Mochimaru Hiroshi, Takahashi Eri, Tsukamoto Nobuo, Miyazaki Junichiro, Yaguchi Tomonori, Koto Takashi, Kurihara Toshihide, Noda Kousuke, Ozawa Yoko, Ishimoto Takatsugu, Kawakami Yutaka, Tanihara Hidenobu, Saya Hideyuki, Ishida Susumu, Tsubota Kazuo
Department of Ophthalmology, Laboratory of Retinal Cell Biology, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo, Japan.
Invest Ophthalmol Vis Sci. 2009 Sep;50(9):4410-5. doi: 10.1167/iovs.08-3044. Epub 2009 Apr 1.
CD44 is a cell-surface adhesion molecule and receptor for hyaluronan (HA), one of the major extracellular matrix components. The purpose of the present study was to clarify a role of HA and CD44 in the development of choroidal neovascularization (CNV).
Laser photocoagulation was used to induce CNV in C57BL/6 mice or CD44-deficient mice. The mRNA expression of CD44 and HA synthase (HAS)-2 in the retinal pigment epithelium (RPE)-choroid complex was evaluated by DNA microarray and real-time RT-PCR analyses 3 days after laser treatment. HA synthesis and CD44 expression were examined by immunohistochemistry 1 week after photocoagulation. Mice with laser-induced CNV were systemically administered the HA synthesis inhibitor 4-methylumbelliferone (MU) or an anti-CD44-neutralizing antibody. The response of CNV was analyzed by volumetric measurements 1 week after photocoagulation. Macrophage infiltration into CNV lesions was evaluated by real-time RT-PCR for F4/80 3 days after laser-induced injury.
The induction of CNV led to a significant increase in expression of CD44 and HAS2 mRNA. HA and CD44 were immunopositive in the CNV lesions. Compared with vehicle treatment, the systemic application of MU significantly attenuated CNV volume in a dose-dependent fashion, together with macrophage infiltration into the lesions. Consistently, antibody-based blockade of CD44 resulted in a significant reduction of CNV volume, compared with the isotype control. In contrast, genetic ablation of CD44 significantly augmented CNV formation together with HA accumulation and macrophage infiltration, compared with wild-type mice.
These results indicate a significant role of HA and its receptor CD44 in the development of CNV.
CD44是一种细胞表面黏附分子，也是透明质酸（HA）的受体，HA是细胞外基质的主要成分之一。本研究旨在阐明HA和CD44在脉络膜新生血管（CNV）形成过程中的作用。
采用激光光凝诱导C57BL/6小鼠或CD44基因缺陷小鼠形成CNV。激光治疗3天后，通过DNA微阵列和实时逆转录-聚合酶链反应（RT-PCR）分析评估视网膜色素上皮（RPE）-脉络膜复合体中CD44和HA合酶（HAS）-2的mRNA表达。光凝1周后，通过免疫组织化学检测HA合成和CD44表达。对激光诱导CNV的小鼠全身给予HA合成抑制剂4-甲基伞形酮（MU）或抗CD44中和抗体。光凝1周后，通过体积测量分析CNV的反应。激光诱导损伤3天后，通过实时RT-PCR检测F4/80评估巨噬细胞向CNV病变的浸润情况。
CNV的诱导导致CD44和HAS2 mRNA表达显著增加。HA和CD44在CNV病变中呈免疫阳性。与载体治疗相比，全身应用MU以剂量依赖方式显著减轻CNV体积，同时减少巨噬细胞向病变的浸润。同样，与同型对照相比，基于抗体的CD44阻断导致CNV体积显著减少。相反，与野生型小鼠相比，CD44基因敲除显著增加CNV形成，同时伴有HA积累和巨噬细胞浸润。
这些结果表明HA及其受体CD44在CNV形成过程中起重要作用。
