bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chlorinated Lipids Activate Human Neutrophils
Authors: Palladino Elisa N. D. , Ford David A 
Published: November 2023

Neutrophil activation is orchestrated by a complex array of mechanisms including phosphorylation and activation of NADPH oxidase and subsequent hydrogen peroxide consumption by myeloperoxidase leading to hypochlorous acid (HOCl) production. Our research group has previously shown that the vinyl ether bond of plasmalogen phospholipids is targeted by HOCl in activated leukocytes, which results in the production of 2‐chlorofatty aldehyde (2‐ClFALD). 2‐ClFALD is also oxidized to 2‐chlorofatty acid (2‐ClFA) in neutrophils. The role of these two chlorinated lipids on neutrophil activation was investigated in the present study. 2‐ClFALD production was used as an indicator of the transition from quiescent to activated neutrophils when treated with chlorinated lipids. Treatment with the 2‐ClFA, 2‐chlorohexadecanoic acid (2‐ClHA), resulted in neutrophil 2‐ClFALD production, which included both 2‐chlorohexadecanal (2‐ClHDA) and 2‐chlorooctadecanal (2‐ClODA) molecular species. In contrast, 2‐ClHDA did not result in 2‐ClFALD production (monitored by 2‐ClODA production). 2‐ClFALD production elicited by 2‐ClHA was less than that elicited by phorbol myristate acetate (PMA), but concomitant PMA and 2‐ClHA treatments led to a greater amount of 2‐ClFALD production compared to the individual treatments. Employing selective pathway inhibitors, it was shown that unlike the neutrophil activation pathway stimulated by PMA, the pathway activated by 2‐ClHA is PKC‐, ERK1/2‐ and calcium‐independent. Further studies comparing human neutrophils and neutrophil‐like HL‐60 cells, demonstrated that these cells disparately respond to PMA and 2‐ClHA suggesting that further detailed comparisons between these cell types may provide additional insights into the mechanisms mediated by 2‐ClFA‐mediated neutrophil activation. In summary, 2‐ClFA may be an important mediator produced during inflammation, which is responsible for the regulation of one of the major defense mechanisms used by innate immunity.Support or Funding InformationNational Institutes of Health Grant GM115553
N‐Docosahexaenoylethanolamine ameliorates LPS‐induced brain inflammation through suppression of neutrophil/macrophage as well as microglia activation
Authors: Park Taeyeop , Lee Jiwon , Chen Huazhen , Kim Hee‐Yong 
Published: November 2023

Inflammation is a widely accepted common factor among various neuropathological processes and has been implicated as a critical mechanism responsible for the progression of neurodegeneration. Brain inflammation is characterized by glial cell activation accompanied by production of inflammation‐related cytokines, chemokines and nitric oxide (NO).Synaptamide (N‐docosahexaenoylethanolamine) is synthesized from docosahexaenoic acid (DHA) in the brain and potently induces neurite growth and synaptogenesis in developing neurons and neurogenic differentiation of neural stem cells (NSCs). Growing evidence also suggests that DHA‐derived metabolites have anti‐inflammatory and pro‐resolving effects, however, the role of synaptamide in the brain inflammation is unknown. Thus, we investigated synaptamide effects on lipopolysaccharide (LPS)‐induced cytokine, chemokines, and iNOS expression in the brain, along with possible mechanisms.We found that synaptamide significantly reduces LPS‐induced production of TNF‐α and Nitric oxide in microglia cells with concomitant induction of cAMP/PKA phosphorylation. Conversely, adenylyl cyclase or PKA inhibitors abolished the synaptamide effect on TNF‐α expression. More importantly, we found that in vivo administration of synaptmide almost completely suppresses brain inflammatory response, including morphological activation of microglia and astrocytes, mRNA expression of inflammatory cytokines, chemokine and iNOS in the brain. Interestingly, we also found that synaptamide exerts anti‐inflammatory effect on neutrophil and macrophage cells. Taken together, our findings suggest that synaptamide can reduce LPS‐induced brain inflammation through suppression of microglia, neutrophil and macrophage activation. The synaptamide‐mediated mechanism contributes to the protective effects of DHA against neuroinflammation, and may provide a new therapeutic target to ameliorate the inflammation‐induced brain dysfunction.
Hepatic Stearoyl‐CoA Desaturase deficiency suppresses gluconeogenesis by regulating lipid profile of mitochondria
Authors: Guo Changan , Ntambi James M 
Published: November 2023

Obesity plays a central role in the metabolic syndrome, which includes hyperinsulinemia, hypertension, hyperlipidemia and an increased risk of atherosclerotic cardiovascular disease. A common health complication observed in obese patients is insulin resistance, a condition in which increased insulin levels are required to maintain normal blood glucose levels. Without proper intervention, the condition often deteriorates into type 2 diabetes mellitus, characterized by increased hepatic glucose production, and decreased glucose clearance by insulin‐responsive tissues. It has been suggested that high glucose is associated with increased oxidative stress, enhanced leukocyte‐endothelial interaction, and glycosylation of lipoproteins, apolipoproteins, and clotting factors. Identification of new therapeutic approaches to improve glycemic management via the inhibition of hepatic glucose production will be beneficial for diabetes, cardiovascular diseases and related metabolic disorders.Stearoyl‐CoA desaturase (SCD) expressed at high levels in several human tissues is required for the biosynthesis of oleate (18:1) and palmitoleate (16:1), which are the major monounsaturated fatty acids of membrane phospholipids, triglycerides and cholesterol esters. Given the multiple roles of monounsaturated fatty acids, variation in stearoyl‐CoA desaturase activity in mammals would be expected to have a major effect on lipid metabolism. We and others have reported that global deletion of SCD1 in mice dramatically increases whole body energy expenditure and the loss of SCD1 activity in the liver suppresses hepatic glucose production when mice were fed a lipogenic diet. We hypothesize that the deficiency of SCD alters energy metabolism at the cellular level via the regulation of mitochondria function. Our preliminary data suggest that hepatic SCD1 deficiency alters the lipid profile of mitochondria membrane, therefore alters the membrane potential and metabolic rate of the cell. In addition, we show that the pharmaceutical inhibition of SCD activity reduces hepatic glucose production in the cell culture conditions. These studies provide essential information on the role of SCD on energy metabolism and, at the same time validate hepatic SCD enzymes as therapeutic targets against hyperglycemia in disease conditions, such as diabetes and metabolic syndrome.Support or Funding InformationAmerican Diabetes Association 7‐13‐BS‐118
Diacylglycerol Kinase ζ Produces 16:0‐containing Phosphatidic Acid Molecular Species during Neuroblastoma Cell Differentiation
Authors: MIZUNO Satoru , Sakane Fumio 
Published: November 2023

Phosphatidic acid (PA) is one of the phospholipids composing the plasma membrane and acts as a second messenger to regulate a wide variety of cellular functions, including cell growth, migration and differentiation. PA consists of various molecular species with different acyl chains at the sn‐1 and sn‐2 positions. However, it was unclear which PA molecular species were produced during cell stimulation. In this study, we identified the PA molecular species produced during neuroblastoma cell differentiation and the PA species production pathway using our previously developed liquid chromatography (LC)/mass spectrometry (MS) method (1).First, mouse neuroblastoma Neuro‐2a cells were differentiated by treatment with 20 μM retinoic acid (RA) for 24 hours. LC/MS analysis showed that the amount of total PA was significantly increased in RA treated Neuro‐2a cells (1.69‐fold). Notably, the amount of 30:0‐ and 32:0‐PA species were dramatically increased in RA treated Neuro‐2a cells (2.13‐, 4.67‐ and 1.85‐fold, respectively). Similar results were obtained when Neuro‐2a cells were treated with serum starvation for 24 hours. MS/MS analysis revealed that these PA species commonly contain palmitic acid (16:0). Next, we examined the production pathway of 30:0‐ and 32:0‐PA. FIPI, phospholipase D‐specific inhibitor, did not inhibit the production of these PA species. RT‐PCR analysis showed that diacylglycerol kinase (DGK) δ and DGKζ were highly expressed in Neuro‐2a cells. The silencing of DGKδ expression did not decrease the production of the PA species. However, DGKζ‐specific siRNA significantly decreased the production of 30:0‐ and 32:0‐PA. In addition, DGKζ‐specific siRNA substantially attenuated neurite outgrowth/differentiation. These results suggest that DGKζ produces 16:0‐containing 30:0‐ and 32:0‐PA species and regulates neurite outgrowth during neuroblastoma cell differentiation.Support or Funding Information
Choline Deficiency Alters Lipid Droplet Composition and Size
Authors: Brown Elizabeth , Townsend Elizabeth , Hains Anastasia , Listenberger Laura 
Published: November 2023

Excess lipid is stored in organelles known as lipid droplets. The surface of a lipid droplet is a phospholipid monolayer composed primarily of two phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Specific proteins decorate the surface of each lipid droplet and regulate its activity. We aimed to determine whether the phospholipid composition of the lipid droplet surface influences the number and type of lipid droplet proteins. We cultured NIH 3T3 cells in choline deficient media and measured a decrease in the PC:PE ratio in lipid droplet fractions. While total levels of lipid droplet proteins were not changed, choline deficient media altered the lipid droplet binding of a subset of proteins. For example, cells grown in choline deficient media had 1.4 and 1.6‐fold more perilipin 2 and 3 fractionating with lipid droplets. Moreover, cells grown in choline deficient media accumulated larger and more numerous lipid droplets following oleate supplementation than cells grown with choline. Our studies link lipid droplet phospholipid composition and protein binding to cellular lipid homeostasis.Support or Funding InformationThis research was funded by St. Olaf College CURI, the Mindlin Foundation, and an ASBMB undergraduate research award (to EB).
PGC‐1α‐mediated Changes in Phospholipid Profiles of Exercise‐trained Skeletal Muscle
Authors: Miura Shinji , Senoo Nanami , Miyoshi Noriyuki , Goto‐Inoue Naoko , Minami Kimiko , Yoshimura Ryoji , Morita Akihito , Sawada Naoki , Matsuda Junichiro , Ogawa Yoshihiro , Setou Mitsutoshi , Kamei Yasutomi 
Published: November 2023

Exercise training influences phospholipid fatty acid composition in skeletal muscle and these changes are associated with physiological phenotypes; however, the molecular mechanism of this influence on compositional changes is poorly understood. Peroxisome proliferator‐activated receptor γ coactivator 1α (PGC‐1α), a nuclear receptor coactivator, promotes mitochondrial biogenesis, the fiber‐type switch to oxidative fibers, and angiogenesis in skeletal muscle. Because exercise training induces these adaptations, together with increased PGC‐1α, PGC‐1α may contribute to the exercise‐mediated change in phospholipid fatty acid composition. To determine the role of PGC‐1α, we performed lipidomics analyses of skeletal muscle from genetically modified mice that overexpress PGC‐1α in skeletal muscle or that carry knockout alleles of PGC‐1α. The overexpression of PGC‐1α in the skeletal muscle caused a significant change in the phosphatidylcholine (PC) and phosphatidylethanolamine (PE) profiles of the muscle. The PC and PE profile of EDL from PGC‐1α‐Tg mice, which showed oxidative characteristics, was similar to the profile of the originally oxidative muscle, such as the soleus. We also found that PGC‐1α increased several phospholipid species in glycolytic muscle, namely PC (18:0/22:6) and PE (18:0/22:6). Exercise training increased PC (18:0/22:6) and PE (18:0/22:6) in glycolytic muscle and that PGC‐1α was required for these alterations. Since phospholipid fatty acid composition influences cell permeability and receptor stability at the cell membrane, these phospholipids may contribute to exercise training‐mediated functional changes in the skeletal muscle.Support or Funding InformationThis study was supported by the Council for Science, Technology and Innovation (CSTI), Cross‐ministerial Strategic Innovation Promotion Program (SIP, No.14533567), and “Technologies for creating next‐generation agriculture, forestry and fisheries” (funding agency: Bio‐oriented Technology Research Advancement Institution, NARO), The Tojuro Iijima Foundation for Food Science and Technology (Chiba, Japan), Grants‐in‐Aid for Scientific Research (KAKENHI, No. 26282184, 26560400, 21300240) from the Japanese Ministry of Education, Culture, Sports, Science and Technology (MEXT, Tokyo), The Uehara Memorial Foundation (Tokyo, Japan), The Kao Research Council for the Study of Healthcare Science (Tokyo, Japan, No. A‐31006), and University of Shizuoka Grant for Scientific and Educational Research.
Substrate selectivity of Lysophospholipid Transporter LplT Involved in Membrane Phospholipid Remodeling in Escherichia coli
Authors: Lin Yibin , Bogdanov Mikhail , Tong Shuilong , Guan Ziqiang , Zheng Lei 
Published: November 2023

Lysophospholipid transporter (LplT) was previously found to be primarily involved in 2‐ acyl lyso‐PE recycling in gram‐negative bacterium. This work identified the potent role of LplT in maintaining membrane stability and integrity in E.coli envelope. We demonstrated the involvement of LplT in the recycling of three major bacterial phospholipids by using combination of in vitro lysophospholipid binding assay with purified protein and transport assays with E.coli spheroplasts. Our results showed that lyso‐PE and lyso‐PG, but not lyso‐PC, were taken up by LplT for reacylation by acyltransferase/acylACP synthetase (Aas) on the inner leaflet of the membrane. We also found a novel cardiolipin hydrolysis reaction by phospholipase A2 to form diacylated cardiolipin and eventually the completely deacylated head group. These two distinct cardiolipin derivatives were both translocated with comparable efficiency to generate tri‐acylated cardiolipin by Aas, demonstrating the first evidence of cardiolipin remodeling in bacterium and supporting a notion that fatty acid chain is not required for LplT transport. We also found that LplT cannot transport lyso‐PA and its substrate binding was not inhibited by either orthophosphate or glycerol‐3‐ phosphate, revealing that glycerol or ethanolamine head group is the chemical determinant for substrate recognition. Any diacyl form of PE, PG or tetra‐acylated form of cardiolipin could not serve as competitive inhibitors in vitro. Based on an evolutionary structural model, a proposed “sideways sliding” mechanism explains how a conserved membrane‐embedded α‐helical interface excludes diacylphospholipids from the LplT binding site to facilitate efficient flipping of lysophosholipid across the cell membrane.Support or Funding InformationThis work was supported by NIH grant R01 to Lei Zheng.
Investigation of Molecular Interactions Between Lysophospholipase A2 and its Diverse Bioactive Lipid Substrates
Authors: Wepy James Anthony , Xu Shu , Kudalkar Shalley Nadish , Marnett Lawrence J 
Published: November 2023

Lysophospholipase A2 (LYPLA2) is a serine hydrolase responsible for the hydrolysis of lysophospholipids, including lysophosphatidic acids, lysophosphatidylcholines and lysophosphatidylserines. These lysophospholipids are known to elicit a variety of physiological effects, such as the activation and recruitment of phagocytes, induction of cytokine expression, aggregation of platelets, calcium mobilization, and proliferation of vascular smooth muscle cells. We have also recently identified LYPLA2 as the major prostaglandin glyceryl ester (PGG) hydrolase in human cancer cells. These metabolites of the endocannabinoid species, 2‐arachidonoylglycerol (2‐AG), are precursors to the bioactive prostaglandin species, which also elicit a variety of effects, including vasoregulation, hyperalgesia, and inflammatory responses.With purified recombinant LYPLA2, we have used mass spectrometric approaches to evaluate and compare the kinetic rates of hydrolysis of its various substrates, including PGGs, lysophospholipids, and the prostanoid precursors, 2‐AG and arachidonoylethanolamide. With these data, we have shown that LYPLA2 preferentially hydrolyzes 1‐glyceryl esters of esterified lipids, and selectively metabolizes PGGs over their endocannabinoid precursor, 2‐AG. We have recently solved the first crystal structure of LYPLA2 and used this data to develop site‐directed mutants, providing new insights into the binding site of this enzyme. Structural investigations of LYPLA2 reveal a large channel at the surface of the protein, as well as a mobile loop near its catalytic triad. To further investigate the binding site interactions of LYPLA2 with its structurally diverse substrates, site‐directed mutagenesis was employed to express, purify and assess the hydrolytic activity of mutants at these hypothesized binding sites. Mutations of amino acids located in the surface channel were mutated to large tryptophan residues to sterically hinder binding of lipid substrates in the channel, and have shown to significantly inhibit the enzyme's hydrolytic activity. Here we describe the first kinetic analyses of this enzyme's ability to hydrolyze a wide range of PGG, endocannabinoid, and lysophospholipid substrates. Collectively, these data provide the first structural interpretation of the interactions of LYPLA2 with its bioactive lipid substrates.Support or Funding InformationAuthors would like to acknowledge sources of funding for this research including:Center in Molecular Toxicology Predoctoral Training Grant (NIEHS T32 ES007028)National Institute of Health Research Grant (GM15431)
The Biotech Explorers Pathway: Teams Taking First Steps Toward Scientific Challenges
Authors: Cascella Barbara G. , Jez Joseph M. 
Published: November 2023

The Biotech Explorers Pathway (BEP) is a new HHMI‐funded two‐year academic program at Washington University in St. Louis for underclassmen of varying academic interests. The primary goal of the BEP is to provide real‐world context for scientific concepts to help students assimilate the material of introductory STEM courses. A breadth of biotech topics are covered in the semester‐long introductory BEP course (Bio2010: Science of Biotech), with students synthesizing connections between science, technology, engineering, and business by working in small teams to research, write, and present case studies of St. Louis‐area biotech companies. In the second‐semester seminar course (Bio2020: Biotech Entrepreneurs Seminar), continuing students will learn directly from local biotech executives and entrepreneurs about the process and challenges of bringing an idea to fruition as a real product. Students will use what they learned from the first‐year BEP courses as they write proposals, pitch their ideas, and receive feedback from their peers and a small advisory board during the second‐year BEP course (Bio3010: Biotech Project). Active learning through team‐based inquiry and application of knowledge are the hallmarks of the BEP, with student learning monitored through pre‐ and post‐course assessments. Gains in student learning of basic and advanced scientific concepts, as well as changes in student career goals and general attitudes toward science, will be evaluated. We anticipate that the first cohort of 18 BEP students will demonstrate enhanced understanding of scientific concepts in the introductory Biology and Chemistry courses when compared with traditional STEM students, as shown by overall STEM grade point average. Additionally, we hypothesize that the STEM attrition rate will be lower for BEP students when compared to their peers.Support or Funding InformationHHMI Professor grant awarded to Joseph M. Jez
Teaching Matters: Undergraduate Grant Writing Curriculum
Authors: Miller Keith Russell 
Published: November 2023

Little literature on grant writing courses/assignments in undergraduate education exists. To gather data and best practices, a semester long undergraduate grant writing assignment was developed as an introduction to the grant writing process. This assignment was tested in both a seven‐week advanced biochemistry laboratory setting and semester long advanced biochemistry lecture course. The goal of the assignment was to progress student learning from passive to active engagement as the students developed their own solutions to self‐identified problems in biochemistry using primary literature. To achieve this goal, scaffolding of assignments, graded rubrics for all drafts, peer reviews and one‐on‐one meetings were utilized. Assessment of the assignment was completed using student evaluations, unsolicited emails, student writing samples, student peer reviews/reflections, and research faculty assessment of their students. Conclusions drawn from these various areas demonstrated that students were better prepared for research, had improved scientific communication skills, and had developed real world skills.Support or Funding InformationDepartment of Chemistry and Biochemistry at the University of Mount Union
Research as a Tool for Undergraduate Education using Drosophila melanogaster
Authors: Rogers Ryan Patricia 
Published: November 2023

Drosophila melanogaster have a myriad of applications in biological research. However, it is the ease of maintenance and availability of their fully sequenced genomes that make them a practical and constructive tool for undergraduate experiential learning. Using these organisms allows students to apply routine laboratory techniques to develop independent protocols, rather than following a pre‐derived approach. Students receive preliminary training in Drosophila husbandry as well as molecular and genetic lab techniques early in the semester in the form of short inquiry based labs and then apply learned techniques to independently developed questions. This setting recapitulates the environment of a research‐intensive lab and provides valuable experience for scientific careers. The abstraction of such an assignment forces independent thinking and practice with multiple techniques; thus, it directly engages students in the learning process by allowing them to take ownership of the project and incorporate individuality into their approaches. Further, students are immersed in a situation where they must apply themselves, think critically, and extrapolate from limited information in order to devise an appropriate course of action. Since there is no correct answer for this type of exercise, students are more willing to vary their approaches, take risks with techniques, and leave the lab with a better understanding for problem solving methods. Such skills are not specific to science, as all careers require critical thinking and troubleshooting. Early exposure to such conditions provides a basis for approaching challenging situations. Students that have successfully completed the course have been able to secure positions in competitive internships, co‐ops, and go on to research‐based careers.Support or Funding InformationThis work was supported by funds from the Department of Sciences at Wentworth Institute of Technology