bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strain‐Dependence in Susceptibility to Heart Failure: Role of Mitochondria
Authors: Ascah Alexis , Marcil Mariannick , Matas Jimmy , Oliver‐Dussault Christelle , Deschepper Christian , Burelle Yan 
Published: June 2021

The purpose of this study was to compare two genetically different strains of rats submitted to overload‐induced ventricular remodelling to examine factors that predispose to the progression toward heart failure. Volume overload was induced by an aorto‐caval fistula (ACF) in SD and WKHA male rats, and hearts were studied at 4, 8 and 12 weeks after surgery. Compared to WKHA, ACF‐induced LV hypertrophy and dysfunction progressed more rapidly in SD rats, and functional recovery of SD hearts to I‐R was poorer vs WKHA during the compensated phase of disease. At later times (up to 40 weeks after ACF), SD rats (but not WKHA rats) died progressively of acute cardiac decompensation. Both strains developped a vulnerability to opening of the PTP, as measured in situ (in ischemic‐reperfused hearts using the mitochondrial [3H]DOG entrapment method) or in isolated mitochondria submitted to in vitro stress. Increased vulnerability to PTP opening was observable beginning at 4 weeks but no differences in severity was apparent between strains. The % of collagen‐cross linking increased progressively after ACF in both strains, but to a lower extent in SD vs. WKHA hearts. These results suggest that, while mitochondrial dysfunction may participate to the negative consequences of ACF‐induced LVH in both strains, it is not responsible for the more the rapid progression to decompensation observed in SD rats. Further experiments are underway to test the differences in cardiac outcome may be due to differences in the levels of collagen‐cross linking.Funded by: CIHR, FRSQ
In vitro and in silico experiments to identify the influence of temperature on skeletal muscle calcium and force dynamics
Authors: Groenendaal Willemijn , Jeneson Jeroen , van Riel Natal , Eikelder Huub ten , Nicolay Klaas , Hilbers Peter 
Published: June 2021

Temperature has been shown to influence skeletal muscle performance. To be able to understand and quantify the influence of temperature on local calcium and force dynamics, in vitro and in silico experiments were performed in mouse EDL.The spatiotemporal model of Baylor and Hollingworth (J Gen Physiol. 1998 112:297–316) was adapted in such a way that it was able to describe local calcium dynamics in EDL at different temperatures. Most processes in the sarcomere were temperature dependent and were scaled with Q10 values based on literature. Model simulations were performed for a stimulation frequency of 1–10–30–60–90–120 Hz and muscle temperatures of 15–20–25–30–35C. In parallel, the mechanics of isometric contractions of isolated mouse EDL were measured for the same conditions as the simulations (ter Veld et al. 2006 Pflugers Archiv 452: 432–8).For increasing muscle temperatures, shorter rise and decay times of the Ca2+ pulse were predicted by the model. Similar trends were obtained for the rise and decay time of the measured force. For increasing stimulation frequency, the model predicted an increase in baseline and maximal Ca2+ concentration, while the measurements showed similar trends for the produced force. On top, the experiments showed that stimulation frequency influenced the decay rate at 35C.Furthermore, the experiments will be used to validate Q10 values in the model as well as the total amount of Ca2+.
Evidence that NBCe1‐A Monomers are Functional
Authors: Azimov Rustam , Abuladze Natalia , Kao Liyo , Pushkin Alexander , Newman Debra , Liu Weixin , Kurtz Ira 
Published: June 2021

Previous studies from our laboratory have shown that the oligomeric structure of NBCe1‐A is predominantly a dimer. We also demonstrated that oligomerization of NBCe1‐A is absolutely dependent on S‐S bond formation. Whether NBCe1‐A monomers are functional is currently unknown. To address this question, we took advantage of our recent finding that the NBCe1‐AT442C mutant functions normally but can be completely inhibited by the MTS reagents MTSEA, MTSES, and MTSET. In contrast these agents have no effect of wt‐NBCe1‐A. The following concatameric constructs of wt‐NBCe1‐A and NBCe1‐AT442C were studied: wt‐NBCe1‐A‐linker‐wt‐NBCe1‐A; wt‐NBCe1‐A‐linker‐NBCe1‐AT442C; NBCe1‐AT442C‐linker‐wt‐NBCe1‐A; and NBCe1‐AT442C‐linker‐NBCe1‐AT442C. The length of the linker varied inversely with the baseline concatamer function, and concatamers with the shortest linker (Thr‐Gly) functioning optimally. Flux through the four concatamers was measured in HEK‐293T cells using BCECF and quantitating the cell buffer capacity. Non‐denaturing gel electrophoresis demonstrated that each of the four concatameric constructs is monomeric. The function of the four concatamers was similar to wt‐NBCe1‐A and NBCe1‐AT442C. In the presence of the MTS reagents MTSES and MTSET, the function of both mixed‐concatamers was decreased to 40–53% of normal. The function of the wt‐NBCe1‐A homo‐concatamer was unaffected, whereas both reagents blocked the function of the mutant NBCe1‐AT442C homo‐concatamer. Our results demonstrate that the NBCe1‐A monomer is functional.Supported by the NIH
NMR structural characterization of the homodimerization domain of the translational repressor GLD‐1
Authors: Beuck Christine , Szymczyna Blair , Columbus Linda , Williamson James 
Published: June 2021

GLD‐1 is a prototypical member of the STAR class of proteins, which are highly conserved among higher eukaryotes and seem to play a general role in posttranscriptional gene regulation. In the C. elegans hermaphrodite germ line, GLD‐1 is essential for inducing meiosis. Furthermore, it triggers the spermatogenesis‐to‐oogenesis switch by regulating the differentiation of germ line stem cells. GLD‐1 translationally represses the expression of proteins promoting oogenesis by binding to the 3′ untranslated region of their messenger RNAs (mRNAs). GLD‐1 homodimers recognize 28 nucleotide repeats within the mRNA. Each repeat can accommodate one GLD‐1 dimer.Even though the structures of a few homologous STAR protein RNA binding subdomains have been determined, no structural information is available on the homodimerization subdomain. Our structural characterization of the GLD‐1 homodimerization domain by CD, NMR and EPR spectroscopy points towards a α‐helical, antiparallel coiled‐coil dimeric structure.
Analysis of transcription and protein changes in response to human RET activation in SKN‐SH and transfected COS cells.
Authors: Torres Martha Angelina , Poku Maryann , Vega Quinn 
Published: June 2021

RET is a mammalian receptor tyrosine kinase normally activated after association with a protein co‐receptor GFR‐a (1–4) and its corresponding ligand (GDNF, Neurturin, Artemin or Persephin). RET is required for nervous system development and RET mutations are associated with both cancer (MEN2A, MEN2B and FMTC) and developmental abnormalities (Hirschsprung's Disease). In order to analyze how the cell responds to RET activation, isoform expression, internalization and downstream transcription were measured in RET expressing cells. QPCR was used to measure the production of the two major isoforms of RET‐RET9 and RET51. In these experiments, RET 9 levels increased ∼ 4‐fold in comparison to RET 51. With respect to internalization, the loss of RET was identified over time with a loss of the RET protein by 6 hours. With respect to signaling, downstream luciferase promoter assays demonstrated that wild type RET increased transcription over phosphotyrosine mutants and kinase inactive RET. Future experiments will confirm these changes and study the effect of both specific tyrosines and naturally occurring mutations on RET signaling.(Supported by NIH Grant R15‐NS048043)
Identification of age‐related changes in both hematopoietic progenitors and thymic stromal components contributing to thymopoietic capacity
Authors: Thoman Marilyn Louise 
Published: June 2021

Thymopoiesis dramatically decreases with age. Hematopoietic progenitors as well as the thymic structural cells undergo functional alterations with age. To dissect the contribution of each of these thymic components to the overall process of involution, a series of bone marrow‐irradiation chimeras were constructed in which either young or aged host mice were reconstituted with bone marrow progenitors derived from young or aged donor mice. Both donor type progenitors are equal in reconstituting young host thymuses as measured by total cellularity. In contrast, the aged thymic environment was less well reconstituted by either type donor. Further the aged bone marrow was less effective than the young‐derived progenitors in this environment. Specifically the thymus in an aged host reconstituted with young bone marrow progenitors was 4 fold larger than that reconstituted with aged bone marrow. This size differential was found from 4–24 weeks post transplant. Subset analysis further reveals that the aged progenitors within the aged thymic microenvironment are deficient in the production of mature CD4 and CD8+ T cells. In competitive repopulation assays, aged progenitors are clearly deficient. Together the results indicate that interaction with young thymic stromal elements overcomes at least some age‐associated functional deficiencies in T cell progenitors.Support NIH RO1AG09948 and RO1AG028077 to MLT
Tristetraprolin down‐regulates E47 mRNA stability in old splenic murine B cells
Authors: Blomberg Bonnie B , Landin Ana Marie , Alvarez Juan P , Riley Richard L , Frasca Daniela 
Published: June 2021

The E2A‐encoded transcription factor E47, which regulates class switch recombination (CSR) in splenic B cells, is down‐regulated in aged murine B cells, due to increased E47 mRNA decay. We have previously shown that part of the decreasedstability of E47 mRNA seen in aged B cells is mediated by tristetraprolin, TTP, which binds AU‐rich elements in the 3′‐untranslated region (3′‐UTR) of mRNAs leading to their rapid degradation. Levels of TTP are higher and phosphorylation of TTP is lower in old B cells than in young B cells, generating more mRNA degradation. The pro‐B cell line 107.2 transfected with the TTP‐siRNA suppressed TTP and led to enhancedaccumulation of E47 mRNA. These results altogether suggest that TTP plays a relevant role in the degradation of E47 mRNA and in the control of CSR and somatic hypermutation of Ig, critical for high affinity Ig and optimal response to pathogens. We have also introduced the coding region of E47 (lacking the 3′‐UTR) by retroviral transduction of young and old splenic activated B cells. This over‐expression of E47 up‐regulated activation‐induced cytidine deaminase and CSR in both young and old, restoring the old levels to that of normal young levels.This work is supported by NIH AG‐17618, AG‐23717 (BBB) and AG025256 and AI064591 (RLR)
Salmonella enterica serovar Typhimurium Induces Rapid Migration of Dendritic Cells into the Gut Lumen
Authors: Bertelli Eugenio , Regoli Marì , Clare Simon , Hautefort Isabelle , Hinton Jay , Ivory Kamal , Nicoletti Claudio , Arques Juan 
Published: June 2021

Dendritic cells (DC)s are key elements for the immune responses and can operate as antigen sampling cells. We report now that they can also migrate into the gut lumen upon bacterial challenge. Isolated intestinal loops in BALB/c mice, C57/BL6 and C57/BL6 MyD88 knock out (KO) mice were infected with non invasive GFP‐labelled S. Typhimurium strain SL1344 (?SPI1, rpsM‐gfp), a derivative of the same strain lacking SPI1 and both fliC and fljB flagellin encoding genes, E. coli DH5a (/pZEP16, rpsM‐gfp), or PBS. After three hours, luminal content was harvested, washed and DCs were separated. FACS was carried out to characterize and enumerate the recovered cells. Confocal microscopy (CM) and TEM were also performed.Approximately 7 × 104 cells were present in loops treated with flagellated S. typhimurium SL1344, but not in loops belonging to the C57/BL6 MyD88 KO mice. Phenotypic analysis showed the presence of CD11c+, CX3CR1+, MHCII+, CD8a− and CD11b− cells associated with Salmonella. CM confirmed the increase of CD11c+ DCs in the gut lamina propria. TEM and CM showed bacteria associated with luminal DCs. These data show that Salmonella induces flagellin‐ and Toll‐like receptor‐dependent DC migration into the gut lumen.
A linkage disequilibrium block from the BRCA1 gene was associated with breast cancer in Korean population
Authors: Kim Kyoung‐Yeon , Lee Seung Ku , Kim Hyoun Geun , Kang HyunJun , Kim Jeong‐Geun , Oh Ah Reum , Pyun Jung A , Kim Min‐Ho , Kang Eun Joo , Won SeongSik , Kang Jason J. , Yang Song‐Ju , Noh Dong‐Young , Han Wonshik , Kwack KyuBum 
Published: June 2021

Recently, the morbidity and mortality of breast cancer have markedly increased in Korea. Many studies were performed to find the genetic susceptibility genes that might be involved in oncogenesis and treatment of breast cancer in various ethnic populations. Among the susceptible genes, the BRCA1 and BRCA2 genes have been shown to be involved in hereditary breast cancer.To identify whether the polymorphisms in these genes are associated with breast cancer, genetic association study was performed for tag single nucleotide polymorphisms (SNPs) located in the BRCA1 and BRCA2 genes with 346 breast cancer patients and 361 healthy controls in Korean ethnic group. We could not find any significant associations between SNPs in BRCA1 and BRCA2 genes and breast cancer. A single linkage disequilibrium (LD) block from the BRCA1 gene, however, was significantly associated with breast cancer. The haplotype (ht1) of this LD block was increased the risk of breast cancer (OR=0.584, p=0.039) and haplotype (ht2) revealed a protective effect (OR=1.272, p=0.027).According to the premise of LD and previous reports, we hypothesized that any causative or protective variants contribute to or against breast cancer may exist in this LD block. In this presentation, possible causative variations in ht 1 and ht 2 will be discussed.
Cross‐talk between Angiotensin II and IGF‐1‐induced connexin 43 expression in human saphenous vein smooth muscle cells involving αvβ3 integrin clustering and activation of focal adhesion kinase
Authors: Aggarwal Himanshu , Jia Guanghong , Cheng Gang , Agrawal Devendra K. 
Published: June 2021

Vascular restenosis following coronary artery bypass grafts is a major clinical complication due to intimal hyperplasia in venous conduits. However, the precise underlying mechanisms of intimal hyperplasia are still unclear. We have recently reported that increased expression of connexin43 (Cx43) is involved in the proliferation of vascular smooth muscle cells (VSMCs) in human saphenous vein (SV). In this study, we investigated the signaling transduction pathway involved in Cx43 expression and SV SMC proliferation. Angiotensin‐II (AT‐II, 100ng/ml) increased AT‐1R mRNA expression and IGF‐1 (100ng/ml) upregulated IGF‐1R mRNA expression in SV SMCs. Interestingly, AT‐1R expression was also increased by IGF‐1 treatment and IGF‐1R expression was increased by AT‐II treatment. Both AT‐II and IGF‐1 significantly induced the expression of αvβ3 integrin and downstream activation of FAK in SV SMCs. AT‐II and IGF‐1 also significantly induced the expression of Cx43 in SV SMCs. The effect of AT‐II and IGF‐1 on Cx43 expression was attenuated by AT‐1 receptor antagonist, Losartan, IGF‐1R blocking antibody and αvβ3 integrin antibody. These data demonstrate a cross‐talk between IGF‐1R and AT‐1 in AT‐II and IGF‐1‐induced Cx43 expression in SV SMCs involving αvβ3 integrin clustering and downstream activation of FAK signaling pathway.(Supported by a grant from the NIH R01HL07349)
Differential Bone Marrow Stem Cell Mobilization by G‐CSF Injection or Arterial Ligation in Baboons
Authors: Shi Qiang , Wang Xingli , VandeBerg John L. 
Published: June 2021

In the current study, we investigated whether G‐CSF‐mobilized BMSCs share the same subtype profiles as the ischemia‐induced repair in nonhuman primate baboons.Methods and Results: We subjected 5 baboons to femoral artery ligation and 5 baboons to subcutaneous G‐CSF injection. Blood BMSCs were measured by surface antigens; functional differentiation to endothelial cells was assessed by colony forming capacity, expression of mature endothelial cell antigens and tube‐like formation. The blood CD34+ cells were spiked on day 3 post‐stimulation in both groups. While CD34+ cells released by artery ligation was 2‐fold lower than those by G‐CSF administration, significantly more CD133+/KDR+/CXCR4+/CD31+ cells were detected in baboons with artery ligation. After culture in endothelial growth medium, mononuclear cells from baboons with artery ligation formed more endothelial cell colonies (p < 0.05), formed more capillary‐like tubes (p < 0.05), expressed higher vWF and phagocytosed more Dil‐LDL (p < 0.05).Conclusions: While G‐CSF and artery ligation can mobilize BMSCs capable of differentiating into endothelial cells, BMSCs mobilized by the artery ligation simulating in vivo ischemic attacks have higher potential for vascular differentiation. Our findings suggest that direct bone marrow aspiration may provide the pool of BMSCs capable of transforming into mature cardiovascular cells.
Serotonergic involvement in the effects of chronic cold stress on reversal learning in the rats
Authors: Lapiz‐Bluhm M. Danet , Soto‐Pina Alexandra , Morilak David 
Published: June 2021

Chronic stress is a risk factor and an antecedent to depression and to dysregulation of brain modulatory systems. Chronic intermittent cold (CIC) stress sensitized the increase in norepinephrine (NE) release in hippocampus and medial prefrontal cortex (mPFC) in response to acute stress (Mana & Grace, 1997. Neuroscience 81:1055). Cognitive performance in an attentional set‐shifting task (AST) can be enhanced by tonic NE transmission in mPFC (Lapiz & Morilak, 2006. Neuroscience 137:1039), and is disrupted by chronic unpredictable stress (Bondi et al. 2007. Neuropsychopharmacol. e‐pub). This study addressed the effects of CIC stress on performance of rats in the AST. Male Sprague‐Dawley rats exposed to a 4°C cold room (6 hr/day × 14 days) were tested in the AST. Analyses showed a significant effect of Stress (P = 0.043), Task (P < 0.0001) and a Stress × Task interaction (P = 0.001), with CIC‐stressed rats requiring more trials during reversal 1. The orbitofrontal cortex (OFC) has previously been implicated in reversal tasks, possibly modulated by serotonin (5‐HT). We showed that 5‐HT depletion with Para‐chlorophenylalanine (200 mg/kg/day, i.p.) induced a similar selective deficit in reversal, while the CIC‐induced impairment in reversal learning was attenuated by the 5‐HT reuptake inhibitor (SSRI) Citalopram (5 mg/kg, i.p.). These results indicate that the CIC stress‐induced impairment in cognitive flexibility may involve an alteration in 5‐HT function in OFC. These deficits may be relevant to the symptoms of neuropsychiatric disorders that respond to SSRI treatment, i.e., depression and anxiety disorders.Support: NIMH grant MH72672 & NARSAD Award to MDLB
Peptide Ligands of Regulator of G‐Protein Signaling 4 (RGS4) Identified from a One‐Bead, One‐Compound LIbrary
Authors: Roof Rebecca A. , Clements Samuel , Roman David L. , Sobczyk‐Kojiro Katarzyna , Turbiak Anjanette , Mosberg Henry I. , Neubig Richard R. 
Published: June 2021

RGS proteins accelerate the hydrolysis of GTP by the Gα subunit of the heterotrimeric G‐protein and therefore quicken the inactivation of G‐protein signaling. The distinct expression patterns and pathophysiologic regulation of RGS proteins suggest that inhibitors of their activity may have therapeutic potential.The objective of this study is to identify peptide inhibitors of RGS4. We synthesized a focused One‐Bead, One‐Compound peptide library that retains structural features known to be necessary for the activity of a previously identified peptide. The library of 2.5 million peptides was screened and peptide‐beads with increased binding to a fluorescently labelled RGS4 were isolated. One of these hit peptides (9, Tyr‐Trp‐[Cys‐Lys‐Leu‐Cys]‐Lys‐NH2, S‐S) blocked the interaction between biotin‐RGS4 on avidin beads and a fluorescent Gαo with an IC50 of 28 μM in a Flow Cytometry Protein‐Protein Interaction Assay. It had RGS selectivity with the following order of inhibition RGS4>RGS8>RGS16≫RGS19>RGS7. Surprisingly, inhibition of RGS4 was irreversible. A methylene dithioether bridged peptide did not inhibit RGS4/Gαo interactions, suggesting that peptide 9 was forming a disulfide bond to RGS4. Future directions include determining which cysteine in the RGS is modified using mutagenesis and mass spectrometry. Supported by 5R01DA003910‐21 to HIM.
PI(3,4,5)P3 Potentiates Phospholipase C‐[beta] Activity
Authors: Zhang Yong , Kwon Sun Hyung , Vogel Walter , Filtz Theresa 
Published: June 2021

Phospholipase C‐[beta](PLC‐[beta]) isozymes are key effectors in G protein‐coupled signaling pathways. Previously, we had shown that PLC‐[beta]1 and PLC‐[beta]3 bound immobilized PIP3. In this study, PIP3 was found to potentiate Ca2+‐stimulated PLC‐[beta] activities using an in vitro reconstitution assay. LY294002, a specific PI 3‐kinase inhibitor, significantly inhibited 10 minutes agonist‐stimulated total IP accumulation. Both LY294002 and wortmannin inhibited 90 seconds agonist‐stimulated IP3 accumulation in intact cells. Moreover, transfected p110CAAX, a constitutively activated PI 3‐Kinase catalytic subunit, increased 90 seconds oxytocin‐stimulated IP3 accumulation. Receptor‐ligand binding assays indicated that LY294002 did not affect G protein‐coupled receptors directly, suggesting a physiological role for PIP3 in directly potentiating PLC‐[beta] activity. When co‐expressed with p110CAAX, fluorescence‐tagged PLC‐[beta]3 was increasingly localized to the plasma membrane. Conversely, a greater proportion of PLC‐[beta]3 associated with cytosolic fraction following H9c2 cells treatment with LY294002. Additional observations suggest that the PH domain of PLC‐[beta]1 and ‐[beta]3 is not important for p110CAAX‐induced membrane association.This work was supported by a grant from the NIH R01‐GM61244 (to T.M.F.).
Identification of the site on p90 RSK1 that binds the catalytic subunit of PKA
Authors: Gao Xianlong , Chaturvedi Deepti , Patel Tarun 
Published: June 2021

Previously, we reported novel interactions between subunits of cyclic AMP‐dependent protein kinase (PKA) and ribosomal S6 kinase 1 (RSK1). The interactions are dependent upon the activation state of RSK1, with inactive RSK1 associating with the type I regulatory subunit (RI) of PKA whereas active RSK1 binds with the catalytic subunit of PKA (PKAc). Through these interactions, PKA modulates the subcellular localization of RSK1 and thereby its anti‐apoptotic effects. Here we report the identification of the regions of RSK1 that are responsible for the interaction with PKA. We expressed several polypeptides of full‐length RSK1 (aa 1–735) in Hela cells and performed immunoprecipitation with anti‐PKAc antibody. RSK1‐NT (aa 1–317), which contains the N‐terminus kinase domain (NTK) of RSK1, was not co‐precipitated with PKAc, whereas RSK1‐LCT (aa 318–735), which includes the linker region and C‐terminus kinase domain of RSK1, was co‐precipitated with PKAc. Subsequently, we tested RSK1‐NT+Linker (aa 1–418), RSK1‐CT (aa 418–735) and RSK1‐CTK (aa 418–671). RSK1‐CT, but not RSK1‐NT+Linker or RSK1‐CTK, was co‐precipitated with PKAc, indicating that the extreme C‐terminus of RSK1 (aa 671–735) is crucial for the interaction with PKAc.Supported by NIH grant GM 079226