Ablation of Shank1 Protects against 6-OHDA-induced Cytotoxicity via PRDX3-mediated Inhibition of ER Stress in SN4741 Cells.

BACKGROUND: Postsynaptic density (PSD) is an electron-dense structure that contains various scaffolding and signaling proteins. Shank1 is a master regulator of the synaptic scaffold located at glutamatergic synapses, and has been proposed to be involved in multiple neurological disorders. METHODS: In this study, we investigated the role of shank1 in an in vitro Parkinson's disease (PD) model mimicked by 6-OHDA treatment in neuronal SN4741 cells. The expression of related molecules was detected by western blot and immunostaining. RESULTS: We found that 6-OHDA significantly increased the mRNA and protein levels of shank1 in SN4741 cells, but the subcellular distribution was not altered. Knockdown of shank1 via small interfering RNA (siRNA) protected against 6-OHDA treatment, as evidenced by reduced lactate dehydrogenase (LDH) release and decreased apoptosis. The results of RT-PCR and western blot showed that knockdown of shank1 markedly inhibited the activation of endoplasmic reticulum (ER) stress associated factors after 6-OHDA exposure. In addition, the downregulation of shank1 obviously increased the expression of PRDX3, which was accompanied by the preservation of mitochondrial function. Mechanically, downregulation of PRDX3 via siRNA partially prevented the shank1 knockdowninduced protection against 6-OHDA in SN4741 cells. CONCLUSION: In summary, the present study has provided the first evidence that the knockdown of shank1 protects against 6-OHDA-induced ER stress and mitochondrial dysfunction through activating the PRDX3 pathway.

Arc regulates brain damage and neuroinflammation via Sirt1 signaling following subarachnoid hemorrhage.

Aneurysmal subarachnoid hemorrhage (aSAH) accounts for only 5 % of all stroke cases, but carries a heavy burden of morbidity and mortality. Activity regulated cytoskeleton associated protein (Arc) is an immediate early gene (IEG)-coded postsynaptic protein that is involved in synaptic plasticity. Increasing evidence and our previous studies have shown that Arc might be involved in the pathological mechanism of various neurological diseases, such as traumatic brain injury (TBI). In this study, we investigated the level of Arc in cerebrospinal fluids (CSF) of aSAH patients and its potential role in brain damage following experimental SAH model. We found that the levels of Arc in aSAH patients' CSF positively correlated with Hunt-Hess (H&H) grades. Knockdown of endogenous Arc expression by small interfere RNA (siRNA) significantly increased brain edema and oxidative stress following SAH. The results of immunostaining in brain sections showed that knockdown of Arc enhanced activation of microglia and astrocytes. In congruent, generation of inflammatory cytokines following SAH was increased by Si-Arc transfection. The results of western blot analysis showed that knockdown of Arc inhibited the expression of Sirt1 and Nrf2, which was accompanied by decreased enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-px). In addition, activation of sirtuin 1 (Sirt1) via agonist SRT2104 markedly decreased the brain damage and neuroinflammation induced by Arc knockdown. In conclusion, knockdown of endogenous Arc could aggravate brain damage and neuroinflammation following experimental SAH, and Arc levels in aSAH patients' CSF might be a potential indicator of brain damage and prognosis.

Sleep deprivation aggravates brain injury after experimental subarachnoid hemorrhage via TLR4-MyD88 pathway.

Subarachnoid hemorrhage (SAH) is a life-threatening cerebrovascular disease, and most of the SAH patients experience sleep deprivation during their hospital stay. It is well-known that sleep deprivation is one of the key components of developing several neurological disorders, but its effect on brain damage after SAH has not been determined. Therefore, this study was designed to evaluate the effect of sleep deprivation using an experimental SAH model in rats. Induction of sleep deprivation for 24 h aggravated the SAH-induced brain damage, as evidenced by brain edema, neuronal apoptosis and activation of caspase-3. Sleep deprivation also worsened the neurological impairment and cognitive deficits after SAH. The results of immunostaining and western blot showed that sleep deprivation increased the activation of microglial cells. In addition, sleep deprivation differently regulated the expression of anti-inflammatory and pro-inflammatory cytokines. The results of immunofluorescence staining and western blot showed that sleep deprivation markedly increased the activation of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response protein 88 (MyD88). Mechanically, treatment with the TLR4 inhibitor TAK-242 or the MyD88 inhibitor ST2825 significantly attenuated the brain damage and neuroinflammation induced by sleep deprivation after SAH. In conclusion, our results indicate that sleep deprivation aggravates brain damage and neurological dysfunction following experimental SAH in rats. These effects were mediated by the activation of the TLR4-MyD88 cascades and regulation of neuroinflammation.

NDRG2 attenuates ischemia-induced astrocyte necroptosis via the repression of RIPK1.

Cerebral ischemia results in severe brain damage, and is a leading cause of death and long-term disability. Previous studies have investigated methods to activate astrocytes in order to promote repair in injured brain tissue and inhibit cell death. It has previously been shown that N-myc downstream-regulated gene 2 (NDRG2) was highly expressed in astrocytes and associated with cell activity, but the underlying mechanism is largely unknown. The present study generated NDRG2 conditional knockout (Ndrg2-/-) mice to investigate whether NDRG2 can block ischemia-induced astrocyte necroptosis by suppressing receptor interacting protein kinase 1 (RIPK1) expression. This study investigated astrocyte activity in cerebral ischemia, and identified that ischemic brain injuries could trigger RIP-dependent astrocyte necroptosis. The depletion of NDRG2 was found to accelerate permanent middle cerebral artery occlusion-induced necroptosis in the brain tissue of Ndrg2-/- mice, indicating that NDRG2 may act as a neuroprotector during cerebral ischemic injury. The present study suggested that NDRG2 attenuated astrocytic cell death via the suppression of RIPK1. The pharmacological inhibition of astrocyte necroptosis by necrostatin-1 provided neuroprotection against ischemic brain injuries after NDRG2 knockdown. Therefore, NDRG2 could be considered as a potential target for the treatment of cerebral ischemia.

Solid-phase extraction for selective determination of bisphenol A in drinks and fruits by dummy surface molecularly imprinted polymer with direct synthetic method.

A reliable and selective method was developed for the determination of bisphenol A (BPA) in drinks and fruit using dummy surface molecularly imprinted polymer (DSMIP) as a solid-phase extraction (SPE)-enrichment and separation sorbent coupled with high-performance liquid chromatography (HPLC). Tetrabromobisphenol A (TBBPA), whose structure is similar to BPA, was selected as a dummy template molecule. DSMIP has a higher selectivity for BPA than surface non-imprinted polymer (SNIP) when used as sorbents for SPE. Potential factors affecting the extraction efficiency, including conditioning, sample loading, washing and elution, and the breakthrough volume were optimised. Under the optimum experimental conditions, the recoveries of BPA in drinks and fruit were in the range from 98% to 105% with relative standard deviations (RSDs) below 7%, and a limit of detection (LOD) of 3 ng ml(-1). The developed extraction protocol eliminated the effect of template leakage on quantitative analysis and could be applied to the trace determination of BPA in complicated functional samples.