Etinal neurodegeneration caused by M ler cells (Wang et al., 2018b). Circ-ZNF609 includes a comparable function in retinal neurodegeneration induced by glaucoma by binding with miR-615 (Wang et al., 2018a). In AMD patients, circNR3C1 expression was identified to be downregulated within the blood serum (Chen et al., 2020a). Investigators additional assessed the attainable mechanism of this circRNA by way of RPE cell lines and found that circNR3C1 protected RPE functions via the circNR3C1miR-382-5p-PTEN network (Figure 4B). Retinoblastoma (Rb) is definitely an critical reason for blindness in early childhood (Liu et al., 2020). CircRNAs have also been shown to be dysregulated in RB and a few RB cell lines. It was discovered that hsa_circ_0001649 was drastically downregulated and could regulate apoptosis and cell proliferation by the AKT/mTOR signaling pathway (Xing et al., 2018). You’ll find at present handful of studies which have assessed the mechanism of circRNAs in retinal illnesses.CNS InjuryCircRNAs participate in different kinds of neuronal injury. To investigate the mechanisms of circRNAs in cerebral ischemiareperfusion-injury (IRI)-induced neuron injury, Lin et al. (2016) tested circRNA expression in HT22 cells with oxygenglucose deprivation/reoxygenation (OGD/R) and discovered that three circRNAs were upregulated and 12 were downregulated. It was additional shown that circPTK2 could inhibit miR-29b expression. Downregulated miR-29b expression can upregulate the JAK2/STAT3 signaling pathway and finally cause neuronal apoptosis induced by OGD-activated microglia (Wang et al., 2019). Irreversible axonal damage may be the principal cause of neurological dysfunction in neurodegenerative ailments or following traumatic injury. Mao et al. (2019a) located for the very first time that circRNAs could possibly be involved in axon regeneration of injured neurons. These outcomes showed that circ-Spidr Calcium Channel Antagonist Formulation enhances axon regrowth in vitro and in vivo. Moreover, the investigators discovered an additional circRNA that had the opposite impact. CircAnkib1 inhibits axon regeneration by inhibiting Schwann cell proliferation inside the sciatic nerve right after crush injury (Mao et al.,Frontiers in Molecular Biosciences | www.frontiersin.orgMarch 2021 | Volume 8 | ArticleLi et al.Circular RNAs in the Central Nervous SystemGliomaIn addition, some research have shown the function of circRNAs in nervous method tumors. Circ-ZNF264, circPCMTD1, and circTTBK2 (Figure 4C) market cell proliferation, migration and invasion in glioma cell lines by regulating their miRNAs (Zheng et al., 2017, 2019; Zhang et al., 2019). Circ-FBXW7 has a tumor suppressor effect in glioma cells by encoding a novel IL-10 Modulator Gene ID protein and is positively correlated with the general survival rate (Yang et al., 2018). A recent study identified that, apart from regulating cell growth and apoptosis, circ POSTN participated in aerobic glycolysis in glioma by way of the miR-361-5p/TPX2 axis (Lengthy et al., 2020). Moreover, a recent assessment reported that most circRNAs function as miRNA sponges in glioma (Sun et al., 2020). CircRNAs also play a part in psychiatric diseases which include bipolar disorder and significant depressive disorder (Luykx et al., 2019; Zhang Y. et al., 2020). Overall, the aforementioned research indicate that circRNAs play a essential part in many neurological illnesses. Nevertheless, the underlying mechanisms of circRNAs in quite a few diseases have not been completely elucidated. Further study is required to elucidate how circRNAs exert their effects biologically.proof is necessary. A current study by Xu et al. (2020) showed that ci.