Akemi Suzuki

Publications (2)16.25 Total impact

• Article: Heterogeneity of gangliosides among T cell subsets.

  Jin-Ichi Inokuchi, Masakazu Nagafuku, Isao Ohno, Akemi Suzuki
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  ABSTRACT: Gangliosides are major components of highly organized membrane microdomains or rafts, yet little is known about the role of gangliosides in raft organization. This is also the case of gangliosides in TCR-mediated activation. Comprehensive structural analysis of gangliosides in the primary thymocytes and CD4(+) T and CD8(+) T cells was not achieved due to technical difficulties. We have found that CD8(+) T cells express very high levels of o-series gangliosides, but on the other hand, CD4(+) T cells preferably express a-series gangliosides. In the TCR-dependent activation, CD4(+) T cells selectively require a-series gangliosides, but CD8(+) T cells do require only o-series gangliosides but not a-series gangliosides. Ganglioside GM3 synthase-deficient mice lacking a-series gangliosides neither exhibited the TCR-dependent activation of CD4(+) T nor developed ovalbumin-induced allergic airway inflammation. These findings imply that the distinct expression pattern of ganglioside species in CD4(+) and CD8(+) T cells define the immune function of each T cell subset.
  Cellular and Molecular Life Sciences CMLS 12/2012; · 6.57 Impact Factor
• Article: CD4 and CD8 T cells require different membrane gangliosides for activation.

  Masakazu Nagafuku, Kaori Okuyama, Yuri Onimaru, Akemi Suzuki, Yuta Odagiri, Tadashi Yamashita, Katsunori Iwasaki, Michihiro Fujiwara, Motoaki Takayanagi, Isao Ohno, Jin-ichi Inokuchi
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  ABSTRACT: Initial events of T-cell activation involve movement of the T-cell receptor into lipid rafts. Gangliosides are major components of lipid rafts. While investigating T-cell activation in ganglioside-deficient mice, we observed that CD4(+) and CD8(+) T cells required different ganglioside subsets for activation. Activation of CD4(+) T cells from GM3 synthase-null mice, deficient in GM3-derived gangliosides, is severely compromised, whereas CD8(+) T-cell activation is normal. Conversely, in cells from GM2/GD2 synthase-null mice, expressing only GM3 and GD3, CD4(+) T-cell activation is normal, whereas CD8(+) T-cell activation is deficient. Supplementing the cells with the corresponding missing gangliosides restores normal activation. GM3 synthase-null mice do not develop experimental asthma. Distinct expression patterns of ganglioside species in CD4(+) T and CD8(+) T cells, perhaps in uniquely functional lipid rafts, define immune functions in each T-cell subset. Control of ganglioside expression would offer a strategy targeting for specific T-cell subpopulations to treat immune diseases.
  Proceedings of the National Academy of Sciences 02/2012; 109(6):E336-42. · 9.68 Impact Factor