YY1/LncRNA GAS5 complex aggravates cerebral ischemia/reperfusion injury through enhancing neuronal glycolysis.

Yin-Yang 1 (YY1) has been identified as playing critical roles in multiple diseases. However, little is known regarding its roles and mechanisms in cerebral ischemia/reperfusion (I/R) injury. This study is aimed to explore the roles of YY1 in regulating neuronal apoptosis in cerebral I/R injury and its underlying mechanisms. Primary mouse cerebral cortical neurons were isolated and subjected to OGD/R to mimic cerebral I/R injury in vitro. The roles of YY1 on OGD/R-induced neuronal injury were investigated by performing western blotting, quantitative real-time polymerase chain reaction, TUNEL, RNA-binding protein immunoprecipitation, chromatin immunoprecipitation, chromatin isolation by RNA purification assay, glucose uptake assay, lactate production assay, and extracellular acidification rate assay. YY1-binding long non-coding RNAs (LncRNAs) in neurons subjected to OGD/R were identified by RIP and RNA sequencing. The roles of YY1 on cerebral I/R in vivo were detected by assessing neuronbehaviour, infarct size, and neuronal apoptosis. We found that YY1 expression is downregulated, and LncRNA GAS5 is upregulated in neurons subjected to OGD/R. OGD/R treatment promotes YY1 interacting with GAS5 in neurons, and YY1 negatively regulates GAS5 expression by binding to GAS5 promoter to repress its transcription. Besides, YY1 and GAS5 bind to the same region of PFKFB3 promoter to promote PFKFB3 expression and strengthen neuronal glycolysis, resulting in aggravating OGD/R-induced neuronal apoptosis. Knockdown of YY1 or GAS5 protects against I/R-induced ischemic brain damage and improves overall neurological functions in vivo. Overall, YY1 interacts with LncRNA GAS5 to promote PFKFB3 transcription to enhance neuronal glycolysis, resulting in aggravating cerebral I/R injury.

YY1 promotes IL-6 expression in LPS-stimulated BV2 microglial cells by interacting with p65 to promote transcriptional activation of IL-6.

Neuroinflammation plays a critical role in the process of neurodegenerative disorders, during which microglia, the principal resident immune cells in the central nervous system, are activated and produce proinflammatory mediators. Yin-Yang 1 (YY1), a multi-functional transcription factor, is widely expressed in cells of the immune system and participate in various cellular processes. However, whether YY1 is involved in the process of neuroinflammation is still unknown. In the present study, we found that YY1 was progressively up-regulated in BV2 microglial cells stimulated with lipopolysaccharide (LPS), which was dependent on the transactivation function of nuclear factor kappa B (NF-κB). Furthermore, YY1 knockdown notably inhibited LPS-induced the activation of NF-κB signaling and interleukin-6 (IL-6) expression in BV-2 cells, but not mitogen-activated protein kinase (MAPK) signaling. Moreover, YY1 strengthened p65 binding to IL-6 promoter by interacting with p65 but decreased H3K27ac modification on IL-6 promoter, eventually increasing IL-6 transcription. Taken together, these results for the first time uncover the regulatory mechanism of YY1 on IL-6 expression during neuroinflammation responses and provide new lights into neuroinflammation.

Curcumin protects neural cells against ischemic injury in N2a cells and mouse brain with ischemic stroke.

Background and Purpose: Curcumin, a natural antioxidant isolated from Curcuma longa, has been reported to exert neuroprotective effect in animal models of ischemic stroke. However, the underlying mechanism is still not fully understood. The purpose of this study was to investigate the effect of curcumin treatment on neuronal apoptosis in the periinfarct cortex after cerebral ischemia/reperfusion (I/R) injury and in mouse N2a cells after oxygen-glucose deprivation/reoxygenation (OGD/R) injury and its underlying mechanism. Methods: The cerebral I/R injury was established by 1-hr middle cerebral artery occlusion (MCAO) and reperfusion in mice. Infarct volume was determined by TTC staining, and neurological score was evaluated by mNSS. Cell morphology in the ischemic boundary zone were detected by HE staining. The number and apoptotic rate of neurons in ischemic boundary zone were assayed by immunohistochemistry and TUNEL, respectively. Mouse neuroblastoma N2a cells were subjected to OGD/R. Cell viability was assessed with CCK-8. The mitochondrial membrane potential was measured using JC-1 staining. The expression of Bax, Bcl-2, and caspase-3 was detected using Western blotting. Besides, cellular distribution of Bax was determined by immunofluorescence assays. Results: Curcumin treatment reduced infarct volume, improved neurological function, alleviated the morphological damage of neurons, and increased neuronal survival rate after I/R injury in vivo. Moreover, curcumin treatment improved cell viability, reduced cell apoptosis, increased Bcl-2 protein levels while decreased Bax and caspase-3 expressions in mouse N2a cells after OGD/R injury. Besides, curcumin treatment inhibited Bax activation and maintained mitochondrial membrane integrity. Conclusion: Curcumin promotes neuron survival in vivo and in vitro to exert neuroprotective effects against ischemia injury. Moreover, our results for the first time demonstrated curcumin inhibited ischemia-induced mitochondrial apoptosis via restricting Bax activation, which may be one of the possible mechanisms underlying the neuroprotective effects of curcumin.

Yin Yang 1 Dynamically Regulates Antiviral Innate Immune Responses During Viral Infection.

BACKGROUND/AIMS: Type I interferon (IFN-1) production and IFN-1 signaling play critical roles in the host antiviral innate immune responses. Although transcription factor Yin Yang 1 (YY1) has been reported to have a dual activator/repressor role during the regulation of interferon beta (IFN-ß) promoter activity, the roles of YY1 in the regulation of upstream signaling pathways leading to IFN-1 induction and IFN-1 signaling during viral infection remain to be elucidated. METHODS: The roles of YY1 in IFN-1 production and IFN-1 signaling were investigated using immunoblotting, real-time PCR, small interfering RNA (siRNA)-mediated YY1 knockdown, YY1 overexpression by transient transfection, and co-immunoprecipitation, using mouse cells. RESULTS: YY1 was shown to interact with STAT1 in the absence of viral infection. Following viral infection, YY1 protein expression levels were decreased. YY1 knockdown led to a considerable downregulation of phosphorylated (p) TBK1 and pIRF3 expressions, while YY1 overexpression significantly upregulated pTBK1 and pIRF3 expression levels and promoted virus-induced IFN-ß production. Additionally, YY1 knockdown led to a significant upregulation of pSTAT1, pSTAT2 and antiviral interferon-stimulated genes, and inhibited viral replication. CONCLUSION: We demonstrated here that YY1 interacts with STAT1 and dynamically regulates the induction of IFN-1 production and activation of IFN-1 signaling in different stages during viral infection.

Quality of life in elderly continuous ambulatory peritoneal dialysis patients.

OBJECTIVE: In the present study, we determined the characteristic of quality of life (QOL) in elderly peritoneal dialysis (PD) patients by using the Medical Outcomes Study Short Form 36 (SF-36) to compare QOL between two age groups of continuous ambulatory PD patients. PATIENTS AND METHODS: Patients were allocated to one of two groups according to age: patients in group A were >or=65 years of age, and patients in group B were <65 years of age. We compared SF-36 scores, serum albumin, prealbumin, hemoglobin, lipid profile, normalized protein catabolic rate (nPCR), dialysis adequacy (Kt/V), creatinine clearance (CCr), and glomerular filtration rate (GFR) between the two groups. RESULTS: Group A contained 25 patients, and group B, 53 patients. Mean age in the two groups was 68.6 +/- 3.3 years and 47.7 +/- 10.2 years respectively. Elderly patients showed lower QOL scores with regard to physical problems. Quality-of-life scores with regard to psychological problems were similar in the two groups. Duration of PD, body mass index, serum albumin, prealbumin, hemoglobin, and lipid profile were not different between the two groups. However, nPCR, GFR, and total solute clearance were lower in group A than in group B (nPCR: 0.70 +/- 0.13 g/kg daily vs 0.95 +/- 0.21 g/kg daily, p < 0.001; GFR: 1.03 +/- 1.21 mL/min vs 3.19 +/- 2.22 mL/min, p < 0.001). CONCLUSIONS: In elderly patients, QOL scores were lower, mainly because of a perception of being more physically impaired. Nutritional indices and QOL scores reflecting psychological processes were similar between the two groups. These descriptive data show that PD is an ideal choice in elderly patients with end-stage renal disease. More attention needs to be paid to "healthy start" dialysis and maintenance of nutritional status in elderly patients because of lower GFR and nPCR.