Inhibition of MicroRNA-96 Ameliorates Cognitive Impairment and Inactivation Autophagy Following Chronic Cerebral Hypoperfusion in the Rat

Abstract

Background/Aims: Chronic cerebral hypoperfusion (CCH) is a high-risk factor for vascular dementia and Alzheimer’s disease. Autophagy plays a critical role in the initiation and progression of CCH. However, the underlying mechanisms remain unclear. In this study, we identified the effect of a microRNA (miR) on autophagy under CCH. Methods: A CCH rat model was established by two-vessel occlusion (2VO). Learning and memory abilities were assessed by the Morris water maze. The protein levels of LC3, beclin-1, and mTOR were detected by western blotting and immunofluorescence assays, miR-96 expression was assessed by real-time PCR, luciferase assays were used to determine the effect of miR-96 on the 3′ untranslated region (UTR) of mTOR, and the number of autophagosomes was examined by electron microscopy. Results: The level of miR-96 was significantly increased in 2VO rats, and inhibition of miR-96 ameliorated the cognitive impairment induced by 2VO. Furthermore, the number of LC3- and beclin-1-positive autophagosomes was increased in 2VO rats, and was decreased after miR-96 antagomir injection. However, the protein level of mTOR was reduced in 2VO rats, and it was down-regulated by miR-96 overexpression and up-regulated by miR-96 inhibition in 2VO rats and primary culture cells. Moreover, the luciferase activity of the 3′-UTR of mTOR was suppressed by miR-96, which was relieved by mutation of the miR-96 binding sites. Conclusion: Our study demonstrated that miR-96 may play a key role in autophagy under CCH by regulating mTOR; therefore, miR-96 may represent a potential therapeutic target for CCH.

Adenosine A2A Receptors in Bone Marrow-Derived Cells Attenuate Cognitive Impairment in Mice After Chronic Hypoperfusion White Matter Injury

“…IL-1β receptor inhibitors and IL-1β knockout mice block the IL-1β signaling pathway, thereby inducing oligodendrocyte premature cell migration to the periphery of the corpus callosum, and avoiding white matter damage and reversing chronic hypoperfusion-induced cognitive dysfunction by improving the local inflammatory environment [26]. MiR-181c [27] and MiR-96 [28] can ameliorate cognitive dysfunction by regulating autophagy in CCH [29]. In general, demyelination, inflammatory responses, and mitochondrial dysfunction are common pathways leading to cognitive dysfunction [30,31], which can ameliorate the prognosis of chronic cortical hypoperfusion by reducing white matter lesions.…”

MicroRNA alterations in neuropathologic cognitive disorders with an emphasis on dementia: Lessons from animal models

“…Instead, inhibition of miR‐96 ameliorated cognitive impairment and reduced autophagy, autophagosomes, light chain 3, and beclin‐1. Additionally, expression of mTOR is controlled by miR‐96 in both in vivo and vitro (P. Liu et al, 2018). While the angiogenic miRNA, miR‐126, is a regulator of vascular function, its serological level was declined following VD.…”

“…Instead, inhibition of miR-96 ameliorated cognitive impairment and reduced autophagy, autophagosomes, light chain 3, and beclin-1. Additionally, expression of mTOR is controlled by miR-96 in both in vivo and vitro (P Liu et al, 2018)…”

Ambiguous Effects of Autophagy Activation Following Hypoperfusion/Ischemia

“…Most of the pharmacological treatments known to be protective against neuronal damage induced by CBH are supposed to act as ATG inhibitors [ 86 , 103 , 128 , 173 , 174 , 175 , 176 , 177 ]. In particular, although characterized by different mechanisms of action, most reports emphasize the suppression of the ATG activation occurring in CBH [ 86 , 101 , 102 , 174 , 175 , 176 , 177 ]. This line of evidence suggests that the micro-balance working for ATG in CBH is shifted towards a deleterious effect of ATG on neuronal survival.…”