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Surface oxidation, as one of fundamental chemical reactions in metals, greatly affects their properties. Herein, we develop a new quaternary GaInSnZn liquid metal with the melting temperature of 9.7 °C, which is the lowest among all reported Ga-based liquid metals. With high-resolution transmission electron microscopy, we directly observed the oxide layer formed on the surface of the liquid metal. The initially formed oxide layer is revealed to be amorphous and very sensitive to electron beam. Prolonged irradiation results in its structural change from amorphous to crystalline phases. The present finding refreshes the basic understanding of surface oxidization of liquid metals and opens up the possibility of tuning surface structures and morphologies by using electron beam irradiation.

Mechanisms underlying motor neuron degeneration in amyotrophic lateral sclerosis (ALS) are yet unclear. Specific deletion of the ER-component membralin in astrocytes manifested postnatal motor defects and lethality in mice, causing the accumulation of extracellular glutamate through reducing the glutamate transporter EAAT2. Restoring EAAT2 levels in membralin KO astrocytes limited astrocyte-dependent excitotoxicity in motor neurons. Transcriptomic profiles from mouse astrocytic membralin KO motor cortex indicated significant perturbation in KEGG pathway components related to ALS, including downregulation of Eaat2 and upregulation of Tnfrsf1a. Changes in gene expression with membralin deletion also overlapped with mouse ALS models and reactive astrocytes. Our results shown that activation of TNF receptor (TNFR1)-NFκB pathway known to suppress Eaat2 transcription was upregulated with membralin deletion. Further, reduced membralin and EAAT2 levels correlated with disease progression in spinal cord from SOD1-mutant mouse models, and reductions in membralin/EAAT2 were observed in human ALS spinal cord. Importantly, overexpression of membralin in SOD1G93A astrocytes decreased TNFR1 levels and increased EAAT2 expression, and improved motor neuron survival. Importantly, upregulation of membralin in SOD1G93A mice significantly prolonged mouse survival. Together, our study provided a mechanism for ALS pathogenesis where membralin limited glutamatergic neurotoxicity, suggesting that modulating membralin had potentials in ALS therapy.

Arecoline, the predominant bioactive substance extracted from areca nut (AN), is the world's fourth most frequently used psychoactive material. Research has revealed that chewing AN can affect the central nervous system (CNS) and may lead to neurocognitive deficits that are possibly linked to the action of arecoline. However, the mechanism behind the neurotoxicity caused by arecoline remains unclear. This study aimed to investigate the neurotoxic effects of arecoline and its underlying mechanism. The results showed that arecoline caused cytotoxicity against HT22 cells in a dose‐dependent manner and induced apoptosis by upregulating the expression of pro‐apoptotic caspase and Bcl‐2 family proteins. Furthermore, arecoline escalated intracellular reactive oxygen species (ROS) levels and Ca2+ concentration with increasing doses, thereby motivating endoplasmic reticulum stress (ERS) and ERS‐associated apoptotic protein expression. Additionally, the study found that arecoline attenuates intracellular antioxidant defense by inhibiting the translocation of NF‐E2‐related factor‐2 (Nrf2) into the nucleus and decreasing downstream Heme oxygenase‐1 (HO‐1) levels. The specific inhibitor Sodium 4‐phenylbutyrate (4‐PBA) can dramatically attenuate arecoline‐mediated cell apoptosis and ERS‐associated apoptotic pathway expression by blocking ERS. The antioxidant N‐Acetylcysteine (NAC) also effectively reverses the arecoline‐mediated increase of ERS‐related apoptotic pathway protein levels by scavenging intracellular ROS accumulation. In conclusion, this study suggests that arecoline induces neurotoxicity in HT22 cells via ERS mediated by oxidative stress‐ and Ca2+ disturbance, as well as by downregulation of the Nrf2/HO‐1 pathway. [ABSTRACT FROM AUTHOR]

Methamphetamine (METH) abuse is frequent in individuals infected with human immunodeficiency virus type-1 (HIV-1) and is suspected to aggravate HIV-associated neurocognitive disorders (HAND). METH is a psychostimulant that compromises several neurotransmitter systems and HIV proteins trigger neuronal injury but the combined effects of viral infection and METH abuse are incompletely understood. In this study we treated transgenic mice expressing the HIV envelope protein gp120 in the brain (HIV-1 gp120tg) at 3-4 months of age with an escalating-dose, multiple-binge METH regimen. The long-term effects were analyzed after 6-7 months of drug abstinence employing behavioral tests and analysis of neuropathology, electrophysiology and gene expression. Behavioral testing showed that both HIV-1 gp120tg and WT animals treated with METH displayed impaired learning and memory. Neuropathological analysis revealed that METH similar to HIV-1 gp120 caused a significant loss of neuronal dendrites and pre-synaptic terminals in hippocampus and cerebral cortex of WT animals. Electrophysiological studies in hippocampal slices showed that METH exposed HIV-1 gp120tg animals displayed reduced post-tetanic potentiation, whereas both gp120 expression and METH lead to reduced long-term potentiation. A quantitative reverse transcription-polymerase chain reaction array showed that gp120 expression, METH and their combination each caused a significant dysregulation of specific components of GABAergic and glutamatergic neurotransmission systems, providing a possible mechanism for synaptic dysfunction and behavioral impairment. In conclusion, both HIV-1 gp120 and METH caused lasting behavioral impairment in association with neuropathology and altered gene expression. However, combined METH exposure and HIV-1 gp120 expression resulted in the most pronounced, long lasting pre- and post-synaptic alterations coinciding with impaired learning and memory.

Abstract K+ channel interacting protein 1 (KChIP1) is a neuronal calcium sensor (NCS) protein that interacts with multiple intracellular molecules. Its physiological function, however, remains largely unknown. We report that KChIP1 is predominantly expressed at GABAergic synapses of a subset of parvalbumin-positive neurons in the brain. Forced expression of KChIP1 in cultured hippocampal neurons increased the frequency of miniature inhibitory postsynaptic currents (mIPSCs), reduced paired pulse facilitation of autaptic IPSCs, and decreases potassium current density. Furthermore, genetic ablation of KChIP1 potentiated potassium current density in neurons and caused a robust enhancement of anxiety-like behavior in mice. Our study suggests that KChIP1 is a synaptic protein that regulates behavioral anxiety by modulating inhibitory synaptic transmission, and drugs that act on KChIP1 may help to treat patients with mood disorders including anxiety.

Huntington's disease is caused by an expanded CAG repeat in the gene encoding huntingtin (HTT), resulting in loss of striatal and cortical neurons. Given that the gene product is widely expressed, it remains unclear why neurons are selectively targeted. Here we show the relationship between synaptic and extrasynaptic activity, inclusion formation of mutant huntingtin protein (mtHtt) and neuronal survival. Synaptic N-methyl-D-aspartate-type glutamate receptor (NMDAR) activity induces mtHtt inclusions via a T complex-1 (TCP-1) ring complex (TRiC)-dependent mechanism, rendering neurons more resistant to mtHtt-mediated cell death. In contrast, stimulation of extrasynaptic NMDARs increases the vulnerability of mtHtt-containing neurons to cell death by impairing the neuroprotective cyclic AMP response element-binding protein (CREB)-peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha) cascade and increasing the level of the small guanine nucleotide-binding protein Rhes, which is known to sumoylate and disaggregate mtHtt. Treatment of transgenic mice expressing a yeast artificial chromosome containing 128 CAG repeats (YAC128) with low-dose memantine blocks extrasynaptic (but not synaptic) NMDARs and ameliorates neuropathological and behavioral manifestations. By contrast, high-dose memantine, which blocks both extrasynaptic and synaptic NMDAR activity, decreases neuronal inclusions and worsens these outcomes. Our findings offer a rational therapeutic approach for protecting susceptible neurons in Huntington's disease.

AIM: To investigate the effect of melatonin (MEL) on the depression behavior in mice induced by chronic restraint stress (CRS). METHODS: Forty-eight SPF-grade male C57BL/6J mice were randomly divided into control group (;i=12) and CRS group (n-36). The mice in CRS group were further divided into 3 groups (n-12) : CRS+vehicle group, CRS+fluoxetine (FLX) group, and CRS+MEL group. Mouse depression model was established by the CRS method for 14 d, and then the depression-like behaviors were observed for modeling validation. After 14 d of drug intervention combined with CRS, the behaviors were detected again. Nissl staining, RT-qPCR, Western blot and immunofluorescence staining were performed in mouse brain tissues. RESULTS: Compared with control group, the weight changes of the mice in CRS group were significantly lowered, the immobility time of forced swimming and tail suspension tests was significantly increased, the consumption rate of sugar water decreased significantly, and the central time and movement distance in open-field test decreased significantly (P<0.01). Compared with CRS+vehicle group, the depression-like behaviors induced by CRS were successfully reversed by the drugs in both CRS+FLX and CRS+MEL groups. Furthermore, compared with CRS+vehicle group, the mRNA levels of brain-derived neurotrophic factor (BDNF), extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB), and the protein levels of BDNF, phosphorylated ERK1/2 and CREB were increased significantly in both CRS+FLX and CRS+MEL groups (P«X 01). The results of Nissl staining showed that the neurons in CRS+vehicle group were irregularly arranged, and the number of Nissl bodies was decreased (P<0. 01). The neuron status and number of Nissl bodies in both CRS+FLX and CRS+MEL groups were significantly improved (P<0. 01). Immunofluorescence staining showed that the number of c-Fos-positive cells in the frontal cortex and hippocampal CA1 region of the mice in CRS+vehicle group was significantly larger than that in control group (P< 0.01). Conversely, the number of c-Fos-positive cells in CRS+FLX and CRS+MEL groups was significantly smaller than that in CRS+vehicle group (P<0. 01). CONCLUSION: Melatonin can significantly alleviate depression-like behavior induced by CRS in mice, which may be related to the activation of BDNF-ERK-CREB signaling pathway. [ABSTRACT FROM AUTHOR]

KIF4A has been demonstrated to play a crucial function in the pathogenesis of a broad number of tumors and have close association with PI3K/AKT pathway. The aim of this study was to explore the potential function of KIF4A in lung cancer progression by targeting PI3K/AKT pathway and P21 combination with doxorubicin. A549 cell lines were transfected with siRNA against KIF4A and negative control siRNA (si‐NC). MTT assay and trypan blue staining were used to evaluate the effect of si‐KIF4A on the doxorubicin cytotoxicity. The mRNA and protein expression levels of KIF4A and p21 were assessed by qRT‐PCR and Western blotting. Apoptosis was measured by cell death ELISA kit. Our result revealed that KIF4A silencing decreased cellular proliferation in A549 lung cancer cells. Doxorubicin in combination with si‐KIF4A led to significant reduction in the survival rate of A549 cell. KIF4A silencing upregulated p21. In conclusion, our results demonstrate that KIF4A inhibition sensitizes A549 cells to doxorubicin by targeting p21 and PI3K/AKT pathway, indicating a significant role for KIF4A in lung cancer chemotherapy. [ABSTRACT FROM AUTHOR]