Open Access

Fc gamma receptor IIb participates in maternal IgG trafficking of human placental endothelial cells

  • Authors:
    • Tomoko Ishikawa
    • Takami Takizawa
    • Jun Iwaki
    • Takuya Mishima
    • Kumiko Ui-Tei
    • Toshiyuki Takeshita
    • Shigeki Matsubara
    • Toshihiro Takizawa
  • View Affiliations

  • Published online on: March 17, 2015     https://doi.org/10.3892/ijmm.2015.2141
  • Pages: 1273-1289
  • Copyright: © Ishikawa et al. This is an open access article distributed under the terms of Creative Commons Attribution License [CC BY_NC 3.0].

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Abstract

The human placental transfer of maternal IgG is crucial for fetal and newborn immunity. Low-affinity immunoglobulin gamma Fc region receptor IIb2 (FCGR2B2 or FcγRIIb2) is exclusively expressed in an IgG-containing, vesicle-like organelle (the FCGR2B2 compartment) in human placental endothelial cells; thus, we hypothesized that the FCGR2B2 compartment functions as an IgG transporter. In this study, to examine this hypothesis, we performed in vitro bio-imaging analysis of IgG trafficking by FCGR2B2 compartments using human umbilical vein endothelial cells transfected with a plasmid vector containing enhanced GFP-tagged FCGR2B2 (pFCGR2B2-EGFP). FCGR2B2-EGFP signals were detected as intracellular vesicular structures similar to FCGR2B2 compartments in vivo. The internalization and transcytosis of IgG was significantly higher in the pFCGR2B2-EGFP-transfected cells than in the mock-transfected cells, and the majority of the internalized IgG was co-localized with the FCGR2B2-EGFP signals. Furthermore, we isolated FCGR2B2 compartments from the human placenta and found that the Rab family of proteins [RAS-related protein Rab family (RABs)] were associated with FCGR2B2 compartments. Among the RABs, RAB3D was expressed predominantly in placental endothelial cells. The downregulation of RAB3D by small interfering RNA (siRNA) resulted in a marked reduction in the FCGR2B2-EGFP signals at the cell periphery. Taken together, these findings suggest that FCGR2B2 compartments participate in the transcytosis of maternal IgG across the human placental endothelium and that RAB3D plays a role in regulating the intracellular dynamics of FCGR2B2 compartments.
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May-2015
Volume 35 Issue 5

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Ishikawa T, Takizawa T, Iwaki J, Mishima T, Ui-Tei K, Takeshita T, Matsubara S and Takizawa T: Fc gamma receptor IIb participates in maternal IgG trafficking of human placental endothelial cells. Int J Mol Med 35: 1273-1289, 2015.
APA
Ishikawa, T., Takizawa, T., Iwaki, J., Mishima, T., Ui-Tei, K., Takeshita, T. ... Takizawa, T. (2015). Fc gamma receptor IIb participates in maternal IgG trafficking of human placental endothelial cells. International Journal of Molecular Medicine, 35, 1273-1289. https://doi.org/10.3892/ijmm.2015.2141
MLA
Ishikawa, T., Takizawa, T., Iwaki, J., Mishima, T., Ui-Tei, K., Takeshita, T., Matsubara, S., Takizawa, T."Fc gamma receptor IIb participates in maternal IgG trafficking of human placental endothelial cells". International Journal of Molecular Medicine 35.5 (2015): 1273-1289.
Chicago
Ishikawa, T., Takizawa, T., Iwaki, J., Mishima, T., Ui-Tei, K., Takeshita, T., Matsubara, S., Takizawa, T."Fc gamma receptor IIb participates in maternal IgG trafficking of human placental endothelial cells". International Journal of Molecular Medicine 35, no. 5 (2015): 1273-1289. https://doi.org/10.3892/ijmm.2015.2141