ABSTRACT
Microglia migrate to the cerebral cortex during early embryonic stages. However, the precise mechanisms underlying microglia migration remain incompletely understood. As an extracellular matrix protein, Netrin-1 is involved in modulating the motility of diverse cells. In this paper, we found that Netrin-1 promoted microglial BV2 cell migration in vitro. Mechanism studies indicated that the activation of GSK3ß activity contributed to Netrin-1-mediated microglia migration. Furthermore, Integrin α6/ß1 might be the relevant receptor. Single-cell data analysis revealed the higher expression of Integrin α6 subunit and ß1 subunit in microglia in comparison with classical receptors, including Dcc, Neo1, Unc5a, Unc5b, Unc5c, Unc5d, and Dscam. Microscale thermophoresis (MST) measurement confirmed the high binding affinity between Integrin α6/ß1 and Netrin-1. Importantly, activation of Integrin α6/ß1 with IKVAV peptides mirrored the microglia migration and GSK3 activation induced by Netrin-1. Finally, conditional knockout (CKO) of Netrin-1 in radial glial cells and their progeny led to a reduction in microglia population in the cerebral cortex at early developmental stages. Together, our findings highlight the role of Netrin-1 in microglia migration and underscore its therapeutic potential in microglia-related brain diseases.
Subject(s)
Cell Movement , Microglia , Netrin-1 , Netrin-1/metabolism , Netrin-1/genetics , Microglia/metabolism , Animals , Mice , Mice, Knockout , Cerebral Cortex/metabolism , Cerebral Cortex/cytology , Glycogen Synthase Kinase 3 beta/metabolism , Glycogen Synthase Kinase 3 beta/genetics , Cell Line , Integrin beta1/metabolism , Integrin beta1/geneticsABSTRACT
Behavioral and clinical studies have revealed a critical role of substance P (SP) in aggression; however, the neural circuit mechanisms underlying SP and aggression remain elusive. Here, we show that tachykinin-expressing neurons in the medial amygdala (MeATac1 neurons) are activated during aggressive behaviors in male mice. We identified MeATac1 neurons as a key mediator of aggression and found that MeATac1âventrolateral part of the ventromedial hypothalamic nucleus (VMHvl) projections are critical to the regulation of aggression. Moreover, SP/neurokinin-1 receptor (NK-1R) signaling in the VMHvl modulates aggressive behaviors in male mice. SP/NK-1R signaling regulates aggression by influencing glutamate transmission in neurons in the VMHvl. In summary, these findings place SP as a key node in aggression circuits.
ABSTRACT
Maintaining genomic stability is a prerequisite for proliferating NPCs to ensure genetic fidelity. Though histone arginine methylation has been shown to play important roles in safeguarding genomic stability, the underlying mechanism during brain development is not fully understood. Protein arginine N-methyltransferase 5 (PRMT5) is a type II protein arginine methyltransferase that plays a role in transcriptional regulation. Here, we identify PRMT5 as a key regulator of DNA repair in response to double-strand breaks (DSBs) during NPC proliferation. Prmt5F/F; Emx1-Cre (cKO-Emx1) mice show a distinctive microcephaly phenotype, with partial loss of the dorsal medial cerebral cortex and complete loss of the corpus callosum and hippocampus. This phenotype is resulted from DSBs accumulation in the medial dorsal cortex followed by cell apoptosis. Both RNA sequencing and in vitro DNA repair analyses reveal that PRMT5 is required for DNA homologous recombination (HR) repair. PRMT5 specifically catalyzes H3R2me2s in proliferating NPCs in the developing mouse brain to enhance HR-related gene expression during DNA repair. Finally, overexpression of BRCA1 significantly rescues DSBs accumulation and cell apoptosis in PRMT5-deficient NSCs. Taken together, our results show that PRMT5 maintains genomic stability by regulating histone arginine methylation in proliferating NPCs.
Subject(s)
Neural Stem Cells , Recombinational DNA Repair , Animals , Mice , Arginine/metabolism , DNA Repair , Genomic Instability , Genomics , Histones/genetics , Histones/metabolism , Neural Stem Cells/metabolism , Protein-Arginine N-Methyltransferases/genetics , Protein-Arginine N-Methyltransferases/metabolismABSTRACT
<p><b>OBJECTIVE</b>To observe clinical characteristics of herb-induced liver injury (HILI).</p><p><b>METHODS</b>General conditions, medical history, clinical manifestations, biochemical indices, prognosis, and Roussed Uclaf Causality Assessment Method (RUCAM) scores were retrospectively analyzed in 595 inpatients at 302 Military Hospital between January 2009 and January 2014.</p><p><b>RESULTS</b>There were 423 cases (accounting for 71.1%) were females with multiple onset age ranging 41 to 50 years old. The median time from starting Chinese herbs to the occurrence of liver injury (LI) was 30 days (15-75 days), and 511 cases (85.9%) were classified as hepatocellular injury. Chinese herbs inducing HILI were mainly used for skin disease (102 cases, 17.1%), osteoarticular disease (57 cases, 9.6%), and gastrointestinal disease (49 cases, 8.2%), covering 207 kinds of Chinese patent medicines. Polygonum multiflorum, Psoralea corylifolia, and Corydalis ambigua were often seen in Chinese prescriptions. In RUCAM scoring, 451 HILI patients (accounting for 74.1%) were very possibly associated with Chinese herbs. Liver failure occurred in 47 HILI patients (accounting for 7.9%), cirrhosis in 45 patients (accounting for 7.6%), chronic HILI in 80 patients (accounting for 13.4%), 27 (4.5%) died, and only 2 (0.3%) underwent liver transplantation.</p><p><b>CONCLUSIONS</b>Chinese herbs could cause LI or even death. Attention should be paid to herbal hepatotoxicity and improving monitoring system of HILI.</p>