glucocorticoids, and progesterone act at the transcriptional level to decrease the expression of GPER and ERα. This decrease in receptor expression could lessen beneficial effects of GPER and/or ERα on cardiovascular function. Future studies will address the impact of androgens, glucocorticoids, and progesterone on the molecular mechanisms and in vivo cardiovascular responses to estrogen. The regulation of estrogen receptor expression is important for understanding the clinical interactions that may alter the response to hormone therapy.

Support or Funding Information

Funding was provided by NIH HL133619 to SHL.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
The Effects of Sex Differences and Diet on the Development of Non‐Alcoholic Fatty Liver Disease in SAMP8 Mice
Authors: Altenburg Haylee M. , Kamm Dakota R. , Schaller Megan L. , Harris Matthew P. , Witt Ken A. , Sandoval Karin E. , Wooten Joshua S.
Published: June 2021

Non‐alcoholic fatty liver disease (NAFLD) has become the leading form of chronic liver disease and has been associated with increased risk for non‐alcoholic steatohepatitis (NASH) and hepatocellular carcinoma. Western diets, high in both saturated fats and fructose, have been associated with hepatic lipotoxicity, however, little is known about sex‐related differences in the progression of NAFLD. Therefore, the purpose of this study was to determine the effects of sex‐ and diet‐related differences on the development of NAFLD in a senescence‐accelerated mouse model. At 12 weeks of age, Senescence Accelerated Mouse‐Prone 8 (SAMP8) mice were divided by sex and randomly assigned to either a standard diet (SD; 10% kcal fat) or a Western diet (WD; 45% kcal fat and 24% kcal fructose) for 9 months. Hepatic tissue was analyzed for total lipid, triglyceride, and cholesterol levels. A two‐way (sex × diet) ANOVA was used to identify sex‐ and diet‐differences with statistical significance set at p<0.05. A diet effect was observed where the consumption of a WD resulted in elevated total lipid (9.25 ± 3.4% vs. 4.03 ± 1.0%), hepatic triglyceride (24.8 ± 13.9 μg/mg vs. 1.2 ± 0.9 μg/mg), and hepatic cholesterol (2.6 ± 1.7 μg/mg vs. 0.5 ± 0.1 μg/mg) when compared to SD. A sex effect was observed with male mice having higher total lipid (7.70 ± 0.4% vs. 5.98 ± 0.4%), hepatic triglyceride (16.1 ± 1.9 μg/mg vs. 10.9 ± 1.8 μg/mg), and hepatic cholesterol (2.0 ± 0.2 μg/mg vs. 1.2 ± 0.2 μg/mg) than the female mice. The interaction between sex and diet revealed no difference between male and female mice for SD, however, male mice displayed greater hepatic total lipid, triglyceride, and cholesterol levels than female mice fed the WD. In summary, consumption of a Western diet in male mice resulted in a greater progression of fatty liver disease than female mice in a senescence‐accelerated mouse model.

Support or Funding Information

Supported by NIH R21NS090282‐01.

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
DNA methylation as a mediator of the association between stress and depression: A genome‐wide DNA methylation study
Authors: Su Shaoyong , Hao Guang , Youssef Nagy Adel , Stefanek Michael , Treiber Frank , Wang Xiaoling , Pollock Jennifer , Harshfield Gregory
Published: June 2021

Background

Stressful events can increase the risk of developing depression, but the underlying mechanism is unclear. The purpose of this study is to examine whether DNA methylation may mediate the association between stress exposure and depression.

Methods

Participants from the Georgia Stress and Heart (GSH) study were assessed for perceived stress and childhood adversity with the Perceived Stress Scale (PPS) and Adverse Childhood Experience (ACE) questionnaire including the assessment of childhood abuse, neglect, and household dysfunction. Experienced stress was defined as PPS score≥22 (top tertile of PPS score) and ACEs≥3 in this study. The Beck Depression Inventory (BDI) was used to assess depressive symptoms. Genome‐wide DNA methylation in peripheral leukocytes was analyzed using Illumina 450K Bead‐Chip.

Results

There were 329 participants (mean age: 28±3 years) eligible for analysis in our study. After adjustment of age, sex, race, body mass index and smoking status, those who experienced both childhood and current stress had significantly higher BDI score compared to those with no stress exposure (17.3±11.3 vs. 4.5±5.2, P<0.001). A total of 5 CpG sites showed differential methylation levels in the stress group at the threshold of genome‐wide significance (false discovery rate, FDR<0.05). Out of these 5 CpG sites, one CpG site (cg16962045, the closest gene is GPR162) was associated with both stress and depression (P<0.001). Mediation analysis revealed that the relationship between stress and depression was partially mediated by cg16962045, in which 8.9% (95%CI: 7.0–12.2) of the correlation could be explained by the methylation of cg16962045 (P=0.039).

Conclusion

Novel findings of the present study identified that DNA methylation at the GPR162 gene could partially mediate the relationship between stress and depression, suggesting that epigenetic modifications play a role in the underlying mechanisms in response to chronic stress and contribute to the development of mental disorders.

Support or Funding Information

The present study was supported by NIH P01HL69999; R01HL125577

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Extreme Physiology ‐ The Ultimate Outdoor Classroom
Authors: Sweeney Terrence E. , Hamilton‐Fay Tara N.
Published: June 2021

We have created Extreme Physiology, a 300‐level travel course in exercise and environmental physiology that takes advantage of stunning and diverse outdoor environments and a community learning paradigm to greatly facilitate student learning of complex physiological phenomenon. Ten students and two faculty members from The University of Scranton spend 25 days of their January intersession in Arizona. The course is based for 2 1/2 weeks in Tucson, split up by an intervening week at 7000 feet elevation in Flagstaff. It employs the course's students and its faculty as both subjects and investigators. Utilizing University of Arizona facilities and in collaboration with Arizona faculty, baseline human performance data, including maximal oxygen consumption, peak anaerobic performance, blood lactate, hematocrit, hemoglobin and resting ventilatory measurements are collected on all students and faculty, with followup measurements as the course progresses and the environment changes. Following the collection of baseline data, students and faculty engage in a three‐week exercise regimen of road and mountain biking, running, hiking and swimming. Exercise is performed in the breathtaking landscapes of Arizona previously unknown to the students, including two national parks, enabling exposure to a broad array of environmental milieus, providing challenging terrain, and increasing the novelty of the student experience. A community living arrangement that includes the students and their instructors enables introduction of nutritional concepts to the course, as students and faculty prepare meals together throughout the course. Continuous access to the course faculty further extends the learning environment, as students learn critical concepts in exercise and environmental physiology, present and discuss primary literature articles directed at course content, and collect, analyze and present their own human performance data.

Support or Funding Information

Supported by The University of Scranton. The authors gratefully acknowledge their collaboration with Physiology and Nursing faculty of the University of Arizona

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.