title: Corticotropin-releasing hormone and urocortin promote phagocytosis of rat macrophages through convergent but distinct pathways.
abstract: OBJECTIVE
  Phagocytosis plays essential roles during inflammation and immune response. This study aims to explore the underlying mechanism of corticotropin-releasing hormone (CRH) and urocortin (UCN)-promoted phagocytosis of rat macrophages.
  
  
  METHODS
  To induce phagocytosis, rat macrophages were incubated with carboxylated fluorescent microspheres. The phagocytosis activity was evaluated by flow cytometric analysis. Actin reorganization was determined by immunostaining with TRITC-labeled phalloidin and transmission electron microscopy (TEM) analysis. Protein expressions of p-RhoA, p-Rac1, p-extracellular signal-related kinase (ERK)1/2 and GAPDH were examined by Western blotting. Protein kinase C (PKC) and protein kinase A (PKA) activities were examined using PreTag non-radio activity assay.
  
  
  RESULTS
  Administration of CRH or UCN alone significantly enhanced phagocytosis of microspheres by rat macrophages, as well as actin reorganization. Ligation of CRH and UCN with CRH receptor increased the phosphorylation of both RhoA and Rac1. Inhibition of RhoA/Rac1 signal pathway suppressed CRH- or UCN-enhanced phagocytosis and actin reorganization. Blockage of PKA signal by MDL-12330A decreased CRH or UCN-promoted p-RhoA and p-Rac1 expressions. Blockage of PKC signal by cholerythine choride decreased CRH or UCN-promoted p-Rac1 expression and UCN-promoted p-RhoA expression, but increased the CRH-induced p-RhoA expression. ERK1/2 was also activated and served as upstream factor of RhoA/Rac1 signal pathway.
  
  
  CONCLUSIONS
  The results reveal that CRH and UCN promote phagocytosis of rat macrophages through convergent but dissociable pathways. PKA/PKC-ERK1/2-RhoA/Rac1 signal pathway plays an essential role in CRH- and UCN-enhanced phagocytosis.
authors.affiliation: Anesthesiology, Research Institute of Surgery & Daping Hospital, Third Military Medical University, 10 Changjiangzhilu Rd, Daping, Chongqing 400042, China.
authors.forename: Wu-Chao
authors.initials: WC
authors.lastname: Wang
authors.affiliation: Institute for Traffic Medicine, Research Institute of Surgery & Daping Hospital, Third Military Medical University, 10 Changjiangzhilu Rd, Daping, Chongqing 400042, China.
authors.forename: Xiu-Zhu
authors.initials: XZ
authors.lastname: Zhang
authors.affiliation: Institute for Traffic Medicine, Research Institute of Surgery & Daping Hospital, Third Military Medical University, 10 Changjiangzhilu Rd, Daping, Chongqing 400042, China.
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Liu
authors.affiliation: Institute for Traffic Medicine, Research Institute of Surgery & Daping Hospital, Third Military Medical University, 10 Changjiangzhilu Rd, Daping, Chongqing 400042, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Institute for Traffic Medicine, Research Institute of Surgery & Daping Hospital, Third Military Medical University, 10 Changjiangzhilu Rd, Daping, Chongqing 400042, China.
authors.forename: Xu-Hui
authors.initials: XH
authors.lastname: Wang
authors.affiliation: Institute for Traffic Medicine, Research Institute of Surgery & Daping Hospital, Third Military Medical University, 10 Changjiangzhilu Rd, Daping, Chongqing 400042, China. Electronic address: 646664760@qq.com.
authors.forename: Ji-Hong
authors.initials: JH
authors.lastname: Zhou
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006728:Hormones / Q000494:pharmacology*; D007124:Immunoenzyme Techniques; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects*; D054832:Urocortins / Q000494:pharmacology*; D020830:rac1 GTP-Binding Protein / Q000378:metabolism; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D006728:Hormones; D054832:Urocortins; D003346:Corticotropin-Releasing Hormone; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020830:rac1 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein
keywords: Actin reorganization; CRH; Macrophages; Phagocytosis; UCN