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At least 721 records · Page 40

KPT-330, a potent and selective CRM1 inhibitor, exhibits anti-inflammation effects and protection against sepsis

Highlights: • KPT330 protects against LPS-induced septic mice. • KPT330 exerts anti-inflammation effects. • KPT330 inhibits LPS-induced TNF-α, IL-6 and HMGB1 production. • KPT330 suppresses activation of NF-κB and MAPK p38 signaling. Sepsis, a systemic inflammatory response caused by infection or injury, is still one of the most important causes of death in clinical patients. The ongoing search for the pathogenesis of sepsis and novel therapeutic methods are highly urgent. In this study, we hypothesized that KPT330, a potent and specific small molecule inhibitor of CRM1, could reduce inflammation and attenuate the severity of sepsis. In LPS-induced sepsis model in vivo, administration of KPT330 increased survival rate and ameliorated LPS-induced lung injury, with suppressed levels of TNF-α, IL-6 and HMGB1 in the circulation and decreased macrophage and PMN subpopulations in peritoneal cavity. In vitro investigations showed that KPT330 dose-dependently inhibited LPS-triggered proinflammatory cytokines production including TNF-α, IL-6 and HMGB1 in macrophages. Furthermore, KPT330 treatment significantly suppressed TNF-α and IL-6 mRNA expression and inhibited HMGB1 necleocytoplasmic translocation by inhibiting CRM1 distribution. Moreover, the mechanism analysis demonstrated that KPT330 exerted anti-inflammation effects by inhibiting the production of pro-inflammatory cytokines through suppressing activation of NF-κB and p38 signaling. Thus, pharmacologic stimulation of KPT330 may present a promising therapeutic strategy for sepsis.

60 APPLIED LIFE SCIENCES↗

Human gingival fibroblast feeder cells promote maturation of induced pluripotent stem cells into cardiomyocytes

Highlights: • HGF enhanced cardiac differentiation of iPS cells morphologically. • Contractility of iPS-CMs was significantly greater in the HGF feeder condition. • Amount of exogenous substance was minimum in the differentiation protocol. The use of human induced pluripotent stem (iPS) cells has been investigated in multiple regenerative medicine studies. However, although methods for efficient differentiation of iPS cells into heart tissues have been devised, it remains difficult to obtain cardiac tissue with high contractility. Herein, we established a method for differentiating iPS cells into highly contractile cardiomyocytes (CMs), and demonstrate that the use of human gingival fibroblasts (HGFs) as a feeder cells promotes maturation of iPS-derived CMs (iPS-CMs) in vitro. After CM differentiation of iPS cells, iPS-CMs showed increased mRNA expression of the CM specific maker cardiac troponin T (cTnT) in the absence and presence (on-feeder condition) of cocultured HGFs, and decreased expression of pluripotent markers was observed under both conditions. Protein expression of cTnT was also observed in immunocytochemical analyses, although on-feeder CMs showed comparatively robust sarcomere structure and significantly stronger contractility than feederless cardiomyocytes, suggesting that HGF feeder cells facilitate CM differentiation of iPS cells.

60 APPLIED LIFE SCIENCES↗

Isocitrate dehydrogenase 2 deficiency induces endothelial inflammation via p66sh-mediated mitochondrial oxidative stress

Highlights: • IDH2 deficiency triggers severe mitochondrial dysfunction in HUVECs. • IDH2 deficiency induces endothelial inflammation by the increased mitochondrial ROS and p66shc expression. • p66shc mediated IDH2 deficiency-induced inflammatory molecule expression in HUVECs. Isocitrate dehydrogenase 2 (IDH2) is an essential enzyme in the mitochondrial antioxidant system, which produces nicotinamide adenine dinucleotide phosphate, and thereby defends against oxidative stress. We have shown that IDH2 downregulation results in mitochondrial dysfunction and reactive oxygen species (ROS) generation in mouse endothelial cells. The redox enzyme p66shc is a key factor in regulating the level of ROS in endothelial cells. In this study, we hypothesized that IDH2 knockdown-induced mitochondrial dysfunction stimulates endothelial inflammation, which might be regulated by p66shc-mediated oxidative stress. Our results showed that IDH2 downregulation led to mitochondrial dysfunction by decreasing the expression of mitochondrial oxidative phosphorylation complexes I, II, and IV, reducing oxygen consumption, and depolarizing mitochondrial membrane potential in human umbilical vein endothelial cells (HUVECs). The dysfunction not only increased mitochondrial ROS levels but also activated p66shc expression in HUVECs and IDH2 knockout mice. IDH2 deficiency increased intercellular adhesion molecule (ICAM)-1 expression and mRNA levels of pro-inflammatory cytokines (tumor necrosis factor [TNF]-α, and interleukin [IL]-1β) in HUVECs. The mRNA expression of ICAM-1 in endothelial cells and plasma levels of TNF-α and IL-1β were also markedly elevated in IDH2 knockout mice. However, p66shc knockdown rescued IDH2 deficiency-induced mitochondrial ROS levels, monocyte adhesion, ICAM-1, TNF-α, and IL-1β expression in HUVECs. These findings suggest that IDH2 deficiency induced endothelial inflammation via p66shc-mediated mitochondrial oxidative stress.

60 APPLIED LIFE SCIENCES↗

A negative feedback loop between nuclear factor 90 (NF90) and an anti-oncogenic microRNA, miR-7

Highlights: • miR-7, an anti-oncogenic miRNA, represses NF90 at the mRNA level. • The coding region of the NF90 mRNA is directly targeted by miR-7. • A rise in NF90 is attributed to negative feedback between NF90 and miR-7 in tumors. Alterations in microRNAs (miRNAs) levels deeply correlate with tumorigenesis. However, the molecular mechanism for the regulation of the miRNA production in tumors is not fully understood. We previously reported that downregulation of miR-7, which is an anti-oncogenic miRNA, was caused by overexpression of the nuclear factor 90 (NF90)-nuclear factor 45 (NF45) complex through the binding of double-stranded (ds) RNA-binding proteins to primary miR-7, resulting in promotion of tumorigenesis (Higuchi et al 2016). During this study, we found that the level of NF90 protein was dramatically decreased by overexpression of miR-7. Interestingly, the miR-7-mediated reduction in NF90 family proteins was only observed in NF90 protein, but not in NF110 protein, which is a longer form of the NF90 gene. Luciferase reporter analysis indicated that the overexpression of miR-7 significantly repressed the luciferase activity in the coding region of NF90 mRNA harboring a predicted target sequence of miR-7. The luciferase activity of the reporter vector, which has a mutated miR-7 target site in the coding region, was the same in the control and miR-7 overexpressed cells. Furthermore, the translation of TARGET-tagged NF90 mRNA without the 3′UTR of the NF90 mRNA was inhibited by the overexpression of miR-7. These results imply that miR-7 suppresses NF90 at the protein level through the binding of miR-7 to the complementary site of the seed sequence in the coding region of the NF90 mRNA. We further confirmed increased endogenous NF90 protein levels in SK-N-SH cells transfected with antisense oligonucleotides targeting miR-7, indicating that miR-7-mediated translational repression of NF90 is a physiological event. Taken together with our previous findings (Higuchi et al 2016), it suggests that the level of NF90 is increased by a negative feedback loop between NF90 and miR-7 in tumor tissues under physiological conditions.

60 APPLIED LIFE SCIENCES↗

IL-1β/ATF3-mediated induction of Ski2 expression enhances hepatitis B virus x mRNA degradation

Hepatitis B virus (HBV) -x protein is a transcriptional regulator required for the HBV life cycle. HBx also induces complications in the host such as hepatocellular carcinoma. We previously showed that HBx mRNA is degraded by the Ski2/RNA exosome complex. In the present study, we report the regulation of this system through the control of Ski2 expression. We identified interleukin (IL) -1β as an inducer of expression from the Ski2 promoter. IL-1β induced the expression of ATF3 transcription factor, which in turn binds to cyclic AMP-responsive element sequence in the Ski2 promoter and is responsible for Ski2 promoter induction by IL-1β. We previously reported that Ski2 expression increases HBx mRNA degradation; consistent with those data, we showed here that HBx mRNA is degraded in response to IL-1β treatment. Interestingly, HBx also significantly induced Ski2 expression. To our knowledge, this is the first report to show activation of the Ski2/RNA exosome complex by both the host and HBV. Understanding the regulation of the Ski2/RNA exosome system is expected to facilitate prevention of HBx-mediated complications through targeting the posttranscriptional degradation of HBx mRNA; and will also help shedding a light on the role of RNA decay systems in inflammation.

60 APPLIED LIFE SCIENCES↗

The atherogenic actions of LPC on vascular smooth muscle cells and its LPA receptor mediated mechanism

Lysophosphatidylcholine (LPC) is a bioactive lipid constituent of oxidized low density lipoprotein (ox-LDL). It regulates various cellular functions, including migration of circulating monocytes, expression of endothelial adhesion molecules, proliferation and migration of vascular smooth muscle cells (VSMCs). LPC can also be hydrolyzed into lysophosphatidic acid (LPA) by autotaxin (ATX) which possesses lysophospholipase D (lyso-PLD) activity. The aim of this study was to explore the effects of LPC on proliferation and migration of human artery smooth muscle cells (HASMCs) and the involvement of LPC-ATX-LPA pathway in these processes. In vitro, we found that LPC and LPA stimulated HASMCs proliferation and migration. Knockdown of LPA1 by siRNA and inhibit Gi protein with pertussis toxin (PTX) showed the contrary results. Silencing of LPC receptor genes did not significantly affect the LPC induced proliferation and migration. We detected the higher expressed mRNA and protein of ATX in HASMCs, and measured lyso-PLD activity. In atherosclerotic rabbit model, we observed high LPC level and high lyso-D activity in blood, and high expression of LPA1 in aorta walls. We also found that neointima appeared to be thickened and mRNA expressions of LPA1 appeared to be increased. These results revealed that LPC was converted into LPA by ATX to induce the proliferation and migration in HASMCs through LPA1/Gi/o/MAP Kinase signaling pathway. Our research suggested that LPC-ATX-LPA system contributed to the atherogenic action induced by ox-LDL. LPA1 antagonist may be considered as a potential therapeutic and preventative drug for cardiovascular disease.

60 APPLIED LIFE SCIENCES↗

Targeted deletion of HYBID (hyaluronan binding protein involved in hyaluronan depolymerization/ KIAA1199/CEMIP) decreases dendritic spine density in the dentate gyrus through hyaluronan accumulation

Highlights: • Hyaluronan was accumulated in the dentate gyrus of Hybid KO mice. • Newly born neurons were decreased in the dentate gyrus of Hybid KO mice. • Dendritic spine density were decreased in the dentate gyrus neuron of Hybid KO mice. HYBID (hyaluronan binding protein involved in hyaluronan [HA] depolymerization, KIAA1199/CEMIP) is a key player in HA depolymerization of the skin fibroblasts, arthritic synovial fibroblasts, and brain. Our previous study demonstrated that Hybid knock-out (KO) mice showed spatial memorial impairment, which is accompanied by the accumulation of high molecular weight HA in the hippocampus. However, the mechanism underlying cognitive impairment by Hybid deficiency remains unclear. In the present study, we examined the HA distribution patterns in the brains of wild-type (WT) and Hybid KO mice by HA staining using HA binding protein, and found that in Hybid KO mice, HA is accumulated and doublecortin-positive immature neurons are significantly decreased in the dentate gyrus of the hippocampus, where Hybid mRNA is highly expressed in WT mice. The Golgi-Cox staining demonstrated that the dendritic spine density is significantly decreased in the dentate gyrus granule cells in Hybid KO mice. These results suggest that Hybid-mediated HA degradation is critical for the synaptic formation process by contributing to cognitive functions, such as learning and memory, in the mouse brain.

60 APPLIED LIFE SCIENCES↗

OCT4 directly regulates stemness and extracellular matrix-related genes in human germ cell tumours

Germ cell tumours (GCTs) are one of the most threatening malignancies in young men and women. Although several reports have suggested the importance of OCT4 in human GCTs, its role has not been clearly investigated on a molecular level. In this study, we revealed GCT-specific direct transcriptional target genes of OCT4. Conditional knockdown of OCT4 in GCT cell lines reduced cell proliferation by affecting both cell cycle and death. Knockdown of OCT4 also reduced stemness of GCTs, as assessed by the expression of other stemness factors, alkaline phosphatase staining, and tumour sphere formation ability. Analysis of whole mRNA expression patterns among GCT cells harbouring endogenous, depleted, and rescued OCT4 revealed 1133 OCT4 target genes in GCT. Combined analysis of both the chromatin binding signature of OCT4 and the genes whose expression levels were changed by OCT4 revealed 258 direct target genes of OCT4 in GCTs. In a similar way, 594 direct target genes in normal embryonic stem cells (ESCs) were identified. Among these two sets of OCT4 direct target genes, 38 genes were common between GCTs and ESCs, most of which were related to regulation of pluripotency, and 220 genes were specific to GCTs, most of which were related to focal adhesion and extracellular matrix organisation. These results provide a molecular basis for how OCT4 regulates GCT stemness and will aid our understanding of the role of OCT4 in other cancers.

60 APPLIED LIFE SCIENCES↗

Leflunomide attenuates oxidative stress in fetal human lung endothelial cells via superoxide dismutase 2 and catalase

Highlights: • Leflunomide decreases oxidative stress in fetal human lung endothelial cells. • Leflunomide induces catalase, NQO1, and SOD2 enzymes in fetal human lung cells. • Leflunomide effects on oxidative stress, catalase, and SOD2 are AhR-independent. • AhR deficiency abrogates leflunomide-mediated induction of NQO1 enzyme. Hyperoxia-induced oxidative stress contributes to the pathogenesis of bronchopulmonary dysplasia (BPD), the most common respiratory morbidity of preterm infants. Importantly, the disease lack specific therapies and is associated with long-term cardio-pulmonary and neurodevelopmental morbidities, signifying the need to discover novel therapies and decrease the disease burden. We and others have demonstrated that leflunomide, a food and drug administration approved drug to treat humans with rheumatoid arthritis, increases the expression of the anti-oxidant enzymes, NAD(P)H quinone dehydrogenase 1 (NQO1), catalase, and superoxide dismutase (SOD). However, whether this drug can decrease oxidative stress in fetal human pulmonary arterial endothelial cells (HPAECs) is unknown. Therefore, we tested the hypothesis that leflunomide will decrease hyperoxia-induced oxidative stress by upregulating these anti-oxidant enzymes in HPAECs. Leflunomide decreased hydrogen peroxide (H{sub 2}O{sub 2}) levels and increased the mRNA and protein levels of catalase, NQO1, and SOD2 in HPAECs at basal conditions. Further, leflunomide-treated cells continued to have decreased H{sub 2}O{sub 2} and increased SOD2 levels upon hyperoxia exposure. Leflunomide did not affect the expression of other anti-oxidant enzymes, including hemoxygenase-1 and SOD1. AhR-knockdown experiments suggested that leflunomide regulated NQO1 levels via AhR-dependent mechanisms and H{sub 2}O{sub 2}, catalase, and SOD2 levels via AhR-independent mechanisms. Collectively, the results support the hypothesis that leflunomide decreases oxidative stress in HPAECs via SOD2-and catalase-dependent, but AhR- and NQO1-independent mechanisms. Our findings indicate that leflunomide is a potential drug for the management of BPD in preterm infants.

60 APPLIED LIFE SCIENCES↗

Role of PKB/SGK-dependent phosphorylation of GSK-3α/β in vascular calcification during cholecalciferol overload in mice

Highlights: • Vascular calcification was blunted in mice with PKB/SGK-resistant Gsk-3α/β. • PKB/SGK-resistant Gsk-3α/β inhibited aortic osteoinduction. • PKB/SGK-resistant Gsk-3α/β blunted Pit1 and Pai1 up-regulation during calcification. • Vascular PKB/SGK-resistant Gsk-3α/β ameliorated aortic ring calcification ex vivo. Medial vascular calcification is a highly regulated process involving osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells. Both, protein kinase B (PKB) and serum- and glucocorticoid-inducible kinase 1 (SGK1) are involved in the intracellular signaling of vascular calcification and both phosphorylate and inactivate glycogen synthase kinase 3 (GSK-3). The present study explored whether PKB/SGK-dependent phosphorylation of GSK-3α/β is involved in vascular calcification. Experiments were performed in Gsk-3α/β double knockin mice lacking functional PKB/SGK phosphorylation sites (gsk-3{sup KI}) and corresponding wild-type mice (gsk-3{sup WT}) following high-dosed cholecalciferol treatment as well as ex vivo in aortic ring explants from gsk-3{sup KI} and gsk-3{sup WT} mice treated without and with phosphate. In gsk-3{sup WT} mice, high-dosed cholecalciferol induced vascular calcification and aortic osteo-/chondrogenic signaling, shown by increased expression of osteogenic markers Msx2, Cbfa1 and tissue-nonspecific alkaline phosphatase (Alpl). All these effects were suppressed in aortic tissue from gsk-3{sup KI} mice. Cholecalciferol decreased aortic Gsk-3α/β phosphorylation (Ser{sup 21/9}) in gsk-3{sup WT} mice, while no phosphorylation was observed in gsk-3{sup KI} mice. Moreover, the mRNA expression of type III sodium-dependent phosphate transporter (Pit1) and plasminogen activator inhibitor 1 (Pai1) was increased following cholecalciferol treatment in aortic tissue of gsk-3{sup WT} mice, effects again blunted in gsk-3{sup KI} mice. In addition, phosphate treatment induced mineral deposition and osteogenic markers expression in aortic ring explants from gsk-3{sup WT} mice, effects reduced in aortic ring explants from gsk-3{sup KI} mice. In conclusion, vascular PKB/SGK-dependent phosphorylation of GSK-3α/β contributes to the osteoinductive signaling leading to vascular calcification.

60 APPLIED LIFE SCIENCES↗

miR-7-5p acts as a tumor suppressor in bladder cancer by regulating the hedgehog pathway factor Gli3

Although important progresses have been made in the diagnosis and treatment of bladder cancer (BCa), the overall survival for patients with advanced BCa remains poor. It is necessary to uncover the molecular mechanism underlying the initiation and progression of bladder cancer. According to previous reports, mircoRNAs (miRNAs) can regulate tumorigenesis by targeting their downstream mRNAs. This study aims to explore and analyze a novel miRNA-mRNA axis which can regulate the progression of bladder cancer. Based on the microarray analysis, 182 mRNAs were found to be upregulated in BCa tissues. Gene oncology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these upregulated mRNAs are related with hedgehog pathway. Gli3, an important factor of hedgehog pathway, belongs to these 182 upregulated mRNAs. Therefore, Gli3 was chosen to do further study. Kaplan-Meier analysis revealed that highly expressed Gli3 predicted unfavorable prognosis for patients with BCa. Results of functional experiments indicated the inhibitory effects of silenced Gli3 on cell proliferation, migration and EMT progress. Mechanically, Gli3 was the target mRNA of miR-7-5p in BCa cells. Finally, rescue assays were performed to validate the specific function of miR-7-5p/Gli3 axis in BCa progression. According to all data, we concluded that miR-7-5p acts as a tumor suppressor in BCa by downregulating Gli3.

60 APPLIED LIFE SCIENCES↗

Conditionally reprogrammed human normal bronchial epithelial cells express comparable levels of cytochromes p450 and are sensitive to BaP induction

Highlights: • Conditionally reprogrammed human normal bronchial epithelial cells can be propagated for a long term in vitro. • Conditionally reprogrammed human normal bronchial epithelial cells maintain normal karyotype and differentiation potential. • Conditionally reprogrammed human normal bronchial epithelial cells express comparable levels of Cytochromes p450 enzymes. • Conditionally reprogrammed human normal bronchial epithelial cells are sensitive to BaP induction. Cytochromes p450 (CYPs) metabolize thousands of endogenous and exogenous chemicals, including toxic compounds and drugs. The primary cells have relative short life span and are not able to sustain levels of metabolic enzymes CYPs expression and activity long enough in vitro. The immortalized cell lines are also not ideal for toxicity testing because of their low levels of CYPs expression. In this study, we established human normal bronchial epithelial cells using conditional reprogramming (CR) technique from three human donors (named as CR-HNBE1-3). These CR cells can proliferate continuously in defined culture system over 50 PDs within 2 months. The CR-HNBE cells exhibited the normal diploid karyotype, normal response to DNA damage and normal differentiation potential under the matrigel 3D culture condition. The CR-HNBE cells express the basal epithelial marker cytokeratin 14 (CK14) and epithelial secretory marker Mucin 5AC. Most importantly, CR-HNBE cells express comparable levels of CYP1B1 and CYP2E1 as those in lung tissue. These CR cells also express comparable mRNA of CYP1A1/CYP1A2, CYP2B6/CYP2C9/CYP2D6 and CYP3A4/CYP3A5 compared to the lung tissue. The basal activity of CYP1A1/CYP1B1 in these CR cells was 3–6 folds higher than that of 16HBE cells (an immortalized cell line widely used in toxicology field). Our data also demonstrated that Benzo(a)pyrene (BaP) induced up to 100 folds of mRNA expression of CYP1A1 or CYP1A2 in CR-HNBE cells. The activity of CYP1A1/CYP1B1 was induced by BaP up to 7–8 folds in CR-HNBE cells, while the activity of CYP1A1/CYP1B1 was induced maximum 2.5 folds in 16HBE cells. Taken together, CR-HNBE cells express comparable levels of CYPs and are sensitive to BaP induction, and will serve a sensitive, physiological and valuable in vitro toxicity testing model. This is the first report that normal human airway cells can be propagated for a long time and maintain comparable levels of CYPs.

60 APPLIED LIFE SCIENCES↗

The ionic liquid 1-octyl-3-methylimidazolium (M8OI) is an activator of the human estrogen receptor alpha

Highlights: • M8OI activates the human ERα and induces TFF1 in MCF7 cells. • M8OI is a super-activator of the mouse ERβ variant 2 receptor. • M8OI does not activate the human ERβ. Recent environmental sampling around a landfill site in the UK demonstrated that unidentified xenoestrogens were present at higher levels than control sites; that these xenoestrogens were capable of super-activating (resisting ligand-dependent antagonism) the murine variant 2 ERβ and that the ionic liquid 1-octyl-3-methylimidazolium chloride (M8OI) was present in some samples. To determine whether M8OI was a contributor to the xenoestrogen pool in the soils, activation of human estrogen receptors by M8OI was examined. M8OI activated the human ERα in MCF7 cells in a dose-response manner. These effects were inhibited by the ER antagonist ICI182780; occurred in the absence of any metabolism of M8OI and were confirmed on examination of ER-dependent induction of trefoil factor 1 mRNA in MCF7 cells. M8OI also super-activated the murine variant 2 ERβ in a murine hepatopancreatobiliary cell line. The human ERβ was not activated by M8OI when expressed in HEK293 cells. These data demonstrate that M8OI is a xenoestrogen capable of activating the human ERα and super-activating the murine variant 2 ERβ.

60 APPLIED LIFE SCIENCES↗

The heterozygous R155C VCP mutation: Toxic in humans! Harmless in mice?

Highlights: • Mutations of the human VCP gene cause several neurodegenerative diseases. • R155C VCP knock-in mice display multiple abnormalities but no typical VCP diseases. • Mutant VCP mRNA levels were markedly increased in man, but decreased in mice. • R155C VCP mRNA species in man and mice have different biological half lifes. Heterozygous missense mutations in the human VCP gene cause inclusion body myopathy associated with Paget disease of bone and fronto-temporal dementia (IBMPFD) and amyotrophic lateral sclerosis (ALS). The exact molecular mechanisms by which VCP mutations cause disease manifestation in different tissues are incompletely understood. In the present study, we report the comprehensive analysis of a newly generated R155C VCP knock-in mouse model, which expresses the ortholog of the second most frequently occurring human pathogenic VCP mutation. Heterozygous R155C VCP knock-in mice showed decreased plasma lactate, serum albumin and total protein concentrations, platelet numbers, and liver to body weight ratios, and increased oxygen consumption and CD8+/Ly6C + T-cell fractions, but none of the typical human IBMPFD or ALS pathologies. Breeding of heterozygous mice did not yield in the generation of homozygous R155C VCP knock-in animals. Immunoblotting showed identical total VCP protein levels in human IBMPFD and murine R155C VCP knock-in tissues as compared to wild-type controls. However, while in human IBMPFD skeletal muscle tissue 70% of the total VCP mRNA was derived from the mutant allele, in R155C VCP knock-in mice only 5% and 7% mutant mRNA were detected in skeletal muscle and brain tissue, respectively. The lack of any obvious IBMPFD or ALS pathology could thus be a consequence of the very low expression of mutant VCP. We conclude that the increased and decreased fractions of the R155C mutant VCP mRNA in man and mice, respectively, are due to missense mutation-induced, divergent alterations in the biological half-life of the human and murine mutant mRNAs. Furthermore, our work suggests that therapy approaches lowering the expression of the mutant VCP mRNA below a critical threshold may ameliorate the intrinsic disease pathology.

60 APPLIED LIFE SCIENCES↗

Staufen1, Kinesin1 and microtubule function in cyclin B1 mRNA transport to the animal polar cytoplasm of zebrafish oocytes

Highlights: • Zebrafish cyclin B1 mRNA is transported to the animal polar cytoplasm of oocytes. • Microtubule, Kinesin1 and Stufen1 are involved in cyclin B1 mRNA transport. • The plus ends of microtubules accumulate to the animal pole of full-grown oocytes. • A common transport machinery is employed in zebrafish and Xenopus oocytes. • The direction of mRNA transport depends on microtubule organization in oocytes. In zebrafish oocytes, cyclin B1 mRNAs are transported to the animal polar cytoplasm. To elucidate the molecular basis of cyclin B1 mRNA transport, we analyzed zebrafish Staufen1, a protein known to play a central role in mRNA transport to the vegetal pole of Xenopus oocytes. Zebrafish Staufen1 interacts with cyclin B1 mRNA throughout oocyte growth. Both cyclin B1 mRNA and Staufen1 are evenly distributed in the cytoplasm of young oocytes but are co-localized to the animal polar cytoplasm in later stages. Real-time imaging showed that the plus ends of oocyte microtubules are free in the cytoplasm in early stages but anchored to the animal polar cytoplasm in later stages. Transport of cyclin B1 reporter mRNA to the animal polar cytoplasm was inhibited by disruption of microtubules and injection of antibodies against Staufen1 or Kinesin1, a plus-end-directed microtubule motor that interacts with Staufen1, indicating that the transport depends on movement along microtubules toward the plus ends. Reporter mRNAs with an element required for the vegetal localization of vg1 mRNA in Xenopus oocytes were localized to the animal polar cytoplasm in zebrafish oocytes, indicating that the element is functional for animal polar localization in zebrafish oocytes. Our findings suggest that cyclin B1 mRNA-Staufen1 protein complexes are transported toward the animal pole of zebrafish oocytes by the plus-end-directed motor protein Kinesin1 along microtubules and that a common mRNA transport machinery functions in zebrafish and Xenopus oocytes, although its transport direction is opposite due to different organizations of microtubules.

60 APPLIED LIFE SCIENCES↗

Cisplatin sensitivity in breast cancer cells is associated with particular DMTF1 splice variant expression

The cyclin D binding myb-like transcription factor 1 (DMTF1) is a tumor suppressor gene that activates p14{sup ARF} transcription and thereby stabilizing the p53 tumor suppressor. The DMTF1 gene locus encodes for three different alternatively spliced isoforms, namely DMTF1α, β and γ. The oncogenic DMTF1β isoform negatively interferes with the transcriptional activity of DMTF1α. Increased DMTF1β is associated with increased cell proliferation in a variety of cancer cell types. In this study, we aimed at identifying the role of DMTF1 isoforms in response to cisplatin treatment in breast cancer cells. First, we used SKBR3 (cisplatin sensitive) and MCF7 (cisplatin resistant) breast cancer cell lines to quantify DMTF1 expression in response to cisplatin treatment. Total DMTF1 mRNA levels increased in a dose dependent manner in both cell lines upon cisplatin treatment. However, the mRNA levels of the isoforms revealed that the sensitive cell line, SKBR3, showed increased levels of both isoforms, whereas the resistant cell, MCF7, only showed increased levels of the oncogenic DMTF1β isoform. Silencing all DMTF1 isoforms led to increased cell survival upon cisplatin treatment. Furthermore, we found a significant increase in the percentage of quiescent cells in SKBR3 shDMTF1. Together, our data suggest that DMTF1 expression levels are associated with increased cisplatin resistance.

60 APPLIED LIFE SCIENCES↗

Fludrocortisone stimulates erythropoietin production in the intercalated cells of the collecting ducts

Erythropoietin has been thought to be secreted to plasma soon after the production because of the difficulty of Western blot analysis and immunohistochemistry. We established the new methods of Western blot analysis and immunohistochemistry. Using the new methods, we investigated the effects of aldosterone and fludrocortisone, an analogue of aldosterone on erythropoietin mRNA and protein production by the kidneys. Aldosterone stimulated Epo and HIF2α mRNA expressions in tubule suspensions and microdissected medullary thick ascending limbs and outer medullary collecting ducts. Western blot analysis showed a recombinant erythropoietin at 34–45 kDa and kidney erythropoietin at 36–40 and 42 kDa, both of which shifted to 22 kDa by deglycosylation. Erythropoietin protein expression was observed in the nephrons but not in the interstitial cells in control condition. Fludrocortisone stimulated erythropoietin mRNA and protein expressions in the distal nephrons, particularly in the intercalated cells of the collecting ducts. These data show that erythropoietin is produced by the nephrons by the regulation of renin-angiotensin-aldosterone system and not by the renal interstitial cells in control condition.

60 APPLIED LIFE SCIENCES↗

Activation of brown adipocytes by placental growth factor

Highlights: • In this study, 91 non-diabetic pregnant participants and 73 GDM patients were recruited to Gynaecology and Obstetrics Centre in Lu He hospital. • The direct effect of PlGF on BAT function was explored using the established human preadipocyte differentiation system. PlGF induced activation of human brown adipocytes. • PlGF stimulated mitochondrial function in brown adipocytes. • PlGF stimulated AMPKα phosphorylation in brown adipocytes. • PlGF reduced lipid content in the liver and increased BAT activity in db/db mice. Gestational diabetes mellitus (GDM) is a type of diabetes and occurs during pregnancy. Brown adipose tissue (BAT) improves glucose homeostasis and mitigates insulin resistance, however, its activity is reduced in GDM. Placenta growth factor (PlGF) is an angiogenic factor produced by placental trophoblasts. Nevertheless, whether and how PlGF could affect BAT function in GDM are not defined. To investigate this question, 91 non-diabetic pregnant participants and 73 GDM patients were recruited to Gynaecology and Obstetrics Centre in Lu He hospital. Serum levels of PlGF were quantified by ELISA. Skin temperature was measured by far infrared thermography in the supraclavicular region where classical BATs were located. The direct effect of PlGF on BAT function was explored using the established human preadipocyte differentiation system. Thereby, we demonstrated that serum levels of PlGF were lower in GDM patients compared with controls, which was accompanied by decreased skin temperature in the supraclavicular region. By qPCR and western blot, mRNA and protein expression of UCP1 and OXPHOS were elevated in differentiated adipocytes treated with PlGF. PlGF stimulated mitochondrion transcription and increased copy number of mitochondrial. When subjected for respirometry, PlGF-treated differentiated adipocytes showed higher oxygen consumption rates than controls. PlGF induced AMPK phosphorylation and blockade of AMPK phosphorylation blunted UCP1 and OXPHOS expression in differentiated adipocytes. PlGF administration reduced cholesterol and triglyceride content in the liver and improved insulin sensitivity in db mice compared with control. In Conclusion, PlGF could activate BAT function. Downregulation of PlGF might contribute to the reduced BAT activity in GDM.

60 APPLIED LIFE SCIENCES↗