State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China.
Yale College, Yale University, New Haven, Connecticut, United States.
Invest Ophthalmol Vis Sci. 2024 Jun 3;65(6):34. doi: 10.1167/iovs.65.6.34.
The aim of this study was to elucidate the role of Sema4D in the pathogenesis of senescence-associated choroidal neovascularization (CNV) and to explore its underlying mechanisms.
In this study, we utilized a model of laser-induced CNV in both young (3 months old) and old (18 months old) mice, including those with or without Sema4D knockout. The expression and localization of Sema4D in CNV were assessed using PCR, Western blot, and immunostaining. Subsequently, the morphological and imaging examinations were used to evaluate the size of CNV and vascular leakage. Finally, the expression of M2 markers, senescence-related markers, and molecules involved in the RhoA/ROCK pathway was detected.
We found that Sema4D was predominantly expressed in macrophages within CNV lesions, and both the mRNA and protein levels of Sema4D progressively increased following laser photocoagulation, a trend more pronounced in old mice. Moreover, Sema4D knockout markedly inhibited M2 polarization in senescent macrophages and reduced the size and leakage of CNV, particularly in aged mice. Mechanistically, aging was found to upregulate RhoA/ROCK signaling, and knockout of Sema4D effectively suppressed the activation of this pathway, with more significant effects observed in aged mice.
Our findings revealed that the deletion of Sema4D markedly inhibited M2 macrophage polarization through the suppression of the RhoA/ROCK pathway, ultimately leading to the attenuation of senescence-associated CNV. These data indicate that targeting Sema4D could offer a promising approach for gene editing therapy in patients with neovascular age-related macular degeneration.
本研究旨在阐明 Sema4D 在衰老相关性脉络膜新生血管（CNV）发病机制中的作用，并探讨其潜在机制。
本研究利用年轻（3 个月大）和老年（18 个月大）小鼠的激光诱导 CNV 模型，包括 Sema4D 敲除或不敲除的小鼠。采用 PCR、Western blot 和免疫染色检测 Sema4D 在 CNV 中的表达和定位。随后，采用形态学和成像检查评估 CNV 大小和血管渗漏。最后，检测 M2 标志物、衰老相关标志物和 RhoA/ROCK 通路相关分子的表达。
我们发现 Sema4D 主要在 CNV 病变中的巨噬细胞中表达，并且 Sema4D 的 mRNA 和蛋白水平在激光光凝后逐渐增加，在老年小鼠中更为明显。此外，Sema4D 敲除显著抑制衰老巨噬细胞的 M2 极化，并减少 CNV 的大小和渗漏，在老年小鼠中更为显著。机制上，衰老导致 RhoA/ROCK 信号通路的上调，Sema4D 敲除有效抑制该通路的激活，在老年小鼠中效果更为明显。
我们的研究结果表明，Sema4D 的缺失通过抑制 RhoA/ROCK 通路显著抑制 M2 巨噬细胞极化，最终导致衰老相关性 CNV 的减弱。这些数据表明，针对 Sema4D 可能为治疗与年龄相关的新生血管性黄斑变性的基因编辑治疗提供一种有前途的方法。
