Low endogenous glucocorticoid allows induction of kidney cortical cyclooxygenase-2 during postnatal rat development

In postnatal weeks 2–4, cyclooxygenase-2 (COX-2) is induced in the rat kidney cortex where it is critically involved in final stages of kidney development. We examined whether changes in circulating gluco- or mineralocorticosteroids or in their renal receptors regulate postnatal COX-2 induction. Plasma corticosterone concentration peaked at birth, decreased to low levels at days 3- 13, and increased to adult levels from day 22. Aldosterone peaked at birth and then stabilized at adult levels. Gluco- and mineralocorticoid receptor (GR and MR) mRNAs were expressed stably in kidney before, during, and after COX-2 induction. 11β-Hydroxysteroid dehydrogenase 2 was induced shortly after birth and was widely distributed in the whole collecting duct system in the suckling period and then returned to an adult pattern. Supplementation with corticosterone (20 mg·kg-1·day-1) or GR-specific dexamethasone (1 mg·kg-1·day-1) during low endogenous corticosterone suppressed renal COX-2 mRNA and protein and led to a restricted distribution of COX-2 immunolabeling. The ability of glucocorticoids to affect COX-2 was reflected in colocalization of GR-α and COX-2 immunoreactivity and mRNAs in thick ascending limb of Henle's loop. The MR antagonist potassium canrenoate (20 mg·kg-1·day-1) enhanced COX-2 expression from days 5 to 10, but low MR-specific concentrations of DOCA (1 mg·kg-1·day-1) had no effect on COX-2. Renomedullary interstitial cells expressed GR-α and COX-2. Dexamethasone suppressed COX-2 in these cells. Thus low plasma concentrations of corticosterone allowed for cortical and medullary COX-2 induction during postnatal kidney development. Increased circulating glucocorticoid in the postnatal period may damage late renal development through inhibition of COX-2.

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Early co-expression of cyclooxygenase-2 and renin in the rat kidney cortex contributes to the development of NG-nitro-l-arginine methyl ester induced hypertension

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2014-0347 ◽

2015 ◽

Vol 93 (4) ◽

pp. 299-308 ◽

Cited By ~ 5

Author(s):

Elizabeth Alejandrina Guzmán-Hernández ◽

Rafael Villalobos-Molina ◽

María Alicia Sánchez-Mendoza ◽

Leonardo Del Valle-Mondragón ◽

Gustavo Pastelín-Hernández ◽

...

Keyword(s):

Blood Pressure ◽

Methyl Ester ◽

Rat Kidney ◽

Cyclooxygenase 2 ◽

Kidney Cortex ◽

Ang Ii ◽

Rat Kidney Cortex ◽

Induced Hypertension ◽

Renin Mrna ◽

Cox 2

We investigated the involvement of cyclooxygenase-2 (COX-2) and the renin–angiotensin system in NG-nitro-l-arginine methyl ester (l-NAME)-induced hypertension. Male Wistar rats were treated with l-NAME (75.0 mg·(kg body mass)−1·day−1, in their drinking water) for different durations (1–33 days). COX-2 and renin mRNA were measured using real-time PCR in the renal cortex, and prostanoids were assessed in the renal perfusate, whereas angiotensin II (Ang II) and Ang (1-7) were quantified in plasma. In some rats, nitric oxide synthase inhibition was carried out in conjunction with oral administration of captopril (30.0 mg·kg−1·day−1) or celecoxib (1.0 mg·kg−1·day−1) for 2 or 19 days. We found a parallel increase in renocortical COX-2 and renin mRNA starting at day 2 of treatment with l-NAME, and both peaked at 19–25 days. In addition, l-NAME increased renal 6-Keto-PGF1α (prostacyclin (PGI2) metabolite) and plasma Ang II from day 2, but reduced plasma Ang (1-7) at day 19. Captopril prevented the increase in blood pressure, which was associated with lower plasma Ang II and increased COX-2-derived 6-Keto-PGF1α at day 2 and plasma Ang (1-7) at day 19. Celecoxib partially prevented the increase in blood pressure; this effect was associated with a reduction in plasma Ang II. These findings indicate that renal COX-2 expression increased in parallel with renin expression, renal PGI2 synthesis, and plasma Ang II in l-NAME-induced hypertension.

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Expression of Na-P(i) cotransport in rat kidney: localization by RT-PCR and immunohistochemistry

AJP Renal Physiology ◽

10.1152/ajprenal.1994.266.5.f767 ◽

1994 ◽

Vol 266 (5) ◽

pp. F767-F774 ◽

Cited By ~ 44

Author(s):

M. Custer ◽

M. Lotscher ◽

J. Biber ◽

H. Murer ◽

B. Kaissling

Keyword(s):

Transport System ◽

Polyclonal Antibodies ◽

Rat Kidney ◽

Proximal Tubules ◽

Expression Cloning ◽

Kidney Cortex ◽

Thick Ascending Limb ◽

Rt Pcr ◽

Rat Kidney Cortex ◽

Proximal Tubular

We have recently identified a rat kidney cortex Na-dependent transport system for phosphate (P(i)) by expression cloning (NaP(i)-2) (S. Magagnin, A. Werner, D. Markovich, V. Sorribas, G. Stange, J. Biber, and H. Murer. Proc. Natl. Acad. Sci. USA 90: 5979, 1993). In this study we have used reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry to establish the sites of expression of the NaP(i)-2-related mRNA and protein. RT-PCR was performed with single microdissected nephron segments. From these experiments we conclude that NaP(i)-2 mRNA is predominantly expressed in the proximal tubules of superficial and deep nephrons. No NaP(i)-2 mRNA was detected in the thick ascending limb of Henle's loop; however, faint NaP(i)-2 related PCR products were also observed in collecting ducts. Expression of the NaP(i)-2 protein was examined with the use of polyclonal antibodies raised against synthetic NaP(i)-2-derived peptides. Strong specific anti-NaP(i)-2 antiserum-mediated immunofluorescence was found in the convoluted part of proximal tubules and gradually decreased along the straight part. Immunofluorescence indicated that the NaP(i)-2 protein is present in the brush border of proximal tubular cells. In addition, NaP(i)-2-specific immunofluorescence was also observed in subapical vesicles. The described distribution of the NaP(i)-2 protein is in agreement with previously described nephron sites of P(i) reabsorption in the rat kidney and therefore suggests that the NaP(i)-2 transport system represents an Na-P(i) cotransporter involved in proximal tubular apical transport of phosphate.

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Renal localization and regulation of 15-hydroxyprostaglandin dehydrogenase

AJP Renal Physiology ◽

10.1152/ajprenal.00436.2007 ◽

2008 ◽

Vol 294 (2) ◽

pp. F433-F439 ◽

Cited By ~ 14

Author(s):

Bing Yao ◽

Jie Xu ◽

Raymond C. Harris ◽

Ming-Zhi Zhang

Keyword(s):

Proximal Tubule ◽

Cell Line ◽

Collecting Duct ◽

Macula Densa ◽

Immunofluorescent Staining ◽

Kidney Cortex ◽

Proximal Tubule Cell ◽

Thick Ascending Limb ◽

Key Enzyme ◽

Cox 2

Tissue prostaglandin levels are determined by both biosynthesis and catabolism. The current studies report the expression and localization of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a key enzyme in prostaglandin catabolism in the kidneys. We also investigated potential interactions between 15-PGDH and cyclooxygenase (COX), a key enzyme in prostaglandin biosynthesis. Both 15-PGDH mRNA and protein levels were significantly higher in kidney cortex than in papilla, which is opposite to the expression pattern of COX-2. In situ hybridization indicated that 15-PGDH mRNA was mainly localized to the tubular epithelial cells in kidney cortex and outer medulla but not in the glomerulus or papilla. Dual immunofluorescent staining indicated that 15-PGDH was expressed in the proximal tubule, cortical, and outer medullary thick ascending limb and collecting duct but not in the macula densa or papilla. 15-PGDH levels were significantly lower in a macula densa cell line (MMDD1) than in a proximal tubule cell line. Although a high-salt diet decreased COX-2 expression in macula densa, it increased macula densa 15-PGDH expression in both mouse and rat kidneys. In MMDD1 cells, a COX-2 inhibitor increased 15-PGDH, whereas a COX-1 inhibitor had no effect. Furthermore, intense 15-PGDH immunofluorescent staining was found in both macula densa and glomerulus in COX-2 knockout mice. The intrarenal distribution of 15-PGDH and its interactions with COX-2 suggest that differential regulation of COX-2 and 15-PGDH may play an important role in determining levels of prostaglandins involved in regulation of salt, volume, and blood pressure homeostasis.

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Ganglioside GM2-Activator Protein and Vesicular Transport in Collecting Duct Intercalated Cells

Journal of the American Society of Nephrology ◽

10.1681/asn.v103435 ◽

1999 ◽

Vol 10 (3) ◽

pp. 435-443

Author(s):

THOMAS M. MUNDEL ◽

HANS W. HEID ◽

DON J. MAHURAN ◽

WILHELM KRIZ ◽

PETER MUNDEL

Keyword(s):

Collecting Duct ◽

Rat Kidney ◽

The Body ◽

Kidney Cortex ◽

Intercalated Cells ◽

Rat Kidney Cortex ◽

Activator Protein ◽

Hexosaminidase A ◽

Gm2 Activator ◽

Gm2 Activator Protein

Abstract. This study describes the molecular characterization of an antigen defined by an autoantibody from a woman with habitual abortion as GM2-activator protein. The patient showed no disorder of renal function. Accidentally with routine serum screening for autoantibodies, an immunoreactivity was found in kidney collecting duct intercalated cells. Three distinct patterns of immunostaining of intercalated cells were observed: staining of the apical pole, basolateral pole, and diffuse cytoplasmic labeling. Ultrastructurally, the immunoreactivity was associated with “studs,” which represent the cytoplasmic domain of the vacuolar proton pump in intercalated cells. This pump is subjected to a shuttling mechanism from cytoplasmic stores to the cell membrane, which exclusively occurs in intercalated cells. Peptide sequences of a 23-kD protein purified from rat kidney cortex showed complete identity with corresponding sequences of GM2-activator protein. In the brain, GM2-activator protein is required for hexosaminidase A to split a sugar from ganglioside GM2. Because neither ganglioside GM2 nor GM1 (its precursor) is present in significant amounts in the kidney, the previous finding that this tissue contains the highest level of activator protein in the body was confusing. In this study, a novel role for GM2-activator protein in intercalated cells is proposed, and possible roles in the shuttling mechanism are discussed.

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Ultrastructural localization of Na-K-2Cl cotransporter in thick ascending limb and macula densa of rat kidney

AJP Renal Physiology ◽

10.1152/ajprenal.1998.275.6.f885 ◽

1998 ◽

Vol 275 (6) ◽

pp. F885-F893 ◽

Cited By ~ 63

Author(s):

Søren Nielsen ◽

Arvid B. Maunsbach ◽

Carolyn A. Ecelbarger ◽

Mark A. Knepper

Keyword(s):

Plasma Membrane ◽

Rat Kidney ◽

Ultrastructural Localization ◽

Macula Densa ◽

Tubuloglomerular Feedback ◽

Kidney Cortex ◽

Apical Plasma Membrane ◽

Thick Ascending Limb ◽

Rat Kidney Cortex ◽

Intracellular Vesicles

A bumetanide-sensitive Na-K-2Cl cotransporter, BSC-1, is believed to mediate the apical component of transcellular NaCl absorption in the thick ascending limb (TAL) of Henle’s loop. To study its ultrastructural localization in kidney, we used an affinity-purified, peptide-derived polyclonal antibody against rat BSC-1. Immunoblots from rat kidney cortex and outer medulla revealed a solitary 161-kDa band in membrane fractions. Immunocytochemistry of 1-μm cryosections demonstrated strong BSC-1 labeling of the apical and subapical regions of medullary and cortical TAL cells. Notably, macula densa cells also exhibited distinct labeling. Distal convoluted tubules and other renal tubule segments were unlabeled. Immunoelectron microscopy demonstrated that BSC-1 labeling was associated with the apical plasma membrane and with subapical intracellular vesicles in medullary and cortical TAL and in macula densa cells. Smooth-surfaced TAL cells, in particular, had extensive BSC-1 labeling of intracellular vesicles. These results support the view that BSC-1 provides the apical pathway for NaCl transport across the TAL and that an extensive intracellular reservoir of BSC-1 is present in a subpopulation of TAL cells. Furthermore, the BSC-1 localization in the apical plasma membrane of macula densa cells is consistent with its proposed role in tubuloglomerular feedback.

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Expression and developmental regulation of the NMDA receptor subunits in the kidney and cardiovascular system

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00629.2001 ◽

2002 ◽

Vol 283 (4) ◽

pp. R964-R971 ◽

Cited By ~ 52

Author(s):

Jocelyn C. Leung ◽

Brett R. Travis ◽

Jill W. Verlander ◽

Satinder K. Sandhu ◽

Song-Gui Yang ◽

...

Keyword(s):

Nmda Receptor ◽

Cardiovascular System ◽

Heart Development ◽

Kidney Development ◽

Rat Kidney ◽

Kidney Cortex ◽

Heart Cells ◽

Rat Kidney Cortex ◽

Subunit Protein ◽

Nr2 Subunits

Antagonists to the N-methyl-d-aspartate (NMDA) receptor bind to various extraneuronal tissues. We therefore assessed the expression of the main NMDA subunit, NR1, in various tissues. We demonstrate that NR1 appears to be most abundant in the rat kidney and heart. NR1 is present in total rat kidney, cortex, and medulla. Of the NR2 subunits, only the NR2C subunit protein is present in the kidney. The abundance of the NR1 subunit protein increases with kidney development. Both NR1 and NR2C are present in opossum kidney, Madin-Darby canine kidney, and LLC-PK1 cells. Immunohistochemistry studies show that the NR1 subunit is present in the renal proximal tubule. NR1 is abundant in the atrium and ventricle but is also expressed in the aorta and pulmonary artery. The NR2 subunits are not expressed in the heart. NR1 subunit protein expression is constant throughout heart development. Finally, the NR1 subunit protein is expressed in heart cells (H9c2) grown in culture. These studies reveal the presence of the NMDA receptor in the kidney and the cardiovascular system.

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Annexin A1 modulates macula densa function by inhibiting cyclooxygenase 2

AJP Renal Physiology ◽

10.1152/ajprenal.00704.2011 ◽

2012 ◽

Vol 303 (6) ◽

pp. F845-F854 ◽

Cited By ~ 4

Author(s):

S. Seidel ◽

H. Neymeyer ◽

T. Kahl ◽

T. Röschel ◽

K. Mutig ◽

...

Keyword(s):

Rat Kidney ◽

Juxtaglomerular Apparatus ◽

Inhibitory Effect ◽

Cyclooxygenase 2 ◽

Macula Densa ◽

Thick Ascending Limb ◽

Annexin A1 ◽

Glomerular Number ◽

Formyl Peptide ◽

Cox 2

Annexin A1 (ANXA1) exerts anti-inflammatory effects through multiple mechanisms including inhibition of prostaglandin synthesis. Once secreted, ANXA1 can bind to G protein-coupled formyl peptide receptors (Fpr) and activate diverse cellular signaling pathways. ANXA1 is known to be expressed in cells of the juxtaglomerular apparatus, but its relation to the expression of cyclooxygenase 2 (COX-2) in thick ascending limb and macula densa cells has not been elucidated. We hypothesized that ANXA1 regulates the biosynthesis of COX-2. ANXA1 abundance in rat kidney macula densa was extensively colocalized with COX-2 (95%). Furosemide, an established stimulus for COX-2 induction, caused enhanced expression of both ANXA1 and COX-2 with maintained colocalization (99%). In ANXA1-deficient mice, COX-2-positive cells were more numerous than in control mice (+107%; normalized to glomerular number; P < 0.05) and renin expression was increased (+566%; normalized to glomerular number; P < 0.05). Cultured macula densa cells transfected with full-length rat ANXA1 revealed downregulation of COX-2 mRNA (−59%; P < 0.05). Similarly, treatment with dexamethasone suppressed COX-2 mRNA in the cells (−49%; P < 0.05), while inducing ANXA1 mRNA (+56%; P < 0.05) and ANXA1 protein secretion. Inhibition of the ANXA-1 receptor Fpr1 with cyclosporin H blunted the effect of dexamethasone on COX-2 expression. These data show that ANXA1 exerts an inhibitory effect on COX-2 expression in the macula densa. ANXA1 may be a novel intrinsic modulator of renal juxtaglomerular regulation by inhibition of PGE2 synthesis.

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Lithium-induced NDI in rats is associated with loss of α-ENaC regulation by aldosterone in CCD

AJP Renal Physiology ◽

10.1152/ajprenal.00321.2005 ◽

2006 ◽

Vol 290 (5) ◽

pp. F1222-F1233 ◽

Cited By ~ 28

Author(s):

Jakob Nielsen ◽

Tae-Hwan Kwon ◽

Jørgen Frøkiær ◽

Mark A. Knepper ◽

Søren Nielsen

Keyword(s):

Protein Expression ◽

Collecting Duct ◽

Rat Kidney ◽

Lithium Treatment ◽

Lithium Concentration ◽

Fractional Excretion ◽

Kidney Cortex ◽

Cortical Collecting Duct ◽

Rat Kidney Cortex ◽

Fractional Excretion Of Sodium

Lithium-induced nephrogenic diabetes insipidus (Li-NDI) is associated with increased urinary sodium excretion and decreased responsiveness to aldosterone and vasopressin. Dysregulation of the epithelial sodium channel (ENaC) is thought to play an important role in renal sodium wasting. The effect of 7-day aldosterone and spironolactone treatment on regulation of ENaC in rat kidney cortex was investigated in rats with 3 wk of Li-NDI. Aldosterone treatment of rats with Li-NDI decreased fractional excretion of sodium (0.83 ± 0.02), whereas spironolactone did not change fractional excretion of sodium (1.10 ± 0.11) compared with rats treated with lithium alone (1.11 ± 0.05). Plasma lithium concentration was decreased by aldosterone (0.31 ± 0.03 mmol/l) but unchanged with spironolactone (0.84 ± 0.18 mmol/l) compared with rats treated with lithium alone (0.54 ± 0.04 mmol/l). Immunoblotting showed increased protein expression of α-ENaC, the 70-kDa form of γ-ENaC, and the Na-Cl cotransporter (NCC) in kidney cortex in aldosterone-treated rats, whereas spironolactone decreased α-ENaC and NCC compared with control rats treated with lithium alone. Immunohistochemistry confirmed increased expression of α-ENaC in the late distal convoluted tubule and connecting tubule and also revealed increased apical targeting of all three ENaC subunits (α, β, and γ) in aldosterone-treated rats compared with rats treated with lithium alone. Aldosterone did not, however, affect α-ENaC expression in the cortical collecting duct (CCD), which showed weak and dispersed labeling similar to that in rats treated with lithium alone. Spironolactone did not affect ENaC targeting compared with rats treated with lithium alone. This study shows a segment specific lack of aldosterone-mediated α-ENaC regulation in the CCD affecting both α-ENaC protein expression and trafficking, which may explain the increased sodium wasting associated with chronic lithium treatment.

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