bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upregulation of cellular protective mechanisms against oxidative damage via pharmacological intervention
Authors: Allani Shailaja Kesaraju , Chen Xi , Ramirez‐Alcántara Verónica , Canzoneri Joshua , Prentice Howard , Huang Xupei , Piazza Gary , Weissbach Herbert 
Published: June 2021

Oxidative damage is widely accepted as a major stress factor responsible for many age‐related diseases, as well as other degenerative conditions associated with normal aging. We initially became interested in activating or upregulating cellular protective mechanisms against oxidative damage after identifying methionine sulfoxide reductase A (MSRA), the first member of the MSR family of enzymes. The MSR system, MSRA and MSRB, reduces methionine sulfoxide residues in proteins, both the S and R epimers, back to methionine, repairing oxidative damage to proteins. MSRA can also reduce small molecules that contain a methyl sulfoxide S epimer, including the prodrug sulindac, that is converted to sulindac sulfide, the active NSAID (nonsteroidal anti‐inflammatory drug). We reported that sulindac can also protect both retinal pigmented epithelial (RPE) cells against chemical oxidative damage, and the heart against ischemia/reperfusion damage (I/R), by initiating a protective response, similar to ischemic preconditioning. This mechanism of sulindac protection was shown to be independent of its NSAID activity. In contrast, sulindac under similar conditions, sensitizes cancer cells to oxidative stress, resulting in enhanced killing of the cancer cells when they are exposed to additional stress. Because of sulindac's unique properties the National Institute of Aging recently selected sulindac to test for life span extension in mice in their Interventions Testing Program. In order to find a more active sulindac derivative that could protect cells against oxidative damage and lacked NSAID activity, we screened a series of sulindac derivatives containing a central indenyl core present in the sulindac scaffold. We have identified a compound, MCI‐100, that is not an NSAID, that is >20 fold more active than sulindac in protecting RPE cells from oxidative damage and also more active than sulindac in protecting the heart against I/R damage in a Langendorff ex‐vivo model. Additional experiments suggest that the protective mechanism of both sulndac and MCI‐100 may be related to their ability to inhibit PDE10, resulting in an increase in intracellular cGMP levels, that could initiate a pharmacological preconditioning response through PKG activation. However, unlike sulindac, MCI‐100 does not sensitize cancer cells to oxidative stress.Our eventual goal is to develop drug combinations that up‐regulate several different mechanisms that cells use to protect against oxidative damage, as a therapeutic approach to slow the progression of age related diseases, and treat other diseases that involve oxidative damage.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Development of LAT‐1 inhibitors for the treatment of pancreatic cancers
Authors: Ikhlef Houssine , Phanstiel Otto 
Published: June 2021

Pancreatic ductal adenocarcinoma (PDAC) is the most common form of pancreatic cancer and represents one of the world's most deadly cancers with a five year survival of only 8%. As such there is a desperate need to develop effective new medicines for pancreatic cancers. The large neutral aminoacid transporter 1 (LAT‐1) is highly expressed in PDAC tumors and provides a conduit for these tumors to acquire essential amino acids like leucine and methionine. Beyond their incorporation into proteins, leucine is an important regulator of mTOR signaling and methionine is essential for one carbon metabolism and polyamine biosynthesis. Targeting LAT‐1 inhibits the uptake of these essential building blocks and inhibits cell growth.There has been significant interest in developing LAT‐1 inhibitors for oncology applications and virtually all of the known LAT‐1 inhibitors are predicated upon a phenylalanine scaffold. Here, we showed that piperazine‐based materials effectively inhibited leucine and methionine import into L3.6pl human pancreatic cancer cells. We also demonstrated that our lead LAT‐1 inhibitor resulted in a dose‐dependent decrease in intracellular methionine, leucine, and depleted polyamine pools in L3.6pl cells in vitro. Moreover, these treated cells were not rescued by exogenous polyamines indicating that polyamine import could not revive the treated cells. Our different molecular design provides new opportunities for enhanced targeting and both the synthesis and bioevaluation of these new LAT‐1 inhibitor designs will be discussed.Support or Funding InformationUCF College of Medicine (#25014202)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Using simulation to probe membrane defects with a pH‐sensitive peptide
Authors: Burns Violetta , Mertz Blake 
Published: June 2021

The pH Low Insertion Peptide (pHLIP) binds, folds and inserts spontaneously into the membrane as a transmembrane helix under acidic conditions. This functionality makes pHLIP a promising tool for drug delivery and diagnostic imaging of disorders associated with acidosis, such as arthritis, cancer, and ischemia. The acidic sensitivity of pHLIP arises from the sequential protonation of its acidic residues which, after binding to the membrane, induces simultaneous folding and insertion in order to seclude its hydrophobic segment from aqueous solvent. However, the peptide‐bilayer interactions of pHLIP in the fully inserted state are poorly understood. Our aim is to characterize the effect of deprotonation of the acidic residues of pHLIP on the stability of the peptide and the bilayer in its inserted state. Our hypothesis is that increasing the degree of deprotonation of pHLIP disrupts favorable interactions between pHLIP and the bilayer. In order to test our hypothesis, we carried out molecular dynamics (MD) simulations of α‐helical pHLIP inserted into a 1‐palmitoyl‐2‐oleoyl‐sn‐3‐phosphocholine (POPC) bilayer. Our variable was the protonation state of the acidic residues in pHLIP. Our results show that in the fully protonated state, pHLIP remains stable. Interestingly, in the fully deprotonated state, the negatively‐charged residues remain embedded in the interior of the bilayer, stabilized by a defect that allows for interactions with waters from bulk solvent. In addition, deprotonation of the C‐terminal acidic residues leads to greater destabilization of pHLIP in the bilayer. Together, these results reveal several of the interactions between pHLIP and the aqueous and lipid phases that are critical in maintaining the fully inserted state of the peptide.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
A free‐exchange mathematical model of EmrE
Authors: Hussey Grant , Thomas Nathan , Henzler‐Wildman Katherine 
Published: June 2021

EmrE is a multidrug resistance transport protein from E. coli that couples the efflux of toxic, lipophilic cations to the influx of protons down their electrochemical gradient. Active transporters require alternating access between open‐in (binding pocket accessible to the cytoplasm) and open‐out (binding pocket accessible to the periplasm) conformations to move substrate across the membrane. Strict restrictions on alternating access or substrate binding lead to simplified models that achieve stoichiometric symport (coupling movement of both substrates in same direction) or “pure‐exchange” antiport (coupling movement of both substrates in opposite directions). However, recent data suggests that common strictly‐coupled models of transport may be oversimplified. For example, the EmrE point mutant, W63G, confers resistance to erythromycin, indicating H+‐coupled transport of that substrate, while also conferring susceptibility to polyamines, indicating uniport or H+‐coupled symport of those substrates. We recently developed a “free‐exchange” model of EmrE transport that can account for this behavior as well as NMR data showing that EmrE can simultaneously bind drug and proton and can alternate access when bound to both, one, or no substrates in violation of pure‐exchange models. Here, we develop a free‐exchange mathematical model to explore features that tip the balance between different H+‐coupled transport regimes. We find that under physiological conditions, transport is faster in the free‐exchange model and comparable substrate gradients can be produced. Using the available kinetic data for EmrE and our mathematical model, we show that EmrE can concentrate drug as experimentally observed in liposomal‐flux assays and also show how drug identity can switch directionality of transport, as observed for W63G‐EmrE.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Use of Cell Penetrating Peptides to Deliver Cargo in Protists
Authors: Warner Max V. , Barnhill Zoie , LeCher Julia C. , Cooper Jennifer L. 
Published: June 2021

Algae and plankton are important both ecologically as a food chain base and economically as nutraceutical “factories”. Despite their importance, technologies to transfect genes or proteins are limited or nonexistent in many protist species of interest, probably because cell walls present a barrier to macromolecular passage. We are using a novel cell penetrating peptide (CPP) system as a means to overcome this barrier. CPPs are a class of short peptides that can cross the cell membrane and sometimes the cell wall in a variety of species. Membrane translocation by CPPs involves endocytosis as well as other mechanisms. CPPs can be linked in a variety of ways to desired cargos to cause their entry into cells. Microscopic imaging of protist cells treated with CPP linked to fluorescently labeled cargo demonstrates that CPPs can cause the association of cargo with cells while fluorescently labeled cargo‐only treatment does not cause extensive cargo association with cells. Using fluorescence microscopy, we are currently optimizing the type of CPP and the CPP‐cargo uptake procedure to find the best conditions for cargo delivery to protists. We are also attempting proteolytic treatment to eliminate cargo stuck to the cell exterior and allow flow cytometric measurements of true cargo entry. Success of our method will provide a new means for rapid introduction of macromolecules into protist cells, allowing both investigation of their cellular function and potential manipulation of economically important products.Support or Funding InformationMentor Protégé Research Program, College of Science and Mathematics, Kennesaw State University; Research Opportunity Award, Office of Research, Kennesaw State UniversityThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Plasmalogen Precursors Reverse Lipid Changes in a Barth Syndrome Cell Model
Authors: Bozelli Jose Carlos , Junior  , Epand Richard M 
Published: June 2021

Barth syndrome is rare X chromosome‐linked genetic disorder that is caused by mutations in tafazzin, a phospholipid‐lysophospholipid transacylase responsible for the last step of cardiolipin (CL) biosynthesis in the mitochondria. The lipid alterations in Barth syndrome include loss in total CL content, an increase in the concentration of monolysocardiolipin (MLCL) and a greater heterogeneity of the acyl chains of CL. These changes are so characteristic of Barth syndrome that they have become the basis of diagnostic tests. Recently, one of us has demonstrated that the major change in the lipid composition of organs that have been depleted of tafazzin is the loss of plasmalogens. In several disease states where loss of plasmalogens has been reported, the condition could be reversed by the administration of plasmalogen precursors. Hence, we hypothesized that administration of plasmalogen precursors could reverse the phenotype of Barth syndrome. Here, we present the high‐resolution 31P‐NMR phospholipidomic study of the total lipid extract of a Barth syndrome cell model, i.e., lymphoblasts derived from Barth syndrome patients compared with controls in absence and presence of feeding plasmalogen precursors. Lymphoblasts derived from Barth patients in comparison to controls are ideal for studies of the mechanism as it is a single cell type that can be grown in culture and have all the characteristics of cells from patients with this Syndrome. In agreement with previous results we observed a marked decrease in plasmalogen in Barth lymphoblasts compared to controls together with other lipid alterations reported in those cells. Furthermore, as expected, feeding the cells with plasmalogen precursors restored plasmalogen levels. However, to our surprise the feeding also markedly increased the level of CL. Moreover, we also could show that the CL increase is not a consequence of a decrease in CL hydrolysis by a phospholipase (degradation) as evinced by the lack of MLCL accumulation in cells fed with plasmalogen precursors. In summary, we are able to reverse, at least in part, the lipid changes associated with Barth syndrome by feeding our cell model with plasmalogen precursors. We wish to extend these findings to determine how these changes in lipid composition affect the functioning of their mitochondria. This may present a simple and rapid process to bring these new strategies to the clinic since the precursors we are using are non‐toxic and have been administered to humans for other purposes.Support or Funding InformationAn award from the Barth Syndrome Foundation, Inc. and the Barth Syndrome Foundation of Canada.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Metabolic escape to glycolysis through SK channel activation inhibits ferroptosis and increases the life span of C. elegans in conditions of heat stress
Authors: Dolga Amalia , Krabbendam Inge , Honrath Birgit , Dilberger Benjamin , Schmidt Martina , Eckert Gunter , Culmsee Carsten 
Published: June 2021

Metabolic flexibility is a characteristic of essentially all cells in order to cope with environmental alterations. One example of adaptation is represented by a mitochondrial switch from oxidative phosphorylation (OXPHOS) to glycolysis. Attenuation of mitochondrial respiration and cell metabolic shifts have been proposed as therapeutic strategies against oxidative stress and neurodegeneration. Activation of small‐conductance Ca2+‐activated K+(SK) channels contribute to neuroprotection in conditions of oxidative stress by attenuating mitochondrial calcium ([Ca2+]m), mitochondrial reactive oxygen species (ROS) generation and mitochondrial respiration in neuronal cells. To date, potential effects of SK channels have never been studied in relation to metabolic reprogramming nor the subsequent effects on survival in whole organisms in conditions of oxidative stress. Therefore, we aim to understand the mechanism by which SK channels confer neuroprotection during ferroptosis, a form of cell death associated with oxidative stress, and whether metabolic reprogramming can be part of neuroprotection.Our data show that CyPPA, a positive modulator of SK channels, prevented cell death in conditions of ferroptosis and preserved mitochondrial function. High‐resolution respiratory revealed that opening of SK channels alone resulted in a mild decrease of mitochondrial complex I activity. These effects were accompanied by a slight increase in mitochondrial ROS production and depolarization of the mitochondrial membrane, suggesting preconditioning mechanisms to be also involved in the neuroprotection. Experiments where mitochondrial ROS were scavenged showed reduced capacity of CyPPA to mediate neuroprotection. Interestingly, extracellular flux analysis by Seahorse flux analysis technology revealed a CyPPA‐mediated initial increase in glycolysis followed by a slight reduction of OXPHOS activity. Induction of glycolysis was crucial for the neuroprotective effects of the SK channel opener, since substances that inhibit glycolysis were able to restore the cell sensitivity to ferroptosis even in the presence of CyPPA. Importantly, we found CyPPA to increase survival of C. elegans challenged with mitochondrial toxins in conditions of heat stress. These findings shed light on new molecular mechanisms mediated by SK channels that could explain the increased neuroprotective capacity in conditions of ferroptosis and neurodegeneration.Support or Funding InformationA.M.D. is the recipient of a Rosalind Franklin Fellowship co‐funded by the European Union and the University of Groningen.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Aloe‐emodin inhibits hypertension‐induced inter‐endothelial junction dysfunction through endothelial ROS‐TXNIP‐Nlrp3 inflammasome axle
Authors: Zhang Yi , Ye Lifeng , Wang Yunting , Zhang Yang , Li Pinlan , Chen Yang 
Published: June 2021

Recent studies have revealed that Aloe‐emodin, a natural compound from the root and rhizome of Rheum palmatum L., exhibits significant pharmacological activities. However, the pharmacological relevance of the compound, particularly for cardiovascular disease, remains largely unknown. Here, we hypothesized that Aloe‐emodin could improve endothelial injury by inhibiting the activation of Nlrp3 inflammasome, and ultimately prevent cardiovascular disease. In vitro, our findings demonstrated that Aloe‐emodin inhibits AngII‐induced Nlrp3 inflammasome formation and activation in Microvascular Endothelial Cells (MECs), as shown by fluorescence confocal microscopy and Western blot. At the same time, the data shown that Aloe‐emodin exerts anti‐oxidation and ROS scavenged effects. Interestingly, thioredoxin‐interacting protein (TXNIP) protein and high mobility group box 1 (HMGB1) markedly decreased with Aloe‐emodin treatment. We also demonstrated that the decreased expression of the tight junction proteins ZO‐1/ZO‐2, which are related to endothelial permeability after stimulation by AngII in endothelial cells. Aloe‐emodin could recover the gap junction protein and decrease monolayer cell permeability in endothelial cells. Similarly, we used confocal microscopy to study the formation and activation of NOD‐like receptor family pyrin domain containing‐3 (Nlrp3) inflammasomes and expression of tight junction proteins in coronary arteries of AngII/DOCA‐treated mice. We found that Aloe‐emodin inhibited the formation and activation of Nlrp3 inflammasome, and also could restore the expression of the endothelial connective protein ZO1/2 and the release of HMGB1. Together with these changes, we revealed a new protection mechanism of Aloe‐emodin that inhibits Nlrp3 inflammasome activation and decreases subsequent caspase‐1 activation, triggering the release of HMGB1 by reducing ROS generation. Our findings indicate that Aloe‐emodin exhibits immense potential and specific therapeutic value in hypertension‐related cardiovascular disease and the development of innovative drugs.Support or Funding InformationThe National Key Research and Development Program of China (No. 2017YFC1700400); the project supported by National Natural Science Foundation of China (No. 81603587); Guangdong Natural Science Funds for Distinguished Young Scholar (No. 2018B030306027); Science and Technology Development Plan of Guangdong Province (No. 2017A020211016)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.
Impact of apolipoprotein A1‐ or Lecithin:cholesterol acyltransferase‐deficiency on white adipose tissue metabolic activity and glucose homeostasis in mice
Authors: KYPREOS KYRIAKOS E , XEPAPADAKI EVA , SASSON SHLOMO , MAULUCCI GIUSEPPE , CONSTANTINOU CATERINA , KARAVIA ELENI A , ZVINTZOU EVANGELIA 
Published: June 2021

High density lipoprotein (HDL) has attracted the attention of the biomedical community due to its well‐documented role in atheroprotection. HDL has been recently implicated in the regulation of islets of Langerhans secretory function and in the etiology of peripheral tissue insulin sensitivity. Indeed, data from numerous studies strongly indicate that β‐cells, as well as skeletal muscles and adipose tissue could benefit from improved HDL functionality. To better understand how changes in HDL structure may affect diet‐induced obesity and type 2 diabetes we aimed at investigating how deficiency in Apoa1 or Lcat, two key proteins of peripheral HDL metabolic pathway, could affect these pathological conditions in mouse models. We report that universal deletion of apoa1 or lcat expression in mice fed western‐type diet results in increased sensitivity to body‐weight gain compared to control C57BL/6 group. These changes in mouse genome correlate with discreet effects on WAT metabolic activation and plasma glucose homeostasis. Apoa1‐deficiency results in reduced WAT mitochondrial non‐shivering thermogenesis. Lcat‐deficiency causes a concerted reduction in both WAT oxidative phosphorylation and non‐shivering thermogenesis, rendering lcat−/− mice the most sensitive to weight gain out of the three strains tested, followed by apoa1−/− mice. Nevertheless, only apoa1−/− animals show disturbed plasma glucose homeostasis due to non‐responsive pancreatic β‐islets to glucose and insulin resistant skeletal muscles. Our analyses show that both apoa1−/− and lcat−/− mice fed high‐fat diet have no measurable Apoa1 levels in their plasma, suggesting that other HDL components may be responsible for the observed phenotypic differences among groups.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.