Circular RNA TTC3 regulates cerebral ischemia-reperfusion injury and neural stem cells by miR-372-3p/TLR4 axis in cerebral infarction

Abstract

Background Stroke serves as a prevalent cerebrovascular disorder with severe cerebral ischemia/reperfusion (CIR) injury, in which neural stem cells (NSCs) play critical roles in the recovery of cerebral function. Circular RNAs (circRNAs) have been widely found to participate in stroke and NSC modulation. However, the role of circRNA TTC3 (circTTC3) in the regulation of CIR injury and NSCs remains elusive. Here, we aimed to explore the impact of circTTC3 on CIR injury and NSCs. Methods The middle cerebral artery occlusion/repression (MCAO/R) model was established in C57BL/6J mice. The primary astrocytes were isolated from the cerebellum from C57BL/6J mice. The primary NSCs were obtained from rat embryos. The effect of circTTC3 on CIR injury and NSCs was analyzed by TTC staining, qPCR, Western blot, LDH colorimetric kits, MTT assays, Annexin V-FITC Apoptosis Detection Kit, luciferase reporter gene assays, and others in the system. Results Significantly, the expression of circTTC3 was elevated in the MCAO/R mice and oxygen and glucose deprivation (OGD)-treated astrocytes. The depletion of circTTC3 attenuated cerebral infarction, neurological score, and brain water content. The OGD treatment induced apoptosis and the levels of lactate dehydrogenase (LDH) in the astrocytes, in which circTTC3 depletion reduced this phenotype in the system. Moreover, the depletion of circTTC3 promoted the proliferation and upregulated the nestin and β-tubulin III expression in NSCs. Mechanically, circTTC3 was able to sponge miR-372-3p, and miR-372-3p can target Toll-like receptor 4 (TLR4) in NSCs. The miR-372-3p inhibitor or TLR4 overexpression could reverse circTTC3 depletion-mediated astrocyte OGD injury and NSC regulation. Conclusion Thus, we conclude that circTTC3 regulates CIR injury and NSCs by the miR-372-3p/TLR4 axis in cerebral infarction. Our finding presents new insight into the mechanism by which circTTC3 modulates CIR injury and NSC dysfunction. CircTTC3, miR-372-3p, and TLR4 may serve as potential targets for the treatment of CIR injury during stroke.

Long Non-coding RNAs and Circular RNAs: Insights Into Microglia and Astrocyte Mediated Neurological Diseases

“…In this review, the lncRNA/circRNA-miRNA-mRNA regulatory network also exists in microglia and astrocyte mediated neurological diseases, including SCI (Figure 1; Shao et al, 2020; FIGURE 1 | The lncRNA/circRNA-miRNA-mRNA regulatory network in microglia and astrocyte regulated neurological diseases. Xu S. et al, 2020;Zhao Q. et al, 2020;Cui et al, 2021;Xiang et al, 2021;Chen et al, 2022), TBI (He et al, 2021;Liu N. et al, 2021;Meng et al, 2021), cerebral IRI (Figure 1; Wang et al, 2020c;Yang et al, 2021), stroke (Figure 1; Qi et al, 2017;Han B. et al, 2018;Tian et al, 2021;Zhang M. et al, 2021), epilepsy (Figure 1; Feng et al, 2020;Han C. L. et al, 2020;Wan and Yang, 2020;Xiaoying et al, 2020), neuropathic pain (Figure 1; Chen M. et al, 2020), PD (Figure 1; Cao et al, 2018Cao et al, , 2021, and depression (Figure 1; . We also found that some therapies can impair the ncRNA-glial cell axis and thus inhibit disease development.…”

“…Depleting circTTC3 suppresses OGD-induced astrocyte injury and promotes NSC proliferation and differentiation via the miR-372-3p-TLR4 axis. The circTTC3 knockdown in MCAO/R mice can alleviate cerebral IRI (Yang et al, 2021).…”

Microarray Analysis Identifies Key Differentially Expressed Circular RNAs in Aged Mice With Postoperative Cognitive Dysfunction

“…For instance, circRNA_2837 targets miR-34 family members to regulate LC3-II/p62 and protect neurons by autophagy in the sciatic nerve injury model (Zhou et al, 2018). In neural stem cells, circRNA TTC3 sponges miR-372-3p to regulate TLR4 expression and prevent cerebral ischemia reperfusion injury (Yang et al, 2021). With a new understanding of the ceRNA networks in different diseases, therapies targeting ceRNAs rather than miRNAs alone may become more significant and valuable (Bak and Mikkelsen, 2014).…”

Non-Coding RNA Regulatory Network in Ischemic Stroke

“…These then participate in the process of brain repair and play an essential role in IS ( 84 ). Yang et al explored the effects of circRNA-TTC3 on ischemia-reperfusion injury and NSCs ( 85 ). TTC3 expression was significantly increased in hypoxic astrocytes, and its target was miR-372-3p.…”