Study on the involvement of microglial S100A8 in neuroinflammation and microglia activation during migraine attacks.

BACKGROUND: Microglia is the primary source of inflammatory factors during migraine attacks. This study aims to investigate the role of microglia related genes (MRGs) in migraine attacks. METHODS: The RNA sequencing results of migraineurs and the panglaodb database were used to obtain differentially expressed genes (DEGs) in migraine related to microglia. A migraine rat model was established for validating and localizing of the MRGs, and subsequent screening for target genes was conducted. A shRNA was designed to interference the expression of target genes and administered into the trigeminal ganglion (TG) of rats. Pain sensitivity in rats was evaluated via the hot water tail-flick (HWTF) and formalin-induced pain (FIP) experiments. ELISA was used to quantify the levels of inflammatory cytokines and CGRP. WB and immunofluorescence assays were applied to detect the activation of microglia. RESULTS: A total of five DEGs in migraine related to microglia were obtained from RNA sequencing and panglaodb database. Animal experiments showed that these genes expression were heightened in the TG and medulla oblongata (MO) of migraine rats. The gene S100A8 co-localized with microglia in both TG and MO. The HWTF and FIP experiments demonstrated that interference with S100A8 alleviated the sense of pain in migraine rats. Moreover, the levels of TNFα, IL-1ß, IL-6, and CGRP in the TG and MO of rats in the model rats were increased, and the expression of microglia markers IBA-1, M1 polarization markers CD86 and iNOS was upregulated. Significantly, interference with S100A8 reversed these indicators. CONCLUSION: Interference with S100A8 in microglia increased the pain threshold during migraine attacks, and inhibited neuroinflammation and microglia activation.

miR-16 regulates proliferation and apoptosis of pituitary adenoma cells by inhibiting HMGA2.

Previous studies have revealed that elevated expression of high mobility group A2 (HMGA2) is closely associated with the occurrence of pituitary adenomas (PAs). The expression of microRNA (miR)-16 is deregulated in PA tissues. Bioinformatics analysis has demonstrated that there is a complementary region between seed region of miR-16 and 3'-untranslated region (3'-UTR) of HMGA2 gene. In the present study, it was investigated whether miR-16 may regulate the expression of HMGA2 and whether it is involved in the pathogenesis of PAs. A total of 52 patients with PAs were recruited. Normal brain tissues obtained from 12 patients with traumatic brain injury were used as controls. The association between miR-16 and HMGA2 was validated using dual-luciferase reporter gene assay. HP75 cells were cultured in vitro and divided into the following groups: miR control, miR-16 mimic, small interfering RNA (si)-negative control, si-HMGA2 and miR-16 mimic+si-HMGA2 groups. The expression of miR-16 and HMGA2 in HP75 cells was determined using qRT-PCR and western blot. Cell proliferation was detected using the Cell Counting Kit-8 assay and apoptosis was detected using the TdT-UTP nick end labeling assay. Compared with normal pituitary tissues, the expression of miR-16 in PA tissues was significantly decreased, while the mRNA and protein levels of HMGA2 were significantly increased. miR-16 targeted the 3'-UTR of HMGA2 gene and regulated the expression of HMGA2. Transfection with siRNAs targeting HMGA2 and/or miR-16 mimics inhibited the expression of HMGA2 and the proliferative ability of HP75 cells, whereas it increased apoptosis of HP75 cells. The downregulation of miR-16 and upregulation of HMGA2 were involved in the pathogenesis of PAs. Thus, it is hypothesized that miR-16 inhibited the proliferation and promoted apoptosis of HP75 cells by inhibiting HMGA2 expression.