Application targets of lithium ion batteries (LIBs) are moving from small‐sized mobile devices of information technology to large‐scale electric vehicles (xEVs) and energy storage systems (ESSs). Environmental issues and abruptly increasing power demands are pushing high performance energy storage devices or systems onto markets. LIBs are one of the most potential candidates as the energy storage devices mainly due to their high energy densities with fairly good rate capabilities and a fairly long cycle life. As battery systems become larger in terms of stored energy as well as physical size, the safety concerns should be more seriously cared. Each application target has its own specification so that electrode materials should be chosen to meet requirements of the corresponding application. This report diagnoses the current market trends of LIBs as a primary topic, followed by giving an overview of anode and cathode material candidates of LIBs for xEVs and ESSs based on their electrochemical properties.
BackgroundGlaucoma is a major blinding disease characterized by progressive loss of retinal ganglion cells (RGCs) and axons. Optineurin is one of the candidate genes identified so far. A mutation of Glu50 to Lys (E50K) has been reported to be associated with a more progressive and severe disease. Optineurin, known to interact with Rab8, myosin VI and transferrin receptor (TfR), was speculated to have a role in protein trafficking. Here we determined whether, and how optineurin overexpression and E50K mutation affect the internalization of transferrin (Tf), widely used as a marker for receptor-mediated endocytosis.Methodology/Principal FindingsHuman retinal pigment epithelial (RPE) and rat RGC5 cells transfected to overexpress wild type optineurin were incubated with Texas Red-Tf to evaluate Tf uptake. Granular structures or dots referred to as foci formed in perinuclear regions after transfection. An impairment of the Tf uptake was in addition observed in transfected cells. Compared to overexpression of the wild type, E50K mutation yielded an increased foci formation and a more pronounced defect in Tf uptake. Co-transfection with TfR, but not Rab8 or myosin VI, construct rescued the optineurin inhibitory effect, suggesting that TfR was the factor involved in the trafficking phenotype. Forced expression of both wild type and E50K optineurin rendered TfR to colocalize with the foci. Surface biotinylation experiments showed that the surface level of TfR was also reduced, leading presumably to an impeded Tf uptake. A non-consequential Leu157 to Ala (L157A) mutation that displayed much reduced foci formation and TfR binding had normal TfR distribution, normal surface TfR level and normal Tf internalization.Conclusions/SignificanceThe present study demonstrates that overexpression of wild type optineurin results in impairment of the Tf uptake in RPE and RGC5 cells. The phenotype is related to the optineurin interaction with TfR. Our results further indicate that E50K induces more dramatic effects than the wild type optineurin, and is thus a gain-of-function mutation. The defective protein trafficking may be one of the underlying bases why glaucoma pathology develops in patients with E50K mutation.
Optineurin is a gene linked to amyotrophic lateral sclerosis, Paget disease of bone, and glaucoma, a major blinding disease. Mutations such as E50K were identified in glaucoma patients. We investigated herein the involvement of ubiquitin-proteasome pathway (UPP) and autophagy, two major routes for protein clearance, in processing of optineurin in a retinal ganglion cell model line RGC5 and neuronal PC12 cells. It was found that the endogenous optineurin level in neuronal cells was increased by treatment of proteasomal inhibitor but not by autophagic and lysosomal inhibitors. Multiple bands immunoreactive to anti-ubiquitin were seen in the optineurin pulldown, indicating that optineurin was ubiquitinated. In cells overexpressing wild type and E50K optineurin, the level of the proteasome regulatory 5 subunit (PSMB5, indicative of proteasome activity) was reduced, whereas that for autophagy marker microtubule-associated protein 1 light chain 3 was enhanced compared with controls. Autophagosome formation was detected by electron microscopy. The foci formed after optineurin transfection were increased upon treatment of an autophagic inhibitor but were decreased by treatment of an inducer, rapamycin. Moreover, the level of optineurin-triggered apoptosis was reduced by rapamycin. This study thus provides compelling evidence that in a normal homeostatic situation, the turnover of endogenous optineurin involves mainly UPP. When optineurin is up-regulated or mutated, the UPP function is compromised, and autophagy comes into play. A decreased PSMB5 level and an induced autophagy were also demonstrated in vivo in retinal ganglion cells of E50K transgenic mice, validating and making relevant the in vitro findings.
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