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Cannabinoid receptor 1 but not 2 mediates macrophage phagocytosis by G(α)i/o /RhoA/ROCK signaling pathway.
J Cell Physiol. 2015 Jul; 230(7):1640-50.JC

Abstract

Phagocytosis is critical to macrophages linking innate and adaptive immune reaction. Cannabinoid receptor 1 (CB1) and 2 (CB2) mediate immune modulation. However, the role of cannabinoid receptors in macrophage phagocytosis is undefined. In this study, we found that two murine macrophage lines (J774A.1 and RAW264.7) and peripheral blood macrophages all expressed CB1 and CB2 by immunofluorescence-staining, real time RT-PCR and Western blot. Macrophage phagocytic activity was determined by quantifying fluorescent intensity of the engulfed BioParticles or fluorescence-activated cell sorting. mAEA (CB1 agonist) enhanced phagocytosis of macrophages, but JWH133 (CB2 agonist) had no influence. Pharmacological or genetic ablation of CB1 inhibited mAEA-enhanced phagocytosis, while CB2 had no such effects. Meanwhile, activation of CB1 increased GTP-bounding active form of small GTPase RhoA, but not Rac1 or Cdc42. AM281 (CB1 antagonist) and pertussis toxin (PTX, G((α)i/o) protein inhibitor) decreased GTP-bound RhoA protein level with mAEA. In addition, PTX, C3 Transferase (RhoA inhibitor) or Y27632 (Rho-associated kinase ROCK inhibitor) attenuated CB1-mediated phagocytosis. These results confirm that activation of CB1 regulates macrophage phagocytosis through G((α)i/o)/RhoA/ROCK signaling pathway. Moreover, activation of CB1 induced significant up-regulation of CB1 expression by real time RT-PCR and Western blot analysis, but not CB2. It indicated the existence of a positive feedback between CB1 activation and CB1 expression. The up-regulation of CB1 was RhoA-independent but it may contribute to maintaining high phagocytic activity of macrophages for a longer time. In conclusion, CB1 mediates macrophage phagocytosis by G((α)i/o)/RhoA/ROCK signal axis. These data further underline the role of CB1 in macrophage phagocytic process.

Authors+Show Affiliations

Department of Cell Biology, Municipal Laboratory for Liver Protection and Regulation of Regeneration, Capital Medical University, Beijing, China.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

25545473

Citation

Mai, Ping, et al. "Cannabinoid Receptor 1 but Not 2 Mediates Macrophage Phagocytosis By G(α)i/o /RhoA/ROCK Signaling Pathway." Journal of Cellular Physiology, vol. 230, no. 7, 2015, pp. 1640-50.
Mai P, Tian L, Yang L, et al. Cannabinoid receptor 1 but not 2 mediates macrophage phagocytosis by G(α)i/o /RhoA/ROCK signaling pathway. J Cell Physiol. 2015;230(7):1640-50.
Mai, P., Tian, L., Yang, L., Wang, L., Yang, L., & Li, L. (2015). Cannabinoid receptor 1 but not 2 mediates macrophage phagocytosis by G(α)i/o /RhoA/ROCK signaling pathway. Journal of Cellular Physiology, 230(7), 1640-50. https://doi.org/10.1002/jcp.24911
Mai P, et al. Cannabinoid Receptor 1 but Not 2 Mediates Macrophage Phagocytosis By G(α)i/o /RhoA/ROCK Signaling Pathway. J Cell Physiol. 2015;230(7):1640-50. PubMed PMID: 25545473.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Cannabinoid receptor 1 but not 2 mediates macrophage phagocytosis by G(α)i/o /RhoA/ROCK signaling pathway. AU - Mai,Ping, AU - Tian,Lei, AU - Yang,Le, AU - Wang,Lin, AU - Yang,Lin, AU - Li,Liying, PY - 2014/04/16/received PY - 2014/12/18/accepted PY - 2014/12/30/entrez PY - 2014/12/30/pubmed PY - 2015/6/3/medline SP - 1640 EP - 50 JF - Journal of cellular physiology JO - J Cell Physiol VL - 230 IS - 7 N2 - Phagocytosis is critical to macrophages linking innate and adaptive immune reaction. Cannabinoid receptor 1 (CB1) and 2 (CB2) mediate immune modulation. However, the role of cannabinoid receptors in macrophage phagocytosis is undefined. In this study, we found that two murine macrophage lines (J774A.1 and RAW264.7) and peripheral blood macrophages all expressed CB1 and CB2 by immunofluorescence-staining, real time RT-PCR and Western blot. Macrophage phagocytic activity was determined by quantifying fluorescent intensity of the engulfed BioParticles or fluorescence-activated cell sorting. mAEA (CB1 agonist) enhanced phagocytosis of macrophages, but JWH133 (CB2 agonist) had no influence. Pharmacological or genetic ablation of CB1 inhibited mAEA-enhanced phagocytosis, while CB2 had no such effects. Meanwhile, activation of CB1 increased GTP-bounding active form of small GTPase RhoA, but not Rac1 or Cdc42. AM281 (CB1 antagonist) and pertussis toxin (PTX, G((α)i/o) protein inhibitor) decreased GTP-bound RhoA protein level with mAEA. In addition, PTX, C3 Transferase (RhoA inhibitor) or Y27632 (Rho-associated kinase ROCK inhibitor) attenuated CB1-mediated phagocytosis. These results confirm that activation of CB1 regulates macrophage phagocytosis through G((α)i/o)/RhoA/ROCK signaling pathway. Moreover, activation of CB1 induced significant up-regulation of CB1 expression by real time RT-PCR and Western blot analysis, but not CB2. It indicated the existence of a positive feedback between CB1 activation and CB1 expression. The up-regulation of CB1 was RhoA-independent but it may contribute to maintaining high phagocytic activity of macrophages for a longer time. In conclusion, CB1 mediates macrophage phagocytosis by G((α)i/o)/RhoA/ROCK signal axis. These data further underline the role of CB1 in macrophage phagocytic process. SN - 1097-4652 UR - https://www.unboundmedicine.com/medline/citation/25545473/Cannabinoid_receptor_1_but_not_2_mediates_macrophage_phagocytosis_by_G_α_i/o_/RhoA/ROCK_signaling_pathway_ L2 - https://doi.org/10.1002/jcp.24911 DB - PRIME DP - Unbound Medicine ER -