Role of p75 neurotrophin receptor in neuronal autophagy in intracerebral hemorrhage in rats through the mTOR signaling pathway

Expression profile of circular RNAs in blood samples of Northern Chinese males with intracerebral hemorrhage shows downregulation of hsa-circ-0090829

Circular RNAs (circRNAs) are involved in several neurological disorders; however, the mechanisms underlying their involvement remain to be clarified. We attempted to explore the expression profiles of circRNAs and their potential functions and mechanisms in the pathogenesis of intracerebral hemorrhage (ICH) in Northern Chinese males. The microarray results showed that 50 circRNAs were significantly upregulated, while 194 circRNAs were significantly downregulated in ICH patients compared with healthy controls (p < 0.05). After bioinformatics analysis, a circRNA-microRNA-messenger RNA network and a protein-protein interaction network were constructed. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses showed that the neurotrophin signaling pathway, long-term potentiation, and the mitogen-activated protein kinase pathway are potentially implicated in ICH pathophysiology. The quantitative real-time polymerase chain reaction results revealed that hsa-circ-0090829 was significantly downregulated in ICH. The receiver operating characteristic curve analysis showed that the area under the curve of hsa-circ-0090829 between ICH and healthy controls was 0.807. Furthermore, the dual-luciferase assay showed that hsa-circ-0090829 sponged miR-526b-5p. This study reports the altered expression of circRNAs and identifies the potential functions of these circRNAs in ICH. Our results may facilitate further mechanistic research on circRNAs in ICH and provide probable novel diagnostic biomarkers and therapeutic targets for ICH.

The use of multiple datasets to identify autophagy-related molecular mechanisms in intracerebral hemorrhage

Background: Intracerebral hemorrhage (ICH) is a stroke syndrome with high mortality and disability rates, but autophagy’s mechanism in ICH is still unclear. We identified key autophagy genes in ICH by bioinformatics methods and explored their mechanisms.

Methods: We downloaded ICH patient chip data from the Gene Expression Omnibus (GEO) database. Based on the GENE database, differentially expressed genes (DEGs) for autophagy were identified. We identified key genes through protein–protein interaction (PPI) network analysis and analyzed their associated pathways in Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). Gene-motif rankings, miRWalk and ENCORI databases were used to analyze the key gene transcription factor (TF) regulatory network and ceRNA network. Finally, relevant target pathways were obtained by gene set enrichment analysis (GSEA).

Results: Eleven autophagy-related DEGs in ICH were obtained, and IL-1B, STAT3, NLRP3 and NOD2 were identified as key genes with clinical predictive value by PPI and receiver operating characteristic (ROC) curve analysis. The candidate gene expression level was significantly correlated with the immune infiltration level, and most of the key genes were positively correlated with the immune cell infiltration level. The key genes are mainly related to cytokine and receptor interactions, immune responses and other pathways. The ceRNA network predicted 8,654 interaction pairs (24 miRNAs and 2,952 lncRNAs).

Conclusion: We used multiple bioinformatics datasets to identify IL-1B, STAT3, NLRP3 and NOD2 as key genes that contribute to the development of ICH.

Autophagy regulates inflammation in intracerebral hemorrhage: Enemy or friend?

Intracerebral hemorrhage (ICH) is the second-largest stroke subtype and has a high mortality and disability rate. Secondary brain injury (SBI) is delayed after ICH. The main contributors to SBI are inflammation, oxidative stress, and excitotoxicity. Harmful substances from blood and hemolysis, such as hemoglobin, thrombin, and iron, induce SBI. When cells suffer stress, a critical protective mechanism called "autophagy" help to maintain the homeostasis of damaged cells, remove harmful substances or damaged organelles, and recycle them. Autophagy plays a critical role in the pathology of ICH, and its function remains controversial. Several lines of evidence demonstrate a pro-survival role for autophagy in ICH by facilitating the removal of damaged proteins and organelles. However, many studies have found that heme and iron can aggravate SBI by enhancing autophagy. Autophagy and inflammation are essential culprits in the progression of brain injury. It is a fascinating hypothesis that autophagy regulates inflammation in ICH-induced SBI. Autophagy could degrade and clear pro-IL-1β and apoptosis-associated speck-like protein containing a CARD (ASC) to antagonize NLRP3-mediated inflammation. In addition, mitophagy can remove endogenous activators of inflammasomes, such as reactive oxygen species (ROS), inflammatory components, and cytokines, in damaged mitochondria. However, many studies support the idea that autophagy activates microglia and aggravates microglial inflammation via the toll-like receptor 4 (TLR4) pathway. In addition, autophagy can promote ICH-induced SBI through inflammasome-dependent NLRP6-mediated inflammation. Moreover, some resident cells in the brain are involved in autophagy in regulating inflammation after ICH. Some compounds or therapeutic targets that regulate inflammation by autophagy may represent promising candidates for the treatment of ICH-induced SBI. In conclusion, the mutual regulation of autophagy and inflammation in ICH is worth exploring. The control of inflammation by autophagy will hopefully prove to be an essential treatment target for ICH.

An Shen Ding Zhi Ling Ameliorates the Symptoms of Attention Deficit Hyperactivity Disorder via Modulating Brain-Derived Neurotrophic Factor-Related Signaling Pathways

Attention deficit hyperactivity disorder (ADHD) is a common childhood neurodevelopmental disorder. It may impact the cognitive and social functions throughout childhood and determine adult outcomes. Dopamine (DA) deficiency theory is the pathogenesis of ADHD that is recognized by most international literature. Existing studies have shown that DA deficiency is caused by the abnormal function of the DA transporter and an imbalance in the DA receptor functionality. Recent clinical and experimental studies have found that the brain-derived neurotrophic factor (BDNF)/tropomyosin receptor kinase B (TrkB) signaling pathway acts a pivotal part in DA vesicle circulation and ADHD pathogenesis. An Shen Ding Zhi Ling (ASDZL) is a traditional Chinese medicine (TCM) prescription, which was widely prescribed to treat ADHD in Jiangsu, China, but its therapeutic mechanism is unclear. Therefore, we constructed a spontaneously hypertensive rat (SHR) model to explain its mechanism. SHRs were randomly assigned to four groups: SHR model group (vehicle), methylphenidate hydrochloride group (MPH), ASDZL group, and 7,8-dihydroxyflavone group (7,8-DHF). At the same time, the above groups were given continuous medication for four weeks. The results show that ASDZL, MPH, and 7,8-DHF group could significantly improve the spatial memory of SHRs in the Morris water maze tests. ASDZL increased the levels of BDNF, TrkB, p75 neurotrophin receptor (p75), C-Jun N-terminal kinases 1 (JNK1), and nuclear factor kappa B (NF-κB) in the prefrontal cortex (PFC) and hippocampus synaptosome of SHRs. The results of this study suggest that ASDZL can relieve the symptoms of ADHD in SHRs by regulating the balance between the BDNF/TrkB signaling pathway (promoting vesicle circulation) and the BDNF/P75/JNK1/NF-κB signaling pathway (inhibiting vesicle circulation) within the PFC and hippocampus synaptosome to increase the DA concentration in the synaptic cleft. The BDNF/TrkB signal pathway within the PFC and hippocampus synaptosome was activated by 7,8-DHF to increase DA concentration in the synaptic cleft. Whether 7,8-DHF can activate or inhibit the BDNF/P75 signaling pathway remains unclear.