Activation of α7nAChR Promotes Diabetic Wound Healing by Suppressing AGE-Induced TNF-α Production
- 638 Downloads
Diabetes frequently presents accumulation of advanced glycation end products (AGEs), which might induce excessive TNF-α production from macrophages to cause impaired wound healing. Recent studies have shown that activation of α7 nicotinic acetylcholine receptor (α7nAChR) on macrophages efficiently suppressed TNF-α synthesis. The aim of this study was to investigate the accumulation of AGEs in the wounds and determine whether PNU282987, an α7nAChR agonist, can improve wound repair by inhibiting AGE-mediated TNF-α production in a streptozotocin (STZ)-induced diabetic mouse model. Animals were assigned into four groups: wounded control group, wounded diabetic group, wounded diabetic group treated intraperitoneally with PNU282987, or wounded diabetic group treated intraperitoneally with vehicle. Compared with the non-diabetic control mice, the diabetic mice exhibited delayed wound healing that was characterized by elevated accumulation of AGEs, increased TNF-α level and macrophage infiltration, and decreased fibroblast number and collagen deposition at the late stage of repair. Besides, macrophages of diabetic wounds showed expression of α7nAChR. During late repair, PNU282987 treatment of diabetic mice significantly reduced the level of TNF-α, accelerated wound healing, and elevated fibroblast number and collagen deposition. To investigate the cellular mechanism of these observations, RAW 264.7 cells, a macrophage cell line, were incubated with AGEs in the presence or absence of PNU282987. TNF-α production from AGE-stimulated macrophages was significantly decreased by PNU282987 in a dose-dependent manner. Furthermore, PNU282987 significantly inhibited AGE-induced nuclear factor-κB (NF-κB) activation and receptor for AGE (RAGE) expression. These results strongly suggest that activating α7nAChR can promote diabetic wound healing by suppressing AGE-induced TNF-α production, which may be closely associated with the blockage of NF-κB activation in macrophages.
KEY WORDSdiabetes wound healing α7nAChR AGEs TNF-α macrophage
This study was financially supported by grants from research funds for the Zhejiang Provincial Natural Science Foundation of China (LQ13H150002) and the National Natural Science Foundation of China (81301640).
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no competing interests.
- 4.Wetzler, C., H. Kampfer, B. Stallmeyer, J. Pfeilschifter, and S. Frank. 2000. Large and sustained induction of chemokines during impaired wound healing in the genetically diabetic mouse prolonged persistence of neutrophils and macrophages during the late phase of repair. Journal of Investigative Dermatology 115: 245–253.CrossRefPubMedGoogle Scholar
- 6.Ebaid, H., O.M. Ahmed, A.M. Mahmoud, and R.R. Ahmed. 2013. Limiting prolonged inflammation during proliferation and remodeling phases of wound healing in streptozotocin-induced diabetic rats supplemented with camel undenatured whey protein. BMC Immunology 14: 31.CrossRefPubMedPubMedCentralGoogle Scholar
- 13.Takahashi, H.K., S. Mori, H. Wake, et al. 2009. Advanced glycation end products subspecies-selectively induce adhesion molecule expression and cytokine production in human peripheral blood mononuclear cells. Journal of Pharmacology and Experimental Therapeutics 330: 89–98.CrossRefPubMedGoogle Scholar
- 14.Qin, Q., J. Niu, Z. Wang, et al. 2012. Astragalus membranaceus inhibits inflammation via phospho-P38 mitogen-activated protein kinase (MAPK) and nuclear factor (NF)-κB pathways in advanced glycation end product-stimulated macrophages. International Journal of Molecular Sciences 13: 8379–8387.CrossRefPubMedPubMedCentralGoogle Scholar
- 22.de Jonge, W.J., E.P. van der Zanden, The FO, M.F. Bijlsma, D.J. van Westerloo, R.J. Bennink, H.R. Berthoud, S. Uematsu, S. Akira, R.M. van den Wijngaard, and G.E. Boeckxstaens. 2005. Stimulation of the vagus nerve attenuates macrophage activation by activating the Jak2-STAT3 signaling pathway. Nature Immunology 6: 844–851.CrossRefPubMedGoogle Scholar
- 28.Liu, L.P., T.H. Yan, L.Y. Jiang, W. Hu, M. Hu, C. Wang, Q. Zhang, Y. Long, J.Q. Wang, Y.Q. Li, M. Hu, and H. Hong. 2013. Pioglitazone ameliorates memory deficits in streptozotocin-induced diabetic mice by reducing brain β-amyloid through PPARγ activation. Acta Pharmacologica Sinica 34: 455–463.CrossRefPubMedPubMedCentralGoogle Scholar
- 31.Shelukhina, I.V., E.V. Kryukova, K.S. Lips, V.I. Tsetlin, and W. Kummer. 2009. Presence of alpha7 nicotinic acetylcholine receptors on dorsal root ganglion neurons proved using knockout mice and selective alpha-neurotoxins in histochemistry. Journal of Neurochemistry 109: 1087–1095.CrossRefPubMedGoogle Scholar
- 40.Ashcroft, G.S., M.J. Jeong, J.J. Ashworth, M. Hardman, W. Jin, N. Moutsopoulos, T. Wild, N. McCartney-Francis, D. Sim, G. McGrady, X.Y. Song, and S.M. Wahl. 2012. Tumor necrosis factor-alpha (TNF-α) is a therapeutic target for impaired cutaneous wound healing. Wound Repair and Regeneration 20: 38–49.CrossRefPubMedPubMedCentralGoogle Scholar
- 44.Moser, N., N. Mechawar, I. Jones, A. Gochberg-Sarver, A. Orr-Urtreger, M. Plomann, R. Salas, B. Molles, L. Marubio, U. Roth, U. Maskos, U. Winzer-Serhan, J.P. Bourgeois, A.M. Le Sourd, M. De Biasi, H. Schroder, J. Lindstrom, A. Maelicke, J.P. Changeux, and A. Wevers. 2007. Evaluating the suitability of nicotinic acetylcholine receptor antibodies for standard immunodetection procedures. Journal of Neurochemistry 102: 479–492.CrossRefPubMedGoogle Scholar
- 45.Rommel, F.R., B. Raghavan, R. Paddenberg, W. Kummer, S. Tumala, G. Lochnit, U. Gieler, and E.M. Peters. 2015. Suitability of nicotinic acetylcholine receptor α7 and muscarinic acetylcholine receptor 3 antibodies for immune detection: evaluation in murine skin. Journal of Histochemistry and Cytochemistry 63: 329–339.CrossRefPubMedGoogle Scholar
- 49.Khan, M.A., M. Farkhondeh, J. Crombie, L. Jacobson, M. Kaneki, and J.A. Martyn. 2012. Lipopolysaccharide upregulates α7 acetylcholine receptors: stimulation with GTS-21 mitigates growth arrest of macrophages and improves survival in burned mice. Shock 38: 213–219.CrossRefPubMedPubMedCentralGoogle Scholar
- 51.Parrish, W.R., M. Rosas-Ballina, M. Gallowitsch-Puerta, M. Ochani, K. Ochani, L.H. Yang, L. Hudson, X. Lin, N. Patel, S.M. Johnson, S. Chavan, R.S. Goldstein, C.J. Czura, E.J. Miller, Y. Al-Abed, K.J. Tracey, and V.A. Pavlov. 2008. Modulation of TNF release by choline requires alpha7 subunit nicotinic acetylcholine receptor-mediated signaling. Molecular Medicine 14: 567–574.CrossRefPubMedPubMedCentralGoogle Scholar
- 52.Sitapara, R.A., D.J. Antoine, L. Sharma, V.S. Patel, C.R. Ashby Jr., S. Gorasiya, H. Yang, M. Zur, and L.L. Mantell. 2014. The α7 nicotinic acetylcholine receptor agonist GTS-21 improves bacterial clearance in mice by restoring hyperoxia-compromised macrophage function. Molecular Medicine 20: 238–247.CrossRefPubMedPubMedCentralGoogle Scholar
- 54.Leite, P.E., L. Gandía, R. de Pascual, C. Nanclares, I. Colmena, W.C. Santos, J. Lagrota-Candido, and T. Quirico-Santos. 2014. Selective activation of α7 nicotinic acetylcholine receptor (nAChRα7) inhibits muscular degeneration in mdx dystrophic mice. Brain Research 1573: 27–36.CrossRefPubMedGoogle Scholar