bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcriptional regulation and therapeutic targeting of P2X7 receptors in diabetic nephropathy
Authors: Menzies Robert I , Booth John W , Mullins John J , Bailey Matthew A , Tam Frederick W , Norman Jill T , Unwin Robert J 
Published: November 2023

Purine P2X7 receptors are essential components of pro‐inflammatory signalling, functionally expressed on multiple immune and non‐immune cells. Renal biopsies from patients with diabetic nephropathy show widespread, glomerular mesangial expansion, immune cell infiltration and fibrosis. Here we show that in diabetic patients, renal P2X7 expression is associated with severe mesangial expansion, impaired glomerular filtration (≥40ml/min), and increased fibrosis (50%+) compared with non‐diabetic controls. P2rx7‐deficient mice developed STZ‐induced hyperglycaemia similar to controls but had reduced glomerular macrophage attraction and collagen IV deposition. Activation of P2X7 was investigated in a rat model of diabetic nephropathy. Wister rats underwent uninephrectomy and STZ‐induction. Whole kidney P2rx7 mRNA expression was increased (2.2‐fold; P<0.05) compared with sham controls by 8 weeks of induction. Glomerular and interstitial macrophage accrual increased, reflecting the pathology seen in patient biopsies. Rats were then randomly selected to receive drug vehicle or selective P2X7R antagonist (AZ11657312; 50mg/kg IP) twice daily for the following 4‐weeks. P2X7R antagonism supressed transcription of pro‐inflammatory signalling molecules compared with the vehicle group, and reduced interstitial macrophage accrual. These data suggest that P2rx7 contributes to renal inflammation in diabetics and P2X7R antagonists may have therapeutic potential.Support or Funding InformationRIM is a BHF Immediate Postdoctoral Basic Science Research Fellow (Award number FS/15/60/31510). JWRB received a MRC/Kidney Research UK Joint Clinical Training Fellowship (Award number G0901956). We would like to thank GSK for gifting the P2X7k expressing gene‐targeted mice. FWKT is supported by the Diamond Fund from Imperial College Healthcare Charity. Part of this work is supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Imperial College Healthcare NHS Trust and Imperial College London.
Suppression of Albumin‐Induced Matrix Metalloproteinase‐9 by Rosiglitazone in Renal Tubular Epithelial Cells
Authors: Cobbs Alyssa , Chen Xiaoming , Khamdy Anjulyna , Chima Ashmeer , George Jasmine , Zhao Xueying 
Published: November 2023

Matrix metalloproteinase‐9 (MMP‐9) activation is closely linked to albuminuria in chronic kidney disease. This study was designed to explore the role of albumin on MMP‐9 expression and activity in renal tubular epithelial cells (TECs). The effect of rosiglitazone, a PPARγ agonist, on MMP‐9 activation was further examined in the diabetic kidneys and in vitro primary cultured TECs. In vivo, in situ zymography and immunostaining revealed an increase in gelatinase activity and MMP‐9 protein in the damaged tubules of Zucker diabetic rats. Increased tubular MMP‐9 staining was mainly observed in the tubules expressing kidney injury molecule‐1 (KIM‐1) in the diabetic kidneys. Additionally, urinary excretion of MMP‐9 was associated with an increase in urinary albumin in untreated diabetic rats. Chronic administration of rosiglitazone led to a downregulation of KIM‐1 and osteopontin genes in the diabetic kidneys. Moreover, urinary albumin and MMP‐9 protein were significantly decreased in rosiglitazone‐treated diabetic rats. To evaluate the effect of albumin on expression and activity of MMP‐9, primary cultured rat TECs were incubated with rat serum albumin (RSA, 0.1 – 0.5 mg/ml) for 24 – 48 hrs. RSA administration resulted in a dose‐dependent increase in MMP‐9 protein and activity in culture supernatants of TECs. Rosiglitazone pretreatment significantly attenuated albumin‐induced MMP‐9 expression and secretion from TECs. Taken together, these results suggest that albuminuria may accelerate kidney disease progression by activating tubular MMP‐9. The renoprotective effects exerted by rosiglitazone may be attributed partially to its suppression of albumin‐induced MMP‐9 activity in diabetic kidney disease.Support or Funding InformationThis work is supported by the NIH SDK096441, 1SC1DK112151, 8G12MD007602 and 8U54MD007588.
Modeling the Effects of Functional Adaptation to Reduction in Renal Mass
Authors: Layton Anita , Edwards Aurelie , Vallon Volker 
Published: November 2023

When kidney tissue is removed or damaged, the remaining nephrons undergo compensatory growth and adaptive functional changes. The objective of this study is to assess the impact of such structural and functional adaptation. To do so, we developed computational models of solute transport along different nephron populations of a uninephrectomized and a 5/6‐nephrectomized rat kidney. The model represents detailed epithelial and paracellular transport processes along both the superficial and juxtamedullary nephrons. The loop of Henle of each model nephron extends to differing depths of the inner medulla. Each nephron segment is represented as a rigid tubule lined by a layer of epithelial cells, with apical and basolateral transporters that vary according to cell type. To simulate a uninephrectomized or 5/6‐nephrectomized kidney, we reduced the nephron population, increased single‐nephron glomerular filtration rate, and increased nephron size based on data in the literature. Model simulations were conducted to determine what tubular transport changes are necessary to preserve baseline salt excretion. Model results also revealed the differing degrees to which salt transport and oxygen consumption are changed along the different nephron segments.Support or Funding InformationThis research was supported in part by NIH grant DK‐106102.
Neuronal nitric oxide synthase inhibits store‐operated Ca2+ entry in cardiomyocytes via S‐nitrosylation of stromal interaction molecule‐1
Authors: Feng Qingping , Gui Le , Zhu Jinhui , Lu Xiangru , Sims Stephen M. , Lu Wei‐Yang , Stathopulos Peter B. 
Published: November 2023

Store‐operated Ca2+ entry (SOCE) mediated by stromal interacting molecule‐1 (STIM1) and Orai1 represents a major route of Ca2+ entry in mammalian cells. The luminal domain of STIM1 is critical to Ca2+ sensing, STIM1 oligomerization and SOCE activation. Notably, the luminal domain contains two cysteine sites (Cys49 and Cys56). It is not known if neuronal nitric oxide synthase (nNOS), which is associated to the sarcoplasmic reticulum (SR) membrane, regulates STIM1 oligomerization and SOCE activity in cardiomyocytes via S‐nitrosylation of these cysteine sites. Here, we show that nNOS deficiency or treatment with a nNOS inhibitor L‐VNIO significantly increased SOCE in cardiomyocytes. Further, the Ca2+ release‐activated Ca2+ channel current (ICRAC) was significantly enhanced in cardiomyocytes treated with L‐VNIO and in nNOS−/− cardiomyocytes. Consistently, STIM1 S‐nitrosylation was significantly decreased in nNOS−/− hearts. Treatment of HEK293 cells co‐expressing YFP‐Orai1 and mCherry‐STIM1 with the NO donor S‐nitrosoglutathione (GSNO) inhibited STIM1 puncta formation and ICRAC. Remarkably, no functional inhibition was observed in cells expressing the Cys49Ser/Cys56Ser STIM1 double mutant. Mechanistically, we found that NO donors caused Cys49 and Cys56‐specific structural changes associated with reduced protein backbone mobility, significantly increased the thermal stability and suppressed Ca2+‐depletion‐dependent oligomerization of the luminal Ca2+‐sensing region of STIM1. Collectively, our data reveal that nNOS inhibits SOCE in cardiomyocytes through NO‐mediated STIM1 S‐nitrosylation which suppresses oligomerization via enhanced luminal domain stability and rigidity.Support or Funding InformationCanadian Institutes of Health Research
Hydrogen peroxide inhibits neurons in the paraventricular nucleus of the hypothalamus
Authors: Kline David D. , Matott Michael P. 
Published: November 2023

The paraventricular nucleus (PVN) of the hypothalamus is an important center for neuroendocrine, respiratory and autonomic regulation. The PVN has reciprocal innervation with the nucleus tractus solitarii (nTS) and both are activated by exposure to low oxygen (hypoxia). Hypoxia induces increased reactive oxygen species (ROS) production. Previously we've shown in the nTS that the ROS hydrogen peroxide (H2O2) hyperpolarized membrane potential and reduced action potential discharge via an increase in potassium conductance that operates at the resting potential. The goal of this study was to examine the electrophysiological effect of H2O2 on PVN parvocellular neurons. Anesthetized Sprague‐Dawley rats were rapidly decapitated and the cortex removed and blocked to make 300 μm acute PVN slices. PVN neurons were recorded at 32 °C in whole cell patch clamp mode and exposed to 150 μM H2O2 (5 min) in artificial cerebrospinal fluid (aCSF). H2O2 induced a significant positive (outward) current of 71 ± 50.5 pA when neurons were held at −60 mV. Peroxide also significantly decreased spontaneous excitatory post‐synaptic current (sEPSC) frequency by 3 ± 1 Hz but did not change sEPSC amplitude. In some neurons inhibitory post‐synaptic currents (IPSCs) became evident after H2O2. Peroxide significantly decreased outward potassium currents (IK) across voltage steps between +10 and +40 mV. Under current clamp, peroxide hyperpolarized membrane potential by −21 ± 6 mV and decreased action potential discharge (APD), evoked by a depolarizing ramp, from 13 ± 3 APs to 2 ± 1 APs. All of these electrophysiological properties except for APD and IK were reversed by wash with aCSF. These data indicate that H2O2 alters pre‐ and postsynaptic properties of PVN neurons to likely alter cardiorespiratory reflexes.Support or Funding InformationHL098602
Correlation of ventricular arrhythmogenesis with neuronal remodeling in cardiac postganglionic parasympathetic neurons during the progression of heart failure after myocardial infarction
Authors: Zhang Dongze , Tu Huiyin , Wang Chaojun , Muelleman Robert L , Wadman Michael , Li Yu‐Long 
Published: November 2023

Lethal ventricular arrhythmia has been a major cause of sudden cardiac death in patients with chronic heart failure (CHF). Autonomic dysfunction has been defined as a negative prognostic indicator for high mortality associated with lethal ventricular arrhythmia during the progression of CHF. Our previous study has demonstrated that expression and ion currents of N‐type Ca2+ channels in cardiac postganglionic parasympathetic (CPP) neurons located in intracardiac ganglia (ICG) are decreased in late stage of CHF rats. However, it is unclear whether electrical remodeling in CPP neurons contributes to ventricular arrhythmogenesis during the development of CHF. Here, we investigated relationship between ventricular arrhythmogenesis and neuronal remodeling in CPP neurons in coronary arterial ligation‐induced CHF rats. ECG data obtained from continuous telemetry recording in conscious rats showed that ventricular tachycardia/fibrillation (VT/VF) occurred in 1–3 and 12–14 weeks after coronary arterial ligation (60 % and 80%, respectively), whereas VT/VF did not occurred in 6–8 weeks after coronary arterial ligation. Additionally, as an index of ventricular vagal tone, the change of left ventricular pressure in response to vagal efferent nerve stimulation was blunted in 12 –14 weeks but not 1–3 weeks or 6–8 weeks after coronary arterial ligation. More importantly, the results from whole‐cell patch clamp recording demonstrated that N‐type Ca2+ currents in CPP neurons began to decrease in 6–8 weeks after coronary arterial ligation, and had a significant decrease in 12–14 weeks after coronary arterial ligation. Based on above results, we concluded that lethal ventricular arrhythmia mainly occurred in both early stage and late stage of CHF after myocardial infarction. Electrical remodeling in CPP neurons highly correlated with the occurrence of fatal ventricular arrhythmia in late stage of CHF. However, lethal ventricular arrhythmia in early stage of CHF was not attributed to N‐type Ca2+ currents in CPP neurons. These new findings suggest that improving ventricular vagal tone at late stage of CHF might be a potential therapeutic target for prevention of fatal ventricular arrhythmia and sudden cardiac death in patients with CHF.Support or Funding InformationThis study was supported by AHA Grant‐in‐Aid (15GRANT24970002)
Effect of Cortisol on Growth and Gene Expression of insulin‐like growth‐factor binding proteins (igfbps) in Atlantic Salmon Parr
Authors: Springer‐Miller Ryan , Chenoweth Damaris , Paskavitz Amanda , Regish Amy , McCormick Stephen , Breves Jason 
Published: November 2023

Growth performance of teleost fishes, including salmonids, is principally controlled by the growth hormone (Gh)/insulin‐like growth‐factor (Igf) axis. Igfs interact with cognate binding proteins, termed Igf binding proteins (Igfbps), which modulate the biological activities of Igfs. While Atlantic salmon (Salmo salar) are known to express an expansive set of igfbp transcripts in several key metabolic tissues, the actual regulators of igfbp expression have not been identified. Given the well‐documented consequences of mounting a glucocorticoid stress response on growth, we hypothesized that cortisol inhibits anabolic processes by directing the dynamic expression of igfbps. We therefore examined changes in the activities of the Gh/Igf/Igfbp network of salmon parr implanted with cortisol (0, 10 and 40 μg/g body weight) and sampled after 3 or 14 days. We observed reductions in body mass and fork length following 3‐ and 14‐day treatments with cortisol at 40 μg/g. A dose dependent reduction in growth rate occurred by 14 days of treatment with cortisol, whereas hepatosomatic index was not affected. We will report igfbp transcript levels in liver, skeletal muscle and gill with an aim to resolve how activities within the Igfbp network are modulated by cortisol in juvenile Atlantic salmon.Support or Funding InformationSupported by Start‐Up funds to J.P.B.
Use of mTOR as a potential molecular marker to investigate the development of obesity in non‐model fish species
Authors: Spainhour Rebekah , Ball Jenna , Kobayashi Yass 
Published: November 2023

Objectives of this study were to identify the genes encoding mechanistic target of rapamycin (mTOR) in channel catfish and examine their tissue distribution. mTOR plays a key role in the regulation of protein synthesis, cell growth, cell proliferation, and nutrient metabolism. Therefore, functions of mTOR have been investigated in association with obesity and diabetes development. In channel catfish, genetic selection toward growth causes the development of obese‐like phenotype, which suggests that channel catfish can serve as an alternative model to investigate obesity and diabetes development. However, little is known about the role of mTOR in channel catfish. Genes encoding mTOR were identified by screening the channel catfish genome database. The expression of various mTOR mRNA was examined in the cDNA of brain, spleen, trunk kidney, liver, Brockmann body and muscle tissues using RT‐PCR. With the exception of the brain, mTOR mRNA expression was detectable in all tissues examined at varied degree. The nucleotide sequence of amplicon corresponding mTOR (480 bp) was highly similar to those of other fish (>80%), as well as that of mice (>78%), and humans (>79%). Currently, we are investigating changes in expression of mTOR mRNA in relation to changes in food intake and genetic selection toward growth in channel catfish.Support or Funding InformationSupported by the Kansas IDeA Network of Biomedical Research Excellence (P20GM103418).
Brief Exposure to Intermittent Hypoxia Prolongs QTc in Human Subjects, which is Abrogated with AT1a Receptor Blockade.
Authors: Jouett Noah , Bysani Kaethan , Cooley Daniel , Cutler Michael , Raven Peter , Smith Michael 
Published: November 2023

Patients with Obstructive Sleep Apnea (OSA) frequently succumb to sudden cardiac death (SCD). Prolongation of the QTc, possibly via intermittent hypoxia (IH) mediated activation of angiotensin II type 1a receptors (ATR1a), predisposes towards SCD. Hence, the present study tested the hypothesis that (1) a brief exposure of IH lengthens QTc which (2) is abrogated with Losartan, an antagonist of ATR1a. Further, we evaluated how Losartan affects the relationship between direct measurements of muscle SNA (MSNA) and QTc via linear regression analyses during IH. Seven healthy human subjects were recruited with normal 12‐lead ECGs. Subjects ingested either placebo or 100 mg of Losartan 1 hour prior to experimentation, and then repeated the study on a separate day in a randomized, repeated measures design. 3‐lead ECG and MSNA (peroneal microneurography) were recorded throughout the study. Subjects were exposed to 20 minutes of IH, which was composed of 20 cycles of the following: 2–3 breaths of 95–100% N2, 20‐second end‐expiratory apnea, and 40‐second room‐air recovery. QTc (determined by Bazett's formula) averages were compared statistically using a repeated‐measures ANOVA. Losartan did not alter baseline QTc (P = 0.17). IH + Placebo significantly prolonged QTc (baseline: 359.8 ± 4.8 ms vs. IH: 368.3 ± 4.8 ms, P < 0.001). Losartan abrogated the IH‐mediated QTc prolongation (baseline: 364.5 ± 5.7 ms vs. IH: 367 ± 6.4 ms, P = 0.11). Furthermore, changes in MSNA explained only 6% of the variance in QTc during IH with Placebo, which increased to 22% with IH and Losartan (IH + Placebo: R2 = 0.06, IH + Losartan: R2: 0.22). In conclusion, IH prolongs QTc, which is prevented with Losartan . Furthermore, IH alters the relationship of MSNA and QTc, in part through activation of ATR1a. Future studies should evaluate the possible cardioprotective benefits of ATR1a antagonists in OSA patients.Support or Funding InformationNone
Renal denervation lowers mean arterial pressure in obese female Schlager mice but adversely affects glucose metabolism
Authors: Asirvatham‐Jeyaraj Ninitha , Banek Christopher T , Gauthier Madeline M , Han Ruijun , Razzoli Maria , Bartolomucci Alessandro , Panoskaltsis‐Mortari Angela , Osborn John W 
Published: November 2023

Clinical studies have shown that, in addition to lowering arterial pressure (AP), renal denervation (RDNx) improves glucose metabolism in drug‐resistant hypertensive obese patients. One‐fourth of these patients were females. We have observed a similar arterial pressure response in preliminary studies in obese genetically hypertensive male Schlager mice (BPH/2J). Although sex differences may exist regarding RDNx therapy, the effect of RDNx on AP and glucose metabolism in females specifically has not previously been studied. We hypothesized that, similar to males, RDNx will decrease AP and improve glucose metabolism in high fat fed female Schlager mice. 8‐week old mice were fed either a low fat diet (LFD; 10 KCal% from fat) or high fat diet (HFD; 45 KCal% from fat) for 10 weeks. Fasting blood glucose were measured on week 11 of the protocol. Radiotelemeters were implanted in the femoral artery on week 12 of the protocol for measurement of ambulatory AP. Body weight, food intake, body‐composition and glucose metabolism were measured throughout the study. After measuring baseline AP, LFD and HFD groups were then divided into RDNx or Sham treatment and followed for 14 days. After 10 weeks of diet, HFD versus LFD fed mice had increased body weight (30±1 vs. 26±1, g) and fasting blood glucose (83±3 vs. 68±4, mg/dL). HFD increased the baseline AP (124±4 mmHg) compared to LFD mice (112±4 mmHg). RDNx normalized AP in HFD mice (107±3) but had no effect on AP in LFD mice (106±4). Compared to sham treated mice, RDNx had no effect on fasting blood glucose or the glucose tolerance in LFD mice. In contrast to our hypothesis, fasting blood glucose was higher in RDNx‐HFD (76±3) compared to Sham‐HFD (69±4) mice. Similarly, the area under the curve for the glucose tolerance test was higher in RDNx‐HFD (555 ± 51) compared to Sham‐HFD (426 ± 24) mice. We conclude that RDNx effectively lowers AP in obese genetically hypertensive female Schlager mice, but also results in adverse effects on glucose metabolism. The mechanisms mediating these responses are currently underway and identifying these mechanisms could help develop targeted therapies for obese hypertensive females by clearly avoiding the adverse effects.Support or Funding InformationNHLBI R01 HL116476
Development of Tools for RNA interference (RNAi) of the engrailed Gene in Daphnia magna
Authors: Singer Davi , Beckman Matt 
Published: November 2023

The legend of the cyclops has been a part of international folklore for centuries. Yet, we do not fully understand the developmental genetic basis for cyclopia. Daphnia magna, a water flea, is a naturally occurring cyclops which can serve as a model to study this phenomenon. In this study tools were created to examine the role of the engrailed gene in Daphnia eye development. In Drosophila melanogaster (fruit flies), silencing of the engrailed gene affects segmentation during early development. Additional studies suggest that engrailed is one candidate gene involved in eye field development. To understand the role of engrailed in Daphnia development, we sought to knockdown the gene's expression using RNA interference (RNAi). Using the online databases Uniprot and the wFleaBase we acquired the D. magna hedgehog mRNA sequence. Using this sequence we designed primers to amplify portions of the D. magna engrailed gene. Engrailed gene PCR products were then cloned into the pGC‐Blue vector. Work continues to clone the engrailed insert into the RNAi feeding vector L4440. The L4440 plasmid will be transformed into HT115 E.coli and fed to Daphnia. Future work will also include qPCR studies of the engrailed gene expression during key time‐points in Daphnia eye development and following RNAi knockdown. In summary, through this work tools are being developed to study the role of engrailed in cyclopean eye development. We believe that by leveraging in our studies, Daphnia magna, a true cyclopean organism that evolution built, we can gain a deeper understanding of the developmental genetic basis for midline disorders.Support or Funding InformationWe thank the Augsburg Biology Department, Augsburg McNair Program and the Augsburg LSAMP STEM program for supporting this work.