<p>Spontaneous experimental autoimmune uveoretinitis (EAU) in double-transgenic (dTg) mice expressing retinal Hen Egg Lysozyme (HEL) and HEL-specific T cell receptor CD4 T cells is a severe CD4⁺ T cell-driven disease, occurs in 100% of dTg mice at post-partum day (p)20/21 and is accompanied by post-EAU colitis. Because DOCK2 (Dedicator of cytokinesis 2) is essential for Rac-dependent immune cell function, including T cell motility and migration from secondary lymphoid tissues, we investigated its effect on T cell behaviour in this model. dTg mice lacking DOCK2 (DOCK2<sup>⁻/⁻</sup> dTg) were examined for evidence of uveitis (fundoscopy, histology and flow cytometry) and intestinal inflammation (colon length and histology). Retinal inflammation and ocular CD4⁺ T cell infiltration were assessed over time. Flow cytometry of lamina propria cells quantified CD4⁺ T cells and determined the balance of Helios<sup>+</sup> versus Helios<sup>−</sup> regulatory T cells. The eye-draining lymph nodes were also analysed for CD4⁺ T cell populations. DOCK2<sup>⁻/⁻</sup> dTg mice showed delayed and attenuated uveitis. Retinal inflammation, consistently evident by p21 in DOCK2<sup>+/+</sup> dTg mice, and atrophy (~ p30) were absent until ~p60 and were associated with markedly reduced ocular CD4⁺ T cell infiltration. Despite profound lymphopenia, DOCK2 deficiency did not induce spontaneous colitis; colons were normal in length and lacked inflammation. Flow cytometry of lamina propria cells showed no change in overall CD4⁺ T cell numbers between DOCK2<sup>⁻/⁻</sup> and DOCK2<sup>⁺/⁺</sup> mice. However, the balance of Helios expression in Treg was altered, with DOCK2<sup>⁻/⁻</sup> mice containing significantly higher numbers of Helios<sup>−</sup> Treg in the lamina propria compared to DOCK2<sup>+/+</sup> mice. In contrast, peripheral lymphoid tissues (eye-draining lymph nodes), showed disproportionately reduced CD4⁺ T cell numbers in DOCK2<sup>⁻/⁻</sup> dTg mice. We conclude DOCK2 may be a potential target for control of uveoretinitis <i>via</i> expansion of eye-homing gut Helios<sup>−</sup> Treg.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Deficiency of DOCK2 delays development of spontaneous uveoretinitis in a lymphopenic mouse model of colitis

  • Christine Mölzer,
  • Izabela P. Klaska,
  • Tian Yu,
  • Rosie Fordyce,
  • Elizabeth Muckersie,
  • Yoshinori Fukui,
  • John V. Forrester,
  • Lucia Kuffova

摘要

Spontaneous experimental autoimmune uveoretinitis (EAU) in double-transgenic (dTg) mice expressing retinal Hen Egg Lysozyme (HEL) and HEL-specific T cell receptor CD4 T cells is a severe CD4⁺ T cell-driven disease, occurs in 100% of dTg mice at post-partum day (p)20/21 and is accompanied by post-EAU colitis. Because DOCK2 (Dedicator of cytokinesis 2) is essential for Rac-dependent immune cell function, including T cell motility and migration from secondary lymphoid tissues, we investigated its effect on T cell behaviour in this model. dTg mice lacking DOCK2 (DOCK2⁻/⁻ dTg) were examined for evidence of uveitis (fundoscopy, histology and flow cytometry) and intestinal inflammation (colon length and histology). Retinal inflammation and ocular CD4⁺ T cell infiltration were assessed over time. Flow cytometry of lamina propria cells quantified CD4⁺ T cells and determined the balance of Helios+ versus Helios regulatory T cells. The eye-draining lymph nodes were also analysed for CD4⁺ T cell populations. DOCK2⁻/⁻ dTg mice showed delayed and attenuated uveitis. Retinal inflammation, consistently evident by p21 in DOCK2+/+ dTg mice, and atrophy (~ p30) were absent until ~p60 and were associated with markedly reduced ocular CD4⁺ T cell infiltration. Despite profound lymphopenia, DOCK2 deficiency did not induce spontaneous colitis; colons were normal in length and lacked inflammation. Flow cytometry of lamina propria cells showed no change in overall CD4⁺ T cell numbers between DOCK2⁻/⁻ and DOCK2⁺/⁺ mice. However, the balance of Helios expression in Treg was altered, with DOCK2⁻/⁻ mice containing significantly higher numbers of Helios Treg in the lamina propria compared to DOCK2+/+ mice. In contrast, peripheral lymphoid tissues (eye-draining lymph nodes), showed disproportionately reduced CD4⁺ T cell numbers in DOCK2⁻/⁻ dTg mice. We conclude DOCK2 may be a potential target for control of uveoretinitis via expansion of eye-homing gut Helios Treg.