bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mitochondrial Dysfunction Promotes Diabetes via A Previously Unrecognized Mechanism: Protein Succinylation
Authors: Lee Sooyeon , Annes Justin P. 
Published: April 2020

Mitochondrial dysfunction is a central contributor to the development of β‐cell failure and Type 2 Diabetes (T2D). Succinate dehydrogenase subunit B (SDHB) is a key component of the Succinate Dehydrogenase (SDH) protein complex that strongly impacts mitochondrial function via 1) oxidation of succinate to fumarate in the TCA cycle and 2) electron transfer in the electron transport chain as Complex II. Loss of SDH activity has been observed in diabetic β‐cells (humans and rodents); however, the relevance of this observation to diabetes pathogenesis remains poorly understood. Consistent with prior work, we found reduced SDHB expression in the pancreatic islets of human diabetics. To investigate the links between mitochondrial dysfunction, β‐cell failure and diabetes, we generated mice with a β‐cell‐specific knockout of SDHB (SDHBβKO). We found that SDHBβKO mice develop early onset diabetes. At 5 weeks, prediabetic SDHBβKO mice demonstrate mildly elevated glucose levels with low insulin levels and normal insulin sensitivity. These in vivo findings were confirmed by a reduction in glucose‐stimulated insulin secretion in SDHBβKO islets. Furthermore, glucose‐induced β‐cell replication was impaired in SDHBβKO mice; consistent with impaired adaptive β‐cell expansion. Given the prominent role of glucose metabolism in controlling β‐cell insulin secretion and replication, we assessed the mitochondrial bioenergetics by Seahorse Assay and found that basal and glucose‐stimulated respiration were significantly reduced in SDHBβKO islets. Notably, loss of SDH is expected to increase succinate accumulation and promote protein succinylation, a recently described bulky post‐translational modification. Indeed, SDHBβKO islets demonstrated a dramatic increase in succinate levels (16‐fold) and protein succinylation (6‐fold), providing a potential mechanism for global mitochondrial dysfunction. Accordingly, expression of the desuccinylation enzyme, Sirt5, was increased in SDHBβKO islets. Metabolomics by mass spectrometry and transcriptomics by high‐throughput RNA sequencing revealed significantly altered mitochondrial metabolism. Finally, protein succinylation levels were increased in islets of diabetic db/db mice indicating lysine‐succinylation may be characteristic of diabetes. Taken together, these results demonstrate a surprisingly necessary role for the SDH complex in β‐cell function and introduce a pathogenic mechanism of diabetes based upon β‐cell metabolic dysfunction.Support or Funding InformationStanford Diabetes Research Center (SRDC) Pilot & Feasibility Grants Program (P30DK116074), Endocrinology Training grant (T32DK007217) and Child Health Research Institute at Stanford (UL1TR001085)
The Effects of Alcohol on MAP‐Kinase Tight Junction Regulation in Lymphatic Endothelial Cells
Authors: Herrera Matthew J. , Souza-Smith Flavia 
Published: April 2020

Alcohol is known to cause lymphatic vessel hyperpermeability, leading to disrupted immune crosstalk between the gut and mesenteric lymph nodes. However, the mechanism of this alcohol‐induced hyperpermeability is unknown. The permeability of endothelial cell layers is correlated to decreased expression of certain proteins located at cell‐to‐cell contacts, known as tight junction (TJ) and adherens junctions (AJ). Proteins in these junctions, which predominantly include Claudin, Occludin, ZO‐1, and VE‐Cadherin, are shown to be regulated by MAP‐kinase proteins Erk1/2 and p38. In various endothelial cell types, alcohol increases phosphorylation of MAP‐Kinase proteins, leading to alterations in expression of TJ proteins. We hypothesize that alcohol induces lymphatic endothelial cell permeability via disruption of lymphatic endothelial cell TJs through activation of the MAP‐kinase pathway. To characterize the effects of alcohol on cellular permeability, we used and in vitro model of rat lymphatic endothelial cells. Alcohol‐supplemented medium was added at concentrations of 25 mM and 50 mM to confluent cells, and the transendothelial resistance across the cell monolayer, which is inversely related to permeability, was measured. After characterization of permeability, we measured phosphorylated states of MAP‐kinase proteins, specifically Erk1/2 and p38, at the time point that was associated with the maximum change in resistance. Our results show that alcohol increases the permeability of the endothelial cell monolayer compared to controls lacking alcohol. We also found that, at 50 mM alcohol, there was an increase in phosphorylated levels of p38 compared to controls. We predict that p38 might be affecting the expression or translocation of TJ and AJ proteins involved in forming and maintaining cell‐to‐cell adhesion, leading to increased permeability and lymphatic vessel leakage.Support or Funding InformationLSUHSC Department of Physiology NIAAA ‐ K01 AA026640‐01 (FSS)
Impact of artificial sweeteners on cellular growth and signaling pathways
Authors: Parmar Nitika , Cuxil Lily Apen , Ruano Patricio 
Published: April 2020

Artificial sweeteners such as saccharin, acesulfame, aspartame, neotame, and sucralose are found in a wide variety of foods today, particularly in zero‐calorie sugar substitutes (Equal, Sweet’ N Low, Splenda). Research conducted on animals and human epidemiological studies involving use of these compounds have provided contradictory results, in some cases indicating the compounds as safe and in others, as causing cancer. In our project, we sought to analyze the impact of six different synthetic sugar substitutes (found in Whole Earth, Equal, Splenda, Sweet’ N Low, Nutrasweet and Nutame) on bacterial and mammalian cell growth. The commercial substitutes as well as the purified ingredients found in these substitutes (erythritol, xylitol, stevia, monkfruit extract) were both tested. In this two‐phase project, E. coli cells were grown on minimal media lacking glucose but supplemented with the substitutes to determine the impact on growth. Bacterial cells were exposed to 0.4% of the compounds (0.4% is the standard glucose concentration found in rich LB media) and grown on media plates as well as in liquid cultures. Positive controls included minimal media plates containing glucose as well as rich media LB plates; negative controls included minimal media plates lacking any sugars. Our results indicate that bacteria are able to metabolize the sweeteners at different capacities but are unable to grow in acelsulfame‐K as well as the Whole Earth sweetener. A dose‐dependent profile to monitor whether bacteria will be able to utilize these compounds at higher doses (>0.4%) or will be able to survive if exposed to much lower doses (<0.1%) indicated that the growth increased with increasing concentration of the sweetener until 1%. In the second phase of our study we are growing mammalian normal (HEK293) and cancer cell lines in the presence of these substitutes at different concentrations and analyzing the impact specifically on the the mTOR signaling pathway that has been linked to a wide variety of cancers. Since some sugar substitutes have been linked to cancers in animals (e.g. sucralose to bladder cancer in rats) and considering the enormous use of these sweeteners today, this study will provide useful findings that could have important implications for their continued usage.Support or Funding InformationThis work is being supported by a UNIV498 Faculty‐Student Collaborative Research Award from CSU, Channel Islands to Nitika Parmar
Developing and Evaluating Recombinant Immunotoxins against Latent Epstein Barr Virus Infected Cells
Authors: Zhu Yuyi , Weldon John 
Published: April 2020

Epstein Barr virus (EBV), commonly associated with acute infectious mononucleosis, is an oncogenic virus implicated in thousands of cancer‐related deaths every year worldwide. Estimates suggest that 90–95% of the population worldwide are infected with EBV. Individuals with healthy immune system can manage acute infections with minimal symptoms, but EBV often persists in a latent state even after the acute infection has cleared. Studies have shown a definitive link between latent EBV infections and the development of certain cancers such as nasopharyngeal cancer and Burkitt’s lymphoma, yet there are currently no targeted treatments against latent EBV induced cancers. A potential treatment for both latent EBV infections and EBV‐induced malignancies is recombinant immunotoxins (RITs) targeted to the virus‐specific membrane protein, LMP1. RITs are fusion proteins comprised of an antibody and protein toxin designed to identify and kill specific populations of cells. RITs using the bacterial toxin Pseudomonas exotoxin A (PE) have been extensively studied. Several RITs are in clinical trials, and one (moxetumomab pasudotox) has received FDA approval for the treatment of Hairy Cell Leukemia. Using a previously developed anti‐LMP1 antibody, we have cloned, expressed, and purified two anti‐LMP1 single‐chain variable fragment antibody joined recombinantly to either PE24 or PE38. We have begun to develop a HEK293 cell line that expresses LMP1 in order to evaluate the cytotoxicity of our anti‐LMP1 RITs. Subsequent experiments will evaluate these RITs as a therapeutic against EBV‐infected cell lines.Support or Funding InformationThis project was support by the Towson University’s Graduate Student Association and the Fisher College of Science and Mathematics
Mesenchymal Stem Cells Elicit Macrophages into M2 Phenotype via Improving TFEB‐mediated Autophagy to Alleviate Diabetic Nephropathy
Authors: Yuan Yujia , Zhu Lingling , Lu Yanrong 
Published: April 2020

Diabetic nephropathy (DN) is a leading cause of end‐stage renal disease. Chronic inflammation is recognized as a key causal factor in the development and progression of DN, and the imbalance of M1/M2 macrophages (Mϕ) contributes to this process. Mesenchymal stem cells (MSCs) have been reported to prevent renal injuries via immune regulation in diabetic models, but whether these benefits are owing to the regulation of Mϕ, and the underlying signaling pathways are unknown. Here, we showed that MSCs elicited Mϕ into M2 phenotype and prevented renal injuries in DN mice, but these effects were abolished when the Mϕ were depleted by clodronate liposomes (Lipo‐Clod), suggesting that Mϕ were necessary for renal protection of MSCs in DN mice. Moreover, the MSCs promoted M2 polarization was attributable to the activation of TFEB and subsequent restore of lysosomal function and autophagy activity in Mϕ. Furthermore, in vivo adoptive transfer of Mϕin vivo (Mϕ from DN+MSCs mice) or MϕMSCs (Mϕ co‐cultured with MSCs in vitro) to DN mice improved renal function. While, TFEB knockdown in Mϕ significantly abolished the protective role of MϕMSCs. Altogether, these findings revealed that MSCs suppress inflammatory response and alleviate renal injuries in DN mice via TFEB dependent Mϕ switch.Support or Funding InformationThis work was supported by the National Natural Science Foundation of China (No. 81900666).
Comparisons of Nociceptive Behavior and NMDA receptor‐Mediated Synaptic Transmission between Mice Lacking D‐Serine Production and Degradation Enzymes
Authors: Kato Eiko , Saotome Toshiya , Yamaguchi Shigeki , Kansaku Kenji , Hori Yuuichi 
Published: April 2020

D‐serine is the endogenous co‐agonist for the glycine‐binding site of the N‐methyl‐D‐aspartate (NMDA) glutamate receptor. D‐serine is produced by the enzyme serine racemase (SR) and is degraded by the enzyme D‐amino acid oxidase (DAO). Co‐activation of spinal NMDA receptors by D‐serine is known to play a significant role in the etiological mechanism of neuropathic and inflammatory pain. The present study aims to obtain further information on how D‐serine and its related enzymes (SR and DAO) are involved in the modulation of persistent pain.The experiments were performed on both SR knock‐out (SR‐KO) mice and the DAO‐mutant mice that lack the enzymatic activity of DAO. We have previously shown that SR‐KO mice have less than half of the D‐serine content in the spinal cord and that DAO‐mutant mice have a significantly elevated level of D‐serine.The DAO‐mutant and SR‐KO mice used in this study are kindly provided by R. Konno (International University of Health and Welfare, Tochigi, Japan).First, the nociceptive behavioral responses to formalin that is subcutaneously injected into a hind paw were analyzed. Results showed that the responses in the second phase, which are known be associated with NMDA receptor activation, were augmented both in SR‐KO mice and in DAO‐mutant mice.Second, tight‐seal whole‐cell recordings were made from neurons in the superficial dorsal horn (SDH) in the lumbar spinal slices that were prepared from SR‐KO mice or from DAO‐mutant mice. Non‐NMDA and NMDA receptor‐mediated excitatory postsynaptic currents (non‐NMDAEPSCs and NMDA‐EPSCs, respectively) were pharmacologically isolated. Results show that the ratio of the amplitudes of NMDA‐EPSCs to that of non‐NMDA‐EPSCs was significantly smaller in SR‐KO mice and larger in DAO‐mutant mice compared with each corresponding control group and that the time constant of decay time course of NMDA‐EPSCs was significantly longer in SR‐KO mice.Finally, quantitative real‐time RT‐PCR experiments were performed on RNA extracted from the SDH tissue. The results showed that the subunit composition of NMDA receptors altered in SR‐KO mice and DAO‐mutant mice. The most significant observation is that the expression level of the NR2B subunit of NMDA receptors increased in the SR‐KO mice.These observations might indicate that D‐serine and its related enzymes (SR and DAO) influence the activation level of NMDA receptors and their subunit composition and thus affect nociceptive synaptic transmission in the SDH of the spinal cord and influence nociceptive behavior.Support or Funding InformationThis work was supported by JSPS KAKENHI Grant Number JP18K16462 (EK).
Exploration of the antidepressant‐like effect of repeated administration of Nigella fixed oil in rats
Authors: Kadil Youness , Tabyoui Imane , Badre Latifa , Tahiri Nadia Jouti , Filali Houda 
Published: April 2020

Due to the confirmation of the therapeutic properties of oils extracted from Nigella, and the constraints associated with antidepressant prescriptions, the reliance on phototherapy seems to be beneficial. The objective of the present paper is to investigate the behavioral effect of Nigella fixed oil, as well as exploring the histopathological impact on the structure of the hippocampus after exposure to the Unpredictable Chronic Mild Stress procedure in rats.Animals were randomly divided into five groups of eight. The stress procedure used in this study combines many stressful situations. These situations were randomly assigned with a frequency of two stressors per day throughout the 5‐weeks. Behavioral evaluation of antidepressant activity was based on the forced swimming test and histological evaluation of the hippocampus of rats with optical microscopy.Treatment by nigella and fluoxetine significantly reduces the struggling time during the test day of the forced swim test. Histopathological analysis showed that control treatments result in more loosely arranged cells, significant apoptotic neurons characterized by an irregular appearance, and pyknotic hyperchromatic. As well as a reduction in the thickness of the pyramid layer compared to the groups treated with nigella and fluoxetine.The results demonstrated the effect of Nigella in the forced swimming test, as well as the improvement of the pyramidal cell organization and neuronal degeneration. These data seem to be consistent with other studies, in which the neuroprotective properties of nigella refer to thymoquinone.
Characterization of the Troglitazone Induced Apoptosis in a Human Colon Cancer Cell Line
Authors: Przybelski Samantha , Ulloa Massiel E. , Rudie Melisa , Cornett Megan , Strom David 
Published: April 2020

Troglitazone (TRO), a peroxisome proliferator‐activated receptor (PPAR) agonist, was a drug used as an anti‐inflammatory and anti‐diabetic agent. PPARɣ specifically is a known member of the steroid receptor superfamily and is a ligand‐activated nuclear transcription factor that regulates lipid and glucose homeostasis. As a PPARɣ activator, TRO, a thiazolidinedione, has been shown to have the effect of inducing cell differentiation but also inhibiting cell growth, proliferation, and angiogenesis thereby facilitating apoptosis, making it a potential candidate to study as a cancer chemotherapeutic agent.Through the use of flow cytometry, TRO‐induced apoptosis of tissue culture grown colorectal cancer cells was examined. Apoptosis was quantified by analyzing cells that contain less than the 2N DNA content (one hallmark of apoptosis). A dose response curve was determined for increasing concentrations of TRO vs sub2N DNA content. These studies confirm that TRO was able to induce apoptosis in our cell lines at concentrations greater than 30mM.Next we examined which PPAR receptors subtypes are being activated by TRO. HCT116 cells were exposed to various concentrations of TRO for 24hr then RNA was isolated from these cells. Specific gene targets to each PPAR receptor subtypes were identified and using RT‐PCR, changes in mRNAs expression was examined. Targets for PPARdelta and PPAR gamma were consistently upregulated. We are working to refine these experiments to get better determinations on which receptors are activated by TRO.These experiments confirm that TRO induces apoptosis in HCT116 cells. Additionally, we have identified changes in at least one target of PPAR receptors in response to TRO exposure. Further experiments are needed to exactly determine which PPAR receptors are being activated by TRO, and whether the apoptosis medicated by TRO is a result of PPAR receptor activation.
Functional Characterization of X Antigen Genes (XAGEs)
Authors: Terrazas Sari , Ramanathan Saumya 
Published: April 2020

Cancer‐testis antigens (CTAs) are a group of genes that are normally expressed in the testis but aberrantly expressed in many different types of cancers. X‐linked antigens (XAGEs) are CTAs that are located on the X chromosome and that remain understudied and their role in cancer remains unclear. The specific expression of XAGEs in cancer cells make them a potential target for cancer therapy. The goal of this research project is to elucidate the biochemical function of XAGE genes and their protein products in normal and diseased states. We will first generate an atlas of cancer cell lines that display XAGE expression. Then we will perform gain and loss of function studies to determine what pathways are perturbed in the presence and absence of XAGEs. We will also determine binding partners of these proteins by IP‐Mass Spectrometry. In summary, our studies will shed light on the biochemical functions of the enigmatic XAGE proteins.Support or Funding InformationHRD1764201
Sex‐dependent Effects of High‐fat Diet and Stress on CNS Inflammation and Ceramides Production
Authors: Sambolin-Escobales Lubriel , Tirado-Castro Lizmarie , Fonseca-Ferrer Wilfred , Santos-Aviles Kimberly , Pacheco-Cruz Dariangelly , Colon Maria , Hernandez Anixa , Chompre Gladys , Porter James 
Published: April 2020

The intake of a high‐fat diet (HFD) and exposition to stress are associated with development of a neuroinflammatory state in the central nervous system (CNS). Previously we found high levels of long‐chain (C18:0 and C20:0) ceramides in blood of rats fed an HFD that correlated with increased immobility in the forced swim test, suggesting that ceramides could contribute to the development of depressive‐like behavior. In the current study, we aimed to determine whether adding short‐term unpredictable stress (STUS) would exacerbate the effects of HFD on neuroinflammation and ceramide metabolism in the ventral hippocampus (VH) and the development of depressive‐like behavior. We hypothesized that exposure to HFD and STUS would cause a neuroinflammatory state and increased levels of long‐chained ceramides in the VH leading to depressive‐like behavior. To test this, male and female Sprague Dawley rats were administered either a low‐fat or high‐fat diet for eight weeks, while other groups of female and male rats were administered a low‐fat or high‐fat diet for 10 weeks with the inclusion of 4 days of random unpredictable stressors. After sacrifice, we assessed the expression of microglial (Iba‐1), neuroinflammatory state (NLRP3, HMGB1 and TNF‐α) and ceramide production markers (CerS5, CerS6, SMPD1 and SMPD3) in the VH. Female HFD rats showed increased expression of TNF‐α and HMGB‐1 independent of STUS, while male rats increased expression of Iba‐1, TNF‐α and NLRP3 after exposition to STUS, suggesting a sex‐dependent activation of inflammatory mediators. The assessment of enzymes that produce long‐chained ceramides revealed increased CerS5, CerS6 and SMPD1 mRNA only in the VH of female HFD rats exposed to STUS, suggesting sex differences in the production of long‐chained ceramides due to combined HFD and STUS. VH tissue and blood were collected to quantify ceramides by gas chromatography‐mass spectrometry (GC‐MS). Based on the expression of the enzymes involved in the production of ceramides, we expect that the GC‐MS assay will show increased C16 ceramides in female rats exposed to HFD and STUS. After diet completion, rats were subjected to sucrose grooming test and forced swim test to assess anhedonia and behavioral despair. Female HFD with STUS showed trending increases in grooming activity, reduced immobility and increased swimming time while male rats did not present any behavioral changes, suggesting less depressive‐like behavior in female rats. In conclusion, an HFD in combination with STUS causes sex‐dependent changes inflammatory state and long‐chained ceramides production without increasing depressive‐like behavior.Support or Funding InformationNIH‐NIGMS R25GM082406 (PHSU RISE Graduate Training Program), U54 MD007579, NIGMS/INBRE P20 GM103475, and NIH‐NIGMS R25GM096955 (UPR‐Ponce PRISE Program).