miR-142 downregulation alleviates rat PTSD-like behaviors, reduces the level of inflammatory cytokine expression and apoptosis in hippocampus, and upregulates the expression of fragile X mental retardation protein

• Published in: Journal of neuroinflammation Vol. 18; no. 1; p. 17
• Main Authors: Nie, Peng-Yin, Tong, Lei, Li, Ming-Da, Fu, Chang-Hai, Peng, Jun-Bo, Ji, Li-Li
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 06.01.2021; BioMed Central; BMC
• Subjects: Anxiety; Apoptosis; Behavior; Care and treatment; Cytokines; FMR1 protein; FMRP; Fragile X syndrome; Gene expression; Genetic aspects; Health aspects; Hippocampus; Hippocampus (Brain); IL-1β; Inflammation; Intellectual disabilities; Interleukin 6; Laboratory animals; Memory; MicroRNA; miR-142; miRNA; Morphology; mRNA; NF-κB; NF-κB protein; Post traumatic stress disorder; Postsynaptic density proteins; Protein biosynthesis; Proteins; Rodents; Swimming; Synapsin I; Tumor necrosis factor-TNF; Tumor necrosis factor-α; China; NF-κB; Inflammation; miR-142; FMRP; Post-traumatic stress disorder
• ISSN: 1742-2094; 1742-2094
• DOI: 10.1186/s12974-020-02064-0

FMRP is a selective mRNA-binding protein that regulates protein synthesis at synapses, and its loss may lead to the impairment of trace fear memory. Previously, we found that FMRP levels in the hippocampus of rats with post-traumatic stress disorder (PTSD) were decreased. However, the mechanism underlying these changes remains unclear. Forty-eight male Sprague-Dawley rats were randomly divided into four groups. The experimental groups were treated with the single-prolonged stress (SPS) procedure and injected with a lentivirus-mediated inhibitor of miR-142-5p. Behavior test as well as morphology and molecular biology experiments were performed to detect the effect of miR-142 downregulation on PTSD, which was further verified by in vitro experiments. We found that silence of miRNA-142 (miR-142), an upstream regulator of FMRP, could alleviate PTSD-like behaviors of rats exposed to the SPS paradigm. MiR-142 silence not only decreased the levels of proinflammatory mediators, such as interleukin-1β, interleukin-6, and tumor necrosis factor-α, but also increased the expressive levels of synaptic proteins including PSD95 and synapsin I in the hippocampus, which was one of the key brain regions associated with PTSD. We further detected that miR-142 silence also downregulated the transportation of nuclear factor kappa-B (NF-κB) into the nuclei of neurons and might further affect the morphology of neurons. The results revealed miR-142 downregulation could alleviate PTSD-like behaviors through attenuating neuroinflammation in the hippocampus of SPS rats by binding to FMRP.