Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, Oregon, United States.
Invest Ophthalmol Vis Sci. 2023 Jul 3;64(10):6. doi: 10.1167/iovs.64.10.6.
TGFβ-induced epithelial-to-myofibroblast transition (EMyT) of lens cells has been linked to the most common vision-disrupting complication of cataract surgery-namely, posterior capsule opacification (PCO; secondary cataract). Although inhibitors of the ErbB family of receptor tyrosine kinases have been shown to block some PCO-associated processes in model systems, our knowledge of ErbB signaling in the lens is very limited. Here, we investigate the expression of ErbBs and their ligands in primary cultures of chick lens epithelial cells (dissociated cell-derived monolayer cultures [DCDMLs]) and how TGFβ affects ErbB function.
DCDMLs were analyzed by immunofluorescence microscopy and Western blotting under basal and profibrotic conditions.
Small-molecule ErbB kinase blockers, including the human therapeutic lapatinib, selectively inhibit TGFβ-induced EMyT of DCDMLs. Lens cells constitutively express ErbB1 (EGFR), ErbB2, and ErbB4 protein on the plasma membrane and release into the medium ErbB-activating ligand. Culturing DCDMLs with TGFβ increases soluble bioactive ErbB ligand and markedly alters ErbBs, reducing total and cell surface ErbB2 and ErbB4 while increasing ErbB1 expression and homodimer formation. Similar, TGFβ-dependent changes in relative ErbB expression are induced when lens cells are exposed to the profibrotic substrate fibronectin. A single, 1-hour treatment with lapatinib inhibits EMyT in DCDMLs assessed 6 days later. Short-term exposure to lower doses of lapatinib is also capable of eliciting a durable response when combined with suboptimal levels of a mechanistically distinct multikinase inhibitor.
Our findings support ErbB1 as a therapeutic target for fibrotic PCO, which could be leveraged to pharmaceutically preserve the vision of millions of patients with cataracts.
转化生长因子β（TGFβ）诱导晶状体细胞上皮-间充质转化（EMyT）与白内障手术后最常见的视力障碍并发症有关，即后囊混浊（PCO；继发性白内障）。尽管已经表明，表皮生长因子受体（ErbB）家族受体酪氨酸激酶抑制剂可以阻断模型系统中某些与 PCO 相关的过程，但我们对晶状体中 ErbB 信号的了解非常有限。在这里，我们研究了 ErbB 及其配体在鸡晶状体上皮细胞原代培养物（分离细胞衍生的单层培养物[DCDMLs]）中的表达情况，以及 TGFβ 如何影响 ErbB 功能。
在基础和促纤维化条件下，通过免疫荧光显微镜和 Western blot 分析 DCDMLs。
小分子 ErbB 激酶抑制剂，包括人治疗性拉帕替尼，选择性抑制 DCDMLs 中 TGFβ 诱导的 EMyT。晶状体细胞在质膜上持续表达 ErbB1（EGFR）、ErbB2 和 ErbB4 蛋白，并将激活 ErbB 的配体释放到培养基中。用 TGFβ 培养 DCDMLs 会增加可溶性生物活性 ErbB 配体，并显著改变 ErbBs，减少总和细胞表面 ErbB2 和 ErbB4，同时增加 ErbB1 的表达和同源二聚体形成。当晶状体细胞暴露于促纤维化底物纤维连接蛋白时，会诱导类似的、依赖于 TGFβ 的相对 ErbB 表达变化。用拉帕替尼进行单次 1 小时处理可抑制 6 天后 DCDMLs 中的 EMyT。当与机制上不同的多激酶抑制剂的非最佳水平联合使用时，短期暴露于较低剂量的拉帕替尼也能够引发持久反应。
我们的研究结果支持将 ErbB1 作为纤维化 PCO 的治疗靶点，这可能会被用于通过药物手段来保护数百万白内障患者的视力。
