Nicotine-induced endoplasmic reticulum (ER) stress in retinal pigment epithelium (RPE) cells is thought to be one pathological mechanism underlying age-related macular degeneration (AMD). ERp29 attenuates tobacco extract-induced ER stress and mitigates tight junction damage in RPE cells. Herein, we aimed to further investigate the role of ERp29 in nicotine-induced ER stress and choroidal neovascularization (CNV). We found that the expression of ERp29 and GRP78 in ARPE-19 cells was increased in response to nicotine exposure. Overexpression of ERp29 decreased the levels of GRP78 and the C/EBP homologous protein (CHOP). Knockdown of ERp29 increased the levels of GRP78 and CHOP while reducing the viability of ARPE-19 cells under nicotine exposure conditions. In the ARPE-19 cell/macrophage coculture system, overexpression of ERp29 decreased the levels of M2 markers and increased the levels of M1 markers. The viability, migration and tube formation of human umbilical vein endothelial cells (HUVECs) were inhibited by conditioned medium from the ERp29-overexpressing group. Moreover, overexpression of ERp29 inhibits the activity and growth of CNV in mice exposed to nicotine in vivo. Taken together, our results revealed that ERp29 attenuated nicotine-induced ER stress, regulated macrophage polarization and inhibited CNV.

Choroidoretinopathy is a major public health concern that causes significant vision impairment. Although therapeutic antibodies have demonstrated potential in treating these conditions, intravitreal injections remain invasive, associated with adverse effects, and require repeated traumatic administrations. Non-invasive drug delivery methods, such as eye drops, represent an ideal alternative but are limited by ocular barriers, making it difficult for drugs to effectively reach specific lesions. In this study, we introduce a novel reactive oxygen species (ROS)-responsive transmembrane peptide–antibody conjugate (PAC) designed for non-invasive, precise antibody delivery to the deep fundus region. The responsive PAC, termed trans-activator of transcription–polyethylene glycol–maleimide (TAT-MPEG)-antibody, is synthesized by linking transmembrane peptides TAT to maleimide via ROS-sensitive diselenide bonds, enabling efficient antibody conjugation. Following eye drop administration, TAT enhances ocular penetration, allowing the conjugate to traverse ocular barriers and deliver antibodies directly to the posterior segment. Moreover, the diselenide bonds facilitate antibody release in oxidative environments, ensuring targeted drug localization at disease sites. In mouse models of choroidal neovascularization and choroidal melanoma, this conjugate demonstrated significant therapeutic efficacy, highlighting its broad clinical potential for the treatment of choroidoretinopathy.