Oxidative stress in retinal pigment epithelium (RPE) cells may contribute to the progression of age-related macular degeneration. Thymoquinone (TQ), an active component derived from Nigella sativa, possesses antioxidative effect. However, the role of TQ in RPE cells under oxidative stress condition remains unclear. The present study aimed to examine the protective effect of TQ against hydrogen peroxide (H 2 O 2 )-induced oxidative stress in human RPE cells. Our results showed that TQ improved the cell viability and apoptosis in H 2 O 2induced ARPE cells. We also found that the levels of reactive oxygen species and malondialdehyde induced by H 2 O 2 were reduced after the pretreatment of TQ. In addition, the inhibitory effect of H 2 O 2 on the glutathione (GSH) level and superoxide dismutase activity was markedly attenuated by TQ pretreatment. Moreover, TQ enhanced the activation of Nrf2/heme oxygenase 1 (HO-1) signaling pathway in H 2 O 2 -induced ARPE cells. Knockdown of Nrf2 abolished the protective effect of TQ on H 2 O 2 -induced oxidative damage. These results suggested that TQ protected ARPE cells from H 2 O 2 -induced oxidative stress and apoptosis via the Nrf2/HO-1 signaling pathway. K E Y W O R D S age-related macular degeneration (AMD), apoptosis, Nrf2/heme oxygenase 1 (HO-1) signaling pathway, oxidative stress, retinal pigment epithelium (RPE) cells, thymoquinone (TQ)

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MicroRNAs are a set of highly conserved non-coding RNAs that control gene expression at the post-transcriptional/translational levels by binding to the 3′-UTR of diverse target genes. Increasing evidence indicates that miRNAs not only play a vital role in many biological processes, but they are also frequently deregulated in pathological conditions, including cancer. The miR-320 family is one of many tumor suppressor families and is composed of five members, which has been demonstrated to be related to the repression of epithelial-mesenchymal transition (EMT) inhibition, cell proliferation, and apoptosis. Moreover, this family has been shown to regulate drug resistance, and act as a potential biomarker for the diagnosis, prognosis, and prediction of cancer. In this review, we summarized recent research with reference to the tumor suppressor function of miR-320 and the regulation mechanisms of miR-320 expression. The collected evidence shown here supports that miR-320 may act as a novel biomarker for cancer prognosis and therapeutic response to cancer treatment.

From this study, the distributions of tHcy levels were skewed to the right and the boys had higher plasma tHcy levels than girls. Plasma tHcy levels were significantly positively associated with BMI among boys. Further studies are needed to evaluate the relationship between tHcy and CVD risk factors among children for the better prevention of heart disease in early life.