Effects of ZnCl2 on ROS generation, plasma membrane properties, and changes in protein expression in grapevine root explants

Member 4 of human solute carrier family 7 (SLC7A4) exhibits significant sequence homology with the SLC7 subfamily of human cationic amino acid transporters (hCATs) [Sperandeo, Borsani, Incerti, Zollo, Rossi, Zuffardi, Castaldo, Taglialatela, Andria and Sebastio (1998) Genomics 49, 230–236]. It is therefore often referred to as hCAT-4 even though no convincing transport activity has been shown for this protein. We expressed SLC7A4 in Xenopus laevis oocytes, but could not detect any transport activity for cationic, neutral or anionic amino acids or for the polyamine putrescine. In addition, human glioblastoma cells stably overexpressing a fusion protein between SLC7A4 and the enhanced green fluorescent protein (EGFP) did not exhibit an increased transport activity for l-arginine. The lack of transport activity was not due to a lack of SLC7A4 protein expression in the plasma membrane, as in both cell types SLC7A4-EGFP exhibited a similar subcellular localization and level of protein expression as functional hCAT-EGFP proteins. The expression of SLC7A4 can be induced in NT2 teratocarcinoma cells by treatment with retinoic acid. However, also for this endogenously expressed SLC7A4, we could not detect any transport activity for l-arginine. Our data demonstrate that the expression of SLC7A4 in the plasma membrane is not sufficient to induce an amino acid transport activity in X. laevis oocytes or human cells. Therefore, SLC7A4 is either not an amino acid transporter or it needs additional (protein) factor(s) to be functional.

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Melatonin Effect on Cryopreserved Sperm Cells of Crioulo Stallions

Open Access Journal of Veterinary Science & Research ◽

10.23880/oajvsr-16000202 ◽

2020 ◽

Vol 5 (2) ◽

pp. 1-8

Author(s):

Eraldo L Zanella

Keyword(s):

Plasma Membrane ◽

Sperm Motility ◽

Membrane Integrity ◽

Male Gamete ◽

The Body ◽

Cellular Damage ◽

Ros Generation ◽

Sperm Cells ◽

Beneficial Effects ◽

Endogenous Antioxidant

The freezing/thawing process of spermatozoa can cause cellular damage to the male gamete, decreasing the fertilization potential due to the increase in the production of reactive oxygen species (ROS). Melatonin is a potent endogenous antioxidant that protects the body against the damage caused by ROS. This study has evaluated different melatonin concentrations on the sperm viability of cryopreserved semen of Crioulo stallions. For that, three ejaculates were collected from five stallions diluted in a commercial extender followed by centrifugation and resuspension in a commercial freezing extender supplemented with 0; 1.25; 2.5. 5mM of Melatonin before the cryopreservation process. After thawing, the evaluation was performed assessing motility and flow cytometry evaluations: the plasma membrane integrity (PI), the integrity of the acrosomal membrane (FITC-PNA), mitochondrial membrane potential (JC1), and ROS generation (DCF-DA). Our results showed that sperm motility in the group without Melatonin and the 1.25mM group did not show the difference; however, the groups 2.5mM and 5mM presented a reduction in sperm motility. The 1.25 mM concentration was able to protect the plasma membrane during the cryopreservation process, in addition to showing a significant reduction in the production of ROS and increasing the percentage of sperm with integral acrosome. It can also be seen that high concentrations of Melatonin did not show beneficial effects. In conclusion, the addition of 1.25 mM of the Melatonin in Crioulo sperm cells showed to have a protective effect on the sperm cell during cryopreservation.

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Abstract 16216: Increases in Renal Nkcc2 and Ncc Preceded the Elevation of Blood Pressure in Mice Treated With Clozapine

Circulation ◽

10.1161/circ.142.suppl_3.16216 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Zhiyun Ren ◽

Laureano D Asico ◽

Xiaoyan Wang

Keyword(s):

Protein Expression ◽

Sodium Transport ◽

Transport Proteins ◽

No Synthase ◽

Ros Generation ◽

Serum Concentrations ◽

Drug Induced ◽

Induced Hypertension ◽

Different Doses ◽

Mini Pump

One of major side effects of clozapine, a common antipsychotic drug, is hypertension. In order to explore the pathogenesis of the drug-induced hypertension, we examined the renal sodium transport proteins and BP in the C57Bl6/J male mice treated with clozapine at different doses for 1 week. Clozapine at 20mg/kg/day via osmotic mini-pump increased SBP ( 110±0.6,mmHg, femoral artery, under anesthesia) and DBP (76.7±1) relative to vehicle (97.6±1.2/71.2±2.7) while the renal protein expression of NKCC2 (180±21, % of vehicle) and NCC (171±22), and ENaC-α (140±7), β(166±21) and γ(130±7) was increased without changes in NHE3 and α1-NKA (n=5/group). Clozapine at lower doses (5&10mg/kg/day,IP) did not change the conscious SBP and DBP monitored daily by tail-cuff, even on day 7 in 5 mg/kg group (115.61±1.6/90.1±1.3) and in 10mg/kg group (116.8±2/89.0±1.6) relative to vehicle (111.9±1.5/86.9±1.4) (n=4/group). Urinary excretion of Na + & K + and serum concentrations of Na + , K + , Cl - , creatinine were similar in all groups. However, renal protein expression of NKCC2 was increased in 5mg/kg (360±80, % of vehicle) and 10mg/kg (247±50) groups; NCC was increased at 5 mg/kg (175±9); α1-NKA was increased in 5mg/kg (216±5) and 10mg/kg (163±2) groups. No increases were found in the protein expression of NHE3 and ENaCs. Those increases in renal NKCC2 &NCC at 5 & 10 mg/kg were consistent with those at 20 mg/kg. AT1R was increased at 5 (221±20) &10mg/kg (255±21) while renin (186±15) and ACE1 (186±5), not ACE2, were increased at 5 mg/kg suggesting an activation of RAAS in kidney. NOX4, not NOX2, was increased at 5 mg/kg (453±69) while NOS3, not NOS1&2, was decreased at 5 (60±21) and 10mg/kg (64±5) groups. TNFα, not IL-6 was increased at 5 (222±18) &10 mg/kg (321±26). In cultured mouse distal convoluted tubule cells, clozapine also increased NCC and α1-NKA at 1nM (169±4;156±7) and 10nm(175±23;183±15) respectively ( 24h,n=4/group). Those changes in kidney, including increases in sodium transport proteins, RAAS components, ROS generation enzymes, inflammation factors and decrease in NO synthase, preceded the elevation of BP suggesting that direct or indirect regulations of clozapine on those proteins may play an important role in the pathogenesis of the drug-induced hypertension.

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Mal protein stabilizes luminal membrane PLC-β3 and negatively regulates ENaC in mouse cortical collecting duct cells

AJP Renal Physiology ◽

10.1152/ajprenal.00446.2018 ◽

2019 ◽

Vol 317 (4) ◽

pp. F986-F995

Author(s):

Kubra M. Tuna ◽

Bing-Chen Liu ◽

Qiang Yue ◽

Zinah M. Ghazi ◽

He-Ping Ma ◽

...

Keyword(s):

Plasma Membrane ◽

Protein Expression ◽

Collecting Duct ◽

Renal Tubules ◽

Cortical Collecting Duct ◽

Open Probability ◽

Anionic Phospholipid ◽

Kinase Substrate ◽

Luminal Membrane ◽

Collecting Duct Cells

Abnormally high epithelial Na+ channel (ENaC) activity in the aldosterone-sensitive distal nephron and collecting duct leads to hypertension. Myelin and lymphocyte (Mal) is a lipid raft-associated protein that has been previously shown to regulate Na+-K-2Cl− cotransporter and aquaporin-2 in the kidney, but it is not known whether it regulates renal ENaC. ENaC activity is positively regulated by the anionic phospholipid phosphate phosphatidylinositol 4,5-bisphosphate (PIP2). Members of the myristoylated alanine-rich C-kinase substrate (MARCKS) family increase PIP2 concentrations at the plasma membrane, whereas hydrolysis of PIP2 by phospholipase C (PLC) reduces PIP2 abundance. Our hypothesis was that Mal protein negatively regulates renal ENaC activity by stabilizing PLC protein expression at the luminal plasma membrane. We investigated the association between Mal, MARCKS-like protein, and ENaC. We showed Mal colocalizes with PLC-β3 in lipid rafts and positively regulates its protein expression, thereby reducing PIP2 availability at the plasma membrane. Kidneys of 129Sv mice injected with MAL shRNA lentivirus resulted in increased ENaC open probability in split-open renal tubules. Overexpression of Mal protein in mouse cortical collecting duct (mpkCCD) cells resulted in an increase in PLC-β3 protein expression at the plasma membrane. siRNA-mediated knockdown of MAL in mpkCCD cells resulted in a decrease in PLC-β3 protein expression and an increase in PIP2 abundance. Moreover, kidneys from salt-loaded mice showed less Mal membrane protein expression compared with non-salt-loaded mice. Taken together, Mal protein may play an essential role in the negative feedback of ENaC gating in principal cells of the collecting duct.

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Methylprednisolone inhibits uptake of Ca2+ and Na+ ions into concanavalin A-stimulated thymocytes

Biochemical Journal ◽

10.1042/bj3260329 ◽

1997 ◽

Vol 326 (2) ◽

pp. 329-332 ◽

Cited By ~ 38

Author(s):

Frank BUTTGEREIT ◽

Stefan KRAUSS ◽

Martin D. BRAND

Keyword(s):

Plasma Membrane ◽

Concanavalin A ◽

Membrane Properties ◽

Mitochondrial Electron Transport Chain ◽

Oxidation Reactions ◽

Transport Chain ◽

Cord Injury ◽

Na Ions ◽

Atp Supply ◽

Na Uptake

The glucocorticoid drug methylprednisolone inhibits respiration in concanavalin A-stimulated rat thymocytes at concentrations that are relevant to its acute clinical efficacy against autoimmune diseases and spinal cord injury. Methylprednisolone affects several processes, including ion cycling, substrate oxidation reactions and RNA/DNA synthesis. The inhibition of respiration used to drive ATP-consuming cycles of Ca2+ and Na+ ions across the plasma membrane has been proposed to be either primary or secondary to restriction of cellular ATP supply. By comparing the effects of methylprednisolone with those of myxothiazol, an inhibitor of the mitochondrial electron transport chain, we show that the effects of methylprednisolone on Ca2+ and Na+ cycling are primary. We propose that methylprednisolone acts by affecting membrane properties to inhibit Ca2+ and Na+ uptake across the plasma membrane and to increase H+ uptake across the mitochondrial membrane, and that other effects are secondary.

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310. CAVEOLIN 1 AND 2 IN THE UTERUS DURING EARLY PREGNANCY

Reproduction Fertility and Development ◽

10.1071/srb10abs310 ◽

2010 ◽

Vol 22 (9) ◽

pp. 110

Author(s):

R. J. Madawala ◽

C. R. Murphy

Keyword(s):

Plasma Membrane ◽

Epithelial Cells ◽

Protein Expression ◽

Early Pregnancy ◽

Basolateral Membrane ◽

Membrane Curvature ◽

Major Protein ◽

Uterine Epithelial Cells ◽

Caveolin 1 ◽

Blastocyst Implantation

Rat uterine epithelial cells undergo many changes during early pregnancy in order to become receptive to blastocyst implantation. These changes include basolateral folding and the presence of vesicles of various sizes which are at their greatest number during the pre-implantation period. The present study investigated the possible role that caveolin 1 and 2 plays in this remodelling specifically days 1, 3, 6, 7, and 9 of pregnancy. Caveolin is a major protein in omega shaped invaginations of the plasma membrane called caveolae that are considered to be specialised plasma membrane subdomains. Caveolae are rich in cholesterol, glycosphingolipids, and GPI anchored proteins and are involved in endocytosis and membrane curvature. Immunofluorescence microscopy has shown caveolin 1 and 2 on day 1 of pregnancy are localised to the cytoplasm of luminal uterine epithelial cells, and by day 6 of pregnancy (the time of implantation), it concentrates basally. By day 9 of pregnancy, expression of both caveolin 1 and 2 in luminal uterine epithelia is cytoplasmic as seen on day 1 of pregnancy. A corresponding increase in protein expression of caveolin 1 on day 6 of pregnancy in luminal uterine epithelia was observed. Interestingly however, caveolin 2 protein expression decreases at the time of implantation as found by western blot analysis. Both caveolin 1 and 2 were localised to blood vessels within the endometrium and myometrium and also the muscle of the myometrium in all days of pregnancy studied. In addition, both caveolin 1 and 2 were absent from glandular epithelium, which is interesting considering that they do not undergo the plasma membrane transformation. The localisation and expression of caveolin 1 and 2 in rat luminal uterine epithelium at the time of implantation suggest possible roles in trafficking of cholesterol and/or various proteins for either degradation or relocation. Caveolins may contribute to the morphology of the basolateral membrane seen on day 6 of pregnancy. All of which may play an important role during successful blastocyst implantation.

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Immunolocalisation and expression of oxytocin receptors and sex hormone-binding globulin in the testis and epididymis of dogs: correlation with sperm function

Reproduction Fertility and Development ◽

10.1071/rd18452 ◽

2019 ◽

Vol 31 (9) ◽

pp. 1434

Author(s):

Andressa Dalmazzo ◽

João D. A. Losano ◽

Daniel S. R. Angrimani ◽

Isabel V. A. Pereira ◽

Marcelo D. Goissis ◽

...

Keyword(s):

Plasma Membrane ◽

Protein Expression ◽

Membrane Integrity ◽

Sex Hormone ◽

Sex Hormone Binding Globulin ◽

Mitochondrial Activity ◽

Hormone Binding ◽

Plasma Membrane Integrity ◽

Gene And Protein Expression ◽

Acrosome Integrity

The aim of this study was to confirm gene and protein expression of oxytocin receptor (OTR) and sex hormone-binding globulin (SHBG) in the testis and epididymis of dogs, correlating these data with sperm quality and production and testosterone concentrations. Positive correlations were found between OTR and SHBG expression in both the testis and epididymis. Testicular OTR expression was positively associated with plasma membrane and acrosome integrity in canine spermatozoa, whereas SHBG expression in the testis was positively correlated with various sperm characteristics, such as sperm concentration, total and progressive motility, plasma membrane integrity and acrosome integrity. Testicular expression of both OTR and SHBG was negatively correlated with low sperm mitochondrial activity. In the epididymis, SHBG expression was only positively correlated with plasma membrane integrity. Analysis of protein expression revealed that testicular OTR was positively correlated with testosterone concentrations and negatively correlated with the absence of sperm mitochondrial activity. In addition, SHBG expression in the testes was associated with epididymis SHBG expression and morphologically normal cells. Immunohistochemical (IHC) analysis revealed the presence of both OTR and SHBG in testicular smooth muscles and Leydig cells. However, in the epididymis, OTR was only located in smooth muscle cells, whereas neither IHC nor western blotting detected SHBG. Together, the results of this study suggest that OTR and SHBG play key roles in spermatogenesis and sperm maturation, being essential for male reproductive success.

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Dehydroepiandrosterone Prevents H2O2-Induced BRL-3A Cell Oxidative Damage through Activation of PI3K/Akt Pathways rather than MAPK Pathways

Oxidative Medicine and Cellular Longevity ◽

10.1155/2019/2985956 ◽

2019 ◽

Vol 2019 ◽

pp. 1-14

Author(s):

Longlong Li ◽

Yao Yao ◽

Zhihao Jiang ◽

Jinlong Zhao ◽

Ji Cao ◽

...

Keyword(s):

Oxidative Stress ◽

Protein Expression ◽

Signaling Pathways ◽

Hormone Receptors ◽

Mapk Signaling ◽

Ros Generation ◽

Protective Effects ◽

Pi3k Inhibitor Ly294002 ◽

Beneficial Effects

Dehydroepiandrosterone (DHEA) is a popular dietary supplement that has well-known benefits in animals and humans, but there is not enough information about the mechanisms underlying its effects. The present study aimed at investigating these mechanisms through in vitro experiments on the effects of DHEA on rat liver BRL-3A cells exposed to oxidative stress through H2O2. The findings showed that DHEA increased the antioxidant enzyme activity, decreased ROS generation, and inhibited apoptosis in H2O2-treated cells. These effects of DHEA were not observed when the cells were pretreated with known antagonists of sex hormones (Trilostane, Flutamide, or Fulvestrant). Furthermore, treatment with estradiol and testosterone did not have the same protective effects as DHEA. Thus, the beneficial effects of DHEA were associated with mechanisms that were independent of steroid hormone pathways. With regard to the mechanism underlying the antiapoptotic effect of DHEA, pretreatment with DHEA was found to induce a significant decrease in the protein expression of Bax and caspase-3 and a significant increase in the protein expression of PI3K and p-Akt in H2O2-treated BRL-3A cells. These effects of DHEA were abolished when the cells were pretreated with the PI3K inhibitor LY294002. No changes were observed on the p-ERK1/2, p-p38, and p-JNK protein levels in H2O2-induced BRL-3A cells pretreated with DHEA. In conclusion, our data demonstrate that DHEA protects BRL-3A cells against H2O2-induced oxidative stress and apoptosis through mechanisms that do not involve its biotransformation into steroid hormones or the activation of sex hormone receptors. Importantly, the protective effect of DHEA on BRL-3A cells was mainly associated with PI3K/Akt signaling pathways, rather than MAPK signaling pathways.

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Insulin Stimulates GLUT4 Trafficking to the Syncytiotrophoblast Basal Plasma Membrane in the Human Placenta

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/jc.2018-02778 ◽

2019 ◽

Vol 104 (9) ◽

pp. 4225-4238 ◽

Cited By ~ 7

Author(s):

Laura B James-Allan ◽

Jaron Arbet ◽

Stephanie B Teal ◽

Theresa L Powell ◽

Thomas Jansson

Keyword(s):

Plasma Membrane ◽

Protein Expression ◽

Membrane Trafficking ◽

Human Placenta ◽

Plasma Membranes ◽

Glucose Transporter ◽

Maternal Obesity ◽

Normal Body Mass Index ◽

Basal Plasma Membrane ◽

Basal Plasma

AbstractContextPlacental transport capacity influences fetal glucose supply. The syncytiotrophoblast is the transporting epithelium in the human placenta, expressing glucose transporters (GLUTs) and insulin receptors (IRs) in its maternal-facing microvillous plasma membrane (MVM) and fetal-facing basal plasma membrane (BM).ObjectiveThe objectives of this study were to (i) determine the expression of the insulin-sensitive GLUT4 glucose transporter and IR in the syncytiotrophoblast plasma membranes across gestation in normal pregnancy and in pregnancies complicated by maternal obesity, and (ii) assess the effect of insulin on GLUT4 plasma membrane trafficking in human placental explants.Design, Setting, and ParticipantsPlacental tissue was collected across gestation from women with normal body mass index (BMI) and mothers with obesity with appropriate for gestational age and macrosomic infants. MVM and BM were isolated.Main Outcome MeasuresProtein expression of GLUT4, GLUT1, and IR were determined by western blot.ResultsGLUT4 was exclusively expressed in the BM, and IR was predominantly expressed in the MVM, with increasing expression across gestation. BM GLUT1 expression was increased and BM GLUT4 expression was decreased in women with obesity delivering macrosomic babies. In placental villous explants, incubation with insulin stimulated Akt (S473) phosphorylation (+76%, P = 0.0003, n = 13) independent of maternal BMI and increased BM GLUT4 protein expression (+77%, P = 0.0013, n = 7) in placentas from lean women but not women with obesity.ConclusionWe propose that maternal insulin stimulates placental glucose transport by promoting GLUT4 trafficking to the BM, which may enhance glucose transfer to the fetus in response to postprandial hyperinsulinemia in women with normal BMI.

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