α1-Adrenergic and cholinergic agonists activate MAPK by separate mechanisms to inhibit secretion in lacrimal gland

2003 ◽  
Vol 284 (1) ◽  
pp. C168-C178 ◽  
Author(s):  
Isao Ota ◽  
Driss Zoukhri ◽  
Robin R. Hodges ◽  
José D. Rios ◽  
Vanja Tepavcevic ◽  
...  
Keyword(s):  
Protein Secretion ◽  
Lacrimal Gland ◽  
Egf Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Signaling Mechanisms ◽  
Mitogen Activated Protein ◽  
Secretion Inhibition

The purpose of this study was to determine the role of p42/p44 mitogen-activated protein kinase (MAPK) in α1-adrenergically and cholinergically stimulated protein secretion in rat lacrimal gland acinar cells and the pathways used by these agonists to activate MAPK. Acini were isolated by collagenase digestion and incubated with the α1-adrenergic agonist phenylephrine or the cholinergic agonist carbachol, and activation of MAPK and protein secretion were then measured. Phenylephrine and carbachol activated MAPK in a time- and concentration-dependent manner. Inhibition of MAPK significantly increased phenylephrine- and carbachol-induced protein secretion. Inhibition of EGF receptor (EGFR) with AG1478, an inhibitor of the EGFR tyrosine kinase activity, significantly increased phenylephrine- but not carbachol-induced protein secretion. Whereas phenylephrine-induced activation of MAPK was completely inhibited by AG1478, activation of MAPK by carbachol was not. Phenylephrine stimulated tyrosine phosphorylation of the EGFR, whereas carbachol stimulated p60Src, and possibly Pyk2, to activate MAPK. We conclude that, in the lacrimal gland, activation of MAPK plays an inhibitory role in α1-adrenergically and cholinergically stimulated protein secretion and that these agonists use different signaling mechanisms to activate MAPK.

Role of cAMP inhibition of p44/p42 mitogen-activated protein kinase in potentiation of protein secretion in rat lacrimal gland

2007 ◽  
Vol 293 (5) ◽  
pp. C1551-C1560 ◽  
Author(s):  
Chika Funaki ◽  
Robin R. Hodges ◽  
Darlene A. Dartt
Keyword(s):  
Protein Kinase ◽  
Protein Secretion ◽  
Lacrimal Gland ◽  
Mitogen Activated Protein Kinase ◽  
Adrenergic Agonist ◽  
Mapk Activity ◽  
Mitogen Activated Protein ◽  
Epidermal Growth ◽  
Camp Levels

We previously found that addition of cAMP and a Ca2+/PKC-dependent agonist causes synergism or potentiation of protein secretion from rat lacrimal gland acini. In the present study we determined whether cAMP decreases p44/p42 mitogen-activated protein kinase (MAPK) activity in the lacrimal gland. Since we know that activation of MAPK attenuates protein secretion stimulated by Ca2+- and PKC-dependent agonists, we also determined whether this activation causes potentiation of secretion. Freshly prepared rat lacrimal gland acinar cells were incubated with dibutyryl cAMP (DBcAMP), carbachol (a cholinergic agonist), phenylephrine (an α1-adrenergic agonist), or epidermal growth factor (EGF). The latter three agonists are known to activate p44/p42 MAPK. p44/p42 MAPK activity and protein secretion were measured. As measured by Western blot analysis, DBcAMP inhibited both basal and agonist-stimulated p44/p42 MAPK activity. Cellular cAMP levels were increased by 1) using two different cell-permeant cAMP analogs, 2) activating adenylyl cyclase (L-858051), or 3) activation of Gs-coupled receptors (VIP). The cell-permeant cAMP analogs, L-858051, and VIP inhibited basal p44/p42 MAPK activity by 50, 40, and 40%, respectively. DBcAMP and VIP inhibited carbachol- and EGF-stimulated MAPK activity. cAMP, but not VIP, inhibited phenylephrine-stimulated MAPK activity. Potentiation of secretion was detected when carbachol, phenylephrine, or EGF was simultaneously added with DBcAMP. We conclude that increasing cellular cAMP levels inhibits p44/p42 MAPK activity and that this could account for potentiation of secretion obtained when cAMP was elevated and Ca2+ and PKC were increased by agonists.

Novel regulation of adrenomedullin receptor by PDGF: role of receptor activity modifying protein-3

2002 ◽  
Vol 282 (6) ◽  
pp. C1322-C1331 ◽  
Author(s):  
Wojciech Nowak ◽  
Narayanan Parameswaran ◽  
Carolyn S. Hall ◽  
Nambi Aiyar ◽  
Harvey V. Sparks ◽  
...  
Keyword(s):  
Mesangial Cells ◽  
Receptor Activity ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Calcitonin Receptor ◽  
Concentration Dependent Manner ◽  
Adrenomedullin Receptor ◽  
Mitogen Activated Protein ◽  
Functional Receptor

Receptor activity modifying protein-3 (RAMP-3) has been shown to complex with the calcitonin receptor-like receptor, establishing a functional receptor for adrenomedullin (AM). AM exhibits potent antiproliferative and antimigratory effects on rat mesangial cells (RMCs). In this study we investigated the effect of platelet-derived growth factor (PDGF) on RAMP-3 expression in RMCs. We show here that PDGF-BB stimulates RAMP-3 mRNA expression in a concentration-dependent manner. Pretreatment with actinomycin-D and α-amanitin demonstrates that this effect is independent of new RNA synthesis. Furthermore, PDGF increased the half-life of RAMP-3 mRNA from 66.5 to 331.6 min. Using selective inhibitors, our results also indicate that the increase in RAMP-3 mRNA is mitogen-activated protein kinase (MAPK) kinase (MEK)/MAPK and p38 MAPK dependent. PDGF also caused a corresponding elevation in membrane-associated RAMP-3 protein. Associated with this increase, PDGF pretreatment led to a significantly higher AM-mediated adenylate cyclase activity, suggesting a functional consequence for the PDGF-induced increase in RAMP-3 expression. Taken together, these data identify PDGF-dependent regulation of RAMP-3 expression as a possible mechanism for modulating the responsiveness of the mesangial cell to AM.

scholarly journals The MAPK Hog1p Modulates Fps1p-dependent Arsenite Uptake and Tolerance in Yeast

2006 ◽  
Vol 17 (10) ◽  
pp. 4400-4410 ◽  
Author(s):  
Michael Thorsen ◽  
Yujun Di ◽  
Carolina Tängemo ◽  
Montserrat Morillas ◽  
Doryaneh Ahmadpour ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Transcriptional Response ◽  
Mitogen Activated Protein Kinase ◽  
Regulatory Mechanisms ◽  
Signaling Mechanisms ◽  
Mitogen Activated Protein ◽  
Detoxification Systems ◽  
Arsenic Sensing

Arsenic is widely distributed in nature and all organisms possess regulatory mechanisms to evade toxicity and acquire tolerance. Yet, little is known about arsenic sensing and signaling mechanisms or about their impact on tolerance and detoxification systems. Here, we describe a novel role of the S. cerevisiae mitogen-activated protein kinase Hog1p in protecting cells during exposure to arsenite and the related metalloid antimonite. Cells impaired in Hog1p function are metalloid hypersensitive, whereas cells with elevated Hog1p activity display improved tolerance. Hog1p is phosphorylated in response to arsenite and this phosphorylation requires Ssk1p and Pbs2p. Arsenite-activated Hog1p remains primarily cytoplasmic and does not mediate a major transcriptional response. Instead, hog1Δ sensitivity is accompanied by elevated cellular arsenic levels and we demonstrate that increased arsenite influx is dependent on the aquaglyceroporin Fps1p. Fps1p is phosphorylated on threonine 231 in vivo and this phosphorylation critically affects Fps1p activity. Moreover, Hog1p is shown to affect Fps1p phosphorylation. Our data are the first to demonstrate Hog1p activation by metalloids and provides a mechanism by which this kinase contributes to tolerance acquisition. Understanding how arsenite/antimonite uptake and toxicity is modulated may prove of value for their use in medical therapy.

scholarly journals Role of EGF Receptor Regulatory Networks in the Host Response to Viral Infections

2022 ◽  
Vol 11 ◽  
Author(s):  
Cathleen R. Carlin
Keyword(s):  
Regulatory Networks ◽  
Egf Receptor ◽  
Viral Infections ◽  
Mitogen Activated Protein Kinase ◽  
Egfr Ligands ◽  
Gene Therapy Vectors ◽  
Mitogen Activated Protein ◽  
Cellular Stresses ◽  
And Function

In this review article, we will first provide a brief overview of EGF receptor (EGFR) structure and function, and its importance as a therapeutic target in epithelial carcinomas. We will then compare what is currently known about canonical EGFR trafficking pathways that are triggered by ligand binding, versus ligand-independent pathways activated by a variety of intrinsic and environmentally induced cellular stresses. Next, we will review the literature regarding the role of EGFR as a host factor with critical roles facilitating viral cell entry and replication. Here we will focus on pathogens exploiting virus-encoded and endogenous EGFR ligands, as well as EGFR-mediated trafficking and signaling pathways that have been co-opted by wild-type viruses and recombinant gene therapy vectors. We will also provide an overview of a recently discovered pathway regulating non-canonical EGFR trafficking and signaling that may be a common feature of viruses like human adenoviruses which signal through p38-mitogen activated protein kinase. We will conclude by discussing the emerging role of EGFR signaling in innate immunity to viral infections, and how viral evasion mechanisms are contributing to our understanding of fundamental EGFR biology.

scholarly journals Anti-Photoaging and Anti-Melanogenesis Effects of Fucoidan Isolated from Hizikia fusiforme and Its Underlying Mechanisms

Marine Drugs ◽  
2020 ◽  
Vol 18 (8) ◽  
pp. 427 ◽  
Author(s):  
Lei Wang ◽  
Jae-Young Oh ◽  
Young-Sang Kim ◽  
Hyo-Geun Lee ◽  
Jung-Suck Lee ◽  
...  
Keyword(s):  
Human Keratinocytes ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Hacat Cells ◽  
Concentration Dependent Manner ◽  
B16f10 Cells ◽  
Hizikia Fusiforme ◽  
Mitogen Activated Protein ◽  
Underlying Mechanisms ◽  
Induced Apoptosis

Previous studies suggested that fucoidan with a molecular weight of 102.67 kDa, isolated from Hizikia fusiforme, possesses strong antioxidant activity. To explore the cosmeceutical potential of fucoidan, its anti-photoaging and anti-melanogenesis effects were evaluated in the present study. The anti-photoaging effect was investigated in ultraviolet (UV) B-irradiated human keratinocytes (HaCaT cells), where fucoidan effectively reduced the intracellular reactive oxygen species level and improved the viability of the UVB-irradiated cells without any cytotoxic effects. Moreover, fucoidan significantly decreased UVB-induced apoptosis in HaCaT cells by regulating the protein expression of Bax, Bcl-xL, PARP, and Caspase-3 in HaCaT cells in a concentration-dependent manner. The anti-melanogenesis effect of fucoidan was evaluated in B16F10 melanoma cells that had been stimulated with alpha-melanocyte-stimulating hormone (α-MSH), and fucoidan treatment remarkably inhibited melanin synthesis in α-MSH-stimulated B16F10 cells. Further studies indicated that fucoidan significantly suppressed the expression of tyrosinase and tyrosinase-related protein-1 and -2 (TRP-1 and-2) in B16F10 cells by down-regulating microphthalmia-associated transcription factor (MITF) through regulation of the ERK–MAPK (extracellular signal regulated kinase-mitogen activated protein kinase) pathway. Taken together, these results suggest that fucoidan isolated from H. fusiforme possesses strong anti-photoaging and anti-melanogenesis activities and can be used as an ingredient in the pharmaceutical and cosmeceutical industries.

THE CENTRAL ROLE OF EGF RECEPTOR BLOCKADE IN THE INHIBITION OF MITOGEN-ACTIVATED PROTEIN KINASE PATHWAYS

1999 ◽  
pp. 132
Author(s):  
Thomas Putz ◽  
Zoran Culig ◽  
Iris E. Eder ◽  
Claudia Nessler-Menardi ◽  
Georg Bartsch ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Egf Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Receptor Blockade ◽  
Mitogen Activated Protein

Vasoactive intestinal polypeptide stimulation of protein secretion from rat lacrimal gland acini

1984 ◽  
Vol 247 (5) ◽  
pp. G502-G509 ◽  
Author(s):  
D. A. Dartt ◽  
A. K. Baker ◽  
C. Vaillant ◽  
P. E. Rose
Keyword(s):  
Protein Secretion ◽  
Vasoactive Intestinal Polypeptide ◽  
Lacrimal Gland ◽  
Maximum Concentration ◽  
Nerve Fibers ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Camp Content ◽  
Cholinergic Antagonist ◽  
Intestinal Polypeptide

The effect of vasoactive intestinal polypeptide (VIP) on protein secretion from lacrimal gland was investigated by using acini prepared by collagenase digestion of rat exorbital lacrimal glands. Protein secretion was determined by incubating the acini for 0-40 min and analyzing the supernatant for peroxidase, a protein secreted by the rat exorbital lacrimal gland. VIP (10(-10) to 10(-7) M) stimulated secretion in a concentration-dependent manner. A maximum concentration of VIP (10(-8) M) stimulated secretion to the same extent as a maximum concentration of carbachol (10(-5) M). The cholinergic antagonist atropine at a concentration (10(-5) M) that completely abolished carbachol-induced secretion did not alter VIP-stimulated secretion. The secretory effects of maximal concentrations of VIP and carbachol were additive, but decreasing the carbachol concentration potentiated secretion. Unlike carbachol, which had no effect on the acinar cAMP level, VIP increased cAMP content sixfold. Immunohistochemical staining demonstrated VIP-like immunoreactivity in nerve fibers throughout the gland, distributed primarily around acini. We conclude that VIP-like immunoreactive nerves are present in the lacrimal gland and that VIP can stimulate protein secretion but utilizes a pathway separate from, but convergent with, that used by cholinergic agonists.

Sphingosine Blocks Human Polymorphonuclear Leukocyte Phagocytosis Through Inhibition of Mitogen-Activated Protein Kinase Activation

Blood ◽  
1999 ◽  
Vol 93 (2) ◽  
pp. 686-693 ◽  
Author(s):  
Evelin M.B. Raeder ◽  
Pamela J. Mansfield ◽  
Vania Hinkovska-Galcheva ◽  
Lars Kjeldsen ◽  
James A. Shayman ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Polymorphonuclear Leukocyte ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Human Polymorphonuclear Leukocyte ◽  
Calcium Dependent ◽  
Mitogen Activated Protein ◽  
Erk2 Activation

Abstract In the present study, we investigated the mechanism by which sphingosine and its analogues, dihydrosphingosine and phytosphingosine, inhibit polymorphonuclear leukocyte (PMN) phagocytosis of IgG-opsonized erythrocytes (EIgG) and inhibit ERK1 and ERK2 phosphorylation. We used antibodies that recognized the phosphorylated forms of ERK1 (p44) and ERK2 (p42) (extracellular signal-regulated protein kinases 1 and 2). Sphingoid bases inhibited ERK1 and ERK2 activation and phagocytosis of EIgG in a concentration-dependent manner. Incubation with glycine, N,N′-[1,2-ethanediylbis(oxy-2,1-phenylene)]bis[N-[2-[(acetyloxy)methoxy]-2-oxoethyl]]-bis[(acetyloxy)methyl]ester (BAPTA,AM), an intracellular chelator of calcium, failed to block either phagocytosis or ERK1 and ERK2 phosphorylation, consistent with the absence of a role for a calcium-dependent protein kinase C (PKC) in ERK1 and ERK2 phosphorylations. Western blotting demonstrated that sphingosine inhibited the translocation of Raf-1 and PKCδ from PMN cytosol to the plasma membrane during phagocytosis. These data are consistent with the interpretation that sphingosine regulates ERK1 and ERK2 phosphorylation through inhibition of PKCδ, and this in turn leads to inhibition of Raf-1 translocation to the plasma membrane. Consistent with this interpretation, the sphingosine-mediated inhibition of phagocytosis, ERK2 activation, and PKCδ translocation to the plasma membrane could be abrogated with a cell-permeable diacylglycerol analog. The increase in the diacylglycerol mass correlated with the translocation of PKCδ and Raf-1 to the plasma membrane by 3 minutes after the initiation of phagocytosis. Additionally, the diacylglycerol analog enhanced phagocytosis by initiating activation of PKCδ and its translocation to the plasma membrane. Because PMN generate sufficient levels of sphingosine by 30 minutes during phagocytosis of EIgG to inhibit phagocytosis, it appears that sphingosine can serve as an endogenous regulator of EIgG-mediated phagocytosis by downregulating ERK activation.

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