Epigenetics of amphetamine-induced sensitization: HDAC5 expression and microRNA in neural remodeling

Abstract

BackgroundHistone deacetylase (HDAC) activities modify chromatin structure and play a role in learning and memory during developmental processes. Studies of adult mice suggest HDACs are involved in neural network remodeling in brain repair, but its function in drug addiction is less understood. We aimed to examine in vivo HDAC5 expression in a preclinical model of amphetamine-induced sensitization (AIS) of behavior. We generated specific contrast agents to measure HDAC5 levels by in vivo molecular contrast-enhanced (MCE) magnetic resonance imaging (MRI) in amphetamine-naïve mice as well as in mice with AIS. To validate the MRI results we used ex vivo methods including in situ hybridization, RT-PCR, immunohistochemistry, and transmision electron microscopy.MethodsWe compared the expression of HDAC5 mRNA in an acute exposure paradigm (in which animals experienced a single drug exposure [A1]) and in a chronic-abstinence-challenge paradigm (in which animals were exposed to the drug once every other day for seven doses, then underwent 2 weeks of abstinence followed by a challenge dose [A7WA]). Control groups for each of these exposure paradigms were given saline. To delineate how HDAC5 expression was related to AIS, we compared the expression of HDAC5 mRNA at sequences where no known microRNA (miR) binds (hdac5AS2) and at sequences where miR-2861 is known to bind (miD2861). We synthesized and labeled phosphorothioated oligonucleic acids (sODN) of hdac5AS2 or miD2861 linked to superparamagentic iron oxide nanoparticles (SPION), and generated HDAC5-specific contrast agents (30 ± 20 nm, diameter) for MCE MRI; the same sequences were used for primers for TaqMan® analysis (RT-qPCR) in ex vivo validation. In addition, we used subtraction R2* maps to identify regional HDAC5 expression.ResultsNaïve C57black6 mice that experience acute exposure to amphetamine (4 mg/kg, by injection intraperitoneally) show expression of both total and phosphorylated (S259) HDAC5 antigens in GFAP+ and GFAP− cells, but the appearance of these cells was attenuated in the chronic paradigm. We found that MCE MRI reports HDAC5 mRNA with precision in physiological conditions because the HDAC5 mRNA copy number reported by TaqMan analysis was positively correlated (with a linear coefficient of 1.0) to the ΔR2* values (the frequency of signal reduction above background, 1/s) measured by MRI. We observed SPION-mid2861 as electron dense nanoparticles (EDNs) of less than 30 nm in the nucleus of the neurons, macrophages, and microglia, but not in glia and endothelia. We found no preferential distribution in any particular type of neural cells, but observed scattered EDNs of 60–150 nm (dia) in lysosomes. In the acute paradigm, mice pretreated with miD2861 (1.2 mmol/kg, i.p./icv) exhibited AIS similar to that exibited by mice in the chronic exposure group, which exhibited null response to mid2861 pretreatment. Moreover, SPION-miD2861 identified enhanced HDAC5 expression in the lateral septum and the striatum after amphetamine, where we found neurprogenitor cel...

Human milk extracellular vesicle miRNA expression and associations with maternal characteristics in a population-based cohort from the Faroe Islands

“…The second most highly expressed miRNA in human milk EVs, miR-3197, has been suggested to be semen-specific in forensic studies 53,54 , however, miR-3197 expression was detected in human mesenchymal stem cells 55 , human placenta 56 , serum from patients with hepatocellular carcinoma 57 . miR-1286 is a putative HDAC5 (histone deacetylase 5) repressor, which in turn regulates RUNX2 (Runt-Related Transcription Factor 2), and playing a role in osteogenesis and osteoporosis [58][59][60] . We examined correlations between highly expressed miRNAs in our population to determine which miR-NAs may be co-regulated.…”

Immunological effects of iron oxide nanoparticles and iron-based complex drug formulations: Therapeutic benefits, toxicity, mechanistic insights, and translational considerations

“…Although it is in a very early stage, this technology was found to be more efficient and cost-effective, and it may be expanded for broader proteomics and metabolomics applications. With a similar approach, Liu et al functionalized the SPION with HDAC5- and miRNA-specific labeling to detect the levels of HDAC5 mRNA in vivo using contrast-enhanced (MCE)–MRI [46], demonstrating a novel application in epigenetics. More recently, several studies have indicated a possible application of IONP formulations in anticancer treatments [38–40, 47–49].…”

Role of epigenetic regulatory enzymes in animal models of mania induced by amphetamine and paradoxical sleep deprivation

“…Chronic administration of d‐amph was able to increase HDAC activity in hippocampus and striatum but not in frontal cortex. Other studies demonstrated that chronic administration of amphetamine was able to increase HDAC activity in the frontal cortex of rats (Stertz et al., 2014) and HDAC5 expression in the lateral septum and the striatum of mice (Liu & Liu, 2016). As expected, VPA and SB treatment decreased HDAC activity in both saline‐ and d‐amph‐treated animals compared to the control group—except frontal cortex and striatum, where VPA had no effect and lower effect, respectively.…”