ABSTRACT
Objective:To explore the impact of the expression of long noncoding RNA-nuclear-enriched abundant transcript 1 (NEAT1) on neurological function and neuronal apoptosis after traumatic brain injury (TBI) in mice and the possible mechanism.Methods:According to the random number table, 90 C57BL/6J mice were divided into sham group, blank control group, empty virus group 1, empty virus group 2, NEAT1 over-expression group and NEAT1 knockdown group, with 15 mice per group. The traumatic brain injury (TBI) was simulated by controlled cortical injury (CCI) model, and NEAT1 was regulated by intracerebroventricular injection with recombinant adenovirus. The neurological severity score (NSS) and Morris water maze test were used to evaluate the neurological function in blank control group, NEAT1 over-expression group and NEAT1 knockdown group within 1 week and 14-21 days after injury. The Western blot was used to observe the expressions of P53-induced protein with a death domain 1 (Pidd1), caspase-2, caspase-9 and caspase-3 in blank control group at 6 hour and 1, 3, 7 days after injury. The TUNEL method and immunofluorescence were used to observe the neurological apoptosis and expression of Pidd1 in blank control group, NEAT1 over-expression group and NEAT1 knockdown group at 3 days after injury. The Western blot analysis was used to detect protein expressions of Pidd1, caspase-2, cytochrome c (Cyt c) and caspase-3 in sham group, blank control group, empty virus groups, NEAT1 over-expression group and NEAT1 knockdown group at 3 days after injury.Results:The NSS was significantly reduced in NEAT1 over-expression group [(3.5±0.7)points], and was significantly increased in NEAT1 knockdown group [(5.0±1.5)points]at day 1 after injury, when compared with blank control group [(4.9±1.0)points]( P<0.01). The Morris water maze test showed that the time to find platform was decreased in NEAT1 over-expression group[(10.9±2.8)seconds], and was prolonged in NEAT1 knockdown group [(30.7±6.2)seconds] at day 19 after injury ( P<0.05 or 0.01), when compared with blank control group [(20.1±5.6)seconds]. The Western blot analysis showed that the expressions of Pidd1, caspase-2, caspase-9 and caspase-3 had significant increase at day 3 after injury ( P<0.01). The TUNEL test showed that the apoptosis rate of neurons was significantly decreased in NEAT1 over-expression group [(18.0±2.7)%], and the apoptosis rate was significantly increased in NEAT1 knockdown group [(63.0±8.6)%] at day 3 after injury ( P<0.01). Immunofluorescence showed that the expression of Pidd1 protein in cytoplasm of the neurons was decreased in NEAT1 over-expression group [(22.7±2.2)%]( P<0.01), and was increased in NEAT1 knockdown group [(72.7±7.0)%]( P<0.01) at day 3 after injury, when compared with blank control group. The Western blot analysis showed that the expressions of Pidd1, capsase-2, Cyt c and caspase-3 were significantly reduced in NEAT1 over-expression group (0.5±0.0, 0.3±0.0, 0.5±0.0, 0.4±0.0) at day 3 after injury, when compared with blank control group. However, the results were opposite in NEAT1 knockdown group. Conclusion:After TBI, the NEAT1 can reduce the activation of caspase-3 through the Pidd1-caspase-2-Cyt c pathway after TBI, regulate neuronal apoptosis, and ultimately play a protective role in neurological function.
ABSTRACT
Background@#Accumulating documents have demonstrated that long noncoding RNAs (lncRNAs) play critical roles in tumorigenesis. As an lncRNA, nuclear-enriched abundant transcript 1 (NEAT1) has been identified to be involved in the progression of many types of cancers. However, the biological function of NEAT1 in cervical cancer is not fully investigated. The aim of this study was to disclose the specific biological function of lncRNA NEAT1 in cervical cancer progression.@*Methods@#Quantitative real-time polymerase chain reaction (qRT-PCR) was utilized to identify the expression of lncRNA NEAT1 in the cervical cancer tissues and cell lines. All cervical cancer samples used in this study were collected from the Affiliated Suzhou Hospital of Nanjing Medical University between September 2012 and September 2017. The correlation between NEAT1 expression and the overall survival rate of cervical cancer patients was analyzed by Kaplan-Meier analysis. The effects of NEAT1 knockdown or overexpression on cell proliferation were tested by performing MTT assays and colony formation assays. Transwell assays were conducted to detect the migratory ability of cervical cancer cells, in which NEAT1 was silenced or overexpressed. Western blotting was utilized to validate whether NEAT1 promotes cervical cancer progression through activating PI3K-Akt signaling pathway.@*Results@#High expression of NEAT1 predicted poor prognosis of cervical cancer patients (χ = 0.735, P = 0.005). Knockdown of NEAT1 decreased the number of colonies in CaSki cell from 136.667 ± 13.503 to 71.667 ± 7.506 (t = -18.76, P = 0.003) and decreased the number of colonies in HeLa cell from 128.667 ± 13.317 to 65.667 ± 7.024 (t = -5.54, P = 0.031). However, overexpression of NEAT1 increased the number of colonies in SiHa cell from 84.667 ± 12.014 to 150.667 ± 18.037 (t = 7.27, P = 0.018). Knockdown of NEAT1 decreased the migratory number of CaSki cell from 100.333 ± 9.866 to 58.333 ± 5.859 (t = -8.08, P = 0.015) and reduced the migratory number in HeLa cell from 123.667 ± 12.097 to 67.667 ± 7.095 (t = -6.03, P = 0.026). Overexpression of NEAT1 increased the migratory number of SiHa cell from 127.333 ± 16.042 to 231.333 ± 31.786 (t = 4.92, P = 0.039).@*Conclusion@#NEAT1 may exert oncogenic function in cervical cancer and serve as a novel therapeutic target for cervical cancer.