Mir125b-2 imprinted in human but not mouse brain regulates hippocampal function and circuit in mice.

Genomic imprinting predominantly occurs in the placenta and brain. Few imprinted microRNAs have been identified in the brain, and their functional roles in the brain are not clear. Here we show paternal, but not maternal, expression of MIR125B2 in human but not mouse brain. Moreover, Mir125b-2m-/p- mice showed impaired learning and memory, and anxiety, whose functions were hippocampus-dependent. Hippocampal granule cells from Mir125b-2m-/p- mice displayed increased neuronal excitability, increased excitatory synaptic transmission, and decreased inhibitory synaptic transmission. Glutamate ionotropic receptor NMDA type subunit 2A (Grin2a), a key regulator of synaptic plasticity, was physically bound by miR-125b-2 and upregulated in the hippocampus of Mir125b-2m-/p- mice. Taken together, our findings demonstrate MIR125B2 imprinted in human but not mouse brain, mediated learning, memory, and anxiety, regulated excitability and synaptic transmission in hippocampal granule cells, and affected hippocampal expression of Grin2a. Our work provides functional mechanisms of a species-specific imprinted microRNA in the brain.

Neuronal splicing regulator RBFOX3 mediates seizures via regulating Vamp1 expression preferentially in NPY-expressing GABAergic neurons.

Epilepsy is a common neurological disorder, which has been linked to mutations or deletions of RNA binding protein, fox-1 homolog (Caenorhabditis elegans) 3 (RBFOX3)/NeuN, a neuronal splicing regulator. However, the mechanism of seizure mediation by RBFOX3 remains unknown. Here, we show that mice with deletion of Rbfox3 in gamma-aminobutyric acid (GABA) ergic neurons exhibit spontaneous seizures and high premature mortality due to increased presynaptic release, postsynaptic potential, neuronal excitability, and synaptic transmission in hippocampal dentate gyrus granule cells (DGGCs). Attenuating early excitatory gamma-aminobutyric acid (GABA) action by administering bumetanide, an inhibitor of early GABA depolarization, rescued premature mortality. Rbfox3 deletion reduced hippocampal expression of vesicle-associated membrane protein 1 (VAMP1), a GABAergic neuron-specific presynaptic protein. Postnatal restoration of VAMP1 rescued premature mortality and neuronal excitability in DGGCs. Furthermore, Rbfox3 deletion in GABAergic neurons showed fewer neuropeptide Y (NPY)-expressing GABAergic neurons. In addition, deletion of Rbfox3 in NPY-expressing GABAergic neurons lowered intrinsic excitability and increased seizure susceptibility. Our results establish RBFOX3 as a critical regulator and possible treatment path for epilepsy.

RTL1/PEG11 imprinted in human and mouse brain mediates anxiety-like and social behaviors and regulates neuronal excitability in the locus coeruleus.

RTL1/PEG11, which has been associated with anxiety disorders, is a retrotransposon-derived imprinted gene in the placenta. However, imprinting patterns and functions of RTL1 in the brain have not been well-investigated. We found Rtl1 was paternally, but not maternally, expressed in brain stem, thalamus, and hypothalamus of mice, and imprinting status of RTL1 was maintained in human brain. Paternal Rtl1 knockout (Rtl1m+/p-) mice had higher neonatal death rates due to impaired suckling, and low body weights beginning on embryonic day 16.5. High paternal expression of Rtl1 was detected in the locus coeruleus (LC) and Rtl1m+/p- mice showed an increased delay in time of onset for action potentials and inward currents with decreased neuronal excitability of LC neurons. Importantly, Rtl1m+/p- mice exhibited behaviors associated with anxiety, depression, fear-related learning and memory, social dominance, and low locomotor activity. Taken together, our findings demonstrate RTL1 is imprinted in brain, mediates emotional and social behaviors, and regulates excitability in LC neurons.

Predicting College Students' Adoption of Technology for Self-Directed Learning: A Model Based on the Theory of Planned Behavior With Self-Evaluation as an Intermediate Variable.

Many studies assume a significant relationship between intention and behavior. However, the data do not always support this assumption. This study used a modified version of social cognitive theory with self-evaluations as an intermediate variable to explore and resolve the problems associated with applying the theory of planned behavior to explain students' adoption of technology for self-directed learning. We surveyed 285 college students who enrolled in an e-book publishing course using multifaceted technological learning tools. We found that, as an intermediate variable, self-evaluation enhanced the influence of intentions on behavior and improved the accuracy of predictions of college students' adoption of technology for self-directed learning. Students' attitudes and perceived behavioral control were important factors influencing their adoption of technology for self-directed learning through their effects on intention; subjective norms were not important in this respect.

Amelioration of lipopolysaccharide-induced memory impairment in equilibrative nucleoside transporter-2 knockout mice is accompanied by the changes in glutamatergic pathways.

Neuroinflammation has been implicated in cognitive deficits in neurological and neurodegenerative diseases. Lipopolysaccharide (LPS)-induced neuroinflammation and the breakdown of the blood-brain barrier can be attenuated in mice with equilibrative nucleoside transporter-2 (ENT2/Ent2) deletion. The present study was aimed to investigate the role of ENT2 in cognitive and neuronal functions under physiological and inflammatory conditions, in terms of behavioral performance and synaptic plasticity in saline- and LPS-treated Ent2 knockout (KO) mice and their wild-type (WT) littermate controls. Repeated administrations of LPS significantly impaired spatial memory formation in Morris water maze and hippocampal-dependent long-term potentiation (LTP) in WT mice. The LPS-treated WT mice exhibited significant synaptic and neuronal damage in the hippocampus. Notably, the LPS-induced impairment in spatial memory and LTP performance were attenuated in Ent2 KO mice, along with the preservation of neuronal survival. The beneficial effects were accompanied by the normalization of excessive extracellular glutamate and aberrant downstream signaling of glutamate receptor activation, including the upregulation of phosphorylated p38 mitogen-activated protein kinase and the downregulation of phosphorylated cyclic adenosine monophosphate-response element-binding protein. There was no significant difference in behavioral outcome and all tested parameters between these two genotypes under physiological condition. These results suggest that ENT2 plays an important role in regulating inflammation-associated cognitive decline and neuronal damage.

Crumpling-origami transition for twisting cylindrical shells.

Origami and crumpling are two processes to reduce the size of a membrane. In the shrink-expand process, the crease pattern of the former is ordered and protected by its topological mechanism, while that of the latter is disordered and generated randomly. We observe a morphological transition between origami and crumpling states in a twisted cylindrical shell. By studying the regularity of the crease pattern, acoustic emission, and energetics from experiments and simulations, we develop a model to explain this transition from frustration of geometry that causes breaking of rotational symmetry. In contrast to solving von Kármán-Donnell equations numerically, our model allows derivations of analytic formulas that successfully describe the origami state. When generalized to truncated cones and polygonal cylinders, we explain why multiple and/or reversed crumpling-origami transitions can occur.

Deletion of equilibrative nucleoside transporter-2 protects against lipopolysaccharide-induced neuroinflammation and blood-brain barrier dysfunction in mice.

Neuroinflammation is a common pathological feature of many brain diseases and is a key mediator of blood-brain barrier (BBB) breakdown and neuropathogenesis. Adenosine is an endogenous immunomodulator, whose brain extracellular level is tightly controlled by equilibrative nucleoside transporters-1 (ENT1) and ENT2. This study was aimed to investigate the role of ENTs in the modulation of neuroinflammation and BBB function. The results showed that mRNA level of Ent2 was significantly more abundant than that of Ent1 in the brain (hippocampus, cerebral cortex, striatum, midbrain, and cerebellum) of wild-type (WT) mice. Ent2-/- mice displayed higher extracellular adenosine level in the hippocampus than their littermate controls. Repeated lipopolysaccharide (LPS) treatment induced microglia activation, astrogliosis and upregulation of proinflammatory cytokines, along with aberrant BBB phenotypes (including reduced tight junction protein expression, pericyte loss, and immunoglobulin G extravasation) and neuronal apoptosis in the hippocampus of WT mice. Notably, Ent2-/- mice displayed significant resistance to LPS-induced neuroinflammation, BBB breakdown, and neurotoxicity. These findings suggest that Ent2 is critical for the modulation of brain adenosine tone and deletion of Ent2 confers protection against LPS-induced neuroinflammation and neurovascular-associated injury.

The critical role of Nramp1 in degrading α-synuclein oligomers in microglia under iron overload condition.

Oligomeric α-synuclein is a key mediator in the pathogenesis of Parkinson's disease (PD) and is mainly cleared by autophagy-lysosomal pathway, whose dysfunction results in the accumulation and cell-to-cell transmission of α-synuclein. In this study, concomitant with the accumulation of iron and oligomeric α-synuclein, higher expression of a lysosomal iron transporter, natural resistance-associated macrophage protein-1 (Nramp1), was observed in microglia in post-mortem striatum of sporadic PD patients. Using Nramp1-deficient macrophage (RAW264.7) and microglial (BV-2) cells as in-vitro models, iron exposure significantly reduced the degradation rate of the administered human α-synuclein oligomers, which can be restored by the expression of the wild-type, but not mutant (D543N), Nramp1. Likewise, under iron overload condition, mice with functional Nramp1 (DBA/2 and C57BL/6 congenic mice carrying functional Nramp1) had a better ability to degrade infused human α-synuclein oligomers than mice with nonfunctional Nramp1 (C57BL/6) in the brain and microglia. The interplay between iron and Nramp1 exhibited parallel effects on the clearance of α-synuclein and the activity of lysosomal cathepsin D in vitro and in vivo. Collectively, these findings suggest that the function of Nramp1 contributes to microglial degradation of oligomeric α-synuclein under iron overload condition and may be implicated in the pathogenesis of PD.

Structure-activity relationship study of novel 2-aminobenzofuran derivatives as P-glycoprotein inhibitors.

Treatment of cancer patients with chemotherapeutic drugs is often associated with the occurrence of tumors with a multidrug resistance (MDR). Furthermore, the relation between overexpression of P-glycoprotein (P-gp) and resistant cancers has been well established. In this study, novel 2-aminobenzofuran derivatives were synthesized and tested for their ability to modulate P-gp mediated multidrug resistance (MDR) in vitro. The most potent compound, 43, increased P-gp inhibitory activity at 5 µM by 11.12-fold and was 3.6-fold stronger than verapamil. Furthermore, 43 can sensitize Flp-In™-293/MDR cells toward vincristine, paclitaxel and doxorubicin by 17.95-fold, 13.68-fold and 26.43-fold at 2.5 µM, respectively. 43 also can sensitize the resistant cancer cell line KBvin toward vincristine, paclitaxel and doxorubicin by 246.43-fold, 38.72-fold and 5.16-fold at 2.5 µM, respectively. In conclusion, important aspects for developing potent P-gp inhibitors have been emphasized in this study, providing a starting point for the further structural optimization of P-gp inhibitors.

Synthesis and bioevaluation of novel benzodipyranone derivatives as P-glycoprotein inhibitors for multidrug resistance reversal agents.

Multidrug resistance (MDR) is a phenomenon in which cells become resistant to structurally and mechanistically unrelated drugs, and it is one of the emerging problems in cancer therapy today. The relation between overexpression of the ABC transporter subfamily B member 1 (ABCB1/P-glycoprotein) and resistant cancers has been well characterized. In the present study, we successfully synthesized 52 novel benzodipyranone analogs and evaluated for their P-gp inhibitory activity in a P-gp transfected cell line, ABCB1/Flp-In™-293. Among these derivatives, 5a bearing on the 3-methylphenyl substituent, displayed the most potent P-gp inhibitory activity, which can enable the increase of the intracellular accumulation of P-gp substrate Calcein-AM. 5a exhibited more potency on promoted anticancer drugs cytotoxicity by reversing P-gp-mediated drug resistance in both ABCB1/Flp-In™-293 and KBvin cell lines. In particular, the compound 5a sensitized ABCB1/Flp-In™-293 cells toward paclitaxel, vincristine, and doxorubicin by 16.1, 21.0, and 1.6-fold at 10 µM, respectively. Further, 5a dramatically sensitized the resistant cell line KBvin toward paclitaxel and vincristine by 23.1 and 29.7-fold at 10 µM, respectively. It's possible that its mechanism of MDR inhibition can restore the intracellular accumulation of drugs and eventually chemosensitize cancer cells to anticancer drugs and reduce ABCB1 mRNA expression level.