Differential Expression of miRNAs and Behavioral Change in the Cuprizone-Induced Demyelination Mouse Model

Abstract

The demyelinating diseases of the central nervous system involve myelin abnormalities, oligodendrocyte damage, and consequent glia activation. Neurotoxicant cuprizone (CPZ) was used to establish a mouse model of demyelination. However, the effects of CPZ on microRNA (miRNA) expression and behavior have not been clearly reported. We analyzed the behavior of mice administered a diet containing 0.2% CPZ for 6 weeks, followed by 6 weeks of recovery. Rotarod analysis demonstrated that the treated group had poorer motor coordination than control animals. This effect was reversed after 6 weeks of CPZ withdrawal. Open-field tests showed that CPZ-treated mice exhibited significantly increased anxiety and decreased exploratory behavior. CPZ-induced demyelination was observed to be alleviated after 4 weeks of CPZ treatment, according to luxol fast blue (LFB) staining and myelin basic protein (MBP) expression. miRNA expression profiling showed that the expression of 240 miRNAs was significantly changed in CPZ-fed mice compared with controls. Furthermore, miR-155-5p and miR-20a-5p upregulations enhanced NgR induction through Smad 2 and Smad 4 suppression in demyelination. Taken together, our results demonstrate that CPZ-mediated demyelination induces behavioral deficits with apparent alterations in miRNA expression, suggesting that differences in miRNA expression in vivo may be new potential therapeutic targets for remyelination.

The Role of MicroRNAs in Repair Processes in Multiple Sclerosis

“…In the cuprizone model, miR-155 and miR-20a upregulation during demyelination may also be important for neuronal survival and remyelination by inducing the Nogo Receptor via suppression of mothers against decapentaplegic homolog 2 (SMAD2) and SMAD4. However, this study was limited to whole-cerebrum miRNA expression [ 81 ]. Finally, in EAE, several miRNAs—miR-7a, miR-101a, miR-142a, miR-199b, miR-203, miR-205, miR-340, miR-370, miR-374b, miR-381, miR-1969 and miR-7056—are upregulated in retinal ganglion cells and in silico analysis suggests that they may impair neuroprotective pathways, which in turn may present an obstacle to efficient remyelination [ 105 ].…”

miRNAs in Microglia: Important Players in Multiple Sclerosis Pathology

“…Inhibition of miR-155 also reduces EAE progression, suppressing both T helper cell differentiation and production of TNF-α, which are pro-inflammatory processes normally mediated by activated microglia ( Zhang et al., 2014a ). In addition, miR-155 is significantly upregulated following cuprizone mediated demyelination ( Han et al., 2020 ). In MS, miR-155 expression consistently upregulated in both peripheral circulation and CNS lesions( Junker et al., 2009 ; Paraboschi et al., 2011 ; Waschbisch et al., 2011 ; Moore et al., 2013 ; Zhang et al., 2014a ; Piket et al., 2019 ; Fritsche et al., 2020 ).…”

“…Another major regulator of the innate immunity is miR-146a, which is consistently upregulated in animal models and MS patient lesions, serum and CSF of MS patients ( Junker et al., 2009 ; Fenoglio et al., 2011 ; Lescher et al., 2012 ; Bergman et al., 2013 ; Yang et al., 2014 ; Zhang et al., 2014a ; 2017 ; Munoz-San Martin et al., 2019 ; Han et al., 2020 ). miR-146a expression is induced by NF-kβ mediated inflammation and initiates negative feedback of inflammatory microglial activation by targeting key genes (Including TRAF6 and IRAK1) in the NF-kβ and JAK/STAT pathways ( Taganov et al., 2006 ) ( Figure 3 .).…”

“…Lastly in terms of neuroprotective miRNAs is miR-199b, another promising biomarker of MS progression associated with microglial repair and inhibition of chronic activation. Upregulated in animal models and in MS patient lesions, miR-199b expression in serum is negatively correlated with clinical disability (EDSS) ( Bergman et al., 2013 ; Tripathi et al., 2019 ; Han et al., 2020 ). The action of miR-199b is considered protective, inhibiting microglial inflammation by targeting the NF-kβ pathway via IKKβ ( Zhou et al., 2016a ) ( Figure 3 .).…”

“…Numerous miRNAs have been identified which promote microglial inflammation in MS. The most well defined is (Louafi et al, 2010;Bala et al, 2011;Cardoso et al, 2012) Promotes microglial inflammation (Guedes et al, 2013;Guo et al, 2019) Upregulated in EAE (Lescher et al, 2012;Zhang et al, 2014a;Shakerian et al, 2018;Venkatesha et al, 2018) Upregulated in cuprizone (Han et al, 2020) Upregulated in PBMCS (Paraboschi et al, 2011;Waschbisch et al, 2011;Moore et al, 2013;Dolati et al, 2018b) Upregulated in serum (Zhang et al, 2014a) Upregulated in all MS lesion types (Junker et al, 2009;Moore et al, 2013;Fritsche et al, 2020) miR-145 NURR1, ARF6 (Xie et al, 2017; Promotes microglial inflammation (Xie et al, 2017) Downregulated in cuprizone (Han et al, 2020) Upregulated in PBMCs…”