A transcriptomics and molecular biology based investigation reveals the protective effect and mechanism of carnosol on t-BHP induced HRMECs via Nrf2 signaling pathway

Human retinal microvascular endothelial cells (HRMECs) injury plays an essential role in the pathogenesis of diabetic retinopathy (DR). As one of the crucial pathogenetic factors, oxidative stress induces HRMECs apoptosis and microvascular lesions. Nuclear factor erythroid 2-related factor 2 (Nrf2) acts as a molecular switch in oxidative stress-induced HRMECs injury. The present study was designed to investigate the protective effect and underlying mechanism of carnosol, a potential Nrf2 agonist, in tert-butyl hydroperoxide (t-BHP) induced HRMECs oxidative stress injury. In this study, carnosol was found to inhibit HRMECs injury induced by t-BHP. Transcriptomics and molecular biology illustrated that the mechanism was associated with oxidative stress, vascular system development, apoptosis, cell cycle, cell adhesion, cytoskeleton, and nitric oxide biosynthesis. Carnosol directly scavenged free radicals or activated the Nrf2 signaling pathway to alleviate HRMECs oxidative stress. ML385 pretreatment or Nrf2 small interference RNA (siRNA) inhibited the protective effect of carnosol on HRMECs injury. Moreover, the apoptosis and cell cycle arrest in HRMECs were suppressed by carnosol. Treatment with carnosol could also effectively regulate the adhesion and cytoskeleton. Overall, our data provide a systematic perspective for the mechanism of carnosol against HRMECs oxidative stress injury and reveal that carnosol may be a candidate drug for DR therapy.