FUS-induced neurotoxicity is prevented by inhibiting GSK-3ß in a Drosophila model of amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS)-linked mutations in fused in sarcoma (FUS) lead to the formation of cytoplasmic aggregates in neurons. They are believed to play a critical role in the pathogenesis of FUS-associated ALS. Therefore, the clearance and degradation of cytoplasmic FUS aggregates in neurons may be considered a therapeutic strategy for ALS. However, the molecular pathogenic mechanisms behind FUS-associated ALS remain poorly understood. Here, we report GSK-3ß as a potential modulator of FUS-induced toxicity. We demonstrated that RNAi-mediated knockdown of Drosophila ortholog Shaggy in FUS-expressing flies suppresses defective phenotypes, including retinal degeneration, motor defects, motor neuron degeneration and mitochondrial dysfunction. Furthermore, we found that cytoplasmic FUS aggregates were significantly reduced by Shaggy knockdown. In addition, we found that the levels of FUS proteins were significantly reduced by co-overexpression of Slimb, a F-box protein, in FUS-expressing flies, indicating that Slimb is critical for the suppressive effect of Shaggy/GSK-3ß inhibition on FUS-induced toxicity in Drosophila. These findings revealed a novel mechanism of neuronal protective effect through SCFSlimb-mediated FUS degradation via GSK-3ß inhibition, and provided in vivo evidence of the potential for modulating FUS-induced ALS progression using GSK-3ß inhibitors.

SCF-Slimb is critical for Glycogen synthase kinase-3ß-mediated suppression of TAF15-induced neurotoxicity in Drosophila.

Amyotrophic lateral sclerosis (ALS) is a severe neurodegenerative disorder characterized pathologically by motor neuron degeneration and associated with aggregation of RNA-binding proteins. TATA-binding protein-associated factor 15 (TAF15) accumulates as cytoplasmic aggregates in neuronal cells, and clearance of these aggregates is considered a potential therapeutic strategy for ALS. However, the exact pathogenic mechanism of TAF15-induced neurotoxicity remains to be elucidated. Glycogen synthase kinase-3 (GSK-3) plays a critical role in the protection of ALS pathology. In the present study, we use a transgenic fly model over-expressing human TAF15 to study the protective effects of Shaggy/GSK3ß on TAF15-induced neuronal toxicity in Drosophila brain. Transgenic flies were examined for locomotor activity and lithium treatment. The expression level and solubility of TAF15 were assessed with western blotting, whereas immunohistochemistry was used to assess TAF15 aggregation in Drosophila brain. We have revealed that Shaggy/GSK3ß was abnormally activated in neurons of TAF15-expressing flies and its inhibition can suppress the defective phenotypes, thereby preventing retinal degeneration and locomotive activity caused by TAF15. We have also found that Shaggy/GSK3ß inhibition in neuronal cells leads to a reduction in TAF15 levels. Indeed, the F-box proteins Slimb and archipelago genetically interact with TAF15 and control TAF15 protein level in Drosophila. Importantly, SCFslimb is a critical regulator for Shaggy/GSK3ß-mediated suppression of TAF15-induced toxicity in Drosophila. The present study has provided an in vivo evidence supporting the molecular mechanism of GSK3ß inhibition for protection against TAF15-linked proteinopathies.

Analysis of two quorum sensing-deficient isolates of Pseudomonas aeruginosa.

Three strains of Pseudomonas aeruginosa were isolated: wild-type (WT, NO4) showed normal quorum sensing (QS), whereas QSD3 and QSD7 were QS-deficient (QSD) containing limited N-butyryl homoserine lactone (C4-HSL). The autoinducer activity produced by NO4 was found to be at least 50-fold higher than those by the QSD3 and the QSD7 strains. The QSDs produced lower levels of phenazine compounds (pyocyanin), siderophores (pyoverdine) and biosurfactants (rhamnolipids) than NO4. Therefore, the swarming motility and the swimming motility of the QSD3 and the QSD7 strains also decreased. Treatment with exogenous C4-HSL completely restored rhamnolipid production in both QSDs, suggesting that the biosynthesis of C4-HSL is defective. However, the biofilm production of the QSDs reached much higher levels than those of wild-types (NO4 and P. aeruginosa PAO1). And both QSD strains were more resistant than wild-type cell (NO4) against kanamycin and tobramycin. The RpoS gene, which function is related with QS, is point-nonsense mutated in QSD3 strain. But eleven QS-related genes in QSD3 were not mutated, compared to those of PAO1, which carries intact QS genes and is used as a positive control. This study is helpful in the development of novel approaches in the treatment of P. aeruginosa infections.

Superoxide serves as a putative signal molecule for plant cell division: overexpression of CaRLK1 promotes the plant cell cycle via accumulation of O2- and decrease in H2 O2.

Reactive oxygen species (ROS) exert both positive and negative effects on plant growth and development and therefore receive a great deal of attention in current research. A hot pepper, Capsicum annuum receptor-like kinase 1 (CaRLK1) was ectopically expressed in Nicotiana tabacum BY-2 cell and Nicotiana benthamiana plants. This ectopic expression of CaRLK1 enhanced cell division and proliferation in both heterologous systems. Apparently, CaRLK1 is involved in controlling the cell cycle, possibly by inducing expressions of cyclin B1, cyclin D3, cyclin-dependent protein kinase 3, condensin complex subunit 2 and anaphase-promoting complex subunit 11 genes. CaRLK1 overexpression also increased transcript accumulation of NADPH oxidase genes, generation of O2- and catalase (CAT) activity/protein levels. In parallel, it decreased cellular H2 O2 levels and cell size. Treatment with Tiron or diphenyleneiodonium (DPI) both decreased the cell division rate and O2- concentrations, but increased cellular H2 O2 levels. Tobacco BY-2 cells overexpressing CaRLK1 were more sensitive to amino-1,2,4-triazole (3-AT), a CAT inhibitor, than control cells, suggesting that the increased H2 O2 levels may not function as a signal for cell division and proliferation. Overexpression of CaRLK1 stimulated progression of the cell cycle from G0 /G1 phase into the S phase. It is concluded that the CaRLK1 protein plays a pivotal role in controlling the level of O2- as signaling molecule which promotes cell division, concomitant with a reduction in H2 O2 by the induction of CAT activity/protein.

Glutathionylation on RNA-binding proteins: a regulator of liquid‒liquid phase separation in the pathogenesis of amyotrophic lateral sclerosis.

RNA-binding proteins (RBPs) containing low-sequence complexity domains mediate the formation of cellular condensates and membrane-less organelles with biological functions via liquid‒liquid phase separation (LLPS). However, the abnormal phase transition of these proteins induces the formation of insoluble aggregates. Aggregates are pathological hallmarks of neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS). The molecular mechanisms underlying aggregate formation by ALS-associated RPBs remain largely unknown. This review highlights emerging studies on various posttranslational modifications (PTMs) related to protein aggregation. We begin with the introduction of several ALS-associated RBPs that form aggregates induced by phase separation. In addition, we highlight our recent discovery of a new PTM involved in the phase transition during the pathogenesis of fused-in-sarcoma (FUS)-associated ALS. We suggest a molecular mechanism through which LLPS mediates glutathionylation in FUS-linked ALS. This review aims to provide a detailed overview of the key molecular mechanisms of LLPS-mediated aggregate formation by PTMs, which will help further the understanding of the pathogenesis and development of ALS therapeutics.

Therapeutic modulation of GSTO activity rescues FUS-associated neurotoxicity via deglutathionylation in ALS disease models.

Fused in sarcoma (FUS) is a DNA/RNA-binding protein that is involved in DNA repair and RNA processing. FUS is associated with neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, the molecular mechanisms underlying FUS-mediated neurodegeneration are largely unknown. Here, using a Drosophila model, we showed that the overexpression of glutathione transferase omega 2 (GstO2) reduces cytoplasmic FUS aggregates and prevents neurodegenerative phenotypes, including neurotoxicity and mitochondrial dysfunction. We found a FUS glutathionylation site at the 447th cysteine residue in the RanBP2-type ZnF domain. The glutathionylation of FUS induces FUS aggregation by promoting phase separation. GstO2 reduced cytoplasmic FUS aggregation by deglutathionylation in Drosophila brains. Moreover, we demonstrated that the overexpression of human GSTO1, the homolog of Drosophila GstO2, attenuates FUS-induced neurotoxicity and cytoplasmic FUS accumulation in mouse neuronal cells. Thus, the modulation of FUS glutathionylation might be a promising therapeutic strategy for FUS-associated neurodegenerative diseases.

Cell-based hardware architecture for full-parallel generation algorithm of digital holograms.

This paper proposes a new hardware architecture to speed-up the digital hologram calculation by parallel computation. To realize it, we modify the computer-generated hologram (CGH) equation and propose a cell-based very large scale integrated circuit architecture. We induce a new equation to calculate the horizontal or vertical hologram pixel values in parallel, after finding the calculation regularity in the horizontal or vertical direction from the basic CGH equation. We also propose the architecture of the computer-generated hologram cell consisting of an initial parameter calculator and update-phase calculators based on the equation, and then implement them in hardware. Modifying the equation could simplify the hardware, and approximating the cosine function could optimize the hardware. In addition, we show the hardware architecture to parallelize the calculation in the horizontal direction by extending computer-generated holograms. In the experiments, we analyze hardware resource usage and the performance-capability characteristics of the look-up table used in the computer-generated hologram cell. These analyses make it possible to select the amount of hardware to the precision of the results. Here, we used the platform from our previous work for the computer-generated hologram kernel and the structure of the processor.

MBTI Personality Types of Korean Cabin Crew in Middle Eastern Airlines, and Their Associations with Cross-Cultural Adjustment Competency, Occupational Competency, Coping Competency, Mental Health, and Turnover Intention.

The purposes of this study were (1) to identify MBTI (Myers-Briggs Type Indicator) personality profiles of Korean cabin crew in Middle Eastern airlines, (2) to determine whether MBTI personality affects their cross-cultural adjustment competency, occupational competency, and coping competency, and (3) to analyze the impact of these variables on their mental health and turnover intention. Furthermore, we verified (4) the moderating effect of cabin crew's previous overseas experience on the relationship between cross-cultural adjustment competency and turnover intention. MBTI-Form M test and a survey questionnaire were distributed to 185 Korean cabin crew members in Middle Eastern airlines, and 172 valid datapoints were used for analysis. It was revealed that the cabin crew members showed significantly different levels of cross-cultural adjustment competency, occupational competency, and coping competency depending on their personality traits. Furthermore, those with higher cross-cultural adjustment competency and stress coping are more likely to have positive mental health, which also had an influence on lowering their turnover intention. Occupational competency had no significant association with mental health; however, it directly affects turnover intention. The findings will contribute not only to career plan guidelines for cabin crew aspirants, but also to airlines' recruitment strategies as well as human resources management in aviation industry.

Dysfunction of Mitochondrial Dynamics in Drosophila Model of Diabetic Nephropathy.

Although mitochondrial dysfunction is associated with the development and progression of diabetic nephropathy (DN), its mechanisms are poorly understood, and it remains debatable whether mitochondrial morphological change is a cause of DN. In this study, a Drosophila DN model was established by treating a chronic high-sucrose diet that exhibits similar phenotypes in animals. Results showed that flies fed a chronic high-sucrose diet exhibited a reduction in lifespan, as well as increased lipid droplets in fat body tissue. Furthermore, the chronic high-sucrose diet effectively induced the morphological abnormalities of nephrocytes in Drosophila. High-sucrose diet induced mitochondria fusion in nephrocytes by increasing Opa1 and Marf expression. These findings establish Drosophila as a useful model for studying novel regulators and molecular mechanisms for imbalanced mitochondrial dynamics in the pathogenesis of DN. Furthermore, understanding the pathology of mitochondrial dysfunction regarding morphological changes in DN would facilitate the development of novel therapeutics.

Effects of Gallotannin-Enriched Extract of Galla Rhois on the Activation of Apoptosis, Cell Cycle Arrest, and Inhibition of Migration Ability in LLC1 Cells and LLC1 Tumors.

Gallotannin (GT) and GT-enriched extracts derived from various sources are reported to have anti-tumor activity in esophageal, colon and prostate tumors, although their anti-tumor effects have not been determined in lung carcinomas. To investigate the anti-tumor activity of GT-enriched extract of galla rhois (GEGR) against lung carcinomas, alterations in the cytotoxicity, apoptosis activation, cell cycle progression, migration ability, tumor growth, histopathological structure, and the regulation of signaling pathways were analyzed in Lewis lung carcinoma (LLC1) cells and LLC1 tumor bearing C57BL/6NKorl mice, after exposure to GEGR. A high concentration of GT (69%) and DPPH scavenging activity (IC50=7.922 µg/ml) was obtained in GEGR. GEGR treatment exerted strong cytotoxicity, cell cycle arrest at the G2/M phase and subsequent activation of apoptosis, as well as inhibitory effects on the MAPK pathway and PI3K/AKT mediated cell migration in LLC1 cells. In the in vivo syngeneic model, exposure to GEGR resulted in suppressed growth of the LLC1 tumors, as well as inhibition of NF-κB signaling and their inflammatory cytokines. Taken together, our results provide novel evidence that exposure to GEGR induces activation of apoptosis, cell cycle arrest, and inhibition of cell migration via suppression of the MAPK, NF-κB and PI3K/AKT signaling pathways in LLC1 cells and the LLC1 syngeneic model.