The Experts below are selected from a list of 3732 Experts worldwide ranked by ideXlab platform
Morley D. Hollenberg - One of the best experts on this subject based on the ideXlab platform.
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Proteinase Activated Receptor 2 par2 decreases apoptosis in colonic epithelial cells
Journal of Biological Chemistry, 2014Co-Authors: Vadim Iablokov, Morley D. Hollenberg, Rithwik Ramachandran, Christina Hirota, Michael A Peplowski, Koichiro Mihara, Wallace K. MacnaughtonAbstract:Mucosal biopsies from inflamed colon of inflammatory bowel disease patients exhibit elevated epithelial apoptosis compared with those from healthy individuals, disrupting mucosal homeostasis and perpetuating disease. Therapies that decrease intestinal epithelial apoptosis may, therefore, ameliorate inflammatory bowel disease, but treatments that specifically target apoptotic pathways are lacking. Proteinase-Activated Receptor-2 (PAR2), a G protein-coupled Receptor Activated by trypsin-like serine Proteinases, is expressed on intestinal epithelial cells and stimulates mitogenic pathways upon activation. We sought to determine whether PAR2 activation and signaling could rescue colonic epithelial (HT-29) cells from apoptosis induced by proapoptotic cytokines that are increased during inflammatory bowel disease. The PAR2 agonists 2-furoyl-LIGRLO (2f-LI), SLIGKV and trypsin all significantly reduced cleavage of caspase-3, -8, and -9, poly(ADP-ribose) polymerase, and the externalization of phosphatidylserine after treatment of cells with IFN-γ and TNF-α. Knockdown of PAR2 with siRNA eliminated the anti-apoptotic effect of 2f-LI and increased the sensitivity of HT-29 cells to cytokine-induced apoptosis. Concurrent inhibition of both MEK1/2 and PI3K was necessary to inhibit PAR2-induced survival. 2f-LI was found to increase phosphorylation and inactivation of pro-apoptotic BAD at Ser(112) and Ser(136) by MEK1/2 and PI3K-dependent signaling, respectively. PAR2 activation also increased the expression of anti-apoptotic MCL-1. Simultaneous knockdown of both BAD and MCL-1 had minimal effects on PAR2-induced survival, whereas single knockdown had no effect. We conclude that PAR2 activation reduces cytokine-induced epithelial apoptosis via concurrent stimulation of MEK1/2 and PI3K but little involvement of MCL-1 and BAD. Our findings represent a novel mechanism whereby serine Proteinases facilitate epithelial cell survival and may be important in the context of colonic healing.
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Epidermal growth factor Receptor transactivation is required for Proteinase-Activated Receptor-2-induced COX-2 expression in intestinal epithelial cells.
American journal of physiology. Gastrointestinal and liver physiology, 2012Co-Authors: Christina Hirota, Morley D. Hollenberg, Vadim Iablokov, Michael Dicay, Bernard Renaux, Wallace K. MacnaughtonAbstract:Proteinase-Activated Receptor (PAR)2, a G protein-coupled Receptor Activated by serine Proteinases, has been implicated in both intestinal inflammation and epithelial proliferation. Cyclooxygenase ...
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Proteinase Activated Receptor 1 mediates dorsal root ganglion neuronal degeneration in hiv aids
Brain, 2011Co-Authors: Shaona Acharjee, Morley D. Hollenberg, Yu Zhu, Ferdinand Maingat, Carlos A. Pardo, Klaus Ballanyi, Christopher PowerAbstract:Distal sensory polyneuropathy is a frequent complication of lentivirus infections of the peripheral nervous system including both human immunodeficiency virus and feline immunodeficiency virus. Proteinase-Activated Receptors are G protein-coupled Receptors implicated in the pathogenesis of neuroinflammation and neurodegeneration. Proteinase-Activated Receptor-1 is expressed on different cell types within the nervous system including neurons and glia, but little is known about its role in the pathogenesis of inflammatory peripheral nerve diseases, particularly lentivirus-related distal sensory polyneuropathy. Herein, the expression and functions of Proteinase-Activated Receptor-1 in the peripheral nervous system during human immunodeficiency virus and feline immunodeficiency virus infections were investigated. Proteinase-Activated Receptor-1 expression was most evident in autopsied dorsal root ganglion neurons from subjects infected with human immunodeficiency virus, compared with the dorsal root ganglia of uninfected subjects. Human immunodeficiency virus or feline immunodeficiency virus infection of cultured human or feline dorsal root ganglia caused upregulation of interleukin-1β and Proteinase-Activated Receptor-1 expression. In the human immunodeficiency virus- or feline immunodeficiency virus-infected dorsal root ganglia, interleukin-1β activation was principally detected in macrophages, while neurons showed induction of Proteinase-Activated Receptor-1. Binding of Proteinase-Activated Receptor-1 by the selective Proteinase-Activated Receptor-1-activating peptide resulted in neurite retraction and soma atrophy in conjunction with cytosolic calcium activation in human dorsal root ganglion neurons. Interleukin-1β exposure to feline or human dorsal root ganglia caused upregulation of Proteinase-Activated Receptor-1 in neurons. Exposure of feline immunodeficiency virus-infected dorsal root ganglia to the interleukin-1 Receptor antagonist prevented Proteinase-Activated Receptor-1 induction and neurite retraction. In vivo feline immunodeficiency virus infection was associated with increased Proteinase-Activated Receptor-1 expression on neurons and interleukin-1β induction in macrophages. Moreover, feline immunodeficiency virus infection caused hyposensitivity to mechanical stimulation. These data indicated that activation and upregulation of Proteinase-Activated Receptor-1 by interleukin-1β contributed to dorsal root ganglion neuronal damage during lentivirus infections leading to the development of distal sensory polyneuropathy and might also provide new targets for future therapeutic interventions. * Abbreviations : FIV : feline immunodeficiency virus HIV : human immunodeficiency virus PAR : Proteinase-Activated Receptor
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Proteinase-Activated Receptor-1 mediates dorsal root ganglion neuronal degeneration in HIV/AIDS
Brain, 2011Co-Authors: Shaona Acharjee, Morley D. Hollenberg, Yu Zhu, Ferdinand Maingat, Carlos A. Pardo, Klaus Ballanyi, Christopher PowerAbstract:Distal sensory polyneuropathy is a frequent complication of lentivirus infections of the peripheral nervous system including both human immunodeficiency virus and feline immunodeficiency virus. Proteinase-Activated Receptors are G protein-coupled Receptors implicated in the pathogenesis of neuroinflammation and neurodegeneration. Proteinase-Activated Receptor-1 is expressed on different cell types within the nervous system including neurons and glia, but little is known about its role in the pathogenesis of inflammatory peripheral nerve diseases, particularly lentivirus-related distal sensory polyneuropathy. Herein, the expression and functions of Proteinase-Activated Receptor-1 in the peripheral nervous system during human immunodeficiency virus and feline immunodeficiency virus infections were investigated. Proteinase-Activated Receptor-1 expression was most evident in autopsied dorsal root ganglion neurons from subjects infected with human immunodeficiency virus, compared with the dorsal root ganglia of uninfected subjects. Human immunodeficiency virus or feline immunodeficiency virus infection of cultured human or feline dorsal root ganglia caused upregulation of interleukin-1β and Proteinase-Activated Receptor-1 expression. In the human immunodeficiency virus- or feline immunodeficiency virus-infected dorsal root ganglia, interleukin-1β activation was principally detected in macrophages, while neurons showed induction of Proteinase-Activated Receptor-1. Binding of Proteinase-Activated Receptor-1 by the selective Proteinase-Activated Receptor-1-activating peptide resulted in neurite retraction and soma atrophy in conjunction with cytosolic calcium activation in human dorsal root ganglion neurons. Interleukin-1β exposure to feline or human dorsal root ganglia caused upregulation of Proteinase-Activated Receptor-1 in neurons. Exposure of feline immunodeficiency virus-infected dorsal root ganglia to the interleukin-1 Receptor antagonist prevented Proteinase-Activated Receptor-1 induction and neurite retraction. In vivo feline immunodeficiency virus infection was associated with increased Proteinase-Activated Receptor-1 expression on neurons and interleukin-1β induction in macrophages. Moreover, feline immunodeficiency virus infection caused hyposensitivity to mechanical stimulation. These data indicated that activation and upregulation of Proteinase-Activated Receptor-1 by interleukin-1β contributed to dorsal root ganglion neuronal damage during lentivirus infections leading to the development of distal sensory polyneuropathy and might also provide new targets for future therapeutic interventions. * Abbreviations : FIV : feline immunodeficiency virus HIV : human immunodeficiency virus PAR : Proteinase-Activated Receptor
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Proteinase-Activated Receptor-1 mediates dorsal root ganglion neuronal degeneration in HIV/AIDS.
Brain : a journal of neurology, 2011Co-Authors: Shaona Acharjee, Morley D. Hollenberg, Yu Zhu, Ferdinand Maingat, Klaus Ballanyi, Carlos Pardo, Christopher PowerAbstract:Distal sensory polyneuropathy is a frequent complication of lentivirus infections of the peripheral nervous system including both human immunodeficiency virus and feline immunodeficiency virus. Proteinase-Activated Receptors are G protein-coupled Receptors implicated in the pathogenesis of neuroinflammation and neurodegeneration. Proteinase-Activated Receptor-1 is expressed on different cell types within the nervous system including neurons and glia, but little is known about its role in the pathogenesis of inflammatory peripheral nerve diseases, particularly lentivirus-related distal sensory polyneuropathy. Herein, the expression and functions of Proteinase-Activated Receptor-1 in the peripheral nervous system during human immunodeficiency virus and feline immunodeficiency virus infections were investigated. Proteinase-Activated Receptor-1 expression was most evident in autopsied dorsal root ganglion neurons from subjects infected with human immunodeficiency virus, compared with the dorsal root ganglia of uninfected subjects. Human immunodeficiency virus or feline immunodeficiency virus infection of cultured human or feline dorsal root ganglia caused upregulation of interleukin-1β and Proteinase-Activated Receptor-1 expression. In the human immunodeficiency virus- or feline immunodeficiency virus-infected dorsal root ganglia, interleukin-1β activation was principally detected in macrophages, while neurons showed induction of Proteinase-Activated Receptor-1. Binding of Proteinase-Activated Receptor-1 by the selective Proteinase-Activated Receptor-1-activating peptide resulted in neurite retraction and soma atrophy in conjunction with cytosolic calcium activation in human dorsal root ganglion neurons. Interleukin-1β exposure to feline or human dorsal root ganglia caused upregulation of Proteinase-Activated Receptor-1 in neurons. Exposure of feline immunodeficiency virus-infected dorsal root ganglia to the interleukin-1 Receptor antagonist prevented Proteinase-Activated Receptor-1 induction and neurite retraction. In vivo feline immunodeficiency virus infection was associated with increased Proteinase-Activated Receptor-1 expression on neurons and interleukin-1β induction in macrophages. Moreover, feline immunodeficiency virus infection caused hyposensitivity to mechanical stimulation. These data indicated that activation and upregulation of Proteinase-Activated Receptor-1 by interleukin-1β contributed to dorsal root ganglion neuronal damage during lentivirus infections leading to the development of distal sensory polyneuropathy and might also provide new targets for future therapeutic interventions.
Nathalie Vergnolle - One of the best experts on this subject based on the ideXlab platform.
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functional characterization and expression analysis of the Proteinase Activated Receptor 2 in human cutaneous mast cells
Journal of Investigative Dermatology, 2006Co-Authors: Corinna Moormann, Nathalie Vergnolle, Jörg Buddenkotte, Metin Artuc, Elena E Pohl, Georg Varga, Randolf Brehler, Beate M Henz, Stefan W Schneider, Thomas A. LugerAbstract:Proteinase-Activated Receptor-2 (PAR2) belongs to a new G protein-coupled Receptor subfamily Activated by serine Proteinases. PAR2 has been demonstrated to play a role during inflammation and immune response in different tissues including the skin. We examined whether PAR2 is functionally expressed by cutaneous human primary skin mast cells (HPMC) and the human mast cell line 1 (HMC-1). Reverse transcription-polymerase chain reaction and FACS analysis show expression of PAR2 both at the RNA and protein level. HPMCs and HMC-1 also express PAR1, PAR3, and PAR4. Ca-mobilization studies demonstrate functional PAR2 expressed by human skin mast cells, as shown by natural and synthetic PAR2 agonists. PAR2 agonists induced histamine release from HPMC indicating a role of PAR2 in regulating inflammatory and immune responses by skin mast cells. Double-immunofluorescence staining reveals colocalization of PAR2 with tryptase in the majority of human skin mast cells. In conclusion, trypsin and tryptase as well as specific agonists for PAR2 were able to induce Ca2+ mobilization in HPMCs, and agonists of PAR2 induce the release of histamine from these cells. Thus, PAR2 may be an important regulator of skin mast cell function during cutaneous inflammation and hypersensitivity.
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a major role for proteolytic activity and Proteinase Activated Receptor 2 in the pathogenesis of infectious colitis
Proceedings of the National Academy of Sciences of the United States of America, 2005Co-Authors: Kristina K Hansen, Morley D. Hollenberg, John L. Wallace, Laurie Cellars, Patricia Andradegordon, Philip M Sherman, Zhengying Pan, Amos Baruch, Nathalie VergnolleAbstract:Citrobacter rodentium is a bacterial pathogen that causes a murine infectious colitis equivalent to enterohemorrhagic Escherichia coli infection in humans. Colonic luminal fluid from C. rodentium-infected mice, but not from sham-infected mice, contains active serine Proteinases that can activate Proteinase-Activated Receptor-2 (PAR2). We have identified granzyme A and murine trypsins to be present in C. rodentium-infected luminal fluid, as determined by mass spectrometry and Western blot analysis. Inflammatory indices (colonic mucosa macroscopic damage score, increased intestinal wall thickness, granulocyte infiltration, and bacterial translocation from the colonic lumen to peritoneal organs) were all increased in C. rodentium-infected mice, compared with sham-infected mice. Soybean trypsin inhibitor-treated wild-type mice and untreated PAR2-deficient (PAR2-/-) mice (compared with their wild-type littermates) both had substantially reduced levels of C. rodentium-induced inflammation. These data point to an important role for both pathogen-induced host serine Proteinases and PAR2 in the setting of infectious colitis.
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a role for Proteinase Activated Receptor 1 in inflammatory bowel diseases
Journal of Clinical Investigation, 2004Co-Authors: Nathalie Vergnolle, Martin Steinhoff, Nigel W. Bunnett, Laurie Cellars, Andrea Mencarelli, Giovanni Rizzo, Sunita Swaminathan, Paul L Beck, Patricia Andradegordon, Morley D. HollenbergAbstract:Proteinase-Activated Receptor-1 (PAR1), a G protein-coupled Receptor Activated by thrombin, is highly expressed in different cell types of the gastrointestinal tract. The activity of thrombin and of other Proteinases is significantly increased in the colon of inflammatory bowel disease (IBD) patients. Since PAR1 activation in tissues other than the gut provoked inflammation, we hypothesized that PAR1 activation in the colon is involved in the pathogenesis of IBD. Here, we demonstrate that PAR1 is overexpressed in the colon of IBD patients. In mice, intracolonic administration of PAR1 agonists led to an inflammatory reaction characterized by edema and granulocyte infiltration. This PAR1 activation-induced inflammation was dependent on B and T lymphocytes. Moreover, PAR1 activation exacerbated and prolonged inflammation in a mouse model of IBD induced by the intracolonic administration of trinitrobenzene sulfonic acid (TNBS), while PAR1 antagonism significantly decreased the mortality and severity of colonic inflammation induced by TNBS and dextran sodium sulfate. In these 2 models, colitis development was strongly attenuated by PAR1 deficiency. Taken together, these results imply an important role for PAR1 in the pathogenesis of experimental colitis, supporting the notion that PAR1 inhibition may be beneficial in the context of IBD and possibly in other chronic intestinal inflammatory disorders.
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proinflammatory role of Proteinase Activated Receptor 2 in humans and mice during cutaneous inflammation in vivo
The FASEB Journal, 2003Co-Authors: Stephan Seeliger, Nathalie Vergnolle, Jörg Buddenkotte, Nigel W. Bunnett, Martin Schmelz, Claudia K Derian, Roman Nawroth, Pierre Yves Von Der Weid, Cord Sunderkotter, Dieter MetzeAbstract:Proteinase-Activated Receptor-2 belongs to a new subfamily of G-protein-coupled Receptors. Its precise role during inflammation and the underlying mechanisms is still unclear. Our study establishes that PAR-2 plays a direct proinflammatory role during cutaneous inflammation in mice and humans in vivo. In a model of experimentally induced allergic (ACD) and toxic (ICD) contact dermatitis (CD) we show that ear swelling responses, plasma extravasation, and leucocyte adherence were significantly attenuated in PAR-2 null mutant (PAR-2−/−) mice compared with wild-type (PAR-2+/+) mice, especially at early stages. The proinflammatory effects by PAR-2 activation were significantly diminished using nitric oxide-synthase inhibitors, while NF-kappaB and neuropeptides appear to play a minor role in these mechanisms. PAR-2-mediated up-regulation of E-selectin and cell adhesion molecule ICAM-1; enhanced plasma extravasation was observed in humans and mice and of interleukin-6 in mice in vivo. Thus, PAR-2 may be a benefi...
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Proteinase Activated Receptor 1 activation induces epithelial apoptosis and increases intestinal permeability
Proceedings of the National Academy of Sciences of the United States of America, 2003Co-Authors: Alex Chin, Morley D. Hollenberg, Nathalie Vergnolle, John L. Wallace, Wallace K. Macnaughton, Andre G BuretAbstract:Proteinase-Activated Receptor 1 (PAR1)-mediated inflammation remains poorly understood. Here we characterize previously unrecognized effects of PAR1-induced apoptosis signaling, which contributes to epithelial barrier dysfunction. Incubation of epithelial cells with PAR1 agonists induced apoptosis and increased epithelial permeability in a caspase-3-dependent manner. Similarly, studies in vivo demonstrated that intracolonic infusion with PAR1 agonists increased colonic permeability in mice, and that this effect was abolished by pretreatment with a caspase-3 inhibitor. PAR1 agonists induced tight junctional zonula-occludens 1 disruption and apoptotic nuclear condensation. Investigation into signaling pathways showed that these effects were dependent on caspase-3, tyrosine kinase, and myosin light chain kinase. Conversely, the Src kinase inhibitor PP1 augmented zonula-occludens 1 injury and nuclear condensation induced by PAR1 agonists. These results support a role for Proteinases and PARs in intestinal disease and provide new directions for possible therapeutic applications of PAR1 antagonists.
Pankaj J Pasricha - One of the best experts on this subject based on the ideXlab platform.
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Trypsin mediates nociception via the Proteinase-Activated Receptor 2: A potentially novel role in pancreatic pain
Gastroenterology, 2004Co-Authors: Willemijntje A Hoogerwerf, John H Winston, Mohan Shenoy, Shu-yuan Xiao, Pankaj J PasrichaAbstract:Background & Aims: The pathogenesis of pain in pancreatitis remains poorly understood. We hypothesized that trypsin, a key inflammatory mediator in this condition, can also activate nociceptive neurons via the Proteinase-Activated Receptor 2. Methods: Double immunohistochemical staining of T8 to T12 dorsal root ganglia sections was performed with antibodies against Proteinase-Activated Receptor 2 and vanilloid Receptor 1, a marker for primary nociceptive neurons. In vivo nociceptive activity was measured by FOS immunoreactivity in thoracic spinal dorsal horn segments after intrapancreatic administration of Proteinase-Activated Receptor 2 agonists. Pain behavior was assessed by visceromotor reflex activity in response to noxious stimulation of the pancreas with Proteinase-Activated Receptor 2 agonists. Results: Proteinase-Activated Receptor 2 was expressed by virtually all nociceptive neurons in thoracic dorsal root ganglia. Intraductal trypsin, in subinflammatory concentrations, Activated spinal dorsal horn neurons in a dose-dependent manner, as measured by FOS expression. Both trypsin and a Proteinase-Activated Receptor 2–specific peptide agonist induced a behavioral pain response when infused into the pancreatic duct of awake rats. Preinfusion of the pancreatic duct with Proteinase-Activated Receptor 2–specific activating peptide desensitized the response to trypsin. Conclusions: Our findings suggest a novel Proteinase-Activated Receptor 2–mediated role for trypsin in the pathogenesis of pancreatic pain and one that is independent of its inflammatory effect.
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Molecular cloning of the rat Proteinase-Activated Receptor 4 (PAR4)
BMC Molecular Biology, 2002Co-Authors: Willemijntje A Hoogerwerf, Helen Lee Hellmich, Maria Adelaide Micci, John H Winston, Lei Zou, Pankaj J PasrichaAbstract:Background The Proteinase-Activated Receptor 4 (PAR4) is a G-protein-coupled Receptor Activated by proteases such as thrombin and trypsin. Although activation of PAR4 has been shown to modulate rat gastrointestinal motility, the rat PAR4 sequence was unknown until now. This study aimed to identify the rat PAR4 cDNA. Results The cDNA coding for the rat PAR4 homologue was cloned from the duodenum. Northern blots demonstrated a 3.0 kb transcript in the duodenum. Protein homology with mouse and human counterparts was 90% and 75% respectively. PAR4 is expressed predominantly in the esophagus, stomach, duodenum and the spleen. When expressed in COS cells, PAR4 is Activated by trypsin (1 nM), thrombin (50 nM), mouse PAR4 specific peptide (500 μM) and a putative rat PAR4 specific activating peptide (100 μM), as measured by intracellular Ca^2+-changes. Conclusions We have identified and characterized cDNA encoding the rat PAR4 homologue. PAR4 is expressed predominantly in the upper gastrointestinal tract. It is Activated by trypsin, thrombin and its newly identified rat PAR4 specific activating peptide.
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Molecular cloning of the rat Proteinase-Activated Receptor 4 (PAR4)
BMC molecular biology, 2002Co-Authors: Willemijntje A Hoogerwerf, Helen Lee Hellmich, Maria Adelaide Micci, John H Winston, Lei Zou, Pankaj J PasrichaAbstract:Background The Proteinase-Activated Receptor 4 (PAR4) is a G-protein-coupled Receptor Activated by proteases such as thrombin and trypsin. Although activation of PAR4 has been shown to modulate rat gastrointestinal motility, the rat PAR4 sequence was unknown until now. This study aimed to identify the rat PAR4 cDNA.
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The Proteinase-Activated Receptor 2 Is Involved in Nociception
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2001Co-Authors: Willemijntje A Hoogerwerf, Maria Adelaide Micci, John H Winston, Lei Zou, Mohan Shenoy, D. Sun, H. Lee-hellmich, Shu-yuan Xiao, Pankaj J PasrichaAbstract:The Proteinase-Activated Receptor 2 is expressed on a subset of primary afferent neurons and may participate in the neurogenic component of inflammation. We hypothesized that this Receptor may also play a role in neuronal sensitization and contribute to the pathogenesis of pain in inflammatory conditions such as pancreatitis. Using a specific Proteinase-Activated Receptor 2 activating peptide, we found evidence of such sensitization in vitro in the form of enhanced capsaicin- and KCl-evoked release of calcitonin gene-related peptide, a marker for nociceptive signaling. We then demonstrated that injection of the Proteinase-Activated Receptor 2 activating peptide into the pancreatic duct can activate and sensitize pancreas-specific afferent neurons in vivo, as measured by Fos expression in the dorsal horn of the spinal cord. These observations suggest that Proteinase-Activated Receptor 2 contributes to nociceptive signaling and may provide a novel link between inflammation and pain.
Wallace K. Macnaughton - One of the best experts on this subject based on the ideXlab platform.
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Proteinase Activated Receptor 2 par2 decreases apoptosis in colonic epithelial cells
Journal of Biological Chemistry, 2014Co-Authors: Vadim Iablokov, Morley D. Hollenberg, Rithwik Ramachandran, Christina Hirota, Michael A Peplowski, Koichiro Mihara, Wallace K. MacnaughtonAbstract:Mucosal biopsies from inflamed colon of inflammatory bowel disease patients exhibit elevated epithelial apoptosis compared with those from healthy individuals, disrupting mucosal homeostasis and perpetuating disease. Therapies that decrease intestinal epithelial apoptosis may, therefore, ameliorate inflammatory bowel disease, but treatments that specifically target apoptotic pathways are lacking. Proteinase-Activated Receptor-2 (PAR2), a G protein-coupled Receptor Activated by trypsin-like serine Proteinases, is expressed on intestinal epithelial cells and stimulates mitogenic pathways upon activation. We sought to determine whether PAR2 activation and signaling could rescue colonic epithelial (HT-29) cells from apoptosis induced by proapoptotic cytokines that are increased during inflammatory bowel disease. The PAR2 agonists 2-furoyl-LIGRLO (2f-LI), SLIGKV and trypsin all significantly reduced cleavage of caspase-3, -8, and -9, poly(ADP-ribose) polymerase, and the externalization of phosphatidylserine after treatment of cells with IFN-γ and TNF-α. Knockdown of PAR2 with siRNA eliminated the anti-apoptotic effect of 2f-LI and increased the sensitivity of HT-29 cells to cytokine-induced apoptosis. Concurrent inhibition of both MEK1/2 and PI3K was necessary to inhibit PAR2-induced survival. 2f-LI was found to increase phosphorylation and inactivation of pro-apoptotic BAD at Ser(112) and Ser(136) by MEK1/2 and PI3K-dependent signaling, respectively. PAR2 activation also increased the expression of anti-apoptotic MCL-1. Simultaneous knockdown of both BAD and MCL-1 had minimal effects on PAR2-induced survival, whereas single knockdown had no effect. We conclude that PAR2 activation reduces cytokine-induced epithelial apoptosis via concurrent stimulation of MEK1/2 and PI3K but little involvement of MCL-1 and BAD. Our findings represent a novel mechanism whereby serine Proteinases facilitate epithelial cell survival and may be important in the context of colonic healing.
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Epidermal growth factor Receptor transactivation is required for Proteinase-Activated Receptor-2-induced COX-2 expression in intestinal epithelial cells.
American journal of physiology. Gastrointestinal and liver physiology, 2012Co-Authors: Christina Hirota, Morley D. Hollenberg, Vadim Iablokov, Michael Dicay, Bernard Renaux, Wallace K. MacnaughtonAbstract:Proteinase-Activated Receptor (PAR)2, a G protein-coupled Receptor Activated by serine Proteinases, has been implicated in both intestinal inflammation and epithelial proliferation. Cyclooxygenase ...
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EGF Receptor transactivation and MAP kinase mediate Proteinase-Activated Receptor-2-induced chloride secretion in intestinal epithelial cells
American journal of physiology. Gastrointestinal and liver physiology, 2007Co-Authors: Jacques Q. Van Der Merwe, Morley D. Hollenberg, Wallace K. MacnaughtonAbstract:We examined the stimulus-secretion pathways whereby Proteinase-Activated Receptor 2 (PAR-2) stimulates Cl− secretion in intestinal epithelial cells. SCBN and T84 epithelial monolayers grown on Snap...
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Proteinase-Activated Receptor-2 activating peptides: distinct canine coronary artery Receptor systems
American journal of physiology. Heart and circulatory physiology, 2007Co-Authors: Mahmoud Saifeddine, Steeve Houle, Michelle L. Seymour, Yu Pei Xiao, Steven J. Compton, Rithwik Ramachandran, Wallace K. Macnaughton, Serge Simonet, Christine Vayssettes-courchay, Tony VerbeurenAbstract:In canine coronary artery preparations, the Proteinase-Activated Receptor-2 (PAR2) activating peptides (PAR2-APs) SLIGRL-NH2 and 2-furoyl-LIGRLO-NH2 caused both an endothelium-dependent relaxation ...
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Expression of Proteinase-Activated Receptor 2 on human primary gastrointestinal myofibroblasts and stimulation of prostaglandin synthesis.
Canadian journal of physiology and pharmacology, 2005Co-Authors: Michelle L. Seymour, Morley D. Hollenberg, Steven J. Compton, David G Binion, Wallace K. MacnaughtonAbstract:It is known that subepithelial myofibroblast-derived prostaglandin (PG)E2 can regulate intestinal epithelial cell functions, and that Proteinase-Activated Receptor-2 (PAR2) is abundantly expressed ...
Martin Steinhoff - One of the best experts on this subject based on the ideXlab platform.
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role of matriptase and Proteinase Activated Receptor 2 in nonmelanoma skin cancer
Journal of Investigative Dermatology, 2009Co-Authors: Georgeta Bocheva, Martin Steinhoff, Cordula Kempkes, Anke Rattenholl, Tobias Goerge, Chenyong Lin, Michael R Dandrea, Sonja StanderAbstract:Matriptase (membrane-type serine Proteinase) was reported to play a role in nonmelanoma skin cancer progression. Moreover, it was shown to stimulate Proteinase-Activated Receptor-2 (PAR 2 ) in vitro . Hepatocyte growth factor activator inhibitor-1 (HAI-1), the matriptase inhibitor, is an important regulator of enzyme activity. Therefore, the aim of this study was to elucidate the putative role of matriptase, HAI-1, and PAR 2 in normal human skin, as well as in basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs). In normal human epidermis, PAR 2 colocalized with matriptase and HAI-1. Immunoreactivity of all proteins was found to be diminished in BCCs. Likewise, PAR 2 immunoreactivity was significantly decreased, whereas matriptase immunoreactivity was enhanced with SCC progression. We could also show that matriptase was complexed to HAI-1 in normal human skin, whereas in SCCs, the enzyme was present in an unassociated form. Both a specific peptide agonist for PAR 2 and the Proteinase domain of matriptase were able to induce intracellular calcium mobilization and inhibition of proliferation in cultured HaCaT keratinocytes. In conclusion, our results suggest that PAR 2 is a substrate for matriptase in human skin in vivo. Deregulation of these proteins delineates SCC progression.
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activation of Proteinase Activated Receptor 2 by human kallikrein related peptidases
Journal of Investigative Dermatology, 2008Co-Authors: Kristina Stefansson, Martin Steinhoff, Maria Brattsand, Dirk Roosterman, Cordula Kempkes, Georgeta Bocheva, Torbjorn EgelrudAbstract:Proteinase-Activated Receptor-2 (PAR2) is a seven transmembrane spanning, G-protein-coupled Receptor, present on the membrane of many cell types including keratinocytes. In skin, PAR2 is suggested to play a regulatory role during inflammation, epidermal barrier function, and pruritus. PAR2 is Activated by trypsin-like proteases by a unique mechanism where cleavage of the Receptor leads to the release of a small peptide, which activates the Receptor as a tethered ligand. The endogenous activators of PAR2 on keratinocytes have not been identified as of yet. Potential candidates are kallikrein-related peptidases (KLKs) expressed by epidermal cells. Therefore, the ability of four human skin-derived KLKs was examined with regard to their capacity to activate PAR2 in vitro. PAR2 cleavage was followed by immunofluorescence analysis and functional activation by measurements of changes in intracellular calcium levels. We found that KLK5 and KLK14, but neither KLK7 nor KLK8, induced PAR2 signalling. We conclude that certain, but not all, epidermal KLKs are capable of activating PAR2. We could also show the coexpression of KLK14 and PAR2 Receptor in inflammatory skin disorders. These in vitro results suggest that KLKs may take part in PAR2 activation in the epidermis and thereby in PAR2-mediated inflammatory responses, including epidermal barrier repair and pruritus. The role of KLKs in PAR2 activation in vivo remains to be elucidated.
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a role for Proteinase Activated Receptor 1 in inflammatory bowel diseases
Journal of Clinical Investigation, 2004Co-Authors: Nathalie Vergnolle, Martin Steinhoff, Nigel W. Bunnett, Laurie Cellars, Andrea Mencarelli, Giovanni Rizzo, Sunita Swaminathan, Paul L Beck, Patricia Andradegordon, Morley D. HollenbergAbstract:Proteinase-Activated Receptor-1 (PAR1), a G protein-coupled Receptor Activated by thrombin, is highly expressed in different cell types of the gastrointestinal tract. The activity of thrombin and of other Proteinases is significantly increased in the colon of inflammatory bowel disease (IBD) patients. Since PAR1 activation in tissues other than the gut provoked inflammation, we hypothesized that PAR1 activation in the colon is involved in the pathogenesis of IBD. Here, we demonstrate that PAR1 is overexpressed in the colon of IBD patients. In mice, intracolonic administration of PAR1 agonists led to an inflammatory reaction characterized by edema and granulocyte infiltration. This PAR1 activation-induced inflammation was dependent on B and T lymphocytes. Moreover, PAR1 activation exacerbated and prolonged inflammation in a mouse model of IBD induced by the intracolonic administration of trinitrobenzene sulfonic acid (TNBS), while PAR1 antagonism significantly decreased the mortality and severity of colonic inflammation induced by TNBS and dextran sodium sulfate. In these 2 models, colitis development was strongly attenuated by PAR1 deficiency. Taken together, these results imply an important role for PAR1 in the pathogenesis of experimental colitis, supporting the notion that PAR1 inhibition may be beneficial in the context of IBD and possibly in other chronic intestinal inflammatory disorders.
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Colitis induced by Proteinase-Activated Receptor-2 agonists is mediated by a neurogenic mechanism
Canadian journal of physiology and pharmacology, 2003Co-Authors: Cathy Nguyen, Morley D. Hollenberg, John L. Wallace, Steven J. Compton, Nicolas Cenac, Anne-marie Coelho, Lionel Bueno, Eileen F. Grady, Rafael Garcia-villar, Martin SteinhoffAbstract:Proteinase-Activated Receptor-2 (PAR2) activation induces colonic inflammation by an unknown mechanism. We hypothesized that PAR2 agonists administered intracolonically in mice induce inflammation via a neurogenic mechanism. Pretreatment of mice with neurokinin-1 and calcitonin-gene-related peptide (CGRP) Receptor antagonists or with capsaicin showed attenuated PAR2-agonist-induced colitis. Immunohistochemistry demonstrated a differential expression of a marker for the type-1 CGRP Receptor during the time course of PAR2-agonist-induced colitis, further suggesting a role for CGRP. We conclude that PAR2-agonist-induced intestinal inflammation involves the release of neuropeptides, which by acting on their Receptors cause inflammation. These results implicate PAR2 as an important mediator of intestinal neurogenic inflammation.Key words: trypsin, Proteinase-Activated Receptor-2, colitis, neurogenic inflammation, substance P, neurokinin-1 Receptors, calcitonin-gene-related peptide.
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Proteinase Activated Receptor 2 mediates itch a novel pathway for pruritus in human skin
The Journal of Neuroscience, 2003Co-Authors: Martin Steinhoff, Thomas A. Luger, Ulrich Neisius, Akihiko Ikoma, Manige Fartasch, G Heyer, Per Stahl Skov, Martin SchmelzAbstract:We examined whether neuronal Proteinase-Activated Receptor-2 (PAR-2) may be involved in pruritus of human skin. The endogenous PAR-2 agonist tryptase was increased up to fourfold in atopic dermatitis (AD) patients. PAR-2 was markedly enhanced on primary afferent nerve fibers in skin biopsies of AD patients. Intracutaneous injection of endogenous PAR-2 agonists provoked enhanced and prolonged itch when applied intralesionally. Moreover, itch upon mast cell degranulation was abolished by local antihistamines in controls but prevailed in AD patients. Thus, we identified enhanced PAR-2 signaling as a new link between inflammatory and sensory phenomena in AD patients. PAR-2 therefore represents a promising therapeutic target for the treatment of cutaneous neurogenic inflammation and pruritus.
