bluuebunny/crossref_metadata_2025_split huggingface dataset:
Downregulation of intestinal sodium/glucose cotransporter‐1 is mediated by the short form of the leptin receptor (Ob‐Ra) (893.32)
Authors: Dominguez Rieg Jessica , Mahata Sushil , Köpsell Hermann , Rieg Timo 
Published: June 2021

We have shown that intestinal SGLT1 is decreased in leptin receptor (long form; Ob‐Rb) deficient mice. To determine if SGLT1 is regulated by leptin itself, we utilized Ob‐Rb deficient mice with compensatory increased leptin levels (db/db; n=6), leptin deficient mice (ob/ob; n=5), and their controls (db/con and ob/con, n=10 and 6, respectively). Db/db and ob/ob mice were obese (46±1 vs 27±2 g and 46±1 vs 25±1 g, respectively; P<0.01) and hyperglycemic (532±24 vs 120±4 mg/dl and 315±34 vs 168±9 mg/dl, respectively; P<0.01) vs controls. While Western blot and immunofluorescence revealed decreased apical membrane expression of SGLT1 in db/db mice vs db/con (44%±10 vs 100%±8; P<0.01), ob/ob mice had no change in membrane abundance. In contrast to the long form, the short form of leptin receptor (Ob‐Ra) is fully functional in db/db mice. To determine if leptin‐mediated downregulation of SGLT1 is mediated by Ob‐Ra, db/db (n=4) and db/con (n=5) were treated with the Ob‐Ra antagonist catestatin, a 20 amino acid fragment of chromogranin A (5 µg/g bw/day). After 6 days, blood glucose levels rose higher in db/db vs db/con mice (Δ change: 232±51 vs 50±12 mg/dl; P<0.05), which corresponded to a marked increase in SGLT1 membrane abundance via immunofluorescence in both groups. In conclusion, leptin signaling mediated by Ob‐Ra suppresses intestinal SGLT1 abundance, which may prevent exacerbated hyperglycemia in db/db mice.Grant Funding Source: Supported by P30DK079337, 5I01BX000323 and 10SDG2610034
Hyperglycemia‐increased activity of blood‐brain barrier Na‐K‐Cl cotransport and Na/H exchange involves SGK1 and PKCβII (893.35)
Authors: Chechneva Olga , Klug Nicholas , Yuen Natalie , O'Donnell Martha 
Published: June 2021

Hyperglycemia (HG) exacerbates cerebral edema and worsens ischemic stroke outcome although the mechanisms are unclear. We have shown that ischemic factor stimulation of blood‐brain barrier (BBB) Na‐K‐Cl cotransport (NKCC) and Na/H exchange (NHE) increases secretion of Na and water into the brain, promoting cerebral edema formation. We recently found that HG (30 mM glucose; 6, 24,48 hr and 7 d) increases cerebral microvascular endothelial cell (CMEC) NKCC and NHE abundance and activity and augments ischemic factor‐stimulated transporter activity. Serum‐glucocorticoid kinase 1 (SGK1) and protein kinase CβII (PKCβII) have been implicated in the pathogenesis of HG. Thus, here we examined whether SGK1 and PKCβII are involved in HG effects on BBB NKCC and NHE using cultured CMEC and Western blot, radioisotopic flux and microspectrofluorometry methods. HG (24 or 48 hr) significantly increased expression and activation of CMEC SGK1 and PKCβII. Inhibition of SGK1 or PKCβII with GSK650394 (10 μM) and CGP53353 (1 μM) respectively, reduced or abolished HG‐increased NKCC and NHE activity. In these studies we also found that HG (24 hr) significantly increased astrocyte NKCC activity in a manner reduced by SGK1 and PKCβII inhibitors. Our findings support the hypothesis that HG exacerbation of cerebral edema in ischemic stroke involves SGK1 and PKCβII‐induced increases in BBB and astrocyte Na transporter activities.Grant Funding Source: Supported by NIH and ADA
Nox2‐derived superoxide does not contribute to oxidative stress‐induced vascular upregulation of T‐type channel function (893.6)
Authors: Hill Caryl , Matthaei Klaus , Drummond Grant , Howitt Lauren 
Published: June 2021

Cardiovascular disease is characterised by reduced nitric oxide (NO) and increased oxidative stress. We have shown that these conditions increase the expression and contribution of T‐type channels to vascular tone through increased bioavailability of reactive oxygen species produced from NADPH oxidase (Nox). As Nox2‐generated superoxide has been causally implicated in several vascular disease models, we investigated whether Nox2 was also responsible for upregulation of T‐type channel function in cremaster arterioles in vivo, using wildtype (WT) and Nox2‐deficient mice (Nox2KO). We first validated a novel T‐type channel antagonist, TTA‐A2 (3µM; provided by Merck and Co, Inc) which demonstrated no cross reactivity with L‐type channel function in these arterioles. In both WT and Nox2KO mice, acute inhibition of NO with L‐NAME (10µM) significantly increased the T‐type contribution to vascular tone. Chronic L‐NAME treatment (40mg/kg/day) for 2 weeks significantly increased blood pressure of both WT and Nox2KO mice, as well as the T‐type channel component of arteriolar tone. Pharmacological inhibition of Nox1 (10µM ML171) and Nox4 (10µM VAS2870) together reversed the effect of chronic L‐NAME on T‐type channel function in Nox2KO mice. We conclude that Nox2‐generated superoxide is not responsible for the upregulation of T‐type calcium channels elicited by oxidative stress.Grant Funding Source: Supported by the Heart Foundation of Australia
Computational modeling of MRP4 and BSEP substrates and inhibitors (896.10)
Authors: Swaan Peter , Köck Kathleen , Welch Matthew , Urban Thomas , Brouwer Kim 
Published: June 2021

Drug‐induced liver injury (DILI) is an important cause of drug toxicity. Inhibition of MRP4, in addition to BSEP, might be a risk factor that is responsible for the development of cholestatic DILI. Recently, we demonstrated that MRP4 inhibition was associated with an increased cholestatic potential of drugs that are BSEP non‐inhibitors, while MRP4 inhibition among BSEP inhibitors did not provide additional benefit to predict cholestasis. The current study aimed to develop in silico models to delineate molecular features underlying MRP4 and BSEP inhibition.Models were developed using 257 BSEP and 88 MRP4 inhibitors and non‐inhibitors in the training set based on various molecular descriptors as well as fingerprints (ECFP and FCFP). Models were validated using an external test set; subsequently, these models were used to predict the affinity towards BSEP and MRP4 of a database (CDD) containing over 2,200 FDA‐approved drugs. Compounds with a score above the median fingerprint threshold were considered to have significant inhibitory effects on MRP4 and BSEP. Common feature pharmacophore models were developed with the Catalyst software suite using a training set of 20 well‐characterized MRP4 substrates and inhibitors.For MRP4 substrates and inhibitors, common feature pharmacophore models were characterized by hydrogen‐bond acceptor and donor features as possible interaction forces between MRP4 ligands and the transporter protein. Models were further used to predict over 70 potential MRP4/BSEP inhibitors by integrating hits retrieved from the CDD database with a list of 208 compounds known to cause DILI.The Bayesian (BSEP, MRP4) and pharmacophore (MRP4) models demonstrated significant classification accuracy and predictability. Potential novel MRP4 inhibitors were predicted by virtual screening of the database based on Bayesian and pharmacophore models. Subsequent in vitro testing should further our knowledge on MRP4 and BSEP affinity and their role in DILI.Grant Funding Source: NIH R01GM041935, R01DK61425, T32‐ES007126, and Deutsche Forschungsgemeinschaft Ko4185/1‐1
Identification and molecular characterization of 5′‐regulatory region of the human SLC52A1 (rft‐1) promoter (896.4)
Authors: Sabui Subrata , Said Hamid 
Published: June 2021

The human SLC52A1 gene encodes riboflavin transporter‐1 (rft‐1) which is essential for riboflavin transport across cell membranes. Rft‐1 is strongly expressed in human placenta, small intestine, heart muscle and thymus. Nothing is known about the transcriptional regulation of the human SLC52A1. We addressed the issue by cloning the 5'‐regulatory region of the SLC52A1 gene, identified the minimal promoter region for basal activity and identified potential cis‐regulatory elements. Guided by Rapid amplification of the cDNA ends (5'‐RACE), evidence was obtained for existence of one transcription start site (TSS) at nt‐716 in intestinal epithelial cells (Caco‐2). A 384‐bp segment upstream of the TSS was found to exhibit significant promoter activity in different human derived intestinal epithelial cells (Caco‐2, HuTu80 and NCM460). Truncation of this segment revealed that core promoter activity was embedded in a 297‐bp fragment (‐146 to +149) that contains GC rich, lacks TATA element and harbors several putative transcription factor binding sites includes SP‐1, AP‐2 and NFkB. Mutating the latter sites resulted in a significant decrease in promoter activity suggesting involvement of these cis‐regulatory elements in the regulation of SLC52A1 transcription. This study reports on first characterization of the SLC52A1 promoter.Grant Funding Source: Supported by the VA and NIH, DK56061
Systemic Porphyromonas gingivalis lipopolysaccharide exacerbates the inflammatory response post‐myocardial infarction through matrix metalloproteinase‐9 (897.6)
Authors: DeLeon‐Pennell Kristine , de Castro Bras Lisandra , Bratton Dustine , Linsey Merry 
Published: June 2021

Why periodontal disease (PD) strongly correlates with increased mortality post‐myocardial infarction (MI) is unknown. Previously, we showed P. gingivalis‐lipopolysaccharide (PgLPS) exposure increases matrix metalloproteinase (MMP)‐9 in the left ventricle (LV) of wild‐type (WT) mice. Because MMP‐9 plays a critical role post‐MI, we hypothesized that circulating PgLPS would exacerbate the LV inflammatory response post‐MI through MMP‐9. We compared WT and MMP‐9 null mice (3‐7 months old; n=12 survivors/group) infused with either PgLPS (0.08 µg/g/day) or saline for 28 days before and throughout the duration of MI. PgLPS increased rupture rate (rupture/total deaths) in WT (7/7) compared to saline controls (6/15) and was attenuated in Null (1/2). Echocardiography showed LV wall thinning increased at d7 post‐MI in WT (0.61±0.05 mm) compared to d0 (0.84±0.03 mm; p˂0.05). This effect was amplified by PgLPS in WT (0.44±0.04 mm) and attenuated in Null (0.50±0.04 mm; p˂0.05 for both). Plasma proteomics showed MMP‐9, macrophage inflammatory protein‐1β, ‐1γ, monocyte chemotactic protein‐1, and ‐3 increased in WT post‐MI and intensified by PgLPS suggesting amplified inflammatory response. This effect was attenuated by MMP‐9 deletion. In conclusion, circulating PgLPS exacerbates LV inflammation post‐MI through a MMP‐9 mechanism, resulting in a greater extent of LV dysfunction.Grant Funding Source: Supported by AHA POST14350034; HHSN 268201000036C; R01HL075360; VA 5I01BX000505; HL051971
Hydrogen sulfide protects from colitis: a possible role in stabilizing gut microbiota (898.3)
Authors: Motta Jean‐Paul , Flannigan Kyle , Agbor Terence , Blackler Rory , Workentine Matt , Da Silva Gabriela , Buret Andre , Wallace John 
Published: June 2021

We hypothesised that hydrogen sulfide (H2S) modifies gut microbiota and resolves intestinal inflammation. Rats were gavaged with diallyl disulfide (DADs), and colitis was induced by dinitrobenzene sulfonic acid (DNBS). Colitis severity was assessed by macroscopical, biochemical, and histological analysis. Microbial genetic diversity was performed by denaturing gradient gel electrophoresis. Antimicrobial activity of DADs, NaHS and Na2S was evaluated by plating and growth assays. Human intestinal epithelial cell lines were used to assess expression levels of antimicrobial peptides by qRT‐PCR, western‐blotting and immunofluorescence.Administration of DADs increased the expression of cathelicidin, separated the microbiota from the host by a thick mucus barrier, and slightly altered microbial genetic diversity. Treatment of DNBS animals with an inhibitor of H2S‐producing enzyme provoked a more severe colitis, enhanced the presence of mucosa‐associated microbial aggregates, and altered mucus barrier. These inflammatory parameters were all reduced when DNBS‐treated animals were given DADs. In vitro, H2S‐releasing compounds inhibited the growth of four strains of gut bacteria. Additionally, H2S altered the level of expression of cathelicidin and trefoil factor‐3 in human epithelial cells.The findings shed a new light on the therapeutic potential of H2S delivery during the course of colitis.Grant Funding Source: Izaak Walton Killam PDF fellowship / University of Calgary Eye's High PDF fellowship
Notch signaling regulates proliferation and differentiation in the adult mouse intestine (899.4)
Authors: Zayan Nichole , Carulli Alexis , Samuelson Linda 
Published: June 2021

Human gastrointestinal tumors can exhibit increased Notch signaling; accordingly, intestinal Notch over‐activation was examined in genetic mouse models ubiquitously expressing the Notch intracellular domain (NICD) in the intestinal epithelium. Based on previous studies, we hypothesized that Notch over‐activation would induce increased proliferation, decreased secretory cells, and increased absorptive cell numbers. NICD expression was activated in bitransgenic mice (Villin‐CreERT2 ; Rosa‐FSF‐NICD‐nGFP) by 5 daily doses of tamoxifen with intestine collected on day 6. We found that epithelial proliferation was increased and the goblet cell population was decreased in the NICD intestine. However, contrary to our hypothesis, the alkaline phosphatase‐positive enterocyte population appeared decreased, which was confirmed by reduced mRNA levels of the enterocyte marker sucrase‐isomaltase. Based on these data, we concluded that Notch over‐activation increases proliferation and decreases all differentiated cell types, not just secretory cells. This finding suggests that constitutive Notch activation in the intestine leads to a hyperproliferative state, consistent with activation of this pathway in human tumors.Grant Funding Source: Supported by APS Fellowship (NEZ) and NIH grants R01‐DK078927 (LCS) and F30‐DK095517 (AJC).
The pathogenic role of poly(ADP‐ribose) polymerase 1 in experimental colitis (902.11)
Authors: Larmonier Claire , Shehab Kareem , McFadden Rita‐Marie , Hill Faihza , Alizadeh Darya , Thurston Robert , Ghishan Fayez , Kiela Pawel 
Published: June 2021

Poly(ADP‐ribose) polymerases (PARPs), including its most abundant isoform PARP1, catalyzes the transfer of ADP‐ribose units from NAD+ to a number of target proteins. In vivo studies have demonstrated that genetic ablation or pharmacological inhibition of PARP1 ameliorates experimental colitis pathophysiological changes. However, the studies have failed to characterize the mechanism by which PARP1 inhibition is protective in colitis. We evaluated the effect of PARP1 deletion in T cell‐mediated colitis in the following scenarios: adoptive naïve CD4+CD45RBHigh T cell transfer from WT or Parp1‐/‐ mice into Rag2‐/‐ and Rag2‐/‐ x Parp1‐/‐ DKO mice and DSS‐induced colitis in WT, Parp1‐/‐, Rag2‐/‐, and Parp1‐/‐Rag2‐/‐ DKO mice. Compared to WT mice, Parp1‐/‐ mice were protected from DSS‐induced colitis. However, WT and Parp1‐/‐naïve T cells were equally colitogenic in Rag2‐/‐ recipients. DKO mice transferred with WT T cells or treated with DSS showed only marginal improvement. Our preliminary data indicate that Parp1 is dispensable in naïve and effector T‐cells, while Parp1‐/‐ mice are protected from colitis resulting from DSS‐induced epithelial damage. Moreover, the lack of significant protection in T cell transfer or DSS models of colitis in DKO mice suggests a pathogenic role of Parp1 in the innate immune cells and regulatory T cells during colitis.Grant Funding Source: NIH Grant 1K01DK099268‐01
Zinc recovers altered intestinial ion‐transport and barrier function caused by Shigella infection in T84 cells (902.9)
Authors: Kazi Mirajul , Paramita Sarkar , Sheikh Irshad , Chakraborty Subhra 
Published: June 2021

Zinc (Zn) has been shown to improve diarrhea. However, mechanism linking Zn to improve inflammatory diarrhea caused by Shigella sp. is not known. We tested that Zn restore paracellular and transcellular ion transport by modulating tight junction protein expression and chloride secretion, altered by Shigella infection. Human colonic epithelial cells, T84 were grown onto transwell inserts for measurements of permeability to dextrans, transepithelial electrical resistance (TER), short‐circuit current (Isc), and dilution potential (DP) in Ussing chamber. Cells infected with Shigella flexneri 2a caused reduction of TER by 40%, DP [4 ± 1.2 vs. 1.5 ± 0.3 mV] which was prevented in presence of Zn. An increase in paracellular flux of 4kDa dextran [2.1± 0.6 vs. 0.8 ± 0.2 µg/3.5hr/cm2] with respect to 70kDa was evident while in the presence of Zn, flux of 4kDa dextran was reversed by 52%. Immunofluorescence study revealed removal of claudin 1 and 2 from tight junction complex correlated with the loss of TER and paracellular flux. Studies with Ussing chambers demonstrated reduced cAMP stimulated electrogenic ion transport in infected cells. Zn application prevented this effect. Our results suggest that in T84 cells, Shigella infection caused (1) altered barrier function (2) altered Cl secretion. Zn application reversed these transport functions. These conclude that Zn may have beneficial role in inflammatory diarrhea.Grant Funding Source: Supported by Dept. of Biotechnology, Govt. of India
The effect of wheat products on the colonization of the microbiota in the intestines of zebrafish (903.2)
Authors: Savarese Mary , Tousignant K. Davis , Uno Jennifer 
Published: June 2021

Celiac disease is sensitivity to the wheat protein, gluten, characterized by intestinal inflammation and villous atrophy of the small intestine in genetically susceptible individuals. Inducing factors of celiac disease include ingestion of gluten, antibiotic exposure, infections, and a dysbiosis of the microbiota. Zebrafish have emerged as a viable model to study gastrointestinal diseases; however, they have yet to be used to directly study celiac disease. The aim of this work was to assess the potential use of zebrafish as a model for studying celiac disease. Fish were placed on a wheat‐based or brine fish regime. Antibiotics were used to knock‐down the microbiota in order to examine the reestablishment of the gut flora. All fish intestines were pooled into groups of 3, bacterial DNA was isolated and primers were used to amplify the 16S gene of specific bacterial groups. Bacterial levels were calculated as a percentage relative to total 16 S bacteria. Results show no significant difference in total bacterial expression however there was a significant decrease in Bifidobacterium (n=3, p< 0.05) in the wheat fed relative to the brine shrimp fed fish. These results confirm current studies indicating decreased expression of Bifidobacterium in bacterial DNA isolated from celiac patients. These data indicate the potential use of zebrafish to further the understanding of gut inflammation associated with wheat allergies.Grant Funding Source: Supported by Elon University
The effects of Rosmarinus officinalis L. aqueous extracts on gastric acid secretion in isolated rats stomach (904.4)
Authors: Celebi Fikret , Gelen Volkan , Cınar Dursun , Sengul Emin 
Published: June 2021

The Effects of Rosmarinus officinalis L. Aqueous Extracts on Gastric Acid Secretion in Isolated Rats Stomach.Volkan Gelen, Emin Sengül, Fikret Çelebi, D.Ali Cınar.Department of Physiology, Faculty of Veterinary Medicine, University of Atatürk, Erzurum, Turkey Rosmarinus officinalis L. (Rosemary) has been shown to have antioxidant, anti‐inflammatory and antiulces activites in different conditions.The present work was performed to investigate the possible effects of rosemary aqueous extracts on gastric acid secretion in isolated rats stomach.The stomachs of adult male Sprague‐Dawley rats were removed.The stomach was placed in a 20‐ml organ bath containing a serosal nutrient solution.Gastric acid secretion was measured from mucosal content in the isolated rat stomach.The results obtained in vitro experiments showed that doses of 300 µg/ml, 600 µg/ml and 1200 µg/ml of rosemary aqueous extracts have increased basal gastric acid secretion (except, 150 µg/ml).The present results suggest that rosemary may has a relieving effect on indigestion, probably due to increasing basal gastric acid secretion.
HFE deficiency attenuates impulsivity induced by intranasal manganese (907.7)
Authors: Ye Qi , Kim Jonghan 
Published: June 2021

HFE deficiency attenuates impulsivity induced by intranasal manganese Qi Ye and Jonghan Kim Department of Pharmaceutical Sciences, Northeastern University, Boston, MA, USA While excessive manganese (Mn) alters emotion and mood, olfactory Mn transport is enhanced in Hfe deficiency, which is the major cause of iron overload hemochromatosis. Hence we investigated the effect of HFE on Mn‐related impulsivity using Hfe‐knockout (Hfe‐/‐) and wild‐type (Hfe+/+) mice after intranasal instillation of MnCl2 (5 mg/kg) daily for 3 wks. Mn‐instilled mice spent more time in open arms than water‐instilled mice in an elevated plus maze, indicating an increased impulsivity (p=0.024, n=10‐13). Upon Mn exposure, however, Hfe‐/‐ mice entered the open arm later than Hfe+/+ mice (p=0.008), indicating that Mn‐induced impulsivity was corrected by Hfe deficiency. Since dopamine transporter (DAT) in the prefrontal cortex is involved in impulsivity, we conducted western blot and found that Mn instillation increased DAT levels in Hfe+/+ mice (1.3‐fold increase; p=0.004) but not in Hfe‐/‐ mice. To further investigate if oxidative stress induced by metal exposure is associated with altered emotion, activities of superoxide dismutase (SOD), an anti‐oxidative enzyme, was evaluated. SOD activity was elevated in Hfe‐/‐ mice(p<0.001), but reduced in Hfe+/+ mice (p=0.046) upon Mn exposure. Taken together, our results suggest that individuals with HFE deficiency could be less susceptible to airborne Mn‐induced impulsivity, likely due to altered dopamine signaling and enhanced protective activity of SOD.Grant Funding Source: NIH R00 ES017781
GIP regulates glucose transporer‐2 to augment jejunal glucose absorption in obese mouse prior to the onset of diabetes (908.5)
Authors: Coon Steven , Rajendran Vazhaikkurichi , Singh Satish 
Published: June 2021

Background: Jejunal glucose absorption is mediated by apical SGLT1 in normal‐, and by GLUT2 in obese mice. GIP, an incretin hormone, activates SGLT1 in normal mice. Aim: To determine if GIP regulates glucose absorption via GLUT2 in the obese jejunum. Methods: Short circuit current (Isc, a measure of SGLT1 activity) and glucose flux (measure of SGLT1 &amp; GLUT2) were obtained under voltage clamp conditions at 0, 1, 2 and 5 mo in jejunums from mice fed a high‐fat diet. Results: In obese mice, GIP significantly activated SGLT1‐mediated glucose absorption for up to 2 mos, but was drastically decreased by 5 mos (2 vs. 5 mos = 725 vs. 49 µA/cm2). In contrast, the rate of GIP‐activated glucose absorption was steadily increased for up to 5 mos on a high‐fat diet (2 vs. 5 mos = 1.4 vs. 2.3 µEq/h.cm2). Western‐blot analyses of biotinylated proteins revealed that GIP exposure enhanced GLUT2 expression in apical membranes of jejunum at 5 mos. Conclusions: GIP both activates and recruits sub‐apical GLUT2 to apical membranes to augment glucose absorption in the jejunum of obese mice.Grant Funding Source: Supported by NIH CTSI grant number UL1TR000157