bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondrial Transcription Factor A & Cardiac Stability
Authors: Kunkel George H. , Theilen Nicholas , Jeremic Nevena , Weber Gregory , Tyagi Suresh C. 
Published: November 2023

Heart failure is a functional lack of myocardial performance due to a loss of molecular control over increases in calcium and ROS, resulting in proteolytic degradative advances and cardiac remodeling. Mitochondria are the molecular powerhouse of cells, shifting the sphere of cardiomyocyte stability and performance. Functional mitochondria rely on the molecular abilities of safety factors such as TFAM to maintain physiological parameters. Mitochondrial transcription factor A (TFAM) creates a mitochondrial nucleoid structure around mtDNA, protecting it from mutation, inhibiting NFAT (ROS activator/hypertrophic stimulator), and transcriptionally activating Serca2a to decrease calcium mishandling. Current literature depicts major decreases in TFAM as HF progresses. We aim to assess TFAM function against Calpain 1 and MMP 9 proteolytic activity and its role in cardiac remodeling. To this date, no publication has surfaced describing the effects of aortic banding (AB) as a surgical heart failure model in TFAM‐TG mice. HF models were created via AB in TFAM Transgenic (TFAM‐TG) and C57BLJ‐6 (control) mice. Eight weeks post‐AB, functional and histological analysis revealed a successful banding procedure, resulting in cardiac hypertrophy as observed via echocardiography. Pulse wave and color doppler show increased aortic flow rates as well as turbulent flow at the banding site. Preliminary results of cardiac tissue immuno‐histochemistry of HF‐control mice show decreased TFAM and compensatory increases in Serca2a fluorescent expression, along with increased calpain 1 and MMP9 expression. Protein, RNA, and IHC analysis will further assess TFAM‐TG results post‐banding. Echocardiography show more cardiac stability and functionality in HF induced TFAM‐TG mice than the control counterpart. These preliminary findings, along with our invitro results, suggest that TFAM has molecular therapeutic potential to reduce protease activity.Support or Funding InformationThe study is supported by NIH Grants HL‐74185 and HL‐108621 to SCT and NIH F31 Grant 1F31HL132527‐01 to GHK
Unraveling the Identity of Active Serine Proteases in Inflammatory Bowel Diseases
Authors: Vergnolle Nathalie , Deraison Celine , Chrystelle Bonnard , Edir Anissa , Gilmore Brendan , Quaranta Muriel , Sebert Morgane , Alric Laurent , Bonnet Delphine , Bunnett Nigel , Souza Alexandre Denadai 
Published: November 2023

IntroductionOur team recently revealed that an upregulation in proteolytic activity is a central mechanism in the pathophysiology of Inflammatory Bowel Disease (IBD), such as Crohn's disease (CD) and ulcerative colitis (UC). Otherwise, the identity of proteases underlying this process remains elusive.ObjectiveIdentify active serine proteases in the colonic mucosa of IBD patients by using Activity‐Based Probes (ABP).Material and MethodsSamples of colonic mucosa supernatants or tissue extracts were incubated with biotinylated ABPs designed to form covalent complexes with active serine proteases. ABP‐serine proteases complexes were then submitted to SDS‐PAGE to generate ABP proteomic profiles and LC‐MS/MS analysis to identify the active proteases.ResultsABP proteomic profiles revealed that active proteases clustered in 4 main groups with mean MW of 27.8, 32.6, 35.4 and 71.5 kDa. Compared to control patients, there was a trend of upregulation for proteases with mean MW of 27.8 and 32.6 kDa in CD and UC, whereas a protease with 71.5 kDa was detected exclusively in UC. Preliminary LC‐MS/MS analysis of IBD samples identified up to 13 potential serine proteases (i.e. PRSS1/2, TPSAB1, DLD, PREP, etc) and 8 proteases from other clans (i.e. LTA4H, PARK7, etc).ConclusionThe present study identified proteases not yet described as expressed in the colonic mucosa, as well as proteases derived from genes associated to IBD risk loci with unknown function in the gastrointestinal tract. This data will direct further studies aiming at establishing the relevance of these proteases in the pathophysiology of IBD.Support or Funding InformationAgence Nationale de la Recherche (ANR) and European Research Council (ERC).
Osteocytes orchestrate mechanical signal transduction in bone via WNT
Authors: Robling Alexander 
Published: November 2023

Mechanical loading is essential to maintain normal bone metabolism and the balance between bone formation and resorption. The cellular mechanisms that control bone cell mechanotransduction are not fully understood, but several key pathways have been identified in osteocytes. One such mechanism involves Wnt signaling—a pathway involved in many physiologic processes including body axis specification/patterning, and morphogenic signaling. The first clues of WNT's role in bone biology began with several genetic studies that sought to identify the cause of Osteoporosis Pseudoglioma (OPPG), an autosomal recessive disease characterized by early‐onset osteoporosis and blindness. Mutant mouse studies revealed that loss‐of‐function mutation in the WNT co‐receptor LDL‐Receptor‐related Protein 5 (Lrp5) caused OPPG, but perhaps more importantly, that osteocytic Wnt signaling through Lrp5 is crucial for load‐induced bone formation. Moreover, mechanical loading strongly regulates Sost/sclerostin expression—a potent inhibitor of Wnt/Lrp5 signaling. Sost, and its protein product sclerostin, are nearly exclusive to the osteocytes—the cell postulated to be the tissue's sensor apparatus in transducing mechanical loading events. The suppression of sclerostin expression by mechanical loading may provide a mechanism by which Wnt signaling is enhanced and bone formation is enacted. Furthermore, Wnt signaling modulation via Sost/sclerostin also appears to modulate the process of disuse osteoporosis. As the mechanisms of mechanical signal transduction in osteocytes become revealed, a greater range of targetable molecules will be manifest, that might ultimately be exploited to improve bone health among patients with a wide range of skeletal disease.Support or Funding InformationNIH R01 AR053237VA I01 BX001478
Cardiovascular adaptations to moderate anemia maintain cerebral perfusion but are inadequate to prevent renal and splanchnic tissue hypoxia
Authors: Mistry Nikhil , Solish Max , Cahill Lindsay , Zhou Yu‐Qing , Hare Alexander GM , Doctor Allan , Lazarus Alan H , Sled John G , Mazer C David , Hare Gregory MT 
Published: November 2023

Mild to moderate anemia is associated with increased organ injury and mortality in surgical patients by undefined mechanisms. We hypothesize that anemia‐induced tissue hypoxia is a potential unifying mechanism. A transgenic mouse model, with luciferase fused to hypoxia inducible factor (HIF ODD‐Luciferase) was utilized to assess the impact of acute antibody‐mediated anemia on adaptive cardiovascular responses, tissue PO2 (PtO2), and HIF expression. A red blood cell (RBC)‐specific antibody (TER119) induced anemia, reducing hemoglobin concentrations from 144±9 to 94±11 g/L (p<0.006) via intravascular hemolysis and RBC sequestration in the spleen and liver. Anemia‐induced cardiovascular adaptations included: 1) increased peripheral arterial oxygen saturation (p=0.018); 2) increased cardiac output (26%, p=0.011); 3) increased internal carotid blood flow (80%, p<0.001); and 4) augmented cerebrovascular reactivity relative to control mice (p<0.001). All of these mechanisms contributed to the maintenance of brain PtO2 (Control vs. Anemia: 23±10 vs.23±5 mmHg O2, p=0.935). By contrast, no increase in renal blood flow occurred (p=0.239), and kidney PtO2 decreased in anemic mice (21±4 vs. 13±4 mmHg O2, p<0.001). Molecular adaptations to tissue hypoxia included increased HIF‐1α expression within the dorsal renal and hepatic region (30%, p=0.006), and ventral gut region (72%, p=0.017). These findings demonstrate anemia‐induced tissue hypoxia is heterogeneous and organ‐specific and support the hypothesis that renal and splanchnic hypoxia may contribute to increased organ injury and mortality in anemic perioperative patients.Support or Funding InformationThe project described was supported by the St. Michael's Hospital AHSC AFP Innovation Fund Grant Support
Comparison of the Ventilatory Responses Elicited by Hypoxic Gas Challenge in Freely‐Moving C57BL6 and A/J Male Mice
Authors: Coffee Gregory A , Getsy Paulina Marie , Lewis Stephen J 
Published: November 2023

Genetic differences in humans determine the propensity for disordered breathing including the incidence and severity of sleep apneic events. We have reported that the C57BL6 mouse strain displays a robust series of responses to hypoxic gas challeges.1 Considering evidence that the A/J strain of mouse may be less prone to non‐eupneic breathing,2 our objective was to compare the ventilatory responses elicited by hypoxic challenge in adult male freely‐moving C57BL6 and A/J mice.Mice were placed in whole‐body plethysmography chambers and subjected to episodes of hypoxic (10% O2, 90% N2) gas challenges (5 episodes of 5 min in duration separated by 15 min). Ventilatory parameters included, frequency of breathing, tidal volume, minute ventilation (= frequency × tidal volume), inspiratory and expiratory times, end inspiratory and expiratory pauses, peak inspiratory and expiratory flows, EF50 (expiratory flow at 50% expired tidal volume) and central inspiratory drive (tidal volume/inspiratory time).With respect to baseline values, frequency was lower whereas tidal volume was higher in the A/J than the C57BL6 mice such that the minute ventilation was similar in A/J and C57BL6 mice. Inspiratory and expiratory times were both longer in A/J mice than in C57BL6 mice. The remaining parameters including, end inspiratory and expiratory pauses, peak inspiratory and expiratory flows, EF50 and central inspiratory drive were similar in the two mouse strains.With respect to the ventilatory responses elicited by hypoxic challenges, there were relatively minor differences between C57BL6 and A/J mice in most of the studied parameters. The key differences were that expiratory times and end expiratory pauses dramatically increased upon return to room‐air following the hypoxic gas challenges in C57BL6 mice whereas these values simply returned to baseline in A/J mice.This study demonstrates that key differences exist between C57BL6 and A/J mice in baseline values and responses to hypoxic gas challenges. Longer duration post‐hypoxia expiratory times and end expiratory pauses are a hall‐mark of humans with sleep apnea. As such, the dramatic increase in these parameters in the post‐hypoxic challenge phases in C57BL6 mice and their absence in A/J mice provide an avenue to further understand the genetic make up of sleep disordered breathing.Support or Funding InformationGlaxoSmithKline (GSK) Funding CWRU Internal Number: RES510692
Glucagon‐like peptide‐1 affects mean arterial pressure, renal blood flow and urinary flow rate in spontaneously hypertensive rats despite no renal expression of GLP‐1 receptors
Authors: Sorensen Charlotte Mehlin , Ronn Jonas , Holst Jens Juul , Jensen Elisa Pauline 
Published: November 2023

Glucagon‐like peptide‐1 (GLP‐1) has many extrapancreatic effects and the GLP‐1 receptor is expressed in many tissues. GLP‐1 increases renal blood flow (RBF), glomerular filtration rate and sodium and water excretion. Also, GLP‐1 has been shown to reduce blood pressure in some hypertensive models. The aim of this study was to examine expression of the GLP‐1 receptor in the renal vasculature from spontaneously hypertensive rats (SHR) and to assess the renal and vascular effects of GLP‐1.MethodsThe GLP‐1 receptor was localized using both immunohistochemical staining and in situ hybridization for the GLP‐1 receptor on kidney sections from normotensive Sprague‐Dawley (SD) and hypertensive SHR rats. The vasodilatory effect of GLP‐1 was examined in isolated interlobar arteries. In vivo experiments were performed on rats monitoring mean arterial blood pressure (MAP), RBF, heart rate (HR), urine flow and sodium excretion. GLP‐1 was infused directly into the kidney for 20 min before and after infusion of the GLP‐1 receptor antagonist exendin9–39.ResultsNo GLP‐1 receptor positive staining was found in kidneys from SHR whereas there was GLP‐1 receptor positive staining in the vascular smooth muscle cells in the renal vasculature from normotensive rats. No vasodilation was elicited in interlobar arteries from SHR whereas arteries from SD responded to increasing concentrations of GLP‐1. Intrarenal infusion of GLP‐1 increased BP, RBF, urine flow and sodium excretion significantly in both rat strains whereas heart rate was unchanged. The effect on RBF and MAP was abolished by exendin9–39 whereas the increase in urine flow and sodium excretion was still present.ConclusionThe renal effects of GLP‐1 in SHR do not rely on the presence of renal GLP‐1 receptors. It seems likely that the GLP‐1 mediated effects in SHR are mediated via extrarenal GLP‐1 receptors e.g. GLP‐1 receptors in organs responsible for regulation of insulin or ANP.
The choroid plexus sodium‐bicarbonate cotransporter NBCe2 regulates cerebrospinal fluid pH
Authors: Barbuskaite Dagne , Praetorius Jeppe , Christensen Henriette L , Rojek Alexandra , Nielsen Hans Malte , Fuchtbauer Ernst‐Martin , Wang Tobias , Damkier Helle Hasager 
Published: November 2023

Respiratory centers in the central nervous system (CNS) react to changes in pCO2 and maintain systemic acid/base homeostasis by controlling the rate and depth of respiration. Both blood‐brain barrier and blood‐CSF barrier are highly permeable to CO2 enabling swift transmission of arterial pCO2 fluctuations to be coupled with CSF pH changes, whilst both barriers are much less permeable to H+and HCO3−, hence masking the effects of metabolic acid‐base disturbances. The electrogenic Na+‐HCO3−cotransporter NBCe2 is expressed in the CSF‐facing plasma membrane of the choroid plexus epithelial (CPE) cells and could be a regulator of CSF pH. We hypothesized that NBCe2 is responsible for HCO−extrusion into the ventricle lumen to counteract decreases in CSF pH during acidosis. Intracellular pH (pHi) measurements on CPE cells from NBCe2 knockout (KO) mice showed a statistically significant 84% increase in Na+‐dependent acid extrusion following intracellular acidification by ammonium chloride prepulse and an 81% reduction in DIDS‐sensitive base efflux after intracellular alkalization by trimethylamine. Knockout of NBCe2 abolished CSF pH recovery from hypercapnia‐induced acidosis compared to control mice: wt (n=5): 0.0048 ± 0.003 vs ko (n=6): −0.0001±0.0002 pH units/min, p=0.0043. Choroid plexus targeted NBCe2 knockdown mice generated by intracerebroventricular installation of siRNA revealed a similar effect: Control (n=5): 0.002+/−0.0004 vs. NBCe2 knockdown (n=7): −0.0001±0.0007, p=0.047. Knockout of NBCe2 did not affect respiration rate or tidal volume compared to wildtype, and revealed a similar ventilatory response as controls when exposed to 5% CO2. In conclusion, we show that NBCe2 is important for recovery of CSF pH after CO2 induced acidosis by transporting HCO3−into the CSF. This suggests a significant role for NBCe2 in regulating brain pH when faced with an acid challenge independent of the respiratory response.Support or Funding InformationDagne Barbuskaite is funded by a PhD stipend from the Faculty of Health and Medical Sciences and the department of Cellular and Molecular Medicine, Copenhagen University. Henriette L. Christensen is funded by a PhD stipend from the Faculty of Health, Aarhus University.The project is financed by the Danish Council for Independent Research/Medical sciences and the Laege Sofus Carl Emil Friis og Olga Doris Friis' legat.
H,K‐ATPase type 2 participates in the adaptive proliferation of quiescent renal A‐type intercalated cells in response to K+ depletion
Authors: Crambert Gilles , Cheval Lydie , Doucet Alain , Edwards Aurélie , Walter Christine 
Published: November 2023

Quiescent renal epithelial cells proliferate in response to specific stimuli such as K+depletion or metabolic acidosis, leading to hypertrophy of the kidney. The role of ion transporters in cell proliferation is now well established: intracellular pH and intracellular K+ and Cl− concentrations are key determinants of cell volume and thereby contribute to cell division. Interestingly, H,K‐ATPase type 2 (HKA2) has recently been shown to participate in cell proliferation in a leukemia cell model and its expression is dysregulated in different cancers (3, 4). HKA2 could interfere with cell proliferation by transporting H+ and/or K+. Taking into account the fact that this transporter is strongly up‐regulated in A‐type intercalated cells (A‐IC) of the collecting duct (CD) in response to K+ depletion (for review see (1)), we investigated whether it participates in the cell proliferation process that occurs under these conditions.In contrast to WT mice under a low‐K+ diet, HKA2‐null mice (HKA2‐KO) did not exhibit an increased number of either total or proliferative A‐IC. However, K+ depletion increased the expression of early proliferation markers such as PCNA and cyclin D1 similarly in WT and HKA2‐KO. These results indicate that in the absence of HKA2, the process of A‐IC proliferation is initiated but is promptly aborted. This is confirmed by the fact that the number of apoptotic (TUNEL‐positive) cells in the CD of HKA2‐KO mice is 3 times higher than in that of WT after K+ depletion. According to our recent mathematical model of ion transport in the CD (2), the absence of HKA2 may result in a lower A‐IC cell volume (−20%). Therefore, HKA2 may be relevant during K+ depletion by contributing to the cell swelling process required during cell division. A dysfunctional increase in cell volume during cell proliferation may result in the activation of ER stress mechanisms and indeed, under a low K+ diet, CHOP expression is almost twice as high in HKA2‐HO mice relative to WT mice.Altogether, these results revealed a new role for the renal H,K‐ATPase type 2 that may participate in the process of cell proliferation in the context of K+ depletion.Support or Funding InformationThis study was supported by recurrent grants from the Institut National de la Santé et de la Recherche Médicale (INSERM) and from the Centre National de la Recherche Scientifique (CNRS)
Select Moringa oleifera Subfractions Exhibit Potent Antibacterial Properties against Escherichia coli
Authors: Orders Tanner , Nair Srijith , Smith Brandon , Slate Jamison , Moreano Noah , Oyugi Emelda , Reinker Sam , Salih Yahya , Maisura Ravi , Payne Aubryana , Emrani Jahangir , Idassi Joshua , Frank Martin , Mowa Chishimba Nathan 
Published: November 2023

Bacterial infection is one of the leading causes of preterm labor and use of pharmaceuticals is not ideal during pregnancy for teratogenic reasons. In an effort to provide safer antibacterial treatments, we have previously used whole‐leaf extracts of Moringa oleifera (MO) to screen the antibacterial efficacy of whole‐leaf extracts isolated using various solvents against Escherichia coli (E. coli), a leading cause of urinary tract infections associated with preterm labor. These earlier studies found the ethanolic whole‐leaf extract to be the most potent. Here, we test the antibacterial effects of eight high performance liquid chromatography (HPLC)‐isolated ethanolic‐based leaf subfractions of M. oleifera. In the initial experiments we screened each subfraction using diffusion assays and later the more potent subfractions (numbers four, five and six) were further tested using in vitro liquid broth assays and were found to act in a dose‐dependent manner. Although all the eight subfractions exerted some antibacterial effect at a concentration of 20 μg or less, only the three subfractions cited earlier had significant activity and subfraction number five showed the most antibacterial effect at 20 μg and required the least concentration for the lethal dose fifty (LD50) and minimal bactericidal concentration. Subfraction number five was followed by four and then six in potency. We conclude that the anti‐bacterial activity of whole leaf M. oleifera is likely exerted by subfractions number five, four and six. Ongoing studies in our lab are testing the potential synergistic effects of the different subfractions.Support or Funding InformationOSR, Appalachian State University
Oxygen glucose deprivation modulates endothelial Ca2+ signal mediated by TRPV4‐KCa channels
Authors: Lin Mike T , Choi Chung‐Sik , Zha Xiangming , Yap Fui Chi 
Published: November 2023

Endothelial blood brain barrier maintenance and breakdown depend on Ca2+ magnitude and spatiotemporal dynamics. We have shown that activation of endothelial TRPV4‐KCa (transient receptor potential vanilloid 4‐calcium‐activated potassium) channels' positive feedback results in microvascular permeability increase and vasogenic edema in a Ca2+‐dependent manner. Mouse cerebral endothelial cells express two types of KCa channels—SK3 (small KCa type 3) and IK1 (intermediate KCa) channels. Both SK3 and TRPV4 channels reside at caveolae presumably via interaction with caveolar scaffolding protein, caveolin‐1. IK1 channels, however, do not reside at caveolae, suggesting differential TRPV4 Ca2+ signaling microdomains associated with SK3 and IK1 channels. In this study, we tested whether ischemia/reperfusion modulates TRPV4‐KCa microdomain Ca2+ signals. Our results showed that the Ca2+ signals mediated by TRPV4‐SK3 differed from that mediated by TRPV4‐IK1 channels' positive feedback. SK3‐associated Ca2+ events showed large amplitude with slow decay kinetic. These events were infrequent compared to that associated with IK1 channels; IK‐associated Ca2+ events had small amplitude and fast decay kinetics. In response to 60 min of oxygen glucose deprivation (OGD), Ca2+ events shifted predominately toward that resembling IK1‐associated (frequent Ca2+ events, small amplitude and fast kinetic). GSK (GSK1016790A, a selective TRPV4 channel agonist; 10 nM) increased Ca2+ event site and amplitude before OGD; however, after OGD the Ca2+ signals induced by GSK became Ca2+ wave‐like events. It is known that low [Ca2+] confined to microdomains maintains junctional protein complexes, whereas large and repetitive Ca2+ waves induced by ischemia/reperfusion enhance blood brain barrier leakage. Taken together, our results suggest that the Ca2+ dynamics underlying TRPV4‐KCa channels' positive feedback may play an important role in blood brain barrier integrity modulation.Support or Funding InformationSupported by HL102056 (Lin) and S10 0D020149 (MS Taylor, University of South Alabama).