scholarly journals mPGES-1 deletion potentiates urine concentrating capability after water deprivation

2012 ◽  
Vol 302 (8) ◽  
pp. F1005-F1012 ◽  
Author(s):  
Zhanjun Jia ◽  
Gang Liu ◽  
Maicy Downton ◽  
Zheng Dong ◽  
Aihua Zhang ◽  
...  
Keyword(s):  
Water Deprivation ◽  
Potential Role ◽  
Urine Volume ◽  
Renal Medulla ◽  
Urine Osmolality ◽  
Protein Abundance ◽  
Wild Type ◽  
Control Groups ◽  
Urine Concentrating Ability

PGE2 plays an important role in the regulation of fluid metabolism chiefly via antagonizing vasopressin-induced osmotic permeability in the distal nephron, but its enzymatic sources remain uncertain. The present study was undertaken to investigate the potential role of microsomal PGE synthase (mPGES)-1 in the regulation of urine concentrating ability after water deprivation (WD). Following 24-h WD, wild-type (WT) mice exhibited a significant reduction in urine volume, accompanied by a significant elevation in urine osmolality compared with control groups. In contrast, in response to WD, mPGES-1 knockout (KO) mice had much less urine volume and higher urine osmolality. Analysis of plasma volume by measurement of hematocrit and by using a nanoparticle-based method consistently demonstrated that dehydrated WT mice were volume depleted, which was significantly improved in the KO mice. WD induced a twofold increase in urinary PGE2 output in WT mice, which was completely blocked by mPGES-1 deletion. At baseline, the KO mice had a 20% increase in V2 receptor mRNA expression in the renal medulla but not the cortex compared with WT controls; the expression was unaffected by WD irrespective of the genotype. In response to WD, renal medullary aquaporin-2 (AQP2) mRNA exhibited a 60% increase in WT mice, and this increase was greater in the KO mice. Immunoblotting demonstrated increased renal medullary AQP2 protein abundance in both genotypes following WD, with a greater increase in the KO mice. Similar results were obtained by using immunohistochemistry. Paradoxically, plasma AVP response to WD seen in WT mice was absent in the KO mice. Taken together, these results suggest that mPGES-1-derived PGE2 reduces urine concentrating ability through suppression of renal medullary expression of V2 receptors and AQP2 but may enhance it by mediating the central AVP response.

scholarly journals Urea and urine concentrating ability in mice lacking AQP1 and AQP3

2006 ◽  
Vol 291 (2) ◽  
pp. F429-F438 ◽  
Author(s):  
Dan Zhao ◽  
Lise Bankir ◽  
Liman Qian ◽  
Dayu Yang ◽  
Baoxue Yang
Keyword(s):  
Time Course ◽  
Critical Role ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Solute Concentration ◽  
Urea Concentration ◽  
Wild Type ◽  
Concentrate Urea ◽  
Urine Concentrating Ability ◽  
Concentrating Defect

Aquaporin-1 (AQP1) and aquaporin-3 (AQP3) water channels expressed in the kidney play a critical role in the urine concentrating mechanism. Mice with AQP1 or AQP3 deletion have a urinary concentrating defect. To better characterize this defect, we studied the influence of an acute urea load (300 μmol ip) in conscious AQP1-null, AQP3-null, and wild-type mice. Urine was collected and assayed every 2 h, from 2 h before (baseline) to 8 h after the urea load. Mice of all genotypes excreted the urea load in ∼4 h with the same time course. Interestingly, despite their low baseline, the AQP3-null mice raised their urine osmolality and urea concentration progressively after the urea load to values almost equal to those in wild-type mice at 8 h. In contrast, urine non-urea solute concentration did not change. Urine volume fell in the last 4 h to about one-fourth of basal values. AQP1-null mice increased their urine flow rate much more than AQP3-null mice and showed no change in urine osmolality and urea concentration. The urea load strongly upregulated urea transporter UT-A3 expression in all three genotypes. These observations show that the lack of AQP3 does not interfere with the ability of the kidney to concentrate urea but impairs its ability to concentrate other solutes. This solute-selective response could result from the capacity of AQP3 to transport not only water but also urea. The results suggest a novel role for AQP3 in non-urea solute concentration in the urine.

scholarly journals Urine concentration in the diabetic mouse requires both urea and water transporters

2013 ◽  
Vol 304 (1) ◽  
pp. F103-F111 ◽  
Author(s):  
Titilayo O. Ilori ◽  
Mitsi A. Blount ◽  
Christopher F. Martin ◽  
Jeff M. Sands ◽  
Janet D. Klein
Keyword(s):  
Collecting Duct ◽  
Urine Osmolality ◽  
Diabetic Mouse ◽  
Urine Concentration ◽  
Diabetic Rat ◽  
Protein Abundance ◽  
Wild Type ◽  
Medullary Collecting Duct ◽  
Additional Stimulation

The regulation of the inner medullary collecting duct (IMCD) urea transporters (UT-A1, UT-A3) and aquaporin-2 (AQP2) and their interactions in diabetic animals is unknown. We investigated whether the urine concentrating defect in diabetic animals was a function of AQP2, the UT-As, or both transporters. UT-A1/UT-A3 knockout (UT-A1/A3 KO) mice produce dilute urine. We gave wild-type (WT) and UT-A1/A3 KO mice vasopressin via minipump for 7 days. In WT mice, vasopressin increased urine osmolality from 3,000 to 4,550 mosmol/kgH2O. In contrast, urine osmolality was low (800 mosmol/kgH2O) in the UT-A1/A3 KOs and remained low following vasopressin. Surprisingly, AQP2 protein abundance increased in UT-A1/A3 KO (114%) and WT (92%) mice. To define the role of UT-A1 and UT-A3 in the diabetic responses, WT and UT-A1/A3 KO mice were injected with streptozotocin (STZ). UT-A1/A3 KO mice showed only 40% survival at 7 days post-STZ injection compared with 70% in WT. AQP2 did not increase in the diabetic UT-A1/A3 KO mice compared with a 133% increase in WT diabetic mice. Biotinylation studies in rat IMCDs showed that membrane accumulation of UT-A1 increased by 68% in response to vasopressin in control rats but was unchanged by vasopressin in diabetic rat IMCDs. We conclude that, even with increased AQP2, UT-A1/UT-A3 is essential to optimal urine concentration. Furthermore, UT-A1 may be maximally membrane associated in diabetic rat inner medulla, making additional stimulation by vasopressin ineffective.

scholarly journals NMR and LC-MS-Based Metabolomics to Study Osmotic Stress in Lignan-Deficient Flax

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 767
Author(s):  
Kamar Hamade ◽  
Ophélie Fliniaux ◽  
Jean-Xavier Fontaine ◽  
Roland Molinié ◽  
Elvis Otogo Nnang ◽  
...  
Keyword(s):  
Stress Response ◽  
Osmotic Stress ◽  
Biosynthetic Pathway ◽  
Potential Role ◽  
Plant Secondary Metabolites ◽  
Wild Type ◽  
Osmotic Stress Response ◽  
Transgenic Flax ◽  
Insight Into

Lignans, phenolic plant secondary metabolites, are derived from the phenylpropanoid biosynthetic pathway. Although, being investigated for their health benefits in terms of antioxidant, antitumor, anti-inflammatory and antiviral properties, the role of these molecules in plants remains incompletely elucidated; a potential role in stress response mechanisms has been, however, proposed. In this study, a non-targeted metabolomic analysis of the roots, stems, and leaves of wild-type and PLR1-RNAi transgenic flax, devoid of (+) secoisolariciresinol diglucoside ((+) SDG)—the main flaxseed lignan, was performed using 1H-NMR and LC-MS, in order to obtain further insight into the involvement of lignan in the response of plant to osmotic stress. Results showed that wild-type and lignan-deficient flax plants have different metabolic responses after being exposed to osmotic stress conditions, but they both showed the capacity to induce an adaptive response to osmotic stress. These findings suggest the indirect involvement of lignans in osmotic stress response.

THE USE OF CHLORPROPAMIDE IN DIABETES INSIPIDUS IN CHILDREN

PEDIATRICS ◽  
1970 ◽  
Vol 45 (2) ◽  
pp. 236-245
Author(s):  
Robert M. Ehrlich ◽  
Sang Whay Kooh
Keyword(s):  
Diabetes Insipidus ◽  
Water Deprivation ◽  
Plasma Insulin ◽  
Urine Volume ◽  
Insulin Response ◽  
Urine Osmolality ◽  
Post Traumatic ◽  
Term Management ◽  
Plasma Insulin Response

Oral chlorpropamide was administered to 17 children with diabetes insipidus (D.I.). The cause of the D.I. was idiopathic, six; histiocytosis, five; craniopharyngioma, three; pinealoma, two, and post-traumatic, one. Twenty-four-hour urine volume and measurements of serum and urine osmolality at the beginning and end of a 7-hour water deprivation test were used to evaluatechlorpropamide therapy. Administration of 150 to 400 mg of chlorpropamide per day by mouth caused a reduction in urine volume in all patients (range 8 to 67%). No change in aldosterone, 17-hydroxycorticoids, or electrolyte excretion was noted. Serum electrolytes and glomerular filtration rate were not affected by therapy. Glucose tolerance and plasma insulin response remained normal in those patients tested. Mild leucine sensitivity without significant change in plasma insulin was induced in four children. During water deprivation, seven patients with secondary D.I. but only one with idiopathic D.I. produced hypertonic urine. Hypoglycemia developed in seven children and is the major hazard of treatment. Long-term management of D.I. has been possible in nine children. Oral chlorpropamide is a useful drug in children with vasopressin-sensitive diabetes insipidus.

Abstract 450: The Role of CD38 as a Therapeutic Target for Protection Against Doxorubicin-induced Cardiotoxicity Through Nad+ Boosting

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Thais R Peclat ◽  
Guillermo Agorrody ◽  
Lilian S Gomez ◽  
Eduardo N Chini
Keyword(s):  
Single Dose ◽  
Therapeutic Target ◽  
Potential Role ◽  
Damage Mechanism ◽  
Treated Group ◽  
Wild Type ◽  
Chemotherapeutic Treatment ◽  
Positive Effect ◽  
Dose Injection

Background: Doxorubicin is a chemotherapy medication used to treat several types of cancer. Its major adverse effect is cardiotoxicity, which may limit its use. Doxorubicin-induced cardiotoxicity (DIC), once developed, carries a poor prognosis. Therefore strategies to prevent or treat DIC are of paramount importance but have not yet been fully developed. Being NAD + a critical nucleotide which is involved in oxy-reduction reactions and CD38 the main NAD + -consuming enzyme responsible for NAD levels regulation and homeostasis, we aim to investigate the link of CD38 and NAD + metabolism in DIC and its potential role as a therapeutic target. Methods: We compared Wild-type (WT) control mice with WT mice treated with a single dose injection of 15 mg/kg of doxorubicin who received vehicle or an antibody that blocksCD38 ecto-enzymatic activity. We also compared genetically CD38 catalytic inactive (CI) mice treated or not with the same single dose injection. Results: Doxorubicin caused a decrease in Ejection Fraction (EF) in WT mice. We also observed that CD38 CI mice treated with doxorubicin did not have changes in EF compared to their control. When compared to WT receiving just doxorubicin, WT mice treated also with the antibody had a trend to improve EF. As for exercise performance, our results show a decrease in exercise capacity induced by doxorubicin that was reversed in the antibody group and did not happen in the CD38 CI mice treated with doxorubicin. Doxorubicin caused a decrease in heart rate variability (HRV) which was improved in the antibody treated group. Moreover, our results show a survival rate that is similar to what has been previously shown, with 50% mortality associated with doxorubicin. Blockage of CD38 activity with antibody reduced mortality in this model to approximately 20%. Mechanistically, we did not observe decreases in NAD+ levels induced by Doxorubicin. However, boost of NAD induced by blocking CD38 was related to protection against DIC. Conclusion: Our results indicate that the damage mechanism of DIC may not be related directly with NAD decrease, but NAD boosting induced by CD38 blockage seems to have a positive effect in protection against cardiac dysfunction related to this chemotherapeutic treatment.

scholarly journals Manganese promotes the aggregation and prion-like cell-to-cell exosomal transmission of α-synuclein

2019 ◽  
Vol 12 (572) ◽  
pp. eaau4543 ◽  
Author(s):  
Dilshan S. Harischandra ◽  
Dharmin Rokad ◽  
Matthew L. Neal ◽  
Shivani Ghaisas ◽  
Sireesha Manne ◽  
...  
Keyword(s):  
Potential Role ◽  
Neuronal Model ◽  
Experimental Models ◽  
Bimolecular Fluorescence Complementation ◽  
Wild Type ◽  
Biological Mechanisms ◽  
Extracellular Medium ◽  
Cell To Cell Transfer ◽  
Serum Exosomes

The aggregation of α-synuclein (αSyn) is considered a key pathophysiological feature of certain neurodegenerative disorders, collectively termed synucleinopathies. Given that a prion-like, cell-to-cell transfer of misfolded αSyn has been recognized in the spreading of αSyn pathology in synucleinopathies, we investigated the biological mechanisms underlying the propagation of the disease with respect to environmental neurotoxic stress. Considering the potential role of the divalent metal manganese (Mn2+) in protein aggregation, we characterized its effect on αSyn misfolding and transmission in experimental models of Parkinson’s disease. In cultured dopaminergic neuronal cells stably expressing wild-type human αSyn, misfolded αSyn was secreted through exosomes into the extracellular medium upon Mn2+ exposure. These exosomes were endocytosed through caveolae into primary microglial cells, thereby mounting neuroinflammatory responses. Furthermore, Mn2+-elicited exosomes exerted a neurotoxic effect in a human dopaminergic neuronal model (LUHMES cells). Moreover, bimolecular fluorescence complementation (BiFC) analysis revealed that Mn2+ accelerated the cell-to-cell transmission of αSyn, resulting in dopaminergic neurotoxicity in a mouse model of Mn2+ exposure. Welders exposed to Mn2+ had increased misfolded αSyn content in their serum exosomes. Stereotaxically delivering αSyn-containing exosomes, isolated from Mn2+-treated αSyn-expressing cells, into the striatum initiated Parkinsonian-like pathological features in mice. Together, these results indicate that Mn2+ exposure promotes αSyn secretion in exosomal vesicles, which subsequently evokes proinflammatory and neurodegenerative responses in both cell culture and animal models.

Prevention of two-kidney, one-clip renal hypertension in rat by ablation of AV3V tissue

1983 ◽  
Vol 245 (4) ◽  
pp. H683-H689 ◽  
Author(s):  
J. R. Haywood ◽  
G. D. Fink ◽  
J. Buggy ◽  
S. Boutelle ◽  
A. K. Johnson ◽  
...  
Keyword(s):  
Renal Artery ◽  
Third Ventricle ◽  
Renal Hypertension ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Sham Operation ◽  
Vasopressin Release ◽  
Transient Rise ◽  
Fluid Regulation

This study examined the role of the anteroventral third ventricle (AV3V) in the renin-dependent two-kidney, one-clip model of renal hypertension. AV3V lesion and sham lesion rats were subjected to the placement of a clip on one renal artery or a sham operation. The sham lesion-renal artery clip rats experienced an increase in systolic blood pressure; however, AV3V lesioned animals experienced only a transient rise in arterial pressure during the 1st wk after clip. Body fluid regulation studies during the course of the hypertension revealed that there were no differences in water intake and urine volume between the lesion- and sham lesion-renal artery clip animals. Although significantly greater plasma and blood volumes were demonstrated in the AV3V lesion-sham clip rats compared with sham lesion animals, no differences in vascular volumes were detected in the renal artery clip rats. Finally, the rats were water deprived for 3 days to maximally stimulate vasopressin release. Urine osmolality increased significantly in all groups of rats except the AV3V lesion-renal artery clip animals protected against the hypertension.

scholarly journals Targeting myeloid-cell specific integrin α9β1 inhibits arterial thrombosis in mice

Blood ◽  
2020 ◽  
Vol 135 (11) ◽  
pp. 857-861 ◽  
Author(s):  
Nirav Dhanesha ◽  
Manasa K. Nayak ◽  
Prakash Doddapattar ◽  
Manish Jain ◽  
Gagan D. Flora ◽  
...  
Keyword(s):  
Arterial Thrombosis ◽  
Potential Role ◽  
Myeloid Cell ◽  
Neutrophil Extracellular Traps ◽  
Cathepsin G ◽  
Wild Type ◽  
Extracellular Traps ◽  
Laser Injury ◽  
Activated Platelets

Abstract Evidence suggests that neutrophils contribute to thrombosis via several mechanisms, including neutrophil extracellular traps (NETs) formation. Integrin α9β1 is highly expressed on neutrophils when compared with monocytes. It undergoes affinity upregulation on neutrophil activation, and stabilizes adhesion to the activated endothelium. The role of integrin α9 in arterial thrombosis remains unexplored. We generated novel myeloid cell-specific integrin α9−/− mice (α9fl/flLysMCre+) to study the role of integrin α9 in arterial thrombosis. α9fl/fl littermates were used as controls. We report that α9fl/flLysMCre+ mice were less susceptible to arterial thrombosis in ferric chloride (FeCl3) and laser injury-induced thrombosis models with unaltered hemostasis. Neutrophil elastase-positive cells were significantly reduced in α9fl/flLysMCre+ mice concomitant with reduction in neutrophil count, myeloperoxidase levels, and red blood cells in the FeCl3 injury-induced carotid thrombus. The percentage of cells releasing NETs was significantly reduced in α9fl/flLysMCre+ mouse neutrophils stimulated with thrombin-activated platelets. Furthermore, we found a significant decrease in neutrophil-mediated platelet aggregation and cathepsin-G secretion in α9fl/flLysMCre+ mice. Transfusion of α9fl/fl neutrophils in α9fl/flLysMCre+ mice restored thrombosis similar to α9fl/fl mice. Treatment of wild-type mice with anti-integrin α9 antibody inhibited arterial thrombosis. This study identifies the potential role of integrin α9 in modulating arterial thrombosis.

scholarly journals Cloning of wheat keto-acyl thiolase 2B reveals a role of jasmonic acid in grain weight determination

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Yun Chen ◽  
Yan Yan ◽  
Tian-Tian Wu ◽  
Guo-Liang Zhang ◽  
Huanran Yin ◽  
...  
Keyword(s):  
Jasmonic Acid ◽  
Potential Role ◽  
Wheat Yield ◽  
Grain Weight ◽  
Wild Type ◽  
Wheat Improvement ◽  
Stop Mutation ◽  
Enhanced Expression ◽  
Component Traits

AbstractGrain weight (GW) is one of the component traits of wheat yield. Existing reports have shown that multiple phytohormones are involved in the regulation of GW in different crops. However, the potential role of jasmonic acid (JA) remains unclear. Here, we report that triticale grain weight 1 (tgw1) mutant, with marked reductions in both GW and JA content, is caused by a premature stop mutation in keto-acyl thiolase 2B (KAT-2B) involved in β-oxidation during JA synthesis. KAT-2B overexpression increases GW in wild type and boosts yield. Additionally, KAT-2B compliments the grain defect in tgw1 and rescues the lethal phenotype of the Arabidopsis kat2 mutant in a sucrose-free medium. Despite the suppression of JA synthesis in tgw1 mutant, ABA synthesis is upregulated, which is accompanied by enhanced expression of SAG3 and reduction of chlorophyll content in leaves. Together, these results demonstrate a role of the JA synthetic gene KAT-2B in controlling GW and its potential application value for wheat improvement.

Early polyuria and urinary concentrating defect in potassium deprivation

2000 ◽  
Vol 279 (4) ◽  
pp. F655-F663 ◽  
Author(s):  
Hassane Amlal ◽  
Carissa M. Krane ◽  
Qian Chen ◽  
Manoocher Soleimani
Keyword(s):  
Time Course ◽  
Northern Blot Analysis ◽  
Urine Volume ◽  
Urine Osmolality ◽  
Immunoblot Analysis ◽  
Early Event ◽  
Protein Abundance ◽  
Outer Medulla ◽  
Potassium Deprivation ◽  
Concentrating Defect

The time course of the onset of nephrogenic diabetes insipidus and its relationship to aquaporin-2 (AQP2) expression in K+ deprivation (KD) remains unknown. Rats were fed a K+-free diet and killed after 12 h, 1, 2, 3, 6, or 21 days. Serum K+ concentration was decreased only after, but not before, 3 days of a K+-free diet. Urine osmolality, however, decreased as early as 12 h of KD (1,061 ± 26 vs. 1,487 ± 102 mosmol/kgH2O in control, P < 0.01). It decreased further at 24 h (to 858 ± 162 mosmol/kgH2O in KD, P < 0.004) and remained low at 21 days of KD (436 ± 58 mosmol/kgH2O, P < 0.0001 compared with baseline). Water intake decreased at 12 h ( P < 0.002) but increased at 24 h ( P < 0.05) and remained elevated at 21 days of KD. Urine volume increased at 24 h of KD (8 ± 2 to 15 ± 2 ml/24 h, P < 0.05) and remained elevated at 21 days. Immunoblot analysis demonstrated that AQP2 protein abundance in the outer medulla remained unchanged at 12 h ( P > 0.05), decreased at 24 h (∼44%, P < 0.001), and remained suppressed (∼52%, P < 0.03) at 21 days of KD. In the inner medulla the AQP2 protein abundance remained unchanged at both 12 and 24 h of KD. AQP2 protein abundance in the cortex, however, decreased at 12 h (∼47%, P < 0.01) and remained suppressed at 24 h (∼77%, P < 0.001) of KD. Northern blot analysis showed that AQP2 mRNA decreased as early as 12 h of KD in both cortex ( P < 0.02) and outer medulla ( P < 0.01) and remained suppressed afterward. In conclusion, the urinary concentrating defect in KD is an early event and precedes the onset of hypokalemia. These studies further suggest that the very early urinary concentrating defect in KD (after 12 but before 24 h) results primarily from the suppression of cortical AQP2, whereas the later onset of a urinary concentrating defect (after 24 h) also involves a downregulation of medullary AQP2.

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