bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell cholesterol levels determine glucose uptake and insulin resistance in skeletal muscle
Authors: Llanos Paola , Contreras-Ferrat Ariel , Osorio-Fuentealba Cesar , Espinosa Alejandra , Hidalgo Cecilia , Jaimovich Enrique 
Published: June 2021

In skeletal muscle, cholesterol is enriched in the transverse tubule membranes (TT), where insulin‐promoted GLUT4 translocation occurs. To test the role of TT cholesterol content, we fed mice a high fat diet (HFD) and measured insulin triggered glucose uptake. Cholesterol levels were measured in TT‐enriched triad fractions isolated from skeletal muscle of male C57BL/6J mice fed either a normal or a HFD (60% fat) for 8 weeks. Isolated muscle fibers from flexor digitorum brevis were used for fluorescence glucose uptake determinations. Akt activity in myotubes was determined by Western blot analysis. Relative to controls, body weight, body fat content and metabolic variables including insulin resistance were higher in HFD fed mice. Cholesterol levels in triads from HFD‐fed mice were 30% higher than in controls. Preincubation of myotubes with Methyl‐β‐cyclodextrin to remove cholesterol partially inhibited Akt phosphorylation in controls, and increased both basal and insulin‐induced glucose uptake in muscle fibers from controls or HFD‐fed mice. Cholesterol removal restored insulin sensitivity in HFD‐fed mice, independently of Akt and CaMKII inhibition. Our findings indicate that cholesterol removal from muscle fibers may be a strategy for improving insulin resistance in HFD‐fed mice and suggest that TT cholesterol has a physiological role in glucose transport.FONDECYT 3110105, FONDAP 15010006.
Glycosomal localization of dihydroxyacetone phosphate acyltransferase LmDAT is important for lipophosphoglycan biosynthesis
Authors: Patel Nipul , Zhu Tongtong , Dhalladoo Subbhalakshmi , Zufferey Rachel 
Published: June 2021

Protozoan parasites of the genus Leishmania are the causative agents of several human and animal diseases collectively called leishmaniases. The parasite cycles between an insect vector the sand fly, and mammalian host's macrophages. Cell‐surface components protect the parasite from the host immune system and constitute virulence factors. Ether glycerolipids are a significant part of the parasite's membranes and ether glycerolipid based macromolecules are also important virulence factors. Thus, enzymes involved in synthesis of ether lipids in Leshmania may represent a drug target for control of the disease. In L. major, a glycosomal dihydroxyacetonephosphate acyltransferase, LmDAT, initiates the ether lipid biosynthetic pathway. We demonstrated that an active LmDAT is critical for normal growth and survival of the parasite during stationary phase. Deletion of the N‐terminal amino acid residues of the enzyme reveals that this domain may be important for proper folding of the enzyme and hence for its activity. Abrogation of its C‐terminal glycosomal targeting sequence leads to its extraglycosomal localization. However, this mislocalization does not affect its enzymatic activity but alters the synthesis of the ether‐lipid based virulence factor, lipophosphopglycan, demonstrating that glycosomal subcellular localization is critical for the production of ether‐lipids.This work was funded by American Heart Association.
Is the eukaryotic cis‐prenyltransferase a heteromer? The role of NgBR and its yeast ortholog Nus1 in protein glycosylation
Authors: Grabinska Kariona A , Guan Ziqiang , Sessa William C 
Published: June 2021

Dolichyl phosphate (Dol‐P) serves as an obligate lipid carrier in different type of protein glycosylations. Dol‐P precursor ‐ polyprenyl pyrophosphate ‐ is synthesized by a cis‐prenyltransferase (cisPTase) activity. Recently we have shown that NgBR is as an essential component of the Dol‐P biosynthetic machinery. Loss of NgBR results in deficit of cisPTase activity, leading to diminished levels of dolichol‐linked oligosaccharides and a reduction in protein N‐glycosylation. NgBR interacts with the previously identified cisPTase hCIT, enhances hCIT protein stability, and promotes Dol‐P synthesis. Inactivation of yeast ortholog of NgBR, Nus1 gives lethal phenotype and causes N‐glycosylation defect. In this work we confirmed that shutting down expression of NUS1 results in N‐glycosylation defect and demonstrated that this phenotype is related to loss of cisPTase activity and dolichol synthesis. Glycosylation‐dependent phenotypes are complemented by expression of bacterial type undecaprenyl pyrophosphate synthase. We hypothesize that active eukaryotic cisPTase is not a homodimer as crystallized bacterial enzyme but heteromer consisting of: NgBR and hCIT in humans or Nus1 and Rer2 in ER and Nus1 and Srt1 in lipids bodies of yeast S. cerevisiae. Reconstitution of active eukaryotic cisPTase is in progress.This work was supported by grant R01HL081190 from the NIH to WCS
Activation of angiotensin type 2 receptor rescues high‐fat dietinduced adipocyte size increase in young male mice
Authors: Nag Sourashish , Khan Mohammed Azhar , Hussain Tahir 
Published: June 2021

Recent studies demonstrated that genetic deletion of angiotensin type 2 receptor (AT2R) decreases adipocyte size and controls obesity, a major risk factor for metabolic syndromes. Current study was designed to test whether pharmacological manipulation of AT2R regulates adipocyte size. Male C57BL/6 mice (4‐weeks old) were pretreated with AT2R antagonist (PD‐123319, 30 μg/kg/min, osmotic pump) or AT2‐R agonist (C21, 0.3 mg/kg, daily i.p.) for 4 days. Thereafter the animals were placed on normal chow diet (ND) or high‐fat diet (HFD) with concurrent drugs treatment for next 10 days. The PD treatment increased the ratio of total abdominal fat weight to body weight in both ND and HFD groups compared with the respective controls. Similarly, the PD treatment caused increase in epididymal fat weight in both ND and HFD. Epididymal adipocyte size was also increased in HFD group treated with PD. On the other hand, C21 treatment rescued HFD‐induced increase in epididymal fat weight and adipocyte size. The HFD‐induced increase in plasma free fatty acid level was prevented by C21 treatment. In sum, pharmacological blocking of AT2R increases and activation of AT2R decreases adipocyte size. This is the first study which demonstrates that adipocyte size increase is rescued by the pharmacological activation of AT2R, which may serve as therapeutic target for controlling obesity and associated disorders.Grant Funding Source : NIH RO1 DK‐61578
Neuroprotective Effects of Papaya Epicarp Extract against Aluminum‐Induced Oxidative Stress in Human Neuronal (SHSY5Y) Cells
Authors: Waly Mostafa , Guizani Nejib , Ali Amanat , Rahman Mohammad Shafiur , Deth Richard 
Published: June 2021

BackgroundAluminum (AL) as an environmental toxin induces oxidative stress and impairs folate‐dependent methionine synthase (MS) activity in human neuronal cells, SH‐SY5Y cells.ObjectiveThis study aimed to assess the in‐vitro antioxidant properties of the papaya epicarp extract (PEE) against AL‐induced insults in SH‐SY5Y cells.ResultsThe analyzed data revealed that PEE protects against AL‐induced cells death, and in a dose‐dependent manner it restores the inhibited folate‐dependent MS activity and antioxidant enzymes (Catalase, Glutathione Peroxidase and Superoxide Dismutase). In addition PEE augments the AL‐induced impairment of cellular glutathione, thioredoxin and total antioxidant capacity.ConclusionThis study shows that PEE supplementation has a neuroprotective role in ameliorating the changes in redox status of neural cells exposed to AL, a well known environmental toxin that has been involved in the pathogenesis of neurodegenerative diseases and neurodevelopmental disorders.
Pomegranate vinegar feeding enhances fatty acid oxidation: In vitro and in vivo
Authors: PARK YEOJIN , Ok Elly , Lee Hyo Jung , Kim Ji Yeon , Kim Mi Kyung , Kwon Oran 
Published: June 2021

Vinegar is not only commonly consumed as a seasoning and a food preservative but also used as a traditionally folk remedy from the ancient. Recent studies show an acetic acid, major component of vinegar, has beneficial effect on anti‐obesity by increasing fatty acid oxidation in liver. In this study, we screened which vinegar beverages contained acetic acid and flavonoids showed synergistic effect on stimulation of genes related fatty acid oxidation using HepG2. We selected pomegranate vinegar beverage as anti‐obesity beverage and then treated to high fat diet rats for 11weeks. After treatment, in liver, muscle, and adipose tissue, we examined several genes related on fatty acid oxidation and synthesis such as PPAR‐a, CPT‐1, ACO, UCP‐2, SREBP using pomegranate vinegar and acetic acid in animal models using RT‐PCR. And also, with western blotting in same animal models, we examined P‐AMPK/ AMPK activation in liver.*This study was supported by the 2nd stage of Brain Korea 21 Project in 2011
Prostate specific antigen: Enhancing the anti‐microbial response of the prostate during urinary tract infection
Authors: Townes Claire Louise , Ali Ased , Lanz Marcelo , Gross Naomi , Robson Craig , Pickard Robert , Hall Judith 
Published: June 2021

The inability to successfully clear an initial episode of mild cystitis may result in a greater susceptibility to recurrent urinary tract infection (rUTI). A chart review carried out at our institution showed a significantly increased risk of recurrent urinary tract infection (rUTI) in men whose prostate specific antigen (PSA) levels during an initial UTI episode were low (<4ng/ml). PSA is known to function as a serine protease and several proteins belonging to the WFDC (WAP Four Disulphide Core) family and present in semen are known to contain antimicrobial domains released by serine protease cleavage. We suggest that PSA may function to digest these proteins during UTI and therefore enhance the prostates antimicrobial response.The expression of genes encoding WFDC2 and SLPI were identified in prostate tissues by RT‐PCR. WFDC2 and SLPI expression (p<0.001) and PSA synthesis (p<0.01) were significantly increased in LnCAP and Du145 prostate cell lines challenged with Escherichia coli, as determined by realtime PCR and ELISA. The presence of PSA significantly reduced the ability of bacteria to invade prostate cells. Incubation of PSA with recombinant WFDC2 and SLPI for 24 hours resulted in total proteolysis of the full‐length protein and significantly increased antimicrobial activity. These results suggest PSA may have an important role in protecting against rUTI.
HMGB1 guides cytokines in early carbon nanoparticle lung exposure
Authors: Herndon Betty , Das Monisha , Nalvarte Elisabet , Molteni Agostino , Quinn Tim , Fibuch Eugene 
Published: June 2021

An initial effect of carbon nanoparticle (CN) lung exposure is the cellular release of damage‐associated molecular pattern recognition molecules (DAMPs). One of the earliest is the high mobility group box 1 (HMGB1) protein, which, extracellularly, exerts its actions as a ligand for pattern recognition receptor (PRR) target cell activation. This work studies HMGB1's role in damage recognition and activation of cellular processes. CN (0.025 mg, endotoxin free in 0.050 mL Survanta) was intratracheally instilled into rat airways (n=45). At necropsy 0.5hr to 4 wks later, bronchoalveolar lavage fluid (BAL), lungs and sera were measured (ELISA, cytology) for HMGB1 and 3 cytokines. BALs were also used to activate PRRs in RAW Blue cells, stably transfected lung macrophages expressing the SEAP gene inducible by NF‐kB and AP‐1. HMGB1‐containing BALs induced significant expression of SEAP in the RAW blue cells, highest at 24 hr, which was compared to purified HMGB1 dose‐dependent activation. Histopathology described Inflammation of lung parenchyma and translocation of CN from airways to the mesothelial lining. IL‐10 and IL‐6 in lung related in timing to HMGB1‐receptor complexes (p=0.04). The results show that sterile CN exposure releases lung cell HMGB1, and BAL from this exposure activates raw blue cells at times when HMGB1 is elevated, with related receptors and cytokines.Sponsor: Saint Luke's Hospital Foundation
TLR4 Overexpression After Orthotopic Liver Autotransplantation Contributes To Acute Lung Injury In Rats
Authors: Chi Xinjin , Ge Mian , Zhang Ailan , Luo Gangjian , Xia Zhengyuan , Hei Ziqing 
Published: June 2021

Acute lung injury(ALI) is a common and severe complication of orthotopic liver transplantation(OLT), while the underlying mechanism of post‐OLT ALI is not very clear. Toll‐like receptor (TLR) 4 is an important TLR family member that plays a key role in the innate immune system. TLR4 is increased after OLT, accompanied with increased inflammatory response and ALI (Chin Med J, 2009,122:895–899). We hypothesized that TLR4‐mediated inflammation response may play a ctitical role in ALI during OLT. Healthy SD rats (n=8/group) were randomly divided into sham operated control group (C) and OLT groups with different durations (4, 8 and 16 hours) of reperfusion in the presence or absence of TLR4 siRNA interference performed 48 hours before OLT. Lung tissue TLR4 gene and protein expressions were significantly increased 8 hours after OLT and onwards, which was coincident with increased tissue levels of tumor necrosis factor (TNF) α, interleukin (IL)6 and IL‐1β, and evident lung pathological damage manifested as increased lung injury scores and increased lung water content and functional impairment manifested as reduced PaO2 (all P<0.05 vs. OLT vs. C). TLR4 dominant negative siRNA prevented all the above changes after OLT. It is concluded that TLR4 overexpression, potentially by stimulting proinflammatory cytokine over production, plays a critical role in the developent of ALI after OLT.The study was supported by National Natural Science Foundation of China grant (No. 30801080 and 30972858).
Role of TRPC1 and TRPC3 channels in constriction and relaxation of mouse thoracic aorta
Authors: Kochukov Mikhail Y , Balasubramanian Adithya , Abramowitz Joel , Birnbaumer Lutz , Marrelli Sean P 
Published: June 2021

Canonical transient receptor potential (TRPC) channels expressed in smooth muscle (SMC) and endothelial cells (EC) are candidates for regulating intracellular Ca2+ and membrane potential in the vasculature. We examined the role of TRPC1 and TRPC3 channels in the mechanisms of vasocontraction and relaxation in mouse aorta.Experiments were performed with wild type (WT), TRPC1, and TRPC3 knockout (KO) mice. Contraction of aorta to phenylephrine (Phe) and relaxation to carbachol (CCh) were measured using an isometric tension bath. Intracellular Ca2+ was measured in cultured aorta EC by Fura 2. Whole cell K+ current was measured in freshly isolated SMC.Aorta from TRPC1 but not TRPC3 KO mice showed augmented contractility to Phe compared to WT. Contractions to Phe were significantly potentiated in WT (but not TRPC1) aorta in the presence of a BKCa blocker Penitrem A. In SMC, Phe‐stimulated BKCa current was reduced in TRPC1 KO compared with WT. Relaxations to CCh were significantly reduced in aorta from TRPC1 and TRPC3 KO mice. EC from TRPC1 and TRPC3 KO mice demonstrated a reduced CCh‐mediated Ca2+ response. Additionally, Ca2+ response of WT EC was attenuated by a TRPC3 blocker Pyr3.Data suggest that TRPC1 facilitates BKCa channel activation in SMC to promote attenuation of agonist‐mediated constriction. Both TRPC1 and TRPC3 contribute to endothelium‐dependent relaxation of aorta and agonist‐mediated Ca2+ influx in EC.Supported by NIH R01 HL088435 and the Intramural Research Program of the NIH, project Z01‐ES‐101684.
Key role of Pannexin‐based hemichannels in flow‐induced nitric oxide production in resistance arteries
Authors: Perez Francisco R , Gaete Pablo , Boric Mauricio , Figueroa Xavier 
Published: June 2021

Nitric oxide (NO) production and connexin‐based channels play a key role in the control and coordination of vascular function. Blood flow induces NO production by the activation of endothelial NO synthase phosphorylation at serine 1177 (P‐eNOSS1177) through the PI3K/Akt pathway. The participation of connexin‐ or pannexin‐formed hemichannels in the response to flow has not been evaluated. We used the rat arterial mesenteric bed to study the involvement of hemichannels in flow‐induced NO production. Mesenteric vessels were stimulated with flow by increasing the perfusion rate from 2 to 10 mL/min and hemichannel activity was assessed by ethidium or Lucifer Yellow uptake. Flow increased NO production, Akt‐dependent P‐eNOSS1177, ATP release and endothelial hemichannel activity. Treatment with 18‐beta‐glycyrrhetinic acid or probenecid, but not La3+, blocked the hemichannel activation and Akt dependent‐P‐eNOSS1177 induced by flow. The increase in P‐eNOSS1177 was prevented by the specific inhibition of P2Y1 receptors with MRS2179 or global inhibition of purinergic receptors with PPADS, but not by the P2X receptor blocker iso‐PPADS. These results suggest that pannexin hemichannel‐mediated ATP release is involved in the activation of NO production in response to flow, which may be involved in the development of cardiovascular diseases.FONDECYT 1100850, 1090757, 1111033, Anillos ACT‐71.
Pericytes: not only an anatomical “internet” coordinating coronary vessels, but also key functional players?
Authors: Nees Stephan , Weiss Dominik R , Juchem Gerd 
Published: June 2021

Aimsdetermination of the distribution of pericytes (P) in the human coronary system and their functional characterization. We found that interconnected P not only engird the endothelial cell tube (E) of all coronary microvessels, but also form a continuous intimal tissue net in the subendothelium of all coronary arteries and veins. Regardless of vascular origin P are typically connected to the E via abundant gap junctions. Smooth muscle cells extend down the arterial tree but stop abruptly at the junction between muscular arterioles (diam. >20 μm) and endarterioles (diam. 10–20 μm). The latter, the most important vessel segments for blood flow regulation, thus consist only of an inner E and outer tube of P. Pure cultures of P can be established in presence of human placental serum and passaged whilst retaining their typical histological and functional features. P reveal a high procoagulatory potency (activation of X, formation of the prothrombin complex). In co‐culture with endothelial cells of human coronary venular origin spontaneous formation of microvessels can be observed that resembles closely natural angiogenesis. The tip cells in capillary sprouts, though to direct this process, appear to be P and not endothelial cells. Thus, the interconnected P in the heart probably play a central role in the control of myocardial blood flow, hemostasis and angiogenesis. Supported by the Friedrich‐Baur‐Stiftung Munich.
Protective role of Ac‐SDKP and thymosin β4 on cardiac rupture after myocardial infarction
Authors: Peng Hongmei , Carretero Oscar A. , Yang Xiao-Ping , Xu Jiang , Peterson Edward , Rhaleb Nour-Eddine 
Published: June 2021

N‐acetyl‐seryl‐aspartyl‐lysyl‐proline (Ac‐SDKP), released from its precursor thymosin β4 (Tβ4), has anti‐inflammatory, pro‐angiogenic and anti‐fibrotic effects. We hypothesized that Tβ4 and Ac‐SDKP reduce cardiac rupture after myocardial infarction (MI). C57BL/6J mice were subjected to MI and divided into groups: 1) sham MI, 2) MI + vehicle (VEH), 3) MI + Ac‐SDKP or 4) MI + Tβ4. Ac‐SDKP and Tβ4 (1.6 mg/kg/day) were given i.p. via osmotic pump for 7 days before MI and 7 more days after MI. Ejection fraction (EF) was assessed by echocardiography. Infarct size was similar in all MI groups. Interstitial collagen fraction (ICF) and capillary density were measured and ICAM‐1 was detected by Western blot. Ac‐SDKP and Tβ4 decreased cardiac rupture rate, both tended to increase EF but the difference did not reach statistical significance (Table). Decline in cardiac rupture by Ac‐SDKP or Tβ4 may be due to angiogenesis, and decreased inflammation and metalloproteinase activity. The use of Ac‐SDKP and Tβ4 may reduce cardiac rupture after MI.The NIH (R01HL071806).
Incorporating Human Ventricular Fiber Architecture in Patient‐Specific Computational Models
Authors: Villongco Christopher T , Frank Lawrence R , Krummen David E , Nigam Vishal , Kerckhoffs Roy CP , Omens Jeffrey H , McCulloch Andrew D 
Published: June 2021

Patient‐specific models of the cardiac ventricles require a realistic representation of the myofiber architecture to accurately simulate mechanical and electrical properties of healthy and failing hearts. Diffusion tensor magnetic resonance imaging (DT‐MRI) techniques have made it possible to reconstruct the fiber anatomy of the ventricles. However, in vivo DT‐MRI scans are still impractical to obtain for individual patients. The aim of this study develops a method to register DT‐MRI measurements from an explanted human heart into an anatomical model and warping the result to patient‐specific anatomies using large deformation diffeomorphic mapping.An explanted human organ donor heart was subjected to a DT‐MRI scan. The raw tensor data was registered into an anatomical model of the ventricles by fitting the measured diffusion tensor components in log‐Euclidean space. A material coordinate transformation model defined a local orthogonal coordinate system representing the fiber, sheet, and sheet‐normal directions of the myocardium from the eigenvectors of a locally interpolated diffusion tensor. Diffeomorphic maps of the deformation F between the donor and patient models were computed and used to warp the donor fiber architecture into the patient models. The registration error between the eigenvectors of the measured tensor and its interpolated tensor was quantified by a scalar metric of axes overlap. It found 74% of the registered DT‐MRI data (112,419 of 152,651 voxels) had mean angular errors of 12.5°±7° (SD) in the fiber, 20°±11.5° (SD) in the sheet, and 18°±11.6° (SD) in the sheet normal axes.
Characterization of a Druggable Binding site in the Renal Outer Medullary Potassium Channel
Authors: Nguyen Thuy Tuong , Sheehan Jonathan H. , Meiler Jens , Denton Jerod S. 
Published: June 2021

The Renal Outer Medullary potassium (K+) channel, ROMK, has been postulated as a target for a novel class of loop diuretic. We recently used high‐throughput screening and medicinal chemistry to develop a highly selective small‐molecule inhibitor, termed VU591, with which to explore ROMK's physiology and therapeutic potential. Electrophysiological experiments suggested that VU591 blocks the intracellular pore of the channel. In an effort to characterize the VU591 binding site, a comparative homology model of ROMK based on the X‐ray structure of Kir2.2 was used to identify the pore‐lining residues to target for alanine‐scanning mutagenesis. Two‐electrode voltage clamp analysis of mutagenized channels expressed in Xenopus oocytes identified several pore‐lining residues that appear to be important for VU591‐dependent inhibition of ROMK. We are currently refining the mutagenesis and employing ligand‐docking simulations to help define molecular structure of the VU591 binding site.NIH R01 award to Jerod S. Denton DK082884.