Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, China.
College of Food Science and Engineering, Ocean University of China, Qingdao, China.
Acta Biomater. 2023 Oct 1;169:398-409. doi: 10.1016/j.actbio.2023.08.019. Epub 2023 Aug 12.
Fungal keratitis (FK) is a severe infectious corneal disease. Since traditional eye drops exhibit poor dissolution and high corneal toxicity, the efficacy of current treatments for FK remains limited. It is needed to develop new approaches to control the cornea damage from FK. In this study, a nanobody (Nb) specific to β-glucan in the fungal cell wall was prepared. The conjugate of the Nb with natamycin (NAT), a traditional antifungal drug, was synthesized. Firstly, we found the Nb specific to β-glucan inhibited fungal growth by disrupting cell wall and biofilm formation.. In addition, the content of β-glucan in the fungal cell wall decreased after Nb treatment. The Nb also reduced the adhesion ability of fungal conidia to human corneal epithelial cells (HCECs). Further, we examined the difference between NAT and Nb-NAT in antifungal growth. Nb-NAT showed better antifungal effects than NAT which was caused by the interaction between Nb and β-glucan. Moreover, Nb concentration below 0.5 mg/mL did not affect the viability of HCECs. Nb-NAT had less cytotoxicity and ocular surface irritation than NAT. Nb specific to β-glucan attenuated Aspergillus fumigatus (A. fumigatus) virulence and relieved inflammatory responses in FK. Nb-NAT treatment of the cornea improved therapeutic effects compared with NAT. It decreased clinical scores and expression level of inflammatory factors. To our knowledge, this study is the first to report a Nb specific to β-glucan and Nb-NAT for the treatment of FK. These unique functions of the Nb specific to β-glucan and Nb-NAT would render it as an alternative molecule to control fungal infections including FK. STATEMENT OF SIGNIFICANCE: Fungal keratitis is a corneal disease with a high rate of blindness. Due to the poor dissolution and high corneal toxicity exhibited by traditional eye drops, the efficacy of current therapeutic treatments for fungal keratitis (FK) remains limited. To enhance the therapeutic effect of natamycin in treating fungal keratitis, this study developed an innovative approach by preparing a β-glucan-specific nanobody and loading it with the antifungal drug natamycin. The β-glucan-specific nanobody has the ability to control both fungal pathogen invasion and inflammation, which can cause damage to the cornea in FK. The conjugation with the β-glucan-specific nanobody significantly increased the antifungal capacity of natamycin and reduced its toxicity. The further application of natamycin conjugated with the β-glucan-specific nanobody could be expanded to other diseases caused by fungal pathogen infections.
真菌性角膜炎（FK）是一种严重的传染性角膜疾病。由于传统眼药水溶解度差、角膜毒性高，目前 FK 的治疗效果仍然有限。需要开发新的方法来控制 FK 引起的角膜损伤。在这项研究中，制备了一种针对真菌细胞壁中β-葡聚糖的纳米抗体（Nb）。合成了 Nb 与传统抗真菌药物那他霉素（NAT）的缀合物。首先，我们发现针对β-葡聚糖的 Nb 通过破坏细胞壁和生物膜形成来抑制真菌生长。此外，Nb 处理后真菌细胞壁中的β-葡聚糖含量降低。Nb 还降低了真菌分生孢子与人类角膜上皮细胞（HCEC）的粘附能力。进一步研究了 NAT 和 Nb-NAT 在抗真菌生长方面的差异。由于 Nb 与β-葡聚糖的相互作用，Nb-NAT 显示出比 NAT 更好的抗真菌效果。此外，浓度低于 0.5mg/ml 的 Nb 不影响 HCEC 的活力。与 NAT 相比，Nb-NAT 的细胞毒性和眼表面刺激性更小。针对β-葡聚糖的 Nb 减轻了烟曲霉（A. fumigatus）的毒力，并缓解了 FK 中的炎症反应。与 NAT 相比，Nb-NAT 治疗角膜可改善治疗效果。它降低了临床评分和炎症因子的表达水平。据我们所知，这项研究首次报道了一种针对β-葡聚糖的 Nb 和 Nb-NAT 用于治疗 FK。针对β-葡聚糖的 Nb 和 Nb-NAT 的这些独特功能可以作为控制包括 FK 在内的真菌感染的替代分子。
真菌性角膜炎是一种致盲率很高的角膜疾病。由于传统眼药水溶解度差、角膜毒性高，目前 FK 的治疗效果仍然有限。为了提高那他霉素治疗真菌性角膜炎（FK）的疗效，本研究通过制备一种针对β-葡聚糖的纳米抗体并将其与抗真菌药物那他霉素结合，开发了一种创新方法。针对β-葡聚糖的纳米抗体具有控制真菌病原体入侵和炎症的能力，这可能导致 FK 中角膜受损。与针对β-葡聚糖的纳米抗体结合显著增加了那他霉素的抗真菌能力并降低了其毒性。那他霉素与针对β-葡聚糖的纳米抗体的进一步应用可以扩展到其他由真菌病原体感染引起的疾病。
