The opioid growth factor, [Met⁵]‐enkephalin, inhibits DNA synthesis during recornification of mouse tail skin

Abstract

Opioid peptides serve as tonically active negative growth regulators in renewing and regenerating epithelia. To examine the involvement of opioids in renewal of the stratum corneum after tape stripping of tail skin, C57BL/6 J mice were given systemic injections of the potent opioid antagonist, naltrexone (NTX, 20 mg/kg i.p.) following injury. Blockade of opioid-receptor interaction by NTX for 4 h resulted in an elevation of 36-66% in basal cell DNA synthesis measured 24 h after injury. Injection of the endogenous opioid peptide, [Met5]-enkephalin (OGF, 10 mg/kg i.p.) 4 h before termination, suppressed radiolabelled thymidine incorporation in the basal cell layer by 37-46% at 24 h after wounding. The magnitude of the effects on DNA synthesis of OGF, but not NTX, depended on the timing of administration with respect to injury. OGF maximally depressed basal cell labelling (72%) when given 16 h after tape stripping. Concomitant administration of naloxone (10 mg/kg) with OGF blocked the inhibition of DNA synthesis; naloxone alone at the dosage utilized had no effect on cell labelling. Both OGF and its receptor, OGFr, were detected by immunocytochemistry in the basal and suprabasal cell layers, but not the cornified layer of tape stripped and uninjured tail skin. These results indicate: (a) a native opioid peptide and its receptor are expressed in epidermal cells of injured and uninjured mouse tail skin; (b) removal of the stratum corneum by tape stripping does not disrupt the function of the endogenous opioid growth system; (c) the proliferative response to wounding of the tail is tonically inhibited by the receptor-mediated action of an endogenous opioid peptide; and (d) DNA synthesis by basal cells can be elevated by disrupting opioid peptide receptor interactions.

T lymphocyte proliferation is suppressed by the opioid growth factor ([Met5]-enkephalin)–opioid growth factor receptor axis: Implication for the treatment of autoimmune diseases

“…Although OGF-OGFr has the same pharmacological properties of opioid peptides that interact with classical opioid receptors (e.g., blockade by naloxone and stereospecificity), OGFr has nucleotide and protein sequences that are entirely different from that of classical opioid receptors (Zagon et al 2002). OGF-OGFr interactions inhibit cell proliferation in a tonically active fashion, and rigorously maintain homeostasis of cellular renewal and restorative processes (e.g., wound healing) (Zagon et al 1997(Zagon et al , 1998Wilson et al 2000;Blebea et al 2000;McLaughlin et al 2005). The OGF-OGFr axis upregulates the cyclin dependent inhibitory kinase pathway, specifically p16 and p21 (Cheng et al 2007a(Cheng et al ,b, 2009a, and does not induce apoptosis or necrosis (Zagon and McLaughlin 2003), or differentiation .…”

B lymphocyte proliferation is suppressed by the opioid growth factor–opioid growth factor receptor axis: Implication for the treatment of autoimmune diseases

“…Although the OGF-OGFr system has the same pharmacological properties of opioid peptides that interact with classical opioid receptors (e.g., blockade by naloxone, stereospecificity), OGFr has nucleotide and protein sequences that are entirely different from that of classical opioid receptors (Zagon et al 2002). OGF-OGFr interactions inhibit cell proliferation in a tonically active fashion and rigorously maintain homeostasis of cellular renewal and restorative processes (e.g., wound healing) (Zagon et al 1997;Wilson et al 2000;Blebea et al 2000). The OGF-OGFr axis does not alter differentiation or migration ), or induce apoptosis or necrosis (Zagon and McLaughlin 2003), but rather upregulates the cyclin-dependent inhibitory kinase pathway, specifically p16 and p21 (Cheng et al 2009b(Cheng et al , 2007a.…”

The OGF–OGFr Axis Utilizes the p16INK4aand p21WAF1/CIP1Pathways to Restrict Normal Cell Proliferation

“…The action of the OGF-OGFr axis in normal and cancer cells is targeted to DNA synthesis McLaughlin, 1987, 1991;Isayama et al, 1991;Zagon et al, 1994Zagon et al, , 1995bZagon et al, , 2000aMcLaughlin, 1996;McLaughlin and Wu, 1998;McLaughlin et al, 1999;Wilson et al, 2000;Blebea et al, 2002). In squamous cell carcinoma of the head and neck, OGF activity has been shown to be dependent on one CKI, p16…”

“…Because OGF depresses DNA synthesis and subsequent cell/tissue growth in a wide variety of normal and developing cells in humans and animals, including ectodermal, mesodermal, and endodermal derivatives Hauser and Stiene-Martin, 1991;Isayama et al, 1991;Zagon and McLaughlin, 1991;Zagon et al, 1994Zagon et al, , 1995bZagon et al, , 1996aZagon et al, ,b, 1997Zagon et al, , 1999bMcLaughlin, 1996;Vertes et al, 1996;McLaughlin and Wu, 1998;Blebea et al, 2000Blebea et al, , 2002Wilson et al, 2000;Kornyei et al, 2003), the question arises as to the mechanism of peptide action on the cell cycle in these cells. The present investigation examined the specific target(s) in the cell cycle for the OGF-OGFr axis in cells derived from four normal human tissues: umbilical vein endothelial This article was published online ahead of print in MBC in Press (http://www.molbiolcell.org/cgi/doi/10.1091/mbc.E08 -07-0681) on October 15, 2008. cells (HUVECs), epidermal keratinocytes (NHEKs), dermal fibroblasts (NHDFs), and mesenchymal stem cells (hMSCs).…”

“…OGF is a constitutively expressed native opioid that is autocrine produced and secreted to inhibit the growth of both normal cells McLaughlin, 1987, 1991;Hauser et al, 1990;Stiene-Martin and Hauser, 1990;Hauser and Stiene-Martin, 1991;Isayama et al, 1991;Villiger and Lotz, 1992;Zagon et al, 1994Zagon et al, , 1995aZagon et al, ,b, 1996aZagon et al, , 1997aZagon et al, ,b, 1998Zagon et al, , 1999bZagon et al, , 2000bMcLaughlin, 1996;Vertes et al, 1996;McLaughlin and Wu, 1998;Blebea et al, 2000;Wilson et al, 2000;Kornyei et al, 2003;Robertson and Andrew, 2003;Malendowicz et al, 2005) and cancer cells (Zagon et al, 1996c;Cheng et al, 2007Cheng et al, , 2008. The action of OGF is tonic, stereospecific, reversible, noncytotoxic, and nonapoptotic inducing, is not associated with differentiative, migratory, invasive, or adhesive processes, is independent of serum, anchorage-independent and occurs at physiologically relevant concentrations (Zagon et al, , 2007a, 2004.…”