The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Thomas M Kinfe - One of the best experts on this subject based on the ideXlab platform.

  • unilateral l4 dorsal root ganglion stimulation evokes pain relief in chronic neuropathic postsurgical knee pain and changes of inflammatory markers part ii whole transcriptome profiling
    Journal of Translational Medicine, 2019
    Co-Authors: Thomas M Kinfe, M Asif, Krishnan Chakravarthy, Timothy R Deer, Jeffery M Kramer, Thomas L Yearwood, Rene Hurlemann, Muhammad Sajid Hussain
    Abstract:

    In our recent clinical trial, increased peripheral concentrations of pro-inflammatory molecular mediators were determined in complex regional pain syndrome (CRPS) patients. After 3 months adjunctive unilateral, selective L4 dorsal root ganglion stimulation (L4-DRGSTIM), significantly decreased serum IL-10 and increased saliva oxytocin levels were assessed along with an improved pain and functional state. The current study extended molecular profiling towards gene expression analysis of genes known to be involved in the gonadotropin releasing Hormone Receptor and neuroinflammatory (cytokines/chemokines) signaling pathways. Blood samples were collected from 12 CRPS patients for whole-transcriptome profiling in order to assay 18,845 inflammation-associated genes from frozen blood at baseline and after 3 months L4-DRGSTIM using PANTHER™ pathway enrichment analysis tool. Pathway enrichment analyses tools (GOrilla™ and PANTHER™) showed predominant involvement of inflammation mediated by chemokines/cytokines and gonadotropin releasing Hormone Receptor pathways. Further, screening of differentially regulated genes showed changes in innate immune response related genes. Transcriptomic analysis showed that 21 genes (predominantly immunoinflammatory) were significantly changed after L4-DRGSTIM. Seven genes including TLR1, FFAR2, IL1RAP, ILRN, C5, PKB and IL18 were down regulated and fourteen genes including CXCL2, CCL11, IL36G, CRP, SCGB1A1, IL-17F, TNFRSF4, PLA2G2A, CREB3L3, ADAMTS12, IL1F10, NOX1, CHIA and BDKRB1 were upregulated. In our sub-group analysis of L4-DRGSTIM treated CRPS patients, we found either upregulated or downregulated genes involved in immunoinflammatory circuits relevant for the pathophysiology of CRPS indicating a possible relation. However, large biobank-based approaches are recommended to establish genetic phenotyping as a quantitative outcome measure in CRPS patients. Trial registration The study protocol was registered at the 15.11.2016 on German Register for Clinical Trials (DRKS ID 00011267). https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011267

Muhammad Sajid Hussain - One of the best experts on this subject based on the ideXlab platform.

  • unilateral l4 dorsal root ganglion stimulation evokes pain relief in chronic neuropathic postsurgical knee pain and changes of inflammatory markers part ii whole transcriptome profiling
    Journal of Translational Medicine, 2019
    Co-Authors: Thomas M Kinfe, M Asif, Krishnan Chakravarthy, Timothy R Deer, Jeffery M Kramer, Thomas L Yearwood, Rene Hurlemann, Muhammad Sajid Hussain
    Abstract:

    In our recent clinical trial, increased peripheral concentrations of pro-inflammatory molecular mediators were determined in complex regional pain syndrome (CRPS) patients. After 3 months adjunctive unilateral, selective L4 dorsal root ganglion stimulation (L4-DRGSTIM), significantly decreased serum IL-10 and increased saliva oxytocin levels were assessed along with an improved pain and functional state. The current study extended molecular profiling towards gene expression analysis of genes known to be involved in the gonadotropin releasing Hormone Receptor and neuroinflammatory (cytokines/chemokines) signaling pathways. Blood samples were collected from 12 CRPS patients for whole-transcriptome profiling in order to assay 18,845 inflammation-associated genes from frozen blood at baseline and after 3 months L4-DRGSTIM using PANTHER™ pathway enrichment analysis tool. Pathway enrichment analyses tools (GOrilla™ and PANTHER™) showed predominant involvement of inflammation mediated by chemokines/cytokines and gonadotropin releasing Hormone Receptor pathways. Further, screening of differentially regulated genes showed changes in innate immune response related genes. Transcriptomic analysis showed that 21 genes (predominantly immunoinflammatory) were significantly changed after L4-DRGSTIM. Seven genes including TLR1, FFAR2, IL1RAP, ILRN, C5, PKB and IL18 were down regulated and fourteen genes including CXCL2, CCL11, IL36G, CRP, SCGB1A1, IL-17F, TNFRSF4, PLA2G2A, CREB3L3, ADAMTS12, IL1F10, NOX1, CHIA and BDKRB1 were upregulated. In our sub-group analysis of L4-DRGSTIM treated CRPS patients, we found either upregulated or downregulated genes involved in immunoinflammatory circuits relevant for the pathophysiology of CRPS indicating a possible relation. However, large biobank-based approaches are recommended to establish genetic phenotyping as a quantitative outcome measure in CRPS patients. Trial registration The study protocol was registered at the 15.11.2016 on German Register for Clinical Trials (DRKS ID 00011267). https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011267

Rene Hurlemann - One of the best experts on this subject based on the ideXlab platform.

  • unilateral l4 dorsal root ganglion stimulation evokes pain relief in chronic neuropathic postsurgical knee pain and changes of inflammatory markers part ii whole transcriptome profiling
    Journal of Translational Medicine, 2019
    Co-Authors: Thomas M Kinfe, M Asif, Krishnan Chakravarthy, Timothy R Deer, Jeffery M Kramer, Thomas L Yearwood, Rene Hurlemann, Muhammad Sajid Hussain
    Abstract:

    In our recent clinical trial, increased peripheral concentrations of pro-inflammatory molecular mediators were determined in complex regional pain syndrome (CRPS) patients. After 3 months adjunctive unilateral, selective L4 dorsal root ganglion stimulation (L4-DRGSTIM), significantly decreased serum IL-10 and increased saliva oxytocin levels were assessed along with an improved pain and functional state. The current study extended molecular profiling towards gene expression analysis of genes known to be involved in the gonadotropin releasing Hormone Receptor and neuroinflammatory (cytokines/chemokines) signaling pathways. Blood samples were collected from 12 CRPS patients for whole-transcriptome profiling in order to assay 18,845 inflammation-associated genes from frozen blood at baseline and after 3 months L4-DRGSTIM using PANTHER™ pathway enrichment analysis tool. Pathway enrichment analyses tools (GOrilla™ and PANTHER™) showed predominant involvement of inflammation mediated by chemokines/cytokines and gonadotropin releasing Hormone Receptor pathways. Further, screening of differentially regulated genes showed changes in innate immune response related genes. Transcriptomic analysis showed that 21 genes (predominantly immunoinflammatory) were significantly changed after L4-DRGSTIM. Seven genes including TLR1, FFAR2, IL1RAP, ILRN, C5, PKB and IL18 were down regulated and fourteen genes including CXCL2, CCL11, IL36G, CRP, SCGB1A1, IL-17F, TNFRSF4, PLA2G2A, CREB3L3, ADAMTS12, IL1F10, NOX1, CHIA and BDKRB1 were upregulated. In our sub-group analysis of L4-DRGSTIM treated CRPS patients, we found either upregulated or downregulated genes involved in immunoinflammatory circuits relevant for the pathophysiology of CRPS indicating a possible relation. However, large biobank-based approaches are recommended to establish genetic phenotyping as a quantitative outcome measure in CRPS patients. Trial registration The study protocol was registered at the 15.11.2016 on German Register for Clinical Trials (DRKS ID 00011267). https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00011267

Robert P Millar - One of the best experts on this subject based on the ideXlab platform.

  • cytoskeletal reorganization dependence of signaling by the gonadotropin releasing Hormone Receptor
    Journal of Biological Chemistry, 2004
    Co-Authors: Lindsay Davidson, Adam J Pawson, Robert P Millar, Stuart Maudsley
    Abstract:

    Activation of classical G protein-coupled Receptors (GPCRs) like the mammalian Gonadotropin-Releasing Hormone Receptor (GnRHR) typically stimulates heterotrimeric G protein molecules that subsequently activate downstream effectors. Receptor activation of heterotrimeric G protein pathways primarily controls intermediary cell metabolism by elevation or diminution of soluble cytoplasmic second messenger molecules. We have demonstrated here that stimulation of the GnRHR also results in a dramatic change in both cell adhesion and superstructural morphology. Gonadotropin-Releasing Hormone (GnRH) Receptor activation rapidly increases the capacity of HEK293 cells expressing the GnRHR to remain matrix-adherent in the face of fluid insults. Coinciding with this profound elevation in matrix adherence, we demonstrated a GnRH-induced alteration in both cell morphology and the de novo generation of polymerized actin structures. GnRH induction of cytoskeletal remodeling was correlated with significant increases in the tyrosine phosphorylation status of a series of cytoskeletal associated proteins, e.g. focal adhesion kinase (FAK), c-Src, and microtubule-associated protein kinase (MAPK or ERK1/2). The activation of the distal downstream effector ERK1/2 was demonstrated to be sensitive to the disrupters of cytoskeletal rearrangement, cytochalasin D and latrunculin B. In addition to the sensitivity of ERKs to cytoskeletal integrity, GnRH-induced FAK and c-Src kinase activation were sensitive to these agents and the fibronectin-integrin antagonistic RGDS peptide. Activation of ERK was dependent on its protein-protein assembly with FAK and c-Src at focal adhesion complexes. Induction of the cell remodeling event leading to this signaling complex assembly occurred primarily via GnRHR activation of the monomeric G protein Rac but not RhoA. These findings demonstrated a clear divergence of GnRHR signaling via the Rac monomeric G protein focal adhesion signaling complex assembly and cytoskeletal remodeling independent of the classical heterotrimeric G protein-controlled phospholipase C-beta pathway.

  • cytoskeletal reorganization dependence of signaling by the gonadotropin releasing Hormone Receptor
    Journal of Biological Chemistry, 2004
    Co-Authors: Lindsay Davidson, Adam J Pawson, Robert P Millar, Stuart Maudsley
    Abstract:

    Abstract Activation of classical G protein-coupled Receptors (GPCRs) like the mammalian Gonadotropin-Releasing Hormone Receptor (GnRHR) typically stimulates heterotrimeric G protein molecules that subsequently activate downstream effectors. Receptor activation of heterotrimeric G protein pathways primarily controls intermediary cell metabolism by elevation or diminution of soluble cytoplasmic second messenger molecules. We have demonstrated here that stimulation of the GnRHR also results in a dramatic change in both cell adhesion and superstructural morphology. Gonadotropin-Releasing Hormone (GnRH) Receptor activation rapidly increases the capacity of HEK293 cells expressing the GnRHR to remain matrix-adherent in the face of fluid insults. Coinciding with this profound elevation in matrix adherence, we demonstrated a GnRH-induced alteration in both cell morphology and the de novo generation of polymerized actin structures. GnRH induction of cytoskeletal remodeling was correlated with significant increases in the tyrosine phosphorylation status of a series of cytoskeletal associated proteins, e.g. focal adhesion kinase (FAK), c-Src, and microtubule-associated protein kinase (MAPK or ERK1/2). The activation of the distal downstream effector ERK1/2 was demonstrated to be sensitive to the disrupters of cytoskeletal rearrangement, cytochalasin D and latrunculin B. In addition to the sensitivity of ERKs to cytoskeletal integrity, GnRH-induced FAK and c-Src kinase activation were sensitive to these agents and the fibronectin-integrin antagonistic RGDS peptide. Activation of ERK was dependent on its protein-protein assembly with FAK and c-Src at focal adhesion complexes. Induction of the cell remodeling event leading to this signaling complex assembly occurred primarily via GnRHR activation of the monomeric G protein Rac but not RhoA. These findings demonstrated a clear divergence of GnRHR signaling via the Rac monomeric G protein focal adhesion signaling complex assembly and cytoskeletal remodeling independent of the classical heterotrimeric G protein-controlled phospholipase C-β pathway.

  • a transcriptionally active human type ii gonadotropin releasing Hormone Receptor gene homolog overlaps two genes in the antisense orientation on chromosome 1q 12
    Endocrinology, 2003
    Co-Authors: Kevin Morgan, Darrell C Conklin, Adam J Pawson, Robin Sellar, Thomas R Ott, Robert P Millar
    Abstract:

    GnRH-II peptide Hormone exhibits complete sequence conservation across vertebrate species, including man. Type-II GnRH Receptor genes have been characterized recently in nonhuman primates, but the human Receptor gene homolog contains a frameshift, a premature stop codon (UGA), and a 3' overlap of the RBM8A gene on chromosome 1q.12. A retrotransposed pseudogene, RBM8B, retains partial Receptor sequence. In this study, bioinformatics show that the human Receptor gene promoter overlaps the peroxisomal protein 11-beta gene promoter and the premature UGA is positionally conserved in chimpanzee. A CGA [arginine (Arg)] occurs in porcine DNA, but UGA is shifted one codon to the 5' direction in bovine DNA, suggesting independent evolution of premature stop codons. In contrast to marmoset tissue RNA, exon- and strand-specific probes are required to distinguish differently spliced human Receptor gene transcripts in cell lines (HP75, IMR-32). RBM8B is not transcribed. Sequencing of cDNAs for spliced Receptor mRNAs showed no evidence for alteration of the premature UGA by RNA editing, but alternative splicing circumvents the frameshift to encode a two-membrane-domain protein before this UGA. A stem-loop motif resembling a selenocysteine insertion sequence and a potential alternative translation initiation site might enable expression of further proteins involved in interactions within the GnRH system.

  • two gonadotropin releasing Hormone Receptor subtypes with distinct ligand selectivity and differential distribution in brain and pituitary in the goldfish carassius auratus
    Proceedings of the National Academy of Sciences of the United States of America, 1999
    Co-Authors: Nicola Illing, Brigitte E Troskie, C S Nahorniak, Janet P Hapgood, Richard E Peter, Robert P Millar
    Abstract:

    In the goldfish (Carassius auratus) the two endogenous forms of Gonadotropin-Releasing Hormone (GnRH), namely chicken GnRH II ([His5,Trp7,Tyr8]GnRH) and salmon GnRH ([Trp7,Leu8]GnRH), stimulate the release of both gonadotropins and growth Hormone from the pituitary. This control is thought to occur by means of the stimulation of distinct GnRH Receptors. These Receptors can be distinguished on the basis of differential gonadotropin and growth Hormone releasing activities of naturally occurring GnRHs and GnRHs with variant amino acids in position 8. We have cloned the cDNAs of two GnRH Receptors, GfA and GfB, from goldfish brain and pituitary. Although the Receptors share 71% identity, there are marked differences in their ligand selectivity. Both Receptors are expressed in the pituitary but are differentially expressed in the brain, ovary, and liver. Thus we have found and cloned two full-length cDNAs that appear to correspond to different forms of GnRH Receptor, with distinct pharmacological characteristics and tissue distribution, in a single species.

  • functional microdomains in g protein coupled Receptors the conserved arginine cage motif in the gonadotropin releasing Hormone Receptor
    Journal of Biological Chemistry, 1998
    Co-Authors: Juan A Ballesteros, Robert P Millar, Karel Konvicka, J S Davidson, Smiljka Kitanovic, Frank Guarnieri, Peter Davies, Bernard J Fromme, Ling Chi, Harel Weinstein
    Abstract:

    Abstract An Arg present in the third transmembrane domain of all rhodopsin-like G-protein-coupled Receptors is required for efficient signal transduction. Mutation of this Arg in the Gonadotropin-Releasing Hormone Receptor to Gln, His, or Lys abolished or severely impaired agonist-stimulated inositol phosphate generation, consistent with Arg having a role in Receptor activation. To investigate the contribution of the surrounding structural domain in the actions of the conserved Arg, an integrated microdomain modeling and mutagenesis approach has been utilized. Two conserved residues that constrain the Arg side chain to a limited number of conformations have been identified. In the inactive wild-type Receptor, the Arg side chain is proposed to form an ionic interaction with Asp3.49(138). Experimental results for the Asp3.49(138) → Asn mutant Receptor show a modestly enhanced Receptor efficiency, consistent with the hypothesis that weakening the Asp3.49(138)-Arg3.50(139)interaction by protonation of the Asp or by the mutation to Asn favors activation. With activation, the Asp3.49(138)-Arg3.50(139) ionic bond would break, and the unrestrained Arg would be prevented from orienting itself toward the water phase by a steric clash with Ile3.54(143). The mutation Ile3.54(143) → Ala, which eliminates this clash in simulations, causes a marked reduction in measured Receptor signaling efficiency, implying that solvation of Arg3.50(139) prevents it from functioning in the activation of the Receptor. These data are consistent with residues Asp3.49(138) and Ile3.54(143) forming a structural motif, which helps position Arg in its appropriate inactive and active Receptor conformations.

Stuart C Sealfon - One of the best experts on this subject based on the ideXlab platform.

  • gonadotropin releasing Hormone Receptor coupled gene network organization
    Journal of Biological Chemistry, 2001
    Co-Authors: Elisa Wurmbach, Tony Yuen, Barbara J Ebersole, Stuart C Sealfon
    Abstract:

    Abstract An early gene cDNA microarray was developed to study genes that are regulated immediately following Gonadotropin-Releasing Hormone (GnRH) Receptor activation. 956 selected candidate genes were printed in triplicate, a tstatistic-based regulation algorithm was used for data analysis, and the response to GnRH in a time course from 1 to 6 h was determined. Measurements were highly reproducible within arrays, between arrays, and between experiments. Accuracy and algorithm reliability were established by real-time polymerase chain reaction assays of 60 genes. Gene changes ranging from 1.3- to 31-fold on the microarray were confirmed by real-time polymerase chain reaction. Many of the genes were found to be highly regulated. The regulated genes identified were all elevated at 1 h of treatment and returned nearly or completely to baseline levels of expression by 3 h of treatment. This broad, robust, and transient transcriptional response to constant GnRH exposure includes modulators of signal transduction (e.g. Rgs2 and IκB), cytoskeletal proteins (e.g. γ-actin), and transcription factors (e.g. c-Fos, Egr1, and LRG21). The interplay of the activators, repressors, and feedback inhibitors identified embodies a combinatorial code to direct the activity of specific downstream secondary genes.

  • rhodopsin family Receptors associate with small g proteins to activate phospholipase d
    Nature, 1998
    Co-Authors: Rory Mitchell, Derek A Mcculloch, Eve M Lutz, Melanie S Johnson, Chris Mackenzie, Myles Fennell, G Fink, Wei Zhou, Stuart C Sealfon
    Abstract:

    G-protein-coupled Receptors of the rhodopsin family transduce many important neural and endocrine signals. These Receptors activate heterotrimeric G proteins and in many cases also cause activation of phospholipase D, an enzyme that can be controlled by the small G proteins ARF and RhoA1,2,3. Here we show that the activation of phospholipase D that is induced by many, but not all, Ca2+-mobilizing G-protein-coupled Receptors is sensitive to inhibitors of ARF and of RhoA. Receptors of this type were co-immunoprecipitated with ARF or RhoA on exposure to agonists, and the effects of GTP analogues on ligand binding to the Receptor changed to a profile that is characteristic of small G proteins. These Receptors contain the amino-acid sequence AsnProXXTyr in their seventh transmembrane domain, whereas Receptors capable of activating phospholipase D without involving ARF contain the sequence AspProXXTyr. Mutation of this latter sequence to AsnProXXTyr in the Gonadotropin-Releasing Hormone Receptor conferred sensitivity to an inhibitor of ARF, and the reciprocal mutation in the 5-HT2A Receptor for 5-hydroxytryptamine reduced its sensitivity to the inhibitor. Receptors carrying the AsnProXXTyr motif thus seem to form functional complexes with ARF and RhoA.

  • molecular mechanisms of ligand interaction with the gonadotropin releasing Hormone Receptor
    Endocrine Reviews, 1997
    Co-Authors: Stuart C Sealfon, Harel Weinstein, Robert P Millar
    Abstract:

    I. Introduction II. Amino Acid Sequences of GnRH Receptors A. GnRH Receptor cDNAs B. General structural features C. Covalent modifications D. Gene structure III. Structure-Activity Relations of GnRH Peptides A. Overview B. Comparative structures and activities of vertebrate GnRHs C. Roles of individual amino acids in GnRH activity at the mammalian Receptor D. Conclusions from peptide structure-activity data IV. Structure and Conformation of GnRH and Its Analogs A. Early studies of GnRH conformation B. Integrated computational and experimental studies C. Exploration of the entire conformation space of GnRH analogs V. Functional Structure of the Receptor and Ligand-Receptor Complex A. Extracellular domains B. Helix domains C. Intracellular loop domains D. Computational modeling of three-dimensional Receptor structure VI. Conclusions

  • a locus of the gonadotropin releasing Hormone Receptor that differentiates agonist and antagonist binding sites
    Journal of Biological Chemistry, 1995
    Co-Authors: Wei Zhou, Robert P Millar, Colleen A Flanagan, Harel Weinstein, Smiljka Kitanovic, Ling Chi, Vladimir Rodic, Saul Maayani, Stuart C Sealfon
    Abstract:

    Abstract The decapeptide Gonadotropin-Releasing Hormone controls reproductive function via interaction with a heptahelical G protein-coupled Receptor. Because a molecular model of the Receptor predicts that Lys in the third transmembrane helix contributes to the binding pocket, the function of this side chain was studied by site-directed mutagenesis. Substitution of Arg at this position preserved high affinity agonist binding, whereas Gln at this position reduced binding below the limits of detection. Leu and Asp at this locus abolished both binding and detectable signal transduction. The EC of concentration-response curves for coupling to phosphatidyl inositol hydrolysis obtained with the Gln Receptor was more than 3 orders of magnitude higher than that obtained for the wild-type Receptor. In order to determine whether the increased EC obtained with this mutant reflects an altered Receptor affinity, the effect of decreases in wild-type Receptor density on concentration-response curves was determined by irreversible antagonism. Progressively decreasing the concentration of the wild-type Receptor increased the EC values obtained to a maximal level of 2.4 ± 0.2 nM. Comparison of this value with the EC of 282 ± 52 nM observed with the Gln Receptor mutant indicates that the agonist affinity for this mutant is reduced more than 100-fold. In contrast, antagonist had comparable high affinities for the wild-type, Arg, and Gln mutants. The results indicate that a charge-strengthened hydrogen bond donor is required at this locus for high affinity agonist binding but not for high affinity antagonist binding.

  • glutamate 301 of the mouse gonadotropin releasing Hormone Receptor confers specificity for arginine 8 of mammalian gonadotropin releasing Hormone
    Journal of Biological Chemistry, 1994
    Co-Authors: Colleen A Flanagan, Wei Zhou, Stuart C Sealfon, J S Davidson, Inga I Becker, I Wakefield, Robert P Millar
    Abstract:

    Abstract The Arg residue at position 8 of mammalian GnRH is necessary for high affinity binding to mammalian GnRH Receptors. This requirement has been postulated to derive from an electrostatic interaction of Arg8 with a negatively charged Receptor residue. In order to identify such a residue, 8 conserved acidic residues of the mouse GnRH Receptor were mutated to isosteric Asn or Gln. Mutant Receptors were tested for decreased preference for Arg8-containing ligands by ligand binding and inositol phosphate production. One of the mutants, in which the Glu301 residue was mutated to Gln, exhibited a 56-fold decrease in apparent affinity for mammalian GnRH. The mutant Receptor also exhibited decreased affinity for [Lys8]GnRH, but its affinity for [Gln8]GnRH was unchanged compared with the wild type Receptor. The apparent affinity of the mutant Receptor for the acidic analogue, [Glu8]GnRH, was increased more than 10-fold. The mutant Receptor did not, therefore, distinguish mammalian GnRH from analogues with amino acid substitutions at position 8 as effectively as the wild type Receptor. This loss of discrimination was specific for the residue at position 8, because the mutant Receptor did distinguish mammalian GnRH from analogues with favorable substitutions at positions 5, 6, and 7. These findings show that Glu301 of the GnRH Receptor plays a role in Receptor recognition of Arg8 in the ligand and are consistent with an electrostatic interaction between these 2 residues.