bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biased agonists of the chemokine receptor CXCR3 differentially drive formation of Gαi and β‐arrestin complexes
Authors: Zheng Kevin , Smith Jeffrey S. , Choi Issac , Warman Anmol , Gundry Jaimee N. , Pack Thomas F. , Inoue Asuka , Caron Marc , Rajagopal Sudarshan 
Published: April 2020

G‐protein‐coupled receptors (GPCRs) are the most common cell surface receptor class and influence nearly every biological process within a cell. Approximately 30% of all FDA‐approved medications target GPCRs. Following receptor activation, G proteins and β‐arrestins are currently appreciated to be the two primary proximal intracellular signaling pathways that regulate GPCR signaling. It has been thought that G protein and β‐arrestin signaling pathways are largely discernable, evidenced in part by ‘biased agonists’ that can preferentially activate one of these pathways relative to the other. However, increased crosstalk between G protein and β‐arrestin pathways is beginning to be appreciated. We recently described the ability of Gα proteins to directly interact with β‐arrestins to form signaling scaffolds, with Gαi/o found to directly interact with β‐arrestin following GPCR activation regardless of canonical GPCR G protein coupling. We previously demonstrated in other work that all GPCRs tested, including the vasopressin type 2 receptor, β2‐adrenergic receptor, neurotensin receptor type 1, and the dopamine D1 and D2 receptors, formed a Gαi:β‐arrestin complex. Now that we appreciate this novel GPCR signaling paradigm, it is unclear if biased agonists that preferentially stimulate either G protein‐ or β‐arrestin‐dependent signaling differentially regulate Gαi:β‐arrestin interactions, if at all. To address this question, we utilized the chemokine receptor CXCR3 that binds three endogenous chemokines with high affinity. We demonstrate that these endogenous biased CXCR3 chemokines, CXCL9, CXCL10, and CXCL11, along with its synthetic biased agonists, VUF10661 and VUF11418, differentially form Gαi:β‐arrestin complexes. The ability of CXCR3 agonists to form Gαi:β‐arrestin complexes does not correlate highly with more well‐established GPCR signaling pathways including G protein recruitment, G protein signaling (e.g., regulation of cAMP), or β‐arrestin recruitment, suggesting that Gαi:β‐arrestin complex formation is distinct from conventional G protein or β‐arrestin signaling events. Additionally, differential Gαi:β‐arrestin complex formation was found to correlate with similar degrees of Gαi:β‐arrestin:CXCR3 “megaplex” formation, suggesting that formation of a long‐lived complex may depend upon close coupling of the two effectors at the receptor initially. This work provides further support for a separable Gαi:β‐arrestin signaling pathway and enhances our understanding of GPCR signaling and biased agonism.Support or Funding InformationNIH
The role of PHLPP in regulating mitochondrial dynamics in colorectal cancer
Authors: Hasani Sumati R. , Xiong Xiaopeng , Gao Tianyan 
Published: April 2020

Colorectal cancer (CRC) is the second leading cause of cancer deaths in men and women combined in the United States. According to the American Cancer Society, approximately 100,000 new CRC cases and 50,000 CRC‐related deaths are estimated in 2019. A better understanding of molecular mechanisms underlying tumor initiation and progression in CRC is urgently needed. We have shown previously that the PH domain leucine‐rich‐repeat protein phosphatase (PHLPP) family of phosphatases function as tumor suppressors by inhibiting several oncogenic signaling pathways, including the PI3K/Akt and RAS/RAF signaling. In our studies to determine the role of PHLPP in regulating cellular metabolism, we uncovered a novel link between PHLPP and Drp1, a member of the dynamin family of GTPases that plays a key role in regulating mitochondrial dynamics. Phosphorylation of Drp1 at S616 has been shown to increase its activity and induce mitochondrial fission. A number of protein kinases have been implicated in phosphorylating S616 site, however, how phosphorylation of Drp1 is regulated by phosphatases remains largely unknown. We found that knockdown of PHLPP increased, whereas overexpression of PHLPP decreased, the phosphorylation of Drp1 at S616, suggesting that PHLPP may negatively regulate Drp1 activity. As a consequence, increased levels of mitochondrial fragmentation were observed in PHLPP knockdown cells. Moreover, bioinformatics analysis of normal and tumor samples in TCGA dataset showed that the expression of Drp1 (DNM1L) gene is significantly increased in colon adenocarcinoma supporting a role of Drp1 in promoting tumorigenesis in CRC. Taken together, we identified PHLPP as a regulator of Drp1‐dependent mitochondrial fission. Results from our studies will provide novel insights into the functional significance of PHLPP‐mediated regulation of mitochondrial dynamics in CRC.Support or Funding Information5R01CA133429‐12 THE ROLE OF PHLPP IN COLON CANCER
IPA Software Analysis Reveals Inflammation and Apoptosis as Major Enrichment Functional Process in Normal Lung During Aging
Authors: Calyeca Jazmin , Balderas-Martinez Yalbi , Mora Ana , Selman Moises , Pardo Annie 
Published: April 2020

Aging is an irreversible biological process characterized by progressive functional decline and represent an independent risk factor for many chronic‐degenerative diseases. Several hallmarks have been associated to aging including genome instability, telomere attrition, epigenetic alterations, loss of proteostasis, deregulated nutrient‐sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, and altered cellular communication. In lungs, accelerated aging has been associated to some diseases such as idiopathic pulmonary fibrosis and chronic obstructive lung disease. However, the consequences of physiological aging on the lungs remain uncertain.In this study, we aimed to identify the dysregulated genes and pathways occurring in mice lung transcriptome during aging. For this purpose, lungs from 3 young (1‐month‐old) and 3 old (18‐month‐old) C57BL/6 mice were examined. We used Ingenuity Pathway Software analysis on a previous reported transcriptome evaluation performed in our Lab by Microarray technology (GeneChip™ Mouse Gene 2.0 ST Array of Affymetrix).In old lungs, 576 genes were differentially expressed compared with their young counterparts. In the top 10 upregulated pathways revealed by IPA analysis, the highest over‐expressed pathway in old WT lungs was the Triggering receptor expressed on myeloid cells‐1 (TREM‐1) followed by Toll‐like receptor (TLR) signaling and p38 MAPK. According to these findings, the expression of the upstream regulators INFγ, TNF, TLR2, and TLR4 were increased in the lungs of old mice. In addition, among the top five functions from the “diseases and disorders category” we found Respiratory Disease and Inflammatory Response as one of the higher enriched pathways. Finally, extended analysis of the top five functions from the “molecular and cellular functions category” reveals Cell Death and Survival, including Apoptosis of several lung cell populations, as one of the most enriched pathways.Support or Funding InformationSupported by CONACYT 281074
A human‐origin probiotic cocktail therapy for aging‐related leaky gut and inflammation by modulating microbiota‐taruine‐tight junction axis
Authors: Yadav Hariom , Ahmadi Shokouh , Wang Shaohua , Nagpal Ravinder , Wang Bo , Jain Shalini , Razazan Atefeh P. , Mishra Sidharth P. 
Published: April 2020

Inflammation is a major risk factor of morbidity and mortality in older adults. Although its precise etiology is unknown, low grade inflammation in older adults is commonly associated with increased intestinal epithelial permeability (leaky gut) and abnormal (dysbiotic) gut microbiota. The lack of treatments to reduce aging‐related microbiota dysbiosis, intestinal permeability and inflammation, and the increasing older population culminates on a rise in aging‐related comorbidities, constituting a significant public health concern. Here we demonstrated that a human‐origin probiotics cocktail containing 5‐lactobacilli and 5 enterococci isolated from infant gut, prevented high‐fat diet (HFD)‐induced microbiota dysbiosis, intestinal permeability, inflammation, metabolic dysfunctions and physical function decline in older mice. Probiotic‐modulated gut microbiota primarily reduced intestinal permeability by increasing tight junctions, which in turn reduced inflammation. Mechanistically, probiotic modulated microbiota in a way to increased bile salt hydrolase activity, which in turn increased taurine abundance in the gut that stimulated tight junctions and suppressed gut leakiness. Further, in Caenorhabditis elegans, taurine increased life span, reduced adiposity and intestinal permeability, and enhanced physical function. The results suggest that such probiotic therapy could prevent or treat aging‐related intestinal permeability and inflammation in elderly.Support or Funding InformationThis work was supported by funding from Department of Defense, National Institutes of Health and Wake Forest School of Medicine.
Elucidating the Role of Purinergic and Calcium Signaling During Rotavirus Infection
Authors: Engevik Kristen , Chang-Graham Alexandra , Engevik Melinda , Kellen Joseph , Perry Jacob L. , Hyser Joseph 
Published: April 2020

Calcium (Ca2+) is a ubiquitous messenger that influences numerous cellular processes, and therefore Ca2+ signaling is tightly regulated by cells. Ca2+ signaling dysregulation results in severe and potentially life‐threatening diseases, which is exemplified by rotavirus (RV) infection. RV is an enteric virus that causes life‐threatening diarrhea in children, resulting in ~198,000 deaths each year. While pathophysiological consequences of RV infection are widely studied, host Ca2+ signaling pathways and the mechanisms by which RV exploits them to cause diarrhea remain incompletely characterized. We have previously found that RV infection increases Ca2+ signaling both within infected enterocytes and in surrounding uninfected cells through paracrine signaling. This manifests as intercellular Ca2+ waves that originate from the infected cell and propagates to surrounding uninfected cells mainly through ADP activation of the P2Y1 receptor, which is expressed in many cell types in the intestine. We hypothesize that RV‐induced paracrine purinergic signaling functionally dysregulates neighboring uninfected enterocytes and modulates innate immune responses from both epithelial and intestinal immune cells. We generated cell lines and human intestinal enteroids (HIEs) stably expressing cytosolic genetically‐encoded Ca2+ indicators to characterize Ca2+ signaling throughout RV infection by time‐lapse imaging. We found that P2Y1‐mediated signaling was critical for activation of secretory epithelial cells, including induction of serotonin secretion of enterochromaffin cells and mucus secretion from goblet cells in human intestinal enteroids (HIEs) and mucin‐producing intestinal cell lines. Further, signaling from RV‐infected MA104 monkey kidney cells chemoattracted mouse bone‐marrow derived macrophages, which was blocked by pharmacological inhibitors of the P2Y1 receptor. Consistent with our in vitro findings, we observed that murine RV infection promoted secretion of serotonin, mucin and accumulation of macrophages. These effects of minimized in the presence of P2Y1 inhibitors and in P2Y1 knock out mice. Furthermore, we found that the RV‐induced increase in NFKb and IL‐1α are significantly attenuated by P2Y1 receptor blockers. Collectively these findings indicate that intercellular Ca2+ waves caused by paracrine purinergic signaling have a broad influence on intestinal pathophysiology during RV infection. Understanding the cellular consequences of P2Y1 activation during RV will generate new mechanistic insights into the homeostatic function of purinergic signaling in the GI tract.Support or Funding InformationR01 DK115507 (Hyser)T32 DK007664 (Engevik)
Elucidating the signaling pathways of CXCR4‐dependent chemotaxis.
Authors: Robleto Valeria Lucia , Zhuo Ya , Marchese Adriano 
Published: April 2020

Signaling by the G protein‐coupled receptor CXCR4 is essential to a number of developmental and physiological processes, including stem cell mobilization, organ development, and immune responses. In addition, CXCR4 signaling has been linked to disease, including cancer and immunodeficiency diseases. Despite its importance in health and disease, the mechanisms regulating CXCR4 signaling remain poorly understood. Typically, upon binding to its cognate ligand CXCL12, CXCR4 signaling occurs via G protein‐ and β‐arrestin‐dependent signaling pathways. Recently, our lab showed that β‐arrestin1‐dependent signaling is necessary for CXCR4‐mediated chemotaxis. However, this signaling pathway remains poorly understood. With this in mind, we performed proximity labeling by ascorbic acid peroxidase (APEX2) fused to β‐arrestin1 in order to identify proteins that are part of the β‐arrestin1 interaction network downstream of CXCR4. Labeled proteins from cells treated with vehicle or CXCL12 for 5 or 60 minutes were selectively purified and identified by mass spectrometry. Several proteins of biological relevance were identified and predicted to be part of the β‐arrestin1 interaction network downstream of CXCR4. One of these proteins was selected for further analysis and shown to interact with β‐arrestin1 by glutathione S‐transferase pull down experiments. The goal of this project is to provide further evidence that this protein is indeed part of the β‐arrestin1 interaction network and to determine its role in CXCR4 signaling. This will be accomplished by using cell culture model systems coupled with several approaches, including biochemical, molecular, RNA interference, fixed and live cell confocal microscopy techniques and chemotaxis studies.Support or Funding InformationGran Number 10672706A1
Cognitive function during passive heat exposure is not affected by short‐term heat acclimation
Authors: Barry Hadiatou , Gendron Philippe , Behzadi Parya , Gravel Hugo , Gagnon Daniel 
Published: April 2020

INTRODUCTIONHyperthermia affects cognitive performance, particularly decision‐making, the speed of performing a task and the ability to perform complex tasks. Cognitive performance is generally thought to be impaired by hyperthermia, although a u‐shaped relationship may exist between the level of hyperthermia and cognitive performance. Few studies have examined potential strategies to alter the relationship between hyperthermia and cognitive performance. Heat acclimation improves the physiological responses to heat exposure, but its effects of cognitive function remain understudied. The purpose of this study was to evaluate how cognitive performance during acute heat stress is modulated by short‐term heat acclimation.METHODSEight healthy adults (25 ± 4 years, 4 women/4 men) participated in the study. Participants first underwent either (n=6) a 7‐day controlled hyperthermia protocol (internal body temperature ≥38.6°C for 60 minutes) or (n=2) a 7‐day time‐control period. After a minimum 1‐week washout, participants crossed‐over to the other condition. On days 1 and 7, participants performed a digital Stroop test to evaluate their response time to reading, counting, inhibition and overswitch tasks at baseline and after 60 minutes at an internal body temperature ≥38.6°C or after a 60‐minute time‐control period.RESULTSOn day 1 of the control condition, reaction time during reading (−6 ms [−31, 19], p=0.79), counting (11 ms [−21, 42], p=0.66), inhibition (−31 ms [−95, 34], p=0.44) and overswitch (−38 ms [−82, 6], p=0.09) tasks was not acutely affected by a 60‐minute time‐control period. On day 1 of the heat acclimation protocol, internal body temperature (39.00 ± 0.17°C, p<0.01), mean skin temperature (37.66 ± 0.55°C, p<0.01) and heart rate (110 ± 11 bpm, p<0.01) were greater during the cognitive tasks performed under heat stress. Heat exposure acutely improved response time during reading (−56 ms [−81, −31], p<0.01), counting (−57 ms [−89, −26], p<0.01), inhibition (−84 ms [−149, −20], p=0.01) and overswitch (−68 ms [−113, −24], p<0.01). However, heat acclimation did not affect cognitive performance during each of the cognitive tasks as determined from 3‐way interactions (time × condition × day) for reading (p=1.00), counting (p=0.73), inhibition (p=0.09) and overswitch (p=0.70).CONCLUSIONSThese results suggest that heat exposure acutely improves reaction time during reading, counting, inhibition and overswitch cognitive tasks, but that this improvement is not affected by 7 days of heat acclimation.Support or Funding InformationNatural Sciences and Engineering Research Council (RGPIN‐2017‐04243)
LEW.1WR1 Rats have increased insulin levels and liver lipid lipolytic gene expression during their type 1 diabetes susceptibility window.
Authors: Wimalarathne Madushika M. , Wade Amber M. , Love-Rutledge Sharifa 
Published: April 2020

LEW.1WR1(1WR1) rats have increased type 1 diabetes (T1D) onset with the administration of polyinosinic‐polycytidylic acid (PIC). The susceptibility window of inducible T1D in the 1WR1 rat occurs between 21–35 days of life. The susceptibility of this model is related to FAT10 overexpression, a ubiquitin‐like protein that plays an unclear role in disease induction and the regulation of lipid metabolism. We hypothesized that these rodents have altered liver lipid metabolism due to increased FAT 10 gene expression in their livers and increased circulating insulin levels which can lead to decreased liver insulin sensitivity and increased beta‐cell sensitivity to inflammation. The objective of this study was to compare the insulitis status and liver gene expression in both control and treated 1WR1 rats during disease induction with a T1D‐resistant strain of rat, the LEW/SSNHsd.Using immunohistochemistry we observed higher T cell infiltration in the 1WR1 treated rats compared to the control strain, the LEW/SsNHsd(SsNHsd) PIC‐treated rat. By correlating plasma glucose levels measured by glucometer with this finding we confirmed that the 1WR1 rats were not undergoing significant insulitis at the time point we selected. We also observed that the rats have significantly fewer total islets than the SsNHsd rats but remained normoglycemic. Interestingly the 1WR1 treated rat had significantly increased insulin levels compared to the SsNHsd rats, as previous studies showed a 3 fold increase in the 1WR1 rat compared to Wistar Furth rats in a similar study(unpublished data). Both groups of the 1WR1 rats also had increased liver FAT10 gene expression compared to the SsNHsd. We measured liver lipid lipolytic gene expression to assess the metabolic status of the livers at this time point. We observed 1WR1 rats have increased expression of genes related to lipid catabolism like SREBP‐1 (Sterol Regulatory Element‐binding Protein‐1), ATGL (Adipose triglyceride lipase), DGAT1(diacylglycerol acyltransferase‐1), DGAT2(diacylglycerol acyltransferase‐2) and lower expression of glucose metabolism‐related genes like GLUT2(Glucose transporter 2), suggesting that the 1WR1 rats may have had a liver sensitivity response to the hyperinsulinemia. In conclusion, 1WR1 rats have reduced insulin sensitivity in the context of increased inflammation due to PIC injection which led to beta‐cell sensitivity and eventual T‐cell mediated destruction.Support or Funding InformationDepartment of Chemistry, UAHDepartment of Biology, UAHCollege of Science, UAHOffice of Provost, UAH
The Activation of Macrophage Scavenger Receptors through the Phosphorylation Cascade Generated by Nanomolar Cadmium Doses
Authors: Kumar Wasan Mani , Ribeiro Marta , Balla Andre Kajdascy 
Published: April 2020

Nanomolar cadmium concentrations have been shown to increase the risk for atherosclerosis and promote endothelial damage. Atherosclerotic plaque formation is regulated by scavenger receptors, which are cell surface receptors crucial to macrophage apoptosis and foam cell formation. LOX‐1, CD‐36, and SR‐A I/II are the main macrophage and endothelial receptors responsible for internalization of oxidized LDL.Incubation with CdCl2 caused a four‐fold increase in LDL absorption by RAW 264.7 (murine) macrophages. To study mechanisms of this increase, macrophages were treated with 2 mg/ml of LDL only, 5nM to 200 nM CdCl2 and then both treatments combined, all for a 48 hour period. Cell lysates were then subjected to a phospho‐kinase array, which simultaneously analyzes the rate of phosphorylation for 43 kinases. When exposed to 10 nM CdCl2, Signal Transducer and Activator of Transcription 5 (STAT5) had a 5 fold increase in phosphorylation compared to control (macrophage cells only), which was the highest in the array. 30 kinases had a significant increase in phosphorylation, while 13 kinases showed a significant decrease in phosphorylation, the greatest decrease being p53 which was knocked down to half. Interestingly, the cadmium induced changes in phosphorylation were attenuated by LDL co‐incubation.In vitro studies were performed to assess levels of LOX‐1, CD‐36 and SR‐A I/II. Macrophage cells were exposed to 200 nM CdCl2, STAT5 inhibitor AC‐4‐130, and 2 mg/ml of LDL for 48 hrs. Lysates were assessed for scavenger receptor expression by ELISA assay. Both the 200 nM CdCl2 and STAT5 inhibitor groups showed significantly increased expression of all 3 scavenger receptors, and the 200 nM CdCl2 STAT5 inhibitor combination resulted in an even higher fold expression.Overall, cadmium plays a role in the progression of atherosclerosis which could in part be via the phosphorylation cascade. STAT5 inhibits the transcription of CD36, hence the increased expression of CD36 and other scavenger receptors noted in the presence of a STAT5 inhibitor. However, cadmium increases the phosphorylation and subsequent function of STAT5 while also increasing the expression of CD36, LOX‐1 and SR‐A I/II. This implies a non‐STAT5 mediated mechanism. It would be interesting to examine the function of the other cadmium‐modulated highly phosphorylated or dephosphorylated kinases in scavenger receptor expression.
Characteristics of the substrate‐free mitochondria
Authors: Leem Chae Hun , Ho Quynh Mai , Lee Jeong Hoon , Kim In Young , Youm Jae Boum 
Published: April 2020

Mitochondria are critical organelle to convert the metabolites to the life‐essential chemicals, ATP. For serving the role, the mitochondria have very peculiar steps from metabolites to ATP formation. Usually the Ψm was regarded as zero without the mitochondrial substrate or in the presence of uncoupler. However, we found there still considerable Ψm was existed even in those conditions. So basic scheme of the generation of Ψm is hampered and the question how to explain this phenomena remains. For attacking these problems, we used a multiparametric microfluorometric system to monitor NADH, FAD, and TMRE fluorescence, simultaneously and developed a measurement method of Ψm quantitatively. The Ψm in substrate free conditions was around −60 mV. The application of ATP generated considerable hyperpolarization. The application of KATP channel opener, diazoxide (DZX), could depolarize Ψm. When K+ was replaced with meglumin, the Ψm was slightly hyperpolarized and the effect of DZX was abolished. The KATP channel blockers did not have any effect. The application of ATP hyperpolarize Ψm, however, ADP or AMP didn’t. Oligomycin blocked the effect of ATP. Interestingly, oligomycin depolarized the resting Ψm considerably. The effect of ATP was not affected by DZX. The replacement K+ with meglumin slowed the ATP‐induced change of Ψm and made it transient. The return to K+ medium recovered the effect of ATP. From these results, the Ψm in substrate‐free conditions was not zero and K+ may particpate in the formation of the resting Ψm. The F1,F0‐ATPase may participate on the formation of the resting Ψm. K+ may be an important modulator for F1,F0‐ATPase acitivity. The F1,F0‐ATPase and K+ flux might contribute the formation of the resting Ψm but it still need further study on them.Support or Funding InformationThis work is supported by NRF‐2015M3A9B6028310 and NRF‐2016M3C1A6936605.