Opioid growth factor is present in human and mouse gastrointestinal tract and inhibits DNA synthesis

1997 ◽  
Vol 272 (4) ◽  
pp. R1094-R1104
Author(s):  
I. S. Zagon ◽  
Y. Wu ◽  
P. J. McLaughlin
Keyword(s):  
Circadian Rhythm ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Dna Synthesis ◽  
Opioid Antagonist ◽  
Receptor Interaction ◽  
Esophageal Epithelium ◽  
Endogenous Opioid ◽  
Endogenous Opioid Peptide ◽  
Opioid Growth Factor

Native opioid peptides serve as growth factors in a number of normal and neoplastic cells and tissues. This study investigated the influence of opioids on circadian rhythm-dependent DNA synthesis in mouse esophagus during homeostatic renewal. In contrast to a labeling index (LI) of 24.0% at 0630 and 5.5% at 1600, disruption of opioid-receptor interaction by the potent opioid antagonist naltrexone hydrochloride (NTX; 10 mg/kg) in mice resulted in an elevation of 49% in DNA synthesis of esophageal epithelial cells at 1600, but had no effect at 0630. Mice subjected to [Met5]enkephalin (1 mg/kg) had an LI that was decreased 23% from control levels at 0630, but was unaffected at 1600. This decrease in DNA synthesis was blocked by concomitant administration of naloxone (10 mg/kg); naloxone alone had no influence on cell replicative processes. In tissue culture studies, NTX and OGF markedly increased and decreased, respectively, the LI from control values. Both opioid growth factor (OGF) and its receptor, zeta, were detected in all but the cornified layer of mouse esophageal epithelium and in the epithelial cells of the stomach and small and large intestines. In addition, both peptide and receptor were observed in the basal and suprabasal cells of human esophageal epithelium. These results indicate that an endogenous opioid peptide (OGF) and its receptor (zeta) reside in gastrointestinal epithelium and play a role in cellular renewal processes in a tonically inhibitory, direct, and circadian rhythm-dependent fashion.

Opioid growth factor inhibits DNA synthesis in mouse tongue epithelium in a circadian rhythm-dependent manner

1994 ◽  
Vol 267 (3) ◽  
pp. R645-R652 ◽  
Author(s):  
I. S. Zagon ◽  
Y. Wu ◽  
P. J. McLaughlin
Keyword(s):  
Circadian Rhythm ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Opioid Peptide ◽  
Endogenous Opioids ◽  
Opioid Antagonist ◽  
Dependent Manner ◽  
Endogenous Opioid ◽  
Endogenous Opioid Peptide ◽  
Opioid Growth Factor

In addition to neuromodulation, endogenous opioids also serve as growth factors. To investigate the involvement of the naturally occurring opioid peptide [Met5]enkephalin [termed opioid growth factor (OGF)] in the renewal of epithelium, adult mice were given systemic injections of OGF (1 mg/kg) and examined 2 h later at 0700 or 1700 h. DNA synthesis in the tongue was investigated using [3H]thymidine and autoradiography. OGF depressed DNA synthesis of the basal epithelial cells in the tip, and dorsal and ventral surfaces of the tongue (42-44% of control levels) only at 0700 h. This decrease in DNA synthesis was blocked by concomitant administration of the opioid antagonist naloxone (10 mg/kg); naloxone alone had no influence on cell replicative processes. Both OGF and its receptor, zeta (zeta), were detected in the stratified squamous epithelium of the ventral and dorsal surfaces of the tongue by immunocytochemistry. Photodensitometric measurements of immunocytochemical preparations revealed almost twofold more OGF and zeta-receptor immunoreactivity at 1700 h than at 0700 h. These results indicate that an endogenous opioid peptide and its receptor are present and govern cellular renewal processes in the tongue and regulate DNA synthesis in a circadian rhythm-dependent fashion.

Opioid growth factor modulates corneal epithelial outgrowth in tissue culture

1995 ◽  
Vol 268 (4) ◽  
pp. R942-R950 ◽  
Author(s):  
I. S. Zagon ◽  
J. W. Sassani ◽  
P. J. McLaughlin
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Opioid Receptor ◽  
Corneal Epithelium ◽  
Labeling Index ◽  
Opioid Antagonist ◽  
Receptor Interaction ◽  
Endogenous Opioid ◽  
Endogenous Opioid Peptide ◽  
Opioid Growth Factor

In addition to neuromodulation, endogenous opioid peptides serve as growth factors. To determine involvement of opioids in the homeostatic renewal and repair of the corneal epithelium, epithelial outgrowths from 3-mm explants of rabbit cornea were investigated. Blockade of opioid-receptor interaction by the potent opioid antagonist naltrexone (NTX) for 7 days significantly increased the extent of outgrowths and the number and labeling index (DNA synthesis) of epithelial cells, relative to control levels. Outgrowths exposed to the opioid growth factor (OGF) [Met5]enkephalin for 7 days were subnormal in extent and labeling index and displayed alterations in architectural pattern. The effects of OGF on epithelial outgrowth were blocked by concomitant exposure to the opioid antagonist naloxone; naloxone alone had no effect on growth at the concentration utilized. NTX and OGF were active in both serum-containing and serum-free cultures. Immunocytochemical investigations showed that both OGF and its opioid receptor zeta (zeta) were present in epithelial cells growing in control media. The results indicate that an endogenous opioid peptide and its receptor are present in mammalian corneal epithelium and serve to modulate cell proliferation, migration, and organization.

Ontogeny of the opioid growth factor, [Met5]-enkephalin, and its binding activity in the rat retina

1995 ◽  
Vol 12 (5) ◽  
pp. 939-950 ◽  
Author(s):  
Tomoki Isayama ◽  
W. Jeffrey Hurst ◽  
Patricia J. McLaughlin ◽  
Ian S. Zagon
Keyword(s):  
Growth Factor ◽  
Dna Synthesis ◽  
High Performance ◽  
Opioid Peptide ◽  
Binding Activity ◽  
Endogenous Opioid ◽  
Endogenous Opioid Peptide ◽  
Rat Retina ◽  
Opioid Growth Factor

AbstractThe endogenous opioid peptide [Met5]-enkephalin is a tonically active opioid growth factor (OGF) with an inhibitory action on DNA synthesis in the developing rat retina. In this study, the ontogeny of the spatial and temporal expression of OGF and its binding activity was examined. OGF-like immunoreactivity was detected in the retina at gestation day (E) 20, but not at E18, and was localized to ganglion cell and neuroblast layers; immunochemical reaction was no longer seen in the retina by postnatal day 6. Native OGF was further identified and characterized by high-performance liquid chromatography (HPLC) studies and immunodot assays, which revealed that [Met5]-enkephalin was present in the neonatal, but not adult, rat retina. OGF binding activity was detected as early as E18 using [125I]-[Met5]-enkephalin and in vitro receptor autoradiography. Little OGF binding activity was noted for prenatal retinas, but appreciable activity was observed from birth to postnatal day 4; no OGF binding could be detected after postnatal day 5 or in the adult. These results reveal the transient appearance of the OGF, [Met5]-enkephalin, and its receptor binding activity in the developing mammalian retina, and show that their ontogeny coincides with the timetable of DNA synthesis of retinal neuroblasts.

scholarly journals Internalization of the opioid growth factor, [Met5]-enkephalin, is dependent on clathrin-mediated endocytosis for downregulation of cell proliferation

2010 ◽  
Vol 299 (3) ◽  
pp. R774-R785 ◽  
Author(s):  
Fan Cheng ◽  
Patricia J. McLaughlin ◽  
William A. Banks ◽  
Ian S. Zagon
Keyword(s):  
Cell Proliferation ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Wound Repair ◽  
Opioid Antagonist ◽  
Live Cells ◽  
Inhibitory Peptide ◽  
African Green Monkey Kidney ◽  
Initial Exposure ◽  
Opioid Growth Factor

The opioid growth factor (OGF; [Met5]-enkephalin), a constitutively expressed and tonically active inhibitory peptide, interacts with the OGF receptor (OGFr) to form an endogenous growth-regulating pathway in homeostasis. Amplification of OGF-OGFr interfacing in animal and clinical studies depresses development, neoplasia, angiogenesis, and immunity. Disruption of the OGF-OGFr axis accelerates cell proliferation and has been particularly important in wound repair. To investigate how OGF enters cells, OGF was labeled with 5,6-tetramethylrhodamine OGF (RhoOGF) to study its uptake in live cells. African green monkey kidney cells (COS-7) incubated with RhoOGF exhibited a temperature-dependent course of entry, being internalized at 37°C but not at 4°C. RhoOGF was detected in the cytoplasm 15 min after initial exposure, observed in both cytoplasm and nucleus within 30 min, and remained in the cells for as long as 5 h. A 100-fold excess of OGF or the opioid antagonist naltrexone, but not other opioid ligands (some selective for classic opioid receptors), markedly reduced entry of RhoOGF into cells. RhoOGF was functional because DNA synthesis in cells incubated with RhoOGF (10−5 to 10−8 M) was decreased 24–36%, and was comparable to cells treated with unlabeled OGF (reductions of 26–39%). OGF internalization was dependent on clathrin-mediated endocytosis, with addition of clathrin siRNA diminishing the uptake of RhoOGF and upregulating DNA synthesis. RhoOGF clathrin-mediated endocytosis was unrelated to endosomal or Golgi pathways. Taken together, these results suggest that OGF enters cells by active transport in a saturable manner that requires clathrin-mediated endocytosis.

Opioid growth factor-dependent DNA synthesis in the neonatal rat aorta

1996 ◽  
Vol 270 (1) ◽  
pp. R22-R32
Author(s):  
I. S. Zagon ◽  
Y. Wu ◽  
P. J. McLaughlin
Keyword(s):  
Growth Factors ◽  
Growth Factor ◽  
Dna Synthesis ◽  
Cell Types ◽  
Opioid Peptide ◽  
Endogenous Opioids ◽  
Negative Regulator ◽  
Neonatal Rat ◽  
Endogenous Opioid Peptide ◽  
Opioid Growth Factor

In addition to neuromodulation, endogenous opioids serve as growth factors in neural and nonneural cells. This study examined the hypothesis that opioids are inhibitory growth factors in vascular development. No circadian rhythm was detected for DNA synthesis in endothelial, smooth muscle, or fibroblast cells in the aorta of 1-day-old rats. Administration of naltrexone (NTX), a potent opioid antagonist, markedly increased the labeling indexes of all three cell types. [Met5]enkephalin, found to be the only opioid peptide to influence DNA synthesis and termed the opioid growth factor (OGF), depressed DNA synthesis in each cell type for 4-6 h in a dose-dependent and receptor-mediated manner. In aortas placed in tissue culture, DNA synthesis was significantly increased by incubation in NTX and decreased by incubation with OGF, Both OGF and its receptor, zeta (zeta), were associated with the cytoplasm of all three cell types in the neonatal aorta. These results indicate that an endogenous opioid peptide (i.e., OGF) and its receptor (i.e., zeta) reside in the developing vascular cells and govern DNA synthesis, with OGF acting directly as a tonic negative regulator of cell generation in the great vessels.

Seasonal and steroid-dependent effects on the modulation of LH secretion in the ewe by intracerebroventricularly administered β-endorphin or naloxone

1989 ◽  
Vol 122 (2) ◽  
pp. 509-517 ◽  
Author(s):  
R. J. E. Horton ◽  
H. Francis ◽  
I. J. Clarke
Keyword(s):  
Breeding Season ◽  
Luteal Phase ◽  
Pulse Frequency ◽  
Opioid Peptide ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Opioid Antagonist ◽  
Endogenous Opioid ◽  
Endogenous Opioid Peptide ◽  
Lh Secretion

ABSTRACT The natural opioid ligand, β-endorphin, and the opioid antagonist, naloxone, were administered intracerebroventricularly (i.c.v.) to evaluate effects on LH secretion in ovariectomized ewes and in ovariectomized ewes treated with oestradiol-17β plus progesterone either during the breeding season or the anoestrous season. Ovary-intact ewes were also studied during the follicular phase of the oestrous cycle. Jugular blood samples were taken at 10-min intervals for 8 h and either saline (20–50 μl), 100 μg naloxone or 10 μg β-endorphin were injected i.c.v. after 4 h. In addition, luteal phase ewes were injected i.c.v. with 25 μg β-endorphin(1–27), a purported endogenous opioid antagonist. In ovariectomized ewes, irrespective of season, saline and naloxone did not affect LH secretion, but β-endorphin decreased the plasma LH concentrations, by reducing LH pulse frequency. The effect of β-endorphin was blocked by administering naloxone 30 min beforehand. Treating ovariectomized ewes with oestradiol-17β plus progesterone during the breeding season reduced plasma LH concentrations from 6–8 μg/l to less than 1 μg/l. In these ewes, saline did not alter LH secretion, but naloxone increased LH pulse frequency and the plasma concentrations of LH within 15–20 min. During anoestrus, the combination of oestradiol-17β plus progesterone to ovariectomized ewes reduced the plasma LH concentrations from 3–5 μg/l to undetectable levels, and neither saline nor naloxone affected LH secretion. During the follicular phase of the oestrous cycle, naloxone enhanced LH pulse frequency, which resulted in increased plasma LH concentrations; saline had no effect. In these sheep, β-endorphin decreased LH pulse frequency and the mean concentrations of LH, and this effect was prevented by the previous administration of naloxone. The i.c.v. administration of β-endorphin(1–27) to luteal phase ewes did not affect LH secretion. These data demonstrate the ability of a naturally occurring opioid peptide to inhibit LH secretion in ewes during the breeding and non-breeding seasons, irrespective of the gonadal steroid background. In contrast, whilst the gonadal steroids suppress LH secretion in ovariectomized ewes during both seasons, they only appear to activate endogenous opioid peptide (EOP)-mediated inhibition of LH secretion during the breeding season. Furthermore, these data support the notion that LH secretion in ovariectomized ewes is not normally under the control of EOP, so that naloxone has no effect. Journal of Endocrinology (1989) 122, 509–517

scholarly journals Effects of Local Opioid Antagonist on Diabetic Fracture Rat Model

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0017
Author(s):  
Jarrett D. Cain ◽  
Michelle Titunick ◽  
Patricia McLaughlin ◽  
Ian Zagon
Keyword(s):  
Growth Factor ◽  
Fracture Healing ◽  
Bone Healing ◽  
Calcium Sulfate ◽  
Bone Fractures ◽  
Diabetic Rats ◽  
Receptor Expression ◽  
Opioid Antagonist ◽  
Diabetic Patients ◽  
Opioid Growth Factor

Category: Diabetes Introduction/Purpose: Complications associated with the diabetes include increased incidence of fracture healing, delayed fracture healing, delayed osteoblasts cell replication, decreased angiogenesis, migration and/or osteoblast cell differentiation. The cellular events involved in bone healing are adversely affected by diabetes; however, can be modulated by the Opioid Growth Factor (OGF)–OGF receptor (OGFr) is an inhibitory peptide that downregulates DNA synthesis in a tissue nonspecific manner. Diabetes is associated with elevated serum levels of OGF and dysregulation of the OGFr leading to multiple complications related to healing, sensitivity, and regeneration. This study explores the presence and function of the OGF-OGFr axis in bone tissue from type 1 diabetic rats examining intact and fractured femurs during early phases of the repair process Methods: Seven-week-old Sprague Dawley rats were injected with streptozotocin (40mg/kg i.p.) to induce T1D; other rats received buffer only and served as controls. After one month, hyperglycemia rats underwent surgery to produce a fracture at the distal third of the femur. Four diabetic rats received opioid antagoinist (naltrexone) and calcium sulfate and all remaining rats received calcium sulfate with water only. X-rays were taken immediately after surgery and after rats were euthanized on post-surgery; femur and tibia were collected for protein isolation, western blot analysis along with frozen or paraffin-embedded for histological analysis Results: Immunofluorescence indicated approximately 90% increase in opioid growth factor receptor expression in diabetic femurs compared to age-matched normal femurs. Western Blotting also suggested an increase in the receptor protein in diabetic bones relative to normal bone. TRAP staining for osteoclasts was greater in control and opioid antagonist-treated diabetic fractures when compared to the number of osteoclasts in vehicle-treated diabetic fractured femurs. Safranin O stained sections revealed approximately more bone in opioid growth receptor antagonist-treated diabetic bone fractures than in vehicle-treated bone fractures Conclusion: These data support our hypothesis that expression levels of OGFr are dysregulated in the bone of diabetic patients leading to complications in bone healing. Moreover, modulation of the OGF-OGFr pathway with receptor antagonists restored some aspects of bone healing. With further study, these preliminary results support the role of the OGF-OGFr axis in treatment of diabetic bone healing. New therapies to target dysregulation of the OGF-OGFr regulatory pathway in diabetes would provide a safe and effective disease-modifying treatment for delayed bone healing.

Membrane receptor location defines receptor interaction with signaling proteins in a polarized epithelium

1999 ◽  
Vol 276 (1) ◽  
pp. C91-C101 ◽  
Author(s):  
Kurt Amsler ◽  
Scott K. Kuwada
Keyword(s):  
Growth Factor ◽  
Epithelial Cells ◽  
Tyrosine Phosphorylation ◽  
Basolateral Membrane ◽  
Growth Factor Receptor ◽  
Membrane Receptor ◽  
Membrane Receptors ◽  
Receptor Interaction ◽  
Signaling Proteins ◽  
Polarized Epithelial Cells

Signal transduction from receptors is mediated by the interaction of activated receptors with proximate downstream signaling proteins. In polarized epithelial cells, the membrane is divided into subdomains: the apical and basolateral membranes. Membrane receptors may be present in one or both subdomains. Using a combination of immunoprecipitation and Western blot analyses, we tested the hypothesis that a tyrosine kinase growth factor receptor, epidermal growth factor receptor (EGFR), interacts with distinct signaling proteins when present at the apical vs. basolateral membrane of a polarized renal epithelial cell. We report here that tyrosine phosphorylation of phospholipase C-γ (PLC-γ) was induced only when basolateral EGFR was activated. In contrast, tyrosine phosphorylation of several other signaling proteins was increased by activation of receptor at either surface. All signaling proteins were distributed diffusely throughout the cytoplasm; however, PLC-γ protein also displayed a concentration at lateral cell borders. These results demonstrate that in polarized epithelial cells the array of signaling pathways initiated by activation of a membrane receptor is defined, at least in part, by the membrane location of the receptor.

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