Pharmacological activation of REV-ERBα represses LPS-induced microglial activation through the NF-κB pathway.

REV-ERBα, the NR1D1 (nuclear receptor subfamily 1, group D, member 1) gene product, is a dominant transcriptional silencer that represses the expression of genes involved in numerous physiological functions, including circadian rhythm, inflammation, and metabolism, and plays a crucial role in maintaining immune functions. Microglia-mediated neuroinflammation is tightly associated with various neurodegenerative diseases and psychiatric disorders. However, the role of REV-ERBα in neuroinflammation is largely unclear. In this study, we investigated whether and how pharmacological activation of REV-ERBα affected lipopolysaccharide (LPS)-induced neuroinflammation in mouse microglia in vitro and in vivo. In BV2 cells or primary mouse cultured microglia, application of REV-ERBα agonist GSK4112 or SR9011 dose-dependently suppressed LPS-induced microglial activation through the nuclear factor kappa B (NF-κB) pathway. In BV2 cells, pretreatment with GSK4112 inhibited LPS-induced phosphorylation of the inhibitor of NF-κB alpha (IκBα) kinase (IκK), thus restraining the phosphorylation and degradation of IκBα, and blocked the nuclear translocation of p65, a NF-κB subunit, thereby suppressing the expression and secretion of the proinflammatory cytokines, such as interleukin 6 (IL-6) and tumor necrosis factor α (TNFα). Moreover, REV-ERBα agonist-induced inhibition on neuroinflammation protected neurons from microglial activation-induced damage, which were also demonstrated in mice with their ventral midbrain microinjected with GSK4112, and then stimulated with LPS. Our results reveal that enhanced REV-ERBα activity suppresses microglial activation through the NF-κB pathway in the central nervous system.

Decompression for Traumatic Thoracic/Thoracolumbar Incomplete Spinal Cord Injury: Application of AO Spine Injury Classification System to Identify the Timing of Operation.

OBJECTIVE: Application of AO spine injury classification system (AOSICS) to identify the timing of operation for different types of traumatic thoracic/thoracolumbar incomplete spinal cord injury (SCI). METHODS: A single-center prospective cohort study was conducted to enroll patients with thoracic/thoracolumbar incomplete SCI from April 2013 to November 2016; they were divided into an early group (<24 hours after SCI) and a late group (24-72 hours after SCI). Each group was divided into A, B, C subgroups according to AOSICS. The primary outcomes were ordinal changes in ASIA Impairment Scale at 12-month follow-up. The secondary outcomes included the Medical outcomes study 36-term short form health survey physical component summary (PCS), complications, mortality, and hospital length of stay (LOS). RESULTS: Seven hundred twenty-one patients with thoracic/thoracolumbar incomplete SCI were included; 335 patients underwent early surgery, and 386 patients underwent delayed surgery. Statistical results included the following comparisons of the early versus late groups: AIS improvement of 1 grade or more (combined groups: P = 0.009, odds ratio [OR] = 1.487; A: P = 0.777, OR = 1.072; B: P = 0.029, OR = 1.701; C: P = 0.007, OR = 1.762), AIS improvement 2 grades or more (combined groups: P = 0.002, OR = 2.471; A: P = 0.189, OR = 3.939; B: P = 0.011, OR = 2.550; C: P = 0.035, OR = 3.964) and PCS (combined groups: P = 0.327; A: P = 0.776; B: P = 0.019; C: P = 0.562). LOS (combined groups: P < 0.0001; A, B and C: P < 0.0001). Complications (combined groups: P = 0.267; A: P = 0.830; B: P = 0.111; C: P = 0.757). CONCLUSIONS: Patients with type-A injuries with incomplete SCI do not have to undergo aggressive early operations. Patients with type-B and type-C injuries should undergo an operation early to achieve better clinical results.

Dendritic cell nuclear protein-1 regulates melatonin biosynthesis by binding to BMAL1 and inhibiting the transcription of N-acetyltransferase in C6 cells.

Dendritic cell nuclear protein-1 (DCNP1) is a protein associated with major depression. In the brains of depression patients, DCNP1 is up-regulated. However, how DCNP1 participates in the pathogenesis of major depression remains unknown. In this study, we first transfected HEK293 cells with EGFP-DCNP1 and demonstrated that the full-length DCNP1 protein was localized in the nucleus, and RRK (the residues 117-119) composed its nuclear localization signal (NLS). An RRK-deletion form of DCNP1 (DCNP1ΔRRK) and truncated form (DCNP11-116), each lacking the RRK residues, did not show the specific nuclear localization like full-length DCNP1 in the cells. A rat glioma cell line C6 can synthesize melatonin, a hormone that plays important roles in both sleep and depression. We then revealed that transfection of C6 cells with full-length DCNP1 but not DCNP1ΔRRK or DCNP11-116 significantly decreased the levels of melatonin. Furthermore, overexpression of full-length DCNP1, but not DCNP1ΔRRK or DCNP11-116, in C6 cells significantly decreased both the mRNA and protein levels of N-acetyltransferase (NAT), a key enzyme in melatonin synthesis. Full-length DCNP1 but not DCNP1ΔRRK or DCNP11-116 was detected to interact with the Nat promoter and inhibited its activity through its E-box motif. Furthermore, full-length DCNP1 but not the mutants interacted with and repressed the transcriptional activity of BMAL1, a transcription factor that transactivates Nat through the E-box motif. In conclusion, we have shown that RRK (the residues 117-119) are the NLS responsible for DCNP1 nuclear localization. Nuclear DCNP1 represses NAT expression and melatonin biosynthesis by interacting with BMAL1 and repressing its transcriptional activity. Our study reveals a connection between the major depression candidate protein DCNP1, circadian system and melatonin biosynthesis, which may contribute to the pathogenesis of depression.